JPH0711119B2 - 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.

[Prior Art and Problems] 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 whiteness, it is known that it is effective when used as a filler for paper, but its use is currently extremely limited for 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 papermaking sizing agent 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 has to be used, which is not necessarily 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 invention has the 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. ] A substituted cyclic dicarboxylic acid anhydride (I) represented by the following formula, a cationic surfactant (A) having a hydrocarbon group having 4 to 28 carbon atoms and a polymerizable functional group as a dispersant, and a copolymerizable cation The present invention provides a sizing agent dispersion for papermaking, which comprises a water-soluble copolymer (II) of a polymerizable monomer (B) and a copolymerizable nonionic monomer (C) 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, 1-ethyl-2-pentadecenyl succinic anhydride, 1-octyl-2-decenyl succinic anhydride, poly (3-8) propylene succinic anhydride And poly (3-8) butenyl succinic anhydride, n-hexadecenyl succinic anhydride, isooctadecenyl succinic anhydride, and the like.

The dispersant according to the present invention, that is, the water-soluble copolymer (II) is a cationic surfactant (A) having a hydrocarbon group having 4 to 28 carbon atoms and a polymerizable functional group, a copolymerizable cationic monomer. As a cationic surfactant (A) which is a copolymer of (B) and a copolymerizable nonionic monomer (C), having a hydrocarbon group having 4 to 28 carbon atoms and a polymerizable functional group. Is a quaternary ammonium salt having a hydrocarbon group of 4 to 28 carbon atoms represented by the following general formulas (1), (2) and (3), which is acrylic acid or methacrylic acid, preferably methacrylic acid Good cationic surfactants are exemplified.

[In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ and R ₃
Represents an alkyl group having 1 to 3 carbon atoms, and R ₄ represents _{4 to 4} carbon atoms.
28 represents a hydrocarbon group, Y represents an oxygen atom or —NH—, Z and Z ′ represent an alkylene group having 1 to 4 carbon atoms or a hydroxyalkylene group having 2 to 4 carbon atoms, and X represents a halogen atom or Represents an acid residue. ] As the compound represented by the general formula (1), (2) or (3), 2-hydroxy-3-methacryloyloxypropyl-N, N, N-dimethylalkyl (C ₄ -C ₂₈ ) ammonium salt, 2 ′ - methacryloyloxyethyl -N, N-dimethyl-2-hydroxy-3- alkyl (C ₄ ~C ₂₈₎ propylammonium salt, 2'-hydroxy-3'-methacryloyloxy propyl -N, N-dimethyl-3-alkyl (C ₄ ~C ₂₈₎ can be mentioned propyl ammonium salts.

The cationic monomer (B) according to the present invention is preferably an acrylic acid or methacrylic acid type cationic monomer represented by the following general formula (4) or a vinylpyridine type cationic monomer represented by the following general formula (5). .

[In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ and R ₃
Represents an alkyl group having 1 to 3 carbon atoms, R ₅ 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. Examples of the compound represented by the general formula (4) include 2-dimethylaminoethyl methacrylate acid salt, 2-diethylaminoethyl methacrylate acid salt, 3-dimethylaminopropylacrylamide acid salt, and β-acryloyl. Examples thereof include oxyethyltrimethylammonium salt, β-methacryloyloxyethyltrimethylammonium salt, β-acryloyloxyethyldimethylethylammonium salt and β-methacryloyloxyethyldimethylethylammonium salt. Examples of the compound represented by the general formula (5) include vinyl pyridine acid salts and N-ethyl-4-vinylpyridinium ethosulfate.

As the nonionic monomer (C) according to the present invention, acrylamide, methacrylamide, N-vinyl-2-pyrrolidone, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, polyethylene glycol monomethacrylate, methoxypolyethylene glycol methacrylate, diacetone. Examples thereof include acrylamide, acrylonitrile and methacrylonitrile.

The proportion of each monomer component in the water-soluble copolymer is particularly important, (A) is 1 to 15 mol%, preferably 3 to 13 mol%, (B) is 10 to 70 mol%, preferably Suitably, 20 to 60 mol%, (C) is 10 to 70 mol%, preferably 20 to 60 mol%.

The dispersant according to the present invention, that is, the water-soluble copolymer (II) can be obtained by polymerizing a mixture of the monomers (A), (B) and (C) in a solvent in the presence of a radical initiator. As the solvent, ethanol, isopropanol, tertiary butanol, methyl ethyl ketone,
Toluene, water, etc. 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 amount is in the range of 1 to 10% by weight, and it is suitable to add the water-soluble copolymer (II) to the substituted cyclic dicarboxylic acid anhydride (I) in a proportion of 0.2 to 20% by weight.

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 its quaternary products, and copolymers of these cationic monomers with 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 2 parts of 100 parts of isopropanol which had been heated and refluxed in advance
-Hydroxy-3-methacryloyloxypropyl dimethylstearyl ammonium chloride 4.7 parts, β-methacryloyloxyethyl dimethylethylammonium ethosulfate 29.3 parts, acrylamide 19.6 parts and 2
100 parts of an isopropanol solution containing 0.5 part of -2'-azobisisobutylnitrile 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 to dilute, the isopropanol was distilled off, and the concentration was adjusted to a solid content of 20.0.
% Aqueous solution was obtained.

Production Examples 2 to 5 Various polymers were obtained in the same manner as in Production Example 1, except that the total amount of charged monomers was 0.2 mol and the monomer composition was changed as shown in Table 1. The numbers in parentheses in Table 1 represent the charged mol% of each monomer.

[Effect of Sizing Agent Dispersion] Examples 1 to 9 (Preparation of Sizing Agent Dispersion) 0.5 to 1 part by weight of the water-soluble copolymer produced in Production Examples 1 to 5 and substituted cyclic dicarboxylic acid anhydride 18 parts by weight, 0.
It was adjusted to be a 5% by weight aqueous solution and emulsified and dispersed by a high-pressure discharge type homogenizer for experiments to obtain a sizing agent dispersion liquid. The emulsified state of this dispersion is shown in Table 2. For the particle size distribution measurement, a centrifugal automatic particle size distribution measuring device CAPA-500 (manufactured by Horiba Ltd.) was used.

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

Pulp: LBKP (Canadian Standard Freeness 400
ml) Sizing agent: 0.1% solid content based on pulp weight Fixing agent: cationic starch (commercially available) Solid content 0.2 to 0.8% based on pulp weight Retention aid: Cationic polyacrylamide polymer (commercially available) pulp Solid content 0.02% relative to weight Filler: Heavy calcium carbonate (commercial product) Adjusted so that calcium carbonate in the paper is 12% and added. Fixing pH: 8.2 Order of addition: Pulp-filler-fixing agent-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) Size test The following method was used.

Sizing test: Stickhito method (JIS P-8122) Bend four sides of the test paper upward to form a boat shape and float it on a 2% NH ₄ SCN aqueous solution. Simultaneously with the floating, a drop of 1% FeCl ₃ aqueous solution was dropped onto the test paper from above, and the time (seconds) until both the aqueous solutions permeated the paper and contacted and three red spots of iron thiocyanate appeared were measured.

Table 3 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 front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area C08F 220/60 MNH 226/06 MNM

Claims (1)

[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. A substituted cyclic dicarboxylic acid anhydride (I) represented by the following formula and a hydrocarbon having 4 to 28 carbon atoms selected from the group of compounds represented by the following general formulas (1), (2) and (3) as a dispersant: Cationic surfactant having a group and a polymerizable functional group (A)
1-15 mol%, [In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ and R ₃
Represents a lower alkyl group having 1 to 3 carbon atoms, R ₄ represents a hydrocarbon group having 4 to 28 carbon atoms, Y represents an oxygen atom or —NH—
Z and Z'represent an alkylene group having 1 to 4 carbon atoms or a hydroxyalkylene group having 2 to 4 carbon atoms, and X represents a halogen atom or an acid residue. 10 to 70 mol% of one or more copolymerizable cationic monomers (B) selected from the group of compounds represented by the following general formulas (4) and (5), [In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ and R ₃
Represents an alkyl group having 1 to 3 carbon atoms, R ₅ 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. ] And acrylamide, methacrylamide, N-vinyl-
One or two or more selected from the group consisting of 2-pyrrolidone, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, polyethylene glycol monomethacrylate, methoxypolyethylene glycol methacrylate, diacetone acrylamide, acrylonitrile and methacrylonitrile. Polymerizable nonionic monomer (C) 10 to 70 mol% of water-soluble copolymer (I
A papermaking sizing dispersion containing I) as an essential component.