KR101666273B1 - Styrene-butadiene latex and preparation method thereof - Google Patents

Abstract

One embodiment of the present invention is a semiconductor device comprising: a core; A first shell coated on the core; And a second shell coated on the first shell, wherein the second shell comprises a styrene-butadiene-based monomer mixture and a polymer of a polymer emulsifier.

Description

[0001] STYRENE-BUTADIENE LATEX AND PREPARATION METHOD THEREOF [0002]

One embodiment of the present invention relates to a styrene-butadiene latex and a method for producing the same.

In general, coated paper is produced by coating an inorganic pigment such as clay, calcium carbonate, aluminum hydroxide (Al (OH) ₃ ), titanium oxide (TiO ₂ ) In this case, natural binders such as casein and starch, and artificial binders such as polyvinyl alcohol and acrylic latex are used as an adhesive. In addition, various additives such as a dispersant, a thickener, and a water-proofing agent are used together. However, the largest proportion is also inorganic pigments and binders, which should be selected in the direction of obtaining a balanced coating material properties.

The most commonly used inorganic pigments are clay and calcium carbonate. The clay has a plate-like structure and has the advantage of obtaining high white glossy and printing gloss, but has a disadvantage of low fluidity and high binder requirement. On the other hand, there is a problem that calcium carbonate is excellent in fluidity, adhesive strength, ink-repellency, paper brightness, opacity and the like, while chemical stability of the coating solution to calcium cation is more required.

In recent years, paper manufacturers are increasing the paper coating speed with increasing the concentration of the solid content of the coating liquid in order to reduce the post-coating drying energy. However, as the coating speed increases, the shear force during coating increases, so stability and fluidity of the coating solution becomes more important at high shear. For this reason, efforts are being made to improve the stability of the coating liquid.

Since such a coating liquid is greatly affected by stability by latex, it is very important to improve the stability of the latex itself. In the case of the emulsifier contained in the latex, there may be differences depending on the functional group. Generally, as an emulsifier used in the latex, anionic emulsifier or anionic emulsifier having a functional group such as a sulfate or a sulfonate, Oxide-based non-ionic emulsifier, and the like. However, since the emulsifier is not adsorbed to the latex and is adsorbed, there is a problem that when the mechanical shear force is applied, the efficiency of imparting stability is deteriorated and the foam generation becomes severe.

Korean Patent No. 10-0553199

One embodiment of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a styrene-butadiene latex having improved stability and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a semiconductor device comprising: a core; A first shell coated on the core; And a second shell coated on the first shell, wherein the second shell provides a styrene-butadiene-based latex comprising a styrene-butadiene-based monomer mixture and a polymer of a polymer emulsifier.

In another embodiment of the present invention, there is provided a method of making a core comprising the steps of: a) preparing a core, b) coating the core with a first shell, and c) providing a styrene-butadiene- And coating the shell on the first shell. The present invention also provides a method for producing a styrene-butadiene latex.

In another embodiment of the present invention, there is provided a paper coating composition comprising an inorganic pigment and a binder, wherein the binder includes a styrene-butadiene latex.

In another embodiment of the present invention, there is provided a paper produced by applying the paper coating composition.

The styrene-butadiene-based latex according to an embodiment of the present invention may include a polymer emulsifier and may be polymerized to reduce bubbles and internal impurities, thereby improving the stability of the styrene-butadiene latex.

Also, the composition for paper coating comprising the styrene-butadiene latex may have excellent polymerization stability, and the problem of solidification can be greatly improved when the paper coating composition is coated at high speed on paper.

Furthermore, it is possible to provide a coated paper excellent in printability such as white paper gloss, print gloss, adhesive power, water resistance, and fountainability of the paper coated with the paper coating composition.

Hereinafter, the present invention will be described in more detail.

One embodiment of the present invention comprises a core, a first shell coated on the core, and a second shell coated on the first shell, wherein the second shell comprises a styrene-butadiene-based monomer mixture and a polymer of a polymeric emulsifier Styrene-butadiene-based latex.

The styrene-butadiene-based latex may contain a polymer emulsifier in the second shell to reduce bubbles and internal impurities, thereby improving the stability of the styrene-butadiene latex. Also, the composition for paper coating comprising the styrene-butadiene latex may have excellent polymerization stability, and the problem of solidification can be greatly improved when the paper coating composition is coated at high speed on paper.

Further, it is possible to provide a coated paper excellent in printing suitability such as white paper gloss, printing gloss, adhesive force, water resistance and fusing ability of the paper coated with the paper coating composition.

The styrene-butadiene latex may comprise a core, a first shell coated on the core, and a second shell coated on the first shell, wherein the core is selected from the group consisting of styrene, 1,3-butadiene, ethylenically unsaturated acid Monomers, and copolymerizable vinyl-based monomers.

The styrene may impart hardness and water resistance to the styrene-butadiene latex. The styrene may be included in 20 to 90 parts by weight of styrene relative to 100 parts by weight of the styrene-butadiene-based monomer mixture. Preferably 25 to 80 parts by weight, more preferably 30 to 75 parts by weight, 35 to 65 parts by weight or 40 to 50 parts by weight.

When the styrene content is less than 20 parts by weight, the hardness and water resistance of the styrene-butadiene-based latex may be decreased. When the styrene-butadiene latex is contained in an amount exceeding 90 parts by weight, And the film forming ability can be reduced. Accordingly, when the styrene content is within the above range, the adhesion and film forming ability of the styrene-butadiene latex can be improved.

The 1,3-butadiene may impart flexibility to the styrene-butadiene latex and may serve as a crosslinking agent. The 1,3-butadiene may be included in an amount of 5 to 70 parts by weight based on 100 parts by weight of the styrene-butadiene monomer mixture . Preferably 15 to 60 parts by weight, more preferably 20 to 50 parts by weight or 30 to 50 parts by weight.

When the content of 1,3-butadiene is less than 5 parts by weight, the styrene-butadiene latex may be too hard. When the content of the styrene-butadiene latex is more than 70 parts by weight, the adhesive strength and water resistance may be deteriorated. Therefore, when 1,3-butadiene is included in the above range, it is possible to impart appropriate flexibility to the styrene-butadiene latex and improve the adhesive strength and water resistance.

Wherein said ethylenically unsaturated monomer is selected from the group consisting of unsaturated carboxylic acid selected from methacrylic acid, acrylic acid, itaconic acid, crotonic acid, fumaric acid, and maleic acid; Or an unsaturated polycarboxylic acid alkyl ester containing at least one carboxyl group selected from itaconic acid monoethyl ester, fumaric acid monobutyl ester, and maleic acid monobutyl ester.

The ethylenic unsaturated acid monomer improves the adhesion of the styrene-butadiene latex and improves the stability of the styrene-butadiene latex particles.

The ethylenic unsaturated acid monomer may be included in an amount of 1 to 15 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the styrene-butadiene-based monomer mixture. More preferably 2 to 7 parts by weight. When the amount of the ethylenically unsaturated acid monomer is less than 1 part by weight, it may be difficult to improve the adhesion of the styrene-butadiene latex. When the amount of the ethylenic unsaturated acid monomer is more than 15 parts by weight, the styrene-butadiene latex particles are unstable, .

Based monomer which can be copolymerized together with the above-mentioned styrene, 1,3-butadiene and ethylenic unsaturated acid monomers, if necessary. The copolymerizable vinyl-based monomer may be included in an amount of 0 to 45 parts by weight based on 100 parts by weight of the styrene-butadiene-based monomer mixture.

Wherein the copolymerizable vinyl monomer is a vinyl cyanide monomer selected from acrylonitrile and methacrylonitrile; Unsaturated carboxylic acid alkyl esters selected from methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and butyl methacrylate; unsaturated carboxylic acid hydroxyalkyl esters selected from? -droxyethyl acrylate,? -hydroxypropyl acrylate,? -hydroxyethyl methacrylate; Unsaturated carboxylic acid amides and derivatives thereof selected from acrylamide, methacrylamide, itaconamide and maleamic acid amoamide; And an aromatic vinyl monomer selected from? -Methylstyrene, vinyltoluene, and p-methylstyrene; and at least one selected from the group consisting of?

Among the vinyl-based monomers capable of copolymerization, the vinyl cyanide monomer may improve print gloss and may be included in an amount of 1 to 15 parts by weight based on 100 parts by weight of the styrene-butadiene-based monomer mixture. Preferably 3 to 10 parts by weight.

When the amount of the vinyl cyanide monomer is less than 1 part by weight, the printing gloss may be significantly reduced. When the amount of the vinyl cyanide monomer is more than 15 parts by weight, it may be difficult to improve the hardness, film forming ability and stability of the styrene-butadiene latex. Therefore, when the vinyl cyanide monomer is included in the above range, the printing gloss can be improved.

The unsaturated carboxylic acid alkyl ester may impart appropriate hardness to the styrene-butadiene latex and improve the film forming ability. The unsaturated fatty acid alkyl ester may be contained in an amount of 1 to 20 parts by weight, preferably 2 to 15 parts by weight. More preferably 3 to 10 parts by weight.

When the unsaturated alkyl ester is contained in an amount of less than 1 part by weight, it may be difficult to impart a suitable hardness to the styrene-butadiene latex, and it may be difficult to improve the film forming ability. If it is contained in an amount exceeding 20 parts by weight, it may be difficult to improve the stability, water resistance and printing gloss of the styrene-butadiene latex.

The unsaturated carboxylic acid amide and its derivatives may improve the chemical stability, mechanical stability and water resistance of the styrene-butadiene latex, and may be included in an amount of 1 to 10 parts by weight. Preferably 1 to 5 parts by weight.

When the amount of the unsaturated carboxylic acid amide and the derivative thereof is less than 1 part by weight, it may be difficult to improve the stability and water resistance of the styrene-butadiene latex. When the amount of the unsaturated carboxylic acid amide and the derivative is more than 10 parts by weight, . ≪ / RTI >

The core may have an average particle size of 50-100 nm and the core gel content may be 70-98%.

A styrene-butadiene latex comprising a core according to one embodiment of the present invention, a first shell coated on the core, and a second shell coated on the first shell, wherein the first shell covers the core 20 to 90 parts by weight of styrene, 5 to 70 parts by weight of 1,3-butadiene, 1 to 15 parts by weight of an ethylenic unsaturated acid monomer, and 0 to 45 parts by weight of a copolymerizable vinyl monomer. The critical significance according to the content of styrene, 1,3-butadiene, ethylenically unsaturated acid monomer and copolymerizable vinyl monomer is the same as described in the core part.

The first shell may have an average particle size of from 90 to 150 nm, and the gel content may be from 70% to 98%.

In addition, the second shell covers the first shell, and may include a polymer of a styrene-butadiene-based monomer mixture and a polymer emulsifier.

The styrene-butadiene-based monomer mixture may include 20 to 90 parts by weight of styrene, 5 to 70 parts by weight of 1,3-butadiene, 1 to 15 parts by weight of an ethylenically unsaturated acid monomer, and 0 to 45 parts by weight of a copolymerizable vinyl monomer , And the critical significance according to the contents of styrene, 1,3-butadiene, ethylenic unsaturated acid monomer and copolymerizable vinyl monomer is the same as described in the core portion.

In addition, the styrene-butadiene latex may include a polymer emulsifier in the second shell, and the second shell may include a polymer emulsifier to reduce the foam of the styrene-butadiene latex and reduce the internal impurities, -Butadiene-based latex can be improved. In addition, the polymer chain of the polymer emulsifier can impart steric stability of the styrene-butadiene latex. Furthermore, the mechanical stability of the paper coating composition containing the styrene-butadiene-based latex can be increased by high-speed coating.

The polymer emulsifier may include a styrene-based monomer and a carboxylic acid-based ethylenically unsaturated monomer, and the styrene-based monomer may be selected from the group consisting of styrene,? -Methylstyrene,? -Ethylstyrene, p-methylstyrene, styrenesulfonic acid and vinyltoluene And the like.

The styrene-based monomer may be contained in an amount of 45 to 85% by weight based on the total amount of the polymer emulsifier. When the styrene-based monomer is contained in an amount of less than 45% by weight, the polymerization stability of the styrene-butadiene latex may be deteriorated by using a polymer emulsifier. When the styrene- It is difficult to dissolve in an aqueous solution, which may be difficult to use. Accordingly, when the styrene-based monomer is included in the above range, stable polymerization of the styrene-butadiene latex can be improved by using a polymer emulsifier together with stable use of the polymer emulsifier.

In addition, the polymer emulsifier may include the carboxylic acid-based ethylenically unsaturated monomer together with the styrene-based monomer. Specific examples of the carboxylic acid-based ethylenically unsaturated monomers include ethylenically unsaturated carboxylic acid monomers including acrylic acid, methacrylic acid, itaconic acid, maleic acid, and the like; Maleic anhydride, citraconic anhydride and the like, and unsaturated sulfonic acid monomers including styrene sulfonic acid, and the like.

The carboxylic acid-based ethylenically unsaturated monomer may be contained in an amount of 15 to 55% by weight based on the total amount of the polymer emulsifier. When the amount of the carboxylic acid-based ethylenically unsaturated monomer is less than 15% by weight, it is difficult to dissolve the polymer emulsifier in an aqueous alkaline solution having a pH of 7 or more. When the amount of the ethylenically unsaturated monomer is more than 55% by weight, the water resistance of the polymerized styrene-butadiene latex may be deteriorated. Therefore, when the carboxylic acid-based ethylenically unsaturated monomer is included in the above range, the solubility of the polymer emulsifier and the water resistance of the styrene-butadiene latex prepared using the polymer emulsifier can be improved.

As described above, the polymer emulsifier containing the styrene-based monomer and the carboxylic acid-based ethylenically unsaturated monomer may be included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the styrene-butadiene-based monomer mixture. Preferably 1 to 25 parts by weight, and more preferably 3 to 20 parts by weight.

When the polymer emulsifier is contained in an amount of less than 0.1 part by weight, the polymer emulsifier may not be able to exhibit the physical properties of the polymer emulsifier. Therefore, it may be insufficient to improve the viscosity and printing properties of the styrene-butadiene latex. If it is contained in an amount exceeding 30 parts by weight, the viscosity of the styrene-butadiene latex and the printing properties can be reduced.

The polymer emulsifier may be dissolved in an aqueous solution having a pH of 7 or more by mixing two or more kinds of styrene-based monomer and carboxylic acid-based ethylenically unsaturated acid monomer. The polymer emulsifier may be dissolved in an aqueous solution having a pH of 7 or more. To use an emulsifier, it may be possible to use an aqueous solution by ionizing a carboxylic acid-based ethylenically unsaturated monomer in an alkaline solution having a pH of 7 or more.

The glass transition temperature of the polymer emulsifier may be 80 to 150 ° C, and the weight average molecular weight of the polymer emulsifier may be 2,000 to 20,000.

The styrene-butadiene latex according to one embodiment of the present invention comprises a core, a first shell coated on the core, a second shell coated on the first shell, a styrene-butadiene-based monomer mixture of the second shell and a polymer emulsifier In addition to the polymer of the present invention.

The molecular weight modifier may control the molecular weight, gel content and gel structure of the styrene-butadiene latex, and specific examples thereof may include n-dodecyl mercaptan and t-dodecyl mercaptan.

The molecular weight modifier may be included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the styrene-butadiene-based monomer mixture. Preferably 0.2 to 5 parts by weight, and more preferably 0.5 to 2 parts by weight. If the amount of the molecular weight regulator is less than 0.1 parts by weight, the molecular weight, gel content, and gel structure may be insufficient to control the desired level. If the molecular weight regulator is included in an amount exceeding 10 parts by weight, the reaction rate and reaction stability may be deteriorated.

The above- 1 shell, and the average particle diameter of the second shell comprising the polymer of the styrene-butadiene-based monomer mixture and the polymer emulsifier may be 140 to 200 nm.

The glass transition temperature of the styrene-butadiene latex according to an embodiment of the present invention may be -30 to 70 ° C, preferably -30 to 50 ° C. More preferably -20 to 40 < 0 > C.

The particle diameter of the styrene-butadiene latex may be 50 to 300 nm, preferably 70 to 250 nm. More preferably 80 to 200 nm.

In addition, the gel content of the styrene-butadiene-based latex may be 50 to 95%, preferably 60 to 95%, more preferably 70 to 95%.

When the glass transition temperature, particle size and gel content of the styrene-butadiene-based latex are within the above ranges, the stability and fluidity of the styrene-butadiene latex can be improved and the ink drying speed, white glossy, print gloss, It is possible to improve printability such as growth.

Accordingly, the styrene-butadiene-based latex according to an embodiment of the present invention can be polymerized stably in a coating composition containing a styrene-butadiene latex by polymerizing the second shell with a polymer emulsifier, The problem of coagulation can be greatly improved when the coating composition is coated rapidly on paper. Further, by modifying the surface properties of the styrene-butadiene latex, it is possible to provide a coated paper excellent in printability such as ink drying speed, white glossy, print gloss, adhesive force, water resistance,

In another embodiment of the present invention, there is provided a method of making a core comprising the steps of: a) preparing a core, b) coating the core with a first shell, and c) providing a styrene-butadiene- And coating the shell on the first shell. The present invention also provides a method for producing a styrene-butadiene latex.

The styrene-butadiene latex may be prepared by preparing the core and then coating the core with the first to third shells. Other reaction conditions such as polymerization initiators, emulsifiers and electrolytes which are not specifically shown are the same as those of emulsion polymerization.

The core may mean seed latex, and the amount of the core may be 1 to 15 parts by weight based on 100 parts by weight of the total amount of the first shell and the second shell.

When the core is contained in an amount of less than 1 part by weight, the polymerization stability of the produced styrene-butadiene latex may be unstable. When the core is contained in an amount exceeding 15 parts by weight, the particle size of the styrene- Can greatly increase.

The polymer emulsifier contained in the second shell may be added in order to impart stability to the styrene-butadiene latex during the production of the styrene-butadiene latex. The polymer emulsifier may be added at the final stage of the polymerization of the styrene-butadiene latex The polymerization stability of the paper coating composition can be improved.

The polymer emulsifier contained in the second shell may be included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the styrene-butadiene-based monomer mixture. Preferably 1 to 25 parts by weight, and more preferably 3 to 20 parts by weight.

When the polymer emulsifier is contained in an amount of less than 0.1 part by weight, the polymerization stability may deteriorate upon polymerization with the styrene-butadiene-based monomer mixture, and further, the polymerization stability of the styrene-butadiene latex may be deteriorated. Further, it may be insufficient to improve the viscosity and printing properties of the styrene-butadiene latex. If it is contained in an amount exceeding 30 parts by weight, the viscosity of the styrene-butadiene latex and the printing properties can be reduced.

In another embodiment of the present invention, it is possible to provide a composition for paper coating comprising an inorganic pigment and a binder, wherein the binder includes the styrene-butadiene-based latex.

The inorganic pigment may be one or more kinds selected from the group consisting of clay, calcium carbonate, aluminum hydroxide (Al (OH) ₃ ) and titanium oxide (TiO ₂ ) Can be used without.

The binder may comprise a natural binder and an artificial binder. The natural binders may be casein and starch, and may be used without limitation as long as they are commonly used as natural binders.

The synthetic binder may include a styrene-butadiene latex according to an embodiment of the present invention, and may include 5 to 30 parts by weight based on 100 parts by weight of the inorganic pigment. If the amount is less than 5 parts by weight, the adhesive strength of the paper coating composition may be insufficient, and if it is more than 30 parts by weight, the adhesive strength may be reduced.

The paper may be prepared by applying the composition for paper coating according to an embodiment of the present invention. The paper coating composition may be calendered by calendering or the like.

Hereinafter, the present invention will be described more specifically by way of examples. However, the following examples are intended to aid understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

[Example 1]

(Preparation of Core)

A 10 l pressure reactor equipped with a stirrer, a thermometer, a condenser, a nitrogen gas inlet, a monomer, an emulsifier and a polymerization initiator so as to be continuously charged was substituted with nitrogen, and the following components were filled and the temperature was raised to 65 캜.

Styrene: 40 parts by weight

1,3-butadiene: 35 parts by weight

Methyl methacrylate: 12 parts by weight

Acrylonitrile: 8 parts by weight

Itaconic acid: 3 parts by weight

Acrylic acid: 2 parts by weight

Sodium dodecyldibenzenesulfonate: 4 parts by weight

t-Dodecylmercaptan: 0.15 part by weight

Sodium bicarbonate: 0.4 parts by weight

Ion-exchanged water: 420 parts by weight

1 part by weight of potassium persulfate as a polymerization initiator was added thereto, and the mixture was stirred for about 300 minutes to complete the polymerization. The obtained core had an average particle size of 70 nm, a conversion of 98%, and a gel content of 85% by weight.

(Preparation of first shell)

In order to coat the first shell on the prepared core, the core obtained in the core manufacturing process was added to the solid content based on 7 parts by weight of the solid content and 59 parts by weight of ion-exchanged water with respect to 100 parts by weight of the monomer combination of the first shell and the second shell in the reactor. After the temperature was raised to 80 ° C, the following components were continuously added for 100 minutes to polymerize.

Styrene: 11.50 parts by weight

1,3-butadiene: 20 parts by weight

Methyl methacrylate: 4 parts by weight

Acrylonitrile: 2 parts by weight

Itaconic acid: 1.0 part by weight

Acrylic acid: 1.5 parts by weight

Sodium dodecyldibenzenesulfonate: 0.18 part by weight

t-Dodecylmercaptan: 0.32 part by weight

Sodium bicarbonate: 0.16 parts by weight

Ion-exchanged water: 10 parts by weight

Potassium persulfate: 0.5 parts by weight

After all of the above components were added, the mixture was further stirred for 40 minutes to complete the polymerization. The first shell thus polymerized was found to have an average particle size of 119 nm and a conversion of 90%.

(Preparation of Second Shell)

In order to coat the first shell with the second shell, the temperature of the reactor in which the latex polymerized to the first shell was filled was maintained at 80 DEG C, 2 parts by weight of ammonia (20%) solution was added, After further stirring, the following components were continuously added for 150 minutes to polymerize.

Styrene: 27.3 parts by weight

1,3-butadiene: 20 parts by weight

Methyl methacrylate: 6 parts by weight

Acrylonitrile: 3 parts by weight

Polymer Emulsifier: 3.7 parts by weight

Sodium dodecyldibenzenesulfonate: 0.17 parts by weight

t-Dodecylmercaptan: 0.48 part by weight

Sodium bicarbonate: 0.24 parts by weight

Ion-exchanged water: 15 parts by weight

Potassium persulfate: 0.6 parts by weight

After all of the above components were added, the polymerization was completed by further stirring for 200 minutes. The final latex polymerized to the second shell had an average particle size of 173 nm and a conversion of 98%. The gel content was 82% by weight and the glass transition temperature (Tg) was -3 to 3 占 폚.

[Example 2]

Except that 23.5 parts by weight of styrene, 7.5 parts by weight of a polymer emulsifier and 0.07 part by weight of sodium dodecyldibenzenesulfonate were used in the production process of the second shell of Example 1 above.

The final latex polymerized to the second shell had an average particle diameter of 167 nm and a conversion of 98%. The gel content was 82% by weight and the glass transition temperature (Tg) was -3 to 3 占 폚.

[Example 3]

Except that 16 parts by weight of styrene and 15 parts by weight of a polymer emulsifier were used in the production process of the second shell of Example 1 and sodium dodecyldibenzenesulfonate was not used. .

The final latex thus polymerized to the second shell had an average particle diameter of 159 nm and a conversion of 99%. The gel content was 83% by weight and the glass transition temperature (Tg) was -3 to 3 占 폚.

[Example 4]

15 parts by weight of the core and 15 parts by weight of ion-exchanged water were charged to 100 parts by weight of the sum of the monomers of the first shell and the second shell in the production process of the first shell of Example 1, , The polymerization was carried out in the same manner as in Example 1 above.

The final latex thus polymerized to the second shell had an average particle size of 125 nm, a conversion of 98%, a gel content of 85% and a glass transition temperature (Tg) of -3 to 3 ° C.

[Example 5]

Except that 23.5 parts by weight of styrene, 7.5 parts by weight of a polymer emulsifier, and 0.07 parts by weight of sodium dodecylbenzenesulfonate were used in the second shell manufacturing process of Example 4, respectively.

The final latex thus polymerized to the second shell had an average particle size of 121 nm and a conversion of 98%. The gel content was 86% by weight and the glass transition temperature (Tg) was -3 to 3 占 폚.

[Example 6]

Except that 16 parts by weight of styrene and 15 parts by weight of a polymer emulsifier were used in the second shell production process of Example 4 and sodium dodecyldibenzenesulfonate was not used.

The final latex thus polymerized to the second shell had an average particle size of 119 nm, a conversion of 99%, a gel content of 86% by weight, and a glass transition temperature (Tg) of -3 to 3 캜.

[Comparative Example 1]

The same procedure as in Example 1 was carried out except that 28.5 parts by weight of styrene, 2.5 parts by weight of acrylic acid and 0.27 parts by weight of sodium dodecyldibenzenesulfonate were used in the second shell manufacturing process of Example 1 and the polymer emulsifier was not used. .

The final latex polymerized to the second shell had an average particle diameter of 171 nm and a conversion of 98%. The gel content was 81% by weight and the glass transition temperature (Tg) was -1.3 ° C.

[Comparative Example 2]

The same procedure as in Example 4 was carried out except that 28.5 parts by weight of styrene, 2.5 parts by weight of acrylic acid and 0.27 parts by weight of sodium dodecyldibenzenesulfonate were used in the second shell manufacturing process of Example 4 and the polymer emulsifier was not used. .

The final latex thus polymerized to the second shell had an average particle size of 126 nm, a conversion of 99%, a gel content of 84% by weight, and a glass transition temperature (Tg) of -1.3 캜.

[Experimental Example 1]

1. Determination of the amount of impurities in the latex

To measure the polymerization stability of the latex, the latex was passed through 150 mesh, 200 mesh, and 325 mesh, respectively. The amount of the impurity was calculated on the basis of the solid content.

2. Measurement of the amount of impurities in the reactor

After completion of the polymerization, the internal scale of the reactor was scratched and the weight was measured.

3. Measurement of bubble generation of latex

10 g of the impregnated latex was put into a measuring cylinder together with 10 g of ion-exchanged water, the cap was closed, and the process of inverting upside down at a constant speed was repeated 50 times to measure the height at which the foam was formed.

The measurement results of the above items 1 to 3 are shown in [Table 1].

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 150mesh
(ppm) 36 12 19 69 17 31 105 215 200mesh
(ppm) 35 14 20 41 12 24 86 159 325mesh
(ppm) 49 17 34 59 22 12 101 181 inside
impurities
(scale, g) 43 27 15 52 25 16 153 295 bubble
(mm) 45 39 35 41 35 32 55 60

As shown in Table 1, the styrene-butadiene-based latexes of Examples 1 to 6 including the polymer emulsifier had a higher content of impurities in the styrene-butadiene latex than in Comparative Examples 1 and 2, It was confirmed that the amount of impurities inside was small.

As a result of comparing the degree of foam generation, it was confirmed that the latex of Examples 1 to 6 produced less bubbles.

As a result, it can be seen that the styrene-butadiene-based latex according to one embodiment of the present invention improves the stability of the latex by reducing the foam of the latex and reducing the internal impurities by including the polymer emulsifier.

[Experimental Example 2]

(Preparation of Paper Coating Solution)

In order to compare and evaluate the latexes of Examples 1 to 6 and Comparative Examples 1 and 2, a paper coating solution was prepared as in the following prescription.

First class clay: 20 parts by weight

Calcium carbonate: 80 parts by weight

Latex: 10 parts by weight

Thickening agent: 0.1 part by weight

Other additives: 1.2 parts by weight

The ion-exchanged water was added so that the solid content of the coating liquid was 67%.

1. Stability measurement of coating liquid

In order to comprehensively measure the chemical, mechanical and thermal stability, the coating liquid was stirred at a temperature of 85 ° C for 20 minutes using a Maron Tester, and the resulting coagulum was measured by # 325 mesh.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 stability
(ppm) 162 105 57 191 102 54 730 921

The stability measured by the Maron Tester means that the larger the value, the higher the content of the solidification product and the poorer the stability. As shown in the above Table 2, the composition for paper coating of Examples 1 to 6 had a lower solidified content and a much higher stability of 4 to 17 times than the paper coating compositions of Comparative Examples 1 and 2 Respectively.

Furthermore, since the composition for paper coating including the styrene-butadiene latex of the present invention has excellent polymerization stability and the content of the solidified material is low, the problem of solidification can be greatly improved when the composition for paper coating is coated at high speed on paper Able to know.

[Experimental Example 3]

(Making paper coated with composition for paper coating)

The paper coating composition was coated under the following conditions to obtain paper.

Coating: 15 g / m ² coating with rod manual coating (Rod Coating, No 6)

Drying: Oven, 105 ℃, 30 seconds

Calendars: Super Calendars, 60 ℃, 60kg / cm, 4m / min, 2 passes

Origin: Commercial land (72gsm basis)

1. Blank gloss measurement

Various parts of the coated paper were measured using an optical gloss meter (HUNTER type, 75 ° gloss) to obtain an average value.

2. Print gloss measurement

The coated paper was printed on an RI press and after 24 hours, it was measured in the same manner as the white glossy.

3. Adhesion measurement

The coated paper was printed several times on an RI press, and the degree of scraping was visually judged by the five-point method. The higher the score, the better the adhesive strength. The ink was measured using the tack values 10, 12 and 13, respectively, and the average value was obtained.

4. Water resistance measurement

In the RI press, wetting water was added using a Morton roll and then printed, and the extent of the peeling was measured in the same manner as the above adhesive force. And printing was performed once using ink of Tack Value 10 and then measured.

5. Measurement of adhesion

The degree of ink transfer was measured by adding wet water in an RI press after printing. The low tack value ink is used to prevent tearing, and the higher the score, the higher the tackling ability.

The results of the measurements 1 to 5 are shown in Table 3 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 White glossy 69 69 71 70 69 71 68 67 Print gloss 82 84 84 83 85 86 80 81 Adhesion 4.0 4.1 4.0 4.1 4.3 4.2 3.7 3.9 Water resistance 4.5 4.4 4.2 4.4 4.4 4.2 3.8 3.7 Development 4.0 4.2 4.2 4.0 4.2 4.2 3.5 3.7

As shown in the above Table 3, the paper coated with the paper coating composition of Examples 1 to 6 had a white glossy 1 to 4, a printed gloss 1 to 6, an adhesive strength of 0.2 to 4, 0.5, the water resistance of 0.4 to 0.7, and the improvement of the adhesion by about 0.3 to 0.7.

Further, it has been confirmed that the printability of the paper coated with the composition for paper coating according to one embodiment of the present invention, such as white glossy, printing gloss, adhesive strength, water resistance and fusing ability, is improved.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will readily appreciate that many suitable modifications and variations are possible in light of the above teachings. Accordingly, all such modifications and variations as fall within the scope of the present invention should be considered.

Claims (18)

core; A first shell coated on the core; And a second shell coated on the first shell,
Wherein the core comprises styrene, 1,3-butadiene and ethylenically unsaturated acid monomers,
Wherein the first shell comprises styrene, 1,3-butadiene and an ethylenically unsaturated acid monomer,
Wherein the second shell comprises a polymer of a styrene-butadiene-based monomer mixture and a polymer emulsifier,
Wherein the polymer emulsifier comprises a styrene-based monomer and a carboxylic acid-based ethylenically unsaturated monomer.
The method according to claim 1,
Wherein the core comprises 20 to 90 parts by weight of styrene, 5 to 70 parts by weight of 1,3-butadiene, 1 to 15 parts by weight of an ethylenically unsaturated acid monomer, and 0 to 45 parts by weight of a copolymerizable vinyl monomer. -Butadiene latex.
The method according to claim 1,
Wherein the core has an average particle size of 50 to 100 nm.
The method according to claim 1,
Wherein the first shell comprises 20 to 90 parts by weight of styrene, 5 to 70 parts by weight of 1,3-butadiene, 1 to 15 parts by weight of an ethylenically unsaturated acid monomer, and 0 to 45 parts by weight of a copolymerizable vinyl monomer Styrene-butadiene-based latex.
The method according to claim 1,
Wherein the first shell has an average particle size of 90 to 150 nm.
The method according to claim 1,
Wherein the styrene-butadiene-based monomer mixture comprises 20 to 90 parts by weight of styrene, 5 to 70 parts by weight of 1,3-butadiene, 1 to 15 parts by weight of an ethylenic unsaturated acid monomer, and 0 to 45 parts by weight of a copolymerizable vinyl monomer Styrene-butadiene-based latex.
The method according to claim 1,
Wherein the polymer emulsifier comprises 45 to 85% by weight of a styrene-based monomer and 15 to 55% by weight of a carboxylic acid-based ethylenically unsaturated monomer.
The method of claim 7,
Wherein the styrene-based monomer comprises at least one member selected from the group consisting of styrene,? -Methylstyrene,? -Ethylstyrene, p-methylstyrene, styrene sulfonic acid and vinyltoluene. .
The method of claim 7,
The carboxylic acid-based ethylenically unsaturated monomer includes an ethylenically unsaturated carboxylic acid monomer including acrylic acid, methacrylic acid, itaconic acid, maleic acid, and the like; Unsaturated sulfonic acid monomers including polycarboxylic acid anhydrides including maleic anhydride and citraconic anhydride and styrene sulfonic acid and the like; and styrene-butadiene-based latexes containing at least one member selected from the group consisting of .
The method according to claim 1,
Wherein the polymer emulsifier is dissolved in an aqueous solution having a pH of 7 or more.
The method according to claim 1,
Wherein the polymer emulsifier has a glass transition temperature of 80 to 150 ° C.
The method according to claim 1,
Wherein the polymer emulsifier has a weight average molecular weight of 2,000 to 20,000.
The method according to claim 1,
Wherein the second shell has an average particle diameter of 140 to 200 nm.
a) preparing a core comprising styrene, 1,3-butadiene and an ethylenically unsaturated acid monomer;
b) coating said core with styrene, 1,3-butadiene and ethylenically unsaturated acid monomers to coat said first shell; And
c) coating the first shell with a second shell comprising a polymer of a styrene-butadiene-based monomer mixture and a polymer emulsifier;
Lt; / RTI >
The method for producing a styrene-butadiene latex according to claim 1, wherein the polymer emulsifier comprises a styrene-based monomer and a carboxylic acid-based ethylenically unsaturated monomer.
15. The method of claim 14,
Wherein the amount of the core is 1 to 15 parts by weight based on 100 parts by weight of the first shell and the second shell.
15. The method of claim 14,
Wherein the polymer emulsifier is contained in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the styrene-butadiene-based monomer mixture.
An inorganic pigment, and a binder,
And a styrene-butadiene-based latex according to claim 1 as the binder.
A paper produced by applying the paper coating composition of claim 17.