Patent Application
20220194066
The present invention relates to multilayer barrier film structures; and more specifically, the present invention relates to improved multilayer barrier film structures that can be easily and readily identified as being recyclable or recycle-ready.
U.S. Pat. No. 10,300,686 relates that each year, a considerable amount of flexible packaging barrier film is disposed by landfill or incineration because typical functional barrier polymers such as ethylene vinyl alcohol (EVOH) or polyamide (PA) are difficult to disperse within a more conventional polyolefin (PO) waste stream for further recycling.
To reduce the amount of waste disposal of barrier film, some flexible film converters and recyclers submit post industrial waste material to a compatibility process, which is an additional separate secondary process step in the overall recycling process. In the compatibility process step, a recycling compatibilizer is added to the waste stream for further conversion of the material into pellets, allowing the pellets to be reused. However, as the above patent points out, the problem with the compatibility process step is when a post-consumer barrier film structure is collected and mixed with a conventional PO waste stream, it is very difficult to know when to use such compatibilizers and to determine the required amount of such compatibilizers to use.
U.S. Pat. No. 10,300,686 provides a solution to the above problem by producing a “self-recyclable barrier packaging” which includes a multilayer barrier film structure, in which a compatibilizer is added to the multilayer barrier film structure during production of the flexible barrier packaging film; and thus, the multilayer barrier film structure can be recycled without the barrier package having to go through the secondary compatibility process step. Accordingly, the “self-recyclable barrier packaging” disclosed in the above patent and the recycling of the barrier packaging, eliminates/avoids the secondary compatibility process step altogether.
Although U.S. Pat. No. 10,300,686 beneficially improves barrier packaging by providing a self-recyclable or recycle-ready barrier packaging without the barrier packaging having to go through a secondary compatibility process step, once the barrier packaging is mixed into a waste stream for recycling, the waste stream containing a mixture of various different packaging materials made of various polymers, it is very difficult to efficiently and easily identify the recycle-ready barrier packaging present in the mixed waste stream during the sorting and recycling process of the packaging.
Heretofore, to ensure the correct and adequate recyclability of barrier packaging, the barrier packaging is typically labeled with a standardized printed labeling system (e.g., “How2recycle label”); and the packaging must be disposed at designated drop-off recycling points. The efficient disposal and sorting of the packaging relies on: (1) the packaging (e.g., the labels), viz, how clearly does the packaging inform a consumer on how the package should be disposed of and recycled; (2) the consumer, viz, how adequate is the consumer's behavior with regard to the sorting of the packaging and the proper disposing of the packaging at the drop off recycling points; and (3). the recycling infrastructure (logistics+sorting+recycling process), viz, how capable is the infrastructure with regard to ensuring the recyclability of the material.
An examination of manual waste sorting dynamics of packaging with labels, reveals that generally labels are not necessarily observed by a sorter; but instead, the materials of a waste stream are separated by visual and tactile analyses. Also, printing removal technologies are typically used in packaging streams to remove the tracking label of a packaging; and once the tracking label of the packaging is removed, it can be lost (intentionally or accidently). And, if a packaging's composition relies on the use of a label, once the label is lost, the packaging material without a label is not distinct or distinguishable from a non-printed packaging material. Therefore, a large number of false sorting responses occur in the manual waste sorting process and recycling process.
Therefore, it is desired to further improve the multilayer barrier film structure of the self-recyclable barrier packaging disclosed in U.S. Pat. No. 10,300,686, not only by providing a novel multilayer barrier film structure that can be manufactured into a recycle-ready barrier packaging material but that can also be efficiently and easily identified during the sorting and recycling processes of the packaging, regardless of the use of a label on the packaging.
In one embodiment, the present invention is directed to a multilayer film structure which is visually identifiable as being recyclable or recycle-ready via one or more fluorescent tracers incorporated into the multilayer film structure. The terms “recycle-ready”, “ready-to-recycle”, “self-recyclable”, or “recyclable” material, can be used interchangeably herein.
In a preferred embodiment, the multi-layer film structure is a coextruded film structure for producing a recycle-ready packaging material. The multilayer coextruded film structure comprising at least two or more polymeric layers; wherein at least one of the polymeric layers comprises at least one fluorescent tracer; wherein the at least one fluorescent tracer has an absorbance wavelength and an emission wavelength when exposed to ultra violet light; wherein the at least one fluorescent tracer is invisible to the naked eye in its original state; wherein the at least one fluorescent tracer provides detectable fluorescence and becomes visible to the naked eye when the at least one fluorescent tracer is exposed to ultra violet light at an absorbance wavelength in the range of from 100 nanometers to 400 nanometers; wherein the detectable fluorescence of the at least one fluorescent tracer when exposed to ultra violet light also provides an emission wavelength in the visible spectrum range from 380 nanometers to 700 nanometers which provides visible identification of the recycle-ready packaging material made from the multi-layer film structure; and wherein the visible identification, in turn, provides the capability of sorting the recycle-ready packaging material from non-recycle-ready packaging materials.
In another preferred embodiment, the present invention is directed to a multilayer film structure such as a multilayer barrier film structure which includes at least one barrier film layer in combination with one or more polyolefin layers, such as a polyethylene layer. In the above preferred embodiment, for example, the identification of a multilayer barrier film structure as being recycle-ready is performed by incorporating a fluorescent tracer into at least one or more layers, other than the barrier layer, of the multilayer barrier film structure; and then exposing the multilayer barrier film structure to ultra violet (UV) light. With the fluorescent tracer incorporated into the body or matrix of the multilayer structure, the fluorescent tracer provides detectable fluorescence (or luminescence) and provides ease of identification of packaging material for sorting and recycling of the recycle-ready barrier packaging material without the problems of the prior art.
In another embodiment, the present invention includes a process for producing the above multilayer barrier film structure.
In still another embodiment, the present invention includes a film-forming composition for producing at least one layer of a multilayer barrier film structure; wherein the at least one layer of the multilayer barrier film structure is marked with a fluorescent tracer such that when the multilayer barrier film structure containing the fluorescent tracer is exposed to UV light, the film can be: (1) visually identified as being recyclable; and (2) separated/sorted from other different materials in a stream of mixed materials. The term “marked”, when used with reference to a multilayer film, herein means a multilayer film having a predetermined amount of an inert fluorescent tracer comprising inert particles (or particulates) incorporated in one or more layers of the multilayer film such that the fluorescent tracer is homogeneously (evenly or uniformly) dispersed in the matrix of the film.
One preferred embodiment of the above film-forming polyolefin composition comprises a mixture of: (α) at least one polyolefin polymer resin; (β) at least one fluorescent tracer; and (γ) at least one compatibilizer compound. For example, the at least one polyolefin polymer resin, component (α), can be selected from the group consisting of ethylene homopolymer, ethylene copolymer, polypropylene homopolymer, polypropylene copolymer, functionalized polyolefin polymer resin, and combinations thereof. The at least one fluorescent tracer, component (β), can include for example, derivatives of the bis-benzoxazole type such as bis-benzoxazolyl-stilbene, bis-benzoxazolyl-thiophene, and mixtures thereof. The at least one compatibilizer compound, component (γ), can comprise an anhydride, a carboxylic acid functionalized ethylene/alpha-olefin interpolymer, and combinations thereof. In a preferred embodiment, the compatibilizer has a melt viscosity at 177° C. of less than, or equal to, 200 mPa-s (200,000 cP) and a density in the range of from 0.855 g/cm3 to 0.94 g/cm3.
In another embodiment, the present invention includes a process for producing the above film-forming composition.
One of the objectives of the present invention is to provide a multilayer barrier film structure that can easily be identifiable during the sorting process and ensure the most suitable destination/recyclability.
Another objective of the present invention is to provide a multilayer barrier film structure that provides visual identification that does not rely on labeling systems or printings, in particular for improving a manual sorting process.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
Temperatures herein are in degrees Celsius (° C.).
“Room temperature” and/or “ambient temperature” herein means a temperature between 20° C. and 26° C., unless specified otherwise.
The terms “fluorescent tracer” herein means an additive that alters the visual properties of polymers; and other commonly used terms having the same meaning and that can be used interchangeably herein include “tracer”, “fluorescent material”, “fluorescent whitening agent”, “fluorescent substance”, “fluorescent tracer substance”, “fluorescent marker”, “fluorescent marker substance”, “marker” and “optical brightener”.
A “film,” or a “a multilayer film structure”, including when referring to a “film layer” in a thicker multilayer film article, unless expressly having the thickness specified, includes any thin, flat extruded or cast thermoplastic film structure article having a generally consistent and uniform thickness of about 0.5 millimeters (mm) (20 mils) or less in one dimension. The film structure can include, for example, a monolayer film, a multilayer film, a composite film product, a multi-material film product, a flexible packaging film, a coextruded multilayer multi-material film, and a coextruded multilayer mono-material film.
A “polymer film” is a film that is made of a polymer or a mixture of polymers. The composition of a polymer film is typically, 80 percent by weight (wt %) of one or more polymers.
A “multilayer film” herein means a film having two or more layers.
A “barrier film layer” herein means to film layer designed to be impervious to gas and/or liquid and prevent the migration of for example, oxygen, grease, moisture and the like. The barrier film layer can be made of barrier polymer materials such as ethylene vinyl alcohol (EVOH) or polyamide (PA).
A “tie layer”, component (II) or the second layer of the multilayer barrier film structure, herein can be any conventional tie layer used to adhere two polymeric layers together as known in the film-forming art. For example, one or more of the tie layers described, for example, in U.S. Pat. No. 10,300,686 are used in the present invention. In one preferred embodiment, the tie layer can include, for example, a polymer with a maleic anhydride (MAH)-grafted functionality, i.e., a maleic-anhydride grafted polymer such as a MAH-grafted ethylene-based polymer as described in U.S. Pat. No. 10,300,686. For example, in another embodiment, a MAH-grafted ethylene-based polymer useful in the present invention are polymers having a MAH-graft level of from 0.05 wt % to 1.20 wt %, based on the weight of the MAH-grafted polymer; and a melt index (I2) from 0.5 g/10 min to 10 g/10 min.
A “polar polymer layer” herein means a film layer comprising EVOH or PA.
“Film-forming composition” herein means a composition capable of being processed into a film article or film layer structure.
“Post-consumer recycling (PCR) materials” herein are materials/products made from recycled plastic of discarded materials from households, commercial, industrial and institutional facilities. Post-consumer waste is the world's largest waste stream. Therefore, recycle industry is constantly looking for ways to reduce the size of this waste stream. In order to produce PCR plastics, the waste stream is converted into raw materials, which makes this process a very eco-friendly solution.
The term “inert” with reference to a component material in a composition mixture herein means that the material is chemically inactive, i.e., does not react with other components in the composition; and the unreactive material maintains its original chemical structure through further processing.
A “polymer” is a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term “homopolymer” (employed to refer to polymers prepared from only one type of monomer, with the understanding that trace amounts of impurities can be incorporated into the polymer structure), and the term “interpolymer,” which includes copolymers (employed to refer to polymers prepared from two different types of monomers), terpolymers (employed to refer to polymers prepared from three different types of monomers), and polymers prepared from more than three different types of monomers. Trace amounts of impurities, for example, catalyst residues, may be incorporated into and/or within the polymer. It also embraces all forms of copolymer, e.g., random, block, and the like. It is noted that although a polymer is often referred to as being “made of” one or more specified monomers, “based on” a specified monomer or monomer type, “containing” a specified monomer content, or the like, in this context the term “monomer” is understood to be referring to the polymerized remnant of the specified monomer and not to the unpolymerized species. In general, polymers herein are referred to as being based on “units” that are the polymerized form of a corresponding monomer.
The numerical ranges disclosed herein include all values from, and including, the lower and upper value. For ranges containing explicit values (e.g., a range from 1, or 2, or 3 to 5, or 6, or 7), any subrange between any two explicit values is included (e.g., the range 1 to 7 above includes subranges 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; and the like).
The term “composition” refers to a mixture of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.
The terms “comprising,” “including,” “having,” and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term “comprising” may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term “consisting essentially of” excludes from the scope of any succeeding recitation any other component, step, or procedure, excepting those that are not essential to operability. The term “consisting of” excludes any component, step, or procedure not specifically delineated or listed. The term “or,” unless stated otherwise, refers to the listed members individually as well as in any combination. Use of the singular includes use of the plural and vice versa.
As used throughout this specification, the abbreviations given below have the following meanings, unless the context clearly indicates otherwise: “=” means “equal(s)” or “equal to”; “<” means “less than”; “>” means “greater than”; “<” means “less than or equal to”; ≥” means “greater than or equal to”; “@” means “at”; μm=micron(s), g=gram(s); mg=milligram(s); mW/m-K=milliWatt(s) per meter-degree Kelvin; L=liter(s); mL=milliliter(s); g/mL=gram(s) per milliliter; g/L=gram(s) per liter; kg/m3=kilogram(s) per cubic meter; ppm=parts per million by weight; pbw=parts by weight; rpm=revolutions per minute; m=meter(s); mm=millimeter(s); cm=centimeter(s); □m=micrometer(s); min=minute(s); s=second(s); ms=millisecond(s); hr=hour(s); Pa-s=Pascal second(s); mPa-s=milliPascal second(s); g/mol=gram(s) per mole(s); g/eq=gram(s) per equivalent(s); mg KOH/g=milligrams of potassium hydroxide per gram(s); dg/min=decigrams per minute; kg/hr=kilogram(s) per hour; nm=nanometer(s); Mn=number average molecular weight; Mw=weight average molecular weight; pts=part(s) by weight; 1/s or sec-1=reciprocal second(s) [s-1]; ° C.=degree(s) Celsius; mmHg=millimeters of mercury; psig=pounds per square inch; kPa=kilopascal(s); %=percent; vol %=volume percent; mol %=mole percent; and wt %=weight percent.
Unless stated otherwise, all percentages, parts, ratios, and the like amounts, are defined by weight. For example, all percentages stated herein are weight percentages (wt %), unless otherwise indicated.
In its broadest embodiment, the present invention includes a multilayer coextruded film structure for producing a recycle-ready packaging material. The multilayer coextruded film structure includes at least two or more polymeric layers; wherein at least one of the polymeric layers comprises at least one fluorescent tracer substance.
The fluorescent tracer used in the multilayer coextruded film structure has an absorbance wavelength and an emission wavelength when exposed to ultra violet light. Fluorescent tracers absorb ultra-violet light whose spectrum with wavelength goes from 100 nm to 400 nm. For example, a fluorescent tracer can be exposed to ultra-violet UV-A in a wavelength range of from 320 to 400 nm. The fluorescent tracer absorbs this wavelength of 320 to 400 nm; and then, the fluorescent tracer re-emits visible light in the visible blue range of from 400 nm to 480 nm. In the broadest scope of the present invention, the fluorescent tracer is exposed to ultra violet light at an absorbance wavelength of UV light in the range of from 100 nm to 400 nm; and a re-emission wavelength of visible light in the range of from 380 nanometers to 700 nm. In general, the fluorescent tracer, when not exposed to UV light, is invisible to the naked eye in its original state. However, when the fluorescent tracer is exposed to UV light a detectable fluorescence (or luminescence) emits from the fluorescent tracer and then the fluorescent tracer becomes visible to the naked eye. The visually detectable fluorescence of the fluorescent tracer provides visible identification, for example, of a recycle-ready packaging material made from the multi-layer film structure containing the fluorescent tracer. The visible identification, in turn, provides the capability of sorting the recycle-ready packaging material from non-recycle-ready packaging materials.
In one preferred embodiment, at least one of the two or more polymeric layers of the multilayer coextruded film structure comprises at least one barrier layer; and at least one of the two or more polymeric layers of the multilayer coextruded film structure contains the fluorescent tracer, other than the barrier layer. For example, one general embodiment of the present invention includes a multilayer barrier film structure comprising: (I) at least one first layer comprising a polyolefin component; wherein the polyolefin component comprises: (Ia) a first component comprising at least one polyolefin polymer component selected from the group consisting of ethylene homopolymer, ethylene copolymer, polypropylene homopolymer, polypropylene copolymer, and combinations thereof; (Ib) a second component comprising at least one functional polymer component; and (Ic) a third component comprising at least one compatibilizer component, wherein the at least one compatibilizer comprises an anhydride, a carboxylic acid functionalized ethylene/alpha-olefin interpolymer, and combinations thereof; and wherein the compatibilizer has a melt viscosity at 177° C. of less ≤200 mPa-s (200,000 cP) and a density of from 0.855 g/cm3 to 0.94 g/cm3; (II) at least one second tie layer comprising a maleic-anhydride grafted polymer with a melt index of less than 50 dg/min; (III) at least one third barrier layer comprising at least one polar polymer, and (IV) at least one fluorescent tracer present in the at least one first layer, the at least one second layer, or combinations thereof; wherein the at least one fluorescent tracer has an absorbance wavelength (ultraviolet radiation) in the range of from 100 nm to 400 nm wherein the energy is invisible; and an emission wavelength in the range of from 400 nm to 480 nm wherein the energy is visible. Thus, when the film layer does not contain at least one fluorescent tracer and the film layer is exposed to UV light, the radiation of the UV light is invisible to the naked eye in the film's original state; and when the film layer contains a fluorescent tracer, the fluorescent tracer provides detectable fluorescence and becomes visible to the naked eye when the fluorescent tracer is exposed to ultra violet light. Advantageously, the detectable fluorescence provides visible identification of a recycle-ready barrier packaging material made from the multi-layer barrier film structure; and the visible identification provides the capability of sorting the recycle-ready barrier packaging material from non-recycle-ready packaging materials.
In one general embodiment, the first layer of the multilayer barrier film structure is a polyolefin component including: (Ia) a first component including at least one polyolefin polymer component; (Ib) a second component including at least one functional polymer component; (Ic) a third component comprising at least one compatibilizer component; and (Id) optionally, one or more other compounds, as desired.
First Polyolefin Polymer Component
In one embodiment, the first component, component (Ia), includes at least one polyolefin polymer component selected from the group consisting of, for example, ethylene homopolymer (e.g., DMDA-8007 NT 7 available from The Dow Chemical Company), ethylene copolymer (e.g., DOWLEX™ 2045 G available from The Dow Chemical Company), polypropylene homopolymer (e.g., H110-02N available from Braskem), polypropylene copolymer (e.g., DS6D81 available from Braskem), and combinations thereof.
In general, the first component is present in the first polyolefin layer of the multilayer barrier film structure in the range of from 60 wt % to 94 wt %. Any and all ranges between 60 wt % and 94 wt % are included herein and disclosed herein, for example, the first component can be present in the range of from 65 wt % to 90 wt % in one embodiment, from 70 wt % to 87 wt % in another embodiment, or from 75 wt % to 82 wt % in still another embodiment.
Second Functional Polymer Component
In one embodiment, the second component, component (Ib), can include at least one functional polymer component including, for example, but are not limited to, a maleic anhydride functionalized polyolefin (e.g., AMPLIFY™ TY 1353 available from The Dow Chemical Company), acrylate ethylene copolymer (e.g., AMPLIFY™ EA 101 available from The Dow Chemical Company), ethylene vinyl acetate (e.g., ELVAX™ 450 available from The Dow Chemical Company), and mixtures thereof.
Generally, the functional polymer component can be present in the polyolefin layer in the range of from 0.1 wt % to 35 wt %. Any and all ranges between 0.1 wt % and 35 wt % are included herein and disclosed herein, for example, the functional polymer component can be present in the range of from 2 wt % to 16 wt % in one embodiment, from 4 wt % to 12 wt % in another embodiment, or from 6 wt % to 11 wt % in still another embodiment.
Third Compatibilizer Component
In one general embodiment, the at least one compatibilizer, component (Ic) includes for example, an anhydride, a carboxylic acid functionalized ethylene/alpha-olefin interpolymer, and combinations thereof. The term “interpolymer,” as used herein, refers to polymers prepared by the polymerization of at least two different types of monomers. The generic term interpolymer thus includes copolymers (employed to refer to polymers prepared from two different types of monomers), and polymers prepared from more than two different types of monomers.
The term, “ethylene/α-olefin interpolymer,” as used herein, refers to an interpolymer that comprises, in polymerized form, a majority amount of ethylene monomer (based on the weight of the interpolymer), and at least one α-olefin.
The term “anhydride and/or carboxylic acid functionalized ethylene/alpha-olefin interpolymer,” as used herein, refers to an ethylene/alpha-olefin interpolymer that comprises at least one anhydride group and/or at least one acid group (for example, —COOH formed by the hydrolysis of an anhydride) linked by a covalent bond.
The compatibilizer, component (Ic), useful in the present invention can include any one or more compatibilizers described, for example, in U.S. Pat. No. 10,300,686. For example, in one embodiment, an anhydride and/or carboxylic acid functionalized ethylene/alpha-olefin interpolymer useful in the present invention are interpolymers having a melt viscosity in the range of from 2000 cP to 50,000 cP at 350° F. (177° C.); a density of from 0.855 g/cm3 to 0.940 g/cm3; a molecular weight distribution (MWD) (Mw/Mn) from 1.1 to 5.0; a weight average molecular weight (Mw) in the range of from 2000 g/mole to 50,000 g/mole; a melt index (I2), or calculated melt index (I2) (2.16 kg, 190 C), in the range of from 300 g/10 min to 1500 g/10 min; and a percent crystallinity, as determined by DSC, in the range of from 2 percent to 40 percent
In one preferred embodiment, the compatibilizer can include, for example, a functionalized ethylene/α-olefin copolymer such as RETAIN 3000 (available from The Dow Chemical Company).
In a general embodiment, the compatibilizer is present in the polyolefin component layer (component I) in the range of from 1 wt % to 35 wt %. Any and all ranges from 1 wt % to 35 wt % are included herein and disclosed herein, for example, the compatibilizer can be present in the polyolefin layer in the range of from 5 wt % to 30 wt % in one embodiment, from 10 wt % to 25 wt % in another embodiment, and from 15 wt % to 22 wt % in still another embodiment.
The tie layer, component (II) or the second layer of the multilayer barrier film structure, can be any conventional tie layer used to adhere two polymeric layers together as known in the art such as the tie layer described, for example, in U.S. Pat. No. 10,300,686. In one preferred embodiment, the tie layer can include, for example, a polymer with a maleic anhydride (MAH)-grafted functionality, i.e., a maleic-anhydride grafted polymer such as a MAH-grafted ethylene-based polymer as described in U.S. Pat. No. 10,300,686.
For example, in one embodiment, a MAH-grafted ethylene-based polymer useful in the present invention are polymers having a MAH-graft level of from 0.05 wt % to 1.20 wt %, based on the weight of the MAH-grafted polymer; and a melt index (I2) from 0.5 to 10 g/10 min.
The multilayer barrier film structure of the present invention also includes as a third layer, a barrier layer comprising a polar polymer. The term “polar polymer,” as used herein, refers to polymer formed from at least one monomer that comprises at least one heteroatom. Some examples of heteroatoms include O, N, P and S.
In various embodiments, the polar polymer can be selected from an ethylene vinyl alcohol polymer (EVOH) (such as Eval H171B available from Kuraray), a polyamide (PA) (such as Nylon 6, Nylon 66, and Nylon 6/66 available from DuPont), and combinations thereof. In a preferred embodiment, the multilayer barrier film structure includes, for example, EVOH as the polar layer; and in another preferred embodiment, the multilayer barrier film structure includes, for example, at least one polar layer comprising a nylon selected from the group consisting of nylon 6, nylon 66, nylon 6/66, and combinations thereof. In another embodiment, the polar layer comprises at least one layer of at least one of the above-mentioned nylon compounds, and at least one layer of EVOH.
In various embodiments, the polar polymer has a melt index (I2) (2.16 kg, 190° C.) of from 0.1 g/10 min to 40 g/10 min in one embodiment, from 0.2 g/10 min to 20 g/10 min in another embodiment, and from 0.5 g/10 min to 10 g/10 min in still another embodiment. In various embodiments, the polar polymer has a density from 1.00 g/cc to 1.30 g/cc in one embodiment, and from 1.10 g/cc to 1.20 g/cc (1 cc=1 cm3) in another embodiment.
The multilayer barrier film structure of the present invention also includes a fluorescent tracer, component (IV). In one embodiment, the fluorescent tracer component can be added to any layers of the above-described multilayer barrier film structure, other than the barrier layer. In a preferred embodiment the fluorescent tracer is added to a layer made of polyethylene (PE). In another preferred embodiment, the fluorescent tracer is best added to the above-described first polyolefin layer, the second functional polymer layer, or to both the first and second layers to achieve the targeted film performance. Surprisingly, it has been found that adding the fluorescent tracer to the barrier or polar polymer layer, the fluorescence (or luminescence) of the fluorescent tracer can diminish; and possibly, other mechanical properties of the polar polymer layer or the multilayer barrier film overall can also diminish. Thus, in a preferred embodiment, the fluorescent tracer is added to any one or more of the layers of the multilayer barrier film structure other than the barrier layer.
For example, the multilayer film structure can include a monolayer of 100% a barrier layer in combination with other layers to make a multilayer packaging film for packaging applications, and a laminated film layer for a packaging film product.
Examples of the fluorescent tracers, component (IV), useful in the present invention can include, derivatives of the bis-benzoxazole type such as bis-benzoxazolyl-stilbene, bis-benzoxazolyl-thiophene, and mixtures thereof. Examples of commercial fluorescent tracers useful in the present invention can include 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole) such as Tinopal® OB Fluorescent Whitening Agent (available from BASF); Cromex PE-BO 15164-4315164 (available from Cromex); and mixtures thereof.
Generally, the fluorescent tracer used in the film-forming composition is invisible to the naked eye when the fluorescent tracer is in its original state. However, when the fluorescent tracer is exposed to ultra violet (UV) light, the fluorescent tracer emits a luminescent light which is visible to the naked eye.
In general, fluorescent tracers function by absorbing light in the UV-A, UV-B and UV-C range and re-emitting light in the visible blue range. For example, the correlating wavelength in the UV range is from 100 nm to 400 nm; and the correlating wavelength in the visible blue range is from 380 nm to 700 nm. Thus, to be visible and promote the fluorescent effect of the fluorescent tracer, the fluorescent tracer can be exposed to UV light at a UV light wavelength in the range of from 100 nm to 400 nm in one general embodiment, from 100 to 300 in another embodiment, and from 100 to 200 in still another embodiment; and the visible light wavelength is in the range of from 380 nm to 700 nm in one general embodiment, from 400 nm to 500 nm in another embodiment, and from 400 nm to 480 nm in still another embodiment.
Ultraviolet radiation is invisible energy in the wavelength range of from 100 to 400 nanometers (nm). Fluorescent tracers can be used at low loading levels; and in a preferred embodiment, at least one layer of the multilayer film contains the fluorescent tracer embedded in a sufficient quantity in the layer to provide a luminescence at a wavelength of from 380 nanometers to 700 nanometers to allow a sorter to visually identify the multilayer film with a naked eye when the film is exposed to a UV light source. For example, the fluorescent tracers can be present in the first and/or the second layer of the multilayer barrier film structure of the present invention in a concentrations range of from 50 ppm to 100,000 ppm based on the overall composition. More than 100,000 ppm of fluorescent tracer can be added to the overall composition if desired; however, after adding 100,000 ppm of fluorescent tracer to the composition, there is little economic benefit in adding more fluorescent tracer. Any and all ranges between 50 ppm and 100,000 ppm are included herein and disclosed herein, for example, the fluorescent tracer component can be present in the first and/or the second layer of the multilayer barrier film structure in the range of from 50 ppm to 40,000 ppm in one embodiment, and from 50 ppm to 30,000 ppm in another embodiment, from 50 ppm to 20,000 ppm in still another embodiment, and from 50 ppm to 10,000 ppm in yet another embodiment.
As aforementioned, in one preferred broad embodiment, and not to be limited thereby, the amount of fluorescent tracer used in at least one layer of the multilayer film can be in the range of from 50 ppm to 100,000 ppm. The amount of fluorescent tracer used in one or more layers of the multilayer film, however, can depend on whether one or more layers used in the multilayer film are colored or whether one or more (or all layers) used in the multilayer film are transparent. For example, when at least one layer (or, e.g., all of the layers) used in the multilayer film is transparent, the amount of the fluorescent tracer used in at least one of the transparent layers can be from 50 ppm to 10,000 ppm; and when at least one layer used in the multilayer film is colored, such as a white layer, the amount of fluorescent tracer used in one or more layers of the multilayer film can be in the range of from 50 ppm to 20,000 ppm.
In other various embodiments, one or more optional compounds or additives, component (V), can be added to one or more component layers of the multilayer barrier film structure including, for example, optionally one or more fillers such as mineral fillers; optionally one or more pigments, e.g. titanium dioxide, mica, calcium carbonate, silica, zinc oxide, milled glass, aluminum trihydrate, talc, antimony trioxide, fly ash, and clay; pigments including masterbatches for imparting color to the polymer component of the film structure; sealants; and mixtures thereof.
In some embodiments, the concentration of the optional compounds, component (V), when used in any one or more layers of the multilayer barrier film structure and/or the film-forming composition disclosed herein, includes, for example, from 0 wt % to 10 wt % in one embodiment, from 0.1 wt % to 8 wt % in another embodiment, and from 0.1 wt % to 5 wt % in still another embodiment.
Embodiments directed to the use of masterbatches to provide a color additive, such as a white masterbatch or a black masterbatch described in this disclosure, the concentration of the optional color additive can be from 0 wt % to 20 wt % in one embodiment, from 0.1 wt % to 18 wt % in another embodiment, from 0.1 wt % to 15 wt % in still another embodiment, from 0.1 wt % to 10 wt % in yet another embodiment, from 0.1 wt % to 5 wt % in even yet another embodiment, and from 0.1 wt % to 3 wt % in even still another embodiment.
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With reference to
The multilayer film structures 40 and 50 shown in
In general, the process for producing the multilayer film of the present invention includes, for example, the step of:
(i) providing a film-forming composition comprising blending or mixing: (α) at least one polymer resin; (β) at least one fluorescent tracer; (γ) at least one compatibilizer compound; and (Δ) any optional components, if desired. The fluorescent tracer is invisible to the naked eye in its original state and wherein the fluorescent tracer is visible to the naked eye when the fluorescent tracer is exposed to ultra violet light; and
(ii) processing the film-forming composition into a film using a blown film extrusion line process to form a film member; wherein the film member comprises a polyolefin film containing the fluorescent tracer embedded in and homogeneously/uniformly dispersed or distributed throughout the matrix of the polyolefin film produced during the processing step (ii). This processing step (ii) can be carried out in combination with other layers to produce the multilayer film.
In one embodiment of the process, the components (α)-(γ) and optionally (Δ) are mixed in step (i), in each of the components' molten state at a temperature of from 180° C. to 250° C. in one embodiment, from 185° C. to 235° C. in another embodiment, from 185° C. to 230° C., and from 190° C. to 230° C. in still another embodiment. Conventional mixing equipment used by those skilled in the field of mixing is used in the mixing step (i). Once components (α), (β), (γ) and optionally (Δ) are thoroughly mixed together, the resulting molten mixture is allowed to cool to room temperature to form a solid material such as a plurality of resin polymer pellets containing the fluorescent tracer embedded in the pellets. After the resin polymer pellets are formed, the pellets can be processed into a film member using conventional equipment known to those skilled in the field of manufacturing film. For example, in one preferred embodiment, the film is produced, for example, using a conventional blown film extrusion process and equipment.
The resulting multilayer barrier film produced by the above film producing process, after undergoing the production process, has the beneficial properties of being recycle-ready, being fluorescent, being visually identifiable for recycling purposes, and being sortable for recycling purposes. The resulting multilayer barrier film produced, after undergoing the production process to introduce the fluorescent tracer into at least one of the layers of the multilayer barrier film is subjected to, and exposed to, a UV light to identify the multilayer barrier film as being recyclable and sortable from a stream of different materials.
The multilayer barrier film produced as described above can be used in a variety of applications including, for example but not limited to, film applications such as flexible films, semi-flexible films, rigid films, and semi-rigid films. The multilayer barrier films or recycle-ready films disclosed herein may be converted into films, sheet, or rigid structures. And, from the multilayer barrier films, articles can be manufactured including articles such as a stand-up-pouch, pouch, flexible food packaging, frozen food packaging, food trays and lids, and the like. In one preferred embodiment, the article produced is used in packaging applications wherein the film is used to manufacture a flexible packaging product for packaging various items, for example, food items.
A flexible packaging article produced from the multilayer barrier film structure of the present invention can be produced by any method known to those skilled in the art such as by using a blown film extrusion process and a cast film extrusion process.
Then, once the original flexible packaging article is used and discarded into a recycle waste stream, the original flexible packaging article can be passed through a recycling process which includes a sorting step and recycling process step.
During the sorting step, the original flexible packaging article made from the multilayer barrier film containing the fluorescent tracer, is subjected to, and exposed to, a UV light as the waste stream containing the original flexible packaging article passes by a sorter wherein the fluorescent tracer in the original flexible packaging article emits a luminescent light providing ease of identification by visually detecting, with the naked eye, the original flexible packaging article; and providing ease of identification that the original flexible packaging article is recyclable. As the sorter identifies the original flexible packaging article as being recyclable, the original flexible packaging article is removed from the waste stream and placed in a recycle stream which is further processed into recyclable material.
Beneficially, the multilayer barrier film containing the fluorescent tracer and the luminescence of the fluorescent tracer with UV light allows an operator to easily identify and sort the original flexible packaging in the waste stream, not depending on any coating or printing stamp. And, through the use of a fluorescent tracer, the process' ease of identification of the final film during the recycling material sorting can be carried out without impacting the final film's appearance.
In a preferred embodiment, the original flexible packaging article, after the original flexible packaging article is identified, sorted and recycled, is converted to a recyclable material which can be further processed to manufacture a post-consumer article. For example, the recyclable material can be used in the same flexible packaging application to make another recycled flexible packaging article; or the recyclable material can be used in another different application. The present invention can also be used either for printed and non-printed packaging.
In general, the process of making a flexible packaging article from the recycled material includes the following process steps:
(A) providing a mixed recycle stream containing a mixture of different articles made of different materials; the mixed stream including the original flexible packaging article with the fluorescent tracer embedded therein;
(B) exposing the stream of step (A) including the original flexible packaging article to ultra violet light such that the original flexible packaging article emits a luminescent light providing ease of identification by visually detecting with the naked eye the original flexible packaging article; and providing ease of identification that the original flexible packaging article is recyclable;
(C) sorting the luminescent original flexible packaging article from the mixed stream;
(D) processing the original flexible packaging article sorted in step (C) to form a recyclable material such as pelletizing the material to form pellets which can be further processed, for example, in a blown film extrusion line; and
(E) processing the recyclable material, such as the pellets from step (D), to form a recycled flexible packaging article.
The following Inventive Examples (Inv. Ex.) and Comparative Examples (Comp. Ex.) (collectively, “the Examples”) are presented herein to further illustrate the present invention in detail but are not to be construed as limiting the scope of the claims. Unless otherwise stated all parts and percentages are by weight.
Various terms and designations used in the Examples are explained as follows:
“UV light” stands for ultra violet light.
“B.U.R.” stands for blow up ratio.
Various raw materials or ingredients used in the Examples are explained in Table I as follows:
The film-forming polymer resin formulations or compositions, which are used in the Examples to produce at least one of the layers of the multilayer barrier film product, includes: (a) a polyolefin polymer resin compound; (b) a fluorescent maker substance of the present invention; and (c) a compatibilizer compound. The film-forming polymer resin compositions used in the Examples are prepared is as follows: The fluorescent tracer can be added to any layer of the proposed film structure, except for the barrier layer being composed by PA or EVOH. Regardless of the number of layers used for the multilayer film structure, the fluorescent tracer can be added to any layer. Various methods known in the art of adding the fluorescent tracer and mixing the fluorescent tracer with the above components to make the film-forming composition can be used.
The multilayer films and film structures of the present invention can be made using a blown film layer extrusion process or a cast film layer extrusion process and other methods known in the art of film manufacturing.
A standard multilayer barrier film (e.g., a 5-layer barrier film) was produced via a conventional blown film extrusion process with standard materials and formulations commonly utilized by the film-making industry for forming the layers of the barrier film. The 5-layer structure (having layers A-E) of the barrier film of Comp. Ex. A is described in Table II and shown in
Comp. Ex. A barrier film was produced on a blown film line (available from COLLIN Lab & Pilot Solutions GmbH) having a B.U.R. of 3.0; a die diameter of 80 mm; and a die gap of 1.8 mm. The barrier film was produced using the following processing conditions:
Temperature profile: 190° C./210° C./220° C./235° C./235° C./235° C./235° C.;
Melt temperature: 219° C.;
Die temperature: 235° C.;
RPM: 59 rpm (revolutions per minute);
Output: 22.42 kg/hr; and
Pressure: 258 bar.
To evaluate the effect of the addition of a fluorescent tracer to a film which is exposed to UV light, two coextruded multilayer barrier films (e.g., a 5-layer barrier films) of the present invention (Inv. Ex. 1 and Inv. Ex. 2) were produced using the same blown film extrusion process described above for producing the barrier film of Comp. Ex. A. A first inventive barrier film (Inv. Ex. 1) was produced containing 4 wt % of an optical brightener (PE-BO 15164-4315164 produced by Cromex); and a second inventive barrier film (Inv. Ex. 2) was produced containing 8 wt % of the above optical brightener produced by Cromex. The optical brighter compound was added to the adhesive layers (layers A and E) of the coextruded barrier films (Inv. Ex. 1 and Inv. Ex. 2). The 5-layer structure (layers A-E) of the of the first and second films are described in Table IV and shown in
The barrier films of Comp. Ex. A, Inv. Ex. 1 and Inv. Ex. 2 were exposed to UV light in a black room, and a visual analysis of the films was conducted. The films of Inv. Ex. 1 and Inv. Ex. 2 were produced with 0.96 wt % and 1.92 wt % of fluorescent tracer, respectively, added into the overall film composition; and the films with the fluorescent tracer were visually identified under the black light. In
Two white multilayer films, one white film with a fluorescent tracer (Inv. Ex. 3) and another separate white film without a fluorescent tracer (Comp. Ex. B), were produced at a thickness of 80μ, on a blown film line (Collin) having a B.U.R. of 3.0, a die diameter of 80 mm, and a die gap of 1.8 mm. The white films were produced using the following processing conditions:
Temperature profile: 190° C./210° C./220° C./235° C./235° C./235° C./235° C.
Melt temperature: 219° C.;
Die temperature: 235° C.;
RPM: 59 rpm;
Output: 22.42 kg/hr; and
Pressure: 258 bar.
The standard multilayer (e.g., a 3-layer film) white film (Comp. Ex. B) was produced via a conventional blown film extrusion with a standard materials and formulations usually utilized by the film-making industry for forming the layers of a barrier film. The film produced having the 3-layer structure (A-C) described in Table V and shown in
The coextruded multilayer film (e.g., a 3-layer film) of the present invention (Inv. Ex. 3) was produced using the same blown film extrusion process described above for producing the film of Comp. Ex. B. The inventive film (Inv. Ex. 3) was produced containing 1.6 wt % of a fluorescent tracer (PE-BO 15164-4315164 supplied by Cromex). The fluorescent tracer was added to layer C of the coextruded white barrier film of Inv. Ex. 3. The 3-layer structure (having layers A-C) and the materials and formulations utilized for forming the layers of the white film are described in Table V and shown in
The material, DOWLEX™ TG 2085B, is a LLDPE with 0.919 g/cc of density and 0.95 g/10 min of melt index (at 190° C. and 2.16 kg). The white pigment masterbatch used in forming the two white films was material, BR 1000/5728IEK, produced by Ampacet.
The white films of Comp. Ex. B and Inv. Ex. 3 were exposed to UV light in a black room, and a visual analysis of the films was conducted. The film of Inv. Ex. 3 was produced with 1.6 wt % of fluorescent tracer added into the overall film composition; and the film with the fluorescent tracer was visually identified under the black light. In
In
In these Examples, two black multilayer films, one black film with a (Inv. Ex. 4) and another separate black film without a fluorescent tracer (Comp. Ex. C), were produced at a thickness of 80μ, on a blown film line (Collin) having a B.U.R. of 3.0, a die diameter of 80 mm, and a die gap of 1.8 mm. The black films were produced using the same process and conditions as used in Inv. Ex. 3 and Comp. Ex. B.
The standard multilayer (e.g., a 3-layer film) black film (Comp. Ex. C) was produced via a conventional blown film extrusion with standard materials and formulations usually utilized by the film-making industry for forming the layers of a film. The film produced having the 3-layer structure (A-C) and the materials and formulations as described in Table VI and shown in
The coextruded multilayer (e.g., a 3-layer film) black film (Inv. Ex. 4) of the present invention was produced using the same blown film extrusion process described above for producing the black film of Comp. Ex. C. The inventive black film (Inv. Ex. 4) was produced containing 1.6 wt % of a fluorescent tracer (PE-BO 15164-4315164 supplied by Cromex). The optical brighter compound was added to the layer C of the coextruded black film of Inv. Ex. 4. The 3-layer structures (layers A-C) and the materials and formulations utilized for forming the layers of the film as described in Table VI and shown in
The black films of Comp. Ex. C and Inv. Ex. 4 were exposed to UV light in a black room, and a visual analysis of the films was conducted. The film 70 of Inv. Ex. 4 was produced with 1.6 wt % of fluorescent tracer added into the overall film composition; and the film with the fluorescent tracer was visually identified under the black light. In
In
In one embodiment, the film-forming composition useful in the present invention includes (α) at least one polyolefin polymer resin; (β) at least one fluorescent tracer; and (γ) at least one compatibilizer compound. In another embodiment, the film-forming composition includes a fluorescent tracer such as bis-benzoxazolyl-stilbene, bis-benzoxazolyl-thiophene, and mixtures thereof. In addition, inorganic fluorescent tracers can be used in the present invention. For example, the inorganic fluorescent tracers can include oxide crystals doped with ytterbium Yb3+sensitizer ions and either erbium (Er3+), holmium (Ho3+) or thulium (Tm3+) activator ions; or mixtures thereof.
In another embodiment, the fluorescent tracer is added to the film-forming composition at a concentration of from 50 ppm to 100,000 ppm.
In another embodiment, the polyolefin polymer resin component of the film-forming composition is polyethylene, polypropylene, polyamide, ethylene vinyl alcohol or mixtures thereof.
In another embodiment, the fluorescent tracer of the composition is a derivative of bis-benzoxazole.
In another embodiment, the compatibilizer compound of the composition is an anhydride, a carboxylic acid functionalized ethylene/alpha-olefin interpolymer, and combinations thereof.
In another embodiment, the concentration of the polymer resin is from 60 wt % to 94 wt %; the concentration of the fluorescent tracer is from 50 ppm to 100,000 ppm; and the concentration of the compatibilizer compound is from 1 wt % to 35 wt %.
In still another embodiment of the present invention includes a process for producing a film-forming composition useful for making at least one layer of a multilayer recycle-ready barrier packaging material, the process comprising admixing: (α) at least one polyolefin polymer resin; (β) at least one fluorescent tracer; and (γ) at least one compatibilizer compound; wherein the fluorescent tracer is invisible to the naked eye in its original state; and wherein the fluorescent tracer provides detectable fluorescence and becomes visible to the naked eye when the fluorescent tracer is exposed to ultra violet light to provide identification of the recycle-ready barrier packaging material and the capability of sorting the recycle-ready barrier packaging material from non-recycle-ready packaging materials.
In yet another embodiment of the present invention includes a multilayer barrier film structure useful for making a multilayer recycle-ready barrier packaging material, the film structure comprising:
(i) at least one polyolefin component layer comprising: (ia) at least one polyolefin polymer resin; (ib) at least one fluorescent tracer; and (ic) at least one compatibilizer compound; wherein the fluorescent tracer is invisible to the naked eye in its original state; and wherein the fluorescent tracer provides detectable fluorescence and becomes visible to the naked eye when the fluorescent tracer is exposed to ultra violet light to provide identification of the recycle-ready barrier packaging material and the capability of sorting the recycle-ready barrier packaging material from non-recycle-ready packaging materials
(ii) at least one tie layer; and
(iii) at least one polar polymer layer; wherein the tie layer and the polar layer do not contain the compatibilizer compound.
In another embodiment, the multilayer barrier film structure includes a fluorescent tracer embedded in and homogeneously distributed throughout the matrix of the polyolefin component layer; and the fluorescent tracer is visible to the naked eye when the fluorescent tracer is exposed to ultra violet light at a wavelength of from 100 nm to 400 nm; and a visible light wavelength of from 380 nm to 700 nm.
In still another embodiment, the present invention includes a process for producing a multilayer barrier film structure useful for making a multilayer recycle-ready barrier packaging material, the process comprising the steps of:
(1) providing:
(2) processing the layer compositions (i), (ii) and (iii) into a multilayer barrier film structure using a blown film extrusion line process to form the multilayer barrier film structure; wherein the multilayer barrier film structure comprises a polyolefin component layer containing the fluorescent tracer embedded in and homogeneously distributed throughout the matrix of the polyolefin component layer.
In even yet another embodiment of the present invention, the fluorescent tracer embedded in and homogeneously distributed throughout the matrix of the polyolefin component layer is visible to the naked eye when the fluorescent tracer is exposed to ultra violet light at a wavelength of from 100 nm to 400 nm; and a visible light wavelength of from 380 nm to 700 nm.
In another embodiment, the multilayer recycle-ready barrier packaging article includes a flexible stand-up pouch.
In even still another embodiment, the present invention includes a process of making a recycled article comprising the steps of:
(A) providing a stream containing a mixture of different articles that includes the multilayer recycle-ready barrier packaging article of claim 14;
(B) exposing the stream of step (A) to ultra violet light to promote the fluorescent effect of the fluorescent tracer such that the fluorescence of the multilayer recycle-ready barrier packaging article is detected visually by the naked eye and identified as being recyclable;
(C) sorting the multilayer recycle-ready barrier packaging article from the stream of step (B);
(D) processing the multilayer recycle-ready barrier packaging article sorted from step (C) to form a stream of recyclable material; and
(E) processing the recyclable material stream from step (D) to form a recycled material.
Another embodiment of the present invention includes a recycled material made using the above process.
In still another embodiment, the recycled material includes a flake, a powder or a pellet.
In yet another embodiment, the present invention multi-layer barrier film structure comprises a blend of from 5 weight percent to 30 weight percent of a sealant polymer; and from 70 weight percent to 95 weight percent of the ethylene homopolymer or ethylene alpha-olefin copolymer.
In another embodiment, the multi-layer film structure of the present invention may include at least one transparent layer wherein the multilayer film is transparent; or the multi-layer film structure may, optionally, include a color material in at least one of the polymeric layers of the multi-layer film structure to provide a color to the multilayer film structure.
The white films and black films produced in the Examples and shown in
In one preferred broad embodiment, and not to be limited thereby, the amount of fluorescent tracer used in at least one layer of the multilayer film can be in the range of from 50 ppm to 100,000 ppm. The amount of fluorescent tracer used in one or more layers of the multilayer film can depend on whether one or more layers used in the multilayer film are colored or whether one or more (or all layers) used in the multilayer film are transparent. For example, when at least one layer (or, e.g., all of the layers) used in the multilayer film is transparent, the amount of the fluorescent tracer used in at least one of the transparent layers can be from 50 ppm to 10,000 ppm; and when at least one layer used in the multilayer film is colored, such as a white layer, the amount of fluorescent tracer used in one or more layers of the multilayer film can be in the range of from 50 ppm to 20,000 ppm.
| Number | Date | Country | |
|---|---|---|---|
| 63127841 | Dec 2020 | US |
