JP6126563B2 - Joining method using laser light and intermediate member for laser joining - Google Patents

Description

  The present invention relates to a bonding method using laser light and an intermediate member for laser bonding.

  2. Description of the Related Art Conventionally, a joining method using laser light irradiation has been widely used as a method for joining two members, for example, at the manufacturing site of home appliances or household equipment (for example, see Patent Documents 1 to 3).

  In the joining methods disclosed in Patent Documents 1 to 3, an intermediate member for laser joining is interposed between the first member and the second member that transmit the laser light prior to the irradiation of the laser light. Thereafter, the laser beam is irradiated from the first member side to heat and melt or soften the laser bonding intermediate member, and the first member and the second member are bonded by this intermediate member.

  The intermediate member for laser bonding of Patent Document 1 is made of an elastomer. Use of this intermediate member for laser bonding is effective in that the stress generated at the bonding interface can be reduced.

  The intermediate member for laser bonding disclosed in Patent Document 2 is a multilayer sheet. Use of this intermediate member for laser bonding is effective in that various materials can be easily bonded.

  The intermediate member for laser bonding of Patent Document 3 has adhesiveness. Use of this intermediate member for laser bonding is effective in that the first and second members can be temporarily fixed before bonding and the bonding strength can be increased.

JP 2008-7584 A JP 2009-173023 A International Publication No. 2008/044349 Pamphlet

  By interposing the intermediate member for laser joining, there are various advantages as described above.

  However, when an intermediate member for laser bonding having a laser beam absorption rate too high is interposed, almost all of the laser light is absorbed by the intermediate member for laser bonding, and the surface of the intermediate member for laser bonding (first Heat generation on the surface located on the member side is larger than that on the back surface (surface located on the second member side). In this case, although the first member side is softened or melted, it is considered that poor softening and poor melting occur on the second member side, and sufficient bonding strength cannot be obtained.

  Conversely, when an intermediate member for laser bonding whose laser beam absorption rate is too low is interposed, the energy of the laser beam is wasted, the energy efficiency is poor, and the second member has laser beam absorbability. In some cases, the heat of the member becomes too high, and the second member is damaged by the heat.

  This invention is made | formed in view of this point, The place made into the objective is the 1st member and 2nd in the state which interposed the intermediate member for laser joining between the 1st member and the 2nd member. When joining the members, by securely softening or melting both the first member side of the laser joining intermediate member and the second member side of the laser joining intermediate member, the first member and the second member The purpose is to sufficiently increase the bonding strength.

  In order to achieve the above object, in the first invention, as an invention of a bonding method using laser light, an intermediate member for laser bonding used in the method is a first laser light absorption formed on the first member side. A first laser light absorption layer, a second laser light absorption layer formed on the second member side, and a laser light transmission layer formed between the laser light absorption layers. The rate was set to 20% or more, and the laser light absorption rate of the second laser light absorption layer was set to 20% or more.

According to a first aspect of the present invention, an intermediate member for laser bonding having laser light absorptivity is interposed between a first member having laser light transmissivity and a second member having laser light transmissivity or laser light absorptivity. In the bonding method using laser light for bonding the first member and the second member with the intermediate member for laser bonding, the intermediate member for laser bonding is formed on the first member side and absorbs laser light. Between the first laser light absorption layer, the second laser light absorption layer formed on the second member side and having laser light absorption, and between the first laser light absorption layer and the second laser light absorption layer is formed and a colorless transparent laser-transmissible layer having a laser ray transmitting wavelength 940 nm, the first laser light-absorbing layer and the second laser light-absorbing layer, styrenic et A laser light absorber selected from the group consisting of organic dyes, organic pigments, and carbon black is added to an elastomer selected from the group consisting of a streamer, a polyester-based elastomer, a urethane-based elastomer, and an acrylic elastomer, and The laser light transmission layer is made of a resin selected from the group consisting of polypropylene, polyethylene, polycarbonate, polybutene, vinyl chloride, polyacetal, polyethylene terephthalate, and acrylic resin, and the entire laser joining intermediate member has a wavelength of 940 nm. The light absorption rate is set to 40% or more and 60% or less, the laser light absorption rate at a wavelength of 940 nm of the first laser light absorption layer is set to 20% or more, and the wavelength of the second laser light absorption layer is set to 940 nm. Laser light absorption The rate is set to 20% or higher, and then the first member, the intermediate member for laser bonding, and the intermediate member for laser bonding are interposed between the first member and the second member. The second member is overlapped, and then the laser beam is irradiated from the first member side.

  According to this configuration, most of the laser light irradiated from the first member side passes through the first member. The laser light transmitted through the first member reaches the laser bonding intermediate member and is absorbed by the first laser light absorption layer. Since the first laser light absorption layer has a laser light absorption rate of 20% or more, not all of the laser light is absorbed, and a part is absorbed by the first laser light absorption layer. The remaining laser light passes through the laser light transmission layer and reaches the second laser light absorption layer. In the second laser light absorption layer, since the laser light absorption rate is 20% or more, the remaining laser light is sufficiently absorbed.

  Therefore, it is possible to balance well the amount of heat generated on the first member side and the amount of heat generated on the second member side in the laser joining intermediate member. This makes it possible to soften or melt both the first member side and the second member side of the intermediate member for laser bonding.

  In order to achieve the above object, in the second invention, as an invention of an intermediate member for laser bonding, a first laser light absorption layer formed on the first member side and a second laser beam formed on the second member side. 2 laser light absorption layers and a laser light transmission layer formed between both laser light absorption layers, the laser light absorption rate of the first laser light absorption layer is set to 20% or more, and the second laser The laser absorption rate of the light absorption layer was set to 20% or more.

According to a second aspect of the present invention, the first member and the second member are formed so as to be interposed between a first member having laser beam transparency and a second member having laser beam transmittance or laser beam absorption property. In an intermediate member for laser bonding for bonding members, a first laser light absorption layer formed on the first member side and having laser light absorption property and a laser light absorption property formed on the second member side. A second laser light absorption layer, and a colorless and transparent laser light transmission layer formed between the first laser light absorption layer and the second laser light absorption layer and having a laser light transmittance of 940 nm. The first laser light absorption layer and the second laser light absorption layer are made of a styrene elastomer, a polyester elastomer, a urethane elastomer, and an acrylic elastomer. A laser light absorber selected from the group consisting of organic dyes, organic pigments and carbon black is added to the elastomer selected from the above, and the laser light transmission layer is made of polypropylene, polyethylene, polycarbonate, polybutene, vinyl chloride. , Comprising a resin selected from the group consisting of polyacetal, polyethylene terephthalate and acrylic resin, and the total laser light absorption rate of the first laser light absorption layer, the second laser light absorption layer and the laser light transmission layer, It is set to 40% or more and 60% or less when irradiated with laser light having a wavelength of 940 nm, and the laser light absorption rate of the first laser light absorbing layer is set to 20% or more when irradiated with laser light having a wavelength of 940 nm. The laser light absorptivity of the second laser light absorbing layer has a wavelength of 9 And it is characterized in that it is set to 20% or more when irradiated with a laser beam of 0 nm.

  According to this configuration, similarly to the first invention, the amount of heat generated on the first member side and the amount of heat generated on the second member side in the intermediate member for laser bonding can be well balanced.

  According to the first invention, the intermediate member for laser bonding includes a first laser light absorption layer formed on the first member side, a second laser light absorption layer formed on the second member side, and both laser beams. A laser light transmission layer formed between the absorption layers, the laser light absorption rate of the first laser light absorption layer is set to 20% or more, and the laser light absorption rate of the second laser light absorption layer is 20 % Or more was set. Thereby, since both the 1st member side and the 2nd member side of the intermediate member for laser joining can be moderately softened or melted, the joining strength of the 1st member and the 2nd member can fully be raised.

  According to the second invention, similarly to the first invention, both the first member side and the second member side of the intermediate member for laser bonding can be appropriately softened or melted. The joining strength of the two members can be sufficiently increased.

It is sectional drawing of the joined article concerning a reference example. It is a figure which shows the state before superimposing the 1st member concerning a reference example, the intermediate member for laser joining, and the 2nd member. FIG. 2 is a view corresponding to FIG. 1 according to the embodiment. FIG. 3 is a view corresponding to FIG. 2 according to the embodiment. It is a figure explaining the joining process of an Example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

(Reference example)
FIG. 1 shows a bonded product A obtained by a bonding method using laser light according to a reference example. The joined product A is obtained by joining the first member 1 and the second member 2 with the intermediate member 3 for laser joining.

  As shown also in FIG. 2, the 1st member 1 is the board | plate material comprised with the resin material which has a laser beam permeability which lets a laser beam pass. Laser light transmission is a property that allows the laser beam to pass through without being reflected or absorbed, or allows the remaining laser beam to pass through without being melted even if the laser beam is partially transmitted and / or reflected. Including those that transmit all of the laser light. Examples of the resin material constituting the first member 1 include polypropylene, polyethylene, polycarbonate, polybudene, vinyl chloride, polyacetal, polyethylene terephthalate, and acrylic resin. In the reference example, the first member 1 is colorless and transparent.

  The 2nd member 2 is a board | plate material comprised with the material which has a laser beam absorptivity which absorbs a laser beam. Laser light absorptivity is laser light impermeability that does not allow laser light to pass through, and refers to the property of absorbing the remainder even when part of the laser light is transmitted and / or reflected. As a material constituting the second member 2, for example, the same material as that of the first member 1 can be used.

  The material constituting the second member 2 is mixed with a laser light absorber in order to impart laser light absorbability. Examples of the laser light absorber include organic dyes and organic pigments, commercially available laser light absorbers, carbon black, and the like. The laser beam absorptivity of the second member 2 can be arbitrarily set depending on the type and blending amount of the laser beam absorber. In this reference example, the laser light absorption rate of the second member 2 is set to 60% or more.

  The intermediate member 3 for laser joining is made of a hot melt material that softens or melts when heated by laser light, and is a high-molecular substance (elastomer) that exhibits rubber elasticity near room temperature and its alloy, and is thermoplastic. It is what has. As a material constituting the intermediate member 3 for laser joining, for example, a styrene-based, polyester-based, urethane-based, acrylic-based elastomer, or the like or an alloy thereof is preferable. In particular, examples of the styrene elastomer include diblocks and triblocks such as styrene / butadiene, styrene / isoprene, and styrene / ethylenebutylene.

  A laser light absorbent is mixed in the material constituting the intermediate member 3 for laser bonding. As the laser light absorber, the same one mixed with the second member 2 can be used. The laser beam absorptivity of the intermediate member 3 for laser bonding can be arbitrarily set according to the type and blending amount of the laser beam absorber. In this reference example, the laser light absorption rate of the intermediate member 3 for laser bonding is set to 40% or more and 60% or less.

  Further, the thickness of the intermediate member 3 for laser bonding is preferably 10 μm or more and 2000 μm or less, for example, but is not limited to this range.

  Next, the manufacturing procedure of the joined product A will be described. First, the intermediate member 3 for laser bonding is placed on the surface (bonding surface) of the second member 2 on the first member 1 side.

  Then, as shown in FIG. 1, the 1st member 1, the intermediate member 3 for laser joining, and the 2nd member 2 are piled up. The first member 1 and the second member 2 are clamped with a predetermined force using a known clamping jig (not shown).

  Thereafter, the laser beam L is irradiated. As the type of the laser beam L, for example, any of a gas laser, a solid laser, a semiconductor laser, and the like may be used, and the type of the laser beam L is not limited. The type of the laser beam L can be appropriately selected according to the material, thickness, and the like of the first member 1 and the second member 2. Further, the laser beam L may be composed of one wavelength, or may have two or more wavelengths.

  Since the first member 1 has laser beam transparency, almost all of the irradiated laser beam L passes through the first member 1. The laser light L transmitted through the first member 1 reaches the intermediate member 3 for laser bonding. Since the laser beam absorptivity of the laser bonding intermediate member 3 is 40% or more and 60% or less, 40% or more and 60% or less of the laser light L is absorbed by the laser bonding intermediate member 3. Thereby, the surface (surface located in the 1st member 1 side) of the intermediate member 3 for laser joining is heated and fuse | melted (the outline of a melting range is shown with a virtual line). The back surface of the first member 1 (the surface located on the laser bonding intermediate member 3) is melted by the heat of the surface of the laser bonding intermediate member 3. Thereby, the resin of the 1st member 1 and the resin of the intermediate member 3 for laser joining are mixed.

  The remaining laser light L transmitted through the laser joining intermediate member 3 reaches the second member 2. Since the laser light absorption rate of the second member 2 is 60% or more, the remaining laser light L is almost absorbed by the second member 2. Thereby, the surface located in the intermediate member 3 for laser joining in the 2nd member 2 fuse | melts. The intermediate member 3 for laser bonding is melted by the heat of the second member 2. Thereby, the resin of the 2nd member 2 and the resin of the intermediate member 3 for laser joining are mixed.

  Here, the results of the joining test conducted by the inventors changing the laser light absorption rate of the intermediate member 3 for laser bonding and the laser light absorption rate of the second member 2 to various values will be described.

  If the laser light absorption rate of the intermediate member 3 for laser bonding is set to a value smaller than 40%, the heat generation of the second member 2 becomes too large, only the second member 2 side melts, and the first member 1 side does not melt. . Accordingly, sufficient bonding strength between the laser bonding intermediate member 3 and the first member 1 cannot be obtained. Furthermore, the second member 2 may generate too much heat, and the second member 2 may be damaged by heat.

  Further, when the laser light absorption rate of the intermediate member 3 for laser bonding is set to a value larger than 60%, the heat generation on the first member 1 side becomes too large, only the first member 1 side is melted, and the second member 2 side is melted. It will not melt. Accordingly, sufficient bonding strength between the laser bonding intermediate member 3 and the second member 2 cannot be obtained.

  That is, in the reference example, the laser beam absorption rate of the intermediate member 3 for laser bonding is set to 40% or more and 60% or less, and the laser beam absorption rate of the second member 2 is set to 60% or more. By reducing the difference between the heat generation amount on the first member 1 side in the intermediate member 3 and the heat generation amount on the laser joining intermediate member 3 side in the second member 2, it is possible to balance both the heat generation amounts well. . Thereby, it is possible to melt both the first member 1 side and the second member 2 side of the intermediate member 3 for laser bonding.

  When the resin is solidified by cooling after irradiation with the laser beam L, a joined product A in which the first member 1 and the second member 2 are joined via the intermediate member 3 for laser joining is obtained.

  As described above, according to this reference example, the laser light absorption rate of the second member 2 is set to 60% or more, and the laser light absorption rate of the intermediate member 3 for laser bonding is set to 40% or more and 60% or less. Therefore, the amount of heat generated on the first member 1 side in the laser joining intermediate member 3 and the amount of heat generated on the laser joining intermediate member 3 side in the second member 2 can be well balanced. Thereby, since both the 1st member 1 side and the 2nd member 2 side of the intermediate member 3 for laser joining can be fuse | melted moderately, the joining strength of the 1st member 1 and the 2nd member 2 is fully raised. Can do.

  In the reference example, at the time of bonding, the laser beam L having such an intensity that the intermediate member 3 for laser bonding is softened may be irradiated.

(Embodiment)
FIG. 3 shows a bonded product A obtained by the bonding method using laser light according to the embodiment. In the embodiment, the point of using the intermediate member 30 for laser bonding different from the intermediate member 3 for laser bonding used in the reference example, and the point that the second member 2 may have laser light transmittance, It is different from the reference example. Hereinafter, parts different from the reference example will be described in detail.

  That is, the intermediate member 30 for laser bonding according to the embodiment has a three-layer structure as shown in FIG. The laser joining intermediate member 3 is formed on the side in contact with the first member 1 and formed on the side in contact with the first laser light absorbing layer 31 having the laser light absorbing property and the second member 2 to provide the laser light absorbing property. A second laser light absorption layer 32, and a laser light transmission layer 33 formed between the first laser light absorption layer 31 and the second laser light absorption layer 32 and having a property of transmitting laser light. .

  The first laser light absorption layer 31, the second laser light absorption layer 32, and the laser light transmission layer 33 are made of a resin similar to the resin constituting the first member 1 or the second member 2. The first laser light absorption layer 31 and the second laser light absorption layer 32 are mixed with a laser light absorber. The laser light absorbing material is the same as that of the reference example. The laser light absorption rate of the first laser light absorption layer 31 is set to 20% or more. The laser light absorption rate of the second laser light absorption layer 32 is set to 20% or more.

  The laser light transmission layer 33 is colorless and transparent.

  The laser light absorptance of the entire laser joining intermediate member 30 is obtained as follows.

  For convenience, it is assumed that the laser absorption rate of the first laser light absorption layer 31 and the second laser light absorption layer 32 are both 20%. When the laser beam L is irradiated from the first laser beam absorption layer 31 side, 20% of the laser beam L is first absorbed by the first laser beam absorption layer 31. Thereafter, the remaining 80% of the laser light L passes through the laser light transmission layer 33 and then passes through the second laser light absorption layer 32. In the second laser light absorption layer 32, 20% is further absorbed. Accordingly, 80% × 20% = 16% of the total laser light L is absorbed by the second laser light absorption layer 32. Assuming that the absorptance of the laser light transmission layer 33 is not taken into consideration in the entire intermediate member 30 for laser bonding, the absorptance is 20% + 16% = 36%.

  Next, the manufacturing procedure of the joined product A will be described. First, the laser bonding intermediate member 30 is placed on the surface (bonding surface) of the second member 2 on the first member 1 side.

  Then, as shown in FIG. 1, the 1st member 1, the intermediate member 3 for laser joining, and the 2nd member 2 are piled up. The first member 1 and the second member 2 are clamped with a predetermined force using a known clamping jig (not shown).

  Thereafter, the laser beam L is irradiated. Almost all of the irradiated laser light L passes through the first member 1. The laser light L transmitted through the first member 1 reaches the first laser light absorption layer 31 of the intermediate member 30 for laser bonding.

  Since the laser light absorption rate of the first laser light absorption layer 31 is 20% or more, 20% or more of the laser light L is absorbed by the first laser light absorption layer 31. Thereby, the surface (surface located in the 1st member 1 side) of the intermediate member 3 for laser joining is heated and fuse | melted (the outline of a melting range is shown with a virtual line). The back surface of the first member 1 (the surface located on the laser bonding intermediate member 3) is melted by the heat of the surface of the laser bonding intermediate member 3. Thereby, the resin of the 1st member 1 and the resin of the intermediate member 3 for laser joining are mixed.

  The remaining laser light L that has passed through the first laser light absorption layer 31 of the intermediate member 3 for laser bonding passes through the laser light transmission layer 33 and reaches the second laser light absorption layer 32. Since the second laser light absorption layer 32 has a laser light absorption rate of 20% or more, 20% or more of the remaining laser light L is absorbed by the second laser light absorption layer 32. Thereby, the surface located in the intermediate member 3 for laser joining in the 2nd member 2 fuse | melts. Then, the resin of the second member 2 and the resin of the intermediate member 3 for laser bonding are mixed.

  Here, description will be made on the result of the joining test conducted by the inventors changing the laser light absorption rate of the first laser light absorption layer 31 and the laser light absorption rate of the second laser light absorption layer 32 to various values. To do.

  When the laser light absorption rate of the first laser light absorption layer 31 is set to a value smaller than 20%, heat generation on the first member 1 side is not sufficient, and the bonding strength between the laser bonding intermediate member 3 and the first member 1 is low. Not enough.

  Further, when the laser light absorption rate of the second laser light absorption layer 32 is set to a value smaller than 20%, heat generation on the second member 2 side is not sufficient, and the joining between the laser joining intermediate member 3 and the second member 2 is performed. Insufficient strength is obtained.

  That is, in this embodiment, the first laser light absorption layer 31 and the second laser light absorption layer 32 have a laser light absorption rate of 20% or more, so that heat generation on the first member 1 side in the intermediate member 3 for laser bonding is achieved. It is possible to reduce the difference between the amount of heat and the amount of heat generated on the second member 2 on the side of the intermediate member 3 for laser bonding, so that the amount of heat generated by both can be well balanced. Thereby, it is possible to melt both the first member 1 side and the second member 2 side of the intermediate member 3 for laser bonding.

  The laser light absorption rate of the first laser light absorption layer 31 and the second laser light absorption layer 32 is preferably 20% or more and 50% or less.

  When the resin is solidified by cooling after irradiation with the laser beam L, a joined product A in which the first member 1 and the second member 2 are joined via the intermediate member 3 for laser joining is obtained.

  As described above, according to this embodiment, the intermediate member 30 for laser bonding includes the first laser light absorption layer 31 formed on the first member 1 side and the second laser beam formed on the second member 2 side. The laser light absorption layer 32 and the laser light transmission layer 33 formed between the laser light absorption layers 31 and 32 are provided, and the laser light absorption rate of the first laser light absorption layer 31 is set to 20% or more. The laser light absorption rate of the second laser light absorption layer 32 was set to 20% or more. Thereby, since both the 1st member 1 side and the 2nd member 2 side of the intermediate member 30 for laser joining can be fuse | melted moderately, the joining strength of the 1st member 1 and the 2nd member 2 is fully raised. Can do.

  In the embodiment, the second member 2 may have a laser light absorption property or may have a laser light transmission property. Examples of those that do not have laser light absorption include metal materials, metal oxides, and colored resin materials. Examples of metals include stainless steel, aluminum alloy, and magnesium alloy.

  In the embodiment, the upper limit of the laser light absorption rate of the first laser light absorption layer 31 and the second laser light absorption layer 32 is preferably 50%.

  Further, when the laser light absorption rate of the first laser light absorption layer 31 is 35% and the laser light absorption rate of the second laser light absorption layer 32 is 40%, the laser light absorption of the entire intermediate member 3 for laser bonding is absorbed. The rate is 61%.

  Further, when the laser light absorption rate of the first laser light absorption layer 31 is 40% and the laser light absorption rate of the second laser light absorption layer 32 is 40%, the laser light absorption of the entire intermediate member 3 for laser bonding is absorbed. The rate is 64%.

  Further, when the laser light absorption rate of the first laser light absorption layer 31 is 20% and the laser light absorption rate of the second laser light absorption layer 32 is 50%, the laser light absorption of the entire intermediate member 3 for laser bonding is absorbed. The rate will be 60%.

  Since the laser light L incident on the second laser light absorption layer 32 is attenuated by the first laser light absorption layer 31, the laser absorption rate of the second laser light absorption layer 32 is changed to the laser of the first laser light absorption layer 31. It is preferable to increase the absorption rate.

  In the embodiment, at the time of bonding, the laser beam L having such an intensity that the intermediate member 3 for laser bonding is softened may be irradiated.

  The thicknesses of the first laser light absorption layer 31 and the second laser light absorption layer 32 may be the same as or different from each other, and the shape and plane of the first member 1 and the second member 2 It can be set arbitrarily depending on the accuracy.

  The materials and melting temperatures of the first laser light absorption layer 31 and the second laser light absorption layer 32 may be determined so as to match the materials of the first member 1 and the second member 2. Therefore, the first laser light absorption layer 31 and the second laser light absorption layer 32 may be made of completely different materials. Further, the material of the laser light transmission layer 33 may be any material as long as adhesion with the first laser light absorption layer 31 and the second laser light absorption layer 32 is obtained. Further, in order to improve the adhesion between the first laser light absorption layer 31 and the second laser light absorption layer 32, the material constituting the laser light transmission layer 33 may be subjected to surface treatment by corona discharge or application of a primer. Good.

  The present invention can also be applied to devices other than home appliances and house equipment.

  Examples according to the embodiments of the present invention will be described below.

(Reference example)
The first member 1 is a colorless and transparent polycarbonate plate (manufactured by Mitsubishi Plastics, Inc.). The length of the first member 1 is 75 mm, the width is 25 mm, and the thickness is 2 mm.

  The second member 2 is a black polycarbonate plate (manufactured by Mitsubishi Engineering Plastics). The length, width, and thickness of the second member 2 are the same as those of the first member 1. The laser light absorption rate of the second member 2 is 60% or more.

  The laser joining intermediate member 3 is composed of an acrylic thermoplastic elastomer (product number LA2140E manufactured by Kuraray Co., Ltd.) and carbon black. The amount of carbon black added is 0.0015 parts by weight. The carbon black and the elastomer were sufficiently kneaded using a resin kneading roll to obtain a laser light absorbing resin. This laser light absorbing resin was sandwiched between two Teflon sheets and pressed with a hot platen to obtain a laser bonding intermediate member 3 having a thickness of 500 μm.

  The laser absorptivity of the intermediate member 3 for laser bonding thus obtained was 50% at an absorption wavelength of 940 nm.

  After the laser joining intermediate member 3 was cut into a ribbon shape having a width of 5 mm, it was placed on the joining surface of the second member 2 across both ends of the second member 2 in the short side direction (see FIG. 5A). Then, the first member 1 was stacked on the joint surface of the second member 2. At this time, the vicinity of the short side of the first member 1 and the vicinity of the short side of the second member 2 are overlapped (see FIG. 5B).

  The first member 1 and the second member 2 are clamped with a clamping pressure of 0.4 MPa using a clamping jig.

  Thereafter, a semiconductor laser beam L having a wavelength of 940 nm was irradiated from the first member 1 side along the intermediate member 3 for laser bonding at an output of 30 W at a scanning speed of 1.2 m / min.

  After irradiation with the laser beam L, the first and second members 1 and 2 were cooled to room temperature, and then the bonding strength was measured. The bonding strength was measured by applying a tensile force to the first member 1 and the second member 2 in the shearing direction and in a direction perpendicular to the scanning direction of the laser beam L. The tensile speed is 5 mm / min.

  As a result, the first member 1 peeled from the second member 2 when a tensile force of 1500 N was applied. The cause of peeling was cohesive failure of the intermediate member 3 for laser bonding. That is, the bonding strength between the first member 1 and the second member 2 was practically sufficient.

  Further, the first member 1 and the second member 2 were not burnt or decomposed.

(Example)
In the embodiment, the first member 1 and the second member 2 are both colorless and transparent polycarbonate plates (manufactured by Mitsubishi Plastics, Inc.), have a length of 75 mm, a width of 25 mm, and a thickness of 2 mm.

  The intermediate member 3 for laser bonding has the three-layer structure described in the above embodiment. That is, as shown in FIG. 4, the first laser light absorption layer 31, the second laser light absorption layer 32, and the laser light transmission layer 33 are provided.

  The first laser light absorption layer 31 and the second laser light absorption layer 32 are the same, and are composed of an acrylic thermoplastic elastomer and carbon black. The amount of carbon black added is 0.0033 parts by weight. The elastomer and carbon black were dispersed and dissolved in toluene to obtain 45 parts by weight of a resin solution.

  The resin solution was applied on both sides of an acrylic film (Acryprene HBS027 manufactured by Mitsubishi Rayon Co., Ltd.) and dried. The acrylic film corresponds to the laser light transmission layer 33 of the intermediate member 3 for laser bonding. The resin solution was dried, and the first laser light absorption layer 31 and the second laser light absorption layer 32 were formed on both surfaces of the laser light transmission layer 33. The first laser light absorption layer 31 and the second laser light absorption layer 32 have the same thickness and are 100 μm.

  The laser light absorption rates of the first laser light absorption layer 31 and the second laser light absorption layer 32 were both 25%. The laser light absorptance of the entire laser bonding intermediate member 3 was 44%.

  Similarly to the reference example, the laser joining intermediate member 3 was clamped by being sandwiched between the first member 1 and the second member 2, and then the laser beam L was irradiated. The irradiation conditions of the laser beam L are the same as in the reference example.

  The bonding strength of the example was measured and found to be 1600 N, which was practically sufficient.

  Further, the first member 1 and the second member 2 were not burnt or decomposed.

  Next, a comparative example will be described.

(Comparative Example 1)
An intermediate member 3 for laser bonding was obtained in the same manner as in the reference example. However, the amount of carbon black added was 0.0007 parts by weight, and the laser light absorption rate was 30% under the above conditions. The first member 1 and the second member 2 of Comparative Example 1 are the same as the reference example.

  Similarly to the reference example, the laser joining intermediate member 3 was clamped by being sandwiched between the first member 1 and the second member 2, and then the laser beam L was irradiated under the same conditions as in the reference example.

  The joint strength of Comparative Example 1 was measured to be 100 N, and the first member 1 was easily peeled from the second member 2. Further, the second member 2 was burnt and deteriorated.

  This is because the laser transmittance of the laser joining intermediate member 3 is too high, the first member 1 side of the laser joining intermediate member 3 generates less heat, and the melting of the first member 1 and the laser joining intermediate member 3 is insufficient. On the contrary, on the second member 2 side of the intermediate member 3 for laser bonding, the heat generation is too large and the second member 2 is thermally deteriorated.

(Comparative Example 2)
An intermediate member 3 for laser bonding was obtained in the same manner as in the reference example. However, the amount of carbon black added was 0.0023 parts by weight, and the laser light absorption was 70% under the above conditions. The first member 1 and the second member 2 of Comparative Example 1 are the same as the reference example.

  Similarly to the reference example, the laser joining intermediate member 3 was clamped by being sandwiched between the first member 1 and the second member 2, and then the laser beam L was irradiated under the same conditions as in Example 1.

  The joint strength of Comparative Example 2 was measured to be 80 N, and the first member 1 was easily peeled from the second member 2. Further, the first member 1 was burnt and deteriorated.

  This is because the laser absorptivity of the laser joining intermediate member 3 is too high, and the first member 1 side of the laser joining intermediate member 3 generates too much heat, and the first member 1 and the laser joining intermediate member 3 are heated. On the contrary, on the second member 2 side of the intermediate member 3 for laser bonding, heat generation is insufficient and melting of the intermediate member 3 for laser bonding and the second member 2 is insufficient.

(Comparative Example 3)
In the same manner as in the example, an intermediate member 3 for laser bonding was obtained. However, the addition amount of carbon black was 0.0016 parts by weight, and the laser light absorption rates of the first laser light absorption layer 31 and the second laser light absorption layer 32 were 15% under the above conditions. The laser beam absorptance of the entire laser joining intermediate member 3 was 28%.

  The 1st member 1 and the 2nd member 2 of comparative example 3 are the same as an example.

  Similarly to the example, the laser joining intermediate member 3 was clamped by being sandwiched between the first member 1 and the second member 2, and then the laser beam L was irradiated under the same conditions as in the example.

  The joint strength of Comparative Example 3 was measured to be 100 N, and the first member 1 was easily peeled from the second member 2.

  This is because the laser transmittance of the intermediate member 3 for laser bonding is too high, the heat generation of the intermediate member 3 for laser bonding is insufficient, and the first laser light absorption layer 31 and the second laser light absorption layer 32 are sufficiently melted. Due to not.

(Comparative Example 4)
In the same manner as in the example, an intermediate member 3 for laser bonding was obtained. However, the addition amount of carbon black in the first laser light absorption layer 31 was 0.0102 parts by weight, and the addition amount of carbon black in the second laser light absorption layer 32 was 0.0016 parts by weight.

  The laser light absorption rate of the first laser light absorption layer 31 was 40% under the above conditions. The laser light absorption rate of the second laser light absorption layer 32 was 15% under the above conditions. The laser beam absorptance of the entire laser joining intermediate member 3 was 49%.

  The 1st member 1 and the 2nd member 2 of comparative example 4 are the same as an example.

  Similarly to the example, the laser joining intermediate member 3 was clamped by being sandwiched between the first member 1 and the second member 2, and then the laser beam L was irradiated under the same conditions as in the example.

  When the bonding strength of Comparative Example 4 was measured, it was 120 N, and the second member 2 was easily peeled off from the interface of the second laser light absorption layer 32.

  This is because the laser absorptivity of the first laser light absorption layer 31 of the intermediate member 3 for laser bonding is too high, and the sufficient laser light L does not reach the second laser light absorption layer 32, and the second laser light absorption. This is because the laser absorptivity of the layer 32 is too low and the second laser light absorption layer 32 does not sufficiently generate heat and is insufficiently melted.

(Comparative Example 5)
In the same manner as in the example, an intermediate member 3 for laser bonding was obtained. However, the addition amount of carbon black in the first laser light absorption layer 31 was 0.0016 parts by weight, and the addition amount of carbon black in the second laser light absorption layer 32 was 0.0102 parts by weight.

  The laser light absorption rate of the first laser light absorption layer 31 was 15% under the above conditions. The laser light absorption rate of the second laser light absorption layer 32 was 40% under the above conditions. The laser beam absorptance of the entire laser joining intermediate member 3 was 49%.

  The first member 1 and the second member 2 of Comparative Example 5 are the same as in the example.

  Similarly to the example, the laser joining intermediate member 3 was clamped by being sandwiched between the first member 1 and the second member 2, and then the laser beam L was irradiated under the same conditions as in the example.

  The bonding strength of Comparative Example 5 was 90 N, and the first member 1 was easily peeled from the interface of the first laser light absorption layer 31.

  This is because the laser transmittance of the first laser light absorption layer 31 of the intermediate member 3 for laser bonding is too high, and the laser light L is almost transmitted, the first laser light absorption layer 31 generates little heat, and is sufficiently melted. Due to not doing.

(Comparative Example 6)
In the same manner as in the example, an intermediate member 3 for laser bonding was obtained. However, the amount of carbon black added was 0.0102 parts by weight, and the laser light absorption rates of the first laser light absorption layer 31 and the second laser light absorption layer 32 were 40% under the above conditions. The laser beam absorptance of the entire laser joining intermediate member 3 was 64%.

  The 1st member 1 and the 2nd member 2 of comparative example 6 are the same as an example.

  Similarly to the example, the laser joining intermediate member 3 was clamped by being sandwiched between the first member 1 and the second member 2, and then the laser beam L was irradiated under the same conditions as in the example.

  When the bonding strength of Comparative Example 6 was measured, it was 200 N, and the second member 2 was easily peeled from the interface of the second laser light absorption layer 32.

  This is because the laser absorption rate of the first laser light absorption layer 31 of the intermediate member 3 for laser bonding is too high, and the laser light L reaching the second laser light absorption layer 32 is not sufficient. This is due to the fact that there was little heat generation and it did not melt sufficiently.

  As explained above, the joining method using laser light and the intermediate member for laser joining according to the present invention can be used, for example, at the manufacturing site of home appliances, housing equipment and the like.

DESCRIPTION OF SYMBOLS 1 1st member 2 2nd member 3 and 30 Intermediate member 31 for laser joining 1st laser light absorption layer 32 2nd laser light absorption layer 33 Laser light transmission layer A Joining article L Laser light

Claims (2)

An intermediate member for laser bonding having laser light absorptivity is interposed between a first member having laser light transmissivity and a second member having laser light transmissivity or laser light absorptivity, and the first member and In the joining method using laser light for joining the second member with the intermediate member for laser joining,
The intermediate member for laser joining is formed on the first member side and has a first laser light absorption layer having laser light absorption, and a second laser light is formed on the second member side and has laser light absorption. An absorption layer, and a colorless and transparent laser light transmission layer formed between the first laser light absorption layer and the second laser light absorption layer and having a laser light transmittance of a wavelength of 940 nm ,
The first laser light absorption layer and the second laser light absorption layer are made of an organic dye, an organic pigment, and carbon black in an elastomer selected from the group consisting of a styrene elastomer, a polyester elastomer, a urethane elastomer, and an acrylic elastomer. A laser light absorber selected from the group consisting of:
The laser light transmission layer is made of a resin selected from the group consisting of polypropylene, polyethylene, polycarbonate, polybutene, vinyl chloride, polyacetal, polyethylene terephthalate and acrylic resin,
The laser light absorptance of the entire laser bonding intermediate member at a wavelength of 940 nm is set to 40% or more and 60% or less, and the laser light absorptance of the first laser light absorption layer at a wavelength of 940 nm is set to 20% or more. The laser light absorption rate at a wavelength of 940 nm of the second laser light absorption layer is set to 20% or more,
Thereafter, the first member, the intermediate member for laser bonding, and the second member are overlaid with the intermediate member for laser bonding interposed between the first member and the second member,
Then, the joining method using the laser beam which irradiates a laser beam from the said 1st member side. A first member having laser beam transparency and a second member having laser beam transparency or laser beam absorption property are formed so as to be interposed between the first member and the second member. In the intermediate member for laser bonding,
A first laser light absorbing layer formed on the first member side and having a laser light absorption property;
A second laser light absorption layer formed on the second member side and having laser light absorption;
A colorless and transparent laser light transmission layer formed between the first laser light absorption layer and the second laser light absorption layer and having a laser light transmittance of 940 nm ;
The first laser light absorption layer and the second laser light absorption layer are made of an organic dye, an organic pigment, and carbon black in an elastomer selected from the group consisting of a styrene elastomer, a polyester elastomer, a urethane elastomer, and an acrylic elastomer. A laser light absorber selected from the group consisting of:
The laser light transmission layer is made of a resin selected from the group consisting of polypropylene, polyethylene, polycarbonate, polybutene, vinyl chloride, polyacetal, polyethylene terephthalate and acrylic resin,
The total laser light absorption rate of the first laser light absorption layer, the second laser light absorption layer, and the laser light transmission layer is set to 40% or more and 60% or less when irradiated with laser light having a wavelength of 940 nm,
The laser light absorption rate of the first laser light absorption layer is set to 20% or more when irradiated with laser light having a wavelength of 940 nm,
An intermediate member for laser bonding, wherein the second laser light absorption layer has a laser light absorption rate of 20% or more when irradiated with laser light having a wavelength of 940 nm.

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