JP2000302918A - Thermoplastic elastomer composition for slash molding and slash molded skin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition for slash molding retaining 20 g/10 minutes at 230 deg.C under 2.16 kg loading of MFR(melt flow rate), excellent in sheet property in slash molding and a slash molded skin having improved feeling by decreasing hardness, excellent in initial physical properties and retention of physical properties after heat aging. SOLUTION: This thermoplastic elastomer composition for slash molding comprises at least a hydrogenated styrene butadiene random copolymer, a crystalline polypropylene resin, an internal mold release agent, an elastomer excellent in oil absorbing properties, a process oil and an amorphous polypropylene resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition for slush molding and a slush molded skin, and more particularly, to a thermoplastic elastomer composition for slush molding capable of maintaining powder fluidity regardless of the number of moldings.
In addition, the present invention relates to a slush-molded skin that does not change its surface state due to heat aging.

[0002]

2. Description of the Related Art As a powder molding method using a soft powder material, a powder slash molding method using a soft vinyl chloride resin powder is used for an instrument panel, a console box,
Widely used for the skin of car interior parts such as door trim. This is a soft touch, and can be provided with leather grain and stitches, and has good design properties such as a large degree of freedom in design.

[0003] Unlike other molding methods such as injection molding and compression molding, this molding method does not apply a shaping pressure. Therefore, in order to uniformly adhere a powder material to a mold having a complicated shape at the time of molding, powder molding is performed. It is necessary to have excellent fluidity, and a condition that the melt viscosity is low is also required in order for the powder attached to the mold to melt and flow even under no pressure to form a film. In addition, it was necessary that the skin formed by cooling the mold could be released more easily than the mold.

As one method for improving this, Japanese Patent Application Laid-Open No. 11-00723 and Japanese Patent Application No. 10-324801 are disclosed.
Japanese Patent Application Laid-Open Publication No. H11-163873 proposes that a composition obtained by mixing a polypropylene resin, a hydrogenated styrene-butadiene random copolymer rubber, a process oil, and an ethylene / octene copolymer having a long-chain branched structure is ground and used.

[0005]

Since powder slush molding is a special molding method in which powder is adhered and melted to a heated mold to form a film, the powder itself is required to have extremely high melt fluidity. Is done. Therefore, the composition used for slush molding as described above improves the melt fluidity, so that the polypropylene resin component is decomposed with an organic peroxide or the like to increase the fluidity, and the elastomer component is paraffin-based. The addition of oils and the like increases the fluidity, thereby increasing the melt fluidity of the entire composition.

[0006] Further, since the polypropylene resin component has higher fluidity than the elastomer component, increasing the polypropylene resin component increases the melt fluidity of the entire composition. On the other hand, when the polypropylene resin component increases, the slush-molded skin itself becomes thin. Because it is hard, the touch is very poor. When the amount of the elastomer component (hydrogenated styrene-butadiene random copolymer rubber) is increased, the hardness is reduced and the feel is improved, but the fluidity is considerably deteriorated.

[0007] In order to compensate for the decrease in fluidity due to the increase in the elastomer component, there is a method of increasing the amount of the paraffin-based oil. However, if the amount of the paraffin-based oil is too large, the oil-absorbing elastomer retains the paraffin-based oil. Bloom occurs without being able to do so, and gloss and adhesion occur on the surface of the epidermis. On the other hand, when the amount of the oil-absorbing elastomer added is increased, the melt fluidity deteriorates.

When the amount of the paraffin-based oil or the oil-absorbing elastomer is increased, the initial physical properties are reduced, and the physical property retention during heat aging is also deteriorated. Had limitations.
Due to such restrictions, while maintaining the melt fluidity,
It was difficult to reduce the hardness.

The present invention has been made to solve such a problem, and has a good sheet property at the time of slash.
C., a thermoplastic elastomer composition for slush molding maintaining an MFR (melt flow rate) value of 20 g / 10 minutes under a load of 2.16 kg and a reduced hardness to improve the tactile sensation, and to maintain initial physical properties and after heat aging. An object of the present invention is to provide a slush-molded skin having good physical property retention.

[0010]

That is, according to the first aspect of the present invention, at least a hydrogenated styrene-butadiene random copolymer rubber, a crystalline polypropylene resin, an internal mold release agent, an elastomer excellent in oil absorption, and a process are provided. A slush molding thermoplastic elastomer composition containing an oil and an amorphous polypropylene resin. Since slush molding requires high melt fluidity, the amorphous polypropylene resin has a melt viscosity of 300 to 1 at 190 ° C.
A 0000 cp homopolymer or a copolymer with an α-olefin is preferred. The thermoplastic elastomer composition for slush molding has an MFR of 230 ° C. and 2.16 k.
The slush-molded skin obtained by slush-molding this powder has a reduced hardness and an improved tactile sensation, and has excellent physical properties even after initial physical properties and heat aging.

According to the invention of claim 2 of the present application, the amorphous polypropylene resin has a melt viscosity at 190 ° C. of 300.
A thermoplastic elastomer composition for slush molding, which is an amorphous polypropylene resin that is a homopolymer of 10000 cp or a copolymer with an α-olefin.

According to the third aspect of the present invention, there is provided a thermoplastic elastomer composition for slush molding to which an organic peroxide is added.

According to the invention of claim 4 of the present application, there is provided a thermoplastic elastomer composition for slush molding, wherein the elastomer having excellent oil absorbing ability is an ethylene-octene copolymer having a long-chain branched structure.

In the invention according to claim 5 of the present application, at least hydrogenated styrene-butadiene random copolymer rubber;
Crystalline polypropylene resin, internal release agent, elastomer with excellent oil absorption, process oil, and slush molded skin obtained by slush molding using a thermoplastic elastomer composition to which amorphous polypropylene resin is added,
By lowering the hardness, the feel is improved, and the physical property retention rate becomes good even after the initial physical properties and after heat aging.

According to the invention of claim 6 of the present application, the amorphous polypropylene resin has a melt viscosity at 190 ° C. of 300.
It is a slush-molded skin that is an amorphous polypropylene resin that is a homopolymer of 10000 cp or a copolymer with an α-olefin.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The crystalline polypropylene resin used in the present invention may be any of a polypropylene homopolymer, a block with an α-olefin or a random copolymer. A random copolymer is preferred from the viewpoint of the flexibility of the molded article. For use in powder slush molding without applying pressure, the MFR measured at 230 ° C. under a load of 2.16 kgf according to JIS K7210 as an index of the melt fluidity of the crystalline polypropylene resin is used.
Should be 100 to 800 g / 10 minutes.
The crystalline polypropylene resin having the above MFR value has good melt fluidity, excellent melt fluidity without using an organic peroxide, low melt viscosity, excellent tensile strength,
It is possible to obtain a molded sheet having no sticky gloss due to heat aging.

When a crystalline polypropylene resin having an MFR value of less than 100 g / 10 minutes and lacking melt flowability is used, 0.02-5.0 parts by weight of an organic peroxide is added, and 120-250 parts by weight is added. By kneading at a temperature of ° C., the molecular weight of the crystalline polypropylene resin can be reduced so that the MFR value becomes 100 to 800 g / 10 minutes.

When a crystalline polypropylene resin having an MFR value of less than 100 g / 10 minutes and lacking in melt flowability is used, an organic peroxide is added to the crystalline polypropylene resin so that the temperature of 120-250 ° C. After melt-kneading at a temperature, H-SBR can be melt-kneaded. HS
When BR and organic peroxide are melt-kneaded at the same time, HS
BR has a low molecular weight and migrates to the surface of the molded sheet, and after heat aging, tackiness and gloss occur on the surface.

As the above-mentioned organic peroxide, usually, rubber,
Diacyl peroxide used for crosslinking of resin,
Peroxyester, diallyl peroxide, di-t
-Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2.5-dimethyl-
2.5-di (t-butylperoxy) -hexane-3,
1,3-bis (t-butylperoxy-isopropyl)
Benzene, 1,1-di-butylperoxy-3,3,5
-Trimethylcyclohexane and the like;
Those having a half-life of 150 to 250 ° C. per minute are preferred.

In the process of kneading the organic peroxide under heating at 120 to 250 ° C., the main chain of the crystalline polypropylene resin is cut to reduce the molecular weight, and the thermoplastic elastomer composition has high melt fluidity. Give it. The addition amount of the organic peroxide in the thermoplastic elastomer composition is from 0.02 to 5.
When the content is 0% by weight and less than 0.02% by weight, the decomposition ability of breaking the main chain of the crystalline polypropylene resin is small, and it becomes impossible to impart high melt fluidity to the thermoplastic elastomer composition. On the other hand, if the content exceeds 5.0% by weight, the decomposition becomes excessive and the mechanical properties such as the tensile strength of the powder molded product are reduced.

Hydrogenated styrene-butadiene random copolymer rubber (H-SBR) has excellent compatibility with crystalline and amorphous polypropylene resins, and becomes flexible when kneaded with the polypropylene resin, and is bent. A thermoplastic elastomer composition which is hardly whitened is obtained. H-SBR
The styrene content is preferably 30% by weight or less, and 5 to 15% by weight is appropriate for obtaining a highly flexible skin. H-SBR is different from SEBS, which is a block copolymer, in that styrene-butadiene rubber in which styrene and butadiene are randomly copolymerized is hydrogenated. A typical example is the Dynalon series, a product made by Nippon Synthetic Rubber Co., Ltd. The mixing amount of the polypropylene resin and H-SBR is 80/20 to 20 / by weight ratio.
80, and when the polypropylene resin increases,
The molded skin becomes harder, while the less it is, the lower the tensile strength.

The amorphous polypropylene resin is mainly composed of a polypropylene polymer having an atactic stereoregularity as a main component, and has a good compatibility with a normal crystalline polypropylene resin (isotactic polypropylene), and a melt viscosity. Also has the effect of lowering. By blending with the crystalline polypropylene resin, there is an effect that the blended composition itself has flexibility.

Further, the crystalline polypropylene resin and the amorphous polypropylene resin have good compatibility, and the H-SBR and the crystalline PP resin also have good compatibility as they are dispersed in several tens of nm particles. Blends form a homogeneous resin matrix and have considerable flexibility.
Since high melt fluidity is required in slush molding, the amorphous polypropylene resin is desirably a homopolymer having a melt viscosity at 190 ° C. of 300 to 10,000 cp or a copolymer with an α-olefin.

Further, in the present invention, the addition of process oil has the effect of lowering the melt viscosity by being absorbed by the elastomer component in the composition, lowering the hardness of the skin, and having flexibility. The above process oils are used for rubber, and include paraffinic, naphthenic,
Although classified as aroma-based, paraffin-based is preferred due to compatibility with the elastomer component. The addition amount is preferably 5 to 200 parts by weight based on 100 parts by weight of the elastomer having excellent oil absorbing ability. If it exceeds 200 parts by weight, the tensile properties are reduced, and if it is less than 5 parts by weight, the melt viscosity does not decrease and the skin becomes hard.

The elastomer having excellent oil absorbing ability is compatible with the polypropylene resin and has a property of absorbing a process oil and an oligomer component in the composition. The elastomer has a styrene / ethylene / butylene / styrene block copolymer (SEBS). ) And styrene-based block copolymer thermoplastic elastomers such as styrene-ethylene propylene-styrene block copolymer (SEPS), olefin crystal / ethylene butylene / olefin crystal block copolymer (CEBC), ethylene propylene rubber (EP
R), and ethylene-octene copolymer (POE).

In particular, the above-mentioned POE is a catalyst mainly composed of a metallocene compound and has one reaction site (single) per molecule (single), and is obtained by using a single-site catalyst in which active species are homogeneous at all sites. Polymer,
It has a long-chain branched structure, narrow molecular weight distribution, uniform composition distribution, and low content of low molecular weight oligomers and waxes. Therefore, when blended with a polypropylene resin, it has a better fluid dispersibility than EPDM (ethylene-propylene-non-conjugated diene copolymer) and has a property of being easily dispersed in a polypropylene resin, making it a material suitable for slush molding. . Further, the POE has a molecular structure different from a linear one polymerized by an ordinary Ziegler-Natta catalyst, for example, a general-purpose ethylene propylene rubber obtained by copolymerizing ethylene and propylene.

The above SEBS is obtained by hydrogenating a styrene-butadiene-styrene block copolymer (SBS), and includes Clayton G series, a product of Ciel Chemical Co., Ltd., and Tuftec H series, a product of Asahi Kasei Corporation. No. In this SEBS, the strength increases as the styrene content increases, but the flexibility decreases. Also,
In the case of the SEBS, the styrene hard segments may be aggregated due to melting at the time of slush molding, and it may be difficult to obtain a smooth sheet-like molded body. Therefore, the styrene content is preferably 40% by weight or less.

SEPS is a hydrogenated styrene / isoprene / styrene block copolymer (SIS).
Septon, a product made by Kuraray Co., is representative. SE
As in the case of BS, the styrene content is preferably 40% by weight or less because the flexibility decreases as the styrene content increases.

The above-mentioned elastomer having excellent oil-absorbing ability is:
Compared with H-SBR, the compatibility with the polypropylene resin is inferior, and when kneaded and added to the polypropylene resin, it is dispersed in a size of μm unit, so that the tensile properties tend to decrease. However, the HS
When BR and process oil are added, H-SBR
Is poor in oil-absorbing ability, so that the oligomer component in the composition migrates (bleeds) to the surface and has tackiness, and the elastomer powder crushed for powder slush molding using this also has tackiness, so it is easy to block. Powder flow,
In addition, the skin also lacks releasability from the mold. When an elastomer having an excellent oil-absorbing ability is added thereto, the bleed can be considerably prevented by absorbing the oligomer component and the oil in the composition.

The amount of the elastomer having excellent oil absorbing ability is 20 to 250 parts by weight based on 100 parts by weight of H-SBR. If the amount is less than 20 parts by weight, the oligomer component and oil in the composition cannot be sufficiently absorbed, and
If the amount exceeds 0 parts by weight, the dispersion with the polypropylene resin becomes poor, and the tensile properties tend to decrease.

As the heat stabilizer, those used for ordinary polyolefins can be used. Generally, phenol and a phosphorus-based antioxidant are used in combination, but are not particularly limited. As the light stabilizer, a hindered amine or benzotriazole type radical scavenger may be used. Organic and inorganic pigments suitable for ordinary olefins are used. Further, a lubricant such as a fatty acid metal salt and a filler such as calcium carbonate and talc are added as required.

The mixture of these compounds is melt-kneaded by the following two methods. (1) MFR (Melt flow rate JIS K721)
0) is added to a crystalline polypropylene resin of 100 to 800 g / 10 min, simultaneously with H-SBR, a process oil, an elastomer having excellent oil absorption, 4% by weight or more of an amorphous polypropylene resin and the like. ~ 250 ° C
, And in this case, no organic peroxide is added.

(2) 0.02 to 5.0 parts by weight of an organic peroxide is added to a crystalline polypropylene resin having an MFR of less than 100 g / 10 min and an elastomer having an excellent oil absorbing ability.
After kneading at a temperature of 0 to 250 ° C, the mixture is further mixed with H-S
There is a method in which BR, process oil, 4% by weight or more of an amorphous polypropylene resin or the like is added and kneaded at a temperature of 120 to 250 ° C.

The additive kneading method is as follows.
Dry blended using a tumbler, Henschel mixer, etc., is supplied from a raw material supply hopper, process oil is injected from a vent port, and melt-kneaded with a twin-screw extruder adjusted to a temperature in a range of 120 to 250 ° C. to form a pellet. Become

In addition, the elastomer component H- is mixed with a kneader, a Banbury mixer or the like, which is an internal mixer.
A process oil is added to an SBR and an elastomer having excellent oil absorbing ability, kneaded and pelletized, and then the pellet is dry-blended with a polypropylene resin to form a pellet.
Pellets can also be formed by melt-kneading with a single-screw or twin-screw extruder whose temperature has been adjusted to 50 ° C.

MFR which is the melt viscosity of the obtained pellet
Is preferably 20 g / 10 min or more at 230 ° C. under a load of 2.16 kgf. If it is less than this, the melt fluidity of the composition tends to be low, and pinholes tend to occur in the skin.

The pellets obtained from the above composition are finely pulverized using an impact type fine pulverizer such as a turbo mill, a pin mill, and a hammer mill. At this time, it is usually frozen and pulverized using liquid nitrogen. Further, depending on the composition, the molten resin can be powderized by spraying or cooling with a spray or disk atomizer. The pulverized product is passed through a sieve having a particle size of at least 1,000 μm by means of a sieve or the like, and those having an average particle size of 100 to 800 μm are collected, and an organic or inorganic powdery improver is added thereto and mixed. And used for powder slush molding.

Next, powder slush molding is performed using the elastomer composition. In this molding, the composition is mainly dropped by gravity and poured into a mold heated to a temperature higher than the melting point of the composition, and after a certain period of time, the mold is inverted and excess composition is collected in a collection box. The composition adheres as a layer to the mold surface, and melts over time to form a skin layer.
Then, the mold is cooled and the skin layer is released,
This is repeated.

The method of heating the mold is generally a method of circulating oil or putting it in a hot blast stove. Oil circulation is easy to adjust the mold temperature by pipe arrangement, but is heated only from the mold surface. On the other hand, if a hot blast stove is used, heating can be performed from both the mold surface and the back surface of the molded product. However, since hot air is often set to 250 ° C. or higher in consideration of productivity, the thermal oxidation It is necessary to consider the prescription and conditions so as not to cause deterioration.

The hot air system is effective when powder slush molding is performed in multiple layers (two or three). That is, the first powder to be the outermost layer is slush-molded in a heated mold,
The powder is deposited a second time in a semi-molten state and, if necessary, slushed a third time, then heat melted. In this case, if the heating is performed only from the mold surface side, the heat transfer is insufficient, so that a hot blast stove method capable of heating from the back surface of the molded product is often used.

[0041]

Next, the present invention will be described in more detail with reference to specific comparative examples and examples.

Comparative Example 1 In Comparative Example 1, a twin-screw extruder (PCM4 manufactured by Ikegai Iron and Steel Co., Ltd.) was used.
In 5), kneading is performed twice. In the first kneading, a twin-screw extruder (PCM4, manufactured by Ikegai Iron and Steel Co., Ltd.) obtained by dry-blending a crystalline polypropylene resin, an elastomer having excellent oil-absorbing ability, an organic peroxide, and a release agent by a tumbler.
The mixture was supplied from the raw material supply hopper of 5), kneaded at 230 ° C. and 100 rpm while the process oil was injected from the vent port, and extruded into pellets.

Subsequently, the pellets produced in the first kneading were dry-blended with H-SBR and a stabilizer by a tumbler, and the resulting mixture was twin-screw extruder (PCM45, manufactured by Ikegai Iron and Steel Co., Ltd.).
Supplied from the raw material supply hopper at 220 ° C, 300r
The mixture was kneaded at pm and extruded into pellets. The pellets obtained above are immersed in liquid nitrogen, and Turbomill T250-4J
(Turbo Kogyo Co., Ltd.) and pulverized to 1,000 μm
Only the fraction passed through the sieve was collected.

Examples 1 to 3 Also in Examples 1 to 3, a twin-screw extruder (PCM, manufactured by Ikegai Iron and Steel Co., Ltd.)
In 45), kneading is performed twice. In the first kneading, a twin-screw extruder (PCM4, manufactured by Ikegai Iron and Steel Co., Ltd.) obtained by dry-blending a crystalline polypropylene resin, an elastomer having excellent oil-absorbing ability, an organic peroxide, and a release agent with a tumbler.
The mixture was supplied from the raw material supply hopper of 5), kneaded at 230 ° C. and 100 rpm while the process oil was injected from the vent port, and extruded into pellets. Subsequently, the pellets produced in the first kneading were dry-blended with a tumbler of H-SBR, an amorphous polypropylene resin, and a stabilizer, and the resulting mixture was fed to a twin-screw extruder (PCM45, manufactured by Ikegai Iron & Steel Co., Ltd., PCM45). Supplied at 220 ° C, 300rpm
And extruded into pellets. The pellets obtained above were immersed in liquid nitrogen, thrown into a Turbomill T250-4J (manufactured by Turbo Kogyo Co., Ltd.), and pulverized to collect only a 1,000 μm sieve.

Next, powder slush molding was performed using the above powder composition. As a method of powder slush molding, first, a 150 mm × 150 mm ×
A 3 mm plate was heated in an oven at 250 ° C., and about 800 g of the powder composition was placed thereon for 10 seconds and allowed to adhere.
The mixture was heated in an oven adjusted to ° C for 30 seconds, taken out of the oven, and cooled with water, and the epidermis having a thickness of about 0.8 mm was removed.

The following methods were used to evaluate the melt viscosity of the above pellets, the initial tensile properties of the skin, and the tensile properties after heat aging. Table 1 shows the obtained results.

The melt viscosity of the pellet was measured according to JIS K7210.
The melt flow rate was measured at 230 ° C. under a load of 2.16 kgf.

For the tensile properties, the skin obtained by slush molding was punched out with a JIS No. 3 dumbbell, and the tensile speed was 200 m.
The tensile strength and elongation at 100 m / min and 100% modulus were measured. In addition, it is judged that the lower the value of the 100% modulus, the more flexible.

The tensile properties after heat aging were as follows:
After heat aging for 200 hours in an oven controlled at 20 ° C., the skin left at room temperature of 23 ° C. for 24 hours was punched out with a JIS No. 3 dumbbell, and the tensile strength, elongation and 100% modulus were measured at a tensile speed of 200 mm / min. These results are also shown in Table 1.

[0050]

[Table 1]

As a result, in Examples 1 to 3 where 4% by weight or more of the amorphous polypropylene resin was added, the pellet M
FR is 230 ℃, 2.16k according to JIS K7210
With a load of gf of 20 g / 10 min or more, the composition had good melt fluidity and good sheet moldability, maintained almost the same physical properties as Comparative Example 1 as a conventional compound, and did not show any deterioration in physical properties after heat aging. The 100% modulus was 550 N / cm ² or less, which was lower than that of Comparative Example 1, and the flexibility was improved and the tactile sensation was improved. When the amount of the amorphous polypropylene resin is increased to 8% by weight as in Example 2,
The 0% modulus was 500 N / cm ² or less, which tended to significantly improve flexibility.

Comparative Example 1 is a composition containing no amorphous polypropylene resin, and has a melt flowability MFR = 106 g / 1.
Although the tensile strength and elongation were good at 0 minutes, the 100% modulus was as high as 616 N / cm ² , so the flexibility was poor and the feel was hard.

[0053]

As described above, in the invention described in each claim of the present application, at least the HS
BR and process oil, elastomer with excellent oil absorption,
A thermoplastic elastomer composition for powder molding is obtained by kneading under heating 4% by weight or more of an amorphous polypropylene resin for further flexibility, and the composition is MF.
R = 20 g / 10 min or more, excellent melt fluidity, the molded sheet is excellent in tensile strength and elongation, even after heat aging,
A material having excellent elongation, flexibility, and good tactile sensation can be obtained.

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Gakuhide Okazawa 4-1-1, Hamazoedori, Nagata-ku, Kobe Mitsuhoshi Belt Co., Ltd. F term (reference) 3D044 BA11 BB01 BC04 4F205 AA03 AA04 AA11 AA12 AA45 AA47 AB07 AC04 GA13 GB01 GC04 GF01 GF02 GF46 GN13 GN29 4J002 AC081 AE054 BB122 BB133 BB142 BB152 BP015 BP025 BP035 EP016 FD166 GN00

Claims (6)

[Claims] 1. A method comprising adding at least a hydrogenated styrene-butadiene random copolymer rubber, a crystalline polypropylene resin, an internal mold release agent, an elastomer having excellent oil absorbency, a process oil, and an amorphous polypropylene resin. Thermoplastic elastomer composition for slush molding. 2. The thermoplastic elastomer for slush molding according to claim 1, wherein the amorphous polypropylene resin is a homopolymer having a melt viscosity at 190 ° C. of 300 to 10,000 cp or a copolymer with an α-olefin. Composition. 3. The thermoplastic elastomer composition for slush molding according to claim 1, further comprising an organic peroxide. 4. The thermoplastic elastomer composition for slush molding according to claim 1, wherein the elastomer having excellent oil absorbing ability is an ethylene / octene copolymer having a long-chain branched structure. 5. A thermoplastic elastomer composition containing at least a hydrogenated styrene-butadiene random copolymer rubber, a crystalline polypropylene resin, an internal mold release agent, an elastomer having excellent oil absorption properties, a process oil, and an amorphous polypropylene resin. A slush-molded skin, characterized by being slush-molded using a slush-molded slush. 6. The slush-molded skin according to claim 5, wherein the amorphous polypropylene resin is a homopolymer having a melt viscosity at 190 ° C. of 300 to 10,000 cp or a copolymer with an α-olefin.