JP3475969B2 - Copolymer resin emulsion, method for producing the same, and composition for moisture-proof processing - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolymer resin emulsion, and more particularly to a moisture-proof composition for forming a moisture-proof layer by coating or impregnating a paper or a non-woven fabric. .

[0002]

2. Description of the Related Art Conventionally, moisture-proof papers include moisture-proof coated papers obtained by coating a base paper with a polymer composition containing vinylidene chloride, polyethylene laminated papers and the like.

Although these moisture-proof papers are good in terms of moisture-proof performance, coating with a polymer composition containing vinylidene chloride requires pretreatment of the base paper, or incineration and disposal of vinylidene chloride-coated paper. Hazardous gas is generated by halogen, which is an environmental problem. Further, when polyethylene laminated paper is used, good moistureproofness can be expressed at low cost, but it cannot be recovered as waste paper, which has recently become a social problem.

As described above, all of the moisture-proof papers have problems, and the development of alternative moisture-proof papers is urgent. As a technique for this purpose, Japanese Patent Publication No. 55-22597 discloses a technique for coating a blend of 100 parts by weight of butadiene-based latex with 5 to 200 parts by weight of a wax to obtain a moisture-proof paper.

However, since this technique uses wax, it has a problem of "slip" when stacking processed papers and a problem of printability when printing on the processed papers. As for moisture resistance, it is difficult to obtain moisture resistance comparable to that of polyethylene laminated paper when applied to paper with a low coating amount.

A technique has also been proposed in which a wax is blended with an acrylic emulsion and coated on a cardboard to produce a moisture-proof paper (Japanese Patent Publication No. 1671/1990). It is inferior to a composition using latex as a base resin.

Therefore, at present, the paper industry and processing agent manufacturers are developing emulsion type coating agents capable of imparting moisture resistance comparable to that of polyethylene laminated paper with a low coating amount.

[0008]

DISCLOSURE OF THE INVENTION The present invention comprises a copolymer resin emulsion capable of imparting a high moisture proof performance (JIS Z0208) comparable to that of polyethylene laminated paper, a process for producing the same, and this copolymer resin emulsion. It is intended to provide a composition for moisture-proof processing.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors paper-coated a resin emulsion prepared by mixing a fatty acid ester compound and a butadiene latex at a specific ratio. As a result, they have found that they exhibit high moisture-proof performance comparable to polyethylene laminated paper, and have completed the present invention.

That is, in the present invention, the reactive emulsifier is added to 0.1
To 1 part by weight of a butadiene-based latex and a fatty acid ester compound obtained by reacting a fatty acid with an alcohol in a weight ratio of 100: 0.1-5. The present invention provides an emulsion, a method for producing the same, and a moisture-proofing composition using the same.

The fatty acid constituting the fatty acid ester of the present invention is a higher fatty acid having 6 or more carbon atoms, and among them, stearic acid is preferable. The alcohol constituting the fatty acid ester is a higher alcohol having 6 or more carbon atoms. The higher alcohol preferably has 16 or more carbon atoms in consideration of water resistance.

The fatty acid ester may be in the form of a powder, an emulsified type, or the like, but the emulsified type is preferred in view of workability in compounding.

The fatty acid ester is used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the butadiene latex. If the fatty acid ester is used in an amount of 0.1 parts by weight or less, or 5 parts by weight or more, it becomes difficult to impart high moisture resistance.

The butadiene-based latex of the present invention includes SBR (styrene-butadiene) and MBR (MMA).
-Butadiene), NBR (acrylonitrile-butadiene), and all polymer aqueous dispersions containing butadiene. Among these, in order to obtain high moistureproof performance,
SBR and MBR are preferred.

The butadiene type latex is produced by reacting butadiene with an ethylenically unsaturated monomer copolymerizable therewith. Examples of the ethylenically unsaturated monomer copolymerizable with butadiene include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, and acrylic. Acrylic acid alkyl ester and methacrylic acid exemplified by acid pentyl, pentyl methacrylate, hexyl acrylate, hexyl methacrylate, heptyl acrylate, heptyl methacrylate, octyl acrylate, octyl methacrylate, octadecyl acrylate, octadecyl methacrylate, etc. Acid acrylic ester; styrene, α
-Methylstyrene, vinyltoluene, chlorostyrene,
Ethylenically unsaturated aromatic monomers represented by 2,4-dibromostyrene and the like; unsaturated nitriles such as acrylonitrile and methacrylonitrile; acrylic acid, methacrylic acid, crotonic acid, maleic acid and its anhydride, fumaric acid, Itaconic acid, and unsaturated dicarboxylic acid monoacyl esters, for example, ethylenically unsaturated carboxylic acids such as monomethyl maleate, monoethyl fumarate, mono-n-butyl itaconate; vinyl esters such as vinyl acetate, vinyl propionate; vinylidene chloride, Vinylidene halides such as vinylidene bromide; hydroxyalkyl esters of ethylenically unsaturated carboxylic acids such as acrylate-2-hydroxyethyl, acrylate-2-hydroxypropyl, methacrylate-2-hydroxyethyl; glycidyl acrylate, Me Glycidyl esters of ethylenically unsaturated carboxylic acids such as glycidyl acrylate and radical-polymerizable monomers such as acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-butoxymethylacrylamide, diacetoneacrylamide Is mentioned.

These compounds are important compounds generally used for the purpose of imparting appropriate hardness to the latex film and improving adhesion, dispersibility, mechanical stability and freeze stability. The minimum film forming temperature (MFT) of the latex is preferably 0 ° C. or lower in consideration of the film forming property, but is not limited to these conditions.

As the type of emulsifier for the butadiene latex used in the present invention, it is essential to use a reactive emulsifier in consideration of the reactivity of the moisture-proof latex. Examples of reactive emulsifiers include commercially available sodium styrene sulfonate, sodium vinyl sulfonate, and emulsifiers having various ethylenically unsaturated groups. Among these, compounds having the following structural formulas shown in JP-A-58-203960 are most preferable.

[0018]

[Chemical 1]

(In the formula, R is an alkyl group having 12 carbon atoms or 18 carbon atoms in which one of hydrogen atoms is replaced by a fluorine atom.
Represents an alkyl group, and M represents Na or NH ₄ . ) The amount of the reactive emulsifier used is preferably 0.1 to 1 part by weight based on 100 parts by weight of the butadiene-based latex. Even if a butadiene-based latex containing 1 part by weight or more of a reactive emulsifier is used in combination with a fatty acid ester compound, it becomes difficult to exhibit high moisture resistance.

Production of the copolymer resin emulsion of the present invention
In doing so, the above-mentioned butadiene and butadiene
Add an emulsifier to the polymerizable ethylenically unsaturated monomer mixture.
Under the condition of using 0.1 to 1 part by weight, free radical generation
Add a biocatalyst and polymerize at 50-80 ° C.
Yes. As the free radical generating catalyst, for example, KPS
(K ₂S₂O₈), APS ((NH_Four)₂S₂O₈), Peroxidation
Aqueous catalyst such as hydrogen, t-butyl hydroperoxide
And oily catalysts such as cumene hydroperoxide
To be

Additives usually used in radical polymerization, such as chain transfer agents, ethylenediaminetetraacetic acid, pH
Alkaline materials for conditioning can be used if desired.
The obtained butadiene-based latex having a reactive emulsifier content of 0.1 to 1 part by weight is concentrated to a required solid content and used by a method such as stripping.

As a method of combining the fatty acid ester compound and the latex, the fatty acid ester compound may be blended with the latex, or butadiene and an ethylenic monomer mixture copolymerizable with butadiene may be reacted in the presence of the fatty acid ester compound. You may polymerize with a strong emulsifier.

The above-mentioned copolymer resin emulsion of the present invention can reduce the amount of the fatty acid ester compound used for obtaining the same moisture-proof property, and since it has less bleeding, it has the advantage of not impairing printability.

The copolymer resin emulsion of the present invention is applied to paper or non-woven fabric as a moisture-proofing composition obtained directly by various coaters or by blending with various fillers, or impregnated into paper or non-woven fabric by an impregnation machine, A wide variety of processing methods such as size press processing to adhere to paper can be applied.

As a coating amount, it is preferable that the coating amount be as low as 10 g / m ² or less in view of cost and recovery, but if it is 2 g / m ² or less, it is difficult to achieve high moisture resistance. . It is preferably coated at 3 to 5 g / m ² .

The target substrate can be used for paper, paperboard, nonwoven fabric, fiber substrate and the like.

[0027]

EXAMPLES The present invention will be described below with reference to synthesis examples and examples. All parts and% in the examples are based on weight.

Synthesis Example 1 120 parts of water, 0.1 part of sodium hydroxide and 0.5 part of reactive emulsifier S-180 (unsaturated alkylsulfate, manufactured by Kao Corporation) were placed in a pressure resistant polymerization vessel equipped with a stirrer. , 0.1 parts of ethylenediaminetetraacetic acid, 40 parts of styrene, 52 parts of butadiene, 3 parts of acrylic acid and 0.1 part of t-dodecyl mercaptan were charged, stirring was started, and the reaction temperature was raised to 60 ° C. When the temperature in the polymerization vessel reached 60 ° C., 0.1 part of ammonium persulfate was added to start the reaction. After 7 hours, when the polymerization rate reached 98%, cooling was performed. The obtained latex had a polymerization rate of 98.6%. Next, the pH of the latex was adjusted to 9.0 with 25% aqueous ammonia, and then steam distillation was performed to obtain an SBR latex (A) having a solid content of 50.1% and an emulsifier content of 1% or less.

Synthesis Example 2 110 parts of water, 0.7 part of reactive emulsifier S-180, 0.1 part of ethylenediaminetetraacetic acid, 50 parts of methyl methacrylate and 48 parts of butadiene were placed in a pressure polymerization vessel equipped with a stirrer. , 2 parts of itaconic acid and 0.3 part of t-dodecyl mercaptan were added, stirring was started, and the reaction temperature was 50 ° C.
The temperature was raised to. When the temperature in the polymerization vessel reached 50 ° C., 0.1 part of sodium persulfate was added to start the reaction. After 6 hours, cooling was performed when the polymerization rate reached 98%. The obtained latex had a polymerization rate of 99.6%. Then 2
The pH of the latex was adjusted to 9.0 with 5% aqueous ammonia, and then steam distillation was performed to obtain an MBR latex (B) having a solid content of 48.0% and an emulsifier content of 1% or less.

Synthesis Example 3 120 parts of water, 0.1 part of sodium hydroxide and 1.5 parts of Neoperex F-25 (sodium alkylbenzene sulfonate, manufactured by Kao Corporation) were placed in a pressure resistant polymerization vessel equipped with a stirrer. 0.1 parts ethylenediaminetetraacetic acid, 40 parts styrene, 52 parts butadiene, 3 parts acrylic acid,
0.1 part of t-dodecyl mercaptan was charged, stirring was started, and the reaction temperature was raised to 60 ° C. When the temperature in the polymerization vessel reached 60 ° C., 0.1 part of ammonium persulfate was added to start the reaction. After 6 hours, cooling was performed when the polymerization rate reached 98%. The obtained latex has a polymerization rate of 9
It was 8.6%. Then, the pH of the latex was adjusted to 9.0 with 25% aqueous ammonia, and then SB was added by steam distillation to obtain an emulsifier content of 1% or more with a solid content of 49.7%.
R latex (C) was obtained.

Examples 1 to 6 As the latex, latexes (A) to (B) obtained in Synthesis Examples 1 to 2 were mixed with fatty acid ester emulsions as shown in Table 1.
Compounded within the range shown in. The obtained copolymer resin emulsion was coated on a commercially available high-quality paper (basis weight 70 g / m ² ) with a coating amount of about 6 g / m ² by Meyer lot and dried in a hot air dryer at 120 ° C. for 1 minute. did. With respect to the processed paper thus obtained, the coating amount and the moisture vapor permeability (cup method at 20 ° C. and 90% humidity under constant temperature and constant humidity conditions) according to JIS Z0208 were measured.

The results are shown in Table 1. Especially the emulsifier content is 1
It can be seen that the paper coated with the composition in which the fatty acid ester compound is mixed with the latex of not more than 10% exhibits good moisture resistance.

Examples 7 to 8 120 parts of water, 0.1 parts of sodium hydroxide and 0 parts of reactive emulsifier S-180 in a pressure resistant polymerization vessel equipped with a stirrer, the amount of fatty acid ester emulsion shown in Table 2 were used. .5 copies,
0.1 parts ethylenediaminetetraacetic acid, 40 parts styrene
Parts, 52 parts of butadiene, 3 parts of acrylic acid and 0.1 part of t-dodecyl mercaptan were charged, stirring was started, and the reaction temperature was raised to 60 ° C. When the temperature in the polymerization vessel reached 60 ° C., 0.1 part of ammonium persulfate was added to start the reaction. After 7 hours, when the polymerization rate reached 98%, cooling was performed. The obtained latex had a polymerization rate of 98.6%. Then, the pH of the latex is adjusted with 25% aqueous ammonia.
Was adjusted to 9.0, and then steam-distilled to obtain a copolymer resin emulsion in which the emulsifier content was 1% or less and the solid contents containing the fatty acid ester compound were 49.9% and 50.1%, respectively. It was

The copolymer emulsion obtained above was coated with a Mayer lot at a coating amount of about 3 g / m ² and dried in a hot air drier at 120 ° C. for 1 minute. With respect to the processed paper thus obtained, the coating amount and the moisture vapor permeability (cup method at 20 ° C. and 90% humidity under constant temperature and constant humidity conditions) according to JIS Z0208 were measured. The results are shown in Tables 1 and 2. Since the values shown here are comparable to those of polyethylene laminated paper as in Example 1, it can be seen that the paper coated with this composition exhibits even better moisture resistance.

Comparative Examples 1 to 17 Latexes (A) to (C) obtained in Synthesis Examples 1 to 3 and commercial SBR (solid content 50.0%, emulsifier content 1 part by weight or more) and commercial MBR, respectively, for comparison. (Solid content 48.2
%, An emulsifier amount of 1 part by weight or more) and a commercial acrylic emulsion (solid content: 45.1%, emulsifier amount of 1 part by weight or more) were mixed with the fatty acid ester emulsion in the range shown in Table 3. Each of the obtained copolymer resin emulsions was applied to a commercially available high-quality paper (basis weight 70 g / m ² ) with a coating amount of about 6 g / m ² by means of a Meyer lot, and was applied in a hot air drier 12
It was dried at 0 ° C for 1 minute. With respect to the processed paper thus obtained, the coating amount and the moisture vapor permeability (cup method at 20 ° C. and 90% humidity under constant temperature and constant humidity conditions) according to JIS Z0208 were measured. A commercially available polyethylene laminated paper was also included in the measurement for comparison. The results are shown in Table 3.

From this table, the moisture-proof value of the latex containing no fatty acid ester compound was lower than that obtained in Examples 1 to 8, and it cannot be used as a moisture-proof paper alternative to polyethylene laminated paper in terms of moisture-proof property. I understand. Further, it is understood that the latex is superior in the effect of the fatty acid ester compound on the moisture resistance.

Comparative Examples 18 to 19 In a pressure resistant polymerization vessel equipped with a stirrer, 120 parts of water, 0.1 parts of sodium hydroxide in an amount of fatty acid ester emulsion shown in Table 4, reactive emulsifier S-180 ( (Kao Corporation) 1.5 parts, ethylenediamine tetraacetic acid 0.1
Parts, 40 parts of styrene, 52 parts of butadiene, 3 parts of acrylic acid and 0.1 part of t-dodecyl mercaptan were charged, stirring was started, and the reaction temperature was raised to 60 ° C. When the temperature in the polymerization vessel reached 60 ° C., 0.1 part of ammonium persulfate was added to start the reaction. After 7 hours, when the polymerization rate reached 98%, cooling was performed. The obtained latex had a polymerization rate of 98.6%. Next, the pH of the latex was adjusted to 9.0 with 25% ammonia water, and then steam distillation was carried out to obtain solid contents of the emulsifier content of 1% or more and the fatty acid ester compound blended at 50.3% and 5 respectively.
A 0.0% copolymer emulsion was obtained.

The copolymer emulsion obtained above was coated with a Mayer lot at a coating amount of about 3 g / m ² and dried in a hot air dryer at 120 ° C. for 1 minute. With respect to the processed paper thus obtained, the coating amount and the moisture vapor permeability (cup method at 20 ° C. and 90% humidity under constant temperature and constant humidity conditions) according to JIS Z0208 were measured. The results are shown in Table 4. It can be seen that the moisture resistance is further improved by using the fatty acid ester as a blending method during the latex polymerization.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

The coated paper using the copolymer resin emulsion and the moisture-proofing composition of the present invention is superior in moistureproofness to the conventional coated papers using polymers.
Moreover, since a coated paper having a low coating amount may be repulped, it is very useful for moisture-proof coating.

Claims (4)

(57) [Claims] 1. A butadiene latex containing 0.1 to 1 part by weight of a reactive emulsifier , and a fatty acid ester compound obtained by reacting a fatty acid with an alcohol in a weight ratio of 100: 0.1. A copolymer resin emulsion, characterized in that it is contained in a ratio of 5. 2. The fatty acid is stearic acid.
The copolymer resin emulsion described. 3. An aqueous medium comprising 100 parts by weight of butadiene and an ethylenically unsaturated monomer copolymerizable therewith, 0.1 to 5 parts by weight of a fatty acid ester compound and 0.1 to 1 part by weight of a reactive emulsifier. A method for producing a copolymer resin emulsion, characterized in that emulsion polymerization is carried out therein. 4. A composition for moisture-proofing, which comprises the copolymer resin emulsion according to claim 1 or 2 as a main component.