JP6725157B2 - Laser welded body and method for manufacturing the same - Google Patents

Description

The present invention relates to a laser-welded body in which resin members having different absorbances are laser-welded and integrated, and a manufacturing method thereof.

In recent years, lightweight thermoplastic resin products have often been used in place of metals for structural parts in the fields of vehicles such as automobiles and railways, and electronic/electrical devices. Examples of the thermoplastic resin used for these structural parts include, for example, polyester resin, polyamide resin, and polycarbonate resin, and among these, polyester resin and polyamide resin typified by polybutylene terephthalate resin and polyethylene terephthalate resin are Because of its excellent mechanical properties, electrical characteristics, heat resistance, dimensional stability, and other physical and chemical characteristics, it is widely used in vehicle parts, electric/electronic equipment parts, precision equipment parts, etc.

Among its various uses, in particular, polybutylene terephthalate resin is used in products that seal electrical circuits such as automobile electrical components (control units, etc.), various sensor components, connector components, etc., and polyamide resin is used in products such as intake manifolds. It has been developed into products with various hollow parts. In a product that seals these electric circuits or a product that has a hollow portion, it may be necessary to join a plurality of members to seal the inside. Therefore, various welding/sealing technologies, such as bonding with an adhesive, and bonding technology using welding such as solvent bonding, vibration welding, ultrasonic welding, hot plate welding, injection welding, and laser welding are adopted. ..

Joining with an adhesive contaminates the surroundings due to the organic solvent contained in the adhesive, in addition to the time loss that it takes a long time to cure the adhesive. Also, joining by ultrasonic welding or hot plate welding complicates the welding process because post-treatment is required due to damage to the product due to vibration and heat and generation of abrasion powder and burrs. In addition, joining by injection welding is expensive because it may require a special mold or molding machine, and is not suitable for welding using a material having low fluidity.

In laser welding, a laser light transmitting resin member is layered on a laser light absorbing resin member, and the laser light emitted from the laser light transmitting resin member side passes through this and reaches the laser light absorbing resin member for absorption. This causes heat to be generated, and both resin members are heat-melted and welded to be joined.

The features of laser welding are that the resin member can be welded only by locally irradiating laser light to the place to be joined, and because it is a local heat generation, the heat effect on the peripheral part other than the welded part Is very small, no vibration occurs, it is possible to weld resin parts with minute parts or three-dimensional and complicated structures, high reproducibility, high airtightness can be maintained, bonding The strength is high, the boundary between the welded portions is inconspicuous, and dust is not generated.

According to the laser welding, the resin members can be surely welded and joined together. Further, the joining strength equal to or higher than that of joining by fastening parts (bolts, screws, clips, etc.) and joining by a method such as an adhesive, vibration welding, and ultrasonic welding can be obtained. Moreover, laser welding does not generate vibration and can minimize the influence of heat, so that it is possible to realize labor saving, improvement in productivity, and reduction in manufacturing cost. Therefore, laser welding is suitable for joining functional parts and electronic parts that should avoid the effects of vibration and heat, for example, in the automobile industry, electric/electronic industry, etc., and can also join resin parts having complicated shapes. ..

As a technique related to laser welding, in Patent Document 1, a laser light transmitting resin member and a laser light absorbing resin member containing a carbon black that absorbs laser light are superposed on each other. A method of joining by welding both resin members by irradiating a laser beam from the resin member side is described. According to this method, when the laser light is irradiated from the laser light absorbing resin member side, the laser light is absorbed in the surface layer of the resin member and the resin members cannot be welded to each other. Laser light irradiation from the side is essential. In this method, for example, a laser light absorbing resin member is arranged as an outer cylinder, and laser light irradiation can be performed from the outer cylinder side of a resin component in which a laser light transmitting resin member is arranged as an inner cylinder to be inserted therein. Can not. Therefore, a desired resin member cannot be arranged in the resin component, and the degree of freedom in designing the resin component is narrowed.

Patent Document 2 discloses a laser in which the thermoplastic resin members A and B and a heat dissipation material C having an infrared ray transmitting portion are brought into contact with each other in a positional relationship of C/A/B, and infrared rays are emitted from the heat dissipation material C side. Welding methods are described. According to this method, the thermoplastic resin members A and B may be molded with the same kind of thermoplastic resin. However, this laser welding method requires a special heat-dissipating material C in order to adjust the heat generation during laser welding. This complicates the laser welding process.

In Patent Document 3, a resin member that transmits laser light and a resin member that absorbs laser light are joined together by joining flange portions formed in advance as welding margins, and a joining flange portion of the resin member that transmits laser light is disclosed. There is described a laser welding method in which both resin members are provisionally welded by irradiating a laser beam from the side and then the main welding is performed again by irradiating the joint flange portion with the laser beam to integrate both resin members. According to this laser welding method, since the number of laser irradiation steps increases the number of steps, the resin member joining step by welding is prolonged and the manufacturing cost of the resin component is kept high.

Japanese Patent Publication No. 62-049850 International Publication 2003/039843 JP 2004-351730 A

The present invention has been made to solve the above-mentioned problems, and among the resin members that are superposed, it is possible to irradiate the laser beam from the resin member side having the laser beam absorption property, without going through complicated steps. Provided is a laser-welded body which can be easily joined by integrating a plurality of resin members prepared in a single laser-welding step, and is excellent in joint strength between resin members, and which does not impair resin characteristics, and a manufacturing method thereof. The purpose is to

The inventors of the present invention have a laminated structure in which a laser light weakly absorbing resin member having a specific absorbance of absorbing and transmitting laser light and a laser transmitting resin member having an absorbance of transmitting laser light are stacked. It has been found that, by irradiating a resin member with weak laser light absorption with laser light, a wide and deep melting phenomenon is caused at the interface between the resin member with weak laser light absorption and the resin member transmitting laser light. .. Thereby, the inventors can obtain a laser welded body in which resin members are bonded to each other much more strongly than in the conventional laser welding in which a laser light transmitting resin member and a laser light absorbing resin member are welded. The present invention has been completed.

The laser welded body of the present invention made to achieve the above object is a laser light irradiation side resin member containing a thermoplastic resin and nigrosine and having an absorbance a _{1 of} 0.1 to 0.5. The first resin member and the second resin member containing the same or different thermoplastic resin as the thermoplastic resin and having an absorbance a _{2 of} 0.01 to 0.098 are formed by overlapping. in at least some of the contact sites are laser welded, the absorbance ratio _a 1 / _{a 2} and the absorbance _{a 1} and the absorbance _{a 2} is from 1.3 to 45 der shall.

In the laser welded body, for example, the first resin member has a content of the nigrosine of 0.01 to 0.2 mass %, and the volume resistivity of the nigrosine is 0.5×10 ^{9 to} 5.0×. An example is 10 ¹¹ Ω·cm .

The laser-welded body may have a fusion-bonded portion that is spread to the first resin member side with respect to the second resin member, at least at a part of the laser-welded contact portion .

In the laser welded body, the nigrosine may be nigrosine sulfate, and the sulfate ion concentration of the nigrosine sulfate may be 0.3 to 5 mass % .

The laser welded body may have a melt flow rate of the first resin member of 11 to 30 g/10 minutes .

Examples of the laser welded material include those having the absorbance a ₂ of 0.01 to 0.09 .

The laser welded body is at least a part of an abutting portion formed by contacting ends of the first resin member and/or ends of the second resin member adjacent to each other, and It is preferable that the ends are laser-welded .

Laser welding can be, for example, the first resin member and / or said second resin member, shall have been divided and the like to a plurality of the resin piece in contact said at contact sites.

In the laser welded body, the second resin member is divided into two resin member pieces, and the absorbance a _2-1 and the absorbance a _2-2 thereof are 0.05 to 0.09, and the absorbance a is ₁ to the absorbance ratio of the absorbance _{a 2-1 a} 1 _{/ a 2-1,} or absorbance ratio _a 1 _{/ a 2-2} with the absorbance _{a 1} and the absorbance _{a 2-2,} 1.3-45 May be

Laser welding body, said first resin member and the second resin member, it is preferable that the have a butt portion is formed by being butted at their ends.

In the laser welded body, the second resin member may contain a colorant containing anthraquinone and/or nigrosine .

Examples of the laser-welded body include those in which the thermoplastic resin is at least one selected from polyamide resin, polycarbonate resin, polyphenylene sulfide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, and polypropylene resin.

Method for manufacturing a laser welded product of the present invention includes: a first resin member to have a absorbance a ₁ of 0.1 to 0.5 and containing a thermoplastic resin and nigrosine, thermoplastic of the thermoplastic resin and the same or different A second resin member containing a resin and having an absorbance a _{2 of} 0.01 to 0.098 is superposed to form a contact portion at their interface and/or their ends are butted to form a butted portion. Then, by irradiating the contact portion and/or the abutting portion with laser light from the first resin member side to melt the contact portion and/or the abutting portion, a first resin member and a second resin member are formed. Is to be welded. In particular, when nigrosine is nigrosine sulfate, high-speed scanning laser welding can be dealt with, and thus a manufacturing method having high work efficiency can be provided.

The method for manufacturing a laser welded body may be one in which the laser light is irradiated to cause the first resin member to melt, and then the melt grows toward the contact portion.

In the laser welded body of the present invention, the laser light weakly absorbing resin member, which is the first resin member, transmits the laser light while absorbing the laser light, so that the laser light incident from the laser light weakly absorbing resin member absorbs the laser light weakly. Of the conductive resin member and the laser light transmitting resin member, which is the second resin member overlapping the resin member, reach the contact portion, and the contact portion is melted. As a result, it is surely and firmly welded. As described above, the laser-welded product of the present invention is obtained by irradiating a laser beam from the weakly laser-absorbing resin member side to weld the resin members together. Further, at the abutting portion where the ends of the weakly laser-absorbing resin member and the transparent laser-transmitting resin member are butted against each other, the heat of the weakly-absorbing laser light resin member generated by the incidence of the laser light is As a result of conduction to the member and melting of the abutting portion, the laser welded body is welded similarly to the welding at the contact portion.

In addition, the laser-welded material shows higher fluidity when the weakly laser-absorbing resin member contains the sulfate of nigrosine as the laser-light absorber, so that the weakly-absorbing laser light which is melted by the incidence of laser light is shown. Since the resin member quickly flows toward the laser-transmissive resin member at the contact portion and/or the abutting portion to melt and weld the resin member at those portions, the resin member can be attached to the contact portion and/or the abutting portion. Even if voids are formed due to surface roughness or sink marks, the voids are closed and high welding strength is exhibited. It is one of the features of the present invention that it can be applied to welding members having shapes that are difficult to be welded by ordinary heat conduction.

According to the method for producing a laser-welded product of the present invention, a laser light weakly absorbing resin member is overlapped with a laser light-transmitting resin member to form a contact portion, or both end portions of both resin members are butted against each other to form a contact portion. After forming the laser beam, adjust the irradiation angle of the laser light to the laser light irradiation surface of the laser light weakly absorbing resin member, and quickly irradiate these parts with the laser by a simple method. Can be welded. In particular, when welding both resin members that have been overlapped with each other at the contact portion, laser light irradiation can be performed from the laser light weakly absorbing resin member side, so that, for example, laser light is applied to a structure formed of conventional resin members. A laser welded body can be obtained after the fact by superimposing a weak light absorbing resin member and irradiating with a laser.

It is a perspective view which shows an example in the middle of manufacturing the laser welded body to which this invention is applied, and the AA arrow schematic partial cross section figure. It is a schematic cross section which shows the middle of manufacturing another laser welded body to which this invention is applied. It is a schematic cross section which shows the middle of manufacturing another laser welded body to which this invention is applied. It is a perspective view which shows an example in the middle of manufacturing the laser welded body to which this invention is applied. It is a perspective view showing the middle of manufacturing another laser welding object to which the present invention is applied. It is a perspective view showing the middle of manufacturing another laser welding object to which the present invention is applied. It is a schematic cross section which shows the middle of manufacturing another laser welded body to which this invention is applied. It is a cross-sectional enlarged photograph of the fusion|melting site|part of the laser welding body of Examples 1-3 and 1-4 to which this invention is applied. It is a perspective view showing the middle of manufacturing the laser welding thing of Examples 5-1 and 5-2 to which the present invention is applied, and an expanded partial sectional view of it.

Hereinafter, modes for carrying out the present invention will be described in detail, but the scope of the present invention is not limited to these modes.

FIG. 1(a) is a perspective view showing the process of manufacturing the laser welded body of the present invention, and FIG. 1(b) is a partial schematic cross-sectional view taken along the line AA of the laser welded body. The laser welded body 10 is formed by integrating a plurality of resin members by joining them by laser welding. The laser welded body 10 is formed by superimposing the laser light weakly absorbing resin member 1 which is the first resin member and the laser light transmitting resin member 2 which is the second resin member, and the overlapping surfaces of the resin members 1 and 2 are overlapped with each other. It is welded at the contact portion C which is a part of. Both resin members 1 and 2 are in the shape of a flat rectangular plate having a uniform thickness. Both the resin members 1 and 2 contain a thermoplastic resin, and the weak laser light absorbing resin member 1 contains nigrosine as a laser light absorbing agent. The laser light absorbing agent acts as a laser light transmitting/absorbing agent by having a laser light absorbing property of absorbing a part of laser light and a laser light transmitting property of transmitting another part thereof. To do.

The weakly laser light absorbing resin member 1 is a member to be irradiated with laser light, which is arranged on the irradiation side of the laser light L. The laser light L is irradiated substantially perpendicular to the irradiation surface of the laser light transmitting resin member 1. The laser light L scans linearly in the X direction at a speed of 0.5 to 10.0 mm/sec, for example. As a result, the laser welded body 10 has both resin members 1 and 2 which are welded and integrated by solidifying after forming a large molten pool at the contact portion C.

The weakly laser beam absorbing resin member 1 has a laser beam transmitting/absorbing property of absorbing a part of the wavelength of the incident laser beam L and transmitting a part of another wavelength. The absorbance a ₁ of the weakly laser light absorbing resin member 1 is preferably 0.1 to 0.5 with respect to laser light having a wavelength range of 940 nm emitted from a semiconductor laser, for example. It is more preferably 11 to 0.47. Since the absorbance a ₁ is within this range, the laser light weakly absorbing resin member 1 has heat generation characteristics required for welding with the laser light transmitting resin member 2 and excessive heat generation due to energy concentration of the incident laser light L. It is compatible with deterrence. As a result, the laser welded body 10 can be obtained by the irradiation operation of the laser light L from the weakly laser light absorbing resin member 1 side that absorbs the laser light.

When the absorbance a ₁ exceeds the above upper limit value, the laser light weakly absorbing resin member 1 excessively absorbs the laser light L, so that energy concentration occurs at the incident position of the laser light L. Therefore, the scope of selection of laser welding conditions such as laser output and scanning speed is narrowed, and it becomes difficult to control laser irradiation. Therefore, the laser light weakly absorbing resin member 1 is likely to be scratched, scorched, or void, and the laser welded body 10 is likely to cause poor appearance. Furthermore, the weakly laser-absorbing resin member 1 does not reach the contact portion C in the molten pool, which is the molten portion melted on the incident surface side of the laser light L, and a laser welded body having high welding strength cannot be obtained. .. On the other hand, if the absorbance a ₁ is less than the above lower limit value, the amount of heat generated is insufficient even if the laser light weakly absorbing resin member 1 is irradiated with the laser light L, and the weakly laser light absorbing resin member 1 is transparent to laser light. It does not generate heat or melt enough for welding with the resin member 2. Therefore, the laser welded body 10 cannot be obtained.

The melt flow rate (based on JIS K7210:2014) of the laser light weakly absorbing resin member 1 is preferably 10 to 50 g/10 minutes, and more preferably 11 to 30 g/10 minutes. In addition, since the weakly laser-absorbing resin member 1 contains nigrosine, it has a lower crystallization temperature than that of the resin member formed of the thermoplastic resin contained in the weakly-laser light absorbing resin member 1. It has and has improved liquidity. In particular, when the laser light weakly absorbing resin member 1 contains nigrosine sulfate, the crystallization temperature is lower than that of the resin member containing nigrosine hydrochloride, and the effect of improving fluidity is remarkable. Therefore, the weakly laser-absorbing resin member 1 that has been thermally melted by the incidence of the laser light L has a high fluidity at the time of melting, so that the contact portion C is caused by the surface roughness and sink marks of the two resin members 1 and 2. Even if the voids are formed, the heat-melted laser light weakly absorbing resin member 1 flows into the voids and surely closes them, so that the resin members 1 and 2 are firmly welded. The melt flow rate of such a laser light weakly absorbing resin member 1 is preferably 11 to 30 g/10 minutes, more preferably 12 to 20 g/10 minutes, and 13 to 18 g/10 minutes. More preferably.

The laser light transmitting resin member 2 is formed of a thermoplastic resin which is the same as or different from the raw material resin of the laser light weakly absorbing resin member 1. The absorbance a ₂ of the laser light transmitting resin member 2 is 0.01 to 0.098, which is less than 0.1 at the maximum with respect to the laser light having a wavelength range of 940 nm emitted from a semiconductor laser. Is more preferable, 0.01 to 0.09 is more preferable, 0.05 to 0.09 is still more preferable, and 0.07 to 0.09 is still more preferable. Further, the laser light transmittance is preferably 20% or more. The absorbance a _{2 in} such a range can be obtained by the absorbance originally possessed by the thermoplastic resin contained as the raw material of the laser light transmitting resin member 2. On the other hand, when the absorbance of the thermoplastic resin is less than the above lower limit value, the raw material composition of the laser light transmitting resin member 2 contains a very small amount of a laser light absorbing agent such as nigrosine, for example, 0.001 to 0.08. By including it in a content of mass%, the absorbance a ₂ in the above range can be imparted to the laser light transmitting resin member 2. Since the contained nigrosine absorbs the laser light, the laser light transmitting resin member 2 generates heat at a temperature lower than the heat generated by the weak laser light absorbing resin member 1, and a residual heat effect occurs. This makes it possible to perform laser welding with a small temperature difference between the two resin members 1 and 2. The absorbance a ₂ is particularly preferably 0.07 to 0.098, and more preferably 0.07 to 0.09.

Further, the absorbance ratio _a 1 / _{a 2} between the absorbance _{a 1} and the absorbance _{a 2} is preferably 1.3 to 45, more preferably from 1.5 to 40, is 1.7 to 20 More preferably.

If both resin members 1 and 2 have the same color tone or similar color tone, the laser welded body 10 having a rich design can be obtained because the interface between them and the welding trace are not noticeable. The color tone is preferably a dark color, and particularly preferably a black color tone. For example, it is more preferable to add a colorant containing anthraquinone, specifically a colorant containing an anthraquinone blue dye, a red dye and a yellow dye, to a thermoplastic resin which is a raw material of the laser light transmitting resin member 2.

Such a laser welded body 10 is manufactured as follows. The manufacturing process has the following processes A to D, for example.

Step A: Weakly laser-absorbing resin composition for molding the weakly laser-absorbing resin member 1 containing a thermoplastic resin and a laser light absorbing agent, and optionally a colorant or an additive. Prepare things. The content of the laser light absorber is adjusted based on the absorbance originally possessed by the thermoplastic resin so that the absorbance a ₁ falls within the above range of 0.1 to 0.5. Next, using a molding machine, for example, a rectangular plate-shaped weak laser light absorbing resin member 1 is molded.

Step B: A laser light transmitting resin composition containing a thermoplastic resin which is the same as or different from the thermoplastic resin contained in the weak laser light absorbing resin composition is prepared. When the thermoplastic resin has a remarkably low absorbance, a laser light absorber and/or a coloring agent is added to the laser light transmissive resin composition as necessary, and the absorbance a ₂ is set to 0.1 above. You may adjust so that it may be less than the range, specifically 0.01-0.098, and still more in the range of 0.01-0.09. In this way, the laser light transmissive resin composition for molding the laser light transmissive resin member 2 which generates heat to the extent that it can be welded at the contact portion C upon incidence of the laser light L can be prepared. Next, using a molding machine, for example, a rectangular plate-shaped laser light transmitting resin member 2 is molded.

Step C: The contact portion C is formed by superposing the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 on each other. At this time, both resin members 1 and 2 may be sandwiched by a jig to be pressurized and fixed. Further, a member having an antireflection function, such as a glass plate or an antireflection film, on the surface of the weakly laser light absorbing resin member 1 on the side where the laser light L is incident, or blocking or attenuating the laser light in a desired range. A transparent member such as a glass plate may be arranged.

Step D: The laser light L adjusted to a predetermined condition is applied from the weakly laser light absorbing resin member 1 side to the contact portion C while scanning in the X direction. A part of the laser light L passes through the weakly laser light absorbing resin member 1. Another part is absorbed by the laser light weakly absorbing resin member 1 and heats the contact portion C. The laser light weakly absorbing resin member 1 generates heat at a portion where the laser light L is absorbed, above the melting point of the thermoplastic resin contained therein. As a result, the thermoplastic resin is melted in a liquid state, and a molten pool is formed in a part of the laser light weakly absorbing resin member 1 as if the liquid were accumulated.

Further, the heat of the molten pool is radiated and conducted to the interface between the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2. On the other hand, the laser light transmissive resin member 2 has the absorbance a ₂ , so that it does not entirely transmit a part of the laser light L transmitted through the weak laser light absorbent resin member 1 and absorbs it slightly. Due to the heat conduction of the molten pool and the slight absorption of the laser light L, the laser light transmissive resin member 2 generates heat at the contact portion C and melts. As a result, the molten pool grows so as to spread from the laser light weakly absorbing resin member 1 toward the laser light transmitting resin member 2 at the contact portion C.

At this time, due to the fact that the absorbance a _{1 of} the laser light weakly absorbing resin member 1 is larger than the absorbance a _{2 of the} laser light transmitting resinous member 2, melting formed on the laser light weakly absorbing resin member 1 side. The pool has a larger volume than that on the laser light transmitting resin member 2 side. In particular, when both resin members 1 and 2 are placed on the work table so that the contact portion C is positioned substantially horizontally, the molten pool generated by the laser light weakly absorbing resin member 1 is permeable to the laser light by gravity. It is easy to grow toward the resin member 2. In this case, the molten pool can be grown in a wider range of the contact site C. The molten pool is cooled, and the thermoplastic resin contained in both resin members 1 and 2 is solidified. As a result, at the contact portion C, a fusion-bonded portion having a substantially elliptical cross section is formed while spreading toward the laser light weakly absorbing resin member 1 side and extending over the laser light transmitting resin member 2. As a result, the two resin members 1 and 2 are firmly joined at the welded contact portion C, and the laser welded body 10 is completed.

In the process D, the surface on the incident side of the laser light L may be subjected to a cooling treatment of blowing low temperature or room temperature air or an inert gas. In addition, when both resin members 1 and 2 generate gas during laser welding, a gas processing device may be used to process the gas. As a result, it is possible to prevent laser burn (burn) on the surface to be irradiated with laser light.

FIG. 2A is a schematic cross-sectional view showing the process of manufacturing another laser welded body 10. The laser light weakly absorbing resin member 1 arranged on the irradiation side of the laser light L is welded to the laser light transmitting resin member 2 overlapping with it at the contact portion C. On the other hand, the laser light transmissive resin member 2 has laser light transmissive resin member pieces 2a and 2b divided into two. The absorbance a _{2-1 of} the laser light transparent resin member piece 2a and the absorbance a _2-2 of the laser light transparent resin member piece 2b are, for example, for laser light having a wavelength range of 940 nm emitted from a semiconductor laser, The maximum value is less than 0.1, preferably 0.01 to 0.098, more preferably 0.01 to 0.09, still more preferably 0.05 to 0.09, It is even more preferably 0.07 to 0.09. The absorbance a _2-1 and the absorbance a _2-2 may be the same or different from each other as long as they are within this range. Also preferably the absorbance ratio _a 1 _{/ a 2-1} the absorbance _{a 1} and the absorbance _{a 2-1} laser light weakly-absorbing resin member 1 is 1.3 to 45, in 0.07 to 0.09 More preferably. Absorbance ratio between the absorbance _{a 1} and the absorbance _{a 2-2 a} 1 _{/ a 2-2} is the same as the absorbance ratio _a 1 _{/ a 2-1.} The absorbance ratio a ₁ /a _2-1 and the absorbance ratio a ₁ /a _2-2 may be the same or different from each other as long as they are within this range.

The laser-transmissible resin member pieces 2a and 2b are welded to each other at contact portions N which are adjacent to each other and whose end portions are in contact with each other. The laser light L is applied directly above the contact portion N. Thereby, the laser light weakly absorbing resin member 1 and the laser light transmitting resin member pieces 2a and 2b are welded and integrated at the contact portion C and the contact portion N.

FIG. 2B shows a schematic cross-sectional view showing the process of manufacturing another laser welded body 10. The laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 are overlapped with each other to form a contact portion C. The weakly laser-absorptive resin member 1 is divided into two weakly-laser-absorbent resin member pieces 1a and 1b, which are adjacent to each other and have their ends contacting each other. Thereby, the contact portion N is formed. Laser light L is irradiated to the contact portion N from the laser light weakly absorbing resin member 1 side, whereby the laser light weakly absorbing resin member pieces 1a and 1b and the laser light transmitting resin member 2 come into contact with each other. The parts C and the contact parts N are welded and integrated.

FIG. 2C shows a schematic cross-sectional view showing the process of manufacturing another laser welded body 10. The laser light weakly absorbing resin member 1 having a rectangular shape has a first joint portion 1c on one side thereof, and the laser light transmitting resin member 2 having a rectangular shape has a second joint portion 2c on one side thereof. , Respectively. Both joint portions 1c and 2c have a step shape with the same height. Since the step shapes of the joint portions 1c and 2c are opposed to each other and are combined in an alternating manner, the contact portion C where the resin members 1 and 2 are overlapped with each other, and the upper butting portion B where the ends thereof are butted against each other. ₁ and the lower butt portion B ₂ are formed. In the contact portion C, the first joint portion 1c is arranged on the incident side of the laser light L. The laser light L is emitted from the first joint portion 1c side, whereby the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 are welded and integrated at the contact portion C.

Further, by irradiating the laser beam L to the upper butting portion B ₁ and the lower butting portion B ₂ as well, both resin members ₁ and ₂ are welded to the butting portions B ₁ and B ₂ in addition to the contact portion C. May be. Thereby, it is possible to obtain the laser welded body 10 composed of the two resin members 1 and 2 which are welded with higher strength. In this case, the laser light L may be obliquely irradiated toward the upper butting portion B ₁ and the lower butting portion B ₂ so that the laser light weakly absorbing resin member 1 is incident.

FIG. 2D is a schematic cross-sectional view showing the process of manufacturing another laser welded body 10. The laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 are overlapped with each other to form a contact portion C. The laser light weakly absorbing resin member 1 is divided into two to form the laser light weakly absorbing resin member pieces 1a and 1b, and the laser light transmitting resin member 2 is also divided into two to form the laser light transmitting resin member pieces 2a and 2b. Each has it. Thereby, the first contact portion N ₁ where the ends of the laser light weakly absorbing resin member pieces 1a and 1b contact each other, and the second contact portion where the ends of the laser light transmitting resin member pieces 2a and 2b contact each other. Contact portions N ₂ are formed respectively. The first contact portion N ₁ is overlapped with the laser light transmitting resin member piece 2a, and the second contact portion N ₂ is overlapped with the weakly laser light absorbing resin member piece 1b. That is, the first contact portion N ₁ and the second contact portion N ₂ are formed so as not to overlap each other.

On the other hand, the laser light L is along the X direction (see FIG. 1A and the depth direction in FIG. 2D) on the surface of the weakly laser light absorbing resin member 1b, and the Y direction is orthogonal to the X direction. Scanning is also performed (in the left-right direction in FIG. 2D). As a result, both the resin members 1 and 2 are welded in a wide range of the contact portion C, and also welded in both contact portions N ₁ and N ₂ . Further, since the contact portions N ₁ and N ₂ are deviated from each other, the first contact portion N ₁ is on the laser light transmitting resin member piece 2 a and the second contact portion N ₂ is on the weak laser light absorbing resin. The members 1b are respectively supported. As described above, the resin members 1 and 2 have a high contact area C that is welded over a wide area, and the contact areas N ₁ and N _{2 that} are welded while being supported by the resin member pieces 1b and 2a, respectively. It is strongly welded. As a result, this laser welded body 10 is unlikely to cause peeling at the welded portion even when subjected to an external force such as bending or twisting.

Since both resin members 1 and 2 are molded into an arbitrary shape, the laser welded body 10 may have a curved or bent roll shape, a cylindrical shape, a prismatic shape, or a box shape. For example, the laser-transmissible resin member 2 may be formed in a tubular shape having both ends opened as shown in FIG. 3(a), and as shown in FIG. Alternatively, it may have an abutting portion N that is folded or formed in a valley fold and is in contact with its ends while abutting each other. Even if the laser light transmitting resin member 2 has such a shape, by arranging the laser light weakly absorbing resin member 1 on the irradiation side of the laser light L and irradiating it with the laser light L, To obtain a laser welded body 10 in which both resin members 1 and 2 are welded at a contact portion C between the resin members 1 and 2 and/or a contact portion N where the ends of the laser light transmitting resin member 2 are butted against each other. You can

As shown in FIG. 4, a label 4 which is a laser light weakly absorbing resin member is superposed on an existing transparent resin bottle 3 which is a laser light transmitting resin member, and a laser beam L is irradiated from above the label 4. Both may be welded at the contact portion between the curved body of the resin bottle 3 and the label 4. According to this, it is possible to obtain the laser welded body 10 after the fact by using the resin bottle 3 if necessary.

Further, as shown in FIG. 5A, the ends of the cylindrical members 5a and 5b, which are laser light transmitting resin member pieces, are brought into contact with each other to form an annular contact portion, and weak laser light absorption After the contact portion is formed by covering the contact portion with the belt-shaped member 6 which is a resin member, the laser beam L may be irradiated while being scanned along the belt-shaped member 6 as shown in FIG. According to this, the cylindrical members 5a and 5b and the belt-shaped member 6 are welded at the contact portion N and the contact portion C, and the laser welded body 10 obtained by joining the cylindrical members 5a and 5b is obtained.

Further, as shown in FIG. 6A, a lid 8 which is a laser light weakly absorbing resin member is fitted into the opening of the cylindrical container 7 which is a laser light transmitting resin member to open the opening of the cylindrical container 7. After forming the contact portion between the edge 7a and the lid body 8, the laser beam L may be irradiated while scanning from the lid body 8 side along the contact portion C as shown in FIG. According to this, the laser welded body 10 in which the cylindrical container 7 and the lid body 8 are welded at the contact portion C is obtained.

The weakly laser-absorptive resin member 1 and the laser-transmissive resin member 2 are obliquely incident on the laser light irradiation surface of the weakly laser-absorptive resin member 1 toward the abutting portion formed by abutting. The laser welded body 10 may be manufactured by irradiating the laser welded L on the. For example, as shown in FIG. 7, the end faces of the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 are inclined so that they have the same inclination angle, and the inclined end faces are abutted to each other to meet at the butting portion B. May be formed. In this case, the irradiation angle of the laser light L is preferably an angle of irradiation substantially perpendicular to the inclined end surface. As a result, even if the abutting portion B is inclined, a welding portion extending over a wide range of the abutting portion B is formed, and the laser welded body 10 in which the two resin members 1 and 2 are firmly joined is obtained.

As the laser beam L, an infrared ray having a wavelength range of 800 to 1600 nm longer than visible light, preferably a laser beam having an oscillation wavelength of 800 to 1100 nm can be used. For example, solid-state laser (Nd:YAG excitation and/or semiconductor laser excitation), semiconductor laser, tunable diode laser, titanium sapphire laser (Nd:YAG excitation) can be preferably used. Alternatively, a halogen lamp or a xenon lamp that emits infrared rays having a wavelength of 700 nm or more may be used. The irradiation angle of the laser light may be perpendicular or oblique to the surface of the weakly absorptive laser light-absorbing resin member 1, or may be irradiated from one direction or a plurality of directions. The output of the laser light is appropriately adjusted according to the scanning speed and the absorbances a ₁ and a _{2 of the} resin members 1 and ₂ .

When a halogen lamp that emits infrared rays having a wavelength of 700 nm or more is used, for example, the lamp shape may be a band-shaped lamp. Illumination modes include, for example, a scanning type capable of irradiating a laser beam over a wide range by moving a lamp irradiating unit, a masking type in which a member to be welded moves, and a multi-faceted surface for a resin member to be welded. There is a type in which the lamps are simultaneously irradiated. Irradiation can be performed by appropriately adjusting various conditions such as infrared irradiation width, irradiation time, and irradiation energy. Since the halogen lamp has an energy distribution centered on the near infrared region, energy may exist in the short wavelength side of the energy distribution, that is, in the visible region. In such a case, welding marks may be generated on the surface of the incident member. Therefore, for example, a cut filter may be used to block the energy in the visible region.

The thickness of both resin members 1 and 2 is preferably 200 to 5000 μm. When the thickness is less than 200 μm, it is difficult to control the laser light energy, and during laser welding, excess or deficiency of thermal melting may occur, which may cause breakage due to overheating or insufficient bond strength may not be obtained. On the other hand, when the thickness exceeds 5000 μm, since the distance to the portion to be welded is long, the laser light incident on the weak laser light absorbing resin member 1 is attenuated without being transmitted to the inside thereof. Sufficient bonding strength cannot be obtained.

As the laser light absorber contained in both resin members 1 and 2, nigrosine was mentioned, but in addition to these, salts of nigrosine, azine compounds, aniline black, phthalocyanine, naphthalocyanine, porphyrin, cyanine compounds, perylene, quaterrylene, Examples include azo-based metal complexes, near-infrared absorbing anthraquinones, squaric acid, and immonium dyes. The salt of nigrosine is preferably nigrosine sulfate. Only one of these may be used, or a mixture of two or more of them may have an absorption coefficient ε _d (ml/g·cm) of 1000 to 8000, preferably 1000 to 6000. It is preferably 3000 to 6000 (ml/g·cm).

The absorption coefficient (absorption coefficient) ε _d is measured by precisely weighing 0.05 g of the laser light absorbent and dissolving it in a solvent N,N-dimethylformamide (DMF) using a 50 ml volumetric flask, and then measuring 1 ml thereof. Is diluted with DMF using a 50 ml volumetric flask to obtain a measurement sample, and the absorbance is measured using a spectrophotometer (manufactured by Shimadzu Corporation, trade name: UV1600PC).

Coloring of the thermoplastic resin is performed for the purpose of decorative effect, color-coding effect, improvement of light resistance of the molded product, and protection or concealment of the contents. The most important thing in the industry is black coloring. In addition, since the dispersibility in the resin and the compatibility with the resin are good, coloring with an oil-soluble dye is suitable. Of these, nigrosine is suitable because it can be used as both a black colorant and a laser light absorber and can obtain higher bonding strength.

As nigrosine, C.I. I. Solvent Black 5 and C.I. I. A black azine-based condensation mixture as described in the Color Index as Solvent Black 7 is mentioned. Such nigrosine can be synthesized by, for example, oxidizing and dehydrating and condensing aniline, aniline hydrochloride, and nitrobenzene in the presence of iron chloride at a reaction temperature of 160 to 180°C. From the viewpoint of improving the fluidity of the thermoplastic resin, C.I. I. Solvent Black 5 is more preferable.

The volume resistivity of nigrosine is preferably 0.5×10 ^{9 to} 5.0×10 ¹¹ Ω·cm, and more preferably 3.0×10 ^{9 to} 1.0×10 ¹¹ Ω·cm. preferable. Nigrosine that has undergone the purification step of removing impurities of the inorganic salt does not deteriorate the physical properties of the resin composition that is the raw material of both resin members 1 and 2, and thus can be preferably used. In addition, since the material containing nigrosine exhibiting a high volume resistivity can be suitably used for parts requiring high insulation such as parts of electric/electronic devices and parts of precision devices, it can be used in the industrial world. It can be widely applied. The volume resistivity of nigrosine is calculated as follows. A sample of a certain amount of nigrosine is weighed and solidified by applying a load of 200 kgf, and the volume of this sample is determined. Then, the sample is measured with a digital ultra-high resistance/micro ammeter (manufactured by ADC Co., Ltd., trade name: 8340A).

Nigrosine is preferably a sulfate salt. Since nigrosine sulfate has a function as a fluidity improver, a surface gloss improver, and a crystallization temperature lowering agent, it improves the fluidity of the resin composition during laser welding.

According to the reaction system for producing nigrosine using iron chloride as a catalyst, the reaction is carried out in the presence of iron chloride or excess hydrochloric acid, so that nigrosine hydrochloride is produced. In order to obtain nigrosine sulfate from nigrosine hydrochloride, there is no particular limitation as long as it is a treatment in which all or a substantial part of chloride ions constituting the salt in nigrosine are replaced with sulfate ions, and a known reaction method is used. obtain. In addition, nigrosine sulfate is C.I. I. An oil-soluble black dye belonging to Solvent black 5, and C.I. I. It is not a water-soluble black dye belonging to Acid Black 2.

Specific examples of the method for producing nigrosine sulfate include a method in which nigrosine is dispersed in dilute sulfuric acid and appropriately heated (for example, 50 to 90° C.). In addition, for example, the condensation reaction liquid obtained by producing nigrosine is dispersed in dilute sulfuric acid and appropriately heated (for example, 50 to 90° C.). Further, for example, nigrosine sulfate can also be produced by adding nigrosine to concentrated sulfuric acid while controlling the reaction solution temperature to a low temperature so that sulfonation does not occur, and adding crystals to a large amount of ice water to precipitate crystals. ..

In the nigrosine sulfate, when the sulfate ion concentration is 0.3 to 5% by mass, preferably 0.5 to 3.5% by mass, the effect of lowering the crystal temperature of the thermoplastic resin becomes large, so that it can be easily carried out. Laser welding can be performed stably.

As such nigrosine, NUBIAN BLACK series manufactured by Orient Chemical Industry Co., Ltd. is commercially available.

The content of the laser light absorber such as nigrosine that adjusts the absorbance a ₁ is 0.001 to 0.5 mass% in the weak laser light absorbing resin member 1, and preferably 0.001 to 0.4. It is% by mass. For example, when a polyamide resin is used as the thermoplastic resin for the weak laser light absorbing resin member 1, the content of the laser light absorbing agent is 0.01 to 0.2 mass% in the weak laser light absorbing resin member 1. Is preferable, and 0.01 to 0.15 mass% is more preferable. When the content is less than 0.01% by mass, the absorbance a ₁ is less than the above lower limit value. Therefore, since the heat generation amount of the laser light weakly absorbing resin member 1 which has absorbed a part of the energy of the laser light is too small, they do not heat up sufficiently, and the contact portion C, the butt portion B, and the contact portion N. Insufficient welding will result in insufficient joint strength between the two resin members 1 and 2. If the content exceeds 0.2 mass %, the absorbance a ₁ will exceed the above upper limit. Therefore, the laser light transmittance is excessively decreased, and only the resin member on the laser light incident side, such as the weakly laser light absorbing resin member 1, causes excessive energy absorption to generate heat and melt. , 2 cannot be welded uniformly, and high joint strength cannot be obtained. Further, when the resin member arranged on the laser light incident side absorbs the energy of the laser light excessively, the resin characteristics such as the physical and chemical characteristics of the thermoplastic resin as the raw material thereof are likely to be lost.

On the other hand, as the absorbance a ₂ , the original absorbance of the thermoplastic resin contained in the laser light transmitting resin member 2 can be used as it is. In this case, the laser light transmissive resin member 2 may not contain a laser light absorber or a colorant. When the absorbance of this thermoplastic resin is less than the lower limit of the above-mentioned absorbance a ₂ , a small amount of a laser light absorber can be added to the thermoplastic resin to keep the absorbance a ₂ within the above range.

The thermoplastic resin contained in both resin members 1 and 2 is not particularly limited as long as it can contain a laser light absorber.

Specific examples of the thermoplastic resin include polyphenylene sulfide resin (PPS), polyamide resin (nylon (registered trademark), PA), polyolefin resin such as polyethylene resin and polypropylene resin, polystyrene resin, polymethylpentene resin, Methacrylic resin, acrylic polyamide resin, ethylene vinyl alcohol (EVOH) resin, polycarbonate resin, polyester resin such as polyethylene terephthalate (PET) resin and polybutylene terephthalate (PBT) resin, polyacetal resin, polyvinyl chloride resin, polyvinylidene chloride resin , Polyphenylene oxide resin, polyarylate resin, polyallyl sulfone resin, fluororesin, and liquid crystal polymer.

The thermoplastic resin may be a copolymer resin in which plural kinds of monomers forming the thermoplastic resin are combined. For example, AS (acrylonitrile-styrene) copolymer resin, ABS (acrylonitrile-butadiene-styrene) copolymer resin, AES (acrylonitrile-EPDM-styrene) copolymer resin, PA-PBT copolymer, PET-PBT copolymer Polymer resin, PC-PBT copolymer resin, and PC-PA copolymer resin are mentioned. Further, thermoplastic elastomers such as polystyrene-based thermoplastic elastomers, polyolefin-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, and polyester-based thermoplastic elastomers; synthetic waxes and natural waxes containing these resins as main components are also included. The molecular weight of these thermoplastic resins is not particularly limited. Moreover, you may use these thermoplastic resins individually or in mixture of 2 or more types.

This thermoplastic resin is preferably a polyamide resin, a polycarbonate resin, a polypropylene resin, a polybutylene terephthalate resin, or a polyphenylene sulfide resin. Among them, the polyamide resin and the polycarbonate resin are more preferable from the viewpoint of exhibiting good compatibility with the laser light absorber such as nigrosine.

The polyamide resin in the present invention is a polyamide polymer having an acid amide group (-CONH-) in its molecule and capable of being heated and melted. Preferred is a polyamide resin containing at least one selected from a salt composed of an aliphatic diamine and an aromatic dicarboxylic acid and a salt composed of an aromatic diamine and an aliphatic dicarboxylic acid as a constituent unit (a). The proportion of the structural unit (a) in all structural units of the polyamide resin is preferably 30 mol% or more, more preferably 40 mol% or more. More specifically, various polyamide resins such as polycondensates of lactams, polycondensates of diamines and dicarboxylic acids, polycondensates of ω-aminocarboxylic acids, or copolymerized polyamide resins or blends thereof are available. Can be mentioned. Examples of the lactam which is a raw material for polycondensation of the polyamide resin include ω-laurolactam, enanthlactam, capryllactam, lauryllactam, α-pyrrolidone, α-piperidone, and ω-laurolactam.

Examples of the diamine include tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, octamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2-methylpentamethylenediamine, (2,2,4- or 2,4,4). -) Aliphatic diamines such as trimethylhexamethylenediamine, nonamethylenediamine, 5-methylnonanemethylenediamine; 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3- Diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-diaminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2, Alicyclic diamines such as 2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, bis(aminomethyl)tricyclodecane, bis(aminopropyl)piperazine, and aminoethylpiperazine; metaxylylenediamine (MXDA), paraxylylenediamine, paraphenylenediamine, bis(4-aminophenyl)ether, aromatic diamines such as bis(aminomethyl)naphthalene, and the like.

Examples of the dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, glutaric acid, pimelic acid, undecanedioic acid, dodecadioic acid, hexadecadioic acid, hexadecenedioic acid, eicosandioic acid, dicarboxylic acid. Aliphatic dicarboxylic acids such as glycolic acid and 2,2,4-trimethyladipic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalate Examples thereof include acids, 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, and aromatic dicarboxylic acids such as xylylenedicarboxylic acid.

As the ω-aminocarboxylic acid, for example, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, paraaminomethylbenzoic acid, 2-chloro-paraaminomethylbenzoic acid, 2-methyl-paraaminomethylbenzoic acid, etc. Are listed.

As the polyamide resin, polyamide 6, polyamide 66, polyamide 46, polyamide 11, polyamide 12, polyamide 69, polyamide 610, polyamide 612, polyamide 96, amorphous polyamide, high melting point polyamide, polyamide RIM, polyamide 4, polyamide 6I, Examples thereof include polyamide 56, polyamide 6T, polyamide 9T, polyamide MXD6, polyamide MP6, polyamide MP10, and copolymers of two or more kinds thereof. Specific examples of the copolymer include polyamide 6/66 copolymer, polyamide 6/66/610 copolymer, polyamide 6/66/11/12 copolymer, and crystalline polyamide/noncrystalline polyamide copolymer. Polymers may be mentioned. Further, the polyamide resin may be a mixed polymer of a polyamide resin and another synthetic resin. Examples of such mixed polymers include polyamide/polyester mixed polymers, polyamide/polyphenylene oxide mixed polymers, polyamide/polycarbonate mixed polymers, polyamide/polyolefin mixed polymers, polyamide/styrene/acrylonitrile mixed polymers, polyamide/ Acrylic ester mixed polymers and polyamide/silicone mixed polymers are mentioned. You may use these polyamide resins individually or in mixture of 2 or more types.

The polyphenylene sulfide (PPS) resin is a polymer mainly containing a repeating unit composed of a thiophenylene group represented by (-φ-S-) [φ is a substituted or unsubstituted phenylene group]. The PPS resin is obtained by polymerizing a monomer synthesized by reacting paradichlorobenzene and alkali sulfide at high temperature and high pressure. There are two types of PPS resin, a straight-chain type in which a desired degree of polymerization is obtained only by a polymerization step using a polymerization aid, and a cross-linking type in which a low-molecular polymer is thermally cross-linked in the presence of oxygen. It is roughly classified into. In particular, the linear PPS resin is preferable because it has excellent laser light transmittance. The melt viscosity of the PPS resin is not particularly limited as long as it can be melt-kneaded, but is usually 5 to 2000 Pa.s. The range of s is preferable, and the range of 100 to 600 Pa·s is more preferable.

Further, the PPS resin may be a polymer alloy. For example, PPS/polyolefin alloy, PPS/polyamide alloy, PPS/polyester alloy, PPS/polycarbonate alloy, PPS/polyphenylene ether alloy, PPS/liquid crystal polymer alloy, PPS/polyimide alloy, and PPS/polysulfone. An example is a system alloy. Since the PPS resin has chemical resistance/heat resistance and high strength, it is suitable for applications such as electronic parts and automobile parts.

Examples of the polyester resin include a polyethylene terephthalate resin obtained by a polycondensation reaction of terephthalic acid and ethylene glycol, and a polybutylene terephthalate resin obtained by a polycondensation reaction of terephthalic acid and butylene glycol. Examples of the other polyester resin include 15 mol% or less (for example, 0.5 to 15 mol%), preferably 5 mol% or less (for example, 0.5 to 5 mol%), and/or ethylene glycol in the terephthalic acid component. And in a glycol component such as butylene glycol, 15 mol% or less (for example, 0.5 to 15 mol%), preferably 5 mol% or less (for example, 0.5 to 5 mol%), such as a terephthalic acid component or glycol. Examples thereof include a copolymer in which a part of the components is substituted with a substituent such as an alkyl group having 1 to 4 carbon atoms. Moreover, you may use a polyester resin individually or in mixture of 2 or more types.

As the dicarboxylic acid compound constituting the polyester resin, specifically, an aromatic dicarboxylic acid or its ester-forming derivative is preferably used. As aromatic dicarboxylic acids, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-2,2'-dicarboxylic acid, biphenyl -3,3'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, diphenylether-4,4'-dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, Diphenyl isopropylidene-4,4'-dicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, anthracene-2,5-dicarboxylic acid, anthracene-2,6-dicarboxylic acid, p- Examples thereof include terphenylene-4,4'-dicarboxylic acid and pyridine-2,5-dicarboxylic acid, and terephthalic acid can be preferably used. You may use these aromatic dicarboxylic acid in mixture of 2 or more types. As well known, these can be used in the polycondensation reaction as an ester-forming derivative such as dimethyl ester in addition to the free acid. If the amount is small, an aliphatic dicarboxylic acid such as adipic acid, azelaic acid, dodecanedioic acid, and sebacic acid together with these aromatic dicarboxylic acids, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, etc. One or more kinds of acids and alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid can be mixed and used.

Aliphatic diols such as ethylene glycol, propylene glycol, butanediol, hexylene glycol, neopentyl glycol, 2-methylpropane-1,3-diol, diethylene glycol, and triethylene glycol as the dihydroxy compound constituting the polyester resin. , Cyclohexane-1,4-dimethanol, and other alicyclic diols, and mixtures thereof. If the amount is small, one or more long-chain diols having a molecular weight of 400 to 6000, that is, polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol and the like may be copolymerized. Also, aromatic diols such as hydroquinone, resorcin, naphthalene diol, dihydroxydiphenyl ether, and 2,2-bis(4-hydroxyphenyl)propane may be used. In addition to the above-mentioned bifunctional monomers, trimellitic acid for introducing a branched structure, trimesic acid, pyromellitic acid, pentaerythritol, and trifunctional monomers such as trimethylolpropane, and for adjusting the molecular weight, fatty acids. A small amount of a monofunctional compound such as can be used in combination.

As the polyester resin, a resin mainly containing polycondensation of a dicarboxylic acid and a diol, that is, a resin containing 50% by mass, preferably 70% by mass or more of the polycondensate of the whole resin is used. Aromatic carboxylic acids are preferred as the dicarboxylic acid and aliphatic diols are preferred as the diol. More preferable is polyalkylene terephthalate in which 95 mol% or more of the acid component is terephthalic acid and 95% by mass or more of the alcohol component is an aliphatic diol. Examples thereof include polybutylene terephthalate and polyethylene terephthalate. It is preferable that these are close to homopolyester, that is, 95% by mass or more of the total resin is a terephthalic acid component and a 1,4-butanediol or ethylene glycol component. The main component of the polyester resin is preferably polybutylene terephthalate. The polybutylene terephthalate may be a copolymer of isophthalic acid, dimer acid, and polyalkylene glycol such as polytetramethylene glycol (PTMG).

Examples of the polyolefin resin include homopolymers of α-olefins such as ethylene, propylene, butene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1, and copolymers thereof, and these. And other copolymerizable unsaturated monomers (the copolymer may include a block copolymer, a random copolymer, and a graft copolymer). More specific examples include polyethylene resins such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer; propylene. Polypropylene resins such as homopolymers, propylene-ethylene block copolymers or random copolymers, and propylene-ethylene-butene-1 copolymers; polybutene-1 and poly-4-methylpentene-1. .. These polyolefin resins may be used alone or in combination of two or more. Among these, polyethylene resin and/or polypropylene resin are preferable. More preferably, it is a polypropylene resin. The molecular weight of this polypropylene resin is not particularly limited, and a wide range of molecular weights can be used.

As the polyolefin-based resin, a resin containing a foaming agent such as acid-modified polyolefin modified with an unsaturated carboxylic acid or a derivative thereof or expanded polypropylene may be used. Further, ethylene-α-olefin copolymer rubber, ethylene-α-olefin-non-conjugated diene compound copolymer (for example EPDM), ethylene-aromatic monovinyl compound-conjugated diene compound copolymer rubber, and these The rubber of the hydrogenated product may be contained in the polyolefin resin.

Polycarbonate resin is a thermoplastic resin having a carbonic acid ester bond in the main chain and is an engineering plastic having excellent mechanical properties, heat resistance, cold resistance, electrical properties, and transparency. The polycarbonate resin currently industrially mass-produced is an aromatic polycarbonate obtained from bisphenol A. The phosgene method and the transesterification method are mentioned as a manufacturing method of this. The chemical structural formula of a polycarbonate resin has a bulky benzene nucleus and a flexible carbonate in the main chain of a linear molecule in which a large number of aromatic hydrocarbon carbonates are linked. The former imparts high heat distortion temperature and excellent physical and mechanical properties, and the latter contributes to moldability and flexibility, but is easily hydrolyzed by alkali.

The laser light weakly absorbing resin member 1 contains a laser light absorbing agent such as nigrosine which is a black colorant, and therefore exhibits a gray to black color tone depending on the content thereof. However, since the content of the laser light absorber is determined so as to show the absorbance a _{1 of} 0.1 to 0.5, the color density of the laser light weakly absorbing resin member 1 is not sufficient. There may be a light color. In such a case, in order to impart a desired color density to the weak laser light absorbing resin member 1, a colorant may be added to the weak laser light absorbing resin composition for molding the same. Further, a colorant can be added to the laser light transmitting resin composition for molding the laser light transmitting resin member 2. Thereby, for example, the same color can be given to both resin members 1 and 2, and the interface between them and the welding trace can be made inconspicuous.

The colorant is selected according to the hue and color density of the thermoplastic resin contained in this resin composition. For example, when imparting a dark black color to both resin members 1 and 2, a combination of a blue colorant, a red colorant and a yellow colorant, a combination of a purple colorant and a yellow colorant, a green colorant and a red colorant are combined. A plurality of colorants can be combined to prepare a black colorant, such as a combination with an agent.

Such a colorant is preferably a combination of a plurality of types of dyes which absorbs in the visible region, is highly compatible with a thermoplastic resin, and has a low scattering property for laser light. Further, the colorant is resistant to discoloration even when exposed to high temperatures during molding of both resin members 1 and 2 and melting by irradiation of laser light, and has excellent heat resistance. More preferably, it does not have absorptivity.

Specific examples of such colorants include azomethine-based, anthraquinone-based, quinacridone-based, dioxazine-based, diketopyrrolopyrrole-based, anthrapyridone-based, isoindolinone-based, indanthrone-based, perinone-based, perylene-based, indigo-based. Examples thereof include thioindigo-based, quinophthalone-based, quinoline-based, and triphenylmethane-based organic dyes and pigments. A colorant containing at least an anthraquinone dye that is transparent to laser light used for laser welding is preferable.

Such anthraquinone dye is preferably an anthraquinone oil-soluble dye, and specific examples thereof include C.I. I. Solvent Blue 11, 12, 13, 14, 26, 35, 36, 44, 45, 48, 49, 58, 59, 63, 68, 69, 70, 78, 79, 83, 87, 90, 94, 97, 98, 101, 102, 104, 105, 122, 129, and 132; C.I. I. Disperse Blue 14, 35, 102, and 197; C.I. I. Solvent Green 3, 19, 20, 23, 24, 25, 26, 28, 33, and 65; C.I. I. Available in the Solvent Violet 13, 14, 15, 26, 30, 31, 33, 34, 36, 37, 38, 40, 41, 42, 45, 47, 48, 51, 59, and 60 color indexes. Examples include dyes.

Examples of the anthraquinone dye include those having a maximum absorption wavelength in the range of 590 to 635 nm. Such anthraquinone dye often exhibits a blue color, and has higher visibility than, for example, anthraquinone green dye. When a black mixed dye is combined, a dark black colorant having a high tinting strength can be obtained by subtractive color mixing by combining a red dye or a yellow dye with an anthraquinone blue dye.

The anthraquinone dye preferably has a 940 nm laser light transmittance of 60 to 95%. Examples of such anthraquinone dyes that are commercially available include "NUBIAN (registered trademark) BLUE series" and "OPLAS (registered trademark) BLUE series" (both are trade names, manufactured by Orient Chemical Industry Co., Ltd.). ..

The electrical conductivity of the anthraquinone dye is preferably 50 to 500 μS/cm. According to this, since the insulating properties of both resin members 1 and 2 can be improved, the laser welded body 10 is preferably used for resin parts requiring high insulating properties such as electric/electronic equipment parts and precision equipment parts. be able to.

This electric conductivity is measured as follows. Disperse 5 g of a sample anthraquinone dye in 500 mL of ion-exchanged water, and record the weight. This is boiled to extract ionic components and then filtered. Ion-exchanged water is added until the weight of the filtrate becomes the same as the weight previously measured, and the electric conductivity of this solution is measured with an electric conductivity meter (Toa DKK Co., Ltd., product name: AOL-10).

Examples of the combination of dyes include a combination of anthraquinone blue dye with other blue dye, red dye, and yellow dye, and a combination of anthraquinone blue dye with green dye, red dye, and yellow dye. Examples of this red dye or yellow dye include azo dyes, quinacridone dyes, dioxazine dyes, quinophthalone dyes, perylene dyes, perinone dyes, isoindolinone dyes, azomethine dyes, triphenylmethane dyes, and red or yellow anthraquinone dyes. These may be used alone or in combination of two or more. Examples of dyes that impart good color developability to both resin compositions of a laser light weakly absorbing resin composition and a laser light transmitting resin composition include perinone dyes and red or yellow anthraquinone dyes.

Preferably, a combination of the above-mentioned anthraquinone blue dye and red dye having a maximum absorption wavelength in the range of 590 to 635 nm is used. Suitable examples include the above-mentioned perinone dyes, which have good heat resistance and often show a red color. Examples of commercially available products of such a red dye include "NUBIAN (registered trademark) RED series" and "OPLAS (registered trademark) RED series" (both are trade names, manufactured by Orient Chemical Industry Co., Ltd.).

Specific examples of the perinone dye include C.I. I. Solvent Orange 60; C.I. I. Solvent Red 135, 162, 178, and 179.

Examples of the anthraquinone red dye (including anthrapyridone dye) include C.I. I. Solvent Red 52, 111, 149, 150, 151, 168, 191, 207, and 227; C.I. I. Disperse Red 60 may be mentioned. Such perinone dyes and anthraquinone red dyes are commercially available with the above color index.

Anthraquinone yellow dye is suitable as a dye to be used in combination with such anthraquinone red dye. In the colorant, the range of (i) mass of anthraquinone yellow dye/(ii) mass ratio of blue, green, and/or purple anthraquinone dye (i)/(ii) is 0.15 to 1.0. It is preferable. Examples of commercially available anthraquinone yellow dyes include "NUBIAN (registered trademark) YELLOW series" and "OPLAS (registered trademark) YELLOW series" (both are trade names, manufactured by Orient Chemical Industry Co., Ltd.).

Specific examples of the yellow dye include C.I. I. Solvent Yellow 14, 16, 32, 33, 43, 44, 93, 94, 98, 104, 114, 116, 133, 145, 157, 163, 164, 167, 181, 182, 183, 184, 185, and 187. C.I. I. Vat Yellow 1, 2 and 3 dyes are commercially available with color indices.

When the laser welded body 10 is required to have fastness such as weather resistance, heat resistance, and bleed resistance, a salt-forming dye obtained by combining an acid dye and an organic amine is suitable as the oil-soluble dye mentioned above. Can be used. Such a salt-forming dye can be represented as [anion/organic ammonium salt of acid dye]. In the colorant, the fastness of the colorant can be improved by replacing the anthraquinone dye with a salt-forming dye and using an anthraquinone-based salt-forming dye represented by [anion/organic ammonium salt of anthraquinonic acid dye]. ..

Specific examples of anthraquinonic acid dyes used in salt-forming dyes include C.I. I. Acid Blue 25, 27, 40, 41, 43, 45, 47, 51, 53, 55, 56, 62, 78, 111, 124, 129, 215, 230, and 277; I. Acid Green 37; C.I. I. Acid Violet 36, 41, 43, 51, and 63 are commercially available under the color indexes of anthraquinone dyes having one sulfonic acid group in one molecule.

Examples of the anthraquinonic acid dye include, in addition to the above, specifically, C.I. I. Acid Blue 23, 35, 49, 68, 69, 80, 96, 129:1, 138, 145, 175, 221, and 344; C.I. I. Acid Green 25, 27, 36, 38, 41, 42, and 44; C.I. I. The anthraquinone dyes having two sulfonic acid groups in one molecule of anthraquinone are commercially available under the color index Acid Violet 34 and 42.

Among them, C.I. I. Acid Blue 49, 80, 96, 129:1, 138, 145, and 221, C.I. I. Acid Green 25, 27, 36, 38, 41, 42, and 44, and C.I. I. As in Acid Violet 34, one having a structure in which a substituent having a sulfonic acid group is bonded to an anilino group is bonded as at least one substituent in the anthraquinone skeleton is preferable.

Suitable anthraquinone salt forming dyes include anthraquinone salt forming dyes having an anilino group derivative as a substituent. Such anthraquinone salt forming dye shows high compatibility with the aromatic thermoplastic resin and can impart high heat resistance.

Such a preferable anthraquinone dye is represented by the following chemical formula (1)
(In the chemical formula (1), X and Y are independently a hydrogen atom, a hydroxyl group, a halogen atom, or an amino group, and R ^{1 to} R ⁵ are independently a hydrogen atom, a hydroxyl group, an amino group, a nitro group, A linear or branched alkyl group having 1 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 18 carbon atoms, a halogen atom, a phenyloxy group, or a carboxy group, and (P) ^b+ is an organic group. Ammonium ion, a and b are positive numbers of 1-2, m and n are positive numbers of 1-2, and A is a hydrogen atom, a hydroxyl group, an amino group, a halogen atom, or the following chemical formula (2).
(In the chemical formula (2), R ^{6 to} R ¹⁰ are independently of each other a hydrogen atom, a hydroxyl group, an amino group, a nitro group, a linear or branched alkyl group having 1 to 18 carbon atoms, and 1 to 18 carbon atoms. A straight-chain or branched-chain alkoxy group or a halogen atom)).

In the chemical formulas (1) and (2), examples of the linear or branched alkyl group having 1 to 18 carbon atoms include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group. , Sec-butyl group, isobutyl group, tert-butyl group, n-pentyl group, neopentyl group, isopentyl group, sec-pentyl group, 3-pentyl group, tert-pentyl group, hexyl group, heptyl group, and octyl group Can be mentioned. Further, as the straight-chain or branched-chain C1-18 alkoxy group having 1 to 18 carbon atoms, for example, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec -Butoxy group, isobutoxy group, tert-butoxy group, n-pentyloxy group, neopentyloxy group, isopentyloxy group, sec-pentyloxy group, 3-pentyloxy group, tert-pentyloxy group, and hexyloxy group Are listed. Further, specific examples of the halogen atom include fluorine, chlorine, bromine, and iodine.

The salt forming dye represented by the chemical formula (1) is preferably an anthraquinone salt forming dye having two phenylamino derivatives as substituents in one molecule. According to this, it is possible to suppress the thermal deterioration of the resin members 1, 2 and 3 due to heat fusion during molding or laser welding. Specific examples of anthraquinonic acid dyes having two phenylamino derivatives as substituents in one molecule, which are preferably used for salt-forming dyes, include C.I. I. Acid Green 25, 27, 36, 38, 41, 42, and 44; C.I. I. Acid Blue 80 and 221; C.I. I. Acid Violet 34 is mentioned.

Specific examples of the amines preferably used in the salt-forming dye represented by the chemical formula (1) include hexylamine, pentylamine, octylamine, 2-ethylhexylamine, di-(2-ethylhexyl)amine, and dodecylamine. Aliphatic amines such as cyclohexylamine, dicyclohexylamine, and dihydroadiethylamine; tetramethylenediamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine, dodecamethylenediamine, 2-methylpentaamine Aliphatic, cycloaliphatic, aromatic diamines such as methylenediamine, 2-methyloctamethylenediamine, trimethylhexamethylenediamine, bis(p-aminocyclohexyl)methane, m-xylenediamine, and p-xylenediamine; 3- Alkoxyalkylamines such as propoxypropylamine, di-(3-ethoxypropyl)amine, 3-butoxypropylamine, octoxypropylamine, and 3-(2-ethylhexyloxy)propylamine; α-naphthylamine, β-naphthylamine. Aromatic amines such as 1,2-naphthylenediamine, 1,5-naphthylenediamine, and 1,8-naphthylenediamine; aromatic alkylamines such as 1-naphthylmethylamine; N-cyclohexylethanolamine , Alkanol group-containing amines such as N-dodecylethanolamine, and N-dodecylimino-diethanol; guanidine derivatives such as 1,3-diphenylguanidine, 1-o-tolylguanidine, and di-o-tolylguanidine. To be

Commercially available quaternary ammonium may be used as the amines. Specific examples of such quaternary ammonium include Coatamine 24P, Coatamine 86P Conc, Coatamine 60W, Coatamine 86W, Coatamine D86P (Distearyldimethylammonium chloride), Sanizole C, and Sanizole B-50 (above, Kao Corporation). Ltd., QUARTAMIN and SANIZOL is a registered trademark); Arquad 210-80E, 2C-75,2HT-75 (dialkyl (alkyl _C 14 _{-C 18)} dimethyl ammonium chloride), 2HT flakes, 2O-75I, 2HP-75 and, 2HP flakes (above, manufactured by Lion Specialty Chemicals Co., Ltd., Arkad is a trade name); Primin MD amine (methanediamine), Primin 81-R (highly branched tert-alkyl (C ₁₂ -C ₁₄ )) Primary amine isomer mixture), primin TOA amine (tert-octylamine), primin RB-3 (tert-alkyl primary amine mixture), and primin JM-T amine (hyperbranched tert-alkyl (C ₁₆ -C _{22 ).} ) Primary amine isomer mixture) (above, Dow Chemical Co., Ltd., PRIMENE is a registered trademark).

The content of the colorant is 0.01 to 3 parts by mass, preferably 0.05 to 1.0 parts by mass, and more preferably 0.1 to 0.8 parts by mass with respect to 100 parts by mass of the thermoplastic resin. Is. By adjusting the content of the colorant in such a range, a highly color-developing weakly laser-absorbing resin composition and a laser-transmissive resin composition can be obtained.

When preparing these resin compositions, it is preferable to prepare a masterbatch containing a colorant and add this masterbatch to the thermoplastic resin composition. According to this, since the colorant is uniformly dispersed, color unevenness does not occur in these resin compositions. The content of the colorant in the masterbatch is preferably 5 to 90% by mass, more preferably 20 to 60% by mass.

Since the laser light transmitting resin composition does not contain the laser light absorbing agent or the content thereof is small, the laser light transmitting resin member 2 is not only an achromatic color but also a chromatic coloring member. can do. For example, the laser light transmissive resin member 2 can be colored yellow, red, blue, green, and purple by using the colorant exemplified above.

In addition to the colorant, various additives may be added to the thermoplastic resin raw material, if necessary, in these resin compositions. Examples of such an additive include a reinforcing material, a filler, an ultraviolet absorber or a light stabilizer, an antioxidant, an antibacterial/mold inhibitor, a flame retardant, an auxiliary colorant, a dispersant, a stabilizer, a plasticizer, Examples include modifiers, antistatic agents, lubricants, release agents, crystallization accelerators, and crystal nucleating agents. Further, white pigments such as titanium oxide, zinc sulfate, zinc white (zinc oxide), calcium carbonate, and alumina white and organic white pigments can be mentioned. According to this, the achromatic thermoplastic resin raw material can be adjusted to a chromatic color by combining it with an organic dye or pigment.

The reinforcing material is not particularly limited as long as it can be used for reinforcing the synthetic resin. For example, glass fibers, carbon fibers, metal fibers, potassium titanate fibers, calcium silicate fibers, sepiolite, wollastonite, and inorganic fibers such as rockwool, and aramids, polyphenylene sulfide resins, polyamides, polyesters, and liquid crystal polymers. Examples of such organic fibers are: For example, when imparting transparency to a resin member, glass fiber can be preferably used to reinforce it. The glass fiber has a fiber length of 2 to 15 mm and a fiber diameter of 1 to 20 μm. The form of the glass fiber is not particularly limited, and examples thereof include roving and milled fiber. These glass fibers may be used alone or in combination of two or more. The content is preferably, for example, 5 to 120 parts by mass with respect to 100 parts by mass of the laser light transmitting resin member 1. When it is less than 5 parts by mass, a sufficient glass fiber reinforcing effect cannot be obtained, and when it exceeds 120 parts by mass, moldability is deteriorated. It is preferably 10 to 60 parts by mass, and particularly preferably 20 to 50 parts by mass.

Examples of fillers include particulate fillers such as talc, kaolin, clay, wollastonite, bentonite, asbestos, and silicates such as alumina silicate; alumina, silicon oxide, magnesium oxide, zirconium oxide, and titanium oxide. Oxides such as; carbonates such as calcium carbonate, magnesium carbonate, and dolomite; sulfates such as calcium sulfate and barium sulfate; glass beads, ceramic beads, boron nitride, and ceramics such as silicon carbide. Are listed. The filler may also be a plate-like filler such as mica, sericite, and glass flakes.

Examples of ultraviolet absorbers and light stabilizers include benzotriazole compounds, benzophenone compounds, salicylate compounds, cyanoacrylate compounds, benzoate compounds, oxazalide compounds, hindered amine compounds, and nickel complex salts.

As an antioxidant, a phenolic compound having a phenolic hydroxyl group, triphenylphosphite, diphenyldecylphosphite, phenyldiisodecylphosphite, tri(nonylphenyl)phosphite, bis(2,4-di-tert-butylphenyl) ) Pentaerythritol diphosphite, phosphorus-containing compounds having a phosphorus atom such as bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, didodecylthiodipropionate, ditetra Decyl thiodipropionate, dioctadecyl thiodipropionate, pentaerythritol tetrakis (3-dodecyl thiopropionate), thiobis(N-phenyl-β-naphthylamine), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetra Examples thereof include sulfur-based compounds and thioether-based compounds having a sulfur atom such as methyl thiuram monosulfide, tetramethyl thiuram disulfide, nickel dibutyl dithiocarbamate, nickel isopropyl xanthate, and trilauryl trithiophosphite.

2-(4'-thiazolyl)benzimidazole, 10,10'-oxybisphenoxyarsine, N-(fluorodichloromethylthio)phthalimide, and bis(2-pyridylthio-1-oxide)zinc are used as antibacterial/antifungal agents. Can be mentioned.

The flame retardant is not particularly limited, and examples thereof include organic flame retardants such as organic halogen compounds, antimony compounds, silicon-containing compounds, phosphorus compounds and nitrogen compounds, and inorganic flame retardants. Examples of the organic halogen compound include brominated polycarbonate, brominated epoxy resin, brominated phenoxy resin, brominated polyphenylene ether resin, brominated polystyrene resin, brominated bisphenol A, pentabromobenzyl polyacrylate, tetrabromobisphenol A derivative, hexa Examples thereof include bromodiphenyl ether and tetrabromophthalic anhydride. Examples of the antimony compound include antimony trioxide, antimony pentoxide, sodium antimonate, and antimony phosphate. Examples of the silicon-containing compound include silicone oil, organic silane, and aluminum silicate. Examples of the phosphorus compound include triphenyl phosphate, triphenyl phosphite, phosphoric acid ester, polyphosphoric acid, ammonium polyphosphate, red phosphorus, and phenoxyphosphazene having a bond between a phosphorus atom and a nitrogen atom in its main chain, and aminophosphazene. The phosphazene compound of is mentioned. Examples of the nitrogen compound include melamine, cyanuric acid, melamine cyanurate, urea, and guanidine. Examples of the inorganic flame retardant include aluminum hydroxide, magnesium hydroxide, silicon compounds, and boron compounds.

The plasticizer is not particularly limited, and examples thereof include phthalic acid esters (eg, dimethyl phthalate, butylbenzyl phthalate, and diisodecyl phthalate), phosphoric acid esters (eg, tricresyl phosphate, and 2-ethylhexyldiphenyl phosphate), sulfones. Examples thereof include amide-based plasticizers (for example, n-butylbenzenesulfonamide, p-toluenesulfonamide, etc.). Furthermore, polyester plasticizers, polyhydric alcohol ester plasticizers, polycarboxylic acid ester plasticizers, bisphenol plasticizers, amide plasticizers, ester plasticizers, amide ester plasticizers, glycerin plasticizers, Further, an epoxy plasticizer (for example, epoxy triglyceride composed of an alkyl epoxy stearate and soybean oil) and the like can be used.

The impact modifier is not particularly limited as long as it has the effect of improving the impact resistance of the resin. For example, known elastomers such as polyamide elastomers, polyester elastomers, styrene elastomers, polyolefin elastomers, acrylic elastomers, polyurethane elastomers, fluorine elastomers, silicone elastomers, and acrylic core/shell elastomers can be cited. To be Of these, polyester elastomers and styrene elastomers are preferable.

Both resin members 1 and 2 may be manufactured using a masterbatch of a desired colored thermoplastic resin composition. Such a masterbatch can be obtained by any method. For example, the powder and/or pellets of the master batch resin and the colorant are mixed in a mixer such as a tumbler or a super mixer, and then heated and melted by an extruder, a batch type kneader or a roll type kneader. Then, it can be obtained by pelletizing or coarsening.

The resin members 1 and 2 can be molded by various procedures that are usually performed. For example, the colored pellets can be molded by a processing machine such as an extruder, an injection molding machine, and a roll mill. Further, transparent thermoplastic resin pellets and/or powder, a pulverized colorant, and various additives as necessary are mixed in a suitable mixer, and the resin composition thus obtained is processed by a processing machine. May be used for molding. Alternatively, for example, a colorant may be added to a monomer containing an appropriate polymerization catalyst, the mixture may be polymerized to synthesize a desired resin, and the resin may be molded by an appropriate method. As a molding method, for example, a molding method such as injection molding, extrusion molding, compression molding, foam molding, blow molding, vacuum molding, injection blow molding, rotational molding, calender molding, and solution casting can be adopted. By such molding, both resin members 1 and 2 having various shapes can be obtained.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

(Preparation of laser-transparent black colorant)
[Colorant A] Anthraquinone blue oil-soluble dye (CI Solvent Blue 104): Perinone red oil-soluble dye (CI Solvent Red 179): Anthraquinone yellow oil-soluble dye (CI Solvent Yellow 163)= Powder mixing was carried out at a ratio of 5:3:2 (mass ratio) to obtain Colorant A.
[Colorant B] Salt-forming dye of anthraquinone blue acid dye (CI Acid Blue 80) and hexamethylenediamine: Perinone red oil-soluble dye (CI Solvent Red 179): Anthraquinone yellow oil-soluble dye (C) I. Solvent Yellow 163)=7:2:1 (mass ratio) by powder mixing to obtain Colorant B.
[Colorant C] Salt-forming dye of anthraquinone blue acid dye (CI Acid Blue 80) and 2-ethylhexylamine: Perinone red oil-soluble dye (CI Solvent Red 179: anthraquinone yellow oil-soluble dye (C I. Solvent Yellow 163)=7:2:1 (mass ratio) by powder mixing to obtain Colorant C.
[Colorant D] Salt forming dye of anthraquinone blue acid dye (CI Acid Blue 236) and 2-ethylhexylamine: Perinone red oil-soluble dye (CI Solvent Red 179): Anthraquinone yellow oil-soluble dye ( C. I. Solvent Yellow 163)=6:3:1 (mass ratio) by powder mixing to obtain Colorant D.
[Colorant E] Anthraquinone blue oil-soluble dye (CI Solvent Blue 104) was used as a colorant E.
[Colorant F] A salt forming dye of anthraquinone blue acid dye (CI Acid Blue 80) and 2-ethylhexylamine was used as a colorant F.

(Example 1-1)
(1) Manufacture of laser light weakly absorbing resin member 1 (first resin member) 499.9 g of polyamide (PA) 66 resin (manufactured by Asahi Kasei Corporation, trade name: Leona (registered trademark) 1300S) and Nigrosine A ( Nigrosine sulfate synthesized by changing the concentration of sulfuric acid according to the description of Japanese Patent No. 3757081; 1.96 mass% of sulfate ion; 0.1 g of volume resistivity of 2.0×10 ¹⁰ Ω·cm) and stainless steel The mixture was placed in a tumbler and mixed with stirring for 1 hour. The obtained mixture was molded by an ordinary method at a cylinder temperature of 290° C. and a mold temperature of 80° C. by using an injection molding machine (manufactured by Toyo Kikai Kinzoku Co., Ltd., product name: Si-50), and a length of 80 mm× One sheet of weakly laser-absorptive resin member 1 in the shape of a rectangular plate having a width of 50 mm and a thickness of 1 mm was prepared.

(2) Preparation of Laser Light Transmittable Resin Member 2 (Second Resin Member) 490 g of PA66 resin and 10 g of colorant A were placed in a stainless steel tumbler and mixed with stirring for 1 hour. The obtained mixture was molded by an ordinary method at a cylinder temperature of 290° C. and a mold temperature of 80° C. by using an injection molding machine (manufactured by Toyo Kikai Kinzoku Co., Ltd., product name: Si-50), and a length of 80 mm× One rectangular plate-shaped laser light transmitting resin member 2 having a width of 50 mm and a thickness of 1 mm was prepared.

(Transmittance and absorbance)
The transmittance and reflectance of the molded plate of the laser light absorbing resin member and the weak laser light absorbing resin member were measured using a spectrophotometer (manufactured by JASCO Corporation, trade name: V-570). A general absorbance (Absorbance) measured by dissolving a sample is a positive number obtained by taking the logarithm of the transmittance. When measuring the absorbance of a molded resin member as in the present invention, since the laser light is reflected on the surface of the molded plate, it is necessary to determine the true transmittance. True transmittance T _is represented by _{T = I T / (I 0} -I R). The Lambert-Beer law showing the absorbance at 940 nm is represented by the following mathematical formula (1).
(In Formula (1), T is the true transmittance, _{(I O)} is the incident light intensity, _{(I T)} is the transmitted light intensity, _{(I R)} is reflected light intensity) in expressed. Here, by setting the incident light intensity I _O to 100%, and further substituting the transmitted light intensity I _T and the reflected light intensity I _R , the transmittance and the reflectance, which are percentages of the measured values, in the mathematical expression (1), respectively, The absorbance was determined, and this value was divided by the thickness of the resin member to calculate the absorbance a per mm. As a result, the laser light weakly absorbing resin member 1 of Example 1-1 had a transmittance of 68.6%, a reflectance of 8.2%, and an absorbance a ₁ of ₁ mm of 0.12. It was Further, the transmittance of the laser light transmissive resin member 2 was 80.1%, the reflectance was 9.9%, and the absorbance a _{2 in} terms of 1 mm was 0.06.

(Melt flow rate)
The weakly laser-absorbing resin member 1 was cut into a predetermined size and dried at 80° C. for 15 hours to prepare a measurement sample. According to JIS K7210:2014 (Plastics-Method for determining melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics), Melt Indexer F-F01 type (trade name, manufactured by Toyo Seiki Seisakusho Co., Ltd.) is used. It was measured under the conditions of a test temperature of 280° C. and a test load of 2.16 kgf. The measurement was performed 3 times, the average of those values was calculated, and the melt flow rate was calculated|required. As a result, the melt flow rate of the laser light weakly absorbing resin member 1 was 13.4 g/10 minutes.

(3) Preparation of Laser-Welded Article 10 As shown in FIG. 1, the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 are overlapped to form a unit in the thickness direction of both the resin members 1 and 2. A pressure of 0.4 Pa per area was applied. Further, a glass plate (laser light transmittance 90%) having a thickness of 5 mm was placed on the surface of the weakly laser light absorbing resin member 1 to fix the three-layer resin member. Then, laser light L from a diode laser [wavelength: 940 nm continuous] (manufactured by Hamamatsu Photonics KK) having an output of 50 W is supplied from above the weakly laser light absorbing resin member 1 substantially perpendicularly to the surface thereof. Irradiation was performed while scanning at a width of 1 mm, a scanning speed of 2.0 mm/sec, and a scanning distance of 20 mm so as to traverse a straight line from one of the long sides. As a result, the laser welded body 10 of Example 1-1 in which the resin portions 1 and 2 were integrated by welding at the contact portion C was obtained. The following evaluation was performed on the laser welded body 10.

(Tensile test)
According to JIS K7161:2014 plastic-tensile property test method, both resin members 1 and 2 of the laser welded body 10 are longitudinally aligned using a tensile tester (manufactured by Shimadzu Corporation, trade name: AG-50kNE). Then, they were pulled horizontally at a test speed of 10 mm/min so as to separate from each other, and the tensile strength was measured. The results are shown in Table 1.

(Evaluation of welding state)
The welded state was evaluated as follows. The results are shown in Table 1.
Good: Laser welding was possible, and the result of the tensile test of the laser welded body was 400 N or more.
Δ: Laser welding was possible, but the result of the tensile test of the laser welded body was less than 400N.
X: Laser welding was not possible and a laser welded body could not be produced.

(Example 1-2)
(1) Preparation of weakly laser-absorbing resin member 1 499.8 g of PA66 resin and nigrosine A (sulfate of nigrosine; sulfate ion 1.96% by mass; volume resistivity 2.0×10 ¹⁰ Ω·cm) Laser light transmissive resin member 1 was produced in the same manner as in Example 1-1, except that 0.2 g of the above was used. When the transmittance and the reflectance of this laser light transmissive resin member 1 were measured in the same manner as in Example 1-1, the transmittance was 52.6% and the reflectance was 7.0%. .. The absorbance a ₁ obtained from these was 0.24. The melt flow rate measured by operating in the same manner as in Example 1-1 was 14.3 g/10 minutes.
(2) Preparation of Laser Light Transmitting Resin Member 2 Laser light transmitting resin member 2 was operated in the same manner as in Example 1-1 except that 500 g of PA66 resin was used and no coloring agent was used. Was prepared. When the transmittance and reflectance of this laser light transmitting resin member 1 were measured in the same manner as in Example 1-1, the transmittance was 80.3% and the reflectance was 9.6%. .. The absorbance a ₂ obtained from these was 0.05.
(3) Preparation of Laser-Welded Body 10 The laser-welded body 10 of Example 1-2 was operated in the same manner as in Example 1-1, except that the laser output and scanning speed were changed as shown in Table 1. Obtained. The laser welded body 10 was operated in the same manner as in Example 1 to perform a tensile test and a welded state evaluation. The results are shown in Table 1.

(Example 1-3)
(1) Preparation of weakly laser-absorbing resin member 1 499.7 g of PA66 resin and nigrosine B (sulfate of nigrosine; sulfate ion 1.52% by mass; volume resistivity 2.7×10 ¹⁰ Ω·cm) Laser light transmitting resin member 1 was produced in the same manner as in Example 1-1, except that 0.3 g was used. When the transmittance and reflectance of this laser light transmissive resin member 1 were measured in the same manner as in Example 1-1, the transmittance was 39.2% and the reflectance was 5.9%. .. The absorbance a ₁ obtained from these was 0.36. The melt flow rate measured by operating in the same manner as in Example 1-1 was 14.8 g/10 minutes.
(2) Manufacture of Laser Light-Transmissive Resin Member 2 In the same manner as in Example 1-2, one laser light transmissive resin member 2 was manufactured.
(3) Preparation of Laser-Welded Body 10 The laser-welded body 10 of Example 1-3 was operated in the same manner as in Example 1-1, except that the laser output and scanning speed were changed as shown in Table 1. Obtained. The laser welded body 10 was operated in the same manner as in Example 1 to perform a tensile test and a welded state evaluation. The results are shown in Table 1.

(Example 1-4)
(1) Production of weakly laser-absorbing resin member 1 499.6 g of PA66 resin and nigrosine C (sulfate of nigrosine; sulfate ion 0.70 mass%; volume resistivity 0.9×10 ¹⁰ Ω·cm) Laser light transmissive resin member 1 was produced in the same manner as in Example 1-1, except that 0.4 g of was used. When the transmittance and reflectance of this laser light transmitting resin member 1 were measured by operating in the same manner as in Example 1-1, the transmittance was 32.2% and the reflectance was 5.3%. .. The absorbance a ₁ obtained from these was 0.45. The melt flow rate measured by operating in the same manner as in Example 1-1 was 15.4 g/10 minutes.
(2) Manufacture of Laser Light-Transmissive Resin Member 2 In the same manner as in Example 1-2, one laser light transmissive resin member 2 was manufactured.
(3) Preparation of Laser Welded Body 10 The laser welded body 10 of Example 1-4 was operated in the same manner as in Example 1-1, except that the laser output and scanning speed were changed as shown in Table 1. Obtained. The laser welded body 10 was operated in the same manner as in Example 1 to perform a tensile test and a welded state evaluation. The results are shown in Table 1.

(Examples 1-5 to 1-12 and Comparative examples 1-1 to 1-5)
Except that the amount of PA66 resin, the amount of nigrosine A, and the type and amount of the colorant were changed as shown in Table 1, the same operation as in Example 1-1 was carried out, and Examples 1-5 to 1- No. 12 and Comparative Examples 1-1 to 1-5 were used to prepare a resin member used for preparing the laser-welded body, and the transmittance and the reflectance were measured in the same manner as in Example 1-1 to measure the absorbance. I asked. Furthermore, the melt flow rates of Examples 1-5, 1-7, and 1-9 were measured in the same manner as in Example 1-1. Also, using this resin member, the laser welded product of Examples 1-5 to 1-12 was operated in the same manner as in Example 1-1, except that the laser output and scanning speed were changed as shown in Table 1. Was produced. Further, with respect to these laser welded bodies, a tensile test and a welded state were evaluated by operating in the same manner as in Example 1-1. On the other hand, laser light was irradiated to the resin members of Comparative Examples 1-1 to 1-5 which were operated and laminated in the same manner as in Example 1-1, but the resin members were not welded to each other to obtain a laser welded body. I couldn't. The results of Examples 1-5 to 1-12 are shown in Table 1 together with Examples 1-1 to 1-4, and the results of Comparative Examples 1-1 to 1-5 are shown in Table 2.

Laser light weakly absorbing resin member 1 having an absorbance a _{1 of} 0.1 to 0.5 and a laser light transmitting resin member having an absorbance a ₂ of less than 0.1 (specifically 0.01 to 0.09). The laser-welded bodies of the examples in which No. 2 and No. 2 were welded by irradiation with a laser beam having a relatively low output had no welding marks and had high tensile strength. On the other hand, in the comparative example using the laser light transmissive resin member having the absorbance a _{1 of} less than 0.1, the resin members could not be welded to each other even when irradiated with the high output laser light. Further, in the comparative example using the laser light weakly absorbing resin member having the absorbance a ₁ of more than 0.5, the laser light irradiation shows a scorched mark on the surface layer of the laser light weakly absorbing resin member or the spread of the molten pool. Was insufficient and high strength welding was not possible.

8A is an enlarged cross-sectional photograph of the fusion-bonded portion of Example 1-3, and FIG. 8B is the enlarged photograph of the fusion-bonded portion of the laser-welded body 10 of Example 1-4. The white arrows in the figure indicate the irradiation direction and position of the laser light. The molten portion having a substantially elliptical cross section spreads largely on the laser light weakly absorbing resin member 1 arranged on the laser light incident side, and passes through a contact portion C between this and the laser light transmitting resin member 2 and the laser light. It reaches the transparent resin member 2. Thereby, both resin members 1 and 2 are welded and integrated. Since this welded portion spreads to the laser light weakly absorbing resin member 1 side rather than the laser light transmitting resinous member 2, the laser light weakly absorbing resin member 1 melts in a wider and deeper range by the laser light irradiation. It was found that a molten pool formed was formed.

(Example 2-1)
(1) Preparation of laser light weakly absorbing resin member 1 499.5 g of polypropylene (PP) resin (manufactured by Prime Polymer Co., Ltd., trade name: J-762HP) and Nigrosine (manufactured by Orient Chemical Industry Co., Ltd., trade name: NUBIAN (Registered trademark) Gray IR-B CI Solvent Black 7 high heat-resistant nigrosine; 0.5 g of volume resistivity 1.2×10 ¹¹ Ω·cm) was placed in a stainless steel tumbler and stirred for 1 hour. Mixed. The obtained mixture was molded by an ordinary method at a cylinder temperature of 210° C. and a mold temperature of 40° C. using an injection molding machine (manufactured by Toyo Kikai Kinzoku Co., Ltd., trade name: Si-50), and a length of 80 mm× One sheet of weakly laser-absorbing resin member 1 having a width of 50 mm and a thickness of 1.5 mm was prepared.

(2) Preparation of laser light transmitting resin member 2 500 g of PP resin was molded by an ordinary method at a cylinder temperature of 210° C. and a mold temperature of 40° C. using an injection molding machine, and a length of 80 mm×width of 50 mm× One laser light transmitting resin member 2 having a thickness of 1.5 mm was produced.

By operating in the same manner as in Example 1-1, the transmittance of the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 was measured to obtain the absorbance. The results are shown in Table 3.

(3) Preparation of Laser-Welded Article 10 As shown in FIG. 1, the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 are overlapped to form a unit in the thickness direction of both the resin members 1 and 2. A pressure of 0.4 Pa per area was applied. Further, a glass plate (laser light transmittance 90%) having a thickness of 5 mm was placed on the surface of the weakly laser light absorbing resin member 1 to fix the three-layer resin member. Then, laser light L from a diode laser [wavelength: 940 nm continuous] (manufactured by Fine Devices Co., Ltd.) having an output of 50 W is provided from above the weakly laser light absorbing resin member 1 substantially perpendicularly to the surface thereof. Irradiation was performed while scanning at a width of 1 mm, a scanning speed of 2.0 mm/sec, and a scanning distance of 20 mm so as to traverse a straight line from one of the long sides. As a result, the laser welded body 10 of Example 2-1 in which the two resin members 1 and 2 were integrated by welding at the contact portion C was obtained. The laser welded body 10 was operated in the same manner as in Example 1-1, and the tensile test and the welded state were evaluated. The results are shown in Table 3.

(Examples 2-2 and 2-3)
A resin member used for producing the laser-welded bodies of Examples 2-2 and 2-3 was operated in the same manner as in Example 2-1, except that the amount of nigrosine was changed as shown in Table 3. It produced by operating similarly to Example 2-1 and measured the transmittance|permeability of them, and calculated|required the light absorbency. Further, using this resin member, the laser welded bodies of Examples 2-2 and 2-3 were operated in the same manner as in Example 2-1 except that the scanning speed of laser light was changed as shown in Table 3. 10 was produced. Further, the same operation as in Example 2-1 was performed to perform a tensile test and evaluation of the welded state. The results are shown in Table 3.

(Example 2-4)
(1) Production of weakly laser-absorbing resin member 1 The same operation as in Example 2-1 except that the amount of PP resin was 498.0 g and the amount of nigrosine was 2.0 g. A sheet of weakly laser-absorbing resin member 1 was prepared.

(2) Preparation of Laser-Transparent Resin Member 2 495.0 g of PP resin and 5.0 g of colorant A were placed in a stainless tumbler and mixed with stirring for 1 hour. The obtained mixture was molded by an ordinary method using an injection molding machine at a cylinder temperature of 210° C. and a mold temperature of 40° C., and had a rectangular plate-like laser light transmittance of 80 mm length×50 mm width×1 mm thickness. One resin member 2 was produced.

By operating in the same manner as in Example 2-1, the transmittances of the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 were measured to determine the absorbance. The results are shown in Table 3.

(3) Preparation of Laser Welded Body 10 Using the laser light weakly absorbing resin member 1 and the laser light transmissive resin member 2, the laser welded body 10 of Example 2-4 was operated in the same manner as in Example 2-1. Was produced. Further, the same operation as in Example 2-1 was performed to perform a tensile test and evaluation of the welded state. The results are shown in Table 3.

(Comparative example 2)
A weakly laser absorptive resin member was manufactured in the same manner as in Example 2-1 except that nigrosine was not used and 500 g of PP resin was used. Further, a laser light transmitting resin member was produced by performing the same operation as in Example 2-1. By operating in the same manner as in Example 2-1, the transmittance of these resin members was measured and the absorbance was determined. Further, laser light was irradiated to these resin members which were superposed by operating in the same manner as in Example 2-1, but the resin members were not welded to each other and a laser welded body could not be obtained. The results of Comparative Example 2 are shown in Table 3.

The laser-welded bodies 10 of Examples 2-1 to 2-4 using the weakly laser-absorbing resin member 1 having the absorbance a _{1 of} 0.1 to 0.5 have no welding marks and have high strength. A good welded state was shown in which the members were welded to each other. On the other hand, in Comparative Example 2 in which the resin member having the absorbance a ₁ of less than 0.1 was used, the resin members could not be welded to each other by the laser light irradiation.

(Example 3-1)
(1) Manufacture of laser light weakly absorbing resin member 1 Polybutylene terephthalate (PBT) resin (manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: Novaduran (registered trademark) 5010G30) and 499.99 g of Nigrosine (Orient Chemical Industries Co., Ltd., trade name: NUBIAN (registered trademark) BLACK TH-807 CI Solvent Black 7; 0.01 g of volume resistivity 4.0×10 ¹⁰ Ω·cm) is put in a stainless steel tumbler, Stir and mix for 1 hour. The obtained mixture is molded by an ordinary method at a cylinder temperature of 250° C. and a mold temperature of 80° C. by using an injection molding machine (manufactured by Toyo Kikai Kinzoku Co., Ltd., trade name: Si-50), and a length of 80 mm× One sheet of weakly laser-absorbing resin member 1 having a width of 50 mm and a thickness of 1.5 mm was prepared.

(2) Preparation of Laser Light-Transmissive Resin Member 2 500.0 g of PBT resin was placed in a stainless tumbler and stirred for 1 hour. This is molded by an ordinary method using an injection molding machine at a cylinder temperature of 250° C. and a mold temperature of 80° C. to form a laser light transmitting resin member 2 having a length of 80 mm×a width of 50 mm×a thickness of 1.5 mm. One sheet was prepared.

By operating in the same manner as in Example 1-1, the transmittances of the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 were measured to obtain the absorbance. The results are shown in Table 4.

(3) Preparation of Laser-Welded Article 10 As shown in FIG. 1, the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 are overlapped to form a unit in the thickness direction of both the resin members 1 and 2. A pressure of 0.4 Pa per area was applied. Further, a glass plate (laser light transmittance 90%) having a thickness of 5 mm was placed on the surface of the weakly laser light absorbing resin member 1 to fix the three-layer resin member. Then, laser light L from a diode laser [wavelength: 940 nm continuous] (manufactured by Fine Devices Co., Ltd.) having an output of 50 W is provided from above the weakly laser light absorbing resin member 1 substantially perpendicularly to the surface thereof. Irradiation was performed while scanning at a width of 1 mm, a scanning speed of 2.0 mm/sec, and a scanning distance of 20 mm so as to traverse a straight line from one of the long sides. As a result, the laser welded body 10 of Example 3-1 in which the two resin members 1 and 2 were integrated by welding at the contact portion C was obtained. The laser welded body 10 was operated in the same manner as in Example 1-1, and the tensile test and the welded state were evaluated. The results are shown in Table 4.

(Example 3-2)
Except that the amount of nigrosine was changed as shown in Table 4, the same operation as in Example 3-1 was carried out to prepare a resin member used for preparing the laser-welded body of Example 3-2, and the execution was performed. By operating in the same manner as in Example 3-1, their transmittances were measured and the absorbance was determined. Further, using this resin member, the laser welded body 10 of Example 3-2 was produced in the same manner as in Example 3-1 except that the scanning speed of laser light was changed as shown in Table 4. .. Further, the same operation as in Example 3-1 was performed to perform a tensile test and evaluation of the welded state. The results are shown in Table 4.

(Example 3-3)
(1) Fabrication of Weakly Absorbent Laser Light Absorbing Resin Member 1 By the same operation as in Example 3-1, one weakly laser light absorbing resin member 1 was fabricated.

(2) Preparation of Laser Light Transmittable Resin Member 2 497.0 g of PBT resin and 3.0 g of colorant A were put in a stainless steel tumbler and mixed with stirring for 1 hour. The obtained mixture was molded by an ordinary method using an injection molding machine at a cylinder temperature of 250° C. and a mold temperature of 80° C., and a rectangular plate-shaped laser light transmissivity of 80 mm long×50 mm wide×1 mm thick. One resin member 2 was produced.

By operating in the same manner as in Example 3-1, the transmittance of the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 was measured to obtain the absorbance. The results are shown in Table 5.

(3) Preparation of Laser Welded Body 10 Using the laser light weakly absorbing resin member 1 and the laser light transmissive resin member 2, the laser welded body 10 of Example 3-3 was operated in the same manner as in Example 3-1. Was produced. Further, the tensile test and the welded state were evaluated by operating in the same manner as in Example 1-1. The results are shown in Table 4.

(Comparative example 3)
A weak laser light absorbing resin member was produced in the same manner as in Example 3-1, except that nigrosine was not added and 500 g of the PBT resin was used. Further, a laser light transmissive resin member was produced in the same manner as in Example 3-1. By operating in the same manner as in Example 3-1, the transmittance of these resin members was measured to obtain the absorbance. Further, laser light was irradiated to these resin members which were superposed by operating in the same manner as in Example 3-1, but the resin members were not welded to each other and a laser welded body could not be obtained.
The results of Comparative Example 3 are shown in Table 4.

The laser welded bodies 10 of Examples 3-1 to 3-3 using the laser light weakly absorbing resin member 1 having the absorbance a _{1 of} 0.1 to 0.5 have no welding marks and are in a good welded state. showed that. On the other hand, in Comparative Example 3 in which the resin member having the absorbance a ₁ of less than 0.1 was used, the resin members could not be welded to each other by laser light irradiation.

(Example 4-1)
(1) Manufacture of laser light weakly absorbing resin member 1 499.9 g of polycarbonate (PC) resin (manufactured by Teijin Limited, trade name: Panlite (registered trademark) 1225Y) and modified nigrosine (alkylbenzene sulfonic acid: as nigrosine) Nigrosine = 20:80 (mass ratio) 0.1 g of mixed nigrosine CI Solvent Black 5) was placed in a stainless steel tumbler and mixed with stirring for 1 hour. The obtained mixture was molded by an ordinary method at a cylinder temperature of 300° C. and a mold temperature of 100° C. using an injection molding machine (manufactured by Toyo Kikai Metal Co., Ltd., trade name: Si-50), and a length of 80 mm× One weak laser light absorbing resin member 1 having a width of 50 mm and a thickness of 2 mm was produced.

(2) Preparation of laser light transmitting resin member 2 500.0 g of PC resin was placed in a stainless steel tumbler and stirred for 1 hour. This is molded by an ordinary method at a cylinder temperature of 250° C. and a mold temperature of 80° C. using an injection molding machine to produce one laser light transmitting resin member 2 having a length of 80 mm×a width of 50 mm×a thickness of 2 mm. did.

By operating in the same manner as in Example 1-1, the transmittance of the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 was measured to obtain the absorbance. The results are shown in Table 5.

(3) Preparation of Laser-Welded Article 10 As shown in FIG. 1, the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 are overlapped to form a unit in the thickness direction of both the resin members 1 and 2. A pressure of 0.4 Pa per area was applied. Further, a glass plate (laser light transmittance 90%) having a thickness of 5 mm was placed on the surface of the weakly laser light absorbing resin member 1 to fix the three-layer resin member. Then, laser light L from a diode laser [wavelength: 940 nm continuous] (manufactured by Fine Devices Co., Ltd.) having an output of 50 W is provided from above the weakly laser light absorbing resin member 1 substantially perpendicularly to the surface thereof. Irradiation was performed while scanning at a width of 1 mm, a scanning speed of 2.0 mm/sec, and a scanning distance of 20 mm so as to traverse a straight line from one of the long sides. Thereby, the laser welded body 10 of Example 4-1 in which the resin members 1 and 2 were integrated by welding at the contact portion C was obtained. The laser welded body 10 was operated in the same manner as in Example 1-1, and the tensile test and the welded state were evaluated. The results are shown in Table 5.

(Example 4-2)
The amount of the PC resin was 499.75 g, and 0.25 g of modified nigrosine (mixed nigrosine CI Solvent Black 5 of alkylbenzene sulfonic acid:nigrosine=30:70 (mass ratio)) was used as nigrosine. Except for this, the laser light weakly absorbing resin member 1 was produced in the same manner as in Example 4-1. Further, the same operation as in Example 4-1 was carried out to produce the laser light transmitting resin member 2. By operating in the same manner as in Example 4-1, the transmittance of the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 was measured to obtain the absorbance. The results are shown in Table 5.

The same operation as in Example 4-1 was carried out to obtain the laser-welded product 10 of Example 4-2. The laser welded body 10 was operated in the same manner as in Example 4-1, and a tensile test and a welded state were evaluated. The results are shown in Table 5.

(Example 4-3)
First, the laser light weakly absorbing resin member 1 was manufactured by performing the same operation as in Example 4-1. Then, 490.0 g of the PC resin and 10 g of the colorant E (anthraquinone blue oil-soluble dye, CI Solvent Blue 104) were placed in a stainless steel tumbler and mixed with stirring for 1 hour. Using the obtained mixture, the same operation as in Example 4-1 was carried out to produce a laser light transmissive resin member 2. By operating in the same manner as in Example 4-1, the transmittance of the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2 was measured to obtain the absorbance. The results are shown in Table 5.

The same operation as in Example 4-1 was carried out to obtain the laser welded body 10 of Example 4-3. The laser welded body 10 was operated in the same manner as in Example 4-1, and a tensile test and a welded state were evaluated. The results are shown in Table 5.

(Comparative Example 4)
499.975 g of PC resin and 0.025 g of modified nigrosine as nigrosine were put in a stainless steel tumbler and mixed with stirring for 1 hour. Otherwise, the same operation as in Example 4-1 was carried out to produce a weakly laser-absorbing resin member. Further, the same operation as in Example 4-1 was carried out to produce a laser light transmissive resin member. By operating in the same manner as in Example 4-1, the transmittance of these resin members was measured to obtain the absorbance. Further, laser light was irradiated to these resin members which were superposed by operating in the same manner as in Example 4-1, but the resin members were not welded to each other and a laser welded body could not be obtained.
The results of Comparative Example 4 are shown in Table 5.

The laser-welded bodies 10 of Examples 4-1 to 4-3 using the weakly laser-absorbing resin member 1 having the absorbance a ₁ of 0.1 or 0.25 have no welding marks and are in a good welded state. showed that. On the other hand, in Comparative Example 4 in which the resin member having the absorbance a ₁ of less than 0.1 was used, the resin members could not be welded to each other by the laser light irradiation.

(Example 5-1)
(1) Fabrication of laser light weakly absorbing resin member 499.8 g of polyamide (PA) 66 resin (manufactured by Asahi Kasei Corporation, trade name: Leona (registered trademark) 1300S) and Nigrosine A (as described in Japanese Patent No. 3757081). Nigrosine sulfate synthesized by changing the concentration of sulfuric acid; sulfate ion 1.96% by mass; 0.2 g of volume resistivity 2.0×10 ¹⁰ Ω·cm) was placed in a stainless steel tumbler and stirred for 1 hour. Mixed. The obtained mixture was molded by an ordinary method at a cylinder temperature of 270° C. and a mold temperature of 60° C. using an injection molding machine (manufactured by Toyo Kikai Kinzoku Co., Ltd., product name: Si-50), and is a perspective view. As shown in FIG. 9(a), a lid 8 which is a laser light weakly absorbing resin member having a disk-shaped head portion 8a and a cylindrical sleeve portion 4b coaxial with the head portion 8a. Was produced. The outer dimensions of the head portion 8a are an outer diameter of 50 mm and a thickness of 2 mm. The outer dimensions of the sleeve portion 8b are an outer diameter of 42 mm and a height of 4 mm. The lid 8 has a step portion 8c having a width of 4 mm on its outer peripheral surface due to the difference in outer diameter between the head portion 8a and the sleeve portion 8b.

(2) Preparation of laser light transmitting resin member 500.0 g of PA66 resin was put into a stainless steel tumbler and stirred for 1 hour. This was molded by an ordinary method using an injection molding machine at a cylinder temperature of 270° C. and a mold temperature of 60° C., and a circular bottom and a peripheral edge of the bottom as shown in FIG. A cylindrical container 7 having a peripheral wall portion extending toward and an opening edge 7a opened at the upper end of the peripheral wall portion and being a laser light transmissive resin member was manufactured. The outer size of the cylindrical container 7 is 50 mm in outer diameter×35 mm in height, and the inner size thereof is 43 mm in inner diameter×32 mm in height. The cylindrical container 7 has a wall thickness of 3 mm.

By operating in the same manner as in Example 1-1, the transmittance of the lid 8 which is the laser light absorbing resin member and the cylindrical container 7 which is the laser light transmitting resin member was measured to obtain the absorbance. The results are shown in Table 6.

(3) Preparation of Laser Welded Body The sleeve portion 8b of the lid 8 was inserted into the inner space of the cylindrical container 7 from the opening edge 7a, and the lid 8 and the cylindrical container 7 were fitted together by hand. As a result, as shown in FIG. 9B, which is a partially enlarged vertical cross-sectional view of the lid 8 and the cylindrical container 7, the contact portion C where the step portion 8c and the opening edge 7a overlap and contact with each other, and the sleeve. A butt portion B where the portion 8b and the inner wall surface of the cylindrical container 7 were butted was formed. The butt portion B is formed by the dimensional difference between the outer diameter of the sleeve portion 8b and the inner diameter of the cylindrical container 7 and the deviation of the central axes of the fitted lid 8 and cylindrical container 7 from each other. 7 has a surface contact with the inner wall surface and a part having a slight play (gap).

A laser beam L is emitted from a diode laser [wavelength: 940 nm continuous] (manufactured by Hamamatsu Photonics KK) with an output of 50 W toward the contact portion C from above the lid body 4 substantially perpendicularly to the contact portion. Irradiation was performed while scanning at a scanning speed of 2.0 mm/sec so that a circle was drawn along C. As a result, the laser welded body 10 of Example 5-1 was obtained in which the lid portion 8 and the cylindrical container 7 were integrated by welding at the contact portion C. The welded state of this laser welded body 10 was evaluated in the same manner as in Example 1-1. The results are shown in Table 6.

(Example 5-2)
(1) Production of weakly laser-absorbing resin member The procedure of Example 5-1 was repeated, except that the amount of PA66 resin was 499.7 g and the amount of nigrosine was 0.3 g. The lid 8 shown in FIG. 9A was produced.

(2) Preparation of laser light transmissive resin member The procedure of Example 5-1 was repeated, except that the amount of PA66 resin was 497.0 g, and the colorant C was 3.0 g. The cylindrical container 7 shown in FIG. 9A was produced.

The transmittance and the absorbance of the lid body 8 which is a laser light absorbing resin member and the cylindrical container 7 which is a laser light transmitting resin member were measured by operating in the same manner as in Example 5-1. The results are shown in Table 6.

(3) Preparation of laser welded body The laser welded body 10 of Example 5-2 was obtained in the same manner as in Example 5-1 except that the scanning speed of the laser light L was 3.0 mm/sec. It was The welded state of this laser welded body 10 was evaluated in the same manner as in Example 5-1. The results are shown in Table 6.

As shown in Table 6, the laser welded body 10 is satisfactorily laser welded at the abutting portion B between the lid 8 and the cylindrical container 7, so that the inside of the cylindrical container 7 is reliably sealed. It was

The laser welded body of the present invention is, for example, an instrument panel for interior, a resonator (silencer) in an engine room, an engine cover, a drive unit, a brake unit, a vehicle lighting unit, a transportation device such as an electrical component ( Especially for automobiles), electrical and electronic equipment parts, industrial machine parts, medical tubes used for infusion of liquids and nutrients, food packaging materials such as spout pouches containing liquid food and beverage compositions. Since it can be suitably and widely applied to household appliance parts such as PET bottle labels and housings, it is extremely useful in industry.

Reference numeral 1 is a weakly laser light absorbing resin member, 1a and 1b are weakly laser light absorbing resin member pieces, 1c is a first joint portion, 2 is a laser light transmitting resin member, and 2a and 2b are laser light transmitting resin members. Pieces 2c are second joint parts, 3 is a resin bottle, 4 is a label, 5a and 5b are cylindrical members, 6 is a belt-shaped member, 7 is a cylindrical container, 7a is an opening edge, 8 is a lid, and 8a. sleeves the head, 8b is, 8c is stepped portion, a laser-welded article 10, B butt site, _{B 1} is an upper butt portion, _{B 2} a portion abutting the lower, C is contact sites, L is a laser beam, N is a contact part, N ₁ is a first contact part, N ₂ is a second contact part, and X and Y are directions.

Claims (14)

A first resin member that is a laser light irradiation side resin member that contains a thermoplastic resin and nigrosine and has an absorbance a _{1 of} 0.1 to 0.5; and a thermoplastic resin that is the same or different from the thermoplastic resin. And a _second resin member containing 0.01 to 0.098 of absorptivity a ₂ is laser-welded at at least a part of the contact portion formed by overlapping, and the absorptivity a ₁ the absorbance laser-welded article absorbance ratio _a 1 / _{a 2} is characterized by from 1.3 to 45 der Rukoto between _{a 2} and. The content of the nigrosine in the first resin member is 0.01 to 0.2% by mass, and the volume resistivity of the nigrosine is 0.5×10 ^{9 to} 5.0×10 ¹¹ Ω·cm . The laser welded body according to claim 1, wherein At least a portion of said contact portion being laser welding, according to claim 1 or 2 than the second resin member, characterized that you have a fused portion spread on the first resin member side Laser welded material. Nigrosine is nigrosine sulfate, laser-welded article according to any one of claims 1-3 in which the sulfate ion concentration of the nigrosine sulfate and wherein 0.3 to 5% by mass Rukoto. The melt flow rate of the first resin member, the laser-welded article according to any one of 4 from claim 1, wherein the Oh Rukoto in 11~30g / 10 min. The absorbance _{a 2} is laser-welded article according to claim 1, wherein the 5 to be 0.01 to 0.09. At least a part of the contact portion formed by the end portions of the first resin member and/or the end portions of the second resin member being in contact with each other, the end portions being laser It is welded , The laser welded body in any one of Claim 1 to 6 characterized by the above-mentioned. Wherein the first resin member and / or said second resin member, the laser-welded article according to claim 7, characterized that you have been divided into a plurality of resin piece in contact said at contact sites. The second resin member is divided into two resin member pieces, and the absorbance a _2-1 and the absorbance a _2-2 thereof are 0.05 to 0.09, and the absorbance a ₁ and the absorbance a are wherein the absorbance ratio of _{2-1 a} 1 _{/ a 2-1,} or absorbance ratio _a 1 _{/ a 2-2} with the absorbance _{a 1} and the absorbance _{a 2-2,} a 1.3 to 45 The laser welded body according to claim 8 . Said first resin member and the second resin member, to claim 1, wherein 9 of that you have a butt portion is formed by being butted at their ends The laser welded product described. The second resin member, the laser-welded article according to any one of claims 1 to 10, characterized in that it contains a colorant and / or nigrosine anthraquinone. The thermoplastic resin is at least one selected from a polyamide resin, a polycarbonate resin, a polyphenylene sulfide resin, a polyethylene terephthalate resin, a polybutylene terephthalate resin, and a polypropylene resin, according to any one of claims 1 to 11. The laser welded product described. It contains a first resin member to have a absorbance _{a 1} of containing a thermoplastic resin and nigrosine 0.1 to 0.5, the thermoplastic resin and the same or different thermoplastic resin from 0.01 to 0.098 And a second resin member having an absorbance a _{2 of 1} to overlap with each other to form a contact portion at their interface and/or to butt their ends to form a butted portion.
The first resin member and the second resin member are welded by irradiating the contact portion and/or the abutting portion with laser light from the first resin member side to melt the contact portion and/or the abutting portion. A method for manufacturing a laser-welded body, comprising: The method for producing a laser-welded product according to claim 13 , wherein the first resin member is melted by irradiating the laser light, and then the melt is grown toward the contact portion.