JP3906493B2 - Method for producing macromonomer dispersion - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel method for producing a macromonomer used as a raw material for synthesizing a graft copolymer that gives high performance to paints, molding materials and adhesives.
[0002]
[Prior art and problems]
Macromonomer production methods include a method of converting a prepolymer synthesized by radical polymerization into a macromonomer (Japanese Patent Publication No. 43-11224), a living anion polymerization method (Japanese Patent Laid-Open No. 51-125186), group transfer heavy A combination method (Japanese Patent Laid-Open No. 62-62801) and an iniferter polymerization method are known.
In a method for producing a macromonomer comprising means for synthesizing a polymer skeleton by radical polymerization (hereinafter sometimes simply referred to as radical polymerization method) disclosed in the above Japanese Patent Publication No. 43-11224 and the like, There are advantages such as no need for purification and the use of functional group-containing monomers, and the radical polymerization method is most studied for practical use.
[0003]
In the radical polymerization method, the monomer is usually converted into a macromonomer polymer skeleton by solution polymerization. Next, a monomer having a reactive group is added to the polymer solution obtained by such polymerization, and the monomer and the terminal functional group of the polymer are reacted to synthesize a macromonomer. In this case, since the macromonomer is obtained in an organic solvent solution, the powdery macromonomer of the final product is produced by further removing the solvent and drying.
However, in the above method employing solution polymerization, there is a problem that blocking or polymerization is likely to occur, so that desolvation from the macromonomer is not easy, and odor due to residual monomer tends to remain in the macromonomer powder. .
[0004]
On the other hand, in the field of producing polymers used for paints and the like, a non-aqueous dispersion polymerization method is known as a polymerization method that makes it easy to separate and remove an organic solvent from a polymer. In the non-aqueous dispersion polymerization method, a poor solvent of the obtained polymer is used as a polymerization solvent, and a dispersant is used for the purpose of stabilizing the dispersion of the produced polymer particles. In order to obtain a stable polymer dispersion in the non-aqueous dispersion polymerization method, it is important to select a dispersant suitable for the monomer to be subjected to polymerization.
[0005]
Examples of applications of the non-aqueous dispersion polymerization method include a graft copolymer containing polyethylene oxide as a branch component, or a graft copolymer containing a polyester obtained by condensation polymerization of 12-hydroxystearic acid as a dispersant. There are some known techniques (Japanese Patent Publication No. 43-16147, Japanese Patent Laid-Open No. 1-18410, Japanese Patent Laid-Open No. 1-133403, etc.).
However, there is no known literature relating to the production of macromonomers by a non-aqueous dispersion polymerization method.
[0006]
[Problems to be solved by the invention]
The present invention solves the above-mentioned problems such as that the solvent removal from the macromonomer is not easy and the odor due to the residual monomer tends to remain in the macromonomer powder while maintaining the advantages of the radical polymerization method. An object of the present invention is to provide a method for producing a macromonomer.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the present invention is the major repeating unit is (meth) polymer is enabled with SP values alkyl acrylate monomer units is from 8.4 to 9.6, having a carboxyl group at one end of the molecule A radical polymerizable monomer having an epoxy group is added to a polymer dispersion in which a polymer (hereinafter sometimes referred to as a prepolymer) is dispersed in an aliphatic hydrocarbon or an alicyclic hydrocarbon, and the epoxy group and It is a method for producing a radical polymerizable macromonomer dispersion characterized by reacting the carboxyl group, and the macromonomer dispersion wherein the polymer dispersion, that is, the prepolymer dispersion is the following dispersion (1) It is a manufacturing method of a liquid.
[0008]
Dispersion (1): in a solvent consisting of an aliphatic hydrocarbon or alicyclic hydrocarbon, and none as a dispersant (a) the stem component and the branch component of the (meth) acrylic acid alkyl monomer unit components A graft copolymer having an SP value of the branch component of 8.4 to 9.6 and an SP value of the trunk component of 8.0 to 8.4, and a chain transfer agent (b) Copolymerization of an alkyl (meth) acrylate monomer or a monomer with another vinyl monomer to form a polymer having an SP value of 8.4 to 9.6 using a mercaptan having a carboxyl group. Then, a polymer having a SP value of 8.4 to 9.6 and having a carboxyl group at one end of the molecule is formed by radical polymerization of a vinyl monomer mixture in which other vinyl monomers are 10% by weight or less. Polymer dispersion.
[0009]
In the present invention, the reaction between the radical polymerizable monomer having an epoxy group and the terminal carboxyl group of the polymer serving as the macromonomer skeleton is a reaction between a liquid and a solid phase. Therefore, it is expected that the reaction yield of the above reaction will remain at a low level, but contrary to this expectation, in the present invention, a macromonomer with high purity could be obtained.
Hereinafter, the present invention will be described in more detail.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The prepolymer dispersion used in the present invention is the dispersion (1), and the dispersion (1) has a carboxyl group attributed to the carboxyl group-containing mercaptan of the chain transfer agent at one end of the molecule. In addition, an alkyl (meth) acrylate polymer having an SP value of 8.4 to 9.6, that is, the same polymer as the prepolymer is dispersed in the solvent. The SP value is an abbreviation for a Solubility Parameter value, that is, a solubility parameter. The SP value in the present invention is the document "Specific Interactions and the Miscibility of Polymer Blends" Michael M. It is identical to the SP value described in Coleman et al .; Technomic Publishing Co., Inc .; Pennsylvania USA (1991).
[0011]
As the aliphatic hydrocarbon or alicyclic hydrocarbon used in the production of the dispersion (1), those having an SP value of 8.4 or less are preferable, and specifically, straight chain such as hexane, heptane, octane and nonane. Or branched aliphatic saturated hydrocarbons; cycloaliphatic hydrocarbons such as cyclohexane and methylcyclohexane; and petroleum fractions such as petroleum ether, terpenes and swazoles. Particularly preferred aliphatic or alicyclic hydrocarbons are hexane, octane, cyclohexane and methylcyclohexane.
[0012]
The graft copolymer used in the preparation of the dispersion (1) is, as described above, a polymer both have to component (meth) alkyl monomer units acrylic acid stem component and the branch component, Katsue component The graft copolymer has an SP value of 8.4 to 9.6 and an SP value of the trunk component of 8.0 to 8.4. Preferred monomers for forming the branch component in the graft copolymer include alkyl having 1 to 4 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate and isobutyl (meth) acrylate. Examples thereof include alkyl (meth) acrylate having a group. According to the alkyl (meth) acrylate monomer having an alkyl group having 1 to 4 carbon atoms, a branch component having an SP value of 8.4 to 9.6 can be formed.
[0013]
The SP value of the prepolymer synthesized in the production of the dispersion liquid (1) is 8.4 to 9.6, and the closer the SP value is to the SP value of the branch component in the graft copolymer, the more is obtained. The stability of the dispersion is high.
When the SP value of the branch component of the graft copolymer is less than 8.4, the polymer particles produced in the non-aqueous dispersion polymerization are likely to block each other, while when the SP value of the same component exceeds 9.0, The compatibility of the graft copolymer with the aliphatic hydrocarbon or alicyclic hydrocarbon is poor, and the stability of the dispersed particles is poor.
[0014]
Preferred monomers for forming the trunk component in the graft copolymer include alkyl having 6 to 18 carbon atoms such as lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate and isobornyl (meth) acrylate. Examples thereof include alkyl (meth) acrylate having a group. According to such a monomer, a trunk component having an SP value of 8.0 to 8.4 can be formed.
[0015]
The graft copolymer has a polymer skeleton composed of an alkyl (meth) acrylate monomer unit having an alkyl group having 1 to 4 carbon atoms, and a radical polymerization having a number average molecular weight of 1,000 to 20,000. It can be easily synthesized by copolymerizing a functional macromonomer and an alkyl (meth) acrylate monomer having an alkyl group having 6 to 18 carbon atoms.
The preferred proportions of the radically polymerizable macromonomer and the alkyl (meth) acrylate monomer copolymerized therewith are 10 to 30% by weight of the macromonomer and 90 to 70% by weight of the copolymerized (meth) acrylate monomer. .
The amount of the graft copolymer used as a dispersion stabilizer at the time of polymerization is suitably 0.5 to 5 parts by weight per 100 parts by weight of an alkyl (meth) acrylate described later.
[0016]
Examples of the mercaptan having a carboxyl group used as a chain transfer agent include thioglycolic acid, 3-mercaptopropionic acid, 2-mercaptopropionic acid and mercaptobutyric acid. The amount used depends on the molecular weight of the target prepolymer, but is usually used in a proportion of 0.5 to 10 weights per 100 parts by weight of the alkyl (meth) acrylate monomer described later.
[0017]
The monomer used for polymerization in the production of the dispersion (1) is an alkyl (meth) acrylate monomer that forms a polymer having an SP value of 8.4 to 9.6, or the monomer as a main component. Specific examples of such alkyl (meth) acrylates having an alkyl group having 4 or less carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate and butyl (meth) acrylate An alkyl (meth) acrylate is mentioned.
Examples of the monomer that can be used in combination with the alkyl (meth) acrylate include vinyl acetate, styrene, (meth) acrylonitrile, fluorinated alkyl (meth) acrylate, N-alkoxymethyl (meth) acrylamide, and the like. The body can be used with a limit of about 10% by weight based on the total amount of all monomers in the vinyl monomer mixture mainly composed of the alkyl (meth) acrylate monomer.
[0018]
The polymerization temperature is preferably 60 to 150 ° C., and the polymerization initiator is preferably an azo radical generating compound, specifically, adibiscyclohexanecarbonitrile, azobismethylbutyronitrile, azobisisobutyronitrile and Abibisdimethylvaleronitrile and the like can be mentioned, and adibisdimethylvaleronitrile is particularly preferable.
By the above method, a polymer dispersion (1) that can be preferably used in the present invention is obtained. In the dispersion (1), an aliphatic hydrocarbon or alicyclic hydrocarbon has a (meth) acrylic acid alkyl monomer unit having an alkyl group having 4 or less carbon atoms as a main constituent unit, Prepolymer fine particles having a carboxyl group are dispersed.
[0020]
The synthesis of the macromonomer is performed as follows. That is, in order to add a radically polymerizable monomer having an epoxy group to the prepolymer dispersion and cause the carboxyl group in the prepolymer to react with the epoxy group in the terminal-modifying monomer, a temperature of 60 ° C. to 150 ° C. Heat at about 3 to 10 hours. At this time, since the prepolymer is dispersed in the reaction medium in the form of fine particles, the above reaction is apparently a liquid-solid heterogeneous reaction.
[0021]
As the radical polymerizable monomer having an epoxy group, glycidyl acrylate, glycidyl methacrylate, N- [4- (2,3 epoxypropoxy) -3,5 dimethylbenzyl] acrylamide and the like can be used. The preferable usage-amount is 1.05-3.0 times mole with respect to the total amount of the carboxyl group in the prepolymer made to react, More preferably, it is 1.05-1.30 times mole.
[0022]
Furthermore, in the macromonomerization reaction, a catalyst for improving the reaction efficiency or a polymerization inhibitor may be added to the reaction system.
As the catalyst, alkylamines or quaternary ammonium salts are preferable, and as the polymerization inhibitor, hydroquinone, hydroquinone monomethyl ether, P-phenylenediamine or the like can be used in an amount of 50 to 2,000 ppm.
[0023]
Hereinafter, the present invention will be described more specifically with reference to examples.
The dispersants D1 and D2 used in each example are graft copolymers having the following configurations.
(1) Dispersant D1; polymethyl methacrylate type macromonomer (number average molecular weight; 6,000, radical polymerizable group; methacryloyl group) and number average molecular weight obtained by copolymerizing 20 parts by weight of stearyl methacrylate Is a 13,000 graft copolymer.
(2) Dispersant D2: polyethyl methacrylate type macromonomer (number average molecular weight; 3,000, radical polymerizable group; methacryloyl group) and number average molecular weight obtained by copolymerizing 33 parts by weight of cyclohexyl methacrylate Is a graft copolymer of 10,400.
[0024]
[Example 1]
A. Preparation of Prepolymer Dispersion Dispersant D1; 2.0 g and cyclohexane 212.9 g were placed in a flask, heated to dissolve at 60 ° C. for 1 hour, and further charged with 100 g of methyl methacrylate and stirred under a nitrogen atmosphere. 80 ° C.
While adding 0.90 gr of 3-mercaptopropionic acid from the dropping funnel over 2 hours, 1.2 g of azobisdimethylvaleronitrile dissolved in cyclohexane was dripped from the other dropping funnel over 2 hours. Thereafter, by maintaining the above temperature for 4 hours, the polymerization was completed and the remaining polymerization initiator was decomposed.
By the above operation, a good dispersion liquid in which white turbid matters were dispersed was obtained. Furthermore, no deposits were observed on the inner wall or peller of the polymerization vessel.
Using a part of the obtained prepolymer dispersion, the particle size of the dispersed particles was measured with a laser / scattering particle size distribution device (Horiba LA-910), and the result was 3.2 μm. Moreover, as a result of measuring the average molecular weight of a prepolymer by GPC, it was Mn = 10,000 and Mw = 23,200 in polystyrene conversion.
[0025]
B. Production of Macromonomer Dispersion After the temperature of the prepolymer dispersion obtained by the above method was lowered to 50 ° C., 0.040 gr of hydroquinone monomethyl ether, 1.27 gr of glycidyl methacrylate and tetrabutylammonium bromide 0. 90 gr was charged and heated at 80 ° C. for 10 hours while bubbling air. As a result, the terminal carboxyl group in the prepolymer was converted to a methacryloyl group with a conversion rate of 99.5% (evaluated by measuring the acid value of the prepolymer). Thus, a cyclohexane dispersion of polymethyl methacrylate type radical polymerizable macromonomer was obtained.
[0026]
[Example 2]
Non-aqueous dispersion polymerization was performed in the same manner as in Example 1 using Dispersant D2 and ethyl methacrylate as a monomer to obtain a prepolymer dispersion.
As a result of measuring the average molecular weight of the prepolymer, it was Mn = 9,8000, Mw = 22,500 in terms of polystyrene, and the dispersed particle size was 3.0 μm.
Further, a macromonomer dispersion was obtained by reacting the prepolymer dispersion and glycidyl methacrylate in the same manner as in Example 1.
Since the macromonomer dispersion liquid obtained in Examples 1 and 2 is cyclohexane, which is a poor solvent for macromonomer, the solvent can be removed very easily.
[0027]
【The invention's effect】
According to the present invention, a macromonomer dispersion suitable for production of a powdery macromonomer can be obtained by an easy operation in terms of easy solvent removal.

Claims (1)

The polymer dispersion is the following dispersion (1), a radical polymerizable monomer having an epoxy group is added to the polymer dispersion, and the epoxy group and the carboxyl group are reacted with each other. A method for producing a polymerizable macromonomer dispersion.
Dispersion (1): In a solvent composed of an aliphatic hydrocarbon or an alicyclic hydrocarbon, as a dispersant, (a) both the trunk component and the branch component are composed of an alkyl (meth) acrylate monomer unit as a component . A graft copolymer having an SP value of the branch component of 8.4 to 9.6 and an SP value of the trunk component of 8.0 to 8.4, and a chain transfer agent (b) Copolymerization of an alkyl (meth) acrylate monomer or a monomer with another vinyl monomer to form a polymer having an SP value of 8.4 to 9.6 using a mercaptan having a carboxyl group. Then, a polymer having a SP value of 8.4 to 9.6 and having a carboxyl group at one end of the molecule is formed by radical polymerization of a vinyl monomer mixture containing 10% by weight or less of other vinyl monomers. Polymer dispersion.