JP2011240497A - Joining method using laser beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To join members made of materials which can not easily be welded to each other together to have sufficient joining strength by a joining method using a laser beam.SOLUTION: An intermediate material 5 made of a polymer alloy is arranged between a first member 2 and a second member 3. The polymer alloy contains a first resin having fusibility with a resin constituting the first member 2 and a second resin having fusibility with a resin constituting the second member 3. The difference between the solubility parameter of the resin constituting the first member 2 and the solubility parameter of the first resin is set to be 1.0 or below, and the difference between the solubility parameter of the resin constituting the second member 3 and the solubility parameter of the second resin is set to be 1.0 or below. The difference in solubility parameter of the first and second resins of the polymer alloy is made smaller than the difference in solubility parameter of the resin constituting the first member 2 and the resin constituting the second member 3. The intermediate material 5 is heated by being irradiated with the laser beam, the first resin in the polymer alloy and the first member 2 are fused together, and the second resin in the polymer alloy and the second member 3 are fused together.

Description

  The present invention relates to a joining method for joining a first member and a second member using a laser beam.

  Conventionally, for example, as a method of joining a first member and a second member made of a resin material, a joining method of irradiating laser light has been widely used (see, for example, Patent Documents 1 to 3). In Patent Documents 1 to 3, a laser light absorber made of a toner or a paint that absorbs laser light is interposed between the first member and the second member, and the laser light is absorbed by the laser light absorber. The joining portion of the member and the second member is heated and melted, thereby joining the first and second members.

JP 2003-181931 A JP 2004-1071 A JP 2005-238462 A

  By the way, the above-described joining method using laser light has high productivity, and it is desired to expand its application range. However, although the joining methods of Patent Documents 1 to 3 can be applied in the case where the first member and the second member are easily fused, the types of materials of the first member and the second member are different. In the case of a material that is difficult to be fused, such as when compatibility is poor, even if the methods of Patent Documents 1 to 3 are used, sufficient bonding strength cannot be ensured, and as a result, laser light is used. The application range of the joining method is narrow.

  Therefore, when the first member and the second member made of materials that are difficult to fuse with each other are fused, a polymer alloy is prepared by mixing the material of the first member and the material of the second member. It is conceivable to provide between the first member and the second member and to melt them by heating with laser light. According to this, it becomes possible to fuse the polymer alloy to the first member and to the second member.

  However, since the material of the first member and the material of the second member are originally based on the premise that they are not compatible and difficult to fuse, the bond between the two resins in the polymer alloy is weak. Therefore, it is considered that satisfactory bonding strength cannot be obtained even by this method.

  The present invention has been made in view of such points, and the object of the present invention is to provide sufficient bonding strength between members made of materials having poor compatibility with each other and difficult to fuse by a bonding method using laser light. It is to be able to join with having.

  In order to achieve the above object, in the present invention, laser beams are used for members made of materials that are difficult to fuse together by devising a polymer alloy disposed between the first member and the second member. It was made possible to join by the joining method.

  A first invention is a first member formed by molding a resin, and a second member formed by molding a resin having a solubility parameter of 2.0 or more apart from a solubility parameter of the resin constituting the first member. Are bonded to each other by irradiating a laser beam with an intermediate material made of a polymer alloy between the two members, and the polymer alloy has a fusion property with the resin constituting the first member. And a second resin having a fusing property with the resin constituting the second member, and constituting the first member with the solubility parameter of the first resin in the polymer alloy. The difference between the solubility parameter of the resin is set to 1.0 or less, and the difference between the solubility parameter of the second resin in the polymer alloy and the solubility parameter of the resin constituting the second member is set to 1.0. Set below and above The difference in solubility parameter between the first resin and the second resin in the remer alloy is set smaller than the difference in solubility parameter between the resin constituting the first member and the resin constituting the second member, An intermediate member is disposed between the first member and the second member, and then the intermediate member is irradiated with laser light in a state where the first member, the intermediate member, and the second member are stacked. And the first resin in the polymer alloy and the first member are fused, and the second resin in the polymer alloy and the second member are fused.

  According to this configuration, the difference in solubility parameter between the first resin in the polymer alloy of the intermediate material and the resin constituting the first member is 1.0 or less, and the solubility parameters of both are close. One resin and the first member are likely to be fused. Similarly, the second resin and the second member in the polymer alloy of the intermediate material are easily fused. Further, the difference in solubility parameter between the first resin and the second resin in the polymer alloy is smaller than the difference in solubility parameter between the resin constituting the first member and the resin constituting the second member. The bond between the first resin and the second resin is also strong. As a result, even if the solubility parameter of the resin constituting the first member and the second member is 2.0 or more and difficult to fuse, sufficient bonding strength between the first member and the second member can be obtained. It is done.

  According to a second invention, in the first invention, at least one of the first resin and the second resin of the polymer alloy as an intermediate material is an elastomer.

  That is, when the first member and the second member are fused by laser light irradiation, they are subjected to a thermal cycle in which they are heated and then cooled. At this time, stress may be generated at the joint interface due to a difference in linear expansion coefficient between the first member and the second member.

  On the other hand, in the second invention, since the polymer alloy has elasticity, the stress at the bonding interface is relieved by the elastic deformation of the polymer alloy.

  In addition, after joining the first member and the second member, thermal stress or mechanical force may be applied during use to generate stress at the joining interface between the first member and the second member. Such stress is also relieved by elastic deformation of the polymer alloy.

  According to the first invention, an intermediate material made of a polymer alloy is disposed between the first member made of resin having a solubility parameter of 2.0 or more and the second member, and the first member in the polymer alloy The difference in solubility parameter between the resin and the resin constituting the first member, and the difference in solubility parameter between the second resin in the polymer alloy and the resin constituting the second member are both 1.0 or less, and The difference in solubility parameter between the first resin and the second resin in the polymer alloy is made smaller than the difference in solubility parameter between the resin constituting the first member and the resin constituting the second member. As a result, the first member and the second member can be bonded with sufficient bonding strength via the intermediate material, so that the application range of the bonding method using laser light can be expanded.

  According to the second invention, since at least one of the first resin and the second resin of the polymer alloy is an elastomer, the bonding interface between the first member and the second member at the time of or after the bonding with the laser beam. The stress of can be relieved. As a result, it is possible to prevent a reduction in bonding strength and peeling, and to maintain a high bonding strength even when used for a long period of time.

It is sectional drawing of the joining goods obtained by the joining method using the laser beam concerning embodiment. It is sectional drawing which shows the state before joining each member.

  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 shows a bonded product 1 obtained by a bonding method using laser light according to an embodiment of the present invention. The joined product 1 is obtained by integrating a first member 2 and a second member 3 with an intermediate material 5 interposed therebetween. Although the details will be described later, the first member 2 and the second member 3 are made of different types of resins.

  The first member 2 is a plate-like member, and may be made of a material that does not allow laser light to pass therethrough or may be made of a material that has laser light permeability that allows laser light to pass through. Good. Here, the laser beam impermeability is a laser beam absorptivity that absorbs the laser beam, and refers to the property of absorbing the remainder even if the laser beam as a heating source is partially transmitted and / or reflected, Includes those that absorb all of the laser light. As a material having such properties, for example, there is a material obtained by mixing a pigment or a dye with a resin.

  In the present embodiment, the first member 2 is made of, for example, polypropylene. The SP value (solubility parameter) of polypropylene is calculated by a method using a calculation formula shown below, that is, a so-called Fedors method.

In the above formula, δ is an SP value, V is a molar volume, and Ecoh is a binding energy. The unit of SP value is (MPa) ^1/2 .

When the SP value of polypropylene is calculated from the structural formula using the above formula, it is 16.3 (MPa) ^1/2 . What is necessary is just to determine the structural formula of the compound to obtain | require using normal structural-analysis methods, such as IR, NMR, a mass spectrum. Polypropylene is widely used as a recycled material particularly in the automobile industry, and is used for automobile interior members, lamp housing parts, and the like. In addition, polypropylene is used in a wide range from housing equipment or exterior members for electrical products, stationery, and furniture, and its uses are wide.

  The second member 3 is a plate-like member made of a material that is colorless and transparent and has a laser beam permeability that allows laser light to pass therethrough. Laser light transmission means that the laser beam as a heating source is transmitted with almost no reflection or absorption, or the remaining laser beam is transmitted without melting even if the laser beam is partially transmitted and / or reflected. This includes the properties that can be transmitted, including those that transmit all of the laser light.

The second member 3 is made of, for example, polymethyl methacrylate resin (hereinafter referred to as PMMA). The SP value of PMMA is 19.8 (MPa) ^1/2 by the above calculation method. PMMA is used, for example, as a window of a machine tool, a display part of an electric product, a lens cover adjacent to the above-described housing of an automobile lamp, and the like. In addition, PMMA has been used in a wide range from housing equipment or exterior members for electrical products, stationery, and furniture, and its application is wide.

  Since the SP value of the resin (polypropylene) constituting the first member 2 is 16.3 and the SP value of the resin (PMMA) constituting the second member 3 is 19.8, the difference between the SP values ( (Absolute value) is 3.5. That is, the SP value of the resin constituting the first member 2 and the SP value of the resin constituting the second member 3 are separated by 2.0 or more. If the SP value is 2.0 or more, the compatibility is poor, so that the bonding strength is such that the first member 2 and the second member 3 are melted and then solidified by laser light irradiation and can be practically used. Cannot be obtained. That is, the meltability between the first member 2 and the second member 3 is poor.

  For the resin constituting the first member 2 and the second member 3, for example, a thermal stabilizer, an antioxidant, an ultraviolet stabilizer, a conductive agent, a nucleating agent, a release agent, a flame retardant, and an antistatic agent. It is also possible to mix at least one selected from the group consisting of processing preparations, colored and functional pigments or dyes, crosslinking agents, plasticizers and vulcanizing agents. When a color pigment or dye is mixed in the second member 3, the second member 3 is not colorless and transparent, but may be of an amount that can ensure a predetermined laser beam transparency.

  Although the thickness of the 1st member 2 and the 2nd member 3 is not specifically limited, For example, it is about 0.5 mm-several mm.

  The intermediate material 5 is made of a polymer alloy including a first resin having a fusing property with the resin constituting the first member 2 and a second resin having a fusing property with the resin constituting the second member 3. Is. The intermediate material 5 is basically in the form of a sheet, but the shape is not limited to this, and any shape that can effectively join the first member 2 and the second member 3 may be used. The thickness of the intermediate material 5 is preferably 10 μm or more and 2000 μm or less, but is not limited to this range. If the intermediate material 5 is extremely thin, it will exhibit a film shape, while if it is thick, it will exhibit a plate shape. The polymer alloy has elasticity, and the elastic modulus is set to 0.01 or more and 500 MPa or less. The value of the elastic modulus can be arbitrarily set depending on the type of the first resin and the second resin, the type and amount of the elastomer mixed in the polymer alloy, and the like.

  The first resin in the polymer alloy is a resin having good compatibility with the resin constituting the first member 2. For example, the difference in SP value between the first resin and the resin constituting the first member 2 is 1. It is as follows. Therefore, the fusing property between the first resin and the first member 2 in the polymer alloy is good.

  That is, when the resin constituting the first member 2 is polypropylene, the first resin has an SP value of 15.3 or more and 17.3 or less, that is, if the difference in SP value is 1.0 or less. Well, for example, natural rubber, butadiene rubber, styrene-ethylene-butylene-styrene rubber (SEBS), styrene-butadiene-styrene rubber (SBS), styrene-isoprene-styrene rubber (SIS), etc. Examples thereof include, but are not limited to, and other resins can also be used.

  The second resin in the polymer alloy is a resin having good compatibility with the resin constituting the second member 3. For example, the difference in SP value between the second resin and the resin constituting the second member 3 is 1. It is as follows. Therefore, the fusion property between the second resin in the polymer alloy and the second member 3 is good.

  That is, when the resin constituting the second member 3 is PMMA, the SP value of the second resin is 18.8 or more and 20.8 or less, and the difference in SP value from the first resin is What is necessary is just to be smaller than the difference in solubility parameter between the resin constituting the first member 2 and the resin constituting the second member 3, for example, chloroprene rubber, methyl methacrylate-butyl acrylate-butyl methacrylate copolymer ( Examples thereof include a copolymer based on MAM) and an acrylic resin, a resin copolymerized with acrylonitrile, an elastomer, and the like. However, the present invention is not limited to these, and other resins can also be used.

  As described above, the difference in SP value between the first resin and the second resin in the polymer alloy is smaller than the difference in solubility parameter between the resin constituting the first member 2 and the resin constituting the second member 3. Therefore, the compatibility between the first resin and the second resin in the polymer alloy is better than the compatibility between the resin of the first member 2 and the resin of the second member 3.

  The intermediate material 5 is mixed with a laser light absorbent that absorbs laser light. Examples of the laser light absorber include carbon black, but are not limited thereto.

  The intermediate material 5 only needs to contain at least the first resin and the second resin described above. For example, the intermediate material 5 has practical properties such as improved heat resistance, improved waterstop, and good workability. For the purpose of improving the quality, various resins may be added. The amount of these resins added is preferably 10 parts by weight or less when the intermediate material 5 is 100 parts by weight, but may be 50 parts by weight or less, for example.

  If the resin added to the intermediate material 5 is, for example, a thermoplastic resin, specifically, 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 ), Ethylene tetrafluoroethylene copolymer, liquid crystal polymer, polybutylene terephthalate, polyether ether ketone, polyether ketone, polyether ketone ketone, polyethylene naphthalene, Examples include polyethylene terephthalate, polyimide, polyacetal, polyamideimide, polyphenylene ether, polyphenylene oxide, polycarbonate, polyphenylene sulfide, polysulfone, polythioethylsulfone, polytetrafluoroethylene, polyethersulfone, and polyetherimide.

  In addition, a modified resin in which a polar functional group is chemically bonded may be added to the intermediate material 5. Specifically, an acrylic acid-modified olefin resin, a maleic acid-modified olefin resin, a chlorinated modified olefin resin (CPP, CPE). , Silane-modified olefin resin, ionomer resin, nylon-modified olefin resin, epoxy-modified resin, ethylene vinyl alcohol resin (EVOH), ethylene vinyl acetate resin, hot melt adhesive resin, etc., and mixtures of these with the above thermoplastic resins Or a copolymer composition may be sufficient.

  In addition, a thermoplastic elastomer as a resin may be added to the intermediate material 5, and specifically, a styrene elastomer, an olefin elastomer, a polyester elastomer, a vinyl chloride elastomer, a polyamide elastomer, a polybutadiene elastomer, an isoprene-based resin. Examples include elastomers, ion clusters and amorphous PE elastomers, chlorinated PE and amorphous PE elastomers, fluorine elastomers, polyurethane elastomers, and acrylic elastomers.

  A thermosetting resin can also be added to the intermediate material 5 to such an extent that the thermoplasticity is not impaired. Specifically, a phenol resin, a urea resin, a melamine resin, an epoxy resin, an unsaturated polyester resin, etc. are mentioned. Similarly, rubber may be added as a thermosetting resin. Specifically, natural rubber, isoprene rubber, ethylene propylene diene rubber, ethylene propylene rubber, styrene butadiene rubber, butadiene rubber, chlorosulfonated polyethylene rubber, Examples include isoprene rubber, chloroprene rubber, acrylic rubber, epichlorohydrin rubber, urethane rubber, nitrile rubber, hydrogenated nitrile rubber, fluorine rubber, and silicon rubber.

  A copolymer of the above elastomer may be added to the intermediate material 5.

  Further, an adhesive component may be added to the intermediate material 5. Examples of the adhesive component include rubber, acrylic, urethane, and silicon. Thermoplastic elastomers are also commonly used as a base for rubber-based pressure-sensitive adhesives, and are not particularly limited, but can be made into pressure-sensitive adhesives by blending tackifier, oil, liquid oligomers, crosslinking agents and the like.

  A tackifier may be added to the intermediate material 5. Specific examples of the tackifier include a rosin tackifier resin, a terpene tackifier resin, a hydrocarbon tackifier resin, a coumarone resin, and a coumarone. Examples include indene resins. The oil may be selected from roughly classified paraffinic, naphthenic, and aromatic types. The liquid oligomer can be selected from acrylics, styrenes, rubbers such as polyisoprene and butadiene, polyesters, and other high-viscosity polymers having a molecular weight of about several hundred to several thousand.

  Moreover, a reinforcing material and a filler can be added to the resin described above at 40 parts by weight or less. Reinforcing materials and fillers include, for example, potassium titanate, aluminum borate, magnesium sulfate, calcium carbonate and their whiskers, glass fibers, carbon fibers, metal fibers, aramid fibers, asbestos, silicon carbide, ceramics, barium sulfate, Calcium sulfate, kaolin, clay, silica, pyrophyllite, bentonite, sericite, zeolite, montmorillonite, mica, mica, nepheline cinteite, talc, talbalsite, wollastonite, PMF, ferrite, calcium silicate, calcium carbonate , Magnesium carbonate, dolomite, silica, zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass beads, glass powder, glass balloon, quartz, quartz glass and the like.

  Moreover, it is also possible to mix a filler with the intermediate material 5, and in this case, the filler may be hollow. Further, two or more kinds of fillers can be mixed, and can be used after pretreatment with a coupling agent such as silane or titanium as required.

  Organic and inorganic color pigments and dyes can be added to the intermediate material 5, and the amounts of these, the reinforcing material, and the filler are such that the intermediate material 5 can ensure predetermined laser light absorption. Thus, it can be adjusted as appropriate.

  In addition to the intermediate material 5, various additives may be blended as necessary. For example, peptizers, scorch inhibitors, plasticizers, flame retardants, antioxidants, heat stabilizers, light stabilizers, UV absorbers, lubricants, pigments, crosslinking agents, crosslinking aids, vulcanizing agents, vulcanization Common rubber plastic compounding chemicals such as an accelerator, a vulcanization return preventing agent, a silane coupling agent, and a titanate coupling agent can be mentioned.

  Some of the above-described components that can be included in the intermediate material 5 are thermosetting, but the intermediate material 5 only needs to have thermoplasticity when irradiated with laser light L described later. , It may contain a thermosetting resin, a curing reaction may occur during material processing, a curing reaction may occur due to heat generated during irradiation with the laser beam L, and irradiation with the laser beam L A curing reaction may occur later.

  As the laser beam impermeability of the intermediate material 5, for example, it is preferable that the absorptance of the laser beam having a wavelength of 940 nm is 15% or more.

  Next, the manufacturing procedure of the joined product 1 will be described.

  The intermediate member 5 is disposed between the first member 2 and the second member 3, and the first member 2, the intermediate member 5, and the second member 3 are overlapped. At this time, the first member 2 and the second member 3 may be clamped in the thickness direction using a jig (not shown).

  Then, as shown in FIG. 1, the laser beam L is irradiated toward the intermediate member 5 from the second member 3 side. The type of the laser beam L can be appropriately selected according to the material, thickness, shape, laser beam transmission degree, and the like of the objects to be joined (first member 2, intermediate member 5 and second member 3). As a device for irradiating the laser beam L, a known device can be used.

  As the type of the laser beam L, for example, a gas laser, for example, a solid laser (Nd: YAG excitation, semiconductor laser excitation, etc.), a semiconductor laser, a tunable diode laser, a titanium sapphire laser (Nd: YAG excitation), etc. are used. The type of the laser beam L is not limited. Of these laser beams, a laser beam having an oscillation wavelength of 800 to 1600 nm, preferably 800 to 1100 nm, which is longer than visible light is usually used. Further, the laser beam L may be composed of one wavelength, or may have two or more wavelengths. As the beam shape of the laser light L, a circle, an ellipse, a line, a donut shape, or the like can be selected as necessary.

  The laser beam L may be irradiated from a vertical direction or an oblique direction with respect to the intermediate portion in the thickness direction of the bonding target. The laser beam L may be emitted from a plurality of directions as well as one direction. The laser beam L may be irradiated while moving the object to be joined, or spot irradiation, pulse irradiation, line irradiation, and collective irradiation for the shape to be fused may be performed simultaneously by a single laser beam or a plurality of laser beams.

  Also, if the output of the laser beam L is too low, it becomes difficult to melt the joint parts of the resin, and if the output is too high, the resin evaporates or deteriorates and the strength decreases. The output of the laser beam L as conditions, the scanning speed, the focal position, the clamping pressure by the clamping jig to the object to be joined, etc. are adjusted as appropriate.

  The irradiated laser beam L passes through the second member 3 and reaches the intermediate material 5. The laser beam L that has reached the intermediate material 5 is absorbed by the laser absorbent of the intermediate material 5, thereby heating the intermediate material 5.

  When the intermediate material 5 is heated to the melting temperature, it starts to melt. The heat of the intermediate member 5 is transmitted to the first member 2 and the second member 3, and the resin at the joint portion between the first member 2 and the second member 3 is also melted.

  When the joining portion of the intermediate member 5 and the first member 2 is melted, the polymer alloy of the intermediate member 5 is mixed with the resin of the joining portion of the first member 2. Further, when the resin at the joint portion between the intermediate member 5 and the second member 3 is melted, the polymer alloy of the intermediate member 5 is mixed with the resin at the joint portion of the second member 3.

  Further, since the intermediate material 5 is provided with a laser absorptivity, the intermediate material 5 can be reliably heated and melted even when a low-power laser beam is used. Therefore, the first member 2 and the second member 3 can be prevented from being damaged (burned or deformed) by heat.

  After the irradiation with the laser beam L is completed, the intermediate material 5 is cooled and solidified. When the intermediate material 5 is solidified, the first resin in the polymer alloy of the intermediate material 5 is fused with the resin constituting the first member 2, and the second resin in the polymer alloy is fused with the second member 3. It will be in a worn state. Thereby, the 1st member 2 and the 2nd member 3 are joined, and the joined article 1 is obtained.

  Since the difference in SP value between the first resin in the polymer alloy of the intermediate material 5 and the resin constituting the first member 2 is 1.0 or less and the compatibility between them is good, the intermediate material 5 and the first member The bonding strength with 2 is high. In addition, since the difference in SP value between the second resin in the polymer alloy of the intermediate material 5 and the resin constituting the second member 3 is 1.0 or less and the compatibility between the two is good, the intermediate material 5 and the second resin The bonding strength with the member 3 is high. Furthermore, since the difference in SP value between the first resin and the second resin in the polymer alloy is smaller than the difference in solubility parameter between the resin constituting the first member 2 and the resin constituting the second member 3, The bond between the first resin and the second resin is also strong.

  The joined product 1 integrated in this manner exhibits practically sufficient strength at the fusion site. Further, when the bonded product 1 is subjected to a tensile shear bond strength test according to JIS K6850-1999 at a tensile speed of 5 mm / min, the tensile shear bond strength is 500 N or more.

  Further, when the first member 2 and the second member 3 are fused by irradiation with the laser beam L, they are subjected to a thermal cycle in which they are heated and then cooled. At this time, stress may be generated at the bonding interface due to a difference in linear expansion coefficient between the first member 2 and the second member 3. In contrast, since the intermediate member 5 has elasticity, the stress at the joint interface can be relaxed. As a result, it is possible to prevent a reduction in bonding strength and peeling.

  In addition, in the obtained bonded product 1, thermal stress or mechanical force is applied during use, and stress may be generated at the bonding interface between the first member 2 and the second member 3. Can be relieved by the presence of the intermediate material 5. Accordingly, the bonding strength can be maintained even when the bonded product 1 is used for a long period of time.

  As described above, according to the joining method using the laser according to this embodiment, the intermediate material 5 made of a polymer alloy is disposed between the first member 2 and the second member 3, and The difference in solubility parameter between the first resin and the resin constituting the first member 2 and the difference in solubility parameter between the second resin in the polymer alloy and the resin constituting the second member 3 are both 1.0. In addition, the difference in solubility parameter between the first resin 2 and the second resin 3 in the polymer alloy is defined as the solubility parameter between the resin constituting the first member 2 and the resin constituting the second member 3. It is smaller than the difference. Thereby, even if the solubility parameter of the resin constituting the first member 2 and the second member 3 is 2.0 or more and difficult to be fused, the first member and the second member are sufficiently bonded. Can be joined with strength. Therefore, the application range of the bonding method using laser light can be expanded.

  In addition, since the polymer alloy is made elastic, the stress at the bonding interface between the first member 2 and the second member 3 can be relieved at the time of bonding with the laser beam or after bonding. As a result, it is possible to prevent a reduction in bonding strength and peeling, and to maintain a high bonding strength even when used for a long period of time.

  In the above-described embodiment, the laser beam is irradiated from the second member 3 side. However, the present invention is not limited to this, and the first member 2 is constituted by a member having laser beam transparency, and the first member 2 side. You may make it irradiate a laser beam from. Thereby, the laser beam irradiated from the 1st member 2 side reaches the intermediate material 5, and the intermediate material 5 is heated.

  Moreover, the joining method using the laser beam concerning this invention is applicable when manufacturing various joining goods besides the components for motor vehicles, the case for cosmetics, the housing use, or the exterior member for electrical products, for example.

  Embodiments of the present invention will be described below with reference to Table 1.

  The first member 2 is the same member in all of Comparative Examples 1 to 3 and Examples, and is a plate made of polypropylene. Specifically, as the polypropylene, Sun Allomer PM771M manufactured by Sun Allomer Co., Ltd. is used. The plate thickness of the first member 2 was 2 mm and the width was 25 mm. The laser transmittance is 7%, and the SP value is 16.3 as described above.

  The second member 3 is the same member in all of Comparative Examples 1 to 3 and Examples, and is a plate material made of PMMA. Specifically, Acrylite L-001 manufactured by Mitsubishi Rayon Co., Ltd. is used. The plate thickness of the second member 3 was 2 mm, and the width was 25 mm. The laser transmittance is 93%, and the SP value is 19.8 as described above.

  The laser beam L was output from the semiconductor laser device, the wavelength was 940 nm, the output was 250 W, and the scanning speed was 1.2 m / min. It is the same in all of Comparative Examples 1 to 3 and Examples.

  First, Comparative Example 1 will be described. In Comparative Example 1, the first member 2 and the second member 3 are directly stacked in a range of width 25 mm × depth 35 mm without using the intermediate material 5, and the laser beam L is irradiated from the second member 3 side, and the width direction Scanned. As a result, it was impossible to fuse the first member 2 and the second member 3 together. That is, the first member 2 is peeled off from the third member 3 with little force applied. The reason is that the SP value of the resin of the first member 2 and the resin of the second member 3 is 2.0 or more apart and the compatibility is poor.

  Next, Comparative Example 2 will be described. In the comparative example 2, the 1st member 2, the intermediate material (different from the thing of this invention), and the 2nd member 3 were piled up in order, and the laser beam L was irradiated. The overlapping range and the irradiation direction of the laser light L are the same as in Comparative Example 1. The intermediate material is made of MAM, the size is 25 mm wide × 35 mm deep, and the thickness is 0.5 mm. The product name of MAM is LA4285. The SP value of MAM is 19.7. As a result, the fusion was impossible as in Comparative Example 1.

  Next, Comparative Example 3 will be described. In the comparative example 3, the 1st member 2, the intermediate material (different from the thing of this invention), and the 2nd member 3 were piled up in order, and the laser beam L was irradiated. The overlapping range and the irradiation direction of the laser light L are the same as in Comparative Example 1. The intermediate material is made of SIS, and the size and thickness are the same as those of the intermediate material of Comparative Example 2. The product name of SIS is QUINTAC 3421. The SP value of SIS is 17.3. As a result, destruction occurs at the bonding interface, and only a weak bonding force that allows the first member 2 to be easily peeled from the second member 3 by hand is obtained. Specifically, the test method of the bonding strength is that the first member 2 and the second member 3 in the bonded state are subjected to a tensile force in the shearing direction and in a direction orthogonal to the scanning direction of the laser beam L (a tensile speed of 5 mm / Min). In this test method, peeling was performed with a tensile force of 50N.

  Next, examples of the present invention will be described. In the Example, the 1st member 2, the intermediate material 5, and the 2nd member 3 were piled up in order, and the laser beam L was irradiated. The overlapping range and the irradiation direction of the laser light L are the same as in Comparative Example 1. As the intermediate material 5, the same SIS as the intermediate material of Comparative Example 3 was used as the first resin, and the same MAM as the intermediate material of Comparative Example 2 was used as the second resin, and these were mixed. Moreover, 0.5 weight part of near-infrared absorption pigment | dye (IR-13F by Showa Denko KK) was added to the intermediate material 5 as a laser beam absorber. The size and thickness of the intermediate material 5 are the same as those in Comparative Example 1. The result was difficult to peel off by hand. Specifically, peeling was performed with a tensile force of 1000 N by the above test method, and at this time, the intermediate material 5 had caused cohesive failure. Thus, according to the present invention, it has been found that sufficient bonding strength can be obtained.

  As described above, the joining method using laser light according to the present invention can be used, for example, when manufacturing automotive parts, cosmetic cases, housing or electrical product exterior members, and the like.

1 Joined product 2 First member 3 Second member 5 Intermediate material L Laser beam

Claims (2)

A first member formed by molding a resin, and a second member formed by molding a resin having a solubility parameter apart from 2.0 or more by the solubility parameter of the resin constituting the first member, In the joining method of joining by irradiating laser light with an intermediate material made of polymer alloy in between,
The polymer alloy includes a first resin having a fusing property with a resin constituting the first member and a second resin having a fusing property with a resin constituting the second member, The difference between the solubility parameter of the first resin in the polymer alloy and the solubility parameter of the resin constituting the first member is set to 1.0 or less, and the solubility parameter of the second resin in the polymer alloy; The difference between the solubility parameter of the resin constituting the second member is set to 1.0 or less, and the difference in solubility parameter between the first resin and the second resin in the polymer alloy is defined as the first parameter. Set smaller than the difference in solubility parameter between the resin constituting the member and the resin constituting the second member,
The intermediate member is disposed between the first member and the second member;
Next, in a state where the first member, the intermediate material, and the second member are stacked, the intermediate material is heated by irradiating a laser beam to melt the first resin and the first member in the polymer alloy. And joining the second resin in the polymer alloy and the second member together with a laser beam. In the joining method using the laser beam according to claim 1,
A joining method using laser light, wherein at least one of a first resin and a second resin of an intermediate polymer alloy is an elastomer.

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