JPS6245263B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a polyester resin molded article. More specifically, the present invention relates to a method of producing a molded article having improved physical properties such as heat resistance and mechanical properties by molding an aromatic polyester resin composition containing an inorganic filler and then heat-treating the composition. Polyarylates produced from aromatic dicarboxylic acids and bisphenols have been well known. Polyarylate is a resin that has excellent mechanical properties such as tensile strength, bending strength, and impact strength, as well as heat resistance, chemical resistance, and dimensional stability, and also has a very high heat distortion temperature. Furthermore, an inorganic filler (e.g. glass fiber) is added to the polyarylate180
It is also known that heat treatment at ~350°C further improves heat resistance (Japanese Patent Application Laid-Open No. 52-59653).
Publication No.). However, in this case, since the crystallization rate of polyarylate is extremely slow, the heat treatment time is long, at least 10 minutes, and in particular, it takes 30 minutes or more to fully develop the heat treatment effect, which poses a practical problem. The inventor of the present invention has made extensive studies to improve this point and to more easily obtain an inorganic filler-contained polyarylate molded product having excellent properties.As a result, the present inventors have determined that a specific compound can be mixed into an inorganic filler-contained polyarylate molded product. It has been discovered that the heat treatment time can be dramatically shortened without impairing the heat resistance, and the present invention has been achieved. That is, the present invention provides 100 parts by weight of an aromatic polyester (A) containing terephthalic acid and/or 2,6-naphthalene dicarboxylic acid as the main acid component and an aromatic dihydroxy compound as the main dioxy component,
1 to 100 parts by weight of the inorganic filler (B) and a compound having an aromatic ring that dissolves in the aromatic polyester under melt-mixing conditions, does not substantially react with the aromatic polyester, and is stable. (C)１
In producing a molded article from a resin composition comprising ~50 parts by weight, the resin composition is heated to a temperature higher than the secondary transition temperature of the composition during melt molding or a subsequent step.
This is a heat treatment method for a polyester resin molded body, which is characterized by holding the temperature (°C) below the melting point for 30 seconds to 10 minutes to crystallize it. In the aromatic polyester (A) used in the present invention, 60 mol% or more of its acid component consists of terephthalic acid and/or 2,6-naphthalene dicarboxylic acid, and 50 mol% or more of its dioxy component consists of an aromatic dioxy compound. It is a polyester. Other acid components that can be used in a proportion not exceeding 40 mol% include, for example, isophthalic acid, 2.
Naphthalene dicarboxylic acid other than 6-naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, p-oxybenzoic acid,
Examples include difunctional carboxylic acid components such as 2-methylterephthalic acid, 4-methylisophthalic acid, adipic acid, sebacic acid, hexahydroterephthalic acid, and the like. On the other hand, examples of aromatic dioxy compounds include 2,2-bis(4-hydroxyphenyl)propane [bisphenol A], 1,1-bis(4-hydroxyphenyl)cyclohexane [bisphenol Z], and 1. 1-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane, 1,2-bis(4-hydroxyphenyl)
Ethane, bis(4-hydroxyphenyl)cyclohexylmethane, 3,3-bis(4-hydroxyphenyl)pentane, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)etherhydroquinone, 4. Examples include 4'-dihydroxybiphenyl. One or more types of these can be used. Particularly preferred among these aromatic dioxy compounds are bisphenol A and hydroquinone. Other dioxy components that can be used in a proportion not exceeding 50 mol% include, for example, ethylene glycol, neopentylene glycol, hexamethylene glycol, tetramethylene glycol, trimethylene glycol, cyclohexane dimethylol, tricyclodecane dimethylol, etc. Examples include aliphatic or alicyclic dioxy compounds such as. The method for producing the aromatic polyester may be a well-known method, such as a method in which a dihalide of an aromatic dicarboxylic acid and an alkali metal salt of an aromatic dioxy compound are polymerized by interfacial polymerization, or a method in which a dihalide of an aromatic dicarboxylic acid and an aromatic dioxy compound are polymerized by an interfacial polymerization method. Examples include a method in which a dioxy compound of the group dioxy group is polymerized by a solution polymerization method in an organic solvent such as nitrobenzene, and a method in which a diaryl ester of an aromatic dicarboxylic acid and an aromatic dihydroxy compound are melt-polymerized. Although it may be produced by any method, in the present invention, the aromatic polyester obtained is at least 50 mol% of its repeating units (when one repeating unit is considered as one molecule), preferably 70 mol%. The structures should be mole % identical, more preferably 75 mole % identical. The higher the proportion of the same structure, the greater the effect of the heat treatment of the method of the present invention (improvement in chemical resistance and in particular improvement in heat distortion temperature). Reduced viscosity of aromatic polyester (A) used in the present invention [phenol/tetrachloroethane (60/
40 (measured in a mixed solvent at 35° C. at a concentration of 1.2 g polymer/100 ml solvent) is preferably 0.3 or more in terms of the mechanical strength of the resulting molded product. Next, the inorganic filler (B) used in the present invention is glass fiber, carbon fiber, asbestos, potassium titanate,
It is a general term for fibrous or powdery inorganic fillers such as talc and carbon black, but glass fiber is particularly effective. The average length of the glass fibers is not particularly limited, but is particularly preferably from 0.1 to 10 mm. The inorganic filler (B) used in the present invention is
It is blended in an amount of 1 to 100% by weight, preferably 10 to 90% by weight, and more preferably 20 to 80% by weight based on the aromatic polyester (A). Furthermore, in the present invention, a compound (C) having an aromatic ring is dissolved in the aromatic polyester under melt-mixing conditions with the aromatic polyester, is stable without substantially reacting with the aromatic polyester, and has an aromatic ring. use Here, being stable without reacting with the aromatic polyester under melting conditions means that the compound (C) is Reacts with the aromatic polyester (A) to significantly increase the intrinsic viscosity [η] of the aromatic polyester (A) (for example, reduce [η] to less than 0.3)
This means that the viscosity of the polymer is not significantly increased by causing gelation or the like.
Therefore, compounds with highly reactive ester-forming functional groups (e.g. ester groups, hydroxyl groups, carboxyl groups, etc.), as well as compounds that decompose or gasify at the melting temperature of aromatic polyester, are It's inappropriate. Preferably, the compound (C) has a boiling point of 300°C.
A compound having a boiling point of 320°C or higher is more preferable and does not decompose even at 350°C. Further, the compound (C) is dissolved in the aromatic polyester (A), and does not separate into two layers when, for example, melt-mixed. Specific examples of such compounds (C) include:
The following compounds can be exemplified. Diphenyl sulfone, phenylnaphthalene, phenanthracene, phenylanthracene, triphenylene, triphenylmethane, triphenylbenzene and their aromatic groups include alkyl groups (C _1-6 ), aryl groups (C _6-12 ), nitro Compounds in which a nitro group, halogen, etc. are substituted on the nucleus of diphenyl ether, benzophenone, diphenyl, etc. The mixing ratio of the compound (C) used in the present invention is 1 to 50% by weight based on the aromatic polyester (A). Preferably 3 to 40% by weight, more preferably 5
~30% by weight. The polyester resin composition used in the method of the present invention may optionally contain additives other than inorganic fillers, such as known flame retardants such as halogen-based and phosphorus-based flame retardants, flame retardant aids such as antimony trioxide, antioxidants, Stabilizers, plasticizers, lubricants, antistatic agents, nucleating agents, colorants, etc. can be added. Conventionally known methods can be used to compound and mold the aromatic polyester (A), inorganic filler (B), and compound (C), but a preferred method is to mix the aromatic polyester (A), inorganic filler (B), and compound (C) with an inorganic filler. agent
(B), compound (C), and the various additives mentioned above as needed are dry blended and then directly injection molded, kneaded and extruded using a screw extruder, or especially when the inorganic filler is roving glass fiber. Another method is to impregnate this with molten polyester and draw it out to form a rod-shaped composition, which is then molded. As a molding method, a usual resin molding method can be applied, and injection molding, extrusion molding, press molding, etc. are preferable methods. In the present invention, the resin composition is heat-treated to crystallize it during melt molding or a subsequent step. Whether or not to use a mold at that time is generally selected depending on whether or not the molded article to be heat treated is deformed. This can also be carried out by slow cooling, and such a method is preferred. The heat treatment temperature is within a temperature range of not less than the secondary transition point and less than the melting point of the polyester composition. Preferably, the temperature range is higher than the secondary transition point of the aromatic polyester (A) and lower than the melting point of the composition. Although it is difficult to uniformly determine the composition depending on the composition of the polyester and the composition of the composition,
A particularly preferred treatment temperature is about 160 to 2250°C. The heat treatment time varies depending on the composition, but is 30 seconds to 10 seconds.
It's a minute. Even if the heating time exceeds 10 minutes, the effect of improving heat resistance does not become large. According to the method of the present invention, physical properties of aromatic polyester such as chemical resistance and
In addition to mechanical properties, especially heat distortion temperature of 10℃ or more,
In some cases, the temperature can be improved by more than 50℃. and,
Surprisingly, this heat treatment causes virtually no deterioration in other mechanical or chemical properties of the polyester composition. The present invention will be explained in detail by giving examples below. In the examples, "parts" are based on weight. The reduced viscosity is a value measured at 35° C. by dissolving 1.2 g of polyester in 100 ml of a mixed solvent of phenol/tetrachloroethane (60/40 weight ratio). The heat distortion temperature (°C) was measured by the method specified in ASTM-648 (load: 18.6 kg/cm ² ). Example 1 and Comparative Example 1 305.5 parts of diphenyl terephthalate, 76.4 parts of diphenyl isophthalate, 287.6 parts of bisphenol A
and 0.142 parts of stannous acetate into a reaction vessel,
The reaction was carried out for 60 minutes at normal pressure at °C under a nitrogen atmosphere, and then the pressure was gradually reduced to reach an absolute pressure of 0.5 mmHg or less after 30 minutes.The individualized polymer was taken out and ground into particles of about 20 meshes. This thing has an absolute pressure of 0.5mmHg
Below, 411 parts of aromatic polyester (polyarylate) (reduced viscosity
1.01) was obtained. Next, 100 parts of the polyarylate, 43 parts of glass fiber (diameter 10 μ, length 6 mm) and 20 parts of diphenyl sulfone were mixed, and the cylinder temperature was 360.
It was extruded at ℃ and cut into chips. This chip
After drying for 240 minutes at 120℃ and an absolute pressure of 0.5mmHg or less,
Molding was carried out at a cylinder temperature of 350°C and a mold temperature of 200°C. At this time, the heat treatment time in the mold was set to 2 minutes. The resulting molded article had a heat distortion temperature of 280° C. or higher, a bending strength of 2900 Kg/cm ² , and a tensile strength of 1750 Kg/cm ² . As a comparison, when an experiment similar to the above was conducted without adding any diphenyl sulfone, the molded product did not crystallize at all and the heat distortion temperature was as low as 183°C. The bending strength was 1600 Kg/cm ² and the tensile strength was 1400 Kg/cm ² . Moreover, there was almost no change even when the heat treatment time was 10 minutes. Example 2 and Comparative Example 2 A mixture of 441.6 parts of 2,6-naphthalene dicarboxylic acid diphenyl ester, 287.6 parts of bisphenol A, and 0.12 parts of titanium tetrabutoxide was reacted in the same manner as in Example 1 to form an aromatic polyester.
580 parts (reduced viscosity 0.94) were obtained. 580 parts of this polyester, 387 parts of glass fiber (same as above) and 145 parts of trichlorodiphenyl were mixed, extruded at a cylinder temperature of 370°C, and cut into chips. Next, after drying this chip, the cylinder temperature is 300℃.
Injection molding was performed at a mold temperature of 240°C and a molding cycle of 4 minutes (including 3 minutes of heat treatment time). The molded product obtained did not deform even at 280℃ (heat distortion temperature > 280℃).
℃). For comparison, when molding was performed in the same manner as above without adding any trichlorodiphenyl, the heat distortion temperature of the molded product was 200°C. Example 3 and Comparative Example 3 191 parts of diphenyl terephthalate, 116 parts of bisphenol A, 16.5 parts of hydroquinone and 0.071 parts of stannous acetate were reacted in the same manner as in Example 1 to produce polyester 190 with a reduced viscosity of 1.10.
I got the department. This polyester has glass fiber (diameter
10μ, length 6mm) and 19 parts of triferylene were mixed and molded in the same manner as in Example 2. For comparison, molding was also carried out in the same manner as above without adding triphenylene. The heat deformation temperature, bending strength and tensile strength of the obtained molded product were as shown in Table 1.

[Table] Examples 4 to 7 When the mixing ratio of diphenyl terephthalate and diphenyl isophthalate was changed as shown in Table 2 in Example 1 (Examples 4 to 5), and when diphenyl isophthalate was not used. The amount of diphenyl terephthalate is 382 parts, and the amount of bisphenol A is
When using 260.0 parts and the specified amount of glycol shown in Table 2 (Examples 6 and 7), 100 parts of each polyester, 35 parts of glass fiber (same as Example 1) and the compound shown in Table 2 were added. A predetermined amount of (C) was mixed and then injection molded in the same manner as in Example 1 except that the mold temperature and heat treatment time shown in Table 2 were used. The results are shown in Table 2.

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Claims (1)

[Claims] 1 100 parts by weight of an aromatic polyester (A) containing terephthalic acid and/or 2,6-naphthalene dicarboxylic acid as the main acid component and an aromatic dihydroxy compound as the main dioxy component, inorganic filler (B) 1-100 parts by weight
parts by weight and under melt-mixing conditions with the aromatic polyester, and is stable without substantially reacting with the aromatic polyester;
When producing a molded article from a resin composition consisting of 1 to 50 parts by weight of a compound (C) having an aromatic ring, the resin composition is heated to a temperature higher than the secondary transition temperature of the composition during melt molding or a subsequent step. Temperature below melting point (℃)
1. A method for producing a polyester resin molded article, which comprises crystallizing it by holding it for 30 seconds to 10 minutes.