JPH07102497A - Method for producing pva coating paper - Google Patents

Abstract

PURPOSE:To provide a method for producing paper free from the odor of acetic acid, when PVA is thermally dissolved in a high concentration, when a PVA aqueous solution is stored at a high temperature for a long period, or when the PVA is coated on paper in a large amount. CONSTITUTION:A method for producing paper free from the odor of acetic acid is characterized by adding 0.01-100 pts. of hydrotalcite to 100 pts. of PVA, when paper is coated with a PVA aqueous solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing paper, and more particularly to a method for producing paper with less odor.

[0002]

2. Description of the Related Art Conventionally, polyvinyl alcohol (hereinafter referred to as P
VA) may be used as a clear coating agent for improving surface properties such as improvement of surface strength, smoothness, gloss or barrier property of paper, and also in pigment coating. Widely used as a binder. In addition, PVA is widely known to have excellent film-forming properties and strength that cannot be followed by other sizing agents. In particular, PVA has a property of low absorption and permeability of air, oil or organic solvents, that is, a barrier. It is widely used as a PVA coating agent in the production of papers having negative properties, and the resulting barrier papers have undergone particularly significant development, centering on the use as base paper for release paper. However, in recent years, in order to obtain higher performance paper or to increase productivity, it is necessary to use a base paper having a low barrier property (for example, air permeability of 10 seconds) using pulp that does not increase the beating degree so much. The PVA coating of
As a result, the odor generated from the coated PVA, particularly the acetic acid odor, becomes a problem, and improvement has been desired.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
It is an object of the present invention to provide a method for producing a paper having less odor generated from PVA when the aqueous solution is applied.

[0004]

The present inventors have found that PVA on paper
As a result of diligent study on a method for producing paper with little odor generated from PVA when applying the aqueous solution of PVA1,
0.01 to 10 parts by weight of hydrotalcite
The inventors have found that the intended purpose can be achieved by using 0 parts by weight in combination, and have completed the present invention.
Hydrotalcite is a natural mineral that has the ability to exchange ions with anionic substances, and is known to exist stably even when it adsorbs chloride ions and other acidic substances and is heated. However, it is blended with PVA to form paper. It has not been known in the past that when coated, the acetic acid odor of coated paper is almost eliminated.

The PVA used in the present invention saponifies polyvinyl acetate obtained by polymerizing or copolymerizing vinyl acetate by a known polymerization method such as bulk, solution, suspension or emulsification. It is obtained by The degree of saponification of PVA in the present invention is preferably 60 to 100 mol%, more preferably 70 to 99.9 mol%, and 80 to
Even more preferred is 99.5 mol%. Saponification degree is 60 mol%
If it is lower, the water solubility of PVA tends to decrease. The degree of polymerization of PVA used in the present invention is preferably 100 or more, more preferably 150 or more, and even more preferably 200 or more. If the degree of polymerization of PVA used in the present invention is less than 100, PV
There is a tendency that improvement in physical properties of paper such as barrier property and surface strength, which is the purpose of A coating, is hardly obtained. The upper limit of the degree of polymerization of PVA is not particularly limited, but it is 3 in terms of production cost.
It is more preferably 0000 or less. Furthermore, the PVA used in the present invention may be a mixture of two or more different types of PVA. Here, the degree of polymerization of PVA is a viscosity average degree of polymerization determined by a usual method from the viscosity of an aqueous solution of the completely saponified product of PVA.

The PVA used in the present invention is another monomer.
It is also possible to copolymerize with, and it is also possible to use one in which the polymer terminal is modified by using a chain transfer agent. The ethylenic monomer copolymerizable with vinyl ester is not particularly limited as long as it is copolymerizable with vinyl ester,
For example, ethylene, propylene, n-butene, isobutene, α-olefins such as 1-hexadecene, (meth)
Acrylic acid, fumaric acid, itaconic acid, crotonic acid, maleic acid, maleic anhydride, and other carboxylic acid-containing monomers and salts thereof, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid n -Butyl, 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid 2
-Ethylhexyl, (meth) acrylic acid esters such as stearyl (meth) acrylate, dimethyl fumarate, dimethyl itaconic acid, dimethyl maleate, monomethyl maleate, esters such as methyl crotonate, methyl vinyl ether, ethyl vinyl ether, butyl Vinyl ethers, lauryl vinyl ether, stearyl vinyl ether and other vinyl ethers, sulfonic acid group-containing monomers such as vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid and salts thereof, ( (Meth) acrylamide,
N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, Nt-butoxy (meth) acrylamide, Nt-octyl (meth) acrylamide, N-vinylpyrrolidone-containing amide groups Monomers, amino group-containing monomers such as dimethylaminoethyl (meth) acrylamide, quaternary ammonium salt-containing monomers such as (meth) acrylamide-propyl-trimethylammonium chloride, vinylhydroxysilane,
(Meth) acrylic acid-3-trimethoxysilylpropyl and other silyl group-containing monomers, allyl alcohol, dimethylallyl alcohol, isopropenyl alcohol and other hydroxyl group-containing monomers, allyl acetate, Examples include acetyl group-containing monomers such as dimethylallyl acetate and isopropenyl acetate.

The hydrotalcite that can be used in the present invention is a mineral represented by the following general formula. [M ↓ (1-x) N ↓ x (OH) ↓ 2] ↑ (x +) [A ↓ (x / n)
mH ↓ 2O] ↑ (x-)

(Where M is a divalent metal ion, N is a trivalent metal ion, A is an anion such as a hydroxide ion, a halide ion, a carbonate ion, and a ferrician ion, and x is 0 <
It is a number in the range of x <0.35. n is the ionic valence of the anion A. ) Specific examples of M are not particularly limited as long as they are divalent metal ions, but are ions of magnesium, manganese, iron, cobalt, nickel, copper, zinc and the like. Of these, the most commonly contained hydrotalcite is magnesium ion. Specific examples of N are trivalent ions such as aluminum, iron, chromium, cobalt and indium. Generally, aluminum ions are often contained. Specific examples of A include hydroxyl ions, halogen ions of fluorine, chlorine and bromine, nitrate ions, carbonate ions, sulfate ions, ferrician ions, oxalate ions, acetate ions, etc., but are generated from PVA. Considering that it adsorbs acetic acid, it is preferably a weak acid ion rather than acetic acid, and carbonate ion is particularly preferable. Further, although hydrotalcite is usually used as it is, it is also possible to use hydrotalcite obtained by baking and desorbing water, carbonate, etc. present in the crystal structure. In addition, blends with other resins and hydrotalcite powders with a fatty acid adhering treated to improve dispersibility can also be used.

In the present invention, the mixing ratio of PVA and hydrotalcite (hereinafter referred to as parts by weight) is PVA1.
Hydrotalcite 0.01-100 with respect to 00 parts
Part, preferably 0.1 to 50 parts, more preferably 1 to
It is 30 copies. If the amount of hydrotalcite is less than 0.01 part with respect to 100 parts of PVA, free acetic acid is not sufficiently trapped, and if it exceeds 100 parts, the effect of acetic acid trapping is not further improved, which is not preferable because of cost increase. . The method of mixing PVA and hydrotalcite in the present invention is not particularly limited, and any method can be used,
For example, a method of mixing PVA and hydrotalcite in a powder state, or making hydrotalcite into an aqueous dispersion to form PV.
There are a method of spraying and adsorbing the powder A or pellets, a method of dispersing hydrotalcite in a PVA aqueous solution prepared in advance, and the like.

In the production of the paper of the present invention, the method of applying the aqueous solution of PVA to the paper is not particularly limited, and examples thereof include roll coater, size press, blade coater, air knife coater and rod coater. -Ter, etc. The liquid concentration at the time of coating for producing the paper of the present invention is 1% by weight or more and 60% by weight or less, preferably 2% by weight or more and 50% by weight or more.
It is less than or equal to% by weight, and even more preferably between 3% by weight and less than 40% by weight. The liquid temperature, the liquid viscosity, the coating amount and the paper to be coated at the time of coating for producing the paper of the present invention are not particularly limited, and the liquid temperature, the liquid viscosity and the coating that are usually used in paper coating are used. Any amount and amount of paper to be coated can achieve the object of the present invention to reduce odor. In the production of the paper of the present invention, hydrotalcite is 0.01 per 100 parts of PVA.
It is essential to mix and use 100 to 100 parts, but starch and CM in the coating liquid may be used as long as the effects of the present invention are not impaired.
C, an inorganic pigment, an organic pigment, an emulsion, a latex and other auxiliaries (antifoaming agent, antistatic agent, antifungal agent, etc.) may be added.

[0011]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the examples, "%" and "parts" are based on weight unless otherwise specified.

Example 1 100 parts of commercially available partially saponified PVA (Kuraray Poval 205) having a viscosity average degree of polymerization of 560 and a degree of saponification of 88 mol% and hydrotalcite (Mg ↓ (4.5) Al ↓ 2 (OH) ↓ (13))・ (CO ↓ 3 ・ 3.5
H ↓ 2 O, Kyowa Chemical Industry Co., Ltd., DHT-4A) 10 parts by powder blending, put this in distilled water at room temperature, raise the temperature to 95 ° C, and continue stirring at 95 ° C for 30 minutes. , PVA
Was completely dissolved to obtain an aqueous solution having a solid content concentration of 25%.
1 kg of this aqueous solution was put in a cleanly washed 2 liter capacity polyethylene bottle, sealed, left to stand at 60 ° C. for 3 days, and then opened to confirm the odor inside, and there was no acetic acid odor. Using this liquid at 60 ℃, basis weight 43.3g / m ↑ 2, thickness 6
1μm density 0.71g / cm ↑ 3 paper with a gate roll coater for testing (made by Kumagai Seiki Co., Ltd.) and a solid content of 4.0g / m ↑ 2 on one side, then a rotary dryer at 100 ℃. When the odor of the paper obtained after drying for 1 minute was confirmed, there was no acetic acid odor.

Example 2 100 parts of commercially available completely saponified PVA (Kuraray Poval 103) having a viscosity average polymerization degree of 350 and a saponification degree of 98.5 mol% and 5 parts of hydrotalcite (DHT-4A manufactured by Kyowa Chemical Industry Co., Ltd.) were powdered. The body was blended, a 31% aqueous solution was prepared in the same manner as in Example 1, and the solution was coated on paper, and the odor generated from the solution and the coated paper was evaluated. The results are shown in Table 1.

Example 3 100 parts of commercially available completely saponified PVA (Kuraray Poval 117) having a viscosity average degree of polymerization of 1720 and a saponification degree of 98.5 mol% and 1 part of hydrotalcite (DHT-4A manufactured by Kyowa Chemical Industry Co., Ltd.) were powdered. The body was blended, an 11% aqueous solution was prepared in the same manner as in Example 1, and the solution was coated on paper, and the odor generated from the solution and the coated paper was evaluated. The results are shown in Table 1.

Comparative Example 1 The PVA composition of Example 1 was dissolved in the same manner as in Example 1 except that PVA containing no hydrotalcite was used.
When the odor generated from the solution and the coated paper was evaluated, a strong acetic acid odor was obtained from both.

Comparative Example 2 Using only PVA of the PVA composition of Example 2 containing no hydrotalcite, it was dissolved in the same manner as in Example 2 and the odor generated from the solution and coated paper was evaluated.
There was a strong acetic acid odor from both.

Comparative Example 3 Using only PVA of the PVA composition of Example 3 containing no hydrotalcite, it was dissolved in the same manner as in Example 3 and the odor generated from the solution and coated paper was evaluated.
In each case, a clear odor of acetic acid was produced although it was weaker than Comparative Examples 1 and 2.

[0018]

[Table 1]

[0019]

The method for producing paper according to the present invention is a very simple method in which 0.01 to 100 parts of hydrotalcite is added to 100 parts of PVA when the aqueous solution of PVA is applied to the paper. Thus, it has an extremely high industrial value in that it can effectively prevent the acetic acid odor generated from PVA.

Claims (1)

[Claims] 1. Low odor, characterized by using 0.01 to 100 parts by weight of hydrotalcite for 100 parts by weight of polyvinyl alcohol when the paper is coated with an aqueous solution of polyvinyl alcohol. Paper manufacturing method.