4-methyl-1-pentene polymer compositions

Abstract: In accordance with the present invention, there are provided 4-methyl-1-pentene polymer compositions comprising 90-10 parts by weight of 4-methyl-1-pentene polymer (A) 90-10 parts by weight of propylene polymer (B) and 70-10 parts by weight of inorganic filler (C), provided that the sum of (A), (B) and (C) total to 100 parts by weight. There are also provided 4-methyl-1-­ pentene polymer compositions comprising 20-3 parts by weight of α-olefin copolymer (D) in addition to the above-­ mentioned components (A), (B) and (C), provided that the sum of (A), (B), (C) and (D) totals to 100 parts by weight. These compositions as illustrated above are capable of vacuum forming, injection blow-forming and the like, and they are excellent in rigidity at high temperatures, toughness at low temperatures and impact strength.

Description: FIELD OF THE INVENTION This invention relates to 4-methyl-1-pentene polymer compositions and more particularly to 4-methyl-1-pentene polymer compositions excellent in rigidity at high temperatures, toughness at low temperatures, thermoformability such as vacuum formability, surface hardness impact strength and the like properties. BACKGROUND OF THE INVENTION It is well known that when polyolefin such as polyethylene or polypropylene is incorporated with inorganic fillers such as calcium carbonate, barium sulfate and talc, the thus incorporated polyolefin is improved in rigidity. On one hand, 4-methyl-1-pentene polymer which is a kind of polyolefin is excellent in heat resistance, chemical resistance, transparency, mold release characteristics, etc., as compared with other polyolefins, but from the viewpoint of molecular structure there was such a problem that because of its low melt tension, the polymer is difficult to thermoform. Further, there was another problem that the incorporation into 4-methyl-1-pentene polymer of such inorganic fillers as mentioned above results in improved rigidity at high temperatures, but the toughness at low temperatures of the polymer thus incorporated comes to decrease thereby. DE-3307946-A1 discloses a composition for use as a diaphragm material for loudspeakers comprising a 4-methylpentene homopolymer a homopolymer of another α-olefin and a reinforcement of the key material, which composition is said to have improved film forming and thermal moulding characteristics. The present invention seeks to solve the problems associated with the prior art and to provide 4-methyl-1-pentene polymer compositions having excellent thermoformability, for example, by means of, for example, vacuum forming or injection blow molding, and having excellent rigidity at high temperature, toughness at low temperature and impact strength. The 4-methyl-1-pentene polymer composition of the present invention comprises 10 to 70 parts by weight of 4-methyl-1-pentene polymer (A), 10 to 70 parts by weight of propylene polymer (B), 10 to 70 parts by weight of inorganic filler (C) and 20-3 parts by weight of α-olefin copolymer (D) which is a random copolymer of at least 2 kinds of α-olefins, said random copolymer having a melt index of 0.1-50 g/10 min, a density of 0.850-0.900 g/cm³ and a crystallinity index as measured by X-ray of less than 40%. Because of their components as defined above, the 4-methyl-1-pentene polymer compositions are excellent in thermoformability, rigidity at high temperatures, toughness at low temperatures, impact strength and the like properties. DETAILED DESCRIPTION OF THE INVENTION The components of the 4-methyl-1-pentene polymer compositions of the present invention are illustrated below in detail. The 4-methyl-1-pentene polymer (A) used in the present invention is usually crystalline resin and includes a homopolymer of 4-methyl-1-pentene or copolymers of methyl-1-pentene and other α-olefins of 2-20 carbon atoms, for example, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-tetradecene, 1-octadecene, etc., said copolymers usually being polymers consisting essentially of 4-methyl-1-pentene in an amount of at least 85 mol%. Usually, this 4-methyl-1-pentene polymer (A) has a melt flow rate (MFR) measured by ASTM D 1238 (temperature: 260° C, load:5kg) of 0.05-500 g/10 min, though this rate may be varied according to the purpose for which the composition containing this polymer is used. The propylene polymer (B) used in the present invention is usually a crystalline resin and includes a homopolymer of propylene or copolymers of propylene and less than 30% by weight of at least one other α-olefin having 2-20 carbon atoms, for example, ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, etc. or terpolymers of propylene, ethylene and less than 5% by weight of a polyene component, for example, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene or 1,4-hexadiene. Usually, this propylene polymer (B) has a melting point of at least 130°C and a MFR of 0.1-80 g/10 min (ASTM D 1238 L). The inorganic filler (C) used in the present invention includes inorganic substances such as calcium carbonate, magnesium carbonate, hydrous basic magnesium carbonate, kaolin clay, pyrophylite, talc, calcined clay, diatomaceous earth, barium sulfate, etc. Of these inorganic substances, particularly preferred is talc. The α-olefin copolymer (D) used in the present invention is a random copolymer of at least two kinds of α-olefins. This α-olefin copolymer has a crystallinity index as measured by X-ray of less than 40%, preferably 1-30%, and is amorphous or low crystalline. This α-olefin copolymer (D) has a melt index or melt flow rate of 0.1-50 g/10 min, preferably 2-8 g/10 min (ASTM D 1238 E), a density of 0.850-0.900 g/cm³, preferably 0.875-0.895 g/cm³ and preferably has a melting point of 40-130°C, more preferably 60-80°C. Concretely speaking, this α-olefin copolymer (D) is composed of at least two kinds of α-olefins selected from α-olefins of 2-20 carbon atoms such as ethylene, propylene, 1-butene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Random copolymers of such α-olefins as mentioned above include concretely ethylene/propylene copolymers, ethylene/1-butene copolymers, ethylene/1-hexene copolymers, ethylene/1-octene copolymers, ethylene/1-decene copolymers, ethylene/1-hexadecene copolymers, propylene/1-butene copolymers, propylene/1-hexene copolymers, propylene/1-octene copolymers, propylene/1-decene copolymers, 1-butene/1-octene copolymers, 1-hexene/1-octene copolymers, ethylene/propylene/1-hexene copolymers, ethylene/1-butene/1-hexene copolymers, etc. In the 4-methyl-1-pentene polymer compositions of the present invention, there are present the 4-methyl-1-pentene polymer (A) in an amount of 70-10, preferably 70-30 parts by weight, the propylene polymer (B) in an amount of 70-10, preferably 70-30 parts by weight, the inorganic filler (C) in an amount of 70-10, preferably 50-30 parts by weight, and the α-olefin copolymer (D) in an amount of 20-3, preferably 15-5 parts by weight, provided that the sum of (A), (B), (C) and (D) totals to 100 parts by weight. In preparing the 4-methyl-1-pentene polymer composition of the present invention, the use of the 4-methyl-1-pentene polymer (A) in an amount of 70-10 parts by weight is selected, because the resulting composition becomes good in heat-resistant rigidity and impact strength. Similarly, the use of the propylene polymer (B) in an amount of 70-10 parts by weight is selected, because the resulting composition becomes tough and, is excellent in heat-resistant rigidity. The use of the inorganic filler (C) in an amount of 70-10 parts by weight is similarly selected, because the resulting composition becomes excellent in heat-resistance rigidity and, toughness. In preparing the 4-methyl-1-pentene polymer composition of the present invention, the use of the α-olefin copolymer (D) in an amount of 20-3 parts by weight improves impact strength and maintains a good heat-resistant rigidity. The 4-methyl-1-pentene polymer compositions of the present invention as illustrated above may be prepared by mixing, melt kneading, granulating or pulverizing a mixture comprising the 4-methyl-1-pentene polymer (A), propylene polymer (B), inorganic filler (C) and α-olefin copolymer (D) in the specific proportion as defined above by various known methods, for example, those using a V-blender, ribbon blender, Henschel mixer, tumbler blender, extruder, single-screw extruder, double-screw extruder, kneader or Banbury mixer. The 4-methyl-1-pentene polymer compositions of the present invention may be incorporated with various additives commonly added to polyolefin such as weathering agents, heat stabilizers, rust preventives, slip agents, nucleating agents, pigments, dyes or surfactants, in such an amount as will not hinder the object of the present invention. Because of their excellent rigidity at high temperature, toughness at low temperatures, thermoformability such as vacuum formability or surface hardness, the 4-methyl-1-pentene polymer compositions of the present invention are suitable for use in parts of household electrical appliances, tablewares for electron range cooking or industrial parts. The present invention is illustrated below in detail with reference to examples, but it should be construed that the invention is in no way limited to those examples. Comparative Example 1 Using a Henschel mixer, a mixture was prepared by mixing together 35 parts by weight of 4-methyl-1-pentene/1-decene crystalline copolymer (1-decene content: 3% by weight, melting point: 236°C, MFR: 26g/10min), 35 parts by weight of propylene/ethylene crystalline block copolymer (ethylene content: 20% by weight, density: 0.91g/cm³ MFR: 0.5g/10min), 30 parts by weight of talc (a product of Matsumura Sangyo, sold under a trade name Crown P-2), 0.25 part by weight of tetrakis [methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] methane (a product of Musashino-Geigy, sold under a trade name Iruganox 1010: hereinafter abbreviated to TPM), and 0.25 part by weight of stearic acid monoglyceride (a product of Kao Soap, sold under a trade name Atomos #150; hereinafter abbreviated to SMG). The resulting mixture was melt kneaded with a 40 mm⊘ extruder to obtain composition-I. With an injection molding machine (M-100 Type manufactured and sold by Meiki Seisakusho) operated at the molding temperature of 300°C and the mold temperature of 60°C, the composition-I thus obtained was then molded into a test specimen, 120 mm x 20 mm x 3 mm, for measuring heat deformation temperature (HDT), an ASTM TYPE IV specimen for tensile test, a test specimen for Izod impact test, and into a square sheet, 100 mm x 100 mm x 2 mm, for surface hardness test, respectively. These test specimens thus prepared were evaluated by the following procedures. Tensile test: Measurement was conducted in accordance with ASTM D638, provided that the ASTM TYPE IV specimen was used. Heat deformation temperature: Measurement was conducted in accordance with ASTM D648, provided that the load applied was 66 psi. Izod impact test: Measurement was conducted in accordance with ASTM D256. Surface hardness: Measurement was conducted in accordance with JIS K-5401. Separately, the composition-I was molded at a press temperature of 260°C and a press pressure of 80 kg/cm² into a film of 300 µm in thickness. The film thus obtained was co-biaxially oriented at 260°C, whereupon a biaxially oriented film of a draw ratio of 3 x 3 was obtained. The results obtained are shown in Table 1. Comparative Examples 2-4 Comparative Example 1 was repeated except that the amounts of the components used therein were changed to those as shown in Table 1. The results obtained are shown in Table 1. Comparative Examples 5-8 Comparative Example 1 was prepared except that the amounts of the components used therein were changed to those as shown in Table 1. The results obtained are shown in Table 1. Example 1 Using a Henschel mixer, a mixture was prepared by mixing together 35 parts by weight of 4-methyl-1-pentene /1-decene crystalline copolymer (1-decene content: 3% by weight, melting point: 236°C, MFR: 26g/10min), 30 parts by weight of propylene/ethylene crystalline block copolymer (ethylene content: 20% by weight, density: 0.91g/cc, MFR: 0.5g/10min), 30 parts by weight of talc (Crown P-2), 5 parts by weight of ethylene/1-butene random copolymer (ethylene content 80% by weight MFR (ASTM D 1238 E, 4g/10min), density 0.886g/cm³), 0.25 part by weight of tetrakis [methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] methane (TPM) and 0.25 part by weight of stearic acid monoglyceride (Atomos #150). The resulting mixture was melt kneaded with a 40 mm⊘ extruder to obtain composition-II. With an injection molding machine (M-100 Type of Meiki Seisakusho) operated at the molding temperature of 300°C and the mold temperature of 60°C, the composition-II thus obtained was then molded into a test specimen, 120 mm x 20 mm x 3 mm, measuring heat deformation temperature (HDT), an ASTM TYPE IV specimen for tensile test, a test specimen for Izod impact test, and into a square sheet, 100 mm x 100 mm x 2 mm, for surface hardness test, respectively. These test specimens thus prepared were evaluated by the same procedures as in Example 1. Separately, the composition-II was molded at a press temperature of 260°C and a press pressure of 80 kg/cm² into a film of 400 µm in thickness. The film thus obtained was co-biaxially oriented at 235°C, whereupon a biaxially oriented film of a draw ratio of 3 x 3 was obtained. The results obtained are shown in Table 2. Examples 2-4 Example 1 was repeated except that the amount of the components used therein were changed to those as shown in Table 2. The results obtained are shown in Table 2. Comparative Examples 9-11 Example 1 was repeated except that the amounts of the components used therein were changed to those as shown in Table 2. The results obtained are shown in Table 2. For reference's sake, the results obtained in Comparative Example 1 are shown also in Table 2.

Claims: A composition comprising 10 to 70 parts by weight of 4-methyl-1-pentene polymer (A), 10 to 70 parts by weight of a propylene polymer (B), 10 to 70 parts by weight of an inorganic filler (C) and 3 to 20 parts by weight of an α-olefin copolymer (D) which is a random copolymer of at least two kinds of α-olefins, said random copolymer having a melt flow rate of 0.1 to 50 g/10 min, a density of 0.850 to 0.900 g/cm³ and a crystallinity index as measured by X-ray of less than 40%, the sum of (A), (B), (C) and (D) totalling 100 parts by weight. A composition according to claim 1 wherein (A) is a homopolymer of 4-methyl-1-pentene or a copolymer of 4-methyl-1-pentene and at least one other α-olefin of 2 to 20 carbon atoms. A composition according to claim 1 or 2 wherein (B) is a homopolymer of propylene or a copolymer of propylene and at least one other α-olefin of 2 to 20 carbon atoms. A composition according to claim 1, 2, or 3 wherein (C) is calcium carbonate, magnesium carbonate, hydrous basic magnesium carbonate, kaolin clay, pyrophylite, talc, calcined clay, diatomaceous earth or barium sulfate. A composition according to claim 1, 2, 3, or 4 wherein (D) is an ethylene/propylene copolymer, ethylene/1-butene copolymer, ethylene/1-hexene copolymer, ethylene/1-octene copolymer, ethylene/1-hexadecene copolymer, propylene/1-butene copolymer, propylene/1-hexene copolymer, propylene/1-octene copolymer, propylene/1-decene copolymer, 1-butene/1-octene copolymer, ethylene/propylene/1-hexene copolymer or ethylene/1-butene/1-hexene copolymer. A composition according to any preceding claim which contains 30 to 70 parts by weight of (A). A composition according to any preceding claim which contains 30 to 70 parts by weight of (B). A composition according to any preceding claim which contains 30 to 50 parts by weight of (C). A composition according to any preceding claim which contain 5 to 15 parts by weight of (D). Shaped articles obtained by thermoforming a composition as claimed in any preceding claim.

Inventors: SHIGEMORI HIROMI, SHIGEMORI, HIROMI
Applicants: MITSUI PETROCHEMICAL IND, MITSUI PETROCHEMICAL INDUSTRIES, LTD.
Application year: 1988
Main classification: C08L23
IPC codes: C08K3, C08L23, C08L53