JPH06313091A - Molded product excellent in freon resistance - Google Patents

Abstract

PURPOSE:To obtain a molded product excellent in Freon resistance, high in impact resistance, and suitable for refrigerator interiors. CONSTITUTION:This molded product is composed of a resin composition comprising ABS resin, AS resin, a polyamide resin, and a carboxylic acid-containing modified styrenic resin. Since the molded product is excellent in Freon resistance and high in impact resistance and is easily produced by a molding method such as an extrusion molding method, a vacuum molding method or an injection molding method, the molded product is extremely useful as an inner box such as a refrigerator inner box or an inner box in cooler box and in which HCFC-141b and/or HCFC-123 are used as main foaming agents for rigid polyurethane foams.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to chemical resistance, particularly hydrochlorocarbons (hereinafter abbreviated as HCFC) such as H.
The present invention relates to a molded product which is made of a resin composition having excellent resistance to CFC-141b and is suitable for interior door materials such as refrigerator inner boxes and frame materials.

[0002]

2. Description of the Related Art In a recent refrigerator body, a rigid polyurethane foam stock solution is injected into a space formed in both boxes formed by connecting an inner box and an outer box to solidify the foam (hereinafter, in-
It is formed as a heat-insulating box body by the in situ foaming method). Further, also in the door of the refrigerator, a rigid polyurethane foam is filled by an in-situ foaming method into a space formed by combining the interior and the outer frame to form a heat insulator.

Conventionally, a general-purpose ABS resin has been mainly used for the inner box of the refrigerator. Here, a general-purpose ABS resin is obtained by polymerizing a monomer mixture of 10 to 40% by weight of a vinyl cyanide compound and 60 to 90% by weight of an aromatic vinyl compound in the presence of a conjugated diene rubber. Of the conjugated diene rubber component, or a graft copolymer, or a mixture of a vinyl cyanide compound / aromatic vinyl compound copolymer having a vinyl cyanide compound content of 10 to 40% by weight in the graft copolymer. A resin composition having a content of 10 to 20% by weight.

The reason why the ABS resin has been used in the inner box of the refrigerator is that the physical property balance between rigidity and impact resistance is high, easy vacuum moldability, appearance having excellent luster, and blowing agent for rigid polyurethane foam. And CFC-11 (trichloromonofluoromethane), which has a stress crack resistance.
That is, first, the inner box of the refrigerator is manufactured by a so-called vacuum (pneumatic) molding method in which a flat plate of a thermoplastic resin is heated and softened and shaped along the mold with an air pressure of 1 to ⁴ kg / cm ^2. Therefore, the resin for the inner box is required to have an easy vacuum forming property, specifically, a property of maintaining an appropriate viscoelasticity over a wide temperature range. Also, the average thickness of the inner box obtained by vacuum forming is less than 1mm, so the inner box resin has high rigidity and impact resistance in order to avoid deformation and cracking due to the force when incorporating it into the outer box. Both are required.

An inner box made of ABS resin is combined with an outer box made of an iron plate in a space formed in-situ.
When the rigid polyurethane foam is filled by the foaming method, the rigid polyurethane foam adheres to the ABS resin and the iron plate, so that stress due to the difference in the linear expansion coefficient of the iron plate / hard polyurethane foam / ABS resin and the temperature difference is generated when the refrigerator is operating. Therefore, it is necessary for the resin for the inner box to have stress crack resistance against CFC-11, which is a foaming agent for rigid polyurethane foam. Further, since a skin of rigid polyurethane foam that is hard and brittle at low temperatures is formed on the surface of the inner box to cause a notch effect, a high temperature low temperature Izod impact value is required for the interior resin. Moreover, good gloss is needed to make the refrigerator look good.

[0006]

CFC-11, which is a foaming agent for rigid polyurethane foams, is suspected of destroying the stratospheric ozone layer because it contains chlorine and is hardly decomposable. There is a trend towards restricted use. Therefore, HCFC-123 (1-hydro-1,1-dichloro-2,2-trifluoroethane) and / or as a foaming agent for rigid polyurethane foam replacing CFC-11
Alternatively, HCFC-141b (1,1,1-trihydro-2,
2-dichloro-2-fluoroethane) is about to be used, but since these all have a higher dissolving power for ABS resin than CFC-11, HCFC-123 and / or
Alternatively, A of a refrigerator filled with rigid polyurethane foam by in-situ foaming method using HCFC-141b
The inner box made of BS resin easily crazes or cracks under stress and loses the commercial value of the refrigerator. on the other hand,
Polyamide compound is widely used as a material having excellent chemical resistance, but the molding processability in forming the refrigerator inner box and door interior material which is about to be used in the present invention, that is, the vacuum forming property. Was difficult due to its viscoelasticity.

That is, the object of the present invention is to have excellent chemical resistance, particularly excellent chlorofluorocarbon (HCFC) resistance and thermal stability, and to facilitate extrusion molding, vacuum molding and injection molding like ordinary ABS resins. The goal is to find a resin material that is industrially easy to use.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a resin composition containing an ABS resin, an AS resin, a polyamide resin and a carboxylic acid-containing modified styrene resin is a fluorocarbon compound, particularly HCFC-123,14
It has extremely high stress cracking resistance in the presence of HCFC such as 1b, and at the same time has easy vacuum forming properties even though it contains a polyamide compound, and has high physical properties and a good appearance. The present invention has been found to be useful for an inner box of a refrigerator and a door interior material using a foaming agent, and has completed the present invention.

That is, the present invention comprises: a. Polymerizing 30-90 parts by weight of a monomer mixture consisting of 15-45% by weight of a vinyl cyanide compound and 55-85% by weight of an aromatic vinyl compound in the presence of 10-70 parts by weight of a conjugated diene rubber. 1 to 90% by weight of the resulting graft copolymer (A), b. Copolymer (B) obtained by polymerizing a monomer mixture consisting of 15 to 45% by weight of a vinyl cyanide compound and 55 to 85% by weight of an aromatic vinyl compound (B), 0 to 90% by weight, c. Polyamide resin 10 to 80% by weight, d. The present invention relates to a molded article having excellent chlorofluorocarbon resistance, which is composed of a thermoplastic resin composition containing 0.1 to 40% by weight of a modified styrene resin copolymerized with a carboxylic acid-containing unsaturated compound as an essential component.

Further, the molded product of the present invention is characterized by being excellent in strength, particularly impact resistance, and having good vacuum moldability and appearance.

The present invention will be specifically described below.

The graft copolymer (A) used in the present invention means 15 to 45% by weight of vinyl cyanide-based monomer and 55 of aromatic vinyl-based monomer in the presence of 10 to 70 parts by weight of diene rubber. ~ 85
% By weight and other vinylic monomers copolymerizable therewith 0
It means a graft copolymer obtained by copolymerizing 30 to 90 parts by weight of a monomer mixture consisting of 30 to 30% by weight.

The diene rubber referred to here is polybutadiene (PBD), styrene-butadiene copolymer rubber (S
BR) and the like.

Examples of vinyl cyanide monomers include acrylonitrile (AN) and methacrylonitrile, with AN being preferred.

Examples of the aromatic vinyl monomer include styrene (ST), α-methylstyrene, ρ-methylstyrene and the like, and these can be used in combination.

Examples of vinyl monomers copolymerizable with vinyl cyanide monomers and aromatic vinyl monomers include methyl (meth) acrylate and butyl acrylate.

In the present invention, in order to obtain a resin composition having excellent physical properties and vacuum moldability, the graft copolymer (A) is used.
It is preferable that the constituent ratio of each component is within the above range. The amount of diene rubber in the graft copolymer (A) is 70
If the amount is more than parts by weight, the moldability of the final composition will be poor. or,
If the amount of rubber is less than 10 parts by weight, the mechanical properties of the final composition,
In particular, the impact resistance becomes low. Further, the graft copolymer (A)
When the amount of the aromatic vinyl-based monomer in the monomer mixture forming the matrix resin exceeds 85% by weight, the physical properties of the graft copolymer (A) are deteriorated. If the amount of the monomer exceeds 45% by weight, the resin composition becomes non-uniform and the resin tends to be colored. Other vinyl monomers that can be copolymerized with vinyl cyanide monomers and aromatic vinyl monomers are
It should be 30% by weight or less. If it exceeds 30% by weight, physical properties of the graft copolymer (A), particularly impact resistance and fluidity are deteriorated.

As the method for producing the graft copolymer (A), known emulsion polymerization method, bulk suspension polymerization method or solution polymerization method can be mentioned. In particular, the emulsion polymerization method using a rubber latex is used for blending workability later. Is more preferable because it is good.

The copolymer (B) used in the present invention means vinyl cyanide monomer 15 to 45% by weight, aromatic vinyl monomer 55 to 85% by weight and other copolymerizable with these. It is a copolymer of a monomer mixture consisting of 0 to 30% by weight of a vinyl monomer.

Examples of the vinyl cyanide-based monomer in the above copolymer (B) include acrylonitrile (AN) and methacrylonitrile, with AN being preferred.

Examples of the aromatic vinyl monomer include styrene (ST), α-methylstyrene, β-methylstyrene and the like, and these can be used in combination.

Examples of vinyl monomers copolymerizable with vinyl cyanide monomers and aromatic vinyl monomers include methyl (meth) acrylate and butyl acrylate.

When the amount of the aromatic vinyl monomer in the copolymer (B) is less than 55% by weight, the copolymer (B) becomes brittle,
On the other hand, when it exceeds 85% by weight, the thermal stability of the resin is deteriorated. On the other hand, when the amount of the vinyl cyanide-based monomer is less than 15% by weight, the chemical resistance of the copolymer (B) is low, and when it exceeds 45% by weight, the moldability is deteriorated. Further, the amount of the third component monomer should be at most 30% by weight or less, and if it is copolymerized more than that, the fluidity becomes worse.

Further, as a method for producing the copolymer (B),
There are emulsion polymerization method, suspension polymerization method, bulk polymerization method and the like, but any polymerization method may be used.

When a mixture of the graft copolymer (A) and the copolymer (B) is used in the present invention, the mixing ratio on a weight basis is (A) / (B) = 100/0.
20/80 range should be selected. As long as it is within this mixing ratio range, there are no particular restrictions on the mixing method.

The ratio of (A) / (B) is 100/0 to 20/80
Outside of this range, the physical properties of the final composition, especially the impact resistance, will be low, and it is not suitable as the material resin which is the object of the present invention.

The type of the polyamide resin used in the present invention is not limited at all, but for example, polyε-caprolactam (polyamide-6), polyhexameleneadipamide (polyamide-6,6), polyamide-4, 6 and the like are exemplified, and they can be used in combination. As will be described later, it is more desirable to add a compatibilizer in order to further improve strength such as impact strength, but the amount of amino terminal groups in the polyamide resin at that time is preferably 0.010 to 0.100 mmol / g. . This amount can be quantified by ¹ H-NMR or a titration method, but if the terminal amino group content is 0.010 mmol / g or less, the reactivity with the resin described in the next section is poor and the physical properties of the final composition, especially the impact resistance, are low. Low. The amount of amino end groups is 0.
When it is 100 mmol / g or more, the moldability (melt flowability) and thermal stability of the final composition are deteriorated, which is not preferable.

Furthermore, the polymerization degree of this polyamide resin is the relative viscosity (ηrel) of a solution of 96% sulfuric acid dissolved at a concentration of 1 g / dl.
Is preferably 2.0 to 7.0 at 25 ° C, and ηrel is 2.
When it is 0 or less, the physical properties of the final composition, particularly impact resistance, are low.

The modified styrenic resin used in the present invention is as follows. 1) Obtained by polymerizing an aromatic vinyl compound or a monomer comprising an aromatic vinyl compound and a carboxylic acid-containing unsaturated compound in the presence of a rubbery polymer obtained by copolymerizing a carboxylic acid-containing unsaturated compound. Graft copolymer, 2) Graft copolymer obtained by copolymerizing a monomer composed of an aromatic vinyl compound and a carboxylic acid-containing unsaturated compound in the presence of a rubbery polymer, 3) Carboxylic acid-containing A mixture of a rubber-reinforced styrene resin in which an unsaturated compound is not copolymerized and a copolymer of a monomer containing a carboxylic acid-containing unsaturated compound and an aromatic vinyl compound as an essential component, 4) above 1) or 2) And a mixture of a carboxylic acid-containing unsaturated compound and a copolymer composed of an aromatic vinyl compound, 5) the above 1), 2), 3) or 4) and a copolymer containing an aromatic vinyl compound as an essential component mixture There is a thing.

In the above 1) to 5), styrene is preferable as the aromatic vinyl compound, and acrylonitrile is preferable as the monomer copolymerized with the aromatic vinyl compound. Polybutadiene is preferred as the rubbery polymer,
As the carboxylic acid-containing unsaturated compound, acrylic acid, methacrylic acid and (iso) crotonic acid are preferable.

The unsaturated compound containing carboxylic acid is 0.1 to 8% by weight, preferably 0.2 to 4% by weight, in the component (d).
More preferably, it is 1 to 4% by weight. If it is less than 0.1% by weight, the impact resistance is low, and if it exceeds 8% by weight, the impact resistance, molding processability and molding appearance are poor. The content of the carboxylic acid-containing unsaturated compound in the entire composition is 0.0001 to 3.2% by weight, preferably 0.002 to 0.8% by weight, more preferably 0.02 to 0.6% by weight. If it is less than 0.0001% by weight, impact resistance is low, and if it exceeds 3.2% by weight, impact resistance, molding processability, weld strength, and molding appearance are deteriorated.

The rubber content in the total composition is 5 to 40% by weight, preferably 7 to 35% by weight, more preferably 7 to 35% by weight.
30% by weight. If it is less than 5% by weight, impact resistance and weld strength are low. If it exceeds 40% by weight, moldability is poor.

In the composition of the present invention, the content of the graft copolymer (A) is 1 to 90% by weight, preferably 10 to 90% by weight, more preferably 10 to 80% by weight. If it is less than 1% by weight, impact resistance is poor, and if it exceeds 90% by weight, the molding appearance and molding processability are poor.

The content of the copolymer (B) is 0 to 90% by weight, preferably 20 to 80% by weight. If it is more than 90 parts by weight, the chemical resistance of the final composition, particularly the CFC resistance, is not sufficiently exhibited.

The amount of the polyamide resin used is 10 to 80% by weight, preferably 20 to 80% by weight. If it is less than 10% by weight, the chemical resistance of the final composition, especially the CFC resistance, is not sufficient, and if it exceeds 80% by weight, physical properties such as impact resistance deteriorate, and further, the vacuum of the sheet made of the final composition. Molding becomes impossible.

The modified styrenic resin is 0.1 to 40% by weight, preferably 1 to 20% by weight. If it is less than 0.1% by weight, the impact resistance is significantly reduced and the strength is insufficient.
If it exceeds 40% by weight, fluidity may decrease.
Decomposition during molding is likely to occur.

The above components may be blended by melt kneading using an extruder, kneader, roll or the like.

A preferred method is a method in which powdered raw materials are mixed using a Henschel mixer or the like, and this is heated and melted using an extruder to be extruded and pelletized.

In the present invention, various additives usually used in the final composition, such as a plasticizer, an antioxidant,
Stabilizers, pigments, dyes, etc. may be added.

The composition thus obtained is
The intended refrigerator interior member can be formed by producing a sheet by extrusion and then performing vacuum forming. In this case, in order to form an interior member having high gloss, it is necessary that the sheet has high gloss, and it is more desirable to use a mirror-finished roll as the glazing roll during the sheet extrusion.

When a door cap component or the like is to be produced by injection molding, it is necessary for the mold to have a mirror finish in order to obtain a molded product having high gloss.

[0042]

EXAMPLES Examples of the present invention will be described below in detail. However, the present invention is not limited to these examples. All parts and% in the examples are based on weight.

The types of the graft copolymer (A), the copolymer (B), the polyamide resin and the modified styrene resin used in the present invention are shown in Tables 1 to 4.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

Further, in Examples 1 to 10 and Comparative Examples 1 to 3, suitability as a refrigerator inner box was evaluated by the following 5 items.

(1) Tensile Elongation Measured according to ASTM D638.

(2) Flexural Modulus Measured according to ASTM D790. The flexural modulus required to avoid deformation of the inner box is considered to be 20,000 kg / cm ² .

(3) Izod impact strength It was measured according to ASTM D256. The value required to prevent cracking when incorporating the inner box into the outer box is 12 kg ・ cm / cm
it is conceivable that.

(4) Vacuum forming Using a cup-shaped mold with a frontage diameter of 100 mm, a bottom surface diameter of 80 mm and a depth of 100 mm and a draw ratio of 1: 1, a thickness of 2.5 mm.
Sheet was vacuum formed. The moldability was determined by visually observing the wall thickness distribution, the bottom corner radius, and the gloss of the obtained molded product. ◯: The gloss of the molded product is good and there is no wall thickness distribution. Δ: The gloss of the molded product is good, but there is some distribution in the wall thickness. X: The gloss of the molded product is insufficient and the wall thickness has a distribution. Yes, there is a problem in use.

(5) The critical strain value 35 mm × 230 mm × 0.7 mm strip-shaped compression-molded test piece was set on a 1/4 inch elliptical jig. HCFC-
The test piece was allowed to stand for 12 hours in an atmosphere of 123 or HCFC-141b, and the crack generation state of the test piece was observed. ◯: No crack was generated at all and there was no problem in use. Δ: No crack was generated, but the gloss of the test piece was lost. X: Crack was generated and it was considered difficult to use.

Example 1 25 parts of graft copolymer (ABS resin) (A-1), 25 parts of copolymer (AS resin) (B-1), polyamide resin (C-1; Unitika Ltd.) A1030BRL manufactured by A1030BRL) to 100 parts by weight of 50 parts, and modified styrene resin (D-1)
10 parts by weight, and 0.1 part of each of an antioxidant (Irganox 1010 manufactured by Ciba-Geigy Co., Ltd.) and a lubricant (ethylenebisstearic acid amide) were added, and a V-type blender was used to add 20 parts.
Dry blended for minutes. The blended resin mixture was kneaded and extruded at 230 ° C. using a 40 mmφ single screw extruder manufactured by Osaka Seiki Co., Ltd. No bent-up or surging was observed during extrusion. The extruded strand was cooled in a water bath and pelletized. The pellets were dried in a hot air drier at 90 ° C. for 4 hours before injection molding or extrusion and subsequent vacuum molding.

The injection molding was carried out by molding a test piece for physical property evaluation with an injection molding machine TS-100 manufactured by Nissei Plastic Industry Co., Ltd. The molding conditions were a cylinder temperature of 230 ° C, a mold temperature of 60 ° C, and a molding cycle of injection for 15 seconds and cooling for 30 seconds. The test specimens are ASTM dumbbell (No. 2) for tensile test, and 1/4 "bar for bending test and Izod impact test.

The extruded sheet is 65 mmφ manufactured by Ikegai Iron Works Co., Ltd.
Sheet extrusion was performed at 230 ° C. using a single-screw extruder.
The T-die used is 2.5 mm thick and 500 mm wide.
The thickness of the sheet was controlled by the distance between the rolls. Thus, a sheet having a thickness of 2.3 to 2.5 mm and a width of 450 mm was obtained.

The vacuum forming was carried out by a vacuum forming machine manufactured by Asano Laboratory Co., Ltd. The above-mentioned sheet was cut into 450 mm square.
The mold has a frontage diameter of 100 mm, a bottom surface diameter of 80 mm, and a depth of 10
A cup-shaped mold having a 0 mm reduction ratio of 1: 1 was used.
The heating temperature was 200 ° C and the mold temperature was 80 ° C. A test piece for critical strain was obtained by compression molding into a strip of 35 mm × 230 mm × 0.7 mm.

Table 5 shows the results of evaluation of the physical properties, moldability and chlorofluorocarbon resistance using the test pieces thus obtained. It had high impact resistance, good moldability, and sufficient CFC resistance. Moreover, the gloss was good, and no gel was found in the molded product, and the appearance was good.

Example 2 The procedure of Example 1 was repeated except that the modified styrenic resin was changed to D-2. The results are shown in Table 5.

Example 3 Without using AS resin, 50 parts of ABS resin (A-1) and 50 parts of polyamide (C-1) were added to 100 parts by weight of modified styrenic resin (D-1). The same procedure as in Example 1 was performed except that 10 parts by weight was added. In particular, the impact resistance and the tensile elongation were increased, and the moldability was further improved. The results are shown in Table 5.

COMPARATIVE EXAMPLE 1 In Example 1, the modified styrene resin was not used, and ABS was used.
This is an example in which only resin, AS resin, and polyamide resin are used. The compatibility between the ABS resin or AS resin and the polyamide resin was poor, and the impact resistance and the tensile elongation were remarkably lowered. In addition, when a peeling test was performed on the injection molded product or the sheet with cellophane tape or the like, it was clear that the resin skin layer peeled off and the compatibility was poor. In addition, the critical strain value also decreased because the toughness of the resin was insufficient. The results are shown in Table 5.

[0062]

[Table 5]

Example 4 Example 4 was repeated except that the AS resin (B-1) was changed to the AS resin (B-2) having a high acrylonitrile copolymerization ratio. The physical properties, chlorofluorocarbon resistance, and vacuum formability are shown in Example 1.
Was almost the same as. The results are shown in Table 6.

Examples 5 and 6 are examples in which the type of ABS resin in the composition was changed. Here, ABS (A-2), which has a low rubber content instead of A-1,
Alternatively, Example 1 was used except that ABS (A-3) having a high acrylonitrile copolymerization ratio in the ABS matrix was used.
I went the same way. All of them had good strength, moldability and CFC resistance. The results are shown in Table 6.

Examples 7 and 8 are examples in which the type of polyamide resin in the composition was changed. Instead of nylon resin C-1, nylon (C-2) having a higher molecular weight than C-1 or nylon-66 resin (C-
Example 1 was repeated except that 3) was used. C-
When 2 was used, the melt viscosity was increased and the vacuum moldability was further improved. The strength and chlorofluorocarbon resistance were similarly good (Example 7). When C-3 is used, nylon-66
Since the melting point of was high, the molding temperature and the processing temperature were high, but the strength and CFC resistance were good (Example 8).
The results are shown in Table 6.

[0066]

[Table 6]

Examples 9 and 10 The amount of polyamide which affects the CFC resistance and the vacuum formability was examined. That is, in Examples 9 and 10, the amounts of polyamide in the resin composition were 30 parts by weight and 70 parts by weight, respectively. Example 9
In comparison with Example 1, the vacuum moldability was further improved. However, due to the decrease in the amount of polyamide, the CFC resistance was slightly reduced. On the other hand, in Example 10 containing a large amount of polyamide, on the contrary, the chlorofluorocarbon resistance was high. As for the vacuum forming, the forming / processing temperature was slightly higher than that of Example 1, but a good product was obtained. The results are shown in Table 7.

Comparative Examples 2 and 3 In Comparative Example 2, the ABS / AS composition was tested, and in Comparative Example 3, the polyamide resin carrier was tested for vacuum moldability, flon resistance and physical properties. The vacuum moldability and strength of the ABS / AS resin composition were good, but the fluorocarbon resistance, especially HCFC-141b or HCFC-
There was no resistance to 123, and a large amount of cracks were generated in the sample after the critical strain test (Comparative Example 2). On the other hand, the polyamide resin was good in pellet extrusion and subsequent sheet extrusion and injection molding, but could not be vacuum formed at all. That is, at a temperature below the melting point of nylon-6 (220 to 230 ° C), the stretching of the sheet was insufficient and a molded product having a predetermined shape could not be obtained. Above the melting point, the resin was completely melted and flowed, so that vacuum molding could not be performed. The results are shown in Table 7.

[0069]

[Table 7]

[0070]

The molded article of the present invention has excellent chlorofluorocarbon resistance, high impact resistance, and can be easily obtained by molding such as extrusion molding, vacuum molding, and injection molding.
It is extremely useful as an inner box for refrigerator interiors, cooler box interiors, etc. using 141b and / or HCFC-123 as the main foaming agent for rigid polyurethane foam.

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Claims (1)

[Claims] 1. A. Monomer mixture of 15-45% by weight vinyl cyanide compound and 55-85% by weight aromatic vinyl compound in the presence of 10-70 parts by weight of conjugated diene rubber 30-
Graft copolymer (A) obtained by polymerizing 90 parts by weight
1 to 90% by weight, b. Copolymer (B) obtained by polymerizing a monomer mixture consisting of 15 to 45% by weight of a vinyl cyanide compound and 55 to 85% by weight of an aromatic vinyl compound (B), 0 to 90% by weight, c. Polyamide resin 10 to 80% by weight, d. A molded article having excellent chlorofluorocarbon resistance, which is composed of a thermoplastic resin composition containing 0.1 to 40% by weight of a modified styrene resin copolymerized with a carboxylic acid-containing unsaturated compound as an essential component.