Organosiloxane-containing polysaccharides

Abstract: Disclosed are a polysaccharide derivative having the structure: and a polysaccharide graft polymer having the structure: wherein Sacch- is a polysaccharide; m is zero or one; G is the residue of a polymerizable, unsaturated monomer which is bonded to the polysaccharide in an ether or ester linkage; n is greater than one; M is the residue of one or more polymerizable, unsaturated, monomer(s), at least one of which is a siloxane-containing monomer, which have been grafted to the polysaccharide by free radical polymerization; R is an organic group which is bonded to the polysaccharide by an ether or ester linkage and to the silicon by a carbon-silicon linkage; R₁ is a straight or branched C₁-C₆ alkyl or alkenyl group, or an aryl, aralkyl or alkaryl group; and R₂ and R₃ are, independently, straight or branched C₁-C₆ alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides of straight or branched C₁-C₆ alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides wherein R₂ and R₃ together form a cyclic structure of at least five members. The siloxane-containing polysaccharide derivatives and polysaccharide graft polymers are useful in glass fiber forming size compositions, in paper making and in other applications.

Description: This invention relates to polysaccharide graft polymers which contain organosiloxane substituents. These compositions are prepared by reacting a polysaccharide with a difunctional reagent which contains a siloxane group and a group which will react with a polysaccharide. The polysaccharide-reactive group of the reagent forms an ether or ester linkage with the polysaccharide, thereby attaching a reactive siloxane group to the polysaccharide. These organosiloxane-containing polysaccharides are employed in glass fiber size compositions to improve size adhesion to glass fibers, in paper-making to increase dry strength in paper. Other silicon-containing polysaccharide compositions are known. In one class of such compositions, the silane group is bonded directly to a hydroxyl group of the polysaccharide. The compositions are prepared by first hydrolyzing the siloxane functionality of the reagent to the corresponding silanol, and then reacting the silanol with starch. One member of this class of starch organosilanes forms more viscous aqueous dispersions than unmodified starches and is useful for the hydrophobation of cellulosic materials, and as binders for mineral fibers, textile additives, paper sizes and plastic fillers. See US-A-4,540,777. Other starch organosilanes are hydrophobic and free-flowing. See US-A-3,071,492. Such compositions are not useful in applications taught herein which require the presence on the polysaccharide of siloxane substituent(s) that are available for further reaction. Silicone-containing amylose films have been prepared by contacting the surface of a preformed amylose film with organo-silicon halides. See US-A-3,398,015. The silicon is bonded directly to the amylose, and the amylose-silicone films are reported to exhibit hydrophobic properties. Organosiloxane-containing polysaccharide derivatives wherein the siloxane group is available as a reactive group are taught in commonly assigned US-A-4,839,449. However, unlike the compositions disclosed herein, the derivatives disclosed in that application require a two step, dual reagent process for preparation, and the products of that process are limited to divalent aromatic group-containing, nitrogen-containing derivatives. Thus, the polymers disclosed herein offer advantages of greater flexibility, process efficiency, reagent availability and reduced costs over known organosiloxane-containing polysaccharides. The present invention also relates to a glass fiber forming size composition, comprising the organosiloxane-containing polysaccharides of this invention; and to a method for preparing glass fibers, and, in particular, to the application of the forming size to continuous filament glass fiber strands. In glass fiber production, molten glass flows or is pulled through tiny orifices or tips in a heated platinum bushing. The individual glass filaments are passed through a sizing bath, grouped into a strand, and then wound on a rapidly rotating forming tube. The size is applied to the filaments in order to bind them together, maintain the integrity of the strand during winding and unwinding, and facilitate eventual processing. The strand on the forming tube is thereafter placed in an oven to dry or is allowed to air dry to reduce the moisture content of the strand. Many different compositions have been used as glass forming sizes. Typically, the sizes have comprised aqueous dispersions of various modified and unmodified starches and oils. Numerous patents are directed to starch- or other polysaccharide-containing glass fiber size compositions. Illustrative patents include US-A-3,227,192. 3,167,468, 3,481,771, 3,664,855, 3,793,065, 3,928,666, and 4,168,345. Typical polysaccharide-containing glass fiber forming size compositions which are useful herein are disclosed in US-A-3,615,311, 4,166,872, 4,780,339, and 4,259,190. In addition, US-A-4,500,600 discloses glass fibers coated with a size containing gamma-aminopropyltriethoxysilane and a selected alkoxysilane, and a method for making such fibers. Unlike the sizes disclosed herein, the sizes according to US-A-4,500,600 do not bond a polysaccharide to the glass, and the fibers made with the Wong et al. size are designed for use in reinforced plastics. They are not suited for applications requiring significant adhesion of the size to the glass fiber. The EP-A-119 507 discloses a method for modifying a starch with organosilanes characterized by reacting the starch by close contact with an aqueous solution of the organosilane in the presence of alkalialuminate or alkali hydroxides. The EP-A-283 824 discloses polysaccharide graft polymers which comprise an acetal-containing or aldehyde-containing homopolymer or copolymer grafted to a polysaccharide base. The graft polymer is represented as Sacch-g-(M') x or Sacch-g-(M) y -(M') z , wherein M' represents a repeating unit derived from one or more ethylenically or allylically unsaturated monomers containing an acetal group -CH(OA) 2 or aldehyde group; M represents a repeating unit derived from one or more ethylenically or allylically unsaturated monomers other than the acetal-containing or aldehyde-containing monomer; x is at least 2 and y and z are at least 1; A and A' are independently a lower alkyl or A and A' together form at least a 5-membered cyclic acetal. There remains a need for new polysaccharide derivatives, especially derivatives containing silane groups which are useful in glass forming sizes and which display improved adhesion to glass. Also provided is a polysaccharide graft polymer, having the structure: obtainable by (a) optionally reacting a polysaccharide with a polymerizable, unsaturated monomer G having a polysaccharide-reactive group which forms an ether or ester linkage with the polysaccharide, and (b) grafting onto the polysaccharide or the Sacch-O-G polysaccharide derivative by free radical polymerization, one or more polymerizable, unsaturated, monomer(s) M at least one of which is a siloxane-containing monomer, to yield a polysaccharide graft polymer, wherein Sacch-O is a polysaccharide, m is zero or one, n is greater than one; and (G) and (M) are the residues of G or M, respectively. M may take the form: wherein Z is the residue of a polymerizable, unsaturated organic group which is bonded to the silicon by a carbon-silicon linkage; R 1 is a C 1 -C 6 alkyl or alkenyl group, or an aryl, aralkyl or alkaryl group; and R 2 and R 3 are, independently, C 1 -C 6 alkyl or alkenyl groups, or aryl, arakyl or alkaryl groups, or alkoxides of C 1 -C 6 alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides wherein R 2 and R 3 together form a cyclic structure of at least five members. The alkyl and alkenyl chains may be straight or branched. The organosiloxane-containing starch graft polymers herein are useful in glass forming size compositions. Thus, this invention provides a glass size composition, comprising 40-70% of an aqueous dispersion of the organosiloxane starch compositions, 15-40% of a nonionic oil, 2-8% of an emulsifier, and 5-15% of a cationic lubricant, together with a method for sizing glass fibers employing this size composition and glass fibers produced by this method. The organosiloxane-containing polysaccharides herein are also useful in paper making and in a variety of compositions in which modified polysaccharides are employed, including adhesives, thickeners, sealants, coatings, binders and films. Thus, a method of making paper employing the organosiloxane-containing polysaccharides herein and paper made thereby, are provided. Starches which may be used herein may be derived from any source, including corn, potato, sweet potato, wheat, rice, sago, tapioca, waxy maize, sorghum or high amylose corn. Starch flours also may be used. Also useful herein are the conversion products derived from any of these starches including, for example, dextrins prepared by the hydrolytic action of acid and/or heat; oxidized starches prepared by treatment with oxidants such as sodium hypochlorite; fluidity or thin-boiling starches prepared by enzyme conversion or mild acid hydrolysis; and derivatized (e.g., cationic, anionic, amphoteric, and non-ionic) starches and cross-linked starches. The starch may range from a granular form to a fully gelatinized form (i.e., cooked non-granular starch). Gums which may be used herein include polygalactomannans, which are heteropolysaccharides composed principally of long chains of 1,4-beta-D-mannopyranosyl units to which single unit side chains of alpha-D-galactopyranosyl units are joined by 1,6-linkages. Also useful herein are degraded gum products resulting from the hydrolytic action of acid, heat, shear, and/or enzyme; oxidized gums; and derivatized gums. The preferred gums include guar gum and locust bean gum because of their commercial availability. Other polysaccharides useful herein include cellulose and cellulose derivatives, especially water-soluble cellulose ethers such as alkyl and hydroxyalkyl cellulose, specifically methylcellulose, hydroxypropylmethylcellulose, hydroxybutylmethylcellulose, hydroxyethylmethylcellulose, and ethylhydroxyethylcellulose, and carboxymethylcellulose. Methods for preparing modified polysaccharides are well known to those skilled in the art and are discussed in the literature. See, for example, R. L. Whistler, Methods in Carbohydrate Chemistry, Vol. IV, 1964, pp. 279-331; R. L. Whistler et al., Starch-Chemistry and Technology, Vol. II, 1967, pp. 293-430; R. L. Davidson and N. Sittig, Water-Soluble Resins, 2nd Ed., 1968, Chapter 2; and R. L. Davidson, Handbook of Water-Soluble Gums and Resins, 1980, Chapters 3, 4, 12, and 13 directed to cellulose derivatives, Chapter 6 and 14 directed to gums, and Chapter 22 directed to starch. When starch is employed as the polysaccharide, the starch may be cooked prior to derivatization, or subsequent to derivatization. Cooking at a pH of less than 7.0 simultaneously hydrolyzes the starch siloxanes to their starch silanols, creates crosslinking between starch silanols, and solubilizes and disperses the starch silanols. Any conventional cooking procedure may be used, such as jet cooking, or cooking a slurry containing the water-soluble or water-swellable starch derivatives in a boiling water bath for 20 minutes and blowing in steam to heat the slurry to about 93°C (200°F). Granular starch reactions are typically accomplished in water at 20-50°C, preferably 35-45°C. Non-granular (cooked) starch reactions may be carried out at higher temperatures (e.g., up to 100°C) so long as excessive starch degradation is avoided. The reaction mixture is preferably agitated. Reaction time may vary from 0.5-70 hours, preferably 30-60 hours. It will depend on such factors as the amount of reagent employed, pH, temperature, scale of the reaction, and degree of substitution desired. The pH is maintained at 10-13, preferably 11-12, during the reagent addition and during the entire reaction using an organic or inorganic base, preferably sodium, potassium, or calcium hydroxide. Sodium sulfate is typically added to the reaction to reduce swelling of the granular starch; it is not used when calcium hydroxide is the base. After completion of the reaction, the excess alkali is neutralized and the pH adjusted to 4-8, preferably 7-8, using any conventional acid, preferably hydrochloric or sulfuric acid, prior to recovery of the starch. The gum reactions with the organosiloxane reagents are carried out in a two-phase reaction system comprising an aqueous solution of a water-miscible solvent and a water-soluble reagent in contact with the solid gum. The water content may vary from 10 to 60% by weight depending upon the water-miscible solvent selected. If too much water is present in the reaction system, the gum may swell and enter into solution thereby complicating the recovery and purification of the derivative. The water miscible solvent is added in the amount sufficient for the preparation of a slurry which can be agitated and pumped. The weight ratio of water-miscible solvent to gum may vary from 1:1 to 10:1, preferably from 1.5:1 to 5:1. Suitable water-miscible solvents include alkanols, glycols, cyclic and acyclic alkyl ethers, alkanones, dialkylformamide and mixtures thereof. Typical solvents include methanol, ethanol, isopropanol, secondary pentanol, ethylene glycol, acetone, methylethylketone, diethylketone, tetrahydrofuran, dioxane, and dimethylformamide. The reaction time may vary from 0.5-40 hours, preferably 3-6 hours, and the temperature may vary from 25-100°C, preferably 40-75°C. The cellulose reactions with organosiloxane reagents are conveniently carried out using the procedure of US-A-4,129,772. The cellulose or c1ellulose derivative is suspended in water and the derivatizing reagent is added thereto. Derivatization is ordinarily carried out with aqitation at temperatures of 30°C to 85°C, adding alkali to effect the reaction. At least one of the two initial phases (i.e., the suspended cellulose or cellulose derivative or the aqueous reagent solution) contains a suitable surfactant. It is important that the organic solvent used in the initial cellulose phase be immiscible with the aqueous derivatizing reagent phase, that it have a boiling point at or above the temperature of the derivatizing reaction, and that it be insensitive to alkali. Additionally, the solvent should not dissolve the cellulose derivative as it is formed, and should not participate in the derivatization reaction. The two phase procedure may be used to prepare starch or gum derivatives as well as cellulose derivatives. It also may be used to prepare derivatives containing substituents derived from different reagents without isolating the substitution product from each reagent. This multiple substitution may be accomplished by the sequential or simultaneous addition of several different reagents to the substrate-surfactant-alkali mixture. After completion of the reaction the solid polysaccharide organosiloxanes may be separated, if desired, from the reaction mixture by centrifugation or filtration. Preferably, the derivative is purified by washing in a solvent in which the reagent is soluble and the polysaccharide is not. In the case of starch derivatives, water and/or a solvent are used. In the case of the gum derivatives, a solvent is used. In the case of cellulose derivatives, an aqueous solution of water miscible solvent is used. Further washing with a more anhydrous form of the same solvent may be desired for the gum derivatives. The derivatives are then air-dried using conventional equipment, such as a vacuum, drum, flash, belt or spray-drier, or by any method of drying known in the art. If the polysaccharide is in solution when derivatized, other methods of purification (e.g., dialysis) and/or recovery (e.g., precipitation) may be used. A dry reaction process, as exemplified by US-A-4,281,109, may be used to prepare the organosiloxane derivatives herein. The reaction is typically carried out in the presence of less than 30% water and is completed in up to 2 hours at a temperature which does not exceed 200°C. The reagents typically used herein are labile at higher temperatures. The polysaccharide graft polymers of this invention are also novel compositions, having the basic structure: obtainable by (a) optionally reacting a polysaccharide with a polymerizable, unsaturated monomer G having a polysaccharide-reactive group which forms an ether or ester linkage with the polysaccharide, and (b) grafting onto the polysaccharide or the Sacch-O-G polysaccharide derivative by free radical polymerization, one or more polymerizable, unsaturated, monomer(s) M at least one of which is a siloxane-containing monomer, to yield a polysaccharide graft polymer, wherein Sacch-O is a polysaccharide, m is zero or one, n is greater than one; and (G) and (M) are the residues of G or M, respectively. In a preferred embodiment the siloxane-containing monomer, M, has the structure: wherein Z is the residue of a polymerizable, unsaturated organic group which is bonded to the silicon by a carbon-silicon linkage; R 1 is a C 1 -C 6 alkyl or alkenyl group, or an aryl, aralkyl or alkaryl group; and R 2 and R 3 are, indpendently, C 1 -C 6 alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides of C 1 -C 6 alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides wherein R 2 and R 3 together form a cyclic structure of at least five members. The alkyl and alkenyl chains may be straight or branched. While siloxane-containing monomers are an essential element of the graft polymers herein, other ethylenically unsaturated monomers(M) may also be copolymerized with the siloxane-containing monomers to form the polysaccharide graft polymers herein. Such monomers include alkyl ethers; alkyl acrylates; carboxyalkyl ethers; vinyl esters of carboxylic acids; carboxylic acids; dicarboxylic acids and their esters; olefins; and esters, amides and salts thereof. In one preferred embodiment of Structure II, Z is: and R 1 is -CH 3 and R 2 and R 3 are -OCH 3 ; or R 1 is -CH 2 CH 3 , and R 2 and R 3 are -OCH 2 CH 3 , or R 1 is -(CH 2 ) 2 CH 3 and R 2 and R 3 are -O(CH 2 ) 2 CH 3 or R 1 is -CH-(CH 3 ) 2 and R 2 and R 3 are -O-CH-(CH 3 ) 2 . In the manner illustrated below, this preferred graft polymer is prepared by, first, reacting the polysaccharide with an ethylenically or allylically unsaturated monomer, such as allyl glycidyl ether (-G-), and, second, grafting onto the polysaccharide derivative one or more polymerizable monomer(s), at least one of which is a siloxane-containing monomer (-M-) selected from the group of reagents described above for preparation of polysaccharide derivatives. The two step graft copolymerization occurs in the following manner: The practitioner will recognize that the graft polymer of Structure II also may be prepared without first reacting the polysaccharide with an ethylenically or allylically unsaturated monomer (G). In such a case, m is zero and a suitable, polymerizable, unsaturated, siloxane- containing monomer is permitted to polymerize in the presence of the polysaccharide and, optionally, in the presence of other monomers. Thus, a polymer is grafted directly onto the polysaccharide during polymerization employing conventional methods. Siloxane-containing monomers suitable for use under such conditions include methacrylamidopropyl triethoxysilane, acrylamidopropyl triethoxysilane, diallylaminopropyl trimethoxysilane, 3-(trimethoxy)silylpropyl methacrylate, and 3-(trimethoxy)silylpropyl acrylate. When preparing the polysaccharide graft polymer by the two step process illustrated above, the polysaccharide derivative may be used in any form so long as that form renders the polymer molecules available for graft polymerization. For example, in a preferred embodiment an acid-converted starch derivative (85 WF waxy maize starch allyl glycidyl ether derivative) is gelatinized by cooking in water to yield an aqueous starch dispersion. Water Fluidity (or WF) is a numerical index used to describe the amount of starch conversion, and it is inversely related to the starch viscosity. In such a dispersion, the gelatinized starch molecules are more readily accessible for graft copolymerization than are the starch molecules of an aqueous granular starch slurry. The amount of polysaccharide may vary from 5 to 95%, preferably from 20 to 50%, by weight, of the final graft polymer. Suitable monomers for preparing the siloxane-containing polysaccharides herein include any water-soluble, siloxane-containing, unsaturated compounds that are capable of free radical polymerization. Water soluble is defined herein to mean monomers which have a minimum solubility of 5% by weight in water at 25°C. Such monomers contain linkages which include acrylamido, methacrylamido, diallylamino, and acryloyl and methacryloyl ester linkages (e.g., acrylamido-propyltriethoxy silane). Various other water-soluble monomers suitable for graft polymerization with polysaccharides are known to those skilled in the art and may be employed herein. The graft polymer is prepared in a solvent or a water miscible solvent system, water-insoluble monomers may be employed. The monomers listed herein may be used in any form desired for a particular application. Thus, where a monomer is listed herein in its acid form, the salt form is meant to be included, and vice versa. Method for preparing graft polymers of polysaccharides such as starches, cellulose, and gums are well known in the literature. See, for example, Block and Graft Copolymerization , Vol. 1, R.J. Ceresa, ed., John Wiley and Sons (1973). Modification of starch by graft polymerization is described at pages 22-47 to 22-54 in Chapter 22: Starch and Its Modifications in Handbook of Water-Soluble Gums and Resins, edited by Robert L. Davidson, McGraw-Hill Book Co., New York 1980. Methods for preparing graft polymers include polymerization in water, in water-solvent mixtures, and in the dry state and may be initiated by mechanical, chemical, and irradiative techniques. The preferred method of preparing the siloxane-containing polysaccharide graft polymers is free radical polymerization. Free radical initiating methods include physical (e.g., irradiation) and chemical methods (e.g., the use of catalysts). Suitable catalysts include those of the type that establish mild oxidizing conditions at the concentrations used in the reaction mixture and are usually classified as free radical formers or sometimes called peroxidic catalysts. This class of catalysts include, among others, hydrogen peroxides, aqueous soluble organic peroxides, hydroperoxides, persulfate salts such as potassium and ammonium persulfate, ceric ions, and redox catalysts. Other free radical catalysts are those classified as water soluble "azo" catalysts, such as 2,2'-azobis(isobutyronitrile). The reaction is typically carried out until all of the monomer is consumed. Typically, the starch grafts are prepared by suspending the starch derivative in an aqueous solution, heating the suspension until the starch is gelatinized, adding the monomer, and then adding the free radical catalyst. Granular starch derivatives can also be used. They may be first heated in water at 50°C for one hour to swell before cooling to room temperature for the subsequent polymerization reaction. In addition to preparing the above graft polymers, modified siloxane-containing polysaccharides may be prepared which also contain other substituent groups, such as hydroxyalkyl groups (e.g., hydroxypropyl ether groups), carboxyalkyl ether groups (e.g., carboxymethyl), ester groups (e.g., acetate groups), and amino groups (e.g., diethylaminoethyl ether groups, or 3-(trimethylammonium chloride)-2-hydroxypropyl groups), introduced prior to or subsequent to reaction with the organosiloxane reagent, or introduced simultaneously by reaction with the organosiloxane reagent and other derivatizing reagent. In a preferred embodiment the derivative is prepared before or simultaneously with the starch organosiloxane reaction. The practitioner will recognize that reactions with reagents introducing labile ester groups should be carried out after the other derivatizations to avoid ester hydrolysis under the alkaline conditions used to prepare other derivatives. In addition to being useful in glass sizing compositions, the graft polymers are also useful in applications where conventional water-soluble or water-swellable polysaccharide derivatives are useful. For example, they are useful as coatings, adhesives,-and paper and textile additives. When used as a paper additive, the derivatives typically contain cationic or cationogenic groups in addition to the siloxane groups. These include diethylaminoethyl ether groups introduced by reaction of the polysaccharide with 2-diethylaminoethyl chloride hydrochloride (DEC) or 3-(trimethylammonium chloride)-2-hydroxypropyl ether groups introduced by reaction with 3-chloro-2-hydroxypropyl trimethylammonium chloride. The siloxane polysaccharide compositions described herein may be used in paper-making as beater additives, or as additives to the pulp at any point in the paper-making process prior to the ultimate conversion of the wet pulp into a dry web or sheet. Thus, for example, they may be added to the pulp while the latter is in the hydropulper, beater, various stock chests, or headbox. The compositions may also be sprayed onto the wet web. The siloxanes herein may be effectively used for addition to pulp prepared from any type of cellulosic fibers, synthetic fibers, or combinations thereof. Among the cellulosic materials which may be used are bleached and unbleached sulfate (kraft), bleached and unbleached sulfite, bleached and unbleached soda, neutral sulfite, semi-chemical chemiground wood, ground wood or any combination of these fibers. Fibers of the viscose rayon or regenerated cellulose type may also be used if desired. Any desired inert mineral fillers may be added to the pulp which is to be modified with the siloxanes herein. Such materials include clay, titanium dioxide, talc, calcium carbonate, calcium sulfate and diatomacous earths. Rosin or synthetic internal size may also be present if desired. The proportion of the siloxane-containing polysaccharide to be incorporated into the paper pulp may vary in accordance with the particular pulp involved and the properties desired (e.g., wet strength, temporary wet strength, or dry strength). In general, it is preferred to use 0.1-10% preferably 0.25-5% of the composition, based on the dry weight of the pulp. Within this preferred range the precise amount which is used will depend upon the type of pulp being used, the specific operating conditions, the particular end use for which the paper is intended, and the particular property to be imparted. The use of amounts greater than 5%, based on the dry weight of the pulp is not precluded, but is ordinarily unnecessary in order to achieve the desired results. It can be appreciated by the practitioner that a large number of variations may be effected in selecting the siloxane derivatizing reagents, reacting them with the polysaccharides, and utilizing the siloxane compositions as wet end additives for paper in accordance with the procedure described above without materially departing from the scope and spirit of the invention. Such variations will be evident to thos skilled in the art and are to be included within the scope of the invention. The aqueous glass fiber forming size composition ("size composition") of the present invention will typically have a solids content of 1-10%, by weight, wherein the siloxane-containing starch derivative or graft polymer is present in an amount ranging from 40-70%, and preferably 60% of the total composition. Potato and high amylose (i.e., more than 40% amylose) starches are preferred. Preferably, the size composition contains on the order of about 6% solids. The total solids should be at a level whereby the viscosity of the size dispersion is acceptable for application to the glass filaments (i.e., not exceeding 25 mPa·s (centipose) at 60°C). The nonionic oils used for the size composition may be selected from vegetable, animal, or mineral oils, and are preferably hydrogenated to reduce their flowability. The oils are preferably fatty triglycerides including, for example, hydrogenated soybean oil, hydrogenated corn oil, glycerol tristearate, hydrogenated glycerol trioleate. The oil will typically be present in the size formulation in amounts ranging from about 25% of the total composition and is preferably employed in an amount ranging from 30 to 65%, based on the total starch concentration. The size composition also preferably contains an emulsifying agent, typically present in amounts ranging from 2-8% of the total size composition. HLB values between 8 and 17 are most suitable with polyoxyalkylenesorbitans being preferred. Such emulsifiers are commercially available and include TWEEN 81® from ICI Americas Inc., which is a polyethylene derivative of sorbitan mono-oleate. TRITON® emulsifiers, polyoxyethylene derivatives of alkyl substituted phenols, obtained from Rohm and Haas are also useful herein. Cationic glass fiber lubricants used in the art to serve primarily as a lubricant prior to the time the size fibers are dried may optionally be employed in the present composition in an amount of less than about 15% of the total size composition. Such lubricants include, for example, alkyl imidazoline derivatives (i.e., the reaction product of tetra ethylene pentamine and stearic acid) and quaternary pyridinium compounds. Other conventional size composition additives including, for example, solid unctuous material such as wax, fat, or gelled oils which do not flow at application temperatures; secondary film formers such as gelatin, polyvinyl alcohol and polyacrylates; silane coupling agents; mildew preventatives; and fungicides may also be employed in the present size composition in conventional amounts. The size compositions herein may be prepared and applied to the glass fibers upon formation by conventional means. An aqueous slurry of the starch derivative is preferably cooked for a period of time to gelatinize a portion of the starch while maintaining a quantity of the starch in a swollen, unburst granular form. Thereafter, an emulsion of the nonionic oil and emulsifiers are typically added to the starch slurry along with any additional size ingredients prior to application. The size composition may then be applied at an elevated temperature (typically 55-60°C) by a suitable application method, such as by the employment of an apron type applicator or other conventional means including a padder or roll apparatus, an immersion apparatus or by spray or jet means, all of which are well known to those skilled in the art. In the examples which follow, all parts and percentages are given by weight and all temperatures are in degrees Celsius unless otherwise noted. Reagent percentages are based on dry polysaccharide. The nitrogen content of the reagents and resulting siloxanes was measured by the Kjeldahl method and is based on dry polysaccharide. The presence of organosiloxane groups was determined qualitatively by observing the viscosity increase caused by cooking an aqueous slurry of the polysaccharide derivative or graft polymer to effect hydrolysis of the siloxanes to their silanols and crosslinking between the silanols. The Brookfield viscosity test was carried out by slurrying 40 g of the polysaccharide siloxane in sufficient distilled water to give 100 g. The pH was adjusted to 5.0 or 7.0 with hydrochloric acid or to 11.0 with sodium hydroxide. The polysaccharide was dispersed and crosslinked by cooking in a boiling water bath for 20 minutes. The solids were determined and adjusted and the viscosity was measured using a #7 spindle at 20 rpms and 25°C. Example I This example describes the graft polymerization of organosiloxanes with a starch derivative. Acid-converted waxy maize starch (85 WF) was derivatized with allyl glycidyl ether using the procedure described in Example I. A total of 50 g of this starch derivative was cooked in 250 mls of water in a boiling water bath for 2 twenty minutes and then introduced into a 1000 ml Morton flask equipped with a reflux condenser, addition funnel, thermometer, and overhead stirrer. An appropriate amount of MAPS reagent (5.0 g), prepared as in Example II, Part A, above, was added to the reaction flask and the pH was adjusted to 7.0. Ammonium persulfate (0.4 g) was dissolved in 24 ml of degassed water and added to the reaction in one-third increments over three hours. The reaction was stirred for an additional four hours, inhibited with hydroquinone monoethyl ether, and then the graft polymer was precipitated from acetone. The graft polymer was air dried and analyzed for nitrogen. The reaction product contained 0.55% nitrogen, indicating that a starch graft polymer had been prepared. EXAMPLE II This example illustrates the preparation of a typical glass fiber forming size composition using the siloxane-containing starches disclosed herein. Size Composition Ingredient Percent, by weight Siloxane-containing Starch 4.9 Hydrogenated vegetable oil 1.18 Polyoxyethylene sorbitan monooleate 0.19 Tetraethylene pentamine distearate 0.22 Polyethylene glycol 1.15 Water Remainder A size composition is prepared from the above ingredients by placing all of the starch and one-half of the water in a suitable receptacle, adjusting the pH to 9.0 ± 2.0 with calcium hydroxide or other base, and cooking the starch. After cooking, the pH is lowered to 5.0 ± 2.0 with hydrochloric acid. The vegetable oil and polyoxyethylene sorbitan monooleate are then separately admixed at 65.5-76.7°C (150°-170°F), agitated until the inversion of the emulsion and preferably homogenized at 1406.2 g/mm 2 (2000 pounds per square inch). The emulsion, the tetraethylene pentamine distearate and the remainder of the water are added to the starch cook and agitated. While the starch in the above-described process is cooked in conventional equipment using conventional techniques as, for example, an open tank or receptacle at substantially atmospheric temperature and pressure, other suitable methods of cooking the starch may be used.

Claims: Claims for the following Contracting States : AT, BE, DF, FR, GB, IT, NL, SE, DK A polysaccharide graft polymer, comprising the structure Sacch-O-(G) m -(M) n-1 -M obtainable by (a) optionally reacting a polysaccharide with a polymerizable, unsaturated monomer G having a polysaccharide-reactive group which forms an ether or ester linkage with the polysaccharide, and (b) grafting onto the polysaccharide or the Sacch-O-G polysaccharide derivative by free radical polymerization, one or more polymerizable, unsaturated, monomer(s) M at least one of which is a siloxane-containing monomer, to yield a polysaccharide graft polymer, wherein Sacch-O is a polysaccharide, m is zero or one, n is greater than one; and (G) and (M) are the residues of G or M, respectively. The polmyer of Claim 1, wherein G is derived from allyl glycidyl ether; and M comprises the structure: wherein Z is the residue of a polymerizable, unsaturated organic group which is bonded to the silicon by a carbon-silicon linkage; R 1 is a straight or branched C 1 -C 6 alkyl or alkenyl group, or an aryl, aralkyl or alkaryl group; and R 2 and R 3 are, independently, straight or branched C 1 -C 6 alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides of straight or branched C 1 -C 6 alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides wherein R 2 and R 3 together form a cyclic structure of at least five members. The polymer of Claim 2, wherein is: or The polymer of Claim 3, wherein R 1 is -CH 3 and R 2 and R 3 are -OCH 3 ; or wherein R 1 is -CH 2 -CH 3 , and R 2 and R 3 are -OCH 2 -CH 3 ; or wherein R 1 is -(CH 2 ) 2 -CH 3 and R 2 and R 3 are -O(CH 2 ) 2 -CH 3 ; or wherein R 1 is -CH-(CH 3 ) 2 and R 2 and R 3 are -O-CH-(CH 3 ) 2 . A glass forming size composition, comprising an aqueous dispersion of a starch graft polymer, having the structure StO-(G) m -(M) n-1 -M obtainable by (a) optionally reacting a starch with a polymerizable, unsaturated monomer G having a polysaccharide-reactive group which forms an ether or ester linkage with the starch, and (b) grafting onto the starch or the StO-G starch derivative by free radical polymerization, one or more polymerizable, unsaturated, monomer(s) M at least one of which is a siloxane-containing monomer, to yield a starch graft polymer, wherein StO is a starch molecule, m is zero or one, n is greater than one; and (G) and (M) are the residues of G or M, respectively. The size composition of Claim 5, wherein G is derived from allyl glycidyl ether; and M comprises the structure: wherein Z is the residue of a polymerizable, unsaturated organic group which is bonded to the silicon by a carbon silicon linkage; R 1 is a straight or branched C 1 -C 6 alkyl or alkenyl group, or an aryl, aralkyl or alkaryl group; and R 2 and R 3 are, independently, straight or branched C 1 -C 6 alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides of straight or branched C 1 -C 6 alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides wherein R 2 and R 3 together form a cyclic structure of at least five members. The size composition of Claim 5 comprising 40-70% of the aqueous dispersion of the starch graft polymer; 15-40% of a nonionic oil; 2-8% of an emulsifier; and 5-15% of a cationic lubricant, with the percentages being by weight and totalling 100%. The size composition of Claim 5, wherein the starch is a high amylose corn, potato, or waxy maize starch. A method of sizing glass fibers to achieve improved adhesion of the size composition of the glass fiber, comprising applying the glass forming size composition of Claim 5 onto the fibers during formation. A method for making paper, comprising the addition to the paper stock of 0.1-10%, based on the dry weight of the pulp, of a polysaccharide graft polymer of claim 1. Paper made by the method of claim 10. Claims for the following Contracting State : ES A method of sizing glass fibers, comprising applying a glass forming size compositon onto the fibers during formation, said glass forming size composition, comprising an aqueous dispersion of a starch graft polymer having the structure StO-(G) m -(M) n-1 -M obtainable by (a) optionally reacting a starch with a polymerizable, unsaturated monomer G having a polysaccharide-reactive group which forms an ether or ester linkage with the starch, and (b) grafting onto the starch or the StO-G starch derivative by free radical polymerization, one or more polymerizable, unsaturated, monomer(s) M at least one of which is a siloxane-containing monomer, to yield a starch graft polymer, wherein StO is a starch molecule, m is zero or one, n is greater than one; and (G) and (M) are the residues of G or M, respectively. The polmyer used in the method of Claim 1, wherein G is derived from allyl glycidyl ether; and M comprises the structure: wherein Z is the residue of a polymerizable, unsaturated organic group which is bonded to the silicon by a carbon-silicon linkage; R 1 is a straight or branched C 1 -C 6 alkyl or alkenyl group, or an aryl, aralkyl or alkaryl group; and R 2 and R 3 are, independently, straight or branched C 1 -C 6 alkyl or alkenyl groups, or aryl, aralkyl or alkaryl groups, or alkoxides of straight or branched C 1 -C 6 alkyl or alkenyl groups, or aryl, aralkyl or alkaryl gorups, or alkoxides wherein R 2 and R 3 together form a cyclic structure of at least five members. The size composition used in the method of Claim 1, comprising 40-70% of the aqueous dispersion of the starch graft polymer; 15-40% of a nonionic oil; 2-8% of an emulsifier; and 5-15% of a cationic lubricant, with the percentages being by weight and totalling 100%. The size composition used in the method of Claim 1, wherein the starch is a high amylose corn, potato, or waxy maize starch. The sized glass fiber produced according to the method of Claims 1-4, characterized by improved adhesion of the size composition to the glass fiber. A method for making paper, comprising the addition to the paper stock of 0.1-10%, based on the dry weight of the pulp, of a polysaccharide graft polymer comprising the structure Sacch-O-(G) m -(M) n-1 -M obtainable by (a) optionally reacting a polysaccharide with a polymerizable, unsaturated monomer G having a polysaccharide-reactive group which forms an ether or ester linkage with the polysaccharide, and (b) grafting onto the polysaccharide or the Sacch-O-G polysaccharide derivative by free radical polymerization, one or more polymerizable, unsaturated, monomer(s) M at least one of which is a siloxane-containing monomer, to yield a polysaccharide graft polymer, wherein Sacch-O is a polysaccharide, m is zero or one, n is greater than one; and (G) and (M) are the residues of G or M, respectively. Paper made by the method of Claim 6.

Inventors: BILLMERS ROBERT L, BILLMERS, ROBERT L.
Applicants: NAT STARCH CHEM INVEST, NATIONAL STARCH AND CHEMICAL INVESTMENT HOLDING CORPORATION
Application year: 1990
Main classification: C08F251
IPC codes: C08B31, C03C25, D21H17, C08B37, C08F290, C08B11, D06M101, A61K31, C08B33, A61P9, C08B3, A61K47, D06M15