Thermosetting release coating agent composition and laminate

Abstract

One embodiment of the present application is a thermosetting release coating agent composition, which is a thermosetting release coating agent composition containing an alkyl-etherified melamine resin (A) and an acid catalyst (B), contains an ethyl ether group as an alkyl ether group contained in the alkyl-etherified melamine resin (A), and has a weight average molecular weight of the alkyl-etherified melamine resin (A) of 500 to 1,100.

Description

Technical Field

[0001] One aspect of the present invention relates to a thermosetting release coating composition comprising an alkyl etherified melamine resin (A), and a laminate comprising a cured layer formed from the thermosetting release coating composition. Background Technology

[0002] Among release coating agents, melamine resin has been used as a component in applications requiring heat resistance, such as release films for ceramic green bodies, due to its superior heat resistance, curing properties, and cost.

[0003] With the aim of controlling polarity, storage stability and reactivity, melamine resins are mostly used in the form of alkyl etherified melamine resins obtained by modifying melamine with formaldehyde addition using various alcohols.

[0004] For example, a release film for ceramic green body manufacturing process having a release layer containing methyl etherified melamine resin (methylated melamine resin) as melamine resin was studied (see Patent Document 1).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-166706 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] As mentioned above, methyl etherified melamine resin obtained by modifying with methanol has excellent curing properties and is therefore increasingly widely used as the main component of release coating agents. However, the methyl ether group is highly polar, and due to this main factor, it absorbs moisture from the air when applied under high humidity conditions, sometimes causing whitening and other poor appearance of the coating film (cured coating film) after curing.

[0010] In recent years, in particular, with the globalization of release film manufacturing bases, there has been an increase in production opportunities in regions with high humidity (temperature). The resulting decrease in productivity caused by the aforementioned adverse conditions has become a critical issue, requiring release coating agents with low humidity dependence.

[0011] In addition, for methyl etherified melamine resin, curing at a relatively high temperature (e.g., 120°C) is required to bring out its properties. However, given the social situation such as global warming, the expectation of reducing carbon dioxide emissions through low-temperature curing is increasing year by year. There is a demand that melamine resin can exhibit the various properties required even when it is cured at a lower temperature than the previous curing temperature (e.g., 120°C) (e.g., 80°C).

[0012] One aspect of the present invention is to provide a thermosetting release coating composition comprising an alkyl etherified melamine resin, wherein the thermosetting release coating composition, when formed into a cured coating film, can suppress coating appearance defects such as whitening, and when cured at low temperature, also exhibits excellent adhesion, solvent resistance, and other properties, and thus excellent storage stability.

[0013] Methods for solving problems

[0014] The inventors of this application conducted research and found that the aforementioned problems can be solved by using a thermosetting release coating composition comprising a specific alkyl etherified melamine resin and an acid catalyst.

[0015] That is, one aspect of the present invention includes the following:

[0016] [1] A thermosetting release coating composition comprising an alkyl etherified melamine resin (A) and an acid catalyst (B).

[0017] The alkyl ether group contained in the alkyl etherified melamine resin (A) includes an ethyl ether group, and the weight average molecular weight of the alkyl etherified melamine resin (A) is 500 to 1,100.

[0018] [2] The thermosetting peeling coating composition as described in [1], wherein, as an alkyl ether group contained in the alkyl etherified melamine resin (A), it further comprises a methyl ether group.

[0019] The molar ratio of methyl ether group to ethyl ether group (methyl ether group) / (ethyl ether group) is less than 90 / 10.

[0020] [3] The thermosetting release coating composition as described in [1] or [2], wherein the alkyl etherified melamine resin (A) contains an average molar ratio of 3 to 6 of alkyl ether groups relative to 1 mole of triazine ring.

[0021] [4] The thermosetting stripping coating composition as described in any one of [1] to [3], wherein the acid catalyst (B) is p-toluenesulfonic acid.

[0022] [5] The thermosetting release coating composition as described in any one of [1] to [4] further comprises a release component (C).

[0023] [6] The thermosetting peeling coating composition as described in any one of [1] to [5], wherein the concentration of carbon (C14) from biomass contained in the alkyl etherified melamine resin (A) is 20% to 100% of the total organic carbon.

[0024] [7] The thermosetting release coating composition as described in any one of [1] to [6], wherein the content of alkyl etherified melamine resin (A) is 10 to 99 parts by weight relative to 100 parts by weight of solid components contained in the aforementioned thermosetting release coating composition.

[0025] [8] A laminate having a cured layer on at least one side of a substrate, wherein the cured layer is formed from any one of the thermosetting release coating compositions described in [1] to [7].

[0026] [9] The laminate as described in [8], wherein the aforementioned substrate is polyethylene terephthalate.

[0027]

[10] The laminate as described in [9], wherein the aforementioned substrate is untreated polyethylene terephthalate.

[0028] Invention Effects

[0029] The coating obtained by applying and curing a thermosetting release coating composition comprising alkyl etherified melamine resin, as described in one embodiment of the present invention, can suppress coating appearance defects such as whitening, and exhibits excellent adhesion and solvent resistance even when cured at low temperatures. Furthermore, the thermosetting release coating composition also demonstrates excellent storage stability. Detailed Implementation

[0030] [Thermosetting release coating composition]

[0031] In one embodiment of the present invention, a thermosetting release coating composition comprises an alkyl etherified melamine resin (A) and an acid catalyst (B).

[0032] <Alkyl etherified melamine resin (A)>

[0033] In one aspect of the thermosetting release coating composition of the present invention, an alkyl etherified melamine resin (A) is included. Here, the melamine resin is a resin obtained from a raw material containing melamine and formaldehyde, and as an example, the alkyl etherified melamine resin is a resin obtained from a raw material containing melamine, formaldehyde, and an alcohol for alkyl etherification.

[0034] In the aforementioned alkyl etherified melamine resin (A), the alkyl ether group contained in the resin includes an ethyl ether group. By including an ethyl ether group as an alkyl ether group in the alkyl etherified melamine resin, poor appearance of the coating film (cured coating film) obtained by coating and curing a thermosetting release coating composition containing alkyl etherified melamine resin (A) can be suppressed, and the adhesion to the substrate and storage stability at low temperatures can be improved.

[0035] From the viewpoint of suppressing poor appearance of the coating film (cured coating film) obtained by the thermosetting peel coating agent composition involved in one aspect of the present invention, and further improving solvent resistance, the aforementioned alkyl etherified melamine resin (A) preferably further comprises a methyl ether group.

[0036] When the alkyl etherified melamine resin (A) contains ethyl ether groups and methyl ether groups, from the viewpoint of improving solvent resistance, the molar ratio of methyl ether group to ethyl ether group (methyl ether group) / (ethyl ether group) is preferably 90 / 10 or less, more preferably 50 / 50 or less, and even more preferably 30 / 70 or less.

[0037] In addition, when both ethyl ether and methyl ether groups are included, the aforementioned molar ratio (methyl ether group) / (ethyl ether group) is usually 5 / 95 or higher.

[0038] From the viewpoint of more significantly presenting the effects of the present invention, the total content of ethyl ether groups and, if necessary, methyl ether groups is preferably 80 to 100 mol% relative to all alkyl ether groups contained in the alkyl etherified melamine resin (A). More preferably, it is 90 to 100 mol%. Furthermore, from the same viewpoint, all alkyl ether groups are preferably only ethyl ether groups, or only ethyl ether groups and methyl ether groups, more preferably only ethyl ether groups and methyl ether groups.

[0039] It should be noted that the identification of the types of alkyl ether groups contained in the alkyl etherified melamine resin (A), as well as their contents and molar ratios when multiple alkyl ether groups are contained, can be determined by gas chromatography-mass spectrometry (GC).

[0040] The alcohols (e.g., ethanol or methanol) detected by measurement originate from the alkyl ether groups of the alkyl etherified melamine resin (A). Therefore, the number (moles) of alkyl ether groups contained in the alkyl etherified melamine resin (A) can be determined from the amount of alcohol produced.

[0041] The aforementioned alkyl etherified melamine resin (A) has a weight-average molecular weight (Mw) of 500 to 1,100, preferably 600 to 1,100, as determined by GPC (gel permeation chromatography) based on polystyrene. By ensuring that the weight-average molecular weight of the alkyl etherified melamine resin (A) is within the aforementioned range, not only is solvent resistance improved, but also poor appearance of the coating film (cured coating film) obtained from the thermosetting release coating agent composition is suppressed. Furthermore, even when cured at a lower temperature, the coating film obtained from the thermosetting release coating agent composition exhibits excellent adhesion to the substrate. In addition, the thermosetting release coating agent demonstrates excellent storage stability at low temperatures.

[0042] From the viewpoint of improving the solvent resistance of the coating film (cured coating film) obtained by the thermosetting release coating composition of the present invention, the average molar ratio of the alkyl ether group contained in the aforementioned alkyl etherified melamine resin (A) to 1 mole of the triazine ring, which is a backbone component of melamine, is preferably 3 to 6, more preferably 4 to 6.

[0043] When the average molar ratio of alkyl ether group to triazine ring is less than 3 per mole, the crosslinking density is insufficient, raising concerns about reduced solvent resistance.

[0044] It should be noted that the molar number of alkyl ether groups and triazine rings in the aforementioned alkyl etherified melamine resin (A) can be determined using nuclear magnetic resonance spectroscopy. 13 The result is obtained using C-NMR.

[0045] From the perspective of suppressing the use of raw materials from fossil fuels and producing resins that can contribute to environmental protection, the concentration of carbon (C14) from biomass in the total organic carbon of the alkyl etherified melamine resin (A) is preferably 20 to 100%, more preferably 30 to 100%.

[0046] The biomass-derived carbon (C14) concentration of the alkyl etherified melamine resin (A) can be determined based on the American Standard for Test Materials (ASTM D6866 Method B). It should be noted that the calculation method is detailed in the examples described later.

[0047] The content of alkyl etherified melamine resin (A) in the thermosetting release coating composition according to one aspect of the present invention is preferably 10 to 99 parts by weight, more preferably 50 to 98 parts by weight, relative to 100 parts by weight of the solid components contained in the composition.

[0048] The aforementioned method for manufacturing alkyl etherified melamine resin (A) is not particularly limited as long as it can produce a resin that meets its requirements. For example, a preferred method for manufacturing alkyl etherified melamine resin (A) includes a step of first performing a hydroxymethylation reaction using melamine and formaldehyde, followed by an alkyl etherification reaction. More preferably, a step is included where melamine, formaldehyde, and an alcohol are added to a reaction vessel, heated to reflux temperature, and then an acid is used as a catalyst to carry out a condensation reaction of the aforementioned three components.

[0049] Melamine

[0050] As for the aforementioned melamine, there are no particular restrictions; it can be synthesized using previously known methods and can also be a commercially available product.

[0051] 〔formaldehyde〕

[0052] The aforementioned formaldehyde can be an aqueous solution or solid paraformaldehyde. From an economic point of view, paraformaldehyde with a formaldehyde concentration of 80% or higher is preferred.

[0053] When the amount of melamine used is set to 1 mole, the amount of formaldehyde used is preferably 3 to 12 moles, more preferably 4 to 10 moles. If the amount of formaldehyde used is within the aforementioned range, the alkyl etherified melamine resin (A) used in this invention can be manufactured efficiently.

[0054] 〔alcohol〕

[0055] In the aforementioned process, ethyl etherified melamine resin can be manufactured by using ethanol as the alcohol. By using this ethyl etherified melamine resin, poor appearance of the coating film (cured coating film) obtained from the thermosetting release coating agent composition can be suppressed, and the coating film obtained from the thermosetting release coating agent composition also exhibits excellent adhesion to the substrate when cured at a lower temperature.

[0056] Here, if methanol is used as the alcohol, methyl etherified melamine resin can be obtained, but it easily leads to poor appearance of the coating film (cured coating). On the other hand, if butanol is used as the alcohol, butyl etherified melamine resin can be obtained, which is less likely to cause poor appearance of the coating film (cured coating), but the crosslinking reaction is slow, so it is believed that there is a tendency for the solvent resistance of the obtained cured product to decrease.

[0057] When the amount of melamine used is set to 1 mole, the amount of ethanol used is preferably 3 to 20 moles, more preferably 5 to 12 moles. If the amount of ethanol used is within the aforementioned range, the alkyl etherified melamine resin (A) used in this invention can be manufactured efficiently and inexpensively.

[0058] It should be noted that, as long as the purpose of this invention is not compromised, ethanol and a small amount of C can also be used. n H 2n+1 A mixture of other alcohols represented by OH (n is an integer from 1 to 3 to 8).

[0059] From the perspective of economy and coating (cured coating) performance, n is preferably 1, 3 or 4.

[0060] <Acid Catalyst (B)>

[0061] The thermosetting release coating composition of the present invention also contains an acid catalyst (B). By including the acid catalyst (B), the aforementioned condensation (crosslinking) reaction based on melamine resin can be carried out efficiently.

[0062] As the aforementioned acid catalyst (B), any acid from organic and inorganic acids can be used. Examples of organic acids include formic acid, oxalic acid, methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and alkyl phosphoric acid. Examples of inorganic acids include phosphoric acid, phosphorous acid, hydrochloric acid, sulfuric acid, nitric acid, and hydrobromic acid.

[0063] Among the aforementioned acid catalysts (B), organic acids are preferred, more preferably p-toluenesulfonic acid, methanesulfonic acid, and dodecylbenzenesulfonic acid, and particularly preferably p-toluenesulfonic acid. These have high acidity and excellent reactivity, thus enabling the release layer to be processed at lower temperatures. Therefore, it is possible to suppress the reduction in film planarity and the deterioration of the wound appearance caused by heat during processing.

[0064] The content of acid catalyst (B) in the thermosetting release coating composition of the present invention is preferably 1 to 10 parts by weight, more preferably 3 to 8 parts by weight, relative to 100 parts by weight of alkyl etherified melamine resin (A). By keeping the content of acid catalyst (B) within the aforementioned range, the curing reaction is carried out efficiently. In addition, there is no concern that the acid catalyst will migrate to the object to which it is used (e.g., ceramic green body described later) in which the cured layer (typically a release layer) obtained by curing the aforementioned composition is laminated. The durability is excellent.

[0065] <Exfoliating Component (C)>

[0066] In one aspect of the thermosetting release coating composition of the present invention, a release component (C) is preferably included. This release component (C) is not particularly limited, as long as it is an ingredient capable of imparting the desired release properties to the cured layer (release layer). Examples include release polymers such as polysiloxanes, silicone-modified acrylic resins, fluoropolymers, and acrylic resins. Among these, polysiloxanes are preferred. The aforementioned release polymers can be used individually, in combination, or in mixtures.

[0067] In one aspect of the thermosetting release coating composition of the present invention, the release component (C) is preferably a release polymer component having one or more functional groups per molecule that can chemically bond with an alkyl etherified melamine resin (A). Examples of such functional groups include alkoxy groups such as methoxy, hydroxyl, amino, carboxyl, epoxy, thiol, and isocyanate groups. By giving the release component (C) the aforementioned functional groups, the release polymer component (e.g., a polyorganosiloxane) can be fixed to the melamine cured product through a condensation reaction with the melamine resin. As a result, migration of components from the release component (C) into the object to be used (e.g., a ceramic green body) laminated with the cured layer (release layer) obtained by curing the above-mentioned thermosetting release coating composition can be suppressed, preventing re-peeling during tape storage and reduction of adhesion during use.

[0068] When the aforementioned release component (C) is a polyorganosiloxane, its weight-average molecular weight (Mw) is preferably 1,000 to 10,000, more preferably 9,000 or less, and particularly preferably 3,000 to 8,000. By keeping the weight-average molecular weight of the polyorganosiloxane within the aforementioned range, the compatibility between the polyorganosiloxane and melamine resin becomes more excellent, and it is easier to form a release layer with excellent surface condition. In addition, the surface free energy in the release surface can be easily adjusted to a suitable range. As a result, it is easy to simultaneously achieve excellent release properties and excellent slurry coating properties in the laminate (e.g., release film) according to one embodiment of the present invention.

[0069] Examples of the stripping component (C) as described above include: BYK-370, BYK-375, BYK-377, and BYK-SILCLEAN (manufactured by BYK Japan), x-22-4952 (manufactured by Shin-Etsu Chemical Industry Co., Ltd.), and FM-4425 (manufactured by JNC Corporation) as polyorganosiloxanes containing hydroxyl groups; and x-22-162C, x-22-3701E, and x-22-3710 (manufactured by Shin-Etsu Chemical Industry Co., Ltd.), and Dow Corning Toray Silicone Co., Ltd. as polyorganosiloxanes containing carboxyl groups. d. BY16-750, BY16-880; x-22-167B, a polyorganosiloxane containing a mercapto group, manufactured by Shin-Etsu Chemical Industry Co., Ltd.; x-22-161B, a polyorganosiloxane containing an amino group, manufactured by Shin-Etsu Chemical Industry Co., Ltd.; x-22-163B, a polyorganosiloxane containing an epoxy group, etc.

[0070] The content of the release component (C) in the thermosetting release coating composition according to one aspect of the present invention is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, relative to 100 parts by weight of alkyl etherified melamine resin (A). By keeping the content of the release component (C) within the aforementioned range, the desired release properties can be easily achieved for objects (e.g., ceramic green bodies) on which a cured layer (release layer) obtained by curing the thermosetting release coating composition is laminated, and the migration of polyorganosiloxane from the release layer to the object can be effectively suppressed.

[0071] Solvent

[0072] In the thermosetting release coating composition according to one aspect of the present invention, a solvent is typically included to take into account its coatability, etc. Even in the case where a solvent is included in the thermosetting release coating composition, when the aforementioned alkyl etherified melamine resin (A) is included as the melamine resin, its storage stability is excellent when stored at low temperatures.

[0073] There are no particular limitations on the solvent used, as long as it can dissolve the aforementioned components. Examples of solvents include hydrocarbon compounds such as toluene, xylene, hexane, and heptane; alcohol compounds such as methanol, ethanol, 1-butanol, isopropanol, and isobutanol; ketone compounds such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester compounds such as ethyl acetate and butyl acetate; and ether compounds such as diisopropyl ether and 4-dioxane. One solvent may be used alone, or two or more may be used in combination as appropriate.

[0074] In one aspect of the present invention, from the viewpoint of dissolving the stripping component (C), toluene or methyl ethyl ketone is preferred, and toluene is more preferred.

[0075] In the case where the thermosetting release coating composition of one aspect of the present invention contains a solvent, from the viewpoint of its coatability, the amount of the formulation is preferably 420 to 1995 parts by weight, more preferably 595 to 1395 parts by weight, relative to 100 parts by weight of alkyl etherified melamine resin (A).

[0076] <Other Ingredients>

[0077] The thermosetting release coating composition according to one aspect of the present invention may also contain other components, as long as they do not impair the effects of the present invention. Examples of such other components include, for instance, binders, crosslinking agents, reaction inhibitors, adhesion improvers, lubricants, antistatic agents, antioxidants, leveling agents, fillers, defoaming materials, pigments, and other additives.

[0078] [Adhesive]

[0079] The aforementioned adhesive is any compound having two or more hydroxyl groups in one molecule (excluding alkyl etherified melamine resin (A)). There are no particular limitations, and various known adhesives can be used.

[0080] Specifically, examples include aliphatic diols such as ethylene glycol, 2-methyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentanediol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,9-nonanediol, 1,10-decanediol, butylethylpropanediol, and butylethylpentanediol; alicyclic diols such as 1,4-cyclohexanediol; trimethylolpropane, pentaerythritol, bis(trimethylolpropane), dipentaerythritol, dimer diol, hydrogenated dimer diol, trimer triol, hydrogenated trimer triol, castor oil, castor oil-modified polyols, and epoxide adducts of bisphenol compounds or their derivatives. Additionally, examples include polymeric polyols such as polyether polyols, polyester polyols, polycarbonate polyols, acrylic polyols, and polyolefin polyols. They can be used individually or in combination of two or more.

[0081] [Cross-linking agent]

[0082] The aforementioned crosslinking agent can be any compound with a functional group that can bond with a hydroxyl group; there are no particular limitations, and various known crosslinking agents can be used.

[0083] Specifically, examples include isocyanate-based curing agents, epoxy-based curing agents, aziridine-based curing agents, carbodiimide-based curing agents, and oxazoline-based curing agents. These can be used individually or in combination of two or more.

[0084] The aforementioned binders and crosslinking agents can both be used to improve the curability of the thermosetting release coating composition of the present invention. Furthermore, the content of the aforementioned binders and crosslinking agents is not particularly limited, as long as it does not impede the effects of the present invention, as described above.

[0085] [Laminated body, release film]

[0086] A thermosetting release coating composition according to one aspect of the present invention, obtained as described above, is applied to a substrate to form a coating layer. Typically, the coating layer is heated and cured, thereby forming a laminate comprising a cured layer (typically a release layer) as a coating film obtained from the thermosetting release coating composition and a substrate. The laminate according to one aspect of the present invention can be suitably used as a release film.

[0087] <Substrate>

[0088] As the substrate for the aforementioned laminate (e.g., a release film), examples include films formed from polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polypropylene, polyolefins such as polymethylpentene, polycarbonate, and polyvinyl acetate. These films can be single-layered or multilayered with two or more layers of the same or different materials. Among these, polyester films are preferred, and polyethylene terephthalate films are particularly preferred.

[0089] PET film is less prone to dust generation during processing and use, thus effectively preventing issues such as poor ceramic slurry coating caused by dust. Furthermore, antistatic treatment of the PET film enhances its ability to prevent fires caused by static electricity during the application of ceramic slurries using organic solvents, and also prevents poor coating. To improve the adhesion between these substrates and the cured layer (release layer), substrates obtained by corona treatment, etching, plasma treatment, adding organic or inorganic particles to create an uneven surface, or coating with urethane or polyester can be used. In this specification, substrates that have not undergone these treatments are referred to as "untreated" substrates.

[0090] The aforementioned substrate can also be an untreated substrate, and the thermosetting release coating composition of the present invention also exhibits excellent adhesion to untreated PET films, for example.

[0091] <Cure layer, release layer>

[0092] The cured layer (typically a release layer) of the aforementioned laminate (e.g., a release film) can be formed by applying a thermosetting release coating composition according to one aspect of the present invention to one side of a substrate, typically by heating it. Because the cured layer (release layer) of the laminate is formed from a thermosetting release coating composition according to one aspect of the present invention, excellent adhesion to the substrate (e.g., a PET film) is achieved even when curing is performed at a lower temperature.

[0093] The thickness of the aforementioned cured layer (release layer) is preferably 0.01 μm or more, more preferably 0.03 μm or more, even more preferably 0.05 μm or more, and particularly preferably 0.1 μm or more. Furthermore, this thickness is preferably 2.0 μm or less, more preferably 1.0 μm or less, and even more preferably 0.5 μm or less. By making the thickness of the release layer 0.01 μm or more, sufficient release properties are achieved for objects (e.g., ceramic green bodies) that are laminated with the cured layer (release layer) when, for example, the aforementioned laminate is used as a release film. Furthermore, by making the thickness of the cured layer (release layer) 2.0 μm or less, adhesion can be suppressed when the release film is rolled into a roll. For example, when the release film is used for molding ceramic green bodies, the curing time can be shortened, the planarity of the release film can be ensured, and uneven thickness of the resulting ceramic green body can be suppressed.

[0094] The cured layer (release layer) obtained from the thermosetting release coating composition according to one aspect of the present invention is preferably flat. For example, when the laminate obtained from this composition is used as a release film for forming ceramic green bodies, if the cured layer (release layer) is flat, defects such as pinholes and uneven thickness in the ceramic green body coated and formed on the cured layer (release layer) can be suppressed. By forming the cured layer (release layer) from a release agent composition containing a dispersant, the compatibility of the components contained in the release agent composition with each other is improved, and as a result, the above-mentioned conditions are easily met.

[0095] <Fabrication of Laminated Materials and Release Films>

[0096] Regarding the method of applying the thermosetting release coating composition of the present invention to a substrate for making a laminate (e.g., a release film), there are no particular limitations as long as a layer formed by the coating can be formed on the substrate. For example, it can be made using known methods such as gravure coating, bar coating, spray coating, spin coating, doctor blade coating, roller coating, and mold coating.

[0097] For a coating formed by a thermosetting release coating composition according to one aspect of the present invention and applied to a substrate, the volatile components (e.g., solvents) of the coating are removed, and the solid components contained in the coating are cured to form a cured layer (typically a release layer) of a laminate (release film).

[0098] The preferred coating amount is 0.01–100 g / m². 2 More preferably, it is 0.03–50 g / m 2 It should be noted that when a cured layer (release layer) is formed on both sides of the substrate, it is preferable to perform the operation of forming a cured layer (release layer) as a cured film on each side of the substrate.

[0099] The solid components of this thermosetting release coating composition are typically cured by heating. Regarding the heating conditions for this curing, when using the thermosetting release coating composition according to one aspect of the present invention, it is possible to perform the curing at a lower temperature than previously possible. The preferred heating temperature for curing the thermosetting release coating composition is 60°C to 140°C, more preferably 80°C to 120°C. If curing at a lower temperature is desired, a temperature range of 70°C to 90°C can be selected. Furthermore, the preferred heating time for curing is 0.5 minutes to 5 minutes, more preferably 1 minute to 3 minutes.

[0100] As described above, in this invention, curing can be performed at a lower temperature, and therefore, a reduction in the amount of carbon dioxide generated during heating can be expected.

[0101] [Ceramic green body]

[0102] The laminate obtained as described above can be suitably used as a release film, which can be suitably used in the manufacturing process of ceramic green films. The ceramic green film, for example, becomes the raw material for laminated ceramic capacitor films.

[0103] A laminated ceramic capacitor film typically has the following configuration: The laminated ceramic capacitor film has a rectangular ceramic body. Inside the ceramic body, a first internal electrode and a second internal electrode are typically alternately arranged along the thickness direction. The first internal electrode is exposed at a first end face of the ceramic body, and a first external electrode is disposed at the first end face. The first internal electrode is electrically connected to the first external electrode at the first end face. The second internal electrode is exposed at a second end face of the ceramic body. A second external electrode is disposed at the second end face. The second internal electrode is electrically connected to the second external electrode at the second end face.

[0104] The ceramic green body that becomes the raw material for such a laminated ceramic capacitor film can be made using the aforementioned release film as described below.

[0105] First, a ceramic slurry containing ceramic materials such as barium titanate and titanium oxide is applied to the release surface of the aforementioned release film. This application can be performed using methods such as stencil application or scraper application. Examples of binder components in the ceramic slurry include butyral resins and acrylic resins. Examples of solvents in the ceramic slurry include organic solvents and aqueous solvents. After applying the slurry to the release surface, the applied ceramic slurry is dried, thereby enabling the formation of a ceramic green body. Regarding the thickness of the ceramic green body, an extremely thin product of 0.2 to 1.0 μm is typically required.

[0106] For the ceramic green body produced, conductive layers for forming the first or second internal electrodes are printed on it, and used as raw materials for the multilayer ceramic capacitor film. The multilayer ceramic capacitor can be manufactured by dividing the multilayer body obtained by properly stacking and pressing into multiple parts, firing them to obtain the ceramic body, and then forming the first and second external electrodes.

[0107] [Transfer Foil Sheet]

[0108] Furthermore, the release film obtained as described above can also be suitable for manufacturing transfer foil sheets, serving as a release film for transfer foil or a decorative release film for transfer foil. The transfer foil sheet using this film typically comprises the following structure: a release layer is provided on one side of a polyester film serving as a substrate film, and transfer layers such as a pattern printing layer, a coloring layer, and an adhesive layer are sequentially laminated on this release layer. Depending on the purpose, a hard coating layer, a metal vapor deposition layer, etc., may be laminated on the transfer layers. In addition, functional additives such as antistatic agents and antibacterial agents can be added to these release layers and transfer layers to impart the function of a transfer foil.

[0109] Transfer methods using the aforementioned release film on transfer foil are commonly known, including heat transfer (hot stamping) and in-mold transfer (molding). The substrate to which the transfer layer is applied can be molded articles made of glass, metal, ceramics, resin, paper, or blanks; there are no particular restrictions on the raw materials. Furthermore, the shape of the substrate can be any shape, such as a pre-formed plate, film, sheet, or any desired shape. Thus, it is used for a wide range of applications for surface finishing purposes such as decoration and protection of the substrate.

[0110] Example

[0111] The present invention will now be described in more detail based on embodiments, but the present invention is not limited to the description of these embodiments.

[0112] The methods for determining the physical properties of the materials used in the examples and comparative examples are as follows.

[0113] <Weight-average molecular weight>

[0114] The weight-average molecular weight of alkyl etherified melamine resin (A) was determined using GPC under the following conditions.

[0115] Device: Shodex GPC-101 manufactured by Showa Denko Co., Ltd.

[0116] Detector: RI-71S

[0117] Column: Showa Denko Co., Ltd. GPCKF804L (Φ8.0mm×300mm)×3 pieces Measurement temperature: 40℃

[0118] Eluent: THF (Tetrahydrofuran)

[0119] Flow rate: 1.0 ml / min

[0120] <Alkyl ether group content ratio>

[0121] For the alkyl ether content ratio of alkyl etherified melamine resin (A), 20 mg (or 10 mg) of sample (melamine resin) was placed in a 20 ml vial and sealed tightly. Using a headspace sampler (Agilent G1888), the sample was heated at 150 °C for 30 minutes. The headspace gas was then measured by gas chromatography-mass spectrometry (GC) using a gas chromatograph (Agilent 6890GC / 5973MSD).

[0122] Here, for example, in determining the content of ethanol as an alcohol, the amount produced is determined by using the peak area of ​​the retention time obtained through extraction ion chromatography using characteristic fragmented ions in the mass spectrometry of ethanol, and then by using an absolute standard curve method. In determining the content of methanol, the amount produced is determined by using the peak area of ​​the retention time, and then by using an absolute standard curve method. The molar ratio of methyl ether groups to ethyl ether groups is then calculated from this amount produced.

[0123] <Average molar ratio of alkyl ether group to 1 mole of triazine ring>

[0124] Regarding the average molar ratio of the alkyl ether group to 1 mole of the triazine ring in the alkyl etherified melamine resin (A), the sample (melamine resin) after the dilution solvent has evaporated will be dissolved in deuterated DMSO under the following conditions. 13 C-NMR determination.

[0125] Apparatus: Bruker AVANCE NEO cryo-500 NMR spectrometer; nucleus measured: 13C (125MHz)

[0126] Measurement mode: Single-pulse inverse-gated proton decoupling

[0127] Pulse width: 90 degrees (10.0 μs)

[0128] Points: 64 times

[0129] Observation range: 250ppm (-25 to 225ppm)

[0130] Repeat time: 20.0s

[0131] Total number of times: 64

[0132] Measurement temperature: 25℃

[0133] Window function: exponential(BF: 1.0Hz)

[0134] Based on the following attribution, calculate the integral ratio and determine the molar ratio of the alkyl ether group relative to the triazine ring.

[0135] Triazine ring: 164–169 ppm

[0136] Methyl ether group: 54-58 ppm

[0137] Ethyl ether group: 61-63 ppm

[0138] Butyl ether group: 30-34 ppm

[0139] <Concentration of carbon (C14) from biomass>

[0140] For the concentration of biomass-derived carbon (C14) in alkyl etherified melamine resin (A), as described in ASTM D6866 04 (Standard Test Method for Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis), the sample is burned to produce CO2. The accurately quantified CO2 gas is loaded into an AMS (Accelerated Mass Spectrometry) device, and the amount of carbon with mass number 14, mass number 12, or mass number 13 is measured. This is distinguished by comparing it with the presence rate of carbon with mass number 14 in the atmosphere and petrochemicals.

[0141] [Manufacturing Example 1]

[0142] 126 g (1 mol) of melamine, 294 g (9 mol) of paraformaldehyde (92% formaldehyde concentration), 460 g (10 mol) of ethanol, and 0.04 g (1 mmol) of sodium hydroxide were added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube. The mixture was heated to reflux temperature. 1 g (5.8 mmol) of p-toluenesulfonic acid was added, and the first alkyl etherification reaction was carried out at reflux temperature. The mixture was then neutralized with 0.8 g (0.02 mol) of sodium hydroxide, and the ethanol was removed by distillation under reduced pressure. Another 1 g (5.8 mmol) of p-toluenesulfonic acid and 460 g (10 mol) of ethanol were added to complete the second alkyl etherification reaction. The mixture was then neutralized with 0.8 g (0.02 mol) of sodium hydroxide, and the ethanol was removed by distillation under reduced pressure. The mixture was then diluted with isobutanol until the non-volatile components reached 60% by weight, thus obtaining melamine resin (A-1).

[0143] The average molar ratio of alkyl ether groups to 1 mole of triazine ring in the obtained melamine resin (A-1) is 4.5, and the Mw is 1000.

[0144] [Manufacturing Examples 2-5]

[0145] As shown in Table 1, the type and amount of alcohol used were changed, and the melamine resins (A-2) to (A-4) and (A'-1) were produced in the same manner as melamine resin (A-1). The physical properties of the obtained resins are shown in Table 2.

[0146] [Table 1]

[0147] Table 1

[0148]

[0149] [Manufacturing Example 6]

[0150] 126 g (1 mol) of melamine, 163 g (5 mol) of paraformaldehyde (92% formaldehyde concentration), and 368 g (8 mol) of ethanol were added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube. The mixture was heated to reflux temperature. After hydroxymethylation at reflux temperature for 1 hour, 0.2 g (1.2 mmol) of p-toluenesulfonic acid was added, and alkyl etherification was carried out at reflux for 3 hours. The reaction product was then neutralized with triethanolamine, and the ethanol was removed by distillation under reduced pressure. The product was then diluted with isobutanol until the non-volatile components reached 60% by weight, thus obtaining melamine resin (A'-2).

[0151] The obtained melamine resin (A'-2) has an average molar ratio of alkyl ether groups to 1 mole of triazine ring of 1.8 and a Mw of 1,200.

[0152] [Manufacturing Example 7]

[0153] 126 g (1 mol) of melamine, 163 g (5 mol) of paraformaldehyde (92% formaldehyde concentration), 593 g (8 mol) of butanol, and 0.2 g (1.2 mmol) of p-toluenesulfonic acid were added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube. The mixture was then heated to reflux temperature. After hydroxymethylation at reflux temperature for 1 hour, an alkyl etherification reaction was carried out at reflux for 3 hours while simultaneously dehydrating the product. The reaction product was then neutralized with triethanolamine, and the butanol was removed by distillation under reduced pressure. The product was then diluted with isobutanol until the non-volatile components reached 60% by weight, thus obtaining melamine resin (A'-3).

[0154] The obtained melamine resin (A'-3) has an average molar ratio of alkyl ether groups to 1 mole of triazine ring of 2.2 and a Mw of 3,800.

[0155] [Table 2]

[0156] Table 2

[0157]

[0158] *Me = methyl ether, Et = ethyl ether, Bu = butyl ether

[0159] [Example 1]

[0160] 100 parts by weight of melamine resin (A-1) (value converted based on solid content, the same below) and 5 parts by weight of p-toluenesulfonic acid as acid catalyst (B) are mixed in toluene to obtain a compound liquid of a release coating agent composition with a solid content of 10% by weight.

[0161] Using a bar coater, the obtained compound solution was uniformly coated onto one side of an untreated PET film (thickness: 38 μm) serving as the substrate at 25°C / 80% RH. The resulting coating layer (uncured film) was then cured by heating and drying at 80°C for 1 minute, resulting in a release film with a 1.0 μm thick cured layer (release layer) laminated on the substrate.

[0162] [Examples 2-7, Comparative Examples 1-4]

[0163] Using the types of melamine resin, the release component (C) (polyester-modified hydroxyl-containing polysiloxane (manufactured by BYK Chemie Japan KK, trade name: BYK-370, weight average molecular weight: 5000)) or other components (trimethylolpropane as a binder) as described in Table 3, the same procedure as in Example 1 was followed to obtain the compounding liquid and the release film.

[0164] The methods for determining the physical properties of the complexing solutions and release films obtained in the above embodiments and comparative examples are as follows.

[0165] <Storage stability (low-temperature stability of the complex solution)>

[0166] The low-temperature stability of the complexed liquids obtained in Examples 1-7 and Comparative Examples 1-4 was evaluated visually based on the following criteria. The results are shown in Table 3.

[0167] ○: No complex components were precipitated after standing at 0℃ for 24 hours.

[0168] ×: After standing at 0℃ for 24 hours, the complex components precipitated out.

[0169] <Appearance of Coating Film (Cureable Coating Film)>

[0170] Based on the following criteria, the coating appearance of the release films obtained in Examples 1-7 and Comparative Examples 1-4 was evaluated visually. The results are shown in Table 3.

[0171] ◎: No whitening was observed in the membrane.

[0172] ○: This level is practically fine, but whitening was observed in a portion of the membrane.

[0173] ×: Whitening was observed throughout the membrane.

[0174] <Seam Fit (Seam Fit of Untreated PET)>

[0175] The release films obtained in Examples 1-7 and Comparative Examples 1-4 were subjected to a checkerboard peel test according to (JIS K 5600-5-6), and evaluated based on the following criteria. The results are shown in Table 3. It should be noted that cases where no peeling occurred in 100 squares are recorded as 100 / 100, and cases where all peeling occurred are recorded as 0 / 100.

[0176] ○: The number of parts where the substrate and coating adhere tightly after peeling is 100 / 100.

[0177] ×: The number of parts where the substrate and coating adhere tightly after peeling is 0 / 100 to 99 / 100.

[0178] Solvent resistance

[0179] The release films obtained in Examples 1-7 and Comparative Examples 1-4 were rubbed with gauze impregnated with methyl ethyl ketone, and the number of rubs until the substrate was exposed was evaluated based on the following criteria. The results are shown in Table 3.

[0180] ◎: Even after more than 80 rubs, the substrate will not be exposed.

[0181] ○: The substrate is exposed after 50 to 79 rubs.

[0182] ×: The substrate was exposed after 0 to 49 rubs.

[0183] <Peeling force>

[0184] On the peeling layer of the release films obtained in Examples 1-7 and Comparative Examples 1-4, a polyester adhesive tape (31B / manufactured by Nitto Denko Corporation) was pressed onto the test piece with one side under a load of 2 kg and stretched at a peeling speed of 0.3 m / min at an angle of 180 degrees. The peeling force (N / 25 mm) was calculated. The results are shown in Table 3.

[0185] [Table 3]

[0186]

[0187] Industrial availability

[0188] The thermosetting release coating composition containing alkyl etherified melamine resin obtained in this invention not only exhibits excellent peelability of the layer (cured layer) formed by coating and curing the composition, but also suppresses poor appearance of the coating film (cured coating film). Furthermore, it demonstrates excellent adhesion and solvent resistance even when cured at low temperatures. Therefore, for example, a release film comprising a release layer and a substrate, which are obtained as a cured layer according to one aspect of this invention, is useful in the production of ceramic green bodies that serve as raw materials for laminated ceramic capacitors, and in the production of transfer foil sheets for processing the surface of a transfer object. Additionally, the thermosetting release coating composition exhibits excellent storage stability, which is also a useful aspect.

Claims

1. A thermosetting release coating composition comprising an alkyl etherified melamine resin (A) and an acid catalyst (B). The alkyl ether group contained in the alkyl etherified melamine resin (A) includes an ethyl ether group, and the weight average molecular weight of the alkyl etherified melamine resin (A) is 500 to 1,100. The average molar ratio of alkyl ether groups to 1 mole of triazine ring in the alkyl etherified melamine resin (A) is 3 to 6.

2. The thermosetting release coating composition as described in claim 1, wherein, As an alkyl ether group contained in alkyl etherified melamine resin (A), it also contains a methyl ether group. The molar ratio of methyl ether group to ethyl ether group (methyl ether group) / (ethyl ether group) is less than 90 / 10.

3. The thermosetting release coating composition as described in claim 1, wherein, The acid catalyst (B) is p-toluenesulfonic acid.

4. The thermosetting release coating composition of claim 1, further comprising a release component (C).

5. The thermosetting release coating composition of claim 1, wherein, Based on ASTM D6866 04 Method B, the concentration of carbon from biomass in alkyl etherified melamine resin (A) is 20-100% of the total organic carbon.

6. The thermosetting release coating composition of claim 1, wherein, The content of alkyl etherified melamine resin (A) is 10 to 99 parts by weight relative to 100 parts by weight of solid components contained in the thermosetting release coating composition.

7. A laminate having a cured layer on at least one side of a substrate, said cured layer being formed from the thermosetting release coating composition of any one of claims 1 to 6.

8. The laminate as claimed in claim 7, wherein, The substrate is polyethylene terephthalate.

9. The laminate as claimed in claim 8, wherein, The substrate is untreated polyethylene terephthalate.

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