KR20020014292A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE: A thermoplastic resin composition and a molded product prepared by using the composition are provided, to improve the low temperature impact resistance, the heat stability, the workability, the appearance and the compatibility and to prevent the deterioration of the mechanical properties in hot injection. CONSTITUTION: The composition comprises (A) 45-95 parts by weight of polycarbonate resin; (B) 1-50 parts by weight of a rubber-modified grafted copolymer resin which is obtained by grafting 5-95 wt% of a mixture of 5-95 parts by weight of styrene, α-methylstyrene, halogenated or alkyl styrene or their mixtures and 5-50 parts by weight of acrylonitrile, methacrylonitrile, methacrylic acid alkyl ester of C1-C8, methacrylic acid ester of C1-C8, maleic anhydride, alkyl (C1-C4) or phenyl N-substituted maleimide or their mixtures, to 5-95 wt% of a copolymer selected from the group consisting of butadiene rubber, acryl rubber, ethylene-propylene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, isoprene rubber, ethylene-propylene-diene terpolymer, polyorganosiloxane-polyalkyl(meth)acrylate rubber and their mixture; (C) 0.5-50 parts by weight of a styrene-based copolymer which is obtained by copolymerizing 50-95 parts by weight of styrene, α-methylstyrene, halogenated or alkyl styrene or their mixtures and 5-50 parts by weight of acrylonitrile, methacrylonitrile, methacrylic acid alkyl ester of C1-C8, methacrylic acid ester of C1-C8, maleic anhydride, alkyl (C1-C4) or phenyl N-substituted maleimide or their mixtures; and (D) 0.5-30 parts by weight of an amine group-containing styrene-based copolymer resin which is obtained by copolymerizing 50-95 parts by weight of styrene, α-methylstyrene, halogenated or alkyl styrene, methacrylic acid alkyl ester of C1-C8, methacrylic acid ester of C1-C8 or their mixtures, with 5-50 parts by weight of acrylonitrile, methacrylonitrile or their mixture in the presence of 0.01-1.0 parts by weight of an amine group-containing free radical polymerization initiator.

Description

Thermoplastic Resin Composition

Field of invention

The present invention relates to a polycarbonate-based thermoplastic resin composition having improved compatibility. More specifically, the present invention relates to a thermoplastic resin composition comprising a polycarbonate resin, a rubber-modified styrenic graft copolymer resin, a styrene copolymer resin and an amine group-containing styrene copolymer resin.

Background of the Invention

Polycarbonate resins are excellent in transparency, mechanical strength as well as heat resistance, and are widely used in applications such as electric, electronic products, and automobile parts. However, polycarbonate resins are used in combination with other types of resins due to their low notch impact strength and poor processability. For example, blends of polycarbonate / styrene-containing copolymers have improved notch impact strength while maintaining high notch impact strength. It can be referred to as a resin mixture. However, when the blend of the polycarbonate / styrene-containing copolymer stays at a high temperature during the extrusion or injection process, the domain size of the components constituting the dispersed phase is increased, which is a continuous phase ( When the viscosity of the resin forming the matrix is lowered, it is more easily generated. As the phase size of the components constituting the dispersed phase increases, the mechanical properties of the molding rapidly decrease, and in particular, the low temperature impact resistance rapidly decreases.

U. S. Patent No. 5,292, 786 discloses a resin composition having improved weld-line strength composed of polycarbonate resin, ABS resin, phosphorus flame retardant and polyalkyl methacrylate resin. However, in the above technique, when the polyalkyl methacrylate resin is used in an appropriate amount or more, the thermal stability and appearance characteristics of the resin composition may be degraded due to decomposition (or depolymerization) of the polyalkyl methacrylate resin.

U.S. Patent Nos. 5,373,065 and 5,552,480 disclose techniques for introducing amine groups into styrene or olefinic resins and examples of using such resins to improve the compatibility of resin compositions. However, this technique is limited in practical commercial use due to the complicated procedure of introducing amine groups into the resin and the difficult production conditions.

US Pat. No. 5,910,538 also discloses a technique of using a compatibilizer in which a secondary amine group is introduced into a styrene resin copolymerized with maleic anhydride or the like in order to improve compatibility of a polycarbonate resin and a vinyl polymer. However, the above technique also uses a method of introducing an amine group to a pre-prepared resin through a method such as extrusion, which is difficult to use commercially because the procedure is complicated and the manufacturing conditions are difficult.

On the other hand, the inventors of the present invention, in order to overcome the above problems, a styrene-based air prepared using an amine group-containing free radical initiator as a compatibilizer in a composition composed of a polycarbonate resin, a rubber-modified styrenic graft copolymer, and a styrene copolymer By adding a copolymer resin, a thermoplastic resin composition having excellent balance of physical properties such as impact resistance at low temperature, thermal stability, heat resistance, workability and appearance, without deterioration in mechanical properties such as impact strength of a molded product at high temperature injection, is exhibited. It is early to develop.

An object of the present invention is to provide a thermoplastic resin composition that does not exhibit a decrease in mechanical properties such as impact strength of the molded product at high temperature injection.

Another object of the present invention is to provide a thermoplastic resin composition having excellent low temperature impact resistance.

Still another object of the present invention is to provide a thermoplastic resin composition having excellent balance of physical properties such as thermal stability, heat resistance, workability and appearance.

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

The thermoplastic resin composition of the present invention comprises (A) polycarbonate resin, (B) rubber modified styrene graft copolymer resin, (C) styrene copolymer resin and (D) amine group-containing styrene copolymer resin. Detailed description of each of these components is as follows.

(A) polycarbonate resin

The polycarbonate resin of the present invention is prepared by reacting diphenols represented by the following general formula (1) with phosgene, halogen formate or diester carbonate as an aromatic polycarbonate containing no halogen:

Wherein A is a single bond, alkylene of C _1-5 , alkylidene of C _2-5 , cycloalkylidene of C _5-6 , S or SO ₂ .

Examples of the diphenols represented by the formula (1) include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis- (4-hydroxyphenyl) -propane, and 2,4-bis- (4-hydroxyphenyl) -2-methylbutane, 1,1-bis- (4-hydroxyphenyl) -cyclohexane, 2,2-bis- (3-chloro-4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane etc. are mentioned. Among them, 2,2-bis- (4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane, 1,1-bis- (4- Bisphenols, such as hydroxyphenyl) -cyclohexane, are preferable, and 2,2-bis- (4-hydroxyphenyl) -propane also called bisphenol-A is the most preferable.

The polycarbonate resin (A) of the present invention has a weight average molecular weight (M _w ) of 10,000 to 200,000, preferably 15,000 to 80,000. The branched polycarbonate resin may be used, and preferably, may be prepared by adding a compound having 0.05 to 2 mol% of a trivalent or more phenol group based on the total amount of diphenols used in the polymerization. The polycarbonate (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. In addition, the polycarbonate resin (A) may be used in part or in whole by an aromatic polyester-carbonate resin obtained by polymerizing in the presence of an ester precursor, such as a bifunctional carboxylic acid.

Polycarbonate resin (A) is used in the range of 45-95 weight part.

(B) rubber modified styrene graft copolymer resin

Rubber-modified graft copolymer resin used in the present invention is 50 to 95 parts by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, or a mixture thereof and acrylonitrile, methacrylonitrile, C _1-8 meta 5 to 95 parts by weight of a mixture of 5 to 50 parts by weight of alkyl acrylates, C _1-8 methacrylic acid esters, maleic anhydride, C _1-4 alkyl or phenyl N-substituted maleimide, or mixtures thereof Rubber, acrylic rubber, ethylene / propylene rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, isoprene rubber, ethylene-propylene-diene terpolymer (EPDM), and polyorganosiloxane / polyalkyl (meth) acrylate rubber It is a copolymer grafted to 5 to 95 weight part of one or a mixture of these selected from the group which consists of composites.

The C _1-8 methacrylic acid alkyl esters or C _1-8 acrylic acid alkyl esters are monohydryl alcohols each containing 1 to 8 carbon atoms as esters of acrylic acid or methacrylic acid. Preferred examples include methacrylic acid methyl ester, methacrylic acid ethyl ester or methacrylic acid propyl ester, of which methacrylic acid methyl ester is most preferred.

The rubber-modified styrenic graft copolymer resin can be prepared by a conventional polymerization method, but is most preferably synthesized by emulsion polymerization and bulk polymerization.

Preferred examples of the rubber-modified styrene-based graft copolymers include those obtained by graft copolymerization of styrene, acrylonitrile and optionally (meth) acrylic acid alkyl ester monomers in the form of a mixture of butadiene rubber, acrylic rubber, or styrene / butadiene rubber. Most preferred is an acrylonitrile / butadiene / styrene (ABS) graft copolymer in which acrylonitrile and styrene are grafted to butadiene rubber.

The rubber-modified styrenic graft copolymer resin is used in the range of 1 to 50 parts by weight of the entire base resin. The average size of the rubber particles used in preparing the graft copolymer is suitably in the range of 0.05 to 4 μm in consideration of impact strength and appearance.

(C) Styrene Copolymer Resin

Styrene-based copolymers used in the present invention is 50 to 95 parts by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene or a mixture thereof and acrylonitrile, methacrylonitrile, C _1-8 methacrylic acid alkyl ester Styrene copolymers obtained by copolymerizing 5 to 50 parts by weight of C _1-8 methacrylic acid esters, maleic anhydride, C _1-4 alkyl or phenyl N-substituted maleimide, or mixtures thereof. . This styrene copolymer resin is used in 0.5-50 weight part.

The C _1-8 methacrylic acid alkyl esters or C _1-8 acrylic acid alkyl esters are monohydryl alcohols having 1 to 8 carbon atoms as esters of acrylic acid or methacrylic acid, respectively. Preferred examples include methacrylic acid methyl ester, methacrylic acid ethyl ester or methacrylic acid propyl ester, and most preferably methacrylic acid methyl ester.

Styrene-based copolymers may be produced as by-products in the preparation of the rubber-modified styrene-based graft copolymers (B), especially when the excess monomer is grafted to a small amount of rubbery polymer. The content of the styrenic copolymer (C) used in the preparation of the resin composition of the present invention is not shown including the by-products produced during the preparation of the rubber-modified styrenic graft copolymer (B). That is, the styrene-based copolymer (C) used in the production of the resin composition of the present invention is a thermoplastic resin and does not contain a rubbery polymer.

Preferred embodiments of the styrene copolymer resin (C) include monomer mixtures of styrene and acrylonitrile and optionally methacrylic acid methyl ester, monomer mixtures of α-methylstyrene and acrylonitrile and optionally methacrylic acid methyl ester or Styrene, α-methylstyrene and acrylonitrile and optionally prepared from a monomer mixture of methacrylic acid methyl ester. The styrene / acrylonitrile copolymer may be prepared by emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization, and it is preferable to use a weight average molecular weight (M _w ) of 15,000 to 200,000.

The styrene monomer used in the preparation of the styrenic copolymer (C) of the present invention may be used in place of other substituted styrene monomers such as p-methylstyrene, vinyltoluene, 2,4-dimethylstyrene and α-methylstyrene. have.

The styrenic copolymers (C) described above can also be used alone or in mixture of two or more thereof.

(D) amine group-containing styrene copolymer resin

The amine group-containing styrene copolymer resins used as compatibilizers in the present invention include styrene, α-methylstyrene, halogen or methyl ring-substituted styrenes, C _1-8 methacrylic acid alkyl esters, C _1-8 methacrylic acid esters. 50 to 95 parts by weight of the same or mixtures thereof and 5 to 50 parts by weight of acrylonitrile, methacrylonitrile or a mixture thereof are prepared by copolymerization by adding 0.01 to 1.0 parts by weight of an amine group-containing free radical initiator and containing an amine group. Styrene-based copolymer resin is used in the range of 0.5 to 30 parts by weight.

The amine group-containing styrene copolymer resin is excellent in compatibility with the rubber-modified styrene graft copolymer which is itself a component (B) and the styrene copolymer that is a component (C). In addition, by reacting with the polycarbonate resin through the amine group to form a block copolymer is to act to improve the compatibility of the resin composition.

As the amine group-containing free radical initiator, all of a peroxide or an azo compound may be used, and any of those containing a primary amine or a secondary amine group may be used. Specific examples of the amine group-containing free radical initiators include 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2- (5-methyl-2 -Imidazolin-2-yl) propane], 2,2'-azobis (2-amidinopropane), and the like. The amine group-containing free radical initiator is preferably used in an amount of 0.01 to 1.0 parts by weight based on the amount of monomers to control the molecular weight of the styrene copolymer resin.

As the method for preparing the compatibilizer, any of emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization may be used, and a weight average molecular weight of 20,000 to 300,000 is preferably used.

In addition, the thermoplastic resin composition of the present invention may include general additives such as flame retardants, lubricants, mold release agents, fillers, nucleating agents, antistatic agents, stabilizers, plasticizers, reinforcing agents, inorganic additives, pigments, or dyes, depending on the respective uses, The inorganic additive is used in an amount of 0 to 60 parts by weight based on 100 parts by weight of the base resin component (A) + (B) + (C), and preferably in the range of 10 to 40 parts by weight. The resin composition of this invention can be manufactured by a conventional method. For example, the components of the present invention and other additives may be mixed simultaneously, then melt extruded in an extruder and prepared in pellet form.

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

Example

(A) polycarbonate resin, (B) rubber modified styrene graft copolymer resin, (C) styrene copolymer resin and (D) amine group-containing styrene copolymer used in the following Examples and Comparative Examples The specification of resin is as follows.

(A) polycarbonate resin

A polycarbonate of bisphenol-A type having a weight average molecular weight (Mw) of 22,000 was used.

(B) rubber modified styrene graft copolymer resin

Butadiene rubber latex was added so that the butadiene content was 45 parts by weight based on the total amount of the monomer, 1.0 parts by weight of potassium oleate, cumene hydroperoxide, which was an additive necessary for a mixture of 36 parts by weight of styrene, 14 parts by weight of acrylonitrile, and 150 parts by weight of deionized water. 0.4 parts by weight, 0.3 parts by weight of mercaptan-based chain transfer agent was added to the reaction while maintaining at 75 ℃ for 5 hours to prepare an ABS graft latex. A 1% sulfuric acid solution was added to the resulting polymer latex, solidified and dried to prepare a graft copolymer resin in a powder state.

(C) Styrene Copolymer Resin

A SAN copolymer resin was prepared by suspension polymerization by adding 0.2 parts by weight of azobisisobutyronitrile and 0.5 parts by weight of tricalcium phosphate, which are necessary additives to a mixture of 70 parts by weight of styrene, 30 parts by weight of acrylonitrile, and 120 parts by weight of deionized water. . The copolymer was washed with water, dehydrated and dried to obtain a SAN copolymer resin in powder form.

(D) amine group-containing styrene copolymer resin

Into a mixture of 71 parts by weight of styrene, 29 parts by weight of acrylonitrile, 20 parts by weight of ethanol and 130 parts by weight of benzene, 0.05 parts by weight of 2,2'-azobis [2- (2-imidazolin-2-yl) propane] was added. The solution was polymerized in a nitrogen atmosphere, and the copolymer was precipitated in n-hexane and dried to prepare a amine group-containing styrene copolymer resin in powder form.

Table 1 shows the composition and measured physical properties of each component used in Examples 1 to 3 and Comparative Examples. Examples 1-3 used amine group containing styrene copolymer resin which is a compatibilizer, and a comparative example is a case where a compatibilizer is not used.

As shown in Table 1, each component was mixed, antioxidant and heat stabilizer were added, mixed in a conventional mixer, extruded using a twin screw extruder having L / D = 35 and Φ = 45 mm, and then the extrudate was Prepared in pellet form.

Specimens for measuring the general physical properties were prepared using a 10 oz injection machine under the usual molding conditions at an injection temperature of 250 ℃. These specimens were measured for 40 hours at 23 ° C and 50% relative humidity, and then measured for physical properties according to ASTM standards.

Specimens for measuring physical properties during high temperature injection were prepared using a 10 oz injection machine with a cooling time of 5 minutes at an injection temperature of 300 ° C. It was.

division Example 1 Example 2 Example 3 Comparative Example ingredient (A) polycarbonate resin 60 60 60 60 (B) Styrene Graft Copolymer 15 15 15 15 (C) Styrene Copolymer 20 15 10 25 (D) amine group-containing styrene copolymer 5 10 15 - Properties Izod Notch Impact Strength (23 ℃) (1/8 ″, kgcm / cm) 59 58 58 61 Hot Injection Notch Impact Strength (23 ℃) (1/8 ″, kgcm / cm) 55 55 54 30 Izod Notch Impact Strength (-30 ℃) (1/8 ″, kgcm / cm) 40 39 37 40 Hot Injection Notch Impact Strength (-30 ℃) (1/8 ″, kgcm / cm) 35 35 34 15

The Izod impact strength is evaluated by ASTM D256.

As shown in Examples and Comparative Examples of Table 1, when the amine group-containing styrene copolymer resin is used as a compatibilizer, the notch impact strength (23 ° C) of the specimen injected at high temperature (300 ° C) is a general injection condition. Almost no decrease in the impact strength of the specimen injected at, but it can be seen that the notch impact strength of the specimen injected at a high temperature is sharply reduced unless the amine group-containing styrene copolymer resin is used. In addition, when the amine group-containing styrene copolymer resin is used, it can be seen that the low temperature (-30 ° C.) impact strength of the high-temperature injected specimen is also maintained without being lowered.

The present invention uses an amine group-containing styrene copolymer resin obtained by copolymerizing styrene-based and acrylonitrile-based monomers with an amine group-containing free radical initiator as a compatibilizer, thereby increasing the impact strength of the molding at high temperature injection. The mechanical properties such as low temperature impact resistance, thermal stability, heat resistance, workability, weld-line strength and appearance are excellent without any deterioration of mechanical properties such as It has the effect of providing a thermoplastic resin composition useful for producing an injection molding of a device.

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)

(A) 45-95 parts by weight of polycarbonate resin; (B) 50 to 95 parts by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene or mixtures thereof, acrylonitrile, methacrylonitrile, C _1-8 methacrylic acid alkyl esters, C _1-8 meta 5 to 95 parts by weight of a mixture of 5 to 50 parts by weight of krylic acid esters, maleic anhydride, C _1-4 alkyl or phenyl N-substituted maleimide or mixtures thereof, butadiene rubber, acrylic rubber, ethylene / propylene rubber, styrene / Polymers selected from butadiene rubber, acrylonitrile / butadiene rubber, isoprene rubber, terpolymer (EPDM) of ethylene-propylene-diene, polyorganosiloxane / polyalkyl (meth) acrylate rubber composites or mixtures thereof 1 to 50 parts by weight of rubber-modified graft copolymer resin grafted in 95 parts by weight; (C) 50 to 95 parts by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene or mixtures thereof, acrylonitrile, methacrylonitrile, C _1-8 methacrylic acid alkyl esters, C _1-8 meta 0.5 to 50 parts by weight of a styrenic copolymer obtained by copolymerizing 5 to 50 parts by weight of acrylic acid esters, maleic anhydride, C _1-4 alkyl or phenyl N-substituted maleimide or a mixture thereof; And (D) 50 to 95 parts by weight of styrene, α-methylstyrene, halogen or methyl ring-substituted styrene, C _1-8 methacrylic acid, alkyl esters, C _1-8 methacrylic acid esters or mixtures thereof and acryl 0.5 to 30 parts by weight of an amine group-containing styrene copolymer resin prepared by adding 0.01 to 1.0 parts by weight of an amine group-containing free radical initiator to 5 to 50 parts by weight of ronitrile, methacrylonitrile or a mixture thereof; Thermoplastic resin composition, characterized in that consisting of. The method of claim 1, wherein the amine group-containing free radical initiator is 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2- (5 -Methyl-2-imidazolin-2-yl) propane], 2,2'-azobis (2-amidinopropane). The thermoplastic resin composition of claim 1, wherein the resin composition further comprises a flame retardant, a lubricant, a mold releasing agent, a filler, a nucleating agent, an antistatic agent, a stabilizer, a plasticizer, a reinforcing material, an inorganic additive, a pigment, or a dye. Molded article prepared from the thermoplastic resin composition of claim 1.