Primer composition, laminate, article, and method for producing laminate

Abstract

[Problem] The present disclosure provides a primer composition capable of suppressing foaming of a laminate when used to form a primer layer of the laminate. [Solution] A primer composition for rotary liners, which is characterized by containing a powder or pellet of a perfluoropolymer and at least one prescribed powder selected from the group consisting of amine antioxidants having a molecular weight of 1000 or less and organic sulfur-containing compounds having 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 comprising a hot-melt fluororesin is added to a cylindrical article to be lined, the cylindrical article is rotated, and the centrifugal force generated by the rotation is used to uniformly press the powder onto the article to be lined, and heating is performed to melt the hot-melt fluororesin onto the surface of the article to be lined. Patent Document 2 discloses the incorporation of metal powder into the fluororesin to suppress the generation of bubbles. Patent Document 3 discloses a composition using a metal powder comprising non-bubble-promoting metal powder.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2000-237682

[0006] Patent Document 2: Japanese Patent Application Publication No. 4-267744

[0007] Patent Document 3: Japanese Patent Publication No. 2006-509095 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The purpose of this disclosure is to provide a primer composition that can suppress foaming of the laminate when used as a primer layer to form a laminate.

[0010] Methods for solving problems

[0011] This disclosure relates to a primer composition for use with a rotary liner, characterized in that the primer composition comprises a powder or granules of a perfluoropolymer and at least one specified powder selected from the group consisting of an amine antioxidant with a molecular weight of less than 1000 and an organic sulfur-containing compound with a molecular weight of less than 1000.

[0012] 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).

[0013] Preferably, the content of the perfluoropolymer powder or granules is 95.0% by mass or more and 99.5% by mass or less relative to the total amount of the primer composition.

[0014] Preferably, the content of the specified powder is 0.5% by mass or more and 5.0% by mass or less relative to the total amount of the primer composition.

[0015] Preferably, the average particle size of the perfluoropolymer powder or granules is 150 μm or more and 500 μm or less.

[0016] Preferably, the apparent density of the perfluoropolymer powder or granules is 0.7 g / mL or higher.

[0017] Preferably, the primer composition does not contain metal powder.

[0018] Preferably, the primer composition does not contain nitrogen-containing polymers or sulfur-containing polymers.

[0019] 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).

[0020] The content of the perfluoropolymer powder or granules is 95.0% by mass or more and 99.5% by mass or less relative to the total amount of the primer composition.

[0021] The amine-based antioxidant is a phenylenediamine compound or a diphenylamine compound.

[0022] The organic sulfur-containing compound is a mercaptobenzothiazole compound or its metal salt.

[0023] The content of the specified powder is 0.5% by mass or more and 5.0% by mass or less relative to the total amount of the primer composition.

[0024] This disclosure also relates to a laminate having a first layer as a substrate side layer and a second layer disposed on the first layer, wherein the first layer is a rotary liner film formed by the primer composition.

[0025] Preferably, the second layer is a rotary inner liner film formed from the powder or granules of the perfluoropolymer, and the second layer does not contain amine antioxidants, organic sulfur compounds, or metal powders.

[0026] Preferably, the second layer is a rotary inner liner film formed from the powder or granules of the perfluoropolymer, and the content of the perfluoropolymer in the second layer is 99% by mass or more relative to the total amount of the second layer.

[0027] Preferably, the thickness of the first layer is 300 μm or more.

[0028] This disclosure also relates to an article having the aforementioned laminate.

[0029] This disclosure also relates to a method for manufacturing a laminate, comprising: a first layer forming step of forming a first layer on a substrate, and a second layer forming step of forming a second layer on the first layer, wherein, in the first layer forming step, the first layer is formed from the primer composition using a rotating inner liner.

[0030] Preferably, in the second layer forming process, the second layer is formed using a rotating inner liner.

[0031] Invention Effects

[0032] The primer composition disclosed herein can suppress foaming of the laminate when used as a primer layer to form a laminate. Detailed Implementation

[0033] The following provides a detailed description of this disclosure.

[0034] [Primer Composition]

[0035] The primer composition disclosed herein is a composition for rotary liners. In this disclosure, a rotary liner refers to a coating method utilizing rotational forming.

[0036] The primer composition disclosed herein is used to form a primer layer. The primer layer is disposed between the substrate and the topcoat layer, improving the adhesion between the substrate and the topcoat layer.

[0037] When applying a rotary liner coating using fluororesin powder, foaming due to the thermal decomposition of the fluororesin occurs during heat treatment. To suppress foaming, it is known to add metal powder to the fluororesin powder. However, when the primer layer contains metal powder, residual foaming occurs in the laminate (particularly the topcoat). Therefore, the primer composition of this disclosure comprises at least one specified powder selected from the group consisting of an amine antioxidant with a molecular weight of 1000 or less and an organic sulfur-containing compound with a molecular weight of 1000 or less. By including such a specified powder in the primer layer, the problem of residual foaming in the topcoat can be solved not only in the primer layer but also in the topcoat. Thus, the primer composition of this disclosure, when used as a primer layer to form a laminate, can suppress foaming in the primer layer of the laminate, and consequently, also suppress foaming in the topcoat.

[0038] The primer composition disclosed herein comprises a perfluoropolymer powder or granules and a specified powder. In this disclosure, "specified powder" is defined as at least one powder selected from the group consisting of amine 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 disclosed herein is in powder form, granule form, or a mixture of powder and granules. The perfluoropolymer and specified powder contained in the primer composition of this disclosure will be described below.

[0039] <Perfluoropolymers>

[0040] The perfluoropolymers used in this disclosure are in powder or granule 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 PAVEs include perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether) [PEVE], and perfluoro(propyl vinyl ether) [PPVE]. It should be noted that the main chain of the perfluoro monomer consists of carbon atoms, fluorine atoms, and, depending on the case, oxygen atoms (e.g., ether oxygen atoms), and does not have CH or CH2. Furthermore, when using monomer components of multiple perfluoropolymers, there is no particular limit to the upper limit of the number of monomer components; for example, it can be 10, 5, or 3.

[0041] The perfluoropolymers used in this disclosure can be obtained by polymerization using only perfluoro monomers as monomer components. However, the perfluoropolymers used in this disclosure can also be obtained by polymerization using one or more of the aforementioned perfluoro monomers and one or more comonomers as monomer components. The comonomer is a monomer capable of copolymerizing with the perfluoro monomer. Examples of comonomers include, for example, vinyl chloride monomers such as trifluorochloroethylene; vinyl fluoride monomers such as vinylidene fluoride and trifluoroethylene; and monomers having carbonyl groups. Examples of monomers having carbonyl groups include, for example, cyclic monomers having anhydride residues, monomers having carboxyl groups, vinyl esters, and (meth)acrylates. Examples of cyclic monomers having anhydride residues include, for example, itaconic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, and maleic anhydride. When using comonomers, there is no particular limitation on the content of comonomers as long as the perfluorinated monomer is the main component. The total amount of monomer components relative to the perfluorinated polymer can be, for example, less than 30 mol%, less than 10 mol%, less than 5 mol%, or less than 1 mol%.

[0042] Because the resulting coating exhibits high heat and chemical resistance and is suitable for protecting the substrate, perfluoropolymers copolymerized from TFE are preferred. For the same reason, perfluoropolymers are more preferably copolymers of TFE and PAVE [PFA], copolymers of TFE and HFP [FEP], or copolymers of TFE, HFP, and PAVE. The primer composition may contain only one of these copolymers, or it may contain two or more (e.g., two or three).

[0043] As for the perfluoropolymer copolymerized using TFE, copolymers in which the content of TFE units relative to the total amount of monomer units in the perfluoropolymer is preferably 75 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, and still more preferably 95 mol% or more. There is no particular upper limit to the content of TFE units; for example, it can be 99.9 mol% or 99 mol%. The more TFE units there are, the more likely the heat resistance and chemical resistance of the formed coating will be improved. On the other hand, the fewer TFE units there are, the easier the perfluoropolymer is to melt, and the better its moldability will be.

[0044] As the aforementioned PFA, a copolymer with a TFE unit to PAVE unit molar ratio (TFE unit / PAVE unit) of 70 / 30 to 99.9 / 0.1 is preferred, more preferably a copolymer with a TFE unit to PAVE unit molar ratio (TFE unit / PAVE unit) of 80 / 20 to 99.5 / 0.5, even more preferably a copolymer with a TFE unit to PAVE unit molar ratio of 90 / 10 to 99 / 1, and even more preferably a copolymer with a TFE unit to PAVE unit molar ratio of 95 / 5 to 98.5 / 1.5. The more TFE units there are, the higher the heat resistance and chemical resistance of the resulting coating tends to be. On the other hand, the fewer TFE units there are, the easier the PFA is to melt, and the better its moldability tends to be.

[0045] As the aforementioned FEP, a copolymer with a TFE unit to HFP unit molar ratio (TFE unit / HFP unit) of 70 / 30 to 99 / 1 is preferred, more preferably a copolymer with a TFE unit to HFP unit molar ratio (TFE unit / HFP unit) of 80 / 20 to 95 / 5, and even more preferably a copolymer with a TFE unit to HFP unit molar ratio of 85 / 15 to 93 / 7. The more TFE units there are, the more likely the heat resistance and chemical resistance of the formed film tend to be improved. On the other hand, the fewer TFE units there are, the easier the FEP is to melt, and the more likely it is to be moldable.

[0046] As copolymers of the aforementioned TFE, HFP, and PAVE, copolymers with a total TFE and HFP unit to PAVE unit molar ratio (total TFE and HFP units / PAVE units) of 99.9 / 0.1 to 90 / 10 are preferred, and copolymers with a ratio of 99 / 1 to 95 / 5 are 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.

[0047] From the perspective of maintaining an appropriate amount of heat stabilizers and other components contained in the primer layer and sufficiently reducing the leaching of these components, the content of perfluoropolymer powder or granules relative to the total amount of the primer composition is preferably 85.0% by mass or more, and more preferably 95.0% by mass or more.

[0048] From the perspective of ensuring sufficient amounts of heat stabilizers and other components contained in the primer layer and appropriately suppressing foaming in the primer layer, the content of perfluoropolymer powder or granules is preferably 99.5% by mass or less relative to the total amount of the primer composition.

[0049] From the viewpoint of easily forming a uniform primer layer without peeling, the average particle size of the perfluoropolymer powder or granules is preferably 150 μm or more, more preferably 200 μm or more. From the viewpoint of easily forming a smooth primer layer, the average particle size of the perfluoropolymer powder or granules is preferably 500 μm or less, more preferably 300 μm or less.

[0050] The average particle size of the perfluoropolymer powder or granules is a value determined using particle analysis software from an image of the primer composition observed with an electron microscope. Examples of particle analysis software include SIF's MultiImageTool. In this method, by utilizing the element identification function of the device, it is also possible to determine only the average particle size of the perfluoropolymer powder or granules from a primer composition containing both perfluoropolymer powder or granules and a specified powder. The average particle size is the numerical average of the particle sizes of 500 randomly selected particles.

[0051] From the viewpoint of forming a smooth primer layer, the apparent density of the perfluoropolymer powder or granules 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. There is no particular upper limit to the apparent density of the perfluoropolymer powder or granules; for example, it can be 2.0 g / mL or less. Apparent density is determined according to JIS K6892.

[0052] Perfluoropolymers are preferably molten. If molten, the perfluoropolymer can be easily melted and processed during the rotational lining process via the heat treatment described later. The moltenness of perfluoropolymers is usually expressed by the melt flow rate (MFR), which is an indicator of their fluidity.

[0053] From the perspective that the interlayer adhesion is improved due to the flow characteristics 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.

[0054] From the perspective of improving the corrosion resistance of the laminate, the MFR of the perfluoropolymer is preferably 50g / 10min or less, more preferably 40g / 10min or less, and even more preferably 30g / 10min or less.

[0055] For example, the molecular weight ratio (MFR) of a perfluoropolymer can be adjusted to the range described above by changing its molecular weight. MFR, according to ASTM D 3159, is expressed as the weight of material extruded from a 2 mm diameter nozzle under a 5 kg load for 10 minutes. In the case of perfluoropolymers, MFR is measured at 372 °C.

[0056] Unlike the topcoat composition described later, the primer composition is applied directly to the substrate, therefore, good adhesion to the substrate is required. To improve the adhesion of the perfluoropolymer to the substrate, the perfluoropolymer preferably has functional groups that contribute to improving adhesion. Hereinafter, "functional groups that contribute to improving adhesion to the substrate" will sometimes be referred to as "specific functional groups." Specific functional groups interact with the substrate surface, contributing to improved adhesion. Examples of specific functional groups include those shown in Table 1, described later.

[0057] To improve the adhesion of perfluoropolymers to the substrate, it is preferable that the perfluoropolymer has a specific adhesion per 1×10⁻⁶ units. 6 Each main chain carbon atom has more than 100 specific functional groups. To improve the adhesion of perfluoropolymers to substrates, it is preferable that each perfluoropolymer has 1×10⁻⁶ carbon atoms per 10⁻⁶ carbon atom group. 6 Each main chain carbon atom has fewer than 500 specific functional groups.

[0058] Infrared spectroscopy can be used to identify the types of specific functional groups and to determine the number of specific functional groups.

[0059] Specifically, the number of specific functional groups is determined using the following method. First, tablets are prepared using perfluoropolymer powder or granules and KBr, and the tablets are analyzed by Fourier transform infrared spectroscopy. A differential spectrum is obtained between the infrared absorption spectrum of the resulting perfluoropolymer and the background spectrum of a fully fluorinated product without specific functional groups. The number of specific functional groups per 1 × 10⁻⁶ functional groups in the perfluoropolymer is calculated from the absorption peaks of these differential spectra using the following formula (A). 6 The number of specific functional groups N per carbon atom.

[0060] N = I × K / t(A)

[0061] I: Absorbance

[0062] K: Correction coefficient

[0063] t: Membrane thickness (mm)

[0064] For reference, the absorption frequencies, molar absorptivity, and correction factors for specific functional groups in this disclosure are shown in Table 1. The molar absorptivity was determined from FT-IR measurements of low-molecular-weight model compounds.

[0065] [Table 1]

[0066]

[0067] It should be noted that the absorption frequencies of -CH2CF2H, -CH2COF, -CH2COOH, -CH2COOCH3, and -CH2CONH2 are tens of Kaiser (cm) lower than those of -CF2H, -COF, free -COOH, and bonded -COOH, -COOCH3, and -CONH2, respectively, as shown in Table 1. -1 Therefore, for example, the specific number of functional groups in -COF is derived from the absorption frequency of 1883 cm⁻¹ originating from -CF₂COF. -1 The number of specific functional groups determined from the absorption peak at 1840 cm⁻¹ and the absorption frequency originating from -CH₂COF were also analyzed. -1 The total number of specific functional groups determined by the absorption peak at a given location.

[0068] Specific functional groups can be present at the ends of the main chain or side chains of the perfluoropolymer, or they can be present in the main chain or side chains of the perfluoropolymer. In this disclosure, the specific functional groups are preferably located at the ends of the main chain of the perfluoropolymer. By having specific functional groups at the ends of the main chain, adhesion to the substrate can be improved efficiently. The number of specific functional groups can be the total number of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and CH2OH.

[0069] In this disclosure, the specific functional group is preferably a carbonyl group. More preferably, the specific functional group is at least one group selected from the group consisting of carbonyl amide, carboxyl, acyl fluorine, and methoxy carbonyl. From the viewpoint of imparting adhesive properties, the specific functional group is particularly preferably a carboxyl or carbonyl amide group.

[0070] Specific functional groups can be introduced into perfluoropolymers, for example, through chain transfer agents and / or polymerization initiators used in the manufacture of perfluoropolymers. For instance, when using an alcohol as a chain transfer agent, or when using a peroxide having a -CH2OH structure as a polymerization initiator, -CH2OH is introduced at the end of the perfluoropolymer backbone. Alternatively, specific functional groups can also be introduced into perfluoropolymers by polymerizing monomers having specific functional groups.

[0071] Specific functional groups are preferably introduced into the ends of the perfluoropolymer through chain transfer agents and / or polymerization initiators used in the manufacture of the perfluoropolymer. Perfluoropolymers with this structure exhibit better adhesion to substrates.

[0072] Specific functional groups can also be transformed into functional groups with other structures by further reacting substances introduced to the ends of perfluoropolymers using chain transfer agents and / or polymerization initiators used in the manufacture of perfluoropolymers. Additionally, there are methods for generating functional groups at the ends of the main chain by corona treatment of perfluoropolymer powders or granules.

[0073] The method for manufacturing the perfluoropolymer used in the primer composition disclosed herein is not particularly limited; for example, known polymerization methods such as suspension polymerization can be appropriately selected. The obtained perfluoropolymer can be pulverized or shaped as needed using known methods to produce powder or granules.

[0074] <Specified Powder>

[0075] The specified powder functions, for example, as a heat stabilizer, thereby suppressing foaming of the laminate that may occur when the perfluoropolymer becomes unstable during the heat treatment of the rotating liner. The specified powder is selected from at least one of the following groups: amine antioxidants with a molecular weight of 1000 or less and organic sulfur-containing compounds with a molecular weight of 1000 or less. There is no particular upper limit on the types of specified powders; for example, it may be one or more but no more than five types of powder, or it may be one or two types of powder.

[0076] To suppress foaming in the primer layer of the laminate, the powder content is preferably 0.1% by mass or more relative to the total amount of the primer composition. To suppress foaming in both the primer layer and the topcoat layer of the laminate, the powder content is more preferably 0.5% by mass or more relative to the total amount of the primer composition. To sufficiently reduce the dissolution of components in the primer layer, the powder content is preferably 15.0% by mass or less relative to the total amount of the primer composition, more preferably 5.0% by mass or less. When multiple powders are specified, the powder content is the total content of all powders.

[0077] (Amine-based antioxidants)

[0078] The amine antioxidant used in the primer composition disclosed herein is in powder form. In this disclosure, the amine antioxidant refers to an antioxidant having the structure shown by the chemical formula "-NH-". It should be noted that the amine antioxidant may contain sulfur atoms within its molecule. The molecular weight of the amine antioxidant is 1000 or less. When the molecular weight of the amine antioxidant is 1000 or less, it can suitably suppress foaming of the laminate. There is no particular limitation on the lower limit of the molecular weight of the amine antioxidant, for example, it is 100 or more. The molecular weight of the amine antioxidant can be determined from its molecular formula.

[0079] Examples of amine-based antioxidants with a molecular weight of less than 1000 include aromatic amines containing aromatic hydrocarbon groups such as phenyl or naphthyl groups. Specific examples of amine-based antioxidants with a molecular weight of less than 1000 include phenylenediamine compounds such as N,N'-diphenyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, and the reaction product 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 styrylated diphenylamine; diphenylamine compounds such as p-(p-toluenesulfonamide)diphenylamine; and benzotriazole compounds such as benzotriazole, 2-(2-hydroxy-5-methylphenyl)benzotriazole, and 2-(2-hydroxy-5-tetraoctylphenyl)benzotriazole.

[0080] From the perspective of being able to appropriately suppress the foaming of laminates, amine-based antioxidants with a molecular weight of less than 1000 are preferably phenylenediamine compounds and diphenylamine compounds, and more preferably N,N'-di-2-naphthyl-p-phenylenediamine and p-(p-toluenesulfonamide)diphenylamine.

[0081] Commercially available products can be used as amine-based antioxidants with a molecular weight of less than 1000. Examples of such commercially available products include NOCRAC White and NOCRACTD manufactured by Ouchi Shinsei Chemical Co., Ltd.

[0082] (Organic sulfur compounds)

[0083] 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. There is no particular limitation on the lower limit of the molecular weight of the organic sulfur-containing compound; for example, it is 100 or more. The molecular weight of the organic sulfur-containing compound can be determined from its molecular formula. It should be noted that amine antioxidants having sulfur atoms are exemplified by the aforementioned amine antioxidants. In this disclosure, the organic sulfur-containing compound is a compound other than amine antioxidants having sulfur atoms.

[0084] Specific examples of sulfur-containing organic compounds with a molecular weight of less than 1000 include 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and other mercaptobenzimidazole compounds; 2-mercaptobenzothiazole, cyclohexylamine salts of 2-mercaptobenzothiazole, dibenzothiazole disulfide, 2-(N,N'-diethylthiocarbamoylthio)benzothiazole, 2-(4'-morpholinodithio)benzothiazole, N-cyclohexyl-2-benzothiazole sulfenamide, N-oxodiethylene-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N,N'-dicyclohexyl-2-benzothiazole sulfenamide, and N,N'-diisopropylbenzothiazole-2-sulfenamide. This includes thiol-benzothiazole compounds such as amides; thiol-imidazoline compounds such as 2-mercaptoimidazoline; dithiocarbamates such as pentamethylene dithiocarbamate, pipercolynyl dithiocarbamate, dimethyl dithiocarbamate, diethyl dithiocarbamate, dibutyl dithiocarbamate, and N-ethyl-N-phenyl dithiocarbamate; thiourea derivatives such as thiourea, N,N'-diethylthiourea, N,N'-dibutylthiourea, dilauryl thiourea, and N,N'-diphenylthiourea; and thiuram compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, and dipentamethylenethiuram tetrasulfide. These organic sulfur-containing compounds can be, for example, metal salts of Zn, Sn, Cd, Cu, Fe, etc.; or organic salts of piperidine salts, pipercolyn salts, etc.

[0085] From the perspective of being able to appropriately suppress the foaming of the laminate, the preferred organic sulfur-containing compound with a molecular weight of less than 1000 is a mercaptobenzothiazole compound, its metal salt, or its organic salt, and more preferably a zinc salt of 2-mercaptobenzothiazole.

[0086] For organic sulfur-containing compounds with a molecular weight of less than 1000, commercially available products can be used. Examples of such commercially available products include NOCCELER MZ manufactured by Ouchi Shinsei Chemical Co., Ltd.

[0087] <Other primer components>

[0088] The primer composition disclosed herein may contain only a perfluoropolymer and a specified powder. However, the primer composition disclosed herein may, to the extent necessary and without impairing the effects of the present disclosure, further contain components other than the perfluoropolymer and the specified powder (hereinafter, sometimes referred to as other primer components). There are no particular limitations on other primer components; components used in primers of general coatings may be used. Examples of other primer components include, for instance, pigments, anti-aging agents, leveling agents, solid lubricants, moisture absorbers, surface conditioners, UV absorbers, light stabilizers, plasticizers, color decomposition inhibitors, anti-scratch agents, mildew inhibitors, antibacterial agents, antioxidants, antistatic agents, silane coupling agents, etc. To suppress coating shrinkage, the primer composition may contain fillers as other primer components. Other primer components may be added independently of the perfluoropolymer or integrated with the perfluoropolymer, such as by mixing into the perfluoropolymer. When using other primer components, the content of the other primer components relative to the total amount of the primer composition is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and even more preferably 1% by mass or less.

[0089] To suppress foaming of the laminate, the primer composition disclosed herein preferably does not contain heat stabilizers other than the specified powder. Examples of heat stabilizers other than the specified powder include, for example, metal powders described later.

[0090] To suppress foaming in the top coating of the laminate, the primer composition disclosed herein preferably does not contain metal powder. Examples of metals used as metal powders 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.

[0091] To suppress foaming in the primer layer of the laminate, the primer composition disclosed herein preferably does not contain a binder resin. Examples of binder resins include nitrogen-containing polymers such as polyamides, polyimides, polyamide-imides, and polyetherimides; sulfur-containing polymers such as polyphenylene sulfide, polyaryl sulfide, and polyethersulfone; polyetheretherketone; and polyphenylene carbonate. Nitrogen-containing polymers are, for example, polymers having one or both of amide and imide bonds. By omitting a binder resin with a melting point different from that of the perfluoropolymer in the primer composition, uneven melting of the primer composition is sufficiently reduced during heat treatment using a rotating liner, enabling the easy formation of a uniform primer layer.

[0092] <Method for manufacturing primer composition>

[0093] The primer composition disclosed herein is manufactured, for example, by mixing raw materials using known methods. For instance, the primer composition can be manufactured by mixing a perfluoropolymer, a specified powder, and other primer components added as needed using a mixer. The mixer is not particularly limited; a conventional V-type mixer, a Henschel mixer, or the like can be used. The specified powder can be added either separately from the perfluoropolymer or integrated into the perfluoropolymer during mixing.

[0094] [Layered Body]

[0095] This disclosure also relates to a laminate having a rotational liner coating, i.e., a first layer, formed from the primer composition of this disclosure described above. The laminate of this disclosure has a first layer and a second layer. The first layer is a substrate-side layer. The laminate of this disclosure may further include a substrate. When the laminate includes a substrate, the first layer is disposed on the substrate. The second layer is disposed on the first layer. Hereinafter, "first layer" will sometimes be referred to as "primer layer," and "second layer" will sometimes be referred to as "topcoat layer." The primer layer is a layer disposed further on the substrate side than the topcoat layer.

[0096] The primer composition disclosed herein inhibits foaming of the laminate and exhibits excellent adhesion to the substrate. Therefore, it is preferable to directly apply a rotary liner film, i.e., a primer layer, formed from the primer composition of this disclosure onto the substrate.

[0097] <Substrate>

[0098] The substrate is not particularly limited, and examples include 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, and it can be tubular, for example. When using a tubular substrate, a resin coating can be easily formed inside the substrate while rotating it using a rotating inner liner.

[0099] <Primer layer>

[0100] The primer layer is a rotary liner film formed from the primer composition of this disclosure described above. The thickness of the primer layer can 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 ensuring 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 10000 μm or less, more preferably 8000 μm or less, even more preferably 6000 μm or less, even more preferably 3000 μm or less, and particularly preferably 1500 μm or less. The thickness of the primer layer is measured using a magnetic / eddy current thickness gauge.

[0101] From the perspective of maintaining an appropriate amount of heat stabilizers and other components in the primer layer and reducing the leaching of components, the content of perfluoropolymer powder or granules in the primer layer is preferably 85.0% by mass or more, more preferably 95.0% by mass or more, relative to the total amount of the primer layer. From the perspective of ensuring sufficient amount of heat stabilizers and other components in the primer layer and appropriately suppressing foaming in the primer layer, the content of perfluoropolymer powder or granules in the primer layer is preferably 99.5% by mass or less, relative to the total amount of the primer layer.

[0102] Topcoat

[0103] The top coating layer is, for example, a rotary liner film formed from a top coating composition. The thickness of the top coating layer can be appropriately selected considering the application and other factors. From the viewpoint of uniformly forming the top coating layer and improving the corrosion resistance and chemical resistance of the laminate, the thickness of the top coating layer is preferably 100 μm or more, more preferably 300 μm or more, further 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 top coating layer 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 top coating layer is measured using a magnetic / eddy current thickness gauge.

[0104] The topcoat composition is not particularly limited, and may be, for example, a powder composition containing a fluoropolymer. The topcoat composition preferably comprises a powder or granules of a perfluoropolymer. Examples of perfluoropolymers used in the topcoat composition include, for instance, the same polymers used in the primer composition. The topcoat layer is preferably a rotary liner film formed from a powder or granules of a perfluoropolymer.

[0105] The perfluoropolymer powder or granules contained in the topcoat composition may differ from those contained in the primer composition. However, for good adhesion between the primer layer and the topcoat layer, it is preferable that the perfluoropolymer powder or granules contained in the topcoat composition are the same as those contained in the primer composition.

[0106] The topcoat composition may contain only perfluoropolymers. However, the topcoat composition may also, as needed, further contain components other than perfluoropolymers (hereinafter, sometimes referred to as other topcoat components) without impairing the effects of this disclosure. Examples of other topcoat components include, for instance, the same topcoat components as other primer components. Without impairing the chemical resistance and corrosion resistance of the laminate, the topcoat composition may contain one or both of inorganic fillers and carbon black.

[0107] To minimize the leaching of other topcoat components, the perfluoropolymer content in the topcoat is preferably 99% by mass or more, more preferably more than 99.5% by mass, 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, even 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. The maximum perfluoropolymer content in the topcoat is 100.0% by mass, relative to the total amount of the topcoat.

[0108] The topcoat composition and the topcoat layer formed from the topcoat composition preferably do not contain heat stabilizers. For example, there is a method that suppresses foaming of the laminate by including a heat stabilizer in the topcoat layer formed from a rotary liner. However, the primer composition of this disclosure can suppress foaming of the laminate, so foaming of the laminate can be appropriately suppressed even when the topcoat layer does not contain a heat stabilizer. In addition, by not containing a heat stabilizer in the topcoat layer, it is also possible to obtain the advantages of reducing coloration of the coating caused by heat stabilizers and the absence of leaching of heat stabilizer components. Examples of heat stabilizers include amine antioxidants, organic sulfur compounds, and metal powders. Examples of amine antioxidants include substances similar to those exemplified as amine antioxidants with a molecular weight of 1000 or less used in primer compositions. Examples of organic sulfur compounds include compounds similar to those exemplified as organic sulfur compounds with a molecular weight of 1000 or less used in primer compositions. Examples of metal powders include metal powders similar to those exemplified as metal powders preferably not included in primer compositions. To minimize the leaching of other topcoat components, it is preferable that the topcoat composition and the topcoat layer formed from the topcoat composition do not contain the specified powder.

[0109] To sufficiently reduce the leaching of other topcoat components, it is preferable that the topcoat composition and the topcoat layer formed by the topcoat composition do not contain at least one of the following: binder resin, filler, and inorganic powder. Examples of binder resins include, for example, the same binder resins exemplified as binder resins preferably not included in the primer composition. Examples of fillers include, for example, glass fibers. Examples of inorganic powders include, for example, glass powder and silica powder.

[0110] The topcoat composition and the topcoat layer formed by the topcoat composition preferably do not contain pigments. For example, there is a method in which the coating hue from the heat stabilizer is adjusted by including pigments in the topcoat layer formed by the spin liner. However, the primer composition of this disclosure can suppress foaming of the laminate, thus eliminating the need to add heat stabilizers to the topcoat layer, and consequently, the need to add pigments. By eliminating pigments in the topcoat layer, the advantage of no pigment leaching is obtained.

[0111] <Manufacturing Method of Laminated Materials>

[0112] This disclosure also relates to a method for manufacturing the laminate described above. The method for manufacturing the laminate includes a first layer forming step and a second layer forming step.

[0113] (Layer 1 Formation Process)

[0114] In the first layer forming step, a primer layer is formed on the substrate. In this first layer forming step, the primer layer is formed from the primer composition disclosed herein by rotating the inner liner. More specifically, the primer composition disclosed herein is placed inside a tubular substrate, and the primer composition inside the substrate is heated (e.g., fired) while the substrate is rotated, forming a primer layer on the inner surface of the substrate. To ensure good processing of the perfluoropolymer contained in the primer composition by melting it, the heating temperature in this step is preferably 250–400°C. For the same reason, the heating time is preferably 10 to 300 minutes.

[0115] (Second layer forming process)

[0116] In the second layer forming process, a topcoat layer is formed on the primer layer. In this process, the topcoat layer is formed by rotating the inner liner, for example, using a topcoat composition. More specifically, the topcoat composition is placed inside a tubular substrate on which the primer layer has been formed, and the topcoat composition inside the substrate is heated while the tubular substrate is rotated, forming the topcoat layer on the primer layer (more specifically, the side of the primer layer not bonded to the substrate). To ensure the topcoat composition melts and can be processed effectively, the heating temperature in this process is preferably 250–400°C. For the same reason, the heating time is preferably 10 to 300 minutes.

[0117] [thing]

[0118] This disclosure also relates to articles having the aforementioned laminated structure. There are no particular limitations on the type of article; examples include liquid containers, cans, piping, joints, valves, pipes, and ducts. The articles of this disclosure are particularly suitable for applications where leaching of components contained in the primer and topcoat layers is undesirable. Examples of such applications include semiconductor manufacturing equipment, semiconductor pharmaceutical manufacturing equipment, and liquid containers for semiconductors; medical applications such as pharmaceutical manufacturing equipment and pharmaceutical containers; chemical applications such as chemical manufacturing equipment and chemical containers; food applications such as alcohol brewing containers, fermented food brewing containers, and fermented food storage containers; and steel manufacturing applications such as steel mills.

[0119] The embodiments of this disclosure have been described above, but it should be understood that various changes can be made to the manner and details without departing from the spirit and scope of the claims.

[0120] Example

[0121] The following examples illustrate the present disclosure, but the disclosure is not limited to these examples. In the following examples, unless otherwise specified, "parts" and "%" represent "parts by mass" and "% by mass," respectively.

[0122] The ingredients used in the following examples are as follows.

[0123] Perfluoropolymer A: TFE / PEVE = 95 / 5 mol% (MFR: 8 g / 10 min, average particle size: 162 μm, apparent density: 1.0 g / mL, per 1 × 10 6 Number of specific functional groups in the main chain carbon atoms: 245

[0124] Perfluoropolymer B: TFE / PPVE = 98 / 2 mol% (MFR: 6 g / 10 min, average particle size: 213 μm, apparent density: 1.1 g / mL, per 1 × 10 6 Number of specific functional groups in the main chain carbon atoms: 211)

[0125] Perfluoropolymer C: TFE / HFP = 91 / 9 mol% (MFR: 5 g / 10 min, average particle size: 246 μm, apparent density: 0.7 g / mL, per 1 × 10 6 Number of specific functional groups in the main chain carbon atoms: 147

[0126] 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, per 1 × 10 6 Number of specific functional groups in the main chain carbon atoms: 314)

[0127] Amine antioxidant P: NOCRAC White (compound name: ) manufactured by Ouchi Shinsei Chemical Co., Ltd.

[0128] N,N'-Di-2-naphthyl-p-phenylenediamine, molecular weight: 360)

[0129] Organic sulfur-containing compound: NOCCELER MZ (compound name: zinc salt of 2-mercaptobenzothiazole, molecular weight: 397) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

[0130] Amine antioxidant Q: NOCRAC TD (compound name: p-(p-toluenesulfonamide)diphenylamine, molecular weight: 338) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

[0131] Metal powder R: Zinc powder manufactured by KISHIDA CHEMICAL Co., Ltd.

[0132] Metal powder S: KISHIDA CHEMICAL Co., Ltd. iron powder

[0133] Polyamide-imide: Torlon PAI manufactured by Solvay

[0134] Polyphenylene sulfide (PPS): Ryton PPS manufactured by Solvay

[0135] [Preparation of the primer composition]

[0136] The primer compositions of Examples 1 to 23 and Comparative Examples 1 to 9 were obtained by mixing raw material powders with the compositions recorded in Tables 2 to 5.

[0137] [Formation of the primer layer]

[0138] The inner surface of a 1L mold was sandblasted using alumina powder (manufactured by Uji Denka Kogyo Co., Ltd., TOSA EMERY#40) at a blow pressure of 1.0 MPa. The primer compositions shown in Tables 2-5 were then sealed into the sandblasted mold in the amounts required to achieve the target film thicknesses shown in Tables 2-5. The mold was then heated at 380°C for 60 minutes using a rotary liner molding machine. This formed a primer layer on the inner surface of the mold.

[0139] [Formation of the top coating]

[0140] A topcoat composition with a film thickness of 2000 μm was sealed into the mold in which the primer layer had been formed, and heated at 350°C for 90 minutes using a rotary liner molding machine. Thus, a topcoat layer was formed on the primer layer formed on the inner surface of the mold, resulting in a rotary liner laminate. It should be noted that the topcoat composition used was either Daikin Industries AC-5820 (pure PFA powder) or Daikin Industries AC-5830 (a mixture of PFA powder, amine antioxidant, and organic sulfur-containing compound) as shown in Tables 2 to 5.

[0141] [Evaluation Method]

[0142] After the primer layer is formed and before the topcoat layer is formed, observe the primer layer formed on the inner surface of the mold to confirm whether there is foaming or peeling (coating peeling) in the primer layer. Evaluate the adhesion between the primer layer and the mold according to the following criteria: "Foaming" and "B" are judged as unacceptable, and "A" is judged as acceptable.

[0143] Foaming: The primer layer has foaming.

[0144] B: Some parts have peeling film.

[0145] A: Coating peeling not confirmed.

[0146] <State of the rotating inner liner laminate>

[0147] The appearance of the obtained rotary liner laminate (more specifically, the appearance of the top coating layer) is observed and evaluated according to the following criteria. "C" and "B" are deemed unacceptable, and "A" is deemed acceptable.

[0148] C: Massive foaming of the rotating inner lining laminate

[0149] B: The rotating inner liner laminate has slight micro-foaming.

[0150] A: The rotating inner liner laminate is not foamed.

[0151] <Amount of extract from the rotating inner liner laminate>

[0152] For the three representative rotary liner laminates (rotary liner laminates formed using the primer compositions of Examples 5, 6, and 15) obtained above, the extract content was determined. A 3.5% HCl aqueous solution was added to the containers of the three rotary liner laminates, and the mixtures were allowed to stand at 25°C for 7 days. Then, the total extract content of 17 elements (Ag, Al, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Ti, Zn) was determined by inductively coupled plasma optical emission spectrometry. It should be noted that this extract content mainly corresponds to the dissolution of components from the primer and topcoat layers.

[0153] The evaluation results are shown in Tables 2 to 5. It should be noted that a "-" in the primer composition column of Tables 2 to 5 indicates that the corresponding component was not added. A "-" in the topcoat composition column and the status column of the rotating liner laminate in Tables 2 to 5 indicates that topcoat formation was not performed because foaming was observed in the primer layer. A "-" in the extract amount column from the rotating liner laminate in Tables 2 to 5 indicates that extract measurement was not performed.

[0154]

[0155]

[0156]

[0157]

[0158] As can be seen from the above evaluation results, the primer composition of this disclosure can suppress foaming of the laminate when used as a primer layer to form a laminate.

[0159] Industrial availability

[0160] The primer composition disclosed herein is suitable for use as a primer when applying fluoropolymers using a rotary liner.

Claims

1. A primer composition for use with rotating linings, characterized in that, The primer composition comprises a powder or granules of a perfluoropolymer and at least one specified powder selected from the group consisting of an amine antioxidant with a molecular weight of less than 1000 and an organic sulfur-containing compound with a molecular weight of less than 1000.

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 granules is 95.0% by mass or more and 99.5% by mass or less relative to the total amount of the primer composition.

4. The primer composition according to claim 1 or 2, wherein, The content of the specified powder is 0.5% by mass or more and 5.0% by mass or less relative to 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 granules is above 150 μm and below 500 μm.

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

7. The primer composition according to claim 1 or 2, wherein it does not contain metal powder.

8. The primer composition according to claim 1 or 2, wherein it does not contain nitrogen-containing polymers or sulfur-containing polymers.

9. The primer composition according to claim 1 or 2, 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). The content of the perfluoropolymer powder or granules is 95.0% by mass or more and 99.5% by mass or less relative to the total amount of the primer composition. The amine-based antioxidant is a phenylenediamine compound or a diphenylamine compound. The organic sulfur-containing compound is a mercaptobenzothiazole compound or its metal salt. The content of the specified powder is 0.5% by mass or more and 5.0% by mass or less relative to the total amount of the primer composition.

10. A laminate comprising a first layer serving as a substrate and a second layer disposed on the first layer, wherein, The first layer is a rotary inner liner coating formed by the primer composition of claim 1 or 2.

11. The laminate according to claim 10, wherein, The second layer is a rotary inner liner film formed from the powder or granules of the perfluoropolymer. The second layer does not contain amine antioxidants, organic sulfur compounds, or metal powders.

12. The laminate according to claim 10, wherein, The second layer is a rotary inner liner film formed from the powder or granules of the perfluoropolymer. The perfluoropolymer content in the second layer is 99% by mass or more relative 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 of claim 10.

15. A method for manufacturing a laminate, comprising: The first layer forming process, which forms a first layer on a substrate, and the second layer forming process, which forms a second layer on the first layer, wherein, In the first layer forming process, the first layer is formed using a rotating inner liner from the primer composition of claim 1 or 2.

16. The method for manufacturing a laminate according to claim 15, wherein, In the second layer forming process, the second layer is formed using a rotating inner liner.

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