JP2019081363A - Laser welded body - Google Patents

Abstract

To provide a laser welded body integrating two members each including a polybutylene terephthalate material with a high bond strength by laser welding.SOLUTION: A laser welded body has a configuration with a member I and a member II laminated and integrated. The member I includes a laser beam transmission absorption dye material of 0.0005-5.0 pts.mass capable of transmitting and absorbing laser beams, with regard to a polyester resin A 100 pts.mass. The polyester resin A includes homogeneous PBT. The member II includes a laser beam absorption dye material of 0.15-10.00 pts.mass capable of absorbing, without transmitting, laser beams, with regard to a polyester resin B 100 pts.mass. The polyester resin B includes a polybutylene terephthalate copolymer resin (B1), a homogeneous PBT-based mixed resin (B2) containing homogeneous PBT, or a copolymerized PBT-based mixed resin (B3) containing copolymerized PBT.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a laser-welded body having a configuration in which two members made of a polybutylene terephthalate-based material are integrally joined by laser welding.

  In laser welding, the overlapping portion of two resin members is irradiated with a laser beam in the thickness direction of the resin member, the laser beam passes through one of the resin members, and the resin member is melted near the boundary of the resin members In this method, a molten pool is formed between the members, and the molten pool is cooled and solidified to bond the resin members.

  Such laser welding not only enables efficient joining without using joining parts or adhesives, but also allows joining of members with complicated shapes to be performed easily, and because it is localized heating, the thermal effect on the peripheral portion is Is very small, can be joined without causing damage by vibration, it can be joined with high bond strength and high airtightness, so it is widely used in joining of automobile parts and electric / electronic parts etc. It is done.

  With regard to this type of laser welding, for example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-112127), laser light transmitting and absorbing containing 0.001 to 0.3% by weight of a coloring agent consisting only of nigrosine and a thermoplastic resin The molded member and the laser-absorptive molded member containing 0.1 to 5% by weight of another coloring agent containing nigrosine and / or carbon black and a thermoplastic resin are overlapped by the irradiation of the laser beam. There is disclosed a laser-welded body welded and integrated by heat generation.

  Further, Patent Document 2 (Japanese Patent Application Laid-Open No. 2013-155277) discloses, as a resin composition used for welding by laser light, (B) Reinforcing filler 5 to 150 per 100 parts by mass of (A) thermoplastic polyester resin. Parts by mass, (C) 0 to 20 parts by mass of impact modifier, (D) 0 to 5 parts by mass of epoxy compound, (E) flow modifier of 0 to 10 parts by mass, and (F) nigrosine, aniline black, Resin for laser welding containing 0.001 to 0.2 parts by mass of one or more laser light absorbing dyes selected from phthalocyanine, naphthalocyanine, porphyrin, perylene, quaterylene, azo dye, anthraquinone, squaric acid derivative and immonium A composition is disclosed.

By the way, polybutylene terephthalate resin is not only excellent in heat resistance, mechanical strength, dimensional stability, electrical properties, oil resistance, solvent resistance, surface gloss, colorability, flame retardancy, etc., but also crystalline. It is a resin widely used in fields such as the electric and electronic fields and automotive fields because it has a high rate of formation, good fluidity, and excellent formability.
However, polybutylene terephthalate resin has a relatively low laser permeability and is easily warped as compared with polycarbonate resin, polystyrene resin and the like, and therefore has a problem that bonding strength by laser welding tends to be insufficient. It was

  Therefore, with regard to the polybutylene terephthalate-based material used for laser welding, for example, a method of using copolymerized polybutylene terephthalate (Patent Document 3 (Japanese Patent No. 3510817)), and alloying polycarbonate resin or styrene resin with polybutylene terephthalate Methods (Patent Document 4 (Japanese Patent Application Laid-Open No. 2003-292752) and Patent Document 5 (Japanese Patent No. 4641377)) and the like are disclosed.

Further, in Patent Document 6 (Japanese Patent Application Laid-Open No. 2013-155278), it is possible to use polybutylene terephthalate resin, a specific other resin, a specific laser light absorbing dye, and further, if necessary, a reinforcing filler, an epoxy compound, a fluid As a resin composition having excellent moldability and extremely excellent laser welding processability by using a resin composition containing a modifier and the like,
It is a resin composition used for welding by a laser beam, and (A) polybutylene terephthalate resin, and (B) at least one resin selected from (B-1) to (B-5) below (A) And (B) 50 to 95 parts by mass, and (B) 50 to 5 parts by mass, based on 100 parts by mass in total of
Furthermore, with respect to a total of 100 parts by mass of (A) and (B), 0 to 120 parts by mass of (D) reinforcing filler, 0 to 5 parts by mass of (E) epoxy compound, (F) flow modifier (0) to 10 parts by mass and at least one laser light absorbing dye selected from (G) nigrosine, aniline black, phthalocyanine, naphthalocyanine, porphyrin, perylene, quaterrylene, azo dye, anthraquinone, squaric acid derivative and immonium The resin composition for laser welding which contains 0.001-0.2 mass part is disclosed.
(B-1) Polyethylene terephthalate resin (B-2) Polycarbonate resin (B-3) Aromatic vinyl resin (B-4) Acrylic resin (B-5) Polyamide resin

JP 2007-112127 A JP, 2013-155277, A Patent No. 3510817 gazette Unexamined-Japanese-Patent No. 2003-292752 Patent No. 4641377 JP, 2013-155278, A

  As in the above-mentioned Patent Document 1, a laser ray transmitting and absorbing molded member containing a coloring agent consisting only of nigrosine and a laser light absorbing molding member containing a coloring agent containing nigrosine and / or carbon black are subjected to laser welding The laser-welded body integrally formed by welding penetrates the laser light transmitting and absorbing molded member in the thickness direction to form a molten pool from the laser light absorbing molded member to the laser light transmitting and absorbing molded member. Even if there is a gap between the mold and the absorbent molding member, it is filled with the molten resin and can be relatively firmly welded.

  However, in the case where both the laser light transmitting and absorbing molded member and the laser light absorbing molded member are polybutylene terephthalate homopolymers, respectively, warpage is likely to occur, so that the welding strength causes unevenness in welding strength due to the gap generated by the warpage. Even with the laser-welded body having the above-described configuration, there is a problem that it is difficult to increase the welding strength.

  Therefore, in the present invention, when both members are made of a polybutylene terephthalate material, that is, a laser light transmitting and absorbing molded member made of a polybutylene terephthalate material, and a laser light absorbing molded member made of a polybutylene terephthalate material. It is an object of the present invention to provide a new laser-welded body capable of further increasing the bonding strength with respect to a laser-welded body integrally formed by laser welding.

The present invention is a laser-welded body having a configuration in which a member I and a member II are integrally joined.
The member I is a polyester-based resin A and a color material capable of transmitting and absorbing 0.0005 to 5.0 parts by mass of laser light with respect to 100 parts by mass of the polyester-based resin A (“laser light transmission and absorption color material” And the polyester-based resin A is a resin containing a polybutylene terephthalate homopolymer,
The member II is a polyester-based resin B and a color material which can absorb 0.15 to 10.00 parts by mass of laser light with respect to 100 parts by mass of the polyester-based resin B (“laser light absorbing color material”) And a polyester resin B is a resin containing any one of the following (B1), (B2) and (B3):

(B1) Polybutylene terephthalate copolymer resin (B2) Polybutylene terephthalate homopolymer (B2-1) and polybutylene terephthalate copolymer resin, polyethylene terephthalate resin, polycarbonate resin, and aromatic vinyl resin selected from the group consisting of Resin composition containing at least one resin (B2-2) (B3) selected from the group consisting of polybutylene terephthalate copolymer resin (B3-1), polyethylene terephthalate resin, polycarbonate resin and aromatic vinyl resin Resin composition containing at least one resin (B3-2)

  In the laser-welded body proposed by the present invention, the member I contains a laser light transmitting / absorbing color material capable of transmitting and absorbing laser light, and at the time of laser welding, it absorbs and generates heat while transmitting laser light. As the base resin, a polybutylene terephthalate homopolymer capable of making the transmittance of the member I 5 to 90% was selected. On the other hand, the member II contains a laser light absorbing color material that can absorb laser light without transmitting it, and during laser welding, it can absorb laser light, generate heat and melt, and efficiently transmit heat to the member I. Furthermore, in order to reduce the gap between the member I and the member II, it is preferable that the warpage be small, so as polyester resin B which is a base resin of the member II, among the above (B1) (B2) and (B3) The polybutylene terephthalate resin of either was selected. Thus, the warpage is reduced by selecting the material compositions of the members I and II in consideration of the combination of each other, so that the gap between the members I and II is reduced, and the bonding strength is further enhanced. Came to be able to

It is the figure which showed the member I produced by the Example. It is the figure which showed the member II produced by the Example. It is the perspective view which showed an example of the state which laser welds the members I and II produced in the Example. It is explanatory drawing of the measuring method of welding strength in an Example. It is explanatory drawing of the measuring method of curvature in an Example.

  Next, the present invention will be described based on an embodiment. However, the present invention is not limited to the embodiments described below.

[This laser welding body]
In a laser welded body (referred to as "the present laser welded body") according to an embodiment of the present invention, members I and II, which are two members made of a polybutylene terephthalate material, are integrally joined by laser welding. Laser welded body having the following structure.
Since the present laser welded body only needs to have such a configuration, it is optionally possible to have other configurations.
In addition, a polybutylene-terephthalate type material means the material which a polybutylene terephthalate or a polybutylene-terephthalate copolymer occupies 50 mass% or more of the resin component which comprises the material.

<< Member I >>
The member I may be a member molded from a resin composition containing a polyester resin A and a laser light transmitting / absorbing color material capable of transmitting and absorbing laser light.
The member I can appropriately contain components other than the polyester resin A and the laser light transmitting and absorbing color material as described later.

<Polyester resin A>
The polyester resin A preferably contains a polybutylene terephthalate homopolymer (also referred to as "homo PBT").

(Homo PBT)
Homo PBT is a polymer having a structure in which terephthalic acid units and 1,4-butanediol units are ester-linked, and is a polymer composed of terephthalic acid units and 1,4-butanediol units.

The amount of terminal carboxyl groups of homo PBT is preferably 60 eq / ton or less, more preferably 50 eq / ton or less, and still more preferably 30 eq / ton or less.
In addition, 0.5 g of resin is melt | dissolved in benzyl alcohol 25 mL, and the terminal carboxyl group quantity of a polybutylene-terephthalate homopolymer may be calculated | required by titrating using the 0.01 mol / l benzyl alcohol solution of sodium hydroxide. it can.
As a method of adjusting the amount of terminal carboxyl groups, any known method may be used, such as a method of adjusting polymerization conditions such as raw material preparation ratio during polymerization, polymerization temperature, pressure reduction method, and a method of reacting an end blocking agent. It is good.

The intrinsic viscosity of homo PBT is preferably 0.5 to 2.0 dl / g.
If the inherent viscosity is 0.5 dl / g or more, the mechanical strength of the welded body does not become too low, and if it is 2.0 dl / g or less, the flowability decreases and the formability deteriorates. It is possible to prevent the laser weldability from being reduced.
From this point of view, the intrinsic viscosity of homo PBT is preferably 0.5 to 2 dl / g, and more preferably 0.6 dl / g or more or 1.5 dl / g or less, among them 0.7 dl / g or more or 1. More preferably, it is 2 dl / g or less.
The intrinsic viscosity is a value measured at 30 ° C. in a 1: 1 (mass ratio) mixed solvent of tetrachloroethane and phenol.

(Resin that constitutes polyester resin A)
The polyester resin A which comprises the member I may contain "other resin" in the range which does not impair the effect of this invention besides homo PBT. However, it is preferable that homo PBT is a main component resin of polyester resin A which constitutes member I, and it is preferable that homo PBT occupies 50 mass% or more among resins which constitute member I, and more preferably 60 mass% or more Among these, it is more preferable to occupy 70% by mass or more.

When polyester resin A which comprises member I contains "other resin" other than homo PBT, it is necessary to set it as composition different from polyester system resin B which constitutes member II mentioned below. Different composition means that when the kind of resin to be contained is different, even if the kind of resin to be contained is the same but the mixing ratio is different, including the case where the copolymerization component and the copolymerization ratio constituting the resin are different. It is.
Examples of the “other resin” that can be contained in the polyester resin A include copolymerized PBT, polyethylene terephthalate resin, polycarbonate resin, aromatic vinyl resin and the like.

<Laser light transmission and absorption color material>
Examples of the laser light transmitting and absorbing color material contained in the member I include azines such as nigrosine and aniline black, phthalocyanines, naphthalocyanines, porphyrins, quaterylenes, azos, azomethines, anthraquinones, squaric acid derivatives. And immonium, quinacridone, dioxazine, diketopyrrolopyrrole, anthrapyridone, isoindolinone, indanthrone, perinone, perylene, perylene, indigo, thioindigo, quinophthalone, quinoline, triphenyl Mention may be made of various organic dyes and pigments such as methane. One of these may be selected and used, or two or more may be used in combination.
In the present invention, "dye and pigment" means a dye or a pigment.

  Among the above, the laser light transmitting / absorbing color material contained in the member I is a dye / pigment (X) mainly absorbing at the laser light wavelength and a dye / pigment mainly transmitting the laser light in order to increase the degree of blackness It is preferable to use it in combination with Y).

The dye / pigment (X) mainly absorbing at the laser light wavelength preferably includes a condensation mixture of azine compounds having an azine (Azine) skeleton.
Nigrosine is preferred as a condensation mixture of an azine compound having an azine skeleton.
Nigrosine acts as a dye having pigment absorption of laser light and has moderate absorption in the range of laser light of 800 nm to 1200 nm.

Nigrosine is a C.I. I. Solvent Black 5 or C.I. I. As Solvent Black 7, it is a black azine condensation mixture as described in Color Index.
Nigrosine can be synthesized, for example, by oxidation and dehydration condensation of aniline, aniline hydrochloride and nitrobenzene in the presence of iron chloride at a reaction temperature of 160 to 190 ° C. As a commercial product of nigrosine, for example, "NUBIAN (registered trademark) BLACK series" (trade name, manufactured by Orient Chemical Industries, Ltd.) and the like can be mentioned.

On the other hand, examples of the dye (Y) that mainly transmits laser light include anthraquinone dye, perinone dye and azomethine dye.
These dyes and pigments are determined by the absorption wavelength of light, but in order to increase the degree of blackness, specifically, dyes and pigments exhibiting blue (hereinafter sometimes referred to as blue dyes) exhibit yellow color. A combination of a dye / pigment (hereinafter sometimes referred to as yellow dye) and a dye / pigment exhibiting red color (hereinafter sometimes referred to as red dye), a dye / pigment exhibiting purple color (hereinafter sometimes referred to as purple dye) And combinations of yellow dyes, dyes and pigments exhibiting a green color (hereinafter sometimes referred to as green dyes), red dyes, blue dyes and dyes and pigments exhibiting a brown color (hereinafter sometimes referred to as brown dyes) A combination of dyes and pigments can be mentioned.

Preferred blue dyes are anthraquinone dye pigments having a maximum absorption wavelength in the range of 590 to 635 nm. Anthraquinone dyes and pigments are usually blue oil-soluble dyes and pigments.
By combining this dye as the laser light transmitting and absorbing color material contained in the member I, for example, the visibility is higher than that of a green anthraquinone dye and pigment, and when combining a black mixed dye and pigment, a red dye By combining a yellow dye, it is possible to obtain a coloring agent exhibiting a black color with high coloring strength.
As the anthraquinone dye and pigment having a maximum absorption wavelength in the range of 590 to 635 nm, it is preferable to further select one having a measured value (decomposition start temperature) of thermogravimetric analyzer TG / DTA in the presence of air of 300 ° C. or more .

Preferred anthraquinone dyes and pigments are C.I. I. Solvent blue 97 (decomposition start temperature 320 ° C.), C.I. I. Solvent Blue 104 (temperature at which decomposition starts 320 ° C.) and the like are exemplified. They may be used alone or in combination of two or more. However, when the compounding amount is large, the molded article tends to bleed easily in a high temperature atmosphere, and the heat-resistant color-changing property tends to be deteriorated.
Examples of commercially available anthraquinone dyes and pigments include "NUBIAN (registered trademark) BLUE series", "OPLAS (registered trademark) BLUE series" (all trade names, manufactured by Orient Chemical Industries, Ltd.), and the like.

As a preferable red dye, a perinone dye pigment having good heat resistance is selected, and a red perinone dye pigment having a maximum absorption wavelength in the range of 460 to 480 nm can be mentioned. Specific examples of such perinone dyes and pigments C2 include C.I. I. Solvent Red 135, 162, 178, 179, etc. can be used. They may be used alone or in combination of two or more. However, when the compounding amount is large, the molded article tends to bleed easily in a high temperature atmosphere, and the heat-resistant color-changing property tends to be deteriorated.
Examples of commercially available products of red perinone dyes and pigments include "NUBIAN (registered trademark) RED series, OPLAS (registered trademark) RED series" (all trade names, manufactured by Orient Chemical Industries, Ltd.) and the like.

As a preferable yellow dye, an anthraquinone dye pigment having good heat resistance is selected, and an anthraquinone dye pigment having a maximum absorption wavelength in the range of 435 to 455 nm is preferable. Anthraquinone dyes and pigments having a maximum absorption wavelength in the range of 435 to 455 nm are usually yellow oil-soluble dyes and pigments.
Specific examples of yellow anthraquinone dyes and pigments are C.I. I. Solvent Yellow 163, C.I. I. Bat Yellow 1, 2, 3, etc. can be used. They may be used alone or in combination of two or more. They may be used alone or in combination of two or more. However, when the compounding amount is large, the molded article tends to bleed easily in a high temperature atmosphere, and the heat-resistant color-changing property tends to be deteriorated. Examples of commercial products of yellow anthraquinone dyes and pigments include "NUBIAN (registered trademark) YELLOW series, OPLAS (registered trademark) YELLOW series" (all trade names, manufactured by Orient Chemical Industries, Ltd.).

  As a preferred brown dye, an azomethine dye is selected. For example, there can be mentioned dyes and pigments containing at least a 1: 1 type azomethine nickel complex represented by the following formula (1).

[In formula (1), R ^{1 to} R ⁸ are the same as or different from each other, and a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a carboxy group, a hydroxy group, amino A group, an alkylamino group, a nitro group or a halogen atom. ]

The alkyl group having 1 to 18 carbon atoms in ^R 1 to R ⁸ in Formula (1), for example, a methyl group, an ethyl group, n- propyl group, i- propyl, n- butyl group, i- butyl , Sec-butyl group, t-butyl group, n-pentyl group, neo-pentyl group, i-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-decyl group And the like are preferably mentioned, and examples of the alkoxy group having 1 to 18 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, and an sec-butoxy group t-Butoxy group, n-pentyloxy group, neo-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group etc. are preferable, and as an alkylamino group , For example, methylamino group, dimethylamino group, ethylamino, can be preferably exemplified a diethylamino etc., a halogen atom, for example F, Cl, Br and the like.

  The azomethine dye used for 1: 1 type azomethine nickel complex can be produced by a known method. For example, it can be obtained by reacting diaminomaleonitrile as shown in the following reaction formula with salicylaldehyde which may have a substituent.

^R 1 in formula (2) to R ⁸ have the same meanings as ^R 1 to R ⁸ in the formula (1).

  By metallizing this azomethine dye with a nickelating agent such as nickel acetate, as shown below, a 1: 1 type azomethine nickel complex is obtained.

^R 1 in the formula (3) to R ⁸ have the same meanings as ^R 1 to R ⁸ in the formula (1).
In the obtained nickel complex, the azomethine dye acts as a chelating four ligand to form a stable complex.

  The 1: 1 type azomethine nickel complex has good fastness such as heat resistance and light resistance and is therefore useful for outdoor members and resin compositions for members exposed to heat, and changes heat during melting during laser welding. Is less likely to occur, and is suitable as a coloring agent for laser welding members.

Specific examples of the 1: 1 type azomethine nickel complex represented by the above-mentioned formula (1) preferably include the compound examples 1 to 7 in the following Table 1 in which R ^{1 to} R ⁸ are as follows.
The azomethine nickel complex used as the above-mentioned laser light transmitting and absorbing color material contained in the member I is not limited to these.

The dye / pigment (Y) mainly transmitting the laser light used as the laser light transmitting / absorbing color material contained in the member I has an anthraquinone dye (C1) having a maximum absorption wavelength in the range of 590 to 635 nm and a maximum absorption wavelength It is preferable to use the perinone dye pigment (C2) which is in the range of 460 to 480 nm and the anthraquinone dye pigment (C3) whose maximum absorption wavelength is in the range of 435 to 455 nm.
Due to the compatibility with the thermoplastic polyester resin A, the hues of nigrosine, which is a dye / pigment (X) absorbing mainly at the laser light wavelength, and the oil-soluble dye / pigment constituting the dye / pigment (Y) mainly transmitting a laser beam Because of the change, in order to obtain a jet-black molded plate suitable as a black color, it is necessary to adjust the proportion of the oil-soluble dye and / or pigment constituting the dye / pigment (Y). Therefore, the content ratio of C1 to C3 is preferably C1: C2: C3 = 24 to 42:24 to 48:22 to 46 (based on a total of 100 parts by mass of C1, C2, and C3) in mass ratio. A further preferable ratio of C1: C2: C3 is 24 to 41:24 to 39:22 to 46.

Furthermore, the dye / pigment (Y) mainly transmitting the laser light used as the laser light transmitting / absorbing color material contained in the member I has a maximum absorption wavelength in the range of 460 to 480 nm, a perinone dye pigment C2 and a maximum absorption wavelength It is preferable that it is a coloring agent which contains the anthraquinone coloring pigment C1 which is the range of 590-635 nm by mass ratio C2 / C1 of both in the ratio of 0.4-2. In consideration of the color developability by the resin composition of the present invention and suppression of bleed out, it is more preferably 0.4 to 1.5, still more preferably 0.6 or more and 1.5 or less.
Other dyes and pigments that may be used in combination include azo dyes, quinacridone dyes, dioxazine dyes, quinophthalone dyes, perylene dyes, perinone dyes (compounds of wavelengths different from C2 described above), isoindolinone dyes, triphenylmethane dyes, Dyes and pigments such as anthraquinone dyes (compounds of wavelengths different from C1 and C3 described above), azomethine dyes and the like can be mentioned. However, it is preferable not to contain nickel.

The content of the laser ray transmitting / absorbing color material is preferably 0.0005 to 5.0 parts by mass with respect to 100 parts by mass of the polyester resin material A. If the content of the laser light transmitting and absorbing color material is 0.0005 parts by mass or more, it is preferable because the resin absorbs and melts the laser light. On the other hand, if the content is 5.0 parts by mass or less, bleed out of the dye and pigment can be suppressed, and the calorific value can be controlled, which is preferable.
From such a viewpoint, the content of the laser light transmitting and absorbing color material is preferably 0.0005 to 5.0 parts by mass with respect to the polyester resin A, and more preferably 0.001 parts by mass or more or 4.0 parts by mass. It is more preferable that the amount is not more than part, and in particular, not less than 0.005 part by mass or not more than 3.0 parts by mass.

As described above, when the dye / pigment (X) mainly absorbing at the laser light wavelength and the dye / pigment (Y) mainly transmitting the laser beam are combined as the laser light transmitting / absorbing color material, the dye / pigment (X It is preferable that it is 0.0005-0.6 mass part with respect to 100 mass parts of polyester-type resin A.
It is preferable that the content of the cleanser (X) mainly absorbing the laser light be 0.0005 parts by mass or more, since the absorbed cleanser is dispersed uniformly and the resin absorbs the laser light and uniformly melts. On the other hand, if the said content is 0.6 mass part or less, since a laser beam is permeate | transmitted and foaming by decomposition | disassembly of resin does not occur easily, it is preferable.
From this point of view, the content of the cleanser (X) to absorb laser light is preferably 0.0005 to 0.6 parts by mass with respect to 100 parts by mass of the polyester resin A, and more preferably 0.001 parts by mass or more More preferably, it is 0.3 parts by mass or less, and more preferably 0.003 parts by mass or more or 0.1 parts by mass or less.

The dye / pigment (Y) is preferably 0.0005 to 5 parts by mass with respect to 100 parts by mass of the polyester resin A.
If the content of the dye / pigment (Y) mainly transmitting the laser light is 5.0 parts by mass or less, it is preferable because bleeding of the dye / pigment hardly occurs.
From such a viewpoint, the content of the dye (Y) mainly transmitting the laser light is preferably 0.0005 to 5 parts by mass with respect to 100 parts by mass of the polyester resin A, and more preferably 0.05 parts by mass More preferably, it is 4 parts by mass or less, and more preferably 0.1 part by mass or more or 3 parts by mass or less.

  The ratio (Y / X) of the dye / pigment (Y) content to the dye / pigment (X) content is preferably 1 to 100, and more preferably 10 or more, 90 or less, and more preferably 20 or more or 80 or less. Is more preferred.

<Other ingredients>
Part I can, if desired, contain various additives. Such additives include, for example, reinforcing fillers, impact modifiers, flow modifiers, adjuvants, dispersants, stabilizers, plasticizers, UV absorbers, light stabilizers, antioxidants, and charge An inhibitor, a lubricant, a mold release agent, a crystallization accelerator, a crystal nucleating agent, a flame retardant, an epoxy compound, etc. can be mentioned.

<Shape of member I>
The shape of the member I is arbitrary. For example, it may be plate-like, rectangular or other complicated shape. For example, it may be a deformed extruded product (rod, pipe, etc.) for end-to-end welding and used, and a molded product with metal insert used for conducting parts, electronic parts etc. requiring high waterproofness and airtightness. It may be.

  The molding method of the member I is also optional. For example, injection molding method, super high speed injection molding method, injection compression molding method, two-color molding method, hollow molding method such as gas assist, molding method using heat insulation mold, molding method using rapid heating mold, foam molding (Including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method, lamination molding method, press molding method, blow molding method, etc. It can be mentioned.

Since the member I needs to transmit the laser beam over its entire thickness, it is not preferable to be too thick. On the other hand, if it is too thin, it is not preferable because the strength of the molded article becomes weak.
From this point of view, the thickness of the bonding portion of the member I to be laser welded is preferably 0.2 mm to 4.0 mm, and more preferably 0.4 mm or more or 3.5 mm or less, and more preferably 0.5 mm or more. More preferably, it is 0 mm or less.

The transmittance of the member I is not limited. However, the higher the transmittance of the member I, the easier it is for the laser light to be transmitted, which tends to increase the bonding strength of the molded product. Therefore, when the transmittance of the member I is measured using a light beam having a wavelength of 940 nm, the member I preferably has a thickness of 1.5 mm or more and preferably 10 to 80%, and more preferably 10 to 70%. Among these, it is particularly preferable that the content is 15% or more or 60% or less, and more preferably 20% or more or 50% or less.
Also, the reflectance of the member I is not limited. However, the lower the reflectance of the member I, the smaller the loss of laser light, and the more laser light tends to be incident on the member I. Therefore, the reflectance of the member I is preferably 1 to 90% at a thickness of 1.5 mm or more of the member I when measured using a light beam having a wavelength of 940 nm, and in particular, 5% or more or 80% or less Among them, 10% or more or 70% or less, and particularly 10% or more or 60% or less is particularly preferable.

<< Parts II >>
The member II may be a member molded from a resin composition containing a polyester resin B and a laser light absorbing color material that can absorb without transmitting the laser light.
The member II can appropriately contain components other than the polyester resin B and the laser light absorbing color material as described later.

<Polyester resin B>
The polyester resin B preferably contains any one of the following (B1), (B2) and (B3).
By containing any of the following (B1), (B2) and (B3) as the polyester resin B of the member II, the warp of the member II can be reduced, and the members I and II at the time of welding can be reduced. The welding strength can be increased because the gap between them can be reduced. In addition, the residual stress of the welded body can also be reduced.

(B1): Polybutylene terephthalate copolymer resin (B2): Homo-PBT mixed resin containing polybutylene terephthalate homopolymer (B3): Copolymer-PBT mixed resin containing polybutylene terephthalate copolymer resin

<(B1) polybutylene terephthalate copolymer resin>
The polybutylene terephthalate copolymer resin (also referred to as “copolymer PBT”) is a polybutylene terephthalate copolymer including other copolymer components other than terephthalic acid units and 1,4-butanediol units.

  Other dicarboxylic acid units other than terephthalic acid include, for example, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-2,2'- Aroma such as dicarboxylic acid, biphenyl-3,3'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, bis (4,4'-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid Aliphatic dicarboxylic acids, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 4,4'-dicyclohexyldicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, dimer acid, etc. Can be mentioned.

  Examples of the diol unit other than 1,4-butanediol include aliphatic or alicyclic diols having 2 to 20 carbon atoms, and bisphenol derivatives. Specific examples thereof include ethylene glycol, propylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, decamethylene glycol, cyclohexane dimethanol, 4,4'-dicyclohexyl hydroxymethane And 4,4′-dicyclohexylhydroxypropane, ethylene oxide adduct diol of bisphenol A, and the like.

From the viewpoint of mechanical properties and heat resistance, the proportion of terephthalic acid in the dicarboxylic acid unit is preferably 70 mol% or more, and more preferably 90 mol% or more.
The ratio of 1,4-butanediol in the diol unit is preferably 70 mol% or more, more preferably 90 mol% or more, and particularly preferably 95 mol% or more.

  Copolymerized PBT has, in addition to the above-mentioned bifunctional monomers, a trifunctional ester such as tricarballylic acid, trimellisinic acid, trimellitic acid or tetrafunctional ester such as pyromellitic acid in order to introduce a branched structure. Or a multifunctional monomer such as glycerin, trimethylolpropane, or a trifunctional or tetrafunctional ester-forming alcohol such as pentaerythritol, or a small amount of a monofunctional compound such as a fatty acid for molecular weight control It can also be done.

  The copolymerized PBT is, in particular, a polybutylene terephthalate resin obtained by copolymerizing polyalkylene glycols (especially, polytetramethylene glycol (PTMG)) as a copolymer component, a dimer acid-copolymerized polybutylene terephthalate resin, in particular isophthalic acid. It is preferable that it is copolymerized polybutylene terephthalate resin.

In the copolymerized PBT copolymerized with polytetramethylene glycol (PTMG), the ratio of the tetramethylene glycol component in the copolymer is preferably 3 to 40% by mass, and in particular, 5% by mass or more or 30% by mass or less Among these, more preferably 10% by mass or more or 25% by mass or less. By setting it as such a copolymerization ratio, it tends to be excellent in the balance of laser welding property and heat resistance, and is preferable.
On the other hand, in the case of a copolymerized PBT copolymerized with a dimer acid, the ratio of the dimer acid component to the total carboxylic acid component is preferably 0.5 to 30 mol% as a carboxylic acid group, and more preferably 1 mol% or more Alternatively, it is more preferably 20 mol% or less, and more preferably 3 mol% or more or 15 mol% or less. By setting it as such a copolymerization ratio, it tends to be excellent in the balance of laser weldability, long-term heat resistance, and toughness, and is preferable.
In the case of a copolymerized PBT obtained by copolymerizing isophthalic acid, the ratio of the isophthalic acid component to the total carboxylic acid component is preferably 1 to 30 mol% as a carboxylic acid group, and more preferably 2 mol% or more It is more preferable that it is 20 mol% or less, and more preferably 3 mol% or more or 15 mol% or less. By setting it as such a copolymerization ratio, it tends to be excellent in the balance of laser weldability, heat resistance, injection moldability, and toughness, and is preferable.
As the copolymerized PBT, a copolymerized PBT obtained by copolymerizing polytetramethylene glycol or a copolymerized PBT obtained by copolymerizing isophthalic acid is particularly preferable from the viewpoint of laser weldability and formability.

The intrinsic viscosity of the copolymerized PBT is preferably 0.5 to 2.0 dl / g.
If the inherent viscosity is 0.5 dl / g or more, the mechanical strength of the welded body does not become too low, and if it is 2.0 dl / g or less, the flowability decreases and the formability deteriorates. It is possible to prevent the laser weldability from being reduced.
From this point of view, the intrinsic viscosity of the copolymerized PBT is preferably 0.5 to 2.0 dl / g, and more preferably 0.6 dl / g or more or 1.5 dl / g or less, among them 0.7 dl / g or more Or it is further more preferable that it is 1.2 dl / g or less.
The intrinsic viscosity is a value measured at 30 ° C. in a 1: 1 (mass ratio) mixed solvent of tetrachloroethane and phenol.

The amount of terminal carboxyl groups of the copolymerized PBT is preferably 60 eq / ton or less.
If the said amount of terminal carboxyl groups is 60 eq / ton or less, generation | occurrence | production of gas can be suppressed at the time of melt molding of a resin composition.
From this viewpoint, the amount of terminal carboxyl groups of the copolymerized PBT is preferably 60 eq / ton or less, more preferably 50 eq / ton or less, and further preferably 30 eq / ton or less.
On the other hand, the lower limit of the amount of terminal carboxyl groups is not particularly limited. Usually, it is 5 eq / ton or more.
The amount of terminal carboxyl groups of the copolymerized PBT can be determined by dissolving 0.5 g of the resin in 25 mL of benzyl alcohol and titrating with a 0.01 mol / l benzyl alcohol solution of sodium hydroxide.
As a method of adjusting the amount of terminal carboxyl groups, any known method may be used, such as a method of adjusting polymerization conditions such as raw material preparation ratio during polymerization, polymerization temperature, pressure reduction method, and a method of reacting an end blocking agent. It is good.

<(B2) Homo PBT-Based Mixed Resin Composition>
The homo PBT-based mixed resin (B2) is at least one resin (B2- selected from the group consisting of homo PBT (B2-1), copolymerized PBT, polyethylene terephthalate resin, polycarbonate resin and aromatic vinyl resin). It is preferable that it is a resin composition which consists of and 2).

(Polybutylene terephthalate homopolymer (B2-1))
The polybutylene terephthalate homopolymer (B2-1) is the same as the polybutylene terephthalate homopolymer (homo PBT) as the polyester resin A.

(Polybutylene terephthalate copolymer resin (B2-2))
The polybutylene terephthalate copolymer resin (B2-2) is the same as the polybutylene terephthalate copolymer resin (B1) described above.

(Polyethylene terephthalate resin (B2-2))
The above-mentioned polyethylene terephthalate resin (also referred to as "PET") is a resin having an oxyethylene oxyterephthaloyl unit consisting of terephthalic acid and ethylene glycol with respect to all the constituent repeating units as a main constituting unit.
Repeating units having a configuration other than oxyethylene oxyterephthaloyl units may be included.

  PET is produced using terephthalic acid or its lower alkyl ester and ethylene glycol as main raw materials. Other acid components and / or other glycol components may be used together as a raw material.

Examples of acid components other than terephthalic acid include phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 1,3 -Phenylenedioxydiacetic acid and structural isomers thereof, dicarboxylic acids such as malonic acid, succinic acid and adipic acid and derivatives thereof, oxy acids such as p-hydroxybenzoic acid and glycolic acid, derivatives thereof and the like can be mentioned. .
Moreover, as diol components other than ethylene glycol, for example, aliphatic glycols such as 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, etc. Alicyclic glycols such as cyclohexanedimethanol, and aromatic dihydroxy compound derivatives such as bisphenol A and bisphenol S can be mentioned.

  PET is a branched component, for example, a trifunctional ester such as tricarballylic acid, trimellisinic acid, trimellitic acid or the like, or an acid having tetrafunctional ester form performance such as pyromellitic acid or glycerin, trimethylolpropane, pentaerythritol etc. And the alcohol having trifunctional or tetrafunctional ester forming ability is preferably copolymerized with 1.0 mol% or less, more preferably 0.5 mol% or less, still more preferably 0.3 mol% or less. May be

The intrinsic viscosity of PET is preferably 0.3 to 1.5 dl / g, and more preferably 0.4 dl / g or more or 1.2 dl / g or less, among them 0.5 dl / g or more or 0.8 dl / g It is more preferable that it is the following.
The intrinsic viscosity of the polyethylene terephthalate resin is a value measured at 30 ° C. in a 1: 1 (mass ratio) mixed solvent of tetrachloroethane and phenol.

The amount of terminal carboxyl groups of PET is preferably 3 to 60 eq / ton.
By setting the amount of terminal carboxyl groups to 60 eq / ton or less, gas is less likely to be generated during melt molding of the resin material, and the mechanical properties of the obtained member for laser welding tend to be improved. By setting the value of 3 eq / ton or more, the heat resistance, the retention heat stability and the hue of the laser welding member tend to be improved, which is preferable.
From this point of view, the amount of terminal carboxyl groups of PET is preferably 3 to 60 eq / ton, more preferably 5 eq / ton or more or 50 eq / ton or less, and further preferably 8 eq / ton or more or 40 eq / ton or less preferable.
The terminal carboxyl amount of the polyethylene terephthalate resin can be determined by dissolving 0.5 g of the polyethylene terephthalate resin in 25 mL of benzyl alcohol and titrating it using a 0.01 mol / L benzyl alcohol solution of sodium hydroxide. It is.
As a method of adjusting the amount of terminal carboxyl groups, any known method may be used, such as a method of adjusting polymerization conditions such as raw material preparation ratio during polymerization, polymerization temperature, pressure reduction method, and a method of reacting an end blocking agent. It is good.

(Polycarbonate resin (B2-2))
The polycarbonate resin (also referred to as "PC") may be a branched thermoplastic polymer or copolymer obtained by reacting a dihydroxy compound or this and a small amount of a polyhydroxy compound with phosgene or a carbonic diester. It is.
The method for producing PC is not particularly limited, and any of those produced by a conventionally known phosgene method (interfacial polymerization method) or a melting method (transesterification method) can be used, but it was produced by a melt polymerization method Polycarbonate resins are preferred from the viewpoint of laser light transmission and laser welding.

  As a raw material dihydroxy compound, an aromatic dihydroxy compound is preferable, and 2,2-bis (4-hydroxyphenyl) propane (that is, bisphenol A), tetramethylbisphenol A, bis (4-hydroxyphenyl) -p-diisopropylbenzene, Hydroquinone, resorcinol, 4, 4- dihydroxy diphenyl etc. are mentioned, Preferably bisphenol A is mentioned. In addition, compounds in which one or more of tetraalkylphosphonium sulfonates are bonded to the above-mentioned aromatic dihydroxy compounds can also be used.

  Among the above, as PC, an aromatic polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane, or 2,2-bis (4-hydroxyphenyl) propane and other aromatic dihydroxy compounds And aromatic polycarbonate copolymers derived from and. Moreover, copolymers, such as a copolymer with the polymer or oligomer which has a siloxane structure, may be sufficient. Furthermore, you may mix and use 2 or more types of polycarbonate resin mentioned above.

The viscosity average molecular weight of PC is preferably 5,000 to 30,000.
If PC having a viscosity average molecular weight of 5000 or more is used, the mechanical strength of the resulting welded body can be maintained, and if it is 30000 or less, the flowability of the resin composition becomes worse and the moldability is deteriorated, It is possible to suppress the decrease in laser weldability.
From this point of view, the viscosity average molecular weight of PC is preferably 5000 to 30000, more preferably 10000 or more or 28000 or less, and still more preferably 14000 or more or 24000 or less.
In addition, the viscosity average molecular weight of PC is viscosity average molecular weight [Mv] converted from the solution viscosity measured at the temperature of 25 degreeC, using a methylene chloride as a solvent.

  The ratio (Mw / Mn) of the mass average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography (GPC) of PC is preferably 2 to 5, and in particular, 2. More preferably, it is 5 or more or 4 or less. If Mw / Mn is too small, the fluidity in the molten state tends to increase and the formability may decrease. On the other hand, when Mw / Mn is excessively large, the melt viscosity tends to increase and to be difficult to form.

  Further, the amount of terminal hydroxyl group of PC is preferably 100 mass ppm or more, more preferably 120 mass ppm or more, still more preferably 150 mass ppm or more, from the viewpoint of thermal stability, hydrolysis stability, color tone, etc. Most preferably, it is 200 mass ppm or more. However, it is usually 1,500 ppm by weight or less, preferably 1300 ppm by weight or less, more preferably 1200 ppm by weight or less, and most preferably 1000 ppm by weight or less. If the amount of terminal hydroxyl groups of the polycarbonate resin is excessively small, the laser permeability tends to be reduced, and the initial hue at the time of molding may be deteriorated. When the amount of terminal hydroxyl groups is excessively large, the retention heat stability and the moist heat resistance tend to be reduced.

(Aromatic vinyl resin (B2-2))
The aromatic vinyl-based resin is a polymer having an aromatic vinyl structure as a main component, and examples of the aromatic vinyl compound include styrene, α-methylstyrene, paramethylstyrene, vinyl toluene, vinyl xylene and the like. it can.
Moreover, the copolymer which copolymerized the other monomer to the aromatic vinyl compound can also be used as aromatic vinyl resin. Representative examples include, for example, acrylonitrile-styrene copolymer (AS resin) obtained by copolymerizing styrene and acrylonitrile, maleic anhydride-styrene copolymer obtained by copolymerizing styrene and maleic anhydride (maleic anhydride modified Polystyrene resin) can be mentioned.
Typical aromatic vinyl resins are, for example, polystyrene (PS), acrylonitrile-styrene (AS), methyl methacrylate-styrene (MS), styrene-maleic acid copolymer and the like.

  A rubber component can be copolymerized with the aromatic vinyl resin. Examples of rubber components include conjugated diene hydrocarbons such as butadiene, isoprene and 1,3-pentadiene. When the rubber component is copolymerized, the amount of the rubber component to be copolymerized is 1% by mass or more and less than 50% by mass in all the segments of the aromatic vinyl resin. The amount of the rubber component is preferably 3 to 40% by mass, more preferably 5 to 30% by mass.

  Examples of the rubber component copolymerized aromatic vinyl resin include rubber-modified polystyrene (HIPS), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-acrylic rubber copolymer, methyl methacrylate-butadiene-styrene (MBS), acrylonitrile -Styrene-acrylic acid (ASA), styrene-butadiene copolymer (SBS), and its hydride (SEBS), styrene-isoprene copolymer (SIS), and its hydride (SEPS) can be mentioned. .

  Other copolymerizable monomers include, for example, α, β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid, methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, and cyclohexyl methacrylate α , Β-unsaturated carboxylic esters, α, β-unsaturated dicarboxylic anhydrides such as maleic anhydride, itaconic anhydride, etc., N-phenyl maleimide, N-methyl maleimide, N-t-butyl maleimide etc. α And imide compounds of .beta.-unsaturated dicarboxylic acid.

As an aromatic vinyl resin, it is preferable that the mass mean molecular weights measured by GPC are 50000-500000.
If the said molecular weight is 50000 or more, a bleed-out can be suppressed and the fall of the weld strength by the decomposition gas generation | occurrence | production at the time of shaping | molding can be suppressed. On the other hand, if the molecular weight is 500000 or less, the flowability and the laser welding strength can be enhanced.
From this point of view, as the aromatic vinyl-based resin, the mass average molecular weight measured by GPC is preferably 50000 to 500,000, more preferably 100,000 or more, or 400000 or less, and further preferably 150,000 or more, or 300000 or less.

In the case of an acrylonitrile-styrene copolymer, the aromatic vinyl-based resin preferably has a melt flow rate (MFR) of 0.1 to 50 g / 10 min measured at 220 ° C. and 98N.
If the MFR is 0.1 g / 10 min or more, the compatibility with the polybutylene terephthalate resin is good, and appearance defects such as delamination can be suppressed during injection molding. On the other hand, if the said MFR is 50 g / 10 minutes or less, the fall of impact resistance can be suppressed.
From this point of view, the melt flow rate (MFR) of the aromatic vinyl resin is preferably 0.1 to 50 g / 10 min, and more preferably 0.5 g / 10 min or more or 30 g / 10 min or less, among them More preferably, it is 1 g / 10 minutes or more or 20 g / 10 minutes or less.

When the aromatic vinyl resin is polystyrene, the MFR measured at 200 ° C. and 48 N is preferably 1 to 50 g / 10 min, and more preferably 3 g / 10 min or more or 35 g / 10 min or less. Among them, more preferably 5 g / 10 minutes or more or 20 g / 10 minutes or less.
When the aromatic vinyl-based resin is butadiene rubber-containing polystyrene, the MFR measured at 200 ° C. and 49 N is preferably 0.1 to 40 g / 10 min, and more preferably 0.5 g / 10 min or more or 30 g / hr. More preferably, it is 10 minutes or less, and more preferably 0.8 g / 10 minutes or more or 20 g / 10 minutes or less.

(Homo PBT + copolymerized PBT)
When the homo PBT-based mixed resin (B2) contains the homo PBT (B2-1) and the copolymerized PBT (B2-2), the content ratio of the copolymerized PBT (B2-2) is the same as that of the homo PBT (B2-2). It is preferable that it is 10-90 mass% in a total of 100 mass% of 1) and copolymerization PBT (B2-2).
If the said content rate of copolymerized PBT (B2-2) is 10 mass% or more, since laser welding performance becomes high, it is preferable, and if the said content rate is 90 mass% or less, since moldability will improve, it is preferable.
From this point of view, the content ratio of the copolymerized PBT (B2-2) is preferably 10 to 90 mass% in the total 100 mass% of the homo PBT (B2-1) and the copolymerized PBT (B2-2), It is more preferable that it is 15 mass% or more or 85 mass% or less among these, and 20 mass% or more or 80 mass% or less among them.

(Homo PBT + PET)
When the homo PBT-based mixed resin (B2) contains homo PBT (B2-1) and PET (B2-2), the content ratio of PET (B2-2) is equal to that of homo PBT (B2-1) and PET It is preferable that it is 5-50 mass% in a total of 100 mass% of (B2-2).
If the said content rate of PET (B2-2) is 5 mass% or more, since laser welding performance becomes high, it is preferable, and if the said content rate is 50 mass% or less, since moldability will improve, it is preferable.
From this point of view, the content of PET (B2-2) is preferably 5 to 50% by mass, and more preferably 10% by mass in 100% by mass of the total of homo PBT (B2-1) and PET (B2-2). More preferably, it is 45% by mass or less, and more preferably 15% by mass or more or 40% by mass or less.

(Homo PBT + PC)
When the homo PBT mixed resin (B2) contains homo PBT (B2-1) and PC (B2-2), the content ratio of PC (B2-2) is equal to that of homo PBT (B2-1) and PC (B2). It is preferable that it is 5-50 mass% in a total of 100 mass% of B2-2).
If the said content rate of PC (B2-2) is 5 mass% or more, since laser welding performance becomes high, it is preferable, and if the said content rate is 50 mass% or less, since moldability will become good, it is preferable.
From this point of view, the content of PC (B2-2) is preferably 5 to 50% by mass, and more preferably 10% by mass in 100% by mass of the total of homo PBT (B2-1) and PC (B2-2). More preferably, it is 45% by mass or less, and more preferably 15% by mass or more or 40% by mass or less.

(Homo PBT + aromatic vinyl resin)
When the homo PBT mixed resin (B2) contains homo PBT (B2-1) and aromatic vinyl resin (B2-2), the content ratio of the aromatic vinyl resin (B2-2) is equal to that of homo PBT The total amount of (B2-1) and the aromatic vinyl resin (B2-2) is preferably 5 to 50% by mass in 100% by mass.
If the said content rate of aromatic vinyl-type resin (B2-2) is 5 mass% or more, since laser welding performance becomes high, it is preferable, and if the said content rate is 50 mass% or less, since moldability will become good. preferable.
From this viewpoint, the content ratio of the aromatic vinyl resin (B2-2) is 5 to 50 mass% in the total 100 mass% of the homo PBT (B2-1) and the aromatic vinyl resin (B2-2). Among these, 10 mass% or more or 45 mass% or less is preferable, and 15 mass% or more or 40 mass% or less is more preferable among them.

In addition, the preferable content rate at the time of combining homo PBT (B2-1) and one in copolymerization PBT, PET, PC, and an aromatic vinyl-type resin (B2-2) was described. However, a plurality of types may be used by appropriately selecting from the above (B2-2), and the content ratio of each case in that case makes the homo PBT and / or the copolymerized PBT 50% by mass or more of the whole, And it is preferable that the sum total does not exceed 100 mass% in each ratio range of above-mentioned (B2-2).
For example, in the case where an aromatic vinyl resin and PC are used in combination as (B2-2), a total of 50% by mass or more of homo PBT, 5 to 50% by mass of an aromatic vinyl resin, and 5 to 50% by mass PC It is preferable to make 100 mass%.
Moreover, also in (B3) mentioned later, when using multiple types from (B3-2), it can combine in the same way of thinking as the above.

<(B3) Copolymerized PBT-Based Mixed Resin Composition>
The copolymerized PBT-based mixed resin (B3) contains a copolymerized PBT (B3-1) and at least one resin (B3-2) selected from the group consisting of PET, PC and an aromatic vinyl resin It is preferable that it is a resin composition.

At this time, the copolymerized PBT (B3-1) in the copolymerized PBT-based mixed resin (B3) is the same as the copolymerized PBT (B2-2) in the homo-PBT-based mixed resin (B2).
Further, PET, PC and aromatic vinyl resin in the copolymerized PBT mixed resin (B3) are the same as PET, PC and aromatic vinyl resin in the homo PBT mixed resin (B2), respectively.

(Copolymerized PBT + PET)
When the copolymerized PBT-based mixed resin (B3) contains the copolymerized PBT (B3-1) and the PET (B3-2), the content ratio of the PET (B3-2) is the copolymerized PBT (B3-1). It is preferable that it is 50 mass% or less in total 100 mass% of PET) and PET (B3-2).
If the said content rate of PET (B3-2) is 50 mass% or less, since it is excellent in a moldability, it is preferable.
From this viewpoint, the content ratio of PET (B3-2) is preferably 50% by mass or less, and more preferably 5% by mass or less in 100% by mass in total of the copolymerized PBT (B3-1) and PET (B3-2). More preferably, the content is 40% by mass or less, and more preferably 5% by mass or more or 30% by mass or less.

(Copolymerized PBT + PC)
When the copolymerized PBT-based mixed resin (B3) contains the copolymerized PBT (B3-1) and the PC (B3-2), the content ratio of PC (B3-2) is the copolymerized PBT (B3-1). It is preferable that it is 50 mass% or less in a total of 100 mass% of PC) and PC (B3-2).
If the content rate of PC (B3-2) is 50 mass% or less, since it is excellent in moldability, it is preferable.
From this viewpoint, the content of PC (B3-2) is preferably 50% by mass or less, and more preferably 5% by mass or less in 100% by mass of the total of the copolymerized PBT (B3-1) and PC (B3-2). More preferably, the content is 40% by mass or less, and more preferably 5% by mass or more or 30% by mass or less.

(Copolymerized PBT + aromatic vinyl resin)
When the copolymerized PBT mixed resin (B3) contains the copolymerized PBT (B3-1) and the aromatic vinyl resin (B3-2), the content ratio of the aromatic vinyl resin (B3-2) is The total amount of the copolymerized PBT (B3-1) and the copolymerized PBT (B3-1) is preferably 50% by mass or less.
If the said content rate of aromatic vinyl-type resin (B3-2) is 50 mass% or less, since it is excellent in a moldability, it is preferable.
From this viewpoint, the content of the aromatic vinyl resin (B3-2) is 50% by mass or less in 100% by mass in total of the copolymerized PBT (B3-1) and the copolymerized PBT (B3-1). Among them, the content is preferably 5% by mass or more and 45% by mass or less, and more preferably 5% by mass or more and 40% by mass or less.

<Resin that constitutes polyester resin B>
The polyester resin B which comprises the member II may contain "other resin" in the range which does not impair the effect of this invention other than above-mentioned (B1), (B2), or (B3). However, (B1), (B2) or (B3) described above is preferably the main component resin of the polyester resin B constituting the member II, and among the resins constituting the member II (B1), (B2) Alternatively, (B3) preferably accounts for 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more.

When polyester resin B which comprises member II contains said "other resin", it is necessary to set it as the composition different from polyester-based resin A which comprises member I mentioned above. Different composition means that when the kind of resin to be contained is different, even if the kind of resin to be contained is the same but the mixing ratio is different, including the case where the copolymerization component and the copolymerization ratio constituting the resin are different. It is.
As "other resin" which polyester resin B may contain, homo PBT, copolymer PBT, polyethylene terephthalate resin, polycarbonate resin etc. can be mentioned, for example.

<Laser light absorbing color material>
Examples of the laser light-absorbing color material contained in the member II include black colorants such as carbon black, white colorants such as titanium oxide and zinc sulfide, and the like, and at least one or two of them may be mentioned. The above can be used in combination. Among them, those containing carbon black are preferable.

As carbon black, for example, at least one or two or more of furnace black, thermal black, channel black, lamp black and acetylene black can be used in combination.
It is also preferable to use carbon black that has been previously masterbatched to facilitate dispersion.

The primary particle diameter of carbon black is preferably 10 nm to 30 nm from the viewpoint of dispersibility, and more preferably 15 nm or more or 25 nm or less. When the dispersibility is good, welding unevenness at the time of laser welding is reduced.
Further possible, carbon black, from the viewpoint of jet-blackness, preferably has a nitrogen adsorption specific surface area measured is 30 to 400 m ² / g with JIS K6217, among them ^{50 m} 2 / g or more and ^{80 m} 2 / g or more among them Is more preferred.

Furthermore, carbon black, from the viewpoint of dispersibility, it is preferable that the DBP absorption as measured by JIS K6221 is 20~200cm ³ / 100g, among them 40 cm ^3/100 g or more or 170cm ^3/100 g or less, 50 cm ³ among them it is further preferred / 100g or more or 150cm is ³ / 100g or less. When the dispersibility is good, welding unevenness at the time of laser welding is reduced.

The content of the laser light absorbing color material is preferably 0.15 to 10.00 parts by mass with respect to 100 parts by mass of the polyester resin B.
If the content of the laser light absorbing color material is 0.15 parts by mass or more, the resin generates heat and melts at the time of laser irradiation, and if the content is 10.00 parts by mass or less, the heat is rapidly and excessively generated. It is preferable because it can prevent the decomposition of the resin.
From this point of view, the content of the laser light absorbing color material is preferably 0.15 to 10.00 parts by mass with respect to 100 parts by mass of the polyester resin B, and in particular, 5 parts by mass or less and 1 part by mass or less Is more preferred.

  The member II may or may not contain the laser light transmitting and absorbing color material, for example, nigrosine. When the member II does not contain the laser light transmitting and absorbing color material, particularly nigrosine, it is possible to prevent heat resistant discoloration and weather resistant discoloration.

<Other ingredients>
Part II can, if desired, contain various additives. Such additives include, for example, reinforcing fillers, impact modifiers, flow modifiers, adjuvants, dispersants, stabilizers, plasticizers, UV absorbers, light stabilizers, antioxidants, and charge An inhibitor, a lubricant, a mold release agent, a crystallization accelerator, a crystal nucleating agent, a flame retardant, an epoxy compound, etc. can be mentioned.

<Shape of member II>
The shape of the member II is arbitrary. For example, it may be plate-like, rectangular, box-like, or any other complicated shape. For example, it may be a deformed extruded product (rod, pipe, etc.) for end-to-end welding and used, and a molded product with metal insert used for conducting parts, electronic parts etc. requiring high waterproofness and airtightness. It may be.

  The method of molding the member II is also optional. For example, injection molding method, super high speed injection molding method, injection compression molding method, two-color molding method, hollow molding method such as gas assist, molding method using heat insulation mold, molding method using rapid heating mold, foam molding (Including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method, lamination molding method, press molding method, blow molding method, etc. It can be mentioned.

The transmittance of the member II is preferably 10% or less at a thickness of 1.5 mm or more, in the case of measurement using a light beam having a wavelength of 940 nm, from the viewpoint of enhancing the manufacturing efficiency and welding strength of the welded body. It is particularly preferable that the content is 5% or less, particularly 0%.
Further, the reflectance of the member II is not particularly limited.

<Relationship between member I and member II>
From the viewpoint of welding strength and pressure resistance, regarding the relationship between the member I and the member II, the difference ((Tm-A)-(Tc-A)) between the melting point Tm-A of the member I and the crystallization temperature Tc-A is More preferably, the difference is larger than the difference between the melting point Tm-B of the member II and the crystallization temperature Tc-B ((Tm-B)-(Tc-B)). In particular, although the resin used for the absorption side member is strongly affected, the difference between the two (((Tm-A)-(Tc-A))-((Tm-B)-(Tc-B)), "member I -(A difference of (Tm-Tc) of the member II) is preferably 0 to 30 ° C, more preferably 2 ° C or more or 20 ° C or less, and more preferably 3 ° C or more or 15 It is more preferable that the temperature is not higher than ° C, and more preferably not lower than 4 ° C or not higher than 10 ° C.
In order to do so, for example, adjustment of the mixing ratio of polyester resin B used for member II, selection of various additives and adjustment of compounding amount, selection of laser light transmitting dye and pigment of polyester resin A used for member I And what is necessary is just to adjust a compounding quantity etc. However, it is not limited to these adjustment methods.

Further, from the viewpoint of welding strength and pressure resistance, the melting enthalpy ΔHm-A of the member I and the melting enthalpy ΔHm-B of the member II are the same as the melting enthalpy ΔHm-A of the member I and the melting enthalpy ΔHm− of the polyester resin B. More preferably, it is higher than B. The difference (ΔHm-A)-(ΔHm-B) between the melting enthalpy ΔHm-A of the member I and the melting enthalpy ΔHm-B of the member II is preferably 0 to 20 J / g, and more preferably 0.5 J / g or more Or it is further more preferable that it is 10 J / g or less, and it is further more preferable that it is 2 J / g or more or 9 J / g or less among these.
In order to do so, for example, adjustment of the mixing ratio of polyester resin B used for member II, selection of various additives and adjustment of compounding amount, selection of laser light transmitting dye and pigment of polyester resin A used for member I And what is necessary is just to adjust a compounding quantity. However, it is not limited to these adjustment methods.
The melting point Tm, the crystallization temperature Tc and the melting enthalpy ΔHm are measured by cutting out a sample from a point at which the distance between the member I and the member II molded by injection molding from the gate of the injection molding die is 5 mm or more Is preferred.

[Method of producing the present laser welded body]
The manufacturing method of the member I or the member II may respectively produce a resin composition by a normal method, and should just shape | mold a resin composition by a normal method.
For example, the raw materials constituting the member I or II may be mixed and melt-kneaded using a single screw or twin screw extruder. Alternatively, the resin composition may be prepared without mixing each component in advance, or mixing only a part thereof in advance, supplying it to an extruder using a feeder, and melt-kneading it.

Moreover, what melt-kneaded what mix | blended a part of other resin with one part resin of the member I or II prepares a masterbatch, and mix | blends the remaining resin and another component with this, and it melts You may knead | mix.
In addition, when using fibrous reinforcement fillers, such as glass fiber, it is also preferable to supply from the side feeder in the middle of the cylinder of an extruder.

  The heating temperature at the time of melt-kneading can be suitably selected from the range of normally 220-300 degreeC. If the temperature is too high, decomposition gas is likely to be generated, which may cause opacification. Therefore, it is desirable to select a screw configuration considering shear heat generation and the like. The use of an antioxidant and a heat stabilizer is desirable in order to suppress decomposition during kneading and molding during the later process.

Arbitrary methods can be adopted as a method of molding the members I and II.
For example, injection molding method, super high speed injection molding method, injection compression molding method, two-color molding method, hollow molding method such as gas assist, molding method using heat insulation mold, molding method using rapid heating mold, foam molding (Including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method, lamination molding method, press molding method, blow molding method, etc. It can be mentioned.

Next, the member I and the member II are overlapped, arranged so that the member I side is the light source side of the laser light, and a pressing force is applied inward from both sides in the thickness direction. A laser beam may be emitted.
The irradiated laser light penetrates the member I in the thickness direction to form a longitudinally long molten pool up to the member II, and by cooling and solidifying the molten pool, the member I and the member II can be joined. .
When the members I and II are stacked, for example, surface contact or butt contact can be made.
Preferred laser welding conditions are described in detail below.

(Laser welding conditions)
Next, preferable laser welding conditions will be described. However, it is not the meaning limited to welding conditions explained below.

  As the laser welding conditions, it is preferable to appropriately select preferable conditions depending on, for example, the combination of the specification of the apparatus, the laser type, the laser diameter, the laser output, and the scanning speed.

As a kind of laser beam to irradiate, a solid state laser, a fiber laser, a semiconductor laser, a gas laser, a liquid laser etc. can be mentioned, for example. For example, YAG (yttrium aluminum garnet crystal) laser (wavelength 1064 nm, 1070 nm), LD (laser diode) laser (wavelength 808 nm, 840 nm, 940 nm, 980 nm) or the like can be preferably used. Among them, laser light having a wavelength of 940 nm, 980 nm, or 1070 nm is preferable.
The oscillation mode may be CW or pulse.
The irradiation method is also not particularly limited. For example, it is possible to appropriately select from a method of moving a laser head by a robot, a galvano scan method in which laser light is reflected by a mirror and scanning, a plurality of laser heads are equipped, and a welding surface is simultaneously irradiated.

The laser spot diameter is preferably 0.1 mm to 30 mm, more preferably 0.2 mm to 10 mm, and still more preferably 0.7 mm to 3.0 mm.
If the laser spot diameter is 0.1 mm or more, welding for obtaining a desired welding strength can be easily performed, and if it is 30 mm or less, the welding width can be easily controlled. The spot diameter of the laser beam can be selected in accordance with the width and height of the welding surface.
Further, the laser light may be focused on the bonding surface or may be defocused, and it is preferable to appropriately select the laser light in accordance with the welding object to be obtained.

The laser output is preferably 1 W to 1000 W, more preferably 10 W or more or 500 W or less, and more preferably 15 W or more or 200 W or less.
If the laser output is 1000 W or less, it can be suppressed that the laser welding equipment cost becomes too high, and if it is 1 W or more, it becomes easy to obtain sufficient welding strength.
The laser scanning speed is preferably 0.1 mm / s to 20000 mm / s, more preferably 1 mm / s or more and 10000 mm / s or less, and still more preferably 10 mm / s or more or 1000 mm / s or less.
With regard to the laser scanning method, in view of welding efficiency, welding strength, welding appearance and apparatus load, the laser output, welding scheduled line, scanning speed, and / or scanning method are adjusted according to the shape of the joint surface. Is preferred.

When performing laser welding, first, the member I and the member II are overlapped, and the state in which the member I and the member II are overlapped is maintained. When the overlapped state is maintained, a transparent plate such as a glass plate, a quartz plate or an acrylic plate may be disposed on the transmission side member I, that is, on the laser irradiation side. In particular, when a glass plate or a quartz plate is disposed, it is suitable for promoting the heat radiation of the heat generated at the time of laser welding to obtain a good appearance.
Next, a laser beam is scanned and irradiated from the upper side of the member I onto a planned welding position corresponding to the peripheral edge of the member II. At this time, most or most of the laser light transmits and partially absorbs the member I. Then, the laser beam is absorbed by the bonding surface of the member I and the member II, and the vicinity of the surface of the bonding surface generates heat and melts.
By doing this, the joint surface of the member II and the member I melt together, and after the irradiation of the laser beam is stopped, the melted portions of the member I and the member II are cooled and solidified, and both members are high It can be welded and integrated with strength.

At this time, at the time of joining of at least both members by laser welding, it is preferable to apply a pressing force (N / mm) to both members by a jig or pressing means.
The pressing force (N / mm) is preferably 0.0002 N / mm or more and 160 N / mm or less, in particular 80 N / mm or less, in particular 50 N / mm or less, in particular 40 N / mm or less, among them 30 N / mm It is particularly preferable that the diameter is equal to or less than mm, and more preferably 20 N / mm or less. By applying a pressing force in this range, residual stress is less likely to remain in the molded product, warpage deformation becomes smaller, and sufficient welding strength can be easily obtained.
On the other hand, the lower limit is preferably 0.4 N / mm or more. By setting the density to 0.4 N / mm or more, the adhesion of the joint surface can be easily maintained sufficiently, and the welding can be sufficiently performed.
However, when welding a member having a long laser scanning distance, for example, a member having a laser scanning distance of 200 mm or more, the pressing force (N / mm) is preferably 10 N / mm or less, particularly 9 N / mm. It is preferably mm or less, more preferably 5 N / mm or less, and most preferably 3 N / mm or less.

The above-mentioned pressing force (N / mm) is a pressing force per unit distance, and as an example, a coin-type load cell (Co., Ltd.) mounted on a pressing stage attached with a pressing cylinder (SMC air cylinder (φ 100 mm)) Imada, LM-20M) is set, and the actual pushing force (N) is measured. Then, a value obtained by dividing the obtained actual pressing force (N) by the length (mm) of one circumference of the welding scheduled line can be obtained as the pressing force per unit distance (N / mm).
By the above, the joint surface of the member II and the member I melt together, and after the irradiation of the laser beam is stopped, the melted portions of the member I and the member II are cooled and solidified to be both members. It can be welded and integrated with high strength.

The welding strength of the present laser-welded body (welding conditions in the case of the following cup shape: pushing force: 4.92 N / mm.) Is preferably 500 N or more, more preferably 550 N or more, still more preferably 600 N or more It is.
In addition, the pressure resistance strength of the present laser welded body (welding conditions for the following cup shape: pressing force 15.8 N / mm.) Is preferably 400 kPa or more, more preferably 600 kPa or more, and more The pressure is preferably 800 kPa or more, more preferably 850 kPa or more, and particularly preferably 1000 kPa or more.
In addition, in the measurement of the said various strength, a test piece decides to use the thing of the magnitude | size which can be welded by the pushing force described.

(Welding conditions)
Laser welding machine; Fine device FD-2330
Wavelength 940 nm
Output: 140 W
Spot diameter: 2.1 mmφ
Scanning speed: 93 mm / s
Irradiation energy: 1.51 J / mm
Scanning distance: 137 mm

  The shape, size, thickness and the like of the present laser-welded article are arbitrary, and can be used for various applications. For example, there may be mentioned electric parts for transportation equipment such as automobiles, electric and electronic parts, parts for industrial machinery, and other parts for household use. Among them, welding strength is high and pressure resistance is also high. It is particularly preferable to use for applications requiring airtightness, such as containers for incorporating electric and electronic components such as circuits, sensors, solenoids, motors, transformers, and batteries.

<Explanation of the phrase>
In the present specification, when expressing as “X to Y” (X and Y are arbitrary numbers), “preferably greater than X” or “preferably Y” with the meaning of “X or more and Y or less” unless otherwise stated. Also includes the meaning of "smaller".
Also, when expressed as “X or more” (X is an arbitrary number) or “Y or less” (Y is an arbitrary number), “greater than X is preferable” or “preferably less than Y” It also includes the intention.

  Hereinafter, the present invention will be described in more detail based on examples.

<Optical characteristics: Measurement of transmittance and reflectance>
Resin composition pellets obtained in the following Examples and Comparative Examples, that is, resin composition pellets for forming member I shown in Table 3 below or resin composition pellets for forming member II shown in Table 4 below After drying at 120 ° C. for 7 hours, using an injection molding machine (“NEX 80-9E” manufactured by Nissei Resin Industry Co., Ltd.), the cylinder temperature 260 ° C., the mold temperature 60 ° C., and the following injection conditions: A 60 mm × 60 mm × 1.5 mm thick flat test piece for reflectance measurement was injection molded.

(Injection condition)
Holding time: 15 seconds
Cooling time: 15 seconds
Injection speed: 120 mm / sec
Back pressure: 4MPa
Screw rotation speed: 80 rpm

  Among the test pieces (60 mm × 60 mm × 1.5 mm thick) obtained above, UV visible in the center of the width of the test piece with a width of 10 mm and a length of 20 mm from the point 35 mm from the gate side The transmittance (%) and the reflectance (%) at a wavelength of 940 nm are determined using a near infrared spectrophotometer (“UV-3100 PC” manufactured by Shimadzu Corporation), and the transmittance and the reflectance of the member I and the member II are obtained It showed in the following table.

<Measurement method of color tone>
Resin composition pellets obtained in the following Examples and Comparative Examples, that is, resin composition pellets for forming member I shown in Table 3 below or resin composition pellets for forming member II shown in Table 4 below After drying at 120 ° C. for 7 hours, a cylinder temperature of 260 ° C., a mold temperature of 60 ° C., and the above-mentioned transmittance and reflectance measurement using an injection molding machine (“NEX 80-9E” manufactured by Nissei Resin Co., Ltd. A 60 mm × 60 mm × 3 mm thick flat test piece for color tone measurement was injection molded under the same injection conditions as when the test piece was molded.
L * value (SCE) was measured about the flat test piece obtained above, and it showed in the following table as L ^* value of member I or II. The measurement is performed using a spectrometric color difference meter (CM-3600 d, manufactured by Konica Minolta Optics Co., Ltd.) conforming to ISO 7724/1, D65 / 10 (reflected illumination · 10 ° direction light reception), SCE (regular reflection light removal) colorimetry It measured using the target mask CM-A ((phi) 8 mm) by the method.

<Method of measuring warpage>
Resin composition pellets obtained in the following Examples and Comparative Examples, that is, resin composition pellets for forming member I shown in Table 3 below or resin composition pellets for forming member II shown in Table 4 below After drying at 120 ° C. for 7 hours, using the “Model SE-50D” injection molding machine manufactured by Sumitomo Heavy Industries, Ltd., using a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C., the rectangular solid shown in FIG. A box-shaped compact was molded.
FIG. 5 is a perspective view of a box-shaped molded body used for evaluation of warpage, showing a state in which the bottom surface is down. The box-shaped molded product is 25 mm wide, 30 mm long and 25 mm high, the wall thickness is 1 mm at the bottom, and the other side is 0.5 mm. The gate is a substantially elliptical one-point gate with a major axis of 2.0 mm and a minor axis of 1.5 mm, and is a submarine gate (GATE in FIG. 5) at the center of the front side of FIG.

Place the molded product after molding so that the bottom of the box faces down, and measure the inward camber length L at the top of the far side when the inward side of the far side in Figure 5 is warped inwards (unit: The warpage of the member I or II is shown in the table below.
The smaller this value is, the smaller the amount of inward warpage of the molded product is, and the better the dimensional accuracy is.

<Method of measuring melting point Tm, crystallization temperature Tc, melting enthalpy ΔHm>
The resin composition pellets obtained in the following Examples and Comparative Examples, that is, the resin composition pellets for forming the member I shown in Table 3 below are dried at 120 ° C. for 7 hours, and then an injection molding machine (Japan Steel Works Ltd. Made with a cylinder temperature of 260 ° C. and a mold temperature of 60 ° C. using a product “J55”) to produce a 1.5 mm thick black or milky white molded member (member I) as shown in FIG. 1 .
A portion to be welded (distance from the gate: 33 mm) of the molded article of the member I produced was cut, and using a differential scanning calorimetry (DSC) machine ("Pyris Diamond" manufactured by Perkin Elmer) under a nitrogen atmosphere, The temperature is raised from 30 ° C. to 300 ° C. at a temperature rising rate of 20 ° C./min, held at 300 ° C. for 3 minutes, and then lowered at a temperature lowering rate of 20 ° C./min to obtain melting point Tm, melting enthalpy ΔHm, crystallization temperature Tc It measured and showed in the following table as Tm of member I, Tc, Tm-Tc, and deltaHm.

<Preparation of member I>
In the preparation of the member I, dyes and pigments in which the components shown in Table 2 were blended in the proportions shown in Table 2 were used.

The components shown in Table 3 below were added to a stainless steel tumbler at the mixing ratio shown in Table 3 and mixed with stirring for 1 hour. The obtained mixture is introduced into the main hopper of a 30 mm vent type twin screw extruder ("TEX 30α" manufactured by Japan Steel Works, Ltd.), glass fiber is supplied from the hopper from the side feeder, and the extruder barrel set temperature is 260 The die was kneaded at 250 ° C., a screw rotation speed of 200 rpm, and a discharge amount of 40 kg / hour, and extruded in a strand form to obtain pellets of a resin composition.
The obtained pellets are dried at 120 ° C. for 7 hours and then molded at a cylinder temperature of 260 ° C. and a mold temperature of 60 ° C. by using an injection molding machine (“J55” manufactured by Japan Steel Works, Ltd.). Such a black or milky white molded article (member I) having a thickness of 1.5 mm was produced.

<Production of member II>
The components shown in Table 4 below were added to a stainless steel tumbler at the mixing ratio shown in Table 4 and mixed with stirring for 1 hour. The obtained mixture is introduced into the main hopper of a 30 mm vent type twin screw extruder ("TEX 30α" manufactured by Japan Steel Works, Ltd.), glass fiber is supplied from the hopper from the side feeder, and the extruder barrel set temperature is 260 The die was kneaded at 250 ° C., a screw rotation speed of 200 rpm, and a discharge amount of 40 kg / hour, and extruded in a strand form to obtain pellets of a resin composition.
The obtained pellets are dried at 120 ° C. for 7 hours and then molded at a cylinder temperature of 260 ° C. and a mold temperature of 60 ° C. by using an injection molding machine (“J55” manufactured by Japan Steel Works, Ltd.). Such a black or milky white molded article (member II) was produced.
The optical properties, color tone, warping amount, melting point Tm, melting enthalpy ΔHm and crystallization temperature Tc were measured in the same manner as described for the member I. With respect to the melting point Tm, the melting enthalpy ΔHm, and the crystallization temperature Tc, the welding planned portion (the distance from the gate: 42 mm) of the molded product of the produced member II was measured.

<Preparation of laser welded body>
Next, select the members I and II of the combination shown in Table 5 and Table 6 below, open the holes 21 and 22 respectively as shown in FIG. 3, and place the jigs 23 and 24 for welding strength measurement inside. In the state in which it is placed, the lid-like member I is superimposed on the box-like member II, and the laser light source is disposed at the vertically upper position of the ridge portion which is the overlapping portion of the member I and the member II. And while applying a pressing force of 4.92 N / mm or 15.8 N / mm inward from both sides in the thickness direction to the overlapping portion of the member II, while scanning the laser under the following conditions 1 A circumferential scan was performed and cooled to obtain a laser-welded body.

The welding conditions are as follows.
Laser welding machine; Fine device FD-2330
Wavelength: 940 nm
Output: 140 W
Spot diameter: 2.1 mmφ
Scanning speed: 93 mm / s
Irradiation energy: 1.51 J / mm
Scanning distance: 137 mm

<Evaluation of welding strength>
As shown in FIG. 4, measuring jigs 25 and 26 are respectively inserted into the upper and lower surfaces of the box consisting of the members I and II, and are respectively coupled with the jigs 23 and 24 housed inside, and pulled vertically. Strength (tensile speed: 5 mm / min), the strength (welding strength) at which the members I and II separate was measured. However, when the member I and the member II were peeled before the test, the test could not be performed (in the table, it was described as not good).
The apparatus used was a 5544 universal tester manufactured by Instron.

<Evaluation of compressive strength>
After a hole of φ 3.5 mm is made at the position of the convex portion at the center of the member I of the welded body welded under a pressing force of 15.8 N / mm, a water injection coupler is joined. First, the inside of the welded body is filled with water and then immersed in water at 25 ° C. Next, water supply to the inside of the weldment is started, the pressure inside the weldment is increased in 196 kPa steps, and the time when pressure is released from the weld (time when pressure is reduced) is taken as the maximum breaking pressure. However, when the member I and the member II were peeled before the test, the test could not be performed (in the table, it was described as not good).
The apparatus used was a "bottle pressure tester" manufactured by Toyo Seiki Co., Ltd.

<Bleed resistant performance>
Place the produced weldment on a PBT homopolymer resin (NOVADURAN® 5010R5 Natural) plate (hereinafter referred to as Natura plate) so that the member II is at the bottom, and place in an oven at 120 ° C. for 8 hours After heating, it was observed whether the color material was transferred to the natural plate in contact with the member II and evaluated according to the following criteria.
○ (good): Bleed out was not observed.
X (poor): Bleed out was observed.

<Reference example>
When welding is performed under the conditions of an output of 50 W, a scanning speed of 15 mm / s, an irradiation energy of 3.33 J / mm, and a pressing force of 15.8 N / mm at welding in the combination of Comparative Example 5, welding is possible The welding strength was 1322 N and the pressure resistance was 814 N. When the scanning time became long, the productivity worsened, and at the same time, many welding burrs were confirmed due to the excessive energy irradiation conditions, and white powder was adhered to the inside of the welded body, and when the internal electronic board etc. were mounted Contamination of the circuit was a concern.

<General consideration>
From the above examples and the results of tests conducted by the present inventors, the member I contains a laser light transmitting / absorbing color material capable of transmitting and absorbing laser light, and at the time of laser welding, the laser light is transmitted while absorbing It is considered that it is preferable that the base resin is a polybutylene terephthalate homopolymer having a transmittance of 5 to 90% because it exothermically melts.

On the other hand, the warpage of the member II is small by selecting the polybutylene terephthalate resin of any of the following (B1), (B2) and (B3) as the polyester resin B which is the base resin of the member II As a result, it was found that the welding strength is increased and the residual stress is reduced because the gap between the members I and II is reduced at the time of welding.
(B1) Polybutylene terephthalate copolymer resin (B2) At least one resin selected from the group consisting of polybutylene terephthalate homopolymer, polybutylene terephthalate copolymer resin, polyethylene terephthalate resin, polycarbonate resin and aromatic vinyl resin Resin composition containing (B3) polybutylene terephthalate copolymer resin, and at least one resin selected from the group consisting of polyethylene terephthalate resin, polycarbonate resin, and aromatic vinyl resin

The member II contains a laser light absorbing color material that can absorb laser light without transmitting it, and absorbs laser light during laser welding to generate heat and melt and transmit heat to the transmitting material. It can be considered that it is preferable that the polybutylene terephthalate resin is any one of B1), (B2) and (B3).
Therefore, a polybutylene terephthalate homopolymer is selected as the base resin of the member I, and any one of the polybutylene terephthalate resins of the above (B1), (B2) and (B3) is selected as the base resin of the member II. It has been found that the bonding strength can be further enhanced.

Claims (6)

A laser-welded body having a configuration in which a member I and a member II are integrally joined,
The member I is a polyester-based resin A and a color material capable of transmitting and absorbing 0.0005 to 5.0 parts by mass of laser light with respect to 100 parts by mass of the polyester-based resin A (“laser light transmission and absorption color material” And the polyester-based resin A is a resin containing a polybutylene terephthalate homopolymer,
The member II is a polyester-based resin B and a color material which can absorb 0.15 to 10.00 parts by mass of laser light with respect to 100 parts by mass of the polyester-based resin B (“laser light absorbing color material”) And a polyester-based resin B is a resin containing any one of the following (B1), (B2) and (B3).
(B1) Polybutylene terephthalate copolymer resin (B2) Polybutylene terephthalate homopolymer (B2-1) and polybutylene terephthalate copolymer resin, polyethylene terephthalate resin, polycarbonate resin, and aromatic vinyl resin selected from the group consisting of Resin composition containing at least one resin (B2-2) (B3) selected from the group consisting of polybutylene terephthalate copolymer resin (B3-1), polyethylene terephthalate resin, polycarbonate resin and aromatic vinyl resin Resin composition containing at least one resin (B3-2)   The laser weldment according to claim 1, wherein the polybutylene terephthalate homopolymer of the member I has an intrinsic viscosity of 0.5 to 2 dl / g.   The polybutylene terephthalate copolymer resin of member II contains isophthalic acid as a copolymerization component, and the ratio of the isophthalic acid component to all the carboxylic acid components is 1 to 30% by mole as a carboxylic acid group. The laser-welded article according to item 1 or 2.   The laser-welded article according to any one of claims 1 to 3, wherein the laser light transmitting and absorbing color material contains a mixture of azine compounds having an azine skeleton.   The laser welded body according to any one of claims 1 to 4, wherein the laser light absorbing color material contains carbon black.   The member I is a member capable of transmitting and absorbing laser light, and the other member II is a member capable of absorbing laser light, The laser-welded body according to any one of claims 1 to 5, .

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