JP5419081B2 - Thermoplastic composite material - Google Patents

Description

  The present invention relates to a thermoplastic composite material.

  Various types of inorganic materials are used for industrial purposes in consideration of their respective characteristics and required characteristics. For example, silicon-based ceramics such as silicon carbide and silicon nitride are materials having excellent mechanical strength, chemical stability, and thermal stability. However, these inorganic materials are generally poor in moldability and may be hard. Moreover, the adhesiveness with an organic polymer is also bad and the use is restrict | limited.

  On the other hand, organic polymers are generally excellent in moldability and flexibility, but hardness and thermal stability are considerably inferior to those of inorganic materials. For this reason, development of a material that complements the characteristics of an inorganic material and an organic polymer and takes advantage of the advantages is eagerly desired.

  As one means, physical property modification is widely performed by mixing and dispersing inorganic reinforcing agents and fillers such as glass fibers, glass beads, silica, alumina, and calcium carbonate in an organic polymer. Such organic-inorganic composite materials have been studied for the purpose of imparting excellent properties such as hardness, strength, heat resistance, and weather resistance of inorganic materials to organic polymers.

  However, inorganic materials and organic polymers are generally incompatible, and it is not easy to control the dispersion state to be microscopic. Further, in order to increase the modification effect, it is important to disperse the inorganic material in a finer, more and as homogeneous manner as possible. However, as the inorganic material becomes finer, aggregation tends to occur and homogenous dispersion becomes difficult. Furthermore, there is a limit to the amount of inorganic material added, and if it exceeds a certain amount, a good composite material cannot be obtained, and the moldability tends to be poor, brittle, or cracks tend to occur.

  For this reason, in order to produce a high-performance organic-inorganic composite material, it is difficult to simply mix and disperse the inorganic material and the organic polymer, and it is necessary to develop a new technology. As one of the techniques for producing a high-performance organic-inorganic composite material, research for directly bonding an organic polymer and an inorganic element has been conducted. This method is considered to not only facilitate uniform and fine dispersion of nano-sized inorganic materials, but also significantly improve other physical properties such as mechanical strength.

  One of these is the development of materials in which inorganic elements such as Si, Ti and Zr are introduced into the material skeleton by using a sol-gel reaction with a metal alkoxide compound as the main raw material, and the organic polymer and inorganic material are homogeneously finely dispersed. It is actively done. However, since the sol-gel method is synthesized by hydrolysis and condensation reaction of alkoxy metal compounds, it is necessary to remove volatile components such as water and alcohol to be generated, and is inevitably limited to use in thin films. The In addition, a hydroxyl group or an alkoxy group remains in the inorganic substance, and problems such as foaming occur during actual use.

  In this way, it is common to synthesize organic / inorganic composite materials by a curing method or sol-gel method in which an organic polymer and nano-inorganic particles are directly bonded to each other, which are applied onto a substrate and hardened. The shape of the product, the molding method and the type of organic polymer were extremely limited.

  As a method for solving these problems, various methods have been studied in which a reactive compound is bonded to the surface of nano-sized fine particles synthesized beforehand and bonded to an organic polymer.

  For example, in Patent Document 1, a composite material in which carbon black and a polymer are connected by a covalent bond can be produced by melt-kneading carbon black fine particles and a polymer having a reactive group that reacts with a functional group on the surface of the carbon black. Has been reported.

  In Patent Document 2, a living radical polymerization initiating group is bonded to the surface of a nano-inorganic particle pigment, and then an organic polymer is grown from the surface of the nano-inorganic particle by performing living radical polymerization to produce a composite. Methods have been reported.

JP 2000-154327 A JP 2006-16488 A

  However, Patent Document 1 has a problem that it is difficult to react all functional groups in the melt mixing step and the molecular weight is not stable. In addition, there is a problem in use as a thermoplastic material because the remaining functional group reacts under the influence of light, heat, etc. after forming a molded body, and the composite gels or foams. .

  In Patent Document 2, it is possible to bind an organic polymer at a high density on the surface of nano-inorganic particles, and a composite material having excellent dispersibility of nano-inorganic particles can be obtained. Synthesis of nano-inorganic particles having an initiating group It is difficult to construct a mass synthesis process due to complicated operations such as washing. In addition, since one end of each polymer chain is fixed to the nano-inorganic particles, the entanglement with the other polymer chain is small and brittle. Therefore, even when the composite itself or another resin is mixed, there is a problem in the strength of the molded body.

  The simplest method of combining organic polymers and nano-inorganic particles is to synthesize organic polymers by radical polymerization in the presence of surface-modified nano-inorganic particles with radical-reactive double bonds bonded to the surface of the nano-inorganic particles. This is a method for producing a composite material. For example, Polymer. In 49.5636 (2008), a composite material in which an organic polymer and nano-inorganic particles are bonded can be obtained by living radical polymerization in the presence of silica particles having a radical reactive double bond bonded to the surface. Has been reported.

  However, since impurities are generated when the surface-modified nano-inorganic particles are prepared, a complicated operation for removing the impurities is required. In addition, even when impurities are removed, reactive functional groups remain on the surface of the nano-inorganic particles, causing problems such as gelation in the process of heat drying or molding, or foaming of the molded product. It was difficult to use as a plastic composite material.

  Because of these problems, the composite material using nano-inorganic particles is difficult to be processed and is limited to use in a thin film, so that the application range of the nano-material is extremely limited.

  Accordingly, an object of the present invention is to provide a thermoplastic composite in which an inorganic material can be homogeneously dispersed in a thermoplastic resin even when melt-molded, and gelation and foaming are reduced to such a level that there is no practical problem. It is to provide a method for manufacturing a material.

The present invention relates to the following [1] to [10].
[1] A method for producing a thermoplastic composite material, wherein a radically polymerizable monomer is living radically polymerized with a free initiator in the presence of nano-inorganic particles surface-modified with a coupling agent to form a thermoplastic resin. Then, the functional group of the coupling agent that causes the surface modification reaction and the remaining functional group that does not cause the reaction among the functional groups of the nano-inorganic particles are reacted with the functional group of the quenching agent before or after the living radical polymerization. ,Production method.
[2] The production method according to [1], wherein the radical polymerizable monomer is a (meth) acrylic acid ester. In addition, (meth) acryl means acryl or methacryl (it may be described as methacryl), and the same compound is also synonymous.
[3] The production method according to [1] or [2], wherein the coupling agent is a coupling agent having a radical reactive double bond.
[4] The method according to any one of [1] to [3], wherein the nano-inorganic particles are nano-inorganic particles having an average diameter of 50 nm or less made of an oxide of silicon, titanium, zirconium, or aluminum.
[5] The production method according to any one of [1] to [4], wherein the living radical polymerization is atom transfer radical polymerization.
[6] The production method according to any one of [1] to [4], wherein the living radical polymerization is reversible addition-fragmentation chain transfer polymerization.
[7] The production method according to any one of [1] to [6], wherein a conversion rate of the radical polymerizable monomer in the living radical polymerization is 60% or more and 95% or less.
[8] A composite material in which nano-inorganic particles having an average particle size of 100 nm or less are dispersed in a polymer obtained by polymerizing a radical polymerizable monomer, and the number average molecular weight Mn of the polymer is 10,000 to 500, The thermoplastic composite produced by the production method according to any one of [1] to [7], wherein the molecular weight distribution Mw / Mn is in the range of 1.1 to 1.5 at 000 g / mol material.
[9] The thermoplastic composite material according to [8], wherein foaming is not caused by heating at 200 ° C. for 1 hour in air.
[10] A molded article comprising the thermoplastic composite material according to [8] or [9].

  In the present invention, the organic polymer and the nano-inorganic particles are combined without gelation, and even when melt-molded, the nano-inorganic particles are suppressed from agglomeration and are transparent, and the thermoplastic composite does not cause problems such as foaming due to heating. A method of manufacturing the material is provided.

  The thermoplastic composite material synthesized in the present invention is synthesized by living radical polymerization, so that gelation is suppressed and a bond between the polymer and nano-inorganic particles is formed. Inorganic particles are present in a finely dispersed state. In addition, since there is no foaming of molded products due to volatile components, which is a problem in the sol-gel method, melt molding is possible, the range of application of nanocomposites is widened, and organic and inorganic thermoplastic composites with thick films and complex shapes Material can be obtained.

2 is a TEM photograph after injection molding the 12 wt% colloidal silica-containing polymethyl methacrylate composite material shown in Example 1. FIG. 6 is a TEM photograph after injection molding the 31 wt% colloidal silica-containing polymethyl methacrylate composite material shown in Example 2. FIG.

The present invention relates to a method for producing a thermoplastic composite material, in which a radically polymerizable monomer is living radically polymerized with a free initiator in the presence of nano-inorganic particles surface-modified with a coupling agent to form a thermoplastic resin. However, it is characterized by implementing the following (1) and / or (2).
(1) After nano-inorganic particles are surface-modified with a coupling agent, the remaining functional groups that have not caused the reaction are quenched among the coupling agent that causes a reaction of the surface modification and the functional groups of the nano-inorganic particles ( React with quencher functional groups).
(2) A cup that undergoes a surface modification reaction after forming a thermoplastic resin by living radical polymerization of a radically polymerizable monomer with a free initiator in the presence of nano-inorganic particles surface-modified with a coupling agent. Among the functional groups of the ring agent and nano-inorganic particles, the remaining functional group that has not caused the reaction is quenched (reacted with the functional group of the quenching agent).

  In any of (1) and (2), the functional group to be quenched is a functional group involved in surface modification. For example, even if a functional group not involved in surface modification is present in the coupling agent, The functional group need not be quenched.

  First, the nano inorganic particles used in the present invention will be described. The nano-inorganic particles only have to be in the nano-range (that is, if the average particle size is on the order of nanometers), and the chemical species constituting the nano-inorganic particles are arbitrary.

  The nano-inorganic particle has a functional group that reacts with the surface modification compound (coupling agent, quenching agent) on the surface of the nano-inorganic particle, or is treated with acid, base, plasma irradiation, etc. You may use what combined the functional group.

  For example, oxides such as Si, Ti, Zr, and Al, nitrides, elemental elements, metals, and alloys may be used. Specific examples of the inorganic oxide include silicon oxide (silica, silsesquioxanes), titanium oxide (titania), zirconium oxide (zirconia), aluminum oxide (alumina), and the like. Moreover, carbon materials, such as a carbon nanotube, fullerene, and carbon black, may be sufficient.

The nano inorganic particles may have any shape or crystal system, and the size (average particle size) is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 20 nm or less. If it is larger than 100 nm, there may be a problem such as light scattering when used as an optical material. Moreover, since the characteristic characteristic of the substance which comprises this microparticle | fine-particle may change when too small, the thing of 1 nm or more is preferable.

  These nano inorganic particles may be used in combination of two or more. Furthermore, in the characteristic, various things, such as a conductor, a semiconductor, an insulator, and a magnetic body, may be used.

  The surface modifying compound for modifying the surface of the nano-inorganic particles can be classified into two types: a coupling agent and a quenching agent.

  The coupling agent is a silane-based, titanium-based, or aluminum-based coupling agent having a functional group that reacts with the nano-inorganic particle surface and may have a radical reactive double bond. As the coupling agent, those having both a functional group that reacts with the nano-inorganic particle surface and a radical reactive double bond are particularly suitable.

  For example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyldimethylmethoxysilane, 3-methacryloxypropyltrichlorosilane, 3-methacryloxypropylmethyldichlorosilane, 3-methacryloxy Propyldimethylchlorosilane, 3-methacryloxyethyl isocyanate and the like are used as suitable coupling agents. These coupling agents may be directly bonded to the nano inorganic particles, or may be bonded to two or more directly bonded coupling agents. Depending on the coupling agent, water may be introduced to promote hydrolysis, and a catalyst may be used to promote the reaction with the nano-inorganic particle surface.

  As the quenching agent, a compound that reacts with the functional group remaining on the surface-modified nano-inorganic particles and / or the coupling agent is used. Specifically, the silanol group on the surface of the nano inorganic particles, the silanol group of the coupling agent, silylmethoxy group, silyl chloride group, isocyanate group, amino group, carboxylic acid group, hydroxyl group, epoxy group, phosphonium group, sulfonium group, or Examples of functional groups that can be quenched include urethane bonds.

  Quenching (sometimes referred to as “quenching reaction”) is a function that may react under the influence of heating, light, or water as described above at the timing of (1) and / or (2). This means that the group is left unreacted.

  In general, when an inorganic oxide reacts with a radical reactive coupling agent, it is extremely difficult to react all the hydroxyl groups on the inorganic surface, and some of the hydroxyl groups remain. Depending on the type of coupling agent, functional groups such as hydroxyl groups and alkoxy groups remain on the surface-modified inorganic oxide. In addition, the unreacted coupling agent is taken into the organic polymer in the polymerization process while leaving functional groups that easily react with the nano-inorganic particle surface. These remaining functional groups generate alcohol, water, and the like due to heat drying, heat processing, and moisture absorption of the molded body, and cause the molded body to foam. In addition, the composite material may be gelled or the nano inorganic particles may be aggregated. Therefore, when used as the thermoplastic composite material of the present invention, it is extremely important to quench and suppress this reaction.

  As the compound that can be a quenching agent, a compound that has a small steric hindrance and a high reactivity with the functional group on the surface of the nano-inorganic particles and / or the functional group of the coupling agent is preferably used. Examples thereof include hexamethyldisilazane and trimethylsilyl chloride.

When the reaction with the quenching agent when the surface of the nano-inorganic particles or the functional group of the coupling agent is —Si—OH, between the hexamethyldisilazane and —Si—OH + (CH ₃ ) ₃ Si— NH—Si (CH ₃ ) ₃ = —Si—O—Si (CH ₃ ) ₃ + (CH ₃ ) ₃ Si—NH ₂ is considered to occur, and there is —Si—OH + Cl— with trimethylsilyl chloride. It is considered that a reaction of Si (CH ₃ ) ₃ = —Si—O—Si (CH ₃ ) ₃ + HCl occurs.

  Two or more quenching agents may be used in combination. In addition, a compound that reacts with an acid such as hydrochloric acid generated by a quench reaction, such as triethylamine, may be used in combination. Furthermore, this reaction can be performed after the nano inorganic particles are surface-treated with a radical reactive coupling agent, or can be performed after polymerization.

  The method for adjusting the surface-modified nano-inorganic particles is preferably performed under the condition that the nano-inorganic particles do not aggregate. For example, when surface-modifying the organic solvent dispersion of colloidal silica used in the present application, it is preferable that the reaction is performed at a colloidal silica weight ratio of 50 wt% or less, preferably 40 wt% or less. Further, ultrasonic irradiation, microwave irradiation, or the like may be performed. Since the reaction conditions depend on the reactivity between the surface modification compound and the nano-inorganic particle surface, optimal surface modification conditions can be selected as appropriate.

  When the nano inorganic particles and the surface modification compound are reacted in a solvent, the solvent is not particularly limited, and any one that can dissolve or disperse the nano inorganic particles and the surface modification compound can be arbitrarily used. When carrying out the surface modification reaction of inorganic oxides, for example, water; alcohol solvents such as methanol, ethanol, isopropanol, n-propanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone; dimethyl sulfoxide; dimethylformamide; chloroform Halogen solvents such as dichloromethane; ether solvents such as diethyl ether, tetrahydrofuran and anisole; aromatic solvents such as benzene and toluene; hydrocarbon solvents such as pentane, hexane, octane, 2-ethylhexane and cyclohexane Can be mentioned. Of these, alcohol-based solvents, ketone-based solvents, and dimethylformamide are preferred because the dispersibility of the surface-modified inorganic oxide formed is good.

  After modifying the nano-inorganic particle surface with a coupling agent and quenching agent, if there are free coupling agents, quenching agents, or quenched compounds that have not reacted with the particle surface, they can be washed away. it can. The cleaning method is preferably performed under the condition that the nano-inorganic particles do not aggregate. For example, by adding a poor solvent such as hexane to the surface-modified nano-inorganic particle dispersion, and precipitating the surface-modified nano-inorganic particles and removing the supernatant several times, surface-modified nano-inorganic particles free of impurities can be obtained. It is done.

  Even when a free radical-reactive coupling agent is present, it can be used for polymerization as it is without washing and purification as long as the reactive functional group is not reacted by quenching. For example, after the reaction between colloidal silica and the coupling agent 3-methacryloxypropyldimethylmethoxysilane, the methoxysilane portion of the coupling agent may be left unreacted by treating with a quenching agent such as trimethylsilyl chloride. Therefore, problems such as gelation and foaming do not occur even when a free coupling agent is incorporated into the organic polymer. In this case, it is very preferable economically.

  Next, the thermoplastic composite material will be described.

  The thermoplastic composite material in the present invention is preferably a living radical polymerization of a monomer from a free initiator in the presence of a surface-modified nano-inorganic particle whose surface is modified with a radical reactive double bond. Can be synthesized.

  A free initiator means that the initiator is not immobilized on the nano-inorganic particle surface by a covalent bond or a coordinate bond. A method of synthesizing a polymer after immobilizing the living radical polymerization initiator on the surface of the nano-inorganic particles is also known, but there is almost no binding between the complexes in which the polymer is bonded to one nano-inorganic particle, Since there is little entanglement between polymers, it is difficult to maintain the strength as a molded body.

  The thermoplastic composite material in the present invention is synthesized by living radical polymerization that can synthesize a polymer with almost uniform length of each polymer chain, so the bond between the composites is controlled by the length of the polymer chain. Is possible. In addition, since the bimolecular termination reaction hardly occurs, excessive binding between the complexes can be controlled, and the composite material can be synthesized without gelation.

  On the other hand, when synthesized by free radical polymerization, the bimolecular termination reaction occurs frequently, and the surface-modified nano-inorganic particles become cross-linking points to generate ultrahigh molecular weight substances, so-called gels. When the gel is present in the composite material, not only problems such as mechanical strength, melt flowability, optical properties, etc., but also problems such as adhesion to the reaction vessel occur in the production process. It is not preferable. Therefore, it is important to polymerize under conditions that do not cause a bimolecular termination reaction.

  The resulting gel can be detected in two ways. In the first method, the polymerization solution is first added to a poor solvent such as methanol to precipitate a composite material, dried at room temperature, and then dissolved and dispersed in a good solvent such as tetrahydrofuran to prepare an approximately 0.1 wt% solution. To do. When this solution was passed through a filter having 0.2 micron pores, gel was formed during polymerization if there was insoluble matter or clogging or if the molecular weight before and after permeation changed. It can be judged.

  Actually, a composite material synthesized by free radical polymerization generates a gel having a number average molecular weight Mn of 2 million or more, and thus the molecular weight is changed by removing the gel after passing through a filter. Another method is to vacuum-dry the deposited composite material at 140 ° C., injection-mold it at a temperature of 230 ° C. or higher, and then create a diluting solution in the same manner as above, and pass through a filter to form a gel. Can be judged. Actually, when quenching is not performed, the remaining functional group reacts in the melt-kneading process to generate a gel. It was determined that a gel was formed by both methods.

  The foaming was judged by the following two methods. The first method was defined as foaming when a composite material obtained by vacuum drying at 140 ° C. had many fine foams having a diameter of 2 mm or less when heated by a hot press. In a state where the composite material was introduced into a hot press preheated to 240 ° C., heated without pressure for 4 minutes, pressurized with 5 MPa using a 1 mm-thick mold for 5 minutes, and then cooled to room temperature. Observed. Microfoaming was observed in composites that had not been quenched and purified of surface modified nano-inorganic particles. Moreover, when the hot press operation was repeated 5 to 6 times, a composite material that did not foam was obtained. This is probably because the remaining functional groups reacted by heating and foamed by generating volatile components. In the second method, foaming was observed in a state where a molded product having a thickness of 3 mm produced by injection molding at a temperature of 230 ° C. or higher was heated in air at 200 ° C. for 1 hour. It was judged that foaming occurred by both of these methods.

  In the present invention, the polymer synthesized by living radical polymerization has a number average molecular weight Mn of 10,000 to 500,000 g / mol and a molecular weight distribution Mw / Mn of that is easy for injection molding and extrusion molding. It is preferable that it is 1.1-1.5. When the polymer is larger than 500,000, the composite material has a higher molecular weight, and the melt fluidity may be extremely lowered. On the other hand, if it is less than 10,000, there is a possibility that sufficient strength as a molded article cannot be obtained. The molecular weight distribution is inevitably 1.5 or less because the molecular weight distribution is synthesized under the condition that the bimolecular termination reaction is unlikely to occur in order to suppress excessive binding between the complexes. If it is greater than 1.5, there is a possibility that some termination reaction has occurred during the polymerization, so that the composite material is more likely to gel. Here, the number average molecular weight Mn and the weight average molecular weight Mw are values determined by gel permeation chromatography (GPC) analysis, and the molecular weight distribution is a value calculated as Mw / Mn. In addition, the molecular weight of the polymer is known from J.I. Polym. Sci, Polymer. As described in Physics, 40, 2667 (2002), after treatment with an HF solution, only the polymer can be measured by GPC.

  As the living radical polymerization method, three methods are mainly known. Specifically, a method using a nitroxy radical (NMP; for example, JP-A-60-89452), an atom transfer radical polymerization method (ATRP; for example, JP-T-10-509475), reversible addition cleavage There is a chain transfer method (RAFT; for example, WO 98/01478). The atom transfer radical polymerization method (hereinafter referred to as “ATRP”) and the reversible addition-fragmentation chain transfer method (hereinafter referred to as “RAFT”) from the viewpoint of versatility of the polymerization initiator, the variety of applicable monomers, polymerization temperature, and the like. Is more preferred).

  In recent years, the ARGET ATRP method has been reported in which a divalent copper produced in an ATRP system is continuously reduced to active monovalent copper by adding a reducing agent for the purpose of improving the polymerization rate and ease of operation. (For example, Angew Chem, Int Ed, 45 (27), 4482 (2006)). Since the ratio of divalent copper and monovalent copper is kept in equilibrium by the addition of the reducing agent, a sufficient polymerization rate is maintained even when the monomer is consumed. Furthermore, if an appropriate reducing agent is added, the amount of copper to be used can be reduced to about 0.1 mol% or less, which is a preferable polymerization method. What is necessary is just to select suitably the reducing agent used by this method that the metal catalyst containing a metal can reduce | restore to the active state which generates a radical growth seed | species.

  The polymerization can be performed by various methods such as solution polymerization, suspension polymerization, and emulsion polymerization.

  The solvent is preferably a solvent having good dispersibility of the surface-modified nano inorganic particles and good solubility of the polymerization catalyst. Two or more solvents may be used in combination.

  The amount of the solvent used is, for example, preferably in the range of 0 to 2000 parts by mass and more preferably in the range of 10 to 1000 parts by mass with respect to 100 parts by mass of the monomer charge. When synthesizing the polymerization precisely in a short time, the range of 50 to 300 parts by mass is most preferable. The upper limits of these ranges are significant in terms of suppressing polymerization rate reduction and controlling polymerization. The lower limit is significant in terms of controlling the solution viscosity. In practice, when the amount of solvent is 50 parts by mass or less, the solution viscosity rapidly increases before reaching an appropriate conversion rate.

  As the polymerization initiator, a compound having a group generally known as an initiator group for living radical polymerization can be preferably used. For example, in ATRP, a compound having a halogenated alkyl group or a halogenated sulfonyl group is generally used as an initiator. In RAFT, azobisisobutyronitrile (AIBN) or the like is used. The initiator used in this study is not one that is covalently immobilized on the nano-inorganic particle surface, but one that exists in the polymerization system in a free state.

It is preferable to use a catalyst for the polymerization. In the case of ATRP, the type of catalyst may be appropriately selected from various commonly known types according to the polymerization method. For example, when ATRP is used as the polymerization method, a metal catalyst containing a metal such as Cu (0), Cu ⁺ , Cu ²⁺ , Fe ⁺ , Fe ²⁺ , Fe ³⁺ , Ru ²⁺ , Ru ³⁺ can be used. In order to achieve a high degree of control of molecular weight and molecular weight distribution, monovalent copper compounds containing Cu + or zero-valent copper are particularly preferred. Specific examples thereof include Cu (0), CuCl, CuBr, Cu2O and the like. The amount of the catalyst to be used is generally 0.01-100 mol, preferably 0.01-50 mol, more preferably 0.01-10 mol, per 1 mol of the polymerization initiator.

  Moreover, an organic ligand is usually used for the metal catalyst described above. Examples of the coordination atom to the metal include a nitrogen atom, an oxygen atom, a phosphorus atom, and a sulfur atom. Of these, a nitrogen atom and a phosphorus atom are preferable. Specific examples of the organic ligand include 2,2′-bipyridine and derivatives thereof, 1,10-phenanthroline and derivatives thereof, tetramethylethylenediamine, pentamethyldiethylenetriamine, tris (dimethylaminoethyl) amine (Me6TREN), tris ( 2-pyridylmethyl) amine, triphenylphosphine, tributylphosphine and the like. 2,2'-bipyridine and its derivatives are preferred when polymerizing acrylic esters and methacrylic esters.

  The metal catalyst and the organic ligand may be added separately and mixed in the polymerization system, or may be mixed in advance and added to the polymerization system. In particular, when using a copper compound, the former method is preferable.

  In the RAFT method, an organic sulfur compound such as a dithiocarboxylic acid ester serving as a chain transfer agent can be used as a catalyst.

  For example, when the ATRP method or the RAFT method is used, the polymerization temperature is usually −50 ° C. to 200 ° C., preferably 0 ° C. to 150 ° C., more preferably 20 ° C. to 130 ° C. When polymerizing acrylic acid esters and methacrylic acid esters, precise polymerization can be carried out in a relatively short period of time when carried out at 50 to 130 ° C.

  The polymerization is preferably performed in a state where the monomer conversion is 60% or more. When the conversion rate is lower than 60%, there is an economical problem. When the conversion rate is higher than 95%, a bimolecular termination reaction occurs also in the living radical polymerization, so that the possibility of forming a gel increases. Preferably, it is 70 to 95%, more preferably 80 to 95%.

  The radical polymerizable monomer used in the present invention may be any addition polymerizable monomer that can be polymerized by ATRP method or RAFT method. For example, ethylene; buta-1,3-diene, 2-methylbuta-1, Dienes such as 3-diene and 2-chlorobuta-1,3-diene; styrenes such as styrene and α-methylstyrene; acrylates such as methyl acrylate and butyl acrylate, methyl methacrylate and methacrylic acid Methacrylic acid esters such as ethyl; (meth) acrylic acid derivatives such as 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, acrylonitrile and methacrylonitrile; vinyl such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate Esters; vinyl methyl ether, vinyl ethyl Vinyl ethers such as ether; N-vinyl compounds such as vinyl methyl ketone, vinyl hexyl ketone, vinyl ketones, N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone; allyl alcohol, allyl chloride, Examples include allyl compounds such as allyl acetate, vinyl chloride, and vinylidene chloride; compounds having a fluorine alkyl group such as vinyl fluoride and vinylidene fluoride. These may be used alone or in combination of two or more. You may use together. Preferred in the radical polymerization are styrene, acrylonitrile, methyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, vinyl acetate and vinyl chloride. When producing a transparent hybrid material, (meth) acrylic acid esters such as methyl methacrylate and methyl acrylate and styrenes are particularly preferable.

  The thermoplastic resin constituting the thermoplastic composite material may take various structures such as a block, graft, star, and ladder type. In that case, it may be used in combination with a polymerization method other than living radical polymerization. By selecting the polymer structure and comonomer according to the purpose, it is possible to improve physical properties such as dispersion of nano-inorganic particles and improvement of mechanical strength.

  In particular, it is preferable to introduce a rubber component with a block polymer in order to improve the mechanical strength of a composite material that is hard and brittle. For example, a block polymer of methyl methacrylate and butyl acrylate forms a microphase-separated structure in a self-organizing manner, so that mechanical strength such as impact resistance is improved while maintaining transparency.

  Moreover, in the composite of the block polymer and the nano-inorganic particles, the arrangement of the nano-inorganic particles can be controlled by mainly binding one of the block segments and the nano-inorganic particles. For example, polybutyl acrylate is compounded with nano-inorganic particles by polymerizing butyl acrylate in the presence of surface-modified nano-inorganic particles using polymethyl methacrylate with halogen bonded to the terminal synthesized by living radical polymerization. Thus, a block polymer in which the polymethyl methacrylate segment is not complexed can be obtained. This block composite material can form a phase separation structure such as a sea-island structure, a lamellar structure, or a cylinder structure by changing the composition ratio, and nano-inorganic particles can be locally arranged. When nano-inorganic particles are compounded with polybutyl acrylate segments, they are effective for improving mechanical strength, and when compounded with polymethyl methacrylate, they are improved in hardness, glass transition temperature, scratch resistance, mechanical properties, etc. It is effective for improving the strength. In either case, the effect of the composite can be selectively improved with a small amount of nano-inorganic particles, which is an economical method.

In addition, it is possible to improve the dispersibility and compatibility by grafting a hydrophilic substituent having high affinity with the nano-inorganic particles, or a monomer having a phosphonium group or a sulfonium group.
In addition, the polymer chain to be grafted may have a reactive substituent such as an epoxy group or an isocyanate group. After grafting the polymer, various reactive substituents introduced into the polymer chain may be used. The reaction can be performed.
In addition, for thermoplastic composite materials, stabilizers such as antioxidants, metal deactivators, phosphorus processing stabilizers, UV absorbers, UV stabilizers, fluorescent whitening agents, or crosslinking agents, chaining agents, and chaining agents are optionally added. Additives such as transfer agents, nucleating agents, lubricants, plasticizers, fillers, reinforcing agents, pigments, dyes, flame retardants, antistatic agents, and nano-inorganic particle dispersion aids such as surfactants are effective for the present invention. You may add within the range which does not impair.

As a molding method of the thermoplastic composite material in the present invention, a general thermoplastic resin material molding method such as injection molding, extrusion molding, compression molding, cast molding or the like can be employed.
The thermoplastic composite material obtained by the present invention is suitable as a molded body in the fields of optical materials, electronic materials, adhesives, hard coats, etc., in addition to conventional thin film fields such as curable composite materials and composite materials by the sol-gel method. Available to: In particular, it is suitably used for optical parts utilizing the excellent optical properties of thermoplastic composite materials, such as lenses, optical waveguides, optical disks, antireflection films, and conductive films.

  The present invention will be described based on examples. The present invention is not limited to these.

[Analysis method]
(1) Molecular weight (Mn, Mw, Mw / Mn)
Two columns (TSKgel GMHXL, 40 ° C.) were connected to HLC-8020 manufactured by Tosoh Corporation, and measurement was performed with a GPC apparatus equipped with an RI detector. Tetrahydrofuran was used as the mobile phase and alphamethylstyrene dimer was used as the internal standard. The molecular weight was calculated in terms of polymethyl methacrylate by creating a calibration curve using polymethyl methacrylate standard (manufactured by Tosoh Corporation).

(2) Glass transition temperature (Tg)
It calculated | required based on JIS-K-7121 using DSC-7 made from Perkin Elmer. Specifically, the temperature was raised from room temperature to 250 ° C. at 10 ° C./min under nitrogen, then returned to room temperature at 10 ° C./min, and again raised to 250 ° C. at 10 ° C./min. The glass transition temperature measured in the second temperature raising process was defined as Tg.

(3) Measurement of the weight of nano-inorganic particles in the thermoplastic composite Using a thermogravimetric measuring device TGA-50 manufactured by Shimadzu Corporation, the sample was heated from 25 ° C. to 500 ° C. at 20 ° C./min under a nitrogen stream containing 1% oxygen. The weight after standing at that temperature for 1 hour was measured.

(4) Transmission electron microscope (TEM)
An ultrathin section having a thickness of about 45 nm was prepared with REICHRT ULTRACUT S manufactured by Leica, and observed with JEM-2100 manufactured by JEOL.

(5) Total light transmittance It calculated | required based on JIS-K-7361-1 using the integrating sphere type measuring apparatus by Suga Test Instruments.

[Synthesis method]
As the silica, NBAC-ST manufactured by Nissan Chemical Co., Ltd., which is a butyl acetate dispersion of colloidal silica 30 wt%, was used. As zirconia, OZ-S30K manufactured by Nissan Chemical Co., Ltd., which is a colloidal zirconia 20 wt% methyl ethyl ketone dispersion, was used. For both silica and zirconia, the amount of surface hydroxyl groups was calculated assuming 2.18 mmol / g.

Method for synthesizing surface-modified nano-inorganic particles
[Synthesis Example 1: Method for synthesizing surface-modified colloidal silica]
NBAC-ST (327.9 g), which was bubbled with nitrogen for 30 minutes, and 3-methacryloxypropyldimethylmethoxysilane (hereinafter, referred to as MS) 9.4 ml, 43.8 mmol, were added to a 1 L flask purged with nitrogen. MS surface-modified colloidal silica dispersion was synthesized by introducing 20 mol% of the amount of hydroxyl group on the colloidal silica surface and stirring for 24 hours at room temperature.

[Synthesis Example 2: Reaction of colloidal silica and coupling agent]
The same method as in Synthesis Example 1 except that the coupling agent was changed to 3-methacryloxypropyltrimethoxysilane (hereinafter referred to as TS. 10.4 ml, 43.8 mmol, 20 mol% of the surface hydroxyl amount of colloidal silica). A TS surface modified colloidal silica dispersion was synthesized.

[Synthesis Example 3; Reaction of Colloidal Silica and Coupling Agent]
Synthesis Example except that 3-methacryloxypropyldimethylchlorosilane (hereinafter referred to as CS. 9.5 ml, 43.8 mmol, 20 mol% of the surface hydroxyl amount of colloidal silica) was introduced as a coupling agent and heated under reflux for 24 hours. 1 was used to synthesize a CS surface-modified colloidal silica dispersion.

[Synthesis Example 4; Reaction of colloidal zirconia and coupling agent]
An MS surface-modified colloidal zirconia dispersion was synthesized in the same manner as in Synthesis Example 1 except that OZ-S30K (501.7 g) was used.

[Synthesis Example 5; quench reaction]
Trimethylsilyl chloride (2.8 ml, 21.9 mmol) and triethylamine (3.1 ml, 21.9 mmol) were added to the MS surface-modified colloidal silica dispersion prepared in Synthesis Example 1 under nitrogen and stirred at room temperature for 12 hours. As a result, the remaining functional group was quenched.

[Synthesis Example 6; quench reaction]
Synthesis Example 5 except that trimethylsilyl chloride (16.7 ml, 131.2 mmol) and triethylamine (18.3 ml, 131.2 mmol) were added to the TS surface-modified colloidal silica dispersion prepared in Synthesis Example 2 under nitrogen. The residual functional group was quenched by the same method as described above.

[Synthesis Example 7; quench reaction]
The remaining functional groups were synthesized in the same manner as in Synthesis Example 5 except that hexamethyldisilazane (9.1 ml, 43.8 mmol) was added under nitrogen to the CS surface-modified colloidal silica dispersion prepared in Synthesis Example 3. A quench reaction was performed.

[Synthesis Example 8; quench reaction]
The residual functional group was quenched by the same method as in Synthesis Example 5 except that the MS surface-modified colloidal zirconia dispersion prepared in Synthesis Example 4 was used.

[Synthesis Example 9; Purification of surface-modified colloidal silica]
50 ml of the MS surface-modified colloidal silica dispersion liquid quenched in Synthesis Example 5 was introduced into 400 ml (3/1 wt%) of methanol / water to precipitate the surface-modified colloidal silica. After separation with a centrifuge, the supernatant was removed, 30 ml of butyl acetate was added, and redispersed while being irradiated with ultrasonic waves. Next, 400 ml of hexane was added to cause reprecipitation. The operation of dispersing with butyl acetate and precipitating with hexane was repeated 5 times, and finally the supernatant was removed and butyl acetate was added to prepare a surface-modified colloidal silica butyl acetate dispersion containing 28 wt% colloidal silica.

[Synthesis Example 10; Purification of surface-modified colloidal silica]
A surface-modified colloidal silica butyl acetate dispersion having a colloidal silica content of 30 wt% was prepared in the same manner as in Synthesis Example 9 except that the TS surface-modified colloidal silica dispersion subjected to quench treatment in Synthesis Example 6 was used.

[Synthesis Example 11; Purification of surface-modified colloidal silica]
A surface-modified colloidal silica butyl acetate dispersion having a colloidal silica content of 30 wt% was prepared in the same manner as in Synthesis Example 9, except that the CS surface-modified colloidal silica dispersion subjected to quench treatment in Synthesis Example 7 was used.

[Synthesis Example 12; Purification of surface-modified colloidal zirconia]
A surface-modified colloidal zirconia butyl acetate dispersion having a colloidal zirconia content of 30 wt% was prepared in the same manner as in Synthesis Example 9 except that the MS surface-modified colloidal zirconia dispersion liquid quenched in Synthesis Example 8 was used.

[Example 1]
Methods for synthesizing thermoplastic composites with ATRP All experiments were performed under nitrogen. Moreover, the colloidal silica dispersion liquid, the colloidal zirconia dispersion liquid, the monomer, and the solvent used nitrogen-bubbling for 30 minutes to remove oxygen.

To a 3 L flask, add cuprous chloride (2.2 g, 15.0 mmol, 2500 ppm with respect to the monomer), 2,2′-bipyridine (4.7 g, 30.0 mmol, 5000 ppm with respect to the monomer) and replace with nitrogen. went. After adding 593 ml of anisole, the flask was immersed in a hot water bath at 80 ° C. to dissolve the catalyst. Next, methyl methacrylate (641.0 ml, 6.0 mol) from which the polymerization inhibitor was removed through an alumina column and 489 ml of butyl acetate were added, and then a butyl acetate dispersion 238 of the surface-modified colloidal silica prepared in Synthesis Example 5 was obtained. .1 g (66.7 g as surface-modified colloidal silica) and 10 ml of anisole solution of initiator p-toluenesulfonyl chloride (hereinafter referred to as p-TsCl; 2.3 g, 12.0 mmol) were added in this order to start the reaction. did. The solvents, anisole and butyl acetate, were introduced so as to be 100 wt% with respect to each monomer, and the monomer / initiator ratio was adjusted to 500/1.
After 46 hours, the polymerization was stopped at a conversion rate of 83%. The obtained composite material liquid was poured into methanol to precipitate a polymer and washed several times, followed by vacuum drying at 140 ° C. for 12 hours. The amount of colloidal silica in the composite material was 12 wt%, Tg was 125 ° C., and the total light transmittance of a 3 mm-thick molded product obtained by injection molding at a nozzle temperature of 240 ° C. was 91%. The number average molecular weight Mn of the polymer after treatment with HF was 51,000 g / mol, and the molecular weight distribution Mw / Mn was 1.15. Neither fine foaming nor gel was observed.
1 is a TEM (transmission electron microscope) photograph after injection molding of 12 wt% colloidal silica-containing polymethylmethacrylate composite material of Example 1. FIG.

[Example 2]
With respect to the surface-modified colloidal silica, anisole and butyl acetate as the solvents were used except that the butyl acetate solution of the surface-modified colloidal silica prepared in Synthesis Example 5 was changed to 833.3 g (233.3 g as surface-modified colloidal silica). Were 100 wt% with respect to each monomer and the monomer / initiator ratio was 500/1, and composite materials were obtained in the same manner as in Example 1.
The conversion in 48 hours after the polymerization was stopped was 85%, the amount of colloidal silica in the composite material was 31 wt%, Tg was 130 ° C., and all of the 3 mm thick molded products obtained by injection molding at a nozzle temperature of 250 ° C. The light transmittance was 90%. The number average molecular weight Mn of the polymer after treatment with HF was 53,200 g / mol, and the molecular weight distribution Mw / Mn was 1.18. Neither fine foaming nor gel was observed.
FIG. 2 is a TEM (transmission electron microscope) photograph after injection-molding the 31 wt% colloidal silica-containing polymethylmethacrylate composite material shown in Example 2.

[Example 3]
For the surface-modified colloidal silica, 1.3 kg of the butyl acetate solution of the surface-modified colloidal silica prepared in Synthesis Example 5 (400.0 g as the surface-modified colloidal silica) was used, and anisole and butyl acetate as solvents were used. Except for changing to 100 wt% / 170 wt% with respect to the monomer, the monomer / initiator ratio was 500/1, and a composite material was obtained in the same manner as in Example 1.

  The conversion in 48 hours after the polymerization was stopped was 65%, the amount of colloidal silica in the composite material was 51 wt%, Tg was 135 ° C., and all of the 3 mm thick molded products obtained by injection molding at a nozzle temperature of 250 ° C. The light transmittance was 88%. The number average molecular weight Mn of the polymer after treatment with HF was 41,100 g / mol, and the molecular weight distribution Mw / Mn was 1.24. Neither fine foaming nor gel was observed.

[Example 4]
A composite material was obtained in the same manner as in Example 1 except that the ratio of the monomer / initiator was changed to 2000/1 by changing the initiator p-TsCl (0.6 g, 3.0 mmol).
The conversion rate in 55 hours after the polymerization was stopped was 71%, the amount of colloidal silica in the composite material was 12 wt%, Tg was 126 ° C., and the entire 3 mm molded product obtained by injection molding at a nozzle temperature of 250 ° C. The light transmittance was 90%. The number average molecular weight Mn of the polymer after the treatment with HF was 153,600 g / mol, and the molecular weight distribution Mw / Mn was 1.32. Neither fine foaming nor gel was observed.

[Example 5]
Using the butyl acetate solution of the surface-modified colloidal silica prepared in Synthesis Example 1, trimethylsilyl chloride (2.8 ml, 21.9 mmol) and triethylamine (3.1 ml, 21.9 mmol) were added after the polymerization was completed. Except for stirring for 12 hours, anisole and butyl acetate as solvents were 100 wt% with respect to each monomer, and the monomer / initiator ratio was 500/1, and a composite material was obtained in the same manner as in Example 1. .

  The conversion in 48 hours after the polymerization was stopped was 88%, the amount of colloidal silica in the composite material was 13 wt%, Tg was 125 ° C., and all of the 3 mm thick molded products obtained by injection molding at a nozzle temperature of 240 ° C. The light transmittance was 90%. The number average molecular weight Mn of the polymer after treatment with HF was 49,900 g / mol, and the molecular weight distribution Mw / Mn was 1.17. Neither fine foaming nor gel was observed.

[Example 6]
Anisole and butyl acetate as solvents except that the surface-modified colloidal silica was changed to a surface-modified colloidal zirconia butyl acetate solution (333.3 g, 66.7 g as surface-modified colloidal zirconia) prepared in Synthesis Example 8. Were 100 wt% with respect to each monomer and the monomer / initiator ratio was 500/1, and composite materials were obtained in the same manner as in Example 1.
The conversion in 46 hours after the polymerization was stopped was 78%, the amount of colloidal zirconia in the composite material was 22 wt%, Tg was 127 ° C., and all of the 3 mm thick molded products obtained by injection molding at a nozzle temperature of 240 ° C. The light transmittance was 83%. The number average molecular weight Mn of the polymer after treatment with HF was 43,200 g / mol, and the molecular weight distribution Mw / Mn was 1.26. Neither fine foaming nor gel was observed.

[Example 7]
Anisole and butyl acetate as solvents except that the surface-modified colloidal silica was changed to 238.1 g of the surface-modified colloidal silica butyl acetate dispersion prepared in Synthesis Example 7 (66.7 g as surface-modified colloidal silica). Were 100 wt% of the monomer and the monomer / initiator ratio was 500/1, and a composite material was obtained in the same manner as in Example 1.
The conversion in 48 hours after the polymerization was stopped was 83%, the amount of colloidal silica in the composite material was 29 wt%, Tg was 131 ° C., and all of the 3 mm thick molded products obtained by injection molding at a nozzle temperature of 240 ° C. The light transmittance was 90%. The number average molecular weight Mn of the polymer after treatment with HF was 51,100 g / mol, and the molecular weight distribution Mw / Mn was 1.20. Neither fine foaming nor gel was observed.

[Example 8]
Anisole and butyl acetate as solvents except that the surface-modified colloidal silica was changed to 238.1 g of a butyl acetate dispersion of the surface-modified colloidal silica prepared in Synthesis Example 6 (66.7 g as surface-modified colloidal silica). Were 100 wt% of the monomer and the monomer / initiator ratio was 500/1, and a composite material was obtained in the same manner as in Example 1.
The conversion rate in the 48 hours after the polymerization was stopped was 87%, the amount of colloidal silica in the composite material was 28 wt%, Tg was 126 ° C, and the entire 3 mm molded product obtained by injection molding at a nozzle temperature of 240 ° C was used. The light transmittance was 90%. The number average molecular weight Mn of the polymer after treatment with HF was 54,200 g / mol, and the molecular weight distribution Mw / Mn was 1.21. Neither fine foaming nor gel was observed.

[Example 9]
Method for synthesizing thermoplastic composites by RAFT RAFT reagent 4-cyano-4- (dodecylsulfanylthiocarbonyl) sulfanylpentanoic acid (4.8 g, 12.0 mmol), 2,2′-azobis (isobutyrate) synthesized in a 3 L flask (Nitrile) (hereinafter referred to as AIBN, 0.4 g, 2.4 mmol) was added to perform nitrogen substitution. After adding 489.5 ml of butyl acetate and methyl methacrylate (641.0 ml, 6.0 mol) from which the polymerization inhibitor was removed through an alumina column, 222.2 g of a butyl acetate solution of the surface-modified colloidal silica prepared in Synthesis Example 7 (66.7 g as surface-modified colloidal silica) was added and the flask was immersed in a 60 ° C. hot water bath to initiate the reaction. The solvent, butyl acetate, was introduced so as to be 100 wt% of the monomer, and the ratio of monomer / RAFT reagent / initiator was adjusted to 500/1 / 0.2.

  After 40 hours, the polymerization was stopped at a conversion rate of 64%. The obtained composite material liquid was poured into methanol to precipitate a polymer, washed several times, and then vacuum-dried at 140 ° C. for 12 hours. The amount of colloidal silica in the composite was 14 wt%, Tg was 126 ° C., and the total light transmittance of a 3 mm-thick molded product obtained by injection molding at a nozzle temperature of 240 ° C. was 90%. The number average molecular weight Mn of the polymer after treatment with HF was 50,000 g / mol, and the molecular weight distribution Mw / Mn was 1.16. Neither fine foaming nor gel was observed.

[Example 10]
Except for changing the surface-modified colloidal silica to a butyl acetate solution of surface-modified colloidal silica prepared in Synthesis Example 11 (857.1 g, 257.1 g as surface-modified colloidal silica), butyl acetate, which is a solvent, A composite material was obtained in the same manner as in Example 5 with 100 wt% of monomer and the ratio of monomer / RAFT reagent / initiator being 500/1 / 0.2.
In 45 hours after the polymerization was stopped, the conversion rate was 69%, the amount of colloidal silica in the composite material was 31 wt%, the Tg was 131 ° C., and the entire 3 mm thick molded product obtained by injection molding at a nozzle temperature of 250 ° C. The light transmittance was 90%. The number average molecular weight Mn of the polymer after treatment with HF was 52,800 g / mol, and the molecular weight distribution Mw / Mn was 1.11. Neither fine foaming nor gel was observed.

[Comparative Example 1]
Method for synthesizing thermoplastic composite by free radical polymerization (hereinafter referred to as FRP) AIBN (3.9 g, 24.0 mmol) was added to a 3 L flask, and nitrogen substitution was performed. After adding 722.3 ml of butyl acetate and methyl methacrylate (641.0 ml, 6.0 mol) from which the polymerization inhibitor had been removed through an alumina column, 238. butyl acetate solution of surface-modified colloidal silica prepared in Synthesis Example 5 1 g (66.7 g as surface-modified colloidal silica) was added and the flask was immersed in an 80 ° C. hot water bath to initiate the reaction. The solvent, butyl acetate, was introduced so as to be 125 wt% of the monomer, and the monomer / initiator ratio was adjusted to 100 / 0.4.

  After 6 hours, the polymerization was stopped at a conversion rate of 85%. The obtained composite material liquid was poured into methanol to precipitate a polymer, washed several times, and then vacuum-dried at 140 ° C. for 12 hours. The amount of colloidal silica in the composite material was 11 wt%, Tg was 125 ° C., and the total light transmittance of a 3 mm-thick molded product obtained by injection molding at a nozzle temperature of 240 ° C. was 90%. The number average molecular weight Mn of the polymer after treatment with HF was 32,600 g / mol, and the molecular weight distribution Mw / Mn was 1.92. Moreover, although fine foaming was not observed, gel was observed.

[Comparative Example 2]
The surface-modified colloidal silica was replaced with 238.1 g of a butyl acetate solution of the surface-modified colloidal silica prepared in Synthesis Example 1 (66.7 g as surface-modified colloidal silica) in the same manner as in Comparative Example 1. A composite material was obtained.
The conversion rate in 6 hours after the polymerization was stopped was 83%, the amount of colloidal silica in the composite material was 13 wt%, Tg was 123 ° C., and all of the 3 mm thick molded products obtained by injection molding at a nozzle temperature of 240 ° C. The light transmittance was 88%. The number average molecular weight Mn of the polymer after the treatment with HF was 38,800 g / mol, and the molecular weight distribution Mw / Mn was 2.10. Both fine foaming and gel were observed.

[Comparative Example 3]
Except not using surface-modified colloidal silica, the solvent of anisole and butyl acetate was 100 wt% of the monomer and the monomer / initiator ratio was 500/1, and polymethyl methacrylate was obtained in the same manner as in Example 1. It was.
In 48 hours after the polymerization was stopped, the conversion rate was 85%, Tg was 121 ° C., and the 3 mm-thick molded product obtained by injection molding at a nozzle temperature of 230 ° C. had a total light transmittance of 92%. The number average molecular weight Mn of the obtained polymer was 50,200 g / mol, and the molecular weight distribution Mw / Mn was 1.14. Neither fine foaming nor gel was observed.

[Comparative Example 4]
Implementation was performed except that the surface-modified colloidal silica was changed to 238.1 g of a butyl acetate solution of the surface-modified colloidal silica prepared in Synthesis Example 1 in which the quench reaction was not performed (66.7 g as the surface-modified colloidal silica). A composite material was obtained in the same manner as in Example 1.
The amount of colloidal silica in the composite material was 11 wt%, and Tg was 125 ° C. The total light transmittance of a molded article having a thickness of 3 mm obtained by injection molding at a nozzle temperature of 240 ° C. was 89%. The number average molecular weight Mn of the polymer after treatment with HF was 57,500 g / mol, and the molecular weight distribution Mw / Mn was 1.21. Both fine foaming and gel were observed.

[Comparative Example 5]
238.1 g of a butyl acetate solution of surface-modified colloidal silica prepared by washing in the same manner as in Synthesis Example 9 without quenching the surface-modified colloidal silica of Synthesis Example 2 (66. A composite material was obtained in the same manner as in Example 1 except that the amount was changed to 7g).
The amount of colloidal silica in the composite material was 13 wt%, and Tg was 125 ° C. The total light transmittance of a molded article having a thickness of 3 mm obtained by injection molding at a nozzle temperature of 240 ° C. was 89%. The number average molecular weight Mn of the polymer after treatment with HF was 54,100 g / mol, and the molecular weight distribution Mw / Mn was 1.28. Both fine foaming and gel were observed.

  The thermoplastic composite material obtained by the production method of the present invention can be suitably used in the fields of optical materials, electronic materials, adhesives and the like as molded articles, in addition to conventional fields such as hard coating.

Claims (10)

A method for producing a thermoplastic composite material, wherein in the presence of nano-inorganic particles surface-modified with a coupling agent, a radically polymerizable monomer is living radically polymerized with a free initiator to form a thermoplastic resin,
Production of reacting the functional group of the quenching agent before or after the living radical polymerization, among the functional groups of the coupling agent and nano-inorganic particles causing the surface modification reaction, before or after the living radical polymerization Method.   The production method according to claim 1, wherein the radical polymerizable monomer is a (meth) acrylic acid ester.   The manufacturing method according to claim 1, wherein the coupling agent is a coupling agent having a radical reactive double bond.   The said nano inorganic particle is a manufacturing method as described in any one of Claims 1-3 which is a nano inorganic particle which consists of an oxide of silicon, titanium, zirconium, or aluminum and whose average diameter is 50 nm or less.   The said living radical polymerization is a manufacturing method as described in any one of Claims 1-4 which is atom transfer radical polymerization.   The said living radical polymerization is a manufacturing method as described in any one of Claims 1-4 which is reversible addition cleavage chain transfer polymerization.   The manufacturing method as described in any one of Claims 1-6 whose conversion rate of the said radically polymerizable monomer in the said living radical polymerization is 60% or more and 95% or less. A thermoplastic composite material produced by the production method according to any one of claims 1 to 7,
Nano-inorganic particles having an average particle size of 100 nm or less are dispersed in a polymer obtained by polymerizing a radical polymerizable monomer, and the number average molecular weight Mn of the polymer is 10,000 to 500,000 g / mol, A thermoplastic composite material having a molecular weight distribution Mw / Mn in the range of 1.1 to 1.5.   The thermoplastic composite material according to claim 8, wherein foaming does not occur by heating at 200 ° C for 1 hour in air. A molded article comprising the thermoplastic composite material according to claim 8 or 9.