JP5116239B2 - Method for producing emulsion-type pressure-sensitive adhesive composition, and pressure-sensitive adhesive composition - Google Patents

Description

  The present invention relates to a method for producing an emulsion-type pressure-sensitive adhesive composition. More specifically, the emulsion-type pressure-sensitive adhesive composition has a high non-volatile content, hardly generates aggregates at the time of polymerization, has excellent emulsion standing stability, and is used as a pressure-sensitive adhesive. The present invention relates to a method for producing an emulsion-type pressure-sensitive adhesive composition having excellent adhesion (particularly adhesion to polyolefin) and retention (particularly retention at high temperatures and retention under wet heat).

  The acrylic ester copolymer emulsion can be used as an adhesive or a pressure-sensitive adhesive because the balance of adhesiveness and cohesive force can be changed by changing the composition. And in this case, in order to improve adhesiveness, adding tackifying resin is performed widely.

  However, since the tackifying resin is insoluble in water, means such as a method in which it is dissolved in a solvent and a method in which it is emulsified in water and added as an emulsion are taken. However, these methods may lose the advantages of an aqueous system. Further, since the particles of the tackifying resin and the particles of the acrylic emulsion are not uniformly mixed, the obtained adhesive or pressure-sensitive adhesive has a problem that sufficient adhesiveness cannot be obtained and the water resistance is lowered.

  In order to solve such a problem, several methods for introducing a tackifying resin into an emulsion-type pressure-sensitive adhesive have been proposed. For example, an acrylic monomer, a crosslinkable functional group-containing copolymerizable monomer, A water-dispersed adhesive composition (see, for example, Patent Document 1) obtained by emulsion polymerization of an emulsion containing a high molecular compound preliminarily dissolved in at least one and a surfactant, and a crosslinkable monomer and (meth) A blend in which a tackifying resin is dissolved or dispersed in a mixture of acrylates, or an emulsion blend in which this blend is dispersed in an aqueous polymerization solution containing an emulsifier, and an aqueous polymerization solution containing water, an emulsifier and a polymerization initiator. A copolymer emulsion type adhesive (see, for example, Patent Document 2) obtained by performing polymerization while continuously adding has been proposed.

  However, since these methods perform polymerization using an emulsified liquid emulsified and dispersed by an ordinary method, the polymerization becomes unstable when the amount of the tackifying resin used is increased, and the standing stability of the resulting emulsion is lowered. was there.

  As a method for solving these problems, several production methods for controlling monomer oil droplets have been proposed. For example, after a tackifier resin and an oil-soluble initiator are dissolved in (meth) acrylic acid ester to form monomer oil droplets having an average particle size of 1 μm or less, emulsion polymerization is performed in the monomer oil droplets (for example, Patent Document 3), a method of performing emulsion polymerization in the presence of an initiator after dissolving a tackifier resin in (meth) acrylic acid ester to form monomer oil droplets having an average particle diameter of 1 μm or less (for example, , See Patent Document 4), a monomer oil droplet having an average particle size of 0.4 μm or less is formed using an anionic emulsifier obtained by dissolving a tackifying resin in (meth) acrylic acid ester, and then water-soluble. Methods have been proposed in which polymerization is performed while dropping into an aqueous polymerization solution containing an initiator and an anionic emulsifier (see, for example, Patent Document 5).

JP 54-233641 A JP 58-185668 A JP 2000-313865 A JP 2001-348551 A JP 2003-335805 A

  On the other hand, in recent years, environmental issues such as sick houses have been highlighted, and adhesive tapes used in home interiors, home appliances, automobiles, etc., such as double-sided tapes and foam-based adhesive tapes, are solvent-based to water-based. The transition to solvent-free, such as emulsions, is being made rapidly. Under these circumstances, double-sided tapes and foam-based adhesive tapes are required to have a high non-volatile content in order to thicken the adhesive, and emulsion-type adhesives use water as a solvent. Therefore, emulsion type adhesives with low non-volatile content require a high-performance dryer, take time to dry, or need to be applied multiple times. An emulsion-type adhesive having a high nonvolatile content is desired.

  In the disclosed technique of Patent Document 3, the amount of tackifier resin used is not satisfactory in terms of polymerization stability, and in the disclosed technique of Patent Document 5, a polymerization aqueous solution in which an emulsifier is present in advance. The emulsion containing the tackifying resin with controlled particle size is dropped into the emulsion, and the emulsion polymerization is carried out. As a result, the monomer component of the emulsion is transferred to free emulsifier micelles and new particles are formed. Although the water resistance and the like are good, there are problems that the amount of the tackifying resin used is increased or the polymerization stability is lowered when the nonvolatile content is increased.

Furthermore, in the disclosed technique of the above-mentioned Patent Document 4, although it is relatively compatible with polymerization stability and various physical properties, that is, adhesiveness (particularly adhesiveness to polyolefin), the thick coatability required in the market, In other words, there is still room for improvement in terms of high nonvolatile content. That is, the product form of the emulsion-type pressure-sensitive adhesive in the market generally includes a preservative / antifungal agent, an antifoaming agent, a resin emulsion as a base, from the viewpoints of handleability (workability), coating suitability, and long-term storage. Additives such as a wettability imparting agent, a leveling agent and a thickener are added. At this time, it is common to add various additives diluted (dissolved or dispersed) with water in order to avoid an addition shock or to improve workability. In order to obtain an emulsion-type pressure-sensitive adhesive composition having a high non-volatile content, it is desired to produce a base resin emulsion with a higher non-volatile content. In addition, further improvement in adhesiveness (particularly adhesiveness to polyolefin) and holding power (particularly holding power at high temperatures) is desired.

  That is, in Patent Documents 4 and 5, the non-volatile content is relatively low, and the thick coating property is not yet satisfactory, and in Patent Documents 3 and 5, the adhesive property is not yet satisfactory, and particularly for polyolefins. Adhesiveness is insufficient and further improvements are desired.

  Therefore, in the present invention, under such a background, the emulsion is allowed to stand for stability, and when used as a pressure-sensitive adhesive, adhesion (particularly adhesion to polyolefin), retention (particularly retention at high temperatures, and wet heat). A method for producing an emulsion-type pressure-sensitive adhesive composition with good polymerization stability, which has both excellent performance (under holding power) and excellent drying properties (thickness coating properties) due to high nonvolatile content, and It aims at providing the adhesive composition obtained by this manufacturing method.

  However, as a result of intensive studies to solve such problems, the present inventors have found that an ethylenically unsaturated monomer (A) mainly composed of (meth) acrylic acid ester (a1) and a tackifier resin (B The emulsion solution (D) obtained by emulsifying the oil-soluble component (C) containing the above in an aqueous medium using an emulsifier is polymerized in the presence of a polymerization initiator to produce an emulsion-type pressure-sensitive adhesive composition. In this case, by setting the static surface tension at 23 ° C. of the emulsion (D) to 35 mN / m or more, it is possible to obtain an emulsion-type pressure-sensitive adhesive composition having a high non-volatile content that is excellent in drying properties even when thickly applied. In addition, the present inventors have found that an emulsion-type pressure-sensitive adhesive composition excellent in emulsion stability and pressure-sensitive adhesive properties can be obtained, and the present invention has been completed.

  That is, the gist of the present invention is that an oil-soluble component (C) comprising an ethylenically unsaturated monomer (A) mainly composed of (meth) acrylic acid ester (a1) and a tackifier resin (B). The emulsion (D) emulsified with an emulsifier in an aqueous medium is polymerized in the presence of a polymerization initiator to give a high-concentration emulsion-type pressure-sensitive adhesive composition, particularly an emulsion having a nonvolatile content of 50% by weight or more. In the production of the pressure-sensitive adhesive composition, the emulsion (D) has a static surface tension at 23 ° C. of 35 mN / m or more in the method for producing an emulsion-type pressure-sensitive adhesive composition.

In the present invention, as the ethylenically unsaturated monomer (A), a monomer (a2) having crosslinkability can be given cohesive force by blending a crosslinking agent, and the molecular weight and the glass transition point of the resin. It is preferable at the point which can give cohesion force by adjustment of (Tg).
Moreover, when the content of the tackifying resin (B) is 15 to 40 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer (A), the pressure-sensitive adhesive properties such as adhesion to olefins are good. This is preferable.

Furthermore, in this invention, it is also preferable to include the neutralization process which makes pH of an emulsion 5-9 in the stage in which the polymerization rate of an ethylenically unsaturated monomer (A) is 95% or less, It is also preferable to use a nonionic emulsifier as the emulsifier of D).
In the present invention, the emulsion-type pressure-sensitive adhesive composition obtained by the above production method preferably further contains a crosslinking agent from the viewpoint of obtaining good pressure-sensitive adhesive properties.

According to the method for producing an emulsion-type pressure-sensitive adhesive composition of the present invention, the standing stability of the emulsion is excellent, the adhesiveness (particularly the adhesion to polyolefin) when used as a pressure-sensitive adhesive, and the holding power (particularly holding at high temperature). To obtain an emulsion-type pressure-sensitive adhesive composition with good polymerization stability, which has both excellent performance in terms of strength and holding power under wet heat and excellent drying properties (thickness coating properties) due to its high non-volatile content. be able to.

Hereinafter, the present invention will be specifically described.
In the present invention, (meth) acrylic acid is acrylic acid or methacrylic acid, (meth) acryl is acrylic or methacrylic, (meth) acryloyl is acryloyl or methacryloyl, and (meth) acrylate is acrylate or Each means methacrylate.

  As an ethylenically unsaturated monomer (A) used by this invention, it has (meth) acrylic acid ester (a1) as a main component, As this (meth) acrylic acid ester (a1), for example, , Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, isooctyl (meth) acrylate In addition to aliphatic (meth) acrylates such as n-octyl (meth) acrylate, alicyclic (meth) acrylates such as cyclohexyl (meth) acrylate, aromatic (meth) acrylates such as benzyl (meth) acrylate, dimethylamino Ethyl (meth) acrylate, -Methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, etc. are mentioned, among them methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl An aliphatic (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, such as (meth) acrylate, is preferably used.

  In addition, it is preferable that the ethylenically unsaturated monomer (A) contains a crosslinkable monomer (a2) because the cohesive force can be adjusted. Examples of (a2) include (1) carboxyl group-containing monomer, (2) carbonyl group, (3) hydroxyl group-containing monomer, (4) epoxy group-containing monomer, and (5) alkoxysilyl group-containing. Monomers, (6) monomers containing amide groups or methylol groups, (7) polyfunctional monomers, and the like.

(1) Examples of the carboxyl group-containing monomer include acrylic acid, acrylic acid dimer, methacrylic acid, crotonic acid, itaconic acid, maleic acid and the like.
(2) Examples of the carbonyl group-containing monomer include diacetone acrylamide, 2- (acetoacetoxy) ethyl (meth) acrylate, and allyl acetoacetate.
(3) Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate.
(4) Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.

  (5) Examples of the alkoxysilyl group-containing monomer include 2- (meth) acryloxyethyltrimethoxysilane, 2- (meth) acryloxyethyltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3 -(Meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyldimethylmethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, 3- (Meth) acryloxypropyldimethylethoxysilane, 3- (meth) acryloxypropyltrichlorosilane, 3- (meth) acryloxypropylmethyldichlorosilane, 3- (meth) acryloxypropyldimethylchlorosilane, 3- (meth) acryl Roxypropyltri Ropioxysilane, 3- (meth) acryloxypropylmethyldipropoxyoxysilane, 3- (meth) acryloxypropyltributoxysilane, 4- (meth) acryloxybutyltrimethoxysilane, 5- (meth) acryloxypentyltrimethoxy Silane, 6- (meth) acryloxyhexyltrimethoxysilane, 6- (meth) acryloxyhexyltriethoxysilane, 8- (meth) acryloxyoctyltrimethoxysilane, 10- (meth) acryloxydecyltrimethoxysilane, 12- (meth) acryloxydodecyltrimethoxysilane, 18- (meth) acryloxyoctadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldimethoxysilane, vinyl Methyl diethoxy silane, vinyl methyl dipropoxy silane.

  (6) Examples of the monomer containing an amide group or a methylol group include acrylamide, methacrylamide, N-methylol acrylamide, butoxy N-methylol acrylamide, and the like.

  (7) As a polyfunctional monomer, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, alkylene glycol di (meth) acrylate such as neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, di Dialkylene glycol di (meth) acrylate such as propylene glycol di (meth) acrylate, trialkylene glycol such as triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate ( ) Acrylate, polyethylene glycol di (meth) acrylate, polyalkylene glycol di (meth) acrylate such as polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methanetri (meth) acrylate, tetramethylol Examples include methanetetra (meth) acrylate, glycerine methacrylate acrylate, tris (meth) acryloyloxyphosphate, glycerin di (meth) acrylate, diallyl terephthalate, tetraallyloxyethane, divinylbenzene, tri (meth) allyl isocyanurate, and the like.

  Among these, acrylic acid, methacrylic acid, itaconic acid, 2-hydroxyethyl (meth) acrylate, glycidyl di (meth) acrylate, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxy Propylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, vinyltriethoxysilane, N-methylolacrylamide, diacetoneacrylamide, 2- (acetoacetoxy) ethyl methacrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (Meth) acrylate, tripropylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate Chromatography, tri ethylene glycol di (meth) acrylate, diallyl terephthalate, divinylbenzene and the like are particularly preferably used.

  In the present invention, a copolymerizable monomer (a3) can also be used. As the copolymerizable monomer (a3), acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, Examples include vinyl acetate, vinyl propionate, vinyl chloride, and alkyl vinyl ether.

  In the ethylenically unsaturated monomer (A), the content ratio of the (meth) acrylic acid ester (a1), the crosslinkable monomer (a2), and the copolymerizable monomer (a3) is: The (meth) acrylic acid ester (a1) is 50 to 99.9% by weight, the crosslinkable monomer (a2) is 0.1 to 20% by weight, and the copolymerizable monomer (a3) is 0 to 0%. It is preferably 49.9% by weight, more preferably 70 to 99.7% by weight of (meth) acrylic acid ester (a1), and 0.3 to 10% by weight of monomer (a2) having crosslinkability. The copolymerizable monomer (a3) is 0 to 29.7% by weight, particularly preferably the (meth) acrylic acid ester (a1) is 80 to 99.5% by weight, and a monomer having crosslinkability. (A2) is 0.5 to 5% by weight, copolymerizable monomer (a3) is 0 to 19.5% It is%.

  If the (meth) acrylic acid ester (a1) is less than the lower limit, sufficient adhesive force and tack tend not to be obtained. When the monomer (a2) having crosslinkability is less than the lower limit value, the holding power is lowered, and when it exceeds the upper limit value, the adhesive force and tack tend to be lowered. If the copolymerizable monomer (a3) exceeds the upper limit value, the adhesive strength and tack tend to decrease.

  The tackifier resin (B) used in the present invention may be any one that can be dissolved or dispersed in the ethylenically unsaturated monomer (A). For example, Superester A-75 (manufactured by Arakawa Chemical Co., Ltd.), Super Rosin esters such as Ester A-100 (manufactured by Arakawa Chemical Co., Ltd.), Superester A-125 (manufactured by Arakawa Chemical Co., Ltd.), Pencel D-125 (manufactured by Arakawa Chemical Co., Ltd.), Pencel D-135 (manufactured by Arakawa Chemical Co., Ltd.), Pencel Polymerized rosin esters such as D-160 (manufactured by Arakawa Chemical Co., Ltd.), Rikatak PCJ (manufactured by Rika Finetech Co., Ltd.), Nikanol HP-100 (manufactured by Mitsubishi Gas Chemical Company), Nikanol HP-150 (manufactured by Mitsubishi Gas Chemical Company), Nikanol Terpenes such as xylene resin such as H-80, YS Polystar T-115 (manufactured by Yashara Chemical Co., Ltd.), Mytec G125 (manufactured by Yashara Chemical Co., Ltd.) Examples include phenol resins, petroleum resins such as FTR-6120 (Mitsui Petrochemical Co., Ltd.), FTR-6100 (Mitsui Petrochemical Co., Ltd.), coumarone indene resin, terpene resin, styrene resin, ethylene / vinyl acetate resin, and the like. 1 type or 2 types or more can be used.

  Further, a styrene-butadiene block polymer, a styrene-isoprene block polymer, an ethylene-isoprene-styrene block polymer, a vinyl chloride / vinyl acetate polymer, an acrylic rubber, or the like called an elastomer can also be used.

  In this invention, although the said ethylenically unsaturated monomer (A) and tackifying resin (B) are mix | blended and an oil-soluble component (C) is formed, this compounding ratio is ethylenically unsaturated monomer ( A) The tackifier resin (B) is preferably 1 to 50 parts by weight, more preferably 15 to 40 parts by weight, and particularly preferably 20 to 35 parts by weight with respect to 100 parts by weight. If the tackifying resin (B) is less than the lower limit, sufficient adhesiveness, in particular, adhesion to polyolefin tends to be not obtained. If the upper limit is exceeded, polymerization becomes unstable and sufficient adhesion and tack are obtained. There is a tendency to become unusable.

  In emulsifying the oil-soluble component (C) comprising the ethylenically unsaturated monomer (A) and the tackifier resin (B) using an emulsifier in an aqueous medium, Although it will not specifically limit if it has a function which can be emulsified in an aqueous medium, For example, reactive (ionic or nonionic) surfactant, non-reactive (ionic or nonionic) surfactant, etc. Used alone or in combination. In particular, it is preferable to use an anionic emulsifier and a nonionic emulsifier together because the polymerization stability is improved. In view of water resistance, it is preferable to use a reactive surfactant.

  The reactive surfactant may be an ionic or nonionic surfactant having radical reactivity with the ethylenically unsaturated monomer (A). Examples of the reactive surfactant include the following general surfactants: Examples thereof include those having structures such as formulas (1) to (11).

[In the general formulas (1) to (11), R ₁ is an alkyl group, R ₂ is hydrogen or a methyl group, R ₃ is an alkylene group, n is an integer of 1 or more, and m and l are integers of 1 or more. (M + n = 3), X is any one of hydrogen, SO ₃ NH 4, and SO ₃ Na. ]

  Specific examples of the surfactant include ADEKA rear soap SE-10N (anionic), ADEKA rear soap SE-20N (anionic), ADEKA rear soap SR-10 (anionic), and ADEKA rear soap SR-20 ( Anionic), ADEKA rear soap NE-10 (nonionic), ADEKA rear soap NE-20 (nonionic), ADEKA rear soap NE-30 (nonionic), ADEKA rear soap NE-40 (nonionic), ADEKA rear Soap ER-10 (nonionic), Adeka soap ER-20 (nonionic), Adeka soap ER-30 (nonionic), Adeka soap ER-40 (nonionic), Adekalia soap SDX-730 (anion) ), Adeka Soap SDX-731 (anionic), Adeka Soap PP-70 (Anio) ), Adekalya soap PP-710 (anionic) [manufactured by Asahi Denka Co., Ltd.], Eleminol JS-2 (anionic), Eleminol JS-20 (anionic), Eleminol RS-30 (anionic) [Above, manufactured by Sanyo Chemical Co., Ltd.], Latemul S-180A (anionic), Latemul S-180 (anionic), Lateml PD-104 (anionic) [above, manufactured by Kao Corporation], Aqualon BC- 05 (anionic), Aqualon BC-10 (anionic), Aqualon BC-20 (anionic), Aqualon HS-05 (anionic), Aqualon HS-10 (anionic), Aqualon HS-20 (anionic) Aqualon RN-10 (nonionic), Aqualon RN-20 (nonionic), Aqualon RN-30 (nonionic), Quarron RN-50 (nonionic), Aqualon KH-05 (anionic), Aqualon KH-10 (anionic), New Frontier S-510 (anionic) [above, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.], Phosphino -Commercial products such as Ru TX (anionic) [manufactured by Toho Chemical Co., Ltd.].

  Examples of anionic emulsifiers having no reactivity include alkyl sulfates, alkylbenzene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl phosphates, and the like. Can be mentioned.

  Examples of the nonionic emulsifier having no reactivity include oxyethylene-oxypropylene block polymer, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, sorbitan fatty acid ester, polyoxyethylene fatty acid and the like.

Specifically, Adeka Pluronic L-31, Adeka Pluronic L-61, Adeka Pluronic L-62, Adeka Pluronic L-72, Adeka Pluronic L-101, Adeka Pluronic L-121, Adeka Pluronic L-122, etc. Series, Adeka Pluronic P series such as Adeka Pluronic P-103, Adeka Pluronic F-68, Adeka Pluronic F-88 such as Adeka Pluronic F-88, Adeka Pro-Cock TR-701, Adeka Pluronic TR-702 and other Adeka Pluronic TR Series [above, manufactured by Asahi Denka Co., Ltd.] and the like.

  The amount of the emulsifier used is preferably 0.5 to 10 parts by weight, more preferably 0.8 to 7 parts by weight, particularly preferably 100 parts by weight of the ethylenically unsaturated monomer (A). Is 1 to 5 parts by weight. If the emulsifier is less than the above lower limit, emulsion polymerization tends to be unstable, and if it exceeds the upper limit, it tends to cause substrate adhesion and adherend contamination.

  Next, an ethylenically unsaturated monomer (A) containing a (meth) acrylic acid ester (a1), a crosslinkable monomer (a2), and another copolymerizable monomer (a3); The oil-soluble component (C) comprising the tackifying resin (B) is emulsified in the aqueous medium using the emulsifier to prepare an emulsion (D), and the emulsion (D) is used as a polymerization initiator. The polymerization is carried out in the presence to produce an emulsion-type pressure-sensitive adhesive composition. A method for obtaining such an emulsion (D) will be described below.

As a preparation method of each component, it is preferable to prepare other components after dissolving the emulsifier in water.
It is preferable that the usage-amount of water is 40-120 weight part with respect to 100 weight part of total amounts of an ethylenically unsaturated monomer (A) and tackifying resin (B), More preferably, it is 60-100. Part by weight, particularly preferably 65 to 90 parts by weight. If the amount of water used is less than the lower limit, the emulsion has a high viscosity and the polymerization stability tends to decrease, and if the amount exceeds the upper limit, the monomer concentration of the resulting emulsion decreases, and the emulsion of the present invention In order to make the non-volatile content 50% by weight or more, a process for removing a large amount of water such as a dehydration process is required separately, which is not preferable in production.

  The emulsified liquid (D) in the present invention is obtained by emulsifying an oil-soluble component (C) comprising an ethylenically unsaturated monomer (A) and a tackifier resin (B) in an aqueous medium using an emulsifier. The static surface tension at 23 ° C. is 35 mN / m or more, preferably 38 mN / m or more, particularly preferably 39 mN / m or more. In the emulsion (D), if the static surface tension is less than the lower limit, a large amount of aggregates are produced during polymerization, and it is extremely difficult to produce on a large scale such as on-site production. The effect of the present invention cannot be obtained due to poor strength, particularly adhesion to polyolefin. This means that when the static surface tension of the emulsion (D) is less than the lower limit of the present invention, the emulsion polymerization frequently occurs, and particles containing no tackifying resin are produced, or the tackifying resin in the particles. This is presumed to be due to the uneven distribution of the mixture and the poor compatibility between the tackifying resin and the acrylic resin. In the present invention, the upper limit of the static surface tension of the emulsion (D) is usually preferably 55 mN / m, particularly preferably 50 mN / m, more preferably 45 mN / m. When the viscosity of the liquid (D) becomes high and workability deteriorates, or when the amount of the emulsifier used is small, the stability of the emulsion (D) tends to deteriorate and the polymerization stability tends to deteriorate.

  Although it does not specifically limit as a method of making static surface tension of an emulsified liquid (D) 35 mN / m or more, It can adjust by selecting the kind and quantity of an emulsifier, and / or changing the conditions of an emulsification process. it can. That is, the static surface tension of the emulsified liquid greatly depends on the amount of the emulsifier that is not involved in particle formation and is free in the system. The smaller the free emulsifier, the greater the static surface tension, and vice versa. If the type and amount of the emulsifier are the same, increasing the shear force reduces the particle size and decreases the amount of free emulsifier, resulting in an increase in static surface tension. However, since the emulsifying power varies depending on the type of emulsifier used, the optimum amount and conditions of the emulsifying treatment are different. For example, when using an emulsifier having a strong emulsifying power, the amount is reduced or / and the shearing force of the emulsifying treatment. The static surface tension can be adjusted to be 35 mN / m or more by a change such as increasing.

As a procedure for emulsification, each component is mixed, sufficiently stirred with an arbitrary stirring device, etc., and further subjected to treatment with increased shearing force. It is preferable to adjust so that it may become m or more. That is, once the emulsion (d) having a static surface tension of less than 35 mN / m is used, it is further emulsified and dispersed to obtain an emulsion (D) having a static surface tension of 35 mN / m or more. This is preferable in that phase inversion separation of the liquid hardly occurs. The adjustment of the plurality of stages is, for example, mixing each component, preliminarily emulsifying using a stirrer equipped with a stirring blade such as a homodisper, paddle blade and the like, and further preliminarily emulsifying liquid (d1). It is emulsified and dispersed by a treatment with high shearing force to obtain an emulsion (d2) having a static surface tension of less than 35 mN / m. Thereafter, the emulsion is further emulsified and dispersed by a treatment with higher shearing force to obtain an emulsion (D) having a static surface tension of 35 mN / m or more.

  The treatment with high shearing force used when adjusting the emulsion (D) having a static surface tension of 35 mN / m or more is not particularly limited, but emulsification such as high-pressure homogenizer treatment, ultrasonic treatment, hydro shear, etc. Examples thereof include a method using an apparatus, and in particular, high-pressure homogenizer treatment is preferable, and an emulsion having a narrow particle size distribution can be obtained.

When using a high-pressure homogenizer, it is preferable that the number of passages (pass) of the pre-emulsified liquid (d1) through the high-pressure homogenizer is about 1 to 5, but when the ratio of the tackifying resin is increased as in the present invention. , The pre-emulsified liquid (d1) is phase-inverted when suddenly subjected to high-pressure treatment and cannot be emulsified in many cases. Therefore, the pre-emulsified liquid (d1) is first subjected to low-pressure treatment (150 kg / cm ² or less, preferably 100 kg / cm ² or less ) Once or a plurality of times and after passing through the emulsion (d2), a high-pressure treatment (180 kg / cm ² or more, preferably 200 kg / cm ² or more) is performed once or a plurality of times to obtain an emulsion (D). Is preferred.

  In measuring the static surface tension of the emulsion (d2) and / or emulsion (D), examples of the method include the Du Nui (Ring) method and the Will-Healmy (plate) method. The value of the static surface tension in is a value measured by the Du Nui (ring) method under the condition of 23 ° C.

  Moreover, the temperature at the time of emulsification has no problem as long as it is a temperature at which the mixture does not react during emulsification, and usually about 5 to 60 ° C. is appropriate.

  After preparing the above emulsion (D), the emulsion (D) is polymerized in the presence of a polymerization initiator. As a method for this, (1) the whole amount of the emulsion (D) is heated as it is. (2) The temperature of a part of the emulsion (D) is increased to initiate polymerization, and the remaining emulsion (D) (with a polymerization initiator added as needed) is added dropwise or dividedly. (3) After charging the reactor with water (some emulsifiers and polymerization initiators may be charged to such an extent that the polymerization stability is not affected) and raising the temperature, A method in which the emulsion (D) is added dropwise or dividedly and polymerized, and (4) a reactor is charged with a polymer emulsion (water and a polymerization initiator may be charged if necessary) and the temperature is raised. , A method in which the emulsion (D) is entirely dropped or dividedly added and polymerized, (5) the milk by the methods (1) to (4) above After reacting the liquid (D), an ethylenically unsaturated monomer, an emulsifier, and a method of polymerizing by adding dropwise or dividedly adding an emulsion mainly composed of water, and the like can be mentioned. The method (2), (3), (4), and (5) is preferable in terms of easy control, and the method (2), (4), and (5) is preferable because it is easy to obtain a high nonvolatile content. Is particularly preferred. In particular, it is not necessary to prepare another polymer emulsion or to prepare an emulsion different from the emulsion (D), and from the simplicity in the manufacturing process that only the emulsion (D) may be prepared (2 ) Is most preferred.

  The amount of the polymerization initiator used is preferably 0.05 to 5 parts by weight, more preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer (A). . If the polymerization initiator is less than the lower limit, the polymerization rate is slow, or the polymerization reaction does not proceed smoothly. If the upper limit is exceeded, the molecular weight of the resin tends to be low, and the holding power tends to decrease.

  The polymerization initiator is not particularly limited, and any water-soluble or oil-soluble one can be used. Specifically, alkyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, p- Methane hydroperoxide, isobutyl peroxide, laurolyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl Peroxide, di-t-butyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, di -Iso Organic peroxides such as tilperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, t-butylperoxyisobutyrate, azobisisobutyronitrile, dimethylazodiisobutyrate, 2,2-azobis ( 2,4-dimethylvaleronitrile), 2,2-azobis (2-methylbutyronitrile), potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, 4,4'-azobis-4-cyanovaleric Ammonium (amine) salt of acid, 2,2'-azobis (2-methylamidooxime) dihydrochloride, 2,2'-azobis (2-methylbutanamidoxime) dihydrochloride tetrahydrate, 2,2'-azobis {2-Methyl-N- [1,1-bis (hydroxymethyl) -2-hydro Cyethyl] -propionamide}, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], various redox catalysts (in this case, as the oxidizing agent, ammonium persulfate, potassium persulfate, Hydrogen peroxide, t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide and the like are used, and sodium sulfite, acidic sodium sulfite, Rongalite, ascorbic acid and the like are used as the reducing agent. Etc.

The polymerization initiator may be added in advance to the polymerization can, or may be added immediately before the start of polymerization, or the ethylenically unsaturated monomer (A) and tackifying resin before emulsification. You may add to the liquid mixture of (B) previously, or you may add to the emulsified liquid (D) after this emulsification.
Moreover, you may use a pH buffer together as needed for pH adjustment at the time of superposition | polymerization as needed.

Although it does not specifically limit as polymerization conditions in the said polymerization method, For example, in the method of (1), the temperature range of about 40-100 degreeC is suitable normally, and reaction was performed about 1 to 8 hours after temperature rising start. After (polymerization step), ripening is performed for about 1 to 3 hours at the same temperature (which may be different from the temperature of the polymerization step) (aging step).
In the method (2), 5 to 50% by weight of the emulsion (D) is polymerized at 40 to 90 ° C. for 0.1 to 4 hours, and then the remaining emulsion (D) is added for about 1 to 5 hours. The solution is dropped or dividedly added (polymerization step), and then aged for about 1 to 3 hours at the same temperature (may differ from the temperature of the polymerization step) (aging step).
In the method (3), water is charged so as to be 1 to 20% by weight of the emulsion (D), the temperature is raised to 40 to 90 ° C., and the emulsion (D) is dropped over about 2 to 5 hours. Add in portions (polymerization step), and then age at the same temperature (may differ from the temperature of the polymerization step) for about 1 to 3 hours (aging step).
In the method (4), the polymer emulsion is charged so as to be 5 to 50% by weight of the emulsion (D), heated to 40 to 90 ° C., and the emulsion (D) is dropped over about 2 to 5 hours. Alternatively, it is added in portions (polymerization step), and then ripened for about 1 to 3 hours at the same temperature (which may be different from the temperature of the polymerization step) (aging step).
In the method (5), after the polymerization is started at 40 to 90 ° C. for 0.1 to 8 hours so that the total amount of the emulsion (D) is 30 to 90% by weight of the total amount, the emulsion (D) is further added. Separately, a pre-emulsion liquid mainly composed of an ethylenically unsaturated monomer, an emulsifier and water is about 1 to 5 hours so that the total amount is 70 to 10% by weight (the whole is 100% by weight). Add dropwise or dividedly (polymerization step), and then ripen for about 1 to 3 hours at the same temperature (may differ from the temperature of the polymerization step) (aging step).

  Further, in the present invention, the polymerization stability is improved by neutralizing the pH of the emulsion to 5 to 9 when the polymerization rate of the emulsion particles during polymerization is 95% or less by the methods (1) to (5). It is desirable from the point of being favorable, More preferably, a polymerization rate is 70 to 95%, Most preferably, a polymerization rate is 85 to 95%. If the polymerization rate is less than 70%, the reactivity of the unreacted ethylenically unsaturated monomer (A) and the like tends to deteriorate, and the residual monomer amount tends to increase. Then, the stability of the particles tends to deteriorate.

In particular, in the methods (1) to (5), when the neutralization step is performed before the aging step, the polymerization rate is preferably in a preferable range. The polymerization rate is obtained from the formula 1) by measuring the nonvolatile content (N ₂ ) of the emulsion.

Formula 1) P = (N ₂ −N ₃ / N ₁ −N ₃ ) × 100
here,
P: polymerization rate (%)
N ₁ : Calculated non-volatile content of emulsion (%)
N ₂ : Actual value (%) of nonvolatile content of emulsion
N ₃ : Calculated non-volatile content other than the ethylenically unsaturated monomer (A) (%)

The above (N ₁ ) is a calculated value of the non-volatile content of the emulsion at the sampled stage, and is calculated from the raw materials charged up to that stage and is obtained from Equation 2). Further, (N ₂ ) is an actual measurement value of the nonvolatile content at the sampled stage, and is determined according to “JIS K 6828-1, Synthetic Resin Emulsion—Part 1: Determination of nonvolatile content, Condition B”. Further, (N ₃ ) is a non-volatile calculated value of components other than the ethylenically unsaturated monomer (A), and is calculated from the raw materials charged up to that stage, and is obtained from Equation 3).

Formula 2) N ₁ = [(A + B + C + D) / T] × 100
Formula 3) N ₃ = [(B + C + D) / T] × 100
here,
A: ethylenically unsaturated monomer (A) (part)
B: Tackifying resin (B) (part)
C: Nonvolatile content of emulsifier (D) (parts)
D: Non-volatile content value of other raw materials (other than A, B, C) (parts)
T: Total raw materials (parts)

  Thus, the emulsion-type pressure-sensitive adhesive composition of the present invention can be obtained. In the present invention, a high-concentration emulsion-type pressure-sensitive adhesive composition can be produced satisfactorily, and the emulsion usually has a nonvolatile content of 50% by weight or more. Preferably, 50 to 70% by weight can be obtained. In addition, even in a system containing a large amount of tackifying resin, it is possible to stably perform polymerization without generating cohesive force and coarse particles, and it is possible to produce an emulsion-type pressure-sensitive adhesive composition having excellent standing stability. it can.

  In the present invention, if necessary, an antiseptic / antifungal agent, an antifoaming agent, a thickening agent, a leveling agent, a wettability improving agent, a rust preventive agent, a freeze-thaw stabilizer, a plasticizer, a high boiling point solvent, a pigment. A filler or the like can be appropriately added to the obtained emulsion-type pressure-sensitive adhesive composition, or can be added before or during polymerization.

  In the present invention, in order to crosslink the functional group of the crosslinkable monomer (a2), the use of a crosslinking agent (preferably having at least two functional groups) can impart cohesive force. Examples of such crosslinking agents include (1) hydrazide compounds, (2) isocyanate compounds, (3) melamine compounds, (4) aziridine compounds, (5) epoxy compounds, and (6) oxazolines. Compound, (7) carbodiimide compound, (8) metal compound, (9) amino group-containing compound, and the like.

  (1) Examples of hydrazine compounds include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, and itaconic acid dihydrazide.

  (2) As isocyanate compounds, toluylene diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, metaxylylene diisocyanate, 1,5-naphthalene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated toluylene diene Isocyanate compounds such as isocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, tetramethylxylene diisocyanate, bullet polyisocyanate compounds such as “Sumidule N” (manufactured by Sumitomo Bayer Urethane Co., Ltd.), “Desmodur IL”, “Desmodur HL ”(Manufactured by Bayer AG) or“ Coronate EH ”(manufactured by Nippon Urethane Co., Ltd.). Polyisocyanate compounds, adduct polyisocyanate compounds such as “Sumijour L” (manufactured by Sumitomo Bayer Urethane Co., Ltd.), adduct polyisocyanate compounds such as “Coronate HL” (manufactured by Nippon Polyurethane Co., Ltd.), “Aquanate 100”, “Aquanate 110” ”,“ Aquanate 200 ”,“ Aquanate 210 ”(manufactured by Nippon Polyurethane Co., Ltd.), and the like.

(3) Examples of melamine compounds include hexamethoxymethylol melamine and methoxymethylol urea.
(4) Examples of the aziridine compound include “Chemite PZ-33” and “Chemite DZ-22E” (manufactured by Nippon Shokubai Co., Ltd.).

  (5) As the epoxy compound, "Denacol EX-611", "Denacol EX-612", "Denacol EX-614", "Denacol EX-614B", "Denacol EX-622", "Denacol EX-512" , "Denacol EX-521", "Denaconal EX-411", "Denacol EX-421", "Denacol EX-313", "Denacol EX-314", "Denacol EX-321", "Denacol EX-201", "Denacol EX-211", "Denacol EX-212", "Denacol EX-252", "Denacol EX-810", "Denacol EX-811", "Denacol EX-850", "Denacol EX-851", " "Denacol EX-821", "Denacol EX-830", "Denacol E -832 "," Denacol EX-841 "," Denacol EX-861 "," Denacol EX-911 "," Denacol EX-941 "," Denacol EX-920 "," Denacol EX-931 "(Nagase ChemteX Corporation) Product), diglycidyl aniline, diglycidyl amine, N, N, N ′, N′-tetraglycidyl m-xylenediamine, 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane and the like.

(6) Examples of oxazoline compounds include “Epocross WS-500”, “Epocross WS-700”, “Epocross K-2010E”, “Epocross K-2020E”, “Epocross K-2030E” (manufactured by Nippon Shokubai Co., Ltd.), and the like. Is mentioned.
(7) As the carbodiimide compound, “carbodilite V-02”, “carbodilite V-02-L2”, “carbodilite V-04”, “carbodilite V-06”, “carbodilite E-01”, “carbodilite E-02” (Nisshinbo Co., Ltd.).

  (8) Examples of metal compounds include metal alkoxides such as tetraethyl titanate, tetraethyl zirconate, and aluminum isopropionate, aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, zirconium, and the like. Examples thereof include acetylacetone and acetoacetate of polyvalent metals, metal chelate compounds of ethylenediaminetetraacetic acid coordination compounds, and metal complexes such as acetate-ammonium complex salts and ammonium-carbonate complex salts.

(9) As the amino group-containing compound, 1,3-diaminopropane, bis- (3-aminopropyl) ether, 1,2-bis- (3-aminopropoxy) ethane, 1,3-bis- (3 -Aminopropoxy) -2,2-dimethylpropane, 1,4-diaminobutane and the like.
As these crosslinking agents, those of an aqueous solution type, a water dispersion type or a self-emulsification type are particularly preferably used, and two or more kinds may be used in combination.

About content of a crosslinking agent, it is preferable that it is 0.01-20 weight part with respect to 100 weight part of acrylic resins in an acrylic resin emulsion, 0.05-15 weight part especially, Furthermore, it is 0.00. It is preferable that it is 1-10 weight part. If the content is less than the lower limit value, the physical property balance tends to deteriorate such as insufficient cohesive force, and if the content exceeds the upper limit value, the adhesive force tends to decrease.

  The emulsion-type pressure-sensitive adhesive composition obtained in the present invention is particularly used for pressure-sensitive adhesive products such as pressure-sensitive adhesive sheets, pressure-sensitive adhesive labels, and pressure-sensitive adhesive tapes, and particularly preferably used for double-sided tape applications, foam tape applications, pressure-sensitive adhesive label applications, and the like. .

  Thus, in the present invention, the oil-soluble component (C) comprising the ethylenically unsaturated monomer (A) having the (meth) acrylic acid ester (a1) as a main component and the tackifier resin (B) is used as an aqueous medium. The emulsified liquid is emulsified with an emulsifier to prepare an emulsion (D) having a static surface tension at 23 ° C. of 35 mN / m or more, and the emulsion (D) is polymerized in the presence of a polymerization initiator. Thus, in order to obtain an emulsion-type pressure-sensitive adhesive composition, even in a system having a high non-volatile content of the emulsion and containing a large amount of tackifying resin, there is almost no aggregate formation during polymerization, and the resulting emulsion is allowed to stand for stability. Further, it has an excellent effect on the adhesion of the film (particularly adhesion to polyolefin) and holding power (particularly holding power under high temperature and holding power under wet heat).

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
In the examples, “parts” and “%” mean weight basis unless otherwise specified.

Example 1
25 parts of 2-ethylhexyl acrylate, 66 parts of n-butyl acrylate, 6 parts of methyl methacrylate, 2 parts of acrylic acid, 1 part of diacetone acrylamide, and “Pencel D-135” (polymerized rosin-based tackifying resin: manufactured by Arakawa Chemical Co., Ltd.) A mixed solution containing 23 parts was prepared by mixing 88.2 parts of water with 0.6 parts of dibasic sodium phosphate, 2.8 parts of “Adekalia Soap SR-10” as an emulsifier, and “Adekalia Soap ER-10”. In addition to the aqueous solution in which 0.5 part was dissolved, preliminary emulsification was performed by stirring and mixing using a homodisper.

Subsequently, this preliminary emulsified liquid (d1) was subjected to 1 Pass treatment at a pressure of 70 kg / cm ² using a high-pressure homogenizer (manufactured by GAULIN, 15MR-8TA). The static surface tension of this emulsion (d2) was measured at 23 ° C. using the Du Nui (Ring) method and found to be 33.4 mN / m. Further, the emulsion (d2) was subjected to 1 Pass treatment at a pressure of 300 kg / cm ² to obtain 215.1 parts of an emulsion (D) having a static surface tension of 40.4 mN / m.
Further, 0.5 parts of ammonium persulfate (manufactured by Kishida Chemical Co., Ltd.) as a polymerization initiator was dissolved in 4.5 parts of water to prepare an initiator solution.

  Next, 3.7 parts of water and 43.7 parts of the emulsion (D) were charged in a stainless steel polymerization can. When the temperature was raised and the internal temperature reached 75 ° C., 10% of the initiator liquid was added. After adding and polymerizing at 75 ° C. for 30 minutes, the remaining emulsion (D) and 60% of the initiator solution were respectively dropped at 75 ° C. over 4.5 hours. Ten minutes after the completion of dropping, 4 parts of 10% aqueous ammonia was added to adjust the pH to 8. At this time, the polymerization rate before addition of ammonia water (before neutralization) was 90%. Furthermore, 30% of the initiator was added after 20 minutes, and then polymerization was carried out at the same temperature for 1.5 hours. Thereafter, the temperature was set to 55 ° C., 0.15 part of perbutyl H-69 (manufactured by NOF Corporation) diluted with 1.35 parts of water was added, and sodium bisulfite (manufactured by Wako Pure Chemical Industries, Ltd.) A solution obtained by diluting 0.15 part with 1.35 parts of water was added, followed by polymerization, followed by cooling to obtain an emulsion-type pressure-sensitive adhesive composition (I) (non-volatile content: 55%, viscosity: 500 mPa · s ( BM viscometer, 12 rpm, rotor No. 4, 23 ° C.), particle diameter 208 nm).

  Further, 0.1 part of the preservative “Biosite W-B350” (manufactured by Taisho Technos) diluted with 0.2 part of water and “SN Deformer JK” (manufactured by San Nopco) Adipic acid dihydrazide as a cross-linking agent is added by diluting 0.1 part with 0.2 part of water and 1 part of a wetting agent “SN Wet 970” (manufactured by San Nopco) diluted with 2 parts of water. (Otsuka Chemical Co., Ltd.) 0.4 part of water dispersed in 0.8 part of water was added, and “Adecanol UH-541” (manufactured by Asahi Denka Co., Ltd .; active ingredient 30%) as a thickener. 9 parts diluted with water 3.9 were added to obtain an emulsion-type pressure-sensitive adhesive composition (II) (non-volatile content 53%, viscosity 10500 mPa · s (BM type viscometer, 12 rpm, rotor No. 4, 23 ° C.)).

  The resulting emulsion-type pressure-sensitive adhesive composition (II) was evaluated for standing stability and aggregate amount as follows.

(Left stability)
The obtained emulsion-type pressure-sensitive adhesive composition (II) was allowed to stand at room temperature for 6 months, and the presence or absence of separation was observed. The evaluation criteria are as follows.
○ ・ ・ ・ No sediment or separation × ・ ・ ・ With sediment or separation

(Aggregate amount)
100 g of the obtained emulsion-type pressure-sensitive adhesive composition (II) was filtered through a 150 mesh nylon net, the filtered component (aggregate) was dried at 100 ° C. for 3 hours, and the weight of the aggregate was measured.

(Reaction can dirt)
The degree of soiling (adhered matter) of the reaction can after the produced emulsion-type pressure-sensitive adhesive composition (II) was extracted was visually observed. The evaluation criteria are as follows.
○: Almost no deposit △: Small amount of deposit ×: Many deposits

Moreover, the adhesive physical property of the obtained emulsion-type adhesive composition (II) was evaluated as follows.
(Adhesive strength to polyolefin)
The obtained emulsion-type pressure-sensitive adhesive composition (II) was applied onto a release paper so that the thickness after drying was 50 μm, dried at 100 ° C. for 5 minutes, and transferred to a 25 μm polyethylene terephthalate (PET) film. An adhesive film was prepared. The adhesive film was adhered to a polyethylene plate (Japanese test panel standard test plate) in an atmosphere of 23 ° C. and 50% RH, and the 180-degree peel strength was measured according to the method of measuring the adhesive strength of JIS Z 0237.

(Holding power)
The obtained emulsion was applied onto a release paper so that the thickness after drying was 50 μm, dried at 100 ° C. for 5 minutes, and transferred to a 25 μm PET film to prepare an adhesive film. The adhesive film was attached to a stainless steel plate (SUS304) so that the area was 25 mm × 25 mm, and (1) the condition of 40 ° C. × 80% RH, or (2) the condition of 80 ° C. A load of 1 kg was applied below, and the displacement (mm) after 24 hours of the film was measured according to the measuring method of the holding power of JIS Z 0237.

Example 2
In Example 1, the emulsifier (D) prepared by changing the emulsifier to 2.4 parts of “SR-10” and 0.4 parts of “ER-10” and adjusting the static surface tension to 41.2 mN / m was used. (Emulsion-type pressure-sensitive adhesive composition (I) (non-volatile content 55%, viscosity 450 mPa · s, particle size 225 nm)) and emulsion-type pressure-sensitive adhesive composition (II ) (Non-volatile content 53%, viscosity 10000 mPa · s).
Evaluation similar to Example 1 was performed about obtained emulsion type adhesive composition (II).

Example 3
In Example 1, after using a high pressure homogenizer (manufactured by GAULIN, 15MR-8TA) for ² Pass treatment at a pressure of 70 kg / cm ² , further 1 Pass treatment was performed at a pressure of 300 kg / cm ² to obtain a static surface tension of 41. The same procedure was performed except that the emulsion (D) prepared at 9 mN / m was used (polymerization rate 91% before neutralization), and emulsion-type pressure-sensitive adhesive composition (I) (non-volatile content 55%, viscosity 600 mPa · s, And an emulsion-type pressure-sensitive adhesive composition (II) (non-volatile content: 55%, viscosity: 11000 mPa · s).
Evaluation similar to Example 1 was performed about obtained emulsion type adhesive composition (II).

Example 4
In Example 1, a high pressure homogenizer (manufactured by GAULIN, 15MR-8TA) was used for 3 Pass treatment at a pressure of 70 kg / cm ² , followed by 1 Pass treatment at a pressure of 300 kg / cm ² , and a static surface tension of 43. The same procedure was performed except that the emulsion (D) prepared to 8 mN / m was used (polymerization rate 90% before neutralization), and emulsion-type pressure-sensitive adhesive composition (I) (non-volatile content 55%, viscosity 630 mPa · s, Particle size 195 nm) and an emulsion type pressure-sensitive adhesive composition (II) (non-volatile content 53%, viscosity 12000 mPa · s).
Evaluation similar to Example 1 was performed about obtained emulsion type adhesive composition (II).

Example 5
In Example 1, the emulsion (D) obtained by changing to 87.2 parts of water, 1.6 parts of “ADEKA rear soap SR-10” and 0.3 parts of “ADEKA rear soap ER-10” ( Using a static surface tension of 42.1 mN / m), the polymerization can was charged with 3.7 parts of water and 215.1 parts of the emulsion (D), and the temperature was raised to 75 ° C. At that time, 5% of the initiator solution was added, and polymerization was carried out at 75 ° C. for 2 hours. Thereafter, 65% of the remaining initiator solution was added dropwise at 75 ° C. over 2.5 hours for polymerization. Ten minutes after the completion of dropping, 4 parts of 10% aqueous ammonia was added to adjust the pH to 8. At this time, the polymerization rate before addition of ammonia water (before neutralization) was 89%. Furthermore, 30% of the initiator was added after 20 minutes, and then polymerization was carried out at the same temperature for 1.5 hours. Thereafter, the temperature was 55 ° C., 0.15 part of perbutyl H-69 diluted with 1.35 parts of water was added, and 0.15 part of sodium bisulfite was further diluted with 1.35 parts of water. The mixture was added to perform chasing polymerization, and then cooled to obtain an emulsion-type pressure-sensitive adhesive composition (I) (nonvolatile content: 55%, viscosity: 500 mPa · s, particle size: 210 nm).

Further, 0.1 part of the preservative “Biosite W-B350” (manufactured by Taisho Technos) diluted with 0.2 part of water and “SN Deformer JK” (manufactured by San Nopco) Adipic acid dihydrazide as a cross-linking agent is added by diluting 0.1 part with 0.2 part of water and 1 part of a wetting agent “SN Wet 970” (manufactured by San Nopco) diluted with 2 parts of water. (Otsuka Chemical Co., Ltd.) 0.4 part of water dispersed in 0.8 part of water was added, and “Adecanol UH-541” (manufactured by Asahi Denka Co., Ltd .; active ingredient 30%) as a thickener. A solution obtained by diluting 9 parts with water 3.9 was added to obtain an emulsion-type pressure-sensitive adhesive composition (II) (non-volatile content 53%, viscosity 10700 mPa · s).
Evaluation similar to Example 1 was performed about obtained emulsion type adhesive composition (II).

Example 6
In Example 1, an emulsion (D) prepared by setting “Pencel D-135” (polymerized rosin-based tackifier resin: manufactured by Arakawa Chemical Co., Ltd.) to 30 parts and a static surface tension of 39.7 mN / m was used. (Emulsion type adhesive composition (I) (non-volatile content 55%, viscosity 560 mPa · s, particle size 203 nm)) and emulsion type adhesive composition (II ) (Non-volatile content 53%, viscosity 11000 mPa · s).
Evaluation similar to Example 1 was performed about obtained emulsion type adhesive composition (II).

Example 7
In Example 1, using “Superester A-125” (rosin ester-based tackifier resin: Arakawa Chemical Co., Ltd.), an emulsion (D) prepared with a static surface tension of 40.0 mN / m was used. (Emulsion-type pressure-sensitive adhesive composition (I) (non-volatile content 55%, viscosity 580 mPa · s, particle size 200 nm)) and emulsion-type pressure-sensitive adhesive composition (II ) (Non-volatile content 53%, viscosity 11300 mPa · s).
Evaluation similar to Example 1 was performed about obtained emulsion type adhesive composition (II).

Example 8
In Example 1, an emulsion (D) prepared by using “Adeka Pluronic L-61” (manufactured by Asahi Denka Co., Ltd.) instead of “ER-10” as an emulsifier, and having a static surface tension of 41.0 mN / m. (Emulsion-type pressure-sensitive adhesive composition (I) (non-volatile content 55%, viscosity 490 mPa · s, particle size 212 nm)) and emulsion-type pressure-sensitive adhesive composition (II) (non-volatile content 53%, viscosity 9900 mPa · s) was obtained.
Evaluation similar to Example 1 was performed about obtained emulsion type adhesive composition (II).

Example 9
In Example 1, the same procedure was performed except that the timing of addition of 10% aqueous ammonia was changed from 10 minutes after the completion of dropping to 60 minutes later (the polymerization rate before neutralization was 94%). (I) (Nonvolatile content 55%, viscosity 500 mPa · s, particle diameter 205 nm) and emulsion type pressure-sensitive adhesive composition (II) (nonvolatile content 53%, viscosity 11200 mPa · s) were obtained.
Evaluation similar to Example 1 was performed about obtained emulsion type adhesive composition (II).

Comparative Example 1
In Example 1, using a high-pressure homogenizer (manufactured by GAULIN, 15MR-8TA), 1 Pass treatment was performed at a pressure of 30 kg / cm ² , and further 1 Pass treatment was performed at a pressure of 100 kg / cm ² to obtain a static surface tension of 34. The same procedure was performed except that the emulsion (D) prepared to 3 mN / m was used (polymerization rate 90% before neutralization), and emulsion-type pressure-sensitive adhesive composition (I) (non-volatile content 54%, viscosity 620 mPa · s, And an emulsion-type pressure-sensitive adhesive composition (II) (non-volatile content: 52%, viscosity: 15500 mPa · s).
Evaluation similar to Example 1 was performed about obtained emulsion type adhesive composition (II).
Table 1 shows the embodiments of the examples and comparative examples, and Table 2 shows the evaluation results.

In the present invention, it has a high non-volatile content, hardly generates aggregates at the time of polymerization, and is excellent in the standing stability of the emulsion, and when used as a pressure-sensitive adhesive (particularly, adhesion to polyolefin), holding power ( In particular, it is possible to obtain an emulsion-type pressure-sensitive adhesive composition excellent in holding power at high temperature and holding power under wet heat, and the obtained pressure-sensitive adhesive composition is particularly used for pressure-sensitive adhesive sheets, pressure-sensitive adhesive labels, pressure-sensitive adhesive tapes and the like. Used for adhesive products, especially suitable for double-sided tape applications, foam tape applications, adhesive label applications, and the like.

Claims (7)

  An oil-soluble component (C) comprising an ethylenically unsaturated monomer (A) mainly composed of (meth) acrylic acid ester (a1) and a tackifying resin (B) is used in an aqueous medium by using an emulsifier. When the emulsified emulsion (D) is polymerized in the presence of a polymerization initiator to produce an emulsion-type pressure-sensitive adhesive composition, the static surface tension at 23 ° C. of the emulsion (D) is 35 mN / m. It is the above, The manufacturing method of the emulsion type adhesive composition characterized by the above-mentioned.   The method for producing an emulsion-type pressure-sensitive adhesive composition according to claim 1, wherein the ethylenically unsaturated monomer (A) includes a monomer (a2) having crosslinkability.   The emulsion-type pressure-sensitive adhesive according to claim 1 or 2, wherein the content of the tackifying resin (B) is 15 to 40 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer (A). A method for producing an agent composition.   The emulsion according to any one of claims 1 to 3, further comprising a neutralization step of adjusting the pH of the emulsion to 5 to 9 when the degree of polymerization of the ethylenically unsaturated monomer (A) is 95% or less. For producing a mold pressure-sensitive adhesive composition.   A nonionic emulsifier is used as an emulsifier of an emulsified liquid (D), The manufacturing method of the emulsion-type adhesive composition in any one of Claims 1-4 characterized by the above-mentioned.   The adhesive composition obtained by the manufacturing method of the emulsion type adhesive composition in any one of Claims 1-5. The pressure-sensitive adhesive composition according to claim 6, further comprising a crosslinking agent.