JPH0611955B2 - Papermaking sizing agent dispersion - Google Patents

Description

The present invention relates to a sizing agent dispersion liquid for papermaking. More specifically, it relates to a sizing agent dispersion for papermaking in which a substituted cyclic dicarboxylic acid anhydride is stably dispersed with a specific dispersant.

[Conventional technology and problems]

Conventionally, rosin or reinforced rosin (maleated rosin) has been widely used as a sizing agent for papermaking. However, this rosin-based sizing agent has many problems because it requires fixing with aluminum sulfate. That is, fixing with aluminum sulfate is performed by using the papermaking water during papermaking.
Since the pH is low (acidic), the papermaking machine is largely damaged, the printability of the paper is deteriorated, and there is a possibility that the paper may be discolored due to long-term storage. Further, when calcium carbonate is used as the filler, the rosin-based sizing agent cannot be used because the calcium carbonate decomposes in an acidic solution. Since calcium carbonate is inexpensive and has a high degree of whiteness, it is known to be effective when used as a filler for paper, but its use is currently extremely limited due to the above reasons. Therefore, it has been desired to develop a neutral papermaking sizing agent that overcomes the above-mentioned drawbacks and does not deteriorate the paper quality and can use calcium carbonate.

In recent years, various neutral sizing agents have been proposed in order to achieve this object, but many patents have been filed regarding the use of a substituted cyclic dicarboxylic acid anhydride or a substituted dicarboxylic acid (or a salt thereof) dispersed in water. Has been done.

In particular, a dispersion of a substituted cyclic dicarboxylic acid anhydride is known to be used as a sizing agent for papermaking or a fiber treating agent, and in Japanese Patent Publication No. Sho 53-36044, cationic starch and a specific nonionic interface are used. A method is disclosed in which a substituted succinic anhydride is stably dispersed in water by using an activator. However, when a cationic starch is used, it must be cooked in advance, diluted with a large amount of water, and then the substituted cyclic dicarboxylic acid anhydride must be dispersed by a specific emulsification disperser, which requires a large amount of equipment. In addition, a high shearing force is required to control the average particle size of the dispersed particles, which has a drawback of increasing energy cost. In addition, a specific nonionic surfactant, here polyoxyethylene aryl ether, is used in combination, but the average particle size of the dispersed particles and the particle size distribution control (average particle size of about 1 μm, It is not easy to keep the particle size distribution sharp and to keep particles of 5 μm or more almost empty). Furthermore, even if the average particle size and particle size distribution can be controlled, a large amount of cationic starch must be used, which is not always satisfactory in view of the cost of chemicals.

[Means for solving problems]

As a result of intensive studies to improve this point, the present inventors have found that by using a specific dispersant, the average particle size of the substituted cyclic dicarboxylic acid anhydride particles in the aqueous solution is about 1 μm, and the particle size distribution is Being sharp and capable of keeping particles of 5 μm or more almost completely absent, and this dispersant is cationic, and 20 to 10% of cationic starch is used.
It is possible to effectively disperse the substituted cyclic dicarboxylic acid anhydride in a small amount with a cationic charge density of 0 times, and it is also possible to synthesize a dispersant having a different cationic charge density by changing the monomer composition ratio. Therefore, the inventors have found that the use of this dispersant can control the ζ-potential of the substituted cyclic dicarboxylic acid anhydride particles, so that the optimum size effect can be exhibited in the papermaking process, and the present invention has been completed.

That is, the present invention is represented by the general formula (I) (In the formula (I), R ′ is a linear or branched alkyl group having 8 to 36 carbon atoms, an alkenyl group, an aralkyl group or an aralkenyl group, and n is 2 or 3.) Hydrophobic vinyl monomer (A) 1 to 15 mol% having a dicarboxylic acid anhydride (I) and a hydrocarbon group having 10 to 28 carbon atoms as a dispersant, aromatic vinyl monomer (B) 10 to
50 mol%, cationic vinyl monomer (C) 10 to 50 mol%
And water-soluble nonionic vinyl monomer (D) 10 to 50 mol%
The present invention provides a sizing agent dispersion for papermaking, which comprises the water-soluble polymer (II) as an essential component.

As the substituted cyclic dicarboxylic acid anhydride (I) which is one of the essential components constituting the present invention, any conventionally known substituted cyclic dicarboxylic acid anhydride can be used. For example, a linear or branched alkyl group having 8 or more carbon atoms, an alkenyl group,
A substituted cyclic dicarboxylic acid anhydride having an aralkyl group or an aralkenyl group, a compound obtained by the reaction of α-olefin, an internal olefin, propylene, butylene and the like with maleic anhydride or a compound obtained by hydrogenating the compound. Can be mentioned. Specifically, 1-propyl-2-tridecenyl succinic anhydride, 1-
Ethyl 2-tetradecenyl succinic anhydride, 2-methyl-
2-pentadecenyl succinic anhydride, 1-octyl-2-decenyl succinic anhydride, poly (3-8) propylenyl succinic anhydride, poly (3-8) butenyl succinic anhydride, n-hexa Examples thereof include decenyl succinic anhydride and isooctadecenyl succinic anhydride.

The dispersant or water-soluble polymer (II) according to the present invention has a carbon number of
Hydrophobic vinyl monomer having 10 to 28 hydrocarbon groups
(A), an aromatic vinyl monomer (B), a cationic vinyl monomer (C) and a water-soluble nonionic vinyl monomer (D) are obtained by polymerization, and each monomer in the polymerization product The ratio of the components is also important, (A) is 1 to 15 mol%, preferably 3 to 10 mol%, (B) is 10 to 50 mol%, preferably 20 to 40 mol%, and (C) is 10 ~ 50 mol%, preferably 20-4
0 mol%, (D) is 10 to 50 mol%, preferably 20 to 40 mol%
Must. With a water-soluble polymer in which the component ratio of each monomer is outside the above range, not only the substituted cyclic dicarboxylic acid anhydride (I) cannot be stably dispersed, but also the size performance effect cannot be expected.

As the hydrophobic vinyl monomer (A) having a hydrocarbon group having 10 to 28 carbon atoms according to the present invention, acrylic acid alkyl ester, methacrylic acid alkyl ester, carbon number 12 to 30
Α-olefin, fatty acid having a carbon number of 11 to 29 fatty acid vinyl ester, hydrocarbon group having a carbon number of 10 to 28 alkyl vinyl ether and the like, acrylic acid alkyl ester or methacrylic acid alkyl ester can be mentioned. It is preferable because it is easily polymerized.

The aromatic vinyl monomer (B) according to the present invention has the general formula (1) (In the formula, R ₁ represents a hydrogen atom, a methyl group or an ethyl group,
R ₂ represents a hydrogen atom, a chlorine atom, an ethyl group or a monochloromethyl group. ) Styrene and / or styrene derivative represented by

The cationic vinyl monomer (C) according to the present invention has the general formula (2) (In the formula, R ₃ represents a hydrogen atom or a methyl group, and R ₄ and R ₅
Represents an alkyl group having 1 to 3 carbon atoms, R ₆ is a hydrogen atom,
Represents an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms, Y represents an oxygen atom or -NH-, and Z represents an alkylene group having 1 to 4 carbon atoms or 2 to 4 carbon atoms.
Represents a hydroxyalkylene group, and X represents a halogen atom or an acid residue. ) Acrylic acid or methacrylic acid-based cationic monomer represented by

Examples of the compound represented by the general formula (2) include β-acryloyloxyethyl trimethylammonium salt, β
-Methacryloyloxyethyl trimethylammonium salt, β-acryloyloxyethyl dimethylethylammonium salt, β-methacryloyloxyethyl dimethylethylammonium salt and the like can be mentioned.

Examples of the water-soluble nonionic vinyl monomer (D) according to the present invention include acrylamide, methacrylamide, N-vinyl-2-pyrrolidone, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, polyethylene glycol monomethacrylate, and methoxypolyethylene glycol methacrylate. , Diacetone acrylamide, etc., but acrylamide or methacrylamide is preferable from the viewpoint of stability of the aqueous dispersion.

The water-soluble polymer (II) according to the present invention is the monomer
It can be obtained by polymerizing a mixture of (A), (B), (C) and (D) in a solvent in the presence of a radical initiator.
As the solvent, ethanol, isopropanol, tertiary butanol, methyl ethyl ketone, toluene or the like can be used. As the radical polymerization initiator, one that is soluble in the solvent used may be selected. For example, 2,2'-azobisisobutyl nitrile, 2,2'-azobis- (2,4-dimethylvaleronitrile) and the like can be used. The polymerization temperature is set by the decomposition temperature of the radical initiator.

In the present invention, the concentration of sizing agent in the dispersion is generally 0.
The content is in the range of 1 to 10% by weight, and the water-soluble polymer (II) is contained in an amount of 0.2 to 20% by weight with respect to the substituted cyclic dicarboxylic acid anhydride (I).
It is suitable to add in the ratio of.

In order to use the sizing agent of the present invention with good yield, it is effective to use a fixing agent, and a cationic polymer is preferable as the fixing agent. Preferred examples of the cationic polymer used as the fixing agent include cationized starch, cationized cellulose, polyamide-epihalohydrin-based polymer, polyethyleneimine, polyvinylpyridine and quaternary products thereof, polydimethylaminoethyl methacrylate and quaternary products thereof. , Polydiethylaminoethyl methacrylate and quaternary products thereof, or copolymers of these cationic monomers and acrylamide.

In practicing the present invention, the sizing agent dispersion of the present invention is added in an amount of 0.01 to 2% by weight, preferably 0.05 to 1% by weight, as a solid content based on the weight of pulp. It goes without saying that the addition level of these sizing agents is adjusted according to the sizing degree required for the target paper.

〔The invention's effect〕

The sizing agent dispersion for papermaking according to the present invention has excellent sizing performance and can reduce the amount of the fixing agent added.

〔Example〕

The present invention will be described in detail below with reference to production examples and examples, but the present invention is not limited to these examples and the like.

The parts in the examples are based on weight.

[Synthesis of dispersant (water-soluble polymer)]

Production Example 1 Stearyl methacrylate 4.1 parts, β-methacryloyloxyethyl dimethylethylammonium ethosulfate 37.3 parts, styrene 12.5 parts, acrylamide 10.5 parts and 2,2′-azobisisobutyl nitrite were added to 100 parts of isopropanol which had been heated and refluxed in advance. 150 parts of an isopropanol solution containing 1.0 part of ril was added dropwise over 2 hours.
After the reaction solution was heated and refluxed for 3 hours after the dropping, 200 g of water was added and diluted, and isopropanol was distilled off, and the concentration was adjusted to obtain an aqueous solution having a solid content of 20.0%.

Production Examples 2 to 5 and Specific Gravity Production Examples 1 to 5 Various copolymers were obtained in the same manner as in Production Example 1 by changing the total monomer amount to 0.4 mol and changing the monomer composition as shown in Tables 1 and 2. . The numbers in parentheses in Tables 1 and 2 represent the charged mol% of each monomer.

[Effect of Sizing Agent Dispersion] Examples 1 to 9 and Comparative Examples 1 to 7 (Preparation of Sizing Agent Dispersion) 0.5 to 0.5% of the water-soluble polymers produced in Production Examples 1 to 5 and Comparative Production Examples 1 to 5 were used. 1 part by weight of the substituted cyclic dicarboxylic acid anhydride 1
8 parts by weight were used and adjusted so as to be a 0.5% by weight aqueous solution, and the mixture was emulsified and dispersed by a high-pressure discharge homogenizer for experiments to obtain a sizing agent dispersion liquid. Table 3 shows the emulsified state of this dispersion. In addition, the particle size distribution measurement is a centrifugal automatic particle size distribution measuring device CAPA.
-500 (made by HORIBA, Ltd.) was used.

Measurement conditions: When obtaining the average particle size 0.4-4.0 μm When obtaining the ratio of particles of 5 μm or more 2.0-30 μm (Papermaking conditions) The paper used in this test was manufactured under the following conditions.

Pulp: LBKP (Canadian Standard Freeness 40
0ml) Sizing agent: 0.1% solid content based on pulp weight Fixing agent: 0.2% to 0.8% solid content based on cationized starch (commercial product) Yield improver: Cationic polyacrylamide polymer (commercial product) pulp Solid content 0.02% relative to weight Filler: Heavy calcium carbonate (commercial product) Adjusted so that the calcium carbonate in the paper is 12% and added. Fixing pH: 8.2 Order of addition: Pulp-filler-fixer-size -Yield improver Papermaking: Tappy square hand machine Press: 3.5Kg w / cm ² × 2 minutes Drying: Rotary dryer, 100 ° C × 40 seconds Weighing: 70g / m ² (size test) The sizing test was performed by the following method.

Size of test: stick man method (JIS-P-8122) by bending the four sides of the test strip above the boat-, floated in 2% NH ₄ SCN an aqueous solution. Simultaneously with the floating, a drop of 1% FeCI ₃ aqueous solution was dropped onto the test paper from above, and the time (seconds) until both aqueous solutions permeated the paper and contacted and three red spots of iron thiocyanate appeared were measured.

Table 4 shows the test results obtained by measuring the sizing degree of the paper made under the above conditions immediately after the paper making and after one day humidity control (20 ° C. × 60%). The sizing degree immediately after the papermaking indicates whether or not the rise of the size effect is good, and the higher the value, the better.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08F 220/34 MMR 7242-4J 220/56 MNC 7242-4J 220/60 MNH 7242-4J 226/10 MNN 7242-4J D21H 17/34

Claims (5)

[Claims] 1. A general formula (I) (In the formula (I), R'is a linear or branched alkyl group, alkenyl group, aralkyl group or aralkenyl group having 8 to 36 carbon atoms, and n is 2 or 3.) Hydrophobic vinyl monomer (A) 1 to 15 mol% having a cyclic dicarboxylic acid anhydride (I) and a hydrocarbon group having 10 to 28 carbon atoms as a dispersant, aromatic vinyl monomer (B) 10 to
50 mol%, cationic vinyl monomer (C) 10 to 50 mol%
And water-soluble nonionic vinyl monomer (D) 10 to 50 mol%
Sizing agent dispersion for papermaking containing water-soluble polymer (II) of 2. The hydrophobic vinyl monomer (A) having a hydrocarbon group having 10 to 28 carbon atoms is a compound selected from the group consisting of alkyl acrylate and alkyl methacrylate. The paper-based sizing agent dispersion described. 3. The aromatic vinyl monomer (B) has the general formula (1). (In the formula, R ₁ represents a hydrogen atom, a methyl group or an ethyl group,
R ₂ represents a hydrogen atom, a chlorine atom, an ethyl group or a monochloromethyl group. The paper-based sizing agent dispersion according to claim 1 or 2, which is a compound represented by the formula (1). 4. A cationic vinyl monomer (C) is represented by the following general formula (2): (In the formula, R ₃ represents a hydrogen atom or a methyl group, and R ₄ and R ₅
Represents an alkyl group having 1 to 3 carbon atoms, R ₆ is a hydrogen atom,
Represents an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms, Y represents an oxygen atom or -NH-, and Z represents an alkylene group having 1 to 4 carbon atoms or 2 to 4 carbon atoms.
Represents a hydroxyalkylene group, and X represents a halogen atom or an acid residue. ) A compound represented by the following claims: Claims 1 to 3
A papermaking sizing agent dispersion according to any one of items. 5. The water-soluble nonionic vinyl monomer (D) is acrylamide, methacrylamide, N-vinyl-2-pyrrolidone, 2-hydroxyethyl methacrylate, 2-
A compound selected from the group consisting of hydroxyethyl acrylate, polyethylene glycol monomethacrylate, methoxypolyethylene glycol methacrylate and diacetone acrylamide.
The sizing agent dispersion liquid for papermaking according to any one of item 4.