JPH0411095A - Production of additive for paper making - Google Patents

Abstract

PURPOSE:To obtain the subject additive composed of a water soluble polymer, low in variation of performance due to variation of pH and having a high effect for improvement of paper strength by polymerizing (meth)acrylamide, a water soluble cationic monomer (salt) and a crosslinkable monomer in the presence of copper ion. CONSTITUTION:As the essential monomer components, (A) 50-99.49mol%, preferably 55-98.98mol% acrylamide and/or methacrylamide, (B) 0.5-20mol%, preferably 1-15mol% water soluble cationic monomer and/or its salt [e.g. dimethylaminoethyl (meth)acrylate] and (C) 0.01-1mol%, preferably 0.02-0.8mol% crosslinkable monomer [e.g. methylenebis(meth)acrylamide] are used. The above- mentioned monomer mixture is polymerized in the presence of (D) 0.01-3ppm copper ion based on the total weight thereof, thus obtaining the objective additive composed of a water soluble polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a papermaking additive. More specifically, the present invention provides a method for producing a papermaking additive that exhibits a high paper strength enhancement effect with little performance variation in response to variations in the pH of pulp slurry during papermaking (hereinafter referred to as papermaking pH). be.

[Prior Art] Various papermaking additives have been used in the papermaking process to improve the quality of paper. In particular, paper strength enhancers, which have the ability to improve the strength of paper, are particularly important chemicals that are indispensable in paper manufacturing.

Paper strength enhancers include starches such as oxidized starch, pregelatinized starch, cationized starch, and dialdehyde starch, epichlorohydrin-modified polyamide polyamines, urea formaldehyde resins, and acrylamide-based polymers whose main components are acrylamide (hereinafter referred to as acrylamide-based polymers). )
Among these, acrylamide-based polymers are most widely and commonly used because of their synthetic advantages, performance, and ease of use.

Paper strength agents made of acrylamide-based polymers known so far include anionic polyacrylamide, amphoteric polyacrylamide obtained by modification by Mannich reaction or Hoffmann reaction, or copolymerization of cationic monomers. There are cationic or amphoteric polyacrylamides obtained by this process.

When these paper strength enhancers made of acrylamide polymers are added to the valve slurry in the papermaking system, they not only have the effect of increasing paper strength, but also have the effect of improving drainage, improving the yield of fillers, etc., either alone or in combination. is simultaneously expressed by the use of However, due to deterioration of paper-making conditions in recent paper-making processes, such as an increase in the proportion of recycled paper used, an increase in the degree of closure of white water due to drainage regulations, etc., and a shift in paper-making pH to a neutral range, it is no longer necessary to use paper strength enhancers. The current situation is that it is becoming difficult to fully demonstrate the various capabilities that are currently available. Therefore, there is an extremely strong demand for the development of a paper strength enhancer that is highly effective against such deterioration of the raw material situation, the amount of contaminants in the papermaking system, and fluctuations in the pH of papermaking, and which exhibits small fluctuations in adhesive performance.

Cationic or amphoteric polyacrylamides obtained by copolymerizing cationic monomers are effective as acrylamide-based polymers that meet these requirements.
8207, Japanese Unexamined Patent Publication No. 261197, Japanese Patent Application No. 2-17997
It has been proposed that acrylamide-based polymers into which cross-linking monomers have been introduced, such as, are particularly effective.

These acrylamide-based polymers are designed to effectively spread in water and improve various properties by introducing a crosslinked structure into the polymer chain, but the manufacturing method, especially the polymerization method, is Ordinary redox polymerization systems in the form of a combination of persulfate and a reducing agent such as sodium bisulfite as agents, or
The use of these in combination with chain transfer agents such as isopropyl alcohol and allyl alcohol does not go beyond the technical scope of conventional direct polymers, and as a result, the performance of the resulting acrylamide polymer as a papermaking additive is improved. Of course, there were limits.

[Problems to be Solved by the Invention] The present invention has a high paper strength effect, and furthermore, the effect has a small variation with respect to changes in papermaking pH, and the effect has a small variation with respect to dissolved components present in the pulp slurry. With regard to providing an additive for paper manufacturing, the present invention provides a manufacturing method that improves various performances of an acrylamide polymer into which a crosslinking monomer has been introduced as an additive for paper manufacturing.

[Means for Solving the Problems] The present inventors have conducted intensive studies with the aim of improving the various performances of an acrylamide-based polymer into which a crosslinking monomer has been introduced as a papermaking additive, and as a result, have developed the present invention. It was completed. That is, based on the total molar sum of all constituent monomers, 50 to 99.49 mol% of acrylamide and/or methacrylamide, and b) 0.5 to 20 mol% of water-soluble cationic monomers and/or their salts.
and C) 0.01 to 1 mol% of the crosslinking monomer is an essential monomer constituent, and d) the polymerization reaction is carried out in the presence of 0.01 to 3 ppm of copper ions based on the total weight of all constituent monomers. This is a method for producing a papermaking additive made of a water-soluble polymer, characterized by the following.

In the present invention, the above component a), acrylamide or methacrylamide, may be used alone, or
Although they may be used in combination, acrylamide is preferred from the economic point of view.9 Examples of the above b) water-soluble cationic monomer and/or salts thereof include dimethylamine ethyl (meth)acrylate and dimethylaminopropyl (meth)acrylate. , diethylaminoethyl (meth)acrylate, diethylaminopropyl (meth)acrylate, dimethylaminopropyl (meth)acrylamide, diethylaminopropyl (meth)acrylamide and other vinyl monomers having a tertiary amino group, or their hydrochloric acid, sulfuric acid or acetic acid, etc. Salts of inorganic or organic acids, or vinyl monomers having a tertiary amino group, and alkyl halides such as methyl chloride and methyl bromide, arylalkyl halides such as benzyl chloride and benzyl bromide, dimethyl sulfate, epichlorohydrin, etc.
Examples include vinyl monomers containing quaternary ammonium salts obtained by reaction with grading agents, and further cationic monomers having an allyl group such as dimethyldiallylammonium chloride.

Two or more of these monomers may be used in combination.

In addition, as the crosslinkable monomer C) above, methylene bis(
Bis(meth)acrylamides such as meth)acrylamide and hexamethylene bis(meth)acrylamide, di(meth)acrylates such as ethylene glycol di(meth)acrylate and polyethylene glycol di(meth)acrylate, divinyl adipate, sebacic acid Monomers with two double bonds such as divinyl esters such as divinyl and divinylbenzene, monomers with three double bonds such as trimethylolpropane triacrylate, N,N-diallylacrylamide, etc. Vinyl monomers having a reactive functional group such as methylol(meth)acrylamide, glycidyl(meth)acrylate, N-methoxymethyl(meth)acrylamide, N-methoxybutyl(meth)acrylamide, etc. can be used. - may be used in combination of two or more types.

The content of the monomer components shown in a) to C) above is 50 to 99.49 with respect to the total molar sum of all constituent monomers.
mol%, b) is 0.5 to 20 mol%, C) is 0.01 to
1 mol% and preferably a) is 55 to 98.98
mol%, b) is 1 to 15 mol%, C) is 0.02 to 0.
It is 8 mol%.

Furthermore, in addition to the above monomers a) to C), any anionic or nonionic monomer copolymerizable with these monomers can be introduced.

Examples of anionic hexamers that can be introduced include acrylic acid,
Examples include monocarboxylic acids such as methacrylic acid, dicarboxylic acids such as itaconic acid, maleic acid, and fumaric acid, and sulfonic acids such as acrylamide methylpropanesulfonic acid.

Examples of nonionic monomers that can be introduced include styrene, acrylonitrile, vinyl acetate, and droxyethyl (
Examples include (meth)acrylate derivatives such as meth)acrylate, hydroxypropyl (meth)acrylate, and various methoxypolyethylene glycols.

d) Copper ions necessary for copolymerizing the above monomers a) to C) and, if necessary, any anionic or nonionic monomer copolymerizable with these monomers, are added during the polymerization reaction. The type of copper compound introduced into the polymerization system is not particularly limited as long as it is present as an ion in the polymerization system, and the valence of the copper ion may be either monovalent or divalent.

Specific examples of copper compounds include inorganic copper salts such as cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, cupric iodide, copper sulfate, copper nitrate, and copper carbonate. , copper formate, copper acetate, copper citrate, copper oleate, copper naphthenate, and other organic acid salts of copper. These are only one type
Alternatively, it is also possible to use a mixture of two or more types.

The amount of d) copper ions introduced into the polymerization system is usually 1 to 3 ppm, preferably 0.02 to 2 ppm, and more preferably 0.02 to 2 ppm, based on the total weight of all constituent monomers. is 0.05 to lppm. 0. O1ppm1
ppm does not have the expected effect, and if it exceeds 3 ppm, it becomes impossible to obtain the desired polymer aqueous solution, which is disadvantageous.

Next, the above monomers are polymerized in the presence of copper ions to produce an acrylamide polymer, and radical polymerization is preferred as the polymerization method.

Although polar solvents such as water, alcohol, and dimethylformamide can be used as the polymerization solvent, water-soluble polymerization is preferable from economical considerations. The monomer concentration at that time is 2 to 30% by weight, preferably 5 to 30 mol%.

The polymerization initiator is not particularly limited as long as it dissolves in the polymerization solvent; specific examples include ammonium persulfate, potassium persulfate, hydrogen peroxide, and tert-butyl peroxide. In this case, sulfites, bisulfites, although they can be used alone.

Alternatively, it is preferable to use it as a redox polymerization initiator in combination with an organic amine such as N, N, N'', N-tetramethylethylenediamine, or a reducing agent such as a reducing sugar such as aldose or ketose. Compounds can also be used, specifically azobisisobutyronitrile, 2゜2゛-azobis-2-amidinopropane hydrochloride, 2,2-1azobis-2,4-dimethylvaleronitrile, 4,4- Examples include -azobis-4-cyatubaleic acid and its salts.

Two or more types of these initiators can also be used in combination. In addition to the initiator, a chain transfer agent such as isopropyl alcohol or allyl alcohol can also be used as appropriate.

The amount of initiator added is from 0°01 to the total weight of seven months.
10% by weight, preferably 0.02-8% by weight.

When used as a redox polymerization initiator, the amount of reducing agent added is 0.1 to 10'0 on a molar basis relative to the initiator.
% is preferable.

In the case of a single polymerization initiator, the polymerization temperature is approximately 30 to 90°C.
°C, and in the case of redox polymerization initiators, it is lower, approximately 5 to 50 °C. Further, it is not necessary to maintain the same temperature during polymerization, 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 in 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.

"Function" The papermaking additive of the present invention thus obtained is added to the pulp slurry, and by adsorption, it has a wide pH range.
In this area, it has a high paper strength enhancement effect and significantly improves various requirements related to paper manufacturing.

Although the reason is not necessarily clear, it is thought to be as follows.

Acrylamide-based polymers with cross-linked hexamers have a partially three-dimensional structure, and compared to conventional relatively linear polymers without cross-linked structures, the effective volume of the polymer in the papermaking system is large. Furthermore, it is estimated that by increasing the contact area between fibers after polymer adsorption, the paper strength-enhancing effect and various requirements related to paper manufacturing can be significantly improved.

Furthermore, it is presumed that by adding copper ions to the polymerization system, the crosslink density of the polymer is optimized and a partially crosslinked polymer having a more uniform effective volume is synthesized. Therefore, it is presumed that various performances are further improved compared to partially crosslinked polymers synthesized by conventionally known methods.

[Example] Next, the present invention will be specifically explained by dividing it into Examples and Applied Examples, but the present invention is not necessarily limited to the following Examples and Applied Examples. % and ppm
Unless otherwise specified, all references are to percent by weight and ppm by weight.

Example 1 Acrylamide 67,36(], dimethylaminoethyl methacrylate 7.85Q, methylene his-acrylamide 0.154Q and lppm C were added to a fourth flask equipped with a stirrer, reflux condenser, thermometer and nitrogen gas inlet tube.
USO4 aqueous solution as Cu ion sealant 0.2p
Prepare it so that it becomes p garden, add water and make the total amount 490. OQ and adjusted to pH 4.5 with 10% sulfuric acid. Thereafter, the internal temperature was raised to 45° C. without blowing in nitrogen gas. While stirring, 022g of ammonium persulfate and 010Ω of sodium bisulfite were added to start polymerization9.
After that, the temperature was kept at 85°C, and 3 hours after the start of polymerization, water was added, pH was adjusted, and the polymerization was completed.
A stable polymer A-1 was obtained.

In addition, 1 ppg+ CuSO4 aqueous solution was added to Cu
0.5 ppm of countermonomer as ions, 1.01) p-
The same procedure as above was carried out except that the amount of polymerization initiator was changed accordingly, and
2, A-3 was obtained.

The properties of Polymers A-1 to A-3 are summarized in Table 1 together with the polymers obtained in Examples 2 to 4 and Comparative Examples 1 to 4 below.

Comparative Example 1 11) I) Polymer a-1 was obtained in the same manner as in Example 1, except that no CuSO4 aqueous solution was added and the amount of polymerization initiator was changed accordingly.

Polymer a-2 was obtained by carrying out the same operation as in Example 1, except that the lppm Cu5O aqueous solution and methylene bisacrylamide were not added, and the amount of polymerization initiator was changed accordingly.

Example 2 Acrylamide 65.25 (], methacryloyloxyethyldimethylbenzyl ammonium chloride 14.2 (]), itaconic acid 3.9Q methylene were placed in a four-bottle flask equipped with a stirrer, 5 reflux condensers, a thermometer, and a nitrogen gas inlet tube. Bisacrylamide 0154g and 1pp-Cu5
O, aqueous solution as Cu ion counter monomer 02 ppih
Add water to make a total volume of 49,000, then add 20
The pH was adjusted to 4.5 with % NaOH. Then, while blowing nitrogen gas, raise the internal temperature to 45°C. While stirring, add 029 g of ammonium persulfate, Ti
Polymerization was started by adding fLtm sodium hydride (1,131; 1).Then, the temperature was kept at 85°C, and after the start of polymerization,
After 3 hours, water was added, pH was adjusted, and polymerization was completed to obtain stable polymer B-1.

In addition, 1 ppl CIJSO4 aqueous solution was added to Cu
As an ion, a pair of salts (0.5 ppm, 1.0 pl)
Polymer B-
2, B-3 was obtained.

Comparative Example 2 Polymer b-1 was obtained by carrying out the same operation as in Example 2, except that the 1 ppm CuSO4 aqueous solution was not added and the amount of polymerization initiator was changed accordingly.

Examples 3 and 4 As shown in Table 1, the amount of Cu ions relative to monomer was 0.5.
ppm, the monomer composition was changed, and the same operations as in Examples 1 and 2 were performed, except that the amount of pH adjuster and the amount of polymerization initiator were changed accordingly, to obtain polymers C-1 and D-1. .

Comparative Examples 3 and 4 Examples 3 and 4 except that 1 ppl CuSO4 aqueous solution was not added and the amount of polymerization initiator was changed accordingly.
Polymers c-1 and d-1 were obtained by performing the same operation as above.

Application Example 1 and Comparative Application Example I A sulfuric acid band was added to a 1% pulp slurry of recycled corrugated paper beaten in 450 ml of CSF to adjust the pH to three levels. 0 sulfuric acid band to the pulp of 1% pulp slurry
When the pH of 5%, 1%, and 2% added was 6.
It was 6.5.5.4.8. To each of the 1% pulp slurries, the polymer produced in Example 1, that is, the papermaking additive, and the polymer produced in Comparative Example 1, that is, the papermaking additive, were added to each of the 1% pulp slurries so that the solid content of the pulp was 0.5%. Added. These pulp slurries were processed using a Tarapee standard sheet machine to produce a basis weight of 150Q/m2.
paper, and measured the bursting strength according to JIS-P-8112, the compressive strength according to JI 5-ps 126, and the Z-axis strength using an internal bond tester manufactured by Kumagai Riki Kogyo Co., Ltd. The results are shown in Table 2. Blank indicates that neither sulfate nor papermaking additives were added.

Application Examples 2 to 4 and Comparative Application Examples 2 to 4 The papermaking additives added to the pulp slurry were
The procedure was the same as Application@1 and Comparative Application Example 1 except that the papermaking additive produced in 4 or the papermaking additive produced in Comparative Examples 2 to 4 was used. The results are shown in Tables 3 and 4.

Application Example 5 and Comparative Application Example 5 Sulfuric acid band was added to a 1% pulp slurry of corrugated hole waste paper beaten to 16 Oml of C8F, and the pH was adjusted to 55.

Add 0 sodium sulfate to this 1% pulp slurry.
, 2000.40001), the electrical conductivity of each 1% pulp slurry was 018.263.
．． 509■S/c was honored. The papermaking additive produced in Example 1 and the papermaking additive produced in Comparative Example 1 were added to each of the 1% pulp slurries so that the solid content was 0.5% based on the pulp. These pulp slurries were made into paper with a basis weight of 150 Illm2 using a Tarapee standard sheet machine, and JIS-P-8
The bursting strength was measured according to No. 112, the compressive strength was measured according to JIS-P-8126, and the biaxial strength was measured using an internal bond tester manufactured by Kumagai Riki Kogyo Co., Ltd. The results are shown in Table 5. Note that the blank indicates that sulfuric acid, sodium sulfate, and papermaking additives were not added.

Application Examples 6 to 8 and Comparative Application Examples 6 to 8 The papermaking additives added to the valve slurry were
Application Example 5 and Comparative Application Example 5 are the same except that the papermaking additive produced in 4 or the papermaking additive produced in Comparative Examples 2 to 4 was used. The results are shown in Tables 6 and 7.

Table 4 Table 3 Table 5 Table 6 "Effects of the Invention" As shown in Tables 2 to 4, the papermaking additive according to the present invention can provide stable and high paper strength under different papermaking pH conditions. .

Furthermore, as shown in Tables 5 to 7, even in a papermaking system where a large amount of inorganic salt is present, there is less variation in effectiveness compared to a system with a small amount of inorganic salt, and high paper strength can be provided.

As described above, it is clear that the papermaking additive produced using the production method according to the present invention has excellent performance.

Patent applicant: Mitsui Toatsu Chemical Co., Ltd. Table 7

Claims (1)

[Claims] 1) Based on the total molar sum of all constituent monomers, a) 50 to 99.49 mol% of acrylamide and/or methacrylamide, and b) 0.5 of a water-soluble cationic monomer and/or a salt thereof. ~20 mol%, and c) 0.01 to 1 mol% of a crosslinking monomer as essential monomer constituents, and d) Polymerization in the presence of 0.01 to 3 ppm of copper ions based on the total weight of all constituent monomers. A method for producing a papermaking additive comprising a water-soluble polymer obtained by carrying out a reaction.