JP2008126425A - Metal plate having easily decomposable coating film and separation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal plate having an easily decomposable coating film capable of easily separating a laminate formed by integrating the metal plate and another member into each of constituent members, and a method for separating another member from the laminate formed by integrating the metal plate having the easily decomposable coating film and another member. <P>SOLUTION: The metal plate having the easily decomposable coating film has the easily decomposable coating film, which contains a polymer having a nitrogen-nitrogen double bond (-N=N-) and/or a nitrogen-carbon double bond (-C=N-) on its side chain, at least on its one side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique related to a metal plate on which a coating film is formed. Specifically, the present invention relates to a technique for easily separating a laminate in which another member is bonded to the metal plate into a metal material (base material) and the other member. .

  For the purpose of imparting functions such as corrosion resistance and durability, and design properties to the surface of metal plates such as steel plates and aluminum plates, products with increased added value by forming a coating film or bonding other members are provided. ing. In recent years, various laws aimed at solving waste problems and promoting recycling, such as the Basic Law for the Promotion of a Recycling-Oriented Society, are required to collect and reuse these products as well. . For example, interior building materials in which a plasterboard (other member) is bonded to a steel plate cannot be reused as they are, and in order to effectively use resources, the integrated steel plate and the plasterboard are separated. There is a need. However, such a product is difficult to separate and difficult to recycle because each material is firmly bonded to ensure durability during use.

  Paying attention to such problems, various methods for separating the laminate as described above for each constituent member have been proposed. In Patent Documents 1 to 3, when the base material and the other member are integrated, A technique using an organic thermal expandable fine particle (foaming agent) or an adhesive composition containing an organic thermal expandable fine particle and a water absorbent resin has been proposed. Patent Document 4 proposes a technique in which a coating layer containing a foaming agent is provided on the surface of a base material, and the base material and other members are integrated via the coating layer.

These technologies increase the volume of thermally expandable fine particles contained in the adhesive layer or paint layer by applying a predetermined operation (heating or water absorption operation) to the laminate comprising the adhesive layer or paint layer. Thus, by reducing the adhesion area between the metal plate or other member and the adhesive layer or the like, the adhesiveness between the two is reduced, and separation into the respective constituent members is facilitated.
JP 2003-171648 A International Publication No. 2002/55626 Pamphlet Japanese Patent Application Laid-Open No. 2000-93885 JP 2003-238721 A

  However, all the techniques described in the above patent documents are described in Patent Documents 1 and 2 because the heat-expandable particles and the water-absorbing resin are mixed with the base resin that is the base of the adhesive or paint. As shown, uniform mixing is difficult, and there may be some variation in peelability even on the surface where the coating film is formed. In addition, in order to form a good coating film, or to secure initial adhesive force and suppress a decrease in adhesive force over time, the amount of additive such as a foaming agent must be adjusted, which is complicated. .

  The present invention has been made paying attention to such circumstances, and its purpose is to easily disassemble a laminated body in which a metal plate and other members are integrated into individual constituent members. It is providing the method of isolate | separating another member from the laminated body with which the metal plate which has a coating film, the metal plate which has the said easily decomposable coating film, and another member were integrated.

  The metal plate having the easily decomposable coating film of the present invention capable of solving the above-described problems is a nitrogen-nitrogen double bond (-N = N-) and / or a nitrogen-carbon double in the side chain on at least one side. It is characterized by having an easily decomposable coating film containing a polymer having a bond (—C═N—).

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention are heated if a metal plate having a coating film containing a polymer having the above-mentioned side chain structure is used as the base material of the laminate. Thus, it was found that the laminate can be easily separated into a metal plate and other members, and the present invention has been completed. The polymer having the side chain structure has a property of decomposing into a low molecular compound by heating. At this time, since a part of the decomposition product becomes a gas, the contact area between the coating film and the base material or other member is reduced by the generation of the gas. Further, the polymer itself is also decomposed by heating. Therefore, it is considered that the adhesive strength between the constituent members of the laminate is further reduced, and separation into the constituent members is facilitated.

  The nitrogen-nitrogen double bond (—N═N—) and / or the nitrogen-carbon double bond (—C═N—) is a group consisting of a tetrazole derivative, a bistetrazole derivative, a triazole derivative, a guanidine derivative, and an azo compound. Preferably, the polymer is derived from one or more compounds selected from the group consisting of poly (1-vinyl-5-aminotetrazole).

  The coating film may further contain a low molecular foaming agent, and the low molecular foaming agent is selected from the group consisting of tetrazole derivatives, bistetrazole derivatives, triazole derivatives, guanidine derivatives, and azo compounds. One or more are preferred. When the low molecular foaming agent is included, the ratio of the low molecular foaming agent to 100 parts by mass of the polymer is preferably 1 to 200 parts by mass.

  The present invention also includes a method for peeling off other members formed on the surface of the metal plate. That is, the peeling method of the present invention is a method of separating the other member from a laminate in which the other member is laminated with or without an adhesive layer on the easily decomposable coating film side of the metal plate, This is a method characterized in that the laminate is heated to decompose the easily decomposable coating film so that other members can be easily separated from the metal plate.

  The laminated body in which the other member is provided in the easily decomposable coating film side of the said metal plate is also contained in the technical scope of this invention.

  The metal plate of this invention is used suitably for field | areas, such as a building material, household appliances, and office supplies. Moreover, according to the metal plate and the separation method of the present invention, the laminated body integrated with the metal plate can be separated for each constituent member by a simple operation. Therefore, even when used for interior building materials and the like that have been difficult to recycle in the past, each member can be reused because it can be easily separated into a metal plate and other components.

  The metal plate of the present invention includes a polymer having a nitrogen-nitrogen double bond (-N = N-) and / or a nitrogen-carbon double bond (-C = N-) in the side chain on at least one side. It has an easily decomposable coating film.

  First, the easily decomposable coating film provided on the surface of the metal plate of the present invention will be described. The easily decomposable coating film according to the present invention includes a polymer having a nitrogen-nitrogen double bond (-N = N-) and / or a nitrogen-carbon double bond (-C = N-) in the side chain. The polymer having such a side chain structure has a property of decomposing by heating. Although the mechanism of decomposition of the polymer having such a side chain structure is not grasped in detail, the reason why the easily decomposable coating film according to the present invention exhibits excellent peeling properties is considered as follows. ing.

  When a polymer having a nitrogen-nitrogen double bond and / or a nitrogen-carbon double bond in the side chain is heated, the side chain is decomposed into a low molecular weight compound, and a part thereof is a gas (nitrogen gas, ammonia Gas, carbon monoxide gas, carbon dioxide gas, etc.). And it is thought that decomposition | disassembly also occurs in a main chain structure following decomposition | disassembly of this side chain structure.

  As described in the above-mentioned patent document, conventionally, a coating film containing a foamable component is provided between the base material and the adherend (other member), and the base material and the adherend are provided. Many techniques for facilitating separation have been proposed. However, these techniques merely reduce the contact area between the coating film and the substrate or the adherend by simply foaming the foamable component. In a portion where no foamable component exists, it may be difficult to separate the substrate and the adherend. On the other hand, the easily decomposable coating film according to the present invention generates gas by heating, and simultaneously decomposes the polymer itself constituting the coating film. That is, in addition to the reduction of the contact area between the coating film and the metal plate or the adherend due to gas generation, the coating film itself becomes brittle due to the decomposition of the polymer main chain structure. Therefore, the metal plate and the adherend are integrated through the easily decomposable coating film according to the present invention (note that there may be an adhesive layer or the like between the coating film and the adherend). It is considered that the laminate can more easily separate the substrate and the adherend.

  The side chain structure (—N═N— structure and / or —C═N— structure) of the polymer is preferably derived from a compound having the structure. The compound having a —N═N— structure and / or —C═N— structure may be a chain compound or a cyclic compound (heterocyclic compound). Specific examples of the compound having a —N═N— structure and / or —C═N— structure include 5-aminotetrazole, 5-phenyltetrazole, 1-methyltetrazole, 2-methyltetrazole, and salts thereof. Tetrazole derivatives, bistetrazole derivatives such as 5,5′-bistetrazole, 5,5′-bistetrazoleamine, triazole derivatives such as 4-amino-1,2,4-triazole, 1,3,5-triamino Examples include guanidine derivatives such as guanidine and azo compounds such as azodicarbonamide (hereinafter, these may be referred to as nitrogen-containing organic compounds). In addition, a tetrazole derivative is preferable from the point of gas generation rate and handleability, and 5-aminotetrazole is particularly preferable.

  The nitrogen-containing organic compound is also known as a heating type foaming agent. For example, 5-aminotetrazole is 200 ° C., 5,5-bistetrazole is 269 ° C., 5-phenyltetrazole is 216 ° C., Bistetrazole diammonium decomposes at 325 ° C., azodicarbonamide at 200 ° C., and 1,3,5-triaminoguanidine nitrate decompose at 230 ° C. to generate gas. For example, poly (1-vinyl-5-aminotetrazole), which is a polymer having a structure derived from 5-aminotetrazole in the side chain, decomposes at 280 ° C. to generate gas. Therefore, the polymer having a structure derived from the nitrogen-containing organic compound in the side chain also has a property of being decomposed by heating to generate a gas.

  The thermal decomposition temperature of the polymer having the side chain structure is preferably 200 to 400 ° C. More preferably, it is 200-350 degreeC, More preferably, it is 220-300 degreeC. The thermal decomposition temperature was measured with a differential thermal analyzer (DSC) or a differential scanning calorimeter (DTA), and a significant weight loss was observed in a short time during thermogravimetry (TG). In this case, it means a temperature (temperature range) at which an exothermic peak is observed.

  The polymer according to the present invention includes a method for polymerizing a polymerizable monomer having the above -N = N- structure and / or -C = N- structure, or the above -N = N- as a side chain in the polymer. The polymer according to the present invention is obtained by the method of introducing a group having a structure and / or —C═N— structure, and the polymer according to the present invention has a polymerizable property having the aforementioned —N═N— structure and / or —C═N— structure. It is preferably obtained by polymerizing monomers.

  The polymerizable monomer having the -N = N- structure and / or -C = N- structure can be obtained by introducing a polymerizable reactive group into the nitrogen-containing organic compound. Examples of the polymerizable reactive group include groups containing a polymerizable unsaturated bond such as a vinyl group, a butenyl group, an allyl group, and a (meth) acryloyl group.

  The method for introducing a polymerizable reactive group into the nitrogen-containing organic compound is not particularly limited, and a conventionally known method may be employed. For example, in the case of introducing a vinyl group as a polymerizable reactive group into tetrazole, after alkylating N at the 1-position of tetrazole with chloroethanol in the presence of alkali, this is chlorinated, and the resulting tetrazole If a dehydrohalogenation reaction is performed using a chlorinated derivative, 1-vinyl-5-aminotetrazole and the like can be obtained. Moreover, a polymerizable reactive group can also be introduce | transduced similarly to tetrazole about bistetrazole and a triazole. In the case of a guanidine compound, a polymerizable reactive group can be introduced by forming a salt with guanidine and an unsaturated carboxylic acid (for example, (meth) acrylic acid).

  Thus, if the nitrogen-containing organic compound into which the polymerizable reactive group is introduced is radically polymerized by a known method, the polymer according to the present invention can be formed (reference: “Biocide Guanidine Containing Polymers. ”Synthesis, Structure and properties, by Nicolai A. Sivov, publisher VSP, published March 2006).

  The polymer according to the present invention may be obtained by polymerizing only one or two or more of the above nitrogen-containing organic compounds having a polymerizable reactive group as a monomer component, or other single amount having no nitrogen The body component may be copolymerized. Specific examples of copolymerizable monomer components having no nitrogen include (meth) acrylic acid esters, styrenes, α-olefins, vinyl esters, and (meth) acrylamides. Among these, poly (1-vinyl-5-aminotetrazole) obtained by polymerizing 1-vinyl-5-aminotetrazole as a monomer component is preferable. In addition, it is preferable to make it a copolymer using this monomer component from a viewpoint of improving the adhesiveness to the base material of a coating film.

  When the polymer according to the present invention contains other monomer components as copolymerization components, from the viewpoint of ensuring heat decomposability, the other monomer components are contained in 100% by mass of all monomer components. It is preferable to set it to 50 mass% or less. More preferably, it is 40 mass% or less, More preferably, it is 30 mass% or less.

  The polymer according to the present invention preferably has a mass average molecular weight (Mw) of 5,000 to 100,000. More preferably, it is 10,000-50,000, More preferably, it is 15,000-30,000. The weight average molecular weight of the polymer, and the value of the weight average molecular weight is a polystyrene conversion value measured by gel permeation chromatography (GPC).

  The polymerization method of the polymer according to the present invention is not particularly limited, and a solution polymerization method, an emulsion polymerization method, or the like can be employed. Among these, the emulsion polymerization method is preferable. For example, if the polymer according to the present invention is produced by emulsion polymerization, water can be used as the solvent. Usable emulsifiers are generally used in emulsion polymerization methods such as anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and polymeric surfactants. Emulsifiers. Specifically, anionic surfactants such as sorbitan trioleate, dialkyl sulfone succinate, alkyl diphenyl ether disulfonate, alkyl benzene sulfonate, naphthalene sulfonate derivatives, polyalkylene alkyl ether, polyalkylene sorbitan ester, etc. Nonionic surfactant etc. can be illustrated. The amount of the emulsifier used is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and 10% by mass or less with respect to 100% by mass of all monomer components. Preferably, it is 5 mass% or less more preferably.

  The polymerization method is not particularly limited, and a method using an initiator, a method of starting polymerization by irradiation with ultraviolet rays or heating, and the like can be employed. In addition, when using an initiator, usable initiators include peroxide initiators such as ammonium persulfate, potassium persulfate, benzoyl peroxide, lauryl peroxide, azobisisobutyronitrile, azobiscyclohexane. Examples include radical polymerization initiators such as azo compounds such as carbonitrile. These initiators are preferably 0.1 to 2% by mass with respect to 100% by mass of all monomer components. More preferably, it is 0.1-1 mass%, More preferably, it is 0.1-0.5 mass%.

  The polymerization temperature and polymerization time may be appropriately determined according to the type of monomer component used.

  The easily decomposable coating film according to the present invention only needs to contain a polymer having a —N═N— structure and / or a —C═N— structure in the side chain, for example, a polymer having such a side chain structure. Even if it consists of only other film components, it may contain. In addition, from the viewpoint of ensuring the effect of the present invention (heat decomposability of the coating film), it is preferable that the main component is the polymer having the side chain structure. The “main component” includes 50% by mass or more of a polymer containing a nitrogen-containing organic compound in a side chain when the total mass of the polymer and other coating film components is 100% by mass. Means that. More preferably, it is 60% or more, More preferably, it is 70% or more. An upper limit is not specifically limited, The polymer in which all the polymers which comprise a coating film were formed from the nitrogen-containing organic compound may be sufficient.

  Other components that can be adopted as coating film components include epoxy resins, unsaturated polyester resins, melamine resins, urethane resins, acrylic resins, silicone resins, fluorine resins, alkyd resins, phenol resins, etc. Thermosetting resins, thermoplastic resins such as saturated polyester resins, polyolefin resins, polyamide resins, acrylic resins, and the like can be given.

  Further, the coating film may contain a low molecular foaming agent as a foaming component other than the above polymer in order to enhance the heat decomposability. That is, the gas generated from the low molecular type foaming agent further reduces the adhesion area between the coating film and the metal plate, so that the substrate and the adherend are more easily separated.

  Here, the low molecular type foaming agent refers to a compound (foaming agent) that self-decomposes by heating to generate gas, and both organic foaming agents and inorganic foaming agents can be used. The organic foaming agent preferably has a weight average molecular weight of about 100 to 500. For example, azo compounds such as azodicarbonamide, barium azodicarboxylate, azobisisobutyro and tolyl; N, N′-dinitroso Nitroso compounds such as pentamethylenetetramine, nitroso compounds such as N, N-dinitroso-N, N-dimethylterephthalamide; p-toluenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonylhydrazide), hydrazodicarbonamide, diphenyl Sulfonyl hydrazide compounds such as sulfone-3,3-disulfonylhydrazide; Tetrazole derivatives and bistetrazole derivatives such as 5-aminotetrazole, 5-phenyltetrazole, 1-methyltetrazole, 5,5′-bistetrazole; Gua Derivative; p-toluenesulfonyl semicarbazide; trihydrazinotriazine; biurea like. Examples of the inorganic foaming agent include carbonates such as sodium bicarbonate, sodium bicarbonate, zinc carbonate, and potassium bicarbonate: azides such as sodium azide; and thermally expandable microcapsules. Among these, azodicarboxamide and 5-aminotetrazole are preferable. The said low molecular type foaming agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  When other foaming components as described above are used, it is preferable to employ a low molecular foaming agent having a thermal decomposition temperature sufficiently higher than the temperature required for the drying or curing reaction of the coating film. . The thermal decomposition temperature of the low molecular weight foaming agent is preferably at least 20 ° C. higher than the heating temperature (drying temperature) when forming the coating film.

  Moreover, when using these low molecular type foaming agents, you may use the adjuvant for promoting the decomposition | disassembly of the said low molecular type foaming agent. For example, zinc stearate is mentioned as a decomposition aid of azodicarbonamide (foamable component).

  The amount of the low molecular foaming agent used is preferably 0 to 200 parts by mass with respect to 100 parts by mass of the solid content (resin content) of the entire polymer constituting the coating film. More preferably, it is 0-100 mass parts. When the amount of the foaming agent is too large, problems such as a decrease in the adhesion of the coating film before decomposition may occur.

  The easily decomposable coating film according to the present invention is a coating film forming solution (coating liquid) obtained by dissolving or dispersing a polymer having the nitrogen-containing organic compound in the side chain in a solvent, on a metal plate, Obtained by drying and / or curing. The solvent for dissolving or dispersing the polymer may be any solvent that can dissolve the polymer, but preferably has a boiling point of 30 ° C. or lower than the thermal decomposition temperature of the polymer. When the boiling point of the solvent is close to the thermal decomposition temperature of the polymer, the coating film may be decomposed (foamed) simultaneously with the removal of the solvent when the coating film is dried. Preferred solvents include dimethyl sulfoxide (DMSO), dimethylformamide and the like. These solvents may be used alone or in combination of two or more.

  Moreover, at this time, as long as the heat decomposability of the easily decomposable coating film according to the present invention is not impaired, a thermosetting resin such as an epoxy resin or a polyester resin or a thermoplastic resin is mixed as another coating film forming component. Also good. It is desirable that the amount of these resins added does not exceed the amount of the polymer containing the nitrogen-containing organic compound as the main component. Preferably, it is recommended to adjust so that it may become the said coating-film composition.

  The coating solution preferably has a viscosity (room temperature; 25 ° C.) measured with a B-type viscometer of 50 to 2000 mPa · s, more preferably 100 to 1000 mPa · s, and still more preferably 100 to 800 mPa · s. s. When the viscosity of the coating solution exceeds the above range, it tends to be difficult to form a coating film. In addition, in the coating liquid according to the present invention, as long as the heat decomposability of the easily decomposable coating film according to the present invention is not impaired, a surface conditioner, a viscosity modifier, etc. are used to adjust the properties of the coating liquid. May be added.

  The coating solution prepared as described above is applied onto a metal plate and dried to form a coating film. As a coating method of these coating liquids, a roll coating method, a blade coating method, a screen method, a curtain flow method, an electrostatic coating, a spray coating, a dip coating method, a bar coater, a coating method using a spin coater, etc. Is mentioned.

  The coating film is preferably dried at a temperature about 30 ° C. higher than the boiling point of the solvent used and at a temperature 30 ° C. lower than the decomposition temperature of the polymer or foaming agent that forms the coating film. If the drying temperature is too high, the coating layer may be peeled off or decomposed. On the other hand, if the drying temperature is too low, drying may be insufficient. More preferably, it is 100-200 degreeC, More preferably, it is 150-200 degreeC. Examples of the drying method usable at this time include a hot air drying method and an induction heating method.

  The thickness of the easily decomposable coating film according to the present invention formed as described above is preferably about 10 to 100 μm, more preferably 10 to 50 μm. When the thickness is less than 10 μm, it may be difficult to separate the metal plate and the adherend. On the other hand, when it is thicker than 100 μm, it takes a long time to dry the coating film, which may cause problems such as a decrease in productivity and a decrease in strength and adhesion of the coating film.

  As a metal plate which forms the easily decomposable coating film which concerns on this invention, steel plates, such as an aluminum plate and stainless steel, a plated steel plate, a copper plate, a titanium plate, a tin plate, etc. are mentioned. In addition, the easily decomposable coating film according to the present invention may be provided only on one side of the metal plate, or both surfaces of the base material or the entire surface of the base material are covered with the easily decomposable coating film according to the present invention. May be.

  The metal plate of the present invention can be used for various applications. For example, it can be used for building materials, home appliances, office supplies, etc. in a state where other members such as gypsum board and heat insulating material are laminated and integrated.

  The laminate of the present invention is obtained by laminating and integrating other members on the surface of the metal plate of the present invention provided with the above-described easily decomposable coating film, that is, the easily peelable coating film forming surface. Since the laminated body of this invention has laminated | stacked the other member through the said easily decomposable coating film, a base material and an other member can be easily isolate | separated by heating this laminated body.

  Moreover, as another member laminated | stacked on the surface of the said coating film, the coating film containing a gypsum board, a heat insulating material, a nonwoven fabric, or a pigment is mentioned. In addition, the joining method of these other members and the metal plate used as the base material of the laminated body is not particularly limited as long as it is provided on the easily decomposable coating film forming side according to the present invention. An acrylic adhesive, a polyolefin adhesive, a polyurethane adhesive, an epoxy adhesive, etc.), or may be laminated and integrated without using an adhesive.

  The separation method of the other member of the present invention is to separate the other member from the laminate in which the other member is laminated on the easily degradable coating film side of the metal plate according to the present invention with or without an adhesive layer. The method is characterized in that the laminate is heated to decompose the easily decomposable coating film so that other members can be easily separated from the metal plate.

  As described above, since the laminate according to the present invention has the above-described easily decomposable coating film between the metal plate and the other member, the laminate can be easily separated by heating the laminate. Can do.

  What is necessary is just to determine suitably the heating temperature at the time of isolate | separating a laminated body into a metal plate and another member according to the kind of polymer contained in the said easily decomposable coating film, For example, it is 200-350 degreeC. It is preferable to do this. More preferably, it is 250-300 degreeC. If the temperature is too low, the decomposition reaction does not proceed sufficiently, and if it is too high, the substrate or other member itself may be deteriorated.

  In addition, although what is necessary is just to adjust a heating time suitably with the kind of base material, it is preferable to set it as 5 minutes or more, for example. More preferably, it is 7 minutes or more, More preferably, it is 10 minutes or more, It is preferable that it is 1 hour or less, More preferably, it is 30 minutes or less. Note that the heating time is a guide only, and may be set as appropriate according to the easily decomposable coating film, the metal plate to be separated, and other members. For example, when the metal plate is thick (1 mm or more) or the thermal conductivity of the metal plate is small, it is preferable to lengthen the heating time to sufficiently decompose the easily decomposable coating film on the metal plate surface. For example, when the coating film contains poly (1-vinyl-aminotetrazole), it is preferable to heat the laminate at 300 ° C. for 5 minutes or more.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range.

[Measurement of thermal decomposition temperature]
Using a differential thermal balance (“Thermo Plus2 TG / DTA” manufactured by Rigaku Corporation), the temperature was increased from room temperature (25 ° C.) to 800 ° C. at 10 ° C./min in the air. The position at which the TG curve began to tilt was calculated using the software attached to the apparatus. The DTA (differential heat) measurement was performed using alumina powder as a reference sample.

<Synthesis of polymer constituting easily degradable coating film>
Synthesis of 1-vinyl-5-aminotetrazole
1-Vinyl-5-aminotetrazole (monomer) was synthesized according to the method described in US 3,332,353.

  Synthesis Example 1: Synthesis of 1- (2-hydroxyethyl) -5-aminotetrazole

  A 1-liter three-necked flask equipped with a condenser and a dropping funnel is charged with 90 g (10.6 mol) of 5-aminotetrazole (Toyo Kasei Kogyo), 100 ml of ion-exchanged water and a small amount of phenolphthalein, and the color of phenolphthalein is developed. Until the above was confirmed, 59.4 g (10.6 mol) of a 6.7 M potassium hydroxide (KOH) aqueous solution was added to neutralize the mixed solution.

  This solution was heated to reflux, and 90 g of 2-chloroethanol was added dropwise over 15 minutes. The obtained solution was refluxed for 18 hours, and then the solvent was distilled off at 60 to 70 ° C. under reduced pressure to obtain a syrupy crude product.

  This crude product was extracted twice with 100 ml of boiling acetone, the extraction solvents were combined, and the solvent was distilled off under reduced pressure. Subsequently, the obtained crude 1- (2-hydroxyethyl) -5-aminotetrazole was recrystallized from boiling ethanol to obtain 1- (2-hydroxyethyl) -5-aminotetrazole (13.1 g, yield). 10.1%).

  Synthesis Example 2: Synthesis of 1- (2-chloroethyl) -5-aminotetrazole

  In a 200 ml three-necked flask, 60 ml of thionyl chloride was placed, and 17.5 g (0.136 mol) of 1- (2-hydroxyethyl) -5-aminotetrazole was added while cooling the reaction system to 5 ° C. or lower with an ice bath. I added it little by little. After the addition of 1- (2-hydroxyethyl) -5-aminotetrazole, the resulting slurry was heated to 62-68 ° C. and refluxed for 4 hours. Thereafter, excess thionyl chloride was distilled off while collecting with a trap cooled with liquid nitrogen under reduced pressure. After adding 95% ethanol and 20 ml of water to the residue, the solvent was distilled off under reduced pressure. The crude product was recrystallized from warm water to give 1- (2-chloroethyl) -5-aminotetrazole (13.7 g, yield 68.3%).

  Synthesis Example 3: Synthesis of 1-vinyl-5-aminotetrazole

In a 200 ml three-necked flask equipped with a dropping funnel and a condenser, 1- (2-chloroethyl) -5-aminotetrazole 19 g (0.17 mol) and hydroquinone 0.05 g (4.54 × 10 ⁻⁴ mol) Was dissolved in 70 ml of methanol, and a solution of 7.23 g of 85% aqueous potassium hydroxide solution (KOH) dissolved in 50 ml of methanol was added dropwise thereto over 30 minutes with stirring. After completion of the dropwise addition, the mixed solution was refluxed for 1 hour, then the reaction solution was cooled to 20 ° C., and the precipitated KCl was filtered off, and then the solvent was distilled off from the filtrate under reduced pressure. The oily substance thus obtained was recrystallized from warm water to obtain pale yellow crystals as a product (11.4 g, yield 60.4%). The melting point of the product was 157-158 ° C.

The structural analysis of the product was performed by ¹³ C-NMR measurement. The product is dissolved in dimethyl sulfoxide-d6 to prepare a sample solution, and using NMR (“AL400 FT-NMR”, manufactured by JEOL Ltd.), measurement conditions at room temperature (25 ° C.) and 512 times of integration When the sample solution was measured, peaks were confirmed at 104.9 ppm, 125.3 ppm, and 153.8 ppm. Since this peak substantially coincided with the chemical shift calculated from the structure of 1-vinyl-5-aminotetrazole, it was confirmed that the product was 1-vinyl-5-aminotetrazole.

Polymerization Example: Polymerization of 1-vinyl-5-aminotetrazole Using 1-vinyl-5-aminotetrazole obtained in the above synthesis example as a monomer (monomer), poly (1-vinyl-5- 5) was prepared by emulsion polymerization. Aminotetrazole) was prepared. The physical properties of the produced polymer were confirmed according to the method described in SVLevchik et al. (Polymer Degradation and Stability 47 (p.333-338, (1995))).

  While stirring an aqueous solution obtained by adding 15 drops of sorbitan trioleate to 80 ml of distilled water, 0.1 mol of 1-vinyl-5-aminotetrazole was added (monomer solution). The emulsion preparation and the polymerization reaction were performed while keeping the temperature of the aqueous solution at 65 ° C. and bubbling nitrogen into the water.

  After adding 1 ml of a solution obtained by dissolving 0.03 g of ferrous sulfate heptahydrate in 100 ml of distilled water, 0.025 g of ammonium persulfate (ammonium peroxodisulfate), and 0.025 g of sodium metabisulfite to the above monomer solution While stirring, the polymerization reaction was carried out for 48 hours to obtain a polymer. The produced polymer was separated by filtration, dried, and washed with water to remove inorganic salts and surfactant (sorbitan trioleate). Next, the obtained polymer was dissolved in carbon tetrachloride and then precipitated in 500 ml of cyclohexane. The precipitate was collected by filtration and dried under vacuum to obtain a polymer (yield). 90%).

^When structural analysis of the polymer was performed by ¹³ C-NMR measurement (temperature 25 ° C., cumulative number 50,000 times, dimethyl sulfoxide-d6), peaks were confirmed at 38.0 ppm, 50.0 ppm, and 154.1 ppm. The polymer obtained by poly (1-vinyl-5-aminotetrazole) was almost identical to the chemical shift (155.6 ppm) calculated from the structure of poly (1-vinyl-5-aminotetrazole). Identified. The thermal decomposition starting temperature of this polymer was 240 ° C., and the exothermic peak observed by DTA (suggested thermal analyzer, manufactured by Rigaku Corporation) was 285 ° C.

Experimental example 1
A dimethyl sulfoxide solution (concentration: 10% by mass, solid content: 10%) of poly (1-vinyl-5-aminotetrazole) prepared by using the polymer obtained in the above polymerization example was used to coat the surface with a No. 75 bar coater. A metal plate which is applied on a degreased aluminum plate (100 mm × 150 mm, thickness 0.5 mm), dried with a hot air dryer at 180 ° C. for 5 minutes, and having an easily decomposable coating film (10 μm) on the aluminum plate. Was made.

Experimental example 2
To a dimethyl sulfoxide solution of poly (1-vinyl-5-aminotetrazole) (concentration: 10% by mass, solid content: 10%), 0.5 g of 5-aminotetrazole powder is added, and the poly ( The solid content ratio of 1-vinyl-5-aminotetrazole) and 5-aminotetrazole was adjusted to 50:50.

  The prepared solution for forming a coating film was applied on an aluminum plate in the same manner as in Example 1 to produce a metal plate having an easily decomposable coating film (film thickness 30 μm).

Experimental example 3
Aluminum plate in the same manner as in Example 1 except that the solid content ratio of poly (1-vinyl-5-aminotetrazole) and 5-aminotetrazole in the coating film forming solution was adjusted to 75:25. A metal plate having an easily decomposable coating film was prepared (film thickness 20 μm).

Experimental Example 4
Add azodicarbonamide powder (Wako Pure Chemical Industries) and zinc stearate powder (Wako Pure Chemical Industries) to poly (1-vinyl-5-aminotetrazole) dimethyl sulfoxide solution (concentration: 10% by mass). Example 1 except that the solid content ratio of poly (1-vinyl-5-aminotetrazole), azodicarbonamide powder and zinc stearate powder in the forming solution was adjusted to 50:25:25. Similarly, a metal plate having an easily decomposable coating film on an aluminum plate was prepared (film thickness 20 μm).

Experimental Example 5
A dimethyl sulfoxide solution of poly (1-vinyl-5-aminotetrazole) (concentration 10% by mass), a bisphenol F type epoxy resin (Epicoat 807, manufactured by Japan Epoxy Resin Co., Ltd.) and an amine-based latent curing agent (“Amicure (registered) (Trademark) PN-40 ”(manufactured by Ajinomoto Fine Chemical Co., Ltd.) mixed at a ratio of 10: 6 (mass ratio), a dimethyl sulfoxide solution (concentration 10 mass%) was mixed at a ratio of 75:25 (mass ratio), A solution for forming a coating film was prepared. This was coated on an aluminum plate with a No. 75 bar coater and dried at 180 ° C. for 5 minutes to produce a metal plate having an easily decomposable coating film on the aluminum plate. The film thickness of the easily decomposable coating film formed at this time was 20 μm.

Experimental Example 6
Using the coating film forming solution of Experimental Example 5, the total mass of solids derived from poly (1-vinyl-5-aminotetrazole), the epoxy resin, and the curing agent in the coating film forming solution; It adjusted so that ratio with the solid content mass originating in an aminotetrazole powder might be set to 75:25. This was applied onto an aluminum plate and dried in the same manner as in Example 5 to produce a metal plate having an easily decomposable coating film (film thickness 20 μm).

Experimental Example 7
A commercially available liquid epoxy resin (solid content 30%, manufactured by Tanaka Chemical Co., Ltd.) is applied onto an aluminum plate with a No. 60 bar coater and dried at 180 ° C. for 5 minutes using a hot air dryer to cure the resin. The metal plate which has a coating film was made. The thickness of the coating film was 20 μm.

Experimental Example 8
Using the same commercially available epoxy resin as in Experimental Example 7, the coating film forming solution was adjusted so that the mass ratio of the solid content derived from the epoxy resin and the 5-aminotetrazole powder was 75:25 (mass ratio). A coating film was formed in the same manner as in Experimental Example 7 except that the adjustment was made. The thickness of the coating film was 20 μm.

Experimental Example 9
Using the commercially available epoxy resin used in Experimental Example 7, the ratio of the solid content derived from the epoxy resin to the solid content mass derived from each of azodicarbonamide and zinc stearate was 75: 12.5: 12. The coating film forming solution was adjusted so as to be .5, and this was coated on an aluminum plate with a No. 60 bar coater and dried at 180 ° C. for 5 minutes using a hot air dryer to cure the resin. A metal plate having a coating film was prepared (film thickness 20 μm).

Experimental Example 10
An adhesive (“Araldite Standard”, manufactured by Huntsman Advanced Materials) was applied to a 20 mm portion from the long side end of the aluminum plate (coating film not formed) whose surface was degreased (aluminum plate 1). Next, an aluminum plate having the same shape as the aluminum plate 1 (the aluminum plate 2, the coating film and the adhesive layer are not formed) is prepared, and the long side end portion of the aluminum plate 2 is moved from the long side end portion of the aluminum plate 1. As shown in FIG. 1, the two aluminum plates are stacked so that the portion 20 mm away from the end of one long side of each aluminum plate becomes an adhesive portion. Pasted together.

  Table 1 shows the compositions of the coating film forming solutions used in Experimental Examples 1 to 10.

[Adjustment test sample evaluation and evaluation method]
1. Preparation of test piece The metal plate manufactured in the above experimental example is cut into 110 mm × 25 mm, and an adhesive (“Araldite Standard”, manufactured by Huntsman Advanced Materials) is applied to a portion 20 mm from one end of the long side. It apply | coated and the adhesive bond layer (100 micrometers in thickness) was formed (metal plate 1). Next, the end portion of the long side of the metal plate (metal plate 2) having the same shape as that of the metal plate 1 is placed on the end portion of the adhesive layer formed on the metal plate 1 so that the coating film forming surface is in contact with the adhesive. As shown in FIG. 1, the two metal plates were bonded so that the 20 mm portion from the long side edge of each metal plate would be the bonded portion, and allowed to stand overnight at room temperature, then at 60 ° C. for 5 hours. Cured.

2. Adjustment of test piece for easy peelability measurement The test piece prepared in the same manner as above was heated in a hot air dryer at 250 ° C. or 300 ° C. for 5 minutes to prepare a test piece for easy peelability evaluation.

3. Measurement of adhesive strength Each test piece adjusted in 1 and 2 above is mounted on an Instron 4505 universal testing machine, pulled at room temperature and at a speed of 50 mm / min, the adhesive part peels off, and the load when the two metal plates separate (N) was measured and used as the adhesive strength. The evaluation results of each test piece are shown in Table 1.

  In addition, the value of the change rate of the adhesive strength in Table 1 is the relative adhesive strength after heating (after coating film decomposition) when the adhesive strength before sample heating (before coating film decomposition) is 100%. In the expression, “− (minus)” indicates that the adhesive strength after heating is lower than the adhesive strength before heating the sample, and “+ (plus)” indicates that the adhesive strength after heating is low. It shows that the adhesive strength has increased.

  As is clear from Table 1, the metal plate having the easily decomposable coating film of the present invention is compared with the conventional examples (experimental examples 7 to 9) in which the coating film forming component and the low molecular foaming agent are combined. In the example used (Experimental Examples 1-6), it turns out that the adhesive strength is falling significantly by heating. Moreover, it turns out that the adhesive strength after a heating can further be reduced by using together a low molecular-type foaming agent (Experimental example 2, 3, and 6). On the other hand, in the example which does not have the easily decomposable coating film according to the present invention, the decrease in the adhesive strength is small, and compared with the metal plates of Experimental Examples 1 to 6, separation of the laminate (metal plate and other members Separation) is considered difficult.

  The metal plate having the easily decomposable coating film of the present invention is suitably used in the fields of building materials, home appliances, office supplies and the like. Moreover, according to the metal plate and the separation method of the present invention, the laminated body integrated with the metal plate can be separated for each constituent member by a simple operation. Therefore, even when used for interior building materials and the like that have been difficult to recycle in the past, each member can be reused because it can be easily separated into a metal plate and other components.

It is a schematic diagram of the sample for a test in an Example.

Claims (8)

  At least one side has an easily decomposable coating film containing a polymer having a nitrogen-nitrogen double bond (-N = N-) and / or a nitrogen-carbon double bond (-C = N-) in the side chain. A metal plate characterized by   A group in which the nitrogen-nitrogen double bond (—N═N—) and / or the nitrogen-carbon double bond (—C═N—) is composed of a tetrazole derivative, a bistetrazole derivative, a triazole derivative, a guanidine derivative, or an azo compound. The metal plate according to claim 1, wherein the metal plate is derived from one or more compounds selected from:   The metal plate according to claim 1 or 2, wherein the polymer is poly (1-vinyl-5-aminotetrazole).   The metal plate according to claim 1, wherein the coating film further contains a low molecular foaming agent.   The metal plate according to claim 4, wherein the low molecular foaming agent is one or more selected from the group consisting of a tetrazole derivative, a bistetrazole derivative, a triazole derivative, a guanidine derivative, and an azo compound.   The metal plate according to claim 4 or 5, wherein a ratio of the low molecular foaming agent to 1 to 200 parts by mass with respect to 100 parts by mass of the polymer. A method for separating the other member from a laminate in which the other member is laminated with or without an adhesive layer on the easily decomposable coating film side of the metal plate according to claim 1,
A method for separating other members, wherein the laminate is heated to decompose the easily decomposable coating film so that the other members can be easily separated from the metal plate.   The laminated body in which the other member is provided in the easily decomposable coating film side of the metal plate in any one of Claims 1-6.