Patent Application
20080058495
The present invention may be understood more readily by reference to the following detailed description of the invention, and to the examples provided. It is to be understood that this invention is not limited to the specific processes and conditions described, because specific processes and process conditions for processing plastic articles may vary. It is also to be understood that the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting. It is further understood that although the various embodiments may achieve one or more advantages, the claimed invention is not restricted to those advantages, nor need all the advantages be obtained in every instance.
As used in the specification and the claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. For example, reference to processing a thermoplastic “preform,” “container” or “bottle” is intended to include the processing of a plurality of thermoplastic preforms, articles, containers, or bottles.
By “comprising” or “containing” we mean that at least the named compound, element, particle, etc. must be present in the composition or article, but does not exclude the presence of other compounds, materials, particles, etc., even if the other such compounds, material, particles, etc. have the same function as what is named.
As used herein, a particle size or median particle size means the d50 particle size, which is the median diameter, where 50% of the volume is composed of particles larger than the stated d50 value, and 50% of the volume is composed of particles smaller than the stated d50 value. The particle size may be measured with a laser diffraction type particle size distribution meter, or scanning or transmission electron microscopy methods, or size exclusion chromatography. Alternatively, the particle size can be correlated by a percentage of particles screened through a mesh.
In one embodiment of the invention, there is provided a process for increasing the yellowness of a polyester polymer, comprising adding:
to a melt phase polymerization process for manufacturing a polyester polymer composition. Preferably, the polyester polymer composition has a b* ranging from −5 to +5, or above −2 to +5, or −2 to +3, or 0 to +3. Desirably, the polymer contains a combination of the yellow colorant and an orange colorant, or a red colorant, or a combination thereof. Moreover, the polymer desirably has a preform a* color value ranging from −4 to 2. Each feature is now described in further detail below.
The melt phase polymerization process is desirably continuous, but may also be conducted in a batch mode. In one embodiment, the melt phase process, whether batch or continuous, produces 10 metric tons of polyester polymer per year, or at least 30 metric tons, or at least 60 metric tons, or at least 100 metric tons, or at least 130 metric tons of polyester polymer per year, and the process is preferably continuous and the particles produced by the process are preferably made in a continuous process.
Reheat agent particles are particles which improve the reheat rate of the polyester polymer in which they are distributed. The reheat agent particles are titanium based particles within the polymer matrix. The reheat agent particles comprise titanium, titanium nitride, titanium boride, titanium carbide, or combinations thereof.
An improvement in the reheat rate means that the compositions reheat faster (increased reheat rate), or with less reheat energy (increased reheat efficiency), or both, compared to the same polyester composition without these titanium based reheat agent particles. A convenient measure is the reheat improvement temperature (RIT) of the compositions, as further defined herein.
In one embodiment, the reheat agent particles may provide one or more of the following effects to the polyester polymer, preform, and/or bottle made thereby in addition to improving the reheat properties of the polyester compositions in which they are distributed: a bluing agent to increase the blue tint of the polyester compositions in which they are distributed; and improving the UV-blocking properties of the polyester compositions in which they are distributed. Of course, the polyester compositions of the invention may have additional effects beyond those just given, and the invention is intended to encompass such additional effects as well.
Some titanium-based reheat agent particles increase the blue color of the polymer. This may be observed by a decrease in the b* value, as measured using the CIELAB scale, as further described herein, relative to the absence of the reheat agent particles. For example, the b* value may be lowered by at least 1 unit, or at least 2 units, or at least 3 units, or at least 5 units, or at least 8 units, or at least 10 units by the addition of the reheat agent particles.
The L* of the preforms and bottles may vary depending upon the desired application. In one embodiment, the polyester polymer particles, and articles made thereby including preforms and bottles, desirably have an L* of at least 65, or at least 68, or at least 70, or at least 72, or at least 75.
The reheat agents also provide, in a preferred embodiment, an increase in the UV-blocking effect by observing an increased resistance of the contents of a container to the effects of ultraviolet light. This phenomenon can be determined by visual inspection of contents such as dyes that degrade over time in the presence of UV light. Alternatively, the UV-blocking effect of the polyester compositions of the invention can be measured by UV-VIS measurements, such as by using a HP8453 Ultraviolet-Visible Diode Array Spectrometer, performed from a wavelength ranging from 200 nm to 460 nm. An effective comparison measure using this equipment would be a reduction in the percent of UV transmission rate at 370 nm, the polyester compositions of the invention typically obtaining a reduction of at least 5%, or at least 10%, or at least 20% when compared with polyester compositions without the reheat agent particles. For example, if the unmodified polymer exhibits a transmission rate of 80%, and the modified polymer exhibits a transmission rate of 60%, the reduction would be a reduction of 25%. Any other suitable measure of the ability of the polyester compositions to block a portion of the UV light incident upon the compositions may likewise be used. A suitable sample thickness, for purposes of approximating the thickness of a bottle side-wall, might be, for example, 0.012 inches thick, or from 0.008 to 0.020 inches thick.
One of the reheat agent particles which are useful in the invention comprises titanium nitride. Titanium nitride is commonly considered to be a compound of titanium and nitrogen in which there is approximately a one-to-one correspondence between titanium atoms and nitrogen atoms. However, it is known in the art of metallurgy that titanium nitride, having a cubic NaCl-type structure, is stable over a wide range of anion or cation deficiencies, for example in relative amounts from TiN0.42 to TiN1.0, or even, for example, to TiN1.16,(for example, if titanium nitride is prepared at low temperatures by reacting NH3 with TiCl4, see pg. 87, Transition Metal Carbides and Nitrides, by Louis E. Toth, 1971, Academic Press (London), incorporated herein by reference) all of which compounds are intended to fall within the scope of the invention.
Although titanium nitride particles are one kind of reheat agent particle suitable for use in the invention, the titanium nitride particles may comprise significant amounts of titanium carbide and/or titanium oxide, so long as the titanium nitride particles are comprised of significant amounts of the titanium nitride, or so long as the total amount of titanium nitride and titanium carbide is at least 50 wt. %, for example. Thus, the titanium nitride may have relative amounts of titanium, carbon, and nitrogen within a wide range, such as a relative stoichiometry up to TiC0.5N0.5, or to TiC0.8N0.2, or to TiC0.7N0.3 or even greater, with the carbon replacing nitrogen, and with the relative amounts of titanium to nitrogen (or nitrogen and carbon) as already described. Of course, the amount of titanium carbide phase which is present in the particles is not at all critical
Titanium nitride compounds useful according to the claimed invention include those further described in Kirk-Othmer Encyclopedia of Chemical Technology, Vol 24, 4th ed., (1997) pp. 225-349, and especially pp. 231-232, the relevant portions of which are incorporated herein by reference.
Titanium nitride particles useful according to the claimed invention may be distinguished from other titanium compounds, such as those used as condensation catalysts, for example titanium alkoxides or simple chelates. That is, if titanium compounds are used as condensation catalysts to form the polymer in the compositions of the claimed invention, such polymers will additionally contain the reheat agent particles as described herein.
The reheat agent particles and in particular titanium nitride particles, in one embodiment, have a median particle size of less than 0.04 micrometers (μm), and a relatively narrow particle size distribution, are advantageous as both bluing agents and reheat additives.
The reheat particles may include one or more other metals or impurities, so long as the particles are comprised of significant amounts of the specified titanium containing particles. Preferably, the amount of other metals or non-metals present in the particles is preferably no more than 50 wt. % of the particle, such other elements including aluminum, tin, zirconium, manganese, germanium, iron, chromium, tungsten, molybdenum, vanadium, palladium, ruthenium, niobium, tantalum, cobalt, nickel, copper, gold, silver, silicon, and hydrogen, as well as carbon and oxygen, as already described. In another aspect, the amount of other metals or non-metals, other than carbon, nitrogen, or boron, present in the particles is no more than 40 wt. %, or no more than 30 wt. %, or no more than 20 wt. %, or no more than 10 wt. %, or no more than 5 wt. %, or no more than 3 wt. % of the reheat agent particle, such other elements including aluminum, tin, zirconium, manganese, germanium, iron, chromium, tungsten, molybdenum, vanadium, palladium, ruthenium, niobium, tantalum, cobalt, nickel, copper, gold, silver, silicon, oxygen, and hydrogen.
The reheat agent particles may comprise at least 50 wt. %, or at least 60 wt. %, or at least 75 wt. %, or at least 90 wt. %, or at least 95 wt. % titanium nitride, titanium, titanium boride, titanium carbide, or combinations thereof.
The particles may be hollow spheres or spheroids coated with one or more of the elements or compounds described as the reheat agent particles. The coating thickness should be sufficient to provide adequate reheat properties. Thus, in various embodiments, the thickness of the coating may be from 0.005 μm to 10 μm, or from 0.01 μm to 5 μm, or from 0.01 μm to 0.5 μm. Alternatively, the coating thickness may range even smaller, such as from 0.5 nm to 100 nm, or from 0.5 nm to 50 nm, or from 0.5 nm to 10 nm.
The amount of reheat agent particles present in the polyester compositions according to the invention may vary within a range, for example from 0.5 ppm, or from 1 ppm, or from 2 ppm, or from 3 ppm, up to 1,000 ppm, or up to 500 ppm, or up to 200 ppm, or up to 100 ppm, or up to 50 ppm, or up to 25 ppm, or up to 15 ppm, or up to 13 ppm, or up to 10 ppm, or up to 8 ppm, or up to 7 ppm, or up to 6 ppm, or up to 5 ppm. For example, in some instances, loadings from 1 ppm to 20 ppm, or 2 to 18 ppm, or 3 to 15 ppm, or 3 to 10 ppm, or 3 to 7 ppm, may be entirely adequate for improved reheat.
It should be noted that titanium nitride particles can be produced by numerous techniques, such as reacting the metal or oxide of titanium with nitrogen, or by plasma arc vapor synthesis, in which TiCl4 is reacted with NH3. Further details are described in the Powder Metallurgy entry in Kirk-Othmer Encyclopedia of Chemical Technology, Vol 16, 4th ed., (1995) pp. 353-392; details can also be found in Transition Metal Carbides and Nitrides by L. E. Toth, Academic Press 1971, pp 1-28, each of which is incorporated herein by reference. The titanium nitride particles according to the invention may thus be produced by any known means, without limitation.
Shapes of reheat agent particles which can be used in this invention include, but are not limited to, the following: acicular powder, angular powder, dendritic powder, equi-axed powder, flake powder, fragmented powder, granular powder, irregular powder, nodular powder, platelet powder, porous powder, rounded powder, and spherical powder. The particles may be of a filamentary structure, where the individual particles may be loose aggregates of smaller particles attached to form a bead or chain-like structure. The overall size of the particles may be variable, due to a variation in chain length and degree of branching.
In further embodiments, there is provided reheat agent particles, such as titanium nitride, having a particle size from 1 nm to 500 nm, or from 1 nm to 300 nm, or from 10 nm to 100 nm, or from 10 nm to 80 nm, present at a concentration ranging from 1 ppm to 100 ppm, or from 3 ppm to 30 ppm, or from 3 ppm to 15 ppm, or any other range as described above.
The reheat agent particles may have irregular shapes and form chain-like structures, although roughly spherical particles may be preferred. The particle size and particle size distribution may be measured by methods such as those described in the Size Measurement of Particles entry of Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 22, 4th ed., (1997) pp. 256-278, incorporated herein by reference. For example, particle size and particle size distributions may be determined using a Fisher Subsieve Sizer or a Microtrac Particle-Size Analyzer manufactured by Leeds and Northrop Company, or by microscopic techniques, such as scanning electron microscopy or transmission electron microscopy.
A range of particle size distributions may be useful according to the invention. The particle size distribution, as used herein, may be expressed by “span (S),” where S is calculated by the following equation:
where d90 represents a particle size in which 90% of the volume is composed of particles having a diameter smaller than the stated d90; and d10 represents a particle size in which 10% of the volume is composed of particles having a diameter smaller than the stated d10; and d50 represents a particle size in which 50% of the volume is composed of particles having a diameter larger than the stated d50 value, and 50% of the volume is composed of particles having a diameter smaller than the stated d50 value.
Thus, particle size distributions in which the span (S) is from 0 to 10, or from 0 to 5, or from 0.01 to 2, for example, may be used according to the invention. Alternatively, the particle size distribution (S) may range even broader, such as from 0 to 15, or from 0 to 25, or from 0 to 50.
In order to obtain a good dispersion of particles in the polyester compositions, a solid concentrate containing for example 300 ppm to 1000 ppm particles, or from 300 ppm to 1 wt %, or up to 40 wt %, or even higher, may be prepared using a polyester polymer. The concentrate may then be let down into a polyester at the desired concentration in the finished polymer, preform, or container, ranging in amounts as already described above. Alternatively, the reheat agent particles may be mixed in a liquid carrier as a slurry, dispersion, or emulsion and added to a polymerization melt phase polymerization process or to a melt processing zone fed with polyester polymer particles such as an extruder or an injection molding machine. The liquid carrier may be an inert solvent or a carrier reactive with the reactants used to make the polyester polymer or with the polyester polymer itself.
The location of the reheat agent particles within the polyester compositions is not limited. The particles may be disposed anywhere on or within the polyester polymer, pellet, preform, or bottle. Preferably, the polyester polymer in the form of a pellet forms a continuous phase. By being distributed “within” the continuous phase we mean that the particles are found at least within a portion of a cross-sectional cut of the pellet. The particles may be distributed within the polyester polymer randomly, distributed within discrete regions, or distributed only within a portion of the polymer. In a specific embodiment, the particles are disposed randomly throughout the polyester polymer composition as by way of adding the particles to a melt, or by mixing the particles with a solid polyester composition followed by melting and mixing.
The method by which the particles are incorporated into the polyester composition is illustrated by but not limited to the following. The particles can be added to the melt phase polymerization process, such as during esterification or ester exchange, during polycondensation, at any point in-between the reaction vessels or pipes, or after polycondensation but before solidification; or may be added to a melt processing zone fed by the polyester polymer particles or to the polymer melt within the melt processing zone, such as may be found in extruder barrels or injection molding machines; or may be added as a solid/solid blend with powder or pellets. They may be added at locations including, but not limited to, proximate the inlet to an esterification reactor, proximate the outlet of an esterification reactor, at a point between the inlet and the outlet of an esterification reactor, anywhere along a recirculation loop, proximate the inlet to a prepolymer reactor, proximate the outlet to a prepolymer reactor, at a point between the inlet and the outlet of a prepolymer reactor, proximate the inlet to a polycondensation reactor, or proximal to the outlet of a polycondensation final reactor, or at a point between the inlet and the outlet of a polycondensation reactor, or at a point after the outlet of a polycondensation reactor, preferably a final polycondensation reactor, and before a die for forming pellets.
In another aspect, the reheat agent particles may be added to a polyester polymer and fed to a melt processing zone (for ease referred to interchangeably with an extruder or an injection molding machine), fed by polyester polymer particles by any method, including feeding the reheat agent particles to the molten polymer in the injection molding machine, or by combining the reheat agent particles with a feed of polyester polymer to the injection molding machine, either by melt blending or by dry blending pellets and particles. The particles may be supplied neat, or in a concentrate form in a polyester polymer, or as a dispersion in a liquid or solid carrier. Examples of suitable carriers include carriers reactive with the polyester polymer or reactants used to form polyester polymer, and unreactive carriers. Reactive carriers desirably have number average molecular weight up to 8000, or up to 6000, or up to 5000, or up to 4000, or up to 3000, or up to 2000, and at least 50, or at least 100, or at least 200, or at least 300, or at least 400, or at least 500. Examples include ethylene glycol, polyethylene glycol, and glycerol monostearate. The carrier forms an emulsion, dispersion or slurry with the particles.
A concentrate may be added to a bulk polyester or anywhere along the different stages for manufacturing PET, in a manner such that the concentrate is compatible with the bulk polyester or its precursors. For example, the point of addition or the It.V. of the concentrate may be chosen such that the It.V. of the polyethylene terephthalate and the It.V. of the concentrate are similar, e.g. ±0.2 It.V. A concentrate can be made with an It.V. ranging from 0.3 dL/g to 1.1 dL/g to match the typical It.V. of a polyethylene terephthalate under manufacture in the polycondensation stage. Alternatively, a concentrate can be made with an It.V. similar to that of solid-stated pellets used at the injection molding stage (e.g. It.V. from 0.6 dL/g to 1.1 dL/g).
The particles may be added to an esterification reactor, such as with and through the ethylene glycol feed optionally combined with a phosphorus compound, to a prepolymer reactor, to a polycondensation reactor, or to solid pellets in a reactor for solid stating, or at any point in-between any of these stages. In each of these cases, the particles may be combined with PET or its precursors neat, as a concentrate containing PET, or diluted with a carrier. The carrier may be reactive to PET or may be non-reactive. The particles, whether neat or in a concentrate or in a carrier, and the bulk polyester, may be dried prior to mixing together. These particles may be dried in an atmosphere of dried air or other inert gas, such as nitrogen, and if desired, under sub-atmospheric pressure. Desirably, the reheat agent particles are added after esterification is complete (e.g. greater than 80% conversion), or added between esterification and polycondensation, or added to a polycondensation zone.
The impact of a reheat agent particle on the blue or yellow color of the polymer can be judged using the CIELAB scale. The b* value measures yellow to blue with yellow having positive values and blue negative values.
Color measurement theory and practice are discussed in greater detail in Principles of Color Technology, pp. 25-66 by Fred W. Billmeyer, Jr., John Wiley & Sons, New York (1981), incorporated herein by reference.
The CIELAB value (L*, a*, b*), for the purpose of measurement, is made on twenty-ounce bottle preforms having an outer diameter of 0.846 inches and a sidewall cross-sectional thickness of 0.154 inches, Specifying a particular preform a* or b* color value does not imply that the composition is a preform or that a preform having a particular sidewall cross-sectional thickness is actually used, but only that in the event the b* is measured on the composition in whatever form the composition may be found, the polyester composition employed is, for purposes of testing and evaluating the b* of the composition, injection molded to make a preform having a thickness of 0.154 inches, and the b* of that preform is measured. The results of the b* measurement on that preform determines the b* value of the composition in whatever form the composition may be. Thus, specifying a particular b* value or b* value range of a melt, powder, particle, preform, or bottle means that when the composition is made into a preform as described above for measurement purposes, the b* value of the preform will correspond to the stated b* value or be within the stated range, or the preform used to make the bottle will have a b* value as stated or be within the stated range. The same applies with respect to L* and a* determinations.
In one embodiment, the b* color coordinate value of the polyester composition, including solid polyester polymer particles, preform, or bottle ranges from greater than −5, or at least −4, or at least −3, or at least −2.5, or at least −2.0, or at least −1.5, or at least −1.0, or at least −0.5, and up to +5, or up to +4, or up to +3, or up to +2.5, or up to +2.0, or up to +1.5, or up to +1.0, or up to +0.5. Exemplary ranges are −3.0 up to +3.0, or −2.5 up to +2.5.
In another embodiment, the a* color coordinate value of the polyester composition, including solid polyester polymer particles, preform or bottle ranges from greater than −4, or at least −3, or at least −2.5 and up to 2, or up to 1. Exemplary ranges are −4 to 2, or −3 to 2, or −2.5 to 1. The polyester polymer, bottles, and preforms desirably have any one of these stated ranges in combination with the b* ranges described above, such as a b* range of −5 to +5 and an a* ranging from −4 to 2, or a b* ranging from above −2 to 4 or 0 to 4 and an a* ranging from −3 to 2.
In a preferred embodiment, the reheat agent particles will decrease the b* coordinate value of the polyester polymer, preform, or bottle. The b* coordinate value of the polyester polymer, preform, or bottle may decrease (move in a direction more towards blue) by at least 1 unit, or at least 2 units, or at least 3 units, or at least 5 units, or at least 8 units, or at least 10 units by the addition of the reheat agent particles, relative to the same composition without said reheat agent particles.
In another aspect of the invention, the b* coordinate value of the polyester polymer composition particles, preforms, or bottles, is less than 0.0, or less than −1.0 (less than being in a bluer direction, or less than −3.0, or less than −5.0, or less than −6.0, or less than −7.0, or less than −8.0, or less than −9.0, all the way down to −20, or down to −15, if measured in the absence of the yellow colorant in the polyester polymer composition particles, preforms, or bottles.
The instrument used for measuring CIELAB color should have the capabilities of a HunterLab UltraScan XE, which is a diffuse/8° spectrophotometer. The scale employed is the CIELAB scale (L*, a*, b*) with D65 illuminant and 10° observer calculated according to guidelines of ASTM E 308. Preforms are tested in transmission mode whereby the preform is placed halfway between the sphere port and the detector port and is held in place in the instrument using a preform holder, available from HunterLab. The large-area view (1 inch diameter light beam) option is employed. Triplicate measurements are averaged, whereby the sample is rotated 90° around its center axis between each measurement.
The intrinsic viscosity (It.V.) values described throughout this description are set forth in dL/g unit and calculated according to ASTM D 4603, whereby the inherent viscosity (Ih.V.) is measured at 30° C. in 60/40 wt/wt phenol/tetrachloroethane at a concentration of 0.5 g/dL.
The following test for reheat improvement temperature (RIT) is used herein, in order to determine the reheat improvement of the compositions. Twenty-ounce bottle preforms (with an outer diameter of 0.846 inches and a sidewall cross-sectional thickness of 0.154 inches) are run through the oven bank of a Sidel SBO2/3 blow molding unit. The lamp settings for the Sidel blow molding unit are shown in Table 1. The preform heating time in the heaters is 38 seconds, and the power output to the quartz infrared heaters is set at 64%.
In the test, a series of fifteen preforms is passed in front of the quartz infrared heaters and the average preform surface temperature of the middle five preforms is measured. All preforms are tested in a consistent manner. The preform reheat improvement temperature (RIT) is then calculated by comparing the difference in preform surface temperature of the target samples containing a reheat additive with that of the same polymer having no reheat additive. The higher the RIT value, the higher the reheat rate of the composition.
Thus, in various embodiments, the twenty-ounce bottle preform reheat improvement temperature of the polyester compositions according to the claimed invention containing the reheat agent particles, may be at least 0.1° C., or at least 1° C., or at least 2° C., or at least 3° C., or at least 4° C., or at least 5° C., or at least 6° C., and/or up to 32° C., or up to 20° C., or up to 15° C., or up to 11° C.
The polyester polymer particles preferably comprise at least 80 wt. % polyester polymer, or at least 85 wt %, or at least 90 wt %, or at least 95 wt %, or at least 98 wt. %, or at least 99 wt. %, or 100 wt. % polyester polymer relative to all other polymers (but not inorganic material or fibers or fillers) present in the particles.
As noted above, there is provided a process for increasing the yellowness of a polyester polymer, comprising adding:
to a melt phase polymerization process for manufacturing a polyester polymer.
Yellow colorants are colorants that are yellow to the eye. These colorants desirably absorb light in the visible light spectrum at wavelengths within the range of 400 nm to 470 nm. The λmax may fall inside or outside of this range, provided that the colorant absorbs light in this range. In one embodiment, the yellow colorant absorbs light within the range of 400 to 470 nm and the λmax of the yellow colorant falls outside of this range. In another embodiment, yellow colorant absorbs light within the range of 400 to 470 nm and the λmax of the yellow colorant is less than 400 nm. In another embodiment, the λmax of the yellow colorant is within a range of 400 to 470 nm, or from 420 to 460 nm. In another embodiment, the λmax of the yellow colorant is within a range of 400 to 470 nm, or from 420 to 460 nm, and the yellow colorant also absorbs uv light at less than 400 nm, or within the range of 330 nm to 400 nm.
The band width of the yellow colorant is not particularly limited. In one embodiment, the half band width is least 100 nm. A broad spectrum is desirable in applications where one desires to absorb some uv light below 400 nm, yet have a yellow hue to the colorant due to absorbing light in the yellow spectrum ranging from 400 nm to 470 nm. In another embodiment, the half band width is less than 100 nm, or 80 nm or less, or 60 nm or less, or 50 nm or less, or 40 nm or less.
The yellow colorant is desirably soluble in the polyester polymer at the levels used and in the polyester polymer to which they are added. Yellow colorants that are not soluble in the polyester polymer to which they are added tend to cause the formation of specks in the polymer, or render the polymer hazy or unclear. Thus, to provide for a high clarity polymer that is bright (L* of at least 65), with no visible speck formation, the yellow colorant is desirably soluble, meaning sufficiently soluble so as to avoid the formation of specks or haze caused by the colorant.
In another embodiment, the yellow colorant is reactive with the polyester polymer reactants or the polyester polymer or both. In yet a further embodiment, the yellow colorant is a yellow colorant, absorbs UV light, and is reactive.
As further described below, the polyester polymer may contain colorants other than the yellow colorant in addition to the yellow colorant, such as orange or red colorants.
The colorants may be added to a melt phase polymerization for making the polyester polymer, or added to a melt processing zone fed by polyester polymer particles for making articles or compounded or melt blended particles. In the melt phase polymerization the colorants can be added to the esterification zone, to the polycondensation zone, or to conduits between the reactor vessels. Whether the colorants are added to a melt phase polymerization process or to a melt processing zone fed by polyester polymer particles, in each case, the yellow colorant may be added as a solid concentrate, or in a liquid carrier (also known as a paste, solution, slurry, dispersion, or emulsion), or neat.
When the colorant is added to a polyester polymer in a liquid carrier, the carrier may be inert or reactive. If using a reactive carrier, it is preferable used to add colorant to a melt phase polymerization process rather than to a melt processing zone where transesterification reactions occur and break down the It.V. of the polymer without any ability to recover and build back up the molecular weight. Inert liquid carriers for the yellow colorant should be compatible with the polyester polymer. The colorant may be suspended (dispersion or emulsion) or dissolved in the liquid carrier.
Desirably, the liquid carrier is non-aqueous and soluble in the polyester polymer so as to achieve uniform distribution of the colorants throughout the polymer. The carrier desirably also has a boiling point greater than the temperature at which the polyester polymer is processed either in the melt phase polymerization, an extruder barrel, or the barrel of an injection molding machine. Suitable carriers include hydrocarbons, mono-hydroxyl functional compounds such as alcohols, esters, and combinations thereof. Suitable reactive carriers include polyfunctional hydroxyl compounds such as diols.
Specific examples of liquid carriers include the hydrocarbon oils and vegetable oils, or the refined versions thereof. Such carriers are available commercially from ColorMatrix as Clearslip™ and ColorMatrix LCPY-1: 82-89 Series. Examples of diols as reactive carriers include ethylene glycol and polyethylene glycols (PEG's) and cyclic anhydrides.
A solid concentrate containing the yellow colorant and/or any other colorant may also be used and has the advantage that the concentrate is highly compatible since the polymers are of the same type as the bulk polymer in the melt processing zone or in the melt phase polymerization zone. Suitable polymers for making solid concentrates include polyester polymers and polyamide polymers, preferably polyester polymers. Desirably, the It.V. of the polyester polymer in the solid concentrate is within ±0.10, or ±0.05, or ±0.03 It.V. of the polyester polymer being fed to the melt processing zone for making articles or particles. The amount of yellow colorant in a solid concentrate is at least 10 ppm, or at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 200 ppm, or at least 400 ppm, or at least 500 ppm, or at least 750 ppm, or at least 1000 ppm, or at least 2000 ppm, or at least 3000 ppm, or at least 5000 ppm, or at least 6000 ppm, or at least 8000 ppm, or at least 10,000 ppm, and up to about 30 wt. %, or up to about 20 wt. %, or up to 10 wt. %, or up to 5 wt. %, based on the weight of the concentrate.
The yellow colorant and/or other colorants employed are desirably heat stable in the polymerization or molding environment. The yellow colorants, or other colorants employed, may optionally be copolymerizable with the polyester polymer either in the melt phase polymerization for making the polyester polymer or in a melt processing zone fed by polyester polymers and a yellow colorant. They are preferably not extractable from the polymer during normal use and handling of the articles and desirably do not affect the physical properties (other than color) of the articles in which they appear.
Yellow colorants useful in this invention include C.I. Solvent Yellows 98, 103, 105, 113, 116, 133, 157, 162, 176, and 187; C.I. Disperse Yellows 49, 54, 64, 77, 88, 89, 93, 118, 160, 200, and 201; C.I. Pigment Yellows 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 24, 42, 55, 62, 63, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 108, 109, 110, 111, 113, 120, 127, 128, 129, 130, 133, 136, 138, 139, 147, 150, 151, 154, 155, 156, 168, 169, 174, 175, 180, 181, 190, 191, 194, 199, and C.I. Vat Yellows 1, 3, and 20. Natural colorants and other synthetic monomeric and polymeric colorants and organometallic compounds are useful, such as those containing moieties of or residues of mono or diazo compounds, isoindolinone compounds, anthraquinone compounds, benzimidazolone compounds, azo metal complexes, methine compounds, quinophthalones, and naphthalidimide compounds, especially the methine and anthraquinone dyes that are yellow.
Other yellow organic dyes and pigments include Naphthol Yellow S, Hansa Yellow (10G, 5G, GR, A, RN, R and G), yellow iron oxide, Chrome Yellow, Titan Yellow, Oil Yellow, Pigment Yellow L, Benzidine Yellow (G and GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G and R), Tartrazine Lake, Quinoline Yellow Lake, and Anthrazane Yellow BGL.
The molecular weight of the yellow colorant is not particularly limited. The molecular weight typically ranges from at least 200, or at least 300, or at least 400, or at least 500, or at least 600, and up to 40,000, or up to 20,000, or up to 15,000, or up to 10,000, or up to 7500, or up to 5000, or up to 1500, or up to 1200, or up to 1000. Examples of yellow colorants having a molecular weight within a range of 600 to 1000 include CI Pigment Yellow 16, 81, 93, 94, 95, 113, 124, 168, 169, and 180.
A reactive colorant has at least one polyester reactive group. A polyester reactive group is a functional group reactive with one or more of the monomers or reactants used to make a polyester polymer, or reactive with a polyester polymer itself, and is reactive under melt processing conditions used to make an article or under melt phase conditions for the manufacture of a polyester polymer. The colorants can be added to a melt processing zone for making the article and reacted with the polyester polymer in the melt processing zone, or added to a melt phase polymerization process for making the polyester polymer and reacted with the reaction mixture in the melt phase, to thereby reduce the extractability of the colorants from the polymer relative to the colorants that are substantially non-reactive. In this embodiment, the colorant is also preferably thermally stable during melt phase polymerization or in a melt processing zone for making an article.
Non-extractable yellow reactive colorants are described in U.S. Pat. Nos. 4,359,570, 4,617,373; 5,106,942; the entire disclosures of which are incorporated herein by reference.
One example of non-extractable yellow, orange, and red reactive colorants described in U.S. Pat. Nos. 4,617,373 and 5,106,942 has at least one methine moiety defined herein as the group:
conjoined with a conjugated aromatic or heteroaromatic system. This moiety imparts the property of ultraviolet and/or visible light absorption, generally within the range of about 350-650 nanometers (nm). The position of the maximum of absorption is determined by the choice of substituents on the methine group. This structure class provides a very useful class of yellow dyes which absorbs strongly in the uv/visible part of the spectrum of wavelengths of the range 330 nm to 470 nm depending upon the substituents present on the chromophore. The methine compounds usually have a number average molecular weight of from about 200 to about 600, although lesser and higher molecular weights are useful. These yellow colorants have at least one polyester reactive group which will react with at least one of the functional groups from which the polyester is prepared into the polymer chain. Such polyester reactive groups are selected from hydroxyl, carboxy, amino C1-C6-alkoxycarbonyl, C1-C6-alkoxycarbonyloxy, and C1-C6-alkanoyloxy. These light-absorbing compounds are thermally stable at polymer processing temperatures up to about 300° C.
Preferred methine light absorbing compounds or monomers useful in the practice of the present invention have the general formulae:
wherein:
A is conjugated with the attached double bond and is selected from the group of nitrogen containing moieties having the following formulae:
R and R′ are independently selected from hydrogen, C1-C6-alkyl, C1-C6-alkoxy and halogen;
n is 1 or 2;
R1 is selected from C3-C8-cycloalkyl, C3-C8-alkenyl, aryl, C1-C12-alkyl, substituted C1-C12-alkyl, and —(CHR13 CHR14O)m—R15, wherein: m is an integer from 1 to about 500, preferably from 1 to about 100, more preferably from 1 to 8, and most preferably from 1 to 3; and
R2 is selected from C3-C8-Cycloalkyl, C3-C8-alkenyl, aryl, C1-C12-alkyl, substituted C1-C12-alkyl, —(CHR13 CHR14O)m—R15, and an acyl group selected from —COR16, —CO2R16, —CONHR16— and —SO2R16, with the provision that when R2 is an acyl group R1 may be hydrogen; or
R1 and R2 can be combined with the nitrogen atom to which they are attached to make cyclic structures selected from pyrrolidino, piperidino, piperazino, morpholino, thiomorpholino, thiomorpholino-S,S-dioxide, succinimido, and phthalimido;
R3 is selected from C2-C6-alkylene, and —(CHR13CHR14O)m—CHR13CHR14—;
R4, R5 and R6 are independently selected from hydrogen and C1-C6-alkyl;
R7 is selected from hydrogen, C1-C6-alkyl and aryl;
R8 and R9 are independently selected from C1-C12-alkyl, substituted C1-C12-alkyl, aryl, C3-C8-cycloalkyl, and C3-C8-alkenyl or R8 and R9 can be combined with the nitrogen atom to which they are attached to produce cyclic structures such as pyrrolidino, piperidino and morpholino;
R10 and R11 are independently selected from hydrogen, halogen, C1-C6-akyl, hydroxyl and C1-C6-alkanoyloxy;
R12 is carboxy, C1-C6-alkoxycarbonyl or (R)n;
R13 and R14 are independently selected from hydrogen and C1-C6-alkyl;
R15 is selected from hydrogen, aryl, C1-C12-alkyl, and C1-C6-alkanoyloxy;
R16 is selected from C1-C6-alkyl, C3-C8-alkenyl, aryl, and C3-C8-cycloalkyl;
X is selected from —O—, —NH and —N(R16)—;
L is a di, tri or tetravalent linking group;
L1 is selected from a direct single bond or a divalent linking group;
P and Q are independently selected from cyano, —COR16, —CO2R16, —CON(R17)R18, aryl, heteroaryl, and —SO2R16; or
P and Q can be combined with the conjugated double-bonded carbon atom to which they are attached to produce the following cyclic divalent radicals:
R17 and R18 are independently selected from hydrogen, C1-C6-alkyl, aryl C3-C8-cycloalkyl, and C3-C8-alkenyl;
R19 is selected from cyano, carboxy, —CO2R16, —CON(R17)R18 and
R20 is selected from aryl and heteroaryl;
X2 is selected from —O—, —S—, —N(R17)—;
R21 is selected from hydrogen, or up to two groups selected from C1-C6-alkyl, C1-C6-alkoxy, halogen, carboxy, cyano and —CO2R16; with the provision that Q may be hydrogen when P is selected from -carboxy, —CO2R16, —C(R20)═C(CN)CN and
The methine compounds may have at least one reactive group selected from carboxy, —CO2R16, —OCOR16, —OCON(R17)R18, —OCO2R16, hydroxyl and chlorocarbonyl, that is capable of reacting into the polyester composition during preparation or during melt phase processing to make an article.
In another embodiment, suitable yellow methine polymeric colorants have structures I (U.S. Pat. No. 5,254,625) and II (U.S. Pat. No. 5,532,332), both of which are fully incorporated herein by reference:
wherein:
in structure II
Yellow polymeric anthraquinone colorants (U.S. Pat. No. 6,197,223; Weaver, et al, “Coloration Technology”, 119, 48-56 (2003) which are suitable in the practice of the invention have structures III and IV:
wherein:
Two of the preferred structures for III and IV are IIIa and IVa, respectively:
A “C1-C12-alkyl” may contain one to twelve carbon atoms and is either a straight or branched chain.
A “substituted C1-C12-alkyl” may be substituted with 1-3 groups selected from halogen, hydroxyl, cyano, carboxy, succinimido, phthalimido, 2-pyrrolidino, C3-C8-cycloalkyl, aryl, heteroaryl, vinylsulfonyl, phthalimidino, o-benzoic sulfimido, —OR33, —SR34, —SO2R35, —SO2CH2CO2SR34, —CON(R36)R37, —SO2N(R36)R37, —O2CN(R36)R37, —OCOR35, —O2CR35, —OCO2R35, —OCR35, —N(R25)SO2R35, —N(R25)COR35,
wherein:
A “C1-C6-alkyl” is a straight and branched chain hydrocarbon radicals, which may optionally be substituted with up to two groups selected from hydroxyl, halogen, carboxy, cyano, aryl, arylthio, arylsulfonyl, C1-C6-alkoxy, C1-C6-alkylthio, C1-C6-alkylsulfonyl, C1-C6-alkoxycarobonyl, C1-C6-alkoxycarbonyloxy, and C1-C6-alkanoyloxy.
A “C1-C6-alkoxy”, “C1-C6-alkylthio”, “C1-C6-alkylsulfonyl”, “C1-C6-alkoxycarbonyl”, “C1-C6-alkoxycarbonyloxy” and “C1-C6-alkanoyloxy” may have the following structures, respectively: —OC1—C6-akyl, —S—C1-C6-alkyl, —O2S—C1-C6-alkyl, —CO2-C1-C6-alkyl, —O2C—O-C1-C6-alkyl, and —O2C—C1-C6-alkyl, wherein the C1-C6-alkyl groups may optionally be substituted with up to two groups selected from hydroxy, cyano, halogen, aryl, —OC1-C4-alkyl, —OCOC1-C4-alkyl and CO2C1-C4-alkyl, wherein the C1-C4-alkyl portion of the group represents saturated straight or branched chain hydrocarbon radicals that contain one to four carbon atoms.
A “C3-C8-cycloalkyl” and “C3-C8-alkenyl” includes a saturated cycloaliphatic radicals and straight or branched chain hydrocarbon radicals containing at least one carbon-carbon double bond, respectively, with each radical containing 3-8 carbon atoms.
The divalent linking groups for L can be selected from C1-C12-alkylene, —(CHR13CHR14O)mCHR13CHR14—, C3-C8-cycloalkylene, —CH2—C3-C8-cycloalkylene —CH2— and C3-C8-alkenylene. The C1-C12 alkylene linking groups may contain within their main chain heteroatoms, e.g. oxygen, sulfur and nitrogen and substituted nitrogen, (—N(R17)—), wherein R17 is as previously defined, and/or cyclic groups such as C3-C8-cycloalkylene, arylene, divalent heteroaromatic groups or ester groups such as:
Some of the cyclic moieties which may be incorporated into the C1-C12-alkylene chain of atoms include:
The trivalent and tetravalent radicals for L are selected from C3-C8-aliphatic hydrocarbon moieties which contain three or four covalent bonds.
Examples of trivalent and tetravalent radicals include —HC(CH2—)2 and C(CH2—)4, respectively.
The divalent linking groups for L1 may be selected from —O—, —S—, —SO2—, ═N—SO2R1, —S—S—, —CO2—, —OCO2—, arylene, —O-arylene-O—, C3-C8-cycloalkylene, —O2C—C1-C12-alkylene-CO2—, —O2C-arylene-CO2—, —O2C—C3C8-cycloalkylene-CO2—, —O2CNH—C1-C12-alkylene-NHCO2—, and —O2CNH-arylene-NHCO2—.
A “C2-C4-alkylene”, “C1-C6-alkylene” and “C1-C12-alkylene” includes a straight or branded chain divalent hydrocarbon radicals containing two to four, one to six and one to twelve carbon atoms, respectively, which may optionally may be substituted with up to two groups selected from hydroxyl, halogen, aryl and C1-C6-alkanoyloxy.
A “C3-C8-cycloalkylene” and C3-C8-alkylene” includes a divalent saturated cyclic hydrocarbon radicals which contain three to eight carbon atoms and divalent hydrocarbon radicals which contain at least one carbon-carbon double bond and have three to eight carbon atoms, respectively.
An “aryl” is a phenyl and phenyl substituted with one or more groups selected from C1-C6-alkyl, C1-C6-alkoxy, halogen, carboxy, hydroxyl, C1-C6-alkoxycarbonyl, C1-C6-alkylsulfonyl, C1-C6-alkythio, thiocyano, cyano, nitro and trifluoromethyl.
In the term “heteroaryl” the heteroaryl groups or heteroaryl portions of the groups are mono or bicyclo heteroaromatic radicals containing at least one heteroatom selected from the group consisting of oxygen, sulfur and nitrogen or a combination of these atoms in combination with carbon to complete through the heteroatomatic ring. Examples of suitable heteroaryl groups include but are not limited to: furyl, thienyl, thiazolyl, isothiazolyl, benzothiazolyl, pyrazolyl, pyrrolyl, thiadiazolyl, oxadiazolyl, benzoxazolyl, benzimidazolyl, pyridyl, pyrimidinyl and triazolyl and such groups optionally substituted with one or more groups selected from C1-C6-alkyl, C1-C6-alkoxy, aryl, C1-C6-alkoxy, carbonyl, halogen, arylthio, arylsulfonyl, C1-C6-alkylthio, C1-C6-alkylsulfonyl, cyano, trifluoromethyl, and nitro.
An “arylene” includes a 1,2-; 1,3-; 1,4-phenylene, naphthyl and those radicals optionally substituted with one or more groups selected from C1-C6-alkyl, C1-C6-alkoxy, halogen, carboxy, hydroxyl, C1-C6-alkoxycarbonyl, C1-C6-alkylsulfonyl, C1-C6-alkythio, thiocyano, cyano, nitro and trifluoromethyl.
The term halogen is used to denote fluorine, chlorine, bromine and iodine.
The alkoxylated moieties defined by the formulae: —(CHR13CHR14O)m—R15, and —(CHR13CHR14O)m—CHR13CHR14—, have a chain length wherein m is from 1 to 500; preferably m is from 1 to about 100; more preferably m is less than 8, and most preferably m is from 1-3. In a preferred embodiment, the alkoxylated moieties are ethylene oxide residues, propylene oxide residues or residues of both.
The terms “pyrrolidino”, “piperidino”, “piperazino”, “morpholino”, “thiomorpholino” and “thiomorpholino-s,s-dioxide” are used herein to denote the following cyclic radicals, respectively:
wherein R1 is as defined above.
The skilled artisan will understand that each of the references herein to groups or moieties having a stated range of carbon atoms such as C1-C4-alkyl, C1-C6-alkyl, C1-C12-alkyl, C3-C8-cycloalkyl, C3-C8-alkenyl, C1-C12-alkylene, C1-C6-alkylene, includes moieties of all of the number of carbon atoms mentioned within the ranges. For example, the term “C1-C6-alkyl” includes not only the C1 group (methyl) and C6 group (hexyl) end points, but also each of the corresponding C2, C3, C4, and C5 groups including their isomers. In addition, it will be understood that each of the individual points within a stated range of carbon atoms may be further combined to describe subranges that are inherently within the stated overall range. For example, the term “C3-C8-cycloalkyl” includes not only the individual cyclic moieties C3 through C8, but also contemplates subranges such as C4-C6-cycloalkyl.
Specific examples of reactive methine group containing yellow colorants are:
wherein (R)n represents a —CH3 group at the 3 position; R1 and R2 are each
The dye of Example 171 can be prepared by the procedure used in Example 7 of U.S. Pat. No. 3,917,604.
Specific examples of yellow anthraquinone dyes include:
Example 172: 1,5-bis(2-carboxyphenylthio)anthraquinone, prepared as in
Example 1 of U.S. Pat. No. 4,359,570; and
Example 173: 1,5-bis[[1-(2-hydroxyethyl)-1,2,4-triazol-3-yl]thio]anthraquinone, prepared as in Example 18a of U.S. Pat. No. 6,727,372, and structures IIIa and Iva mentioned above.
In one aspect of the invention, there is provided a process for adding a yellow colorant to a melt phase polymerization process, or to the melt in a melt processing zone for making articles such as bottle preforms.
The amount of yellow colorant added is effective to produce a polyester polymer composition, preform, or bottle having a b* ranging from −5 to +5, or −4 or more, or −3 or more, or −2 or more, or −1 or more, and up to +5, or up to +4, or up to +3, or up to +2, or up to +1, and preferably between −1 and +2, or 0 and +1. The amount added desirably shifts the b* color of the polymer composition, preform, or bottle by at least 1 unit, or at least 2 units, or at least 3 units, or at least 4 units, or at least 5 units, on the b* color scale, relative to the same polymer, preform, or bottle, respectively, without the yellow colorant.
Suitable amounts of yellow colorant loading in the polymer vary widely depending on the molecular weight of the colorant, but generally not more than 100 ppm yellow colorant is required. In one aspect of the invention, the yellow colorant loading in the polyester polymer composition, particles, preforms, and/or bottles is typically 15 ppm or less, or 10 ppm or less, or 7 ppm or less, or 5 ppm or less, or 3 ppm or less, or 2 ppm or less, or 1 ppm or less, and greater than 0, based on the weight of the polyester polymer composition, particle, preform, and/or bottle.
In another embodiment of the invention, the polyester polymer composition contains orange and/or red colorants in addition to yellow colorants. The orange and/or red colorants may be added to a melt phase polymerization process or compounded with a polyester polymer in an extruder or added to an injection molding machine along with a polyester polymer for making a preform or other article.
Orange colorants are colorants that are orange to the eye. These colorants desirably absorb light in the visible light spectrum at wavelengths within the range of 475 nm to 490 nm. In one embodiment, the λmax falls within the range of 475 nm to 490 nm. The amount of orange colorant in the polymer is desirably 15 ppm or less, or 10 ppm or less, or 7 ppm or less, or 5 ppm or less, or 3 ppm or less, or 2 ppm or less, or 1 ppm or less, and greater than 0, based on the weight of the polyester polymer composition, particle, preform, and/or bottle. In another embodiment, the amount of orange colorant is effective to provide, together with the yellow colorant, a polyester polymer, preform, and/or bottle having a b* in the range of −2 to 4, and an a* in the range of −3 to 2
Examples of orange colorants for mixing with the yellow colorants as desired are: C. I. Solvent Oranges 60, 107, 109, 111, and 113; as well as C. I. Pigment Oranges 43 and 77. Useful thermally stable orange colorants which may be added during melt processing for copolymerization or by admixing into the polyester have structure V (U.S. Pat. No. 4,745,173, fully incorporated herein by reference);
wherein
Red colorants are colorants that are red to the eye. These colorants desirably absorb light in the visible light spectrum at wavelengths within the range of 490 to 530 nm. In one embodiment, the λmax falls within the range of 490 nm to 530 nm. The amount of red colorant in the polymer is desirably 15 ppm or less, or 10 ppm or less, or 7 ppm or less, or 5 ppm or less, or 3 ppm or less, or 2 ppm or less, or 1 ppm or less, and greater than 0, based on the weight of the polyester polymer composition, particle, preform, and/or bottle. In another embodiment, the amount of red colorant is effective to provide, together with the yellow colorant, a polyester polymer, preform, and/or bottle having a b* in the range of −2 to 4, and an a* in the range of −3 to 2.
Examples of red colorants for mixing with the yellow colorants to obtain the desired hue include C. I Solvent Reds 52, 135, 149, 151, 179, and 235; as well as C. I. Pigment Reds 149, 168, and 194. Useful thermally stable reactive colorants suitable for mixing with the yellow colorants and which are capable of being copolymerized when added during the melt phase polymerization process are disclosed in U.S. Pat. No. 5,372,864, fully incorporated herein by reference. Useful red anthraquinone colorants are described in structures II-VI in columns 3-6 and useful anthrapyridone colorants are described by structures VII-X in columns 5-8 of that patent. These red colorants are also useful for admixing with polyesters by compounding and melt blending or when added to a melt processing zone in the polyester preparation. Tables 2-10 of U.S. Pat. No. 5,372,864, fully incorporated herein by reference, disclose numerous specific examples of useful red colorants.
Thus, one may combine a yellow colorant with an orange colorant to obtain the desired hue. One may alternatively combine a yellow colorant with a red colorant to obtain the desired hue. Or, one many combine a yellow colorant, red colorant and an orange colorant. The particular combination of colorants and the amount of each added will depend on the desired color.
There is also provided another embodiment comprising a process for making a molded article comprising combining in a melt processing zone a yellow colorant composition and solid polyester polymer particles containing reheat agent particles comprising titanium, alloys of titanium, titanium nitride, titanium boride, titanium carbide, or combinations thereof to produce a colored molten composition, and molding the molten composition into an article, such as a preform, bottle, or other article. The article can be formed by extrusion, injection molding, or extrusion blow molding. Bottle preforms can be stretch blow molded into beverage containers, such as water, carbonated soft drink, or hot fill bottles.
As noted above, the colorant may be added to a melt phase polymerization process or to a melt processing zone fed by polyester polymer particles for making articles. The colorant may be fed in either case as a liquid or solid or a melt.
In a melt phase polymerization zone, polyester polymer compositions are made from reactants. The colorant may be added to the esterification zone, polycondensation zone (either to prepolymerization or to the finishing zone, or to conduits feeding any reactor or heat exchanger within the melt phase polymerization process. It may be injected neat, in a solution, dispersion, as a paste, or in a molten concentrate. It may be added to the melt phase polymerization process alone or together in combination with other additives, such as the catalyst, UV inhibitor, or reheat agents.
Suitable polymers made in the melt phase polymerization process are polyester polymers which are thermoplastic polymers. Thermoplastic polymers as used herein are distinguishable from thermotropic liquid crystals. Examples of suitable polyester polymers include one or more of: polyethylene terephthalate polymers (PET), polyethylene naphthalate polymers (PEN), poly(1,4-cyclo-hexylenedimethylene) terephthalate polymers and copolymers (PCT), poly(ethylene-co-1,4-cyclohexylenedimethylene terephthalate) polymers (PETG), copoly(1,4-cyclohexylene dimethylene/ethylene terephthalate) (PCTG), poly(1,4-cyclohexylene dimethylene terephthalate-co-isophthalate) (PCTA), poly(ethylene terephthalate-co-isophthalate) (PETA) and their blends, combinations thereof, or their copolymers. The form of a polyester composition is not limited, and includes a melt in the manufacturing process or in the molten state after polymerization, such as may be found in an injection molding machine, and in the form of a liquid, pellets, preforms, and/or bottles. Polyester particles may be isolated as a solid at 25° C. and 1 atm in order for ease of transport and processing. The shape of the polyester particles is not limited, and is typified by regular or irregular shaped discrete particles, but may be distinguished from a sheet, film, or fiber.
Examples of suitable polyesters include those described in U.S. Pat. No. 4,359,570, incorporated herein by reference in its entirety.
It should also be understood that as used herein, the term polyester is intended to include polyester derivatives, including, but not limited to, polyether esters, polyester amides, and polyetherester amides. Therefore, for simplicity, throughout the specification and claims, the terms polyester, polyether ester, polyester amide, and polyetherester amide may be used interchangeably and are typically referred to as polyester, but it is understood that the particular polyester species is dependant on the starting materials, i.e., polyester precursor reactants and/or components.
The melt phase polymerization process is useful to make polyester polymers, such as polyalkylene terephthalate or naphthalate polymers made by transesterifying a dialkyl terephthalate or dialkyl naphthalate or by directly esterifying terephthalic acid or naphthalene dicarboxylic acid. Thus, there are provided processes for making polyalkylene terephthalate or naphthalate polymer compositions by transesterifying a dialkyl terephthalate or naphthalate or directly esterifying a terephthalic acid or naphthalene dicarboxylic acid with a diol, and adding the described reheat agents and optionally the yellow colorant to the melt phase polymerization for the production of a polyalkylene terephthalate or naphthalate in the esterification zone, prepolymer zone, finishing zone, or to conduits between reactors in the melt phase polymerization process.
A preferred polyester polymer is a polyalkylene terephthalate polymer such as a polyethylene terephthalate polymer. As used herein, a polyalkylene terephthalate polymer or polyalkylene naphthalate polymer means a polymer having repeating alkylene terephthalate units or repeating alkylene naphthalate units in an amount of at least 60 mole %, or at least 70 mole %, or at least 80 mole %, or at least 90 mole %, based on the total moles of units in the polymer, respectively. Thus, the polymer may contain alkylene (e.g. ethylene) terephthalate or naphthalate units in an amount of at least 85 mole %, or at least 90 mole %, or at least 92 mole %, or at least 94 mole %, or at least 95 mole %, or at least 96 mole %, as measured by the mole % of ingredients in the finished polymer. Thus, a polyethylene terephthalate polymer may comprise a copolyester of ethylene terephthalate units and other units derived from an alkylene glycol or aryl glycol with an aliphatic or aryl dicarboxylic acid.
Polyethylene terephthalate can be manufactured by reacting a carboxylic acid component comprising a carboxylic acid or diester component comprising at least 60 mole % terephthalic acid or C1-C4 dialkylterephthalate, or at least 70 mole %, or at least 85 mole %, or at least 90 mole %, or at least 92 mole % or at least 94 mole % or at least 95 mole %, or at least 96 mole %, or at least 97 mole %, or at least 98 mole %, and a hydroxyl component comprising at least 60 mole % ethylene glycol, or at least 70 mole %, or at least 85 mole %, or at least 90 mole %, or at least 92 mole % or at least 94 mole % or at least 95 mole %, or at least 96 mole %, or at least 97 mole %, or at least 98 mole %. It is preferable that the carboxylic acid component is at least terephthalic acid and the hydroxyl component is at least ethylene glycol. The mole percentage for all the carboxylic acid component(s), preferably dicarboxylic acid components, totals 100 mole %, and the mole percentage for all the hydroxyl components, preferably the diol component(s), totals 100 mole %.
In another embodiment, the polyester polymer comprises residues of alkylene terephthalate or naphthalate residues, such as alkylene terephthalate residues (also known as repeating units) In another embodiment, the polyester polymer comprises residues of alkylene terephthalate or naphthalate residues, such as alkylene terephthalate residues, including ethylene terephthalate residues, each in an amount of at least 40 mole %, or at least 50 mole %, or at least 60 mole %, or at least 70 mole %, or at least 80 mole %, or at least 90 mole %, or at least 95 mole %, or at least 98 mole %.
In another embodiment, the polyester polymer comprises residues of alkylene terephthalate or naphthalate residues, such as alkylene terephthalate residues, including ethylene terephthalate residues, each in an amount of at least 40 mole %, or at least 50 mole %, or at least 60 mole %, or at least 70 mole %, or at least 80 mole %, or at least 90 mole %, or at least 95 mole %, or at least 98 mole %.
Examples of dicarboxylic acid units useful for the carboxylic acid component are units from phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4′-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and the like, with isophthalic acid, naphthalene-2,6-dicarboxylic acid, and cyclohexanedicarboxylic acid being preferable. It should be understood that use of the corresponding acid anhydrides, esters, and acid chlorides of these acids is included in the term “dicarboxylic acid” and all other carboxylic acid components.
In addition to units derived from ethylene glycol, the hydroxyl component of the present polyester may be modified with units from additional hydroxyl bearing compounds such as diols including cycloaliphatic diols preferably having 6 to 20 carbon atoms and aliphatic diols preferably having 2 to 20 carbon atoms. Examples of such diols include diethylene glycol (DEG); triethylene glycol; 1,4-cyclohexanedimethanol; 1,3-propanediol; 1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol; 3-methyl-2,4-pentanediol; 2-methyl-1,4-pentanediol; 2,2,4-trimethyl-1,3-pentanediol; 2,2-diethyl-1,3-propanediol; 1,3-hexanediol; 1,4-di-(hydroxyethoxy)-benzene; 2,2-bis-4-hydroxycyclohexyl propane; 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane; 2,2-bis-3-hydroxyethoxyphenyl propane; and 2,2-bis-4-hydroxypropoxyphenyl propane.
The polyester compositions of the invention may be prepared by conventional polymerization procedures well-known in the art sufficient to effect esterification and polycondensation. Polyester melt phase polymerization manufacturing processes include direct condensation of a dicarboxylic acid with a diol optionally in the presence of esterification catalysts in the esterification zone, followed by polycondensation in the prepolymer and finishing zones in the presence of a polycondensation catalyst; or else ester interchange usually in the presence of a transesterification catalyst in the esterification zone, followed by prepolymerization and finishing in the presence of a polycondensation catalyst, and each may optionally be subsequently solid-stated according to known methods.
The polyester polymers obtained from the melt phase polymerization have an It.V. of at least 0.50 dL/g, or at least 0.60 dL/g, and preferably at least 0.70 dL/g, or at least 0.72 dL/g, or at least 0.74 dL/g, or at least 0.76 dL/g, or at least 0.78 dL/g, or at least 0.80 dL/g.
To further illustrate the process, a mixture of one or more dicarboxylic acids, preferably aromatic dicarboxylic acids, or ester forming derivatives thereof, and one or more diols, are continuously fed to an esterification reactor operated at a temperature of between 200° C. and 300° C., typically between 240° C. and 290° C., and at a pressure of 1 psig up to 70 psig. The residence time of the reactants typically ranges from between one and five hours. Normally, the dicarboxylic acid is directly esterified with diol(s) at elevated pressure and at a temperature of 240° C. to 270° C. The esterification reaction is continued until a degree of esterification of at least 60% is achieved, but more typically until a degree of esterification of at least 85% is achieved to make the desired monomer. The esterification reaction is typically uncatalyzed in the direct esterification process and catalyzed in transesterification processes. Polycondensation catalysts may optionally be added in the esterification zone along with esterification or transesterification catalysts.
Typical esterification/transesterification and polycondensation catalysts which may be used include the oxides, hydroxides, carboxylates, alkoxides or chelates of antimony, titanium, aluminum, cobalt, germanium, zinc, tin, magnesium, manganese, and alkali metals or alkaline earth metals. Preferred catalyst metals are titanium, aluminum, and alkali metals or alkaline earth metals and range from 2 ppm to 100 ppm cumulatively, or from 2 ppm to 50 ppm cumulatively, or from 2 ppm to 25 ppm cumulatively, or from 2 ppm to 50 ppm individually, or from 2 ppm to 25 ppm individually, or from 2 ppm to less than 15 ppm individually, or from 2 ppm to 13 ppm individually, in any combination.
The resulting products formed in the esterification zone include bis(2-hydroxyethyl)terephthalate (BHET) monomer, low molecular weight oligomers, DEG, and water as the condensation by-product, along with other trace impurities formed by the reaction of the catalyst and other compounds such as colorants or the phosphorus-containing compounds. The relative amounts of BHET and oligomeric species will vary depending on whether the process is a direct esterification process, in which case the amount of oligomeric species are significant and even present as the major species, or a transesterification process, in which case the relative quantity of BHET predominates over the oligomeric species. The water is removed as the esterification reaction proceeds and excess ethylene glycol is removed to provide favorable equilibrium conditions. The esterification zone typically produces the monomer and oligomer mixture, if any, continuously in a series of one or more reactors. Alternatively, the monomer and oligomer mixture could be produced in one or more batch reactors. It is understood, however, that in a process for making PEN, the reaction mixture will contain monomeric species such as bis(2-hydroxyethyl)naphthalate and its corresponding oligomers. Once the ester monomer is made to the desired degree of esterification, it is transported from the esterification reactors in the esterification zone to the polycondensation zone comprised of a prepolymer zone and a finishing zone.
Although reference is made to a prepolymer zone and a finishing zone, it is to be understood that each zone may comprise a series of one or more distinct reaction vessels operating at different conditions, or the zones may be combined into one reaction vessel using one or more sub-stages operating at different conditions in a single reactor. That is, the prepolymer stage can involve the use of one or more reactors operated continuously, one or more batch reactors or even one or more reaction steps or sub-stages performed in a single reactor vessel. In some reactor designs, the prepolymerization zone represents the first half of polycondensation in terms of reaction time, while the finishing zone represents the second half of polycondensation. While other reactor designs may adjust the residence time between the prepolymerization zone to the finishing zone at a 2:1 ratio, a common distinction in all designs between the prepolymerization zone and the finishing zone is that the latter zone operates at a higher temperature, lower pressure, and a higher surface renewal rate than the operating conditions in the prepolymerization zone. Generally, each of the prepolymerization and the finishing zones comprise one or a series of more than one reaction vessel, and the prepolymerization and finishing reactors are sequenced in a series as part of a continuous process for the manufacture of the polyester polymer.
Once an It.V. of typically no greater than 0.35 dL/g, or no greater than 0.40 dL/g, or no greater than 0.45 dL/g, is obtained, the prepolymer is fed from the prepolymer zone to a finishing zone where the second half of polycondensation is continued in one or more finishing vessels ramped up to higher temperatures than present in the prepolymerization zone, to a value within a range of from 280° C. to 305° C. until the It.V. of the melt is increased from the It.V of the melt in the prepolymerization zone (typically 0.30 dL/g but usually not more than 0.35 dL/g) to an It.V in the range of from at least 0.50 dL/g, or at least 0.60 dL/g, or at least 0.70 dL/g, or at least 0.72 dL/g, or at least 0.74 dL/g, or at least 0.76 dL/g, or at least 0.78 dL/g, or at least 0.80 dL/g. The final vessel, generally known in the industry as the “high polymerizer,” “finisher,” or “polycondenser,” is operated at a pressure lower than used in the prepolymerization zone, typically within a range of between 0.8 torr and 4.0 torr, or from 0.5 torr to 4.0 torr. Although the finishing zone typically involves the same basic chemistry as the prepolymer zone, the fact that the size of the molecules, and thus the viscosity, differs, means that the reaction conditions also differ. However, like the prepolymer reactor, each of the finishing vessel(s) is connected to a flash vessel and each is typically agitated to facilitate the removal of ethylene glycol.
The polyester polymer particles are preferably produced from the melt phase polymerization without further polymerization in the solid phase. Alternatively, they can be further polymerized in the solid-state.
There is provided a shipping container containing polyester polymer particles having an It.V. of at least 0.70, or at least 0.72, or at least 0.74, or at least 0.76, or at least 0.78, or at least 0.80 dL/g obtained from a melt phase polymerization and/or which have not been solid state polymerized. The shipping container is a container used to transport the polyester particles to a converter of the particles to make shaped articles. Examples of shipping containers include drums, totes, railcars, ship holds, and Gaylord boxes. These polyester polymer particles which have not been solid state polymerized are also fed to a melt processing zone to make shaped articles such as preforms, a suitable melt processing zone being an injection molding machine. The volume of the polyester particles within the shipping container may be at least 1 m3, or at least 5 m3, or at least 10 m3, or at least 15 m3.
The residence time in the polycondensation vessels and the feed rate of the ethylene glycol and terephthalic acid into the esterification zone in a continuous process is determined in part based on the target molecular weight of the polyethylene terephthalate polyester. Because the molecular weight can be readily determined based on the intrinsic viscosity of the polymer melt, the intrinsic viscosity of the polymer melt is generally used to determine polymerization conditions, such as temperature, pressure, the feed rate of the reactants, and the residence time within the polycondensation vessels.
Once the desired It.V. is obtained in the finisher, the melt is fed to a pelletization zone where it is filtered and extruded into the desired form. The polyester polymers of the present invention are filtered to remove particulates over a designated size, followed by extrusion in the melt phase polymerization to form polymer sheets, filaments, or pellets. Although this zone is termed a “pelletization zone”, it is understood that this zone is not limited to solidifying the melt into the shape of pellets, but includes solidification into any desired shape. Preferably, the polymer melt is extruded immediately after polycondensation. After extrusion, the polymers are quenched, preferably by spraying with water or immersing in a water trough, to promote solidification. The solidified condensation polymers are cut into any desired shape, including pellets.
Alternatively, once the polyester polymer is manufactured in the melt phase polymerization, it may be solidified. The method for solidifying the polyester polymer from the melt phase polymerization process is not limited. For example, molten polyester polymer from the melt phase polymerization may be directed through a die, or merely cut, or both directed through a die followed by cutting the molten polymer. A gear pump may be used as the motive force to drive the molten polyester polymer through the die. Instead of using a gear pump, the molten polyester polymer may be fed into a single or twin screw extruder and extruded through a die, optionally at a temperature of 190° C. or more at the extruder nozzle. Once through the die, the polyester polymer may be drawn into strands, contacted with a cool fluid, and cut into pellets, or the polymer may be pelletized at the die head, optionally underwater. The polyester polymer melt optionally filtered to remove particulates over a designated size before being cut. Any conventional hot pelletization or dicing method and apparatus can be used, including but not limited to dicing, strand pelletizing and strand (forced conveyance) pelletizing, pastillators, water ring pelletizers, hot face pelletizers, underwater pelletizers, and centrifuged pelletizers.
The polyester polymer of the invention may be partially crystallized to produce semi-crystalline particles. The method and apparatus used to crystallize the polyester polymer is not limited, and includes thermal crystallization in a gas or liquid. The crystallization may occur in a mechanically agitated vessel; a fluidized bed; a bed agitated by fluid movement; an un-agitated vessel or pipe; crystallized in a liquid medium above the glass transition temperature (Tg) of the polyester polymer, preferably at 140° C. to 190° C.; or any other means known in the art. Also, the polymer may be strain crystallized. The polymer may also be fed to a crystallizer at a polymer temperature below its Tg (from the glass), or it may be fed to a crystallizer at a polymer temperature above its Tg. For example, molten polymer from the melt phase polymerization reactor may be fed through a die plate and cut underwater, and then immediately fed to an underwater thermal crystallization reactor where the polymer is crystallized underwater. Alternatively, the molten polymer may be cut, allowed to cool to below its Tg, and then fed to an underwater thermal crystallization apparatus or any other suitable crystallization apparatus. Or, the molten polymer may be cut in any conventional manner, allowed to cool to below its Tg, optionally stored, and then crystallized. Optionally, the crystallized polyester may be solid stated according to known methods.
The particles desirably have a degree of crystallinity of at least 25%, or at least 30%, or at least 35%, or at least 40%, or at least 45%, and up to about 70%, or up to about 65%.
As known to those of ordinary skill in the art, the pellets formed from the condensation polymers, in some circumstances, may be subjected to a solid-stating zone wherein the solids are first crystallized followed by solid-state polymerization (SSP) to further increase the It.V. of the polyester composition solids from the It.V exiting the melt phase polymerization to the desired It.V. useful for the intended end use. Typically, the It.V. of solid stated polyester solids ranges from 0.70 dL/g to 1.15 dL/g. In a typical SSP process, the crystallized pellets are subjected to a countercurrent flow of nitrogen gas heated to 180° C. to 220° C., over a period of time as needed to increase the It.V. to the desired target.
Thereafter, polyester polymer solids, whether solid stated or not, are re-melted and re-extruded to form items such as containers (e.g., beverage bottles), filaments, films, or other applications. At this stage, the pellets are typically fed into an injection molding machine suitable for making preforms which are stretch blow molded into bottles.
If the reheat agent particles are added to the melt phase polymerization, it is desirable to use particles having a small enough particle size to pass through the filters in the melt phase polymerization, and in particular the pelletization zone. In this way, the particles will not clog up the filters as seen by an increase in gear pump pressure needed to drive the melt through the filters. However, if desired, the reheat agent particles can be added after the pelletization zone filter and before or to the extruder of the injection molding machine.
The reheat agent particles may also be added to post-consumer recycle (PCR) polymer. PCR containing reheat agent particles may be added to virgin bulk polymers by solid/solid blending or by feeding both solids to an extruder. Alternatively, PCR polymers containing the reheat agent particles are advantageously added to the melt phase polymerization for making virgin polymer between the prepolymerization zone and the finishing zone. The It.V. of the virgin melt phase polymerization after the prepolymerization zone is sufficiently high at that point to enable the PCR to be melt blended with the virgin melt. Alternatively, PCR may be added to the finisher. In either case, the PCR added to the virgin melt phase polymerization may contain the reheat agent particles. The reheat agent particles may be combined with PCR by any of the methods noted above, or separately fed to and melt blended in a heated vessel, followed by addition of the PCR melt containing the reheat agent particles to the virgin melt phase polymerization at these addition points.
Examples of other reheat rate enhancing additives that may be used in combination with reheat agent particles include carbon black, graphite, tungsten, molybdenum, antimony, tin, copper, silver, gold, palladium, platinum, black iron oxide, and the like, in the amounts and sizes described above with respect to the reheat agent particles of the invention, as well as near infrared absorbing dyes, including, but not limited to, those disclosed in U.S. Pat. No. 6,197,851, incorporated herein by reference.
The compositions of the present invention optionally may contain one or more additional UV-absorbing compounds. One example includes UV-absorbing compounds which are covalently bound to the polyester molecule as either a comonomer, a side group, or an end group. Suitable UV-absorbing compounds are thermally stable at polyester processing temperatures, absorb in the range of from 320 nm to 380 nm, and migrate minimally from the polymer. The UV-absorbing compounds preferably provide less than 20%, more preferably less than 10%, transmittance of UV light having a wavelength of 370 nm through a bottle wall or sample that is 0.012 inches thick. Suitable chemically reactive UV absorbing compounds may include, for example, substituted methine compounds.
Suitable compounds, their methods of manufacture and incorporation into polyesters include those disclosed in U.S. Pat. No. 4,617,374, the disclosure of which is incorporated herein by reference. Other suitable UV-absorbing materials include benzophenone, benzotriazole, triazine, benzoxazinone derivatives. These UV-absorbing compound(s) may be present in amounts between 1 ppm to 5,000 ppm by weight, preferably from 2 ppm to 1,500 ppm, and more preferably between 10 ppm and 1000 ppm by weight. Dimers of the UV absorbing compounds may also be used. Mixtures of two or more UV absorbing compounds may be used. Moreover, because the UV absorbing compounds are reacted with or copolymerized into the backbone of the polymer, the resulting polymers display improved processability including reduced loss of the UV absorbing compound due to plateout and/or volatilization and the like.
Hydrolytically sensitive UV absorbing compounds are preferably added, in direct esterification processes, after 50% conversion of reactants in an esterification zone, and more preferably after 95% conversion, or between esterification and polycondensation zones, or to a prepolymerization polycondensation zone. In this way, the yield (e.g. at least 40%) of the UV absorbing compound in the polyester polymer particles is increased, and the UV absorbing degradation products are reduced.
The polyester compositions of the present invention are suitable for forming a variety of shaped articles, including films, sheets, tubes, preforms, molded articles, containers and the like. Suitable processes for forming the articles are known and include extrusion, extrusion blow molding, melt casting, injection molding, stretch blow molding, thermoforming, and the like.
It is also possible to add certain diethylene glycol (DEG) inhibitors to reduce or prevent the formation of DEG in the final resin product. Preferably, a specific type of DEG inhibitor would comprise a sodium acetate-containing composition to reduce formation of DEG during the esterification and polycondensation of the applicable diol with the dicarboxylic acid or hydroxyalkyl, or hydroxyalkoxy substituted carboxylic acid. It is also possible to add stress crack inhibitors to improve stress crack resistance of bottles, or sheeting, produced from this resin.
Other components can be added to the polymer compositions of the present invention to enhance the performance properties of the polyester composition. For example, crystallization aids, impact modifiers, surface lubricants, denesting agents, stabilizers, antioxidants, ultraviolet light absorbing agents, catalyst deactivators, colorants, nucleating agents, acetaldehyde reducing compounds, other reheat enhancing aids, fillers, anti-abrasion additives, and the like can be included. The resin may also contain small amounts of branching agents such as trifunctional or tetrafunctional comonomers such as trimellitic anhydride, trimethylol propane, pyromellitic dianhydride, pentaerythritol, and other polyester forming polyacids or polyols generally known in the art. All of these additives and many others and their use are well known in the art. Any of these compounds can be used in the present composition.
As noted above, there is also provided a process for increasing the yellowness of an article, comprising adding to a melt processing zone for making said article a primary feed of polyester polymer particles and:
The primary feed of polyester polymer particles means the feed of the bulk polyester particles. A secondary feed of polyester polymer particles means a feed of polyester particles in smaller quantities by weight than the bulk polyester particles. An example of a secondary feed of polyester particles includes a feed of concentrate containing additives such as reheat agents, colorants, or other additives which one may find desirable to let down into the primary feed of polyester particles in addition to the additives already contained in the polyester particles used in the primary feed. The primary feed of polyester polymer particles is not limited to the feed into the barrel of a melt processing zone. For example, a primary and secondary feed of polyester polymer particles may be dry blended and fed together as one stream into the barrel where the polymer is melted.
In one embodiment, the reheat agent particles are contained in the polyester polymer particles. In another embodiment, the yellow colorant and optional orange and/or red colorants are contained in the polyester polymer particles. In yet another embodiment, both the reheat agent particles and the yellow colorant and optional orange and/or red colorants are contained in the polyester polymer particles.
In yet a further embodiment, the polyester polymer particles fed to the melt processing zone contain no or less than the amount of either or both of the reheat agent particles or yellow colorant than present in the article. In this case, there is provided, a feed of reheat agent particles and a feed of polyester polymer particles to the melt processing zone. In another case, there is provided a feed of yellow colorant and polyester polymer particles to the melt processing zone. In yet another case, there is provided a feed of polyester polymer particles and separate or combined feeds of yellow colorant and reheat agent particles to the melt processing zone for making the article. If feeds of yellow colorant and/or reheat agent particles to the melt processing zone are required, these streams may be fed as described above, e.g. solid concentrates let down at a desired ratio, liquid feeds as solutions, dispersions, emulsions, or pastes, or neat. Orange and/or red colorants may be combined and added or employed along with the yellow colorant as an additive to the polyester polymer or within the polyester polymer particles.
In another embodiment of the invention, there is provided concentrate particles, said particles comprising a polyester polymer, a yellow colorant, and the reheat agent particles. The concentrate differs from the polyester polymer particles described above in that the concentrate has a high concentration of yellow colorant, reheat agent particles, or both. Thus, in one embodiment, the concentrate contains a yellow colorant and reheat agent particles each or individually in an amount of at least 10 ppm, or at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 500 ppm or at least 750 ppm, or at least 1000 ppm, or at least 2000 ppm, or at least 5000 ppm, or at least 7000 ppm, or at least 10,000 ppm, or at least 12,000 ppm, or at least 15,000 ppm, or at least 20,000 ppm, and up to about 30 wt. %, or up to 20 wt. %, or up to 10 wt. %, or up to 5 wt. %, based on the weight of the concentrate. The concentrate is a useful means for incorporating the yellow colorant and reheat agent particles into the melt processing zone for mixing with the molten polyester polymer particles in the melt processing zone when making an article. Desirably, the It.V. of the polyester polymer in the solid concentrate is within ±0.10, or ±0.05, or ±0.03 It.V. of the polyester polymer particles fed to the melt processing zone. Orange and/or red colorants may be combined and added or employed along with the yellow colorant as an additive to the polyester polymer or within the concentrate.
A variety of articles can be made from the polyester compositions of the invention, including those in which reheat is neither necessary nor desirable. Articles include sheet, film, bottle preforms, bottles, trays, other packaging, rods, tubes, lids, fibers and injection molded articles. Any type of bottle can be made from the polyester compositions of the invention. Thus, in one embodiment, there is provided a beverage bottle made from PET suitable for holding water, preferably still water (non-gased). In another embodiment, there is provided a heat-set beverage bottle suitable for holding beverages which are hot-filled into the bottle. In yet another embodiment, the bottle is suitable for holding carbonated soft drinks. Further, in yet another embodiment, the bottle is suitable for holding alcoholic beverages, such as beer.
In each of the embodiments of the invention, including process for making a polyester polymer, there is also provided the polyester polymer compositions, articles including the food and beverage containers, and bottle preforms, having the properties of the polyester polymer compositions described herein.
In this example, the effect of addition of a yellow colorant to a PET polymerization process was evaluated. Two polymers were prepared. The control polymer contained titanium nitride reheat additive and red toner. The titanium nitride particles had a nominal average particle size of 20 nm and were purchased from Hefei Kiln. The red toner used was the anthraquinone colorant disclosed in Example 21 of U.S. Pat. No. 5,384,377: I,5-bis(5-(N-(2-hydroxyethyl)-N-ethylsulfamoyl)-2-methoxyanilino)anthraquinone. (CAS# 163485-98-1). The test polymer contained the same titanium nitride reheat additive, the same red toner and Yellow Colorant 1.
Yellow Colorant 1 has the structure:
wherein (R)n represents a —CH3 group at the 3 position; R1 and R2 are each
The polymers were molded into discs with a diameter of 3 cm and a thickness of 0.17 cm using a Daca MicroCompounder/MicroInjector. A HunterLab Ultrascan spectrophotometer was used to measure L*, a* and b* on the discs. The CIELAB color was calculated using D65 illuminant and 10° observer. The color measurements were made in the total transmission (TTRAN) mode. Three discs were stacked together (0.51 cm total thickness) and placed in a holder at the sphere port. The results are given in Table 1 and demonstrate the effectiveness of adding a yellow colorant to increase the yellowness of polymers containing titanium nitride reheat additive. The b* was increased from 0.29 to 1.09 by the addition of 0.36 ppm Yellow Colorant 1
This example demonstrates the effectiveness of yellow colorants to decrease the blueness of a resin containing titanium nitride using a blending method. A PET concentrate was prepared from Yellow Colorant 1, Yellow Colorant 2, and Yellow Colorant 3. The structure of Yellow Colorant 1 is described above. Yellow Colorant 2 is ethyl [[4-(dimethylamino)phenyl]methylene]propenedioate (CAS# 3435-56-1). Yellow Colorant 3 is 1,5-bis(2-carboxyphenylthio)anthraquinone (CAS # 76404-13-2).
The PET resin used to prepare the yellow colorant concentrate was Eastman PET CM01, which is commercially available from Eastman Chemical Company. The concentrates were prepared by combining the yellow colorant with CM01 resin and then extruding the mixture at 275° C. on a Daca MicroCompounder. The extrudate was cryogenically ground in a Wiley Mill to form a coarse powder. The nominal amounts of yellow colorant in each of the concentrates were the following:
Concentrate 1: 0.0025 wt % Yellow Colorant 1
Concentrate 2: 0.025 wt % Yellow Colorant 2
Concentrate 3: 0.0025 wt % Yellow Colorant 3
The effect of each yellow colorant on PET resin color was determined by blending the concentrate with a production grade PET resin (“Resin A”) containing 6 ppm Ti as nanosized titanium nitride (20 nm nominal particle size) and 1.2 ppm red toner. The red toner used was the anthraquinone colorant disclosed in Example 21 of U.S. Pat. No. 5,384,377: I,5-bis(5-(N-(2-hydroxyethyl)-N-ethylsulfamoyl)-2-methoxyanilino)anthraquinone (CAS# 163485-98-1) The titanium nitride particles in Resin A functioned to increase the reheat rate of the polymer and also caused a blue color shift in the polymer. The yellow colorant concentrates were combined with coarse granules of Resin A and dried at 110° C. in a vacuum oven for 16 hours. The dried mixtures were then extruded at 275° C. in a Daca MicroCompounder. The extrudate was ground in a Wiley Mill to produce coarse granules. The granules were then dried at 110° C. in a vacuum oven for 16 hours and were then molded into discs with a diameter of 3 cm and a thickness of 0.17 cm using a Daca MicroCompounder/MicroInjector. A HunterLab Ultrascan spectrophotometer was used to measure L*, a* and b* on the disc. The CIELAB color was calculated using D65 illuminant and 10° observer. The color measurements were made in the total transmission (TTRAN) mode, in which both light transmitted directly through the sample and the light that is diffusely scattered was measured. A single disc was placed at the sphere port. The results are given in Table 2.
The results in Table 2 show that each of the colorants is effective at decreasing the blueness of PET Resin A. Yellow Colorant 1 is the most efficient at decreasing blueness. Yellow Colorant 3 has the smallest impact on a* (i.e. less shift toward green or more negative a* value), and therefore may be preferred in certain formulations where less greenness is desired. Advantageously, all three yellow colorants caused no decrease in L* (i.e. brightness).
This example demonstrates the effectiveness of polymeric yellow colorants to decrease the blueness of a resin containing titanium nitride. Yellow Colorant 4 is a methine type polymeric colorant and has the following structure:
Yellow Colorant 5 is an anthraquinone type polymeric colorant and has the following structure:
Yellow Colorant 4 and Yellow Colorant 5 are disclosed in Coloration Technology, (2003), 119(1), pp 48-56, by Weaver, et. al.
Concentrates of the polymeric yellow colorants were prepared in Eastman PET CM01 as described in Example 2. The nominal amounts of polymeric yellow colorant in each of the concentrates were the following:
Concentrate 4: 0.0025 wt % Polymeric Yellow Colorant 4
Concentrate 5: 0.015 wt % Polymeric Yellow Colorant 5
The effect of each polymeric yellow colorant on PET resin color was determined by blending the concentrate with production grade PET Resin A, using the method described in Example 2. The results are given in Table 3.
The results in Table 3 show that the polymeric yellow colorants were effective at decreasing the blueness of PET Resin A which contains titanium nitride reheat particles. Advantageously, neither of the polymeric yellow colorants caused any decrease in L* (i.e. brightness). Of all the yellow colorants which were evaluated in Examples 2 and 3, the methine type polymeric Yellow Colorant 4 was the most efficient at decreasing blueness.
This application claims priority to Provisional Application number 60/842,253 filed on Sep. 5, 2006.
| Number | Date | Country | |
|---|---|---|---|
| 60842253 | Sep 2006 | US |
