JP2876136B2 - Method for producing cationic rosin emulsion sizing agent - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a novel and useful cationic rosin emulsion sizing agent, which comprises anionic rosin emulsion in the presence of a modified (meth) acrylamide polymer. By mixing a rosin emulsion with a vinyl copolymerizable cationic polymer and / or a cationized starch, a cationic rosin emulsion sizing agent having excellent storage stability is provided.

[Prior art] In the papermaking industry, there are issues such as improving paper quality, closing papermaking systems, and using waste paper and waste paper containing calcium carbonate as a pulp raw material. The tendency to make paper in the neutral region with a reduced rate is increasing. However, when a conventional rosin-based sizing agent, particularly a solution rosin sizing agent that is an alkali neutralized product of fortified rosin, is used, if the papermaking pH is increased by reducing the rate of addition of the bansulfate, the size effect is rapidly reduced. In particular, when calcium carbonate is mixed in the papermaking system, the tendency becomes remarkable. As a countermeasure, a larger amount of bansulfate had to be added, and as a result, there were problems in paper quality, operation and cost. Also,
Superior in size effect than solution type rosin sizing agent, applicable pH
Even when using a wider range of anionic rosin emulsion sizing agent (enhanced rosin dispersed as fine particles in water using an anionic emulsifying dispersant),
Although the addition rate of bansulfate could be reduced as compared with solution rosin, reduction and fluctuation of the size effect in the neutral pH range were inevitable and not satisfactory. Under these circumstances, there is a strong demand for a rosin-based sizing agent that exhibits a low sulphate addition rate and exhibits an excellent sizing effect even in a pH range close to neutrality.

Cationic rosin emulsion sizing agents have attracted attention as sizing agents that can meet this demand. Rosin emulsion sizing agent with cationic properties has self-fixing property to pulp fiber, can reduce the amount of bansulfate required for sizing effect, and exhibits excellent sizing effect even in neutral pH range (TAPPI Papermakers Conference 1988 pp.181-18
8). However, cationic rosin emulsions are more difficult to produce industrially than anionic ones that have been commonly used in the past, and still have problems in terms of static stability and performance of the products. Improvements are required.

Although there are some prior arts relating to cationic rosin emulsion sizing agents, they are roughly classified into two production methods. One method is to emulsify a water-insoluble rosin-based substance using a cationic emulsifying dispersant, and the other method is to mix a cationic substance with an anionic rosin emulsion and convert it to a cationic emulsion. It is.

The former is disclosed in Japanese Patent Publication No. 58-34509 (Japanese Unexamined Patent Publication No.
-36703, U.S. Pat. No. 3,966,654), in which the reinforced rosin is dispersed with a water-soluble cationic resin dispersant such as polyaminopolyamide-epichlorohydrin resin, alkylenepolyamine-epichlorohydrin resin, poly (diallylamine) -epichlorohydrin resin. A method for dispersing is described. In this method, reinforced rosin insoluble in water is directly emulsified and dispersed with a cationic resin dispersant using a homogenizer or the like. However, the emulsifying and dispersing function of these cationic resins with respect to rosin-based substances is not sufficient, so that there is a problem in storage stability as mentioned in JP-A-53-27649. In addition, the content of the cationic resin in the emulsion must be increased, which causes a problem that the cost of the product is high and that the papermaking system using the product has a lot of foaming.

On the other hand, as the latter prior art, British Patent No. 2141751A
And British Patent No. 2159183A, including commonly used anionic rosin emulsions and positively charged organic polyelectrolytes (preferably polydi (lower alkyl) diallyl quaternary ammonium chloride) or inorganic cationic polymers (Preferably aluminum polyhydroxy chloride) using a high speed mixer and described as being used as a "One shot" sizing composition. According to these methods, `` When a rosin emulsion and a cationic substance are mixed, aggregation occurs first, but if further stirring is performed, a stable product can be obtained for a few weeks, and even if separation occurs, it can be redispersed by stirring. "Is a very unstable dispersion consisting essentially of non-uniform aggregated particles.

[Problem to be Solved by the Invention] As described above, the conventional cationic rosin emulsion sizing agent has a problem in storage stability, and its improvement has been desired.

Therefore, the present invention provides a method for producing a cationic rosin emulsion sizing agent which has excellent storage stability, exhibits an excellent sizing effect even at a papermaking pH near neutrality, and can be easily produced on an industrial scale. Is what you do.

Means for Solving the Problems The present inventors have conducted intensive studies on a method for producing a cationic rosin emulsion, and as a result, a commercially available anionic rosin emulsion was converted to a vinyl rosin emulsion in the presence of a (meth) acrylamide polymer. By performing a mixing treatment with a copolymerizable cationic polymer and / or a cationized starch, anionic particles can be converted to cationic without any aggregation of emulsion particles, and a cationic rosin emulsion having excellent storage stability can be obtained. And completed the present invention.

That is, the present invention provides: (a) a rosin emulsion having anionic property; (b) an acrylamide-based polymer and / or a methacrylamide-based polymer; and (c) a vinyl-based copolymerizable cationic polymer obtained by copolymerizing a cationic monomer in an amount of 12 mol% or more. The polymer and / or the cationized starch, when used alone, contains the cationized starch obtained by reacting 0.25 mol or more of a cationizing agent per 1 mol of anhydrous glucose of the starch, wherein the (b) A) a cationic rosin which mixes and disperses the above component (a) in the presence of the component, then mixes and disperses the above component (c), and converts the anionic rosin emulsion of the component (a) into a stable cationic rosin emulsion; The present invention provides a method for producing an emulsion sizing agent.

At this time, the component (b) is (b-1) 10 mol% or less of a cationic monomer (b-2) 5 mol% or less of an anionic monomer (b-3) 15 mol% or less of a hydrophobic monomer (b-4) A monomer comprising at least 70 mol% of acrylamide and / or methacrylamide is converted to (b-) in the presence of an alkyl mercaptan having 6 to 22 carbon atoms of 10 mol% or less based on all monomers.
3) A polymer obtained by polymerizing one or both of a hydrophobic monomer and an alkyl mercaptan in a total amount of 0.01 mol% or more.

 Next, the present invention will be described in detail.

When a cationic substance is directly mixed with a rosin emulsion exhibiting anionic property, severe aggregation of the emulsion particles generally occurs, and the rosin emulsion cannot exist as a safe emulsion (dispersion). Like the "One Shot" sizing composition described above, it is possible to temporarily disperse the aggregated emulsion particles by vigorous stirring, but it cannot be said to be a stable emulsion and has good storage stability and constant It is difficult to obtain a size effect.

On the other hand, several methods have been found to convert anionic emulsions, latexes and dispersions to cationic. For example, a method in which an anionic latex is added to an excessive amount of a polyelectrolyte solution (polyvinylbenzyltrimethylammonium salt) under vigorous stirring (US Pat.
3205187), a method of mixing an anionic latex with an amphoteric emulsifier and then adding a cationic emulsifier (JP-A-60-1985)
No. 152537) and anionic emulsions
After adding an amine-based stabilizer and an anionic dispersant having a cationic property at 6.5 or less, the pH of the emulsion is adjusted to 6.
There is a method of reducing the number to 5 or less (JP-A-64-34434). However, a conversion method using a combination of a (meth) acrylamide-based polymer and a vinyl-based copolymerizable cationic polymer and / or a cationized starch as in the present application has not been found in the past.

Among the prior arts relating to rosin emulsion sizing agents, there are those relating to cationic rosin emulsion sizing agents using the above-mentioned water-soluble cationic resin (polyaminopolyamide-epichlorohydrin resin or the like) as a dispersant (Japanese Patent Laid-Open No. 50-36703). Japanese Patent Application Laid-Open No. 56-169898) and a rosin emulsion sizing agent containing a modified polyacrylamide resin (JP-A-56-169898), but an anionic rosin emulsion and a (meth) acrylamide-based polymer, No description can be found for a method for producing a stable cationic rosin emulsion sizing agent comprising a copolymerized cationic polymer and / or a cationized starch.

The (a) anionic rosin emulsion sizing agent in the present invention is obtained by emulsifying and dispersing a rosin-based substance using an anionic surfactant or an anionic polymer dispersant, and generally commercially available products can be used. It is. Properties such as size performance and mechanical stability of the anionic rosin emulsion, and especially the particle state such as particle size distribution, affect the performance of the cationic emulsion as the final product. It is desirable to use one having a narrow particle size distribution and good properties.

The (b) acrylamide-based polymer and / or methacrylamide-based polymer of the present invention comprises (b-1) a cationic monomer as a monomer component in an amount of 0 to 10 mol%, preferably 0 to 7 mol%, and (b-2) an anionic monomer. 0 to
5 mol%, preferably 0 to 3 mol%, (b-3) 0 to 15 mol%, preferably 0 to 10 mol%, and (b-4) one or both of acrylamide and methacrylamide The mixture contains 70 to 100 mol%, preferably 80 to 100 mol%, and has a
It is obtained by polymerizing or copolymerizing the above monomers in the presence of 0 mol%, preferably 0.01 to 5 mol%, of alkyl mercaptan having 6 to 22 carbon atoms. However, (b-3)
At least 0.01 mol% in total of one or both of the hydrophobic monomer and the alkyl mercaptan is necessarily contained.

When the composition ratio of the monomer component of the polymer (b) is outside the above range, the cationic rosin emulsion obtained tends to cause aggregation or thickening (creaming) of the particles. Further, the polymer is a weak anion
It is preferable to have a charge in the range of a weak cation, and this can be realized by combining any one or both of the (b-1) cationic and (b-2) anionic monomers within the above monomer composition ratio. .

Examples of the (b-1) cationic monomer include (mono- or di-alkyl) amino (hydroxy) alkyl (meth) acrylate, (mono- or di-alkyl) aminoalkyl (meth) acrylamide, vinylpyridine, and vinylimidazole , Diallylamine and the like, and furthermore, quaternary ammonium salts thereof. These may be used alone or in combination of two or more.

(B-2) Examples of the anionic monomer include (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid,
Monomers having a carboxylic acid group such as citraconic acid and crotonic acid, monomers having a sulfonic acid group such as vinylsulfonic acid, (meth) allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and sulfonated styrene, or hydroxyalkyl Monomers having a phosphoric ester group such as a phosphoric ester of (meth) acrylate can be mentioned, and they can be used alone or in combination of two or more.

The (b-3) hydrophobic monomer and alkyl mercaptan are for imparting hydrophobicity to the polymer of (b), and at least one or both of them are required to be 0.01 mol% or more in total. Component. Both are not contained or the total of both is 0.01
When a polymer containing less than mol% was used, the resulting cationic emulsion was inferior in safety, and a tendency of aggregation and thickening of particles was observed. It is not clear why these hydrophobicity-imparting moieties contribute to safety, but the presence of an appropriate amount of hydrophobic groups in the polymer molecule or at the end enhances the adsorptivity to emulsion particles, further stabilizing the particles. It is supposed to do.

Examples of the hydrophobic monomer (b-3) include styrene or a derivative thereof, alkyl (meth) acrylate, vinyl esters such as vinyl acetate and vinyl propionate, and methyl vinyl ether. Two or more can be used in combination. The monomer was added to 15
Use of more than mol% is not preferable because the resulting emulsion is unsafe or the amount of the (meth) acrylamide-based polymer becomes too large for stabilization, resulting in a decrease in size performance.

As the alkyl mercaptan having 6 to 22 carbon atoms, the alkyl group may be linear or branched, and the raw material of the alkyl group may be a natural one or an artificial one such as cracking of low-polymerized paraffin such as ethylene or propylene. Any of those manufactured may be used. For example, normal octyl mercaptan, tertiary dodecyl mercaptan, normal dodecyl mercaptan, normal octadecyl mercaptan, or normal
Hexadecyl mercaptan and the like can be mentioned, and one kind or a mixture of two or more kinds can be used.

Of these, normal-octyl mercaptan and normal-dodecyl mercaptan are preferred. Even if the alkyl mercaptan is used in an amount of more than 10 mol% based on all monomers, not only does it not contribute to the stability of the emulsion, but also the amount of alkyl mercaptan that is not introduced into the polymer during the polymerization reaction increases, and the stability and size effect of the emulsion also increase. This may have adverse effects and is not economically favorable. The alkyl mercaptan not only functions to introduce a hydrophobic group into the polymer as described above, but also plays a role of regulating the molecular weight of the polymer as a chain transfer agent.

As the method for synthesizing the (b) (meth) acrylamide-based polymer, a conventionally known method can be applied. For example, in the presence of an alkyl mercaptan having 6 to 22 carbon atoms, (b-
The monomers 1) to (b-4) are polymerized with a radical polymerization catalyst in a lower alcohol such as methyl alcohol, ethyl alcohol or isopropyl alcohol, or in a mixture of these lower alcohols or water. By distillation. Examples of the radical polymerization catalyst include persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate; a redox polymerization catalyst obtained by combining these persulfates with a reducing agent; or 2,2′-azobisisobutyronitrile. And the like. If necessary, a known chain transfer agent may be appropriately used in combination.

The viscosity of the polymer solution (b) thus obtained is 10 to 5,000 centipoise in a 20% by weight aqueous solution (however,
(Measured at 25 ° C. at 60 revolutions per minute by a Brookfield viscometer) is preferable.
More preferred are those of ~ 1000 centipoise. When the viscosity is out of the above range, the miscibility with an anionic emulsion and the stability of a cationic emulsion sizing agent prepared using the same tend to be poor.

The polymer (b) is required to be 2% by weight or more based on the solid content of the anionic emulsion (a). A range of about 10% by weight is preferred.

The vinyl copolymerizable cationic polymer of the component (c) of the present invention includes, for example, (mono or dialkyl) amino (hydroxyl) alkyl (meth) acrylate, (mono or dialkyl) aminoalkyl (meth) acrylamide, vinylpyridine, vinyl A cationic water-soluble synthetic polymer containing imidazole, diallylamine, etc. or a quaternary ammonium salt alone or as a mixture of two or more as a cationic monomer and containing at least 12 mol%. , 5 to 2000 centipoise.

As the cationized starch of the component (c) of the present invention, for example, raw starch such as potato starch, corn starch, tapioca starch, wheat starch, or the raw starch is oxidized with mineral acid, sodium hypochlorite, hydrogen peroxide or the like. The processed starch which has been cationized with a cationizing agent can be used.

Means of cationization include, for example, 3-chloro-2 in the presence of an alkali metal or alkaline earth metal hydroxide, or an alkali substance such as quaternary ammonium hydroxide.
A method of reacting starch with a cationizing agent such as -hydroxypropyltrimethylammonium chloride, glycidyltrimethylammonium chloride, or diethylaminoethyl chloride. The degree of cationization is
From the viewpoint of storage stability and size performance of the obtained cationic rosin emulsion, the cationic group is preferably 0.01 mol or more, more preferably 0.1 mol, per mol of anhydrous glucose of starch.
When the cationized starch is used alone, the cationic group is at least 0.25 mol. Further, in order to increase the stability of the obtained cationic rosin emulsion, in addition to the cationization reaction of starch, for example, etherification,
Starches and the like whose viscosity has been reduced by an esterification reaction or heat treatment in the presence of an acid can also be used.

The amount of the vinyl copolymerizable cationic polymer and / or cationized starch of the component (c) depends on the anionicity of the anionic rosin emulsion and the ionicity of the (meth) acrylamide polymer of (b). It is sufficient that the amount of the emulsion can be essentially converted to cationic, but from the viewpoint of economy, the solid content is preferably 5 to 20% by weight based on the solid content of the anionic rosin emulsion.

The mixing method for producing the cationic rosin emulsion of the present invention comprises: (b) adding (a) an anionic rosin emulsion to a (meth) acrylamide-based polymer under gentle stirring; A method of adding a system copolymerizable cationic polymer and / or a cationized starch is used.

The cationic rosin emulsion sizing agent of the present invention thus obtained is not only easier to produce than conventional methods, but also anionic rosin emulsion particles,
By interposing a (meth) acrylamide-based polymer, particle aggregation hardly occurs, and the polymer is efficiently cationized with a vinyl-based copolymerizable cationic polymer and / or a cationized starch. Excellent safety. In addition to the acidic papermaking system, especially in the neutral papermaking system, in addition to exhibiting an excellent sizing effect not found in conventional sizing agents, the papermaking system also has the advantage of less foaming. I have.

[Examples] Next, the present invention will be specifically described with reference to examples. In addition,
"Parts" indicates parts by weight, and% indicates% by weight.

Production of anionic rosin emulsion -1 Production of fumaric acid enriched rosin 7 parts of fumaric acid is gradually added to 46 parts of gum rosin in a molten state at about 200 ° C., and after almost all of the fumaric acid has been reacted. Further, 47 parts of formaldehyde-treated (modification ratio: 3%) tall oil rosin were added, and the mixture was melt-stirred and homogenized, and then the reaction product was cooled to room temperature. The reaction product (enhanced rosin) was rosin to which 7% of fumaric acid was added.

-2 Production of rosin emulsion rosin emulsion (A-1) to
(A-3) was obtained.

Emulsion (A-1) As a typical example of a rosin emulsion using an anionic polymer dispersant, a saponified styrene-methacrylic acid-based copolymer of Reference Example 8 of JP-A-61-108795 is used. According to Example 3, anionic rosin emulsion (A
-1) was obtained.

That is, 250 parts of the fumaric acid-reinforced rosin obtained in -1 was heated and melted at about 150 ° C., and while vigorously stirring, the saponified styrene-methacrylic acid copolymer 13 of Reference Example 8 of the above publication was used.
5 parts and 7 parts of ammonium salt of 20% polyoxyethylene (degree of polymerization 12) dodecylphenyl ether sulfate were added and mixed to obtain a water-in-oil emulsion. Hot water was gradually added to this to invert the phase to form an oil-in-water emulsion. Hot water was added quickly to form a stable oil-in-water emulsion, and then cooled to room temperature. The total of hot water used for phase inversion and dilution was 211 parts, and the emulsion (A-1) thus obtained contained about 45% of solids, and about 0.5% of the solids contained the above anionic surfactant. Agent
7.5% was a saponified styrene-methacrylic acid copolymer, which was stable for a long time.

Emulsion of (A-2) A representative example of an anionic rosin emulsion using an anionic low molecular surfactant was obtained by the following method.

250 parts of the fumaric acid-enriched rosin obtained in -1 were heated and melted at about 150 ° C., and a small amount of water was added.
50% of an ammonium salt of 0% polyoxyethylene (degree of polymerization: 12) octyl phenyl ether sulfate was added and mixed to obtain a water-in-oil emulsion. Hot water was gradually added to this to invert the phase to form an oil-in-water emulsion. Hot water was added quickly to form a stable oil-in-water emulsion, and then cooled to room temperature. The total of hot water used for phase inversion and dilution was 220 parts.

The emulsion (A-2) obtained here contained about 50% solids and was stable for a long time.

(A-3) Emulsion A typical example of an anionic rosin emulsion using casein as a dispersant was obtained by the following method with reference to JP-A-63-288297.

-1 350 parts of fumaric acid-enriched rosin obtained in -1 was heated and melted at about 150 ° C., a small amount of water was added, and the temperature was lowered to about 130 ° C.
A 15% aqueous casein solution containing 17 parts of casein, 3.5 parts of potassium hydroxide, and 4 parts of sodium tetraborate was added to obtain a water-in-oil emulsion. Hot water was gradually added to this to invert the phase to form an oil-in-water emulsion. Hot water was added quickly to form a stable oil-in-water emulsion, and then cooled to room temperature.

The emulsion (A-3) obtained here contained about 50% solids and was stable for a long time.

Production of (meth) acrylamide-based polymer (meth) of (B-1)-(B-9) as follows
An acrylamide polymer was produced.

Aqueous polymer solution of (B-1) 9.4 parts of dimethylaminoethyl methacrylate, 50% aqueous solution of acrylamide 131 in a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube
Parts, 1.4 parts of acrylic acid, 107.6 parts of ion-exchanged water, 134.6 parts of isopropyl alcohol, and 0.8 part of normal-dodecyl mercaptan, and adjusted to pH 4 with a 20% aqueous sulfuric acid solution. While stirring this mixed solution under a nitrogen gas atmosphere, 60
The temperature was raised to ° C. As a polymerization initiator, 2.3 parts of a 5% aqueous solution of ammonium persulfate was added, and the temperature was raised to 78 ° C. and maintained for 1.5 hours. Then, 0.7 part of a 5% aqueous solution of ammonium persulfate was added. Further, after maintaining at the same temperature for one hour, ion-exchanged water
200 parts were added and isopropyl alcohol was distilled off.

After completion of the distillation, the solid content concentration of the polymer solution (B-1) obtained by adding ion-exchanged water was 20.3%, Brookfield viscosity measured at 25 ° C. and 60 revolutions per minute (hereinafter referred to as viscosity).
Was 410 centipoise (cps). The solid content, viscosity, etc. are shown in Table 1.

Aqueous solution of polymer of (B-2) to (B-9) A method for producing the polymer of the above (B-1), except that the monomer composition shown in Table 1 was used and the ratio of isopropyl alcohol to water was appropriately changed for viscosity control. In the same manner as in (1), polymer aqueous solutions (B-2) to (B-9) were obtained. The solid content, viscosity, etc. are shown in Table 1.

Production Example of Vinyl Copolymer Cationic Polymer and Cationized Starch Vinyl Copolymer Cationic Polymers (C-1) to (C-3) and cationized starch (C-4, C
-5) was manufactured.

(C-1) Vinyl Copolymerization Cationic Polymer In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, dimethylaminopropylacrylamide methyl chloride quaternized product 41 was added. Parts, 50 parts of 50% aqueous solution of acrylamide, 150 parts of ion-exchanged water,
161 parts of isopropyl alcohol and 1 part of normal-dodecyl mercaptan were charged and adjusted to pH 4 with a 20% aqueous sulfuric acid solution. The mixture was heated to 60 ° C. under a nitrogen gas atmosphere while stirring. As a polymerization initiator, 2.3 parts of a 5% aqueous solution of ammonium persulfate was added, and the temperature was raised to 78 ° C. and maintained for 1.5 hours. Then, 0.7 part of a 5% aqueous solution of ammonium persulfate was added.

Further, after maintaining at the same temperature for one hour,
0 parts were added, and isopropyl alcohol was distilled off.
After the distillation was completed, ion-exchanged water was added, and the resulting polymer solution had a solid content of 20% and a viscosity of 235 centipoise.

(C-2) 61.5 parts of dimethylaminopropylacrylamide methyl chloride quaternary compound in the same reactor as the vinyl copolymerizable cationic polymer (C-1),
85.3 parts of a 50% aqueous solution of acrylamide, 208.
8 parts, 195.6 parts of isopropyl alcohol and 1 part of normal-dodecyl mercaptan were charged, and a 20% aqueous sulfuric acid solution was used.
Adjusted to pH4. The mixture was heated to 60 ° C. under a nitrogen gas atmosphere while stirring. 2.3 parts of a 5% aqueous solution of ammonium persulfate was added as a polymerization initiator, and the temperature was raised to 78 ° C.
After holding for 5 hours, a 5% aqueous solution of ammonium persulfate 0.7
Added a section.

Further, after maintaining at the same temperature for one hour,
0 parts were added and isopropyl alcohol was distilled off. After the distillation was completed, ion-exchanged water was added, and the resulting polymer solution had a solid content of 20% and a viscosity of 260 centipoise.

(C-3) Vinyl copolymerizable cationic polymer (for comparative example) 8.5 parts of dimethylaminopropylacrylamide methyl chloride quaternary product in the same reactor as (C-1),
135.1 parts of a 50% aqueous solution of acrylamide, ion-exchanged water 10
5.8 parts, 134.8 parts of isopropyl alcohol, and 1 part of normal-dodecyl mercaptan were charged and adjusted to pH 4 with a 20% aqueous sulfuric acid solution. The mixture was heated to 60 ° C. under a nitrogen gas atmosphere while stirring. As a polymerization initiator, 2.3 parts of a 5% aqueous solution of ammonium persulfate was added, and the temperature was raised to 78 ° C. and maintained for 1.5 hours. Then, 0.7 part of a 5% aqueous solution of ammonium persulfate was added. After maintaining the same temperature for one hour, 200 parts of ion-exchanged water was added to distill off isopropyl alcohol. After the distillation was completed, ion-exchanged water was added, and the resulting polymer solution had a solid content of 20% and a viscosity of 320 centipoise.

Production Example of Cationized Starch of (C-4) 100 parts of hydrogen peroxide-treated corn starch was added to 285 parts of water, and the mixture was stirred at 85 ° C for 1 hour. Next, the temperature was lowered to 60 ° C. or lower, 1.7 parts of sodium hydroxide and 40.5 parts of glycidyltrimethylammonium chloride were added, and the mixture was stirred for 4.5 hours. Thereafter, the temperature was lowered to 30 ° C. or lower, and 181 parts of water and 1.8 parts of 98% sulfuric acid were added. The obtained modified starch solution had a solid content of 20% and a viscosity of 360 centipoise at 25 ° C.

Production Example of (C-5) Cationized Starch The cationized starch solution obtained in (C-4) was treated with sulfuric acid.
The mixture was adjusted to pH 3 and heat-treated at 80 ° C. for 2 hours. The resulting solution had a solids concentration of 20% and a viscosity of 26 centipoise at 25 ° C.

Production of Cationic Rosin Emulsion Sizing Agent -1 Examples Examples 1 to 8 A predetermined (meth) acrylamide polymer and water were mixed in a mixing ratio (solid content weight ratio) as shown in Table 2 in a flask equipped with a stirrer. The charged, anionic rosin emulsion was added with stirring, then the vinyl copolymerizable cationic polymer and cationized starch were added, and the mixture was stirred for about 10 minutes to obtain a cationic rosin emulsion sizing agent.

The obtained sizing agents are all cationic as is clear from the values of the zeta potential shown in Table 2, show little aggregation by visual observation and average particle size, and are stable cationic rosin emulsion sizing agents. Met.

The measurement of zeta potential, a sizing agent samples ^10-3
M Dilute to 0.01% with potassium chloride solution, p with caustic potash
After adjusting to H7, it was measured with a zetameter (Lazer-Zee Meter, manufactured by Penchem) and indicated in mV.

In addition, the average particle size is 0.2%
And then measured with Master Sizer (Malvern),
The value was expressed in μm.

-2 Comparative Examples Comparative Examples 1 to 8 Sizing agents were prepared in the same manner as in Examples 1 to 8 at the compounding ratios shown in Table 2. However, Comparative Examples 6 to 8 are (meta)
No acrylamide polymer was used. Comparative Example 5
Other than that, solidification occurred or did not solidify, but contained a large amount of aggregates. As a result, the average particle diameter was large and storage stability was poor.

Comparative Example 9 According to Example 1 of US Pat. No. 3,966,654, an emulsion was obtained as follows.

300 parts of the fumaric acid-enriched rosin of the above -1 is dissolved in 300 parts of benzene, and 400 parts (solid content: 50 parts) of the aminopolyamide epichlorohydrin resin solution prepared in Reference Example 17 of the above-mentioned U.S. Pat. Mixed. The mixture was passed twice through an industrial homogenizer at a pressure of about 150 Kg / cm ² , after which all benzene was removed by vacuum distillation. The resulting rosin emulsion has about 35% solids, of which about 85% is fortified rosin and about 15%
% Was aminopolyamide epichlorohydrin resin.

Comparative Example 10 35% (solid content) without adding (meth) acrylamide-based polymer and cationic epichlorohydrin-based resin
Diluted to a concentration.

Table 2 shows the compositions and properties of the sizing agents of the above Examples and Comparative Examples.

Using each of the sizing agents prepared in the above Examples and Comparative Examples, a size effect, a standing stability and a foaming test were conducted. The test conditions are shown below.

Size effect test Bleached kraft pulp (mixed pulp with a softwood to hardwood pulp ratio of 1: 4) is diluted to a pulp concentration of 2.5% with dilution water of hardness 100 ppm and heated to 350 ml Canadian standard freeness using a heater. did.

Next, the pulp slurry 1.2 was weighed into a disintegrator, and a sizing agent having a pulp weight of 0.5% (solids weight ratio) and a pulp slurry of 0.2%
Simultaneously add 5% (solid content weight ratio) bansulfate
The pH was adjusted to a value of 7 by stirring afterwards for 30 minutes.
Then, this pulp slurry is diluted to a concentration of 0.25% with dilution water of pH7.
The mixture was diluted with a cationic polyacrylamide polymer as a fixing agent, and 0.05% of pulp (by weight based on solid content) was added thereto.

The obtained wet paper was pressed to a solid content of 40%, and then dried at 100 ° C. for 60 seconds with a drum dryer.
The paper thus obtained was conditioned in a constant temperature and humidity (20 ° C-60% relative humidity) environment for 24 hours to prepare a test paper material (basis weight 65g /
m ^2). The degree of size was measured by the Steckicht method. Table 3 shows the results
Shown in

Foaming test Using the same pulp slurry as in the above papermaking test, similarly, a sizing agent of 0.5% to pulp (solid content weight ratio) and a pulp of 0.25
% (Solid content weight ratio) of bansulfate was added at the same time, and the pH was adjusted to 7 with sodium hydroxide. After stirring for 3 minutes, this pulp slurry was diluted to 0.25% with water for dilution at pH 7, and a cationic acrylamide polymer as a fixing agent was added to the pulp at 0.05% (solids weight ratio). After stirring for 1 minute,
A part of the pulp slurry was put into a cylindrical container, circulated by a pump, and dropped from a height of about 1 m into the container.
The area of foam accumulated on the liquid surface after minutes was determined, and the accumulated foam area relative to the entire liquid surface was expressed as a percentage.

Stationary stability test A 100 cc sample of a sizing agent was placed in a test tube having a length of 30 cm and an inner diameter of 2.1 cm, allowed to stand for one month, and the height (mm) of the precipitate deposited at the bottom was measured.

In addition, when the vinyl copolymerizable cationic polymer and the cationized starch are used in combination as the component (C), at least the same effect as when the above is used alone can be obtained.

[Effects of the Invention] According to the present invention, an anionic property is obtained in the presence of an acrylamide-based polymer and / or a methacrylamide-based polymer having a predetermined monomer composition and obtained under predetermined conditions using a predetermined alkylmercaptan. The rosin emulsion is mixed and dispersed.
By mixing and dispersing a vinyl copolymerizable cationic polymer and / or cationized starch copolymerized in an amount of at least mol%, the above-mentioned anionic rosin emulsion was converted into a stable cationic rosin emulsion. Not only is production easier than in the production method described above, but also the anionic rosin emulsion particles hardly cause particle aggregation by interposing an acrylamide-based polymer and / or a methacrylamide-based polymer, and the vinyl-based copolymerized cation Since it is efficiently cationized by the hydrophilic polymer and / or the cationized starch, it has excellent storage stability and mechanical stability. In addition to the acidic papermaking system, especially in the neutral papermaking system, it has an excellent sizing effect not found in the conventional sizing agent, and has the advantage that the foaming of the papermaking system is small. Is

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsunori Nakamura 17-2 Yawata Kaigan-dori, Ichihara-shi, Chiba Inside Dick Hercules Co., Ltd. (72) Inventor Mizuchi Takahashi 17-Yawata Kaigan-dori, Ichihara-shi, Chiba 2 Inside Dick Hercules Co., Ltd. (72) Inventor Yasuko Sakawa 17-17 Yawata Kaigan-dori, Ichihara-shi, Chiba 2 Inside Dick Hercules Co., Ltd. (72) Inventor Mariko Shinohara Yawata-coast, Ichihara-shi, Chiba No. 17-2, Dick Hercules Co., Ltd. Laboratory (56) References JP-A-56-169898 (JP, A) JP-A-63-120198 (JP, A) JP-A-64-56135 (JP, A) (58) Fields surveyed (Int. Cl. ⁶ , DB name) D21H 3/28, 3/34, 3/38

Claims (3)

(57) [Claims] (1) a rosin emulsion having an anionic property; (b) an acrylamide polymer and / or a methacrylamide polymer; and (c) a vinyl copolymerizable cationic polymer obtained by copolymerizing a cationic monomer in an amount of 12 mol% or more. And / or a cationized starch, which, when used alone, contains a cationized starch obtained by reacting 0.25 mol or more of a cationizing agent with respect to 1 mol of anhydrous glucose of the starch. With respect to the above, the component (a) is mixed and dispersed in the presence of the component (b), the component (c) is mixed and dispersed, and the anionic rosin emulsion of the component (a) is converted into a stable cationic rosin emulsion. A method for producing a cationic rosin emulsion sizing agent to be converted, wherein the component (b) is (b-1) a cationic monomer (B-2) 5 mol% or less of anionic monomer (b-3) 15 mol% or less of hydrophobic monomer (b-4) acrylamide and / or methacrylamide
A monomer comprising 70 mol% or more of the above (b-3) in the presence of 10 mol% or less of an alkyl mercaptan having 6 to 22 carbon atoms based on the total amount of the hydrophobic monomer and one or both of the alkyl mercaptan and the alkyl mercaptan A method for producing a cationic rosin emulsion sizing agent, characterized in that the polymer is polymerized by incorporating 0.01 mol% or more of the above. 2. The cationic polymer according to claim 1, wherein the monomer of each of (b-1), (b-2) and (b-3) or any two or all of the components is zero. A method for producing a rosin emulsion sizing agent. 3. The method for producing a cationic rosin emulsion sizing agent according to claim 1, wherein the alkyl mercaptan is 0.