JP2018202861A - Laser welding article and manufacturing method thereof - Google Patents

Abstract

To provide: a laser welding article in which a laser beam irradiation can be performed from a side of a resin member having a laser light absorbing property in a stacked resin member, and a plurality of simply prepared resin members can be joined in a single laser welding process to integrate the same without a complicated process, and bonding strength between resin members is excellent and resin properties are not adversely affected; and a manufacturing method thereof.SOLUTION: A laser welding article 10 comprises a thermoplastic resin and a laser beam absorber, and is a material obtained by welding at least a part of a contacted part C formed by stacking a first resin member 1 that is a laser beam irradiation side resin member having absorbance aof 0.1 to 0.5, and a second resin member 2 that has absorbance aof less than 0.1 and contains a thermoplastic resin identical to or different from the thermoplastic resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser welded body in which resin members having different absorbances are integrated by laser welding, and a method for manufacturing the same.

  In recent years, lightweight thermoplastic products are often used in place of metals in vehicles such as automobiles and railways, and structural parts in the field of electronic and electrical equipment. Examples of thermoplastic resins used in these structural parts include polyester resins, polyamide resins, and polycarbonate resins. Among these, polyester resins and polyamide resins typified by polybutylene terephthalate resins and polyethylene terephthalate resins are used. Because of its excellent mechanical properties, electrical properties, heat resistance, dimensional stability, and other physical and chemical properties, it is widely used in vehicle parts, electrical / electronic equipment parts, precision equipment parts, and the like.

  Among its various applications, especially polybutylene terephthalate resin is used in products that seal electrical circuits such as automotive electrical parts (control units, etc.), various sensor parts, connector parts, etc., and polyamide resin is used, for example, as an intake manifold. It has been developed in products having a hollow part. In products that seal these electric circuits and products that have a hollow portion, it may be necessary to join a plurality of members to seal the inside. Therefore, various welding / sealing techniques such as bonding using adhesives, and bonding techniques using welding such as solvent bonding, vibration welding, ultrasonic welding, hot plate welding, injection welding, and laser welding are employed. .

  In addition to the time loss that requires a long time to cure the adhesive, the bonding with the adhesive contaminates the surroundings due to the organic solvent contained in the adhesive. In addition, joining by ultrasonic welding or hot plate welding requires post-processing due to damage to products due to vibration or heat, and generation of wear powder and burrs, thus complicating the welding process. 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 low fluidity material.

  Laser welding is performed by superimposing a laser light transmitting resin member on a laser light absorbing resin member, and the laser light irradiated from the laser light transmitting resin member side passes through the laser light absorbing resin member and is absorbed by the laser light absorbing resin member. As a result, heat is generated and both resin members are melted and welded together to be joined.

  As a feature of laser welding, it is possible to weld a resin member only by locally irradiating the laser beam to the part to be joined, and because of local heat generation, the thermal effect on the peripheral part other than the welding part Is very slight, does not generate vibration, can be welded between resin parts with minute parts and three-dimensional and complicated structures, has high reproducibility, can maintain high airtightness, For example, the strength is high, the boundary between the welded portions is not noticeable, and dust is not generated.

  According to laser welding, the resin members can be reliably welded and joined together. Further, a joining strength equal to or higher than that obtained by fastening by fastening parts (bolts, screws, clips, etc.) or by a method such as an adhesive, vibration welding, or ultrasonic welding can be obtained. In addition, laser welding can minimize the influence of heat without generating vibrations, thereby realizing labor saving, improvement in productivity, reduction in manufacturing costs, and the like. For this reason, 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 and electrical / electronic industry, and can also be used for joining resin parts with complex shapes. .

  As a technique relating to laser welding, a laser light-transmitting resin member and a laser light-absorbing resin member to which carbon black that absorbs laser light is added to Patent Document 1 are overlapped, and then laser-transmitting resin member is superposed. 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 laser light is irradiated from the laser light absorbing resin member side, the laser light is absorbed by the surface layer of the resin member, and the resin members cannot be welded together. Laser 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 is performed from the outer cylinder side of a resin component in which a laser light-transmissive resin member is arranged as an inner cylinder inserted therein Can not. Therefore, a desired resin member cannot be arranged in the resin part, and the degree of freedom in designing the resin part is narrowed.

  Laser which irradiates infrared rays from the heat-dissipating material C side by making the thermoplastic resin members A and B and the heat-dissipating material C which has an infrared permeation | transmission part contact patent document 2 so that it may become a positional relationship of C / A / B. A welding method is described. According to this method, the thermoplastic resin members A and B may be formed of the same kind of thermoplastic resin. However, this laser welding method requires a special heat-dissipating material C to adjust the heat generation during laser welding. This complicates the laser welding process.

  In Patent Document 3, joint flange portions formed in advance as welding margins between a resin member that transmits laser light and a resin member that absorbs laser light are butted together, and a joint flange portion of a resin member that transmits laser light A laser welding method is described in which laser resin is irradiated from the side and both resin members are temporarily welded together, and then the main flange is irradiated again with laser light on the joining flange portion to integrate both resin members. According to this laser welding method, the number of steps of the laser irradiation process increases the number of steps. Therefore, the process of joining the resin members by welding is prolonged, and the manufacturing cost of the resin parts is kept high.

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

  The present invention has been made to solve the above-described problems, and among the superposed resin members, laser light irradiation can be performed from the resin member side having a laser light absorption property without passing through a complicated process. Provided is a laser welded body that can be easily integrated by joining a plurality of resin members prepared in a single laser welding step, and has excellent bonding strength between resin members, and does not impair resin properties, and a method for producing the same For the purpose.

  The inventors of the present invention are a laminate in which a laser light weakly absorbable resin member having a specific absorbance that transmits while absorbing laser light and a laser transmissive resin member having an absorbance that transmits laser light are stacked. It has been found that irradiating a resin member with laser light on a laser light weakly absorbing resin member causes a wide and deep melting phenomenon at the interface between the laser light weakly absorbing resin member and the laser light transmitting resin member. . Accordingly, the inventors can obtain a laser welded body in which the resin members are joined much more firmly than the conventional laser welding in which the laser light transmitting resin member and the 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 includes a laser light irradiation side resin containing a thermoplastic resin and a laser light absorber and having an absorbance a _{1 of} 0.1 to 0.5. The first resin member, which is a member, and the second resin member containing the same or different thermoplastic resin as the thermoplastic resin and having an absorbance a _{2 of} less than 0.1 are formed by overlapping. At least a part of the contact portion is laser-welded.

Laser welding can be, for example, absorbance ratio _a 1 / _{a 2} and the absorbance _{a 1} and the absorbance _{a 2} can be mentioned those in which from 1.3 to 45.

Laser-welded article, the absorbance _{a 2} may be one which is 0.01 to 0.09.

  The laser welded body is at least a part of the contact portion formed by the end portions of the first resin members and / or the end portions of the second resin member being in contact with each other, The ends may be laser-welded. The laser light weakly absorbing resin member that is the first resin member and the laser light transmitting resin member that is the second resin member may be flat plate-like or single film-like members, and may be curved or bent. It may be a single member or a plurality of members in the form of a roll, a cylinder, a prism, or a box. In both resin members, the portions to be welded may be in contact with each other or have a gap. When both resin members are in contact, the contacted welded portion is preferably surface contact, and may be flat surfaces, curved surfaces, or a combination of flat and curved surfaces.

  In the laser welded body, the first resin member and / or the second resin member may be divided into a plurality of resin member pieces that are in contact with each other at the contact portion.

In the laser welded body, for example, the second resin member is divided into two resin member pieces, and their absorbance a _2-1 and absorbance a _2-2 are 0.05 to 0.09, absorbance _{a 1} to the absorbance ratio _a 1 _{/ a 2-1,} or absorbance ratio _a 1 _{/ a 2-2} with the absorbance _{a 1} and the absorbance _{a 2-2} with the absorbance _{a 2-1} is, 1.3 What is -45 is mentioned.

  The laser welded body preferably has a butted portion formed by the first resin member and the second resin member being butted at their end portions.

  Examples of the laser welded body include those in which the laser light absorber is nigrosine.

  In the laser welded body, the nigrosine may be a nigrosine sulfate.

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

In the laser welded body, the nigrosine may have a volume resistivity of 0.5 × 10 ^{9 to} 5.0 × 10 ¹¹ Ω · cm.

  Examples of the laser welded body include one 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.

  The laser welded body preferably has at least a part of the contacted part that is laser welded and has a fused part that spreads toward the first resin member rather than the second resin member.

  The method for producing a laser welded body of the present invention includes a first resin member containing a thermoplastic resin and nigrosine, and a thermoplastic resin of the same kind or different from the thermoplastic resin, and having a lower absorbance than the first resin member. And a second resin member having a contact portion formed on the interface between the second resin members and / or abutting portions thereof to form a butting portion, and the first resin at the contacting portion and / or the butting portion. The first resin member and the second resin member are welded by irradiating a laser beam from the member side to melt the contact portion and / or the butting portion. In particular, when nigrosine is nigrosine sulfate, it is possible to provide high-efficiency production methods because it can cope with high-speed scanning laser welding.

  The laser welded body may be produced by irradiating the laser beam to cause the first resin member to melt and then grow the melt 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 while absorbing the laser light, so that the laser light incident from the laser light weakly absorbing resin member is weakly absorbed by the laser light. As a result of reaching the contact portion that is the interface between the conductive resin member and the laser light transmitting resin member that is the second resin member that overlaps the conductive resin member, the contact portion is melted, so that it is securely and firmly welded. As described above, the laser welded body of the present invention is obtained by irradiating laser light from the laser light weakly absorbing resin member side to weld the resin members together. Further, the heat of the laser light weakly absorbing resin member generated by the incidence of the laser light at the abutting portion where the ends of the laser light weakly absorbing resin member and the laser light transmitting resin member are abutted with each other is converted into the laser light transmitting resin. As a result of conduction to the member and melting of the butt portion, the laser welded body is welded in the same manner as the welding at the contact portion.

  In addition, the laser weld weakly absorbs a laser beam that is melted by the incidence of the laser beam because the laser beam weakly absorbing resin member contains nigrosine sulfate as a laser beam absorber and exhibits higher fluidity. Since the resin member quickly flows toward the laser light transmitting resin member at the contact portion and / or the abutting portion, and melts and welds at these portions, the resin member is attached to the contact portion and / or the abutting portion. Even if voids due to surface roughness or sink marks are formed, the voids are blocked and high welding strength is expressed. It is one of the features of the present invention that it can be applied to welding members having shapes that are difficult to weld by ordinary heat conduction.

  According to the method for producing a laser welded body of the present invention, a laser beam weakly absorbable resin member is overlapped with a laser beam transmitting resin member to form a contact portion, or the end portions of both resin members are butted to meet each other. After adjusting the angle of laser light irradiation with respect to the laser light irradiated surface of the laser light weakly absorbing resin member, both resin members can be quickly attached by simply irradiating these parts with laser light. Can be welded. In particular, in the case where both superimposed resin members are welded at the contact site, laser light irradiation can be performed from the laser light weakly absorbing resin member side, so that, for example, a laser beam is applied to a structure formed of a conventional resin member. By laminating the light-absorbing resin member and irradiating with a laser, a laser welded body can be obtained later.

It is the perspective view which shows an example in the middle of manufacturing the laser welding body which applies this invention, and its AA arrow typical partial sectional drawing. It is a schematic cross section which shows the middle of manufacturing another laser welding body to which this invention is applied. It is a schematic cross section which shows the middle of manufacturing another laser welding body to which this invention is applied. It is a perspective view which shows an example in the middle of manufacturing the laser welding body to which this invention is applied. It is a perspective view which shows the middle of manufacturing another laser welding body to which this invention is applied. It is a perspective view which shows the middle of manufacturing another laser welding body to which this invention is applied. It is a schematic cross section which shows the middle of manufacturing another laser welding body to which this invention is applied. It is a cross-sectional enlarged photograph of the fusion | melting site | part of the laser weld body of Examples 1-3 and 1-4 to which this invention is applied. It is the perspective view which shows the middle of manufacturing the laser welding body of Example 5-1 and 5-2 to which this invention is applied, and its expanded partial sectional view.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, the scope of the present invention is not limited to these forms.

  FIG. 1A is a perspective view showing the course of manufacturing the laser welded body of the present invention, and FIG. The laser welded body 10 is obtained by integrating a plurality of resin members by joining them by laser welding. In the laser welded body 10, a laser light weakly absorbing resin member 1 that is a first resin member and a laser light transmissive resin member 2 that is a second resin member are overlapped, and an overlapping surface of both resin members 1 and 2 is overlapped. It welds in the contact part C which is a part of. Both resin members 1 and 2 are flat rectangular plates having a uniform thickness. Both the resin members 1 and 2 contain a thermoplastic resin, and the laser light weakly absorbable resin member 1 contains nigrosine as a laser light absorber. The laser light absorber acts as a laser light transmitting and absorbing agent by having a laser light absorption property of absorbing a part of the laser light and a laser light transmission property of transmitting the other part. To do.

  The laser beam weakly absorbing resin member 1 is a laser beam irradiated member disposed on the laser beam L irradiation side. The laser light L is irradiated substantially perpendicularly to the irradiation surface of the laser light transmissive resin member 1. The laser beam L scans in a straight line in the X direction, for example, at a speed of 0.5 to 10.0 mm / second. Accordingly, the laser welded body 10 has both the resin members 1 and 2 that are welded and integrated by solidifying after a large molten pool is formed at the contact portion C.

The laser light weakly absorbing resin member 1 has a laser light transmission and absorption property of absorbing a part of the wavelength of the incident laser light L and transmitting a part of another wavelength. The absorbance a ₁ of such a laser beam weakly absorbing resin member 1 is preferably 0.1 to 0.5, for example, for a laser beam having a wavelength range of 940 nm emitted from a semiconductor laser. It is more preferable that it is 11-0.47. When the absorbance a ₁ is within this range, the laser light weakly absorbable resin member 1 has a heat generation characteristic necessary for welding with the laser light transmissive resin member 2 and excessive heat generation due to energy concentration of the incident laser light L. It balances deterrence. As a result, the laser welded body 10 can be obtained by the irradiation operation of the laser light L from the laser light weakly absorbing resin member 1 side that absorbs the laser light.

When the absorbance a ₁ exceeds the above upper limit, the laser light weakly absorbing resin member 1 excessively absorbs the laser light L, and energy concentration occurs at the incident site of the laser light L. For this reason, the scope for selection of laser welding conditions such as laser output and scanning speed is narrowed and it becomes difficult to control the laser irradiation, so that the laser beam weakly absorbing resin member 1 is likely to be scratched, burned or voided, and the laser welded body. 10 tends to cause poor appearance. Further, the laser light weakly absorbing resin member 1 does not reach the contact site C, and the laser welded body having high welding strength cannot be obtained because the molten pool that is the melted portion melted on the incident surface side of the laser light L does not reach. . On the other hand, if the absorbance a ₁ is less than the above lower limit, even if the laser light weakly absorbing resin member 1 is irradiated with the laser light L, the amount of generated heat is insufficient, and the laser light weakly absorbing resin member 1 is laser transparent. Heat generation and melting sufficient for welding with the resin member 2 do not occur. 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. Further, since the laser beam weakly absorbing resin member 1 contains nigrosine, the crystallization temperature is lower than that of the resin member formed of the thermoplastic resin contained in the laser beam weakly absorbing resin member 1. And has improved fluidity. 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 melted by receiving the laser beam L has a high fluidity at the time of melting. For example, the contact portion C is caused by the surface roughness and sink marks of both the resin members 1 and 2. Even if a gap is formed, the weakly laser-absorbing resin member 1 melted by heat flows into the gap and closes it tightly, so that both resin members 1 and 2 are firmly welded. The melt flow rate of such a weakly laser-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 the same or different kind of thermoplastic resin as the raw material resin of the laser light weakly absorbing resin member 1. Absorbance _{a 2} of the laser ray transmitting resin member 2, for example, to a laser beam having a wavelength range of 940nm emitted from the semiconductor laser, is less than 0.1 at most, it is from 0.01 to 0.098 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. The laser light transmittance is preferably 20% or more. The absorbance a _{2 in} such a range can be obtained by the absorbance inherent in the thermoplastic resin contained as the raw material of the laser light transmissive resin member 2. On the other hand, when the absorbance of the thermoplastic resin is less than the above lower limit, a very small amount of a laser light absorbent such as nigrosine is added to the raw material composition of the laser light transmissive resin member 2, for example, 0.001 to 0.08. By including the content in mass%, the absorbance a ₂ in the above range can be imparted to the laser light transmitting resin member 2. When the included nigrosine absorbs the laser light, the laser light transmitting resin member 2 generates heat at a temperature lower than the heat generated by the laser light weakly absorbing resin member 1, and a residual heat effect is generated. Thereby, it is possible to perform laser welding with a small temperature difference between the 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.

  In addition, when both the resin members 1 and 2 are the same color tone or the same color tone, the interface and the welding trace are not conspicuous, and the laser welded body 10 which is rich in design property can be obtained. The color tone is preferably dark, and particularly preferably black. 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 the thermoplastic resin that 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 includes, for example, the following processes A to D.

Step A: Laser light weakly absorbable resin composition for forming the laser light weakly absorbable resin member 1 which contains a thermoplastic resin and a laser light absorbent and may contain a colorant and additives as necessary. Prepare the product. The content of the laser light absorber is adjusted based on the absorbance inherent in 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 weakly laser-absorbing resin member 1 is molded.

Step B: A laser light transmitting resin composition containing a thermoplastic resin of the same type or different from the thermoplastic resin contained in the laser light weakly absorbing resin composition is prepared. When the thermoplastic resin has a remarkably low absorbance, a laser light absorbent and / or a colorant is added to the laser light transmissive resin composition as necessary, and the absorbance a ₂ is 0.1 above. Or less, specifically 0.01 to 0.098, and further may be adjusted to fall within the range of 0.01 to 0.09. In this way, a laser light transmissive resin composition for molding the laser light transmissive resin member 2 that generates heat to such an extent that it can be welded at the contact site C by the incidence of the laser light L can be prepared. Next, for example, a rectangular plate-shaped laser light transmitting resin member 2 is molded using a molding machine.

  Step C: The laser beam weakly absorbing resin member 1 and the laser beam transmissive resin member 2 are overlapped to form the contact portion C. At this time, both the resin members 1 and 2 may be clamped and fixed by pressing. Furthermore, a member having an antireflection function such as a glass plate or an antireflection film on the surface of the laser beam weakly absorbing resin member 1 on the incident side of the laser beam L, or shielding or attenuating the laser beam within a desired range. A transparent member such as a glass plate that does not work may be disposed.

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

The heat of the molten pool is radiated and conducted to the interface between the laser beam weakly absorbing resin member 1 and the laser beam transmitting resin member 2. On the other hand, since the laser light transmitting resin member 2 has the absorbance a ₂ , the laser light transmitting resin member 2 does not transmit all of the laser light L transmitted through the laser light weakly absorbing resin member 1 but absorbs it very slightly. The laser light transmitting resin member 2 generates heat at the contact portion C and melts due to the heat conduction in the molten pool and the slight absorption of the laser light L. As a result, the molten pool grows so as to expand 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, the molten absorbance a ₁ laser light weakly-absorbing resin member 1 is due to greater than the absorbance a ₂ of the laser ray transmitting resin member 2, it is formed by a laser beam weakly absorbing resin member 1 side The pool has a volume larger than that of the laser light transmitting resin member 2 side. In particular, when both the resin members 1 and 2 are placed on the work table so that the contact part C is positioned substantially horizontally, the molten pool generated by the weakly laser-absorbing resin member 1 is transparent to laser light by gravity. It tends to grow toward the resin member 2. In this case, the molten pool can be grown in a wider range of the contact portion C. The molten pool is cooled, and the thermoplastic resin contained in both resin members 1 and 2 is solidified. As a result, a fusion part having a substantially elliptical cross section extending over the laser light transmitting resin member 2 is formed at the contact part C while spreading toward the laser light weakly absorbing resin member 1 side. As a result, the resin members 1 and 2 are firmly joined at the welded contact portion C, and the laser welded body 10 is completed.

  In step D, a cooling process of blowing air or an inert gas at a low temperature or room temperature may be performed on the surface on the incident side of the laser beam L. Moreover, when both the resin members 1 and 2 generate | occur | produce gas at the time of laser welding, you may process this using a gas processing apparatus. Thereby, laser burn (burning) of the laser light irradiated surface can be prevented.

FIG. 2 (a) shows a schematic cross-sectional view showing the way in which another laser welded body 10 is being manufactured. The laser beam weakly absorbing resin member 1 disposed on the irradiation side of the laser beam L is welded to the laser beam transmitting resin member 2 overlapping with the laser beam transmitting resin member 2 at the contact site C. On the other hand, the laser light transmissive resin member 2 has two divided laser light transmissive resin member pieces 2a and 2b. The absorbance a _{2-1 of} the laser light transmissive resin member piece 2a and the absorbance a _2-2 of the laser light transmissive resin member piece 2b are, for example, for laser light having a wavelength range of 940 nm emitted from a semiconductor laser. It is preferably 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 still more preferable that it is 0.07-0.09. The absorbance a _2-1 and the absorbance a _2-2 may be the same as or different from each other as long as they are within this value range. Further, the absorbance ratio a ₁ / a _2-1 between the absorbance a ₁ and the absorbance a _2-1 of the laser beam weakly absorbing resin member 1 is preferably 1.3 to 45, and is 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 as or different from each other within the range of this value.

  The laser light transmitting resin member pieces 2a and 2b are welded at a contact portion N adjacent to each other and contacting the ends. The laser beam L is irradiated immediately above the contact part N. As a result, 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 part C and the contact part N.

  FIG. 2B is a schematic cross-sectional view showing the middle of manufacturing another laser welded body 10. The laser beam weakly absorbing resin member 1 and the laser beam transmitting resin member 2 are overlapped to form a contact portion C. The laser beam weakly absorbable resin member 1 is divided into two laser beam weakly absorbable resin member pieces 1a and 1b, which are adjacent to each other and in contact with each other. Thereby, the contact part N is formed. The laser beam L is irradiated to the contact part N from the laser beam weakly absorbing resin member 1 side, whereby the laser beam weakly absorbing resin member pieces 1a and 1b and the laser beam transmitting resin member 2 are in contact with each other. They are welded and integrated at the part C and the contact part N.

FIG. 2 (c) is a schematic cross-sectional view showing the way in which another laser welded body 10 is being manufactured. 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. , Each has. Both joint portions 1c and 2c are stepped with the same height. Since the step shape of both splice portions 1c and 2c are opposed to each other and are alternately combined, contact portion C where both resin members 1 and 2 are overlapped, and upper abutting portion B where the end portions are butted together ₁ and site B ₂ abutting the lower side. In the contact portion C, the first joint portion 1c is disposed on the incident side of the laser light L. The laser beam L is irradiated from the first joint portion 1c side, whereby the laser beam weakly absorbing resin member 1 and the laser beam transmitting resin member 2 are welded and integrated at the contact portion C.

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

FIG. 2 (d) is a schematic cross-sectional view showing the way in which another laser welded body 10 is being manufactured. The laser beam weakly absorbing resin member 1 and the laser beam transmitting resin member 2 are overlapped to form a contact portion C. The laser light weakly absorbable resin member 1 is divided into two parts, and the laser light weakly absorbable resin member pieces 1a and 1b are divided into two parts. The laser light transmissive resin member 2 is also divided into two parts and laser light transmissive resin member pieces 2a and 2b are divided into two parts. Each has. Accordingly, the first contact portion N ₁ where the ends of the laser light weakly absorbing resin member pieces 1a, 1b are in contact with each other, and the second contact where the ends of the laser light transmissive resin member pieces 2a, 2b are in contact with each other. contact site N ₂ are respectively formed. The first contact portion N ₁ is a laser-transmissible resin piece 2a, the second contact portion N ₂ is a laser beam weakly absorbing resin piece 1b, respectively overlap. That is, the first contact portion N ₁ and the second contact portion N _2, are formed offset so as not to overlap each other.

On the other hand, the laser light L is along the X direction (see FIG. 1 (a) / depth direction in FIG. 2 (d)) on the surface of the laser light weakly absorbing resin member piece 1b, and the Y direction perpendicular thereto. Scanning is also performed (in the horizontal direction in FIG. 2D). Thereby, in addition to the two resin members 1 and 2 being welded in a wide range of the contact portion C, the both contact portions N ₁ and N ₂ are also welded. Furthermore, by each abutment portion N _1, N ₂ are displaced, the first contact portion N ₁ is the laser-transmissible resin piece 2a, the second contact portion N ₂ laser beam weakly absorbing resin Each member 1b is supported. As shown there, the resin members 1 and 2 are formed by the contact portion C welded over a wide range and the contact portions N ₁ and N ₂ welded while being supported by the resin member pieces 1b and 2a, respectively. It is welded to strength. As a result, even if this laser welded body 10 receives an external force such as bending or twisting, it is difficult for the laser welded body 10 to peel off at the welded site.

  Since both the resin members 1 and 2 are formed in 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 light transmissive resin member 2 may be formed in a cylindrical shape having both ends opened as shown in FIG. 3A, and all are folded in a plurality of places as shown in FIG. Or you may have the contact | abutting site | part N which is bent or formed by valley fold and making it contact while abutting the edge parts. Even if the laser light transmitting resin member 2 has such a shape, the laser light weakly absorbing resin member 1 is arranged on the irradiation side of the laser light L and irradiated with the laser light L, Obtaining the laser welded body 10 in which the resin members 1 and 2 are welded at the contact part C of the resin members 1 and 2 and / or the contact part N where the ends of the laser light transmitting resin member 2 are abutted with each other. Can do.

  As shown in FIG. 4, by laminating the label 4 as the laser light weakly absorbing resin member on the existing transparent resin bottle 3 as the laser light transmissive resin member, and irradiating the laser light L from the label 4, You may weld both in the contact site | part of the curved trunk | drum of the resin bottle 3, and the label 4. FIG. According to this, the laser welded body 10 can be obtained later using the resin bottle 3 as necessary.

  Further, as shown in FIG. 5 (a), the end portions 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, thereby weakly absorbing laser light. After the contact portion is formed by covering the contact portion with the belt-like member 6 which is a resin member, the laser beam L may be irradiated while being scanned along the belt-like member 6 as shown in FIG. According to this, the cylindrical members 5a and 5b and the belt-like member 6 are welded at the contact part N and the contact part C, and the laser welded body 10 obtained by joining the cylindrical members 5a and 5b is obtained.

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

  The laser light weakly absorbable resin member 1 and the laser light transmissive resin member 2 are incident on the laser light irradiated surface of the laser light weakly absorbable resin member 1 obliquely toward the abutting portion formed by abutting each other. The laser weld L may be produced by irradiating the laser beam L. 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 as to have the same inclination angle, and the inclined end faces are abutted to meet each other. May be formed. In this case, it is preferable that the irradiation angle of the laser light L is an angle at which the laser light L is irradiated substantially perpendicularly to the inclined end surface. Thereby, even if the butt | matching site | part B inclines, the welding site | part over the wide range of the butt | matching site | part B is formed, and the laser weld body 10 to which both the resin members 1 and 2 were joined firmly is obtained.

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

  In the case of using a halogen lamp that generates infrared rays having a wavelength of 700 nm or more, examples of the lamp shape include those in which the lamps are arranged in a band shape. As an irradiation mode, for example, a scanning type capable of irradiating a laser beam over a wide range by moving a lamp irradiation unit, a masking type in which a member to be welded moves, and a resin member to be welded in various directions The type that simultaneously irradiates the lamp. 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 on the short wavelength side of the energy distribution, that is, in the visible region. In such a case, welding marks may be formed on the surface of the incident member. Therefore, for example, the energy in the visible region may be blocked using a cut filter.

  It is preferable that the thickness of both the resin members 1 and 2 is 200-5000 micrometers. When the thickness is less than 200 μm, it is difficult to control the laser beam energy, and during laser welding, excessive and insufficient thermal melting may occur, resulting in fracture due to overheating or insufficient bonding strength due to insufficient heat. On the other hand, when the thickness exceeds 5000 μm, since the distance to the site to be welded is long, the laser light incident on the laser light weakly absorbing resin member 1 is attenuated without being transmitted to the inside thereof, Sufficient bonding strength cannot be obtained.

Nigrosine was cited as the laser light absorber contained in both resin members 1 and 2, but in addition, nigrosine salt, azine compound, aniline black, phthalocyanine, naphthalocyanine, porphyrin, cyanine compound, perylene, quaterylene, Examples include azo metal complexes, near-infrared absorbing anthraquinones, squaric acid, and immonium dyes. The salt of nigrosine is preferably nigrosine sulfate. The absorption coefficient ε _d (ml / g · cm) of the laser light absorber that may be used alone or in combination of a plurality of types is 1000 to 8000, preferably 1000 to 6000. Preferably it is 3000-6000 (ml / g * cm).

The method for measuring the absorption coefficient (absorption coefficient) ε _d is as follows: 0.05 g of a laser beam absorbent is precisely weighed and dissolved in, for example, a solvent N, N-dimethylformamide (DMF) using a 50 ml volumetric flask. Is diluted with DMF using a 50 ml volumetric flask to obtain a measurement sample, and absorbance measurement is performed using a spectrophotometer (trade name: UV1600PC, manufactured by Shimadzu Corporation).

  The thermoplastic resin is colored for the purpose of decorating effects, color-coding effects, improving the light resistance of molded products, and protecting or concealing 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. Among these, nigrosine, which can be used as a black colorant or a laser light absorber and can obtain higher bonding strength, is preferable.

  As nigrosine, C.I. I. Solvent Black 5 and C.I. I. Examples thereof include black azine-based condensation mixtures such as those described in the Color Index as Solvent Black 7. Such nigrosine can be synthesized, for example, by oxidation and dehydration condensation of aniline, aniline hydrochloride and nitrobenzene at a reaction temperature of 160 to 180 ° C. in the presence of iron chloride. 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 been subjected to a purification step of removing impurities from the inorganic salt can be suitably used because it does not deteriorate the physical properties of the resin composition that is the raw material of both resin members 1 and 2. In addition, a material containing nigrosine, which exhibits a high volume resistivity, can be suitably used for parts that require high insulation, such as parts for electrical and electronic equipment and precision equipment. Can be widely applied. In addition, the volume resistivity of nigrosine is obtained as follows. A sample of a certain amount of nigrosine is solidified by applying a load of 200 kgf, and the volume of this sample is determined. The sample is then measured with a digital ultrahigh resistance / microammeter (trade name: 8340A, manufactured by ADC Corporation).

  Nigrosine is preferably sulfate. Nigrosine sulfate functions as a fluidity improver, a surface gloss enhancer, and a crystallization temperature lowering agent, and therefore improves the fluidity of the resin composition during laser welding.

  According to the nigrosine production reaction system using iron chloride as a catalyst, nigrosine hydrochloride is produced because the reaction is carried out in the presence of iron chloride or excess hydrochloric acid. 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 is replaced with sulfate ions, and a known reaction method is used. obtain. Nigrosine sulfate is a C.I. I. An oil-soluble black dye belonging to Solvent black 5, C.I. I. It is not a water-soluble black dye belonging to Acid Black 2.

  In order to produce nigrosine sulfate, specifically, for example, a method of dispersing nigrosine in dilute sulfuric acid and appropriately heating (for example, 50 to 90 ° C.) can be mentioned. Further, for example, it is produced by dispersing a condensation reaction solution obtained by producing nigrosine in dilute sulfuric acid and heating it appropriately (for example, 50 to 90 ° C.). Furthermore, for example, nigrosine sulfate can be produced by adding nigrosine dissolved in concentrated sulfuric acid to a large amount of ice water while precipitating crystals while adjusting the reaction liquid temperature to a low level so that sulfonation does not occur. .

  In nigrosine sulfate, since the sulfate ion concentration is 0.3 to 5% by mass, preferably 0.5 to 3.5% by mass, the effect of lowering the crystallization temperature of the thermoplastic resin is increased. Laser welding can be performed stably.

  As such nigrosine, the product name: NUbian BLACK series manufactured by Orient Chemical Industry Co., Ltd. is commercially available.

The content of the laser light absorber such as nigrosine for adjusting the absorbance a ₁ is 0.001 to 0.5% by mass in the laser light weakly absorbing resin member 1, preferably 0.001 to 0.4. % By mass. For example, when a polyamide resin is used as the thermoplastic resin for the laser light weakly absorbing resin member 1, the content of the laser light absorbent is 0.01 to 0.2% by mass in the laser light weakly absorbing resin member 1. It is preferable that it is 0.01-0.15 mass%. When the content is less than 0.01 wt%, the absorbance a ₁ is less than the lower limit of the above. Therefore, the laser beam weakly absorbing resin member 1 that absorbs a part of the energy of the laser beam has an excessively small amount of heat generation, so that it does not sufficiently raise the temperature, and the contact part C, butting part B, and contact part N As a result, the bonding strength between the resin members 1 and 2 is insufficient. Further, when the content exceeds 0.2 mass%, the absorbance a ₁ exceeds the upper limit of the above. Therefore, the laser light transmittance is excessively lowered, and only the resin member on the laser light incident side such as the laser light weakly absorbing resin member 1 generates excessive energy absorption and generates heat and melts. , 2 cannot be welded uniformly, and high bonding strength cannot be obtained. Furthermore, if the resin member disposed on the laser beam incident side absorbs excessive energy of the laser beam, the resin characteristics such as physical and chemical characteristics of the thermoplastic resin as the raw material thereof are easily lost.

On the other hand, as the absorbance a ₂ , the absorbance inherent in the thermoplastic resin contained in the laser light transmitting resin member 2 can be used as it is. In this case, the laser light transmitting resin member 2 may not contain a laser light absorber or a colorant. In this case the absorbance of the thermoplastic resin is less than the lower limit value of the absorbance a _2, the absorbance a ₂ by adding a small amount of laser light absorbing agent to the thermoplastic resin can be kept within the range of the above values.

  The thermoplastic resin contained in both the 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 types of monomers forming the same are bonded. 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 Examples include polymer resins, PC-PBT copolymer resins, and PC-PA copolymer resins. Also, 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 based on these resins can be mentioned. In addition, the molecular weight of these thermoplastic resins is not specifically limited. Moreover, you may use these thermoplastic resins individually or in mixture of multiple types.

  The thermoplastic resin is preferably a polyamide resin, a polycarbonate resin, a polypropylene resin, a polybutylene terephthalate resin, or a polyphenylene sulfide resin. Of these, polyamide resins and polycarbonate resins are more preferred from the viewpoint of good compatibility with a laser light absorber such as nigrosine.

  The polyamide resin in the present invention is a polyamide polymer having an acid amide group (—CONH—) in the molecule and capable of being melted by heating. Preferably, the polyamide resin includes 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 the structural 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 a lactam polycondensate, a polycondensate of diamine and dicarboxylic acid, a polycondensate of ω-aminocarboxylic acid, or a copolymerized polyamide resin or blend thereof. Can be mentioned. Examples of the lactam that is a raw material for polycondensation of polyamide resin include ω-laurolactam, enantolactam, capryllactam, lauryllactam, α-pyrrolidone, α-piperidone, and ω-laurolactam.

  Examples of the diamine include tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, octamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2-methylpentamethylene diamine, (2,2,4- or 2,4,4 -) Aliphatic diamines such as trimethylhexamethylenediamine, nonamethylenediamine, 5-methylnonamethylenediamine; 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, 2-bis Alicyclic diamines such as 4-aminocyclohexyl) propane, bis (aminomethyl) decalin, bis (aminomethyl) tricyclodecane, bis (aminopropyl) piperazine, and aminoethylpiperazine; metaxylylenediamine (MXDA), Examples include aromatic diamines such as paraxylylenediamine, paraphenylenediamine, bis (4-aminophenyl) ether, and bis (aminomethyl) naphthalene.

  Examples of the dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, glutaric acid, pimelic acid, undecanedioic acid, dodecanedioic acid, hexadecadionic acid, hexadecenedionic acid, eicosandioic acid, dichoic 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-methylterephthalic acid Examples thereof include aromatic dicarboxylic acids such as acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, and xylylene dicarboxylic acid.

  Examples of ω-aminocarboxylic acid include 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, paraaminomethylbenzoic acid, 2-chloro-paraaminomethylbenzoic acid, and 2-methyl-paraaminomethylbenzoic acid. Is mentioned.

  As polyamide resins, 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 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 / non-crystalline polyamide copolymer. A polymer is mentioned. 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 / polyesters. Examples include acrylic ester mixed polymers and polyamide / silicone mixed polymers. You may use these polyamide resins individually or in mixture of multiple types.

  The polyphenylene sulfide (PPS) resin is a polymer mainly composed of 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 under high temperature and high pressure. There are two types of PPS resins: a linear type that has a desired degree of polymerization only by a polymerization step using a polymerization aid, and a crosslinked type that is obtained by thermally crosslinking a low molecular weight polymer in the presence of oxygen. Roughly classified. In particular, a linear PPS resin is preferable because of its excellent laser light transmittance. Further, the melt viscosity of the PPS resin is not particularly limited as long as melt kneading is possible, but usually 5 to 2000 Pa.s. The range is preferably s, and more preferably 100 to 600 Pa · s.

  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. System alloys. Since 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 between terephthalic acid and ethylene glycol, and a polybutylene terephthalate resin obtained by a polycondensation reaction between terephthalic acid and butylene glycol. Examples of other polyester resins 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 a glycol component such as butylene glycol, such as terephthalic acid component or glycol, such as 15 mol% or less (for example, 0.5 to 15 mol%), preferably 5 mol% or less (for example, 0.5 to 5 mol%). Examples include a copolymer in which a part of the component 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 multiple types.

  Specifically, an aromatic dicarboxylic acid or an ester-forming derivative thereof is preferably used as the dicarboxylic acid compound constituting the polyester resin. 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, diphenyl ether-4,4′-dicarboxylic acid, diphenylmethane-4,4′-dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid, Diphenylisopropylidene-4,4′-dicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4′-dicarboxylic acid, anthracene-2,5-dicarboxylic acid, anthracene-2,6-dicarboxylic acid, p- Terphenylene-4,4′-dicarboxylic acid and pyridine-2,5-dicarboxylic acid And the like, the terephthalic acid can be preferably used. These aromatic dicarboxylic acids may be used as a mixture of two or more. As is well known, these compounds can be used in polycondensation reactions with dimethyl esters or the like as ester-forming derivatives in addition to free acids. In addition, if it is a small amount, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, dodecanedioic acid, and sebacic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid as well as these aromatic dicarboxylic acids. One or more alicyclic dicarboxylic acids such as acid and 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 dihydroxy compounds constituting the polyester resin , Alicyclic diols such as cyclohexane-1,4-dimethanol, 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, and polytetramethylene glycol may be copolymerized. In addition, 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 bifunctional monomers, trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane are introduced to introduce a branched structure, and fatty acids are used for molecular weight adjustment. A small amount of a monofunctional compound such as can be used in combination.

  As the polyester resin, those mainly containing polycondensation of dicarboxylic acid and diol, that is, those containing 50% by mass, preferably 70% by mass or more of the total resin, of this polycondensate are used. An aromatic carboxylic acid is preferred as the dicarboxylic acid, and an aliphatic diol is preferred as the diol. More preferred is polyalkylene terephthalate in which 95 mol% or more of the acid component is terephthalic acid and 95 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 1,4-butanediol or ethylene glycol component. As the polyester resin, the main component is preferably polybutylene terephthalate. The polybutylene terephthalate may be a copolymer such as isophthalic acid, dimer acid, and polyalkylene glycol such as polytetramethylene glycol (PTMG).

  Examples of polyolefin resins 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 copolymers with other copolymerizable unsaturated monomers (Examples of copolymers include block copolymers, random copolymers, and graft copolymers). 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 admixture of plural kinds. 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.

  In addition, as polyolefin resin, you may use what contained the foaming agent in resin itself like the acid modified polyolefin modified with unsaturated carboxylic acid or its derivative (s), and a foamed polypropylene. Further, ethylene-α-olefin copolymer rubber, ethylene-α-olefin-nonconjugated diene compound copolymer (for example, EPDM), ethylene-aromatic monovinyl compound-conjugated diene compound copolymer rubber, and these Hydrogenated rubbers may contain a polyolefin resin.

  The polycarbonate resin is a thermoplastic resin having a carbonate ester bond in the main chain, and is an engineer plastic having excellent mechanical properties, heat resistance, cold resistance, electrical properties, and transparency. Currently, the industrially mass-produced polycarbonate resin is an aromatic polycarbonate obtained from bisphenol A. Examples of the production method include a phosgene method and a transesterification method. The chemical structural formula of the polycarbonate resin has a bulky benzene nucleus and a flexible carbonate in the molecular main chain in a linear molecule in which many carbonates of aromatic hydrocarbons are linked. The former gives a high heat distortion temperature and excellent physical and mechanical properties, while the latter contributes to moldability and flexibility, but is easily hydrolyzed with alkali.

Since the laser light weakly absorbing resin member 1 contains a laser light absorber such as nigrosine which is a black colorant, it exhibits a gray to black color tone depending on its content. However, since the content of the laser light absorber is determined so as to show an absorbance a _{1 of} 0.1 to 0.5, the color density of the laser light weakly absorbing resin member 1 is not sufficient, for example, gray May have a pale color. In such a case, in order to impart a desired color density to the laser beam weakly absorbing resin member 1, a colorant may be added to the laser beam weakly absorbing resin composition for molding the laser beam weakly absorbing resin member 1. A colorant can also be added to the laser light transmissive resin composition for forming the laser light transmissive resin member 2. Thereby, for example, the same color can be given to both the resin members 1 and 2, and the interface and welding trace between them can be made inconspicuous.

  The colorant is selected according to the hue and color density of the thermoplastic resin contained in the resin composition. For example, when dark black is applied 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 coloration Like a combination with an agent, a black colorant can be prepared by combining a plurality of colorants.

  Such a colorant is preferably a combination of a plurality of dyes that absorbs the visible region, is highly compatible with a thermoplastic resin, and has low scattering characteristics with respect to laser light. Furthermore, the colorant is resistant to fading even when exposed to high temperatures during molding of both resin members 1 and 2 and when melted by laser light irradiation, has excellent heat resistance, and has a wavelength in the near infrared region of the laser light. It is more preferable that the material has no absorbability.

  Specific examples of such colorants include azomethine, anthraquinone, quinacridone, dioxazine, diketopyrrolopyrrole, anthrapyridone, isoindolinone, indanthrone, perinone, perylene, indigo. , Organic dyes of thioindigo, quinophthalone, quinoline, and triphenylmethane. A colorant containing at least an anthraquinone dye having transparency to laser light used for laser welding is preferred.

  Such an anthraquinone dye is preferably an anthraquinone oil-soluble dye. 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; I. Solvent Green 3, 19, 20, 23, 24, 25, 26, 28, 33, and 65; C.I. I. 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 are commercially available Dyes.

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

  In addition, it is preferable that the anthraquinone dye 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 trade names, manufactured by Orient Chemical Industry Co., Ltd.). .

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

  This electrical conductivity is measured as follows. Disperse 5 g of the 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 previously measured weight, and the electric conductivity of this solution is measured with an electric conductivity meter (product name: AOL-10, manufactured by Toa DKK Corporation).

  Examples of combinations of dyes include combinations of anthraquinone blue dyes with other blue dyes, red dyes, and yellow dyes, and combinations of anthraquinone blue dyes with green dyes, red dyes, and yellow dyes. Examples of the 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. Examples of the dye that imparts good color developability to both the resin composition of the laser light weakly absorbing resin composition and the laser light transmitting resin composition include perinone dyes and red or yellow anthraquinone dyes.

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

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

  As an anthraquinone red dye (including an anthrapyridone dye), for example, C.I. I. Solvent Red 52, 111, 149, 150, 151, 168, 191, 207, and 227; I. Disperse Red 60 is an example. Such perinone dyes and anthraquinone red dyes are commercially available with the above color index.

  As a dye used in combination with such an anthraquinone red dye, an anthraquinone yellow dye is suitable. 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 yellow dyes 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. Examples include dyes that are commercially available with Vat Yellow 1, 2, and 3 color indexes.

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

  Specific examples of the anthraquinone acidic dye used for the salt-forming dye 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; C.I. I. Acid Green 37; C.I. I. Acid Violet 36, 41, 43, 51, and 63 are anthraquinone dyes having a sulfonic acid group in one molecule.

  As anthraquinone acidic dye, in addition to the above, specifically, for example, 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. Examples include anthraquinone dyes that are commercially available with a color index of Acid Violet 34 and 42 and have two sulfonic acid groups in one molecule of anthraquinone.

  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, the anthraquinone skeleton preferably has a structure in which a substituent having a sulfonic acid group is bonded to an anilino group as at least one substituent.

  Suitable anthraquinone salt-forming dyes include anthraquinone salt-forming dyes having an anilino group derivative as a substituent. Such anthraquinone salt-forming dyes are highly compatible with aromatic thermoplastic resins and can impart high heat resistance.

Such a preferred anthraquinone dye has 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 organic Ammonium ion, a and b are 1 to 2 positive numbers, m and n are 1 to 2 positive numbers, 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 each 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, and 1 to 18 carbon atoms. It is a linear or branched alkoxy group or a halogen atom).

  In the chemical formulas (1) and (2), specific examples of the linear or branched alkyl group having 1 to 18 carbon atoms include, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an 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. Moreover, as a C1-C18 linear or branched C1-C18 alkoxy group, specifically, for example, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an 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 Is mentioned. 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, at the time of molding of each resin member 1, 2, 3 or laser welding, it is possible to suppress their thermal deterioration due to thermal melting. Specific examples of the anthraquinone acidic dye having two phenylamino derivatives as substituents in one molecule as 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.

  Specific examples of amines that can be suitably used for the salt-forming dye represented by the chemical formula (1) include hexylamine, pentylamine, octylamine, 2-ethylhexylamine, di- (2-ethylhexyl) amine, and dodecylamine. Aliphatic monoamines such as; alicyclic amines such as cyclohexylamine, dicyclohexylamine, and dihydroadiethylamine; tetramethylenediamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine, dodecamethylenediamine, 2-methylpenta Aliphatic, alicyclic, aromatic such as methylenediamine, 2-methyloctamethylenediamine, trimethylhexamethylenediamine, bis (p-aminocyclohexyl) methane, m-xylenediamine, and p-xylenediamine Diamines; alkoxyalkylamines such as 3-propoxypropylamine, di- (3-ethoxypropyl) amine, 3-butoxypropylamine, octoxypropylamine, and 3- (2-ethylhexyloxy) propylamine; α-naphthylamine , Β-naphthylamine, 1,2-naphthylenediamine, 1,5-naphthylenediamine, and aromatic amines such as 1,8-naphthylenediamine; aromatic alkylamines such as 1-naphthylmethylamine; N Alkanol group-containing amines such as cyclohexylethanolamine, N-dodecylethanolamine, and N-dodecylimino-diethanol; such as 1,3-diphenylguanidine, 1-o-tolylguanidine, and di-o-tolylguanidine Guanidine derivatives It is.

Commercially available quaternary ammonium may be used as the amines. As such quaternary ammonium, specifically, for example, Cotamine 24P, Cotamine 86P Conch, Cotamine 60W, Cotamine 86W, Cotamine D86P (distearyldimethylammonium chloride), Sanizol C, and Sanizol 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, Inc., ARCARD is a trade name); PRIMENE MD amine (methanediamine), primin 81-R (highly branched tert-alkyl (C ₁₂ -C ₁₄₎ primary amine isomer mixture), Puraimin TOA amine (tert- octylamine), Puraimin RB-3 (tert- alkyl primary amine mixture), and Puraimin JM-T amine (high branched tert- alkyl ( C ₁₆ -C ₂₂ ) primary amine isomer mixture) (above, manufactured by Dow Chemical Co., Ltd., PRIMENE is a registered trademark).

  Content of a coloring agent is 0.01-3 mass parts with respect to 100 mass parts of thermoplastic resins, Preferably it is 0.05-1.0 mass part, More preferably, it is 0.1-0.8 mass part. It is. By adjusting the content of the colorant to such a range, it is possible to obtain a highly color-developing laser light-absorbing resin composition and a laser light-transmitting resin composition.

  When preparing these resin compositions, it is preferable to prepare a masterbatch containing a colorant and add the 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 master batch is preferably 5 to 90% by mass, and more preferably 20 to 60% by mass.

  The laser light transmitting resin composition does not contain a laser light absorber, or the content thereof is small, so that the laser light transmitting resin member 2 is not only achromatic, but also a chromatic colored member. can do. For example, the laser light transmitting resin member 2 can be colored yellow, red, blue, green, and purple using the colorant exemplified above.

  If necessary, these resin compositions may be blended with various additives in the thermoplastic resin raw material in addition to the colorant. Examples of such additives include reinforcing materials, fillers, ultraviolet absorbers or light stabilizers, antioxidants, antibacterial / antifungal agents, flame retardants, colorants, dispersants, stabilizers, plasticizers, Examples include modifiers, antistatic agents, lubricants, mold release agents, crystal accelerators, and crystal nucleating agents. Further examples include white pigments and organic white pigments such as titanium oxide, zinc sulfate, zinc white (zinc oxide), calcium carbonate, and alumina white. According to this, an achromatic thermoplastic material can be adjusted to a chromatic color in combination with an organic dye / 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 rock wool, and aramid, polyphenylene sulfide resin, polyamide, polyester, and liquid crystal polymer Organic fibers such as For example, when imparting transparency to a resin member, glass fibers can be suitably used for reinforcement thereof. Such a glass fiber has a fiber length of 2 to 15 mm and a fiber diameter of 1 to 20 μm. There is no restriction | limiting in particular about the form of glass fiber, For example, roving and a milled fiber are mentioned. These glass fibers may be used individually by 1 type, or may be used in combination of 2 or more type. The content is preferably 5 to 120 parts by mass with respect to 100 parts by mass of the laser light transmitting resin member 1, for example. If it is less than 5 parts by mass, a sufficient glass fiber reinforcing effect cannot be obtained, and if it exceeds 120 parts by mass, the moldability is lowered. Preferably it is 10-60 mass parts, Most preferably, it is 20-50 mass parts.

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

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

  As antioxidants, phenolic compounds having phenolic hydroxyl groups, triphenyl phosphite, diphenyl decyl phosphite, phenyl diisodecyl phosphite, tri (nonylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) ) Phosphorus compounds having a phosphorus atom such as pentaerythritol diphosphite and bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, didodecylthiodipropionate, ditetra Decylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol tetrakis (3-dodecylthiopropionate), thiobis (N-phenyl-β-naphthylamine), 2-mercaptobenzothiazole, 2-mer Script benzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate, nickel isopropyl xanthate, and sulfur-based compounds and thioether-based compound having a trilauryl trithiophosphite etc. sulfur atom.

  As antibacterial and antifungal agents, 2- (4′-thiazolyl) benzimidazole, 10,10′-oxybisphenoxyarsine, N- (fluorodichloromethylthio) phthalimide, and bis (2-pyridylthio-1-oxide) zinc 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, 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 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, phosphate ester, polyphosphoric acid, ammonium polyphosphate, red phosphorus, phenoxyphosphazene having a bond between a phosphorus atom and a nitrogen atom in the main chain, and aminophosphazene. Of the phosphazene compound. 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 compound, and boron compound.

  The plasticizer is not particularly limited, and examples thereof include phthalate esters (for example, dimethyl phthalate, butylbenzyl phthalate, and diisodecyl phthalate), phosphate esters (for example, tricresyl phosphate, and 2-ethylhexyl diphenyl phosphate), sulfone Amide plasticizers (for example, n-butylbenzenesulfonamide, p-toluenesulfonamide, etc.) can be mentioned. Further, polyester plasticizer, polyhydric alcohol ester plasticizer, polycarboxylic acid ester plasticizer, bisphenol plasticizer, amide plasticizer, ester plasticizer, amide ester plasticizer, glycerin plasticizer, In addition, an epoxy plasticizer (for example, an epoxy triglyceride composed of an epoxy alkyl stearate and soybean oil) can be used.

  Any impact resistance improving agent can be used as long as it has the effect of improving the impact resistance of the resin. Examples include known materials such as polyamide elastomers, polyester elastomers, styrene elastomers, polyolefin elastomers, acrylic elastomers, polyurethane elastomers, fluorine elastomers, silicone elastomers, and acrylic core / shell elastomers. It is done. Of these, polyester elastomers and styrene elastomers are preferable.

  You may manufacture both the resin members 1 and 2 using the masterbatch of a desired colored thermoplastic resin composition. Such a master batch can be obtained by any method. For example, resin powder and / or pellets that are the base of a masterbatch and a colorant are mixed with a mixer such as a tumbler or super mixer, and then heated and melted with an extruder, batch kneader, or roll kneader. And can be obtained by pelletizing or coarsening.

  The molding of both the resin members 1 and 2 can be performed by various commonly performed procedures. For example, the colored pellets can be used for molding by a processing machine such as an extruder, an injection molding machine, and a roll mill. In addition, transparent thermoplastic resin pellets and / or powder, pulverized colorant, and various additives as necessary are mixed in an appropriate mixer, and the resulting resin composition is processed into a processing machine. You may shape | mold using. Further, for example, a colorant may be added to a monomer containing an appropriate polymerization catalyst, a desired resin may be synthesized by polymerizing this mixture, and this may be molded by an appropriate method. As a molding method, for example, molding methods such as injection molding, extrusion molding, compression molding, foam molding, blow molding, vacuum molding, injection blow molding, rotational molding, calendar molding, and solution casting can be employed. By such molding, both resin members 1 and 2 having various shapes can be obtained.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to these Examples.

(Preparation of laser light transmissive 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) = The powder was mixed at 5: 3: 2 (mass ratio) to obtain Colorant A.
[Colorant B] Salt 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) was mixed with powder to obtain Colorant B.
[Colorant C] Salt 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) was mixed with powder to obtain Colorant C.
[Colorant D] Salt 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) was mixed with powder to obtain Colorant D.
[Colorant E] Anthraquinone blue oil-soluble dye (CI Solvent Blue 104) was used as Colorant E.
[Colorant F] An anthraquinone blue acid dye (CI Acid Blue 80) and 2-ethylhexylamine salt-forming dye were used as Colorant F.

(Example 1-1)
(1) Production of weakly laser-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 sulfuric acid concentration in accordance with the description in Japanese Patent No. 3757081; sulfate ion 1.96% by mass; volume resistivity 2.0 × 10 ¹⁰ Ω · cm) 0.1 g The mixture was placed in a tumbler and mixed with stirring for 1 hour. The obtained mixture was molded by an ordinary method using an injection molding machine (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.) at a cylinder temperature of 290 ° C. and a mold temperature of 80 ° C. One sheet of weakly laser-absorbing resin member 1 having a width of 50 mm and a thickness of 1 mm and a rectangular plate shape was produced.

(2) Production of laser light transmitting resin member 2 (second resin member) 490 g of PA66 resin and 10 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 (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.) at a cylinder temperature of 290 ° C. and a mold temperature of 80 ° C. One sheet of laser light transmitting resin member 2 having a width of 50 mm and a thickness of 1 mm and a rectangular plate shape was produced.

(Transmittance and absorbance)
The transmittance and reflectance of the molded plates of the laser light absorbing resin member and the laser light weakly absorbing resin member were measured using a spectrophotometer (trade name: V-570, manufactured by JASCO Corporation). The general absorbance (Absorbance) measured by dissolving the sample is a positive number obtained by taking the logarithm of the transmittance. When the absorbance of the molded resin member is measured as in the present invention, since the laser beam 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). Lambert-Beer's law indicating absorbance at 940 nm is expressed by the following mathematical formula (1).
(In Equation (1), T is the true transmittance, (I _O ) is the incident light intensity, (I _T ) is the transmitted light intensity, and (I _R ) is the reflected light intensity). expressed. Here, the incident light intensity I _O is 100%, further as transmitted light intensity I _T and the reflected light intensity I _R, the percentage in which transmittance measurements, by respectively substituted into Equation (1) reflectivity, Absorbance was determined, and this value was divided by the thickness of the resin member to calculate absorbance a per mm. As a result, the transmittance of the weakly laser-absorbing resin member 1 of Example 1-1 was 68.6%, the reflectance was 8.2%, and the absorbance a _{1 in} terms of 1 mm was 0.12. It was. The transmittance of the laser ray transmitting resin member 2 is 80.1% reflectivity is 9.9%, the absorbance _{a 2} of 1mm converted was 0.06.

(Melt flow rate)
The laser beam weakly 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-Determination of 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.) The measurement was performed under the conditions of a test temperature of 280 ° C. and a test load of 2.16 kgf. The measurement was performed three times, and the average of those values was calculated to determine the melt flow rate. As a result, the melt flow rate of the laser beam weakly absorbing resin member 1 was 13.4 g / 10 min.

(3) Fabrication of Laser Welded Body 10 As shown in FIG. 1, the laser light weakly absorbing resin member 1 and the laser light transmissive 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 was applied per area. Further, a 5 mm thick glass plate (laser light transmittance 90%) was placed on the surface of the laser light weakly absorbing resin member 1 to fix the three-layer resin member. Next, the laser beam L is emitted from a diode laser [wavelength: 940 nm continuous] (manufactured by Hamamatsu Photonics Co., Ltd.) having an output of 50 W substantially perpendicularly to the surface of the weakly absorbing resin member 1 from above. Irradiation was performed while scanning at a width of 1 mm, a scanning speed of 2.0 mm / second, and a scanning distance of 20 mm so as to cross a straight line from one of the long sides. Thereby, it welded in the contact part C, and the laser welded body 10 of Example 1-1 with which both the resin members 1 and 2 were integrated was obtained. This laser welded body 10 was evaluated as follows.

(Tensile test)
According to JIS K7161: 2014 plastics-testing method for tensile properties, both resin members 1 and 2 of the laser welded body 10 are moved in the longitudinal direction using a tensile testing machine (manufactured by Shimadzu Corporation, trade name: AG-50kNE). Then, they were pulled horizontally at a test speed of 10 mm / min so that they were separated, and the tensile strength was measured. The results are shown in Table 1.

(Evaluation of welded state)
The welding state was evaluated as follows. The results are shown in Table 1.
A: 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 could not be performed and a laser welded body could not be produced.

(Example 1-2)
(1) Production of weakly laser-absorbing resin member 1 499.8 g of PA66 resin and nigrosine A (sulfurate of nigrosine; sulfate ion 1.96% by mass; volume resistivity 2.0 × 10 ¹⁰ Ω · cm) The laser light transmitting resin member 1 was produced in the same manner as in Example 1-1 except that 0.2 g of was used. When the transmittance and reflectance of the 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 determined from these was 0.24. Moreover, the melt flow rate measured by operating like Example 1-1 was 14.3 g / 10min.
(2) Production of laser light transmissive resin member 2 Laser light transmissive 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 colorant was used. One sheet was prepared. When the transmittance and reflectance of the laser light transmissive 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) Production 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 the 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 evaluate the tensile test and the welded state. The results are shown in Table 1.

(Example 1-3)
(1) Production of weakly laser-absorbing resin member 1 499.7 g of PA66 resin and nigrosine B (sulfurate of nigrosine; sulfate ion 1.52% by mass; volume resistivity 2.7 × 10 ¹⁰ Ω · cm) The laser light transmitting resin member 1 was produced in the same manner as in Example 1-1 except that 0.3 g of was used. When the transmittance and reflectance of the 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. Moreover, the melt flow rate measured by operating like Example 1-1 was 14.8 g / 10min.
(2) Production of laser light transmissive resin member 2 A single laser light transmissive resin member 2 was produced in the same manner as in Example 1-2.
(3) Production 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 the 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 evaluate the tensile test and the welded state. 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 (sulfurate of nigrosine; sulfate ion 0.70% by mass; volume resistivity 0.9 × 10 ¹⁰ Ω · cm) The laser light transmitting 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 transmissive resin member 1 were measured 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. Further, the melt flow rate measured by operating in the same manner as in Example 1-1 was 15.4 g / 10 min.
(2) Production of laser light transmissive resin member 2 A single laser light transmissive resin member 2 was produced in the same manner as in Example 1-2.
(3) Production 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 the 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 evaluate the tensile test and the welded state. 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 performed, and Examples 1-5 to 1- 12 and Comparative Example 1-1 to 1-5 were prepared as a resin member, and the transmittance and reflectance were measured in the same manner as in Example 1-1. Asked. Further, 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 welds of Examples 1-5 to 1-12 were operated in the same manner as in Example 1-1 except that the laser output and the scanning speed were changed as shown in Table 1. Was made. Further, these laser welds were operated in the same manner as in Example 1-1 to evaluate the tensile test and the welded state. On the other hand, the resin members of Comparative Examples 1-1 to 1-5 that were overlapped by operating in the same manner as in Example 1-1 were irradiated with laser light, but the resin members were not welded together to obtain a laser welded body. I could not. 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, respectively.

Laser light weakly absorbing resin member 1 having an absorbance a _{1 of} 0.1 to 0.5 and laser light transmitting resin member having an absorbance a ₂ of less than 0.1 (specifically 0.01 to 0.09) No. 2 was welded by irradiation with laser light having a relatively low output, and the laser welded body of Example had no welding marks and had high tensile strength. On the other hand, in the comparative example using the laser light transmitting resin member having an absorbance a _{1 of} less than 0.1, the resin members could not be welded to each other even when irradiated with high output laser light. Further, in the comparative example using the laser beam weakly absorbing resin member having an absorbance a ₁ exceeding 0.5, the surface layer of the laser beam weakly absorbing resin member is observed by laser light irradiation, or the molten pool is expanded. Insufficient weld strength could not be achieved.

  FIG. 8 (a) shows an enlarged photograph of a section of Example 1-3, and FIG. 8 (b) shows an enlarged cross-sectional photograph of the fused part of the laser welded body 10 of Example 1-4. In the figure, white arrows indicate the irradiation direction and position of laser light. The melted portion having a substantially elliptical cross section spreads widely in the laser light weakly absorbing resin member 1 disposed on the laser light incident side, and the laser light passes through a contact portion C between this and the laser light transmissive resin member 2. The permeable resin member 2 is reached. Thereby, both the resin members 1 and 2 are welded and integrated. Since this welded part extends to the laser light weakly absorbing resin member 1 side rather than the laser light transmitting resin member 2, it is melted in a wider and deeper range by the laser light weakly absorbing resin member 1 by laser light irradiation. It was found that a molten pool was formed.

(Example 2-1)
(1) Production of weakly laser-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) Grey IR-B CI Solvent Black 7 high-heat-resistant nigrosine; volume resistivity 1.2 × 10 ¹¹ Ω · cm) is placed in a stainless steel tumbler and stirred for 1 hour. Mixed. The obtained mixture was molded by an ordinary method using an injection molding machine (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.) at a cylinder temperature of 210 ° C. and a mold temperature of 40 ° C. One laser light weakly absorbing resin member 1 having a width of 50 mm and a thickness of 1.5 mm was produced.

(2) Production of Laser Light-Transparent Resin Member 2 500 g of PP resin is 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 is 80 mm long × 50 mm wide × One laser light transmissive resin member 2 having a thickness of 1.5 mm was produced.

  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, and the absorbance was determined. The results are shown in Table 3.

(3) Fabrication of Laser Welded Body 10 As shown in FIG. 1, the laser light weakly absorbing resin member 1 and the laser light transmissive 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 was applied per area. Further, a 5 mm thick glass plate (laser light transmittance 90%) was placed on the surface of the laser light weakly absorbing resin member 1 to fix the three-layer resin member. Next, laser light L is emitted from a diode laser [wavelength: 940 nm continuous] (manufactured by Fine Devices Co., Ltd.) having an output of 50 W substantially perpendicularly to the surface of the weakly absorbent resin member 1 from above. Irradiation was performed while scanning at a width of 1 mm, a scanning speed of 2.0 mm / second, and a scanning distance of 20 mm so as to cross a straight line from one of the long sides. Thereby, it welded in the contact part C, and the laser welded body 10 of Example 2-1 with which both the resin members 1 and 2 were integrated was obtained. About this laser welded body 10, it operated similarly to Example 1-1 and evaluated the tensile test and the welding state. The results are shown in Table 3.

(Examples 2-2 and 2-3)
Except that the amount of nigrosine was changed as shown in Table 3, the 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. The same procedure as in Example 2-1 was performed, and the transmittance was measured to determine the absorbance. Also, using this resin member, the laser welds of Examples 2-2 and 2-3 were operated in the same manner as in Example 2-1, except that the scanning speed of the laser beam was changed as shown in Table 3. 10 was produced. Furthermore, it operated similarly to Example 2-1, and evaluated the tension test and the welding 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 was performed except that the amount of PP resin was 498.0 g and that of nigrosine was 2.0 g. A laser light weakly absorbing resin member 1 was produced.

(2) Production of Laser Light-Transmissible Resin Member 2 495.0 g of PP resin and 5.0 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 using an injection molding machine at a cylinder temperature of 210 ° C. and a mold temperature of 40 ° C., and was 80 mm long × 50 mm wide × 1 mm thick rectangular plate-shaped laser light transmitting property. One resin member 2 was produced.

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

(3) Production 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 made. Furthermore, it operated similarly to Example 2-1, and evaluated the tension test and the welding state. The results are shown in Table 3.

(Comparative Example 2)
Except that nigrosine was not used and 500 g of PP resin was used, a laser light weakly absorbing resin member was produced in the same manner as in Example 2-1. Further, a laser light transmitting resin member was produced by operating in the same manner as in Example 2-1. By operating in the same manner as in Example 2-1, the transmittance of these resin members was measured to determine the absorbance. Moreover, although the laser beam was irradiated to these resin members that were operated and overlapped in the same manner as in Example 2-1, 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 laser beam weakly absorbing resin member 1 having an absorbance a _{1 of} 0.1 to 0.5 have no welding marks and have high strength. A good welding state in which the members were welded to each other was shown. On the other hand, in Comparative Example 2 using a resin member having an absorbance a ₁ of less than 0.1, the resin members could not be welded together by laser light irradiation.

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

(2) Production of laser light transmitting resin member 2 500.0 g of PBT resin was placed in a stainless steel 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., and a laser light transmitting resin member 2 having a length of 80 mm × width of 50 mm × thickness of 1.5 mm is 1 A sheet 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 determine the absorbance. The results are shown in Table 4.

(3) Fabrication of Laser Welded Body 10 As shown in FIG. 1, the laser light weakly absorbing resin member 1 and the laser light transmissive 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 was applied per area. Further, a 5 mm thick glass plate (laser light transmittance 90%) was placed on the surface of the laser light weakly absorbing resin member 1 to fix the three-layer resin member. Next, laser light L is emitted from a diode laser [wavelength: 940 nm continuous] (manufactured by Fine Devices Co., Ltd.) having an output of 50 W substantially perpendicularly to the surface of the weakly absorbent resin member 1 from above. Irradiation was performed while scanning at a width of 1 mm, a scanning speed of 2.0 mm / second, and a scanning distance of 20 mm so as to cross a straight line from one of the long sides. Thereby, it welded in the contact part C, and the laser welded body 10 of Example 3-1 with which both the resin members 1 and 2 were integrated was obtained. About this laser welded body 10, it operated similarly to Example 1-1 and evaluated the tensile test and the welding state. The results are shown in Table 4.

(Example 3-2)
Except that the amount of nigrosine was changed as shown in Table 4, it was operated in the same manner as in Example 3-1, and a resin member used for preparing the laser welded body of Example 3-2 was prepared. By operating in the same manner as in Example 3-1, the transmittance was measured and the absorbance was determined. Further, using this resin member, the laser welded body 10 of Example 3-2 was manufactured in the same manner as in Example 3-1, except that the scanning speed of the laser beam was changed as shown in Table 4. . Furthermore, it operated similarly to Example 3-1, and evaluated the tensile test and the welding state. The results are shown in Table 4.

(Example 3-3)
(1) Production of Laser Light Weak Absorbent Resin Member 1 The same operation as in Example 3-1 was performed to produce one piece of laser light weakly absorbable resin member 1.

(2) Production of Laser Light Transmissible Resin Member 2 497.0 g of PBT resin and 3.0 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 using an injection molding machine at a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C., and was 80 mm long × 50 mm wide × 1 mm thick rectangular plate-shaped laser light transmitting property. 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 determine the absorbance. The results are shown in Table 5.

(3) Production of Laser Welded Body 10 The laser welded body 10 of Example 3-3 was operated in the same manner as in Example 3-1, using the laser light weakly absorbing resin member 1 and the laser light transmitting resin member 2. Was made. Furthermore, it operated similarly to Example 1-1 and evaluated the tensile test and the welding state. The results are shown in Table 4.

(Comparative Example 3)
A laser light weakly absorbable resin member was produced in the same manner as in Example 3-1, except that nigrosine was not added and 500 g of PBT resin was used. In addition, a laser light transmitting 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 determine the absorbance. Moreover, although the laser beam was irradiated to these resin members that were operated and overlapped in the same manner as in Example 3-1, 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 body 10 of Examples 3-1 to 3-3 using the laser beam weakly absorbing resin member 1 having an absorbance a _{1 of} 0.1 to 0.5 has no weld mark and is in a good welded state. showed that. On the other hand, Comparative Example absorbance a ₁ has a resin member less than 0.1 3 failed welding resin members to each other by laser beam irradiation.

(Example 4-1)
(1) Production of weakly laser-absorbing resin member 1 499.9 g of polycarbonate (PC) resin (manufactured by Teijin Ltd., trade name: Panlite (registered trademark) 1225Y) and modified nigrosine (alkylbenzenesulfonic acid: Nigrosine = 20:80 (mass ratio) 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 using an injection molding machine (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.) at a cylinder temperature of 300 ° C. and a mold temperature of 100 ° C. One laser light weakly absorbing resin member 1 having a width of 50 mm and a thickness of 2 mm was produced.

(2) Production of Laser Light Transmissible 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 using an injection molding machine at a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C. to produce one piece of a laser light transmissive resin member 2 having a length of 80 mm × width of 50 mm × thickness of 2 mm. did.

  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, and the absorbance was determined. The results are shown in Table 5.

(3) Fabrication of Laser Welded Body 10 As shown in FIG. 1, the laser light weakly absorbing resin member 1 and the laser light transmissive 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 was applied per area. Further, a 5 mm thick glass plate (laser light transmittance 90%) was placed on the surface of the laser light weakly absorbing resin member 1 to fix the three-layer resin member. Next, laser light L is emitted from a diode laser [wavelength: 940 nm continuous] (manufactured by Fine Devices Co., Ltd.) having an output of 50 W substantially perpendicularly to the surface of the weakly absorbent resin member 1 from above. Irradiation was performed while scanning at a width of 1 mm, a scanning speed of 2.0 mm / second, and a scanning distance of 20 mm so as to cross a straight line from one of the long sides. Thereby, welding was performed at the contact site C, and the laser welded body 10 of Example 4-1 in which both the resin members 1 and 2 were integrated was obtained. About this laser welded body 10, it operated similarly to Example 1-1 and evaluated the tensile test and the welding state. The results are shown in Table 5.

(Example 4-2)
The amount of PC resin was set to 499.75 g, and 0.25 g of modified nigrosine (mixed nigrosine CI Solvent Black 5 of alkylbenzenesulfonic acid: nigrosine = 30: 70 (mass ratio)) was used as nigrosine. Except for the above, the laser light weakly absorbing resin member 1 was produced in the same manner as in Example 4-1. In addition, the laser light transmitting resin member 2 was produced in the same manner as in Example 4-1. 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 determine the absorbance. The results are shown in Table 5.

  The laser welded body 10 of Example 4-2 was obtained by operating in the same manner as in Example 4-1. About this laser welded body 10, it operated similarly to Example 4-1, and the tension test and the evaluation of the welding state were performed. The results are shown in Table 5.

(Example 4-3)
First, the laser light weakly absorbable resin member 1 was produced in the same manner as in Example 4-1. Next, 490.0 g of PC resin and 10 g of 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, a laser light transmitting resin member 2 was produced in the same manner as in Example 4-1. 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 determine the absorbance. The results are shown in Table 5.

  The laser welded body 10 of Example 4-3 was obtained by operating in the same manner as in Example 4-1. About this laser welded body 10, it operated similarly to Example 4-1, and the tension test and the evaluation of the welding state were performed. 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 placed in a stainless steel tumbler and mixed with stirring for 1 hour. Other than that was operated in the same manner as in Example 4-1, and a laser light weakly absorbing resin member was produced. Further, a laser light transmissive resin member was produced in the same manner as in Example 4-1. By operating in the same manner as in Example 4-1, the transmittance of these resin members was measured to determine the absorbance. Moreover, although the laser beam was irradiated to these resin members which were operated and overlapped similarly to Example 4-1, 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 body 10 of Examples 4-1 to 4-3 using the laser beam weakly absorbing resin member 1 having an absorbance a ₁ of 0.1 or 0.25 has no welding mark and is in a good welding state. showed that. On the other hand, Comparative Example absorbance a ₁ has a resin member is less than 0.1 4 failed welding resin members to each other by laser beam irradiation.

(Example 5-1)
(1) Production of a weakly laser-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 (Patent No. 3757081) Nigrosine sulfate synthesized by changing the concentration of sulfuric acid; 0.2 g of sulfate ion (1.96% by mass; 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 using an injection molding machine (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.) at a cylinder temperature of 270 ° C. and a mold temperature of 60 ° C. As shown in FIG. 9 (a), a lid 8 that is a weakly laser-absorbing resin member having a disk-shaped head 8a and a sleeve 4b that is coaxial with the head 8a. Was made. The outer dimension of the head 8a is an outer diameter of 50 mm and a thickness of 2 mm. The outer dimensions of the sleeve 8b are an outer diameter of 42 mm and a height of 4 mm. The lid body 8 has a step portion 8c having a width of 4 mm on the outer peripheral surface due to a difference in outer diameter between the head portion 8a and the sleeve portion 8b.

(2) Production of laser light transmitting resin member 500.0 g of PA66 resin was put in a stainless steel tumbler and stirred for 1 hour. This is 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 round 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, which is a laser light transmitting resin member, was produced. The outer dimension of the cylindrical container 7 is an outer diameter of 50 mm × a height of 35 mm, and its inner dimension is an inner diameter of 43 mm × a height of 32 mm. The cylindrical container 7 has a thickness of 3 mm.

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

(3) Production of laser welded body The sleeve 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 longitudinal sectional view of the lid 8 and the cylindrical container 7, the contact portion C where the stepped portion 8c and the opening edge 7a are in contact with each other, and the sleeve A butt portion B was formed in which the portion 8b and the inner wall surface of the cylindrical container 7 were abutted. The butt portion B is formed by the difference in size between the outer diameter of the sleeve 8b and the inner diameter of the cylindrical container 7, and the shift of the center axis between the fitted lid 8 and the cylindrical container 7, and the sleeve 8b and the cylindrical container. 7 has a portion where the inner wall surface is in surface contact and a portion where slight play (gap) is generated.

  Laser light L from a diode laser with a power of 50 W (wavelength: 940 nm continuous) (manufactured by Hamamatsu Photonics Co., Ltd.) from the upper part of the lid 4 toward the contact part C substantially perpendicular to the surface thereof Irradiation was performed while scanning at a scanning speed of 2.0 mm / sec to draw a circle along C. Thereby, welding was performed at the contact site C, and the laser welded body 10 of Example 5-1 in which the lid 8 and the cylindrical container 7 were integrated was obtained. About this laser welding body 10, it operated like Example 1-1 and the welding state was evaluated. The results are shown in Table 6.

(Example 5-2)
(1) Preparation of laser light weakly absorbing resin member Except that the amount of PA66 resin was 499.7 g and the amount of nigrosine was 0.3 g, the same operation as in Example 5-1, The lid body 8 shown in FIG. 9A was produced.

(2) Production of laser light transmitting resin member Except that the amount of PA66 resin was 497.0 g, and 3.0 g of Colorant C was used, the same operation as in Example 5-1 was performed. A cylindrical container 7 shown in FIG.

  The transmittance and 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 in the same manner as in Example 5-1, respectively. The results are shown in Table 6.

(3) Production of Laser Welded Body 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 laser beam L was set to 3.0 mm / second. It was. This laser welded body 10 was operated in the same manner as in Example 5-1, and the welded state was evaluated. The results are shown in Table 6.

  As shown in Table 6, the laser welded body 10 is firmly sealed in the cylindrical container 7 by being well laser welded at the abutting portion B of the lid 8 and the cylindrical container 7. It was.

  The laser welded body of the present invention includes, for example, an interior instrument panel, a resonator (silencer) in an engine room, an engine cover, a driving device, a brake device, a vehicle housing, and a transportation device such as an electrical component ( Parts for automobiles in particular, parts for electrical and electronic equipment, parts for industrial machinery, medical tubes used for infusions of infusions and nutrients, food packaging materials such as spout pouches containing liquid foods and beverage compositions Since it can be suitably and widely applied to household appliance parts such as PET bottle labels and housings, the industrial applicability is very high.

1 is a laser light weakly absorbing resin member, 1a and 1b are laser light weakly 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. Piece, 2c is the second joint part, 3 is a plastic bottle, 4 is a label, 5a and 5b are cylindrical members, 6 is a strip member, 7 is a cylindrical container, 7a is an opening edge, 8 is a lid, 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 (15)

A _first resin member, which is a laser light irradiation side resin member containing a thermoplastic resin and a laser light absorber and having an absorbance a _{1 of} 0.1 to 0.5, and the same or different kind of the thermoplastic resin. a second resin member having an absorbance a ₂ of less than 0.1 and containing a thermoplastic resin, at least part of the contact portion is formed by overlapping, characterized in that it is laser welded Laser welded body. _2. The laser welded body according to claim ₁ , wherein an absorbance ratio a ₁ / a ₂ between the absorbance a ₁ and the absorbance a ₂ is 1.3 to 45. 3. The absorbance _{a 2} is laser-welded article according to claim 1 or 2, characterized in that a 0.01 to 0.09.   The end portions of the first resin member and / or the end portions of the second resin member are adjacent to and in contact with each other, and the end portions are lasers. The laser welded body according to any one of claims 1 to 3, wherein the laser welded body is welded.   5. The laser welded body according to claim 4, wherein the first resin member and / or the second resin member is divided into a plurality of resin member pieces that are in contact with each other at the contact portion. The second resin member is divided into two resin member pieces, and their absorbance a _2-1 and absorbance a _2-2 are 0.05 to 0.09, and the absorbance a ₁ and absorbance a 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 5.   3. The laser according to claim 1, wherein the first resin member and the second resin member have a butting portion formed by being butted at their end portions. 4. Welded body.   The laser welder according to any one of claims 1 to 7, wherein the laser light absorbent is nigrosine.   The laser welded body according to claim 8, wherein the nigrosine is a nigrosine sulfate.   The laser welded body according to any one of claims 1 to 9, wherein the second resin member contains a colorant containing anthraquinone and / or nigrosine. 11. The laser welded body according to claim 8, wherein the nigrosine has a volume resistivity of 0.5 × 10 ^{9 to} 5.0 × 10 ¹¹ Ω · cm.   12. The thermoplastic resin according to claim 1, wherein 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. The laser welded body described.   13. At least one part of the said contact site | part currently welded by laser has the melt | fusion site | part spread on the 1st resin member side rather than the said 2nd resin member, The any one of Claim 1 to 12 characterized by the above-mentioned. The laser welded body according to crab. A first resin member containing a thermoplastic resin and nigrosine and a second resin member containing a thermoplastic resin of the same or different type as the thermoplastic resin and having a lower absorbance than the first resin member are overlapped Forming contact sites at their interfaces and / or butting their ends together to form a butting site;
The first resin member and the second resin member are welded by irradiating the contact part and / or the butting part with laser light from the first resin member side to melt the contact part and / or the butting part. A method for producing a laser welded body.   The method for producing a laser welded body according to claim 14, wherein the laser beam is irradiated to cause the first resin member to melt and then grow the melt toward the contact portion.