Laminate and manufacturing method thereof

Abstract

To provide a laminate in which different resin members are strongly boned without the intervention of adhesives, and a method for producing the same.SOLUTION: A laminate 1 comprises a first resin member 2 and a second resin member 3 bonded to each other, where the first and second resin members contain different resins from each other. The laminate has a bonded part 4 at an interface between the first resin member and the second resin member, where the bonded part is formed from the mixture of a resin contained in the first resin member and a resin contained in the second resin member. The bonded part has a peak which does not originate from either the first resin member or the second resin member in a spectrum measured by infrared spectroscopy.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laminate in which different types of resin members are bonded together without the use of an adhesive, and a method for producing the same. [Background technology]

[0002] Known techniques for joining different types of resin members include, for example, joining with an adhesive and welding.

[0003] However, adhesive bonding can cause gradual elution or volatilization of adhesive components, which can lead to problems with contamination from adhesives, particularly in the medical field, where safety and cleanliness are important. Furthermore, the adhesive itself can deteriorate over long periods of use, making weather resistance problematic, particularly for outdoor applications. Furthermore, when a solvent-based adhesive is used, there is a problem of residual solvent. Furthermore, some types of resins cannot be bonded with adhesives.

[0004] Furthermore, there are concerns that the welding method may cause deterioration of the resin due to localized heating, and the welding method is suitable for resins that can be welded at relatively low temperatures, so the resins that can be used are limited.

[0005] Recently, resin bonding techniques using electron beam irradiation have been proposed (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-135980 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-232446 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the inventors have found through their investigation that bonding of different types of resin members by electron beam irradiation may result in a weak adhesive strength that is not practical.

[0008] The present disclosure has been made in view of the above-mentioned problems, and aims to provide a laminate in which different types of resin members are firmly bonded without the use of an adhesive, and a method for manufacturing the same. [Means for solving the problem]

[0009] To solve the above-mentioned problems, the present inventors conducted extensive research and found that dissimilar resin members can be firmly joined by subjecting the surface of one of the resin members to plasma treatment, irradiating it with an electron beam, leaving it for a predetermined time, irradiating the surface of the other resin member with an electron beam, and then thermocompression bonding the two resin members. Furthermore, the inventors found that when dissimilar resin members are joined using the above method, the compatibility of the components of each resin member is increased at the interface between the dissimilar resin members, forming a region where the components of each resin member are mixed, and the components of each resin member react to form chemical bonds such as covalent bonds. The present disclosure has been completed based on the above findings.

[0010] That is, one embodiment of the present disclosure provides a laminate in which a first resin member and a second resin member containing different resins are joined together, and the laminate has a joint at the interface between the first resin member and the second resin member where the resin contained in the first resin member and the resin contained in the second resin member are mixed, and the joint has a peak in a spectrum measured by infrared spectroscopy that is not attributable to either the first resin member or the second resin member.

[0011] Another embodiment of the present disclosure provides a method for manufacturing a laminate that joins a first resin member and a second resin member that contain different resins, the method comprising: a first step of subjecting one surface of the first resin member to plasma treatment and then irradiating it with an electron beam, followed by leaving it for a predetermined period of time; a second step of irradiating one surface of the second resin member with an electron beam; and a third step of aligning the surface of the first resin member that has been subjected to the plasma treatment and irradiated with the electron beam and the surface of the second resin member that has been irradiated with the electron beam, and thermocompression bonding the first resin member and the second resin member together. [Effects of the Invention]

[0012] The present disclosure has an effect of providing a laminate in which different types of resin members are firmly bonded without the use of an adhesive, and a method for manufacturing the same. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view illustrating a laminate of the present disclosure. [Figure 2] 1A to 1C are process diagrams illustrating a method for producing a laminate according to the present disclosure. [Figure 3] 1 is a schematic cross-sectional view illustrating a laminate of the present disclosure. [Figure 4] FIG. 1 is a schematic diagram illustrating a plasma processing apparatus. [Figure 5] 1 shows STEM images of laminates of an example and a comparative example. [Figure 6] 1 shows an optical microscope image, an AFM image, and an IR spectrum of the laminate of Example 1. [Figure 7] 1 shows an optical microscope image, an AFM image, and an IR spectrum of the laminate of Comparative Example 1. [Figure 8] 1 shows an AFM image and an IR spectrum of the laminate of Example 1. [Figure 9] 1 shows an AFM image and an IR spectrum of the laminate of Comparative Example 1. [Figure 10] 1 is a graph showing the profiles of peak intensities or intensity ratios in the IR spectra of the laminates of Example 1 and Comparative Example 1. [Figure 11] 1 shows the results of STEM-EDX analysis of the laminate of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present inventors conducted extensive research into the joining of dissimilar resin members and first attempted to join dissimilar resin members by electron beam irradiation, i.e., by irradiating the surfaces of each member with an electron beam and then thermocompressing the two members together. However, it was found that this method could result in weak adhesive strength between dissimilar resin members depending on the resin combination. In addition to electron beam irradiation, plasma treatment is also known as a surface treatment technique for resin members. Therefore, the present inventors next attempted a combination of electron beam irradiation and plasma treatment to join dissimilar resin members by subjecting the surface of one of the dissimilar resin members to plasma treatment, irradiating the surface of the other member with an electron beam, and then thermocompressing the two resin members together. It was found that this method increased the adhesive strength between dissimilar resin members. However, further research revealed that, while increasing the plasma treatment intensity tends to increase the adhesive strength between dissimilar resin members, increasing the plasma treatment intensity can result in uneven plasma irradiation, which can result in uneven adhesion and, in fact, decrease the adhesive strength between dissimilar resin members. They then discovered that by combining electron beam irradiation and plasma treatment to bond dissimilar resin components, plasma treatment is applied to the surface of one of the resin components, followed by irradiation with electron beams, a predetermined time is allowed, the surface of the other resin component is irradiated with electron beams, and then the two resin components are thermocompression bonded, it is possible to firmly bond dissimilar resin components while suppressing the occurrence of uneven adhesion due to plasma treatment.

[0015] Furthermore, it is assumed that electron beam irradiation or plasma treatment generates radicals on the surfaces of two resin components, thereby forming chemical bonds, particularly covalent bonds, between the resins contained in the two resin components. However, when plasma treatment is performed on the surface of one of the dissimilar resin components, and the surface of the other resin component is irradiated with an electron beam, and the two resin components are then thermocompressed together, chemical bonds, particularly covalent bonds, may not be formed between the resins contained in the two resin components. However, it has been found that when plasma treatment is performed on the surface of one of the resin components, and then electron beam irradiation is performed, a predetermined time is allowed, the surface of the other resin component is irradiated with an electron beam, and the two resin components are then thermocompressed together, chemical bonds, particularly covalent bonds, are formed between the resins contained in the two resin components.

[0016] In addition, in a method in which the surface of one of two different resin components is subjected to plasma treatment, the surface of the other resin component is irradiated with an electron beam, and then the two resin components are thermocompressed together, chemical bonds, particularly covalent bonds, may not be formed between the resins contained in the two resin components. This is thought to be because the radicals generated by plasma treatment tend to have a short lifespan.

[0017] Furthermore, in the case of a method in which the surface of one of dissimilar resin members is subjected to a plasma treatment, then irradiated with an electron beam, and then left for a predetermined time, the surface of the other resin member is irradiated with an electron beam, and then the two resin members are thermocompression-bonded, the reason why dissimilar resin members can be firmly joined is not clear, but it is thought that the plasma treatment of one of the resin members increases the compatibility of the resins contained in the two resin members at the interface between the dissimilar resin members, which contributes to adhesion. Specifically, it is thought that the plasma treatment of one of the resin members changes the chemical and physical properties of the surface of the resin member, for example, by breaking bonds, introducing functional groups, or forming fine irregularities on the surface of the resin member, thereby increasing the compatibility of the resins contained in the two resin members at the interface between the dissimilar resin members. It is presumed that at the interface between different types of resin components, the compatibility of the resins contained in the two resin components becomes high, making it easier for the resins contained in the two resin components to diffuse into each other, and making it easier to form an area where the resins contained in the two resin components are mixed.

[0018] The present disclosure was completed based on these findings.

[0019] The laminate and its manufacturing method according to the present disclosure will be described below. However, the present disclosure can be implemented in many different embodiments, and should not be construed as being limited to the description of the embodiments exemplified below. Furthermore, in order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each component more schematically than in the embodiments, but these are merely examples and do not limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with respect to the previous drawings are given the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0020] In this specification, when expressing the arrangement of a component on top of another component, the terms "above" or "below" are used, unless otherwise specified, to include both the case where another component is arranged directly above or below a component so as to be in contact with the component, and the case where another component is arranged above or below a component with another component in between.

[0021] Furthermore, in this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely based on differences in name. For example, the term "sheet" is used to include members also known as films and plates.

[0022] A. Laminate The laminate of the present disclosure is a laminate in which a first resin member and a second resin member containing different resins are joined together, and has a joint at the interface between the first resin member and the second resin member where the resin contained in the first resin member and the resin contained in the second resin member are mixed, and the joint has a peak in a spectrum measured by infrared spectroscopy that is not attributable to either the first resin member or the second resin member.

[0023] The laminate of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic cross-sectional view showing an example of a laminate of the present disclosure. As illustrated in Fig. 1, the laminate 1 of the present disclosure is formed by joining a first resin member 2 and a second resin member 3 containing different resins, and has a joint 4 at the interface between the first resin member 2 and the second resin member 3, where the resin contained in the first resin member 2 and the resin contained in the second resin member 3 are mixed. Although not shown, the joint 4 has a peak that is not derived from either the first resin member 2 or the second resin member 3 in a spectrum measured by infrared spectroscopy.

[0024] In the present disclosure, a first resin member and a second resin member containing different resins are directly bonded. Generally, bonding different resin members is difficult. This is because the resins contained in the different resin members have low compatibility. If the compatibility of the resins contained in the different resin members is poor, the resins contained in the two resin members are unlikely to mix at the interface between the two resin members, making it difficult to form a region where the resins are mixed. In contrast, in the present disclosure, a bonded portion is formed at the interface between the first resin member and the second resin member, where the resin contained in the first resin member and the resin contained in the second resin member are mixed. Therefore, it can be said that the resin contained in the first resin member and the resin contained in the second resin member have good compatibility at the interface between the first resin member and the second resin member. In other words, even if the compatibility between the resin contained in the first resin member and the resin contained in the second resin member is low, it can be said that the compatibility between the resin contained in the first resin member and the resin contained in the second resin member is good at the interface between the first resin member and the second resin member.

[0025] In addition, in the present disclosure, the bonded portion has a peak in a spectrum measured by infrared spectroscopy that is not attributable to either the first or second resin member, which means that a chemical bond, particularly a covalent bond, is formed between the resin contained in the first resin member and the resin contained in the second resin member.

[0026] Generally, it is believed that compatibility, chemical bonding, etc. contribute to adhesion.

[0027] Therefore, in the present disclosure, by providing a joint at the interface between the first and second resin members where the resins contained in the first and second resin members are mixed (i.e., the resins contained in the first and second resin members are highly compatible with each other at the interface between the first and second resin members), and by providing a peak at the joint that is not attributable to either the first or second resin member in a spectrum measured by infrared spectroscopy (i.e., a chemical bond, particularly a covalent bond, is formed between the resins contained in the first and second resin members), the first and second resin members can be directly joined without an adhesive, thereby improving the adhesive strength between the first and second resin members. Even when the resins contained in the first and second resin members are poorly compatible with each other, the first and second resin members can be firmly joined.

[0028] 2(a) to 2(e) are process diagrams illustrating an example of a method for manufacturing a laminate according to the present disclosure. First, as shown in FIG. 2(a), one surface of a first resin member 2 is irradiated with plasma 11 to perform plasma treatment. Then, as shown in FIG. 2(b), one surface of the first resin member 2 is further irradiated with an electron beam 12, and a predetermined time is allowed to pass. Furthermore, as shown in FIG. 2(c), one surface of a second resin member 3 is irradiated with an electron beam 13. Next, as shown in FIG. 2(d), the first resin member 2 is subjected to plasma treatment, and the surface irradiated with the electron beam faces the surface irradiated with the electron beam of the second resin member 3, and the first resin member 2 and the second resin member 3 are thermocompression-bonded. This results in a laminate 1 in which the first resin member 2 and the second resin member 3, each containing a different resin, are bonded together, and the laminate 1 has a joint 4 at the interface between the first resin member 2 and the second resin member 3, where the resin contained in the first resin member 2 and the resin contained in the second resin member 3 are mixed.

[0029] In the present disclosure, the surface of the first resin member is subjected to plasma treatment, and then irradiated with an electron beam. After a predetermined time, the surface of the second resin member is irradiated with an electron beam, thereby generating radicals on the surfaces of the first and second resin members. As a result, chemical bonds, such as covalent bonds or hydrogen bonds, can be formed between the resins contained in the first and second resin members. Specifically, it is believed that radicals are generated on the surfaces of the first and second resin members, and the radicals generated on the surfaces of the first and second resin members bond with each other to form covalent bonds, or that the generated radicals react with oxygen in the atmosphere to generate functional groups such as carbonyl groups, carboxy groups, and hydroxyl groups, which then form hydrogen bonds.

[0030] Although welding methods such as heat sealing are also used as a technique for joining different types of resin components, welding methods do not form covalent bonds between the resins contained in the different types of resin components.

[0031] Another possible method for joining dissimilar resin components by a combination of electron beam irradiation and plasma treatment is to subject the surface of one of the dissimilar resin components to plasma treatment, irradiate the surface of the other resin component with an electron beam, and then thermocompress the two resin components together. However, the inventors' investigations have revealed that this method may not result in the formation of chemical bonds, particularly covalent bonds, between the resins contained in the two resin components.

[0032] In addition, a comparison of bonding dissimilar resin members using a combination of plasma treatment and electron beam irradiation with bonding dissimilar resin members using electron beam irradiation revealed that bonding dissimilar resin members using a combination of plasma treatment and electron beam irradiation had higher adhesive strength. While the reason for this is unclear, it is believed that plasma treatment of one resin member increases the compatibility of the resins contained in the two resin members at the interface between the dissimilar resin members, contributing to adhesion. Therefore, it is presumed that the resins contained in the two resin members are more likely to diffuse into each other at the interface between the dissimilar resin members, making it easier for a region where the resins contained in the two resin members are mixed to form.

[0033] Furthermore, as described above, plasma treatment of the first resin member can increase the compatibility between the resin contained in the first resin member and the resin contained in the second resin member at the interface between the first resin member and the second resin member. Therefore, if plasma treatment is performed on the surface of the first resin member, and then electron beam irradiation is performed, a predetermined time is allowed, the surface of the second resin member is irradiated with electron beams, and then thermocompression bonding is performed, it is presumed that the heating during thermocompression bonding makes it easier for the resin contained in the first resin member and the resin contained in the second resin member to diffuse into each other, making it easier to form an area where the resin contained in the first resin member and the resin contained in the second resin member are mixed.

[0034] The configuration of the laminate of the present disclosure will be described below.

[0035] 1. First resin member and second resin member In the present disclosure, the first resin member and the second resin member contain different resins.

[0036] In this specification, the resin contained in the first resin member may be referred to as the first resin, and the resin contained in the second resin member may be referred to as the second resin.

[0037] The resins contained in the first resin member and the second resin member are not particularly limited as long as they can form a chemical bond between the first resin contained in the first resin member and the second resin contained in the second resin member. Among these, a covalent bond is preferable as the chemical bond. This is because the formation of a covalent bond between the first resin and the second resin can improve the adhesive strength between the first resin member and the second resin member.

[0038] Furthermore, it is preferable that the first resin contained in the first resin member and the second resin contained in the second resin member have low compatibility. Direct bonding of dissimilar resin members with low compatibility is difficult. This is because the components of each resin member are unlikely to diffuse into each other at the interface between dissimilar resin members with low compatibility. In contrast, in the present disclosure, as described above, the surface of one resin member is subjected to plasma treatment, and then irradiated with an electron beam, after which a predetermined time is allowed to pass. The surface of the other resin member is then irradiated with an electron beam, and the two resin members are then thermocompression bonded. This increases the compatibility of the surfaces of the two resin members, making it easier for the components of each resin member to diffuse into each other at the interface between the two resin members. Therefore, even if the compatibility between the first resin contained in the first resin member and the second resin contained in the second resin member is low, the first resin member and the second resin member can be firmly bonded.

[0039] Here, the solubility parameter (SP value) is used as an index of compatibility. When the difference in SP value is large, the compatibility is low, and when the difference in SP value is small, the compatibility is high. Specifically, the difference between the SP value of the first resin and the SP value of the second resin is preferably 0.1 or more, more preferably 0.5 or more, and particularly preferably 2 or more. The upper limit of the difference in SP value is not particularly limited, but is about 15. The present disclosure is useful when the difference in SP value is large, such as in the above range.

[0040] The SP value referred to in this specification means the value shown in the SP value table described on pages 15 and 189-190 of the "Plastic Data Book" published by the Industrial Research Institute (published December 1, 1999). For resins not shown in the SP value table, the solubility parameter can be determined from the calculated value of the cohesive energy density.

[0041] The first and second resins are preferably a combination of resins with low compatibility, such as the following combinations: Fluorine-based resin / resin that contains virtually no fluorine Fluorine resin / polyolefin resin Fluorine resin / polyvinyl chloride resin Polyester resin / Polyolefin resin Polyvinyl chloride resin / Polyolefin resin Polyamide resin / Polyolefin resin Polyvinyl alcohol resin / polyolefin resin

[0042] In particular, when the surface of the first resin member is subjected to plasma treatment, further irradiated with an electron beam, and then irradiated with an electron beam, it is preferable that the first resin be a fluororesin and the second resin be a resin that is substantially free of fluorine. That is, it is preferable that the first resin member contains a fluororesin and the second resin member contains a resin that is substantially free of fluorine. Fluorine-based resins and resins that are substantially free of fluorine tend to be less compatible. Furthermore, resin members that contain fluororesin typically have very low surface tension and do not have functional groups, such as hydroxyl groups, that participate in hydrogen bonding on their surfaces. Therefore, an adhesive is required when joining a resin member that contains a fluororesin and a resin member that contains a resin that is substantially free of fluorine. As such, it is difficult to directly join a resin member that contains a fluororesin and a resin member that contains a resin that is substantially free of fluorine. In contrast, according to the present disclosure, even with such a combination of the first resin member and the second resin member, the first resin member and the second resin member can be firmly joined.

[0043] In particular, when the surface of the first resin member is subjected to plasma treatment, and then irradiated with an electron beam, and the surface of the second resin member is irradiated with an electron beam, if the first resin member contains a fluorine-based resin and the second resin member contains a resin that is substantially free of fluorine, it is believed that the plasma treatment of the first resin member removes fluorine from the surface of the first resin member, thereby improving the compatibility between the fluorine-based resin and the resin that is substantially free of fluorine. Therefore, the present invention is useful in the case of the above-mentioned combination of the first resin member and the second resin member.

[0044] However, simply irradiating the surface of the first resin member with an electron beam does not remove fluorine from the surface of the first resin member. Therefore, when the first resin member contains a fluorine-based resin and the second resin member contains a resin that is substantially free of fluorine, it is difficult to firmly bond the first resin member and the second resin member by a method in which the surfaces of the first resin member and the second resin member are irradiated with an electron beam and then the first resin member and the second resin member are thermocompression-bonded.

[0045] Furthermore, in the case of the above-mentioned combinations of polyester-based resin / polyolefin-based resin, polyvinyl chloride-based resin / polyolefin-based resin, polyamide-based resin / polyolefin-based resin, and polyvinyl alcohol-based resin / polyolefin-based resin, if the surface of the first resin member is subjected to plasma treatment and then irradiated with an electron beam, and the surface of the second resin member is irradiated with an electron beam, the second resin can be a polyolefin-based resin and the first resin can be a resin other than a polyolefin-based resin.

[0046] Examples of fluorine-based resins include polytetrafluoroethylene resin (PTFE), perfluoroalkoxy resin (PFA), copolymer resin of tetrafluoroethylene and hexafluoropropylene (FEP), copolymer resin of tetrafluoroethylene, perfluoroalkyl vinyl ether, and hexafluoropropylene (EPE), copolymer resin of tetrafluoroethylene and ethylene (ETFE), polychlorotrifluoroethylene resin (PCTFE), copolymer resin of ethylene and chlorotrifluoroethylene (ECTFE), vinylidene fluoride resin (PVDF), and vinyl fluoride resin (PVF). Among these, polychlorotrifluoroethylene resin (PCTFE) is preferred. When the laminate of the present disclosure is used as a packaging material, polychlorotrifluoroethylene resin (PCTFE) is suitable for packaging materials due to its high moisture resistance.

[0047] A resin that is substantially free of fluorine is a resin that contains substantially no fluorine atoms in its molecular structure. Here, "substantially free of fluorine" means that the fluorine content in the resin is 5% by mass or less. In particular, the fluorine content in the resin is preferably 3% by mass or less, and more preferably 0% by mass. In other words, a resin that does not contain fluorine is preferred.

[0048] Examples of such resins that are substantially free of fluorine include polyolefin resins, polyester resins, polyamide resins, polystyrene resins, polycarbonate resins, polyimide resins, polyphenylene sulfide resins, polyethersulfone resins, polyacrylonitrile resins, polyvinyl alcohol resins, polyvinyl acetate resins, polyvinyl chloride resins, polyvinylidene chloride resins, acrylic resins, urethane resins, etc. Mixtures of these resins can also be used.

[0049] The polyolefin resin may be a linear polyolefin resin or a cyclic polyolefin resin. Examples of the linear polyolefin resin include polyethylenes such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene; polypropylene; polymethylpentene; and copolymers thereof. A mixture of polypropylene and low-density polyethylene or a mixture of polypropylene and high-density polyethylene can also be used. Among these, polyethylene and polypropylene are preferred because of their high versatility.

[0050] Examples of polyester resins include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate.

[0051] Examples of polyamide resins include nylon 6, nylon 12, nylon 66, nylon 612, nylon 6 / 66 copolymer, nylon 6 / 12 copolymer, polymetaxylylene adipamide (nylon MXD6), and the like.

[0052] Examples of polystyrene resins include polystyrene, styrene-ethylene-butylene-styrene block copolymers, and styrene-isoprene-styrene block copolymers.

[0053] Among the above combinations, it is particularly preferred that the first resin be a fluororesin and the second resin be a polyolefin-based resin. That is, it is particularly preferred that the first resin member contain a fluororesin and the second resin member contain a polyolefin-based resin. Fluorine-based resins and polyolefin-based resins tend to be less compatible with each other. Furthermore, the surface of a resin member containing a fluororesin typically has very low surface tension, and the surfaces of resin members containing a fluororesin and resin members containing a polyolefin-based resin lack functional groups, such as hydroxyl groups, that participate in hydrogen bonding. Therefore, an adhesive is required when joining a resin member containing a fluororesin and a resin member containing a polyolefin-based resin. Thus, it is difficult to directly join a resin member containing a fluororesin and a resin member containing a polyolefin-based resin. In contrast, according to the present disclosure, even with such a combination of a first resin member and a second resin member, the first resin member and the second resin member can be firmly joined.

[0054] As described above, in particular, when the surface of the first resin member is subjected to plasma treatment, and then irradiated with an electron beam, and the surface of the second resin member is irradiated with an electron beam, if the first resin member contains a fluorine-based resin and the second resin member contains a polyolefin-based resin, it is believed that the compatibility between the fluorine-based resin and the polyolefin-based resin is improved by removing fluorine from the surface of the first resin member by the plasma treatment of the first resin member. Therefore, the present invention is useful in the case of the above-mentioned combination of the first resin member and the second resin member.

[0055] Furthermore, as described above, when the first resin member contains a fluorine-based resin, fluorine is removed from the surface of the first resin member by plasma treatment of the first resin member, and therefore it is preferable that the amount of fluorine contained in the first resin member decreases in the thickness direction of the first resin member from the inside of the first resin member toward the surface of the first resin member on the joining side.

[0056] The amount of fluorine contained in the first resin member can be measured, for example, by using STEM-Energy Dispersive X-ray Spectroscopy (STEM-EDX) using a scanning transmission electron microscope (STEM). Specific measurement conditions are as follows: Acceleration voltage: 30.0 kV Emission current: 10μA Probe current: High Magnification: 20,000x or 30,000x WD:8mm Tilt: 0° Detector element area: 100mm 2 Windowless

[0057] Furthermore, at least one of the first resin and the second resin may be a thermoplastic resin. When the laminate of the present disclosure is used as a packaging material, one of the first resin member and the second resin member can be a thermally welded layer, i.e., at least one of the first resin member and the second resin member can be a thermoplastic resin. In the above case, one of the first resin member and the second resin member can be a thermally welded layer, and the other resin member can be a layer other than the thermally welded layer, such as an outer layer, a barrier layer, an antistatic layer, an anti-corrosion layer, a light stabilizing layer, an ultraviolet absorbing layer, or an antioxidant layer. In particular, when the surface of the first resin member is plasma-treated and then irradiated with an electron beam, and the surface of the second resin member is irradiated with an electron beam, it is preferable that the second resin member be a thermally welded layer and the first resin member be a layer other than the thermally welded layer. For example, if the first resin member contains a fluorine-based resin and the second resin member contains a polyolefin-based resin or a polyvinyl chloride-based resin, the first resin member can be a layer other than the above-mentioned thermal welding layer, and the second resin member can be the thermal welding layer.

[0058] Furthermore, the first resin member and / or the second resin member may contain various additives, such as a light stabilizer, an ultraviolet absorber, an antioxidant, a filler, and a lubricant, as needed.

[0059] The first resin member and the second resin member may be in the form of, for example, a film or a sheet, or may be a molded product.

[0060] When the first resin member and the second resin member are films or sheets, they may be stretched in a uniaxial or biaxial direction.

[0061] 2.Joint part The joint in the present disclosure is located at the interface between the first resin member and the second resin member, and is a region where the first resin contained in the first resin member and the second resin contained in the second resin member are mixed. In addition, the joint has a peak that is not attributable to either the first resin member or the second resin member in a spectrum measured by infrared spectroscopy.

[0062] In the present disclosure, the bonded portion is formed by subjecting the surface of the first resin member to plasma treatment, irradiating it with an electron beam, allowing a predetermined time, irradiating the surface of the second resin member with an electron beam, and then thermocompression bonding the first and second resin members together. The bonded portion is a region where the first resin contained in the first resin member and the second resin contained in the second resin member have diffused into each other, i.e., a region where the first resin contained in the first resin member and the second resin contained in the second resin member have mixed at the molecular level.

[0063] Here, the presence of the bonding portion can be confirmed, for example, by observing the cross section of the laminate using a scanning transmission electron microscope (STEM). A specific method for observing the cross section of the laminate is described below. First, the entire laminate is embedded and fixed, and then stained. Ruthenium tetroxide can be used as the staining agent. Next, sections are prepared to obtain the cross section of the laminate. An ultramicrotome EM UC7 manufactured by Leica Microsystems can be used to prepare the sections. Thereafter, the cross section of the laminate is observed using a scanning transmission electron microscope (STEM). The scanning transmission electron microscope (STEM) that can be used is an SU8000 or SU9000 manufactured by Hitachi High-Technologies Corporation. The conditions for observation can be TE mode, accelerating voltage: 30 kV, and emission current: 10 μA.

[0064] The thickness of the bonding portion is not particularly limited as long as it is thick enough to obtain the desired adhesive strength between the first resin member and the second resin member. Specifically, the maximum thickness of the bonding portion can be 10 nm to 10 μm, and may be 50 nm to 5 μm, and particularly 100 nm to 2 μm. As long as the maximum thickness of the bonding portion is within the above range, sufficient adhesive strength can be obtained.

[0065] Here, the maximum thickness of the joint can be measured, for example, by observing the cross section of the laminate using a scanning transmission electron microscope (STEM). The method for observing the cross section of the laminate using a scanning transmission electron microscope (STEM) can be the same as the method described above. Furthermore, as will be described later, when the interface between the first resin member and the second resin member at the joint has an uneven shape, the maximum thickness of the joint can be the maximum height Rz. The maximum height Rz can be measured using a method in accordance with JIS B0601:2013.

[0066] In addition, it is preferable that the interface between the first resin member and the second resin member has an uneven shape at the joint. In the present disclosure, since the surface of the first resin member is subjected to plasma treatment, the plasma treatment on the first resin member changes, for example, the chemical properties or physical properties of the surface of the first resin member, specifically, bonds are broken, functional groups are introduced, or fine unevenness is formed on the surface of the first resin member, so that the interface between the first resin member and the second resin member tends to have an uneven shape.

[0067] In the present disclosure, the interface between the first resin member and the second resin member has an uneven shape, which can increase the adhesive strength between the first resin member and the second resin member. The reason for this is not clear, but it is thought to be as follows: The uneven shape of the interface between the first resin member and the second resin member increases the contact area between the first resin member and the second resin member; the uneven shape increases the contact area between the first resin member and the second resin member, which makes it easier to form chemical bonds between the first resin member and the second resin member; and the uneven shape of the interface between the first resin member and the second resin member creates a so-called anchor effect.

[0068] The presence of the uneven shape can be confirmed, for example, by observing the cross section of the laminate with a scanning transmission electron microscope (STEM). The method for observing the cross section of the laminate with a scanning transmission electron microscope (STEM) can be the same as the method described above.

[0069] The height of the uneven shape is not particularly limited as long as it is a height that can obtain the desired adhesive strength between the first resin member and the second resin member. Specifically, the average height of the uneven shape can be 10 nm to 10 μm, and more preferably 50 nm to 5 μm, and particularly preferably 100 nm to 2 μm. By having the average height of the uneven shape within the above range, the adhesive strength between the first resin member and the second resin member can be effectively improved.

[0070] Here, the average height of the uneven shape can be referred to as the average height Rc, which can be measured by a method in accordance with JIS B0601:2013.

[0071] The height of the uneven shape can be adjusted, for example, by adjusting the conditions of the plasma treatment of the first resin member, etc. Specifically, the height of the uneven shape tends to increase as the intensity of the plasma treatment increases.

[0072] Furthermore, since the uneven shape can be formed by performing a plasma treatment on the surface of the first resin member, the uneven shape is usually a non-uniform uneven shape.

[0073] Furthermore, in a spectrum measured by infrared spectroscopy, the bonding portion has a peak that is not attributable to either the first resin member or the second resin member. This confirms that a chemical bond is formed between the first resin contained in the first resin member and the second resin contained in the second resin member. The chemical bond is preferably a covalent bond. That is, the bonding portion preferably has a covalent bond between an atom contained in the first resin member and an atom contained in the second resin member. This is because the adhesive strength between the first resin member and the second resin member can be increased.

[0074] The fact that the above-mentioned joint has a peak that does not originate from either the first resin member or the second resin member in the spectrum measured by infrared spectroscopy can be confirmed by comparing the IR spectrum of the above-mentioned joint with the IR spectrum of the above-mentioned first resin member and the IR spectrum of the above-mentioned second resin member.

[0075] In the spectrum measured by infrared spectroscopy, the peaks possessed by the joint that are not attributable to either the first resin member or the second resin member may be peaks attributable to chemical bonds, particularly covalent bonds, that may be formed between the first resin contained in the first resin member and the second resin contained in the second resin member, and may vary depending on the types of the first resin and the second resin, but examples include peaks attributable to COC, COOC, COF, etc.

[0076] Here, whether the bonded portion has a peak not attributable to either the first resin member or the second resin member in a spectrum measured by infrared spectroscopy can be confirmed by measuring a cross section of the laminate by AFM-based infrared spectroscopy (AFM-IR). The AFM-IR measurement can be performed using, for example, a nanoIR manufactured by Anasys Instruments.

[0077] The measurement positions on the cross section of the laminate can be determined by observing the cross section of the laminate with a scanning transmission electron microscope (STEM) to confirm the positions of the first resin member, the joint, and the second resin member.

[0078] 3.Laminate The laminate of the present disclosure may be in the form of, for example, a film or a sheet, a molded product, or a structure. When the laminate of the present disclosure is a molded product, for example, the laminate can be produced as a film or a sheet and then molded to obtain a molded product. Figure 3(a) shows an example in which the laminate 1 of the present disclosure is a molded product. Furthermore, when the laminate of the present disclosure is a structure, for example, it may be one in which a first resin member 2 and a second resin member 3 are arranged on at least a portion of the surface of a resin molded product 21, as shown in Figure 3(b), or one in which a first resin member 2 and a second resin member 3 are arranged between two resin molded products 21, 22, as shown in Figure 3(c), or one in which the first resin member 2 and the second resin member 3 are molded products and the molded products, the first resin member 2 and the second resin member 3, are joined, as shown in Figure 3(d), or one in which one of the first resin member and the second resin member is a molded product and the other is a film or sheet, and the other resin member, which is a film or sheet, is arranged on at least a portion of the surface of one of the resin members, which is a molded product.

[0079] The laminate of the present disclosure is suitable for applications where the use of adhesives is undesirable or limited, such as packaging for pharmaceuticals, medical devices, cosmetics, food, etc., and medical devices such as syringes and tubes.

[0080] B. Manufacturing method of laminate The method for manufacturing a laminate disclosed herein is a method for manufacturing a laminate that joins a first resin member and a second resin member that contain different resins, and includes a first step of subjecting one surface of the first resin member to plasma treatment and then irradiating it with an electron beam, followed by leaving it for a predetermined period of time; a second step of irradiating one surface of the second resin member with an electron beam; and a third step of aligning the surface of the first resin member that has been subjected to the plasma treatment and irradiated with the electron beam and the surface of the second resin member that has been irradiated with the electron beam, and thermocompression bonding the first resin member and the second resin member together.

[0081] 2(a) to 2(e) are process diagrams showing an example of a method for producing a laminate according to the present disclosure. Note that, as Figs. 2(a) to 2(e) have been described above in the section "A. Laminate," further description here will be omitted.

[0082] In the present disclosure, as described in the above section "A. Laminate," the surface of the first resin member is subjected to plasma treatment, and then irradiated with an electron beam, after which a predetermined time is allowed to pass, the surface of the second resin member is irradiated with an electron beam, and then the first resin member and the second resin member are thermocompression bonded together, thereby making it possible to firmly bond the first resin member and the second resin member together.

[0083] In addition, in the present disclosure, by combining plasma treatment and electron beam irradiation as a surface treatment for the first resin member, it is possible to increase the adhesive strength between the first resin member and the second resin member while suppressing the occurrence of uneven adhesion due to plasma treatment.

[0084] The method for producing a laminate according to the present disclosure will be described below.

[0085] 1. First resin member and second resin member The first resin member and the second resin member in the present disclosure have been described in detail above in the section "A. Laminate 1. First resin member and second resin member," so a description thereof will be omitted here.

[0086] 2.First step In the first step of the present disclosure, one surface of the first resin member is subjected to plasma treatment, and then irradiated with an electron beam, followed by leaving the surface for a predetermined period of time.

[0087] (1) Plasma treatment The gas used in the plasma treatment is adjusted appropriately depending on the type of resin contained in the first resin member. Examples of the gas include non-reactive gases such as argon and helium, and reactive gases such as nitrogen, oxygen, and hydrogen. Mixtures of these gases can also be used. For example, when the resin contained in the first resin member is a fluorine-based resin, such as polychlorotrifluoroethylene resin (PCTFE), argon gas is preferably used.

[0088] The plasma treatment may be, for example, a low-temperature plasma treatment or a high-temperature plasma treatment, or may be, for example, an atmospheric pressure plasma treatment or a vacuum plasma treatment.

[0089] The conditions for the plasma treatment are adjusted appropriately depending on the type of resin contained in the first resin member. For example, if the plasma treatment intensity is too low, the desired adhesive strength may not be obtained. On the other hand, if the plasma treatment intensity is too high, uneven plasma irradiation may occur, resulting in uneven adhesion between the first resin member and the second resin member, and the first resin member may be damaged or deformed or discolored, resulting in a poor appearance.

[0090] (2) Electron beam irradiation The irradiation energy of the electron beam is adjusted appropriately depending on the type of resin contained in the first resin member. In particular, it is preferable that the irradiation energy of the electron beam is low. By using a low irradiation energy, deterioration of the first resin member can be suppressed and radicals can be generated more efficiently on the surface of the first resin member, thereby achieving a stronger bond.

[0091] The acceleration voltage of the electron beam can be, for example, 50 kV to 70 kV, and the absorbed dose of the electron beam can be, for example, 50 kGy to 900 kGy.

[0092] As the electron beam irradiation device, a conventionally known device can be used, such as a curtain-type electron irradiation device (LB1023, manufactured by i-Electron Beam Co., Ltd.) or a line-irradiation-type low-energy electron beam irradiation device (EB-ENGINE, manufactured by Hamamatsu Photonics Co., Ltd.).

[0093] When irradiating with an electron beam, it is preferable to keep the oxygen concentration at 100 ppm or less. Irradiating with an electron beam in the presence of oxygen generates ozone, which has a negative impact on the environment and may cause the surface of the first resin member to react with the ozone, resulting in changes in its properties. To achieve an oxygen concentration of 100 ppm or less, the first resin member is irradiated with an electron beam in a vacuum or in an inert gas atmosphere such as nitrogen or argon. For example, an oxygen concentration of 100 ppm or less can be achieved by filling the electron beam irradiation device with nitrogen.

[0094] In the present disclosure, in the first step, a predetermined time is allowed to pass after the electron beam irradiation. This increases the adhesive strength between the first resin member and the second resin member. The reason for this is unclear, but it is thought to be as follows: When the surface of the first resin member is irradiated with an electron beam, radicals are generated near the surface of the first resin member. At this time, the generated radicals react to generate other radicals. These other radicals on the surface of the first resin member may bond with radicals on the surface of the second resin member to form covalent bonds. For example, when carbon radicals are generated near the surface of the first resin member, the generated carbon radicals react with oxygen in the atmosphere to generate peroxide radicals. The peroxide radicals on the surface of the first resin member can then bond with carbon radicals on the surface of the second resin member to form covalent bonds. In this way, radicals react over time to generate other radicals, and these other radicals may contribute to the formation of a covalent bond between the first resin contained in the first resin member and the second resin contained in the second resin member.Therefore, by leaving a predetermined time after irradiation with the electron beam, it is possible to sufficiently generate the above-mentioned other radicals, making it easier to form a covalent bond between the first resin contained in the first resin member and the second resin contained in the second resin member.

[0095] The predetermined time may be any time sufficient to generate the other radicals, and may be adjusted appropriately depending on the types of the first resin contained in the first resin member and the second resin contained in the second resin member. Specifically, the time may be 6 hours or more, or may be 12 hours or more. The upper limit of the time is not particularly limited, but may be, for example, 48 hours or less, or may be 36 hours or less. If the time is too short, it may be difficult to generate the other radicals sufficiently.

[0096] 3.Second process In the second step of the present disclosure, one surface of the second resin member is irradiated with an electron beam.

[0097] The electron beam irradiation can be the same as the electron beam irradiation in the first step, and therefore a description thereof will be omitted here.

[0098] In the present disclosure, it is preferable to perform thermocompression bonding of the first resin member and the second resin member in the third step immediately after irradiating one surface of the second resin member with an electron beam in the second step, because this increases the adhesive strength between the first resin member and the second resin member.

[0099] 4.Third step In the third step of the present disclosure, the plasma treatment is performed on the first resin member, the surface irradiated with the electron beam is placed opposite the surface irradiated with the electron beam of the second resin member, and the first resin member and the second resin member are thermally pressed together.

[0100] The method for thermocompression bonding the first resin member and the second resin member is not particularly limited, and examples thereof include a method using a heated roller, heat pressing, and heat lamination.

[0101] The heating temperature during thermocompression bonding should be sufficient to sufficiently bond the first resin member and the second resin member, and is adjusted appropriately depending on the type of the first resin contained in the first resin member and the second resin contained in the second resin member, the heating time, pressure, etc. (described later). The heating temperature can be, for example, near the melting points of the first resin contained in the first resin member and the second resin contained in the second resin member, or may be equal to or lower than the melting points. In particular, the heating temperature is preferably equal to or lower than the melting points. If the heating temperature is too low, the first resin member and the second resin member may not be sufficiently bonded. If the heating temperature is too high, the radicals generated on the surfaces of the first resin member and the second resin member in the first and second steps may be deactivated, which may prevent the first resin member and the second resin member from being firmly bonded.

[0102] The heating time during thermocompression bonding should be sufficient to sufficiently bond the first resin member and the second resin member, and is adjusted appropriately depending on the heating temperature, the pressure described below, the type of the first resin contained in the first resin member and the second resin contained in the second resin member, etc. For example, the heating time can be 0.1 seconds or more and 1 minute or less.

[0103] The pressure during thermocompression bonding should be sufficient to sufficiently bond the first resin member and the second resin member, and is adjusted appropriately depending on the heating temperature, heating time, the type of the first resin contained in the first resin member and the second resin contained in the second resin member, etc. For example, the pressure can be 0.1 MPa or more and 0.5 MPa or less. Note that by increasing the pressure, the heating temperature can be reduced.

[0104] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Example]

[0105] The present disclosure will be described in more detail below with reference to examples and comparative examples.

[0106] (Preparation of resin parts) A polychlorotrifluoroethylene resin (PCTFE) film (DF-0050C1, manufactured by Daikin Industries, Ltd., thickness 50 μm) was prepared as a resin member containing a fluorine-based resin. A polypropylene resin (PP) film (Zelas 7025, manufactured by Mitsubishi Chemical Corporation) was formed into a film with a thickness of 70 μm by an inflation method to prepare a polyolefin-based resin member.

[0107] [Reference examples 1~4] (Plasma treatment) The plasma processing apparatus used was a roll-to-roll type plasma processing apparatus shown in Fig. 4. The plasma processing apparatus shown in Fig. 4 includes a chamber 111, a film supply unit 112 and a film take-up unit 113 arranged in the chamber 111, a mask 152 and a magnetic field generation unit 160 inside the chamber 111, and a processing gas supply unit 140 that supplies a processing gas for plasma processing into the chamber 111.

[0108] Of these, film supply unit 112 includes supply roller 112a around which resin film 151 is wound and which supplies resin film 151. Furthermore, film take-up unit 113 includes take-up roller 113a around which plasma-treated resin film 150 is wound and which takes up resin film 150. Furthermore, a rotatable main roll 114 is disposed between film supply unit 112 and film take-up unit 113. Resin film 151 is wound around the surface of this main roll 114, and the resin film 151 on this main roll 114 is subjected to plasma treatment. Furthermore, a plurality of guide rolls 116 are provided between film supply unit 112 and main roll 114 and between main roll 114 and film take-up unit 113 to guide resin film 151 from film supply unit 112 to film take-up unit 113. Film supply section 112, film winding section 113, main roll 114, and guide roll 116 constitute a roll-to-roll film transport device 115. An exhaust pump 117 that evacuates the chamber 111 via a connecting pipe 118 is connected to chamber 111. A valve 119 that adjusts the degree of vacuum (pressure) in chamber 111 is provided on connecting pipe 118.

[0109] Furthermore, the processing gas supply unit 140 has a gas nozzle 134 that sprays processing gas into the chamber 111, gas supply pipes 144, 145, and 146 that supply the processing gas, and processing gas reservoirs 141, 142, and 143 that store the processing gas. The gas supply pipes 144, 145, and 146 are provided with mass flow controllers (MFCs) 147, 148, and 149, respectively, that control the flow rates of the gases.

[0110] Furthermore, a magnetic field generation unit 160 including a magnet 161 as used in a sputtering apparatus is provided at a position facing the opening of the mask 152 in the chamber 111. A high-frequency power supply is connected to the main roll 140. By introducing a processing gas, adjusting the pressure in the chamber 111, and introducing high-frequency power, plasma P is generated. By installing the magnetic field generation unit 160 and introducing high-frequency power to the main roll 140, a region with a high plasma density is formed near the resin film 151, and plasma treatment is performed. A partition wall 165 is provided in the chamber 111. This partition wall 165 serves to prevent the generated plasma P from spreading to the film supply unit 112 and the film winding unit 113 side and to prevent deposits due to plasma treatment from accumulating on the film supply unit 112 and the film winding unit 113 side.

[0111] On the surface of the PCTFE film, while introducing argon gas at a flow rate of 200 sccm and a pressure of 8 Pa using the above-described roll-to-roll type plasma processing apparatus, plasma treatment was performed at an output of 370 W while changing the film conveyance speed to 0.05 m / min, 0.15 m / min, and 0.45 m / min. Note that the slower the conveyance speed, the stronger the plasma treatment intensity, and the faster the conveyance speed, the weaker the plasma treatment intensity.

[0112] [[ID=P8]](Evaluation) Regarding the plasma-treated surface of the PCTFE film, using an X-ray photoelectron analyzer (Axis-NOVA, manufactured by KRATOS), detection of elements present on the film surface was performed. The measurement conditions were as follows. The results are shown in Table 1. Note that the unit of the numerical values of the elements in the table is atomic%. <XPS Measurement Conditions> [[ID=P13]] Measurement area: 300 μm × 700 μm X-ray used: AlKα ray Acceleration voltage: 15 kV

[0113] [Table 1]

[0114] XPS measurements showed that the proportions of C and O atoms increased and the proportions of F and Cl atoms decreased in the PCTFE film as the plasma treatment intensity increased, indicating that fluorine and chlorine were removed from the surface of the PCTFE film by the plasma treatment.

[0115] [Comparative Examples 1 to 3] (Preparation of laminate) A 300 mm wide PCTFE film was passed through the roll-to-roll plasma treatment device described above, the chamber was closed, and the pressure was reduced to 0.01 Pa or less. Then, argon gas was introduced at 200 sccm and oxygen gas at 1500 sccm. The pressure inside the vacuum chamber was adjusted to 8 Pa by adjusting the exhaust rate, and plasma treatment was performed at a power of 370 W. The PCTFE film was transported at speeds of 0.05 m / min, 0.15 m / min, and 0.45 m / min, performing plasma treatment under different conditions. After plasma treatment was completed, the discharge and gas supply were stopped, the pressure was reduced to 0.01 Pa or less, and the chamber was vented to return to atmospheric pressure, yielding a plasma-treated PCTFE film.

[0116] In addition, the surface of the PP film was irradiated with electron beams using an electron beam irradiation device (line irradiation type low energy electron beam irradiation device EES-L-DP01, manufactured by Hamamatsu Photonics K.K.) at a voltage of 70 kV, an absorbed dose of 300 kGy, and an oxygen concentration in the device of 100 ppm or less, after purging with nitrogen gas so that the oxygen concentration in the chamber of the electron beam irradiation device was 100 ppm or less.

[0117] Next, the plasma-treated side of the PCTFE film and the electron beam-irradiated side of the PP film were stacked facing each other, and the films were heat-pressed together by a thermal lamination method at a heating temperature of 180°C for the PCTFE film and a heating temperature of 150°C for the PP film to obtain a laminate.

[0118] [Examples 1 and 2] (Preparation of laminate) First, the surface of the PCTFE film was subjected to plasma treatment using the roll-to-roll type plasma treatment device described above, introducing argon gas at a flow rate of 200 sccm and a pressure of 8 Pa, while varying the film conveying speed between 0.15 m / min and 0.45 m / min at an output of 370 W. Next, using an electron beam irradiation device (line irradiation type low-energy electron beam irradiation device EES-L-DP01, manufactured by Hamamatsu Photonics K.K.), the surface of the PCTFE film was irradiated with electron beams at a voltage of 70 kV, an absorbed dose of 300 kGy, and an oxygen concentration in the device of 100 ppm or less, after purging with nitrogen gas so that the oxygen concentration in the chamber of the electron beam irradiation device was 100 ppm or less. Next, after irradiation with the electron beam, the PCTFE film was left for one day.

[0119] In addition, the surface of the PP film was irradiated with electron beams using an electron beam irradiation device (line irradiation type low energy electron beam irradiation device EES-L-DP01, manufactured by Hamamatsu Photonics K.K.) at a voltage of 70 kV, an absorbed dose of 300 kGy, and an oxygen concentration in the device of 100 ppm or less, after purging with nitrogen gas so that the oxygen concentration in the chamber of the electron beam irradiation device was 100 ppm or less.

[0120] Next, the PCTFE film and the PP film were stacked with the electron beam irradiated surfaces facing each other, and were thermocompression bonded by a thermal lamination method at a heating temperature of 180°C for the PCTFE film and a heating temperature of 150°C for the PP film to obtain a laminate.

[0121] [Comparative Examples 4 and 5] Laminates were prepared in the same manner as in Examples 1 and 2, except that the PCTFE film was irradiated with electron beams and then immediately subjected to thermocompression bonding.

[0122] Comparative Example 6 (Preparation of laminate) The surfaces of the PCTFE film and the PP film were each irradiated with electron beams using an electron beam irradiation device (line irradiation type low energy electron beam irradiation device EES-L-DP01, manufactured by Hamamatsu Photonics K.K.) at a voltage of 70 kV, an absorbed dose of 300 kGy, and an oxygen concentration in the device of 100 ppm or less, after purging with nitrogen gas so that the oxygen concentration in the device was 100 ppm or less.

[0123] Next, the PCTFE film and the PP film were stacked so that the electron beam irradiated surfaces faced each other, and then heat-pressed by a thermal lamination method at a heating temperature of 180°C for the PCTFE film and a heating temperature of 150°C for the PP film to obtain a laminate.

[0124] [evaluation] (peel strength) Peel strength was measured according to JIS P8139. The resulting laminate was cut into a 15 mm wide strip and subjected to a 90-degree peel test using a surface property tester manufactured by Shinto Scientific Co., Ltd. (HEIDON Tribogear Surface Property Tester TYPE:14 T-type Peel Unit) at a temperature of 23°C ± 1°C and a pulling speed of 50 mm / min. The results are shown in Table 2.

[0125] [Table 2]

[0126] Table 2 shows that the peel strength increases when the PCTFE film is subjected to a plasma treatment. Furthermore, Example 1 and Comparative Example 2, and Example 2 and Comparative Example 3, which have the same plasma treatment intensity, show that the peel strength increases when the PCTFE film is subjected to both plasma treatment and electron beam irradiation. Furthermore, Examples 1 and 2 and Comparative Examples 4 and 5 show that the peel strength increases when the PCTFE film is left for a certain period of time after electron beam irradiation.

[0127] (Interface observation) The cross section of the obtained laminate was observed using a scanning transmission electron microscope (STEM). First, the entire laminate was embedded and fixed, and then stained. Ruthenium tetroxide was used as the staining agent. Next, sections were prepared to obtain the laminate cross section. An ultramicrotome EM UC7 manufactured by Leica Microsystems was used to prepare the sections. The cross section of the laminate was then observed using a scanning transmission electron microscope (STEM). The scanning transmission electron microscope (STEM) used was an SU8000 or SU9000 manufactured by Hitachi High-Technologies Corporation. The observation conditions were as follows: observation mode: TE, acceleration voltage: 30 kV, emission current: 10 μA. STEM images are shown in Figures 5(a) to 5(e).

[0128] In all of Comparative Examples 1 to 3 and Examples 1 and 2, the interface between the PCTFE film and the PP film had an uneven shape.

[0129] (Thickness of joint and height of uneven shape) The cross section of the obtained laminate was observed by STEM, and the maximum thickness (maximum height Rz) of the joint and the average height (average height Rc) of the uneven shape were determined by a method conforming to JIS B0601: 2013. The laminate of Example 1 had a maximum thickness (maximum height Rz) of the joint of 0.66 μm and an average height (average height Rc) of the uneven shape of 0.55 μm.

[0130] (IR spectrum) A cross section of the obtained laminate was subjected to AFM-IR (AFM-based Infrared Spectroscopy) measurement using a nanoIR manufactured by Anasys Instruments, Inc. The measurement conditions were as follows. ·Light source: Tunable Pulsed Laser (1kHz) AFM mode: Contact mode (when acquiring AFM-IR spectrum) Measurement wavenumber range: 1800~1000cm -1 ·Wave number resolution: 1.5cm -1 Coverages:512 Number of times accumulated: 3 or more Polarization angle: 45 degrees

[0131] The IR spectrum was measured at three locations in each measurement region and averaged. The optical microscope image, AFM image, and IR spectrum of the cross section of the laminate of Example 1 are shown in Figure 6. The optical microscope image, AFM image, and IR spectrum of the cross section of the laminate of Comparative Example 1 are shown in Figure 7.

[0132] In the laminate of Example 1, the IR spectrum of the interface between the PCTFE film and the PP film shows a peak at 1150 cm -1 In the IR spectrum of the interface, a peak appeared at 1465 cm that was not attributable to either PCTFE or PP. -1 The peak intensity of 1376 cm originating from the CH3 bending angle of PP -1 In the IR spectrum of the interface, the peak intensity at 1465 cm , which is due to the CH bending angle of PP, decreased. -1 The peak intensity of 1735 cm due to C=O stretching -1 The intensity of the peak at 1150 cm -1 The peak is thought to be due to COC stretching.

[0133] In the laminate of Example 2, as in Example 1, the IR spectrum of the interface between the PCTFE film and the PP film showed a peak at 1150 cm -1 A peak not attributable to either PCTFE or PP appeared.

[0134] On the other hand, in the laminate of Comparative Example 1, in the IR spectrum of the interface between the PCTFE film and the PP film, -1 In addition, in the IR spectrum of the interface, the peak at 1465 cm resulting from the CH bending angle of PP did not appear. -1 The peak intensity of 1376 cm originating from the CH3 bending angle of PP -1 The peak intensity at 1465 cm , which is derived from the CH bending of PP, was also slightly reduced. -1The peak intensity of 1725 cm due to C=O stretching -1 The peak intensity increased.

[0135] In the laminates of Comparative Examples 2 and 3, similarly to Comparative Example 1, the IR spectrum of the interface between the PCTFE film and the PP film showed a peak at 1150 cm -1 The peak did not appear.

[0136] In the IR spectrum of the cross section of the laminate of Comparative Example 1, a 1725 cm bond due to C═O stretching was observed. -1 Taking this into consideration along with the results of the XPS measurements described above, the peak is thought to be due to oxygen being introduced into the surface of the PCTFE film by the argon plasma treatment.

[0137] Furthermore, AFM-IR measurements were performed on the cross sections of the laminates of Example 1 and Comparative Example 1 using a nanoIR manufactured by Anasys Instruments, and line analysis was performed. The AFM image and IR spectrum of the cross section of the laminate of Example 1 are shown in FIG. 8 . The AFM image and IR spectrum of the cross section of the laminate of Comparative Example 1 are shown in FIG. 9 . The peak intensities or intensity ratios were also profiled from the line spectra. The results are shown in FIG. 10 .

[0138] 10, comparing the change in the peak intensity resulting from the CH bending angle of PP with the change in the peak intensity resulting from the CF2 stretching of PCTFE for the laminates of Example 1 and Comparative Example 1, it was found that in both Example 1 and Comparative Example 1, PP had diffused toward the PCTFE film side, and PCTFE had diffused toward the PP film side, that is, a joint where PCTFE and PP were mixed was formed at the interface between the PCTFE film and the PP film. Furthermore, it appears that the degree of PCTFE diffusion toward the PP film side is large in both Example 1 and Comparative Example 1.

[0139] Furthermore, the change in the ratio of the peak intensity due to C=O stretching to the peak intensity due to C-H bending of PP indicated that the C=O group was localized at the interface between the PCTFE film and the PP film. This is thought to be due to the introduction of oxygen to the surface of the PCTFE film by the argon plasma treatment, as mentioned above.

[0140] 8 to 10, in Example 1 and Comparative Example 1, the -1 The peak at 1150 cm was observed only in the laminate of Example 1. -1 The peak is thought to be due to C-O-C stretching, and it is thought that a C-O-C bond was formed between PCTFE and PP.

[0141] From the above, it can be inferred that in Examples 1 and 2, covalent bonds are formed between atoms in the PCTFE film and atoms in the PP film at the interface between the PCTFE film and the PP film.

[0142] (Fluorine content of PCTFE film) The fluorine content in the thickness direction of the PCTFE film of the resulting laminate was measured using STEM-EDX under the following measurement conditions. Acceleration voltage: 30.0 kV Emission current: 10μA Probe current: High Magnification: 20,000x or 30,000x WD:8mm Tilt: 0° Detector element area: 100mm 2 Windowless

[0143] Figures 11(a) and (b) show the results of STEM-EDX analysis of the laminate of Example 1. The solid lines in the STEM image shown in Figure 11(a) indicate the measurement points. Figures 11(a) and (b) confirm that the amount of fluorine contained in the PCTFE film decreases in the thickness direction, from the inside of the PCTFE film toward the joint side.

[0144] [Example 3] (Preparation of laminate) A polyvinyl chloride resin (PVC) film (C-0471, manufactured by Mitsubishi Chemical Corporation, thickness 200 μm) was prepared as a resin member containing a polyvinyl chloride resin. A polyolefin resin-containing resin member was prepared by forming a polypropylene resin (PP) film (Zelas 7025, manufactured by Mitsubishi Chemical Corporation) into a film with a thickness of 70 μm by an inflation method.

[0145] First, the surface of the PVC film was subjected to plasma treatment using the roll-to-roll type plasma treatment device described above, with argon gas introduced at a flow rate of 200 sccm and a pressure of 8 Pa, at an output of 370 W and a film conveying speed of 0.05 m / min. Next, the surface of the PVC film was irradiated with electron beams using an electron beam irradiation device (line irradiation type low-energy electron beam irradiation device EES-L-DP01, manufactured by Hamamatsu Photonics K.K.) at a voltage of 70 kV, an absorbed dose of 300 kGy, and an oxygen concentration in the device of 100 ppm or less, after purging with nitrogen gas so that the oxygen concentration in the chamber of the electron beam irradiation device was 100 ppm or less. After irradiation with the electron beam, the PVC film was left for one day.

[0146] In addition, the surface of the PP film was irradiated with electron beams using an electron beam irradiation device (line irradiation type low energy electron beam irradiation device EES-L-DP01, manufactured by Hamamatsu Photonics K.K.) at a voltage of 70 kV, an absorbed dose of 300 kGy, and an oxygen concentration in the device of 100 ppm or less, after purging with nitrogen gas so that the oxygen concentration in the chamber of the electron beam irradiation device was 100 ppm or less.

[0147] Next, the PVC film and the PP film were stacked with the electron beam irradiated surfaces facing each other, and were thermocompression bonded by a thermal lamination method at a heating temperature of 150°C for the PVC film and a heating temperature of 150°C for the PP film to obtain a laminate.

[0148] (peel strength) The peel strength was measured in the same manner as in Examples 1 and 2 and was found to be 3.0 N / 15 mm.

[0149] Comparative Example 7 (Preparation of laminate) A laminate was produced in the same manner as in Example 3, except that only the PVC film was irradiated with electron beams.

[0150] (peel strength) The peel strength was measured in the same manner as in Examples 1 and 2 and was found to be 2.5 N / 15 mm.

[0151] From Example 3 and Comparative Example 7, it was found that the peel strength increased when the PVC film was subjected to plasma treatment and electron beam irradiation, and when the PP film was subjected to electron beam irradiation. [Explanation of symbols]

[0152] 1 ... Laminate 2 ... First resin member 3... Second resin member 4…Joint part

Claims

1. A laminate in which a first resin member and a second resin member containing different resins are joined together, a joint portion at an interface between the first resin member and the second resin member, in which the resin contained in the first resin member and the resin contained in the second resin member are mixed; the bonded portion has a peak attributable to a chemical bond that can be formed between the resin contained in the first resin member and the resin contained in the second resin member in a spectrum measured by infrared spectroscopy, The maximum thickness of the joint is 100 nm or more and 10 μm or less, In the joint portion, an interface between the first resin member and the second resin member has an uneven shape, the first resin member contains a fluorine-based resin, and the second resin member contains a resin that is substantially free of fluorine; A laminate, wherein the amount of fluorine contained in the first resin member decreases in a thickness direction of the first resin member from the inside of the first resin member toward the surface of the first resin member on the joining portion side.

2. The laminate according to claim 1 , wherein the second resin member contains a polyolefin resin.

3. The laminate according to claim 1 or 2, wherein the joint portion has a covalent bond between an atom contained in the first resin member and an atom contained in the second resin member.

4. A method for manufacturing a laminate that joins a first resin member and a second resin member that contain different resins, the method comprising: a first step of subjecting one surface of the first resin member to plasma treatment, irradiating the surface with an electron beam, and then leaving the surface for six hours or more; a second step of irradiating one surface of the second resin member with an electron beam; a third step of placing the surface of the first resin member that has been subjected to the plasma treatment and irradiated with the electron beam opposite a surface of the second resin member that has been irradiated with the electron beam, and thermocompression bonding the first resin member and the second resin member together; and In the first step, the plasma treatment is performed on the one surface of the first resin member to form an uneven shape on the one surface of the first resin member; A method for producing a laminate, wherein the first resin member contains a fluorine-based resin, and the second resin member contains a resin that does not substantially contain fluorine.

5. The method for producing a laminate according to claim 4 , wherein the second resin member contains a polyolefin resin.

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