JPH04266953A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a thermoplastic resin composition composed of a polypropylene resin and a polystyrene resin, having excellent impact resistance, mechanical strength and moldability and giving a molded article having high surface-peeling resistance. CONSTITUTION:The objective composition is produced by compounding (A) 5-98wt.% of a polypropylene resin containing >=1wt.% of a polypropylene modified with a monomer having epoxy group, (B) 95-2wt.% of a polystyrene resin and (C) 2-100 pts.wt. (based on 100 pts.wt. of A+B) of a polystyrene copolymer modified with an unsaturated carboxylic acid or its anhydride.

Description

Detailed Description of the Invention [0001] [Industrial Application Field] The present invention relates to a thermoplastic resin composition containing a polypropylene resin and a polystyrene resin. The present invention relates to a thermoplastic resin composition containing a polypropylene resin having good mechanical strength such as impact resistance and flexural modulus, and a polystyrene resin. [Prior Art] Polypropylene resin has mechanical strength,
It has excellent moldability and chemical resistance, and is widely used in various industrial fields such as inner and outer layer parts of automobiles, home appliance parts, and housings. However, since polypropylene is a non-polar polymer, it has difficulties in secondary processability, particularly in solid phase adhesion and paintability. As a method of modifying such polypropylene, blending polystyrene resin with good paintability into polypropylene has been carried out. However, in addition to being easy to paint, polystyrene resin
Although it has high rigidity and good dimensional stability, it does not have good compatibility with polypropylene, so there is a problem that the physical properties deteriorate significantly. [0003] Therefore, various compositions have been proposed in which a compatibilizer is added to a composition of polypropylene and polystyrene resin for the purpose of improving the compatibility thereof (Japanese Patent Laid-Open No. 87645/1983). No., Japanese Unexamined Patent Publication No. 1-1745
No. 50). [0004] However, all of the above compositions contain a styrene-nonconjugated diene block copolymer or the like as a compatibilizing agent between the polypropylene resin and the polystyrene resin. However, since it is difficult to sufficiently compatibilize polypropylene and polystyrene with the compatibilizing agent described above, there is a problem that the impact resistance, mechanical strength, surface peeling resistance of the molded article, etc. are not necessarily sufficient. Therefore, an object of the present invention is to provide a thermoplastic resin composition of polypropylene resin/polystyrene resin that has excellent impact resistance, mechanical strength, and molding processability, and also suppresses surface peeling of molded products. It is to provide. Means for Solving the Problems In view of the above problems, as a result of intensive research, the present inventors have discovered that polypropylene modified with an epoxy group-containing monomer is used in a composition containing a polypropylene resin and a polystyrene resin. If a polystyrene copolymer modified with an unsaturated carboxylic acid or its anhydride is added as a compatibilizer in a predetermined amount, surface peeling of the molded product can be suppressed and an excellent machine can be obtained. The inventors have discovered that a material having the desired physical properties can be obtained, and have devised the present invention. That is, the thermoplastic resin composition of the present invention comprises (a) 5 to 98% by weight of a polypropylene resin containing 1% by weight or more of polypropylene modified with an epoxy group-containing monomer, and (b) 95 to 98% by weight of a polystyrene resin.
2% by weight, the (a) polypropylene resin, and (
b) It is characterized in that it contains 2 to 100 parts by weight of a polystyrene copolymer modified with an unsaturated carboxylic acid or its anhydride based on a total of 100 parts by weight of the polystyrene resin. The present invention will be explained in detail below. In the present invention, (a) polypropylene resin is polypropylene containing 1% by weight or more of polypropylene modified with an epoxy group-containing monomer. In the above-mentioned modified polypropylene, the polypropylene to be modified is a crystalline polymer polymerized with propylene monomer as a main component, and includes block copolymers or random copolymers of propylene and other α-olefins such as ethylene. Especially propylene
Ethylene random copolymers are preferred. In the case of a random copolymer with ethylene, the ethylene content is preferably 1 to 10% by weight. Such polypropylene is usually 0.0
Melt flow rate (MFR) of 1 to 100 g/10 minutes
, JISK7210, load 2.16kg, 230℃
). A propylene random copolymer (hereinafter referred to as PPDM) containing a non-conjugated diene comonomer may also be used. As explained above, the term "polypropylene" used herein is not limited to homopolymers of propylene, but should be understood to include each of the above-mentioned copolymers. Examples of epoxy group-containing monomers that modify polypropylene include glycidyl methacrylate and glycidyl acrylate. [0013] Also, the following general formula (1): [Formula 2] (wherein, R is H or an alkyl group having 1 to 6 carbon atoms,
Ar is an aromatic hydrocarbon group having 6 to 20 carbon atoms and having at least one glycidyloxy group, and n is 1 to 4.
represents an integer. ) Glycidyl compounds represented by the following can also be used as modifying monomers. Preferred glycidyl compounds include those represented by the following general formula (2). [Formula 3] (In the formula, R is H or an alkyl group having 1 to 6 carbon atoms.) Such a glycidyl compound can be prepared, for example, by the following method shown in JP-A-60-130580. It can be manufactured by First, at least one phenolic hydroxyl group
By condensing an aromatic hydrocarbon having 1 or more with N-methylol acrylamide, N-methylol methacrylamide, or an alkyl ether derivative of N-methylol methacrylamide (hereinafter referred to as N-methylol acrylamides) using an acid catalyst. , the following general formula (3) [Formula 4] (wherein, R is H or an alkyl group having 1 to 6 carbon atoms,
Ar' has at least one hydroxyl group and has 6 carbon atoms
~20 aromatic hydrocarbon groups, and n represents an integer of 1 to 4. ) is produced. The aromatic hydrocarbon having at least one phenolic hydroxyl group is not particularly limited;
For example, phenol, o-cresol, m-cresol,
p-cresol, 2,6-xylenol, 2,4-xylenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, o-phenylphenol,
Phenolic compounds such as 2,6-diphenylphenol, polyphenolic compounds such as hydroquinone, catechol, and phloroglucinol, polycyclic hydroxy compounds such as 1-naphthol, 2-naphthol, and 9-hydroxyanthracene, 2,2-bis (4-hydroxyphenyl)propane (bisphenol-A), bis(4-
Examples include bisphenols such as hydroxyphenyl and methane. Next, by glycidylating the hydroxyl group of the compound represented by the above general formula (3), the compound represented by the general formula (1) is obtained.
A glycidyl compound represented by can be obtained. For this glycidylation, it is preferable to conduct an addition reaction between the compound represented by the general formula (3) and epihalohydrin, and then perform dehydrohalogenation using a caustic alkali. The addition reaction with epihalohydrin is carried out using a phase transfer catalyst. The above epihalohydrin is
Epichlorohydrin, epibromohydrin, epiiodohydrin, etc. can be used. Examples of phase transfer catalysts include quaternary ammonium salts such as tetrabutylammonium bromide, trioctylmethylammonium chloride, benzyltriethylammonium chloride, and quaternary phosphonium salts such as tetraphenylphosphonium chloride and triphenylmethylphosphonium chloride. Salt etc. can be used. The amount of the phase transfer catalyst used is determined by the general formula (3
) as 100 mol%, 0.0
It is preferably used in a range of 1 to 100 mol%. A particularly preferred amount of phase transfer catalyst used is 0.05 to 10 mol%. In addition, the reaction time and reaction temperature are 50 to 120
5 minutes to 2 hours at ℃, more preferably 80 to 110 ℃
It takes 10 to 30 minutes. Subsequently, dehydrohalogenation is performed using caustic alkali. The above caustic alkali includes caustic soda,
Caustic potash, lithium hydroxide, etc. can be used. These can be used as solids or as aqueous solutions. Further, as a catalyst for dehydrohalogenation, the same one as the above-mentioned phase transfer catalyst can be used. Catalysts other than the above phase transfer catalysts include crown ethers,
Examples include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and the like. The amount of the caustic alkali used is determined by the general formula (3
) It is preferred to use equimolar amounts with respect to the compound represented by. More preferably, 1.1 to 1.5 times the molar amount is used. In addition, the reaction time and reaction temperature are 20 to 90°C for 10 minutes to 30 minutes.
The time is preferably 30 minutes to 2 hours at 40 to 70°C. The polypropylene modified with an epoxy group-containing monomer may be a block copolymer, a graft copolymer, a random copolymer, or an alternating copolymer. [0025] The content of the epoxy group-containing monomer in the modified polypropylene is preferably within the range of 0.1 to 15% by weight, and when the above-mentioned glycidyl compound containing an epoxy group is used. The content should be 0.1 to 15% by weight, more preferably 0.1 to 15% by weight.
2 to 15% by weight. If the amount of modification by the epoxy group-containing monomer is less than the above lower limit, there will be no sufficient effect on improving the compatibility between the polypropylene resin and the polystyrene resin, and if it exceeds the upper limit, the mechanical strength will decrease. The modified polypropylene can be produced by either a solution method or a melt-kneading method. In the case of the melt-kneading method, polypropylene, an epoxy group-containing monomer for modification, and a catalyst are charged into an extruder, twin-screw kneader, etc.
The mixture is heated to a temperature of 300°C, preferably 180 to 250°C, and kneaded while melting. In the case of a solution method, the above starting material is dissolved in an organic solvent such as xylene, and the starting material is dissolved in an organic solvent such as xylene.
It is carried out at a temperature of 140° C. with stirring. The amount of the epoxy group-containing monomer added at this time is 0.1 to 20 parts by weight, preferably 0.5 parts by weight, per 100 parts by weight of polypropylene.
~10 parts by weight. In either case, a conventional radical polymerization catalyst can be used as a catalyst, such as benzoyl peroxide, lauroyl peroxide, ditertiary butyl peroxide, acetyl peroxide, tertiary butyl peroxybenzoic acid, dicumyl peroxide, Peroxides such as peroxybenzoic acid, peroxyacetic acid, tert-butyl peroxy pivalate, 2,5-dimethyl-2,5-diter-butyl peroxyhexine, diazo compounds such as azobisisobutyronitrile, etc. is preferred. The amount of catalyst added is 1 epoxy group-containing monomer for modification.
The amount is about 1 to 100 parts by weight per 00 parts by weight. Furthermore, a phenolic antioxidant can be added during the graft reaction, but it is preferable not to add it if a radical polymerization catalyst is not added. The content of the above-mentioned modified polypropylene in the polypropylene resin is 1% by weight or more based on 100% by weight of the polypropylene resin (a). If the content of the modified polypropylene is less than 1% by weight, there is no sufficient effect in improving the compatibility between the polypropylene resin and the polystyrene resin. Moreover, if it exceeds 90% by weight, the melt flow rate increases too much. The preferred content of modified polypropylene is about 3 to 60% by weight. However, the entire polypropylene resin is 10
It is preferable that the content of the epoxy group-containing monomer is 0.005% by weight or more. If the content of the epoxy group-containing monomer is less than 0.005% by weight based on the entire polypropylene resin, there is no sufficient effect in improving the compatibility between the polypropylene resin and the polystyrene resin. [0030] In the polypropylene resin, polypropylene other than modified polypropylene is not particularly limited as long as it is a polymer containing propylene as a main component;
It may also be copolymerized with other α-olefins such as ethylene, butene, 4-methylpentene-1, etc. up to about % by weight. The copolymer may be either a random copolymer or a block copolymer. Further, a copolymer rubber of two or more α-olefins such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-pentene, or α-
It may contain up to about 40% by weight of an olefin thermoplastic elastomer such as a copolymer rubber of olefin and other monomers. [0031] The copolymer rubber of two or more α-olefins typically includes ethylene-propylene copolymer rubber (EPR), ethylene-butene copolymer rubber (EBR), and ethylene-propylene copolymer rubber (EBR). Examples include propylene-diene copolymer rubber (EPDM). The melt flow rate (MFR, 230° C., 2.16 kg load) of such a polypropylene resin is preferably 0.1 to 100 g/10 minutes. If the melt flow rate is less than 0.1 g/10 minutes, the moldability of the resulting thermoplastic resin composition will be poor, and
If it exceeds 0.00 g/10 minutes, impact resistance will decrease, which is not preferable. In the present invention, the polystyrene resin (b) is a homopolymerized styrene monomer;
Alternatively, it may be copolymerized with about 5 to 50% by weight of other monomers. As a comonomer for copolymerization,
Examples include α-methylstyrene, acrylonitrile, maleic anhydride, methyl methacrylate, and the like. Further, rubber-modified polystyrene obtained by emulsion polymerizing about 10 to 30% by weight of a rubbery polymer such as polybutadiene or butadiene-styrene copolymer to styrene can also be used. [0034] Furthermore, polyphenylene ether resin is about 1 to 99% by weight when polystyrene is 100% by weight.
(PPO) can also be used. The above polyphenylene ether resin is represented by the following general formula (4). embedded image (wherein, R1 and R2 are an alkyl group having 1 to 4 carbon atoms, an aryl group having 4 to 8 carbon atoms, a halogen atom, or a hydrogen atom, and may be the same or different, n
indicates a number from 50 to 500. ) Such polyphenylene ether resins include, for example, poly(2,6-dimethyl-1,4-phenylene) ether, poly(2,6-diethyl-1,
4-phenylene) ether, poly(2-methyl-6
-ethyl-1,4-phenylene) ether, poly(2
-methyl-6-isopropyl-1,4-phenylene)
Ether, poly(2-methyl-1,4-phenylene)
Ether, poly(2,6-dichrome-1,4-phenylene) Ether, poly(2-ethyl-6-bromo-1,
4-phenylene) ether, poly(2-phenyl-1
, 4-phenylene) ether, and the like. Melt index of polystyrene resin as described above (MI: 190°C, 2.16 kg load)
is preferably about 0.5 to 20 g/10 minutes. The blending ratio of (a) polypropylene resin and (b) polystyrene resin as described above is (
When a) + (b) is 100% by weight, (a) is 5
-98% by weight, preferably 10-90% by weight, (
b) 95-2% by weight, preferably 90-10% by weight
It is. (a) If the polypropylene resin is less than 5% by weight (if (b) exceeds 95% by weight), the mechanical strength, moldability, chemical resistance, etc., which are the characteristics of polypropylene, will decrease; If the amount of the resin exceeds 98% by weight (if (b) is less than 2% by weight), the effect of improving the rigidity by the posttyrene resin will not be sufficient. In the present invention, in (c) a polystyrene copolymer modified with an unsaturated carboxylic acid or its anhydride, the polystyrene copolymer refers to a copolymer consisting of a polystyrene portion and a polyolefin portion, or a copolymer consisting of a polystyrene portion and a polyolefin portion, or These may be either block or graft copolymers depending on the type of polyolefin to be copolymerized. Examples of such polystyrene copolymers include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and styrene-hydrogenated isoprene-based copolymer.
Styrene block copolymer (SEPS), styrene-hydrogenated butadiene-styrene block copolymer (SEBS)
) etc. Among the above polystyrene copolymers, styrene-hydrogenated isoprene-styrene block copolymer (SEPS) and styrene-hydrogenated butadiene-styrene block copolymer (SEBS) are particularly preferred in terms of weather resistance. preferable. The above styrene-hydrogenated isoprene-styrene block copolymer (SEPS) has the following general formula (2).
It is expressed by (S-EP)n-Sm・
...(5) (In the formula, S is a polystyrene part, and EP is a hydrogenated polyisoprene part (ethylene/propylene part)
, n is an integer from 1 to 20, and m is 0 or 1. ) The above-mentioned styrene-hydrogenated isoprene-styrene block copolymer includes a two-block type (SEP when n=1 and m=0) and a three-block type (SEP when n=1 and m=0). 1), and a multi-block type (in the case of n=2 to 20), but any of them can be used in the present invention. The above-mentioned styrene-hydrogenated isoprene-styrene block copolymer is prepared by subjecting the styrene-isoprene-styrene block copolymer to 25 to By hydrogenating at a temperature of 175°C, only the isoprene portion is selectively hydrogenated, resulting in a structure corresponding to an ethylene-propylene copolymer. In the above styrene-hydrogenated isoprene-styrene block copolymer, it is not necessary that all of the isoprene portion is hydrogenated, as long as 5% or more is hydrogenated. The preferred hydrogenation ratio is 50% or more, more preferably 80% or more. The styrene-hydrogenated isoprene-styrene block copolymer has been explained above, but the styrene-hydrogenated isoprene-styrene block copolymer
Hydrogenated butadiene-styrene (SEBS) is the same as in the above description except that isoprene is replaced with butadiene. In the present invention, the content of the styrene moiety in such a polystyrene copolymer is from 40 to 95% by weight, preferably from 40 to 80% by weight. If the styrene portion is less than 40% by weight, the effect of improving the compatibility between (a) polypropylene resin and (b) polystyrene resin will not be sufficient, while if it exceeds 95% by weight, it will become brittle. [0048] In the polystyrene copolymer, the styrene portion is not limited to only styrene, but may also be composed of substituted styrene such as methylstyrene. The weight average molecular weight of such a polystyrene copolymer is preferably from 2 x 104 to 50 x 104, particularly preferably from 5 x 104 to 35 x 104. If the weight average molecular weight is less than 2 x 104, the melt viscosity is too low;
On the other hand, if it exceeds 50×10 4 , the melt viscosity becomes too high and moldability deteriorates, which is not preferable. Examples of unsaturated carboxylic acids or anhydrides thereof for modifying such polystyrene copolymers include monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid, itaconic acid, and endo-bicyclo −
Dicarboxylic acids such as [2,2,1]-5-heptene-2,3-dicarboxylic acid, maleic anhydride, itaconic anhydride, endo-bicyclo-[2,2,1]-5-heptene-2,3 Dicarboxylic acid anhydrides such as -dicarboxylic anhydride (himic anhydride) are mentioned, and dicarboxylic acids and their anhydrides are particularly preferred. Modification of the polystyrene copolymer with such an unsaturated carboxylic acid or its anhydride may be carried out by graft polymerization or random copolymerization. In the case of graft polymerization, first, a polystyrene copolymer, an unsaturated carboxylic acid or its anhydride for modification, and a catalyst if necessary are charged into an extruder or twin-screw kneader, etc. ~300℃, preferably 180℃
Knead while melting at about ~250°C. The amount of the unsaturated carboxylic acid or its anhydride added is about 0.1 to 20 parts by weight, preferably about 0.5 to 10 parts by weight, per 100 parts by weight of the polystyrene copolymer. [0053] As the catalyst to be added as necessary during the above melt-kneading, a usual radical polymerization catalyst can be used, such as benzoyl peroxide, lauroyl peroxide,
Ditert-butyl peroxide, acetyl peroxide, tert-butyl peroxybenzoic acid, dicumyl peroxide, peroxybenzoic acid, peroxyacetic acid, tert-butyl peroxypivalate, 2,5-dimethyl-2,5-
Peroxides such as ditertiary-butylperoxyhexine and diazo compounds such as azobisisobutyronitrile are preferred. The amount of the catalyst added is about 0.01 to 3 parts by weight per 100 parts by weight of the polystyrene copolymer. [0054] The content of unsaturated carboxylic acid or its anhydride in the modified polystyrene copolymer is preferably within the range of 0.01 to 10% by weight. In the case of modification with maleic acid, the content of maleic anhydride is 0.1 to 10% by weight, more preferably 0.2 to 10% by weight, and in the case of using himic anhydride, the content is The amount is 0.1 to 10% by weight, more preferably 0.2 to 10% by weight. If the amount of modification by maleic anhydride and himic anhydride is less than the above lower limit, there will be no sufficient effect on improving the compatibility between the polypropylene resin and the polystyrene resin,
Moreover, when the upper limit is exceeded, the mechanical strength decreases. The amount of the above (c) polystyrene copolymer modified with an unsaturated carboxylic acid or its anhydride is based on 100 parts by weight of the total amount of (a) polypropylene resin and (b) polystyrene resin. Te 2-100
Parts by weight. If the amount of the polystyrene copolymer modified with an unsaturated carboxylic acid or its anhydride is less than 2 parts by weight, the effect of improving compatibility due to its addition is insufficient, resulting in poor impact resistance and surface peeling resistance. Sexuality, etc. becomes insufficient. Moreover, if it exceeds 100 parts by weight, fluidity and rigidity will decrease. The preferred amount of (c) polystyrene copolymer modified with unsaturated carboxylic acid or its anhydride is 5 to 50 parts by weight. The thermoplastic resin composition of the present invention may further contain inorganic fillers such as talc and calcium carbonate, reinforcing materials such as glass fiber and carbon fiber, thermal stabilizers, and antioxidants for the purpose of modifying the composition. , light stabilizers, flame retardants, plasticizers,
Antistatic agents, mold release agents, foaming agents, etc. can be added. The thermoplastic resin composition of the present invention as described above can be prepared by mixing the above-mentioned components in a kneading machine such as a single screw extruder, a twin screw extruder, a Banbury mixer, a kneading roll, a Brabender, a kneader, or a Henschel mixer. Using a machine, 1
80-320°C, preferably 200-280°C
It can be obtained by kneading in a heated molten state. Alternatively, each of the above components may be divided and kneaded, and the respective masterbatches may be kneaded together. [Operation] The thermoplastic resin composition of the present invention is a composition containing a polypropylene resin and a polystyrene resin, in which the polypropylene resin contains a certain amount of polypropylene modified with an epoxy group-containing monomer. In addition, a predetermined amount of a polystyrene copolymer modified with an unsaturated carboxylic acid or its anhydride is added as a compatibilizer, so surface peeling of the molded product is suppressed and it has excellent mechanical properties. . Although the reason why such an effect is obtained is not necessarily clear, polystyrene copolymers modified with unsaturated carboxylic acids or their anhydrides are compatible with polystyrene resins, and at the same time, the polystyrene copolymers modified with unsaturated carboxylic acids or their anhydrides are This is thought to be because it forms a graft copolymer with modified polypropylene, and thus exhibits an excellent function as a compatibilizer between polypropylene resin and polystyrene resin. EXAMPLES The present invention will be explained in more detail with reference to the following examples. Note that the following resins were used as raw material resins in each of the Examples and Comparative Examples. [1] Polypropylene resin HPP: Propylene homopolymer [J-209, manufactured by Tonen Chemical Co., Ltd., melt flow rate (MFR, 230
°C, 2.16 kg load) 8.5 g/10 minutes] [2] Ethylene-propylene copolymer rubber EPR: [
Made by Japan Synthetic Rubber Co., Ltd., EP02P] [3] Polystyrene resin PS: [GP-666, made by Asahi Kasei Co., Ltd., MFR (
200°C, 5 kg load) 7.5 g/10 minutes] [4] Modified polystyrene copolymer CMSEBS-1: Maleic anhydride (MAH) Modified styrene-hydrogenated butadiene-styrene block copolymer [
Maleic anhydride content 2% by weight, weight average molecular weight 14.
5×104, polystyrene content 31% by weight] CMSEBS-2: Maleic anhydride (MAH) modified styrene-hydrogenated butadiene-styrene block copolymer [
Maleic anhydride content 2% by weight, weight average molecular weight 7.5
×104, polystyrene content 29% by weight] [5] Epoxy group-containing modifying monomer AXE: glycidyl compound represented by the following chemical formula [Kanebuchi Chemical Co., Ltd.]
Synthesis Example 1 of Epoxy-Modified Polypropylene Polypropylene homopolymer (manufactured by Tonen Chemical Co., Ltd.: Y20)
1. Melt flow rate (MFR, 230℃2.1
6kg load) 1.5g/10 minutes) 100 parts by weight,
Mixed with 3 parts by weight of the above-mentioned AXE and 0.1 part by weight of POX (radical generator: Perhexine 2-5B, manufactured by NOF Corporation), and using a twin screw extruder with a diameter of 45 mm,
The mixture was kneaded at 200° C. and 100 rpm to obtain epoxy-modified polypropylene (CMPP-1). The melt flow rate of the obtained modified polypropylene was 28.0 g/10 minutes, and the grafting rate of AXE was 2.4% by weight. [0063] The grafting rate of AXE is determined by dissolving modified polypropylene in boiling xylene and removing insoluble matter.
Dissolved components were precipitated with methanol, and this was
The infrared absorption spectrum of the AXE was measured and the peak (16
48 cm-1) and one of the peaks (840 cm-1) characteristic of isotactic polypropylene. Synthesis example 2A of epoxy-modified polypropylene
Epoxy-modified polypropylene (CMPP-2) was obtained in the same manner as Synthesis Example 1 of modified polypropylene except that the amount of XE added was 1 part by weight. The melt flow rate of the obtained modified polypropylene was 33.0 g/10 minutes, and the grafting rate of AXE was 1.0% by weight. Synthesis example 3A of epoxy-modified polypropylene
Epoxy-modified polypropylene (CMPP-3) was obtained in the same manner as Synthesis Example 1 of modified polypropylene except that the amount of XE added was 2.5 parts by weight. The melt flow rate of the obtained modified polypropylene was 54.0 g/10
minutes, and the grafting rate of AXE was 2.0% by weight. Examples 1 to 8 Polypropylene (HPP), ethylene-propylene copolymer rubber (EPR), polystyrene (PS), epoxy modified polypropylene (CMPP-1 to 3), modified polystyrene copolymer (CMSEBS-1) Alternatively, the pellets of each resin in 2) are mixed at room temperature in a Henschel mixer in the proportions shown in Table 1, then kneaded at 250 °C and 200 rpm using a 45 mmφ twin-screw kneader, and the discharged product is rapidly cooled in water. Pellets of a thermoplastic resin composition were obtained. For each thermoplastic resin composition obtained,
Melt flow rate, surface peeling resistance, elongation at break, flexural modulus, Izod impact strength and surface peeling property were measured. The results are shown in Table 2. Comparative Example 1 Melt flow rate and
Surface peeling resistance, elongation at break, flexural modulus, Izod impact strength and surface peeling were measured. The results are shown in Table 2. Comparative Examples 2 to 4 Regarding compositions prepared by adding 5 parts by weight of an unmodified polystyrene copolymer to 80 parts by weight of polypropylene and 20 parts by weight of polystyrene, melt flow rate, surface peeling resistance, The elongation at break, flexural modulus, Izod impact strength and surface peelability were measured. The results are shown in Table 2. [0070] As the unmodified polystyrene copolymer, styrene-hydrogenated butadiene-styrene block copolymer (SEBS: manufactured by Shell Chemical Co., Ltd., Kraton
G-1652), styrene-hydrogenated isoprene block copolymer (SEP: Shell Chemical Co., Ltd., Kraton G-
1701) and styrene-butadiene rubber (SBS: manufactured by Asahi Kasei Industries, Ltd., Tuffrene A) were used. Comparative Example 5 Melt flow rate and surface peeling resistance of a composition prepared by adding only 5 parts by weight of a modified polystyrene copolymer (SEBS-1) to 80 parts by weight of polypropylene and 20 parts by weight of polystyrene. The strength, elongation at break, flexural modulus, Izod impact strength and surface peelability were measured. The results are shown in Table 2. Comparative Example 6 65 parts by weight of polypropylene, 15 parts by weight of ethylene-propylene copolymer rubber (EPR), and 2 parts by weight of polystyrene
0 parts by weight, styrene-hydrogenated butadiene-styrene block copolymer (SEBS: Shell Chemical Co., Ltd., Krato
Regarding the composition containing 5 parts by weight of nG-1652), the melt flow rate, surface peeling resistance, elongation at break,
Flexural modulus, Izod impact strength and surface peelability were measured. The results are shown in Table 2. Comparative Example 7 Melt flow rate, surface peeling resistance, elongation at break, flexural modulus, Izod impact strength, and surface peeling property were measured for the composition in Example 1 without adding the modified polystyrene copolymer. did. The results are shown in Table 2. [0074] No.
1 Table Composition


(Parts by weight) Example 1 Example 2 Example 3 Example 4
HPP 65
65 65
65 EPR
− −
− −
PS20
20 20
20
CMPP-1 15
− −
15 CMPP-
2-15
− −
CMPP-3
− −
15-
CMSEBS-1 5
5 5
- CMSEB
S-2 - -
-5
[0075] No.
1 Table (continued) Composition

(Parts by weight) Example 5 Example 6 Example 7 Example 8 HPP
70 50
50 67
EPR-
15-
- P.S.
20 20
20 20
CMPP-1
10 15
30 15
CMPP-2 −
− −
-C
MPP-3-
− − −
CMSEBS-1
-5
5 3
CMSEBS-2 5
− −
-0076
1 Table (continued) Group
Growth

(Parts by weight) Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4
HPP
80 80 8
0 80
EPR-
− −
- P.S.
20 20
20 20
SEBS-
5-
-SEP
− −
5-
SEB-
− −
5 CM
PP-1

CMSEBS-
1 - -
− −
[0077] No.
1 Table (continued) Group
Growth

(Parts by weight) Comparative example 5 Comparative example 6 Comparative example 7
HPP
80 65
65
EPR-
15-
P.S.
20 2
0 20
SEBS
-5
−
SEP-
− −
SEB
− −
−
CMPP-1-
-15

CMSEBS-1 5
− − 0078
2 Table physical properties
Example 1 Example 2 Example 3
Example 4 MFR (g/10 min)
(1) 16 18
20 20
Elongation at break (%) (2) 15
15 16
20 Flexural modulus (3)
17100 170
00 16700 1650
0 (kg/cm2)


Izod impact strength (4) 2.1
2.5 2.3
2.5 (kgf cm/cm)


Surface removability (5)
100/100 90/100 10
0/100 100/100 0079
] No.
2 Table (continued) Physical properties
Example 5 Example 6
Example 7 Example 8 MFR (
g/10 minutes) (1) 19
13 18
15 Elongation at break (%) (2)
13 25
18 16 Flexural modulus (3) 16700
12900 16800
17100 (kg/cm2)


Izod impact strength (4)
2.2 9.0
2.0 2.2 (kgf
cm/cm)

Surface removability (5)
92/100 90/10
0 100/100 85/10
0 0080
2 Table (continued)
physical properties
Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 MFR (g/10
minutes) (1) 14 8
9 9
Elongation at break (%) (2) 5
16 12
13 Flexural modulus (3)
15500 1410
0 13600 14700
(kg/cm2)


Izod impact strength (4) 1.5
3.4 4.3
2.3 (kgf cm/cm)


Surface removability (5)
0/100 20/100 4/10
0 10/100 0081] No.
2 Table (continued)
physical properties
Comparative example 5 Comparative example 6 Comparative example 7
MFR (g/10 min) (1)
10 8
12 Elongation at break (%) (2
) 11 80
6 Flexural modulus (3
) 13900 1
0600 15000
(kg/cm2)

Izod impact strength (4)
3.0 7.8
1.6 (kgf cm/cm
)

Surface removability (5) 12/10
0 30/100 0/100
(1) Melt flow rate: JIS K
Measured at 230°C and 2.16kg load according to 6758. (2) Elongation at break: Measured according to JIS K7113. (3) Flexural modulus: Measured according to JIS K7203. (4) Izod impact strength: Measured at 23°C in accordance with JIS K7110 (notched). (5) Surface releasability: Molded product (70 mm x 120 m
Use a razor to cut 1mm onto the surface of the injection material (m x 3mm)
100 x 1 mm squares were formed, cellophane tape (manufactured by Nichiban Co., Ltd.) was attached to the squares, and then removed. 1
Out of 00 squares, the number that remained on the surface of the molded product without adhering to the cellophane tape was counted. As is clear from Table 2, Examples 1 to 8
The thermoplastic resin composition had good surface peelability, elongation at break, impact resistance, and flexural modulus. On the other hand, the thermoplastic resin composition of Comparative Example 1, which was a two-component composition of polypropylene and polystyrene, had extremely poor surface peeling resistance, and also had poor elongation at break and impact resistance values. Furthermore, the thermoplastic resin compositions of Comparative Examples 2 to 7 had poor surface peeling resistance. Effects of the Invention As detailed above, the thermoplastic resin composition of the present invention is a composition containing a polypropylene resin and a polystyrene resin. A material containing a certain amount of modified polypropylene is used, and a predetermined amount of a polystyrene copolymer modified with an unsaturated carboxylic acid or its anhydride is added as a compatibilizer. Therefore, the thermoplastic resin composition of the present invention suppresses surface peeling of molded articles thereof and has excellent mechanical properties. The thermoplastic resin composition of the present invention is suitable for use as an engineering plastic material, particularly for parts of automobiles and household electrical appliances.

Claims (3)

[Claims] 1. (a) 5 to 98% by weight of a polypropylene resin containing 1% by weight or more of polypropylene modified with an epoxy group-containing monomer; (b) 95 to 2% by weight of a polystyrene resin; and (a) the polypropylene. Total of 100% of polystyrene resin and (b) polystyrene resin
Based on parts by weight, (c) 2 to 10 polystyrene copolymers modified with unsaturated carboxylic acid or its anhydride;
0 parts by weight of a thermoplastic resin composition. 2. The thermoplastic resin composition according to claim 1, wherein the polystyrene copolymer comprises styrene-
The heat is selected from a butadiene-styrene block copolymer, a styrene-butadiene block copolymer, a styrene-hydrogenated butadiene-styrene block copolymer, and a styrene-hydrogenated butadiene block copolymer. Plastic resin composition. 3. The thermoplastic resin composition according to claim 1 or 2, wherein the epoxy group-containing monomer has the following general formula: [Formula 1] (wherein R is H or an alkyl group having 1 to 6 carbon atoms and
A thermoplastic resin characterized in that it is a glycidyl compound represented by Ar is an aromatic hydrocarbon group having 6 to 20 carbon atoms and having at least one glycidyloxy group, and n is an integer of 1 to 4. Composition.