JP2746466B2 - Resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition suitable for thermoforming such as hot flow stamping. More specifically, by thermoforming such as hot flow stamping molding, not only can a molded article having a surface appearance similar to that obtained by injection molding be produced, but also rigidity is excellent,
The present invention also relates to a resin composition having good impact resistance and light weight.

[Prior art] Conventionally, propylene polymer (polypropylene resin)
Is not only excellent in various mechanical properties, but also has good molding processability and is relatively chemically stable, so it is widely molded into various automotive parts by molding methods such as hot flow stamping molding and vacuum molding. Have been. But,
When manufacturing by the hot flow stamping molding method, when filling the mold with the molten material, the temperature difference between the mold and the resin causes uneven cooling, which lowers the product value and is used only for functional materials. It is not at present. For this reason, a product having an excellent surface appearance comparable to a molded product obtained by the injection molding method has not been obtained so far.

Furthermore, the polypropylene-based resin has good moldability as described above, and various mechanical properties are excellent.
Of the mechanical properties, rigidity (flexural modulus) is not always satisfactory when used for automobile parts such as bumpers. Therefore, it has been proposed to improve the flexural modulus by further blending a filler with the ethylene-propylene block copolymer and the ethylene-propylene copolymer rubber (see, for example, JP-A-58-11).
No. 1846, No. 57-73034, No. 57-159841, No. 63-4342
issue).

In addition, Applicants have proposed that (A) propylene homopolymer and / or propylene-ethylene random copolymer, (B) ethylene-
A propylene-based polymer composition comprising a propylene random copolymer, (C) an ethylene-propylene copolymer and (D) talc has been previously proposed (Japanese Patent Laid-Open No. 1-20).
3898).

[Problems to be Solved by the Invention] However, regarding the composition for bumpers,
All have good impact strength, especially at low temperatures (for example, 0 to-
(40 ° C). In addition, the invention proposed by the applicant of the present application has advantages such as good adhesion of the urethane paint and excellent gasohol resistance, but the rigidity is not always satisfactory. (Ie, low flexural modulus).

In addition, in improving the synthetic resin molten material by hot-flow stamping molding, when the polypropylene resin is a crystalline material, cooling unevenness occurs when the polypropylene resin melted on the mold is solidified. Although it occurs, the following three methods can be considered as a method of suppressing this.

(1) A method of slowing down the crystallization speed.

(2) A method of lowering the crystallinity.

(3) A method of delaying the induction time until crystallization starts.

Among the above methods, the method of slowing down the crystallization rate means slowing down the cooling of the polypropylene resin which is the material to be melted, and is not economical because the molding cycle becomes long. Also, lowering the crystallinity is not advisable because it lowers the mechanical strength of the material and narrows the value of the function itself and its application.

From the above, the present invention is one of the above three methods,
It is an object of the present invention to obtain a resin composition which is particularly lightweight, has excellent rigidity and good impact resistance by a method of delaying the induction time until the crystallization starts (extending the induction time). .

[Means for Solving the Problems] According to the present invention, these problems are as follows: (A) Even if the xylene-soluble matter is large at a temperature of 30 ° C.,
(B) a xylene-insoluble matter at a temperature of 30 ° C.
5.0% by weight, and the copolymerization ratio of propylene is 30 to 7
(C) ethylene-propylene random copolymer having a copolymerization ratio of ethylene of 1.0 to 10% by weight, (D) Mooney viscosity [ML _{1 + 4} , (100 (C) is from 20 to 100, and an amorphous ethylene-propylene copolymer having a propylene content of less than 20 to 30% by weight, and (E) a filler. The composition ratio of the filler is 9.0
~ 23 wt%, the composition ratio of the ethylene-propylene random copolymer in the total amount of the propylene homopolymer and the ethylene-propylene random copolymer is 5.0
The melt index of the total of these polymers (measured at 14 in Table 1 according to JIS K7210, hereinafter referred to as MFR) is 2.0 to 200 g / 10 min. Propylene homopolymer and ethylene occupy in the total amount of “copolymer, ethylene-propylene random copolymer, propylene-ethylene random copolymer and amorphous ethylene-propylene copolymer” (hereinafter referred to as “all polymers”). The composition ratio of the total propylene random copolymer is 40 to 80% by weight, and the composition ratio of the propylene-ethylene random copolymer in the total amount of all the polymers is less than 25% by weight. The composition ratio of the propylene homopolymer and the ethylene-propylene random copolymer with respect to 1 part by weight of the random copolymer was 2.5 parts by weight as the total amount thereof. Over, but 9.0 parts by weight at most, yet amorphous ethylene in the whole polymer - composition percentage of the propylene copolymer of at least 5.0
% By weight, but the composition ratio of the amorphous ethylene-propylene copolymer and the ethylene-propylene random copolymer can be solved by a resin composition whose total amount is at most 40% by weight.

 Hereinafter, the present invention will be described specifically.

(A) Propylene homopolymer The propylene homopolymer used in the present invention is 30 ° C.
Contains at most 5.0% by weight (preferably 3.0% by weight or less) of a component soluble in xylene at the above temperature. The MFR of the polymer is generally 2.0 to 200 g / 10 minutes, preferably 5.0 to 200 g / 10 minutes, and more preferably 5.
Those having 0 to 180 g / 10 minutes are suitable. If a propylene homopolymer having an MFR of less than 2.0 to 10 minutes is used, the kneading property is not good and the composition is not good in moldability. On the other hand, 200g / 10
If the amount exceeds minutes, the impact resistance of the composition is not good.

(B) Ethylene-propylene random copolymer The propylene copolymerization ratio of the ethylene-propylene random copolymer used in the present invention is 30 to 75.
%, Preferably 30 to 70% by weight, especially 30 to 60% by weight.
% By weight is preferred. When an ethylene-propylene random copolymer having a propylene copolymerization ratio of less than 30% by weight is used, the impact resistance of the composition is poor. On the other hand, an ethylene-propylene random copolymer having a copolymerization ratio of propylene exceeding 75% by weight is difficult to produce, and even if obtained, there is a problem in the rigidity of the composition.

The ethylene-propylene random copolymer contains at most 5.0% by weight of a component insoluble in xylene at a temperature of 30 ° C.
(Preferably 4.5% by weight or less).

The above propylene homopolymer and ethylene-propylene random copolymer are produced by homopolymerization and copolymerization, respectively, and may be mixed at the composition ratio described below when producing the composition of the present invention. The polymer may be produced by so-called block copolymerization in which ethylene and propylene are copolymerized in the same polymerization vessel or another polymerization vessel in the presence of the polymer and the catalyst system used for producing the polymer.

In any of the above cases, the MFR of the sum of the propylene homopolymer and the ethylene-propylene random copolymer
Is 2.0-200g / 10min, preferably 5.0-200g / 10min,
Especially, 5.0 to 180 g / 10 minutes is suitable. If the MFR of the total amount of the propylene homopolymer and the ethylene-propylene random copolymer is less than 2.0 g / 10 minutes, the kneading properties and the moldability of the composition will be poor. On the other hand, if it exceeds 200 g / 10 minutes, the mechanical properties of the composition, especially the impact resistance, are poor.

(C) Propylene-ethylene random copolymer Further, the propylene-ethylene random copolymer of the present invention has an ethylene copolymerization ratio of 1.0 to 10% by weight,
-8.0% by weight is desirable, and especially 2.0-7.0% by weight is suitable. If a propylene-ethylene random copolymer having an ethylene copolymerization ratio of less than 1.0% by weight is used, a composition having good impact resistance cannot be obtained. On the other hand, if it exceeds 10% by weight, the heat resistance is undesirably reduced.

The propylene-ethylene random copolymer MF
R is 2.0 to 100 g / 10 minutes, preferably 3.0 to 80 g / 10 minutes, and particularly preferably 5.0 to 70 g / 10 minutes for the same reason as in the case of the above-mentioned propylene homopolymer.

(D) Amorphous ethylene-propylene copolymer Further, the amorphous ethylene-propylene used in the present invention
Mooney viscosity of propylene copolymer [ML _{1 + 4} , (100
℃)] is 20 to 100, preferably 20 to 80, and more preferably 3 to
0-75 is preferred. When an amorphous ethylene-propylene copolymer having a Mooney viscosity of less than 20 is used, the moldability is improved, but delamination may occur when the resin passes through the gate, which may cause trouble. On the other hand, when using more than 100, not only it becomes difficult to uniformly disperse with other composition organisms at the time of kneading, but even if a uniform composition is obtained, a flow mark is formed on the surface of the molded product. , Weld lines and the like become conspicuous, and a molded article having good appearance cannot be obtained. Further, the propylene content of the copolymer is generally less than 20 to 30% by weight, especially 25 to 30% by weight.
Less than 10% by weight is desirable. This amorphous ethylene-propylene copolymer has rubber-like properties, is industrially produced, is used in various fields, and its production method is widely known.

The amorphous ethylene-propylene copolymer is substantially amorphous and has a crystallinity measured by X-ray of less than 3%.

(E) Filler The filler used in the present invention is generally widely used in the synthetic resin and rubber fields.
Among these fillers, the inorganic filler is preferably an inorganic compound that does not react with oxygen and water and does not decompose during kneading and molding. Examples of the inorganic filler include oxides of metals such as aluminum, copper, iron, lead, nickel, magnesium, calcium, barium, zinc, zirconium, molybdenum, silicon, antimony, and titanium, and hydrates (hydroxides) thereof. , Sulfates, carbonates, silicates, and the like, double salts thereof, and mixtures thereof. Representative examples are described in JP-A-59-8535. Among these inorganic fillers, the powdery ones having a particle size of 30 μm or less (preferably 10 μm or less) are preferable. In the case of a fibrous material, the diameter is preferably 1 to 500 μm (preferably 1 to 300 μm) and the length is preferably 0.1 to 6 mm (preferably 0.1 to 5 mm). Further, it is preferable that the flat plate has a thickness of 30 μm or less (preferably 10 μm or less). Among these inorganic fillers, particularly, those having a flat (flake) shape and a powder shape are preferable.
Examples include talc, mica, silica, glass fiber, and graphite.

Examples of the organic filler include wood flour, organic fiber, straw, rice husk, and peanut kara.

The wood flour is usually of a 12 mesh pass, and particularly preferably has a particle size of 45 mesh pass or less. Note that the type of the wood flour is not particularly limited.

The organic fibers are animal fibers such as wool, plant fibers such as cotton, jute and pulp, and synthetic fibers such as generally used vinylon fiber, polyester fiber, nylon fiber and acrylic fiber. Since the length and average diameter of these organic fibers vary depending on the use of the composition finally obtained, mixing conditions, and the like, they cannot be unconditionally specified, but generally, the average diameter range is 3 to 500 μm, Those having a length of 0.1 to 6 mm are suitable.

In addition, straw is cut and used so as to have the same average diameter and length as the organic fibers from the viewpoint of mixing properties.

In addition, rice husks and peanuts are used after being crushed like the wood powder.

(F) Composition ratio In the resin composition of the present invention, the composition ratio of the ethylene-propylene random copolymer in the total amount of the propylene homopolymer and the ethylene-propylene random copolymer is 5.0 to 30% by weight, 5.0 to 25% by weight is preferred, and 7.0 to 25% by weight is preferred. When the composition ratio of the ethylene-propylene random copolymer in the total amount of the propylene homopolymer and the ethylene-propylene random copolymer is less than 5.0% by weight, the resulting composition has poor impact resistance, If the amount exceeds the weight percentage, the rigidity of the composition decreases.

The propylene homopolymer, ethylene-propylene random copolymer, propylene-ethylene random copolymer, and amorphous ethylene-propylene copolymer (ie, all polymers) occupy the propylene homopolymer and ethylene-propylene random copolymer. The composition ratio of the copolymer is
It is 40 to 80% by weight, preferably 42 to 80% by weight, particularly preferably 45 to 75% by weight. If the composition ratio of the propylene homopolymer and the ethylene-propylene random copolymer in the total polymer is less than 40% by weight, the impact resistance of the obtained composition is not good. Since the rigidity is reduced, the mechanical strength of the molded product is reduced.

Further, the composition ratio of the propylene-ethylene random copolymer in the total polymer is less than 30% by weight,
% By weight and less than 30% by weight, preferably 7.0% by weight and less than 30% by weight. Propylene in total polymer
If the copolymerization ratio of the ethylene random copolymer is less than 5.0% by weight, the obtained composition cannot be delayed to satisfy the induction time until crystallization starts. On the other hand, 30
When the content is not less than% by weight, the rigidity of the obtained composition is low.

Further, the composition ratio of the propylene homopolymer and the ethylene-propylene random copolymer to 1 part by weight of the propylene-ethylene random copolymer exceeds 2.5 parts by weight in total, but is at most 9.0 parts by weight,
2.5 to 8.5 parts by weight are desirable, and 2.8 to 8.0 parts by weight are particularly preferred. Propylene-ethylene random copolymer 1
Propylene homopolymer and ethylene-
Composition ratio of propylene random copolymer as total amount
When the amount is less than 2.5 parts by weight, the induction time is short, the appearance is deteriorated, and the rigidity is reduced. On the other hand, if it exceeds 9.0 parts by weight, the impact resistance is significantly reduced, and the creep strength at high temperatures is reduced.

Further, the composition ratio of the amorphous ethylene-propylene copolymer in the whole polymer is at least 5.0% by weight. However, if it is added in an amount exceeding 25% by weight, the moldability of the obtained composition is reduced. From these facts, the composition ratio of the amorphous ethylene-propylene copolymer in the total polymer is preferably from 7.0 to 25% by weight, and particularly preferably from 7.0 to 20% by weight.

The total composition ratio of the amorphous ethylene-propylene copolymer and the ethylene-propylene random copolymer in the total polymer is at most 40% by weight from the viewpoint of heat resistance and rigidity. However, when the total composition ratio of these polymers in the total polymer exceeds 40% by weight, the induction time is short, cooling unevenness easily occurs, and the appearance is deteriorated.
From these facts, amorphous ethylene in the total polymer
The total composition ratio of the propylene copolymer and the ethylene-propylene random copolymer is preferably from 7.0 to 35% by weight, and particularly preferably from 10 to 35% by weight.

Further, the composition ratio of the filler in the total composition is 9.0
To 23% by weight, and particularly preferably 9.0 to 22% by weight. When the composition ratio of the filler in the entire composition is less than 9.0% by weight, the rigidity of the obtained composition is low. On the other hand, if it exceeds 23% by weight, the rigidity is improved, but the density is increased and the impact resistance is deteriorated.

(G) Production of Composition The composition of the present invention can be produced by uniformly mixing the entire polymer and the filler, and if necessary, is generally used for olefin-based polymers. Additives such as oxygen, light or heat stabilizers, flame retardants, processability improvers, lubricants, antistatic agents, and pigments may be added.

To obtain the composition, dry blending may be performed using a mixer such as a tumbler, ribbon blender and Henschel mixer, or a batch kneader (for example, a Banbury mixer) or a continuous kneader ( For example, kneading can be performed using an extruder. Further, these methods can be used together (for example, dry-blended and then continuously kneaded) to achieve more uniform mixing.

(H) Molding Method Various molded products can be produced by subjecting the composition obtained as described above to thermoforming or injection molding such as hot flow stamping generally performed in the field of polyolefin resins. .

At the time of thermoforming, it depends on the type of each of the above components and the composition ratio thereof, but usually the molding temperature is 190 to 250 ° C.
It is. In the case of injection molding, the molding temperature is generally 200 to 230 ° C.

[Function] In the resin composition of the present invention, the propylene homopolymer and the amorphous ethylene-propylene copolymer, or the composition comprising these polymers and the filler are mixed with the propylene-ethylene random copolymer or the non-crystalline copolymer. When each of the fixed-form ethylene-propylene copolymers is independently blended, the induction time until the start of crystallization, that is, the nucleus start time (τ) can be reduced. However, a resin composition containing only one of these polymers cannot provide satisfactory results in other functions. For example, when only a propylene-ethylene random copolymer is blended, the nucleus initiation time can be lengthened, but the impact strength at low temperature (cold impact strength),
That is, the Izod impact value decreases. On the other hand, when only the amorphous ethylene-propylene copolymer is added, the cold shock resistance is improved, but heat deformation and a decrease in rigidity are not preferred. Although the reason is unknown, when these propylene-ethylene random copolymers and amorphous ethylene-propylene copolymers are used in combination, it is possible to effectively reduce the amount of nucleation by delaying the nucleus initiation time by using each of them independently. Induction time can be reduced.

From these, the induction time until the start of crystallization,
That is, the measurement of the nucleation start time, when performing isothermal crystallization using a scanning differential thermal analyzer and performing stamping molding of a material with a long induction time until the start of crystallization at that time,
It was found that good results of the surface appearance were obtained. In the evaluation, if the Aurenius plot is performed at a temperature at which the induction time is rapidly cooled, the induction time at a temperature corresponding to the mold can be estimated. The material can be determined based on the length of time at that time.

The density of the resin composition of the present invention is 0.96 to 1.05, and is therefore lightweight. Further, the flexural modulus (measured according to JIS K7113) is 19,000 to 28,000 kg / cm ² , indicating high rigidity. For these reasons, the specific elastic modulus (flexural modulus / density) is relatively high, and it is promising as an interior material for automobiles.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

In Examples and Comparative Examples, the nucleation onset time (τ) was measured by using a scanning differential calorimeter as described above until the isothermal crystallization was reached. The Izod impact strength is AS
Measured at 23 ° C with notch according to TM D256. The flexural modulus was measured according to ASTM D790. Further, the heat distortion temperature was measured at a load of 4.6 kg / cm ² (66 psi) according to ASTM D648.

In the examples and comparative examples, a quarter trim (projected area of about 2000 cm) was formed using a known stamping molding machine whose plan view is shown in FIG. 1 and whose side view is shown in FIG.
² ) Stamping molding was performed under the conditions of a resin temperature of 200 ° C. and a molding pressure of 50 kg / cm ² . 1 and 2, 1 is an extruder, 1a is a nozzle, 2 is a measuring section, 3 is a hopper, 4
Is a moving table, 6 is a cylinder, 7 is a hydraulic pump, 8 is a press machine, 8a is a lower mold of the press machine, 8b is an upper mold, and 9 is a control panel.

In the stamping molding machine, the resin composition filled in the hopper 3 is measured by the measuring section 2 of the extruder 1, positioned by the moving table 4, and extruded from the nozzle 1a through the cylinder 6 driven by the hydraulic pump 7. And
A predetermined amount is extruded into the lower die 8a of the press machine 8. The extruded resin composition is pressed by the lower die 8a and the upper die 8b of the press machine 8. In these operations, the control panel 9 controls the temperature, pressure, and the like.

Further, the injection molding is performed by using a mold having a size similar to that of the forter trim formed by the stamping molding and having a similar shape, using an injection molding machine having a mold clamping pressure of 1300 tons, and a mold temperature of 40. C. and a resin temperature of 200 ° C.

In Examples and Comparative Examples, the propylene homopolymer and the ethylene-propylene random copolymer used were each subjected to homopolymerization of propylene in a polymerization reactor using a Ziegler-Natta catalyst without using a solvent. Then, ethylene was fed into the polymerization vessel, and each mixture was produced by copolymerizing ethylene and propylene. All the propylene homopolymers in the obtained mixture had a content of 0% soluble in xylene at a temperature of 30 ° C., and the ethylene-propylene random copolymer was none of them.
At a temperature of 30 ° C., the content insoluble in xylene was 0%.
Ethylene in each of the resulting mixtures (I), (II) and (III)
Mixing ratio of propylene random copolymer (component B), MFR of propylene homopolymer (component A) and M of total mixture
Table 1 shows FR.

Further, as the propylene-ethylene random copolymer, a propylene-ethylene random copolymer having an ethylene copolymerization ratio of 2.5% by weight and an MFR of 50 g / 10 minutes was used. Further, as an amorphous ethylene-propylene copolymer, the copolymerization ratio of propylene is 28% by weight, the Mooney viscosity (ML _{1 + 4} , 100 ° C.) is 35, and the crystallinity is 0%.
The amorphous ethylene-propylene copolymer was used. Talc having an average particle size of 2 μm was used as a filler.

Examples 1 to 7, Comparative Examples 1 to 7 Mixtures (I), (II) and (III) shown in Table 1 [Comparative Example 7 is a propylene homopolymer having an MFR of 50 g / 10 minutes (hereinafter referred to as “PP”). Examples) and Comparative Examples were prepared by mixing propylene-ethylene random copolymer (component C), amorphous ethylene-propylene copolymer (component D) and talc in proportions shown in Table 2. Raw material.

These mixtures were dry-blended in advance using a Henschel mixer for 5 minutes. Each of the obtained mixtures was melt-kneaded at a resin temperature of 230 ° C. using an extruder having a biaxial screw (diameter 45 mm, length 1350 mm, 30 pitch) in the same direction. Each composition (pellet) thus obtained was subjected to isothermal crystallization using a scanning differential analyzer. As described above, the quenching temperature of the isothermal crystallization is measured at three or more points to measure the induction time until the onset of crystal nuclei, and the Aurenius plot is taken of the reciprocal of the quenching temperature (absolute temperature). The induction time until the start of crystallization at the mold temperature is calculated. The quenching temperature was 115 ° C.

Each of the obtained compositions was injection-molded at a resin temperature of 230 ° C., and test pieces for measuring Izod impact strength and flexural modulus were manufactured, and their physical properties were measured. Also,
The specific gravity and MFR of the composition were measured. Further, the specific elastic modulus is obtained by calculation from the bending elastic modulus and the specific gravity, and each composition is subjected to hot flow stamping molding under the above conditions, the forter trim is molded, the external appearance is visually observed, and the whole is observed. The results are shown in Table 3.

In Table 3, ○ indicates good appearance and X indicates bad appearance.

From the results of Comparative Example 7, when the ethylene-propylene random copolymer was not blended, the impact resistance (including the cold impact resistance) was low.

[Effects of the Invention] The resin composition of the present invention can be injection-molded as well as hot-flow stamping-molded, and exhibits the following effects, including the molded product obtained.

(1) Knit by hot flow stamping molding,
When molded integrally with the surface of a polyvinyl chloride resin leather or moquette, etc., and bonded to the surface, the cooling rate of the side where the surface is bonded to the resin composition and the side that is directly contacted with the mold are cooled. Since the difference is relatively small, warpage of the obtained product is small.

(2) It has a small specific gravity and is suitable for weight reduction of parts.

(3) Even when hot flow stamping molding is performed, the molded product obtained does not have any cooling marks as in the case of injection molding.
Its surface is almost the same.

(4) Good cold shock resistance.

(5) Excellent rigidity (flexural modulus).

(6) Good heat resistance.

(7) Excellent moldability.

The resin composition of the present invention can be used in various fields by injection molding, hot flow stamping molding and the like. Typical applications include automotive interior components such as trunk trim, door trim, pillars, quarter trim, instrument panel shelves, instrument panel sesties, armrests, and the like.

[Brief description of the drawings]

FIG. 1 is a plan view of an apparatus for performing stamping molding in Examples and Comparative Examples, and FIG. 2 is a side view of the apparatus. 1 ... Extruder, 1a ... Nozzle, 2 ... Measuring unit, 3 ... Hopper, 4 ... Movable table, 6 ... Cylinder, 7 ... Hydraulic pump, 8 ... Breath machine, 8a ... Die, 8b ... Upper die, 9 ... Control panel.

Continued on front page (72) Inventor Satoru Omura 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Teruo Hosokawa 3-2 Chidoricho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa Denko Co., Ltd. Inside the laboratory (72) Inventor Hiroshi Shibano 3-2 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa Denko Co., Ltd.Kawasaki Resin Research Laboratory (72) Inventor Hiromitsu Gomitsu 4-7-23 Nakamura-ku, Nagoya-shi, Aichi Prefecture Nagoya Branch Co., Ltd. (72) Inventor Akira Nakatani 1-13-9 Shibadaimon, Minato-ku, Tokyo Showa Denko KK (56) References JP-A-1-197544 (JP, A) JP-A-1-247441 (JP, A) JP-A-61-247747 (JP, A) JP-A-58-84838 (JP, A)

Claims (1)

(57) [Claims] (A) a propylene homopolymer having a xylene-soluble content of at most 5.0% by weight at a temperature of 30 ° C., and (B) a xylene-insoluble content of at most a temperature of 30 ° C.
5.0% by weight, and the copolymerization ratio of propylene is 30 to 7
(C) ethylene-propylene random copolymer having a copolymerization ratio of ethylene of 1.0 to 10% by weight, (D) Mooney viscosity [ML _{1 + 4} , (100 (C) is from 20 to 100, and an amorphous ethylene-propylene copolymer having a propylene content of less than 20 to 30% by weight, and (E) a filler. The composition ratio of the filler is 9.0
~ 23 wt%, the composition ratio of the ethylene-propylene random copolymer in the total amount of the propylene homopolymer and the ethylene-propylene random copolymer is 5.0
-30% by weight, the melt index of the total of these polymers is 2.0-200 g / 10 minutes, and propylene homopolymer, ethylene-propylene random copolymer, propylene-ethylene random copolymer and amorphous ethylene −
The propylene homopolymer and the ethylene-propylene random copolymer account for 40 to 80% by weight of the total amount of the total amount of all the polymers composed of the propylene copolymer, and The composition ratio of the propylene-ethylene random copolymer occupying is less than 30% by weight, but the composition ratio of the propylene homopolymer and the ethylene-propylene random copolymer to 1 part by weight of the propylene-ethylene random copolymer is the sum of them. As quantity
More than 2.5 parts by weight, but at most 9.0 parts by weight, and the composition ratio of the amorphous ethylene-propylene copolymer in the total polymer is at least 5.0% by weight, but the amorphous ethyne-propylene copolymer And a resin composition in which the composition ratio of the ethylene-propylene random copolymer is at most 40% by weight in total.