JP2019127510A - Resin molded article for vehicle - Google Patents

Abstract

To provide a resin molded article for a vehicle, comprising a resin composition excellent in fluidity, having high surface resistance, excellent in heat resistance, and excellent in surface appearance even when being wall-thinned/large-sized.SOLUTION: A resin molded article 10 for a vehicle comprises a thermoplastic resin composition which contains a copolymer (A) obtained by polymerizing vinyl monomer components (m1) containing a (meta) acrylic acid ester monomer, an N-substituted maleimide monomer, and an aromatic vinyl monomer. In the resin molded article 10 for a vehicle, a content of the (meta) acrylic acid ester monomer is 30-92 mass%, a content of the N-substituted maleimide monomer is 1-25 mass%, and a content of the aromatic vinyl monomer is 7-45 mass% to the total mass of the vinyl monomer components (m1).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin molded article for automobiles.

  Methacrylic acid ester resins are used in various fields such as automotive parts, building materials, home appliances, and lighting fixtures because of their excellent transparency and high surface hardness. Further, the methacrylic acid ester resin is also suitable as a material for a paint-less molded article because it is excellent in color development. For example, molded articles such as interior and exterior resin parts for automobiles are required to be usable without painting treatment on the surface from the viewpoint of manufacturing cost reduction, and methacrylic acid ester resin is used for interior and exterior resin parts for automobiles It is suitable as a material.

  As an interior / exterior resin part for motor vehicles using a methacrylic acid ester resin, for example, Patent Document 1 discloses a specific amount of a methacrylic acid ester monomer unit and a vinyl monomer unit such as methyl acrylate or ethyl methacrylate. A molded article obtained by molding a methacrylic resin composition is disclosed.

JP, 2016-6164, A

2. Description of the Related Art In recent years, in the automobile industry, the shape of automobile parts has become larger, and parts tend to be thinned in order to cope with cost reduction and weight reduction. Since large-sized molded articles are often produced by injection molding, resins are required to have excellent fluidity.
However, since the methacrylic resin composition described in Patent Document 1 is inferior in fluidity, it is not necessarily suitable for producing large-sized molded articles. Moreover, the molded article which shape | molded the methacrylic resin composition of patent document 1 had inadequate heat resistance.

  By the way, along with the enlargement of the shape of automobile parts, appearance defects such as silver streaks tend to occur easily at the time of molding. Therefore, the molded article is required to have a good appearance even if it is large.

  An object of the present invention is to provide a resin molded article for an automobile, which comprises a resin composition excellent in fluidity, has high surface hardness, is excellent in heat resistance, and is excellent in surface appearance even when it is thin and large.

The present invention includes the following aspects.
[1] A copolymer obtained by polymerizing a vinyl-based monomer component (m1) containing (meth) acrylic acid ester monomer, N-substituted maleimide monomer and aromatic vinyl monomer A resin molded article for automobiles comprising a thermoplastic resin composition containing (A),
The content of the (meth) acrylic acid ester monomer is 30 to 92% by mass with respect to the total mass of the vinyl monomer component (m1), and the content of the N-substituted maleimide monomer The resin molded article for motor vehicles whose is 1-25 mass%, and whose content of the said aromatic vinyl monomer is 7-45 mass%.
[2] The resin molding for automobiles according to [1], wherein a thickness t (mm) and a resin flow length L (mm) of the resin molding for automobiles satisfy the following formulas (1) and (2). Goods.
t <4.0 (1)
L / t> 200 (2)
[3] The thermoplastic resin composition further includes a graft copolymer (B) obtained by graft polymerization of a vinyl monomer component (m2) in the presence of a rubber-like polymer, [1] or The resin molded product for automobiles according to [2].

  The resin molded article for automobiles of the present invention comprises a resin composition having excellent fluidity, has high surface hardness, excellent heat resistance, and excellent surface appearance even when it is thin and large.

It is a perspective view which shows an example of the resin molded product for motor vehicles of this invention.

"Automotive resin molded products"
Hereinafter, an embodiment of an automotive resin molded product of the present invention will be described.
In the present invention, "(meth) acrylic acid" is a generic term for acrylic acid and methacrylic acid.
Moreover, in this specification, "mass average molecular weight" and "number average molecular weight" are the mass average molecular weight or number average molecular weight of polystyrene conversion measured by gel permeation chromatography (GPC). The “volume average particle diameter” is a value calculated from the particle diameter distribution obtained by measuring a volume-based particle diameter distribution using a laser diffraction, scattering type particle size distribution measuring device.
Moreover, in this specification, the impact resistance by a falling ball test is also called "surface impact resistance" in particular.

The automotive resin molded product of the present invention is obtained by molding the following thermoplastic resin composition.
For example, as shown in FIG. 1, when the thickness of the resin molded article for automobile 10 is t (mm) and the resin flow length is L (mm), for example, as shown in FIG. It is preferable to satisfy 1) and formula (2).
t <4.0 (1)
L / t> 200 (2)

The thickness t of the resin molded product for automobiles means that the resin molded product for automobiles is cut in a direction perpendicular to the injection direction of the thermoplastic resin composition when the automobile resin molded product is manufactured by injection molding, that is, the flow direction. It is the thickness of the thinnest portion in the cutting direction on the cut surface when cut.
The smaller the value of thickness t, the thinner the resin molded product for automobiles. The lower limit value of the thickness t is not particularly limited, but the thickness t is more preferably 1 mm or more from the viewpoint of maintaining the strength of the resin molded article for an automobile favorably.

The resin flow length L of the resin molded product for automobiles is from the gate supplying the thermoplastic resin composition to the flow end of the farthest thermoplastic resin composition when manufacturing the resin molded product for automobiles by injection molding. The flow distance of the thermoplastic resin composition of In other words, it is the length in the injection direction of the resin molded article for automobiles.
When a plurality of gates are used, the longest distance among them is taken as the resin flow length L.

  The fact that the thickness t and the resin flow length L satisfy the above formulas (1) and (2) means that the resin molded article for automobiles is large and thin, and in particular, the value of L / t The larger the is, the larger the resin molded product for automobiles. The upper limit value of L / t is not particularly limited, and is appropriately determined according to the application of the resin molded article for automobiles.

<Thermoplastic resin composition>
The thermoplastic resin composition which comprises the resin molded product for motor vehicles contains the copolymer (A) shown below. Moreover, the thermoplastic resin composition may contain the graft copolymer (B) shown below.

(Copolymer (A))
The copolymer (A) is obtained by polymerizing a vinyl-based monomer component (m1) containing a (meth) acrylic acid ester monomer, an N-substituted maleimide monomer, and an aromatic vinyl monomer. It is obtained. That is, the copolymer (A) is a polymer of at least a (meth) acrylic acid ester monomer, an N-substituted maleimide monomer, and an aromatic vinyl monomer. A body unit, an N-substituted maleimide monomer unit, and an aromatic vinyl monomer unit.
The vinyl monomer component (m1) is a single amount other than the (meth) acrylic acid ester monomer, the N-substituted maleimide monomer, and the aromatic vinyl monomer depending on the physical properties required for the molded product. (Hereinafter also referred to as “other monomers”).

  In the copolymer (A), it is not always necessary to specify how the (meth) acrylic acid ester monomer, the N-substituted maleimide monomer and the aromatic vinyl monomer are polymerized. It's not easy. That is, there are circumstances (impossible / unpractical circumstances) in which the copolymer (A) cannot be directly identified by its structure or characteristics, or is almost impractical. Therefore, in the present invention, the copolymer (A) is “a vinyl monomer component containing a (meth) acrylic acid ester monomer, an N-substituted maleimide monomer, and an aromatic vinyl monomer. It is more appropriate to define “(m1) obtained by polymerizing”.

[(Meth) acrylic acid ester monomer]
Examples of (meth) acrylate monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, and t-butyl acrylate. Acrylics such as amyl acrylate, isoamyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, stearyl acrylate, cyclohexyl acrylate, pentyl acrylate, phenyl acrylate, benzyl acrylate, etc. Acid ester; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, Methacrylic acid octyl, decyl methacrylate, 2-ethylhexyl, methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, and methacrylic acid esters of phenyl methacrylate, and the like. Among these, methyl acrylate, methyl methacrylate and ethyl methacrylate are preferable, and methyl methacrylate and ethyl methacrylate are more preferable, from the viewpoint of further enhancing the surface hardness and color developability of the resin molded article for automobiles.
These (meth) acrylic acid ester monomers may be used alone or in combination of two or more.

  Content of a (meth) acrylic acid ester monomer is 30-92 mass% with respect to the total mass of a vinyl-type monomer component (m1), 40-84 mass% is preferable, and 50-72 mass. % Is more preferable. If the content of the (meth) acrylic acid ester monomer is equal to or more than the above lower limit value, the surface hardness of the automobile resin molded product is increased. When the content of the (meth) acrylic acid ester monomer is equal to or less than the above upper limit value, a monomer other than the (meth) acrylic acid ester monomer is sufficiently blended in the vinyl monomer component (m1) Since it can do, the fluidity of the thermoplastic resin composition and the heat resistance of the automotive resin molded article can be maintained well.

[N-substituted maleimide monomer]
As the N-substituted maleimide monomer, for example, N-methyl maleimide, N-ethyl maleimide, N-n-propyl maleimide, N-i-propyl maleimide, N-n-butyl maleimide, N-i-butyl maleimide, N N-alkyl maleimides such as tert-butyl maleimide; N-cycloalkyl maleimides such as N-cyclohexyl maleimide; N-phenyl maleimide, N- (2-methylphenyl) maleimide, N- (4-hydroxyphenyl) maleimide, N -N-aryl maleimide such as chlorophenyl maleimide; N-aralkyl maleimide and the like. Among these, N-arylmaleimide is preferable and N-phenylmaleimide is more preferable from the viewpoint of further improving the heat resistance of the resin molded article for automobiles and improving the impact resistance.
One of these N-substituted maleimide monomers may be used alone, or two or more thereof may be used in combination.

  The content of the N-substituted maleimide monomer is 1 to 25% by mass, preferably 1 to 23% by mass, and 3 to 15% by mass with respect to the total mass of the vinyl monomer component (m1). More preferable. When the content of the N-substituted maleimide monomer is equal to or more than the above lower limit value, the heat resistance of the automobile resin molded article is improved. If the content of the N-substituted maleimide monomer is equal to or less than the above upper limit value, the fluidity of the thermoplastic resin composition can be favorably maintained.

[Aromatic vinyl monomer]
Examples of the aromatic vinyl monomer include styrene, α-methyl styrene, o-, m- or p-methyl styrene, vinyl xylene, pt-butyl styrene, and ethyl styrene. Among these, styrene and α-methylstyrene are preferable from the viewpoints of further improving the flowability of the thermoplastic resin composition and improving the color developability and impact resistance of the resin molded article for automobiles.
These aromatic vinyl monomers may be used alone or in combination of two or more.

  The content of the aromatic vinyl monomer is 7 to 45% by mass, preferably 15 to 45% by mass, and more preferably 25 to 45% by mass, with respect to the total mass of the vinyl-based monomer component (m1). preferable. When the content of the aromatic vinyl monomer is equal to or more than the above lower limit value, the flowability of the thermoplastic resin composition is improved. If the content of the aromatic vinyl monomer is not more than the above upper limit, appearance defects such as silver streaks are less likely to occur, and a resin molded article for an automobile having excellent surface appearance can be obtained even if it is thin and large. In addition, the surface hardness and color developability of the automotive resin molded product can be maintained well.

[Other monomer]
Other monomers are not particularly limited as long as they can be copolymerized with (meth) acrylic acid ester monomers, N-substituted maleimide monomers and aromatic vinyl monomers, and examples thereof include acrylonitrile and methacrylonitrile. And vinyl cyanide monomers such as
One of these other monomers may be used alone, or two or more thereof may be used in combination.

  10 mass% or less is preferable with respect to the total mass of a vinyl-type monomer component (m1), and, as for content of another monomer, 5 mass% or less is more preferable. If the content of the other monomer is less than or equal to the above upper limit value, the effect of the present invention is easily exhibited.

[Method for producing copolymer (A)]
The copolymer (A) is produced, for example, by a known method such as bulk polymerization, solution polymerization, bulk suspension polymerization, suspension polymerization, emulsion polymerization, miniemulsion polymerization and the like. Among these, emulsion polymerization and miniemulsion polymerization are preferable because the particle diameter of the polymer (A) can be easily controlled.

  As a method for producing the copolymer (A) by the emulsion polymerization method, a method of adding a radical polymerization initiator and a vinyl monomer component (m1) to an aqueous solvent and copolymerizing in the presence of an emulsifier can be mentioned. . The addition method of the radical initiator and the vinyl-based monomer component (m1) may be any of batch, division and continuous.

As an emulsifier used for the emulsion polymerization method, an anionic surfactant, nonionic surfactant, an amphoteric surfactant etc. are mentioned, for example.
More specifically, as the emulsifier, higher alcohol sulfates, alkylbenzene sulfonates, fatty acid sulfonates, phosphates (for example, monoglyceride ammonium phosphate), fatty acid salts (for example, dipotassium alkenyl succinate), Anionic surfactants such as amino acid derivative salts; Nonionic surfactants such as ordinary polyethylene glycol alkyl ester type, alkyl ether type, alkyl phenyl ether type; carboxylate, sulfate ester salt, sulfonate in the anion part And amphoteric surfactants having a phosphate ester salt and the like and having an amine salt, a quaternary ammonium salt and the like in the cation portion.
One of these emulsifying agents may be used alone, or two or more thereof may be used in combination.

  10 mass parts or less are preferable with respect to 100 mass parts of vinyl-type monomer components (m1), and, as for the addition amount of an emulsifier, 0.01-10 mass parts is more preferable.

Known radical polymerization initiators used in the emulsion polymerization method can be used, for example, azo polymerization initiators, photopolymerization initiators, inorganic peroxides, organic peroxides, organic peroxides, transition metals, and reducing agents. And redox based initiators in combination with each other. Among these, an azo polymerization initiator capable of initiating polymerization by heating, an inorganic peroxide, an organic peroxide, and a redox initiator are preferable.
One of these radical initiators may be used alone, or two or more thereof may be used in combination.

  The addition amount of the radical polymerization initiator is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and further preferably 0.001 to 3 parts by mass with respect to 100 parts by mass of the vinyl monomer component (m1).

You may add a chain transfer agent as needed at the time of manufacture of a copolymer (A).
Examples of chain transfer agents include mercaptans such as octyl mercaptan, n- or t-dodecyl mercaptan, n-hexadecyl mercaptan, n- or t-tetradecyl mercaptan; allylsulfonic acid, methallylsulfonic acid, and sodium salts thereof. An allyl compound; α-methylstyrene dimer and the like. Among these, mercaptans are preferable because the molecular weight can be easily adjusted.
One of these chain transfer agents may be used alone, or two or more thereof may be used in combination.

The method for adding the chain transfer agent may be any of batch, split, and continuous.
2 mass parts or less are preferable with respect to 100 mass parts of vinyl-type monomer components (m1), and, as for the addition amount of a chain transfer agent, 0.01-2 mass parts is more preferable.

The copolymer (A) obtained by the emulsion polymerization method is usually in a latex state.
As a method of recovering the copolymer (A) from the latex of the copolymer (A), for example, a slurry of the copolymer (A) is introduced into hot water in which the coagulant is dissolved. A wet method in which the copolymer (A) is coagulated in a heated atmosphere, and a spray dry method in which the copolymer (A) is recovered semi-directly by spraying the latex of the copolymer (A) in a heated atmosphere.

[Physical Properties of Copolymer (A)]
The mass average molecular weight of the copolymer (A) is preferably 10,000 to 300,000, more preferably 50,000 to 150,000. When the weight average molecular weight of the copolymer (A) is not less than the above lower limit, impact resistance (surface impact resistance) by a falling ball test of an automotive resin molded product can be improved. If the mass average molecular weight of the copolymer (A) is less than or equal to the above upper limit value, the flowability of the thermoplastic resin composition is further improved.

  1.0-5.0 are preferable and, as for the molecular weight distribution (mass average molecular weight / number average molecular weight) of a copolymer (A), 1.5-3.0 are more preferable. When the molecular weight distribution of the copolymer (A) is equal to or more than the above lower limit value, the impact resistance of the resin molded article for automobiles is improved. If the molecular weight distribution of the copolymer (A) is not more than the above upper limit value, the flowability of the thermoplastic resin composition is further improved. In addition, the color developability of the resin molded product for automobiles is improved.

100-160 degreeC is preferable and, as for the glass transition temperature of a copolymer (A), 105-145 degreeC is more preferable. If the glass transition temperature of a copolymer (A) is more than the said lower limit, the heat resistance of the resin molded product for motor vehicles will improve more. If the glass transition temperature of the copolymer (A) is less than or equal to the above upper limit, the flowability of the thermoplastic resin composition is further improved.
The glass transition temperature of the copolymer (A) is a value determined by differential scanning calorimetry (DSC). Specifically, the temperature was raised from 35 ° C. to 250 ° C. at 10 ° C./min in a nitrogen atmosphere. It is a glass transition temperature observed when it cools to 35 degreeC and heats up to 250 degreeC again after that.

(Graft copolymer (B))
The graft copolymer (B) is obtained by graft polymerization of a vinyl monomer component (m2) in the presence of a rubbery polymer. That is, the graft copolymer (B) includes a rubber-like polymer (b1) portion and a polymer (b2) portion obtained by polymerizing the vinyl monomer component (m2).

  In the graft copolymer (B), it is difficult to specify how the vinyl monomer component (m2) is polymerized in the rubber-like polymer (b1). For example, the polymer (b2) includes those bonded to the rubber-like polymer (b1) and those not bonded to the rubber-like polymer (b1). Moreover, it is also difficult to specify the molecular weight of the polymer (b2) bonded to the rubbery polymer (b1), the ratio of the constituent units, and the like. That is, there is a situation (impossible / unpractical situation) that the graft polymer (B) cannot be directly specified by its structure or characteristics or is almost impractical. Therefore, in the present invention, it is more appropriate to define the graft polymer (B) as “obtained by graft polymerization of a vinyl monomer component (m2) on a rubbery polymer”.

[Rubber-like polymer]
Examples of the rubber-like polymer constituting the graft copolymer (B) include butadiene-based rubber-like polymers such as polybutadiene, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, and acrylate / butadiene copolymer. Conjugated diene rubbery polymers such as isoprene, chloroprene and styrene / isoprene copolymers; acrylic rubbery polymers such as butyl polyacrylate; olefin rubbery polymers such as ethylene / propylene copolymers; poly Examples thereof include silicone rubber-like polymers such as organosiloxane; natural rubber, butyl rubber, urethane rubber, chlorinated polyethylene, epichlorohydrin rubber, fluororubber, polysulfide rubber and the like. The rubbery polymer may have a composite rubber structure or a core-shell structure. Among these, a butadiene rubber, an acrylic rubber, or a composite rubber-like polymer thereof is preferable from the viewpoint of a good balance between the color tone and impact resistance of an automotive resin molded product.
One of these rubbery polymers may be used alone, or two or more thereof may be used in combination.

The rubbery polymer preferably has a gel content of 40 to 99% by mass, more preferably 50 to 99% by mass, still more preferably 60 to 95% by mass, and 70 to 85% by mass. Is particularly preferred. If the gel content of the rubbery polymer is within the above range, the mechanical properties, particularly the impact resistance, of the resin molded article for an automobile will be improved.
Specifically, the gel content of the rubber-like polymer can be measured as follows. That is, the weighed rubbery polymer is dissolved in an appropriate solvent at room temperature (23 ° C.) for 20 hours according to the type of rubbery polymer to form a solution. The solution is filtered through a 100 mesh wire mesh, the insoluble matter remaining on the wire mesh is recovered, dried at 60 ° C. for 24 hours, and then weighed. From the following formula (i), the ratio of the insoluble matter to the rubbery polymer initially weighed is determined, and this is taken as the gel content (unit: mass%) of the rubbery polymer.
Gel content = {(mass of insoluble matter after drying) × (mass of rubbery polymer before dissolving in solvent)} × 100 (i)

  As a solvent used for dissolving the rubbery polymer, for example, it is preferable to use toluene when the rubbery polymer is polybutadiene, and use acetone when the rubbery polymer is butyl polyacrylate.

  The rubbery polymer is typically granular. 0.1-1 micrometer is preferable and, as for the volume average particle diameter of a rubber-like polymer, 0.2-0.5 micrometer is more preferable. When the volume average particle diameter of the rubbery polymer is not less than the above lower limit value, the impact resistance of the resin molded article for automobile is improved, and when it is not more than the above upper limit value, the color developability of the resin molded article for automobile is improved.

[Vinyl monomer component (m2)]
As a vinyl-based monomer contained in the vinyl-based monomer component (m2), aromatic vinyl monomer, vinyl cyanide monomer, (meth) acrylate monomer, N-substituted maleimide monomer amount Body etc. are mentioned.
As the aromatic vinyl monomer, (meth) acrylate monomer, vinyl cyanide monomer and N-substituted maleimide monomer, the aromatic vinyl exemplified above in the description of the copolymer (A) Monomers, vinyl cyanide monomers, (meth) acrylic acid ester monomers, and N-substituted maleimide monomers may be mentioned, respectively.

As the vinyl monomer forming the graft copolymer (B), an aromatic vinyl monomer and a vinyl cyanide monomer are used from the viewpoint of improving mechanical properties and solvent resistance of resin molded products for automobiles. It is preferable to use in combination with
The ratio of each monomer in the mixture of the aromatic vinyl monomer and the vinyl cyanide monomer is such that when the total of the aromatic vinyl monomer and the vinyl cyanide monomer is 100% by mass, It is preferable that it is 40-90 mass% of a group vinyl-type monomer, and is 10-60 mass% of a vinyl cyanide-type monomer. More preferably, when the total of the aromatic vinyl monomer and the vinyl cyanide monomer is 100% by mass, the aromatic vinyl monomer is 45 to 85% by mass, and the vinyl cyanide single monomer The body is more preferably 15 to 55% by mass, the aromatic vinyl monomer is 50 to 80% by mass, and the vinyl cyanide monomer is further preferably 20 to 50% by mass. If the proportion of each monomer is within the above range, the impact resistance of the resin molded article for automobiles is further improved.
As a combination of an aromatic vinyl monomer and a vinyl cyanide monomer, a combination of styrene and acrylonitrile is preferable.

[Production method of graft copolymer (B)]
The graft copolymer (B) is obtained by polymerizing the vinyl monomer component (m2) in the presence of a rubbery polymer.
As a polymerization method, an emulsion polymerization method is preferable in that it can be controlled so that the reaction proceeds stably. Specifically, a method in which a vinyl-based monomer component (m2) is collectively charged into a latex of a rubber-like polymer and then polymerized; one of a vinyl-based monomer component (m2) in a latex of a rubber-like polymer And a method of polymerizing at any time while dropping the entire amount of the vinyl monomer component (m2) into the latex of the rubber-like polymer, and the like. The polymerization of the vinyl-based monomer component (m2) may be carried out in one stage or in two or more stages. When carrying out by dividing into two or more stages, it is also possible to carry out by changing the kind and composition ratio of the vinyl-based monomer component (m2) in each stage.

Emulsion polymerization is usually performed using a radical polymerization initiator and an emulsifier. For example, a vinyl monomer component (m2) is added to a latex of a rubbery polymer containing a rubber polymer, water and an emulsifier, and the vinyl monomer component (m2) is added in the presence of a radical polymerization initiator Radically polymerize.
When radical polymerization is performed, various known chain transfer agents may be added to control the molecular weight and grafting ratio of the resulting graft copolymer (B).
Examples of the emulsifier, the radical polymerization initiator, and the chain transfer agent include the emulsifier, the radical polymerization initiator, and the chain transfer agent exemplified above in the description of the method for producing the copolymer (A).
Examples of the conditions for radical polymerization include polymerization conditions at 50 to 100 ° C. for 1 to 10 hours.

  The mass ratio between the rubber-like polymer and the vinyl monomer component (m2) is such that the rubber-like polymer is 10 to 80% by mass and the vinyl monomer component (m2) is 20 to 90% by mass. More preferably, the rubber-like polymer is 30 to 70% by mass and the vinyl monomer component (m2) is 30 to 70% by mass (however, the rubber-like polymer and the vinyl monomer component (m2) ) Is 100% by mass.)

The graft copolymer (B) obtained by the emulsion polymerization method is usually in a latex state.
Examples of the method for recovering the graft copolymer (B) from the latex of the graft copolymer (B) include the recovery methods exemplified above in the description of the copolymer (A).

[Physical properties of graft copolymer (B)]
The graft ratio of the graft polymer (B) is preferably 40 to 150%, more preferably 50 to 120%, and more preferably 60 to 100%, from the viewpoint of the balance between impact resistance and color development of the resin molded product for automobiles. More preferable.
Specifically, the graft ratio of the graft polymer (B) can be measured as follows. That is, the graft polymer (B) is added to acetone, heated and refluxed at 65 to 70 ° C. for 3 hours, and the obtained suspension acetone solution is centrifuged at 14000 rpm to separate into acetone dissolved matter and acetone insoluble matter Do. Next, the acetone insoluble matter is vacuum dried, the mass of the acetone insoluble matter after drying is measured, and the grafting ratio of the graft polymer (B) is determined from the following formula (ii). Here, P in the formula (ii) is the mass (g) of the acetone insoluble matter after drying, and Q is the mass (g) of the rubber-like polymer used for the production of the graft polymer (B) .
Graft ratio (%) = {(P−Q) / Q} × 100 (ii)

(Optional ingredient)
If the thermoplastic resin composition is within the range not impairing the effects of the present invention, resins (other resins) other than the copolymer (A) and the graft copolymer (B) and various additions may be added as necessary. An agent may be included as an optional component.
Examples of other resins include polyamide resin, polyvinyl chloride resin, polyethylene terephthalate resin, polyphenylene ether resin, polyethylene naphthalate resin, polypropylene terephthalate resin, polyethylene resin, polypropylene resin, polyphenylene sulfide resin, polyacetal resin, polyimide resin, and phenol resin. And melamine resins, silicone resins, unsaturated polyester resins, epoxy resins and the like.
One of these other resins may be used alone, or two or more thereof may be used in combination.

Examples of additives include antioxidants, light stabilizers, etc., plasticizers, mold release agents, dyes, pigments, antistatic agents, flame retardants, inorganic fillers, metal powders and the like.
The thermoplastic resin composition may optionally contain a lubricant, but when the thermoplastic resin composition contains a lubricant, the lubricant may bleed out on the surface of the resin molded article for automobiles. In the case of the resin molded article for automobiles of the present invention, since the surface hardness is high, it is not necessary to increase the amount of the lubricant. Therefore, it is possible to suppress the appearance defect caused by bleeding out of the lubricant. From the viewpoint of easily maintaining a good surface appearance, the content of the lubricant is preferably 10% by mass or less, more preferably 5% by mass or less, and substantially no lubricant, relative to the total mass of the thermoplastic resin composition. Is preferred. Here, "substantially free" means that the content relative to the total mass of the thermoplastic resin composition is less than 0.01% by mass.

(Content of each component)
The content of each component contained in the thermoplastic resin composition is as follows.
When a thermoplastic resin composition consists only of a copolymer (A), content of a copolymer (A) is 100 mass% with respect to the gross mass of a thermoplastic resin composition.

When a thermoplastic resin composition contains components other than a copolymer (A), 50-90 mass% is preferable with respect to the total mass of a thermoplastic resin composition, and content of a copolymer (A) is 60. -80 mass% is more preferable. If content of a copolymer (A) is in the said range, the fluidity | liquidity of a thermoplastic resin composition can be maintained favorable. In addition, resin molded articles for automobiles having high surface hardness, excellent in heat resistance, and excellent in surface appearance even when made thin and large are easily obtained.
10-50 mass% is preferable with respect to the total mass of a thermoplastic resin composition, and, as for content of a graft copolymer (B), 20-40 mass% is more preferable. If the content of the copolymer (B) is within the above range, the impact resistance of the resin molded article for an automobile can be enhanced without interfering with the effects of the present invention.
20 mass% or less is preferable with respect to the total mass of a thermoplastic resin composition, and, as for content of an arbitrary component, 10 mass% or less is more preferable.

(Method of producing thermoplastic resin composition)
The thermoplastic resin composition is produced by mixing and kneading the copolymer (A) and the graft copolymer (B) and optional components used as needed.
The method of mixing and kneading the components contained in the thermoplastic resin composition is not particularly limited, and any of general mixing and kneading methods can be adopted. For example, a shaft extruder, a twin screw extruder, Banbury Examples thereof include a method of kneading with a mixer, a kneading roll or the like, then cutting with a pelletizer or the like and pelletizing.
The production of the thermoplastic resin composition may be carried out either batchwise or continuously. In addition, the order of mixing the respective components is not particularly limited as long as all the components are sufficiently uniformly mixed.

<Manufacturing method of resin molded products for automobiles>
The resin molded product for automobiles can be manufactured by molding the above-described thermoplastic resin composition.
As a molding method, a known molding method can be used, and examples thereof include an injection molding method, a press molding method, an extrusion molding method, a vacuum molding method, a blow molding method and the like. In particular, the resin molded product for automobiles is a large-sized molded product, specifically, the thickness t (mm) and the resin flow length L (mm) of the resin molded product for automobiles are the above formulas (1) and (2) When satisfying the above, an injection molding method is preferable as the molding method.

<Function effect>
The automotive resin molded article of the present invention described above is composed of the thermoplastic resin composition having excellent fluidity, including the specific copolymer (A) described above, and has high surface hardness and excellent heat resistance. Even if it is thin and large, the surface appearance is excellent. In particular, when the weight average molecular weight of the copolymer (A) is 10,000 or more, the surface impact resistance is also excellent. In addition, when the thermoplastic resin composition further contains the graft copolymer (B), the impact resistance is further improved.

<Use>
The resin molded product for automobiles of the present invention includes a roof garnish, a spoiler, a side panel, a side molding, a fender panel, a pillar guard, a pillar garnish, a door mirror housing, a front grill, a fog lamp cover, a bumper, and other exterior resin parts; a meter panel, It is suitably used for interior resin parts such as display parts, window switch panels, indicator panels and the like. The resin molded article for automobiles of the present invention is also suitable for various interior and exterior resin parts used without painting.

Hereinafter, an Example is shown concretely. However, the present invention is not limited to these examples.
"%" Described below means "mass%", and "part" means "mass part".
Various measurement / evaluation methods and components in the following examples are as follows.

"Measurement and evaluation"
(1) Measurement of mass average molecular weight and number average molecular weight The mass average molecular weight (Mw) and number average molecular weight in the copolymer (A) using a gel permeation chromatography apparatus (GPC apparatus) manufactured by Tosoh Corporation (Mn) was measured. In molecular weight measurement, a polymer sample was dissolved using tetrahydrofuran (THF) as a solvent, and the polymer sample was introduced into a GPC apparatus. Using a calibration curve obtained in advance with standard polystyrene having a known molecular weight, the molecular weight in terms of polystyrene of the polymer sample was measured, and the mass average molecular weight or number average molecular weight was determined.

(2) Measurement of glass transition temperature Using differential scanning calorimetry (DSC), copolymer (A) was heated from 35 ° C to 250 ° C at 10 ° C / min in a nitrogen atmosphere, and then cooled to 35 ° C. Then, the glass transition temperature observed when the temperature was raised again to 250 ° C. was obtained.

(3) Measuring method of gel content The weighed rubber-like polymer is dissolved in acetone at room temperature (23 ° C) for 20 hours to obtain a solution, and the obtained solution is filtered through a 100-mesh wire mesh. The remaining insoluble matter was collected, dried at 60 ° C. for 24 hours, and weighed. From the following formula (i), the proportion of the insoluble matter to the rubbery polymer initially weighed was determined, and this was taken as the gel content (unit: mass%) of the rubbery polymer.
Gel content = {(mass of insoluble matter after drying) × (mass of rubbery polymer before dissolving in solvent)} × 100 (i)

(4) Method of Measuring Volume Average Particle Size For a rubbery polymer, using Microtrac (“Nanotrac 150” manufactured by Nikkiso Co., Ltd.), using pure water as a measurement solvent, measure the volume average particle size (MV) did.

(5) Method of Measuring Graft Ratio The graft polymer (B) was washed with methanol, added to acetone, and heated under reflux at 65 ° C. for 3 hours. The resulting suspended acetone solution was centrifuged at 14000 rpm to separate into an acetone-dissolved fraction and an acetone-insoluble fraction. Subsequently, the acetone insoluble matter was vacuum dried, the mass of the acetone insoluble matter after drying was measured, and the graft ratio of the graft polymer (B) was determined from the following formula (ii). In the formula (ii), P is the mass (g) of acetone insoluble matter after drying, and Q is the mass (g) of the rubber-like polymer used for the production of the graft polymer (C). .
Graft rate (%) = {(PQ) / Q} × 100 (ii)

(6) Evaluation of fluidity 1: Measurement of melt volume rate (MVR) The MVR of the thermoplastic resin composition at 220 ° C. was measured under a load of 98 N (10 kg) in accordance with ISO 1133: 1997. In addition, MVR becomes a standard of the fluidity of a thermoplastic resin composition, and it means that it is excellent in fluidity, so that a numerical value is high.

(7) Evaluation of flowability 2: Measurement of spiral flow length Cylinder temperature 280 ° C., mold temperature 60 ° C., injection pressure 100 MPa, injection time 2 seconds, pressure holding time 8 seconds, cooling time 15 seconds, molten resin measurement value 20 Using a 85 ton injection molding machine ("J85AD-110H" manufactured by Japan Steel Works, Ltd.), pellets of the thermoplastic resin composition are used on a condition of -35 mm and a molding cycle of 26.5 seconds, and the cross-sectional thickness is 2 mm and width 15 mm. A spiral flow mold with a gate at the center and a shape in which the resin flows spirally toward the outside. It is.
The spiral flow length (mm) of the obtained molded product (280 ° C. spiral flow molded product) was measured. The longer the spiral flow length, the better the fluidity (spiral flow).

(8) Evaluation of flowability 3: Measurement of spiral flow length A molded product obtained by injection molding pellets of a thermoplastic resin composition in the same manner as evaluation 2 except that the cylinder temperature was changed to 290 ° C. Spiral flow length (mm) of the spiral flow molded product was measured.

(9) Evaluation of surface appearance 1: Evaluation of appearance of spiral flow molded product Occurrence of silver streaks by visually observing the surface appearance of the 280 ° C. spiral flow molded product obtained in the above (7) Evaluation of fluidity 2 The presence or absence was confirmed, and the following evaluation criteria evaluated.
○: Silver streak does not occur.
Fair: 1 to 4 silver streaks are generated.
X: 5 or more silver streaks have occurred.

(10) Evaluation of surface appearance 2: Evaluation of appearance of spiral flow molded article Presence or absence of silver streak by visually observing the surface appearance of the 290 ° C. spiral flow molded article obtained in the above (8) Evaluation of fluidity 3 And evaluated according to the following evaluation criteria.
○: Silver streak does not occur.
Fair: 1 to 4 silver streaks are generated.
X: 5 or more silver streaks have occurred.

(11) Evaluation of color development L ^{* of} a molded product was measured using a colorimeter ("CM-508D" manufactured by Konica Minolta Japan Co., Ltd.). The smaller the value of L ^*, the deeper (darker) the blackness of the molded article and the better the color developability.

(12) Measurement of pencil hardness According to JIS K5600, the pencil hardness of a molded article was measured at a load of 750 g. The harder the pencil hardness, the better the scratch resistance when scratched with a hard thing, which means that the surface hardness is higher.

(13) Evaluation of impact resistance 1: Measurement of Charpy impact strength Charpy of a molded article (type B1, with notch: shape A single notch) at a test temperature of 23 ° C. in accordance with ISO 179-1: 2013 edition. Impact strength (direction of impact: edgewise) was measured. The higher the Charpy impact strength, the better the impact resistance.

(14) Evaluation of impact resistance 2: Measurement of falling ball impact height With respect to a molded product whose temperature was adjusted to -30 ° C, the falling ball impact height was measured as follows.
A steel ball with a weight of 500 g was dropped from the height of 10 cm onto the plate surface of the molded product, and if not broken, the drop height was increased every 10 cm and the presence or absence of cracking or cracking was visually confirmed. The drop height at which two or more cracks or cracks did not occur among three molded articles was defined as the ball impact height. The higher the falling ball impact height, the better the surface impact resistance.

(15) Evaluation of heat resistance In accordance with ISO 75, using an HDT tester (“6A-2” manufactured by Toyo Seiki Seisakusyo Co., Ltd.), the load was 1.80 MPa and the width of the molded product was 4 mm thick. The deflection temperature under load (HDT) was measured. The higher the value of HDT, the better the heat resistance.

"Example 1"
<Production of Copolymer (A)>
150 parts of distilled water, a mixture of 76 parts of methyl methacrylate as vinyl monomer component (m1), 8 parts of N-phenylmaleimide and 16 parts of styrene in a pressure resistant reaction vessel, and 2,2'-azobis (isobutyro ro) (Nitrile) 0.2 part, n-octyl mercaptan 0.25 part and polyvinyl alcohol 0.7 part were charged, the internal temperature was raised to 75 ° C., and the reaction was performed for 3 hours. Then, it heated up to 90 degreeC and reaction was completed by hold | maintaining for 60 minutes. The contents were washed with a centrifugal dehydrator, dehydrated repeatedly, and dried to obtain a copolymer (A-1).
The mass average molecular weight, molecular weight distribution (Mw / Mn), and glass transition temperature of the obtained copolymer (A-1) were measured. These results are shown in Table 1.

<Preparation of Thermoplastic Resin Composition>
Copolymer (A-1) was knead | mixed and pelletized with the extruder, and the thermoplastic resin composition ((alpha) 11) of the pellet was obtained.
Separately, after mixing 100 parts of copolymer (A-1) and 1.5 parts of carbon black (Mitsubishi Chemical Corporation, "Mitsubishi Carbon Black (registered trademark) # 966") using a Henschel mixer, The mixture was kneaded by an extruder and pelletized to obtain a pellet thermoplastic resin composition (β11).
The fluidity of the obtained thermoplastic resin composition (α11) was evaluated. In addition, the surface appearance of the spiral flow molded product was evaluated. These results are shown in Table 1.

<Manufacturing of molded articles>
Injection molding was performed at 230 ° C. and an injection speed of 40 g / sec using pellets of the thermoplastic resin composition (α11) to obtain a molded product (α1) having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm.
Separately, pellets of the thermoplastic resin composition (β11) were injection molded at 230 ° C. and an injection speed of 40 g / sec to obtain a molded article (β1) having a length of 100 mm, a width of 100 mm and a thickness of 2 mm.
The Charpy impact strength of the resulting molded article (α1) was measured to evaluate the heat resistance. These results are shown in Table 1.
Moreover, the pencil hardness and the falling ball impact height were measured about the obtained molded article ((beta) 1), and coloring property was evaluated. The results are shown in Table 1.

"Examples 2 to 10, Comparative Examples 1 to 5"
Copolymers (A-2) to (A-15) were produced in the same manner as in Example 1 except that the blending compositions shown in Tables 1 to 3 were changed, and the resulting copolymer (A -2) to (A-15) were used to produce molded articles, and various measurements and evaluations were performed. These results are shown in Tables 1 to 3.

  As is clear from Tables 1 and 2, the thermoplastic resin compositions obtained in Examples 1 to 10 were high in MVR and excellent in fluidity. In addition, the spiral flow length was long, and the occurrence of silver streaks could be suppressed even if the molding temperature was raised. Further, the molded articles obtained by molding the thermoplastic resin compositions of Examples 1 to 10 had high surface hardness and were excellent in heat resistance, surface appearance, color developability and impact resistance.

On the other hand, as apparent from Table 3, the thermoplastic resin compositions of Comparative Examples 1 to 3 using the copolymers (A-11) to (A-13) having a small ratio of styrene units are inferior in fluidity. The Moreover, the molded article which shape | molded these thermoplastic resin compositions was easy to generate a silver streak, and was inferior to the surface external appearance. In particular, in the case of Comparative Example 3 in which the copolymer (A-13) containing no N-phenylmaleimide unit was used, the heat resistance of the molded article was also inferior.
The thermoplastic resin composition of Comparative Example 4 using the copolymer (A-14) having a large proportion of N-phenylmaleimide units was inferior in fluidity.
In the case of Comparative Example 5 using the copolymer (A-15) having a large proportion of styrene units, although the fluidity of the thermoplastic resin composition is good, the molded product obtained by molding the thermoplastic resin composition is silver Streaks were likely to occur and the surface appearance was poor. Moreover, the surface hardness was low and the color development was also inferior.

"Example 11"
<Production of graft copolymer (B)>
50 parts of polybutyl acrylate (gel content 85%, volume average particle diameter 120 μm), 37.5 parts of styrene, 12.5 parts of acrylonitrile, 0.1 part of t-dodecyl mercaptan, 1.0 part of sodium rosinate, water A reactor was charged with 0.05 part of potassium oxide and 160 parts of pure water, heated to 60 ° C. and allowed to stand for 60 minutes. After impregnating the monomer component with polybutyl acrylate, t-hexyl peroxypi 0.3 part of barato was added, the temperature was raised to 75 ° C. and polymerization was carried out for 2 hours. An antioxidant was added to the obtained latex, and it was poured into a calcium chloride aqueous solution to be solidified, washed, dehydrated and dried to obtain a graft copolymer (B-1). The graft ratio of the graft copolymer (B1) was 60%.

<Preparation of Thermoplastic Resin Composition>
64 parts of the copolymer (A-1) produced in the same manner as in Example 1 and 36 parts of the graft copolymer (B-1) were mixed using a Henschel mixer, then kneaded with an extruder and pelletized. To obtain a pellet thermoplastic resin composition (α21).
Separately, 64 parts of copolymer (A-1), 36 parts of graft copolymer (B-1) and carbon black (Mitsubishi Chemical Corporation, “Mitsubishi Carbon Black (registered trademark) # 966”) After mixing 5 parts with a Henschel mixer, the mixture was kneaded with an extruder and pelletized to obtain a thermoplastic resin composition (β21) of pellets.
The fluidity of the obtained thermoplastic resin composition (α21) was evaluated. In addition, the surface appearance of the spiral flow molded product was evaluated. The results are shown in Table 4.

<Manufacturing of molded articles>
The pellets of the thermoplastic resin composition (α21) were used for injection molding at 230 ° C. and an injection speed of 40 g / second to obtain a molded product (α2) having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm.
Separately, pellets of the thermoplastic resin composition (β21) were injection molded at 230 ° C. and an injection speed of 40 g / sec to obtain a molded article (β2) of 100 mm long, 100 mm wide and 2 mm thickness.
The Charpy impact strength of the obtained molded product (α2) was measured to evaluate the heat resistance. The results are shown in Table 4.
Moreover, the pencil hardness and the falling ball impact height were measured about the obtained molded article ((beta) 2), and coloring property was evaluated. The results are shown in Table 4.

"Examples 12 to 20, Comparative Examples 6 to 10"
A thermoplastic resin composition is produced in the same manner as in Example 11 except that the copolymer (A) of the type shown in Tables 4 to 6 is used, and a molded article is produced using the obtained thermoplastic resin composition. Manufactured, various measurements and evaluations were performed. These results are shown in Tables 4 to 6.

  As is clear from Tables 4 and 5, the thermoplastic resin compositions obtained in Examples 11 to 20 had high MVR and were excellent in fluidity. In addition, the spiral flow length was long, and the occurrence of silver streaks could be suppressed even if the molding temperature was raised. Furthermore, the molded articles obtained by molding the thermoplastic resin compositions of Examples 11 to 20 had high surface hardness and were excellent in heat resistance, surface appearance, color developability and impact resistance.

On the other hand, as apparent from Table 6, the thermoplastic resin compositions of Comparative Examples 6 to 8 using the copolymers (A-11) to (A-13) having a small proportion of styrene units are inferior in fluidity. The Moreover, the molded article which shape | molded these thermoplastic resin compositions was easy to generate a silver streak, and was inferior to the surface external appearance. In the case of the comparative example 8 which used the copolymer (A-13) which does not contain a N-phenyl maleimide unit especially, it was inferior also to the heat resistance of the molded article.
The thermoplastic resin composition of Comparative Example 9 using the copolymer (A-14) having a large proportion of N-phenylmaleimide units was inferior in fluidity.
In the case of Comparative Example 10 using the copolymer (A-15) having a large proportion of styrene units, although the flowability of the thermoplastic resin composition is good, the molded product obtained by molding the thermoplastic resin composition is silver It was prone to streaks and was inferior in surface appearance. Moreover, the surface hardness was low and the color development was also inferior.

  ADVANTAGE OF THE INVENTION According to this invention, it can consist of a resin composition excellent in fluidity | liquidity, and can provide the resin molded product for motor vehicles which is excellent in surface appearance even if it is high in surface hardness, is excellent in heat resistance, and is thin and large. The resin molded article for automobiles of the present invention is suitably used for various interior and exterior resin parts of automobiles. Moreover, since the resin molded article for motor vehicles of the present invention is excellent in color development, the utility value as various interior and exterior resin parts used without coating is high.

10 Automotive resin molded products t Automotive resin molded product thickness L Resin flow length of automotive resin molded products

Claims (3)

A copolymer (A) obtained by polymerizing a vinyl-based monomer component (m1) containing a (meth) acrylic acid ester monomer, an N-substituted maleimide monomer, and an aromatic vinyl monomer An automotive resin molded article comprising a thermoplastic resin composition containing
The content of the (meth) acrylic acid ester monomer is 30 to 92% by mass with respect to the total mass of the vinyl monomer component (m1), and the content of the N-substituted maleimide monomer The resin molded article for motor vehicles whose is 1-25 mass%, and whose content of the said aromatic vinyl monomer is 7-45 mass%. The automotive resin molded product according to claim 1, wherein a thickness t (mm) and a resin flow length L (mm) of the automotive resin molded product satisfy the following formulas (1) and (2).
t <4.0 (1)
L / t> 200 (2)   The thermoplastic resin composition according to claim 1 or 2, further comprising a graft copolymer (B) obtained by graft polymerizing a vinyl monomer component (m2) in the presence of a rubbery polymer. Resin molded products for automobiles.

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