KR100604088B1 - Thermoplastic Resin Composition of Polycarbonate and Polystyrene Blend - Google Patents

Abstract

The polycarbonate and polystyrene blend resin composition of the present invention comprises (A) 30 to 95% by weight of a polycarbonate resin; (B) 5 to 70% by weight of polystyrene-based or rubber-modified polystyrene resin; (C) It consists of a copolymer of polybutylene terephthalate (PBT) and oxazoline group containing polystyrene.

Compatibilizers, oxazoline group-containing polystyrene (RPS), polybutylene terephthalate, PC / PS blend

Description

Thermoplastic Resin Composition of Polycarbonate and Polystyrene Blend}

Field of invention

The present invention relates to a polycarbonate and polystyrene blend resin composition. More specifically, the present invention relates to a polycarbonate and polystyrene blend resin composition commercialized using a copolymer of polybutylene terephthalate (PBT) and oxazoline group-containing polystyrene (RPS).

Background of the Invention

Bisphenol A polycarbonate (PC) resin is a polymer material having excellent transparency, impact resistance, and heat resistance, and is widely used for compact discs, extrusion sheets, and film. However, the PC has a large change in impact strength depending on the thickness, the impact strength is sensitively changed depending on the sharpness of the notch, and its weak chemical resistance makes it weak in use as a structural material.

U.S. Patent No. 3,239,582 discloses alloys which blend primarily with Acrylonitrile Butadiene Styrene (ABS) resins to compensate for this. PC / ABS blend is an alloy that improves the disadvantages such as low temperature impact resistance, chemical resistance and thickness dependence along with the excellent properties of the existing polycarbonate resin, and is widely used as a resin for electric and electronic products and automotive interior materials.

PC / PS alloys, meanwhile, were developed long ago but have not been widely deployed in the market. This is due to the lack of obvious advantages in price or physical properties over PC / ABS alloys. Recently, however, the market demand for thin wall of electronic product cases and development of environmentally friendly resins is great. In accordance with this market trend, PC / PS alloys having high fluidity and not using halogen-based flame retardants have been developed and compete with existing PC / ABS alloys (Modern Plastics, Feb. 22, 1998).

The main technologies for PC / PS alloy commercialization are commercialization and impact reinforcement technology. PC / PS alloys are basically incompatible blends, which cause phase separation and coalescence in the melt phase, causing problems such as mechanical properties deterioration in the solid phase and exfoliation during injection molding. Commercialization is essential to solve these problems. In addition, it is important to prepare an alloy having good physical balance through the use of an appropriate impact modifier.

In Japanese Patent Laid-Open Nos. 8-239564 and 9-2395650 (Idemitsu Chemical Co., Ltd.), impacts with methyl methacrylate-Butadiene-Styrene (MBS) of core and shell types as compatibilizers A technique for producing a PC / PS alloy to which a phosphorous flame retardant is added using a reinforcing material is disclosed. In addition, Japanese Patent Application Laid-Open No. 8-319387 discloses a technique in which electrochemical uses MBS as a compatibilizer.

In US 3,809,729 (General Electric (GE)), PC / HIPS (High impact polystyrene) is commercialized using PS (oxazoline containing Polystyrene (RPS) including PC containing carboxylic acid groups and oxazoline groups. In US Pat. No. 4,788,238 (Bayer), SMA having good compatibility with PC is used as a compatibilizer for PC / PS alloys.

On the other hand, Japanese Patent Application Laid-Open No. 8-92474 (Asahi Chemical) discloses a styrene acrylonitile copolymer (SAN) having a low content of acrylonitrile (AN) to improve the compatibility of PC / HIPS blends. When phosphorus-based flame retardant is added to it, it has been announced that it can have excellent flame retardancy as well as impact strength of alloy due to high compatibility with the flame retardant.

As described above, many patents for commercialization technology for PC / PS alloys have been filed. Generally, the method of adding a compatibilizer of a third component is widely known as a compatibilization method. As the third component, a copolymer of these two components is mainly used. And when there is a component having a reactive group, a reaction commercialization method such that the reactive group is commercialized through the reaction during processing is used. However, a PC / PS copolymer (Polycarbonate Polystyrene Block Copolymer), which can be used as a three component for PC / PS alloying, is not produced commercially and is known to have considerable difficulty in manufacturing.

For reaction compatibility, it is important to introduce a reactor on each of the PC and PS. However, in the case of PC, the PC resin having a reactive group at the terminal is not commercialized, especially in the case of having a maleic anhydride (MA) or a PC having a carboxylic acid at the terminal, the carbonate of the terminal group and the main chain It may also cause a problem of decomposing PC resin in reaction with the group. By the way, it is known that the carbonate groups of the PC main chain can react very quickly with ester groups, amine groups and epoxy groups. Polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) having ester groups in the molten phase have been reported to easily react with polycarbonates to form random copolymers. It is also reported that amines and epoxy groups also react with carbonate groups in the PC main chain to decompose or form copolymers. Recently, PC / styrenics (commonly known as PC / PS or PC / ABS alloys) has been widely studied as a method of commercializing alloys using reactions with PC main chains. Recently, Wildes et al. (Polymer, 40, 3069, 1999) showed that copolymers can be produced and commercialized by the reaction of amine and carbonate groups when a secondary amine group is introduced on ABS and PC / ABS melt blends.

 On the other hand, in the case of a resin introducing a reactive group on a polystyrene, polystyrene graft glycidyl methacrylate (PS-g-GMA) having an epoxy group and a styrene maleic hydride copolymer having a MA group (Styrene maleic) styrene butadiene styrene copolymer (styrene-Butadiene-Styrene copolymer: SBS-g-MA) grafted with anhydride copolymer (SMA), MA, oxazoline group (Oxazoline containing polystyrene, Reactive Polystyrene: RPS) It is sold.

 On the other hand, reaction commercialization using a polymer having an oxazoline group has been studied by Baker et al. (Polymer Eng. Sci., 27, 1634, 1987). In addition to the studies used for the commercialization of polymer blends using an oxazoline reactor, Many patents have been filed to improve the physical properties of blends. Generally, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), PC, polyphenylene ether (PPE), polyamide (PA), polyethylene (PE), Used in polypropylene (PP). Japanese Patent No. 05,098,103 discloses a technique for adding and commercializing PS (RPS) having an oxazoline group to a PBT / HIPS blend. Since RPS is compatible with HIPS, it exists on PS, and an oxazoline group can react with an acid group of a PBT end group to form a copolymer. Therefore, the copolymers are formed by their reaction during melt blending, and thus commercialized blends can be prepared.

Accordingly, the present inventors prepared a PBT / RPS copolymer using the reaction of PBT and RPS and added it to the PC / PS blend again, thereby forming a copolymer by PBT transesterification with PC to commercialize the PC / PS blend. It is to develop a PC / PS blend resin composition having excellent mechanical properties.

It is an object of the present invention to provide a PC / PS blend resin composition in which a PC / PS alloy which is incompatible is commercialized.

Another object of the present invention is to provide a PC / PS blend resin composition having excellent mechanical properties.

The above and other objects of the present invention can be achieved by the present invention described below.

The polycarbonate and polystyrene blend resin composition of the present invention comprises (A) polycarbonate resin, (B) polystyrene resin or rubber-modified polystyrene resin, (C) polybutylene terephthalate resin and (D) oxazoline-containing polystyrene resin The detailed components of each of these components are as follows.

(A) polycarbonate resin

Processes for preparing polycarbonate resins and their use in thermoplastic resin compositions are well known to those of ordinary skill in the art. Suitable polycarbonate resins are those containing dihydricphenols and phosgene in the presence of molecular weight regulators and catalysts. It can be prepared by coagulation or by using the ester interchange reaction of carbonate precursors such as dihydric phenol and diphenyl carbonate, linear polycarbonate, branched polycarbonate, and polyester carbonate copolymer Include.

The dihydric phenol is preferably bisphenol, and most preferably 2,2-bis (4-hydroxyphenyl) propane called bisphenol A. The bisphenol A can be partially or wholly replaced by another dihydricphenol. Other dihydric phenols include hydroquinone, 4,4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4- Halogenated bisphenols such as hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ether, and 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane and the like.

The polycarbonate resin (PC) used in the preparation of the resin composition of the present invention may be used in the form of a homopolymer, a copolymer, or a mixture thereof.

The linear polycarbonate resin is preferably a bisphenol A-based polycarbonate resin, and the branched polycarbonate may be prepared by reacting a polyfunctional aromatic compound such as trimellitic anhydride and trimellitic acid with dihydroxyphenol and a carbonate precursor. have. The polyester carbonate copolymer is preferably prepared by reacting a bifunctional carboxylic acid with a dihydric phenol and a carbonate precursor.

The molecular weight of the polycarbonate resin is not particularly limited, but the weight average molecular weight is preferably 10,000 to 400,000 in consideration of mechanical properties, workability, and the like of the resin composition.

(B) polystyrene resin or rubber-modified polystyrene resin

Polystyrene resins are prepared by bulk polymerization, suspension polymerization or solution polymerization of aromatic vinyl monomers. Aromatic vinyl monomers include styrene, para methylstyrene, α-methyl styrene and 4-N-propyl styrene, of which styrene and α-methylstyrene are most preferred. The rubber-modified polystyrene resin is reinforced by graft reaction of a vinyl monomer on rubber. Rubber modified polystyrene polymers include butadiene, isoprene, 1,3-heptadiene, methyl-1,3-pentadiene, 2,3-dimethyl-1,3 butadiene, 2-ethyl-1,4-pentadiene and mixtures thereof. Butadiene is preferred.

The polystyrene or rubber-modified polystyrene resin is made by suspension, emulsification and continuous polymerization method, characterized in that the weight average molecular weight is between 80,000 to 400,000, the rubber content of the rubber-modified polystyrene is 5 to 15% by weight is suitable.

The base resin of the present invention comprises (A) 30 to 95% by weight of polycarbonate and (B) 5 to 70% by weight of polystyrene or rubber-modified polystyrene.

(C) copolymer of polybutylene terephthalate and oxazoline group-containing polystyrene

(C1) polybutylene terephthalate

Methods of preparing polybutylene terephthalate resins and their use in thermoplastic resin compositions are well known to those of ordinary skill in the art. Polybutylene terephthalate resins are commercially available from various companies under various trade names and can be prepared using terephthalic acid or dimethyl terephthalate and tetramethylene glycol. Although the molecular weight of the polybutylene terephthalate resin is not particularly limited, the number average molecular weight is preferably 1,000 to 100,000 in consideration of mechanical properties, heat resistance, and the like of the resin composition. In this case, when ethylene glycol (Ethylene Glycol) is used instead of butanediol, polyethylene terephthalate (PET) resin may be used. In addition to the PBT, polyester resins such as PET having a carboxyl end group may also be used. The PBT resin can be a homopolymer or a copolymer using two or more diols or a mixture of such resins.

(C2) oxazoline group-containing polystyrene

A method for producing a polystyrene resin having an oxazoline functional group used in the present invention is introduced in European Patent No. 0146,965, by copolymerization of a styrene monomer with a vinyl group having a cyclic imino ether group. It can manufacture. As cyclic imino ether groups, mainly oxazoline groups are used. When the content of oxazoline is too high, there may be a problem of curing due to reaction between oxazolines during processing. The content of oxazoline is not particularly limited but is preferably 0.5 to 10% by weight, and the oxazoline-containing polystyrene has a weight average molecular weight of 20,000 to 300,000.

The copolymer of (C) polybutylene terephthalate and oxazoline group-containing polystyrene used in the present invention is 5 to 95% by weight of (C1) polybutylene terephthalate and 95 to 5% by weight of (C2) oxazoline group-containing polystyrene. Is prepared by melt mixing using a mixer or an extruder, and suitable for 2 to 20 parts by weight based on 100 parts by weight of (A) + (B).

The method for producing a resin composition of the present invention comprises (A) polycarbonate resin, (B) polystyrene or rubber-modified polystyrene resin, (C1) polybutylene terephthalate resin, and (C2) oxazoline group-containing polystyrene resin in advance in powder state. Or (B) polystyrene / (C1) polybutylene terephthalate blends first, followed by (B) polystyrene or rubber modified polystyrene resins / (C2) oxazoline-containing polystyrene blends. After blending them again, a commercially available polycarbonate / polystyrene blend may be prepared, (C1) polybutylene terephthalate and (C2) oxazoline group-containing polystyrene are first melt mixed and (C) polybutylene terephthalate and oxa A copolymer of a sleepy group-containing polystyrene may be prepared and then blended with (A) and (B).

The resin composition of the present invention may further include a flame retardant, a flame retardant aid, an inorganic additive, a light stabilizer, a plasticizer, a pigment, a dye, a lubricant, a mold release agent, a filler, and an antistatic agent according to each use.

The invention may be better understood by the following examples, which are intended for purposes of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

The specifications of (A) polycarbonate resin, (B) polystyrene or rubber modified polystyrene resin, (C1) polybutylene terephthalate resin and (C2) RPS resin used in the following Examples and Comparative Examples are as follows.

(A) polycarbonate resin

Polycarbonate resin used in the embodiment of the present invention was used bisphenol A type Panlite L-1250W of Teijin, Japan.

(B) polystyrene or rubber modified polystyrene resin

The weight average molecular weight of the polystyrene used in the experiment was Cheil Industries' HF 2660 with 230,000, and the rubber-modified polystyrene resin HIPS used HR 1360 having a butadiene content of about 9%.

(C1) polybutylene terephthalate resin

Polybutylene terephthalate resin used in the embodiment of the present invention is Skyton 1100C of SK Chemical Co., Ltd. in Korea. As for the molecular weight of PBT, a PBT resin having a weight average molecular weight of about 75,000 was used. The content of terminal carboxylic acid is 1.5 mol / 10 ⁶ g.

(C2) RPS resin

As the molecular weight of the RPS resin, an RPS 1005 resin having a weight average molecular weight of about 170,000 was used, and the content of oxazoline group in the RPS resin was 5% by weight.

Impact strength test

Blends were made using a 45 mm biaxial coaxial extruder from SM. The processing temperature was operated by setting the temperature of the extruder cylinder at about 250 ℃, the screw speed was operated at 200 to 400 RPM, discharge amount 30 to 120Kg / hour. The processing method was first put into the PBT resin and RPS resin to extrude to prepare a PBT / RPS copolymer. In this case, the carboxyl group of the PBT end group and the oxazoline group of the RPS react to form a copolymer. However, the reacted blends form very fine morphologies and are incompatible blends, so their reaction occurs mainly at the interface. Therefore, it is thought that there will be a considerable amount of reactive groups remaining without participating in the reaction. However, many have participated in the reaction and contribute to the finer morphology of the blend. The copolymers are then located at the interface and they may function as compatibilizers for the PC / PS blend. After the pellets were made they were added as compatibilizers in the preparation of the PC / PS blend. The blend was prepared in an extruder and then injected to measure physical properties. Injection molds were processed at an injection temperature of 250 ° C. with ASTM family molds.

Table 1 shows the change in impact strength when the PBT / RPS copolymer prepared before is added to a 70/30 blended polycarbonate resin and a polystyrene resin. Examples 1-3 are the case where PBT / RPS copolymer is added, and comparative example 1 is the case where PBT / RPS copolymer is not added.

unit Comparative Example 1 Example 1 Example 2 Example 3 ingredient Polycarbonate (A) weight% 70 70 70 70 HIPS resin (B) weight% 30 30 30 30 PBT / RPS Copolymer Parts by weight (phr) 0 2.5 5 10 Impact strength                                              1/8 "kgcm / cm 6.2 12.5 14.7 9 1/4 "kgcm / cm 2 3.2 4 3.8

As shown in Table 1, the notched impact strength of 1/8 "was about 6.2 kgcm / cm when the PBT / RPS copolymer was not added, but when 2.5 parts by weight of the copolymer was added, 12 It can be seen that the impact strength is increased to about kg · cm / cm. The 1/4 ”impact strength also shows a similar trend.

Tensile Strength Test

PBT / RPS was first prepared in a Haake batch mixer and then added at varying amounts as a compatibilizer for PC / PS blends. Manufacturing conditions produced a melt blend for 10 minutes at 250 ° C. 50 RPM. The PBT / RPS copolymer thus produced showed a very fine morphology of about 100 nanometers in the size of the dispersed phase. It can be seen that this means that the copolymer was prepared through melt blend. The PBT / RPS copolymer thus prepared was added as a compatibilizer for the PC / PS blend. The conditions at the time of melt blend were the same as above. The prepared blend was compression molded in a small mold, and a tensile strength specimen having a gauge length of 40 mm, a width of 10 mm, and a thickness of 1 mm was prepared using a mold having a constant model. Tensile strength specimens were tested at a rate of 1 mm / min with a tensile tester. Table 2 shows the change in tensile strength according to the content of PBT / RPS copolymer.

unit Comparative Example 2 4 Example 5 Example 6 ingredient Polycarbonate (A) weight% 70 70 70 70 PS resin (B) weight% 30 30 30 30 PBT / RPS Copolymer Parts by weight (phr) 0 2.5 5 10 The tensile strength kg · cm / cm ² 405 432 437 495 Elongation % 1.0 1.3 1.4 1.5

The present invention basically commercializes an incompatible PC / PS alloy with PBT / RPS so that PBT forms a copolymer by transesterification with PC, thereby preventing phase separation, delamination and peeling during injection molding. It has the effect of providing a polycarbonate and polystyrene blend resin composition excellent in mechanical properties.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.                     

Claims (10)

(A) 30 to 95% by weight of a polycarbonate resin; And (B) 100 parts by weight of a basic resin composed of 5 to 70% by weight of polystyrene or rubber-modified polystyrene; And (C) 2 to 20 parts by weight of a copolymer of polybutylene terephthalate (PBT) and an oxazoline group-containing polystyrene; The polybutylene terephthalate (PBT) has a weight average molecular weight of 1,000 to 100,000, and a polycarbonate and polystyrene blend resin composition, characterized in that it has a carboxyl end group. [Claim 2] The polycarbonate resin according to claim 1, wherein the polycarbonate resin has a molecular weight range of bisphenol A type aromatic polycarbonate having a weight average molecular weight of 10,000 to 400,000 in a molecular weight measurement method based on polystyrene resin. Polystyrene blend resin composition. The polycarbonate and polystyrene blend resin composition of claim 1, wherein the polystyrene or rubber-modified polystyrene resin is made by a suspension, emulsification, and continuous polymerization method, and has a weight average molecular weight between 80,000 and 400,000. The copolymer of claim 1, wherein the copolymer of polybutylene terephthalate and oxazoline-containing polystyrene is prepared in a molten state by using a mixer or an extruder, and the content of polybutylene terephthalate is in the range of 5 to 95% by weight. The polycarbonate and polystyrene blend resin composition, characterized in that the content of the oxazoline-containing polystyrene has a content of 95 to 5% by weight. The polycarbonate and polystyrene blend resin composition according to claim 4, wherein the polybutylene terephthalate has a weight average molecular weight of 1,000 to 100,000 and a carboxyl group as a terminal group. The polycarbonate and polystyrene blend resin composition according to claim 1, wherein a copolymer of polyethylene terephthalate and an oxazoline group-containing polystyrene is used in place of the copolymer of (C) polybutylene terephthalate and oxazoline-containing polystyrene. The polycarbonate and polystyrene blend resin composition according to claim 4, wherein the oxazoline-containing polystyrene has a weight average molecular weight of 20,000 to 300,000 and an oxazoline group content of 0.5 wt% to 10 wt%. (a) melt mixing polybutylene terephthalate and oxazoline group-containing polystyrene to prepare a copolymer of polybutylene terephthalate and oxazoline group-containing polystyrene; (b) blending the polybutylene terephthalate and an oxazoline group-containing polystyrene (PBT / RPS) copolymer with a blend of polycarbonate resin and polystyrene or rubber-modified polystyrene (PC / PS); Method for producing a commercialized polycarbonate / polystyrene blend resin composition, characterized in that consisting of a step. delete The polycarbonate and polystyrene blend resin composition of claim 1, wherein the resin composition further comprises a flame retardant, a flame retardant aid, an inorganic additive, a light stabilizer, a plasticizer, a pigment, a dye, a lubricant, a mold release agent, a filler, and an antistatic agent. .