JPS6410006B2 - - Google Patents

Description

[Detailed description of the invention]

[I] Object of the invention The present invention relates to a resin composition. More specifically, (A) ethylene/propylene random copolymer, (B) (1) ethylene/propylene copolymer rubber, and
(2) At least one rubbery material selected from the group consisting of ethylene/propylene/diene ternary copolymer rubber; and (C) a linear copolymer of ethylene and α-olefin with short chain branches. The present invention relates to a resin composition and aims to provide a resin composition with excellent low-temperature impact resistance. [] Background of the Invention For some time now, compositions obtained by blending olefin-based synthetic resins mainly composed of olefins such as ethylene polymers and propylene polymers and/or synthetic rubbers have been used in a wide variety of fields. It's being used. These compositions have low-temperature impact resistance, moldability, surface gloss of molded products, heat resistance,
Although some of the physical properties such as tensile strength, surface hardness, and flexibility are excellent, it is difficult to say that the composition has satisfactory softness when judged comprehensively. In addition, in recent years, olefin-based thermoplastic elastomers (TP) have been developed as olefin-based soft resin compositions.
E) was developed, but it is not only expensive but also has the problem of poor surface gloss of the molded product. In addition, ethylene, propylene, and
Resin blends of block copolymers and high-density polyethylene (HDPE) or ethylene-vinyl acetate copolymers (EVA) have been proposed;
The compositions obtained by these methods have a problem of poor impact resistance at a considerably low temperature such as -60°C. [] Structure of the Invention Based on the above, the present inventors have conducted various searches in order to obtain a resin composition that is not only inexpensive but also has excellent low-temperature impact resistance. is 3 to 9% by weight, and the stiffness (measured based on ASTM D-747)
is 10000Kg/cm ² or less, and the melt flow index (based on JISK-6758, measured at a temperature of 230℃ and a load of 2.16Kg, hereinafter referred to as "MFI") is 0.5 to 20g/10 minutes. ``ethylene propylene random copolymer'' (hereinafter referred to as ``propylene copolymer''), (B) (1) ``ethylene propylene copolymer rubber'' (hereinafter referred to as ``EPR''), and (2) At least one rubber-like material selected from the group consisting of "ethylene-propylene-diene ternary copolymer rubber" (hereinafter referred to as "EPDM"), and (C) "Melt index (measured based on JIS K-6760)" , measured at a temperature of 190℃ and a load of 2.16Kg, hereinafter referred to as "MI") is 0.5 to 40g/10
A linear copolymer with short chain branches of ethylene and α-olefin having at most 12 carbon atoms and having a density of 0.910 to 0.925 g/cm ³ as measured in accordance with JIS K-6760. (hereinafter referred to as "ethylene-based linear copolymer"), and the total amount of the random copolymer and rubber-like material in the composition is 30 to 80% by weight, The blending ratio of the random copolymer in the total of the random copolymer and the rubbery material is 99~
The resin composition, which is characterized by a content of 50% by weight, not only has excellent low-temperature impact resistance, but also
It was discovered that it can be obtained at a relatively low price, and the present invention was achieved. [] Effects of the Invention The composition obtained by the present invention can not only be produced at a relatively low cost, but also has excellent physical properties as described below. (1) Excellent impact resistance at low temperatures (-60℃). (2) The surface of the molded product has good gloss and hardness. (3) Excellent heat resistance and flexibility. (4) Since moldability is good, molded products with complex shapes can be manufactured. (5) Low molding shrinkage and few sink marks. The appearance is also good. (6) It also has excellent weather resistance. The composition obtained by the present invention not only can be produced at a relatively low cost, but also has the above-mentioned good physical properties, so it is expected to be used in a wide variety of fields. However, typical uses are shown below. (1) Automotive parts such as bumper faces, bumper corners, bumper sight shields, and muzzle guard ducts; (2) Soft parts such as hoses, tubes, and grips [] Detailed description of the invention (A) Propylene copolymer The present invention The propylene copolymer used in is a random copolymer of ethylene and propylene. The content of ethylene in this propylene copolymer is 3 to 9% by weight, preferably 4 to 9% by weight, and particularly preferably 6 to 9% by weight. If the ethylene content is less than 3% by weight, the resulting composition will have poor flexibility. On the other hand, 9
Even if an attempt is made to produce a propylene-based copolymer in excess of this amount by weight, so-called fouling occurs during production, making it difficult to produce it in a satisfactory state. Further, the stiffness is 10,000 Kg/cm ² or less, preferably 8,000 Kg/cm ² or less, particularly preferably 5,000 Kg/cm ² or less. When the stiffness exceeds 10,000 Kg/cm ² , the flexibility of the resulting molded product decreases. Furthermore, the MFI of this propylene copolymer is 0.5 to 20 g/10 minutes, especially
1.0-10g/10 minutes is suitable. If the MFI of the propylene copolymer is less than 0.5 g/10 minutes, it is difficult to knead a homogeneous composition, and furthermore, the moldability of the composition is poor. On the other hand, if it exceeds 20g/10 minutes, impact resistance, especially low-temperature impact resistance, will be poor. (B) Rubber-like material Furthermore, the rubber-like material used in the present invention is
At least one rubber-like material selected from the group consisting of EPR and EPDM. EPR is obtained by copolymerizing ethylene and propylene. On the other hand, EPDM mainly consists of ethylene and propylene, including 1,4-pentadiene, 1,5-hexadiene and 3,
Linear or branched diolefins containing two double bonds at the ends, such as 3-dimethyl-1,5-hexadiene, and double bonds such as 1,4-hexadiene and 6-methyl-1,5-heptadiene. Linear or branched diolefin or bicyclo [2,2,
1] Multicomponent copolymer rubber obtained by copolymerizing a small amount of a monomer having a double bond such as a cyclic diene hydrocarbon such as -heptene-2 (norbornene) and its derivatives (for example, ethylidene norbornene) It is. this
EPR and EPDM preferably have a weight ratio of ethylene monomer units to propylene monomer units of 20/80 to 80/20. Further, the copolymerization ratio of the monomer having double bonds in EPDM is at most 10% by weight. These rubber-like materials are industrially produced and widely used with a catalyst system containing a transition metal compound and an organometallic compound (generally an organoaluminum compound) as main components. These rubbery materials preferably have a Mooney viscosity of 20 to 140, especially
30 to 120 is preferable. Also, MI
(Measured according to ASTM D-1238, temperature 190
℃, load 2.16Kg) is generally 0.1 to 6g/10 minutes. (C) Ethylene-based linear copolymer The ethylene-based linear copolymer used in the present invention is a copolymer of ethylene and α-olefin. MI of the ethylene-based linear copolymer
is 0.5 to 40 g/10 minutes, preferably 1.0 to 30 g/10 minutes, particularly preferably 4.0 to 20 g/10 minutes. If the MI of the ethylene-based linear copolymer is less than 0.5 g/10 minutes, moldability (especially injection molding) is poor. On the other hand, if it exceeds 40g/10 minutes, it is not preferable because impact resistance is low. The density of the ethylene-based linear copolymer is 0.910
~0.925g/ ^cm3 . The density of this linear ethylene copolymer is
If it is less than 0.910 g/cm ³ , the rigidity is insufficient. On the other hand, if it exceeds 0.925 g/cm ³ , it is unsuitable because the rigidity is high and the flexibility is insufficient. The α-olefin used in the production of the ethylene-based linear copolymer is an α-olefin having at most 12 carbon atoms, and typical examples include propylene, butene-1, hexene-1, and 4-methylpentene. -1 and octene-1. The copolymerization ratio of the α-olefin in this copolymer is usually 1.0 to 18% by weight. The short chain branch in this ethylene-based linear copolymer refers to a branch that is sufficiently short compared to the main chain, and has, for example, less than 15 carbon atoms.
On the other hand, a long chain branch means a branch having a length sufficiently comparable to the main chain, for example, having 15 or more carbon atoms. These random copolymers and ethylene-based linear copolymers can be obtained by copolymerizing ethylene and propylene or ethylene and the above-mentioned α-olefin using a so-called Ziegler catalyst or a Phillips catalyst. . Ziegler's catalyst is a transition metal compound (for example, a halogen-containing compound of titanium) or a carrier for the transition metal compound (for example, a magnesium-containing compound, a compound obtained by treating the magnesium-containing compound with an electron-donating organic compound). It is obtained from a so-called carrier-supported solid catalyst component obtained by supporting the catalyst component on a solid catalyst and an organoaluminum compound. Also,
Phillips catalyst is a carrier-supported catalyst obtained by supporting a chromium or molybdenum oxide or a compound of these oxides and zirconium on a carrier (for example, silica, silica-alumina), or a carrier-supported catalyst and an organic metal. It is obtained from a compound. The above catalysts are merely typical Ziegler catalysts and Phillips catalysts, and other known catalysts may also be used. The method for producing this copolymer is also a well-known method. (D) Composition ratio (content ratio) The composition ratio of the random copolymer and the rubber-like material in the composition obtained by the present invention is 30 to 80% by weight in total. If the composition ratio of the random copolymer and the rubbery material in the composition is less than 30% by weight in total,
The resulting composition has poor heat resistance. On the other hand, if it exceeds 80% by weight, low-temperature impact resistance will be low. In addition, the proportion of the random copolymer in the total of the random copolymer and the rubbery material is 99 to 50% by weight, preferably 90 to 60% by weight, especially 85 to 50% by weight.
70% by weight is preferred. If the proportion of the random copolymer in the total of the random copolymer and the rubber-like material exceeds 99% by weight, impact resistance and flexibility at low temperatures will be insufficient;
If it is less than that, there are problems such as stickiness and high cost. (E) Mixing method In producing the composition of the present invention, it can be obtained by uniformly mixing the random copolymer, rubber-like material, and ethylene-based linear copolymer. In this case, all the ingredients may be mixed at the same time, or some of the ingredients may be mixed in advance, and the remaining ingredients may be mixed into the resulting mixture. In addition, depending on the purpose of use of the resulting composition, antiaging agents, antioxidants, ultraviolet absorbers, plasticizers, fillers, Additives such as lubricants, flame retardants, antistatic agents, and colorants may be added to the extent that they do not substantially impair the above-mentioned properties of the copolymer. Mixing methods include dry blending using a mixer such as a Henschel mixer, which is commonly used in the olefin resin industry, and melt kneading using a mixer such as a Banbury mixer, kneader, roll mill, and screw extruder. There is a way to do it. At this time, a more uniform composition can be obtained by dry blending or melt kneading in advance and further melt kneading the resulting composition (mixture). Furthermore, among the ethylene-based linear copolymers and propylene-based copolymers that are components of the composition, or these and the above-mentioned additives,
A part of the components may be mixed to produce a masterbatch, and other composition components may be mixed with this masterbatch to produce the composition used to produce the shock absorber of the present invention. In these cases, the mixture is generally melt-kneaded and then formed into pellets, which are then subjected to the forming described later. (F) Molding methods, etc. To produce various molded products using the composition of the present invention, molding methods commonly used in the field of commonly used ethylene polymers and propylene polymers are applied. do it. Examples of the molding method include injection molding, blow molding, extrusion molding, and compression molding. In order to produce various molded products using these molding methods, it is necessary to carry out the process at a temperature higher than the melting point of the linear ethylene copolymer and propylene copolymer used. Of course, the process must be carried out at a temperature below that at which the polymer undergoes thermal degradation. From the above,
The molding temperature is 130-300℃. The resin composition in the present invention is highly flexible, and includes conventionally used polyurethane (RIM molding), TPE and propylene resin.
Rubber whose main components are ethylene and propylene,
It can replace soft resins typified by blends consisting of ethylene-vinyl acetate copolymer and/or low-density polyethylene having long chain branches, and is suitable for the above-mentioned uses. Physically, it has excellent heat resistance and low-temperature impact resistance, and is superior to the RIM polyurethane and T.
It has a significantly higher gloss than PE, does not cause flow marks, and has a good appearance. Furthermore, it is characterized by not being sticky like the blends described above and being inexpensive. [] Examples and Comparative Examples The present invention will be explained in more detail below using Examples. In addition, in the Examples and Comparative Examples, the tensile test was carried out under the conditions of a tensile speed of 200 mm/min based on JIS K-6301. Further, the Dupont impact strength was measured as follows immediately after immersing the flat plate (sample) used for measuring the molding shrinkage rate described later in a dry ice-methyl alcohol solution (-60°C). Steel cylinder (thickness 2 mm, diameter 46
A 2 kg load weight (tip radius: 1/2 inch) was placed on the sample from a height of 150 cm, and the presence or absence of cracks was observed. Furthermore, the surface hardness (Shoer D) was measured based on ASTM D-2240. In addition, gloss was measured based on JIS Z-8741. Furthermore, heat sagging was determined by cutting out a sample with a width of 1/2 inch, a length of 5 inches, and a thickness of 2.0 mm from the molded piece used to measure the molding shrinkage rate.
One end was fixed, and the amount of deformation of the 100 mm long tip was measured after 30 minutes at a temperature of 80°C. In addition, the molding shrinkage rate is calculated using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., product name: IS).
-80A), the cylinder temperature is 230℃, the injection pressure is 60-75Kg/cm ² for the primary pressure, and 50-55 for the secondary pressure.
Kg/cm ² , injection time 12 seconds, cooling time 20 seconds, and mold temperature 50℃, the thickness is 2mm and
A flat plate of 110 x 150 mm was injection molded. M at this time
The molding shrinkage rates in the direction and T direction were measured. Examples 1 to 10, Comparative Examples 1 to 9 Ethylene-propylene random copolymer with an ethylene content of 7.5% by weight as a propylene copolymer [MFI 7.7 g/10 min (hereinafter referred to as "polymer (A)")
], an ethylene-based linear copolymer consisting of essentially linear random copolymerization of ethylene and butene-1 [density 0.920 g/cm ³ , M.
I.7.0 g/10 minutes, hereinafter referred to as "Polymer (B)"], a copolymer of essentially linear random copolymerization of ethylene and octene-1 [density 0.916 g/cm ³ , M.
I.15 g/10 minutes, hereinafter referred to as "polymer (C)" and a copolymer of essentially linear random copolymerization of ethylene and hexene-1 [density 0.917 g/cm ³ ,
MI 10 g/10 minutes, hereinafter referred to as "polymer (D)"] and ethylene-propylene-diene ternary copolymer rubber as a rubbery material [diene ethylidene norbornene, ethylene content 70% by weight, MI 0.2 g/10 minutes,
Hereinafter referred to as "polymer (E)" and ethylene-propylene copolymer rubber [ethylene content 72% by weight, M.
I.0.8g/10 minutes, hereinafter referred to as "polymer (F)"]
Each of the ingredients was dry blended for 5 minutes using a Henschel mixer at the blending ratio shown in the table. Pellets were produced by kneading each of the obtained mixtures using an extruder (diameter: 65 mm) set at a temperature of 220°C. Test pieces were made from each of the obtained pellets using a 5-ounce injection molding machine. The MFI of each pellet and the physical properties of each test piece were measured. The results are shown in Table 2.

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[Table] From the results of the above Examples and Comparative Examples, the composition obtained by the present invention not only has good impact resistance even at a fairly low temperature of -60°C, but also has good surface hardness and gloss. It also has good heat resistance, flexibility, and tensile properties.Furthermore, because the molding shrinkage rate is small, there are few sink marks, and it is clear that the appearance is good. On the other hand, compositions that do not contain rubbery substances (Comparative Examples 1 to 3) lack impact resistance and flexibility at low temperatures; ) is unsuitable because it reduces heat resistance and causes stickiness.

Claims (1)

[Claims] 1 (A) The ethylene content is 3 to 9% by weight,
Stiffness is 10000Kg/ ^cm2 or less and melt flow index is 0.5 to 20g/10
(B) at least one rubber-like material selected from the group consisting of (1) ethylene-propylene copolymer rubber and (2) ethylene-propylene-diene terpolymer rubber; and (C) short chain branching of ethylene having a melt index of 0.5 to 40 g/10 min and a density of 0.910 to 0.925 g/cm ³ and an α-olefin having at most 12 carbon atoms. A linear copolymer having a linear copolymer, wherein the total of the random copolymer and the rubbery material in the composition is 30 to 80% by weight, and the random copolymer and the rubbery material account for 30 to 80% by weight. The blending ratio of the random copolymer in the total is 99~
A resin composition characterized in that the content is 50% by weight.