Patent Application
20100267299
The invention relates to vinyl chloride polymer (PVC) having an elevated moisture vapor transmission rate and/or electrostatic dissipative properties. The incorporation of a hydrophilic polyurethane and/or hydrophilic vinyl polymer(s) into the vinyl chloride polymer imparts moisture vapor permeability and/or electrostatic dissipative properties to the vinyl chloride polymer. Similar modifications can be made to acrylate and urethane polymers to change their moisture vapor permeability and/or static dissipative properties.
U.S. Pat. No. 4,983,662 relates to an aqueous selfcrosslinkable coating composition comprising an aqueous dispersion of at least one polyurethane and having hydrazine (or hydrazone) functional groups and carbonyl functional groups disposed therein to provide a selfcrosslinkable reaction, in which the polyurethane polymer takes part via azomethine formation during and/or after film formation.
U.S. Pat. No. 4,190,566 relates to non-ionic, water-dispersible polyurethanes having a substantially linear molecular structure and lateral polyalkylene oxide chains having about 3 to 30% by weight of lateral polyalkylene oxide polyether chains. The chains consist of about 40-95% ethylene oxide units and 5-60% certain other alkylene oxide units selected from the group consisting of propylene oxide, butylene oxide and styrene oxide.
U.S. Pat. No. 4,092,286 relates to water-dispersible polyurethane elastomers having a substantially linear molecular structure, characterized by (a) lateral polyalkylene oxide units of from about 0.5 to 10% by weight, based on the polyurethane as a whole and (b) a content of ═N+═, —COO− or —SO3− groups of from about 0.1 to 15 milliequivalents per 100 g.
U.S. Pat. No. 5,153,259 discusses aqueous dispersions of polyurethanes. In column 9, line 54, through column 10, line 47, the authors discuss polymerizing various vinyl monomers in the presence of the aqueous dispersions of polyurethanes. In Example 15, column 15, the authors polymerize butyl acrylate and vinylidene chloride in the presence of a polyurethane dispersion.
U.S. Pat. No. 6,794,475 relates to blends of 1) polymers, in latex or dispersion form of a) a least one reactive macromer of at least one alkylene oxide having at least one functional group capable of free-radical transformation, b) optionally other ethylenically unsaturated monomers having at least one carboxylic acid group, c) optionally other co-monomers, and 2) one or more other polymers.
U.S. Pat. No. 6,897,281 discloses breathable polyurethanes having an upright moisture vapor transmission rate (MVTR) of more than about 500 g/m2/24 hrs.
U.S. Pat. No. 5,130,402 describes coating compositions comprising blocked urethane prepolymers and curatives and PVC plastisols containing the blocked urethane prepolymers and curatives.
U.S. Pat. No. 5,314,942 discloses polymer dispersions containing a vinyl polymer and a nonionic water-dispersible polyurethane having pendant polyoxyethylene chains.
U.S. Pat. No. 6,498,210 discloses thermoplastic compositions for making a liquid impermeable and moisture vapor permeable layer comprising a thermoplastic layer and suitable hydrophilic plasticizers.
U.S. Pat. No. 7,358,295 describes an anti-static polymer composition comprising a thermoformable, moldable, hybrid urethane-vinyl polymer compositions.
WO 2004/014445 discloses polymeric compositions for making a liquid impermeable, moisture vapour permeable, layer from thermoplastic polymers and suitable hydrophilic plasticizers which are covalently bonded to said thermoplastic polymers.
Vinyl chloride polymer (PVC) compositions with improved moisture vapor transmission rates and static dissipative properties are described. The moisture vapor permeability and static dissipative properties are imparted from the incorporation of high moisture vapor transmission hydrophilic polymer compositions. These PVC compositions are often plasticized to result in flexible PVC compositions with improved moisture vapor transmission. The hydrophilic polymer(s) are characterized by their poly(ethylene oxide) or another polar component which imparts the moisture vapor transmission. The hydrophilic polymer can be incorporated into the PVC during the polymerizations of the PVC, after polymerization of the PVC but before drying, during formulation of the PVC, or as a post-add to the final PVC formulation. The hydrophilic polymer can vary widely in molecular weight. Similarly, the hydrophilic polymer(s) can be incorporated into acrylate polymers and/or urethane polymers to promote similar types of moisture vapor and/or static dissipative properties.
Various blends of vinyl chloride polymer (PVC) and a hydrophilic polymer are described to enhance the moisture vapor permeability and static dissipative properties of the vinyl chloride polymer composition, typically in film form. Vinyl chloride polymers, optionally plasticized, are used in many applications to provide inexpensive articles with good resistance to liquid water, UV (outdoor exposure), and fire. Examples include vinyl house siding, vinyl wall coverings, wallpaper, vinyl flooring, supported and unsupported dipped vinyl goods such as gloves, and waterproof coatings on canvas and other industrial goods. A problem for many vinyl chloride goods is that they are so impermeable to water that moisture can become trapped on one side of the vinyl chloride article. This leads to high humidity on that side of the article, discomfort to the wearer (gloves or clothing applications), and potentially mildew and mold growth in construction applications. If vinyl chloride polymer could be made to maintain liquid water barrier properties and have increased (adjustable) moisture vapor permeability, it could be used in more demanding applications such as layers in clothing, roofing, and in damp environments where it would be desirable for moisture vapor to transfer through the film.
Similarly, PVC and some related polymers (acrylates and polyurethanes) are used in films and other shapes in many applications where static dissipative properties are necessary to minimize or prevent static discharges and/or accumulation of charge in the PVC, acrylate, and/or urethane articles or in dissimilar articles brought near or in contact with the PVC, acrylate, or urethane articles. The hydrophilic polymers of this disclosure are also useful in articles made from acrylates, PVC, and urethanes that need static dissipative properties. Such uses are in clean rooms, electronics assembly areas, doorways, flooring, packing materials, etc. The articles may be softwall plastic curtains (such as for clean rooms, warehouses, etc., where one wants to block air and dust travel but may permit entry of totes, skids, or other raw material/finished material containers). The articles may be mats or flooring such as those in cleanrooms or static dissipative assembly areas. The articles may be packaging, display components, electronic housing, thermoformed packaging, cleaning swab heads, foamed packaging (such as foamed packing peanuts), urethane foam, carpet backing, urethane sheets or molded articles, etc.
The increased moisture vapor transmission rates of the present invention are conveniently referred to as the vinyl chloride polymer's moisture vapor transmission rate because the blends contain repeating units from vinyl chloride monomer, and the applications of the polymer compositions are those typically dominated by vinyl chloride polymer, which is optionally plasticized.
Definitions. Unless otherwise indicated, the following terms have the following meanings:
As used herein, the term “wt. %” means the number of parts by weight of monomer per 100 parts by weight of polymer on a dry weight basis, or the number of parts by weight of ingredient per 100 parts by weight of specified composition.
As used herein, the term “molecular weight” means number average molecular weight.
“Bulk polymerization” means the formation of polymer from substantially undiluted monomers. Incidental amounts of solvents, coalescents, plasticizers and/or water may also be present. Further description is given in “Bulk Polymerization”, Vol. 2, pp. 500-514, Encyclopedia of Polymer Science and Engineering, ©1989, John Wiley & Sons, New York, the disclosure of which is incorporated herein by reference.
“Solution polymerization” means a polymerization technique in which both the monomers and resultant polymer are substantially soluble in a diluent (e.g., organic solvents, coalescents, plasticizers and/or water) that is also present. It is described in “Solution Polymerization”, Vol. 15, pp. 402-418, Encyclopedia of Polymer Science and Engineering, ©1989, John Wiley & Sons, New York, the disclosure of which is incorporated herein by reference.
“Dispersion polymerization” means a polymerization technique in which polymerization of the monomers is at least initially carried out by hulk or solution polymerization, with the reaction system thereafter being emulsified or dispersed in an aqueous medium. It includes polymerization reactions in which polymerization is carried out to substantial or total completion before the bulk or solution polymerization system is dispersed in the aqueous medium. It is also known as secondary dispersion.
“Emulsion polymerization” means a polymerization technique in which the monomers are emulsified in an aqueous medium containing a water-soluble initiator. Polymerization occurs predominantly in micelles formed by surfactant and not in the initially formed monomer droplets. The latter serve merely as a reservoir of monomers which diffuse out to find micelles and swell them. This mechanism produces polymer particles which are significantly smaller than original monomer droplets.
“Polymer” means a chemical substance consisting of one or more repeating units characterized by the sequence of one or more types of monomer units and comprising a simple weight majority of molecules containing at least 3 monomer units which are covalently bound to at least one other monomer unit or other reactant. Such molecules can be distributed over a range of molecular weights and can be characterized by number-average and/or weight-average molecular weights and polydispersity index.
“(Meth)acrylate” means either acrylate, methacrylate or both, while “(meth)acrylic” means either acrylic, methacrylic or both.
“Reaction mass in which the polymer is formed” and “reaction mass used to form the polymer by bulk polymerization or solution polymerization” refers to the hulk or solution polymerization reaction system in which the polymers of this invention are formed, whether before polymerization has begun, during polymerization or after polymerization has been completed. It is composed of the monomers being polymerized, other ingredients involved in the polymerization reaction such as initiators, catalysts, chain transfer agents and the like, as well as diluents normally included in solution polymerization systems such as solvents, coalescents and plasticizers.
“Suspension polymerization” means a polymerization technique in which the monomers, normally together with an organic-soluble initiator, are first emulsified in an aqueous medium and thereafter the monomers are caused to polymerize. Because an organic-soluble initiator is used, polymerization occurs throughout the bodies of the emulsified monomer droplets rather than in micelles, as in the case of emulsion polymerization. The result is that the polymer particles formed are typically larger than the polymer particles formed by emulsion polymerization.
Vinyl Chloride Polymer. Vinyl chloride polymers can be prepared by any processes known in the art. Desirably, the vinyl chloride polymer comprises at least 50, in one embodiment at least 75 and in another embodiment at least 85 weight percent repeating units from vinyl chloride monomer. The residual 0-15, or 0-25 or 0-50 weight percent of repeating units can be selected from a variety of free radically polymerizable ethylenically unsaturated monomers. It is intended that the definition of vinyl chloride polymer(s) includes copolymers. The co-polymerizable ethylenically unsaturated monomers can include acrylic and substituted acrylic monomers, for example, acrylic and methacrylic acid; acrylonitrile; alkyl acrylates or alkyl(alk)acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, various methacrylates; olefins such as ethylene; acrylamide; methacrylamide; N-methylolacrylamide; vinyl esters; vinyl ethers; vinyl ketones; vinylidene chloride and heterocyclic vinyl compounds.
The vinyl chloride polymer may be made by any of the free radical polymerization process, e.g., dispersion, emulsion, suspension, etc. The vinyl chloride polymer may be prepared in the presence of other chemicals or polymers, e.g., surface active agents, initiators, polymers, etc. The vinyl chloride polymer may be treated post-polymerization by grafting with other chemicals, irradiation, or otherwise modified. The preparation and use of vinyl chloride polymer is set forth in a review article titled “Vinyl Chloride Polymers, Polymerization” by M. J. Bunten in the Encyclopedia of Polymer Science and Engineering, 2nd Edition, Vol. 17, p. 295-376, ©1989 John Wiley & Sons.
Definition of Acrylate and Urethane Polymer. In this application, the acrylate (base polymer) will be defined to comprise a homopolymer of one or more acrylate monomers or a copolymer of an acrylate monomer or acrylonitrile monomer with one or more other monomers such as styrene, dienes vinyl acetate, vinyl versatates, vinyl amides. In one embodiment, the acrylate polymers will be thermolplastic polymer but in another embodiment, it could be thermoset or rubbery polymers. The polyurethane (base polymer) may be an aliphatic polyurethane (meaning the isocyanate portion is primarily aliphatic) or it might be aromatic or a blend of aliphatic or aromatic. The polyurethane may be thermoplastic or thermoset. The polyol portion of the urethane polymer may be a polyester, polycarbonate, a polyether, etc. The preferred ratio of the hydrophilic polymer agent or additive to the base polymer is about 1 to 25 parts of hydrophilic additive (the part that imparts electrostatic dissipative properties) based on 100 parts of the hydrophilic additive and base polymer blend. The hydrophilic polymer of the present invention can be blended with a matrix or base polymer by almost any technique, e.g., a) the hydrophilic polymer can be put in a plasticizer as was done in some of the PVC examples, b) it could be added neat, c) it could be added in a masterbatch, or d) it could be added in a solvent or carrier that is later evaporated off. The base polymer can be shaped by a variety of methods and may be a foamed material.
Definition of Hydrophilic Polymer. In one embodiment, the hydrophilic polymer is characterized as a hydrophilic polyurethane. In another embodiment, the hydrophilic polymer is a hydrophilic vinyl polymer, e.g., an acrylic or acrylate polymer, a styrene copolymer, a styrene-maleic anhydride copolymer, etc. A common characteristic of hydrophilic polymers in this application is the presence of hydrophilic segments of repeating units from polymerizing hydrophilic monomers, such as ethylene oxide somewhere in the hydrophilic polymer. The remainder of the hydrophilic polymer (i.e., the non-ethylene oxide portion) may be somewhat hydrophobic, even though the name applied is hydrophilic polymer.
Hydrophilic polymers in this application comprise hydrophilic polymers with water attracting poly(ethylene oxide) segments (PEO which is also called PEG (meaning poly ethylene glycol)). While the poly(ethylene oxide) is a necessary component, and we provide ranges on the amount of PEO, poly(propylene oxide) segments may also be present. Poly(ethylene oxide) copolymers with poly(propylene oxide) are commercially available and are a desirable way to incorporate the poly(ethylene oxide) into the hydrophilic polymer(s). While not wishing to be hound by a theory of phase separation between hydrophilic segments such as poly(ethylene oxide) segments and the rest of the vinyl chloride polymer composition, the poly(ethylene oxide) segments, when of sufficient molecular weight, are believed to phase separate from the rest of the components in the vinyl chloride polymer composition and form poly(ethylene oxide) rich domains, which are hydrophilic and can transport moisture through a polymer film containing the poly(ethylene oxide) segments if they (hydrophilic segments) form hydrophilic polymer rich interconnected channels.
At least three different types of attachments of poly(ethylene oxide) segments to a hydrophilic polymer are possible. These poly(ethylene oxide) segments can be in (a) poly(alkylene oxide) side-chain units (implying that the chains extend outward from the hydrophobic polymer backbone). Poly(ethylene oxide) can be b) bound within the hydrophilic polymer chain such that at least two ends of the poly(ethylene oxide) are chemically bonded to the other repeating units of the polymer (this is called in chain). The poly(ethylene oxide) can be c) the last repeating unit of a hydrophilic polymer (this is called a terminal poly(ethylene oxide). Terminal poly(ethylene oxide) on the hydrophilic polymer may have one non-reactive end (e.g., alkoxy capped so it lacks a reactive hydroxyl or amine group) or may have a non-reacted hydroxyl or amine group. Reactive is used in the previous paragraph to mean reactive with isocyanate groups.
Desirably, the ethylene oxide repeat units are present at concentrations of at least 5, 10, 25, 35 or 50 parts by weight per 100 parts by weight of the hydrophilic polymer. Desirably, the poly(ethylene oxide) units of the hydrophilic polymer are present in an amount of at least 2, 3, 5, 10, 15, 25, or 30 parts by weight per 100 parts by weight of vinyl chloride polymer in the final blend of vinyl chloride polymer(s) with hydrophilic polymer (or equivalent amounts in blends of hydrophilic polymer with urethane or acrylate polymers). Desirably, at least 30, 50, or 80 wt. % of the total ethylene oxide repeat units are in oxyalkenyl blocks (segments of the polymer) of 500 to 10,000 number average molecular weight. In another embodiment, the blocks have a number average molecular weight of 500 to 5,000 and in yet another embodiment from 500 to 3,000 g/mole. Lower molecular weight blocks of alkylene oxide type oligomers may be present for other purposes in the polyurethane. For the purpose of this definition, a block or segment is defined as a portion of the hydrophilic polymer that is derived from oxyalkylene chain or condensation polymerizations and is therefore entirely repeat units characteristic of oxyalkylene polymerization rather than urethane reactions, vinyl polymerization, or polyester type condensation reactions. The molecular weights of these PEO blocks or segments would be derived from and highly correlate with the molecular weight of the poly(alkylene oxide) chains used to make the hydrophilic polymer.
It is desirable that the hydrophilic polymer be added in amounts from about 2 to about 40 parts by weight per one hundred parts by weight of the base polymer (vinyl chloride, urethane, or acrylate), and in one embodiment from about 5 to about 35 parts by weight and in a second embodiment from about 5 to about 25 or 30 parts by weight.
In one embodiment, (particularly when the hydrophilic polymer is added as a dispersion in water) using side-chain poly(ethylene oxide) is preferred. In that embodiment, desirably as least 5, 10, 15, 25, 35, 50 or 80 weight percent of the total ethylene oxide repeating units are in side-chains, as opposed to terminal poly(ethylene oxide) or in chain poly(ethylene oxide) in the hydrophilic polymer. In another embodiment, using side-chain and/or terminal poly(ethylene oxide) is preferred. In that embodiment, desirably as least 5, 10, 15, 25, 35, 50 or 80 weight percent of the total ethylene oxide repeating units are in combined side-chains and terminal chains, as opposed to in chain poly(ethylene oxide) in the hydrophilic polymer.
Apart from PEO, other hydrophilic polymers can impart moisture permeability by incorporating them into the side chain, main chain and/or end groups of a polymer. Suitable monomers resulting in hydrophilic polymers are listed in the section below titled “Polar and Hydrophilic Monomers and Components”. The routes of their incorporation include “living” or controlled polymerizations and are known to those skilled in the art.
Topology/architecture of the subject of the present invention when utilizing poly(ethylene oxide) as the hydrophilic segments can be schematically represented by the following charts:
where:
Hydrophilic Polyurethanes. Hydrophilic polyurethane for the purpose of this application includes a) poly(ethylene oxide) in one or more possible forms and b) 2 or more linkages characterized as derived from reacting an isocyanate group with a hydroxyl or amine group. In some embodiment, it is desirable that only one end of the poly(ethylene oxide) is directly attached to the polymer and the other end is more mobile and is in essence dangling from the polymer (these were earlier described as side-chain or terminal PEO). A polyurethane can be branched such that it has more than two termini, making it possible to have more than two terminal poly(ethylene oxide) blocks. Poly(ethylene oxide) may be manufactured such that one end of the poly(ethylene oxide) chain is not capable of chemically bonding into a polyurethane (non-reactive end) while the other (preferably distal) end of the poly(ethylene oxide) chain has two or more reactive hydroxyl or amine groups that can incorporate into the polyurethane. One such commercial material is Tegomer™ D-3403 available from Degussa-Goldschmidt. Such side-chain poly(ethylene oxide) and its effect on moisture vapor transmission are shown in U.S. Pat. No. 6,897,281 hereby incorporated by reference for its description of side-chain poly(ethylene oxide). Others sources or synthesis methods for poly(ethylene oxide) containing species that form lateral side-chains from the polyurethane backbone as disclosed in WO 2003/046036. Incorporation of such poly(ethylene oxide) with one distal non-reactive end and two proximal reactive groups at the other PEO end results in a side-chain poly(ethylene oxide) along the polyurethane backbone.
A preferred process for making such hydrophilic polyurethanes with side chain poly(ethylene oxide) chains comprises: reacting to form an isocyanate-terminated prepolymer (1) at least one polyisocyanate having an average of about two or more isocyanate groups; (2) at least one active hydrogen-containing compound comprising (a) poly(alkylene oxide) in an amount comprising about 12 wt. % to about 80 wt. % of said polyurethane, and at least about 50 wt. % of said alkylene oxide groups are ethylene oxide. It is also preferred in one embodiment that poly(alkylene oxide) main-chain (in-chain) units be present. It is also preferred in one embodiment that at least one other active hydrogen-containing compound not containing poly(alkylene oxide) side-chain units be present in said hydrophilic polyurethane. It is desirable in one embodiment that at least one compound having at least one crosslinkable functional group is present in said hydrophilic polyurethane.
The isocyanate-terminated prepolymer can be diluted and dispersed into water, dispersed in a volatile solvent, polymerized (further chain extended) in plasticizer solution or water, or diluted with a suitable plasticizer. It can then be further functionalized, chain extended, or remain isocyanate terminated. The lower molecular weight of the prepolymer versus a chain extended polyurethane would make it a lower viscosity material in plasticizer or solvent facilitating subsequent simple blending with vinyl chloride polymer. In some applications, residual isocyanate groups may help adhesion to substrates, but residual isocyanate groups might be involved in non-intended chemical reactions if exposed to moisture or other isocyanate reactive materials during storage. This might cause changes in the molecular weight and other properties of the polyurethane. The isocyanate terminated prepolymer (optionally end capped or chain extended) can be mixed with the vinyl chloride monomer or polymer, and optionally plasticizer and/or solvent.
Alternatively, to using the isocyanate prepolymer as a low molecular weight hydrophilic material, it may be dispersed in water, and optionally chain extended by reaction with at least one of water, inorganic or organic polyamine having an average of about 2 or more primary and/or secondary amine groups, polyalcohols, or combinations thereof (this is further explained in U.S. Pat. No. 6,897,281). Thereafter, the dispersion in water can be mixed with vinyl chloride monomer or vinyl chloride polymer and that material can be further processed into one of the embodiments of this disclosure.
Additional embodiments for processes for making the hydrophilic polyurethane include making similar prepolymers or chain extended polyurethane using ethylene oxide polymers that are monoalkoxy and monohydroxy terminated or if the stoicheometry of the reaction groups is controlled to prevent chain extension the isocyanate groups can be reacted with di or polyhydroxy polymers and thereby be terminated. Using monohydroxyl terminated or polyhydroxyl terminated polymers are less likely to result in side chain poly(ethylene oxide) but do result in hydrophilic polyurethanes that promote moisture vapor transmission. In one embodiment, it is preferred to use relatively small amounts of urethane forming components (di and poly-isocyanates and optionally in-chain polyols and amines) to create a polyfunctional isocyanate functionalized polymer core that can be capped with several mono-hydroxyl functionalized poly(ethylene oxide) segments. In another embodiment, a tri or higher functionality isocyanate could be directly reacted with several hydroxyl or amine terminated oligomers containing poly(ethylene oxide) segments. The hydroxyl or amine terminated oligomers could contain other repeating units, such as propylene oxide, or could comprise mostly ethylene oxide repeating units. The hydroxyl or amine terminated oligomers could be alkoxy capped if chain extension or chain coupling reactions were to be avoided. These would create a relatively low molecular weight hydrophilic urethane prepolymers that could be used as the hydrophilic polymer.
At this point, it would be desirable to discuss molecular weights of the hydrophilic polyurethane. If the hydrophilic polyurethane is to be dissolved or highly swollen with a solvent or plasticizer, it would be desirable that the number average molecular weight is from about 1,000 to about 300,000, in another embodiment from about 3,000 to about 100,000, and in still another embodiment from about 5,000 to about 50,000. At these molecular weights, the solution of 5, 10, or 20 wt. % polyurethane in solvent or plasticizer would be fluid even if rather resistant to flow. At higher molecular weights for the hydrophilic polymer the solids content of the blend could be adjusted downward with plasticizers or solvents to facilitate intermixing with the vinyl chloride polymer. Any addition of solvent or plasticizer to the hydrophilic polymer would carry that solvent or plasticizer into the blend with vinyl chloride polymer.
If the hydrophilic polyurethane can be added to the vinyl chloride polymer as a dispersion in water, the intrinsic viscosity of the polyurethane has little effect on the viscosity of the dispersion, as the viscosity of the continuous phase (rather than the dispersed phase) of the dispersion is primarily controlling the viscosity of the dispersion. Thus, a hydrophilic polyurethane of low to very high molecular weight can be utilized when the hydrophilic polyurethane is added to the vinyl chloride polymer as a dispersion of polyurethane in water. Once the hydrophilic polyurethane is added and homogeneously distributed throughout the poly(vinyl chloride), the effect of molecular weight of the hydrophilic polymer is thought to be insignificant on the measured moisture vapor transmission rate.
Optionally, when making dispersions of polyurethane in water, at least one organic solvent or plasticizer is introduced into the reaction mixture at any time during prepolymer formation, and before the prepolymer is optionally dispersed in water. These can reduce the viscosity of the phase to be dispersed, making it easier to shear the polyurethane into very small particles in the dispersed phase. Organic solvents and or plasticizer can also be added to the prepolymer and/or low molecular weight polymer in bulk, plasticized form or in a finished dispersion in water. Vapor permeation properties can further be augmented by the use of hydrophilic plasticizers such as citrates and triethylene glycol esters.
Before continuing with discussion of the preferred process, it is noted that other processes can also be used to manufacture the hydrophilic polyurethanes of the present invention, including but not limited to the following:
Dispersing a prepolymer by shear forces with emulsifiers (external emulsifiers, such as surfactants, or internal emulsifiers having anionic, nonionic and/or cationic groups as part of or pendant to the polyurethane backbone, and/or as end groups on the polyurethane backbone).
Melt dispersion process. An isocyanate-terminated prepolymer is formed, and then reacted with an excess of ammonia or urea to form a low molecular weight oligomer having terminal urea or biuret groups. This oligomer is dispersed in water and chain extended by methylolation of the biuret groups with formaldehyde.
Ketazine and ketimine processes. Hydrazines or diamines are reacted with ketones to form ketazines or ketimines. These are added to a prepolymer, and remain inert to the isocyanate. As the prepolymer is dispersed in water, the hydrazine or diamine is liberated, and chain extension takes place as the dispersion is taking place.
Continuous process polymerization. An isocyanate-terminated prepolymer is formed. This prepolymer is pumped through high shear mixing head(s) and dispersed into water and then chain extended at said mixing head(s), or dispersed and chain extended simultaneously at said mixing head(s). This is accomplished by multiple streams consisting of prepolymer (or neutralized prepolymer), optional neutralizing agent, water, and optional chain extender and/or surfactant.
Reverse feed process. Water and optional neutralizing agent(s) and/or extender amine(s) are charged to the prepolymer under agitation. The prepolymer can be neutralized before water and/or diamine chain extender is added.
With respect to the hydrophilic polyurethane, they can be more accurately described as poly(urethane/urea)s if the active hydrogen-containing compounds are polyols and polyamines. It is well understood by those skilled in the art that “polyurethanes” is a generic term used to describe polymers obtained by reacting isocyanates with at least one hydroxyl-containing compound, amine-containing compound, or mixture thereof. It also is well understood by those skilled in the art that polyurethanes also include allophanate, biuret, carbodiimide, oxazolidone, isocyanurate, uretdione, and other linkages in addition to urethane and urea linkages.
Polyisocyanates. Suitable polyisocyanates have an average of about two or more isocyanate groups, preferably an average of about two to about four isocyanate groups and include aliphatic, cycloaliphatic, araliphatic, and aromatic polyisocyanates, used alone or in mixtures of two or more. Diisocyanates are more preferred.
Specific examples of suitable aliphatic polyisocyanates include alpha, omega-alkylene diisocyanates having from 5 to 20 carbon atoms, such as hexamethylene-1,6-diisocyanate, 1,12-dodecane diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, 2,4,4-trimethyl-hexamethylene diisocyanate, 2-methyl-1,5-pentamethylene diisocyanate, and the like. Polyisocyanates having fewer than 5 carbon atoms can be used but are less preferred because of their high volatility and toxicity. In one embodiment, desirably at least 50 wt. % of the isocyanates incorporated into said hydrophilic polyurethane were aliphatic or cycloaliphatic di and/or polyisocyanates.
Specific examples of suitable cycloaliphatic polyisocyanates include dicyclohexylmethane diisocyanate, (commercially available as Desmodur™ W from Bayer Corporation), isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-bis-(isocyanatomethyl)cyclohexane, and the like. Preferred cycloaliphatic polyisocyanates include dicyclohexylmethane diisocyanate and isophorone diisocyanate.
Specific examples of suitable araliphatic polyisocyanates include m-tetramethyl xylylene diisocyanate, p-tetramethyl xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,3-xylylene diisocyanate, and the like.
Examples of suitable aromatic polyisocyanates include 4,4′-diphenylmethylene diisocyanate, toluene diisocyanate, their isomers, naphthalene diisocyanate, and the like. Preferred aromatic polyisocyanates are toluene diisocyanate and 4,4′-diphenylmethylene diisocyanate. In one embodiment, it is desirable to have at least 50 wt. % of the isocyanates incorporated into said hydrophilic polyurethane being aromatic di and/or polyisocyanates.
Active Hydrogen-containing Compounds. The term “active hydrogen-containing” refers to compounds that are a source of active hydrogen and that can react with isocyanate groups via the following reaction: —NCO+H—X→—NH—C(═O)—X. Examples of suitable active hydrogen-containing compounds include but are not limited to polyols, polythiols and polyamines.
As used herein, the term “alkylene oxide” includes both alkylene oxides and substituted alkylene oxides having 2 to 10 carbon atoms. The active hydrogen-containing compounds used in this invention have poly(alkylene oxide), optionally as side chains, sufficient in amount to comprise about 12 wt. % to about 80 wt. %, preferably about 15 wt. % to about 60 wt. %, and more preferably about 20 wt. % to about 50 wt. %, of poly(alkylene oxide) units in the final polyurethane on a dry weight basis. In one embodiment, at least about 50 wt. %, preferably at least about 70 wt. %, and more preferably at least about 90 wt. % of the poly(alkylene oxide), optionally in side-chain units, comprise poly(ethylene oxide), and the remainder of the poly(alkylene oxide) units can comprise alkylene oxide and substituted alkylene oxide units having from 3 to about 10 carbon atoms, such as propylene oxide, tetramethylene oxide, butylene oxides, epichlorohydrin, epibromohydrin, allyl glycidyl ether, styrene oxide, and the like, and mixtures thereof.
In one embodiment, (particularly where the hydrophilic polyurethane is dispersed in water before combining with the vinyl chloride polymer) preferably such active hydrogen-containing compounds provide less than about 25 wt. %, more preferably less than about 15 wt. % and most preferably less than about 5 wt. % poly(ethylene oxide) units in the backbone (main chain) based upon the dry weight of final polyurethane, since such main-chain poly(ethylene oxide) units tend to cause swelling of polyurethane particles in the waterborne polyurethane dispersions and also contribute to lower in-use tensile strength of articles made from the polyurethane dispersion. Mixtures of active hydrogen-containing compounds having such poly(alkylene oxide) side chains can be used with active hydrogen-containing compounds not having such side chains. Another source of active hydrogen-containing molecules that have ethylene oxide repeat units are polyalkylene glycols sold as surface active agents (surfactants) or dispersants by companies such as BASF, Huntsman, Ethox, etc. These can be functionalized with various groups such as alkyl phenols, fatty alcohols, oxo alcohol, Guerbet alcohol, etc.
In one embodiment, the polyurethanes of the present invention also have reacted therein at least one active hydrogen-containing compound not having said side chains and typically ranging widely in molecular weight from about 50 to about 10,000 grams/mole, preferably about 200 to about 6,000 grams/mole, and more preferably about 300 to about 3,000 grams/mole. Suitable active-hydrogen containing compounds not having said side chains include any of the amines and polyols described hereafter.
The term “polyol” denotes any molecular weight product having an average of about two or more hydroxyl groups per molecule. Examples of such polyols that can be used in the present invention include higher polymeric polyols such as polyester polyols and polyether polyols, as well as polyhydroxy polyester amides, hydroxyl-containing polycaprolactones, hydroxyl-containing acrylic interpolymers, hydroxyl-containing epoxides, polyhydroxy polycarbonates, polyhydroxy polyacetals, polyhydroxy polythioethers, polysiloxane polyols, ethoxylated polysiloxane polyols, polybutadiene polyols and hydrogenated polybutadiene polyols, polyacrylate polyols, halogenated polyesters and polyethers, and the like, and mixtures thereof. The polyester polyols, polyether polyols, polycarbonate polyols, polysiloxane polyols, and ethoxylated polysiloxane polyols are preferred.
Poly(alkylene oxide) side chains can be incorporated into such polyols by methods well known to those skilled in the art. For example, active hydrogen-containing compounds having poly(alkylene oxide) side chains include diols having poly(ethylene oxide) side chains such as those described in U.S. Pat. No. 3,905,929 (incorporated herein by reference in its entirety). Further, U.S. Pat. No. 5,700,867 (incorporated herein by reference in its entirety) teaches methods for incorporation of poly(ethylene oxide) side chains at col. 4, line 35 to col. 5, line 45.
The polyester polyols typically are esterification products prepared by the reaction of organic polycarboxylic acids or their anhydrides with a stoichiometric excess of a diol. Examples of suitable polyols for use in the reaction include poly (glycol adipate)s, poly(ethylene terephthalate) polyols, polycaprolactone polyols, orthophthalic polyols, sulfonated and phosphonated polyols, and the like, and mixtures thereof.
The diols used in making the polyester polyols include alkylene glycols, e.g., ethylene glycol, 1,2- and 1,3-propylene glycols, 1,2-, 1,3-, 1,4-, and 2,3-butylene glycols, hexane diols, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, and other glycols such as bisphenol-A, cyclohexane diol, cyclohexane dimethanol (1,4-bis-hydroxymethylcyclohexane), 2-methyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, dimerate diol, hydroxylated bisphenols, polyether glycols, halogenated diols, and the like, and mixtures thereof. Preferred diols include ethylene glycol, diethylene glycol, butylene glycol, hexane diol, and neopentyl glycol.
Suitable carboxylic acids used in making the polyester polyols include dicarboxylic acids and tricarboxylic acids and anhydrides, e.g., maleic acid, maleic anhydride, succinic acid, glutaric acid, glutaric anhydride, adipic acid, suberic acid, pimelic acid, azelaic acid, sebacic acid, chlorendic acid, 1,2,4-butane-tricarboxylic acid, phthalic acid, the isomers of phthalic acid, phthalic anhydride, fumaric acid, dimeric fatty acids such as oleic acid, and the like, and mixtures thereof. Preferred polycarboxylic acids used in making the polyester polyols include aliphatic or aromatic dibasic acids.
The preferred polyester polyol is a diol. Preferred polyester diols include poly(butanediol adipate); hexane diol adipic acid and isophthalic acid polyesters such as hexane adipate isophthalate polyester; hexane diol neopentyl glycol adipic acid polyester diols, e.g., Piothane 67-3000 HNA (Panolam Industries) and Piothane 67-1000 HNA; as well as propylene glycol maleic anyhydride adipic acid polyester diols, e.g., Piothane 50-1000 PMA; and hexane diol neopentyl glycol fumaric acid polyester diols, e.g., Piothane 67-500 HNF. Other preferred polyester diols include Rucoflex® S1015-35, S1040-35, and S-1040-110 (Bayer Corporation).
Polyether diols may be substituted in whole or in part for the polyester diols. Polyether polyols are obtained in known manner by the reaction of (A) the starting compounds that contain reactive hydrogen atoms, such as water or the diols set forth for preparing the polyester polyols, and (B) alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin, and the like, and mixtures thereof. Preferred polyethers include poly(propylene glycol), polytetrahydrofuran, and copolymers of ethylene oxide with propylene oxide.
Polycarbonates include those obtained from the reaction of (A) diols such 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, and the like, and mixtures thereof with (B) diarylcarbonates, such as diphenylcarbonate, or phosgene.
Polyacetals include the compounds that can be prepared from the reaction of (A) aldehydes, such as formaldehyde and the like, and (B) glycols such as diethylene glycol, triethylene glycol, ethoxylated 4,4′-dihydroxy-diphenyldimethylmethane, 1,6-hexanediol, and the like. Polyacetals can also be prepared by the polymerization of cyclic acetals.
The aforementioned diols useful in making polyester polyols can also be used as additional reactants to prepare the isocyanate terminated prepolymer.
Instead of a long-chain polyol, a long-chain amine may also be used to prepare the isocyanate-terminated prepolymer. Suitable long-chain amines include polyester amides and polyamides, such as the predominantly linear condensates obtained from reaction of (A) polybasic saturated and unsaturated carboxylic acids or their anyhydrides, and (B) polyvalent saturated or unsaturated aminoalcohols, diamines, polyamines, and the like, and mixtures thereof.
Diamines and polyamines are among the preferred compounds useful in preparing the aforesaid polyester amides and polyamides. Suitable diamines and polyamines include 1,2-diaminoethane, 1,6-diaminohexane, 2-methyl-1,5-pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 1,12-diaminododecane, 2-aminoethanol, 2-[(2-aminoethyl)amino]-ethanol, piperazine, 2,5-dimethylpiperazine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (isophorone diamine or IPDA), bis-(4-aminocyclohexyl)-methane, bis-(4-amino-3-methyl-cyclohexyl)-methane, 1,4-diaminocyclohexane, 1,2-propylenediamine, hydrazine, urea, amino acid hydrazides, hydrazides of semicarbazidocarboxylic acids, bis-hydrazides and bis-semicarbazides, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, N,N,N-tris-(2-aminoethyl)amine, N-(2-piperazinoethyl)-ethylene diamine, N,N′-bis-(2-aminoethyl)-piperazine, N,N,N′-tris-(2-aminoethyl)ethylene diamine, N-[N-(2-aminoethyl)-2-aminoethyl]-N′-(2-aminoethyl)-piperazine, N-(2-aminoethyl)-N′-(2-piperazinoethyl)-ethylene diamine, N,N-bis-(2-aminoethyl)-N-(2-piperazinoethyl)amine, N,N-bis-(2-piperazinoethyl)-amine, polyethylene imines, iminobispropylamine, guanidine, melamine, N-(2-aminoethyl)-1,3-propane diamine, 3,3′-diaminobenzidine, 2,4,6-triaminopyrimidine, polyoxypropylene amines, tetrapropylenepentamine, tripropylenetetramine, N,N-bis-(6-aminohexyl)amine, N,N′-bis-(3-aminopropyl)ethylene diamine, and 2,4-bis-(4′-aminobenzyl)-aniline, and the like, and mixtures thereof. Preferred diamines and polyamines include 1-amino-3-aminomethyl-3,5,5-trimethyl-cyclohexane (isophorone diamine or IPDA), his-(4-aminocyclohexyl)-methane, bis-(4-amino-3-methylcyclohexyl)-methane, ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, and pentaethylene hexamine, and the like, and mixtures thereof. Other suitable diamines and polyamines include Jeffamine® D-2000 and D-4000, which are amine-terminated polypropylene glycols, differing only by molecular weight, and which are available from Huntsman Chemical Company.
Prepolymer Ratios of Isocyanate to Active Hydrogen. The ratio of isocyanate to active hydrogen in the prepolymer typically ranges from about 0.5:1 to about 3.0:1. In embodiments where further chain extension or residual isocyanate groups are desired, preferably from about 1.5:1 to about 2.1:1, and more preferably from about 1.7:1 to about 2:1. In embodiments where an excess of hydroxyl chains ends are anticipated and molecular weight is limited thereby the NCO:OH ratio would be below 1:1 such as from 0.5:1 to about 1:1. In embodiments where the amount of monofunction PEO is controlled to limit molecular weight the ratio could be about 1:1 or 0.8:1 to 1.2:1.
Catalysts. The formation of the isocyanate-terminated prepolymer may be achieved without the use of a catalyst. However, a catalyst is preferred in some instances. Examples of suitable catalysts include stannous octoate, dibutyl tin dilaurate, and tertiary amine compounds such as triethylamine and bis-(dimethylaminoethyl)ether, morpholine compounds such as β,β′-dimorpholinodiethyl ether, bismuth carboxylates, zinc bismuth carboxylates, iron(III)chloride, potassium octoate, potassium acetate, and DABCO® (diazabicyclo[2.2.2]octane), from Air Products. The preferred catalyst is a mixture of 2-ethylhexanoic acid and stannous octoate, e.g., FASCAT® 2003 from Elf Atochem North America. The amount of catalyst used is typically from about 5 to about 200 parts per million of the total weight of prepolymer reactants.
Prepolymer Neutralization. Optional neutralization of the prepolymer having pendant carboxyl groups converts the carboxyl groups to carboxylate anions, thus having a water-dispersibility enhancing effect (if the prepolymer is to be dispersed in water). Suitable neutralizing agents include tertiary amines, metal hydroxides, ammonium hydroxide, phosphines, and other agents well known to those skilled in the art. Tertiary amines and ammonium hydroxide are preferred, such as triethyl amine (TEA), dimethyl ethanolamine (DMEA), N-methyl morpholine, and the like, and mixtures thereof. It is recognized that primary or secondary amines may be used in place of tertiary amines, if they are sufficiently hindered to avoid interfering with the chain extension process.
Chain Extenders. As a chain extender, at least one of water, inorganic or organic polyamine having an average of about 2 or more primary and/or secondary amine groups, polyalcohols, ureas, or combinations thereof is suitable for use in the present invention. Suitable organic amines for use as a chain extender include diethylene triamine (DETA), ethylene diamine (EDA), meta-xylylenediamine (MXDA), aminoethyl ethanolamine (AEEA), 2-methyl pentane diamine, and the like, and mixtures thereof. Also suitable for practice in the present invention are propylene diamine, butylene diamine, hexamethylene diamine, cyclohexylene diamine, phenylene diamine, tolylene diamine, 3,3-dichlorobenzidene, 4,4′-methylene-his-(2-chloroaniline), 3,3-dichloro-4,4-diamino diphenylmethane, sulfonated primary and/or secondary amines, and the like, and mixtures thereof. Suitable inorganic amines include hydrazine, substituted hydrazines, and hydrazine reaction products, and the like, and mixtures thereof. Suitable polyalcohols include those having from 2 to 12 carbon atoms, preferably from 2 to 8 carbon atoms, such as ethylene glycol, diethylene glycol, neopentyl glycol, butanediols, hexanediol, and the like, and mixtures thereof. Suitable ureas include urea and its derivatives, and the like, and mixtures thereof. Hydrazine is preferred and is most preferably used as a solution in water. The amount of chain extender typically ranges from about 0.5 to about 0.95 equivalents based on available isocyanate.
Polymer Branching. A degree of branching of the polyurethane may be beneficial, but is not required. This degree of branching may be accomplished during the prepolymer step or the optional chain extension step. For branching during the optional chain extension step, the chain extender DETA is preferred, but other amines having an average of about two or more primary and/or secondary amine groups may also be used. For branching during the prepolymer step, it is preferred that trimethylol propane (TMP) and other polyols having an average of about two or more hydroxyl groups be used. The branching monomers can be present in amounts up to about 5 wt. % of the polymer backbone.
Plasticizers. The hydrophilic polyurethane of the present invention can be prepared in the presence of a plasticizer to lower the viscosity and to help facilitate homogenous mixing with the vinyl chloride polymer. The plasticizer can be added at any time during prepolymer preparation, prior to dispersion in water, or to the polyurethane during or after its manufacture. Plasticizers well known to the art can be selected for use in this invention according to parameters such as compatibility with the particular polyurethane and desired properties of the final composition. A list of plasticizers for such hydrophilic polyurethanes is available in U.S. Pat. No. 6,576,702 in column 7, line 40 through column 10, line 15. Flame retardant plasticizers (which are desirable in PVC exposed to sparks or flames) are taught in column 9, line 55, through column 10, line 8. Plasticizers which aid moisture permeability are taught in U.S. Pat. No. 6,498,210 and WO 2004/014445.
The Hydrophilic Vinyl Polymer. The vinyl polymers of this invention are any polymer which can be formed by chain growth polymerization of ethylenically unsaturated monomers. Examples of such monomers include, but are not limited to, the following:
Free-Radical Polymerizable Monomers. Examples of free radical polymerizable monomers which are useful in forming the vinyl polymers of this invention include acrylic esters, methacrylic esters, unsaturated nitrites, styrenic monomers, vinyl esters, vinyl ethers, conjugated dienes, olefins, halogenated, allyl and other monomers, and mixtures thereof.
Specific examples include acrylic esters and methacrylic acid esters having the formula I:
wherein R1 is hydrogen or a methyl group, and R2 contains about 1 to 100 carbon atoms, more typically 1 to 50 or 1 to 25 carbon atoms, and optionally, also one or more sulfur, nitrogen, phosphorus, silicon, halogen or oxygen atoms. Examples of suitable (meth)acrylate esters include methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate, n-butyl(meth)acrylate, isopropyl(meth)acrylate, isobutyl(meth)acrylate, tert-butyl(meth)acrylate, n-amyl(meth)acrylate, n-hexyl(meth)acrylate, isoamyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate, N,N-diethylaminoethyl(meth)acrylate, t-butylaminoethyl(meth)acrylate, 2-sulfoethyl(meth)acrylate, trifluoroethyl(meth)acrylate, glycidyl(meth)acrylate, benzyl(meth)acrylate, allyl(meth)acrylate, 2-n-butoxyethyl(meth)acrylate, 2-chloroethyl(meth)acrylate, sec-butyl-(meth)acrylate, tert-butyl(meth)acrylate, 2-ethylbutyl(meth)acrylate, cinnamyl(meth)acrylate, crotyl(meth)acrylate, cyclohexyl(meth)acrylate, cyclopentyl(meth)acrylate, 2-ethoxyethyl(meth)acrylate, furfuryl(meth)acrylate, hexafluoroisopropyl(meth)acrylate, methallyl(meth)acrylate, 3-methoxybutyl(meth)acrylate, 2-methoxybutyl(meth)acrylate, 2-nitro-2-methylpropyl(meth)acrylate, n-octyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, 2-phenoxyethyl(meth)acrylate, 2-phenylethyl(meth)acrylate, phenyl(meth)acrylate, propargyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, norbornyl(meth)acrylate, acrylamide and its derivatives, and tetrahydropyranyl(meth)acrylate. Mixtures of acrylic and methacrylic acid esters may be used. The polymerized acrylic and methacrylic acid esters typically may comprise up to 99, 98, 95 or 90 wt % of the vinyl polymer.
Unsaturated nitrile monomers include acrylonitrile or an alkyl derivative thereof, the alkyl preferably having from 1 to 4 carbon atoms, such as acrylonitrile, methacrylonitrile, and the like. Also suitable are unsaturated monomers containing a cyano group such as those having the formula II:
CH2═C(R)CO(O)CH2CH2CN (II)
wherein R is H or CnH2n+1 and n is 1 to 4 carbon atoms. Other examples of unsaturated nitrile monomers include CH2═C(CN)2, CH3—CH═CH—CN, NC—CH═CH—CN, 4-pentenenitrile, 3-methyl-4-pentenenitrile, 5-hexenenitrile, 4-vinyl-benzonitrile, 4-allyl-benzonitrile, 4-vinyl-cyclohexanecarbonitrile, 4-cyanocyclohexene, and the like. Mixtures of the unsaturated nitriles may also be used. Acrylonitrile and methacrylonitrile are preferred. The polymerized unsaturated nitrile monomers typically may comprise no more than about 60 wt. %, more typically no more than 20%, 15 wt. %, 10 wt. %, 5 wt. % or 3 wt. % of the vinyl polymer.
The “styreneic monomers” useful in preparing the hydrophilic polymer(s) of this invention may be defined as monomers containing a carbon-carbon double bond in the alpha-position to an aromatic ring. Examples of suitable styrenic monomers include styrene, alpha-methylstyrene, tertiary butylstyrene, ortho, meta, and para-methylstyrene, ortho-, meta- and para-ethylstyrene, o-methyl-p-isopropylstyrene, p-chlorostyrene, p-bromostyrene, o,p-dichlorostyrene, o,p-dibromostyrene, ortho-, meta- and para-methoxystyrene, indene and its derivatives, vinylnaphthalene, diverse vinyl(alkyl-naphthalenes) and vinyl(halonaphthalenes) and mixtures thereof, acenaphthylene, diphenylethylene, and vinyl anthracene. Mixtures of styrenic monomers also may be used. Styrene and alpha-methylstyrene are preferred. The polymerized styrenic monomers typically may comprise no more than about 99 wt. %, more typically no more than 80%, 60 wt. %, 40 wt. %, 20 wt. %, 10 wt. % or 5 wt. % of the vinyl polymer. Copolymers of at least one styrenic monomer and at least one maleic anhydride monomer are anticipated as being desirable hydrophilic polymers in this application after being functionalized with poly(ethylene oxide) segments. Such polymers known in the art and are used as polymeric dispersants for pigments.
Vinyl ester monomers derived from carboxylic acids containing 1 to 100, more typically 1 to 50 or 1 to 25, carbon atoms also may be useful in preparing the vinyl polymer of the present invention. Examples of such vinyl ester monomers include vinyl acetate, vinyl propionate, vinyl hexanoate, vinyl 2-ethylhexanoate, vinyl octanoate, vinyl pelargonate, vinyl caproate, neo esters of vinyl alcohol, vinyl laurate, and the like, as well as mixtures thereof. The polymerized vinyl ester monomers typically may comprise from 0 wt. % to about 99.5 wt. % of the vinyl polymer of the present invention.
Vinyl ethers may be useful in preparing the vinyl polymer of the present invention. Examples of vinyl ethers include methyl-, ethyl-, butyl, iso-butyl vinyl ethers and the like. The polymerized vinyl ether monomers typically may comprise from 0 wt. % to about 99 wt. %, preferably from 0 wt. % to about 50 wt. %, of the vinyl polymer of the present invention.
Conjugated diene monomers containing 4 to 12 carbon atoms, and preferably from 4 to 6 carbon atoms, also may be useful in preparing the vinyl polymer of the present invention. Examples of such conjugated diene monomers include butadiene, isoprene, pentadiene, and like, as well as mixtures thereof. Butadiene is more preferred.
Olefin monomers containing 2 to 100 carbon atoms, and preferably from 2 to about 10 carbon atoms, also may be useful in preparing the vinyl polymer of the present invention. Examples of such olefins include ethylene, propylene, butylenes, isobutylene, hexe-1-ene, oct-1-ene and like, as well as mixtures thereof. Cyclic olefins may also be used such as vinyl cyclohexane, cyclopentene, cyclohexene, cyclooctadiene, norbornene, norbornadiene, pinene and like. The polymerized olefins typically may comprise from 0 wt. % to about 99 wt. %, from 0 wt. % to about 70 wt. %, from 0 wt. % to about 30 wt. %, or from 0 wt. % to about 10 wt. %, of the vinyl polymer of the present invention.
Apart from halogen-containing monomers mentioned above, other fluorine, chlorine, bromine, and iodine-containing monomers also may be useful in preparing the vinyl polymer of the present invention. They may contain 2 to 100 carbon atoms and at least one halogen atom. Examples of such monomers include vinyl fluoride, vinyl chloride, vinyl bromide, vinylidene fluoride, vinylidene chloride, halogenated (meth)acrylic and styrenic monomers, allyl chloride and like, as well as mixtures thereof. Vinyl chloride, vinyl acetate, methyl acrylate, ethyl acrylate and methyl methacrylate are preferred.
Polar and Hydrophilic Monomers. Another group of monomers which are useful in preparing the hydrophilic vinyl polymers of the present invention are polar monomers such as hydroxyalkyl(meth)acrylates, (meth)acrylamides and substituted (meth)acrylamides, sodium styrene sulfonate and sodium vinyl sulfonate, N-vinyl-2-pyrrolidone, N-vinyl caprolactam, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, (4-hydroxymethylcyclohexyl)-methyl(meth)acrylate, acrolein, diacetone (meth)acrylamide, 1-(2-((2-hydroxy-3-(2-propenyloxy)propyl)amino)ethyl)-2-imidazolidinone, N-methylol(meth)acrylamide, diallyl phosphate, Sipomer® WAM, WAM II (from Rhodia) and other urido-containing monomers, dimethylaminoethyl(meth)acrylate, and dimethylaminopropyl(meth)acrylamide, acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, acrylamido(2-methyl propane sulfonic acid), and vinyl phosphonic acid. Mixtures of polar monomers also may be used.
Hydrophilic Monomers and Components. Hydrophilic components (i.e., monomers, chain transfer agents, initiators) have at least one hydrophilic, ionic or potentially ionic group is optionally included in the polymer to assist dispersion of the polymer, thereby enhancing the stability of the dispersions so made. Typically, this is done by incorporating a compound hearing at least one hydrophilic group or a group that can be made hydrophilic (e.g., by chemical modifications such as neutralization or deblocking) into the polymer chain. These compounds may be of a nonionic, anionic, cationic or zwitterionic nature or the combination thereof.
For example, anionic groups such as carboxylate, sulfate, sulfonate, phosphate, and phosphonate can be incorporated into the polymer in an inactive form and subsequently activated by a salt-forming compound, such as ammonia, organic amines and alkali metal hydroxides. Other hydrophilic compounds can also be reacted into the polymer backbone, including lateral or terminal hydrophilic ethylene oxide, the organic amines and polyamine/polyimines previously described as chain extenders for polyurethanes, pyrrolidone or ureido units.
Hydrophilic compounds of particular interest are those which can incorporate acid groups into the polymer such as ethylenically unsaturated monomers having at least one carboxylic acid group, and preferably one or two carboxylic acid groups. Examples of such monomers include acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, vinyl acetic acid, mesaconic acid, citraconic acid, 2-acrylamido-2-methylpropanesulfonic acid, styrene sulfonic acid, 2-sulfoethyl(meth)acrylate, alkali metal salts of the above acids and amine or ammonium salts thereof such as sodium allyl sulfonate, sodium 1-allyloxy-2-hydroxypropane sulfonate (COPS 1), 2-acrylamido-2-methyl propane sulfonate (AMPS), sodium dodecyl allyl sulfosuccinate (TREM-LF40), sodium methallyl sulfonate, sodium styrene sulfonate, sodium vinyl sulfonate, sodium vinyl phosphonate, sodium sulfoethyl methacrylate. The polymerized ethylenically unsaturated monomers having at least one acid group typically may comprise no more than about 50 wt. %, more typically no more than about 40 wt. %, 30 wt. %, 20 wt. %, 10 wt. %, 9 wt. %, 8 wt. % or even 5 wt. % of the vinyl polymer of the present invention. When used, they are normally present in amounts of about 1 wt. % or more, more typically about 2 wt. %, 3 wt. %, 4 wt. %, 5 wt. % 6 wt. %, 7 wt. %, 8 wt. %, 9 wt. % or 10 wt. % or more. The acid-containing monomer and polymers can be esterified with poly(ethylene oxide) containing segments to produce side-chains and/or amidized with amine terminated PEO containing chains.
PEO-Containing Compounds. Another preferred group of hydrophilic compounds are the reactive macromers of alkylene oxides having at least one functional group capable of free-radical transformation. Such macromers, which are well known in the prior art, have the formula
X—(Y—O)n—Z (IV):
wherein Y is a straight or branched chain alkyl radical having 1 to 6 carbon atoms, preferably 2 to 4 carbon atoms, X is a functional group capable of free-radical transformation, such as acrylate, which may be represented by the formula H2C═CHC(O)O—, methacrylate, which may be represented by the formula H2C═C(CH3)C(O)O—, allyl ether, which may be represented by the formula H2C═CHCH2O—, vinyl ether, which may be represented by the formula H2C═CHO—, vinylbenzyl, vinylsulfonic ester, which may be represented by the formula H2C═CHSO3—, or mercaptan, Z is H, CmH2m+1, phosphate, or the same as X, and m is 1 to 8, preferably 1 to 3. “n” may vary to achieve the desired molecular weight (number average) set forth below. Z is preferably H or methyl. X is preferably acrylate or methacrylate. Examples of suitable reactive monomers include methoxy poly(ethylene oxide)(meth)acrylate (also known as methoxypolyethylene glycol methacrylate or “MePEGMA”), methoxy poly(ethylene oxide)allyl ether, poly(ethylene oxide)allyl ether, butoxy poly(ethylene oxide)(meth)acrylate, p-vinylbenzyl terminated poly(ethylene oxide), poly(ethylene oxide)di(meth)acrylate, poly(ethylene oxide)thiol, poly(ethylene oxide)maleimide, poly(ethylene oxide)vinylsulfone, ethyl triglycol methacrylate, and the like. Mixtures of the reactive macromers may also be used. Preferred reactive macromers include methoxy poly(ethylene oxide)(meth)acrylate, methoxy poly(ethylene oxide)allyl ether, and poly(ethylene oxide)allyl ether. Suitable reactive macromers may have molecular weights (number average) from about 100 to about 10,000, preferably from about 100 to about 5,000, and more preferably from about 300 to about 2,000. One such polymeric additive is Bisomer™ S10W from Clariant shown in the examples, which is co-polymerizable source of nonionic polymers. Other similar side-chain monomers include Bisomer MPEG350MA=methoxy(polyethyleneglycol)methacrylate, Bisomer MPEG550MA=methoxy(polyethyleneglycol)methacrylate, Bisomer S10W=methoxy(polyethyleneglycol)methacrylate (50% in water), Bisomer S20W=methoxy(polyethyleneglycol)methacrylate (50% in water), Genagen M 750, Genagen M 1100, and Genagen M 2000; all available from Clariant.
The alkylene oxide-containing macromers typically may comprise no more than about 80 wt. %, more typically no more than about 70 wt. %, 60 wt. % 50 wt. %, 40 wt. %, or 30 wt. % of the vinyl polymer of the present invention. When used, they are normally present in amounts of at least about 5 wt. %, 10 wt. %, 15 wt. %, or 20 wt. % of the final hydrophilic vinyl polymer. Hydrophilic poly(ethylene oxide) segments may also be added to the hydrophilic polymer by post polymerization reactions between carboxylic groups such as derived from acrylic acid, epoxy groups such as from glycidyl methacrylate, and/or carboxylic groups from maleic anhydride reacted with hydroxyl and/or amine groups on a poly(ethylene oxide) segment. Such reactions are taught in U.S. Pat. Nos. 5,393,343; 5,583,183; and 5,633,298.
Hydrophilic or potentially hydrophilic groups may also be introduced into the polymer by the use of chain transfer agents such as 3-mercaptopropanoic acid, PEG thiols and like and mixtures thereof.
Compounds Having at Least One Crosslinkable Functional Group. Compounds having at least one crosslinkable functional group can also be incorporated into the vinyl polymers of the present invention, if desired. Examples of such compounds include N-methylol acrylamide (NMA), diacetone acrylamide (DAAM), acetoacetoxy ethyl methacrylate (AAEM), epoxy-containing compounds, —OH containing compounds, —COOH containing compounds, isocyanate-containing compounds (TMI), mercaptan-containing compounds, compounds containing olefinic unsaturation and the like. Mixtures can also be used.
Catalysts. Any compound capable of generating free radicals under the reaction conditions employed can be used as catalysts for vinyl polymer formation in this invention. In this regard, see, “Initiators”, Vol. 13, pp. 355-373, Kirk-Othmer, Encyclopedia of Chemical Technology, ©1981, John Wiley & Sons, New York., the disclosure of which is incorporated herein by reference. Anionic, cationic and coordination polymerization catalysts as well as various energy sources such as UV, EB, IR, X-ray can also be used.
Solution or Bulk Polymerization. Techniques for bulk polymerizing and solution polymerizing ethylenically unsaturated monomers are well known in the prior art and described, for example, in the above-noted Kirk-Othmer articles. See, also, “Initiators,” Vol. 13, pp. 355-373, Kirk-Othmer, Encyclopedia of Chemical Technology, ©1981, John Wiley & Sons, New York, the disclosures of which is also incorporated herein by reference. Any such technique can be used in making the vinyl polymers of this invention.
Polymer Neutralization. In those instances in which the vinyl polymer includes hydrophilic compounds which produce pendant carboxylic or other acid groups, these groups can be converted to carboxylate or other anions via neutralization.
Suitable neutralizing agents for this purpose include ammonium hydroxide, metal hydroxides, amines, phosphines, and other agents well known to those skilled in the art. Ammonium hydroxide is preferred. Examples of useful amines include 2-amino-2-methyl-propanol-1 (AMP-95), ethylamine, diethylamine, triethyl amine, ethanolamine, diethanolamine, triethanolamine, dimethyl ethanolamine, N-methyl diethanolamine, methylamine, dimethylamine, trimethylamine, ethylene diamine, isophorone diamine, N-methyl morpholine, urotropin, DABCO, and the like, and mixtures thereof.
Plasticizers. The vinyl polymers of this invention can be prepared in the presence of a plasticizer. The plasticizer can be added at any time during polymer preparation or dispersion or after its manufacture. Plasticizers well known to the art can be selected for use in this invention according to parameters such as compatibility with the particular vinyl polymer and desired properties of the final composition, including vapor permeability. A more detailed list of plasticizers (such as those for polyurethanes and vinyl chloride) are described elsewhere in the specification.
To the above hydrophilic polymer or the blend of hydrophilic polymer with PVC, acrylate, or urethane, optional additives such as as an electrostatic dissipating salt, a lubricant, a defoamer, a surfactant, and/or a wax could be added. Various electrostatic dissipating (ESD) salts can be utilized to further modified resistivity of the present invention such that undesirable electrostatic charges are dissipated and build up of the same is abated. The various ESD salts are desirably inorganic and include cations such as metals from groups 1 and 2 of the periodic table with various anions such as nitrates, sulfates, hydroxyls, halogens, and the like. Preferred salts are lithium compounds such as LiCl, LiNO3, LiOH, LiCF3SO3, Li2SO4, lithium(bis)trifluoromethanesulfonimide, and the like with LiNO3 being preferred. The amount of the ESD salt is such that in combination with the hydrophilic polymer, suitable surface and volume resistivities are achieved. Such amounts generally range from about 0.1 or 1.0 to about 8 or about 10 parts by weight and desirably from about 3 or to about 6 parts by weight per 100 total dry parts by weight of the hydrophilic polymer. For ease of blending, the dissipative metal salts are sometimes added in an aqueous or polar solution. The use of lithium salts either alone or in association with a solvent is described in detail in U.S. Pat. No. 6,140,405 which is hereby fully incorporated by reference.
The static dissipative polymer blends of the present invention can be utilized as a coating, article, or a product. Desired surface resistivities thereof are from about 105 to about 1012, and desirably from about 108 to about 1011 ohm/square at 12% relative humidity. Desired volume resistivities thereof are from about 104 to about 10 ohm/cm at 12% relative humidity.
Other Additives for Hydrophilic Vinyl Polymer. Other additives well known to those skilled in the art can be used to aid in preparation of the hydrophilic vinyl polymer. Such additives include stabilizers, defoamers, antioxidants (e.g., Irganox™ 1010), UV absorbers, activators, curing agents, stabilizers such as carbodiimide, colorants, neutralizing agents, thickeners, non-reactive and reactive plasticizers, coalescing agents such as di(propylene glycol)methyl ether (DPM) and PM acetate, waxes, slip and release agents, antimicrobial agents, surfactants such as ionic and nonionic surfactants (e.g., Pluronic™ F68-LF, IGEPAL™ C0630) and silicone surfactants, metals, salts, antiozonants, and the like.
Blends with Other Polymers and Polymer Dispersions. The polymers of this invention can be combined with commercial polymers and polymer dispersions by methods well known to those skilled in the art. Such polymers and dispersions include those described in WIPO Publication WO 02/02657 A2, U.S. Pat. No. 4,920,176, U.S. Pat. No. 4,292,420, U.S. Pat. No. 6,020,438, U.S. Pat. No. 6,017,997, and a review article by D. P. Tate and T. W. Bethea, Encyclopedia of Polymer Science and Engineering, Vol. 2, p. 537, the disclosures of which are incorporated herein by reference.
Overview of Applications for Blend(s) of PVC. The blend of vinyl chloride polymer and hydrophilic polymer (optionally with plasticizer for the PVC or the hydrophilic polymer) of the present invention can be processed by methods well known to those skilled in the art (including blending with other polymers and materials) to make coatings and films and other articles having increased (adjustable) moisture vapor transmission rates (“MVTR”). Suitable MVTR values for hydrophilic polymer modified PVC films or coatings are typically an upright cup MVTR (ASTM E-96B) with a nominal 1 oz/yard dry coating/film weight of at least about 50 grams/m2/24 hours, preferably at least about 100 grams/m2/24 hours, and more preferably at least about 150 grains/m2/24 hours grams/m2/24 hours. Suitable MVTR for hydrophilic modified PVC films or coatings in an inverted water cup MVTR (ASTM E-96BW) of at least about 200 grams/m2/24 hours, preferably at least about 500 or 1000 grams/m2/24 hours, and more preferably at least about 2000 grams/m2/24 hours grams/m2/24 hours. The term “breathable” is used herein to denote such excellent MVTR.
Desirably, the MVTR for a film of the hydrophilic polymer (polyurethane or vinyl polymer) in an upright water cup MVTR ASTM E-96B with a nominal 1 oz/yard dry coating/film weight is at least about 200 grams/m2/24 hours, preferably at least about 400 grams/m2/24 hours, and more preferably at least about 500 or 600 grams/m2/24 hours. Suitable MVTRs for the hydrophilic polymer (polyurethane or vinyl polymer) in an inverted water cup MVTR ASTM E-96BW are at least about 200 grams/m2/24 hours, preferably at least about 500 or 1000 grams/m2/24 hours, and more preferably at least about 2000 or 3000 grams/m2/24 hours grams/m2/24 hours.
The blend of vinyl chloride polymer with hydrophilic polymer (optionally with plasticizer for the PVC or hydrophilic polymer) may be employed as a coating composition, molding composition, dipping solution, extrudable composition, adhesive, etc. It can be applied to a variety of substrates such as fibrous materials. Any fibrous material can be coated, impregnated or otherwise treated with the compositions of the present invention by methods well known to those skilled in the art, including carpets as well as textiles used in clothing, upholstery, tents, awnings, paper, felts, tarpaulins, awnings, protective clothing, gloves, mattress covers, gowns, diapers, pads, and the like. Suitable textiles include fabrics, yarns, and blends, whether woven, non-woven, or knitted, and whether natural, synthetic, or regenerated. Examples of suitable textiles include cellulose acetate, acrylics, wool, cotton, jute, linen, polyesters, polyamides, regenerated cellulose (Rayon), and the like. Examples of vinyl end products with desirable moisture vapor transmission include dipped supported and nonsupported gloves, vinyl upholstery, banners, awnings, water resistant bedding, bedding coverings, protective personal clothing, etc.
It may be applied as a dispersion in a media. It may be applied by brushing, dipping, flow coating, spraying, rolling, etc. It may contain conventional ingredients for plastic articles such as solvents, plasticizers, pigments, dyes, fillers, emulsifiers, surfactants, thickeners, rheology modifiers, heat and radiation stabilization additives, defoamers, leveling agents, anti-cratering agents, fillers, sedimentation inhibitors, U.V. absorbers, antioxidants, flame retardants, etc. It may contain other polymeric species such as additional polymers in the forms of blends, interpenetrating networks, etc.
The vinyl chloride polymer may be in the form of a latex, plastisols, or organosol. These are dispersions of PVC particles in a liquid water or organic media. In the plastisols, the liquid is an organic one that boils at a very high temperature (e.g., having very low vapor pressure at room temperature) so the plasticizer remains with the PVC during the typical lifetime of the PVC article. In the organosols, the continuous phase is a lower boiling organic liquid, which usually does not attack or plasticize the PVC particles. In organosols, the continuous phase is lower boiling point liquids which can be removed by evaporation.
In plastisols, the PVC is the base component typically arbitrarily specified as 100 parts by weight and the other components are specified per 100 parts by weight of the PVC. An extender may be present and it can be from 0 to 40 parts by weight. Heat and light stabilizers can be present in amounts up to 5 parts by weight. Filler can be absent, or present up to 100 parts by weight. Pigment can be absent, or present up to 5 or 30 parts by weight. Volatile diluents can be present up to 10 or 30 parts by weight. Other non-named additives can be present up to about 5 parts by weight. Plasticizers for plastisols or PVC in general include C3-C13 esters of benzoic, phthalic, adipic, azelaic, sebacic, trimellitic, citric, and phosphoric acid. The choice or blend of plasticizer(s) for a particular application depends on the required viscosity, gelation, and fusion characteristics of the desired plastisols and compatibility and resistance to volatilization required. Flame retardant plasticizers (which are desirable in PVC exposed to sparks or flames) are taught in U.S. Pat. No. 6,576,702 in column 9, line 55, through column 10, line 8.
Plasticizers for PVC, especially those that maximize moisture vapor permeability, are taught in U.S. Pat. No. 6,498,210 and WO 2004/014445. For example, volatilization of the plasticizer becomes a large concern in plasticized articles used in automobiles. In these applications in automobiles, volatile plasticizers can be released inside the automobile on hot summer days and fog the interior of glass surfaces. In some embodiments, it is desirable that the at least one plasticizer for the PVC is present in amounts from about 1, 2, 5, or 10 parts by weight up to 50, 80, or 150 parts by weight based on the weight of the PVC.
Flame retardation may be important in these compositions when the finished article will be near open flames, sparks or hot surfaces. Examples of such uses include clothing, personal protective gear for fire department personnel, etc. PVC inherently has some flame resistance but this can be enhanced with things like phosphate esters, such as tricresyl phosphate, optionally with antimony oxide and chlorinated paraffins.
Heat stabilizers are desirable additives in the high moisture vapor transmission blends of vinyl chloride polymer with hydrophilic polyurethane. The heat stabilizers can be any of those known to the art, including metal salts or soaps of long chain fatty acids or organotin compounds. Calcium and zinc salts are also used. Lead, barium and cadmium salts are less often used. Epoxy compounds such as an epoxidized soybean oil and condensates of epichlorohydrin and bis(4-hydroxyphenyl)dimethylmethane are sometimes used as secondary stabilizers.
Other additives include fillers, pigments, calcium carbonate, titanium dioxide, anionic surfactants and the like to assist in maintaining the dispersion and reducing viscosity. Bonding agents such as isocyanates to increase adhesion to some substrates, chemical blowing agents, such as 1,1′-azobisformamide, optionally with a zinc soap to reduce the temperature range for the mechanical foaming of the PVC. Mechanical foaming of some types of PVC compositions is also possible.
The PVC can he mixed with the hydrophilic polymer (polyurethane or vinyl polymer) with any mixing method. If the PVC is to be prepared for bulk extrusion, it may be mixed/formulated in Henchel type mixers, or ribbon blenders, or in extrusion equipment. If the PVC is to be processed as a plastisol, it may be processed in a low-speed planetary mixer, high speed mixers or dissolvers, or horizontal turbomixers. It is desirable that whatever mixing system is chosen will homogeneously mix the components. It is to be noted that the hydrophilic polymer (polyurethane or vinyl polymer) can be added to the monomers used to make the PVC, it can he blended with the PVC after polymerization but before drying, or it can be blended with a plasticizer(s) and then blended with the dry PVC or a pre-plasticized PVC. The amount of hydrophilic polymer desirably is from about 2, 3, 5, or 8 parts by weight to about 20, 30, 40, 50, or 60 parts by weight per 100 parts by weight of said vinyl chloride polymer. Larger amounts of the hydrophilic polymer are possible, but such blends might be better described as vinyl chloride polymers modifying the hydrophilic polymer.
The final blend of vinyl chloride polymer with hydrophilic polymer can be used in any application where increased moisture vapor transmission or other effects of the hydrophilic polyurethane is desirable in the final product. These include dipped vinyl gloves, dipped gloves with textile liners, wall coverings, flooring, water barriers, industrial fabric coatings, tarpaulins, awnings, waterproof canvas constructions (e.g., tents, vehicle covers, storage areas), vinyl upholstery, vinyl vehicle components (such as dashes, armrests, consoles, etc.) etc. The hydrophilic polymer of this invention also promotes improved static dissipative behavior in the PVC coatings and films.
The following examples provide illustrations of the invention. These examples are non exhaustive and are not intended to limit the scope of the invention.
The P-11 was manufactured by reacting the IPDI first with the PEG 1450 with heating optionally with catalyst, then with the TMP with heating, then with the MPEG 750 with heating, and finally the any extra IPDI is added. The DEGDB is added for viscosity control and was added when needed.
Test Methods ASTM E-96 BW (inverted water cup) and E-96B (upright water cup) Compound Preparation of Waterborne PVC/PU coatings. Each waterborne dispersion in the examples was prepared for testing by adding the amount of PVC emulsion (Vycar 577) required by the blend ratio to an 8 oz. glass jar, followed with the appropriate amount of polyurethane dispersion (Permax™ 230 polymer). This was followed by about 5 grams of a suitable associative thickener such as Printrite PM in order to create a thickened knife coatable mixture. (The actual amount of dispersion and thickener varied in a range of about 145-160 grams and about 4.5-6.0 grams respectively in order to achieve sufficient viscosity for knife coating purposes). The mixture was stirred using a Caframo RZR50 lab stirrer equipped with a 1-inch marine impeller until thickening maximized, which normally took about 10-15 minutes.
Preparation of 100% Solids PVC/PU Plastisol Compounds. Each plastisol in the examples was prepared for testing by adding approximately 150 grams of PVC plastisol to an 8 oz. glass jar, followed by adding the appropriate amount of hydrophilic polyurethane prepolymer of Table 1. The mixture was stirred using a Caframo RZR50 lab stirrer equipped with a 1-inch marine impeller until a uniform mixture was obtained, which normally took about 10-15 minutes.
Coating of 100% Solids PVC/PU Plastisol. Each coated fabric sample was prepared using an approximate 18 in.×10 in. swatch of Style 306A Filament Nylon 6,6 Semi-Dull Taffeta from Testfabrics Inc. The swatch was mounted and stretched on a pin frame having springs to apply tension to the fabric in the warp direction only. A thin coat (typically about 0.25 to 0.50 oz./yard2) of the PVC/hydrophilic PU plastisol was applied to the surface of stretched fabric using a floating/tight knife. The entire assembly (pin frame arid mounted, stretched, coated swatch) was placed in a circulating air oven at 212° F. until dry (typically about 5 to about 15 minutes). The fabric (still mounted on the pin frame) was stretched over an elevated glass plate on an aluminum pin frame. A 1-2 millimeter thickness of the PVC/hydrophilic PU plastisol mixture was applied using a Bird applicator, typically by drawing the applicator over the fabric twice. The pin frame was placed again in the 212° F. circulating air oven and dried. The dried fabric (having coating on it) was removed from the pin frame and dried/fused further for 5 minutes at 350° F. The final dried test specimen (fabric with coating) typically had about 1.5 to about 2.0 oz/yard2 of dried PVC/polyurethane coating applied.
Coating of PVC/PUD waterborne compounds. Each coated fabric sample was prepared using an approximate 18 in.×10 in. swatch of Style 306A Filament Nylon 6,6 Semi-Dull Taffeta from Testfabrics Inc. The swatch was mounted and stretched on a pin frame having springs to apply tension to the fabric in the warp direction only. A thin coat (typically about 0.15 to 0.20 oz./yard2) of the thickened PVC/polyurethane dispersion was applied to the entire available surface of stretched fabric using a floating/tight knife. The entire assembly (pin frame and mounted, stretched, coated swatch) was placed in a circulating air oven at 212° F. until dry (typically about 5 to about 15 minutes). The fabric (still mounted on the pin frame) was stretched over an elevated glass plate on an aluminum frame. A 1-2-millimeter thickness of the thickened PVC/polyurethane dispersion was applied using a Bird applicator, typically by drawing the applicator over the fabric twice. The pin frame was placed again in the 212° F. circulating air oven and dried. The dried fabric (having coating on it) was removed from the pin frame and dried further (including crosslinking when a crosslinking agent was used) for 5 minutes at 350° F. The final dried test specimen (fabric with coating) typically had about 0.5 to about 1.25 oz/yard2 of dried PVC/polyurethane coating.
The following procedure was used to measure rate of transmission of moisture vapor through a membrane (Moisture Vapor Transmission Rate or MVTR) for each of the dried, coated test specimens. A 4 oz. Ball Mason jar was filled with de-mineralized water to within ½ inch of the jar's top. The jar mouth was lightly coated with silicone grease. A 3 inch×3 inch test specimen (larger than the diameter of the jar mouth) was placed across the greased jar mouth with the coated (using the PVC/polyurethane being tested) side of the specimen facing the inside of the jar. The test specimen was locked into place across the jar mouth using a gasketed screw top lid having a circular opening. The complete assembly (jar, water, gasket, lid and test specimen) was weighed and placed in a conditioned room (about 72° F. and 50% relative humidity). A fan was used to blow air across the jar at about 500-575 linear feet per minute for the appropriate time interval (typically 24 hours). The jar was allowed to sit upright so that the test specimen was exposed to the moist atmosphere above the water inside the jar as a test of upright water cup MVTR. For inverted water cup testing, the jars were inverted onto a wire grid exposing the test sample to liquid water in the jar and the uncoated outside surface of the test specimen to the air flow. For both methods, the entire assembly was reweighed following the appropriate time interval, and moisture vapor transmission rate was calculated as grams of water lost per square meter of test specimen surface exposed to water vapor per unit of time (typically grams per square meter per 24 hours, or gms/m2/24 hr).
To a 3-liter three-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, were added 1140 grams DM water. In a nitrogen atmosphere, the water was refluxed for half-hour to remove air. While controlling reactor temperature at 100° C., the metering of the following two mixtures was started at the same time. Monomer stream consisting of 8 grams 3-mercaptopropanoic acid, 360 grams acrylic acid, and 82 grams Bisomer S10W (ethylenically unsaturated (co-polymerizable) macromer with repeating units derived from polymerizing ethylene oxide) was metered over 2 hours. Initiator stream consisting of 4 grams sodium persulfate and 31 grams DM water was metered over 3 hours. To complete polymerization, reaction mixture was kept at 100° C. for an extra 1 hour after initiator solution ran out. The obtained solution had the following properties: T.S.=26%, pH=2.1, B.V.=230 cP. Mn=17,000 g/mol, PDI=11.
The procedure of Example C was followed with the following changes. The initial reactor charge: 1140 grams DM water, 4 grams 3-mercaptopropanoic acid. The monomer stream was 8 grams 3-mercaptopropanoic acid, 320 grams acrylic acid, and 163 grams Bisomer S10W. The obtained solution had the following properties: T.S.=29%, pH=2.0, B.V.=45 cP.
The procedure of Example C was followed with the following changes. The initial reactor charge was 1140 grams DM water and 8 grams 3-mercaptopropanoic acid. The monomer stream was 12 grams 3-mercaptopropanoic acid, 280 grams acrylic acid, and 245 grams Bisomer S10W.
Basic formulations of PVC film, gloves and foam were made up with and without Permax P-11 added. The PVC film formula was mixed then cast@3 mils on release paper and gelled at 149° C.
for 2 minutes and fused at 188° C. for 2 minutes. The PVC Glove formula was mixed, then warmed to 40° C., cast onto release paper at 3mils, and then cured at 195° C. for 2 minutes.
The PVC Foam formula was mixed then cast@25 mils and cured at 204° C. for 5 minutes. Each formula was tested for Brookfield viscosity. Each foam was tested for thickness and Surface Resistivity. Each film was tested for MVTR, Tensile, Elongation, 100% Modulus, and Surface Resistivity.
The above results show that adding Permax P-11 PVC Plastisol reduces the Surface Resistivity in all cases from the E12 range to the E10 range making the film and foam examples static dissipative. Inverted MVTR values are increased from nearly 10× to 50× with the addition of Permax P-11.
Test Methods for Hydrophilic Vinyl Polymer.
The above hydrophilic hydrophilic vinyl polymers (Examples C, D, and E) could be substituted for hydrophilic polyurethane into blends with vinyl chloride polymers as were Prepolymer A and B and in the preceding vinyl chloride with polyurethane blends and similar results would be obtained.
While in accordance with the patent statutes the best mode and preferred embodiment has been set forth, the scope of the invention is not limited thereto, but rather by the scope of the attached claims. While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US08/83552 | 11/14/2008 | WO | 00 | 5/21/2010 |
| Number | Date | Country | |
|---|---|---|---|
| 60989460 | Nov 2007 | US |
