CN1208517C - Surface-sizing agent - Google Patents

Abstract

A surface-sizing agent for papermaking which itself is excellent in mechanical stability and storage stability, and which is highly suitable for the sizing of acidic to neutral papers. When applied to papers for information, especially ink-jet printing papers, the sizing agent imparts excellent suitability for ink-jet printing. When the sizing agent is used to prepare a coating fluid, the coating fluid is significantly reduced in foaming. The sizing agent has excellent compatibility with other chemicals to be used in combination therewith. The surface-sizing agent is characterized by being obtained by polymerizing a nonionic hydrophilic monomer (b) with a hydrophobic monomer (d) in the presence of an alkali salt of shellac (a) and then mixing a polymeric dispersant (e) therewith.

Description

surface sizing agent

technical field

The present invention relates to surface sizing agents, and more specifically, to mechanical stability, storage stability, sizing performance for acidic paper to neutral paper, suitability for information paper, low Surface sizing agent for papermaking with excellent foamability and compatibility with other concomitant drugs.

Background technique

As far as the current surface sizing agents for papermaking are concerned, there are known styrene-maleic acid copolymers, styrene-(meth)acrylic acid copolymers, α-olefin-maleic acid copolymers, Aqueous solutions of alkali metal salts such as substances.

Although the surface sizing agent of styrene-maleic acid copolymer shows a good sizing effect for acidic papermaking that uses a lot of alum, it has a small amount of alum for neutral papermaking that does not use alum. The sizing performance of the neutral papermaking paper is significantly poor.

In addition, since the sizing agent itself foams a lot during surface coating, it is necessary to increase the amount of antifoaming agent used. As a result, repelling occurs on the coated surface, which deteriorates the sizing effect.

Although the surface sizing agent of styrene-(meth)acrylic acid copolymer shows a relatively good STICKY HIT sizing degree for the above-mentioned neutral papermaking paper, it is difficult to record due to poor pen leakage. There are problems such as text leakage. In addition, the coating liquid prepared using this surface sizing agent has significantly poor stability against metal ions, so there are operational problems such as the generation of aggregates (called 'meal' at the factory) and excessive foaming.

Although the surface sizing agent of α-olefin-maleic acid-based copolymer shows good pen bleeding, if it is used for PPC paper, the fastness of the toner is low, and if it is used for printing paper In this case, there is a problem in ink contact, and the coating liquid prepared using this surface sizing agent has problems in operation such as a lot of foaming.

And, the patent of the latex type surface sizing agent manufactured by emulsion polymerization method, existing several are reported as prior art type.

For example, in Japanese Patent Application Laid-Open No. 8-246391, it is disclosed that "in 100 parts by weight of water-soluble copolymer containing [B], that is, (1) carboxyl group-containing unsaturated monomer and (2) hydrophobic unsaturated monomer, A surface sizing agent for papermaking composed of latex obtained by emulsion polymerization of 10 to 500 parts by weight of [A] a hydrophobic unsaturated monomer in an aqueous solution.

Compared with the current solution-type surface sizing agent, the particle-type surface sizing agent has compatibility with other concomitant drugs, and stability with respect to dissolved metal ions when preparing the coating liquid, or the coating liquid The foamability has been improved, but its sizing performance is still insufficient.

And, in the Japanese Patent Laid-Open No. 49-50209, it is disclosed that 'in the alkaline aqueous solution of shellac, at least one monomer selected from styrene and styrene derivatives, or with it as needed A surface finishing agent for paper composed of an aqueous dispersion obtained by mixing other monomers that can be copolymerized and adding a free radical polymerization catalyst for copolymerization.

However, the above-mentioned surface finishing agent emulsifies styrene and styrene derivatives in an ammonia solution of shellac, and though it can improve the water resistance and gloss of paper, it often produces aggregates and the like during emulsification polymerization. There are problems in manufacturing, and the water resistance is not sufficient. In addition, since the obtained surface finishing agent has extremely poor stability against metal ions and mechanical stability, various problems arise in actual operation.

Moreover, recently, not only inkjet paper but also PPC paper have been required to have printing density, feathering, backside bleed, border Inkjet suitability such as bleeding, and it is expected to obtain a sizing agent that satisfies this suitability.

Contents of the invention

The object of the present invention is to provide a surface sizing agent for papermaking. The sizing agent itself has excellent mechanical stability and storage stability, and has excellent sizing performance for acidic paper to neutral paper, and is suitable for information paper, especially It has excellent inkjet applicability to inkjet paper, and when the coating liquid is prepared, the foaming property of the coating liquid is significantly reduced, and the compatibility with other concomitant drugs is excellent.

In order to solve the above-mentioned problems, the present inventors conducted intensive studies repeatedly. As a result, in the presence of at least an alkali metal salt of shellac, at least A hydrophobic monomer and at least one nonionic hydrophilic monomer selected from the group consisting of (meth)acrylamide, acrylonitrile and hydroxyalkyl (meth)acrylate, or the hydrophobic monomer body, the nonionic hydrophilic monomer, and at least one anionic monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, and fumaric acid. After polymerization, at least one polymer dispersant selected from the group consisting of partially or fully neutralized anionic styrene-(meth)acrylic copolymers and polyvinyl alcohol is mixed, or, in addition to shellac In the presence of a reactive emulsifier with a methacryloyl group other than alkali metal salts, the hydrophobic monomer and the nonionic hydrophilic monomer, or the hydrophobic monomer and the nonionic hydrophilic monomer After polymerizing the monomer composed of the above-mentioned anionic monomer, mixing the alkali metal salt of shellac and the polymer dispersant, the surface sizing agent for papermaking that can overcome the above-mentioned problems is produced.

That is, the first aspect of the present invention is:

At least one nonionic hydrophilic monomer selected from the group consisting of (meth)acrylamide, acrylonitrile and hydroxyalkyl (meth)acrylate in the presence of an alkali metal salt of shellac (a) (b) and in the reaction solution obtained by polymerization of at least one hydrophobic monomer (d) selected from the group consisting of styrene derivatives and (meth)alkyl acrylates, mixed with an anionic styrene-( A surface sizing agent obtained from a partial or complete neutralization of a meth)acrylic copolymer and at least one polymer dispersant (e) of the group consisting of polyvinyl alcohol,

The second aspect of the present invention is:

At least one nonionic hydrophilic monomer selected from the group consisting of (meth)acrylamide, acrylonitrile and hydroxyalkyl (meth)acrylate in the presence of an alkali metal salt of shellac (a) (b), at least one anionic monomer (c) selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, and fumaric acid and selected from styrene derivatives, and (methyl ) In the reaction solution obtained by polymerizing at least one hydrophobic monomer (d) of the group consisting of alkyl acrylates, a partially or completely neutralized product selected from anionic styrene-(meth)acrylic copolymers is mixed, And the surface sizing agent obtained by at least one polymer dispersant (e) of the group consisting of polyvinyl alcohol,

The third aspect of the present invention is:

In the presence of a reactive emulsifier (f) having a methacryloyl group in addition to an alkali metal salt of shellac (a), in the group selected from (meth)acrylamide, acrylonitrile and hydroxyalkyl (meth)acrylate At least one nonionic hydrophilic monomer (b) from the group consisting of and at least one hydrophobic monomer (d) selected from the group consisting of styrene derivatives, and alkyl (meth)acrylates In the reaction solution obtained by polymerization, the alkali metal salt (a) of shellac and the partially or completely neutralized product selected from the group consisting of anionic styrene-(meth)acrylic acid copolymer and polyvinyl alcohol are mixed. Surface sizing agent obtained by at least one polymer dispersant (e),

A fourth aspect of the present invention is:

In the presence of a reactive emulsifier (f) having a methacryloyl group in addition to an alkali metal salt of shellac (a), in the group selected from (meth)acrylamide, acrylonitrile and hydroxyalkyl (meth)acrylate At least one nonionic hydrophilic monomer (b) in the group consisting of, at least one anionic monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, and fumaric acid Body (c) and the reaction solution obtained by polymerization of at least one hydrophobic monomer (d) selected from the group consisting of styrene derivatives and alkyl (meth)acrylates, mixed with an alkali metal salt of shellac ( a) and at least one polymer dispersant (e) obtained from a partially or fully neutralized product selected from the group consisting of anionic styrene-(meth)acrylic acid copolymers and polyvinyl alcohol agent,

The surface sizing agent of the fifth aspect of the present invention is characterized by:

Comprising: an alkali metal salt of shellac (a); having at least one nonionic hydrophilic monomer selected from the group consisting of (meth)acrylamide, acrylonitrile and hydroxyalkyl (meth)acrylate (b) and at least one hydrophobic monomer (d) selected from the group consisting of styrene derivatives and (meth)acrylic acid alkyl esters as repeating units, or having the nonionic Hydrophilic monomer (b), at least one anionic monomer (c) selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, and fumaric acid, and the hydrophobic monomer (d) a polymer as a repeating unit; at least one polymer dispersant selected from the group consisting of anionic styrene-(meth)acrylic copolymers and partially or completely neutralized polyvinyl alcohol ( e).

Detailed ways

The surface sizing agent of the present invention is a latex type surface sizing agent. The surface sizing agent is prepared by, in the presence of an alkali metal salt of shellac (a), at least one non- An ionic hydrophilic monomer (b) and at least one hydrophobic monomer (d) selected from the group consisting of styrene derivatives and alkyl (meth)acrylates, or the nonionic hydrophilic In the one-stage polymer in which the monomer (b), the anionic monomer (c) and the hydrophobic monomer (d) are polymerized, an anionic styrene-(meth)acrylic copolymer is mixed with Partial or complete neutralization of the product, and at least one polymer dispersant (e) of the group consisting of polyvinyl alcohol can be obtained, or have a methacryloyl group in addition to the alkali metal salt of shellac (a) In the presence of the reactive emulsifier (f), in the nonionic hydrophilic monomer (b) and the hydrophobic monomer (d), or the nonionic hydrophilic monomer (b) . In the one-stage polymer obtained by polymerizing the above-mentioned anionic monomer (c) and the hydrophobic monomer (d), it can be obtained by mixing the alkali metal salt of shellac (a) and the above-mentioned polymer dispersant (e).

The shellac used in the present invention is to refine the resinous substance secreted by shellac shellworms parasitic on South Sea plants, and is composed of a plurality of resin acid mixtures, for example, shellac (areuric acid), jatrophic acid ( jiyara-lu acid) or chitosinic acid (rakshijara-lu acid) esterified softening resin or a combination of several such softening resin constituted.

The so-called alkali metal salt (a) of shellac in the present invention means that shellac is neutralized with an alkaline substance. The alkaline substance used to obtain the alkali metal salt of shellac is not particularly limited as long as it can substantially hydrate shellac, but caustic soda, caustic soda, and ammonia are preferable. When the usage-amount of the above-mentioned basic substance is more than equivalent to the acid value of shellac, it is preferable in terms of improving the stability during emulsion polymerization and the stability of the obtained surface sizing agent.

In the present invention, if there is an alkali metal salt of shellac during polymerization, the polymerization can be carried out slowly, especially during emulsion polymerization, it has the advantage of being able to obtain fine particles, and the resulting emulsion polymer has good stability and water resistance. Increased, with a tendency to reduce foaming.

As the reactive emulsifier (f) having a methacryloyl group used in the present invention other than the alkali metal salt of shellac, well-known emulsifiers or dispersants can be used. A polymeric-based surfactant, and at least one selected from these groups may be used, and among them, a surfactant having a polymeric-based group is preferable because a surface sizing agent having low foaming properties is obtained.

The above-mentioned low-molecular-weight surfactant can generally use a substance suitable for emulsifying polymers, and can use non-ionic, anionic, amphoteric and cationic low-molecular-weight surfactants, and at least one selected from these groups can be used, Among these, nonionic low-molecular-weight surfactants and anionic low-molecular-weight surfactants are preferred from the viewpoint of latex stability.

Examples of nonionic low-molecular surfactants include polyoxyalkylene alkylphenyl ethers, polyoxyalkylene alkyl ethers, polyoxyalkylene fatty acid esters, polyoxypropylene polyoxyethylene glycol glycerin fatty acid esters , sorbitan fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, sucrose fatty acid ester, pentaerythritol fatty acid ester, propylene glycol fatty acid ester, fatty acid diethanolamide, polyoxygen Propylene polyoxyethylene glycol, etc. In the present invention, the aforementioned nonionic low-molecular-weight surfactants may be used singly or in combination of two or more.

Examples of anionic surfactants include phosphate ester salts of polyoxyalkylene alkylphenyl ethers, polyoxyalkylene mono- and distyrylphenyl ethers, polyoxyalkylene alkyl ethers, and polyoxyalkylene fatty acid esters. , sulfonates, succinates and sulfosuccinates, and alkylbenzenesulfonates, alkali metal salts of naphthalenesulfonic acid formaldehyde condensates, fatty alkenyl succinates, alkali metal salts of rosin and fortified Alkali metal salt of rosin. In the present invention, the aforementioned anionic low-molecular-weight surfactants may be used alone or in combination of two or more.

Examples of the cationic surfactant include tetraalkylammonium chloride, trialkylbenzylammonium chloride, alkylamine, mono- and polyoxyethylene alkylamine, and the like. In the present invention, the aforementioned cationic low-molecular-weight surfactants may be used alone or in combination of two or more.

Surfactants with the above-mentioned polymerizable groups are generally called reactive emulsifiers, compounds with hydrophobic groups, hydrophilic groups and carbon-carbon double bonds in the molecule. The so-called carbon-carbon double bond refers to, for example, double bonds in (meth)allyl, 1-propenyl, 2-methyl-1-propenyl, isopropenyl, vinyl, and (meth)acryloyl, etc. key.

As surfactants having these polymerizable groups, surfactants generally suitable for emulsion polymerization can be used without particular limitation, and specific examples thereof include polyoxyalkylene alkyl ethers having one or more of the above-mentioned functional groups in the molecule. , polyoxyalkylene aralkyl ether, polyoxyalkylene phenyl ether, polyoxyalkylene mono- and distyryl phenyl ether, etc., and their sulfonates, sulfate ester salts, phosphate ester salts, and sulfosuccinate salts. Aliphatic and aromatic carboxylic acid salts of polyoxyalkylene alkyl ethers or polyoxyalkylene phenyl ethers with more than one of the above-mentioned functional groups, acidic phosphoric acid (meth)acrylate compounds, rosin-glycidyl (meth)acrylate series compounds, and alkyl diphenyl ether disulfonic acid compounds, such as hexyl diphenyl ether disulfonic acid, decyl diphenyl ether disulfonic acid, dodecyl diphenyl ether disulfonic acid, hexadecyl diphenyl ether disulfonic acid, hexadecyl diphenyl ether disulfonic acid, Alkali metal salts and ammonium salts of alkyl diphenyl ether disulfonic acid and its sodium salt, potassium salt, etc. In the present invention, the above-mentioned surfactants having a polymerizable group may be used singly or in combination of two or more.

Usually, when the above-mentioned surfactant (f) is used alone without using an alkali metal salt of shellac, it is used in the range of 0.5 to 5 parts by weight with respect to 100 parts by weight of the hydrophobic monomer (d). When an alkali metal salt is used together, it is used in the range of 1-20 weight part with respect to 100 weight part of alkali metals of shellac.

The above-mentioned polymer dispersant (e) used in the present invention can basically use a synthetic polymer or a general natural polymer dispersant with a hydrophobic base, a non-ionic base and/or an ionic base. Examples of molecules include polyvinyl alcohol and its modified products, partially or completely neutralized products of anionic styrene-(meth)acrylic copolymers, and anionic or cationic (meth)acrylate copolymers. Water-based resins such as (meth)acrylamide copolymers, polyesters, polyurethanes, alkyds, and polyamides. Examples of natural polymer emulsifiers include casein, lecithin, cellulose derivatives such as hydroxyethyl cellulose, starch, modified starch, and the like. In the present invention, the above polymer dispersants (e) may be used alone or in combination of two or more. In the present invention, examples of suitable polymer dispersants include salts of styrene-(meth)acrylic acid copolymers, such as ammonium salts, and (meth)acrylate copolymers.

The above-mentioned polymer dispersant (e) can be used in combination with an alkali metal salt of shellac before polymerization, but it is preferably added after polymerization because of the mechanical stability of the latex particles and the dilution with water containing metal ions. Dilution stability is good.

The amount of the polymer dispersant (e) used is in the range of 5 to 100 parts by weight, preferably in the range of 5 to 50 parts by weight, based on 100 parts by weight of the hydrophobic monomer (d). The improvement of the above-mentioned effects was not found, and the reduction of the sizing performance was caused, so it was not good.

In the present invention, if at least one nonionic hydrophilic monomer (b) selected from the group consisting of (meth)acrylamide, acrylonitrile and hydroxyalkyl (meth)acrylate is used as a polymerization component, In particular, it can suppress the generation of aggregates generated by side reactions during emulsion polymerization, and has the advantage of being easy to manufacture, and has good storage stability, stability with respect to metal ions, and good mechanical stability of the obtained surface sizing agent. advantage.

The nonionic hydrophilic monomer (b) used in the present invention is a polymerizable monomer having a hydrophilic group instead of a cationic group and an anionic group, examples of which include (meth)acrylamide, acrylamide, Nitrile, and hydroxyalkyl (meth)acrylate, etc. In the present invention, these nonionic hydrophilic monomers may be used alone or in combination of two or more. The nonionic hydrophilic monomer (b) used in the present invention may be a polymerizable monomer having a hydrophilic group instead of a cationic group and an anionic group, and contains a nonionic water-soluble monomer. Among the above-mentioned nonionic hydrophilic monomers, acrylamide, which is inexpensive and readily available, is preferable.

In the present invention, the water resistance of the obtained surface sizing agent can be improved by using the hydrophobic monomer (d) as a polymerization component.

The hydrophobic monomer (d) used in the present invention includes a water-insoluble monomer. Examples of such hydrophobic monomers include styrene, styrene derivatives such as α-methylstyrene, vinyltoluene, and divinylbenzene, alkyl (meth)acrylates, (methyl) ) cycloalkyl acrylate, dialkyl diesters of maleic acid and fumaric acid, vinyl esters such as vinyl tertiary carboxylic acid with 5 to 10 carbons and vinyl propionate, N Alkyl (meth)acrylamides, methyl vinyl ether, etc. These various hydrophobic monomers may be used alone or in combination of two or more. When using (meth)acrylates and other hydrophobic monomers, the proportion of alkyl (meth)acrylates is at least 25% by weight relative to the total amount of hydrophobic monomers as the compounding ratio, Preferably it is 40 to 100% by weight, and it is good for sizing performance.

In the present invention, if at least one anionic monomer (c) selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, and fumaric acid is used as a polymerization component, emulsification can be further improved. The advantages of stability during polymerization, and can further improve the mechanical stability of the resulting surface sizing agent.

The anionic monomer (c) used in the present invention is a monomer having an anionic group, and examples thereof include (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid. , crotonic acid and other monomers with carboxylic acid groups, vinylsulfonic acid, (meth)propylenesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid, sulfonated styrene and other monomers with sulfonic acid groups Monomers, monomers having phosphate groups such as phosphate esters of hydroxyalkyl (meth)acrylates. These anionic monomers may be used alone or in combination of two or more. Among these, anionic monomers having a carboxyl group are preferable because they impart low foaming properties to the surface sizing agent, and among them, (meth)acrylic acid and itaconic acid are more preferable.

As a combination of the above-mentioned monomer components, at least one nonionic hydrophilic monomer selected from the group consisting of (meth)acrylamide, acrylonitrile, and hydroxyalkyl (meth)acrylate (b) a combination of at least one hydrophobic monomer (d) selected from the group consisting of styrene derivatives and alkyl (meth)acrylates, and the nonionic hydrophilic monomer (b) ) and a combination of the aforementioned anionic monomer (c) and the aforementioned hydrophobic monomer (d). By using the combination of the nonionic hydrophilic monomer (b) and the hydrophobic monomer (d), the purpose of the present invention can be achieved, and if the nonionic hydrophilic monomer is used Combining (b) with an anionic monomer (c) and a hydrophobic monomer (d), an excellent surface sizing agent with improved mechanical stability can be obtained.

That is, the surface sizing agent of the present invention contains at least one nonionic hydrophilic monomer (b) selected from the group consisting of (meth)acrylamide, acrylonitrile, and hydroxyalkyl (meth)acrylate. and at least one hydrophobic monomer (d) selected from the group consisting of styrene derivatives and (meth)acrylic acid alkyl esters as a repeating unit polymer, or the above-mentioned nonionic hydrophilic monomer ( b) A polymer comprising the anionic monomer (c) and the hydrophobic monomer (d) as repeating units.

When the surface sizing agent of the present invention is produced, the alkali metal salt of shellac (a), the reactive emulsifier (f) having a methacryloyl group, selected from (meth)acrylamide, acrylonitrile and (meth) At least one nonionic hydrophilic monomer (b) in the group consisting of hydroxyalkyl acrylate, at least one selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, and fumaric acid An anionic monomer (c), at least one hydrophobic monomer (d) selected from the group consisting of styrene derivatives and alkyl (meth)acrylates and an anionic styrene-(methyl) ) the partially or completely neutralized product of the acrylic copolymer, and the usage amount of at least one polymer dispersant (e) of the group consisting of polyvinyl alcohol, relative to 100 parts by weight of the hydrophobic monomer (d) For example, preferably the alkali metal salt of shellac (a) is 1 to 20 parts by weight, the reactive emulsifier (f) with methacryloyl group is 0.5 to 5 parts by weight, the above-mentioned nonionic hydrophilic monomer ( b) is 1 to 20 parts by weight, the above-mentioned anionic monomer (c) is 0.1 to 10 parts by weight, and the polymer dispersant (e) is 5 to 100 parts by weight. It is good in terms of performance, and more preferably, the alkali metal salt of shellac (a) is 5 to 15 parts by weight, and has a methacryloyl group. The agent (f) is 0.5 to 3 parts by weight, the above-mentioned nonionic hydrophilic monomer (b) is 5 to 15 parts by weight, the above-mentioned anionic monomer (c) is 0.5 to 5 parts by weight, and the polymer dispersant ( e) is 5 to 50 parts by weight. Furthermore, the amount of the above-mentioned reactive emulsifier (f) having a methacryloyl group is the amount used alone when the alkali metal salt of shellac (a) is not used in combination, and when the alkali metal salt of shellac is used in combination In the case of (a), the range of 1-20 weight% is used with respect to the alkali metal salt (a) of shellac.

When producing the surface sizing agent of the present invention, well-known polymerization methods can be used at present, and solution polymerization methods, bulk polymerization methods, emulsion polymerization methods, etc. can be used, but for the ease of manufacture, the emulsion polymerization method is preferred. Moreover, at this time, substantially all of the monomers are polymerized to form a homopolymer or a copolymer, and when shellac exists before the polymerization, it is considered that this shellac also participates in the polymerization.

Examples of the radical polymerization catalyst used in the above polymerization method include persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate; peroxides such as t-butyl hydroperoxide and hydrogen peroxide; , redox-based polymerization catalysts combining these persulfates or peroxides with reducing agents, or 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylpropionamide disalt Azo-based catalysts such as acid salt (2,2'-Azobis-2-Mecholpropionamidine cidololide). Moreover, a well-known chain transfer agent can also be used together as needed.

The pulp used in the base paper to which the surface sizing agent of the present invention is applied includes bleached or unbleached chemical pulp such as kraft pulp or sulfite pulp, ground wood pulp, mechanical pulp, or thermomechanical pulp. Bleached or unbleached high-yield pulp, old newspaper, old magazine paper, corrugated cardboard old paper or deinked old paper, etc.

In order to obtain base paper and express the physical properties required by various papers, fillers, dyes, rosin-based sizing agents for acidic papermaking, alkyl diketene-based or alkenyl succinic anhydride-based neutral papermaking agents can also be used as needed. Additives such as sizing agent, rosin-based sizing agent for neutral papermaking, dry paper strength enhancer, wet paper strength enhancer, productivity improver, drainage improver, defoamer, etc. Examples of fillers include clay, talc, titanium oxide, heavy or light calcium carbonate, and the like. Can be used alone or in combination.

For the coater used for coating the surface sizing agent of the present invention, a size press, a film press, a sprue roll coater, a Sim sizing machine, a knife coater, Calender, Rod Coater, Blade Coater, Air Knife Coater, Curtain Coater, etc. In addition, it can also be coated on the base paper surface by a spray coater.

When coating the surface sizing agent of the present invention, starches such as oxidized starch, phosphated starch, enzyme-modified starch, and cationized starch, celluloses such as carboxymethyl cellulose, polyvinyl alcohol, etc. Water-soluble polymers such as polyacrylamides, sodium alginate, etc. are mixed in the coating liquid and used. In addition, other additives such as surface sizing agents, antislip agents, corrosion inhibitors, rust inhibitors, defoamers, viscosity modifiers, dyes, and pigments may be used in combination.

For the sized paper obtained by coating the surface sizing agent of the present invention on the above-mentioned base paper, various papers and cardboards can be used. Examples include recording paper such as PPC paper, inkjet recording paper, laser printing paper, form paper, thermal transfer paper, thermal recording paper, coated paper, cast-coated paper, and chemical pulp. Coated paper such as coated paper, kraft paper, wrapping paper such as pure white roll paper, printing paper for photographs, other writing paper, book paper, printing paper, western paper such as newsprint, manila board Cardboard for paper containers such as paper, whiteboard, and roughboard, and cardboard for lining boards, etc.

The concentration of the surface sizing agent in the coating solution used for coating the surface sizing agent of the present invention is usually 0.1 to 5% by weight, preferably 0.2 to 1% by weight. If it is less than 0.1% by weight, the sizing effect may be insufficient, and if it exceeds 5% by weight, the sizing effect will hardly be improved, and it is not economical, so it is not good.

In addition, the coating amount is generally 0.01 to 1 g/m ² in terms of solid content, preferably 0.02 to 0.1 g/m ² . If it is the said range, especially favorable sizing effect can be exhibited.

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to these Examples.

(Synthesis Example 1)

According to the reference example 2 of Japanese Unexamined Publication No. 8-246391, the aqueous solution of the ammonium salt (S-1) of the polymer dispersant styrene-acrylic acid copolymer in the present invention, that is, the polymer dispersant solution (S-1) was synthesized as follows. -1 solution).

100 parts of water and 75 parts of 95% isopropanol were added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux cooling pipe, and a nitrogen gas introduction pipe, and heated while stirring until the temperature rose to 80°C. Therein, a monomer mixture liquid of 45 parts of styrene and 55 parts of acrylic acid, and a polymerization initiating solution of 5 parts of potassium persulfate dissolved in 120 parts of water were added dropwise for 3 hours, and then kept for 2 hours to complete the reaction. Thereafter, the isopropanol was evaporated, and after cooling, 46.4 parts of 28% ammonia solution (relative to 100 mol% of acrylic acid) was added and diluted with water to adjust the concentration of the copolymer to 20% to obtain a water-soluble copolymer of styrene - An aqueous solution of an ammonium salt (S-1) of an acrylic acid copolymer, that is, a polymer dispersant solution (S-1 solution).

(Synthesis Example 2)

In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux cooling pipe, and a nitrogen inlet pipe, add 586 parts of water, 80 parts of styrene, 39 parts of α-methylstyrene, 22 parts of methyl methacrylate, and 75 parts of acrylic acid, 3.3 parts of n-dodecyl mercaptan, 1 part of sodium dodecylbenzenesulfonate, and 33 parts of 30% ammonium persulfate aqueous solution, and heated to 80°C, and kept at 80°C for 2 hours so that The reaction is complete. Then, 121 parts of 30% caustic soda solutions (95 mol% with respect to methacrylic acid) were added, and it maintained at 80 degreeC for 30 minutes. Diluted with water, adjusted to make the copolymer concentration 25%, and obtained the aqueous solution of the sodium salt (S-2) of the water-soluble copolymer styrene-methacrylic acid copolymer, that is, the polymer dispersion solution (S-2 solution) .

(Example 1)

In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux cooling pipe, and a nitrogen gas introduction pipe, 535 parts of water and 13.2 parts of shellac (N811 manufactured by Gifu SHELLAC Co., Ltd.) were added (100 parts by weight of the entire hydrophobic monomer) 8 parts by weight), ELEMINOL JS-2 (manufactured by Sanyo Chemical) 4.2 parts (1 part by weight when the total hydrophobic monomer is 100 parts by weight), acrylamide 12.9 parts (1 part by weight when the total hydrophobic When 100 parts by weight, it is 8 parts by weight), 3.4 parts of 48% caustic, and then add 64.5 parts of styrene (when the whole hydrophobic monomer is 100 parts by weight, it is 40 parts by weight), n-butyl acrylate 96.7 parts (60 parts by weight when the total hydrophobic monomer is 100 parts by weight), and 0.8 parts of ammonium persulfate, the temperature was raised to 80° C. while mixing and stirring under a nitrogen stream. Keep at 80 DEG C for 2 hours to complete the emulsification polymerization reaction, add 161 parts of polymer dispersant solution (S-1 solution) (when the whole hydrophobic monomer is 100 parts by weight, S-1 is 20 parts by weight), and obtain a solid A latex type surface sizing agent with a content concentration of 25.3%.

(Example 2-9, Comparative Examples 1-4)

In addition to making the dispersant before polymerization, at least one nonionic hydrophilic monomer selected from the group consisting of (meth)acrylamide, acrylonitrile and hydroxyalkyl (meth)acrylate, selected from acrylic acid, methacrylic acid The type and amount of at least one anionic monomer selected from the group consisting of acrylic acid, maleic acid, and fumaric acid, selected from the group consisting of styrene derivatives, and alkyl (meth)acrylates The type and amount of at least one hydrophobic monomer, and the type and amount of the polymerized dispersant were changed as shown in Table 1, except that the same treatment as in Example 1 was performed to obtain a latex-type surface sizing agent.

(comparative example 5)

Comparative Example 5 used a commercially available styrene-acrylic surface sizing agent SS315 (manufactured by Japan PMC Corporation).

(Test example 1) Evaluation of acidic high-quality paper

(1) Manufacture of base paper for acidic high-quality paper

380 ml of pulp mashed to Canadian Standard Freeness (a 9:1 blend of hardwood to conifer pulp) was made into a 2.5% slurry to which was added 15% relative to the pulp (absolute dry weight basis) talc powder (manufactured by Fuji TALC Industries: ND TALC). In this, after sequentially adding 2% (absolute dry weight basis) of alum relative to the pulp, 0.3% (absolute dry weight basis) of acidic rosin-based sizing agent for paper (manufactured by Japan PMC; AL120) relative to the pulp, the pH4 .5 dilution water to dilute the pulp slurry to a consistency of 0.25%. Thereafter, 0.01% of a yield-enhancing agent (manufactured by HIMO Corporation; NR12MLS) was added to the pulp, and papermaking was performed at a basis weight of 65 g/m ² with a Noble & Wood paper machine. In addition, the papermaking pH at this time was 4.5. Drying of the wet paper was performed at 100° C. for 80 seconds using a drum dryer.

(2) How to adjust the coating solution

Oxidized starch (MS3800 manufactured by Nippon Food Chemical Co., Ltd.) was diluted with water to a concentration of 10%, and gelatinized at 95° C., and the above-mentioned surface sizing agent was mixed with the gelatinized liquid to prepare a coating liquid. At this time, the solid content concentrations of the oxidized starch and the surface sizing agent in the coating solution were adjusted to the following values. Then adjust the coating solution to pH 8 with caustic soda or sulfuric acid, or adjust to pH 6 with sulfuric acid, then the coating solution with pH 8 and the coating solution with pH 6 can be prepared.

The solid content concentration of oxidized starch in the coating solution: 6%

Solid content concentration of surface sizing agent in coating solution: 0.2%

(3) Manufacture and evaluation of high-quality acidic paper

On the base paper made in the above (1), the coating solution prepared in the above (2) is coated with a size press to obtain an acidic high-quality paper. The resulting test paper was adjusted for 24 hours under constant temperature and humidity (20°C, 65% relative humidity) environment, and the STICKY HIT sizing degree (according to JIS P8122) and pen book sizing degree were measured (according to J TAPPI pulp test method No.12-76).

The evaluation results are shown in Table 2. Moreover, the higher the value of STICKY HIT sizing degree and pen writing leakage, the better it is.

(Test example 2) Evaluation with neutral high-quality paper

(1) Manufacture of base paper for neutral high quality

380 ml of pulp comminuted to Canadian Standard Freeness (9:1 hardwood to conifer pulp mix) was made into a 2.5% slurry to which was added 2% (absolute dry weight basis) of Calcium carbonate (manufactured by Okutama Industry Co., Ltd.; TP121S). To this, amphoteric starch (manufactured by National Starch Co., Ltd.; Cato3210) at 0.5% (on an absolute dry weight basis) relative to the pulp and 0.08% (on an absolute dry weight basis) of an alkyldiketene-based sizing agent (Japan Made by PMC; AS263), the pulp slurry was diluted to a concentration of 0.25% with dilution water of pH 7.5. Thereafter, 8% (absolute dry weight basis) of calcium carbonate (manufactured by Okutama Industry Co., Ltd.; TP121S) relative to the pulp and 0.01% of a yield enhancer (manufactured by HIMO Corporation; NR12MLS) relative to the pulp were added to the diluted pulp slurry. , and use Noble & Wood paper machine to make paper with the weight of 65g/m ² . In addition, the papermaking pH at this time was 7.5. Drying of the wet paper was performed at 100° C. for 80 seconds using a drum dryer.

(2) Preparation method of coating liquid

Oxidized starch (MS3800 manufactured by Nippon Food Chemical Co., Ltd.) was diluted with water to a concentration of 10%, and gelatinized at 95° C., and the above-mentioned surface sizing agent was mixed with the gelatinized liquid to prepare a coating liquid. At this time, the solid content concentrations of the oxidized starch and the surface sizing agent in the coating solution were adjusted to the following values. Then this coating solution is adjusted to pH8 with caustic soda or sulfuric acid, then the coating solution of pH8 can be prepared.

The solid content concentration of oxidized starch in the coating solution: 6%

Solid content concentration of surface sizing agent in coating solution: 0.2%

(3) Manufacture and evaluation of neutral high-quality paper

On the base paper produced in the above (1), the coating solution configured in the above (2) is coated with a size press to obtain a neutral high-quality paper. Adjust the humidity of the obtained test paper for 24 hours in a constant temperature and humidity environment (20°C, 65°C relative humidity), and measure the STICKY HIT sizing degree and pen writing leakage degree as in Test Example 1. The results are shown in Table 2.

(Test Example 3) Evaluation with inkjet recording paper

380 ml of pulp comminuted to Canadian Standard Freeness (hardwood to conifer pulp ratio of 9 to 1) was made into a 2.5% slurry to which 1% (absolute dry weight basis) was added to the pulp Calcium carbonate (manufactured by Okutama Industry Co., Ltd.; TP121S) and 5% talc powder (manufactured by Fuji TALC Industry Co., Ltd.: ND TALC). In this, 1.0% (absolute dry weight basis) of alum relative to pulp, 0.5% (absolute dry weight basis) of amphoteric starch (manufactured by National Starch Co., Ltd.; Cato3210) relative to pulp, and 0.3% (absolute dry weight basis) Weight basis) neutral paper with rosin-based sizing agent (manufactured by PMC in Japan; CC167), the pulp slurry was diluted to a concentration of 0.25% with dilution water of pH 7.5. Thereafter, 4% (absolute dry weight basis) of calcium carbonate (manufactured by Okutama Industry Co., Ltd.; TP121S) relative to the pulp and 0.01% of a yield enhancer (manufactured by HIMO Corporation; NR12MLS) relative to the pulp were added to the diluted pulp slurry. , and use Noble & Wood paper machine to make paper with a meter weight of 65g/m ² . In addition, the papermaking pH at this time was 7.5. Drying of the wet paper was performed at 100° C. for 80 seconds using a drum dryer.

(2) Preparation method of coating liquid

Oxidized starch (MS3800 manufactured by Nippon Food Chemical Co., Ltd.) was diluted with water to a concentration of 10%, and gelatinized at 95° C., and the above-mentioned surface sizing agent and salt were mixed in the gelatinized liquid to prepare a coating liquid. At this time, the solid content concentrations of the oxidized starch, the surface sizing agent, and the salt in the coating liquid were adjusted to the following values. Then this coating liquid is adjusted to PH8 with caustic soda or sulfuric acid, then can be modulated into the coating liquid of PH8.

Solid content concentration of oxidized starch in the coating liquid: 8%

Solid content concentration of surface sizing agent in coating solution: 0.2%

Solid content concentration of salt in the coating solution: 0.5%

(3) Manufacture of recording paper

On the base paper produced in the above (1), the coating solution prepared in the above (2) was coated with a size press to obtain a recording paper. The obtained test paper was conditioned for 24 hours in a constant temperature and humidity environment (20° C., 65% relative concentration).

(4) Evaluation of recording paper

The test paper obtained in the above (3) was conditioned for 24 hours in a constant temperature and humidity environment (20° C., 65% relative concentration), and the following inkjet suitability test was performed.

(Inkjet Suitability Test Method)

The evaluation of inkjet applicability was carried out by calendering the test paper obtained from the above-mentioned sizing effect test, and after adjusting the humidity for more than 24 hours in a constant temperature and humidity (20°C, 65% relative humidity) environment, using Canon Co., Ltd. ) to make Bubble Jet Printer BJ-220 JC II and proceed according to the following method. The results are shown in Table 3.

(a) Printing density test

β printing was carried out on the test paper, and the printing density of the β part was measured with a MACBASE ink densitometer. The larger the numerical value, the higher the printing density.

(b) Paper feathering test

Orthogonal straight lines and characters with a constant line width were printed on the test paper, and the bleed-out of the straight lines and outer lines of the characters was visually evaluated in five grades. A sample that did not bleed at all was set at 5, and a sample that bled ink and characters could not be recognized was set at 1. Kanai usually uses a printing quality of 4 or higher.

(c) Backside Penetration Test

β printing was performed on test paper, and the degree of ink bleeding on the back side of the β printed part was evaluated visually and on a 5-point scale. The sample with no ink bleed out on the back was set at 5, and the sample with the β portion completely showing back bleed was set at 1. Kanai usually uses a printing quality of 4 or higher.

(Test Example 4) Foaming test

(1) Preparation of test solution for evaluation of foamability

Oxidized starch (MS3800 manufactured by Nippon Food Chemical Co., Ltd.) was diluted with water to a concentration of 10%, gelatinized at 95°C, and the above-mentioned surface sizing agent and salt were mixed in the gelatinized liquid to prepare a coating liquid. At this time, the solid content concentrations of the oxidized starch, the surface sizing agent, and the salt in the coating liquid were adjusted to the following values.

The solid content concentration of oxidized starch in the coating solution: 5%

Solid content concentration of surface sizing agent in coating solution: 0.2%

Solid content concentration of salt in the coating solution: 0.5%

(2) Evaluation of foaming property of coating liquid

Put 600 grams of the coating solution formulated in (1) above into a foam measurement cell with an inner diameter of 7 cm and a length of 50 cm, and cycle through the following conditions to measure the height (mm) of the foam. The results are shown in Table 3.

The temperature of the coating liquid is 60°C, the flow rate of the circulation pump is 9 liters/minute, and the circulation time is 3 minutes.

In addition, in Table 3, the lower the height of the foam, the lower the foamability (the amount of foaming is small).

(Test Example 5) Mechanical Stability Test

50 g of the coating solution adjusted in (1) of the above (Test Example 4) was put into a cup, and a Maron stability test was performed for 10 minutes at a temperature of 60° C., a load of 20 kg, and a rotation speed of 800 rpm. Filter the generated aggregates with a 325-mesh metal mesh, measure the amount of precipitation relative to the total solid content, and express it as a percentage. The results are shown in Table 3.

(Test Example 6) Stability Test for Metal Ions

Dilute the surface sizing agent to a solid content of 0.2% with dilution water with a hardness of 700ppm (calculated as CaCO3) to prepare a dispersion. The change in the state of the dispersion liquid was observed, and a sample in which no change was observed was rated as ◯, a sample in which a slight turbidity occurred was rated as △, and a sample in which sediment was formed was rated as ×. The results are shown in Table 3.

It can be known from the evaluation results of acidic high-quality paper and neutral paper high-quality paper in Table 2 that the surface sizing agent of the embodiment has little influence on the pH change of the coating liquid, and the STICKY HIT sizing degree and pen writing leakage are relatively low. The surface sizing agents of Comparative Examples 1, 3, and 4 are better.

From the evaluation results of inkjet recording paper in Table 3, it can be seen that the surface sizing agents of Examples are better than the surface sizing agents of Comparative Examples 1, 3, and 4 in evaluations of printing density, paper feathering test, and back penetration.

As can be seen from the evaluation results in Table 3, the surface sizing agent of the embodiment has lower foamability than the surface sizing agents of all comparative examples, and the mechanical stability of the surface sizing agent of the embodiment is lower than that of all the surface sizing agents except for comparative example 5. The surface sizing agents of the examples are more excellent, and for the stability of metal ions, the surface sizing agents of the examples are more excellent than the surface sizing agents of all the comparative examples.

[Table 1] (one) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Dispersant before polymerization Type by weight Shellac 8 Shellac 12 Shellac 5 JS-22 JS-22 Shellac 12 Shellac 7 Type by weight JS-21 MS-601 Nonionic Hydrophilic Monomer Type by weight AAm8 AAm8 AAm10 AAm10 AAm5 AAm20 AAm10 anionic monomer Type by weight MAA2 AA2 MAA2 MAA7 hydrophobic monomer Type by weight St40 i BMA40 nBMA60 i BMA55 St50 i BMA40 nBMA70 Type by weight n BA60 n BA60 nBA40 i BA45 i BA50 n BA60 i BA30 Dispersant after polymerization Type by weight S-120 S-215 S-220 S-220 S-220 S-215 S-130 Type by weight Shellac 5 Shellac 7 Shellac 5 Solid content (%) 25.3 25.0 25.2 24.7 24.8 25.0 23.5

【Table 1】(Part 2) Example 8 Example 9 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Dispersant before polymerization Type by weight Shellac 13 Shellac 3 Shellac 8 Shellac 12 JS-22 S-150 Type by weight JS-21 Nonionic Hydrophilic Monomer Type by weight AAm12 AAm8 AAm8 anionic monomer Type by weight MAA2 MAA2 MAA2 MAA2 hydrophobic monomer Type by weight nBMA60 St40 St40 i BMA40 St50 St50 Type by weight nBA40 n BA60 n BA60 n BA60 i BA50 i BA50 Dispersant after polymerization Type by weight S-215 S-215 S-120 Solid content (%) 25.1 25.0 23.5 25.0 25.2 24.7

In addition, the abbreviations in the table represent the following substances.

AAm: acrylamide

MAA: methacrylic acid

AA: Acrylic

St: Styrene

iBMA: Isobutyl methacrylate

nBMA: n-butyl methacrylate

iBA: Isobutyl Acrylate

nBA: n-butyl acrylate

MS-60: ANTOX MS-60 (manufactured by Nippon Emulsifier Co., Ltd.) (reactive emulsifier having a methacryloyl group, having the following structural formula)

However, in the above formula, R represents an alkyl group, n represents an integer, and X represents an alkali metal such as sodium.

JS-2: ELEMINOL JS-2 (manufactured by Sanyo Chemical Industry) (a reactive emulsifier having an allyl group, having the following structural formula)

Shellac: N811 (manufactured by Gifu Shellac Co., Ltd.), all the shellacs in the table were 100% neutralized with KOH.

【Table 2】 Test example 1 Test example 2 Coating liquid pH8 Coating solution pH6 Coating liquid pH8 STICKYHIT sizing degree pen writing leakage STICKYHIT sizing degree pen writing leakage STICKYHIT sizing degree pen writing leakage Example 1 28 6 27 6 26 5 Example 2 29 6 26 5 26 5 Example 3 25 5 25 5 twenty three 5 Example 4 twenty two 4 20 4 19 4 Example 5 20 4 18 4 18 4 Example 6 19 4 17 4 18 4 Example 7 18 4 17 4 18 4 Example 8 18 4 17 4 17 4 Example 9 17 4 15 4 15 4 Comparative example 1 12 2 6 2 9 2 Comparative example 2 26 5 twenty four 5 twenty three 5 Comparative example 3 8 2 7 2 5 1 Comparative example 4 9 2 6 2 3 1 Comparative Example 5 twenty four 5 16 5 twenty one 3

【table 3】 Test example 3 Test example 4 Test example 5 Test example 6 Printing Density Feathering degree back penetration Foaming mechanical stability metal ion stability Example 1 1.34 6 6 19 <0.5% ○ Example 2 1.34 6 6 14 <0.5% ○ Example 3 1.33 6 6 twenty one <0.5% ○ Example 4 1.30 5 5 25 <0.5% ○ Example 5 1.29 5 5 40 <0.5% ○ Example 6 1.30 5 5 36 <0.5% ○ Example 7 1.28 5 5 30 <0.5% ○ Example 8 1.25 5 4 53 <0.5% ○ Example 9 1.24 4 4 49 <0.5% ○ Comparative example 1 1.17 2 2 74 1.3% x Comparative example 2 1.32 5 5 70 0.9% △ Comparative example 3 1.17 2 2 130 3.5% x Comparative example 4 1.15 2 2 90 1.0% △ Comparative Example 5 1.30 5 5 150 <0.5% x

Industrial availability

The surface sizing agent of the present invention is excellent in mechanical stability, low foaming property and storage stability, can improve the sizing performance of acidic paper to neutral paper, and is useful for information paper, especially inkjet paper. Excellent applicability, low foaming property of the coating solution, compatibility with other co-administered drugs and stability to dissolved metal ions.

Claims (5)

1. Cypres, it is characterized in that: in the presence of the alkali metal salt (a) of shellac, be selected from (methyl) acrylamide, at least a nonionic hydrophilic monomer (b) of the group that acrylonitrile and (methyl) hydroxyalkyl acrylate are formed and be selected from styrene derivative, and in the reactant liquor of at least a hydrophobic monomer (d) the polymerization gained of the group formed of (methyl) alkyl acrylate, mix the partially or completely corrective be selected from anionic property styrene-(methyl) acrylic acid series copolymer, and at least a macromolecule dispersing agent (e) of the group formed of polyvinyl alcohol makes.

2. Cypres, it is characterized in that: in the presence of the alkali metal salt (a) of shellac, be selected from (methyl) acrylamide, at least a nonionic hydrophilic monomer (b) of the group that acrylonitrile and (methyl) hydroxyalkyl acrylate are formed, be selected from acrylic acid, methacrylic acid, maleic acid, at least a anionic property monomer (c) of the group that fumaric acid is formed and be selected from styrene derivative, and in the reactant liquor of at least a hydrophobic monomer (d) the polymerization gained of the group formed of (methyl) alkyl acrylate, mix the partially or completely corrective be selected from anionic property styrene-(methyl) acrylic acid series copolymer, and at least a macromolecule dispersing agent (e) of the group formed of polyvinyl alcohol makes.

3. Cypres; it is characterized in that: in the presence of the reactive emulsifier with methacryl (f) of the alkali metal salt that does not comprise shellac (a); be selected from (methyl) acrylamide; at least a nonionic hydrophilic monomer (b) of the group that acrylonitrile and (methyl) hydroxyalkyl acrylate are formed and be selected from styrene derivative; and in the reactant liquor of at least a hydrophobic monomer (d) the polymerization gained of the group formed of (methyl) alkyl acrylate; mix the alkali metal salt (a) of shellac and be selected from the partially or completely corrective of anionic property styrene-(methyl) acrylic acid series copolymer, and at least a macromolecule dispersing agent (e) of the group formed of polyvinyl alcohol makes.

4. Cypres; it is characterized in that: in the presence of the reactive emulsifier with methacryl (f) of the alkali metal salt that does not comprise shellac (a); be selected from (methyl) acrylamide; at least a nonionic hydrophilic monomer (b) of the group that acrylonitrile and (methyl) hydroxyalkyl acrylate are formed; be selected from acrylic acid; methacrylic acid; maleic acid; at least a anionic property monomer (c) of the group that fumaric acid is formed and be selected from styrene derivative; and in the reactant liquor of at least a hydrophobic monomer (d) the polymerization gained of the group formed of (methyl) alkyl acrylate; mix the alkali metal salt (a) of shellac and be selected from the partially or completely corrective of anionic property styrene-(methyl) acrylic acid series copolymer, and at least a macromolecule dispersing agent (e) of the group formed of polyvinyl alcohol makes.

5. Cypres is characterized in that: comprise:

Alkali metal salt (a) with shellac, be selected from (methyl) acrylamide, at least a nonionic hydrophilic monomer (b) of the group that acrylonitrile and (methyl) hydroxyalkyl acrylate are formed and be selected from styrene derivative, and at least a hydrophobic monomer (d) of the group formed of (methyl) alkyl acrylate is as the polymer of repetitive, perhaps with described nonionic hydrophilic monomer (b), be selected from acrylic acid, methacrylic acid, maleic acid, at least a anionic property monomer (c) of the group that fumaric acid is formed and be selected from styrene derivative, and at least a hydrophobic monomer (d) of the group formed of (methyl) alkyl acrylate is as the polymer of repetitive;

Be selected from the partially or completely corrective of anionic property styrene-(methyl) acrylic acid series copolymer, and at least a macromolecule dispersing agent (e) of the group formed of polyvinyl alcohol.