JP2019058949A - Manufacturing method of composite member - Google Patents

Abstract

To provide a manufacturing method of a composite member in which an aluminum die casting member and a polymer member are rigidly adhered to each other by removing a carbide film on the surface of the aluminum die casting member and homogenizing a surface layer.SOLUTION: A manufacturing method of a composite member made by compounding an aluminum die casting member and a polymer member includes a melting process of melting a surface layer of a joint surface by irradiating the joint surface with the polymer member on the aluminum die casting member with laser beams and a compounding process of integrally forming polymer material onto the joint surface. The manufacturing method of the composite member preferably has a removal process for removing a carbide film existing on the joint surface by irradiating the joint surface with laser beams before the melting process, and preferably has a reforming process of applying hydroxide groups onto the joint surface by irradiating the joint surface with plasma beams after the melting process.SELECTED DRAWING: None

Description

  The present invention relates to a method of manufacturing a composite member in which an aluminum die-cast member and a polymer member are combined.

  As a case of an electronic control device such as an engine control unit mounted on a car, a composite member in which a polymer member made of silicone rubber or the like is adhered to a housing which is an aluminum die-cast member is used. As an aluminum alloy for die casting (die casting), ADC12 of an Al-Si-Cu-based alloy and the like are known. However, there is a problem that the aluminum die-cast member and the polymer member obtained by die-casting an aluminum alloy such as the ADC 12 have poor adhesion.

  There are various factors such as the contamination of organic matter, and the factors that inhibit the adhesion are, among others, the existence of a carbide film formed on the surface of the aluminum die-cast member. The carbide film is considered to be composed of a residue of a release agent (a mixture of oil, silicon, wax and the like) applied to a mold when manufacturing an aluminum die-cast member. The release agent is graphitized by heating at the time of die casting, and remains as a hard carbide film on the surface of the aluminum die-cast member. Even when a carbide film was adhered to the surface of the aluminum die-cast member, the polymer member was peeled off at the interface, so that both could not be adhered sufficiently.

JP, 2014-86682, A JP, 2009-155358, A JP, 2016-129942, A

  It is difficult to remove the carbide film formed on the surface of the aluminum die-cast member by cleaning with an organic solvent or ultrasonic cleaning. For this reason, it is necessary to perform wet processing such as acid or alkali cleaning and blast processing such as bead blasting. However, in the case of the wet processing, it is difficult to control the process, for example, it is necessary to adjust the concentration of the chemical solution and to suppress the reattachment of the stain. In the case of the blasting process, asperities are formed on the surface of the aluminum die-cast member due to the collision of the projection material, and there is a possibility that the adhesiveness is impaired.

  For example, as a method of improving adhesion without removing a carbide film, Patent Document 1 forms a silicon-based thin film or a carbon-based thin film on the surface of an aluminum die-cast member by plasma CVD method, and A method of bonding an aluminum die cast member and a seal member made of a silicone adhesive is described. Patent Document 2 describes a method of bonding a cured product of a moisture-curable silicone rubber composition (silicone rubber) and a substrate through a silicon oxide film formed by combustion of an organosilicon compound. In the method described in Patent Document 2, a process of spraying a flame of a fuel gas containing an organosilicon compound onto the surface of a substrate is performed. For this reason, the damage to a base material is large. In addition, although the aluminum die-cast member is not described as a base material in patent document 2, metal housings, such as an aluminum die-cast, as a member made to adhere to silicone rubber on the opposite side to a base material in paragraph [0033]. Is described. The subsequent paragraph [0034] describes that an oxide film or the like may be formed in advance on the surface of the metal casing in order to enhance the adhesion. As described above, Patent Documents 1 and 2 only describe a method of newly forming a thin film instead of removing the carbide film.

  It is difficult to equalize the adhesion degree and composition of the carbide film every time it is manufactured. For example, in one aluminum die-cast member, there may be a portion in which a large amount of carbide film is attached, a portion in which no carbide film is attached, or the like. In such a case, when a thin film is newly formed on the carbide film, the adhesiveness in the vicinity of the boundary between the portion to which the carbide film is attached and the portion to which the carbide film is not attached tends to be unstable. Furthermore, when the carbide film itself is fragile, the adhesion strength caused by it is lowered, which causes the deterioration of productivity.

  Moreover, as a factor which inhibits the adhesiveness in an aluminum die-cast member, not only the existence of a carbide film but the existence of a grain boundary is mentioned. In the surface layer of the aluminum die-cast member, crystal grain boundaries are formed by uneven distribution of trace metal components such as copper and iron other than aluminum in the form of islands. The inventors of the present invention have found that, in the grain boundary, the way in which hydroxyl groups are attached differs from that in other parts, or electrons move between foreign metals and corrosion tends to progress, so the grain boundary It has been found that if present, adhesion is likely to decrease.

  In this respect, Patent Document 3 describes a method of forming a perforated portion having an opening in the surface of a metal member, modifying the surface by plasma treatment, laser treatment or the like, and then bonding the resin member. In the method described in Patent Document 3, the resin member is filled in the perforated portion formed in the metal member, and the bonding effect of the both is improved by the anchor effect. Further, surface modification by plasma treatment, laser treatment or the like is a treatment for forming an oxide film on the surface of a metal member. As described above, in Patent Document 3, nothing is described about the influence of the carbide film and the grain boundaries in the aluminum die-cast member on the adhesion, and naturally, no countermeasure is considered.

  The present invention has been made in view of such an actual situation, and by removing the carbide film on the surface of the aluminum die-cast member and homogenizing the surface layer, the aluminum die-cast member and the polymer member are firmly bonded. An object of the present invention is to provide a method of manufacturing a composite member.

  In order to solve the above problems, the method for producing a composite member of the present invention is a method for producing a composite member in which an aluminum die-cast member and a polymer member are composited, and the method for producing the composite member with the polymer member in the aluminum die-cast member The method is characterized by including a melting step of irradiating the bonding surface with a laser to melt the surface layer of the bonding surface, and a compounding step of integrally molding a polymer material on the bonding surface.

  In the method of manufacturing a composite member of the present invention, the surface layer of the bonding surface is melted by irradiating the bonding surface of the aluminum die-cast member with the polymer member with a laser. By so doing, aggregates of trace metal components such as copper and iron that were unevenly distributed in the surface layer are melted and dispersed, the grain boundaries are reduced, and the surface layer is homogenized. Therefore, it is possible to suppress adhesion failure due to uneven distribution of hydroxyl groups and adhesion failure due to corrosion, which have conventionally occurred at grain boundaries. In addition, when the surface layer is melted, the carbide film formed on the bonding surface is also removed. As a result, the oxide layer (natural oxide layer) originally generated naturally under the carbide film is exposed, and the melting proceeds in that state, whereby the chemical bond on the surface of the oxide layer is broken, and the bonding surface Is activated. As a result, many hydroxyl groups are generated on the bonding surface after the melting step. By the reaction between the hydroxyl group and the material (polymer material) for forming the polymer member to cause a chemical bond, strong bonding between the aluminum die-cast member and the polymer member can be realized. As described above, according to the manufacturing method of the present invention, a composite member having high durability can be manufactured which is unlikely to cause interfacial peeling of the polymer member.

It is a top view of the test piece manufactured in the example.

  The method for producing a composite member of the present invention is a method for producing a composite member in which an aluminum die-cast member and a polymer member are combined, and has a melting step and a combining step.

  The aluminum die-cast member is a member manufactured by die-casting an aluminum alloy, and the shape, size, etc. are not particularly limited. Aluminum alloys for die casting are defined in JIS H 5302: 2006, and examples thereof include ADC12 and ADC10 of Al-Si-Cu based alloys.

  The polymer member is a member having a resin or rubber (including a thermoplastic elastomer) as a main component, and the shape thereof is not particularly limited. For example, a silicone member having a silicone resin or a silicone rubber as a main component is preferable because it is excellent in electrical properties, heat resistance, cold resistance, flame retardancy, and chemical stability.

  The silicone member is produced by curing a composition containing an organopolysiloxane and a crosslinking agent. The composition is, if necessary, a crosslinking accelerator, a crosslinking retarder, a crosslinking assistant, an adhesive component, a scorch inhibitor, an antiaging agent, a softener, a heat stabilizer, a flame retardant, a flame retardant assistant, UV absorption It may contain an agent, a rust inhibitor, a conductive agent, an antistatic agent and the like.

  The organopolysiloxane has at least two crosslinkable functional groups in one molecule, and contains alkenyl group (vinyl group, allyl group etc.) containing organopolysiloxane, hydroxyl group containing organopolysiloxane, (meth) acrylic group containing Organopolysiloxane, isocyanate-containing organopolysiloxane, amino group-containing organopolysiloxane, epoxy group-containing organopolysiloxane and the like.

  As the crosslinking agent, a hydrosilyl crosslinking agent, a sulfur crosslinking agent, a peroxide crosslinking agent and the like can be mentioned. The hydrosilyl crosslinking agent includes hydrosilyl group-containing organopolysiloxane (organohydrogenpolysiloxane) and the like.

  As the adhesive component, a compound having a functional group capable of binding to a hydroxyl group present on the bonding surface of the aluminum die-cast member is desirable. As a functional group, an alkoxy silyl group, a hydrosilyl group, a silanol group etc. are mentioned. For example, as a compound having an alkoxysilyl group, a silane coupling agent may be used. The silane coupling agent is a silane compound having two or more different functional groups in the molecule. As functional groups other than the alkoxy silyl group in a silane coupling agent, a vinyl group, an epoxy group, a styryl group, a (meth) acryl group etc. are mentioned. Specific examples of the silane coupling agent include p-styryltrimethoxysilane, phenyltri (dimethylsiloxy) silane, vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyl Trihydroxysilane etc. are mentioned.

  Hereinafter, each process of the manufacturing method of the composite member of this invention is demonstrated.

[Melting process]
This process is a process of irradiating the laser to the bonding surface of the aluminum die-cast member with the polymer member to melt the surface layer of the bonding surface.

The laser may be a known YAG laser, YVO ₄ laser, rare earth-doped fiber laser, semiconductor laser, fiber laser, or the like. Among them, a fiber laser is preferable in terms of good installation, long life, easy maintenance, and the like, in addition to the fact that it is excellent in light collecting property due to the high quality beam by the output from the optical fiber.

The output of the laser may be adjusted to the extent that the surface layer of the aluminum die-cast member can be melted, for example, if the energy density per unit area and unit time (laser irradiation density) is adjusted to ² J / mm ² or more. Good. It is more effective that the laser irradiation density is 4 J / mm ² or more. On the other hand, from the viewpoint of reducing the thermal damage to the aluminum die-cast member, the irradiation density of the laser is preferably 40 J / mm ² or less, and more preferably 30 J / mm ² or less. When the laser is irradiated at an irradiation density of ² J / mm ² or more, the carbide film formed on the bonding surface can be removed together with the melting of the surface layer.

(1) Removal Step In this step, melting of the surface layer of the bonding surface and removal of the carbide film may be performed simultaneously, but after removing the carbide film in advance, the melting treatment of this step is performed. You may go. Laser processing, plasma processing, etc. may be mentioned as a method of removing the carbide film. For example, the manufacturing method of the composite member of the present invention may have a removing step of irradiating the bonding surface of the aluminum die-cast member with a laser to remove the carbide film existing on the bonding surface before the present step. In this case, the removing step and the melting step do not necessarily have to be performed continuously. The melting step may be performed after a lapse of several hours, several days, etc. after the removal step. The removal process of the carbide film can be performed with a smaller laser irradiation density as compared with the melting process. That is, if only removing the carbide film, it is possible to minimize the thermal damage with a relatively small laser irradiation density. Specifically, the irradiation density of the laser in the removal step is preferably 0.5 J / mm ² or more and less than ² J / mm ² .

If the removal process of the carbide film is performed before the melting process, there are the following two advantages.
(A) If a carbide film is present on the bonding surface, carbon components that can not be removed at the time of melting may be taken into the inside, which may cause corrosion later. Therefore, the risk of corrosion can be reduced by removing the carbide film in advance.
(B) Since the carbide film is not formed uniformly, the method of melting the surface layer may change depending on the presence or absence of the carbide film. For example, when it is easy to melt the portion where the metal is exposed and it is difficult to melt the portion where the carbide film is present, there is a possibility that a homogeneous surface layer can not be obtained. Therefore, removing the carbide film in advance is effective in homogenizing the surface layer.

(2) Modification Step A large number of hydroxyl groups are generated on the bonding surface after the melting step. Here, from the viewpoint of generating a large number of hydroxyl groups on the bonding surface and maintaining a state of high reactivity with the polymer material for a longer time, a modification process is performed to provide hydroxyl groups on the bonding surface after the melting step. May be That is, the manufacturing method of the composite member of the present invention may have, after the present step, a reforming step of irradiating the bonding surface of the aluminum die-cast member with plasma to give a hydroxyl group to the bonding surface.

  When the bonding surface after the melting treatment is irradiated with plasma, chemical bonds of molecules are broken by ions, radicals and the like in the plasma, and the surface is activated to generate hydroxyl groups. Since a large number of hydroxyl groups are generated on the bonding surface by the dry process of plasma irradiation, the hydroxyl groups are unlikely to decrease even with the passage of time, and the state of high reactivity with the polymer material can be maintained for a relatively long time. Therefore, it is possible to firmly bond the aluminum die-cast member to the polymer member even if the integral forming in the next combining step is not continuously performed (it is needless to say that it may be continuously performed) after the reforming step. Can be realized.

  The method of generating plasma is not particularly limited. For example, RF plasma using a radio frequency (RF) power source, microwave plasma using a microwave power source, direct current (DC) pulse plasma, or the like may be employed, and modulation may be applied to the power source. Among them, microwave plasma is preferable because it has a high plasma density, a high processing speed, and little plasma damage on the object to be irradiated. When microwave plasma is employed in the reforming step, many hydroxyl groups can be generated in a short time, which is highly efficient.

  The frequency of the plasma generation power source is not particularly limited. Examples of microwave frequencies include 8.35 GHz, 2.45 GHz, 1.98 GHz, and 915 MHz. 13.56 MHz etc. are mentioned as a frequency of RF. As a frequency of DC, 1-500 kHz etc. are mentioned.

  In the plasma, ions, electrons, and radicals are mixed by ionizing the gas. For example, when plasma is generated in a gas atmosphere containing oxygen, oxygen radicals are generated. The bonding surface can be activated in a relatively short time by the surface adsorption of oxygen radicals and the oxidation reforming action. The gas atmosphere containing oxygen may be air, or may be composed of only oxygen gas, or a mixed gas of oxygen gas and a rare gas or nitrogen gas. As the noble gas, argon, xenon and the like are preferable. For example, in the case where the gas atmosphere containing oxygen is composed of a mixed gas of one or more gases selected from rare gases and nitrogen gas and oxygen gas, the surface adsorption of oxygen radicals and the oxidation reforming action are effectively used. From the viewpoint of the above, it is desirable to set the oxygen gas content to at least 30% when the pressure or volume of the entire mixed gas is 100%. If the oxygen-containing gas atmosphere is made up of only oxygen gas, it is possible to make the best use of the action of radicals, which is effective.

  Irradiation of plasma may be performed under atmospheric pressure or under reduced pressure to a predetermined pressure (atmospheric pressure plasma treatment or vacuum plasma treatment may be performed). Above all, when performed under vacuum, damage to incidental equipment due to ozone or the like generated in plasma can be easily prevented, and the mixing ratio of oxygen gas can be increased. Thereby, the surface adsorption of oxygen radicals and the oxidation reforming action can be exhibited effectively. In addition, the plasma density can be increased to increase the processing speed, and the plasma irradiation range can be easily enlarged to increase the productivity. And, since the plasma density is high, the degree of activation of the bonding surface is increased, and more hydroxyl groups can be generated. Thereby, the state in which the reactivity with the polymer material is high at the bonding surface can be maintained for a longer time. In the case of vacuum plasma treatment, the pressure in the container for generating plasma may be about 1 to 100 Pa.

[Composition process]
This step is a step of integrally molding the polymer material on the bonding surface which has been subjected to the melting treatment and further the modification treatment. The polymer material is a material for forming a polymer member, and is mainly composed of resin or rubber (including a thermoplastic elastomer). For example, when the polymer member is a silicone member, the polymer material is a silicone material. As mentioned above, the silicone material may be prepared from an organopolysiloxane, a crosslinking agent, an adhesive component, and the like.

  This process may be performed by insert molding, for example. That is, an aluminum die-cast member that has finished the melting process (and in some cases the reforming process) is placed in the mold, and a liquid polymer material is injected into the mold so as to contact the bonding surface of the aluminum die-cast member. The polymer material may be cured at a predetermined temperature and pressure. Alternatively, a liquid polymer material may be applied to the bonding surface of the aluminum die-cast member which has been subjected to the melting process (or the modification process as the case may be), and the polymer material is cured at a predetermined temperature and pressure. Good. The polymer material is cured to be a polymer member, and a composite member in which the aluminum die-cast member and the polymer member are firmly bonded can be obtained.

  It is desirable to carry out this process continuously after the melting process because it avoids contamination of the bonding surface and suppresses the reduction of hydroxyl groups. On the other hand, when the reforming process is performed after the melting process, this process may be continuously performed after the reforming process, but several hours, several days, etc. after the reforming process is completed. It may be done after the lapse of time. As described above, according to the modification step, the bonding surface is sufficiently activated, so the generated hydroxyl groups are unlikely to decrease even with time, and the state of high reactivity with the polymer material is maintained for a relatively long time can do. Therefore, even if this process is not performed continuously, the hydroxyl group on the bonding surface and the polymer material can be reacted to achieve strong adhesion. From the viewpoint of securing high adhesion, it is desirable to carry out this step within one week after the reforming step.

  The adhesiveness between the aluminum die-cast member and the polymer member in the obtained composite member may be evaluated by performing a 90 ° peel test defined in JIS K 6256-2: 2013. For example, if the peel strength in the peel test is 4 N / mm or more and cohesive failure occurs, the adhesiveness can be judged to be good.

  The state (degree of activation) of the bonding surface prior to the present step (after the melting step, and in some cases, after the modification step) can be estimated from the magnitude of the water contact angle of the bonding surface. For example, when the water contact angle of the bonding surface is 50 ° or less, sufficient hydroxyl groups are formed on the bonding surface, and it can be considered that the reactivity with the polymer material is high. In the present specification, as the water contact angle, a value measured according to JIS R 3257: 1999 is adopted.

  There is almost no carbide film considered to be a residue of a mold release agent or the like on the bonding surface prior to the present step (after the melting step and optionally after the reforming step). As time passes, a small amount of organic matter suspended in the air adheres to the atmosphere, but the amount of carbon contained at a depth of about 2 to 5 nm from the bonding surface becomes smaller than that in the presence of a carbide film. For example, when the bonding surface before this process is analyzed by X-ray photoelectron spectroscopy (XPS), the number of C atoms is 5% to 30% when the total number of atoms of Al, O, and C is 100%. It is desirable that

  Next, the present invention will be more specifically described by way of examples.

<Production of test pieces>
Example 1
(1) A silicone material was prepared as follows. 1 part by mass of p-styryltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) as an adhesive component is added to 100 parts by mass of liquid silicone rubber (vinyl group-containing dimethylpolysiloxane: manufactured by Gelest, "DMS-V35"), The mixture was mixed for 30 minutes with a planetary mixer. To this mixture, 4 parts by mass of a hydrosilyl crosslinker (hydrosilyl group-containing dimethylpolysiloxane: “HMS-151”, manufactured by Gelest Co.) is added and mixed for another 30 minutes, followed by vacuum degassing to prepare a liquid silicone material. did.

  (2) A rectangular plate-like member (aluminum die-cast member) manufactured by die-casting the ADC 12 of an Al-Si-Cu based alloy was prepared. The size of the plate-like member is 60 mm long, 45 mm short, and 2.0 mm thick.

  First, the entire surface of the plate-like member was subjected to laser processing using a laser oscillator "YLS-2000-CT" manufactured by IPG Photonics Japan Co., Ltd. The conditions of the laser treatment are as follows. Laser spot diameter: about 0.4 mm, moving speed: 100 mm / sec, laser irradiation density: 5.0 J / mm 2. The laser treatment in Example 1 corresponds to the melting step in the present invention. In Example 1, the removal of the carbide film and the melting of the surface layer were simultaneously performed by one laser treatment.

  Next, the plate-like member one hour after the laser treatment was placed in a mold, and the prepared silicone material was injection-molded at a temperature of 140 ° C. and an injection pressure of 0.3 MPa (compounding step). Thus, a test piece in which the silicone member was vulcanized and bonded to a part of one surface of the plate-like member was manufactured. A part of one surface of the plate-like member to which the silicone member is adhered is included in the concept of the bonding surface in the present invention. The manufactured test piece is a reference example in that the removal step is not performed before the melting step. The top view of the manufactured test piece is shown in FIG.

  As shown in FIG. 1, the test piece 1 is composed of a plate-like member 10 and a silicone member 11. The silicone member 11 has a strip shape. The size of the silicone member 11 is 90 mm long, 25 mm short, and 6 mm thick. The left end portion of the silicone member 11 is overlapped and adhered to a part (25 mm × 25 mm area, shown by dotted hatching in FIG. 1) of one surface (upper surface) 100 of the plate-like member 10.

Example 2
Test pieces were produced in the same manner as in Example 1 except that the entire one surface of the same plate-like member as in Example 1 was subjected to two times of laser processing under different conditions. The conditions of the first laser treatment are moving speed: 400 mm / sec, laser irradiation density: 0.8 J / mm 2, and the conditions of the second laser treatment are moving speed: 100 mm / sec, laser irradiation density: 5. It is 0 J / mm2. The first laser treatment corresponds to the removal step in the present invention, and the second laser treatment corresponds to the melting step in the present invention.

  In the second embodiment, a plurality of plate-like members which are similarly laser-processed are manufactured in the same manner, and using these, as described later, the laser-processing is performed immediately after the laser processing (melting step) and every time a predetermined time elapses therefrom. The water contact angle of the finished surface was measured. And the plate-shaped member which measurement completed was sequentially provided to the compounding process.

[Example 3]
A test piece was produced in the same manner as in Example 1 except that the entire surface of the plate-like member was subjected to two times of laser treatment in the same manner as in Example 2 and microwave plasma treatment was further performed under vacuum. The microwave plasma treatment was performed as follows. First, a plate-like member was placed in a vacuum vessel, and the pressure in the vacuum vessel was reduced to 0.5 Pa or less. Next, oxygen gas was supplied into the vacuum vessel to form an oxygen gas atmosphere with a pressure of 10 Pa. In this state, microwave plasma was generated at a frequency of 2.45 GHz and an output power of 2 kW, and the entire surface of the plate-like member subjected to laser treatment was irradiated for 10 seconds. Thus, the one surface was activated to form hydroxyl groups on the surface. The microwave plasma treatment of Example 3 corresponds to the reforming step in the present invention.

  Similarly in the third embodiment, a plurality of plate-like members subjected to laser processing and microwave plasma processing are similarly manufactured, and using these, as described later, immediately after microwave plasma processing (reforming step) and a predetermined time thereafter The water contact angle of the microwave plasma-treated one surface was measured each time Among them, XPS analysis of the same surface was also performed immediately after the microwave plasma treatment. And the plate-shaped member which measurement completed was sequentially provided to the compounding process.

Comparative Example 1
Test pieces were produced in the same manner as in Example 1 except that the entire surface of the same plate-like member as in Example 1 was not laser treated. That is, the silicone material was injection molded into the die-cast plate member.

Comparative Example 2
Test pieces were produced in the same manner as in Example 1 except that the conditions for the laser treatment were changed. The conditions of the laser treatment are moving speed: 400 mm / sec, laser irradiation density: 0.8 J / mm ² . This laser processing corresponds to the removal step in the present invention because the laser irradiation density is low. That is, in Comparative Example 2, a test piece was manufactured without melting the surface layer of one surface (without a melting step).

  Also in Comparative Example 2, a plurality of plate-shaped members which are similarly laser-processed are manufactured, and using these, as described later, the laser-processing is performed immediately after the laser processing (removal step) and each time a predetermined time elapses therefrom. The water contact angle of the finished surface was measured. And the plate-shaped member which measurement completed was sequentially provided to the compounding process.

<Measurement of water contact angle>
About the test piece of Example 2, Example 3, and the comparative example 2, the water contact angle of one side after the process by a laser etc. (before a compounding process) was measured. The water contact angle was measured four times, one hour, one day, and seven days after treatment. The water contact angle was measured according to JIS R 3257: 1999. That is, water with a liquid volume of 2 μl was dropped on one surface of the plate-like member, and the water contact angle within 1 minute after the water was in contact with the one surface was measured.

<Analysis by X-ray photoelectron spectroscopy (XPS)>
With respect to the test piece of Example 3, one surface immediately after the microwave plasma treatment (immediately after the modification step) was subjected to XPS analysis, and the ratio of C atoms, O atoms, and Al atoms present on the surface was examined. For comparison, the untreated side of the test piece of Comparative Example 1 was subjected to XPS analysis to check the proportions of C atoms, O atoms, and Al atoms present on the surface.

<Evaluation of adhesion>
The test pieces of Examples 1 to 3 and Comparative Examples 1 and 2 were subjected to a 90 ° peel test defined in JIS K 6256-2: 2013 to evaluate the adhesion of the silicone member to the plate-like member. As a result of the 90 ° peel test, the case where the peel strength is 4 N / mm or more and cohesive failure is good adhesion (shown by 印 in Tables 1 and 2 below), the peel strength is less than 4 N / mm or the interface The case of peeling was regarded as poor adhesion (indicated by x in the same Table 1 and Table 2). In the case of cohesive failure, the rubber remaining ratio was 100%, and in the case of interfacial peeling, the rubber remaining ratio was calculated by quantifying the rubber adhesion area within a certain range by image analysis using an optical microscope.

<Evaluation result>
Table 1 shows the evaluation results of adhesion in Examples 1 to 3 and Comparative Example 2. In Table 1, adhesion evaluation is a case where a silicone material is integrally molded one hour after treatment with a laser or the like. Table 2 shows the evaluation results of water contact angle and adhesion in Example 2, Example 3 and Comparative Example 2. Table 3 shows the results of XPS analysis of the test pieces of Example 3 and Comparative Example 1. In Table 3, evaluation of the adhesiveness of the test piece of Example 3 is a case where silicone material is integrally molded one hour after microwave plasma processing.

  As shown in Table 1, in the test pieces of Examples 1 to 3 in which the bonding surface was subjected to the melting treatment, the peeling force in the 90 ° peeling test exceeded 6 N / mm, and cohesive failure occurred. Even if the removal treatment and the melting treatment are performed simultaneously (Example 1) or separately (Example 2), in the test piece in which the silicone material is integrally formed (composited) one hour after the melting treatment, adhesion is obtained There was no significant difference in gender. On the other hand, in the test piece of Comparative Example 2 in which the melting process was not performed, the peeling force was less than 4 N / mm and the interfacial peeling was performed.

  As shown in Table 2, in the test piece of Comparative Example 2 in which the fusion treatment of the bonding surface was not performed, the adhesiveness was good only for the composite that was formed immediately after the treatment due to the effect of removing the carbide film. However, other than that, the water contact angle was large and the adhesion was poor. On the other hand, in the test piece of Example 2 in which the melting treatment was performed, the adhesiveness was improved as compared with Comparative Example 2. The reason for this is that, in addition to the activation of the bonding surface by the melting treatment, the grain boundaries are reduced and the surface layer is homogenized, so that the distribution of hydroxyl groups is reduced. In addition, in the test piece of Example 3 in which the bonding surface was melted and then reformed, the water contact angle immediately after the treatment was as small as less than 10 °, and was 50 ° or less even after 7 days, and the adhesion was also good. Met. The smaller the water contact angle, the higher the hydrophilicity, and in the test piece of Example 3, it is presumed that the amount of hydroxyl groups on the surface is large. In addition, in the test piece of Example 2 in which the bonding surface was not subjected to the modification treatment, the adhesion was good except for the compounded 7 days after the melting treatment, but in comparison with the test piece of Example 3 The water contact angle increased. The reason for the increase in the water contact angle is considered to be the formation of streaks of irregularities corresponding to the spot diameter along the scanning direction at the time of laser irradiation.

  As shown in Table 3, according to XPS analysis of the bonding surface immediately after the modification treatment, in the test piece of Example 3, the percentage of C atoms was 30% or less, while the untreated comparative example In the test piece No. 1, the percentage of C atoms exceeded 50%. From this result, it can be seen that the carbide film existing on the bonding surface was removed by the laser treatment. In addition, the adhesiveness of the test piece of the comparative example 1 which has not performed any of a removal process and a melting process was naturally inferior.

  From the above, it is confirmed that when the surface of the aluminum die-cast member is irradiated with a laser to melt the surface layer, the carbide film is removed and the surface layer is homogenized and activated to improve adhesion. It was done. In addition, it has been confirmed that when the bonding surface is irradiated with plasma to give a hydroxyl group, the temporal decrease of the hydroxyl group can be suppressed, and a high reactivity with the polymer material can be maintained for a relatively long time.

  The method of manufacturing a composite member of the present invention is useful as a method of manufacturing various composite members used for electronic control devices such as an engine control unit mounted on a vehicle, electronic devices of small portable terminal devices, and the like.

1: Test piece, 10: Plate-like member (aluminum die-cast member), 11: Silicone member, 100: One surface of plate-like member.

Claims (12)

A method of manufacturing a composite member in which an aluminum die-cast member and a polymer member are combined,
Removing the carbide film existing on the bonding surface by irradiating the bonding surface of the aluminum die-cast member with the polymer member with a laser;
A melting step of irradiating the bonding surface with a laser to melt the surface layer of the bonding surface;
A compounding step of integrally molding a polymer material on the bonding surface;
A method of manufacturing a composite member comprising: The method according to claim 1, wherein an irradiation density of the laser in the melting step is ² J / mm ² or more and 40 J / mm ² or less.   The method for manufacturing a composite member according to claim 1, wherein the irradiation density of the laser in the removing step is smaller than the irradiation density of the laser in the melting step. The method according to any one of claims 1 to 3, wherein the irradiation density of the laser in the removing step is 0.5 J / mm ² or more and less than ² J / mm ² .   The method for producing a composite member according to any one of claims 1 to 4, further comprising a modification step of irradiating the bonding surface with plasma to give a hydroxyl group to the bonding surface after the melting step.   The method of manufacturing a composite member according to claim 5, wherein the irradiation of the plasma in the reforming step is performed in a gas atmosphere containing oxygen. The gas atmosphere containing oxygen comprises only oxygen gas, or a mixed gas of one or more gases selected from rare gas and nitrogen gas and oxygen gas,
The method for producing a composite member according to claim 6, wherein the content ratio of the oxygen gas in the case of comprising the mixed gas is 30% or more when the pressure or volume of the whole mixed gas is 100%.   The method for manufacturing a composite member according to any one of claims 5 to 7, wherein the plasma is a microwave plasma.   The method for manufacturing a composite member according to any one of claims 1 to 4, wherein the melting step and the combining step are performed continuously.   The method for manufacturing a composite member according to any one of claims 5 to 8, wherein the reforming step and the combining step are performed continuously or after leaving a time within one week.   The method for manufacturing a composite member according to any one of claims 1 to 10, wherein a water contact angle of the joining surface before the combining step is 50 ° or less.   When the bonding surface before the combining step is analyzed by X-ray photoelectron spectroscopy, the number of C atoms is 5% or more and 30% or less when the total number of atoms of Al, O, and C is 100%. A method of manufacturing a composite member according to any one of claims 1 to 11.

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