JP2000186177A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin composition having good compatibility and excellent in heat resistance, oil resistance, chemical resistance, impact resistance, stiffness and tensile strength and capable of readily providing molded product which is most suitable for food vessels, extrusion sheets for food vessels as well as general household electric appliances, various kind of industrial parts, general household utensils, etc. SOLUTION: This thermoplastic resin comprises (A) 50-95 pts.wt. styrene-based resin, (B) 50-5 pts.wt. propylene-based resin and (C) 0.1-25 wt.% ethylene-α-olefin copolymer rubber having <4.0 extent of molecular weight distribution (Mw/Mn) calculated by gel permeation chromatography(GPC) and being a ratio of weight average molecular weight(Mw) to number-average molecular weight(Mw) and (D) 0.1-25 wt.% styrene-based block copolymer rubber based on 100 pts.wt. total amount of these components A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a styrene-based resin and a propylene-based resin having good compatibility and excellent heat resistance, oil resistance, chemical resistance, impact resistance, rigidity and tensile strength. The present invention relates to a thermoplastic resin composition.

[0002]

2. Description of the Related Art Styrene resin has good moldability, impact resistance,
As an inexpensive general-purpose resin having a good balance of rigidity and the like, it is widely used in food packaging materials, home appliances, industrial parts, household goods, and the like. In particular, in food packaging material applications, various food containers are manufactured from extruded sheets and extruded foam sheets by thermoforming, vacuum forming and the like. However, on the other hand, styrene resin containers may not be able to cope with applications that require a high degree of oil resistance and chemical resistance due to the variety of products that come into contact with them.

Therefore, conventionally, the oil resistance of styrene resin,
A resin composition consisting of a styrene-based resin and an olefin-based resin has been studied to improve chemical resistance, but both resins have poor compatibility, and the composition has reduced mechanical strength and delamination also occurs. And it was not practical. In addition, a technique for improving the compatibility of the resin composition has also been studied. For example, a method of adding a styrene-butadiene block copolymer rubber or a styrene-grafted (ethylene-propylene) rubber has been known. It was not satisfactory. Further, in order to improve oil resistance and chemical resistance, it is necessary to knead a considerable amount of a polyolefin resin, and there is a problem that dimensional stability and rigidity, which are characteristics of styrene resins, are impaired.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a styrene resin and a propylene resin having good compatibility and excellent heat resistance, oil resistance, chemical resistance, impact resistance, rigidity and tensile strength. To provide a thermoplastic resin composition comprising:

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, ethylene-α-olefin copolymer rubbers specific to styrene resins and propylene resins, and By solving the above problems by using a styrene-based block copolymer rubber in combination, a resin composition having good compatibility, excellent heat resistance, oil resistance, chemical resistance, impact resistance, rigidity, and tensile strength. Heading, the present invention has been reached.

That is, the present invention relates to (A) 50 to 95 parts by weight of a styrene resin, (B) 50 to 5 parts by weight of a propylene resin, and (A) + (B) a total of 100 parts by weight, C) Weight average molecular weight (Mw) calculated by gel permeation chromatography (GPC)
Molecular weight distribution (Mw), which is the ratio between the number average molecular weight (Mn)
/ Mn) is less than 4.0, containing 0.1 to 25% by weight of an ethylene-α-olefin copolymer rubber and (D) 0.1 to 25% by weight of a styrene-based block copolymer rubber. Characteristic thermoplastic resin composition.

Hereinafter, the present invention will be described in detail. As the styrene resin (A) of the present invention, a resin obtained by homopolymerizing or copolymerizing a styrene monomer or a rubber-modified styrene resin can be used. As the styrene-based monomer, in addition to styrene, α-methylstyrene, α-methyl p
-Methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, t-butylstyrene, bromostyrene, chlorostyrene, indene and the like are preferred, but styrene is preferred. Two or more of these styrene monomers can be used.

In the present invention, if necessary, another unsaturated monomer copolymerizable with the styrene monomer may be used in combination. Other copolymerizable unsaturated monomers include unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and (meth) such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl acrylate. Examples thereof include alkyl esters of unsaturated carboxylic acids such as acrylic acid esters, and acrylonitrile, maleic anhydride, and ferenyl maleimide. These can be used in combination of two or more.

The rubber-modified styrene resin can be produced by polymerizing a styrene monomer in the presence of a conjugated diene rubber. As a conjugated diene rubber,
Polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer and the like can be used, but polybutadiene or styrene-butadiene copolymer is preferred. As polybutadiene, both high cis polybutadiene having a high cis content and low cis polybutadiene having a low cis content can be used. The styrene-butadiene copolymer may have any of a random structure and a block structure. One or more of these conjugated diene rubbers can be used.

The component (A) of the present invention is preferably a rubber-modified styrene resin or a combination of a rubber-modified styrene resin and a non-rubber-modified styrene resin. The content of the system rubber is 1 to 15% by weight. If the rubber content is less than 1% by weight, the impact resistance decreases, and if it exceeds 15% by weight, the surface appearance deteriorates. Further, a preferable average rubber particle diameter is in a range of 0.15 to 2.5 μm. If the average rubber particle diameter is smaller than 0.15, the impact resistance is not sufficient,
If it exceeds μm, a good surface appearance cannot be obtained.

The propylene resin (B) used in the present invention is not particularly limited as long as it is a crystalline polymer obtained by polymerizing a propylene monomer as a main component, and examples thereof include ethylene, butene and 2-methylpentene-1. It may contain any copolymerizable monomer unit. Particularly preferred propylene-based resins are polypropylene homopolymer resins and block copolymer resins of propylene monomer units and ethylene monomer units.

The ethylene-α component (C) used in the present invention
-The olefin copolymer rubber has a molecular weight distribution (Mw / Mn) of 4.0, which is the ratio between the weight average molecular weight (Mw) and the number average molecular weight (Mn), calculated by gel permeation chromatography (GPC). Less than at least one α having ethylene and 3 to 12 carbon atoms
-Consisting of olefins. Specifically, it is composed of ethylene and at least one or more α-olefins having 3 to 12 carbon atoms and / or a non-conjugated diene, and is characterized by being produced by a known metallocene catalyst. Carbon number 3
Α-olefin of -12, propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, nonene-
1, decene-1, undecene-1, dodecene-1 and the like. Preferably, it is octene-1. Examples of the non-conjugated diene include alkenyl norbornenes, cyclic dienes, and aliphatic dienes.
Ethylidene-2-norbornene and dicyclopentadiene.

The metallocene catalyst is composed of a cyclopentadienyl derivative of a group IV metal such as titanium or zirconium and a co-catalyst. The metallocene catalyst is not only highly active as a polymerization catalyst but also a conventional catalyst such as a Ziegler catalyst. Compared to,
It is characterized in that the molecular weight distribution of the obtained polymer and the composition distribution of the comonomer α-olefin having 3 to 12 carbon atoms in the copolymer are narrow and the catalyst species are uniform. By using the catalyst, it becomes possible to increase the composition ratio of the comonomer more than in the conventional art, and it is possible to obtain an elastomeric polymer having excellent flexibility and low modulus.

Further, ethylene and α with a Ziegler catalyst
-In the case of an olefin copolymer which is a copolymer of olefin, a temperature of 190 ° C /
A melt index (I10) at 10 kgf;
The ratio (I10 / I2) to the melt index (I2) at 190 ° C./2.16 kgf and the molecular weight distribution show a substantially linear proportional relationship, and the molecular weight distribution tends to increase as the melt index ratio increases. The molecular weight distribution is about 4 to 10. On the other hand, in the case of an olefin polymer using a metallocene catalyst, the molecular weight distribution is sharp at a value of less than 4.0 regardless of the value of the melt index ratio, and the low molecular weight component is extremely small.

The present invention provides an ethylene-α-olefin copolymer rubber using a metallocene catalyst,
The balance of impact resistance, rigidity, gloss and oil resistance is excellent. Ethylene-α-olefin copolymer rubber,
Those having a density in the range of 0.83 to 0.92 g / cm ³ are preferred. If it is higher than 0.92 g / cm ^3, flexibility is reduced and impact resistance is reduced. The melt index of the base olefin polymer used in the present invention is not particularly limited, but may be 0.01 to 300 g / 10 min (190
C., 2.16 kg load), more preferably 0.05 to 100 g / 10 min, even more preferably 0.5 to 50 g / 10 min.

The content of α-olefin in the ethylene-α-olefin copolymer rubber is preferably 5 to 50% by weight, more preferably 10 to 30% by weight. When the content of the α-olefin is less than 5% by weight, the flexibility of the copolymer rubber is reduced, so that the impact resistance of the composition is reduced. When a diene is used, the content of the non-conjugated diene in the ethylene-α-olefin copolymer rubber is 1 to 30% by weight, preferably 1 to 15% by weight.

The above-mentioned ethylene-α-olefin copolymer rubber is easily available. For example, “ENGAGE” (trade name) manufactured by Dupont Dow Elastomer, “AFFINITY” (trade name) manufactured by Dow Chemical Company, etc. are available. No. Styrene block copolymer rubber (D) of the present invention
Is a polymer block 1 composed of a styrene monomer.
A block copolymer composed of at least one polymer block and at least one polymer block composed of a conjugated diene monomer is used, and a polymer block composed of a conjugated diene monomer is partially or wholly. May be hydrogenated.

The styrene monomer is preferably styrene among the aforementioned styrene monomers. Examples of the conjugated diene-based monomer include butadiene, isoprene, piperylene, methylpentadiene, and phenylbutadiene, but butadiene or isoprene is preferred. Both styrene-based monomers and conjugated diene-based monomers can be used in combination of two or more. Of these styrene block copolymer rubbers, hydrogenated styrene-butadiene block copolymers are particularly preferred. These block copolymer rubbers are commercially available and can be manufactured by methods well known to those skilled in the art. In the composition of the present invention,
The composition ratio of (A) styrene resin and (B) propylene resin is (A) 50 to 95 parts by weight of styrene resin,
(B) 50 to 5 parts by weight of a propylene-based resin. (A)
If the component is 50 parts by weight or less, the dimensional stability and rigidity are poor, and 9
If it exceeds 5 parts by weight, sufficient oil resistance and chemical resistance cannot be obtained.

The composition ratio of (C) an ethylene-α-olefin copolymer rubber having a molecular weight distribution (Mw / Mn) of less than 4.0 and (D) a styrene copolymer rubber is as follows:
For the total of 100 parts by weight of the components (A) and (B),
(C) 0.1 to 25% by weight of an ethylene-α-olefin copolymer rubber having a molecular weight distribution (Mw / Mn) of less than 4.0, and (D) 0.1 to 25% of a styrene-based copolymer rubber % By weight. More preferably, component (C) is 1 to 20% by weight and component (D) is 1 to 20% by weight. If the components (C) and (D) are less than 0.1% by weight, the compatibility is not sufficient and the mechanical strength is poor. If the amount exceeds 25% by weight, the rigidity decreases.

The thermoplastic resin composition of the present invention may optionally contain optional additives used in ordinary thermoplastic resins. For example, silica, calcium carbonate,
Inorganic fillers such as magnesium carbonate, calcium sulfate, and talc; coloring agents such as organic fibers, titanium oxide and carbon black; lubricants such as stearic acid, zinc stearate, calcium stearate, and ethylenebisstearylamide;
Release agents, plasticizers such as organic polysiloxanes and mineral oils, antioxidants such as hindered ferules and phosphorus, flame retardants, ultraviolet absorbers, antistatic agents, reinforcement of glass fibers, carbon fibers, metal whiskers, etc. Agents, other additives or mixtures thereof.

The method for producing the thermoplastic resin composition of the present invention is not particularly limited, and a known method can be used. For example, after uniformly mixing the raw materials using a high-speed stirrer such as a tumbler or a Henschel mixer, a general kneader such as a Banbury mixer, a single-screw extruder, a twin-screw extruder, a coneder, or a multi-screw extruder is used. It can be obtained by a generally known method such as melting and kneading. It is also possible to knead a part of the raw material in advance and knead the remaining raw material in two stages. Further, the obtained thermoplastic composition can be obtained by any known molding method, for example, extrusion molding, injection molding,
By hollow molding, chemical foaming, physical foaming, etc., sheets, foams, films, injection molded products of various shapes, hollow molded products,
It can be formed into various types of products such as compressed air molded products, vacuum molded products, and vacuum compressed air molded products.

[0022]

The embodiments of the present invention will be specifically described below by way of examples. The resins used in the examples are as follows. (A) Styrene resin (HIPS): Production of rubber-modified styrene resin Polybutadiene [(cis 1,4 bond / trans 1,4 bond / vinyl 1,2 bond weight ratio = 95/2/3) (Zeon Corporation) ) Made, brand name Nipol / 1220SL)]
Was dissolved in the following mixture to give a uniform solution. Polybutadiene 10.5 wt% Styrene 74.2 wt% Ethylbenzene 15.0 wt% α-methylstyrene dimer 0.27 wt% t-butylperoxyisopropyl carbonate 0.03 wt%

Next, the above mixed solution is continuously fed to a serial 4-stage reactor equipped with a stirrer, and the stirring speed of the first to fourth stage reactors is increased to 190 to 20 rpm and the temperature is set to 126 to 155 ° C. The polymerization solution was further introduced into a deaerator to remove unreacted monomers and solvent. The rubber content was 12.1% by weight, the weight average particle size of the rubber was 1.5 μm, and the reduced viscosity μsp / c was 0.1%. 79
dl / g of a rubber-modified styrene resin was obtained. (GP-1): Stylon 683 (manufactured by Asahi Kasei Corporation) non-rubber-modified styrene resin MFR = 3.0 g / 10 min. (ISO R1113, 200 ° C. × 5 kg) (GP-2): Styrone 685 (manufactured by Asahi Kasei Corporation) non-rubber-modified styrene resin MFR = 2.1 g / 10 min. (Same conditions as above) (CP-1): Styrone G9001 (manufactured by Asahi Kasei Corporation) Styrene-methacrylic acid copolymer

(B) Propylene resin (PP-1): Jiaomer E610G (manufactured by Nippon Polyolefin) Propylene-ethylene block copolymer MFR = 0.5 g / 10 min. (JIS K6758, 230 ° C x 2.16 kg) (PP-2): J-Aroma PB270A (manufactured by Nippon Polyolefin) Propylene-ethylene block copolymer MFR = 0.75 g / 10 min. (Same conditions as above)

(C) Ethylene-α-olefin copolymer
Rubber In the examples, component (C), ethylene-α-olefin
The following copolymer rubber was used. Also, GPC
The measurement conditions are shown. (C-1): ENGAGE 8400 (Dupont Doue
Comonomer: Octene-1 Comonomer content: 24.0% by weight Density: 0.870 g / cm^Three  Mw / Mn = 2.6 MFR = 30 (ATSM-D1238, 190 ° C. × 2.16)
kg) (C-2): ENGAGE 8200 (Dupont Doue
Comonomer: Octene-1 Comonomer content: 24.0% by weight Density: 0.870 g / cm^Three  Mw / Mn = 2.4 MFR = 1.0 (same conditions as above)

(GPC measurement conditions): Apparatus: Waters 150C GPC 2. 2. Column: SHODEX AT-807S 1 Tosoh TSK-GEL GMH-H6 2 3 in total Solvent: 1,2,4-trichlorobenzene Measurement temperature: 140 ° C5. Standard substance: polystyrene (D) Styrene block copolymer rubber (D-1): Tuftec H1081 (manufactured by Asahi Kasei Corporation) Hydrogenated styrene-butadiene block copolymer rubber

[0027]

Examples 1 to 6 and Comparative Examples 1 to 3 The components shown in Table 1 were mixed at the ratios shown in Table 1, and the cylinder temperature was 200 to 24.
After melt-kneading with a twin-screw extruder set at 0 ° C., the mixture was pelletized to obtain resin composition pellets. Thereafter, each test piece was molded by injection molding, and the following evaluation was performed using the obtained test piece. Table 1 shows the results. (1) Melt flow rate (MFR): ISO R11
33, 200 ° C x 5 kg (2) IZOD impact strength: ASTM-D256, 1/4
(3) Tensile strength, elongation: ASTM-D638 (4) Flexural strength, flexural modulus: ASTM-D790 (5) Vicat softening temperature: ASTM-D1525 (6) Degree of peeling: Tensile strength measurement test After the test, the fracture surface of the test piece was visually observed and judged. ○ No peeling was observed. △ Peeling is observed. × Large enough for peeling.

[0028]

[Table 1]

[0029]

Examples 7 and 8, Comparative Example 4 From the resin compositions obtained in Examples 3 and 5, and the components and quantitative ratios shown in Table 2, Examples 1 to 6 were used.
Using a resin extruder set at a cylinder temperature of 200 to 240 ° C., a sheet having a thickness of 0.3 mm was formed using the resin composition of Comparative Example 4 obtained in the same manner as in Example 1. This sheet is vacuum formed to have an opening of 70 × 70 mm and a bottom of 50 × 5.
A rectangular container having a depth of 0 mm and a depth of 50 mm was formed. 10 g of coconut oil was put in this container, and it was put in an oven at the temperature setting shown in Table 2 while holding it at the brim at the top of the container and keeping the bottom floating, and the state change was observed. Table 2 shows the results.

[0030]

[Table 2]

[0031]

Example 9 A styrene resin excluding a polypropylene resin, an ethylene-α-olefin copolymer rubber, and a styrene block copolymer rubber shown in Table 3 were mixed at a ratio shown in Table 3. After melt-kneading with a twin-screw extruder set at a cylinder temperature of 200 to 240 ° C., the mixture was pelletized to obtain pre-blend pellets. The pre-blended pellet and the polypropylene-based resin are mixed with the pre-blended pellet 80 at a weight ratio of the polypropylene-based resin of 30 and melt-kneaded in a single screw extruder set at a cylinder temperature of 200 to 240 ° C, and then pelletized to form a resin. A composition pellet was obtained. This was evaluated in the same manner as in Examples 1 to 6, and the results are shown in Table 3.

[0032]

[Table 3]

As shown in Examples, a thermoplastic resin composition comprising a styrene resin and a polypropylene resin contains a specific ethylene-α-olefin copolymer rubber,
Only when styrene and a styrene-based block copolymer rubber are used together, practically compatible compatibility and excellent physical property balance can be achieved.

[0034]

The thermoplastic resin composition comprising a styrene resin and a polypropylene resin according to the present invention has good compatibility, and has heat resistance, oil resistance, chemical resistance, impact resistance, rigidity,
Because of its excellent tensile strength, it is possible to easily obtain molded articles most suitable for food containers, extruded sheets for food containers, general home appliances, various industrial parts, general household goods, and the like. This effect is achieved only when a specific ethylene-α-olefin copolymer rubber and a styrene block copolymer rubber are used in combination.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 BB053 BB123 BB142 BB152 BB153 BC031 BC041 BC061 BC071 BC081 BC091 BC111 BK001 BN021 BN141 BP011 BP014 BP022 FD010 FD090 FD160 FD170 GC00 GG01 GQ00

Claims (3)

[Claims] 1. A gel (C) based on a total of 100 parts by weight of (A) 50 to 95 parts by weight of a styrene resin, (B) 50 to 5 parts by weight of a propylene resin, and (A) + (B). The molecular weight distribution (Mw / Mn), which is the ratio between the weight average molecular weight (Mw) and the number average molecular weight (Mn), calculated by permeation chromatography (GPC) is 4.
A thermoplastic resin containing 0.1 to 25% by weight of an ethylene-α-olefin copolymer rubber and (D) 0.1 to 25% by weight of a styrene block copolymer rubber, which is less than 0 Composition. 2. The thermoplastic resin composition according to claim 1, wherein the ethylene-α-olefin copolymer rubber (C) is ethylene-octene-1. 3. Styrene block copolymer rubber (D)
Is a hydrogenated product of a styrene butadiene block copolymer. The thermoplastic resin composition according to claim 1 or 2, wherein