JP2017179074A - Thermoplastic resin composition and molded article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition from which a molded article excellent in color tone, molding appearance, weather resistance, impact resistance, and welding appearance can be obtained.SOLUTION: The thermoplastic resin composition contains a thermoplastic resin (A) and carbon black (B). The thermoplastic resin (A) contains a graft copolymer (C) obtained by grafting a vinyl polymer onto a composite rubbery polymer in which a polyorganosiloxane and an alkyl (meth)acrylate polymer are combined. In the carbon black (B), the volume average particle diameter of secondary particles is 200 nm or more, and the ratio of secondary particles having a particle diameter of 800 nm or more to the total of the secondary particles is less than 20 vol.%. The content of the carbon black (B) is 0.1-3.0 pts.mass based on 100 pts.mass of the thermoplastic resin (A).SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic resin composition containing carbon black and a molded article using the same.

With the development of technology, the application fields of resins, such as vehicle parts, home appliance parts, and various industrial materials, have been increasing in recent years, and the required level for molding appearance has also increased.
Secondary processing technology related to resin bonding is also one of the technologies that contribute to the expansion of resin application fields. Examples of resin bonding methods include mechanical bonding with screws and bolts, bonding with an adhesive such as hot melt, hot plate welding by applying heat typified by hot plate welding, and vibrating the bonding portion. Examples include vibration welding using frictional heat generated by this, laser welding using irradiation heat generated by irradiating the joint with laser light, and the like. Recently, hot plate welding, vibration welding, and laser welding have increased their usefulness from the viewpoint of reducing processing steps, reducing weight, reducing environmental impact, etc., and welded parts of resin joints obtained by these methods Improvement of the appearance (welding appearance) of the steel has been a problem.

  In hot plate welding, for example, a heated hot plate is pressed against the surfaces (bonding sites) of the two resin members for several seconds to melt them together, and then quickly pulled away from the hot plate to join them together. . Hot plate welding is widely used. However, in hot plate welding, when the hot plate is pulled away from the bonding part of the resin member, a stringing phenomenon may occur in which the molten resin is stretched into a string shape. When this stringing becomes significant, the resulting resin joined body has a poor appearance.

  In the vibration welding, for example, vibration due to pressure and reciprocating motion is applied to the bonding portions of the two resin members, and the resin component of the bonding portion is melted by the frictional heat to join them. Vibration welding is an excellent method in which resin members do not need to be heated and the resin members can be joined in an extremely short time. However, in this vibration welding, there is a case where a thread burr phenomenon that the melted resin protrudes into a thread shape outside the joint portion may occur. When this thread burr becomes prominent, the resulting resin bonded body has a poor appearance.

  In laser welding, usually, two materials, a “transmitting material” that transmits laser light and an “absorbing material” that absorbs laser light, are joined. For example, if an absorbent material and a transmissive material are placed in contact with their respective bonding sites and laser light is irradiated from the transmissive material side to the material contact interface in a non-contact manner, the irradiated laser light passes through the transmissive material as it is. To reach the absorbent surface and be absorbed. The light energy absorbed on the surface of the absorber is converted into heat and melts the bonding site. Further, the melting heat is transferred to the permeable material, and the bonding portion of the permeable material is melted. Thereafter, the melted bonding parts of the absorbent material and the permeable material are solidified and welded together with cooling. The resin joined body obtained through such a process is excellent in strength, airtightness, and appearance (no occurrence of burrs, etc.). Laser welding also has features such as a favorable working environment and less damage to the built-in components when some components are built in the resin member to be joined. However, in this method, if the laser beam to be irradiated is too strong, the amount of heat generated by the resin increases, which causes poor appearance such as foaming, scoring, and discoloration. On the other hand, when the laser beam to be irradiated is too weak, the bonding strength is lowered, and in some cases, a problem such as insufficient welding may occur. For this reason, when performing laser welding, it is very important to control the heat generation amount of the resin within an appropriate range.

By the way, a molded product obtained from a thermoplastic resin is often used in a state colored with a pigment (colored molded product). From the viewpoint of product design, the color tone of colored molded products is very important. Although the importance of color tone is also high in vehicle parts and the like, the demand for black color tends to increase year by year because the design is preferred in the market.
Since carbon black, which is a typical black colorant, has high laser light absorbability, it is efficient in increasing the amount of heat generated and melting the resin.
However, if the amount of carbon black added is excessively large, the amount of heat generation becomes excessive, and as described above, appearance defects such as foaming, scoring, and discoloration are likely to be caused when irradiated with laser light. In other words, if the amount of carbon black added is increased in order to produce a deep black, the appearance after laser welding is adversely affected. Therefore, it is very difficult to achieve both the color tone (particularly black) and the appearance after laser welding.

Patent Document 1 contains a styrene-based resin and a colorant as a colored styrene-based resin molded body excellent in laser marking properties and molded product appearance (surface gloss). The molded body has a secondary content of 0.1 to 10 μm. The number of colorants present in the particles is disclosed to be 100 to 20000 / m ² .
However, in this document, there is no description regarding making the color tone (particularly blackness) of the molded article compatible with the appearance after laser welding. The colored styrene-based resin molded article disclosed in Patent Document 1 has a technical problem in terms of the balance between blackness and absorption of laser light and impact resistance as a laser welding material.

Patent Document 2 discloses a rubber-reinforced copolymer resin (with a gel content of 70) in order to improve a defective phenomenon that occurs during vibration welding, hot plate welding, or laser welding in joining the lamp housing to another member. % Or more obtained by polymerizing a vinyl monomer containing an aromatic vinyl compound and a vinyl cyanide compound in the presence of a rubbery polymer) or the rubber-reinforced copolymer resin and a vinyl monomer A rubber-reinforced resin comprising a composition with a (co) polymer, and a copolymer containing a maleimide monomer unit and / or a (co) polymer of α-methylstyrene were combined at a specific ratio. A thermoplastic resin composition for a lamp housing is disclosed.
However, in this document, there is no description regarding making the color tone (particularly blackness) of the molded article compatible with the appearance after laser welding. The composition disclosed in Patent Document 2 cannot sufficiently satisfy the required level for blackness.

JP 2000-309039 A JP 2004-182835 A

An object of the present invention is to provide a thermoplastic resin composition from which a molded product excellent in color tone, molded appearance, weather resistance, impact resistance and weld appearance can be obtained.
Another object of the present invention is to provide a molded article excellent in color tone, molded appearance, weather resistance, impact resistance and weld appearance.

As a result of intensive studies, the present inventors have determined that a thermoplastic resin composition includes a graft copolymer obtained by grafting a vinyl polymer to a composite rubber-like polymer in which a polyorganosiloxane and an alkyl (meth) acrylate polymer are combined. The present inventors have found that the above problems can be solved by blending carbon black having a specific secondary particle size distribution into the product, and have reached the present invention.
That is, this invention makes the following a summary.

[1] containing a thermoplastic resin (A) and carbon black (B),
The thermoplastic resin (A) contains a graft copolymer (C) obtained by grafting a vinyl polymer to a composite rubber-like polymer in which a polyorganosiloxane and an alkyl (meth) acrylate polymer are combined.
In the carbon black (B), the volume average particle diameter of secondary particles is 200 nm or more, and the ratio of secondary particles having a particle diameter of 800 nm or more to the whole secondary particles is less than 20% by volume,
Content of the said carbon black (B) is 0.1-3.0 mass parts with respect to 100 mass parts of said thermoplastic resins (A), The thermoplastic resin composition characterized by the above-mentioned.
[2] In the volume-based particle size distribution of the carbon black (B), the particle size at which the cumulative value is 10% is 10% cumulative particle size (d10), and the particle size at which the cumulative value is 50% is 50% cumulative. When the particle diameter (d50) and the particle diameter at which the cumulative value becomes 90% is 90% cumulative particle diameter (d90), M obtained by the following expression (1) satisfies the following expression (2), [1 ] Of the thermoplastic resin composition.
M = (d90−d10) / d50 (1)
1.5 ≦ M ≦ 2.5 (2)
[3] A molded article using the thermoplastic resin composition of [1] or [2].

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

Hereinafter, the present invention will be described in detail.
In the following description, the “molded product” is formed by molding the thermoplastic resin composition of the present invention. Moreover, in the following description, unless otherwise specified, “excellent color tone” means that the blackness of the molded product is deep (dark). “Excellent molding appearance” means that the molded article has high glitter. “The weld appearance is excellent” means that after the molded product is welded by laser welding, vibration welding or hot plate welding, there is no appearance defect in the welded portion. In the case of laser welding, the appearance defect means charring, discoloration, and insufficient welding in the welded part, in the case of vibration welding, it means thread burr in the welded part, and in the case of hot plate welding, the thread in the welded part. It means pulling. The “unit” in the polymer indicates a structural unit (monomer unit) constituting the polymer.

"Thermoplastic resin composition"
The thermoplastic resin composition of the present invention contains a thermoplastic resin (A) and carbon black (B).
The thermoplastic resin (A) contains the graft copolymer (C). The graft copolymer (C) is a composite rubber-like polymer grafted with a vinyl polymer, and the composite rubber-like polymer is a composite of a polyorganosiloxane and an alkyl (meth) acrylate polymer. It is a thing.
The thermoplastic resin (A) can further contain a thermoplastic resin (D) other than the graft copolymer (C).
The thermoplastic resin composition of the present invention contains other additives in addition to the thermoplastic resin (A) and carbon black (B), as required, within a range where the effects of the present invention are not significantly impaired. May be.

<Polyorganosiloxane>
The polyorganosiloxane constituting the composite rubber-like polymer is not particularly limited, but a polyorganosiloxane containing a vinyl polymerizable functional group (vinyl polymerizable functional group-containing polyorganosiloxane) is preferable, and a vinyl polymerizable functional group containing A polyorganosiloxane having a siloxane unit and a dimethylsiloxane unit is more preferred.

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 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 considering the reactivity with dimethylsiloxane, An alkoxysilane compound containing a vinyl polymerizable functional group is preferred. Specifically, β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylethoxydiethylsilane, and methacryloyloxysiloxanes such as γ-methacryloyloxypropyldiethoxymethylsilane and δ-methacryloyloxybutyldiethoxymethylsilane; vinylsiloxanes such as tetramethyltetravinylcyclotetrasiloxane and p-vinylphenyldimethoxymethylsilane;

The number of vinyl polymerizable functional group-containing siloxane units possessed by the polyorganosiloxane may be one, or two or more.
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.

  In the polyorganosiloxane, the content of silicon atoms having three or more siloxane bonds 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 3 or more siloxane bonds is 1 mol% or less, the surface appearance of the molded article is further improved.

  As a preferred embodiment of the polyorganosiloxane, 0.3 to 3 mol% of a vinyl polymerizable functional group-containing siloxane unit and 99.7 to 97 mol% of a dimethylsiloxane unit (however, a vinyl polymerizable functional group-containing siloxane unit 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 average particle size of the polyorganosiloxane is not particularly limited, but is preferably 400 nm or less because the surface appearance of the molded product becomes even better.
Here, the average particle size of the polyorganosiloxane is a value (mass average particle size) calculated from the particle size distribution obtained by measuring the mass-based particle size distribution using a capillary type particle size distribution analyzer. is there.

(Method for producing polyorganosiloxane)
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. These dimethylsiloxane oligomers may be used alone or in combination of two or more.

The method for polymerizing the siloxane mixture is not particularly limited, but 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. Specific examples 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. If the usage-amount of an emulsifier is 0.05 mass part or more, a dispersion state will be easy to be stabilized and it will become easy to hold | maintain the emulsification state of a fine particle diameter. On the other hand, if the usage-amount of an emulsifier is 5 mass parts or less, 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. 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 in that it is excellent in the stabilizing action 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.
Although the addition amount of an acid catalyst should just be determined suitably, it is about 0.1-20 mass parts normally with respect to 100 mass parts of siloxane mixtures.

The acid catalyst may be mixed with the siloxane mixture, the emulsifier and water at the timing of mixing them, or 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. Since it is easy to control the particle diameter of the resulting 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. . Among them, the method using a homogenizer is preferable because the particle size distribution of the polyorganosiloxane can be reduced.

The polymerization temperature is preferably 50 ° C. or higher, and 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 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. On the other hand, when mixing the microparticulated siloxane latex and the acid catalyst, it is preferable that the entire amount of the microparticulated siloxane latex is dropped into the acid catalyst aqueous solution and then maintained 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 average particle diameter of the polyorganosiloxane can be controlled by adjusting the composition of the siloxane mixture, the amount of acid catalyst used (the content of the acid catalyst in the acid catalyst aqueous 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 polymer>
The alkyl (meth) acrylate polymer constituting the composite rubber-like polymer is a polymer having an alkyl (meth) acrylate monomer unit. The alkyl (meth) acrylate polymer may further have another monomer unit other than the alkyl (meth) acrylate monomer unit.

  Examples of the alkyl (meth) acrylate monomer include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate and 2-ethylhexyl acrylate; hexyl methacrylate and methacrylic acid. Examples include methacrylic acid alkyl esters such as 2-ethylhexyl and n-lauryl methacrylate. These alkyl (meth) acrylates 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 monomer has, 1-8 are more preferable. As the alkyl (meth) acrylate monomer, n-butyl acrylate is particularly preferable in that the impact resistance of the molded product is further improved.

  In the alkyl (meth) acrylate polymer, the content of the alkyl (meth) acrylate monomer 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.

  The other monomer is not particularly limited as long as it is copolymerizable with an alkyl (meth) acrylate monomer. For example, an aromatic vinyl compound (for example, styrene, α-methylstyrene, p-methylstyrene, etc.) , Vinyl cyanide 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. These other monomers 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 monomer.
The polymerization method of the monomer component is not particularly limited, and can be performed according to a known method.

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

  The ratio between the polyorganosiloxane and the alkyl (meth) acrylate polymer in the composite rubber-like polymer is not particularly limited, but the impact resistance and surface appearance of the molded product will be more excellent. When the total with the alkyl (meth) acrylate polymer is 100% by mass, the ratio of the polyorganosiloxane is preferably 2 to 14% by mass.

  The gel content of the composite rubber-like 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 is within this range, the impact resistance of the molded product becomes better.

Specifically, the gel content of the composite rubber-like polymer is measured by the following method.
The weighed composite rubber-like polymer is dissolved in a suitable solvent at room temperature (23 ° C.) for 20 hours, and then centrifuged. The supernatant is removed by decantation, and the remaining insoluble matter is removed at 60 ° C. at 24 ° C. Weigh after drying for hours. The ratio (mass%) of the insoluble matter with respect to the composite rubber-like polymer weighed first is calculated | required, and this ratio is made into gel content of a composite rubber-like polymer. As the solvent used for dissolving the composite rubber-like polymer, for example, toluene or acetone can be used.

The composite rubbery polymer is typically granular.
The average particle size of the composite rubber-like polymer is not particularly limited, but is preferably 100 to 1000 nm, and more preferably 150 to 500 nm.
The 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.

(Production method of composite rubber-like polymer)
The method for producing the composite rubbery polymer is not particularly limited. For example, a method in which a plurality of latexes each containing a polyorganosiloxane and an alkyl (meth) acrylate polymer are hetero-aggregated or co- enlarged; polyorganosiloxane and alkyl Examples thereof include a method in which a monomer component forming the other polymer is polymerized and combined in the presence of a latex containing any one of the (meth) acrylate polymers.

  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. ) A step of radical polymerizing a monomer component containing one or more acrylate monomers to obtain a polymer latex (radical polymerization step), and mixing the polymer latex and the acid group-containing copolymer latex And a method of enlarging the polymer latex (the enlargement step). 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 polymerization of a monomer component containing at least one alkyl (meth) acrylate monomer in the presence of latex polyorganosiloxane.
The monomer component containing at least one alkyl (meth) acrylate monomer may be added all at once to the latex polyorganosiloxane, or may be added continuously or intermittently.

When radically polymerizing a monomer component containing one or more alkyl (meth) acrylate monomers, 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. In these, a redox-type initiator is preferable and especially the sulfoxylate-type initiator which combined ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, sodium formaldehyde sulfoxylate, and hydroperoxide is preferable.

  Although it does not restrict | limit especially as an emulsifier, since it is excellent in the stability of the latex at the time of radical polymerization and a polymerization rate can be raised, various carboxylic acids, such as sodium sarcosinate, fatty acid potassium, fatty acid sodium, alkenyl succinate dipotassium, rosin acid soap, etc. Salts are preferred. Of these, dipotassium alkenyl succinate is preferable because gas generation can be suppressed when the obtained graft copolymer (C) and the thermoplastic resin composition containing the graft copolymer (C) 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. Before mixing with the acid group-containing copolymer latex in the enlargement process, the enlargement easily proceeds 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. Among these, 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 particularly preferable.

The addition amount of the condensed acid salt may be adjusted so that the volume average particle size and particle size distribution of the composite rubber-like polymer are within the above-mentioned ranges. Usually, the polymer latex obtained in the radical polymerization step is used. It is preferable to set it as 0.1-5 mass parts with respect to 100 mass parts of solid content, 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 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, it is possible to prevent the enlargement from proceeding sufficiently or the rubber latex to be stabilized easily and to generate a large amount of agglomerates.
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 the pH is 7 or more, enlargement is likely to proceed sufficiently.
In order to set this pH to 7 or more, general alkali compounds such as sodium hydroxide and potassium hydroxide can be added.

"Hypertrophy process"
The enlargement step is obtained in the radical polymerization step, and if necessary, by mixing the polymer latex to which the condensation salt is added in the condensation salt addition step and the acid group-containing copolymer latex, This is a step of enlarging the polymer latex.

(Acid group-containing copolymer latex)
The acid group-containing copolymer has an acid group-containing monomer unit and an alkyl (meth) acrylate monomer 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 compound include (meth) acrylic acid, itaconic acid, crotonic acid and the like, and (meth) acrylic acid is particularly preferable. An acid group containing monomer may be used individually by 1 type, and may use 2 or more types together.

  The alkyl (meth) acrylate monomer is preferably an alkyl (meth) acrylate having an alkyl group having 1 to 8 carbon atoms, such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, acrylic acid. Examples include isobutyl, 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. It is done. Among these, alkyl (meth) acrylates having a C 1-8 alkyl group are preferred. An alkyl (meth) acrylate monomer may be used individually by 1 type, and may use 2 or more types together.

  Other monomers are monomers copolymerizable with acid group-containing monomers and alkyl (meth) acrylate monomers, and other than acid group-containing monomers and alkyl (meth) acrylate monomers Is a monomer. 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 monomer The proportion of units is preferably 60 to 95 mass%, the proportion of other monomer units is preferably 0 to 35 mass%, the proportion of acid group-containing monomer units is 8 to 30 mass%, alkyl (meth) It is more preferable that the proportion of acrylate monomer units is 70 to 92% by mass and the proportion of other monomer units is 0 to 22% by mass.
If the ratio of the acid group-containing monomer unit is not less than the lower limit of the above range and the ratio of the alkyl (meth) acrylate monomer unit is not more than the upper limit of the above range, sufficient enlargement ability can be obtained.
When the ratio of the acid group-containing monomer unit is not more than the upper limit of the above range and the ratio of the alkyl (meth) acrylate monomer unit is not less than the lower limit of the above range, the acid group-containing copolymer latex is produced. Generation of a large amount of agglomerates can be suppressed.
If the proportion of other monomer units is not more than the upper limit of the above range, the resulting acid group-containing copolymer latex can have a sufficient enlargement ability.

The acid group-containing copolymer latex used for enlargement is composed of an acid group-containing monomer, an alkyl (meth) acrylate monomer, and, if necessary, other monomers copolymerizable with these in water. It can be obtained by polymerizing the monomer component.
The polymerization of the monomer component can be performed by a general emulsion polymerization method.
Emulsion polymerization is usually performed using an emulsifier and a polymerization initiator.

  As the emulsifier used in the emulsion polymerization, known emulsifiers can be used, for example, carboxylic acid-based emulsifiers such as oleic acid, palmitic acid, stearic acid, alkali metal salts of rosin acid, and alkali metal salts of alkenyl succinic acid. Anionic emulsifiers such as sodium alkyl sulfate, sodium alkylbenzene sulfonate, sodium alkyl sulfosuccinate, 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 in the initial stage of polymerization, or may be added continuously or intermittently. Depending on the amount of emulsifier and its method of use, the particle size of the acid group-containing copolymer latex, and hence the particle size of the composite rubber-like polymer latex with an enlarged particle size, may be affected. It is preferable to select a method of use.

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

  In the case of emulsion polymerization, a chain transfer agent such as mercaptans (for example, t-dodecyl mercaptan, n-octyl mercaptan, etc.), terpinolene, α-methylstyrene dimer or the like is used to adjust the molecular weight or the pH is adjusted. Therefore, an electrolyte can be added as an alkali, an acid, or a thickener.

(Polymerized latex)
In the enlargement step, the addition amount of the acid group-containing copolymer latex to the polymer latex (in terms of solid content) is adjusted so that the volume average particle diameter of the resulting 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 equal to or greater than the lower limit of the above range, the enlargement proceeds sufficiently. Moreover, it can suppress that agglomerates generate | occur | produce in large quantities. On the other hand, 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 stirring during enlargement. If the stirring is insufficient, the unexpanded rubbery polymer may remain due to local enlargement. On the other hand, if the stirring is performed excessively, the enlarged latex becomes unstable and a large amount of agglomerates may be generated.
Although the temperature in particular when performing enlargement is not restrict | limited, 20-90 degreeC is preferable and 30-80 degreeC is more preferable. If the temperature is outside this range, the enlargement may not proceed sufficiently.

  The composite rubbery polymer is obtained in the radical polymerization step, and the copolymer latex to which a condensed acid salt is added as necessary is enlarged using the acid group-containing copolymer latex as described above. Then, a monomer component containing at least one alkyl (meth) acrylate monomer may be further added and polymerized.

<Vinyl polymer>
The vinyl polymer constituting the graft copolymer (C) has a vinyl monomer unit.
A vinyl monomer is a monomer having a polymerizable unsaturated double bond. Although it does not restrict | limit especially as a vinyl-type monomer, An aromatic vinyl compound, (meth) acrylic-acid alkylester, a vinyl cyanide compound, etc. are preferable. “(Meth) acrylic acid alkyl ester” is a generic term for acrylic acid alkyl esters and methacrylic acid alkyl esters.
Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, and the like. Examples of (meth) acrylic acid alkyl esters 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. These vinyl monomers can be used alone or in combination of two or more.
Among these, as the vinyl monomer, it is preferable to use styrene and acrylonitrile in combination 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.

<Graft copolymer (C)>
The graft copolymer (C) is obtained by grafting the vinyl polymer on the composite rubber-like polymer.
In the graft copolymer (C), the mass ratio between the composite rubber-like polymer and the vinyl polymer is not particularly limited, but relative to the total mass (100 mass%) of the composite rubber-like polymer and the vinyl polymer. The composite rubbery polymer is preferably 10 to 80% by mass, the vinyl polymer is preferably 20 to 90% by mass, the composite rubbery polymer is 30 to 70% by mass, and the vinyl polymer is 30 to 70% by mass. % Is particularly preferred. When the mass ratio of the composite rubber-like polymer and the vinyl polymer is within the above range, the impact resistance of the molded product becomes more excellent.

(Production method of graft copolymer (C))
The graft copolymer (C) is obtained by grafting a vinyl polymer to a composite rubber-like polymer.
Examples of a method for grafting a vinyl polymer to a composite rubber-like polymer include a method in which a vinyl monomer is polymerized (graft polymerization) in the presence of the composite rubber-like polymer. The graft copolymer (C) thus obtained has a form in which a vinyl polymer obtained by polymerizing a vinyl monomer is grafted to a composite rubber-like polymer.

  The method for carrying out the graft polymerization is not particularly limited, but emulsion polymerization is preferred 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.

  The mass ratio of the rubber-like polymer and the vinyl monomer is not particularly limited, but the composite rubber-like polymer is 10 to 80% by mass with respect to the total mass of the composite rubber-like polymer and the vinyl monomer. The vinyl monomer is preferably 20 to 90% by mass, the composite rubbery polymer is preferably 30 to 70% by mass, and the vinyl monomer is particularly preferably 30 to 70% by mass. When the mass ratio between the composite rubber-like polymer and the vinyl monomer is within the above range, the mass ratio between the composite rubber-like polymer and the vinyl polymer in the graft copolymer (C) is within the above preferred range. It is easy to be inside.

Emulsion polymerization is usually performed using a radical polymerization initiator and an emulsifier. For example, a vinyl monomer is added to a rubber polymer latex containing a rubber 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 resulting graft copolymer (C).
The polymerization conditions for radical polymerization are not particularly limited, and examples 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. Among these, a redox initiator is preferable, and a sulfoxylate 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 is excellent in the stability of latex during radical polymerization and can increase the polymerization rate. Acid salts are preferred. Of these, dipotassium alkenyl succinate is preferable because gas generation can be suppressed when the obtained graft copolymer (C) and the thermoplastic resin composition containing the graft copolymer (C) are molded at high temperature.

The graft copolymer (C) obtained by performing graft polymerization as described above is usually in a latex state.
As a method for recovering the graft copolymer (C) from the latex of the graft copolymer (C), for example, the latex of the graft copolymer (C) is poured into hot water in which a coagulant is dissolved. Examples thereof include a wet method of coagulating in a slurry state; a spray drying method of recovering the graft copolymer (C) semi-directly by spraying the latex of the graft copolymer (C) 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 a carboxylic acid soap such as fatty acid soap or 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.

  When a wet method is used, a slurry-like graft copolymer (C) is obtained. As a method for obtaining the dried graft copolymer (C) from the slurry graft copolymer (C), first, the remaining emulsifier residue is eluted and washed in water, and then the slurry is centrifuged or washed. Examples include a method of dehydrating with a press dehydrator or the like and then drying with an airflow dryer or the like; a method of simultaneously performing dehydration and drying with a press dehydrator or an extruder. By this method, a powder or particulate dry graft copolymer (C) is obtained.

Although it does not restrict | limit especially as washing | cleaning conditions, It is preferable to wash | clean on the conditions from which the amount of emulsifier residues contained in 100 mass% of graft copolymers (C) after drying becomes the range of 0.5-2 mass%. If the emulsifier residue in the graft copolymer (C) is 0.5% by mass or more, the fluidity of the resulting graft copolymer (C) and the thermoplastic resin composition containing the graft copolymer tends to be further improved. . On the other hand, if the emulsifier residue in the graft copolymer (C) is 2% by mass or less, gas generation when the thermoplastic resin composition is molded at high temperature can be suppressed.
In addition, the graft copolymer (C) discharged | emitted from the press dehydrator and the extruder is not collect | recovered, but it is also possible to send directly to the extruder and molding machine which manufacture a resin composition, and to make a molded article.

<Thermoplastic resin (A)>
A thermoplastic resin (A) may be comprised only by the graft copolymer (C), and may further contain other thermoplastic resins (D) other than the graft copolymer (C). In terms of balance between impact resistance and fluidity, the thermoplastic resin (A) preferably contains another thermoplastic resin (D).

  The thermoplastic resin (A) preferably comprises 20 to 100% by mass of the graft copolymer (C) and 0 to 80% by mass of the other thermoplastic resin (D). ) And 60 to 80% by mass of the other thermoplastic resin (D) (more preferably, the graft copolymer (C) and the other thermoplastic resin (D)). The total is 100% by mass). When the content of the graft copolymer (C) in the thermoplastic resin (A) is not less than the lower limit of the above range, the impact resistance and weld appearance of the molded product are more excellent.

<Other thermoplastic resin (D)>
The other thermoplastic resin (D) is not particularly limited. 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 (ASA resin), acrylonitrile-ethylene-propylene-diene-styrene copolymer (AES resin), polymethyl methacrylate, polycarbonate resin, polybutylene terephthalate (PBT resin), polyethylene terephthalate (PET resin) ), Polyolefins such as polyvinyl chloride, polyethylene and polypropylene, styrene elastomers such as styrene-butadiene-styrene (SBS), styrene-butadiene (SBR), hydrogenated SBS, styrene-isoprene-styrene (SIS), and various olefins Elastomer, 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, polyphenylene sulfide (PPS resin), polyether sulfone (PES resin), polyether ether ketone (PEEK resin), polyarylate, liquid crystal polyester Fat, polyamide resin (e.g., nylon), and the like. These other thermoplastic resins (D) may be used alone or in combination of two or more.

<Carbon black (B)>
Examples of carbon black (B) include channel black, furnace black, lamp black, thermal black, ketjen black, and naphthalene black. Any of these may be used alone or in combinations of two or more.

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 any of ozone, nitric acid, nitrous acid, sodium hypochlorite, and hydrogen peroxide. Oxidation treatment generates acidic functional groups such as carboxyl groups and phenolic hydroxyl groups on the carbon black surface, improving the wettability and dispersibility of the carbon black surface.

Carbon black (B) usually exists as secondary particles having a shape in which spherical primary particles are aggregated.
In carbon black (B), the volume average particle diameter of secondary particles is 200 nm or more, and the ratio of secondary particles having a particle diameter of 800 nm or more to the whole secondary particles is less than 20% by volume. If the volume average particle diameter of the secondary particles is less than 200 nm or the ratio of the secondary particles having a particle diameter of 800 nm or more is 20% by volume or more, the color tone and laser weldability may be insufficient.
The upper limit of the volume average particle size of the secondary particles of carbon black (B) is not particularly limited as long as the ratio of the secondary particles having a particle size of 800 nm or more is less than 20% by volume, but is typically 600 nm or less.
The lower limit of the ratio of secondary particles having a particle diameter of 800 nm or more is not particularly limited, and may be 0% by mass.
The volume average particle diameter is measured by a dynamic light scattering method. For example, carbon black (B) is dispersed in a dispersion medium (N-methylpyrrolidone), a volume-based particle size distribution is measured using a nanotrack, and the volume average particle size is calculated from the obtained particle size distribution. .

Carbon black (B) has a 10% cumulative particle diameter (d10) with a cumulative value of 10% in the volume-based particle size distribution of secondary particles, and a 50% particle diameter with the cumulative value of 50%. Cumulative particle diameter (d50), where the particle diameter at which the cumulative value is 90% is 90% cumulative particle diameter (d90), M obtained by the following expression (1) satisfies the following expression (2): Preferably there is.
M = (d90−d10) / d50 (1)
1.5 ≦ M ≦ 2.5 (2)
If M is more than 1.5, the color tone and laser weldability tend to be more excellent. When M is less than 2.5, the color tone tends to be more excellent.
More preferably, M satisfies 1.5 ≦ M ≦ 2.0.
The particle size distribution is measured by a dynamic light scattering method. For example, carbon black (B) is dispersed in a dispersion medium (N-methylpyrrolidone), and the particle size distribution is measured using nanotrack.

Content of carbon black (B) in a thermoplastic resin composition is 0.1-3.0 mass parts with respect to 100 mass parts of thermoplastic resins (A), and 0.3-2.0 mass parts Is preferable, and 0.5 to 1.0 part by mass is more preferable.
If content of carbon black (B) is more than the said lower limit, the color tone of the molded article obtained from a thermoplastic resin composition is excellent. Also, sufficient welding strength can be obtained by laser welding.
When the content of carbon black (B) is not more than the above upper limit value, it is difficult for scorch and discoloration to occur during laser welding, and the weld appearance is excellent. In addition, the appearance of welding tends to be excellent even in vibration welding and hot plate welding.

<Other additives>
Examples of other additives include various stabilizers such as antioxidants and light stabilizers, lubricants, plasticizers, mold release agents, dyes, pigments, antistatic agents, flame retardants, inorganic fillers, metal powders, and the like. Can be mentioned.
The content of the other additives is appropriately set according to the type of the additive and is not particularly limited, but is preferably 10 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin (A), and 0 parts by mass. It may be.

<Method for producing thermoplastic resin composition>
In the thermoplastic resin composition of the present invention, for example, the thermoplastic resin (A), carbon black (B), and other additives as necessary are mixed and dispersed by a V-type blender, a Henschel mixer or the like, The mixture thus obtained is produced by melt-kneading using a melt-kneader such as a screw type extruder, Banbury mixer, pressure kneader, mixing roll or the like. Moreover, you may pelletize a melt-kneaded material using a pelletizer etc. as needed.

<Effect>
The thermoplastic resin composition of the present invention described above contains a thermoplastic resin (A) and carbon black (B), and the thermoplastic resin (A) contains a graft copolymer (C). In addition, the volume average particle diameter of the secondary particles of the carbon black (B) is 200 nm or more, and the ratio of the secondary particles having a particle diameter of 800 nm or more to the whole secondary particles is less than 20% by volume. Since the content is 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the thermoplastic resin (A), it exhibits excellent color tone, molded appearance, weather resistance and impact resistance when formed into a molded product. To do. Further, this molded product can be welded by laser welding, vibration welding or hot plate welding, and the welded portion is excellent in appearance. Moreover, sufficient joining strength can be expressed.

"Molding"
The molded article of the present invention uses 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, vibration welding, hot plate welding or the like. For example, a resin joined body can be obtained by welding the molded products of the present invention or the molded product of the present invention and another resin molded product by laser welding, vibration welding, or hot plate welding. Such a resin bonded body is excellent in the appearance of the welded portion and the bonding strength.

  Examples of the use of the molded article of the present invention and the resin joined body using the same include parts for vehicles such as lamps, interior and exterior, OA equipment, home appliance parts, medical instruments, various industrial materials, and the like. A vehicle lamp is preferred.

Hereinafter, an example is shown concretely. However, the present invention is not limited to the following examples. In the following examples, “%” and “part” are based on mass unless otherwise specified.
Various measurements and evaluation methods in the following examples and comparative examples are as follows.

<Evaluation of impact resistance>
In accordance with ISO 3167, a test piece (molded product (1)) was prepared from a pellet-shaped thermoplastic resin composition by an injection molding machine (“IS55FP-1.5A” manufactured by Toshiba Machine Co., Ltd.). The Charpy impact strength of this test piece was measured in a 23 ° C. atmosphere with a notch according to ISO 179-1: 2000.

<Evaluation of laser welding appearance>
From the pellet-shaped thermoplastic resin composition produced in each 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 these conditions, a plate-like molded product (2) having a length of 100 mm, a width of 100 mm, and a thickness of 2 mm was produced, and this was used as an absorbent material.
A permeable material was prepared in the same procedure as the absorbent material, except that the resin used was changed from the pellet-shaped thermoplastic resin composition produced in each example to a pellet-shaped acrylic resin.
Absorbing material and transmitting material are overlapped, and laser light is used under the conditions of output: 3 W, focal diameter: 2 mm, scanning speed: 20 mm / second, welding length: 30 mm, using “Laser welding machine NOVOLAS-C type” manufactured by Leister. Was irradiated from the transmission material side and welded to the absorbent material to obtain a joined body. Then, the welding appearance of the joint surface of the joined body was visually observed and evaluated according to the following criteria.
○: No foaming.
Δ: Partially foamed.
X: There is foaming or scorching on the whole.

<Evaluation of vibration welding appearance>
From the pellet-shaped thermoplastic resin composition produced in each example, a 2 mm thick flat plate molded product (trapezoid, width 70 mm, short side 110 mm, long side 160 mm) was obtained by injection molding.
The obtained flat plate molded article and the evaluation lens were vibration welded to obtain a joined body. As an evaluation lens, polymethylmethacrylate (PMMA) resin (Acrypet VH4 manufactured by Mitsubishi Rayon Co., Ltd.) is injection-molded with a 3 mm ribbed sheet (trapezoid, width 70 mm, short side 110 mm, long side 160 mm, rib: high 10 mm long, 100 mm short side, 150 mm long side) were used. The vibration welding was performed under the conditions of an amplitude of 1 mm, a pressure of 0.3 MPa, and a sinking amount of 1.5 mm using BRANSON VIBRATION WELDER 2407 manufactured by Nippon Emerson Co., Ltd.
The number of yarn burrs produced by melting and joining during vibration welding was visually observed and evaluated according to the following criteria.
○: 0 or more and less than 15
Δ: 15 or more and less than 20.
X: 20 or more.

<Evaluation of hot plate welding appearance>
A test sheet (25 mm × 100 mm × 3 mm) was obtained from the pellet-shaped thermoplastic resin composition produced in each example by injection molding.
The obtained test sheet was brought into contact with a hot plate heated to 220 ° C. for 12 seconds and then pulled horizontally. The number of stringers of 5 mm or more at that time was visually observed and evaluated according to the following criteria.
○: 0 or more and less than 5.
Δ: 5 or more and less than 15
X: 15 or more.

<Evaluation of color tone>
A molded product (2) was produced in the same manner as described above, and the color tone (L *) was measured with a colorimeter using the molded product (2). It shows that the blackness of a molded product is deep (dark), so that the value of L * is small.

<Evaluation of molding appearance (measurement of diffuse reflectance)>
A molded product (2) was produced in the same manner as described above. An aluminum film having a thickness of 50 nm is formed on the surface of the molded product (2) by a vacuum deposition method (VPC-1100 manufactured by ULVAC) under the conditions of a degree of vacuum of 6.0 × 10 ⁻³ Pa and a film formation rate of 10 Å / second. (Direct evaporation). About the film-forming surface of the obtained molded product (2), diffuse reflectance Rd (%) was measured with a reflectometer (TR-1100AD manufactured by Tokyo Denshoku). It shows that it is excellent in the glossiness of the surface of a molded article, so that the value of diffuse reflectance Rd is low.

<Evaluation of weather resistance>
A molded product (2) was produced in the same manner as described above. Using “Sunshine Super Long Life Weather Meter WEL-SUN-DCH type” manufactured by Suga Test Instruments Co., Ltd., the molded product (2) is 1000 hours in an environment of 63 ° C. and cycle condition: 60 minutes (rainfall: 12 minutes). Exposed. The degree of color change (ΔE) of the molded product before and after exposure for 1000 hours was measured using a color difference meter.

<Measurement of Volume Average Particle Size and Particle Size Distribution of Secondary Particles of Carbon Black (B)>
Carbon black (B) was dispersed in N-methylpyrrolidone, and a 0.04% dispersion was used to measure the volume-based particle size distribution by dynamic light scattering using a Nanotrac UPA-EX150 manufactured by Nikkiso Co., Ltd. The particle size was determined.
In the volume-based particle size distribution, the particle size at which the cumulative value is 10% is 10% cumulative particle size (d10), and the particle size at 50% is 50% cumulative particle size (d50), 90%. The particle diameter was determined as a 90% cumulative particle diameter (d90), and the value of M was calculated from the equation (1).

"Production of acid group-containing copolymer latex"
<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.

"Manufacture of polyorganosiloxane"
<Production Example 2: Production of polyorganosiloxane (E)>
98 parts of octamethylcyclotetrasiloxane and 2 parts of γ-methacryloyloxypropyldimethoxymethylsilane were mixed to obtain 100 parts of a siloxane mixture. To this, an aqueous solution consisting of 0.67 parts of sodium dodecylbenzenesulfonate and 300 parts of ion-exchanged water was added and 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.
While this acid catalyst aqueous solution was 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 (E).
When 2 g of the obtained latex of polyorganosiloxane (E) was dried at 180 ° C. for 30 minutes and the solid content was determined, it was 18.2%. Moreover, the average particle diameter based on mass of the polyorganosiloxane (E) in the latex was 50 nm.

"Production of graft copolymer"
<Production Example 3: Production of Graft Copolymer (C-1)>
In a reactor equipped with a reagent injection container, a condenser, a jacket heater and a stirrer, 2.0 parts of latex of polyorganosiloxane (E) 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. (Radical polymerization step). The obtained composite rubber had a volume average particle diameter of 90 nm.
After the liquid temperature inside the reactor dropped to 70 ° C., 0.60 part of 5% sodium pyrophosphate aqueous solution was added as a solid content. After controlling the internal temperature at 70 ° C., 0.60 part of acid group-containing copolymer latex (K) was added as a solid content, stirred for 30 minutes and enlarged to obtain a composite rubber-like polymer latex ( Enlargement process).
The volume average particle diameter of the composite rubber-like polymer in the obtained latex was 180 nm. The gel content was 88%.

An aqueous solution comprising 0.001 part of ferrous sulfate heptahydrate, 0.003 part of disodium ethylenediaminetetraacetate, 0.3 part of Rongalite and 10 parts of ion-exchanged water was added to the latex of this composite rubber-like polymer. . Next, 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 to polymerize. After completion of dropping, the mixture was 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 the dropwise addition, the state at a temperature of 75 ° C. is maintained for 30 minutes, and then 0.05 part of cumene hydroperoxide is added. A latex of a silicone / acrylic composite rubber-based graft copolymer (C-1) obtained by graft polymerization of acrylonitrile and styrene was obtained.
Subsequently, 150 parts of a 1% calcium acetate aqueous solution was heated to 60 ° C., and 100 parts of the latex of the graft copolymer (C-1) was gradually dropped into the solution to be solidified. Then, the precipitate was separated, dehydrated, washed and dried to obtain a composite rubber-like polymer graft copolymer (C-1).

<Production Example 4: Production of Graft Copolymer (C-2)>
In a reactor equipped with a reagent injection container, a condenser, a jacket heater and a stirrer, 150 parts of ion exchange water, 50 parts of polybutadiene latex (volume average particle diameter 180 nm) in terms of solid content, potassium disproportionated potassium 1 part and 0.03 part of potassium hydroxide were added and heated to 60 ° C., and then 0.007 part of ferrous sulfate heptahydrate, 0.1 part of sodium pyrophosphate and 0.3 part of crystalline glucose were added. Subsequently, a mixed liquid consisting 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 acrylonitrile and styrene were added to polybutadiene. A latex of polybutadiene graft copolymer (C-2) obtained by graft polymerization was obtained.
Next, an antioxidant was added to the latex of the graft copolymer (C-2). 150 parts of a 1% aqueous sulfuric acid solution was heated to 60 ° C., and 100 parts of a latex of a graft copolymer (C-2) to which an antioxidant was added was gradually dropped and solidified. Then, the precipitate was separated, dehydrated, washed, and dried to obtain a graft copolymer (C-2).

"Other thermoplastic resin (D)"
<Production Example 5: Production of other thermoplastic resin (D-1)>
27 parts of acrylonitrile and 73 parts of styrene were polymerized by known suspension polymerization 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 (D-1).

<Production Example 6: Production of other thermoplastic resin (D-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 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 (D-2).

"Carbon black (B)"
(B-1) “RB-92995S” manufactured by Koshigaya Chemical Co., Ltd.
(B-2) “ABF-TT2351-G” manufactured by Resino Color Industry Co., Ltd.
(B-3) “DBSP-3687HC” manufactured by Maeda Kasei Co., Ltd.
(B-4) “FW285” manufactured by Orion Engineered Carbons Co., Ltd.
(B-5) “BP2000” manufactured by Cabot Japan.
(B-6) “# 44” manufactured by Mitsubishi Chemical Corporation.

"Examples 1-6, Comparative Examples 1-6"
The types and amounts (parts) of graft copolymers (C), other thermoplastic resins (D) and carbon black (B) shown in Tables 1 and 2, 1 part of ethylene bisstearylamide, silicone oil SH200 (Toray Industries, Inc.) -0.2 parts of ADK STAB AO-60 (manufactured by ADEKA) and 0.4 part of ADK STAB LA-57 (manufactured by ADEKA) using a Henschel mixer. Mixed. The obtained mixture was melt-kneaded at 250 ° C. using a screw type extruder (manufactured by Nippon Steel Co., Ltd., TEX-30α type twin screw extruder), then pelletized by a pelletizer and pelletized thermoplastic. A resin composition was obtained.
About the obtained thermoplastic resin composition, impact resistance, laser welding appearance, vibration welding appearance, hot plate welding appearance, color tone, weather resistance, and molding appearance were evaluated by the above procedures. These results are shown in Tables 1-2.
In addition, the characteristics of the secondary particles of carbon black (B) used in each example (volume average particle diameter, ratio of secondary particles having a particle diameter of 800 nm or more, M value obtained from particle diameter distribution) are shown in Tables 1-2. It is written together.

As shown in Tables 1-2, from the thermoplastic resin composition obtained in each example, it is excellent in color tone, molding appearance, weather resistance, impact resistance, laser welding appearance, vibration welding appearance and hot plate welding appearance. A molded product was obtained.
On the other hand, in the case of each comparative example, the color tone, molded appearance, weather resistance, impact resistance, laser welding appearance, vibration welding appearance, and hot plate welding appearance of the molded product were inferior.
Specifically, in the case of Comparative Example 1, the ratio of secondary particles having a particle diameter of 800 nm or more to the entire secondary particles of carbon black (B) is 20% or more, so that the laser welding appearance was inferior.
In the case of Comparative Example 2, since the content of carbon black (B) was small, the color tone and laser welding appearance were inferior.
In the case of Comparative Example 3, since the content of carbon black (B) was large, the impact resistance and the appearance of laser welding were inferior.
In Comparative Example 4, since the graft copolymer (C) was not contained, impact resistance, laser welding appearance, vibration welding appearance, and hot plate welding appearance were inferior.
In the case of Comparative Example 5, since the graft copolymer did not contain a composite rubber-like polymer in which a polyorganosiloxane and an alkyl (meth) acrylate polymer were combined, the molding appearance and weather resistance were inferior.
In the case of Comparative Example 6, since the volume average particle diameter of the secondary particles of carbon black (B) is 200 nm or less, the laser welding appearance was inferior.

  According to the present invention, a molded product having excellent color tone, molded appearance, weather resistance, and appearance after welding by laser welding, vibration welding, or hot plate welding and having sufficient impact resistance as a resin member can be obtained. A thermoplastic resin composition can be provided. 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 a conventionally known thermoplastic resin composition, such as parts for vehicles such as lamps, interiors and exteriors, and OA equipment. And its utility value as home appliance parts, medical equipment, and various industrial materials is extremely high.

Claims (3)

Containing a thermoplastic resin (A) and carbon black (B),
The thermoplastic resin (A) contains a graft copolymer (C) obtained by grafting a vinyl polymer to a composite rubber-like polymer in which a polyorganosiloxane and an alkyl (meth) acrylate polymer are combined.
In the carbon black (B), the volume average particle diameter of secondary particles is 200 nm or more, and the ratio of secondary particles having a particle diameter of 800 nm or more to the whole secondary particles is less than 20% by volume,
Content of the said carbon black (B) is 0.1-3.0 mass parts with respect to 100 mass parts of said thermoplastic resins (A), The thermoplastic resin composition characterized by the above-mentioned. In the volume-based particle size distribution of the carbon black (B), the particle size at which the cumulative value is 10% is 10% cumulative particle size (d10), and the particle size at which the cumulative value is 50% is 50% cumulative particle size ( d50), where the particle size at which the cumulative value is 90% is 90% cumulative particle size (d90), M obtained by the following equation (1) satisfies the following equation (2). Thermoplastic resin composition.
M = (d90−d10) / d50 (1)
1.5 ≦ M ≦ 2.5 (2)   A molded article using the thermoplastic resin composition according to claim 1.