FR2503168A1 - POLYMERIZABLE COMPOSITIONS CONTAINING MINERAL CHARGE AND METHOD USING THEM TO PRODUCE POLYMER PARTICLES - Google Patents

Abstract

THE INVENTION RELATES TO POLYMERISABLE COMPOSITIONS CONTAINING A MINERAL FILLER AND A PROCESS USING IT TO PRODUCE POLYMER PARTICLES: THE COMPOSITIONS CONTAIN 10 TO 80 BY WEIGHT OF A MINERAL FILLER, 0.1 TO 5 BY WEIGHT RELATED TO THE FILLER MINERAL OF A COUPLING AGENT OF SILANE TYPE, 0.01 TO 2 BY WEIGHT WITH RESPECT TO THE MINERAL CHARGE OF A COUPLING ACCELERATOR WITH A SILANE AND, IF DESIRED, 5 TO 50 BY WEIGHT RELATED TO THE VINYL MONOMER OF A VINYL POLYMER SOLUBLE IN VINYL MONOMER AT LEAST AT HOT: THE INTRODUCTION OF SUCH A COMPOSITION, HAVING A VISCOSITY AT 20C OF 100 TO 10000CP, IN WATER CONTAINING A SUSPENSION STABILIZER, AND HEATING OF THE MIXTURE TO PERFORM SUSPENSION POLYMERIZATION OF VINYL MONOMER, ALLOWS POLYMER PARTICLES HAVING A NARROW GRAIN SIZE DISTRIBUTION.

Description

The present invention relates to compositions

  polymerizable materials containing inorganic filler and processes

  reading to produce polymer particles.

  More particularly, the invention relates to

  polymerizable positions containing a mineral filler having a

  low viscosity (for example 100-10,000 cP at 200C) which is

  by uniform dispersion of mineral fillers in vinyl monomers, radically polymerizable, and a process for producing polymer particles having a narrow grain size distribution (e.g., 0.1-100 μm) by use

of these compositions.

  It is known that rigidity, dimensional stability, electrical properties, ease of incineration etc.,

  polymers can be improved by the addition of significant amounts of

  of mineral fillers to polymers. The addition of these mineral fillers is generally carried out by mixing the mineral fillers with the molten polymers by using cylinders, kneaders, extruders, and the like. However, according to such methods, it is difficult to prepare

  a uniform mixture when the amount of mineral filler increases.

  If mixing is prolonged to improve dispersion

  of the mineral charge in the polymer, there is a deterioration

the polymer.

  To eliminate the aforementioned defect, a process has been proposed in which mineral fillers are added to a polymerizable vinyl monomer by radical mechanism, such as the

  styrene, and the monomer is then polymerized to prepare a

  polymer in which the mineral fillers are dispersed uniformly. However, this process has various defects. For example in the case where the mineral filler content is higher

  at 10% by weight, it is difficult to prepare a single dispersion

  form because the inorganic filler tends to precipitate and generally the composition obtained has a bold or clay character. In addition, it is virtually impossible to transfer the composition into a

  polymerization reactor and polymerize it.

  For example, styrene-based polymer particles are produced by suspension polymerization of styrene monomer in the presence of polymerization initiators and suspension stabilizers. The particle size distribution of the polymer particles prepared by suspension polymerization is broad

  even though the degree of agitation, the temperature and the duration of poly-

  and the mode of addition of styrene monomer and polymerization initiators are suitably selected. Polymer particles having such large grain size distributions have the following disadvantages: (1) When extruding the polymer particles it is very common for the polymer particles having a small size to separate from the particles of the polymer particles. polymer having a large size in the feed hopper, the feed section of an extruder or the screw section of an extruder. This causes a significant undesirable variation in the hourly amount of

extruded molten polymer.

  (2) When expansive beads are expanded in a mold

  prepared by impregnation with a swelling agent of

  polymer during or after the suspension polymerization,

  the differences in the degree of expansion of the polymer beads

  produce molded articles of unequal weight or cause polymer beads to have irregular cooling periods

during molding.

  In general, expandable beads having a low

  size have a weak expansion force but can be fast-

  heated and cooled, while when grain size increases the force of expansion increases as

  necessary for heating and cooling.

  The optimum size of the expandable beads has an influence on the cooling time, the degree of expansion, the thickness of the mold article and the like. The molded articles are divided into general purpose articles having a thickness of 5 to 10 mm and blocks having a thickness of 100 mm or more. In the

  production of blocks, it is necessary to use expanded pearls

  sibles having a higher grain size. However, it is usual to sift the expandable beads to separate them into several categories of different grain sizes even in the two main application areas above $ as a function of

  the intended use of the final molded article.

  Expandable beads prepared by suspension polymerization of monomeric styrene containing a mineral filler have a wider grain size distribution than the

  pearls containing no mineral fillers as a result of the approval

  charge in styrene.

  The object of the invention is to solve the problems which the dispersion of the mineral fillers in the vinyl monomers in a proportion of 10 to% by weight with respect to the weight of the vinyl monomer and of the mineral filler poses; and a method for producing polymer particles having a narrow grain size distribution, on a regular basis, to solve the problems of casting a

  extended distribution of grain size.

  As a result of important research aimed at solving the problems encountered when combining 10% or more of one or more inorganic fillers with one or more vinyl monomers, the Applicant has discovered that a coupling treatment with a silane of the mineral filler (s) of a vinyl monomer (containing substantially no water) allows an easy dispersion of the mineral filler (s) in the monomer (s) vinyl (s) and at the same time reduces the viscosity of the dispersion

obtained.

  In addition, the introduction of one or more vinyl polymers soluble in one or more vinyl monomers further increases the stability of the dispersion of mineral fillers.

in the mixture obtained.

  The invention therefore provides (1) a polymerizable composition containing a mineral filler comprising 90 to 20% by weight of one or more vinyl monomers and 10 to 80% by weight of one or more mineral fillers dispersed in the monomer (s) (s) vinyl (s), which additionally contains one or more silane coupling agents and one or more silane coupling accelerators 0.1 to 5% by weight and 0.01 to 2, respectively % by weight, relative to the weight of the mineral filler (s). Hereinafter to simplify, the singular is generally used to designate such components

single or multiple.

  (2) A process for producing polymer particles containing 10 to 80% by weight of a mineral filler which comprises mixing a mineral filler, a silane coupling agent and a coupling accelerator with a silane in a vinyl monomer to prepare a mixed solution, subjecting the mixed solution to a preliminary bulk polymerization in the presence of a

  polymerization initiator until 5 to 45% by weight of the mono-

  vinyl mother are polymerized to adjust the viscosity (at 200C) of the reaction system between 100 and 10 000 cP, introduce the preliminary mass polymerization solution in water containing a suspension stabilizer, and then heat the mixture to perform the polymerization in suspension of the unreacted vinyl monomer. (3) A process for producing polymer particles containing 10 80% by weight of a mineral filler comprising mixing a mineral filler, a silane coupling agent and a coupling accelerator with a silane in a vinyl monomer to prepare a mixed solution, a preliminary bulk polymerization of the mixed solution in the presence of a

  polymerization initiator until 5 to 45% by weight of the mono-

  vinyl polymer are polymerized to adjust the viscosity (at 200C) of the reaction system between 100 and 10 000 cP, the introduction of the preliminary bulk polymerization solution continuously into

  a mass polymerization reactor and the completion of the poly-

  mass melting of the unreacted vinyl monomer in the

  mass polymerization reactor.

  (4) A polymerizable composition containing a mineral filler comprising 90 to 20% by weight of a vinyl monomer and 80% by weight of a mineral filler dispersed in the vinyl monomer which further contains a silane coupling agent and a coupling accelerator with a silane at the rate of 0.1 to 5% by weight and 0.01 to 2% by weight, respectively, relative to the weight

  of the mineral filler and a vinyl polymer soluble in the mono-

  vinyl (at least hot) mother at 5 to 50% by weight per

  relative to the weight of the vinyl monomer.

  (5) A process for producing polymer particles containing 10 to 80% by weight of a mineral filler comprising mixing a mineral filler, a silane coupling agent and a coupling accelerator with a silane in a monomer

  to prepare a mixed solution, the addition of a poly-

  vinyl monomer which is soluble in the vinyl monomer (at least on heat) to the mixed solution to prepare a solution having

  a viscosity at 20C of 10 to 10,000 cP, the introduction of the

  in water containing a suspension stabilizer and then heating the resulting solution to effect polymerization

in bulk of the vinyl monomer.

  The invention will now be described in detail. The term "vinyl monomer" as used herein refers to vinyl monomers which are liquid at ordinary temperature and which can be polymerized by radical mechanism. A suitable example of a vinyl monomer is a compound having a -CH-CH 2 radical. Typical examples of such vinyl monomers include styrene-based monomers such as styrene, α-methylstyrene and chlorostyrene, esters of acrylic acid and a lower alcohol containing 1 to 8 carbon atoms, such as methyl acrylate and n-butyl acrylate, methyl methacrylate, acrylonitrile, vinyl acetate, maleic anhydride and vinyl chloride. We can

  use these monomers alone or in combination.

  The term "inorganic filler" refers here to the fine powders of inorganic compounds having an average grain size of from 0.1 to 100 μm. Suitable examples of such inorganic compounds include metal oxides such as silica, alumina, silica and the like. iron oxide, zinc oxide and magnesium oxide, metal hydroxides such as aluminum hydroxide, magnesium hydroxide and iron hydroxide, metals such as aluminum and iron asbestos, glass, calcium carbonate, magnesium carbonate, sodium sulphate, kieselguhr and glass fibers. Of these mineral compounds, metal hydroxides are particularly preferred because they greatly reduce the viscosity of the dispersion obtained. They can be used singly or in combination. com-

mutual boring.

  A silane coupling agent of general use can be used in the invention. For example, in addition to the compounds represented by the general formula: ## STR1 ## where R represents a monovalent hydrocarbon radical or a halogenated hydrocarbon radical preferably having 1 to 12 carbon atoms, for example an alkyl radical such as methyl or ethyl, propyl, octyl, and decyl, an alkenyl radical, a vinyl radical, an aryl radical, for example a phenyl, benzyl or tolyl radical, and a haloalkyl radical, for example a chloropropyl, trifluoro-3,3-propyl or bromophenyl radical; X represents a hydrolyzable radical such as a formyloxy, acetoxy, propoxy radical, an oxime function or an alkoxy radical preferably having 1 to 6 carbon atoms, for example a methoxy, ethoxy or propoxy radical, and n is equal to O 1 or 2), the alkoxy-containing silanes represented by the general formulas (II) to (V) OR2 ## STR2 ##

OR 2

  OR2 CH = CR1-C-O-A-Si-R3 (III) 2;

O OR2

  OR 2 CH -CH-CH 2 O-A-Si-R (IV) OR 2 OR 2 H2N-A-NH-A-Si-R (V) OR where R is H or CH 3, R 2 is a straight or branched alkyl radical containing 4 atoms of carbon or less, R represents OR2o R2 has the same definition as above, a straight or branched alkyl radical containing 4 or less carbon atoms or a phenyl radical, and A represents a straight or lower alkylene radical;

  branched having 6 carbon aromas or less.

  Suitable examples are silanes containing no

  no double bonds such as: tetramethoxysilane, tetra-

  ethoxysilane, tetrapropoxysilane, tetrabutoxysilane,

  methyltrimethoxysilane, methyltriethoxysilane, methyltri-

  propoxysilane, methyltributoxysilane, ethyltriethoxysilane,

  ethyltributoxysilane, dimethyldipropoxysilane, dimethyl-

  dibutoxysilane, diphenyldimethoxysilane, phenyltrimethoxy-

  silane, diphenyldiethoxysilane, trimethylmethoxysilane,

  trimethylethoxysilane, trimethylpropoxysilane, trimethyl-

  butoxysilane, and tripropoxymonochloropropylsilane; vinyls

  silanes, such as vinyltrimethoxysilane, vinyltrimethoxysilane, vinyltripropoxysilane, methacryloxymethyltrimethoxysilane,

  methacryloxymethyltriethoxysilane, methacryloxymethyltri

  poxysilane, methacryloxyethyltrimethoxysilane, methacryloxy-

  ethyltriethoxysilane, methacryloxyethyltripropoxysilane,

  methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane

  silane, methacryloxypropyltripropoxysilane, acryloxymethyl-

  trimethoxysilane, acryloxymethyltriethoxysilane, acryloxymethyl-

  tripropoxysilane, acryloxyethyltrimethoxysilane, acryloxyethyl-

  triethoxysilane, acryloxyethyltripropoxysilane, acryloxypropyl-

  trimethoxysilane, acryloxypropyltrimethoxysilane, acryloxypropyl-

  triethoxysilane, and acryloxypropyltripropoxysilane; N-amino

  méthylaminométhyltriméthoxysilane; γ-glycidopropylmethyldipro-

  poxysilane; and p-glycidoxyethylethyldiethoxysilane.

  These silanes can be used singly or in combination

his mutual.

  The silane coupling accelerators that can be used in the invention include carboxylic acid salts such as dibutyltin dilaurate, dioctyltin dilaurate, stannous acetate, stannous octenoate, lead naphthenate zinc octenoate, iron 2-ethylhexanoate and cobalt naphthenate; esters of titanic acid such as tetrabutyl titanate, tetranonyl titanate and bis (acetylacetonitrile) diisopropyl titanate; organometallic compounds such as chelating compounds; and bases

  minerals such as ethylamine, hexylamine and dibutylamine.

  Examples of vinyl polymers which are soluble in the previously described at least hot vinyl monomers include polystyrene, polymethyl methacrylate, methyl polyacrylate, polyacrylonitrile, a copolymer of acrylonitrile and styrene, a styrene copolymer and of

  butadiene and a copolymer of styrene, acrylonitrile and butadiene

  diene. The expression "soluble in the vinyl monomer at least by heating" indicates here that the vinyl polymer is still soluble in the vinyl monomer at the temperature at which the bulk polymerization is carried out and of course it covers the case where the vinyl polymer is soluble in vinyl monomer

at the ordinary temperature.

  In the polymerizable composition containing a mineral filler of the invention, the inorganic filler is dispersed in the vinyl monomer or in a mixture of the vinyl monomers

  and the vinyl polymer at 10 to 80% of the weight of the

  obtained. In addition, the polymerizable composition containing a mineral filler contains the silane coupling agent and the silane coupling accelerator, respectively 0.1 to 5% by weight and 0.01 to 2% by weight. weight, relative to the weight of the inorganic filler, and at the same time it contains the vinylic polymer soluble in the vinyl monomer (at least by heating) at 5 to 50% by weight relative to the weight of the vinyl monomer. To prepare the polymerizable inorganic filler composition of the invention, by bulk polymerization of the vinyl monomer, the inorganic filler is added to make up 10 to 80%, preferably 20 to 70%, of the weight of the monomer. composition, the silane coupling agent is added to make up 0.1 to 5% and preferably 0.5 to 3% by weight of the inorganic filler and the coupling accelerator is added with silane so that it constitutes 0.01 to 2% by weight

mineral charge.

  When the proportion of the inorganic filler in the composition is less than 10% by weight, the mechanical strength and the dimensional stability of the polymer are not sufficiently improved. When the proportion of the inorganic filler in the composition exceeds 80% by weight, it is difficult to uniformly disperse the mineral filler in the vinyl monomer and to

  the higher the viscosity of the composition obtained and its

pulation becomes difficult.

  The silane coupling agent is added in an amount of from 0.1 to 5% and preferably from 0.5 to 37% by weight relative to the weight of the inorganic filler. When the amount of the silane coupling agent added is less than 0.1% by weight, it is difficult to uniformly disperse the inorganic filler and furthermore it can not be expected to decrease the viscosity of the resulting composition. Even when the silane coupling agent is added in amounts greater than 5% by weight, the effect of improving the dispersibility or reducing the viscosity can not be increased. Moreover, it is economically disadvantageous to use a significant amount of such

  expensive silane coupling agents.

  The coupling accelerator is used with a silane in a proportion of from 0.01 to 2% by weight relative to the weight of the inorganic filler. When the amount of silane coupling accelerator added is less than 0.01% by weight, the coupling reaction with a silane is slow and not practical. Even when the silane coupling accelerator is added in amounts greater than 2% by weight, an increased acceleration effect of the coupling reaction with a silane can not be expected and the addition of these amounts can not be expected. of a coupling accelerator with a silane is disadvantageous

from an economic point of view.

  To prepare the composition of the invention, the vinyl monomer and the inorganic filler are first mixed together and the silane coupling agent and the coupling agent are added with a silane and then the mixture is stirred for 5 hours.

mixture obtained.

  Although the exact reason for which the composition of the invention to which the silane coupling agent has been

  combined with a low viscosity compared to a com-

  taking the inorganic filler and the vinyl monomer and not containing silane coupling agent is not elucidated, however, it is assumed that this reason is the following When the mineral filler is simply dispersed in the vinyl monomer, such as mineral filler has a poor affinity to the vinyl monomer, the particles of the inorganic filler agglomerate with each other, which increases the apparent volume occupied by the inorganic filler in the composition. On the other hand, when the silane coupling agent is added to the composition, it combines with the mineral filler so that

  this has an affinity for the vinyl monomer.

  In addition, the agglutination of the filler particles is limited, the filler is dispersed uniformly in the vinyl monomer and the increase in the apparent volume occupied by the mineral filler in the composition is less important. So, when you add the same amount of mineral filler to a composition that does not contain

  the silane coupling agent, the viscosity of the

  is greater than that of a similar composition containing

the silane coupling agent.

  In addition, since the average grain size of the mineral filler is reduced, an aggregation easily occurs.

  and the viscosity of the resulting composition rises.

  Although the mechanism of the modification of the inorganic filler by the silane coupling agent is not elucidated, it seems that when using as coupling agent of the type

  silane a silane containing an alkoxy radical and a metal hydroxide

  As the inorganic filler, a dealcoholization reaction occurs which chemically unites the coupling agent and the inorganic filler. To accelerate the coupling reaction and quickly prepare a uniform dispersion, the accelerator is added.

coupling with a silane.

  To the polymerizable composition containing a mineral filler which is subjected to the subsequent preliminary mass polymerization, a radical polymerization initiator is added.

  during the preparation of the composition or after its preparation.

  The radical polymerization initiators that can be used include organic peroxides such as

  benzoyl peroxide, lauryl peroxide, methyl peroxide,

  ethylcetone, dicumyl peroxide, tert-butyl di (peroxybenzoate) -2,5 hexyne-3 and p-oxybenzoate, as well as azo compounds such as azobisisobutyronitrile and dimethyl azodiisobutylate. The amount of polymerization initiator used is between 0.1 and 5% by weight, preferably between 0.5 and

  1% by weight relative to the weight of the vinyl monomer.

  In addition, if desired, one can add to the composi-

  an antioxidant, a thermal stabilizer, an ultraviolet absorber, a plasticizer and a soluble rubbery material

in the vinyl monomer.

  We submit the composition that we combined

  the polymerization initiator to a preliminary mass polymerization

  in which 5 to 45% by weight and preferably 20 to 35%. by weight of the vinyl monomer are polymerized to prepare a bulk polymerization solution of the vinyl monomer whose viscosity at 200C is adjusted to 100 to 10,000 cP and

  preferably between 200 and 5000 cP. The poly-

  preliminary mass melting at temperatures of 60 to 130 ° C

  and at pressures of 1 to 2 bar in a closed reactor.

  The polymerization solution is then introduced into

  preliminary mass in water containing a stabilizer of

  and the mixture is heated to polymerize the unreacted vinyl monomer in suspension, or else the preliminary bulk polymerization solution whose viscosity has been adjusted to between 100 and 10,000 cP in a bulk polymerization reactor is continuously introduced. larger (i.e. 2 to 10 times larger) where mass polymerization is complete. The polymer thus prepared is sprayed to produce the desired polymer particles. The preliminary bulk polymerization carried out before the suspension polymerization or the subsequent mass polymerization further prevents the precipitation of the inorganic filler in the reaction system and facilitates the transport of the solution.

  preliminary mass polymerization in the poly-

  in suspension or in bulk, and the polymerization in

  pension or mass polymerization on a large scale.

  When the vinyl monomer is styrene, the acry.

  hitrile or methyl methacrylate, the polymerization is carried out

  preliminary mass under the following conditions:

  polymerization temperature 70 to 110 ° C and polymerization time 1.5 to hours, preferably 2 to 5 hours. In this preliminary mass polymerization, 5 to 45% by weight and preferably 20 to 35% by weight

  Styrene weights undergo preliminary polymerization.

  When the viscosity at 200C of the polymer solution

  preliminary mass density reaches 100 to 10 000 cP, it is possible to

  continuously transfer the mass polymerization solution pre-

  in a large scale mass polymerization reactor where it is subjected to mass polymerization at 150 to 2000 ° C for 5 to 10 hours (see Japanese Patent 50961/80); otherwise the preliminary mass polymerization solution can be introduced into an aqueous medium containing a suspension stabilizer with stirring to prepare a suspension and carries out suspension polymerization for 2 to 10 hours between 60 and C, preferably for 4 to 6 hours between 80 and 130'C for

  complete the polymerization of the unreacted styrene.

  The polymerizable solution having a viscosity of 100 to 10,000 cP can also be prepared at 20 ° C by addition of a vinyl polymer as previously described in the bulk polymerization. According to this process, the polymerizable composition is prepared so that the amount of the inorganic filler is from 10 to 80% by weight, and preferably from 20 to 70% by weight relative to the polymerizable composition, the amount of the agent silane type of coupling is from 0.1 to 5% by weight and preferably from 1 to 3% by weight relative to the mineral filler, the amount of the coupling accelerator with a silane is from 0.01 to 27 by weight relative to the inorganic filler, the amount of the vinyl monomer is 10 to 85% by weight, preferably 15 to 60% by weight, based on the polymerizable composition and the amount of the vinyl polymer is 5 to 50% by weight and preferably from 10 to 30% by weight relative to the vinyl monomer. It is preferred to prepare the polymerizable composition so that it has a

  viscosity of 100 to 10,000 cP and preferably 200 to 5,000 cP.

  When the amount of vinyl polymer added is less than 5% by weight, the effect of improving the storage stability of the dispersion is poor. On the other hand, when it is greater than 50% by weight, the viscosity of the composition is undesirably increased to a value too high.

  which makes it difficult to transport the polymerization reactor

and polymerization. To prepare the polymerizable composition above, all

  firstly the vinyl monomer and the inorganic filler, the silane coupling agent and the coupling accelerator are added with a silane, the system is stirred uniformly, the vinyl polymer is added and the system is again uniformly agitated. ,

  if it is necessary, heating between 60 and 1300C.

  Otherwise, to prepare the polymeric composition,

  risible, dissolve the vinyl polymer beforehand in the mono-

  vinyl mother, add the mineral filler and mix, then add the silane coupling agent and the coupling accelerator

with a silane and mix.

  In the case of a prepared polymerizable composition

  as above, the radical polymerization initiator can be added

  required for polymerization during or after preparation

  composition. If necessary, or if desired, the polymerizable composition may contain an antioxidant, a thermal stabilizer, an ultraviolet absorber, a plasticizer

  and a rubbery material soluble in the vinyl monomer.

  The polymerizable composition is also particularly

  It is useful for producing polymer particles having a narrow grain size distribution by suspension polymerization. To carry out this suspension polymerization, the polymerizable composition which has been combined with

  the above polymerization initiator in an aqueous medium containing

  a suspension stabilizer with stirring to prepare a suspension and the suspension is heated to a higher temperature.

  at the decomposition temperature of the polymerization initiator.

  When the vinyl monomer is styrene, acrylonitrile, methyl methacrylate or the like, the polymerization is carried out in suspension for 2 to 10 hours at 60 to 140 ° C, preferably for 2 to 4 hours at 80 to 130 ° C. to complete the polymerization

  unreacted vinyl monomer.

  The inorganic filler is dispersed uniformly in the polymer particles prepared by preliminary mass polymerization or suspension polymerization of the composition of the invention. Suspension stabilizers that can be added in the suspension polymerization include organic suspension stabilizers, for example polyvinyl alcohol, polyvinylpyrrolidone, gelatin, carboxymethylcellulose and the like.

  hydroxyalkylcellulose, and mineral suspension stabilizers

  such as the calcium or magnesium salts of phosphoric acid and carbonic acid. When using a

  mineral suspension stabilizer, for example trihydric phosphate

  Calcium, it is preferred to use sodium dodecylbenzenesulphonate

  which is an anionic surfactant in combination as a stabilizer

reading auxiliary.

  The amount of suspension stabilizer used is 0.1 to 3% by weight of the reaction solution and the amount of the auxiliary stabilizer used is 0.002 to 0.05% by weight of the water.

  The volume ratio (phase ratio) of the solu-

  Reaction to water in the suspension polymerization is from 0.5 to 2.0 and preferably from 1.0 to 1.5. When the phase ratio is at least 0.5, the reactor charge can be reduced

  is economical and reduces the water content of

  obtained and facilitates their drying. On the other hand, when the ratio of the phases is greater than 2.0, the agitation becomes difficult.

  As the progress of the polymerization progresses.

  Molded articles obtained by injection molding, extrusion molding or calendering of the inorganic filler-containing polymer particles according to the invention exhibit excellent rigidity and dimensional stability. The molding conditions are described, for example, in Injection Extrusion and Blowing of Expandable Polystyrene, Brit. Plastics, p. 172, April

(1962).

  Although the invention has previously been disclosed with respect to a process for producing polymer particles not containing blowing agent, particles can be prepared.

  of polymer containing a blowing agent by carrying out the polymerization

  above suspension and then impregnating

  obtained with a swelling agent or otherwise

  of the blowing agent in the reaction system during mass polymerization or suspension polymerization and then

  performing the polymerization. In general, the introduction of the agent -

  swelling in the reaction system during the polymerization in

  suspension is convenient from the point of view of the stages of polymerization.

  However, when the expandable particles obtained have a small grain size, it is preferred to impregnate the particles of the blowing agent after suspension polymerization taking into account that the blowing agent can be dispersed during sieving.

and the storage of particles.

  The blowing agents that can be used include

  aliphatic hydrocarbons such as propane, n-butane,

  isobutane, n-pentane, neopentane, and hexane, hydro-

  alicyclic carbides such as cyclobutane, and cyclopentane and halogenated hydrocarbons such as methyl chloride and dichlorodifluoromethane. They can be used singly or in combination. The blowing agent is generally introduced so that the swelling agent content of the particles formed is

  about 5 to 20% based on the weight of the vinyl polymer.

  The styrene-based polymer particles obtained according to the invention contain 45% or more particles included in marketable quality and the size distribution of the

  grain particles is narrow and sieving is easy.

  The invention is illustrated by the following nonlimiting examples in which parts and percentages are

  expressed by weight, unless otherwise indicated.

  The viscosity of the dispersion and the precipitation time of the inorganic filler are measured as follows: Viscosity: The viscosity of the dispersion is determined at 200 ° C with a viscometer (Model B produced by Tokyo Keiki Co., Ltd.); Precipitation time: we transfer to a

  one liter of a dispersion prepared by mixing and stirring

  quickly after stopping the agitation and allow to stand.

  The precipitation time is the time required for 207 by volume of a supernatant liquid to form as a result of the precipitation

mineral charge.

Exemnple 1

  To 100 parts of styrene, 40 parts of

  aluminum oxide having a mean grain size of 17 μm (sold under the brand name of "igilite" by Showa Keikinzoku Co., Ltd.) at 20 ° C with stirring. Phenyltrimethoxysilane (sold under the brand name of "KBM-103" by Shin-Etsu Kagaku Co., Ltd.) and dibutyltin dilaurate are then added at 1.0% and 0.2%, respectively, relative to weight of the aluminum hydroxide and the resulting mixture is stirred at 20 ° C for 15 minutes to prepare a

uniform dispersion.

  The viscosity of the dispersion at 20 C is 5 cP (determined with a model B viscometer produced by Tokyo Keiki

Co., Ltd.).

  Examples 2 and 3 Dispersions are prepared as in Example 1 except that the amount of aluminum hydroxide added is

150 parts or 300 parts.

  The viscosities of the dispersions are 23 cP and

1,075 cP.

  COMPARATIVE EXAMPLES 1-3 Comparative dispersions were prepared as in Examples 1-3 except that phenyltrichloride was not added.

  methoxysilane or dibutyltin dilaurate.

  The appearance and physical properties of these disper-

  comparisons are shown in Table I below

* TABLE I

  Comparative Example Aspect Viscosity (centipoise) 1. Dispersion 12 2 Dispersion 1370 3 Fat> 1 x 105 Examples 4 and 5 Dispersions are prepared as in Example 1

  except that the average grain size of the aluminum hydroxide

minium is 1 μm or 60 μm.

  The viscosities of the dispersions are respectively

of 120 cP and 3.5 cP.

  Comparative Examples 4 and 5 Comparative dispersions are prepared as in Comparative Example 1 except that the average grain size

  aluminum hydroxide is 1 μm or 60 μm.

  The viscosities of the comparative dispersions

in Table II below.

TABLE II

  Comparative Example Viscosity (centipoise) a uniform dispersion is not obtained.

Example 6

  As in Example 2, except that the methaethacryloxypropyltrimethoxysilane (sold under the trademark "KBM503" by Shin-Etsu Kagaku Co., Ltd.) was used instead of phenyltrimethoxysilane, a stable dispersion was prepared.

having a viscosity of 22 cp.

  Examples 7 to 12 and examples: Comparatives 6 to 11

  Compositions consisting of ingredients are prepared

  Table III in the same manner as in Example 1 and the appearance and physical properties

  of each composition. The results are shown in Table III.

Honomer N vinyl test

Example 7

Example 8

Example 9

Example 10

Example 11

  Styrene (100) is methyl methacrylate (100) Compositic mineral filler medium grain size 4 Ig (01ll) 2 (40) i "" (100) 8 A2 (O0) 3 (100) 4 Talc (50) 17 At (OR) 3 (100)

TABLE III

(parties) Coupling agent

Phenyltrimétllthoxy-

silane (0.4)

"(O1,0)

and (1,0) and (0,5)

"(1> 0)

  Accelerator dilaurate of dibutyl- (0> 08) tin

"(0,2)

(0.2)

"(0,1)

(0.2)

Example

  Methyl methacrylate (100) acrylonitrile (100) 4 Mg (OH) 2 (40) e "" (100)

8 A. (OH) 3

4 Talc

17 AL (011) 3

"(100)

  Viscosity (cP) 3 650 Appearance Dispersion and and g '

"8

  - o 1200 (100) (50) (100) t Bold Dispersion and> 1 x 105 3 500 1 830 u Ln 0% o c It

Example 13

  To 100 parts of styrene is added 0.4 part of phenyltrimethoxysilane and 0.08 part of dibutyltin dilaurate.

  and stirring the mixture uniformly at 200C.

  40 parts of aluminum hydroxide having an average grain size of 17 μm are then added and the resulting mixture is stirred at 20 ° C. to obtain a dispersion having a viscosity at 20 ° C.

C of 6 cP.

Example 14

  To the dispersion having a viscosity of 5 cP obtained in Example 1 is added 0.3 part of benzoyl peroxide and 0.2 part of tert-butyl peroxybenzoate, and the

  mixture obtained in an autoclave where it is heated to 80 ° C.

  Preliminary bulk polymerization was conducted at this temperature for 2.5 hours to prepare a bulk polymerization solution of styrene (monomeric styrene plus styrene polymer). The degree of polymerization of styrene in the solution

-l -

  (infrared absorption ratio at 1632 cm and 1,602 cm)

is 21X2%.

  The viscosity at 20 C of the preliminary mass polymerization solution of styrene is 3070 cP. When one liter of the solution is introduced into a test tube and allowed to stand, the precipitation time necessary for the

  volume of the supernatant liquid reaches 20% is 20 hours.

  The preliminary mass polymerization solution of styrene is introduced into 200 parts of water in which 0.6 part of polyvinylpyrrolidone has been dissolved, with stirring at 200 rpm.

  and raising the temperature of the polymerization reactor in suspension.

  from 80 ° C to 1250 ° C in 7 hours. Stirring is continued at 1250C for one hour to complete the suspension polymerization and

  obtain polymer particles.

  The polymer particles thus produced contain

  53% of particles have a grain size of 0.59 to 1 mm, and have an average grain size of 0.81 mm. The aluminum hydroxide content of the particles is 24.9% (theoretical value, 6%).

Example 15

  To the dispersion having a viscosity of 5 cP prepared in Example 1, 0.3 part of benzoyl peroxide is added. By continuously introducing the dispersion at a constant rate into a preliminary polymerization reactor

  whose temperature is set at 850 ° C., the polymer is

  preliminary mass of 40% by weight of styrene. The preliminary mass polymerization solution thus obtained is continuously introduced into a reactor equipped with an agitator where a mass polymerization is carried out at 160 ° C. until 99.2% of the styrene is polymerized. Finally, polymer particles are obtained using an extruder equipped with

a degassing device.

  The aluminum hydroxide content of the

  The polymer particles are 25.3% (theoretical value: 25.6%).

  Examples 16 to 18 To 100 parts of styrene was added 40 parts of aluminum hydroxide (sold under the brand name "Higilight" by Showa Keikinzoku Co., Ltd.) having an average grain size of 17 μm. Phenyltrimethoxysilane (sold under the brand name of "KBM-103" by Shin-Etsu Kagaku is then added

  Co.3 Ltd.) and dibutyltin dilaurate respectively

  1.0% and 0.2%, based on the weight of aluminum hydroxide

  minium. Three of the samples prepared as above at 20 ° C. are then added to polystyrene having a molecular weight average of 150,000 at 10 parts.

  parts or 50 parts with stirring to prepare dispersions.

  The viscosity and the precipitation time are measured.

  each dispersion; the results are shown in Table IV.

  Examples 19 and 20 and Comparative Examples 12 to 16 As in Example 16, dispersions were prepared

  composed of the ingredients shown in Table IV.

  The viscosity and the precipitation time are measured.

  each dispersion; the results are shown in Table IV.

TABLE IV

  Composition (Parts) Styrene AZ (0H) Phenyltri-Dilaurate Polystyrene _____ __ (_) 3 Methoxysilane Dibuty Tain Viscosity (cP)

40,014 0.08 10,120

40 0s4 0.08 25 1 307

40 0.4 0.08 40 7 200

i "13 100

"14,100

"15 100

"16,100

  3.0 0.4 0.3 0) 6 0.08 9 500 o 3 820 600 Despitation time 36)] 410 min hr min min hand 2.5 s min h h Test n Exeminple 16 "t 17

"18

"19

"20

Exempt

  As shown by the results in Table IV, the dispersions of Comparative Examples 12 to 14 have poor storage stability, the dispersion of Comparative Example 16

  has a very high viscosity and is difficult to polymerize and.

  the dispersion of Comparative Example 15 which must be compared

  That of Example 17 has poor storage stability.

Example 21

  To 100 parts of styrene is added 40 parts of aluminum hydroxide (sold under the brand name "Higilite" by Showa Keikinzoku Co., Ltd.) having a mean grain size of 17 μm, with stirring and added phenyltrimethoxysilane (sold under the brand name "KBM-103" by ShinEtsu Kagaku Co., Ltd.) and dibutyltin dilaurate, respectively 1.0% and 0.2% based on the weight of the product. aluminum hydroxide for performing a coupling treatment with a silane of aluminum hydroxide.

  To the styrene solution containing the aluminum hydroxide

  which has undergone the coupling treatment with a silane,

  add 0.3 part of benzoyl peroxide and 0.2 part of peroxygen peroxide

  tert-butyl benzoate for 100 parts of styrene and more parts of polystyrene having a number average of the weight

  molecular weight of 150,000 per 100 parts of styrene and dissolved.

  The dispersion obtained is added to 200 parts of an aqueous solution containing 0.6 part of polyvinylpyrrolidone with stirring.

  at 300 rpm and suspended.

  The temperature of the suspension is raised from 80 ° C. to 7 ° C. continuously for 7 hours and the polymerization is completed.

  styrene by heating the suspension at 125 C for 1 hour.

  The beads thus prepared are washed with water and dried in air. Fifty percent of the beads have an average grain size of 0.85 mm. The aluminum hydroxide content of pearls

  of polymer is 25.3% calculated from the ash content.

  This shows that 99.0% of the added aluminum hydroxide is

  contained in the polymer beads.

031 68

  Examples 22 and 23 The procedure of Example 21 is repeated except that the amount of aluminum hydroxide is 150 parts or 300 parts and the amount of the 0.3% aqueous solution of polyvinylpyrrolidone is 250 parts or

400 parts.

  Fifty-seven of the polymer beads have a mean grain size of 1.07 mm in the first case and 1.23 ma in the second case. The aluminum hydroxide content of the polymer beads is 55.7% (theoretical value: 56.4%) in the first

  case and 70.8% (theoretical value: 72.1%) in the second case.

  Comparative Examples 17 to 19 The procedures of Examples 21 to 23 are repeated except that phenyltrimethoxysilane and dibutyltin dilaurate are not added (respectively comparative examples).

& 19).

  Fifty percent of the polymer beads obtained in Comparative Example 17 had a mean grain size of 2.5 mm and the aluminum hydroxide content was 5.1% (value

theoretical: 25.6%).

  In Comparative Examples 18 and 19, as shown in

  cosity of each dispersion is high, it is impossible to obtain

  a uniform dispersion in the water and the suspension polymerization

sion can not be completed.

  Comparative Examples 20 to 22 The procedure of Examples 21 to 23 is repeated except that the polymerization is carried out without the addition of

  polystyrene (respectively Comparative Examples 20 to 22).

  Fifty percent of the polymer beads obtained had a mean grain size of 0.47 mm in Comparative Example 20, 0.63 mm in Comparative Example 21 and 0.71 mm in Comparative Example 22. The Aluminum hydroxide content was 17.7% (theoretical 28.4%) in Comparative Example 20, 44.8% (theoretical 59.8%) in Comparative Example 21 and 59.2 %

  <theoretical value 74.8%) in Comparative Example 22.

  Comparative Example 23 A suspension polymerization is carried out as

  in Example 16 except that phenyltrimide is not added.

  methoxysilane or dibutyltin dilaurate; 50% of the polymer beads have a mean grain size of 2.15 mm and an aluminum hydroxide content of 1.6%.

(theoretical value: 28.9%).

Example 24

  A suspension polymerization is carried out as in Example 23 except that aluminum hydroxide having a mean grain size of 1 μm is used instead of aluminum hydroxide having an average molecular weight of 1 μm. average size of grains of 17> im; polymer beads are obtained, 50% of which have an average grain size of 1.72 mm and the hydroxide content

  of aluminum is 71.9% (theoretical value: 72.1%).

  Examples 25 and 26 A suspension polymerization was carried out as in Example 23 except that aluminum hydroxide having a mean grain size of 4 μm was used instead of hydroxide. aluminum having an average grain size of 17, u (Example 25) or using ferric oxide having an average grain size of 8 μm instead of hydroxide

  aluminum with an average grain size of 17 μm (eg

  ple 26). The polymer beads obtained in each example have the following properties: Example Average grain size Load content *%; (mm) (%.)

1.63 70.8

26 1.47 69.2

* The theoretical value is 72.1%.

Example 27

  We obtain in the same way as in Example 23,

  except that y-methacryloxypropyltrimethoxy-

  silane instead of phenyltrimethoxysilane, polymer beads of which 50X have a mean grain size of 1.27 mm and whose

  Aluminum hydroxide content is 72.0% (theoretical value: 72.1%).

Example 28

  Polymerization is carried out as in Example 23 except that methyl methacrylate is used instead of styrene, and polymethyl methacrylate having a number average molecular weight of 150 ° C is used.

place of polystyrene.

  The polymer beads thus obtained have 50% average grain size of 0.96 mm and their hydroxide content

of aluminum is 70.9%.

Example 29

  As in Example 21, the system is heated in suspension at 1250 ° C. for one hour and then cooled to 900 ° C. and a mixture of isobutane and n-butane (4/6 by volume) is introduced as swelling agent. The resulting mixture is maintained at this temperature for 5 hours to complete the slurry polymerization and after cooling the polymer beads so obtained are washed with water and air dried to obtain expandable polystyrene beads having a in agent

inflating 6.3%.

  The expandable polystyrene beads have 50% average grain size of 0.88 mm and their hydroxide content

  of aluminum is 23> 5% (theoretical value: 25,3%).

  When the expandable polystyrene beads are immersed in boiling water for 2 minutes, pre-expanded polystyrene beads having a bulk density of 30 g / l are obtained. These pre-expanded polystyrene beads are placed in a mold (200 nm × 200 mm × 50 mm) and molded by heating for 90 seconds with steam at a pressure of 0.8 bar. After 2 minutes of cooling, the article is demolded; it is a good quality expanded element having

a density of 33 g / l.

  Of course, various modifications may be made by those skilled in the art to devices or methods that

  have been described only as non-limitative examples

  without departing from the scope of the invention.

Claims (11)

R E V E N D I C A T IO N S   REVEBIDICATIONS 1. A polymerizable composition containing a mineral filler characterized in that it comprises 90 to 20% by weight of a vinyl monomer and 10 to 80% by weight of a mineral filler dispersed in the vinyl monomer and in addition 0.1 at 5% by weight relative to the inorganic filler of a silane coupling agent and 0.01 to 2% by weight relative to the inorganic filler of a coupling with a silane.   2. A polymerizable composition containing a mineral filler characterized in that it comprises 90 to 20% by weight of a vinyl monomer and 10 to 80% by weight of a mineral filler dispersed in the vinyl monomer and in addition 0.1 to 5% by weight relative to the inorganic filler of a silane coupling agent, 0.01 to 2% by weight, based on the mineral filler, of a coupling accelerator with a silane and 5 & 50 X by weight, relative to the vinyl monomer, of a vinyl polymer which is soluble in the vinyl monomer at less by heating.   3. Composition according to claim 2, characterized in that it has been prepared by mixing the inorganic filler, the silane coupling agent and the coupling accelerator with a coupling agent.   silane in the vinyl monomer and then bulk polymerization   of the vinyl monomer in the presence of a polymer initiator.   until 5 to 45% of the vinyl monomer is polymerized so that the viscosity at 20C of the reaction system is adjusted between and 10,000 cP.   4. Composition according to claim 2 characterized in that it was prepared by mixing the inorganic filler, the silane coupling agent and the coupling accelerator with a silane in the vinyl monomer and adding the vinyl polymer   to adjust the viscosity at 20 C between 100 and 10 000 cP.   5. Process for producing a polymer particle containing at 80% by weight of a mineral filler, characterized in that it comprises mixing a mineral filler, a silane coupling agent, and a silane coupling accelerator in a vinyl monomer, the addition of a vinyl polymer which is soluble in the vinyl monomer at least by heating the mixture, to prepare a mixed composition having a viscosity at 20 ° C of 100 to 10,000 cP, introducing the composition into water containing a suspension stabilizer, and then heating the compositipn to effect suspension polymerization of the vinyl monomer 6. Process according to claim 5, characterized in that a swelling agent is added before or during the suspension polymerization.   7. Process for producing a polymer particle   10 to 80% by weight of a mineral filler, characterized in that   that it comprises the mixing of a mineral filler, a   silane type range and a silane coupling accelerator in a vinyl monomer, the bulk polymerization of the vinyl monomer in the presence of a polymerization initiator   until 5 to 45% by weight of the vinyl monomer is poly-   Meridized to adjust the viscosity of the reaction system at 200C to 10,000cP, the introduction of the preliminary mass polymerization solution of the vinyl monomer thus obtained into water containing a suspension stabilizer and heating the mixture obtained to perform suspension polymerization of the monomer unreacted vinyl.   8. Process for producing a polymer particle   10 to 80% by weight of a mineral filler, characterized in that it comprises mixing a mineral filler of a silane coupling agent and a coupling accelerator with an uilane in a   vinyl monomer, the preliminary bulk polymerization of the mono-   vinyl mother in the presence of a polymerization initiator until 5 to 45% by weight of the vinyl monomer is polymerized to adjust the viscosity of the reaction system at 200C between 100 and 10 000 cP> the continuous introduction of the solution preliminary mass polymerization of the vinyl monomer obtained in a bulk polymerization reactor and completion of bulk polymerization of the unreacted vinyl monomer in the polymerization reactor. 2503 1 68   9. Process according to claim 7, characterized in that a blowing agent is added to the mixed solution during or   after the suspension polymerization.   10. Composition according to any one of the claims   1-4 characterized in that the vinyl monomer is styrene.   11. Method according to any one of claims 5   at 8 characterized in that the vinyl monomer is styrene.