JP3011808B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin and a polystyrene resin as a main component. By improving the compatibility of both, good heat resistance,
The present invention relates to a thermoplastic resin composition having good transparency, which is used for a film sheet or a compound having impact resistance, molding processability, and chemical resistance.

[0002]

2. Description of the Related Art Saturated polyester resins are generally rich in surface smoothness, although there are some changes depending on the structure.
It has a glossy appearance. Crystalline PET, PBT
Has a high melting point and a high degree of crystallinity, and has excellent dimensional stability, transparency, toughness, electrical insulation, and chemical resistance, and is widely used for film sheets and molded products. It has the drawback of poor properties. On the other hand, amorphous PC and PAR are excellent in heat resistance, mechanical properties and transparency, and are considerably better in impact resistance than crystalline PET and PBT, and are used for electric and electronic parts, OA equipment, precision machinery, etc. However, it has a drawback of poor solvent resistance.

[0003] On the other hand, polystyrene resins such as PS and AS are extremely excellent in moldability, cost and transparency, and are lightweight, so that they are used for a wide range of uses such as daily goods and plastic models. And has the disadvantage of poor solvent resistance. In general, it is difficult to obtain a resin composition having good properties such as heat resistance, impact resistance, moldability, and chemical resistance from a single resin. A technique called a polymer alloy in which two or more kinds of resins are combined is used. 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 take an incompatible microphase separation structure simply by mixing them. In fact, a material having good transparency has not been obtained. As a method of improving compatibility, a method of adding a compatibilizer having an affinity to any of the resins to be combined is generally performed, but in the case of a polyester resin and a polystyrene resin, there is no suitable compatibilizer. The improvement effect was insufficient.

[0004]

SUMMARY OF THE INVENTION In the present invention, as a result of intensive studies to obtain a compatibilizer having an affinity for both a polyester resin and a polystyrene resin, a hydroxyl group or a carboxylic acid group at the terminal of the polyester resin was obtained. Oxazolone group-containing modified polystyrene resin having high activity in the reaction significantly improves the compatibility between the polyester resin and the polystyrene resin, and found that a material with good transparency can be obtained. Reached.

[0005]

That is, the present invention provides (1) 95 to 5 parts by weight of a polyester resin, (2) 5 to 95 parts by weight of a polystyrene resin, and (3) the polyester resin and the polystyrene resin. 4H-3,1-benzoxazin-4-one-2-one-2-
The modification ratio represented by the following formula by at least one type of modified monomer of (1-methylethenyl) and 2-ethenyl-4,4-dimethyl-5 (4H) -oxazolone is 0.1%.
0.1 to 2% by weight of modified polystyrene resin
It is a thermoplastic resin composition characterized by adding 0 parts by weight. Modified monomer (parts by weight) x 100 Modification rate = ―――――――――――――――――――――――――――― Styrene monomer (parts by weight) + Modification Monomer (parts by weight)

In general, as a technique for obtaining a material having good transparency in a polymer alloy in which two or more kinds of polymers are combined, a material having a close refractive index between the two or a particle size of a domain in an incompatible microphase separation structure is used. There is a method of making finer. As the resin in the present invention,
A thermoplastic resin composition having good transparency can be obtained by using a polyester resin having a very close refractive index and a polyester resin as a base material and further forming an incompatible microphase separation structure in which the domain particle diameter is fine. It is considered possible.

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

[0008] The polystyrene resin used in the thermoplastic resin composition of the present invention is not particularly limited, and is commercially available. For example, polystyrene, acrylonitrile-styrene copolymer, or styrene such as olefin such as butadiene is used. And the like. These resins are used alone or in combination of two or more.

In the present invention, it is more preferable to use a polyester resin and a polystyrene resin having similar refractive indexes. In the present invention, the polyester resin (1) and the polystyrene resin (2) are (1) :( 2) = 95:
5 to 5:95 parts by weight, preferably 90:10 to 10: 9
It is blended in the range of 0 parts by weight. If the amount of the polystyrene resin is less than 5 parts by weight, the improvement of the moldability becomes insufficient. If the amount of the polyester resin is less than 5 parts by weight, the effect of improving the impact resistance and the solvent resistance is reduced. Will be insufficient.

The modified polystyrene resin of the present invention has a structure represented by the following structural formula: 4H-3,1-benzoxazine-
4-one-2- (1-methylethenyl) [formula 1] or 2
-Ethenyl-4,4-dimethyl-5 (4H) -oxazolone [Chemical Formula 2]. As a method for synthesizing the modified polystyrene resin, a known radical polymerization method can be applied, and it can be easily obtained by solution or suspension polymerization.

[0011]

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[0012]

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The modification rate of the modified polystyrene resin of the present invention is 0.1 to 20% by weight, preferably 1 to 18% by weight.
t%. If the modification rate is less than 0.1 wt%, no effect of improving compatibility can be obtained, and if the modification rate is more than 20 wt%, the compatibility becomes too good and various properties deteriorate.

A resin composition 10 in which a polyester resin (1) and a polystyrene resin (2) are blended at a predetermined ratio.
The modified polystyrene resin (3) was added in an amount of 0.1 part by weight to 0 part by weight.
By mixing 1 to 20 parts by weight and kneading with a biaxial kneader or the like, it is possible to obtain a transparent thermoplastic resin composition having good compatibility. When the amount of the modified polystyrene resin is 0.
If the amount is less than 1 part by weight, the effect of improving the compatibility becomes insufficient, and if the amount is more than 20 parts by weight, the compatibility becomes too good and the characteristics are deteriorated.

As described above, the modified polystyrene resin of the present invention has an effect of remarkably improving the compatibility between the polyester resin and the polystyrene resin, and remarkably improving the transparency and other properties. as the reason, by reaction with the polyester terminated in a hydroxyl group or a carboxylic acid group and an oxazolone group such as a resin, to produce the graft polymers of polystyrene resin and polyester resin, which is a surfactant workings It is considered that by doing so, the compatibility between the polyester-based resin and the polystyrene-based resin was improved, and it became possible to obtain an incompatible mocrophase separation structure.

Further, polystyrene resin is inferior in impact resistance, but in order to further improve impact resistance, butadiene resin is used.
An elastomer such as a styrene copolymer, a styrene-butadiene-styrene copolymer, or a polymer obtained by hydrogenating a butadiene portion may be added. Further, the thermoplastic resin composition of the present invention may further contain other additives depending on the purpose and purpose, for example, talc, mica, calcium carbonate, inorganic fillers such as wollastonite, or glass fibers, carbon fibers, and the like. Such a reinforcing agent, a flame retardant, a flame retardant auxiliary, an antistatic agent, a stabilizer, a pigment, a release agent and the like can be compounded.

As a method for producing the thermoplastic resin composition of the present invention, a conventionally known method can be applied. The raw material of the thermoplastic resin composition of the present invention is batch-divided or divided and divided by a Henschel mixer. It can be obtained by sufficiently mixing and kneading with a twin-screw kneader. In the molding process of the thermoplastic resin composition of the present invention, there is not much problem in film extrusion or calendering, but in the case of injection molding or the like, the degree of crystallinity of the crystalline polyester changes due to a cooling process, thereby impairing transparency. In some cases, the mold temperature is preferably set within a range of 30 to 70 ° C.

[0018]

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. << Production Example 1 >> Under a nitrogen stream, styrene 190 parts by weight, 4H-
3,1-benzoxazine-4-ONE-2- (1-methylethenyl) 1
After dissolving 0 parts by weight in 800 parts by weight of benzene, 2 parts by weight of benzoyl peroxide were added, and the mixture was heated with stirring. After performing the reaction at the reflux temperature for 5 hours, it was cooled to room temperature. This was put into methanol / water = 1/1 to precipitate a polymer. The polymer was washed several times with methanol and dried under reduced pressure to obtain a modified polystyrene.
The molecular weight in terms of polystyrene is Mn = 30000, M
w = 60000. << Production Example 2 >> Synthesis was carried out under the same conditions as in Production Example 1 using 2-ethenyl-4,4-dimethyl-5 (4H) -oxazolone. The molecular weight in terms of polystyrene is Mn = 35,000, Mw
= 62,000.

<< Examples 1 to 8 and Comparative Examples 1 to 4 >> Materials having the mixing ratios shown in Tables 1 and 2 were put into a Henschel mixer and mixed at 1000 to 1500 rpm for several minutes. At 270 to 280 ° C. to make pellets, injection molding was performed, and the obtained test pieces were evaluated for tensile strength, tensile elongation, Izod impact strength, and chemical resistance. . Further, a film was prepared by uniaxial extrusion and the haze value was measured. The evaluation results are also shown in Tables 1 and 2.

[0020]

[Table 1]

[0021]

[Table 2]

* 1 Diamond Night MA-523V,
* 2 Diamond Night KR-260, manufactured by Mitsubishi Rayon Co., Ltd. * 3 Sumibright® M192, manufactured by Sumitomo Chemical Co., Ltd. * 4 Clearpet R 1000, manufactured by Sumitomo Nogatack Co., Ltd. * 5 Modified polystyrene of Production Example 1 (modification rate: 5 wt%) * 6 Modified polystyrene of Production Example 2 (modification rate: 5 wt%) * 7 Measured according to ASTM D-638. * 8 Measured according to ASTM D-638. * 9 ASTM for notched specimens of 1/4 "width
It measured according to the method of D-256. * 10 Tensile test pieces were immersed in butyl acetate at 23 ° C. for 3 months, and changes in appearance were observed. In the table, ○ indicates that it was determined that it could be used. Δ indicates that it was slightly damaged or swollen. X indicates that it was determined that it could not be used. * 11 Measured according to ASTM D-1003 (film thickness 250μ).

[0023]

As is clear from the table, the compatibility of the polyester resin and the polystyrene resin is remarkably improved by adding the modified polystyrene resin to the thermoplastic resin composition of the present invention. It is a new, well-transparent, well-balanced material that has the advantages of heat resistance, impact resistance, moldability and chemical resistance.

Claims (1)

(57) [Claims] (1) 95 to 5 parts by weight of a polyester resin, (2) 5 to 95 parts by weight of a polystyrene resin, and (3) a total of 100 parts by weight of the polyester resin and the polystyrene resin, It is represented by the following formula by using at least one modified monomer of 4H-3,1-benzoxazin-4-one-2- (1-methylethenyl) and 2-ethenyl-4,4-dimethyl-5 (4H) -oxazolone. A thermoplastic resin composition comprising 0.1 to 20 parts by weight of a modified polystyrene resin having a modification rate of 0.1 to 20 wt%. Modified monomer (parts by weight) x 100 Modification rate = ―――――――――――――――――――――――――――― Styrene monomer (parts by weight) + Modification Monomer (parts by weight)