JP2013173322A - Intermediate member for laser bonding and bonding method using laser beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable members having high thermal conductivity to be efficiently bonded to each other and to stably obtain high bonding strength.SOLUTION: There is provided an intermediate member 1 for laser bonding which is arranged between a first member 10 having laser beam transmissive property and a second member 20 having a thermal conductivity higher than that of the first member 10 upon bonding both members 10, 20 to each other using laser beam. The intermediate member 1 is composed of a resin material melting with the irradiation of the laser beam and is set to have ≥300 μm thickness.

Description

  The present invention relates to a laser joining intermediate member used when joining various members using laser light and a joining method using laser light.

  For example, home appliances, housing products, office supplies, toys, etc. have parts that require high strength and unnecessary parts, and metal parts are used for parts that require high strength, while unnecessary parts A resin material is often used for the. Similarly, in industrial equipment and industrial facilities, there are portions that require high strength and portions that do not need to be used, and therefore metal materials and resin materials are selectively used as necessary.

  In addition, electrical appliances such as computers and home appliances may incorporate components that serve as heat sources such as motors and light sources, and components that have heat such as ICs and integrated circuits. A metal material having high thermal conductivity is used for heat radiation of these components. In addition to metal materials, parts made of resin materials are also used in electrical appliances.

  Furthermore, for example, in automobiles, there is a strong demand for reducing energy consumption and improving fuel consumption, and for this reason, development of weight reduction of the vehicle body is being promoted as the most important theme. In order to reduce the weight of the vehicle body, the use of a resin material is effective, and attempts have been made to convert each component, which has been a metal material, into a resin. However, there are places where metal materials are inevitably used due to problems in strength, heat dissipation, and the like, and metal materials and resin materials are selectively used as necessary.

  As described above, a metal material and a resin material are used properly in each field, and naturally, in such a situation, there is a demand for joining the metal material and the resin material. Generally, fastening with bolts or the like, caulking, an adhesive, an adhesive, or the like may be used. Bolts and caulking have problems that each part needs to be processed, fasteners are required, which is troublesome and heavy, and that it is difficult to stably obtain high joint strength with adhesives and adhesives. there were.

  As means for solving these problems, for example, a joining method using a laser beam has been devised (see, for example, Patent Documents 1 to 3).

  In Patent Document 1, when a thermoplastic resin material and a metal material are joined, a thermoplastic film compatible with the thermoplastic resin material is interposed at the joining interface, and a laser beam is irradiated in this state to form a metal. The material is heated, and the film is melted by the heat of the metal material to join the thermoplastic resin material and the metal material.

  In Patent Document 2, laser light is irradiated from the thermoplastic resin material side in a state in which the thermoplastic resin material and the metal material are overlapped to join the thermoplastic resin material and the metal material.

  In Patent Document 3, when a resin material and a metal material are bonded, the bonding interface between the resin material and the metal material is heated to a temperature higher than the decomposition temperature of the resin material and lower than a temperature at which bubbles are generated in the resin material. I have to.

JP 2009-39987 A JP 2008-207547 A JP 2010-46831 A

  However, even when a laser beam is irradiated when joining a thermoplastic resin material and a metal material as in Patent Documents 1 to 3, the heat conductivity of the metal material is significantly higher than that of the resin material. The heat generated by the irradiation of the metal is quickly transferred to the parts other than the joint part of the metal material, and it takes a lot of energy to heat the metal material to a temperature at which the resin material can be melted. There's a problem. In particular, if the metal material is a metal material with high thermal conductivity such as aluminum alloy, copper, brass, etc., and the volume is large, the metal material only generates heat even when irradiated with laser light. It is difficult to melt the material.

  Also, for example, when using a laser beam joining method in electrical appliances or automobiles, when an IC or computer is first installed, the heat of the metal material generated by the laser beam irradiation is transferred to those parts. May cause damage. In particular, when a metal material is used as a heat radiating member such as an IC, this problem becomes significant when the metal material and the resin material are joined.

  In Patent Document 3, the resin material is heated to the decomposition temperature or higher, but the physical characteristics of the resin material heated to the decomposition temperature or higher are deteriorated. Strength cannot be expected. Moreover, since the resin material has decomposed | disassembled, there also exists a problem of becoming weak.

  This invention is made | formed in view of this point, The place made into the objective makes it possible to join a high thermal conductivity member and a low member efficiently, and to obtain high joint strength stably. Is to be able to.

  In order to achieve the above object, in the present invention, heat generated by laser light irradiation is prevented from being transmitted to a member having high thermal conductivity.

  1st invention is arrange | positioned between both members, when joining the 1st member which has laser-light transmittance, and the 2nd member whose heat conductivity is higher than this 1st member using a laser beam. The intermediate member for laser bonding is made of a resin material that melts when irradiated with the laser beam, and has a thickness of 300 μm or more.

  According to this configuration, when heat is generated by irradiating laser light from the first member side, the intermediate member for laser bonding has a thickness of 300 μm or more, so that the intermediate member for laser bonding has a heat insulating effect. It is possible to sufficiently suppress the heat transfer to the second member having a high thermal conductivity. Thereby, the energy loss of the laser beam is reduced, the intermediate member for laser bonding is efficiently melted, and high bonding strength can be stably obtained.

  In addition, since the amount of heat transmitted to the second member is suppressed, even if a heat-sensitive component such as an IC or a computer is incorporated in advance on the second member side, it is not necessary to cause thermal damage to the component. .

  In addition, when the laser joining intermediate member is thinner than 300 μm, the heat insulation effect is reduced and the heat generated by the laser light irradiation is easily transferred to the second member, and the laser joining intermediate member is melted. Since it becomes difficult, it becomes impossible to join the 1st member and the 2nd member firmly.

According to a second invention, in the first invention,
It contains a laser light absorber, and the laser light absorption rate is set to 40% or more.

  According to this configuration, the laser beam irradiated from the first member side is efficiently converted into heat in the intermediate member for laser bonding, and the intermediate member for laser bonding is sufficiently melted on the interface side with the first member by the heat. It becomes possible to make it.

  A third invention is characterized in that in the first or second invention, a thermoplastic elastomer is contained.

  According to this configuration, since the flexibility of the intermediate member for laser bonding is increased, the peeling force acting between both members can be changed even if the temperature is changed when the thermal expansion coefficients of the first member and the second member are different. Absorption can be achieved by deformation of the joining intermediate member.

According to a fourth aspect of the present invention, an intermediate member for laser bonding is disposed between a first member having laser light permeability and a second member having a higher thermal conductivity than the first member, and the first member and In the bonding method using laser light for bonding the second member,
Bonding the intermediate member for laser bonding set to a thickness of 300 μm or more to the second member;
Thereafter, the first member is disposed on the opposite side of the intermediate member for laser bonding to the second member, and laser light is irradiated from the first member side to melt the intermediate member for laser bonding,
Thereafter, the intermediate member for laser bonding is cooled.

  According to this configuration, since the intermediate member for laser bonding exhibits a sufficient heat insulation effect, energy loss of the laser beam is reduced, and the intermediate member for laser bonding is efficiently melted to stably obtain high bonding strength. .

In a fourth aspect based on the fourth aspect, the heat transfer coefficient of the first member is set to 0.1 or more and 1.0 W · m ⁻¹ · K ⁻¹ or less,
The heat transfer coefficient of the second member is set to 100 W · m ⁻¹ · K ⁻¹ or more.

  According to this configuration, when the difference in heat transfer coefficient between the first member and the second member is large, the heat insulating effect of the intermediate member for laser bonding becomes even more remarkable, and the first member and the second member are It becomes possible to join reliably.

  According to the first invention, since the thickness of the intermediate member for laser bonding disposed between the first member having laser light permeability and the second member having high thermal conductivity is set to 300 μm or more, the first When heat is generated by irradiating laser light from the member side, the intermediate member for laser bonding exhibits a sufficient heat insulating effect, and heat transfer to the second member can be suppressed. Thereby, while being able to join a member with high heat conductivity efficiently, high joint strength can be obtained stably.

  According to the second invention, since the laser beam absorptance of the intermediate member for laser bonding is set to 40% or more, the intermediate member for laser bonding can be sufficiently melted in the vicinity of the interface on the first member side. Thereby, the joint strength between the first member and the second member can be further increased.

  According to the third invention, since the intermediate member for laser joining contains the thermoplastic elastomer, the peeling force acting between the first member and the second member when the temperature is changed after joining is laser joined. It can be absorbed by deformation of the intermediate member for use, and therefore, high bonding strength can be stably obtained even when the temperature changes.

  According to the fourth invention, the same effect as that of the first invention can be obtained.

  According to the fifth aspect, when the difference in heat transfer coefficient between the first member and the second member is large, the heat insulating effect of the intermediate member for laser bonding becomes even more remarkable, and the first member and the second member Can be reliably joined.

It is a perspective view showing the state where the 1st member and the 2nd member were joined using the intermediate member for laser joining concerning an embodiment. It is explanatory drawing of the joining method using the laser beam concerning embodiment.

  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.

  FIG. 1 is a perspective view showing a state in which a first member 10 and a second member 20 are joined using a laser joining intermediate member 1 according to an embodiment of the present invention.

  The first member 10 is a plate material made of a thermoplastic resin material. Examples of the thermoplastic resin material include polyethylene (HDPE, LDPE, LLDPE, VLDPE, ULDPE, UHDPE, Polyethylene), polypropylene (PP Co-Polymer, PP Homo-Polymer, PP Ter-Polymer), polyvinyl chloride (PVC), Polystyrene (PS), polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene resin (ABS), styrene acrylonitrile resin (SAN), K-resin, SBS resin (SBS block co-polymer), PVDC resin, EVA resin, Acrylic resin, butyral resin, silicone resin, polyamide (PA, PA6, PA66, PA46, PA610, PA612, PA6 / 66, PA6 / 12, PA6T, PA12, PA1212, PAMXD6), ethylenetetrafluoroethylene copolymer, liquid crystal polymer , Polybutylene terephthalate, Polyether ether ketone, Polyether ketone, Polyether ketone ketone, Polyethylene naphthalene, Polyethylene terephthalate, Poly Examples include imide, polyacetal, polyamideimide, polyphenylene ether, polyphenylene oxide, polycarbonate, polyphenylene sulfide, polysulfone, polythioethylsulfone, polytetrafluoroethylene, polyethersulfone, and polyetherimide.

In addition, it includes modified resins in which polar functional groups are chemically bonded. Specifically, acrylic acid-modified olefin resins, maleic acid-modified olefin resins, chloride-modified olefin resins (CPP, CPE), silane-modified olefin resins, ionomer resins. , Nylon-modified olefin resin, epoxy-modified resin, ethylene vinyl alcohol resin (EVOH), ethylene vinyl acetate resin, hot melt adhesive resin, and the like, and may be a mixture or combination of these and the above thermoplastic resins. However, it is not limited to these. The thermal conductivity of the resin material constituting the first member 10 is set to 0.1 or more and 1.0 W · m ⁻¹ · K ⁻¹ or less.

  The first member 10 has laser beam transparency. Laser light transmission means that laser light is transmitted with almost no reflection or absorption, but the remaining laser light can be transmitted without melting even if a part of the laser light is transmitted and / or reflected. This includes properties that transmit all of the laser light. Further, the laser transmittance of the first member 10 may be such that a part of the first member 10 is melted. In this embodiment, the first member 10 is colorless and transparent, but may be colored.

The 2nd member 20 is a board | plate material comprised with the metal material with high heat conductivity. Examples of the metal material include, but are not limited to, an aluminum alloy, copper, and brass. The thermal conductivity of the metal material constituting the second member 20 is set to 100 W · m ⁻¹ · K ⁻¹ or more, and the upper limit is, for example, 450 W · m ⁻¹ · K ⁻¹ .

  Further, the second member 20 is subjected to chemical surface treatment or physical surface treatment for further strengthening the bonding strength with the laser bonding intermediate member 1, and these surface treatments are performed as necessary. May be omitted, and may be omitted.

  Examples of the chemical surface treatment include a treatment performed using a primer, an acid or alkali treatment, a coupling agent, an isocyanate, and the like.

  As the physical surface treatment, there are anodizing treatment and treatment using the anchor effect by providing fine irregularities. Chemical surface treatment and physical surface treatment may be combined. By performing these surface treatments on the second member 20, the laser bonding intermediate member 1 can be firmly bonded to the second member 20.

  As a method for joining the laser joining intermediate member 1 to the second member 20, for example, ultrasonic welding or vibration welding, or a method of supplying the raw material of the laser joining intermediate member 1 into a mold for molding the second member 20 is used. The simultaneous molding to be joined to the two members 20, heat fusion, and the like can be mentioned, but the invention is not limited to these.

  Moreover, when assembling electronic parts, such as IC and a computer, to the 2nd member 20, it is preferable to join the intermediate member 1 for laser joining, before assembling these electronic parts.

  The material of the intermediate member 1 for laser joining is a thermoplastic resin material containing a laser light absorbent and a thermoplastic elastomer. As the thermoplastic resin material that is the main component of the intermediate member 1 for laser bonding, a resin material that is highly compatible with the resin material that constitutes the first member 10 is preferable, and even the resin material that constitutes the first member 10. Good. The most preferable resin material constituting the intermediate member 1 for laser bonding is to mix with the resin material forming the first member 10 when bonded to the first member 10 and to maintain the mixed state after cooling. It is a resin material that can be used. By using such a resin material, it is possible to obtain high bonding strength.

  Examples of the laser light absorber include organic dyes, organic pigments, metal oxides, commercially available laser light absorbers, carbon black, and the like. The laser light absorbing agent absorbs the laser light and sufficiently generates heat. What is necessary is just what can be made to be, and it is not restricted to the above-mentioned thing.

  The laser beam absorptivity of the intermediate member 1 for laser bonding can be arbitrarily set according to the type and blending amount of the laser beam absorber. In this embodiment, the laser beam absorptivity of the laser bonding intermediate member 1 is set to 40% or more, preferably 50% or more, more preferably 60% or more.

  If the laser beam absorptivity of the laser joining intermediate member 1 is lower than 40%, the laser joining intermediate member 1 cannot absorb the laser light effectively, and the laser joining intermediate member 1 is sufficiently heated to generate the first member. 10 may not be melted together.

  When the laser beam absorptivity of the laser bonding intermediate member 1 is 60% or more, the laser bonding intermediate member 1 can effectively absorb the laser beam, and the laser bonding intermediate member 1 can sufficiently generate heat. It becomes possible. As a result, as will be described later, the first member 10 side of the intermediate member 1 for laser bonding can be melted, the first member 10 can also be melted, and both resins can be mixed.

  The thermoplastic elastomer is not particularly limited as long as it exhibits rubber elasticity near room temperature, and examples thereof include styrene, acrylic, polyester, olefin, urethane, nylon, and the like. It is preferable to contain the first member 10 so as not to cause a decrease in bonding strength.

  The thermoplastic elastomer content is 10% by weight or more of the intermediate member 1 for laser joining, preferably 20% by weight or more, more preferably 30% by weight or more. Therefore, the present invention is not limited to this range.

  By including the thermoplastic elastomer in the laser joining intermediate member 1, flexibility can be imparted to the laser joining intermediate member 1. As a result, even if the first member 10 and the second member 20 have different coefficients of thermal expansion, the peeling force acting between the members 10 and 20 is absorbed by the deformation of the intermediate member 1 for laser bonding even if the temperature is changed. It becomes possible.

  The thickness of the intermediate member 1 for laser bonding may be a thickness that can suppress transmission of heat generated during laser light irradiation, which will be described later, to the second member 20, and is set to 300 μm or more. ing. If the thickness of the intermediate member 1 for laser bonding is less than 300 μm, the heat insulating effect is low, and heat generated by laser light irradiation is easily transferred to the second member 20, and the intermediate member 1 for laser bonding is melted. Since it becomes difficult, the 1st member 10 and the 2nd member 20 cannot be joined firmly.

  The thickness of the intermediate member 1 for laser bonding is preferably 500 μm or more, more preferably 700 μm or more. By setting the thickness of the intermediate member 1 for laser bonding to 700 μm or more, it becomes easier to focus the laser beam on the interface between the first member 10 and the intermediate member 1 for laser bonding. It becomes possible to heat the member 10 side reliably. Furthermore, the second member 20 side sufficiently exhibits a role as a heat insulating material from the interface with the first member 10 of the intermediate member 1 for laser bonding, and thereby the first member 10 side of the intermediate member 1 for laser bonding is sufficiently provided. Can be melted.

  Next, the procedure for joining the first member 10 and the second member 20 using the intermediate member 1 for laser joining will be described.

  In this embodiment, an electronic component that is weak against heat is assembled to the second member 20, and the first member 10 is joined to the second member 20 via the laser joining intermediate member 1.

  First, the laser joining intermediate member 1 is joined to the second member 20 on which no electronic component is assembled. At this time, ultrasonic welding, vibration welding, simultaneous molding, thermal fusion, or the like is used. Since the electronic component is not yet assembled to the second member 20, there is no influence even if the second member 20 is vibrated or heated.

  Thereafter, the electronic component is assembled to the second member 20.

  Thereafter, the first member 10 is placed on the second member 20 side of the intermediate member 1 for laser bonding, and clamped (pressed) in the thickness direction using a clamping device or the like (not shown). The applied pressure is preferably, for example, 5N or more, more preferably 10N or more. Thereby, the 1st member 10 and the intermediate member 1 for laser joining can fully be stuck.

  Next, as shown in FIG. 2, the laser beam L is irradiated from the first member 10 side toward the intermediate member 1 for laser bonding. The focal point of the laser beam L is set near the interface on the first member 10 side of the intermediate member 1 for laser bonding. Although the kind of laser beam L is not specifically limited, For example, a gas laser, a solid state laser, a semiconductor laser, a fiber laser etc. can be utilized. The wavelength of the laser beam L is preferably in the range of 800 nm to 1500 nm.

  When the laser beam is irradiated, since the focal point is set in the vicinity of the interface on the first member 10 side of the intermediate member 1 for laser bonding, the first member 10 side of the intermediate member 1 for laser bonding mainly absorbs the laser beam. Fever. At this time, since the laser light absorptance is set to 40% or more, the intermediate member 1 for laser bonding can be efficiently heated.

  Since the thickness of the intermediate member 1 for laser bonding is 300 μm or more, when the first member 10 side of the intermediate member 1 for laser bonding is heated, the second member 20 side of the intermediate member 1 for laser bonding functions as a heat insulating material, Demonstrate the heat insulation effect sufficiently. Thereby, it becomes possible to suppress heat from being transmitted to the second member 20 having a high thermal conductivity, the temperature of the intermediate member 1 for laser bonding can be increased and melted, and the first member 10 is also Can be melted. When the laser joining intermediate member 1 and the first member 10 are melted, the resin constituting the laser joining intermediate member 1 and the resin constituting the first member 10 are mixed.

  Moreover, since it can suppress by the intermediate member 1 for laser joining that heat is transmitted to the 2nd member 20 as mentioned above, the heating of the electronic component assembled | attached to the 2nd member 20 is suppressed, and an electronic component Damage due to heat can be prevented.

  Then, the melted portions of the laser bonding intermediate member 1 and the first member 10 are allowed to stand for a predetermined time to be cooled and solidified. Thereafter, when the clamping device is removed, the first member 10 and the second member 20 are joined by the intermediate member 1 for laser joining.

  As described above, according to this embodiment, the thickness of the intermediate member 1 for laser bonding disposed between the first member 10 having laser light permeability and the second member 20 having high thermal conductivity is set. Since the heat is generated by irradiating the laser beam from the first member 10 side because the thickness is 300 μm or more, the intermediate member 1 for laser bonding exhibits a sufficient heat insulating effect, and heat is transmitted to the second member 20. Can be suppressed. Thereby, while being able to join a member with high heat conductivity efficiently, high joint strength can be obtained stably.

  Since the laser beam absorptivity of the laser bonding intermediate member 1 is 40% or more, the laser bonding intermediate member 1 can be sufficiently melted in the vicinity of the interface on the first member 10 side. Thereby, the joint strength between the first member 10 and the second member 20 can be further increased.

  In addition, since the laser joining intermediate member 1 contains a thermoplastic elastomer, the peeling force that acts between the first member 10 and the second member 20 when a temperature change is applied after joining is provided. Therefore, even when the temperature changes, a high bonding strength can be stably obtained. Further, when watertightness or airtightness is required between the first member 10 and the second member 20, the first member 10 and the second member since the intermediate member 1 for laser bonding has flexibility. Therefore, it can be deformed along the members 10 and 20 to function as a sealing material, and sufficient water tightness and air tightness can be obtained.

  The present invention can also be applied to the case where an electronic component or the like is not assembled to the second member 20. Further, when the second member 20 is used as a heat radiating member (such as a heat sink) for an electronic component or the like, the laser joining intermediate member 1 can suppress the heat of the laser light L from being transmitted to the electronic component or the like. Is particularly useful.

  Next, examples and comparative examples of the present invention will be described.

Example 1
About the 1st member The 1st member 10 was taken as the board | plate material of nylon 66 (Unitika Co., Ltd. Maranil A226). The thickness is 5 mm and the dimensions are 100 mm × 100 mm. The first member 10 is milky white but can sufficiently transmit the laser beam. The thermal conductivity of the first member 10 was 0.23 W · m ⁻¹ · K ⁻¹ .

About the 2nd member The 2nd member 20 was made into the board | plate material of an aluminum alloy (A5052). The thickness is 10 mm and the dimensions are 100 mm × 100 mm. The surface of the second member 20 was subjected to hard alumite treatment. The thermal conductivity of the second member 20 was 236 W · m ⁻¹ · K ⁻¹ .

Regarding the intermediate member for laser bonding The main component of the intermediate member 1 for laser bonding is nylon 6 (A1030BRL manufactured by Unitika Ltd.), and 0.5% by weight of carbon black (PRINTEK 35 manufactured by Evonik Degussa Japan Co., Ltd.), polyamide A compound was prepared by adding 30% by weight of 12 series elastomer (UBESTAXPA9035X1 manufactured by Ube Industries, Ltd.) and kneading and dispersing. The compound was sandwiched between Teflon (registered trademark) sheets, molded using a 400 μm spacer, heated and melted by a hot plate, and then cooled to obtain a 400 μm laser joining intermediate member 1. The intermediate member 1 for laser bonding was formed into a belt shape having a width of 10 mm and a length of 100 mm.

This laser joining intermediate member 1 had a laser light absorptance of 60% at a wavelength of 940 nm. Further, the thermal conductivity of the intermediate member 1 for laser bonding was 0.235 W · m ⁻¹ · K ⁻¹ .

Joining Step First, the laser joining intermediate member 1 is bonded to the second member 20 by vibration welding or the like.

  Then, the 1st member 10 is piled up on the 2nd member 20 side of the intermediate member 1 for laser joining, and it clamps with a clamp instrument. The applied pressure is 10N.

  And the laser beam L was irradiated from the 1st member 10 side using the semiconductor laser irradiation apparatus. The wavelength of the laser beam L is 940 nm, and the output is 60 W. The irradiation site is the intermediate portion in the longitudinal direction of the intermediate member 1 for laser bonding, the focal point of the laser beam L is set at the interface between the first member 10 and the intermediate member 1 for laser bonding, and the scanning direction is the intermediate member for laser bonding. 1 in the longitudinal direction. The scanning distance is 25 mm. The scanning speed is 20 mm / second.

Tensile test After the laser bonding intermediate member 1 was cooled to room temperature, a tensile test was performed. The tensile test apparatus uses an autograph AG-IS manufactured by Shimadzu Corporation, and sandwiches the end of the first member 10 (left end of FIG. 1) and the end of the second member 20 (right end of FIG. 1). The sample was fixed to a tensile test apparatus with a tension of 5 mm / min and pulled in the left-right direction in FIG. This tensile test was performed both before and after the heat cycle. The heat cycle is a treatment in which a cycle of leaving in an atmosphere of −20 ° C. for 24 hours, then leaving in a room temperature atmosphere for 3 hours, and then leaving in an atmosphere of 80 ° C. for 24 hours is repeated three times.

  The tensile strength before the heat cycle was 1100 N, and the tensile strength after the heat cycle was 1070 N. It was found that sufficient joint strength was obtained in both cases. When observed after the tensile test, the resin material constituting the laser joining intermediate member 1 and the resin material constituting the first member 10 were sufficiently mixed, and cohesive failure occurred.

(Example 2)
The first member 10 and the second member 20 are the same as those in the first embodiment.

  The intermediate member 1 for laser bonding is different from that of Example 1 only in the amount of carbon black added and the thickness. That is, the addition amount of carbon black is 0.6% by weight, and the thickness of the intermediate member 1 for laser bonding is 1000 μm. This laser joining intermediate member 1 had a laser light absorption rate of 85% at a wavelength of 940 nm.

  As a result of conducting a tensile test on Example 2, it was found that the tensile strength before the heat cycle was 1300 N and the tensile strength after the heat cycle was 1280 N, both of which had sufficient bonding strength. When observed after the tensile test, the resin material constituting the laser joining intermediate member 1 and the resin material constituting the first member 10 were sufficiently mixed, and cohesive failure occurred.

(Example 3)
The first member 10 and the second member 20 are the same as those in the first embodiment.

  The intermediate member 1 for laser bonding is different from that of Example 1 in that the amount of carbon black added and the thickness thereof are different from those of Example 1, and further no elastomer is added. The amount of carbon black added is 0.5% by weight, and the thickness of the intermediate member 1 for laser bonding is 500 μm. This laser joining intermediate member 1 had a laser light absorption rate of 65% at a wavelength of 940 nm.

  As a result of conducting a tensile test on Example 3, it was found that the tensile strength before the heat cycle was 1200 N, and that sufficient bonding strength was obtained. On the other hand, the tensile strength after the heat cycle was 500N. The reason why the bonding strength decreased after the heat cycle is that the intermediate member 1 for laser bonding is not flexible, and the separation between the members 10 and 20 is caused by the difference in thermal expansion coefficient between the first member 10 and the second member 20. This is because the force could not be absorbed by the deformation of the intermediate member 1 for laser bonding.

(Comparative example)
The first member 10 and the second member 20 are the same as those in the first embodiment.

  The intermediate member 1 for laser bonding is different from that of Example 1 only in the amount of carbon black added and the thickness. That is, the addition amount of carbon black is 1.0% by weight, and the thickness of the intermediate member 1 for laser bonding is 250 μm. This laser joining intermediate member 1 had a laser light absorption rate of 70% at a wavelength of 940 nm.

  As a result of conducting a tensile test for the comparative example, the tensile strength before the heat cycle was 150 N, and the tensile strength after the heat cycle was 145 N, both of which were significantly lower than those of Examples 1 and 2. When observed after the tensile test, the resin material constituting the laser joining intermediate member 1 and the resin material constituting the first member 10 were not mixed, and interface peeling of the first member 10 occurred. This is because the intermediate member 1 for laser bonding is thinner than 300 μm, so that the effect as a heat insulating material is not exhibited, and the heat generated by the laser light irradiation is quickly taken away by the second member 20 having high thermal conductivity. This is because the amount of melting of the laser joining intermediate member 1 was small.

  As described above, it can be seen that when the thickness of the intermediate member for laser bonding 1 is less than 300 μm, the bonding strength is extremely reduced.

  The present invention can be widely applied when, for example, a resin material and a metal material such as home appliances, housing products, office supplies, toys, and automobile parts are joined.

  As described above, the laser joining intermediate member and the joining method using laser light according to the present invention can be applied, for example, when joining a resin material and a metal material.

1 Laser joining intermediate member 10 First member 20 Second member L Laser light

Claims (5)

In a laser joining intermediate member disposed between two members when joining a first member having laser light permeability and a second member having a higher thermal conductivity than the first member using a laser beam ,
An intermediate member for laser bonding, characterized in that it is made of a resin material that melts when irradiated with the laser light and has a thickness of 300 μm or more. In the intermediate member for laser bonding according to claim 1,
An intermediate member for laser joining, comprising a laser light absorbent and having a laser light absorption rate set to 40% or more. In the intermediate member for laser bonding according to claim 1 or 2,
An intermediate member for laser bonding, comprising a thermoplastic elastomer. An intermediate member for laser bonding is disposed between a first member having laser light permeability and a second member having a higher thermal conductivity than the first member, and the first member and the second member are bonded. In the joining method using laser light to
Bonding the intermediate member for laser bonding set to a thickness of 300 μm or more to the second member;
Thereafter, the first member is disposed on the opposite side of the intermediate member for laser bonding to the second member, and laser light is irradiated from the first member side to melt the intermediate member for laser bonding,
Thereafter, the laser joining intermediate member is cooled to cool the intermediate member for laser joining. In the joining method using the laser beam according to claim 4,
The heat transfer coefficient of the first member is set to 0.1 or more and 1.0 W · m ⁻¹ · K ⁻¹ or less,
A joining method using laser light, wherein the heat transfer coefficient of the second member is set to 100 W · m ⁻¹ · K ⁻¹ or more.

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