KR930010235B1 - Polyester/polycarbonate alloy resin composition - Google Patents

Abstract

The polyester/polycarbonate alloy resin compsn. is composed of 20- 65 wt.% polyester copolymer comprising aromatic dibase acid, C2-4 glycol cpd. and aliphatic dimer acid, 30-70 wt.% aromatic polycarbonate, and 5-30 wt.% polybutadiene/vinyl monomer-grafted copolymer as an impact-resistant reinforcing material. The aromatic dibase acid is pref. terephthalic acid or dimethylterephthalate, the glycol cpd. is pref. ethylene, propylene or butylene glycol, the polycarbonate is composed of bisphenol-A and phosgen, and the grafted copolymer is pref. MBS, SBS, SEBS or ABS copolymer. The alloy resin compsn. has a good moldability, impact, heat and weather resistance.

Description

Polyester / Polycarbonate Alloy Resin Composition

The present invention relates to a polyester / polycarbonate alloy resin composition which is a thermoplastic resin composition having excellent mechanical properties and moldability, and more particularly, has excellent moldability and impact resistance, and at the same time, heat resistance, weather resistance, chemical resistance, electrical insulation, and paintability. The present invention relates to a resin composition which is an excellent polyester / polycarbonate resin alloy (ALLOY).

Generally, polyester resins represented by polyalkylene terephthalates, such as polyethylene terephthalate and polybutylene terephthalate, are resins having excellent mechanical strength, heat resistance, electrical insulation, and chemical resistance, either alone or as reinforcing agents such as glass fibers. It is widely used as a fiber, film, plastic molded article by mixing or modifying and other additives.

However, such polyester resins have excellent physical properties as described above, but their use has been limited in fields requiring high impact resistance because they have very poor impact resistance in the presence of a notch.

On the other hand, aromatic polycarbonate resins such as bisphenol-A-type have excellent impact resistance, thermal stability, fatigue resistance, and high mechanical strength, but are poor in chemical resistance and weather resistance, and are in the range of 1/2 to 1/4 Above the critical thickness of has a disadvantage that the impact strength is sharply lowered.

Efforts have been made so far to make use of the advantages of the two resins by mixing, that is, alloying a polyester resin and a polycarbonate resin having such characteristics, and to compensate for the disadvantages.

As such, representative examples of alloying polyester and aromatic polycarbonate resin to produce a resin mixture having excellent properties include Japanese Patent Application Laid-Open No. 53-129246, US Patent Nos. 4,161,469, 4,180,494 and No. 4,654,400.

Japanese Laid-Open Patent Publication No. 53-129246 discloses 5 to 94% by weight of a saturated polyester resin (A); Aromatic hydrocarbon monomer and methacrylic acid in the presence of 5 to 94% by weight of polycarbonate resin (B) and a rubbery polymer mainly composed of alkyl acrylate and / or alkyl methacrylate having an alkyl group having 2 to 10 carbon atoms. A thermoplastic resin composition having excellent moldability and excellent mechanical and thermal properties, comprising 1 to 40% by weight of a resin polymer obtained by polymerizing at least one ester monomer or a mixture of this and other vinyl monomers as a main component. Is disclosed.

On the other hand, U.S. Patent No. 4,161,469 discloses a polymer mixture composed of a polyalkylene terephthalate resin and an organopolysiloxane-polycarbonate block copolymer having a higher impact strength than this resin, whereby impact resistance and thermal deformation are improved. have.

In addition, U.S. Patent No. 4,180,494 discloses a high impact resistance and solvent resistance comprising a residual amount of core-shell polymer polymerized from about 25 to 95% by weight of an aromatic polyester and a monomer consisting of about 1 to 8% by weight of an aromatic polycarbonate and butadiene. A resin composition having the same is disclosed.

In addition, US Patent No. 4,654,400 discloses 30 to 70% by weight of aromatic polycarbonate (a) and 20 to 60% by weight of aromatic polyester (b); In a polymer mixture consisting of 5-15% of a polymer (c) having an elastic core made of at least one alkyl acrylate or aralkyl acrylate, a crosslinking agent and a grafting agent and a rigid thermoplastic sheath, the average particle size of the polymer (c) A polymer mixture is disclosed which has a good impact strength and tensile strength and is not discolored by a solvent, characterized by being 0.2 µm or less.

However, although the resin compositions as described above have some improvement in mechanical strength, chemical resistance, heat resistance, etc., the impact resistance of the composition cannot be sufficiently increased, or the flowability during molding is very poor, which is not suitable for molding thin parts. However, there is still a disadvantage that the impact strength is lowered as the thickness of the polycarbonate resin increases.

Accordingly, the present inventors, unlike the conventional method, to prepare a resin composition excellent in mechanical properties and moldability, modified polyester resins, that is, polyester copolymers containing dimer acid (dimer acid) and aromatic polycarbonate resin The present invention was found by adding and kneading a graft copolymer composed of a polybutadiene and a vinyl monomer as an impact reinforcing material to the resin composition, thereby obtaining a resin composition having excellent impact resistance and moldability and almost no difference in impact strength according to thickness. It was completed.

In general, in order to maximize the physical properties of the polymer blend (polymer blend) prepared by alloying two or more polymers, it is desirable to appropriately control the microstructure of the composition.

That is, it is preferable to adjust the domain size and the technology to promote compatibility between the constituent composition. In the present resin composition, the polyester copolymer containing dimer acid further improves the dispersibility and compatibility of the graft copolymer used as the impact reinforcing material, and adjusts the melt viscosity of the composition appropriately. In this case, it is possible to produce a resin composition having excellent mechanical properties and processability.

Therefore, it is an object of the present invention to provide a thermoplastic resin composition which alloys two or more polymers and has excellent moldability and impact resistance, as well as excellent heat resistance, weather resistance, chemical resistance, electrical insulation, and paintability.

In order to achieve the above object, the present invention is composed of a polybutadiene / vinyl monomer which is an impact reinforcing material of 20 to 65% by weight of a polyester copolymer containing dimer acid and 30 to 70% by weight of an aromatic polycarbonate. 5-30% by weight of the graft copolymer is added and mixed to provide a thermoplastic resin composition. The polyester copolymer used in the present invention is composed of an aromatic dibasic acid, a glycol compound having 2 to 4 carbon atoms, and a dimer acid. Preferred aromatic dibasic acids include terephthalic acid, dimethyl terephthalate and the like, and examples of the glycol compound include ethylene glycol, propylene glycol, butylene glycol and the like. In addition, the dimer acid used in the present invention is characterized in that it is prepared by dimerization of 18 linear aliphatic acids containing 18 carbon atoms containing unsaturated double bonds such as oleic acid, linoleic acid, linolenic acid, etc. Detailed preparation of the acid is disclosed in U.S. Patent No. 2,347,562, and the commercially available product is EMEROL Co., Ltd. (EMPOL).

On the other hand, the dimer acid prepared by dimerization of linear aliphatic acid contains not only dimers but also monomers and trimers, in which case the content of monomers and trimers is preferably 5% by weight or less. It is preferable that content of the dimer acid in a polyester copolymer is 1-20 weight% with respect to an aromatic dibasic acid. When the content of dimer acid is less than 1% by weight, the effect of addition is insignificant, and when the content is more than 20%, a problem of lowering the strength of the composition occurs. The said polyester copolymer can be manufactured by esterifying or ester substitution reaction of aromatic dibasic acid and dimer acid using a glycol compound. On the other hand, it is preferable to make content of the polyester copolymer in the whole composition into 20 to 65 weight%. When the content of the polyester copolymer is less than 20% by weight, the chemical resistance, weather resistance of the composition is reduced, and when the content is more than 65% by weight, the problem of reducing the impact strength occurs.

On the other hand, the aromatic polycarbonate used in the present invention is composed of bisphenol-A- and phosgen (phosgen) and derivatives thereof, and it is preferable to select and use the intrinsic viscosity in the range of 0.4 to 1.0 in methylene chloride at 25 ° C. The content of the aromatic polycarbonate in the total composition is preferably 30 to 70% by weight.

When the content of the aromatic polycarbonate is less than 30% by weight, a problem occurs that the impact strength is reduced when the composition is increased in thickness, and when the content exceeds 70% by weight, a problem of reducing the chemical resistance and weather resistance of the composition occurs. .

On the other hand, the graft copolymer composed of polybutadiene / vinyl monomer used as the impact reinforcing material in the present invention is a graft copolymer composed of butadiene polymer and at least one vinyl monomer. Examples of the vinyl monomers include alkyl methacrylates having 1 to 4 carbon atoms, aromatic monovinyl compounds, and vinyl cyanide compounds. Specific examples of the aromatic monovinyl compound include styrene, vinyltoluene and methyl styrene. Examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile and acrylonitrile chloride. Such graft copolymers can be prepared by conventional bulk polymerization, suspension polymerization, and emulsion polymerization. Examples of the graft copolymers include methyl methacrylate-butadiene-styrene (MBS) copolymers, styrene-butadiene-styrene (SBS) copolymers, styrene-ethylene-butadiene-styrene (SEBS) copolymers and acrylonitrile -Butadiene-styrene (ABS) copolymer.

In particular, the graft copolymer used in the present invention is preferably a butadiene content of 50% by weight or more. On the other hand, the content of the graft copolymer, which is an impact reinforcing material, with respect to the total composition is preferably 5 to 30% by weight. When the content of the graft copolymer is less than 5% by weight, the effect of addition is insignificant, and when the content is more than 30% by weight, problems of deterioration in strength and flowability of the composition occur.

On the other hand, the resin composition according to the present invention is within the scope and spirit of the present invention within the scope of the present invention, fibrous reinforcement or granular inorganic materials, release agents, heat-resistant agents, colorants, weathering agents, flame retardants, agents Premises and the like may be added, and the resin composition according to the present invention may be used for general injection or extrusion.

On the other hand, the resin composition according to the present invention having the composition as described above may be prepared by the following method.

A sufficiently dried polyester copolymer, an aromatic polycarbonate and a graft copolymer are mixed and melt kneaded in an extruder heated to 260 to 270 ° C. to prepare chips. In this case, a single screw or twin screw extruder may be used, but in order to sufficiently disperse the composition, it is preferable to use a twin screw extruder, and in order to prevent thermal decomposition of the resin composition, it is preferable to minimize the residence time in the extruder.

Hereinafter, preferred embodiments of the present invention are described. However, the following examples are only for illustrating the present invention in more detail, and the present invention is not limited to these examples.

In addition, the characteristic of the resin composition manufactured by the following Example was evaluated by the following evaluation methods.

(1) tensile strength

Dumbbell-type specimens were fabricated and measured according to A BTM D 638.

(2) impact strength

In accordance with ASTM D256, 1/4 ＂and 1/8＂ specimens were prepared to measure Izod and notched impact strength.

(3) resin flowability

Melt Flow Rate (Melt Index, MI) was measured at 280 ° C. according to ASTM D1238.

EXAMPLE

Preparation Example 1

Preparation of Polyester Copolymer Containing Dimer Acid

95 parts by weight of dimethyl terephthalate (DMT), 5 parts by weight of <EMPOL 1009> which is a dimer acid, and 0.18 parts by weight of tetrabutyl titanate as a catalyst of 180 parts by weight of 1,4-butanediol (BD) in a mixer, followed by nitrogen After stirring for 40 minutes at 255 ° C. (first reaction temperature) under an atmosphere, the temperature was raised to 270 ° C. (second reaction temperature), and the polymerization was carried out for 4 hours by reducing the pressure in the tube to 0.5 mmHg. The internal pressure of the tube was reduced to normal pressure using nitrogen, and then discharged to obtain a pellet-shaped copolymer. The intrinsic viscosity of the polyester copolymer thus obtained was measured in a 25 ° C. phenol / chlorine tetrachloride (3/2) solution, and the melting point was measured using a differential thermal analyzer. The polyester copolymer prepared in Production Example 1 was referred to as (A), and the physical properties thereof were measured and shown in Table 2 below.

[Production Examples 2 to 4]

Investigation of the Changes in Properties of Dimer Acids in Polyester Copolymers

A polyester copolymer was obtained by polymerization in the same manner as in Preparation Example 1, except that the mixing ratio of D MT, dimer acid and BD was changed to the composition shown in Table 1 below. In this case, the prepared polyester copolymers are referred to as (B), (C) and (D), respectively, and the physical properties thereof are shown in Table 2 below.

TABLE 1

TABLE 2

Example 1

40 wt% of the polyester copolymer (A) prepared in Preparation Example 1, 45 wt% of the bisphenol-A polycarbonate resin, and 15 wt% of the methyl methacrylate-butadiene-styrene copolymer were added and mixed in the mixer. Next, it was melt kneaded in a twin screw extruder heated to 265 ° C. to prepare chips. The chip was then dried in a 120 ℃ hot air dryer for at least 5 hours, and the melt flow rate was measured at 270 ℃. Dumbbell type, 1/8 ＂, and 1/4 하여 specimens were used using a screw injection machine heated to 265 ℃. After fabrication was carried out to measure the mechanical properties by the above measurement method. Measured physical properties are shown in Table 4 below.

EXAMPLES 2-7

In order to investigate the effect of the composition change, the mixing ratio of the polyester copolymer, bisphenol-A polycarbonate and methyl methacrylate-butadiene-styrene copolymer was changed to the composition as shown in Table 3 below. Except for the points, the resin composition of the present invention was obtained by the same method as in Example 1 above. The physical properties of these resin compositions were measured and the results are shown in Table 4 below.

Comparative Examples 1-3

For comparison with the resin composition of the present invention, polybutylene terephthalate having an intrinsic viscosity of 0.85 was used in place of the copolyester used in the present invention, except that the composition was shown in Table 3 below. The resin composition was obtained by treating in the same manner as in the above-described example, and the physical properties thereof were measured and shown in Table 4 below.

TABLE 3

Note) MBS copolymer: Methyl methacrylate-butadiene-styrene copolymer (trade name: KCA-102 'manufactured by Kureha Chemical Co., Ltd.)

TABLE 4

Claims (2)

20 to 65% by weight of a polyester copolymer composed of an aromatic dibasic acid, a glycol compound having 2 to 4 carbon atoms, and 1 to 20% by weight of an aliphatic dimer acid relative to a dibasic acid, and an aromatic polycarbonate 30 to A polyester / polycarbonate alloy resin composition comprising 70% by weight and 5 to 30% by weight of a graft copolymer obtained from polybutadiene / vinyl monomer as an impact reinforcing material. The polyester / polycarbonate alloy according to claim 1, wherein the dimer acid is prepared by dimerization of 18 linear aliphatic acids containing 18 carbon atoms including unsaturated double bonds such as oleic acid, linoleic acid, linolenic acid. Resin composition.