JPS5823995A - Dimension stabilizer of paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to dimensional stabilizers for paper.

The essential drawback of paper whose main component is cellulose is that it expands and contracts significantly when exposed to moisture, and improvement of this problem has become an important issue in the fields of printing, recording paper, and the like.

A lot of research has been done on the elasticity of paper due to moisture, but the type of pulp, degree of beating, dry size, and many other factors have a complex influence, so it is difficult to determine the safety of expansion and contraction. The reason for this is currently not clear.

Incidentally, conventionally proposed methods for stabilizing the dimensions of paper against moisture include, for example, converting the hydroxyl groups of cellulose into hydrophobic groups by chemically treating them; Paper is made by adding a hydrophobic substance such as polyacrylonitrile; the surface of the paper is coated with a hydrophobic substance; beating is moderated to reduce the entanglement of fibers; mineral filler is added; resin is added. Methods are known, such as binding fibers three-dimensionally to prevent drying or drying them in close contact on a large diameter cylinder, but these methods, for example, do not have sufficient dimensional stability effects. Or it has little effect or the strength of the paper is significantly reduced. They have advantages and disadvantages, such as inhibiting the flexibility of the paper, having an adverse effect on printing characteristics, and being less economical, and have moderate practical problems111.

Additionally, or as a separate problem, peel-off paper such as printing paper, information industry paper (computer cards, etc.) and label paper often suffers from curling due to the influence of moisture.

Troubles caused by the power of paper not only reduce efficiency in factory operations, but also affect yields and have no negative impact on profitability. many.

There are various causes for curling, such as paper being oriented and anisotropic due to mechanical cutting, and density differences between the front and back sides of the paper.

Curling can also occur when there is a difference in fiber arrangement between the front and back sides of the paper, when the filler distribution is different in the thickness direction, when the internal strain is different between the front and back sides, or when the coating agent is applied only to one side. This often occurs when plastic film or aluminum is peeled off.

A conventionally proposed method for preventing curling involves the addition of fillers such as clay and talc to minimize the difference in density between the front and back sides of the paper in the papermaking process in the Ring 8 paper process. In addition, if you apply a coating agent only to one side, coach the back side with water and dry it, add a moisturizer such as glycerin or polyethylene glycol, and a softener.
There are known methods for retaining an appropriate amount of moisture in paper and giving it flexibility, but in these methods, for example,
There are advantages and disadvantages, such as insufficient or almost ineffective anti-curling effect, abrasion resistance, decreased surface strength, adverse effects on printing characteristics, or poor economic efficiency, and there are some practical problems. are doing.

In view of the current situation, the present inventors have conducted various studies on methods for stabilizing the dimensions of paper and methods for preventing curling. The present inventors have discovered that a mixture of a specific water-soluble copolymer consisting of a water-soluble polyaldehyde, and polyacrylic acid has excellent effects as a dimensional stabilizer and anti-curl agent for paper, and have completed the present invention. Ta.

That is, in the present invention, R3 represents a hydrogen atom or a methyl group; R3 represents a hydrogen atom or a lower alkyl group, respectively. ] At least one acrylamide or methacrylamide monomer represented by the formula: CH, =C-COO÷Cm H2m O
h R4 [In the formula, R4 represents a hydrogen atom or a methyl group; R4 represents a hydrogen atom or a lower acyl group. m; integer from 2 to 4,
n: Represents an integer number from 2 to 50. ] and at least one polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate represented by IC) General formula CH2=C-C0NHCH20R, (wherein R1 is a hydrogen atom or a methyl group; R3 is a hydrogen atom or a lower alkyl group.] and D) at least one methylol acrylamide or methylol methacrylamide monomer represented by 1 to 12 in the alkyl group.
Alkyl esters of acrylic acid or methacrylic acid having 5 carbon atoms; general formula R.

Hydroxyalkyl esters of acrylic acid or methacrylic acid represented by CH2=C-COO-CH, CH- [in the formula, R8 is H hydrogen atom or methyl group; bird represents a hydrogen atom or a lower alkyl group]; or nitriles such as acrylonitrile and methacrylonitrile; or general formula R
1 CH2=C-C00B [: In the formula, R represents a hydrogen atom or a methyl group, B represents a hydrogen atom or an alkali metal salt, an ammonium salt, an amine salt, an alkanolamine salt] A polymer that requires a composition consisting of 10 to 90% by weight of (4), 5 to 40% by weight of (B), and 5 to 30% by weight of (C) and 0 to 30% by weight of (D). The object of the present invention is to provide a two-component curing paper dimensional stabilizer and paper anti-curl agent comprising a water-soluble polyaldehyde containing a polymer and polyacrylic acid.

The present invention will be explained in more detail below.

Examples of the acrylamide or methacrylamide monomer A) of the coelectric polymer component of the paper dimensional stabilizer and anti-curling agent of the present invention include acrylamide and methacrylamide (hereinafter collectively referred to as acrylic or methacrylic).
It is called methacrylic. )N,N-dimethyl-(meth)
Acrylamide, N,N-diethyl-(meth)acrylamide N.

N-gen or -propyl-(meth)acrylamide, etc., and preferably acrylamide and methacrylamide are used. 1 General formula for B) CH2=C-Coo÷cm R2m O
h ”'4 [In the formula, R1 is a hydrogen atom or a methyl group, R4
represents a hydrogen atom or a lower alkyl group. However, □；2
An integer of ~4, n; represents an integer of 2 to 50. The polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate represented by ] is obtained by polymerizing ethylene oxide, propylene oxide, butylene oxide, or nitrahydrofuran alone or in combination with hydroxyalkyl monoacrylate or hydroxyalkyl monomethacrylate. It is also a compound in which the hydrogen atom in the terminal hydroxyl group is substituted with a methyl group, ethyl group, propyl group, or butyl group.

Specific examples of Kl/-1 include the following.

ω-hydroxy-poly(ethyleneoxy)-(meth)acrylate, ω-hydroxy-poly(propyleneoxy)-(meth)acrylate, ω-methoxy-poly(ethyleneoxy)-(meth)acrylate, ω-methoxy-
Poly(propyleneoxy)-(meth)acrylate is shown.

C) General formula CH22C-C0NHCH2oR5”[
: In the formula, R1 represents a hydrogen atom or a methyl group; R6 represents a hydrogen atom or a lower alkyl group. ] Preferred examples of the methylol acrylamide monomers represented by N-methylol acrylamide monomers include, for example, N-methylol-(meth)acrylamide, N-methoxytityl (meth)acrylamide,
N-ethoxymethyl-(meth)D) 1 in the alkyl group
Alkyl esters of sulfuric acid or methacrylic acid having ~12 carbon atoms, with the general formula cH,,=c-coo-cH2CH-R11C, where R1
■ cH is a hydrogen atom or a methyl group; the bird represents a hydrogen atom or a lower + alkyl group] Hydroxyalkyl esters of acrylic acid or methacrylic acid; or nitriles such as acrylonitrile and methacrylonitrile; or 1 General Formula CH,,=C-C00B In the formula, R1 is a hydrogen atom or a methyl group, B is a hydrogen atom or an alkali metal salt,
Preferred examples of ammonium salt, amine salt, alkanolamine salt are methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, tertiary-butyl acrylate, acrylic Acrylic acid esters such as 2-ethylhexyl acid, methyl methacrylate, ethyl methacrylate,
Preferred examples of methacrylic acid esters such as isopropyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, tertiary butyl methacrylate, and 2-ethylhexyl methacrylate, and hydroxyacrylate include hydroxyethyl-(methacrylate). ) Acrylate, nitriles such as 2-hydroxypropyl-(meth)acrylate, 2-hydroxybutyl-(meth)acrylate, acrylonitrile, methacrylonitrile,
etc. are shown.

Preferably, the carboxy group-containing monomer includes acrylic acid, methacrylic acid, etc., and sodium salts, potassium salts, ammonium salts, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, and ethanol. Examples include amine, jetanolamine, and triethanolamine.

As for the composition of each monomer in the water-soluble copolymer of the present invention, component (A) is 10 to 90% by weight, (131 is 5 to 4% by weight)
The preferable range is 0% by weight, 5 to 30% by weight of (C), and 0 to 30% by weight of (D).

Polyacrylic acid is present in a mixture of the acrylamide monomer of the present invention and a specific water-soluble polymer consisting of polyoxyalkylene (meth)acrylate and methylol (meth)acrylamide and other unsaturated vinyl monomers and a water-soluble polyaldehyde compound. It has been found that when this material is impregnated or applied onto paper and dried, it significantly improves dimensional stability and anti-curling properties.

The function of this polyacrylic acid is thought to be that it serves as a condensation dehydration catalyst for reactions between hydroxyl groups in cellulose and methylolacrylamide groups, reactions between hydroxyl groups in cellulose and glyoxal, and reactions between glyoxal and amide groups. .

The amount of polyacrylic acid used is from 0.1% to 50% by weight based on the total solid content of the water-soluble copolymer and water-soluble polyaldehyde, and from 1% to 30% by weight. % is a suitable range.

The molecular weight of the polyacrylic acid used in the present invention is 200
Although polyacrylic acids with a molecular weight as low as 0 to as high as 1,000,000 can be used, a preferable range is polyacrylic acid that has a relatively low molecular weight of 2,000 to 100,000.

The acrylic acid monomer and an aqueous initiator solution are added dropwise to polymerize at the boiling point. Polyacrylic acid made by boiling point polymerization is preferred.

The polyacrylic acid produced by the above method has a pH of 1, but it may be used after being neutralized with an alkali to a pH of 2 to 5.

The acrylamide copolymer, water-soluble polyaldehyde and polyacrylic acid of the present invention are used as a dimensional stabilizer for coating or impregnating paper in a sipe press or off-machine.

The amount of the acrylamide copolymer added is preferably 0.1 to 15% by weight based on the weight of the pulp.

The water-soluble polyaldehyde is acrylamide copolymer 1.
The weight ratio is preferably in the range of 0.1 parts by weight to 3 parts by weight. Dimensional stability is 1. below 0.1 part by weight. The anti-curl effect is low, and if 111 is added in excess of 3 parts by weight, the quality of the paper deteriorates.

It is also commonly used in the paper industry for coating or impregnating. A sizing agent, a paper strength enhancer, etc. can be used in combination as appropriate.

Although there are no particular restrictions on the production of the copolymer of the present invention,
Normally, adjustment is made by the following method, for example. However, of course, it may be manufactured by other methods.

That is, a persulfate or A redox system of this and amine or sulfite is added, and the reaction is carried out for about 0.5 to 5 hours at a temperature from room temperature to about 100°C.As the persulfate used as a catalyst, water-soluble salts such as sodium, Salts such as potassium and ammonium are preferred, and examples of amines include primary amines such as monoethanolamine, hexamethylenediamine, aniline, secondary amines such as jetanolamine and monomethylaniline, and triethanolamine. , dimethylaniline, pyridine, picoline, and other tertiary amines.

There is no particular restriction on the amount of catalyst used, but it is usually desirable to use persulfate in an amount of 01-5.0% by weight and amine in an amount of 0.5-30% by weight based on the monomer. Yes. Even if the polymerization temperature is started at room temperature, the temperature increases with the initiation of polymerization and usually reaches a final temperature of about 70°C.

When the reaction is started at a temperature of about 70 to 80°C, it is necessary to cool it.

The molecular weight of the copolymer in the present invention may be as low as 5,000, or as high as 2,000,000.

However, copolymers having a relatively low molecular weight in the range of 10,000 to 1,000,000 are more suitable for practical use.

Hereinafter, the dimensional stabilizer and anti-curl agent for paper of the present invention will be specifically explained in terms of copolymer production, dimensional stability, and anti-curl agent.

However, these are merely examples to facilitate understanding of the present invention, and it goes without saying that the present invention is not limited to these alone, and is not limited in any way by these.

In the following examples, 1' part'' means part by weight.

Synthesis example 1゜In a three-ring flask equipped with a thermometer and a nitrogen inlet tube, add 70 parts of acrylamide, 5 parts of methacrylamide, and a number average molecular weight of 3.
70 polyoxypropylene glycol monomethacrylate (NOF ■ product, Bremmer pplo00) 10
10 parts of methylol acrylamide, 5 parts of acrylonitrile, and 400 parts of ion-exchanged water, and after bubbling with nitrogen gas for 30 minutes to remove oxygen from the system, adjust the liquid temperature to 20°C to prepare a redox system. Initiators 10 parts of a 50% aqueous solution of jetatoluamine and 10 parts of a 20% aqueous solution of ammonium persulfate were added to start the reaction.

Polymerization was continued for 1 hour after reaching 63°C to obtain a 20% aqueous solution of the copolymer.

The viscosity of this copolymer at 20°C is 1. OO0cp
It was s.

Test Example 1゜Ion-exchanged water and glyoxal were added to the 50% aqueous solution of the water-soluble copolymer synthesized in Synthesis Examples 1 to 5 so that the solid content of the water-soluble copolymer and glyoxal was 3%,
and polyacrylic acid (35% aqueous solution 20%)
After adding a predetermined amount of cps) and stirring, the basis weight is 60J.
? No-size paper was impregnated with the solution, and after wiping off the excess liquid with absorbent paper, it was dried at 120° C. for 5 minutes. This paper had a dye of 3.5 h of polymer and 3.5 h of glyoxal to the paper.

This paper was used as a 50×400111111 sample piece and left in a constant temperature and humidity chamber (20° C., 65 cm) day and night, and the water immersion elongation and air expansion/contraction rate were measured. The water immersion elongation is measured at 20°C.
Soak it in water for 10 minutes.
) was measured. Also, the aerial elongation rate is 20
℃ and humidity of 33℃, and the humidity is 33℃.
% to 72%, and the elongation rate was measured after being left for 24 hours at 72 inches. Similarly, the shrinkage ratio is 2
Using 0° C. and 72% humidity as a reference, the humidity was varied from 72 inches to 33%, and the shrinkage rate was measured after being left at 33 inches for 24 hours.

The results are shown in Table ■.

*] The amount of polyacrylic acid added is the solid content of polyacrylic acid added to the solid content of polymer + glyoxal *2
The curl characteristic is the same as the paper of 10 crn square <1
A 0crn square polyethylene film was attached, and the width of the curled state was measured when the relative temperature was changed from 30 degrees to 70%, and expressed as the total change of 4 squares.

Patent applicant: Showa Denko Co., Ltd. Agent: Patent attorney Sei Kikuchi

Claims (1)

[Claims] R. 3 represents a hydrogen atom or a methyl group; R2 and R3 each represent a hydrogen atom or a lower alkyl group. ] with at least one acrylamide or methacrylamide monomer represented by
□ R4 [In the formula, R1 represents a hydrogen atom or a methyl group; R4 represents a hydrogen atom or a lower alkyl group. m: an integer of 2 to 4, n: an integer of 2 to 50, represented by a circle] and at least one of polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate, and IC) General formula CH2 =C-C0NHCH20R, [:
In the formula, R1 represents a hydrogen atom or a methyl group; R1 represents a hydrogen atom or a lower alkyl group. D) At least one methylol acrylamide or methylol methacrylamide monomer represented by D) 1 to 12 alkyl groups
Alkyl esters of acrylic acid or methacrylic acid having 5 carbon atoms have the general formula CR2=C-COO-CH2CH- [wherein R7 is water H, hydrogen atom or methyl group; R6 is hydrogen atom or lower alkyl hydroxyalkyl esters of acrylic acid or methacrylic acid; nitriles such as acrylonitrile and methacrylonitrile; or the general formula CH2=C-C00B where R1 is a hydrogen atom or a methyl group, and B is a represents a hydrogen atom or an alkali metal salt, an ammonium salt, an amine salt, an alkanolamine salt], wherein (A) is 10-90% by weight and (B) is 5-40% by weight. Weight bed (C1 power (
A two-component curing paper dimensional stabilizer consisting of a copolymer having a composition of 5-30% by weight and 0-30% by weight of (D) and a water-soluble polyaldehyde containing polyacrylic acid, and paper. Anti-curl agent.