JP7680204B2 - Organic-inorganic composite composition and molded article made of the same - Google Patents

Description

The present invention relates to an organic-inorganic composite composition in which inorganic particles are dispersed in a thermoplastic resin, and to a molded article made from the same.

In recent years, the signal bands of information and communication devices such as mobile phones have become increasingly higher in frequency. As radio waves become higher in frequency, the dielectric properties of dielectrics become important in reducing losses during high-frequency propagation. Heat loss within a dielectric is proportional to the loss factor, which is expressed as the product of the dielectric constant and the dielectric tangent, so low dielectric properties are required for materials that make up devices that handle high-frequency signals.

In general, the dielectric properties of a resin material are determined by the molecular structure of its constituent units, so one approach to lowering the dielectric constant is to design the molecular skeleton. However, there are limits to how much the dielectric constant can be reduced by controlling the molecular skeleton, and changes to the molecular skeleton can cause problems such as changes in the strength of the resin molded product.

As another attempt to lower the dielectric constant, various methods of incorporating inorganic fillers have been proposed (Patent Document 1). Although this method can lower the dielectric constant to some extent by adding inorganic fillers with low dielectric properties, it requires the addition of a large amount of inorganic filler, which has problems such as reduced transparency and mechanical properties.

JP 2010-129387 A

The object of the present invention is to provide an organic-inorganic composite composition and a molded article made from the same that has excellent transparency and a low dielectric constant without causing a deterioration in the inherent mechanical properties of the resin by dispersing a very small amount of inorganic fine particles in a thermoplastic resin.

As a result of extensive research, the inventors have surprisingly found that an organic-inorganic composite composition in which a specific amount of inorganic fine particles having a specific particle size is blended with a thermoplastic resin has good transparency and low dielectric properties, and have thus completed the present invention.
That is, according to the present invention, the following (Configuration 1) to (Configuration 10) are provided.

(Configuration 1)
An organic-inorganic hybrid composition comprising a thermoplastic resin (A) and inorganic fine particles (B), wherein the content of the inorganic fine particles (B) is 8 mass% or less when the entire organic-inorganic hybrid composition is taken as 100 mass%, and the average particle diameter of the inorganic fine particles (B) in the organic-inorganic hybrid composition is 1 to 85 nm.
(Configuration 2)
2. The organic- _inorganic hybrid composition according to item 1 above, wherein the inorganic fine particles (B) are at least one selected from the group consisting of _ZrO2 (zirconium oxide), _TiO2 (titanium oxide), _SnO2 (tin oxide), _SiO2 (silicon oxide), _Al2O3 (aluminum oxide), ZnO (zinc oxide) and MgO (magnesium oxide).
(Configuration 3)
3. The organic-inorganic hybrid composition according to item 1 or 2 above, wherein the inorganic fine particles (B) are modified with a surface modifying agent.
(Configuration 4)
4. The organic-inorganic hybrid composition according to item 3 above, wherein the surface modifier has an acidic functional group.
(Configuration 5)
5. The organic-inorganic hybrid composition according to item 4 above, wherein the acidic functional group is at least one acidic functional group selected from the group consisting of a sulfonic acid group, a phosphonic acid group, a phosphinic acid group, and a carboxylic acid group.
(Configuration 6)
6. The organic-inorganic hybrid composition according to any one of items 3 to 5 above, wherein the content of the surface modifier is 1 to 30% by mass based on 100% by mass of the inorganic fine particles (B).
(Configuration 7)
7. The organic-inorganic hybrid composition according to any one of items 1 to 6 above, wherein the thermoplastic resin (A) is an acrylic resin or a polycarbonate resin.
(Configuration 8)
8. The organic-inorganic hybrid composition according to any one of items 1 to 7 above, wherein the inorganic fine particles (B) are ZrO ₂ (zirconium oxide).
(Configuration 9)
9. A molded article obtained by using the organic/inorganic hybrid composition according to any one of items 1 to 8 above.
(Configuration 10)
9. A film or sheet obtained by using the organic-inorganic hybrid composition according to any one of items 1 to 8 above.

The organic-inorganic composite composition of the present invention exhibits good transparency and low dielectric constant by adding a specific amount of inorganic fine particles having a specific particle size.

The photograph in FIG. 1 shows a TEM image of the organic-inorganic hybrid composition prepared in Example 4. The photograph in FIG. 2 shows a TEM image of the organic-inorganic hybrid composition prepared in Comparative Example 4.

The present invention is an organic-inorganic composite composition containing a thermoplastic resin (A) and inorganic fine particles (B), characterized in that, when the entire organic-inorganic composite composition is taken as 100 mass %, the content of the inorganic fine particles (B) is 8 mass % or less, and the average particle diameter of the inorganic fine particles (B) is 1 to 85 nm.

The present invention will be described in more detail below.

<<Thermoplastic resin (A)>>
Specific examples of the thermoplastic resin (A) include polyvinyl chloride resin, polystyrene resin, ABS resin, AS resin, acrylic resin, very low density polyethylene, low density polyethylene resin, linear low density polyethylene resin, medium density polyethylene resin, high density polyethylene resin, very high density polyethylene resin, polypropylene resin, polycarbonate resin, polyphenylene ether resin, nylon 6 resin, nylon 66 resin, aramid resin, polyacetal resin, polyester resin, polysulfone resin, polyacetal resin, polyetherimide resin, polyimide resin, polylactic acid resin, polyether ether ketone resin, polyphenylene sulfide resin, polyamide imide resin, liquid crystal polymer resin, polytetrafluoroethylene resin, polychlorotrifluoroethylene resin, polyvinylidene fluoride resin, vinylidene chloride resin, cyclic polyolefin resin, polyvinyl acetate resin, polyurethane resin, and copolymers and mixtures of various polymeric substances. These thermoplastic resins may be used alone or in combination of two or more.

Among the above thermoplastic resins, polyphenylene ether resin, polyphenylene sulfide resin, polystyrene resin, polyester resin, polycarbonate resin, acrylic resin, and cyclic polyolefin resin are preferred, polyester resin, polycarbonate resin, acrylic resin, and cyclic polyolefin resin are more preferred, and polycarbonate resin and acrylic resin are particularly preferred.

<Polycarbonate resin>
The monomer used in the polycarbonate resin preferably used in the present invention may be any of aromatic diol compounds, aliphatic diol compounds, and alicyclic diol compounds, and examples thereof include the diol compounds described in WO 2004/111106 and WO 2011/021720, and oxyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol. These diol compounds may be used alone or in combination of two or more kinds.

The aromatic diol compound preferably contains a structural unit represented by the following formula (1):

In the above formula (1), R ¹ and R ² are each independently at least one group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, a cycloalkoxy group having 6 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, a nitro group, an aldehyde group, a cyano group, and a carboxyl group. When there are a plurality of ^{R 1} and R ² , they may be the same or different.

Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, etc.

Examples of alkyl groups having 1 to 18 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, and tetradecyl groups. Preferred are alkyl groups having 1 to 6 carbon atoms.

Examples of alkoxy groups having 1 to 18 carbon atoms include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, and octoxy groups. Alkoxy groups having 1 to 6 carbon atoms are preferred.

Examples of the cycloalkyl group having 6 to 20 carbon atoms include a cyclohexyl group, a cyclooctyl group, etc. A cycloalkyl group having 6 to 12 carbon atoms is preferred.

Preferred examples of cycloalkoxy groups having 6 to 20 carbon atoms include cyclohexyloxy groups and cyclooctyloxy groups. Cycloalkoxy groups having 6 to 12 carbon atoms are preferred.

Examples of alkenyl groups having 2 to 10 carbon atoms include methenyl, ethenyl, propenyl, butenyl, and pentenyl groups. Alkenyl groups having 2 to 6 carbon atoms are preferred.

Examples of aryl groups having 6 to 14 carbon atoms include phenyl groups and naphthyl groups. Examples of aryloxy groups having 6 to 14 carbon atoms include phenyloxy groups and naphthyloxy groups.

Examples of aralkyl groups having 7 to 20 carbon atoms include benzyl groups and phenylethyl groups. Examples of aralkyloxy groups having 7 to 20 carbon atoms include benzyloxy groups and phenylethyloxy groups.

e and f are each independently an integer from 1 to 4.

W is a single bond or at least one group selected from the group consisting of groups represented by the following formula (2):

In the above formula (2), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ each independently represent a group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms.

Examples of alkyl groups having 1 to 18 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and dodecyl groups. Preferred are alkyl groups having 1 to 6 carbon atoms.

Aryl groups having 6 to 14 carbon atoms include phenyl and naphthyl groups. These may be substituted. Substituents include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, and butyl groups.

Examples of aralkyl groups having 7 to 20 carbon atoms include benzyl and phenylethyl groups.

R ¹⁹ and R ²⁰ each independently represent at least one group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, a cycloalkoxy group having 6 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, a nitro group, an aldehyde group, a cyano group, and a carboxyl group. When there are a plurality of groups, they may be the same or different.

Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, etc.

Examples of alkyl groups having 1 to 18 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, and tetradecyl groups. Preferred are alkyl groups having 1 to 6 carbon atoms.

Examples of alkoxy groups having 1 to 10 carbon atoms include methoxy, ethoxy, propoxy, butoxy, and pentoxy groups. Alkoxy groups having 1 to 6 carbon atoms are preferred.

Examples of cycloalkyl groups having 6 to 20 carbon atoms include cyclohexyl and cyclooctyl groups. Cycloalkyl groups having 6 to 12 carbon atoms are preferred.

Examples of cycloalkoxy groups having 6 to 20 carbon atoms include cyclohexyloxy and cyclooctyl groups. Cycloalkoxy groups having 6 to 12 carbon atoms are preferred.

Examples of alkenyl groups having 2 to 10 carbon atoms include methenyl, ethenyl, propenyl, butenyl, and pentenyl groups. Alkyl groups having 1 to 6 carbon atoms are preferred.

Examples of aryl groups having 6 to 14 carbon atoms include phenyl groups and naphthyl groups. Examples of aryloxy groups having 6 to 14 carbon atoms include phenyloxy groups and naphthyloxy groups.

Examples of aralkyl groups having 7 to 20 carbon atoms include benzyl groups and phenylethyl groups. Examples of aralkyloxy groups having 7 to 20 carbon atoms include benzyloxy groups and phenylethyloxy groups.

g is an integer from 1 to 10, preferably an integer from 1 to 6. h is an integer from 4 to 7, preferably an integer from 4 to 5.

Examples of aromatic diol compounds represented by the above formula (1) include 4,4'-biphenol, 3,3',5,5'-tetrafluoro-4,4'-biphenol, α,α'-bis(4-hydroxyphenyl)-o-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene (hereinafter sometimes abbreviated as "BPM"), α,α'-bis(4-hydroxyphenyl)-p-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-m-bis(1,1,1,3,3,3-hexafluoroisopropyl)benzene, 1,1- Bis(4-hydroxyphenyl)cyclohexane (hereinafter sometimes abbreviated as "BPZ"), 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (hereinafter sometimes abbreviated as "BPTMC"), 1,1-bis(3-methyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (hereinafter sometimes abbreviated as "BPOCTMC"), 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl) 1,1-bis(3-fluoro-4-hydroxyphenyl)cyclopentane, 1,1-bis(3-fluoro-4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)perfluorocyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 3,3'-dimethyl-4,4'-dihydroxydiphenyl sulfide, 3,3'-dimethyl-4,4'-dihydroxydiphenyl sulfide 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-diphenyl sulfide, 4,4'-dihydroxy-3,3'-diphenyl sulfoxide, 4,4'-dihydroxy-3,3'-diphenyl sulfone, 1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (hereinafter sometimes abbreviated as "BPA"), 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane (hereinafter sometimes abbreviated as "BPA"). (hereinafter sometimes abbreviated as "BPC"), 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane (hereinafter sometimes abbreviated as "BP26XA"), 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxy-3-phenylphenyl)propane, 2,2-bis(3-isopropyl-4-hydroxyphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 4,4-bis(4-hydroxyphenyl) Heptane, 2,2-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)decane, 1,1-bis(3-methyl-4-hydroxyphenyl)decane, 1,1-bis(2,3-dimethyl-4-hydroxyphenyl)decane, 2,2-bis(3-bromo-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)diphenylmethane, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane (hereinafter abbreviated as "BPAF") ), 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 7,7'-dimethyl-6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 7,7'-diphenyl-6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane, 2,2-bis(4-hydroxy-3-methylphenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoro Examples of the aromatic diol compounds include propane, 2,2-bis(3-fluoro-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, and 2,2-bis(3,5-difluoro-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, and 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane. These aromatic diol compounds may be used alone or in combination of two or more.

Aliphatic diol compounds include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-n-butyl-2-ethyl-1, Examples of the aliphatic diol compounds include 3-propanediol, 2,2-diethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexane glycol, 1,2-octyl glycol, 2-ethyl-1,3-hexanediol, 2,3-diisobutyl-1,3-propanediol, 2,2-diisoamyl-1,3-propanediol, and 2-methyl-2-propyl-1,3-propanediol. These aliphatic diol compounds may be used alone or in combination of two or more.

Examples of alicyclic diol compounds include isosorbide, cyclohexanedimethanol, tricyclodecane dimethanol, adamantanediol, pentacyclopentadecanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 3,9-bis(2-hydroxyethyl)-2,4,8,10-tetraoxaspiro(5.5)undecane, 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro(5.5)undecane, 3,9-bis(2-hydroxy-1,1-diethylethyl)-2,4,8,10-tetraoxaspiro(5.5)undecane, and 3,9-bis(2-hydroxy-1,1-dipropylethyl)-2,4,8,10-tetraoxaspiro(5.5)undecane. These alicyclic diol compounds may be used alone or in combination of two or more.

<Production method of polycarbonate resin>
The polycarbonate resin preferably used in the present invention is obtained by reacting the diol compound with a carbonate precursor. The reaction method may include an interfacial polycondensation method, a melt transesterification method, a solid-phase transesterification method of a carbonate prepolymer, and a ring-opening polymerization method of a cyclic carbonate compound. In the case of interfacial polycondensation, a terminal terminator of a monohydric phenol is usually used. In addition, it may be a branched polycarbonate obtained by polymerizing a trifunctional component, or a copolymerized polycarbonate obtained by copolymerizing an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid, and a vinyl monomer.

In reactions using, for example, phosgene as a carbonate precursor, the reaction is usually carried out in the presence of an acid binder and a solvent. The acid binder may be, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, or an amine compound such as pyridine. The solvent may be, for example, a halogenated hydrocarbon such as methylene chloride or chlorobenzene. A catalyst such as a tertiary amine or a quaternary ammonium salt may also be used to promote the reaction. In this case, the reaction temperature is usually 0 to 40°C, and the reaction time is several minutes to 5 hours.

The transesterification reaction using, for example, a carbonic acid diester as a carbonate precursor is carried out by heating and stirring a predetermined proportion of aromatic dihydroxy components with a carbonic acid diester under an inert gas atmosphere, and distilling off the resulting alcohol or phenol. The reaction temperature varies depending on the boiling point of the resulting alcohol or phenol, but is usually in the range of 120 to 300°C. The reaction is completed by reducing the pressure from the beginning and distilling off the resulting alcohol or phenol. In order to promote the reaction, a catalyst usually used in transesterification reactions can also be used. Examples of carbonic acid diesters used in the transesterification reaction include diphenyl carbonate, dinaphthyl carbonate, bis(diphenyl)carbonate, dimethyl carbonate, diethyl carbonate, and dibutyl carbonate. Of these, diphenyl carbonate is particularly preferred.

Monofunctional phenols that are commonly used as end terminators can be used. In particular, in the case of reactions using phosgene as a carbonate precursor, monofunctional phenols are commonly used as end terminators to adjust molecular weight, and the resulting polycarbonate resin has excellent thermal stability compared to those that are not, since the ends are blocked with groups based on monofunctional phenols. Specific examples of the monofunctional phenols include phenol, m-methylphenol, p-methylphenol, m-propylphenol, p-propylphenol, 1-phenylphenol, 2-phenylphenol, p-tert-butylphenol, p-cumylphenol, isooctylphenol, and p-long-chain alkylphenol.

Polycarbonate resins can be copolymerized with fatty acids as needed. Examples include 1,10-dodecanedioic acid (DDDA), adipic acid, hexanedioic acid, isophthalic acid, 1,3-benzenedicarboxylic acid, terephthalic acid, 1,4-benzenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 3-hydroxybenzoic acid (mHBA), and 4-hydroxybenzoic acid (pHBA).

The polycarbonate resin includes polyester carbonates copolymerized with aromatic or aliphatic (including alicyclic) bifunctional carboxylic acids. The aliphatic bifunctional carboxylic acids are preferably α,ω-dicarboxylic acids. Examples of the aliphatic bifunctional carboxylic acids include linear saturated aliphatic dicarboxylic acids such as sebacic acid (decanedioic acid), dodecanedioic acid, tetradecanedioic acid, octadecanedioic acid, and icosane diacid, as well as alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. These carboxylic acids may be copolymerized to the extent that the purpose is not hindered. The polycarbonate resin of the present invention may also be copolymerized with a structural unit containing a polyorganosiloxane unit, if necessary.

Polycarbonate resins can be copolymerized with a structural unit containing a trifunctional or higher polyfunctional aromatic compound to produce branched polycarbonates, if necessary. Suitable examples of trifunctional or higher polyfunctional aromatic compounds used in branched polycarbonates include trisphenols such as 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2, 2,4,6-trimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1-tris(4-hydroxyphenyl)ethane, 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane, 2,6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, and 4-{4-[1,1-bis(4-hydroxyphenyl)ethyl]benzene}-α,α-dimethylbenzylphenol. Of these, 1,1,1-tris(4-hydroxyphenyl)ethane is preferred. The structural units derived from such polyfunctional aromatic compounds preferably account for 0.03 to 1.5 mol%, more preferably 0.1 to 1.2 mol%, and particularly preferably 0.2 to 1.0 mol%, of the total of 100 mol% including the structural units from other divalent components.

The branched structural unit may be derived not only from a polyfunctional aromatic compound, but also from a side reaction occurring during a polymerization reaction by a melt transesterification method without using a polyfunctional aromatic compound. The proportion of such branched structures can be calculated by ^1H -NMR measurement.

(viscosity average molecular weight)
The viscosity average molecular weight of the polycarbonate resin preferably used in the present invention is preferably 15,000 to 40,000, more preferably 16,000 to 39,000, and even more preferably 17,000 to 38,000. Within the above range, practical mechanical strength is easily obtained in many fields, and since the resin has a suitable melt viscosity during molding, problems such as thermal deterioration are suppressed, and the difference in melt viscosity with the polycarbonate resin to be mixed as required is small, resulting in good kneadability. Furthermore, the efficiency of the water washing step during resin production is good, resulting in excellent productivity.

The viscosity average molecular weight of the polycarbonate resin in the present invention is determined by first determining the specific viscosity (η _SP ) calculated by the following formula using an Ostwald viscometer from a solution in which 0.7 g of the resin is dissolved in 100 ml of methylene chloride at 20° C.:
Specific viscosity (η _SP )=(t−t ₀ )/t ₀
[ _t0 is the number of seconds that methylene chloride falls, and t is the number of seconds that the sample solution falls]
The viscosity average molecular weight Mv was calculated from the determined specific viscosity (η _SP ) according to the following formula.
η _SP /c = [η] + 0.45 × [η] ² c (where [η] is the intrinsic viscosity)
[η]=1.23×10 ⁻⁴ Mv ^0.83
c=0.7

(Glass transition temperature: Tg)
The glass transition temperature (Tg) of the polycarbonate resin is preferably 90 to 180° C., more preferably 100 to 160° C. If the Tg is within the above range, the heat resistance stability and moldability are good when used as a molded article, which is preferable. The glass transition temperature (Tg) is measured using a 2910-type DSC manufactured by TA Instruments Japan Ltd. at a heating rate of 20° C./min.

<Acrylic resin>
Examples of monomers suitable for use in the acrylic resin of the present invention include the following compounds. For example, methyl methacrylate, methyl acrylate, methacrylic acid, acrylic acid, benzyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, Examples of the acrylate include acrylate, acrylic (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-(meth)acroyloxyethyl succinate, 2-(meth)acroyloxyethyl maleate, 2-(meth)acroyloxyethyl phthalate, 2-(meth)acryloyloxyethyl hexahydrophthalate, pentamethylpiperidyl (meth)acrylate, tetramethylpiperidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, cyclopentyl methacrylate, cyclopentyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, cycloheptyl methacrylate, cycloheptyl acrylate, cyclooctyl methacrylate, cyclooctyl acrylate, cyclododecyl methacrylate, and cyclododecyl acrylate.

These may be polymerized alone or in combination of two or more. In particular, it is preferable to use methyl methacrylate and/or methyl acrylate. As monomer components, it is preferable to use 50 to 99 mol% methyl methacrylate and 1 to 50 mol% methyl acrylate, more preferably 60 to 99 mol% methyl methacrylate and 1 to 40 mol% methyl acrylate, and even more preferably 70 to 99 mol% methyl methacrylate and 1 to 30 mol% methyl acrylate. If the monomer component contains more than 99 mol% methyl methacrylate, the thermal decomposition resistance is poor and molding defects such as silver may occur during molding. If the monomer component contains less than 50 mol% methyl methacrylate, the heat distortion temperature may decrease. In addition, other monomers that can be polymerized with these acrylic monomers, such as olefin monomers and vinyl monomers, may be used in combination at 0 to 30 mass%.

(molecular weight)
The molecular weight of the acrylic resin is not particularly limited, but as long as the weight average molecular weight is in the range of 30,000 to 300,000, a molded product having excellent mechanical properties and heat resistance can be provided without causing appearance defects such as uneven flow during molding.

(Glass transition temperature: Tg)
The glass transition temperature (Tg) of the acrylic resin preferably used in the present invention is preferably 90 to 150° C., more preferably 95 to 145° C., and even more preferably 100 to 140° C. A Tg of 90 to 150° C. is preferable since it provides good heat resistance stability and moldability. The glass transition temperature (Tg) is measured using a 2910 DSC manufactured by TA Instruments Japan Ltd. at a heating rate of 20° C./min.

<<Inorganic fine particles>>
The inorganic fine particles used in the present invention are not particularly limited, but examples thereof include _ZrO2 (zirconium oxide), _TiO2 (titanium oxide), _SnO2 (tin oxide), _SiO2 (silicon oxide), _Al2O3 (aluminum oxide), ZnO ₍ zinc oxide), MgO (magnesium oxide), etc. Among these, _ZrO2 (zirconium oxide) is preferable.

In addition, in the present invention, when the entire organic-inorganic composite composition is taken as 100% by mass, the content of inorganic fine particles is 8% by mass or less, preferably 6% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, particularly preferably 2% by mass or less, and most preferably 1% by mass or less. The lower limit is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, particularly preferably 0.2% by mass or more, and most preferably 0.3% by mass or more. If the content of inorganic fine particles exceeds 8% by mass, it is not preferable because it adversely affects transparency and low dielectric constant.

<Surface Modifier>
The inorganic fine particles may be modified with a surface modifier as necessary. The surface modifier of the inorganic fine particles in the present invention is not particularly limited as long as it can ensure the dispersibility of the inorganic fine particles in the thermoplastic resin to be composited, but it is preferable that it has an acidic functional group, and it is particularly preferable that it has an acidic functional group of any of sulfonic acid group, phosphonic acid group, phosphinic acid group, and carboxylic acid group because it is excellent in surface modification. Representative specific examples of the surface modifier are shown below, but the surface modifier of the present invention is not limited thereto. They may be used alone, or a plurality of types may be mixed and used. It is desirable to select and use appropriately for the purpose of improving the dispersibility of the fine particles in the thermoplastic resin or not adversely affecting the dielectric constant.

Examples of sulfonic acids include alkyl sulfonic acids such as butanesulfonic acid, hexanesulfonic acid, and dodecanesulfonic acid, and aryl sulfonic acids such as benzenesulfonic acid, methylbenzenesulfonic acid, and dodecylbenzenesulfonic acid. Among these, aryl sulfonic acids are preferred in view of their dispersibility in resins and their effect of improving the refractive index.

Examples of phosphonic acids include alkyl phosphonic acids such as propane phosphonic acid, and aryl phosphonic acids such as benzene phosphonic acid. Among these, aryl phosphonic acids are preferred in view of their dispersibility in resins and their effect of improving the refractive index.

Examples of phosphinic acids include alkyl phosphinic acids such as dimethylphosphinic acid, diethylphosphinic acid, and di(2-ethylhexyl)phosphinic acid, and aryl phosphinic acids such as phenylphosphinic acid and diphenylphosphinic acid. Among these, aryl phosphinic acids are preferred because of their dispersibility in resins and solvents, with phenylphosphinic acid and diphenylphosphinic acid being more preferred, and diphenylphosphinic acid being particularly preferred.

Examples of the carboxylic acid include alkyl carboxylic acids such as butanoic acid, isobutanoic acid, methacrylic acid, hexanoic acid, octanoic acid, oleic acid, linoleic acid, and lauric acid, and aryl carboxylic acids such as benzoic acid, hydroxybenzoic acid, and phenoxybenzoic acid. Among these, in consideration of dispersibility in resins and solvents, aryl carboxylic acids are preferred, phenoxybenzoic acid having a phenoxy group at the ortho, meta, or para position is more preferred, and paraphenoxybenzoic acid is particularly preferred.

<Surface modification method>
The surface modification of inorganic fine particles in the present invention is carried out, for example, by the following process. That is, a surface modifier having an acidic functional group is added to a mixture of a transparent aqueous dispersion in which hydrophilic inorganic fine particles having an average particle size of about 20 nm or less are dispersed, and methanol, and then the water and methanol are removed by azeotropy and replaced with an organic solvent such as toluene, dichloromethane, or chloroform to prepare a dispersion in which the surface-modified inorganic fine particles are dispersed. The solvent is then completely distilled off to obtain a white powder of the surface-modified inorganic fine particles.

In inorganic microparticles modified with a surface modifier, the content of the surface modifier is preferably 1 to 30% by mass, more preferably 5 to 28% by mass, and even more preferably 10 to 25% by mass, relative to the inorganic microparticles, taking into consideration the effect on dispersibility in thermoplastic resins and dielectric properties. From the viewpoint of dispersibility in thermoplastic resins, the higher the content of the surface modifier, the better. It is desirable to adjust the content of the surface modifier appropriately depending on the dispersibility and dielectric properties.

<Method of producing organic-inorganic composite composition>
The method for blending inorganic fine particles with a thermoplastic resin is not particularly limited, but the following methods can be mentioned.

(Melting and kneading method)
In this method, a thermoplastic resin and inorganic fine particles are dry-blended, and then melt-kneaded to obtain an organic-inorganic composite composition.

(Solvent dispersion method)
In this method, a thermoplastic resin and inorganic fine particles are dissolved or dispersed in a solvent and mixed, and then the solvent is evaporated to obtain an organic-inorganic composite composition.

(Polymerization dispersion method)
This method comprises dispersing inorganic fine particles in a polymerization reaction liquid containing a monomer, and then carrying out a normal polymerization operation to obtain an organic-inorganic hybrid composition in which the inorganic fine particles are uniformly dispersed.

Among these, the solvent dispersion method is preferred from the viewpoint of improving the dispersibility of the fine particles in the obtained organic-inorganic composite composition and from the viewpoint of productivity. The composition obtained by the solvent dispersion method may be directly molded into a cast film, or may be melt-processed by extrusion, molding, or the like to be molded into a molded product.

In the case of the solvent dispersion method, the solvent to be used may be appropriately selected from those that dissolve or disperse the thermoplastic resin and inorganic fine particles, and the type of the solvent is not particularly limited. For example, the solvent is selected taking into consideration the solubility parameters and polarity of the thermoplastic resin and inorganic fine particles. For example, methylene chloride, chloroform, toluene, tetrahydrofuran, etc. can be used as the solvent.

The inorganic fine particles may be mixed as a solid into a solution in which a thermoplastic resin is dissolved in a solvent, or the inorganic fine particles may be dispersed in advance in a solvent to form a dispersion, which is then mixed.

The amount of solvent used is not particularly limited, but may be selected so that the concentration is such that the thermoplastic resin and inorganic fine particles can be completely dissolved or dispersed. For example, it is preferable to use 100 to 10,000 parts by mass of the solvent per 100 parts by mass of the thermoplastic resin or inorganic fine particles.

The organic-inorganic composite composition of the present invention may contain additives such as heat stabilizers, plasticizers, light stabilizers, polymerized metal deactivators, flame retardants, lubricants, antistatic agents, surfactants, antibacterial agents, UV absorbers, and release agents, as necessary.

(Molding method)
The organic/inorganic composite composition of the present invention can be molded by a general molding method for thermoplastic resins, such as injection molding, extrusion molding, compression molding, and solvent casting. The organic/inorganic composite composition of the present invention has excellent transparency and dielectric properties, and can be used as various molded products. In particular, it can be advantageously used as a molded product suitable for optical components such as optical lenses, optical disks, liquid crystal panels, optical cards, sheets, films, optical fibers, connectors, evaporated plastic reflectors, and displays, electric/electronic components such as front panels and exteriors of personal computers and mobile phones, and film antennas, automotive applications such as automobile headlamps and windows, or functional material applications, and is particularly suitable for optical components and electric/electronic components that take advantage of the transparency and low dielectric properties.

(Particle size)
In the organic-inorganic hybrid composition, the inorganic fine particles have an average particle size of 1 to 85 nm, preferably 2 to 80 nm, more preferably 3 to 75 nm, further preferably 5 to 72 nm, and particularly preferably 10 to 70 nm. If the average particle size of the inorganic fine particles exceeds the upper limit, it is not preferable because it adversely affects transparency and low dielectric constant.

The present invention will be further explained below with reference to examples, but the present invention is not limited thereto. In the following examples and comparative examples, the methods for measuring the various properties are as follows.

<Evaluation method>
(viscosity average molecular weight)
The specific viscosity (η _SP ) calculated by the following formula was determined using an Ostwald viscometer from a solution of 0.7 g of a sample dissolved in 100 ml of methylene chloride at 20° C.
Specific viscosity (η _SP )=(t−t ₀ )/t ₀
[ _t0 is the number of seconds that methylene chloride falls, and t is the number of seconds that the sample solution falls]
The viscosity average molecular weight Mv was calculated from the determined specific viscosity (η _SP ) according to the following formula.
η _SP /c = [η] + 0.45 × [η] ² c (where [η] is the intrinsic viscosity)
[η]=1.23×10 ⁻⁴ Mv ^0.83
c=0.7

(Glass Transition Temperature (Tg))
Using 8 mg of a sample, a thermal analysis system DSC-2910 manufactured by TA Instruments was used to perform the measurement in accordance with JIS K7121 under the conditions of a nitrogen atmosphere (nitrogen flow rate: 40 ml/min) and a temperature rise rate of 20° C./min.

(Total light transmittance, haze)
The total light transmittance and haze of the obtained film were measured using a haze meter (product name: NDH-3000, manufactured by Nippon Denshoku Industries Co., Ltd.).

(Average particle size)
The film of the organic-inorganic composite composition was cut using a microtome (EM UC6, manufactured by Leica Microsystems) to prepare ultrathin sections, which were attached to a grid (EM FINE GRID No. 2632 F-200-CU 100PC/CA, manufactured by JEOL Ltd.) and observed at an accelerating voltage of 200 kV using a transmission electron microscope TEM JEM-2100, manufactured by JEOL Ltd. The observation magnification was 10,000 times.

The obtained micrographs were subjected to particle analysis using image analysis software Win ROOF Ver. 6.6 (Mitani Shoji Co., Ltd.) to obtain the average size and particle size distribution (frequency distribution) of the inorganic fine particles in the sample slices. Here, the maximum major axis (the length when any two points on the outer contour of the particle are selected so that the distance between them is the maximum) was used as the size of each particle. A similar analysis was performed on five sample slices, and the average value was used as the value for each sample.

(Dielectric constant and dielectric loss tangent)
The film of the organic-inorganic composite composition was measured for the relative dielectric constant and the dielectric loss tangent at 1, 5 and 10 GHz using a KEYCOM dielectric constant meter (network analyzer: Anritsu MS4622B) with a cavity resonator.

<Polycarbonate resin>
PC-1: A reactor equipped with a thermometer, a stirrer and a reflux condenser was charged with 4179 parts of 25% aqueous sodium hydroxide solution and 9404 parts of ion-exchanged water, to which 1,988 parts of 2,2-bis(4-hydroxyphenyl)propane (BPA) and 3.98 parts of hydrosulfite (manufactured by Wako Pure Chemical Industries, Ltd.) were dissolved, and then 7,401 parts of methylene chloride was added, and 1,000 parts of phosgene was blown in over about 70 minutes at 15 to 25° C. with stirring. After completion of the blowing in of phosgene, 697 parts of an aqueous 25% sodium hydroxide solution and 16.9 parts of p-tert-butylphenol were added, stirring was resumed, and after emulsification, 2.20 parts of triethylamine was added, and the mixture was further stirred at 28 to 33° C. for 1 hour to complete the reaction.

After the reaction was completed, the organic phase was separated, diluted with methylene chloride and repeatedly washed with water. When the washings became neutral, it was washed with acidic hydrochloric acid water. It was then repeatedly washed with ion-exchanged water, and when the conductivity of the aqueous phase became almost the same as that of the ion-exchanged water, it was placed in a kneader filled with warm water and the methylene chloride was evaporated while stirring. After dehydration, it was dried at 100°C for 12 hours in a hot air circulation dryer to obtain a resin powder. The viscosity average molecular weight of the obtained resin was 37,500 and the glass transition temperature was 155°C.

PC-2: 8,523 parts of ion-exchanged water and 3,787 parts of 25% sodium hydroxide solution were placed in a reactor equipped with a thermometer, stirrer, and reflux condenser, and 901 parts of BPA and 1,010 parts of 2,2-bis(4-hydroxy-3-methylphenyl)propane (BPC) as dihydric phenols and 5.73 parts of hydrosulfite were dissolved therein. Then, 6,708 parts of methylene chloride were added, and 1,000 parts of FH were blown in over 70 minutes at 16-24°C while stirring. 631 parts of 25% sodium hydroxide solution were added, and 45.0 parts of p-tert-butylphenol were added as a terminal terminator. The mixture was stirred to an emulsified state, and then stirred vigorously again. With such stirring, 2.0 parts of triethylamine were added when the reaction liquid was at 28°C, and the reaction was terminated by continuing to stir at a temperature of 26-31°C for 1 hour. The subsequent operations were the same as in Example 1, and a resin powder was obtained. The viscosity average molecular weight of the resulting resin was 20,000 and the glass transition temperature was 130°C.

PC-3: 22,380 parts of ion-exchanged water and 3,844 parts of 48% sodium hydroxide solution were placed in a reactor equipped with a thermometer, stirrer, and reflux condenser, and 3,984 parts of BPC as a dihydric phenol and 7.53 parts of hydrosulfite were dissolved therein. Then, 13,210 parts of methylene chloride were added, and 2,000 parts of FH were blown in over 60 minutes at 16-24°C while stirring. 640 parts of 48% sodium hydroxide solution were added, and 93.2 parts of p-tert-butylphenol were added as a terminal terminator. The mixture was stirred to an emulsified state, and then stirred vigorously again. With such stirring, 3.24 parts of triethylamine were added when the reaction liquid was at 28°C, and the reaction was terminated by continuing to stir at a temperature of 26-31°C for 1 hour. The subsequent operations were the same as in Example 1, and a resin powder was obtained. The viscosity average molecular weight of the obtained resin was 26,900, and the glass transition temperature was 120°C.

<Acrylic resin>
PMMA-1: Mitsubishi Rayon Acrypet VH-001 (a copolymer acrylic resin of methyl methacrylate and methyl acrylate).

<Inorganic fine particles>
NP-1: 3.84 g of paraphenoxybenzoic acid was placed in a 2 L eggplant flask equipped with a stirrer tip as a surface modifier, and 300 mL of methanol and 700 mL of chloroform were added and dissolved. Next, 37.2 g of _ZrO2 aqueous dispersion (SZR-W manufactured by Sakai Chemical Industry Co., Ltd.) was dropped over 15 minutes. The mixture was stirred at room temperature for 1 hour, and the solvent was distilled off to about 200 mL using a rotary evaporator. The distillation was performed by reducing the pressure to a level at which bumping did not occur in the liquid phase. 300 mL of methanol and 700 mL of chloroform were further added to the mixture to make a transparent dispersion with no interface again, and the solvent was distilled off again to about 200 mL. This operation was repeated three times to obtain a powdery solid.

500 mL of methylene chloride was added to the obtained solid to obtain a transparent dispersion with no interface again, and the solvent was distilled off until the volume was about 100 mL. This operation was repeated three times to replace the water/methanol/chloroform mixed solvent with methylene chloride alone, obtaining a methylene chloride dispersion of ZrO2 _fine particles. Furthermore, this methylene chloride dispersion was vacuum dried at room temperature for 24 hours to remove the methylene chloride, and then further dried at 120°C for 48 hours to obtain a powder of surface-modified _ZrO2 (ZrO2 _fine particles containing 24% by mass of surface modifier).

NP-2: A surface-modified _ZrO2 powder was obtained in the same manner as NP-1, except that 1.34 g of diphenylphosphinic acid was used as the surface modifier ( _ZrO2 fine particles containing 10% by mass of the surface modifier).

<Production of Organic-Inorganic Composite Composition>
The thermoplastic resin and the inorganic particles were mixed by a solvent dispersion method (A) or a melt kneading method (B), and the film was formed by a solvent casting method (C) or a melt extrusion method (D).

[Example 1]
A methylene chloride solution of PC-1 as a thermoplastic resin and a methylene chloride dispersion of NP-1 as inorganic fine particles were prepared, and then the two were mixed to obtain a uniform PC-1/NP-1 methylene chloride dispersion (solvent dispersion method: A). Next, the PC-1/NP-1 methylene chloride dispersion was dried at 25°C for 12 hours and 80°C for 4 hours to distill off the methylene chloride, and then further dried at 100°C for 24 hours to obtain a cast film of the organic-inorganic composite composition (solvent cast method: C). Various evaluations were performed using the cast film, and the results are shown in Table 1.

[Example 2]
A methylene chloride solution of PC-1 as a thermoplastic resin and a methylene chloride dispersion of NP-1 as inorganic fine particles were prepared, and then the two were mixed to obtain a uniform PC-1/NP-1 methylene chloride dispersion (solvent dispersion method: A). Next, this solution was dropped into warm water in a kneader with an isolation chamber having a foreign matter outlet in the bearing section, and flaked while distilling off methylene chloride, and the liquid-containing flakes were subsequently crushed and dried to obtain a powder. The powder was melt-kneaded using a 15 mmφ twin-screw extruder (KZW15-25MG) manufactured by Technobel Co., Ltd., with both the cylinder and die temperatures at 350°C, to obtain pellets of an organic-inorganic composite composition of PC-1/NP-1. The obtained pellets were dried at 90°C for 6 hours using a hot air circulation dryer. A 15 mm diameter twin-screw extruder manufactured by Technovel Co., Ltd. was equipped with a T-die with a width of 150 mm and a lip width of 500 μm and a film take-up device, and the pellets obtained were molded into a film at 350° C. to obtain an extruded film (melt extrusion method: D). Various evaluations were performed on the obtained film. The evaluation results are shown in Table 1.

[Example 3]
The same procedure as in Example 1 was carried out except that PC-2 was used as the thermoplastic resin. The results are shown in Table 1.

[Example 4]
The same procedure as in Example 1 was carried out, except that PC-2 was used as the thermoplastic resin and NP-2 was used as the inorganic fine particles. The results are shown in Table 1.

[Example 5]
The same operation as in Example 4 was carried out, except that the content of the inorganic fine particles was changed to 5.0% by mass. The results are shown in Table 1.

[Example 6]
The same procedure as in Example 1 was carried out except that PC-3 was used as the thermoplastic resin. The results are shown in Table 1.

[Example 7]
The same procedure as in Example 1 was carried out except that PMMA-1 was used as the thermoplastic resin. The results are shown in Table 1.

[Comparative Example 1]
A methylene chloride solution of PC-1 was prepared as a thermoplastic resin, and the solution was dried at 25° C. for 12 hours and at 80° C. for 4 hours to remove the methylene chloride, and then further dried at 100° C. for 24 hours to obtain a cast film. Various evaluations were carried out using the cast film, and the results are shown in Table 1.

[Comparative Example 2]
After dry blending pellets of PC-1 as a thermoplastic resin and powder of NP-1 as inorganic fine particles, the mixture was melt-kneaded at cylinder and die temperatures of 350°C using a 15mmφ twin-screw extruder (KZW15-25MG) manufactured by Technovel Co., Ltd. to obtain pellets of an organic-inorganic composite composition of PC-1/NP-1 (melt-kneading method: B). The obtained pellets were dried at 90°C for 6 hours using a hot air circulation dryer. A T-die with a width of 150 mm and a lip width of 500 μm and a film take-up device were attached to a 15mmφ twin-screw extruder manufactured by Technovel Co., Ltd., and the obtained pellets were molded into a film at 350°C to obtain an extruded film. Various evaluations were performed on the obtained film. The evaluation results are shown in Table 1.

[Comparative Example 3]
Except for using PC-2 as the thermoplastic resin, the same procedure as in Comparative Example 1 was carried out. The results are shown in Table 1.

[Comparative Example 4]
PC-2 was used as the thermoplastic resin, and the melt mixing temperature and film forming temperature were set at 280°C.
The same operation as in Comparative Example 2 was carried out except for the above. The results are shown in Table 1.

[Comparative Example 5]
The same operations as in Example 1 were carried out except that PC-2 was used as the thermoplastic resin and the content of the inorganic fine particles was changed to 10.0 mass %. The results are shown in Table 1.

[Comparative Example 6]
Except for using PC-3 as the thermoplastic resin, the same procedure as in Comparative Example 1 was carried out. The results are shown in Table 1.

[Comparative Example 7]
Except for using PMMA-1 as the thermoplastic resin, the same procedure as in Comparative Example 1 was carried out. The results are shown in Table 1.

The organic-inorganic composite compositions in which the particle size of the inorganic fine particles is relatively small as in Examples 1 to 7 exhibited a low dielectric constant compared to the case of a single thermoplastic resin as in Comparative Examples 1, 3, 6, and 7. On the other hand, when the particle size of the inorganic fine particles is relatively large as in Comparative Examples 2 and 4, or when the content of the inorganic fine particles is high as in Comparative Example 5, the low dielectric constant was not exhibited and the transparency was also deteriorated.

Figure 1 shows a TEM image of the organic-inorganic composite composition obtained in Example 4. The composition had high transparency and the inorganic fine particles were uniformly dispersed. On the other hand, Figure 2 shows a TEM image of the organic-inorganic composite composition obtained in Comparative Example 4. The composition had low transparency and the inorganic fine particles were aggregated.

The organic-inorganic composite composition of the present invention is excellent in that it exhibits a low dielectric constant without impairing the inherent transparency of thermoplastic resins by adding a very small amount of inorganic fine particles of a specific particle size. Therefore, molded articles, films, and sheets obtained using the present invention can be used in a variety of fields.

Claims (6)

The organic-inorganic composite composition contains a thermoplastic resin (A) and inorganic fine particles (B), the thermoplastic resin (A) being an acrylic resin or a polycarbonate resin, the polycarbonate resin being a polycarbonate resin obtained by using, as an aromatic diol, 2,2-bis(4-hydroxyphenyl)propane or 2,2-bis(4-hydroxy-3-methylphenyl)propane either alone or in combination, and the inorganic fine particles (B) being ZrO ₂ (zirconium oxide), TiO ₂ (titanium oxide), SnO ₂ (tin oxide), SiO ₂ (silicon oxide), Al ₂ O ₃ the inorganic fine particles (B) are at least one selected from the group consisting of aluminum oxide, zinc oxide, and magnesium oxide; the inorganic fine particles (B) are modified with a surface modifier , the surface modifier having an acidic functional group; when the entire organic-inorganic hybrid composition is taken as 100 mass%, the content of the inorganic fine particles (B) is 6 mass% or less and 0.01 mass% or more; and the average particle diameter of the inorganic fine particles (B) in the organic-inorganic hybrid composition is 1 to 85 nm. 2. The organic-inorganic hybrid composition according to claim 1 , wherein the acidic functional group is at least one acidic functional group selected from the group consisting of a sulfonic acid group, a phosphonic acid group, a phosphinic acid group, and a carboxylic acid group. 3. The organic-inorganic hybrid composition according to claim 1 , wherein the content of the surface modifier is 1 to 30% by mass relative to 100% by mass of the inorganic fine particles (B). 4. The organic-inorganic hybrid composition according to claim 1 , wherein the inorganic fine particles (B) are ZrO ₂ (zirconium oxide). A molded article obtained by using the organic/inorganic hybrid composition according to any one of claims 1 to 4 . A film or sheet obtained by using the organic/inorganic hybrid composition according to any one of claims 1 to 4 .