JP3557031B2 - Polyorganosiloxane-containing composite particles and method for producing the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a composite particle of an organic polymer particle and a polyorganosiloxane particle, and more particularly, to a polyorganosiloxane having a structure in which the surface of the organic polymer particle is coated with the polyorganosiloxane particle. Containing composite particles.
[0002]
[Prior art]
Polyorganosiloxane has excellent heat resistance, cold resistance, water resistance, chemical resistance, and weather resistance, and is widely used as a coating agent, a thermoplastic resin, an impact strength modifier for a thermoplastic resin, and the like.
[0003]
However, when polyorganosiloxane is used as a complex with various organic polymers, the compatibility is low, and simply blending does not achieve the complexation. It is not used at present.
[0004]
As a composite particle of a polyorganosiloxane and an organic polymer to solve such a problem, Japanese Patent Application Laid-Open No. 62-280210 discloses a composite particle in which a core composed of a polyorganosiloxane is surrounded by a shell of an acrylate rubber. Have been. Further, Japanese Patent Application Laid-Open No. 4-258636 discloses a method for obtaining a composite particle in which a polyorganosiloxane is composited by advancing a condensation reaction of an organosiloxane in the presence of an organic polymer particle. .
[0005]
However, the composite particles disclosed in JP-A-62-280210 can be obtained by polymerizing a monomer for an acrylate rubber in the presence of polyorganosiloxane particles. , And the excellent properties inherent in polyorganosiloxane are not exhibited. In the method disclosed in JP-A-4-258636, the organosiloxane absorbed in the organic polymer particles does not undergo a condensation reaction, and the organosiloxane not absorbed in the organic polymer particles is used as polyorganosiloxane particles as single particles. And it is difficult to obtain the desired composite particles.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a composite particle with an organic polymer which can effectively utilize the excellent properties of polyorganosiloxane, and a method for producing the same.
[0007]
[Means for Solving the Problems]
The present invention relates to polyorganosiloxane-containing composite particles having a structure in which the surface of organic polymer particles is coated with polyorganosiloxane particles.
[0008]
Further, the present invention provides an aqueous dispersion in which organic polymer particles having a charge on the surface are dispersed, and an aqueous dispersion in which polyorganosiloxane particles having a charge having the opposite sign to the surface charge of the organic polymer particles are dispersed. The present invention relates to a method for producing a polyorganosiloxane-containing composite particle having a structure in which a surface of an organic polymer particle is coated with a polyorganosiloxane particle, which is characterized by mixing with a dispersion.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The organic polymer particles having a charge on the surface constituting the polyorganosiloxane-containing composite particles of the present invention are not particularly limited, and may be selected according to the properties required for the finally obtained polyorganosiloxane-containing composite particles. Any monomer may be used as long as various monomers are selected and polymerized.
[0010]
Specific examples of the monomer include styrene, p-methylstyrene, o-methylstyrene, p-chlorostyrene, o-chlorostyrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene, α- Styrene monomers such as methylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, acrylic acid Acrylic ester monomers such as dodecyl, dodecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether MER; Vinegar Vinyl, vinyl carboxylate monomers of vinyl butyrate, ethylene, propylene, olefin monomers such as isobutylene; butadiene, isoprene, may be mentioned diene monomers and the like of dimethyl butadiene and the like. These monomers can be used alone or in combination of two or more.
[0011]
The method for producing the aqueous dispersion of the organic polymer particles having a charge on the surface used for obtaining the polyorganosiloxane-containing composite particles of the present invention is not particularly limited. For example, an ethylenically unsaturated compound having an ionic group may be used. A method of using a monomer for part or all of a monomer component subjected to polymerization, a soap-free emulsion polymerization method using an ionic polymerization initiator, an emulsion polymerization method using an ionic emulsifier, and the like, Among these, an emulsion polymerization method using an ionic emulsifier is preferred.
[0012]
Examples of the ethylenically unsaturated monomer having an ionic group include a carboxyl group-containing monomer, a sulfo group-containing monomer, and a phosphate group-containing monomer as those having an anionic group. . These anionic group-containing monomers can be used alone or in combination of two or more.
[0013]
Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, monoalkyl maleate, monoalkyl itaconate, and the like.
[0014]
Examples of the sulfo group-containing monomer include styrenesulfonic acid, acryloyloxyalkylsulfonic acid, methacryloyloxyalkylsulfonic acid, acrylamidoalkylsulfonic acid, and methacrylamidoalkylsulfonic acid.
[0015]
Examples of the phosphoric acid group-containing monomer include 2-acryloyloxyethyl phosphoric acid, 2-methacryloyloxyethyl phosphoric acid, 2-acryloyloxyethoxyethyl phosphoric acid, and 2-methacryloyloxyethoxyethyl phosphoric acid. .
[0016]
By neutralizing a copolymer obtained from these anionic group-containing monomers with an appropriate alkali, it is possible to impart a charge to the surface of particles made of the copolymer. Incidentally, a monomer having a salt of these anionic groups may be copolymerized.
[0017]
On the other hand, examples of the ethylenically unsaturated monomer containing a cationic group include an ethylenically unsaturated monomer having a primary amine, a secondary amine, a tertiary amine, a quaternary ammonium salt and the like. can do. These cationic group-containing monomers can be used alone or in combination of two or more.
[0018]
By neutralizing a copolymer obtained from these cationic group-containing monomers with a suitable acid such as hydrochloric acid or acetic acid, it is possible to introduce electric charge to the surface of particles made of the copolymer. it can. In addition, you may copolymerize the monomer containing these salts of a cationic group.
[0019]
Examples of the ionic polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, and anionic polymerizations such as azobis (isobutyronitrile sulfonate) and 4,4'-azobis (4-cyanovaleric acid). Initiator, 2,2'-azobis (amidinopropane) dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'- Cationic polymerization initiators such as azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride and 2,2'-azobisisobutylamide dihydrate can be exemplified.
[0020]
As the ionic emulsifier, any of an anionic emulsifier, a cationic emulsifier, and an amphoteric ionic emulsifier may be used. If desired, a nonionic emulsifier may be used in combination with these ionic emulsifiers.
[0021]
The composite particles having a structure in which the surface of the organic polymer particles of the present invention is coated with polyorganosiloxane particles have surface charges of the organic polymer particles and the polyorganosiloxane particles, each of which is a charge caused by an ionic emulsifier. Preferably, there is.
[0022]
Specific examples of anionic emulsifiers include fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, sulfates of aliphatic amines and aliphatic amides, fatty alcohol phosphates, and sulfonates of dibasic fatty acid esters. Examples thereof include salts, fatty acid amide sulfonates, alkyl allyl sulfonates, and naphthalene sulfonates of formalin condensate.
[0023]
Specific examples of the cationic emulsifier include aliphatic amine salts, quaternary ammonium salts, alkylpyridinium salts and the like, and specific examples of the amphoteric emulsifier include alkylbetaine and the like.
[0024]
The polyorganosiloxane-based particles having a charge of the opposite sign to the surface charge of the organic polymer particles constituting the polyorganosiloxane-containing composite particles of the present invention are polyorganosiloxane-only particles, or polyorganosiloxane-only particles as seed particles. Polyorganosiloxane-containing particles obtained by polymerizing various ethylenically unsaturated monomers may be used.
[0025]
The polyorganosiloxane single particles can be obtained as an aqueous dispersion by a method described in, for example, US Pat. Nos. 2,891,920 and 3,294,725. In the present invention, by using an ionic emulsifier having a charge opposite to the surface charge of the organic polymer particles, for example, when the surface charge of the organic polymer is positive, the organosiloxane and the polyorgano A method of shear-mixing a mixed solution containing a siloxane crosslinking agent and a polyorganosiloxane graft-crosslinking agent with water using, for example, a homogenizer or the like in the presence of a sulfonic acid-based liquid emulsifier such as alkylbenzenesulfonic acid or alkylsulfonic acid. To produce an aqueous dispersion of polyorganosiloxane single particles.
[0026]
Examples of the organosiloxane include cyclic organosiloxanes having three or more membered rings, and those having a three to six membered ring are preferably used. Specific examples of preferred cyclic organosiloxanes include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, and octaphenylcyclo. Examples thereof include tetrasiloxanes, which may be used alone or in combination of two or more.
[0027]
The amount of the cyclic organosiloxane used is preferably 60% by weight, more preferably 70% by weight or more in the polyorganosiloxane rubber.
[0028]
As the crosslinking agent for the polyorganosiloxane, a trifunctional or tetrafunctional silane-based crosslinking agent, that is, a silane compound having three or four alkoxy groups is used, and specific examples thereof include trimethoxymethylsilane and trimethoxymethylsilane. Examples thereof include ethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetrabutoxysilane. As the crosslinking agent for the polyorganosiloxane, a tetrafunctional one is preferred, and among the tetrafunctional crosslinking agents, tetraethoxysilane is particularly preferred.
[0029]
The amount of the crosslinking agent for polyorganosiloxane used is preferably 0 to 30% by weight, more preferably 0 to 10% by weight in the polyorganosiloxane. The use of the polyorganosiloxane crosslinking agent in an amount exceeding 30% by weight does not contribute to the formation of a further crosslinked structure.
[0030]
As a grafting agent for polyorganosiloxane, the alkoxysilane moiety is involved in the polymerization and is incorporated into the polyorganosiloxane rubber, but does not react at this time and subsequently reacts with the ethylenically unsaturated monomer in the presence of the polyorganosiloxane particles. A silane compound having a functional group that reacts upon polymerization of a monomer is used. As a specific example, a compound capable of forming a unit represented by the following formulas 1-1 to 1-4 is used.
[0031]
^{_{CH 2 = CR 2 -COO- (CH}} ) p -SiR 1 n O (3-n) / 2 1-1
^{_{CH 2 = CH-SiR 1 n}} O (3-n) / 2 1-2
^{_{CH 2 = CR 2 -C 6 H}} 4 SiR 1 n O (3-n) / 2 1-3
^{_{HS- (CH) p -SiR 1 n}} O (3-n) / 2 1-4
(In each formula, R ¹ represents a methyl group, an ethyl group, a propyl group, or a phenyl group, R ² represents a hydrogen atom or a methyl group, n represents an integer of 0 to 2, and p represents an integer of 0 to 6, respectively.)
[0032]
Among them, (meth) acryloyloxysilane capable of forming a unit of the formula 1-1 has a high grafting efficiency, and thus can form an effective graft chain. Note that methacryloyloxysilane is particularly preferable as a unit forming the unit of the formula 1-1.
[0033]
Specific examples of methacryloyloxysilane include β-metallyloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyl Oxypropyldiethoxymethylsilane, γ-methacryloyloxypropylethoxydiethylsilane, δ-methacryloyloxybutyldiethoxymethylsilane and the like, among which γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxy Silane can be mentioned as a more preferable one.
[0034]
Examples of the unit capable of forming the unit of the formula 1-2 include vinyltrimethoxysilane and vinylmethyldimethoxysilane. Examples of the unit capable of forming the unit of the formula 1-3 include 4-vinylphenyldimethoxymethylsilane, Examples of vinylphenyltrimethoxysilane and the like, which can form the unit of the formula 1-4 include γ-mercaptopropyldimethoxymethylsilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyldiethoxyethylsilane and the like. it can.
[0035]
The amount of the grafting agent for polyorganosiloxane used is 0 to 10% by weight, preferably 0 to 5% by weight in the polyorganosiloxane.
[0036]
When obtaining the polyorganosiloxane-containing particles, the ethylenically unsaturated monomer polymerized with the polyorganosiloxane-only particles as seed particles is not particularly limited, and the finally obtained polyorganosiloxane-containing composite particles are required. Various monomers may be selected and polymerized according to the characteristics.
[0037]
Specific examples of the monomer include styrene, p-methylstyrene, o-methylstyrene, p-chlorostyrene, o-chlorostyrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene, α- Styrene monomers such as methylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, acrylic acid Acrylic ester monomers such as dodecyl, dodecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether MER; Vinegar Vinyl, vinyl carboxylate monomers of vinyl butyrate, ethylene, propylene, olefin monomers such as isobutylene; butadiene, isoprene, may be mentioned Puren, dimethyl butadiene and the like and diene monomers and the like. These monomers can be used alone or in combination of two or more.
[0038]
The polyorganosiloxane-containing composite particles of the present invention are obtained by stirring and mixing an aqueous dispersion of organic polymer particles having a charge on the surface and an aqueous dispersion of polyorganosiloxane particles having a charge of the opposite sign. be able to. In order to reduce the hetero-aggregation rate when stirring and mixing aqueous dispersions of polymers having mutually different charges, a nonionic emulsifier is added to the surface of the organic polymer particles and / or polyorganosiloxane particles before mixing. It is preferable to adsorb it on the top.
[0039]
The nonionic emulsifier used here is not particularly limited, and specific examples thereof include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, dialkylphenoxy poly (ethyleneoxy) ethanol, polyvinyl alcohol, polyacrylic acid, and alkyl cellulose. Can be mentioned.
[0040]
The particle diameter (a) of the organic polymer particles constituting the polyorganosiloxane-containing composite particles and the particle diameter (b) of the polyorganosiloxane particles constituting the composite particles containing polyorganosiloxane according to the present invention correspond to the particle diameter of the organic polymer. There is no particular limitation as long as is within the range that can be covered.
[0041]
The polyorganosiloxane-containing composite particles of the present invention have a structure in which the surface of an organic polymer is coated with polyorganosiloxane-based particles. The body can also be graft polymerized.
[0042]
【Example】
Hereinafter, the present invention will be described with reference to examples.
In the description, “parts” indicates parts by weight. The various physical properties are measured by the following methods.
Solid concentration: determined by drying the latex at 170 ° C. for 30 minutes.
Particle size distribution, weight average particle size: Measured by a dynamic light scattering method (ELS800, manufactured by Otsuka Electronics Co., Ltd., temperature: 25 ° C., scattering angle: 90 °) using a latex diluted with water as a sample liquid.
[0043]
Reference Example 1 Production of Positively Charged Polymer Particle Dispersion (C-1) 190 parts of distilled water, dodecyltrimethylammonium chloride 0 in a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet. 0.4 part, 100 parts of butyl acrylate and 0.4 part of cumene hydroperoxide were charged and heated to 40 ° C. under a nitrogen stream. Next, a mixed solution of 0.001 part of iron (II) sulfate, 0.003 part of sodium ethylenediaminetetraacetate, 0.24 part of Rongalite salt and 10 parts of distilled water was added to start radical polymerization. After the end of the heat generation, the temperature in the system was maintained at 40 ° C. for 2 hours to complete the polymerization, thereby obtaining a polymer particle dispersion (hereinafter referred to as C-1).
The solid content concentration of C-1 was 33.1%, the particle size distribution showed a single peak, and the weight average particle size was 259 nm. The ζ potential was 25 mV.
[0044]
[Reference Example 2] Production of polymer particle dispersion liquid (A-1) having negative charge In addition to using 0.4 parts of dodecyltrimethylammonium chloride in Reference Example 1, 0.4 parts of sodium dodecylbenzenesulfonate was used. A polymer particle dispersion (hereinafter referred to as A-1) was obtained under the same operation and conditions as in Reference Example 1.
The solid content concentration of A-1 was 33.2%, the particle size distribution showed a single peak, and the weight average particle size was 190 nm. The ζ potential was −32 mV.
[0045]
[Reference Example 3] Production of negatively charged organosiloxane-based particle dispersion (S-1) 0.5 parts of γ-methacryloxypropyldimethoxymethylsilane and 99.5 parts of octamethylcyclotetrasiloxane were mixed, and a siloxane mixture was obtained. 100 parts were obtained. A mixed solution of 1 part of sodium dodecylbenzenesulfonate and 300 parts of distilled water was added thereto, and the mixture was stirred at 10,000 rpm for 2 minutes with a homomixer, and then passed twice through a homogenizer at a pressure of 300 kg / cm ² to obtain a stable premix. An organosiloxane latex was obtained.
[0046]
On the other hand, a separable flask equipped with a stirring blade, a condenser, and a thermocouple was charged with 14 parts of dodecylbenzenesulfonic acid and 100 parts of distilled water, the temperature was raised to 85 ° C., and the premixed organosiloxane latex was added for 4 hours. After the dropwise addition, the temperature was maintained for 1 hour after the completion of the dropwise addition, followed by cooling. Next, the reaction product was maintained at room temperature for 24 hours, and then neutralized with a 5% aqueous sodium hydroxide solution to obtain an organosiloxane-based particle dispersion (hereinafter, referred to as S-1).
The solid content concentration of S-1 was 18.1%, the particle size distribution showed a single peak, and the weight average particle size was 30 nm. The ζ potential was −61 mV.
[0047]
[Example 1]
21.1 parts (solid content: 7.0 parts) of C-1 which is a polymer particle dispersion having a positive charge obtained in Reference Example 1 was collected, and polyoxyethylene nonyl phenyl ether (nonionic emulsifier) was collected. Cloud point 74 ° C; 0.35 parts of Kao Corporation, trade name Emulgen 911) was added, and the mixture was stirred at room temperature for 1 hour. The mixture thus obtained was added to 16.6 parts of S-1 (solid content: 3.0 parts) obtained in Reference Example 3, stirred at room temperature for 30 minutes, and then heated to 85 ° C. for further 1 The mixture was stirred for 1 hour and further for 1 hour. No solids were separated during the series of operations, and a uniform latex was obtained.
[0048]
The solid content of this latex was 27.3%. In addition, the particle size distribution showed a single peak, no small particles remained, and the weight average particle size was 310 nm. The solid content of the latex was reduced to 0.001%, and the dried product was observed with a transmission electron microscope. As a result, the organic polymer was coated with polyorganosiloxane-based particles, and the polyorganosiloxane-containing composite particles were in the shape of confetti. It was confirmed.
[0049]
[Comparative Example 1]
Instead of using 21.1 parts of C-1 in the examples, 21.1 parts (solid content of 7.0 parts) of A-1 which is the polymer particle dispersion having negative charge obtained in Reference Example 2 was used, Otherwise in the same manner as in Example 1, a uniform latex was obtained.
[0050]
The solid content of this latex was 27.3%. The particle size distribution had peaks at around 30 nm and around 190 nm, respectively. When the solid content of the latex was reduced to 0.001% and the dried product was observed with a transmission electron microscope, it was confirmed that the organic polymer particles and the polyorganosiloxane particles were present separately.
[0051]
【The invention's effect】
The polyorganosiloxane-containing composite particles of the present invention are excellent as thermoplastic resin coating agents having excellent heat resistance, cold resistance, water resistance, chemical resistance, and weather resistance, and modifiers for thermoplastic resins.

Claims (4)

Polyorganosiloxane-containing composite particles having a structure in which the surface of organic polymer particles is coated with polyorganosiloxane particles. An aqueous dispersion in which organic polymer particles having a charge on the surface are dispersed, and an aqueous dispersion in which polyorganosiloxane particles having a charge having the opposite sign to the surface charge of the organic polymer particles are mixed. The method for producing polyorganosiloxane-containing composite particles according to claim 1, wherein: The method for producing polyorganosiloxane-containing composite particles according to claim 2, wherein the surface charges of the organic polymer particles and the polyorganosiloxane particles are respectively charges caused by the ionic emulsifier. The polyorgano according to claim 2, wherein the nonionic emulsifier is adsorbed on the surface of the organic polymer particles and / or the polyorganosiloxane particles before mixing the aqueous dispersion of the organic polymer particles and the polyorganosiloxane particles. A method for producing siloxane-containing composite particles.