JPH11323780A - Composition for paper conversion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition for paper conversion, capable of imparting excellent barrier properties against air and oils to the paper after coating by compounding a specific phosphoric acid ester compound (salt) with a carboxy- containing polyvinyl alcoholic resin providing a specific aqueous solution viscosity. SOLUTION: This composition for paper conversion is obtained by compounding 0.1-30 pts.wt. phosphoric acid ester of the formula [R is H or an alkyl(allyl); (m) and (n) are each an integer; R' is H or an alkoxy], or its ethanolamine salt or ammonium salt, with 100 pts.wt. polyvinyl alcoholic resin. The polyvinyl alcoholic resin is obtained by saponifying a copolymer composed of a monoester of an ethylenically unsaturated carboxylic acid, such as a monoester of maleic acid, with a vinyl ester-based compound such as vinyl acetate, provides a 10 wt.% aqueous solution having 1-40 mPa.s viscosity at 40 deg.C at 2.5×10<5> sec<-1> shear rate, and contains 0.1-10 mol.% carboxy group. Paper is preferably coated with the composition so that the amount of the modified polyvinyl alcoholic resin expressed in terms of the solid may be 0.1-10 g/m<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a paper processing composition, and more particularly to a paper processing composition having excellent barrier properties, paper strength, and coating properties, and in particular, that the coated paper does not allow air and oils to pass through. The present invention relates to a paper processing composition having remarkably excellent barrier properties.

[0002]

2. Description of the Related Art Conventionally, vinyl ester resins, especially polyvinyl alcohol resins, have been used to improve the paper surface properties such as surface strength, smoothness, gloss and tackiness. Agent). The present applicant has also proposed a paper coating composition (JP-B-52-39442) containing a modified polyvinyl alcohol having a lactone ring in the molecule as a main component. On the other hand, an isocyanate compound is blended into a polyvinyl alcohol-based resin (Japanese Patent Publication No. 51-16080), or a polyvinyl alcohol-based resin is reacted with polyethyleneimine (Japanese Patent Laid-Open No. 9-208786).
Publication).

[0003]

However, in the technology disclosed in Japanese Patent Publication No. 52-39442, the barrier properties of the paper were secured at that time, but it is hardly sufficient for the recent new requirements. Also, Japanese Patent Publication No. 52-3
In the technology disclosed in Japanese Patent No. 9442, there is a possibility that the water resistance and the solvent resistance may decrease over time.
In the technology disclosed in Japanese Patent Application Publication No. 6 (1999) -1995, it is expected that the reactivity of the polyvinyl alcohol-based resin and polyethyleneimine changes depending on conditions such as pH, and that the properties cannot be sufficiently exhibited. There is a demand for a paper processing agent which is remarkably excellent in properties, paper strength, coatability, and particularly, a barrier property that does not allow air or oil to pass through the coated paper.

[0004]

[Means to solve the problem] Therefore, the present inventors,
In view of such circumstances, as a result of intensive studies, a carboxyl group-containing polyvinyl alcohol-based resin having a 10% by weight aqueous solution viscosity of ^{1 to} 40 mPa · s at a shear rate of 2.5 × 10 ⁵ sec ^{−1 at} 40 ° C. and the following: The paper processing composition containing the phosphate compound represented by the general formula (1) or a salt thereof has a barrier property, a paper strength,
The inventors have found that the coating properties, particularly the barrier properties of the coated paper, which does not allow the passage of air and oils, are remarkably excellent, and have completed the present invention.

Embedded image (However, R represents any one of hydrogen, an alkyl group and an alkyl allyl group, m and n are integers, and R ′ represents hydrogen or an alkoxy group, respectively.)

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below.
The carboxyl group-containing polyvinyl alcohol resin used in the present invention has a viscosity of 1 to 40 at a shear rate of 2.5 × 10 ⁵ sec ^{-1 at} 40 ° C. of a 10% by weight aqueous solution thereof.
If it is mPa · s, the production is not particularly limited, for example, a method of obtaining a copolymer from an unsaturated monomer having a carboxyl group and a vinyl ester-based compound, then saponifying the copolymer, A method in which a monomer having an oxyalkylene group is graft-polymerized to a polyvinyl alcohol-based resin having a carboxyl group may be mentioned, but the method is practical in terms of resin production and performance.

Hereinafter, the following method will be described in detail. Examples of unsaturated monomers having a carboxyl group include ethylenically unsaturated dicarboxylic acids (maleic acid, fumaric acid,
Itaconic acid), or an ethylenically unsaturated carboxylic acid monoester (monoalkyl maleate, monoalkyl fumarate, monoalkyl itaconate), or an ethylenically unsaturated dicarboxylic acid diester (dialkyl maleate, dialkyl fumarate) Esters, dialkyl itaconates), monomers such as ethylenically unsaturated carboxylic anhydrides (maleic anhydride, itaconic anhydride), or (meth) acrylic acid, and salts thereof. Saturated carboxylic acid monoesters or salts thereof are preferably used.

[0007] The vinyl ester compounds include:
Vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caprate, vinyl laurate, vinyl versatate, vinyl palmitate, vinyl stearate, etc. can be used alone or in combination, but vinyl acetate is particularly practical. High in nature.

In the present invention, in addition to the above-mentioned monomer having a carboxyl group and a vinyl ester compound during polymerization, allyl esters of saturated carboxylic acids (allyl stearate, allyl laurate, allyl coconut fatty acid) , Allyl octylate, allyl butyrate, etc.), α-olefins (ethylene, propylene, α-hexene, α-octene, α-decene, α-dodecene, α-hexadecene,
α-octadecene, etc.), 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, etc.), 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, etc.), furthermore, (meth) acrylamide, (meth) acrylonitrile, (meth) Allyl sulfonate, ethylenically unsaturated sulfonate, styrene, vinyl chloride, etc. (Vinyl ester) a monomer which can be copolymerized may be performed polymerization allowed to exist than 50 mol%. There is no particular limitation on the copolymerization, and any known polymerization method may be used, but solution polymerization is usually performed using an alcohol such as methanol or ethanol as a solvent.

In such a method, as a method of charging the monomers, first, the total amount of the vinyl ester compound and a part of the carboxyl group-containing unsaturated monomer are charged and polymerization is started, and the remaining unsaturated monomer is charged. Arbitrary means such as a method of adding continuously or dividedly during the polymerization period and a method of batch charging 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. In the saponification, the copolymer is dissolved in an alcohol, an acetic ester or a mixed solvent thereof, and is carried out in the presence of an alkali catalyst. Examples of the alcohol include methanol, ethanol, and butanol, and examples of the acetate include methyl acetate and ethyl acetate. The concentration of the copolymer in the alcohol is 20 to
It is selected from the range of 50% 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 40 ° C. The reaction is usually carried out for 2 to 3 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 resin is obtained. The content of the carboxyl group is preferably 0.1 to 10 mol%.
Further, when the content of the carboxyl group is less than 0.1 mol%, the paper strength is low,
If the amount exceeds mol%, the solubility when used as a processing agent (coating liquid) becomes poor, which is not preferable.

In the present invention, the viscosity of a 10% by weight aqueous solution of the above-mentioned carboxyl group-containing polyvinyl alcohol resin at a shear rate of 2.5 × 10 ⁵ sec ^-1 at 40 ° C. is ^{1 to} 40 mPa · s (and 5 ~ 30mPa ・
s), and the viscosity of the aqueous solution is 1 mPa
If it is less than s, the paper strength is reduced and the printability is poor, and if it exceeds 40 mPa · s, on the other hand, the coatability when used as a processing agent (coating liquid) is reduced or coating unevenness occurs.

The phosphate compound or a salt thereof mixed with the above-mentioned carboxyl group-containing polyvinyl alcohol resin is a compound represented by the following general formula (1) or a salt thereof. Salts, sodium salts, potassium salts and the like can be mentioned, and ethanolamine salts and ammonium salts are preferably used.

Embedded image (However, R represents any one of hydrogen, an alkyl group and an alkyl allyl group, m and n are integers, and R ′ represents hydrogen or an alkoxy group, respectively.)

The paper processing composition of the present invention comprises a carboxyl group-containing polyvinyl alcohol resin as described above and a phosphate compound represented by the above general formula (1) or a salt thereof. The mixing ratio is preferably from 0.1 to 30 parts by weight, more preferably from 1 to 20 parts by weight, more preferably from 0.1 to 30 parts by weight of the phosphoric ester compound or a salt thereof, based on 100 parts by weight of the carboxyl group-containing polyvinyl alcohol resin. When the amount is less than 0.1 part by weight, the effect of the compounding is poor, and when the amount exceeds 30 parts by weight, the paper strength decreases.
Further, unevenness is generated during coating, which is not preferable.

The thus obtained paper processing composition of the present invention is generally used by dissolving it in water, but it can also be used in a solvent system. The type of the solvent may be appropriately selected depending on the characteristics of the carboxyl group-containing polyvinyl alcohol-based resin, the mixing ratio of the carboxyl group-containing polyvinyl alcohol-based resin and the phosphate compound or its salt, and the like. 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.

The paper processing composition of the present invention is used as a coating solution when used, and there is no particular limitation in the preparation of the coating solution. The phosphoric ester compound or a salt thereof may be mixed. The concentration may be appropriately adjusted depending on the purpose, and the concentration of a particularly preferable mixture of the carboxyl group-containing polyvinyl alcohol-based resin and the phosphate compound or its salt is usually 0.1 to 0.1 in consideration of workability and the like. 40% by weight, further 1-2
It is selected from a range of about 0% by weight.

The paper processing composition of the present invention contains a carboxyl group-containing polyvinyl alcohol-based resin and the phosphate compound or its salt as described above. If necessary, glyoxal, epichlorohydrin, carbonate Zirconium ammonium, tetra-n-
Water-proofing agents such as butyl titanate, tetra-n-isopropyl titanate, urea resin, etc., known additives such as defoaming agents, release agents, surfactants, preservatives, insect repellents, rust inhibitors, thickeners, etc. It can be added, and other paper processing agents such as other conventionally known resins such as polyvinyl alcohol, starch, carboxymethylcellulose, acrylic latex, and SBR latex can be mixed as long as the characteristics of the present invention are not impaired. can do.

The paper to be coated with the paper processing composition (coating liquid) of the present invention is not particularly limited. Examples thereof include thermosensitive recording paper, release paper, release paper, inkjet paper, carbon paper,
Non-carbon paper, base paper for paper cups, oil-resistant paper, paperboard such as manila balls, white balls, liners, etc., printing paper such as general high quality paper, medium quality paper, gravure paper, upper / middle / lower grade paper, newsprint etc. are suitable. Used for In applying the paper processing composition (coating liquid) to such a paper, any known method such as a size press coat, a roll coater method, an air yard method, a blade coater method, and a gate roll coater method is employed. Is done.

Thus, the coating amount of the paper processing composition is as follows:
The amount of the carboxyl group-containing polyvinyl alcohol-based resin is 0.
1 to 10 g / m ² (in terms of solid content), particularly preferably 0.1 g / m ² .
It is appropriate that the amount is about 5 to 5 g / m ² (same as above). Of course, the method is not limited to the above, and the so-called internal size method in which the paper processing composition of the present invention is dissolved in a pulp dispersion to make paper, or further powdery or fibrous paper processing composition of the present invention is used in paper. The paper processing composition of the present invention can be applied to paper by any method, such as mixing in paper.

The paper processing composition of the present invention is mainly used as a clear coating agent as described above.
It can also be suitably used as a binder for pigment coating, as pigments clay, calcium carbonate,
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 aggregates when the binder is added in a state where the pigment is dispersed), which has been a problem in the conventional pigment coating,
In addition, a very excellent effect is exhibited on the dispersibility of the pigment.

[0022]

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 a polyvinyl alcohol resin containing a carboxyl group] A polymerization vessel was charged with 500 parts of vinyl acetate and 3.4 parts of maleic acid.
And 85 parts of methanol (S / M = 0.17)
0), the temperature was raised in a nitrogen stream while stirring the system, and the temperature was increased to 3 at 60 ° C.
After refluxing for 0 minutes, azobisisobutyronitrile was added at 0.08 mol% to vinyl acetate, and a methanol solution of maleic acid was charged to carry out dropwise polymerization so that the degree of modification was 1.0 mol%. When the rate reached 70%, the reaction was terminated, and methanol vapor was blown to remove unreacted monomers to obtain a methanol solution of the copolymer. Next, the obtained methanol solution was diluted to 40% with methanol. Further, sodium hydroxide was added to the vinyl acetate in the copolymer at 40 mmol% to effect saponification. The resulting saponified product was filtered, dried at 70 ° C., and dried at a carboxyl group-containing polyvinyl alcohol resin (degree of saponification). 94.0 mol%)
I got Shear rate of the obtained carboxyl group-containing polyvinyl alcohol-based resin at 40 ° C. 2.5 × 10 ⁵ sec
^The viscosity of a 10% by weight aqueous solution at ^-1 was measured with a Hercules-type rotational viscometer (manufactured by Mitsui Electric Seiki Co., Ltd.).
It was 0 mPa · s.

6.00 parts of the above-mentioned carboxyl group-containing polyvinyl alcohol-based resin and 0.12 parts of the salt of the phosphoric ester compound shown in Table 2 were added to Table 2 with respect to 100 parts of the carboxyl-containing polyvinyl alcohol-based resin. (2 parts of a salt of the phosphoric acid ester compound) is dissolved in 93.88 parts of water to form a coating solution, and the coating solution is applied to an acidic paper having a basis weight of 60 g / m ^{2 in} a resin solid content of 2.0 g / m ^2. Size press coat (speed: 90m / min, linear pressure: 11k
g / cm) and then 10 with a cylindrical rotary dryer.
Dry at 5 ° C for 2 minutes, and further add a super calender (temperature:
80 ° C, linear pressure: 40kg / cm)
A coated paper was obtained. About the obtained coated paper, barrier properties (air permeability and oil absorption), surface paper strength,
The applicability was evaluated in the following manner.

(Barrier property) Air permeability According to JIS P 8117, a test piece was fixed to an Oken-type air permeability tester (manufactured by Asahi Seiko Co., Ltd.), and the time required for 100 ml of air to pass ( Seconds). Oil Absorption Based on JIS P 8130, the time (second) for oil to be absorbed from the surface of paper into the inside was measured using an oil absorption tester (manufactured by Kumagai Riki Co., Ltd.).

(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.

(Coating property) The gloss and coating spots on the surface of the coated paper were evaluated by visual observation as follows. ○ --- Good gloss and no coating spots. △ --- Good gloss but coating spots. × --- Less gloss and coating spots. Examples 2-5 and Comparative Example 1 ４4 In the same manner as in Example 1, the same evaluation was carried out using a carboxyl group-containing polyvinyl alcohol-based resin as shown in Tables 1 and 2 and a salt of the indicated phosphate compound.
Table 3 shows the evaluation results of the examples and the comparative examples.

[0028]

TABLE 1 Carboxyl group-containing polyvinyl alcohol-based resin Carboxyl group content (mol%) Aqueous solution viscosity (mPa · s) Content (parts) Example 1 1.0 (maleic acid-modified) 20 100 〃 2 2.0 ( 〃) 40 100 ３ 31.0 (〃) 20 100 ４ 4 2.0 (〃) 20 100 〃 5 1.0 (modified with itaconic acid) 20 100 Comparative Example 1 1.0 (modified with maleic acid) 20 100 〃 2 1.0 (〃) 60 100 ３ 3 1.0 (〃) 0.05 100 ４ 40 (native) 20 100

[0029]

[Table 2] *: In the above general formula (1), R = ethyl group, m =
2, n = 2, R '= ethanol of phosphate ester of ethoxy group
Nolamine salt: In the above general formula (1), R = methyl group, m = 3,
n = 2, R ′ = ammonium of ethoxy group phosphate ester
Um salt: In the above general formula (1), R = ethyl group, m = 3,
n = 2, R ′ = ammonium of ethoxy group phosphate ester
Note) The contents in Tables 1 and 2 include carboxyl groups
Phosphoric acid based on 100 parts of polyvinyl alcohol-based resin
It represents a salt of an ester compound.

[0030]

TABLE 3 barrier air permeability oil absorption surface paper strength strength coatability (sec) (sec) (cm / sec) Example 1 35 35 195 ○ 〃 2 90 90 400 ○ 〃 3 40 35 185 ○ 〃 4 45 40 180 〃 ５ 5 40 40 185 比較 Comparative Example 1 15 10 175 〃 〃 2 280 155 430 × ３ 3 20 10 165 × ４ 4 10 10 150 ×

[0031]

The paper processing composition of the present invention contains a carboxyl group-containing polyvinyl alcohol-based resin having a specific viscosity and a phosphate compound or a salt thereof, so that it has barrier properties, paper strength, and coatability. , Especially excellent in barrier property that the coated paper does not allow air and oils to pass through, thermal recording paper, release paper, release paper, inkjet paper, carbon paper, non-carbon paper, base paper for paper cups,
For paperboard such as oil-resistant paper, manila ball, white ball, liner paper, general high quality paper, medium quality paper, (lightweight) coated paper, packaging paper, printing paper such as gravure paper, upper / middle / lower grade paper, newsprint etc. It can be suitably used.

Claims (4)

[Claims] 1. A shear rate of 2.5 × 10 ⁵ sec at 40 ° C.
The viscosity of a 10% by weight aqueous solution at c ^-1 is ¹ to 40 mPa
-A paper processing composition comprising a carboxyl group-containing polyvinyl alcohol resin represented by s and a phosphate compound represented by the following general formula (1) or a salt thereof. Embedded image (However, R represents any one of hydrogen, an alkyl group and an alkyl allyl group, m and n are integers, and R ′ represents hydrogen or an alkoxy group, respectively.) 2. A phosphoric acid ester compound represented by the above general formula (1) or a salt thereof is added in an amount of 0.1 to 100 parts by weight of a carboxyl group-containing polyvinyl alcohol resin.
2. The paper processing composition according to claim 1, wherein the composition is 30 parts by weight. 3. The paper processing 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 paper processing composition according to claim 1, which is used for coating the surface of paper.