JPH10219227A - Tack-imparting resin emulsion and aqueous tacky agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition useful for an aqueous tacky agent for label, etc., excellent in bonding strength, color tone and weather resistance by using an emulsion of a colorless rosin and/or a colorless rosin ester. SOLUTION: This emulsion is obtained by emulsifying a colorless rosin and/or a colorless rosin ester having <=2 Gardner color scale in the presence of an emulsifying agent. Preferably the rosin is obtained by dehydrogenating a purified rosin or a purified and disproportionated rosin or hydrogenated rosin and the ester is an ester obtained by using the rosin obtained by the above-mentioned treatment and carrying out dehydrogenation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tackifier resin emulsion and an aqueous pressure-sensitive adhesive composition. For more information,
The tackifier resin emulsion of the present invention can be used as an aqueous pressure-sensitive adhesive composition which is blended with an acrylic polymer emulsion or rubber-based latex and used for various uses such as labels, sheets, and tapes.

[0002]

2. Description of the Related Art Water-based pressure-sensitive adhesives have various advantages over organic solvent-based pressure-sensitive adhesives, such as being free from air pollution, excellent in safety and health, and suitable for resource saving. Agents tend to be converted to aqueous adhesives.
Thus, as the application of the water-based pressure-sensitive adhesive has expanded, the performance required of the water-based pressure-sensitive adhesive has also become higher. As such required performance, color tone and weather resistance have also been emphasized in addition to adhesive strength to polyolefin substrates such as polypropylene and polyethylene.

In general, the adhesion to a polyolefin substrate is improved by incorporating a tackifying resin emulsion such as rosin or rosin ester into an aqueous pressure-sensitive adhesive having an acrylic polymer emulsion or a rubber-based latex as a base resin. ing.

However, since rosin and rosin ester are generally colored (generally about 8 in Gardner color), there is a disadvantage that the color tone of the pressure-sensitive adhesive composition decreases as the added amount increases. In addition, rosin and rosin ester also have the disadvantage that they are easily oxidized due to the presence of a double bond in the rosin skeleton, and are inferior in weather resistance.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a tackifying resin emulsion which imparts excellent adhesive strength and is excellent in color tone and weather resistance, and an aqueous resin obtained by blending the tackifying resin emulsion. It is intended to provide a pressure-sensitive adhesive composition.

[0006]

Means for Solving the Problems In view of the above-mentioned problems of a water-based pressure-sensitive adhesive composition obtained by blending a tackifier resin emulsion with an existing acrylic polymer emulsion or rubber-based latex, the present inventors have made intensive studies. As a result of repeated studies, they have found that the above problem can be solved by using the following colorless rosin and / or colorless rosin ester emulsion as a tackifier resin emulsion, and have completed the present invention.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The tackifier resin emulsion of the present invention comprises a resin emulsion obtained by emulsifying a colorless rosin and / or a colorless rosin ester having a Gardner color of 2 or less in the presence of an emulsifier. . The color of the colorless rosin and / or the colorless rosin ester is
Preferably it is Gardner color 1 or less. When the color tone exceeds Gardner Color 2, the color tone and weather resistance of the pressure-sensitive adhesive composition deteriorate.

The method for producing the colorless rosin and / or the colorless rosin ester used as the tackifying resin of the present invention is not particularly limited as long as the color tone is Gardner Color 2 or less. Colorless rosin obtained by subjecting rosin to dehydrogenation or hydrogenation, colorless rosin ester subjected to dehydrogenation during or after esterification of rosin subjected to specific treatment, specific treatment A colorless rosin ester which has been subjected to a hydrogenation treatment after the esterification reaction of the rosin subjected to the above can be used.

The rosin subjected to the specific treatment includes a purified rosin, a purified and disproportionated rosin, a purified and hydrogenated rosin (hereinafter referred to as purified rosins). Is raised. Among the purified rosins, a rosin subjected to a purification treatment and a disproportionation treatment, and a rosin subjected to a purification treatment and a hydrogenation treatment are preferable. The order of the purification treatment, the disproportionation treatment, the purification treatment, and the hydrogenation treatment is not particularly limited, but it is preferable to perform the purification treatment later. The rosin includes raw rosins such as gum rosin, wood rosin, and tall oil rosin.

[0010] Here, the purification treatment means a high molecular weight substance which is considered to have arisen from peroxide contained in the raw material rosin,
And removing unsaponifiable substances originally contained in the raw material rosin. More specifically, operations such as distillation, recrystallization, and extraction may be performed, and purification by distillation is preferable industrially. In the case of distillation, the temperature is usually 200 to 30.
The temperature is appropriately selected from the range of 0 ° C. and the pressure of 1 to 10 mmHg in consideration of the distillation time. In the case of recrystallization, for example, the raw material rosin or the disproportionated or hydrogenated rosin is dissolved in a good solvent, and then the solvent is distilled off to form a concentrated solution, and a poor solvent is added to this solution. It is done by doing. Good solvents include ketones such as benzene, toluene, xylene, chloroform, lower alcohol, and acetone;
Examples of acetates such as ethyl acetate include n-hexane, n-heptane, cyclohexane, and the like as poor solvents.
Isooctane and the like. Furthermore, in the case of extraction, the raw material rosin or the disproportionated or hydrogenated rosin is converted into an aqueous alkali solution using alkaline water,
The extraction is performed by extracting an insoluble unsaponifiable substance with an organic solvent and then neutralizing the aqueous layer.

The disproportionation treatment means that a raw rosin or a purified rosin is heated and reacted in the presence of a disproportionation catalyst. As the disproportionation catalyst, palladium-carbon,
Supported catalysts such as rhodium-carbon, platinum-carbon,
Various known materials such as metal powders such as nickel and platinum, and iodides such as iodine and iron iodide can be exemplified. The amount of the catalyst to be used is generally about 0.01 to 5% by weight, preferably 0.01 to 1% by weight, based on rosin, and the reaction temperature is 100 to 100%.
About 300 ° C, preferably lower limit 150 ° C, upper limit 290 ° C
It is. Further, the hydrogenation treatment means that the same treatment as the disproportionation treatment is performed under hydrogen pressure, and the hydrogen pressure is usually from normal pressure to about 200 kg / cm ^{2 in a} sealed container, preferably the lower limit is 50 kg / cm 2. Perform under about ² conditions.

The colorless rosin used as the tackifier resin in the present invention can be obtained by subjecting the purified rosins to a dehydrogenation treatment or by subjecting the purified rosins to a hydrogenation treatment. The dehydrogenation treatment is not particularly limited, and ordinary conditions can be adopted. For example, purified rosins are subjected to a hydrogen initial pressure of 10 kg / in a closed vessel in the presence of a dehydrogenation catalyst.
less than cm ^2, and preferably less than 5 kg / cm ^2, reaction temperature 100 to 300 ° C., preferably about lower 200 ° C., in a range between the upper limit 280 ° C.. Hydrogen is substantially unnecessary because it is a dehydrogenation reaction. However, in order to use the generated hydrogen for peroxide reduction, the initial hydrogen pressure is set to less than 10 kg / cm ^2. The pressure may be adjusted by pressure or slightly supplying hydrogen from outside. As the dehydrogenation catalyst, various known catalysts can be used without particular limitation, but preferably, palladium-based, rhodium-based,
Platinum-based catalysts can be exemplified, and are usually used by being supported on a carrier such as silica or carbon. The amount of the catalyst used is usually about 0.01 to 5% by weight, preferably 0.05% by weight at the lower limit and 3% by weight at the upper limit, based on the purified rosin. Note that the hydrogenation treatment refers to performing the same treatment as the disproportionation treatment under hydrogen pressure. Usually, the hydrogenation treatment is performed under a hydrogen pressure of 50% in a sealed container.
This is performed under the condition of about 200 kg / cm ² .

The colorless rosin used as the tackifier resin in the present invention includes the purified rosin and α, β-unsaturated monocarboxylic acid and / or α, β-unsaturated monocarboxylic acid.
A rosin that has been subjected to a hydrogenation treatment can be used for the addition reaction product obtained by subjecting a β-unsaturated dicarboxylic acid to a Diels-Alder reaction.

The α, β-unsaturated monocarboxylic acid includes acrylic acid, methacrylic acid, crotonic acid and the like, and the α, β-unsaturated dicarboxylic acid includes maleic acid, maleic anhydride, fumaric acid and the like. can give. The conditions for the addition reaction are a reaction temperature of about 180 to 240 ° C. and a reaction time of about 1 to 9 hours. The addition reaction is preferably carried out in the absence of oxygen in order to prevent coloring of the reaction product, and is usually carried out in a stream of an inert gas such as carbon dioxide gas or nitrogen gas. Α, β-unsaturated carboxylic acid to purified rosin (total amount of the carboxylic acid)
The reaction ratio may be appropriately adjusted, but is usually about 2 to 80 mol%, preferably 5 mol% at a lower limit and 77 mol% at an upper limit, based on purified rosin. The purification conditions and the hydrogenation treatment may be the same as described above.

The colorless rosin ester used as the tackifier resin in the present invention may be subjected to a dehydrogenation treatment during or after the esterification reaction of the purified rosins,
It is obtained by subjecting the purified rosins to a hydrogenation treatment after the esterification reaction. In the esterification reaction, ordinary rosin ester conditions for causing an esterification reaction between a rosin and a polyhydric alcohol can be employed as they are. For example, the purification is carried out by heating the purified rosin and the polyhydric alcohol to about 150 to 300 ° C. under an atmospheric pressure under an inert gas stream to remove water produced by the reaction outside the system. The charging ratio of the purified rosin and the polyhydric alcohol is not particularly limited, but usually, an amount of a polyhydric alcohol having a hydroxyl group equivalent to about 1.1 to 1.5 times the carboxyl group equivalent of the purified rosin is used. Good to use.

Examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and neopentyl glycol; trihydric alcohols such as glycerin, trimethylolethane, and trimethylolpropane; and tetrahydric alcohols such as pentaerythritol and diglycerin. Hydric alcohol; hexahydric alcohol such as dipentaerythritol. In addition,
In the reaction, an esterification catalyst is not necessarily required, but in order to shorten the reaction time, for example, an acid catalyst such as acetic acid and paratoluenesulfonic acid, an alkali metal hydroxide such as lithium hydroxide, and calcium hydroxide. Alkaline earth metal hydroxides and metal oxides such as calcium oxide and magnesium oxide can also be used.

When the dehydrogenation treatment is performed after the esterification reaction, the dehydrogenation may be performed under the same conditions as described above. When the dehydrogenation treatment is performed during the esterification reaction, purified rosins and polyhydric alcohols are charged in a predetermined amount under a nitrogen gas stream, and the reaction temperature is usually 150 to 150 ° C. in the presence of the dehydrogenation catalyst under atmospheric pressure. The reaction is performed by heating to about 300 ° C. to remove the reaction water outside the system. In the hydrogenation treatment after the esterification reaction, hydrogenation may be performed under the same conditions as described above.

The colorless rosin ester used as a tackifying resin in the present invention is obtained by reacting the purified rosin with an α, β-unsaturated monocarboxylic acid and / or an α, β-unsaturated dicarboxylic acid. It is also possible to use a rosin ester which has been subjected to an esterification reaction between the addition reaction product and a polyhydric alcohol and then subjected to a hydrogenation treatment.
The conditions for the esterification reaction and the hydrogenation treatment can be the same as those described above.

The colorless rosin and / or the colorless rosin ester thus obtained can be further added with an organic phosphorus compound to further improve the color tone stability.
Examples of the organic phosphorus compound include triphenyl phosphite, tricresyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite,
4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, cyclic neopentanetetraylbis (octadecylphosphite), tris (nonylphenyl) phosphite,
Tris (dinonylphenyl) phosphite, 9,10-
Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9
-Oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-
Oxa-10-phosphaphenanthrene and the like can be exemplified. The amount of the organic phosphorus compound used is 1.0% by weight or less, preferably 0.5% by weight or less based on the colorless rosin and / or the colorless rosin ester.

Emulsifiers used for emulsifying the colorless rosin and / or the colorless rosin ester include α-olefin sulfonates, alkyl sulfates, alkyl phenyl sulfates, polyoxyethylene alkyl phenyl ether sulfates and polyoxyethylene aralkyl phenyl ethers. Examples thereof include anionic emulsifiers such as a half ester salt of sulfosuccinic acid and rosin soap, and nonionic emulsifiers such as polyoxyethylene alkylphenyl ether. The amount of the emulsifier is not particularly limited, but is usually a colorless rosin and / or a colorless rosin ester 10
The amount is about 1 to 10 parts by weight, preferably 1 part by weight and 5 parts by weight, based on 0 parts by weight in terms of solids. If the amount exceeds 10 parts by weight, the water resistance of the water-based pressure-sensitive adhesive composition tends to decrease. If the amount is less than 1 part by weight, the stability of the resin emulsion during emulsification tends to deteriorate.

As a method of emulsifying a colorless rosin and / or a colorless rosin ester, for example, after dissolving a colorless rosin and / or a colorless rosin ester in a solvent such as benzene or toluene, the emulsifier and soft water are added;
A method in which the solvent is removed under reduced pressure after emulsification using a high-pressure emulsifier, a small amount of benzene so that the softening point of the colorless rosin and / or the colorless rosin ester is about 90 ° C. or less,
A method such as mixing a solvent such as toluene, kneading an emulsifier, gradually adding hot water and gradually phase-inverting to obtain an emulsion, and then removing the solvent under reduced pressure or using the solvent as it is, or an autoclave. In this method, the temperature is raised to above the softening point of the colorless rosin and / or colorless rosin ester, the emulsifier is kneaded, hot water is gradually added, and the emulsion is emulsified by phase inversion. Either method can be adopted in the invention.

The water-based pressure-sensitive adhesive composition of the present invention is obtained by blending the above-mentioned tackifying resin emulsion with an emulsion of an acrylic polymer or a rubber-based latex.

As the acrylic polymer emulsion,
Emulsions generally used for various acrylic pressure-sensitive adhesives can be used. The acrylic polymer emulsion is usually obtained by emulsion polymerization of an acrylic ester and / or a methacrylic ester. As the emulsion polymerization method, various methods such as a batch charge polymerization method, a monomer sequential addition polymerization method, an emulsion monomer sequential addition polymerization method, and a seed polymerization method can be employed.

The acrylate and methacrylate (hereinafter referred to as (meth) acrylate) monomers used are methyl (meth) acrylate, ethyl (meth) acrylate and butyl (meth) acrylate. Esters, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and the like. One of these may be used alone, or two or more may be mixed. Used. Further, in order to impart stability to the obtained emulsion, a part of the (meth) acrylic acid ester can be used in a small amount instead of (meth) acrylic acid. Further, if desired, a copolymerizable monomer such as vinyl acetate, styrene, or the like can be used in combination without impairing the adhesive properties of the (meth) acrylate polymer. The glass transition temperature of these (meth) acrylate-based polymers is generally about -70 to 0 ° C, preferably -60 to -10 ° C. If the temperature exceeds 0 ° C., the tack is undesirably reduced. Further, as an emulsifier used for the acrylic polymer emulsion, an anionic emulsifier, a partially saponified polyvinyl alcohol, or the like can be used, and its amount is usually 0.1 to 5 parts by weight based on 100 parts by weight of the acrylic polymer emulsion. It is about.

The amount of the tackifier resin emulsion of the present invention used with respect to the acrylic polymer emulsion is 2 to 2 parts by weight of the tackifier resin emulsion per 100 parts by weight (solid content) of the acrylic polymer emulsion.
It is preferable to mix and use it in the range of about 40 parts by weight (solid content conversion amount). In particular, the lower limit is preferably 5 parts by weight and the upper limit is preferably 20 parts by weight. If the amount of the tackifying resin emulsion is less than 2 parts by weight, it is difficult to impart sufficient adhesive strength. If the amount exceeds 40 parts by weight, not only the adhesive strength is reduced but also the adhesive becomes hard and the tackiness becomes high. Is also undesirably reduced.

As the rubber latex, styrene / butadiene copolymer latex (hereinafter, referred to as SBR latex), natural rubber latex (hereinafter, referred to as NR latex) and the like can be used. SBR latex refers to SBR latex and / or carboxy-modified S
BR latex, which is usually commercially available for adhesives can be used. In particular, in consideration of rubber elasticity, low-temperature physical properties, and the like, the bonding ratio of styrene / butadiene is preferably about 25/75 to 45/55 by weight. The gel fraction (toluene-insoluble matter weight%) is 35 to 65%.
Are preferred. Further, as the NR latex, either a depolymerized one or a non-depolymerized one can be used. One type of rubber latex such as SBR latex or NR latex may be used, or two or more types may be used by mixing at an arbitrary ratio.

The amount of the tackifier resin emulsion of the present invention to be used in the rubber-based latex is 10 to 150 parts by weight (solid content) per 100 parts by weight (solid content) of the rubber-based latex. (Equivalent amount). In particular, the lower limit is preferably 25 parts by weight and the upper limit is preferably 100 parts by weight. If the amount of the tackifying resin emulsion is less than 10 parts by weight, it is difficult to impart sufficient adhesive strength. If the amount exceeds 150 parts by weight, not only the adhesive strength is reduced but also the adhesive becomes hard, and the tackiness increases. Also tend to decrease.

The water-based pressure-sensitive adhesive composition of the present invention may contain an antifoaming agent, a thickening agent, a filler, an antioxidant, a water-proofing agent, a film-forming aid and the like, if necessary.

[0029]

EXAMPLES The present invention will be described in more detail with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples. In each example, all parts and percentages are by weight unless otherwise specified.

Production Example 1 (Production of acrylic polymer emulsion) (1) 44.46 parts of water (2) Anionic emulsifier (trade name: Hytenol S, solid content: 50%, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 0.90 parts (3) 43.90 parts of acrylic acid butyl ester and 1.36 parts of acrylic acid (4) 0.23 part of catalyst (potassium persulfate), 0.11 part of pH adjuster (heavy sodium) and water 9 .04 parts In a four-necked flask equipped with a stirrer, a cooling tube, a dropping funnel and a nitrogen inlet tube, the above (1) and (2) were dissolved under a nitrogen gas stream at 70 ° C., and then the above solution was stirred. (3)
1/10 of the total of (4) and (4) were added, and a preliminary reaction was performed at 70 ° C. for 30 minutes under a nitrogen gas stream.
9/10 of the total of (3) and (4) was added dropwise over 2 hours to carry out dropwise polymerization. After dropping the total amount of (3) and (4), the reaction was completed at 70 ° C. for 1 hour, cooled to room temperature, taken out while performing 100 mesh wire mesh filtration, and an acrylic polymer having a solid content of 45.7%. Emulsion was obtained.

Production Example 2 (Production of tackifier resin) (1) Disproportionation treatment Acid value 172, softening point (measured by ring and ball method specified in JIS K 5902, the same applies hereinafter) 75 ° C., color tone Gardner Color 6 Refined gum rosin 1000 from China
g as a catalyst containing 5% palladium-containing carbon (hereinafter referred to as 5%).
% Palladium carbon) (water content 50%) 0.3
g was added thereto, and a disproportionation reaction was carried out while stirring at 280 ° C. for 4 hours in a nitrogen stream to obtain disproportionated rosin having an acid value of 157, a softening point of 77 ° C. and a color tone Gardner Color 8.

(2) Purification Treatment The disproportionated rosin was distilled under a reduced pressure of 3 mmHg in a nitrogen stream, and the obtained main fraction was used as purified disproportionated rosin. Table 1 shows the distilling temperature and the temperature in the kettle at the time of purification, and the acid value and the yield of the first fraction, the main fraction and the rosin in the bottom.

[0033]

[Table 1]

(3) Esterification reaction Purified disproportionated rosin (main fraction) 500 having an acid value of 178, a softening point of 83 ° C., and a color tone of Gardner Color 4 obtained by distillation.
g in a 1-liter four-necked flask, heated to 180 ° C. under a nitrogen stream, added with 70 g of glycerin at 200 ° C. under melting and stirring, then heated to 280 ° C., and subjected to an esterification reaction at the same temperature for 12 hours. And an acid value of 3.1 and a hydroxyl value of 20.
2. A purified disproportionated rosin ester having a softening point of 90 ° C. and a color tone of Gardner Color 5 was obtained.

(4) Dehydrogenation treatment 200 g of the purified disproportionated rosin ester and 1 g of 5% palladium carbon were charged into a 1-liter immersion-type autoclave, and oxygen in the system was removed. The pressure was increased to 2.5 kg / cm ² , the temperature was raised to 270 ° C., dehydrogenation was performed at the same temperature for 3 hours, and the acid value was 7.6 and the hydroxyl value was 2
A rosin ester having a 0.0, a softening point of 91 ° C. and a color tone Gardner color of 1 or less (Hazen color 150) was obtained.

Production Example 3 (Production of tackifying resin) 200 g of the purified disproportionated rosin ester obtained in Production Example 2 (3) and 5% palladium carbon (water content: 50%)
%) Was charged into a 1-liter immersion autoclave, oxygen in the system was removed, and then the system was hydrogenated with 100%.
Pressurized temperature was raised to 270 ° C. in Kg / cm ^2, 3 at the same temperature
After hydrogenation for an hour, an acid value of 7.8, a hydroxyl value of 21.0,
A rosin ester having a softening point of 89 ° C. and a color tone Gardner color of 1 or less (Hazen color 60) was obtained.

Production Example 4 (Production of tackifying resin) (1) Hydrogenation treatment An acid value of 171 and a softening point of 76 were added to a 3-liter autoclave.
C., 1000 g of unrefined Chinese gum rosin having a color tone of Gardner Color 6 and 2 g of 5% palladium carbon (water content: 50%) as a dehydrogenation catalyst were removed, and oxygen in the system was removed. After pressurizing to ² cm ² , the mixture was heated to 260 ° C. with stirring and hydrogenated at the same temperature for 3 hours to obtain unpurified hydrogenated rosin having an acid value of 167, a softening point of 74 ° C., and a color tone of Gardner Color 5.

(2) Purification treatment The hydrogenated rosin was distilled under a reduced pressure of 3 mmHg in a nitrogen stream, and the obtained main fraction was used as purified hydrogenated rosin. Table 2 shows the distilling temperature and the temperature in the kettle at the time of the purification, and the acid value and the yield of the first fraction, the main fraction and the residual rosin.

[0039]

[Table 2]

(3) Esterification reaction 500 g of purified hydrogenated rosin having an acid value of 175.2, a softening point of 83.degree.
In a flask of 1 liter, the temperature was raised to 180 ° C. under a nitrogen stream, 69 g of glycerin was added at 200 ° C. under melt stirring, then the temperature was raised to 280 ° C., and the esterification reaction was carried out at the same temperature for 12 hours. A purified hydrogenated rosin ester having a value of 7.0, a hydroxyl value of 21.2, a softening point of 90 ° C., and a color tone of Gardner Color 3 was obtained.

(4) Dehydrogenation treatment 200 g of the purified hydrogenated rosin ester and 1 g of 5% palladium carbon were charged in a 1-liter immersion-type autoclave, and oxygen in the system was removed. The pressure was increased to 5 kg / cm ² , the temperature was raised to 270 ° C., dehydrogenation was performed at the same temperature for 3 hours, and the acid value was 8.5 and the hydroxyl value was 2
A rosin ester having a 2.0, a softening point of 90 ° C. and a color tone Gardner color of 1 or less (Hazen color 100) was obtained.

Production Example 5 (Production of tackifying resin) 500 g of the purified hydrogenated rosin obtained in Production Example 4 (2) and 2 g of 5% palladium carbon (water content: 50%) were added in 1 part.
Take in a liter flask, raise the temperature to 180 ° C under a stream of hydrogen, add 69 g of glycerin at 200 ° C under melt stirring, raise the temperature to 270 ° C, and conduct the esterification reaction and dehydrogenation at the same temperature for 12 hours. Were carried out simultaneously to obtain a rosin ester having an acid value of 3.7, a hydroxyl value of 20.0, a softening point of 90 ° C. and a color tone Gardner color of 1 or less (Hazen color 150).

Production Example 6 (Production of Tackifying Resin) (1) Purification Treatment Unpurified Chinese gum rosin having an acid value of 171 and a softening point of 74 ° C. and a color tone of Gardner Color 6 was distilled under a reduced pressure of 3 mmHg in a nitrogen stream. The main fraction obtained under the conditions in Table 3 was used as purified rosin.

[0044]

[Table 3]

(2) Addition reaction A reaction vessel was charged with 660 g of the purified rosin obtained by the above-mentioned distillation and 15 g of acrylic acid, and stirred under a stream of nitrogen for 2 hours.
The reaction was carried out at 20 ° C. for 4 hours, and then the unreacted substances were removed under reduced pressure to obtain an addition reaction product.

(3) Esterification reaction 500 g of the addition reaction product and pentaerythritol 7
Charge 2.5 g, gradually raise the temperature under a nitrogen stream,
The reaction was carried out at a temperature of 12 ° C. for 12 hours with stirring under stirring to obtain an esterified product.

(4) Hydrogenation Further, 200 g of the esterified product and 2.0 g of 5% palladium carbon (water content: 50%) were charged into a 1-liter immersion autoclave to remove oxygen from the system. Pressurized to 100 kg / cm ² with hydrogen, heated to 220 ° C., hydrogenated at the same temperature for 3 hours, acid value 16.5, hydroxyl value 30.5, softening point 114 ° C., color tone Gardner color 1 or less ( A rosin ester of Hazen color 100) was obtained.

Production Example 7 (Production of Tackifying Resin) Purified disproportionated rosin 200 obtained in Production Example 2 (2) above
g and 5% palladium carbon (water content 50%) 0.2g
Was charged in a 1-liter shaking autoclave, oxygen in the system was removed, and the system was then filled with hydrogen at 0.5 kg / cm ^2.
Then, the temperature was raised to 275 ° C., and a dehydrogenation reaction was performed at the same temperature for 3 hours to obtain a rosin having an acid value of 175, a softening point of 87 ° C. and a color tone Gardner color of 1 or less (Hazen color 150).

Production Example 8 (Production of tackifying resin) Purified disproportionated rosin 200 obtained in Production Example 2 (2) above
g and 5% palladium carbon (water content 50%) 0.4g
Was charged in a 1-liter shaking autoclave, oxygen in the system was removed, and the system was pressurized to 50 kg / cm ² with hydrogen, heated to 255 ° C., and subjected to a hydrogenation reaction at the same temperature for 3 hours. A rosin having an acid value of 177, a softening point of 86 ° C. and a color tone Gardner color of 1 or less (Hazen color 50) was obtained.

Example 1 (1) (Production of tackifying resin emulsion) 100 parts of the colorless rosin ester obtained in Production Example 2 (4) was dissolved in 60 parts of toluene at 100 ° C for about 1 hour, and
After cooling to 3 ° C., 3 parts of an anionic emulsifier (sodium dodecylbenzenesulfonate) in terms of solid content and water 16
0 parts were added, and the mixture was vigorously stirred at 75 ° C. for 1 hour to perform preliminary emulsification. The obtained pre-emulsion was emulsified at a pressure of 300 kg / cm ² with a high-pressure emulsifier (manton gauulin) to obtain an emulsion. Next, 200 parts of the emulsion was charged into a vacuum distillation apparatus, and vacuum distillation was performed at 50 ° C. and 100 mmHg for 6 hours to obtain a tackifier resin emulsion having a solid content of 50%.

10 parts (in terms of solid content) of the tackifying resin emulsion obtained in the above (1) and 90 parts (in terms of solid content) of the acrylic polymer emulsion obtained in Production Example 1 were mixed. Primal ASE-60 as a thickener
0.5 part (made by Nippon Acrylic Co., Ltd.) (in terms of solid content) was added, and the mixture was thickened with aqueous ammonia to obtain an aqueous pressure-sensitive adhesive composition.

Examples 2 to 7 and Comparative Examples 1 and 2 The procedure of Example 1 was repeated, except that the type of the tackifier resin was changed as shown in Table 4, and a tackifier resin emulsion was prepared. The same procedure as in Example 1 was carried out to produce a water-based pressure-sensitive adhesive composition.

Comparative Example 3 90 parts (in terms of solid content) of the acrylic polymer emulsion obtained in Production Example 1 were mixed with 0.5 parts of Primal ASE-60 (manufactured by Nippon Acrylic Co., Ltd.) as an acrylic thickener (solid content). (Converted to water) and thickened with aqueous ammonia to obtain an aqueous pressure-sensitive adhesive composition.

(Evaluation of Performance) The water-based pressure-sensitive adhesive compositions prepared in the respective Examples and Comparative Examples were applied to a 40-μm-thick polyester film so that the paste thickness after drying was 25 μm, and circulatingly dried at 105 ° C. After drying in a vessel for 3 minutes, an adhesive sheet was prepared. The following various tests were performed on the obtained pressure-sensitive adhesive sheet. Table 4 shows the results.

(Adhesive force): At a measurement temperature of 20 ° C., the adhesive force (g / inch) when peeled at 180 ° at a tensile speed of 300 mm / min was measured. The adherend is a polyethylene plate.

(Tack): described in J. Z. 0237 According to the Dow method, the inclination is 30 degrees and the measurement temperature is 20
Measured in ° C. The numerical values in Table 4 indicate the ball numbers. Is shown.

(Weather resistance): Xenon light / irradiation energy: 765 W / cm ² (300 to 800)
nm), illuminance: 150 Klx, spectral distribution: CIE N
o. Approximately 20, lamp used: 1.1 kW Xenon lamp｝ The appearance change (coloring) after irradiation for 24 hours was visually determined. ◎: colorless and transparent ○: very slightly colored yellow △: slightly colored yellow ×: colored yellow

[0058]

[Table 4]

Claims (10)

[Claims] 1. A tackifying resin emulsion comprising a resin emulsion obtained by emulsifying a colorless rosin and / or a colorless rosin ester having a Gardner color of 2 or less in the presence of an emulsifier. 2. The adhesive according to claim 1, wherein the colorless rosin is a rosin obtained by subjecting a purified rosin or a rosin purified, disproportionated or hydrogenated to a dehydrogenation treatment. Application resin emulsion. 3. The tackifier according to claim 1, wherein the colorless rosin is a rosin obtained by subjecting a purified rosin or a rosin purified and disproportionated or hydrogenated to a hydrogenation treatment. Resin emulsion. 4. The method according to claim 1, wherein the colorless rosin is purified rosin and α, β-unsaturated monocarboxylic acid and / or α, β-unsaturated monocarboxylic acid.
The tackifier resin emulsion according to claim 1, which is a rosin obtained by subjecting an addition reaction product with a β-unsaturated dicarboxylic acid to a hydrogenation treatment. 5. The method according to claim 5, wherein the colorless rosin ester is a rosin that is a purified rosin or a rosin that has been purified and disproportionated or hydrogenated, and dehydrogenated during or after the esterification reaction. 2. The tackifier resin emulsion according to claim 1, which is a rosin ester obtained by subjecting the emulsion to a rosin ester treatment. 6. The colorless rosin ester is obtained by using a purified rosin or a rosin subjected to a purification treatment, a disproportionation treatment or a hydrogenation treatment as rosins, and performing a hydrogenation treatment after the esterification reaction. The tackifier resin emulsion according to claim 1, which is a rosin ester obtained. 7. The above-mentioned colorless rosin ester is obtained by using, as rosins, an addition reaction product of purified rosin and α, β-unsaturated monocarboxylic acid and / or α, β-unsaturated dicarboxylic acid. The tackifier resin emulsion according to claim 1, which is a rosin ester obtained by subjecting a hydrogenation treatment to a rosin ester after the reaction. 8. A water-based pressure-sensitive adhesive composition comprising an acrylic polymer emulsion or a rubber-based latex, and the tackifier resin emulsion according to any one of claims 1 to 7. 9. The water-based pressure-sensitive adhesive composition according to claim 8, wherein 2 to 40 parts by weight (solid content) of the tackifier resin emulsion is blended with 100 parts by weight (solid content) of the acrylic polymer emulsion. Stuff. 10. A tackifier resin emulsion of 10 to 1 part by weight based on 100 parts by weight of rubber-based latex (in terms of solid content).
The aqueous pressure-sensitive adhesive composition according to claim 8, wherein 50 parts by weight (in terms of solid content) is blended.