Bonded body and method for manufacturing same

Abstract

The objective of the present invention is to provide a bonded body which has excellent flexural modulus and bonding strength and in which a decrease in transparency due to an increase in haze during the generation of water vapor is suppressed. A bonded body according to the present invention includes a plurality of molded bodies made of a thermoplastic resin and a bonding layer that bonds the molded bodies together, wherein the bonding layer comprises at least one cyclic olefin polymer, and a solvent component with a predetermined boiling point range, and contains the solvent component with a predetermined boiling point range within a predetermined trace concentration range.

Description

Joint and manufacturing method thereof

[0001] The present invention relates to a bonded body and a method for producing the same.

[0002] As a microchannel chip used for the analysis, testing, etc. of biological materials such as DNA, RNA, and proteins, as well as chemical substances, it is described that a resin conjugate is produced by interposing a bonding layer between a resin substrate having a fine channel formed therein and a cover substrate, and bonding them by heating (see, for example, Patent Documents 1 and 2).

[0003] Furthermore, when producing a resin laminate such as a laminate film or a pressure-sensitive adhesive tape, a method is described in which a resin dissolved in a solvent is applied to the surface of a resin substrate, and the solvent is then dried and removed to form a laminated resin layer (e.g., Patent Documents 3 and 4).

[0004] International Publication No. 2021 / 241516 Patent No. 4752364 JP 2007-276142 A JP 2003-306650 A

[0005] The technology for producing a resin bonded body, in which multiple resin molded bodies are bonded via a bonding layer, is expected to be highly applicable not only to microchannel chips but also to the production of multiwell plates and other resin parts or components in general. Such resin bonded bodies are required to have excellent mechanical properties, such as flexural modulus and bonding strength. Furthermore, when the bonded body is used after autoclave sterilization, water vapor generated in the autoclave can remain in the resin, increasing haze and reducing the transparency of the bonded body. Therefore, it is necessary to suppress the loss of transparency due to increased haze.

[0006] Therefore, an object of the present invention is to provide a bonded body that is excellent in flexural modulus and bonding strength and that is inhibited from losing transparency due to an increase in haze under water vapor generation, and a method for producing the same.

[0007] The present invention aims to advantageously solve the above-mentioned problems. The present invention provides a bonded structure comprising a plurality of molded articles made of a thermoplastic resin and a bonding layer bonding the molded articles together. The bonding layer comprises at least one type of cyclic olefin polymer and a solvent component having a boiling point of 70°C to 150°C. The bonded structure contains the solvent component having a boiling point of 70°C to 150°C in an amount of 100 ppm by mass to 800 ppm by mass, based on the total mass of the bonded structure. By including at least one type of cyclic olefin polymer in the bonding layer and having a solvent component content within a predetermined range in the bonded structure, a bonded structure can be provided that exhibits excellent bonding strength and flexural modulus, and exhibits excellent transparency after autoclave sterilization. The solvent component content can be measured, for example, by the method described in the Examples.

[0008] In the bonded structure of the present invention, the thickness of the bonding layer is preferably 0.1 μm or more and 5 μm or less. If the thickness of the bonding layer does not exceed the above upper limit, the thickness of the bonding layer becomes thinner, resulting in a thin film, which reduces the chance of haze generation in the bonding layer and improves the transparency of the bonded structure. Furthermore, when the bonded structure is used as a device for biological or chemical analysis, such as a microchannel chip or a multiwell plate, deformation of the channels of the microchannel chip or the wells of the multiwell plate during steam sterilization is suppressed. Conversely, if the thickness of the bonding layer does not fall below the above lower limit, the bonding strength effect of the bonding layer is exerted. The thickness of the bonding layer can be measured, for example, by the method described in the Examples.

[0009] In the bonded structure of the present invention, the thermoplastic resin is preferably a resin containing a cyclic olefin polymer. By using a cyclic olefin polymer resin as the thermoplastic resin, the bonded structure can be provided with excellent properties such as heat resistance and dimensional stability. Furthermore, since the cyclic olefin polymer resin is of the same polymer category as the cyclic olefin polymer that is the material of the bonding layer, they can be easily fused to each other, thereby providing the bonded structure with even better bonding strength.

[0010] In the bonded structure of the present invention, the solvent component preferably contains at least one of cyclohexane, methylcyclohexane, ethylcyclohexane, xylene, and toluene. These solvent components have high solubility for cyclic olefin polymers, making it possible to obtain a bonding layer with excellent uniformity. The type of solvent component can be identified, for example, by the method described in the Examples.

[0011] The method for producing a bonded body of the present invention includes the steps of: applying a bonding agent containing at least one cyclic olefin and a solvent-soluble component having a boiling point of 70°C to 150°C to at least one surface of a first molded body made of a thermoplastic resin; drying the applied bonding agent to remove most of the solvent-soluble component from the bonding agent and form a bonding layer on the first molded body surface; and placing a second molded body made of a thermoplastic resin so that it is in contact with the bonding layer and subjecting the second molded body to a heating and pressurizing treatment to bond the first molded body and the second molded body via the bonding layer to obtain a bonded body containing the solvent-soluble component in an amount of 100 ppm by mass to 800 ppm by mass relative to the total mass of the bonded body. By forming the bonding layer using a bonding agent containing at least one cyclic olefin and a solvent-soluble component having a boiling point of 70°C to 150°C and controlling the content of the solvent-soluble component in the bonded body to a predetermined range, a bonded body can be produced that has excellent bonding strength and flexural modulus and excellent transparency after autoclave sterilization.

[0012] According to the present invention, it is possible to provide a bonded body that is excellent in flexural modulus and bonding strength and that is inhibited from losing transparency due to an increase in haze under the generation of water vapor, and a method for producing the same.

[0013] Fig. 1a shows a full-surface bonded assembly 30 used for measuring bending modulus, with a side view on the top and a top view on the bottom. Fig. 1b shows a schematic diagram of bending modulus measurement. Fig. 2a shows a bonded assembly 20 used for measuring bonding strength, with a side view on the top and a top view on the bottom. Fig. 2b shows a schematic diagram of bonding strength measurement.

[0014] Hereinafter, embodiments of the present invention will be described in detail.

[0015] (Jointed Structure) The joined structure of the present invention includes a plurality of molded bodies made of a thermoplastic resin and a bonding layer bonding the molded bodies together. The bonding layer includes at least one type of cyclic olefin and a solvent component having a boiling point within a predetermined range, and the joined structure includes the solvent component having a boiling point within a predetermined trace concentration range. The predetermined boiling point range must be 70°C or higher and 150°C or lower. The predetermined trace concentration range must be 100 mass ppm or higher and 800 mass ppm or lower with respect to the total mass of the joined structure. By including at least one type of cyclic olefin polymer in the bonding layer and by having the solvent component content within the predetermined range in the joined structure, a joined structure can be provided that exhibits excellent bonding strength and flexural modulus, and exhibits excellent transparency after autoclave sterilization.

[0016] <Conjugated Structure> The term "conjugated structure" refers to a general product, part, or member (especially a resin-made one) formed by bonding multiple molded bodies together via a bonding layer. Examples of the conjugated structure include, but are not limited to, devices (e.g., microchannel chips, multiwell plates, etc.) used for the analysis, testing, reaction, etc. of biological materials (e.g., DNA, RNA, proteins, etc.) and chemical substances (low molecular weight compounds, high molecular weight compounds, etc.), or for the analysis, testing, or culturing of living organisms or living organism-like objects (bacteria, cultured cells, viruses, etc.), as well as resin products, parts, and members (e.g., resin caster wheels, resin screws, resin housings, resin gaskets, etc.). The conjugated structure is preferably a device for analysis, testing, etc., such as a microchannel chip or multiwell plate, which requires good transparency.

[0017] <Molded Product> A "molded product" refers to a plurality of resin members to be bonded together to form a bonded product. The shape of the molded product may be determined depending on the type, function, and shape of the bonded product. For example, when the bonded product is a microchannel chip, the molded product may be a combination of a channel-equipped substrate and a cover substrate. When the bonded product is a multiwell plate, the molded product may be a combination of a well-equipped substrate and a cover substrate. In either case, the cover substrate may be a flat plate or a flat plate with holes.

[0018] The molded article can be formed, for example, by injection molding of a resin. The formation of a recessed or opening structure formed on the bonding surface, such as a channel, well, or through-hole that can be formed on a substrate, can be carried out using, for example, microfabrication techniques such as photolithography and thermal imprinting, cutting, injection molding, or the like. The formation of the recessed or opening structure may be carried out on a molded article on which no bonding layer has been formed, or on a molded article on which a bonding layer has been formed. The formation of a recessed or opening structure on a molded article on which no bonding layer has been formed can be carried out using, for example, microfabrication techniques such as photolithography and thermal imprinting, cutting, injection molding, or the like. The formation of a recessed or opening structure on a molded article on which a bonding layer has been formed can be carried out by applying, for example, microfabrication techniques such as photolithography and thermal imprinting, cutting, or the like, to the surface of the molded article on which the bonding layer has been formed.

[0019] <<Material of Molded Body: Thermoplastic Resin>> The molded body is made of a thermoplastic resin. The molded bodies may be made of the same thermoplastic resin or different thermoplastic resins. By using a thermoplastic resin as the molded body material, when the molded bodies are bonded together via a bonding layer by heat and pressure treatment, the bonding interface of the molded bodies becomes more compatible with heat, thereby imparting excellent bonding strength to the bonded body. Examples of thermoplastic resins include, but are not limited to, resins containing cyclic olefin polymers, polystyrene, polycarbonate, acrylic polymers, polyethylene terephthalate, etc. Examples of cyclic olefin polymers include those described below. Acrylic polymers are polymers containing repeating units (polymerization units) obtained by polymerizing acrylate or methacrylate (hereinafter sometimes abbreviated as "(meth)acrylate") and their derivatives. Specific examples include (meth)acrylate homopolymers, (meth)acrylate copolymers, and copolymers of (meth)acrylate and other monomers copolymerizable with the (meth)acrylate. Examples of the (meth)acrylate include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, and 2-ethylhexyl acrylate; alkoxyalkyl acrylates such as 2-methoxyethyl acrylate and 2-ethoxyethyl acrylate; 2-(perfluoroalkyl)ethyl acrylates such as 2-(perfluorobutyl)ethyl acrylate and 2-(perfluoropentyl)ethyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, and stearyl methacrylate; and 2-(perfluoroalkyl)ethyl methacrylates such as 2-(perfluorobutyl)ethyl methacrylate and 2-(perfluoropentyl)ethyl methacrylate.

[0020] If a cyclic olefin polymer is used as the thermoplastic resin, it will be of the same polymer category as the cyclic olefin polymer used as the material for the bonding layer, and therefore they will be more easily fused to each other, thereby imparting even greater bonding strength to the bonded body. Furthermore, cyclic olefin polymers are resins with excellent heat resistance, dimensional stability, acid resistance, alkali resistance, hydrolysis resistance, light weight, and ease of resin molding, and therefore can impart excellent properties to the bonded body. In particular, cyclic olefin polymers are suitable as a molded body material that imparts excellent durability to the bonded body because they exhibit little deterioration in bonding strength or dimensional change over time due to moisture absorption. Furthermore, cyclic olefin polymers are transparent and have low autofluorescence, making them suitable for use in optical signal detection devices such as microchannel chips and multiwell plates. Furthermore, molded bodies whose bonding surfaces have been corona discharge-treated may be used to enhance bonding strength. The glass transition temperature (Tg1) of the molded body will be described later.

[0021] <<Thickness of Molded Article>> The thickness of the molded article (the thickness in the stacking direction when the bonded body is viewed as a laminate of the molded article and the bonding layer) is not particularly limited, and may be, for example, 0.5 mm or more, preferably 1 mm or more, and more preferably 1.5 mm or more, and may be, for example, 100 mm or less, preferably 50 mm or less, and more preferably 20 mm or less.

[0022] <Bonding Layer> A "bonding layer" is a layer-type member interposed between molded bodies to bond the molded bodies together. The bonding layer is characterized by containing at least one type of cyclic olefin polymer and a solvent component having a boiling point within a predetermined range, such that the content ratio of the solvent component in the bonded body falls within a predetermined trace concentration range. The predetermined boiling point range must be 70°C or higher and 150°C or lower. The predetermined trace concentration range must be 100 mass ppm or higher and 800 mass ppm or lower with respect to the total mass of the bonded body. By containing at least one type of cyclic olefin polymer and a solvent component having a boiling point within a predetermined range, such that the content ratio of the solvent component in the bonded body falls within the predetermined trace concentration range, a bonded body can be provided that has excellent bonding strength and flexural modulus, and that has excellent transparency after autoclave sterilization.

[0023] <<Main Material of Bonding Layer: Cyclic Olefin Polymer>> The bonding layer contains at least one cyclic olefin polymer as its main material (for example, at a content of 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the entire bonding layer). When a cyclic olefin polymer is used as the main material of the bonding layer, particularly when the molded body is made of a cyclic olefin polymer, the bonding layer and the molded body are easily fused to each other because they are both resins of the same category, i.e., cyclic olefin polymers. This increases the adhesion between the bonding layer and the molded body, thereby imparting excellent bonding strength to the bonded body. Furthermore, cyclic olefin polymers are resins that have excellent heat resistance, dimensional stability, acid resistance, alkali resistance, hydrolysis resistance, light weight, and ease of resin molding, and therefore can impart excellent properties to the bonded body. In particular, cyclic olefin polymers are suitable as bonding layer materials that impart excellent durability to the bonded body because they exhibit little decrease in bonding strength or dimensional change over time due to moisture absorption. Furthermore, since the cyclic olefin polymer is a transparent material with low autofluorescence, it is suitable for use in optical signal detection devices such as microchannel chips and multiwell plates. ２ ) will be discussed later.

[0024] <<Other Properties of Cyclic Olefin Polymer for Bonding Layer>> As other properties of the cyclic olefin polymer used as the main material of the bonding layer, for example, it is preferable that the water absorption rate is 0.01 mass% or less, from the viewpoint of suppressing the generation of haze due to water vapor absorption and the decrease in durability due to moisture absorption.

[0025] <<Thickness of the Bonding Layer>> The thickness of the bonding layer may be the minimum thickness necessary to ensure adhesion between the bonding surfaces of the molded articles interposed therebetween. For example, it may be 0.1 μm or more, preferably 0.12 μm or more, more preferably 0.15 μm or more, and even more preferably 0.2 μm or more. The thickness of the bonding layer may be, for example, 5 μm or less, preferably 4.5 μm or less, more preferably 4.2 μm or less, and even more preferably 4 μm or less. It is preferable that the thickness of the bonding layer does not exceed the above upper limit. The thinner the bonding layer, the thinner the bonding layer becomes, thereby reducing the chance of haze generation in the bonding layer and improving the transparency of the bonded body. Furthermore, for example, when the bonded body is used as a device for biological or chemical analysis, such as a microchannel chip or a multiwell plate, deformation of the channels of the microchannel chip or the wells of the multiwell plate during steam sterilization is suppressed. Conversely, if the thickness of the bonding layer is thinner than the above lower limit, the effect of the bonding layer on the bonding strength is reduced. When the bonded structure includes multiple bonding layers, at least one of the bonding layers may be within the above range, and it is preferable that all of the bonding layers be within the above range. The thickness of the bonding layer can be controlled by adjusting the cyclic olefin content in the bonding agent containing the cyclic olefin and the solvent component used to form the bonding layer, the amount of the bonding agent applied and other application conditions, and the drying conditions (e.g., temperature, time, etc.) for removing the solvent component when forming the bonding layer. The thickness of the bonding layer can be measured, for example, by the method described in the Examples.

[0026] <Cyclic Olefin Polymer> The cyclic olefin polymer that can be used as a material for the molded body and the cyclic olefin polymer that is the main material for the bonding layer are, for example, polymers or copolymers (hereinafter sometimes collectively referred to as "polymers") obtained by polymerizing monomers as described below, or hydrogenated products thereof. The cyclic olefin polymer may be crystalline or amorphous, but is preferably amorphous. Preferred examples of the monomer for the cyclic olefin polymer include norbornene-based monomers. Norbornene-based monomers are monomers containing a norbornene ring. Examples of norbornene-based monomers include bicyclic monomers such as bicyclo[2.2.1]hept-2-ene (common name: norbornene), 5-ethylidene-bicyclo[2.2.1]hept-2-ene (common name: ethylidenenorbornene), and derivatives thereof (those having a substituent on the ring); tricyclo[5.2.1.0]hept-2-ene (common name: ethylidenenorbornene), and derivatives thereof (those having a substituent on the ring); ２，６ ]deca-3,8-diene (common name: dicyclopentadiene) and tricyclic monomers such as its derivatives; tetracyclo[7.4.0.0 ２，７ .1 １０，１３ ]tetradeca-2,4,6,11-tetraene (common name: methanotetrahydrofluorene), tetracyclo[6.2.1.1 ３，６ .0 ２，７ ] dodec-4-ene (common name: tetracyclododecene), 9-ethylidenetetracyclo[6.2.1.1 ３，６ .0 ２，７ ]dodec-4-ene and tetracyclic monomers such as derivatives thereof; etc. These monomers may have a substituent at any position. Examples of the substituent include an alkyl group, an alkylene group, a vinyl group, an alkoxycarbonyl group, and an alkylidene group, and the norbornene-based monomers may have two or more of these. Specific examples of the derivatives include 8-methoxycarbonyl-tetracyclo[4.4.0.1 ２，５ .1 ７，１０ ] dodec-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo[4.4.0.1 ２，５ .1 ７，１０ ] dodec-3-ene, 8-ethylidene-tetracyclo[4.4.0.1 ２，５ .1 ７，１０]dodec-3-ene, etc. These norbornene-based monomers may be used alone or in combination of two or more. The cyclic olefin polymer may be an addition polymer, a ring-opening polymer, or a hydrogenated product thereof, but is preferably a ring-opening polymer or a hydrogenated ring-opening polymer.

[0027] The ring-opening polymers described above can be produced by a method using a ring-opening polymerization catalyst. Examples of the ring-opening polymerization catalyst include a catalyst composed of a halide of a metal such as ruthenium or osmium, a nitrate or an acetylacetone compound, and a reducing agent, or a catalyst composed of a halide or an acetylacetone compound of a metal such as titanium, zirconium, tungsten, or molybdenum, and an organoaluminum compound. Ring-opening polymers can be produced, for example, by a method using a metathesis reaction catalyst (ring-opening polymerization catalyst) such as the ruthenium carbene complex catalyst described in International Publication No. 2010 / 110323, or a method using a ring-opening polymerization catalyst such as a tungsten(phenylimide)tetrachloride-tetrahydrofuran complex or tungsten hexachloride described in Japanese Patent Application Laid-Open No. 2015-54885. The addition polymers described above can be obtained by polymerizing a monomer using a known addition polymerization catalyst, for example, a catalyst composed of a titanium, zirconium, or vanadium compound and an organoaluminum compound. The addition polymer can be produced, for example, by addition copolymerizing a cyclic olefin polymer monomer and, if necessary, an addition-copolymerizable monomer (another monomer) in the presence of a metallocene catalyst described in WO 2017 / 199980.

[0028] Examples of other monomers that can be ring-opening copolymerized with norbornene-based monomers include monocyclic olefin-based monomers such as cyclohexene, cycloheptene, and cyclooctene. These other monomers that can be ring-opening copolymerized with norbornene-based monomers can be used alone or in combination of two or more. When a norbornene-based monomer is ring-opening copolymerized with another monomer that can be ring-opening copolymerized with it, the weight ratio of the structural units derived from the norbornene-based monomer to the structural units derived from the other monomer that can be ring-opening copolymerized in the ring-opening polymer is appropriately selected so as to be typically within a range of 70:30 to 99:1, preferably 80:20 to 99:1, and more preferably 90:10 to 99:1.

[0029] Examples of other monomers that can be addition-copolymerized with norbornene-based monomers include α-olefins having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-pentene, and 1-hexene, and derivatives thereof; cycloolefins, such as cyclobutene, cyclopentene, cyclohexene, cyclooctene, and 3a,5,6,7a-tetrahydro-4,7-methano-1H-indene, and derivatives thereof; and non-conjugated dienes, such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and 1,7-octadiene. Among these, α-olefins are preferred, and ethylene is particularly preferred. These other monomers that can be addition-copolymerized with norbornene-based monomers can be used alone or in combination of two or more. When a norbornene-based monomer is addition-copolymerized with another monomer that is addition-copolymerizable therewith, the weight ratio of the structural units derived from the norbornene-based monomer to the structural units derived from the other monomer that is addition-copolymerizable therewith is appropriately selected so as to be usually in the range of 30:70 to 99:1, preferably 50:50 to 97:3, and more preferably 70:30 to 95:5.

[0030] Furthermore, examples of methods for producing a hydrogenated cyclic olefin polymer by hydrogenating a ring-opening polymer include methods using the hydrogenation catalysts described in WO 2010 / 110323. Alternatively, for example, a cyclic olefin polymer may be produced using the above-mentioned ruthenium carbene complex catalyst as a ring-opening polymerization catalyst, and then the ruthenium carbene catalyst may be used as a hydrogenation catalyst as is to hydrogenate the cyclic olefin polymer to produce a hydrogenated cyclic olefin polymer.

[0031] The weight average molecular weight (Mw) of the cyclic olefin polymer that can be used as a material for the molded body and the bonding layer is preferably 1,000 or more, more preferably 10,000 or more, even more preferably 20,000 or more, and preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 200,000 or less. The number average molecular weight (Mn) of the cyclic olefin polymer that can be used as a material for the molded body is preferably 1,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, and preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 100,000 or less. The weight average molecular weight (Mw) and number average molecular weight (Mn) of the cyclic olefin polymer can be measured by the method described in the Examples.

[0032] <Glass Transition Temperature of Molded Article and Joined Article> The glass transition temperature (Tg １ , the glass transition temperature of the resin component constituting the molded body) and the glass transition temperature (Tg ２ , the glass transition temperature of the resin component constituting the bonding layer) preferably satisfies the following: １ >Tg ２ By satisfying the above relationship, in the production of a bonded body, bonding of the molded bodies to each other can be performed at a temperature of Tg ２ Higher and Tg １ If the bonding is carried out at a lower temperature, only the bonding layer can be softened without softening, deforming or altering the molded body, and bonding by heat fusion becomes possible.

[0033] Tg １ is preferably 125°C or higher, more preferably 130°C or higher. １When the Tg is in this range, the molded article can be prevented from softening, deformation, or deterioration due to heating during the production of the bonded body and optional sterilization (e.g., autoclaving). １ is preferably 180° C. or less, more preferably 160° C. or less. １ and Tg ２ The difference is 10°C or more (i.e., Tg １ ≧Tg ２ +10°C), and preferably 15°C or higher (i.e., Tg １ ≧Tg ２ +15°C), more preferably 20°C or higher (i.e., Tg １ ≧Tg ２ +20°C) is more preferred. １ and Tg ２ The larger the difference between Tg １ and Tg ２ The difference between Tg is preferably 100°C or less, more preferably 90°C or less, and even more preferably 80°C or less. １ and Tg ２ The smaller the difference, the better the temperature stability of the bonding layer.

[0034] Tg ２ is preferably 50°C or higher, more preferably 65°C or higher. ２ When Tg is in this range, the temperature stability of the bonding layer is good. ２ is preferably 130°C or less, more preferably 110°C or less, and even more preferably 100°C or less. ２ When the temperature is in this range, it becomes easy to set the heating temperature for softening only the bonding layer in the production of the bonded body.

[0035] In the present invention, the glass transition temperature can be measured by differential scanning calorimetry (DSC) based on JIS-K7121.

[0036] The glass transition temperature (Tg) of the thermoplastic resin and the cyclic olefin polymer can be appropriately adjusted depending on the type and blending ratio of the monomer used in the polymerization, the average molecular weight and molecular weight distribution of the polymer, and, in the case of a polymer mixture, the glass transition temperature (Tg) and blending ratio of each polymer.

[0037] In the bonded body of the present invention, at least one of the bonded body and the bonding layer may be composed of two or more layers having different Tg's.

[0038] <Solvent-Based Component> The bonded body contains a solvent-based component with a boiling point within a predetermined range as a minor component. The bonding layer of the bonded body is typically formed by applying a bonding agent, in which a cyclic olefin polymer, the main material of the bonding layer, is dissolved in a solvent, to the surface of a molded body during production of the bonded body, and then drying the applied bonding agent to remove most of the solvent from the bonding agent. The "solvent-based component" refers to the solvent remaining as a minor component in the bonding layer or the like after most of the solvent has been removed from the bonding agent. The "solvent-based component" is a substance used as a solvent for the cyclic olefin polymer, the main material of the bonding layer, and is not particularly limited as long as it has a boiling point within a predetermined range. The solvent serving as the "solvent-based component" may be a single solvent or a mixed solvent. In the case of a mixed solvent, the "boiling point" refers to the boiling point of the mixed solvent. The boiling point of the mixed solvent can be adjusted based on the boiling points and blending ratios of each solvent component. Examples of solvents used as a single solvent or a component of a mixed solvent include commonly used organic solvents, such as toluene (boiling point 111°C), xylene (boiling point 144°C), tetrahydrofuran (THF) (boiling point 66°C), cyclohexane (boiling point 80.3°C), methylcyclohexane (boiling point 100.9°C), and ethylcyclohexane (boiling point 132°C). Furthermore, among these, solvents with boiling points within a predetermined range can be used as a single solvent. A boiling point within a predetermined range refers to a range of 70°C to 150°C. To ensure solubility as a solvent, a boiling point above the lower limit is usually required. Furthermore, to facilitate solvent removal by evaporation during the production of a bonded body, a boiling point below the upper limit is usually required. The solvent serving as a "solvent component" preferably includes at least one of cyclohexane, methylcyclohexane, ethylcyclohexane, xylene, and toluene.

[0039] When the bonded structure contains a solvent-based component as a trace component, the bonding layer also contains the solvent-based component as a trace component, which is thought to impart a certain level of fluidity to the bonding layer. Therefore, compared to when the entire bonded structure, including the bonding layer, is composed solely of resin components, the bonding layer is imparted with superior flexibility, and the bonded structure maintains its integrity with the molded body even when bent. Furthermore, compared to when the bonding layer is composed solely of resin components, the bonding layer is imparted with superior elasticity. The maintenance of integrity with the molded body and the excellent elasticity of the bonding layer itself can impart an excellent flexural modulus to the entire bonded structure. Furthermore, the bonding layer having a certain level of fluidity imparts superior adhesiveness to the bonding layer compared to when the bonding layer is composed solely of resin components, thereby imparting superior bonding strength between the molded bodies in the bonded structure. Furthermore, when the bonded structure is autoclave sterilized for use, water vapor generated during the autoclave sterilization process is easily absorbed into the resin. The absorbed water vapor remains trapped and condenses within the resin without diffusing, increasing haze and reducing the transparency of the bonded structure. On the other hand, if a certain degree of fluidity is imparted to the bonding layer as described above, even if water vapor is taken into the resin, the fluidity of the resin suppresses condensation, making it easier for the water vapor to escape to the outside, reducing haze and imparting excellent transparency to the bonded body.

[0040] <<Content of Solvent Component>> The bonded structure contains the solvent component in a predetermined trace concentration range. The predetermined trace concentration range is a content ratio of the solvent component relative to the total mass of the bonded structure of 100 ppm by mass or more, preferably 1050 ppm by mass or more, and more preferably 110 ppm by mass or more. Furthermore, the predetermined trace concentration range is a content ratio of the solvent component relative to the total mass of the bonding layer of 800 ppm by mass or less, preferably 750 ppm by mass or less, and more preferably 700 ppm by mass or less.

[0041] If the content ratio of the solvent component to the total mass of the bonded body is below the above lower limit, the content ratio of the solvent component to the total mass of the bonding layer also becomes extremely low, making the bonding layer hard and brittle, causing peeling during bending measurement and a decrease in the flexural modulus.Furthermore, the loss of fluidity of the bonding layer makes it easier for water vapor captured in the resin during autoclave sterilization to remain without escaping to the outside, increasing haze and impairing the transparency of the bonded body.On the other hand, if the content ratio of the solvent component to the total mass of the bonded body exceeds the above upper limit, the content ratio of the solvent component to the total mass of the bonding layer also becomes excessive, causing the bonding layer to become excessively soft, and the flexural modulus of the entire bonded body is likely to decrease.

[0042] From the above, by setting the content ratio of the solvent component relative to the total mass of the bonding layer within a predetermined trace concentration range, it is possible to provide a bonded body that is excellent in bonding strength and flexural modulus and that is excellent in transparency after autoclave sterilization. The content ratio of the solvent component can be measured, for example, by the method described in the Examples.

[0043] <Thickness of Bonded Body> The thickness of the bonded body (the thickness in the stacking direction when the bonded body is viewed as a laminate of the molded body and the bonding layer) is not particularly limited, and may be, for example, 1 mm or more, preferably 2 mm or more, and more preferably 3 mm or more, and may be, for example, 201 mm or less, preferably 101 mm or less, and more preferably 41 mm or less.

[0044] The bonded body of the present invention can be produced, for example, by the method for producing the bonded body of the present invention described below.

[0045] (Method for Manufacturing a Bonded Body) The method for manufacturing a bonded body of the present invention includes the following steps: (i) a step of applying a bonding agent containing at least one cyclic olefin and a solvent component having a boiling point within a predetermined range to at least one surface of a first molded body made of a thermoplastic resin (a bonding agent application step); (ii) a step of drying the applied bonding agent to remove most of the solvent component from the bonding agent and form a bonding layer on the surface of the first molded body (a bonding layer formation step); and (iii) a step of placing a second molded body made of a thermoplastic resin so as to be in contact with the bonding layer and performing a heating and pressurizing treatment to bond the first molded body and the second molded body via the bonding layer to obtain a bonded body containing the solvent component in a predetermined trace concentration range (a bonding step). The predetermined boiling point range must be 70°C or higher and 150°C or lower. The predetermined trace concentration range must be 100 ppm by mass or higher and 800 ppm by mass or lower with respect to the total mass of the bonded body. By forming a bonding layer using a bonding agent containing at least one type of cyclic olefin and a solvent component having a boiling point of 70°C or more and 150°C or less, and by adjusting the content of the solvent component in the bonded body to a predetermined trace concentration range, it is possible to produce a bonded body that has excellent bonding strength and flexural modulus, and that has excellent transparency after the bonded body is sterilized in an autoclave.

[0046] The bonded body obtained by the method for producing a bonded body of the present invention has a structure in which a first molded body and a second molded body are bonded via a bonding layer. When producing a bonded body in which three or more molded bodies are stacked, it is sufficient to form an additional bonding layer on at least one of the first molded body and the second molded body, and then stack and bond the additional molded body one or more times.

[0047] <Step (i): Bonding Agent Application Step> In step (i) (bonding agent application step), a bonding agent containing at least one type of cyclic olefin and a solvent component having a boiling point within a predetermined range is applied to at least one surface of a first molded body made of a thermoplastic resin. <<Bonding Agent>> The "bonding agent" refers to a coating liquid applied to the first molded body in step (i) to form a bonding layer. The bonding agent contains at least one type of cyclic olefin and a solvent component having a boiling point within a predetermined range. The cyclic olefin and solvent component of the bonding agent are the same as those used in the bonding layer. The content of the cyclic olefin in the bonding agent is not particularly limited, as long as the content of the solvent component in the bonded body obtained by this manufacturing method falls within the above-mentioned predetermined trace concentration range (i.e., 100 ppm by mass or more and 800 ppm by mass or less). Furthermore, among these content ratios, a content ratio that forms a bonding layer having a thickness within the preferred range described above in step (ii) (e.g., 0.1 μm or more and 5 μm or less) is preferred. The content ratio of the cyclic olefin in the bonding agent is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. In order to facilitate removal of solvent components by drying treatment, it is preferable that the content ratio of the cyclic olefin in the bonding agent is not too low. Furthermore, in order to impart sufficient solubility to the bonding agent and improve uniformity and ease of application, it is preferable that the content ratio of the cyclic olefin in the bonding agent is not too high.

[0048] <<Application of Bonding Agent>> The method for applying the bonding agent is not particularly limited, but examples thereof include bar coating, silk screening, spin coating, spray coating, wet coating, and gravure coating.

[0049] <Step (ii): Bonding layer forming step> In step (ii) (bonding layer forming step), the applied bonding agent is subjected to a drying treatment to remove most of the solvent component from the bonding agent, thereby forming a bonding layer on the surface of the first molded body.

[0050] <<Drying Treatment>> The conditions for the drying treatment are not particularly limited as long as the content of the solvent component in the bonded body obtained by this production method is within the above-mentioned predetermined trace concentration range (i.e., 100 ppm by mass or more and 800 ppm by mass or less). Furthermore, among such drying treatment conditions, a content ratio that forms a bonding layer having a thickness within the above-mentioned preferred range (e.g., 0.1 μm or more and 5 μm or less) is preferred.

[0051] The drying treatment may be carried out, for example, by drying at a temperature lower than the glass transition temperature of the cyclic olefin polymer that is the material of the bonding layer (e.g., heat drying, room temperature drying), heat vacuum (reduced pressure) drying, or a combination thereof. The drying treatment device is not particularly limited, and examples thereof include an oven (e.g., an inert gas hot air oven), a vacuum dryer, and a hot air drying furnace.

[0052] The temperature for the drying treatment is set to a temperature equal to or higher than the glass transition temperature (Tg １ ) is preferably at a temperature 10°C or more lower than the drying temperature. The temperature for the drying treatment is, for example, preferably 60°C or higher, more preferably 65°C or higher, even more preferably 70°C or higher, and preferably 128°C or lower, more preferably 125°C or lower, and even more preferably 122°C or lower. The time for the drying treatment is not particularly limited as long as drying can be performed sufficiently. However, if it is too long, industrial costs will increase and oxidation of the resin will progress, and in extreme cases, yellowing may occur. Therefore, for example, 1 second or more is preferable, 10 seconds or more is more preferable, 30 seconds or more is more preferable, and 55 minutes or less is preferable, 50 minutes or less is more preferable, and 40 minutes or less is even more preferable. The atmosphere for the drying treatment can be, for example, in the presence of air, in the presence of an inert gas, under vacuum, etc. From the viewpoint of suppressing deterioration of the components of the first molded body and the bonding layer due to the drying treatment and gently removing the solvent to suppress the generation of cavities in the bonding layer, the presence of an inert gas is preferred. Examples of the inert gas include rare gases (e.g., helium, neon, argon, krypton, and xenon), nitrogen gas, and the like.

[0053] <Step (iii): Bonding Step> In step (iii) (bonding step), a second molded body made of a thermoplastic resin is placed in contact with the bonding layer, and a heating and pressurizing treatment is performed to bond (thermally fuse) the first molded body and the second molded body via the bonding layer. When placing the second molded body, the first molded body and the second molded body may be temporarily fixed so that they are placed via the bonding layer to form a temporarily bonded bonded body. After the heating and pressurizing treatment, the bonded body can be obtained by cooling to room temperature.

[0054] <<Heat and pressure treatment>> The means for performing heat fusion by heat and pressure treatment is not particularly limited, but examples thereof include an autoclave, a heat press, a roll press, etc. Furthermore, when using an autoclave, a vacuum package obtained by vacuum-packaging the temporarily joined assembly may be treated in the autoclave. An example of vacuum packaging is vacuum packaging using a retort packaging material. Note that, before performing the heat and pressure treatment, it is preferable to remove trapped air from the temporarily joined assembly and then perform pressure bonding. However, since small amounts of air bubbles will disperse during autoclave processing, there is no problem as long as large amounts of air are not trapped.

[0055] The conditions for the heat and pressure treatment are not particularly limited as long as the conditions are such that the molded body and the bonding layer are bonded (thermally fused). The temperature for the heat and pressure treatment is set to a temperature below the glass transition temperature (Tg ２ ) and the glass transition temperature (Tg １ The temperature at which the heat and pressure treatment is carried out is preferably lower than both Tg ２ +5°C or higher is preferred, and Tg ２ The temperature at which heat fusion is performed is preferably Tg ２ +50°C or less is preferable, and Tg ２The temperature for the heat and pressure treatment is, for example, preferably 100°C or higher, more preferably 105°C or higher, and even more preferably 110°C or higher, and is preferably 140°C or lower, more preferably 135°C or lower, and even more preferably 130°C or lower. The pressure for the heat and pressure treatment is, for example, preferably 0.4 MPa or higher, more preferably 0.5 MPa or higher, and even more preferably 0.6 MPa or higher, and preferably 1.2 MPa or lower, more preferably 1.1 MPa or lower, and even more preferably 1.0 MPa or lower. The time for the heat and pressure treatment is, for example, preferably 10 minutes or longer, more preferably 15 minutes or longer, and even more preferably 18 minutes or longer, and is preferably 60 minutes or shorter, more preferably 50 minutes or shorter, and even more preferably 40 minutes or shorter. The amount of solvent in the bonded body finally obtained by this production method can be adjusted by the drying conditions in step (ii) and the heat and pressure treatment conditions in step (iii).

[0056] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0057] (Methods for measuring and evaluating physical properties) Measurement and evaluation of various physical properties were carried out according to the following methods.

[0058] <Method for measuring weight average molecular weight (Mw) and number average molecular weight (Mn) of COP> The weight average molecular weight (Mw) and number average molecular weight (Mn) of the cyclic olefin polymer (COP) were measured by gel permeation chromatography (GPC) using cyclohexane as an eluent, and were calculated as values ​​converted into standard polyisoprene. Standard polyisoprene manufactured by Tosoh Corporation was used as the standard polyisoprene. When the sample was not soluble in cyclohexane, it was measured by GPC using tetrahydrofuran (THF) as an eluent, and were calculated as values ​​converted into standard polystyrene. Standard polystyrene manufactured by Tosoh Corporation was used as the standard polystyrene.

[0059] <Method for Measuring Glass Transition Temperature of COP> The glass transition temperature (Tg) of a cyclic olefin polymer (COP) was measured using a differential scanning calorimeter (manufactured by Nano Technology Inc., product name: DSC6220SII) at a temperature rise rate of 10°C / min in accordance with JIS-K7121.

[0060] <Types and Contents of Solvent Components in COP: HS Gas Chromatography> The full-surface bonded joint (FIG. 1a) was cut into 3 mm x 3 mm pieces to prepare test pieces. The weight of each test piece was measured and placed in a headspace vial. An empty headspace vial was used as a "operation blank" for measurement, and a reference standard for conversion quantification (toluene-d8: 0.314 μg (10.5 μg / mL, 30 μL)) was added to the headspace vial, which was used as a "reference standard" for measurement. The measurement equipment used was a TurboMatrix 40 Trap (manufactured by PerkinElmer), a GCMS-QP2020 (manufactured by Shimadzu Corporation), and a column TC-BOND Q (0.25 mm ID × 30 m, 8 μm) (manufactured by GL Science). Detection was performed at a column temperature of 40°C (4 min) → 240°C (26 min), with a temperature rise rate of 10°C / min, and with a carrier gas of helium.

[0061] <Thickness of the bonding layer> The thickness of the bonding layer was measured using a full-surface bonded bonded body (Figure 1a). When the thickness was 0.5 μm or more, the thickness of the bonding layer (dry film thickness) was measured using a thickness gauge (HKT-Lite 0.1; Fujiwork Co., Ltd.) at the same location on the molded body before and after application, and the dry thickness of the bonding layer was measured by subtracting the thickness before application from the thickness after application. When the thickness of the bonding layer was less than 0.5 μm, the thickness (dry film thickness) of the bonding layer was measured by cutting a cross section from the molded body after drying with a microtome. The obtained cross-sectional section was subjected to platinum sputtering, and the cross section was observed using a scanning electron microscope (S-3400N; Hitachi High-Tech Corporation) to measure the thickness of the bonding layer.

[0062] <Flexural modulus: three-point bending measurement> A tension-compression load cell (capacity ±100 kN) was used in a universal material testing machine (Instron 5582, manufactured by Instron Corporation) with a three-point bending jig installed. A full-surface bonded joint 30 having a width (b) and thickness (h) bonded as shown in FIG. 1a was placed on two supports 41 of a material testing machine 40 as shown in FIG. 1b. The center of the full-surface bonded joint 30 was pressed from above with a pressing jig 42 (support distance (L) 55 mm, pressing speed 5 mm / min), and the flexural modulus was calculated from the initial gradient of the linear portion of the bending load-deflection curve. ΔF: change in bending load, Δs: change in deflection The amount of change is determined by selecting any two points from a close match.

[0063] <Bonding Strength: Three-Point Bending Measurement> A tension-compression load cell (capacity ±100 kN) was used in a universal material testing machine (Instron 5582, manufactured by Instron Corp.) with a three-point bending jig attached. The bonded body 20 for bonding strength measurement, which was bonded as shown in FIG. 2 a, was placed on two supports 41 of a material testing machine 40 as shown in FIG. 2 b. The central portion (overlap margin 22) of the bonded body 20 for bonding strength measurement was pressed from above with a pressing jig 42 (support distance 38 mm, pressing speed 10 mm / min), and the strength at break was determined.

[0064] <Transparency (Haze) After Sterilization Autoclave Treatment> <<Sterilization Autoclave Treatment: Wet Heat and Pressure Autoclave>> A full-surface bonded assembly sample was placed against an SUS fixture and inserted into an autoclave (SX-700; manufactured by Tomy Seiko Co., Ltd.), where it was sterilized at 121°C, 1.2 atm, and 15 minutes. When the temperature inside the autoclave dropped to 40°C or below, it was removed from the autoclave and air-dried at room temperature. <<Haze Measurement>> The bonded assembly sample was measured using a haze meter (NDH-700SP; manufactured by Nippon Denshoku Industries Co., Ltd.).

[0065] (1. Preparation of Cyclic Olefin Polymer (COP)) The cyclic olefin polymer (COP) used as the material for the molded body (injection molded plate) and the bonding layer was prepared by the following method.

[0066] <Preparation of COP-1> - Production of Ring-Opened Polymer - In a glass reactor whose interior had been purged with nitrogen, 200 parts by mass of dehydrated cyclohexane, 0.75 mol% 1-hexene, 0.15 mol% diisopropyl ether, and 0.44 mol% triisobutylaluminum were placed at room temperature and mixed relative to a total of 100 parts by mass of the monomers described below. Thereafter, while maintaining the temperature at 45°C, 33 parts by mass of dicyclopentadiene (DCPD), 36 parts by mass of norbornene (NB), and 31 parts by mass of tetracyclododecene (TCD) as monomers, and 0.02 mol% tungsten hexachloride (0.65 wt% toluene solution) were continuously added in parallel to the reactor over a period of 2 hours, and polymerization was carried out. Next, 0.2 mol% isopropyl alcohol was added to the polymerization solution to inactivate the polymerization catalyst and terminate the polymerization reaction. In the above description, the amounts indicated in the unit "mol %" are all values ​​with the total amount of monomers being 100 mol %.

[0067] —Production of Norbornene-Based Cyclic Olefin Polymer (COP-1) by Hydrogenation— Next, 300 parts by mass of the reaction solution containing the ring-opened polymer obtained above was transferred to an autoclave equipped with a stirrer, and 3 parts by mass of a diatomaceous earth-supported nickel catalyst ("T8400RL" manufactured by Nikki Chemical Industries, Ltd., nickel loading rate: 57%) was added. The mixture was autoclaved at a hydrogen pressure of 4.5 MPa and 160° C. for 4 hours to carry out a hydrogenation reaction.

[0068] After completion of the hydrogenation reaction, the resulting solution was pressure filtered ("Fundaback filter" manufactured by Ishikawajima-Harima Heavy Industries, Ltd.) at a pressure of 0.25 MPa using Radiolite #500 as a filter bed to remove the hydrogenation catalyst, yielding a colorless, transparent solution. The resulting solution was poured into a large amount of isopropanol to precipitate a norbornene-based cyclic olefin polymer (COP-1) as a hydrogenated product of the ring-opening polymer. The precipitated norbornene-based cyclic olefin polymer (COP-1) was collected by filtration and then dried in a vacuum dryer (220°C, 1 Torr) for 6 hours to yield a norbornene-based cyclic olefin polymer (COP-1). The norbornene-based cyclic olefin polymer (COP-1) had a weight average molecular weight (Mw) of 41,500 and a number average molecular weight (Mn) of 13,500.

[0069] The glass transition temperature (Tg) of the resulting norbornene-based cyclic olefin polymer (COP-1) was 68°C.

[0070] -Production of thermoplastic norbornene-based resin pellets- The norbornene-based cyclic olefin polymer (COP-1) obtained above was fed into a twin-screw extruder and molded into a strand-like molded body by hot-melt extrusion molding. This molded body was shredded using a strand cutter to obtain pellets of a thermoplastic norbornene-based resin containing the norbornene-based cyclic olefin polymer (COP-1).

[0071] <Preparation of COP-2> A norbornene-based cyclic olefin polymer (COP-2) was synthesized in the same manner as in the production of COP-1, except that 38.2 parts by mass of dicyclopentadiene (DCPD), 26.8 parts by mass of methanotetrahydrofluorene (MTF), and 35 parts by mass of tetracyclododecene (TCD) were used as monomers, and pellets of a thermoplastic norbornene-based resin containing COP-2 were obtained. The weight-average molecular weight (Mw) of COP-2 was 33,000 and the number-average molecular weight (Mn) was 15,500. The glass transition temperature (Tg) of COP-2 was 138°C.

[0072] <Preparation of COP-3> A norbornene-based cyclic olefin polymer (COP-3) was synthesized in the same manner as in the production of COP-1, except that 60 parts by mass of methanotetrahydrofluorene (MTF) and 40 parts by mass of tetracyclododecene (TCD) were used as monomers, and pellets of a thermoplastic norbornene-based resin containing COP-3 were obtained. The weight-average molecular weight (Mw) of COP-3 was 32,000 and the number-average molecular weight (Mn) was 19,000. The glass transition temperature (Tg) of COP-3 was 159°C.

[0073] <Preparation of COP-4> A norbornene-based cyclic olefin polymer (COP-4) was synthesized in the same manner as in the production of COP-1, except that 100 parts by mass of ethylidenetetracyclododecene (ETD) was used as the monomer, and pellets of a thermoplastic norbornene-based resin containing COP-4 were obtained. The weight-average molecular weight (Mw) of COP-4 was 40,000 and the number-average molecular weight (Mn) was 19,500. The glass transition temperature (Tg) of COP-4 was 138°C.

[0074] (2. Preparation of Molded Articles (Injection-Molded Plates)) As the molded articles used in Examples 1 to 10 and Comparative Examples 1 to 10, injection-molded plates (injection-molded plate A, injection-molded plate B) made from the resins for molded articles shown in Table 1 were prepared by attaching a plate molding mold having a thickness of 2 mm, a width of 25 mm, and a length of 75 mm to an injection molding machine (ROBOSHOT S2000i100A manufactured by FANUC) and performing injection molding at a mold temperature of 80 ° C. and a barrel temperature of 270 ° C. The injection-molded plates had a flat plate shape having a thickness of 2 mm, a width of 25 mm, and a length of 75 mm. Injection-molded plates A and B were prepared for preparing a full-surface bonded joint and for measuring bonding strength, respectively. In Examples 1 to 6, 8, and Comparative Examples 1 to 10, injection-molded plates A and B were prepared using the same type of resin. When COP (COP-2, COP-3) was used as the resin, resin pellets dried at Tg-20°C for 5 hours were used as the resin for the molded body. When polymethyl methacrylate (PMMA) was used as the resin (Example 10), an injection-molded plate that had been corona discharge treated after molding was used.

[0075] Corona Discharge Treatment: The injection-molded plate B made of PMMA used in Example 10 was subjected to a corona discharge treatment as follows. Using a table-type corona discharge treatment device (CTW-0212; manufactured by Wedge Corporation), the molded body was placed on a movable table and subjected to one round trip of corona discharge treatment at an output of 0.3 kW, a treatment speed of 3 m / min, and an electrode distance of 12 mm. After the corona discharge treatment, the molded body was removed and subjected to static elimination treatment using an ionizer.

[0076] (3. Formation of Bonding Layer) <Preparation of Bonding Agent> The bonding agents used in Examples 1 to 10 and Comparative Examples 1 to 10 were prepared as follows. The solvent and resin (COP) pellets shown in Table 1 were weighed into a sealed container, and after sealing, the container was shaken at 100 rpm for 4 hours at 25°C using a shaker (MMS-1020; manufactured by Tokyo Rikakiki) to dissolve the resin in the solvent. After dissolution, the solution was filtered, and the filtrate was collected and used as a bonding agent (coating solution).

[0077] <Application of adhesive> To prepare a full-surface bonded joint, the adhesive prepared above was applied to the entire surface of one side of injection-molded plate A (a surface measuring 25 mm wide x 75 mm long; hereinafter, also referred to as the "coated surface"). To prepare a joint for measuring bonding strength, the adhesive prepared above was applied to an area extending 5 mm from the end of the short side of one side of injection-molded plate A (hereinafter, referred to as the "overlap margin"). The adhesive was applied by bar coating, silk screening, or spin coating, as shown in Table 1.

[0078] - Bar coating method - Using a Mayer bar (wire bar; manufactured by Marukyo Giken), the adhesive was scraped off and coated onto the application surface of injection-molded plate A. Injection-molded plate A coated with the adhesive was removed and placed in a drying oven, where it was dried at the specified temperature and for the specified time as described below.

[0079] - Silkscreen method - A SUS screen mesh (500 mesh, wire diameter 18 μmφ, opening 29 μm; manufactured by Sonocom Corporation) was attached to a tabletop screen printing machine (HP-320; manufactured by Newlong Precision Industry Co., Ltd.), and injection-molded plate A was placed on a suction fixing table and fixed by suction. Adhesive agent was dropped onto the SUS screen mesh and scraped off with a squeegee, and a predetermined amount of adhesive agent was applied to the coated surface of injection-molded plate A. After application, the suction mounting was stopped, and the injection-molded plate coated with adhesive was removed and placed in a drying oven, where it was dried at the predetermined temperature and for the predetermined time as described below.

[0080] -Spin Coating Method- Using a spin coater (ACT-220DII; manufactured by Active Corporation), the injection-molded plate was suction-fixed in the chamber, and 5 mL of bonding agent was dropped onto the center of the coating surface of injection-molded plate A. The chamber was closed, and spin coating was performed at 2000 rpm at room temperature. After coating was completed, the suction fixation was stopped, and injection-molded plate A coated with bonding agent was removed and placed in a drying oven, where it was dried at the specified temperature and for the specified time as described below.

[0081] <Drying Treatment> The coated sample was placed in a small inert gas oven (KLO-30NH; manufactured by Koyo Thermo Systems Co., Ltd.) and dried at the predetermined temperature and time shown in Table 1 to remove the solvent from the coated bonding agent, thereby forming a bonding layer on the coated surface of the injection-molded plate A (on the entire surface for producing a full-surface bonded bonded body, and in the overlapping area for measuring the bonding strength).

[0082] (4. Preparation of bonded specimens by bonding molded bodies (injection-molded plates)) Injection-molded plate B was bonded to injection-molded plate A, on which a bonding layer had been formed, to prepare bonded specimens in which injection-molded plate A and injection-molded plate B were bonded via the bonding layer. As the bonded specimens, a full-surface bonded joint (Fig. 1a) and a joint for measuring bonding strength (Fig. 2a) were prepared. Bonding was performed by autoclave treatment (heating and pressurizing air).

[0083] <Bonding autoclave (air heating and pressurization) treatment> For the full-surface bonded bonded body (Figure 1a), an injection-molded plate A with a bonding layer formed on the entire coated surface and an injection-molded plate B with no bonding agent applied were stacked and temporarily fixed in a direction that they would contact each other via the bonding layer at a position where the injection-molded plates overlapped completely, to obtain a temporarily bonded bonded body. For the bonded body for bonding strength measurement (Figure 2a), an injection-molded plate A with a bonding layer formed on the overlapping margin of the coated surface and an injection-molded plate B with no bonding agent applied were stacked and temporarily fixed in a direction that they would contact each other via the bonding layer at a position where the injection-molded plates overlapped each other at the overlapping margin, to obtain a temporarily bonded bonded body.

[0084] The temporarily bonded assembly was vacuum-packaged using a vacuum packaging machine (T100 manufactured by Nippon Packaging Machinery Co., Ltd.) with retort packaging material. This vacuum-packaged assembly was placed in an autoclave (Tandelion DL-2010 manufactured by Hanyuda Iron Works Co., Ltd.) and heated and pressurized at a temperature of 120°C, a pressure of 0.8 MPa, and a pressure time of 30 minutes to bond injection-molded plate A and injection-molded plate B via the bonding layer, thereby forming a bonded assembly test piece. After completion of the autoclave, the assembly was cooled to room temperature and removed (full-surface bonded assembly or bonded assembly for bond strength measurement).

[0085] As shown in Figure 1a, the full-surface bonded joint 30 was a joint in which injection-molded plate A (21) and injection-molded plate B (21) were joined at a position where the injection-molded plates overlapped on their entire surfaces via a bonding layer 13. As shown in Figure 2a, the joint 20 for bond strength measurement was a joint in which injection-molded plate A (21) and injection-molded plate B (21) were joined via a bonding layer 13 with an overlap margin 22 (where the injection-molded plates overlap) up to 5 mm from the end of the short side.

[0086] <Various measurements and evaluations> The solvent extractable amount, transparency (haze) after sterilization in an autoclave, and flexural modulus were measured using the full-surface bonded assembly (Fig. 1a). The bond strength was measured using the bonded assembly for bond strength measurement (Fig. 2). The results are shown in Table 1.

[0087]

[0088] According to the present invention, it is possible to provide a bonded body that is excellent in flexural modulus and bonding strength and that is inhibited from losing transparency due to an increase in haze under the generation of water vapor, and a method for producing the same.

[0089] 13 Bonding agent 20 Bonded body for measuring bonding strength 21 Molded body 22 Overlap margin 30 Full-surface bonded bonded body 40 Material testing machine 41 Support 42 Pressing jig

Claims

1. A bonded body comprising a plurality of molded bodies made of a thermoplastic resin material and a bonding layer that bonds the molded bodies together, the bonding layer contains at least one kind of cyclic olefin polymer and a solvent component having a boiling point of 70°C or more and 150°C or less; the bonded body contains a solvent component having a boiling point of 70°C or higher and 150°C or lower in an amount of 100 ppm by mass or higher and 800 ppm by mass or lower based on the total mass of the bonded body; zygote.

2. The bonded body according to claim 1 , wherein the bonding layer has a thickness of 0.1 μm or more and 5 μm or less.

3. 2. The joined body according to claim 1, wherein the thermoplastic resin is a resin containing a cyclic olefin polymer.

4. A joint body as described in claim 2, wherein the thermoplastic resin is a resin containing a cyclic olefin polymer.

5. 5. The conjugate according to claim 1, wherein the solvent component comprises at least one of cyclohexane, methylcyclohexane, ethylcyclohexane, xylene, and toluene.

6. A method for producing a bonded body according to any one of claims 1 to 4, comprising the steps of: a step of applying a bonding agent containing at least one type of cyclic olefin polymer and a solvent component having a boiling point of 70°C or higher and 150°C or lower onto at least one surface of a first molded body made of a thermoplastic resin; a step of performing a drying process on the applied bonding agent to remove most of the solvent component from the bonding agent and form a bonding layer on the surface of the first molded body; a step of arranging a second molded body made of a thermoplastic resin so as to be in contact with the bonding layer, and performing a heating and pressurizing treatment to bond the first molded body and the second molded body via the bonding layer, thereby obtaining a bonded body containing a solvent component in an amount of 100 ppm by mass or more and 800 ppm by mass or less with respect to the total mass of the bonded body; Including, A method for manufacturing a bonded body.