KR100372568B1 - Thermoplastic Resin Composition - Google Patents

Abstract

The thermoplastic resin composition according to the present invention comprises (A) 45-95 parts by weight of a thermoplastic polycarbonate resin; (B) (b ₁ ) 50-95% by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, or mixtures thereof with acrylonitrile, methacrylonitrile, maleic anhydride, C ₁ -C ₄ alkyl or 5-95 parts by weight of a monomer mixture consisting of phenyl N-substituted maleimide or a mixture of 50-5% by weight of (b ₂ ) butadiene rubber, acrylic rubber, ethylene / propylene rubber, styrene / butadiene rubber, acrylonitrile / 95-5 parts by weight of one or two or more blends selected from the group consisting of butadiene rubber, isoprene rubber, ethylene / propylene / diene terpolymer (EPDM) and polyorganosiloxane / polyalkyl (meth) acrylate rubber composites 1-50 parts by weight of the rubber-modified styrene graft copolymer obtained by graft polymerization; (C) (c ₁ ) 50-95% by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, or mixtures thereof and (c ₂ ) acrylonitrile, methacrylonitrile, maleic anhydride, C ₁ -C ₄ alkyl or phenyl, N- substituted maleimides, or 0.5-50 parts by weight of a styrenic copolymer consisting of a mixture of 50-5% by weight thereof; And (D) (d ₁ ) 55-90 wt% of a C ₁ -C ₈ methacrylic acid alkyl ester, a C ₁ -C ₈ acrylic acid alkyl ester, or mixtures thereof, (d ₂ ) styrene, α-methylstyrene, halogen Or methacrylic acid or acrylic ester copolymer 0.5 consisting of 5-55% by weight of alkyl substituted styrene, or mixtures thereof, and (d ₃ ) 1-20% by weight of acrylonitrile, methacrylonitrile, or mixtures thereof. It consists of -50 parts by weight.

Description

Thermoplastic Resin Composition

Field of invention

The present invention relates to a thermoplastic resin composition having excellent mechanical properties. More specifically, in the present invention, by using a (meth) acrylic acid ester copolymer as a compatibilizer, the mechanical properties of the molded product are not deteriorated during high-temperature injection, and low-temperature impact resistance, thermal stability, weld-line strength and heat resistance The present invention relates to a thermoplastic resin composition having excellent workability and appearance characteristics.

Background of the Invention

Polycarbonate resins are excellent in transparency, mechanical strength and heat resistance, and are widely used in applications such as electric, electronic products, and automobile parts. However, since polycarbonate resins have disadvantages of poor workability and notched impact strength, they are blended with other types of resins to improve them. For example, a blend of a polycarbonate resin and a rubber-modified styrene copolymer improves workability while maintaining high notch impact strength. However, such blends of polycarbonate / styrene copolymers have a phenomenon in which the domain size of components forming a dispersed phase becomes large when the blend is held at a high temperature during an extrusion or injection process. 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 in this way, the mechanical properties of the molding rapidly decrease.

U. S. Patent No. 5,292, 786 discloses a resin composition composed of polycarbonate resin, ABS resin, phosphorus flame retardant and polyalkyl methacrylate resin, with improved weld line strength. However, 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.

US Pat. Nos. 5,373,065 and 5,552,480 disclose that a method of preparing a copolymer resin by introducing an amine group into a styrene or olefin resin and the compatibility of the thermoplastic resin composition produced by the method are improved. 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 with a polycarbonate resin and a vinyl polymer. However, even in the above method, the amine group is introduced to the already prepared resin through a method such as extrusion. However, the procedure is complicated and the process conditions are difficult, and there are many limitations for commercial use.

The present inventors apply a (meth) acrylic acid ester copolymer as a compatibilizer to a thermoplastic resin composition composed of a polycarbonate resin, a rubber modified styrene graft copolymer and a styrene copolymer in order to solve the above conventional problems. By doing so, it is possible to produce a thermoplastic resin composition having excellent balance of physical properties such as low temperature impact resistance, thermal stability, joint strength, heat resistance, workability and appearance, without deteriorating mechanical properties during high temperature injection.

An object of the present invention is to apply a (meth) acrylic acid ester copolymer as a compatibilizer to a resin composition comprising a polycarbonate resin, a rubber-modified styrene graft copolymer and a styrene copolymer, so that the mechanical properties of the molding at high temperature injection It is to provide a thermoplastic resin composition which does not exhibit a deterioration.

Another object of the present invention is to provide a thermoplastic resin composition having excellent compatibility at low temperature impact resistance, thermal stability and weld line strength by increasing the compatibility by using a (meth) acrylic acid ester copolymer as a compatibilizer.

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.

The thermoplastic resin composition of the present invention

(A) 45-95 parts by weight of a thermoplastic polycarbonate resin;

(B) (b ₁ ) 50-95% by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, or mixtures thereof and acrylonitrile, methacrylonitrile, maleic anhydride, C ₁ -C ₄ alkyl or 5-95 parts by weight of a monomer mixture consisting of phenyl N-substituted maleimide or a mixture of 50-5% by weight of (b ₂ ) butadiene rubber, acrylic rubber, ethylene / propylene rubber, styrene / butadiene rubber, acrylonitrile / 95-5 parts by weight of one or two or more blends selected from the group consisting of butadiene rubber, isoprene rubber, ethylene / propylene / diene terpolymer (EPDM) and polyorganosiloxane / polyalkyl (meth) acrylate rubber composites 1-50 parts by weight of the rubber-modified styrene graft copolymer obtained by graft polymerization;

(C) (c ₁ ) 50-95% by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, or mixtures thereof and (c ₂ ) acrylonitrile, methacrylonitrile, maleic anhydride, C ₁ -C ₄ alkyl or phenyl, N- substituted maleimides, or 0.5-50 parts by weight of a styrenic copolymer consisting of a mixture of 50-5% by weight thereof; And

(D) (d ₁ ) 55-90% by weight of C ₁ -C ₈ methacrylic acid alkyl esters, C ₁ -C ₈ acrylic acid alkyl esters, or mixtures thereof, (d ₂ ) styrene, α-methylstyrene, halogen or Methacrylic acid or acrylic ester copolymer 0.5-50 consisting of 5-55% by weight of alkyl-substituted styrene, or mixtures thereof, and (d ₃ ) 1-20% by weight of acrylonitrile, methacrylonitrile, or mixtures thereof. It consists of parts by weight.

Hereinafter, (A) polycarbonate resin, (B) rubber modified styrene graft copolymer, (C) styrene copolymer and (D) methacrylic acid or acrylic ester which are each component of the thermoplastic resin composition of this invention A copolymer is demonstrated in detail.

(A) polycarbonate resin

The aromatic polycarbonate resin, which is the component (A) used in the preparation of the resin composition of the present invention, may be prepared by reacting diphenols represented by the following structural formula (1) with phosgene, halogen formate or diester carbonate. :

Structural Formula 1

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

Specific examples of the diphenol include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis- (4-hydroxyphenyl) -propane, 2,4-bis- (4-hydroxy Phenyl) -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- Hydroxyphenyl) -cyclohexane and the like are preferable. More preferably, 2,2-bis- (4-hydroxyphenyl) -propane is most commonly used industrially and is called bisphenol-A.

Suitable polycarbonates (A) for use in the preparation of the resin compositions of the invention have a weight average molecular weight of 10,000-200,000, preferably 15,000-80,000.

The polycarbonate resin may be branched chain, preferably 0.05 to 2 mol% of tri- or more polyfunctional compounds, such as trivalent or more phenol groups, based on the total amount of diphenols used for polymerization. It can be prepared by adding a compound having. The polycarbonate may also be used in the form of a homo polycarbonate, co polycarbonate, or mixtures thereof.

The polycarbonate resin used in the production of the resin composition of the present invention may be partially or entirely replaced by an aromatic polyester-carbonate resin obtained by polymerizing in the presence of an ester precursor, such as a bifunctional carboxylic acid.

(B) Rubber Modified Styrene Graft Copolymer

The rubber-modified styrenic graft copolymer (B) used in the present invention is 5-95 parts by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, or a mixture thereof 50-95% by weight of acrylonitrile, 95-5 parts by weight of butadiene rubber, acrylic monomer mixture (b ₁ ) consisting of 50-5% by weight of methacrylonitrile, maleic anhydride, C ₁ -C ₄ alkyl or phenyl N-substituted maleimide, or mixtures thereof Group consisting of rubber, ethylene / propylene rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, isoprene rubber, ethylene / propylene / diene terpolymer (EPDM) and polyorganosiloxane / polyalkyl (meth) acrylate rubber composite It is prepared by grafting on one or two or more blends (b ₂ ) selected from.

Preferred examples of the rubber-modified styrene graft copolymer (B) include graft copolymers of butadiene rubber, acrylic rubber, or styrene / butadiene rubber in the form of a mixture of monomers of styrene and acrylonitrile. Most preferred are ABS (acrylonitrile / butadiene / styrene) graft copolymers.

The particle diameter of the rubber (b ₂ ) used above is preferably used in the range of 0.05 to 4 ㎛ in order to improve the impact strength and the surface properties of the molded product.

The method for preparing the graft copolymer is well known to those skilled in the art, and any of emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization may be used. Preferably, the aromatic vinyl monomer is introduced in the presence of a rubbery polymer, followed by emulsion polymerization or bulk polymerization using a polymerization initiator.

(C) Styrene Copolymer

The styrenic copolymer (C) used in the resin composition of the present invention is 50-95% by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, or mixtures thereof (c ₁ ) and 50-5% by weight of Prepared by copolymerizing acrylonitrile, methacrylonitrile, maleic anhydride, C ₁ -C ₄ alkyl or phenyl N-substituted maleimide, or mixtures thereof (c ₂ ).

The styrene-based copolymer (C) may be produced as a by-product in the preparation of the rubber-modified graft copolymer (B), and particularly in the case of grafting an excess monomer mixture to a small amount of rubbery polymer or as a molecular weight regulator. It is more likely to occur in the case of using an excessive amount of the chain transfer agent used. Herein, the content of the styrene copolymer (C) used in the preparation of the resin composition of the present invention does not include the by-product of the graft copolymer (B). In addition, the styrene copolymer (C) is a thermoplastic resin and does not include a rubbery polymer.

Preferred styrenic copolymers (C) include monomer mixtures of styrene and acrylonitrile; monomer mixtures of α-methylstyrene and acrylonitrile; Or copolymers made from styrene and a monomer mixture of α-methylstyrene and acrylonitrile. The styrene copolymer (C) may be prepared by emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization, and it is preferable to use a weight average molecular weight of 15,000-200,000.

The styrene monomer (c ₁ ) used in the preparation of the styrene-based copolymer (C) is, in addition to the monomers described above, other substituted styrenes such as p-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, or α-methylstyrene. It can be used instead of the monomer.

The styrenic copolymer (C) used in the preparation of the resin composition of the present invention described above may be used alone or in the form of a mixture of two or more thereof.

(D) (meth) acrylic acid ester copolymer

The (meth) acrylic acid ester copolymer (D) used in the preparation of the resin composition of the present invention may be a C ₁ -C ₈ methacrylic acid alkyl ester, a C ₁ -C ₈ acrylic acid alkyl ester, or a mixture thereof (d ₁ ). 55-90 wt%, styrene, α-methylstyrene, halogen or alkyl substituted styrene, or mixtures thereof (d ₂ ) 5-55 wt% and acrylonitrile, methacrylonitrile, or mixtures thereof (d ₃ ) 1-20% by weight.

The C ₁ -C ₈ methacrylic acid alkyl ester or C ₁ -C ₈ acrylic acid alkyl ester is esters obtained from methacrylic acid or acrylic acid and monohydryl alcohol containing 1 to 8 carbon atoms, respectively. Specific examples thereof include methacrylic acid methyl ester, methacrylic acid ethyl ester, acrylic acid ethyl ester, or methacrylic acid propyl ester, of which methacrylic acid methyl ester is most preferred.

The (meth) acrylic acid ester copolymer (D) is used as a compatibilizer in the resin composition of the present invention, and includes a polycarbonate resin (A), a rubber-modified styrene graft copolymer (B), and a base resin. The compatibility with each of the styrene copolymer (C) is excellent, thereby improving the compatibility of the thermoplastic resin composition of the present invention.

The (meth) acrylic acid ester copolymer (D) may be any of emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization, and a weight average molecular weight of 20,000-300,000 is preferably used.

The (meth) acrylic acid ester copolymer (D) used in the preparation of the resin composition of the present invention is added in the range of 0.5-50 parts by weight, and preferably used in the range of 1-40 parts by weight.

In addition to the above components, the thermoplastic resin composition of the present invention may further include general additives such as flame retardants, lubricants, mold release agents, nucleating agents, antistatic agents, stabilizers, reinforcing materials, inorganic additives, pigments, or dyes. The added additives may be used in the range of 0 to 60 parts by weight, preferably 1 to 40 parts by weight based on 100 parts by weight of the base resin component (A) + (B) + (C).

The resin composition of the present invention can be produced by a known method for producing a resin composition. 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 composition of the present invention can be used for molding a variety of products, and is particularly suitable for the manufacture of housings of electrical and electronic products, such as computer housings that require high low temperature impact resistance while being injected at high temperatures (300 ° C.).

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 styrenic graft copolymer, (C) styrene copolymer resin, (D) methacrylic acid or acrylic acid used in the resin compositions of Examples and Comparative Examples of the present invention. Specifications of the ester copolymer and (E) polymethyl methacrylate are as follows:

(A) polycarbonate resin

As the polycarbonate resin, a polycarbonate resin prepared from bisphenol-A having a weight average molecular weight (Mw) of 25,000 was used.

(B) Rubber Modified Styrene Graft Copolymer

Butadiene rubber latex was added so that the butadiene content was 45 parts by weight based on the total amount of the monomers, 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 rubber-modified styrenic graft copolymer resin in a powder state. The graft copolymer resin prepared by the above method was used as the rubber-modified styrenic graft copolymer.

(C) Styrene Copolymer Resin

Add 0.2 parts by weight of azobisisobutyronitrile, 0.3 part by weight of mercaptan-based chain transfer agent, and 0.5 part by weight of tricalcium phosphate, which are necessary additives for the mixture of 71 parts by weight of styrene, 29 parts by weight of acrylonitrile and 120 parts by weight of deionized water. The polymerization was performed to prepare a SAN copolymer resin. This SAN copolymer was washed with water, dehydrated and dried to obtain a powdery SAN copolymer resin. As the styrene copolymer resin, a SAN copolymer prepared by the above method was used.

(D) (meth) acrylic acid ester copolymer

0.2 part by weight of azobisisobutyronitrile as a polymerization initiator in a mixture of 70 parts by weight of methacrylic acid methyl ester, 20 parts by weight of styrene and 10 parts by weight of acrylonitrile, and 120 parts by weight of deionized water, and 0.3 parts by weight of mercaptan-based chain transfer agent. And 0.5 parts by weight of tricalcium phosphate was added and suspended polymerization to prepare a methacrylic acid methyl ester copolymer resin. The copolymer was washed with water, dehydrated and dried to obtain a resin in powder form. As methacrylic acid (or acrylic acid) ester copolymer resin, methacrylic acid methyl ester copolymer resin prepared by the above method was used.

(E) polymethyl methacrylate

Polymethyl methacrylate used in the comparative example of the present invention used IH-830 of LG Chem.

Example 1-4

Each component of the composition shown in Table 1, antioxidant and heat stabilizer were added, mixed in a conventional mixer, extruded at a temperature of 250 ° C. using a twin screw extruder having L / D = 35 and Φ = 45 mm, and then extruded. Water was prepared in pellet form.

(Unit: weight part) Example Comparative Example One 2 3 4 One 2 (A) polycarbonate resin 60 60 60 60 60 60 (B) Rubber modified styrene graft copolymer 15 15 15 15 15 15 (C) Styrene Copolymer 20 15 10 5 25 10 (D) methacrylic acid ester copolymer 5 10 15 20 - - (E) Polymethyl methacrylate - - - - - 15

In order to measure the thermal stability of the resin composition prepared by the above method, the decomposition start temperature was measured by observing the mass loss of the composition while raising the specimen at a rate of 20 ° C./min in a nitrogen atmosphere. In addition, the reduction in mass was measured by staying at a temperature of 300 ° C. for 30 minutes.

Specimens for measuring seam strength and Izod impact strength were prepared using a 10 oz injection machine under normal molding conditions at an injection temperature of 260 ° C. These specimens were measured for 40 hours at 23 ° C. and 50% relative humidity, and then measured for physical properties according to ASTM D256.

Specimens for measuring physical properties during high temperature injection were manufactured using a 10 oz injection machine with a cooling time of 5 minutes at an injection temperature of 300 ° C. The measurement conditions for physical properties were the same as those for the measurement of general properties. It was done. Table 2 shows the results of measuring the respective physical properties.

Comparative Example 1-2

As described in Table 1, except that the composition of each component was changed, the specimens were prepared in the same manner as in Example 1-4, and the physical properties of each were measured and the results are shown in Table 2.

Example Comparative Example One 2 3 4 One 2 Decomposition start temperature (℃) 410 405 399 394 416 380 Mass loss (%) (300 ℃, after 30 min stay) 1.4 1.4 1.5 1.6 1.4 1.9 Bond line impact strength (2) (23 ° C) (1/8 ", kgcm / cm) 21 26 28 29 12 22 Izod notch impact strength (2) (23 ° C) (1/8 ", kgcm / cm) 72 69 63 61 70 58 Hot Injection Notch Impact Strength (23 ℃) (1/8 ", kgcm / cm) 57 56 55 55 35 45 Hot Injection Notch Impact Strength (-30 ℃) (1/8 ", kgcm / cm) 41 40 40 38 15 25

From the results in Table 2, it was found that when the (meth) acrylic acid ester copolymer (D) of the present invention was used as a compatibilizer, the bond line impact strength was very excellent as compared with the case where it was not used. The notch impact strength (23 ° C) of the specimen injected at high temperature (300 ° C) while using the compatibilizer is hardly reduced compared to the impact strength of the specimen injected under the general injection conditions, but the methacrylic acid or acrylic ester-based air The notch impact strength of the specimen injected at high temperature (300 ° C.) without using the copolymer as a compatibilizer is rapidly decreased. In addition, when the compatibilizer is used, the low temperature (-30 ° C.) impact strength of the high-temperature injected specimen is also maintained without a significant decrease.

On the other hand, in the case of using polymethyl methacrylate as shown in Comparative Example 2, the bond line strength is excellent, but the impact strength of the high-temperature injection test specimen does not reach the value of the example, and the thermal stability of the resin is lower than 400 ° C. as the start temperature of decomposition. This is very low.

The thermoplastic resin composition of the present invention is applied to a resin composition comprising a polycarbonate resin, a rubber-modified styrene graft copolymer and a styrene copolymer, by applying a (meth) acrylic acid ester copolymer as a compatibilizer, thereby increasing compatibility and high temperature. It has excellent balance of physical properties such as low temperature impact resistance, thermal stability, joint strength, heat resistance, workability and appearance, without deterioration of mechanical properties such as impact strength of moldings during injection. Has the effect of the invention useful for producing injection molding of the 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 a thermoplastic polycarbonate resin; (B) (b ₁ ) 50-95% by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, or mixtures thereof and acrylonitrile, methacrylonitrile, maleic anhydride, C ₁ -C ₄ alkyl or 5-95 parts by weight of a monomer mixture consisting of phenyl N-substituted maleimide or a mixture of 50-5% by weight of (b ₂ ) butadiene rubber, acrylic rubber, ethylene / propylene rubber, styrene / butadiene rubber, acrylonitrile / 95-5 parts by weight of one or two or more blends selected from the group consisting of butadiene rubber, isoprene rubber, ethylene / propylene / diene terpolymer (EPDM) and polyorganosiloxane / polyalkyl (meth) acrylate rubber composites 1-50 parts by weight of the rubber-modified styrene graft copolymer obtained by graft polymerization; (C) (c ₁ ) 50-95% by weight of styrene, α-methylstyrene, halogen or alkyl substituted styrene, or mixtures thereof and (c ₂ ) acrylonitrile, methacrylonitrile, maleic anhydride, C ₁ -C ₄ alkyl or phenyl, N- substituted maleimides, or 0.5-50 parts by weight of a styrenic copolymer consisting of a mixture of 50-5% by weight thereof; And (D) (d ₁ ) 55-90% by weight of C ₁ -C ₈ methacrylic acid alkyl esters, C ₁ -C ₈ acrylic acid alkyl esters, or mixtures thereof, (d ₂ ) styrene, α-methylstyrene, halogen or Methacrylic acid or acrylic ester copolymer 0.5-50 consisting of 5-55% by weight of alkyl-substituted styrene, or mixtures thereof, and (d ₃ ) 1-20% by weight of acrylonitrile, methacrylonitrile, or mixtures thereof. Parts by weight; Thermoplastic resin composition, characterized in that consisting of. The C ₁ -C ₈ methacrylic acid alkyl ester or C ₁ -C ₈ acrylic acid alkyl ester in the (meth) acrylic acid ester copolymer (D) is a methacrylic acid methyl ester or ethyl methacrylate. A thermoplastic resin composition, characterized in that the ester, acrylic acid ethyl ester, or methacrylic acid propyl ester. According to claim 1, wherein the resin composition is flame retardant, lubricant, mold release agent, nucleating agent, antistatic agent, stabilizer, reinforcing material, inorganic additives, pigments or dyes based resin composition (A) + (B) + (C) 100 parts by weight Excellent thermoplastic resin composition, characterized in that it further comprises in the range of 0 to 60 parts by weight relative to. A molded article manufactured using the thermoplastic resin composition according to any one of claims 1 to 3.