CS264115B2 - Emulsion size on the base of alkenylsuccinic acid anhydride - Google Patents

Abstract

Cationically charged water soluble vinyl addition polym- mers provide improved emulsification of alkenyl succinic anhydride sizing agents. Sized paper products prepared from alkenyl succinic anhydride emulsions made with the polymers have superior ink holdout and strenghth.

Description

The invention also relates to an alkenylsuccinic anhydride (ASA) emulsion type sizing agent suitable for sizing cellulosic materials, such as paper products.

Alkenyl succinic anhydrides useful in sizing cellulosic materials have achieved considerable commercial success. These compounds were first fully described in U.S. Patent No. 3,102,064. This patent discloses a class of chemical compounds whose structure can be described by the general formula:

1 «

where

R is dimethylene or trimothylene and is a hydrophobic group having more than 5 carbon atoms selected from the group consisting of alkyl, alkenyl, aralkyl and aralkenyl groups.

In the description of the use of ASA-based sizing agents disclosed in the above-cited US patent, the Applicant shows that for effective use, the sizing agents have to be used in conjunction with a substance having either a cationic nature or capable of ionizing or dissociating in such a way that one or more cations or other positively charged groups. Cationic agents include alum, aluminum chloride, long chain aliphatic amines, sodium aluminate, polyacrylamide, chromium sulfate, animal glue, cationic thermosetting resins, and polyamide polymers ¹¹ . Preferred cationic agents here are, in particular, agents made up of various cationic starch derivatives, such as primary, secondary, tertiary and quaternary starch amine derivatives and other nitrogen-substituted starch cationic derivatives and cationic sulfonium and phosphonium starch derivatives. Such derivatives can be prepared from all types of starch, such as corn, tapioca, potato starch, etc., as indicated by the applicant.

The growing industrial use of sizing of the type described above is complicated by the serious problems that persist in their application to the pulp or pulp prior to its foliation or other suitable form. Part of this problem is that ASA-based sizing agents are not water-soluble and therefore need to be uniformly suspended in the pulp so that the sizing can be properly contacted in the cellulosic fibers and applied in the final product as desired.

Although the cationic agents disclosed in U.S. Patent No. 3,103,061 have been successful, there is an attempt in the paper industry to produce more efficient cationic agents for ASA-based sizing agents. Furthermore, such cationic agents should preferably aid in retention of the sizing agent on the fiber and should, if desired, increase the wet and / or dry strength of the resulting sheet materials.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a group of additives for emulsifying or dispersing ASA-based sizing agents in pulp and for retention of these sizing agents on the fiber.

SUMMARY OF THE INVENTION The present invention provides an emulsion type alkenylsuccinic anhydride-type sizing agent useful in the manufacture of sized paper products comprising an emulsion containing 50-99.9% by weight water, 0.01-40% by weight alkenylsuccinic anhydride and 0.0001-10.0% by weight of a cationic agent, characterized in that it contains as a cationic agent a water-soluble cationic vinyl addition polymer having a molecular weight in the range of 10,000 to 1,000,000;

SUMMARY OF THE INVENTION Briefly defined above is the use of cationic, water-soluble vinyl addition polymers with molecular weights above 10,000 and below 1,000,000 as additives and emulsifiers for ASA-based sizing agents. These cationic vinyl addition polymers serve as useful emulsifiers for ASA-based sizing agents and additionally increase sizing retention in the cellulosic sheet.

As the ASA-based sizing agents, the sizing agents disclosed in U.S. Patent Nos. 3,102,061, 4,040,900, 3,968,005 and 3,821,069 can be used in the context of the invention.

The structure of the ASA-based sizing agents which can be used in the process of the invention is represented by the general formula

About where

R represents a dimethylene or trimethylene group; represents a hydrophobic group containing more than 5 carbon atoms selected from the group consisting of alkyl, alkenyl, aralkyl and aralkenyl groups.

In a particularly preferred embodiment of the present invention and in the manufacture of ASA-based sizing agents, it also uses surfactants. The surfactant used may be anionic, nonionic or cationic in nature. The surfactants used are generally water-soluble and have a hydrophilic-lipophilic balance (HLB) value in the range of about 8 to about 30 or higher, and preferably in the range of about 8 to 15. When preparing an ASA-based sizing agent, the surfactant is usually a surfactant. The ASA-based sizing agent used in the process of the invention will therefore preferably contain 75 to 99.5 parts by weight of ASA, preferably 90 to 99 parts by weight of ASA together with 0.5 to 25 parts, in a preferred embodiment. , preferably 0.75 to 10 parts, and most preferably 1.0 to 5 parts by weight of surfactant.

Surfactants are preferably added to the ASA prior to emulsification in an aqueous medium. The surfactant may also be added to the aqueous environment prior to the addition of the ASA,

Surfactants useful in the process of the invention are described in more detail in U.S. Patent No. 4,040,900, cited above. The relevant part of this US patent starts at row 54 of column 4 and continues up to row 46 of column 5. However, other portions of US Patent No. 4,040,900 are also related to the invention.

The surfactants used in the process of the present invention include the following compounds: ethoxylated alkylphenols such as nonylphenoxypolyethoxyethanol, polyethylene glycols such as polyethylene glycol monooleate containing 400 oxyl groups and polyethylene glycol diilaurate containing 600 oxethyl groups, as well as other substances including certain ethoxylated phosphoric esters.

Preferred surfactants for use in the method of the invention are GAFAC RM510 and GAPAC RE610, both free acids of complex organic phosphoric acid esters manufactured by GAF Corporation.

Water-soluble polymers which are useful cationic agents of the invention, comprising water-soluble vinyl addition polymers (homopolymers and copolymers) having a molecular weight ranging from 10,000 to 1,000,000, in which at least 10% by weight and up to 100% % by weight of the merer content of the polymer consists of repeating units of cationic monomer or cationically modified monomer or monomers. Most preferably, 20 to 75% by weight of the repeating units of the polymer or copolymer are derived from cationic or cationically modified monomers.

Polymers suitable for use in the present invention typically have a molecular weight of greater than 10,000 and less than 1,000,000. Polymers of this type should generally be water-soluble and preferably have a molecular weight in the range of 20,000 to 750,000. the molecular weight of the polymers used is from 50,000 to 150,000.

Examples of non-limiting polymers that can be used in the process of the present invention include the following copolymers and homopolymers: optionally quaternized copolymer of acrylamide and dimethylaminoethyl acrylate, copolymer of acrylamide and diethylaminoethyl acrylate, quaternized copolymer of acrylamide and diethylaminoethyl acrylate and dimethylaminoethyl acrylate, , a quaternized copolymer of acrylamide and dimethylaminoethyl methacrylate, a copolymer of acrylamide and dialkyldimethalammonium chloride, polydiallyldimethylammonium chloride, polydimethylaminoethyl methacrylate and its quaternary derivatives, polymethacrylamidopropyltrimethylamonoimethyl methacrylamide and copolymer of acrylamide amide.

Also useful are acrylamide polymers and copolymers that have been subjected to a Mannich reaction with formaldehyde and secondary lower alkylamines. These polymers may or may not be quaternized.

As can be seen, all polymers useful in the present invention have a cationic charge and are water-soluble. Many of them are prepared from vinyl addition polymers, although polycondensates can generally be used. Since the number of possible cationically charged monomers capable of providing a water-soluble polymer is substantially unlimited, it is expected that all water-soluble cationic-charged vinyl addition polymers having a molecular weight in the range of 10,000 to 1,000,000 will exhibit cured effect, these polymers cannot be limited to the substances listed in the above cited review.

The polymers used may, as already mentioned, be copolymers or even terpolymers of various vinyl addition monomers. Although the preferred nonionic monomer used in the preparation of the copolymers useful in the present invention is acrylamide, other nonionic monomers such as methacrylamide and even anionically charged monomers such as acrylic acid, methacrylic acid, various sulfonated water-soluble vinyl can also be used addition monomers, etc.

The polymers used according to the invention may be in the form of water-in-oil emulsions (such as those described in U.S.R. 28,474 and 28,576), in the form of dry powders or dilute aqueous solutions. In order to use these polymers in the emulsification of ASA-based sizing agents by the process of the invention, an aqueous solution must first be prepared from the polymers. In the case of water-in-oil emulsion vinyl polymer emulsions, the water-soluble surfactants used to invert the water-in-oil emulsions have no detrimental effect on the activity of the polymer used to emulsify the ASA-based sizing agent. When a polymer solution is prepared from a water-in-oil polymer emulsion, a suitable method or device for preparing the solution is disclosed, for example, in US Patent No. 4,057,223 relating to a mixing device.

Depending on the molecular weight and the cationic charge of the polymer, 0.01 to 25%, preferably 0.01 to 10% by weight of the resulting sizing emulsion added to the pulp may be a polymer.

The ASA emulsions of the invention added to the pulp suspension typically contain up to 99.9% by weight of water.

0.01 to 50% by weight of ASA;

0.001 to 25.0% by weight of a water-soluble polymer.

Preferably, these emulsions contain up to 99.9% water,

0.01 to 40% ASA and

0.010 to 10% polymer.

Most preferably, the ASA emulsions contain 0.01 to 7.5, and more preferably 0.01 to 5.0% by weight of the polymer.

Thus, the polymers are used to prepare ASA-based sizing dispersions or emulsions.

The polymer of the present invention can be used to emulsify ASA or can be added to preformed ASA emulsions. In any case, the polymer enhances the effect of the emulsion compared to emulsions not containing the polymer. When the polymer is added to already formed ASA emulsions, conventional emulsifiers must be used in addition to the polymer. When it's. of the polymer used during the formation of the emulsion ASA, no additional emulsifier is required.

The invention is illustrated in more detail in the following examples which also include tests of performance. The examples are not limiting, but merely illustrate the invention. The polymers mentioned below are either commercial products available on the market or are substances prepared in the following form.

Example 1

DMAEM-MeCl Quat, MAPTAC and polyDADMAC acrylamide solution copolymers having a molecular weight ranging from 10,000 to 400,000 are tested as emulsifiers and retention agents for ASA. These novel sizing compositions are compared to conventional ASA emulsions in water or cationic starch if regarding particle size of ASA, physical stability of the emulsion and sizing effect. A description of these polymers is given in Table I.

An ASA emulsion in water is prepared by mixing 95 parts of distilled water and 5 parts of ASA in an Eberbach semi-microemulsion cup. The mixture dispersed for 3 minutes at high speed. The emulsion formed is diluted with distilled water to a solid ASA content of 0.5% and is used in this form in Example 1. An ASA emulsion in cationic starch is prepared by first hydrating 5 parts of pregelatinized starch (cationic potato starch) in 95 parts. water and then stirred for 30 minutes. The sizing emulsion is then prepared by mixing 75 parts of a starch solution with 25 parts of ASA in an emulsion cup, dispersing for 20 seconds. The resulting emulsion is diluted to a solid ASA content of 0.50% and used in this form in Example 2. Finally, the ASA emulsion in vinyl addition polymers is prepared by dispersing the ASA in a polymer solution at a dry weight ratio of 5: 1. in the above manner to a dry matter content of ASA 0.50 Examples 3 to 8 illustrate a new use of these addition polymers.

ASA emulsions are separately tested in a pulp suspension containing 50% recycled corrugated board and 50% recycled newsprint. The suspension has the following parameters: consistency 0.5%, Canadian Standard Preeness 400, pH 7.5, temperature 25 ° C, additive h, hydrated aluminum sulfate .12.5 ppm. Hand sheets with a basis weight of 0.074 kg / m 2 are manufactured according to the ΤΛΡΡΙ T-205 procedures. The above sizing compositions are added to the pulp suspensions shortly before forming the wet web at a dose of 0.10 to 0.15%, based on the weight of the paper. The test sheets are immediately dried in a rotary drum to a 98% solids content. The results are shown in Table I.

Table I

The description of the polymer reads

Weight Molecular Weight · ¹ * calculates the ratio to the limit viscosity number

AND quaternized diallyldimethylammonium chloride - 82 000 В quaternized diallyldimethylammonium chloride «. 235 ООО C acrylamide-DMAEM methyl chloride kvat. 75: 25 40 ООО D acrylamide-DMAEM methyl chloride kvat. 75: 25 210 ООО E and covered me with d-MAPTAČ 75: 25 50 ООО P acrylic lamid-МАРТАC 75: 25 380 ООО

T and b u 1 к а I - continuation Ex. Environment for Weight Prámerná physical stability číalo emulsifying the sizing agent ² ratio size emulsion ^ (form) žídla к particle e- solid- mulze environment (/ um)

1 Distilled water - 2 to 10 unstable - 2 separate phases 2 cationic potato starch (STALOK 500) ³ 5: 1 1 to 2 unstable, settled precipitate 3 polymer A 5: 1 0.5 to 2 unstable, 2 separate phases 4 polymer В 5: 1 1 to 2 permanent 5 polymer C 5: 1 1 to 3 permanent 6 polymer D 5: 1 0.5 to 2 permanent 7 polymer E 5: 1 1 to 2 permanent 8 polymer P 5: 1 1 to 2 permanent T a b u 1 к a I - continued Example number Test of sizing agent acid ink penetration (s) ^ depending on the amount contained on the pulp solids (% by weight) 0.100% 0.150% 1 2 15 Dec 2 157 377 3 191 392 4 • 263 434 5 116 249 6 157 322 7 71 204 8 135 278

The viscosity values for determining the limit viscosity number were measured in 1M sodium nitrate solution at 30 ° C. Molecular Weight (M) calculated from the Viscosity Limit Number using the Mark-Houwink equation: ^ J - KM ² papíru Commercially available paper-grade alkenyl succinic anhydride ^ Available from AEStaley, Decatur, Illinois

4] physical form of emulsion after one week of aging at room temperature ^ Hercules sizing tester, tested at 80% reflectance, using 1% formic acid and 1.25% test ink containing naphthol green

Example 2

Vinyl addition polymers such as acrylamide copolymers in DMAEM-MeCl kvat. or MAPTAC and polyDADMAC are evaluated as excipients for the emulsification and retention of ASA. The novel sizing compositions are compared with conventional ASA emulsions in water or cationic starch in terms of particle size of the ASA emulsion, the physical stability of the emulsion after aging and the sizing effect. The molecular weight of these polymers ranges from 10,000 to 400,000. A description of these polymers is given in Table II.

An ASA emulsion in water is prepared by mixing 95 parts of distilled water and 5 parts of ASA in a laboratory 226 ml Osterizer bottle. The mixture was dispersed by high speed stirring for 3 minutes. The emulsion formed is diluted with distilled water to a solids content (ASA) of 0.50% and used in Example 9. An ASA emulsion in cationic starch solutions is prepared by first hydrating 5 parts of pregelatinized cationic potato starch in 95 parts water. , while stirring for 30 minutes. The sizing emulsion is then prepared by mixing 95 parts of a starch solution with 5 parts of ASA in an Osterizer vessel, dispersing the size for 25 seconds. The resulting emulsion is diluted to a solid ASA content of 0.50% and used in Example 10. An ASA emulsion in vinyl addition polymers is prepared by dispersing ASA in polymer solutions at an ASA to polymer ratio of 1: 1 in an Osterizer vessel for 5 to 30 times. seconds. The resulting emulsions are then diluted, like other emulsions, to a solid ASA content of 0.50%. A new use of these vinyl addition polymers is given in Examples 11-16.

Each ASA emulsion is tested separately in a pulp suspension of 50% bleached softwood kraft pulp 50% bleached hardwood kraft pulp. Other parameters of the pulp are: consistency 0.5

Standard Freeness 330, pH 7.3, 27 ° C. In accordance with the TAPPI T-205 procedures, test sheets of 0.074 kg / m < 2 > The above sizing agents are added to the pulp suspension shortly before forming a wet web of 0.20% ASA, calculated as the dry matter of the ASA relative to the dry matter of the paper. Immediately after manufacture, the handsheets are squeezed to a residual moisture content of approximately 50% and dried in a rotary drum dryer to 93% dry matter. The results are shown in Table II below.

Table II Description Polymer Description Weight Molecular weight ^ * calculates čení ratio limit viscosity akrylami- Numbers

du ke kvat. product

AND diallyldimethylammonium chloride kvat. - '82 000 В diallyldimethylammonium chloride кvat. - 235 000 P acrylamide - MAPTAC 75 : 25 380 000 G acrylamide - MAPTAC 50 : 50 140 000 D acrylamide - DMAEM methyl chloride kvat. 75 : 25 210 000 II acrylamide - DMAEM methyl chloride kvat. 50 : 50 90 000

Table II - continued

Ex. ASA Emulsion Number Environment *

Mass ratio of ASA to solid environment

Average particle size ASA (µm) physical stability of emulsion 4 (form) distilled

water 1 to 5 unstable - 2 separate phases 10 cationic potato Starch (STALOK 500) ³ 1 : 1 1 to 3 unstable - deposited precipitate 11 polymer A 1 : 1 1 to 3 unstable - 2 separate phases 12 polymer В 1 : 1 1 to 3 permanent 13 polymer P 1 : 1 0.5 to 2 permanent 14 polymer G 1 : 1 1 to 2 permanent 15 Dec polymer D 1 ; 1 0.5 to 1 permanent 16 polymer H 1 : 1. 0.5 to 2 permanent

Table II - continued

Ex. Neutral ink penetration test ^ (s) at ASA content

Number 0.40%, based on dry weight of pulp

9 1 10 273 11 9 12 5 13 71 14 246 15 Dec 227 16 17

The viscosity values for determining the limit viscosity number were measured in 1M sodium nitrate solution at 30 ° C. Molecular weight (CM) calculated from the limit viscosity number Z (J) using the Mark-Houwink equation of ³ К.

η

Commercially available paper grade alkenylsuccinic anhydride. Available from A.E. Staley, Decatur, IllinoiB ^ Physical form of emulsion after one week of aging at room temperature ^ Hercules sizing tester, tested at 80% reflectance using 1% sodium formate (pH 7) and 1.25% naphthol test ink green

Example 3.

The following example illustrates the new use of acrylamide copolymers of the DMAEM-MeSQ, DMAEA-MeSQ, DEAEA-MeSQ and DADMAC type having a molecular weight of more than 1,000,000 as emulsifiers and retention agents for ASA-based sizing agents. The resulting alkenylsuccinic anhydride emulsions are compared with ASA in water emulsions and conventional emulsions made using cationic starch in terms of particle size and sizing effect.

The ASA comparative emulsion in water is prepared by mixing 95 parts of distilled water in 5 parts of ASA in an Eberbach semi-microemulsion vessel, dispersing the sizing agent for 60 seconds. The resulting emulsion was diluted to an ASA content of 0.50% (dry weight) with water and used in Example 17. An ASA emulsion in cationic starch was prepared by first hydrating three parts of the pregelatinized potato starch with97 parts of cold water with stirring for 30 minutes. for 30 minutes. Two emulsions were then prepared using a semi-microemulsion container, iodine and a weight ratio of ASA to starch (dry matter ratio) of 10: 1 and the other 3: 1 by dispersing 30 parts of ASA in 70 parts of 3% cationic Starch or 9 parts of ASA in 91 parts of 3% cationic. starch. The resulting emulsions were diluted to an ASA (dry matter) content of 0.50% with water and used in Examples 19 and 20.

Polymer solutions are prepared by hydrating 0.6 parts of polymer dry matter in 99.9 parts of water, with hydration being carried out with stirring for sufficient time to complete. The acrylamide copolymers listed below are used. An emulsion having a weight ratio of ASA to polymer (dry solids ratio) of 10: 1 and 3: 1 was then prepared using a semi-microemulsion container by dispersing both 6 parts of ASA in 94 parts polymer solution at 0.6% polymer solids and 1.8 of ASA in 98.2 parts of polymer solution at a concentration of 0.6% polymer dry weight.

Then further dilution is made to an ASA (dry matter) content of 0.5% by weight. The following example illustrates the advantages provided by this invention: the ability of these cationic water-soluble acrylamide copolymers to form an ASA emulsion and to give ASA emulsion particles a substantive nature with respect to cellulose.

Each of the following ASA emulsions is added separately to a 0.5% consistency pulp suspension having the following composition: 40% bleached kraft pulp of hardwood, 40% bleached kraft pulp of softwood, and 20% calcium carbonate. Susoenze has a Canadian Standard Preeness of 300 and a pH of 8.2. According to the TAPPI T-205 processes, hand-made test sheets with a basis weight of 0.074 kg / m 2 are made from paper stock. ASA emulsions are added to the pulp suspension shortly before forming a wet paper web at a dose of 0.250 and 2.00%, based on the dry weight of the pulp. The hand sheets are immediately dried in a rotary drum drier to a solids content of 98% (residual moisture content of 2%). The results are shown in Table III.

This example clearly illustrates the novel use of cationic vinyl addition copolymers as excipients for emulsifying ASA and emulsion retention aids. Improved water resistance is achieved compared to conventional ASA emulsions in water or cationic starch solution. The improved water resistance achieved according to the invention cannot be explained simply by improving the retention in the paper machine, as shown by the separate additions of the cationic polymers to the paper treatment means.

However, the use of polymers of this order of molecular weight leads to the formation of sticky deposits and unstable emulsions. Further research, exemplified in this description, has shown that polymers having a molecular weight greater than 10,000 and less than 1,000,000, and preferably having a molecular weight in the range of 20,000 to 750,000, have substantially the same effect as polymers with higher molecular weight. molecular weight. In addition, the use of polymers having a molecular weight in the preferred range of 50,000 to 150,000 leads to the elimination of the deposition mentioned above and increases the stability of the thus prepared ASA emulsions.

СЗ 264115 В2

Table 1 and III

Designation Polymers Acrylamide copolymer kvat. Molecular weight ^ * calculated from the viscosity limit number Form AND DMAEA, methyl chloride quat. 5 700 000 dry powder J 12 wt. DEAEA, monomethylsulfate, salt 9 200 000 dry powder К 12.5 wt. DMAEM, dimethylsulfate quat. - dry powder L 35 wt. DMAEM, monomethylsulfate quat. 8 900 000 emulsion M 28.6 wt. DADMAC 4 300 00 emulsion

Table III - continued

Ex. A medium for emulsifying glue sizing ^

Mass ratio of wedges - Average ratios to solid bone particles to emulsion media (yum)

Neutral ink penetration test ^ (s) as a function of sizing agent on pulp solids (% by weight)

0.250% 2.000%

17 Distilled water - 2 to 20 1 423 18 distilled water + wetting agent 1 to 4 1 255 19 Dec cationic potato. Starch 4OO ⁴ 3 - 1 1 to 2 310 - 20 May STALOK 400 ⁴ 10: ! 1 1 to 3 282 - 21 polymer I 3 - 1 1 to 3 656 - 22nd polymer J 3!  1 1 to 3 426 - 23 polymer К 3 - 1 1 to 3 464 - 24 polymer L 10: : 1 0.5 to 4 468 - 25 polymer M 10: 1 0.5 to 2 313

CS 264115 31

The viscosity values for 3 determination of the limit viscosity number were measured in 1 M sodium nitrate solution at 30 ° C. Molecular weight (M) is calculated from the limit viscosity number (^) using the Mark-Houwink equation: (^).

Commercial grade alkenylsuccinic anhydride of paper grade

Type of wetting agent - ethoxylated nonylphenol, dosed in an amount of 5.0% by weight, based on the sizing agent. Product of A.E. STALEY, Decatur, Illinois, USA

5 Hercules sizing tester, with reflectance%

DMAEA = dimethylaminoethyl acrylate

DEAEA and diethylaminoethyl acrylate

DMAEM = diinethylaminoethyl methacrylate

DADMAC »diallyldimethylammonium chloride

Claims (1)

SUBJECT OF THE INVENTION 1. Emulsion type emulsion based on alkenylsuccinic anhydride, for use in the manufacture of paper-based paper products, consisting of an emulsion containing 50 to 99.9% by weight of water, 0.01 to 40% by weight of alkenylsuccinic anhydride and 0.0001 to 10.0% by weight A cationic reagent comprising a water-soluble cationic vinyl addition polymer having a molecular weight ranging from 10,000 to 1,000,000 as the cationic reagent. O The sizing agent of claim 1, wherein the water-soluble vinyl addition polymer having a molecular weight in the range of 10,000 to 1,000,000 comprises at least 10 and up to 100% by weight of the total polymer content derived from cationic or cationic modified vinyl edition monomers. . 3. Sizing agent according to claim 1 or 2, characterized in that the cationic or cationic modified vinyl addition monomer is selected from the group consisting of diallyldimethylammonium chloride, methacrylamidopropyltrimethylammonium chloride, dimethylaminoethyl methacrylate, quaternized derivatives of dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, acrylamide, formaldehyde and lower secondary amine and quaternized derivatives of the Mannich reaction products of acrylamide, formaldehyde and lower secondary amine. 4 < The composition according to claim 1, 2 or 3, characterized in that the polymer is present in the sizing emulsion based on alkenylsuccinic anhydride in an amount of 0.01 to 5.0% by weight, calculated as the dry weight of the polymer.