US3382142A - Cellulosic sizing compositions of rosin and polymeric reaction products - Google Patents

Description

United States Patent O 3,382,142 CELLULOSIC SIZING COMPOSITIONS F ROSIN AND POLYMERIC REACTION PRODUCTS Wiiliarn Robert Hine, Jr., Kirkwood, and Myron J. Holm, St. Louis, Mo., assignors to Monsanto Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed Aug. 23, 1965, Ser. No. 481,978 11 Claims. (Cl. 162-168) ABSTRACT OF THE DISCLOSURE This invention relates to new saponified rosin/alphaolefin maleimide-epihalohydrin polymeric reaction products which are useful in internal sizing of cellulosic webs.

This invention relates to saponified rosin/ synthetic polymer compositions which find particular utility in the internal sizing of cellulosic webs. More particularly this invention provides new saponified rosin/alpha-olefinmaleimide-epihalohydrin polymeric reaction product compositions, methods for increasing the pH range over which saponified rosin sizes may be applied to cellulose pulps to effect sizing thereof, methods for reducing the cost of a synthetic chemical internal size without substantial reduction in efficiency of the chemical size, and cellulosic webs made from pulp fibers treated with these saponified rosin/alpha-olefin-maleimide-epihalohydrin polymeric reaction products.

Rosin size compositions are generally prepared from three principal sources of rosin-gum rosin, wood rosin, and tall oil rosin. Gum rosin is obtained from the scargum of living pine trees. Wood rosin is made from the stumps of large virgin pine trees. Tall oil rosin is obtained from tall oil, a by-product of the ltraft pulping black liquor in the kraft paper making process. Rosin size is made by saponifying or neutralizing rosin with soda ash, caustic soda, potassium hydroxide, or mixtures of alkaline materials. The amount of caustic or alkaline material is often varied to give different amounts of free (unsaponified) rosin. The less free rosin, the easier the size is to emulsify. By controlling the amount of alkaline saponifying or neutralizing material used, rosin sizes can be made as liquid, paste, or dry rosin size compositions.

For various desired effects on paper special rosin size compositions are prepared, e.g., by stabilizing a rosin emulsion with casein or alpha protein. These compositions are usually those containing a high amount of free rosin. Another special size is made by saturating 0.5 percent aqueous caustic soda solution with rosin at room temperature. This rosin size is usually 100 percent neutralized.

Fortified rosin sizes have been made by reacting one or more fortifying agents such as maleic anhydride, ful'IlZtllC acid, formaldehyde, etc., with the rosin before saponification. Fortification of the rosin size makes the resuiting size composition more efiicient, less susceptible to pulp and paper making variables and more resistant to discoloration. Rosin size compositions often also contain a small amount of salt to inhibit stratification on storage.

Rosin size compositions are generally used as internal sizes for cellulose Webs and are thus mixed with the cellulose pulp used to make the paper product. In order to retain the rosin size in the paper it is usually necessary to precipitate the size in the presence of the cellulose pulp. Alum or acids, acid salts of alkaline earth metals, or alkali metal aluminates such as sodium aluminate are examples of materials which can be used as ionic precipitating agents for this purpose. Alum is much more common because of the cost advantage and because most paper making is done in acid pH conditions, which hydrolyzes the alum into Al and S0 ions and allows the Al+++ to attract the rosin size particles and pulp fibers to give sized fibers.

Sodium aluminate is used for a similar purpose in neutral or somewhat alkaline paper making operation.

Pulps used to make cellulosic web vary in sizing value because of the source of pulp used, the pulping process, the degree of pulping and bleaching, and the extent of beating of the pulp. In general the more highly bleached the pulp the harder it is to size. Pulps used for making of sized cellulosic webs include ground wood, unbleached kraft, unbleached sulfite, bleached neutral sulfite semichemical (N.S.S.C.), soda, bleached kraft, bleached sulfite, chlorine dioxide, bleached kraft, alpha, and rag pulps. In the order listed, the pulps are usually more difiicult to size.

A sized paper is more or less resistant to penetration by liquids such as water, ink suspensions, organic acids such as lactic acid, food juices, etc. Writing and fine printing papers, wrapping papers, and paper food cartons are typical examples of sized papers and paper products. To obtain the best sizing results on cellulosic paper with rosin size compositions, it is generally felt that the pH of the white water (recirculated paper making water) should be controlled to within the ranges of about. 3.9 to 6.8, preferably between about 4.5 and 5.2. Prior to this invention it was felt that as the pH rose above approximately 5.5 sizing efiiciency with rosin sizes dropped as the pH continued to rise. Persons in the paper making art are constantly seeking more efficient and more economical size compositions that can be used over a wider range of variable paper making conditions.

The purpose and object of this invention is to provide the paper making art with more efiicient methods for sizing cellulosic webs economically, with new more useful and more elficient size compositions, with new methods for sizing cellulosic pulps and webs, and with the resulting new cellulosic sized paper products.

Briefly, the purpose and object of this invention is accomplished by mixing with the aqueous pulp and fiber slurry used to make the cellulosic web (1) a rosin size, and (2) the reaction product of an epihalohydrin and a polymeric alpha-olefin/maleic imide-amine, preferably in the presence of an ionic precipitating agent, the amounts of said rosin size (1) and reaction product (2) being suflicient to eflfect sizing of the cellulosic web resulting from the treated pulp thus obtained. The resin size component (1) and the polymeric reaction product (2) may be admixed in one solution or suspension composition prior to their being applied to the wet cellulosic pulp or web, or each such component may be added or applied separately to the wet pulp or web as aqueous solutions or suspensions. In both of such methods of application the sizing efiiciency is increased. Our presently preferred method is to add the rosin size to the pulp slurry, while agitating the mixture, then add alum or other conventional ionic precipitating agent, and then add the reaction product (2). These compositions may be used to size cellulosic pulps and Webs over a wider range of acidic, neutral, and alkaline paper making conditions than is possible with rosin sizes alone.

The rosin size used as a component of the compositions of this invention may be any partially or completely neutralized or saponified gum, wood, or tall oil rosin. It may be a liquid rosin size solution or suspension, in paste form, or a dry rosin composition. The rosin size used should be one which has been sufficiently saponified or neutralized so that it can be emulsified and effectively mixed into the aqueous pulp used to make the cellulosic Web. Generally, the rosin is neutralized or saponified sufficiently to reduce the acid number thereof to below about 30 (mg. of KOH/ g. of sample). It may be simply neutralized as just described or it may be a rosin size that has been fortified by reaction of the rosin with one or more of formaldehyde, maleic anhydride, or other equivalent anhydrides, and fumaric acid. Examples of useful rosin'size compositions for the purposes of this invention are those found and described in US. Patents 2,846,328, 2,873,203, 2,934,468, 2,985,537, and 2,994,635 which are incorporated herein by reference thereto to avoid an undue lengthening of this specification.

The polymeric alpha-olefin/maleic imide-amine and epihalohydrin reaction product component (2) has sizing properties in its own right. However, it has been surprisingly found according to this invention that the combination of a rosin size with one or more of these polymeric reaction products gave substantially higher sizing effec tiveness than the rosin size alone and in many cases this increased sizing effectiveness was more than the combined but separate sizing effectiveness of the rosin size and the polymeric reaction product used at the same low concen tration, as measured by standardized ink penetration, aqueous lactic acid penescope test, and other testing methods. These results will be illustrated in the detailed examples given hereinafter. Thus, this invention provides a method for substantially increasing the effectiveness of conventional rosin sizing practices.

By combining smaller amounts of the rosin size with larger amounts of the synthetic chemical size in the treatment of aqueous cellulose pulp slurries, the sized paper obtained retains a highly sized character, normally considered attributable to the use of a larger amount of the synthetic chemical size. This invention thus provides a means for extending the usefulness of the recently developed but more expensive alpha-olefin-maleimide-epihalohydrin polymeric chemical size to use in the sizing of less expensive papers.

The polymeric alpha-olefin/maleic imide-amine and epihalohydrin reaction product component (2) is obtained by reacting an alcoholated copolymer of maleic anhydride and an alpha-olefin with an alkylene diamine or polyamine having at least one primary amino group, reacting the resulting copolymeric imide-amine with an epihalohydrin, and then acidifying the epihalohydrinated reaction product with an acid preferably hydrochloric acid. The resulting copolymer derivatives are believed to contain haloalkanol quaternary ammonium salts. These products are substantive to cellulose and readily unite therewith. The exact chemical and physical mechanism of their joinder with cellulose and sizing functionality in combination with rosin sizes is not completely known, but We know that the use of these copolymeric derivatives with rosin sizes results in the formation of webs having superior qualities.

The alpha-olefin-maleimide epihalohydrin polymeric reaction product and the rosin size may be combined in any desired proportions. The chosen proportions may be influenced by the sizing performance required of the resulting sized cellulose web, the pH at which the aqueous pulp slurry is to be sized and formed into the cellulose web, and the desired economics. There has been a recent trend in the paper making art to find methods for sizing paper under neutral or more alkaline pH conditions. This invention permits greater pH latitude to the paper maker while still allowing him to make highly sized cellulosic webs, if desired. Generally, the polymeric reaction product and the rosin size will be used in proportions to each other from about 10:90 to about 75:25 parts by weight of polymer solids of the polymeric reaction product to the saponified rosin solids in the aqueous pulp slurry.

The acidified lower molecular weight polymeric imideamine/epihalohydrin reaction products, i.e., those generally having imide viscosities below about 0.6 usually require treatment or reaction with an alkaline material shortly before or during the sizing operation to enhance or activate their sizing efiiciency. With such products it is preferred to disperse the acid stabilized size in water or other aqueous media, and to incorporate sufficient alkali, such as sodium hydroxide, or potassium hydroxide, to elevate the pH of the resulting solution to approximately 9'to 11. This is called the pretreatment step. The pretreated size is then added to a pulp slurry, and the pH of the slurry is adjusted to a lower level, preferably in the neighborhood of about 4.5 to 8.5, usually by the addition of an acid prior to sheeting of the treated pulp. Alternatively, the pH of the pretreated size can be lowered prior to addition to the pulp. With the polymeric imideamine/epihalohydrin reaction products having imide specific viscosities, of about 0.6 or higher, say up to about 3 or slightly higher, e.g., those made from C to C alkyl vinyl ether/maleic anhydride copolymers, effective sizes can be made which do not require pre-treatment with a base to get effective size results.

The alpha-olefin-maleic anhydride copolymer utilized as a starting material in the preparation of the polymeric reaction product components usually contains essentially equimolar proportions of the alpha-olefin and maleic anhydride units. However, copolymers in which the molar ratio of maleic anhydride to alpha-olefin is from about 0.90:1 to about 1.8:1 can be utilized. Copolymers having about equimolar amounts of maleic anhydride are preferred. Any available copolymers can be used, but copolymers containing very much less than about 0.9 mole of maleic anhydride per mole of alpha-olefin result in sizes that are, at best, only difiicultly soluble or dispersible in water. On the other hand, copolymers containing excessive proportions of maleic anhydride yield inferior sizes. The best sizes are made from copolymers having substantially alternating maleic anhydride-olefin moieties. The copolymers are prepared in conventional manners with or without solvents such as benzene or xylene, and using catalysts such as azobistisobutyronitrile), di-t-butyl peroxide, t-butyl perbenzoate, benzoyl peroxide, and any initiator which will be effective at from about 50- C. such as isopropyl peroxydicarbonate, tetrachlorobenzoyl peroxide and the like. The polymers employed in accordance with this invention have molecular weights of at least about 2,000, and may range up to the general neighborhood of about 200,000225,000. Molecules of excessive size introduce operational difficulties such. as a rapidly increasing tendency to gel, reduced ease of application, and the like; whereas polymers having a molecular weight substantially under 2,000 provide less satisfactory sizes. The molecular weight of the copolymer used, however, is not as critical as is the viscosity of the imideamine made therefrom, that is, the imide viscosities reflect the quality of the copolymer that was used in the manufacture of the imide. However, it is considered that the better copolymers used in this work preferably have an average molecular weight of from about 50,000 to about 115,000 and that a. polymeric imide properly made therefrom has an average molecular weight of from about 60,000 to about 150,000. Copolymers and imides made therefrom having these molecular weights are generally those made from alkyl vinyl ether/maleic anhydride copolymers and an amine mixture of N,N-dialkylarninoalkylene diamine and N-(hydroxyalkyl)alkylenediamines. Polymeric imide/epichlorohydrin reaction products made therefrom usually need no pre-treatment with an alkali prior to their application to the aqueous cellulose pulp slurries.

The term alpha-olefin and olefin are used herein as general terms to designate olefinically unsaturated compounds in which the double bond is in the alpha position, and is intended to include not only olefinically unsaturated branched and straight chained hydrocarbons such as the aliphatic olefins, e.g., ethylene, propylene, 1- butylene, l-pentylene, l-hexene, l-octene, l-nonene, 1- decene, l-dodecene, l-tridecene, l-tetradecene, 1-pentadecene, l-hexadecene, l-octadecene, l-eicosene, l-docosene, l-tetracosene, l-pentacosene, etc. and the aromatic alpha-olefin hydrocarbons such as styrene, alkyl-substituted styrenes such as vinyl toluene, the vinyl xylenes, vinyl 4-ethylbenzene, the chloro-substituted styrenes, etc. but is also intended to include other alpha-olefinically unsaturated polymerizable compounds such as alkyl vinyl ethers having about 8 or more carbon atoms in the alkyl groups, the corresponding alkenyl vinyl ethers having at least about 8 carbon atoms in the alkenyl group where sizing action is being sought. When it is desired to impart some wet or dry strength to the paper made from pulp treated with these polymeric imide-amine/epihalohydrin reaction productzrosin size compositions the alpha-olefin used may also include the shorter chained olefins hydrocarbons, alkyl vinyl ethers, as Well as such unsaturated acid monomers such as acrylic acid and methacrylic acid, vinyl esters such as the vinyl alkanoates including vinyl acetate, vinyl propionate, etc., the acrylate and methacrylate esters, such as methyl methacrylate, ethyl acrylate, and vinyl compounds such as vinyl chloride, vinyl alcohol, etc. Mixtures of the alpha-olefins may be used to react with the maleic anhydride to make the copolymer materials used for this invention, e.g., mixtures of alkyl vinyl ethers and vinyl toluene may be reacted with maleic anhydride to prepare useful copolymers. Thus the term copolymer as used herein includes the use of interpolymers of more than two monomer materials.

The alpha-olefins used in preparin the copolymers can vary considerably in molecular weight and can contain an average of from 2 to about 40 carbon atoms. The hydrocarbon alpha-olefins can be obtained from naturally occurring compounds or by the polymerization or cracking of petroleum fractions and the like. In commercial practice, they are generally mixtures containing compounds of varying length. Therefore, the number of carbon atoms attributed to such mixtures represent a weighted average rather than an absolute value. Those copolymers prepared from the lower olefins (say, up to about 12 carbon atoms) result in the formation of products which provide improved Wet and dry strength, whereas utilization of the higher olefins provides hard sizing in addition to the other advantageous properties.

Vinyl ethers, which may be used in preparing the copolymers used to prepare the polymeric reaction products, may be prepared in conventional manner by treating an alcohol with an alkali catalyst followed by reaction with acetylene. The alcohols used can be straight or branched chained, obtained from natural products or be synthetically made, e.g., those alcohols resulting from the oxo and other processes. The vinyl ethers have the general formula ZOCH:CH

wherein Z is alkyl, alkenyl, aryl, alkoxyalkyl, aryloxyalkyl, alkylaryl and the like containing from 2 to about 40 carbon atoms and preferably from about 8 to about 32 carbon atoms if hard sizing is desired. Representative vinyl ethers include, e.g., the alkyl vinyl ethers such as the oxodecyl, oxo-tridecyl, oxo-hexadecyl, oxo-nonade-cyl, propyl, hexyl, n-decyl, n-dodecyl, n-octadecyl, n-tetracosyl, ntritriacontyl, tetratricontyl, n-hexatriacontyl vinyl ethers, the corresponding alkenyl vinyl ethers, a few examples of which are dodecenyl vinyl ether, heptadecenyl vinyl ether and octadecenyl vinyl ether, as Well as the aryl, aralkyl, and alkaryl, alkoxyaryl, aryloxyaryl, aryloxyalkyl vinyl ethers, e.g., phenyl, benzyl, tolyl, xylyl, dodecylphenyl, octadecylphenyl, dinonylphenyl, methoxyphenyl, ethoxyphenyl, dodecyloxyphenyl, octadecyloxyphenyl, phenoxyhexyl, phenoxyoctyl, phenoxyoctadecyl vinyl ethers, and the like.

For reasons of availability and favorable cost maleic anhydride is preferred as the alpha-beta-unsaturated polybasic carboxylic acid anhydride comonomer in preparing the copolymers which are used in the preparation of the polymeric reaction products. However, other such unsaturated polybasic acid anhydrides which could readily be used to prepare the copolymers and which are included as being useful in this invention are anhydrides such as itaconic acid anhydride, citraconic acid anhydride, and other copolymerizable related homologous unsaturated polybasic carboxylic acid anhydrides.

The diamines or diamine mixtures employed in the formation of the cyclic imides by reaction with the alphaolefin-maleic anhydride copolymer can vary considerably in structure and reactivity. It is only necessary that the diamine and the copolymer are capable of being dissolved in a mutual, inert solvent. However, for the purposes of the present invention, it is preferred to employ diamines of the structure wherein R and R, which may be like or unlike, are hydrogen, alkyl groups containing from 1 to about 22 carbon atoms, aralkyl groups containing from 7 to 10 carbon atoms, hydroxyalkyl groups having from 2 to about 4 carbon atoms, and R" is an alkylene radical containing at least two carbon atoms and generally not greater than about 20 carbon atoms. The preferred amines are alkylenediamines containing from 2 to about 30 carbon atoms. If desired, R" may be phenylene or alkyl substituted phenylene. The diamino compounds employed can be substituted or unsubstituted. When substituents are present in R, R and R", it is only necessary that they are less reactive with the anhydride than is the primary amino group, and that they are not alpha to the nitrogen atoms. Suitable noninterfering substituents include hydroxy, cyano, acetyl, aryl, benzoyl, tert.-amino, ether groups, sulfonyl, arylthio, alkylthio and the like.

It is generally preferred that neither R nor R in the above formula be hydrogen. In other words, it is preferable to employ tertiary amines of the above type with a low degree of steric hindrance in the process of the present invention. The use of a tertiary amine at this point in the synthesis reduces to a minimum any possibility of crosslinkage prior to reaction with the epihalohydrin compound. Reactivity of the amine mixture is enhanced when it contains at least about 30 mol percent of dimethylamino groups. In some instances, a secondary or even a primary amine can be employed to advantage in preparing these polymeric materials. Also, amines of the above type can be partially replaced with various other amines such as amide-forming compounds, such as N-alkyl trimethylene diamines in which the alkyl group is derived from coconut, soya and tallow fatty acids and which are commercially available under the tradename Duomeen, butylamine, octadecylamine, various soluble ammonium salts, and the like.

Although it is preferable to use N,N-dimethylaminoalkylenediamines, and particularly N,N-dimethyl-1,3-propanediamine, numerous other diamines corresponding to the above general formula are suitable in the present process. Representative members of this group of diamines include, for example, N,N-dimethylethylenediamine, N- methylethylenediamine, N-ethylethylenediamine, N-hydroxyethylethylenediamine, N hydroxypropylethylenediamine, N hydroxypropyl-propylenediamine, N-hydroxypropyl-1,3-propanediamine, N-hydroxypropyl-l,6-hexane diamine, N-hydroxypropyl-Z-oxa-1,6-hexanediamine, N-2- aminoethylpiperazine and N-3-aminomethylpyridine.

It is preferred to use mixtures of N,N-dimethylamino-1, 3-propylenediamine and N-hydroxyethylethylenediamine in equivalent ratios of from about 20:80 to :20. An example of a preferred mixture of amines which may be used is a mixture of about 66.5 equivalents of N,N-dimethylaminocthylenediamine and about 28.5 equivalents of N- (2-hydroxyethyl)ethylenediamine for each equivalents of maleic anhydride in an oxo-tridecyl vinyl ether/maleic anhydride copolymer.

In conjunction with tertiary substituted diamines, minor amounts (up to about 20 mol percent) of unsubstituted polyamines may be substituted in order to attain a higher viscosity in the product. Representative polyamines include ethylenediamine, propylenediamine, 1,6-hexanediamine, diethylenetriamine, iminobispropylamine, triethylenetetramine and tetraethylenepentamine.

The amidation-imidation of the maleic anhydride copolymer is generally preceded by mixing with the warm (7075 C.) copolymer-aromatic hydrocarbon (e.g., xylene) solution an appropriate alcohol to open at least some of the anhydride rings and to at least partially esterify the polymer. Thus, the polymers are referred to simply as alpha-olefinmaleic copolymers which term is intended to include the use of maleic anhydride, and acid containing copolymers as well as the esterified copolymers in the reaction solution. Lower alkanols having from 1 to 6 carbons and lower alkyloxyalkanols having up to about 6 or 8 carbons are preferred. Isobutanol, and nbutanol are alcohols of choice. The addition of a small amount of tertiary amine in addition to the alcohol to the copolymer solution appears to promote or catalyze the desired pre-esterification. The chosen diamine or preferably the diamine mixture is then added rapidly to the esterified copolymer xylene-alcohol solution preferably warmed to 73105 C., and then kept warm at from about 110 C. to about 160 C. to replace ester groups and to form first amides and then cyclic imides, while distilling out water, alcohol, and xylene. The 110 C. 160 C. heating step to effect imidation usually is conducted for from 1 to 2 hours. Shorter heating times may be used if high free carboxyl content is not detrimental to the use intended. Longer heating times gives imides having low carboxyl content. Polymeric imide intermediates having about 15% or less carboxyl content are generally most satisfactory for paper treating applications. The resulting polymeric imides are usually obtained as high solid content mixture in the remaining solvent, e.g., as 70-80% solids in xylene mixture. This mixture is preferably diluted to about 30-45% polymer solids content with a lower alkanol such as 2-propanol while cooling to room temperature for reaction with the epihalohydrin.

The polymeric imide-amine formed by the reaction of the diamine with the maleic anhydride-alpha-olefin copoiymer is treated with epihalohydrins to form the corresponding polymeric compound containing epoxypropyl groups. In the interest of convenience and economy, it is generally preferred to use epichlorohydrin in this capacity. However, other epihalohydrins can also be used. The reaction between the epihalohydrin and the polymeric imide-amine can be conveniently carried out at room temperature by adding an appropriate amount of the epihalohydrin to a water diluted solution of the polymeric imide in a conventional solvent such as butanol, ethoxyethanol, butoxyethanol, butoxy carbitol, methanolxylene mixtures, isopropanol-toluene mixtures and the like. Since the reaction is not instantaneous, the amount of the epoxide entering the reaction can be controlled by the reaction time as well as by the amount of the epoxide added to the mixture. Although the reaction progresses slowly in the absence of appreciable water, it is catalyzed and proceeds quite rapidly upon the addition of water. When water is added, the aqueous mixture originally becomes somewhat turbid. This turbidity of the aqueous reaction mixture may usually be dissipated, if desired, by dissolving the reaction product in aqueous mixtures of 2-propanol, e.g., a 2:1 volume waterzZ-propanol mixture. The resulting solution can then be diluted with additional water to any desired concentration. .A portion of the epoxide is hydrolyzed in the aqueous system to the corresponding glycol. Thus, the epoxide content of the polymer product is normally somewhat less than is generally indicated by the amount of reaction between the amine moiety and the epihalohydrin. The degree of hydrolysis of the epihalohydrin or other epoxide can be controlled within limits by controlling alkalinity and by other wellknown methods, thus providing an additional means of tailoring the properties of the product.

Although sufficient epoxide can be made available to react with all of the amine groups in the polymer, it is preferred that the polymeric compounds contain some free amino groups together with the quaternary groups. In general, the numerical ratio of epoxide groups, including hydrolyzed epoxidcs, to cyclic imide groups can vary between about 01:1 and 1:1. It is preferred to maintain this ratio between about 0.15:1 and about 0.511.

The polymeric epoxyalkyl compounds thus obtained have a relatively short shelf or storage life since they are subject to crosslinking and gelation. In order to stabilize them in a convenient, commercially available form they are preferably treated with a hydrohalic acid, either alone or in combination with other mineral acids such as phosphoric, sulfuric and the like. Altemately, tne compounds may be stabilized with a mineral acid composition containing no hydrohalic acids. Such stabilizing compositions neutralize amino groups present, but do not added to the epoxides. When substantially halidefree acid compositions are used for stabilization, some halide ion is present due to the epihalohydrin in the system, and adds to the epoxides. In any event, suificicnt halide ion must be present to effect stabilization of the epihalohydrin groups in the product. This treatment with the hydrohalic acid converts the polymeric epoxyalkyl compounds to the correspondingly more stable haloalkauol compounds which essentially stops further reaction or polymerization. These polymeric alkanols are stable for long periods of time, and thus can be subjected to normal shipping and storage without any danger of crosslinking or consequent gelation.

With the acid stabilized polymeric imideamine/epihalohydrin reaction products derived from alpha-olefin hydrocarbon/maleic anhydride copolymers it is generally desirable to pretreat them with an alkaline material, i.e., a base such as an alkali metal hydroxide to put them in a chemical form most suitable to efficiently size the cellulose pulp or paper. Simiiar acid stabilized products prepared from the alkyl vinyl ether/maleic anhydride copolymers, and generally those from more viscous imides, do not generally require such pretreatment before application to the pulp slurry or paper. This alternative is of great benefit to the paper-maker users of the reaction product in that these products obviate any necessity for expensive machinery to pretreat the chemical size composition before application to the pulp.

Based upon the best information currently available, the active groups (shown in the quaternary salt form) in these polymeric alpha-olefin/maleirnideamine epihalohydrin reaction products are believed to be polymeric epoxyalkyl quaternary ammonium salts containing randomly recurring units of the following structures when the alpha-olefin used is a hydrocarbon alpha-olefin:

wherein R and R can be hydrogen, alkyl groups containing up to 4 carbon atoms, hydroxyalkyl groups having from 2 to about 4 carbon atoms, and arallryl groups containing up to 10 carbon atoms,

A is chloride, bromide, or iodide,

r is a whole number from 2 to 20,

t is a positive whole number up to about 40, and

x and y are numbers greater than 0, the preferred ratio of y to x being at least about 0.9:1.

Since the present polymeric sizes preferably contain free amino groups and can also contain non-epoxy quaternary groups, the following general formula illustrates the type of randomly recurring units that may be present.

corded. The higher number of inches of liquid hydrostatic pressure withstood by the test paper the better the resistance to that liquid.

For example, the water height may rise to only 1 or wherein X denotes the oxygen of an alkyl or alkenyl vinyl ether, a chemical bond, or a -phenylene-carbon atom bridge, and wherein R, R, A, r and t have the above-assigned values,

R' is an allryl or a monoor dihydroxy alkanol group containing 1 to 3 carbon atoms or an aralkyl group containing 7 to 10 carbon atoms, and

x, y, z and s are whole numbers, with s being between and about 75% of the sum of y, z and s; y being equal to at least about of said sum, and the ratio of said sum to x being at least about 1:1.

As pointed out above, this type of material has a propensity to crosslink and to form a gel and this is good in a paper web. But, to prevent premature gelation, as during storage before use, they can be readily converted to the corresponding alcohols, or more precisely the corresponding 1-substituted-Lalkanols, by stabilization with a hydrohalic acid, particularly hydrochloric acid. It is not necessary to convert all of the quaternary ammonium salts to the corresponding alkanols, but it is only required that the stabilized form of the composition contain a preponderant proportion of the alcohols. It is preferred that enough acid be added to reduce the pH to below about 3.0 to insure product stability. The stabilized polymer derivative obtained by the acidification is believed to be a, polymer having randomly recurring units of the following structures when the alpha-olefin of the wherein R, R, A, r, t, x and 1 have the above-assigned values, and Y is chloride, bromide, or iodide with the above indicated 2 and s type groups remaining the same.

The test procedure identified in the tables hereof as modified penescope is a form of hydrostatic pressure test adopted for use on paper samples to determine the relative water-resistance characteristics thereof. It is similar in principle to a test method 18l961 (American Society for Testing and Materials Designation D583-58) adapted for testing the water resistance of any textile fabric which may or may not have been given a waterresistant or water-repellant finish. The method as used for paper, however, differs in that the rate at which the hydrostatic head is increased is 6 inches per minute. The height (in inches) to which water rises in a pressure cylinder at the instant drops appear at five separate points on the upper side of the test paper sample is re- 2 inches before the drops appear when an unsized paper sample is tested. For a hard-sized paper, the water height will reach 2530 inches before the drops appear.

The term ionic precipitating agents is used herein to include as a group the various conventional inorganic and organic chemicals which in aqueous pulp slurry containing the sizing ingredients are sufliciently ionic to attract or pull together the sizing particles and the cellulose pulp particles. Examples of such materials are the inorganic salts such as the aluminum salts such as aluminum sulfate, aluminum chloride, sodium aluminate, and the organic ionic precipitating agents such as the cationic starches, e.g. those containing quarternary ammonium salt groups, and other related papermaking chemicals.

The invention and the manner in which it accomplishes its objects will be more readily understood by reference to the following detailed description of preferred embodiments thereof. In these examples and throughout the application, all proportions are expressed in parts by weight unless otherwise indicated. To show the effectiveness of the sizing method of this invention the more difl'lcultly sized bleached pulps were used to prepare the papers.

EXAMPLE 1 A. Rosin size A fortified tall oil paste rosin size was prepared by neutralizing tall oil rosin to an acid number of about 20 with alkali metal hydroxide as described in U.S. Patent 2,994,635.

For test purposes, quantities of paste size of the above type, weighed to the nearest 0.01 g. were taken to give 3.00 g. of rosin size solids per g. of rosin size aqueous emulsion. Boiling water was added to the weighed paste samples to obtain clear emulsions.

B. Chemical size A synthetic chemical size was prepared by reacting an octadecene-maleic anhydride (octadecenezmaleic anhydride mole ratio of 0.84) copolymer, having specific viscosity as a 4 percent solution in methyl ethyl ketone of 0.085 with N,N-dimethylamino-l,3-propanediamine in butoxyethanol-l followed by reaction thereof with epichlorohydrin to an epichlorohydrin/amine ratio of 33.8, and then with hydrochloric acid to stop further reaction. The reaction product as prepared had a percent solids content of 11.25%. The final viscosity of this resulting reaction product was 0.732.

A bleached Gatineau sulfite pulp was dispersed in water at 2% pulp solids consistency with a Lightnin stirrer in a stainless steel can for 20 minutes and then refined in a Mead refiner to a Canadian Standard Freeness of 500:20 ml.

The refined pulp slurry was sized with rosin by adding at once neutralized fortified rosin size as described above, as a 3% aqueous emulsion to a sufficient portion of the 2% pulp slurry to equal 0.3% or 1.0, by weight, based on the weight of the dry pulp, and stirring the mixture for 15 minutes. After this time the desired amount of alum [Al (SO was added as a 3% solution and the treated pulp slurry was stirred for another 15 minutes.

The synthetic chemical size of the above described type was prepared for application to the pulp as follows:

The amount of the chemical size to give the desired percentage based on the dry fiber present in the pulp was weighed to the nearest 0.01 g. and diluted with water to a little less than 1% concentration. The aqueous solution thus obtained was treated with 0.1 N sodium hydroxide and the pH was brought to 10.5. The mixture was allowed ot stand 15 minutes and then neutralized to pH 7.0 with 0.1 N hydrochloric acid. The resulting solution was then diluted with water to a total volume of about 350450 ml. (about 0.2% concentration).

The rosin sized pulp obtained as described above was treated while stirring with this prepared synthetic chemical size solution. The pulp pH was adjusted to the desired test pH, either 4.5 or 7, and then handsheets were prepared on a Noble and Wood Machine from the sized pulp thus obtained. The water used in the handsheet preparation was demineralized and adjusted to the same pH as the treated pulp. Evaluations were made on sized paper samples on one-day and 7 day aged papers.

The results of the evaluation on the various sets of sized papers are given in Table I.

iii)

12 meric vinyl ether/maleimidechloropropanol product containing 30.8 percent of chlorohydrin, and 86.8% of the theoretical total basic amine present in the maleimide, of which 13.2% of the nitrogen was quaternarized. The product was stabilized against further reaction by treating it with 80 m1. of water and 8.0 g. of cone. hydrochloric acid.

EXAMPLE 3 An oxo-tridecyl vinyl ether-maleimideepichlorohydrin reaction product, prepared as described in Example 2, but obtained by reacting vinyl ether:maleic anhydride in a mole ratio of 111.05 and reacted with the N,N-dimethylamino 1,3 propanediamine:Z-hydroxyethylethylenediamine mixture in a 1.0.0.6 ratio and heated to give a copolymeric vinyl ether:maleirnide viscosity of 0.78 (Ostwald method, supra), and reacted with suflicient epichlorohydrin to give the copolymeric oxo-tridecyl vinylether/maleimide-chlorohydrin reaction product containing 24.2 percent chlorohydrin, and 91.5% of the theoretical total basic nitrogen present in the copolymeric maleimide, of which nitrogen 8.5 percent was quaternarized. The product was stabilized with HCl as in Example 2.

EXAMPLE 4 A copolymeric oxo-tridecyl vinyl ether/maleimideepichlorohydrin reaction product was prepared as described in Example 3, except that sufficient epichlorohydrin was reacted with the copolymeric vinyl ether/ maleimide to give a product containing 33.2% chlorohydrin, and 75.3% of the theoretical total basic amine TAB LE I Sizing Chemicals, Percent In]; Penetration Modified H2O Paper (See) Peuescope Pene- Set N0. (Inches), tration Rosin Alum Crem. 1 day 7 days 7 days (See) ize 1. 0 2 7 0 0 4. 3 1. 0 2 2 7 85 80 2S 6, 000+ 0. 0 0 2 7 0 0 4 0 1. 0 0 0 7 0 0 2 0 1. 0 2 0 7 10 10. 5 (i0 1. 0 0 2 4. 5 0 0 3. 5 0 l. 0 2 2 4. 5 230 230 29 0, 000+ 1. 0 0 0 4. 5 0 0 2 0 1. 0 2 0 4. 5 140 175 17. 5 6,000+

In summary, the data show that the combination sizing treatment of this invention is more effective than sizing with the neutralized fortified rosin size alone and also show that in general, this effectiveness is greater than the sum of the results obtained with the two sizing components.

EXAMPLE 2 A copolymeric vinyl ether/maleirnide size was prepared as follows:

Oxo-tridecyl vinyl ether was copolymerized with maleic anhydride in toluene at 72-73 C. using a vinyl ether: maleic anhydride charge ratio of 0.95:1 and 0.3 mole percent of azo-bis-isobutyronitrile, (AIBN) based on the molar content of maleic anhydride, as an initiator. The specific viscosity (multiplied by 4) of the copolymer thus obtained was 2.51 centipoises (Ostwald method1% of the copolyrner in methyl ethyl ketone times 4). The copolyrner was treated in 2-butoxyethanol-1 solution with a :50 mixture of N,N-dimethylamino-1,3-propanediamine and N (2 hydroxyethyl) ethylenediamine and heated to 130 C. to form the polymeric imide therefrom. A 162.6 g. batch of the copolyrneric vinyl ether/ maleimide (0.05 mole) solution containing 14.4% solids and 18.4 percent 2-butoxyethanol-1 was reacted with excess epichlorohydrin. When the reaction was completed the excess epichlorohydrin was removed with some butoxyethanol-l by distillation to leave a residue a copolypresent in the copolymeric maleimide, of which nitrogen 24.7% was quaternarized. The product was stabilized as in Example 2.

EXAMPLE 5 EXAMPLE 6 A copolymeric oxo-tridecyl vinyl ether/maleimide epichlorohydrin reaction product was prepared as described in Example 5 except that sufiicient epichlorohydrin was used to provide the copolymeric oxo-tridecyl vinyl ether/maleimide epichlorohydrin product with 35.2% chlorohydrin, and 84.9% of the theoretical total basic nitrogen present in the copolymeric Inaleimide, of which nitrogen 15.1% was quaternarized. The product was stabilized with HCl as in Example 2.

13 EXAMPLE 7 Handsheets of sized paper were prepared from bleached Gatineau sulfite pulp having a Canadian Standard Freeness of 498 and a pH of 4.5 according to the procedure described in Example 1. The pulp used was sized with a neutralized fortified rosin size, prepared as described in Example 1 using alum to precipitate the size on the fibers and then with one of the copolymeric maleimideepichlorohydrin reaction products prepared as described in Examples 2 to 6. For comparative examples some pulps were sized only with rosin and alum, and others were sized only with the copolymeric maleimide-epichlorohydrin reaction product. It will be noted from the data given below that the quantity of the copolymeric maleimide-epichlorohydrin reaction product used was, by itself, too low to effect any resistance to lactic acid solution penetration but that combined with the rosin size, the resistance to lactic acid penetration was greatly increased. Table II summarizes the results obtained on seven day evaluations of these sized paper sheets.

TABLE II.7 DAY EVALUATION TABLE III.-ONE (1) DAY EVALUATION Alum, Imide-Halohydrin Percent 0.2% (Ex. N o.)

Ink Penetration (sec) Rosin Size, Percent 0.2% Imide- 20% Lacl lodified 90 Sec.

Rosin Size, Alum, Halohydn'n Ink Pene. tic Acid Penescope Water Percent Percent (Ex. No.) (See) Per(1gsco)pe (Inches) Pickup sec.

EXAMPLE 8 45 These data In Table III establish that the combined ef- Sized handsheets were prepared from bleached southern hardwood kraft pulp having a Canadian Standard Freeness of 504 and :a pH of 4.5 according to the procedure described in Example 1 except that the copolymeric ox tridecyl vinyl ether/maleimide-epichlorohydrin reaction products of Examples 2 to 6 were substitute-d for the copolyineric 1naleimide-epichlorohydrin reaction product of Example 1.

Evaluation of the handsheets after 1 day gave the ink penetration resistance data of Table III.

fectiveness of the rosin size and the copolymeric vinyl ether/maleimideepichlorohydrin size at this level of application is greater than the sum of the two sizes separately.

After seven days additional samples of the same sized papers were tested for ink penetration resistance, lactic acid penetration resistance (penescope), for modified penescope rating and for amount of water picked up in sec. The results are summarized in Table IV.

TABLE IV Rosin 0.2% Imide- 20% Lac- Modified 90 Sec.

Size, Alum, Halohydrin Ink Pene. tic Acid Penescope H2O Pickup Percent Percent (Ex N0.) (sec) Ie(nesc)ope (inches) (mg/g.) sec.

1 The results of Table IV demonstrate that the sizing effectiveness of commercial rosin sizes is greatly increased by use thereof with only small amounts of the copolymeric maleimide-epichlorohydrin reaction products.

16 EXAMPLE 11 Bleached Gatineau sulfite pulp in a 2 percent aqueous slurry was treated with 1 percent by weight of rosin size, prepared as described in Example 1, 2 percent by weight EXAMPLE 9 5 of alum, and then either 0.20 percent, 0.10 percent or 0.05 Handsheets of sized paper were prepared from bleached 5223;? 2 5 ;352: 3 g z l g g i Gatineau sullite pulp having a Canadian Standard Freeness adlusted to 7 g sodium g f i i}; i of 501, in which the pulp was treated with a commercially {related U1 g wareg formpd into er'sheeis ard available partially neutralized but unfortified gum rosin 10 evaluatag a Sizin age/r SW61; 63 S i results size containing 0.5 part of sodium chloride per 100 parts g y as follows. of gum ros1n and alum, and With one of the copolymeric vinyl ether/maleimide-epichlorohydrin reaction products of Examples 2 to 6 at 0.2% concentration, based on the weight of the pulp. The size-treated pulp was adjusted to TABLE v pH 4.5 before the handsheets were prepared therefrom.

P Ink M The seven day evaluation data 1s summarized 1n Table V. meant Pene- Pe gs c ci piz P1363 1 The commercially available neutralized but unfortified gf g g (inches) (mg/E3 rosin size used for this example was a gum rosin neutralized with alkali metal hydroxide to an acid number of {8 8 :8 g8 g 275 251 l6-18 (mg. KOH/gm.) havmg a color no darker than 1.0 0.05 48 17 274 G, an air stabilization factor of 20 percent maximum, 3. 0 21 13 313 solids content based on 2 gm. samples at 120 C.) of 6971%, a viscosity at 45 C. of poises maximum, and a yield point at C. of 0.04 gm./cm. maximum. 25

TABLE V.-SEVEN DAY EVALUATION Rosin 0.2% Imide- 20% Lactic Modified 90 Sec. Size, Alum, Halohydrin Ink Pene. Acid Pcnesco e Water Percent Percent; (Ex. No.) (see) Penescope (inches Pickup ee) ale) 1. 0 2. 0 4s 15.5 295 1. 0 2. 0 2 207 335 33. 25 219 1. 0 2. 0 a 224 287 28.25 237 1. 0 2. 0 4 23s 32. 5 205 1. 0 2. 0 5 232 31. 25 202 1. 0 2.0 6 197 30. 205 1.0 5.0 33 14 304 1. 0 5. 0 2 143 29. 25 220 1. 0 5. 0 3 152 26. 5 239 1.0 5.0 4 159 29.75 235 1. 0 5. 0 5 134 23. 5 237 1.0 5.0 5 26 257 2 101 7 459 3 91 6 589 4 91 8 428 5 79 9.75 491 6 61 10 453 EXAMPLE 10 45 EXAMPLE 12 To a bleached Gatineau sulfite pulp in a 2% pulp solid suspension in water there was added varying amounts of a rosin size, prepared as described in Example 1, ranging from 0.5 to 1.0 percent by weight, 2 percent of alum, and from 0.05 to 0.2 percent of the synthetic chemical size described in Example 6 all of such amounts being based on the dry weight of the fiber. In preparing these test papers, to insure uniformity of mixing, the rosin size was added first, and stirred in the pulp slurry for 15 minutes, then the alum was added, the mixture stirred again for a similar period, and then the synthetic chemical size was added, and the mixture was stirred again. The treated pulp thus obtained was adjusted to pH 7 and then was formed into sheets of paper and tested for degree of sizing after 1 day.

The results in the ink, 20% aqueous lactic acid, modified penescope, and 90 second water pick-up tests were as follows:

Bleached Gatineau sulfite pulp in a 2 percent aqueous slurry was treated with an aqueous rosin size slurry providing 1.0% of rosin size based on the weight of the dry fiber, 0.2 percent of pretreated synthetic chemical size, prepared as described in Example 6, and either sodium aluminate alone (2 percent) or a mixture of 1.5% alum and 0.5 percent sodium aluminate. In other preparations no chemical size was added. In two preparations, the order of addition and mixing of the additives were rosin size, alum (either alone or alum mixed with sodium aluminate) and then chemical size. In another two preparations the order of addition and mixing was chemical size, rosin size, and then alum (either alone or a alumzsodium aluminate mixture). No final adjustment of the pH on the aqueous treated pulps thus obtained was made. The pulps were used to make paper sheets and after '7 days the sheets were evaluated as in the prior examples. The results are given in the following table.

TABLE VI 20 percent Modified 90 Sec. Percent Percent Percent Penetration Lactic Acid Penesco e 1120 Pickup Rosin Alum Ex. 6 by Ink (see) Pe1(1e5cop)e (inches (mg./g.)

sec

Chemical size added to pulp slurry prior to rosin size and alum addition.

2 Only 1 percent rosin size with alum or alum-sodium aluminate were added in these preparations; no chemical size was added.

EXAMPLE 13 A 4.70 g. portion of a 12.4% polymer solids hydrochloric acid acidified solution of a reaction product of epichlorohydrin and a polymeric imide obtained by heating to about 130 C. a 66.5:28.5 molar ratio mixture of N,N-dimethylamino-1,3 propanediamine and N (2 hy droxyethyl)ethylenediamine, respectively, with a xylene/ alcohol solution of a tridecyl vinyl ether/maleic anhydride/ ester copolymer having a vinyl ether/maleic moiety molar ratio of 1:103 and a specific viscosity of 1.89 was added to 200 ml. of hot (about 80 C.) water and stirred until it was dissolved therein. The resulting solution was diluted with water to 2000 ml. For an 0.20% application rate based on the dry fiber used there was used 206 ml. of this two liter solution.

A 1.1 g. portion of a cationic corn starch (Cato 8 of National Starch and Chemical Corp.) was slurried in 100 ml. of cold water, and heated to 9295 C. for 15 minutes with stirring. The resulting solution was diluted fold and 90 ml. portions of the diluted solution (calculated to provide 0.3% of the starch, based On the dry pulp) were used for each test.

A calculated amount of a 3% aqueous rosin size emulsion was added to a 2% slurry of cellulose pulp slurry. For a 1% rosin size application rate 10 ml. of the aqueous emulsified rosin was used. The mixture was stirred minutes, and then treated with ml. of a 3% solution of papermakers alum. The mixture was stirred for another 15 minutes to insure complete dispersion. The pH of the mixture was adjusted to 4.5 with sodium hydroxide and then the mixture was diluted with water to 0.17% solids content. The cationic corn starch solution was added and mixed for 1 minute. Then the diluted polymeric tridecyl vinyl ether/maleimide-epichlorohydrin reaction product solution was added and mixed thoroughly. No pretreatment of the chemical size was used. Then handsheets were formed from the treated pulps and dried on a Noble and Wood machine in the usual manner. The comparative sizing effectiveness of paper obtained from pulp treated as above as compared to paper made from pulp treated with only the rosin size, alum, and cationic starch is summarized in the following table.

TABLE IX Chemical Modified Ink Pene- Modified 90 Sec. H2O Size 1 Penescope 3 tration 4 Penescope Pickup percent (inches) (see) (inches) (mg/g. of

paper) 2 0. 2 25. 75 318 27. 75 208 None 22 155 20. 5 252 amount of the chemical size.

EXAMPLE 14 This example compares and illustrates the obtaining of substantially improved sizing on paper prepared from 18 pulp treated with a small amount of chemical size combined with even smaller amounts of the rosin size with papers prepared from pulps treated with more rosin size than chemical size, and with paper prepared from the chemical size alone.

To an aqueous 2% bleached Gatineau Sulfite pulp slurry there were added, a saponified rosin prepared as described in Example 1, alum, and a composite sample of four batches of the polymeric tridecyl vinyl ether/ maleimide epichlorohydrin product prepared as described in Example 13, which was pretreated with aqueous NaOH to pH 10.5, and then neutralized to below pH 7 before mixing with the pulp.

Ingredient:

Rosin Size, percent 0 0.2 Alum, percent 0 1.0 Chemical Size, percent 0 2 0.4 0.4 Evaluation:

Off Machine: Modified Penescope, (inehes) 25. 75 22. 75 27. 75 One Day:

Ink Resistance (Sec) 105 449 485 Modified Penescope (inches) 26. 25 29. 75 34. 5 Sec. Water Pickup (mg/g.) 238 264 206 EXAMPLE 15 present in an amount equal to 1.0 percent by weight of the weight of the dry fiber in the portion of aqueous pulp treated. The synthetic size was mixed with the rosin size prior to admixture thereof with the pulp in an amount equivalent to 5% or 20% by weight of the rosin size used. Prior to mixing the aqueous rosin size-synthetic size composition to the pulp slurry, the pulp slurry was treated with 2% of alum. The sizing composition was added to the alum treated pulp and the pH was adjusted to 4.5. The thus treated pulp slurry was formed into paper sheets and dried. The sheets were evaluated for the amount of sizing effected after seven days. The results Were as follows:

What is claimed is:

1. A cellulosic web having improved resistance to penetration by liquids comprising a water-laid web of cellulosic fibers having added thereto (1) a rosin size, and (2) a polymeric reaction product of an epihalohydrin and an alpha-olefin/(N-alkylamino)maleimide polymer formed by the reaction of an alpha-olefin/maleic copolymer with a diamine having at least one primary amino group, the alpha-olefin moiety of said copolymer containing from 2 to about 40 carbon atoms the combined amounts of (l) and (2) being sufficient to impart the improved resistance of the resulting cellulose web to penetration by liquids.

2. A sized cellulosic web as described in claim 1 wherein the rosin size (1) is a tall oil rosin size and the polymeric reaction product (2) is the acidified reaction product of epichlorohydrin and an alkyl vinyl ether/ (N- alkylamino)maleirnide polymer formed by the reaction of an alkyl vinyl ether/maleic copolymer with an N,N- dialkylaminoalkylenediamine having from 1 to about 4 carbon atoms in each alkyl group, and from 2 to about 20 carbon atoms in the alkylene group.

3. A sized cellulosic web as described in claim 2 wherein the tall oil rosin size (1) is a substantially completely neutralized tall oil rosin size, and the acidified reaction product (2) is a hydrochloric acid acidified reaction product of epichlorohydrin and a tridecyl vinyl ether/(N,N- dimethylaminopropyl)maleimide polymer.

4. A sized cellulosic web as described in claim 2, wherein the tall oil rosin size, (1) is substantially completely neutralized and the acidified reaction product (2) is a hydrochloric acid acidified reaction product of epichlorohydrin and a decyl vinyl ether/maleimide formed by reacting a decyl vinyl ether/maleic copolymer with a diamine mixture of N,N-dimethylamino-1,3-propanediamine and N-(2-ethylhydroxy)ethylenediamine.

5. A method of preparing a sized, water-laid, cellulosic web, which comprises mixing with an aqueous cellulosic pulp slurry used to prepare said cellulosic web (1) a rosin size, and (2) a polymeric reaction product of an epihalohydrin and an alpha-olefin/N-(alkylamino)maleimide polymer formed by the reaction of an alpha-olefin/maleic copolymer with a diamine having at least one primary amino group, the alpha-olefin moiety of said copolymer containing from 2 to about 40 carbon atoms, and forming the thus treated aqueous cellulosic pulp slurry into a sized cellulosic web.

6. A method as described in claim 5 wherein the mixing step there is mixed with the aqueous cellulosic pulp and said rosin size (1) and the polymeric reaction product (2) an ionic precipitating agent in an amount sufficient to increase the rate of cellulose pulp absorption of (1) and (2).

7. A method as described in claim 6 wherein the rosin size (1) is a tall oil rosin size, and the polymeric reaction product (2) is the acidified reaction product of an alkyl vinyl ether/(N-alkylamino)maleimide polymer formed by the reaction of an alkyl vinyl ether/maleic copolymer with an N,N-dialkylaminoalkylenediamine having from 1 to about 4 carbon atoms in each alkyl group,

2!) and from 2 to about 20 carbon atoms in the alkylene group.

8. A method as described in claim 7 wherein the tall oil rosin size (1) is substantially completely neutralized, and the polymeric reaction product (2) is a hydrochloric acid acidified reaction product of epichlorohydrin and a tridecyl vinyl ether/(N,N-dimethylaminopropyl)maleimide polymer.

9. A method as described in claim 6 wherein the rosin size (1) is a saponified gum rosin size, and the polymeric reaction product (2) is a hydrochloric acid acidified reaction product of epichlorohydrin and a decyl vinyl ether/maleimide formed by reacting a decyl vinyl ether/ maleic copolyrner with a diamine mixture of N,N-dimethylamino-1,3-propanediamine and N-(2-hydroxyeth yl)ethylenediamine.

10. A composition of matter comprising an aqueous dispersion of (1) a rosin size, and (2) a reaction product of an epihalohydrin with an alpha-olefin/ (N-alkylamino)- maleimide polymer formed by reacting an alpha-olefin/ maleic copolymer with a diamine having at least one primary amino group, the alpha-olefin moiety of said copolymer containing from 2 to about 40 carbon atoms, and which reaction product is treated with sufiicient acid to stabilize said product against premature gelation thereof.

11. A composition of matter comprising an aqueous dispersion of (1) a tall oil rosin size, and (2) a hydrochloric acid acidified reaction product of epichlorohydrin and an alkyl vinyl ether/ (N-alklylamino)maleimide polymer formed by reacting an alkyl vinyl ether/maleic copolymer with an N,Ndialkylaminoalkylenediamine having from 1 to about 4 carbon atoms in each alkyl group and from 2 to about 20 carbon atoms in the alkylene group.

References Cited UNITED STATES PATENTS 3,150,112 9/1964 Toy 260-174 WILLIAM H. SHORT, Primary Examiner.

J. NORRIS, Assistant Examiner.