JPH1136185A - Sizing composition for paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition that can suppress the stickiness of paper, shows excellent coating properties and can increase the degree of sizing and the burst index by using a polyvinyl alcohol resin and a ketene dimer. SOLUTION: This sizing composition contains (A) a polyvinyl alcohol resin, preferably a carboxyl group-containing polyvinyl alcohol resin, and (B) a ketene dimer. The average polymerization degree of the component A is preferably 100-10,000 and the content of the carboxyl group is 0.1-10 mol.% in the carboxyl group-containing polyvinyl alcohol. The component B is exemplified by the formula (R1 and R2 are independently from each other a hydrocarbon residue of 8-30 carbon atoms, preferably of 10-20 carbon atoms).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sizing agent composition for paper, and more particularly, to a sizing agent for paper which has excellent coatability and has little stickiness on the paper surface after processing (sizing). Agent composition.

[0002]

2. Description of the Related Art Conventionally, a vinyl ester resin, especially a polyvinyl alcohol resin, is coated on a paper surface in order to improve surface characteristics such as surface strength, smoothness, gloss and the like of paper, and a sizing agent for paper is used. Widely used as. Paper coated with such a sizing agent is usually passed through a calender roll in order to improve its gloss and smoothness. However, depending on the type of the sizing agent, the coated paper can be calendered (particularly in a high humidity atmosphere). This may cause paper to stick to the roll and cause paper breakage, and also cause problems such as paper breakage due to the sticking of paper to the blanket cylinder of the printing press due to the stickiness (splashing) of the sizing agent even during wet offset printing. Therefore, a paper sizing agent having low adhesiveness (stickiness) even when the paper is wet is desired. As a measure against such adhesiveness (stickiness), a water-soluble polyvinyl alcohol-based resin and a polychlorinated resin having a particle diameter of 10 μm or less are used. Aqueous resin liquid composed of vinyl resin powder and water (JP-A-53-61705) Publication) is disclosed.

[0003]

However, when the polyvinyl chloride resin powder is added, the strength of the surface paper strength, which is the characteristic of the polyvinyl alcohol resin, is reduced, or when the aqueous liquid becomes waste water. In addition, there are drawbacks such as difficulty in treating wastewater, and a paper sizing agent that can satisfy these drawbacks has been desired.

[0004]

In view of the above circumstances, the present inventors have conducted intensive studies and as a result, have found that a sizing agent for paper containing a polyvinyl alcohol resin (A) and a ketene dimer (B). The composition prevents the adhesiveness (stickiness) of the paper, is excellent in coating properties, and can also improve the size and strength of the paper. The polyvinyl alcohol-based resin (A) is a carboxyl group-containing polyvinyl alcohol. It has been found that when the resin is a system resin, the effects of the present invention can be particularly remarkably obtained, and the present invention has been completed.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below.
The polyvinyl alcohol-based resin (A) of the present invention is not particularly limited, and is not limited to partially saponified polyvinyl acetate,
The following saponified copolymers of a vinyl ester and a copolymerizable monomer can be used. Allyl esters of saturated carboxylic acids: allyl stearate, allyl laurate, allyl coconut oil, allyl octylate, allyl butyrate and the like. α-olefin ethylene, propylene, α-hexene, α-octene,
α-decene, α-dodecene, α-hexadecene, α-octadecene and the like. Alkyl vinyl ether propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, dodecyl vinyl ether, tetradecyl vinyl ether, hexadecyl vinyl ether, octadecyl vinyl ether and the like. Alkyl allyl ether propyl allyl ether, butyl allyl ether, hexyl allyl ether, octyl allyl ether, decyl allyl ether, dodecyl allyl ether, tetradecyl allyl ether, hexadecyl allyl ether, octadecyl allyl ether and the like. In addition, (meth) acrylamide, (meth) acrylonitrile, (meth) allyl sulfonate, ethylenically unsaturated sulfonate, styrene, vinyl chloride and the like can be used.

However, in the present invention, a carboxyl group-containing polyvinyl alcohol resin is preferable.
Hereinafter, such a carboxyl group-containing polyvinyl alcohol-based resin will be described in detail, but is not limited thereto. The method for producing the carboxyl group-containing polyvinyl alcohol resin is not particularly limited, and the resin can be produced by any method. For example, a method of obtaining a copolymer from an unsaturated monomer having a carboxyl group and a vinyl ester-based compound, and then saponifying the copolymer, a method of simply preparing a polyvinyl alcohol-based resin having a carboxyl group having an oxyalkylene group A method of graft-polymerizing a monomer may be mentioned, but the method is practical in terms of resin production and performance. Hereinafter, the following method will be specifically described.

Examples of the unsaturated monomer having a carboxyl group include ethylenically unsaturated dicarboxylic acids (maleic acid, fumaric acid, and itaconic acid) or ethylenically unsaturated carboxylic acid monoesters (monoalkyl maleate, fumaric acid). Monoalkyl ester, itaconic acid monoalkyl ester), or ethylenically unsaturated dicarboxylic acid diester (maleic acid dialkyl ester, fumaric acid dialkyl ester, itaconic acid dialkyl ester), or ethylenically unsaturated carboxylic anhydride (maleic anhydride,
Monomers such as (itaconic anhydride) or (meth) acrylic acid, and salts thereof, are preferably used. Ethylenically unsaturated carboxylic acid monoesters and salts thereof are preferably used.
Further, as the vinyl ester compound, vinyl formate,
Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caprate, vinyl laurate, vinyl versatate, vinyl palmitate, vinyl stearate and the like can be used alone or in combination, but vinyl acetate is particularly practical. .

In the present invention, in addition to the above-mentioned monomer having a carboxyl group and a vinyl ester compound during the polymerization, a monomer which can be copolymerized with the vinyl ester as described above is present in an amount of 50 mol% or less. At least polymerization may be performed. There is no particular limitation on the copolymerization,
A known polymerization method may be arbitrarily used, but usually, solution polymerization using an alcohol such as methanol or ethanol as a solvent is performed. In such a method, as a method of charging the monomer, first, the polymerization is started by charging the entire amount of the vinyl ester compound and a part of the carboxyl group-containing unsaturated monomer, and the remaining unsaturated monomer is added during the polymerization period. Arbitrary means such as a method of continuously or dividedly adding the ingredients, a method of batch charging, and the like may be used. The copolymerization reaction is carried out using a known radical polymerization catalyst such as azobisisobutyronitrile, acetyl peroxide, benzoyl peroxide, and lauroyl peroxide. The reaction temperature is selected from the range of 50 ° C. to the boiling point.

The copolymer obtained as described above is then saponified to form a carboxyl group-containing polyvinyl alcohol resin. The saponification is performed by dissolving the copolymer in alcohol and in the presence of an alkali catalyst. Examples of the alcohol include methanol, ethanol, and butanol. The concentration of the copolymer in the alcohol is 20 to
It is selected from the range of 70% by weight. As the saponification catalyst, it is necessary to use an alkali catalyst such as an alkali metal hydroxide or an alcoholate such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate and potassium methylate. It is necessary to use the catalyst in an amount of 1 to 100 millimoles equivalent to the vinyl ester compound.

In such a case, the saponification temperature is not particularly limited, but is usually preferably selected from the range of 10 to 70 ° C, more preferably 30 to 50 ° C. The reaction is usually carried out for 2 to 5 hours, and the preferred degree of saponification is 10 to 100 mol%.
Particularly preferably 50 to 100 mol%, particularly preferably 7 to 100 mol%
It is selected from the range of 0 to 100 mol%. When a vinyl alcohol component is contained, the present invention is not limited to the above-mentioned method. For example, a method in which an alkylene oxide is post-reacted with polyvinyl alcohol (partially saponified or completely saponified) can be used. Thus, a carboxyl group-containing polyvinyl alcohol-based resin is obtained. The content of such a carboxyl group is preferably 0.1 to 10 mol%, more preferably 0.5 to 5 mol%. If the amount is less than 0.1 mol%, the paper strength is low, and if it exceeds 10 mol%, the solubility of the sizing agent composition becomes poor, which is not preferable.

In the present invention, the average degree of polymerization of the (carboxyl group-containing) polyvinyl alcohol resin (A) is preferably from 100 to 10,000, more preferably from 300 to 3
If the average degree of polymerization is less than 100, the paper strength decreases and the printability becomes poor. If the average polymerization degree exceeds 10,000, the coatability and permeability of the sizing agent composition decrease, which is not preferable. . Next, as the ketene dimer (B) used in the present invention, any known ketene dimer can be used. The ketene dimer (B) is typically represented by the following general formula (1).

In the general formula (1), R ₁ and R ₂ each represent a hydrocarbon residue having 8 to 30 carbon atoms, preferably 10 to 20 carbon atoms. Examples of the hydrocarbon residue include a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group,
Alkyl groups such as pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group and eicosyl group, alkenyl groups such as decenyl group, tridecenyl group, hexadecenyl group, octadecenyl group and eicosenyl group, p-tert
Alkenyl groups such as -butylphenyl group, octylphenyl group, nonylphenyl group and dodecylphenyl group; alkyl-substituted cycloalkyl groups such as nonylcyclopropyl and dodecylcyclohexyl group; and aralkyl groups such as phenylethyl group. And an alkyl group is preferred. The above ketene dimers can be used alone or in combination of two or more.

The sizing composition for paper of the present invention comprises a polyvinyl alcohol resin (A) and a ketene dimer (B) (containing a carboxyl group) as described above.
The mixing ratio of these is not particularly limited, but the ketene dimer (B) is 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight, based on 100 parts by weight of the carboxyl group-containing polyvinyl alcohol resin (A). When the content is less than 0.1 part by weight, the tackiness does not decrease. On the other hand, when the content exceeds 50 parts by weight, the paper strength decreases and the printability becomes poor.

The paper sizing agent composition of the present invention thus obtained is generally used by dissolving it in water, but it can also be used in a solvent system. The type of the solvent is the characteristic of the (carboxyl group-containing) polyvinyl alcohol-based resin (A),
What is necessary is just to select suitably according to the content ratio of (A) and (B). For example, a solvent having a relatively low degree of saponification can be obtained in the form of a paste, so that the solvent used for polymerization or saponification may be used as it is, or solvent replacement may be performed if necessary. There is no particular limitation on the preparation of the coating liquid. In short, water and the above-mentioned (carboxyl group-containing) polyvinyl alcohol-based resin (A) and ketene dimer (B) may be mixed. The concentration may be appropriately adjusted according to the purpose. Particularly preferred concentration of the polyvinyl alcohol-based resin (A) is usually 0.1 to 40% by weight, more preferably 1 to 20% by weight in consideration of workability and the like. Selected from a range of degrees.

The sizing agent composition for paper of the present invention contains a carboxyl group-containing polyvinyl alcohol-based resin (A) and a ketene dimer (B) as described above. Water-proofing agents such as antifoaming agents, release agents, surfactants, preservatives, insect repellents, rust inhibitors, thickeners and other known additives can also be added. Other paper processing agents such as other conventionally known resins such as polyvinyl alcohol, starch, carboxymethylcellulose, acrylic latex, and SBR latex can also be mixed within a range not to impair. The paper on which the paper sizing agent composition of the present invention is coated is not particularly limited.For example, paperboard such as manila balls, white balls and liners, general high quality paper, medium quality paper, printing paper such as gravure paper, Upper / middle / lower grade paper, newsprint and the like are preferably used. In applying the paper sizing agent composition to such paper, any known method such as a size press coater method, a roll coater method, an airdactor method, a blade coater method, and a shim sizer coater method is employed.

The coating amount of the paper sizing agent composition is 0.1 to 5 g / m ² (in terms of solid content) of the (carboxyl group-containing) polyvinyl alcohol resin (A), particularly preferably 0.1 to 5 g / m ² . It is appropriate that the amount is about 5 to ³ g / m ² (same as above). Of course, not limited to the above method, the so-called internal sizing method of dissolving the paper sizing agent composition of the present invention in a pulp dispersion and making paper, or further powdery, fibrous paper sizing agent composition of the present invention. The paper sizing agent composition of the present invention can be applied to paper by any method such as mixing in paper.

The paper sizing composition of the present invention is mainly used as a clear coating agent as described above, but can also be suitably used as a binder for pigment coating. Known pigments such as kaolin, diatomaceous earth, titanium oxide, iron oxide, and satin white are used. In such a binder, there is no concern about clay shock (a phenomenon in which the pigment is aggregated when the binder is added in a state where the pigment is dispersed), which has been a problem in the conventional pigment coating, and the pigment dispersibility is extremely low. Demonstrate excellent effects.

[0018]

The present invention will be specifically described below with reference to examples. In the examples, “parts” and “%” are based on weight unless otherwise specified. Example 1 [Preparation of carboxyl group-containing polyvinyl alcohol-based resin (A)] A polymerization vessel was charged with 500 parts of vinyl acetate, 3.4 parts of maleic acid, and 85 parts of methanol, and the system was heated in a nitrogen stream while stirring. After heating and refluxing at 60 ° C. for 30 minutes, azobisisobutyronitrile was added to vinyl acetate at a concentration of 0.0
8 mol% was added, polymerization was carried out for 6 hours, and after the reaction was completed, methanol vapor was blown in to remove unreacted monomers to obtain a methanol solution of the copolymer. Next, the obtained methanol solution was diluted to 40% with methanol, and the mixture was heated to 30 ° C. and neutralized with sodium hydroxide. Further, sodium hydroxide is added to the vinyl acetate in the copolymer in an amount of 20 mmol% to effect saponification, and the obtained saponified product is filtered, dried at 70 ° C., and dried at a carboxyl group-containing polyvinyl alcohol resin (degree of saponification). 99.1 mol%, average degree of polymerization 1400) (A) was obtained.

5.8 parts of the above carboxyl group-containing polyvinyl alcohol resin (A) and 0.2 parts of octadecyl ketene dimer (B) [weight ratio (A) / (B) = 100]
/3.4] was dissolved in 94 parts of water to obtain a sizing agent composition. The composition was size-pressed onto acidic paper having a basis weight of 60 g / m ^{2 so} that the resin solid content was 0.8 g / m ^2. After coating (50 m / min, 11 kg / cm, 6% aqueous solution), drying was performed at 105 ° C. for 2 minutes with a cylindrical rotary dryer, and finishing was performed with a super calender to obtain a sizing paper. The obtained sizing paper was evaluated for rewetting adhesion, tenacity, surface paper strength, and sizing degree in the following manner.

(Rewet Adhesion Property) The following procedure was carried out in accordance with J.TAPPI No. 19 “Testing method for delamination strength of paperboard”.
The felt surfaces of the obtained sizing paper (100 mm × 100 mm) are overlapped with each other, immersed in water for 5 minutes, and then sandwiched between filter papers and pressed through a calender roll at a pressure of 100 kg / cm. Next, after adjusting the humidity at 20 ° C. and 65% RH for 24 hours, a tensile tester (“Tensilon UTM-2-20” manufactured by Toyo Baldwin,
Adhesive force (g / 3) by pulling speed: 200 mm / min)
0 mm). (Tappability) One-color double-sided printing was continuously performed on sizing paper using an offset rotary printing press, and evaluated as follows. ○ −−− Continuous printing of 10,000m or more is possible △ −−− Adhesion of the sizing agent to the rotary printing press (roll) was recognized from 5000m × −−− From 2000m to the rotary printing press (roll) Adhesion was observed, leading to paper breakage

(Surface strength of surface paper) Fine ink TV was applied to the ink using an IGT printing tester (manufactured by Kumagai Riki Co., Ltd.).
-20 (manufactured by Dainippon Ink and Chemicals, Inc.)
The T-pick strength (cm / sec) was measured. (Sizing degree) According to JIS P8122, the measurement of the Stekigt sizing degree (second) was performed.

Examples 2 to 9 The same evaluation as in Example 1 was carried out using a polyvinyl alcohol resin (A) and a ketene dimer (B) as shown in Table 1 (containing a carboxyl group). In addition, in Example 9, it carried out similarly to Example 1 except not having added maleic acid at the time of manufacture of a polyvinyl alcohol type resin.

Comparative Example 1 The procedure of Example 1 was repeated except that no ketene dimer (B) was added, and the same evaluation was performed. Comparative Example 2 A straight polyvinyl chloride paste resin was used in place of the ketene dimer (B) in Example 1, and the same evaluation was performed. Table 2 shows the evaluation results of the examples and the comparative examples.

[0024]

Table 1 Polyvinyl alcohol-based resin (A) Ketene dimer (B) Carboxyl group content (mol%) Content (parts) Type Content (parts) Example 1 0.5 100 Octadecyl ketene dimer 3.4% 2 1.0 100 〃 3.4 ヘ 3 0.5 100 Heptate silketene dimer 3.4 ４ 40.5 100 Octatetschilketen dimer 6.8 ５ 500 100 ４ 3.4 Comparative example 1 0.5 100 Zu 20.5 100 PVC * 3.4 Abbreviations are as follows * PVC: Straight polyvinyl chloride paste resin

[0025]

[Table 2] Rewet adhesion Adhesiveness Surface paper strength Strength Degree (g / 30mm) (cm / sec) (sec) Example 1 3.2 ２５０ 250 3.6 〃 2 1.8 ２６０ 260 8 ３ 3 2.6 210 4.5 ４ 4 1.5 ○ 200 4.2 ５ 5 1.6 ２ 270 2.8 Comparative Example 1 5.9 × 280 4.7 〃 2 4.7 × 250 3 .9

[0026]

The paper sizing agent composition of the present invention contains a polyvinyl alcohol resin (A) and a ketene dimer (B). It is excellent in workability and can improve the size and strength of paper, such as paperboard such as manila ball, white ball, liner paper, general high quality paper, medium quality paper, (lightweight) coated paper,
It can be suitably used for printing paper such as wrapping paper and gravure paper, upper / middle / lower grade paper, newsprint and the like.

Claims (5)

[Claims] 1. A paper sizing agent composition comprising a polyvinyl alcohol resin (A) and a ketene dimer (B). 2. The paper sizing composition according to claim 1, wherein the polyvinyl alcohol resin (A) is a carboxyl group-containing polyvinyl alcohol resin. 3. The paper sizing composition according to claim 1, wherein the content of the carboxyl group in the carboxyl group-containing polyvinyl alcohol-based resin is 0.1 to 10 mol%. 4. The content of the ketene dimer (B) is 0.1 to 100 parts by weight of the polyvinyl alcohol resin (A).
The sizing composition for paper according to any one of claims 1 to 3, wherein the amount is 1 to 50 parts by weight. 5. The paper sizing agent composition according to claim 1, wherein the polyvinyl alcohol resin (A) has an average degree of polymerization of 100 to 10,000.