JP2761953B2 - Production method of rosin emulsion sizing agent - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for producing a rosin-based aqueous emulsion useful as a sizing agent for papermaking, and more particularly to a rosin-based emulsion sizing agent by a phase inversion method. The present invention relates to an improvement in the method for producing

[Related Art] In the papermaking industry in recent years, from the viewpoints of strengthening regulations on factory wastewater and reducing the cost of water use, it is desired to collect and reuse papermaking wastewater as much as possible. in this case,
The quality of water for papermaking is inevitably reduced, and it is extremely difficult for a saponified rosin sizing agent that has been widely used in the past to give a sufficient size effect to the formed paper. For this reason, emulsion type rosin sizing agents have been spotlighted in recent years.

[Problems to be Solved by the Invention] As a method for producing a rosin-based emulsion sizing agent, a high-pressure emulsification method in which a rosin-based substance is emulsified using a homogenizer, or a solution in which a rosin-based substance is dissolved in an appropriate organic solvent is used. A solvent distillation method in which an emulsifier is emulsified in an aqueous medium in the presence of an emulsifier, and then the organic solvent is distilled off, is known. There is known an inversion method for preparing an O / W emulsion by preparing an O-type emulsion and then adding water to invert the rosin-based material from a continuous phase to a dispersed phase.

However, the rosin-based emulsion sizing agent manufactured by the conventional inversion method requires a relatively large amount of a surfactant-based dispersant of 4 to 8% by weight based on the rosin-based material,
Uniform and fine rosin emulsion particles cannot be obtained. However, when such a rosin-based emulsion sizing agent is used in papermaking, foaming occurs in the papermaking system, and not only pinholes and the like are generated in the formed paper, but also pitch trouble is caused.

[Means for Solving the Problems] In order to solve the above problems, the present inventors have been able to obtain uniform and fine rosin-based emulsion particles even if the amount of the surfactant-based dispersant is reduced. As a result of repeated research on possible rosin-based substances, a mixture of a phenolic resin and reinforced rosin was used as a rosin-based substance in the inversion method, and a specific agent as described below was used as a drug for dispersing this rosin-based substance. It has been found that the use of such a quaternary copolymer alkali-neutralized salt makes it possible to obtain a homogeneous rosin emulsion having fine dispersoid particles without using any surfactant dispersant.

That is, the method for producing a rosin-based emulsion sizing agent according to the present invention comprises mixing a rosin-based material in a molten state with water containing a dispersant to form a dispersion in which the rosin-based material is a continuous phase and water is a dispersed phase. In a method for producing a rosin-based emulsion sizing agent, an aqueous emulsion in which water is a continuous phase and a rosin-based substance is a dispersed phase is obtained by forming a liquid and then inverting the phase by adding water to the dispersion. A mixture of a phenolic resin and a reinforced rosin as the rosin-based substance, and alkali neutralization of a quaternary copolymer composed of a styrene-based monomer, an acrylate, an acrylic acid and a methacrylic acid as the dispersant. It is characterized by using a salt.

The amount of the phenolic resin mixed with the reinforced rosin is in the range of 5 to 20% of the weight of the reinforced rosin.

In the method of the present invention, the phenolic resin refers to an alkyl phenol formalin addition condensate, a phenol-modified petroleum resin, and the like, and the molecular weight thereof is about 500 to 2,000, preferably about 1,000. Incidentally, an alkylphenol formalin addition condensate can be produced by adding formaldehyde to an alkylphenol to produce a methylolated alkylphenol and then subjecting it to a condensation reaction of methylol groups to produce a large amount. In addition, phenol-modified petroleum resin, by reacting phenol or phenol compound to petroleum resin,
Alternatively, in the presence of phenol or a phenol compound,
By producing a petroleum resin, a phenol-modified petroleum resin having a hydroxyl group in the molecule can be obtained, and its molecular weight can be adjusted by the molar ratio of the reactants and the amount of the catalyst added.

As the fortified rosin, those obtained by reacting a rosin such as a gum rosin or a tall oil rosin with an α, β-unsaturated polybasic acid by a known method can be used. Examples of the α, β-unsaturated polybasic acid include fumaric acid, maleic anhydride, itaconic acid, acrylic acid, methacrylic acid, and the like. Fumaric acid addition is most preferable, and the addition amount is 6 to 15%. Preferably it is in the range of 9 to 13%. In the present invention, a part of the reinforced rosin can be replaced with a phenol resin-modified reinforced rosin, if desired.

In the present invention, as a chemical for dispersing the above-mentioned rosin-based substance in an aqueous medium, an alkali neutralized salt of a quaternary copolymer composed of a styrene-based monomer, an acrylate, an acrylic acid and a methacrylic acid is used. Here, styrene-based monomers include styrene, vinyl toluene, α
-Or β-methylstyrene, isopropenyltoluene, and the like, and one or more of these can be used. Of these, the use of styrene is most preferred. In addition, as the acrylate, a general formula CH ₂ CRCR ₁ —COOR ₂ where R ₁ is hydrogen or a methyl group, and R ₂ is a linear or branched alkyl group or cycloalkyl group having 1 to 18 carbon atoms. Wherein R ₂ has 4 to 4 carbon atoms
The use of a compound which is an alkyl group of 8 is preferred.

% By weight of each monomer constituting the above quaternary copolymer
Is 50-70% of styrene monomer, acrylic ester
10-30%, acrylic acid 10-15%, methacrylic acid 10-15%
Within the range.

If the amount of the acrylate is 10% or less or 30% or more, the resulting copolymer cannot be expected to have sufficient dispersibility in rosin-based substances. Further, the ratio of acrylic acid to methacrylic acid is preferably in the range of 4/6 to 6/4. If the ratio deviates from this range, even if the amounts of the other two components fall within the predetermined range. Even so, the resulting copolymer cannot exhibit sufficient dispersing ability for rosin-based materials.

The quaternary copolymer can be prepared by a usual polymerization method, but an emulsion polymerization method is particularly preferable. As an emulsifier for emulsion polymerization, an anionic surfactant and / or a nonionic surfactant having a molecular weight of 1,000 or less is generally used. It is optimal to use about 15,000 polyoxyethylene polyoxypropylene.

In the emulsion polymerization, persulfates, hydrogen peroxide and the like are used as a polymerization initiator in a usual manner at a ratio of 1 to the weight of the monomer mixture.
Use about 5%. In this case, if necessary, a reducing agent such as a sulfite can be used in combination, and in some cases, an oil-soluble peroxide compound or an azo compound can be used in combination. Further, for the purpose of adjusting the molecular weight of the produced copolymer, mercaptans, thioglycolates,
A chain transfer agent such as carbon tetrachloride and isopropyl alcohol can be used in an appropriate amount according to the polymerization conditions. The amount of water added at the start of the emulsion polymerization is 65 to
90% by weight, preferably maintained in the range of 70-75% by weight, 50%
The desired quaternary copolymer can be obtained by completing the polymerization reaction at a temperature of about 95 ° C.

By neutralizing this copolymer in the usual manner, a dispersant particularly effective for the rosin-based substance of the present invention can be obtained, but in neutralization, 50 to 100% of the neutralization equivalent is neutralized. Is preferred. As the neutralizing agent, alkaline compounds such as sodium hydroxide, potassium hydroxide, ammonia, and amines are used alone or in combination.

The alkali neutralized salt of the quaternary copolymer thus prepared can be used in the range of 5 to 20% by weight based on the rosin-based substance of the present invention, that is, the mixture of the reinforced rosin and the phenolic resin. Considering the size effect and foaming properties, the amount used is optimally in the range of 10 to 15% by weight.

Since the alkali neutralized salt of the quaternary copolymer used in the present invention has excellent dispersing ability with respect to the rosin-based material, it is necessary to obtain an aqueous emulsion from the rosin-based material by the phase inversion method. It is not necessary to use surfactant-based dispersants known in the art. However, the present invention does not exclude the use of these known surfactant-based dispersants. Accordingly, polyoxyethylene sulfosuccinic acid half-ester salts of higher alcohols, alkyl phenols, alkyl aryl phenols or polystyrene phenols, polyoxyethylene sulfates of alkyl phenols, alkyl aryl phenols or polystyrene phenols, alkyl benzene sulfonates, α-
Surfactant-based dispersants such as olefin sulfonates can be used in the present invention, but the amount used can be in the range of 0.1 to 1.0% by weight based on the rosin-based material.

According to the method of the present invention, a mixture of a reinforced rosin and a phenolic resin corresponding to 5 to 20% by weight thereof is melted by heating, and the melt contains the alkali neutralized salt of the quaternary copolymer described above. The mixture is sufficiently stirred while the aqueous solution is added dropwise to prepare a homogeneous W / O emulsion. Then warm water was added to this emulsion under vigorous stirring to invert the phase, and the O / W
An aqueous emulsion of the type is prepared.

In this case, the total amount of the aqueous solution containing the dispersant is preferably in the range of 30 to 60% by weight of the melt. When the aqueous solution is dropped, the temperature of the melt is set at 20 degrees below its melting point.
It is preferable to maintain the temperature at a high temperature of at least 100 ° C. so that the temperature of the mixture at the end of the dropwise addition of the aqueous solution of the dispersant is about 100 ° C. Subsequently, the desired aqueous emulsion sizing agent is obtained by successively inverting the temperature of the mixture by dripping warm water at 90 to 95 ° C. with stirring.

[Operation] The rosin emulsion sizing agent obtained by the method of the present invention has low foaming properties and exhibits a good sizing effect. This is because the reinforced rosin is melted in the coexistence of the phenolic resin. In addition to the fact that the melt has improved affinity with water as compared with the case of reinforced rosin alone, and together with the strong dispersing ability of the alkali neutralized salt of the specific quaternary copolymer, a fine and homogeneous emulsion It is presumed that particles can be formed.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

Example Preparation of fortified rosin (A) 100 parts by weight of rosin are heated and melted, and the temperature is raised to 190 ° C. 11 parts by weight of fumaric acid was added thereto with stirring, and the mixture was reacted at 200 ° C. The reaction was completed when it was confirmed that substantially no unreacted fumaric acid was present. The acid value of the obtained fortified rosin (A) was 241 and the melting point was 100 ° C.

Production of quaternary copolymer alkali neutralized salt Emulsifier (polyoxyethylene polyoxypropylene block polymer, trade name: EPAN U-10) was added to 320 parts by weight of water.
3 Daiichi Kogyo Seiyaku Co., Ltd.) was dissolved in 5 parts by weight, and monomers were added thereto in the compounding ratio shown in Table 1. Further, 10 parts by weight of isopropylene alcohol and 3 parts by weight of 2-ethylhexyl thioglycolate were added. Is added and stirred. Next, 3 parts by weight of APS and 3 parts by weight of SBS were added, and the mixture was reacted at 75 to 80 ° C. for 5 hours to complete the polymerization, thereby obtaining a copolymer emulsion having a concentration of 27%.

Thereafter, 28% aqueous ammonia was added to this emulsion, and a neutralization reaction was performed for 1 hour. Then, water was added so that the concentration became 25%, and a copolymer having a degree of neutralization of 75 mol% was obtained. A solution of the alkali neutralized salt was obtained.

A phenolic resin was added to the reinforced rosin (A) produced in the above Preparation Example to make up to 100 parts by weight, and the mixture was heated to 160 ° C. and melted. Next, a 20% aqueous dispersant solution (component: polyoxyethylene sulfosuccinic acid half ester of nonylphenol)
Na salt) was added and mixed by 2.5 parts by weight. The internal temperature was maintained at 98 ° C. by refluxing water. While maintaining this temperature, 50 parts by weight of the dispersant A was added and mixed uniformly. Then 90 ° C
Was added to the mixture to invert the phase to obtain a 50% aqueous emulsion sizing agent having uniform and finely dispersed particles.

Comparative Example 1 An aqueous emulsion having a concentration of 50% by a phase inversion method using 100 parts by weight of reinforced rosin (A) and a 20% aqueous solution of sodium salt of polyoxyethylene sulfosuccinic acid half ester of nonylphenol without using a phenolic resin. A sizing agent was obtained.

Comparative Example 2 (Method of JP-A-61-108796) Preparation of fortified rosin (B) Reinforced rosin (B) in the same manner as the above-mentioned method for preparing a fortified rosin using 100 parts by weight of rosin and 10 parts by weight of fumaric acid
Was prepared.

Preparation of Copolymer Dispersant A monomer mixture consisting of 60 parts by weight of styrene, 25 parts by weight of acrylic acid and 15 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of dodecyl mercaptan, and polyoxyethylene (n = 10) nonylphenyl ether sulfate half 5 parts by weight of the ester and 3 parts by weight of ammonium persulfate were added to and mixed with 300 parts by weight of water, and emulsion polymerization was carried out at 80 ° C. for 4 hours.
Then, the mixture was cooled to 60 ° C.
Parts by weight and 30 parts by weight of water were gradually added dropwise, stirred for 30 minutes and then cooled to obtain a neutralized product having a ketone degree of 75%. Water was added thereto to obtain a dispersant X having a concentration of 25%.

Further, a dispersant Y having a concentration of 25% was obtained in the same formulation as above except that 25 parts by weight of methacrylic acid was used instead of 25 parts by weight of acrylic acid.

Using the thus obtained fortified rosin (B) and dispersants X and Y, an aqueous emulsion sizing agent having a concentration of 50% was obtained in the same manner as in the example.

The appearance, light transmittance, foamability and size effect of each emulsion sizing agent obtained in the above Examples and Comparative Examples were determined by the following methods. Table 2 shows the results regarding the appearance and the light transmittance, and Table 3 shows the results regarding the foamability and the size effect.

Appearance 50 cc of the sizing agent is collected in a 200 cc transparent glass bottle. After sealing, the bottle is inverted and allowed to stand, and the sizing agent flows down in a thin layer on the wall of the jar and is visually observed.

：: No coarse particles are present, and a clear feeling appears within 10 seconds.

：: No coarse particles are present, and transparency appears after 20 seconds.

Δ: Coarse particles are present, and a clear feeling appears after 20 seconds or more.

Light transmittance Solids concentration of sizing agent using deionized water
Dilute to 0.05% by weight and use a diffraction grating photoelectric colorimeter (Spectron
ic 20 manufactured by Shimadzu Corporation), the light transmittance at a wavelength of 560 nm was measured. The light transmittance of each sizing agent is represented by a relative value when the light transmittance of deionized water alone is set to 100%. The higher this value is, the finer the dispersed particle diameter of the sizing agent sample is.

Foaming test Pulp slurry with a concentration of 0.75% (pipe L-
80 ml of (BKP CSF 400 ml) is collected in a 100 ml measuring cylinder with a stopper, and 1 ml of a 1% band solution is added thereto and shaken 20 times. Next, 1 ml of a diluent for a sizing agent having a solid content of 1% is added, and the mixture is shaken up and down 20 more times. After that, the sample is allowed to stand still and the amount of floating species generated after 5 minutes has elapsed is measured. The higher the numerical value, the greater the foamability.

Size effect test 20% talc and 0.2% emulsion sizing agent are added to the pulp slurry of L-BKP (CSF 400ml) at a concentration of 2.4% with respect to the weight of the dry bone pulp and mixed well. The bands were mixed (see Table 2) to form a prepared pulp slurry. Next, TA
Hand-punched with PPI standard sheet machine, press pressure 3.5Kg / cm ²
And then dried for 1 minute with a drum dryer (surface temperature 90 ° C.) to prepare a hand-made paper. The resulting handmade paper is
It was equivalent to 60 g / m ^2, and after conditioning, the degree of Stigecht sizing was measured according to JIS P-8122.

[Effects] As is clear from the above description, the rosin-based emulsion sizing agent obtained by the method of the present invention has a very fine and stable dispersion of size particles and a small content of a dispersing agent. There is a feature that foaming is extremely small at the time of addition to the slurry, and the size effect is also good. Therefore, the present invention has a high industrial value as a method for producing a sizing agent capable of solving troubles caused by the sizing agent accompanying deterioration of water used in the papermaking process.

Claims (3)

(57) [Claims] A rosin-based material in a molten state and water containing a dispersant are mixed to form a dispersion in which the rosin-based material is a continuous phase and water is a dispersed phase. In the method for producing a rosin-based emulsion sizing agent, which obtains an aqueous emulsion in which water is a continuous phase and a rosin-based substance is a dispersed phase by adding and reversing the phase, a phenolic resin is used as the rosin-based substance. And a mixture of reinforced rosin and a quaternary copolymer of a styrene-based monomer, acrylate, acrylic acid, and methacrylic acid as the dispersant. Manufacturing method of emulsion sizing agent. 2. The method according to claim 1, wherein the amount of the alkali neutralized salt of the quaternary copolymer is in the range of 5 to 20% by weight of the rosin-based substance. 3. The quaternary copolymer has a molecular weight of 2,000 to 1,500.
3. The method according to claim 2, which is prepared by an emulsion polymerization method using 0 polyoxyethylene polyoxypropylene as an emulsifier.