Primer composition, laminate, article, and method for manufacturing the laminate

Abstract

The present invention provides a primer composition that can suppress foaming of a laminate when used to form a primer layer in a laminate. [Solution] A primer composition for rotlining, characterized by comprising a perfluoropolymer powder or pellet, an amine-based antioxidant with a molecular weight of 1000 or less, and at least one predetermined powder selected from the group consisting of an organic sulfur-containing compound with a molecular weight of 1000 or less.

Description

[Technical Field]

[0001] This disclosure relates to primer compositions, laminates, articles, and methods for manufacturing laminates. [Background technology]

[0002] Rotary lining methods are known. For example, Patent Document 1 discloses a rotary lining method in which a powder composition containing a heat-meltable fluororesin is introduced into a cylindrical article to be lined, the cylindrical article is rotated, and the powder is uniformly pressed and adhered to the article by the centrifugal force generated by the rotation, and the heat-meltable fluororesin is welded to the surface of the article to be lined by heating. Patent Document 2 discloses mixing metal powder into the fluororesin to suppress the generation of bubbles. Patent Document 3 discloses using a composition containing a non-bubble-promoting metal powder. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2000-237682 [Patent Document 2] Japanese Patent Application Publication No. 4-267744 [Patent Document 3] Special Publication No. 2006-509095 [Overview of the project] [Problems that the invention aims to solve]

[0004] The present disclosure aims to provide a primer composition that can suppress foaming of a laminate when used to form a primer layer in the laminate. [Means for solving the problem]

[0005] This disclosure relates to a primer composition for rotlining, characterized by comprising a perfluoropolymer powder or pellet, an amine-based antioxidant with a molecular weight of 1000 or less, and at least one predetermined powder selected from the group consisting of an organic sulfur-containing compound with a molecular weight of 1000 or less.

[0006] Preferably, the perfluoropolymer is a copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether), a copolymer of tetrafluoroethylene and hexafluoropropylene, or a copolymer of tetrafluoroethylene, hexafluoropropylene, and perfluoro(alkyl vinyl ether). Preferably, the content of the perfluoropolymer powder or pellets is 95.0% by mass or more and 99.5% by mass or less, based on the total amount of the primer composition. Preferably, the content of the predetermined powder is 0.5% by mass or more and 5.0% by mass or less, relative to the total amount of the primer composition. Preferably, the average particle size of the perfluoropolymer powder or pellets is 150 μm or more and 500 μm or less. Preferably, the apparent density of the perfluoropolymer powder or pellets is 0.7 g / mL or higher. The primer composition preferably does not contain metal powder. The aforementioned primer composition preferably does not contain nitrogen-containing polymers or sulfur-containing polymers. The perfluoropolymer is a copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether), a copolymer of tetrafluoroethylene and hexafluoropropylene, or a copolymer of tetrafluoroethylene, hexafluoropropylene, and perfluoro(alkyl vinyl ether). The content of the perfluoropolymer powder or pellets is 95.0% by mass or more and 99.5% by mass or less, based on the total amount of the primer composition. The amine-based antioxidant is a phenylenediamine compound or a diphenylamine compound. The aforementioned organic sulfur-containing compound is a mercaptobenzothiazole compound or a metal salt thereof. Preferably, the content of the predetermined powder is 0.5% by mass or more and 5.0% by mass or less, relative to the total amount of the primer composition.

[0007] This disclosure also relates to a laminate comprising a first layer which is a substrate layer and a second layer provided on the first layer, wherein the first layer is a rotlining film formed from the primer composition.

[0008] The second layer is a rotlining film formed from the powder or pellets of the perfluoropolymer, and it is preferable that the second layer does not contain amine-based antioxidants, organic sulfur-containing compounds, or metal powders. The second layer is a rotlining film formed from the powder or pellets of the perfluoropolymer, and it is preferable that the perfluoropolymer content in the second layer is 99% by mass or more of the total amount of the second layer. The thickness of the first layer is preferably 300 μm or more.

[0009] This disclosure is also an article having the laminate.

[0010] This disclosure relates to a method for manufacturing a laminate, comprising a first layer formation step of forming a first layer on a substrate and a second layer formation step of forming a second layer on the first layer, wherein in the first layer formation step, the first layer is formed from the primer composition by rotlining.

[0011] In the aforementioned second layer formation step, it is preferable to form the second layer by rotlining. [Effects of the Invention]

[0012] The primer composition of this disclosure can suppress foaming of a laminate when used to form a primer layer in a laminate.

Mode for Carrying Out the Invention

[0013] Hereinafter, the present disclosure will be described in detail.

[0014] [Primer Composition] The primer composition of the present disclosure is a composition for rotolining used in rotolining. In the present disclosure, rotolining means a coating method by rotational molding.

[0015] The primer composition of the present disclosure is used for forming a primer layer. The primer layer is provided between a base material and a top coat layer, and enhances the adhesion between the base material and the top coat layer.

[0016] When attempting to apply a rotolining film from fluororesin powder, there is a problem that foaming occurs due to thermal decomposition of the fluororesin during heat treatment. In order to suppress foaming, it is known to add metal powder to the fluororesin powder. However, when the metal powder is contained in the primer layer, there is a problem that foaming remains in the laminate (especially the top coat layer). Therefore, the primer composition of the present disclosure contains at least one predetermined powder selected from the group consisting of an amine-based antioxidant having a molecular weight of 1000 or less and an organic sulfur-containing compound having a molecular weight of 1000 or less. By containing such a predetermined powder in the primer layer, the problem that foaming remains not only in the primer layer but also in the top coat layer can be solved. Thus, when the primer composition of the present disclosure is used for forming the primer layer of a laminate, foaming in the primer layer of the laminate can be suppressed, and furthermore, foaming in the top coat layer can also be suppressed.

[0017] The primer composition of this disclosure comprises a perfluoropolymer powder or pellet and a predetermined powder. In this disclosure, the "predetermined powder" is defined as at least one powder selected from the group consisting of amine-based antioxidants with a molecular weight of 1000 or less and organic sulfur-containing compounds with a molecular weight of 1000 or less. The primer composition of this disclosure is in the form of a powder, pellets, or a mixture of powders and pellets. The perfluoropolymer and the predetermined powder contained in the primer composition of this disclosure will be described below.

[0018] <Perfluoropolymer> The perfluoropolymers used in this disclosure are in powder or pellet form. Examples of perfluoropolymers used in this disclosure include those obtained by polymerization using one or more perfluoro monomers as monomer components. Examples of perfluoro monomers include tetrafluoroethylene [TFE], hexafluoropropylene [HFP], and perfluoro(alkyl vinyl ether) [PAVE]. Examples of PAVE include perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether) [PEVE], and perfluoro(propyl vinyl ether) [PPVE]. The main chain of the perfluoro monomer consists of carbon atoms, fluorine atoms, and optionally oxygen atoms (e.g., ether oxygen atoms), and does not contain CH or CH2. Furthermore, when multiple monomer components of the perfluoropolymer are used, there is no particular upper limit to the number of monomer components; for example, there may be 10 types, 5 types, or 3 types.

[0019] The perfluoropolymer used in this disclosure may be obtained by polymerization using only perfluoro monomers as monomer components. However, the perfluoropolymer used in this disclosure may also be obtained by polymerization using one or more of the above perfluoro monomers and one or more of comonomers as monomer components. Comonomers are monomers copolymerizable with perfluoro monomers. Examples of comonomers include chlorofluorovinyl monomers such as chlorotrifluoroethylene; fluorovinyl monomers such as vinylidene fluoride and trifluoroethylene; and monomers having carbonyl group-containing groups. Examples of monomers having carbonyl group-containing groups include cyclic monomers having acid anhydride residues, monomers having carboxyl groups, vinyl esters, and (meth)acrylates. Examples of cyclic monomers having acid anhydride residues include itaconic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic acid anhydride, and maleic anhydride. When comonomers are used, the comonomer content is not particularly limited as long as perfluoro monomers are the main component, but may be, for example, 30 mol% or less, 10 mol% or less, 5 mol% or less, or 1 mol% or less, relative to the total amount of monomer components of the perfluoropolymer.

[0020] Because the formed film has high heat resistance and chemical resistance and is suitable for protecting the substrate, perfluoropolymer copolymerized with TFE is preferred. For the same reason, the perfluoropolymer is more preferably a copolymer of TFE and PAVE [PFA], a copolymer of TFE and HFP [FEP], or a copolymer of TFE, HFP, and PAVE. The primer composition may contain only one of these copolymers, or two or more (for example, two or three).

[0021] The perfluoropolymer copolymerized using the above TFE is preferably one in which the content of TFE units relative to the total amount of perfluoropolymer monomer units is 75 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, and most preferably 95 mol% or more. The upper limit of the TFE unit content is not particularly limited, but may be, for example, 99.9 mol% or 99 mol%. The higher the TFE unit content, the more the heat resistance and chemical resistance of the formed film tend to improve. On the other hand, the lower the TFE unit content, the easier the perfluoropolymer melts and the more the moldability tends to improve.

[0022] The PFA used is preferably a copolymer with a molar ratio of TFE units to PAVE units (TFE units / PAVE units) of 70 / 30 to 99.9 / 0.1, more preferably 80 / 20 to 99.5 / 0.5, even more preferably 90 / 10 to 99 / 1, and most preferably 95 / 5 to 98.5 / 1.5. The higher the number of TFE units, the better the heat resistance and chemical resistance of the formed film tend to be. On the other hand, the lower the number of TFE units, the easier the PFA melts, and the better the moldability tends to be.

[0023] The above-mentioned FEP is preferably a copolymer with a molar ratio of TFE units to HFP units (TFE units / HFP units) of 70 / 30 to 99 / 1, more preferably 80 / 20 to 95 / 5, and even more preferably 85 / 15 to 93 / 7. The more TFE units there are, the better the heat resistance and chemical resistance of the formed film tends to be. On the other hand, the fewer TFE units there are, the easier the FEP melts and the better the moldability tends to be.

[0024] As the copolymer of TFE, HFP, and PAVE described above, a copolymer in which the molar ratio of the total number of TFE units and HFP units to the number of PAVE units (total number of TFE units and HFP units / PAVE units) is 99.9 / 0.1 to 90 / 10 is preferred, and a copolymer in which the ratio is 99 / 1 to 95 / 5 is more preferred. The molar ratio of TFE units to HFP units in the copolymer of TFE, HFP, and PAVE is preferably the same as the molar ratio of TFE units to HFP units in FEP.

[0025] To maintain an appropriate amount of heat stabilizers and other components in the primer layer and to sufficiently reduce the elution of these components, the content of perfluoropolymer powder or pellets is preferably 85.0% by mass or more, and more preferably 95.0% by mass or more, relative to the total amount of the primer composition.

[0026] In order to ensure a sufficient amount of heat stabilizers and other components in the primer layer and to effectively suppress foaming in the primer layer, it is preferable that the content of perfluoropolymer powder or pellets be 99.5% by mass or less of the total amount of the primer composition.

[0027] To facilitate the formation of a uniform primer layer without peeling, the average particle size of the perfluoropolymer powder or pellet is preferably 150 μm or more, and more preferably 200 μm or more. To facilitate the formation of a smooth primer layer, the average particle size of the perfluoropolymer powder or pellet is preferably 500 μm or less, and more preferably 300 μm or less.

[0028] The average particle size of perfluoropolymer powder or pellets is measured using particle analysis software from images of the primer composition observed with an electron microscope. Examples of particle analysis software include SIF's MultiImageTool. Using this method, and employing the elemental identification function of the device, it is also possible to measure the average particle size of only the perfluoropolymer powder or pellets from a primer composition containing both perfluoropolymer powder or pellets and a predetermined powder. The average particle size is the numerical average of the particle sizes of 500 randomly selected particles.

[0029] From the viewpoint of forming a smooth primer layer, the apparent density of the perfluoropolymer powder or pellet is preferably 0.7 g / mL or more, more preferably 0.8 g / mL or more, even more preferably 0.9 g / mL or more, even more preferably 1.0 g / mL or more, and particularly preferably 1.1 g / mL or more. The upper limit of the apparent density of the perfluoropolymer powder or pellet is not particularly limited, but may be, for example, 2.0 g / mL or less. The apparent density is measured in accordance with JIS K6892.

[0030] Perfluoropolymers are preferably molten. Molten perfluoropolymers are easier to process during rotlining by melting them through the heat treatment described later. The moltenness of perfluoropolymers is generally expressed by the melt flow rate (MFR), which is an indicator of their flowability.

[0031] Due to the improved interlayer adhesion resulting from the flow properties of the perfluoropolymer, the MFR of the perfluoropolymer is preferably 0.1 g / 10 min or more, more preferably 1 g / 10 min or more, and even more preferably 5 g / 10 min or more.

[0032] Since the corrosion resistance of the laminate is improved, the MFR of the perfluoropolymer is preferably 50 g / 10 min or less, more preferably 40 g / 10 min or less, and even more preferably 30 g / 10 min or less.

[0033] For example, the MFR of a perfluoropolymer can be adjusted to the above range by adjusting the molecular weight of the perfluoropolymer. MFR is expressed as the weight extruded from a 2 mm diameter nozzle for 10 minutes under a load of 5 kg, according to ASTM D3159. For perfluoropolymers, MFR is measured at 372°C.

[0034] Unlike the topcoat composition described later, the primer composition is applied directly to the substrate, and therefore requires adhesion to the substrate. To improve the adhesion of the perfluoropolymer to the substrate, it is preferable that the perfluoropolymer has functional groups that contribute to improved adhesion to the substrate. Hereinafter, "functional groups that contribute to improved adhesion to the substrate" may be referred to as "specific functional groups." Specific functional groups interact with the substrate surface and contribute to improved adhesion to the substrate. Examples of specific functional groups include the functional groups shown in Table 1 described later.

[0035] To improve the adhesion of perfluoropolymers to the substrate, the perfluoropolymer has a main chain with 1 × 10 carbon atoms. 6 It is preferable that each molecule has 100 or more specific functional groups. To improve the adhesion of the perfluoropolymer to the substrate, the perfluoropolymer has a main chain with 1 × 10 carbon atoms. 6 It is preferable that each individual has 500 or fewer specific functional groups.

[0036] Infrared spectroscopy can be used to identify the types of specific functional groups and to measure the number of specific functional groups.

[0037] The specific number of functional groups is measured by the following method. First, tablets are prepared using perfluoropolymer powder or pellets and KBr, and these tablets are analyzed by Fourier transform infrared spectroscopy. The difference spectrum is obtained between the infrared absorption spectrum of the obtained perfluoropolymer and the base spectrum where the specific functional group is completely fluorinated and no specific functional group is present. From the absorption peak of the specific functional group appearing in this difference spectrum, the number of carbon atoms in the perfluoropolymer (1 × 10⁶) is calculated according to the following formula (A). 6 The number of specific functional groups N per individual is calculated. N = I × K / t (A) I: Absorbance K: Correction coefficient t: Film thickness (mm)

[0038] For reference, Table 1 shows the absorption frequency, molar extinction coefficient, and correction factor of the specific functional group in this disclosure. The molar extinction coefficient was determined from FT-IR measurement data of the low-molecular-weight model compound.

[0039] [Table 1]

[0040] The absorption frequencies of -CH2CF2H, -CH2COF, -CH2COOH, -CH2COOCH3, and -CH2CONH2 are several tens of kaiser (cm) from the absorption frequencies of -CF2H, -COF, -COOHfree, -COOHbonded, -COOCH3, and -CONH2 shown in Table 1, respectively. -1 ) becomes lower. Therefore, for example, the specific functional group number of -COF is lower, and the absorption frequency due to -CF2COF is 1883 cm⁻¹. -1 The number of specific functional groups determined from the absorption peak and the absorption frequency of 1840 cm² due to -CH2COF -1 This is the sum of the number of specific functional groups determined from the absorption peaks.

[0041] The specific functional group may be located at the main chain end or side chain end of the perfluoropolymer, or it may be located within the main chain or side chain of the perfluoropolymer. In this disclosure, it is preferable that the specific functional group is located at the main chain end of the perfluoropolymer. Having the specific functional group at the main chain end allows for efficient improvement of adhesion to the substrate. The number of specific functional groups may be the total number of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and CH2OH.

[0042] In this disclosure, the specific functional group is preferably a carbonyl group-containing group. More preferably, the specific functional group is at least one group selected from the group consisting of a carbonylamide group, a carboxyl group, an acylfluoride group, and a methoxycarbonyl group. From the viewpoint of imparting adhesion, the specific functional group is particularly preferably a carboxyl group and a carbonylamide group.

[0043] Specific functional groups are introduced into perfluoropolymers, for example, by chain transfer agents and / or polymerization initiators used in the production of perfluoropolymers. For example, when an alcohol is used as a chain transfer agent and a peroxide having the structure -CH2OH is used as a polymerization initiator, -CH2OH is introduced to the main chain ends of the perfluoropolymer. Alternatively, specific functional groups may be introduced into perfluoropolymers by polymerizing monomers having the specific functional groups.

[0044] It is preferable that the specific functional group is introduced to the perfluoropolymer terminus by a chain transfer agent and / or polymerization initiator used in the production of the perfluoropolymer. Perfluoropolymers having such a structure exhibit better adhesion to the substrate.

[0045] Specific functional groups may be introduced to the perfluoropolymer ends by chain transfer agents and / or polymerization initiators used in the production of the perfluoropolymer, and then converted to other structures by further reactions. Alternatively, a method may be used in which functional groups are generated at the ends of the main chain by corona treatment of the perfluoropolymer powder or pellets.

[0046] The method for producing the perfluoropolymer used in the primer composition of this disclosure is not particularly limited, and known polymerization methods such as suspension polymerization can be appropriately selected. The obtained perfluoropolymer can be crushed or molded by known methods as needed to form a powder or pellets.

[0047] <Specified powder> The specified powder functions, for example, as a heat stabilizer, thereby suppressing foaming of the laminate that may occur due to the instability of the perfluoropolymer during the heat treatment of rotlining. The specified powder is at least one powder selected from the group consisting of amine-based antioxidants with a molecular weight of 1000 or less and organic sulfur-containing compounds with a molecular weight of 1000 or less. The upper limit of the types of the specified powder is not particularly limited, but for example, it may be one to five types of powders, or one or two types of powders.

[0048] To suppress foaming in the primer layer of the laminate, the content of the predetermined powder is preferably 0.1% by mass or more relative to the total amount of the primer composition. To suppress foaming in the topcoat layer in addition to the primer layer of the laminate, the content of the predetermined powder is more preferably 0.5% by mass or more relative to the total amount of the primer composition. To sufficiently reduce the elution of components of the primer layer, the content of the predetermined powder is preferably 15.0% by mass or less, and more preferably 5.0% by mass or less, relative to the total amount of the primer composition. If the predetermined powder is a plurality of powders, the content of the predetermined powder is the total content of the plurality of powders.

[0049] (Amine-based antioxidants) The amine-based antioxidant used in the primer composition of this disclosure is in powder form. In this disclosure, the amine-based antioxidant means an antioxidant having a structure represented by the chemical formula "-NH-". The amine-based antioxidant may also have a sulfur atom in its molecule. The molecular weight of the amine-based antioxidant is 1000 or less. If the molecular weight of the amine-based antioxidant is 1000 or less, foaming of the laminate can be suitably suppressed. The lower limit of the molecular weight of the amine-based antioxidant is not particularly limited, but for example, it is 100 or more. The molecular weight of the amine-based antioxidant can be determined from the molecular formula of the amine-based antioxidant.

[0050] Examples of amine-based antioxidants with a molecular weight of 1000 or less include aromatic amines having aromatic hydrocarbon groups such as phenyl groups and naphthyl groups in their molecules. Specific examples of amine-based antioxidants with a molecular weight of 1000 or less include phenylenediamine compounds such as N,N'-diphenyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, and reaction products of diphenylamine and diisobutylene; aromatic secondary amine compounds such as dinaphthylamine, phenyl-α-naphthylamine, phenyl-β-naphthylamine, 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine, phenylcyclohexyl-p-phenylenediamine, and styrene-diphenylamine; diphenylamine compounds such as p-(p-toluenesulfonylamide)diphenylamine; and benzotriazole compounds such as benzotriazole, 2-(2-hydroxy-5-methylphenyl)benzotriazole, and 2-(2-hydroxy-5-tetraoctylphenyl)benzotriazole.

[0051] Since foaming of the laminate can be effectively suppressed, phenylenediamine compounds and diphenylamine compounds are preferred as amine-based antioxidants with a molecular weight of 1000 or less, and N,N'-di-2-naphthyl-p-phenylenediamine and p-(p-toluenesulfonylamide)diphenylamine are more preferred.

[0052] Commercially available amine-based antioxidants with a molecular weight of 1000 or less may be used. Examples of such commercially available products include Nocrack White and Nocrack TD, both manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0053] (Organic sulfur-containing compounds) The organic sulfur-containing compound used in the primer composition of this disclosure is in powder form. The molecular weight of the organic sulfur-containing compound is 1000 or less. If the molecular weight of the organic sulfur-containing compound is 1000 or less, foaming of the laminate can be suitably suppressed. The lower limit of the molecular weight of the organic sulfur-containing compound is not particularly limited, but for example, it is 100 or more. The molecular weight of the organic sulfur-containing compound can be determined from the molecular formula of the organic sulfur-containing compound. Note that amine-based antioxidants having a sulfur atom are exemplified in the above-mentioned amine-based antioxidants. In this disclosure, the organic sulfur-containing compound is a compound excluding amine-based antioxidants having a sulfur atom.

[0054] Specific examples of organic sulfur-containing compounds with a molecular weight of 1000 or less include mercaptobenzimidazole compounds such as 2-mercaptobenzimidazole and 2-mercaptomethylbenzimidazole; 2-mercaptobenzothiazole, cyclohexylamine salts of 2-mercaptobenzothiazole, dibenzothiadyl disulfide, 2-(N,N'-diethylthiocarbamoylthio)benzothiazole, 2-(4'-morpholinodithio)benzothiazole, N-cyclohexyl-2-benzothiazolyl sulfenamide, N-oxydiethylene-2-benzothiazolyl sulfenamide, N-tert-butyl-2-benzothiazolyl sulfenamide, N,N'-dicyclohexyl-2-benzothiazolyl sulfenamide, and N,N'-diisopropylbenzothiazole Examples include mercaptobenzothiazole compounds such as 2-2-sulfen; mercaptoimidazoline compounds such as 2-mercaptoimidazoline; dithiocarbamates such as pentamethylenedithiocarbamic acid, pipecholyldithiocarbamic acid, dimethyldithiocarbamic acid, diethyldithiocarbamic acid, dibutyldithiocarbamic acid, and N-ethyl-N-phenyldithiocarbamic acid; thiourea derivatives such as thiourea, N,N'-diethylthiourea, N,N'-dibutylthiourea, dilaurylthiourea, and N,N'-diphenylthiourea; and thiram compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, and dipentamethylenethiuram tetrasulfide. These organic sulfur-containing compounds may be, for example, metal salts such as Zn, Sn, Cd, Cu, and Fe; or organic salts such as piperidine salts and pipecholyl salts.

[0055] Since foaming of the laminate can be effectively suppressed, preferred organic sulfur-containing compounds with a molecular weight of 1000 or less include mercaptobenzothiazole compounds, their metal salts, and their organic salts, with zinc salts of 2-mercaptobenzothiazole being more preferred.

[0056] Commercially available organic sulfur-containing compounds with a molecular weight of 1000 or less may be used. Examples of such commercially available products include Noxellar MZ manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0057] <Other primer ingredients> The primer composition of this disclosure may contain only a perfluoropolymer and a predetermined powder. However, the primer composition of this disclosure may further contain components other than the perfluoropolymer and the predetermined powder (hereinafter sometimes referred to as "other primer components") as needed, to the extent that they do not impair the effects of this disclosure. The other primer components are not particularly limited, and components commonly used in primers for paints can be used. Examples of other primer components include pigments, anti-aging agents, leveling agents, solid lubricants, water absorbers, surface modifiers, UV absorbers, light stabilizers, plasticizers, color separation inhibitors, scratch inhibitors, antifungal agents, antibacterial agents, antioxidants, antistatic agents, silane coupling agents, etc. In order to suppress film shrinkage, the primer composition may contain fillers as other primer components. The other primer components may be added independently of the perfluoropolymer, or they may be added integrated with the perfluoropolymer, such as by being kneaded into the perfluoropolymer. When other primer components are used, the content of the other primer components is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and most preferably 1% by mass or less, based on the total amount of the primer composition.

[0058] To suppress foaming of the laminate, the primer composition of this disclosure preferably does not contain any heat stabilizers other than the specified powder. Examples of heat stabilizers other than the specified powder include metal powders, which will be described later.

[0059] To suppress foaming in the topcoat layer of the laminate, the primer composition of this disclosure preferably does not contain metal powder. Examples of metals that can be used as metal powder include elemental metals such as Mn, Fe, Ni, Co, Cu, Zn, Mo, Pd, Ag, Cd, Sn, and Ba; alloys such as Zn / Cu (brass) and Cu / Sn (bronze); and metal oxides such as CuO.

[0060] To suppress foaming in the primer layer of the laminate, the primer composition of this disclosure preferably does not contain a binder resin. Examples of binder resins include nitrogen-containing polymers such as polyamide, polyimide, polyamideimide, and polyetherimide; sulfur-containing polymers such as polyphenylene sulfide, polyarylene sulfide, and polyethersulfone; polyetheretherketone; and polyphenylene carbonate. Nitrogen-containing polymers are, for example, polymers having one or both of amide and imide bonds. By not including a binder resin with a different melting point from the perfluoropolymer in the primer composition, melting unevenness of the primer composition is sufficiently reduced when heat-treated by rotlining, and a uniform primer layer can be easily formed.

[0061] <Method for producing primer composition> The primer compositions of this disclosure are manufactured by mixing raw materials, for example, by known methods. For example, a primer composition can be manufactured by mixing a perfluoropolymer, a predetermined powder, and other primer components added as needed, using a mixer. The mixer is not particularly limited, but for example, a V-type blender, a Henschel mixer, etc., can be used. The predetermined powder may be added separately from the perfluoropolymer, or it may be added integrated with the perfluoropolymer, such as by being kneaded into the perfluoropolymer.

[0062] [Laminated structure] This disclosure also relates to a laminate comprising a first layer which is a ro-lining film formed from the primer composition of this disclosure described above. The laminate of this disclosure comprises a first layer and a second layer. The first layer is the substrate-side layer. The laminate of this disclosure may further comprise a substrate. If the laminate comprises a substrate, the first layer is provided on the substrate. The second layer is provided on the first layer. Hereinafter, the "first layer" may be referred to as the "primer layer" and the "second layer" as the "topcoat layer". The primer layer is a layer provided on the substrate side of the topcoat layer.

[0063] The primer composition of this disclosure suppresses foaming of the laminate while also exhibiting excellent adhesion to the substrate. Therefore, it is preferable that a primer layer, which is a rotlining film formed from the primer composition of this disclosure, be provided directly on the substrate.

[0064] <Base material> The substrate is not particularly limited and can include, for example, elemental metals such as iron, aluminum, copper, and nickel; alloys such as stainless steel (SUS); and non-metallic inorganic materials such as enamel, glass, and ceramics. The shape of the substrate is not particularly limited, but for example, it can be tubular. When a tubular substrate is used, a resin film can be easily formed inside the substrate while rotating the tubular substrate by rotrinizing.

[0065] <Primer layer> The primer layer is a ro-lining film formed from the primer composition of this disclosure described above. The thickness of the primer layer may be appropriately selected considering factors such as the difficulty of peeling the primer layer from the substrate. From the viewpoint of uniformly forming the primer layer and improving the corrosion resistance and chemical resistance of the laminate, the thickness of the primer layer is preferably 100 μm or more, more preferably 300 μm or more, and even more preferably 500 μm. From the viewpoint of good adhesion between the substrate and the primer layer and suppressing peeling of the primer layer from the substrate, the thickness of the primer layer is preferably 10,000 μm or less, more preferably 8,000 μm or less, even more preferably 6,000 μm or less, even more preferably 3,000 μm or less, and particularly preferably 1,500 μm or less. The thickness of the primer layer is measured using a magnetic / eddy current film thickness gauge.

[0066] To maintain an appropriate amount of heat stabilizers and other components in the primer layer and reduce component elution, the content of perfluoropolymer powder or pellets in the primer layer is preferably 85.0% by mass or more, and more preferably 95.0% by mass or more, relative to the total amount of the primer layer. To ensure a sufficient amount of heat stabilizers and other components in the primer layer and effectively suppress foaming in the primer layer, the content of perfluoropolymer powder or pellets in the primer layer is preferably 99.5% by mass or less, relative to the total amount of the primer layer.

[0067] <Top coat layer> The topcoat layer is, for example, a ro-lining film formed from a topcoat composition. The thickness of the topcoat layer can be appropriately selected considering the application and other factors. From the viewpoint of uniformly forming the topcoat layer and improving the corrosion resistance and chemical resistance of the laminate, the thickness of the topcoat layer is preferably 100 μm or more, more preferably 300 μm or more, even more preferably 500 μm or more, even more preferably 1000 μm or more, and particularly preferably more than 1500 μm. To obtain good physical properties, the thickness of the topcoat is preferably 10000 μm or less, more preferably 8000 μm or less, even more preferably 6000 μm or less, and even more preferably 3000 μm or less. The thickness of the topcoat layer is measured using a magnetic / eddy current thickness gauge.

[0068] The topcoat composition is not particularly limited, but for example, it is a powder composition containing a fluororesin. Preferably, the topcoat composition contains a perfluoropolymer powder or pellets. Examples of perfluoropolymers used in the topcoat composition include those similar to those used in the primer composition. The topcoat layer is preferably a rotlining film formed from perfluoropolymer powder or pellets.

[0069] The perfluoropolymer powder or pellets contained in the topcoat composition may be different from the perfluoropolymer powder or pellets contained in the primer composition. However, in order to ensure good adhesion between the primer layer and the topcoat layer, it is preferable that the perfluoropolymer powder or pellets contained in the topcoat composition be the same as those contained in the primer composition.

[0070] The topcoat composition may contain only a perfluoropolymer. However, the topcoat composition may also contain other components (hereinafter sometimes referred to as "other topcoat components") as needed, provided that they do not impair the effects of the present disclosure. Examples of other topcoat components include those similar to other primer components. The topcoat composition may also contain either or both an inorganic filler and carbon black, provided that they do not impair the chemical resistance and corrosion resistance of the laminate.

[0071] To sufficiently reduce the elution of other topcoat components, the perfluoropolymer content in the topcoat layer is preferably 99% by mass or more, more preferably 99.5% by mass or more, even more preferably 99.6% by mass or more, even more preferably 99.7% by mass or more, even more preferably 99.8% by mass or more, still more preferably 99.9% by mass or more, particularly preferably 99.99% by mass or more, and most preferably 99.999% by mass or more, based on the total amount of the topcoat layer. The upper limit for the perfluoropolymer content in the topcoat layer is 100.0% by mass, based on the total amount of the topcoat layer.

[0072] It is preferable that the topcoat composition and the topcoat layer formed from the topcoat composition do not contain a heat stabilizer. For example, there is a method of suppressing foaming of the laminate by including a heat stabilizer in the topcoat layer formed by rotlining. However, since the primer composition of this disclosure can suppress foaming of the laminate, foaming of the laminate can be suitably suppressed even if the topcoat layer does not contain a heat stabilizer. In addition, by not including a heat stabilizer in the topcoat layer, the advantages of reducing discoloration of the film due to the heat stabilizer and the advantage of not leaching of heat stabilizer components can be obtained. Examples of heat stabilizers include amine-based antioxidants, organic sulfur-containing compounds, and metal powders. Examples of amine-based antioxidants include those similar to those exemplified as amine-based antioxidants with a molecular weight of 1000 or less used in the primer composition. Examples of organic sulfur-containing compounds include those similar to those exemplified as organic sulfur-containing compounds with a molecular weight of 1000 or less used in the primer composition. Examples of metal powders include those similar to those exemplified as metal powders that are preferably not included in the primer composition. To sufficiently reduce the amount of other topcoat components leached out, it is preferable that the topcoat composition and the topcoat layer formed from the topcoat composition do not contain the specified powder.

[0073] To sufficiently reduce the amount of other topcoat components leached out, it is preferable that the topcoat composition and the topcoat layer formed from the topcoat composition do not contain at least one of the binder resin, filler, and inorganic powder. Examples of binder resins include those similar to those exemplified as binder resins that are preferably not included in the primer composition. Examples of fillers include glass fiber. Examples of inorganic powders include glass powder and silicon powder.

[0074] It is preferable that the topcoat composition and the topcoat layer formed from the topcoat composition do not contain pigments. For example, there is a method of adjusting the film color tone derived from the heat stabilizer by including a pigment in the topcoat layer formed by rotlining. However, since the primer composition of this disclosure can suppress foaming of the laminate, the addition of a heat stabilizer to the topcoat layer can be omitted, and consequently, the addition of a pigment can also be omitted. By not including a pigment in the topcoat layer, the advantage of not having pigment components leach out can be obtained.

[0075] <Method for manufacturing laminates> This disclosure also relates to a method for manufacturing the laminate of the present disclosure described above. The method for manufacturing the laminate of the present disclosure includes a first layer formation step and a second layer formation step.

[0076] (1st layer formation process) In the first layer formation step, a primer layer is formed on the substrate. In the first layer formation step, a primer layer is formed from the primer composition of the present disclosure as described above by rotlining. More specifically, the primer composition of the present disclosure is placed in a tubular substrate, and the primer composition inside the substrate is heat-treated (e.g., fired) while the substrate is rotated to form a primer layer on the inner surface of the substrate. In order to melt the perfluoropolymer contained in the primer composition and perform good processing, the heating temperature in this step is preferably 250 to 400°C. For the same reason, the heating time is preferably 10 to 300 minutes.

[0077] (Second layer formation process) In the second layer formation step, a topcoat layer is formed on the primer layer. In the second layer formation step, a topcoat layer is formed by rotlining, for example, from a topcoat composition. More specifically, a topcoat composition is placed inside a tubular substrate on which a primer layer has been formed, and the topcoat composition inside the substrate is heated while the tubular substrate is rotated to form a topcoat layer on the primer layer (more specifically, on the side of the primer layer that is not adhered to the substrate). In order to melt the topcoat composition and perform good processing, the heating temperature in this step is preferably 250 to 400°C. For the same reason, the heating time is preferably 10 to 300 minutes.

[0078] [Goods] This disclosure also relates to articles having the laminate described above. The articles are not particularly limited and include, for example, chemical containers, tanks, piping, fittings, valves, pipes, ducts, etc. The articles of this disclosure are particularly suitable for use in fields where the elution of components contained in the primer layer and topcoat layer is undesirable. Such fields include, for example, semiconductor manufacturing fields such as semiconductor manufacturing equipment, semiconductor chemical manufacturing equipment, and semiconductor chemical containers; medical fields such as pharmaceutical manufacturing equipment and pharmaceutical containers; chemical fields such as chemical manufacturing equipment and chemical containers; food fields such as alcohol brewing containers, fermented food brewing containers, and fermented food storage containers; and steel manufacturing fields such as steel plants.

[0079] While embodiments of this disclosure have been described above, it will be understood that a variety of modifications to the form and details are possible without departing from the spirit and scope of the claims. [Examples]

[0080] The present disclosure will be specifically explained below with reference to examples, but the present disclosure is not limited to these examples. Unless otherwise specified in the following examples, "parts" and "%" refer to "parts by mass" and "% by mass," respectively.

[0081] The components used in the following examples are as follows: Perfluoropolymer A: TFE / PEVE = 95 / 5 mol% (MFR: 8 g / 10 min, average particle size: 162 μm, apparent density: 1.0 g / mL, number of main chain carbons per unit: 1×10 6 number of specific functional groups per unit: 245) Perfluoropolymer B: TFE / PPVE = 98 / 2 mol% (MFR: 6 g / 10 min, average particle size: 213 μm, apparent density: 1.1 g / mL, number of main chain carbons per unit: 1×10 6 number of specific functional groups per unit: 211) Perfluoropolymer C: TFE / HFP = 91 / 9 mol% (MFR: 5 g / 10 min, average particle size: 246 μm, apparent density: 0.7 g / mL, number of main chain carbons per unit: 1×10 6 number of specific functional groups per unit: 147) Perfluoropolymer D: TFE / HFP / PPVE = 85 / 13 / 2 mol% (MFR: 10 g / 10 min, average particle size: 151 μm, apparent density: 0.8 g / mL, number of main chain carbons per unit: 1×10 6 [[ID=!4]]number of specific functional groups per unit: 314) Amine antioxidant P: Nocrack White manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. (Compound name: N,N'-di-2-naphthyl-p-phenylenediamine, molecular weight: 360) Organic sulfur-containing compound: Noceller MZ manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. (Compound name: zinc salt of 2-mercaptobenzothiazole, molecular weight: 397) Amine antioxidant Q: Nocrack TD manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. (Compound name: p-(p-toluenesulfonylamide)diphenylamine, molecular weight: 338) Metal powder R: Zinc powder manufactured by Kishida Chemical Co., Ltd. Metal powder S: Iron powder manufactured by Kishida Chemical Co., Ltd. Polyamideimide: Torlon PAI manufactured by Solvay Polyphenylene sulfide: Ryton PPS manufactured by Solvay

[0082] [Preparation of primer composition] The raw material powders were mixed in the compositions shown in Tables 2 to 5 to obtain the primer compositions of Examples 1 to 23 and Comparative Examples 1 to 9.

[0083] [Formation of the primer layer] The inner surface of a 1L mold was blast-treated using alumina powder (Tosa Emery #40, manufactured by Uji Denki Kagaku Kogyo Co., Ltd.) at a spraying pressure of 1.0 MPa. The blast-treated mold was then filled with the primer compositions shown in Tables 2 to 5 in an amount that would achieve the target film thickness shown in Tables 2 to 5, and heated at 380°C for 60 minutes using a rotlining molding machine. In this way, a primer layer was formed on the inner surface of the mold.

[0084] [Formation of the top coat layer] In the mold on which the primer layer was formed, the topcoat composition was sealed in an amount that would yield a film thickness of 2000 μm, and the mold was heated at 350°C for 90 minutes using a rotlining molding machine. In this way, a topcoat layer was formed on the primer layer formed on the inner surface of the mold, and a rotlining laminate was obtained. As the topcoat composition, either AC-5820 (pure PFA powder) or AC-5830 (a mixture of PFA powder, an amine-based antioxidant, and an organic sulfur-containing compound) manufactured by Daikin Industries, Ltd., as shown in Tables 2 to 5, was used.

[0085] [Evaluation Method] <Adhesion of the primer layer> After the primer layer was formed and before the topcoat layer was formed, the primer layer formed on the inner surface of the mold was observed to check for the presence or absence of foaming in the primer layer and the presence or absence of peeling (film delamination) of the primer layer. The adhesion between the primer layer and the mold was evaluated from the following perspectives. "Foaming present" and "B" were judged as failures, and "A" was judged as a pass. Foaming present: Foaming is present in the primer layer. B: Partial peeling of the coating present. A: No peeling of the coating was observed.

[0086] <State of the Rotrining laminate> The appearance of the rotlining laminate obtained above (more specifically, the appearance of the topcoat layer) was observed and evaluated from the following perspectives. "C" and "B" were judged as unacceptable, and "A" was judged as acceptable. C: Numerous foams in a rotrining laminate B: Slightly foamed Rotrining laminate A: No foaming of the Rotrining laminate

[0087] <Amount of extract from rotrining laminate> Of the rotlining laminates obtained above, the extract amounts were measured for three representative rotlining laminates (rotlining laminates formed using the primer compositions of Example 5, Example 6, and Example 15). A 3.5% HCl aqueous solution was placed in the containers of the three rotlining laminates and left to stand at 25°C for 7 days. Subsequently, the total extract amounts of 17 elements (Ag, Al, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Ti, Zn) were measured by inductively coupled plasma emission spectrometry. Note that these extract amounts mainly correspond to the elution amounts of components from the primer layer and topcoat layer.

[0088] The evaluation results are shown in Tables 2 to 5. In Tables 2 to 5, a "-" in the Primer Composition column indicates that the corresponding component was not added. In Tables 2 to 5, a "-" in the Topcoat Composition column and the Condition of the Rotolining Laminate column indicates that foaming was observed in the primer layer, and therefore the topcoat layer was not formed. In Tables 2 to 5, a "-" in the Extract Amount from the Rotolining Laminate column indicates that the extract was not measured.

[0089] [Table 2]

[0090] [Table 3]

[0091] [Table 4]

[0092] [Table 5]

[0093] From the evaluation results above, it became clear that the primer composition of this disclosure can suppress foaming of the laminate when used to form the primer layer of the laminate. [Industrial applicability]

[0094] The disclosed primer composition can be suitably used as a primer when coating fluororesins by rotlining.

Claims

1. A primer composition for rotlining, Perfluoropolymer powder or pellets, A predetermined powder selected from the group consisting of an amine-based antioxidant with a molecular weight of 1000 or less and an organic sulfur-containing compound with a molecular weight of 1000 or less. A primer composition characterized by containing the following:

2. The primer composition according to claim 1, wherein the perfluoropolymer is a copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether), a copolymer of tetrafluoroethylene and hexafluoropropylene, or a copolymer of tetrafluoroethylene, hexafluoropropylene, and perfluoro(alkyl vinyl ether).

3. The primer composition according to claim 1 or 2, wherein the content of the perfluoropolymer powder or pellets is 95.0% by mass or more and 99.5% by mass or less, based on the total amount of the primer composition.

4. The primer composition according to claim 1 or 2, wherein the content of the predetermined powder is 0.5% by mass or more and 5.0% by mass or less, based on the total amount of the primer composition.

5. The primer composition according to claim 1 or 2, wherein the average particle size of the perfluoropolymer powder or pellets is 150 μm or more and 500 μm or less.

6. The primer composition according to claim 1 or 2, wherein the apparent density of the perfluoropolymer powder or pellets is 0.7 g / mL or more.

7. A primer composition according to claim 1 or 2, which does not contain metal powder.

8. A primer composition according to claim 1 or 2, which does not contain nitrogen-containing polymers and sulfur-containing polymers.

9. The perfluoropolymer is a copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether), a copolymer of tetrafluoroethylene and hexafluoropropylene, or a copolymer of tetrafluoroethylene, hexafluoropropylene, and perfluoro(alkyl vinyl ether). The content of the perfluoropolymer powder or pellets is 95.0% by mass or more and 99.5% by mass or less, based on the total amount of the primer composition. The amine-based antioxidant is a phenylenediamine compound or a diphenylamine compound. The aforementioned organic sulfur-containing compound is a mercaptobenzothiazole compound or a metal salt thereof. The primer composition according to claim 1 or 2, wherein the content of the predetermined powder is 0.5% by mass or more and 5.0% by mass or less, based on the total amount of the primer composition.

10. A laminate comprising a first layer which is a substrate layer and a second layer provided on the first layer, A laminate in which the first layer is a rotlining film formed from the primer composition described in claim 1 or 2.

11. The second layer is a rotlining film formed from the powder or pellets of the perfluoropolymer, The laminate according to claim 10, wherein the second layer does not contain an amine-based antioxidant, an organic sulfur-containing compound, and a metal powder.

12. The second layer is a rotlining film formed from the powder or pellets of the perfluoropolymer, The laminate according to claim 10, wherein the content of the perfluoropolymer in the second layer is 99% by mass or more with respect to the total amount of the second layer.

13. The laminate according to claim 10, wherein the thickness of the first layer is 300 μm or more.

14. An article having the laminate described in claim 10.

15. A first layer formation step in which a first layer is formed on a substrate, A method for manufacturing a laminate, comprising a second layer forming step of forming a second layer on the first layer, A method for producing a laminate, comprising forming the first layer from the primer composition described in claim 1 or 2 by rotlining in the first layer formation step.

16. The method for manufacturing a laminate according to claim 15, wherein the second layer is formed by rotlining in the second layer formation step.

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