JP2902718B2 - 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, thermoforming such as hot flow stamping can not only produce a molded product having a surface appearance similar to that obtained by injection molding, but also has extremely excellent rigidity and light weight. It relates to a certain resin composition.

[Conventional technology]

Currently, propylene-based polymer (polypropylene resin)
Is not only excellent in various mechanical properties, but also has good molding processability and is relatively chemically stable, so it can be applied to various automotive parts by molding methods such as hot flow stamping molding and vacuum molding. Widely molded. However, when manufacturing by hot flow stamping molding method, when filling the molten material into the mold, the temperature difference between the mold and the resin causes uneven cooling, which lowers the product value and uses only the functional material. It is not at the moment. For this reason, a product having a surface appearance comparable to a molded product obtained by the injection molding method has not been obtained so far.

Furthermore, the polypropylene 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. For this purpose, it has been proposed to improve the flexural modulus by adding a filler to the ethylene-propylene block copolymer and the ethylene-propylene copolymer rubber (see, for example, Japanese Patent Application Laid-Open No. 58-1983).
111846, 57-73034, 57-159841, 63-434
No. 2).

Further, the applicant has proposed that a composition suitable for a bumper is (A) a propylene homopolymer and / or a propylene-ethylene random copolymer, (B) an ethylene-propylene random copolymer, and (C) an ethylene-propylene copolymer. And (D) a propylene-based polymer composition comprising talc which has been previously proposed (Japanese Patent Application No. 1-203898).
issue).

[Problems to be solved by the invention]

However, for the composition for bumpers,
All have good impact strength, especially at low temperatures (for example, 0 to -40 ° C). Moreover, in the invention proposed by the applicant before, the adhesion of the urethane paint is good, and the gasohol resistance is also excellent. However, the stiffness is not always satisfactory (ie, the flexural modulus is low).

Furthermore, in improving the molten material by hot flow stamping molding, in order to improve the material, since the polypropylene resin is a crystalline material, a method of suppressing cooling unevenness when the polypropylene resin melted on the mold is solidified. The following three methods are conceivable.

(1) Method for slowing down the crystallization rate (2) Decreasing the degree of crystallinity (3) Slowing down the induction time until crystallization starts Means that the cooling of the polypropylene resin is delayed, and the molding cycle becomes long, which is not economical. Also, lowering the crystallinity is
It is not advisable to reduce the mechanical strength of the material and narrow the value and application of the function itself.

From the above, the present invention is one of the above three methods,
Not only is the induction time until the onset of crystallization very slow (increases the induction time), but it is also particularly lightweight,
Another object is to obtain a material having extremely excellent rigidity.

[Means and actions for solving the problem]

According to the present invention, these problems are: (A) at 30 ° C. the xylene solubles are at most 5.
0% propylene homopolymer; (B) a xylene-soluble component at a temperature of 30 ° C. of at most 5.
0% and an ethylene-propylene random copolymer having a propylene copolymerization ratio of 25 to 75% by weight; (C) a propylene-ethylene random copolymer having an ethylene copolymerization ratio of 1.0 to 10% by weight (D) the copolymerization ratio of propylene is 15 to 40% by weight,
And a melt index [first according to JIS K 7210]
The condition of the table was measured at 14, hereinafter referred to as `` MFR '') is 0.01 to 10 g
/ 10 min, with a melting peak of 8 measured with a differential scanning calorimeter.
0 ° C. or higher, the degree of crystallinity measured by X-ray is 3% or higher, and the weight average molecular weight / number average molecular weight which is an index of the molecular weight distribution measured by gel permeation chromatography is 4 or higher. A composition comprising a propylene copolymer and (E) a filler, wherein the composition ratio of the filler in the composition is
7.0 to 25% by weight, 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, and the total MFR of these polymers is 2.
0 to 100 g / 10 minutes, and the total of "propylene homopolymer, ethylene-propylene random copolymer, propylene-ethylene random copolymer and ethylene-propylene copolymer" (hereinafter referred to as "all polymer") The composition ratio of the total of the propylene homopolymer and the ethylene-propylene random copolymer in the total amount is 5 to 60% by weight, and the composition ratio of the propylene-ethylene random copolymer in the total amount of all the polymers. Is more than 65% by weight, and the composition ratio of the propylene homopolymer and the ethylene-propylene random copolymer to 100 parts by weight of the propylene-ethylene random copolymer exceeds 30 parts by weight as their total amount, but at most 50 parts by weight. Parts by weight, and the composition ratio of the ethylene-propylene copolymer in the total polymer is at least 1.0% by weight. However, the composition ratio of the ethylene-propylene copolymer and the ethylene-propylene random copolymer is at most 20% by weight as their total amount.
It can be solved by the following resin composition. Hereinafter, the present invention will be described specifically.

(A) Propylene homopolymer The propylene homopolymer used in the present invention is 30 ° C.
At most 5.0 x
% By weight (preferably 3.0% by weight or less). The MFR of the polymer is generally 2.0 to 100 g / 10
Min, preferably between 5.0 and 100 g / 10 min, especially
Those with 5.0 to 80 g / 10 minutes are preferred. If a propylene homopolymer having an MFR of less than the lower limit is used, the kneading property is not good and the composition is not good in moldability. On the other hand, when the ratio exceeds the upper limit, 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 25 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 25% by weight is used, the impact resistance of the composition is poor. On the other hand, an ethylene-propylene random copolymer having a propylene copolymerization ratio of more than 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 total of the propylene homopolymer and the ethylene-propylene random copolymer
Is 2.0-100 g / 10 min, preferably 5.0-100 g / 10 min,
Particularly, 5.0 to 80 g / 10 minutes is preferable. 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 100 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 a copolymerization ratio of ethylene of 1.0 to 10% by weight,
1.5 to 8.0% by weight is desirable, and especially 2.0 to 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, 10
If the content is more than 10% by weight, 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) Ethylene-propylene copolymer The ethylene-propylene copolymer used in the present invention has a copolymerization ratio of propylene of 15 to 40% by weight, preferably 18 to 40% by weight, particularly preferably 20 to 38% by weight. % Is preferred. When an ethylene-propylene copolymer having a propylene copolymerization ratio of less than 15% by weight is used, the effect of improving the impact resistance of the obtained composition is poor. On the other hand, when the ethylene-propylene copolymer exceeds 40% by weight, the effect of improving the impact resistance of the obtained composition is good, but other mechanical properties (for example, rigidity) are poor.

Further, the MFR of the ethylene-propylene copolymer is 0.01
To 10 g / 10 min, preferably 0.02 to 10 g / 10 min, and particularly preferably 0.05 to 8.0 g / 10 min. If an ethylene-propylene copolymer having an MFR of less than 0.01 g / 10 minutes is used, the resulting composition has poor processability. On the other hand, when an ethylene-propylene copolymer exceeding 10 g / 10 minutes is used, the effect of improving the impact resistance of the obtained composition is not good.

Mooney viscosity of the ethylene-propylene copolymer (ML
_{(1 + 4} , 100 ° C.) is usually from 10 to 150, preferably from 10 to 130, particularly preferably from 10 to 120. If an ethylene-propylene copolymer having a Mooney viscosity of less than 10 is used, the moldability is improved, but the effect of improving impact properties is low,
Layer delamination may occur at the time of gate cutting of a molded product, which may cause trouble. On the other hand, if an ethylene-propylene copolymer exceeding 150 is used, not only dispersion during kneading becomes difficult, but even if a uniform composition is obtained, a flow mark on the surface of the molded product,
Weld lines and the like become noticeable, and a molded article with good appearance cannot be obtained.

Incidentally, the ethylene-propylene copolymer is usually used as a differential scanning calorimeter (DS).
The melting peak measured in C) is 80 ° C. or more, and the crystallinity measured by X-ray is 3% or more. Melting peak is 80
To 125 ° C is preferred, and 85 to 125 ° C is particularly preferred. If the melting peak is lower than 80 ° C., the resulting composition has poor rigidity and tensile strength. The ethylene-propylene copolymer has a crystallinity of 3% or more as measured by X-ray,
-30% is desirable, and 3-25% is particularly preferable. When an ethylene-propylene copolymer having a crystallinity of less than 3% is used, rigidity and tensile strength are poor. on the other hand,
If the content exceeds 30%, the impact resistance is not good.

Further, the ethylene-propylene copolymer has a weight average molecular weight ( _w ) / number average molecular weight ( _n ), which is an index of a molecular weight distribution measured by gel permeation chromatography (GPC), of 4 or more. preferable. _w
If an ethylene / propylene copolymer having an / _n of less than 4 is used, the resulting composition has poor processability.

(E) Filler The filler used in the present invention is generally widely used in the synthetic resin and rubber fields.
Among these fillers, inorganic fillers that do not react with oxygen and water and do not decompose during kneading and molding are preferably used as the inorganic filler. 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. , Sulfate,
Compounds such as carbonates and silicates, double salts thereof, and mixtures thereof are roughly classified. Representative examples of the inorganic filler are described in Japanese Patent Application No. 59-8535. Among these inorganic fillers, powdery ones having a diameter of 30 μm or less (preferably 10 μm or less) are preferable. In the case of a fibrous material, the diameter is 1 to 500 μm (preferably 1 to 300 μm)
It is desirable that the length is 0.1 to 6 mm (preferably 0.1 to 5 mm). Further, it is preferable that the flat plate has a diameter of 30 μm or less (preferably 10 μm or less). Among these inorganic fillers, those in the form of a plate (flake) and those in the form of powder are particularly preferred. Suitable inorganic fillers include
Examples include talc, mica, silica, glass fiber, graphite and the like.

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

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

The organic fibers are animal fibers such as wool, vegetable fibers such as cotton, jude, 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 the 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, Length of 0.1
A size of about 6 mm is appropriate.

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.

Moreover, hulls and peanuts are used after being crushed like the wood flour.

(F) Composition Ratio In the 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, ~ 27% by weight is preferred,
7.0-27% 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. On the other hand, when the content exceeds 30% by weight, the rigidity of the composition decreases.

Further, propylene homopolymer, ethylene-propylene random copolymer, propylene-ethylene random copolymer and ethylene-propylene copolymer (that is,
The composition ratio of the propylene homopolymer and the ethylene-propylene random copolymer in the total polymer) is 5 to 60.
%, Preferably 8 to 50% by weight, more preferably 10 to 50% by weight.
40% by weight is preferred. If the composition ratio of the propylene homopolymer and the ethylene-propylene random copolymer in the total polymer is less than 5% by weight, the resulting composition has poor impact resistance. On the other hand, if it exceeds 60% by weight, sink and deformation are large when forming a thick molded product, and the appearance and shape are not good.

Further, the composition ratio of the propylene-ethylene random copolymer in the total polymer exceeds 65% by weight. More than 65% by weight, preferably 80% by weight or less, more than 65% by weight, but preferably 75% by weight or less. When the copolymerization ratio of the propylene-ethylene random copolymer in the total polymer is less than 65% by weight, the obtained composition cannot be delayed so as to satisfy the induction time until crystallization of the composition starts. On the other hand, if it exceeds 80% by weight, the obtained rigidity is low.

Further, the composition ratio of the propylene homopolymer and the ethylene-propylene random copolymer relative to 100 parts by weight of the propylene-ethylene random copolymer exceeds 30 parts by weight as their total amount, but at most 50 parts by weight,
30 to 45 parts by weight are desirable, and 32 to 45 parts by weight are particularly preferred. The composition ratio of the propylene homopolymer and the ethylene-propylene random copolymer to 100 parts by weight of the propylene-ethylene random copolymer is 30 in total.
When the amount is less than the weight part, the nucleus start time is short, the appearance is deteriorated, and the rigidity is reduced. On the other hand, if it exceeds 50 parts by weight, the impact resistance is significantly reduced, and the creep strength at high temperatures is reduced.

Further, the composition ratio of the ethylene-propylene copolymer in the total polymer is at least 1.0% by weight. However, if it exceeds 15% by weight, the moldability of the resulting composition is not satisfactory. From these facts, the composition ratio of the ethylene-propylene copolymer in the whole polymer is preferably 1 to 12% by weight, and particularly preferably 3 to 12% by weight.

Further, the composition ratio of the ethylene-propylene copolymer and the ethylene-propylene random copolymer in the total polymer is such that the total amount (sum) of the obtained compositions is large as the total amount thereof from the viewpoint of heat resistance and rigidity. 20% by weight
It is. However, when the composition ratio of these polymers in the total polymer is less than 20% by weight as the total amount of the polymers, the nucleation initiation induction period is short, cooling unevenness easily occurs, and the appearance is poor. From these facts, the total composition of the ethylene-propylene copolymer in the total polymer is preferably 1 to 15% by weight, more preferably 2 to 10% by weight.

Further, the composition ratio of the filler in the total composition is 7.0
To 25% by weight, preferably 7.0 to 23% by weight, particularly 8.0%
~ 23% by weight is preferred. When the composition ratio of the filler in the entire composition is less than 7.0% by weight, the rigidity of the obtained composition is low. On the other hand, if it exceeds 25% by weight, the rigidity is improved but the density is also increased. In addition, impact resistance is deteriorated.

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

The composition may be dry blended using a mixer such as a tumbler, ribbon blender and Henschel mixer, or may be a batch kneader (eg, a Banbury mixer) or a continuous kneader (eg, an extruder). Can be kneaded using a continuous mixer, as described above. In addition, these methods are used in combination (for example, kneading continuously after dry blending).
By doing so, it can be mixed more uniformly.

(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 the usual molding temperature is 190 to 250.
° C. In the case of injection molding, the molding temperature is generally 200 to 230 ° C.

[Action]

In the resin composition of the present invention, the propylene homopolymer and an ethylene-propylene copolymer, or a composition comprising these polymers and a filler, the propylene-
Even if each of the ethylene random copolymer and the ethylene-propylene copolymer is independently blended, the induction period up to the start of crystallization, that is, the nucleus start time (τ) can be delayed. However, a resin composition containing any of these polymers cannot provide satisfactory results in other functions. For example, when only a propylene-ethylene random copolymer is blended, the nucleation start time can be lengthened,
The impact strength at low temperatures (cold impact strength), that is, the Izod impact value, is low. On the other hand, when only the ethylene-propylene copolymer is added, although the cold impact resistance is improved, it is not preferable because heat resistance deformation and rigidity decrease are caused. The reason is unknown, but when these propylene-ethylene random copolymers and ethylene-propylene copolymers are used in combination, the nucleation start time is effectively slowed down with a smaller amount of blending than when each is independently blended and the nucleation start time is delayed. be able to.

In particular, in the present invention, the nucleus initiation time can be greatly delayed by blending a relatively large amount of the propylene-ethylene random copolymer. This means
For thick molded products, dimensional accuracy is greatly affected by sinks and warpage of the molded products. In particular, when the skin is integrally formed with the thick molded product, the skin is hardly cooled, and the tendency of sink and warp is remarkable. It is effective in improving it.

From these, the induction period leading to the start of crystallization,
In other words, the measurement of the nucleation start time is performed by isothermal crystallization using a scanning differential thermal analyzer and, when hot flow stamping molding of a material having a long induction time until crystallization is started is performed, the surface appearance is good. It turned out that a good result was obtained. In the evaluation, if the Aurenius plot is performed at the temperature at which the time of the induction period is rapidly cooled, the induction period at the 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 K 7113) is 19,000 to 28,000 kg / cm ² , and the rigidity is high. From these facts, the specific elastic modulus (flexural modulus / density) is relatively high, and it is considered to be promising as an interior material for automobiles.

[Examples and Comparative Examples]

Hereinafter, the present invention will be described in more detail with reference to 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 according to TM D256 at 23 ° C. with notch. 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 Examples and Comparative Examples, a rear parcel self (projected area 2, 2) was used by using a hot flow stamping molding machine shown in a plan view in FIG. 1 and a side view in FIG.
800cm ² ) The resin temperature is 200 ℃ and the molding pressure is 50kg / cm ²
Hot flow stamping molding was performed under the following conditions. First
In FIG. 2 and FIG. 2, 1 is an extruder, and 1a is a nozzle. Reference numeral 2 denotes a measuring unit, and reference numeral 3 denotes a hopper. Further, 4 is a moving table and 6 is a cylinder. Reference numeral 7 denotes a hydraulic pump, and reference numeral 8 denotes a press. 8a is a lower die of the press machine, and 8b is an upper die. 9 is a control panel. In the hot flow stamping molding machine whose plan view is shown in FIG. 1 and whose side view is shown in FIG. 2, the resin composition filled in the hopper 3 is measured by the measuring section 2 of the extruder 1,
It is pressurized by the hydraulic pump 7, passes through the cylinder 6,
It is extruded at 1a and is extruded at a constant rate into the lower die 8a of the press machine 8. The resin composition extruded here is the lower mold of the press machine 8.
Pressed by 8a and upper die 8b. Note that these operations are
The control panel 9 controls temperature, pressure, and the like.

In addition, the injection molding uses a mold having a size similar to that of the rear parcel self molded by the hot flow stamping molding and having a similar shape, using an injection molding machine having a mold clamping thickness of 1300 tons. The test was performed at a temperature of 40 ° C. and a resin temperature of 200 ° C.

The appearance was subjected to hot flow stamping molding by the method described above, and the appearance of the obtained rear parcel self is shown in Table 3 in the same degree as that of injection molding, which is best "◎", good "○", gloss at vacuum molding temperature A sample without a mark was indicated by "△", a sample with a worse case was indicated by "x", and a sample with noticeable cooling marks was indicated by "xx".

In the 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 a copolymer of ethylene and propylene was produced to produce each mixture. 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%.
The mixing ratio of the ethylene-propylene random copolymer (hereinafter, referred to as "component B") in each of the obtained mixtures, the MFR of the propylene homopolymer (hereinafter, referred to as "component A") and the MFR of the whole mixture were defined as the first. It is shown in the table.

Further, as a propylene-ethylene random copolymer, the copolymerization ratio of ethylene was 2.5% by weight, and the MFR was 50%.
A propylene-ethylene random copolymer having a g / 10 minutes was used. Further, as the ethylene-propylene copolymer, the copolymerization ratio of propylene is 38% by weight, the Mooney viscosity (ML _{1 + 4} , 100 ° C.) is 42, and the MFR is 2.5 g / 10
Min, melting point of 105 ° C and crystallinity of 4%
And an ethylene-propylene copolymer having a w / n of 5.0 was used. Also, as talc, the average particle size is 2
A talc of μm was used.

Examples 1 to 6 and Comparative Examples 1 to 6 [Table 2 shows mixtures in which the mixing ratios are shown. [Comparative Example 7 is a propylene homopolymer having an MFR of 50 g / 10 minutes (hereinafter referred to as “PP”). Use), propylene-
Ethylene random copolymer (hereinafter referred to as "component C"),
The ethylene-propylene copolymer and talc 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: 30 pitch) in the same direction. Isothermal crystallization was determined for each of the resulting components (in the form of pellets) using a scanning differential analyzer. As described above, the quenching temperature of the isothermal crystallization was determined by measuring the induction time until the start of crystallization at three or more temperatures, taking an Aurenius plot 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. Table 3 shows the results. Further, the specific gravity of the composition and
MFR was measured. Table 3 shows the results. Further, Table 3 shows the specific elastic modulus calculated from the bending elastic modulus and the specific gravity.

Further, each composition was subjected to hot flow stamping molding under the above conditions to form the rear parcel self. Table 3 shows their appearance.

In all of the examples, no warpage was observed in the molded product regardless of whether injection molding or stamping molding was performed. On the other hand, in all of the comparative examples, warpage was considerably observed both in the case of injection molding and in the case of hot flow stamping molding.

From the results of Comparative Example 3, when the ethylene-propylene random copolymer was not blended, the impact resistance (including the cold impact resistance) was low.

〔The invention's effect〕

The resin composition of the present invention is not only capable of being injection-molded, but also hot-flow stamping-molded, and can exhibit the following effects, including the molded product obtained.

(1) Knit by hot flow stamping molding,
When molded integrally with the skin of leather, moquette, etc. of polyvinyl chloride resin and bonded to the skin, the cooling rate of the side where the skin and the resin composition are bonded and the side that is directly cooled by contacting the mold are different. 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, rear parcel shelves, instrument panel shelves, instrument panel sesties, and armrests.

[Brief description of the drawings]

FIG. 1 is a plan view of an apparatus for hot flow stamping molding in Examples and Comparative Examples, and FIG. 2 is a side view of the apparatus. DESCRIPTION OF SYMBOLS 1 ... Extruder, 1a ... Nozzle 2 ... Measuring part, 3 ... Hopper 4 ... Moving table, 6 ... Cylinder 7 ... Hydraulic pump, 8 ... Press machine 8a ... Lower die, 8b ... Upper die 9 ... Control panel

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-221142 (JP, A) JP-A-3-163143 (JP, A) JP-A-3-290454 (JP, A) JP-A-3- 121147 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08L 23/04-23/16

Claims (1)

(57) [Claims] (A) a propylene homopolymer having a xylene-soluble content of at most 5.0% at a temperature of 30 ° C .; and (B) a xylene-insoluble content of at most 5.% at a temperature of 30 ° C.
0% and an ethylene-propylene random copolymer having a propylene copolymerization ratio of 25 to 75% by weight; (C) a propylene-ethylene random copolymer having an ethylene copolymerization ratio of 1.0 to 10% by weight (D) the copolymerization ratio of propylene is 15 to 40% by weight,
And a melt index of 0.01 to 10 g / 10 min, a melting peak measured by a differential scanning calorimeter of 80 ° C. or more, and X
An ethylene-propylene copolymer having a crystallinity of 3% or more as measured by a line and a weight average molecular weight / number average molecular weight of 4 or more as an index of the molecular weight distribution measured by gel permeation chromatography; A) a filler, wherein the composition ratio of the filler in the composition is
7.0 to 25% by weight, 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, the total melt index of these polymers is 2.0 to 100 g / 10 minutes, and propylene homopolymer, ethylene-propylene random copolymer, propylene-ethylene random copolymer and ethylene- The composition ratio of the total composition of the propylene homopolymer and the ethylene-propylene random copolymer in the total amount of all the polymers composed of the propylene copolymer is 5 to 60% by weight,
The composition ratio of the propylene-ethylene random copolymer in the total amount of all the polymers exceeds 65% by weight, but the propylene homopolymer and the ethylene-propylene random copolymer are based on 100 parts by weight of the propylene-ethylene random copolymer. Although the composition ratio of the coalesce exceeds 30 parts by weight as their total amount, it is at most 50 parts by weight, and the composition ratio of the ethylene-propylene copolymer in the total polymer is at least 1.0% by weight. A resin composition in which the composition ratio of the ethylene-propylene copolymer and the ethylene-propylene random copolymer is at most 20% by weight in total.