JPH02120346A - Molding resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition having excellent vacuum and pressure formability and capable of giving a molding of excellent dimensional accuracy and appearance by mixing a plurality of specified polyolefin polymers with a rubber-modified PS polymer in a specified mixing ratio. CONSTITUTION:A propylene/ethylene block copolymer (A) of an MFR <=10g/10min at 230 deg.C and an ethylene content of 1-20wt.% is mixed with a high-density PE (B) of an MFI <=1g/10min at 190 deg.C, a rubber-modified PE polymer (C) of an MW of 200,000-400,000, a styrene/butadiene block copolymer (D) of a butadiene content <=30wt.% and an acrylic copolymer (E) containing 30-90wt.% methacrylic ester and 70-10wt.% acylic ester. The title composition is produced by mixing the above components in such a ratio that 3-30 pts.wt. component D and 1-15 pts.wt. component E are present per 100 pts.wt. in total of the three components A, B and C; the sum of components A and B and the amount of component C are 30-70wt.% and 70-30wt.%, respectively, based on the total of the three components A, B and C; and the amount of component A and the amount of component B are 10-90wt.% and 90-10wt.%, respectively, based on the total of components A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a molding resin composition, more specifically a polyolefin-rubber modified polystyrene resin composition having excellent sheet formability and vacuum/pressure formability. It is related to.

Conventional technology Conventionally, polyolefin resins such as polypropylene or propylene-ethylene copolymers have been used for injection molding, film molding,
It was widely used as a resin material for sheet molding, blow molding, etc.

On the other hand, rubber-modified polystyrene resins have excellent moldability and have been used in various fields such as light electrical appliances, lighting, vehicles, furniture, and building materials.

Problems to be Solved by the Invention However, according to the polyolefin resin, the rigidity is too low to make a molded product with a predetermined shape, the dimensional accuracy is poor due to shrinkage after molding, and furthermore, during vacuum/pressure forming, the sheet cannot be easily formed. This has the disadvantage that it is not possible to manufacture large molded products because of the sagging phenomenon (drawdown). Furthermore, the above-mentioned rubber-modified polystyrene resin has the disadvantage that it does not have sufficient impact strength, and is also poor in solvent resistance, so it has the disadvantage that it is limited in its use due to the occurrence of so-called crazing.

Therefore, various blend compositions of polyolefin resin and rubber-modified polystyrene-based resin have been proposed that compensate for the drawbacks while maintaining the advantages of both. Due to their different structures and lack of compatibility, simply melt-mixing these polymers will result in phase separation (surface layer peeling).
There was a problem that a resin composition with practical strength could not be obtained.

In order to solve the above problems, the present inventors have previously developed a quaternary polymer consisting of a propylene-ethylene block copolymer, a high-density polyethylene, a rubber-modified polystyrene polymer, and a styrene-butadiene block copolymer. We proposed a new molding resin composition composed of a copolymer (see Japanese Patent Application No. 62-246544), but the resin composition proposed earlier also showed good deep drawability and good deep drawability in vacuum and pressure forming. It was not possible to obtain a sufficient thickness retention rate.

The purpose of this invention is to solve the above problems all at once, to take advantage of the advantages of polyolefin resins and rubber-modified polystyrene resins, and to compensate for their disadvantages. Not only is it possible to obtain a sheet that has sheet formability and is excellent in solvent resistance, impact resistance, heat resistance, and rigidity, but also the obtained sheet has a good surface gloss and has improved surface roughness. In addition to having a uniform skin, the sheet has outstanding deep drawability, thickness retention, and dimensional stability in vacuum/pressure forming, and the sheet can be deep drawn into the specified shape. The object of the present invention is to provide a molding resin composition that can be molded to obtain molded products with excellent dimensional accuracy and external shape.

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) of less than Log/10 minutes and an ethylene content. 1 to 20% by weight of propylene-ethylene block copolymer (A) and melt flow index (MFI,
190°C) (hereinafter abbreviated as MFI) is 1 g/10 minutes or less high-density polyethylene (B) and a molecular weight of 2oooooo
~400,000 rubber-modified polystyrene polymer (G)
, a styrene-butadiene block copolymer (D) having a butadiene content of 30% by weight or less, a methacrylic ester and an acrylic ester as essential components, and the relative blending ratio of the former is 30 to 90% by weight. %, while the latter is 70-10% by weight of the acrylic copolymer (
E), and the blending ratio of these is a propylene-ethylene block copolymer (A), a high-density polyethylene (B), and a rubber-modified polystyrene polymer (G).
), the styrene-butadiene block copolymer CD) is 3 to 30 parts by weight, and the acrylic copolymer (E) is 1 to 15 parts by weight. ), (B) and CG), the sum of the two components (A) and (B) is 30 to 70% by weight, and the component (G) is 70 to 30% by weight, and the above ( A)
In the sum of the two components of and (B), the component (^) is 10~
The gist is a molding resin composition containing 90% by weight and 90 to 10% by weight of component (B).

In the above 1, the MFR of the propylene-ethylene block copolymer (A) is 10 g/10 minutes or less, and 6 g/10 min.
10 minutes or less is preferable. MFR of copolymer (A) is Lo
If it exceeds g/10 minutes, the amount of sag will increase in the preheating step during vacuum/pressure forming, wrinkles will occur in the formed sheet, and a formed sheet with uniform thickness will not be obtained. Moreover, the molding temperature range becomes narrower. Note that there is no lower limit to the MFR of the block copolymer (A). This is because the propylene-ethylene block copolymer (A) is M F Ril
This is because even if there is no fluidity at a certain time, the surface layer will not peel off from other components, so any material that can be formed into a sheet is sufficient.

Moreover, the ethylene content of the block copolymer (A) is 1 to
20% by weight, preferably 2-15% by weight.

Here, if the ethylene content is less than 1% by weight, the impact resistance of the resin composition is insufficient, and if it exceeds 20% by weight, the impact resistance is good, but the rigidity and heat resistance of the molded product are insufficient. So I don't like it.

The above-mentioned high-density polyethylene (B) is obtained by a so-called low pressure method or medium pressure method, and is at least 0.9
Density of 30g/cc and M less than 1g/10min
It consists of an ethylene homopolymer having FI (190°C) or a copolymer containing ethylene as a main component and other α-olefins such as butene.

Here, the density of polyethylene (B) is 0.930 g/c
If it is less than c, the strength of the molded product obtained will decrease, which is not preferable.

Furthermore, if the MFI of polyethylene (B) exceeds 1 g/10 minutes, the same problems as those of the propylene-ethylene block copolymer (A) described above will occur, which is not preferable. Although there is no particular restriction on the lower limit of MFI of polyethylene (B), from the viewpoint of heat resistance, it is preferable to use high-density polyethylene with MFIo of 5 g/10 minutes or less.

The above-mentioned rubber-modified polystyrene copolymer (G) is generally referred to as impact-resistant polystyrene, and is a copolymer obtained by polymerizing a styrene monomer with a rubber-like polymer. It can be produced by a bulk polymerization method or a bulk suspension polymerization method.

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

In the production of rubber modified polystyrene copolymer (G),
In polymerizing the styrene monomer to form a rubbery polymer, an aromatic monovinyl monomer other than styrene may be used in combination as necessary. Such aromatic monovinyl monomers include 0-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.

In addition, the content of these aromatic monovinyl monomers is 50
% or less is preferable.

Examples of the rubbery polymer include polybutadiene, styrene-butadiene copolymer, etc., and as the polybutadiene, high-cis polybutadiene with a high cis content or O-cis polybutadiene with a low cis content can be used, respectively. .

The above rubber-modified polystyrene copolymer (G) has a molecular weight of 2
00000 to 400000. Here, the molecular weight of the rubber-modified polystyrene copolymer (G) is 2.
If it is less than 00,000, the molded product will not have sufficient heat resistance and solvent resistance, and will also lack dimensional stability. The molecular weight of the rubber modified polystyrene copolymer (G) is 400,000
If it exceeds 100%, the compatibility with the polyolefin resin will be markedly poor, and surface layer peeling will easily occur.

Furthermore, the rubber component content and melt flow index (MFl, 200°C) of the rubber-modified polystyrene copolymer (G)
) should be within the normal range as shown above.

There is also no particular restriction on the particle size of the rubber-modified polystyrene copolymer (G), and those with an average particle size of 0.30 to 5 μm are usually used.

Furthermore, the above styrene-butadiene block copolymer (
1)) include those shown in (a) to (lX) below.

(A) General formula (A-B)n.

or (A-B)n-A A linear block copolymer represented by (n is a positive integer).

(b) A star-shaped block copolymer represented by the general formula A-B-8 or A-B-^.

(c) A so-called styrene-butadiene tapered block copolymer containing an AB silane copolymer portion in the transition region between block A and 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.

Moreover, as the substance constituting block B, conjugated dienes such as butadiene and isoprene are used.

It is generally known that the styrene-butadiene block copolymer (D) functions as a thermoplastic resin when the butadiene component is low, and as a thermoplastic rubber when the conjugated diene component is high. In this invention, a so-called thermoplastic resin type styrene-butadiene block copolymer having a butadiene content of 30 weight or less is used.

Here, if the content of butadiene exceeds 30% by weight,
A block copolymer has a high rubber content and exhibits rubber-like elasticity, so when it is molded into a large-sized molding sheet, the rigidity and heat resistance are poor, so it is not preferable.

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

This is a block copolymer in which the proportion of each monomer unit of styrene and butadiene changes continuously along a polymer chain (Japanese Patent Laid-Open No. 48-4854
(See No. 6).

Here, the rubber-modified polystyrene copolymer (G
) and the styrene-butadiene block copolymer (D), as well as their structural differences, are that the former is produced by a bulk polymerization method or a bulk suspension polymerization method, whereas the latter is produced by a bulk polymerization method or a bulk suspension polymerization method. It is clearly different in that it is produced by anionic living polymerization.

The above-mentioned acrylic copolymer OE> contains a methacrylic ester and an acrylic ester as essential components, and various forms of copolymers such as ordinary copolymers and multistage copolymers are effective.

The relative blending ratio of the two is 30 to 90% by weight for the former, while 70 to 10% by weight for the latter.

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

H) CH2-CCOOR1(ii) CH2=CI(
In the C0OR formula, R means the same or different alkyl groups such as ethyl group, pull group, octyl group and stearyl group.

Here, if the total amount of methacrylic ester is less than 30 weight and the total amount of acrylic ester exceeds 70 weight, no remarkable effect will be obtained on thermoformability and surface gloss, and the heat resistance and rigidity of the molded product will decrease. Therefore, it is not desirable.

Furthermore, if the total amount of methacrylic acid ester exceeds 90% by weight and the total amount of acrylic ester is less than 10% by weight, the impact strength and elongation of the molded product will decrease, and the thickness retention rate of the molded product during heat molding will be insufficient. Therefore, it is not desirable.

Another factor governing the thermoformability of the acrylic copolymer (E) is the molecular weight. here,
The molecular weight of the acrylic copolymer (E) is 2 for a solution of 0.1 g of the polymer dissolved in 1 d/ml of chloroform.
The reduced viscosity measured at 5°C is 0.2 to 2. Od//g
It is necessary that the range corresponds to . Reduced viscosity is 2
If it exceeds ゜Od//g, the melt viscosity will become extremely high, resulting in poor compatibility with other components (＾”) (B) (G) (D), and the surface gloss of the molded product will deteriorate. This is not preferable because it lowers the temperature.

The acrylic copolymer (E) contains a methacrylic ester and an acrylic ester as essential components, but if necessary, it can contain -L or two or more vinyl compounds copolymerizable with these. Examples of the vinyl compound include vinyl cyanide and vinyl ester. Furthermore, it is also possible to use a polyfunctional heptamer such as divinylbenzene, diallyl phthalate, or triallyl cyanurate; Preferably, it is contained in a proportion of 5% by weight or less, assuming that the total of E) is 100% by weight.

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

That is, first, styrene-butadiene block copolymer ( [)
) is 3 to 30 parts by weight, or 8 to 15 parts by weight, and the acrylic copolymer (E) is 1 to 15 parts by weight, preferably 3 to 7 parts by weight.

Here, in general, a propylene-ethylene block copolymer (A) and a high-density polyethylene (B), that is, a polyolefin polymer, and a rubber-modified polyethylene polymer (
G) is hardly compatible with styrene-butadiene block copolymer (G), while styrene-butadiene block copolymer (G) is highly compatible with rubber-modified polystyrene polymer (G); A) Compatibility with (B) is weak. Acrylic copolymer (E) is polyolefin polymer (A) (
Although it has relatively good compatibility with B) and the rubber-modified polystyrene polymer (G), it is not sufficient for uniform mixing. Therefore, styrene-butadiene block copolymer (D>) and acrylic copolymer (E) are added to the three-component system of polyolefin polymer (^) (B) and rubber-modified polystyrene polymer (6). , the compatibility of (G) with (A) (B) is improved, and (A) (B) (G)
CD) It was found that the five components of (E) were uniformly mixed.

If the mistyrene-butadiene block copolymer (D) is less than 3 parts by weight in the above S1, the dispersibility of the polyolefin polymer (A) (B) will not be sufficient, and the polyolefin polymer (A) <8) is not preferable because poor dispersion occurs and delamination occurs in molded articles of the resin composition.

In addition, styrene-butadiene block copolymer CD)
If it exceeds 0 parts and 2 parts, the polyolefin polymer (A)
Although the dispersibility of (B) is good, the chemical resistance, which is a characteristic of the propylene-ethylene block copolymer (A), is significantly impaired and the manufacturing cost is high.

Furthermore, if the acrylic copolymer zone (E) is less than 1 part by weight, a desirable balance between elongation and tensile strength when heated cannot be obtained during vacuum/pressure forming, and large molded products with uniform wall thickness cannot be obtained. . When the acrylic copolymer (E) exceeds 15 parts by weight, the compatibility with other components (A), (B), and (G) becomes significantly low, and even when component (D) is added, dispersibility is improved. This is not preferable because it causes delamination and decreases impact resistance and heat resistance.

In addition, the acrylic polymer (E) is (A) (I3>
(G) It has the effect of uniformly mixing components (D), and by adding the acrylic copolymer (E) to these components, the flow during extrusion molding becomes smooth, the surface gloss is good, A molded sheet with a uniform skin and excellent surface condition can be obtained. Such acrylic copolymer (E) is preferably used in an amount of 1 to 15 parts by weight, particularly 3 to 7 parts by weight.

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

If the rubber-modified polystyrene polymer (G) is less than 30% by weight, the desired molding temperature range and dimensional stability cannot be obtained during vacuum/pressure molding, and a molded product with sufficient thickness retention cannot be obtained. . Moreover, there is hardly any homogenization effect for preventing sheet sag. Further, the extrusion properties are also lowered, and the sheet warps and shrinks due to the crystallinity peculiar to olefins, which is undesirable because the extrusion processability is poor. Furthermore, the surface of the sheet becomes rough and the surface gloss decreases, which is unfavorable in terms of appearance. If the rubber-modified polystyrene polymer (G) exceeds 70% by weight, the physical properties of the resin composition will deteriorate, such as poor impact resistance and chemical resistance, and poor elongation.

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

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

If the blending ratio of propylene-ethylene block copolymer (^) and high-density polyethylene (B) is within the above range,
As the amount of component (B) increases, the drawability during vacuum/pressure forming improves, but this alone is not sufficient, and in order to further increase the drawability, rubber-modified polystyrene polymer (G) and acrylic The copolymer (E) is added within the above range.

In order to produce the molding resin composition according to the present invention, the five components (A) to (E) described above are blended in a predetermined ratio, and the resin composition is prepared using a commonly used Henschel mixer or tumbler. The mixture may be triblended using a mixer, or may be kneaded using a Banbury mixer, kneader, screw extruder, etc. to form a pellet-like compound.

In this case, stabilizers against oxygen, heat and light, or deterioration inhibitors commonly used in the field of polyolefin resins and rubber-modified polystyrene resins, fillers such as talc, silica, charcoal, lubricants, flame retardants, etc. Additionally, a required amount of a coloring agent or the like may be 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 extrusion molding. In this case, although it is possible to directly form the sheet into a sheet by a triblend method or the like, it is usually formed into a sheet from a pellet-like compound by an extrusion molding method.

The obtained sheet is further molded into a product having a desired shape by a vacuum/pressure forming method, a press molding method, or the like. These molding methods are widely known in the field of synthetic resins.

Incidentally, it is of course possible to obtain a molded article by directly introducing the pellet-shaped compound of the resin composition according to the present invention into a predetermined mold and heating it without molding it into a sheet.

The molding resin composition according to the present invention can be used for electrical/electronic equipment,
It is used for various purposes such as automobiles, various mechanical components, interior and exterior parts, and housings.

Example Next, this invention will be explained in detail.

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

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

(B) High-density polyethylene whose component MFI (190°C) is 0.25 g/10 minutes.

(G) component molecular weight 270000, rubber component content ff18.2% by weight
, a rubber-modified polystyrene homopolymer with an MFI (200° C.) of 2.2 g/10 min.

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

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

These components were blended in various proportions as shown in the table below to make pellet-like compounds of the resin compositions of samples No. 1 to 18, and then these were molded into pellets of length 100011 width 500 mm and width 500 mm by extrusion sheet molding method. thickness 4
■It was molded into a sheet. At this time, each sample was evaluated for sheet formability, sheet appearance, solvent resistance, heat resistance, impact resistance, and rigidity.

Next, the sample sheet was cut into 500 square square pieces, and each sheet piece was developed at a rate of 3 times (
Length 450mm x Width 400mm x Height 212affi) and 5 times (Length 450m1 x H1400III x Height 4
24 l) was deep drawn into a rectangular cylinder with a bottom.

The vacuum/pressure forming method was a 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 during molding at a development rate of 5 times, and the thickness retention of each sample piece was measured at a development rate of 3 times. Measurements were made during molding, and the results are summarized in the table below.

In addition, sample No. 3.4.8.9.13.14.15
, and 18 are comparative examples, and the values of the components marked with * are outside the scope of the present invention.

(Left below) Measuring method of physical properties (i) Sheet formability was determined by extrusion molding to 71P1.
Established. That is, the extruded sheet was rated 0 if it did not exhibit layer peeling, so-called warpage, or sink marks and had an excellent discharge amount, and the rated × if it did not.

(11) Regarding the sheet appearance, the surface gloss and surface roughness of each sample sheet were observed. Those with good surface gloss and clean skin are ○, those with poor skin are ×.
And so.

(iii) Solvent resistance was evaluated by immersing each data sheet in acetone (20° C. for 3 days) to evaluate the appearance, especially the occurrence of cracks and swelling state, and rated the normal one as O and the one that was not as X.

(iv) Heat resistance was measured at a load of 18.6 kg/c- based on STM D648.

(v) Impact resistance is ASTM D 256
It was measured by the Izod method (with V notch).

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

(vil)Deep drawability is evaluated by whether there is little sagging during heating and no tearing during forming when deep drawing is performed using a vacuum/pressure forming method at a development rate of 5 times. Marked things as ×.

(V 1) The thickness retention rate 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 development magnification was 3 times. And those with a thickness retention rate of 45 to 80% are 0
Those less than 145% were marked as x.

(1x) Dimensional stability was determined by observing the external shape of the molded product made by vacuum/air pressure forming with a 5x expansion rate to see if there was any waviness or warping. .

As is clear from the above table, sample No. according to the present invention,
1.2.5.6.7.10.11.12.16.1
The resin composition of No. 7 has good sheet formability and sheet appearance, and it is possible to obtain a sheet with excellent solvent resistance, impact resistance, heat resistance, and rigidity. It has good luster and clean skin,
Furthermore, the deep drawability, thickness retention rate, and dimensional stability are extremely good, and molded products with excellent dimensional accuracy and external shape can be obtained through vacuum/pressure forming processing. Example sample No. 3.4.8.9.1
It had much better physical properties than the resin composition of No. 3.14.15.18.

Effects of the Invention As mentioned above, the molding resin composition according to the present invention has a melt flow rate (MFR, 230°C) of 10 g/10
A propylene-ethylene block copolymer (^) having an ethylene content of 1 to 20% by weight and a melt flow index (MFI, 190°C) of
High density polyethylene (B) of 10 minutes or less and a molecular weight of 20
A rubber-modified polystyrene polymer (G) having a molecular weight of 0,000 to 400,000, a styrene-butadiene block copolymer (D) having a butadiene content of 30% by weight or less, and a methacrylic ester and an acrylic ester as essential components. The relative proportion of the former is 30 to 90% by weight, while the latter is 70 to 10% by weight of the acrylic copolymer (E). 3 to 30 parts of the styrene-butadiene block copolymer (D) to 1 part of the total of the three components of the copolymer (A), high-density polyethylene (B), and rubber-modified polystyrene polymer (G), 100 ffij.
parts by weight, and 1 to 15 parts of the acrylic copolymer (E), and two components (A) and (B) out of the total of the three components (A), (B), and (G) above. The sum of 30-70
% by weight, and component (G) is 70 to 30 m feet 26, and among the sum of the two components (A) and (B), (
A) component is 10-90%, and (B) component is 90%
~10% by weight, and according to the molding resin composition of the present invention, it is possible to take advantage of the advantages of polyolefin resins and rubber-modified polystyrene resins, while compensating for their disadvantages, and is suitable for vacuum/pressure molding and extrusion. It has good sheet formability in the sheet forming method, and has excellent solvent resistance, impact resistance,
Not only can a sheet with excellent heat resistance and rigidity be obtained, but the sheet obtained has a good surface gloss, can improve surface roughness, and has a uniform skin.
The sheet has outstanding deep drawability, thickness retention, and dimensional stability in vacuum/pressure forming, and by deep drawing the sheet into a predetermined shape, it can be formed with extremely high dimensional accuracy and external shape. This has the effect that a molded product can be obtained.

that's all

Claims (1)

[Claims] Melt flow rate (MFR, 230℃) is 10g/1
0 minutes or less and a propylene-ethylene block copolymer (A) having an ethylene content of 1 to 20% by weight;
Melt flow index (MFI, 190℃) is 1g
/10 minutes or less high density polyethylene (B) and molecular weight 2
00,000 to 400,000 rubber-modified polystyrene polymer (G), a styrene-butadiene block copolymer (D) with a butadiene content of 30% by weight or less, and a methacrylic ester and an acrylic ester as essential components, and both The relative blending ratio of the former is 30 to 90% by weight.
In contrast, 70 to 10% by weight of the latter is blended with the acrylic copolymer (E), and the blending ratio of these is as follows: propylene-ethylene block copolymer (A), high-density polyethylene ( 3 to 30 parts by weight of the styrene-butadiene block copolymer (D) to a total of 100 parts by weight of the three components B) and the rubber-modified polystyrene polymer (G).
parts by weight, and 1 to 15 parts by weight of the acrylic copolymer (E), and two components (A) and (B) out of the total of the three components (A), (B), and (G) above. Component (G) is 70 to 30% by weight, and of the total of the two components (A) and (B), component (A) is 10 to 90% by weight, and a molding resin composition containing 90 to 10% by weight of component (B).