Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
  • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
  • D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D06M15/327—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated alcohols or esters thereof
  • D06M15/333—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated alcohols or esters thereof of vinyl acetate; Polyvinylalcohol
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/44—Preparation of metal salts or ammonium salts
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
  • D06M15/01—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with natural macromolecular compounds or derivatives thereof
  • D06M15/03—Polysaccharides or derivatives thereof
  • D06M15/11—Starch or derivatives thereof
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
  • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
  • D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D06M15/263—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acids; Salts or esters thereof
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M7/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made of other substances with subsequent freeing of the treated goods from the treating medium, e.g. swelling, e.g. polyolefins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2800/00—Copolymer characterised by the proportions of the comonomers expressed
  • C08F2800/20—Copolymer characterised by the proportions of the comonomers expressed as weight or mass percentages
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M2200/00—Functionality of the treatment composition and/or properties imparted to the textile material
  • D06M2200/40—Reduced friction resistance, lubricant properties; Sizing compositions

Definitions

• compositions which are particular poly(vinyl alcohol) copolymer ionomers, a process to prepare those compositions, and textile sizes based on those compositions. It also relates to sizes based on blends of those ionomers with other poly(vinyl alcohol) polymers or starches.
• the compositions are poly(vinyl alcohol) copolymers which have carboxylate salt ionomer comonomer units. Desizing sizes of these ionomers or blend sizes containing these ionomers, in either water or caustic solutions is easier than desizing sizes based on polymers or polymer blends which contain no poly(vinyl alcohol) copolymer ionomer. Discussion of Related Art
• PVA polymers Poly(vinyl alcohol) hompolymers, and certain poly(vinyl alcohol) copolymers, with comonomers such as alkyl acrylates, have been known for use as textile sizes for many years. For convenience, both will be generically referred to hereinafter as PVA polymers. When specificity requires they will be referred to as PVA homopolymers and PVA copolymers.
• PVA homopolymer includes PVA polymer derived from homopolymer poly(vinyl acetate) which has been only partially 'hydrolysed' or 'saponified', as well as that which has been 'fully' (>98%) hydrolysed.
• the terms 'fully hydrolysed PVA homopolymer' and 'partially hydrolysed PVA homopolymer' will be used if distinction is necessary. It is also possible to have fully or partially hydrolysed
• PVA polymers differ quite significantly in properties as textile sizes and in the ability of fabrics sized with them to be desized. This difference primarily depends on the degree of saponification or hydrolysis, the particular comonomer, and the comonomer content. Other factors including molecular weight and thermal history can also be important in size characteristics.
• PVA polymers are generally prepared by alcoholysis or hydrolysis of the corresponding poly(vinyl acetate) homopolymer or copolymer. Strictly, alcoholysis, carried out with a basic catalyst, leads to the corresponding alkyl acetate and the poly(vinyl alcohol) unit, and is conducted in alcohol as reaction medium. Hydrolysis, in water, generally uses larger amounts of metallic caustic base, leading to the corresponding metal acetate rather than alkyl acetate, and the poly(vinyl alcohol) unit. Formation of metal salts, i.e. acetates, has led to use of the term 'saponification' for the process, akin to formation of metal salts of fatty acids with caustic, in forming soaps.
• Fully hydrolysed PVA homopolymer is highly crystalline and strong, but because of its high crystallinity it dissolves only in hot, not cold water. Furthermore, when it is subjected to high temperatures, it can develop even higher levels of crystallinity than as prepared, resulting in polymer which is even more difficult to dissolve. Finishing mills with certain fabrics, particularly blend fabrics, tend to use a heat setting condition to relieve fiber stress. The treatment is typically carried out at temperatures which develop further crystallinity in fully hydrolysed PVA homopolymer, so that when such polymer is used as size on fabric, the treatment causes an increase in its crystallinity and a decrease in ease of subsequent desizing.
• PVA copolymers and partially hydrolysed PVA homopolymers are less crystalline, and dissolve at lower temperatures, or more rapidly at a given temperature. As a result they desize in water more readily, and are less subject to change in crystallinity and ability to be desized with fabric heat- setting treatments.
• the two types of PVAs are not identical in several respects. This is partly because the distribution of comonomer units (or units derived from them by lactonization, as discussed below) along the polymer chain is not the same as the distribution of residual acetate units along the chain after partial hydrolysis.
• Poly(vinyl alcohol) copolymers where the comonomer directly provides an acid functionality are known.
• the acid functionality may derive from a copolymerized monocarboxylic, dicarboxylic acid, or a dicarboxylic acid half ester.
• Acid functionality can result from hydrolysis of ester comonomer units, such as an alkyl acrylate or methacrylate.
• ester comonomer units such as an alkyl acrylate or methacrylate.
• the other ester units i.e., the comonomer ester units may or may not also be hydrolysed to the corresponding acid.
• the vinyl acetate ester units are far more readily hydrolysed than alkyl ester units. If the alkyl ester units are also hydrolysed, and if enough base is present, the resulting acid units may also be neutralized to become ionomer units. Under some conditions, internal trans-esterification can take place between the vinyl alcohol units resulting from hydrolysis, and the alkyl ester units, resulting in in-chain lactone units. Because both the vinyl acetate ester units, and the alkyl carboxylic acid ester units are subject to hydrolysis, and the hydrolysed alkyl ester units can be neutralized, depending on precise conditions, a large number of possible hydrolysis products are possible.
• Japanese Patent publication No. 55-44191 discloses partially saponified copolymers of vinyl acetate containing from 0.1 to 10 mole percent monoalkyl maleate for use as such a size.
• the level of saponification must be between 50 and 80 percent, or adhesion to the hydrophobic fibers is inadequate, and even cohesive behavior is disclosed as declining.
• Alkaline salts of the monocarboxylic ester PVA copolymer are specifically disclosed as part of the invention.
• the comonomer unit in the precursor polymer must be a monoalkyl maleate. Sizing solutions of the polymer are disclosed.
• Japanese Patent publication No. 60-14148 (4/11/85, layed open
• 53,134990, 11/25/78 describes a sizing material which is also a low saponified (65-90 mole percent) vinyl acetate copolymer - in this case the saponified product of a vinyl acetate/monocarboxylic acid copolymer with up to 3 mole percent acid.
• the product is again specifically useful for hydrophobic materials. More than 3 mole percent is disclosed as producing excessive hygroscopicity, lack of cohesiveness, and poorer weaving efficiency when used as a size.
• the product is produced by saponification at a low temperature in alcohol, water or aqueous alcohol, using either metal alcoholate or hydroxide, but under very specific conditions, specifically without kneading or mixing while solid product is obtained.
• Example polymers contain 0.8 mole percent acid or less, and a molar excess of base. However, there is no indication given of metal hydroxylate (ionomer) groups in the isolated saponified polymer.
• Japanese Patent publication No. 60-31844 (7/24/85 layed open 53-91995, 8/12/78) describes production of PVA copolymers containing from 0.1 to 50 mole percent of a dicarboxylic acid unit from a dicarboxylic acid monomer. It is disclosed that the polymers, produced by a special process are better than prior art acid copolymers for uses such as paper strengtheners, fiber sizing agents and adhesives.
• the special process is a solution process which allow solubility throughout the polymerization, by controlling dicarboxylic acid concentration, in conjunction with a saponification which uses two moles of alkali per mole of dicarboxylic acid plus 0.1 to 1.0 mole per mole of vinyl acetate. While there is thus a large amount of base, the disclosure specifically refers to avoiding any alkali remaining in the saponified PVA polymer. It would thus appear the saponified product does not contain metal carboxylate units.
• US Patent No. 4,747,976 discloses water soluble film pouches containing detergent for use in washing of clothes.
• the films are PVA copolymers containing ionomer units which derive from various comonomers which include methyl acrylate and methacrylate.
• the comonomer concentration in the polymer before saponification is from 2 - 6 mole percent.
• Of the comonomer units it appears that only 1 to 5 percent of them are converted to ionomer units.
• the disclosure ambiguously refers to 'converting about 1 to 5 mole percent of the comonomer to anionic comonomer'. Presumably this means the final polymer has a maximum of 5 percent of the acrylate or methacrylate units converted to anionic units, or a maximum of 0.3 mole percent anionic units in the in the final polymer.
• Desizing typically involves water washing. However desizing of particular polymers with caustic solution is also well known and has been described. The above-mentioned Japanese patent publication 60-14148, for instance, uses sodium carbonate solutions as desizing agents.
• Unmodified starches are inexpensive, but they do not generally have as good properties as PVA polymers, often flaking off the yarn when used as sizes. They do not give stable solutions, and often desizing requires use of enzymes.
• the invention concerns new sizing compositions which are improvements over those described in the above cited Hayes et al. patents.
• the sizing compositions are aqueous solutions of a polymer or polymer blends including that polymer, the polymer being a PVA copolymer ionomer having a controlled level, from 0.1 to 10 mole percent of anionic carboxylate (ionomer) units. Fabrics sized with such sizes are able to be very effectively desized compared with the known size materials.
• the present invention provides a sizing solution, comprising: a 1 - 20 weight percent aqueous polymer solution comprising, a first polymer which is from greater than 90 up to 100 percent hydrolysed, with respect to vinyl acetate ester units remaining from precursor vinyl acetate copolymer, poly(vinyl alcohol) copolymer ionomer, the copolymer ionomer having from 0.1 to 10 mole percent anionic carboxylate salt units.
• the sizing solution may further comprise: a second polymer, in an amount from 10 to 90 weight percent, based on the weight of total first and second polymer, the second polymer being a non-ionomeric poly(vinyl alcohol) polymer which is a poly(vinyl alcohol) homopolymer, or a poly(vinyl alcohol) copolymer containing up to 15 weight percent units derived from a Cl-C8-alkyl (meth)acrylate or a Cl-C3-dialkyl fumarate or maleate.
• a second polymer in an amount from 10 to 90 weight percent, based on the weight of total first and second polymer, the second polymer being a non-ionomeric poly(vinyl alcohol) polymer which is a poly(vinyl alcohol) homopolymer, or a poly(vinyl alcohol) copolymer containing up to 15 weight percent units derived from a Cl-C8-alkyl (meth)acrylate or a Cl-C3-dialky
• the size solution may further comprise, in addition to the first polymer only: a third polymer in an amount from 10 to 90 weight percent with respect to total first and third polymer, the third polymer being a starch which is a natural starch, a synthetic starch, a physically modified starch, or a chemically modified starch.
• a further aspect of the invention is a process to prepare poly( vinyl alcohol) copolymer ionomers having from 0.1 to 10 mole percent ionomer units, from corresponding poly(vinyl alcohol) copolymers containing from 0.1 to 10 mole percent of a Cl-C8-alkyl (meth)acrylate or Cl-C3-dialkyl fumarate or maleate comonomer derived units, by full or partial hydrolysis with base, of those comonomer units, in a reaction medium which either allows the poly(vinyl alcohol) copolymer starting polymer and derived ionomer to remain undissolved as a slurry, and hence capable of being isolated as a solid granular polymer, or in a reaction medium which is a solvent for the derived ionomer, leading directly to solutions useful as sizes.
• hydrolysis or saponification will be used to encompass conversion of the vinyl acetate ester units in poly(vinyl acetate) to poly(vinyl alcohol) units, even if the reaction is strictly an alcoholysis.
• hydrolysis will also be used for conversion of ester units of the alkyl or dialkyl ester comonomer units to free acid units, and for conversion of lactone units (i.e., internal ester units) to free acid units.
• lactone units i.e., internal ester units
• poly(vinyl acetate) copolymer containing the same comonomer.
• the poly(vinyl acetate) copolymer will be referred to as the 'precursor' copolymer.
• PVA copolymers ionomers are prepared from PVA copolymers with comonomer units by hydrolysis and/or only neutralization (depending whether the comonomer is an acid or alkyl ester which first has to be hydrolyzed).
• the PVA copolymer, before ionomerization, will be referred to as the 'starting' copolymer to avoid confusion with the precursor acetate copolymer.
• the polymers of the invention are referred to as poly(vinyl alcohol) copolymer ionomers, PVA copolymer ionomers or, for convenience, simply ionomers.
• PVA copolymer alone polymer without ionomer units is being referred to.
• PVA copolymer ionomer however embraces polymers which may contain both some remaining non- hydrolysed vinyl acetate units, and in addition, may especially contain remaining lactone (internal ester) units and/or remaining methyl acrylate or methacrylate ester units which have not been hydrolysed.
• ester comonomer units are subject to reactions with a hydroxyl from an adjacent vinyl alcohol unit to form lactones, and free alcohol from the ester unit.
• an original ester monomer unit may no longer exist as the same entity as was present in the precursor poly(vinyl acetate) copolymer.
• Almost complete lactonization may occur, though the extent may vary with different comonomers and hydrolysis conditions.
• the use of phrases such as PVA copolymers 'with' or 'containing' a given comonomer and the like should be understood in this context.
• Starches are polymeric and are referred to as 'polymers' in this disclosure, though of course they are significantly different types of polymers from strictly synthetic polymers such as PVA polymers.
• PVA copolymer ionomers are uniquely useful in preparing textile sizing compositions. This is because of their extraordinarily ready ability to be desized both in water and in dilute caustic solutions. They are far more readily desized that the PVA copolymer compositions of comparable comonomer content, described in US Patent 5,362,515 previously referred to. In addition, sizes based on blends of PVA copolymer ionomers with either prior art PVA polymers or starches both previously known for use as size materials, may be more readily desized than many comparable PVA polymer blends which do not contain PVA copolymer ionomer.
• the PVA copolymer ionomers are so readily desized, they will be usable at relatively low levels in blends with other PVA polymers or starches, and achieve a significant improvement in desizability, without adding any substantial disadvantages which may result from the PVA copolymer ionomer.
• the PVA copolymer ionomers can be used in low amounts, as little as 10 percent, rather than a major blend component.
• high levels of PVA copolymer ionomer may be advantageous.
• the sizes of this invention may be solutions of PVA copolymer ionomer alone, PVA copolymer ionomer and non-ionomeric PVA polymer, PVA copolymer ionomer and starch, or PVA copolymer ionomer with both non- ionomeric PVA polymer and starch.
• the PVA copolymer ionomer of this invention can be a mix of PVA copolymer ionomers each having a different composition, within the defined limits.
• non-ionomeric PVA polymer can include mixtures of non-ionomeric PVA polymer within the defined limits.
• Starch can likewise include mixtures of starches.
• the terms PVA copolymer ionomer, non-ionomeric PVA polymer and starch, as used in the claims, should be understood to include mixtures in the above sense.
• the PVA copolymer ionomers of this invention are derived from poly(vinyl acetate) copolymers with a comonomer unit which is capable of being converted to an ionomer unit.
• the vinyl acetate units in the precursor polymer are highly saponified/hydrolysed, being at least 90 % hydrolysed, preferably 95 % hydrolysed, and can be 'fully' hydrolysed.
• the ionomerization reaction using base to act on the alkyl ester units, will also act to hydrolyze remaining vinyl acetate units.
• the ionomers of this invention are, generally, highly suitable for hydrophilic fibers. However, because the level of ionomer units can be as low as 0.1 mole percent, they will also be suitable for hydrophobic fibers.
• the ionomers can be used in blends with other PVA based or starch sizes, and in blends, their utility for different fibers can be varied depending on the other component and the level of ionomer in the blend.
• the level of ionomer units can be varied from 0.1 to 10 mole percent, but is preferably from 2 to 8 mole percent.
• the effective amount of ionomer units can be varied both by varying the number of ionomer units in the PVA copolymer ionomer in the blend, and by varying the amount of the PVA copolymer ionomer in the blend.
• the most suitable composition for a fiber of given hydrophobicity or hydrophilicity can be obtained by varying the percent of ionomer units in the PVA copolymer ionomer, as well as the proportion of the PVA copolymer ionomer in the blend.
• composition variables in the PVA copolymer ionomer can be manipulated independently of the number are the molar percent of ionomer units.
• the number of methyl alkyl (meth)acrylate comonomer units (or twice the number in the case of alkyl maleate/fumarate units) in the precursor PVA copolymer can be higher than the number of ionomer units in the derived PVA copolymer ionomer, since complete hydrolysis of those ester units ('ionomerization') is not necessary.
• ester units 'ionomerization'
• unconverted alkyl ester or derived lactone units can remain. There are therefore a large array of variables within the compositions of the invention which can be adjusted to suit a given fiber.
• the PVA copolymer ionomers of this invention may be made from any PVA copolymer containing a comonomer unit which can be converted into an ionomer.
• the comonomer unit can be a free carboxylic acid or dicarboxylic acid unit, which is simply neutralized to form the corresponding ionomer. However, it is preferable to avoid free acid comonomers, and the presence of free acid.
• a far preferable method of preparing the copolymer ionomers is by preparation from PVA copolymers containing an alkyl acrylate or a dialkyl dicarboxylate, so that no free acid remains in the polymer.
• some ester units either external as acrylate or internal as lactone
• the PVA copolymer containing such a monomer will be made from the corresponding poly(vinyl acetate) copolymer.
• the molar amount of comonomer in the vinyl acetate copolymer must obviously be at least as great as the molar amount of ionomer units required in the final PVA copolymer ionomer if an alkyl ester of a monocarboxylic comonomer is used, (or half as great if a dialkyl ester of a dicarboxylic acid is used, since there are potentially two ionomer units derivable from each comonomer unit).
• the molar amount in the poly (vinyl acetate) polymer can be greater.
• the molar amount of ionomer units suitable in the finally derived PVA copolymer ionomer is from about 0.1 to about 10 % when used for a size composition. Levels above 2 percent are preferred for use as sizes. Above 10 percent, excessive water sensitivity can begin to be apparent. If an ionomer with 10 mole percent ionomer units is required, the precursor vinyl acetate copolymer must, for an alkyl monocarboxylic ester comonomer such as methyl acrylate, contain 10 mole % of that comonomer, or 5 mole percent of a dialkyl fumarate or maleate.
• the weight percent of that comonomer in the resulting PVA copolymer (calculated as that comonomer rather than weight based on any derived lactone) will be much greater than in poly(vinyl acetate) precursor copolymer, because of the lower molecular weight of the vinyl alcohol unit.
• a 90/10 weight or mole percent poly (vinyl acetate/methyl acrylate) copolymer would give a 90/10 mole or about 80/20 weight percent poly(vinyl alcohol/methyl acrylate) copolymer.
• Hydro lysis/saponification of the poly(vinyl acetate) copolymer either partially or fully to the corresponding poly vinyl alcohol copolymer, e.g., preferably poly(vinyl acetate)/methyl acrylate to poly(vinyl alcohol)/methyl acrylate.
• the degree of hydrolysis should be above 90 percent and can approach 100 percent to the extent that this is achievable. Typically 99 to 99.8 percent is achievable. Preferably the degree of hydrolysis is above 95 percent.
• step 3 conversion to ionomer could be carried out without isolation of PVA polymer, so that it is possible to have a combined process which combines poly(vinyl acetate) copolymer preparation, hydrolysis, and ionomerization, without ever isolating either the poly(vinyl acetate) copolymer, or the PVA copolymer. Even the resulting PVA copolymer ionomer may be made directly into size solution without its isolation as polymer.
• the process which is part of the present invention is concerned only with the step of converting granular PVA copolymer into PVA copolymer ionomer. This is referred to as step 3.
• step 1 Typical preparation of such poly(vinyl acetate) copolymers, (i.e., step 1) and their hydrolysis is given in U.S. Patent No. 3,689,469 which describes laboratory scale preparations, and U.S.4,900,335 which describes a continuous process for such polymerizations, for copolymers with up to 10 mole percent alkyl (meth)acrylate.
• step 1 Typical preparation of such poly(vinyl acetate) copolymers, (i.e., step 1) and their hydrolysis is given in U.S. Patent No. 3,689,469 which describes laboratory scale preparations, and U.S.4,900,335 which describes a continuous process for such polymerizations, for copolymers with up to 10 mole percent alkyl (meth)acrylate.
• the amounts of monomer in the feed are adjusted for different levels required in the polymer, and for their different reactivities.
• Methacrylates are more reactive than acrylates, but both are far more reactive than vinyl acetate, so that typically they are completely reacted, while less reactive vinyl acetate has to be stripped off, and would be recycled in a commercial continuous process.
• Dialkyl maleates are considerably less reactive.
• Saponfication/hydrolysis of poly(vinyl acetate) polymers and copolymers, and isolation of the resulting PVA copolymer as a powder, is a standard procedure, well known in the art.
• the PVA copolymer is typically isolated as a granular powder.
• the preferred process of this invention to prepare PVA copolymer ionomer is that of converting granular PVA copolymer containing 0.1 to 10 moles of a Cl-C8-alkyl (meth)acrylate or Cl-C3-dialkyl dimaleate or difumarate to PVA copolymer ionomer containing from 0.1 to 10 mole percent anionic carboxylate units.
• This process itself may be carried out in differing ways. Further, after preparation, the polymer may be isolated as a solid material or converted directly to a size solution. While the limits of comonomer in the ionomer and the starting PVA copolymer are the same, the amount of ionomerization need not, and normally will not be complete.
• the number of ionomer units may well be only a low percentage of the original comonomer units in the starting copolymer. For instance if only 1 percent of comonomer units in a PVA copolymer with 10 percent comonomer is converted to ionomer, there will still be 0.1 percent ionomer units, which is the bottom of the limit for ionomer units in the ionomer for use in the sizes of this invention.
• conditions used, as described in the examples below convert an estimated 20 to 70 percent of the comonomer units to ionomer units. However, an analysis which determines this precisely on any of the ionomers has not been carried out.
• the PVA copolymer is mixed with a liquid reaction medium and reacted with an appropriate base, which must be somewhat soluble in the reaction medium, for a suitable time at a suitable temperature.
• the reaction medium may be chosen either to ensure that the PVA copolymer as well as the resulting PVA copolymer ionomer remains mostly undissolved, so that the ionomer may be readily isolated.
• the reaction medium may be chosen so that the PVA copolymer ionomer can be readily dissolved, to form a size solution directly from the reactant mixture. With such a reaction medium, the starting PVA copolymer is also likely to be somewhat soluble in the medium.
• the former method uses a reaction medium which is a near non- solvent for the PVA copolymer and even less of a solvent for the PVA copolymer ionomer formed.
• This process is referred to here as a slurry process.
• the reaction medium must not dissolve more than 5 percent of either the starting PVA copolymer, or the resultant PVA copolymer ionomer. However, it must dissolve at least 0.001 weight percent of base material.
• Reaction mediums for this slurry process include C1-C3 aliphatic alcohols such as methanol, ethanol and propanol, lower alkyl ketones such as acetone, methyl ethyl ketone, and mixtures of these with some water, to the extent the solubility limits are not exceeded. Methanol, and ethanol, optionally with water, are preferred.
• the slurry may contain anywhere from 1 to 90 percent solids, though 5 to 40 percent is preferred, and 10 to 30 percent most preferred.
• the latter method uses a reaction medium which is a solvent for the PVA copolymer ionomer formed, and may be a partial solvent for the starting PVA copolymer. While it must be a solvent for the ionomer, it may be necessary to heat the reaction product to from a solution, but it must remain in solution on cooling.
• This process is referred to here as a solution process.
• the preferred reaction medium is water, though small amounts of lower alcohols are allowable provided the PVA copolymer ionomer remains soluble in it
• the as-formed solution may have a concentration of from 0.1 to 90 weight percent of the formed PVA copolymer ionomer in the liquid medium, preferably from 5 to 40 percent, and most preferably from 5 to 20 percent.
• the order of addition may vary.
• the polymer may be added to the base already in solution in the reaction medium, or solid base or a solution of the base in an appropriate solvent may be added to the PVA copolymer/reaction medium mixture.
• Suitable bases include alkali metal hydroxides, alkaline earth metal hydroxides, and quaternary ammonium hydroxides.
• the preferred bases are sodium and potassium hydroxides.
• the amount of the basic material required depends on the basic material and the amount and rate of conversion to ionomer desired. Typically, while a stoichiometric amount, relative to the amount of alkyl ester units desired to be converted to ionomer may be sufficient, more rapid reaction will occur with an excess.
• the amount of base may be from 0.1 to 20 moles per 100 moles of monomer-derived units in the starting polymer, but no more than twice the number of moles of comonomer-derived units (or lactone units derived therefrom) in the starting polymer.
• a starting polymer with 5 mole percent comonomer should employ no more than 10 moles of base for an amount of polymer which 'contains' (i.e.,has polymerized within it) 5 moles of comonomer.
• 20 moles of base is the maximum amount for an amount of polymer which contains 100 moles of monomer and hence 10 moles of comonomer.
• the rate of conversion from PVA copolymer to PVA copolymer ionomer will be a complex function of the exact chemical nature of the PVA copolymer, its amount in the reaction mixture, the reaction medium, the amount and exact nature of the base used, the reaction temperature and the reaction time.
• IR IR
• PVA copolymer ionomer could be isolated as dry granular material, blended with other polymeric size materials, and the dry product blend shipped to fabric producers.
• the PVA copolymer ionomer could be made into a blend size solution with other PVA polymers or starches, without ever isolating the PVA copolymer ionomer.
• an elevated temperature typically an elevated temperature will be needed. The time and temperature required to form a solution will depend on the actual composition, but can readily be determined by trial and error.
• Total concentration of polymer in the size solutions should be 1 to 20 weight percent, preferably 4 to 12 weight percent.
• the sizing solution may incorporate other materials typically found in sizing compositions. Such materials may include waxy-type lubricants, defoaming surfactants, and other surfactants. A skilled artisan will be able to judge what concentration size solution to use to achieve his desired size add-on level, and what additives are best suited to his operations.
• Free carboxylic acid should preferably not be present in the poly(vinyl acetate copolymers, the poly( vinyl alcohol) copolymers or in the derived PVA ionomers, but free acid is not excluded. Small amounts of acid may remain or be present in any of these.
• Rate or ease of water solubility (which will relate to desize sensitivity) of PVA copolymer ionomers will depend on the reduction in crystallinity due to increasing number of comonomer units, the net decrease in polarity with increasing levels of relatively non-polar comonomer units (usually as lactone units) not converted to ionomer units, and the increased rate of water solubility due to the polar ionomer units present. Any PVA copolymer ionomer can be expected to have a water solubility or sensitivity which is a balance due to the interplay of these factors.
• All the ester comonomers and the lactone ring they can form, will be less polar and hence less water sensitive than vinyl alcohol units but ionomer units will generally be more sensitive.
• the most water sensitive PVA copolymer ionomers within the bounds of the invention will in general be the most readily desized polymers. In some sizing situations, such polymers will be suitable sizes, but in others they may be too water sensitive. However, such highly desizable compositions may be the best ones to use in blends, since lower amounts may be needed to obtain a given level of desizability.
• PVA ionomers will have great versatility in that they can be designed to have a varying and controllable degree of water sensitivity and desizability based on the above factors. It will be within the skill of the artisan, based on trial an error, to explore the large palate of blend sizes which blends of this invention provide, to optimize any particular desired characteristics.
• Caustic desizing can aid in desizing copolymers, as has been noted.
• PVA copolymer ionomers in general desize very much more rapidly in water than the PVA copolymers from which they derive, since they contain the highly soluble ionomer groups.
• Caustic desizing also appears to aid in desizing PVA copolymer ionomers.
• PVA copolymer ionomers are that they can be desized more rapidly, without resorting to caustic desizing than a PVA copolymer with comparable level of comonomer. If caustic desizing is used, caustic solutions can be very dilute, such as about 0.001 weight percent, particularly if somewhat elevated temperatures are used to desize, though concentrations up to as high as 10 percent are possible.
• caustic desizing may be advantageous, though the concept of blending such copolymers with PVA copolymer ionomers has, as its basis, to provide an immediate desizing advantage even in water.
• water may be favored, since any increase in saponification due to caustic will increase crystallinity due to an increased percent of vinyl alcohol units, and hence decrease desizability.
• excess caustic will have to be subsequently washed off, so that higher concentration caustic than is adequate should be avoided.
• a suitable concentration for the desizing caustic solution and a suitable temperature for desizing can be readily determined when it has been decided how rapidly and how completely desizing is required.
• the emphasis may be on the most rapid desizing for economic reasons. Or the emphasis may be on as low temperature desizing as possible because the material is somewhat temperature sensitive. Usually, almost complete desizing is required. There will not be just one desizing condition suitable, but a range of alternatives.
• suitable caustic materials include any of the alkali metal hydroxides or carbonates , i.e. sodium, potassium or lithium, with sodium hydroxide being preferred. In some mills however, conditions may necessitate milder desizing. When this is the case, water desizing or desizing with carbonates can be used, and adjustments made in concentration and time and temperature of desizing.
• the yarns which can advantageously employ the sizes of this invention are any conventional yarn, either from spun fiber or filament assemblages or other weavable structures, and may be hydrophilic such as cotton or hydrophobic such as nylon or polyester or from hydrophilic/hydrophobic combinations. Some finishing operations on (woven) textiles or even knitted fabrics can also advantageously employ the sizes of this invention.
• the PVA copolymer ionomers of this invention may have a 4% solution viscosity from 1 to 60 centipoise. Preferably they should have a viscosity between 3 and 25 centipoise . It is within the skill of the artisan to determine the optimum polymer viscosity, polymer size concentration, and addon level for the particular yarn, fabric and weaving conditions he is using.
• Prior art PVA polymers in the PVA copolymer ionomer/PVA polymer blends of this invention may be any PVA homopolymer or PVA copolymer previously known for use as size or blends of such prior art polymer with PVA copolymer ionomer. This includes both fully and partially hydrolysed homopolymer, and PVA copolymers with comonomer selected from the group consisting of alkyl methacrylates, alkyl acrylates, dialkyl fumarates and dialkyl maleates, wherein the alkyl group contains from 1 to 8 carbon atoms.
• Partially hydrolysed non-ionomeric PVA in the blends may be from 50 to 98 % hydrolysed, but will preferably by above 80 % hydrolysed.
• the starches which can advantageously have blended with them the PVA copolymer ionomers to improve their ability to be desized (and, in general, to improve their behavior as sizes) include natural starches, synthetic starches and some chemically modified starches. There are some starch derived materials which have been so modified that they are far removed in properties and ability to be desized, and are not particularly advantageously blended with the PVA copolymer ionomers. Some modified starches for instance are already fairly readily desized and/or have properties far removed from natural starches. Indeed such materials may already be so modified that their modification alone may serve a similar purpose of improving sizing behavior and ability to be desized, and blending with the PVA copolymer ionomers of the invention provides only a modest additional advantage. Generally however, the PVA ionomers are more readily desized than the majority of available starches.
• the starches which are blended advantageously with the PVA copolymer ionomers of this invention are preferably natural starches or synthetic starches which have not been modified or have been modified to only a small extent.
• Natural starches are carbohydrates of natural vegetable origin which are commonly considered to be composed mainly of amylose and/or amylopectin. Specific examples of naturally-occurring starches include those of corn, wheat, potato, sorghum, rice, bean, cassava, sago, tapioca, bracken, lotus, water chestnut, and the like. These are the starches which are the preferred size materials of the invention because they will be substantially upgraded in their ability to be desized, and because in general, their properties as sizes are poorer than modified starches. Their main advantage is that they are relatively inexpensive.
• Examples of synthetic starches and chemically or physically modified starches include alpha starch, fractionated amylose, moist heat treated starch and the like, enzymatically modified starches such as hydrolyzate dextrin, dextrin produced by enzymatic degradation, amylose and the like, chemical degradation-modified starches such as acid-treated starch, hypochlorite-oxidized starch dialdehyde starch and the like, chemically modified starch derivatives such as esterified starches.
• chemically-modified starch derivatives include esterified starches such as starch acetate, starch succinate, starch nitrate, starch phosphate, starch urea phosphate, starch xanthate, starch acetoacetate; etherified starches such as allyl etherified starch, methyl etherifired starch, carboxymethyl etherifired starch, hydroxyethyl etherified starch, hydroxypropyl etherified starch; cationized starches such as the reaction product from starch and 2-diethylaminoethyl chloride, the reaction product from starch and 2,3-epoxypropytrimethylammonium chloride; crosslinked starches such as formaldehyde-crosslinked starch, epichlorohydrin-crosslinked starch, phosphoric acid-crosslinked starch and the like, and any mixture of any of the above or similar starches.
• esterified starches such as starch acetate, starch succinate, star
• the blend used to prepare the size solution may contain from 10 to 90 weight percent of the PVA copolymer ionomer and from 90 to 10 weight percent of the other PVA polymer or starch. Because of the extremely ready desizing of ionomers containing a high level of ionomer units, the lowest levels will be quite effective in increasing desizability.
• the PVA copolymer ionomers used in the sizes and blend sizes of this invention may also be adaptable for uses in certain film applications.
• Such films can include agricultural mulch films, biodegradable packaging films and water soluble films. They may also be adaptable for use as hot melt adhesives, binders and the like.
• PVA copolymer ionomer listed in Table 1 as C9AI is an example of the 'slurry' method of preparation of PVA copolymer ionomer from PVA copolymer. It was prepared as follows: 50 grams of PVA polymer C9A was added to a solution of 0.64 g. of sodium hydroxide in 30 grams of water and 120 grams of methanol, with stirring, to form a slurry. The slurry was stirred at room temperature, about 22°C, for 1 hour and then vacuum filtered through a fritted glass filter. The wet filtrate was dried in a vacuum oven under nitrogen, at room temperature, then overnight for about 4 hours at 80°C.
• This polymer was used extensively in desizing tests, and was the only slurry polymer so tested.
• Other slurry process PVA copolymers ionomers were prepared using the same method, but using different starting polymers and different amounts of base. The same process was also carried out on polymers not capable of forming ionomers, as controls, so the polymers could be compared.
• the polymers used, the amount of base used, and certain properties of the polymers are listed in Table IV.
• the above example of slurry ionomerization is included in the table (C9A polymer with 0.64 g NaOH). The properties are designed to illustrate the extent of ionomerization based on IR testing, and the effect this has, for different starting polymers, on solubility and solubility rate.
• Infra-red Analysis was determined on cast films.
• 10 percent solutions were prepared by dissolving at 80°C for 1 hour. Solution process prepared polymers were used directly for casting. Films were cast using a 15 mil knife gap at 52°C. allowed to dry for 30 minutes, and further dried in a vacuum over, overnight at room temperature under nitrogen, then at 80°C for 4 hours. Stripped films were stored in a desiccated box.
• IR analysis was performed on the films using a Nicolet 710 FT- IR spectrometer.
• the IR peak at 1725-1750 cm-1 is due to lactone function, i.e., the result of internal lactonization of the methyl acrylate or methyl methacrylate comonomer with hydroxyl of the vinyl alcohol. Its presence can be considered to indicate non-ionomerized units, either because conditions (e.g. control conditions of no base) could not ionomerize, or because incomplete conversion of lactone to ionomer units occurred. No attempt was made to quantify the amount of remaining lactone units. Result are expressed qualitatively.
• the IR peak at 1550-1575 cm-1 is, based on the art, attributed to the carboxylate ionomer units. The presence of small amounts of sodium acetate ash however will also cause a peak at this wave number, so that all samples, even without any ionomer units show small peaks in this region. Results are shown in Table IV. Film Dissolution Time. A further test of water solubility was carried out; in this instance time to dissolve at ambient temperatures, rather than amount soluble under specific temperature/time conditions. Films prepared as above were suspended in water with gentle stirring, and the time for complete dissolution was determined. Results are shown in Table IV. All three tests give an indication of the amount of ionomerization of any of the three copolymers tested.
• PVA copolymer ionomers used in desizing tests were all prepared by the solution process, except for C9AI.
• the solution process was used because the result of the process is a solution ready to use as a size. While the process was in essence, always the same, minor differences, in terms of whether base was added as solid or aqueous solution to polymer/liquid medium mixture (loosely a slurry, but not to be confused with the slurry process where the final polymer is always in the form of a slurry rather than a solution) or whether polymer was added to base solution, etc. were made. Table II lists the polymers used, and details of the solution process used with regard to the above minor differences are shown.
• the blend component not capable of being ionomerized was mixed with the ionomerizable polymer at ambient temperatures in the reaction medium (water, as distinct from methanol/water mixtures used in the slurry process), and both polymers were then heated to 90°C, principally to complete dissolution, but also to further ionomerize the ionomerizable polymer. Size solutions were generally clear and slightly viscous if only PVA polymers were used. When starches were part of the blends, some haziness was sometimes present, the starch being suspended rather than fully dissolved. When blend sizes were tested, the blends contained 50 weight percent of each component. Sizes tested are listed in Table II which is divided into three sections.
• the first section, Table II A lists sizes based on a single polymer.
• the second section, Table IIB is for sizes based on blends of PVA copolymers, some controls and some ionomer blends.
• the third section, Table IIC is for starch/PVA copolymer or ionomer blends.
• Sized fabric samples were prepared as follows. Approximately 2 inch by 2 inch squares of a 7 ounce, all cotton, bleached, duck fabric type 464 obtained from Test Fabrics Inc. were first weighed, then soaked in size solution for about 2 minutes at about 35 deg. C, mixing gently. Fabric weight was generally between 0.4 and 0.7 grams, and the amount of size added on between about 0.13 and 0.4 grams. The samples were then dried by placing on aluminum foil, treated with Teflon lubricant to prevent sticking, at 50 deg. C. in a convection oven for 17 +/- 1 hours. They were then cooled in a calcium sulfate desiccated box, and reweighed to determine the amount of size added on. In some cases the samples were heat-treated by placing in a convection oven at 140 deg. C. for 10 minutes.
• Desizing tests were carried out by soaking the sized fabric sample in 100 grams of the test desizing medium, (either water or caustic) for 10 minutes with gentle mixing. In some instances when water was used, the sample was further desized by soaking in another 100 grams of water for 10 minutes. In all instances when caustic was used, the sample was subsequently soaked in 100 grams of water for 10 minutes. This subsequent water treatment washes out the caustic as well as providing for slight further desizing. The desized or partially desized samples were then dried in a convection air oven at 140 deg. C. for 1 hour and then allowed to cool in a calcium sulfate desiccated box. Details, are shown in the Tables III which is divided into three sections.
• Table IIIA is for single polymer compositions (ionomers and controls), the second, Table IIIB for mixed PVA polymer compositions (ionomer and non-ionomer blends) and the third, Table IIIC for mixed PVA copolymer/starch compositions (the copolymer being either ionomer or non- ionomer.
• Table IIIC for mixed PVA copolymer/starch compositions (the copolymer being either ionomer or non- ionomer.
• the sizing tests in each of the Table III tables employs a size listed in the corresponding Table II. (e.g.,. Table IIIB and Table IIB).
• the percent desizing in the examples is considered to be an indication of the ease of complete desizing. If the value shown is less than 100%, then longer desizing times, different caustic concentration or somewhat higher temperatures would be necessary to achieve complete desizing. Double washes (i.e. equivalent to longer desizing times) produced increased desizing.
• the sized fabrics were heat treated, and some were subjected to a double water wash. Heat treating can in some instances decrease desizability, particularly in compositions which contain a high portion of partially hydrolysed PVA polymer, particularly homopolymer.
• Desizing times are deliberately short, in order to make comparisons of ease of desizing.
• Amount of desizing is listed as 'Apparent' percent size removed. This is because minor amounts of other material from the fabric is removed in desizing tests, in addition to the size, so that some values are seen to be slightly greater than 100 percent. Longer times would completely desize most samples.
• Examples 1, 2, 3, 5 and 10 show the ease of water desizing of non-ionomer PVA polymers. Partially hydrolysed homopolymer is most easily removed of these and fully hydrolysed homopolymer the least. The other three examples are for copolymers with two different levels of methyl methacrylate, and one with a high level of methyl acrylate.
• Examples 6 and 9 illustrate the effect of increasing levels of ionomerization of polymer C5M.
• Example 5 is for non-ionomerized C5M.
• the ionomers are more readily desized and the more highly ionomerized composition is more readily desized.
• Example 7 shows that for longer desizing times (twice desized), more desizing occurs, indicating complete desizing will occur with long enough desizing time.
• Example 8 shows that dilute base produces higher desize levels for the same polymer, C5M. This suggests that the ionomerized polymer of size SZ6 can be further ionomerized with base.
• Examples 1 1 and 12 are for ionomerized polymer C9A.
• Example 12 shows that an increase in desizing temperature increases the amount of desizing for ionomers.
• Example 15 shows that even ionomers are less readily desized after heat treatment (compare example 13), but that higher desize temperatures once again allow complete desizing.
• ionomers produced from PVA copolymers with a higher level of comonomer are more readily desized, and the greater the amount of ionomerization of that PVA copolymer, the greater ease of desizing. While there are non-ionomer materials which are more readily desized than some of the ionomers which have been prepared to have lower ionomer levels (i.e., from low comonomer PVA copolymers, and/or using low levels of base), ionomers provide a ready alternative to such non-ionomer PVA polymers or copolymers.
• An ionomer will require less comonomer in the PVA starting polymer for a given ease of desizing, which in many cases will be an advantage from a preparative ease of polymerization, as well as from a cost point of view. In this sense, considerably fewer ionomer units are required than non-ionomer comonomer units to allow a given ease of desizing.
• Polymer code designations summarize the nature of the composition; H for Homopolymer, C for Copolymer 88 for -88 mole % hydrolysed, M for methyl methacrylate comonomer, and A for methyl acrylate comonomer.
• All samples have a solution pH between 5 and 7. All samples have a maximum ash level of 0.7 weight percent calculated as sodium oxide, dry basis.
• Comonomer level in copolymer is listed in weight percent, calculated as non- lactonized comonomer unit in the poly(vinyl alcohol) chain and in Mole percent.
• Codes C3M, C5M, C9A number refers to weight percent comonomer.
• C9AI Ionomerized C9A.
• MMA methyl methacrylate
• MA methyl acrylate
• First line in last cell in row states the overall composition
• Composition is an 8% solution of a 1/1 mix of starch SI and polymer C5M prepared using a base concentration of 0.1 % by weight.
• Solid NaOH >C5M slurry + S 1 + 90°C/2h. The process steps were to add solid sodium hydroxide to a slurry of C5M polymer, then add starch SI, then heat to

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