JP2020204035A - Thermoplastic resin composition - Google Patents

Abstract

To provide a thermoplastic resin composition capable of obtaining a molded product which is excellent in color tone and appearance after laser welding and has sufficient impact resistance and weather resistance as a resin member, and to provide a molded product formed from a thermoplastic resin composition which is excellent in color tone and appearance after laser welding and has sufficient impact resistance and weather resistance as a resin member.SOLUTION: Reflectivity in a visible light region and absorptivity in a near-infrared region of a thermoplastic resin composition containing a graft copolymer using a composite rubbery polymer obtained by combining polyorganosiloxane and an alkyl(meth)acrylate polymer are controlled in a certain range.SELECTED DRAWING: None

Description

The present invention relates to a thermoplastic resin composition.

With the development of technology, resins have been expanding their application fields more and more in recent years, such as vehicle parts, home appliance parts, and various industrial materials. Secondary processing technology related to resin bonding is also one of the technologies that contributes to its expansion.
Resin joining includes, for example, mechanical joining with screws and bolts, joining with adhesives such as hot melt, thermal joining by applying heat to melt, and vibrating the joint. Examples include vibration welding using the generated frictional heat, and laser welding using the absorption heat generated at the joint by irradiating the joint with laser light. Recently, hot plate welding, vibration welding, and laser welding have been increasing their usefulness from the viewpoints of reducing the processing process, reducing the weight, and reducing the environmental load.

In laser welding, usually, two materials, a "transmissive material" that transmits laser light and an "absorbent material" that absorbs laser light, are joined. The laser beam radiated from the transmissive material side to the material contact interface without contact passes through the transmissive material as it is and reaches the surface of the absorbent material. The light energy absorbed on the surface of the absorber is converted into heat and melts the irradiated area. Further, the heat of fusion is also transferred to the transmission material, and the transmission material is also melted. After that, the melted portion is solidified and fused with cooling. The resin bonded body laser-welded through such a process is excellent in strength, airtightness, appearance (no burrs, etc.), and is also very good in terms of work environment and damage to internal parts. It has the feature.

However, if the laser beam irradiation is too strong, the calorific value of the resin increases, which causes poor appearance such as foaming, charring, and discoloration. On the other hand, if the irradiation of the laser beam is too weak, the bonding strength may be lowered, and in some cases, insufficient welding may occur. Therefore, it is very important to control the calorific value of the resin in an appropriate range for laser welding.

From the viewpoint of controlling the calorific value, a method of adjusting the optical properties of the material with respect to the laser light can be considered. As such a technique, for example, Patent Documents 1 to 3 disclose a resin composition exhibiting a predetermined transmittance for a specific wavelength or a wavelength in a specific range.
However, all of the resin compositions described in Patent Documents 1 to 3 allow laser light having a sufficient amount of energy to reach the welded portion by defining the transmittance to a certain value or higher, that is, they are used as a "transmissive material". It is a thing, and it is not a suitable technology to use as an "absorbent material".

The light incident on the material is divided into transmitted light, reflected light, and absorbed light. That is, when the ratio of the incident light is 100%, the transmittance + reflectance + absorption rate = 100% is established as the ratio of each light component. In the case of the "transmissive material", attention is paid to the transmittance from the viewpoint of allowing the laser light to reach the welded portion. On the other hand, in the case of the "absorbent material", the optical characteristic to be noted is not the transmittance but the absorption rate from the viewpoint of controlling the calorific value within an appropriate range. The reason is that when the absorbent material is thermally melted by the energy of the laser light, if the amount absorbed is excessive, the appearance is poor such as foaming, charring, and discoloration, and if it is too small, the welding becomes insufficient. This is to cause a problem. As described above, it is very important to control the absorption rate of the "absorbent material" in order to obtain a molded product having excellent laser weldability.

By the way, molded products obtained from thermoplastic resins are usually used in a state of being colored by dyeing / pigment (colored molded products), and the color tone is very important from the viewpoint of product design. .. In principle, such a color tone is the result of observing light of various wavelengths in the visible light region reflected by the material with the human eye. The color tone changes variously depending on the wavelength of the light reflected by the material, but the dark color tone such as black and dark gray indicates that the reflectance of light in the visible light region is generally low. In other words, from the viewpoint of color tone control, the optical characteristic to be noted is the reflectance in the visible light region, and it is important to control the reflectance in the visible light region in a specific low range, especially in dark color tones. ..

As for the wavelength of light in laser welding, light having a wavelength in the near infrared region is preferably used because it is excellent in oscillation efficiency. On the other hand, the wavelength of light in the color tone corresponds to the light having a wavelength in the visible light region as described above. That is, by appropriately controlling the absorption rate in the near infrared region and the reflectance in the visible light region, it is possible to provide a material having excellent laser weldability and color tone. Further, a feature of the present invention is to provide a material having an extremely excellent balance between laser weldability and color tone by appropriately controlling the ratio of the absorption rate in the near infrared region to the reflectance in the visible light region. Is possible.

Japanese Patent No. 4017994 JP-A-2007-8974 JP-A-2007-269890

An object of the present invention is to provide a thermoplastic resin composition which is excellent in color tone and appearance after laser welding and can obtain a molded product having sufficient impact resistance and weather resistance as a resin member. Another object of the present invention is to provide a molded product made of a thermoplastic resin composition having excellent color tone and appearance after laser welding, and having sufficient impact resistance and weather resistance as a resin member.

As a result of diligent studies by the present inventors, the visible light region of a thermoplastic resin composition containing a graft copolymer using a composite rubber-like polymer in which a polyorganosiloxane and an alkyl (meth) acrylate-based polymer are compounded. The present invention has been completed by finding that the above-mentioned problems can be solved by appropriately controlling the reflectance and the absorption rate in the near-infrared region.

That is, the present invention includes the following aspects.
[1] A graft copolymer in which a vinyl-based polymer (D) is grafted onto a composite rubber-like polymer (C) in which a polyorganosiloxane (A) and an alkyl (meth) acrylate-based polymer (B) are composited. A thermoplastic resin composition containing E).
When the light reflectance (% R) and the light absorption rate (% A) represented by the following formula (1) are measured in the visible light region to the near infrared light region at a wavelength interval of 1 nm,
The average value (visible% R) of the light reflectance from 380 nm to 780 nm is 5% to 10%.
A thermoplastic resin composition satisfying that the average value (near infrared% A) of the light absorption rate from 780 nm to 1180 nm is 25% to 93%.
Light Absorption Rate (% A) = 100-Light Transmittance (% T) -Light Reflectance (% R) ... (1)
[2] The ratio (near infrared% A / visible% R) of the average value of the light reflectance in the near infrared region and the average value of the light reflectance in the visible light region is 16.5 to 4.5. The thermoplastic resin composition according to [1].
[3] A molded product obtained by molding the thermoplastic resin composition according to [1] or [2].

According to the thermoplastic resin composition of the present invention, it is possible to obtain a molded product having excellent color tone and appearance after laser welding, and having sufficient impact resistance and weather resistance as a resin member.
The molded product of the present invention is excellent in color tone and appearance after laser welding, and has sufficient impact resistance and weather resistance as a resin member.

Hereinafter, the present invention will be described in detail.
In the following description, the "molded article" is a product obtained by molding the thermoplastic resin composition of the present invention. Further, unless otherwise specified in the following description, "excellent in color tone" means that the molded product exhibits a dark color tone (dark gray, black, etc.). Further, "excellent welding appearance" means that charring and discoloration are suppressed at the joint portion after laser welding.

"Thermoplastic resin composition"
The thermoplastic resin composition of the present invention contains the graft copolymer (E).

<Graft copolymer (E)>
The graft copolymer (E) is a composite rubber-like polymer (C) in which a polyorganosiloxane (A) and an alkyl (meth) acrylate-based polymer (B) are composited, and a vinyl-based polymer (D) is grafted onto the composite rubber-like polymer (C). It is a polymerized copolymer.

<Polyorganosiloxane (A)>
The polyorganosiloxane (A) constituting the composite rubber-like polymer (C) is not particularly limited, but a polyorganosiloxane containing a vinyl polymerizable functional group (polyorganosiloxane containing a vinyl polymerizable functional group) is preferable, and vinyl is preferable. A polyorganosiloxane having a polymerizable functional group-containing siloxane unit and a dimethylsiloxane unit is more preferable.
The ratio of the vinyl polymerizable functional group-containing siloxane unit is preferably 0.3 to 3 mol%. When the ratio of the vinyl polymerizable functional group-containing siloxane unit is within the above range, the polyorganosiloxane (A) and the alkyl (meth) acrylate-based polymer (B) are sufficiently composited, and the polyorgano is formed on the surface of the molded product. The siloxane (A) is less likely to bleed out. Therefore, the surface appearance of the molded product is improved, and the impact resistance of the molded product is further improved.

As the polyorganosiloxane (A), since the surface appearance of the molded product is further improved, the silicon atom having three or more siloxane bonds is 0 to 1 mol% with respect to the total silicon atom in the polyorganosiloxane. Is preferable.
Preferred embodiments of the polyorganosiloxane (A) include a vinyl polymerizable functional group-containing siloxane unit of 0.3 to 3 mol% and a dimethylsiloxane unit of 99.7 to 97 mol% (however, a vinyl polymerizable functional group-containing siloxane unit). And dimethylsiloxane units total 100 mol%.) Polyorganosiloxane in which the silicon atom having 3 or more siloxane bonds is 1 mol% or less with respect to the total silicon atom in the polyorganosiloxane is mentioned. Be done.

The average particle size of the polyorganosiloxane (A) is not particularly limited, but is preferably 400 nm or less, more preferably 150 nm or less, because the surface appearance of the molded product is further improved. The lower limit is preferably 20 nm or more.
Here, the average particle size of the polyorganosiloxane (A) is a value (mass average particle size) calculated from the mass-based particle size distribution measured by using a particle size distribution measuring device. is there.

(Manufacturing method of polyorganosiloxane (A))
The polyorganosiloxane (A) can be obtained, for example, by polymerizing a siloxane mixture containing dimethylsiloxane and a vinyl-polymerizable functional group-containing siloxane. The method of polymerization is not particularly limited, but emulsion polymerization is preferable.

As the dimethylsiloxane, a dimethylsiloxane-based cyclic body having a 3-membered ring or more is preferable, and a dimethylsiloxane-based cyclic body having a 3- to 7-membered ring is more preferable. Specific examples thereof include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane. These dimethylsiloxanes may be used alone or in combination of two or more.

The vinyl polymerizable functional group-containing siloxane is not particularly limited as long as it contains a vinyl polymerizable functional group and can be bonded to dimethylsiloxane via a siloxane bond, but the reactivity with dimethylsiloxane is taken into consideration. , Various alkoxysilane compounds containing a vinyl polymerizable functional group are suitable. Specifically, β-methacryloyloxyethyl dimethoxymethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylethoxydiethylsilane, Methacryloyloxysiloxane such as γ-methacryloyloxypropyldiethoxymethylsilane, δ-methacryloyloxybutyldiethoxymethylsilane; vinylsiloxane such as tetramethyltetravinylcyclotetrasiloxane; p-vinylphenyldimethoxymethylsilane, γ-mercaptopropyldimethoxy Examples thereof include mercaptosiloxane such as methylsilane and γ-mercaptopropyltrimethoxysilane. These vinyl polymerizable functional group-containing siloxanes may be used alone or in combination of two or more.

Polymerization of the siloxane mixture is usually carried out using an emulsifier, water and an acid catalyst.
As the emulsifier, an anionic emulsifier is preferable. Specific examples thereof include sodium alkylbenzene sulfonate, sodium lauryl sulfonate, sodium polyoxyethylene nonylphenyl ether sulfate, and the like. Among these, sulfonic acid-based emulsifiers such as sodium alkylbenzene sulfonate and sodium lauryl sulfonate are preferable. These emulsifiers may be used alone or in combination of two or more.
The amount of the emulsifier used is preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the siloxane mixture. When the amount of the emulsifier used is 0.05 parts by mass or more, the dispersed state is likely to be stable, and the emulsified state with a fine particle size is easily maintained. On the other hand, when the amount of the emulsifier used is 5 parts by mass or less, coloring of the molded product due to the emulsifier can be suppressed.

Examples of the acid catalyst include organic acid catalysts such as sulfonic acids (for example, aliphatic sulfonic acids, aliphatic substituted benzenesulfonic acids, aliphatic substituted naphthalene sulfonic acids, etc.); and inorganic acids such as mineral acids (for example, sulfuric acid, hydrochloric acid, nitric acid, etc.). Examples include catalysts. These acid catalysts may be used alone or in combination of two or more.
Among these, aliphatic-substituted benzenesulfonic acid is preferable, and n-dodecylbenzenesulfonic acid is particularly preferable because it is also excellent in stabilizing the latex of the siloxane latex (a) described later. Further, 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 for producing the polyorganosiloxane (A) on the color of the molded product can be suppressed to a small extent.
The amount of the acid catalyst added may be appropriately determined, but 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 at the timing of mixing the siloxane mixture, the emulsifier and water, or the siloxane mixture is emulsified by adding the emulsifier and water to obtain a latex (siloxane latex (a)), which is made into fine particles. It may be after conversion. Since the particle size of the obtained polyorganosiloxane (A) can be easily controlled, it is preferable to atomize the siloxane latex (a) and then mix the siloxane latex (a) with the acid catalyst. In particular, it is preferable to drop the finely divided siloxane latex (a) into the acid catalyst aqueous solution at a constant rate.
When the acid catalyst is mixed at the timing of mixing the siloxane mixture, the emulsifier, and water, it is preferable to mix them and then atomize them into fine particles.

The siloxane latex (a) can be made into fine particles by using, for example, a homomixer that makes fine particles by a shearing force due to high-speed rotation, a homogenizer that makes fine particles by the jet output of a high-pressure generator, or the like.
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 (a) and the acid catalyst include mixing by high-speed stirring and mixing by a high-pressure emulsifying device such as a homogenizer. Can be mentioned. Above all, the method using a homogenizer is preferable because the distribution of the particle size of the polyorganosiloxane (A) can be reduced.

The polymerization temperature is preferably 50 ° C. or higher, preferably 80 ° C. or higher.
When the finely divided siloxane latex (a) is dropped into the acid catalyst aqueous solution, the temperature of the acid catalyst aqueous solution is preferably 50 ° C. or higher, preferably 80 ° C. or higher.

When the acid catalyst is mixed at the timing of mixing the siloxane mixture, the emulsifier and water, the polymerization time is preferably 2 hours or more, more preferably 5 hours or more. On the other hand, when the finely divided siloxane latex (a) and the acid catalyst are mixed, it is preferable to drop the finely divided siloxane latex (a) into the acid catalyst aqueous solution and hold it for about 1 hour.

To stop the polymerization, after cooling the reaction solution, neutralize the reaction solution with an alkaline substance such as sodium hydroxide, potassium hydroxide, or sodium carbonate so that the pH of the reaction solution at 25 ° C. becomes about 6 to 8. Can be done by.

The average particle size of the polyorganosiloxane (A) 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 aqueous acid catalyst solution), the polymerization temperature, and the like. For example, the average particle size tends to increase as the amount of the acid catalyst used decreases, and the average particle size tends to decrease as the polymerization temperature increases.

<Alkyl (meth) acrylate-based polymer (B)>
The alkyl (meth) acrylate-based polymer (B) constituting the composite rubber-like polymer (C) is obtained by polymerizing a monomer component containing one or more alkyl (meth) acrylate monomers. .. This monomer component may contain a monomer (other monomer) other than the alkyl (meth) acrylate monomer.

Examples of the alkyl (meth) acrylate monomer include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate; hexyl methacrylate and methacrylic acid. Examples thereof include methacrylic acid alkyl esters such as 2-ethylhexyl and n-lauryl methacrylate. These alkyl (meth) acrylate monomers may be used alone or in combination of two or more. Of these, n-butyl acrylate is preferable because the impact resistance of the molded product is further improved.
The ratio of the alkyl (meth) acrylate monomer in 100% by mass of the monomer component is preferably 80 to 100% by mass, more preferably 90 to 100% by mass. When the ratio of the alkyl (meth) acrylate monomer in 100% by mass of the monomer component is in the above range, the impact resistance of the molded product is further improved.

The other monomer is not particularly limited as long as it can be copolymerized with an alkyl (meth) acrylate monomer, but is not particularly limited, but is an aromatic vinyl compound (for example, styrene, α-methylstyrene, p-methylstyrene, etc.), cyanide. Examples thereof include vinyl chemical compounds (for example, acrylonitrile, methacrylonitrile, etc.). These other monomers may be used alone or in combination of two or more.

The method for producing the alkyl (meth) acrylate-based polymer (B) is not particularly limited, and it can be carried out according to a known method.

<Composite rubber-like polymer (C)>
The composite rubber-like polymer (C) is a composite rubber in which a polyorganosiloxane (A) and an alkyl (meth) acrylate-based polymer (B) are composited.

The average particle size of the composite rubber-like polymer (C) is not particularly limited, but is preferably 0.1 to 1 μm, more preferably 0.2 to 0.5 μm. When the average particle size is within the above range, the impact resistance of the molded product is further improved.
The average particle size of the composite rubber-like polymer (C) can be calculated from the obtained particle size distribution by measuring the volume-based particle size distribution using a particle size distribution measuring device.

(Method for producing composite rubber-like polymer (C))
The method for producing the composite rubber-like polymer (C) is not particularly limited, but a method for heteroaggregating or co-enhancing a plurality of latex containing each of the polyorganosiloxane (A) and the alkyl (meth) acrylate-based polymer (B). In the presence of latex containing either polyorganosiloxane (A) or alkyl (meth) acrylate-based polymer (B), the monomer components forming the other polymer are polymerized and complexed. The method etc. can be mentioned.
In particular, since the volume average particle size of the composite rubber-like polymer (C) can be easily adjusted to be within the above range, a single amount of alkyl (meth) acrylate is present in the presence of the latex-like polyorganosiloxane (A). A copolymer latex is obtained by radically polymerizing a monomer component containing one or more bodies (radical polymerization step), and then the copolymer latex and the acid group-containing copolymer latex are mixed to obtain a copolymer latex. A method of enlarging the polymer latex (enlargement step) is preferable. Further, it is preferable to add a condensate to the copolymer latex before mixing the copolymer latex and the acid group-containing copolymer latex.

Radical polymerization step:
The radical polymerization step is a step of radically polymerizing a monomer component containing one or more alkyl (meth) acrylate monomers in the presence of latex-like polyorganosiloxane (A).
The monomer component containing one or more alkyl (meth) acrylate monomers may be added collectively to the latex-like polyorganosiloxane (A), or may be added continuously or intermittently. May be good.

When radically polymerizing a monomer component containing one or more alkyl (meth) acrylate monomers, a graft cross-linking agent or a cross-linking agent may be used, if necessary.
Examples of the graft cross-linking agent and cross-linking agent include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, and 1,3-butylene glycol diester. , Dimethacrylic acid 1,4-butylene glycol diester and the like. These may be used alone or in combination of two or more.

A radical polymerization initiator and an emulsifier are usually used for radical polymerization.
Examples of the radical polymerization initiator include peroxides, azo-based initiators, and redox-based initiators in which an oxidizing agent and a reducing agent are combined. Among these, a redox-based initiator is preferable, and a sulfoxylate-based initiator in which ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, sodium formaldehyde sulfoxylate, and hydroperoxide are combined is particularly preferable.

The emulsifier is not particularly limited, but various carboxylic acids such as sodium sarcosate, potassium fatty acid, sodium fatty acid, dipotassium alkenyl succinate, and soap loginate can be obtained because the latex has excellent stability during radical polymerization and the polymerization rate can be increased. Salt is preferred. Among these, dipotassium alkenyl succinate is preferable because gas generation can be suppressed when the obtained graft copolymer (E) and the thermoplastic resin composition containing the same are molded at a high temperature.

The ratio of the polyorganosiloxane (A) to the alkyl (meth) acrylate-based polymer (B) in the composite rubber-like polymer (C) is not particularly limited, but the molded product has better impact resistance and surface appearance. Therefore, when the total of the polyorganosiloxane (A) and the alkyl (meth) acrylate-based polymer (B) is 100% by mass, the proportion of the polyorganosiloxane (A) is 2 to 14% by mass. It is preferable to have.

Enlargement process:
The bloating step is a step of bloating the copolymer latex by mixing the copolymer latex obtained in the radical polymerization step with the acid group-containing copolymer latex. The acid group-containing copolymer latex used for bloating contains an acid group-containing monomer, an alkyl (meth) acrylate monomer, and, if necessary, other monomers copolymerizable with these in water. It is a latex of an acid group-containing copolymer obtained by polymerizing a monomer component containing it.

As the acid group-containing monomer, an unsaturated compound having a carboxy group is preferable, and examples of the compound include (meth) acrylic acid, itaconic acid, crotonic acid and the like, and (meth) acrylic acid is particularly preferable. The acid group-containing monomer may be used alone or in combination of two or more.

Examples of the alkyl (meth) acrylate monomer include an ester of acrylic acid and / or methacrylic acid and an alcohol having a linear or branched alkyl group having 1 to 12 carbon atoms, and examples thereof include methyl acrylate and acrylic. Ethyl acetate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate , T-Butyl methacrylate, 2-ethylhexyl methacrylate and the like, and alkyl (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is particularly preferable. The alkyl (meth) acrylate monomer may be used alone or in combination of two or more.

The other monomer is a monomer copolymerizable with the acid group-containing monomer and the alkyl (meth) acrylate monomer, and other than the acid group-containing monomer and the alkyl (meth) acrylate monomer. It is a monomer of. Other monomers include aromatic vinyl compounds (eg, styrene, α-methylstyrene, p-methylstyrene, etc.), vinyl cyanide compounds (eg, acrylonitrile, methacrylicnitrile, etc.), and two or more polymerizable compounds. Examples thereof include compounds having a functional group (for example, allyl methacrylate, polyethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimeritate, etc.). The other monomers may be used alone or in combination of two or more.

The amount of these monomers used is such that the acid group-containing monomer unit is 5 to 40% by mass as a ratio of the solid content of the acid group-containing copolymer latex in 100% by mass, and the alkyl (meth) acrylate is used. The amount of the monomer unit is 60 to 95% by mass, the amount of other monomer units is 0 to 48% by mass, and the amount of the acid group-containing monomer unit is 8 to 30% by mass, alkyl. More preferably, the amount of the (meth) acrylate monomer unit is 70 to 92% by mass, and the amount of the other monomer unit is 0 to 30% by mass. When the proportion of the acid group-containing monomer unit is 5% by mass or more and the proportion of the alkyl (meth) acrylate monomer unit is 95% by mass or less, sufficient bloating ability can be obtained. Further, when the ratio of the acid group-containing monomer unit is 40% by mass or less and the ratio of the alkyl (meth) acrylate monomer unit is 60% by mass or more, a large amount is used in the production of the acid group-containing copolymer latex. The formation of agglomerates can be suppressed. Further, when the other monomer unit is 48% by mass or less, the obtained acid group-containing copolymer latex can have a sufficient bloating ability.

The acid group-containing copolymer latex can be produced by a general emulsion polymerization method.
Examples of emulsifiers used in emulsification polymerization include carboxylic acid-based emulsifiers such as oleic acid, palmitic acid, stearic acid, alkali metal salts of logonic acid, and alkali metal salts of alkenyl succinic acid; alkyl sulfates and alkylbenzene sulfones. Known emulsifiers include anionic emulsifiers selected from sodium acid, sodium alkylsulfosuccinate, sodium polyoxyethylene nonylphenyl ether sulfate and the like. These emulsifiers may be used alone or in combination of two or more.

As a method of using the emulsifier, the whole amount may be added all at once at the initial stage of polymerization, or may be added continuously or intermittently. Depending on the amount of emulsifier and the method of use thereof, the particle size of the acid group-containing copolymer latex may affect the particle size of the composite rubber-like polymer (C) latex having an enlarged particle size. It is preferable to select an appropriate amount and usage method.

As the polymerization initiator used for emulsion polymerization, a thermal decomposition type initiator, a redox type initiator and the like can be used. Examples of the thermal decomposition type initiator include potassium persulfate, sodium persulfate, ammonium persulfate and the like, and examples of the redox type initiator include organic peroxides typified by cumene hydroperoxide-sodium formaldehyde sulfoxylate-iron. A combination of salts and the like is exemplified. These polymerization initiators may be used alone or in combination of two or more.

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

The amount of the acid group-containing copolymer latex added (in terms of solid content) in the bloating step may be adjusted so that the volume average particle size of the composite rubber-like polymer (C) is within the above range. Usually, 0.1 to 5 parts by volume is preferable, and 0.3 to 3 parts by volume is more preferable with respect to 100 parts by volume of the solid content of the copolymer latex obtained in the radical polymerization step. When the amount of the acid group-containing copolymer latex added is 0.1 parts by mass or more, bloating proceeds sufficiently. In addition, it is possible to suppress the generation of a large amount of agglomerates. On the other hand, when the amount of the acid group-containing copolymer latex added is 5 parts by mass or less, it is possible to suppress a decrease in the pH of the bloated latex, and the latex is less likely to become unstable.
The acid group-containing copolymer latex may be added collectively to the copolymer latex, or may be added continuously or intermittently by dropping.

It is more preferable to add a condensing salt salt to the copolymer latex prior to the bloating step. If the condensing acid salt is added to the copolymer latex before the acid group-containing copolymer latex is added, the amount of the acid group-containing copolymer latex added can be reduced because the enlargement is likely to proceed. This makes it possible to easily adjust the volume average particle size and particle size distribution of the composite rubber-like polymer (C) within the above-mentioned ranges.

As the condensing acid salt, for example, a salt of a condensing acid such as phosphoric acid or silicic acid and an alkali metal and / or alkaline earth metal is used. Among these, pyrophosphate, which is a condensing acid of phosphoric acid, and a salt of an alkali metal are preferable, and sodium pyrophosphate or potassium pyrophosphate is particularly preferable.

The amount of the condensing salt added may be adjusted so that the volume average particle size and the particle size distribution of the composite rubber-like polymer (C) are within the above-mentioned ranges, but it is usually obtained by a radical polymerization step. The solid content of the copolymer latex is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 3 parts by mass with respect to 100 parts by mass. If the amount of the condensing salt added is 0.1 parts by mass or more, the enlargement proceeds sufficiently, and if it is 5 parts by mass or less, the enlargement progresses sufficiently, or the rubber latex is easily stabilized and a large amount of coagulation occurs. It is possible to suppress the generation of lumps.
The condensate is preferably added collectively to the copolymer latex.

The pH of the mixture of the copolymer latex and the condensate at 25 ° C. is preferably 7 or more and 10 or less. If the pH is 7 or more and 10 or less, hypertrophy is likely to proceed sufficiently. In order to make the pH 7 or more, general alkaline compounds such as sodium hydroxide and potassium hydroxide can be used.

It is preferable to control the stirring at the time of bloating appropriately. If the stirring is insufficient, the unenlarged rubber-like polymer may remain due to the local progress of hypertrophy. On the other hand, excessive stirring may cause the bloated latex to become unstable and generate a large amount of agglomerates. The temperature at the time of bloating is not particularly limited, but is preferably 20 to 90 ° C, more preferably 30 to 80 ° C. If the temperature is outside this range, bloat may not progress sufficiently.

The composite rubber-like polymer (C) is enlarged by using the acid group-containing copolymer latex as described above, and then further contains a monomer component containing one or more alkyl (meth) acrylate monomers. It may be produced by adding and polymerizing.

The graft copolymer (E) has a form in which the vinyl-based polymer (D) obtained by polymerizing various vinyl-based monomers is grafted onto the composite rubber-like polymer (C). There is.
The vinyl-based monomer is not particularly limited, and examples thereof include aromatic vinyl compounds, (meth) acrylic acid alkyl esters, and vinyl cyanide compounds.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene and the like.
Examples of the (meth) acrylic acid alkyl ester include methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, and t-butyl acrylate. Can be mentioned.
Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.
One of these vinyl-based monomers may be used alone, or two or more thereof may be used in combination.
Among the vinyl-based monomers described above, it is preferable to use styrene and acrylonitrile in combination because the impact resistance of the molded product is further improved.

The graft copolymer (E) is obtained by graft-polymerizing a vinyl-based polymer (D) on a composite rubber-like polymer (C).
The method for performing graft polymerization is not particularly limited, but emulsion polymerization is preferable because the reaction can be controlled so as to proceed stably. Specifically, a method in which vinyl-based monomers are collectively charged into the composite rubber-like polymer (C) and then polymerized; a part of the vinyl-based monomers is first added to the composite rubber-like polymer (C). A method of charging and dropping the rest to the polymerization system while polymerizing at any time; a method of dropping the entire amount of the vinyl-based monomer onto the composite rubber-like polymer (C) and polymerizing at any time can be mentioned. It can be divided into steps or more. It is also possible to change the type and composition ratio of the vinyl-based monomer in each stage.

The mass ratio of the composite rubber-like polymer (C) to the vinyl-based polymer (D) is not particularly limited, but the composite rubber-like polymer (C) is 10 to 80% by mass, and the vinyl-based polymer (D) is 20 to 20 to 80% by mass. It is preferably 90% by mass, more preferably 30 to 70% by mass of the composite rubber-like polymer (C) and 30 to 70% by mass of the vinyl-based polymer (D) (however, the composite rubber-like weight). The total of the coalescence (C) and the vinyl polymer (D) is 100% by mass.). When graft polymerization is carried out at such a mass ratio, the impact resistance of the molded product tends to be more excellent.

A radical polymerization initiator and an emulsifier are usually used for the graft polymerization.
Examples of the radical polymerization initiator include peroxides, azo-based initiators, and redox-based initiators in which an oxidizing agent and a reducing agent are combined. Among these, a redox-based initiator is preferable, and a sulfoxylate-based initiator in which ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, sodium formaldehyde sulfoxylate, and hydroperoxide are combined is particularly preferable.
Further, when performing radical polymerization, various known chain transfer agents may be added in order to control the molecular weight and the graft ratio of the obtained graft copolymer (E).

The emulsifier is not particularly limited, but various carboxylic acids such as sodium sarcosate, potassium fatty acid, sodium fatty acid, dipotassium alkenyl succinate, and soap loginate can be obtained because the latex has excellent stability during radical polymerization and the polymerization rate can be increased. Examples include salt. Among these, dipotassium alkenyl succinate is preferable because it can suppress the generation of gas when the obtained graft copolymer (E) and the thermoplastic resin composition containing the same are molded at a high temperature.

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

Examples of the coagulant used in the wet method include inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid and nitric acid; and metal salts such as calcium chloride, calcium acetate and aluminum sulfate, which are selected according to the emulsifier used in the polymerization. .. For example, when only a carboxylic acid soap such as a fatty acid soap or a rosin acid soap is used as an emulsifier, one or more of the above-mentioned coagulants can be used. Further, when an emulsifier that exhibits 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.

When the wet method is used, a slurry-like graft copolymer (E) can be obtained. As a method for obtaining the dried graft copolymer (E) from the slurry-like graft copolymer (E), first, the remaining emulsifier residue is eluted in water and washed, and then the slurry is centrifuged or pressed. A method of dehydrating with a dehydrator or the like and then drying with an air flow dryer or the like; a method of simultaneously performing dehydration and drying with a squeezing dehydrator or an extruder can be mentioned. By such a method, a powder or particulate dry graft copolymer (E) is obtained.

The cleaning conditions are not particularly limited, but it is preferable to perform cleaning under conditions in which the amount of emulsifier residue contained in 100% by mass of the dried graft copolymer (E) is in the range of 0.5 to 2% by mass. When the emulsifier residue in the graft copolymer (E) is 0.5% by mass or more, the fluidity of the obtained graft copolymer (E) and the thermoplastic resin composition containing the same tends to be further improved. .. On the other hand, when the emulsifier residue in the graft copolymer (E) is 2% by mass or less, the generation of gas can be suppressed when the thermoplastic resin composition is molded at a high temperature.
The graft copolymer (E) discharged from the extrusion dehydrator or extruder may not be recovered and may be directly sent to an extruder or molding machine for producing a thermoplastic resin composition to form a molded product.

(Other resins)
The thermoplastic resin composition may contain only the above-mentioned graft copolymer (E), but from the viewpoint of the moldability of the obtained thermoplastic resin composition and the molded appearance of the molded product, the graft copolymer ( It is preferable to further contain a thermoplastic resin other than E) (another thermoplastic resin (F)).

The other thermoplastic resin (F) is not particularly limited, and for example, an acrylonitrile-styrene copolymer (AS resin), an acrylonitrile-α-methylstyrene copolymer (αSAN resin), a styrene-maleic anhydride copolymer, and the like. Acrylonitrile-styrene-N-substituted maleimide ternary copolymer, styrene-maleic anhydride-N-substituted maleimide ternary copolymer, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene-alkyl (meth) ) Acrylic copolymer (ASA resin), acrylonitrile-ethylene-propylene-diene-styrene copolymer (AES resin), polymethylmethacrylate, polycarbonate resin, polybutylene terephthalate (PBT resin), polyethylene terephthalate (PET resin), Polypolymers such as polyvinyl chloride, polyethylene and polypropylene, styrene-based elastomers such as styrene-butadiene-styrene (SBS), styrene-butadiene (SBR), hydrogenated SBS, styrene-isoprene-styrene (SIS), various olefin-based elastomers, Various polyester-based 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, Examples thereof include PPS resin, PES resin, PEEK resin, polyarylate, liquid crystal polyester resin, and polyamide resin (nylon).
As these other thermoplastic resins (F), one type may be used alone, or two or more types may be used in combination.

The content of the graft copolymer (E) in the thermoplastic resin composition is preferably 20 to 60% by mass, and the content of the other thermoplastic resin (F) is 40 to 80% by mass (however, the graft). The total of the copolymer (E) and the other thermoplastic resin (F) is 100% by mass.). When the content of the graft copolymer (E) is 20% by mass or more (the content of the other thermoplastic resin (F) is 80% by mass or less), the impact resistance of the molded product is further enhanced. On the other hand, if the content of the graft copolymer (E) is 60% by mass or less (the content of the other thermoplastic resin (F) is 40% by mass or more), the thermoplastic resin composition has sufficient moldability. Have.

<Arbitrary ingredient>
In addition to the above-mentioned graft copolymer (E) and other thermoplastic resin (F), the thermoplastic resin composition of the present invention can be used as necessary within a range that does not impair light absorption and reflectivity. It may contain an arbitrary component.
Examples of optional components include various stabilizers such as antioxidants and light stabilizers, and additives such as lubricants, plasticizers, mold release agents, dyes, pigments, antistatic agents, flame retardants, metal powders, and inorganic fillers. Be done.

<Manufacturing method>
The thermoplastic resin composition is obtained by mixing and dispersing the graft copolymer (E), another thermoplastic resin (F) if necessary, and an optional component with a V-type blender, a Henschel mixer, or the like. The mixture is produced by melt-kneading the mixture using a melt-kneader such as a screw extruder, a Banbury mixer, a pressure kneader, or a mixing roll. Further, if necessary, the melt-kneaded product may be pelletized using a pelletizer or the like.

<Average value of light reflectance from 380 nm to 780 nm (visible% R)>
The thermoplastic resin composition of the present invention needs to have an average value (visible% R) of light reflectance in the wavelength range of 380 nm to 780 nm of 5% to 10%. Here, the light reflectance is a measured value for a test piece obtained by molding a thermoplastic resin composition to a thickness of 2 mm. When the light reflectance is 10% or less, the amount of light reflected in the visible light region is small, and the color tone of the molded product is preferable.

<Average value of light absorption rate from 780 nm to 1180 nm (near infrared% A)>
The thermoplastic resin composition of the present invention needs to have an average value (near infrared% A) of light absorption in the wavelength range of 780 nm to 1180 nm of 25% to 93%. Here, the light absorption rate (% A) is calculated by the following equation (1) using the measured values of the light reflectance (% R) and the light transmittance (% T). The light reflectance is a measured value for a test piece obtained by molding a thermoplastic resin composition to a thickness of 2 mm. The light transmittance is a measured value for a test piece obtained by molding a thermoplastic resin composition to a thickness of 0.1 mm. When the light absorption rate is 93% or less, the amount of light absorbed in the near infrared region does not become excessive, and when the molded product is used as an absorbent material and the absorbent material and the transmissive material are laser welded, the color is burnt or discolored. Is not generated, and it is possible to prevent the welded appearance from being deteriorated. When the light absorption rate is 25% or more, the amount of light absorbed in the near infrared region increases, so that sufficient bonding strength can be obtained after laser welding.

Light Absorption Rate (% A) = 100-Light Transmittance (% T) -Light Reflectance (% R) ... (1)

<Ratio of optical characteristics>
The thermoplastic resin composition of the present invention has a ratio (near infrared% A / visible% R) of the average value of the light reflectance in the near infrared region and the average value of the light reflectance in the visible light region. It is preferably 5 to 4.5, and more preferably 10.0 to 5.0. When it is 16.5 or less, the absorption of light in the near infrared region is controlled, and the charring and discoloration of the appearance after laser welding tends to be further suppressed. On the other hand, when it is 4.5 or more, it becomes easy to obtain sufficient bonding strength after laser welding, and the color tone of the molded product tends to be more excellent.

<Effect>
The thermoplastic resin composition of the present invention described above contains the graft copolymer (E), and the light reflectance in the visible light region and the light absorption rate in the near infrared light region of the test piece have specific numerical values. Therefore, it is possible to obtain a molded product having excellent color tone and appearance after laser welding, and having sufficient impact resistance and weather resistance as a resin member.

The thermoplastic resin composition of the present invention is excellent in color tone when formed into a molded product, is capable of suppressing scorching and discoloration of the appearance after laser welding, and can exhibit sufficient bonding strength, and is a resin member. It has sufficient impact resistance and weather resistance. Therefore, the thermoplastic resin composition of the present invention can obtain molded products suitable for vehicle parts such as lamps, interiors and exteriors, OA equipment and home appliance parts, medical appliances, and various industrial materials.

"Molding"
The molded product of the present invention is obtained by molding the above-mentioned thermoplastic resin composition of the present invention by a known molding method.
Examples of the molding method include an injection molding method, a press molding method, an extrusion molding method, a vacuum forming method, a blow molding method and the like.

The molded product of the present invention has excellent color tone, suppresses charring and discoloration in the appearance after laser welding, can exhibit sufficient bonding strength, and has sufficient impact resistance and weather resistance as a resin member. Has.
Examples of the use of the molded product include vehicle parts such as lamps, interiors and exteriors, OA equipment and home appliances, medical appliances, various industrial materials, and the like, and vehicle lamps are suitable.

The molded product of the present invention can be welded to another molded product by laser welding to form a resin bonded body. When laser welding, the molded product of the present invention is used as an "absorbent material" that absorbs laser light, and other molded products are used as a "transmissive material" that transmits laser light.
The material of the transmitting material is not particularly limited as long as it can transmit laser light, and examples thereof include acrylic resin and polycarbonate resin.
The resin bonded body obtained by the present invention is excellent in appearance because charring and discoloration are suppressed at the bonded portion. Moreover, sufficient bonding strength can be exhibited.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, "%" and "part" in the following examples are based on mass unless otherwise specified.
Various measurement and evaluation methods in the following examples and comparative examples are as follows.

"Measurement / evaluation"
<Measurement of light reflectance (% R)>
Using a 4 ounce injection molding machine (manufactured by Japan Steel Works, Ltd.), the length is 100 mm from the pelletized thermoplastic resin composition under the conditions of a cylinder set temperature of 260 ° C., a mold temperature of 60 ° C., and an injection rate of 20 g / sec. , A plate-shaped test piece (molded product) having a width of 100 mm and a thickness of 2 mm was produced. Next, assuming that the total reflectance of the standard white plate (BaSO4) is 100%, the total reflectance of light having a wavelength of 380 nm to 1180 nm is measured at a wavelength interval of 1 nm using a spectrophotometer (Nippon Kogaku Co., Ltd., “V-770”). Measured at.

<Measurement of light transmittance (% T)>
A film-shaped test piece having a thickness of 0.1 mm was prepared from the pellet-shaped thermoplastic resin composition at a set temperature of 250 ° C. Next, the transmittance of light having a wavelength of 380 nm to 1180 nm was measured at a wavelength interval of 1 nm using a spectrophotometer (manufactured by JASCO Corporation, “V-770”).

<Calculation of light absorption rate (% A)>
Using the measured light reflectance (% R) and light transmittance (% T), the absorption rate of light having a wavelength of 380 nm to 1180 nm was calculated at a wavelength interval of 1 nm according to the formula (1).

<Evaluation of impact resistance>
A test piece (molded article) was prepared from a pellet-shaped thermoplastic resin composition using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., "IS55FP-1.5A") in accordance with ISO 3167. The Charpy impact strength of the obtained test piece was measured in an atmosphere of 23 ° C. in accordance with ISO 179.

<Evaluation of laser welding appearance>
Using a 4 ounce injection molding machine (manufactured by Japan Steel Works, Ltd.), the length is 100 mm and the width is 100 mm from pellet acrylic resin under the conditions of cylinder set temperature 260 ° C, mold temperature 60 ° C, and injection rate 20 g / sec. , A plate-shaped test piece (molded product) having a thickness of 2 mm was prepared, and this was used as a transmission material.
On the other hand, as the absorbent material, a pellet-shaped thermoplastic resin composition of the present invention was used, and a test piece prepared under the same conditions as the acrylic resin was used.
The absorbent material and the transmissive material were superposed, and using a laser resin welding device (manufactured by Fine Devices Co., Ltd.), laser light was irradiated from the transmissive material side under the following conditions to weld the absorbent material to obtain a resin bonded body. The appearance of welding at the joint portion of the obtained resin joint body was visually evaluated.
(Welding conditions)
・ Output: 6W
・ Focus diameter: 3 mm
・ Scanning speed: 5 mm / sec ・ Welding length: 20 mm
・ Pressure: 0.5MPa

<Evaluation of color tone>
The brightness (L value) was measured with a colorimeter using the same test piece used for measuring the light reflectance. The lower the L value, the darker the color and the better the color tone.

<Evaluation of weather resistance>
Using the same test piece used to measure the light reflectance, use the "Sunshine Super Long Life Weather Meter WEL-SUN-DCH Type" manufactured by Suga Test Instruments Co., Ltd. at 63 ° C., cycle conditions; 60 minutes (precipitation). : 12 minutes) exposure for 1000 hours. The degree of discoloration (ΔE) of the molded product before and after exposure for 1000 hours was measured using a colorimeter.

"Manufacturing of polyorganosiloxane"
<Production Example 1: Production of Polyorganosiloxane (A)>
98 parts of octamethylcyclotetrasiloxane and 2 parts of γ-methacryloyloxypropyldimethoxymethylsilane were mixed to obtain 100 parts of a siloxane mixture. An aqueous solution consisting of 0.67 parts of sodium dodecylbenzenesulfonate and 300 parts of ion-exchanged water was added thereto, and the mixture was stirred with a homomixer at 10000 rpm for 2 minutes, and then added to the homogenizer at a pressure of 300 kg / cm ² for 2 minutes. The mixture was passed to obtain a stable premixed organosiloxane latex. Separately, 10 parts of dodecylbenzenesulfonic acid and 90 parts of ion-exchanged water were put into a reactor equipped with a reagent injection container, a cooling tube, a jacket heater and a stirrer, and a 10% dodecylbenzenesulfonic acid aqueous solution ( Acid catalyst aqueous solution) was prepared.
While the acid catalyst aqueous solution was heated to 85 ° C., the premixed organosiloxane latex was added dropwise over 2 hours, the temperature was maintained for 3 hours after the completion of the addition, and then the mixture was cooled to 40 ° C. or lower. The reaction was then neutralized to pH 7.0 with a 10% aqueous sodium hydroxide solution to give a latex of polyorganosiloxane (A).
The obtained latex of polyorganosiloxane (A) was dried at 180 ° C. for 30 minutes to determine the solid content, which was 18.2%. The mass-based average particle size was 30 nm.

"Manufacture of acid group-containing copolymer latex"
<Production Example 2: Production of Acid Group-Containing Copolymer Latex (K)>
200 parts of ion-exchanged water, 2 parts of potassium oleate, 4 parts of sodium dioctyl sulfosuccinate, 0.003 ferrous sulfate heptahydrate in a reactor equipped with a reagent injection container, a cooling tube, a jacket heater and a stirrer. Parts, 0.009 parts of ethylenediaminetetraacetic acid disodium salt and 0.3 parts of sodium formaldehyde sulfoxylate were charged under a nitrogen stream, and the temperature was raised to 60 ° C. From the time when the temperature reached 60 ° C., a mixture consisting of 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 dropping, aging was carried out for another 2 hours while maintaining 60 ° C., and the solid content was 33%, the polymerization conversion rate was 96%, and the volume average particle size of the acid group-containing copolymer was 120 nm. Copolymer latex (K) was obtained.

"Manufacturing of Graft Copolymer (E)"
<Production Example 3: Production of Graft Copolymer (E-1)>
In a reactor equipped with a reagent injection container, a cooling tube, a jacket heater and a stirrer, 2.0 parts of polyorganosiloxane (A) latex in terms of solid content, 0.8 parts of dipotassium alkenyl succinate, and 190 parts of ion-exchanged water was charged and mixed. Next, a mixture consisting of 48.0 parts of n-butyl acrylate, 0.6 parts of allyl methacrylate, 0.1 part of dimethacrylic acid 1,3-butylene glycol diester, and 0.1 part of t-butyl hydroperoxide was added. did. The atmosphere was replaced with nitrogen by passing a nitrogen stream through this reactor, and the internal temperature was raised to 60 ° C. When the internal temperature reaches 60 ° C, from 0.000075 parts of ferrous sulfate heptahydrate, 0.00023 parts of ethylenediaminetetraacetic acid disodium salt, 0.2 parts of sodium formaldehyde sulfoxylate, and 10 parts of ion-exchanged water. An aqueous solution was added to initiate radical polymerization. After the polymerization heat generation was confirmed, the jacket temperature was set to 75 ° C., the polymerization was continued until the polymerization heat generation was no longer confirmed, and this state was maintained for another hour, and the composite rubber was a composite of polyorganosiloxane and polybutylacrylate rubber. Was obtained (radical polymerization step). The volume average particle size of the obtained composite rubber was 90 nm.
After the liquid temperature inside the reactor was lowered to 70 ° C., 0.60 part of a 5% aqueous sodium pyrophosphate solution was added as a solid content. After controlling the internal temperature at 70 ° C., 0.60 part of the acid group-containing copolymer latex (K) was added as a solid content, and the mixture was stirred for 30 minutes and enlarged to obtain the latex of the composite rubber-like polymer (C). Obtained (bloated step).
The volume average particle diameter of the obtained latex-like composite rubber-like polymer (C) was 0.2 μm.

An aqueous solution consisting of 0.001 part of ferrous sulfate heptahydrate, 0.003 part of ethylenediamine tetraacetate disodium salt, 0.3 part of longalit, and 10 part of ion-exchanged water was added to the latex of the obtained composite rubber-like polymer. Added. Next, a mixed solution consisting of 10 parts of acrylonitrile, 30 parts of styrene, and 0.18 parts of t-butyl hydroperoxide was added dropwise over 80 minutes for polymerization. After completion of the dropping, the temperature was maintained at 75 ° C. for 30 minutes, and then a mixture consisting of 2.5 parts of acrylonitrile, 7.5 parts of styrene, 0.05 parts of t-butyl hydroperoxide, and 0.02 parts of n-octyl mercaptan. Was added dropwise over 20 minutes to polymerize. After completion of the dropping, the temperature of 75 ° C. was maintained for 30 minutes, 0.05 part of cumenehydroperoxide was added, the temperature of 75 ° C. was maintained for 30 minutes, and then the mixture was cooled to obtain a composite rubber-like polymer ( Latex of a silicone / acrylic composite rubber-based graft copolymer (E-1) obtained by graft-polymerizing acrylonitrile and styrene in C) was obtained.
Next, 150 parts of a 1% aqueous calcium acetate solution was heated to 60 ° C., and 100 parts of the latex of the graft copolymer (E-1) was gradually added dropwise into the mixture to solidify. Then, the precipitate was separated, dehydrated, washed, and then dried to obtain a graft copolymer (E-1).

<Production Example 4: Production of Graft Copolymer (E-2)>
150 parts of ion-exchanged water, 50 parts of polybutadiene latex (volume average particle diameter 0.2 μm) in terms of solid content, disproportionate rosin in a reactor equipped with a reagent injection container, a cooling tube, a jacket heater and a stirrer. 1 part of potassium acid and 0.03 part of potassium hydroxide were charged, and after heating to 60 ° C., 0.007 part of ferrous sulfate heptahydrate, 0.1 part of sodium pyrophosphate, and 0.3 part of crystalline glucose were added. .. Next, a mixed solution consisting of 15 parts of acrylonitrile, 35 parts of styrene, 0.4 parts of cumene hydroperoxide, and 0.5 parts of t-dodecyl mercaptan was added dropwise over 120 minutes for polymerization. After completion of the dropping, the temperature of 70 ° C. was maintained for 60 minutes, 0.05 part of cumene hydroperoxide was added, the temperature of 70 ° C. was maintained for 30 minutes, and then the mixture was cooled to add acrylonitrile and styrene to polybutadiene. Was graft-polymerized to obtain a latex of a polybutadiene-based graft copolymer (E-2).
Next, an antioxidant was added to the latex, 150 parts of a 1% aqueous sulfuric acid solution was heated to 60 ° C., and 100 parts of the latex of the graft copolymer (E-2) was gradually added dropwise into the latex to solidify. Then, the precipitate was separated, dehydrated, washed, and then dried to obtain a graft copolymer (E-2).

"Manufacturing of other thermoplastic resins (F)"
<Manufacturing Example 5: Production of Another Thermoplastic Resin (F-1)>
27 parts of acrylonitrile and 73 parts of styrene were polymerized by a known suspension polymerization to obtain an acrylonitrile-styrene copolymer having a reduced viscosity of 0.61 dl / g measured at 25 ° C. from an N, N-dimethylformamide solution. This was used as another thermoplastic resin (F-1).

<Manufacturing Example 6: Production of Another Thermoplastic Resin (F-2)>
Acrylonitrile-styrene having a reduced viscosity of 0.65 dl / g measured at 25 ° C. from an N, N-dimethylformamide solution obtained by polymerizing 19 parts of acrylonitrile, 53 parts of styrene and 28 parts of N-phenylmaleimide by a known continuous solution polymerization. A −N-phenylmaleimide ternary copolymer was obtained. This was used as another thermoplastic resin (F-2).

<Arbitrary ingredient>
The following pigments were used.
-Carbon black: "# 960" manufactured by Mitsubishi Chemical Corporation
-Iron oxide: "KN-320" manufactured by Toda Kogyo Co., Ltd.
-Titanium oxide: "JR-407" manufactured by TAYCA CORPORATION
The following dyes were used.
-Perinone dye: LANXESS Co., Ltd. "MACROLEX Orange 3G"
-Anthraquinone dye: LANXESS Co., Ltd. "MACROLEX Red Violet R"
-Anthraquinone dye: LANXESS Co., Ltd. "MACROLEX Green 5B"

"Examples 1 to 4, Comparative Examples 1 to 6"
The amounts of the graft copolymer (E), other thermoplastic resin (F), carbon black, titanium oxide, iron oxide, and dye shown in Tables 1 and 2, 1 part of ethylene bisstearylamide, and silicone oil SH200 ( 0.2 parts of Toray Dow Corning Co., Ltd., 0.2 parts of Adecastab AO-60 (manufactured by ADEKA Co., Ltd.), and 0.4 parts of Adecastab LA-57 (manufactured by ADEKA Co., Ltd.) using a Henschel mixer And mixed. A thermoplastic resin pelletized with a pelletizer after melt-kneading the obtained mixture at 250 ° C. using a screw extruder (“TEX-30α twin-screw extruder” manufactured by Japan Steel Works, Ltd.). The composition was obtained.
A test piece (molded product) was prepared using the obtained pelletized thermoplastic resin composition, the light reflectance and light transmittance were measured, the light absorption rate was calculated, and the impact resistance, laser welding appearance, and so on. The color tone and weather resistance were evaluated. These results are shown in Tables 1 and 2.

For near-infrared% A / visible% R in Tables 1 and 2, the average value of the light absorption rate in the near-infrared region is near-infrared% A, and the average value of the light reflectance in the visible light region is visible% R. This is the ratio of near-infrared% A to visible% R.

As shown in Tables 1 and 2, molded products having excellent impact resistance and weather resistance, excellent laser welding appearance, and excellent color tone can be obtained from the thermoplastic resin compositions obtained in each example. It was. Further, in the resin bonded body obtained in each example, the transparent material and the absorbing material were sufficiently bonded.
On the other hand, in the case of each comparative example, the result was inferior to any of the items of impact resistance, weather resistance, laser welding appearance, and color tone of the molded product.
Specifically, in the case of Comparative Example 1, since the visible% R was 10% or more, the color tone was inferior.
In the case of Comparative Example 2, since the near infrared% A was 93% or more, the laser welding appearance was inferior.
In the case of Comparative Example 3, since the near infrared% A was less than 25%, the transmitting material and the absorbing material were not sufficiently bonded.
In the cases of Comparative Examples 4 and 5, the rubber-like polymer contained in the graft copolymer was not a composite rubber-like polymer in which a polyorganosiloxane and an alkyl (meth) acrylate-based polymer were compounded, so that the weather resistance was improved. It was inferior.
In the case of Comparative Example 6, since the graft copolymer was not contained, the impact resistance was inferior.

According to the present invention, it is possible to provide a thermoplastic resin composition which is excellent in color tone and appearance after laser welding and can obtain a molded product having sufficient impact resistance and weather resistance as a resin member. In particular, the balance between the color tone of the molded product and the appearance after laser welding is at a very high level that cannot be obtained with conventionally known thermoplastic resin compositions, and vehicle parts such as lamps, interiors, and exteriors, and OA equipment. It has extremely high utility value as home appliances, medical appliances, and various industrial materials.

Claims (3)

A graft copolymer (E) in which a vinyl-based polymer (D) is grafted onto a composite rubber-like polymer (C) in which a polyorganosiloxane (A) and an alkyl (meth) acrylate-based polymer (B) are composited. A thermoplastic resin composition containing
When the light reflectance (% R) and the light absorption rate (% A) represented by the following formula (1) are measured in the visible light region to the near infrared light region at a wavelength interval of 1 nm,
The average value (visible% R) of the light reflectance from 380 nm to 780 nm is 5% to 10%.
A thermoplastic resin composition satisfying that the average value (near infrared% A) of the light absorption rate from 780 nm to 1180 nm is 25% to 93%.
Light Absorption Rate (% A) = 100-Light Transmittance (% T) -Light Reflectance (% R) ... (1) The feature is that the ratio (near infrared% A / visible% R) of the average value of the light absorption rate in the near infrared region and the average value of the light reflectance in the visible light region is 16.5 to 4.5. The thermoplastic resin composition according to claim 1. A molded product obtained by molding the thermoplastic resin composition according to any one of claims 1 or 2.