JPH05320487A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin composition markedly improved in the compatibility of the constituent polyester resin with the constituent polystyrene resin, excellent in moldability and being capable of giving a material excellent in mechanical strengths and heat and chemical resistance. CONSTITUTION:This resin composition is prepared by adding 0.1-20 pts.wt. modified polystyrene resin containing at least one functional group selected from among an acid anhydride group, an epoxy group and an oxazoline group to 100 pts.wt. resin composition comprising 95-5wt.% polyester resin and 5-95wt.% polystyrene resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a polyester-based resin and a polystyrene-based resin as main components, and adds a predetermined amount of a modified polystyrene-based resin containing a group reactive with a hydroxyl group or a carboxylic acid group at the end of the polyester-based resin. By doing so, the compatibility of both can be improved, and good heat resistance,
The present invention relates to a thermoplastic resin composition used for a film sheet or a compound, which has impact resistance, moldability and chemical resistance.

[0002]

2. Description of the Related Art Saturated polyester resins are generally rich in surface smoothness, although they may vary depending on their structure.
It has a glossy appearance. Crystalline PET, PBT
Has a high melting point and high crystallinity, and is widely used for film sheets, molded products, etc., with excellent dimensional stability, transparency, toughness, electrical insulation, and chemical resistance. It has the disadvantage of poor performance. On the other hand, amorphous PC and PAR are excellent in heat resistance, mechanical properties and transparency, and have much better impact resistance than crystalline PET and PBT. However, it has the drawback of poor solvent resistance. On the other hand, polystyrene resins such as PS and AS have excellent moldability, cost and transparency, and are lightweight, so they are used in a wide range of applications such as daily sundries and plastic models. It has the drawback of poor solvent properties. Generally, it is difficult to obtain a resin composition having good properties such as heat resistance, impact resistance, moldability, chemical resistance, etc. from a single resin. A technique called polymer alloy is used in which two or more kinds of resins are combined. However, the compatibility between each resin is usually poor, and it is difficult to obtain a thermoplastic resin having the advantages of each resin because it is not possible to form an incompatible micro phase separation structure simply by mixing them. there were. As a method for improving the compatibility, a method of adding a compatibilizing agent having an affinity to any of the resins to be combined is generally performed, but in the case of polyester resin and polystyrene resin, there is no suitable compatibilizing agent. The improvement effect was insufficient.

[0003]

DISCLOSURE OF THE INVENTION In the present invention, as a result of extensive studies to obtain a compatibilizer having an affinity for both polyester resins and polystyrene resins, it was found that the terminal hydroxyl group or carboxylic acid group of the polyester resin is A modified polystyrene resin containing at least one functional group of an acid anhydride, an epoxy group and an oxazoline group, which is active in the reaction of, significantly improves the compatibility between the polyester resin and the polystyrene resin, and the molding process is performed. It was found that a material having excellent properties, mechanical strength, heat resistance and chemical resistance can be obtained, and the present invention has been completed.

[0004]

That is, according to the present invention, 95 to 5% by weight of a polyester resin and 5 to 5 of a polystyrene resin are used.
With respect to 100 parts by weight of the resin composition consisting of 95% by weight,
It relates to a thermoplastic resin composition comprising 0.1 to 20 parts by weight of a modified polystyrene resin containing at least one functional group selected from an acid anhydride group, an epoxy group and an oxazoline group.

The polyester resin used in the thermoplastic resin of the present invention is not particularly limited and is commercially available. For example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT),
Examples thereof include aromatic polycarbonate, polyarylate, liquid crystal polyester, and copolyester resin obtained by using a plurality of raw material components. These may be used alone or in combination of two or more.

The polystyrene resin used in the thermoplastic resin composition of the present invention is not particularly limited and is commercially available, and examples thereof include polystyrene and acrylonitrile-styrene copolymer. These resins may be used alone or in combination of two or more.

In the present invention, the polyester resin (A) and the polystyrene resin (B) are (A) :( B)
= 95: 5-5: 95 parts by weight, preferably 90:10
It is compounded in the range of 10:90 parts by weight. If the amount of the polystyrene resin compounded is less than 5 parts by weight, the molding processability is insufficiently improved. If the amount of the polyester resin compounded is less than 5 parts by weight, the heat resistance and solvent resistance are not improved. Will be enough.

The modified polystyrene resin of the present invention has at least one functional group selected from the group consisting of an acid anhydride group, an epoxy group and an oxazoline group, which is active in the reaction of the terminal hydroxyl group or carboxylic acid group of the polyester resin. A known radical polymerization method can be applied as a method for synthesizing the modified polystyrene resin, which is a styrene copolymer, and can be easily obtained by solution or suspension polymerization.
The modified polystyrene resin of the present invention has a modification ratio (weight ratio of the functional group-containing monomer at the time of polymerization) of 0.
It is 1 to 20 wt%, preferably 1 to 18 wt%. If the modification rate is less than 0.1 wt%, the effect of improving compatibility cannot be obtained, and if the modification rate exceeds 20 wt%,
Various properties such as moldability deteriorate due to the increase in the molecular weight due to the reaction with the polyester resin. These modified polystyrene resins may be used alone or in combination of two or more.

0.1 to 20 parts by weight of a modified polystyrene resin is mixed with 100 parts by weight of a resin composition in which a polyester resin and a polystyrene resin are mixed at a predetermined ratio, and the resulting mixture is kneaded by a biaxial kneader or the like. As a result, a thermoplastic resin composition having good compatibility can be obtained. If the amount of the modified polystyrene resin blended is less than 0.1 part by weight, the effect of improving the compatibility becomes insufficient, and if the amount of the modified polystyrene resin blended exceeds 20 parts by weight, the compatibility becomes too good and the characteristics deteriorate. Thus, the modified polystyrene resin of the present invention has the effect of significantly improving the compatibility between the polyester resin and the polystyrene resin, and significantly improving the various properties. A graft polymer of a modified polystyrene-based resin and a polyester-based resin is produced by the reaction of a hydroxyl group or a carboxylic acid group at the terminal of the resin with an acid anhydride group, an epoxy group and an oxazoline group.
It is considered that this acts as a surfactant, which improves the compatibility between the polyester resin and the polystyrene resin and enables the formation of an incompatible microphase-separated structure.

The thermoplastic resin composition of the present invention may further contain other compounding agents such as talc, mica, depending on the use and purpose.
Inorganic fillers such as calcium carbonate, wollastonite,
Or reinforcing agents such as glass fiber, carbon fiber, etc.
A flame retardant, a flame retardant aid, an antistatic agent, a stabilizer, a pigment, a release agent, an antioxidant and the like can be added. As a method for producing the thermoplastic resin composition of the present invention, a conventionally known method can be applied, and the raw materials of the thermoplastic resin composition of the present invention are collectively or divided and sufficiently mixed with a Henschel mixer. It can be obtained by further kneading with a biaxial kneader.

[0011]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. << Examples 1 to 5 and Comparative Examples 1 and 2 >> 1000 to 15 were added to the Henschel mixer at the blending ratios shown in Table 1.
Mix for several minutes at 00 rpm, and use a twin-screw kneader for 270
Pellets were prepared by melt-kneading under conditions such that the temperature was up to 280 ° C., and then injection molding was performed, and the obtained test pieces were evaluated for tensile strength, tensile elongation, Izod impact strength and chemical resistance. The evaluation results are also shown in Table 1.

[0012]

* 1: Dianite MA-523V, manufactured by Mitsubishi Rayon Co., Ltd. * 2: Sumibright M192, manufactured by Sumitomo Chemical Co., Ltd. * 3: Oxazoline group-modified polystyrene (modification rate 5 wt.
%) * 4: Oxazoline group-modified polystyrene (modification rate 1 wt
%) * 5: Styrene-maleic anhydride copolymer (modification rate 8w
t%) * 6: Styrene-glycidyl methacrylate copolymer (modification rate 5 wt%) * 7: Measured according to ASTM D-638. * 8: ASTM for 1/4 "width notched test piece
It measured according to D-256. * 9: The tensile test piece was immersed in butyl acetate at 23 ° C. for 3 months, and the change in appearance was observed. In the table, ◯ indicates that it is usable, and Δ indicates that it is slightly eroded or swollen, and x indicates that it is determined to be unusable.

[0014]

As is apparent from the table, in the thermoplastic resin composition of the present invention, the compatibility of the polyester resin and the polystyrene resin is remarkably improved by adding the modified polystyrene resin. It is a new and well-balanced material with excellent heat resistance, impact resistance, moldability and chemical resistance.

Claims (1)

[Claims] 1. A resin composition comprising 95 to 5% by weight of a polyester resin and 5 to 95% by weight of a polystyrene resin based on 100 parts by weight of at least one of an acid anhydride group, an epoxy group and an oxazoline group. A thermoplastic resin composition comprising 0.1 to 20 parts by weight of a modified polystyrene resin containing a functional group.