JPS626585B2 - - Google Patents

Description

[Detailed description of the invention]

[] Background of the Invention Thermoplastic elastomers have been attracting attention as rubber or rubber-like materials that do not require a vulcanization process in the fields of automobile parts, home appliance parts, footwear, electric wires, miscellaneous goods, etc. In particular, polyolefin-based thermoplastic elastomers are different from those obtained by polymerizing hard segments and soft segments, such as other polystyrene-based and polyester-based thermoplastic elastomers, and differ from those obtained by polymerizing hard segments and soft segments. It is made by melt-kneading polyethylene, poly(ethylene-vinyl acetate, etc.) and polyolefin rubber as a soft segment, and in some cases, the rubber portion is partially cross-linked during melt-kneading. 49−
As seen in No. 53938 and Japanese Patent Publication No. 53-34210, studies have focused on ethylene propylene rubber/polypropylene rubber, which has the characteristics of being relatively inexpensive and having good flexibility, heat deformation resistance, and weather resistance. It is now being actively put into practical use in automobile parts and other applications. However, in order to obtain good flexibility and heat deformation resistance, it is necessary to use an elastomer (hereinafter referred to as EP rubber) made of ethylene propylene binary copolymer or ethylene propylene non-conjugated diene terpolymer as the soft segment polyolefin rubber. (collectively referred to as etc.) is extremely poor. The present inventors have already made a proposal to solve these problems (Japanese Unexamined Patent Application Publication No. 1983-1999).
No. 125138). [] Summary of the Invention Summary The present invention aims to solve these drawbacks, and attempts to achieve this objective by using a specific propylene copolymer as a resin component to be blended into EP rubber. It is something to do. Therefore, the thermoplastic elastomer composition according to the present invention is characterized in that it consists of a composite of component A and component B described below. Component A: Elastomeric copolymer consisting of ethylene, α-monoolefin and optionally a non-conjugated diene. Component B A resinous copolymer consisting of propylene, a C _5-12 linear α-olefin, and optionally ethylene or butene-1. However, the weight ratio of A/B is 1/99 to 80/20. In the present invention, the term "composite of component A and component B" refers to a composite of component A and/or component B partially crosslinked during mechanical melt-kneading, as well as a mechanically melt-kneaded product of both components. shall be included. Also,
"Consisting of" is to be understood as a term indicating that in addition to the constituents mentioned therein, non-essential auxiliary ingredients may also be included. Effects By using a specific propylene copolymer as a hard segment in the above EP rubber/polypropylene thermoplastic elastomer,
Good flexibility could be obtained at lower rubber concentrations compared to thermoplastic elastomers using conventional propylene polymers (homopolymer, ethylene block copolymer, and ethylene random copolymer). This has made it possible to significantly improve the injection moldability and appearance of injection molded products, which were the objectives of the present invention. Furthermore, even at the same rubber concentration, the thermoplastic elastomer of the present invention is significantly superior in terms of flexibility in terms of appearance of injection molded products, compared to conventional thermoplastic elastomers using polypropylene. Furthermore, as an unexpected effect, the non-crosslinked system has improved heat deformation resistance, and both non-crosslinked and partially cross-linked systems have the same flexibility, excellent oil resistance, mechanical strength and elongation properties, and conventional polypropylene systems have completely Stress whitening (bending whitening) that was impossible to prevent
It was possible to obtain a thermoplastic elastomer free of The property of the composition of the present invention that stress whitening does not occur is due to the fact that the α-olefin copolymerized with propylene (and optionally ethylene or butene-1) in component B is linear. appears to be at least partially responsible for the This is because in the prior invention of the present inventors (JP-A-55-125138), which corresponds to the use of a branched olefin as the α-olefin, stress whitening comparable to that of polypropylene systems may be observed. [] Detailed Description of the Invention The thermoplastic elastomer composition according to the present invention comprises:
It consists of a composite of component A, which is a soft segment, and component B, which is a hard segment. 1 Component A Component A as a soft segment is an ethylene-α-monoolefin copolymer rubber or an ethylene-α-monoolefin-nonconjugated diene copolymer rubber. A mixture of both can also be used. In the case of ethylene-α-monoolefin binary copolymer rubber, the ethylene content is 20 to 90% by weight, preferably 40 to 85% by weight, and the α-monoolefin content is 80 to 10% by weight, preferably 60 to 15% by weight. %,
The one is good. In the case of ethylene-α-monoolefin-nonconjugated diene terpolymer rubber, the above binary composition ratio is maintained and the nonconjugated diene content is 0 to 15% of the total.
% by weight, preferably 1 to 10% by weight. When two or more types of each component are used, the content of these components shall be considered in terms of their total amount. These EP rubbers have Mooney viscosity (M _L
1+4 100°C) 20 to 300 is suitable. As the α-monoolefin in these EP rubbers, one or more α-monoolefins having 3 to 12 carbon atoms are used. Among these, propylene is the most common. Non-conjugated dienes optionally used include 1,4-pentadiene, 1,
One or more types of linear dienes such as 4-hexadiene and 1,5-hexadiene, and cyclic polyenes such as dicyclopentadiene, methylene norbornene, ethylidene norbornene, cyclooctadiene, and methyltetrahydroindene are used. As such EP rubber, those manufactured by a known general method can be used as is. 2 Component B (1) Definition The propylene copolymer as a hard segment consists of propylene (monomer (1)) and C ₅ ~
It is a binary or ternary copolymer consisting of a C ₁₂ linear α-olefin (monomer (2)) and optionally ethylene or butene-1 (monomer (3)). The linear α-olefin of monomer (2) is selected from 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene and 1-dodecene. Among these, pentene-1, hexene-1,
Heptene-1 and octene-1 are preferred. In order to achieve an effect in accordance with the purpose of the present invention,
Component B must contain monomer (1) and monomer (2) as its constituent elements, but if it is necessary to emphasize the flexibility of the composition, monomer (3) may also be used. I can do it. Therefore, the preferred composition range of component B is:
The following areas are shown on the XY coordinate plane (where the X axis represents the monomer (2) content (wt%) and the Y axis represents the monomer (3) content (wt%)). 0.5 〓 Instead, it is expressed by a newly defined region using equation (2'), 1〓Y〓6 (2') and Y〓9-1/3X (3). If the copolymer composition deviates from this region, the flexibility of the composition will be lost if the position deviates toward the origin on the XY plane, and the heat resistance will be lost if the copolymer composition deviates in a direction away from the origin. (2) Production The component B copolymer is produced using a so-called Ziegler-type composite catalyst consisting of at least a titanium component and an organoaluminum compound. Typical titanium components of the catalyst include various α, β, γ, and δ types of titanium trichloride, and titanium trichloride and titanium tetrachloride supported on various carriers mainly composed of magnesium chloride. Among them, titanium trichloride is obtained by extracting and removing aluminum chloride using a complexing agent from a eutectic composite of titanium trichloride and aluminum chloride, which is obtained by reducing titanium tetrachloride using an organic aluminum compound or metal aluminum. Compositions or compositions in which various types of titanium trichloride or titanium tetrachloride are supported on a carrier containing magnesium chloride are advantageous because of their high activity. In particular, the use of complexed-extracted titanium trichloride compositions
This is most advantageous because the resulting copolymer has a good particle morphology and the efficiency of introducing monomer (2) and monomer (3) into the copolymer is high. In addition to these, all compounds known to have an olefin polymerization ability can be used, such as tetra- to divalent titanium halides, alkyl halides, alkoxides, and alkoxy halides. _The organoaluminum compound used in combination with _the above titanium component _{has the} general _formula AlR _n Typical examples include alkoxy groups of the order of magnitude (m is a number of 1〓m〓3). Preferred examples include triethylaluminum, tri-i
-butylaluminum, tri-n-octylaluminum, diethylaluminium hydride, diethylaluminium chloride, diethylaluminium iodide, ethylaluminum sesquichloride, ethylaluminum dichloride, and the like. It is also possible to improve activity, stereoregularity, particle properties, etc. by adding various electron-donating compounds to the titanium component and organoaluminum compound. Such electron-donating compounds are exemplified in detail in, for example, JP-A-54-39483. Copolymerization is produced through one or more steps. In this case, the copolymerization must be carried out in at least one step in which monomer (1), monomer (2), and optionally monomer (3) are simultaneously present in the polymerization system. At this stage, a di- or ternary random copolymer of monomers (1) and (2) and optionally monomer (3) is formed. This step can be preceded and/or followed by a homopolymerization step of any monomer or a random copolymerization step of a combination of different monomers. Examples of preferred combinations of polymerization steps are as follows. However, M ₁ and M ₂ represent monomers 1 and 2, respectively, / represents the coexistence of monomers, and 1 represents the connection of each polymerization step. Example of one-stage polymerization method M ₁ /M ₂ M ₁ /M ₂ / _M3 Example of multi-stage polymerization method M ₁ −M ₁ /M ₂ M ₁ −M ₁ /M ₂ /M ₃ M ₁ −M ₁ / M ₂ −M ₂ ／M ₃ M ₁ ／M ₁ ／M ₂ ／M ₃ −M ₂ ／M ₃ M ₃ −M ₁ ／M ₂ M ₃ −M ₁ ／M ₂ ／M ₃ Among these, multistage For legal copolymers, the proportion of the polymer produced in each step in the total copolymer and the composition of the polymer produced in each step can be freely varied within the constraints of the content of each monomer unit mentioned above. However, in that case, the criteria for determining the composition are the requirements for the balance between heat deformation resistance and flexibility of the final copolymer, as well as maintaining stable and economical operating conditions for the given copolymerization equipment. Should be. As an example, regarding the copolymer produced by the M ₁ -M ₁ /M ₂ method, the proportion of the M ₁ homopolymer portion produced in the first step in the entire copolymer is 0.5 to 50% by weight; The amount is preferably 2 to 30% by weight, more preferably 5 to 20% by weight, and the remainder is the M ₁ /M ₂ random copolymer portion. 3. Composite of component A and component B (1) Composition The ratio of component A to component B in the composition of the present invention is 1/99 to 80/20 in weight ratio of A/B. The preferred range of this ratio is determined by the desired physical properties of the product composition. That is, compared to those using conventional propylene polymers (homopolymer, ethylene block copolymer, ethylene random copolymer, etc.), A/B = 1/99 to 60/40.
In particular, in the range of A/B = 20/80 to 60/40, partially crosslinked systems have excellent moldability, appearance of molded products, oil resistance, and stress whitening, and non-crosslinked systems have even better heat deformation resistance. There is a characteristic that Furthermore, when A/B is in the range of 60/40 to 80/20, thermoplastic elastomers, both non-crosslinked and partially crosslinked, can be obtained which have particularly excellent flexibility and mechanical strength. (2) Composite The present invention can be obtained by combining component A and component B. The composite means in this case is basically mechanical melt-kneading, as in the case of producing a normal resin composition, but a crosslinking agent is present during the melt-kneading, and either one of the components A and B is mixed. Partial crosslinking can also occur between both or both. Mechanical melt kneading methods include single screw extruder,
General melt kneading machines such as a twin screw extruder, Banbury mixer, and various kneaders can be used. As the crosslinking agent to be added during melt-kneading to obtain a partially crosslinked product, aromatic or aliphatic peroxides or azo compounds are suitable. These may be used alone or in combination. Further, sulfur may be used in combination. Specific crosslinking agents include 2,5-dimethyl-2,5(benzoylperoxy)hexane, t-butylperoxyperbenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-di(t −
butylperoxy)hexane, t-butylcumyl peroxide, diisopropylbenzohydroperoxide, 1,3-bis-t
-butylperoxyisopropylbenzene, etc. The gel fraction of partially crosslinked materials is generally in the range of 20 to 95% by weight as insoluble matter when immersed in cyclohexane at 23°C. During crosslinking during mechanical melt-kneading, in order to make the crosslinking uniform and control the crosslinking reaction,
A crosslinking reaction retarder can also be used in combination, if necessary. The crosslinking reaction retarders used include hydroquinone, 2,6-di(t-butyl)-p-cresol, t-butylcatechol, 4,4'-butylidenebis(3-methyl-
6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-thiobis(6-t-butyl-3-methylphenol), mercaptobenzothiazole, Dibenzothiazole disulfide, 2,2,4-trimethyl-1,2
-dihydroquinone polymer, phenyl-β-
There are organic peroxide crosslinking scorch inhibitors such as naphthylamine, N.N'-di-β-naphthyl-p-phenylenediamine, and N-nitrosodiphenylamine. The composition of the present invention blends commonly used fillers such as carbon and white fillers, paraffin, naphthenic process oil, plasticizers such as dioctyl phthalate, and pigments, as is done for ordinary resin compositions. There will be a day when you can use it. Further, additives such as a heat stabilizer, an antioxidant, and an ultraviolet absorber can be added as necessary. Other third component polymers to the extent that the properties as a thermoplastic elastomer are not impaired, such as polar group-introduced polyolefins (e.g., ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, maleic anhydride grafted polypropylene, etc.), Polyamide resins, polyester resins, thermoplastic styrene-butadiene copolymers, etc. can also be added. The composition of the present invention can be molded using a commonly used thermoplastic resin molding machine, and thermoplastic resin molding methods such as injection molding, extrusion molding, blow molding, and calendar molding can be applied. . Particularly, those having A/B=1/99 to 60/40 are suitable for injection molding. The products obtained by each of the above molding methods have an excellent quality balance in flexibility, heat deformation resistance, molding processability, molded product appearance, oil resistance, mechanical strength, and physical properties, and are resistant to stress whitening (bending whitening). It is not a thermoplastic elastomer molded product. 4 Experimental Examples The following examples and comparative examples specifically illustrate the present invention. () Test method During the following experiment, the test method used to indicate the physical properties of each component and evaluate the resulting composition is as follows. (1) Melt index (230℃) ASTM-D-1238 [g/10min] (2) Mooney viscosity (M _L1+4 100℃) JIS-K-6300 [-] (3) Gel fraction cyclohexane immersion Insoluble content at 23°C/48 hours [wt%] (4) Olzen bending stiffness (10 degree angle) ASTM-D-747 (sample = 2 mm thick press sheet) (5) Deformation rate under heat and pressure In heated silicone oil The sample (1 cm x 1 cm x 2 mm
Attach a thick press sheet) and heat to 130℃.
After being left at ℃ for 1 hour under a load of 3 kg, the load was removed and the thickness deformation rate was obtained after 10 minutes.
[%] (6) Tensile strength JIS-K-6301 test piece No. 3 [Kg/cm ² ] (Sample = 2 mm thick injection molded sheet) (7) Tensile elongation JIS-K-6301 test piece No. 3 Shape [%] (Sample = injection molded sheet with a thickness of 2 mm) (8) Stress whitening When a press sheet with a thickness of 10 cm x 2 cm x 2 mm is bent in half, the state of whitening at the folded part is evaluated in the following three stages. evaluate. Evaluation criteria 〇 = No whitening at all △ = Only slight whitening × = Completely whitened (9) Immersion test (mass change rate) Pressed sheet of 5cm x 2cm x 2mm thickness.
Obtained from the mass change rate when immersed in ASTM-2 oil at 50℃ for 100 hours. [%] (10) Fluidity In a high-performance flow tester, a sample was placed in a 10 mm diameter cylinder, heated to 200°C, a load of 30 kg was applied, and the sample flowed out from a 1 mm diameter x 2 mm length orifice installed at the bottom of the cylinder. obtained by the amount of resin per second. [×10 ^-3 cc/sec] (11) Appearance of injection molded product Injection molding machine and molding conditions Model 16oz in-line screw type Conditions Injection pressure 500-1000Kg/cm ³ Injection temperature 200-230℃ Mold temperature 40℃ The appearance was visually evaluated from three points: flow marks, weld marks, and gloss. Evaluation criteria 〇=Good △=Slightly poor ×=Poor () Supplied samples The contents of each sample are as follows. (1) EP-1 has Mooney viscosity (M _L1+4 , 100
EP DM (ethylene-propylene-nonconjugated diene elastomer) has a propylene content of 25% by weight and a content of 15% in terms of iodine value using ethylidene norbornene as the third component (diene compound). ). (2) EP-2 has Mooney viscosity (M _L1+4 , 100
℃) is 83, the propylene content is 43% by weight, ethylidene norbornene is used as the third component (diene compound), and the content is 26 in terms of iodine value. (3) PP-1 is a propylene-hexene 1 copolymer produced as follows, with a hexene-1 content of 13.8% by weight and a melt index of 5.7 g/10 minutes. After sufficiently replacing the interior of the stirred polymerization reactor with an internal volume of 150 liters with propylene, the n-
45 liters of heptane, 3.9 g of titanium trichloride (TAU catalyst manufactured by Marubeni/Solvay Chemical),
19.5 g of diethyl aluminum chloride was added. Temperature 50℃, propylene pressure 2.0
Kg/cm ² G was maintained for 20 minutes to carry out homopolymerization of propylene. Then increase the temperature to 60℃
Propylene and hexene-1 were fed at a rate of 3.5 Kg/hr and 9.0 L/hr, respectively, over 2.75 hours. Then, the supply of hexene-1 was stopped and only propylene was supplied at a rate of 3.5 kg/hour over 0.75 hours. Furthermore, the supply of propylene was also stopped, and copolymerization using only unreacted monomers was carried out.
Lasted for an hour. During this time, hydrogen was continuously supplied so that the hydrogen concentration in the gas phase of the reactor was 5.5% by volume. After copolymerization, residual gas was removed, the copolymer slurry was transferred to another tank, and 45 liters of n-heptane and n-heptane were added to clean the inside of the polymerization vessel.
1.2 liters of butanol and 9 g of potassium hydroxide were added, and the mixture was stirred at 65° C. for 2 hours (decontamination and neutralization). The copolymer is removed as a cake containing the solvent by centrifugation,
This was treated with 65 liters of pure water containing 8 g of nonionic emulsifier at 100 DEG C. and the solvent was steam stripped. After that, the copolymer was removed by centrifugation,
A product copolymer was obtained by vacuum drying. The resulting copolymer product weighed 10.6 kg. (4) PP-2 is a propylene-hexene-1-ethylene terpolymer produced as follows, and the hexene-1 and ethylene contents are 9.4% by weight and 1% by weight, respectively.
17.8% by weight, and the melt index is
It is 4.6g/10 minutes. Using the reactor used to produce PP-1 above, after replacing the interior with propylene, 45 liters of n-heptane and titanium trichloride (the same as used in Reference Example 1) were added.
7.6g, diethylaluminum chloride 33
I put g. Temperature: 50℃, propylene pressure:
Homopolymerization of propylene was carried out by maintaining the condition at 2.0 Kg/cm ² ·G for 20 minutes. The temperature was then raised to 60°C and propylene and hexene
Random copolymerization of propylene and hexene-1 was carried out while feeding 1 at a rate of 3.0 kg/hour and 6.0 liters/hour, respectively, over a period of 4 hours. Here, propylene was purged until the pressure in the gas phase reached 0.4 Kg/cm ² ·G, and then ethylene was supplied at a rate of 1.8 Kg/hour for 2.5 hours, while unreacted hexene with ethylene was supplied. Random copolymerization with 1 was carried out. During this time, the hydrogen concentration in the gas phase of the reactor was reduced to 5.5% by volume.
Hydrogen was continuously supplied so that The polymer slurry after completing the series of copolymerization reactions was post-treated in the same manner as in the production of PP-1 described above to obtain 11.8 kg of product copolymer powder. (5) PP-3 is an isotactic polypropylene homopolymer with a melt index of 5 g/10 minutes. (6) PP-4 is a propylene-ethylene block copolymer with an ethylene content of 8.0
% by weight, melt index 5.6 g/10 min. (7) PP-5 is a propylene-ethylene random copolymer with an ethylene content of 5.5
% by weight, melt index 5 g/10 min. (8) The crosslinking agent (organic peroxide) is 1,3 bis-(t-butylperoxyisopropyl)
This is a 40% diluted product in benzene. (9) The crosslinking reaction retarder is dibenzothiazole disulfide. () Manufacture of Composition Using a 1.0 liter pressure kneader for rubber, the above sample was melt-kneaded at a set temperature of 170° C. for 10 minutes to prepare a sample. For partially crosslinked products, after melt-kneading component A and component B for about 3 minutes, add a crosslinking agent and a crosslinking reaction retarder, and after addition,
A sample was obtained by melt-kneading for 7 minutes and crosslinking. However, for Examples 6 and 7,
Since component B is blended in the same amount or more as component A, in order to prevent component B from deteriorating due to the addition of a crosslinking agent (organic peroxide), first add 60 parts by weight of component A and 40 parts by weight of component B as described above. After preparing the crosslinked composition, a required amount of component B was further added to produce a predetermined composition. () Composition and physical properties (1) The following thermoplastic elastomer was manufactured using conventional polypropylene. Comparative Example 1 (Non-crosslinked system) The Olzen bending stiffness of a non-crosslinked thermoplastic elastomer obtained using 60 parts by weight of EP-1 as component A and 40 parts by weight of PP-3 as component B was 1650 kg/cm ² . Comparative Example 2 (Partially crosslinked system) Partially crosslinked thermoplastic elastomer obtained with 65 parts by weight of EP-2 as component A and 35 parts by weight of PP-4 as component B. In addition, 0.5 parts by weight of a crosslinking agent and 0.05 parts by weight of a crosslinking reaction retarder. The Olzen bending stiffness of the material was 450 Kg/cm ² .
The gel fraction of this product was 82% by weight. In contrast, we searched for compositions that would provide the same flexibility as the thermoplastic elastomers of the present invention, and found the following compositions. Example 1 (Non-crosslinked system) Component A was 20 parts by weight of EP-1, and component B was 80 parts by weight of PP-1. Example 2 (Partially crosslinked system) 40 parts by weight of EP-2 as component A and 60 parts by weight of PP-1 as component B. In addition, 0.5 part by weight of crosslinking agent and 0.05 part by weight of crosslinking reaction retarder were used to give a gel fraction of 81% by weight. . From the above, it has been found that the thermoplastic elastomer obtained according to the present invention has the same flexibility and requires a significantly smaller proportion of rubber than the conventional thermoplastic elastomer using polypropylene. Table 1 shows the injection moldability and appearance of the molded product with this composition.
As shown, there has been a significant improvement.

[Table] (2) The following thermoplastic elastomer was manufactured using conventional polypropylene. Comparative Example 3 (Partially crosslinked system) 60 parts by weight of EP-2 as component A 40 parts by weight of PP-4 as component B In addition, 0.5 part by weight of crosslinking agent and 0.05 part by weight of crosslinking reaction retarder, the gel fraction was 80% by weight. On the other hand, the thermoplastic elastomers of the present invention manufactured using the same EP rubber and the same formulation are as follows. Example 3 (Partially crosslinked system) 60 parts by weight of EP-2 as component A 40 parts by weight of PP-1 as component B. In addition, 0.5 part by weight of crosslinking agent and 0.05 part by weight of crosslinking reaction retarder were used to give a gel fraction of 81% by weight. Table 2 shows the appearance and flexibility of injection molded products of thermoplastic elastomers of Comparative Example 3 and Example 3.
This shows that even with the same rubber content, the injection molded product of the present invention has a significantly superior appearance and flexibility.

[Table] (3) The following thermoplastic elastomer was manufactured using conventional polypropylene. Comparative Example 4 (Non-crosslinked system) The Olzen bending of a non-crosslinked thermoplastic elastomer obtained using 50 parts by weight of EP-1 as component A and 50 parts by weight of PP-4 as component B was 2300 kg/cm ² . Comparative Example 5 (Non-crosslinked system) A non-crosslinked thermoplastic elastomer obtained using 65 parts by weight of EP-1 as component A and 35 parts by weight of PP-4 as component B had an Olzen flexural rigidity of 820 kg/cm ² . Comparative Example 6 (Partially crosslinked system) Partially crosslinked thermoplastic elastomer obtained with 70 parts by weight of EP-1 as component A and 30 parts by weight of PP-3 as component B. In addition, 0.5 parts by weight of a crosslinking agent and 0.05 parts by weight of a crosslinking reaction retarder. The Olzen bending stiffness was 470Kg/ ^cm2 .
The gel fraction of this product was 79% by weight. On the other hand, the thermoplastic elastomer of the present invention
As shown in Table 3, it can be seen that the following compositions, each having the same Olzen bending rigidity as the previous ones, are significantly superior in oil resistance and stress whitening. Example 4 (non-crosslinked system) EP-1 as component A 40 parts by weight PP-1 as component B 60 Example 5 (partially crosslinked system) EP-2 as component A 50 parts by weight PP-2 as component B 50 In addition, 0.5 parts by weight of cross-linking agent and 0.05 parts by weight of cross-linking reaction retardant give a gel fraction of 81 parts by weight.

[Table] (4) Table showing the heat deformation resistance of Example 1 and Comparative Example 1.
4. This shows that the product of the present invention has better heat deformation resistance than the conventional non-crosslinked thermoplastic elastomer using polypropylene at the same level of flexibility.

[Table] (5) The following thermoplastic elastomer was manufactured using conventional polypropylene. Comparative Example 7 (Non-crosslinked system) The Olzen bending stiffness of a non-crosslinked thermoplastic elastomer obtained using 70 parts by weight of EP-1 as component A and 30 parts by weight of PP-5 as component B was 380 kg/cm ² . On the other hand, the thermoplastic elastomer of the present invention has the following composition and has the same Olzen bending rigidity as this, and is significantly superior in tensile strength and elongation as shown in Table 5. Example 6 (Non-crosslinked type) A non-crosslinked thermoplastic elastomer was obtained using 60 parts by weight of EP-1 as component A and 40 parts by weight of PP-1 as component B.

[Table] (6) A partially crosslinked thermoplastic elastomer according to the present invention having the following components was manufactured. Example 7 (Partially crosslinked system) 80 parts by weight of EP-2 as component A 20 parts by weight of PP-1 as component B In addition, 0.5 part by weight of crosslinking agent and 0.05 part by weight of crosslinking reaction retarder, gel fraction was 73 parts by weight. This product had an Olzen bending stiffness of 40 kg/cm ² and excellent flexibility. A product having similar flexibility was manufactured using conventional polypropylene and had the following formulation. Comparative Example 8 (Partially crosslinked system) 90 parts by weight of EP-2 as component A and 10 parts by weight of PP-3 as component B. In addition, 0.5 part by weight of crosslinking agent and 0.05 part by weight of crosslinking reaction retarder, gel fraction 70 parts by weight. This product suffered significant deformation, delamination, etc. during injection molding, and could not be used as a thermoplastic elastomer.

Claims (1)

[Scope of Claims] 1. A thermoplastic elastomer composition comprising a composite of component A and component B below. Component A: Elastomeric copolymer consisting of ethylene, α-monoolefin and optionally a non-conjugated diene. Component B A resinous copolymer consisting of propylene, a C ₅ -C ₁₂ linear α-olefin, and optionally ethylene or butene-1. However, the weight ratio of A/B is 1/99 to 80/20.