JPH11192638A - Injection-molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection-molded article low in head impact coefficient(HIC), not generating a crack at the time of impact, further, high in thermal deformation resistance and excellent in appearance (surface properties). SOLUTION: An injection-molded article comprises a thermoplastic resin compsn. consisting of (1) an acrylic ester copolymer 5-65 pts.wt., (II) a maleimide copolymer 15-80 pts.wt., (III) a graft copolymer 5-75 pts.wt. and (IV) other thermoplastic resin 0-50 pts. wt. [the sum total of (I), (II), (III) and (IV) is 100 pts.wt.] and the phase structure observed by a transmission microscope in the cross section parallel to a resin flow direction at a depth of 5 μm from the surface of the molded article has stripe parts (A) with an average width of 0.0005-10 μm, an island parts (B) with an average particle size of 0.005-2 μm and sea like parts (C) other than the stripe parts (A) and the island parts (B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a head impact index (H)
The present invention relates to an injection molded article having a low IC), no surface cracks upon impact, high heat deformation resistance, and excellent appearance (surface properties).

[0002]

2. Description of the Related Art In recent years, especially in interior and exterior resin parts of automobiles, in addition to characteristics such as dimensional stability and surface appearance at high temperatures, as well as characteristics relating to safety at the time of collision as seen in side collision regulations in the United States and the like. There is a demand for improvement. In other words, as interior / exterior resin parts in the side collision regulation, the head impact index (HIC) is low, there is no surface cracking at impact, the heat resistance deformation is high, and the appearance (surface properties) is high. Excellent resin is required.
Incidentally, the head impact index in FMVSS is defined as the maximum value of the integrated value of the acceleration change for a certain period of time.

As a resin composition used for a molded article, for example, Japanese Patent Application Laid-Open No. Sho 59-20346 discloses a method in which a specific plasticizer is added to a rubber-reinforced styrene resin. Also, there is volatilization of the plasticizer, which is not satisfactory. Although the use of a polypropylene resin having a specific composition is also being studied, it has drawbacks such as poor surface appearance of the molded article due to sink marks, poor dimensional stability due to warpage, and poor adhesion to other materials.

Further, a composition of an ABS resin and an acrylate copolymer has been disclosed in Japanese Patent Application Laid-Open No. Sho 58-17925.
No. 7 discloses a composition comprising a rubber-containing styrenic resin and an acrylic ester copolymer having a high gel content, and JP-A-63-17954 discloses a composition comprising a rubber-containing maleimide-styrene copolymer and an ABS resin. It is described that a composition comprising an acrylate copolymer improves chemical resistance. However, in these compositions H
High IC value, surface cracks and poor surface appearance upon impact are observed, low HIC value, which is the object of the present invention, no surface cracks upon impact, higher heat resistance, and better appearance (surface properties) An excellent injection molded article cannot be obtained.

Further, the composition comprising a rubber-containing maleimide-styrene copolymer and an acrylic ester copolymer described in JP-A-8-27336 also has an HIC value which is an object of the present invention. A molded article which is low, does not have surface cracks upon impact, and has excellent appearance (surface properties) cannot be obtained.

[0006]

SUMMARY OF THE INVENTION The present invention has solved the above-mentioned problems and has a low head impact index (HIC) of a molded product.
And there is no surface crack at the time of impact, furthermore high heat deformation resistance,
It is an object of the present invention to provide an injection molded article having excellent appearance (surface properties).

[0007]

In order to reduce the HIC value, prevent surface cracks upon impact, increase heat-resistant deformation, and improve the appearance (surface properties), the present inventors have proposed a rubber composition. The matrix in the composition comprising the maleimide-styrene-based copolymer and the acrylate-based copolymer is graft copolymerized on a matrix obtained by microphase-separating the maleimide-styrene-based copolymer and the acrylate-based copolymer. We believe that it is necessary to have a polymer alloy structure in which the polymer (rubber) exists as islands. Furthermore, the HIC value is low, the impact resistance is high, the heat deformation resistance is high, and the appearance (surface properties) is further improved. In order to improve the efficiency efficiently, the maleimide-styrene copolymer and acrylate copolymer have a special phase structure that delicately controls the microphase separation, and have a uniform shape. Out of the molded body is thought to be necessary.

The inventors of the present invention have conducted intensive studies from such a viewpoint, and as a result, have found that the acrylate copolymer (I), the maleimide copolymer (II), and the graft copolymer (II)
The injection molded article having a special phase structure and a specific shape made of a resin composition having a specific composition comprising I) has a low HIC value, no surface cracks upon impact, high heat deformation resistance, and The inventors have found that the appearance (surface properties) is excellent, and have reached the present invention.

That is, according to the present invention, 5 to 65 parts by weight of an acrylate-based copolymer (I), 15 to 80 parts by weight of a maleimide-based copolymer (II), and 5 to 65 parts by weight of a graft copolymer (III)
A thermoplastic resin composition comprising 75 parts by weight and 0 to 50 parts by weight of another thermoplastic resin (IV) [(I), (II), (II)
I) and (IV) 100 parts by weight in total], and the phase structure observed by a transmission electron microscope in a section parallel to the resin flow direction at a depth of 5 μm from the surface of the molded product has an average width of 0.0005. Streaks (A) of 10 to 10 μm and average particle size of 0.
005 to 2 μm islands (B) and the (A), (B)
An injection-molded article characterized by having a sea-like portion (C) other than the above.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic resin composition used for the molded article of the present invention contains 5 to 65 parts by weight, preferably 8 to 55 parts by weight, more preferably, 5 to 65 parts by weight of an acrylate copolymer (I). 10 to 45 parts by weight, 15 to 80 parts by weight of the maleimide copolymer (II), preferably 18 to 70 parts by weight, more preferably 20 to 65 parts by weight, 5 to 75 parts by weight of the graft copolymer (III), Preferably 10 to 60 parts by weight, more preferably 15 to 50 parts by weight, and other thermoplastic resin (IV) 0 to 50 parts by weight, preferably 0 to 40 parts by weight, more preferably 0 to 30 parts by weight [( I), (II),
(III) and (IV) in total of 100 parts by weight]. If the acrylate copolymer (I) is less than 5 parts by weight, HI
If the C value increases and exceeds 65 parts by weight, heat resistance decreases and surface cracking upon impact tends to occur (hereinafter, referred to as “C”).
It may be described as "surface cracking property at impact is reduced"). If the amount of the maleimide-based copolymer (II) exceeds 80 parts by weight, the HIC value increases, and if it is less than 15 parts by weight, the heat resistance decreases. When the amount of the graft copolymer (III) is less than 5 parts by weight, the HIC value becomes high, and the surface cracking property at the time of impact is reduced. When it exceeds 75 parts by weight, heat resistance and appearance are reduced.
If other thermoplastic resin (IV) exceeds 50 parts by weight, HIC
The value increases, and the surface cracking property upon impact decreases.

In the molded article of the present invention, the phase structure observed by a transmission electron microscope in a section parallel to the resin flow direction at a depth of 5 μm from the surface of the molded article has an average width of 0.0005 to 0.0005.
10 μm streaks (A) and average particle size 0.005 to 2 μm
(B) and a sea-like portion (C) other than the above (A) and (B). The phase structure has an average width of 0.0008 to 5 μm in order to reduce the HIC value and reduce surface cracking upon impact.
(A), an island-shaped portion (B) having an average particle size of 0.01 to 1.5 μm, and a sea-shaped portion (C) other than (A) and (B).
Are preferable, and the average width is 0.001 to 3
Particularly, a phase structure having a streak portion (A) of μm, an island portion (B) having an average particle size of 0.15 to 1.0 μm, and a sea portion (C) other than the above (A) and (B) is particularly preferable. preferable. According to transmission electron microscopy observation (degree of staining), the streak portion (A) is mainly composed of the acrylate copolymer (I), and the island portion (B) is the graft copolymer (III). It is considered that the sea-like portion (C) is a main component and the maleimide-based copolymer (II) is a main component.

The acrylate copolymer (I) in the present invention is a portion used for lowering the HIC value and increasing the impact resistance, and is a preferred acrylate copolymer (I). The acrylate is 40 to 85% by weight, preferably 50 to 80% by weight, more preferably 55 to 80% by weight in terms of HIC value and surface cracking at impact.
75% by weight, 15 to 40% by weight of a vinyl cyanide compound, preferably 20 to 35% by weight, more preferably 20 to 30% by weight from the viewpoint of surface cracking upon impact, and 0 to 45% by weight of an aromatic vinyl compound. , Preferably 0 in terms of appearance.
To 30% by weight, more preferably 2 to 25% by weight, and 0 to 30% by weight, preferably 0 to 20% by weight, more preferably 0 to 10% by weight of monomers copolymerizable therewith (total 100%). % By weight).

When the content of the acrylate is less than 40% by weight, the HIC value is high, and the surface cracks easily occur upon impact.
If it exceeds 85% by weight, the heat-resistant deformation property is low, and it is easy to peel off. When the content of the vinyl cyanide compound is less than 15% by weight, the compound is easily peeled off, and the HIC value becomes high.
If it exceeds 300, it is easy to peel off, the HIC value is high, and surface cracking at the time of impact tends to occur. If the content of the aromatic vinyl compound exceeds 45% by weight, the impact resistance tends to be low and the HIC value tends to be high. Further, when the amount of the copolymerizable monomer exceeds 30% by weight, the HIC is high, and surface cracking at the time of impact tends to occur.

The T of the acrylate copolymer (I)
g (glass transition temperature) is preferably 20 ° C. or less, more preferably 0 ° C. or less, and still more preferably −10 ° C. or less from the viewpoint of the HIC value. If it exceeds 20 ° C., the HIC value tends to increase. Acrylic ester copolymer (I)
Gel content [gel content is defined as methyl ethyl ketone 2
% Solution was allowed to stand at 23 ° C. for 24 hours, filtered through a 100-mesh wire gauze, and the filtration residue was dried. The value was expressed by (weight of filtration residue / weight of original copolymer) × 100. ] Is preferably 10% by weight or less, more preferably 5% by weight or less, and still more preferably 3% by weight or less from the viewpoint of processability. If it exceeds 10% by weight, moldability tends to decrease. Further, the reduced viscosity (30 ° C., in N, N-dimethylformamide solution) of the methyl ethyl ketone soluble portion of the acrylate copolymer (I) is preferably 0.3 to 0.3.
1.2 dl / g, more preferably 0.4 to 1.0 dl / g,
More preferably, it is 0.45 to 0.9 dl / g. 0.3
If it is less than dl / g, the impact resistance tends to decrease, and if it exceeds 1.2 dl / g, the workability tends to decrease.

As the acrylate, methyl acrylate, ethyl acrylate, butyl acrylate,
Examples include 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, 2-hydroxyethyl acrylate, and glycidyl acrylate.
Of these, butyl acrylate is preferred from an industrial point of view. These may be used alone or in combination of two or more. Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile. Among them, acrylonitrile is preferable from an industrial viewpoint. These may be used alone or in combination of two or more. Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, vinylnaphthalene, chlorostyrene, and bromostyrene. Of these, styrene is preferable from an industrial viewpoint. These may be used alone or in combination of two or more. Examples of the monomer copolymerizable with the compound include acrylic acid, methacrylic acid, maleimide, and N-phenylmaleimide. These may be used alone or in combination of two or more.

In the present invention, the maleimide copolymer (I)
I) is a component used for imparting heat resistance and processability. As a preferred maleimide-based copolymer (II), 10 to 40% by weight of a vinyl cyanide compound, preferably 15 to 35% by weight 5 to 50% by weight, preferably 10 to 45% by weight of a maleimide-based compound, 10 to 85% by weight, preferably 20 to 75% by weight of an aromatic vinyl compound, and 0 to 30% by weight of a monomer copolymerizable therewith. %, Preferably 0 to 20% by weight (total 100% by weight), and is a copolymer obtained by polymerizing a monomer mixture containing at least 49 mol% of an aromatic vinyl compound. If the amount of the vinyl cyanide compound is less than 10% by weight, surface cracks are likely to occur at the time of impact, and if it exceeds 40% by weight, the processability is reduced. When the amount of the maleimide-based compound is less than 5% by weight, heat resistance is reduced, and
If it exceeds 0% by weight, the appearance will be reduced. When the amount of the aromatic vinyl compound is less than 10% by weight, the appearance is deteriorated, and 85% by weight.
If it exceeds 300, the surface cracking property upon impact is reduced. The ratio of the aromatic vinyl compound in the monomer mixture is particularly important, and the content in the monomer mixture should be 49 mol% or more, preferably 5 mol% or more.
0 mol% or more. When the ratio of the aromatic vinyl compound is 49
If the amount is less than mol%, thermal stability, surface cracking properties upon impact, and appearance are significantly reduced.

The maleimide copolymer (II) preferably has a reduced viscosity (30 ° C., in an N, N-dimethylformamide solution) of a methyl ethyl ketone-soluble component from the viewpoint of surface cracking properties and appearance upon impact. 0.3 to 1.2 dl / g, more preferably 0.35 to 1.0 dl / g, still more preferably 0.3 to 1.0 dl / g.
4 to 0.9 dl / g. If it is less than 0.3 dl / g, impact resistance tends to decrease, and if it exceeds 1.2 dl / g, workability tends to decrease.

Acrylonitrile, methacrylonitrile and the like are used as the vinyl cyanide compound of the maleimide copolymer (II), and styrene and styrene are used as the aromatic vinyl compound.
α-methyl styrene, p-methyl styrene, p-isopropyl styrene, chloro styrene, bromo styrene, vinyl naphthalene and the like, and maleimide compounds such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, -Butyl maleimide,
N-phenylmaleimide, N- (p-methylphenyl)
Maleimide and the like. From an industrial point of view, acrylonitrile is particularly preferred as the vinyl cyanide compound, styrene as the aromatic vinyl compound, and N-phenylmaleimide as the maleimide compound. These may be used alone or in combination of two or more. Examples of the copolymerizable monomer include (meth) acrylic acid ester monomers such as methyl, ethyl, propyl, butyl, 2-hydroxylethyl, 2-ethylhexyl, and glycidyl. And the like. These may be used alone or in combination of two or more.

The graft copolymer (III) in the present invention
Is used for improving the HIC value and the surface cracking property upon impact. The rubber polymer (A) in the preferred graft copolymer (III) has a volume average particle size of 50 to 1000 nm, preferably 100 to 900 nm, and more preferably 150 to 80 nm.
0 nm, a diene rubber polymer, an olefin rubber polymer, and an acrylic rubber polymer.
Used in combination of more than one species. Volume average particle size is 50nm
Alternatively, if it exceeds 1000 nm, the impact resistance tends to decrease. Specific examples of the rubber polymer (A) include diene rubber polymers such as polybutadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, butadiene-acrylate rubber, hydrogenated styrene-butadiene rubber, and ethylene-propylene rubber. And olefin rubber polymers such as ethylene-propylene-diene rubber, and acrylic rubber polymers such as polyacrylate rubber and ethylene-acrylate rubber, and these may be used alone or in combination of two or more.

The rubber polymer (A) is preferably produced by an enlargement method using an acid group-containing latex (S). In particular, the rubber polymer (A) is composed of acrylic acid, methacrylic acid,
5 to 50% by weight of at least one unsaturated acid (c) of itaconic acid and crotonic acid, wherein the carbon number of the alkyl group is 1 to
50 to 95% by weight of at least one (meth) alkyl acrylate (d) of 12 and 0 to 40% by weight of a monomer (e) copolymerizable with (c) and (d) (total 100% by weight) )), A rubber polymer produced by a coagulation enlargement method using an acid group-containing latex prepared by polymerizing (a) is preferred. If the component (c) is less than 5% by weight, it is difficult to enlarge, and the impact resistance is reduced. If it exceeds 50% by weight, the latex tends to coagulate. If the component (d) is less than 50% by weight, the latex tends to coagulate, and if it exceeds 95% by weight, it is difficult to enlarge and the impact resistance tends to decrease. (E)
If the component exceeds 40% by weight, the latex tends to coagulate.

The preferred graft copolymer (III) comprises 10 to 90% by weight of a rubber polymer (A) and an aromatic vinyl compound.
Preferably 15 to 85% by weight, more preferably 20 to 8%.
0% by weight, at least one of (meth) acrylic acid ester and vinyl cyanide compound, 10 to 90% by weight, preferably 15%
To 85% by weight, more preferably 20 to 80% by weight, and 0 to 30% by weight, preferably 0 to 20% by weight, more preferably 0 to 15% by weight of a monomer copolymerizable therewith. And a graft portion (B) obtained by polymerizing a body mixture (100% by weight in total).
0% by weight, preferably 20 to 60% by weight, more preferably 25 to 55% by weight of the graft copolymer. Also,
The rubber polymer content is preferably 5 to 50% by weight in the resin composition. An aromatic vinyl compound in a monomer mixture,
(Meth) acrylates, vinyl cyanide compounds,
When the graft ratio of the aromatic vinyl compound and the graft copolymer and the rubber polymer content are out of the above ranges, the HIC value, the surface cracking property upon impact, and the appearance (surface properties) decrease.

Examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate.
Acrylate, glycidyl (meth) acrylate and the like can be mentioned. Of these, methyl methacrylate is preferred from an industrial point of view. These can be used alone or in combination of two or more.

Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile, and examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, p-isopropylstyrene, chlorostyrene, bromostyrene, and vinylnaphthalene. And the like,
From an industrial viewpoint, acrylonitrile is particularly preferred as the vinyl cyanide compound, and styrene is particularly preferred as the aromatic vinyl compound. These can be used alone or in combination of two or more. Examples of the copolymerizable monomer include (meth) acrylic acid, maleimide, and N-phenylmaleimide. These can be used alone or in combination of two or more.

The other thermoplastic resin (IV) in the present invention is not particularly limited, but the acrylate copolymer (I) and the maleimide copolymer (I) in the present invention are not particularly limited.
Those having an affinity for at least one of I) and the graft copolymer (III) are preferable. For example, styrene-based copolymers such as acrylonitrile-styrene copolymer, acrylonitrile-α-methylstyrene copolymer, methyl methacrylate-styrene copolymer, methyl methacrylate-ethyl acrylate copolymer, methyl methacrylate-methacrylic acid copolymer (Meth) acrylic acid ester copolymers such as coalesced copolymers are exemplified. Also, aromatic polycarbonate resin,
Polyamide resins such as nylon 6, nylon 6,6, polyester resins such as polybutylene terephthalate and polyethylene terephthalate, polyester elastomers, polyurethane elastomers, styrene block copolymers such as SBS, SBES, SES, and modified polyolefins can also be used. These may be used alone or in combination of two or more.

The acrylate copolymer (I), maleimide copolymer (II) and graft copolymer (III) may be produced by any polymerization method.
For example, a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, an emulsion-suspension polymerization method, an emulsion-bulk polymerization method, etc. May be. Emulsion polymerization is preferred for the graft copolymer (III) because the graft ratio can be easily controlled.

The copolymers (I), (II) and (II)
I) may be any of initiators, chain transfer agents and emulsifiers. Examples of the initiator include a thermal decomposition initiator such as potassium persulfate, and a redox such as Fe-reducing agent-organic peroxide. A system initiator and the like can be used.
Examples of the chain transfer agent include t-dodecyl mercaptan, n-
Dodecyl mercaptan, α-methylstyrene dimer,
Terpinolene or the like can be used. Examples of the emulsifier include fatty acid metal salt-based emulsifiers such as sodium oleate, sodium palmitate, and sodium rosinate, sodium dodecylbenzenesulfonate, sodium alkylsulfonate having 12 to 20 carbon atoms,
A sulfonic acid metal salt-based emulsifier such as sodium dioctyl sulfosuccinate can be used. These are all used alone or in combination of two or more.

In the thermoplastic resin composition of the present invention, commonly known antioxidants, heat stabilizers, UV absorbers, pigments, antistatic agents, lubricants, and the like can be used as needed. In particular, phenolic resins used in styrene resins,
Sulfur-based, phosphorus-based, hindered amine-based stabilizers, antioxidants, benzophenone-based, benzotriazole-based ultraviolet absorbers and organopolysiloxanes, aliphatic hydrocarbons, esters of higher fatty acids and higher alcohols, amides or bisamides of higher fatty acids In addition, internal lubricants and external lubricants such as modified products thereof, oligoamides, metal salts of higher fatty acids, and the like can be used to improve the performance of the composition of the present invention as a molding resin. These can be used alone or in combination of two or more.

The thermoplastic resin composition of the present invention may further comprise another styrene resin, for example, an acrylonitrile-styrene copolymer, an acrylonitrile-styrene-α-methylstyrene copolymer, an acrylonitrile-α-methylstyrene copolymer. , Acrylonitrile-methyl methacrylate-α-methylstyrene copolymer, styrene-maleimide copolymer, styrene-maleic anhydride copolymer,
One or more kinds of styrene-methyl methacrylate copolymers or the like can be mixed at 50% by weight or less, preferably at 40% by weight or less, to adjust to the desired performance.
Further, it is also possible to mix one or more of polycarbonate resin, polyvinyl chloride resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyamide resin and the like.

In the present invention, the thermoplastic resin composition comprising the acrylate copolymer (I), the maleimide copolymer (II), the graft copolymer (III), and another thermoplastic resin (IV) is Depending on the production method, for example, they can be produced by mixing them in the form of latex, slurry, solution, powder, pellets or the like, or by combining them. Acrylic ester copolymer (I) after polymerization
When polymer powders are recovered from latex of maleimide, maleimide copolymer (II), latex of graft copolymer (III), and latex of other thermoplastic resin (IV), the usual method is used, for example, chloride is added to latex. Adding alkaline earth metal salts such as calcium, magnesium chloride, magnesium sulfate, alkali metal salts such as sodium chloride and sodium sulfate, inorganic acids and organic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid After coagulating the latex in the above, it can be carried out by a method of dehydrating and drying. Also, a spray drying method can be used. A part of the used amount of the stabilizer may be added in the form of a dispersion to a latex or slurry of these resins.

The thermoplastic resin composition according to the present invention comprises an acrylic ester copolymer (I), a maleimide copolymer (II), a graft copolymer (III), and another thermoplastic resin (IV). The above-mentioned stabilizer, if necessary, a lubricant, a pigment and the like are blended with a powder or a pellet consisting of a mixture of two or more of these, and a known mixture such as a Banbury mixer, a roll mill, a single-screw extruder, or a twin-screw extruder is used. It can be kneaded with a melt kneader.

The molded article of the present invention is molded by the injection molding method using the above-mentioned thermoplastic resin composition. The injection molded body is H
From the viewpoint of the IC value and the surface cracking property at the time of impact, preferably, a rib having a thickness of 0.1 to 5 mm and a height of 3 to 50 mm is provided with a rib interval of 1 mm.
Average wall thickness of 2 to 50 mm with 2 or more continuous sections
A shape with a height of 5 to 5 mm and a maximum height of 3.5 to 55 mm is good. More preferably, an average wall thickness of 1.0 to 4.5 mm having a portion in which four or more ribs having a thickness of 0.3 to 4.5 mm and a height of 5 to 45 mm are connected at a rib interval of 5 to 45 mm and a maximum height of 5 ~ 50mm
And more preferably, an average thickness of 1.0 to 4.5 mm having a portion in which five or more ribs having a thickness of 0.5 to 4.0 mm and a height of 8 to 40 mm are continuously connected at a rib interval of 7 to 40 mm. The shape with a maximum height of 5 to 50 mm is good. The rib may be provided at any position on the molded product as long as the rib can maintain the above-described shape. It may be arranged horizontally, vertically, or obliquely to the longitudinal direction of the molded article. Horizontal ribs, vertical ribs, and oblique ribs can be combined. The thickness, height, and direction of each rib may be the same or may be changed. Specific examples of the injection molded body include pillar materials, door materials,
Interior / exterior resin products for automobiles such as instrument panel materials, center panel materials, grill guard materials, etc., seats for trains and airplanes and their peripheral members, toys and vehicles for babies and infants, and the like.

[0032]

EXAMPLES Hereinafter, the present invention will be described with reference to specific examples, but these examples do not limit the present invention. In the examples, "parts" indicates parts by weight, and "%" indicates% by weight. In the following description, abbreviations represent the following substances, respectively. BA: butyl acrylate 2EHA: 2-ethylhexyl acrylate TAC: triallyl cyanurate MMA: methyl methacrylate 2EHMA: 2-ethylhexyl methacrylate AN: acrylonitrile St: styrene tDM: t-dodecyl mercaptan CHP: cumene hydroperoxide PMI: N-phenylmaleimide αMSt: α-methylstyrene BMA: butyl methacrylate MAA: methacrylic acid Other thermoplastic resin (IV-a): AN / St / αMSt =
Copolymer of 25/10/60, reduced viscosity 0.58 dl / g Other thermoplastic resin (IV-b): AN / St = 28/7
2. Copolymer with reduced viscosity of 0.65 dl / g

Examples 1 to 6 and Comparative Examples 1 to 6 (1) Production of acrylate copolymer (I) Polymerization of acrylate copolymer (Ia) Stirrer, reflux condenser, nitrogen Introducer, monomer inlet, reactor equipped with a thermometer, 250 parts of pure water, 2.0 parts of sodium dioctyl sulfosuccinate, 0.5 parts of sodium formaldehyde sulfoxylate, 0.01 parts of sodium ethylenediaminetetraacetate, Ferrous sulfate 0.002
5 parts were charged. While stirring the reactor, 6
The temperature was raised to 5 ° C. After reaching 65 ° C., 64 parts of BA, A
N28 part, 2EHA5 part, St3 part, tDM0.5 part,
A mixture of 0.3 parts of CHP was continuously added dropwise over 7 hours.
Further, 0.5 parts of sodium dioctylsulfosuccinate was added at 1 hour of polymerization time and 0.5 parts at 3 hours. After completion of the dropwise addition, stirring was continued at 65 ° C. for 1 hour to terminate the polymerization,
An acrylate copolymer (Ia) was produced.
Table 1 shows the results. Production of Acrylic Ester Copolymer (I-b) In the same manner as for the acrylate ester copolymer (Ia), the monomers were prepared by mixing 57 parts of BA, 10 parts of BMA, 5 parts of MMA,
AN22 part, St6 part and tDM0.35 part, CHP
0.3 parts of the acrylate-based copolymer (I-
b) was prepared. Table 1 shows the results. Production of Acrylic Ester Copolymer (Ic) 30 parts of BA, 45 parts of AN, 25 parts of St, and tDM in the same manner as for acrylate copolymer (Ia).
As 0.5 part and 0.3 part of CHP, an acrylate copolymer (Ic) was produced. Table 1 shows the results. Production of Copolymer (Id) 93 parts of BA, 7 parts of AN, 0.35 part of tDM, and C in the same manner as for the acrylate-based copolymer (Ia).
As 0.3 parts of HP, an acrylate-based copolymer (Id) was produced. Table 1 shows the results.

[0034]

[Table 1]

(2) Production of Maleimide Copolymer (II) Production of Maleimide Copolymer (II-a) A reactor equipped with a stirrer, reflux condenser, nitrogen inlet, monomer inlet, and thermometer Then, 250 parts of pure water, 2 parts of sodium dioctyl sulfosuccinate, 0.5 part of sodium formaldehyde sulfoxylate, 0.01 part of sodium ethylenediaminetetraacetate, and 0.0025 part of ferrous sulfate were charged. 65 ° C. under a nitrogen stream while stirring the reactor
Temperature. After reaching 65 ° C., 13 parts of PMI, A
N25 parts, St37 parts, αMSt25 parts, tDM0.4
A mixture of 5 parts and 0.4 part of CHP was continuously added dropwise over 7 hours. Further, 0.5 parts of sodium dioctylsulfosuccinate was added at 1 hour of polymerization time and 0.5 parts at 3 hours. After completion of the dropwise addition, stirring was continued at 65 ° C. for 1 hour to terminate the polymerization, thereby producing a maleimide-based copolymer (II-a). Table 2 shows the results. Production of Maleimide Copolymer (II-b) In the same manner as for the maleimide copolymer (II-a), 30 parts of PMI, 17 parts of AN, 17 parts of St, 53 parts of t
A maleimide-based copolymer (II-b) was produced with 0.35 parts of DM and 0.3 parts of CHP. Table 2 shows the results.

[0036]

[Table 2]

(3) Production of rubber polymer (B) As the first step, unexpanded rubber polymer (B-1), (B-
2) was manufactured. Production of Rubber Polymer (B-1) 230 parts of pure water, 0.2 parts of potassium persulfate, t
0.15 parts of DM was charged. After the air in the reactor was removed by a vacuum pump, 0.6 part of sodium oleate, 2 parts of sodium rosinate and 100 parts of butadiene were charged. The temperature of the system was raised to 60 ° C. to initiate polymerization. Polymerization is 25
Finished in time. The polymerization conversion was 96%, and the particle size of the unexpanded rubber polymer (B-1) was 83 nm. Production of Rubber Polymer (B-2) 200 parts of pure water, 0.2 part of sodium palmitate, sodium formaldehyde sulfo were placed in a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, a monomer inlet, and a thermometer. 0.5 part of xylate, 0.01 part of sodium ethylenediaminetetraacetate, and 0.0025 part of ferrous sulfate were charged. The reactor was heated to 55 ° C. under a nitrogen stream while stirring. After reaching 55 ° C, 85 parts of BA, 10 parts of BMA,
A monomer mixture of 5 parts of 2EHA, 1.5 parts of TAC, and 0.3 parts of CHP was added dropwise over 7 hours. After 1 hour during the dropping of the monomer mixture for 7 hours, 0.3% of sodium palmitate was added.
, 0.5 part after 3 hours and 0.5 part after 5 hours. After completion of the dropwise addition, stirring was continued at 55 ° C. for 1 hour to terminate the polymerization. The polymerization conversion rate is 98%, and the unexpanded rubber polymer (B-
The particle size of 2) was 110 nm.

(4) Production of Latex Containing Acid Group (S) As the second step, the above unexpanded rubber polymer (B-1)
An acid group-containing latex (S) required for enlarging (B-2) was produced as follows. Production of acid group-containing latex (S-1) In a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, a monomer inlet, and a thermometer, 200 parts of pure water, 0.6 parts of sodium dioctylsulfosuccinate, and sodium 0.5 parts of formaldehyde sulfoxylate, 0.01 parts of sodium ethylenediaminetetraacetate, 0.002 of ferrous sulfate
5 parts were charged. The reactor was stirred under a stream of nitrogen for 7 hours.
The temperature was raised to 0 ° C. After reaching 70 ° C., 25 parts of BMA,
A monomer mixture of 5 parts of BA, 0.1 part of tDM and 0.15 part of CHP was added dropwise over 2 hours, and then 50 parts of BMA and 2E
HA 4 parts, MAA 16 parts, tDM 0.25 parts, CHP
0.15 parts was added dropwise over 4 hours.
For 1 hour to complete the polymerization and obtain an acid group-containing latex (S-1). Table 3 shows the results. Production of Acid Group-Containing Latex (S-2) In the same manner as for the acid group-containing latex (S-1), an acid group-containing latex (S-
2) was manufactured. Table 3 shows the results.

[0039]

[Table 3]

(5) Production of Rubber Polymer (A) As a third step, the unexpanded rubber polymers (B-1) and (B-2) produced in (3) and (4) were produced. Rubber polymers (A-1) and (A-2) were produced using acid group-containing latexes (S-1) and (S-2). Production of rubber polymer (A-1) 3.5 parts (solid content) of acid group-containing latex (S-1) was added to 100 parts (solid content) of latex of unexpanded rubber polymer (B-1) at 60 ° C. After the addition, stirring was continued for one hour to enlarge the mixture, thereby producing a rubber polymer (A-1). The particle size of the rubber polymer (A-1) was 420 nm.

Production of Rubber Polymer (A-2) 100 parts (solid content) of the latex of the unexpanded rubber polymer (B-2) and 2 parts (solid content) of an acid group-containing latex (S-2)
Was added at 60 ° C., and stirring was continued for 1 hour to enlarge the polymer, thereby producing a rubber polymer (A-2). Rubber polymer (A-
The particle size of 2) was 640 nm.

(6) Production of Graft Copolymer (III) Production of Graft Copolymer (III-a) In a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, a monomer inlet, and a thermometer, 280 parts of pure water, 60 parts of a rubber polymer (A-1) (solid content), 0.3 parts of sodium formaldehyde sulfoxylate, 0.01 parts of sodium ethylenediaminetetraacetate, and 0.0025 parts of ferrous sulfate were charged. . The reactor was heated to 60 ° C. under a nitrogen stream while stirring. After reaching 60 ° C., AN10 part, St10
, 20 parts of MMA and 0.3 parts of CHP were continuously added dropwise over 5 hours. After completion of the dropwise addition, stirring was continued at 60 ° C. for 2 hours to terminate the polymerization, and a graft polymer (III-a) was obtained. Table 4 shows the results. Production of Graft Copolymer (III-b) In the same manner as for the graft copolymer (III-a), 70 parts of the rubber polymer (A-2) was added to 8 parts of AN, 22 parts of St and 22 parts of CHP.
Polymerization was carried out at 0.3 part to produce a graft copolymer (III-b). Table 4 shows the results.

[0043]

[Table 4]

(7) Production of thermoplastic resin composition (A) Latex of acrylate copolymer (Ia) or (Ib) produced in (1) above, (2)
Maleimide copolymer (II-a), (II-
The latex of b) and the latex of the graft copolymers (III-a) to (III-b) produced in (6) were uniformly mixed at a predetermined ratio shown in Table 5, and a phenolic antioxidant was added. Thereafter, calcium chloride was added for coagulation. The solidified slurry was heat-treated, dehydrated and dried to obtain a powder of a resin composition of a mixture of (I), (II) and (III). Then, 1 part of ethylenebisstearylamide was mixed with the obtained resin composition, and uniformly blended for 10 minutes with a 20 L blender manufactured by Tabata Co., Ltd. Further, the mixture was melt-kneaded at a vent vacuum of 700 mmHg at 250 ° C. using a 44 m / m biaxial bend extruder manufactured by Nippon Steel Pipe Co., Ltd. to produce pellets of a thermoplastic resin composition (Examples 1 to 6).

(B) Acrylic ester copolymers (Ia), (Ib), (I-
c) The latex of the maleimide-based copolymer (II-a) produced in (2) was added to the latex of (Id)
After mixing at a ratio of (II) = 2/1 (solid content ratio) and adding a phenolic antioxidant, calcium chloride was added for coagulation. The coagulated slurry is heat-treated, dehydrated and dried, and (I)
(II) Powder (A) of the mixed resin composition was obtained. Separately, the graft copolymer at a ratio of a predetermined amount shown in Table 5
(III-a) Latex and maleimide copolymer (II-
The latex of a) was mixed, a phenolic antioxidant was added, and calcium chloride was added to coagulate. The solidified slurry was heat-treated, dehydrated and dried to obtain a powder (B) of the resin composition of the mixture of (I) and (II). The above two kinds of powders (A) and (B) were added at a ratio of a predetermined amount shown in Table 5 and 1 part of ethylenebisstearylamide was added to 100 parts of the resin powder. The mixture was uniformly blended at room temperature for 5 minutes in a 20L blender manufactured by Tokyo Electron Limited. Further, the mixture was melt-kneaded with a 40 m / ml l-axis bend extruder manufactured by Tabata Co., Ltd. at 250 ° C. at a degree of vent vacuum of 700 mmHg to produce pellets of a thermoplastic resin composition (Comparative Examples 1 to 6).

From the pellets of the thermoplastic resin composition obtained as described above, FAS15 manufactured by FANUC
Using an OB injection molding machine, three types of molded products (a),
(B) and (c) were molded at a cylinder temperature of 270 ° C.
1 and 2 show schematic diagrams of the molded body (a). The molded body (a) is a pillar cover for an automobile in which longitudinal ribs 2 and horizontal ribs 3 are arranged at equal intervals inside a molded body 1 having a substantially C-shaped cross section. The rib thickness is 1.0 mm (upper end). 4mm (root),
Rib height 27mm, horizontal rib spacing 30mm, body thickness 2.3
mm and the height of the main body is 29.3 mm. The molded body (b) has the same shape as the molded body (a), and has a rib thickness of 1.5 mm (upper end).
~ 2.0mm (root), rib height 16mm, horizontal rib spacing 40
mm, the thickness of the main body is 3.3 mm, and the height of the main body is 19.3 mm. The molded article (c) has the same shape as the molded article (a), with a rib thickness of 0.6 mm (upper end) to 0.9 mm (root), a rib height of 34 mm, a horizontal rib interval of 20 mm, and a wall thickness of the main body of 1. The height is 8 mm and the height of the main body is 35.8 mm. The obtained molded body (a),
Regarding (b) and (c), the phase structure and properties of the molded body were observed and measured by the following methods. The results are shown in Table 5.

[Phase Structure of Molded Product] A cross section of the center of the top surface of the molded product, including the surface portion, parallel to the resin flow direction and perpendicular to the surface was cut out and dyed with osmium tetroxide / ruthenium oxide. Stripes (A) (relatively white), islands (B) (relatively black when using butadiene rubber), and sea-like parts (C) (relatively gray) at a depth of 5 μm from the surface Images were taken and observed with a transmission electron microscope. The widths of 100 locations of the streak portion (A) were randomly measured from the photograph, and the average width of the streak portion (A) was calculated. Island (B)
The average particle size was calculated by an image analysis method using Luzex II manufactured by Nireco Co., Ltd. FIG. 3 is a transmission electron micrograph (magnification: 40,000 times) showing the phase structure of the molded article of Example 1.
FIG. 4 is a view for explaining a phase structure composed of streaks (A), islands (B), and seas (C) in the photograph, and is clearly shown in the photograph. This is a trace of what is being done.

[HIC value] The HIC value is the acceleration when a 4.5 kg hemisphere collides with a molded body at a speed of 24 km / hr.
The time change was measured and calculated [index]. The smaller the HIC value, the better. Moreover, the presence or absence of cracks on the top surface of the molded body after the test was evaluated by （(absent) and × (existent). [Appearance] The appearance was evaluated by visually observing the molded article by a five-point method, particularly for uneven color and flow marks. 5 points: Uneven color, no flow mark, 4 points: almost none, 3 points: slightly, 2 points: present, 1 point: remarkable. [Heat Deformation Resistance] The heat deformation resistance was measured by measuring the maximum amount of thermal deformation after placing the above-mentioned molded body at two points with a span of 24 cm and placing it in an atmosphere at 85 ° C. for 24 hours. The smaller the numerical value of the thermal deformation, the better.

From the results shown in Table 5, the injection molded articles of the present invention represented by Examples 1 to 6 have particularly low HIC values, no cracks, high heat deformation resistance, and excellent appearance. .

[0050]

[Table 5]

In Tables 1 to 4, Tg (glass transition temperature), reduced viscosity, particle size of the rubber polymer, and polymerization conversion were measured by the following methods.

[Calculation of Tg (Glass Transition Temperature)] The Tg of the acrylate copolymer (I) was calculated from the Tg of the homopolymer of each component (described in the “Polymer Handbook”) using the Fox equation. . [Measurement of Gel Content] Calcium chloride was added to the latex of the acrylate copolymer (I) to coagulate it. The resin powder obtained by heat treatment, dehydration and drying of the coagulated slurry was converted into a 2% methyl ethyl ketone solution,
The mixture was left for a while, filtered through a 100-mesh wire gauze, and the residue was dried and measured. (Filtration residue weight / original weight) x 1
Expressed as 00 (%).

[Measurement of Reduced Viscosity] Calcium chloride was added to the latex of the acrylate copolymer (I) or the maleimide copolymer (II) to coagulate it. The resin powder obtained by subjecting the coagulated slurry to heat treatment, dehydration and drying is added to a 0.1 wt.
The reduced viscosity was measured at 30 ° C. as a 3 g / dl N, N-dimethylformamide solution. (Graft rate of graft copolymer) Graft copolymer (I
Calcium chloride was added to the latex of II) for coagulation. The resin powder obtained by heat treating, dehydrating and drying the coagulated slurry was dissolved in methyl ethyl ketone and centrifuged to obtain a methyl ethyl ketone soluble component and an insoluble component. The graft ratio was specified from the ratio of the insoluble component to the soluble component.

[Particle Size of Rubber Polymer] The rubber polymer latex was measured using a Nicomp particle size analyzer manufactured by Pacific Science Corporation. [Conversion rate during polymerization] The conversion rate during polymerization was calculated from the solid content concentration.

[0055]

As described above, the injection molded article of the present invention
It has a low HIC value, has no surface cracks upon impact, and is excellent in heat-resistant deformation properties and appearance (surface properties).

[Brief description of the drawings]

FIG. 1 is a schematic top view of an injection molded body (a).

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a transmission electron micrograph (magnification: 40,000) showing the phase structure of the injection molded article of Example 1.

FIG. 4 is a diagram tracing the phase structure of FIG. 3;

[Explanation of symbols]

 1 body 2 vertical ribs 3 horizontal ribs

Claims (6)

[Claims] 1. An acrylic ester copolymer (I) 5
To 65 parts by weight, maleimide copolymer (II) 15 to 80
Parts by weight, 5 to 75 parts by weight of a graft copolymer (III), and 0 to 50 parts by weight of another thermoplastic resin (IV) [(I), (II), (III), (IV) 100 parts by weight in total] and a depth of 5 μm from the surface of the molded article
The phase structure observed with a transmission electron microscope in a cross section parallel to the resin flow direction at an average width of 0.0005 to 10 μm
m, having a streak portion (A), an island portion (B) having an average particle size of 0.005 to 2 μm, and a sea portion (C) other than the above (A) and (B). body. 2. An average wall thickness of 0.5 to 5 mm and a maximum height of two or more ribs having a thickness of 0.1 to 5 mm and a height of 3 to 50 mm, and two or more ribs connected at a rib interval of 1 to 50 mm. The injection molded article according to claim 1, which has a thickness of 5 to 55 mm. 3. An acrylic ester copolymer (I)
Is 40 to 85% by weight of an acrylate, 15 to 40% by weight of a vinyl cyanide compound, and 0 to 0 of an aromatic vinyl compound.
Tg of 2% obtained by polymerizing 45% by weight and 0 to 30% by weight of monomers copolymerizable therewith (total of 100% by weight).
It is a copolymer having a gel content of 0 ° C. or less and a gel content of 10% by weight or less.
(In N, N-dimethylformamide solution) 0.3-1.
The injection molded product according to claim 1 or 2, wherein the injection molded product has a flow rate of 2 dl / g. 4. The maleimide-based copolymer (II) comprises 10 to 40% by weight of a vinyl cyanide compound, 5 to 50% by weight of a maleimide-based compound, and 10 to 85% by weight of an aromatic vinyl compound.
And a copolymer obtained by polymerizing 0 to 30% by weight (100% by weight in total) of a monomer copolymerizable therewith and containing at least 49 mol% of an aromatic vinyl compound, The injection molded article according to any one of claims 1 to 3, wherein the reduced viscosity (30 ° C, in an N, N-dimethylformamide solution) is 0.3 to 1.2 dl / g. 5. The graft copolymer (III) is at least one selected from the group consisting of diene rubber polymers, olefin rubber polymers and acrylic rubber polymers having a volume average particle size of 50 to 1000 nm. Rubber polymer (A), 10 to 90% by weight of aromatic vinyl compound, 10 to 90% by weight of at least one selected from the group consisting of (meth) acrylate and vinyl cyanide compound, and copolymerizable with these And a graft portion (B) obtained by polymerizing a monomer mixture of 0 to 30% by weight (a total of 100% by weight) with a graft ratio of 10 to 80% by weight. The injection molded article according to any one of the above. 6. The rubber composition according to claim 5, wherein the content of the rubber polymer is 5 to 50 in the resin composition.
The injection molded product according to any one of claims 1 to 5, which is in terms of% by weight.