JPS636198A - Cationic paper strength enhancer - 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] [Industrial application field] The present invention relates to a cationic paper strength enhancer.

Partially hydrolyzed BoIJ N-vinylformamide or poly-N-vinylacetamide is a highly stable cationic water-soluble polymer with a polyvinylamine structure in its molecule, and is used in neutral papermaking. Effective as a force enhancer.

[Conventional technology]

Conventionally, in acidic papermaking methods, sulfuric acid is used as a fixing agent for anionic polyacrylamide used as a paper strength enhancer, resulting in wear and tear of the paper machine, deterioration of paper during storage,
There were problems with wastewater, etc. For this reason, papermaking methods under neutral or weakly basic conditions that avoid these problems and can use inexpensive calcium carbonate as a filler are being considered.

[Problem that the invention seeks to solve]

The paper strength J-1 strength agent used under such conditions requires a paper strength agent made of a cationic water-soluble polymer that itself has excellent fixing properties to pulp. υ, a cationic paper strength increaser with excellent fixing properties and good stability is desired.

It is known that the Hofmann decomposition product of polyacrylamide, which has a polyvinylamine structural unit in its molecule, exhibits an interesting paper strength enhancement effect.

However, after going through strong basic conditions during production, it is difficult to avoid amphotericization due to side reactions, which poses performance problems, and it is not stable in aqueous solution form due to the shadow of the hypohalite used during production. There was a problem with sexuality.

[Means for solving problems]

The present invention aims to provide a cationic paper strength enhancer having a polyvinylamine structural unit in its molecule and exhibiting excellent subsequent fixing properties to pulp. Consists of a structural unit represented by the general formula (1) and CI[], (in the formula, X- represents an anion) (in the formula, R represents a hydrogen atom or a methyl group). ): The molar ratio of (n) is j:rij~ri0:10
/0.0 in normal saline. Reduced viscosity measured at 25°C as /g/d1 solution is 0, /~/Oa1/
This is achieved by using a cationic paper strength agent made of a water-soluble polymer.

The present invention will be explained in detail below.

Structural unit of the water-soluble polymer CI) in the formula, X″″Fi
Represents anions, specifically hydroxide ions, chloride ions, bromide ions, iodine ions, nitrate ions, sulfate ions, nonaphosphate ions, sulfamate ions, and water-soluble alkyl sulfates, alkanesulfonic acids, Examples include organic acid ions made of carboxylic acid.

The above-mentioned water-soluble polymer FiN-vinylformamide or N-vinylacetamide is produced by denaturing the polymer obtained by polymerization under acidic or basic conditions. A water-soluble polymer in which R in the structural unit of general formula (IF) obtained by modifying the polymer is a hydrogen atom is preferred.

Generally, when a cationic paper strength enhancer has a high proportion of cationic structural units in the molecule or has a large molecular weight, there is a tendency that the formation of pulp during paper making becomes poor. However, the paper strength enhancer of the present invention exhibits an excellent paper strength enhancing effect over a very wide range, and the ratio of structural units (1):(n) is from j:9j to 0:/o, preferably 10 :RiQ
Polymers in the range ˜70:30 are used. In addition, even with a high molecular weight, it does not cause uneven formation and exhibits an excellent paper strength enhancing effect. /g/41 solution, the value of reduced viscosity measured at 2j°C is 0. /~
/Oa1/g, preferably in the range of O0j to 1617H.

The cationic paper strength agent of the present invention is, for example, N-vinylformamide or N-vinylacetamide! −
A water-soluble polymer obtained by polymerizing a 60% by weight aqueous solution in the presence of a radical polymerization initiator at 7B degrees of Hiro Q ~/θ°C is denatured under acidic or basic conditions. can be obtained.

As a radical polymerization initiator, a general initiator used for water-soluble vinyl monomers is usually used, but water-soluble azo compounds may be used to synthesize the polymer in terms of yield. preferable. Examples of preferred polymerization initiators include co, co'-azobis-amidinopropane hydrochloride or acetate, tei-'-azobis-≠-cyanovaleric acid sodium salt, azobis-N,N'-di Examples include hydrochloride and acid salt of methyleneisobutyramidine. The amount used is usually N-vinylacetamide, N-
It ranges from 0.0% to 0.0% by weight based on the weight of vinyl acetamide. The modification reactions of the obtained polymer include hydrolysis,
Although any reaction that converts a zamide group into an amino group, such as albicollysis, can be used, in order to obtain an aqueous product, a method of hydrolyzing an aqueous polymer solution is used. The hydrolysis reaction may be basic or acidic. Although the basic hydrolyzate can be used as it is, it can be stored more stably by neutralizing it by adding an acid after the reaction is completed. Acid hydrolysates can be used as they are, but if too much acid is used,
It is desirable to neutralize excess acid. The hydrolysis reaction is usually carried out at a polymer concentration of 5 to 30% by weight.

The amount of base or acid used is 0.0! based on the equivalent weight of amide groups in the polymer. ”-2 times the mole range, depending on the desired modification rate. The hydrolysis reaction is carried out in the range of ≠θ~7
It is carried out at a temperature of 0.000C. The aqueous solution of the cationic polymer thus obtained is extremely stable, its performance does not deteriorate even after long-term storage, and it exhibits an excellent paper strength enhancing effect.

As a method for using the cationic paper strength enhancer of the present invention, any conventionally known paper strength increase method can be used. Paper may be made by adding it to pulp slurry as an internal additive, or it may be applied to wet paper or dry paper using a roll coater, size press, or dipping machine. The effect is remarkable.

When used as an internal additive, for example, 0.0 to 3% by weight of pulp slurry based on the dry weight of the pulp! %
O
15~2? Paper is made after adding it in the form of an aqueous solution. If necessary, sulfuric acid or an anionic paper strength enhancer may be used in combination. It is not limited to the type of pulp, and can be used for ground pulp, sulfide pulp, kraft pulp, disintegrated waste paper, etc. Furthermore, there are no restrictions on the type of sizing agent or filler.

The cationic paper strength enhancer of the present invention is extremely stable even in the form of a dilute aqueous solution, regardless of the quality of the dissolved water. Also,
It is a paper strength enhancer that is stable even under weakly alkaline papermaking conditions using calcium carbonate as a filler and does not lose its effectiveness and is excellent in neutral or weakly alkaline papermaking conditions.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

(Production of partially hydrolyzed polyN-vinylformamide) A stirrer, a nitrogen introduction tube, and a cooling tube were equipped. A 200tR1 four-loop flask was charged with 70g of N-vinylformamide and 9.7g of demineralized water. In nitrogen gas flow,
After raising the temperature to 0°C while stirring, add 2.2% of 10% by weight.
'-Azobis-2-amidinopropane dihydrochloride aqueous solution 0
．． J gf was added and held at 60° C. for φ time. A predetermined amount of concentrated hydrochloric acid was added to the obtained aqueous polymer solution, mixed uniformly, and kept at 20° C. for an hour to obtain a partially hydrolyzed product. A portion of the product was diluted by adding demineralized water and sodium hydroxide to prepare an aqueous polymer solution having a pH of 7% by weight, and the solution was subjected to a papermaking test.

A part of the product was dehydrated and precipitated in methanol, and then dried in vacuo to obtain a solid polymer. This was used to measure the composition and viscosity of the aqueous solution.

(Production of partially hydrolyzed poly-N-vinylacetamide) In a CO00D four-bottle flask equipped with a stirrer, a nitrogen introduction tube, and a cooling tube, 70 g of N-vinylacetamide and 39,
7 g of demineralized water was added. The temperature was raised to 30°C with stirring under nitrogen gas flow, and then 0.3 g of 2.2'-azobis-coamidinopropane hydrochloride aqueous solution of 10% was added, and the mixture was heated to 30°C at 60°C. Holds time. A predetermined amount of concentrated hydrochloric acid was added to the obtained aqueous polymer solution, mixed uniformly, and then heated under reflux for 6 hours to obtain a hydrolyzate. A portion of the product was diluted by adding demineralized water and sodium hydroxide to prepare a 7% by weight aqueous polymer solution with a pH of 5, which was subjected to a papermaking test.

A part of the product was dehydrated and precipitated in an inproper tool, and then dried under vacuum to obtain a solid polymer. This was used to measure the composition and viscosity of the aqueous solution.

Note 1) Measurement of edge viscosity A solid polymer was added to a specified saline solution at 0.7 g/dl. It was measured using an Ostwald viscometer at 2J°C.

Reduced viscosity ηsp/c = (t − to )/lo/θ
, / (d1/g) tO: Descending rate of edible water t: Descending rate of polymer solution Note) Measurement of hydrolysis rate Solid polymer was added to distilled water to 0.7% by weight at 0 degrees. Dissolved. This aqueous solution j, Og was diluted to 200d using demineralized water, and the pH of the solution was adjusted to 3 using diluted hydrochloric acid.
It was calculated from the titration value obtained by a colloid titration method using polyvinyl potassium sulfate with a normality of /≠00 and toluidine blue as an indicator.

Examples/~/2, Comparative Examples/~3 11 were determined using the Canadian Standard Method. L with P Fisheries≠35-
The BKP/thi slurry was placed in a beaker of s 00 tttl, and while stirring, a 7% by weight aqueous solution of a cationic paper strength agent made of the polymer produced by the above method was added to the pulp at a concentration of 0.0%. t% of reference weight was added and held for 7 minutes. TAPP this
Paper with a basis weight of Og was made using an I standard square paper machine. The obtained wet paper was dried for 3 minutes using a drum dryer at 720°C. After the paper was left to stand under conditions of -20°C and relative humidity of 6θ, the specific rupture degree and tearing length were measured according to -PI//J from JIS-P#//, 2 and J.

Here, Sl: Breaking strength (kg/ad) W: Basis weight of test paper (g/m″) S2: Tensile strength [Cape] B: Width of test piece [Simplified] Type of polymer used, Table 1 shows the composition, physical properties, and paper strength enhancement effect of the obtained paper.

Table 1 (**, -methacryloyloxyethyltrimethylammonium chloride/acrylamide = 20770
Copolymer Examples 73 to /j, Comparative Example i In the papermaking method of Example 1, Example / Paper was made in the same manner as above, and the paper strength of the obtained paper was measured.

Type, composition, and physical properties of the polymer used! The effect of increasing the paper strength of the obtained paper is shown in Table 2.

Mco table (*1 Co-methacryloyloxyethyltrimethylammonium chloride/acrylamide = λ0/♂0 copolymer Example/1~/7, Comparative Example 7 Measured by Canadian standard method, p* degree φ00H7 in a beaker After adding the chemicals listed below while stirring,
As in Example 1, a paper having a basis weight of tog was made using TAPP Nistandart Kakuju Paper. What is the pH during paper making? ,! Met.

When added to pulp aqueous solution # Added amount Cationic starch /, 0% by weight O0j Jokei cationic paper strength agent 0. j Weight % 0.33 amount Chisizing agent (Fulkyl /, 0 weight arrogant Q, -wt% Keten Dairyo -) Filler retention improver 0. /Weight: 0.02 Weight: The paper strength of the obtained paper was measured in the same manner as in Example.

Table 3 shows the type of polymer used, its mending and physical properties, and the paper strength enhancing effect of the obtained paper.

Table 3 [Effects of the Invention] Partially hydrolyzed poly-N-vinylacetamide polymer has a cationic paper strength agent of the present invention comprising poly-N-vinylacetamide, which improves stability and paper strength. It is highly effective, has self-fixing properties, and greatly contributes to paper making methods under neutral and slightly alkaline conditions.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - Others/Names

Claims (1)

[Claims] (1) Consists of structural units represented by the following general formulas [I] and [II], ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] (In the formula, X^- represents an anion.) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [II] (In the formula, R represents a hydrogen atom or a methyl group.) The molar ratio of structural units [I]: [II] is in the range of 5:95 to 90:10. A cationic paper strength enhancer comprising a water-soluble polymer having a reduced viscosity of 0.1 to 10 dl/g measured at 25°C as a 0.1 g/dl solution in 1N saline.