JPH03174092A - Sizing agent composed of cationic rosin emulsion and production thereof - Google Patents

Abstract

PURPOSE:To easily and industrially produce the subject sizing agent having excellent storage stability and exhibiting excellent sizing effect even under nearly neutral paper-making pH condition by mixing and dispersing an anionic rosin emulsion and a cationized starch, etc., in the presence of a specific polymer. CONSTITUTION:The objective sizing agent contains (A) a (meth)acrylamide polymer, (B) an anionic rosin emulsion and (C) a cationic substance composed of (i) a vinyl-copolymerized cationic polymer and/or (ii) a cationized starch. The agent can be produced by mixing and dispersing the components B and C in the presence of the component A, thereby converting the component B into a stable cationic rosin emulsion. In the case of singly using the component (ii), the cationic substance C is a reaction product produced by reacting >=0.25mol of a cationizing agent to 1mol of glucose anhydride unit of the starch.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a new and useful cationic rosin emulsion sizing agent and a method for producing the same. By mixing a rosin emulsion with a vinyl copolymerizable cationic polymer and/or a cationized starch, a cationic rosin emulsion sizing agent with excellent storage stability is provided.

[Conventional technology] The paper manufacturing industry is facing issues such as improving paper quality, closing the papermaking system, and using waste paper and waste paper containing calcium carbonate as pulp raw materials.As a countermeasure, the addition of sulfuric acid bread soil There is a growing tendency to perform papermaking in the neutral range with reduced yield. However, when using conventional rosin-based sizing agents, especially solution rosin sizing agents that are alkali-neutralized products of reinforced rosin, when the addition rate of sulfuric acid clay is reduced and the paper pH is increased, the sizing effect decreases rapidly. This tendency becomes particularly pronounced when calcium carbonate is mixed into the papermaking system. As a countermeasure, it was necessary to add a larger amount of sulfuric acid bread soil, which resulted in a decrease in paper quality and problems in terms of operation and cost. Also,
Superior sizing effect than solution-type rosin sizing agent, suitable for application
Even when using an anionic rosin emulsion sizing agent with a wider H range (strengthened rosin dispersed as fine particles in water using an anionic emulsifying dispersant), the addition of sulfuric acid is less than solution rosin. Although it is possible to reduce the ratio, the reduction and fluctuation of the size effect in the neutral pH region is unavoidable, which is unsatisfactory.For these reasons, the addition ratio of sulfuric acid bread soil is low and the pH is close to neutral. p
) There is a strong demand for a rosin-based sizing agent that exhibits excellent sizing effects even in the L region.

Cationic rosin emulsion sizing agents are attracting attention as sizing agents that can meet this demand. The cationic rosin emulsion sizing agent has self-fixing properties on pulp fibers, can reduce the amount of sulfuric acid used to achieve the sizing effect, and exhibits excellent sizing effects even in the near-neutral pH range. is shown (TAPPIP Papersakers Conference
nce 1988 pp, 181-188).

However, cationic rosin emulsions are difficult to manufacture industrially compared to anionic emulsions, which were traditionally made by boat, and there are still problems with the product's static stability and performance. More defeat is required.

Although there are several prior art technologies related to cationic rosin emulsion sizing agents, they can be broadly classified into two manufacturing methods. One method is to emulsify a water-insoluble rosin substance using a cationic emulsifying dispersant, and the other method is to mix a cationic component into an anionic rosin emulsion and convert it into a cationic emulsion. It's a method.

Regarding the former, Japanese Patent Publication No. 58-34509 (Japanese Unexamined Patent Publication No. 50-36703, U.S. Patent No. 39666)
54), which describes a method of dispersing reinforced rosin with a water-soluble cationic resin dispersant such as a polyaminopolyamide-epichlorohydrin resin, an alkylene polyamine-epichlorohydrin resin, or a poly(diallylamine)-epichlorohydrin resin; In this method, water-insoluble reinforced rosin is directly emulsified and dispersed with a cationic resin dispersant using a homogenizer or the like. However, since the emulsifying and dispersing function of these cationic resins for rosin-based substances is not sufficient,
As mentioned in Publication No. 27649, there is a problem with storage stability. Furthermore, the content of the cationic resin in the emulsion has to be increased, resulting in problems such as high product costs and excessive foaming in the papermaking system using the emulsion.

On the other hand, as a prior art of the latter, British Patent No. 2141
751A and British Patent No. 2159183A, which include commonly used anionic rosin emulsions and positively charged organic polymer electrolytes (preferably polydi(lower alkyl) diallyl quaternary ammonium chloride) or inorganic cationic rosin emulsions. Polymer (preferably aluminum polyhydroxychloride) is mixed using a high speed mixer to form a “One 5ho”
In these methods, ``When a rosin emulsion and a cationic substance are mixed, agglomeration initially occurs;
More stirring 14! If you do this, you will get a stable product for 2-3 weeks, and even if separation occurs, it will be redispersed by stirring."This is an extremely unstable dispersion that essentially consists of non-uniform aggregated particles. It is the body.

[Problems to be Solved by the Invention] As described above, conventional cationic rosin emulsion sizing agents have problems with storage stability, and improvement thereof has been desired.

Therefore, the present invention provides a cationic rosin emulsion sizing agent that has excellent storage stability, exhibits excellent sizing effects even at near-neutral papermaking pH, and can be easily produced on an industrial scale, and a method for producing the same. This is what we provide.

[Means to solve the problem]

As a result of intensive research on the method for producing cationic rosin emulsions, the present inventors have discovered that conventionally commercially available anionic rosin emulsions are mixed with vinyl copolymerized cationic polymers and/or The present inventors discovered that by mixing with cationized starch, anionic particles can be converted to cationic particles without causing any agglomeration of emulsion particles, and a cationic rosin emulsion with excellent storage stability can be obtained, and the present invention has been completed. reached.

That is, the present invention provides (a) a rosin emulsion having anionic properties, (b) an acrylamide-based polymer and/or a methacrylamide-based polymer, and (c) a vinyl-based copolymerizable cationic polymer and/or a cationized starch, the rosin emulsion having an anionic property. When used alone, modified starch contains cationized starch in which 0.25 mol or more of a cationizing agent is reacted per 1 mol of anhydroglucose of starch, and the above (a) component and (c) component are combined with (b). The present invention provides a cationic rosin emulsion sizing agent characterized by being stabilized by certain components.

At this time, the above (b) component is (b-1) cationic monomer 10 mol% or less (b
-2) Anionic monomer 5 mol% or less (b-3
) Hydrophobic monomer 15 mol % or less (b-4) Acrylamide and/or methacrylamide 70 mol % or more of a monomer in the presence of 10 mol % or less of alkyl mercaptan having 6 to 22 carbon atoms based on the total monomers, (
b-3) It is preferable that the polymer is polymerized by containing at least 0.01 mol % of either or both of a hydrophobic monomer and an alkyl mercaptan.

Next, the present invention will be explained in detail.

When a cationic substance is directly mixed into an anionic rosin emulsion, it generally causes severe agglomeration of the emulsion particles and cannot exist as a stable emulsion (dispersion). Although it is possible to temporarily disperse emulsion particles by strong stirring, it cannot be said to be a stable emulsion, and it is difficult to obtain one with good storage stability and a constant size effect.

On the other hand, several methods have been discovered for converting anionic emulsions, latexes, and dispersions into cationic ones. For example, a method in which an anionic latex is added to an excess amount of a polyelectrolyte solution (polyvinylbenzyltrimethylammonium salt) under vigorous l'tI''! A method of adding a cationic emulsifier afterward (Jikai lli! l6o-152537 publication), and after adding an amine stabilizer and anionic dispersant having cationic properties at P) 16.5 or less to an anionic emulsion. , a method of lowering the pH of the emulsion to 6.5 or less (Japanese Patent Application Laid-Open No. 64-34434), etc. However, as in the present application, 1; (meth)acrylamide-based polymer and vinyl-based copolymerized cationic polymer. and/or in combination with cationized starch has not been found in the past.

In addition, among the prior art related to rosin emulsion sizing agents, there are those related to cationic rosin emulsion sizing agents using the above-mentioned water-soluble cationic resin (polyaminopolyamide-ebichlorohydrin resin, etc.) as a dispersant (
JP-A-50-36703) and rosin emulsion sizing agents containing modified polyacrylamide resin (JP-A-56-169898) exist, but as in the present invention, anionic rosin emulsions and (meth) sizing agents exist. No description has been found regarding a stable cationic rosin emulsion sizing agent comprising an acrylamide polymer, a vinyl copolymerizable cationic polymer, and/or a cationized starch.

The anionic rosin emulsion sizing agent (a) in the present invention is one in which a rosin-based substance is emulsified and dispersed using an anionic surfactant or an anionic polymer dispersant. Available for use. The properties of this anionic rosin emulsion, such as its size performance and mechanical stability, as well as its particle state, especially its particle size distribution, affect the performance of the final product, the cationic emulsion. It is desirable to use a material with a narrow particle size distribution and good performance.

Amount of water! II (b) Acrylamide polymer and/or
Alternatively, the methacrylamide-based polymer has as monomer components (b-1) a cationic monomer of O to 10 mol%, preferably O to 7 mol%, and (b-2) an anionic monomer of O to 5 mol%, preferably O to 3 mole%
, (b-3) O to 15 mol% of the hydrophobic monomer, preferably O to 10 mol%, and (b-4) 70 to 100 mol% of either acrylamide and methacrylamide or a mixture of both. 80-10
It is obtained by polymerizing or copolymerizing the above monomers in the presence of an alkyl mercaptan having 6 to 22 carbon atoms in an amount of 0 to 10 mol%, preferably 0.01 to 5 mol% of the total monomers. be. However, (b-3)
The total amount of either or both of the hydrophobic monomer and the alkyl mercaptan must be 0.01 mol % or more.

If the monomer component composition ratio of the polymer (b) is outside the above range, it tends to cause aggregation or thickening of the particles of the obtained cationic rosin emulsion. In addition, the polymer is a weak anion ~
It is preferable to have a nonionic to weak cationic charge,
This can be achieved by combining either or both of (b-1) cationic monomer and (b-2) anionic monomer within the above monomer composition ratio range.

(b-1) Examples of the cationic monomer include (mono- or di-alkyl)amino(hydroxylalkyl(meth)acrylate, (mono- or di-alkyl)aminoalkyl(meth)acrylate, vinyl Examples include pyridine, vinyl imidabules, diallylamine, and quaternary ammonium salts thereof, which may be used singly or in combination of two or more.

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

The above (b-3) hydrophobic monomer and alkyl mercaptan are for imparting hydrophobicity to the above (b) polymer, and at least one of them or the total of both is required to be 0.01 mol% or more. This is the ingredient that is used. It does not contain both, or the total of both is 0.
When a polymer containing less than 0.01 mol % was used, the stability of the resulting cationic emulsion was poor, and a tendency toward particle aggregation and thickening was observed. The reason why these hydrophobicity-imparting moieties contribute to stability is not clear, but the presence of an appropriate amount of hydrophobic groups in the polymer molecule or at the end increases adsorption to emulsion particles, making the particles more stable. It is imagined that

Examples of the hydrophobic monomer (b-3) include styrene or its derivatives, alkyl (meth)acrylates, vinyl esters such as vinyl acetate or vinyl propionate, or methyl vinyl ether,
If one of these monomers is present, the stability of the resulting emulsion may be poor, or in order to stabilize it (meta)
This is not preferable because the amount of the acrylamide polymer becomes too large, resulting in a decrease in size performance.

Further, as the alkyl mercaptan having 6 to 22 carbon atoms, the alkyl group may be linear or branched,
The raw material for the alkyl group may be either natural or artificially produced, such as by cracking low polymerized paraffin with ethylene or propylene. Examples include normal-octyl mercaptan, tertiary-dodecyl mercaptan, normal-dodecyl mercaptan, normal-octadecyl mercaptan, and normal-hexadecyl mercaptan. used.

Among these, normal-octyl mercaptan and normal-dodecyl mercaptan are preferred. Not only is the amount of alkyl mercaptan not introduced into the polymer during the polymerization reaction large, it may adversely affect the stability and size effect of the reemulsion, and it is also economically unfavorable. It goes without saying that the alkyl mercaptan is used not only to introduce hydrophobic groups into the polymer as described above, but also to control the molecular weight of the polymer as a chain transfer agent.

As a method for synthesizing the (meth)acrylamide-based polymer (b), conventionally known methods can be applied.

For example, the above monomers (b-1) to (b-4) are mixed in a lower alcohol such as methyl alcohol, ethyl alcohol or isopropyl alcohol, or with these lower alcohols or water in the presence of an alkyl mercaptan having 6 to 22 carbon atoms. It is obtained by polymerizing in a mixed solution using a radical polymerization catalyst and distilling off the lower alcohol after the polymerization is completed. Examples of radical polymerization catalysts include persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate, redox polymerization catalysts using a combination of these persulfates and a reducing agent, or 2,2゛-azobisisobutyronitrile. Examples include azo catalysts. Further, if necessary, a known chain transfer agent may be appropriately used in combination.

The viscosity of the polymer solution (b) obtained in this way is 10 to 5000 centipoise (20% by weight aqueous solution).
However, those having a viscosity measured at 25° C. at 60 revolutions per minute using a Brookfield viscometer are preferred, and those having a viscosity of 100 to 1000 centivoise are particularly preferred. When this viscosity is outside the above range, the miscibility with the anionic emulsion and the stability of the cationic emulsion sizing agent prepared using the same tend to be poor.

The polymer (b) is required to have a solid content of 2% or more based on the solid content of the anionic emulsion (a), but from the standpoint of size performance and economic efficiency of the resulting emulsion sizing agent, A range of 5 to 10% by weight is preferred.

The vinyl copolymerizable cationic polymer as component (c) of the present invention is, 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 preferably 12 mol% or more of imidazole, diallylamine, etc. or a mixture of two or more of these quaternary ammonium salts as a cationic monomer, and a 20% by weight aqueous solution thereof. The viscosity is 5
~2000 centipoise is preferred.

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, etc., or raw starch oxidized with mineral acid, sodium hypochlorite, hydrogen peroxide, etc. Processed starch that has been cationized with a cationizing agent can be used.

As a means of cationization, for example, 3-chloro-2-
Examples include a method of reacting starch with a cationizing agent such as hydroxypropyltrimethylammonium chloride, glycidyltrimethylammonium chloride, and diethylaminoethyl chloride. The degree of cationization is such that the number of cationic groups per mole of anhydroglucose in starch is 0.01 mole or more, more preferably 0.03 mole or more, from the viewpoint of storage stability and size performance of the resulting cationic rosin emulsion. When using cationized starch alone, it is desirable that the cationic group is 0.25 mole or more. In order to increase the stability of the obtained cationic rosin emulsion, in addition to the cationization reaction of starch, for example, the introduction of nonionic groups through etherification and esterification reactions, or heat treatment in the presence of an acid to reduce the viscosity. Cationized starch can also be used.

The amount of the vinyl copolymerizable cationic polymer and/or cationized starch used as component (c) above depends on the anionicity of the anionic rosin emulsion and the ionicity of the (meth)acrylamide-based polymer (b). The amount may be at least as long as it can essentially convert the emulsion into a cationic emulsion, but from the economic point of view, 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 is to add (a) the anionic rosin emulsion to the (meth)acrylamide-based polymer (b) under gentle stirring, and then (c) add the vinyl A method of adding a copolymerizable cationic polymer and/or cationized starch is preferred.

The thus obtained cationic rosin emulsion sizing agent of the present invention is not only easier to manufacture than conventional methods, but also has an anionic rosin emulsion with a (meth)acrylamide polymer interposed therein.
It hardly causes particle aggregation and is efficiently cationized with a vinyl copolymerizable cationic polymer and/or cationized starch, so it has excellent storage stability and mechanical stability. In addition, it not only exhibits excellent sizing effects not seen in conventional sizing agents, not only in acidic papermaking systems, but especially in neutral papermaking systems, and also has the advantage of less foaming in papermaking systems. There is.

[Example〕 Next, the present invention will be specifically explained using examples.

In addition, "1 part" indicates weight %.

■Production of anionic rosin emulsion■-1
Production of fumaric acid-enhanced rosin 7 parts of fumaric acid is gradually added to 46 parts of gum rosin in a molten state at 200°C, and after almost all of the fumaric acid has reacted, it is further treated with formaldehyde (modification rate). 3%> 47 parts of tall oil rosin was added, melted and stirred to homogenize, and then the reaction product was cooled to room temperature.This reaction product (fortified rosin) was a rosin with 7% fumaric acid added. Ta.

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

As a representative example of the rosin emulsion using the emulsion anionic polymer dispersant of (A-1), the saponified styrene-methacrylic acid copolymer of Reference Example 8 of JP-A-61-108795 was used. An anionic rosin emulsion (A-1) was obtained according to Example 3.

That is, 250 parts of the fumaric acid reinforced rosin obtained in ①-1 was heated and melted at about 150°C, and while stirring vigorously, the styrene-methacrylic acid copolymer saponification 8 of Reference Example 8 of the above publication was carried out.
135 parts and 20% polyoxyethylene (polymerization! LL2)
7 parts of dodecyl phenyl ether sulfate ammonium salt was added and mixed to form a water-in-oil emulsion. Hot water was gradually added to this to invert the phase to form an oil-in-water emulsion, and hot water was quickly added to this to form a stable oil-in-water emulsion, which was then cooled to room temperature. The total amount of hot water used for phase inversion and dilution was 211 parts, and the emulsion (A-1) thus obtained contained approximately 45% of solids. It was an activator, and about 7.5% was a saponified product of styrene-methacrylic acid copolymer, which was stable over a long period of time.

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

■Approximately 150 parts of fumaric acid-fortified rosin obtained in -1
After heating and melting C, add a small amount of water, lower the temperature to about 130°C, add and mix 50 parts of ammonium salt of 20% polyoxyethylene (degree of polymerization 12) octylphenyl ether sulfate, and mix in oil. It was made into a water emulsion. Hot water was gradually added to this to invert the phase to form an oil-in-water emulsion, and hot water was quickly added to this to form a stable oil-in-water emulsion, which was then cooled to room temperature. The total amount 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.

Emulsion (A-3) A representative example of an anionic rosin emulsion using casein as a dispersant was obtained by the following method with reference to JP-A-63-2813297.

■ Approximately 150 parts of fumaric acid-fortified rosin obtained in -1
After heating and melting at °C and adding a small amount of water, approximately 130"C
The temperature dropped to 171 for casein! L Caustic potash 3.5
1 part of a 5% aqueous casein solution containing 4 parts of sodium tetraborate was added to form a water-in-oil emulsion.

Hot water was gradually added to this to invert the phase to form an oil-in-water emulsion, and hot water was quickly added to this to form a stable oil-in-water emulsion, which was then cooled to room temperature.

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

(2) Production of (meth)acrylamide-based polymers (Meth)acrylamide-based polymers (B-1) to (B-9) were produced as follows.

Polymer aqueous solution of (B-1) Into a 1 g four-bottle flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, add 9.41 L of dimethylaminoethyl methacrylate, 1311 iL of a 50% aqueous solution of acrylamide, and 1.4 liters of acrylic acid. Ion exchange water 107.61! Isopropyl alcohol
0.8 part of 134.61aL normal-dodecyl mercaptan was adjusted to pH 4 with a 20% aqueous sulfuric acid solution. This mixed solution 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 and maintained for 1.5 hours. , 0.7 part of a 5 part percent aqueous solution of ammonium persulfate was added. Furthermore, after maintaining the same temperature for 1 hour, 200 parts of ion-exchanged water was added and the isopropyl alcohol was distilled off.

After the completion of distillation, ion-exchanged water was added and the resulting polymer solution (T1) had a solid content concentration of 20.3%, 25°C1/min 6
The Brookfield viscosity (hereinafter referred to as viscosity) measured at 0 rotations was 410 centivoices (cps). The solid content, viscosity, etc. are shown in Table 1.

Polymer aqueous solutions of (B-2) to (B-9) The method for producing the polymer described in (B-1) above except that the monomer compositions shown in Table 1 were used and the ratio of isopropyl alcohol to water was changed as appropriate to adjust the viscosity. Similarly, (B-2) to (B
-9) An aqueous polymer solution was obtained. The solid content, viscosity, etc. are shown in Table 1.

(Leaving space below) Table 1 Composition and physical properties of (meth)acrylamide-based polymers In the table above EMA EMAC PMA PA AA AA t -I -2 -3 -4 -5 Dimethylaminoethyl methacrylate Methyl chloride quaternized product of DEMA Dimethylamino Probyl methacrylamide dimethylaminobrobyl acrylamide acrinone methacrylic acid itaconic acid styrene normal - dodecyl mercaptan tertiary - dodecyl mercaptan normal - octadecyl mercaptan normal - octyl mercaptan normal - butyl mercaptan ■ Vinyl copolymerization type cationic polymer and cationization Example of producing starch: Vinyl copolymer cationic PO'J
T-(c-1) to (c-3), cationized starch (c-
4, C-5) was produced.

(c-t) of the vinyl copolymerized cationic polymer was placed in an IQ four-bottle flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube. 114 parts of 50% aqueous solution of acrylamide, 150 parts of ion exchange water
1 part of isopropyl alcohol and 1 part of n-dodecyl mercaptan were added, and the pH was adjusted to 4 with a 20% aqueous sulfuric acid solution. While stirring this mixture, the temperature was raised to 60°C under a nitrogen gas atmosphere. 2.3 parts of a 5% solution of ammonium persulfate was added as a polymerization initiator and the mixture was heated to 78°C.
After raising the temperature to 1.5 hours and holding it for 1.5 hours, 0.7 part of a 5% aqueous solution of ammonium persulfate was added.

Furthermore, after holding at the same temperature for 1 hour, ion exchange water 2
00 parts were added and the isopropyl alcohol was distilled off. After completion of distillation, ion-exchanged water was added to obtain the poly7-
The solids concentration of the solution was 20% and the viscosity was 235 centipoise.

(c-2) Vinyl copolymerizable cationic polymer (c
61.5L of methyl chloride quaternized dimethylaminopropylacrylamide using the same reactor as in -1)
7ri1JJL, 7miF'17) 50% aqueous solution 85.
3 parts, ion-exchanged water 208.81 L Isopropyl alcohol 195.61 Normal-dodecyl mercaptan 1 part water Adjust pH with 20% sulfuric acid aqueous solution
Section ii has been added to Section 4. This mixed solution was heated to 60°C under a nitrogen gas atmosphere while stirring. 2.3 parts of a 5% solution of ammonium persulfate was added as a polymerization initiator, and the temperature was raised to 78°C, held for 1.5 hours, and then Added 0.7 parts of a 5% solution of ammonium sulfate.

Furthermore, after keeping it at the same temperature for 1 hour, add ion-exchanged water.
200 parts was added and the isopropyl alcohol was distilled off. After the distillation was completed, ion-exchanged water was added, and the resulting polymer solution had a solid content concentration of 20% and a viscosity of 260 centiboise.

Vinyl copolymerizable cationic polymer of (c-3) (for comparative example) Using the same reactor as (c-1), 8.5 parts of methyl chloride quaternized product of dimethylaminopropylacrylamide, 50% aqueous solution of acrylamide 135.1 parts, ion exchange water 105.8 parts, isopropyl alcohol 1
34.8i, 1 part of normal-dodecyl mercaptan was charged, and the pH was adjusted to 4 with a 20% aqueous sulfuric acid solution. The temperature of this mixed solution was raised to 60"C under a nitrogen gas atmosphere while stirring. 2.3 parts of a 5% solution of ammonium persulfate was added as a polymerization initiator, and the temperature was raised to 78°C and held for 1.5 hours. Added 0.7 parts of a 5% solution of ammonium persulfate.Furthermore, after keeping the mixture at the same temperature for 1 hour, 200 parts of ion-exchanged water was added to distill off the isopropyl alcohol.After the completion of distillation, ion-exchanged The polymer solution obtained by adding water had a solid content concentration of 20% and a viscosity of 320 centipoise.

Production side of cationized starch (c-4) 100 parts of hydrogen peroxide-treated cornstarch was added to 285 parts of water, and the mixture was stirred at 85°C for 1 hour. Next, increase the temperature to 60
The temperature was lowered to below .degree. C., and 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 below 30''C, and 1.8 parts of water 1811 and 98% sulfuric acid were added.

The returned processed starch solution had a solids concentration of 20% and a viscosity of 360 centiboise at 25°C.

(c-5) The cationized starch solution obtained in production example (c-4) of cationized starch was purified with sulfuric acid.
The temperature was adjusted to H3 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.

■Manufacture of cationic rosin emulsion sizing agent■-
1 Examples Examples 1 to 8 A predetermined (meth)acrylamide-based polymer and water were charged in a flask equipped with a stirrer at the compounding ratio (solid content weight ratio) as shown in Table 2.Water and rosin emulsion were added under ft. Then, a vinyl copolymer type cationic polymer and cationized starch were added, and the mixture was allowed to stand for about 10 minutes to obtain a cationic rosin emulsion sizing agent.

As is clear from the zeta potential values shown in Table 2, all of the obtained sizing agents were cationic, and the average particle diameter showed almost no aggregation, indicating that they were stable cationic rosin emulsion sizing agents.

In addition, the measurement of zeta potential was performed using a sizing agent sample at 10-
After diluting to 0.01% with 3M potassium chloride solution and adjusting the pH to 7 with caustic potassium, zetameter (Lazer-
Measured by Zee Meter (manufactured by Penkem),
■Displayed as V.

In addition, the average particle diameter is 0.2% when the sizing agent sample is mixed with water.
Diluted to? & Master 5izer (manufactured by Malvern), and the value was expressed in μm.

(2) Comparative Example Comparative Examples 1 to 8 Sizing agents were prepared in the same manner as in Examples 1 to 8 using the compounding ratios shown in Table 2. However, in Comparative Examples 6 to 8, no (meth)acrylamide-based polymer was used. All samples other than Comparative Example 5 either coagulated or did not coagulate but contained a large amount of aggregates, resulting in large average particle diameters and poor storage stability.

An emulsion was obtained as follows.

Dissolve 300 parts of the fumaric acid-enriched rosin of (1) above in 300 parts of benzene, add 400 parts of the aminopolyamide epichlorohydrin resin solution (solid content 50 parts) prepared in Reference Example 17 of the above US patent specification, and 350 parts of water. The mixture was passed through an industrial homogenizer twice at a pressure of about 150 Kg/cm2 and then all benzene was removed by vacuum distillation.The resulting rosin emulsion had a solids content of about 35%. , about 85 of them
% was reinforced rosin and about 15% was aminopolyamide epichlorohydrin resin.

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

The above example, ratio Table 2 shows the composition and properties of the sizing agent of Comparative Example.

(Margins below) Table 2: Cationic rosin emulsion sizing agent Using each sizing agent prepared in the above Examples and Comparative Examples, sizing effects, static stability, and foaming properties were tested.The test conditions are as follows. Shown below.

■ Size effect test bleached kraft bulb (softwood to hardwood bulb ratio 1:4)
Mixed pulp) was mixed with diluting water with a hardness of 100 ppm in an amount to give a pulp concentration of 2.5% using a beater.
Beaten to 50+*1 Canadian Standard Freeness.

Next, 1.2Q of the pulp slurry was weighed into a disintegrator, and a sizing agent of 0.5% (solid content weight ratio) to the valve and sulfuric acid bread soil of 0.25% (solid content weight ratio) to the valve were added simultaneously. The pH was adjusted to a value of 7 with NaOH and the pH was adjusted to a value of 30.
Stir for a minute. Next, this pulp slurry was diluted to a concentration of 0.25% with dilution water of pH 7, and cationic polyacrylamide polymer was used as a fixing agent to give a concentration of 0.05% for valves (
Solid content weight ratio> was added and paper was made using a Nople and Wood paper machine.

The wet paper obtained here was pressed to a solid content of 40%, and then dried at 100° C. for 60 seconds using a drum dryer. The paper pieces thus obtained were kept at a constant temperature (20°C-60°C).
% relative humidity) environment for 24 hours to prepare a test paper material (Basic weight e 5 g/lL The degree of sizing was measured by the Stekicht method. The results are shown in Table 3.

■ Foaming test using the same pulp slurry as in the above papermaking test;
．． 25% (solid content weight ratio) of sulfuric acid bread earth was added at the same time, and the pH was adjusted to 7 with caustic soda. After stirring for 3 minutes, the pulp slurry was diluted to 0.25% with pH 7 dilution water.
Dilute to 0.0 and use a cationic acrylamide polymer as a fixing agent. After adding S% (solid content weight ratio) and stirring for 1 minute, the pulp slurry was placed in a cylindrical container and a part of this pulp slurry was circulated with a pump and dropped into the container from a height of about 1. The area of the bubbles accumulated on the liquid surface after 10 minutes was determined, and the accumulated bubble area relative to the entire liquid surface was expressed as a percentage.

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

(Left below) Table 3: Cationic rosin emulsion sizing agent, stability and foaming properties Note that when a vinyl copolymerizable cationic polymer and cationized starch are used together as component (c), at least when the above is used alone. The same effect can be obtained.

[Effects of the Invention] According to the present invention, an anionic rosin emulsion, a vinyl copolymerized cationic polymer and/or a cationized starch are stabilized with an acrylamide polymer and/or a methacrylamide polymer, and the cationic Not only is it easier to manufacture than conventional cationic rosin emulsion manufacturing methods, but anionic rosin emulsions almost eliminate particle aggregation by intervening acrylamide-based and/or methacrylamide-based polymers. Because it is efficiently cationized with a vinyl copolymerizable cationic polymer and/or cationized starch without causing any oxidation, it has excellent storage stability and mechanical stability. In addition, it not only exhibits excellent sizing effects not seen in conventional sizing agents, not only in acidic papermaking systems, but especially in neutral papermaking systems, and also has the advantage of less foaming in papermaking systems. November 30, 1999

Claims (6)

[Claims] (1) (a) Anionic rosin emulsion (
b) an acrylamide-based polymer and/or a methacrylamide-based polymer; (c) a vinyl-based copolymerizable cationic polymer and/or a cationized starch; when the cationized starch is used alone, the amount per mole of anhydroglucose in the starch; A cationic rosin emulsion sizing agent containing cationized starch reacted with 0.25 mol or more of a cationizing agent, and characterized in that the above components (a) and (c) are stabilized by component (b). . (2) Component (b) according to claim 1 contains 10 mol% or less of the (b-1) cationic monomer (b-2
) 5 mol % or less of anionic monomer (b-3) 15 mol % or less of hydrophobic monomer (b-4) Monomer consisting of 70 mol % or more of acrylamide and/or methacrylamide, 10 mol % or less of the total monomers It is characterized by being polymerized in the presence of an alkyl mercaptan having 6 to 22 carbon atoms, containing 0.01 mol% or more of either or both of the hydrophobic monomer (b-3) and the alkyl mercaptan. The cationic rosin emulsion sizing agent according to claim 1. (3) The cationic rosin emulsion according to claim 2, characterized in that the monomer content of each of (b-1), (b-2), and (b-3), or any two or all of the components is zero. Sizing agent. (4) The cationic rosin emulsion sizing agent according to claim 2 or 3, characterized in that the alkyl mercaptan is 0. (5) Consisting of components (a), (b), and (c) according to claim 1, the anionic rosin emulsion of (a) is stabilized by mixing and dispersing (a) and (c) in the presence of (b). A method for producing a cationic rosin emulsion sizing agent for converting it into a cationic rosin emulsion. (6) A method for producing a cationic rosin emulsion sizing agent according to claim 5, characterized in that the component (b) according to any one of claims 2 to 4 is used.