JP2000053847A - Polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellent in a balance between rigidity and toughness and capable of weight reduction by melt-kneading a thermoplastic polyester having a specified terminal carboxy content and a layered silicate derived by exchanging the exchangeable cations present among layers for organic onium ions. SOLUTION: The thermoplastic polyester has a terminal carboxy content of 10-80 eq/t and is particularly desirably polybutylene terephthalate, polyethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, or the like. The organic onium ions are desirably ammonium ions or phosphonium ions between which the former ions are particularly desirable. Among the ammonium ions, phenyl-containing ammonium ions are particularly desirable. The content of the layered silicate is usually 0.1-40 wt.% (in terms of the inorganic ash content in the composition).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition comprising a thermoplastic polyester and a layered silicate having improved mechanical properties.

[0002]

2. Description of the Related Art Conventionally, in order to improve the mechanical properties of a thermoplastic polyester resin, it has been practiced to incorporate a glass fiber or an inorganic filler into the resin. However, simply melting and kneading these inorganic fillers causes problems such as poor dispersion of the inorganic filler in the resin and poor interfacial adhesion, low impact resistance, and poor surface appearance. Therefore, in order to increase the affinity or bonding strength between the thermoplastic resin and the inorganic filler, there is a method of improving the dispersion of the filler in the resin by applying a coupling treatment such as an organic silane to the surface of the inorganic filler. However, it is only enough to improve the conformability between the resin and the inorganic filler, and has not been sufficiently improved. In addition, in order to obtain sufficient strength, it is necessary to increase the filling amount of a normal filler, and there is a problem that the obtained polyester resin composition has a high specific gravity.

[0003] On the other hand, clay minerals, which are a kind of inorganic layered compounds, have been tried for a long time as fillers. However, in ordinary mixing and kneading, secondary aggregation occurs, and uniform mixing in the polyester resin occurs. Dispersion was difficult. Therefore, Japanese Patent Application Laid-Open No. 3-62846 discloses an attempt to obtain a uniform dispersion by using an interlayer compound having a layered silicate as a host and an organic onium ion as a guest and a compatibilizer. Although an improvement in the modulus of elasticity was observed, the addition of a compatibilizer was not satisfactory in terms of a reduction in impact strength. Further, Japanese Patent Application Laid-Open
JP-A-166036 discloses that a layered silicate is used as a host,
Although a polyester resin composition comprising an intercalation compound having a specific quaternary ammonium salt as a guest is disclosed, improvement in rigidity is recognized but is not satisfactory in terms of toughness.

[0004]

Accordingly, the present invention is to solve the above-mentioned problems, that is, to provide a polyester resin composition which is excellent in balance between rigidity and toughness and which can be reduced in weight due to a small amount of an inorganic substance added. The challenge is to obtain.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a thermoplastic polyester having a specific amount of terminal groups and an organic onium ion are inserted between the layers. The present inventors have found that the problem can be solved by using a silicate, and have reached the present invention.

That is, the present invention provides a polyester resin composition obtained by melt-kneading (a) a thermoplastic polyester and (b) a layered silicate in which exchangeable cations present between layers have been exchanged with organic onium ions. (A) the thermoplastic polyester has a carboxyl end group content of 10 to 80 e
q / t, which is a polyester resin composition.

[0007]

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

The thermoplastic polyester resin (a) includes a thermoplastic polyester resin having an aromatic ring in a chain unit of a polymer, and is 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 mainly containing an ester-forming derivative) and / or a hydroxycarboxylic acid. These may be liquid crystalline or non-liquid crystalline.

Specific examples of preferred polyesters in the present invention include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate,
Polyalkylene terephthalate such as polycyclohexane dimethylene terephthalate and polyhexylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, polybutylene-2,6-naphthalenedicarboxylate, polyethylene-1,2-bis (phenoxy) ethane- In addition to 4,4′-dicarboxylate, polyethylene isophthalate / terephthalate, polybutylene isophthalate / terephthalate, polybutylene terephthalate / decane dicarboxylate, polyethylene-4,4′-dicarboxylate / terephthalate,
Non-liquid crystalline polyesters such as poly (ethylene terephthalate / cyclohexane dimethylene terephthalate).

The liquid crystalline polyester forms an anisotropic molten phase composed of structural units selected from aromatic oxycarbonyl units, aromatic dioxy units, aromatic dicarbonyl units, ethylenedioxy units and the like. Polyester can be mentioned.

The aromatic oxycarbonyl unit includes, for example, p-hydroxybenzoic acid, 6-hydroxy-2-
Structural units generated from naphthoic acid, aromatic dioxy units include, for example, 4,4′-dihydroxybiphenyl, hydroquinone, structural units generated from t-butylhydroquinone, and aromatic dicarbonyl units include, for example, terephthalic acid, Examples of the structural unit generated from isophthalic acid and 2,6-naphthalenedicarboxylic acid and the aromatic iminooxy unit include a structural unit generated from 4-aminophenol. Specific examples include liquid crystalline polyesters such as p-oxybenzoic acid / polyethylene terephthalate and p-oxybenzoic acid / 6-oxy-2-naphthoic acid.

Particularly preferred are polybutylene terephthalate, polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate. These polyester resins can be used to obtain necessary properties such as moldability, heat resistance, toughness and surface properties. Accordingly, it is practically preferable to use it as a mixture.

The degree of polymerization of these thermoplastic polyesters is not limited, but polybutylene terephthalate is 0.5%.
% O-chlorophenol solution at 25 ° C. has an intrinsic viscosity in the range of 0.80 to 1.9, especially 1.0 to 1.
In the case of polyethylene terephthalate, the intrinsic viscosity measured under the same conditions as above is preferably in the range of 0.36 to 1.60, particularly preferably in the range of 0.52 to 1.35.

The amount of carboxyl terminal groups of these thermoplastic polyesters is preferably in the range of 10 to 80 eq / t (terminal group amount per ton of polymer), more preferably in the range of 20 to 50 eq / t. Things.
The amount of the carboxyl terminal group is quantitatively determined by a known method. For example, the amount is determined by potentiometric titration of an o-cresol solution with an alkaline solution. If the amount of the carboxyl terminal group is too small, the dispersibility of the layered silicate becomes insufficient, and if it is too large, the drop in impact strength becomes remarkable, and neither is preferable.

In the present invention, the term “(b) a layered silicate in which exchangeable cations present between layers are exchanged with organic onium ions” refers to (b-1) the exchange of layered silicates having exchangeable cations between layers. This is an inclusion compound in which a cation of the nature is replaced by (b-2) an organic onium ion.

(B-1) The layered silicate having exchangeable cations between layers is 0.05 to 0.5 μm in width and 6 to 1 in thickness.
It has a structure in which 5-angstrom plate-like materials are stacked, and has exchangeable cations between layers of the plate-like materials. The cation exchange capacity is 0.2 to 3 meq / g, and preferably the cation exchange capacity is 0.8 to 1.5 m
eq / g.

Specific examples of the layered silicate include smectite clay minerals such as montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, and vermiculite, various clay minerals such as halloysite, kanemite, keniyaite, zirconium phosphate, and titanium phosphate. Swelling synthetic mica such as Li-type fluorine teniolite, Na-type fluorine teniolite, Na-type tetrasilicon fluoromica, Li-type tetrasilicon fluoromica, and the like, whether natural or synthesized. good. Among these, smectite clay minerals such as montmorillonite and hectorite, and swellable synthetic mica such as Na-type tetrasilicon fluorine mica and Li-type fluorine teniolite are preferred.

(B-2) Examples of the organic onium ion include an ammonium ion, a phosphonium ion, and a sulfonium ion. Among these, ammonium ions and phosphonium ions are preferable, and ammonium ions are particularly preferably used. 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.

The secondary ammonium ion includes 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 and 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, an ammonium ion having a phenyl group is particularly preferred. Specific examples include benzylammonium, benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium, benzyldimethyldodecylammonium, benzyldimethyloctadecylammonium and the like, among which benzyldimethyldodecylammonium and benzyldimethyloctadecylammonium are preferable.

In the present invention, (b) a layered silicate in which exchangeable cations present between layers are exchanged with organic onium ions is (b-1) a layered silicate having exchangeable cations between layers. 2) It can be produced by reacting an organic onium ion by a known method. Specific examples include a method based on an ion exchange reaction in a polar solvent such as water, methanol and ethanol, and a method based on directly reacting a liquid or molten ammonium salt with a layered silicate.

In the present invention, the amount of the organic onium ion with respect to the layered silicate is determined based on the dispersibility of the layered silicate, the thermal stability during melting, the gas during molding, and the suppression of generation of odor. Typically 0.4 for cation exchange capacity
The range is from 2.0 to 2.0 equivalents, but preferably from 0.8 to 1.2 equivalents.

Further, it is preferable to use these layered silicates by pre-treating them with a coupling agent having a reactive functional group in addition to the above-mentioned organic onium salt in order to obtain more excellent mechanical strength. Examples of such a coupling agent include an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, and an epoxy compound.

Particularly preferred are organic silane compounds, examples of which include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxy). Epoxy group-containing alkoxysilane compounds such as cyclohexyl) ethyltrimethoxysilane, mercapto group-containing alkoxysilane compounds such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane,
ureido group-containing alkoxysilane compounds such as γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ- (2-ureidoethyl) aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ- Isocyanatopropyltrimethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanatopropylethyldiethoxysilane, γ-isocyanatopropyl Isocyanato group-containing alkoxysilane compounds such as trichlorosilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ Amino group-containing alkoxysilane compounds such as aminopropyltrimethoxysilane, .gamma.-hydroxypropyl trimethoxysilane, .gamma.
Hydroxyl-containing alkoxysilane compounds such as hydroxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, N
And carbon-carbon unsaturated group-containing alkoxysilane compounds such as -β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane / hydrochloride.
In particular, a carbon-carbon unsaturated group-containing alkoxysilane compound is preferably used. The treatment of the layered silicate with these silane coupling agents can be carried out by adsorbing the silane coupling agent to the layered silicate in a polar solvent such as water, methanol, or ethanol, or a mixed solvent thereof, or by using a Henschel mixer or the like. A method in which a layered silicate is added to a high-speed stirring mixer, and the mixture is dropped and adsorbed in the form of an aqueous solution containing a silane coupling agent or an organic solvent while stirring, and the silane coupling agent is directly added to the layered silicate. Then, any method of mixing and adsorbing in a mortar or the like may be used. When the layered silicate is treated with a silane coupling agent, it is preferable to simultaneously mix water, acidic water, alkaline water and the like in order to promote the hydrolysis of the alkoxy group of the silane coupling agent. Further, in order to enhance the reaction efficiency of the silane coupling agent, water such as methanol or ethanol and an organic solvent that dissolves both the silane coupling agent may be mixed in addition to water. The reaction can be further promoted by heat-treating the layered silicate treated with such a silane coupling agent. When the layered silicate and the thermoplastic polyester are melt-kneaded without using a layered silicate with a coupling agent in advance, a so-called integral blending method of adding these coupling agents may be used.

In the present invention, the content of the layered silicate (b) in which the exchangeable cation existing between the layers is exchanged with the organic onium ion is 0.1% as the inorganic ash content in the composition of the present invention.
The range is 1 to 40% by weight, preferably 1 to 30% by weight, particularly preferably 3 to 15% by weight. If the ash content is too small, the effect of improving the physical properties is small, and if the ash content is too large, the toughness may decrease. The inorganic ash content is a value obtained by incinulating 2 g of the thermoplastic resin composition in an electric furnace at 500 ° C. for 3 hours.

The (c) organic compound having at least one functional group reactive with the thermoplastic polyester used in the present invention, if necessary, chemically reacts with the terminal group of the thermoplastic polyester. An organic compound having one or more functional groups in a molecule that can be used. The functional group is not particularly limited as long as it is reactive with a carboxyl group or a hydroxyl group which is a terminal group of the thermoplastic polyester. Preferred examples thereof include a carboxylic acid anhydride group, an epoxy group, an isocyanate group, and a carbodiimide group. And an oxazoline group. Compounds having one or more of these functional groups in the molecule include olefin compounds having a carboxylic anhydride group in the molecule, or polymers of these olefin compounds, monoepoxy compounds, diepoxy compounds, polyepoxy compounds, and isocyanate compounds. , Diisocyanate compounds, carbodiimide compounds, polycarbodiimide compounds, oxazoline compounds, bisoxazoline compounds, and the like.

Among these compounds, preferred compounds include olefin compounds having a carboxylic anhydride group in the molecule or polymers of these olefin compounds. Specific examples thereof include maleic anhydride, itaconic anhydride,
Examples include glutaconic anhydride, citraconic anhydride, aconitic anhydride, and polymers of these substituted olefin compounds. 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 preferably from 2 to 100,
0 is more preferable, and 2 to 20 is most preferable. Among them, maleic anhydride and polymaleic anhydride are most preferably used. As polymaleic anhydride,
For example, J. Macromol. Sci.-Revs. Macromol. Chem., C13
(2), 235 (1975) and the like can be used.

The olefin compound having a carboxylic anhydride group in the molecule or a polymer of these olefin compounds used here may have an anhydride structure substantially when melt-kneaded with a thermoplastic polyester. The olefin compound or the polymer of the olefin compound is hydrolyzed and subjected to melt-kneading in the form of a carboxylic acid or an aqueous solution thereof, and subjected to a dehydration reaction by heating during the melt-kneading,
It may be melt-kneaded with the thermoplastic polyester substantially in the form of an acid anhydride.

Another preferred compound as the component (c) is an epoxy compound. Specific examples thereof include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether,
Monoepoxy compounds such as glycidyl benzoate and glycidyl methacrylate, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol A type epoxy resin, Diglycidyl compounds such as glycidyl phthalate, diglycidyl cyclohexanedicarboxylate, glycidyl ether oxybenzoate, glycerol polyglycidyl ether, trimethylolpropane diglycidyl ether, sorbitol diglycidyl ether, glycidyl methacrylate / ethylene copolymer, etc. And the like.

Of these, polyethylene glycol diglycidyl ether, bisphenol A type epoxy resin, glycidyl oxybenzoate and the like are preferred. These may be used alone or in combination of two or more.

In the present invention, when (c) an organic compound having at least one functional group reactive with a thermoplastic polyester in a molecule is added, the amount of the organic compound to be added is 0 to 100 parts by weight of (a) the thermoplastic polyester. 0.05 to 10 parts by weight is preferable from the viewpoint of the effect of improving the impact strength and the fluidity of the composition, more preferably 0.1 to 5 parts by weight, and further preferably 0.1 to 3 parts by weight. is there.

In the present invention, there is no particular limitation on the method of melt-kneading the layered silicate in which the exchangeable cations present between the (a) thermoplastic polyester (b) layers have been exchanged with organic onium ions. It suffices if mechanical shearing can be performed in a molten state. The processing method may be either a batch method or a continuous method, but a continuous method capable of continuous production is preferable from the viewpoint of working efficiency. Further, if necessary, even when (c) an organic compound having at least one functional group reactive with the thermoplastic polyester is blended in the molecule, the method of adding the organic compound is not limited, and (a) the thermoplastic polyester and ( b) a method of pre-blending the layered silicate before melt-kneading, a method of adding (a) and (b) during melt-kneading, and the like.
The specific kneading apparatus is not limited, but an extruder, particularly a twin-screw extruder, is preferable in terms of productivity. In addition, for the purpose of removing water and low molecular weight volatile components generated during melt kneading,
It is also preferred to provide a vent port.

Further, the polyester resin composition of the present invention may contain various commonly used additives within the range not impairing the object of the present invention, for example, glass fiber, carbon fiber, acicular inorganic filler such as acicular wollastenite, and glass. Flaky, talc, kaolin, mica and other plate-like inorganic fillers, impact modifiers such as various elastomers, crystal nucleating agents, coloring inhibitors, antioxidants such as hindered phenols and hindered amines, ethylenebisstearylamide and high-grade Additives such as release agents such as fatty acid esters, plasticizers, heat stabilizers, lubricants, UV inhibitors, coloring agents, and flame retardants can be added.

The polyester resin composition of the present invention can be easily formed into a molded product by ordinary processing methods such as extrusion molding and injection molding. The obtained molded product has a small amount of filler,
Because of its high flexural modulus and excellent impact strength, it is suitable for various engineering parts and structural materials.

[0039]

The present invention will be described in more detail with reference to the following examples.

Evaluation Items and Measurement Methods Tensile test: Evaluated according to ASTM D638 using an ASTM No. 1 dumbbell test piece having a thickness of ８ ″.

Bending test: A bar-shaped test piece of １ ／ ″ × 5 ″ × １ ／ ″ was evaluated according to ASTM D790.

Impact test: An Izod impact test piece having a thickness of 1/8 "was evaluated according to ASTM D256.

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 51 g of benzyldimethyloctadecyl ammonium chloride (equivalent to the cation exchange capacity) was added.
Stirred for hours. 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.

Reference Example 2 100 g of Na-type synthetic mica (COPE CHEMICAL: ME-100, cation exchange capacity: 80 m equivalent / 100 g) was added to hot water 1
The mixture was stirred and dispersed in 0 L, and 2 L of warm water in which 34 g (equivalent to the cation exchange capacity) of benzyldimethyloctadecyl ammonium chloride was added, and the mixture was stirred for 1 hour. Thereafter, it was recovered, washed and dried in the same manner as in Reference Example 1 to obtain a dried organically modified layered silicate.

Reference Example 3 An organically modified layered silicate was produced in the same manner as in Reference Example 1, using 100 g of montmorillonite and 30.2 g of 12-aminododecanoic acid hydrochloride (equivalent to the cation exchange capacity) as in Reference Example 1. did.

Reference Example 4 An organically modified layered silicate was produced in the same manner as in Reference Example 1, except that 100 g of montmorillonite and 70 g of dimethyldioctadecyl ammonium chloride (equivalent to the cation exchange capacity) were used as raw materials. Example 1 In an o-chlorophenol solution, the concentration was 0.5%, the intrinsic viscosity measured at 25 ° C. was 1.2, and the amount of carboxyl end groups determined by potentiometric titration with an o-cresol solution was 43 eq / t.
Polybutylene terephthalate (PBT-1) 95.7
Parts by weight and 4.3 parts by weight of the layered silicate obtained in Reference Example 1 were blended and pre-blended by a tumbler mixer.
The mixture was melt-kneaded with a TEX-30 twin-screw extruder (Nippon Steel Works) set at a cylinder temperature of 250 ° C. to obtain a resin composition. The resulting composition was pelletized and then dried at 110 ° C. for 8 hours.
Time hot air drying, cylinder temperature 250 ° C, mold temperature 80
Injection molding was performed at ℃ to obtain a test piece. 2 g of test piece is 50
Ashing was performed in an electric furnace at 0 ° C. for 3 hours to determine the amount of inorganic ash, which was 3.0% by weight. Table 1 shows the evaluation results of the mechanical properties.

Example 2 The same polybutylene terephthalate (PBT-1) as used in Example 1 and the layered silicate obtained in Reference Example 2 were blended according to the formulation shown in Table 1, and the same as in Example 1. Was melt-kneaded to obtain a composition, and after injection molding, physical properties were evaluated.

Example 3 The same polybutylene terephthalate (PBT-1) as used in Example 1, the layered silicate obtained in Reference Example 1, and maleic anhydride were blended according to the formulation shown in Table 1. After blending with a tumbler mixer, the mixture was melt-kneaded in the same manner as in Example 1, and after injection molding, physical properties were evaluated.

Example 4 The same polybutylene terephthalate (PBT-1) as used in Example 1, the layered silicate obtained in Reference Example 1, and polymaleic anhydride (average degree of polymerization 8) are shown in Table 1. After blending with the indicated formulation and blending with a tumbler mixer, they were melt-kneaded in the same manner as in Example 1, and after injection molding, physical properties were evaluated.

Examples 5 and 6 Using the same polybutylene terephthalate (PBT-1) as used in Example 1 and the organically modified layered silicate produced in Reference Example 3 or 4, the formulation was as shown in Table 1. Example 1
After the composition was obtained by melt-kneading in the same manner as in the above, molding evaluation was performed.

Comparative Example 1 In an o-chlorophenol solution, the concentration was 0.5%, the intrinsic viscosity measured at 25 ° C. was 1.2, and the amount of carboxyl terminal groups determined by potentiometric titration with an o-cresol solution was 9 eq / t. 95.7 parts by weight of polybutylene terephthalate (PBT-2) and 4.3 parts by weight of the layered silicate obtained in Reference Example 1 were blended, and a composition was obtained in the same manner as in Example 1, and the physical properties after molding were measured. evaluated. Further, the amount of inorganic ash in the composition was measured in the same manner as in Example 1, and was found to be 3.0% by weight.

Comparative Example 2 In an o-chlorophenol solution, the concentration was 0.5%, the intrinsic viscosity measured at 25 ° C. was 1.0, and the amount of carboxyl terminal groups determined by potentiometric titration with an o-cresol solution was 90 eq / t.
Of polybutylene terephthalate (PBT-3), and the layered silicate obtained in Reference Example 1 by the formulation shown in Table 2,
A composition was obtained in the same manner as in Example 1, and the physical properties after molding were evaluated.

Comparative Example 3 The same polybutylene terephthalate as used in Example 1 and the montmorillonite used as a raw material in Reference Example 1 were melt-kneaded in the same formulation as in Example 1 with the blending recipe shown in Table 2. After obtaining the composition, molding evaluation was performed.

Comparative Example 4 The same polybutylene terephthalate as that used in Example 1 was injection-molded in the same manner as in Example 1, and the physical properties were evaluated.

[0055]

[Table 1]

[0056]

According to the present invention, even if the amount of inorganic ash is small, a resin composition having excellent rigidity such as flexural modulus and strength and excellent balance with impact strength can be obtained. Suitable for molded products such as electronic parts, building materials, furniture, and daily necessities.

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Claims (7)

[Claims] 1. A thermoplastic polyester and (b)
A polyester resin composition obtained by melt-kneading a layered silicate in which exchangeable cations existing between layers have been exchanged with organic onium ions, wherein the (a) thermoplastic polyester has a carboxyl terminal group content of 10 to 80 eq / t. A polyester resin composition characterized by the following. (B) The composition contains a layered silicate in which exchangeable cations present between the layers have been exchanged with organic onium ions in an amount of 0.1 to 40% by weight in terms of inorganic ash in the composition. The polyester resin composition according to claim 1. 3. The polyester resin composition according to claim 1, wherein (a) the thermoplastic polyester is a polyalkylene terephthalate. 4. The method according to claim 1, wherein (b) the layered silicate is a layered silicate in which exchangeable cations existing between layers have been exchanged with an organic ammonium ion having a phenyl group. Polyester resin composition. Further, 0.05 to 10 parts by weight of (c) an organic compound having at least one functional group reactive with the thermoplastic polyester in the molecule is added to (a) 100 parts by weight of the thermoplastic polyester. The polyester resin composition according to any one of claims 1 to 4, which is melt-kneaded. 6. The functional group of the organic compound having at least one functional group reactive with the thermoplastic polyester in the molecule is a carboxylic acid anhydride group and / or an epoxy group. The polyester resin composition according to claim 5. (C) the organic compound having at least one functional group reactive with the thermoplastic polyester in the molecule is an olefin compound having a carboxylic anhydride group in the molecule or a polymer of the olefin compound; The polyester resin composition according to claim 5 or 6, wherein