JPH062848B2 - Molding resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin composition for molding, and more specifically, a polyolefin-rubber modified polystyrene resin composition having excellent sheet moldability and vacuum / pressure air moldability. It is about.

2. Description of the Related Art Conventionally, for example, polyolefin resins such as polypropylene or propylene-ethylene copolymer are inexpensive and have relatively good processability, and therefore injection molding, film molding,
It was widely used as a resin material for sheet molding and blow molding.

On the other hand, the rubber-modified polystyrene-based resin has been used in various fields such as weak electricity, lighting, vehicles, furniture, and building materials because of its excellent moldability.

However, according to the above-mentioned polyolefin resin, the rigidity is small for producing a molded product having a predetermined shape, and the dimensional accuracy is poor due to shrinkage after molding, and further, in vacuum / pressure air molding, a sheet is used. Since the sagging phenomenon (drawdown) occurs, there is a drawback that a large-sized molded product cannot be manufactured. Further, the rubber-modified polystyrene resin has a drawback that impact strength is not sufficient, and also has a poor solvent resistance, so that there is a drawback that use is restricted due to occurrence of so-called crazing.

Thus, conventionally, various compositions have been proposed of a polyolefin resin and a rubber-modified polystyrene-based resin, while maintaining the advantages of both, and a blend composition of both polymers that compensates for the drawbacks. Since the structures are different and there is no compatibility, there is a problem that a resin composition having practical strength cannot be obtained by causing phase separation (exfoliation of surface layer) only by melt-mixing these polymers.

In order to solve the above problems, the present inventor firstly developed a quaternary element consisting of a propylene-ethylene block copolymer, a high-density polyethylene, a rubber-modified polystyrene-based polymer, and a styrene-butadiene block copolymer. A new molding resin composition composed of a copolymer has been proposed (see Japanese Patent Application No. 62-246544). However, the resin composition according to this prior proposal also has good deep drawing moldability in vacuum / pressure molding. It was not possible to obtain the thickness retention rate.

An object of the present invention is to solve the above problems all at once, to take advantage of the advantages of polyolefin-based resins and rubber-modified polystyrene-based resins, and to make up for the disadvantages, which are favorable in vacuum / pneumatic molding and extrusion sheet molding methods. It has sheet moldability and is not only able to obtain a sheet with excellent solvent resistance, impact resistance, heat resistance and rigidity, but the obtained sheet has good surface gloss and improved surface roughness. In addition to having a uniform skin, the sheet has outstanding deep drawability, thickness retention and dimensional stability in vacuum / pneumatic forming. An object of the present invention is to provide a molding resin composition which can be molded to obtain a molded product having excellent dimensional accuracy and appearance.

Means for Solving the Problems In order to achieve the above object, the present invention has a melt flow rate (MFR, 230 ° C.) (hereinafter abbreviated as MFR).
Is 10 g / 10 minutes or less and the ethylene content is 1 to
20% by weight of propylene-ethylene block copolymer (A) and melt flow index (MFI, 190
C) (hereinafter abbreviated as MFR) is 1 g / 10 minutes or less of high-density polyethylene (B) and a molecular weight of 200,000 to 400
000 rubber-modified polystyrene-based polymer (G), styrene-butadiene block copolymer (D) having a butadiene content of 30% by weight or less, methacrylic acid ester and acrylic acid ester as essential components, and their relative amounts. The former compounding ratio is 30 to 90% by weight, while the latter 7
0 to 10% by weight of an acrylic copolymer (E) is blended, and the blending ratio of these is propylene-ethylene block copolymer (A), high density polyethylene (B) and rubber modified polystyrene. Sum of 3 components of polymer (G) 10
3 to 30 parts by weight of styrene-butadiene block copolymer (D), and acrylic copolymer to 0 parts by weight
(E) is 1 to 15 parts by weight, and the sum of the two components (A) and (B) is 30 to 70% by weight in the total sum of the three components (A), (B) and (G). And (G) component is 70 to 30% by weight,
In the sum of the two components (A) and (B), the component (A) is 10-9.
The gist is a molding resin composition containing 0% by weight and 90 to 10% by weight of the component (B).

In the above, propylene-ethylene block copolymer
(A) has an MFR of 10 g / 10 minutes or less, 6 g / 10
Minutes or less are preferable. MFR of copolymer (A) is 10g / 1
If it exceeds 0 minutes, the amount of sagging in the preheating step during vacuum / pressure forming becomes large, wrinkles occur in the formed sheet, and a formed sheet having a uniform wall thickness cannot be obtained. Moreover, the molding temperature range is narrowed. In addition, there is no lower limit of the MFR of the block copolymer (A). This is because the propylene-ethylene block copolymer (A) does not cause surface peeling from other components even when it has no fluidity at the time of MFR measurement, so that it can be formed into a sheet.

The ethylene content of the block copolymer (A) is 1 to 2
It is 0% by weight, preferably 2 to 15% by weight.

Here, when the ethylene content is less than 1% by weight, the impact resistance of the resin composition is not sufficient, and when it exceeds 20% by weight, the impact resistance is good, but the rigidity and heat resistance of the molded product are not sufficient. It is not preferable.

The high-density polyethylene (B) is obtained by a so-called low-pressure method or medium-pressure method and has at least 0.93
Density of 0g / cc and MFI less than 1g / 10min
It is composed of an ethylene homopolymer having (190 ° C.) or a copolymer containing ethylene as a main component and another α-olefin such as butene.

Here, if the density of polyethylene (B) is less than 0.930 g / cc, the strength of the obtained molded article will be reduced, which is not preferable.

When the MFI of polyethylene (B) exceeds 1 g / 10 min, the above propylene-ethylene block copolymer is used.
Since the same problem as in the case of (A) occurs, it is not preferable.
The lower limit of MFI of polyethylene (B) is not particularly limited, but from the viewpoint of heat resistance, it is preferable to use high density polyethylene having MFI of 0.5 g / 10 min or less.

The rubber-modified polystyrene-based copolymer (G) is generally called impact-resistant polystyrene, which is a copolymer obtained by polymerizing a styrene monomer in the presence of a rubber-like polymer. It can be produced by a bulk polymerization method or a bulk suspension polymerization method.

Such a rubber-modified polystyrene-based copolymer (G) has a molecular weight of 200,000 to 400,000 and a rubber component content of about 5 to 9% by weight. Also, usually melt flow index (MFI, 200 ° C.) 0.1 to 40 g / 10 minutes,
It preferably has 1 to 10 g / 10 minutes.

During the production of the rubber-modified polystyrene-based copolymer (G), in the polymerization of the styrene monomer in the presence of the rubber-like polymer, an aromatic monovinyl monomer other than styrene may be used in combination if necessary. good. Such aromatic monovinyl monomers include o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene,
Nuclear alkyl-substituted styrenes such as ethylstyrene and p-ter-butylstyrene are used, and α-alkyl-substituted styrenes such as α-methylstyrene and α-methyl-p-methylstyrene are used.

The content of these aromatic monovinyl monomers is 50
% Or less is preferable.

Examples of the rubber-like polymer include polybutadiene and styrene-butadiene copolymer. As the polybutadiene, high cis polybutadiene having a high cis content or o-cis polybutadiene having a low cis content can be used.

The rubber-modified polystyrene-based copolymer (G) has a molecular weight of 20.
It has 0000-400000. here,
The rubber-modified polystyrene-based copolymer (G) has a molecular weight of 200.
If it is less than 000, the heat resistance and solvent resistance of the molded product are not sufficient, and the dimensional stability is also poor. When the molecular weight of the rubber-modified polystyrene-based copolymer (G) exceeds 400000, the compatibility with the polyolefin-based resin is markedly deteriorated, and the surface layer peeling easily occurs.

Also, the rubber component content and melt flow index (MFI, 200 ° C) of the rubber-modified polystyrene-based copolymer (G)
Is within the normal range as described above.

The particle size of the rubber-modified polystyrene-based copolymer (G) is also not particularly limited, and those having an average particle size of 0.30 to 5 μm are usually used.

Further, the styrene-butadiene block copolymer
(D) includes those shown in (a) to (c) below.

(A) A linear block copolymer represented by the general formula (AB) n or (AB) nA (n is a positive integer).

(B) General formula ABA, or Star-shaped block copolymer represented by.

(C) A so-called styrene-butadiene taper block copolymer containing an AB random copolymer portion in the transition portion between the block A and the block B.

Here, as the substance constituting the block A, vinyl aromatic compounds such as styrene, vinyltoluene, tertiary butylstyrene, α-styrene and chlorostyrene are used.

Further, as a substance forming the block B, a conjugated diene such as butadiene and isoprene is used.

In the styrene-butadiene block copolymer (D),
When the butadiene component is low, as a thermoplastic resin,
It is generally known that when a large amount of conjugated gen component is present, it functions as a thermoplastic rubber, but in the present invention, a so-called thermoplastic resin type styrene-containing butadiene having a butadiene content of 30% by weight or less is used. A butadiene block copolymer is used.

Here, when the content of butadiene exceeds 30% by weight,
The block copolymer has a high rubber content and exhibits rubber-like elasticity, so that it is not preferable because it is inferior in rigidity and heat resistance when formed into a large-sized sheet.

Of the styrene-butadiene block copolymers (a) to (c) above, it is preferable to use the tapered block copolymer (c).

This is a block copolymer having a portion in which the composition ratio of each monomer unit of styrene and butadiene continuously changes along the polymer chain (JP-A-48-4854).
(See No. 6).

Here, the rubber-modified polystyrene-based copolymer (G)
The difference between the styrene-butadiene block copolymer (D) and the structural difference is that the former is produced by a bulk polymerization method or a bulk suspension polymerization method, while the latter is an anion. It is clearly different in that it is produced by living polymerization.

The acrylic copolymer (E) has methacrylic acid ester and acrylic acid ester as essential components,
Various forms of copolymers such as ordinary copolymers and multistage copolymers are effective. The relative proportion of both is 30-9
The latter is 70 to 10% by weight, while the latter is 0% by weight.

The methacrylic acid ester (i) and the acrylic acid ester (ii) are represented by the following general formula.

CH ₂ ═CH COOR In the formula, R means the same or different alkyl groups such as ethyl group, bull group, octyl group and stearyl group.

If the amount of methacrylic acid ester is less than 30% by weight and the amount of acrylic acid ester is more than 70% by weight, the thermoformability and surface gloss are not significantly affected, and the heat resistance and rigidity of the molded product are deteriorated. Therefore, it is not preferable.
On the other hand, when the methacrylic acid ester exceeds 90% by weight and the acrylic acid ester is less than 10% by weight, the impact resistance and elongation of the molded product decrease, and the thickness retention of the molded product during heat molding becomes insufficient. Therefore, it is not preferable.

The molecular weight is another factor that controls the thermoformability of the acrylic copolymer (E). Here, the molecular weight of the acrylic copolymer (E) is equivalent to a reduced viscosity measured at 25 ° C. of 0.2 to 2.0 dl / g for a solution of 0.1 g of the polymer dissolved in 1 dl of chloroform. It must be within the range. If the reduced viscosity exceeds 2.0 dl / g, the melt viscosity will become extremely high, so other components
The compatibility with (A), (B), (G), and (D) is poor, and in particular, the surface gloss of the molded product decreases, which is not preferable.

The acrylic copolymer (E) contains methacrylic acid ester and acrylic acid ester as essential components, but if necessary, it is possible to contain one kind or two or more kinds of vinyl compounds copolymerizable with them. Examples of vinyl compounds include vinyl cyanide and vinyl esters. Further, it is also possible to use a polyfunctional monomer such as divinylbenzene, diallyl phthalate or triallyl cyanurate, but in these cases, the amount of the vinyl compound and the polyfunctional monomer used is the acrylic copolymer.
It is preferable that the total amount of (E) is 100% by weight, and the total amount is 5% by weight or less.

The compounding ratio of each component of the molding resin composition according to the present invention is as follows.

That is, first, a propylene-ethylene block copolymer
(A), high-density polyethylene (B), and rubber-modified polystyrene-based copolymer (G), based on 100 parts by weight of the total of the three components, styrene-butadiene block copolymer (D) is 3 to.
30 parts by weight, preferably 8 to 15 parts by weight, and the acrylic copolymer (E) is 1 to 15 parts by weight, preferably 3 parts by weight.
~ 7 parts by weight.

Here, in general, a propylene-ethylene block copolymer
(A) and high-density polyethylene (B), that is, a polyolefin-based polymer, and a rubber-modified polyethylene-based copolymer (G) have almost no compatibility, while the styrene-butadiene block copolymer (D) is a rubber. High compatibility with modified polystyrene polymer (G), but polyolefin polymer
The compatibility with (A) and (B) is weak. Acrylic copolymer (E) is
It has a relatively good compatibility with the polyolefin polymers (A) and (B) and the rubber-modified polystyrene polymer (G), but it is not sufficient to mix them evenly. Therefore, a styrene-butadiene block copolymer is added to the three-component system of the polyolefin polymer (A) (B) and the rubber-modified polystyrene polymer (G).
When (D) and the acrylic copolymer (E) are added, the compatibility of (G) with (A) (B) is improved, and (A) (B) (G) (D) (E) It has been found that the ingredients mix uniformly.

In the above, styrene-butadiene block copolymer
If the amount of (D) is less than 3 parts by weight, the polyolefin-based polymer (A)
The dispersibility of (B) is not sufficient, and a polyolefin polymer
Poor dispersion of (A) and (B) occurs, resulting in delamination of the molded article of the resin composition, which is not preferable. When the styrene-butadiene block copolymer (D) exceeds 30 parts by weight,
Although the dispersibility of the polyolefin polymers (A) and (B) is good, the chemical resistance, which is a characteristic of the propylene-ethylene block copolymer (A), is significantly impaired, and the production cost is high.

When the amount of the acrylic copolymer (E) is less than 1 part by weight, a preferable balance between elongation and tensile strength at the time of heat cannot be obtained during vacuum / pneumatic molding, and a large-sized molded product having a uniform wall thickness cannot be obtained. . If the acrylic copolymer (E) exceeds 15 parts by weight,
The compatibility with other components (A) (B) (G) is remarkably low, no improvement in dispersibility is observed even if the component (D) is added, and layered peeling occurs and impact resistance and heat resistance are also reduced. Is not preferred.

The acrylic polymer (E) has a function of uniformly mixing the components (A), (B), (G) and (D), and the acrylic copolymer (E) is added to these components. As a result, the flow during extrusion molding becomes smooth, the surface gloss is good, and a molded sheet having a uniform surface and an excellent surface condition can be obtained. Such an acrylic copolymer (E) has 1 to 1
It is preferably used in an amount of 5% by weight, particularly 3 to 7 parts by weight.

Next, propylene-ethylene block copolymer (A),
When the total amount of the high-density polyethylene (B) and the rubber-modified polystyrene-based polymer (G) is 100% by weight, the sum of the two components (A) and (B) is 30 to 70% by weight, preferably 40 to 60% by weight, and (G) component is 70 to 30% by weight, preferably 60 to 40% by weight.

If the rubber-modified polystyrene-based polymer (G) is less than 30% by weight, a preferable molding temperature range and dimensional stability cannot be obtained during vacuum / pneumatic molding, and a molded product having a sufficient thickness retention cannot be obtained. . Moreover, there is almost no homogenous effect to prevent sagging of the sheet. Further, the extrusion dischargeability becomes low, and the warp or shrinkage of the sheet occurs due to the crystallinity peculiar to olefin, and the extrudability is deteriorated, which is not preferable. Furthermore, the surface of the sheet is roughened and the surface gloss is reduced, which is not preferable in terms of appearance. On the other hand, when the rubber-modified polystyrene-based copolymer (G) exceeds 70% by weight, the resin composition is inferior in impact resistance and chemical resistance, and elongation is deteriorated, resulting in deterioration of physical properties.

In the sum of the two components of the propylene-ethylene block copolymer (A) and the high-density polyethylene (B), (A) is 10 to 90% by weight, preferably 30 to 80% by weight, and (B) is 90 to 90% by weight.
It is 10% by weight, preferably 80 to 30% by weight.

Here, the propylene-ethylene block copolymer (A) is less than 10% by weight, and the high-density polyethylene (B) is 90% by weight.
When it exceeds the weight%, the heat resistance decreases. Also (A) is 90
If more than 10% by weight and (B) is less than 10% by weight,
Impact resistance decreases.

If the blending ratio of the propylene-ethylene block copolymer (A) and the high-density polyethylene (B) is within the above range, the drawability during vacuum / pressure forming will increase as the amount of the component (B) increases. Although it is improved, this is not sufficient, and the rubber-modified polystyrene polymer (G) and the acrylic copolymer (E) are added within the above range in order to further increase the drawability.

To produce the molding resin composition according to the present invention,
The five constituents (A) to (E) may be blended in a predetermined ratio and dry blended using a commonly used mixer such as a Hensiel mixer or a tumbler, or a Banbury. The mixture may be kneaded with a mixer, a kneader, a screw extruder or the like to once form a pelletized compound.

In this case, a stabilizer that is generally used in the field of polyolefin-based resins and rubber-modified polystyrene-based resins against oxygen, heat and light, or a deterioration inhibitor,
For example, a required amount of a filler such as talc, silica, calcium carbonate, a lubricant, a flame retardant and a coloring agent may be further added. Among the fillers, it is particularly preferable to use talc.

The resin composition according to the present invention is usually molded into a sheet by an extrusion molding method. In this case, the sheet can be directly formed into a sheet by a dry blending method or the like, but is usually formed into a sheet by an extrusion molding method from a pellet compound. The obtained sheet is further formed into a product having a desired shape by a vacuum / pressure forming method, a press forming method, or the like. These molding methods are widely known in the field of synthetic resins.

Incidentally, the pelletized compound of the resin composition according to the present invention can be directly introduced into a predetermined mold and heated to obtain a molded product without molding the compound into a sheet.

The molding resin composition according to the present invention is an electric / electronic device,
It is used for various purposes such as automobiles, various machine components, interior / exterior parts, and housings.

Examples Next, examples of the present invention will be described.

The following components were used to obtain the molding resin composition according to the present invention.

Component (A) A propylene-ethylene block copolymer having an MFR (230 ° C.) of 0.5 g / 10 minutes and an ethylene content of 10% by weight.

(B) Component High density polyethylene having MFI (190 ° C.) of 0.25 g / 10 minutes.

(G) component molecular weight 270000, rubber component content 8.2% by weight, M
A rubber-modified polystyrene homopolymer having an FI (200 ° C.) of 2.2 g / 10 min.

Component (D) A styrene-butadiene block copolymer having a butadiene content of 25% by weight.

(E) Component Acrylic copolymer containing methacrylic acid ester and acrylic acid ester as essential components (trade name: METABLEN P
551, manufactured by Mitsubishi Rayon Co., Ltd.).

These components are blended in various proportions as shown in the table below to prepare pellet-shaped compounds of the resin compositions of Sample Nos. 1 to 18, and then these are extruded sheet molding method to have a length of 1000 mm and a width of 500 mm. And formed into a sheet having a thickness of 4 mm. At this time, each sample was evaluated for sheet formability, sheet appearance, solvent resistance, heat resistance, impact resistance and rigidity.

Next, the sample sheet is cut into a size of 500 mm square, and the expansion rate of each sheet piece is 3 times (450 mm length × 400 mm width × 212 mm height) and 5 times (450 mm length × 400 mm width) by the vacuum / pressure forming method. Deep-drawing was performed in the form of a square cylinder with a bottom and a height of 424 mm.

The vacuum / pneumatic molding method was based on the plug assist method.

At this time, the deep drawability of each sample piece and the dimensional stability of the molded product, especially regarding the external shape, were measured in the molding with a development rate of 5 times, and the thickness retention rate of each sample piece was measured with a development rate of 3 times. Measurements were made during molding and these results are summarized in the table below.

The resin compositions of Sample Nos. 3, 4, 8, 9, 13, 14, 15, and 18 are comparative examples, and the value of the component of * is out of the range of the present invention.

Method of measuring physical properties (i) Sheet moldability was measured by an extrusion molding method. That is, with respect to the extruded sheet, those having no layer peeling, so-called warpage and sink marks and having a good discharge amount were marked with ◯, and those not having such discharge amount were marked with x.

(ii) Regarding the appearance of the sheet, the state of surface gloss and rough surface of each sample sheet was observed. Good surface gloss,
And, those with clean skin were marked with ○, and those with poor skin were marked with ×.

(iii) Regarding the solvent resistance, each material sheet was immersed in acetone (20 ° C. × 3 days) to evaluate the appearance, particularly the occurrence of cracks and the swelling state.

(iv) Heat resistance is load 1 based on ASTM D648
It was measured at 8.6 kg / cm ² .

(v) Impact resistance was measured by the ASTM D256 Izod method (with V notch) method.

(vi) Stiffness was based on ASTM D790 method for measuring flexural modulus.

(vii) Deep drawability is 5 by the vacuum / pneumatic forming method.
When deep-drawing was performed twice, it was evaluated whether or not the sagging was small at the time of heating and there was no breakage at the time of forming.

(viii) The thickness retention was expressed as the ratio of the thickness of the bottom of the molded product to the original thickness of each sheet piece when the expansion ratio was 3 times. And, a thickness retention rate of 45 to 80% is ◯,
Those less than 45% were marked with x.

(ix) Regarding dimensional stability, regarding the appearance of vacuum / compressed air-molded products with a development rate of 5 times, observe that there is no waviness or warpage. did.

As is apparent from the above table, the sample No. according to the present invention.
The resin compositions of 1, 2, 5, 6, 7, 10, 11, 12, 16, 17 have good sheet moldability and sheet appearance, and have solvent resistance, impact resistance, heat resistance and A sheet with excellent rigidity can be obtained, and the obtained sheet has a good surface gloss and a clean skin, and has excellent deep drawability, thickness retention and dimensional stability, and a vacuum A molded product having excellent dimensional accuracy and appearance can be obtained by the pressure molding, and the obtained molded products are sample Nos. 3, 4, 8, 9, 13, 1 of other comparative examples.
It had much better physical properties than the resin compositions of 4, 15, and 18.

EFFECTS OF THE INVENTION As described above, the molding resin composition according to the present invention has a melt flow rate (MFR, 230 ° C.) of 10 g / 10.
Propylene-ethylene block copolymer (A) having an ethylene content of 1 to 20% by weight and a melt flow index (MFI, 190 ° C.) of 1 g / 1
High-density polyethylene (B) of 0 minutes or less and molecular weight 2000
00-400000 rubber-modified polystyrene-based polymer
(G), a styrene-butadiene block copolymer (D) having a butadiene content of 30% by weight or less, a methacrylic acid ester and an acrylic acid ester as essential components, and the relative proportion of both is 30 to 90% by weight. %, The latter 70 to 10% by weight of the acrylic copolymer (E)
And are blended, and the blending ratio of these is propylene-ethylene block copolymer (A), high-density polyethylene
3 to 30 parts by weight of the styrene-butadiene block copolymer (D), and an acrylic copolymer ((B) and the rubber-modified polystyrene-based copolymer (G) with respect to 100 parts by weight in total. E) is 1 to 15 parts by weight, and the above (A) and (B)
And in the total of the three components of (G), the sum of the two components of (A) and (B) is 30 to 70% by weight, and the amount of the (G) component is 70 to 30% by weight.
In the sum of the above two components (A) and (B), the component (A) is 10 to 90% by weight and the component (B) is 90 to 10% by weight. According to the resin composition for use, the advantages of the polyolefin-based resin and the rubber-modified polystyrene-based resin can be utilized, and the disadvantages can be compensated for, and has good sheet formability in vacuum / pressure forming and extrusion sheet forming methods. In addition, it is possible to obtain a sheet excellent in solvent resistance, impact resistance, heat resistance and rigidity, and the obtained sheet has a good surface gloss and can improve the surface roughness to obtain a uniform skin. In addition, the sheet has remarkably excellent deep drawing formability, thickness retention and dimensional stability in vacuum / pneumatic forming.By forming this sheet into a predetermined shape, dimensional accuracy is improved. And excellent appearance An effect that it is possible to obtain a molded article.

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Claims (1)

[Claims] 1. Melt flow rate (MFR, 230 ° C.)
Is 10 g / 10 minutes or less and the ethylene content is 1 to
20% by weight of propylene-ethylene block copolymer (A) and melt flow index (MFI, 190
High-density polyethylene (B) with a temperature of 1g / 10 minutes or less,
A rubber-modified polystyrene-based polymer (G) having a molecular weight of 200,000 to 400,000, a styrene-butadiene block copolymer (D) having a butadiene content of 30% by weight or less, a methacrylic acid ester and an acrylic acid ester as essential components, and The former is 30 to 90% by weight, while the latter is 70 to 10% by weight, and the latter is 70 to 10% by weight, and the acrylic copolymer (E) is blended. With respect to 100 parts by weight of the total of the three components of the ethylene block copolymer (A), the high-density polyethylene (B) and the rubber-modified polystyrene-based polymer (G), the styrene-butadiene block copolymer (D) is 3 to. 30 parts by weight and 1 to 15 parts by weight of the acrylic copolymer (E), and (A) out of the sum of the above three components (A), (B) and (G)
The sum of the two components of (B) is 30 to 70% by weight, and the content of the (G) component is 70 to 30% by weight. In the total sum of the above two components of (A) and (B), the (A) component is A molding resin composition containing 10 to 90% by weight and (B) component of 90 to 10% by weight.