WO2019088058A1 - Laser welded body production method - Google Patents

Abstract

A laser welded body production method which involves laser welding a transmission-side member for transmitting at least part of a laser beam and an absorption-side member for absorbing the laser beam to one another via a joining surface, the method being characterized in that: the joining surface is shaped so as not to have an axis of symmetry; the transmission-side member comprises a composition which contains a colored material capable of transmitting and absorbing a laser beam in a thermoplastic polyester resin; the absorption-side member comprises a composition which contains a thermoplastic polyester resin and a colored material capable of absorbing without transmitting the laser beam; and the welding is performed between the two members while applying a pressing force of 10 N/mm or less per unit distance.

Description

Method of manufacturing laser welded body

The present invention relates to a method of manufacturing a laser-welded body, and more particularly, relates to a method of manufacturing a laser-welded body, which is made of a polyester resin and has a complex shape welding joint surface with stable high welding strength.

In recent years, with regard to the environment such as weight reduction and recycling for automobile parts and household parts in recent years, resinification of parts that conventionally used metals, miniaturization of resin products, and the like are in progress. Polyester resins are widely used for various equipment parts because they are excellent in mechanical strength, chemical resistance, electrical insulation, etc. and have excellent heat resistance, moldability and recyclability. . In particular, thermoplastic polyester resins such as polybutylene terephthalate resin are excellent in mechanical strength and moldability, and can be made flame-retardant, so they are widely used for electrical and electronic parts that require fire safety. ing.

These equipment parts are provided with spaces inside to accommodate electronic circuits, drive units such as motors and fans, electronic circuits, connectors, etc., and moldings for these are divided into a plurality of resin members. By bonding and manufacturing the molded products, weight reduction and optimization of the shape by hollowing can be achieved as compared with the case of integral molding.
As a method of joining resin members, there is a method of using an adhesive, mechanical joining, hot plate welding, vibration welding, ultrasonic welding, heat welding, etc. Recently, resin members, electronic components to be accommodated, etc. A method of producing a laser-welded body having advantages such as less influence on the performance and good workability has been attracting attention.

Laser welding is performed by overlapping the transmitting side member that transmits the laser beam and the absorption side member that absorbs the laser beam, and applying laser light to the bonding surface from the transmitting side member side for scanning. The absorption side member is melted to weld both members.
However, as compared with polycarbonate resins and polystyrene resins, thermoplastic polyester resins, in particular polybutylene terephthalate resins, have low laser permeability and thus have poor laser welding properties, and welding strength tends to be insufficient.

In addition, since polybutylene terephthalate resin is a crystalline resin, a height difference due to warp deformation is easily generated in a member obtained by molding the same, and a gap is generated at the joint surface between resin members to be joined. In some cases it is more difficult to obtain high weld strength. In recent years, with the increasing complexity of product design, there has been a need to use a laser to weld a complex-shaped molded body with a joining surface that is not annular or the like and that does not have a symmetry axis. There is a problem that the welding is not sufficient in complicated shapes where there is no symmetry axis.

In order to improve the laser weldability of polybutylene terephthalate resin, a method (Patent Document 1) has been proposed in which polybutylene naphthalate (PBN) or polyethylene naphthalate (PEN) is blended. However, this method is not sufficient to improve the welding strength of members having a gap at the joint surface. Moreover, while providing a protrusion in an absorption side member, the method of irradiating a laser beam in the state which pressurized both resin materials with a jig etc., and various protrusion shapes (patent document 2) are proposed. However, although it is an effective method to install ridges, to form various ridges and apply pressure, it is effective to use a combination of a permeable material and an absorbent material, or in the case of complicated shapes without a symmetry axis. And stable welding is difficult. Furthermore, Patent Document 3 proposes a method in which a protrusion is provided on the joint surface of the transmission side member, and the protrusion shape is a polygon and pressure is applied, but in a complicated shape in which the symmetry axis does not exist, It is difficult to obtain stable welding strength only by the combination of the transmitting material and the absorbing material. Extremely pressing to fill the gap also has the problem of distorting the product shape.

Patent No. 3510817 gazette JP 2005-288934 A JP, 2011-5705, A

An object (problem) of the present invention is to provide a method of manufacturing a laser-welded body for laser-welding a member having a complex-shaped welding joint surface with stable high welding strength in view of the above situation.

As a result of repeated studies to solve the above problems, the inventors of the present invention have found that the transmission side member contains heat that can transmit and absorb laser light (hereinafter referred to as "laser light transmission / absorption color material"). A transparent polyester-based resin made of a thermoplastic polyester-based resin and containing a color material (hereinafter referred to as "laser light-absorbing color material") which can be absorbed by the absorption-side member without transmitting laser light; It has been found that the above-mentioned problems can be solved by performing laser welding while applying a pressing force per unit distance of 10 N / mm or less between both members because there is no symmetry axis on the bonding surface of the absorbing side members. I reached.
The present invention relates to the following method for producing a laser-welded article.

[1] A manufacturing method of a laser welded body in which at least a part of a transmitting side member transmitting a laser beam and an absorbing side member absorbing a laser beam are laser-welded via a bonding surface, the bonding surface has a symmetry axis Has a shape that does not exist,
The transmission side member is made of a composition containing a thermoplastic polyester resin and a laser light transmitting and absorbing color material, and the absorption side member is made of a composition containing a thermoplastic polyester resin and a laser light absorbing color material,
A method of manufacturing a laser-welded body, characterized in that welding is performed while applying a pressing force of 10 N / mm or less per unit distance between both members.
[2] The method for producing a laser-welded article according to the above [1], wherein the difference in height of the bonding surface of the absorption side member with the transmission side member under no pressure is 0.01 mm or more.
[3] The method for producing a laser-welded article according to the above [1] or [2], wherein a convex portion is formed on the bonding surface of the absorbing side member.
[4] The method for producing a laser-welded article according to any one of the above [1] to [3], wherein the spot diameter of the laser beam is 1.5 to 3.0 mm.
[5] The absorption side member is any one of the above-mentioned [1] to [4], wherein the outline of the bonding surface in contact with the transmission side member is composed of two or more lines selected from a plurality of curves and straight lines having different curvatures. The manufacturing method of the laser welding body as described in ,.
[6] The laser welding according to any one of the above [1] to [5], wherein the output of the laser, the line to be welded, the scanning speed, and / or the scanning method is varied in accordance with the shape of the bonding surface of the absorbing member How to make the body.
[7] The convex portion provided on the joint surface of the absorbing side member, the reduction amount of the height of the convex portion before and after welding is 0.06 to 0.6 mm, according to any one of [3] to [6] The manufacturing method of the laser welding body as described. [8] The transmission side member has the laser light transmittance of the bonding portion thereof partially different and continuously changing. The production of the laser welded body according to any one of the above [1] to [7] Method.
[9] The laser welding according to any one of the above [1] to [8], wherein the spot diameter of the laser beam is selected according to the shape, width, and height of the convex portion provided on the bonding surface of the absorption side member How to make the body.
[10] The method for producing a laser-welded article according to any one of the above [1] to [9], wherein the laser light transmitting and absorbing color material is nigrosine.
[11] The method for producing a laser-welded article according to any one of the above [1] to [10], wherein the laser light-absorbing color material is carbon black.

According to the method of manufacturing a laser-welded article of the present invention, it is possible to perform laser welding with stable high welding strength, even for a member having a complicated joint surface.

It is a general view which shows an example of the manufacturing method of the laser welding body of this invention. It is a figure which shows the shape of the convex part (convex line) provided in the joint surface of the absorption side member used for the Example. It is a figure which shows the shape of the permeation | transmission side member used for the reference example 1, and the absorption side member.

The method for producing a laser-welded body according to the present invention is a method for producing a laser-welded body, in which at least a part of a transmitting side member transmitting laser light and an absorbing side member absorbing laser light are laser-welded via a bonding surface. The joint surface has a shape without an axis of symmetry,
The transmission side member is made of a composition containing a thermoplastic polyester resin and a laser light transmitting and absorbing color material, and the absorption side member is made of a composition containing a thermoplastic polyester resin and a laser light absorbing color material,
Welding is performed while applying a pressing force per unit distance of 10 N / mm or less between both members.

Hereinafter, the contents of the present invention will be described in detail. The following description may be made based on typical embodiments and examples of the present invention, but the present invention is not construed as being limited to such embodiments and examples.

[Thermoplastic polyester resin (A)]
The transmission side member and the absorption side member used in the method for producing a laser-welded article of the present invention are formed of a molded article of a thermoplastic polyester resin (A).

As the thermoplastic polyester resin (A), (A1) polybutylene terephthalate homopolymer, (A2) polybutylene terephthalate copolymer resin, (A3) homo-PBT mixed resin containing polybutylene terephthalate homopolymer, or (A4) It is preferable that it is either of the copolymerization PBT type | system | group mixed resin containing polybutylene-terephthalate copolymerization resin.

<(A1) Polybutylene Terephthalate Homopolymer>
Polybutylene terephthalate homopolymer (also referred to as "homo PBT") is a polymer having a structure in which terephthalic acid units and 1,4-butanediol units are ester-linked, and is composed of terephthalic acid units and 1,4-butanediol units. Polymer.

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 More preferably, 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.

<(A2) 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 Family 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 other diol units 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.
Further, the ratio of 1,4-butanediol in the diol unit is preferably 70 mol% or more, and more preferably 90 mol% or more.

In addition to the above-mentioned bifunctional monomers, the copolymerized PBT is a trifunctional or tetrafunctional alcohol such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, or trimethylolpropane to introduce a branched structure. Small amounts of polyfunctional monomers and monofunctional compounds such as fatty acids can also be used in combination for molecular weight control.

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 more preferably 5% by mass or more and 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.
Further, in the case of a copolymerized PBT copolymerized with 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.

<(A3) Homo PBT-based mixed resin containing polybutylene terephthalate homopolymer>
Homo PBT-based mixed resin containing polybutylene terephthalate homopolymer (also referred to as "homo PBT-based mixed resin") comprises a polybutylene terephthalate homopolymer (A3-1), a polybutylene terephthalate copolymer resin, a polyethylene terephthalate resin, a polycarbonate resin And a resin composition comprising at least one resin (A3-2) selected from the group consisting of aromatic vinyl resins.

(Polybutylene terephthalate homopolymer (A3-1))
The polybutylene terephthalate homopolymer is the same as the polybutylene terephthalate homopolymer (A1) described above.

(Polybutylene terephthalate copolymer resin (A3-2-1))
The polybutylene terephthalate copolymer resin (A3-2-1) is the same as the polybutylene terephthalate copolymer resin (A2) described above.

(Polyethylene terephthalate resin (A3-2-2))
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 .
Further, 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, preferably 0.4 dl / g or more or 1.2 dl / g or less, and more preferably 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 such a viewpoint, 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 (A3-2-2))
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-dihydroxydiphenyl and the like can be mentioned, with preference given to bisphenol A. 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 PC mentioned above, an aromatic polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane, or 2,2-bis (4-hydroxyphenyl) propane and other aromatic dihydroxy compounds, as mentioned above 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 5,000 to 30,000, more preferably 10,000 or more or 28,000 or less, and still more preferably 14,000 or more or 24,000 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 mass average molecular weight Mw to 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 (A3-2-3))
The aromatic vinyl-based resin is a polymer having an aromatic vinyl compound 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.
As the aromatic vinyl resin, for example, polystyrene (PS), acrylonitrile-styrene (AS), methyl methacrylate-styrene (MS), styrene-maleic acid copolymer and the like are representative.

A rubber component can be copolymerized with the aromatic vinyl resin. Examples of the rubber component 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) etc. 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, α methacrylate such as cyclohexyl methacrylate Α, β-unsaturated carboxylic acid esters, α, β-unsaturated dicarboxylic acid 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.

The aromatic vinyl resin preferably has a mass average molecular weight of 50,000 to 500,000 measured by GPC. 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 resin, the mass average molecular weight measured by GPC is preferably 50000 to 500000, and more preferably 100000 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 resin preferably has a melt flow rate (MFR) of 0.1 to 50 g / 10 min measured at 220 ° C. and 98 N. 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 resin is butadiene rubber-containing polystyrene, it is preferable that the MFR measured at 49 ° C. and 49 N is 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 and copolymerized PBT)
(A3) When the homo-PBT mixed resin contains homo-PBT and copolymerized PBT, the content ratio of copolymerized PBT is 10 to 90 mass% in the total 100 mass% of homo-PBT and copolymerized PBT. Is preferred.
If the said content rate of copolymerized PBT 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 a moldability will improve, it is preferable. From this point of view, the content ratio of the copolymerized PBT is preferably 10 to 90% by mass in the total 100% by mass of the homo PBT and the copolymerized PBT, and more preferably 15% by mass or more and 85% by mass or less It is more preferable that the content is% or more or 80% by mass or less.

(Homo PBT + PET)
(A3) When the homo-PBT mixed resin contains homo-PBT and PET, the content ratio of PET is preferably 5 to 50% by mass in 100% by mass in total of homo-PBT and PET. If the said content rate of PET 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 ratio of PET is preferably 5 to 50% by mass in the total 100% by mass of homo PBT and PET, and more preferably 10% by mass or more or 45% by mass or less, among them 15% by mass or more It is further preferable that the content is at most mass%.

(Homo PBT + PC)
When the (A3) homo-PBT mixed resin contains homo-PBT and PC, the content ratio of PC is preferably 5 to 50% by mass in 100% by mass in total of homo-PBT and PC. If the said content rate of PC is 5 mass% or more, since laser welding performance becomes high, it is preferable, and if the content rate concerned is 50 mass% or less, since moldability will improve, it is preferable. From this point of view, the content of PC is preferably 5 to 50% by mass in the total 100% by mass of homo PBT and PC, and more preferably 10% by mass or more or 45% by mass or less. It is further preferable that the content is at most mass%.

(Homo PBT + aromatic vinyl resin)
(A3) When the homo-PBT mixed resin contains homo-PBT and an aromatic vinyl-based resin, the content of the aromatic vinyl-based resin is 5 out of the total 100% by mass of the homo-PBT and the aromatic vinyl-based resin. It is preferable that the content be about 50% by mass. If the said content rate of aromatic vinyl-type resin 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 ratio of the aromatic vinyl resin is preferably 5 to 50% by mass in the total 100% by mass of the homo PBT and the aromatic vinyl resin, and in particular, 10% by mass or more or 45% by mass or less It is more preferable that it is 15 mass% or more or 40 mass% or less among these.

In the above, the preferred content ratio in the case of combining homo PBT (A3-1) and one of copolymerized PBT, PET, PC, and aromatic vinyl resin (A3-2) is described. However, a plurality of types may be used by appropriately selecting from the above (A3-2), 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. In addition, it is preferable that the total of (A3-2) described above does not exceed 100% by mass in each ratio range.
For example, in the case where an aromatic vinyl resin and PC are used in combination as (A3-2), 50% by mass or more of homo PBT, 5 to 50% by mass of the aromatic vinyl resin, and 5 to 50% by mass of PC It is preferable to make 100 mass%.
Further, also in (A4) described later, when a plurality of types are used from (A4-2), they can be combined in the same way as described above.

<(A4) Copolymerized PBT mixed resin containing polybutylene terephthalate copolymer resin>
A copolymerized PBT-based mixed resin containing a polybutylene terephthalate copolymer resin (hereinafter also referred to as "copolymerized PBT-based mixed resin") comprises a copolymerized PBT (A4-1), PET, PC and an aromatic vinyl-based resin It is preferable that it is a resin composition containing at least one resin (A4-2) selected from the group.

At this time, the copolymerized PBT (A4-1) in the copolymerized PBT-based mixed resin (A4) is the same as the copolymerized PBT in the homo-PBT-based mixed resin (A3).
Further, PET, PC and aromatic vinyl resin in the copolymerized PBT mixed resin (A4) are the same as PET, PC and aromatic vinyl resin in the homo PBT mixed resin (A3), respectively.

(Copolymerized PBT + PET)
When the copolymerized PBT-based mixed resin (A4) contains the copolymerized PBT and PET, the content ratio of PET is preferably 50% by mass or less in 100% by mass in total of the copolymerized PBT and PET. If the said content rate of PET is 50 mass% or less, since it is excellent in a moldability, it is preferable. From this point of view, the content of PET is preferably 50% by mass or less, and more preferably 5% by mass or more or 40% by mass or less, among them 5% by mass or 30% of the total 100% by mass of the copolymerized PBT and PET. It is further preferable that the content is at most mass%.

(Copolymerized PBT + PC)
When the copolymerized PBT-based mixed resin (A4) contains the copolymerized PBT and PC, the content ratio of PC is preferably 50% by mass or less in 100% by mass in total of the copolymerized PBT and PC. If the content ratio of PC (B3-2) is 50% by mass or less, it is preferable because of excellent moldability. From this point of view, the content of PC is preferably 50% by mass or less in the total 100% by mass of the copolymerized PBT and PC, and more preferably 5% by mass or more and 40% by mass or less. It is further preferable that the content is at most mass%.

(Copolymerized PBT + aromatic vinyl resin)
When the copolymerized PBT-based mixed resin (A4) contains the copolymerized PBT and the aromatic vinyl resin, the content ratio of the aromatic vinyl-based resin is 100% by mass in total of the copolymerized PBT and the copolymerized PBT. It is preferable that it is 50 mass% or less. If the said content rate of aromatic vinyl-type resin is 50 mass% or less, since it is excellent in a moldability, it is preferable. From this point of view, the content of the aromatic vinyl resin is preferably 50% by mass or less, and more preferably 5% by mass or more or 45% by mass or less in 100% by mass in total of the copolymerized PBT and the copolymerized PBT. More preferably, it is 5% by mass or more or 40% by mass or less.

[Transmission side member]
The transmission side member that transmits the laser light is a member made of a resin composition containing the thermoplastic polyester resin (A) and the laser light transmitting and absorbing color material, transmits at least a part of the laser light, and a part of the laser Absorbs light.
Examples of the laser light transmitting and absorbing color material include azines such as nigrosine and aniline black, phthalocyanines, naphthalocyanines, porphyrins, quaterylenes, azos, azomethines, anthraquinones, squaric acid derivatives, immonium, quinacridones, etc. , Dioxazine, Diketopyrrolopyrrole, Anthrapyridone, Isoindolinone, Indanthrone, Perinone, Perylene, Indigo, Thioindigo, Quinophthalone, Quinoline, Triphenylmethane, etc. Organic dyes and pigments can be mentioned. 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, as the above-mentioned laser light transmitting and absorbing color material contained in the transmitting side member, in order to enhance the degree of blackness, a dye and pigment (X) mainly absorbing at the laser light wavelength and a dye and pigment transmitting mainly the laser light 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. By containing nigrosine, the transmission side member is also heated and melted by the laser beam, and sufficient welding strength can be achieved even in a complicated shape in which appropriate welding is difficult if only the heat absorption of the absorption side member is melted.

Nigrosine is a mixture of azine compounds having an azine skeleton, which functions as a dye having laser light absorbability, and has moderate absorption in the range of 800 nm to 1200 nm laser light. 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.

The content of the dye and pigment (X) such as nigrosine is preferably 0.001 to 0.6 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). When the content of the dye and pigment (X) is 0.001 parts by mass or more, the dye and pigment (X) are uniformly dispersed, and the laser light is absorbed and the resin is uniformly fused, which is preferable. And, if it is not more than 0.6 parts by mass, it is preferable because the laser light is transmitted, and foaming due to decomposition of the resin hardly occurs.
From such a viewpoint, the content of the dye and pigment (X) is preferably 0.001 to 0.6 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A), and more preferably 0.02 parts by mass or more Alternatively, it is more preferably 0.3 parts by mass or less, and more preferably 0.05 parts by mass or more or 0.1 parts by mass or less.

Examples of the dye (Y) that mainly transmits the 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 exhibiting blue (hereinafter also referred to as "blue dyes") and dyes and pigments exhibiting yellow are disclosed. A combination of a dye (hereinafter also referred to as “yellow dye”) and a dye / pigment exhibiting red (hereinafter also referred to as “red dye”), a dye / pigment (hereinafter referred to as “purple dye”) exhibiting purple, and a combination of yellow dye And combinations of dyes and pigments (hereinafter also referred to as “green dyes”) exhibiting a green color, dyes such as red dyes and blue dyes, and dyes and pigments exhibiting a brown color (hereinafter also referred to as “brown dyes”). it can.

Preferred blue dyes are anthraquinone dyes having a maximum absorption wavelength in the range of 590 to 635 nm. Anthraquinone dyes are usually blue, oil-soluble dyes. By combining this dye as the above laser light transmitting and absorbing color material contained in the transmitting side member, for example, the visibility is higher than that of the green anthraquinone dye, and even when combining a black mixed dye, a red dye in subtractive color mixture, 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 having a maximum absorption wavelength in the range of 590 to 635 nm, it is preferable to select one having a measurement value (decomposition start temperature) of 300 or higher in thermogravimetric analyzer TG / DTA in the presence of air.

Preferred anthraquinone dyes 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 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 having good heat resistance is selected, and a red perinone dye having a maximum absorption wavelength in the range of 460 to 480 nm can be mentioned. Examples of such perinone dyes are 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 dye 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 having good heat resistance is selected, and an anthraquinone dye having a maximum absorption wavelength in the range of 435 to 455 nm is preferable. Anthraquinone dyes having a maximum absorption wavelength in the range of 435 to 455 nm are usually yellow oil-soluble dyes.
Examples of yellow anthraquinone dyes 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 commercially available yellow anthraquinone dyes include "NUBIAN (registered trademark) YELLOW series, OPLAS (registered trademark) YELLOW series" (all trade names, manufactured by Orient Chemical Industries, Ltd.) and the like.

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

[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, an amino group, an alkyl It is an amino group, a nitro group or a halogen atom. ]

Examples of the alkyl group having 1 to 18 carbon atoms in R ¹ to R ⁸ in formula (1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group and an i-butyl group. , 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. 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.

In the formula (2), R ¹ to R ⁸ are as defined in the above 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.

In the formula (3), R ¹ to R ⁸ are as defined in the above 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 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.
In addition, the azomethine nickel complex used as the said laser beam light transmission absorption color material which a permeation | transmission side member contains is not limited to these.

An anthraquinone dye pigment (C1) having a maximum absorption wavelength in the range of 590 to 635 nm when the dye side pigment (Y) mainly transmitting the laser light used as the laser light transmission and absorption color material is contained in the transmission side member; It is preferable to use a perinone dye pigment (C2) having a maximum absorption wavelength in the range of 460 to 480 nm and an anthraquinone dye pigment (C3) having a maximum absorption wavelength in the range of 435 to 455 nm.
A dye / pigment (X) which is a dye / pigment mainly absorbing at a laser light wavelength due to compatibility with a thermoplastic polyester resin (A) and a dye / pigment (Y) constituting a dye / pigment mainly transmitting a laser beam Since the hue changes, in order to obtain a jet-black molded plate suitable as a black hue, it is desirable to adjust the proportions of the respective dyes constituting the dye / pigment (Y). In that case, the content ratio of C1 to C3 is preferably C1: C2: C3 = 24 to 42:24 to 48:22 to 46 by mass ratio (based on a total of 100 parts by mass of C1, C2, C3) . 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 laser light used as the above-mentioned laser light transmitting / absorbing color material contained in the transmission side member is a perinone dye pigment (C2) having a maximum absorption wavelength in the range of 460 to 480 nm and The colorant preferably contains an anthraquinone dye (C1) having an absorption wavelength of 590 to 635 nm in a mass ratio C2 / C1 of 0.4 to 2 of the two. In consideration of the coloring property by the resin composition used in the present invention and suppression of bleed out, it is more preferably 0.4 to 1.5, still more preferably 0.6 to 1.5.
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 anthraquinones (compounds of wavelengths different from C1 and C3 described above), azomethines, etc. 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 transmission and absorption 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. It is more preferable that the content is 0 part by mass or less, and more preferably 0.005 part by mass or more or 3.0 parts by mass or less.

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 Is preferably 0.0005 to 0.6 parts by mass with respect to 100 parts by mass of the polyester resin (A).
When the content of the dye and pigment (X) is at least 0.0005 parts by mass, it is preferable because the absorbing dye and pigment are uniformly dispersed, and the resin absorbs the laser beam 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 such a viewpoint, the content of the dye / pigment (X) is preferably 0.0005 to 0.6 parts by mass, and more preferably 0.001 parts by mass or more, with respect to 100 parts by mass of the polyester resin (A). 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) 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).
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 particularly preferably 0. More preferably, it is at least 05 parts by mass or at most 4 parts by mass, and more preferably at least 0.1 parts by mass or at most 3 parts by mass.
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.

[Absorption side member]
The absorption side member is made of a resin composition containing a thermoplastic polyester resin (A) and a laser light absorbing color material. Examples of the laser light absorbing color material 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 or more of them may be used in combination. be able to. Among them, those containing carbon black are preferable.

As carbon black, for example, at least one of furnace black, thermal black, channel black, lamp black and acetylene black can be used alone or in combination of two or more.
In order to facilitate dispersion of carbon black, it is also preferable to use one which has been masterbatched in advance with the resin component constituting the thermoplastic polyester resin (A) or another resin.

The primary particle diameter of carbon black is preferably 10 nm to 30 nm, and more preferably 15 nm or more and 25 nm or less, from the viewpoint of dispersibility. When the dispersibility is good, welding unevenness at the time of laser welding is reduced.
The carbon black preferably has a nitrogen adsorption specific surface area of 30 to 400 m ² / g as measured according to JIS K 6217 from the viewpoint of jet blackness, more preferably 50 m ² / g or more, and particularly 80 m ² / g or more. 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, more preferably 40 ^~ 170cm 3 / 100g, more 50 ~ 150 cm ³ / 100 g is preferred. 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 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). 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 10 parts by mass or less, decomposition of the resin due to rapid and excessive heat generation can be prevented. ,preferable.
From such a viewpoint, the content of the laser light absorbing color material is preferably 0.15 to 10 parts by mass, more preferably 0.15 to 5 parts by mass with respect to 100 parts by mass of the polyester resin (A). More preferably, it is 0.15 to 1 part by mass.

Moreover, the absorption side member can contain suitably components other than a thermoplastic polyester-type resin (A) and a laser beam absorption color raw material.

Other components include laser light transmitting and absorbing color materials such as nigrosine. The absorbing side member may or may not contain a laser light transmitting and absorbing color material, such as nigrosine. By not containing a laser ray transmitting / absorbing color material, particularly nigrosine, it is possible to prevent heat-resistant discoloration and light-resistant discoloration.
Nigrosine is as described above. The content of nigrosine in the absorbing side member is preferably 0.001 to 0.6 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). If the content of nigrosine is 0.001 parts by mass or more, nigrosine disperses uniformly, and the laser light is absorbed and the resin is uniformly melted, which is preferable. If the content is 0.6 parts by mass or less, the laser light is welded It is preferable because it can transmit as much as possible, and can suppress foaming due to decomposition of the resin caused by excessive absorption of laser light. The nigrosine content is more preferably 0.02 to 0.3 parts by mass, further preferably 0.05 to 0.1 parts by mass.

[Other ingredients]
The permeation side member and the absorption side member can contain various additives other than the above-described components, as desired. 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]
The shape of the member 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 method of molding the member 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 transmission side member needs to transmit laser light over the 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 laser welded joint of the transmission side member is preferably 0.2 mm to 4.0 mm, and more preferably 0.4 mm or more or 3.5 mm or less, among them 0.5 mm or more More preferably, it is not more than 0. 0 mm.

[Relationship between transmitting side member and absorbing side member]
From the viewpoint of bonding strength, in the transmission side member and the absorption side member, the difference between the melting point Tm-A of the transmission side member and the crystallization temperature Tc-A ((Tm-A)-(Tc-A)) is absorbed More preferably, the difference is larger than the difference between the melting point Tm-B of the side member and the crystallization temperature Tc-B ((Tm-B)-(Tc-B)). In particular, ((Tm-A)-(Tc-A))-((Tm-B)-(Tc-B)) is in the range of 0 to 30 ° C., although it is strongly affected by the resin used for the absorbing side member. Among these, the range of 2 to 20 ° C. is more preferable, and the range of 3 to 15 ° C., further preferably 4 to 10 ° C. is particularly preferable.
In order to do so, for example, adjustment of the mixing ratio of the thermoplastic polyester resin (A) used for the absorption side member, selection of various additives and adjustment of the compounding amount, thermoplastic polyester resin used for the transmission side member Selection of the laser ray transmitting / absorbing dye and pigment (A) and adjustment of the compounding amount may be performed. However, it is not limited to these adjustment methods.

Further, from the viewpoint of bonding strength, the thermoplastic polyester in which the melting enthalpy ΔHm-A of the transmitting side member and the melting enthalpy ΔHm-B of the absorbing side member are the melting enthalpy ΔHm-A of the transmitting side member is used for the absorbing side member More preferably, it is higher than the melting enthalpy ΔHm-B of the resin (A). The range of (ΔHm-A)-(ΔHm-B) is preferably in the range of 0 to 20 J / g, more preferably in the range of 0.5 to 10 J / g, and even more preferably in the range of 2 to 9 J / g.
In order to do so, for example, adjustment of the mixing ratio of the thermoplastic polyester resin (A) used for the absorption side member, selection of various additives and adjustment of the compounding amount, thermoplastic polyester resin used for the transmission side member The selection and blending amount of the laser ray transmitting / absorbing dye pigment (A) may be adjusted. However, it is not limited to these adjustment methods.
The melting point Tm, the crystallization temperature Tc, and the melting enthalpy ΔHm are obtained by cutting out a sample from a location at which the distance from the gate of the injection mold of the transmission side member and the absorption side member formed by injection molding is 5 mm or more It is determined by measurement.

[Method of producing laser welded body]
The manufacturing method of the thermoplastic polyester resin (A) used for the permeation | transmission side member and the absorption side member should just produce a resin composition by a normal method, respectively, and should just shape | mold a resin composition by a normal method.
For example, the raw materials constituting the transmission side member or the absorption side member may be mixed, and may be 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.

In addition, a master batch is prepared by melt-kneading a part of the resin constituting the transmission side member or the absorption side member with a part of the other resin, to prepare a masterbatch, and then the remaining resin and other components are added thereto. It may be melt-kneaded.
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 appropriately selected usually from the range of 220 to 300.degree. 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 forming the transmission side member and the absorption side member.
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.

[Laser welding]
Laser welding is performed by surface contact or point contact between the transmitting side member and the absorbing side member formed by injection molding or the like of the above-mentioned thermoplastic polyester resin material, and laser light is irradiated from the transmitting side member side. The bonding interface of the invention is at least partially melted and integrated into one molded article.
The shapes of the transmitting side member and the absorbing side member are not limited as long as the shapes of the respective members can be joined by laser welding, but in the present invention, even if the transmitting side member and the absorbing side member have complicated shapes Since welding is possible, no symmetry axis exists in the shape of the joint surface when the joint surface between the transmission side member and the absorption side member is viewed from the transmission side member. In particular, the shape of the absorption side member is composed of two or more lines selected from the group consisting of a plurality of curved lines and straight lines having different curvatures when the joint surface is viewed from the transmission side member. Is preferred.
The transmission side member may have the same size and shape as the joint portion of the absorption side member, may be larger than the joint portion of the absorption side member, and may have a different shape.

Hereinafter, the manufacturing method of the laser welding body of this invention is demonstrated, also referring drawings.
FIG. 1 is a schematic view showing an example of the method for producing a laser-welded body of the present invention. For example, as shown in FIG. 1, the absorbing side member 1 is a box-shaped member having a polygonal shape of a to f in which the upper surface 3 has a partially cut rectangular shape, and the shape of the transmitting side member 2 is, for example, As shown in FIG. 1, it has a lid-like shape covering the absorbing side member 1, and the lower surface thereof is in surface contact with the joint surface 3 of the absorbing side member 1.

The joint surface 3 of the absorption side member 1 and the transmission side member 2 may be smooth or rough, and may have a convex protrusion or a fitting structure intentionally. In particular, it is preferable to form a protrusion on the bonding surface. The shape in the case of providing the convex portion is not particularly limited, but the vertical cross-sectional shape of the convex portion may be, for example, a chevron, a semicircle, a triangle, a square or a trapezoid, or a shape combining them. Also, the width and height thereof are arbitrary depending on the laser spot diameter and the desired shape of the welded body.

In particular, a convex portion is preferably formed on the absorbing side member. In FIG. 1, although the convex streak 4 in which the convex part was connected linearly is formed so that the perimeter of the periphery of the joint surface 3 of the absorption side member 1 may be circled, two or three convex streaks are formed. It may be provided so as to be parallel to the columns or more, and two or three or more parallel columns may be provided in which the convex portions are continuously provided in the form of dots.

In addition, the height difference of the bonding surface is caused by various factors, for example, it is generated as sink marks and warpage due to, for example, primary shrinkage and secondary shrinkage (annealing, etc.), and these are composites such as molded article shape and molding conditions Caused by a factor. Moreover, the influence may affect the whole molded article, or may affect the details such as the convex portion. This height difference is desirably minimized to obtain a sufficient welding strength, and it is possible to optimize the combination of the resin composition, molding conditions, annealing conditions, etc. In some cases, more or less difference in height may be acceptable, as it also relates to the tolerance of and the manufacturing cost. In the method of the present invention, it is possible to achieve sufficient welding strength even if there is a height difference of 0.01 mm or more.
The height difference of the bonding surface is preferably 0.01 to 0.5 mm, more preferably 0.02 to 0.4 mm, and still more preferably 0.05 to 0.3 mm or less.

The height difference of the joint surface is shown as the difference between the highest position and the lowest position with respect to the reference surface in the entire welding planned line. The height difference of the bonding surface changes continuously.
In addition, sink marks and warpage may occur on either or both of the transmission side member and the absorption side member, and may occur on both of them. In particular, the height difference in the case of the member side where the convex portion is not provided is joined from the reference surface The distance to the surface. Furthermore, when a recess or a protrusion is formed on both sides, it is expressed as a gap when the two members are superposed under no pressure, and these can be used as dedicated inspection tools, or simply as a gap gauge, Measure using a dial gauge, height gauge and dial gauge together.
Measurement is made into the distance from a reference surface to a joint surface or a convex part top surface by making three points of the permeation | transmission side member and / or the absorption side member into a reference plane.

The transmittance of the transmission side member is not particularly limited as long as at least a part of the laser light can be transmitted, but the transmittance at a wavelength of 940 nm of 1.5 mm is preferably 5 to 99%, more preferably Is preferably 15 to 80%, more preferably 20 to 70%.
The transmittance does not differ greatly as long as it is a test piece shape such as JIS standard, but in a practical product shape, depending on the gate position of the molded product and the shape of the molded product, high and low transmittances can be obtained. The transmittance is often not completely uniform, and the laser light transmittance of the junction of the transmission side member is partially different and often changes continuously. In the case of different transmittances, welding strength is likely to vary when welding is performed with the same output and the same scanning speed, but in the method of the present invention, the laser light transmittance is partially different and molding changes continuously. It is possible to obtain good welding strength even with products.

The type of laser beam to be irradiated for the laser deposition is not particularly limited, but can be selected from solid laser, fiber laser, semiconductor laser, gas laser, liquid laser and the like. 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. In particular, laser light having a wavelength of 940 n, 980 nm, 1070 nm is preferable. The oscillation mode may be CW or pulse. The irradiation method is also not particularly limited, and a laser head is moved by a robot, a galvano scan method in which a laser beam is reflected by a mirror and scanned, a large number of laser heads are equipped, and a method of irradiating simultaneously on a welding surface It can be selected appropriately.

The laser spot diameter is preferably 0.1 mm or more and 30 mm or less, more preferably 0.2 mm or more and 10 mm or less, still more preferably 0.3 mm or more and 5 mm or less, and particularly preferably 1.5 to 3.0 mm. Below this range, welding tends to be difficult, and beyond this range, it becomes difficult to control the welding width. Moreover, it is preferable to select the spot diameter of a laser beam according to the shape, width, and height of a convex part.
The laser light may be focused on the bonding surface or may be defocused, and is appropriately selected according to the desired weld.

The welding conditions are not particularly limited, and differ depending on the specifications of the apparatus, and various selections are made depending on the combination of various conditions such as laser type, laser diameter, laser output, scanning speed, members to be welded, and member shapes. For example, the laser output is preferably 1 to 1000 W, more preferably 10 to 500 W, and still more preferably 15 to 200 W. At higher powers the cost of the laser welding equipment becomes too high, below which it tends to be difficult to obtain sufficient welding strength.
The laser scanning speed is preferably 0.1 to 20000 mm / s, more preferably 1 to 10000 mm / s, and still more preferably 10 to 1000 mm / s.
Further, as the laser scanning method, it is possible to make the laser output, the welding scheduled line, the scanning speed and / or the scanning method variable in accordance with the shape of the bonding surface, welding efficiency, welding strength, welding appearance, device load More preferable in point.

When performing laser welding, first, the transmission side member 2 and the absorption side member 1 are superimposed on the convex portion 4 of the joint surface 3, and the transmission side member 2 and the absorption side member 1 are maintained in a superimposed state. In order to maintain the overlapped state, a transparent plate such as a glass plate, a quartz plate, or an acrylic plate may be disposed on the transmission side member 2, 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 and for obtaining a good appearance.

Then, the laser beam X is scanned and irradiated from above the transmission side member 2 onto the welding scheduled line 5 corresponding to the convex portion 4 provided on the peripheral edge of the absorption side member 1. At this time, most or most of the laser beam X passes through the transmission side member 2. And the laser beam X is absorbed centering on the convex part 4 of the absorption side member 1, and the surface vicinity of the convex part 4 heat | fever-generates and fuse | melts. Further, depending on the resin composition of the transmission side member 2, a part of the laser beam X is absorbed and heated to contribute to welding. Also, at the time of joining by laser welding of at least both members, both members are 10 N / mm or less, preferably 9 N / mm or less, more preferably 5 N / mm or less, particularly preferably 3 N / mm or less. Apply pushing force per unit distance. If pressure is applied more than this, residual stress tends to remain in the molded product, and the difference in height due to warpage tends to be large, so that smoke can not be generated or sufficient welding strength can not be obtained. By doing this, the bonding surface of the absorption side member 1 and the transmission side member melt together, and after the irradiation of the laser beam X is stopped, the melted portions of the transmission side member 2 and the absorption side member 1 are cooled. By solidification, both members are welded and integrated with high strength.
Moreover, it is preferable that the pushing force per unit distance sets it as 0.4 N / mm or more. If it is less than this, adhesion of the joint surface can not be maintained, and welding becomes difficult.
The pressing force per unit distance at the time of joining of both members by laser welding is obtained by dividing the actual pressing force (N) by the length (mm) of the circumference of the welding scheduled line as described in the example. Be

The scanning of the laser beam X may be performed in one round toward the convex portion 4 of the bonding surface 3 of the absorbing side member 1, and two or three or more rounds of scanning may be performed. The selection of the scanning position is important because the scanning of the laser beam X deviates from the welding scheduled line (the convex portion 4 in FIG. 1), causing smoke and difficulty in welding.

When a convex portion is provided on the bonding surface of the absorbing side member, the reduction amount of the height of the convex portion is preferably 0.06 to 0.6 mm before and after the laser welding. The reduction amount (change amount) of the height of the convex portion can be measured by digitizing the displacement due to the convex portion melting at the time of welding using a displacement gauge.

In laser welding, the total heat amount (J) to be described below greatly contributes to the degree of welding, so even if the various conditions are different, excellent welding can be obtained by making the total heat amount (J) the same index. You can easily make it possible.
The total heat amount is calculated by the following equation.
Heat input (J / mm) = Output (W) / Scanning speed (mm / s)
Total heat (J) = 1 round scanning distance (mm) × number of turns (times) × heat input (J / mm)

According to the method of manufacturing a laser weldment of the present invention, it is possible to obtain a weldment having high bonding strength. The bonding strength of the welded body according to the present invention is preferably 300 N or more, more preferably 500 N or more, particularly preferably 750 N or more, 900 N or more, and further preferably 1000 N or more, 1200 N or more.

In the case of laser welding, depending on the conditions, the resin may be decomposed or smoke may be generated due to various factors. This smoke is a gaseous thing which consists of resin decomposition products, and it may cool and adhere to a welding object, and the appearance may be impaired remarkably. Furthermore, when an electronic component etc. are incorporated in the inside of a welding body, the bad influence to an electronic component may be given and it is unpreferable. Therefore, it is preferable not to smoke even if the welding strength is sufficient.
In addition, the output and scanning speed of the laser welding device have limits from the mechanical point of view, and if welding is performed under conditions near the upper limit, a welded body with stable bonding strength can not be obtained, which may result in defective products. Not only there is a possibility that the device itself may be broken, which is not preferable. Therefore, it is also important to consider these in the determination of weldability.

The shape, size, thickness, etc. of the welded body integrated by laser welding are arbitrary, and as the application of the welded body, electric parts for transportation equipment such as automobiles, electric electronic parts, parts for industrial machines, others It is particularly suitable for consumer parts and the like. In addition, since the welding strength is high and the pressure resistance is high as a result, it is necessary to have airtightness such as a container for incorporating electric / electronic components such as electronic boards, circuits, sensors, solenoids, motors, transformers and batteries inside. It is also preferable to use for various applications.

EXAMPLES Hereinafter, the present invention will be more specifically described with reference to Examples, but the present invention is not construed as being limited to the following Examples.

[Production of Absorbing Side Members A to C]
Each component described in the following Table 2 is blended in the amount (all by mass parts) described in absorption side composition AC of Table 2, and this is knead | mixed at 250 degreeC using the vent type twin screw extruder of 30 mm. The strands were extruded to obtain pellets of absorbing side compositions A to C.

The obtained pellets of the absorption side compositions A to C are dried at 120 ° C. for 7 hours, and then the injection molding machine (“J55” manufactured by Japan Steel Works, Ltd.) is used at a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C. The box-shaped absorption side members A to C as shown in the absorption side member 1 of FIG. 1 were injection molded.
As for the dimensions of the absorbing side members A to C, in FIG. 1, the height h is 20 mm, and the thickness (width) w is 3 mm. Then, on the joint surface 3 having a width w of 3 mm, the ridges 4 having a width of 0.75 mm at the base and a height of 0.7 mm and a cross section of a substantially regular triangle are paralleled in two rows (indicated as double) It is set as a single) so as to go around ab-c-d-e-f-a point on the width center of the joint surface 3. Sectional drawing of the joint surface vicinity which shows the shape of the convex streak 4 was shown to Fig.2 (a), (b). In the case of two rows of ridges 4 shown in FIG. 2 (a), the ridges 4 in the case of one row of ridges 4 shown in FIG. 2 (b) with reference to the center of the width of the two rows of ridges With reference to the center, the distance between each point is a-b: 80 mm, b-c: 50 mm, c-d: 45 mm, d-e: 30 mm, e-f: 35 mm, f- Between a: 20 mm.
The height difference of the top surface of the convex portion on the entire circumference of the ridge 4 of the resulting absorbing side members A to C was measured. Each part at points a to f was measured, and the average height difference of the top face of the convex part of the absorbing members A to C was 0.18 to 0.22 mm as shown in Table 4 below.

[Method of measuring melting point Tm, crystallization temperature Tc, melting enthalpy ΔHm]
A portion to be welded (distance from the gate: 35 mm) of the molded molded absorption side member is cut, and a differential scanning calorimetry (DSC) machine ("Pyris Diamond" manufactured by PerkinElmer Co., Ltd.) is used 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 falling rate of 20 ° C./min. Melting point Tm, melting enthalpy ΔHm, crystallization temperature Tc Was measured.

[Production of Permeable Side Members D to H]
In the production of the transmission side member, dyes (Y-1) to (Y-3) were used in which the components shown in Table 3 below were blended in the proportions shown in Table 3.

Each component described in Table 2 and Table 3 is blended in the amount (all parts by mass) described in the transmission side compositions D to H in Table 2, and this is blended using a 30 mm vent type twin screw extruder 250 The mixture was kneaded at ° C. and extruded into strands to obtain pellets of the permeable material compositions D to H.

The obtained pellets of the above permeable material compositions D to H are dried at 120 ° C. for 7 hours and then injected at a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C. by an injection molding machine (“J55” manufactured by Japan Steel Works, Ltd.) It was molded to manufacture transmission side members D to H having a thickness of 1 mm in the shape shown in FIG. 1 corresponding to the joint surface 3 of the absorption side members A to C.

The transmittance (laser wavelength 940 nm) at points a ′ to f ′ of the planned welding line 5 of the transmission side member 2 corresponding to the ab-c-d-e-fa point of the absorption-side member 1 is as follows As it was.
In the case of the permeable material composition D, a ': 28.1%, b': 30.2%, C ': 27.3%, d': 22.4%, e ': 21.4%, f': 25.3%,
In the case of the permeable material composition E, a ′: 30.5%, b ′: 27.9%, C ′: 29.9%, d ′: 28.6%, e ′: 26.8%, f ′: 28.4%
In the case of the permeable material composition F, a ′: 30.5%, b ′: 27.9%, C ′: 29.9%, d ′: 28.6%, e ′: 26.8%, f ′: 28.4%
In the case of the permeable material composition G, a ′: 30.5%, b ′: 27.9%, C ′: 29.9%, d ′: 28.6%, e ′: 26.8%, f ′: 28.4%
In the case of the permeable material composition H, a ′: 60.9%, b ′: 63.3%, C ′: 57.6%, d ′: 57.6%, e ′: 41.9%, f ′: 57.6%

[Method of measuring melting point Tm, crystallization temperature Tc, melting enthalpy ΔHm]
A portion to be welded (distance from the gate: 35 mm) of the formed molded body of the transmission side member is cut, and using a differential scanning calorimetry (DSC) machine ("Pyris Diamond" manufactured by PerkinElmer Co., Ltd.), 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 falling rate of 20 ° C./min. Melting point Tm, melting enthalpy ΔHm, crystallization temperature Tc Was measured.

[Laser welding evaluation]
(Examples 1 to 10, Comparative Examples 1 to 5, Reference Example 1)
As described in Tables 4 and 5, any one of the transmission side members A to C is on the transmission side, and one of the absorption side members D to H is on the absorption side, and the two are superimposed on each other. The laser beam X is irradiated from the periphery of the transmission side member 2 toward the ridges 4 of the absorption side member 1 while applying the pressing force (unit: N / mm) per unit distance described in 5. The laser welding was performed so as to scan around along the To measure the pressing force (N / mm) per unit distance, set a coin-type load cell (manufactured by IMADA CO., LTD., LM-20 kN) on a pressure stage attached with a pressure cylinder (SMC air cylinder (φ 100 mm)) And the actual pressure was measured. It was set as the value which remove | divided the obtained applied pressure (N) by length (mm) of 1 round of the welding scheduled line. In Reference Example 1, the laser beam X is formed in the two rows shown in FIG. 2 (a) formed on the bonding surface 3 of the absorption side member 1 having a cylindrical shape (diameter 48 mm, height 20 mm) shown in FIG. Convex stripes 4 (each convex stripe has a width of 0.75 mm at the base, a height of 0.7 mm, and a cross section of substantially regular triangle).

For laser welding, a laser device manufactured by Fine Device (laser wavelength: 940 nm, laser spot diameter φ2.1 mm, maximum output 140 W, maximum scanning speed 200 mm / s) was used. Various welding conditions are shown in Tables 4 to 5.

The laser welding strength of the welded body was measured. To measure the joint strength of the weldment, use a tensile tester (“1t Tensilon” manufactured by ORIENTEC Co., Ltd.) and attach the push rod attached to the test jig inserted before welding inside the weldment, It evaluated by weighting by 5 mm / min from the absorption side member side.
The amount of reduction (the amount of change) of the height of the ridges 4 was measured by a displacement gauge attached to the pressure stage.

The determination of the weldability was performed based on the following criteria in consideration of the load of the laser welding apparatus and the like.
A: There is no smoke, welding strength of welding portion is larger than 900 N, welding speed is less than 85% of the maximum scanning speed of 200 mm / s of the laser device.
B: No smoke. Bonding strength 900 N or less, or welding speed 85% or more of the maximum speed C: With smoke.
The above results are shown in Tables 4 and 5 below.

In Examples 1 to 10, although smoke was generated at the time of welding in Comparative Examples 1 to 5 and welding was defective, no smoke at the time of welding was confirmed, and sufficient bonding strength was obtained. Example 6 was judged to be useful because it has a lower strength but is at a practical level and does not emit smoke. In addition, in the reference example 1, although it is a pressing force per unit distance, since it is a cylindrical symmetrical shape, smoke generation at the time of welding is not confirmed, and sufficient bonding strength was obtained.

The method for producing a laser-welded body according to the present invention can perform laser welding with stable high welding strength even if it is a polyester member in which a gap is generated at the joint surface. It can be suitably used for the production of equipment parts, parts for industrial machines, and other parts for consumer use. In addition, since the welding strength is high and the pressure resistance is high as a result, it is necessary to have airtightness such as a container for incorporating electric / electronic components such as electronic boards, circuits, sensors, solenoids, motors, transformers and batteries inside. It is also preferable to use for various applications.

1: Absorbing side 2: Transmission side 3: Bonding surface 4: Convex part (convex line)
5: Welding schedule line X: Laser light

Claims (11)

1. A manufacturing method of a laser welded body, in which at least a part of a transmitting side member transmitting a laser beam and an absorbing side member absorbing a laser beam are laser welded through a bonding surface, the bonding surface has no symmetry axis Have a shape,
   The transmission side member is made of a composition containing a color material (referred to as “laser light transmission and absorption color material”) capable of transmitting and absorbing laser light to a thermoplastic polyester resin, and the absorption side member is a thermoplastic polyester resin And a color material (referred to as “laser light absorbing color material”) that can absorb laser light without transmitting it, and
   A method of manufacturing a laser-welded body, characterized in that welding is performed while applying a pressing force of 10 N / mm or less per unit distance between both members.
2. The method for producing a laser-welded article according to claim 1, wherein a height difference between a bonding surface of the absorbing side member and the transmitting side member under no pressure application is 0.01 mm or more.
3. The method according to claim 1 or 2, wherein a convex portion is formed on the bonding surface of the absorbing side member.
4. The method for producing a laser-welded article according to any one of claims 1 to 3, wherein the spot diameter of the laser beam is 1.5 to 3.0 mm.
5. The laser according to any one of claims 1 to 4, wherein the absorption side member is constituted of two or more lines selected from a plurality of curved lines and straight lines having different curvatures and the outline of the bonding surface in contact with the transmission side member. Method of manufacturing a welded body.
6. The method of manufacturing a laser weldment according to any one of claims 1 to 5, wherein the output of the laser, the planned welding line, the scanning speed, and / or the scanning method is varied according to the shape of the bonding surface of the absorbing side member. .
7. The laser-welded article according to any one of claims 3 to 6, wherein a reduction of the height of the projections before and after welding is 0.06 to 0.6 mm of the projections provided on the joint surface of the absorbing side member. Manufacturing method.
8. The method for producing a laser-welded article according to any one of claims 1 to 7, wherein in the transmission side member, the laser light transmittance of the joint portion is partially different and continuously changes.
9. The method according to any one of claims 1 to 8, wherein the spot diameter of the laser beam is selected according to the shape, width, and height of the convex portion provided on the bonding surface of the absorbing side member. .
10. The method according to any one of claims 1 to 9, wherein the laser light transmitting and absorbing color material is nigrosine.
11. The method according to any one of claims 1 to 10, wherein the laser light absorbing color material is carbon black.

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