Laser-transmitting resin composition, molded article, and composite molded article

Abstract

Provided are: a resin composition which is colored black and has high laser light transmittance; and a molded article and a composite molded article which use the resin composition. A laser-transmitting resin composition containing a polybutylene terephthalate resin, a polycarbonate resin, and a chromium complex azo dye, the polycarbonate resin being contained in an amount of 60-100 parts by mass per 100 parts by mass of the polybutylene terephthalate resin, the content of the chromium complex azo dye is from 0.08 parts by mass to 0.50 parts by mass (inclusive) with respect to 100 parts by mass of the polybutylene terephthalate resin.

Description

Technical Field

[0001] The present invention relates to a laser-transmitting resin composition, a molded product and a composite molded product. Background Art

[0002] Polybutylene terephthalate resin has excellent heat resistance, mechanical strength, dimensional stability, electrical properties and moldability, and is widely used in the electrical / electronic fields, the automotive field, etc. Resin molded products are usually used in combination with other parts, and in recent years, laser welding has been widely used for their joining.

[0003] Laser welding is a joining method in which a resin molded product having laser transmittance and a resin molded product having laser absorbance are overlapped and a laser beam is irradiated from the side of the resin molded product having laser transmittance to perform welding.

[0004] Polybutylene terephthalate resin is not suitable for manufacturing laser-transmitting side molded products because it has low laser transmittance compared to polystyrene resin and polyamide resin. In addition, carbon black, which is commonly used as a colorant for coloring resin in black, absorbs laser light even when mixed in a very small amount, and therefore cannot be used for laser-transmitting side molded products. Therefore, when coloring laser-transmitting side molded products in black, organic dyes and pigments with laser transmittance are used. Patent Document 1 describes a resin composition colored in black containing a plurality of color pigments. Patent Document 2 describes a resin composition colored in a dark color containing a polymer pigment.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-199861

[0006] Patent Document 2: Japanese Patent Application Publication No. 2007-297473 Summary of the invention

[0007] Organic dye or pigment has the heat resistance that can be used in polybutylene terephthalate, laser transmittance is high, and basically does not develop into black. Therefore, when the organic dye or pigment is less in the mixing amount under a single color, it can develop into red, green, etc., and is not easy to develop into black. Although it becomes dark when the mixing amount is many, the light transmittance of the resin combination can be greatly reduced. For such reasons, when using the organic dye or pigment, a plurality of dyes or pigments with different colors are combined and mixed as much as possible in a small amount, so that it must be adjusted to black. However, the covering property of polybutylene terephthalate resin is high, therefore, even when using a variety of dyes, pigments to be colored as black, compared with other resins, it is necessary to increase the mixing amount of dyes, pigments, and as a result, laser transmittance is sometimes further reduced.

[0008] An object of the present invention is to provide a resin composition which is colored black and has high laser transmittance, and a molded article and a composite molded article using the same.

[0009] The present invention has the following aspects.

[0010] [1] A laser-transmitting resin composition comprising a polybutylene terephthalate resin, a polycarbonate resin and a chromium complex azo dye,

[0011] The content of the polycarbonate resin is 60 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of the polybutylene terephthalate resin.

[0012] The content of the chromium complex azo dye is 0.08 parts by mass or more and 0.50 parts by mass or less relative to 100 parts by mass of the polybutylene terephthalate resin.

[0013] [2] The laser-transmitting resin composition according to [1], further comprising a filler, wherein the content of the filler is 10 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the polybutylene terephthalate resin.

[0014] [3] The laser-transmitting resin composition according to [1] or [2], wherein in a molded article having a thickness of 1 mm, the L* value in the CIE colorimetric system is 20 or less, and the light transmittance at a wavelength of 940 nm is 50% or more.

[0015] [4] The laser-transmitting resin composition according to any one of [1] to [3], wherein the chromium complex azo dye includes Color Index (CI) Solvent Black 28.

[0016] [5] The laser-transmitting resin composition according to any one of [1] to [4], wherein the polycarbonate resin has a temperature of 300° C. and a shear rate of 1000 sec. -1 The melt viscosity is 0.20 kPa·s or more.

[0017] [6] A molded article for laser welding, comprising the laser-transmitting resin composition according to any one of [1] to [5].

[0018] [7] The molded article according to [6], which is a laser-transmitting-side molded article.

[0019] [8] A composite molded product comprising the molded product described in [7] and a laser absorbing side molded product.

[0020] According to the present invention, there can be provided a resin composition which is colored black and has high laser transmittance, and a molded article and a composite molded article using the same. DETAILED DESCRIPTION

[0021] Hereinafter, an embodiment of the present invention is described in detail, but the scope of the present invention is not limited to the embodiment described herein, and various changes can be made within the scope of the gist of the present invention. In addition, for a specific parameter, when a plurality of upper and lower limits are recorded, any upper and lower limits in these upper and lower limits can be combined to form a suitable numerical range. The specific description recorded in an embodiment is also applicable to other embodiments, and the description is sometimes omitted in other embodiments.

[0022] [Laser-transmitting resin composition]

[0023] The laser-transmissive resin composition of the present embodiment (hereinafter also referred to as "resin composition") comprises: polybutylene terephthalate resin, polycarbonate resin and chromium complex azo dye, wherein the content of polycarbonate resin is greater than 60 parts by mass and less than 100 parts by mass relative to 100 parts by mass of polybutylene terephthalate resin, and the content of chromium complex azo dye is greater than 0.08 parts by mass and less than 0.50 parts by mass relative to 100 parts by mass of polybutylene terephthalate resin.

[0024] By containing the polybutylene terephthalate resin, the polycarbonate resin, and the chromium complex azo dye in predetermined amounts, a resin composition that is colored black and has high laser transmittance can be formed.

[0025] (Polybutylene terephthalate resin)

[0026] Polybutylene terephthalate resin (PBT resin) is a resin containing at least terephthalic acid or its ester-forming derivative (C 1-6 A polybutylene terephthalate resin obtained by polycondensing a dicarboxylic acid component (e.g., an alkyl ester, an acyl halide, etc.) with a diol component containing at least an alkylene glycol having 4 carbon atoms (1,4-butanediol) or an ester-forming derivative thereof (acetylated product, etc.). In the present embodiment, the polybutylene terephthalate resin is not limited to a homopolybutylene terephthalate resin, and may be a copolymer containing 60 mol % or more of a butylene terephthalate unit.

[0027] The amount of terminal carboxyl groups in the polybutylene terephthalate resin is preferably 50 meq / kg or less, more preferably 30 meq / kg or less, and further preferably 25 meq / kg or less.

[0028] The intrinsic viscosity of the polybutylene terephthalate resin is not particularly limited within the range that does not hinder the effect of the present invention, and is preferably 0.60 dL / g or more and 1.2 dL / g or less, and more preferably 0.65 dL / g or more and 0.9 dL / g or less. When a polybutylene terephthalate resin with an intrinsic viscosity in such a range is used, the obtained polybutylene terephthalate resin composition has excellent moldability, in particular. In addition, polybutylene terephthalate resins with different intrinsic viscosities can also be blended to adjust the intrinsic viscosity. For example, a polybutylene terephthalate resin with an intrinsic viscosity of 1.0 dL / g is blended with a polybutylene terephthalate resin with an intrinsic viscosity of 0.7 dL / g, so that a polybutylene terephthalate resin with an intrinsic viscosity of 0.9 dL / g can be prepared. The intrinsic viscosity of the polybutylene terephthalate resin can be measured, for example, in o-chlorophenol at a temperature of 35°C.

[0029] In the preparation of the polybutylene terephthalate resin, when an aromatic dicarboxylic acid other than terephthalic acid or an ester-forming derivative thereof is used as a comonomer component, for example, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-dicarboxy diphenyl ether, etc. can be used. 8-14 Aromatic dicarboxylic acids; succinic acid, adipic acid, azelaic acid, sebacic acid, etc. 4-16 Alkanedicarboxylic acids; cyclohexanedicarboxylic acid, etc. 5-10 Cycloalkane dicarboxylic acids; ester-forming derivatives of these dicarboxylic acid components (C 1-6 These dicarboxylic acid components may be used alone or in combination of two or more.

[0030] Among these dicarboxylic acid components, C 8-12 Aromatic dicarboxylic acids, adipic acid, azelaic acid, sebacic acid, etc. 6-12 of alkane dicarboxylic acids.

[0031] In the preparation of the polybutylene terephthalate resin, when a diol component other than 1,4-butanediol is used as a comonomer component, for example, ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, hexamethylene glycol, neopentyl glycol, 1,3-octanediol, etc. can be used. 2-10 alkylene glycols; polyoxyalkylene glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol; alicyclic diols such as cyclohexanedimethanol and hydrogenated bisphenol A; aromatic diols such as bisphenol A and 4,4'-dihydroxybiphenyl; C-type adducts of bisphenol A such as 2-mole adducts of ethylene oxide and 3-mole adducts of bisphenol A 2-4 or ester-forming derivatives (acetylated products, etc.) of these diols. These diol components can be used alone or in combination of two or more.

[0032] Among these diol components, ethylene glycol, trimethylene glycol and the like are more preferred. 2-6 alkylene glycol, polyoxyalkylene glycol such as diethylene glycol, or alicyclic glycol such as cyclohexanedimethanol.

[0033] Examples of the comonomer component that can be used in addition to the dicarboxylic acid component and the diol component include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 4-carboxy-4'-hydroxybiphenyl; aliphatic hydroxycarboxylic acids such as glycolic acid and hydroxycaproic acid; C-1-6-hydroxy-1 ... 3-12 Lactones; ester-forming derivatives of these comonomer components (C 1-6 alkyl ester derivatives, acyl halides, acetylates, etc.).

[0034] The content of polybutylene terephthalate resin is preferably 30% by mass or more and 65% by mass or less of the total mass of the resin composition, more preferably 35% by mass or more and 60% by mass or less, further preferably 38% by mass or more and 50% by mass or less, and may be set to 40% by mass or more and 50% by mass or less. When the content of polybutylene terephthalate resin is 30% by mass or more and 65% by mass or less of the total mass of the resin composition, it may be 38% by mass, 39% by mass, or a range using them as lower limits or upper limits.

[0035] (Polycarbonate resin)

[0036] As polycarbonate resin (PC resin), a polymer obtained by the reaction of a dihydroxy compound with a carbonate such as phosgene or diphenyl carbonate can be cited. The dihydroxy compound can be an alicyclic compound such as an alicyclic diol, but is preferably an aromatic compound, more preferably a bisphenol compound. The dihydroxy compound can be used alone or in combination of two or more.

[0037] Examples of the bisphenol compound include bis(4-hydroxyphenyl)methane, bis(4-hydroxy-3-methylphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxy-3-methylphenyl)ethane, 1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-ethylphenyl)propane, 2,2-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromo ... 2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxyphenyl)hexane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)dibenzylmethane, 1,1-bis(4-hydroxyphenyl)-1-phenylpropane, 2,2,2',2'-tetrahydro-3,3,3',3'-tetramethyl-1,1'-spirobis-[1H-indene]-6,6'-diol and other bis(hydroxyaryl)C 1-10 Alkanes, preferably bis(hydroxyaryl)C 1-6 Alkanes; 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane and other bis(hydroxyaryl)C 4-10 Cycloalkanes; dihydroxyaryl ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether; dihydroxyaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone; dihydroxyaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide; dihydroxyaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; dihydroxyaryl ketones such as 4,4'-dihydroxydiphenyl ketone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ketone, etc.

[0038] As a preferable polycarbonate resin, bisphenol A type polycarbonate is mentioned.

[0039] The polycarbonate resin may be a homopolycarbonate or a copolycarbonate. The polycarbonate resin may be used alone or in combination of two or more.

[0040] Polycarbonate resin at 300°C, shear rate 1000 sec -1The melt viscosity at 0.20 kPa·s or more is preferably 0.21 kPa·s or more, further preferably 0.22 kPa·s or more, further preferably 0.24 kPa·s or more, and particularly preferably 0.25 kPa·s or more. The melt viscosity is measured in accordance with ISO11443.

[0041] The content of the polycarbonate resin is 60 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the polybutylene terephthalate resin, preferably 65 parts by mass or more and 90 parts by mass or less, more preferably 70 parts by mass or more and 85 parts by mass or less, further preferably 72 parts by mass or more and 82 parts by mass or less, and particularly preferably 75 parts by mass or more and 80 parts by mass or less. If the content of the polycarbonate resin is less than 60 parts by mass, the laser transmittance is insufficient, and it is impossible to balance the coloring of the resin composition into black and the improvement of the laser transmittance. If the content of the polycarbonate resin exceeds 100 parts by mass, the crystallization of the polybutylene terephthalate resin is reduced, and sometimes the heat resistance and chemical resistance are reduced, and poor demolding occurs during molding, which is not preferred.

[0042] The content of the polycarbonate resin is within the range of 60 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the polybutylene terephthalate resin, and can be 76.1 parts by mass, 78.1 parts by mass, or 78.3 parts by mass, or a range with these as the lower limit or upper limit, or a range combining these.

[0043] In one embodiment, the total content of the polybutylene terephthalate resin and the polycarbonate resin in the thermoplastic resin contained in the resin composition is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 100% by mass, relative to the total mass of the thermoplastic resin. In one embodiment, the thermoplastic resin in the resin composition may consist only of the polybutylene terephthalate resin and the polycarbonate resin (B).

[0044] (Chromium complex azo dyes)

[0045] The chromium complex azo dye is preferably a 1:2 type chromium complex azo dye, and examples thereof include Color Index (CI) Solvent Black 28 (CAS No. 12237-23-9) and Color Index (CI) Solvent Black 35 (CAS No. 61631-53-1), and more preferably includes one or more selected from these. In one embodiment, the chromium complex azo dye is preferably Color Index (CI) Solvent Black 28.

[0046] When the chromium complex azo dye is mixed with polybutylene terephthalate resin in the same manner as carbon black, the transmittance is reduced even in a small amount. However, surprisingly, if polybutylene terephthalate resin, polycarbonate and chromium complex azo dye are mixed in a specified amount, a resin composition colored black and having high laser transmittance can be formed.

[0047] Chromium complex azo dyes rarely sublimate in an environment using polybutylene terephthalate resins, and are less likely to cause malfunctions due to contamination, for example, even when used in housings of electronic products. In addition, color transfer is rare, so when a molded product of the resin composition is placed in contact with other resin components and stored, contamination of other resin components is rare, and reduction in design properties and adhesion of dyes are also rare.

[0048] Chromium complex azo dyes have low transmittance like polybutylene terephthalate resins, and when mixed with resins with high hiding power, transmittance is reduced, so they are not suitable for transmissive materials for laser welding. However, the resin composition of this embodiment is monochromatic and can be colored black with a small amount, so it can be used as a colorant added to transmissive materials for laser welding. Therefore, it is not necessary to use a combination of multiple types like existing organic dyes and pigments, and it is not necessary to study the type, mixing amount, mixing ratio, etc., so productivity is improved.

[0049] The content of chromium complex azo dye is 0.08 mass parts or more and 0.50 mass parts or less relative to 100 mass parts of polybutylene terephthalate resin, preferably 0.09 mass parts or more and 0.45 mass parts or less, more preferably 0.10 mass parts or more and 0.40 mass parts or less, further preferably 0.13 mass parts or more and 0.40 mass parts or less. If the content of chromium complex azo dye is less than 0.08 mass parts, brightness (L* value) becomes high, and it is not easy to be colored as black. If the content of chromium complex azo dye exceeds 0.50 mass parts, laser transmittance is sometimes reduced. The content of chromium complex azo dye is 0.08 mass parts or more and 0.50 mass parts or less relative to 100 mass parts of polybutylene terephthalate resin, it can be 0.13 mass parts, it can be 0.39 mass parts, it can be the scope of using them as the lower limit or upper limit, it can be the scope of combining them.

[0050] Even if the chromium complex azo dye does not use other dyes and pigments, the resin combination can be colored black alone, but the resin combination can also include other colorants beyond the chromium complex azo dyes within the scope of the effect of the present invention. As other colorants, organic dyes and pigments can be enumerated. As organic dyes and pigments, for example, yellow pigments (for example anthraquinone yellow pigments), green pigments (for example phthalocyanine green pigments), violet pigments (for example pyrene violet pigments) etc. can be enumerated. Organic dyes and pigments can be used alone or in combination of more than 2 kinds and used.

[0051] From the viewpoint of further improving laser transmittance and preventing color transfer of molded products, the content of organic dyes and pigments is preferably small, for example, preferably less than 0.40 parts by mass, more preferably less than 0.10 parts by mass, relative to 100 parts by mass of polybutylene terephthalate resin.

[0052] In one embodiment, the resin composition may contain a colorant containing a chromium complex azo dye. In one embodiment, the content of the chromium complex azo dye in the colorant is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 98% by mass, and may be 100% by mass. In one embodiment, the colorant may consist only of a chromium complex azo dye.

[0053] (Bulking Agent)

[0054] From the viewpoint of improving mechanical strength, the resin composition can contain fillers as needed. As fillers, organic or inorganic fillers can be cited, for example, fibrous fillers, plate-like fillers, or granular fillers can be cited. As fibrous fillers, for example, inorganic fibers such as glass fibers, asbestos fibers, silica fibers, alumina fibers, silica-alumina fibers, aluminosilicate fibers, zirconium oxide fibers, potassium titanate fibers, whiskers (alumina, silicon nitride whiskers) can be cited; organic fibers such as acrylic resins such as aliphatic or aromatic polyamides, aromatic polyesters, fluororesins, polyacrylonitrile, and fibers formed by rayon, etc. can be cited. As plate-like fillers, for example, talc, mica, glass flakes, etc. can be cited. As granular fillers, for example, glass beads, glass powder, ground fibers (such as ground glass fibers, etc.), wollastonite (wollastonite), etc. can be cited. It should be noted that wollastonite can be in the form of plates, columns, fibers, etc. The filler can be used alone or in combination of two or more. Among these inorganic fillers, glass fiber is preferred from the viewpoints of improving heat resistance and mechanical strength without impairing laser transmittance and being inexpensive and easily available.

[0055] The average fiber diameter of the fibrous filler can be, for example, about 1 μm to 30 μm (preferably 3 μm to 20 μm), and the average fiber length can be, for example, about 100 μm to 5 mm (preferably 300 μm to 4 mm, more preferably 500 μm to 3.5 mm). In addition, the average primary particle size of the plate-like or powdery filler can be, for example, about 10 μm to 500 μm, preferably about 15 μm to 100 μm.

[0056] It should be noted that the average fiber diameter and average fiber length of the fibrous filler and the average primary particle size of the plate-like or granular filler are values ​​calculated as follows: for the fibrous filler and the plate-like or granular filler before being mixed in the resin composition, an image captured by analyzing a CCD camera is analyzed and the values ​​are calculated by weighted averaging. For example, they can be calculated using a dynamic image analysis method / particle (state) analyzer PITA-3 manufactured by SEISHIN ENTERPRISE Co., Ltd.

[0057] The content of the inorganic filler is preferably 10 parts by mass or more and 140 parts by mass or less, more preferably 10 parts by mass or more and 100 parts by mass or less, further preferably 30 parts by mass or more and 100 parts by mass or less, and particularly preferably 50 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the polybutylene terephthalate resin. When the content of the inorganic filler is 10 parts by mass or more and 140 parts by mass or less, relative to 100 parts by mass of the polybutylene terephthalate resin, it may be 76.1 parts by mass, 78.1 parts by mass, 78.3 parts by mass, or a range in which these are used as lower limits or upper limits, or a range combining these.

[0058] (Other additives)

[0059] The resin composition can be compounded with known substances usually added to thermoplastic resins and thermosetting resins, such as antioxidants, stabilizers such as ultraviolet absorbers, ester exchange inhibitors (such as calcium dihydrogen phosphate), hydrolysis resistance improvers, plasticizers, antistatic agents, flame retardants, flame retardant aids, anti-drip agents, mold release agents, lubricants, crystallization accelerators, crystallization nucleating agents (such as boron nitride, etc.), etc., within the range that does not hinder the effects of the present invention, so as to impart the desired properties that meet its purpose.

[0060] For example, for the purpose of improving hydrolysis resistance, the resin composition may contain an epoxy resin. As the epoxy resin, for example, biphenyl epoxy resin, bisphenol A epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, etc. can be cited. One epoxy resin can be used alone, or two or more epoxy resins can be used in combination. The content of the epoxy resin is preferably 1 to 10 parts by mass, more preferably 1.5 to 5 parts by mass, and further preferably 2 to 4 parts by mass relative to 100 parts by mass of the polybutylene terephthalate resin. When the content of the epoxy resin is 1 to 10 parts by mass relative to 100 parts by mass of the polybutylene terephthalate resin, it can be 2.6 parts by mass, which can be a range with it as the lower limit or upper limit.

[0061] The resin composition may contain other thermoplastic resins other than the polybutylene terephthalate resin and the polycarbonate resin as necessary.

[0062] For example, the resin composition may contain elastomers such as olefin elastomers, styrene elastomers, polyester elastomers, core-shell polymers, etc. The elastomer can improve the impact resistance and reduce the elastic modulus, thereby increasing the adhesion between the laser transmission side molded product and the laser absorption side molded product during laser welding, and improving the weldability.

[0063] The resin composition of this embodiment has high laser transmittance and excellent warpage deformation, so even without adding an elastomer, a resin composition with excellent laser weldability can be formed. In one embodiment, the content of the elastomer in the resin composition can be set to less than 10 parts by mass, less than 5 parts by mass, or less than 1 part by mass relative to 100 parts by mass of the polybutylene terephthalate resin. In one embodiment, the resin composition can be configured in a manner that does not contain an elastomer.

[0064] When polybutylene terephthalate resin and polyamide resin are used together, there is a tendency that brightness (L* value) becomes high, it is difficult to be colored black, and laser transmittance decreases. Thus, it is preferred that the content of polyamide in the resin composition is small. In one embodiment, in the resin composition, the content of polyamide is preferably less than 10 mass parts, more preferably less than 5 mass parts, and further preferably less than 1 mass part relative to 100 mass parts of polybutylene terephthalate resin. In one embodiment, the resin composition preferably does not contain polyamide resin.

[0065] The resin composition preferably does not contain a laser absorbing compound, or contains less than 0.01 mass % of the laser absorbing compound in the resin composition in order to further improve laser transmittance. Examples of the laser absorbing compound include carbon black, aniline black, and nigrosine.

[0066] (Resin composition)

[0067] The method for producing the resin composition is not limited, and examples thereof include the following methods: a method of forming pellets by melt-kneading and extruding the components using a melt-kneading device such as a single-screw extruder or a twin-screw extruder; a method of preparing pellets (master batches) of different compositions and mixing a predetermined amount of the pellets; etc. It should be noted that the pellets can be prepared, for example, by melt-mixing the components other than the brittle component (glass-based reinforcement material, etc.), and then mixing the brittle component.

[0068] In one embodiment, the resin composition is colored black and has a property of transmitting the laser beam when a molded article having a thickness of 1 to 2 mm is irradiated with the laser beam.

[0069] In one embodiment, the resin composition is as follows: in a molded article having a thickness of 1 mm, the L* value in the CIE colorimetric system is preferably 20 or less, and the light transmittance at a wavelength of 940 nm is preferably 50% or more, more preferably 55% or more, and further preferably 60% or more. In a molded article having a thickness of 1 mm, when the L* value in the CIE colorimetric system is 20 or less and the light transmittance at a wavelength of 940 nm is 50% or more, a resin composition colored black and having very high laser transmittance can be formed. As a result, the laser welding can be well joined to the welded body, and an appearance having a sense of unity with the welded body colored black can be formed.

[0070] In one embodiment, the resin composition is such that the L* value in the CIE colorimetric system of a molded article having a thickness of 1 mm may be 15 or less. In this embodiment, the resin composition is such that the light transmittance at a wavelength of 940 nm of a molded article having a thickness of 1 mm may be 60% or more.

[0071] In another embodiment, the resin composition is such that the light transmittance at a wavelength of 940 nm in a molded article having a thickness of 1 mm can be 70% or more. In this embodiment, the resin composition is such that the L* value in the CIE colorimetric system in a molded article having a thickness of 1 mm can be 20 or less.

[0072] The "CIE colorimetric system" (1976) is a quantitative representation of color established by the International Commission on Illumination (Commission Internationale del'Eclairage). The "L* value" is an index that indicates brightness. The L* value in the CIE colorimetric system can be measured using a spectrophotometer.

[0073] In one embodiment, the resin composition is as follows: in a molded article with a thickness of 2 mm, the transmittance at a wavelength of 940 nm is preferably 20% or more, more preferably 25% or more. In a molded article with a thickness of 2 mm, if the transmittance at a wavelength of 940 nm is 20% or more, it can be joined to a welded body by laser welding. In one embodiment, the resin composition is as follows: in a molded article with a thickness of 2 mm, the transmittance at a wavelength of 940 nm can be 40% or more.

[0074] The resin composition of this embodiment can be used for various applications using polybutylene terephthalate resin. In particular, since the resin composition of this embodiment is colored black and has high laser transmittance, it can be preferably used for the manufacture of a laser-transmitting side molded product in a molded product for laser welding.

[0075] [Molding products for laser welding]

[0076] The laser welding molded product of this embodiment is molded using the above-mentioned laser transmissive resin composition, and contains the above-mentioned laser transmissive resin composition. Since it contains the above-mentioned laser transmissive resin composition, it is colored black and has high laser transmissivity. As a result, it can be preferably used as a laser transmissive side molded product. Regarding the laser transmissive resin composition, it is as described above.

[0077] The molding method of the molded article for laser welding is not particularly limited, and a known molding method can be used. For example, the article can be manufactured by a method of molding after adjusting the pellets of the resin composition or by directly adding one or more of the components of the resin composition into a molding machine.

[0078] The molding method may be a common method such as extrusion molding, injection molding, compression molding, blow molding, vacuum molding, rotational molding, gas injection molding, etc., but is usually molded by injection molding. The mold temperature during injection molding is usually 40 to 90°C, preferably 50 to 80°C, and more preferably about 60 to 80°C.

[0079] The shape of the molded product for laser welding is not particularly limited. It is joined and used with a corresponding material (other molded products formed of thermoplastic resin) by laser welding, so it is preferably in a shape having a contact surface such as a plane (e.g., a plate shape). The molded product for laser welding of this embodiment has high transmittance to laser light, so the thickness of the welded portion, that is, the thickness of the molded product at the portion where the laser light is transmitted (the thickness in the direction of laser transmission), can be selected from a wide range, for example, it can be about 0.1 to 3.0 mm, preferably 0.5 to 2.5 mm, and more preferably about 1.0 to 2.0 mm.

[0080] [Composite molded products]

[0081] The composite molded product of the present embodiment includes a laser transmission side molded product (hereinafter also referred to as a "first molded product") and a laser absorption side molded product (hereinafter also referred to as a "second molded product"). The laser transmission side molded product uses the above-mentioned molded product for laser welding of the present embodiment. By using the above-mentioned molded product for laser welding as the laser transmission side molded product, a high bonding strength can be obtained when laser welding is performed, and a composite molded product with a uniform color tone with the laser absorption side molded product usually colored black with carbon black or the like can be formed. The molded product for laser welding as the first molded product is as described above.

[0082] As the main component of the resin constituting the second molded article, it is desirable to use a polyalkylene terephthalate resin. As the polyalkylene terephthalate resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polytrimethylene terephthalate resin, etc. can be cited. "Main component" here means 50% by mass or more relative to the total mass of the resin constituting the second molded article. In one embodiment, the content of the polyalkylene terephthalate resin is preferably more than 50% by mass, more preferably more than 60% by mass relative to the total mass of the resin constituting the second molded article.

[0083] The resin constituting the second molded article may include various thermoplastic resins, such as olefin resins, vinyl resins, styrene resins, acrylic resins, polyester resins, polyamide resins, and polycarbonate resins.

[0084] In one embodiment, the second molded article may be formed of a resin of the same type or system as the resin forming the first molded article (aromatic polyester resins such as PBT resins and PET resins, and / or polycarbonate resins) or a combination thereof.

[0085] The second molded article may contain an absorbent or colorant for laser light. As an absorbent, black pigments or dyes, in particular carbon black (e.g., acetylene black, lamp black, thermal black, furnace black, channel black, Ketjen black, etc.) can usually be used. The average particle size of carbon black is usually 10 to 1000 nm, preferably about 10 to 100 nm. The absorbent can be used alone or in combination of two or more. As a colorant, it can be appropriately selected according to the purpose, for example, inorganic pigments [black pigments such as carbon black (e.g., acetylene black, lamp black, thermal black, furnace black, channel black, Ketjen black, etc.), red pigments such as iron oxide red, orange pigments such as molybdenum orange, white pigments such as titanium oxide, etc.], organic pigments (yellow pigments, orange pigments, red pigments, blue pigments, green pigments, etc.), etc. The colorant can be used alone or in combination of two or more.

[0086] The ratio of the absorbent and the colorant is preferably 0.1 to 10% by mass, more preferably 0.3 to 5% by mass, and even more preferably 0.3 to 3% by mass, based on the entire second molded article.

[0087] The composite molded product preferably joins and integrates the laser transmission side molded product and the laser absorption side molded product by laser welding. For example, the first molded product is brought into contact with the second molded product (especially at least the joining portion is brought into contact with the surface), and a laser beam is irradiated from the first molded product side to melt the interface between the first molded product and the second molded product, and the joining surface is made close and cooled, thereby joining and integrating the two molded products to form a composite molded product. If necessary, a lens system can be used to focus the laser beam on the interface between the first molded product and the second molded product to weld the contact interface.

[0088] The laser source is not particularly limited, and examples thereof include dye lasers, gas lasers (excimer lasers, argon lasers, krypton lasers, helium-neon lasers, etc.), solid lasers (YAG lasers, etc.), semiconductor lasers, etc. As the laser beam, pulse lasers are generally used.

[0089] The irradiation speed of the laser beam is not particularly limited, and can be set to, for example, 10 to 5000 mm / sec.

[0090] Example

[0091] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not to be construed as being limited to these Examples.

[0092] The materials used in Examples and Comparative Examples are as follows.

[0093] [Material]

[0094] (A) Polybutylene terephthalate

[0095] A-1: Polybutylene terephthalate manufactured by Polyplastics Co., Ltd., intrinsic viscosity 0.69 dL / g

[0096] A-2: Polybutylene terephthalate modified with 12.5 mol of isophthalic acid manufactured by Polyplastics Co., Ltd.

[0097] (B) Polycarbonate: Polycarbonate manufactured by Teijin Limited (300°C, shear rate 1000 sec -1 Melt viscosity: 0.27 kPa·s)

[0098] (C) Filler: Glass fiber, manufactured by Nippon Electric Glass Co., Ltd., product name: ECS03 T-127, average fiber diameter 13 μm, average fiber length 3 mm

[0099] (D) Colorant

[0100] D-1: Made by BASF Co., Ltd., Orasol Black X45 (CISolvent Black 28)

[0101] D-2: Phthalocyanine green pigment (CI Pigment Green 7)

[0102] D-3: Anthraquinone yellow pigment (CI Pigment Yellow 147)

[0103] D-4: Pyrene-based purple pigment (CI Pigment Violet 29)

[0104] (E) Polyamide: 1015B manufactured by UBE Corporation

[0105] (F) Polyester elastomer: Pelprene P-90BD manufactured by Toyobo Co., Ltd.

[0106] (G) Calcium dihydrogen phosphate: manufactured by Taihei Chemical Industrial Co., Ltd.

[0107] (H) Antioxidant: Chang Chun Petrochemical, AO-60RG

[0108] (I) Epoxy resin: Epikote 1004K manufactured by Mitsubishi Chemical Corporation

[0109] (J) Lubricant: Riken Vitamin Co., Ltd., L-7640

[0110] (K) Boron nitride: manufactured by JFE Mineral Co., Ltd.

[0111] (L) Plasticizer: Adeka Cizer UL-100 manufactured by Adeka Corporation

[0112] [Examples 1 to 3, Comparative Examples 1 to 8]

[0113] Relative to 100 parts by mass of polybutylene terephthalate resin, the components were mixed in the proportions shown in Tables 1 and 2, and then melt-kneaded and extruded using TEX30 manufactured by Nippon Steel Works, Ltd. at a barrel temperature of 260°C, a discharge rate of 15 kg / h, and a screw speed of 130 rpm to obtain resin composition pellets.

[0114] (Molding conditions)

[0115] The obtained pellets were injection molded using an injection molding machine S-2000i100B manufactured by Fanuc Corporation at a barrel temperature of 260°C and a mold temperature of 80°C to produce test pieces (1) of 80 mm×80 mm×1 mm thickness and test pieces (2) of 80 mm×80 mm×2 mm thickness.

[0116] [evaluate]

[0117] (Laser transmittance)

[0118] The test pieces (1) and (2) 16 were divided into 20 mm × 20 mm squares. The transmittance (%) at a wavelength of 940 nm was measured at the center of each divided piece using a spectrophotometer (V770 manufactured by JASCO Corporation). The lowest transmittance value was taken as a representative value. The results are shown in Tables 1 and 2.

[0119] (CIE L* value)

[0120] For the test pieces (1) and (2), a color computer (manufactured by Nippon Denshoku Co., Ltd., product name: Spectrocolorimeter SE6000) was used to measure the aperture of the test pieces. The L* value in the CIE colorimetric system was measured under the conditions of C light 2 degrees of vision and reflection. When the L* value is 20 or less, it can be judged as black. The results are shown in Tables 1 and 2.

[0121] (Color Shift(Color Shift))

[0122] A test piece for the color transfer test was prepared as follows.

[0123] (1) A cutting piece having a size of 20 mm x 20 mm x 1 mm in thickness was cut out from the above-mentioned test piece (1) to obtain a colored test piece (3).

[0124] (2) 70% by mass of polybutylene terephthalate (manufactured by Polyplastics Co., Ltd., intrinsic viscosity 0.69 dL / g) and 30% by mass of glass fiber (manufactured by Nippon Electric Glass Co., Ltd., product name: ECS03 T-127, average fiber diameter 13 μm, average fiber length 3 mm) were mixed and melt-kneaded and extruded using a TEX30 manufactured by Nippon Steel Works, Ltd. at a barrel temperature of 260°C, a discharge rate of 15 kg / h, and a screw speed of 130 rpm to obtain resin composition pellets. The obtained pellets were injection molded using an injection molding machine S-2000i100B manufactured by Fanuc Corporation at a barrel temperature of 260°C and a mold temperature of 80°C to obtain a molded product of 80 mm×80 mm×1 mm in thickness. A cutting piece of 20 mm×20 mm×1 mm in thickness was cut from the molded product to obtain a non-coloring test piece (4).

[0125] One main surface of the colored test piece (3) was overlapped with one main surface of the non-colored test piece (4), and heated at 130°C for 30 hours in a thermostatic bath manufactured by Espec Corp. After naturally cooling to room temperature (26°C), the overlapped surfaces were opened to visually confirm whether color transfer to the non-colored test piece (4) was observed. The results are shown in Tables 1 and 2.

[0126] [Table 1]

[0127]

[0128] Unit of content: mass parts

[0129] [Table 2]

[0130]

[0131] Unit of content: mass parts

[0132] As shown in Table 1, the resin compositions of Examples 1 to 3 containing a polybutylene terephthalate resin, a polycarbonate resin and a chromium complex azo dye in a predetermined amount are as follows: in a molded article having a thickness of 1 mm, the L* value in the CIE colorimetric system is 20 or less and the light transmittance at a wavelength of 940 nm is 50% or more, and thus, the resin compositions are colored black and have high laser transmittance. In addition, no color transfer can be confirmed even when in contact with an uncolored article at a high temperature.

[0133] As shown in Table 2, the resin composition of Comparative Example 1 in which the content of the chromium complex azo dye was less than the prescribed amount had an L* value in the CIE colorimetric system exceeding 30, had high lightness, and could not be colored black.

[0134] The resin composition of Comparative Example 2 containing a chromium complex azo dye in excess of the prescribed amount has a sufficiently low L* value in the CIE colorimetric system and is colored black, but the light transmittance of a molded article having a thickness of 1 mm at a wavelength of 940 nm is less than 50%, resulting in low laser transmittance.

[0135] The resin compositions of Comparative Examples 3 and 5, in which the content of polycarbonate resin is less than the prescribed amount, are as follows: in Comparative Example 3, the L* value in the CIE colorimetric system is less than 20, but in Comparative Example 5, the L* value exceeds 20, and the light transmittance of the molded products with a thickness of 1 mm of Comparative Examples 3 and 5 at a wavelength of 940 nm is less than 50%, and it is impossible to achieve both coloring to black and improving laser transmittance.

[0136] The resin composition of Comparative Example 4, in which the content of the chromium complex azo dye and the content of the polycarbonate resin were both less than the prescribed amount, had an L* value in the CIE colorimetric system exceeding 50, and could not be colored black. Generally, polybutylene terephthalate modified with 12.5 mol of isophthalic acid has excellent transmittance compared with polybutylene terephthalate, but in Comparative Example 4, in which the content of the polycarbonate resin was less than the prescribed amount, the light transmittance of the molded article with a thickness of 1 mm at a wavelength of 940 nm was less than 50%, resulting in low laser transmittance.

[0137] Although the resin composition of Comparative Example 6, which contains a polybutylene terephthalate resin and a polyamide resin instead of a polycarbonate resin, contains a chromium complex azo dye within a prescribed amount, the L* value in the CIE colorimetric system exceeds 20, the brightness becomes high, and it cannot be colored in black. In addition, the light transmittance of a molded product with a thickness of 1 mm at a wavelength of 940 nm becomes less than 10%, resulting in excessively low laser transmittance.

[0138] Although the resin composition of Comparative Example 7 containing only polybutylene terephthalate resin as the thermoplastic resin contains a chromium complex azo dye within the prescribed amount, the L* value in the CIE colorimetric system exceeds 20, the brightness becomes high, and it cannot be colored in black. In addition, the light transmittance of the molded product with a thickness of 1 mm at a wavelength of 940 nm becomes less than 10%, resulting in excessively low laser transmittance.

[0139] The resin composition of Comparative Example 8, in which the content of the polycarbonate resin is less than the prescribed amount and a pigment other than the three-color chromium complex azo dye is used, has an L* value of 20 or less in the CIE colorimetric system, and can be colored black, but the light transmittance of the molded article with a thickness of 1 mm at a wavelength of 940 nm is 40% or less, resulting in low laser transmittance. In addition, color transfer to other resin molded articles was confirmed.

[0140] Industrial Applicability

[0141] The resin composition of this embodiment is colored black and has high laser transmittance, and therefore can be suitably used in the manufacture of a molded article for laser welding. Specifically, it can be suitably used as a resin component used in the electrical / electronic field, the automotive field, and the like, and has industrial applicability.

Claims

1. A laser-transmitting resin composition comprising a polybutylene terephthalate resin, a polycarbonate resin and a chromium complex azo dye, The content of the polycarbonate resin is 60 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of the polybutylene terephthalate resin. The content of the chromium complex azo dye is 0.08 parts by mass or more and 0.50 parts by mass or less relative to 100 parts by mass of the polybutylene terephthalate resin. 2 . The laser transmissive resin composition according to claim 1 , further comprising a filler, wherein a content of the filler is 10 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of the polybutylene terephthalate resin.

3. The laser-transmitting resin composition according to claim 1 or 2, wherein In a molded article having a thickness of 1 mm, the L* value in the CIE colorimetric system is 20 or less, and the light transmittance at a wavelength of 940 nm is 50% or more.

4. The laser-transmitting resin composition according to claim 1 or 2, wherein The chromium complex azo dyes include the color index (CI) Solvent Black 28.

5. The laser-transmitting resin composition according to claim 1 or 2, wherein Polycarbonate resin at 300°C, shear rate 1000 sec -1 The melt viscosity is 0.20 kPa·s or more. 6 . A molded article for laser welding, comprising the laser-transmitting resin composition according to claim 1 . 7 . The molded article according to claim 6 , which is a laser-transmitting-side molded article.

8. A composite molded product comprising the molded product according to claim 7 and a laser absorbing side molded product.

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