JPH09194812A - Self-adhesive emulsion composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-adhesive emulsion composition having less tack of the coated surface, good adhesiveness between coated surfaces, and excellent antiaging property. SOLUTION: A monomer component contg. at least one of an alkyl ester of acrylic acid having a 1-8C alkyl group and/or an alkoxyethyl ester of acrylic acid having an 1-4C alkoxy group in an amount of not less than 70wt.%, is emulsion polymerized on the presence of a polymer dispersing composed of an alkali neutralized salt of a polymer, of which monomer is essentially a vinylunsaturated monomer in the form of a carboxylic acid or an acid anhydride. This composition comprises an acryl emulsion of a polymer obtd. by the emulsion polymerization and have a glass transition temperature of -50-0 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called self-adhesive emulsion composition which has less tack on coated surfaces and which can be adhered by superimposing and pressing the coated surfaces.

[0002]

2. Description of the Related Art An adhesive having self-adhesiveness is an adhesive that can adhere the coated surfaces to each other by superposing the coated surfaces and applying pressure with mechanical pressure or finger pressure. Natural rubber latex, styrene-butadiene rubber latex, synthetic rubber latex such as chloroprene rubber latex are known as those having such properties. In particular, natural rubber latex has less tack on the coated surfaces and is excellent in self-adhesion between the coated surfaces, and therefore, for example, a double-sided pressure-sensitive adhesive for sealing mail, a double-sided coating aqueous contact adhesive, etc. ,
It is used as a cold-seal adhesive used for confidentiality postcards and the like for privacy protection related to personal information.

However, natural rubber lax has a fundamental defect that its performance deteriorates over time due to aging of the resin, and modification with acrylics, blending of an ultraviolet absorber and the like have been attempted for improvement. However, no one having sufficiently satisfactory performance has been obtained.

On the other hand, acrylic resin emulsions are excellent in aging resistance and are used in various applications such as binders for paints, adhesives, and fibrous chemicals, but in terms of self-adhesiveness, they are natural rubber latex. It is inferior to the comparison. It is generally considered that the self-adhesiveness is caused by the entanglement of polymer chains at the contact interface when the coated surfaces of the adhesive are pressure-bonded, but in the acrylic resin emulsion, it is used during emulsion polymerization. It is considered that the emulsifier is present at the contact interface, which greatly hinders contact and entanglement of polymer chains. With respect to such an acrylic resin emulsion, it is possible to increase the self-adhesiveness by setting the glass transition temperature low, but when the glass transition temperature is lowered,
There is a problem in that the tack of the coated surface becomes too strong and blocking easily occurs. On the other hand, if the glass transition temperature is set high in order to reduce the tack on the coated surface, a practical level of self-adhesiveness cannot be obtained due to the inhibition of adhesion by the emulsifier.

[0005]

SUMMARY OF THE INVENTION The main object of the present invention is to:
It is an object of the present invention to provide a self-adhesive emulsion composition having less tack on the coated surfaces, good self-adhesiveness between the coated surfaces, and excellent aging resistance.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, in the presence of a specific polymer dispersant, a specific acrylic monomer, and Accordingly, in addition to the acrylic monomer, an acrylic emulsion obtained by emulsion-polymerizing a vinyl unsaturated monomer copolymerizable therewith and having a glass transition temperature of the polymer in the range of −50 to 0 ° C. , Less tack,
It has been found that it has good self-adhesiveness and excellent aging resistance, and has completed the present invention.

That is, according to the present invention, in the presence of a polymer dispersant comprising an alkali-neutralized salt of a polymer having a vinyl unsaturated monomer in the form of a carboxylic acid or an acid anhydride as an essential monomer component, a carbon number of 1 is used. Obtained by emulsion polymerization of a monomer component containing 70% by weight or more of at least one of acrylic acid alkyl ester having an alkyl group of 8 to 8 and acrylic acid alkoxyethyl ester having an alkoxy group of 1 to 4 carbon atoms. The present invention relates to a self-adhesive emulsion composition comprising an acrylic emulsion having a glass transition temperature of -50 to 0 ° C.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The self-adhesive emulsion composition of the present invention comprises, as a monomer component, an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and 1 carbon atom.
It is obtained by emulsion-polymerizing at least one of acrylic acid alkoxyethyl esters having an alkoxy group of 4 to 4 (both may be referred to as "acrylic monomers" hereinafter).

Examples of the alkyl acrylate whose alkyl group has 1 to 8 carbon atoms include methyl acrylate,
Ethyl acrylate, butyl acrylate, acrylic acid 2-
Ethylhexyl etc. can be mentioned. Further, examples of the acrylic acid alkoxyethyl ester having an alkoxy group having 1 to 4 carbon atoms include 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, and 2-butoxyethyl acrylate. In the present invention, one of the above-mentioned acrylic acid alkyl ester and acrylic acid alkoxyethyl ester may be used alone or two or more thereof may be used in combination.

In the above acrylic monomers, the tackiness of the coated surface tends to increase as the number of carbon atoms in the alkyl group increases, so methyl acrylate, ethyl acrylate,
Acrylic acid alkyl esters having an alkyl group having 1 to 4 carbon atoms such as butyl acrylate are preferred in that they have appropriate tack, and ethyl acrylate is particularly preferred because it has a good balance between low tackiness and self-adhesiveness. .

In the present invention, it is necessary to use the above-mentioned acrylic monomer as a monomer component in an amount of 70% by weight or more based on the total amount of the monomers. In addition to these acrylic monomers, copolymerization with the acrylic monomer is required. Possible vinyl unsaturated monomers can be used in the range of up to 30% by weight of the total amount of monomers. As such a vinyl-based unsaturated monomer, a non-functional monomer, a monomer having a hydrophilic functional group, or the like can be used depending on the purpose.

Among these vinyl-based unsaturated monomers, examples of non-functional monomers include homopolymers such as vinyl acetate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, styrene and acrylonitrile, which have a glass transition temperature of 30. It is preferable to use a monomer having a temperature of not less than 0 ° C., and by using these non-functional monomers, the tack of the polymer can be reduced.

Further, as the monomer having a hydrophilic functional group, vinyl unsaturated monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid and itaconic acid, 2-hydroxyethyl acrylate, 2-methacrylic acid Vinyl unsaturated monomers having hydroxyl groups such as hydroxyethyl, vinyl unsaturated monomers having amide groups such as acrylamide and methacrylamide, vinyl unsaturated monomers having N-methylol groups such as N-methylol acrylamide and N-methylol methacrylamide. Saturated monomer,
Vinyl-based unsaturated monomers having an amino group such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate, vinyl-based unsaturated monomers having a sulfonic acid group such as sodium vinyl sulfonate, sodium styrene sulfonate, and 2-acrylamido-2-propane sulfonic acid. Saturated monomers and the like can be exemplified, and by using these monomers having a hydrophilic functional group, the obtained emulsion can be further stabilized.

The vinyl unsaturated monomer copolymerizable with these acrylic monomers can be used in the range of 30% by weight or less based on the total amount of the monomers, and among these, monomers having a hydrophilic functional group. With respect to, since the self-adhesiveness of the obtained emulsion composition is apt to deteriorate when the amount used is too large,
It is preferably used within the range of less than 2% by weight, and more preferably within the range of 2% by weight or less.

Further in the present invention, the above-mentioned monomer component is
The glass transition temperature of the polymer obtained by emulsion polymerization is -5.
It is necessary to select it so as to be in the range of 0 to 0 ° C. By setting the glass transition temperature within this temperature range, it is possible to achieve both low tackiness and good self-adhesive strength. If the glass transition temperature of the obtained polymer is below -50 ° C, the tack of the coated surface becomes too strong, which is not preferable, while if the glass transition temperature exceeds 0 ° C, the self-adhesiveness is lowered, which is not preferable.

The glass transition temperature of the obtained polymer is
It can be determined from the glass transition temperature of the homopolymer formed by each monomer component by the following formula.

1 / Tg = W1 / Tg1 + W2 / Tg2 +
... + Wn / Tgn where Tg: glass transition temperature of polymer (absolute temperature) W1 to Wn: weight fraction of monomer components 1 to n Tg1 to Tgn: glass transition temperature of homopolymer of monomer components 1 to n (absolute temperature) Temperature) An example of the glass transition temperature of the homopolymer used in the calculation is as follows.

Methyl acrylate: + 8 ° C, ethyl acrylate: -19 ° C, butyl acrylate: -52 ° C, 2-ethylhexyl acrylate: -74 ° C, 2-methoxyethyl acrylate: -45 ° C, acrylic acid 2 -Ethoxyethyl: -50 ° C, methyl methacrylate: 120 ° C, styrene: 105 ° C, vinyl acetate: 29 ° C, acrylonitrile: 104 ° C, acrylic acid: 106 ° C, methacrylic acid:
185 ° C.

The emulsion composition of the present invention comprises a polymer dispersant comprising an alkali-neutralized salt of a polymer containing the above-mentioned monomer component as an essential monomer component of a vinyl unsaturated monomer in the form of a carboxylic acid or an acid anhydride. It can be obtained by emulsion polymerization in the presence of. The polymer dispersant is used as an emulsifier during emulsion polymerization, has a function of smoothly proceeding emulsion polymerization and keeping the obtained emulsion stable, and further has cohesive force itself. , Is believed to have the effect of enhancing self-adhesion at the contact interface between the coated surfaces of the resulting emulsion,
Adhesion inhibition at the contact interface such as conventionally used emulsifiers is small, and the resulting emulsion has high self-adhesiveness and is well balanced between low tackiness and self-adhesiveness.

Specific examples of the vinyl unsaturated monomer in the form of carboxylic acid or acid anhydride, which is an essential monomer component of the polymer used as the polymer dispersant, include acrylic acid, methacrylic acid, maleic acid, fumaric acid and croton. Examples thereof include acid, itaconic acid, maleic anhydride, itaconic anhydride and the like. These respective monomers can be used alone or in an appropriate mixture.

The polymer used as the polymer dispersant in the present invention is a polymer containing only the vinyl unsaturated monomer in the form of the above-mentioned carboxylic acid or acid anhydride as a monomer component, or other than the vinyl unsaturated monomer. In addition to this, it is a copolymer containing, as a monomer component, another vinyl unsaturated monomer copolymerizable with the monomer.

Examples of vinyl unsaturated monomers copolymerizable with vinyl unsaturated monomers in the form of carboxylic acid or acid anhydride include (meth) acrylic acid alkyl esters such as methyl methacrylate and ethyl acrylate, ( Hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, (meth) acrylamide derivatives such as (meth) acrylonitrile, acrylamide, sulfonic acid-based monomers such as sodium vinyl sulfonate, sodium styrene sulfonate, dibutyl maleate, Examples thereof include maleic acid esters such as dioctyl maleate, vinyl acetate, styrene and the like.

The polymer used as the polymer dispersant preferably has a number average molecular weight of about 400 to 10,000. When the molecular weight is out of this range, the stability during emulsion polymerization is poor and the stability of the resulting emulsion is high. It is not preferable because it is insufficient. Further, the polymer preferably has an acid value of 200 or more. In addition to the vinyl unsaturated monomer in the form of carboxylic acid or acid anhydride, the polymer has a vinyl type copolymerizable with it. In the case of a copolymer containing a saturated monomer as a monomer component, it is appropriate to select the type and amount of the monomer component so that the acid value is 200 or more.

Among the polymers having a vinyl unsaturated monomer in the form of a carboxylic acid or an acid anhydride as an essential monomer component, those which can be preferably used in the present invention include polyacrylic acid, polymethacrylic acid, ( (Meth) acrylic acid / (meth) acrylic acid alkyl ester copolymer, (meth) acrylic acid / styrene copolymer, (meth) acrylic acid / (meth) acrylic acid alkyl ester / styrene copolymer, styrene / maleic anhydride An acid copolymer etc. can be illustrated.

Among these polymers, polymethacrylic acid, methacrylic acid copolymer and the like are particularly preferable because they are excellent in self-adhesiveness.

The polymer containing the vinyl unsaturated monomer in the form of the carboxylic acid or acid anhydride as an essential monomer component is
For example, it can be obtained by polymerizing the above monomer using a radical polymerization initiator in water, a hydrophilic organic solvent, or a mixed liquid of water and the hydrophilic organic solvent. Examples of the hydrophilic organic solvent that can be used at this time include alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, ketones such as acetone and methyl ethyl ketone, ethylene glycol monomethyl ether,
Examples thereof include glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether. Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4
An azo-based polymerization initiator such as dimethylvaleronitrile), t
-Peroxide type polymerization initiators such as butyl hydroperoxide, benzoyl peroxide, lauroyl peroxide and the like can be used. The amount of radical polymerization initiator used is 0.2 to 10 with respect to the total amount of polymerization monomers.
It may be about wt%, preferably about 0.5 to 5 wt%. The reaction temperature at the time of polymerization is usually about 50 to 120 ° C., and the reaction time is usually about 1 to 16 hours, preferably about 2 to 8 hours. Since the organic solvent used acts as a chain transfer agent when an acrylic emulsion is obtained by emulsion polymerization, it is preferable to evaporate it after the polymerization by raising the temperature and, if necessary, reducing the pressure.

The carboxyl group contained in the polymer containing a vinyl unsaturated monomer in the form of carboxylic acid or acid anhydride as an essential monomer component is neutralized in part or in whole,
It is used as a polymer dispersant in the form of an alkali neutralized salt.
Examples of the alkaline compound used for the neutralization include amine compounds such as monoethylamine, diethylamine, triethylamine, monoethanolamine, dimethylaminoethanol and morpholine, and inorganic alkaline compounds such as ammonia, sodium hydroxide and potassium hydroxide. The degree of neutralization may be in the range of about 30 to 100%, and if the degree of neutralization is below this range, hydrophilicity is insufficient and a stable emulsion is difficult to obtain, which is not preferable.

Specific examples of the polymer dispersant that can be used in the present invention include, for example, Toughtic AD (trademark: manufactured by Toyobo Co., Ltd.) and SN-4 (trademark: manufactured by Sumitomo Dow Co., Ltd.). You can use what has been done. Also, Japanese Examined Sho 46
The oligomer having an alkyl sulfide group at the end described in JP-A-10786 can also be used as a polymer dispersant.

The amount of the polymeric dispersant used may be about 0.1 to 5.0% by weight based on the total amount of the monomers.
Preferably, it should be about 0.2 to 2.5% by weight. If the amount of the polymer dispersant used is too small, a stable emulsion cannot be obtained, and if it is too large, the self-adhesiveness is deteriorated, which is not preferable.

In the present invention, in the emulsion polymerization, a general emulsifier used in ordinary emulsion polymerization can be used in combination with the above-mentioned polymer dispersant. However, if the amount of these emulsifiers used is too large, when the obtained emulsion is used as a self-adhesive adhesive, the emulsifier migrates to the coating surface and hinders the self-adhesiveness, which is not preferable. . Further, when an emulsifier having an ethylene oxide group, a propylene oxide group or the like in the molecular structure is used, a low molecular weight polymer component is easily generated due to a chain transfer reaction during emulsion polymerization, and such a low molecular weight polymer is formed. When done,
There is a problem that this migrates to the coated surface and hinders self-adhesiveness.

Therefore, it is appropriate that the amount of the emulsifier other than the above-mentioned polymer dispersant is within the same range as the amount of the polymer dispersant used.

Examples of such emulsifiers include the following.

Anionic emulsifier: potassium oleate,
Sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium alkanesulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl allyl ether sulfate, polyoxyethylene alkyl ether phosphate , Polyoxyethylene alkyl allyl ether phosphate, etc.

Nonionic emulsifier: polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oxypropylene block polymer, polyethylene glycol fatty acid ester, polyoxyethylene sorbitan fatty acid ester and the like.

Cationic emulsifiers: stearylamine hydrochloride, lauryltrimethylammonium chloride, trimethyloctadecylammonium chloride and the like.

Zwitterionic emulsifiers: lauryl betaine, lauryl dimethylamine oxide, etc.

Among these emulsifiers, an emulsifier having a polymerizable double bond in the molecular structure, which is commercially available as a so-called reactive emulsifier, binds with the polymer particles and suppresses the migration of the emulsifier. It is particularly preferable for the purpose of auxiliary use in combination with the polymer dispersant, since it does not lower the adhesiveness. As an example of such a reactive emulsifier, ADEKA REASOAP SE-10N (trademark: Asahi Denka Kogyo Co., Ltd.)
), Latemur S-180 (trademark: manufactured by Kao Corporation), Eleminol JS-2 (trademark: manufactured by Sanyo Chemical Industry Co., Ltd.),
Aqualon HS-10 (Trademark: Daiichi Kogyo Seiyaku Co., Ltd.)
And manufactured by Antox MS-60 (trademark: manufactured by Nippon Emulsifier Co., Ltd.).

Emulsion polymerization for producing the acrylic emulsion of the present invention may be carried out by a conventional method. That is, in the presence of the polymer dispersant and, if necessary, other emulsifiers, the monomer and the polymerization initiator are supplied all at once at a predetermined temperature in an aqueous medium with stirring, or by continuous supply. Done. The monomer can be supplied as it is, or can be supplied as a monomer emulsion with water and an emulsifier.

The monomer concentration is usually about 30 to 70% by weight, preferably 35 to 65% by weight, based on the total charged amount.
It should be about the degree.

As the polymerization initiator, a commonly used radical polymerization initiator, for example, ammonium persulfate,
Persulfates such as potassium persulfate, azo polymerization initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), t-butyl hydroperoxide Further, a peroxide-based initiator such as benzoyl peroxide and lauroyl peroxide can be used. The amount of the radical polymerization initiator used is 0.05 to 5% by weight based on the total amount of the polymerization monomers.
The amount may be about 0.2 to 3% by weight.

In order to carry out redox polymerization, a reducing agent may be used in combination with the radical polymerization initiator. Examples of the reducing agent include sodium hyposulfite, sodium thiosulfate, formaldehyde sodium sulfoxylate and the like. The reducing agent is usually used in a weight ratio of about 1/10 to 1/1 with respect to the polymerization initiator.

The reaction temperature during emulsion polymerization is usually 20 to 90 ° C.
However, if the polymerization temperature is too high, low molecular weight components are likely to be generated during the polymerization reaction.
It is preferably within the range of about. Reaction time is usually 1
It may be about 16 hours, preferably about 2 to 8 hours.

The self-adhesive emulsion composition of the present invention has less tack on the coated surfaces, excellent self-adhesiveness between the coated surfaces, and good aging resistance. For example, double-sided used for sealing mail. It can be effectively used as a pressure-sensitive adhesive, a double-sided coating water-based contact adhesive, a cold seal adhesive, and the like.

When the emulsion composition of the present invention is used as a double-sided pressure-sensitive adhesive, a double-sided coating type water-based contact adhesive, etc., the composition contains an organic solvent, a plasticizer, a tackifier, and a thickener. Etc. can be blended.

Examples of the plasticizer that can be used include aromatic dibasic acid dialkyl esters such as dibutyl phthalate and dioctyl phthalate, and aliphatic dibasic acid dialkyl esters such as dimethyl succinate and diisobutyl adipate. As the organic solvent, for example, toluene, aromatic solvents such as xylene, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, glycol ether solvents such as propylene glycol monomethyl ether, cyclohexanone, ketone such as methyl isobutyl ketone. Examples of the solvent include ester solvents such as butyl acetate and isobutyl acetate. These plasticizers and organic solvents are used auxiliary to improve the self-adhesiveness by softening the resin, and the compounding amount is usually 1 with respect to 100 parts by weight of the nonvolatile content in the emulsion composition. It is used in the range of about 50 parts by weight.

Examples of the tackifier include rosin derivatives such as polymerized rosin and hydrogenated rosin, terpene resins, terpene modified products such as terpene phenol resins, coumarone indene resins, aliphatic hydrocarbon resins and aromatic petroleum resins. A phenolic resin, a styrene resin, a xylene resin or the like can be used. The tackifier can be combined with the resin component to improve the adhesion and self-adhesiveness to the base material as an adhesive, and the compounding amount is usually 100 parts by weight of the nonvolatile content in the emulsion composition. On the other hand, the range may be about 5 to 100 parts by weight.

The cold-seal adhesive is required to have a property that it can be adhered by press-bonding the coated surfaces to each other under a high pressure, and once peeled off, it will not be re-adhered in a normal state. Fillers such as corn starch, calcium carbonate, silica, kaolin, clay, talc, titanium oxide, zinc oxide, and shirasu balloon are blended to adjust the adhesive properties. The average particle diameter of the filler is preferably about 1 to 20 μm, and the compounding amount is usually
The amount of the filler may be in the range of about 5 to 100 parts by weight with respect to 100 parts by weight of the nonvolatile content in the emulsion composition.

[0048]

EXAMPLES The present invention will be described in more detail below with reference to Reference Examples and Examples.

Reference Example 1 700 g of water was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, and the temperature was raised to 95 ° C.
Next, while stirring, 9 g of potassium persulfate was added, and then 300 g of methacrylic acid was continuously added dropwise into the reaction vessel in the dropping funnel over 3 hours, and the aging reaction was further carried out at 95 ° C.
Time went. As a result, the nonvolatile content was 30% and the viscosity was 3500.
A transparent viscous liquid of polymethacrylic acid of 0 mPa · s was obtained. The number average molecular weight of this polymethacrylic acid was 650 as measured by GPC, and the acid value was 652 as a calculated value.

Reference Example 2 700 g of water was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, and the temperature was raised to 95 ° C. Then, while stirring, add 9 g of potassium persulfate,
A mixture of 210 g of methacrylic acid and 90 g of butyl acrylate was continuously added dropwise into the reaction vessel over 3 hours with a dropping funnel, and further an aging reaction was performed at 95 ° C for 1 hour. as a result,
A cloudy dispersion having a nonvolatile content of 30% and a viscosity of 10 mPa · s was obtained. The number average molecular weight of the obtained polymer was 4200 as measured by GPC, and the acid value was 456 as calculated.

Reference Example 3 500 g of isopropyl alcohol was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel,
The temperature was raised to 80 ° C. Next, with stirring, 2.5 g of 2,2′-azobisisobutyronitrile was added, and then a mixture of 150 g of acrylic acid, 350 g of acrylic acid ethyl ester and 30 g of n-dodecyl mercaptan was placed in a reaction vessel with a dropping funnel. Was continuously added dropwise over 3 hours, and the aging reaction was carried out for 2 hours at the same temperature. As a result, the nonvolatile content of 50
%, A resin solution having a viscosity of 280 mPa · s was obtained. Then, after distilling off isopropyl alcohol from this resin solution by distillation, 140 g of 25% ammonia water and an appropriate amount of water were added to give a nonvolatile content of 50% and a viscosity of 1100 mPas.
A transparent viscous resin aqueous solution of s was obtained. The number average molecular weight of the obtained polymer was 2800 as measured by GPC, and the acid value was 234 as calculated.

Example 1 A reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel was charged with 150 g of water, 12.5 g of the polymethacrylic acid aqueous solution of Reference Example 1 and 2.5 g of 25% aqueous ammonia, The temperature was raised to 60 ° C., and 12 g of a 10% aqueous solution of ammonium persulfate was added with stirring. On the other hand, a monomer emulsion consisting of 500 g of ethyl acrylate, 6.5 g of an emulsifier (manufactured by Sanyo Kasei Co., Ltd., Eleminol JS-2) and 225 g of water was prepared separately, and this was placed in the reaction vessel with a dropping funnel for 4 hours. It dripped continuously over. During this period, the polymerization temperature was maintained at 60 ° C., and after completion of the dropwise addition, an aging reaction was performed at 60 ° C. for 2 hours. After the reaction, the reaction solution was allowed to cool to 30 ° C. and 1.5 g of 25% aqueous ammonia was added to obtain an aqueous emulsion having a nonvolatile content of 55% by weight, a viscosity of 100 mPa · s and a pH of 8.6. The calculated glass transition temperature (Tg) of the polymer in the obtained emulsion was -19 ° C. This is designated as Product 1 of the present invention.

Example 2 150 g of water, 25.0 g of the methacrylic acid copolymer dispersion of Reference Example 2 and 5.0 g of 25% aqueous ammonia were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel. After charging, the temperature was raised to 60 ° C., and 12 g of a 10% aqueous solution of ammonium persulfate was added with stirring. On the other hand, ethyl acrylate 490 g, 80% acrylic acid 12.5 g, 25
% Ammonia water 9.5 g, emulsifier (Daiichi Kogyo Seiyaku Co., Ltd.)
(Manufactured by Aqualon HS-10) (2.5 g) and water (225 g) were separately prepared, and the monomer emulsion was continuously dropped into the reaction vessel over 4 hours with a dropping funnel. During this period, the polymerization temperature was kept at 60 ° C. and 60
The aging reaction was carried out at 0 ° C for 2 hours. After the reaction, the reaction solution is at 30 ℃
The mixture is allowed to cool, and 1.5 g of 25% aqueous ammonia is added to it to give a nonvolatile content of 55% by weight, a viscosity of 160 mPa · s, and a pH of 8.6.
An aqueous emulsion of The glass transition temperature (Tg) of the polymer in the obtained emulsion was -17 ° C as a calculated value.
Met. This is designated as Product 2 of the present invention.

Example 3 400 g of water and 25 g of the acrylic acid copolymer aqueous solution of Reference Example 3 were charged into a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, and the temperature was raised to 60 ° C. Next, with stirring, 12 g of a 10% aqueous solution of ammonium persulfate
Then, 500 g of ethyl acrylate was continuously dropped into the above reaction vessel over 4 hours with a dropping funnel. During this period, the polymerization temperature was kept at 60, and the aging reaction was carried out at 60 ° C. for 2 hours after the dropping was completed. After the reaction, the reaction solution was left to cool to 30 ° C,
Non-volatile content 55 by adding 1.5 g of 25% aqueous ammonia
An aqueous emulsion having a weight percentage of 100 mPa · s and a pH of 8.7 was obtained. The calculated glass transition temperature (Tg) of the polymer in the obtained emulsion was -19 ° C.
This is referred to as product 3 of the present invention.

Examples 4 to 6 An aqueous emulsion was obtained in the same manner as in Example 1 except that the monomers shown in Table 1 were used instead of ethyl acrylate in Example 1. Table 1 shows the nonvolatile content, viscosity, pH, and glass transition temperature (Tg) (calculated value) of the obtained emulsion. These emulsions are referred to as Products 4 to 6 of the present invention.

[0056]

[Table 1]

Comparative Example 1 A reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel was charged with 150. g, and 10.0 g of polyoxyethylene nonylphenyl ether (manufactured by Sanyo Kasei Co., Ltd., Nonipol 200), heated to 60 ° C., and stirred, while stirring, 12 g of a 10% aqueous solution of ammonium persulfate.
Was added. On the other hand, a monomer emulsion consisting of 490 g of ethyl acrylate, 12.5 g of 80% acrylic acid, 10.0 g of polyoxyethylene nonylphenyl ether sulfate ammonium salt (Eleminol ES-70 manufactured by Sanyo Chemical Industry Co., Ltd.), and 225 g of water. Was separately prepared, and this was continuously added dropwise to the above reaction vessel for 4 hours with a dropping funnel. During this period, the polymerization temperature was maintained at 60 ° C., and after completion of the dropwise addition, an aging reaction was performed at 60 ° C. for 2 hours. After the reaction, the reaction solution was allowed to cool to 30 ° C., and 25% ammonimore water 9.5 g
Non-volatile content 55 wt%, viscosity 1,600 mPa
An aqueous emulsion of s, pH 8.4 was obtained. The glass transition temperature (Tg) of the polymer in the obtained emulsion is
The calculated value was -17 ° C. This is designated as Comparative Product 1.

Comparative Production Examples 2 to 4 An aqueous emulsion was obtained in the same manner as in Example 1, except that the monomers shown in Table 2 were used instead of ethyl acrylate in Example 1. Table 2 shows the nonvolatile content, viscosity, pH, and glass transition temperature (Tg) (calculated value) of the obtained emulsion. Compare these emulsions with Comparative Product 2
To 4.

[0059]

[Table 2]

Performance Evaluation Test 1 Each of the products 1 to 6 of the present invention and the comparative products 1 to 4 was coated on a high quality paper using a bar coater so that the coating amount was 8 g / m ^2, and a hot air circulation dryer was used. And dried at 105 ° C. for 2 minutes. A hand roll having a weight of 2 kg was reciprocated once at a speed of 300 mm per minute and pressure-bonded from the superposed coated surfaces to obtain a measurement sample having a width of 25 mm. The peel strength of these samples was measured by a T-shaped peel test at a tensile speed of 300 mm / min using a tensile tester.

On the other hand, the tack state of the coated surface of the prepared sample was judged by touching with a finger. ◎ Use something that is not sticky to the touch.
The one with a large stickiness was marked with X, and the one with a medium stickiness was marked with ◯. The results are shown in Table 3 below.

[0062]

[Table 3]

Performance Evaluation Test 2 For each of the products 1 to 6 of the present invention, the comparative products 1 to 4 and the natural rubber latex (comparative product 5), flour starch (average particle size 30 μm) was added to 100 parts by weight of the nonvolatile content. 50 parts by weight and 3 parts of silica powder (average particle size 1.5 μm), respectively.
0 parts by weight were blended to obtain an adhesive composition for cold seal.

This adhesive composition was applied to a high-quality paper in an amount of 8 g /
m ² to be applied using a bar coater and dried for 2 minutes at 105 ° C. using a hot air circulation dryer, and then the applied surfaces are pressure-bonded with each other at a linear pressure of 100 kgf / cm to give a width of 25 mm.
A sample for measurement was obtained. The peel strength of these samples was measured by T-shaped peeling at a tensile speed of 300 mm / min with a tensile tester. For each coated sample, 1
Irradiation was performed from a position of 20 cm with four 5 watt ultraviolet lamps, and the irradiation time until adhesion was stopped even when pressure was applied was measured to evaluate the aging resistance.

On the other hand, the coated surface and the non-coated surface of the coated sample prepared in the same manner were overlapped and the coated sample was placed in a constant temperature dryer at 50 ° C. for 1 hour.
After leaving it under a pressure of 00 gf / m ² for 16 hours, the pressure is released,
After being left for 3 hours in the standard state, peeling by hand, with low resistance and easy peeling at the time of peeling ◎, with high resistance and difficult to peel off or paper quality to destroy ×, middle grade is ○ The blocking resistance was evaluated as.

The above results are shown in Table 4 below.

[0067]

[Table 4]

Claims (4)

[Claims] 1. A carbon dispersant having 1 carbon atom in the presence of a polymer dispersant comprising an alkali-neutralized salt of a polymer containing a vinyl unsaturated monomer in the form of a carboxylic acid or an acid anhydride as an essential monomer component.
70% by weight of at least one of acrylic acid alkyl ester having 1 to 8 alkyl group and acrylic acid alkoxyethyl ester having 1 to 4 carbon alkoxy group
The glass transition temperature of the polymer obtained by emulsion polymerization of the above-mentioned monomer components, obtained by the emulsion polymerization is -50 to 0.
A self-adhesive emulsion composition comprising an acrylic emulsion having a temperature of 0 ° C. 2. A polymer dispersant, which is an alkali-neutralized salt of a polymer containing only a vinyl unsaturated monomer in the form of a carboxylic acid or an acid anhydride as a monomer component, and the vinyl unsaturated monomer and other copolymers. It is at least one kind of alkali-neutralized salt of a copolymer containing a possible vinyl unsaturated monomer as a monomer component, and the acid value of the polymer or the copolymer is 20.
The self-adhesive emulsion composition according to claim 1, which is 0 or more and has a number average molecular weight of 400 to 10,000. 3. The polymer dispersant is polyacrylic acid, polymethacrylic acid, (meth) acrylic acid / (meth) acrylic acid alkyl ester copolymer, (meth) acrylic acid / styrene copolymer, (meth). The self-adhesive emulsion composition according to claim 2, wherein the self-adhesive emulsion composition is at least one of alkali-neutralizing salts of acrylic acid / (meth) acrylic acid alkyl ester / styrene copolymer and styrene / maleic anhydride copolymer. 4. The polymer dispersant according to claim 3, which is at least one of an alkali neutralization salt of polymethacrylic acid and an alkali neutralization salt of a copolymer of methacrylic acid and a vinyl unsaturated monomer. Self-adhesive emulsion composition.