KR100360714B1 - Flame retardant thermoplastic resin composition based on polycarbonate - Google Patents

Abstract

PURPOSE: A flame retardant thermoplastic resin composition based on polycarbonate is provided to prevent the generation of stress crack and the generation of liquid impurities by the volatilization of the flame retardant. CONSTITUTION: The flame retardant thermoplastic resin composition comprises: (A) 50 to 95 wt% of a thermoplastic polycarbonate resin containing no halogens; (B) 5 to 50 wt% of a rubber-modified and styrene-containing graft copolymer resin which contains no halogens; (C) 0 to 30 wt% of a styrene-containing copolymer resin which contains no halogens; (D) an alkylated triphenylphosphate consisting of 1 to 20 wt% of a trialkyl phenyl phosphate, 10 to 50 wt% of a dialkyl phenyl monophenyl phosphate, 15 to 60 wt% of a monoalkyl phenyl diphenyl phosphate and less than 2 wt% of triphenyl phosphate; and (E) a fluorinated polyolefin resin, wherein (D) and (E) are used in the amount of 3 to 20 wt% and 0 to 2 wt%, respectively, based on 100 wt% of (A)+(B)+(C).

Description

Polycarbonate-based thermoplastic resin composition having flame retardancy

Field of invention

The present invention relates to a polycarbonate-based thermoplastic resin composition having flame retardancy. More specifically, the present invention relates to a polycarbonate-based thermoplastic resin composition comprising a polycarbonate resin, a rubber modified styrene-containing graft copolymer, a styrene-containing copolymer, an alkylated triphenyl phosphate, and a fluorinated polyolefin-based resin.

Background of the Invention

Polycarbonate resins are excellent in transparency, mechanical strength and heat resistance and are used in many applications such as electric and electronic products and automobile parts. However, polycarbonate resins themselves have disadvantages of low notch impact strength and poor workability. Therefore, in order to improve processability and notch impact strength, it is blended with other kinds of resins. For example, a mixture of polycarbonate resin and styrene resin is a resin mixture which maintains high notch impact strength and improves workability. Since the resin of this polycarbonate composition is usually applied to a large heat dissipating material such as a computer housing or other office equipment, it is essential that the resin should be flame retardant and maintain high mechanical strength.

Conventionally, halogen-based flame retardants have been used to impart flame retardancy to such resin compositions. However, when halogen-based flame retardants are used, the demand for resins containing no halogen-based flame retardants has been rapidly expanded due to the human hazards of gases generated during combustion. A technique for imparting flame retardancy without using a halogen-based flame retardant is currently the most common is to use a phosphate ester flame retardant.

However, the phosphate ester flame retardant has a problem of lowering the heat resistance, occurrence of stress cracks due to volatilization of the flame retardant during injection, and volatilized flame retardant on the surface of the molded article.

In order to solve this problem, Japanese Patent Publication No. 62-25706 used a mixture of aryl phosphate ester and phosphate ester oligomer obtained by reaction of phosphorus oxychloride, dihydric phenols and monohydric phenols as a flame retardant. However, the flame retardant prepared by this method has a metal ion derived from metal salts such as phosphorus oxychloride and aluminum chloride and magnesium chloride used as a catalyst, causing mold corrosion problems during molding.

US Pat. No. 5,061,745 also used polycarbonate resins, rubber modified styrene-containing graft copolymers, styrene-containing copolymers, triphenyl phosphate (TPP) and fluorinated polyolefin-based resins in phosphate ester flame retardants. The composition has a severe heat resistance deterioration due to the use of TPP and has a problem of working environment due to volatility of the flame retardant, mold contamination, and volatilized flame retardant on the surface of the molded article. For example, US Patent No. 5,204, 394 describes a resin composition using a phosphate ester oligomer having a degree of condensation of a specific range or more for a polycarbonate resin and a styrene resin as a flame retardant. However, in the case of using a flame retardant having an average value of 1.4 with respect to general formula (I), the flame retardancy is V-0, but when a flame retardant having an average value of n is 2.8, the flame retardancy becomes HB and the flame retardant performance is significantly reduced. Could know.

Wherein A _r ^{1 to} A _r ⁴ are aryl groups in which 1 to 3 phenyl groups or C _{1 to} C ₄ alkyl groups are substituted, R is a divalent aromatic group, and n is a degree of polymerization.

In this regard, the present inventors studied to improve the stress crack generation and the liquid substance generation by volatilization of phosphate ester flame retardant. As a result, polycarbonate resin, rubber modified styrene-containing graft copolymer, styrene-based copolymer, alkylated triphenyl When the resin composition was prepared using an appropriate ratio of phosphate and fluorinated polyolefin resin, it was found that a resin composition having much less stress crack generation and less liquid foreign matter generation than the phosphate ester oligomer alone was produced.

Purpose of the Invention

An object of the present invention is to provide a polycarbonate-based thermoplastic resin composition having a flame retardancy with little occurrence of stress cracks.

Another object of the present invention is to provide a thermoplastic resin composition having a flame retardancy capable of removing the manifestation of the volatilized flame retardant on the surface of the molded article.

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

Summary of the Invention

Polycarbonate-based thermoplastic resin composition of the present invention (A) 50 to 95% by weight of polycarbonate resin, (B) 5 to 50% by weight of rubber modified styrene-containing graft copolymer, (C) 0 to 30% by weight of styrene-containing copolymer %, (D) 3-20% by weight of alkylated triphenyl phosphate relative to 100% by weight of (A) + (B) + (C), and (E) (A) + (B) + (C) 100 It consists of 0-2 weight% of fluorinated polyolefin resin with respect to weight%.

The alkylated triphenylphosphate (D) may comprise 1-20% by weight of trialkylphenyl phosphate, 10-50% by weight of dialkylperyl monophenyl phosphate, 15-60% by weight of monoalkylphenyl diphenyl phosphate, and less than 2% by weight. As the composition consisting of triphenyl phosphate, the alkyl group to be substituted is preferably a t-butyl, isopropyl, isobutyl or isoamyl group.

In the resin composition of the present invention, inorganic additives, carbon fibers, heat stabilizers, light stabilizers, pigments, and / or dyes may be added according to respective uses.

Detailed Description of the Invention

The polycarbonate-based thermoplastic resin composition of the present invention comprises (A) a polycarbonate resin, (B) a rubber modified styrene-containing graft copolymer, (C) a styrene-containing copolymer, (D) an alkylated triphenyl phosphate, and (E) It consists of a fluorinated polyolefin resin, the detailed description of each of these components is as follows.

(A) polycarbonate resin

The polycarbonate resin (A) of the present invention is an aromatic polycarbonate which does not contain a halogen and is produced by the reaction of a divalent phenol compound with phosgene or diester carbonate. As the dihydric phenol compound, bisphenols are preferable, and 2,2'-bis (4-hydroxyphenyl) propane, that is, bisphenol A is more preferable. The structure of polycarbonate which is generally used is as shown in the following formula (II):

N is the degree of polymerization.

The polycarbonate resin (A) together with the rubber modified styrene-containing graft copolymer (B) and / or the styrene-containing copolymer constitutes a base resin. Polycarbonate is used in the range of 50 to 95 weight% among all the basic resins.

(B) Rubber Modified Styrene-Containing Graft Copolymer

Rubber-modified styrene-containing graft copolymer resin used in the present invention is at least one of styrene, alphamethyl styrene and nuclear substituted styrene 30 to 65% by weight, and at least one of acrylonitrile, methyl methacrylate and butyl acrylate Is a resin obtained by grafting a mixture of 10 to 30% by weight to 15 to 60% by weight of rubber. The graft copolymer resin may be prepared by a conventional polymerization method, but is preferably one synthesized by emulsion polymerization and bulk polymerization.

Acrylonitrile / butadiene / styrene (ABS) resins in which acrylonitrile and styrene are grafted to butadiene rubber are widely used. The rubber modified styrene-containing graft copolymer is used in the range of 5 to 50% by weight in the total base resin.

(C) styrene-containing copolymer

The styrenic-containing copolymer used in the present invention is 50 to 80% by weight of at least one of styrene, alpha-methylstyrene and nuclear substituted styrene, and at least one of acrylonitrile, methyl methacrylate and butyl acrylate 20 to 20 50 wt%. As the styrene-containing copolymer resin, one produced by a conventional polymerization method can be used, and one synthesized by suspension polymerization or bulk polymerization is particularly suitable.

(D) alkylated trickphenyl phosphate

The alkylated triphenylphosphate (D) used in the present invention comprises 1 to 20% by weight of trialkyl phenyl phosphate, 10 to 50% by weight of dialkylphenyl monophenyl phosphate, 15 to 60% by weight of monoalkylphenyl diphenyl phosphate, and As the composition consisting of less than 2% by weight of triphenyl phosphate, the alkyl group to be substituted is preferably a t-butyl, isopropyl, isobutyl or isoamyl group, more preferably t-butyl and isopropyl.

Alkylated triphenyl phosphate (D) for use in the present invention is disclosed in US Pat. No. 5,206,404. In the present invention, about 3 to 20% by weight of alkylated triphenyl phosphate (D) is used relative to 100% by weight of the base resin consisting of the above components (A) + (B) + (C).

(E) fluorinated polyolefin resin

Fluorinated polyolefin resins used in the present invention are conventionally available resins such as polytetrafluoroethylene, polyvinylidene fluoride, copolymers of tetrafluoroethylene and vinylidene fluoride, and tetrafluoroethylene and hexafluoro There is a copolymer of ropropylene. These may be used independently from each other, or a mixture of two or more different from each other may be used. The fluorinated polyolefin resin prevents the dropping of the resin by decreasing the flow viscosity and increasing the shrinkage rate of the resin during the combustion to form a fibrous net in the resin when mixed and extruded together to prevent the dropping during combustion. When the fluorinated polyolefin resin in an emulsion state is used, the dispersibility of the fluorinated polyolefin resin with respect to the entire resin is good, but there is a disadvantage in that the process is complicated. Therefore, even if it is a powder state, it can use preferably if it can form a fibrous net by disperse | distributing suitably to all resin. The fluorinated polyolefin resin which can be preferably used in the present invention is polytetrafluoroethylene. Polytetrafluoroethylene having a particle size of 20 to 500 microns is suitable for mixing. The amount of fluorinated polyolefin resin used is 0 to 2.0 wt% with respect to 100 wt% of the base resin.

The thermoplastic resin composition of the present invention is mixed in a conventional mixer after addition of inorganic additives, carbon fibers, heat stabilizers, antioxidants, light stabilizers, pigments and / or dyes according to the respective uses. This mixture is prepared into a resin composition in pellet form through an extruder. At this time, the inorganic additives added may include asbestos, glass fibers, talc and ceramics, which may be used in the range of 0 to 50 parts by weight based on 100 parts by weight of the base resin.

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 containing graft copolymer, (C) styrene containing copolymer, (D ₁ ) alkylated used in Examples 1 to 2 and Comparative Examples 1 to 4 below The specifications of the triphenyl phosphate, (D ₂ ) triphenyl phosphate (TPP), (D ₃ ) phosphate ester oligomer, and (E) fluorinated polyolefin resin are as follows.

(A) polycarbonate resin

Samyang Corporation 3020PJ GARDE was used.

(B) Rubber modified styrene-containing graft copolymer (g-ABS)

Butadiene rubber latex was added so that the butadiene content was 45 parts by weight based on the whole monomer, 1.0 parts by weight of potassium oleate, 1.0 parts by weight of quenehydroperoxide, an additive required for a mixture of 36 parts by weight of styrene, 14 parts by weight of acrylonitrile and 150 parts by weight of deionized water. Part, 0.3 parts by weight of mercaptan-based chain transfer agent was added and maintained at 75 ° C. for 5 hours to complete the reaction, thereby preparing g-ABS latex. The resulting polymer latex was added with 1% sulfuric acid solution and dried after coagulation to prepare a graft copolymer resin in powder form.

(C) Styrene-containing copolymer resin (SAN)

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 for 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 ₁ ) alkylated triphenylphosphate

As alkylated triphenylphosphate, 12.5 wt% tri (t-butylphenyl) phosphate, 49.5 wt% di (t-butylphenyl) phenyl phosphate, 33.2 wt% diphenyl t-butylphenyl phosphate, and 0.5 wt% triphenyl phosphate A mixture consisting of was used.

(D ₂ ) triphenyl phosphate (TPP)

Commercially available TPP was used.

(D ₃ ) Phosphate ester oligomer (RDP)

Commercially available resorcinol diphenyl phosphate (RDP) was used. The RDP used here is represented by the above formula (I) and n is 1.4.

(E) fluorinated polyolefin resin

Teflon 7AJ from Mitsui Dupont, Japan, was used.

Table 1 shows the composition and measured physical properties of each component used in Examples 1-2 and Comparative Examples 1-4. Examples 1 to 2 are resin compositions using a triphenyl phosphate mixture substituted with a t-butyl group according to the polycarbonate content as a flame retardant. Comparative Examples 1 to 4 are resin compositions each using TPP and RDP instead of alkylated triphenyl phosphate for comparison with Examples 1 to 2 at all times.

As shown in Table 1, each component was mixed, and antioxidants and heat stabilizers were added, mixed in a conventional mixer, and then introduced into a biaxial compressor having L / D 29 and ￠ = 40 mm. The mixture was prepared into a pellet-type resin composition through an extruder, and a specimen was prepared at an injection temperature of 250 ° C., and then left at 23 ° C. and a relative humidity of 50% for 40 hours to measure physical properties.

TABLE 1

Physical property measurement:

(1) Flame retardancy: measured according to UL 94.

(2) Heat resistance: It measured based on ASTMD306.

(3) Liquid foreign bodies: After the continuous operation for 30 minutes during the injection of physical specimens, the degree of liquid foreign substances due to the volatilization of the flame retardant was observed visually.

(4) Crack generation: The number of cracks was observed after the business card flower was injected at 80 ° C. and left in the oven for 24 hours.

As shown in Table 1, Examples 1 and 2 according to the present invention had no generation of liquid foreign substances and stress cracks compared to Comparative Examples 1 to 4, and were similar or excellent in heat resistance, and also had good flame resistance. Brought the result.

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) 50 to 95% by weight of halogen-free thermoplastic polycarbonate resin; (B) 5-50% by weight of halogen-free rubber modified styrene-containing graft copolymer resin; (C) 0 to 30% by weight of halogen-free styrene-containing copolymer resin; (D) 1-20% by weight trialkylphenyl phosphate, 10-50% by weight dialkyl phenyl monophenyl phosphate, 15-60% by weight monoalkylphenyl diphenyl phosphate, and less than 2% by weight triphenyl phosphate, Alkylated triphenylphosphate used at 3 to 20% by weight relative to 100% by weight of (A) + (B) + (C); And (E) 0 to 2% by weight of a fluorinated polyolefin resin with respect to 100% by weight of (A) + (B) + (C); and a polycarbonate-based thermoplastic resin composition having flame retardancy. The polycarbonate-based thermoplastic resin composition having flame retardancy according to claim 1, wherein the alkyl group is selected from the group consisting of t-butyl, isopropyl, isobutyl and isoamyl groups. The method of claim 1, wherein the fluorinated polyolefin resin (E) is polytetrafluoroethylene, polyvinylidene fluoride, a copolymer of tetrafluoroethylene and vinylidene fluoride, tetrafluoroethylene and fluoroalkyl vinyl ether At least one selected from the group consisting of a copolymer of a copolymer of tetrafluoroethylene and hexafluoropropylene of the polycarbonate-based thermoplastic resin composition having a flame retardancy. The flame retardant polycarbonate-based thermoplastic resin composition of claim 1, wherein the resin composition further comprises an inorganic additive, a carbon fiber, a heat stabilizer, an antioxidant, a light stabilizer, a pigment, and / or a dye.