JP2000053871A - Resin composition and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin compsn. which contains a filler or layered silicate having a small particle size and homogeneously dispersed therein by mixing a thermoplastic resin with an inorg. filler under contact with a supercritical fluid. SOLUTION: This resin compsn. is prepd. by mixing 100 pts.wt. thermoplastic resin with an inorg. filler in an amt. of 80-0.01 wt.% of the compsn. and 0.05-10 pts.wt. olefin compd. having a carboxylic anhydride group under contact with carbon dioxide or the like which becomes a supercritical fluid at a temp. in the range from the m.p. of the resin to its decomposition temp. in an amt. of the fluid of 0.01-30 wt.% of the compsn. Examples of the thermoplastic resin are a polyamide resin, a polyester resin, and a polyarylene sulfide resin. The inorg. filler is a fibrous one (e.g. glass fibrs or steel fibres), a powdery or platy one (e.g. tale or mica), or a layered silcate (e.g. montmorillonite), and 0.01-20 wt.% coupling agent (e.g. a silane compd.) is added to the filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition in which an inorganic filler is dispersed in a thermoplastic resin without agglomeration, has excellent mechanical and thermal properties, and has excellent appearance of a molded article, and its production. About the method.

[0002]

2. Description of the Related Art It is well known that the strength, rigidity and heat resistance of a thermoplastic resin are increased by adding an inorganic filler. However, when the particle size of the inorganic filler to be used is extremely small, there is a problem that the particles aggregate, the dispersion in the thermoplastic resin becomes poor, and the impact resistance is impaired. In recent years, attempts have been made to improve the mechanical strength and rigidity by finely dispersing a layered silicate on the order of nanometers in a polyamide which is a thermoplastic engineering resin. Although the rigidity of the clay-polyamide composite is greatly improved, it is necessary for the layered silicate (clay) to be dispersed in the polyamide in a substantially monolayer having a thickness of about 1 nm. However, secondary agglomeration usually occurs only by mixing and kneading the layered silicate and the thermoplastic resin, and it is difficult to uniformly disperse the resin in the resin. Japanese Patent Application Laid-Open No. 8-12881 has been examining an attempt to obtain a uniform dispersion by using an interlayer compound having a layered silicate as a host and a specific quaternary ammonium salt as a guest. There is a demand for improved mechanical properties. Also, Japanese Patent Application Laid-Open No. 8-151449
Japanese Patent Application Laid-Open No. 9-48856 and Japanese Patent Application Laid-Open No. 9-48856 disclose a method in which a clay mineral is swelled with a solvent, then melt-kneaded with a resin, and a vent port provided in an extruder is kept at a reduced pressure to remove the solvent. Although an attempt to obtain a dispersion is disclosed, there is a problem that the process is complicated due to the use of a solvent, and a normal solvent has a function of swelling a layered silicate, but a thermoplastic resin is used. Has a problem that it does not have a sufficient effect.

[0003]

Therefore, the present invention solves the above-mentioned problems, that is, it uniformly disperses inorganic fillers, particularly fillers having a small particle size, and layered silicates without agglomeration in a thermoplastic resin. It is an object to obtain a resin composition obtained by the method.

[0004]

The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that inorganic fillers, especially fillers having a small particle size and layered silicates, can be used as thermoplastic resins. By applying a supercritical low molecule, that is, a supercritical fluid during dispersion, a uniform dispersion state that cannot be obtained due to secondary aggregation under ordinary kneading conditions can be achieved, and as a result, The present inventors have found that a resin composition having excellent mechanical properties can be obtained, and have reached the present invention.

That is, the present invention is a resin composition obtained by bringing (A) a thermoplastic resin and (B) an inorganic filler into contact with (C) a supercritical fluid and kneading them, and a method for producing the same.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The thermoplastic resin (A) in the present invention may be any resin which can be plastically processed by heating, regardless of its amorphous, crystalline, or liquid crystal properties. Preferred examples of the (A) thermoplastic resin include polyester resin, polyamide resin, polyarylene sulfide resin, polyacetal resin, ABS resin, polyphenylene oxide resin, polycarbonate resin, polystyrene resin, polyolefin resin, and acrylic resin. May be used in combination of two or more. Among them, polyester resin, polyamide resin and polyarylene sulfide resin can be particularly preferably used.

[0008] The polyester resin referred to herein is a thermoplastic polyester having an aromatic ring in a chain unit of the polymer. Specifically, usually, an aromatic dicarboxylic acid (or an ester-forming derivative thereof) and a diol ( Or an ester-forming derivative thereof) and / or a polymer or copolymer obtained by a condensation reaction containing hydroxycarboxylic acid as a main component. These may be liquid crystalline or non-liquid crystalline.

Specific examples of preferred polyester resins in the present invention include polyethylene terephthalate, polypropylene terephthalate, and non-liquid crystalline ones.
Polybutylene terephthalate, polyhexylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, polybutylene-2,6-naphthalenedicarboxylate, polyethylene-1,2-bis (phenoxy) ethane-4,4'-dicarboxy In addition to the rate, polyethylene isophthalate / terephthalate, polybutylene isophthalate / terephthalate, polybutylene terephthalate / decanedicarboxylate, polyethylene-4,4'-dicarboxylate / terephthalate and the like can be mentioned.

As the liquid crystalline compound, a polyester forming an anisotropic molten phase comprising a structural unit selected from an aromatic oxycarbonyl unit, an aromatic dioxy unit, an aromatic dicarbonyl unit, an ethylenedioxy unit and the like can be used. Can be mentioned.

The aromatic oxycarbonyl unit includes, for example, p-hydroxybenzoic acid, 6-hydroxy-2-
Examples of the structural unit generated from naphthoic acid and the aromatic dioxy unit include, for example, structural units generated from 4,4′-dihydroxybiphenyl, hydroquinone and t-butylhydroquinone, and examples of the aromatic dicarbonyl unit include terephthalic acid , Isophthalic acid, 2,6
Examples of the structural unit and aromatic iminooxy unit generated from -naphthalenedicarboxylic acid include a structural unit generated from 4-aminophenol.

Particularly preferred examples of the polyester resin include polybutylene terephthalate, polyethylene terephthalate, and polyethylene-2,6-naphthalenedicarboxylate. These polyester resins can be used for improving moldability, heat resistance, toughness, surface properties and the like. It is also practically suitable to use it as a mixture depending on the required characteristics.

The polyamide resin is a polyamide containing amino acids, lactams or diamines and dicarboxylic acids as main raw materials. Representative examples of the raw materials include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and paraaminomethylbenzoic acid; lactams such as ε-caprolactam and ω-laurolactam; tetramethylenediamine; Methylenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4
-/ 2,4,4-trimethylhexamethylenediamine,
5-methylnonamethylenediamine, metaxylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl)
Cyclohexane, 1-amino-3-aminomethyl-3,
5,5-trimethylcyclohexane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, amino Aliphatic, alicyclic, and aromatic diamines such as ethylpiperazine, and adipic acid, spearic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, and 2-chloroterephthalic acid
Aliphatic, alicyclic, such as methyl terephthalic acid, 5-methyl isophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid;
An aromatic dicarboxylic acid is mentioned, and in the present invention,
The polyamide homopolymers or copolymers derived from these raw materials can each be used alone or in the form of a mixture.

In the present invention, particularly useful polyamide resins are polyamide resins having a melting point of 200 ° C. or more and excellent in heat resistance and strength. Specific examples thereof include polycaproamide (nylon 6) and polyhexamethylene. Adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyhexamethylene adipamide / polyhexamethylene Terephthalamide copolymer (nylon 6
6 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66
/ 6I), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I),
Examples include polyxylylene adipamide (nylon XD6) and mixtures or copolymers thereof. Particularly preferred are nylon 6, nylon 6
6, Nylon 610, Nylon 6/66 copolymer, Nylon 6/12 copolymer, and the like. Further, these nylon resins can be used as a mixture according to required properties such as moldability, heat resistance, toughness, and surface properties. It is practically preferable to use it.

The degree of polymerization of these nylon resins is not particularly limited, and the relative viscosity measured at 25 ° C. in a 1% concentrated sulfuric acid solution is in the range of 1.5 to 5.0, particularly 2.0 to 4.0. Those in the range of 0 are preferred.

As the polyarylene sulfide resin, any of a crosslinked type, a linear type and a branched type can be used.

The (B) inorganic filler used in the present invention refers to a fibrous or non-fibrous (for example, granular, powdery or plate-like) usually used as a resin filler or reinforcing material. Preferred examples of the fibrous inorganic filler include glass fiber, potassium titanate fiber, gypsum fiber, brass fiber, stainless steel fiber, copper fiber, steel fiber, boron whisker fiber, and carbon fiber. Preferred examples of the granular, powdery and plate-like inorganic fillers include wollastenite, sericite, kaolin, mica,
Silicates such as clay, bentonite, talc, alumina silicate, alumina, silicon oxide, magnesium oxide, zirconium oxide, metal oxides such as titanium oxide,
Carbonates such as calcium carbonate, magnesium carbonate and dolomite; sulfates such as calcium sulfate and barium sulfate;
Glass beads, glass milled fiber, boron nitride,
Examples thereof include silicon carbide and Saroyan, which may be hollow (for example, hollow glass fiber, glass microballoon, shirasu balloon, carbon balloon, and the like). According to the present invention, the inorganic filler exemplified above is uniformly dispersed in the thermoplastic resin, and as a result, an effect of improving the mechanical properties is recognized. large. The diameter of the fine particle-based inorganic filler is a fibrous material,
A plate-like material has a thickness of about 1 μm or less on average, and a particle-like or powder-like thing has a minor axis of 1 μm or less. Examples of the inorganic filler in which the technology of the present invention appears most remarkably include silicate-based inorganic fillers, and particularly, the effect on the layered silicate is great. Specific examples of the layered silicate include smectite-based clay minerals such as montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, vermiculite, various clay minerals such as halloysite, kanemite, keniyaite, zirconium phosphate, titanium phosphate, and Li-type. Examples include swellable synthetic mica such as fluorine teniolite, Na-type fluorine teniolite, Na-type tetrasilicon fluorine mica, and Li-type tetrasilicon fluorine mica, which may be natural or synthesized. Among these, smectite clay minerals such as montmorillonite and hectorite, Na-type tetrasilicon fluoromica, L
Swellable synthetic mica such as i-type fluorine teniolite is preferred. In the present invention, when a layered silicate is used as the inorganic filler (B), no special treatment is necessarily required. However, when the layered silicate has exchangeable cations between layers, the exchangeable cations are not used. A layered silicate exchanged with an organic onium ion can be preferably used. Of these, ammonium ions and phosphonium ions are preferred, and ammonium ions are particularly preferred. The ammonium ion may be any of primary ammonium, secondary ammonium, tertiary ammonium and quaternary ammonium.

The primary ammonium ion includes decyl ammonium, dodecyl ammonium, octadecyl ammonium, oleyl ammonium, benzyl ammonium and the like.

Examples of the secondary ammonium ion include methyl dodecyl ammonium, methyl octadecyl ammonium and the like.

Examples of the tertiary ammonium ion include dimethyldodecylammonium and dimethyloctadecylammonium.

Examples of the quaternary ammonium ion include benzyltrialkylammonium ions such as benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium, benzyldimethyldodecylammonium and benzyldimethyloctadecylammonium, trioctylmethylammonium, trimethyloctylammonium, trimethyldodecylammonium , Alkyltrimethylammonium ions such as trimethyloctadecylammonium, dimethyldioctylammonium, dimethyldidodecylammonium,
And dimethyldialkylammonium ions such as dimethyldioctadecylammonium.

In addition, aniline, p-phenylenediamine, α-naphthylamine, p-aminodimethylaniline, benzidine, pyridine, piperidine, 6
-Aminocaproic acid, 11-aminoundecanoic acid, 12
-Ammonium ions derived from aminododecanoic acid and the like.

Among these ammonium ions, the total number of carbon atoms in the molecule of the ammonium ion is 11 to 30.
Are particularly preferred. Specifically, trioctylmethyl ammonium, trimethyl octadecyl ammonium, benzyl dimethyl dodecylammonium, benzyl dimethyl octadecyl ammonium and the like can be used.

Further, (B) the inorganic filler is pretreated with a coupling agent having a reactive functional group (for example, an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, an epoxy compound, etc.). It is preferable to use in the sense that more excellent mechanical strength is obtained. Particularly preferred coupling agents are organic silane compounds (silane coupling agents), and specific examples thereof are γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- ( Epoxy group-containing alkoxysilane compounds such as 3,4-epoxycyclohexyl) ethyltrimethoxysilane, mercapto group-containing alkoxysilane compounds such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane, γ-ureidopropyltriethoxy Silane-containing alkoxysilane compounds such as silane, γ-ureidopropyltrimethoxysilane, γ- (2-ureidoethyl) aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopro Rutrimethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanatopropylethyldiethoxysilane, γ-isocyanatopropyltrichlorosilane, etc. Isocyanato group-containing alkoxysilane compound, γ- (2
Amino-containing alkoxysilane compounds such as -aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-hydroxypropyltrimethoxysilane, γ- Hydroxy group-containing alkoxysilane compounds such as hydroxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane hydrochloride And other alkoxysilane compounds containing a carbon-carbon unsaturated group. In particular, γ-methacryloxypropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane,
γ- (2-aminoethyl) aminopropyltrimethoxysilane and γ-aminopropyltrimethoxysilane are preferably used. These silane coupling agents are preferably subjected to surface treatment of (B) an inorganic filler in advance and then to (A) a thermoplastic resin and (C) melt-kneading in accordance with a conventional method. Without surface treatment, (A) a thermoplastic resin and (B) an inorganic filler (C)
When melt-kneading in the presence of a supercritical low molecule, a so-called integral blending method in which these coupling agents are added may be used.

The coupling agent is usually used in an amount of about 0.01 to 20% by weight based on the weight of the inorganic filler.
0.05 to 15% by weight is preferred.

The inorganic filler (B) in the present invention may be blended so that the content of the inorganic ash in the composition is 80 to 0.01% by weight, preferably 50 to 0.1% by weight. It is preferable from the point of view. The amount of the inorganic ash in the composition is a value obtained by ashing 2 g of the composition in an electric furnace at 500 ° C. for 3 hours.

In the present invention, if necessary, the addition of an olefin compound having a carboxylic anhydride group in the molecule or a polymer of these olefin compounds at the time of kneading is also effective for the purpose of improving the mechanical properties. . Specific examples of olefin compounds having a carboxylic acid anhydride group in the molecule or these olefin compounds include maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, aconitic anhydride, or a polymer of these substituted olefin compounds. And the like. In the olefin compound polymer, olefins other than the olefin compound having a carboxylic anhydride group in the molecule, such as styrene, isobutylene, methacrylic acid ester, and acrylic acid ester, are copolymerized within a range that does not impair the effects of the present invention. Although it does not matter, it is preferable that the polymer is substantially composed of a polymer of an olefin compound having a carboxylic anhydride group in the molecule. The polymerization degree of the olefin compound polymer is 2-1.
00 is preferable, 2 to 50 is more preferable, and 2 to 50 is more preferable.
20 is most preferred. Among these, maleic anhydride,
Polymaleic anhydride is most preferably used. Examples of polymaleic anhydride include, for example, J. Macromol. Sci.-Rev
Macromol. Chem., C13 (2), 235 (1975) and the like can be used.

When an olefin compound having a carboxylic anhydride group in the molecule or a polymer of the olefin compound is added, the amount of the olefin compound added is as follows:
0.05 to 10 parts by weight relative to 0 parts by weight is preferable from the viewpoint of the effect of improving impact strength and the fluidity of the composition.
It is preferably in the range of 1 to 5 parts by weight, more preferably 0.1 to 3 parts by weight.

The resin composition of the present invention can be obtained by bringing (A) a thermoplastic resin and (B) an inorganic filler into contact with (C) a supercritical fluid and kneading them. As a mode of kneading, melt kneading is preferable.

The supercritical fluid referred to here is a temperature higher than the critical temperature,
A third fluid that has intermediate properties between a gas and a liquid at a pressure equal to or higher than the critical pressure but is neither of them, and has a larger diffusion coefficient than a liquid. Substances that can relatively easily form a supercritical fluid include carbon dioxide, ammonia, methane, and the like.For use in the present invention, the temperature is usually higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature. What can become a supercritical fluid in the region is preferable. As the supercritical fluid used in the present invention, carbon dioxide is most preferable in terms of effect.

The amount of the supercritical fluid used in the present invention is preferably from 0.01 to 30% by weight, particularly preferably from 0.1 to 20% by weight, based on the composition to be brought into contact.

In the present invention, there is no particular limitation on an apparatus for bringing the (A) thermoplastic resin and the (B) inorganic filler into contact with the (C) supercritical fluid and kneading the same. As long as the device can be pressurized at a temperature higher than the melt processing temperature and higher than the critical pressure, any of a batch system and a continuous system can be preferably used. As an example, a single-screw or twin-screw extruder used for melting and kneading a thermoplastic resin, which is provided with an injection port for a pressurized fluid, can be preferably used. More specifically, on the nozzle side than the plasticizing zone of the extruder, an inlet for introducing a supercritical fluid was provided at a position where the thermoplastic resin was completely melted, and provided at a position where kneading was completely completed. It is effective to provide a device for discharging low-molecular molecules in a supercritical state as a gas by reducing the pressure in the vent port.

Further, the resin composition of the present invention contains various commonly used additives, a crystal nucleating agent, an anti-coloring agent, an antioxidant such as hindered phenol and hindered amine, and an ethylene bis-bisulfate as long as the object of the present invention is not impaired. Additives such as release agents such as stearylamide and higher fatty acid esters, plasticizers, heat stabilizers, lubricants, UV inhibitors, coloring agents and flame retardants can be added.

The thermoplastic resin composition of the present invention can be formed by extrusion molding.
A molded product can be easily formed by a normal processing method such as injection molding.

[0035]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. All compounding ratios are parts by weight.

Example 1 Using a 30 mm twin-screw extruder having a gas addition port at a portion of a kneading zone set at 250 ° C. from a resin supply port and a vent port at a portion of a kneading zone from a discharge port, concentrated sulfuric acid was used.
85 parts by weight of nylon 6 having a relative viscosity of 2.74 measured at 25 ° C. at a concentration of 1% and 15 parts by weight of kaolin treated with a silane coupling agent were continuously supplied, and further provided in an extruder barrel. A liquefied carbon dioxide cylinder was connected to the gas addition port via a high-pressure pump, and about 3% by weight of carbon dioxide with respect to the composition was introduced while maintaining the pressure at or above the critical pressure. The mixture was kneaded with care to obtain pellets. After the obtained composition pellets were dried, the cylinder temperature was 250 ° C. and the mold temperature was 80.
Injection molding was performed at 0 ° C. to form an ASTM No. 1 test piece having a thickness of １ ／ ″ and a rod-shaped test piece having a thickness of ”″ × 5 ″ × １ ／ ″.

ASTM D6 using ASTM No. 1 test piece
Tensile test according to Method 38 and AST using rod-shaped test pieces
A bending test was performed according to the MD790 method, and the results shown in Table 1 were obtained.

Reference Example 1 Na-type montmorillonite (Kunimine Industries: Knipia F,
100 g of a cation exchange capacity (120 meq / 100 g) was stirred and dispersed in 10 liters of warm water, and 2 L of warm water in which 48 g (equivalent to the cation exchange capacity) of trioctylmethylammonium chloride was dissolved, and stirred for 1 hour. . The resulting precipitate was separated by filtration and washed with warm water. This washing and filtration were repeated three times, and the obtained solid was vacuum-dried at 80 ° C. to obtain a dried organic layered silicate. When the amount of inorganic ash in the obtained organically modified layered silicate was measured, the proportion of inorganic ash was 67% by weight. The inorganic ash content of the layered silicate was determined by adding 0.1 g of the layered silicate to an electric furnace at 500 ° C.
It is a value obtained by time ashing.

Example 2 96.2 parts by weight of nylon 6 having a relative viscosity of 2.74 and 3.8 parts by weight of the organically modified layered silicate obtained in Reference Example 1 were blended and preblended by a tumbler mixer. Using the twin-screw extruder used in Example 1 in which the cylinder temperature was set to 250 ° C., the supercritical carbon dioxide was melt-kneaded while being introduced into the composition at a ratio of about 2% by weight, and the resin composition was Obtained. The resulting composition was pelletized and then heated at 80 ° C. for 10 hours.
Time vacuum drying, cylinder temperature 250 ° C, mold temperature 80
Injection molding was performed at ℃ to obtain a test piece. About 2 g of test piece
Ashing was performed in an electric furnace at 00 ° C. for 3 hours to determine the amount of inorganic ash. As a result, the proportion of inorganic ash was 2.5% by weight. Table 1 shows the evaluation results of the mechanical properties.

Example 3 The Na-type montmorillonite used in Reference Example 1 was used without any particular treatment. Nylon 6 used in Example 1
97.5 parts by weight and 2.5 parts by weight of Na-type montmorillonite were pre-blended with a tumbler mixer, and then the supercritical carbon dioxide was added using the twin-screw extruder used in Example 1 in which the cylinder temperature was set to 250 ° C. The composition was melt-kneaded while being introduced at a ratio of about 2% by weight to obtain a resin composition. The resulting composition was pelletized and then heated at 80 ° C. for 10 hours.
Time vacuum drying, cylinder temperature 250 ° C, mold temperature 80
Injection molding was performed at ℃ to obtain a test piece.

Example 4 96.2 parts by weight of polybutylene terephthalate having an intrinsic viscosity of 1.2 measured at 25 ° C. at a concentration of 0.5% in an o-chlorophenol solution, 96.2 parts by weight of the organically modified layer obtained in Reference Example 1 After mixing 3.8 parts by weight of silicate and pre-blending with a tumbler mixer, supercritical carbon dioxide was added to the composition using the twin-screw extruder used in Example 1 in which the cylinder temperature was set to 250 ° C. The mixture was melt-kneaded while being introduced at a ratio of about 2% by weight to obtain a resin composition. After the resulting composition was pelletized, it was dried with hot air at 130 ° C. for 4 hours.
Injection molding was performed at 50 ° C. and a mold temperature of 80 ° C. to obtain a test piece. About 2 g of the test piece was ashed in an electric furnace at 500 ° C. for 3 hours, and the amount of inorganic ash was determined to be 2.5 wt%.
Table 1 shows the evaluation results of the mechanical properties.

Comparative Example 1 The same composition as in Example 1 was prepared in the absence of (C) carbon dioxide in a supercritical state. Table 1 shows the measurement results of the mechanical properties.

Comparative Example 2 A composition similar to that of Example 2 was prepared in the absence of (C) carbon dioxide in a supercritical state. Table 1 shows the measurement results of the mechanical properties.

Comparative Example 3 A composition similar to that of Example 3 was prepared in the absence of (C) carbon dioxide in a supercritical state. Table 1 shows the measurement results of the mechanical properties.

Comparative Example 4 A composition similar to that of Example 4 was prepared in the absence of (C) carbon dioxide in a supercritical state. Table 1 shows the measurement results of the mechanical properties.

[0046]

[Table 1]

[0047]

According to the present invention, it is possible to uniformly blend an inorganic filler, particularly a fine inorganic filler which is liable to cause secondary agglomeration, into a thermoplastic resin, and to obtain a resin composition exhibiting excellent mechanical properties. Can now be obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08L 67/00 C08L 67/00 77/00 77/00 81/02 81/02 F term (reference) 4F070 AA12 AA18 AA32 AA42 AA47 AA50 AA52 AA54 AA58 AC01 AC04 AC06 AC07 AC16 AC20 AC22 AC23 AC28 AC29 AC42 AD02 AD03 AD10 AE01 FA03 FB10 FC05 4J002 BB001 BC021 BG001 BN151 CB001 CF001 CG001 CH071 CL001 CL011 CL031 CL051 DJ01 016 DJ016 016001 DL006 FA046 FA096 FD016

Claims (8)

[Claims] 1. A resin composition obtained by bringing (A) a thermoplastic resin and (B) an inorganic filler into contact with (C) a supercritical fluid and kneading them. 2. The composition according to claim 1, wherein the content of the inorganic filler (B) is 80% in the composition.
The fat composition according to claim 1, wherein the amount is from 0.01 to 0.01% by weight. 3. The resin composition according to claim 1, wherein (A) the thermoplastic resin is at least one resin selected from the group consisting of a polyamide resin, a saturated polyester resin, an ABS resin, and a polyphenylene sulfide resin. object. 4. The resin composition according to claim 1, wherein (B) the inorganic filler is a silicate-based inorganic filler. 5. The resin composition according to claim 1, wherein (C) the supercritical fluid is supercritical carbon dioxide. 6. The resin according to claim 1, wherein (A) a thermoplastic resin and (B) an inorganic filler are brought into contact with (C) a supercritical fluid in a batch type mixing tank and kneaded. A method for producing a resin composition, comprising producing a composition. 7. The method according to claim 1, wherein (A) a thermoplastic resin and (B) an inorganic filler are kneaded by using a continuous mixer and (C) by bringing them into contact with a supercritical fluid. A method for producing a resin composition, comprising producing the resin composition according to any one of the preceding claims. 8. A method in which (A) a thermoplastic resin and (B) an inorganic filler are brought into contact with (C) a supercritical fluid and kneaded, and when the kneading is completed, the pressure in the system is reduced.
(C) A method for producing a resin composition, comprising producing the resin composition according to any one of claims 5 and 6 by taking out a supercritical fluid as a gas outside the system.