JPH03227489A - Additive for paper-making process - Google Patents

Abstract

PURPOSE:To obtain the subject additive having remarkable paper-strengthening effect and exhibiting small variation of the effect in case of pH-variation of a paper-making system by polymerizing a vinyl monomer composed essential of (meth)acrylamide monomer in the presence of a water-soluble polymer. CONSTITUTION:The objective additive can be produced by polymerizing a vinyl monomer containing (meth)acrylamide monomer as essential component in the presence of a water-soluble polymer [preferably a polymer composed of (meth)acrylamide monomer, an anionic vinyl monomer, a cationic vinyl monomer and a nonionic vinyl monomer].

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper strength enhancer for paper. More specifically, the pH of pulp slurry during papermaking (hereinafter referred to as papermaking pH)
The present invention relates to a paper strength enhancer that exhibits small fluctuations in effectiveness against fluctuations in pulp slurry, and has a small decrease in effectiveness against dissolved components present in pulp slurry, such as inorganic salts such as sodium sulfate and calcium sulfate.

[Conventional technology]

Conventionally, anionic polyacrylamide (hereinafter referred to as PAM) has been the mainstream paper strength enhancer, but due to problems such as wastewater regulations, white water needs to be closed, or neutral paper is being made. The purpose is to further improve migration, resulting in poor fixation of the sizing agent, freeness, filler retention, etc., and 7=ionic PAM and amphoteric (cationic)
The method of use has changed to the combination system of PAM. The combination of anionic PAM and amphoteric (cationic) PAM improved drainage performance, filler and sizing agent fixing performance, paper strength effect, etc. In addition, recently, simultaneous addition formulations and mixed addition formulations of anionic PAM and amphoteric (cationic) PAM have been developed.
It is now possible to expect better drainage performance, sizing agent fixation, and paper strength effects. However, in terms of equipment, two lines are required, one for anions and one for amphoteric (cation). or,
It is known that whiteness, which is considered important in the paper field, is also significantly reduced. This is largely due to the aggregation of anionic PAM and amphoteric (cationic) PAM, which causes fine fibers that reduce whiteness (thickness) and dust in the white water system to be retained in the paper. In some cases, the strength of the cohesive force causes problems with deterioration of the paper's texture.

Recently, quaternary ammonium obtained by breeding vinyl monomers having a tertiary amino group or their salts with inorganic acids, or by reacting the vinyl monomer having a tertiary amine group with a quaternizing agent. Paper strength agents produced primarily from salt cationic vinyl monomers and acrylamide are beginning to be widely used. These paper strength enhancers are generally used alone, and when used alone, they have a relatively wide effective paper making pi (area), which improves paper strength, sizing agent fixing effect, filler retention effect, and whiteness reduction. However, in terms of strength, the anionic P
At present, this is not as satisfactory as compared to systems using a combination of AM and amphoteric (cationic) PAM.

[Problem to be solved by the invention]

The present invention uses a papermaking additive that has a high paper strength effect (and also has a small change in paper strength effect with respect to changes in papermaking pH, and a small change in paper strength effect with respect to dissolved components present in the pulp slurry). This is what we provide.

[Means to solve the problem]

The present inventors have completed the present invention as a result of intensive research to solve this problem.

That is, the invention is as follows.

1) A papermaking additive characterized by polymerizing a vinyl monomer containing (meth)acrylamide monomer as an essential component in the presence of a water-soluble polymer.

2) A patent claim in which the water-soluble polymer is a copolymer consisting of a reactive vinyl monomer as an essential component and one or more of the following monomers (A) to (0): The composition according to item 1.

(A) (meth)acrylamide monomer (B) Anionic vinyl monomer (C) Cationic vinyl monomer (D) Nonionic vinyl monomer [1 unit 3) Polymerizes in the presence of a water-soluble polymer The vinyl monomer is homopolymerized with a (meth)acrylamide monomer, or the (meth)acrylamide monomer and the following (E) to (G
2. The composition according to claim 1, which is a copolymer with one or more monomers selected from the following.

(E) Anionic vinyl monomer (F) Cationic vinyl monomer (G) Nonionic vinyl monomer 1iK 4) Solid content based on water-soluble polymer converts (meth)acrylamide monomer in its presence. The composition according to claim 1, wherein the composition is 3 wt% to 60 wt% based on the total solid content of the final product obtained by polymerizing the vinyl monomer as an essential component.

5) The reactive vinyl monomer component in the water-soluble polymer is 0.0
The composition according to claim 2, wherein I1 is 01% to 20 mol%.

6) The papermaking additive according to claim 1 is added in an amount of 0.03wt% to 3w based on the solid content of the papermaking pulp raw material.
A paper characterized in that the additive is added in a range of t%.

7) The papermaking additive according to claim 1 is added in an amount of 0.03wt% to 3w based on the solid content of the papermaking pulp raw material.
A method for producing paper, characterized in that the additive is added in a range of t%.

The present invention will be explained in more detail.

This papermaking additive is obtained by polymerizing a vinyl monomer containing (meth)acrylamide monomer as an essential component in the presence of a water-soluble polymer, and the preferred constituent units of this final product are: (meth)acrylamide monomer component is 5
0 to 97.9997 mol%, reactive vinyl monomer component is 0.0003*ol to 12■0! %, the anionic vinyl monomer component is 0 to 20%, the cationic vinyl monomer component is 2 to 50 mol%, and the nonionic vinyl monomer component is 0 to 30 mol%. Therefore, this structural unit may be freely composed of a water-soluble polymer and a vinyl monomer that polymerizes in the presence of the water-soluble polymer.

The reactive vinyl monomer component in the water-soluble polymer described in this patent is 0. The reason for O1 mol% to 20 mol% is 0.
If it is less than 1%, the paper strength enhancement effect is small, and 20
If it exceeds 1% g+o, an excessive crosslinking reaction will occur between the water-soluble polymer itself and the vinyl monomer whose essential component is (meth)acrylamide monomer in the presence of the water-soluble polymer, making it an additive for papermaking. This is because the agent will gel and become unusable.

The reactive vinyl monomers mentioned in this patent are monomers that support substituents that promote addition reactivity, such as N-alkoxymethyl (meth)acrylamide derivatives, glycidyl (meth)acrylate, 3-chloro -2-hydroxypropyl (meth)acrylate, acrolein, etc. can be mentioned. N-alkoxymethyl (meth)acrylamide derivatives include N-hydroxymethyl (meth)acrylamide, such as N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, N-n-butoxymethyl (meth)acrylamide, N
Examples include -tert, -butoxymethyl (meth)acrylamide, and the like.

Anionic vinyl monomers are, for example, unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, acrylic acid, crotonic acid, or citraconic acid, or their alkali metal salts such as sodium salts or potassium salts, or ammonium salts. Examples include salt and the like. Also,
For example, unsaturated sulfonic acids such as vinylsulfonic acid, allylsulfonic acid, methacrylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, or their sodium salts or Examples include alkali metal salts such as potassium salts, ammonium salts, and the like.

The cationic vinyl monomer is a vinyl monomer that grows an amino group or their organic or inorganic acid salts.

As substances that grow tertiary amine groups, for example, (meth)acrylic acid ester derivatives such as dialkylaminoethyl (meth)acrylate, dialkylaminopropyl (meth)acrylate, dialkylaminoethyl (meth)acrylate, etc.
Examples include (meth)acrylamide derivatives such as acrylamide, dialkylaminopropyl (meth)acrylamide, and (meth)acrylamide-3-methylbutyldimethylamine.

Examples of quaternary ammonium salts include quaternary ammonium salts obtained by reacting a vinyl monomer that grows a tertiary amine group with a quaternizing agent, and an alkyl halide as a quaternizing agent. , dialkyl sulfate, epichlorohydrin, benzyl halide, and the like. Further, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride and diallyldimethylammonium chloride can also be exemplified.

Nonionic vinyl monomers include unsaturated nitriles such as acrylonitrile and methachloronitrile, (meth)acrylic acid esters such as methyl (meth)acrylate, butyl (meth)acrylate, and hydroxyethyl (meth)acrylate, and methoxy (Meth)acrylamide compounds such as methyl (meth)acrylamide, butoxymethyl (meth)acrylamide, diacetone (meth)acrylamide, aromatic vinyl compounds such as styrene and methylstyrene, vinyl acetate, vinyl chloride, vinylidene chloride, N- Examples include vinylformamide.

In the presence of solids based on water-soluble polymers (meth)
It is 3 wt% to 60 wt%, preferably 5 wt% to 60 wt%, based on the total solid content of the final product obtained by polymerizing vinyl monomers containing acrylamide monomer as an essential component.
It is 50wt%. The reason why this range is necessary is 3wt%
If the amount is less than 60 wt%, the problem to be solved by the present invention cannot be solved, and if it exceeds 60 wt%, the polymerization yield will be low and the risk of gelation of the polymer will be very high. Because there is.

As a method for obtaining the coelectric delta body of the present invention, a known method used for the polymerization of this type of water-soluble vinyl monomer can be used.

For example, radical polymerization is preferred as the polymerization method. The monomer concentration is 2-3% by weight, preferably 5-30% by weight. The polymerization initiator is not particularly limited as long as it is water-soluble, and it is usually used after being dissolved in an aqueous monomer solution. Specifically, peroxides such as hydrogen peroxide and benzoyl peroxide,
persulfates such as sodium persulfate, potassium persulfate, ammonium persulfate; bromates such as sodium bromate, potassium bromate; perborates such as sodium perborate, potassium perborate, ammonium perborate; percarbonates such as sodium percarbonate, potassium percarbonate, ammonium percarbonate, superphosphates such as sodium perphosphate, potassium perphosphate, ammonium perphosphate, tert
, -butyl peroxide and the like. in this case,
Although it can be used alone, it can also be used as a redox polymerization agent in combination with a reducing agent. Examples of reducing agents include sulfites, bisulfites, salts of lower ionization such as iron, copper, and cobalt, breeding amines such as N, N, N', N''-tetramethylethylenediamine, and aldoses and ketoses. Examples include reducing sugars such as

In addition, as an azo compound, 2,2'-azobis-4-
Amidinopropane hydrochloride, 2,2'-azobis-2,4
-dimethylvaleronitrile, 4.4°-azobis-4-
Ciatsuvaleic acid and its salts, etc. can be used. Furthermore, it is also possible to use 2 g or more of the above-mentioned polymerization initiator.

Polymerization temperatures are lower (generally 3
The temperature is 0 to 90°C, and in the case of a redox polymerization initiator, it is lower, approximately 5 to 50°C. Further, during polymerization, it is not necessarily necessary to maintain the same temperature, and it may be changed as appropriate as the polymerization progresses, and the temperature is generally increased by the polymerization heat generated as the polymerization progresses. The atmosphere inside the polymerization vessel at this time is not particularly limited, but in order to speed up the polymerization, it is better to replace the atmosphere with an inert gas such as nitrogen gas. The polymerization time is not particularly limited, but is approximately 1 to 20 hours.

The molecular weight of the papermaking additive of the present invention is currently generally PAM
It may be the same as that used as a papermaking additive, and may have a weight average molecular weight of about 100,000 to 2,000,000.

The papermaking additive according to claim 1 is added in an amount of 0.03wt% to 3wt% based on the solid content of the papermaking pulp raw material.
It is added within the range of 0.1wt% to 2wt%, preferably 0.1wt% to 2wt%.
%. The reason why this range is necessary is that if it is less than 0.03 wt%, the effect of increasing paper strength is small and if it exceeds 3 wt%, it is uneconomical.

Any type of pulp can be used in making paper according to the invention. In addition to papermaking additives as paper strength enhancers such as those of the present invention, substances added to pulp generally include alumina polymers (aluminium sulfate, polyaluminum chloride, etc.), sizing agents, fillers, and yield. Although improvers and the like are often added, the present invention is not limited to these conditions.

[Effect]

According to the present invention, the paper-strength effect is high, and furthermore, the paper-strength effect has small fluctuations with respect to changes in papermaking pH, and the paper-strength effect has small fluctuations with respect to dissolved components present in the SLL slurry. were able to provide the drug. The reason for this is not necessarily clear, but while conventional PAM-based papermaking additives have a relatively linear structure, the PAM-based papermaking additive of the present invention has a partially branched or cross-linked structure. It is inferred that the number of structures and structures in which polymers envelop other polymers is increasing. Paper has a structure in which pulp fibers with a diameter of several microns to several tens of microns and a length of several hundred microns to several millimeters are intertwined. It is said that the improvement in the paper strength effect of PAM-based papermaking additives lies in the reinforcement of hydrogen bonds between pulp fibers. It is presumed that a three-dimensional structure is more suitable for reinforcing the hydrogen bonds than conventional PAM-based papermaking additives. It is assumed that they are connected.

In addition, it is said that electrical attractive force acts mainly on papermaking additives when they are fixed to pulp, and the PA of this patent
In addition to this effect, the M-based papermaking additive has the above-mentioned H4 structure that provides physical fixation to the pulp, so its effect changes little with changes in papermaking pH, and its presence in pulp slurry is small. It is surmised that this gives the dissolved components the property of having small effect fluctuations.

〔Example〕

The present invention will be specifically explained below with reference to Examples, but the present invention is not equally limited by these Examples.

In addition, all percentages and parts below are percentages by weight unless otherwise specified.
and parts by weight.

Example 1 In a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube, 180 parts of methacryloyl°oxyethyltrimethylammonium chloride, 20 parts of glycidyl methacrylate as a reactive vinyl monomer, and 750 parts of water were added.
I prepared a section. Thereafter, the internal temperature was raised to 30° C. while blowing nitrogen gas.

While stirring, a 10% aqueous ammonium persulfate solution and a 10% aqueous sodium bisulfite solution were added to initiate polymerization, which was maintained for 3 hours. Add the condensate to make the total volume 100
Brookfield viscosity at 25°C is 1
A 2-poise water-soluble polymer (A) was obtained.

150 of this water-soluble polymer (A) was placed in a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube.
1 part, 280 parts of 40% acrylamide, 10 parts of 80% acrylic acid, and 400 parts of water, and the pH was adjusted to 4.5 by adding 25% aqueous sodium hydroxide solution. Thereafter, the internal temperature was raised to 40° C. while blowing nitrogen gas. While stirring, add 10% ammonium persulfate aqueous solution and 10% ammonium persulfate solution.
% sodium bisulfite aqueous solution was added to start polymerization, and the polymerization was maintained for 3 hours. When the condensate was added to bring the total amount to 1000 parts, an aqueous solution with a Brookfield viscosity of 57 boids at 25° C. was obtained.

Example 2 225 parts of 80% acrylic acid, 20 parts of N-methylolacrylamide as a reactive vinyl monomer, and 450 parts of water were charged into a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction pipe. A 25% aqueous sodium hydroxide solution was added to adjust the pH to 4.5. Thereafter, the internal temperature was raised to 30° C. while blowing nitrogen gas. While stirring, 10% ammonium persulfate aqueous solution and 10% sodium bisulfite aqueous solution were added to start polymerization.
Holds time. When the condensate was added to bring the total amount to 1000 parts, a water-soluble polymer (B) having a Brookfield viscosity of 21 poise at 25°C was obtained.

Into a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 80 parts of this water-soluble polymer (B), 4
235 parts of 0% acrylamide, 40 parts of dimethylaminoethyl methacrylate, and 500 parts of water were charged, and a 20% aqueous sulfuric acid solution was added to adjust the pH to 4.5. Thereafter, the internal temperature was raised to 40° C. while blowing nitrogen gas. While stirring, add 10% ammonium persulfate aqueous solution and 10% ammonium persulfate solution.
% sodium bisulfite aqueous solution was added to start polymerization, and the polymerization was maintained for 3 hours. When the total amount was made up to 1000 parts by adding water, an aqueous solution having a Brookfield viscosity of 50 poise at 25° C. was obtained.

Example 3 385 parts of 40% acrylamide, 5 parts of dimethylaminopropylacrylamide, 20 parts of 80% acrylic acid, 20 parts of acrylonitrile, reactive 5 parts of N-methylolacrylamide and 50 parts of water as vinyl monomers
0 parts were added, and the pH was adjusted to 4.5 by adding 25% aqueous sodium hydroxide solution. Thereafter, the internal temperature was raised to 30° C. while blowing nitrogen gas. While stirring, 1
A 0% ammonium persulfate aqueous solution and a 10% sodium bisulfite aqueous solution were added to start polymerization, and the polymerization was maintained for 3 hours. When the total amount was made up to 1000 parts by adding water, a water-soluble polymer (C) having a Brookfield viscosity of 11 poise at 25° C. was obtained.

300 parts of this water-soluble polymer (C) was placed in a four-bottle flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen gas introduction tube.
175 parts of 40% acrylamide, 20 parts of dimethylaminoethyl methacrylate, and 400 parts of water were charged, and the pH was adjusted to 4.5 by adding a 20% aqueous sulfuric acid solution. Thereafter, the internal temperature was raised to 40° C. while blowing nitrogen gas. While stirring, add 10% ammonium persulfate aqueous solution and 1
Polymerization was started by adding 0% sodium bisulfite aqueous solution and maintained for 3 hours. Add that water to make the total amount 1000
Brookfield viscosity at 25°C is 61 parts.
An aqueous solution of poise was obtained.

Comparative Example 1 180 parts of methacryloyloxyethyltrimethylammonium chloride and 750 parts of water were charged into a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube. After that, while blowing nitrogen gas, the internal temperature was lowered to 30℃.
The temperature was raised to ℃. While stirring, a 10% aqueous ammonium persulfate solution and a 10% aqueous sodium bisulfite solution were added to initiate polymerization, which was maintained for 3 hours. When the total amount was made up to 1000 parts by adding water, a water-soluble polymer (D) having a Brookfield viscosity of 10 poise at 25° C. was obtained.

150 of this water-soluble polymer (D) was placed in a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube.
1 part, 280 parts of 40% acrylamide, 10 parts of 80% acrylic acid, and 400 parts of water, and the pH was adjusted to 4.5 by adding 25% aqueous sodium hydroxide solution. Thereafter, the internal temperature was raised to 40° C. while blowing nitrogen gas. While stirring, add 10% ammonium persulfate aqueous solution and 10% ammonium persulfate solution.
% sodium bisulfite aqueous solution was added to start polymerization, and the polymerization was maintained for 3 hours. When the total amount was made up to 1000 parts by adding water, an aqueous solution having a Brookfield viscosity of 51 poise at 25° C. was obtained. This is a comparative example in which no reactive monomer was used in Example 1.

Comparative Example 2 225 parts of 80% acrylic acid and 450 parts of water were placed in a four-bottle flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen gas introduction tube.
25% aqueous sodium hydroxide solution and p
Adjusted to H4.5. Thereafter, the internal temperature was raised to 30° C. while blowing nitrogen gas.

While stirring, a 10% aqueous ammonium persulfate solution and a 10% aqueous sodium bisulfite solution were added to initiate polymerization, which was maintained for 3 hours. Add the water and make the total amount 100
Brookfield viscosity at 25°C is 3 parts.
A water-soluble polymer (E) with zero voids was obtained.

Into a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 80 parts of this water-soluble polymer (E), 4
235 parts of 0% acrylamide, 40 parts of dimethylaminoethyl methacrylate, and 500 parts of water were charged, and the pH was adjusted to 4.5 by adding a 20% aqueous sulfuric acid solution. Thereafter, the internal temperature was raised to 40° C. while blowing nitrogen gas. While stirring, add 10% ammonium persulfate aqueous solution and 1
Polymerization was started by adding 0% sodium bisulfite aqueous solution and maintained for 3 hours. Add that water to make the total amount 1000
Brookfield viscosity at 25°C is 45 parts.
An aqueous solution of poise was obtained. This is a comparative example in which no reactive monomer was used in Example 2.

Comparative Example 3 385 parts of 40% acrylamide, 5 parts of dimethylaminopropylacrylamide, 20 parts of 80% acrylic acid, 20 parts of acrylonitrile, and 500 parts of water were placed in a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube. and add 25% sodium hydroxide aqueous solution to pH 4,
Adjusted to 5. Thereafter, the internal temperature was raised to 30° C. while blowing nitrogen gas.

While stirring, a 10% aqueous ammonium persulfate solution and a 10% aqueous sodium bisulfite solution were added to initiate polymerization, which was maintained for 3 hours. Add the condensate to make the total volume 100
When it is set as 0 parts, Brookfield viscosity at 25°C is 2.
A water-soluble polymer (F) of Ipoise was obtained.

Into a four-bottle flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen gas introduction tube, 300 parts of this water-soluble polymer (F),
175 parts of 40% acrylamide, 20 parts of dimethylaminoethyl methacrylate, and 400 parts of water were charged, and the pH was adjusted to 4.5 by adding a 20% aqueous sulfuric acid solution. Thereafter, the internal temperature was raised to 40° C. while blowing nitrogen gas. While stirring, add 10% ammonium persulfate aqueous solution and 1
Polymerization was started by adding 0% sodium bisulfite aqueous solution and maintained for 3 hours. Add the condensate to make the total amount 1000
Brookfield viscosity at 25°C is 56 parts.
An aqueous solution of poise was obtained. This is a comparative example in which no reactive monomer was used in Example 3.

Comparative Example 4 27 parts of methacryloyloxyethyltrimethylammonium chloride, 280 parts of 40% acrylamide, 10 parts of 80% acrylic acid, and 400 parts of water were placed in a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube. , add 25% sodium hydroxide aqueous solution to pH 4,
Adjusted to 5. Thereafter, the internal temperature was raised to 40° C. while blowing nitrogen gas. While stirring, a 10% aqueous ammonium persulfate solution and a 10% aqueous sodium bisulfite solution were added to initiate polymerization, which was maintained for 3 hours. When the condensate was added to bring the total amount to 1000 parts, an aqueous solution having a Brookfield viscosity of 54 poise at 25° C. was obtained. The water-soluble polymer using the reactive vinyl monomer in Example 1 was not present, and the other vinyl monomer components excluding the reactive vinyl monomer were mixed in bulk so that they had the same composition as in Example 1. This is a comparative example when polymerization was performed.

Application Example 1 A sulfuric acid band was added to a 1% pulp slurry of corrugated waste paper beaten in ClC3F45O to adjust the pH to three levels. 0 sulfuric acid band to the pulp of 1% pulp slurry
．． When 5%, 1%, and 2% were added, the pH values were 6.5, 5.6, and 4.7, respectively.

The papermaking additives produced in Examples 1 to 3 and the papermaking additives produced in Comparative Examples 1 to 4 were added to each of these 1% pulp slurries so that the solid content was 0.5% based on the pulp. did. These pulp slurries were made into paper with a basis weight of 150 g / / using a Tarapy standard sheet machine, and the bursting strength was measured according to JIS-P8112, and the biaxial strength was measured using an internal bond tester manufactured by Kumagai Riki Kogyo Co., Ltd. . The results are shown in Tables 1-1 and 1-2. Note that blank indicates that no papermaking additives were added.

Application Example 2 Sulfuric acid was added to a 1% pulp slurry of corrugated waste paper beaten to 160ml of C8F to adjust the pH to 6.5.

Add 0.0% sodium sulfate to this 1% pulp slurry.
2000.1% of each when added 4000ppm
The electrical conductivity of pulp slurry is 0°! 5.2.70.5
．． It became 21m5/c■. The papermaking additives produced in Examples 1 to 3 and the papermaking additives produced in Comparative Examples 1 to 4 were added to each of these 1% pulp slurries so that the solid content was 0.5% based on the pulp. did. These pulp slurries are processed into tsubo IL by Tarapee standard sheet machine.
A paper of 150 g/m was made, and the bursting strength was measured according to JIS-P8112, and the compressive strength was measured according to JIS-P8126.

The results are shown in Table 2-1 and Table 2-2. Note that blank indicates that no papermaking additives were added.

Application Example 3 A 1% pulp slurry of corrugated waste paper beaten to 160ml of C8F was adjusted to pH 6.6 by adding sulfuric acid bandate.

To this 1% pulp slurry, 01100.200 pp. of sodium lignin sulfonate was added. The papermaking additives produced in Examples 1 to 3 and the papermaking additives produced in Comparative Examples 1 to 4 were added to each of these 1% pulp slurries so that the solid content was 0.5% based on the pulp. did. These 1% pulp slurries were made into paper sheets with a weight of 11,150 g// by using a Tarapee standard sheet machine, and JIS
- Bursting strength was measured according to P8112, and compressive strength was measured according to JIS-P8126. The results are shown in Table 3-1 and Table 3-
Shown in 2. Note that blank indicates that no papermaking additives were added.

Table 1 = 1 - Table 1-2 Table 2-1 Table 2-2 Table 3-1 Table 3-2 [Effects of the invention] According to the present invention, the paper strength effect is high (and is also resistant to fluctuations in papermaking pH). It is possible to obtain a paper strength enhancer with small fluctuations in effectiveness (also with small fluctuations in effectiveness with respect to dissolved components present in the pulp slurry).

That is, when the papermaking pH changes as shown in Application Example 1,
Compared to the papermaking additives of Comparative Examples 1 to 4, which are not of the present invention, the papermaking additives of Examples 1 to 3 of the present invention have a high paper strength effect (and a small fluctuation in the paper strength effect).

In addition, as shown in Application Example 2, depending on the amount of sodium sulfate, which is a typical inorganic salt present in pulp slurry, the implementation of the present invention may be different from the papermaking additives of Comparative Examples 1 to 4, which are not the present invention. The papermaking additives of Examples 1 to 3 have high paper strength effects and small fluctuations in paper strength effects.

Furthermore, as shown in Application Example 3, by changing the amount of sodium ligninsulfonate as an example of an organic substance in the pulp slurry, the Example of the present invention was compared to the papermaking additives of Comparative Examples 1 to 4, which were not of the present invention. The papermaking additives 1 to 3 have a high paper strength effect and a small fluctuation in paper strength effect.

As described above, the papermaking additive of the present invention has a high paper strength effect,
In addition, it is clear that the material is highly resistant to fluctuations in the so-called paper-making conditions due to fluctuations in paper-making pH and fluctuations in the amount of various dissolved components in the pulp slurry, and the significance of the present invention is that big.

Claims (1)

[Scope of Claims] 1) A papermaking additive characterized by polymerizing a vinyl monomer containing (meth)acrylamide monomer as an essential component in the presence of a water-soluble polymer. 2) The water-soluble polymer is a copolymer consisting of a reactive vinyl monomer as an essential component and one or more of the following monomers (A) to (D). A composition according to scope 1. (A) (meth)acrylamide monomer (B) anionic vinyl monomer (C) cationic vinyl monomer (D) nonionic vinyl monomer 3) Vinyl that polymerizes in the presence of a water-soluble polymer The system monomer is homopolymerized with (meth)acrylamide monomer, or (
meth)acrylamide monomer and the following (E) to (G)
The composition according to claim 1, which is a copolymer with one or more monomers selected from the following. (E) Anionic vinyl monomer (F) Cationic vinyl monomer (G) Nonionic vinyl monomer 4) The solid content based on the water-soluble polymer becomes (meth)acrylamide monomer in its presence. The composition according to claim 1, wherein the composition is 3 wt% to 60 wt% based on the total solid content of the final product obtained by polymerizing a vinyl monomer having as an essential component. 5) The reactive vinyl monomer component in the water-soluble polymer is 0.0
The composition according to claim 2, which has a content of 1 mol% to 20 mol%. 6) The papermaking additive according to claim 1 is added in an amount of 0.03wt% to 3w based on the solid content of the papermaking pulp raw material.
A paper characterized in that the additive is added in a range of t%. 7) The papermaking additive according to claim 1 is added in an amount of 0.03wt% to 3w based on the solid content of the papermaking pulp raw material.
A method for producing paper, characterized in that the additive is added in a range of t%.