JP2010084106A - Acrylic emulsion and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an acrylic emulsion excellent in wettability, compatibility, and adhesiveness to various materials. <P>SOLUTION: In the method for manufacturing an acrylic emulsion, a monomer represented by the structural formula or an acrylic monomer including an epoxy group or an acrylic monomer including a specific secondary amine is subjected to emulsion polymerization by using 0.020-0.400 mol of a polymerization initiator per 1.0 mol of an α-methylstyrene dimer in the presence of an acrylic prepolymer prepared by subjecting an acrylic monomer including an alkyl acrylate to bulk polymerization. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  An acrylic emulsion having good wettability, compatibility and adhesion to various materials and a method for producing the same are provided.

  Acrylic resins are abundant in the types of acrylic monomers that are used as raw materials, and the physical and chemical properties such as adhesion, adhesion, hardness, transparency, light resistance, weather resistance, and chemical resistance are optionally controlled. It can be used for a wide range of applications such as optical coatings for displays, lenses, optical films, adhesives and adhesives used in these, paints, sealing materials, paper strength enhancers, dental materials, aircraft and automotive parts And used.

  Acrylic resins generally generate a large amount of heat during polymerization and become more viscous as the polymerization progresses, so industrially compared heat removal such as solution polymerization, emulsion polymerization, and suspension polymerization using water or an organic solvent as a medium. It is often manufactured by an easy method. Further, when used for special purposes such as casting, it may be used as a partially polymerized syrup.

  A method for producing an acrylic macromonomer utilizing radical polymerization of an acrylic monomer and a method for producing an ABC or ABA block copolymer have been proposed (see Patent Document 1).

  The technology disclosed in Patent Document 1 is a copolymerization of a methacrylic acid alkyl ester and a methacrylic monomer having a carboxyl group, a hydroxyl group, an epoxy group, a tertiary amino group, etc., for example, a polypropylene resin , Nylon resin, Noryl resin, Polycarbonate resin, ABS resin, PPS resin and other plastics that occupy a major position in the organic polymer market, or Thermosetting epoxy resin, unsaturated polyester resin, phenol resin, polyurethane resin, etc. It does not give consideration to functional improvements such as compatibility with adhesive resin, wettability, and adhesiveness.

  In the technique proposed in Patent Document 1, the amount of 2,4-diphenyl-1--4-methyl-1-pentene and a polymerization initiator used with respect to an acrylic monomer is shown, but 2,4-diphenyl-1 The amount of the polymerization initiator used for -4-methyl-1-pentene (α-methylstyrene dimer) is not specified. Therefore, the heat removal at the time of manufacturing an acrylic macromonomer and an acrylic copolymer by radical polymerization becomes a big subject, and the manufacturing method of an acrylic macromonomer and an acrylic copolymer is limited. That is, it is limited to the case where an acrylic macromonomer and an acrylic copolymer are produced by a production method such as solution polymerization using an organic solvent that is easy to remove heat or emulsion polymerization using water as a medium.

When producing acrylic macromonomer and acrylic copolymer by solution polymerization according to the technique proposed in Patent Document 1, low molecular weight and low concentration containing a large amount of organic solvent due to concerns about stirring and heat removal during production. Only the acrylic macromonomer and the acrylic copolymer can be produced, and not only limited in use but also industrially less advantageous. Containing a large amount of organic solvent is not preferable from the viewpoint of environmental load.
JP 2000-169531 A

  Excellent wettability and compatibility with various materials such as polyolefin, typically polypropylene, which is a non-polar plastic that is difficult to adhere, and polyamide, typically nylon, which has polarity and is widely used as engineering plastic. An acrylic emulsion having solubility and adhesion is provided.

  The present invention is represented by the following structural formula using 0.020 to 0.400 mol of a polymerization initiator with respect to 1.0 mol of α-methylstyrene dimer.

(Here, R1 represents an alkyl group having 4 to 12 carbon atoms.)
It is represented by the following structural formula in the presence of an acrylic prepolymer obtained by bulk polymerization of an acrylic monomer containing an alkyl acrylate ester.

(Where X represents a hydrogen atom or a methyl group, Y represents the following chemical structure

Or the following chemical structure

(Where R2 is a hydrogen atom (H) or the following chemical structure

Represents. ). )
A method for producing an acrylic emulsion in which an acrylic monomer containing at least one vinyl monomer is emulsion-polymerized.

  The present invention is a method for producing an acrylic emulsion in which a compound having a specific bulky chemical structure is emulsion-polymerized in the presence of an acrylic prepolymer obtained by bulk polymerization of an acrylic monomer containing an acrylic acid alkyl ester. The acrylic emulsion is good for various materials such as polyolefin, which is represented by polypropylene, which is a non-polar plastic, which is considered to be difficult to adhere, and polyamide, which is polar and has been widely used as engineering plastic. It has wettability, compatibility, and adhesiveness.

  The acrylic emulsion produced in the present invention is useful as a compatibilizing polymer of different polymer materials such as polycarbonate resin and ABS resin. In addition, the acrylic emulsion produced in the present invention has higher strength by improving dispersion stability, compatibility, and adhesion between functional reinforcing materials such as glass fiber, carbon fiber, aramid fiber, and titanium whisker and matrix resin. Composite materials can be manufactured.

  The present invention is represented by the following structural formula using 0.020 to 0.400 mol of a polymerization initiator with respect to 1.0 mol of α-methylstyrene dimer.

(Here, R1 represents an alkyl group having 4 to 12 carbon atoms.)
It is represented by the following structural formula in the presence of an acrylic prepolymer obtained by bulk polymerization of an acrylic monomer containing an alkyl acrylate ester.

(Where X represents a hydrogen atom or a methyl group, Y represents the following chemical structure

Or the following chemical structure

(Where R2 is a hydrogen atom (H) or the following chemical structure

Represents. ). )
A method for producing an acrylic emulsion in which an acrylic monomer containing at least one vinyl monomer is emulsion-polymerized.

  In the method for producing an acrylic emulsion of the present invention, α-methylstyrene dimer used for producing an acrylic prepolymer is represented by the following structural formula,

2,4-diphenyl-4-methyl-1-pentene. In the method for producing an acrylic emulsion of the present invention, α-methylstyrene dimer is produced and marketed by Nippon Oil & Fats Co., Ltd., Goi Kasei Co., Ltd., Honshu Chemical Industry Co., Ltd., Asahi Kasei Finechem Co., Ltd. Any one can be selected and used.

  In the method for producing an acrylic emulsion of the present invention, the α-methylstyrene dimer used in producing the acrylic prepolymer is preferably reversible when 80% by weight or more of the acrylic monomer used in the acrylic prepolymer is an acrylate monomer. Additive open-chain chain transfer agent (generally called RAFT agent. RAFT is an abbreviation for Reversible Addition-Fragmentation Chain Transfer; hereinafter also referred to as RAFT agent). At the same time, the radical polymerization reaction proceeds by so-called living radical polymerization in which the number average molecular weight increases linearly.

  In the method for producing an acrylic emulsion of the present invention, the polymerization initiator used for producing the acrylic prepolymer is an organic peroxide such as benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, or t-butylperoxybenzoate. Oxides, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile And organic azo polymerization initiators such as 2,2-azobis [2- (2-imidazolin-2-yl) propane]. In the method for producing an acrylic emulsion of the present invention, these polymerization initiators may be used alone or in a mixture of two or more.

  In the method for producing an acrylic emulsion of the present invention, among these polymerization initiators, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2 , 4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 2,2-azobis [2- (2-imidazolin-2-yl) propane] and the like are recommended. In addition, safety during the production of the acrylic prepolymer is ensured, and the radical polymerizability as the prepolymer is improved.

  In the method for producing an acrylic emulsion of the present invention, the polymerization initiator is 0.020 to 0.400 mol, preferably 0.050 to 0.335 mol, more preferably 1.0 mol relative to 1.0 mol of α-methylstyrene dimer. , 0.010 to 0.250 mol is preferably used. In the method for producing an acrylic emulsion of the present invention, when the amount of the polymerization initiator used is less than 0.020 mol, a practically satisfactory polymerization rate can be obtained at an industrially reasonable production time when producing the acrylic prepolymer. I can't. In the method for producing an acrylic emulsion according to the present invention, when the amount of the polymerization initiator used exceeds 0.400 mol, it is difficult to remove heat and stir during the production of the acrylic prepolymer, so that the acrylic prepolymer can be made safe and stable. Cannot be manufactured.

  In the method for producing an acrylic emulsion of the present invention, the practically satisfactory polymerization rate of the acrylic prepolymer is preferably 85% or more, more preferably 90% or more, and further preferably 95% or more. In the method for producing an acrylic emulsion according to the present invention, when the polymerization rate of the acrylic prepolymer is 85% or more, there is little generation of aggregates during the production of the acrylic emulsion, and sharp performance is achieved by compatibility with polypropylene and nylon and wettability. There is a tendency to produce acrylic emulsions that exhibit.

  In the method for producing an acrylic emulsion of the present invention, the polymerization initiator is preferably used with respect to 100 parts by weight of the acrylic monomer used for the acrylic prepolymer in order to more safely control the polymerization temperature during the production of the acrylic prepolymer. Is preferably 0.05 to 5 parts by weight, more preferably 0.08 to 3 parts by weight, and still more preferably 0.10 to 2.5 parts by weight. In the manufacturing method of the acrylic emulsion of this invention, when the usage-amount of a polymerization initiator is 0.05-5 weight part, the tendency for abnormal polymerization reaction and rapid heat_generation | fever to become hard to occur is seen.

  In the method for producing an acrylic emulsion of the present invention, the acrylic prepolymer is produced by bulk polymerization.

  In the method for producing an acrylic prepolymer of the present invention, bulk polymerization for producing an acrylic prepolymer includes an acrylic monomer containing an alkyl acrylate ester, α-methylstyrene dimer, and 1.0 mol of α-methylstyrene dimer. A polymerization initiator used in an amount of 0.020 to 0.4000 mol is charged into an acrylic prepolymer production vessel, heated to a predetermined polymerization temperature, stirred, and temperature-controlled while radical polymerization until a predetermined polymerization rate is reached. It is a manufacturing method which performs.

  In the case of general bulk polymerization, a large heat of polymerization that occurs rapidly and a viscosity that rapidly increases with the progress of polymerization make stirring and heat removal difficult, leading to runaway reactions and explosions. There are many problems in industrial production, which has the potential to lead to serious disasters, and whose greatest mission is to produce safely and stably. In addition, insufficient stirring and heat removal tend to cause quality deterioration such as polymer burning due to local heating and higher degree of polymerization.

  In the method for producing an acrylic emulsion according to the present invention, the acrylic prepolymer is produced by bulk polymerization using 0.020 to 0.400 mol of a polymerization initiator with respect to 1.0 mol of α-methylstyrene dimer. In addition, concerns such as stirring at the time of acrylic prepolymer production, runaway reaction due to insufficient heat removal, and deterioration of quality due to local heating are eliminated, and the acrylic prepolymer can be produced safely and stably.

  In the method for producing an acrylic emulsion of the present invention, α-methylstyrene dimer preferably acts as a reversible addition-cleavage type chain transfer agent and as a polymerization inhibitor. In the method for producing an acrylic emulsion of the present invention, an α-methylstyrene dimer is used by using 0.020 to 0.400 mol of a polymerization initiator with respect to 1.0 mol of α-methylstyrene dimer when producing an acrylic prepolymer. As a polymerization inhibitor, the polymerization rate of acrylic monomers containing dicyclopentenyloxyethyl acrylate is controlled appropriately, abrupt heat generation and viscosity increase due to rapid polymerization reaction are alleviated, and industrial temperature Control is possible, and an acrylic prepolymer can be produced safely and stably.

  In the method for producing an acrylic emulsion of the present invention, the gas phase oxygen concentration of the acrylic prepolymer production vessel substituted with inert gas is preferably 0.0 vol% ≦ gas phase oxygen concentration ≦ 8.0 vol%, more preferably Is preferably carried out in an atmosphere of 0.02 vol% ≦ gas phase oxygen concentration ≦ 8.0 vol%, and more preferably 0.02 vol% ≦ gas phase oxygen concentration ≦ 6.0 vol%. In the method for producing an acrylic emulsion of the present invention, if the gas phase oxygen concentration during the production of the acrylic prepolymer is 0.0 vol% ≦ gas phase oxygen concentration ≦ 8.0 vol%, the acrylic monomer is contained in the gas phase portion. An acrylic prepolymer can be produced safely and efficiently without causing a polymerization reaction.

  In the method for producing an acrylic emulsion of the present invention, the oxygen concentration in the polymerization system during the production of the acrylic prepolymer is determined by using a “digital oximeter XO-326ALB” (oxygen concentration measuring instrument from New Cosmos Electric Co., Ltd.). It was measured. Moreover, in the manufacturing method of the acrylic emulsion of this invention, the inert gas used by this invention can be arbitrarily selected from what is marketed, such as nitrogen gas and helium gas.

  Furthermore, in the method for producing an acrylic emulsion of the present invention, when the gas phase oxygen concentration is controlled by blowing an inert gas or an inert gas / air mixed gas at the time of producing the acrylic prepolymer, the inert gas is used. Alternatively, it is recommended that the inert gas / air mixed gas be at a temperature sufficiently low that radical polymerization of the acrylic monomer is not initiated. In the method for producing an acrylic emulsion of the present invention, from this viewpoint, the temperature of the inert gas or the inert gas / air mixed gas is preferably as low as possible, but is preferably 40 ° C. or less, more preferably 30 ° C. or less, It is recommended that the temperature be 25 ° C. or lower. In the method for producing an acrylic emulsion of the present invention, if the temperature of the inert gas or the mixed gas of inert gas / air is preferably 40 ° C. or less, the acrylic monomer vapor present in the gas phase part of the acrylic prepolymer production vessel The acrylic monomer tends to be less likely to cause radical polymerization in the gas phase part of the acrylic prepolymer production vessel, the vessel wall, the condenser, etc., and the acrylic prepolymer can be produced more safely.

  In the method for producing an acrylic emulsion of the present invention, the polymerization temperature for producing the acrylic prepolymer is preferably 50 to 100 ° C., more preferably 60 to 100 ° C., further preferably 70 to 98 ° C. . In the method for producing an acrylic emulsion of the present invention, when the polymerization temperature during the production of the acrylic prepolymer is 50 to 100 ° C., there is a tendency that stirring and heat removal can be carried out quantitatively, and the production can be performed safely and stably. There is a trend. In addition, even when relatively low boiling point acrylic monomers such as methyl methacrylate and ethyl acrylate are copolymerized, it is safer to produce a large amount of monomer vapor during production. There is a tendency to become possible.

  In the method for producing an acrylic emulsion of the present invention, the acrylic prepolymer is produced up to a predetermined polymerization temperature, preferably 60 to 300 minutes, more preferably 90 to 300 minutes, and still more preferably 90 to 180 minutes. It is recommended to warm and conduct bulk polymerization. In the method for producing an acrylic emulsion of the present invention, the radical polymerization reaction proceeds quantitatively and faster when stirring time is increased when the temperature rise time to the predetermined polymerization temperature is preferably 60 to 300 minutes during the production of the acrylic prepolymer. There is a tendency that heat can be made easier and manufacturing operations can be carried out more safely. In the method for producing an acrylic emulsion of the present invention, it should be noted that if the temperature rising time during the production of the acrylic prepolymer is 90 minutes or more, the function of the α-methylstyrene dimer as the RAFT agent becomes even more remarkable. There is a tendency for the number average molecular weight to increase linearly with the increase in the polymerization rate, and the tendency for the production of acrylic prepolymer to proceed by living radical polymerization becomes remarkable. That is, by using the produced acrylic prepolymer at the time of emulsion polymerization, it is easy to produce an AB block copolymer, and there is a tendency to further improve the compatibility, wettability, and adhesion to polypropylene and nylon. .

  In the method for producing an acrylic emulsion of the present invention, the acrylic prepolymer is represented by the following structural formula.

(Here, R1 represents an alkyl group having 4 to 12 carbon atoms.)
An acrylic monomer containing an acrylic acid alkyl ester is used.

  In the method for producing an acrylic emulsion of the present invention, the alkyl acrylate is selected from the group consisting of n-butyl acrylate, t-butyl acrylate, i-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and acrylic acid. Examples include isobornyl and the like. In the method for producing an acrylic emulsion of the present invention, these acrylic monomers may be used alone or in a mixture of two or more.

  In the method for producing an acrylic emulsion of the present invention, among these acrylic acid alkyl esters, preferably, cyclohexyl acrylate and isobornyl acrylate are exemplified. In the method for producing an acrylic emulsion according to the present invention, an acrylic monomer having a bulky alicyclic structure such as cyclohexyl acrylate and isobornyl acrylate is used as the acrylic prepolymer, so that polypropylene, nylon, etc. of the acrylic emulsion are used. Compatibility, wettability, and adhesion are improved.

  In the method for producing an acrylic emulsion of the present invention, the alkyl acrylate used in the acrylic prepolymer is preferably 20 to 100 wt%, with the total amount of acrylic monomers used in the acrylic prepolymer being 100 wt%. %, More preferably 20 to 98% by weight, still more preferably 30 to 95% by weight. In the method for producing an acrylic emulsion of the present invention, when the amount of these acrylic acid alkyl esters used in the acrylic prepolymer is 20 to 100% by weight, the compatibility of the acrylic emulsion with polypropylene, nylon, etc., wettability, Adhesion is improved.

  In the method for producing an acrylic emulsion of the present invention, the acrylic prepolymer is represented by the following structural formula.

(Here, R1 represents an alkyl group having 4 to 12 carbon atoms.)
In addition to alkyl acrylates, preferably, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tertiary butyl methacrylate, cyclohexyl methacrylate, methacrylic acid (Meth) acrylic acid alkyl ester monomers such as 2-ethylhexyl, lauryl methacrylate, benzyl methacrylate, isobornyl methacrylate, carboxyl group-containing acrylic monomers such as acrylic acid and methacrylic acid, 2-hydroxyethyl acrylate, Hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, polyethylene glycol mono Hydroxyl group-containing acrylic monomers such as acrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate, polypropylene glycol monomethacrylate, polytetramethylene glycol monoacrylate, polytetramethylene glycol monomethacrylate, N, N-dimethylaminoethyl acrylate, N, Tertiary amino group-containing acrylic monomers such as N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine Hindered amino group-containing acrylic monomers such as 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine, acrylamide N, N-dimethylacrylamide, N-isopropylacrylamide, hydroxymethylacrylamide, hydroxyethylacrylamide, N, N-dimethylaminopropylacrylamide, 2-acrylamide-2-methyl-propanesulfonic acid, diacetone acrylamide, N-methoxymethylacrylamide Amide group-containing acrylic monomers such as N-ethoxymethylacrylamide, N-butoxymethylacrylamide, 4-methacrylamidoethylethyleneurea, urea group-containing acrylic monomers such as 2-methacryloyloxyethyl-ethyleneurea, acrylic acid Contains epoxy groups such as glycidyl, methyl glycidyl acrylate, glycidyl methacrylate, methyl glycidyl methacrylate, vinylbenzyl glycidyl ether Acrylic monomers such as acrylic monomers, dicyclopentenyloxyethyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentenyloxy acrylate, dicyclopentenyloxy methacrylate, and other dicyclopentadiene derivative acrylic monomers can be used. In the method for producing an acrylic emulsion of the present invention, these acrylic monomers may be used alone or in a mixture of two or more.

  In the method for producing an acrylic emulsion of the present invention, it is represented by the following structural formula used for the acrylic prepolymer.

(Here, R1 represents an alkyl group having 4 to 12 carbon atoms.)
Among acrylic monomers other than acrylic acid alkyl esters, it is recommended to use an acrylate monomer in order to produce an acrylic prepolymer by living radical polymerization and produce a radical polymerization active acrylic prepolymer. In the method for producing an acrylic emulsion of the present invention, acrylate monomers preferably used for the acrylic prepolymer include acrylic acid, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, acrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, hydroxymethylacrylamide, hydroxyethylacrylamide, N, N-dimethylaminopropylacrylamide, 2-acrylamide-2-methyl-propanesulfonic acid, diacetone acrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, Acrylamide derivatives such as N-butoxymethylacrylamide, glycidyl acrylate, vinylbenzyl glycidyl ether, dicyclopentenyloxyethyl Acrylate, etc. dicyclopentanyl acrylate are exemplified. In the method for producing an acrylic emulsion of the present invention, if these acrylate monomers are used, the production of the acrylic prepolymer proceeds by living radical polymerization, becomes a radical polymerization active acrylic prepolymer, and blocks by emulsion polymerization. There is a tendency that the copolymer can be produced efficiently.

  In the method for producing an acrylic emulsion of the present invention, the number average molecular weight of the acrylic prepolymer is preferably 500 to 80000, more preferably 1000 to 60000, and still more preferably 2000 to 60000. In the method for producing an acrylic emulsion of the present invention, when the number average molecular weight of the acrylic prepolymer is preferably 500 to 80000, the compatibility of the acrylic emulsion with polypropylene, nylon, polyester, etc., wettability, and adhesion are improved. There is a trend.

  Here, in the method for producing an acrylic emulsion of the present invention, the molecular weight of the acrylic prepolymer is determined by using gel permeation chromatography (GPC) “HLC-8220GPC” (test equipment of Tosoh Corporation), the carrier being tetrahydrofuran, Measurement was performed using polystyrene as a molecular weight standard.

  In the method for producing an acrylic emulsion of the present invention, the acrylic prepolymer used in the present invention is usually a radical polymerization active acrylic copolymer. In the method for producing an acrylic emulsion of the present invention, since a new acrylic monomer is radically polymerized in the presence of the acrylic prepolymer, the acrylic emulsion is produced from an acrylic prepolymer (A segment) and a newly radically polymerized acrylic monomer. In many cases, an AB block copolymer composed of an acrylic polymer (B segment) is produced.

  In the method for producing an acrylic emulsion of the present invention, it is represented by the following structural formula in the presence of an acrylic prepolymer.

(Where X represents a hydrogen atom or a methyl group, Y represents the following chemical structure

Or the following chemical structure

(Where R2 is a hydrogen atom (H) or the following chemical structure

Represents. ). )
An acrylic emulsion is produced by emulsion polymerization of an acrylic monomer containing one or more vinyl monomers.

  In the method for producing an acrylic emulsion of the present invention, it is represented by the following structural formula.

(Where X represents a hydrogen atom or a methyl group, Y represents the following chemical structure

Or the following chemical structure

(Where R2 is a hydrogen atom (H) or the following chemical structure

Represents. ). )
As the vinyl monomer, when X is a hydrogen atom, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, acrylic acid, glycidyl acrylate, 4-acryloyloxy-2,2 , 6,6-tetramethylpiperidine, N- (2-acryloylethyl) ethyleneurea, when X is a methyl group, methacrylic acid, glycidyl methacrylate, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine N- (2-methacryloyloxyethyl) ethyleneurea and the like. In the method for producing an acrylic emulsion of the present invention, these vinyl monomers may be used alone or in a mixture of two or more.

  In the method for producing an acrylic emulsion according to the present invention, among these vinyl monomers, o-vinylbenzylglycidyl ether, m- Vinyl benzyl glycidyl ether, p-vinyl benzyl glycidyl ether, methacrylic acid, glycidyl methacrylate, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine, N- (2-methacryloyloxyethyl) ethylene urea are desirable.

  In the method for producing an acrylic emulsion of the present invention, these vinyl monomers are preferably 0.5 to 60% by weight, more preferably 0.5 to It is desirable to use 55% by weight, more preferably 0.5 to 50% by weight. In the method for producing an acrylic emulsion of the present invention, when the amount of vinyl monomer used is 0.5 to 60% by weight, the crosslinkability and storage stability of the acrylic emulsion are improved, and a polymer material such as polypropylene and nylon, There is a tendency to exhibit good compatibility, wettability and adhesion to inorganic materials such as glass fiber and carbon fiber.

  In the method for producing an acrylic emulsion of the present invention, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, and p-vinylbenzyl glycidyl ether (hereinafter also referred to as vinylbenzyl glycidyl ether) that are preferably used as vinyl monomers are: The total amount of acrylic monomers used in the emulsion polymerization is 100% by weight, preferably 3 to 50% by weight, more preferably 5 to 30% by weight, and still more preferably 5 to 25% by weight. In the method for producing an acrylic emulsion of the present invention, when the amount of o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, and p-vinylbenzyl glycidyl ether used is 3 to 50% by weight, the acrylic emulsion such as nylon or polyester is used. There is a tendency that the compatibility with a polar polymer and the wettability are further improved, and that the crosslinkability is further improved to become a tough polymer.

  In the method for producing an acrylic emulsion of the present invention, an acrylic monomer containing a specific vinyl monomer is emulsion-polymerized in the presence of a specific acrylic prepolymer.

  As described above, in the method for producing an acrylic emulsion of the present invention, among specific vinyl monomers, o-vinyl is used from the viewpoint of chemical properties, chemical properties such as water resistance, and crosslinkability among acrylic emulsions. Benzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, methacrylic acid, glycidyl methacrylate, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine, N- (2-methacryloyloxyethyl) ) Ethylene urea is preferred.

  In the method for producing an acrylic emulsion of the present invention, methacrylic acid is preferably 1 to 25% by weight, more preferably 3 to 16% by weight, more preferably 3 to 16% by weight, with the total amount of acrylic monomers used for emulsion polymerization being 100% by weight. It is desirable to use 5 to 12% by weight. In the method for producing an acrylic emulsion of the present invention, when the amount of methacrylic acid used is 1 to 25% by weight, there is a tendency that aggregation does not easily occur during the production of the acrylic emulsion. In addition, the cohesive strength of the acrylic emulsion is improved, and there is a tendency that the wettability and adhesion to metals such as iron, aluminum alloy, glass and mortar and inorganic materials are improved.

  In the method for producing an acrylic emulsion of the present invention, glycidyl methacrylate is preferably 3 to 50% by weight, more preferably 3 to 45% by weight, with the total amount of acrylic monomers used for emulsion polymerization being 100% by weight. More preferably, it is desirable to use 3 to 30% by weight. In the method for producing an acrylic emulsion according to the present invention, when the amount of glycidyl methacrylate used is 3 to 50% by weight, the compatibility of the acrylic emulsion with polar polymers such as nylon and polyester, and the tendency to improve wettability are observed. There is a tendency that the crosslinkability is improved and a tough polymer is obtained. At the same time, there is a tendency to improve wettability and adhesion to metals such as iron, aluminum alloy, glass and mortar, and inorganic materials.

  In the method for producing an acrylic emulsion of the present invention, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine is preferably 0.1%, with the total amount of acrylic monomers used for emulsion polymerization being 100% by weight. It is desirable to use 5 to 30% by weight, more preferably 3 to 28% by weight, and still more preferably 3 to 25% by weight. In the method for producing an acrylic emulsion of the present invention, when the amount of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine used is 0.5 to 30% by weight, the polarity of the acrylic emulsion such as nylon or polyester There is a tendency that compatibility with polyolefins such as polymers, polypropylene, polyethylene, polyisoprene, polybutadiene and the like are improved, and there is a tendency that crosslinkability is improved and a tough polymer is obtained. There is also a tendency to improve the dispersibility and adhesion of functional fibers such as carbon fibers, glass fibers, and titanium whiskers in the matrix resin, and to provide a tough fiber-reinforced composite material.

  In the method for producing an acrylic emulsion of the present invention, N- (2-methacryloyloxyethyl) ethylene urea is preferably 1 to 30% by weight, preferably 100% by weight, and more preferably 1 to 30% by weight, based on the total amount of acrylic monomers used for emulsion polymerization. It is desirable to use 1.5 to 28% by weight, more preferably 3 to 25% by weight. In the method for producing an acrylic emulsion of the present invention, when the amount of N- (2-methacryloyloxyethyl) ethylene urea used is 1 to 30% by weight, the acrylic emulsion is a polar polymer such as nylon or polyester, polypropylene, polyethylene, poly There is a tendency for compatibility with polyolefins such as isoprene and polybutadiene, and a tendency to improve wettability, and a tendency for crosslinkability to be improved to become a tough polymer. There is also a tendency to improve the dispersibility and adhesion of functional fibers such as carbon fibers, glass fibers, and titanium whiskers in the matrix resin, and to provide a tough fiber-reinforced composite material.

  In the method for producing an acrylic emulsion of the present invention, an acrylic monomer that undergoes emulsion polymerization is represented by the following structural formula.

It is desirable to include dicyclopentenyloxyethyl methacrylate.

  In the method for producing an acrylic emulsion of the present invention, dicyclopentenyloxyethyl methacrylate is marketed such as “FANCYL FA-512M” (product of Hitachi Chemical), “QM-657” (product of Rohm and Haas). You can select any of these.

  In the acrylic emulsion of the present invention, dicyclopentenyloxyethyl methacrylate is preferably 20 to 98% by weight, more preferably 20 to 95% by weight, with the total amount of acrylic monomers used for emulsion polymerization being 100% by weight, More preferably, it is desirable to use 30 to 95% by weight. In the method for producing an acrylic emulsion of the present invention, when the amount of dicyclopentenyloxyethyl methacrylate used is 20 to 98% by weight, functions such as compatibility, wettability, and adhesiveness of the acrylic emulsion tend to be further improved. It is done.

  In the method for producing an acrylic emulsion of the present invention, preferably, by using dicyclopentenyloxyethyl methacrylate having a bulky molecular structure and an allylic unsaturated bond derived from dicyclopentadiene, a polypropylene resin, a nylon resin, Various plastics such as noryl resin, polycarbonate resin, ABS resin, PPS resin, etc. that occupy a major position in the market, or thermosetting resins such as epoxy resin, unsaturated polyester resin, phenol resin, polyurethane resin, etc. There is a tendency to improve and improve compatibility with materials, adhesion, and wetting. Moreover, the adhesiveness with alloys, such as iron, aluminum, magnesium, titanium, is favorable, and the tendency to exhibit the outstanding rust prevention property is seen.

  In the method for producing an acrylic emulsion of the present invention, an acrylic monomer containing a specific vinyl monomer is emulsion-polymerized in the presence of a specific acrylic prepolymer. In the method for producing an acrylic emulsion of the present invention, the emulsion polymerization may be produced by any well-known emulsion polymerization such as a monomer dropping method, an emulsion dropping method, or seed emulsion polymerization.

  In emulsion polymerization, an anionic emulsifier such as dodecylbenzenesulfonic acid or a nonionic emulsifier such as polyoxyethylene alkylphenyl ether is usually used to stably emulsify and disperse the acrylic monomer in water, or a positive An ionic emulsifier is used, and a water-soluble persulfate such as ammonium persulfate or potassium persulfate is used as a polymerization initiator, and the polymerization is performed at a temperature of 30 to 100 ° C.

  In the method for producing an acrylic emulsion of the present invention, it is preferable to carry out emulsion polymerization using a water-soluble organic azo polymerization initiator, preferably using an anionic reactive emulsifier having an allyl group in the molecule.

  In the method for producing an acrylic emulsion of the present invention, when a water-soluble organic azo polymerization initiator is used for emulsion polymerization, the pH of the produced acrylic emulsion during emulsion polymerization is usually 4.0 to 10.0. During the emulsion polymerization and storage of the acrylic emulsion, for example, a functional group useful as a functional polymer such as an epoxy group or an alkoxysilane group, and a highly active functional group is not lost by the reaction. There is a tendency that it can be used for a long time as a polymer having high activity and high functionality.

  In the method for producing an acrylic emulsion of the present invention, the pH / 25 ° C. of the acrylic emulsion produced during emulsion polymerization is preferably 4.0 to 10.0, more preferably 4.5 to 9.8, Preferably, it is 4.5 to 9.7. In the method for producing an acrylic emulsion of the present invention, during emulsion polymerization and when the pH / 25 ° C. of the produced acrylic emulsion is preferably 4.0 to 10.0, during emulsion polymerization and storage of the produced acrylic emulsion. There is a tendency that a functional group which is active and functionally effective is not lost, and it is stably retained for a long time until it is applied as a compatibilizing polymer or adhesive.

  In the method for producing an acrylic emulsion of the present invention, the water-soluble organic azo polymerization initiator is represented by the following structural formula.

A water-soluble organic azo polymerization initiator having an imidazoline group in the molecule such as 2,2-azobis [2- (2-imidazolin-2-yl) propane], which is represented by the following structural formula

2,2-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], represented by the following structural formula

In the molecule such as 2,2-azobis [2-methyl-N- (2-carboxyethyl) -2-methylpropionamidine] hydrate, amide group -C (O) NH-, amidine group -C (N) NH And water-soluble organic azo polymerization initiators having-. In the method for producing an acrylic emulsion of the present invention, these water-soluble organic azo polymerization initiators may be used alone or in a mixture of two or more.

  In the method for producing an acrylic emulsion of the present invention, in order to adjust the pH of the acrylic emulsion to preferably 4.0 to 10.0, it is preferably represented by the following structural formula.

2,2-Azobis [2- (2-imidazolin-2-yl) propane] is recommended.

  In the method for producing an acrylic emulsion of the present invention, the water-soluble organic azo polymerization initiator is preferably 0.1 to 5. preferably, based on 100 parts by weight of the total amount of acrylic monomers including the vinyl monomer to be emulsion polymerized. It is desirable to use 0 parts by weight, more preferably 0.15 to 2.5 parts by weight, and still more preferably 0.2 to 2.0 parts by weight. In the method for producing an acrylic emulsion of the present invention, when the water-soluble organic azo polymerization initiator is used in an amount of 0.1 to 5.0 parts by weight, the generation of aggregates is small, and the polymerization rate is appropriately adjusted. There is a tendency for the amount of reaction monomer to decrease.

  In the method for producing an acrylic emulsion of the present invention, the anionic reactive emulsifier having an allyl group in the molecule can be arbitrarily selected from those on the market. As anionic reactive emulsifiers having an allyl group in the marketed molecule, “Latemul PD-104” (polyoxyalkylene alkenyl ether ammonium sulfate) (Kao product), “Aqualon KH-1025” (Daiichi Kogyo) Pharmaceutical product), “Adekalysorb SR-1025” (25% aqueous solution of ammonium salt of (α-sulfo-ω-((1-alkoxymethyl-2-propenyloxy) ethoxy-polyoxy-1,2-ethanediyl)) ( Asahi Denka Kogyo Co., Ltd.) In the method for producing an acrylic emulsion of the present invention, an anionic reactive emulsifier having an allyl group in these molecules may be used alone or in combination of two or more. May be used.

  In the method for producing an acrylic emulsion of the present invention, when an anionic reactive emulsifier having an allyl group in the molecule is used as an emulsifier for emulsion polymerization, an acrylic emulsion having good emulsion stability and low residual monomer is produced. There is a trend.

  In the method for producing an acrylic emulsion of the present invention, more preferably, it is represented by the following structural formula

(Here, R2 represents an alkyl group having 8 to 24 carbon atoms.)
An anionic reactive emulsifier having an allyl group in the molecule is recommended.

  In the method for producing an acrylic emulsion of the present invention, it is represented by the following structural formula.

(Here, R2 represents an alkyl group having 8 to 24 carbon atoms.)
Examples of the anionic reactive emulsifier having an allyl group in the molecule include “Adeka Resorb SR-1025”.

In the method for producing an acrylic emulsion of the present invention, it is more preferable that R2 is —C ₁₁ H ₂₃ (α-sulfo-ω-((1-undecanoxymethyl-2-propenyloxy) ethoxy-polyoxy-1,2- Ethanediyl) ammonium salt is preferred.

  In the method for producing an acrylic emulsion of the present invention, when an anionic reactive emulsifier having an allyl group in these molecules is used, an acrylic emulsion having very good emulsification stability and a small amount of residual monomer is produced. There is a trend. In addition, it is easy to control the particle size of the acrylic emulsion, and there is a tendency that an acrylic emulsion with enhanced functionality can be produced.

  In the method for producing an acrylic emulsion of the present invention, the anionic reactive emulsifier having an allyl group in the molecule is an acrylic prepolymer, an acrylic monomer containing a vinyl monomer, and an anion having an allyl group in the molecule. The total amount of ionic reactive emulsifiers is preferably 100 to 20% by weight, preferably 1 to 20% by weight, more preferably 1.5 to 20% by weight, and still more preferably 1.8 to 16% by weight. In the method for producing an acrylic emulsion of the present invention, when the amount of the anionic reactive emulsifier having an allyl group in the molecule is 1 to 20% by weight, the emulsion stability is good and the emulsion polymerization proceeds smoothly, There is a tendency that an acrylic emulsion with less aggregates can be produced.

  The acrylic emulsion produced by the method for producing an acrylic emulsion of the present invention comprises a water-soluble organic azo polymerization initiator for emulsion polymerization and a vinyl monomer when an anionic reactive emulsifier having an allyl group in the molecule is used. When the functional group is a carboxyl group (for example, methacrylic acid), the pH / 25 ° C. of the acrylic emulsion is 4.0 to 7.0, and when the functional group of the vinyl monomer is an epoxy group (for example, Vinyl benzyl glycidyl ether, glycidyl methacrylate), acrylic emulsion having a pH / 25 ° C. of 6.0 to 8.0, and the vinyl monomer has an amino group (for example, 4-methacryloyloxyethyl- 2,2,6,6-tetramethylpiperidine), acrylic emulsion pH / 25 ° C. is 8.0 to 10.0, vinyl Of the case where the functional group is a urea group (e.g., N-(2-methacryloyloxyethyl) ethylene urea), the pH / 25 ° C. of the acrylic emulsion becomes 7.0 to 10.0.

  Therefore, in the acrylic emulsion produced by the method for producing an acrylic emulsion of the present invention, the acrylic prepolymer (A) is usually present in a larger amount in the inner shell of the acrylic emulsion particle, and an acrylic monomer containing a vinyl monomer that undergoes emulsion polymerization. It is presumed that the polymer (B) composed of a body is present in the outer shell of the acrylic emulsion particle in a larger amount, and further, an AB block copolymer in which A and B are bonded by a covalent bond of carbon atom-carbon atom. Since the acrylic emulsion produced by the method for producing an acrylic emulsion of the present invention has this unique acrylic emulsion structure and polymer morphology, polypropylene, polyolefin represented by polyisoprene, nylon, polyetheretherketone, polyphenylene sulfide, It is presumed that compatibility, wettability and adhesion to engineering plastics represented by nonyl resin and the like, and polymer alloys thereof are more emphasized and expressed. At the same time, it exhibits wettability, adhesion and corrosion resistance to iron, aluminum alloy, copper alloy, titanium alloy, magnesium alloy and the like.

  The details of the present invention will be described in the following examples. In the following examples, the evaluation method, measurement method, and the like were as follows.

1) Heating residue (%)
Measured according to JIS K 5407: 1997. In addition, the measurement was heat-dried at 140 ° C. for 1 hour.

2) Polymerization rate (%)
The heating residue was measured according to JIS K 5407: 1997, and this was defined as the polymerization rate. In addition, the measurement was heat-dried at 140 ° C. for 1 hour.

3) pH / 25 ° C
Measurement was performed at 25 ° C. using a pH meter.

4) Particle size (nm)
Measurement was performed using a dense particle size analyzer “FPAR-1000” manufactured by Otsuka Electronics.

5) Number average molecular weight (Mn), weight average molecular weight (Mw)
Gel permeation chromatography (GPC) “HLC-8220GPC” (test equipment of Tosoh Corporation) was used, and measurement was performed using tetrahydrofuran as a carrier and polystyrene as a molecular weight standard. The molecular weight distribution was calculated by Mw / Mn.

6) Adhesiveness A cross cut test was performed according to JIS K 5400: 1997.

  Dilute the acrylic emulsion with ion-exchanged water to a concentration of 20%, add 1.0% of “DYNOL406” (air products paint additive; antifoaming, wet agent), and then add it to the polypropylene test piece. The coating was applied so that the coating thickness was 10 μm. After drying at 140 ° C. for 30 minutes, the adhesion test was performed.

7) Oxygen concentration (vol%)
The measurement was performed using a digital oximeter XO-326ALB (a measuring device manufactured by Shin Cosmos Electric Co., Ltd.).

8) Living radical polymerizability of acrylic prepolymer Sampling was performed during the production of the acrylic prepolymer to prepare a graph of polymerization rate-number average molecular weight. Living radical polymerizability was good (◯) when the number average molecular weight increased almost linearly with respect to the increase in the polymerization rate. On the other hand, when the number average molecular weight hardly increased from the initial stage of polymerization, the living radical polymerizability was poor (Δ), or the number average molecular weight decreased was regarded as no living radical polymerizability (×). In the case of (circle), it was suitable for acrylic emulsion manufacture and was set as the pass.

9) Solvent resistance The acrylic emulsion was diluted with ion-exchanged water to a concentration of 20%, and after adding 1.0% of “DYNOL406” (air products paint additive; It apply | coated so that the coating-film thickness might be set to 10 micrometers on the test piece made from a polypropylene. Dry at 140 ° C. for 30 minutes. The coated film was rubbed with absorbent cotton soaked with acetone, and the dissolved state of the coated film was evaluated.
○ The coating film did not change even after rubbing 50 times or more. The film was whitened but not dissolved after 20 times when the solvent resistance was good and passed. × Accepted × The coating film dissolved only by rubbing several times. It was rejected due to poor solvent resistance.

10) Stability of acrylic emulsion The acrylic emulsion was allowed to stand at 23 ° C for 1 week, and the state of separation and precipitation was evaluated.
○ It was stable without separation and precipitation (pass)
X Separation occurred, and a clear layer was formed in the upper layer part (failed).

Example 1
Nitrogen gas was blown into a 2 L four-necked flask equipped with a stirrer, nitrogen gas inlet, reflux condenser, and temperature sensor, and it was confirmed that the oxygen concentration in the flask was 3.0 vol% or less. Thereafter, nitrogen gas blowing was continued during the production of the acrylic prepolymer P-1. The gas phase temperature in the flask was 25 ° C.

  The flask was charged with 1000 g of cyclohexyl acrylate, 28.5 g of α-methylstyrene dimer (MSD), and 10.0 g of 2,2′-azobis (2,4-dimethylvaleronitrile). At this time, the liquid temperature of the acrylic monomer mixture was 22 ° C., and the oxygen concentration in the gas phase was 2.0 vol% or less. The temperature increase was started, and the temperature was raised from 30 ° C. to a polymerization temperature of 95 ° C. in 120 minutes. After raising the temperature, polymerization was carried out for 8 hours, and acrylic prepolymer P-1 was produced by bulk radical polymerization.

  During the production of the acrylic prepolymer P-1, no sudden heat generation or viscosity increase was observed, and the production was safe. The acrylic prepolymer showed good living radical polymerizability.

  The acrylic prepolymer P-1 had a polymerization rate of 98.5%, a number average molecular weight of 25200, a weight average molecular weight of 46600, and a molecular weight distribution of 1.85.

  Table 1 shows the details of the polymerization formulation and the characteristic values of the acrylic prepolymer P-1. In the table, (1) is an acrylic monomer, (2) an α-methylstyrene dimer (MSD) which is a RAFT agent, (3) is a polymerization initiator, (4) is a polymerization condition of the acrylic prepolymer, ( 5) showed the characteristic value of the acrylic prepolymer.

  Nitrogen gas was blown into a 1 L four-necked flask equipped with a stirrer, a nitrogen gas blowing port, a reflux condenser, and a temperature sensor, and the atmosphere in the flask was replaced with nitrogen gas. Thereafter, blowing of nitrogen gas was continued during the production of acrylic emulsion AE-1.

  Table 3 shows the composition, production method, and characteristic values of the acrylic emulsion AE-1. The flask was charged with 118.5 g of (3) ion-exchanged water (initial charge) in Table 3 that had been deoxygenated by bubbling nitrogen gas, and the temperature was raised. At 60 ° C., 1.0 g of (5) polymerization initiator 2,2-azobis [2- (2-imidazolin-2-yl) propane] in Table 3 was added, and the mixture was stirred at 60 ° C. for 60 minutes. Was dissolved in ion-exchanged water. The temperature increase was started and the temperature was increased to 63 ° C.

  In Table 3, (1) acrylic prepolymer P-125 g, (2) acrylic monomer mixture (dicyclopentenyloxyethyl methacrylate 65 g, isobornyl methacrylate 5 g, methacrylic acid 5 g) 75 g, (3) ion-exchanged water (emulsification) For use) 45.1 g, (4) Adeka Resorb SR-1025 (an anionic reactive emulsifier having an allyl group in the molecule, manufactured by Asahi Denka Kogyo Co., Ltd.) 25,000 g using an emulsifier For 10 minutes to prepare a pre-emulsion.

  30% by weight of the pre-emulsion was added to the flask and heated to 75 ° C. After emulsion polymerization at 75 ° C. for 60 minutes, the remaining amount of 70% by weight of the pre-emulsion was fed into the flask in 2 hours. After completion of the feed, emulsion polymerization was further carried out for 60 minutes, the mixture was cooled to 40 ° C. or lower, and (3) 114.3 g of ion-exchanged water (for dilution) was added to produce an acrylic emulsion AE-1.

  The acrylic emulsion AE-1 had a heating residue of 24.2%, a pH / 25 ° C. of 4.6, and a particle size of 110 nm.

  As shown in Table 3, since acrylic emulsion AE-1 uses cyclohexyl acrylate for the acrylic prepolymer and dicyclopentenyloxyethyl methacrylate for the acrylic emulsion, compatibility with polypropylene, wettability and adhesion Was good. The stability of the acrylic emulsion was also good. The solvent resistance was in an acceptable range for practical use.

  In Table 3, (1) is an acrylic prepolymer, (2) is an acrylic monomer, (3) is ion-exchanged water, and (4) Adekalysorb SR-1025 has an anionic reactivity having an allyl group in the molecule. “Adekariasorb SR-1025” (manufactured by Asahi Denka Kogyo Co., Ltd.) as an emulsifier, (5) is a water-soluble organic azo polymerization initiator having an imidazoline bond in the molecule (2,2-azobis [2- (2-imidazoline-2 -Il) propane]), (6) shows the characteristic values of the acrylic emulsion, and (7) shows adhesion to polypropylene, solvent resistance, and stability of the acrylic emulsion.

Examples 2-20
Acrylic prepolymers P-2 to P-4 were produced in the same manner as in Example 1 except that the composition and production conditions of the acrylic prepolymer were changed as shown in Table 1 (acrylic prepolymers P-2 to P-4). Compositions and production methods of acrylic emulsions are shown in Table 3 (acrylic emulsions AE-2 to AE-7), Table 4 (acrylic emulsions AE-8 to AE-13), and Table 5 (acrylic emulsions AE-14 to AE-20). Acrylic emulsions AE-2 to AE-20 were produced in the same manner as in Example 1 except for changing.

  In Table 1, (1) is an acrylic monomer, (2) α-methylstyrene dimer which is a RAFT agent, (3) is a polymerization initiator, (4) is a polymerization condition of an acrylic prepolymer, and (5) is an acrylic. The characteristic values of the prepolymer are shown.

  In Tables 3, 4 and 5, (1) is an acrylic prepolymer, (2) is an acrylic monomer, (3) is ion-exchanged water, and (4) Adekariasorb SR-1025 has an allyl group in the molecule. An anionic reactive emulsifier “Adekariasorb SR-1025” (manufactured by Asahi Denka Kogyo), (5) is a water-soluble organic azo polymerization initiator having an imidazoline bond in the molecule (2,2-azobis [2- ( 2-Imidazolin-2-yl) propane]), (6) shows the characteristic values of the acrylic emulsion, and (7) shows the adhesion to polypropylene, the solvent resistance, and the stability of the acrylic emulsion.

  As shown in Table 1, the acrylic prepolymer could be produced safely without problems and troubles such as stirring and heat removal. In addition, it showed good living radical polymerizability.

  As shown in Table 3, Table 4, and Table 5, the acrylic emulsion could be produced without any problems. Further, since cyclohexyl acrylate was used for the acrylic prepolymer and dicyclopentenyloxyethyl methacrylate was used for the acrylic emulsion, the compatibility with polypropylene and the wettability were good, and the adhesion was excellent. The stability of the acrylic emulsion was also good. An acrylic emulsion using a carboxyl group (methacrylic acid) or an epoxy group (glycidyl methacrylate, vinylbenzyl glycidyl ether) as a functional group showed a solvent resistance level at which there is no practical problem.

  The amino group (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine) and the urea group (N- (2-methacryloyloxyethyl) ethyleneurea) showed good solvent resistance.

  An acrylic emulsion obtained by emulsion polymerization of a carboxyl group-containing acrylic monomer (methacrylic acid) had a low pH / 25 ° C. and became an acidic side. An acrylic emulsion obtained by emulsion polymerization of an epoxy group-containing acrylic monomer (glycidyl methacrylate, vinylbenzyl glycidyl ether) became neutral to weakly alkaline at pH / 25 ° C. An acrylic emulsion obtained by emulsion polymerization of an amino group-containing acrylic monomer (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine) had an alkali side of pH / 25 ° C. An acrylic emulsion obtained by emulsion polymerization of a urea group-containing acrylic monomer (N- (2-methacryloyloxyethyl) ethylene urea) became weakly alkaline to alkaline at pH / 25 ° C. All acrylic emulsions were subjected to emulsion polymerization in the presence of an acrylic prepolymer produced by living radical polymerization to produce a block copolymer, and the pH / 25 ° C. was as designed.

  The produced acrylic emulsion showed good solvent resistance. In particular, an acrylic emulsion obtained by emulsion polymerization of an amino group-containing acrylic monomer (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine), a urea group-containing acrylic monomer (N- (2-methacryloyloxyethyl) Acrylic emulsion obtained by emulsion polymerization of) ethylene urea) had good solvent resistance. Furthermore, as shown in Table 5, when a functional group was used in the acrylic prepolymer, it had excellent solvent resistance.

Comparative Example 1
Nitrogen gas was blown into a 2 L four-necked flask equipped with a stirrer, nitrogen gas inlet, reflux condenser, and temperature sensor, and it was confirmed that the oxygen concentration in the flask was 3.0 vol% or less. Thereafter, nitrogen gas blowing was continued during the production of the acrylic prepolymer P-5. The gas phase temperature in the flask was 25 ° C.

  The flask was charged with 1000 g of dicyclopentenyloxyethyl methacrylate, 95.0 g of α-methylstyrene dimer, and 10.0 g of 2,2′-azobis (2,4-dimethylvaleronitrile). At this time, the liquid temperature of the acrylic monomer mixture was 22 ° C., and the oxygen concentration in the gas phase was 2.0 vol% or less. The temperature increase was started and the temperature was increased from 30 ° C. to the polymerization temperature of 85 ° C. in 120 minutes. After raising the temperature, polymerization was carried out for 4 hours, and acrylic prepolymer P-5 was produced by bulk radical polymerization.

  During the production of the acrylic prepolymer P-5, no sudden heat generation or viscosity increase was observed, and the production was safe. During the production of acrylic prepolymer P-5, the number average molecular weight decreased as the polymerization rate increased. The acrylic prepolymer P-5 did not show living radical polymerization.

  The acrylic prepolymer P-5 had a polymerization rate of 98.8%, a number average molecular weight of 8300, a weight average molecular weight of 18500, and a molecular weight distribution of 2.23.

  Table 2 shows the details of the polymerization formulation and the characteristic values of the acrylic prepolymer P-5. In the table, (1) is an acrylic monomer, (2) is an α-methylstyrene dimer that is a RAFT agent, (3) is a polymerization initiator, (4) is a polymerization condition of the acrylic prepolymer, (5) Indicates the characteristic value of acrylic prepolymer. Table 6 shows the composition, production method, and characteristic values of the acrylic emulsion AE-21.

  Nitrogen gas was blown into a 1 L four-necked flask equipped with a stirrer, a nitrogen gas blowing port, a reflux condenser, and a temperature sensor, and the atmosphere in the flask was replaced with nitrogen gas. Thereafter, blowing of nitrogen gas was continued during the production of acrylic emulsion AE-21.

  Nitrogen gas was bubbled into the flask and 118.5 g of (3) ion-exchanged water (initial charge) in Table 5 that had been deoxygenated in advance was charged, and the temperature was raised. At 60 ° C., 1.0 g of (5) polymerization initiator 2,2-azobis [2- (2-imidazolin-2-yl) propane] in Table 5 was added, and the mixture was stirred at 60 ° C. for 60 minutes. Was dissolved in ion-exchanged water. The temperature increase was started and the temperature was increased to 63 ° C.

  (1) Acrylic prepolymer P-525 g in Table 6, (2) Acrylic monomer mixture (dicyclopentenyloxyethyl methacrylate 65 g, isobornyl methacrylate 5 g, methacrylic acid 5 g) 75 g, (3) ion-exchanged water (emulsified) 45.1g, (4) "Adeka Resorb SR-1025" (an anionic reactive emulsifier having an allyl group in the molecule manufactured by Asahi Denka Kogyo Co., Ltd.) 21.1g of a mixture was used at 5000 revolutions using an emulsifier. Emulsification for 10 minutes produced a pre-emulsion.

  30% by weight of the pre-emulsion was added to the flask and heated to 75 ° C. After emulsion polymerization at 75 ° C. for 60 minutes, the remaining amount of 70% by weight of the pre-emulsion was fed into the flask in 2 hours. After completion of the feed, emulsion polymerization was further carried out for 60 minutes, the mixture was cooled to 40 ° C. or lower, and (3) 114.3 g of ion exchange water (for dilution) was added to produce an acrylic emulsion AE-21.

  The acrylic emulsion AE-21 had a heating residue of 23.4%, a pH / 25 ° C. of 4.6, and a particle size of 580 nm. Acrylic emulsion AE-21 had an abnormally large particle size and poor acrylic emulsion stability. Moreover, the solvent resistance was inferior for practical use.

  In Table 6, (1) is an acrylic prepolymer, (2) is an acrylic monomer, (3) is ion-exchanged water, and (4) Adecare Sorb SR-1025 is an anionic reactive emulsifier having an allyl group in the molecule. “Adekariasorb SR-1025” (manufactured by Asahi Denka Kogyo), (5) is a water-soluble organic azo polymerization initiator having an imidazoline bond in the molecule (2,2-azobis [2- (2-imidazoline-2- Yl) propane]), (6) shows the characteristic values of the acrylic emulsion, and (7) shows adhesion to polypropylene, solvent resistance, and stability of the acrylic emulsion.

Comparative Examples 2-4
Acrylic prepolymers P-5 to P-8 were produced in the same manner as in Comparative Example 1 except that the composition and production conditions of the acrylic prepolymer were changed as shown in Table 2 (acrylic prepolymers P-5 to P-8). Acrylic emulsions AE-21 to AE-24 were produced in the same manner as in Comparative Example 1 except that the composition and production method of the acrylic emulsion were changed as shown in Table 6 (acrylic emulsions AE-21 to AE-24).

  In Table 2, (1) is an acrylic monomer, (2) α-methylstyrene dimer which is a RAFT agent, (3) is a polymerization initiator, (4) is a polymerization condition of an acrylic prepolymer, and (5) is an acrylic. The characteristic values of the prepolymer are shown.

  In Table 6, (1) is an acrylic prepolymer, (2) is an acrylic monomer, (3) is ion-exchanged water, and (4) Adecare Sorb SR-1025 is an anionic reactive emulsifier having an allyl group in the molecule. “Adekariasorb SR-1025” (manufactured by Asahi Denka Kogyo), (5) is a water-soluble organic azo polymerization initiator having an imidazoline bond in the molecule (2,2-azobis [2- (2-imidazoline-2- Yl) propane]), (6) shows the characteristic values of the acrylic emulsion, and (7) shows adhesion to polypropylene, solvent resistance, and stability of the acrylic emulsion.

  As can be seen in the production of acrylic prepolymer P-8 in Table 2, when the amount ratio of α-methylstyrene dimer, which is the RAFT agent, and the polymerization initiator is not appropriate, the bulk of the acrylic prepolymer due to the rapid and large heat of polymerization. Polymerization could not be performed.

  Acrylic emulsions AE-21 to AE-24 have no acrylic acid alkyl ester monomer in the acrylic prepolymers P-5, P-6, and P-7 used. Although it seems to be caused by macrophase separation, the particle size was enlarged abnormally, and separation and precipitation tendency occurred. In acrylic emulsions AE-21 to AE-24, clear layer separation of the emulsion occurred within one week.

  As shown in Table 6, since acrylic emulsions AE-21 to AE-24 use dicyclopentenyloxyethyl methacrylate for both the acrylic prepolymer and the emulsion, polypropylene is derived from the molecular structure of dicyclopentenyloxyethyl methacrylate. The compatibility with, the wettability and the adhesion were good. On the other hand, since an acrylic acid alkyl ester monomer is not used in the acrylic prepolymer, the production of the acrylic prepolymer does not proceed by living radical polymerization. Therefore, the acrylic emulsions AE-21 to AE-24 are the same as the acrylic prepolymer. It became a mixture with the acrylic monomer which carried out emulsion polymerization, and, for this reason, the acrylic emulsion particle enlarged and the stability deteriorated. Also, the solvent resistance is not far from the practical level.

Claims (3)

It is represented by the following structural formula using 0.020 to 0.400 mol of a polymerization initiator with respect to 1.0 mol of α-methylstyrene dimer.

(Here, R1 represents an alkyl group having 4 to 12 carbon atoms.)
It is represented by the following structural formula in the presence of an acrylic prepolymer obtained by bulk polymerization of an acrylic monomer containing an alkyl acrylate ester.

(Where X represents a hydrogen atom or a methyl group, Y represents the following chemical structure

Or the following chemical structure

(Where R2 is a hydrogen atom (H) or the following chemical structure

Represents. ). )
A method for producing an acrylic emulsion comprising emulsion polymerization of an acrylic monomer containing one or more vinyl monomers. The method for producing an acrylic emulsion according to claim 1, wherein a water-soluble organic azo polymerization initiator is used as the polymerization initiator, and an anionic reactive emulsifier having an allyl group in the molecule is used as the emulsifier. The acrylic monomer to be emulsion polymerized has the following structural formula

The acrylic emulsion according to claim 1 or 2, comprising dicyclopentenyloxyethyl methacrylate.