KR20000055347A - polycarbonate/styrene thermoplastic resin composition with good molding properties - Google Patents

Abstract

PURPOSE: Polycarbonate/styrene thermoplastic resin compositions, which are excellent in molding properties and elongation when vacuum molding or blow molding, are provided by adding non-linear structured cyanided vinyl/aromatic vinyl co-polymer to a mixture of polycarbonate and styrene. CONSTITUTION: A resin compositions are produced by adding 0.01-5 parts by weight of co-polymer of non-linear structured aromatic vinyl compounds and cyanide vinyl compounds to 100 parts by weight of mixtures of 50-95wt% of polycarbonate resin and 5-50wt% of rubber enhanced styrene resin. The polycarbonate resin is prepared by reacting divalent phenol compounds and phosgene or diester carboxylate, and the rubber enhanced styrene resin is prepared by mixing 20-100wt% of styrene containing graft co-polymer obtained from graft copolymerization of monomer mixture consisting of 10-50wt% of cyanide vinyl compounds and 50-90wt% of aromatic vinyl compounds and 80-100wt% of styrene containing graft copolymer including 10-50wt% of cyanide vinyl compounds, wherein the rubber enhanced styrene resin is dispersed in polycarbonate resin. The cyanide vinyl/aromatic vinyl co-polymer is consisted of 10-50 parts by weight of cyanide vinyl compounds and 50-90 parts by weight of aromatic vinyl compounds.

Description

Polycarbonate / styrene thermoplastic resin composition with good molding properties

Field of invention

The present invention relates to a polycarbonate / styrene-based thermoplastic resin composition excellent in moldability, and more particularly, by adding a non-linear vinyl cyanide / aromatic vinyl copolymer to a mixture of polycarbonate and styrene, excellent moldability and vacuum forming The present invention relates to a polycarbonate / styrene-based thermoplastic resin composition having excellent stretching characteristics during blow molding.

Background of the Invention

Melt blends of polycarbonate resins and rubber-reinforced styrene resins are excellent in impact resistance, thermal stability, chemical resistance, rigidity, flowability, etc., and can be used in computer monitors, notebook bodies, mobile phones, CD- It is widely used in electronic material parts such as ROM, and its range of use and new uses are steadily developed.

Vacuum molding is a plastic sheet that obtains a product of a desired shape by sheet extruding a resin to first prepare a sheet of sheet, and then softening the sheet in a vacuum molding machine and simultaneously performing vacuum or compression and vacuum to adhere the softened sheet to a mold. It is a kind of molding method. This method is widely used for making inner sheets of refrigerators, etc., and ABS resins are widely used. This is because rubber-reinforced styrene resins such as ABS resins have excellent mechanical properties and processability, as well as excellent appearance and gloss. Polycarbonate resins are excellent in impact strength and weather resistance, and are widely applied as plate materials such as soundproof walls and glass windows.

In general, the polycarbonate resin and the rubber-reinforced styrenic resin are compatible with each other, and thus can be easily processed by various molding methods such as extrusion molding, injection molding, etc., after preparing a blend resin by simply mixing the application. Processed molded articles made of a blend of conventional polycarbonate and rubber-reinforced styrenic resin prepared in this way has the advantage of less physical deviation between the lot (lot) and excellent appearance. However, the size and dispersion degree of the rubber-reinforced styrene resin dispersed in the polycarbonate resin are greatly changed by the processing conditions such as processing temperature, production speed, shear rate, etc. during the molding process. Accordingly, there is a problem that the mechanical properties and appearance of the molded article are greatly changed.

In addition, the existing polycarbonate / rubber-reinforced styrene resin (PC / ABS) has a problem that a lot of defects occur because a lot of thickness deviation occurs when the vacuum molding occurs locally thin parts. In order to solve this problem, compounding a SAN copolymer having a large molecular weight and a large molecular weight distribution can reduce the thickness deviation a little, but due to the high fluidity, the productivity decreases and the color changes due to the extruder overload during compounding and sheet production. There are disadvantages. SAN copolymers with a molecular weight of 1 million or more are sometimes used in general molding processing except vacuum molding, but this process is also difficult to process due to the rapid deterioration of fluidity, and often adversely affects the quality of the final product. .

In the case of manufacturing large molded articles, polyolefins such as low density polyethylene have excellent moldability, but when coating is required, there is a problem in application of the structural material due to low adhesion strength of the coating film, and in the case of modified polyphenylene ether, coating film adhesion and heat resistance are excellent. However, due to poor chemical resistance, stress cracking due to thinners or the like often occurs during painting.

Blends of polycarbonate and rubber-reinforced styrenic resins have excellent coating and plating properties, which are inherent to rubber-reinforced styrene resins, and are easy to paint and plate. However, in the plating process, the dispersion degree of rubber-reinforced styrene resin in the polycarbonate resin must be maintained at an appropriate level to have an excellent level of plated film. If the dispersion degree of rubber-reinforced styrene resin is low, the domain of rubber-reinforced styrene resin is poor. When the size of the increase of the strength of the plated film is significantly lowered. Therefore, in order to maintain the physical balance as described above, it can be said that the dispersion degree and domain size of rubber-reinforced styrene resin in polycarbonate resin are important factors.

Polycarbonate resins and rubber-reinforced styrene, for example, in complex grill structures such as computer monitors, where appearance characteristics are very important, or when processing thin molded parts with complex structures such as notebooks or CD-ROM housings. If the compatibility of the resin is increased, problems such as peeling phenomenon, black lines, flow marks, discoloration is significantly reduced.

Compatibilizers currently used to increase the compatibility of polycarbonate resins and rubber-reinforced styrene resins include styrene-maleic anhydride copolymers, styrene-acrylonitrile-maleic anhydride copolymers, and styrene-methylmethacrylate-maleic anhydride copolymers. And styrene-acrylonitrile-butylacrylate / polybutadiene graft copolymers.

However, these compatibilizers do not have high efficiency and thus have almost no commercialization effect when used in small amounts, and have a problem that the compatibilizers themselves form one domain when used in large amounts. In addition, the appearance of black streaks and deterioration of color stability during processing of injection molding, etc. has not been widely commercialized.

Therefore, the present inventors apply a blend of polycarbonate and rubber-reinforced styrene resin with a copolymer of a non-linear vinyl cyanide / aromatic vinyl compound in order to solve the above problems. Since the molded article is excellent in appearance characteristics, the thickness deviation of the molded article is small, and processed into a sheet form, a polycarbonate / styrene-based thermoplastic resin composition excellent in drawing property in vacuum forming or blow molding has been developed.

An object of the present invention is to provide a polycarbonate / styrene-based thermoplastic resin composition excellent in fluidity.

Another object of the present invention is to provide a polycarbonate / styrene-based thermoplastic resin composition having excellent moldability and excellent color stability due to excellent color stability without black streaks and partial discoloration after injection molding.

It is still another object of the present invention to provide a polycarbonate / styrene-based thermoplastic resin composition having excellent stretching characteristics during vacuum or blow molding after processing into a sheet due to a small thickness deviation of the molded article.

The above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the content of the present invention will be described in detail.

In general, blends of polycarbonate / styrene resins have a domain size of rubber-reinforced styrene resins dispersed in polycarbonate resins during the molding process due to processing conditions such as processing temperature, processing speed and shear rate. And the degree of dispersion is greatly changed, and thus the mechanical properties of the final resin composition and the appearance of the molded article is greatly changed.

In the present invention, in order to improve the properties of the molded product during the molding process of the blended resin in which the polycarbonate and the rubber-reinforced styrene resin are mixed, the copolymer of the non-linear vinyl cyanide compound and the aromatic vinyl compound is made of polycarbonate resin and rubber-reinforced styrene resin. Apply to a mixture of

The blend resin is composed of 50 to 95% by weight of polycarbonate resin and 5 to 50% by weight of rubber-reinforced styrene resin, and is present in a form in which rubber-reinforced styrene resin is dispersed in the polycarbonate resin.

The polycarbonate resin used in the present invention is an aromatic polycarbonate resin prepared by the reaction of a divalent phenol compound with phosgene or diester carbonate. The structure of the divalent phenolic compound is represented by the following formula (I):

In the formula (Ⅰ) A is a single bond, C ₁ ~C ₅ alkylene, C ₂ ~C cycloalkylidene of ₅ alkylidene, C ₅ ~C ₆ a, S or SO _2.

Examples of the dihydric phenol compound represented by formula (I) include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2'-bis (4-hydroxyphenyl) propane, and 1,1'- Bis (4-hydroxyphenyl) cyclohexane and the like. Bisphenols are preferable, and 2,2'-bis (4-hydroxyphenyl) propane, ie, bisphenol A is more preferable. Polycarbonate is prepared by reacting the divalent phenolic compound with phosgene on an interface or in a uniform phase. Polycarbonates having a specific molecular weight can be obtained by controlling the amount of monophenols such as phenol, paracresol, paraisooctylphenol and the like by using a chain terminator. The polycarbonate resin (A) of the present invention has a weight average molecular weight (M _w ) of 10,000 to 200,000, preferably 20,000 to 80,000. Meanwhile, the polycarbonate may be a homopolymer or a copolymer of a dihydric phenol compound.

The rubber-reinforced styrene resin used in the present invention is a styrene-containing graft copolymer obtained by graft copolymerization of a monomer mixture composed of 10 to 50% by weight of a vinyl cyanide compound and 50 to 90% by weight of an aromatic vinyl compound in the presence of rubber. A mixture of 20 to 100% by weight of a resin and 80 to 0% by weight of a styrene-containing copolymer resin having a content of acrylonitrile of 10 to 50% by weight. In addition, the rubber content of the rubber-reinforced styrene resin is preferably 5 to 40% by weight. If the rubber content is 5 wt% or less, the impact strength is lowered, and if the rubber content is 40 wt% or more, there is a problem in that fluidity is lowered.

Examples of the rubber used for the production of the styrene-containing graft copolymer resin include diene rubbers such as polybutadiene, poly (styrene-butadiene), and poly (acrylonitrile-butadiene); Saturated rubber hydrogenated to the diene rubber; Acrylic rubbers such as isoprene rubber, chloroprene rubber, and butyl polyacrylate; And ethylene / propylene / diene monomer terpolymer (EPDM) and the like, but diene rubber is preferred, and more preferably butadiene rubber is suitable.

Acrylonitrile or methacrylonitrile may be used as the vinyl cyanide compound in the graft polymerizable monomer mixture, and styrene, α-methylstyrene, p-methylstyrene, etc. may be used as the aromatic vinyl compound. These are all compounds which can be used for the preparation of styrene-containing copolymer resins.

The copolymer of the non-linear vinyl cyanide / aromatic vinyl compound of the present invention is composed of 10 to 50 parts by weight of a vinyl cyanide compound and 50 to 90 parts by weight of an aromatic vinyl compound, and may also include other monomers copolymerizable therewith. It contains 5 parts by weight or less of the polyfunctional vinyl compound to make the structure. If the content of the vinyl cyanide compound contained in the copolymer resin is less than 10 parts by weight, stress cracking may occur due to paint or thinner, and the appearance of the molded product may be problematic. May occur.

Acrylonitrile or methacrylonitrile may be used as the vinyl cyanide compound, and styrene, α-methylstyrene, or a mixture thereof may be used as the aromatic vinyl compound, and methyl methacrylate or butyl acrylate and the like. The same methacrylic acid ester compound, N-phenylmaleimide, N-cyclohexyl maleimide, maleic anhydride and the like may be copolymerized.

In addition, the polyfunctional vinyl compound used to prepare the nonlinear structure has one or more vinyl structures such as divinyl benzene, glycidyl methacrylate, triaryl isocyanurate, triaryl cyanurate, and cyanide. It is copolymerizable with a vinyl compound and an aromatic vinyl compound by a conventional method.

As a method for producing a vinyl cyanide / aromatic vinyl copolymer having a nonlinear structure, a known method, that is, an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, or the like may be applied. The copolymer is added in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the mixture of the polycarbonate resin and the rubber-reinforced styrene resin.

The resin composition according to the present invention may be prepared by adding a non-linear vinyl cyanide / aromatic vinyl copolymer to a blend of a polycarbonate resin and a rubber-reinforced styrenic resin and adding additives such as heat stabilizers and lubricants commonly used herein. It may be.

The invention will be further elucidated by the following examples which are set forth for the purpose of illustrating the invention and are not intended to limit the scope of the invention. Unless specifically stated below, all parts and percentages refer to parts by weight and weight percent.

Example

The production and specifications of the polycarbonate resins, rubber-reinforced styrene resins and non-linear vinyl cyanide / aromatic vinyl copolymers I and II used as compatibilizers used in Examples and Comparative Examples are as follows.

Polycarbonate Resin (PC Resin)

BAYER's MAKROLON 2800 was used.

Rubber reinforced styrene resin (ABS resin)

SD-0150 of Cheil Industries Co., Ltd. was used.

Preparation of Vinyl Cyanide / Aromatic Vinyl Copolymer I of Nonlinear Structure

150 parts ion exchanged water, 0.4 parts tribasic calcium phosphate, 0.03 parts carboxylic acid anionic surfactant, polyoxyethylene alkyl ether phosphate ester in a mixture of 71% styrene and 29% acrylonitrile Part, and 0.02 part of divinyl benzene were mixed with 0.5 part of 2,2'-azobisisobutylonitrile as an initiator, and then the reactor was completely sealed. After sufficiently stirring and dispersing, the temperature of the reactor was increased to 75 The polymerization was carried out for 6 hours at ℃. After the reaction was completed by cooling the inside of the reactor to room temperature, the obtained polymer was washed, dehydrated, and dried to obtain bead-like copolymer I. The weight average molecular weight of GPC of the copolymer I was 320,000.

Preparation of Nonlinear Polyvinyl Cyanide / Aromatic Vinyl Copolymer II

The preparation was carried out in the same manner as in Copolymer I, except that the amount of divinyl benzene added was 0.1 part. The weight average molecular weight of GPC of the copolymer II was 700,000.

Example 1

PC resin, ABS resin and copolymer I prepared by the above method were mixed at a ratio of 70: 30: 1, 0.4 parts of a conventional heat stabilizer and a lubricant were mixed with 100 parts of the mixture, and each 40 mm in diameter. Pellets were prepared using a twin screw extruder. The manufactured pellets were actually injected into the monitor housing using a computer monitor mold having a general structure, and the appearance of the injection molded product was visually observed to examine the flowable black lines, the presence of partial dichroism, and the moldable temperature range. In addition, 400 mm × 400 mm × 2 mm compression specimens were manufactured by using a press into a pellet, and then a lattice of 50 mm in width and length was displayed on the prepared compression specimens, and then 300 mm (L) through a vacuum molding machine. A vacuum molded article having a diameter of 30 mm (W) and a 200 mm (H) was manufactured. The thickness of the intersection point of the lattice was measured with a thickness gauge with an accuracy of 1/100 mm. Indicated.

Example 2

PC resin, ABS resin and copolymer I prepared by the above method were mixed in a ratio of 70: 30: 5, 0.4 parts each of a conventional heat stabilizer and a lubricant were mixed with 100 parts of the resin, and a biaxial diameter of 40 mm was used. Pellets were prepared using an extruder. It measured by the same method as Example 1, and shows the result in Table 1.

Example 3

PC resin, ABS resin and copolymer II prepared by the above method were mixed in a ratio of 70: 30: 1, and 0.4 parts of a conventional heat stabilizer and a lubricant were mixed with 100 parts of the resin, respectively, and a biaxial diameter of 40 mm was used. Pellets were prepared using an extruder. It measured by the same method as Example 1, and shows the result in Table 1.

Example 4

PC resin, ABS resin and copolymer II prepared by the above method were mixed at a ratio of 70: 30: 5, and 0.4 parts each of a conventional heat stabilizer and a lubricant were mixed with 100 parts of the resin, and a biaxial diameter of 40 mm was used. Pellets were prepared using an extruder. It measured by the same method as Example 1, and shows the result in Table 1.

Comparative Example 1

PC resin and ABS resin were mixed in a ratio of 70:30, 0.4 parts of a conventional heat stabilizer and a lubricant were mixed with 100 parts of the resin, respectively, and pellets were prepared using a twin screw extruder having a diameter of 40 mm. It measured by the same method as Example 1, and shows the result in Table 1.

Item Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Flow black lines radish radish radish radish U Partial Dichroic Occurrence radish radish radish radish U Moldable temperature range (℃) 220 to 260 230-260 235-260 240-265 220 to 260 Thickness (mm) 0.48 0.50 0.49 0.53 0.33 Standard deviation (mm) 0.1 0.1 0.12 0.10 0.26

In the resin compositions of Examples 1 to 4 prepared according to the present invention, the moldability was excellent and black lines or partial discoloration did not occur. In addition, since the case where the minimum thickness is large and the standard deviation is small is excellent in vacuum forming, it can be seen that the resin composition prepared according to Examples 1 to 4 has better vacuum forming than Comparative Example 1.

In the thermoplastic resin composition of the present invention, a thermoplastic resin composition prepared by adding a non-linear vinyl cyanide / aromatic vinyl copolymer to a blend of polycarbonate and rubber-reinforced styrene resin has almost no deterioration in fluidity, and is excellent in moldability. Black molding or partial discoloration does not occur after molding, so the molded article has excellent appearance characteristics, and the thickness variation of the molded article is small. Thus, it has the effect of the invention having excellent stretching characteristics during vacuum molding or blow molding after processing into sheets.

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 (4)

It is prepared by containing 0.01 to 5 parts by weight of a copolymer of a non-linear aromatic vinyl compound and a vinyl cyanide compound with respect to 100 parts by weight of a mixture of 50 to 95% by weight of a polycarbonate resin and 5 to 50% by weight of a rubber-reinforced styrene resin. A polycarbonate / styrene-based thermoplastic resin composition excellent in moldability. The styrene-containing graft of claim 1, wherein the rubber-reinforced styrene resin is obtained by graft copolymerization of a monomer mixture composed of 10 to 50 wt% of vinyl cyanide compound and 50 to 90 wt% of aromatic vinyl compound in the presence of rubber. A mixture of 20 to 100% by weight of copolymer resin and 80 to 0% by weight of styrene-containing copolymer resin having a content of vinyl cyanide compound of 10 to 50% by weight, and the rubber content of the rubber-reinforced styrene resin is 5 to 40% by weight. Polycarbonate / styrene-based thermoplastic resin composition excellent in moldability. The copolymer of the non-linear aromatic vinyl compound and the vinyl cyanide compound is composed of 10 to 50 parts by weight of a vinyl cyanide compound and 50 to 90 parts by weight of an aromatic vinyl compound, and includes other monomers copolymerizable therewith. A polycarbonate / styrene-based thermoplastic resin composition having excellent moldability, characterized in that it comprises a polyfunctional vinyl compound of 5 parts by weight or less to make a nonlinear structure. The compound according to claim 3, wherein the polyfunctional vinyl compound is a compound having at least one vinyl structure selected from the group consisting of divinyl benzene, glycidyl methacrylate, triaryl isocyanurate and triaryl cyanurate. Polycarbonate / styrene-based thermoplastic resin composition.