Bonded body and manufacturing method therefor

Abstract

This bonded body is obtained by bonding, with a bonding layer, a plurality of molded bodies using a thermoplastic resin as a material, wherein: at least one among the plurality of molded bodies has a three-dimensional structure on at least one surface thereof; the three-dimensional structure has a surface provided with the bonding layer; the bonding layer contains at least one cyclic olefin polymer and a solvent having a boiling point of 70-150ºC; and said bonded body contains less than 100 ppm by mass of the solvent having a boiling point of 70-150ºC with respect to the total mass of said bonded body.

Description

Joint and manufacturing method thereof

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

[0002] Disclosed is a conjugated structure that includes a plurality of molded bodies made of a thermoplastic resin and a bonding layer that bonds the molded bodies together, and that serves as a microchannel chip used for the analysis, testing, etc. of biological materials such as DNA, RNA, and proteins, as well as chemical substances. The bonding layer contains a cyclic olefin polymer and a solvent component having a boiling point within a certain range, and the content of the solvent component is 100 ppm by mass or more and 800 ppm by mass or less with respect to the total mass of the conjugated structure (see, for example, Patent Document 1).

[0003] It is also disclosed that when a substrate is coated with a coating material containing a cyclic olefin-based addition polymer and dried to form a coating layer, the coating layer is dried until the residual solvent contained in the coating layer is 2% by weight or less (see, for example, Patent Document 2).

[0004] Furthermore, it is described that when producing a resin laminate such as a laminate film or a pressure-sensitive adhesive tape, 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 (see, for example, Patent Documents 3 and 4).

[0005] International Publication No. 2023 / 189188 Japanese Patent Application Laid-Open No. 2004-058339 Japanese Patent Application Laid-Open No. 2007-276142 Japanese Patent Application Laid-Open No. 2003-306650

[0006] Techniques for producing resin joined bodies formed by joining multiple resin molded bodies via a joining layer are expected to be applied to devices used in biological or chemical analysis, such as microchannel chips and multiwell plates. Such resin joined bodies are required to have a reduced amount of residual solvent that may leach out during use of the joined body, as well as excellent shape precision of three-dimensional structures such as flow channels. However, the above-mentioned conventional techniques leave room for improvement in terms of both reducing residual solvent and improving the shape precision of three-dimensional structures. Therefore, an object of the present invention is to provide a joined body with a low amount of residual solvent and excellent shape precision, and a method for producing the same.

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and have newly discovered that a joined body is obtained by joining a plurality of molded bodies made of a thermoplastic resin with a bonding layer, at least one of the molded bodies having a three-dimensional structure on at least one surface, the three-dimensional structure having a bonding layer on a surface thereof, the bonding layer including at least one type of cyclic olefin polymer and a solvent having a boiling point within a predetermined range, and the joined body includes the solvent having a boiling point within a predetermined range at a predetermined trace concentration, thereby achieving a joined body with a small amount of residual solvent and excellent shape precision, and have completed the present invention.

[0008] That is, the present invention aims to advantageously solve the above-mentioned problems, and the present invention provides: [1] a bonded structure formed by bonding multiple molded bodies made of a thermoplastic resin with a bonding layer, wherein at least one of the multiple molded bodies has a three-dimensional structure on at least one side, and the three-dimensional structure has the bonding layer on its surface, and the bonding layer includes at least one type of cyclic olefin polymer and a solvent having a boiling point of 70°C or higher and 150°C or lower, and the bonded structure contains the solvent having a boiling point of 70°C or higher and 150°C or lower in a proportion of less than 100 ppm by mass relative to the total mass of the bonded structure. By including a solvent having a boiling point within a predetermined range in the bonding layer so that the solvent content in the bonded structure is a predetermined trace concentration, the bonded structure can have little residual solvent and excellent shape precision. The solvent content in the bonded structure can be measured, for example, by the method described in the Examples. Furthermore, the presence of a bonding layer on the surface of the three-dimensional structure can be confirmed by cutting the bonded structure and observing the cross section with a microscope, etc. Furthermore, the boiling point of the solvent refers to the boiling point at 1 atm.

[0009] [2] Here, in the bonded body of the above [1], the three-dimensional structure of the molded body is preferably a recess or a through-hole.

[0010] [3] In the bonded structure of [1] or [2], the at least one cyclic olefin polymer contained in the bonding layer is preferably at least one hydrogenated cyclic olefin polymer. Hydrogenated cyclic olefin polymers have excellent light transmittance and are particularly less susceptible to yellowing and strength loss due to ultraviolet light, and therefore, when used as a material for the bonding layer, they can impart excellent durability to the bonded structure.

[0011] [4] In the joined body of [3], the at least one hydrogenated cyclic olefin polymer contained in the joining layer is preferably a hydrogenated ring-opening polymer of a norbornene-based monomer. If the hydrogenated cyclic olefin polymer is a hydrogenated ring-opening polymer of a norbornene-based monomer, the joined body can be excellent in heat resistance, chemical resistance, and light transmittance.

[0012] [5] In the bonded structure according to any one of [1] to [4] above, the thickness of the bonding layer is preferably 0.05 μm or more and 5 μm or less. If the thickness of the bonding layer is within this range, the bonding strength of the bonding layer is ensured, the amount of solvent contained in the bonding layer is reduced, leakage of the bonding layer into the flow path is minimized, and the bonded structure can have excellent shape precision. The thickness of the bonding layer can be measured by the method described in the Examples.

[0013] [6] In the bonded structure of any one of [1] to [5] above, the thermoplastic resin is preferably a resin containing a cyclic olefin polymer. By including a cyclic olefin polymer in the thermoplastic resin, the bonded structure can be endowed with excellent properties such as heat resistance and dimensional stability. Furthermore, since the thermoplastic resin is a type of polymer in the same category as the cyclic olefin polymer that is the material of the bonding layer, they can be easily fused to each other, thereby imparting excellent bonding strength to the bonded structure.

[0014] [7] In the bonded structure according to any one of [1] to [6] above, the solvent preferably contains at least one of cyclohexane, methylcyclohexane, ethylcyclohexane, xylene, and toluene. These solvents have high solubility for cyclic olefin polymers, making it possible to obtain a bonding layer with excellent uniformity. The type of solvent can be identified, for example, by the method described in the Examples.

[0015] [8] The present invention also provides a method for producing a bonded body, the method comprising the steps of: applying a bonding agent containing at least one type of cyclic olefin polymer and a solvent having a boiling point of 70°C or higher and 150°C or lower to at least one surface of a molded body A, which is at least one molded body among a plurality of molded bodies made from a thermoplastic resin; drying the applied bonding agent to form a bonding layer on the at least one surface of the molded body A; vacuum-heat-pressing the molded body A at a temperature at least 20°C higher than the glass transition temperature of the thermoplastic resin constituting the molded body A to form a three-dimensional structure on the surface of the molded body A having the bonding layer; and disposing a molded body B, which is another molded body different from the molded body A among the plurality of molded bodies, so as to be in contact with the bonding layer, and performing a heat-pressure treatment to bond the molded body A and the molded body B together via the bonding layer to obtain a bonded body. By forming a bonding layer using a bonding agent containing a solvent with a boiling point within a predetermined range and then subjecting the surface of the molded body A having the bonding layer to reduced pressure and heat pressing to form a three-dimensional structure, the resulting bonded body can have little residual solvent and excellent shape precision.

[0016] According to the present invention, it is possible to provide a bonded body having a small amount of residual solvent and excellent shape precision, and a method for producing the same.

[0017] 1 shows an example of a method for manufacturing a bonded body of the present invention. A full-surface bonded bonded body 30 used for measuring flexural modulus is shown, with a side view on the top and a top view on the bottom. A schematic diagram of flexural modulus measurement is shown. A bonded body 20 for bonding strength measurement used for measuring bonding strength is shown, with a side view on the top and a top view on the bottom. A schematic diagram of bonding strength measurement is shown.

[0018] Hereinafter, embodiments of the present invention will be described in detail.

[0019] (Jointed Structure) The joined structure of the present invention is a joined structure formed by bonding multiple molded bodies made of a thermoplastic resin with a bonding layer, wherein at least one of the multiple molded bodies has a three-dimensional structure on at least one side, the three-dimensional structure having a bonding layer on its surface, the bonding layer including at least one type of cyclic olefin polymer and a solvent having a boiling point within a predetermined range, and the joined structure includes the solvent having a boiling point within a predetermined range at a predetermined trace concentration. The predetermined boiling point range must be between 70°C and 150°C. The predetermined trace concentration must be less than 100 ppm by mass relative to the total mass of the joined structure. By having the solvent content within the above range, the joined structure can be obtained with minimal residual solvent that may leach out during use and with excellent shape precision. Here, the fact that the three-dimensional structure has a bonding layer on its surface, in other words, that the bonding layer included in the joined structure is derived from a joined body having a three-dimensional structure, can be confirmed by the method described in the Examples. The shape accuracy of the bonded body can be evaluated by cutting a molded body having a three-dimensional structure before bonding and a bonded body obtained by bonding the molded bodies at the same position on the three-dimensional structure and measuring the rate of change in cross-sectional area. When evaluating the shape accuracy, for example, except for when the three-dimensional structure to be evaluated is a planar, band-shaped channel as in the examples described below, the cut surface for evaluating the shape accuracy is not particularly limited as long as it is a cross-section obtained by cutting the three-dimensional structure in a direction approximately corresponding to the bonding direction. If the solvent content in the bonded body is less than the above upper limit, melting of the surface of the molded body when applying the bonding agent described below to the molded body and deformation of the bonding layer during heating in the production of the bonded body can be reduced, thereby reducing deformation such as rounding of the corners of microstructures such as channels, and improving the shape accuracy.

[0020] <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 particularly preferably a device for analysis, testing, etc., such as a microchannel chip or multiwell plate, which requires excellent shape precision.

[0021] <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.

[0022] The molded article can be formed, for example, by injection molding of a resin. Furthermore, after the formation of the bonding layer, the molded article can be subjected to a reduced pressure hot press, as described below, to form a three-dimensional structure on the surface of the molded article having the bonding layer by surface shaping. The three-dimensional structure formed on the surface may be a microstructure. The three-dimensional structure is not particularly limited, but may be, for example, a recess such as a flow channel or well, or a through-hole. Furthermore, when the assembly is a multi-well plate, the structure formed on the surface may be, for example, a recess in a well, or a through-hole forming the wall of the well. The molded article, such as a lid substrate, that does not have the above three-dimensional structure can be formed using known techniques such as vacuum hot press molding, extrusion molding, injection molding, and cutting.

[0023] <<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 material for the molded body, when the molded bodies are bonded together via a bonding layer by a heating and pressurizing treatment, the bonding interface of the molded bodies becomes more compatible with the 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.

[0024] If a cyclic olefin polymer is used as the thermoplastic resin, it will be of the same category as the cyclic olefin polymer used as the material for the bonding layer, and therefore they will be easily fused to each other, thereby imparting even better bonding strength to the bonded body. Furthermore, since cyclic olefin polymers are resins with excellent heat resistance, dimensional stability, acid resistance, alkali resistance, hydrolysis resistance, light weight, and ease of resin molding, they can impart excellent properties to the bonded body. In particular, since cyclic olefin polymers exhibit little decrease in bonding strength over time and little dimensional change due to moisture absorption, they are suitable as a material for molded bodies that imparts excellent durability to the bonded body. Furthermore, since cyclic olefin polymers are transparent and have low autofluorescence, they are suitable when the bonded body is used in optical signal detection devices such as microchannel chips and multiwell plates. Furthermore, the glass transition temperature (Tg １ ) will be discussed later.

[0025] <<Thickness of Molded Article>> The thickness of the molded article 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.

[0026] <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 having a boiling point within a predetermined range, such that the content of the solvent in the bonded body is a predetermined trace concentration. The predetermined boiling point range must be 70°C or higher and 150°C or lower. The predetermined trace concentration must be a ratio of less than 100 ppm by mass with respect to the total mass of the bonded body. By containing a solvent having a boiling point within a predetermined range in the bonded body, such that the content of the solvent in the bonded body is a predetermined trace concentration, the bonded body can be made to have little residual solvent and excellent shape precision.

[0027] <<Main Material of Bonding Layer: Cyclic Olefin Polymer>> The bonding layer contains at least one type of 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. Preferably, at least one type of cyclic olefin polymer contained in the bonding layer is a hydrogenated product of at least one type of cyclic olefin polymer. Hydrogenated cyclic olefin polymers have excellent light transmittance and are particularly resistant to yellowing and strength reduction due to ultraviolet rays, making them suitable as bonding layer materials that impart excellent durability to the bonded body. Furthermore, as described above, the hydrogenated cyclic olefin polymer is a material with excellent light transmittance and low autofluorescence, and therefore is suitable for use in optical signal detection devices such as microchannel chips and multiwell plates. ２ ) will be discussed later.

[0028] <<Thickness of 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, and may be, for example, 0.05 μm or more, preferably 0.12 μm or more, more preferably 0.15 μm or more, and even more preferably 0.20 μm or more. The thickness of the bonding layer may be, for example, 5.0 μm or less, preferably 4.5 μm or less, more preferably 4.2 μm or less, and even more preferably 4.0 μm or less. It is preferable that the thickness of the bonding layer does not exceed the upper limit. The thinner the bonding layer, the less solvent is contained in the bonding layer, resulting in excellent shape accuracy of the bonded body. Conversely, if the thickness of the bonding layer is thinner than the lower limit, the effect of the bonding layer on the bonding strength is reduced. When the bonded body includes multiple bonding layers, at least one bonding layer may be within the above range, and it is preferable that all bonding layers be within the above range. The thickness of the bonding layer can be controlled by adjusting the content of the cyclic olefin polymer in the bonding agent containing the cyclic olefin polymer and a solvent used to form the bonding layer, the amount of bonding agent applied and other application conditions, as well as the drying conditions for removing the solvent when forming the bonding layer and the conditions of the reduced pressure hot pressing described below (e.g., temperature, time, pressure, etc.). The thickness of the bonding layer can be measured, for example, by the method described in the Examples.

[0029] <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 monomer 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.

[0030] The ring-opening polymer 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. The ring-opening polymer 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 polymer 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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, preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 200,000 or less, and particularly preferably 100,000 or less. The number average molecular weight (Mn) of the cyclic olefin polymer that can be used as a material for the molded body and the bonding layer is preferably 1,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 100,000 or less, and particularly preferably 50,000 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.

[0035] <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.

[0036] Tg １ is preferably 125°C or higher, more preferably 130°C or higher. １ When Tg is in this range, softening, deformation, and deterioration of the molded article due to heating during production of the bonded article and optional sterilization (e.g., autoclave) can be suppressed, and a bonded article with excellent shape precision can be provided. 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), more preferably 30°C or higher (i.e., Tg １ ≧Tg ２ +30°C), and more preferably 40°C or higher (i.e., Tg １ ≧Tg ２ +40°C) is particularly 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.

[0037] 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.

[0038] In the present invention, the glass transition temperature can be measured by differential scanning calorimetry (DSC) based on JIS-K7121.

[0039] 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. In addition, when the bonding layer contains two or more types of resin components, 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 and the weighted average glass transition temperature of the two or more resin components constituting the bonding layer) preferably satisfies the following relationship: Tg １ >Tg ２ The weighted average glass transition temperature can be calculated by the following equation: Weighted average Tg = X1Y1+X2Y2+ ... +XnYn, where X1, X2, ..., Xn are the Tgs of the resin components constituting the bonding layer, respectively, and Y1, Y2, ..., Yn are the blending ratios of the resin components constituting the bonding layer (Y1+Y2+ ... +Yn = 1.0). Here, n is a number indicating the number of types of resin components constituting the bonding layer. For example, if the bonding layer contains two types of resin components, n is 2.

[0040] 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.

[0041] <Solvent> The bonded body contains a solvent with a boiling point within a predetermined range as a trace component. The bonding layer of the bonded body is usually formed during the production of the bonded body by applying a bonding agent, in which a cyclic olefin polymer, the main material of the bonding layer, is dissolved in a solvent, to at least one surface of the molded body and then drying the applied bonding agent. The solvent is not particularly limited as long as it is a substance used as a solvent for the cyclic olefin polymer, the main material of the bonding layer, and has a boiling point within a predetermined range. The solvent 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). 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. 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 preferably includes at least one of cyclohexane, methylcyclohexane, ethylcyclohexane, xylene, and toluene.

[0042] <<Solvent Content>> The bonded structure contains a solvent at a predetermined trace concentration. The predetermined trace concentration means that the solvent content relative to the total mass of the bonded structure must be less than 100 ppm by mass, preferably 90 ppm by mass or less, and more preferably 85 ppm by mass or less. The solvent content relative to the total mass of the bonded structure is preferably 5 ppm by mass or more, more preferably 7 ppm by mass or more, even more preferably 10 ppm by mass or more, still more preferably 12 ppm by mass or more, and particularly preferably 15 ppm by mass or more.

[0043] If the solvent content ratio relative to the total mass of the bonded body is less than the above upper limit, the solvent contained in the bonding layer can reduce melting of the surface of the molded body when the bonding agent is applied to the molded body and deformation of the bonding layer during heating in the manufacturing of the bonded body, thereby improving the shape accuracy of the three-dimensional structure in the bonded body. On the other hand, if the solvent content ratio relative to the total mass of the bonded body is equal to or greater than the above lower limit, the bonding layer can be imparted with appropriate flexibility and fluidity, resulting in a bonded body with excellent bending elasticity and bonding strength between the molded bodies. The solvent content ratio in the bonded body can be measured, for example, by the method described in the Examples.

[0044] <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.

[0045] 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.

[0046] (Method for manufacturing a bonded body) The method for manufacturing a bonded body of the present invention is characterized by comprising the following steps: (i) a step of applying a bonding agent containing at least one type of cyclic olefin polymer and a solvent having a boiling point within a predetermined range to at least one surface of molded body A, which is at least one molded body among a plurality of molded bodies made from a thermoplastic resin (bonding agent application step); (ii) a step of drying the applied bonding agent to form a bonding layer on at least one surface of molded body A (bonding layer formation step); (iii) a step of vacuum-heat-pressing molded body A at a temperature at least 20°C higher than the glass transition temperature of the thermoplastic resin constituting molded body A to form a three-dimensional structure on the surface of molded body A having the bonding layer (surface shaping step); and (iv) a step of arranging molded body B, which is another molded body different from molded body A among the plurality of molded bodies, so as to be in contact with the bonding layer, and performing a heating and pressurizing treatment to bond molded body A and molded body B via the bonding layer, thereby obtaining a bonded body (bonding step). An example of the manufacturing method of the bonded body of the present invention as described above will be specifically described later with reference to FIG. 1. The predetermined boiling point range must be 70°C or higher and 150°C or lower. The predetermined trace concentration must be a ratio of less than 100 mass ppm with respect to the total mass of the bonded body. By forming a bonding layer using a bonding agent containing a solvent with a boiling point within the predetermined range and then subjecting the surface of the molded body A having the bonding layer to reduced pressure and hot pressing to form a three-dimensional structure, the resulting bonded body can have little residual solvent and excellent shape precision.

[0047] The bonded body obtained by the method for producing a bonded body of the present invention has a structure in which a molded body A and a molded body B are bonded via a bonding layer. When producing a bonded body in which three or more molded bodies are stacked, an additional bonding layer different from the above-mentioned bonding layer may be formed on at least one of two layers of the three or more molded bodies, i.e., molded body A and molded body B, and an additional molded body (a molded body other than the molded body A and the molded body B) may be stacked and bonded one or more times.

[0048] <Step (i): Binder application step> In step (i) (binder application step), a binder containing at least one type of cyclic olefin polymer and a solvent having a boiling point within a predetermined range is applied to at least one surface of the molded body A made of a thermoplastic resin.

[0049] <<Bonding Agent>> The "bonding agent" refers to a coating liquid applied to the molded body A in step (i) to form a bonding layer. The bonding agent contains at least one type of cyclic olefin polymer and a solvent having a boiling point within a predetermined range. The cyclic olefin polymer and solvent used as components of the bonding layer are the same as those used as components of the bonding layer. The content of the cyclic olefin polymer in the bonding agent is not particularly limited as long as the content of the solvent in the bonded body obtained by this production method falls within the above-mentioned predetermined trace concentration (i.e., less than 100 ppm by mass). Furthermore, among such content ratios, a content ratio that allows the formation of a bonding layer having a thickness within the above-mentioned preferred range (e.g., 0.05 μm or more and 5.0 μm or less) in step (ii) is preferred. The content of the cyclic olefin polymer 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 the solvent by drying, it is preferable that the content of the cyclic olefin polymer in the bonding agent is not too low, and in order to impart sufficient solubility to the bonding agent and improve uniformity and ease of application, it is preferable that the content of the cyclic olefin polymer in the bonding agent is not too high.

[0050] <<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.

[0051] <Step (ii): Bonding layer forming step> In step (ii) (bonding layer forming step), the bonding agent applied to at least one surface of the molded body A is subjected to a drying treatment to form a bonding layer on the surface of the molded body A.

[0052] <<Drying Treatment>> The conditions for the drying treatment are not particularly limited as long as the solvent content in the bonded body obtained by this production method is the above-mentioned predetermined trace concentration (i.e., less than 100 ppm by mass). Furthermore, among such drying treatment conditions, a content that allows the formation of a bonding layer having a thickness in the above-mentioned preferred range (e.g., 0.05 μm or more and 5.0 μm or less) is preferred.

[0053] The drying treatment is carried out after the glass transition temperature (Tg １ ), drying at a temperature higher than the glass transition temperature of the cyclic olefin polymer that is the material for the bonding layer (e.g., drying by heating, drying at room temperature), drying by heating in a vacuum (reduced pressure), or a combination thereof may be used. The drying apparatus 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.

[0054] The temperature for the drying treatment is the glass transition temperature (Tg １ ) of the molded body A is preferably at least 10°C lower than the glass transition temperature (Tg １ ) is more preferably at a temperature 15°C or more lower than the glass transition temperature (Tg １) is more preferably a temperature 20 ° 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, and even more preferably 70 ° C. or higher. Also, 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. Examples of the atmosphere for the drying treatment include air, inert gas, and vacuum. From the viewpoint of suppressing deterioration of the components of the molded body A 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.

[0055] <Step (iii): Surface shaping step> In step (iii) (surface shaping step), the molded body A is subjected to reduced pressure heat pressing at a temperature at least 20°C higher than the glass transition temperature of the thermoplastic resin constituting the molded body A, to form a three-dimensional structure on the surface of the molded body A having the bonding layer.

[0056] <<Decompression Heat Pressing>> The reduction-pressing heat press can be performed, for example, by placing the molded body A on which the bonding layer has been formed in step (ii) in a mold and pressing it under pressure using a commercially available heat press. During the reduction-pressing heat press, a three-dimensional structure can be formed on the surface of the molded body A having the bonding layer by pressing the surface with a mold having a desired shape. The three-dimensional structure is not particularly limited, but may be, for example, a recess such as a flow channel or well, or a through-hole. By performing the reduction-pressing heat press as described above, the residual solvent in the bonding layer can be evaporated, further reducing the solvent content in the bonded body finally obtained by this manufacturing method, and the bonded body obtained by this manufacturing method can have excellent shape precision.

[0057] The temperature at which the vacuum hot pressing is carried out is the glass transition temperature (Tg １ ) +20°C or higher, and Tg １ The temperature at which the reduced pressure hot pressing is carried out is preferably Tg １ +160°C or less is preferable, and Tg １ +130°C or less is more preferable. The pressure applied when performing the reduced pressure hot pressing is, for example, preferably 1 MPa or more, more preferably 3 MPa or more, even more preferably 4 MPa or more, and preferably 10 MPa or less, more preferably 8 MPa or less, and even more preferably 7 MPa or less. The time for performing the reduced pressure hot pressing is, for example, preferably 1 minute or more, more preferably 3 minutes or more, even more preferably 5 minutes or more, and preferably 25 minutes or less, more preferably 20 minutes or less, and even more preferably 15 minutes or less. The ultimate pressure for vacuuming in the reduced pressure hot pressing is, for example, preferably 10,000 Pa or less, more preferably 1,000 Pa or less, and even more preferably 100 Pa or less. When the temperature, applied pressure, vacuum pressure, and time for performing the reduced pressure hot pressing are each within the above-mentioned ranges, the content of the solvent in the bonded body finally obtained by this production method can be set to the above-mentioned predetermined trace concentration (i.e., less than 100 ppm by mass).

[0058] <Step (iv): Bonding Step> In step (iv) (bonding step), a molded body B made of a thermoplastic resin is placed so as to be in contact with the bonding layer, and a heating and pressurizing treatment is performed to bond (thermally fuse) the molded body A and the molded body B via the bonding layer. When placing the molded body B, the molded body A and the molded body B may be temporarily fixed so as to be 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.

[0059] <<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.

[0060] 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 for the heating and pressurizing treatment is preferably Tg ２ +80°C or less is preferable, and Tg ２ It is more preferable that the temperature of the bonding layer is +60°C or lower. In addition, when the bonding layer contains two or more kinds of resin components, Tg ２is the weighted average glass transition temperature of the two or more resin components constituting the bonding layer. The temperature at which the heating and pressurizing treatment is performed 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 at which the heating and pressurizing treatment is performed is, for example, preferably 0.1 MPa or higher, more preferably 0.4 MPa or higher, and even more preferably 0.6 MPa or higher, and is 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 which the heating and pressurizing treatment is performed 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), the reduced pressure hot pressing conditions in step (iii), and the heat and pressure treatment conditions in step (iv).

[0061] An example of a method for manufacturing the bonded body of the present invention as described above will be described in detail with reference to FIG. 1 . First, in the bonding agent application step, a bonding agent (2) is applied to one side of a molded body A (1) by any method, specifically, by silk screening, as shown in FIG. 1( a). In this bonding agent application step, the bonding agent (2) is applied using a squeegee (3) through a screen mesh (4). The applied bonding agent (2) is then dried to obtain a bonding layer (5) disposed on one side of the molded body A (1), as shown in FIG. 1( b). The molded body A (1) thus obtained, having the bonding layer (5) on one side, is pressed to form a surface shape using a vacuum heating press apparatus, as shown in FIG. 1( c), which includes a cover-side mold (6 a) supporting a cover-side silicone mold (7 a) and a mold (6 b) supporting a silicone mold (7 b) having a concave-convex shape. In the surface shaping step, as shown in FIG. 1(c), the surface of the molded body A (1) on the bonding layer (5) side is placed in a vacuum heating press device so as to face the uneven silicone mold (7b). Then, by pressing down the cover-side silicone mold (7a), the surface of the molded body A (1) on the bonding layer (5) side is pressed against the uneven silicone mold (7b), and a three-dimensional structure is formed on the surface on the bonding layer (5) side. As shown in FIG. 1(d), the molded body A (1) that has undergone such a surface shaping step has a three-dimensional structure on the surface having the bonding layer (5). Then, the molded body A (1) that has a three-dimensional structure on the surface having the bonding layer (5) can be bonded by placing the molded body B (8) in contact with the bonding layer (5) and performing a bonding step. The bonded body (9) obtained through such a bonding step is shown in FIG. 1(e). As explained with respect to this example, according to the method for producing a bonded body of the present invention, the surface of the molded body A (1) having the bonding layer (5) is subjected to reduced pressure hot pressing to form a three-dimensional structure, whereby the obtained bonded body (9) can be one that has little residual solvent and excellent shape precision.

[0062] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. In the following description, "%" and "parts" representing amounts are based on mass unless otherwise specified. In the examples and comparative examples, various measurements and evaluations were carried out by the following methods.

[0063] <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 a 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.

[0064] <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.

[0065] <Type and content of solvent: HS gas chromatography> The full-surface bonded joint (Figure 2) 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 then 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.

[0066] <Thickness of the Bonding Layer> The thickness of the bonding layer was measured using a full-surface bonded bonded body (Figure 2). When the thickness was 0.5 μm or more, the thickness (dry film thickness) of the bonding layer 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. 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 dried molded body using a sliding microtome (Ritorome REM-710; Yamato Koki Kogyo Co., Ltd.). The obtained cross-sectional section was subjected to platinum sputtering (ion sputter E-1030; Hitachi High-Technologies Corporation), and the cross section was observed using a scanning electron microscope (S-3400N; Hitachi High-Technologies Corporation) to measure the thickness of the bonding layer.

[0067] <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), and a three-point bending jig was installed. A full-surface bonded joint 30 having a width (b) and thickness (h) bonded as shown in FIG. 2 was installed on two supports 41 of a material testing machine 40 as shown in FIG. 3 , and 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 change is determined by taking any two points on the tangent line.

[0068] <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. 4 , was placed on two supports 41 of a material testing machine 40 as shown in FIG. 5 . 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.

[0069] <Flow path shape accuracy of bonded body> A molded body having a flow path before bonding (molded body A after reduced pressure heat pressing) and the bonded body after bonding were cut perpendicular to the longitudinal direction of the flow path (cross-sectional direction of the flow path) at the same position, and the cross-sections were exposed using a microtome (Ritorome REM-710, manufactured by Yamato Koki Kogyo Co., Ltd.). The obtained cross-sectional slices were subjected to platinum sputtering (ion sputter E-1030, manufactured by Hitachi High-Technologies Corporation), and the flow path shapes were recorded using a scanning electron microscope (S-3400N, manufactured by Hitachi High-Technologies Corporation). The recorded cross-sectional shapes of the flow paths before bonding and the cross-sectional shape of the bonded body were compared, and the following criteria were used for evaluation. No difference in the shape of the flow path was observed (change in cross-sectional area was less than 10%): Grade A The corners of the flow path were deformed and rounded, but the overall shape of the flow path was maintained, and the change in cross-sectional area was 10% or more but less than 20%: Grade B The corners of the flow path were significantly deformed, the shape of the entire flow path also changed, and the change in cross-sectional area was 20% or more: Grade C Those with a grade of A or B were considered to have passed, and those with a grade of C were considered to have failed.

[0070] (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.

[0071] <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 %.

[0072] —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.

[0073] 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.

[0074] The glass transition temperature (Tg) of the resulting norbornene-based cyclic olefin polymer (COP-1) was 68°C.

[0075] -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).

[0076] <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.

[0077] <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.

[0078] <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.

[0079] <COC-1> As COC-1, a cycloolefin copolymer TOPAS 9506F (registered trademark) (manufactured by Polyplastics) (glass transition temperature Tg 65° C.) was used.

[0080] (2. Preparation of Molded Articles (Injection-Molded Plates)) As the molded articles used in Examples 1-10 and Comparative Examples 1 and 2, injection-molded plates (injection-molded plate A and 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 plate A and injection-molded plate B were prepared for preparing a full-surface bonded joint and for measuring bonding strength, respectively. In Examples 1-6, 8-10, and Comparative Examples 1 and 2, injection-molded plate A and injection-molded plate B were prepared using the same type of resin. When COP (COP-2 or COP-3) was used as the resin, resin pellets were dried at a temperature of Tg-20° C. for 5 hours and used as the resin for molding.

[0081] (3. Formation of Bonding Layer) <Preparation of Bonding Agent> The bonding agents used in Examples 1 to 10 and Comparative Examples 1 and 2 were prepared as follows. The solvent and resin (COP or COC) pellets shown in Table 1 were weighed out and placed in a sealed container. 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).

[0082] <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.

[0083] - 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.

[0084] - 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.

[0085] -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.

[0086] <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).

[0087] (4. Decompression Heat Press) An acrylic plate having a channel shape on one side and the same size as the injection-molded plate (flat plate with a thickness of 2 mm x width of 25 mm x length of 75 mm) was fixed to an acrylic frame mold with the shaped surface facing up. Shin-Etsu Chemical Co., Ltd. mold-making silicone KE-1310ST as the base agent and CAT-1310 as the curing agent were mixed so that the base agent and curing agent were mixed in a ratio of 10:1, degassed, poured into the mold, covered with an aluminum frame mold, and subjected to primary curing at 80 ° C for 1 hour. After primary curing, the acrylic frame mold and the acrylic plate of the same size as the injection-molded plate were removed, and a secondary curing treatment was performed at 200 ° C for 3 hours to create a silicone mold with a channel shape fixed to the aluminum frame. Similarly, an aluminum-framed silicone mold was created on the lid side of the mold. The silicone on the lid side of the mold was flat. A 1 mm diameter hole was drilled on the side of the aluminum-framed silicone mold on the lid side of the mold for vacuum evacuation. After drying and providing the bonding layer, the injection-molded plate A used in Example 1-10 was placed in this mold, and the temperature was raised using a heat press device (manufactured by Mikado Technos, VS30-3030) while evacuating to a vacuum. After reaching 220 ° C. and 80 Pa, the plate was held for 2 minutes. After holding, a reduced-pressure heat press was performed at 220 ° C. for 8 minutes while applying a pressure of 5 MPa. At this time, the surface of the injection-molded plate A having the bonding layer was placed facing the shaping surface of the silicone mold, and a reduced-pressure heat press was performed, and a surface shaping of a flow channel shape was performed on the surface. After pressing, the mold was removed and cooled to room temperature, and the surface-shaped injection-molded plate A was removed. The above reduced-pressure heat press operation was not performed on the injection-molded plate A used in Comparative Examples 1 and 2.

[0088] (5. Preparation of bonded body test pieces by bonding molded bodies (injection-molded plates) together) For Examples 1-10, injection-molded plate B was bonded to injection-molded plate A after the formation of the bonding layer and the reduced-pressure hot pressing, and for Comparative Examples 1 and 2, injection-molded plate B was bonded to injection-molded plate A after the formation of the bonding layer, to prepare bonded body test pieces in which injection-molded plate A and injection-molded plate B were bonded via the bonding layer. As bonded body test pieces, a full-surface bonded bonded body (FIG. 2) and a bonded body for measuring bond strength (FIG. 4) were prepared. Bonding was performed by autoclave (air heating and pressurization) treatment or vacuum laminator treatment.

[0089] <Bonding autoclave (heated and pressurized air) treatment> For the full-surface bonded bonded body (Fig. 2), an injection-molded plate A with a bonding layer formed on the entire coated surface and an injection-molded plate B without a bonding agent were stacked and temporarily fixed in a direction in which they contacted 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 (Fig. 4), an injection-molded plate A with a bonding layer formed on the overlapping margin of the coated surface and an injection-molded plate B without a bonding agent were stacked and temporarily fixed in a direction in which they contacted via the bonding layer at a position where the injection-molded plates overlapped at the overlapping margin, to obtain a temporarily bonded bonded body.

[0090] The temporarily bonded bonded body was vacuum-packaged using a vacuum packaging machine (T100 manufactured by Nippon Packaging Machinery) with retort packaging material. This vacuum-packed body was placed in an autoclave (Tandelion DL-2010 manufactured by Hanyuda Iron Works), and heated and pressurized at a temperature of 120 ° C, a pressure of 0.8 MPa, and a pressure time of 30 minutes. The injection-molded plate A and the injection-molded plate B were bonded via a bonding layer to form a bonded body test piece. After completion of the autoclave, the bonded body (full-surface bonded bonded body or bonded body for bonding strength measurement) was removed after cooling to room temperature. In the obtained bonded body, a bonding layer is interposed between the three-dimensional structure surface provided on one molded body and the other molded body. And, as described above, this bonding layer is possessed by the three-dimensional structure surface of one molded body. The presence of a bonding layer on the three-dimensional structure surface of one molded body means that after heat and pressure bonding, the bonding layer melts and melts with the molded body, making the interface unclear and difficult to observe with a scanning electron microscope. In this case, when a cross section of the bonded body is obtained and observed at a magnification of 500 to 1000 times using a digital microscope (VHX-S770, manufactured by Keyence Corporation), it can be confirmed that the refractive index at the interface between the resin forming the surface of the three-dimensional structure and the resin forming the bonding layer is different.

[0091] <Vacuum laminator treatment> The temporarily bonded bonded body was placed on the hot plate of a vacuum laminator (PVL0202S, manufactured by Nisshinbo Mechatronics) heated to 120°C and covered with a Teflon (registered trademark) sheet. The chamber was closed and evacuated for 5 minutes, and then heated and pressurized at 0.1 MPa for 20 minutes. In this way, injection-molded plate A and injection-molded plate B were bonded via the bonding layer to form a bonded body test piece. After vacuum lamination, the bonded body (full-surface bonded bonded body or bonded body for bond strength measurement) was cooled to room temperature and removed.

[0092] As shown in Figure 2, the full-surface bonded joint 30 was a joint in which injection-molded plates A (21) and B (21) were bonded together at a position where the injection-molded plates overlapped on their entire surfaces via a bonding layer 13. As shown in Figure 4, the joint 20 for measuring bonding strength was a joint in which injection-molded plates A (21) and B (21) were bonded together 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.

[0093] <<Sterilization autoclave treatment: moist heat and pressure autoclave>> The full-surface bonded assembly sample was placed against a 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.

[0094] <Various measurements and evaluations> The solvent content relative to the bonded body, the shape accuracy of the bonded body, and the flexural modulus were measured using a full-surface bonded bonded body (Figure 2). The bond strength was measured using a bonded body for bond strength measurement (Figure 4). The results are shown in Table 1.

[0095]

[0096] From Table 1, it can be seen that Examples 1-10, which are joined bodies formed by joining a plurality of molded bodies made of a thermoplastic resin with a bonding layer, have a three-dimensional structure on one side of the plurality of molded bodies, and the three-dimensional structure has a bonding layer on the surface, and the bonding layer contains at least one type of cyclic olefin polymer and a solvent having a boiling point of 70 ° C. or more and 150 ° C. or less, and the solvent is contained in a proportion of less than 100 ppm by mass relative to the total mass of the joined body, have excellent shape precision of the joined body compared to Comparative Examples 1 and 2, in which the solvent content is 100 ppm by mass or more. Furthermore, when Example 1 is compared with Comparative Example 1, and Example 6 is compared with Comparative Example 2, it can be seen that by performing a reduced pressure hot press in the production of the joined body, the content of the solvent in the joined body is reduced, and the joined body has excellent shape precision.

[0097] According to the present invention, it is possible to provide a bonded body having a small amount of residual solvent and excellent shape precision, and a method for producing the same.

[0098] REFERENCE SIGNS LIST 1 Molded body A 2 Bonding agent 3 Squeegee 4 Screen mesh 5 Bonding layer 6a Lid-side mold 6b Mold 7a Lid-side silicone mold 7b Silicone mold 8 Molded body B 9 Bonded body 13 Bonding layer 20 Bonded body for measuring bonding strength 21 Injection-molded plate 22 Overlapping margin 30 Full-surface bonded bonded body 40 Material testing machine 41 Fulcrum 42 Pressing jig

Claims

1. A bonded body formed by bonding a plurality of molded bodies made of a thermoplastic resin with a bonding layer, wherein at least one of the plurality of molded bodies has a three-dimensional structure on at least one side, and the three-dimensional structure has the bonding layer on a surface thereof, and the bonding layer contains at least one type of cyclic olefin polymer and a solvent having a boiling point of 70°C or higher and 150°C or lower, and the bonded body contains the solvent having a boiling point of 70°C or higher and 150°C or lower in an amount of less than 100 ppm by mass relative to the total mass of the bonded body.

2. The joined body according to claim 1, wherein the three-dimensional structure of the molded body is a recess or a through-hole.

3. The joined body according to claim 1, wherein the at least one kind of cyclic olefin polymer contained in the joining layer is a hydrogenated product of at least one kind of cyclic olefin polymer.

4. The joined body according to claim 3, wherein the at least one hydrogenated cyclic olefin polymer contained in the joining layer is a hydrogenated ring-opening polymer of a norbornene-based monomer.

5. The bonded body according to claim 1, wherein the thickness of the bonding layer is 0.05 μm or more and 5 μm or less.

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

7. The conjugate according to any one of claims 1 to 6, wherein the solvent includes at least one of cyclohexane, methylcyclohexane, ethylcyclohexane, xylene, and toluene.

8. A method for producing a bonded body, comprising the steps of: applying a bonding agent containing at least one type of cyclic olefin polymer and a solvent having a boiling point of 70°C or more and 150°C or less to at least one surface of molded body A, which is at least one molded body among a plurality of molded bodies made from a thermoplastic resin; drying the applied bonding agent to form a bonding layer on the at least one surface of molded body A; vacuum-heat-pressing molded body A at a temperature at least 20°C higher than the glass transition temperature of the thermoplastic resin constituting molded body A to form a three-dimensional structure on the surface of molded body A having the bonding layer; and arranging molded body B, which is another molded body different from molded body A among the plurality of molded bodies, so that it is in contact with the bonding layer, and performing a heat-pressure treatment to bond molded body A and molded body B via the bonding layer to obtain a bonded body.

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