JP2018188546A - Thermoplastic resin composition and molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition capable of giving a molded article excellent in color tone, impact resistance, molding appearance (vapor deposition appearance), weather resistance, and laser welding appearance, and to provide a molded article thereof.SOLUTION: The thermoplastic resin composition contains a thermoplastic resin (A), carbon black (B), and iron (III) oxide (C). As the thermoplastic resin (A), a graft copolymer (A1) is contained which is obtained by polymerizing a vinyl monomer in the presence of a composite rubbery polymer in which a polyorganosiloxane and an alkyl (meth)acrylate polymer are combined. The content of the carbon black (B) is 0.1-3.0 pts.mass based on 100 pts.mass of the thermoplastic resin (A). The content of the iron (III) oxide (C) is 0.1-3.0 pts.mass based on 100 pts.mass of the thermoplastic resin (A). The content x (pts.mass) of the carbon black (B) and the content y (pts.mass) of the iron (III) oxide (C) satisfy a relationship of 0.2≤y/x≤5.SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic resin composition and a molded article thereof.

  As a method of joining molded products made of thermoplastic resin, the laser welding method has increased its usefulness in terms of reducing processing steps, reducing the weight of the joined product, reducing the environmental impact, and the appearance of the joint. . In the laser welding method, usually, two members of a transmitting material that transmits laser light and an absorbing material that absorbs laser light are joined.

  In the laser welding method, if the laser beam to be irradiated is too strong, the amount of heat generated by the absorbent material increases, which causes poor appearance such as foaming, scorching, and discoloration at the welded portion. On the other hand, if the laser beam to be irradiated is too weak, the bonding strength decreases. For this reason, in the laser welding method, it is very important to control the heat generation amount of the absorbing material within an appropriate range.

  By the way, a molded product made of a thermoplastic resin is often used as a colored molded product colored with a pigment. In colored molded articles, color tone is very important from the viewpoint of design. For example, in parts for vehicles, the demand for the black color tone preferred in the market tends to increase year by year.

  Since carbon black, which is a typical black colorant, has high laser light absorbability, it is efficient in melting the resin by increasing the heat generation amount of the colored molded product during laser welding. However, if the content of carbon black is excessively increased, the amount of heat generated by the colored molded product becomes excessive, and therefore, appearance defects such as foaming, scorching, and discoloration tend to be caused at the welded portion during laser welding. That is, when the content of carbon black is increased in order to produce a deep black color in a colored molded product, the appearance after laser welding is deteriorated. Therefore, it is very difficult to achieve both the color tone (particularly blackness) of the colored molded product and the appearance after laser welding.

Patent Document 1 contains a styrene resin and a colorant (carbon black) as a colored styrene resin molded body excellent in laser marking properties and molded appearance (surface gloss), and 0.1 to 10 μm in the molded body. The number of colorants present in the secondary particles is 100 to 20000 / mm ² .

  Patent Document 2 discloses a rubber polymer having a gel content of 70% or more as a thermoplastic resin composition for a lamp housing that improves a defective phenomenon that occurs at the time of laser welding in joining the lamp housing and another member. A rubber-reinforced copolymer resin obtained by polymerizing a vinyl monomer containing an aromatic vinyl compound and a vinyl cyanide compound in the presence, or a (co) polymer of a rubber-reinforced copolymer resin and a vinyl monomer; A combination of a rubber-reinforced resin comprising the above composition and a copolymer containing a maleimide monomer unit and / or a (co) polymer of α-methylstyrene at a specific ratio is disclosed.

JP 2000-309039 A JP 2004-182835 A

  However, in the colored styrene-based resin molded article of Patent Document 1, attention is not paid to achieving both the color tone (particularly blackness) and the appearance after laser welding. The colored styrene resin molded article of Patent Document 1 has technical problems in terms of the balance between blackness as a colored molded article and absorption of laser light in the laser welding method, and impact resistance.

  Also in the thermoplastic resin composition for lamp housing of Patent Document 2, attention is not paid to achieving both the color tone (particularly blackness) of the molded product and the appearance after laser welding. In the molded article made of the thermoplastic resin composition of Patent Document 2, the required level for blackness cannot be sufficiently satisfied.

  The present invention relates to a thermoplastic resin composition capable of obtaining a molded product excellent in color tone, impact resistance, molding appearance (deposition appearance), weather resistance and laser welding appearance; and color tone, impact resistance, molding appearance ( It is an object to provide a molded product having excellent vapor deposition appearance), weather resistance and laser welding appearance.

As a result of intensive studies, the present inventors have solved the above problem by blending carbon black and iron (III) in a specific blending amount with a thermoplastic resin composition containing a specific composite rubber-containing graft copolymer. The inventors have found that the problem can be solved and have reached the present invention.
That is, this invention has the following aspect.

<1> containing a thermoplastic resin (A), carbon black (B), and iron oxide (III) (C); as the thermoplastic resin (A), polyorganosiloxane and alkyl (meth) acrylate heavy A graft copolymer (A1) obtained by polymerizing a vinyl monomer in the presence of a composite rubber-like polymer combined with a polymer; and the content of the carbon black (B) is the thermoplastic It is 0.1-3.0 mass parts with respect to 100 mass parts of resin (A); Content of the said iron (III) (C) is 100 mass parts of the said thermoplastic resin (A). 0.1 to 3.0 parts by mass; the content x (parts by mass) of the carbon black (B) and the content y (parts by mass) of the iron oxide (III) (C) are 0.00. A thermoplastic resin composition satisfying a relationship of 2 ≦ y / x ≦ 5.
<2> The thermoplastic resin composition according to <1>, wherein an average particle diameter of the iron oxide (III) (C) is 1 μm or less.
<3> A molded article comprising the thermoplastic resin composition according to <1> or <2>.

According to the thermoplastic resin composition of the present invention, a molded product excellent in color tone, impact resistance, molded appearance (deposition appearance), weather resistance and laser welding appearance can be obtained.
The molded article of the present invention is excellent in color tone, impact resistance, molded appearance (deposition appearance), weather resistance and laser weld appearance.

The following definitions of terms apply throughout this specification and the claims.
The “molded product” is formed by molding a thermoplastic resin composition.
“Excellent color tone” means that the blackness of the molded product is deep (dark).
“The appearance of laser welding is excellent” means that there is no appearance defect in the welded portion after the molded product is laser welded.
“Poor appearance” means foaming, scorching, discoloration, insufficient welding, etc. at the welded part.
“Alkyl (meth) acrylate” is a general term for alkyl acrylate and alkyl methacrylate.

<Thermoplastic resin composition>
The thermoplastic resin composition of the present invention contains a thermoplastic resin (A), carbon black (B), and iron oxide (III) (C).
The thermoplastic resin composition of the present invention is within the range that does not impair the effects of the present invention, as required, in addition to the thermoplastic resin (A), carbon black (B), and iron oxide (III) (C). An additive may be included.

(Thermoplastic resin (A))
The thermoplastic resin composition of the present invention contains a graft copolymer (A1) as the thermoplastic resin (A).
The thermoplastic resin composition of the present invention may contain only the graft copolymer (A1) as the thermoplastic resin (A); other than the graft copolymer (A1) and the graft copolymer (A1). It may contain other thermoplastic resin (A2). The thermoplastic resin composition of the present invention preferably further contains another thermoplastic resin (A2) as the thermoplastic resin (A) from the viewpoint of the balance between the impact resistance of the molded product and the fluidity of the composition. .

(Graft copolymer (A1))
The graft copolymer (A1) is obtained by polymerizing a vinyl monomer in the presence of a composite rubber-like polymer in which a polyorganosiloxane and an alkyl (meth) acrylate polymer are combined.
In the graft copolymer (A1), it is difficult to specify how the vinyl monomer is polymerized in the presence of the composite rubber-like polymer. For example, vinyl polymers obtained by polymerizing vinyl monomers include those bonded to a composite rubber-like polymer and those not bonded to a composite rubber-like polymer. It is also difficult to specify the molecular weight of the vinyl polymer bonded to the composite rubber-like polymer, the proportion of structural units, and the like. That is, there are circumstances (impossible / impractical circumstances) in which the graft copolymer (A1) cannot be directly identified by its structure or characteristics, or is almost impractical. Therefore, in the present invention, the graft copolymer (A1) is obtained by polymerizing a vinyl monomer in the presence of a composite rubber-like polymer in which a polyorganosiloxane and an alkyl (meth) acrylate polymer are combined. It is more appropriate to define “obtained”.

  The mass ratio of the composite rubber-like polymer and the vinyl polymer in the graft copolymer (A1) is that the composite rubber-like polymer is 10 to 80% by mass, and the vinyl polymer is 20 to 90% by mass. Preferably, the composite rubber-like polymer is 30 to 70% by mass, and the vinyl polymer is more preferably 30 to 70% by mass (however, the total of the composite rubber-like polymer and the vinyl polymer is 100% by mass). And). When the mass ratio of the composite rubbery polymer and the vinyl polymer is within the above range, the impact resistance of the molded product is more excellent.

(Polyorganosiloxane)
The polyorganosiloxane constituting the composite rubber-like polymer is preferably a polyorganosiloxane having a vinyl polymerizable functional group (vinyl polymerizable functional group-containing polyorganosiloxane), a vinyl polymerizable functional group-containing siloxane unit and a dimethylsiloxane unit. More preferred are polyorganosiloxanes having:
Examples of the vinyl polymerizable functional group include a methacryloyl group, an acryloyl group, and a vinyl group.

  The vinyl polymerizable functional group-containing siloxane may be any as long as it has a vinyl polymerizable functional group and can be bonded to dimethylsiloxane via a siloxane bond. As the vinyl polymerizable functional group-containing siloxane, an alkoxysilane compound having a vinyl polymerizable functional group is preferable from the viewpoint of reactivity with dimethylsiloxane.

  Examples of the alkoxysilane compound having a vinyl polymerizable functional group include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ -Methacryloyloxysiloxanes such as methacryloyloxypropylethoxydiethylsilane, γ-methacryloyloxypropyldiethoxymethylsilane, δ-methacryloyloxybutyldiethoxymethylsilane; tetramethyltetravinylcyclotetrasiloxane, p-vinylphenyldimethoxymethylsilane, etc. Vinyl siloxane; and the like.

The vinyl polymerizable functional group-containing siloxane unit possessed by the polyorganosiloxane may be only one type or two or more types.
The content of the vinyl polymerizable functional group-containing siloxane unit is preferably 0.3 to 3 mol% with respect to the total number of moles (100 mol%) of all units constituting the polyorganosiloxane. If the content of the vinyl polymerizable functional group-containing siloxane unit is within the above range, the polyorganosiloxane and the alkyl (meth) acrylate polymer are sufficiently complexed, and the polyorganosiloxane bleeds out on the surface of the molded product. It becomes difficult. Therefore, the surface appearance of the molded product becomes better, and the impact resistance of the molded product is further improved.

  The content of silicon atoms having three or more siloxane bonds in the polyorganosiloxane is preferably 0 to 1 mol% with respect to the total number of moles of all silicon atoms in the polyorganosiloxane. When the content of silicon atoms having three or more siloxane bonds is not more than the upper limit of the above range, the surface appearance of the molded article is further improved.

  As a preferable form of polyorganosiloxane, 0.3 to 3 mol% of vinyl polymerizable functional group-containing siloxane units and 99.7 to 97 mol% of dimethylsiloxane units (however, vinyl polymerizable functional group-containing siloxane units and dimethylsiloxane are used). And a polyorganosiloxane in which the content of silicon atoms having 3 or more siloxane bonds is 1 mol% or less with respect to all silicon atoms.

  The polyorganosiloxane is typically granular. The mass average particle diameter of the polyorganosiloxane is preferably 400 nm or less, and more preferably 300 nm or less, from the viewpoint of further improving the surface appearance of the molded product. The mass average particle size of the polyorganosiloxane can be calculated from the particle size distribution obtained by measuring the mass-based particle size distribution using a capillary type particle size distribution analyzer.

The polyorganosiloxane can be obtained, for example, by polymerizing a siloxane mixture containing a vinyl polymerizable functional group-containing siloxane and a dimethylsiloxane oligomer.
As the dimethylsiloxane oligomer, a dimethylsiloxane ring having 3 or more members is preferable, and a dimethylsiloxane ring having 3 to 7 members is more preferable. Specific examples include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane. A dimethylsiloxane oligomer may be used individually by 1 type, and may use 2 or more types together.

As a method for polymerizing the siloxane mixture, emulsion polymerization is preferred. Emulsion polymerization is usually performed using an emulsifier, water, and an acid catalyst.
As the emulsifier, an anionic emulsifier is preferable. Examples of the anionic emulsifier include sodium alkylbenzene sulfonate, sodium lauryl sulfonate, sodium polyoxyethylene nonylphenyl ether sulfate, and the like. As the anionic emulsifier, sulfonic acid-based emulsifiers such as sodium alkylbenzene sulfonate and sodium lauryl sulfonate are preferable. An emulsifier may be used individually by 1 type and may use 2 or more types together.
0.05-5 mass parts is preferable with respect to 100 mass parts of siloxane mixtures, and, as for the usage-amount of an emulsifier, 1-3 mass parts is more preferable. If the amount of the emulsifier used is equal to or more than the lower limit of the above range, the dispersed state is easily stabilized and the emulsified state having a minute particle diameter is easily maintained. If the usage-amount of an emulsifier is below the upper limit of the said range, coloring of the molded article resulting from an emulsifier can be suppressed.

Examples of the acid catalyst include organic acid catalysts such as sulfonic acids (eg aliphatic sulfonic acid, aliphatic substituted benzene sulfonic acid, aliphatic substituted naphthalene sulfonic acid); inorganic acids such as mineral acids (eg sulfuric acid, hydrochloric acid, nitric acid) A catalyst etc. are mentioned. As the acid catalyst, aliphatic substituted benzene sulfonic acid is preferable, and n-dodecyl benzene sulfonic acid is more preferable because it is excellent in stabilizing the latex of the siloxane latex described later. In addition, when n-dodecylbenzenesulfonic acid and a mineral acid such as sulfuric acid are used in combination, the influence of the color of the emulsifier used in the production of the polyorganosiloxane on the color of the molded product can be reduced. An acid catalyst may be used individually by 1 type, and may use 2 or more types together.
The addition amount of the acid catalyst is usually about 0.1 to 20 parts by mass with respect to 100 parts by mass of the siloxane mixture.

The acid catalyst may be mixed with the siloxane mixture, the emulsifier and water at the timing of mixing; the siloxane mixture, the emulsifier and water are mixed and emulsified to form a latex (siloxane latex), and the siloxane latex is finely divided. Then, it may be mixed with the siloxane latex. From the viewpoint of easily controlling the particle diameter of the polyorganosiloxane, it is preferable to mix the siloxane latex and the acid catalyst after making the siloxane latex fine. In particular, it is preferable to drop the finely divided siloxane latex into the acid catalyst aqueous solution at a constant rate.
When the acid catalyst is mixed with the siloxane mixture, the emulsifier and the water at the timing of mixing them, it is preferable to make them fine after mixing them.

Siloxane latex can be made into fine particles by using, for example, a homomixer or a homogenizer. A homomixer performs microparticulation with a shearing force generated by high-speed rotation. The homogenizer atomizes with a jet output from a high pressure generator.
Examples of the method of mixing the siloxane mixture, the emulsifier, water, and the acid catalyst, and the method of mixing the finely divided siloxane latex and the acid catalyst include mixing by high-speed stirring, mixing by a high-pressure emulsifier such as a homogenizer, and the like. It is done. A method using a homogenizer is preferable from the viewpoint of reducing the particle size distribution of the polyorganosiloxane.

The polymerization temperature is preferably 50 ° C. or higher, and more preferably 80 ° C. or higher.
When the finely divided siloxane latex is dropped into the acid catalyst aqueous solution, the temperature of the acid catalyst aqueous solution is preferably 50 ° C. or higher, and more preferably 80 ° C. or higher.
The polymerization time is preferably 2 hours or longer, and more preferably 5 hours or longer when the acid catalyst is mixed at the timing of mixing the siloxane mixture, the emulsifier and water. In the case of mixing the finely divided siloxane latex and the acid catalyst, it is preferable that the whole amount of the finely divided siloxane latex is dropped into the acid catalyst aqueous solution and then held for about 1 to 10 hours.

  The polymerization is stopped by cooling the reaction solution and neutralizing the reaction solution with an alkaline substance such as sodium hydroxide, potassium hydroxide, sodium carbonate or the like so that the pH of the reaction solution at 25 ° C. is about 6-8. Can be done by.

  The mass average particle diameter of the polyorganosiloxane can be controlled by adjusting the composition of the siloxane mixture, the amount of the acid catalyst used (the content of the acid catalyst in the acid catalyst aqueous solution), the polymerization temperature, and the like. For example, the mass average particle diameter tends to increase as the amount of the acid catalyst used decreases, and the mass average particle diameter tends to decrease as the polymerization temperature increases.

(Alkyl (meth) acrylate polymer)
The alkyl (meth) acrylate polymer constituting the composite rubber-like polymer is a polymer having an alkyl (meth) acrylate unit. The alkyl (meth) acrylate polymer may further have a monomer unit other than the alkyl (meth) acrylate unit.

  Examples of the alkyl (meth) acrylate include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate; hexyl methacrylate, 2-ethylhexyl methacrylate. And alkyl methacrylate esters such as n-lauryl methacrylate. Alkyl (meth) acrylate may be used individually by 1 type, and may use 2 or more types together. 1-12 are preferable and, as for carbon number of the alkyl group which an alkyl (meth) acrylate has, 1-8 are more preferable. As the alkyl (meth) acrylate, n-butyl acrylate is preferable because the impact resistance of the molded product is further improved.

  In the alkyl (meth) acrylate polymer, the content of the alkyl (meth) acrylate unit is preferably 80 to 100% by mass with respect to the total mass of all units constituting the alkyl (meth) acrylate polymer, 90 -100 mass% is more preferable.

  Other monomers include monomers copolymerizable with alkyl (meth) acrylates, such as aromatic vinyl compounds (eg, styrene, α-methylstyrene, p-methylstyrene, etc.), cyanide. Examples thereof include vinyl compounds (for example, acrylonitrile, methacrylonitrile, etc.), acid group-containing monomers (for example, unsaturated compounds having a carboxy group such as (meth) acrylic acid, itaconic acid, crotonic acid), and the like. Another monomer may be used individually by 1 type and may use 2 or more types together.

  The alkyl (meth) acrylate polymer is obtained by polymerizing a monomer component containing at least one alkyl (meth) acrylate. Examples of the polymerization method include known polymerization methods.

(Composite rubbery polymer)
The composite rubber-like polymer constituting the graft copolymer (A1) is a composite of polyorganosiloxane and an alkyl (meth) acrylate polymer.

  The ratio of the polyorganosiloxane and the alkyl (meth) acrylate polymer in the composite rubber-like polymer is not particularly limited. The ratio of the polyorganosiloxane is 2 to 14 out of a total of 100% by mass of the polyorganosiloxane and the alkyl (meth) acrylate polymer, from the viewpoint that the impact resistance and surface appearance of the molded product are more excellent. Mass% is preferred.

The gel content of the composite rubbery polymer is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, and particularly preferably 70 to 85% by mass. When the gel content of the composite rubbery polymer is within the above range, the impact resistance of the molded product is more excellent. The gel content of the composite rubbery polymer can be determined by the following method.
The weighed composite rubber-like polymer was dissolved in an appropriate solvent at room temperature (23 ° C.) for 20 hours, centrifuged, and the supernatant was removed by decantation, and the remaining insoluble matter was removed at 60 ° C. for 24 hours. Dry and weigh. The ratio (mass%) of the insoluble matter with respect to the composite rubber-like polymer weighed first is calculated | required, and let this ratio be gel content of a composite rubber-like polymer. Examples of the solvent used for dissolving the composite rubber-like polymer include toluene and acetone.

  The composite rubbery polymer is typically granular. The volume average particle diameter of the composite rubber-like polymer is preferably 100 to 1000 nm, and more preferably 150 to 500 nm. If the volume average particle diameter of the composite rubber-like polymer is not less than the lower limit of the above range, the impact resistance of the molded product is more excellent. If the volume average particle diameter of the composite rubber-like polymer is not more than the upper limit of the above range, the vapor deposition appearance of the molded product is more excellent. The volume average particle size of the composite rubber-like polymer can be calculated from the particle size distribution obtained by measuring the volume-based particle size distribution using a laser diffraction / scattering type particle size distribution analyzer.

  Examples of the method for producing the composite rubber-like polymer include a method of hetero-aggregating or co-hygrolating a plurality of latexes each containing a polyorganosiloxane and an alkyl (meth) acrylate polymer; a polyorganosiloxane and an alkyl (meth) acrylate Examples thereof include a method of polymerizing a monomer component that forms the other polymer in the presence of a latex containing one of the system polymers to form a composite.

  As a method for producing the composite rubber-like polymer, the volume average particle diameter of the composite rubber-like polymer can be easily adjusted to be within the above-described range. ) The process of radical polymerization of monomer components containing one or more acrylates (radical polymerization process) and the polymer latex and acid group-containing copolymer latex are mixed to enlarge the polymer latex. The method which has the process (enlargement process) made to make it preferable is preferable. This method preferably further includes a step of adding a condensed acid salt to the polymer latex (a condensed acid salt adding step) after the radical polymerization step and before the enlargement step.

Radical polymerization process:
The radical polymerization step is a step of radical polymerizing a monomer component containing at least one alkyl (meth) acrylate in the presence of latex polyorganosiloxane.
The monomer component containing at least one alkyl (meth) acrylate may be added all at once to the latex polyorganosiloxane, or may be added continuously or intermittently.

When radically polymerizing a monomer component containing at least one alkyl (meth) acrylate, one or both of a graft crossing agent and a crosslinking agent may be used as necessary.
Examples of the grafting agent or cross-linking agent include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene, diethylene methacrylate ethylene glycol diester, dimethacrylic acid propylene glycol diester, and dimethacrylic acid 1,3-butylene glycol diester. And 1,4-butylene glycol diester of dimethacrylic acid. These may be used alone or in combination of two or more.

  In radical polymerization, a radical polymerization initiator and an emulsifier are usually used. For example, at room temperature, to the latex of polyorganosiloxane, an emulsifier, a monomer component, and, if necessary, one or both of a graft crossing agent and a crosslinking agent are added, and the temperature is raised to 50 to 100 ° C. A radical polymerization initiator is added to the mixture, and polymerization is carried out until no exothermic polymerization is confirmed, and the state is maintained for about 1 to 5 hours. Thereby, the polymer latex containing the composite rubber in which the polyorganosiloxane and the alkyl (meth) acrylate polymer are combined is obtained.

  Examples of the radical polymerization initiator include peroxides, azo initiators, redox initiators in which an oxidizing agent and a reducing agent are combined. As the radical polymerization initiator, a redox initiator is preferable, and a sulfoxylate initiator obtained by combining ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, sodium formaldehyde sulfoxylate, and hydroperoxide is more preferable.

  As the emulsifier, various carboxylates such as sodium sarcosineate, fatty acid potassium, fatty acid sodium, alkenyl succinate dipotassium, rosin acid soap and the like are preferable from the viewpoint that the stability of the latex during radical polymerization is excellent and the polymerization rate is increased. Dipotassium alkenyl succinate is preferable from the viewpoint that gas generation can be suppressed when the graft copolymer (A1) and the thermoplastic resin composition containing the graft copolymer (A1) are molded at high temperature.

Condensate addition process:
The condensed acid salt addition step is a step of adding a condensed acid salt to the polymer latex obtained in the radical polymerization step prior to the enlargement step. Prior to mixing with the acid group-containing copolymer latex in the enlargement step, the enlargement is facilitated by adding a condensed acid salt to the polymer latex. Therefore, it becomes possible to reduce the addition amount of acid group containing copolymer latex, and it becomes easy to adjust the volume average particle diameter of a composite rubber-like polymer in the range mentioned above.

  Examples of the condensed acid salt include a salt of a condensed acid and an alkali metal and / or an alkaline earth metal. Examples of the condensed acid include phosphoric acid and silicic acid. As the condensed acid salt, a salt of pyrophosphoric acid which is a condensed acid of phosphoric acid and an alkali metal is preferable, and sodium pyrophosphate or potassium pyrophosphate is more preferable.

The addition amount of the condensed acid salt may be adjusted so that the volume average particle diameter of the composite rubber-like polymer is within the above-mentioned range. Usually, the solid content of the polymer latex obtained in the radical polymerization step is 100 mass. 0.1-5 mass parts is preferable with respect to a part, and 0.3-3 mass parts is more preferable. If the addition amount of the condensed acid salt is not less than the lower limit of the above range, the enlargement of the polymer latex is likely to proceed sufficiently. If the addition amount of the condensed acid salt is less than or equal to the upper limit of the above range, the enlargement of the polymer latex proceeds sufficiently, or the polymer latex is easily stabilized, and the generation of a large amount of coagulum can be suppressed. .
The condensed acid salt is preferably added all at once to the polymer latex.

  It is preferable that the polymer latex to which the condensed acid salt is added (a mixture of the polymer latex and the condensed acid salt) at 25 ° C. has a pH of 7 or more. If pH is 7 or more, the enlargement of polymer latex will fully advance easily. In order to make the pH of the polymer latex 7 or more, an alkali compound such as sodium hydroxide or potassium hydroxide can be added.

Enlargement process:
The enlargement process is obtained by a radical polymerization process, and a polymer latex to which a condensation acid salt is added in a condensation acid salt addition process as necessary is mixed with an acid group-containing copolymer latex. This is a process of enlarging the united latex.

  The acid group-containing copolymer has an acid group-containing monomer unit and an alkyl (meth) acrylate unit. If necessary, it may further have other monomer units copolymerizable therewith. As the acid group-containing monomer, an unsaturated compound having a carboxy group is preferable. Examples of the unsaturated compound having a carboxy group include (meth) acrylic acid, itaconic acid, crotonic acid and the like, and (meth) acrylic acid is preferable. An acid group containing monomer may be used individually by 1 type, and may use 2 or more types together.

  Examples of the alkyl (meth) acrylate include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, and methacrylic acid. Examples include ethyl, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate and the like. As alkyl (meth) acrylate, the alkyl (meth) acrylate which has a C1-C8 alkyl group is preferable. Alkyl (meth) acrylate may be used individually by 1 type, and may use 2 or more types together.

  The other monomer is a monomer copolymerizable with the acid group-containing monomer and the alkyl (meth) acrylate, and is a monomer other than the acid group-containing monomer and the alkyl (meth) acrylate. . Other monomers include aromatic vinyl compounds (eg, styrene, α-methylstyrene, p-methylstyrene, etc.), vinyl cyanide compounds (eg, acrylonitrile, methacrylonitrile, etc.), two or more polymerizable Examples thereof include compounds having a functional group (eg, allyl methacrylate, polyethylene glycol ester dimethacrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitic acid, etc.). Another monomer may be used individually by 1 type and may use 2 or more types together.

  As the acid group-containing copolymer, the ratio of the acid group-containing monomer unit to the total mass of all units constituting the acid group-containing copolymer is 5 to 40% by mass, and the alkyl (meth) acrylate unit. The proportion is preferably 60 to 95 mass%, the proportion of other monomer units is 0 to 35 mass%, the proportion of acid group-containing monomer units is 8 to 30 mass%, and the alkyl (meth) acrylate unit Is more preferably 70 to 92% by mass and another monomer unit of 0 to 22% by mass. When the ratio of the acid group-containing monomer unit is 5% by mass or more and the ratio of the alkyl (meth) acrylate unit is 95% by mass or less, sufficient enlargement ability is obtained. If the ratio of the acid group-containing monomer unit is 40% by mass or less and the ratio of the alkyl (meth) acrylate unit is 60% by mass or more, a large amount of agglomerates are produced during the production of the acid group-containing copolymer latex. Can be suppressed. If the ratio of the other monomer units is 35% by mass or less, the acid group-containing copolymer latex can have sufficient enlargement ability.

  The acid group-containing copolymer latex used for enlargement is a monomer containing an acid group-containing monomer, an alkyl (meth) acrylate, and, if necessary, other monomers copolymerizable therewith in water. It is obtained by polymerizing body components. Examples of the polymerization method include a usual emulsion polymerization method. Emulsion polymerization is usually performed using an emulsifier and a radical polymerization initiator.

  As the emulsifier, known emulsifiers can be used, for example, carboxylic acid-based emulsifiers such as alkali metal salts of fatty acids (oleic acid, palmitic acid, stearic acid, rosin acid, etc.), alkali metal salts of alkenyl succinic acid; And anionic emulsifiers such as sodium alkyl sulfonate, sodium alkylbenzene sulfonate, sodium alkyl sulfosuccinate and sodium polyoxyethylene nonylphenyl ether sulfate. An emulsifier may be used individually by 1 type and may use 2 or more types together.

  The emulsifier may be added all at once at the beginning of the polymerization; it may be added continuously or intermittently. Depending on the amount of emulsifier and how it is used, the particle size of the acid group-containing copolymer latex and, in turn, the particle size of the enlarged composite rubber-like polymer latex may be affected. It is preferred to select a method.

  Examples of the radical polymerization initiator include a thermal decomposition initiator and a redox initiator. Examples of the thermal decomposition type initiator include potassium persulfate, sodium persulfate, and ammonium persulfate. Examples of the redox initiator include a combination of an organic peroxide represented by cumene hydroperoxide, sodium formaldehyde sulfoxylate, an iron salt, and the like. A radical polymerization initiator may be used individually by 1 type, and may use 2 or more types together.

  During emulsion polymerization, chain transfer agents such as mercaptans (eg t-dodecyl mercaptan, n-octyl mercaptan, etc.), terpinolene, α-methylstyrene dimer, etc. may be used to adjust the molecular weight, and the pH is adjusted. In order to do so, an alkali or an acid may be added, and an electrolyte may be added as a thickener.

  In the enlargement step, the addition amount of the acid group-containing copolymer latex relative to the polymer latex (solid content equivalent amount) may be adjusted so that the volume average particle diameter of the composite rubber-like polymer is within the above-described range. Usually, 0.1-5 mass parts is preferable with respect to 100 mass parts of solid content of polymer latex, and 0.3-3 mass parts is more preferable. If the addition amount of the acid group-containing copolymer latex is not less than the lower limit of the above range, the enlargement of the polymer latex proceeds sufficiently. Moreover, it can suppress that agglomerates generate | occur | produce in large quantities. If the addition amount of the acid group-containing copolymer latex is less than or equal to the upper limit of the above range, the pH of the enlarged latex can be suppressed from decreasing, and the latex is less likely to become unstable.

The acid group-containing copolymer latex may be added all at once to the polymer latex, or may be added continuously or intermittently by dropping.
It is preferable to appropriately control the stirring during the enlargement. If the stirring is insufficient, unhypertrophic rubbery polymer may remain due to local enlargement. If the stirring is excessive, the enlarged latex becomes unstable and a large amount of coagulum may be generated.
20-90 degreeC is preferable and the temperature at the time of enlarging is more preferable 30-80 degreeC. If the temperature is outside the above range, the polymer latex may not be sufficiently enlarged.

  The composite rubber-like polymer is obtained in a radical polymerization step, and a polymer latex to which a condensed acid salt is added as necessary is enlarged using an acid group-containing copolymer latex, and then an alkyl ( You may manufacture by further adding and polymerizing the monomer component containing 1 or more types of (meth) acrylate.

(Vinyl polymer)
The vinyl polymer constituting the graft copolymer (A1) has a constitutional unit based on a vinyl monomer. A vinyl monomer is a monomer having a polymerizable unsaturated double bond. Examples of vinyl monomers include aromatic vinyl compounds, alkyl (meth) acrylates, vinyl cyanide compounds, and the like.
Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, and the like. Examples of the alkyl (meth) acrylate include methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, and t-butyl acrylate. It is done. Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile. A vinyl monomer may be used individually by 1 type, and may use 2 or more types together. As the vinyl monomer, combined use of styrene and acrylonitrile is preferable because the impact resistance of the molded product is further improved. That is, the vinyl polymer preferably has a styrene unit and an acrylonitrile unit.

(Method for producing graft copolymer (A1))
The graft copolymer (A1) is obtained by polymerizing a vinyl monomer in the presence of a composite rubber-like polymer.
As the polymerization method, an emulsion polymerization method is preferable because it can be controlled so that the reaction proceeds stably. Specifically, a method in which a vinyl monomer is collectively charged into the composite rubber-like polymer latex and then polymerized; a part of the vinyl monomer is first charged into the composite rubber-like polymer latex; Examples include a method in which the remainder is dropped into the polymerization system while polymerizing at any time; a method in which polymerization is performed at any time while dropping the entire amount of the vinyl monomer into the latex of the composite rubber-like polymer. The polymerization of the vinyl monomer may be performed in one stage or may be performed 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 monomer in each stage.

Emulsion polymerization is usually performed using a radical polymerization initiator and an emulsifier. For example, a vinyl monomer is added to a latex of a composite rubber-like polymer containing a composite rubber-like polymer, water and an emulsifier, and the vinyl monomer is radically polymerized in the presence of a radical polymerization initiator.
When performing radical polymerization, various known chain transfer agents may be added in order to control the molecular weight and graft ratio of the graft copolymer (A1) obtained.
Examples of the conditions for radical polymerization include polymerization conditions at 50 to 100 ° C. for 1 to 10 hours.

  Examples of the radical polymerization initiator include peroxides, azo initiators, redox initiators in which an oxidizing agent and a reducing agent are combined. As the radical polymerization initiator, a redox initiator is preferable, and a sulfoxylate initiator obtained by combining ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, sodium formaldehyde sulfoxylate, and hydroperoxide is more preferable.

  As the emulsifier, various carboxylates such as sodium sarcosinate, fatty acid potassium, fatty acid sodium, alkenyl succinate dipotassium, rosin acid soap, etc. are preferable from the viewpoint of excellent stability of the latex during radical polymerization and increasing the polymerization rate. Dipotassium alkenyl succinate is more preferable from the viewpoint of suppressing the generation of gas when the graft copolymer (A1) and the thermoplastic resin composition containing the graft copolymer (A1) are molded at high temperature.

  The mass ratio of the composite rubbery polymer to the vinyl monomer is preferably 10 to 80% by mass for the composite rubbery polymer and 20 to 90% by mass for the vinyl monomer. More preferably, the coalescence is 30 to 70% by mass and the vinyl monomer is 30 to 70% by mass (however, the total of the composite rubber-like polymer and the vinyl monomer is 100% by mass). If the mass ratio of the composite rubber-like polymer and the vinyl monomer is within the above range, the mass ratio of the composite rubber-like polymer and the vinyl polymer in the graft copolymer (A1) is within the above preferred range. It is easy to be inside.

The graft copolymer (A1) obtained by the emulsion polymerization method is usually in a latex state.
As a method for recovering the graft copolymer (A1) from the latex of the graft copolymer (A1), for example, the latex of the graft copolymer (A1) is poured into hot water in which a coagulant is dissolved. A wet method of coagulating in a slurry state by spraying; a spray drying method of recovering the graft copolymer (A1) semi-directly by spraying the latex of the graft copolymer (A1) in a heated atmosphere.

  Examples of the coagulant used in the wet method include inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, and nitric acid; metal salts such as calcium chloride, calcium acetate, and aluminum sulfate, and are selected according to the emulsifier used in the polymerization. . For example, when only carboxylic acid soap such as fatty acid soap and rosin acid soap is used as an emulsifier, one or more of the above-mentioned coagulants can be used. When an emulsifier exhibiting stable emulsifying power even in an acidic region such as sodium alkylbenzene sulfonate is used as the emulsifier, a metal salt is suitable as the coagulant.

  A slurry-like graft copolymer (A1) is obtained by a wet method. As a method for obtaining the dried graft copolymer (A1) from the slurry-like graft copolymer (A1), the remaining emulsifier residue is eluted and washed in water, and this slurry is subjected to centrifuge, press dehydrator Examples include a method of drying with an air dryer etc. after dehydrating by a method; a method of simultaneously performing dehydration and drying with a press dehydrator, an extruder, or the like. By these methods, a powder or particulate graft copolymer (A1) is obtained.

Washing conditions are preferably such that the amount of the emulsifier residue contained in 100% by mass of the graft copolymer (A1) after drying is 0.5 to 2% by mass. If the emulsifier residue in the graft copolymer (A1) is 0.5% by mass or more, the fluidity of the graft copolymer (A1) and the thermoplastic resin composition containing the graft copolymer (A1) tends to be further improved. If the emulsifier residue in the graft copolymer (A1) is 2% by mass or less, generation of gas when the thermoplastic resin composition is molded at high temperature can be suppressed.
The graft copolymer (A1) discharged from the press dehydrator or the extruder can be directly sent to the extruder or the molding machine to obtain a molded product without being recovered.

(Other thermoplastic resin (A2))
Other thermoplastic resins (A2) include, for example, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-α-methylstyrene copolymer (αSAN resin), styrene-maleic anhydride copolymer, acrylonitrile-styrene. -N-substituted maleimide terpolymer, styrene-maleic anhydride-N-substituted maleimide terpolymer, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene-alkyl (meth) acrylate copolymer Polymer (ASA resin), acrylonitrile-ethylene-propylene-diene-styrene copolymer (AES resin), polymethyl methacrylate, polycarbonate resin, polybutylene terephthalate (PBT resin), polyethylene terephthalate (PET resin), polyvinyl chloride , Polyolefin (polyethylene, polypropylene, etc.), styrene elastomer (styrene-butadiene-styrene (SBS), styrene-butadiene (SBR), hydrogenated SBS, styrene-isoprene-styrene (SIS), etc.), various olefin elastomers Various polyester elastomers, polystyrene, methyl methacrylate-styrene copolymer (MS resin), acrylonitrile-styrene-methyl methacrylate copolymer, polyacetal resin, modified polyphenylene ether (modified PPE resin), ethylene-vinyl acetate copolymer Coalescence, polyphenylene sulfide (PPS resin), polyether sulfone (PES resin), polyether ether ketone (PEEK resin), polyarylate, liquid crystal polyester resin, poly De resin (various nylon) and the like. Another thermoplastic resin (A2) may be used individually by 1 type, and may use 2 or more types together.

(Carbon black (B))
Examples of carbon black (B) include channel black, furnace black, lamp black, thermal black, ketjen black, and naphthalene black. Carbon black (B) may be used individually by 1 type, and may use 2 or more types together.

  Carbon black (B) may have a particle surface subjected to secondary treatment. Examples of the secondary treatment include imparting a surface functional group by oxidation treatment, graphitization by a crystal structure by heat treatment in an inert atmosphere, and bandit activation treatment with water vapor or carbon dioxide gas. Examples of the oxidation treatment include treatment with ozone, nitric acid, nitrous acid, sodium hypochlorite, or hydrogen peroxide. The oxidation treatment generates acidic functional groups such as carboxy groups and phenolic hydroxyl groups on the surface of the carbon black (B), thereby improving the wettability and dispersibility of the surface of the carbon black (B).

(Iron oxide (III) (C))
Iron oxide (III) (C) contains iron (III) oxide as a main component. Here, the main component means that the purity of iron (III) oxide (Fe ₂ O ₃ ) is 80% by mass or more. Therefore, iron (III) (C) does not include iron (III) oxide (II) (Fe ₃ O ₄ ), so-called triiron tetroxide.
Examples of iron oxide (III) (C) include pigments (such as red pigments) containing iron (III) oxide as a main component.

The average particle size of iron (III) (C) is preferably 1 μm or less, and more preferably 0.8 μm or less. If the average particle size of iron (III) (C) is not more than the above upper limit value, the molded appearance is excellent.
The average particle size of iron (III) (C) is to randomly select 10 particles from the transmission electron microscope (TEM) observation image, measure the particle size, and average these particle sizes. Is calculated by

(Other additives)
Examples of other additives include various stabilizers (antioxidants, light stabilizers, etc.), lubricants, plasticizers, mold release agents, dyes, pigments, antistatic agents, flame retardants, inorganic fillers, metal powders, and the like. Is mentioned.

(Content of each component)
The thermoplastic resin (A) is preferably composed of 20 to 100% by mass of the graft copolymer (A1) and 0 to 80% by mass of the other thermoplastic resin (A2). ) And 60 to 80% by weight of the other thermoplastic resin (A2) (however, the graft copolymer (A1) and the other thermoplastic resin (A2)) Is 100% by mass). When the content of the graft copolymer (A1) in the thermoplastic resin (A) is 20% by mass or more, the impact resistance, laser weld appearance, and weather resistance of the molded product are more excellent.

  Content of carbon black (B) is 0.1-3.0 mass parts with respect to 100 mass parts of a thermoplastic resin (A), 0.3-2.0 mass parts is preferable, 0.4 -1.0 mass part is more preferable. If the content of carbon black (B) is not less than the lower limit of the above range, the color tone of the molded product is excellent. In addition, sufficient bonding strength can be obtained after laser welding. If the content of carbon black (B) is less than or equal to the upper limit of the above range, scorching and discoloration hardly occur during laser welding, and the laser welding appearance is excellent.

Content of iron oxide (III) (C) is 0.1-3.0 mass parts with respect to 100 mass parts of a thermoplastic resin composition (A), 0.2-1.5 mass parts is Preferably, 0.5 to 1.0 part by mass is more preferable. If the content of iron (III) (C) is not less than the lower limit of the above range, the appearance of the laser-welded article is excellent. In addition, sufficient bonding strength can be obtained after laser welding. If content of iron oxide (III) (C) is below the upper limit of the said range, the color tone and molded external appearance (deposition external appearance) of a molded product will be excellent.

  The content x (parts by mass) of carbon black (B) and the content y (parts by mass) of iron oxide (III) (C) satisfy the relationship of 0.2 ≦ y / x ≦ 5. It is preferable that the relationship of 5 ≦ y / x ≦ 3 is satisfied. If y / x is not less than the lower limit of the above range, sufficient bonding strength can be obtained after laser welding. If y / x is below the upper limit of the said range, the color tone of a molded article will be excellent.

  The content of the other additive is appropriately set according to the type of the other additive. The content of other additives is preferably 10 parts by mass or less, and may be 0 parts by mass with respect to 100 parts by mass of the thermoplastic resin (A).

(Method for producing thermoplastic resin composition)
The thermoplastic resin composition of the present invention includes, for example, a thermoplastic resin (A), carbon black (B), iron oxide (III) (C), and other additives as necessary, a V-type blender, It is produced by mixing with a Henschel mixer or the like, and melt-kneading the mixture using a melt-kneader such as a screw extruder, Banbury mixer, pressure kneader, or mixing roll. Moreover, you may pelletize a melt-kneaded material using a pelletizer etc. as needed.

(Function and effect)
In the thermoplastic resin composition of the present invention described above, the thermoplastic resin (A) containing the specific graft copolymer (A1), carbon black (B), and iron (III) (C) are added. Since it is contained at a specific ratio, when it is formed into a molded product, it has sufficient impact resistance as a resin member, and can exhibit excellent color tone (particularly blackness), weather resistance and molded appearance (deposition appearance). Moreover, when the thermoplastic resin composition of the present invention is formed into a molded article, it is excellent in laser welding appearance and can exhibit sufficient bonding strength.

<Molded product>
The molded article of the present invention is composed of the thermoplastic resin composition of the present invention.
The molded article of the present invention can be produced by molding the thermoplastic resin composition of the present invention.
As the 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, and a blow molding method.

  The molded article of the present invention can be welded by laser welding. For example, a bonded product can be obtained by welding the molded products of the present invention or the molded product of the present invention and another molded product by laser welding. The bonded product is excellent in the appearance of the welded portion and the bonding strength.

  Examples of uses of the molded product of the present invention and the joined product provided with the molded product of the present invention include, for example, vehicle parts (lamps, interiors, exteriors, etc.), OA equipment, home appliance parts, medical instruments, and various industrial materials. A vehicular lamp is preferable.

(Function and effect)
In the molded article of the present invention described above, the thermoplastic resin (A) containing the specific graft copolymer (A1), the carbon black (B), and the iron oxide (III) (C) are in a specific ratio. Since it is a molded article of the thermoplastic resin composition of the present invention contained in the above, it has sufficient impact resistance as a resin member and can exhibit excellent color tone (particularly blackness) and molded appearance (deposition appearance). In addition, the laser welding appearance is excellent and sufficient bonding strength can be expressed.

  Hereinafter, an example is shown concretely. However, the present invention is not limited to the following examples. The following “%” and “part” are based on mass unless otherwise specified.

<Measurement and evaluation>
Various measurements and evaluation methods in Examples and Comparative Examples are as follows.

(Measurement of volume average particle diameter of polymer in latex)
The volume average particle size of the polymer in the latex was determined by a dynamic light scattering method using a dynamic light scattering type particle size distribution measuring device (Nikkiso Co., Ltd., Nanotrac UPA-EX150).

(Measurement of gel content of rubbery polymer)
The weighed rubber-like polymer was dissolved in toluene at room temperature (23 ° C.) for 20 hours, centrifuged, the supernatant was removed by decantation, and the remaining insoluble matter was dried at 60 ° C. for 24 hours. Weighed. The ratio (%) of the insoluble content with respect to the rubber-like polymer weighed first was determined, and this ratio was defined as the gel content of the rubber-like polymer.

(Evaluation of impact resistance (measurement of Charpy impact strength))
In accordance with ISO 3167, a test piece (molded product 1) was produced from the pellet-shaped thermoplastic resin composition of the example or comparative example by an injection molding machine (Toshiba Machine Co., Ltd., IS55FP-1.5A). . The Charpy impact strength of this test piece was measured in a 23 ° C. atmosphere with a notch in accordance with ISO 179-1: 2000.

(Evaluation of laser welding appearance)
From the pellet-shaped thermoplastic resin composition of Example or Comparative Example, using a 4-ounce injection molding machine (manufactured by Nippon Steel Works, Ltd.), a cylinder set temperature of 260 ° C., a mold temperature of 60 ° C., and an injection rate of 20 g / sec. Under the conditions, a plate-shaped test piece (molded product 2) having a length of 100 mm, a width of 100 mm, and a thickness of 2 mm was produced and used as an absorbent.
A permeable material was produced in the same procedure as the absorbent material, except that the thermoplastic resin composition of the example or comparative example was changed to a pellet-like acrylic resin.
A laser is welded with a laser welding machine (manufactured by Leister, NOVOLAS (registered trademark) -C type) on a condition that the output is 3 W, the focal diameter is 2 mm, the scanning speed is 20 mm / second, and the welding length is 30 mm. Light was irradiated from the transmissive material side, and the absorbent material and the transmissive material were welded to obtain a joined product. The appearance of the welded portion of the joined product was visually observed and evaluated according to the following criteria.
○: There is no foaming in the welded part.
(Triangle | delta): There exists foaming in a part of welding part.
X: Foamed or burnt on the entire welded part.

(Evaluation of vapor deposition appearance (diffuse reflectance measurement))
Aluminum was directly deposited on the surface of the molded product 2 using a vacuum deposition apparatus (VPC-1100, manufactured by ULVAC, Inc.) under the conditions of a degree of vacuum of 6.0 × 10 ⁻³ Pa and a film formation rate of 10 kg / second. A 50 nm thick aluminum film was formed. About the film-forming surface of the molded article 2, the diffuse reflectance (%) was measured using a reflectometer (manufactured by Tokyo Denshoku Co., Ltd., TR-1100AD). The lower the value of diffuse reflectance, the more excellent the surface of the molded product is.

(Measurement of color tone)
About the same test piece used for evaluation of the laser welding appearance, the color tone (L ^* ) was measured using a colorimeter. It shows that the blackness of a molded product is deep (dark), so that the value of L ^* is small.

(Evaluation of weather resistance)
Molded product 2 was produced in the same manner as described above. Using an accelerated weathering tester (Suga Test Instruments Co., Ltd., Sunshine Super Long Life Weather Meter WEL-SUN-DCH type), molded product 2 in an environment of 63 ° C., cycle conditions: 60 minutes (rainfall: 12 minutes) Was exposed for 1000 hours. The degree of color change (ΔE) of the molded product 2 before and after exposure for 1000 hours was measured using a color difference meter.

<Production of graft copolymer (A1)>
(Production Example 1)
Production of acid group-containing copolymer latex (K):
In a reactor equipped with a reagent injection container, a condenser, a jacket heater and a stirrer, 200 parts of ion exchange water, 2 parts of potassium oleate, 4 parts of sodium dioctylsulfosuccinate, ferrous sulfate heptahydrate 0.003 Part, 0.009 part of ethylenediaminetetraacetic acid disodium salt and 0.3 part of sodium formaldehyde sulfoxylate were charged under a nitrogen stream, and the temperature was raised to 60 ° C. When the temperature reached 60 ° C., a mixture comprising 85 parts of n-butyl acrylate, 15 parts of methacrylic acid and 0.5 part of cumene hydroperoxide was continuously added dropwise over 120 minutes. After completion of the dropwise addition, ripening was further performed for 2 hours while maintaining the temperature at 60 ° C., the solid content was 33%, the polymerization conversion was 96%, and the acid group-containing copolymer had an acid group content of 120 nm. A copolymer latex (K) was obtained.

(Production Example 2)
Production of polyorganosiloxane (F):
98 parts of octamethylcyclotetrasiloxane and 2 parts of γ-methacryloyloxypropyldimethoxymethylsilane were mixed to obtain 100 parts of a siloxane mixture. To this was added an aqueous solution consisting of 0.67 parts of sodium dodecylbenzenesulfonate and 300 parts of ion-exchanged water, stirred for 2 minutes at 10000 rpm with a homomixer, and then passed twice through the homogenizer at a pressure of 30 MPa. A stable premixed organosiloxane latex was obtained.
Separately, 10 parts of dodecylbenzenesulfonic acid and 90 parts of ion-exchanged water are put into a reactor equipped with a reagent injection container, a cooling tube, a jacket heater and a stirrer, and a 10% aqueous solution of dodecylbenzenesulfonic acid (acid A catalyst aqueous solution) was prepared.
With the acid catalyst aqueous solution heated to 85 ° C., the premixed organosiloxane latex was added dropwise over 2 hours. After the completion of the addition, the temperature was maintained for 3 hours, and then cooled to 40 ° C. or lower. Next, this reaction product was neutralized to pH 7.0 with a 10% aqueous sodium hydroxide solution to obtain a latex of polyorganosiloxane (F).
When 2 g of the obtained polyorganosiloxane (F) latex was dried at 180 ° C. for 30 minutes and the solid content was determined, it was 18.2%. Moreover, the mass average particle diameter of the polyorganosiloxane (F) in the latex was 50 nm.

(Production Example 3)
Production of graft copolymer (A1-1):
In a reactor equipped with a reagent injection container, a condenser, a jacket heater and a stirrer, 2.0 parts of polyorganosiloxane latex (F) in terms of solid content, 0.8 part of dipotassium alkenyl succinate, 190 parts of ion exchange water was charged and mixed. Then, a mixture consisting of 48.0 parts of n-butyl acrylate, 0.6 part of allyl methacrylate, 0.1 part of 1,3-butylene glycol dimethacrylate and 0.1 part of t-butyl hydroperoxide was added. The atmosphere was purged with nitrogen by passing a nitrogen stream through the reactor, and the internal temperature was raised to 60 ° C. When the internal temperature reached 60 ° C., from 0.000075 part of ferrous sulfate heptahydrate, 0.00023 part of ethylenediaminetetraacetic acid disodium salt, 0.2 part of sodium formaldehyde sulfoxylate and 10 parts of ion-exchanged water The resulting aqueous solution was added to initiate radical polymerization. After the polymerization exotherm is confirmed, the jacket temperature is set to 75 ° C., the polymerization is continued until the polymerization exotherm is not confirmed, and this state is maintained for another hour, and a composite rubber in which polyorganosiloxane and polybutyl acrylate rubber are combined. Latex was obtained. The volume average particle diameter of the composite rubber was 90 nm.
After the liquid temperature inside the reactor dropped to 70 ° C., 0.60 part of 5% sodium pyrophosphate aqueous solution was added to the composite rubber latex as a solid content. After controlling the internal temperature to 70 ° C., 0.60 parts of acid group-containing copolymer latex (K) as a solid content is added to the latex of the composite rubber and stirred for 30 minutes to enlarge, A combined latex was obtained. The volume average particle diameter of the composite rubber-like polymer was 180 nm, and the gel content was 88%.

An aqueous solution comprising 0.001 part of ferrous sulfate heptahydrate, 0.003 part of ethylenediaminetetraacetic acid disodium salt, 0.3 part of Rongalite, and 10 parts of ion-exchanged water was added to the latex of the composite rubber-like polymer. Subsequently, a mixed liquid composed of 10 parts of acrylonitrile, 30 parts of styrene, and 0.18 part of t-butyl hydroperoxide was dropped over 80 minutes for polymerization. After completion of dropping, the mixture is kept at a temperature of 75 ° C. for 30 minutes, and then a mixture comprising 2.5 parts of acrylonitrile, 7.5 parts of styrene, 0.05 part of t-butyl hydroperoxide and 0.02 part of n-octyl mercaptan. Was added dropwise over 20 minutes to polymerize. After completion of dropping, after maintaining the temperature at 75 ° C. for 30 minutes, 0.05 part of cumene hydroperoxide was added, and after maintaining the temperature at 75 ° C. for 30 minutes, the mixture was cooled to form a composite rubber-like polymer. A latex of a silicone / acrylic composite rubber graft copolymer (A1-1) obtained by graft polymerization of acrylonitrile and styrene was obtained.
150 parts of a 1% calcium acetate aqueous solution was heated to 60 ° C., and 100 parts of the latex of the graft copolymer (A1-1) was gradually dropped into the solution to be solidified. The precipitate was separated, dehydrated, washed and dried to obtain a graft copolymer (A1-1).

(Production Example 4)
Production of graft copolymer (A1′-2):
In a reactor equipped with a reagent injection container, a cooling tube, a jacket heater and a stirrer, 150 parts of ion-exchanged water and polybutadiene latex (volume average particle size 0.2 μm, gel content 84%) in terms of solid content are 50. Parts, 1 part of disproportionated potassium rosinate and 0.03 part of potassium hydroxide, and after heating to 60 ° C., 0.007 part of ferrous sulfate heptahydrate, 0.1 part of sodium pyrophosphate, 0 of crystalline glucose 3 parts were added. Subsequently, a mixed liquid composed of 15 parts of acrylonitrile, 35 parts of styrene, 0.4 part of cumene hydroperoxide, and 0.5 part of t-dodecyl mercaptan was dropped over 120 minutes for polymerization. After completion of dropping, after maintaining the state at a temperature of 70 ° C. for 60 minutes, 0.05 part of cumene hydroperoxide was added, and after maintaining the state at a temperature of 70 ° C. for 30 minutes, cooling was performed, and polybutadiene was added with acrylonitrile and styrene. A latex of a polybutadiene-based graft copolymer (A1′-2) obtained by graft polymerization was obtained.
An antioxidant was added to the latex. 150 parts of a 1% sulfuric acid aqueous solution was heated to 60 ° C., and 100 parts of latex of the graft copolymer (A1′-2) was gradually dropped into the solution to be solidified. The precipitate was separated, dehydrated, washed and dried to obtain a graft copolymer (A1′-2).

(Production Example 5)
Production of graft copolymer (A1′-3):
In a reactor equipped with a reagent injection container, a condenser, a jacket heater and a stirrer, 2.0 parts of polybutadiene latex (volume average particle diameter 200 nm) in terms of solid content, 0.8 part of dipotassium alkenyl succinate, Then, 190 parts of ion-exchanged water was charged and mixed. Next, a mixture consisting of 48.0 parts of n-butyl acrylate, 0.6 part of allyl methacrylate, 0.1 part of 1,3-butylene glycol dimethacrylate, and 0.1 part of t-butyl hydroperoxide was added. The atmosphere was purged with nitrogen by passing a nitrogen stream through the reactor, and the internal temperature was raised to 60 ° C. When the internal temperature reached 60 ° C., from 0.000075 part of ferrous sulfate heptahydrate, 0.00023 part of ethylenediaminetetraacetic acid disodium salt, 0.2 part of sodium formaldehyde sulfoxylate, 10 parts of ion-exchanged water The resulting aqueous solution was added to initiate radical polymerization. After the polymerization exotherm is confirmed, the jacket temperature is set to 75 ° C., and the polymerization is continued until the polymerization exotherm is not confirmed, and this state is maintained for another hour, and a composite rubber latex in which polybutadiene and polybutyl acrylate rubber are combined. Got. The volume average particle diameter of the composite rubber was 280 nm.
After the liquid temperature inside the reactor dropped to 70 ° C., 0.60 part of 5% sodium pyrophosphate aqueous solution was added to the composite rubber latex as a solid content. After controlling the internal temperature to 70 ° C., 0.60 parts of acid group-containing copolymer latex (K) as a solid content is added to the latex of the composite rubber and stirred for 30 minutes to enlarge, A combined latex was obtained. The volume average particle diameter of the composite rubber-like polymer was 300 nm, and the gel content was 83%.

An aqueous solution comprising 0.001 part of ferrous sulfate heptahydrate, 0.003 part of ethylenediaminetetraacetic acid disodium salt, 0.3 part of Rongalite, and 10 parts of ion-exchanged water was added to the latex of the composite rubber-like polymer. Subsequently, a mixed liquid composed of 10 parts of acrylonitrile, 30 parts of styrene, and 0.18 part of t-butyl hydroperoxide was dropped over 80 minutes for polymerization. After completion of dropping, the mixture is kept at a temperature of 75 ° C. for 30 minutes, and then a mixture comprising 2.5 parts of acrylonitrile, 7.5 parts of styrene, 0.05 part of t-butyl hydroperoxide and 0.02 part of n-octyl mercaptan. Was added dropwise over 20 minutes to polymerize. After completion of dropping, after maintaining the temperature at 75 ° C. for 30 minutes, 0.05 part of cumene hydroperoxide was added, and after maintaining the temperature at 75 ° C. for 30 minutes, the mixture was cooled to form a composite rubber-like polymer. A latex of a graft copolymer (A1′-3) based on butadiene / acrylic composite rubber obtained by graft polymerization of acrylonitrile and styrene was obtained.
150 parts of a 1% calcium acetate aqueous solution was heated to 60 ° C., and 100 parts of a latex of the graft copolymer (A1′-3) was gradually dropped into the solution to be solidified. The precipitate was separated, dehydrated, washed and dried to obtain a graft copolymer (A1′-3).

(Production Example 6)
Production of graft copolymer (A1′-4):
In a reactor equipped with a reagent injection container, a condenser, a jacket heater and a stirrer, 190 parts of ion exchange water, 0.6 part of dipotassium alkenyl succinate, 50 parts of n-butyl acrylate, 0.6 part of allyl methacrylate , A mixture consisting of 0.1 part of t-butyl hydroperoxide was added. The atmosphere was purged with nitrogen by passing a nitrogen stream through the reactor, and the internal temperature was raised to 55 ° C. When the internal temperature reaches 55 ° C., from ferrous sulfate heptahydrate 0.0001 part, ethylenediaminetetraacetic acid disodium salt 0.0003 part, sodium formaldehyde sulfoxylate 0.2 part, ion exchange water 10 parts The resulting aqueous solution was added to initiate radical polymerization. After the polymerization exotherm was confirmed, the jacket temperature was set to 75 ° C., and the polymerization was continued until no polymerization exotherm was confirmed, and this state was maintained for 1 hour to obtain a rubber-like polymer latex. The volume average particle diameter of the rubber-like polymer was 100 nm.
After the liquid temperature inside the reactor dropped to 70 ° C., 0.6 part of 5% sodium pyrophosphate aqueous solution as a solid content was added to the rubber-like polymer latex. After controlling the internal temperature to 70 ° C., 1.2 parts of acid group-containing copolymer latex (K) as a solid content is added to the latex of the rubber-like polymer, and the mixture is stirred for 30 minutes to enlarge the rubber-like polymer. A polymer latex was obtained. The volume average particle diameter of the rubber-like polymer was 290 nm, and the gel content was 85%.

An aqueous solution comprising 0.001 part of ferrous sulfate heptahydrate, 0.003 part of ethylenediaminetetraacetic acid disodium salt, 0.3 part of sodium formaldehyde sulfoxylate, and 10 parts of ion-exchanged water is added to the latex of the rubber-like polymer. Added. Next, a mixed liquid consisting of 15 parts of acrylonitrile, 35 parts of styrene, and 0.225 part of t-butyl hydroperoxide was dropped over 100 minutes to polymerize. After completion of the dropwise addition, the state at a temperature of 80 ° C. was maintained for 30 minutes, 0.05 parts of cumene hydroperoxide was added, and the state at a temperature of 75 ° C. was maintained for 30 minutes, followed by cooling, and the graft copolymer (A1 A latex of '-4) was obtained.
100 parts of a 1.5% sulfuric acid aqueous solution was heated to 80 ° C., and 100 parts of the latex of the graft copolymer (A1′-4) was gradually dropped into the solution to be solidified. The precipitate was separated, dehydrated, washed and dried to obtain a graft copolymer (A1′-4).

<Manufacture of other thermoplastic resin (A2)>
(Production Example 7)
Production of other thermoplastic resins (A2-1):
27 parts of acrylonitrile and 73 parts of styrene were polymerized by a known suspension polymerization method to obtain an acrylonitrile-styrene copolymer having a reduced viscosity of 0.61 dL / g measured from an N, N-dimethylformamide solution at 25 ° C. . This was used as another thermoplastic resin (A2-1).

(Production Example 8)
Production of other thermoplastic resins (A2-2):
Acrylonitrile-styrene having 19 parts of acrylonitrile, 53 parts of styrene and 28 parts of N-phenylmaleimide polymerized by a known continuous solution polymerization method and having a reduced viscosity of 0.65 dL / g measured from an N, N dimethylformamide solution at 25 ° C. An —N-phenylmaleimide terpolymer was obtained. This was used as another thermoplastic resin (A2-2).

<Carbon black (B)>
Carbon black (B-1): RB-92995S manufactured by Koshigaya Chemical Co., Ltd.

<Iron oxide (III) (C), etc.>
Iron oxide (III) (C-1): manufactured by Toda Kogyo Co., Ltd., 130ED, red pigment mainly composed of iron oxide (III), average particle size of 0.2 μm.
Iron oxide (III) (C-2): manufactured by Titanium Industry Co., Ltd., R-110-7, a red pigment mainly composed of iron (III) oxide, an average particle size of 0.7 μm.
Iron oxide (III) Iron (II) (C′-3): Toda Kogyo Co., Ltd., KN-320, black pigment mainly composed of iron oxide (III) iron (II), average particle size 0.3 μm.
Iron oxide (III) Iron (II) (C′-4): manufactured by Titanium Industry Co., Ltd., ABL-205, black pigment mainly composed of iron (III) iron (II), average particle size 0.3 μm.

<Preparation of thermoplastic resin composition>
(Examples 1-7, Comparative Examples 1-10)
Graft copolymers (A1) of the types and amounts shown in Table 1 and Table 2, other thermoplastic resins (A2) carbon black (B) and iron (III) (C), and 1 part of ethylenebisstearylamide, 0.2 parts of silicone oil (manufactured by Dow Corning Toray, SH200), 0.2 part of phenolic antioxidant (manufactured by ADEKA, ADK STAB AO-60) and hindered amine light stabilizer (manufactured by ADEKA, 0.4 part of ADK STAB LA-57) was mixed using a Henschel mixer. The mixture was melt-kneaded at 250 ° C. using a screw type extruder (manufactured by Nippon Steel Works, Ltd., TEX-30α type twin screw extruder), then pelletized by a pelletizer and formed into a pellet-shaped thermoplastic resin composition. Got.
The thermoplastic resin composition was evaluated for impact resistance, laser welding appearance, molding appearance (deposition appearance), color tone, and weather resistance according to the procedure described above. These results are shown in Tables 1 and 2.

As shown in Tables 1 and 2, from the thermoplastic resin compositions obtained in each Example, molded products having excellent impact resistance, laser welding appearance, molding appearance (deposition appearance), color tone and weather resistance are obtained. Obtained.
On the other hand, in the case of each comparative example, the result was inferior to any one or more of the impact resistance, laser welding appearance, molding appearance (deposition appearance), color tone, and weather resistance of the molded product.
Specifically, in the case of Comparative Example 1, since the content of carbon black (B) was large, the laser welding appearance was inferior.
In Comparative Example 2, since the content of carbon black (B) was small, the laser welding appearance and color tone were inferior.
In the case of Comparative Example 3, since the content of iron (III) (C) was large, the laser welding appearance, the molding appearance (deposition appearance), and the color tone were inferior.
In the case of Comparative Example 4, since the content of iron (III) (C) was small, the laser welding appearance was inferior.
In Comparative Examples 5 and 6, since the pigment did not contain iron (III) oxide as a main component, the laser welding appearance was inferior.
In the case of Comparative Example 7, since the graft copolymer (A1) was not included, the impact resistance was inferior.
In Comparative Examples 8 and 9, since the specific graft copolymer (A1) was not included and another graft copolymer was included instead, the weather resistance was poor.
In the case of Comparative Example 10, since the graft copolymer (A1) was not included and another graft copolymer was included instead, the impact resistance was inferior.

  According to the present invention, there is provided a thermoplastic resin composition that is excellent in color tone, molding appearance (deposition appearance), weather resistance and laser welding appearance, and can obtain a molded article having sufficient impact resistance as a resin member. can do. In particular, the balance between the color tone of the molded product of the present invention, the molding appearance (deposition appearance) and the laser welding appearance is at a very high level that cannot be obtained with a conventionally known thermoplastic resin composition. The products have extremely high utility value as vehicle parts (lamps, interiors, exteriors, etc.), OA equipment, home appliance parts, medical instruments, and various industrial materials.

Claims (3)

Including thermoplastic resin (A), carbon black (B), and iron oxide (III) (C),
A graft copolymer obtained by polymerizing a vinyl monomer in the presence of a composite rubber-like polymer in which a polyorganosiloxane and an alkyl (meth) acrylate polymer are combined as the thermoplastic resin (A). Including (A1),
The carbon black (B) content is 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the thermoplastic resin (A).
The content of iron oxide (III) (C is 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the thermoplastic resin (A),
The content x (parts by mass) of the carbon black (B) and the content y (parts by mass) of the iron oxide (III) (C) satisfy the relationship of 0.2 ≦ y / x ≦ 5. Thermoplastic resin composition.   The thermoplastic resin composition according to claim 1, wherein an average particle diameter of the iron oxide (III) (C) is 1 µm or less.   A molded article comprising the thermoplastic resin composition according to claim 1.