JP2008291130A - Anionic aqueous dispersion of acrylic block copolymer and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous dispersion of an acrylic block copolymer giving little load on the environment and human body in processing, having small particle diameter and excellent storage stability, free from discoloration and surfactant bleed-out troubles in the case of drying the aqueous dispersion to form a solid, and having excellent heat-resistance, oil resistance, weather resistance, transparency, softness, adhesiveness to substrates, etc. , and to provide a method for producing the dispersion, and a formed article or an adhesive obtained from the anionic aqueous dispersion. <P>SOLUTION: The invention provides an anionic aqueous dispersion of an acrylic block copolymer produced by emulsifying and dispersing an acrylic block copolymer in the presence of 1-15 pts.wt. of an anionic surfactant based on 100 pts.wt. of the acrylic block copolymer, a method for producing the dispersion, and a formed article or an adhesive obtained from the anionic aqueous dispersion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an anionic aqueous dispersion of an acrylic block copolymer, a method for producing the same, and a molded product or an adhesive obtained from the anionic aqueous dispersion of an acrylic block copolymer.

  Thermoplastic elastomers have the characteristics that they can be machine-molded in the same way as plastics while being the same elastic body as rubber, and various materials are used in a wide range of industrial fields. Among these, styrenic thermoplastic elastomers such as SBS (polystyrene-polybutadiene-polystyrene block copolymer) in which butadiene is introduced as a soft segment have been produced for a long time. However, these styrenic thermoplastic elastomers have problems such as inferior heat resistance and weather resistance because they have unsaturated bonds in the block portion of polybutadiene.

  As this improved product, SEBS (polystyrene-poly (ethylene-butadiene) -polystyrene block copolymer) type styrenic thermoplastic elastomers with improved heat resistance and weather resistance by hydrogenating unsaturated bonds were produced. However, since a small amount of unsaturated bonds remain, further improvement may be required. Further, since these SBS and SEBS are composed of low-polarity molecules, their use has been limited to parts that require oil resistance and parts that require adhesion and adhesion to a substrate having polarity.

  On the other hand, a thermoplastic elastomer such as an acrylic block copolymer having methyl methacrylate as a hard segment and butyl acrylate as a soft segment has been proposed in recent years. Acrylic block copolymer has no unsaturated bond, so it not only has excellent heat resistance and weather resistance, but also has (meth) acrylic acid ester polymer as the main chain skeleton, so it is oil resistant and flexible. Development is progressing as a material having characteristics such as excellent properties, adhesion to a substrate, adhesiveness, and transparency (see Patent Documents 1 and 2).

Many of these acrylic block copolymers are used by mechanical molding such as extrusion molding and injection molding, but when used for coating agents and adhesives on various materials, they are in a solution state dissolved in an organic solvent. There were problems with the environment due to vaporization of the organic solvent contained and problems with the human body during work.
WO 2004/013192 JP 09-059583 A

  The object of the present invention is to reduce the load on the environment and the human body during processing, have a small particle size and excellent storage stability, and when the aqueous dispersion is dried to be a solid, there is no coloring or bleed out of the surfactant. Furthermore, an aqueous dispersion of an acrylic block copolymer having excellent heat resistance, oil resistance, weather resistance, transparency, flexibility, adhesion to a substrate, and the like, a method for producing the same, and an acrylic block copolymer The present invention relates to a molded product or a pressure-sensitive adhesive obtained from an anionic aqueous dispersion of

As a result of intensive studies to solve the above problems, the present inventors can solve the above problems by emulsifying and dispersing an acrylic block copolymer in water in the presence of an anionic surfactant. I found out. That is, the present invention
(I) An acrylic block copolymer (A) comprising a methacrylic polymer block (a) and an acrylic polymer block (b) is added to 100 parts by weight of the acrylic block copolymer (A). An anionic aqueous dispersion of an acrylic block copolymer, which is emulsified and dispersed in water in the presence of 1 to 15 parts by weight of an anionic surfactant (B);
(II). At least one monomer selected from the group consisting of acrylic polymer block (b) consisting of acrylate-n-butyl, ethyl acrylate, and 2-methoxyethyl acrylate 50-100 weight And 50 to 0% by weight of acrylic acid ester and / or vinyl monomer other than acrylic acid-n-butyl, ethyl acrylate and acrylic acid-2-methoxyethyl copolymerizable therewith. An anionic aqueous dispersion of an acrylic block copolymer as described in (I),
(III). The methacrylic polymer block (a) comprises 50 to 100% by weight of methyl methacrylate and 0 to 50% by weight of a vinyl monomer copolymerizable therewith. An anionic aqueous dispersion of an acrylic block copolymer of
(IV). The acrylic block copolymer (A) has at least one functional group selected from the group consisting of an acid anhydride group, a carboxyl group, a hydroxyl group, and an epoxy group in one molecule. An anionic aqueous dispersion of an acrylic block copolymer according to any one of (I) to (III),
(V). The anionic surfactant (B) is at least one selected from the group consisting of dialkyl sulfosuccinates, aliphatic polyoxyalkylene ether sulfates, fatty acid salts and alkylbenzene sulfonates (I) to An anionic aqueous dispersion of the acrylic block copolymer according to any one of (IV),
(VI). Any of (I) to (V), wherein the acrylic block copolymer (A) in the anionic aqueous dispersion is in the form of particles having an average particle size of 0.1 to 3 μm. An anionic aqueous dispersion of the acrylic block copolymer according to item 1,
(VII) A molded article of an acrylic block copolymer obtained from the anionic aqueous dispersion of the acrylic block copolymer (A) according to any one of (I) to (VI),
(VIII). An acrylic block copolymer pressure-sensitive adhesive obtained from the anionic aqueous dispersion of the acrylic block copolymer (A) according to any one of (I) to (VII),
(IX) Acrylic block copolymer (A) dissolved in an organic solvent and an anionic surfactant (B) dissolved in water are mixed and emulsified, and then the organic solvent is distilled off. A method for producing an anionic aqueous dispersion of an acrylic block copolymer according to any one of (I) to (VIII),
About.

  The anionic aqueous dispersion of the acrylic block copolymer of the present invention has less burden on the environment and human body during processing, there is no coloring or bleed out of the surfactant, and further, heat resistance, oil resistance, weather resistance Further, it is possible to obtain a molded article or a pressure-sensitive adhesive using an acrylic block copolymer that is excellent in transparency, flexibility, adhesion to a substrate, and the like.

  Hereinafter, each component of the present invention will be described in detail.

<Acrylic block copolymer (A)>
The structure of the acrylic block copolymer (A) of the present invention is not particularly limited, and may be a linear block copolymer, a branched (star) block copolymer, or a mixture thereof. The structure of such a block copolymer may be appropriately selected according to the required physical properties of the acrylic block copolymer (A). However, from the viewpoint of cost and ease of polymerization, the linear block copolymer is selected. Polymers are preferred. The linear block copolymer may have any structure (arrangement). From the viewpoint of the physical properties of the linear block copolymer or the physical properties of the composition, the methacrylic polymer block (a ) and a, when the acrylic polymer block (b) is expressed as b, _{(a-b) n} type, b- _{(a-b) n} type and _(a-b) n -a-type (n is 1 It is preferably at least one acrylic block copolymer selected from the group consisting of the above integers (for example, an integer of 1 to 3). Among these, an ab type diblock copolymer, an abb type triblock copolymer, or a mixture thereof is preferable from the viewpoint of easy handling during processing and physical properties of the composition.

  The molecular weight of the acrylic block copolymer (A) is not particularly limited, and may be determined from the molecular weights required for the methacrylic polymer block (a) and the acrylic polymer block (b). If the molecular weight is small, sufficient mechanical properties as an elastomer may not be exhibited. Conversely, if the molecular weight is larger than necessary, the processing properties may deteriorate. From such a viewpoint, the molecular weight of the acrylic block copolymer (A) is preferably 30,000 to 200,000 in terms of number average molecular weight, more preferably 35,000 to 150,000, and still more preferably 50,000 to 50,000. 130,000.

  The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography of the acrylic block copolymer (A) is not particularly limited, but is 1.8 or less. It is preferable that it is 1.5 or less. When the Mw / Mn exceeds 1.8, the uniformity of the acrylic block copolymer deteriorates. When used as a molded product, mechanical properties such as mechanical strength and elongation decrease, and when used as an adhesive, it melts. And retention at high temperatures may be reduced.

  The composition ratio of the methacrylic polymer block (a) and the acrylic polymer block (b) constituting the acrylic block copolymer (A) is 5 to 90% by weight of the methacrylic polymer block (a). The acrylic polymer block (b) is preferably set to 95 to 10% by weight. When used as a molded product, the methacrylic polymer block (a) is 10 to 60% by weight and the acrylic polymer block (b) is 90 to 90% from the viewpoint of maintaining the shape during molding and elasticity as an elastomer. More preferably, it is set to 40% by weight, more preferably 15 to 50% by weight of the methacrylic polymer block (a) and 85 to 50% by weight of the acrylic polymer block (b). When the proportion of the methacrylic polymer block (a) is less than 5% by weight, the shape tends to be difficult to be maintained during molding. When the proportion of the acrylic polymer block (b) is less than 10% by weight, There exists a tendency for the elasticity and softness | flexibility of this, and the meltability at the time of shaping | molding to fall.

  When used as an adhesive, the methacrylic polymer block (a) is 5 to 40% by weight and the acrylic polymer block (b) is 95 to 60% by weight from the viewpoint of the adhesive strength and holding power of the adhesive. More preferably, the methacrylic polymer block (a) is 5 to 30% by weight, and the acrylic polymer block (b) is 95 to 70% by weight. When the proportion of the methacrylic polymer block (a) is less than 5% by weight, the holding power at high temperature tends to decrease, and when the proportion of the acrylic polymer block (b) is less than 60% by weight, the adhesive There is a tendency to lose power.

  From the viewpoint of the hardness of the acrylic block copolymer, the hardness is low when the proportion of the methacrylic polymer block (a) is small, and the hardness is high when the proportion of the acrylic polymer block (b) is small. The composition is appropriately set according to the required hardness of the acrylic block copolymer. Further, from the viewpoint of processing, when the proportion of (a) is small, the viscosity tends to be low, and when the proportion of (b) is small, the viscosity tends to be high, and the composition is appropriately set according to the required processing characteristics. .

The relationship between the glass transition temperatures of the methacrylic polymer block (a) and the acrylic polymer block (b) constituting the acrylic block copolymer (A) gives elastomer properties and rubber elasticity in the case of a molded product. In the case of a pressure-sensitive adhesive, it is preferable that the glass transition temperature of one of the polymer blocks is higher than the glass transition temperature of the other polymer block in terms of imparting adhesive strength and holding power. The glass transition temperature of each block (Tg _a is the glass transition temperature of the methacrylic polymer block (a), and Tg _b is the glass transition temperature of the acrylic polymer block (b)). It is more preferable to satisfy the relationship of the following formula.
Tg _a > Tg _b

The glass transition temperature (Tg) of the polymer (the methacrylic polymer block (a) and the acrylic polymer block (b)) is set according to the following Fox formula. This can be done by setting.
_{1 / Tg = (W 1 /} Tg 1) + (W 2 / Tg 2) + ... + (W m / Tg m)
W ₁ + W ₂ + ... + W _m = 1
In the formula, Tg represents the glass transition temperature of the polymer portion, and Tg ₁ , Tg ₂ ,..., Tg _m represent the glass transition temperature of each polymerization monomer. W ₁ , W ₂ ,..., W _m represent the weight ratio of each polymerization monomer.

  As the glass transition temperature of each polymerization monomer in the Fox formula, for example, a value described in Polymer Handbook Third Edition (Wiley-Interscience 1989) may be used.

  The glass transition temperature can be measured by DSC (differential scanning calorimetry) or tan δ peak of dynamic viscoelasticity, but the polarities of the methacrylic polymer block (a) and the acrylic polymer block (b). If they are too close, or if the number of monomer chains in the block is too small, the measured values may deviate from the calculation formula based on the Fox equation.

<Methacrylic polymer block (a)>
The methacrylic polymer block (a) is a block formed by polymerizing a monomer having a methacrylic acid ester as a main component. The methacrylic acid ester is 50 to 100% by weight and a vinyl copolymer copolymerizable therewith. It is preferably composed of 0 to 50% by weight of monomer. When the proportion of the methacrylic acid ester is less than 50% by weight, the weather resistance, transparency, etc., which are characteristics of the methacrylic acid ester, may be impaired.

  Examples of the methacrylic acid ester constituting the methacrylic polymer block (a) include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, N-pentyl methacrylate, n-hexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, Methacrylic acid aliphatic hydrocarbons (eg, alkyl having 1 to 18 carbon atoms) such as stearyl methacrylate; Methacrylic acid alicyclic hydrocarbon esters such as cyclohexyl methacrylate and isobornyl methacrylate; Benzyl methacrylate Etc. Acid aralkyl esters; methacrylic aromatic hydrocarbon esters such as phenyl methacrylate and toluyl methacrylate; methacrylic acid such as 2-methoxyethyl methacrylate and 3-methoxybutyl methacrylate and etheric oxygen Esters with functional group-containing alcohols; trifluoromethyl methacrylate, trifluoromethyl methyl methacrylate, 2-trifluoromethyl ethyl methacrylate, 2-trifluoroethyl methacrylate, 2-perfluoroethyl methacrylate Ethyl, 2-perfluoroethyl-2-perfluorobutyl ethyl methacrylate, 2-perfluoroethyl methacrylate, perfluoromethyl methacrylate, diperfluoromethyl methyl methacrylate, 2-perfluoro methacrylate Fluoroalkyl methacrylates such as romethyl-2-perfluoroethylmethyl, 2-perfluorohexylethyl methacrylate, 2-perfluorodecylethyl methacrylate, 2-perfluorohexadecylethyl methacrylate, etc. can give. These can be used alone or in combination of two or more. Among these, methyl methacrylate is preferable in terms of processability, cost, and availability.

  Examples of vinyl monomers copolymerizable with the methacrylic acid ester constituting the methacrylic polymer block (a) include, for example, acrylic acid esters, aromatic alkenyl compounds, vinyl cyanide compounds, conjugated diene compounds, Examples thereof include halogen-containing unsaturated compounds, vinyl ester compounds, maleimide compounds, and the like.

  Examples of the acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, N-octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, and the like, acrylate aliphatic hydrocarbon (eg, alkyl having 1 to 18 carbon atoms) ester; cyclohexyl acrylate Acrylic acid cycloaliphatic hydrocarbon esters such as isobornyl acrylate; Acrylic aromatic hydrocarbon esters such as phenyl acrylate and toluyl acrylate; Aralkyl acrylates such as benzyl acrylate; 2-methoxyethyl acrylate , An ester of acrylic acid such as 3-methoxybutyl acrylate and a functional group-containing alcohol having etheric oxygen; trifluoromethyl methyl acrylate, 2-trifluoromethyl ethyl acrylate, 2-perfluoroethyl ethyl acrylate, 2-perfluoroethyl-2-perfluorobutylethyl acrylate, 2-perfluoroethyl acrylate, perfluoromethyl acrylate, diperfluoromethylmethyl acrylate, 2-perfluoromethyl-2-perfluoroethyl acrylate Examples thereof include fluorinated alkyl acrylates such as methyl, 2-perfluorohexylethyl acrylate, 2-perfluorodecylethyl acrylate, and 2-perfluorohexadecylethyl acrylate.

  Examples of the aromatic alkenyl compound include styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, and the like.

  Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.

  Examples of the conjugated diene compound include butadiene and isoprene.

  Examples of the halogen-containing unsaturated compound include vinyl chloride, vinylidene chloride, perfluoroethylene, perfluoropropylene, and vinylidene fluoride.

  Examples of the vinyl ester compound include vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate, and the like.

  Examples of the maleimide compound include maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide and the like.

  These compounds can be used alone or in combination of two or more. These vinyl monomers are preferably selected from the viewpoints of adjusting the glass transition temperature required for the methacrylic polymer block (a) and compatibility with the acrylic block (b).

When using as a molded body or a pressure-sensitive adhesive, the cohesion and the glass transition temperature Tg _a of the methacrylic polymer block (a) is increased, there is a tendency that heat resistance and holding power is increased.

  The glass transition temperature of the methacrylic polymer block (a) is preferably from 25 to 200 ° C., more preferably from the viewpoint of thermal deformation (heat resistance and holding power) and moldability of the acrylic block copolymer. Is 50 to 150 ° C, more preferably 70 to 120 ° C. When the glass transition temperature is higher than 200 ° C., the moldability tends to be lowered, and when it is lower than 50 ° C., the heat deformability tends to be deteriorated.

  From this point, it is desirable that the methacrylic polymer block (a) is mainly composed of methyl methacrylate, and ethyl acrylate is used for the purpose of adjusting the glass transition temperature of the methacrylic polymer block (a). It is preferable to polymerize at least one monomer selected from the group consisting of acrylic acid-n-butyl and acrylic acid-2-methoxyethyl. Of these, ethyl acrylate is particularly preferable from the viewpoint of compatibility with methyl methacrylate.

Tg _a configuration of the methacrylic polymer block (a) in accordance with said Fox equation, can be performed by setting the weight ratio of the monomers of each polymer portion.

<Acrylic polymer block (b)>
The acrylic polymer block (b) is a block obtained by polymerizing a monomer having an acrylic ester as a main component, and includes 50 to 100% by weight of the acrylic ester and a vinyl monomer copolymerizable therewith. It is preferably composed of 0 to 50% by weight. If the proportion of the acrylic ester is less than 50% by weight, the physical properties of the composition, particularly flexibility and oil resistance, which are characteristic when the acrylic ester is used, may be impaired.

  Examples of the acrylate ester constituting the acrylic polymer block (b) include the same monomers as the acrylate ester exemplified as the monomer constituting the methacrylic polymer block (a). it can.

  These can be used alone or in combination of two or more. Among these, acrylic acid-n-butyl is preferable in terms of balance between flexibility, rubber elasticity, low temperature characteristics, and cost. If oil resistance and mechanical properties are required, ethyl acrylate is preferred. In addition, when it is necessary to impart low temperature characteristics and oil resistance and to improve the surface tackiness of the resin, 2-methoxyethyl acrylate is preferred. Further, when a balance between oil resistance and low-temperature characteristics is required, it is preferable to use a combination of ethyl acrylate, acrylic acid-n-butyl and acrylic acid-2-methoxyethyl. In the case of imparting adhesive properties, it is preferable to use acrylate-n-butyl and / or -2-ethylhexyl acrylate. Furthermore, at least one kind selected from the group consisting of acrylic acid-n-butyl, ethyl acrylate, 2-methoxyethyl acrylate, and 2-ethylhexyl acrylate, in terms of cost and physical property balance More preferably, it consists of 50 to 100% by weight of the body and 50 to 0% by weight of other acrylic ester and / or other vinyl monomer copolymerizable therewith.

  Examples of vinyl monomers copolymerizable with the acrylic ester constituting the acrylic polymer block (b) include methacrylic ester, aromatic alkenyl compound, vinyl cyanide compound, conjugated diene compound, halogen, and the like. -Containing unsaturated compounds, silicon-containing unsaturated compounds, unsaturated carboxylic acid compounds, unsaturated dicarboxylic acid compounds, vinyl ester compounds, maleimide compounds, etc., and specific examples thereof include methacrylic polymer blocks The thing similar to the said thing used for (a) can be mention | raise | lifted.

  These vinyl monomers can be used alone or in combination of two or more. These vinyl monomers are appropriately selected in consideration of the balance of the glass transition temperature and oil resistance required for the acrylic polymer block (b), compatibility with the methacrylic polymer block (a), and the like. Choose the preferred one. For example, acrylonitrile may be copolymerized for the purpose of improving the oil resistance of the composition.

  The glass transition temperature of the acrylic polymer block (b) is preferably 25 ° C. or lower, more preferably 0 ° C. or lower, from the viewpoints of the flexibility, rubber elasticity, and adhesive properties of the acrylic block copolymer. More preferably, it is −20 ° C. or lower. When the glass transition temperature of the acrylic polymer block (b) is higher than the temperature of the environment in which the elastomer composition is used, flexibility, rubber elasticity, and adhesive properties are hardly exhibited.

The Tg _b of the acrylic polymer block (b) can be set by setting the weight ratio of the monomers in each polymer portion according to the Fox formula.

  In the present invention, if necessary, the acrylic block copolymer (A) has at least one functional group selected from an acid anhydride group, a carboxyl group, a hydroxyl group, and an epoxy group in at least one molecule. You may have more than one. By introducing a functional group, there are cases where heat resistance, holding power, and even adhesiveness can be imparted to the molded article and pressure-sensitive adhesive obtained.

  In the present invention, the functional group is an acid anhydride group, a carboxyl group, a hydroxyl group, from the viewpoints of heat resistance, holding power, adhesion, ease of introduction into the acrylic block copolymer (A), cost, and the like. It is preferably at least one selected from epoxy groups.

  These functional groups are introduced into the acrylic block copolymer (A) in a form in which the functional group is protected with an appropriate protective group, or in the form of a precursor of the functional group, and then a known chemical reaction is performed. Functional groups can also be generated.

  These functional groups can be used in combination of two or more, but when two or more types are used in combination, it is preferable to select functional groups that do not react with each other.

  The functional group may be contained only in one of the methacrylic polymer block (a) and the acrylic polymer block (b), or may be contained in both blocks. Reaction point of the block copolymer (A), cohesive force of the blocks constituting the acrylic block copolymer (A) (methacrylic polymer block (a) and acrylic polymer block (b)) Depending on the purpose, such as the glass transition temperature and the required physical properties of the acrylic block copolymer (A), the conditions for introducing functional groups can be used appropriately.

  For example, in terms of improving heat resistance and heat decomposability of the acrylic block copolymer (A), a functional group may be introduced into the methacrylic polymer block (a), and the acrylic block copolymer (A). A functional group may be introduced into the acrylic polymer block (b) from the viewpoint of imparting oil resistance, compression set characteristics, and adhesive properties. Although not particularly limited, either the methacrylic polymer block (a) or the acrylic polymer block (b) in terms of control of reaction points, heat resistance, rubber elasticity, mechanical strength, flexibility, and the like. It is preferable to introduce a functional group into the block.

  The content of the functional group includes the cohesive force of the functional group, the structure and composition of the acrylic block copolymer (A), the number of blocks constituting the acrylic block copolymer (A), the glass transition temperature, and It varies depending on the site and manner in which the functional group is contained. Therefore, what is necessary is just to set as needed, Preferably it is 1.0 or more per molecule | numerator of an acryl-type block copolymer (A), More preferably, it is 2.0 or more. When the number is less than 1.0, the acrylic block copolymer (A) tends to be insufficient in improving heat resistance and imparting adhesive properties.

  When the functional group is introduced into the methacrylic polymer block (a), it is preferably introduced within a range where the moldability of the acrylic block copolymer (A) is not lowered.

Specifically 200 ° C. The glass transition temperature Tg _a of the methacrylic polymer block after introduction of the functional group (a) or less, more preferably 0.99 ° C. or less, more preferably introduced within a range such that 130 ° C. or less It is preferable to do.

When the functional group is introduced into the acrylic polymer block (b), it is preferably introduced within a range in which the flexibility, rubber elasticity, and low temperature characteristics of the acrylic block copolymer (A) are not deteriorated. When the cohesive force of the acrylic polymer block (b) and the glass transition temperature Tg _b are improved by the introduction of the functional group, the flexibility, rubber elasticity, and low temperature characteristics tend to deteriorate. Specifically, the acrylic polymer block (b) after introduction of the functional group is introduced in such a range that the glass transition temperature Tg _b is 25 ° C. or lower, more preferably 0 ° C. or lower, and further preferably −20 ° C. or lower. It is preferable to do.

  Hereinafter, hydroxyl groups, carboxyl groups, acid anhydride groups, and epoxy groups will be described as preferred examples of functional groups.

<Hydroxyl group>
The hydroxyl group may be introduced into the main chain of the acrylic block copolymer (A) or may be introduced into the side chain, but from the ease of introduction into the acrylic block copolymer (A). It is preferably introduced into the side chain.

  The method for introducing the hydroxyl group into the block copolymer (A) is not particularly limited, but a (meth) acrylic monomer containing a hydroxyl group may be directly polymerized during the polymerization of the block copolymer (A). After the polymer (A) is polymerized, the diol component may be introduced using an esterification reaction or a transesterification reaction. From the viewpoint of easy reaction, it is preferable to directly polymerize a (meth) acrylic monomer containing a hydroxyl group at the time of polymerization of the block copolymer (A). Here, in this application, (meth) acryl means acryl or methacryl.

  Specific (meth) acrylic monomers include (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, (meth) acrylic acid-3-hydroxypropyl, (meth) acrylic acid- 4-hydroxybutyl, Blemmer E series (Nippon Yushi Co., Ltd.), Blemmer PE series (Nippon Yushi Co., Ltd.), Blemmer AE series (Nippon Yushi Co., Ltd.), Blemmer P (Nippon Yushi Co., Ltd.), Blemmer PP Series (Nippon Yushi Co., Ltd.), Blemmer AP Series (Nippon Yushi Co., Ltd.), Blemmer PEP Series (Nippon Yushi Co., Ltd.), Blemmer AEP Series (Nippon Yushi Co., Ltd.), Blemmer PET Series (Nippon Yushi Co., Ltd. )), Blemmer AET series (Nippon Yushi Co., Ltd.), Blemmer PPT series (Nippon Yushi ( )), Such as Blenmer APT series (NOF Corporation) are exemplified.

  These compounds can be used alone or in combination of two or more. Among these, (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, and (meth) acrylic acid-4-hydroxybutyl are easily polymerized and easily available. Is preferable. Although not particularly limited, when it is contained in the methacrylic polymer block (a), it is preferably a hydroxyl group-containing methacrylic acid ester derivative, and when it is contained in the acrylic polymer block (b), it is a hydroxyl group-containing acrylic acid. An ester derivative is preferred. When it is a hydroxyl group-containing acrylate derivative when included in the methacrylic polymer block (a), or when it is a hydroxyl group-containing methacrylic ester derivative when included in the acrylic polymer block (b) The block copolymer (A) has a complicated polymerization operation, and the difference in glass transition temperature between the methacrylic polymer block (a) and the acrylic polymer block (b) becomes small, and the acrylic block copolymer. The rubber elasticity and flexibility of (A) tend to decrease.

<Carboxyl group>
The carboxyl group may be introduced into the main chain of the acrylic block copolymer (A) or may be introduced into the side chain, but is easy to introduce into the acrylic block copolymer (A). Therefore, it is preferably introduced into the main chain.

  When the monomer having a carboxyl group does not deactivate the catalyst under the polymerization conditions, the introduction of the carboxyl group is preferably introduced by direct polymerization. In the case of deactivation, it is preferable to introduce a carboxyl group by functional group conversion.

  In the method of introducing a carboxyl group by functional group conversion, the carboxyl group is introduced into the acrylic block copolymer in a form protected with an appropriate protective group or in the form of a functional group that is a precursor of the carboxyl group. The functional group can be generated by a known chemical reaction. By this method, a carboxyl group can be introduced.

  For example, an acrylic block copolymer containing a monomer having a functional group that becomes a precursor of a carboxyl group such as t-butyl (meth) acrylate and trimethylsilyl (meth) acrylate is synthesized and hydrolyzed. Alternatively, a method of generating a carboxyl group by a known chemical reaction such as acid decomposition (JP-A-10-298248, JP-A-2001-234146), for example, (meth) acrylic acid-t-butyl, (meth) acrylic A method of synthesizing and melt-kneading an acrylic block copolymer containing unit amounts such as isopropyl acid, α, α-dimethylbenzyl (meth) acrylate, and α-methylbenzyl (meth) acrylate (JP 2006-104419 A) No.).

<Acid anhydride group>
The acid anhydride group is not particularly limited, but may be introduced into the main chain of the acrylic block copolymer (A) or may be introduced into the side chain. The acid anhydride group is an anhydride group of a carboxyl group, and is preferably introduced into the main chain from the viewpoint of easy introduction into the acrylic block copolymer (A). It is preferably introduced in the form represented by General formula (1):

(In the formula, R ¹ is hydrogen or a methyl group and may be the same or different. N is an integer of 0 to 3, m is an integer of 0 or 1) n in the general formula (1) is 0 to 3 And is preferably 0 or 1, more preferably 1. When n is 4 or more, polymerization tends to be complicated, and cyclization of the acid anhydride group tends to be difficult.

  Regarding the method of introducing an acid anhydride group, when the monomer having an acid anhydride group does not deactivate the catalyst under the polymerization conditions, it is preferably introduced by direct polymerization. In the case where the monomer possessed deactivates the catalyst during polymerization, a method of introducing an acid anhydride group by functional group conversion is preferred. Although not particularly limited, a method of introducing into an acrylic block copolymer as a precursor of an acid anhydride group, such as (meth) acrylic acid-t-butyl, and then melt-kneading (WO 2004/013192) ) Can be introduced.

<Epoxy group>
The epoxy group is not particularly limited as long as it is an organic group containing an epoxy ring. For example, 1,2-epoxyethyl group, 2,3-epoxypropyl group (that is, glycidyl group), 2,3-epoxy-2- Examples thereof include aliphatic hydrocarbon (eg, alkyl) groups having an epoxy ring such as methylpropyl group; alicyclic hydrocarbon groups having an epoxy ring such as 3,4-epoxycyclohexyl group. These may be selected from the reactivity, reaction rate, availability, cost, etc. as necessary. Although it does not restrict | limit in particular, A glycidyl group is preferable in these in view of availability.

  Regarding the method for introducing an epoxy group, it is preferable to introduce a monomer having an epoxy group by direct polymerization. Examples of the monomer having an epoxy group include glycidyl (meth) acrylate, 2,3-epoxy-2-methylpropyl (meth) acrylate, and (3,4-epoxycyclohexyl) methyl (meth) acrylate ( Examples thereof include esters of (meth) acrylic acid and an organic group-containing alcohol containing an epoxy ring; and epoxy group-containing unsaturated compounds such as 4-vinyl-1-cyclohexene 1 and 2 epoxides. These may be selected from reactivity, reaction rate, availability, cost, etc., if necessary, and are not particularly limited, but among these, glycidyl (meth) acrylate is easy to obtain. Is preferred.

<Method for producing acrylic block copolymer (A)>
The method for producing the acrylic block copolymer (A) is not particularly limited, but it is preferable to use a controlled polymerization method using an initiator. Examples of the controlled polymerization method include a living anion polymerization method, a radical polymerization method using a chain transfer agent, and a recently developed living radical polymerization method. Of these, the living radical polymerization method is preferred from the viewpoint of controlling the molecular weight and structure of the acrylic block copolymer.

  The living radical polymerization method is a radical polymerization method in which the activity at the polymerization terminal is maintained without being lost. In the narrow sense, the living polymerization method refers to a polymerization method in which the terminal always has activity, but in general, the pseudo-living polymerization method in which the terminal inactivated and the terminal are in an equilibrium state. Is also included. The definition here is also the latter. The living radical polymerization method has been actively researched by various groups in recent years.

  Examples thereof include those using a chain transfer agent such as polysulfide, cobalt porphyrin complex (J. Am. Chem. Soc., 1994, 116, 7943), Those using radical scavengers such as nitroxide compounds (Macromolecules, 1994, 27, 7228), atom transfer radical polymerization method using organic halide as initiator and transition metal complex as catalyst (Atom Transfer Radical Polymerization: ATRP). In the present invention, any of these methods is not particularly limited, but the atom transfer radical polymerization method is preferred from the viewpoint of easy control.

  Specific examples of the atom transfer radical polymerization method include the method described in JP-A-2004-107447.

<Anionic surfactant (B)>
In the present invention, an anionic surfactant is essential in order to emulsify and disperse the acrylic block copolymer (A) in water.

  The surfactant used in the present invention is not particularly limited as long as it is an anionic surfactant. For example, aliphatic polyoxyalkylene ether sulfate, polyoxyalkylene alkylphenyl ether sulfate, alkylbenzene sulfonate, Alkyl naphthalene sulfonate, alkyl diphenyl sulfonate, α-olefin sulfonate, alkyl sulfate ester salt, naphthalene sulfonate formalin condensate, dialkyl sulfosuccinate, polyoxyethylene alkyl ether acetate, rosinate and fatty acid Examples thereof include fatty acid salts such as sodium and fatty acid potassium. These may be used alone or in admixture of two or more.

Among these anionic surfactants, at least one selected from the group consisting of dialkyl sulfosuccinates, aliphatic polyoxyalkylene ether sulfates, fatty acid salts and alkylbenzene sulfonates is preferable. .
The dialkylsulfosuccinate has the following general formula [I]
YO ₃ SCH (CH ₂ COOR ¹ ) COOR ² [I]
(In the formula, Y represents a sodium atom, a potassium atom, an amino group or an ammonia group, and R ¹ and R ² may be the same or different and each represents an alkyl group having 5 to 12 carbon atoms or a phenyl group). It is a compound represented.

  Specific examples of the dialkylsulfosuccinate include dioctylsulfosuccinate, diethylhexylsulfosuccinate, dialkylphenylsulfosuccinate, didodecylsulfosuccinate and the like. Among them, particularly preferable results are obtained when dioctyl sulfosuccinate is used.

The aliphatic polyoxyalkylene ether sulfate has the general formula [II]
R ³ (AO) _n SO ₃ Y [II]
(In the formula, Y represents a sodium atom, a potassium atom, an amino group or an ammonia group, R ³ represents an alkyl group having 5 to 24 carbon atoms or an alkenyl group having 5 to 24 carbon atoms, and n represents an added mole) the .AO represents an integer of 2 to 50 indicate the _{number, - (- C 2 H 4} O-) n1 - (- C 3 H 6 O-) n2 - (n1 = 0~50, n2 = 0~50, However, an n1 + n2 = 2 to 50, when n1 ≠ 0 and _{n2 ≠ 0, -C 2 H 4} O- and _-C 3 order of the _H 6 O-regardless, in block or at random.) the It is a compound represented by.

  Specific examples of the aliphatic polyoxyalkylene ether sulfate include polyoxyalkylene lauryl ether sulfate and polyoxyalkylene oleyl ether sulfate. Examples of the polyoxyalkylene lauryl ether sulfate include sodium polyoxyalkylene lauryl ether sulfate such as sodium polyoxyethylene lauryl ether sulfate and polyoxyalkylene lauryl ether ammonium sulfate such as ammonium polyoxyethylene lauryl ether sulfate. Examples of the polyoxyalkylene oleyl ether sulfate include sodium polyoxyalkylene oleyl ether sulfate such as sodium polyoxyethylene oleyl ether sulfate and sodium polyoxypropylene oleyl ether sulfate, and polyoxyalkylene oleyl ether ammonium sulfate. Among them, polyoxyalkylene lauryl ether sulfate, particularly sodium polyoxyalkylene lauryl ether sulfate is preferable, and particularly preferable results are obtained when sodium polyoxyethylene lauryl ether sulfate is used.

The fatty acid salt has the general formula [III]
R ³ COOM [III]
(Wherein R ³ represents an alkyl group having 5 to 24 carbon atoms or an alkenyl group having 5 to 24 carbon atoms, and M represents a sodium atom, a potassium atom, an ammonia group or an amino group). is there.

  Specific examples of fatty acid salts include, for example, oleate, stearate, laurate, myristate, palmitate, etc. Among them, oleate was used in particular. In some cases, favorable results are obtained.

The alkylbenzene sulfonate has the general formula [IV]
R ⁴ C ₆ H ₄ SO ₃ M
(Wherein R ⁴ represents an alkyl group having 5 to 24 carbon atoms, and M represents a sodium atom, a potassium atom, an ammonium group, or an amino group).

Specific examples of alkylbenzene sulfonates include linear alkylbenzene sulfonates, among which linear alkyl (C ₁₀ -C ₁₄ ) benzene sulfonates are preferred, especially dodecyl benzene sulfone. Favorable results are obtained when using acid salts, among them sodium dodecylbenzenesulfonate.

  The amount of the anionic surfactant added is usually required to be set to 1 to 15 parts by weight with respect to 100 parts by weight of the acrylic block copolymer, and is set to be 1 to 7 parts by weight. Is more preferable. When the ratio of the anionic surfactant is less than 1 part by weight, a stable aqueous dispersion may not be obtained. Conversely, if it exceeds 15 parts by weight, emulsification is facilitated, but it is uneconomical, and various physical properties of the anionic aqueous dispersion of the resulting acrylic block copolymer may be impaired.

  In addition to anionic surfactants, nonionic surfactants other than the above anionic surfactants or anionic or nonionic polymer dispersion stabilizers may be used in combination.

  Examples of nonionic surface activity include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sorbitan alkylate, oxyethylene oxypropylene block copolymer, and polyglycerin ester.

  On the other hand, examples of the polymer dispersion stabilizer include polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, hydroxypropyl cellulose, polyacrylate, polyacrylate salt, sodium alginate and the like.

  The anionic aqueous dispersion of the acrylic block copolymer of the present invention is not particularly limited as long as it is obtained by emulsifying and dispersing the acrylic block copolymer using an anionic surfactant. For example, as a production method thereof, (1) an organic phase in which an acrylic block copolymer is dissolved in an organic solvent and an aqueous phase in which an anionic surfactant is dissolved in water are mixed and emulsified, and then the organic solvent is added. (2) A method comprising stirring and emulsifying and dispersing an acrylic block copolymer under heating in the presence of an anionic surfactant in an aqueous medium, followed by cooling. It is done.

  As the method for producing the anionic aqueous dispersion of the acrylic block copolymer of the present invention, the method (1) is preferably used because the acrylic block copolymer is easily dissolved in an organic solvent.

  In the production method of (1) in the present invention, the organic solvent used in preparing the organic phase containing the acrylic block copolymer is not particularly limited, but usually benzene, toluene, xylene, etc. Aromatic hydrocarbon organic solvents. These organic solvents may be used alone or in combination of two or more. Furthermore, as a solubilizer, acyclic aliphatic hydrocarbon organic solvents such as pentane, hexane, heptane, and octane, lower ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, lower esters such as ethyl acetate and butyl acetate, Lower alcohols such as methanol, ethanol, isopropyl alcohol, and t-butanol may be used in combination.

  When preparing the organic phase, the dissolution ratio of the acrylic block copolymer is not particularly limited, but is preferably set so that the solid content concentration in the organic phase is 5 to 50% by weight. The melting temperature is not particularly limited, and it is usually dissolved at a temperature up to 100 ° C.

  When preparing an aqueous phase in which an anionic surfactant is dissolved, the surfactant is usually added and dissolved in water. At this time, the addition amount of the surfactant is not particularly limited, but is preferably set so that the concentration in the aqueous phase is 0.1 to 50% by weight.

  In the step of mixing and emulsifying the organic phase containing the acrylic block copolymer and the aqueous phase containing the surfactant, the mixing ratio of the organic phase and the aqueous phase is usually the aqueous phase relative to 100 parts by weight of the organic phase. The ratio is preferably set to 20 to 500 parts by weight, and more preferably set to 25 to 200 parts by weight. When the proportion of the aqueous phase is less than 20 parts by weight, emulsification may not be possible or the viscosity of the resulting emulsion may be very high. Conversely, if it exceeds 500 parts by weight, emulsification is possible, but productivity is poor and impractical.

  The method for mixing and emulsifying the organic phase and the aqueous phase is not particularly limited. For example, a method of stirring and mixing using an emulsifier having an appropriate shearing force, such as a homogenizer or a colloid mill, A method of dispersing and mixing using an ultrasonic disperser or the like can be employed, but a method of stirring and mixing is preferably employed. Moreover, the temperature at the time of emulsification is not particularly limited, but is preferably set in the range of 5 to 70 ° C.

  The anionic aqueous dispersion of the acrylic block copolymer of the present invention can be obtained by distilling off the organic solvent from the emulsion obtained by the above emulsification step. In general, the organic solvent can be distilled off according to a normal distillation method in which the emulsion is heated under reduced pressure, or a method in which steam is blown into the emulsion under reduced pressure. The anionic aqueous dispersion of the acrylic block copolymer thus obtained can be concentrated to a desired solid content concentration by an operation such as heat concentration, centrifugation or wet separation, if necessary.

  In the present invention, the average particle diameter of the acrylic block copolymer particles in the aqueous dispersion is preferably from 0.1 to 3 μm. When the average particle size is less than 0.1 μm, the stationary stability of the aqueous dispersion is increased, but the viscosity becomes high and handling may be difficult. On the other hand, when it exceeds 3 μm, the stationary stability of the aqueous dispersion may be lowered. In addition, this average particle diameter can be achieved by appropriately adjusting the stirring and mixing operation in the emulsification step.

  The anionic aqueous dispersion of the acrylic block copolymer of the present invention is obtained by emulsifying and dispersing acrylic block copolymer particles in an aqueous dispersion medium. The above-mentioned dialkyl sulfosuccinate and aliphatic Since an anionic surfactant represented by polyoxyalkylene ether sulfate, fatty acid salt, alkylbenzene sulfonate and the like is included, anionicity is imparted.

  In the anionic aqueous dispersion of the acrylic block copolymer, the filler, lubricant, stabilizer, plasticizer, flexibility imparting agent, flame retardant for the purpose of adjusting the physical properties of the resulting molded product and pressure-sensitive adhesive. , Pigments, antistatic agents, antibacterial and antifungal agents, and the like may be blended.

  Since the anionic aqueous dispersion of the acrylic block copolymer of the present invention contains the specific anionic surfactant as described above, the particle size of the dispersed acrylic block copolymer particles is small. In addition, it is excellent in storage stability, particularly stationary stability.

  By drying the anionic aqueous dispersion of the acrylic block copolymer of the present invention, molded articles such as films, films and sheets containing an anionic surfactant and an acrylic block copolymer can be obtained.

The molded article of the acrylic block copolymer obtained from the anionic aqueous dispersion of the acrylic block copolymer of the present invention is also one aspect of the present invention.
Although it does not specifically limit as temperature conditions for producing the said molded article, It is preferable to dry at the temperature of 40-200 degreeC.

  Since the anionic surfactant is excellent in thermal stability, the molded product of the acrylic block copolymer is not colored due to the anionic surfactant.

  Further, since the anionic surfactant is excellent in compatibility with the acrylic block copolymer, there is almost no bleeding of the anionic surfactant from the molded product of the acrylic block copolymer. .

  Therefore, the anionic aqueous dispersion of this acrylic block copolymer is a plastic molding, a coating agent for fibers, paper, films, etc., a raw material for foam rubber, a fiber or glass fiber converging agent, an adhesive, or a skin material. Widely used as a raw material for materials such as touch panels and other materials that require a good feel, sheets, films, panels, handles, grips, switches, sealing materials, hoses, tubes, belts, gaskets, and packing materials It is possible and has great industrial value.

  EXAMPLES Although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples. In the examples, BA, AA, and MMA each represent acrylic acid-n-butyl, acrylic acid, and methyl methacrylate. Moreover, the molecular weight described in the examples, the conversion rate of the polymerization reaction, and the evaluation of each physical property were performed according to the following methods.

<Molecular weight measurement method>
The molecular weight shown in this example was measured by the GPC analyzer shown below, and the molecular weight in terms of polystyrene was determined using chloroform as the mobile phase. As a system, a GPC system manufactured by Waters was used, and Shodex K-804 (polystyrene gel) manufactured by Showa Denko Co., Ltd. was used for the column.

<Method for measuring conversion rate of polymerization reaction>
The conversion rate of the polymerization reaction shown in this example was measured using the following analyzer and conditions.
Equipment used: Gas chromatography GC-14B manufactured by Shimadzu Corporation
Separation column: manufactured by J & W SCIENTIFIC INC, capillary column Supercoux-10, 0.35 mmφ × 30 m
Separation conditions: Initial temperature 60 ° C, hold for 3.5 minutes
Temperature increase rate 40 ° C / min
Final temperature 140 ° C, hold for 1.5 minutes
Injection temperature 250 ° C
Detector temperature 250 ° C
Sample preparation: The sample was diluted about 10 times with ethyl acetate, and butyl acetate or acetonitrile was used as an internal standard substance.

(Production Example 1)
Synthesis of MMA-BA-MMA (BA / MMA = 70/30 wt%) Acrylic Block Copolymer (hereinafter abbreviated as BA7) In order to obtain BA7, the following operation was performed.

  A 500-L reactor that had been purged with nitrogen and evacuated in vacuo was charged with a solution in which 6272 g of acetonitrile and BA, 8940 g had been mixed in advance, with the inside of the reactor being decompressed. Next, 813.7 g of cuprous bromide was charged, the temperature was raised to 68 ° C., and the mixture was stirred for 30 minutes. Thereafter, a mixed solution of BA, 48276.0 g and butyl acetate 1305.4 g, and a solution in which 339.0 g of diethyl 2,5-dibromoadipate were dissolved in 3528.0 g of acetonitrile were charged, and further heated to 75 ° C. Stirring was performed for 30 minutes. 98.2 g of pentamethyldiethylenetriamine was added to initiate polymerization of butyl acrylate as the first block. The polymerization rate was controlled by adding triamine as needed.

  When the conversion rate of BA reached 96%, 100249.6 g of toluene, 561.5 g of cuprous chloride, MMA, 31094.8 were charged, 98.2 g of pentamethyldiethylenetriamine was added, and MMA of the second block was added. Copolymerization was started. When the conversion rate of MMA reached 60%, 77940 g of toluene was added to dilute the reaction solution, and the reactor was cooled to stop the polymerization. When the GPC analysis of the obtained block copolymer was conducted, the number average molecular weight Mn was 104800, and molecular weight distribution Mw / Mn was 1.25. The composition analysis by NMR was BA / MMA = 70/30 (wt%).

  Toluene was added to the obtained block copolymer solution to adjust the polymer concentration to 25 wt%, and 728 g of p-toluenesulfonic acid was added, the inside of the reactor was purged with nitrogen, and the mixture was stirred at room temperature for 3 hours. The reaction solution was sampled and neutralized to confirm that the solution was colorless and transparent, and the reaction was stopped. Thereafter, the solution was dispensed, and solid-liquid separation was performed to remove the solid content. To this block copolymer solution, 1200 g of KYOWARD 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.) was added, the inside of the reactor was purged with nitrogen, and the mixture was stirred at room temperature for 1 hour. The reaction solution was sampled, and the reaction was stopped after confirming that the solution was neutral. Thereafter, the solution was discharged, and solid-liquid separation was performed to remove the adsorbent.

  The polymer solution was isolated by supplying the polymer solution to a horizontal evaporator with a vent port (manufactured by Kurimoto Iron Works Co., Ltd., horizontal evaporator SCP-100) to evaporate the solvent and unreacted monomers. The temperature of the trunk jacket and screw of the evaporator was adjusted to 180 ° C. with a heating medium, and the inside of the evaporator was kept at a reduced pressure of about 0.01 MPa or less by a vacuum pump. In this way, pellets of the title block copolymer were produced.

(Production Example 2)
Synthesis of MMA- (BA / AA) -MMA ((BA / AA) / MMA) = 70/30 wt%) type acrylic block copolymer (hereinafter abbreviated as BA7-COOH) Carboxyl group in polymer Was introduced with reference to WO2003 / 068888.

  Into a 500 L reaction vessel, 731 g of copper bromide was weighed and the inside of the reactor was purged with nitrogen. A solution prepared by mixing 6,272 g of acetonitrile and 57,010 mL of BA, 1,490 mL of TBA, and 1,032 mL of butyl acetate in a state where the reactor was decompressed was heated to 65 ° C. and stirred for 30 minutes. did. Thereafter, a solution in which 367 g of diethyl 2,5-dibromoadipate initiator was dissolved in 549 g of acetonitrile was charged into the reaction vessel, and further stirred for 30 minutes while raising the temperature to 85 ° C. 106 mL of pentamethyldiethylenetriamine was added to initiate BA / TBA copolymerization as the first block. When the conversion rate reached 96%, 92,023 g of toluene, 505 g of cuprous chloride and 23,993 mL of MMA were charged into the reactor, and 106 mL of pentamethyldiethylenetriamine was added to start polymerization of MMA as the second block. did. When the conversion rate reached 66%, 60,620 g of toluene was added to dilute the reaction solution, and the reaction vessel was cooled to stop the polymerization.

Toluene was added to the resulting reaction solution to make the polymer concentration 25% by weight. 1,779 g of p-toluenesulfonic acid was added to this solution, the inside of the reaction vessel was purged with nitrogen, and the mixture was stirred at 30 ° C. for 3 hours. The reaction solution was sampled to confirm that the solution was colorless and transparent, and 6,116 g of Radiolite # 3000 manufactured by Showa Chemical Industry was added. Thereafter, the reaction vessel was pressurized to 0.1 to 0.4 MPaG with nitrogen, and the solid content was separated using a pressure filter (filtration area 0.45 m ² ) equipped with a polyester felt as a filter medium.

  750 g of Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) was added to the obtained filtrate, and TBMA was added as an internal standard substance at 0.1 wt% with respect to 100 wt% of the filtrate. This solution was heated and stirred at 150 ° C. for 4 hours. After 4 hours, the solution was sampled, and it was confirmed that TBMA had disappeared by GC measurement.

  To the resulting solution, 9,275 g of Kyoward 500SH was added, the inside of the reaction vessel was purged with nitrogen, and the mixture was stirred at 30 ° C. for 1 hour. The solution was sampled, and it was confirmed that the solution was neutral. Thereafter, the reaction vessel was pressurized to 0.1 to 0.4 MPaG with nitrogen, and the solid content was separated using a pressure filter equipped with a polyester felt as a filter medium (filtration area 0.45 m 2) to obtain a polymer solution. . 750 g of Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) and 1,325 g of hydrotalcite DHT-4A-2 (manufactured by Kyowa Chemical Industry Co., Ltd.) as an acid trapping agent are added to the resulting polymer solution did.

Subsequently, the solvent component was evaporated from the polymer solution. As an evaporator, SCP100 (heat transfer area: 1 m ² ) manufactured by Kurimoto Steel Corporation was used. The heating medium oil at the evaporator inlet was set at 180 ° C., the vacuum degree of the evaporator was set at 90 Torr, the screw rotation speed was set at 60 rpm, and the supply speed of the polymer solution was set at 32 kg / h. A polymer was prepared. The average number of carboxyl groups per molecule was about 10.

  The conversion efficiency of the t-butyl ester moiety into a carboxyl group was measured by quantifying the amount of isobutylene generated from the t-butyl group by a 280 ° C. thermal decomposition reaction. As a result of the measurement, the conversion efficiency of the obtained resin was 95% or more.

  Thus, the target pellet of BA7-COOH was prepared. When the GPC analysis of the obtained block copolymer was performed, the number average molecular weight was 109,200 and molecular weight distribution Mw / Mn was 1.34.

(Production Example 3)
Synthesis of MMA-BA-MMA (BA / MMA = 65/35 wt%) type acrylic block copolymer (hereinafter abbreviated as BA6) The following operation was performed to obtain BA6.
88,506 g of BA was charged into a 500 L reactor that had been purged with nitrogen and then degassed under vacuum, with the inside of the reactor being decompressed. Next, 658.6 g of cuprous bromide was charged and stirred at 30 ° C. for 15 minutes. Thereafter, a solution prepared by dissolving 661.2 g of diethyl 2,5-dibromoadipate in 7,764.6 g of acetonitrile was charged, and the mixture was further stirred for 60 minutes while the temperature was raised to 75 ° C. 79.6 g of pentamethyldiethylenetriamine was added, and polymerization of BA serving as the first block was started. When the BA conversion rate reached 95%, 107,173 g of toluene, 454.5 g of cuprous chloride, 46,334.5 g of MMA were added, 79.6 g of pentamethyldiethylenetriamine was added, and MMA of the second block was added. Polymerization was started.

  Every 45 minutes, 79.6 g of pentamethyldiethylenetriamine was added, and when the MMA conversion rate reached 90%, 240,000 g of toluene was added to dilute the reaction solution and the reactor was cooled. When the GPC analysis of the obtained block copolymer was performed, the number average molecular weight Mn was 118,903 and molecular weight distribution Mw / Mn was 1.39. The composition analysis by NMR was BA / MMA = 70/30 (wt%). Toluene was added to the resulting block copolymer solution to adjust the polymer concentration to 25% by weight. To 1 kg of the resulting polymer solution, 5.5 g of p-toluenesulfonic acid was added, the inside of the reactor was replaced with nitrogen, and the jacket was heated. It was confirmed that the copper complex aggregated and became insoluble 7 hours after the internal temperature reached 148 ° C.

Further, 30 minutes later, cooling was started. After completion of cooling, 5.0 g of Radiolite # 3000 (manufactured by Showa Chemical Industry Co., Ltd.) was added as a filter aid, and the mixture was stirred at 30 ° C. for 30 minutes. The solid content was separated using a pressure filter. 13.45 g of Kyoward 500SH was added to about 4.50 kg of the block copolymer solution after filtration, the inside of the reaction vessel was purged with nitrogen, and the mixture was stirred at 30 ° C. for 1 hour. The reaction solution was sampled to confirm that the solution was neutral, and the reaction was completed. Thereafter, the reaction vessel was pressurized to 0.1 to 0.4 MPaG with nitrogen, and the solid content was separated using the above-described pressure filter equipped with polyester felt as a filter medium, and a (meth) acrylic block copolymer. A polymer solution containing was obtained.
The polymer solution was isolated by supplying the polymer solution to a horizontal evaporator with a vent port (manufactured by Kurimoto Iron Works Co., Ltd., horizontal evaporator SCP-100) to evaporate the solvent and unreacted monomers. The temperature of the trunk jacket and screw of the evaporator was adjusted to 180 ° C. with a heating medium, and the inside of the evaporator was kept at a reduced pressure of about 0.01 MPa or less by a vacuum pump. In this way, pellets of the title block copolymer were produced.

<Example 1>
Acrylic block copolymer BA 7; 30 g prepared in Production Example 1 and 170 g of toluene were added to a separable flask having an internal volume of 500 ml, and dissolved by stirring at 50 ° C. for 4 hours. An aqueous solution in which 1.5 g of sodium dioctylsulfosuccinate was dissolved in 100 g of water was added to the obtained toluene solution, and this was used with a homomixer (trade name “TK Homomixer M type” manufactured by Tokushu Kika Kogyo Co., Ltd.). And stirred for 2 minutes to obtain an emulsion. The rotation speed and temperature during stirring and mixing were set to 12,000 rpm and 40 ° C., respectively. The obtained emulsion was heated to 40 to 70 ° C. under reduced pressure of 40 to 90 kPa, and toluene was distilled off. As a result, an anionic aqueous dispersion of an acrylic block copolymer was obtained.

<Example 2>
30 g of acrylic block copolymer BA7-COOH prepared in Production Example 2 and 170 g of toluene were added to a separable flask having an internal volume of 500 ml and dissolved by stirring at 50 ° C. for 4 hours. An aqueous solution in which 1.5 g of sodium dioctylsulfosuccinate was dissolved in 100 g of water was added to the obtained toluene solution, and this was used with a homomixer (trade name “TK Homomixer M type” manufactured by Tokushu Kika Kogyo Co., Ltd.). And stirred for 2 minutes to obtain an emulsion. The rotation speed and temperature during stirring and mixing were set to 12,000 rpm and 40 ° C., respectively. The obtained emulsion was heated to 40 to 70 ° C. under reduced pressure of 40 to 90 kPa, and toluene was distilled off. As a result, an anionic aqueous dispersion of an acrylic block copolymer was obtained.

<Example 3>
30 g of acrylic block copolymer BA6 prepared in Production Example 2 and 170 g of toluene were added to a separable flask having an internal volume of 500 ml and dissolved by stirring at 50 ° C. for 4 hours. An aqueous solution in which 1.5 g of sodium dioctylsulfosuccinate was dissolved in 100 g of water was added to the obtained toluene solution, and this was used with a homomixer (trade name “TK Homomixer M type” manufactured by Tokushu Kika Kogyo Co., Ltd.). And stirred for 2 minutes to obtain an emulsion. The rotation speed and temperature during stirring and mixing were set to 12,000 rpm and 40 ° C., respectively. The obtained emulsion was heated to 40 to 70 ° C. under reduced pressure of 40 to 90 kPa, and toluene was distilled off. As a result, an anionic aqueous dispersion of an acrylic block copolymer was obtained.

<Example 4>
30 g of acrylic block copolymer BA7 prepared in Production Example 1 and 170 g of toluene were added to a separable flask having an internal volume of 500 ml, and dissolved by stirring at 50 ° C. for 4 hours. An aqueous solution in which 1.5 g of sodium polyoxyalkylene lauryl ether sulfate was dissolved in 100 g of water was added to the obtained toluene solution, and this was added to a homomixer (trade name “TK Homomixer M type” of Tokushu Kika Kogyo Co., Ltd.). The mixture was stirred and mixed for 2 minutes to obtain an emulsion. The rotation speed and temperature during stirring and mixing were set to 12,000 rpm and 40 ° C., respectively. The obtained emulsion was heated to 40 to 70 ° C. under reduced pressure of 40 to 90 kPa, and toluene was distilled off. As a result, an anionic aqueous dispersion of an acrylic block copolymer was obtained.

<Example 5>
30 g of acrylic block copolymer BA7 prepared in Production Example 1 and 170 g of toluene were added to a separable flask having an internal volume of 500 ml, and dissolved by stirring at 50 ° C. for 4 hours. An aqueous solution obtained by dissolving 1.5 g of potassium oleate in 100 g of water was added to the obtained toluene solution, and this was added using a homomixer (trade name “TK homomixer M type” manufactured by Tokushu Kika Kogyo Co., Ltd.). The mixture was stirred and mixed for 2 minutes to obtain an emulsion. The rotation speed and temperature during stirring and mixing were set to 12,000 rpm and 40 ° C., respectively. The obtained emulsion was heated to 40 to 70 ° C. under reduced pressure of 40 to 90 kPa, and toluene was distilled off. As a result, an anionic aqueous dispersion of an acrylic block copolymer was obtained.

<Example 6>
30 g of acrylic block copolymer BA7 prepared in Production Example 1 and 170 g of toluene were added to a separable flask having an internal volume of 500 ml and dissolved by stirring at 50 ° C. for 4 hours. An aqueous solution in which 1.5 g of sodium dodecylbenzenesulfonate was dissolved in 100 g of water was added to the obtained organic solution, and this was mixed with a homomixer (trade name “TK homomixer M type” manufactured by Tokushu Kika Kogyo Co., Ltd.). And stirred for 2 minutes to obtain an emulsion. The rotation speed and temperature during stirring and mixing were set to 12,000 rpm and 40 ° C., respectively. The obtained emulsion was heated to 40 to 70 ° C. under reduced pressure of 40 to 90 kPa, and toluene was distilled off. As a result, an anionic aqueous dispersion of an acrylic block copolymer was obtained.

<Comparative Example 1>
A nonionic aqueous dispersion of an acrylic block copolymer was obtained in the same manner as in Example 1 except that polyoxyethylene lauryl ether was used instead of sodium dioctyl sulfosuccinate in Example 1.

<Comparative example 2>
A cationic aqueous dispersion of an acrylic block copolymer was obtained in the same manner as in Example 1 except that octadecylamine acetate was used in place of sodium dioctylsulfosuccinate in Example 1.

<Comparative Example 3>
An anionic aqueous dispersion of an acrylic block copolymer was obtained in the same manner as in Example 1 except that 6 g of sodium dioctyl sulfosuccinate was used in Example 1.

<Comparative Example 4>
A latex was attempted in the same manner as in Example 1 except that 0.15 g of sodium dioctylsulfosuccinate was used in Example 1, but it became a lump when toluene was distilled off, and no aqueous dispersion was obtained.

<Comparative Example 5>
In Example 1, instead of BA7, a polystyrene-polybutadiene-polystyrene block copolymer, Kraton D-1102K (styrene content 28.5% by weight) (manufactured by Kraton Polymer Japan Co., Ltd.) was used. In the same manner as in Example 1, an anionic aqueous dispersion of a styrenic block copolymer was obtained.

<Comparative Example 6>
In the same manner as in Example 1 except that, instead of BA7, Shibster 103T (styrene content 30% by weight) (manufactured by Kaneka Corporation), which is a polystyrene-polyisobutylene-polystyrene block copolymer, was used instead of BA7. Operation was performed to obtain an anionic aqueous dispersion of a saturated styrene block copolymer.

Evaluation <Storage stability>
40 g of the aqueous dispersion obtained in Examples and Comparative Examples was put in a 50 ml container, sealed, and left in a temperature environment of 25 ° C. Then, after one month, the state of the aqueous dispersion was visually evaluated. The evaluation criteria are as follows.
○: No phase separation Δ: There is a phase that is slightly separated. ×: Phase separation is complete.

<Colorability>
An aqueous dispersion film was obtained by placing 2 g of the aqueous dispersion obtained in Examples and Comparative Examples on a 5 cm × 5 cm glass plate and drying at 40 ° C. for 12 hours. The state of this film was visually evaluated according to the following evaluation criteria.
○: The film is not colored ×: The film is colored.

<Surfactant bleed>
An aqueous dispersion film was obtained by placing 2 g of the aqueous dispersion obtained in Examples and Comparative Examples on a 5 cm × 5 cm glass plate and drying at 40 ° C. for 12 hours. The state of this film was visually evaluated according to the following evaluation criteria.
○: Surfactant is not bleeding from the surface of the film ×: Surfactant is slightly bleeding from the surface of the film

<Heat resistance>
The heat resistance shown in the examples and comparative examples was measured under the following conditions.

  An aqueous dispersion film was obtained by placing 2 g of the aqueous dispersion obtained in Examples and Comparative Examples on a 5 cm × 5 cm glass plate and drying at 40 ° C. for 12 hours. The obtained film was put on a glass plate and charged in an oven at 130 ° C. for 24 hours. ΔYI, which is the rate of change of YI before and after charging, was measured. YI was measured by a transmission method using a spectroscopic color difference meter SE-2000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

<Transparency>
Transparency shown in the examples and comparative examples was measured under the following conditions.
An aqueous dispersion film was obtained by placing 2 g of the aqueous dispersion obtained in Examples and Comparative Examples on a 5 cm × 5 cm glass plate and drying at 40 ° C. for 12 hours. The total light transmittance (TT) (%) of the obtained film was measured while attached to the glass plate.
For the measurement, a turbidimeter NDH-300A (manufactured by Nippon Denshoku Industries Co., Ltd.) was used.

<Oil resistance>
The heat resistance shown in the examples and comparative examples was measured under the following conditions.
An aqueous dispersion film was obtained by placing 2 g of the aqueous dispersion obtained in Examples and Comparative Examples on a 5 cm × 5 cm glass plate and drying at 40 ° C. for 12 hours.
One drop of IRM903 oil was dropped on the prepared film with a dropper and left at 110 ° C. for 24 hours, then wiped off with Kimwipe, and the wiped portion was visually observed.
Evaluation index No swelling: ○
What is swollen: ×
As evaluated.

<Ball tack test>
The tackiness shown in the examples and comparative examples was evaluated by the ball tack test shown below.
The ball tack test was performed according to JIS Z0237. The aqueous dispersion obtained in Examples and Comparative Examples was applied on a polyester film, dried at 40 ° C. for 12 hours, tested using a 5 cm run with an inclination angle of 30 °, and stopped on the film. Displayed by the ball number of the diameter.

From Examples 1 to 6 in Table 1, the anionic aqueous dispersion of the acrylic block copolymer obtained by the present invention is excellent in storage stability, and the film obtained from the aqueous dispersion is a bleed of surfactant. It turned out that there was no coloring.

  On the other hand, according to the methods of Comparative Examples 1 and 2, a nonionic or cationic aqueous dispersion can be obtained, but storage stability, coloring of the composition, and bleeding of the surfactant are observed. Further, a similar aqueous dispersion can be obtained even if anionic surfactant is used in a large amount as in the method of Comparative Example 3, but since the bleeding of the surfactant is seen from the composition, the anionic aqueous dispersion of the present invention is obtained. It was clear that had excellent properties.

  Further, from Examples 1 and 3 and Comparative Examples 5 and 6, the storage stability is excellent as compared with the conventional anionic aqueous dispersion of a styrenic block copolymer, and the heat resistance and transparency of the resulting film are excellent. It was found to be excellent in oil resistance and oil resistance. Transparency is derived from the fact that the acrylic block copolymer itself is excellent in transparency and has good dispersibility in water.

  Furthermore, from Example 1 and Comparative Examples 5 and 6, when compared with a film obtained from an aqueous dispersion of an acrylic block copolymer and a styrene block copolymer having the same hard segment content (wt%), The film obtained from the aqueous dispersion of the acrylic block copolymer was found to be superior in adhesive properties as compared to the film obtained from the aqueous dispersion of the styrene block copolymer. From this, it can use suitably as various adhesives and binders.

  According to the present invention, there is little load on the environment and the human body during processing, there is no coloring or surfactant bleed-out, and further, heat resistance, oil resistance, weather resistance, transparency, flexibility, Molded articles using acrylic block copolymers with excellent adhesion, etc. (such as skin materials, touch panel materials, sheets, films, panels, handles, grips, switches, etc. Parts, sealing materials) and adhesives can be obtained. It can also be used as a coating agent for various materials, a modifier such as an emulsion, a fiber sizing agent, and the like.

Claims (9)

  The acrylic block copolymer (A) comprising the methacrylic polymer block (a) and the acrylic polymer block (b) is 1 to 15 weights per 100 parts by weight of the acrylic block copolymer (A). An anionic aqueous dispersion of an acrylic block copolymer, which is emulsified and dispersed in water in the presence of a part of the anionic surfactant (B).   At least one monomer selected from the group consisting of acrylic polymer block (b) consisting of acrylic acid-n-butyl, ethyl acrylate, and 2-methoxyethyl acrylate, and these It is characterized by comprising 50 to 0% by weight of an acrylic acid ester and / or vinyl monomer other than acrylic acid-n-butyl, ethyl acrylate, and 2-methoxyethyl acrylate. An anionic aqueous dispersion of the acrylic block copolymer according to claim 1.   The methacrylic polymer block (a) comprises 50 to 100% by weight of methyl methacrylate and 0 to 50% by weight of a vinyl monomer copolymerizable therewith. An anionic aqueous dispersion of the acrylic block copolymer described in 1.   The acrylic block copolymer (A) has at least one functional group selected from the group consisting of an acid anhydride group, a carboxyl group, a hydroxyl group, and an epoxy group in one molecule. An anionic aqueous dispersion of the acrylic block copolymer according to any one of claims 1 to 3.   The anionic surfactant (B) is at least one selected from the group consisting of dialkyl sulfosuccinates, aliphatic polyoxyalkylene ether sulfates, fatty acid salts and alkylbenzene sulfonates. The anionic water dispersion of the acrylic block copolymer of any one of -4.   The acrylic block copolymer (A) in the anionic aqueous dispersion is in the form of particles having an average particle diameter of 0.1 to 3 µm, and the acrylic according to any one of claims 1 to 5 An anionic aqueous dispersion of a block copolymer.   A molded article of an acrylic block copolymer obtained from the anionic aqueous dispersion of the acrylic block copolymer (A) according to any one of claims 1 to 6.   The adhesive of the acrylic block copolymer obtained from the anionic water dispersion of the acrylic block copolymer (A) of any one of Claims 1-7.   Acrylic block copolymer (A) dissolved in an organic solvent and an anionic surfactant (B) dissolved in water are mixed and emulsified, and then the organic solvent is distilled off. The manufacturing method of the anionic aqueous dispersion of the acrylic block copolymer of any one of Claims 1-8.