Dry bonding method for non-thermoplastic resin, and base material for dry bonding

Abstract

To provide a dry bonding method for a non-thermoplastic resin and a base material for dry bonding.SOLUTION: In a bonding method for a non-thermoplastic resin according to the present invention, atomic oxygen is radiated to a surface of a non-thermoplastic resin to be bonded, to form an irregular portion on the surface. Irregular portions of the non-thermoplastic resin to be bonded are abutted to each other, and press bonded at 100°C or less. Preferably, the press bonding between the irregular portions is carried out at from 10 to 80°C.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for dry bonding non-thermoplastic resins and a substrate for dry bonding.

Background Art

[0002] Non-thermoplastic resins are difficult to heat-seal, and the addition of foreign substances such as adhesives is required to bond them. Therefore, problems such as poor adhesion due to problems with the bonded part and contamination due to elution of impurities have become issues. As a technique for bonding films without using an adhesive, for example, when bonding polyimide films, a technique of heat-pressing two polyimide films with their surfaces plasma-treated is described in Patent Document 1 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to Patent Document 1, using an internal electrode type plasma generator, glow discharge is performed at a discharge voltage of 1000 V or more, and the surface of the polyimide film is brought into contact with a low-temperature plasma atmosphere. Then, the polyimide films with their surfaces plasma-treated are overlapped, and a film laminate is obtained by heating and pressing at 200°C or more without using an adhesive. Also, it is described that it is desirable to heat and press at 50 kg / cm 2 or more for 5 minutes or more.

[0005] According to the technology described in Patent Document 1, although the use of an adhesive can be avoided, it is necessary to perform hot pressing while heating the resin to a high temperature of 200°C or higher, which causes problems such as a complicated process and problems of chemical substance elution due to high-temperature treatment. Therefore, according to the conventional bonding technology, there are problems such as limited applications and the need for a cleaning process.

[0006] The present invention has been made in view of the problems of the prior art, and an object thereof is to provide a technology capable of joining non-thermoplastic resins without using means such as heating and pressurizing to a high temperature of 200°C or higher without using an adhesive.

Means for Solving the Problems

[0007] The inventors of the present invention have been researching and developing a technology for irradiating atomic oxygen (AO) on the surface of non-thermoplastic resins, and have reached the present invention by applying this technology.

[0008] The present invention is an invention made to solve the above problems, and as means, has the following configuration. (1) The dry bonding method of non-thermoplastic resins according to this embodiment is characterized in that atomic oxygen is irradiated on the surface of the non-thermoplastic resin to be joined to form uneven portions on the surface, and the uneven portions of the non-thermoplastic resin to be joined are abutted against each other and pressure-bonded at 100°C or lower. (2) In the dry bonding method of non-thermoplastic resins according to (1) above, it is preferable to perform the pressure bonding of the uneven portions at 10°C to 80°C.

[0009] When atomic oxygen is irradiated on the surface of a non-thermoplastic resin, fine uneven portions are generated on the surface. When the non-thermoplastic resins are pressure-bonded through these uneven portions, the non-thermoplastic resins are effectively joined at the portions where the uneven portions are abutted against each other, and a joint with high joint strength can be achieved. When the surface of a non-thermoplastic resin is irradiated with atomic oxygen, the surface of the non-thermoplastic resin is partially scraped and fine uneven portions are formed. In these fine uneven portions, the chains of the polymer resin constituting the non-thermoplastic resin are partially cut, and it is considered that uneven portions in a highly reactive state are formed. Therefore, by butting and pressing the uneven portions in a highly reactive state against each other, a joint portion joined with high strength can be obtained. When butting and pressing the uneven portions against each other for joining, it is preferably carried out at a temperature in the range of 10°C to 80°C. If the temperature during pressing is too high, bubbles such as air trapped in the butting portion of the uneven portions expand, weakening the joint portion, and thus a high joint strength cannot be obtained.

[0010] (3) In the dry joining method of the non-thermoplastic resin according to the above (1) or (2), when irradiating with atomic oxygen, the atomic oxygen irradiation amount (AO fluence) per unit area is 5×10 20 atoms / cm 2 or more and 8×10 20 atoms / cm 2 or less.

[0011] When forming uneven portions by irradiating with atomic oxygen, by setting the number of atomic oxygen to 5×10 20 atoms / cm 2 or more and 8×10 20 atoms / cm 2 or less, fine uneven portions desirable for joining the non-thermoplastic resin can be formed.

[0012] (4) In the dry joining method of the non-thermoplastic resin according to the above (1) or (2), a polyimide resin film can be used as the non-thermoplastic resin.

[0013] When joining non-thermoplastic resins, if a polyimide resin film is used, fine uneven portions suitable for joining can be surely formed by irradiation with atomic oxygen, and the resin films can be joined through a joint portion having excellent joint strength.

[0014] (5) In the dry bonding method of the non-thermoplastic resin according to (4) above, it is preferable to form atomic oxygen irradiated uneven portions having a height of 2 μm or more and 4 μm or less, a width of 0.5 μm or more and 1 μm or less, and an aspect ratio of 4 or more, and to butt-join the atomic oxygen irradiated uneven portions and perform pressure bonding so that the bonding width is 5 μm or less.

[0015] If the atomic oxygen irradiated uneven portions having a height of 2 μm or more and 4 μm or less, a width of 0.5 μm or more and 1 μm or less, and an aspect ratio of 4 or more and 8 or less are formed on the film of the polyimide resin, a joint portion having high joint strength can be formed by butting and pressurizing the uneven portions.

[0016] (6) The base material for dry bonding of the non-thermoplastic resin according to this embodiment has atomic oxygen irradiated uneven portions having a height of 2 μm or more and 4 μm or less, a width of 0.5 μm or more and 1 μm or less, and an aspect ratio of 4 or more and 8 or less.

[0017] If it is a dry bonding base material having atomic oxygen irradiated uneven portions having a height of 2 μm or more and 4 μm or less, a width of 0.5 μm or more and 1 μm or less, and an aspect ratio of 4 or more and 8 or less, the dry bonding base materials can be joined with high joint strength by butting and pressurizing the atomic oxygen irradiated uneven portions of the dry bonding base material.

[0018] When the surface of the non-thermoplastic resin is irradiated with atomic oxygen, the surface of the non-thermoplastic resin is partially scraped and fine atomic oxygen irradiated uneven portions are generated. In these fine atomic oxygen irradiated uneven portions, it is considered that the chains of the polymer resin constituting the non-thermoplastic resin are partially cut, and uneven portions in a highly reactive state are generated. Therefore, by butting and pressurizing the atomic oxygen irradiated uneven portions in a highly reactive state, a joint portion joined with high strength can be obtained.

[0019] (7) In the base material for dry bonding of the non-thermoplastic resin according to (6) above, it is preferable that a part of the molecular chains of the polymer resin constituting the non-thermoplastic resin is cut in the atomic oxygen irradiated uneven portions. (8) In the base material for dry bonding of the non-thermoplastic resin according to (6) above, it is preferable that the non-thermoplastic resin is polyimide and a part of the molecular chain of polyimide is cut in the atomic oxygen irradiation uneven portion.

[0020] The atomic oxygen irradiation uneven portion obtained by irradiating the surface of the non-thermoplastic resin with atomic oxygen is considered to be an atomic oxygen irradiation uneven portion in a highly reactive state in which a part of the molecular chain of the polymer resin chain is partially cut. Therefore, by butting and pressing the atomic oxygen irradiation uneven portions in a highly reactive state, a joint portion joined with high strength can be obtained.

Effect of the Invention

[0021] According to the present invention, it is possible to provide a technique capable of dry-bonding non-thermoplastic resins without using an adhesive and without using means such as heating and pressing at a high temperature of 200 °C or higher. In addition, since the technique of the present invention does not require the addition of foreign substances such as adhesives, there is no problem of contamination due to the addition of foreign substances, and since it is not necessary to heat to a high temperature of 200 °C, there is also no problem of chemical substance elution due to high-temperature treatment.

Brief Description of the Drawings

[0022]

Figure 1

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Mode for Carrying Out the Invention

[0023] 「First Embodiment」 Hereinafter, regarding the method for joining non-thermoplastic resins according to the first embodiment of the present invention, an example will be given and described in detail, but the present invention is not limited to the embodiments described below. FIG. 1 is an explanatory diagram showing a film 1 of a non-thermoplastic resin used in the method for joining non-thermoplastic resins according to the first embodiment of the present invention, and shows a state in which atomic oxygen is being irradiated onto the surface thereof by an atomic oxygen irradiation device 2. As an example, the film 1 of the non-thermoplastic resin can use a polyimide film or the like. As polyimide films, films made of various polyimides such as DuPont's trade name Kapton, DuPont's trade name VespeI, Kanegafuchi Chemical Industry Co., Ltd.'s trade name Apical, UBE Industries, Ltd.'s trade name Upilex, UBE Industries, Ltd.'s trade name Upi-mol, Mitsui Chemicals, Inc.'s trade name Aurum, and Mitsui Chemicals, Inc.'s LARC-TPI are known. In the present embodiment, a film made of any conventionally known polyimide may be applied.

[0024] In addition, as non-thermoplastic resins applicable to the joining method of the present invention, polyester resins, polyurethane resins, urea resins, melamine resins, epoxy resins, phenol resins, furan resins, vinyl ester resins, benzoxazine resins, cyanate ester resins, etc. may be applied.

[0025] The atomic oxygen irradiation device 2 has, as an example, a vacuum chamber for generating atomic oxygen, and is equipped with a rotary pump and a molecular pump connected to the vacuum chamber, and by these, it has a vacuum facility capable of evacuating to about 5.0×10 -5 Pa. Further, it includes an oxygen cylinder and a pulse valve capable of introducing molecular oxygen pulses into the vacuum chamber, a laser emission device for introducing pulsed carbon dioxide laser light into the interior of the vacuum chamber, and an optical system provided inside the vacuum chamber. The atomic oxygen irradiation device 2, as an example, introduces oxygen gas into the interior of the aforementioned vacuum chamber in pulses, imparts energy to the oxygen gas by a pulsed carbon dioxide laser, generates and accelerates atomic oxygen, and can irradiate the film disposed inside the vacuum chamber with atomic oxygen. In FIG. 1(a), for simplicity of illustration, only the configuration in which atomic oxygen is irradiated from the atomic oxygen irradiation unit 3 onto the film 1 is shown in a simplified manner.

[0026] By imparting energy from a laser to oxygen gas, atomic oxygen can be generated and accelerated, and the velocity of the atomic oxygen can be adjusted as appropriate by adjusting the time interval between gas injection and laser irradiation. As an example, the atomic oxygen irradiation device 2 can adopt the above-described configuration, but any other generally known atomic oxygen generation device having another structure may be used. In any case, as long as the device can irradiate the film 1 with atomic oxygen under the conditions described later, the device configuration is not limited.

[0027] When irradiating the film 1 with atomic oxygen using the atomic oxygen irradiation device 2, the atomic oxygen irradiation amount per unit area (AO fluence) is preferably 5×10 20 atoms / cm 2 or more. Also, the atomic oxygen irradiation amount is preferably 8×10 20 atoms / cm 2 or less. For example, when the film 1 is 25 μm thick, if the film is irradiated with atomic oxygen in an atomic oxygen number exceeding 8×10 20 atoms / cm 2 , the film may be damaged or disappear, and it may become impossible to use it as a film to be joined.

[0028] If the above-described atomic oxygen irradiation is performed on two films 1 to be joined, the two films 1 are taken out of the device, and the atomic oxygen irradiation surfaces are abutted against each other as shown in Fig. 1(b), and the films 1, 1 are evenly pressurized and pressure-bonded. For even pressurization, a pressurizing device such as a pressurizing device in which rolls shown schematically are arranged above and below so that pressure can be applied in the direction of the arrow shown in Fig. 1(b) can be used. The pressurizing device is not limited to a press device in which rolls are arranged above and below, and may be a press device that presses with a pressure plate or the like from above and below.

[0029] When the film 1 is, for example, a long strip wound in a roll shape, a laminate in which the long and strip-shaped films are continuously adhered can be formed by continuously supplying the roll-shaped film between the upper and lower rolls of the upper and lower roll type pressurizing device and pressurizing at room temperature. When the film 1 is a long strip wound, for example, in a roll shape, in the previous process, a film unwinding device and a winding device for the roll-shaped strip can be accommodated inside the vacuum chamber of the atomic oxygen irradiation device 2. By continuously irradiating one side of the film continuously unwound from the unwinding device with atomic oxygen and winding the film around the winding device after irradiation, even a film in the form of a long strip can be handled.

[0030] The temperature during pressure bonding can be normal temperature. However, if heated to a high temperature, as will be described later, the bonding strength will be inferior. Therefore, the temperature during pressure bonding is desirably normal temperature or above normal temperature, for example, 100 °C or lower. The temperature during pressure bonding is desirably in the range of 10 °C to 80 °C, more desirably in the range of 25 °C to 60 °C, and most preferably 25 °C to 40 °C.

[0031] When the surface of the film 1 made of a non-thermoplastic resin is irradiated with atomic oxygen at about 5×10 20 atoms / cm 2 as an example, fine atomic oxygen irradiation uneven portions 1a are formed on the surface of the film 1 as shown in the photograph of FIG. 7 showing the results of the examples described later. From the analysis results of the example shown in FIG. 7, these atomic oxygen irradiation uneven portions 1a can be described as uneven portions in which many protrusions having a height of about 2 μm, a width of about 0.5 μm, and an aspect ratio of about 4 are formed. In the present embodiment, when irradiating the surface of the film 1 with atomic oxygen, it is preferable to irradiate so that the atomic oxygen irradiation amount (AO fluence) is 5×10 20 atoms / cm 2 or more.

[0032] When the surface of the film 1 is irradiated with atomic oxygen at about 5×10 20 atoms / cm 2 as shown in FIG. 7. Therefore, it is preferable to irradiate with atomic oxygen of 5×10 20 atoms / cm 2 or more and 8×10 20 atoms / cm 2 or less. In this case, the aspect ratio of the atomic oxygen irradiated uneven portion shown in FIG. 7 is 10 or less, for example, in the range of about 4 or more and 8 or less. Therefore, under the above-described conditions, it is preferable that the atomic oxygen irradiated uneven portion has projections with a height of 2 μm or more and 4 μm or less, a width of 0.5 μm or more and 1 μm or less, and an aspect ratio of 4 or more and 8 or less. Since the atomic oxygen irradiated uneven portions with the above-described projection heights are joined, it is preferable that the joining width is 5 μm or less.

[0033] Note that, in FIG. 7, in addition to the fine uneven portions, mushroom-shaped projections that are clearly larger than the uneven portions are formed. These are projections formed by the portions that remained without being eroded as a result of the resin around them being scraped off by atomic oxygen starting from foreign matters and impurities contained in a minute amount in the film 1. These mushroom-shaped projections are not included in the concept of the fine atomic oxygen irradiated uneven portions defined in the present embodiment. Although it is preferable that there are no mushroom-shaped projections generated due to foreign matters and impurities adhering to the surface of the film 1, even if there are some to a certain extent as in the example shown in FIG. 7, it does not matter.

[0034] As illustrated in FIG. 7, two films 1 each having fine uneven portions 1a on the surface can be joined by pressing them against each other at normal temperature or within the above-described temperature range with the uneven portions 1a facing each other. As shown in FIG. 1(b), when the surfaces of films 1 having the same area are joined and laminated, a laminated film S in which two films 1 are laminated can be obtained. As shown in FIG. 1(b), the laminated film S in which the surfaces irradiated with atomic oxygen to form fine atomic oxygen irradiated uneven portions 1a are laminated together becomes a laminated film integrated with high joining strength. Therefore, when a peel test for peeling the film 1 constituting the laminated film S is performed, a laminated film S showing excellent tensile strength can be obtained. In the present embodiment, since the films 1 can be joined to each other, each film 1 can be described as a base material for dry joining.

[0035] In the uneven portion 1a formed by irradiating atomic oxygen as described above, there are portions where the molecular chains of the polymer resin constituting the non-thermosetting resin such as polyimide resin are cut on the surface of the film 1. As a result, it is considered that the surface has a large number of fine uneven portions 1a where intermolecular forces act. It can be estimated that the irradiation of atomic oxygen on the resin surface cuts and oxidizes the molecular chains on the polyimide resin surface, resulting in a more unstable surface state than the unirradiated polyimide resin surface. Therefore, when the film 1s are pressed together with the atomic oxygen irradiated uneven portions 1a abutting each other, not only do the uneven portions 1a become entangled, but hydrogen bonds and the like are generated and entanglement also occurs at the molecular level. As a result, it is considered that the film 1s are joined with a high bonding force.

[0036] In the embodiment shown in FIG. 1, the films 1 of the same area made of non-thermoplastic resin are joined, but the non-thermoplastic resin used for joining may have any shape such as a plate, a tape, or a rod. Also, the joining portion is not limited to the entire surface, and it may be a part of non-thermoplastic resins such as a plate, a tape, or a rod.

Example

[0037] A plurality of films (diameter: 20 mm, thickness: 25 μm) made of DuPont's product name Kapton were used, and atomic oxygen was irradiated onto the entire surface of each film. For the irradiation of atomic oxygen, a laser-excited atomic oxygen generator was used. This device includes a vacuum chamber equipped with a rotary pump and a molecular pump, an oxygen cylinder and a pulse valve capable of introducing molecular oxygen pulses into the vacuum chamber. Further, it includes a laser light emitting device for introducing pulsed carbon dioxide laser light into the interior of the vacuum chamber, and an optical system provided inside the vacuum chamber. Further, since the erosion rate of Kapton film with respect to atomic oxygen is known (3.0×10 ―24 cm 3 / atom), the atomic oxygen irradiation amount can be evaluated by evaluating the mass loss associated with the irradiation.

[0038] Using the aforementioned atomic oxygen generator, the irradiation dose of atomic oxygen was adjusted for a plurality of films as shown in Table 1 below, and a plurality of films were prepared. The atomic oxygen irradiation dose was 1 - 2×10 20 (AO fluence: atoms / cm 2 ), 1.5×10 20 (atoms / cm 2 ), 1.8×10 20 (atoms / cm 2 ), 4×10 20 (atoms / cm 2 ), 5×10 20 (atoms / cm 2 ), for a total of six levels. Two films with the same atomic oxygen irradiation dose were prepared. The atomic oxygen irradiation surfaces were overlapped to form a laminated film, and the top and bottom surfaces of the laminated film were sandwiched between PET (polyethylene terephthalate) films to form a laminate. This laminate was pressed using a pressing device equipped with two pressure rolls. The gap between the two pressure rolls was set to 0, and the aforementioned laminate was passed between the upper and lower rolls and pressed at room temperature to obtain a room temperature press sample. Also, two films with their atomic oxygen irradiation surfaces overlapped were heated to 300 °C on a hot plate and then pressed using a pressing device to produce a heated press sample.

[0039] A peel test was performed on the room temperature press sample and the heated press sample prepared as described above. The peel test was performed on a film sample cut into strips (width: 5 mm, length: 25 mm). Figure 2 shows a state where one mending tape 5 is attached to one side of the cut sample (laminated film S), and the other mending tape 5 is attached to the other side of the cut sample. A test piece was prepared by attaching a tissue (protective sheet) 6 to the end of one mending tape 5 and attaching a tissue (protective sheet) 6 to the end of the other mending tape 5. The ends of the mending tapes 5, 5 with each protective sheet 6 attached were pulled in a direction away from each other, and a peel test (tensile test) was performed to determine the peel strength of the laminated film S. For the tensile test, a tabletop tensile compression tester (MCT-1150) manufactured by FORT tester was used. Tensile tests were performed on a total of 10 test pieces, and the results of obtaining the maximum tensile strength (N / cm) and the average tensile strength (N / cm) are shown in Table 1 below. Table 1 below also shows the irradiation dose of atomic oxygen for the film used for each test piece.

[0040]

Table 1

[0041] As shown in Table 1, for the test pieces tested at room temperature and 300 °C with an atomic oxygen irradiation dose (AO fluence) of 1 to 4×10 20 (atoms / cm 2 ), neither the maximum tensile strength nor the average tensile strength improved significantly. However, for the test pieces with an atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ), both the maximum tensile strength and the average tensile strength improved significantly. The fact that the maximum tensile strength of the laminated film obtained by setting the atomic oxygen irradiation dose to 5×10 20 (atoms / cm 2 ) is at most 1.3 N / cm means that it is joined with a sufficiently high strength.

[0042] On the other hand, for the heat press sample at 300 °C, even for the test piece with an atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ), it is the same as that with an atomic oxygen irradiation dose of 1 to 4×10 20 (atoms / cm 2Only the same tensile strength as that of the test piece with the atomic oxygen irradiation dose of From the above, by setting the atomic oxygen irradiation dose to 5×10 20 (atoms / cm 2 ) and applying pressure at room temperature, it was found that a laminated film with excellent peel strength can be produced.

[0043] Figure 3 shows the details of the peel test results of the room temperature press sample with the atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ) shown in Table 1. Figure 4 shows the details of the peel test results of the heat press sample with the atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ) shown in Table 1. Figure 5 shows a comparison of the details of the peel test results for five room temperature press samples treated with various atomic oxygen irradiation doses shown in Table 1. From the results shown in Table 1 and Figures 3 to 5, when joining non-thermoplastic resin films at room temperature, irradiating the bonding surface with atomic oxygen at an atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ) or more was found to be effective in obtaining an excellent bonding structure.

[0044] Figure 6 shows the FE-SEM observation image of the polyimide resin film before atomic oxygen irradiation, and Figure 7 shows the FE-SEM observation image of the surface of the polyimide resin film after irradiation with an atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ). As shown in Figure 7, on the film surface with an atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ), a large number of fine atomic oxygen irradiation uneven parts (protrusion structures) with protrusions having a height of about 2 μm or less, a width of about 0.5 μm or less, and an aspect ratio of about 4 were formed. These fine atomic oxygen-irradiated uneven portions can be regarded as fine uneven portions that resulted from the polymer resin on the film surface being scraped off by atomic oxygen and a part of the polymer chains (polyimide chains) of the polymer resin being cut.

[0045] The atomic oxygen irradiation dose was 5×10 20 (atoms / cm 2 ). The reason for the good adhesion between the films can be regarded as the result of the above-mentioned uneven portions adhering to each other and forming a joint. In addition, in Fig. 7, apart from the fine uneven portions of the aforementioned size, a plurality (five in Fig. 7) of larger mushroom-shaped protrusions can be confirmed. These protrusions are protrusions formed by a part of the film surface remaining as a result of the surrounding portions excluding these foreign substances and impurities being scraped off by the irradiation of atomic oxygen when foreign substances and impurities were present on the film surface. It can be determined that these protrusions do not particularly contribute to the improvement of the adhesion between the films.

[0046] Fig. 8 shows the results of cross-sectional observation by FE-SEM (Schottky field emission type scanning electron microscope: JSM-7800, 2 kV) of the joint of a room temperature press sample with an atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ). Fig. 8(a) shows a sample in which the cross-section of the joint was generated by a microtome, and Fig. 8(b) shows a sample in which the cross-section of the joint was generated by ion milling. Fig. 9 shows the results of cross-sectional observation by FE-SEM (Schottky field emission type scanning electron microscope: JSM-7800, 2 kV) of the joint of a heated press sample with an atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ) and heated and pressed at 300°C. Fig. 9(a) shows a sample in which the cross-section of the joint was generated by a microtome, and Fig. 9(b) shows a sample in which the cross-section of the joint was generated by ion milling.

[0047] From the comparison between Fig. 8 and Fig. 9, with an atomic oxygen irradiation dose of 5×1020 (atoms / cm 2 ) Even for a sample bonded together, when heated to a high temperature of 300 °C during the pressure application for bonding, the bonding strength tends to decrease. From the comparison of the results shown in Fig. 8(b) and the results shown in Fig. 9(b), it can be seen that when heated to 300 °C, the bubbles present in the bonded part expand due to heating, elongate in the thickness direction of the film, and form elongated cavities. From the analysis of these figures, it can be presumed that the bubbles thermally expanded due to heating, thereby reducing the tensile strength of the joint. From the above, after forming fine atomic oxygen irradiation unevenness on the surface with an atomic oxygen irradiation dose of 5×10 20 (atoms / cm 2 ), it was found that the film bonded at room temperature without heating showed excellent bondability.

[0048] Figs. 10 and 11 show the results of observing the peeled surface of the room temperature press sample and the peeled surface of the heat press sample after the aforementioned peel test by FE-SEM (Schottky field emission type scanning electron microscope: JSM-7800, 2 kV). When peeling a film having a joint where the uneven parts are in close contact, as a result of pulling the joint on the peeled surface, it is considered that there are many structures in which the convex parts are elongated. In Fig. 10, as a result of the tension, a structure having many parts extending to the fine uneven parts was observed, but in Fig. 11, as a result of the tension, there were few traces of parts that seemed to have extended to the fine uneven parts. From this, it was found that the room temperature press sample presented a peeled surface that could be presumed to have formed a good joint due to the uneven parts.

Explanation of Reference Signs

[0049] 1... film, 1a... atomic oxygen irradiation unevenness, 2... atomic oxygen irradiation device, 3... irradiation part.

Claims

1. A method for dry joining of non-thermoplastic resins, comprising irradiating the surfaces of the non-thermoplastic resins to be joined with atomic oxygen to form irregularities on the surfaces, and butting the irregularities of the non-thermoplastic resins to be joined together and pressurizing them at 100°C or less.

2. 2. The method for dry bonding of non-thermoplastic resins according to claim 1, wherein the pressure bonding between the projections and recesses is carried out at a temperature of 10°C to 80°C.

3. When irradiating the atomic oxygen, the atomic oxygen irradiation amount per unit area (AO fluence) is set to 5×10 ２０ atoms / cm ２ Above 8 x 10 ２０ atoms / cm ２ 3. The method for dry bonding of non-thermoplastic resins according to claim 1, wherein the following is performed:

4. 3. The method for dry bonding of non-thermoplastic resins according to claim 1, wherein the non-thermoplastic resin is a polyimide resin film.

5. The method for dry bonding of non-thermoplastic resins according to claim 4, characterized in that an atomic oxygen irradiated uneven portion having a height of 2 μm to 4 μm, a width of 0.5 μm to 1 μm, and an aspect ratio of 4 to 8 is formed, and the atomic oxygen irradiated uneven portions are butted together and pressure bonded to each other, thereby making the bonding width 5 μm or less.

6. A non-thermoplastic resin substrate for dry bonding having an atomic oxygen irradiated uneven portion with a height of 2 μm to 4 μm, a width of 0.5 μm to 1 μm, and an aspect ratio of 4 to 8.

7. 7. The substrate for dry bonding according to claim 6, wherein a molecular chain of a polymer resin constituting the non-thermoplastic resin is partially cut in the uneven portion irradiated with atomic oxygen.

8. 7. The substrate for dry bonding according to claim 6, wherein the non-thermoplastic resin is polyimide, and a molecular chain of the polyimide is partially cut in the uneven portion irradiated with atomic oxygen.

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