JPH05302298A - Improving agent for paper surface quality - Google Patents

Abstract

PURPOSE:To obtain an improving agent having excellent effects on improving surface strength, inner strength and water resisting property of paper by polymerizing an acrylamide compound and a vinyl monomer such as an alpha, beta unsaturated monocarboxylic acid as essential components. CONSTITUTION:In the presence of a urea compound (e.g. urea, etc.) (A) an acrylamide compound (e.g. acrylamide, etc.) and (B) at least one vinyl monomer such as an alpha, beta unsaturated monocarboxylic acid (e.g. acrylic acid, etc.), an alpha, beta unsaturated dicarboxyl acid (e.g. maleic acid, etc.), an unsaturated sulfonic acid (e.g. styrenesulfonic acid, etc.) and their salts, etc. are, as essential components, subjected to react in the presence of sodium hypophosphite and ammonium persulfate in an aqueous medium under introducing nitrogen at temperature raised to 80 deg.C for two hours to obtain the objective improving agent for paper surface quality capable of improving surface strength, inner strength, water resisting property of paper, etc., by outer base addition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface paper quality improving agent which exhibits excellent effects in improving the surface strength, internal strength and water resistance of paper.

[0002]

2. Description of the Related Art In recent years, the development of printing technology has been remarkable, and with the increase in printing speed and quality, printing aptitude such as high surface strength, internal strength and water resistance is required. Has become. In order to meet these demands, chemicals are internally added (added to an aqueous pulp slurry) or externally added (coated on the surface of paper). Of these, internal addition does not have a sufficient yield of chemicals, and external addition has a yield of almost 100%, which directly affects the surface of the paper.
It is known to be more advantageous.

The surface paper quality improver added to increase the surface strength of the paper and improve the printability is conventionally starches such as starch, oxidized starch and cationized starch, carboxymethyl cellulose (hereinafter abbreviated as CMC). ) Etc., polyvinyl alcohol (hereinafter abbreviated as PVA) and natural or synthetic water-soluble polymers such as anionic polyacrylamide are used for the surface coating, and oxidized starch is most often used among them. .. However, starches, PVA
The type requires a cooking step when it is used, has poor workability, and has various operational problems such as foaming and dirt during coating. In addition, the aqueous starch solution has a problem of spoilage and aging.

On the other hand, as the acrylamide resin, a monomer such as acrylic acid or methacrylic acid or acrylonitrile which has a considerable solubility in water may be used in combination for normal radical copolymerization in water.
Alternatively, a water-soluble polymer modified with a carboxyl group by partially hydrolyzing acrylamide after or before aqueous solution polymerization has been proposed as a paper surface-treating agent mainly for the purpose of improving the surface strength (Japanese Patent Publication No. 43-275
No. 29), but its surface strength, internal strength, and water resistance improving effect are not sufficient.

As a similar technique, a reinforcing agent for pulp products comprising a copolymer obtained by copolymerizing acrylamides with acrylonitrile and acrylic acid or its alkali salt in the presence of urea (Japanese Patent Publication No. 61-3124).
No. 0), but this is an internal additive different from the external additive of the present invention. The wire is clogged with internal addition, workability is deteriorated due to roll stains, and damp due to blanket stains. It was proposed for the purpose of preventing product picking and breakage. Therefore, it can be said that this is obviously different from the external additive that is coated after the paper layer of the present invention is formed and improves the surface strength, internal strength and water resistance of the paper.

[0006]

Under such circumstances, the above-mentioned existing surface paper quality improver cannot be said to be sufficiently satisfying the recent demand for a high degree of surface paper quality improvement, and the surface of the paper is not sufficiently satisfied. It was necessary to improve the problems in printing due to lack of strength and internal strength, and further lack of water resistance. In particular, regarding the neutral paper whose production has been increasing recently, it is the current situation that no effective one is found yet, and the appearance of a high-performance surface paper quality improving agent that improves various surface paper quality in a balanced manner has been desired. ..

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to meet the demand, and as a result, in the presence of ureas, acrylamides (a) and α, β unsaturated monocarboxylic acid, α, When the surface paper quality improver of the acrylamide resin obtained by polymerization using β-unsaturated dicarboxylic acid, unsaturated sulfonic acid or salts thereof (b) as an essential component is used alone or in combination with a water-soluble polymer, The inventors have found that the quality of various surface papers can be improved in a well-balanced manner compared to the case where a polymer is used alone, and excellent effects are exhibited not only in acidic papers but also in neutral papers, and the present invention has been completed.

That is, the present invention relates to acrylamides (a) and α, β unsaturated monocarboxylic acids in the presence of ureas,
Improvement of surface paper quality of acrylamide resin obtained by polymerizing at least one vinyl monomer (b) selected from the group consisting of α, β unsaturated dicarboxylic acids, unsaturated sulfonic acids, and salts thereof as an essential component To provide the agent.

Next, the present invention will be described in detail. Examples of ureas used in the present invention include urea, thiourea, and ethylene urea, and urea is particularly preferable.

As acrylamides, in addition to acrylamide and methacrylamide, N-ethyl (meth) acrylamide, N-methyl (meth) acrylamide, N, N
-N-substituted alkyl acrylamides such as dimethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nt-octyl (meth) acrylamide and the like can be mentioned, and these can be used alone or in combination of two or more.

Examples of the α, β unsaturated monocarboxylic acid and salts thereof include acrylic acid, methacrylic acid and their sodium acids, potassium salts, ammonium salts and the like. Examples of the α, β unsaturated dicarboxylic acids and salts thereof include maleic acid, fumaric acid, itaconic acid, citraconic acid and their sodium salts, potassium salts, ammonium salts and the like. Examples of unsaturated sulfonic acids and salts thereof are styrene sulfonic acid, vinyl sulfonic acid,
Allylsulfonic acid and salts thereof, such as sodium salt, potassium salt, ammonium salt and the like can be mentioned.

In addition to these anionic monomers, polymerizable cationic monomers such as dimethylaminopropyl (meth) acrylamide and quaternary compounds thereof, or styrene, methyl vinyl ether, (meth) in an amount that does not impair the water solubility of the resin. ) An alkyl ester of acrylic acid having 1 to 8 carbon atoms, a 2-hydroxy ester, a glycidyl ester or the like may be used together as a copolymerization component.

The surface paper quality improving agent of the present invention exerts an excellent effect in improving the surface strength, internal strength, water resistance and the like of acid paper / neutral paper, etc. When the used surface paper quality improver is used for neutral paper, it is particularly excellent in improving the internal strength of the neutral paper. The internal strength of the neutral paper has been improved by internally adding polyacrylamides, but the degree is not sufficient. Although it is possible to supplement the performance of the internally added chemicals by external addition, that is, coating, until now, none of the performances was sufficiently satisfactory. The surface strengthening agent using itaconic acid of the present invention satisfies the requirements regarding the internal strength of the neutral paper.

Other cationic monomers include 2-hydroxy-N, N, N, N ', N'-pentamethyl-
N '-(3- (meth) acryloylaminopropyl)-
1,3-propanediammonium dichloride, 2-hydroxy-N-benzyl-N, N-diethyl-N ',
N'-dimethyl-N '-(2- (meth) acryloyloxyethyl) -1,3-propanediammonium dibromide, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth ) Acrylamide, N-ethyl-N, N-dimethyl- (2-
(Meth) achloroyloxyethyl) ammonium bromide, N-benzyl-N, N-dimethyl- (3- (meth) acryloylaminopropyl) ammonium chloride, diallylamine, vinyl pyridine, vinyl imidazole and the like can be mentioned.

A crosslinking agent may be used in addition to these monomers. As the cross-linking agent, any cross-linking agent conventionally used for polyacrylamide resins can be used. As an example, ethylene glycol di (meth) acrylate,
Di (meth) acrylates such as diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, methylenebis (meth) acrylamide,
Bis (meth) acrylamides such as ethylene bis (meth) acrylamide and hexamethylene bis (meth) acrylamide, epoxy acrylates, divinylbenzene, urethane acrylates, diallyl phthalate, diallyl malate, triallyl cyanurate, triallyl isocyanurate , Dimethylol urea, dimethylol ethylene urea, other polymethylol urea, methylol ethylene urea, dimethylol glyoxal monourein, dimethylol glyoxal diurein, dimethylolurone, dimethylol propylene urea, 1,3-
Bis- (hydroxymethyl) tetrahydro-5-hydroxy-2-pyrimidinone, dimethyloltriazone, dimethylolmelamine and other polymethylolmelamine,
Examples thereof include polymethylol compounds such as polymethylolacetoguanacin and polyaldehyde compounds such as glyoxal, glutaraldehyde, and dialdehyde starch.

Polymerization of the acrylamide resin of the present invention is carried out in the presence of ureas in the presence of a suitable polymerization initiator 40 to 100.
It is carried out at a reaction temperature of ° C and a reaction time of 1 to 10 hours. The urea / monomers weight ratio is 5-60% / 95-40%, preferably 30-50% / 70-50%. Whether the amount of urea is larger or smaller than this range is not preferable in terms of balance of surface strength, internal strength, water resistance and the like.

Known polymerization initiators are used. As the radical polymerization initiator, a water-soluble catalyst such as sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, and a cerium salt is used in an amount of 0.0 based on the total weight of the monomers.
Use 1-5% by weight. Further, redox polymerization can also be carried out using a reducing agent such as dimethylamine, sodium hydrogen sulfite, sodium formaldehyde sulfoxylate. Moreover, you may use a well-known chain transfer agent as needed.

Examples thereof include allyl alcohol, allylamine, allyl compounds such as sodium allylsulfonate, mercaptoethanol, thioglycolic acid or its alkali metal salts or ammonium salts, isopropyl alcohol, sodium hypophosphite and the like.

The acrylamides (a) and at least one vinyl monomer (b) selected from the group consisting of α, β unsaturated monocarboxylic acids, α, β unsaturated dicarboxylic acids, unsaturated sulfonic acids, and salts thereof. The weight ratio is 99.5-5
0% / 0.5-50%, preferably 98-85% / 2
15%.

Acrylamides (a) in the presence of ureas
And at least one vinyl monomer (b) selected from the group consisting of α, β unsaturated monocarboxylic acid, α, β unsaturated dicarboxylic acid, unsaturated sulfonic acid, and salts thereof, as an essential component. The acrylamide resin obtained may be used alone or in combination with a water-soluble polymer.

As the water-soluble polymer, starch, oxidized starch,
Examples thereof include starch derivatives such as cationized starch, cellulose derivatives such as carboxymethyl cellulose, and polyvinyl alcohol.

The surface coating liquid containing the surface quality improver for paper of the present invention comprises an acrylamide (a) and α, β unsaturated monocarboxylic acid, α, β unsaturated dicarboxylic acid, and A single solution of an acrylamide resin obtained by polymerizing at least one vinyl monomer selected from the group consisting of saturated sulfonic acids and their salts (b) as an essential component, or a mixed solution with a water-soluble polymer. ..

The mixed solution is prepared by mixing an aqueous solution of the acrylamide resin and the aqueous solution of the water-soluble polymer, or by mixing an aqueous solution of the acrylamide resin and the dispersion of the water-soluble polymer and then cooking. You can Although it can be mixed in any proportion, it is preferable that the acrylamide resin is 10% by weight or more from the viewpoint of improving the surface paper quality such as internal strength, surface strength and water resistance in a well-balanced manner.

The coating liquid of the present invention contains a surface sizing agent, an anti-slip agent,
Additives such as antiseptics, defoamers, viscosity modifiers and dyes may be used in combination. The concentration of the coating liquid is 0.2 to 10%, and the viscosity is 1%.
3 to 300 centipoise (cp) under conditions of 5 ° C and 60 rotations
Those of s) are preferable, and those of 3 to 100 cps are most preferable for coating.

In order to apply the surface coating liquid of the present invention to paper or paperboard, a method of using a size press, a gate roll coater, a blade coater or a calender is preferable. It can also be applied by a bar coater, knife coater, air knife coater, or the like.

Further, the coating liquid of the present invention is used for various base papers such as coated base papers (acidic papers, neutral papers), newsprint papers, liners, coated balls, printing writing papers, foam papers, PPC papers, ink jet papers, and thermal papers. Can be applied to.
Although the sizing degree of the base paper is arbitrary, it is desirable to use an internal sizing agent for the purpose of adjusting the liquid absorption amount of the base paper when coating is performed using a size press or the like.

[0027]

The present invention will be described below with reference to examples, but the present invention is not limited to these examples. For convenience, monomers and the like are abbreviated as follows.

AAm: Acrylamide AAc: Acrylic acid NaSS: Sodium styrenesulfonate DMAAm: N, N-Dimethylacrylamide SVS: Sodium vinylsulfonate AMPS: Sodium 2-acrylamido-2-methylpropanesulfonate MAAc: Methacrylic acid MA: Methyl Acrylate MAn: Maleic anhydride EUR: Ethylene urea DM: N, N-Dimethylaminoethylmethacrylate IA: Itaconic acid FA: Fumaric acid The measurement was performed according to the following method.

Internal strength: Scott bond method; measured using an internal bond tester (manufactured by Kumagai Riki Kogyo Co., Ltd.) under the conditions of an adhesion pressure of 1 kg / cm ² and 30 seconds. Surface strength: Dry pick; RI printing tester, nip width 1
0 mm ink; FINE INK. (Dainippon Ink and Chemicals, IGT printability test) V. = 18 or 20 wet pick; RI printing tester, nip width 10 mm,
Molton roll ink; T.S. of CAPS G (Dainippon Ink and Chemicals, offset) ink. V. = 8 In each case, the peeled state after printing was observed with the naked eye, and 5 was evaluated as excellent and 1 was evaluated as inferior to perform a 5-level evaluation.

Size degree: Steckigt method; JIS P-8
122-1976 Cobb size degree (10 seconds); JIS P-8140-19
76 drop test: 5 μl of ion-exchanged water was dropped on the surface of the coated paper, and the time until penetration was measured.

Production Example In a 1 liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 650 g of water and 8 of urea.
3.0 g (urea is 40% by weight of the total of urea and monomers).
50% acrylamide aqueous solution 238.9 g (96 mol%), 98% acrylic acid 5.15 g (4 mol%), 5%
After charging 6.31 g of an aqueous solution of sodium hypophosphite, 7.99 g of a 5% ammonium persulfate aqueous solution was added, and the temperature was raised to 80 ° C. under introduction of nitrogen gas, and the reaction was carried out for 2 hours.

49.6 g of ion-exchanged water was added to the obtained polymer.
Solid content 19.2%, viscosity 1930 cps, p
A clear aqueous solution of H5.8 was obtained. This is designated as resin A.
Furthermore, in Production Example 1, polyacrylamide polymers B to M and a to c were produced by appropriately changing the kind of the monomer, the amount used, the polymerization concentration, the amount of the initiator, etc., and the physical properties thereof are shown in Table 1. In Table 1, the viscosity is a value measured by a Brookfield viscometer at 25 ° C.

[0033]

[Table 1]

Examples 1 to 6 The resin aqueous solutions A to F synthesized in Production Examples were diluted with water, and a surface sizing agent Hercon S20 (a surface sizing agent manufactured by Dick Hercules) was added to the mixture to give a solid content of 1.75%. A liquid (0.1% by weight of Hacon S20 in the solution) was prepared.

The aqueous solution was mixed with high-quality neutral paper (basis weight: 77.0 g /
Test size press installed in m ² ) (made by Kumagai Riki Kogyo Co., Ltd.)
Coating on both sides (nip pressure 20 kg / cm, coating speed 1
(00 m / min, coating temperature: 50 ° C.), and dried with a drum dryer at 80 ° C. for 50 seconds. Coating amount is 0.65 ±
It was 0.03 g / m ² . After drying, 20 ℃, 65% RH
After leaving it in the constant temperature and humidity chamber for 24 hours, it was subjected to the test.
The test results are shown in Table 2.

Comparative Examples 1 to 4 Coating was carried out in the same manner as in Example 1 except that cooked MS3800 (oxidized starch manufactured by Japan Food Processing Co., Ltd.) and the aqueous resin solutions ac synthesized in Production Examples were used. , A test was conducted. The coating amount was 0.65 ± 0.03 g / m ² . The test results are shown in Table 2.

Examples 7 to 11 Resin aqueous solutions G to J and resin aqueous solutions G synthesized in Production Examples
A mixed aqueous solution of MS3800 cooked with (solid content ratio of 2/1) was diluted with water to prepare a 2.0% solid content solution.

The aqueous solution was mixed with high-quality acidic paper (basis weight: 73.3 g /
m ² ) test size press machine (made by Kumagai Riki Kogyo Co., Ltd.)
Coating on both sides (nip pressure 20 kg / cm, coating speed 1
(00 m / min, coating temperature: 50 ° C.), and dried with a drum dryer at 80 ° C. for 50 seconds. Coating amount is 0.68 ±
It was 0.03 g / m ² . After drying, 20 ℃, 65% RH
After leaving it in the constant temperature and humidity chamber for 24 hours, it was subjected to the test.

Comparative Examples 5 to 8 Coating and testing were carried out in the same manner as in Example 7 except that the cooked MS3800 and the resin aqueous solutions ac synthesized in the production examples were used. Coating amount is 0.68 ± 0.0
It was 3 g / m ² . The test results are shown in Table 3.

Examples 12 to 14 The resin aqueous solutions L to M synthesized in Production Examples were diluted with water to prepare liquids having a solid content of 2.0%. The aqueous solution (temperature: 50 ° C.) was applied to newsprint (basis weight: 44.9 g / m ² ) in No. 1 side coating with a bar coater No. 3 and a drum dryer at 80 ° C for 5
It was dried under the condition of 0 seconds. Coating amount is 0.27 ± 0.02g
/ M ² . After drying, it was left in a constant temperature and humidity room at 20 ° C. and 65% RH for 24 hours and then subjected to the test.

Comparative Examples 9 to 11 Coating and testing were carried out in the same manner as in Example 12 except that cooked MS3800 and the resin aqueous solutions a and c synthesized in the Production Example were used. The coating amount is 0.27 ± 0.
It was 02 g / m ² . The test results are shown in Table 4.

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

[0045]

INDUSTRIAL APPLICABILITY The present invention provides a surface paper quality improver capable of improving various kinds of surface paper quality by external addition, which has been particularly desired in recent years, and can be said to have a great industrial effect on the industry. ..

Claims (2)

[Claims] 1. A acrylamide (a) selected from the group consisting of α, β unsaturated monocarboxylic acids, α, β unsaturated dicarboxylic acids, unsaturated sulfonic acids, and salts thereof in the presence of ureas. A surface paper quality improver comprising an acrylamide resin obtained by polymerizing at least one vinyl monomer (b) as an essential component. 2. The surface quality improving agent according to claim 1, wherein the acrylamides (a) are at least one selected from acrylamide, methacrylamide, and N-substituted alkyl (meth) acrylamides.