JP2020146980A - Laminate with peel resistance having non-adhesive surface - Google Patents

Abstract

To provide a laminate with peel resistance having a non-adhesive surface with which functions based on the non-adhesive surface can be exhibited for a long time by preventing peeling off of a surface layer comprising polytetrafluoroethylene (PTFE) even when applied in a high temperature environment, and a production method of the same.SOLUTION: A laminate with peel resistance having a non-adhesive surface is configured such that a surface layer comprising polytetrafluoroethylene (PTFE) is formed on a surface of a metal substrate via first and second primer layers, and is a press-bonded article of the laminate of: the metal substrate; the first primer layer constituted of a film including a polyimide resin and formed on a surface of the metal substrate; the second primer layer constituted of a melt-molded sheet including an adhesive fluorine-containing polymer and formed on a surface of the first primer layer; and a surface layer constituted of a calcined sheet including PTFE and formed on a surface of the second primer layer.SELECTED DRAWING: None

Description

The present invention relates to a peel-resistant laminate having a non-adhesive surface, and is applied to a surface in contact with raw materials such as a hopper for industrial machinery and a fryer for food processing. It relates to a laminate.

For example, when transporting raw materials, various types of hoppers, chutes, buckets, containers, etc. (hereinafter, may be referred to as "hoppers, etc.") provided in the transport machine may adhere to their surfaces. Raw materials and the like may adhere to the surface of the hopper and the like as the raw materials and the like are put in and the transportation operation is repeated. When such raw materials and the like adhere to the hopper and the chute, it becomes difficult for the raw materials and the like to be discharged from the discharge port of the hopper, and it may be necessary to forcibly send out the raw materials and the like by a machine or the like. If raw materials or the like adhere to the bucket, the raw materials or the like are deposited, which may reduce the work efficiency. Further, even in a fryer for food processing and a rice cooker, when cooking is performed, raw materials and the like may adhere to the surface thereof, resulting in a decrease in thermal efficiency and a decrease in work efficiency due to time required for cleaning and the like.

As a measure for improving these, it has been proposed to provide a layer of a fluororesin on the surface of a member in contact with raw materials such as a hopper (Patent Document 1). Further, conventionally, various techniques for providing a fluorine-based resin layer on the surface of a metal base material have been proposed (Patent Documents 2 to 4).

Patent Document 1 describes a hopper for a rice cake making machine in which a deep-drawing molded container made of tetrafluorinated ethylene resin that fits the main body is attached to the inner surface of the hopper main body for the rice cake making machine with a silicone adhesive. .. With such a configuration, it is said that an inexpensive hopper for a rice cake making machine can be provided, which has excellent wear resistance and non-adhesiveness.

In Patent Document 2, a layer composed of at least one of a polyamide-imide resin and a polyimide resin is provided as a first layer, a fluororesin primer layer is provided as a second layer, and a fluororesin topcoat layer is provided as a third layer on the surface of the base material. It is stated that it applies to this order. With such a configuration, it is said that strong adhesion between each layer between the base material and the fluororesin can be obtained, and a fluororesin coating showing excellent properties of the fluororesin coating and good hardness at high temperature can be obtained. ing.

Patent Document 3 describes a fluoropolymer comprising a base material, a primer layer formed on the base material, and a molded product layer formed on the primer layer, wherein the base material is the primer. The surface forming the layer is made of a heat-resistant rubber, a heat-resistant resin or a metal, the primer layer is made of a functional group-containing fluoroethylene polymer, and the molded product layer is a fluororesin. Described is a fluoropolymer-containing laminate characterized by being formed of a fluororesin-molded article made of. With such a configuration, it is said that the adhesiveness is good even if the etching process is not performed.

Patent Document 4 describes a sliding member that is used in an oil-lubricated environment and has a sliding layer on the surface of the iron-based metal base material, and the sliding layer is heat-resistant to the surface of the iron-based metal base material. A base layer containing a sex resin and a first fluororesin and a second fluororesin layer on the surface of the base layer are provided, and the heat-resistant resin has at least oxygen atoms, nitrogen atoms and sulfur atoms together with carbon atoms. A resin containing one atom in at least the main chain of the polymer structure, and the second fluororesin layer is a crosslinked fluororesin layer in which at least the vicinity of the surface of the sliding layer is crosslinked. The moving members are described. It is said that such a configuration can suppress wear even under conditions of high sliding speed and high surface pressure in lubricating oil, and can maintain the life of sliding parts and bearings for a long period of time.

Special Publication No. 63-22865 Japanese Unexamined Patent Publication No. 53-75283 International Publication No. 2004/018201 JP-A-2017-32141

In the invention described in Patent Document 1, since a deep-drawn molded container made of tetrafluorinated ethylene resin is attached using a silicone adhesive, when it is applied to a hopper or the like other than for a rice cake making machine, it is in terms of durability. Not always enough. For example, when applied to applications that are used for a long time in a high temperature environment, such as hoppers installed in devices that transport high temperature slag and sludge generated in steelworks, food processing fryer, rice cookers, etc. Easily peeled off at the part of the adhesive used for dressing.

By applying the inventions described in Patent Documents 2 to 4 to such applications, the durability may be improved to some extent, but when applied to the applications used for a long time in a high temperature environment as described above. , There is room for improvement for the following reasons.

In the invention described in Patent Document 2, when the primer layer of the second layer is formed, a dispersion liquid in which a fluororesin and a binder substance having adhesion between the first layer and the third layer are dispersed in a liquid medium is sprayed. And so on, and perform a dry firing process. Further, when the fluororesin topcoat layer of the third layer is formed, the fluororesin powder or the dispersion liquid of the fluororesin particles is applied by spraying or the like, and the drying and firing treatment is performed. As described above, when the dispersion liquid is used when forming the second and third layers, the density of the coating film is lowered, so that the number of bonding points between the layers is small, and the bonding strength and durability are not sufficient. Even in the invention described in Patent Document 3, since the dispersion liquid of the functional group-containing fluoroethylene polymer is applied to the formation of the primer layer, the bonding strength and durability are not sufficient. In the invention described in Patent Document 4, the base layer is a mixture of a heat-resistant resin and a fluororesin, and a dispersion liquid of these resins is applied to form the base layer in the same manner as in Patent Documents 2 and 3. Therefore, the joint strength and durability are not sufficient.

Therefore, an object of the present invention is to prevent peeling of a surface layer containing polytetrafluoroethylene (PTFE) even when applied in a high temperature environment, and to exhibit a function based on a non-adhesive surface for a long period of time. It is an object of the present invention to provide a peel-resistant laminate having a non-adhesive surface and a method for producing the same.

The present inventor has diligently studied to solve the above-mentioned problems. As a result, a film containing a polyimide resin, a melt-molded sheet containing an adhesive fluorine-containing polymer, and a fired sheet containing polytetrafluoroethylene are sequentially laminated on the surface of the metal base material, and the laminated body is pressure-bonded and pressure-bonded. It was found that the above-mentioned problems can be solved by making things.

The first aspect of the present invention is a peel-resistant laminate having a non-adhesive surface in which a surface layer containing polytetrafluoroethylene (PTFE) is formed on the surface of a metal base material via first and second primer layers. It contains a metal base material, a first primer layer composed of a film containing a polyimide resin formed on the surface of the metal base material, and an adhesive fluorine-containing polymer formed on the surface of the first primer layer. The present invention relates to a peel-resistant laminate, which is a pressure-bonded product of a second primer layer composed of a melt-molded sheet and a laminate of surface layers composed of a fired sheet containing PTFE formed on the surface of the second primer layer. ..

In the embodiment of the present invention, the film constituting the first primer layer may be a sintered body of a liquid coating film containing a polyimide precursor or a sintered sheet of a polyimide resin.

In the embodiment of the present invention, the adhesive fluorine-containing polymer may have a carbonyl group and a melting point of 220 to 320 ° C.

In the embodiment of the present invention, the metal base material may be a flat plate made of stainless steel or carbon steel.

In the embodiment of the present invention, the peel strength of the surface layer may be 3 N / mm or more.

In the embodiment of the present invention, the thickness of the surface layer may be 0.1 to 5 mm.

The second aspect of the present invention is a peel-resistant laminate having a non-adhesive surface in which a surface layer containing polytetrafluoroethylene (PTFE) is formed on the surface of a metal base material via first and second primer layers. In the manufacturing method, a first primer layer installation step of forming a film containing a polyimide resin on the surface of a metal base material, and a melt-molded sheet containing an adhesive fluoropolymer on the surface of a film containing a polyimide resin are installed. Second primer layer installation step, surface layer installation step of installing a PTFE fired sheet on the surface of a melt-molded sheet containing an adhesive fluoropolymer, first and second primer layers, surface layer on the surface of a metal substrate. The present invention relates to a method for producing a peel-resistant laminate, which comprises a crimping step of heating and compressing the laminate in which is installed.

In the embodiment of the present invention, crimping may be performed under the conditions of a heating temperature of 340 to 380 ° C., a pressure of 1 to 5 MPa, and a pressurizing time of 5 to 10 minutes in the crimping step.

According to the present invention, even when applied in a high temperature environment, it is possible to prevent peeling of the surface layer containing polytetrafluoroethylene (PTFE) and exhibit a function based on a non-adhesive surface for a long period of time. It is possible to provide a peel-resistant laminate having a non-adhesive surface and a method for producing the same.

It is explanatory drawing for demonstrating the manufacturing method of the test piece in Example 1. FIG.

Hereinafter, embodiments of the present invention will be described.

The peel-resistant laminate having a non-adhesive surface (hereinafter, may be simply referred to as “peeling-resistant laminate”) according to the embodiment of the present invention includes a metal base material, a first primer layer, and a second layer. It is a pressure-bonded product of a laminated body in which a primer layer and a surface layer are laminated in this order. The first primer layer is composed of a film containing a polyimide resin formed on the surface of a metal base material. The second primer layer is composed of a melt-molded sheet containing an adhesive fluorine-containing polymer. The surface layer is composed of a calcined sheet containing polytetrafluoroethylene (hereinafter referred to as "PTFE").

As described above, by adopting a specific molded product as the second primer layer and the surface layer containing the fluorine-based polymer, each layer is denser than the case where the fired product of the coating film using the dispersion liquid is adopted. Can have a molecular structure. Therefore, it is possible to increase the number of junctions between the first primer layer and the second primer layer and between the second primer layer and the surface layer. Then, by crimping these specific molded products, excellent bonding strength is imparted, and excellent peeling resistance is imparted even in long-term use in a high temperature environment.

The fired sheet containing PTFE (hereinafter, may be referred to as "PTFE sheet") constituting the surface layer is formed by using PTFE as a resin component.

PTFE shows excellent chemical resistance, does not dissolve or swell in almost all chemicals, and exhibits excellent stability only by being attacked by molten metallic sodium or high-temperature and high-concentration fluorine gas. Further, it has excellent heat resistance, has a melting point of about 327 ° C., and has a continuous use temperature of about 260 ° C., which is extremely high among organic materials, and its mechanical strength hardly decreases even if it is left at 250 ° C. for a long time. In addition, its surface properties show excellent hydrophobicity, oleophobicity and non-adhesiveness.

As described above, PTFE is excellent in chemical resistance and heat resistance, and has high hydrophobicity, oleophobicity, and non-adhesiveness. Therefore, the PTFE sheet can be used as a raw material in applications such as hoppers and food processing fryer. By being provided on the contacting surface, the PTFE sheet becomes a sliding surface, the slidability of raw materials, etc. is improved, and the deposits on the sliding surface fall before they grow significantly to the sliding surface. Adhesion and residue can be suppressed. Alternatively, even if it adheres, it can be easily removed.

The PTFE sheet is preformed into a sheet shape. Since PTFE only gels even when heated and does not show fluidity, general injection molding or extrusion molding is not easy. Therefore, for example, it is molded by a sintering method or a paste extrusion method. As these methods, known methods can be adopted. In the sintering method, for example, PTFE powder is put into a mold, pressurized, and fired at a temperature equal to or higher than the melting point of PTFE. If necessary, when the whole becomes a transparent gel, it may be immediately transferred to another mold for secondary molding. Further, after molding, machining may be performed so as to obtain a desired shape. In the paste extrusion method, an organic solvent or the like is added to the PTFE powder to form a paste, which is formed into a sheet by a calendar, and then the solvent is volatilized before firing. Examples of the method other than the sintering method and the paste extrusion method include a method of cutting a columnar or prismatic molded body obtained by the above-mentioned firing method or the paste extrusion method into a sheet. Of these, from the viewpoint of the smoothness of the PTFE sheet, the method of cutting the above-mentioned molded body into a sheet is preferable.

The thickness of the PTFE sheet can be set in consideration of the application. From the viewpoint of continuously obtaining various effects such as abrasion resistance and durability by the above-mentioned PTFE, 0.1 to 5 mm is preferable, and 0.3 to 5 mm is more preferable.

The resin component of the PTFE sheet is PTFE, but other additives may be added in addition to the resin component. Examples of the additive include a colorant, a reinforcing material, a lubricity imparting material, an abrasion resistance imparting material, and the like.

The material constituting the metal base material can be appropriately selected depending on the intended use and the like. Examples of such a material include iron, aluminum, copper, gold, and silver. The iron may be an alloy containing iron as a main component containing carbon having a content of 2.0% or less, and examples thereof include carbon steel and alloy steel. Examples of the alloy steel include stainless steel and chrome molybdenum steel. Of these, stainless steel, aluminum, and carbon steel are preferable, and stainless steel and carbon steel are more preferable, from the viewpoint of corrosion resistance, weight, and versatility. Further, in the case of carbon steel, the surface of the base material may be plated. Examples thereof include galvanized steel sheet (registered trademark), which is a steel sheet treated by aluminum-zinc alloy plating, and galvanized steel sheet treated by galvanizing.

The shape of the metal base material can be appropriately selected depending on the application and the like. For example, flat plates, curved plates, bent plates, squeezed plates and the like can be mentioned. Of these, a flat plate is preferable in consideration of the elastic deformation limit of the PTFE sheet and the installation location of the peel-resistant laminate. When the metal base material is, for example, plate-shaped, its thickness can be set in consideration of each application and constituent material. For example, when the peel-resistant laminate is used by bending or the like, the thickness can be determined according to the characteristics of the constituent materials of the metal base material and the form of the installation location of the peel-resistant laminate, for example, 0. It can be 1 to 5 mm.

The metal base material may be formed with a fixing portion for fixing the peel-resistant laminate to the surface of a member constituting, for example, a hopper or the like. Since the fixing portion is formed, the peel-resistant laminate can be easily fixed to the hopper or the like in a short time without coating treatment or the like. Therefore, for example, a non-adhesive surface can be easily formed in a short time on an existing machine provided with a hopper or the like. That is, for example, a hopper or the like is often a relatively large member, so it is difficult to carry it. However, by adopting the above configuration, it is easy to use anywhere without using a large-scale coating facility. It can be installed in a short time. Such fixing portions include, for example, a through hole for fixing a member such as a hopper with a bolt nut or a rivet, a female screw hole screwed with a male screw, and a clip for holding a predetermined part such as a hopper. , A protrusion receiver that engages with and locks a protrusion provided in a predetermined part such as a hopper, a fitting structure that fits and fixes in a recess provided in a predetermined part such as a hopper, or fixed to a metal base material. Permanent magnets, electromagnets or magnetic materials (these are selected depending on whether the various members and the base sheet are magnetic materials, and the various members and the peel-resistant laminate are fixed by the interaction between the magnet and the magnetic material. ) Etc. are used in physical coupling. Such fixing portions may be provided at one location or two or more locations depending on the intended use. The installation position of the fixed portion can also be determined according to the application and the like. Further, these various fixing portions may be adopted in combination.

Although the fixing portion may be provided on the metal base material in this way, the peel-resistant laminate may be fixed to a hopper or the like by welding. In this case, it is preferable to select the shape of the peel-resistant laminate in consideration of the fixing portion and control the output of the welding apparatus so that the PTFE sheet is not overheated. In this way, the welded portion (welded surface) of the peel-resistant laminate may be used as the joint portion.

As the film containing the polyimide resin constituting the first primer layer, a conventionally known film of a polyimide resin can be adopted.

The polyimide resin may be either a thermosetting polyimide or a thermoplastic polyimide, but from the viewpoint of heat resistance, the thermosetting polyimide is preferable. The thermosetting polyimide may be either a condensation type polyimide or an addition type polyimide, but from the viewpoint of heat resistance, the condensation type polyimide is preferable.

In the condensed polyimide, for example, an aromatic polyvalent carboxylic acid component and a diamine component are reacted to produce a polyamic acid which is a polyimide precursor, and a dehydration and imidization (cyclization) reaction is carried out by heating or using an imidizing agent. It is obtained by letting and curing.

Examples of the aromatic polyvalent carboxylic acid component include pyromellitic acid, 3,3', 4,4'-benzophenone tetracarboxylic acid, oxydiphthalic acid, 2,3,6,7-naphthalenedicarboxylic acid, 2,2-. Examples thereof include bis (3,4-dicarboxyphenyl) ether, pyridine-2,3,5,6-tetracarboxylic acid and acid anhydrides thereof. These aromatic polyvalent carboxylic acid components may be used alone or in combination of two or more.

Examples of the diamine component include paraphenylenediamine, metaphenylenediamine, benzene, paraxylylene diamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, and 1,4-. Bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 2,2-bis (4-aminophenoxyphenyl) propane, bis [4- (4-Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-) Aminophenoxy) Biphenyl and the like can be mentioned. These diamine components may be used alone or in combination of two or more.

The film containing the polyimide resin may be, for example, a sintered body of a liquid coating film containing a polyamic acid which is a polyimide precursor, a sintered sheet of the polyimide resin, a melt-molded sheet of the thermoplastic polyimide resin, or the like. Of these, from the viewpoint of heat resistance, a sintered body of a liquid coating film containing a polyamic acid which is a polyimide precursor and a sintered sheet of a polyimide resin are preferable. The polyimide resin film is formed by, for example, casting a liquid containing a polyamic acid obtained by reacting the above-mentioned aromatic polyvalent carboxylic acid component and a diamine component in an organic solvent on a support to promote imidization. Obtainable.

Examples of the solvent used for producing polyamic acid include N, N-dimethylacetamide, N, N-dimethylformamide, N, N-diethylacetamide, N, N-dimethoxyacetamide, N-methyl-2-pyrrolidone, and the like. 1,3-Dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis2- ( 2-methoxyethoxy) ethyl ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyridine, picolin, dimethylsulfoxide, dimethylsulfone, tetramethylurea, hexamethylphosphoramide, phenol, o-cresol, m- Examples thereof include cresol, p-cresol, m-cresol acid, p-chlorophenol, anisole, benzene and toluenesilene. These organic solvents may be used alone or in admixture of two or more.

The liquid containing the polyamic acid may be prepared according to a conventional method using, for example, each of the above-mentioned components and an organic solvent, or a commercially available liquid may be used. Examples of commercially available products include U-varnish manufactured by Ube Industries, Ltd.

The sintered body of the coating film of the liquid containing polyamic acid, which is a polyimide precursor, forms a coating film by drying the liquid containing polyamic acid applied to the surface of the metal substrate, and the coating film is fired to obtain polyamic acid. Can be formed directly on the surface of the metal substrate by imidizing.

For the polyimide resin sintered sheet, a liquid containing polyamic acid is applied to a resin film such as a polyester film and dried to prepare a self-supporting coating film, and this coating film is peeled from the resin film to form a metal frame. It can be produced by fixing and firing. By installing this sintered sheet on the surface of a metal base material, a film containing a polyimide resin can be formed on the surface of the metal base material.

The thickness of the film containing the polyimide resin can be, for example, 0.005 to 1 mm.

The melt-molded sheet containing the adhesive fluorinated polymer constituting the second primer layer is obtained by melting the adhesive fluorinated polymer and molding it into a sheet. As such a melt-moldable adhesive fluorine-containing polymer, an adhesive fluorine-containing copolymer can be exemplified. The adhesive fluorine-containing copolymer preferably contains a carbonyl group, and examples thereof include those described in Japanese Patent No. 4424246, Japanese Patent No. 5365939, and Japanese Patent No. 5263269. These adhesive fluorine-containing copolymers are shown below.

The adhesive fluorine-containing copolymer has a repeating unit (a) based on tetrafluoroethylene (hereinafter referred to as TFE) and / or chlorotrifluoroethylene (hereinafter referred to as CTFE), a dicarboxylic acid anhydride group, and has. To the repeating unit (b) and other monomers based on the cyclic hydrocarbon monomer having a polymerizable unsaturated group in the ring (however, if it overlaps with the repeating units (a) and (b), the monomer is excluded). Contains the based repeating unit (c).

In the adhesive fluorine-containing copolymer, the repeating unit (a) is 50 to 99.89 mol% with respect to the total molar amount of the repeating unit (a), the repeating unit (b) and the repeating unit (c). The repeating unit (b) is 0.01 to 5 mol%, and the repeating unit (c) is 0.1 to 49.99 mol%. The repeating unit (a) is preferably 50 to 99.47 mol%, the repeating unit (b) is 0.03 to 3 mol%, and the repeating unit (c) is 0.5 to 49.97 mol%, more preferably. The repeating unit (a) is 50 to 98.95 mol%, the repeating unit (b) is 0.05 to 2 mol%, and the repeating unit (c) is 1 to 49.95 mol%. When the molar% of the repeating unit (a), the repeating unit (b) and the repeating unit (c) is in this range, the adhesive fluorine-containing copolymer is excellent in heat resistance and chemical resistance. Further, when the molar% of the repeating unit (b) is in this range, the adhesive fluorine-containing copolymer is a base material sheet and a PTFE sheet of a constituent material such as a thermoplastic resin other than the adhesive fluorine-containing copolymer. Excellent adhesion to. When the molar% of the repeating unit (c) is in this range, the adhesive fluorine-containing copolymer is excellent in moldability and mechanical properties such as stress crack resistance.

The above-mentioned "cyclic hydrocarbon monomer having a dicarboxylic acid anhydride group and having a polymerizable unsaturated group in the ring" (hereinafter, simply abbreviated as cyclic hydrocarbon monomer) has one or more 5-membered rings or 6 A cyclic hydrocarbon composed of a member ring, and a polymerizable compound having a dicarboxylic acid anhydride group and an intracyclically polymerizable unsaturated group. As the cyclic hydrocarbon, a cyclic hydrocarbon having one or more bridged polycyclic hydrocarbons is preferable. That is, a cyclic hydrocarbon composed of an Arihashi polycyclic hydrocarbon, a cyclic hydrocarbon obtained by condensing two or more of the Arihashi polycyclic hydrocarbons, or a cyclic hydrocarbon obtained by condensing an Arihashi polycyclic hydrocarbon with another cyclic hydrocarbon. It is preferable to have. Further, this cyclic hydrocarbon monomer has one or more in-ring polymerizable unsaturated groups, that is, polymerizable unsaturated groups existing between carbon atoms constituting the hydrocarbon ring. This cyclic hydrocarbon monomer further has a dicarboxylic acid anhydride group (-CO-O-CO-), and the dicarboxylic acid anhydride group may be bonded to two carbon atoms constituting the hydrocarbon ring, and the ring may be bonded. It may be bonded to two outer carbon atoms. Preferably, the dicarboxylic acid anhydride group is a carbon atom constituting the ring of the cyclic hydrocarbon and is bonded to two adjacent carbon atoms. Further, a halogen atom, an alkyl group, an alkyl halide group, or another substituent may be bonded to the carbon atom constituting the ring of the cyclic hydrocarbon instead of the hydrogen atom.

Specific examples thereof are those represented by the formulas (1) to (8). Here, R in the formulas (2) and (5) to (8) is a halogen atom selected from a lower alkyl group having 1 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and the lower grade. Indicates an alkyl halide group in which a hydrogen atom in the alkyl group is replaced with a halogen atom.

The cyclic hydrocarbon monomer is preferably represented by the formula (1), 5-norbornene-2,3-dicarboxylic acid anhydride (hereinafter referred to as NAH), the formulas (3) and (4). Cyclic hydrocarbon monomers that are acid anhydrides, and cyclic hydrocarbon monomers whose substituent R is a methyl group in formulas (2) and (5) to (8). More preferably, it is NAH.

Examples of other monomers include vinyl fluoride, vinylidene fluoride (hereinafter referred to as VdF), CTFE (excluding the case where it is used as the repeating unit (a)), trifluoroethylene, hexafluoropropylene (hereinafter referred to as VdF). HFP), CF ₂ = CFOR ^f1 (where R ^f1 is a perfluoroalkyl group having 1 to 10 carbon atoms and may contain oxygen atoms between carbon atoms), CF ₂ = CFOR ^f2 SO ₂ X ¹ (R) ^f2 is a perfluoroalkylene group having 1 to 10 carbon atoms and may contain an oxygen atom between carbon atoms, X ¹ is a halogen atom or a hydroxyl group), CF ₂ = CFOR ^f2 CO ₂ X ² (where R ^f2 is the above-mentioned Same, X ² is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.), CF ₂ = CF (CF ₂ ) _p OCF = CF ₂ (where p is 1 or 2), CH ₂ = CX ³ (where p is 1 or 2) CF ₂ ) _q X ⁴ (where X ³ and X ⁴ are hydrogen or fluorine atoms independently of each other, q is an integer of 2 to 10), perfluoro (2-methylene-4-methyl-1,3-). Dioxolane), olefins having 2 to 4 carbon atoms such as ethylene, propylene and isobutene, vinyl esters such as vinyl acetate, vinyl ethers such as ethyl vinyl ether and cyclohexyl vinyl ether, and the like can be mentioned. The other monomers may be used alone or in combination of two or more.

Specific examples of CF ₂ = CFO R ^f1 include, for example, CF ₂ = CFOCF ₂ CF ₃ , CF ₂ = CFOCF ₂ CF ₂ CF ₃ , CF ₂ = CFOCF ₂ CF ₂ CF ₂ CF ₃ , CF ₂ = CFO (CF _2). ) ₈ F, and the like. Preferably, CF ₂ = CFOCF ₂ CF ₂ CF ₃ .

Specific examples of CH ₂ = CX ³ (CF ₂ ) _q X ⁴ include, for example, CH ₂ = CH (CF ₂ ) ₂ F, CH ₂ = CH (CF ₂ ) ₃ F, CH ₂ = CH (CF ₂ ). ₄ F, CH ₂ = CF (CF ₂ ) ₃ H, CH ₂ = CF (CF ₂ ) ₄ H and the like. _{Preferably, CH 2 = CH (CF 2} ) a ₄ F or _{CH 2 = CH (CF 2)} 2 F.

Other monomers are preferably VdF, HFP, CTFE (except when used as a repeating unit (a)), CF ₂ = CFOR ^f1 , CH ₂ = CX ³ (CF ₂ ) _q X ⁴ , One or more selected from the group consisting of ethylene, propylene and vinyl acetate, more preferably HFP, CTFE (excluding the case where it is used as a repeating unit (a)), CF ₂ = CFOR ^f1 . One or more selected from the group consisting of ethylene and CH ₂ = CX ³ (CF ₂ ) _q X ⁴ . Most preferably, HFP or CF ₂ = CFOR ^f1 . Further, as CF ₂ = CFOR ^f1 , a perfluoroalkyl group having R ^f1 having 1 to 6 carbon atoms is preferable, a perfluoroalkyl group having 2 to 4 carbon atoms is more preferable, and a perfluoropropyl group is most preferable.

Specific examples of the adhesive fluoropolymer include TFE / CF ₂ = CFOCF ₂ CF ₂ CF ₃ / NAH copolymer, TFE / HFP / NAH copolymer, TFE / CF ₂ = CFOCF ₂ CF _2. CF ₃ / HFP / NAH copolymer, TFE / VdF / NAH copolymer, TFE / CH ₂ = CH (CF ₂ ) ₄ F / NAH / ethylene copolymer, TFE / CH ₂ = CH (CF ₂ ) ₂ F / NAH / ethylene copolymer, CTFE / CH ₂ = CH (CF ₂ ) ₄ F / NAH / ethylene copolymer, CTFE / CH ₂ = CH (CF ₂ ) ₂ F / NAH / ethylene copolymer, CTFE / CH ₂ = CH (CF ₂ ) ₂ F / NAH / ethylene copolymer and the like can be mentioned.

The melting point of the adhesive fluorine-containing copolymer is preferably 150 to 320 ° C., more preferably 200 to 320 ° C., further preferably 220 to 320 ° C., and particularly preferably 220 to 310 ° C. The melting point can be adjusted by appropriately selecting the content ratio of the repeating unit (a), the repeating unit (b) and the repeating unit (c) within the above range.

If the polymer terminal group of the adhesive fluorine-containing copolymer has an adhesive functional group such as an ester group, a carbonate group, a hydroxyl group, a carboxyl group, a carbonyl fluoride group, or an acid anhydride residue, the adhesive fluorine-containing copolymer is said to have an adhesive functional group. It is preferable because it has excellent adhesion to a base sheet and a PTFE sheet of a constituent material such as a thermoplastic resin other than a copolymer. The polymer terminal group having an adhesive functional group can be introduced by appropriately selecting a radical polymerization initiator, a chain transfer agent, or the like at the time of producing the adhesive fluorine-containing copolymer.

The volumetric flow velocity (hereinafter referred to as Q value) of the adhesive fluorine-containing copolymer can be 0.1 to 1000 mm ³ / sec. The Q value is an index showing the melt fluidity of the adhesive fluorine-containing copolymer and serves as a guideline for the molecular weight. A large Q value indicates a low molecular weight, and a small Q value indicates a high molecular weight. The Q value is the adhesion when extruding into an orifice with a diameter of 2.1 mm and a length of 8 mm under a load of 7 kg at a temperature 50 ° C. higher than the melting point of the adhesive fluoropolymer using a flow tester manufactured by Shimadzu Corporation. The extrusion rate of the sex-containing fluoropolymer. If the Q value is too small, extrusion molding becomes difficult, and if it is too large, the mechanical strength of the adhesive fluorine-containing copolymer decreases. Q values of the adhesive fluorocopolymer is preferably from 5 to 500 mm ³ / sec, 10 to 200 mm ³ / sec is more preferable.

The method for producing the adhesive fluorine-containing copolymer is not particularly limited, and a radical polymerization method using a radical polymerization initiator is used. As the polymerization method, bulk polymerization, solution polymerization using an organic solvent such as fluorinated hydrocarbon, chlorinated hydrocarbon, fluorinated hydrocarbon, alcohol, hydrocarbon, etc., an aqueous medium and, if necessary, an appropriate organic solvent are used. Suspension polymerization, emulsion polymerization using an aqueous medium and an emulsifier, and solution polymerization are particularly preferable.

As the radical polymerization initiator, a radical polymerization initiator having a half-life of 10 hours and a temperature of 0 ° C. to 100 ° C. is preferable. More preferably, it is 20 to 90 ° C. Specific examples thereof include azo compounds such as azobisisobutyronitrile, non-fluorinated diacyl peroxides such as isobutylyl peroxide, octanoyl peroxide, benzoyl peroxide and lauroyl peroxide, diisopropyl peroxydicarbonate and di-n-propyl. Peroxy dicarbonates such as peroxy dicarbonates, peroxy esters such as tert-butyl peroxypivalate, tert-butyl peroxyisobutyrate, and tert-butyl peroxyacetate, (Z (CF ₂ ) _r COO) ₂ (where Z is It is a hydrogen atom, a fluorine atom or a chlorine atom, and r is an integer of 1 to 10), such as a fluorine-containing diacyl peroxide, and an inorganic peroxide such as potassium persulfate, sodium persulfate, and ammonium persulfate. And so on.

When controlling the Q value of the adhesive fluorine-containing copolymer, it is also preferable to use a chain transfer agent. Examples of the chain transfer agent include alcohols such as methanol and ethanol, chlorofluorohydrocarbons such as 1,3-dichloro-1,1,2,2,3-pentafluoropropane and 1,1-dichloro-1-fluoroethane. Hydrocarbons such as pentane, hexane and cyclohexane can be mentioned. Examples of the chain transfer agent for introducing an adhesive functional group into the polymer terminal of the adhesive fluorine-containing copolymer include acetic acid, acetic anhydride, methyl acetate, ethylene glycol, propylene glycol and the like.

The polymerization conditions of the adhesive fluorine-containing copolymer are not particularly limited, and the polymerization temperature is preferably 0 to 100 ° C, more preferably 20 to 90 ° C. The polymerization pressure is preferably 0.1 to 10 MPa, more preferably 0.5 to 3 MPa. The polymerization time is preferably 1 to 30 hours.

The concentration of the cyclic hydrocarbon monomer during the polymerization is preferably 0.01 to 5 mol%, more preferably 0.1 to 3 mol%, and most preferably 0.1 to 1 mol% with respect to all the monomers. If the concentration of the cyclic hydrocarbon monomer is too high, the polymerization rate tends to decrease. Within the above range, the polymerization rate during production does not decrease, and the fluorine-containing copolymer has excellent adhesiveness. During the polymerization, as the cyclic hydrocarbon monomer is consumed in the polymerization, it is preferable to continuously or intermittently supply the consumed amount into the polymerization tank to maintain the concentration of the cyclic hydrocarbon monomer in this range.

The adhesive fluorine-containing copolymer obtained by the above-mentioned production method can be obtained in the form of pellets, powder or other forms according to a conventional method. Since this adhesive fluorine-containing copolymer is excellent in moldability, it can be injection-molded or extruded, and can be molded into a desired shape. Further, since the above-mentioned adhesive fluorine copolymer is excellent in flexibility, the sheet-shaped melt-molded product using them suppresses the peeling of the laminated sheet even if it is bent or drawn. it can.

The adhesive fluorine-containing copolymer can be produced as described above, but a commercially available product can be used. For example, EA-2000 manufactured by AGC Inc. can be mentioned.

The thickness of the melt-molded sheet can be appropriately selected depending on the type and application, but is preferably 5 to 100 μm, more preferably 25 to 100 μm, from the viewpoint of ensuring a predetermined or higher peel strength.

The peel strength between the surface layer and the metal base material is preferably 3 N / mm or more. Since the peel strength is usually higher, there is no particular upper limit. Such peel strength can be measured by, for example, a peel strength test of an adhesive tape / adhesive sheet test method. The test conditions at that time can be carried out according to JIS Z 0237. The peel strength is the value obtained by dividing the measured value by the width of the test piece.

As described above, the peel-resistant laminate includes a metal base material, a film containing a polyimide resin constituting the first primer layer, a predetermined melt-molded sheet constituting the second primer layer, and a predetermined surface layer. It is a crimped product of the laminated body of the fired sheet of. The thickness of each layer after crimping is equivalent to the thickness of each film and sheet before crimping. Therefore, the thicknesses of the first primer layer, the second primer layer, and the surface layer may be substantially the same as the thicknesses of the film containing the polyimide resin, the melt-molded sheet, and the fired sheet, respectively. Such adjustment of the thickness can be realized by appropriately selecting the crimping conditions.

The method for producing a peel-resistant laminate according to an embodiment of the present invention includes, for example, a step of installing a first primer layer for forming a film containing a polyimide resin on the surface of a metal base material, a step of installing a first primer layer on the surface of the film containing a polyimide resin. Second primer layer installation process for installing a melt-molded sheet containing an adhesive fluoropolymer, surface layer installation step for installing a PTFE fired sheet on the surface of a melt-molded sheet containing an adhesive fluoropolymer, metal base It includes a first and second primer layers and a crimping step of heating and compressing a laminate on which the surface layer is installed on the surface of the material.

By including the above steps, a peel-resistant laminate having a non-adhesive surface in which a surface layer containing PTFE is formed on the surface of a metal base material via first and second primer layers can be produced. Can be done.

In the first primer layer installation step, if necessary, the surface of the metal base material may be subjected to a cleaning treatment or a treatment for removing burrs and the like on the surface of the metal base material (devaluation treatment). .. Examples of the cleaning treatment include a treatment of removing oil with a solvent such as acetone. After cleaning as necessary, a film containing a polyimide resin is formed on the surface of the metal base material.

To form a film containing a polyimide resin, for example, a method of applying a liquid containing a polyimide precursor to the surface of a metal base material and then sintering the coating film to form a sintered film, a method of forming a preformed thermosetting film. Examples thereof include a method of installing a sintered sheet of sex polyimide or a melt-molded sheet of thermoplastic polyimide on the surface of a metal base material. Examples of the liquid containing the polyimide precursor include, as described above, a liquid containing a polyamic acid obtained by reacting an aromatic polyvalent carboxylic acid component and a diamine component in a solvent.

In the second primer layer installation step, the melt-molded sheet containing the adhesive fluoropolymer described above is placed on the surface of the film containing the polyimide resin, and in the surface layer installation step, PTFE is fired on the surface of the melt-molded sheet. Install the seat. As described above, by using the molded product as a member constituting the second primer layer and the surface layer, a layer having a dense molecular structure is formed.

In the crimping step, as described above, the laminate in which the metal base material, the first primer layer, the second primer layer, and the surface layer are laminated in this order is compressed in the stacking direction while being heated. As a result, the layers having a dense molecular structure are pressure-bonded, so that the layers are reliably bonded at the bonding points existing in many of the layers, and good peel resistance is imparted.

The processing conditions in the crimping process can be appropriately determined. For example, the heating temperature is preferably pressurized at a temperature equal to or higher than the melting point of PTFE, more preferably 340 to 380 ° C. The actual pressure is preferably 1 to 5 MPa. The pressurization time is preferably 5 to 10 minutes. As described above, when heat-bonding is performed at a temperature equal to or higher than the melting point of PTFE, the peeling resistance at high temperatures can be dramatically improved by providing the polyimide resin sintered film.

By fixing the peel-resistant laminate obtained as described above to the surface of a member constituting the hopper or the like, the surface of the hopper or the like can be used for a long period of time in a high-temperature environment and is non-adhesive. A sex surface can be imparted.

Hereinafter, embodiments of the present invention will be described in more detail by way of examples with reference to the drawings as necessary.

(Peeling test)
The test pieces of the laminates obtained in Examples and Comparative Examples were allowed to stand in a hot air circulation furnace (FHH-201M, manufactured by ESPEC CORPORATION) at 200 ° C. for 1, 2 or 4 weeks, and then a tensile tester ( The peel strength was measured using an autograph AG-X plus, load capacity: 20 kN) manufactured by Shimadzu Corporation. The test conditions were a tensile speed of 30 mm / min and an average value of 5 times as the peel strength (N / mm). The results are shown in Table 1.

(Manufacturing Example 1)
A melt-molded sheet of size: 500 mm x 500 mm x 0.05 mm using a melt-extruded film (thickness 0.05 mm) of an adhesive fluorine-containing polymer (manufactured by AGC Inc., Fluon (registered trademark) EA-2000). Was produced.

(Manufacturing Example 2)
A PTFE sheet having a size of 500 mm × 500 mm × 1 mm was produced by skiving from a sintered molded body made of PTFE (manufactured by Starlight Industry Co., Ltd., ALP # 31000).

(Example 1)
As a metal substrate (reference numeral 1 in FIG. 1), a flat plate made of stainless steel (JIS G4304, size: 500 mm × 500 mm × 1.0 mm) was used, and the surface thereof was washed with acetone. The surface roughness Ra of the metal substrate was 0.13 μm as measured by a surface roughness measuring machine (Surfcom 1500DX3, manufactured by Tokyo Seimitsu Co., Ltd.).

A polyamic acid solution (manufactured by Ube Industries, Ltd., U varnish-S), which is a polyimide precursor, is spray-coated on the surface of the flat plate after washing with acetone so as to have a thickness of 0.05 mm, and allowed to stand at room temperature for 30 minutes. It was placed and dried to form a coating film. After drying, it is heated at 400 ° C. for 30 minutes in a hot air furnace to form a sintered body of a coating film (first primer layer, reference numeral 2 in FIG. 1) as a film containing a polyimide resin on the surface of a metal substrate. did.

The melt-molded sheet (second primer layer, reference numeral 3 in FIG. 1) obtained in Production Example 1 was placed on the surface of the sintered body containing the polyimide resin. The PTFE sheet (surface layer, reference numeral 4 in FIG. 1) obtained in Production Example 2 was placed on the surface of this melt-molded sheet.

When the melt-molded sheet is installed, the bond-preventing sheet (polyimide resin film, thickness) is such that the joint length (reference numeral L in FIG. 1B) of the melt-molded sheet and the sintered body is 30 mm. : 0.025 mm, reference numeral 5) in FIG. 1 (a) was placed between the sintered body of the coating film and the melt-molded sheet.

As described above, the layers of the stainless steel plate, the sintered body, the melt-molded sheet, and the PTFE sheet are laminated in this order, and the laminate with the joint prevention sheet partially provided is subjected to a compression molding machine (Kitakawa Seiki Co., Ltd.). After pressurizing for 300 seconds at a press temperature of 360 ° C and a pressure of 2 MPa using a vacuum press (manufactured by), cool while holding the pressure, remove the bonding prevention sheet, and heat resistance for testing with a bonding length of 30 mm. A sex laminate was obtained. The obtained heat-resistant laminate was cut so as to have a width of 16 mm, a length of 100 mm, and a joint length of 30 mm to prepare a test piece (reference numeral 6 in FIG. 1 (b)). It was visually confirmed that the above-mentioned crimped material of each layer having a joint length of 30 mm had the same thickness before and after crimping and had a four-layer structure using a magnifying glass. That is, the thickness of each layer before and after crimping is the same as before crimping. In the portion where the bonding prevention sheet is installed, the first primer layer and the second primer layer are not bonded, and serve as a gripping portion of the tensile tester in the peeling test.

(Comparative Example 1)
A test piece was prepared in the same manner as in Example 1 except that the sintered body containing the polyimide resin was not formed.

(Comparative Example 2)
A test piece was produced in the same manner as in Example 1 except that the melt-molded sheet obtained in Production Example 2 was not used.

(Comparative Example 3)
In the same manner as in Example 1, the laminate was heat-treated at 360 ° C. for 600 seconds using an electric furnace (manufactured by Kato Co., Ltd., TR051P-S) without pressurization instead of compression molding. A test piece was prepared.

From Table 1, it can be seen that in Example 1, no decrease in peel strength was observed even after exposure at 200 ° C. for 4 weeks, and the PTFE sheet and the metal base material maintained a good bond.

1 Metal substrate 2 1st primer layer 3 2nd primer layer 4 Surface layer 5 Bonding prevention sheet 6 Test piece L Bonding length

Claims (8)

A peel-resistant laminate having a non-adhesive surface in which a surface layer containing polytetrafluoroethylene (PTFE) is formed on the surface of a metal base material via first and second primer layers.
A melt-molded sheet containing a metal base material, a first primer layer composed of a film containing a polyimide resin formed on the surface of the metal base material, and an adhesive fluoropolymer formed on the surface of the first primer layer. A peel-resistant laminate, which is a pressure-bonded product of a second primer layer composed of and a laminate of surface layers composed of a fired sheet containing PTFE formed on the surface of the second primer layer. The peel-resistant laminate according to claim 1, wherein the film constituting the first primer layer is a sintered body of a liquid coating film containing a polyimide precursor or a sintered sheet of a polyimide resin. The peel-resistant laminate according to claim 1 or 2, wherein the adhesive fluorine-containing polymer has a carbonyl group and a melting point of 220 to 320 ° C. The peel-resistant laminate according to any one of claims 1 to 3, wherein the metal base material is a flat plate made of stainless steel or carbon steel. The peel-resistant laminate according to any one of claims 1 to 4, wherein the peel strength of the surface layer is 3 N / mm or more. The peel-resistant laminate according to any one of claims 1 to 5, wherein the thickness of the surface layer is 0.1 to 5 mm. A method for producing a peel-resistant laminate having a non-adhesive surface in which a surface layer containing polytetrafluoroethylene (PTFE) is formed on the surface of a metal base material via first and second primer layers.
First primer layer installation step of forming a film containing a polyimide resin on the surface of a metal substrate,
A second primer layer installation step of installing a melt-molded sheet containing an adhesive fluorine-containing polymer on the surface of a film containing a polyimide resin,
Surface layer installation step of installing a PTFE fired sheet on the surface of a melt-molded sheet containing an adhesive fluorine-containing polymer,
A crimping process of heating and compressing a laminate in which the first and second primer layers and the surface layer are installed on the surface of a metal substrate,
A method for producing a peel-resistant laminate including. The method for producing a peel-resistant laminate according to claim 7, wherein in the crimping step, crimping is performed under the conditions of a heating temperature of 340 to 380 ° C., a pressure of 1 to 5 MPa, and a pressurizing time of 5 to 10 minutes.

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