US3899389A - Cellulosic materials internally sized with copolymers of alpha beta-ethylenically unsaturated hydrophobic monomers and ammoniated carboxylic acid comonomers - Google Patents

Abstract

Cellulosic materials such as paper are internally sized by treating fibers of the cellulosic material, e.g., paper pulp, with a copolymer of an Alpha , Beta -ethylenically unsaturated hydrophobic monomer and an ammoniated Alpha , Beta ethylenically unsaturated carboxylic acid and a reaction product of epihalohydrin and ammonia. Internal sizing of the cellulosic material by this method can be carried out under acidic, neutral or basic conditions.

Description

United States Patent Vaughn et al.

[4 1 Aug. 12, 1975 CELLULOSIC MATERIALS INTERNALLY SIZED WITH COPOLYMERS OF ALPHA BETA-ETI-IYLENICALLY UNSATURATED l-IYDROPHOBIC MONOMERS AND AMMONIATED CARBOXYLIC ACID COMONOMERS Inventors: Walter Lee Vaughn, Lake Jackson;

Robert James Beam, Angleton, both of Tex.

The Dow Chemical Company, Midland, Mich.

Filed: Feb. 1, 1974 Appl. No.: 438,913

Assignee:

US. Cl. 162/168; 162/164; 162/169; 162/175; 162/185; 260/17.4 CL; 260/17.4 ST; 260/897 A Int. Cl C08g 45/18 Field of Search 260/17.4 CL, 17.4 ST; l62/164,168,175,l85,169

References Cited UNITED STATES PATENTS 4/1971 Brown et al. 162/158 4/1972 Baggett 162/164 7/1972 Purcell 260/897 OTHER PUBLICATIONS Union Carbide BrochureF42958; Products for Paper; PC4-300 An Alkali Dispersible Ethylene Copolymer, Printed 10/70; pp. l-2, 11-12 and 14.

Primary ExaminerMorris Liebman Assistant ExaminerEdward Woodberry Attorney, Agent, or Firm-Richard G. Waterman; Michael S. Jenkins 2 ABSTRACT 21 Claims, N0 Drawings CELLULOSIC MATERIALS INTERNALLY'SIZED WITH COPOLYMERS OF ALPHA BETA-ETI-IYLENICALLY UNSATURATED I-IYDROPHOBIC MONOMERS AND AMMONIATED CARBOXYLIC ACID COMONOMERS BACKGROUND OF THE INVENTION This invention relates to internal sizing of cellulosic material over the complete range of pH conditions which are normally encountered in the cellulosic manufacturing arts.

Cellulosic materials such as paper and paperboard, are often sized with various materials with the purpose of increasing their resistance to water penetration as well as to penetration by other types of aqueous solutions. These materials are referred to as sizes or sizing agents and they may be introduced during the actual manufacture of the cellulosic material, e.g., paper making operation, wherein the process is known as internal sizing, often called beater sizing, wet end sizing or engine sizing. Surface sizing cellulosic materials by applying sizing agent to fabricated sheet or web is also well known; but is usually considered to be substantially different from internal sizing.

The basis of present internal sizing methods is the intimate coating of the individual fibers of the cellulosic material with a material which is insoluble in most materials and is repellant to water. For example, in manufacture of paper, the substance originally and still most widely used for this purpose is rosin or fatty acid. In order to insure the most intimate contact between the rosin and the pulp fiber, the former is added in either the dissolved state or as a finely dispersed emulsion. It is followed by a precipitating agent, usually aluminum sulfate, known to the paper maker as alum. The alum coagulates the rosin, i.e., throws it out of solution or emulsion as a gelatinous precipitate. Since the rosin or emulsion is first mixed thoroughly with the pulp in the beater, the precipitate has a maximum chance of adhering to and being subsequently retained by the pulp. When the pulp is made into paper, the rosin in contact with the pulp adheres to the pulp as small particles, e.g., particles having diameters of one micron or less. The paper having the small particles of rosin adhered to the fibers exhibits the desired strength and ink and water resistance.

In addition to rosins, various water-repellant or hydrophobic materials have been utilized as internal sizing agents. These include fortified rosin, mixtures or rosins with waxes, wax emulsions, ketene dimer emulsions, fluorocarbons, fatty acid complexes of chromium or aluminum chlorides, long chain thermoplastic copolymers, as well as thermosetting condensation-type resins. Although all of these materials are effective under certain conditions, their use is nonetheless subject to one or more limitations.

For example, in the case of rosin, it is only useful as sizing agent in acidic solutions and therefore cannot be used for the sizing of neutral or alkaline pulps. Rosin is inoperable with the latter since it must ordinarily be used in combination with alum, or an acidic aluminum ion donor which is present for the purpose of precipatating and setting the metal rosinate onto the fibers. The use of alum for this purpose is, however, precluded under neutral or alkaline stock conditions. This is a definite disadvantage in paper making since paper produced from neutral or alkaline pulp has been found to have higher strength, greater stability and superior aging characteristics in comparison with paper prepared from acidic pulp. Also, the internal use of alkaline pigments such as calcium carbonate is precluded. This limitation also applies to most wax emulsions which cannot be used on the alkaline side since they are usually combined with small quantities of alum for the purpose of breaking the emulsions. On the other hand, it may be noted that certain sizing agents will not tolerate acidic conditions. In addition to the above described pI-I limitations, the water resistance or water holdout which is obtainable with many of the heretofore employed sizing agents is often inadequate for many applications which require paper or paperboard displaying an exceptionally high degree of waterresistance. Some sizing agents provide complete water repellancy as opposed to the desired limited amount of water-resistance. Many sizing agents have been found to be incompatible with pigments, fillers or other in gredients which are often added to the paper. A further disadvantage of some sizing agents is that a considerable degree of heat curing is required in order to develop full effectiveness.

For these and other reasons, it would be highly desirable to provide an internal sizing agent which can be effectively employed under acidic, neutral or alkaline conditions and which can be cured to a size having the desired limited water resistance under normal drying conditions used in the early stages of manufacturing paper and other cellulosic materials.

SUMMARY OF THE INVENTION In the present invention, paper and other cellulosic materials are internally sized under pH conditions ranging from moderately acidic through strongly alkaline by an improved internal sizing method. In this improved method for internally sizing the cellulosic material wherein an internal sizing agent is applied to the fibers of the cellulosic material, the improvement comprises the use of a copolymer of an 01,,B-ethylenically unsaturated hydrophobic monomer and an ammoniated a, B-ethylenically unsaturated carboxylic acid as an internal sizing agent and as a retention aid, a reaction product of epihalohydrin and ammonia, or an aliphatic polyamine having at least two amine hydrogens per molecule or mixture of ammonia and polyamine. In another aspect, this invention is an internal sizing composition for a cellulosic material comprising a sizing amount of the aforementioned copolymer and an amount of the aforementioned retentionaid which is effective to retain the copolymer on the cellulosic material. In a further aspect, this invention is a cellulosic material internally sized with the aforementioned composition. The resultant internally sized cellulosic material displays a very desirable degree of water-resistance along with resistance to acidic and alkaline solutions. Of prime importance is the fact that the successful use of the aforementioned copolymers as sizing agents in combination with the aforementioned cationic retention aid is not restricted to acidic pH which thus allows utilization of such sizing agents in the treatment of neutral and alkaline pulp as well as acidic pulp. Furthermore, it is found that only mild drying and curing conditions are needed to develop the full sizing value of such internal sizing agents. I

DETAILED DESCRIPTION OF THE INVENTION For the purposes of this invention, the term cellulosic material is meant to include paper, paper board and other fibrous, sheet-like or molded masses derived from wood, wood pulp, or cotton or other sources of cellulosic fibers. This term also includes sheet-like or molded masses prepared from combination of cellulosic materials and non-cellulosic materials such as polyamides, polyesters, polyacrylic acid resin fibers and mineral fibers such as asbestos, glass and the like.

By the term internal-sizing is meant a method of sizing in which the cellulosic material in raw form, e.g., fibrous stock such as paper pulp, is contacted with the sizing agent under conditions effective to size the cellulosic material, i.e., deposit the sizing agent on the fibers and cure it to full sizingeffectiveness. Accordingly, it is understood that the term internal sizing is generic, and therefore includes such terms as beater-sizing, engine-sizing, internal wet end sizing and the like.

The internal sizing agents suitably employed in the practice of this invention are copolymers of a,,B-ethylenically unsaturated hydrophobic monomer and ammoniated :,[3-ethylenically unsaturated carboxylic acid, i.e., a,B-ethylenically unsaturated carboxylic acid in the ammonium salt form. Generally, such copolymers are water-dispersible, semi-solid or solid materials. Such copolymers have molecular weights which give melt flow viscosities in the range from about 0.2 decigram/minute as measured by ASTM D-l238- 65T(E) to about 50 decigrams/minute as measured using the procedure of ASTM D-l238-65T(B) except that in said procedure the orifice of the extrusion plastometer is 0.020 inch. Preferably, the copolymer has a number average molecular weight, as determined by ebulliometry, in the range from about 1,000 to about 10,000 and a melt flow viscosity in the range from about 0.5 to about 50 decigrams/minute as determined by ASTM Dl238-65T(B) using the plastomer with a 0.020 inch orifice. Preferred copolymers are also filmforming at temperatures used in the sizing operation. By water-dispersible is meant a material which can exist in the form of a stable aqueous colloidal dispersion in the absence of a surface active agent. In addition, the copolymers in the form of aqueous dispersions preferably form films under ambient conditions which films dry to form water-insoluble coatings. By a,B-ethylenically unsaturated hydrophobic monomer is meant any water-immiscible monomer containing a terminal double bond capable of polymerization under normal conditions of addition polymerization to form a waterinsoluble homopolymer having a polyethylenic backbone. By a,B-ethylenically unsaturated carboxylic acid is meant an a,/3-ethylenically unsaturated carboxylic acid which is capable of addition copolymerization through the ethylenically unsaturated group with the a,fi-ethylcnically unsaturated hydrophobic monomer. By ammoniated afi-ethylenically unsaturated carboxylic acid is meant that in the copolymer the carboxylic acid groups are neutralized with ammonia.

Preferably, the internal sizing agent is a normally solid, waterand alkali-insoluble thermoplastic addition copolymer in the form of a fluid aqueous colloidal dispersion. The occurrence of ammoniated acid groups in the polymer should be general throughout the mac romoleeules thereof so that each macromolecule contains a minimum number of active salt groups sufficient to render the polymer water-dispersible as defined hereinbefore. The maximum number of ammoniated acid groups which may be present in the macromolecules is fixed by the requirement that the molecule be substantially water-insoluble. Generally speaking, such copolymers contain from about 6 to about 40 weight percent of ammoniated acid comonomer, with preferred copolymers containing from about 10 to about 20 weight percent of ammoniated acid comonomer and especially preferred copolymers containing from about 15 to about 18 weight percent.

Exemplary preferred copolymers are the random copolymer products of copolymerization of mixtures of one or more polymerizable ethylenically unsaturated carboxylic acids having 3 to 8 carbon atoms inclusive of anhydrides and alkyl half esters of ethylenically unsaturated acids such as acrylic acid, methacrylic acid, maleic acid and anhydride, itaconic acid, fumaric acid, crotonic acid and citraconic acid and anhydride, methyl hydrogen maleate, ethyl hydrogen maleate, and one or more afi-ethylenically unsaturated hydrocarbon monomers such as the aliphatic a-olefin monomers, e.g, ethylene, propylene, butene-l and isobutene; conjugated dienes, e.g., butadiene and isoprene; and monovinylidene aromatic carbocyclic monomers, e.g., styrene, a-methylstyrene, toluene, and t-butylstyrene. In addition, other ethylenically unsaturated hydrophobic monomers which are not entirely hydrocarbon are copolymerized with the aforementioned acid comonomers. Examples of such suitable monomers which are not entirely hydrocarbon include esters of a,B-ethylenically unsaturated carboxylic acids such as ethyl acrylate, methyl methacrylate, ethyl methacrylate, methyl acrylate, isobutyl acrylate, and methyl fumarate; unsaturated esters of non-polymerizable carboxylic acids such as vinyl acetate, vinyl propionate, and vinyl benzoate; vinyl halides such as vinyl and vinylidene chloride; vinyl ethers; a,B-ethylenically unsaturated amides and nitriles such as acrylamide, acrylonitrile, methacrylonitrile and fumaronitrile. It is understood that the aforementioned suitable hydrophobic monomers may be copolymerized with preferred hydrocarbon monomer and the acid comonomer in proportions such that a waterand alkali-insoluble polymer is provided. Preferred copolymers include copolymers from about to about weight percent of ethylene, from about 10 to about 20 weight percent of one or more ammoniated ethylenically unsaturated acids such as acrylic acid and methacrylic acid and from 0 to about 20 weight percent of suitable ethylenically unsaturated hydrophobic monomer as described hereinbefore such as acrylonitrile, ethyl acrylate and vinyl acetate.

Other copolymers which are suitable are made from preformed, non-acid polymers by subsequent chemical reactions carried out thereon. For example, the carboxylic acid group may be supplied by grafting a monomer such as acrylic acid or maleic acid onto a polymer substrate such as polyethylene. Additionally, copolymers containing carboxylic anhydride, ester, amide, acylhalide and nitrile groups can be hydrolyzed to carboxylic acid groups which can then be neutralized to form the ammoniated carboxylic acid.

It is further understood that the a,B-ethylenically unsaturated carboxylic acid in ammonium salt form may be copolymerized with the hydrophobic monomer in order to prepare a suitable copolymer.

Specified procedures and means for making the polymers are known to the art as exemplified by US. Pat. No. 3,520,861 to Thomson et al. and US. Pat. No. 3,426,363 to Helin. Preferred low molecular weight copolymers are prepared according to methods disclosed in the foregoing references except that a telogen such as propylene is employed in the reaction mixture. In instances wherein the acid copolymer is obtained in mass form, the copolymer may be converted to aqueous colloidal dispersion in accordance with the methods of Us. Pat. No. 3,389,109 to Harmon et al. which is subsequently concentrated and ammoniated by the method described in US. Pat. No. 3,644,258 to Moore et al. Generally methods of producing the aqueous colloidal dispersion of a copolymer which require the use of little or no emulsifier or other surface active agents are preferred. Preferably, the aqueous colloidal dispersion of copolymer has a polymer solids content from about 5 to about 60 weight percent and suffieient stabilizing ammonia to give the dispersion a pH of at least about 7.5. High solids dispersions are suitably prepared from lower solids dispersions by the method disclosed in the aforementioned patent to Moore et al.

In order to obtain a degree of sizing which is useful in manufacture of sized paper (including highly sized paper), it is necessary to utilize the copolymer sizing agent of the present invention in conjunction with a reaction product of epihalohydrin and ammonia, or an aliphatic polyamine having at least two amine hydrogens per molecule or a mixture of the polyamine and ammonia, hereinafter collectively referred to as epihalohydrin/amine reaction product. These epihalohydrin/amine reaction products are useful as co-additives which enhance the retention of the copolymer sizing agent and which bring the copolymer sizing agent in closer proximity to the fibers of the cellulosic materials during the sizing operation. Suitable epihalohydrin/amine reaction products are water dispersible, preferably Water-soluble. Generally such water dispersible reaction products have molecular weights in the range from about 1000 to about 80,000. Preferred reaction products comprise from about 0.9 to about 2.]. especially from about 1.5 to about 1.7, mole of epihalohydrin per mole of amine, i.e., ammonia, polyamine or mixture thereof. Generally, such preferred reaction products have one or more molecular weight peaks as determined by gel permeation chromatography and such peaks normally occur in the range from about 2,000 to about 70,000. Especially preferred reaction products are those exhibiting at least one peak in the molecular weight range from about 40,000 to about 70.000 Such reaction products, including their method of preparation, are further described in US. 3,655,506 to Baggett which is hereby incorporated by reference in its entirety.

In the internal sizing of paper and other cellulosic materials using the above-described copolymers as internal sizing agents, a number of variations and tech niques may be employed. It is critical however, that all of the techniques employed achieve uniform dispersal of the sizing agent throughout the cellulosic fiber during internal sizing. Uniform dispersal may be obtained by adding the ammoniated copolymer sizing agent in a fuller dispersed form such as an aqueous colloidal dispersion.

in order to achieve maximum distribution of the copolymer sizing agent on the fiber stock and to avoid tion product to the fiber stock, care must be taken to avoid contact of the ammoniated copolymer and the reaction product prior to contacting the fiber stock.

The actual addition to the cellulosic material fiber of either the reaction product or the sizing agent may take place at any point in the cellulosic material manufacturing process prior to the ultimate conversion of wetfibrous material into web, sheet or molded article. Thus, for example, in paper manufacture, the sizing agent may be added to the pulp while the latter is in the head box, beater, hydropulper or stock chest.

In order to obtain good internal sizing, it is desirable that the ammoniated copolymer sizing agents be uniformly dispersed throughout the fiber in as small a particle size as is possible to obtain. One method for providing such uniform dispersions is to disperse the sizing agent in aqueous media prior to its addition to stock using, for example, a method as described hereinbefore. While it is generally desirable to use the ammoniated copolymer sizing agent in aqueous colloidal dispersion which is free of emulsifiers and surface active agents, such agents can be suitably employed in the practice of the invention provided that such agents are fugitive during sizing or otherwise do not impair the effectiveness of the copolymer sizing agent.

The sizing agents of this invention are most successfully utilized for the sizing of paper prepared from all types of both cellulosic and combination of cellulosic with non-cellulosic fibers. The cellulosic fibers which may most advantageously be used include the bleached and unbleached sulfate (kraft), bleached and unbleached sulfite, bleached and unbleached soda, neutral sulfite, semi-chemical, chemi-ground wood, ground wood and any combination of these fibers. These designations refer to wood pulp fibers which have been prepared by means of a variety of processes which are known in the pulp and paper industries.

It is understood that all types of additives such as pigments, fillers, stabilizers, retention aids, wet strength additives and dry strength additives, additional sizing agents, and the like may be employed in combination with the copolymer sizing agents of the present invention. Such additaments include kaolin clay, talc, titanium dioxide, calcium carbonate, diatomaceous earth, plastic pigments, aluminum trihydrate, and precipitated silica.

The ammoniated copolymer sizing agents are suitably employed in amounts effective to achieve the purposes of the sizing such as water-resistance, i.e., an amount effective to size the cellulosic material. Generally, amounts ranging from about 0.03 to about 20 weight percent based on dry weight of the cellulosic material in the finished sheet or article are suitable, with preferred amounts being in the range from about 0.05 to about 2 weight percent and especially preferred amounts being in the range from about 0.2 to about I weight percent. It is understood that within this numerical range, the precise amount which is used will depend for the most part on the type of cellulosic material which is being employed, the specific operating conditions, as well as the particular end use for which the cellulosic material is destined. For example, paper which will require good water-resistance or ink holdout will necessitate the use of a higher concentration or sizing agent than a paper having characteristics which necessitate the use of only small amounts of sizing. Accordingly, any amount which is suitable to effect the desired end result of the sizing is suitable for the purpose of this invention.

These same factors also apply in relation to the amount of epihalohydrin/amine reaction product which is used as a retention aid in conjunction with ammoniated copolymer sizing agent. Thus, the skilled artisan will be able to use the reaction product and the sizing agent in any concentrations which is found to be applicable to the specific operating conditions of internally sizing cellulosic material as defined hereinbefore. However, as a general rule, the epihalohydrin/amine reaction product is usually employed in amount in the range from about 0.5 to about weight parts per 1 weight part of copolymer sizing agent, preferably from about 1.5 to about 3 weight parts of the reaction product per 1 weight part of copolymer sizing agent.

tained at 16-20C.. 925 g. 10 g. moles) of epichlorohydrin is added over a period of 4 hours. At the end of the addition, the reaction mixture is stirred for another 16 hours at the same temperature, then 330 g. of water is added and the mixture is heated to 100C. and cooled to room temperature over a 2-hour period. A mixture of 200 parts by weight of this prepolymer resin with 100 parts of epichlorohydrin and 200 parts of water is stirred at 9598C. for 2 hours and cooled to room temperature. The aqueous dispersion of copolymer and reaction product solution are added separately to 236 parts of a 0.33 percent solids aqueous slurry of bleached kraft pulp slurry having a pH of 7.8 which is adjusted to pH 4.5 by adding H Handsheets are formed and dried in accordance with TAPPI T-205m- 53. Surface wettability by water (angle of contact) and ink penetration of the handsheets is determined and recorded in Table 1.

As an additional illustration of this embodiment, a sizing composition containing different amounts of the aqueous dispersion of the copolymer and the reaction product is used for internal sizing of the aforementioned pulp. In the foregoing manner, the treated pulp is converted to handsheets and tested for surface wettability and ink penetration. The results are also recorded in Table 1.

TABLE 1 ('opolymer Reaction Product lnk Penetration. Sample Concentration Concentration Reflectance at No. Ih/ton l Type lb/ton l 120 sec. (2) Contact Angle (3). precured 1 o NH,,/EP(H* 15 93 103 2 4 NH /EPCH" 15 70 105 Reaction product ofepichloroh drin/ammonia in the mole ratio of 1.7:1. said reaction product having molecular weight peaks at 5000 and 50.000 as measured by gel permeation chromatography l Measured in dr weight as pounds of specified additive per (2) A photometric determination of black ink penetration lhrough ol'thc paper opposite to which a pool ofthe hlack ink is applied. The

has a 100'; reflectance.

(3) Surface wettability l\ \\'atcr ((ontaci Angle) he be construed as limiting its scope. In these examples, all 4 parts and percentages are by weight unless otherwise noted.

EXAMPLE 1 A 500-g portion of ethylene/acrylic acid (87.3/12.7) copolymer having a molecular weight peak of 6950 as determined by gel permeation chromatography and a melt flow viscosity [ASTM Dl238-65T(B) using a plastometer having a 0.020 inch orifice] of 2 decigrams/minute is added to 240 ml of aqueous ammonia (28 percent NH in a 4 liter kettle containing 2.94 liters of water. The foregoing ingredients are stirred for 8 hours at 100C, and the resulting dispersion is allowed to cool to room temperature. The dispersion is passed through gauze to remove flocculated material. The resulting filtrate is an aqueous dispersion containing 13.6 percent ethylene/ammonium acrylate copolymer solids and having pH of about 8.

A 5-1iter reaction flask equipped with reflux condenser. stirrer, thermometer. and feeding funnel is charged with 431 g. (7 g. moles) of 28-30 percent aqueous ammonia and partially immersed in a cooling bath. With the reaction mixture temperature mainton of pulp.

white or light-colored paper h measuring light reflectance on the side paper tested prior to inking. using a black background of0/ reflectance l'orc curing as determined by TAPPl-458m-4N.

EXAMPLE 2 A 7.3-lb. portion of ethylene/acrylic acid (86/14) copolymer having a melt flow viscosity (ASTM D1238- T(B) with a 0.020 inch orifice) of 2 decig/min. (number average molecular weight of 4,450) is added to 7.5 gallons of water and 0.617 gallons of aqueous ammonia (28 percent NH in a 10 gallon stirred kettle. The kettle is heated and stirred for 3 hours at C and 45 psi. The product is drained and filtered through a 100 mesh stainless steel screen. A good amber colored dispersion having 10 percent copolymer solids is obtained.

A 4-part portion of the epichlorohydrin/ammonia reaction product as used in Example 1 is diluted with 27 parts of water. A 2.9-part portion of the foregoing copolymer dispersion is diluted with 4.8 parts of water. The two dilutions are added separately to a bleached kraft pulp slurry. The mixture is adjusted to a pH of 3.5 with sulfuric acid. The pulp slurry is formed into a handsheet and tested for ink penetration and water contact angle. The foregoing procedure is repeated using pulp slurries adjusted to pH values of 4.8, 6.1, 7.1, 7.9, 9.1, and 10.2. The results of the foregoing tests which are recorded in Table 11 show the copolymer sizing agent to be effective over a wide range of pH.

TABLE ll Additive Concentration l 1 lbs/ton Ethylene/Ammoniatcd I lnk Penetration. Sample Acrylic Acid Ammonia/Epichlorohydrin /r Reflectance at Contact Angle.

No. Copolymer Reaction Product 120 sec. (2) precured (3) pH (4) 1 ll) 15 9X 1 15 3.5 2 1U 15 9X 120 4.8 3 ll) 15 99 117 6.] 4 1t) 15 99 1 18 7.1 5 ll) 1()() 122 7.9 6 ll) 15 95 120 9.1 7 ll) 15 )8 118 10.2

(I Same as in Table I.

(2) Same as in Table l.

(3) Same as in Table l. (4) pH of pulp slurry before processing into handsheets.

EXAMPLE 3 EXAMPLE 4 A -g. portion of ethylene/acrylic acid (89/11) copolymer having a melt flow viscosity [ASTM D-l 238- T(B) with a 0.20 inch orifice] of 43 decig./min. (number average molecular weight of 4,075) is added to 27 g. of aqueous ammonia (28 percent of NH;;) and 200 g. of water in a 0.5 liter stainless steel bomb reactor. The bomb is sealed and the reaction mixture is shaken for 3 hours at C. The resulting dispersion contains 15 percent copolymer solids A 0.18-part portion of epichlorohydrin/ammonia reaction product as used in Example 1 is diluted with 6 parts of water. The resulting solution is added to a bleached kraft pulp slurry in the proportion set forth in Table 111 and is stirred for one minute. A 0.19-part portion of the foregoing ethylene copolymer dispersion is diluted with 7.7 parts of water and is then added to the pulp slurry as an internal size in the proportion specified in Table 111. The pH of the resulting pulp slurry is adjusted to 4.5 with sulfuric acid. The pulp is formed into a handsheet and is tested for ink penetration and water contact angle. The results are listed in Table lll.

TABLE Ill Following the procedure of Example 1, an aqueous dispersion (11 percent copolymer solids) of ammoniated ethylene/acrylic acid (86/14) copolymer having a number average molecular weight of 4,500 is prepared.

An aqueous solution of a retention aid as specified in Table IV is added in proportions specified in Table IV to a bleached kraft pulp slurry (0.3 percent solids in water) while stirring. The ammoniated copolymer dispersion is then added to the stirred pulp slurry in the amount indicated in Table IV. The pulp slurry is converted to handsheets and dried in accordance with TAPPl T-205m-53. Surface wettability by water (angle of contact) and ink penetration of the dried handsheets are then determined. The results are recorded in Table For the purpose of comparison, the foregoing procedure is followed except that a cationic starch is employed as a retention aid. The resultant handsheets are likewise tested for surface wettability and ink penetration. These results are also recorded in Table IV.

Additive Concentration 1 lhs/ton Ammimia/Epichlorohydrin lnk Penetration. "/1 Reflectance at Contact Angle.

Sample Ethylene Copolymer Reaction Product 121) sec. (2) precured (3) (1 P13) Same as in Table 1.

TABLE IV Size Retention Aid lnk Sample Concentration Concentration Beater Contact Penetration. No. Type lb/ton 1 Type lb/ton 1 pH Angle(3) (2). sec.

*Not an example of the invention. (a)

of BUJIUU.

Ammoniated ethylene/acrylic acid (so/l4) copolymer having a number average molecular weight of Ammoniated ethylene/acrylic acid (NUS/19.51 copolymer having a number average molecular weight Ammoniated ethylene/acrylic acid (NU/2U) copolymer having a melt flow viscosity {ASTM DJZ3s-(5 Tl 1'5 1] of 251) dccig/min which approximately corresponds to a number average molecular weight of Reaction product of epichlonihydrin/ammonia in the mole ratio of 1.61:1. said reaction product having molecular weight peaks at 2500 and 65.000 as measured by gel permeation chromatography.

Potato starch hearing quaternary amine groups as follows:

('H. .C-CH l\"((HM. and manufactured by A. l-l. Stalcy Manufacturing.

H l l Same as in Table l. (2)

(3) Same as in Table 1.

Time in seconds taken for paper to have an 811% reflectance using test method (2) in Table l.

EXAMPLE 5 9. The improvement according to claim 7 wherein the carboxylic acid is methacrylic acid. A SO-pound portion of ethylene/acrylic acid (85/15) 10. The improvement according to claim 7 wherein copolymer having a melt flow viscosity of Sdeci g/min, the copolymer is film-forming under the conditions of (ASTM D-l 238-65T(E) is added to 75 pounds of 5 internal i aqueous ammonia (28 percent NH3) and 75 pounds of 11. The improvement of claim 10 wherein the cowater in a 25-gallon stirred kettle. The kettle is heated Polymer has a number average molecular We'ght peak at 140C for five hours. The excess ammonia is stripped m the range from about 1,000 to about IOOOO and at 85C and then the product is drained from the kettle. tains from .about 10 to about weight Percent of afi-ethylemcally unsaturated carboxylic acid.

l The resulting dispersion contains 24 percent copo y l0 12 The Improvement accordmg to Glam 1 whcrem mer sohds' the cellulosic material is internally sized under condi- A fLO-part portion of an epichlorohydrin/ammonia tions of pH of at least a prPduct used m Example I (25 percent 13. An internal sizing composition for a cellulosic solids) is diluted with 27 parts of water. A O.l2-part material Comprising a Sizing amount of a watch POrtion of the foregoing ethylene copolymer dispersion dispersible, waterand alkali-insoluble copolymer of an is parts Of water. The tWO dilutions are a fl-ethylenically unsaturated hydrophobic monomer added to a bleached kraft pulp slurry in the proportions d an ammoniated g h l i ll unsaturated set forth in Table V. The resulting slurry is adjusted to boxylic acid, said copolymer containing from about 6 a pH of 4.5 with sulfuric acid and formed into a handto about 40 weight percent of the ammoniated carboxsheet. The handsheet is tested for ink penetration and 20 ylic acid and a water dispersible reaction product of water contact angle and the results are recorded in epihalohydrin and ammonia, or aliphatic polyamine Table V. having at least two amine hydrogens per molecule or TABLE V Additive Concentration l lbs/ton lnk Penetration- Ammonia/Epichlorohydrin "/1 Reflectance at Contact An le.

Sample Ethylene Copolymer Reaction Product 120 sec. (2) precured l in l5 89 92 (l)( 3) Same as in Table 1.

mixture of ammonia and the polyamine in an amount effective to retain the copolymer on the cellulosic material.

14. The composition according to claim 13 wherein the reaction product has at least one molecular weight peak as determined by gel permeation chromatography What is claimed is:

1. In a method for internal sizing ofa cellulosic material wherein an internal sizing agent and a retention aid are applied to the fibers of the cellulosic material, the improvement wherein the internal sizing agent is a water-dispersible, waterand alkali-insoluble copolymer of an afi-ethylenically unsaturated hydrophobic m the range from #2 9 to about 3 monomer and an ammoniated a,B-ethylenically unsat- The of claim wherem i rem;-

40 tion product is water soluble and the mole ratio of epiuiated arboxyliir acid and the retimtion is a i halohydrin to amine is from about 0.9 to about 2.1 dispersible reaction product of epihalohydrin and am mole of epihalohydrin to 1 mole of amine.

f or an ahphanc polyamme hav mg at least two 16. The composition according to claim 13 wherein ainme hydfogePs per moiecule or a mlxture of ammothe hydrophobic monomer is ethylene and the carboxnia and aliphatic polyamine. ylic acid is acrylic acid.

2. The improvement of claim 1 wherein the reaction The Composition of claim 13 wherein the hydro product has at least one molecular weight peak as dephobic monomer f the copolymer is ethy]ene termined y gel Permeation Chromatography in the 18. A cellulosic material internally sized with waterrange from about 2,000 to about 70,000. dispersible, waterand alkali-insoluble copolymer of an 3. The improvement according to claim 1 wherein 5O a,,8-ethylenically unsaturated hydrophobic monomer the reaction product is water soluble and the mole ratio and an ammoniated a,,8 ethylenically unsaturated carof epihalohydrin to amine i from ab t 9 to about boxylic acid, and a water-dispersible reaction product 2.1 mole of e ihalohydrin t 1 l f i of epihalohydrin and ammonia, aliphatic polyamine 4. The improvement according to claim 1 wherein having at least two amine hydrogens per molecule or the cellulosic material is pulp. mixture thereof.

5. The improvement according to laim 1 wherei 19. The cellulosic material of claim 18 wherein the the hydrophobic monomer is an a,B-ethylenically uncopolymer contains from about l0 to about 20 weight saturated hydrocarbon. percent of the carboxylic acid.

6. The improvement according to claim 5 wherein 20. The cellulosic material of claim 18 wherein the the hydrocarbon is an aliphatic a-monoolefin having 2 cellulosic material is paper. to l4 carbon atoms. 21. The cellulosic material of claim 18 wherein the 7. The improvement according to claim 6 wherein reaction product is water-soluble and the mole ratio of the aliphatic a-monoolefin is ethylene. epihalohydrin to amine is from about 0.9 to about 2.1

8. The improvement according to claim 7 wherein mole of epihalohydrin to one mole of amine.

the carboxylic acid is acrylic acid.

Claims (21)

1. IN A METHOD FOR INTERNAL SIZING OF A CELLULOSIC MATERIAL WHEREIN AN INTERNAL SIZING AGENT AND A RETENTION AID ARE APPLIED TO THE FIBERS OF THE CELLULOSIC MATERIAL, THE IMPROVEMENT WHEREIN THE INTERNAL SIZING AGENT IS A WATER-DISPERSIBLE, WATERAND ALKALI-INSOLUBLE COPLYMER OF AN A,B-ETHLENICALLY UNSATURATED HYDROPHOBIC MONOMER AND AN AMMONIATED A,BETHYLENICALLY UNSATURED CARBOXYLIC ACID AND THE RETENSION AID IS A WATER DISPERSIBLE REACTION PRODUCT OF EPHALOHYDRIN AND AMMONIA, OR AN ALIPHATIC POLYMINE HAVING AT LEAST TWO AMINE HYDROGENS PER MOLECULE OR A MIXTURE OF AMMONIA AND ALIPHATIC POLYAMINE.

2. The improvement of claim 1 wherein the reaction product has at least one molecular weight peak as determined by gel permeation chromatography in the range from about 2,000 to about 70,000.

3. The improvement according to claim 1 wherein the reaction product is water soluble and the mole ratio of epihalohydrin to amine is from about 0.9 to about 2.1 mole of epihalohydrin to 1 mole of amine.

4. The improvement according to claim 1 wherein the cellulosic material is pulp.

5. The improvement according to claim 1 wherein the hydrophobic monomer is an Alpha , Beta -ethylenically unsaturated hydrocarbon.

6. The improvement according to claim 5 wherein the hydrocarbon is an aliphatic Alpha -monoolefin having 2 to 14 carbon atoms.

7. The improvement according to claim 6 wherein the aliphatic Alpha -monoolefin is ethylene.

8. The improvement according to claim 7 wherein the carboxylic acid is acrylic acid.

9. The improvement according to claim 7 wherein the carboxylic acid is methacrylic acid.

10. The improvement according to claim 7 wherein the copolymer is film-forming under the conditions of internal sizing.

11. The improvement of claim 10 wherein the copolymer has a number average molecular weight peak in the range from about 1, 000 to about 10,000 and contains from about 10 to about 20 weight percent of Alpha , Beta -ethylenically unsaturated carboxylic acid.

12. The improvement according to claim 1 wherein the cellulosic material is internally sized under conditions of pH of at least 7.

13. An internal sizing composition for a cellulosic material comprising a sizing amount of a water-dispersible, water- and alkali-insoluble copolymer of an Alpha , Beta -ethylenically unsaturated hydrophobic monomer and an ammoniated Alpha , Beta -ethylenically unsaturated carboxylic acid, said copolymer containing from about 6 to about 40 weight percent of the ammoniated carboxylic acid and a water dispersible reaction product of epihalohydrin and ammonia, or aliphatic polyamine having at least two amine hydrogens per molecule or mixture of ammonia and the polyamine in an amount effective to retain the copolymer on the cellulosic material.

14. The composition according to claim 13 wherein the reaction product has at least one molecular weight peak as determined by gel permeation chromatography in the range from about 2,000 to about 70,000.

15. The composition of claim 14 wherein the reaction product is water soluble and the mole ratio of epihalohydrin to amine is from about 0.9 to about 2.1 mole of epihalohydrin to 1 mole of amine.

16. The composition according to claim 13 wherein the hydrophobic monomer is ethylene and the carboxylic acid is acrylic acid.

17. The composition of claim 13 wherein the hydrophobic monomer of the copolymer is ethylene.

18. A cellulosic material internally sized with water-dispersible, water- and alkali-insoluble copolymer of an Alpha , Beta -ethylenically unsaturated hydrophobic monomer and an ammoniated Alpha , Beta -ethylenically unsaturated carboxylic acid, and a water-dispersible reaction product of epihalohydrin and ammonia, aliphatic polyamine having at least two amine hydrogens per molecule or mixture thereof.

19. The cellulosic material of claim 18 wherein the copolymer contains from about 10 to about 20 weight percent of the carboxylic acid.

20. The cellulosic material of claim 18 wherein the cellulosic material is paper.

21. The cellulosic material of claim 18 wherein the reaction product is water-soluble and the mole ratio of epihalohydrin to amine is from about 0.9 to about 2.1 mole of epihalohydrin to one mole of amine.