JP2017014390A - Manufacturing method of water dispersion of acrylic polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a water dispersion of an acrylic polymer capable of forming a film having excellent durability under high temperature and high humidity and an emulsion type adhesive having excellent adhesive durability under high temperature and high humidity manufactured by the manufacturing method.SOLUTION: There is provided a manufacturing method of a water dispersion of an acrylic polymer by dissolving an acrylic block copolymer (I) having at least one polymer block (A) consisting of a methacrylic acid alkyl ester unit and at least one polymer block (B) consisting of an acrylic acid alkyl ester unit of 0.1 to 20 pts.mass in a monomer component containing at least one kind acrylic monomer (II) selected from (meth)acrylic acid ester and (meth)acrylic acid of 100 pts.mass and radical polymerizing the monomer component containing the acrylic monomer (II) with a state that the resulting solution is dispersed in water.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing an aqueous dispersion of an acrylic polymer, and more particularly to a method for producing an aqueous dispersion of an acrylic polymer capable of forming a film having excellent durability under high temperature and high humidity. The present invention also relates to an emulsion type adhesive comprising an aqueous dispersion of the acrylic polymer.

  Since acrylic polymers have excellent weather resistance, adhesive properties, etc., they have been studied in various forms, such as aqueous dispersions, for various uses, such as adhesives, coating agents, etc. ing.

  For example, an emulsion-type pressure-sensitive adhesive containing an acrylic block copolymer having a thiocarbonyl group has been studied (for example, see Patent Document 1). In addition, the use of an aqueous dispersion composed of a mixture of a block copolymer and a homopolymer or a random copolymer as a coating agent has been studied (for example, see Patent Document 2). Furthermore, an aqueous adhesive dispersion containing an acrylic block copolymer and / or a styrene block copolymer and an additive has been studied (for example, see Patent Document 3).

Japanese Patent Laid-Open No. 2003-147312 Special table 2011-506055 gazette Special table 2013-530287 Japanese Patent Publication No. 7-025859 JP-A-11-335432 JP-A-6-093060

Macromolecular Chemistry and Physics, 2000, 201, p. 1108 to 1114 “POLYMER HANDBOOK Forth Edition”, VII, Wiley Interscience, 1999, p. 675-714 “Properties of Polymers”, 3rd ed. Elsevier, 1990, p. 189-225

  Accordingly, an object of the present invention is to provide a method for producing an aqueous dispersion of an acrylic polymer capable of forming a film having excellent durability at a higher temperature and higher humidity than in the past.

According to the invention, the object is
[1] Acrylic block copolymer (I) having at least one polymer block (A) composed of alkyl methacrylate units and at least one polymer block (B) composed of alkyl acrylate units 0.1-20 mass parts is melt | dissolved in 100 mass parts of monomer components containing the at least 1 sort (s) of acrylic monomer (II) chosen from (meth) acrylic acid ester and (meth) acrylic acid, The solution obtained A method for producing an aqueous dispersion of an acrylic polymer in which a monomer component containing an acrylic monomer (II) is radically polymerized in a state of being dispersed in water;
[2] The acrylic block copolymer (I) is a diblock copolymer represented by the formula: (A)-(B) and a formula: (A)-(B)-(A). [Wherein (A) represents a polymer block (A) composed of alkyl methacrylate units, and (B) represents a polymer block (B) composed of alkyl acrylate units)] ,-Indicates a bond of each polymer block. A method for producing an aqueous dispersion of an acrylic polymer according to [1], which is at least one acrylic block copolymer selected from
[3] The method for producing an aqueous dispersion of an acrylic polymer as described in [1] or [2], wherein the acrylic block copolymer (I) has a molecular weight distribution of 1.0 to 1.5;
[4] The method for producing an aqueous dispersion of an acrylic polymer according to any one of [1] to [3], wherein the acrylic block copolymer (I) has a number average molecular weight of less than 100,000;
[5] The absolute value of the difference between the solubility parameter SP (B) of the polymer block (B) of the acrylic block copolymer (I) and the solubility parameter SP (II) of the acrylic monomer (II) is 0. 4 (J / cm ³ ) ^1/2 or less of the method for producing an aqueous dispersion of an acrylic polymer according to any one of [1] to [4];
[6] An aqueous dispersion of an acrylic polymer produced by the production method according to any one of [1] to [5] above;
[7] An emulsion-type adhesive comprising an aqueous dispersion of an acrylic polymer produced by the production method according to any one of [1] to [5] above;
Is achieved.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the aqueous dispersion of the acrylic polymer which can form the film | membrane which has the durability outstanding under high temperature and high humidity than before can be provided. The acrylic polymer aqueous dispersion produced by the production method of the present invention can be suitably used as an emulsion-type adhesive having excellent adhesion durability under high temperature and high humidity.

Hereinafter, the present invention will be described in detail. In this specification, methacryl and acryl may be collectively referred to as “(meth) acryl”. In addition, the pressure-sensitive adhesive and the adhesive may be collectively referred to as “adhesive”. In addition, materials that have both adhesive and adhesive properties, such as temporary fixing with adhesive during bonding work, and then designed to show practical strength by eventually increasing cohesion by some means and finally changing to adhesion The adhesive material thus prepared is also included in the “adhesive”.
As a raw material of the acrylic polymer aqueous dispersion obtained by the present invention, an acrylic block copolymer (I) and a monomer component containing an acrylic monomer (II) are used.

  The acrylic block copolymer (I) has at least one polymer block (A) composed of methacrylic acid alkyl ester units and at least one polymer block (B) composed of acrylic acid alkyl ester units. It is characterized by that. By using such an acrylic block copolymer (I), an aqueous dispersion of an acrylic polymer capable of forming a film having excellent durability under high temperature and high humidity can be obtained.

  Examples of the methacrylic acid alkyl ester that is a constituent unit of the polymer block (A) include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, and n-hexyl methacrylate. Cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, isobornyl methacrylate, and the like. Among these, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and n-butyl methacrylate are preferable, economically available, and the resulting polymer block (A) has excellent durability and weather resistance. Therefore, methyl methacrylate is more preferable.

  The methacrylic acid alkyl ester unit, which is a constituent unit of the polymer block (A), may be constituted by one kind alone, or may be constituted by two or more kinds. The proportion of the alkyl methacrylate unit contained in the polymer block (A) is preferably 60% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more in the polymer block (A). The polymer block (A) may be 100% by mass of methacrylic acid alkyl ester units.

  The polymer block (A) may contain other monomer units as long as the effects of the present invention are not impaired. Examples of such other monomers include methacrylic acid esters having no functional group other than methacrylic acid alkyl esters such as phenyl methacrylate and benzyl methacrylate; 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, and the like. Methacrylic acid alkoxyalkyl esters, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2-aminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, and the like; methacrylates having functional groups; Alkyl ester; Acrylic acid ester having no functional group other than acrylic acid alkyl ester such as phenyl acrylate and benzyl acrylate; 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, etc. Acrylic acid ester having a functional group such as alkoxyalkyl ester of crylic acid, diethylaminoethyl acrylate, 2-hydroxyethyl acrylate, 2-aminoethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate; (meth) acrylic acid , Vinyl monomers having a carboxyl group such as crotonic acid, maleic acid, maleic anhydride, fumaric acid, (meth) acrylamide, etc .; having a functional group such as (meth) acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride Vinyl monomers; aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, and m-methylstyrene; conjugated diene monomers such as butadiene and isoprene; ethylene, propylene, isobutene, Olefin-based monomers such as octene; ε- Caprolactone, lactone-based monomers such as valerolactone. When these monomers are used, they are usually used in a small amount, but are preferably 40% by mass or less, more preferably 20% by mass with respect to the total mass of the monomers used for forming the polymer block (A). % Or less, more preferably 10% by mass or less.

  The glass transition temperature of the polymer block (A) is preferably 25 ° C. or higher, more preferably 50 ° C. or higher, still more preferably 70 ° C. or higher, and particularly preferably 90 ° C. or higher. When the glass transition temperature of the polymer block (A) is within the above range, the resulting film made of an acrylic polymer tends to have excellent cohesive strength.

  The acrylic block copolymer (I) may contain two or more polymer blocks (A). In that case, the polymer blocks (A) may be the same or different. Also good.

  The weight average molecular weight (Mw) of the polymer block (A) is not particularly limited, but is preferably in the range of 1,000 to 50,000, and more preferably in the range of 2,000 to 35,000. More preferably, it is in the range of 4,000 to 25,000. When the weight average molecular weight (Mw) of the polymer block (A) is smaller than this range, there is a problem that the cohesive force of the film made of the acrylic polymer obtained is insufficient. Further, when the weight average molecular weight (Mw) of the polymer block (A) is larger than this range, the solubility in a monomer component containing an acrylic monomer (II) described later, The water dispersion may be inferior in handleability (storage stability, coatability, etc.). In addition, in this specification, Mw means the weight average molecular weight of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

  Examples of the acrylic acid alkyl ester that is a constituent unit of the polymer block (B) include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, Examples include cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, lauryl acrylate, tridecyl acrylate, stearyl acrylate, and the like.

  The alkyl acrylate unit that is a constituent unit of the polymer block (B) may be constituted by one kind alone, or may be constituted by two or more kinds. The proportion of acrylic acid alkyl ester units contained in the polymer block (B) is preferably 60% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more in the polymer block (B). The polymer block (B) may be 100% by mass of an acrylic acid alkyl ester unit.

The polymer block (B) may contain other monomer units as long as the effects of the present invention are not impaired. Examples of other monomers constituting such units include, for example, methacrylic acid alkyl esters and methacrylic acid alkyl esters other than methacrylic acid alkyl esters and methacrylic acid alkyl esters described in the polymer block (A), functional groups. Other than methacrylic acid ester having alkyl group, alkyl acrylate ester, acrylic ester having no functional group, acrylic ester having functional group, vinyl monomer having carboxyl group, vinyl monomer having functional group , Aromatic vinyl monomers, conjugated diene monomers, olefin monomers, lactone monomers, and the like. When these monomers are used, they are usually used in a small amount, but are preferably 40% by mass or less, more preferably 20% by mass with respect to the total mass of the monomers used for forming the polymer block (B). % Or less, more preferably 10% by mass or less.
The glass transition temperature of the polymer block (B) is preferably 0 ° C. or lower, more preferably −20 ° C. or lower, and further preferably −30 ° C. or lower.

  When the glass transition temperature of the polymer block (B) is within the above range, a film made of an acrylic polymer having excellent flexibility even in a low temperature region can be obtained. From the viewpoint that the glass transition temperature of the polymer block (B) is within the above preferred range and is easily available, among the alkyl acrylates, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, N-octyl acrylate is preferred.

  The acrylic block copolymer (I) may contain two or more polymer blocks (B). In that case, the polymer blocks (B) may be the same or different. Also good.

  The difference in glass transition temperature between the polymer block (A) and the polymer block (B) in the acrylic block copolymer (I) is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, and 100 ° C. The above is more preferable.

The acrylic block copolymer (I) has a general formula: when the polymer block (A) is (A) and the polymer block (B) is (B).
[(A)-(B)] n
[(A)-(B)] n- (A)
(B)-[(A)-(B)] n
[(A)-(B)] n-Z
[(B)-(A)] n-Z
(Wherein n represents an integer of 1 to 30 and Z represents a coupling site (a coupling site after a coupling agent reacts with a polymer terminal to form a chemical bond)). It is preferable. The value of n is preferably 1 to 15, more preferably 1 to 8, and further preferably 1 to 4. Among the above structures, the formula: [(A)-(B)] n, formula: [(A)-(B)] n-A, formula: B-[(A)-(B)] n The linear block copolymer is preferably a diblock copolymer represented by the formula: (A)-(B) or a triblock represented by the formula: (A)-(B)-(A) A block copolymer is particularly preferred.

  In the acrylic block copolymer (I), the content of the polymer block (A) is excellent in adhesion durability when the obtained aqueous dispersion of acrylic polymer is used as an emulsion type adhesive. From the point of view, it is preferably 5 to 55% by mass, and more preferably 10 to 35% by mass.

  From the viewpoint of excellent handleability (storage stability, coatability, etc.) of the resulting acrylic polymer aqueous dispersion, the acrylic block copolymer (I) has a number average molecular weight (Mn) of 20,000. It is preferably 300,000 or less, more preferably 30,000 or more and 200,000 or less, further preferably 40,000 or more and 150,000 or less, and further preferably 50,000 or more and 100,000 or less. When the number average molecular weight (Mn) of the acrylic block copolymer (I) exceeds 300,000, the solubility of the acrylic block copolymer polymer (I) in the monomer component containing the acrylic monomer (II) is low. Thus, it becomes difficult to produce an aqueous dispersion of an acrylic polymer. Moreover, when the number average molecular weight (Mn) of the acrylic block copolymer (I) is less than 20,000, the durability of the resulting film made of the acrylic polymer is lowered.

  In the acrylic block copolymer (I), the molecular weight distribution (Mw / Mn) is preferably 1.0 to 1.5, more preferably 1.0 to 1.3, 1.0 More preferably, it is -1.2. When Mw / Mn of the acrylic block copolymer (I) is in the above range, when used as an adhesive or the like, the cohesive force is high and the durability is excellent.

The production method of the acrylic block copolymer (I) is not particularly limited, and can be produced by a production method according to a known method. In general, as a method for obtaining a block copolymer having a narrow molecular weight distribution, a method of living polymerizing monomers as constituent units is employed. Examples of such living polymerization methods include a method of living polymerization using an organic rare earth metal complex as a polymerization initiator (see, for example, Patent Document 4), and an alkali metal or alkaline earth using an organic alkali metal compound as a polymerization initiator. A method of living anion polymerization in the presence of a mineral salt such as a metal salt (for example, see Patent Document 5), a method of living anion polymerization in the presence of an organoaluminum compound using an organic alkali metal compound as a polymerization initiator (for example, Patent Document 6), atom transfer radical polymerization method (ATRP) (see Non-Patent Document 1), and the like. Moreover, you may use a commercial item as acrylic type block copolymer (I). Examples of commercially available products include “Clarity (registered trademark) series” manufactured by Kuraray Co., Ltd.
The acrylic monomer (II) contained in the monomer component is composed of at least one selected from (meth) acrylic acid esters and (meth) acrylic acid.

  Examples of the (meth) acrylic acid ester to be the acrylic monomer (II) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, (meth) T-butyl acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, (meth) (Meth) acrylic acid alkyl esters such as tridecyl acrylate, stearyl (meth) acrylate and isobornyl (meth) acrylate; other than (meth) acrylic acid alkyl esters such as phenyl (meth) acrylate and benzyl (meth) acrylate Of (meth) acrylic acid ester without functional group; (meth) acrylic (Methoxy) acrylic acid alkoxyalkyl esters such as 2-methoxyethyl and (meth) acrylic acid 2-ethoxyethyl, diethylaminoethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- (meth) acrylic acid 2- Examples thereof include (meth) acrylic acid esters having a functional group such as aminoethyl, glycidyl (meth) acrylate, and tetrahydrofurfuryl (meth) acrylate.

The absolute value of the difference between the solubility parameter SP (B) of the polymer block (B) of the acrylic block copolymer (I) and the solubility parameter SP (II) of the acrylic monomer (II) is 0.4 ( J / cm ³ ) ^1/2 or less is preferable, 0.38 (J / cm ³ ) ^1/2 or less is more preferable, and 0.35 (J / cm ³ ) ^1/2 or less is preferable. More preferably. When the absolute value of the difference in solubility parameter is within the above range, the solubility of the acrylic block copolymer polymer (I) in the monomer component containing the acrylic monomer (II) is increased, and the acrylic polymer is dispersed in water. The production of the body is facilitated, and the durability of the film made of the acrylic polymer obtained is increased. The solubility parameter SP (B) of the polymer block (B) can be obtained by the estimation method of Hoftizer and Van Krebelen described in Non-Patent Document 2 (more specifically, Non-Patent Document 3). Further, the solubility parameter SP (II) of the acrylic monomer (II) can be determined by a method of calculating from the evaporation energy and molar molecular volume determined from the evaporation enthalpy described in Non-Patent Document 2, and VII of Non-Patent Document 2 Values described in Tables 7-9 of / 688-701 can be used.

The molar molecular volume in the monomer unit used for calculation of the solubility parameter SP (B) of the polymer block (B) can be determined by dividing the specific gravity of the polymer at 25 ° C. by the molecular weight of the monomer unit. For example, the molar molecular volume of poly (n-butyl acrylate) monomer units is determined to be 117.91 cm ³ / mol. Using this value, the solubility parameter of n-butyl polyacrylate is calculated to be 18.47 (J / cm ³ ) ^1/2 according to the estimation method of Hoftyzer and Van Krevelen.

  Moreover, when a polymer block (B) is a copolymer which consists of a some monomer unit, it can calculate by the following formula | equation (1).

（式（１）中、φ_iは重合体ブロック（Ｂ）中のモノマー単位（ｉ）の体積分率、ＳＰ（Ｂ）_iはモノマー単位（ｉ）からなる重合体の溶解度パラメーターを示す。）
アクリルモノマー（ＩＩ）が複数のモノマーからなる混合モノマーの場合は、以下の式（２）によって計算することができる。

(In the formula (1), φ _i represents the volume fraction of the monomer unit (i) in the polymer block (B), and SP (B) _i represents the solubility parameter of the polymer comprising the monomer unit (i).)
When the acrylic monomer (II) is a mixed monomer composed of a plurality of monomers, it can be calculated by the following formula (2).

（式（２）中、φ_jはモノマー（ｊ）の体積分率、ＳＰ（ＩＩ）_jはモノマー（ｊ）の溶解度パラメーターを示す。）

(In formula (2), φ _j represents the volume fraction of monomer (j), and SP (II) _j represents the solubility parameter of monomer (j).)

For example, when the polymer block (B) is composed of n-butyl acrylate, the acrylic monomer (II) includes methyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic A mixed monomer having a solubility parameter adjusted to a range of 18.07 to 18.87 (J / cm ³ ) ^1/2 by combining at least two monomers selected from 2-ethylhexyl acid and acrylic acid is preferable.

  The proportion of the acrylic monomer (II) contained in the monomer component is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more in the monomer component. The monomer component may be 100% by mass of acrylic monomer (II).

  The monomer component may contain a monomer other than the acrylic monomer (II). Examples of such other monomers include vinyl monomers having a carboxyl group other than (meth) acrylic acid such as crotonic acid, maleic acid, maleic anhydride, and fumaric acid; (meth) acrylamide, (meth) acrylonitrile Vinyl monomers having a functional group such as vinyl acetate, vinyl chloride, vinylidene chloride; aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene; butadiene, Examples thereof include conjugated diene monomers such as isoprene; olefin monomers such as ethylene, propylene, isobutene, and octene. When these monomers are used, they are usually used in a small amount, preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less in the monomer component.

  The acrylic block copolymer (I) is used in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the monomer component containing the acrylic monomer (II). In such a range, by using a monomer unit containing acrylic monomer (II) and an acrylic block copolymer, the aqueous dispersion of the acrylic polymer is highly uniform, and the aqueous dispersion has excellent storage stability. You can get a body. From the viewpoint of the durability of the film made of an acrylic polymer, the acrylic block copolymer (I) is used in an amount of 0.5 to 15 masses per 100 mass parts of the monomer component containing the acrylic monomer (II). It is preferably used in the range of 1 part by weight, and more preferably in the range of 1 to 10 parts by weight.

  In the acrylic polymer of the present invention, a solution obtained by dissolving the acrylic block copolymer (I) in a monomer component containing the acrylic monomer (II) is dispersed in water, It can be obtained by radical polymerization of a monomer component containing acrylic monomer (II).

  The method for dissolving the acrylic block copolymer (I) in the monomer component containing the acrylic monomer (II) is not particularly limited. For example, the acrylic block copolymer (I) is heated to about 30 to 60 ° C. as necessary, and the block copolymer (I) is added to the monomer component containing the acrylic monomer (II) with stirring. I) can be dissolved in the monomer component.

  The monomer component containing the acrylic monomer (II) is radically polymerized with the solution containing the acrylic block copolymer (I) and the monomer component obtained as described above dispersed in water. . Examples of the polymerization method include suspension polymerization method and emulsion polymerization method.

  Examples of the polymerization initiator used for the radical polymerization include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (2 -Imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (N, N ' -Dimethyleneisobutylamidine) 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-methylpropionamide) and other azo polymerization initiators; sodium persulfate, potassium persulfate, Persulfates such as ammonium persulfate; benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide t-amyl hydroperoxide, t- butyl perbenzoate, t- butyl peroxide peroxide initiators such as oxyacetate; and redox initiators such as persulfate and sodium hydrogen sulfite and the like. The usage-amount of the said polymerization initiator is 0.005-1 mass part normally with respect to 100 mass parts of total amounts of the monomer component containing acrylic monomer (II).

  When carrying out the radical polymerization, a chain transfer agent may be used for the purpose of adjusting the molecular weight of the resulting acrylic polymer. Examples of the chain transfer agent include α-methylstyrene dimer (such as 2,4-diphenyl-4-methyl-1-pentene), terpinolene, terpinene, dipentene, and alkyl mercaptan having 8 to 18 carbon atoms (for example, n-dodecyl). Mercaptans, etc.), C 8-18 alkylene dithiols, alkyl thioglycolates, dialkyl xanthogen disulfides, tetraalkyl thiuram disulfides, carbon tetrachloride and the like. The usage-amount of the said chain transfer agent is 0.001-0.5 mass part normally with respect to 100 mass parts of total amounts of the monomer component containing acrylic monomer (II).

  As a method for polymerizing a solution containing a monomer component in water in a dispersed state, an emulsion polymerization method is preferred from the viewpoint of excellent stability of the dispersion state of the solution containing the monomer component in water. In this emulsion polymerization method, an emulsifier is used. As the emulsifier, an emulsifier such as an anionic emulsifier, a nonionic emulsifier and a cationic emulsifier that can be used for the emulsion polymerization can be used.

  Examples of the anionic emulsifier include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecyl benzene sulfonate, polyoxyethylene alkyl ether sodium sulfate, polyoxyethylene alkyl phenyl ether ammonium sulfate, and methacryloyloxypolyoxypropylene sulfate sodium salt. .

  Examples of the nonionic emulsifier include polyoxyethylene alkyl ether and polyoxyethylene alkyl phenyl ether. These emulsifiers may be used alone or in combination of two or more. The usage-amount of the said emulsifier is 0.2-10 weight part normally with respect to 100 mass parts of total amounts of the monomer component containing acrylic monomer (II), Preferably it is 0.5-5 weight part.

The polymerization can be performed, for example, as follows.
Acrylic block copolymer (I) was dissolved in a monomer component containing acrylic monomer (II) in an aqueous medium (water or a mixed solvent of water-soluble organic solvent (for example, alcohol such as methanol) and water). A solution and, if necessary, an emulsifier are added, and a treatment with a homomixer, a treatment with ultrasonic waves, and the like are performed to prepare an emulsion. A polymerization initiator and, if necessary, a chain transfer agent are added to the emulsion, and the monomer component containing the acrylic monomer (II) is radically polymerized in a state where the solution containing the monomer component is dispersed in water. . In preparing the emulsion, a polymerization initiator and a chain transfer agent added as necessary may be mixed. Further, the polymerization initiator may be added all at once at the start of the reaction, or a part thereof may be added at the start of the reaction, and the rest may be added all at once or in divided portions during the radical polymerization reaction.

  The concentration of the monomer component in the aqueous medium during the radical polymerization is usually 20 to 75% by mass, preferably 40 to 75% by mass. The polymerization temperature in the radical polymerization is usually −5 to 100 ° C., preferably 30 to 90 ° C., and the polymerization time is usually 0.1 to 50 hours, preferably 2 to 10 hours.

  In this way, an aqueous dispersion of the acrylic polymer of the present invention is obtained. If necessary, an unreacted monomer component remaining in the aqueous dispersion, an organic solvent added as necessary, etc. In order to remove water, vacuum distillation or the like may be performed.

  Further, in the obtained aqueous dispersion of the acrylic polymer of the present invention, if necessary, other polymer, tackifier resin, softener, plasticizer, heat stabilizer, light stabilizer, antistatic agent, Flame retardants, foaming agents, colorants, dyeing agents, refractive index adjusting agents, fillers, antioxidants, UV absorbers, HALS, antifungal agents, anti-aging agents, crosslinking agents, neutralizing agents, thickeners, antifoaming Additives such as agents may be included. These additives are added to the aqueous dispersion after the production of the aqueous dispersion of the acrylic polymer of the present invention, or when the aqueous dispersion of the acrylic polymer of the present invention is produced, the acrylic monomer ( II) can be dissolved and added together with the acrylic block polymer (I).

  Examples of the other polymer include acrylic resins such as polymethyl methacrylate and (meth) acrylic acid ester copolymers; polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polybutene-1, poly-4- Olefin resins such as methylpentene-1 and polynorbornene; ethylene ionomers; polystyrene, styrene-maleic anhydride copolymer, high impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin, MBS resin, etc. Styrene resin of styrene; methyl methacrylate copolymer; polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polylactic acid; polyamide such as nylon 6, nylon 66, polyamide elastomer; polycarbonate; Polyvinylidene chloride; Polyvinyl alcohol; Ethylene-vinyl alcohol copolymer; Polyacetal; Polyvinylidene fluoride; Polyurethane; Modified polyphenylene ether; Polyphenylene sulfide; Silicone rubber modified resin; Acrylic rubber; Silicone rubber; SEPS, SEBS, SIS, etc. Styrenic thermoplastic elastomers; olefinic rubbers such as IR, EPR and EPDM. Among these, from the viewpoint of compatibility with the acrylic polymer contained in the aqueous dispersion, acrylic resin, ethylene-vinyl acetate copolymer, AS resin, polylactic acid, and polyvinylidene fluoride are preferable, and (meth) acrylic acid An ester copolymer (however, the above acrylic block copolymer (I) is not included) is more preferred.

  When the aqueous dispersion of the present invention contains a tackifying resin, for example, when used as an emulsion-type adhesive, it is preferable because adjustment of tack, adhesive force and holding force is facilitated. Examples of the tackifying resin include natural resins such as rosin resins and terpene resins; petroleum resins, hydrogenated (hereinafter sometimes referred to as “hydrogenated”) petroleum resins, styrene resins, and coumarone-indene resins. And synthetic resins such as phenol resins and xylene resins. Moreover, when it contains tackifying resin, as content, it is preferable that it is 1-100 mass parts with respect to 100 mass parts of acrylic polymers, and 3-70 mass parts from a viewpoint of adhesive force and durability. More preferably, it is more preferably 5 to 50 parts by mass, particularly preferably 5 to 40 parts by mass, and most preferably 5 to 35 parts by mass.

  Examples of the rosin-based resin include rosins such as gum rosin, tall oil rosin, and wood rosin; modified rosins such as hydrogenated rosin, disproportionated rosin, and polymerized rosin; Examples include rosin esters. Specific examples of the rosins include Pine Crystal KE-100, Pine Crystal KE-311, Pine Crystal KE-359, Pine Crystal KE-604, and Pine Crystal D-6250 (all manufactured by Arakawa Chemical Industries, Ltd.). It is done. Moreover, superesters E-720, E-650, NS-100H and NS-121 (all manufactured by Arakawa Chemical Industries, Ltd.), which are emulsions of rosin resins, can be mentioned.

  Examples of the terpene resin include terpene resins mainly composed of α-pinene, β-pinene, dipentene, etc., aromatic modified terpene resins, hydrogenated terpene resins, terpene phenol resins, and the like. Specific examples of the terpene resin include Tamorol 901 (Arakawa Chemical Industries, Ltd.). Moreover, Tamanol E-100 and E-200NT (both manufactured by Arakawa Chemical Industries, Ltd.), which are emulsions of terpene phenol-based resins, can be mentioned.

Examples such as the (hydrogenated) petroleum resin, for example, (hydrogenated) aliphatic (C ₅ series) petroleum resin, (hydrogenated) aromatic (C ₉ series) petroleum resin, (hydrogenated) copolymeric (C ₅ / C ₉ series) petroleum resin, (hydrogenated) dicyclopentadiene series petroleum resin, alicyclic saturated hydrocarbon resin and the like. Examples of the styrene resin include poly α-methylstyrene, α-methylstyrene / styrene copolymer, styrene monomer / aliphatic monomer copolymer, and styrene monomer / α-methyl. Examples thereof include styrene / aliphatic monomer copolymers, styrene monomer copolymers, and styrene monomer / aromatic monomer copolymers. Specific examples of the styrenic resin include FTR6000 series and FTR7000 series (manufactured by Mitsui Chemicals, Inc.).

  Among the above tackifying resins, rosin resins, terpene resins, (hydrogenated) petroleum resins and styrene resins are preferable in terms of expressing high adhesive force, and rosin resins are preferable from the viewpoint of improving adhesiveness, From the viewpoint of suppressing light deterioration, coloring, and generation of bubbles due to impurities, disproportionated or hydrogenated rosins purified by an operation such as distillation, recrystallization, or extraction are more preferable. These may be used alone or in combination of two or more. Moreover, about the softening point of the said tackifying resin, the thing of 50-150 degreeC is preferable from the point which expresses high adhesive force.

  Examples of the plasticizer include phthalates such as dibutyl phthalate, di-n-octyl phthalate, bis-2-ethylhexyl phthalate, di-n-decyl phthalate, diisodecyl phthalate, bis-2-ethylhexyl sebacate, di Fatty acid esters such as sebacic acid esters such as n-butyl sebacate, azelaic acid esters such as bis-2-ethylhexyl azelate, adipic acid esters such as bis-2-ethylhexyl adipate and di-n-octyl adipate; Paraffins such as chlorinated paraffins; Glycols such as polypropylene glycol; Epoxy polymer plasticizers such as epoxidized soybean oil and epoxidized linseed oil; Phosphate esters such as trioctyl phosphate and triphenyl phosphate Phosphites such as triphenyl phosphite; acrylic oligomers such as n-butyl poly (meth) acrylate and 2-ethylhexyl poly (meth) acrylate; polybutene; polyisobutylene; polyisoprene; process oil; naphthene System oil etc. are mentioned, These may be used independently and may use 2 or more types together.

  Examples of the filler include inorganic fibers such as glass fibers and carbon fibers and organic fibers; inorganic fillers such as calcium carbonate, talc, carbon black, titanium oxide, silica, clay, barium sulfate, and magnesium carbonate. When inorganic fibers and organic fibers are contained, durability is imparted to the resulting film made of an acrylic polymer. When the inorganic filler is contained, heat resistance and weather resistance are imparted to the resulting film made of the acrylic polymer.

  The acrylic polymer contained in the aqueous dispersion obtained by the present invention has excellent durability under high temperature and high humidity, for example, adhesive durability (holding power durability, adhesive strength durability, etc.). Therefore, for example, it can be suitably used as an emulsion type adhesive. The acrylic polymer of the present invention includes a component derived from the acrylic block copolymer (I) and a polymer component obtained mainly by radical polymerization of the monomer component containing the acrylic monomer (II). The component derived from the acrylic block copolymer (I) serves as a binder of a polymer component obtained mainly by radical polymerization of the monomer component containing the acrylic monomer (II), It is estimated that durability is improved.

  When the acrylic polymer aqueous dispersion obtained in the present invention is used for an emulsion-type adhesive, the content of the acrylic polymer in the aqueous dispersion is not particularly limited, but from the viewpoint of ease of handling, etc. The solid content in the aqueous dispersion is preferably in the range of 20 to 80% by mass, and more preferably in the range of 30 to 70% by mass.

When the above emulsion-type adhesive is used as an adhesive, it can be used as it is as a one-component adhesive, and can be applied to an adherend using a normal coating apparatus. The emulsion-type adhesive can be applied on a substrate or the like to form a film and used as an adhesive film. Adhesion is sufficient when the coated material is dried with hot air or energy such as (near) infrared rays or high frequency, and if necessary, it is cured at 40-60 ° C for 2-3 days after drying. It becomes an adhesive film exhibiting properties. The application amount of the above-mentioned adhesive when applied on a substrate or the like varies depending on the use, but is usually in the range of 1 to 500 g / m ² .
The emulsion-type adhesive is suitably used for an adhesive product in the form of an adhesive layer composed of the adhesive or a laminate including the adhesive layer.

  The laminate is obtained by laminating a layer formed from an emulsion-type adhesive (adhesive layer) and various substrates such as paper, cellophane, plastic material, cloth, wood and metal. . Since the acrylic polymer obtained in the present invention is excellent in transparency and weather resistance, it is preferable to use a base material layer made of a transparent material because a transparent laminate can be obtained. As a base material layer made of a transparent material, polyethylene terephthalate, triacetyl cellulose, polyvinyl alcohol, cycloolefin resin, styrene-methyl methacrylate copolymer, polypropylene, polyethylene, ethylene-vinyl acetate copolymer, polycarbonate, poly Examples include, but are not limited to, a polymer layer such as methyl methacrylate, polyethylene, or polypropylene, a mixture of two or more of these polymers, and a substrate layer made of glass. The polymer may be a copolymer obtained by copolymerizing various monomers.

  As a structure of the said laminated body, it is formed from the two-layer structure of the adhesive layer and base material layer which are formed from an emulsion type adhesive, for example, from two base material layers and an emulsion type adhesive. Three-layer configuration with the adhesive layer (base layer / adhesive layer / base layer), two different adhesive layers comprising a base layer and an emulsion-type adhesive (a ) And the adhesive layer (b) and the base material layer (base material layer / adhesive layer (a) / adhesive layer (b) / base material layer), base material layer Layer composition (base material layer / adhesive adhesion) of adhesive layer (a) formed from an emulsion type adhesive and an adhesive layer (c) composed of other materials and a base material layer Agent layer (a) / adhesive layer (c) / base material layer), three base material layers and two adhesive layers formed from an emulsion-type adhesive (base) Material layer / adhesive layer / base material layer / adhesive layer / base material layer) But it is lower, but the invention is not limited thereto.

  Although it does not restrict | limit especially as thickness ratio of the said laminated body, From the adhesiveness of an adhesive product obtained, durability, and a handleability, in the range of base material layer / adhesive agent layer = 1 / 1000-1000 / 1. It is preferable that it is within a range of 1/200 to 200/1.

  When producing the laminate, after forming the adhesive layer and the base material layer, respectively, they may be bonded together by a lamination method or the like, or by directly coating on the base material layer An agent layer may be formed.

  In the laminated body of this invention, in order to improve the adhesive force of a base material layer and an adhesive agent layer, you may give surface treatments, such as a corona discharge process and a plasma discharge process, to the surface of a base material layer previously. Moreover, you may form an anchor layer in the surface of at least one of the said adhesive agent layer and a base material layer using resin etc. which have adhesiveness.

  Examples of the resin used for the anchor layer include ethylene-vinyl acetate copolymers, ionomers, block copolymers (for example, styrene triblock copolymers such as SIS and SBS, diblock copolymers, etc.), ethylene -Acrylic acid copolymer, ethylene-methacrylic acid copolymer, modified polyolefin (for example, Admer (adhesive polyolefin manufactured by Mitsui Chemicals, Inc.)) and the like. The anchor layer may be a single layer or two or more layers.

When forming the anchor layer, the method is not particularly limited. For example, a method of forming the anchor layer by applying a solution containing the resin to the base material layer, a composition containing the resin to be the anchor layer, and the like. And a method of forming an anchor layer on the surface of the base material layer by T-die or the like after heating and melting.
The laminated body which has the said adhesive agent layer and a base material layer can also be used as a heat-sensitive adhesive film which used the adhesive layer as the heat-sensitive adhesive layer.

  The emulsion type adhesive obtained in the present invention can be used for various applications. Moreover, the adhesive layer which consists of this emulsion type adhesive agent can be used as a single adhesive sheet, and the laminated body containing this adhesive layer can also be applied to various uses. For example, for surface protection, masking, shoes, binding, packaging / packaging, office, labeling, decoration / display, bookbinding, bonding, dicing tape, sealing, anticorrosion / waterproof, medical・ For hygiene, glass scattering prevention, electrical insulation, electronic equipment holding and fixing, semiconductor manufacturing, optical display film, adhesive adhesive optical film, electromagnetic wave shielding, or electrical / electronic component sealing material An adhesive, an adhesive tape, a film, etc. are mentioned. Specific examples are given below.

  Adhesive for surface protection, adhesive tape or film, etc. can be used for various materials such as metal, plastic, rubber, wood, specifically, paint surface, metal plastic processing or deep drawing processing, It can be used to protect the surface of automobile members and optical members. Examples of the automobile member include a painted outer plate, a wheel, a mirror, a window, a light, and a light cover. Examples of the optical member include various image display devices such as a liquid crystal display, an organic EL display, a plasma display, and a field emission display; a polarizing film, a polarizing plate, a retardation plate, a light guide plate, a diffusion plate, an optical disc constituting film such as a DVD;・ Precise fine coated face plate for optical applications.

  Masking adhesives, tapes, films, etc. include: masking when manufacturing printed circuit boards and flexible printed circuit boards; masking when plating and soldering on electronic equipment; manufacturing of vehicles such as automobiles, vehicles and architecture These include painting, printing, and masking when giving up on civil engineering works.

  Adhesives for shoes include adhesives used for the adhesion between the shoe body (upper) and the sole (sole), heel, insole, decorative part, etc., and the adhesion between the outer sole and the midsole. A dressing may be mentioned.

  Examples of binding applications include wire harnesses, electric wires, cables, fibers, pipes, coils, windings, steel materials, ducts, plastic bags, foods, vegetables, and grooms. Packaging applications include heavy goods packaging, export packaging, cardboard box sealing, can seals, and the like. Office applications include general office work, sealing, book repair, drafting, and memos. Examples of label usage include price, product display, tag, POP, sticker, stripe, name plate, decoration, and advertisement.

  The labels include paper, processed paper (paper subjected to aluminum deposition, aluminum lamination, varnishing, resin processing, etc.), paper such as synthetic paper; cellophane, plastic material, cloth, wood and metal. The label which uses a film etc. as a base material is mentioned. Examples of the substrate include high-quality paper, art paper, cast paper, thermal paper, foil paper; polyethylene terephthalate film, OPP film, polylactic acid film, synthetic paper, synthetic paper thermal, overlamination film, and the like. Especially, the emulsion type adhesive agent obtained by this invention can be used suitably for the label using the base material which consists of a transparent material at the point which is excellent in transparency and a weather resistance. Moreover, since the emulsion type adhesive obtained by this invention has few discoloration with time, it can be used suitably for the thermal label which uses thermal paper or synthetic paper thermal as a base material.

  Examples of the adherend of the label include plastic products such as plastic bottles and foamed plastic cases; paper and cardboard products such as cardboard boxes; glass products such as glass bottles; metal products; and other inorganic material products such as ceramics. It is done.

The label made of a laminate including an adhesive layer made of an emulsion-type adhesive obtained in the present invention has excellent adhesion durability and maintains an adhesive state even when exposed to high temperature and high humidity conditions for a long time. However, there are no problems such as peeling.
Examples of decoration / display applications include danger display stickers, line tapes, wiring markings, phosphorescent tapes, and reflective sheets.

  Examples of adhesive film applications include polarizing films, polarizing plates, retardation films, viewing angle widening films, brightness enhancement films, antireflection films, antiglare films, color filters, light guide plates, diffusion films, prism sheets, and electromagnetic waves. An adhesive layer was formed on at least a part or all of one or both sides of a shield film, a near-infrared absorbing film, a functional composite optical film, an ITO bonding film, an impact resistance imparting film, a visibility improving film, etc. An optical film etc. are mentioned. Such an adhesive optical film includes a film in which an adhesive layer composed of an emulsion adhesive obtained in the present invention is formed on a protective film used for protecting the surface of the optical film. The adhesive type optical film is suitably used for various image display devices such as liquid crystal display devices, PDPs, organic EL display devices, electronic paper, game machines, and mobile terminals.

  Examples of electrical insulation applications include protective coating or insulation of coils, interlayer insulation such as motors and transformers, and the like. Electronic device holding and fixing applications include carrier tape, packaging, CRT fixing, splicing, rib reinforcement, and the like. Examples of semiconductor manufacturing include protection of silicone wafers. Examples of bonding applications include various adhesive fields, automobiles, trains, electrical equipment, printing plate fixing, architecture, nameplate fixing, general household use, rough surfaces, uneven surfaces, and adhesion to curved surfaces. Sealing applications include heat insulation, vibration proofing, waterproofing, moisture proofing, soundproofing or dustproof sealing. Examples of anticorrosion / waterproofing include gas, water pipe corrosion prevention, large-diameter pipe corrosion prevention, and civil engineering building corrosion prevention.

  For medical and hygiene applications, analgesic / anti-inflammatory agents (plasters, patches), cold patches, antipruritic patches, keratin softeners, and other transdermal absorption medicines; Various tape applications such as hemostatic bond, tape for human excrement disposal equipment (artificial anal fixation tape), suture tape, antibacterial tape, fixation taping, self-adhesive bandage, oral mucosa adhesive tape, sports tape, hair removal tape Cosmetic applications such as face packs, moisturizing sheets, and exfoliating packs; bonding applications of sanitary materials such as diapers and pet sheets; cooling sheets, thermal warmers, dustproofing, waterproofing, and pest capturing. As a sealing material application for electronic / electrical parts, a liquid crystal monitor, an organic EL (illumination application, display application, etc.), solar cell, and the like can be given.

  Further, the acrylic polymer aqueous dispersion obtained by the present invention includes paints, coating agents, mortar adhesion enhancers, mortar admixtures, caulking agents, binders, surface modifiers, cosmetics, in addition to the above emulsion type adhesives. It can be used for various purposes.

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples.
The acrylic block copolymers (I-1) to (I-3) used in the examples were synthesized by the methods of Synthesis Examples 1 to 3 below.

<< Synthesis Example 1 >> [Synthesis of Acrylic Block Copolymer (I-1)]
(1) After attaching a three-way cock to a 2 L three-necked flask and replacing the interior with nitrogen, 870 g of toluene and 40 g of 1,2-dimethoxyethane were added while stirring at room temperature, followed by isobutylbis (2,6- 80 g of a toluene solution containing 40 mmol of di-t-butyl-4-methylphenoxy) aluminum was added, and 3.5 g of a cyclohexane solution of sec-butyllithium containing 5.7 mmol of sec-butyllithium was further added.
(2) Subsequently, 22 g of methyl methacrylate was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature.
(3) Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., 290 g of n-butyl acrylate was added dropwise over 2 hours, and the mixture was stirred at −30 ° C. for 5 minutes after the completion of the addition.
(4) After adding 4 g of methanol to stop the polymerization reaction, the resulting reaction solution was poured into 15 kg of methanol to precipitate a liquid precipitate. Thereafter, the liquid precipitate was collected and dried to obtain 311 g of an acrylic block copolymer (I-1).

<< Synthesis Example 2 >> [Synthesis of Acrylic Block Copolymer (I-2)]
(1) After attaching a three-way cock to a 2 L three-necked flask and replacing the interior with nitrogen, 870 g of toluene and 40 g of 1,2-dimethoxyethane were added while stirring at room temperature, followed by isobutylbis (2,6- 80 g of a toluene solution containing 40 mmol of di-t-butyl-4-methylphenoxy) aluminum was added, and 2.0 g of a cyclohexane solution of sec-butyllithium containing 3.3 mmol of sec-butyllithium was further added.
(2) Subsequently, 32 g of methyl methacrylate was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature.
(3) Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., 240 g of n-butyl acrylate was added dropwise over 1 hour, and the mixture was stirred at −30 ° C. for 5 minutes after the completion of the addition.
(4) Further, 32 g of methyl methacrylate was added thereto, and the mixture was stirred overnight at room temperature.
(5) After adding 4 g of methanol to stop the polymerization reaction, the obtained reaction solution was poured into 15 kg of methanol to deposit a precipitate. Then, 303 g of acrylic block copolymers (I-2) were obtained by recovering the precipitate and drying it.

<< Synthesis Example 3 >> [Synthesis of Acrylic Block Copolymer (I-3)]
(1) After attaching a three-way cock to a 2 L three-necked flask and replacing the interior with nitrogen, 870 g of toluene and 40 g of 1,2-dimethoxyethane were added while stirring at room temperature, followed by isobutylbis (2,6- 80 g of a toluene solution containing 40 mmol of di-t-butyl-4-methylphenoxy) aluminum was added, and 1.5 g of a cyclohexane solution of sec-butyllithium containing 2.5 mmol of sec-butyllithium was further added.
(2) Subsequently, 32 g of methyl methacrylate was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature.
(3) Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., 240 g of n-butyl acrylate was added dropwise over 2 hours, and the mixture was stirred at −30 ° C. for 5 minutes after the completion of the addition.
(4) Further, 32 g of methyl methacrylate was added thereto, and the mixture was stirred overnight at room temperature.
(5) After adding 4 g of methanol to stop the polymerization reaction, the obtained reaction solution was poured into 15 kg of methanol to deposit a precipitate. Then, 303 g of acrylic block copolymers (I-3) were obtained by recovering the precipitate and drying it.

  Structure of acrylic block copolymers (I-1) to (I-3) obtained in Synthesis Examples 1 to 3, content of each polymer block, number average molecular weight (Mn), weight average molecular weight (Mw) Table 1 shows the molecular weight distribution (Mw / Mn).

  The number average molecular weight (Mn), the weight average molecular weight (Mw), the molecular weight distribution (Mw / Mn), and the content of each polymer block of the acrylic block copolymers (I-1) to (I-3) are as follows: It measured by the following method.

(1) Measurement of number average molecular weight (Mn), weight average molecular weight (Mw), molecular weight distribution (Mw / Mn) The molecular weight in terms of standard polystyrene was determined by gel permeation chromatography (hereinafter abbreviated as GPC).
・ Equipment: GPC equipment “HLC-8020” manufactured by Tosoh Corporation
・ Separation column: “TSKgel GMHXL”, “G4000HXL” and “G5000HXL” manufactured by Tosoh Corporation are connected in series. ・ Eluent: Tetrahydrofuran ・ Eluent flow rate: 1.0 ml / min ・ Column temperature: 40 ° C.
・ Detection method: Differential refractive index (RI)

(2) Measurement of content of each polymer block The content was determined by proton nuclear magnetic resonance spectroscopy ( ¹ H-NMR).
・ Apparatus: JEOL nuclear magnetic resonance apparatus “JNM-ECX400”
Solvent: deuterated chloroform In the ¹ H-NMR spectrum of the acrylic block copolymer, signals of 3.5 to 3.7 ppm and 3.8 to 4.1 ppm are respectively represented by ester groups of methyl methacrylate units ( —O—CH ₃ ) and the ester group (—O—CH ₂ —) of the n-butyl acrylate unit. The molar ratio of each monomer was determined from the ratio of these integral values, and this was converted into a mass ratio based on the molecular weight of the monomer unit to determine the content of each polymer block.

Example 1
85 g of n-butyl acrylate, 13 g of methyl methacrylate and 2 g of acrylic acid were mixed, and 5 g of the acrylic block copolymer (I-1) synthesized in Synthesis Example 1 was dissolved therein. Next, 8 g of ELEMINOL RS-3000 (component: methacryloyloxypolyoxypropylene sulfate sodium salt (anionic emulsifier having a nonionic hydrophilic group), 50% aqueous solution, manufactured by Sanyo Chemical Industries, Ltd.) as an emulsifier and ion-exchanged water 30 g was added and mixed with a homomixer to prepare a raw material emulsion containing an acrylic block copolymer and an acrylic monomer.

  Next, in a reactor equipped with a stirrer, a reflux condenser, a dropping funnel, a nitrogen inlet tube and a thermometer, 0.3 g of sodium hydrogen carbonate as a pH adjuster and 0.8 g of ammonium persulfate as a radical polymerization initiator were added. After dissolving in 110 g of ion-exchanged water, the inside of the reactor was purged with nitrogen. Then, after heating up to 75 degreeC, the whole amount of the said raw material emulsion was dripped over 3 hours from the dropping funnel, stirring, and the radical polymerization reaction was performed. The reaction was further driven at 85 ° C. for 2 hours, and then cooled to obtain an aqueous dispersion.

  This aqueous dispersion was applied to a polyester film having a thickness of 50 μm so that the film thickness after drying was 30 μm, and dried at 100 ° C. for 5 minutes to produce an adhesive film. The adhesive properties were evaluated. The results are shown in Table 2.

In addition, the solubility parameters of n-butyl acrylate, methyl methacrylate, and acrylic acid are 18.0 (J / cm ³ ) ^1/2 , 18 from Table 7 of VII / 688 to 694 of Non-Patent Document 2, respectively. 0 (J / cm ³ ) ^1/2 , 24.6 (J / cm ³ ) ^1/2 , and the specific gravity of n-butyl acrylate, methyl methacrylate, and acrylic acid is 0.900 (g / ml), respectively. 0.943 (g / ml) and 1.051 (g / ml). Therefore, SP (II) of the mixture of n-butyl acrylate / methyl methacrylate / acrylic acid = 85/13/2 is calculated from the above-mentioned formula (2), SP (II) = 18.13 (J / cm ³ ) Can be calculated as ^1/2 .

Example 2
An aqueous dispersion was obtained in the same manner as in Example 1 except that the acrylic block copolymer (I-1) was changed to the acrylic block copolymer (I-2). Further, the adhesive properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 3
An aqueous dispersion was obtained in the same manner as in Example 1 except that the acrylic block copolymer (I-1) was changed to the acrylic block copolymer (I-3). Further, the adhesive properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 4
An aqueous dispersion was obtained in the same manner as in Example 2 except that the mass of the acrylic block copolymer (I-2) was changed to 15 g. Further, the adhesive properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

<< Comparative Example 1 >>
An aqueous dispersion was obtained in the same manner as in Example 1 except that the mass of the acrylic block copolymer (I-1) was changed to 0.09 g. Further, the adhesive properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

<< Comparative Example 2 >>
When the mass of the acrylic block copolymer (I-1) was changed to 22 g and carried out in the same manner as in Example 1, aggregates were generated during radical polymerization, and a uniform aqueous dispersion could be obtained. There wasn't. For this reason, it was not possible to produce an adhesive film, and it was not possible to evaluate adhesive properties.

[Uniformity of water dispersion]
When the aqueous dispersion prepared in the above Example or Comparative Example is filtered with a 100 mesh metal filter, “○” indicates that the aggregate of the polymer collected by the filter is not observed. The case where it was seen was determined as “×”.

[Solid content of water dispersion]
2 g of the aqueous dispersion prepared in the above Example or Comparative Example is precisely weighed in an aluminum cup, and the mass of the solid content after drying at 105 ° C. for 2 hours is determined. Indicated.

[Peeling adhesive strength]
The adhesive film prepared in the above examples or comparative examples is cut into a tape shape having a width of 25 mm and a length of 200 mm, and this is cut on a stainless steel test plate as an adherend in an environment of 23 ° C. and 50% RH. Pasting was performed using a 2 kg rubber roller. Subsequently, after leaving for 24 hours in an environment of 23 ° C., 50% RH or 80 ° C., 95% RH, 180 ° at a speed of 5 mm / s in an environment of 23 ° C. and 50% RH in accordance with JIS Z0237. The peel strength was measured.

[Retention force]
The adhesive film prepared in the above-mentioned examples or comparative examples is cut into a tape shape having a width of 25 mm and a length of 100 mm, and this is applied to a stainless steel test plate as an adherend in an environment of 23 ° C. and 50% RH. Affixed with an adhesive area of width 25 mm × length 25 mm. Subsequently, the holding force was measured under the conditions of 60 ° C. and load of 1 kg in accordance with JIS Z0237. When the drop time was less than 120 minutes, the drop time was measured, and when it was 120 minutes or more, the shifted distance after 120 minutes was measured.

  The acrylic polymer aqueous dispersion obtained by the production method of the present invention is capable of forming a film having excellent durability under high temperature and high humidity as compared with the prior art. Emulsion adhesives, paints used in automobiles, railways, various vehicles, ships, storage containers, electrical machines, electronic equipment, precision equipment, display equipment, metal products, resin products, furniture, leather products, textile products, etc. It can be suitably used as a coating agent.

Claims (7)

  Acrylic block copolymer (I) 0.1 having at least one polymer block (A) composed of alkyl methacrylate units and at least one polymer block (B) composed of alkyl acrylate units. ~ 20 parts by mass is dissolved in 100 parts by mass of a monomer component containing at least one acrylic monomer (II) selected from (meth) acrylic acid esters and (meth) acrylic acid, and the resulting solution is submerged in water. A method for producing an aqueous dispersion of an acrylic polymer in which a monomer component containing an acrylic monomer (II) is radically polymerized in a dispersed state.   The acrylic block copolymer (I) is a diblock copolymer represented by the formula: (A)-(B) and a triblock represented by the formula: (A)-(B)-(A). Block copolymer [wherein (A) represents a polymer block (A) composed of alkyl methacrylate units, (B) represents a polymer block (B) composed of alkyl acrylate units, and − represents The bond of each polymer block is shown. The method for producing an aqueous dispersion of an acrylic polymer according to claim 1, which is at least one acrylic block copolymer selected from the group consisting of:   The method for producing an aqueous dispersion of an acrylic polymer according to claim 1 or 2, wherein the acrylic block copolymer (I) has a molecular weight distribution of 1.0 to 1.5.   The method for producing an aqueous dispersion of an acrylic polymer according to any one of claims 1 to 3, wherein the acrylic block copolymer (I) has a number average molecular weight of less than 100,000. The absolute value of the difference between the solubility parameter SP (B) of the polymer block (B) of the acrylic block copolymer (I) and the solubility parameter SP (II) of the acrylic monomer (II) is 0.4 ( J / cm ³ ) ^1/2 or less The method for producing an aqueous dispersion of an acrylic polymer according to any one of claims 1 to 4.   The aqueous dispersion of the acrylic polymer manufactured with the manufacturing method of any one of the said Claims 1-5.   The emulsion type adhesive which consists of the aqueous dispersion of the acrylic polymer manufactured with the said manufacturing method of any one of the said Claims 1-5.