JP5070714B2 - Polypropylene resin composition and injection molded body thereof - Google Patents

Description

  The present invention relates to a polypropylene resin composition and an injection molded body thereof. More specifically, the present invention relates to a polypropylene resin composition excellent in heat resistance, Rockwell hardness and ductility, and an injection molded product thereof.

  Polypropylene resin compositions have been conventionally used in various molded products and the like because of their excellent rigidity, impact resistance, and heat resistance. For example, JP 2000-72938 A discloses a nucleating agent as a polyolefin resin composition used for a sheet and a molded article made of the sheet, with respect to a polypropylene resin having a certain degree of crystallinity and a specific range of MFR. And a polyolefin resin composition containing a polyethylene resin having a temperature rise elution fractionation characteristic, density, and MFR of a certain level or more.

JP 2000-72938 A

  However, with respect to the polyolefin resin composition described in the above publication, further improvements in heat resistance, Rockwell hardness and ductility have been desired. Under such circumstances, an object of the present invention is to provide a polypropylene resin composition excellent in heat resistance, Rockwell hardness and ductility, and an injection-molded body comprising the same.

As a result of studies, the present inventors have found that the present invention can solve the above problems, and have completed the present invention.
That is, the present invention
Resin mixture (I) containing the following polypropylene resin (component (A)) 86-95 wt% and the following polyethylene resin (component (B)) 5-14 wt% (component (A) and component (B) A polypropylene resin composition containing 0.03 to 2 parts by weight of a nucleating agent (component (C)) with respect to 100 parts by weight of the resin mixture (I) and injection molding thereof It relates to the body.
Ingredient (A):
Propylene containing a propylene homopolymer or a structural unit of 1 mol% or less derived from at least one olefin selected from the group consisting of ethylene and an α-olefin having 4 to 20 carbon atoms and a structural unit derived from propylene A copolymer (provided that the total amount of propylene copolymer is 100 mol%),
A polypropylene resin having a melt flow rate (JIS-K6758) measured at a measurement temperature of 230 ° C. and a load of 2.16 kgf of 15 to 50 g / 10 min .
Ingredient (B):
A copolymer of ethylene with at least one olefin selected from propylene and an α-olefin having 4 to 20 carbon atoms,
The density is 0.885 to 0.850 g / cm ³ ;
A polyethylene resin having a melt flow rate (JIS-K7210) measured at a measurement temperature of 190 ° C. and a load of 2.16 kgf of 1 to 50 g / 10 min.

  According to the present invention, it is possible to obtain a polypropylene resin composition excellent in heat resistance, Rockwell hardness and ductility, and an injection molded body thereof.

  The polypropylene resin (component (A)) used in the present invention is 1 mol% derived from a propylene homopolymer or at least one olefin selected from the group consisting of ethylene and an α-olefin having 4 to 20 carbon atoms. It is a propylene copolymer containing the following structural units and structural units derived from propylene (however, the total amount of the propylene copolymer is 100 mol%).

  Examples of the α-olefin having 4 to 20 carbon atoms used for the component (A) include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-pentene-1, 4 -Methyl-hexene-1,4,4-dimethyl-pentene-1 and the like are mentioned, and 1-butene is preferred. These α-olefins may be used alone or in combination of at least two.

  When component (A) is a propylene copolymer, it is a structural unit derived from at least one olefin selected from the group consisting of ethylene and an α-olefin having 4 to 20 carbon atoms contained in the propylene copolymer. Content is 1 mol% or less. When the content of the structural unit derived from the content of the structural unit derived from olefin exceeds 1 mol%, the heat resistance and hardness may be insufficient.

The melt flow rate (hereinafter referred to as MFR) (JIS-K6758) measured at a measurement temperature of 230 ° C. and a load of 2.16 kgf of component (A) is 15 to 50 g / 10 minutes. When the MFR of the component (A) is less than 2 g / 10 minutes, the moldability may be insufficient, and when it exceeds 90 g / 10 minutes, the ductility may be insufficient.

From the viewpoint of heat resistance or hardness, the component (A) of the present invention is preferably a propylene homopolymer, more preferably an isotactic pentad fraction measured by ¹³ C-NMR of 0.95 or more. It is a certain propylene homopolymer.

The isotactic pentad fraction is defined as the method published by A. Zambelli et al., Macromolecules, 6,925 (1973), i.e., the isoform of pentad units in a polypropylene molecular chain measured using ¹³ C-NMR. It is the fraction of the propylene monomer unit at the center of the tactic chain, in other words, the chain in which 5 propylene monomer units are continuously meso-bonded (however, the attribution of the NMR absorption peak is Macromolecules, 8,687 ( 1975)). Specifically, the isotactic pentad fraction was measured as the area fraction of the mmmm peak in the total absorption peak in the methyl carbon region of the ¹³ C-NMR spectrum. The isotactic pentad fraction of NPL standard substance CRM No. M19-14 Polypropylene PP / MWD / 2 of NATIONAL PHYSICAL LABORATORY, UK was measured by this method and found to be 0.944.

  The manufacturing method of a component (A) is a method of manufacturing by the conventional polymerization method using the conventional polymerization catalyst. Examples of the polymerization catalyst used in the production of component (A) include (a) a solid catalyst component containing magnesium, titanium, halogen and an electron donor as essential components, (b) an organoaluminum compound, and (c) electron donation. And catalyst systems formed from body components. The production method of this catalyst is described in, for example, JP-A-1-319508, JP-A-7-216017, JP-A-10-212319, and the like.

  Examples of the polymerization method used for producing the component (A) include bulk polymerization, solution polymerization, slurry polymerization, and gas phase polymerization. These polymerization methods may be either batch type or continuous type, and these polymerization methods may be arbitrarily combined. From the industrial and economical viewpoint, the gas phase polymerization method is preferred.

  In the production of the component (A), the amount of the solid catalyst component (a), the organoaluminum compound (b), and the electron donor component (c) used, and the method of supplying each catalyst component to the polymerization tank are known catalysts. What is necessary is just to determine suitably according to a usage method.

  In manufacture of a component (A), superposition | polymerization temperature is -30-300 degreeC normally, Preferably it is 20-180 degreeC. The polymerization pressure is usually normal pressure to 10 MPa, preferably 0.2 to 5 MPa. As the molecular weight regulator, for example, hydrogen can be used.

  In the production of the component (A), preliminary polymerization may be performed by a known method before the polymerization (main polymerization). As a known prepolymerization method, for example, a method of supplying a small amount of propylene in the presence of the solid catalyst component (a) and the organoaluminum compound (b) and carrying out in a slurry state using a solvent can be mentioned.

  The polyethylene resin (component (B)) used in the present invention is a copolymer of ethylene with at least one olefin selected from propylene and an α-olefin having 4 to 20 carbon atoms. Examples of the α-olefin having 4 to 20 carbon atoms used for the component (B) include the same α-olefin as the α-olefin having 4 to 20 carbon atoms used for the component (A), and preferably 1 -Butene, 1-hexene, 1-octene.

The density of component (B) is 0.885 to 0.850 g / cm ³ . When the density of the component (B) is less than 0.85 g / cm ³ , the rigidity may be insufficient, and when it exceeds 0.885 g / cm ³ , the impact strength may be insufficient.

  The melt flow rate (hereinafter referred to as MFR) (JIS-K7210) measured at a measurement temperature of 190 ° C. and a load of 2.16 kgf of component (B) is 1 to 50 g / 10 minutes, preferably 2 to 30 g / 10 minutes. It is. When the MFR of the component (B) is less than 1 g / 10 minutes, the moldability may be insufficient, and when it exceeds 50 g / 10 minutes, the impact strength may be insufficient.

The manufacturing method of a component (B) is a method of manufacturing with the conventional polymerization method using the conventional polymerization catalyst. Examples of the polymerization catalyst used for the production of the component (B) include a Ziegler type catalyst (a catalyst comprising a combination of a supported or non-supported halogen-containing titanium compound and an organoaluminum compound), a Philips type catalyst (supported oxidation). chromium (Cr ⁶⁺⁾ consists catalyst), Kaminsky type catalyst (supported or unsupported metallocene compound and an organoaluminum compound (in particular, alumoxanes) a combination of a catalyst) and the like. As the component (B), a polyethylene resin having a relatively narrow composition distribution is desirable. Therefore, the catalyst is preferably a Kaminsky catalyst.

  As a polymerization method used for the production of the component (B), a slurry polymerization method, a gas phase fluidized bed polymerization method (for example, a method described in JP-A-59-23011), a solution polymerization method, and a pressure of 20 MPa or more. And a high-pressure bulk polymerization method performed at a polymerization temperature of 100 ° C. or higher. Further, for example, the molecular weight and the crystallinity distribution can be controlled by adjusting the polymerization temperature and the monomer amount by a known method.

  The nucleating agent (component (C)) used in the present invention is a substance having a nucleating effect on polypropylene resin, such as 1,3: 2,4-bis (o-benzylidene) sorbitol, 3: 2,4-bis (o-methylbenzylidene) sorbitol, 1,3: 2,4-bis (o-ethylbenzylidene) sorbitol, 1,3-o-3,4-dimethylbenzylidene-2,4-o -Benzylidene sorbitol, 1,3-o-benzylidene-2,4-o-3,4-dimethylbenzylidene sorbitol, 1,3: 2,4-bis (o-3,4-dimethylbenzylidene) sorbitol, 1,3 -Op-chlorobenzylidene-2,4-o-3,4-dimethylbenzylidene sorbitol, 1,3-o-3,4-dimethylbenzylidene-2,4-op-chlorobenzyl Densorbitol, 1,3: 2,4-bis (op-chlorobenzylidene) sorbitol, sodium bis (pt-butylphenyl) phosphate, sodium methylene (2,4-tert-butylphenyl) phosphate, Sodium-2,2-methylenebis (4,6-di-t-butylphenyl) phosphate, polyvinylcyclohexane, aluminum-di-para-tertiarybutyl-hydroxybenzoic acid, and the like, preferably aluminum-di- Para-tert-butyl-hydroxybenzoic acid. These nucleating agents may be used alone or in combination of at least two kinds.

  Content of the component (A) contained in the polypropylene resin composition of this invention is 86 to 95 weight%, Preferably it is 86 to 90 weight%. Content of a component (B) is 5-14 weight%, Preferably it is 10-14 weight%. However, the total of component (A) and component (B) is 100% by weight, and the resin mixture containing component (A) and component (B) is referred to as resin mixture (I). When the content of the component (A) is less than 86% by weight (that is, when the content of the component (B) exceeds 14% by weight), the heat resistance and Rockwell hardness may be insufficient. When the content of A) exceeds 95% by weight (that is, when the content of component (B) is less than 5% by weight), the impact strength may be insufficient.

  Content of a component (C) is 0.03 to 2 weight part with respect to 100 weight part of said resin mixture (I) containing a component (A) and a component (B), Preferably it is 0.03. 0.5 parts by weight. When the content of the component (C) is less than 0.03 parts by weight, the heat resistance and Rockwell hardness may be insufficient, and when it exceeds 2 parts by weight, the excess is uneconomical. May cause smoke and odor when injection molding.

  The melt flow rate (MFR) of the polypropylene resin composition of the present invention is preferably 5 to 120 g / 10 minutes, more preferably 8 to 50 g / 10, from the viewpoint of improving moldability, ductility and impact resistance. Minutes. The melt flow rate (MFR) of the polypropylene resin composition is a melt flow rate (JIS-K6758) measured at a measurement temperature of 230 ° C. and a load of 2.16 kgf.

  Methods for adjusting the melt flow rate of the polypropylene resin composition of the present invention include polypropylene resin (component (A)), polyethylene resin (component (B)), nucleating agent (component (C)), and organic peroxide. (Component (D)) and the method of melt-kneading are mentioned. The amount of the component (D) used is preferably 100 parts by weight of the resin mixture (I) containing the component (A) and the component (B) from the viewpoint of improving the melt flow rate adjusting effect and moldability. 0.001 to 0.1 parts by weight.

  Examples of the organic peroxide (component (D)) include alkyl peroxides, diacyl peroxides, peroxide esters, and carbonate carbonates. Examples of alkyl peroxides include dicumyl peroxide, di-t-butyl peroxide, di-t-butylcumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane. 2,5-dimethyl-2,5-di- (t-butylperoxy) hexene, 1,3-bis (t-butylperoxyisopropyl) benzene, 3,6,9-triethyl-3,6, Examples thereof include 9-trimethyl-1,4,7-tripperoxynonane.

  Examples of the diacyl peroxide include benzoyl peroxide, lauroyl peroxide, and decanoyl peroxide. Examples of the peroxide ester include 1,1,3,3-tetramethylbutylperoxyneodecanate. , T-butyl peroxyneodecanate, α-cumyl peroxyneodecanate, t-butyl neoheptanoate, t-butyl peroxypivalate, t-hexyl peroxypivalate, 1,1,3,3- Tetramethylbutylperoxy-2-ethylhexanate, t-amylperoxy-2-ethylhexanate, t-butylperoxyisobutyrate, di-t-butylperoxyhexahydroterephthalate, t-amylperoxy- 3,5,5-trimethylhexanate, t-butylperoxya Tate, t- butyl peroxybenzoate and di -t- butyl peroxy trimethyl adipate Tate and the like.

  Examples of the peroxide carbonates include di-3-methoxybutyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, diisopropyl peroxycarbonate, t-butylperoxyisopropyl carbonate, and di (4-t- Butylcyclohexyl) peroxydicarbonate, dicetylperoxydicarbonate, dimyristylperoxydicarbonate, and the like.

  The organic peroxide (component (D)) is preferably alkyl peroxides, more preferably 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 1,3-bis. (T-Butylperoxyisopropyl) benzene, 3,6,9-triethyl-3,6,9-trimethyl-1,4-7-triperoxynonane.

  The method for producing the polypropylene resin composition of the present invention is an ordinary melt-kneading method, and examples thereof include a method using a single screw extruder, a twin screw extruder, a Banbury mixer, a hot roll, a brabender, a kneader and the like.

  You may add various additives to the polypropylene resin composition of this invention as needed. Examples of the additive include an antioxidant, an ultraviolet absorber, a lubricant, a pigment, an antistatic agent, a copper damage inhibitor, a flame retardant, a neutralizing agent, a foaming agent, a plasticizer, an anti-bubble agent, and a crosslinking agent. It is done.

  The injection molded product of the present invention is composed of the polypropylene resin composition of the present invention. The injection molding method includes a known injection molding method.

  Hereinafter, the present invention will be described by way of examples. The measuring method of the physical property of the polymer used in the Example and the comparative example and the composition was shown below.

(1) Melt flow rate (MFR, unit: g / 10 minutes)
(1-1) Measurement of MFR of polypropylene resin Measurement was performed according to JIS-K6758 at a measurement temperature of 230 ° C. and a load of 2.16 kgf.
(1-2) Measurement of MFR of polyethylene resin Measurement was performed according to JIS-K7210 at a measurement temperature of 190 ° C. and a load of 2.16 kgf.

(2) Heat resistance test (heat distortion temperature (HDT), unit: ° C)
It measured according to the method prescribed | regulated to JIS-K-7207. Using a test piece having a thickness of 6.4 mm and a span length of 100 mm, which was formed by the method for producing an injection-molded body described later, the fiber stress was measured at 4.6 kg / cm ² .

(3) Rockwell hardness (R scale)
It measured according to the method prescribed | regulated to JIS-K-7202. It measured using the test piece which was shape | molded by the manufacturing method of the injection molding body mentioned later and whose thickness is 5.0 mm. The measured value was displayed on the R scale.

(4) Tensile test (elongation at break (UE), unit:%)
The measurement was performed according to the method specified in ASTM D638. It measured using the test piece which was shape | molded by the manufacturing method of the injection molding body mentioned later and which is 3.2 mm. Measurement was performed at a pulling speed of 50 mm / min.

[Method for producing injection-molded article]
The test pieces which are the injection molded articles for evaluating physical properties of the above (2) to (4) were produced according to the following method. Using a Nestal Cycap 120t injection molding machine manufactured by Sumitomo Heavy Industries, injection molding was performed at a molding temperature of 220 ° C., a mold cooling temperature of 50 ° C., and a cooling time of 20 seconds to obtain a test piece which was an injection molded body.

Example 1
Component (A): propylene homopolymer (MFR: 19 g / 10 min) 86 parts by weight Aluminum (di-para-tertiarybutyl-hydroxybenzoic acid) (trade name, manufactured by Dainippon Ink Co., Ltd.) Copolymer with 0.05 parts by weight of Al-PTBBA) and butene based on ethylene as the component (B) (manufactured by Sumitomo Chemical Co., Ltd., trade name EXCELEN FX CX5505, MFR: 16 g / 10 min, density: A melt-kneaded product to which 14 parts by weight of 0.868 g / cm ³ ) was added was obtained.

  With respect to this melt-kneaded product, a test piece was molded according to the above-described method, and physical properties were evaluated. The results are shown in Table 1. The test piece was excellent in the balance of heat resistance, Rockwell hardness, and elongation at break, and particularly excellent in heat resistance and elongation at break.

Example 2
A melt-kneaded material was obtained in exactly the same manner as in Example 1, except that the blending ratios of the component (A) and the component (B) were changed to 90% by weight and 10% by weight, respectively. As shown in Table 1, the molding / evaluation results were excellent in all of heat resistance, Rockwell hardness, and elongation at break.

Example 3
In Example 1, the blending ratio of component (A) and component (B) was changed to 87% by weight and 13% by weight, respectively, and a copolymer (butane) with butene containing ethylene as a main component as component (B). DuPont Elastomer Co., Ltd., trade name Engage ENR7447, MFR: 5.0 g / 10 min, density: 0.864 g / cm ³ ) Except for the addition of 13 parts by weight, a melt-kneaded material was obtained in the same manner as in Example 1. It was. As shown in Table 1, the molding / evaluation results were excellent in all of heat resistance, Rockwell hardness, and elongation at break.

Comparative Example 1
In Example 3, copolymer of butene whose component (B) is ethylene as a main component (manufactured by Sumitomo Chemical Co., Ltd., trade name Espren SPO N0377, MFR: 18 g / 10 min, density: 0.890 g / cm ³ The melt-kneaded material was obtained in exactly the same manner as in Example 3 except that the above was changed. As shown in Table 1, the results of molding and evaluation were inferior in heat resistance as compared with Examples 1 to 3.

Comparative Example 2
In Example 3, copolymer of butene whose component (B) is ethylene as a main component (manufactured by Sumitomo Chemical Co., Ltd., trade name: EXCELEN VL VL800, MFR: 20 g / 10 min, density: 0.905 g / cm ³ The melt-kneaded material was obtained in exactly the same manner as in Example 3 except that the above was changed. As shown in Table 1, the results of molding and evaluation were inferior in heat resistance as compared with Examples 1 to 3.

Comparative Example 3
As component (A), 100 parts by weight of propylene homopolymer (MFR: 19 g / 10 min) and 2,2 methylenebis (2,6-di-tert-butylphenyl) sodium phosphate (Asahi Denka Co., Ltd.) as component (C) A melt-kneaded product to which 0.3 part by weight of a product name, NA-11UY) was added was obtained. As shown in Table 1, the results of molding / evaluation were excellent in heat resistance and Rockwell hardness, but the elongation at break was significantly inferior to Examples 1 to 3.

Comparative Example 4
In Comparative Example 1, melted in exactly the same manner as in Comparative Example 1, except that the propylene-ethylene random copolymer (MFR: 20 g / 10 min) containing 2.5% by weight of ethylene was used with component (A) as a comonomer. A kneaded product was obtained. As shown in Table 1, the results of molding and evaluation were inferior in heat resistance.

Claims (3)

86-95% by weight of the following polypropylene resin (component (A)),
Resin mixture (I) containing 5 to 14% by weight of the following polyethylene resin (component (B)) (the total of component (A) and component (B) is 100% by weight), the resin mixture (I) A polypropylene resin composition containing 0.03 to 2 parts by weight of a nucleating agent (component (C)) with respect to 100 parts by weight.
Ingredient (A):
Propylene containing a propylene homopolymer or a structural unit of 1 mol% or less derived from at least one olefin selected from the group consisting of ethylene and an α-olefin having 4 to 20 carbon atoms and a structural unit derived from propylene A copolymer (provided that the total amount of propylene copolymer is 100 mol%),
A polypropylene resin having a melt flow rate (JIS-K6758) measured at a measurement temperature of 230 ° C. and a load of 2.16 kgf of 15 to 50 g / 10 min .
Ingredient (B):
A copolymer of ethylene with at least one olefin selected from propylene and an α-olefin having 4 to 20 carbon atoms,
The density is 0.885 to 0.850 g / cm ³ ;
A polyethylene resin having a melt flow rate (JIS-K7210) measured at a measurement temperature of 190 ° C. and a load of 2.16 kgf of 1 to 50 g / 10 min.   The polypropylene resin composition according to claim 1, wherein the melt flow rate (JIS-K6758) measured at a measurement temperature of 230 ° C and a load of 2.16 kgf is 5 to 120 g / 10 minutes.   An injection-molded article comprising the polypropylene resin composition according to claim 1 or 2.