JP2006265352A - Compounded polymer particle and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a compounded polymer particles dispersed with titanium oxide in a simple method. <P>SOLUTION: This method for producing the compounded polymer particles comprises a process of mixing 100 pts.wt. vinyl-based monomer containing the vinyl-based monomer having carboxy group, phosphoric acid group or both of them with 10-120 pt.wt. polyalkoxy titanate oligomer expressed by formula (1) [wherein, (n) is 3-15 integer; and R is an alkyl] and a polymerization initiator to obtain a monomer mixture, and a process of obtaining the compounded polymer particles dispersed with titanium oxide derived from the polyalkoxy titanate oligomer by performing an aqueous suspension polymerization of the vinyl-based monomer in the monomer composition in the presence of a suspension stabilizer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to composite polymer particles and a method for producing the same. More specifically, the present invention relates to composite polymer particles in which inorganic particles made of titanium oxide are dispersed in a fine size, which can be obtained by a simple method, and a method for producing the same.

  Conventionally, composite polymer particles containing a powder of a metal or an oxide thereof have been used as, for example, an electrophotographic toner.

  For example, JP-A-8-53568 (Patent Document 1) discloses metal oxide particles such as zinc oxide, and 1 to 50% by weight of carboxylic acid, sulfonic acid, sulfate ester, phosphorous based on the metal oxide particles. At least one dispersant selected from acid esters, phosphonic acids, and salts thereof is dispersed in a monomer or a mixture of a monomer and a solvent, and the dispersed particle size of the metal oxide particles is 0. A method for producing composite resin particles containing metal oxide particles by preparing a dispersion liquid of .mu.m or less, adding the dispersion liquid to an aqueous medium, and subjecting the monomer to suspension polymerization or emulsion polymerization is shown.

  Japanese Patent Application Laid-Open No. 8-21649 (Patent Document 2) discloses a chemically insoluble alkyl group and an alkoxy group present on the surface of a magnetic powder as reactive radicals to a water-insoluble monomer in which the magnetic powder is dispersed. For electrophotography containing magnetic powder by suspension polymerization of a monomer dispersion coated with magnetic powder by adding a silane compound having a group (hydrophobic compound) in an aqueous medium with a predetermined particle size A method for producing toner is described.

  Furthermore, in Japanese Patent Application Laid-Open No. 2003-192791 (Patent Document 3), a metal such as titanium or zirconia is chemically bonded (coupled) to a resin particle using a metal silane condensate (hydrophobic compound). Composite resin particles contained therein are described.

  The proposal of the publication mentioned above is to make a metal or its oxide particles, which are originally hydrophilic, oleophilic by a dispersant or by coating the surface of the particles with a hydrophobic compound or coupling with a hydrophobic compound. Is dispersed in water-insoluble monomers and encapsulated in resin particles under suspension or emulsion polymerization.

JP-A-8-53568 JP-A-8-21649 JP 2003-192791 A

  In any of the above technologies, the metal oxide particles are not sufficiently oleophilic, so that they are not sufficiently dispersed in the monomer, and it is difficult to efficiently encapsulate them in the resin particles. Furthermore, there has been a problem that the process is complicated, for example, it is necessary to treat the surface of the metal oxide particles in advance. In addition, in order to make the metal oxides lipophilic, a separate chemical is required, and there is a problem that costs are increased.

  The metal silane condensate can be obtained by using a metal alkoxide having extremely high hydrolyzability such as titanium alkoxide, aluminum alkoxide, zirconium alkoxide, etc., and using such metal alkoxide, the metal oxide can be stably formed into particles. It was not easy to obtain resin particles dispersed in a shape.

  The inventors of the present invention have intensively studied to solve the above-mentioned problems, and as a result, an oligomer-derived titanium oxide is dispersed by subjecting a vinyl monomer to aqueous suspension polymerization in the presence of a specific polyalkoxy titanate oligomer. The present inventors have found that the obtained composite polymer particles can be easily obtained, and have reached the present invention.

  Thus, according to the present invention, 100 parts by weight of a vinyl monomer containing a vinyl monomer having a carboxyl group, a phosphate group, or both, and the following formula (1)

(In the formula, n is an integer of 3 to 15, and R is an alkyl group)
And a step of mixing a polymerization initiator with 10 to 120 parts by weight of a polyalkoxy titanate oligomer represented by the following, and the vinyl monomer in the monomer composition in the presence of a suspension stabilizer. A method for producing composite polymer particles comprising a step of obtaining composite polymer particles in which titanium oxide derived from the polyalkoxytitanate oligomer is dispersed by aqueous suspension polymerization is provided.
Moreover, according to this invention, the composite polymer particle obtained by the said method is provided.

  According to the production method of the present invention, a polyoxyalkoxytitanate oligomer is dispersed in a vinyl monomer, and the resulting polymer particles contain (or include) titanium oxide by a simple method comprising suspension polymerization. ) Can be produced with high efficiency.

  According to the present invention, the carboxyl group or phosphate group in the vinyl-based monomer is chemically bonded to the alkoxide group of the polyalkoxy titanate oligomer by substitution reaction, so that the hydrolyzability of the polyalkoxy titanate oligomer can be controlled, The polyalkoxy titanate oligomer can be easily dispersed stably in the aqueous medium.

  The vinyl monomer that can be used in the present invention is not particularly limited as long as it has a carboxyl group, a phosphate group, or both. Specifically, acrylic acid, methacrylic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl acid phosphate and the like can be mentioned. Among these, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl succinic acid, and 2-methacryloyloxyethyl acid phosphate are preferable. These vinyl monomers can be used alone or in combination of two or more.

  Furthermore, you may use other vinylic monomers other than the above in the range which does not inhibit the effect of this invention. Examples of other vinyl monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, p- Styrene such as chlorostyrene and 3,4-dichlorostyrene and derivatives thereof,

Vinyl esters such as vinyl acetate, vinyl propionate and vinyl butyrate,
Methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, 2-acrylate Chlorethyl, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate , Stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethyl methacrylate α- methylene aliphatic monocarboxylic acid esters such as aminoethyl,

Acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate,
Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone,
Examples thereof include N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, and vinyl naphthalene salts. These other vinyl monomers can be used alone or in combination of two or more.
Among other vinyl monomers, inexpensive styrene, methyl methacrylate and the like are preferable.

  Moreover, it is also possible to obtain crosslinked polymer particles by using a monomer having two or more functional groups such as ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and divinylbenzene.

The other vinyl monomer is preferably used in an amount of 0 to 1500 parts by weight, preferably 100 to 1000 parts by weight, based on 100 parts by weight of the vinyl monomer having a carboxyl group, a phosphate group, or both. Is more preferable.
Next, a polyalkoxytitanate oligomer having a structural formula as shown below can be used.

  In said formula, n is an integer of 3-15, Preferably it is an integer of 3-10. Here, since the low molecular weight alkoxy titanate having n of 2 or less has a very high functional group hydrolysis, it is difficult to stably exist in the monomer droplets, and it is stably suspended in an aqueous medium during suspension polymerization. It is not preferable because it cannot be done. On the other hand, when n is 16 or more, the viscosity of alkoxy titanate is high, and it is not preferable because it is difficult to stably suspend in an aqueous medium during suspension polymerization.

  R is an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms. Specific examples include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, and tert-butyl. R may be the same or different.

  Specific examples of the polyalkoxy titanate oligomer include oligomers such as polymethoxy titanate, polyethoxy titanate, polypropoxy titanate, and polybutoxy titanate. Among these, polypropoxy titanate oligomers and polybutoxy titanate oligomers which are moderately hydrolyzable and have good phase separation from the resin are preferable. Particularly preferred are polymethoxy titanate oligomers and polybutoxy titanate oligomers with n = 3-10.

  As the polyalkoxy titanate oligomer, a mixture of n, R, or different ones may be used.

  The addition amount of the polyalkoxy titanate oligomer is preferably 10 to 120 parts by weight, more preferably 10 to 100 parts by weight with respect to 100 parts by weight of the vinyl monomer. When the amount is less than 10 parts by weight, the effect obtained by incorporating titanium oxide into the polymer particles is poor, which is not preferable. When the amount is more than 120 parts by weight, the composite polymer particles cannot be stably obtained, which is not preferable.

  Moreover, it is preferable that the usage-amount of a vinyl-type monomer is 2-20 times mole with respect to the mole number of a polyalkoxy titanate oligomer from another viewpoint, and it is still more preferable that it is 2-10 times mole. More specifically, for example, in the case where the vinyl monomer is 2-methacryloyloxyethyl succinic acid (molecular weight 230) with respect to 1 g (molecular weight 2069) of n = 10 polybutoxy titanate oligomer in the above formula (1). The amount of the monomer used is preferably 0.22 to 2.2 g, more preferably 0.22 to 1.1 g. When the amount is less than 2 times the number of moles of the polyalkoxy titanate oligomer, the effect of controlling the hydrolyzability of the polyalkoxy titanate oligomer is small, and it is difficult to disperse in the aqueous medium. Even if it is more than 20-fold mol, no further effect is observed, which is not preferable.

  A hydrolyzable alkoxy metal compound other than titanium may be added to the vinyl monomer. Specific examples include polyalkoxysilane oligomers and zirconium alkoxides.

  A polymerization initiator is used for the polymerization of the vinyl monomer. Examples of the polymerization initiator include oil-soluble peroxide polymerization initiators and azo polymerization initiators that are usually used in aqueous suspension polymerization. Specific examples include benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide, t-butyl. Peroxide polymerization initiators such as hydroperoxide and diisopropylbenzene hydroperoxide, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2 '-Azobis (2,3-dimethylbutyronitrile), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,3,3-trimethylbutyronitrile), 2, 2'-azobis (2-isopropylbuty Nitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile, (2-carbamoylazo) isobutyronitrile, 4, Examples thereof include azo initiators such as 4′-azobis (4-cyanovaleric acid) and dimethyl-2,2′-azobisisobutyrate.

  Among these, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide, lauroyl peroxide, and the like are in terms of the decomposition rate of the polymerization initiator. Is preferable.

  The polymerization initiator is preferably used in an amount of 0.01 to 10 parts by weight, more preferably 0.1 to 5.0 parts by weight, based on 100 parts by weight of the total vinyl monomer. If the polymerization initiator is less than 0.01 parts by weight, it is difficult to achieve the polymerization initiation function, which is not preferable. Moreover, when using exceeding 10 weight part, since it is uneconomical in cost, it is unpreferable.

  The vinyl monomer, polyalkoxy titanate oligomer, polymerization initiator, and other components are mixed by a known method to form a monomer composition.

  Next, examples of the aqueous medium for aqueous suspension polymerization of the monomer composition include water or a mixed medium of water and a water-soluble solvent such as alcohol. The amount of the aqueous medium used is usually 100 to 1000 parts by weight with respect to 100 parts by weight in total of the vinyl monomer and polyalkoxy titanate oligomer in order to stabilize the suspended particles.

  In order to suppress the generation of emulsified particles in an aqueous system, water-soluble polymerization inhibitors such as nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, citric acid, and polyphenols may be used. Good.

  Furthermore, you may add a suspension stabilizer to an aqueous medium as needed. Examples of the suspension stabilizer include phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate, pyrophosphates such as calcium pyrophosphate, magnesium pyrophosphate, aluminum pyrophosphate and zinc pyrophosphate, calcium carbonate Examples thereof include poorly water-soluble inorganic compounds such as magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, and colloidal silica. Among these, tricalcium phosphate, magnesium pyrophosphate, calcium pyrophosphate, and colloidal silica produced by the metathesis method are preferable because polymer particles can be stably obtained.

  Suspension stabilizers may be used singly or in combination of two or more. However, in consideration of the particle diameter of the obtained polymer particles and dispersion stability during polymerization, the type of the suspension stabilizer and the amount used are appropriately determined. Used by adjusting. Usually, the addition amount of the suspension stabilizer is 0.5 to 15 parts by weight with respect to 100 parts by weight of the polymerizable vinyl monomer.

  The suspension stabilizer can be used in combination with a surfactant such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

  Examples of the anionic surfactant include fatty acid oils such as sodium oleate and castor oil potassium, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfone. Acid salts, alkane sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene alkyl sulfates and the like.

  Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxy Examples include ethylene-oxypropylene block polymers.

  Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.

  Examples of the zwitterionic surfactant include lauryl dimethylamine oxide and phosphate ester or phosphite ester surfactants.

Surfactants may be used singly or in combination of two or more, but in consideration of the particle diameter of the resulting polymer particles and dispersion stability during polymerization, the selection of the type and the amount used are appropriately adjusted. Used. Usually, the addition amount of the surfactant is 0.001 to 0.1 parts by weight with respect to 100 parts by weight of the aqueous medium.
The monomer composition is added to the aqueous medium thus prepared, and aqueous suspension polymerization is performed.

  As a method for dispersing the monomer composition, for example, a method in which the monomer composition is directly added to an aqueous medium and dispersed in the aqueous medium as monomer droplets by a stirring force of a propeller blade or the like, a high shear force composed of a rotor and a stator is used. Examples thereof include a method of dispersing using a homomixer that is a dispersing machine to be used, an ultrasonic dispersing machine, or the like. Among these, the monomer composition is pressed into an aqueous medium through a high-pressure type disperser or MPG (microporous glass) porous film using collision of monomer droplets such as microfluidizer and nanomizer and collision force to the machine wall. It is preferable to disperse by the above method because the particle diameters can be made more uniform.

  Next, suspension polymerization is initiated by heating the aqueous medium in which the monomer composition is dispersed as spherical monomer droplets. During the polymerization reaction, it is preferable to stir the aqueous medium. For example, the stirring may be performed so gently that the droplets of the monomer and the particles after polymerization are prevented from being settled.

  In the suspension polymerization, the polymerization temperature is preferably about 30 to 100 ° C, more preferably about 40 to 80 ° C. The time for maintaining this polymerization temperature is preferably about 0.1 to 20 hours.

  The polyalkoxy titanate oligomer is condensed and converted to titanium oxide during aqueous suspension polymerization, and is finely and uniformly dispersed inside the polymer particles. As a result, the composite polymer particles of the present invention can be obtained.

  Furthermore, when a polyalkoxy titanate oligomer remains after the polymerization reaction, the condensation may be promoted by adding an acid catalyst or a base catalyst to the aqueous medium.

  As the acid catalyst and the base catalyst, hydrochloric acid, sulfuric acid, ammonia, sodium hydroxide, potassium hydroxide, ammonium nitrate and the like can be used. When the production container is made of steel or stainless steel, basic sodium hydroxide, ammonia, or the like is preferable from the viewpoint of corrosion or the like. The addition amount of the catalyst is preferably 0.01 to 30 parts by weight, more preferably 1 to 15 parts by weight with respect to 100 parts by weight of the polyalkoxy titanate oligomer.

  After suspension polymerization and, if necessary, a condensation step with an acid catalyst or a basic catalyst, the suspension stabilizer is decomposed with hydrochloric acid or the like, and the inorganic composite polymer particles are suction filtered, centrifuged, dehydrated, centrifuged, and added. The hydrous cake may be separated by a method such as pressure dehydration, and the obtained hydrous cake may be washed with water and dried to isolate the composite polymer particles.

  The size and shape of the composite polymer particles of the present invention are not particularly limited. According to the above method, for example, particles having an average particle diameter of 1 to 100 μm can be obtained. The average particle diameter can be adjusted by adjusting the mixing conditions of the monomer composition and water, the addition amount of a suspension stabilizer, a surfactant and the like, the stirring conditions of the agitator, and the dispersion conditions.

  According to the present invention, composite polymer particles in which, for example, titanium oxide having a particle diameter of 0.1 μm or less is dispersed inside the particles can be obtained. In addition, since titanium oxide is finely dispersed inside the particles, it has high transparency and high light transmission properties. Therefore, LCD spacers, surface modifiers for silver salt films, film modifiers for magnetic tapes, thermal paper running stabilizers, etc., in the electronics industry, paints, inks, adhesives, etc. for rheology control agents, matting agents, etc. Used in chemical fields, medical fields such as antigen-antibody reaction test particles, cosmetics fields such as slip agents and extender pigments, general industrial fields such as paper, dental materials, anti-blocking agents, light diffusing agents, and resin modifiers. Is possible.

EXAMPLES Next, although an Example further demonstrates this invention in detail, this invention is not restrained by these description.
The average particle diameter of the composite polymer particles, the content of the inorganic particles, and the dispersion state of the inorganic particles in the composite polymer particles were measured by the following methods.

(Measurement method of average particle diameter)
The electrolyte solution is filled in pores having a pore diameter of 50 to 280 μm, the volume is obtained from the change in conductivity of the electrolyte solution when the particles pass through the electrolyte solution, and the average particle diameter is calculated. Specifically, the measured average particle diameter is a volume average particle diameter measured with a Coulter Multisizer II manufactured by Beckman Coulter. In the measurement, calibration is performed using an aperture suitable for the particle diameter of the particle to be measured according to REFERENCE MANUAL FOR THE COULTER MULTISIZER (1987) issued by Coulter Electronics Limited.

  Specifically, 0.1 g of particles and 10 ml of 0.1% nonionic surfactant solution were put into a commercially available glass test tube, mixed for 2 seconds with a touch mixer TOUCHMIXER MT-31 manufactured by Yamato Scientific Co., Ltd., and then tested. The tube was pre-dispersed for 10 seconds using a commercially available ultrasonic cleaner, ULTRASONIC CLEANER VS-150, manufactured by VervoCrea, and this was filled with ISOTON 2 (manufactured by Beckman Coulter, Inc .: electrolyte for measurement) equipped with the main body. In a beaker, drop gently with a dropper while stirring gently, and adjust the reading of the densitometer on the main screen to about 10%. Next, the aperture size, Current, Gain, and Polarity are input to the Multisizer 2 body according to REFERENCE MANUAL FOR THE MULTILIZER MULTISIZER (1987) issued by Coulter Electronics Limited, and measured manually. During the measurement, the beaker is stirred gently to the extent that bubbles do not enter, and the measurement is terminated when 100,000 particles are measured.

(Inorganic particle content)
Using TG / DTA6200 (manufactured by Seiko Instruments Inc.), about 0.02 g of the sample was weighed in an aluminum oven container (manufactured by Seiko Instruments Inc.) and set in an autosampler of TG / DTA6200. The temperature was raised at 5 ° C./min, and a differential thermal analysis was performed from room temperature (about 25 ° C.) to 500 ° C. in an air atmosphere. From the graph (vertical axis: temperature, horizontal axis: time) obtained by the above operation, the remaining weight is defined as the amount of inorganic particles contained in the particles at 500 ° C.

(Dispersion state of inorganic particles in composite polymer particles)
The composite polymer particles obtained by the present invention were embedded in an epoxy resin, an ultrathin section was prepared, and the cross section was observed with a TEM (transmission electron microscope).

Example 1
A dispersion medium in which 5 g of magnesium pyrophosphate by metathesis method is mixed with 200 g of water as a suspension stabilizer is placed in a 500 ml separable flask, 0.04 g of sodium lauryl sulfate as a surfactant, and sub-aqueous as a water-soluble polymerization inhibitor. An aqueous medium was prepared by dissolving 0.02 g of sodium nitrate in the dispersion medium.

Separately, as a monofunctional vinyl monomer, 35 g of methyl methacrylate, 5 g of 2-methacryloyloxyethyl succinic acid, polyalkoxy titanate oligomer (Organic titanate manufactured by Nippon Soda Co., Ltd., trade name B-10: R in the above structural formula is C ₄ A monomer composition was prepared by uniformly dissolving H ₉ , n = 10, molecular weight 2069) 10 g, and 2,2′-azobis (2,4-dimethylvaleronitrile) 0.25 g as a polymerization initiator.

The number of moles of the polyalkoxy titanate oligomer was 4.8 × 10 ⁻³ , and the number of moles of 2-methacryloyloxyethyl succinic acid was 2.17 × 10 ⁻² .

  This monomer composition was added to the aqueous medium, and stirred at 8000 rpm for about 10 seconds with a homomixer (manufactured by IKA: ULTRA TURRAX T-25) to finely disperse the monomer composition. A separable flask, a thermometer and a reflux condenser were attached to the separable flask, and after replacing with nitrogen, it was placed in a constant temperature water bath (water bath) at 60 ° C. Stirring is continued in the separable flask at a stirring speed of 200 rpm, and the polymerizable vinyl monomer is subjected to suspension polymerization for 10 hours after the temperature of the dispersion medium added with the monomer composition in the separable flask reaches 60 ° C. And then the reaction was continued at 80 ° C. for 8 hours.

  Next, the separable flask is taken out from the constant temperature water bath, the reaction liquid in the separable flask is cooled to room temperature while stirring the separable flask, and hydrochloric acid is added until the pH of the slurry becomes about 2 to obtain a suspension stabilizer. Was decomposed to obtain composite polymer particles.

  The obtained particles were suction filtered with a Buchner funnel using filter paper, washed with 5 L of ion exchange water to remove the suspension stabilizer, and dried to take out the target particles.

  The obtained composite polymer particles had an average particle diameter of 5.8 μm and an inorganic content of 7.8% by weight. Moreover, the TEM photograph of this particle | grain is shown to FIG. FIG. 2 is an enlarged photograph of FIG. 1 and 2, it was observed that the inorganic particles were uniformly dispersed inside the composite polymer particles, and the particle diameter was smaller than 0.1 μm.

Example 2
A composite polymer was prepared in the same manner as in Example 1, except that 25 g of methyl methacrylate, 20 g of polyalkoxy titanate oligomer, and 0.12 g of 2,2′-azobis (2,4-dimethylvaleronitrile) were changed. Particles were obtained.

The number of moles of the polyalkoxy titanate oligomer was 9.67 × 10 ⁻³ , and the number of moles of 2-methacryloyloxyethyl succinic acid was 2.17 × 10 ⁻² .

  The average particle diameter of the obtained composite polymer particles was 16.3 μm, and the content of inorganic particles was 18.7%. Further, by TEM observation of the particles, it was observed that the inorganic particles were uniformly dispersed inside the particles as in Example 1, and the particle diameter was smaller than 0.1 μm.

Example 3
The same method as in Example 1 except that organic titanate (trade name B-4 manufactured by Nippon Soda Co., Ltd .: R is C ₄ H ₉ , n = 7, molecular weight 906) was used as the polyalkoxy titanate oligomer. Thus, composite polymer particles were obtained.

The number of moles of the polyalkoxy titanate oligomer was 5.52 × 10 ⁻³ , and the number of moles of 2-methacryloyloxyethyl succinic acid was 2.17 × 10 ⁻² .

  The average particle diameter of the obtained inorganic composite polymer particles was 6.4 μm, and the content of inorganic particles was 7.1%. Further, by TEM observation of the particles, it was observed that the inorganic particles were uniformly dispersed inside the particles as in Example 1, and the particle diameter was smaller than 0.1 μm.

Example 4
Composite polymer particles were obtained in the same manner as in Example 1 except that 2-methacryloyloxyethyl acid phosphate (molecular weight 186) was used instead of 2-methacryloyloxyethyl succinic acid.

The number of moles of the polyalkoxy titanate oligomer was 5.52 × 10 ⁻³ , and the number of moles of 2-methacryloyloxyethyl acid phosphate was 2.69 × 10 ⁻² .

  The average particle diameter of the obtained inorganic composite polymer particles was 28.9 μm, and the content of inorganic particles was 7.9%. Further, by TEM observation of the particles, it was observed that the inorganic particles were uniformly dispersed inside the particles as in Example 1, and the particle diameter was smaller than 0.1 μm.

Comparative Example 1
Except that tetrapropoxy titanate was used instead of polyalkoxy titanate oligomer, the trial production of the particles was examined in the same manner as in Example 1. However, the metathesis method was performed using 200 g of the monomer composition as a suspension stabilizer for 200 g of water. At the stage of suspending in a dispersion medium mixed with 5 g of magnesium pyrophosphate, an oily product was generated by hydrolysis of tetrapropoxy titanate, and oil droplets could not be dispersed, making fine particles impossible. .

Comparative Example 2
In Example 1, microparticulation was examined under the same conditions except that 2-methacryloyloxyethyl succinic acid was not used. However, pyrophosphoric acid by metathesis method was used with the monomer mixture as a suspension stabilizer for 200 g of water. At the stage of suspending in a dispersion medium mixed with 5 g of magnesium, an oily product was produced by hydrolysis of tetrapropoxytitanate, and the oil droplets could not be dispersed, making it impossible to make fine particles.

Comparative Example 3
A dispersion medium in which 5 g of magnesium pyrophosphate by metathesis method is mixed with 200 g of water as a suspension stabilizer is placed in a 500 ml separable flask, 0.04 g of sodium lauryl sulfate as a surfactant, and sub-aqueous as a water-soluble polymerization inhibitor. An aqueous medium was prepared by dissolving 0.02 g of sodium nitrate in the dispersion medium.

  Separately, 35 g of methyl methacrylate as monofunctional vinyl monomer, 5 g of ethylene glycol dimethacrylate, 10 g of titanium dioxide hydrophobized on the surface (particle diameter 0.3 μm), 2,2′-azobis (2 , 4-dimethylvaleronitrile), a monomer composition prepared by uniformly dissolving 0.25 g.

This monomer composition was subjected to suspension polymerization in the same manner as in Example 1 to obtain composite polymer particles.
The resulting composite polymer particles had an average particle diameter of 7.8 μm and an inorganic particle content of 20% by weight.

Example 5
3 weights of composite polymer particles obtained in Example 1 and Comparative Example 3 and commercially available acrylic spherical fine particles not containing inorganic particles (manufactured by Sekisui Plastics Co., Ltd .: trade name Techpolymer MBX-8, average particle size 8 μm) Parts were added to 100 parts by weight of methyl methacrylate resin (MG-5 manufactured by Sumitomo Chemical Co., Ltd.), kneaded, and then supplied to an extruder to obtain master pellets.

  The obtained pellets were supplied to an injection molding machine and molded to obtain a molded product having a length of 100 mm, a width of 50 mm, and a thickness of 2 mm. The total light transmittance and haze of the obtained molded product were measured with a turbidimeter (trade name NDH200, standard JIS K7316) manufactured by Nippon Denshoku. The obtained results are shown in Table 1.

  From Table 1, it can be seen that the composite polymer particles of the present invention have high light permeability because the inorganic particles are dispersed in the polymer particles. Therefore, if it is dispersed in a transparent resin, light diffusibility can be imparted to the resin.

  The composite polymer particles of the present invention are used in the electronic industry fields such as LCD spacers, surface modifiers for silver salt films, film modifiers for magnetic tapes, thermal paper running stabilizers, paints such as rheology control agents and matting agents.・ Chemical field such as ink and adhesive, medical field such as antigen-antibody reaction test particles, cosmetic field such as slip agent and extender pigment, paper, dental material, anti-blocking agent, light diffusing agent, resin modifier, etc. It can be used in general industrial fields.

2 is a TEM photograph of composite polymer particles of Example 1. FIG. It is an enlarged photograph of FIG.

Claims (4)

100 parts by weight of a vinyl monomer containing a vinyl monomer having a carboxyl group, a phosphate group or both, and the following formula (1)
(In the formula, n is an integer of 3 to 15, and R is an alkyl group)
And a step of mixing a polymerization initiator with 10 to 120 parts by weight of a polyalkoxy titanate oligomer represented by the following, and the vinyl monomer in the monomer composition in the presence of a suspension stabilizer. And a step of obtaining composite polymer particles in which titanium oxide derived from the polyalkoxytitanate oligomer is dispersed by aqueous suspension polymerization.   The method for producing composite polymer particles according to claim 1, wherein n is an integer of 3 to 10, and R is a C1 to C10 alkyl group.   3. The method for producing composite polymer particles according to claim 1, wherein the vinyl monomer is used in an amount of 2 to 10 moles relative to the polyalkoxy titanate oligomer. Composite polymer particles obtained by the method according to claim 1.