JP3109144B2 - Foam molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamed molded article having excellent mechanical properties and excellent heat resistance. More specifically, the present invention relates to a foamed molded article having stable mechanical properties, a small decrease in strength due to foaming, a greatly improved anisotropy of a liquid crystal polymer, and usable as a lightweight engineering material.

[0002]

2. Description of the Related Art Hitherto, polystyrene and polyvinyl chloride foams have been widely known as thermoplastic polymer foam molded articles. On the other hand, in recent years, the demand for higher performance of plastics has been increasing more and more, and various polymers having various new performances have been developed. Among them, optically anisotropic liquid crystal polymers have attracted attention because of their excellent mechanical properties. (JP-A-51-8395, JP-A-49-7239).
No. 3), and a technique relating to a liquid crystal polymer foam such as a liquid crystal polyester having a naphthalene skeleton and a liquid crystal polyester obtained by copolymerizing polyethylene terephthalate and p-acetoxybenzoic acid is also known (Japanese Patent Application Laid-Open No. 58-1983).
-19336, JP-A-58-93731).

[0003]

The foamed molded article of polystyrene or polyvinyl chloride, which is conventionally known as a foamed thermoplastic polymer, gives favorable results for the purpose of weight reduction, but the mechanical properties due to foaming. Above all, a remarkable decrease in tensile strength, impact strength and elastic modulus is caused. Japanese Patent Application Laid-Open Nos. 58-19336 and 58-93731 describe foam moldings of the liquid crystal polymer.
According to the technique disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, there is a problem that a foam molded article having improved isotropic properties can be obtained, but a foam molded article having excellent heat resistance cannot always be obtained.

[0004] When foaming a known liquid crystal polymer, the size of the foam structure tends to be non-uniform as compared with an isotropic thermoplastic polymer, so that the mechanical properties are different between the molded articles and between one molded article and the other. It was found that there was a tendency to vary in the molded body.

Accordingly, the present invention has been made to solve the above-mentioned problems, and to obtain a foam molded article which is excellent in a balance between mechanical properties and heat resistance and has a uniform foam structure and mechanical properties and which can be used as a lightweight engineering material. Make it an issue.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have formed a foamed polyester resin having a specific structure or a specific composition containing the copolymer polyester as a component. The present inventors have found that a foam molded article is suitable for solving the above-mentioned problems, and have reached the present invention.

That is, the present invention (1) comprises the following structural units (I) to (IV), wherein the structural units (I) and (II)
Is the sum of the structural units (I), (II) and (III)
80 to 93 mol% with respect to the structural unit (III) is structural units
20 to the sum of positions (I), (II) and (III)
7 mol%, and the molar ratio of the structural units (I) and (II)
[(I) / (II)] is 78/22 to 93/7, the melting point (Tm, ° C) satisfies the expression (1), and the logarithmic viscosity is 1.0 to 1.0.
A foam molded article obtained by foam molding a copolymer polyester (A) having a melt anisotropy of 3.0 dl / g;

[0008]

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[0009] -10 <Tm + 5.89x-385.5 < 10 ... (1) ( provided that (1) the structural unit of x is the structural unit (III) in the formula
The ratio (mol%) to the total of (I), (II) and (III ) is shown. (2) Contains at least one component selected from (B) a filler, (C) an organic polymer flame retardant, and (D) a thermoplastic polymer, based on the copolymerized polyester (A) described in (1). It is a foam molded article obtained by subjecting the copolymerized polyester composition to foam molding.

[0010] In the present invention, it is important to use a specific limited copolymerized polyester or a composition thereof to form a foamed molded article, thereby exerting the effects of the present invention.

The structural unit (I) is a structural unit of a polyester formed from p-hydroxybenzoic acid, and the structural unit (II) is a structural unit formed from 4,4'-dihydroxybiphenyl, ) Indicates a structural unit generated from ethylene glycol, and structural unit (IV) indicates a structural unit generated from terephthalic acid.

The structural unit (III) is a structural unit (I),
It is 20 to 7 mol%, preferably 17 to 8 mol%, more preferably 14 to 8 mol%, based on the total of (II) and (III) . Structural units (I) and (II)
Is the sum of the structural units (I), (II) and (III)
If it is more than 93 mol%, the melt fluidity decreases and solidifies during polymerization, and if it is less than 80 mol%, the heat resistance becomes poor and any case is not preferable. Also structural units
The molar ratio [(I) / (II)] between (I) and (II) is 78/22
９３93/7, preferably 85/15 to 92/8, and more preferably 91/9 to 92/8. 78
If the ratio is less than / 22 or greater than 93/7, the object of the present invention cannot be achieved because the heat resistance is poor, the flowability is poor, and the uniformity of the cell structure is impaired.

The structural unit (IV) is substantially a structural unit
It is equimolar to the sum of (II) and (III) .

In the method for producing the copolymerized polyester of the present invention, the method of the melt polymerization method is preferably carried out until substantially all of the solid polydispersed state becomes a solid phase, because of the random nature of the polymer. Is more preferable than the method in which Particularly preferred production methods include, for example, p-hydroxybenzoic acid,
A method of reacting 4,4'-dihydroxybiphenyl with acetic anhydride or terephthalic acid with a polyethylene terephthalate polymer, oligomer or bis (β-hydroxyethyl) terephthalate and producing it in a molten state by deacetic acid polymerization is used.

Although this polycondensation reaction proceeds without a catalyst,
In some cases, it is preferable to add a metal compound such as stannous acetate, tetrabutyl titanate, sodium acetate and potassium acetate, antimony trioxide, and metallic magnesium.

The melting point (Tm, ° C.) of the copolymerized polyester of the present invention must satisfy the following formula (1).

[0017] -10 <Tm + 5.89x-385.5 < 10 ... (1) structural unit of here in (1) x in the formula of the structural unit (III)
The ratio (mol%) to the total of (I), (II) and (III ) is shown.

Even when the composition ratio of the structural units (I) to (IV) satisfies the range of the present invention, when the melting point of the above formula (1) is deviated due to a difference in the composition distribution and randomness of the polymer. The fluidity, heat resistance and mechanical properties of the molded article are poor, and the polymer is easily decomposed at a high temperature, and the heat loss is large. Here, melting point (Tm)
Means an endothermic peak temperature observed when measured at a heating rate of 20 ° C./min by a differential scanning calorimeter, and refers to Tm 2 described later.

In the above-described calorimetric measurement, the polymer having undergone the polymerization is treated at room temperature to a temperature equal to or higher than the melting point.
The endothermic peak temperature (hereinafter abbreviated as Tm1) observed when the temperature is measured under the heating condition of ° C./min, and Tm1 +
After holding at a temperature of 20 ° C. for 5 minutes, once cooling to room temperature under a temperature-lowering condition of −20 ° C./min, an endothermic peak temperature (hereinafter referred to as Tm) observed when the temperature is measured again under a temperature-raising condition of 20 ° C./min.
2) is preferably | Tm1−Tm2 | ≦ 10 ° C., and more preferably | Tm1−Tm2 | ≦ 6 ° C. If the temperature difference is too large, the randomness of the polymer cannot be said to be sufficient, which is not preferable.

The logarithmic viscosity of this copolyester is 1.0 to 3.0 dl / g when measured in pentafluorophenol at a concentration of 0.1 g / dl and 60 ° C., and is 1.3 to 2 dl / g. 0.5 dl / g is preferred. When the value of the logarithmic viscosity is less than 1.3 dl / g, the mechanical properties are insufficient,
If it exceeds 3.0 dl / g, the fluidity is impaired, and in either case, it is not preferable.

The molecular weight distribution of the copolymerized polyester of the present invention can be determined, for example, by referring to the Journal of Polymers, Vol. 45, p. 531 (198).
The weight average molecular weight (MW) and the number average molecular weight (M) which can be measured by the method described in 8)
The value of the ratio MW / MN of N) is preferably less than 3.0,
Less than 9 is more preferred. If this value is too large, the randomness cannot be said to be sufficient, which is not preferable.

In order to form the foamed molded article of the present invention, the melt viscosity of the copolymerized polyester is preferably from 100 to 20,000 poise, particularly preferably from 200 to 10,000 poise. The melt viscosity is (melting point (Tm2) +1
0) It is a value measured by a Koka flow tester under the conditions of a shear rate of 1,000 (1 / second) at a temperature of ° C.

In the polycondensation of the copolymerized polyester used in the present invention, in addition to the components constituting the structural units (I) to (IV), 4,4'-diphenyldicarboxylic acid,
3,3′-diphenyldicarboxylic acid, 2,2′-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
4,4'-diphenyl ether dicarboxylic acid, 1,2-
Bis (phenoxy) ethane-4,4′-dicarboxylic acid,
1,2-bis (2-chlorophenoxy) ethane-4,4
Aromatic dicarboxylic acids such as' -dicarboxylic acid and isophthalic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and dodecanedioic acid; alicyclic dicarboxylic acids such as hexahydroterephthalic acid; hydroquinone; -Dihydroxynaphthalene, t-butylhydroquinone, 3,3 ', 5,5'-tetramethyl-
4,4'-dihydroxybiphenyl, phenylhydroquinone, chlorohydroquinone, methylhydroquinone, 4,4'-dihydroxydiphenylsulfone, 4,
Aromatic diols such as 4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylether, 1,4-butanediol, 1,6-hexanediol Aliphatic, alicyclic diols such as neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexane dimethanol, and aromatic hydroxycarboxylic acids such as m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid; Aromatic imide compounds and the like can be further copolymerized in a small proportion that does not impair the object of the present invention.

The foamed molded article of the present invention can exhibit a uniform cell structure by using a copolymerized polyester having a specific structure. However, the foamed molded article of the present invention has a cell fraction of 5 to 50 volumes. %, Preferably 10 to 10%.
30% by volume is preferred. If the bubble fraction is extremely low, the effect of improving the isotropic properties of the liquid crystal polymer is not sufficient,
Conversely, if the cell fraction is too high, the mechanical properties and heat resistance will be impaired, and the size of the cell structure will be non-uniform, so a molded article with uniform mechanical properties may not be obtained. Having.

The method for producing the foamed molded article of the present invention is not particularly limited. One method is to use a foaming agent. In this case, a known foaming agent can be used. Examples of the foaming agent include solvent-type foaming agents such as cyclic hydrocarbons and halogenated hydrocarbons, carbonates such as calcium carbonate and sodium carbonate, decomposition type foaming agents such as azo compounds, nitroso compounds, hydrazine derivatives, tetrazole derivatives, and sulfonyl compounds. Any commonly used foaming agent can be used. The selection of the foaming agent is suitably performed depending on the melting point of the copolymerized polyester, the process temperature, the desired foaming fraction, the foamed structure, and the like.

In addition, a method of introducing a gas such as nitrogen gas or carbon dioxide into a polymer under pressure before foaming the polymer at the time of molding before, during or after the plasticizing of the polymer usually involves foaming. Although there is a problem that a uniform foamed structure is hardly developed, the copolymerized polyester foam of the present invention has a feature that uniform bubbles can be dispersed regardless of the molding method. It can be mentioned as.

The molding method can be any method as long as a molded article having a foamed structure can be obtained, and the molding method is not limited. Preferable examples include extrusion molding, injection molding, press molding, blow molding and the like which are usually performed. The foamed molded product obtained by foaming the copolyester thus formed has little decrease in mechanical properties due to foaming, has excellent uniformity, and has excellent heat resistance, and can be used for various applications as a lightweight engineering material. It is.

By foam-forming the copolymerized polyester (A) of the present invention, a foamed molded article having excellent properties can be obtained. Even better properties can be imparted by subjecting the copolyester composition containing at least one component selected from organic polymer flame retardants and (D) thermoplastic polymers to foam molding.

As the filler (B) to be added to the copolymerized polyester used in the present invention, glass fiber, carbon fiber,
Aromatic polyamide fiber, potassium titanate fiber, gypsum fiber, brass fiber, stainless steel fiber, steel fiber, ceramic fiber, boron whisker fiber, mica, talc,
Examples include fibrous, powdery, granular or plate-like inorganic fillers such as silica, calcium carbonate, glass beads, glass flakes, glass microballoons, clay, wollastenite, and titanium oxide. Among the above fillers, glass fibers can be particularly preferably used. The type of the glass fiber is not particularly limited as long as it is generally used for reinforcing a resin. For example, a long fiber type or a short fiber type chopped strand, a milled fiber or the like can be used. Further, the glass fiber may be coated or bundled with a thermoplastic resin such as an ethylene / vinyl acetate copolymer or a thermosetting resin such as an epoxy resin, or a known coupling agent such as a silane-based or titanate-based coupling agent, or the like. Surface treatment agent. When the filler (B) is added, the addition amount is preferably 200 parts by weight or less based on 100 parts by weight of the copolymerized polyester.
Particularly preferred is 15 to 100 parts by weight.

Further, if necessary, good flame retardancy can be imparted by adding an organic polymer flame retardant (C) to the copolymerized polyester of the present invention.

As the (C) organic polymer flame retardant to be added to the copolymerized polyester used in the present invention, those having a bromine atom in the molecule are preferable, and particularly, the bromine content is 20% by weight.
The above are preferred. Specific examples include brominated polycarbonate (for example, a polycarbonate oligomer produced from brominated bisphenol A or a copolymer thereof with bisphenol A), and a brominated epoxy compound (for example, produced by the reaction of brominated bisphenol A with epichlorohydrin). Monoepoxy compound obtained by the reaction of brominated phenols with epichlorohydrin), poly (brominated benzyl acrylate), brominated polyphenylene ether, brominated bisphenol A, condensate of cyanuric chloride and brominated phenol, bromine Halogenated polymers and oligomers such as brominated polystyrene (brominated polystyrene, polymer of brominated styrene, etc.), cross-linked brominated polystyrene, cross-linked brominated poly α-methylstyrene, etc. And mixtures thereof. Among them, ethylene bis- (tetrabromophthalimide), brominated epoxy oligomer or polymer, brominated polystyrene, cross-linked brominated polystyrene, brominated polyphenylene ether and brominated polycarbonate are preferable, and brominated polystyrene is preferable. It can be particularly preferably used.

The amount of the organic polymer flame retardant to be added is from 0.2 to 30 per 100 parts by weight of the copolymerized polyester (A).
The amount is preferably 0.5 to 20 parts by weight, but the flame retardancy is closely related to the copolymerization amount of the structural unit (III) of the copolymerized polyester (A). It is preferable to add the amount. That is, the amount of the organic polymer flame retardant to be added is preferably from 60 to 280 parts by weight, particularly preferably from 100 to 200 parts by weight, per 100 parts by weight of the structural unit (III) in the copolymerized polyester (A).

The copolymerized polyester (A) of the present invention comprises a structural unit (III) having the structural units (I), (II) and (III)
Since the content is 7 to 20 mol% with respect to the total, a vertical combustion test (ASTM) according to UL94 standard is performed at the above-mentioned flame retardant addition amount.
When the structural unit (III) is less than 7 mol%, the melting point of the copolymerized polyester (A) increases, so that the liquid crystalline polyester is melted by a flame retardant. Is decomposed to cause a decrease in the degree of polymerization, and the addition of a filler is not preferred because the mechanical properties are reduced and the molded product drip when burned. Not only does the heat resistance, such as the deflection temperature under load, significantly decrease, but it is necessary to add a large amount of an organic polymer flame retardant to impart flame retardancy, or further add a flame retardant auxiliary such as an antimony compound. It is necessary, and the heat resistance and the mechanical properties are lowered, which is not preferable.

Further, if necessary, the durability and sliding properties can be improved by adding a thermoplastic polymer (D) to the copolymerized polyester (A) of the present invention.

The thermoplastic polymer (D) to be added to the copolymerized polyester used in the present invention includes polyamide, polyoxymethylene, polycarbonate, polyarylene oxide, polyalkylene terephthalate, and poly-1,4.
-Cyclohexane dimethylene terephthalate, polyarylene sulfide, polysulfone, polyethersulfone, amorphous polyarylate, polyetheretherketone and the like are preferred.

Preferred specific examples of the thermoplastic polymer (D) include the following.

As the polyamide, nylon 6, nylon 46, nylon 66, nylon 610, nylon 1
1, nylon 12, a copolymer thereof, and a binary or ternary copolymer of nylon 6, nylon 66, and hexamethylene isophthalamide containing polyhexamethylene terephthalamide as one component.

Examples of the polyoxymethylene include a polyoxymethylene homopolymer and a copolymer whose main chain is mostly composed of oxymethylene chains.

As the polycarbonate, bis (4-hydroxyphenyl), bis (3,5-dialkyl-4-)
Hydroxyphenyl) or bis (3,5-dihalo-4)
Polycarbonates based on hydrocarbon derivatives containing (-hydroxyphenyl) substitution are preferred and 2,2-
Polycarbonates based on bis (4-hydroxyphenyl) propane (bisphenol A) are particularly preferred.

Examples of the polyarylene oxide include poly (2,6-dimethyl-1,4-phenylene) ether,
2,6-dimethylphenol / 2,3,6-trimethylphenol copolymer, 2,6-dimethylphenol /
2,3,6-triethylphenol copolymer and the like. Styrene-based resins such as polystyrene and high-impact polystyrene can be added to polyarylene oxide.

As the polyalkylene terephthalate,
Examples include polyethylene terephthalate and polybutylene terephthalate.

Examples of the polyarylene sulfide include polyparaphenylene sulfide.

Examples of the polysulfone include those represented by the following structural formula (i).

[0044]

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Examples of the polyether sulfone include those represented by the following structural formula (ii).

[0046]

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Examples of the amorphous polyarylate include those represented by the following structural formulas (iii) to (vi).

[0048]

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Examples of the polyether ether ketone include those represented by the following structural formula (vii).

[0050]

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In the present invention, when the thermoplastic polymer (D) is blended with the copolymerized polyester (A), the amount is from 1 to 200 parts by weight based on 100 parts by weight of the copolymerized polyester.
A weight part is preferable, and 10 to 150 weight parts is more preferable.

In the present invention, the copolymerized polyester (A)
When at least one component selected from (B) a filler, (C) an organic polymer flame retardant, and (D) a thermoplastic polymer is contained therein, it is preferable to carry out melt kneading, and a known method is used for melt kneading. Can be used. For example, the composition can be melt-kneaded at a temperature of 200 to 400 ° C. using a Banbury mixer, a rubber roll machine, a kneader, a single-screw or twin-screw extruder, or the like to obtain a composition.

Further, the composition used in the present invention contains an antioxidant and a heat stabilizer (for example, hindered phenol, hydroquinone, phosphites and substituted products thereof) to the extent that the object of the present invention is not impaired. ), UV absorbers (eg, resorcinol, salicylate, benzotriazole, benzophenone, etc.), lubricants and release agents (eg, montanic acid and its salts, its esters, its half esters, stearyl alcohol, stearamide, and polyethylene wax), dyes ( Eg nigrosine) and pigments (eg cadmium sulfide,
Ordinary additives such as coloring agents including phthalocyanine and carbon black), plasticizers and antistatic agents can be added to impart predetermined properties.

[0054]

The present invention will be further described with reference to the following examples.

Reference Example 1 963.4 g (6.98 mol) of p-hydroxybenzoic acid (I) and 4,4'- were placed in a reaction vessel equipped with a distilling tube and a stirring blade.
125.7 g (0.67) of dihydroxybiphenyl (II)
5 mol), 112.1 g (0.675 mol) of terephthalic acid, 259.4 g (1.35 mol) of polyethylene terephthalate (III) having an intrinsic viscosity of about 0.6, and 935.4 g (9.163 mol) of acetic anhydride And deacetic acid polymerization was performed under the following conditions.

First, the temperature was increased to 250 ° C. in a nitrogen atmosphere at 130 to 150 ° C. for 4 hours, then over 2.5 hours, and the reaction was continued at 250 ° C. for 2.5 hours. Then, after raising the temperature in the system to 300 ° C. over 2 hours,
The pressure inside the system was reduced to 0.3 mmHg over time, and the reaction was continued for further 40 minutes to complete the polycondensation. As a result of the above reaction, a beige polymer (a) having the following theoretical structural formula was obtained.

[0057]

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1 / m / n / o = 77.5 / 7.5 / 15 / 22.5 Further, the polyester was placed on a sample stage of a polarizing microscope, and
As a result of raising the temperature and confirming the optical anisotropy, the liquid crystal onset temperature was 274 ° C., indicating good optical anisotropy. The melting point of this polymer was measured at a rate of temperature rise of 20 ° C./min using a DSC-7 model manufactured by Perkin Elmer Co., Ltd.
1 has a peak temperature of 296 ° C. and Tm 2 has a peak temperature of 29.
4 ° C.

The logarithmic viscosity of this polymer is 1.53 d
1 / g, melt viscosity 304 ° C., shear rate 1000
(1 / sec) was 660 poise.

Reference Example 2 1152 parts by weight of p-acetoxybenzoic acid and 307 parts by weight of polyethylene terephthalate having an intrinsic viscosity of about 0.6 dl / g were charged into a reaction vessel equipped with a stirring blade and a distillation tube. Deacetic acid polycondensation was performed under the conditions.

First, 250 to 320 in a nitrogen gas atmosphere.
After the reaction at 3 ° C. for 3 hours, the pressure was reduced to 1 mmHg, and the reaction was further continued for 5 hours to complete the polycondensation, thereby obtaining a polymer (b) having the following theoretical structural formula.

[0062]

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K / l / m = 80/20/20 This polyester was placed on a sample stage of a polarizing microscope, and the temperature was raised to confirm the optical anisotropy. As a result, the liquid crystal onset temperature was 265 ° C. Further, the melting point (Tm) was 283 ° C. The logarithmic viscosity of the polyester (measured under the same conditions as in Reference Example 1) was 0.68, 293 ° C., and a shear rate of 10
The melt viscosity at 00 / sec was 500 poise.

Reference Example 3 1033 g (5.74 mol) of p-acetoxybenzoic acid (I), 4,4'-diacetoxybiphenyl (II) 51
5.7 g (1.91 mol), 317.1 g of terephthalic acid
(1.91 mol), 259.4 g (1.35 mol) of polyethylene terephthalate (III) having an intrinsic viscosity of about 0.6
Was placed in the same reaction vessel as in Reference Example 1, and subjected to deacetic acid polymerization under the following conditions.

First, at 250 to 330 ° C. in a nitrogen gas atmosphere.
The pressure in the reaction system was reduced to 1.5 mmHg for 3.5 hours, and the reaction was further continued for 1 hour to complete the polycondensation. As a result, a beige polymer (c) having the following theoretical structural formula was obtained. Was done.

[0066]

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1 / m / n / o = 63.75 / 21.25
/15/36.25 Moreover, this polyester was placed on a sample stage of a polarizing microscope,
As a result of raising the temperature and confirming the optical anisotropy, the liquid crystal onset temperature was 274 ° C., indicating good optical anisotropy. The melting point of this polymer was measured at a rate of temperature rise of 20 ° C./min using a DSC-7 model manufactured by Perkin Elmer Co., Ltd.
1 has a peak temperature of 310 ° C. and Tm2 has a peak temperature of 30 ° C.
3 ° C.

The logarithmic viscosity of this polymer is 1.48 d.
1 / g, melt viscosity 313 ° C., shear rate 1000
(1 / sec) was 1300 poise.

Example 1 To 100 parts by weight of the copolymerized polyester (a) obtained in Reference Example 1, 0.5 part by weight of potassium carbonate was added as a foaming agent, and the mixture was supplied to a 30 mmφ twin screw extruder at 300 ° C. After melt-kneading, it was pelletized. The obtained pellets are supplied to Sumitomo Nestal injection molding machine Promat 40/25 (manufactured by Sumitomo Heavy Industries, Ltd.), and a 3 mm-thick tensile test piece is formed under the conditions of a cylinder temperature of 300 ° C. and a mold temperature of 90 ° C. did. When the density was determined from this test piece, it was 1.19 g / cm ³ ,
When the bubble fraction was calculated from this value, it was about 15% by volume. Further, using ten tensile test pieces, AST
A tensile test was performed according to the MD638 standard. The measurement results are shown in Table 2, and it is considered that the variation among the ten test pieces was extremely small and the uniformity of the molded product was high. Examples 2 to 5 and Comparative Examples 1 to 4 (A) Copolyester (a) at the ratio shown in Table 1,
Polymers (b) and (c) outside the scope of the present invention, (B) filler, (C) organic polymeric flame retardant and (D) thermoplastic polymer were added and granulated using a 30 mmφ extruder. .

A foaming agent shown in Table 1 was added to 100 parts by weight of the obtained pellets, and the mixture was subjected to the same injection molding machine as in Example 1 to mold a similar test piece. According to the method, the bubble fraction and the mechanical properties were evaluated. The results are shown in Tables 1 and 2.

[0071]

[Table 1]

[0072]

[Table 2]

Comparative Example 1 shows data of an unfoamed body. In the case of using copolymerized polyesters (b) and (c) other than the copolymerized polyester of the present invention (Comparative Examples 2, 3)
It was found that, compared to the case where the copolymerized polyester of the present invention was used (Example 1), there was a large variation in tensile properties, and that foaming was not performed uniformly.

Further, the copolyester composition obtained by adding (B) a filler, (C) an organic polymer flame retardant and (D) a thermoplastic polymer to the copolyester (a) of the present invention is subjected to foam molding. The foamed molded article also has a small decrease in mechanical properties, and has a uniform foaming state with less variation between molded articles as compared with the case where the copolymerized polyesters (b) and (c) other than the present invention are used. I understand.

[0075]

The foamed molded article of the present invention has greatly improved anisotropy, has isotropic mechanical properties, and has stable mechanical properties. Therefore, it can be used for various applications as a lightweight engineering material. be able to.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08J 9/00-9/42 C08G 63/60 C08K 3/00-3/40 C08L 67/00-67 / 08

Claims (2)

(57) [Claims] 1. It comprises the following structural units (I) to (IV):
The sum of the structural units (I) and (II) is the structural unit (I),
80 to 93 mol% based on the total of (II) and (III) , wherein the structural unit (III) is composed of the structural units (I), (II) and
20 to 7 mol% with respect to the total of (III) , and the molar ratio [(I) / (II)] of the structural units (I) and (II) is 78/2.
The copolymerized polyester (A) having a melt anisotropy of 2 to 93/7, a melting point (Tm, ° C) satisfying the formula (1), and a logarithmic viscosity of 1.0 to 3.0 dl / g. A foam molded article obtained by foam molding. Embedded image -10 <Tm + 5.89x-385.5 <10 ...
(1) configuration (but (1) x in the formula of the structural unit (III)
The ratio (mol%) to the total of the structural units (I), (II) and (III ) is shown. ) 2. The copolymer polyester according to claim 1, which contains at least one component selected from (B) a filler, (C) an organic polymer flame retardant, and (D) a thermoplastic polymer. A foam molded article obtained by subjecting the copolymerized polyester composition to foam molding.