JP7223746B2 - Coating liquid for film formation and method for producing film-coated substrate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coating liquid for forming a releasable film on a base material such as resin, rubber or paper, and a method for producing a film-coated base material using this coating liquid.

A release film, a fixing belt, a release paper, and the like have a film having release properties formed on a base material such as resin, rubber, or paper.

Release films are used in various fields such as process films used in the manufacture of ceramic capacitors and the like, mounts for adhesive tapes, protective films for touch panels, and the like. A release film having a layer A (release layer) responsible for releasability and a layer B (substrate) responsible for heat resistance is known (see, for example, Patent Document 1). An acrylic resin or a silicone resin is used for the release layer.

Fixing belts are used in image forming apparatuses such as copiers and printers. The fixing belt is required to have releasability from toner and transfer paper. For this reason, fluorine-based resin is used for the film on the surface of the belt (see, for example, Patent Document 2). In Patent Document 2, a fluororesin layer having a heat of fusion of 28 mJ/mg or less is used for the release layer on the surface of the fixing belt. Polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and the like are used as raw materials for this fluororesin layer.

JP-A-2004-079567 JP 2003-114585 A

A film having releasability is required to further improve releasability. The release film described in Patent Document 1 does not have sufficient releasability because the release layer is an acrylic resin. On the other hand, a resin film containing fluorine has excellent releasability. However, since PTFE and PFA, which are thermoplastic fluororesins disclosed in Patent Document 2, are difficult to process, it is difficult to adjust the smoothness and unevenness of the film surface. Therefore, a thermoplastic film cannot provide sufficient releasability. Compared to thermoplastic fluororesins, thermosetting and UV-curable fluororesins can be processed relatively easily by dispersing them in a solvent. However, even if a film is formed on a base material using only a thermosetting or ultraviolet-curing fluororesin, releasability and adhesion to the base material are not sufficient.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a coating liquid that provides a film having excellent releasability and adhesion to a substrate.

A coating liquid for film formation according to the present invention contains a fluorine-based oligomer having a reactive group, a curable oligomer, and an organic solvent. Here, the solubility parameter (SP value) of the organic solvent is 11 (cal/cm ³ ) ^1/2 or less, the surface tension (ST _A ) of the fluorine-based oligomer is 22 mN/m or less, and the surface tension (ST _B ) is 28 mN/m or more and 32 mN/m or less, and the difference between these surface tensions (ST _B −ST _A ) is 7.5 mN/m or more. In the film formed using this coating liquid, the fluorine-based oligomer has a low surface tension, so that it is unevenly distributed on the surface side of the film (the interface on the film-attached substrate opposite to the substrate interface). As a result, fine unevenness (Wenzel structure) is formed on the surface of the film. Therefore, the coefficient of dynamic friction is lowered, and a film having excellent releasability can be obtained. On the other hand, since a relatively large amount of curable oligomer exists at the substrate interface, it has sufficient bonding strength with the substrate. Therefore, it is possible to obtain a film having good releasability and excellent adhesion.

Furthermore, the coating liquid is treated with at least one cluster forming agent selected from acrylic, acrylic silicone, silicone and fluorine surface modifiers, and the surface of the first inorganic oxide particles is treated with a surfactant. and first particles having a particle diameter of 10 to 300 nm.

With the coating liquid of the present invention, a film having excellent releasability and adhesion to a substrate can be obtained.

The coating liquid of the present invention contains a fluorine-based oligomer having a reactive group, a curable oligomer, and an organic solvent having a solubility parameter (SP value [(cal/cm ³ ) ^1/2 ]) of 11 or less. Here, the surface tension ST _A [mN/m] of the fluorine-based oligomer is 22 or less, and the surface tension ST _B [mN/m] of the curable oligomer is 28 or more and 32 or less. difference in surface tension is 7.5 mN/m or more.

In such a coating liquid, convection occurs due to volatilization of the organic solvent during drying. Since this convection causes part of the fluorine-based oligomers to move toward the film surface, the fluorine-based oligomers are unevenly distributed on the film surface. In addition, this convection forms fine unevenness (Wenzel structure) on the surface of the film. As a result, a film having excellent releasability can be obtained with one coat. In addition, since the fluorine-based oligomer is unevenly distributed on the film surface, a relatively large amount of the curable oligomer exists at the substrate interface. Therefore, the film has sufficient bonding strength with the substrate, and is excellent in adhesion to the substrate. If the surface tension of each oligomer does not satisfy the above relationship, the fluorine-based oligomer is less likely to be unevenly distributed on the surface of the film. Therefore, the releasability of the film cannot be sufficiently obtained. If the surface tension _STB of the curable oligomer is greater than 32, sufficient film adhesion may not be obtained. Incidentally, the surface tension of the fluorine-based oligomer is preferably 21 or less. Moreover, the surface tension of the fluorine-based oligomer is preferably 10 or more. The surface tension of the curable oligomer is preferably 29 or more and 31 or less. The difference between these is preferably 8.0 or more.

The SP value of the organic solvent contained in the coating liquid is preferably 11 or less. If it is not within this range, the compatibility between the fluorine-based oligomer and the organic solvent will be insufficient. Therefore, convection due to volatilization of the organic solvent during drying makes it difficult for the fluorine-based oligomer to move to the surface. As a result, the uneven distribution of the fluorine-based oligomer on the film surface is reduced, so that the film cannot be sufficiently released. The SP value can be obtained by the Fedors calculation method (RF Fedors, Polym. Eng. Sci., 14(2), 147-154 (1974))). Note that the SP value is more preferably 10.5 or less.

Furthermore, it is preferable to use a plurality of organic solvents having different SP values and boiling points. This maintains compatibility between the fluorine-based oligomer and the curable oligomer in the coating liquid. In addition, the evaporation rate of the organic solvent can be adjusted when the film coated with the coating liquid is dried. Therefore, it becomes easy to unevenly distribute the fluorine-based oligomer on the surface of the film, and at the same time, it becomes easy to maintain film formability on the substrate interface side. Furthermore, the SP value of the first organic solvent having the highest boiling point among the plurality of organic solvents is preferably 11 or less. At that time, an organic solvent having an SP value of greater than 11 may be included. When the SP value is 11 or less, the compatibility between the fluorine-based oligomer and the first organic solvent that evaporates last when the coating liquid is dried is improved. Therefore, convection generated by volatilization of the organic solvent facilitates movement of the fluorine-based oligomer to the surface of the film. As a result, a film in which the fluorine-based oligomer is unevenly distributed on the film surface is obtained, so that the release property of the film is excellent. At this time, the first organic solvent is preferably contained in the coating liquid in an amount of 100% by mass or more with respect to 100% by mass of the fluorine-based oligomer. This makes it easier to obtain a film in which the fluorine-based oligomer is unevenly distributed on the surface of the film. Moreover, it is more preferable to contain 500 mass % or more.

The coating liquid preferably contains a cluster forming agent and first particles. As a result, when the organic solvent evaporates during drying, the first particles interact with each other to form aggregates (clusters). Due to these clusters, an uneven shape (large undulations) is formed on the surface of the film. This allows the film to have excellent releasability. At this time, the first particles are preferably particles obtained by treating the first inorganic oxide particles having OH groups on the particle surface with a surfactant. This allows the first particles to maintain sufficient dispersibility in the coating liquid. Also, the average particle size of the first particles is preferably 10 to 300 nm. It is more preferably 10 to 120 nm. If the average particle diameter of the first particles is less than 10 nm, the size of the clusters obtained when drying the coating liquid later becomes small, and thus sufficient releasability may not be obtained. When the average particle size is larger than 300 nm, haze occurs in the film, the transparency of the film is lowered, and sufficient clusters are difficult to form. The average particle size of the particles is measured by dynamic light scattering using Zetasizer Nano ZS manufactured by Malvern. The cluster-forming agent is selected from acrylic, acrylsilicone, silicone and fluorine surface modifiers.

The coating liquid preferably further contains second particles in which a silane coupling agent is bonded to the surface of the second inorganic oxide particles. Thereby, a film having high hardness and abrasion resistance can be formed. At this time, the average particle diameter of the second particles is preferably 10 to 150 nm. It is more preferably 10 to 130 nm. When the average particle diameter of the second particles is less than 10 nm, the uniform dispersibility in the coating liquid may deteriorate, and sufficient hardness may not be obtained. If the average particle size is larger than 150 nm, haze occurs in the film and the transparency of the film is lowered. Also, the silane coupling agent preferably has a reactive group that reacts with the curable oligomer. As a result, the silane coupling agent bonds with the curable oligomer, thereby improving the hardness and abrasion resistance of the entire coating. Furthermore, it is preferable that the second particles are included in the solid content of the coating liquid in an amount of 1 to 60% by mass. It is more preferably 10 to 55% by mass. By containing the second particles in this range, a film having high hardness and abrasion resistance can be formed.

A film obtained using a coating liquid may be required to have heat resistance and conformability in addition to releasability when used in a fixing belt inside a copier. Followability is the resistance to bending when the base material is processed into a roll shape when a rubber base material or the like is used. It is also resistant to deformation when the rubber substrate is pushed during subsequent use. Selection of a curable oligomer is important in order to obtain a film having such followability. Resins such as acrylic monomers and polyfunctional urethane acrylate oligomers tend to form dense and hard films after curing. As a result, when the substrate is bent or pushed, the film may peel off from the substrate or cracks may occur. Therefore, it is not preferable as a curable oligomer. Preferably, the curable oligomer is di- to tetra-functional. Thereby, a film with high conformability can be obtained. Urethane (meth)acrylate oligomers, silicone (meth)acrylates, and sol-gel thermosetting types are preferred. By selecting these, the releasability of the film does not deteriorate in applications where the film is exposed to high temperatures (about 180° C.). Under these conditions, acrylic monomers are not preferred due to their low heat resistance. Furthermore, the curable oligomer is more preferably at least one selected from urethane (meth)acrylate oligomers, epoxy acrylates and acrylate oligomers having no urethane bond. The urethane (meth)acrylate oligomer is more preferably an ester-modified urethane (meth)acrylate oligomer or a polar group-introduced urethane (meth)acrylate oligomer. Such a curable oligomer also bonds with a fluorine-based oligomer because the reactive group of the fluorine-based oligomer is an acryloyl group or a methacryloyl group. Therefore, the functions of the film (mold releasability, adhesion, heat resistance, conformability) are fully exhibited. A layer formed of such a curable oligomer functions as an elastic layer on the fixing belt. Therefore, when the fixing belt presses against the printing paper, the film sufficiently follows the fixing belt even if the fixing belt is deformed by the pushing pressure. After that, the film grips the printing paper even when the printed printing paper is conveyed, so that the discharge (paper feeding) performance can be improved.

Each component of the coating liquid will be described in detail below.

<Fluorine-based oligomer>
The fluorine-based oligomer preferably has a reactive group that bonds with the curable oligomer. If the fluorine-based oligomer does not have a reactive group, it bleeds out from the film surface without being integrated with the film. Therefore, whitening of the film is induced and releasability is deteriorated, thereby reducing reliability. The reactive group may be appropriately selected depending on whether the curable oligomer is a thermosetting oligomer, an ultraviolet curable oligomer, or an electron beam curable oligomer. For example, reactive groups that react with UV-curable oligomers include acryloyl groups and methacryloyl groups. Examples of fluorine-based oligomers having such reactive groups include OPTOOL DAC-HP manufactured by Daikin Industries, Ltd., MEGAFACE RS series manufactured by DIC Corporation, Fluorosurf series manufactured by Fluoro Technology Co., Ltd., and the like. .

The average molecular weight of the fluorine-based oligomer is preferably 1,000 to 10,000. When the fluorine-based monomer is used instead of the fluorine-based oligomer, the surface tension ST _A [mN/m] is higher than 22, and a sufficient difference in surface tension from the curable oligomer cannot be obtained. In this case, the fluoromonomer is less likely to be unevenly distributed on the film surface side, and sufficient releasability cannot be obtained. When a fluorine-based polymer is used instead of a fluorine-based oligomer, the adhesion to the substrate may deteriorate.

The fluorine-based oligomer is preferably contained in the solid content of the coating liquid in an amount of 0.1 to 30% by mass. Within this range, it is easy to obtain a film with excellent releasability. The fluorine-based oligomer is more preferably contained in the solid content of the coating liquid in an amount of 0.5 to 25% by mass, more preferably 0.7 to 20% by mass. If it is less than 0.1% by mass, sufficient releasability cannot be obtained. If it is more than 30% by mass, the film may whiten or the fluorine component may bleed out from the surface of the film, thereby reducing the reliability of the film.

<Curable oligomer>
As the curable oligomer, any one of a thermosetting oligomer, an ultraviolet curable oligomer, and an electron beam curable oligomer can be used without particular limitation. The average molecular weight of the curable oligomer is preferably 1,000-10,000. 1000 to 8000 are more preferred. 1000 to 5000 are more preferred. When a curable monomer is used instead of a curable oligomer, the compatibility between the fluorine-based oligomer and the curable monomer is too high, so that the fluorine-based oligomer is less likely to be unevenly distributed on the film surface, and the release property of the film is sufficient. I can't get it. Further, when a curable polymer is used instead of the curable oligomer, the reactivity is low, and therefore sufficient adhesion to the substrate may not be obtained.

The curable oligomer is preferably contained in an amount of 10 to 99% by mass in the solid content of the coating liquid. Within this range, the curable oligomer and the substrate have sufficient bonding strength, so that a film with excellent adhesion to the substrate can be easily obtained. If the curable oligomer content is less than 10% by mass, the adhesion between the film and the substrate may deteriorate. If the content is more than 99% by mass, sufficient releasability may not be obtained. Further, it is more preferably 15 to 97% by mass.

Examples of the curable oligomer include NK Oligo UA-512 manufactured by Shin-Nakamura Chemical Co., Ltd., EBECRYL 8402 and EBECRYL 3708 manufactured by Daicel Allnex Co., Ltd., and Shiko UV-7550B manufactured by Nippon Synthetic Chemical Industry Co., Ltd. be able to. A film obtained using a coating liquid containing such a curable oligomer is excellent in releasability and adhesion to a substrate, as well as in heat resistance and conformability.

<Organic solvent>
The organic solvent is preferably contained so that the coating liquid has a solid content concentration of 10 to 90% by mass. More preferably, it is contained in an amount of 15 to 85% by mass. When the solid content is lower than 10% by mass, it is difficult to apply uniformly when obtaining a film of 5 μm or more. Therefore, film unevenness and poor appearance may occur. If it is more than 90% by mass, the dispersibility of the fluorine-based oligomer, the curable oligomer and the inorganic oxide particles in the coating liquid is lowered, and the storage stability of the coating liquid is deteriorated.

Organic solvents with an SP value of 11 or less include, for example, methyl isobutyl ketone (SP value 8.3), methyl ethyl ketone (SP value 9.3), propylene glycol monomethyl ether (SP value 10.2), diethyl ether (SP value 9. 0), acetone (SP value 9.1), methylcyclohexanone (SP value 10.0), and the like.

<Cluster Forming Agent and First Particle>
The cluster forming agent is preferably contained in an amount of 5 to 150 mass % as a solid content with respect to 100 mass % of the first inorganic oxide particles. Within this range, when the coating liquid dries, the cluster-forming agent interacts with the first particles to form clusters of the first particles in the film. Starting from these clusters, an uneven shape (large undulations) is formed on the film surface, so a film with excellent releasability can be easily obtained. Further, it is more preferably 5 to 100% by mass. If the amount of the cluster-forming agent is less than 5% by mass, the interaction between the cluster-forming agent and the first particles is insufficient, so that clusters of a size sufficient to form the uneven shape cannot be obtained, resulting in poor releasability. decreases. If it is more than 150% by mass, the stability of the paint deteriorates.

Examples of acrylic surface conditioners include Disparon UVX-271, UVX-272, UVX-3750, UVX-35 and UVX-36 manufactured by Kusumoto Kasei Co., Ltd. Examples of acrylic silicone surface conditioners include Disparon NSH-8430HF, LHP-810, NSF-8363, UVX-2280 and UVX-2285 manufactured by Kusumoto Kasei Co., Ltd. Examples of silicone-based surface conditioners include LS-430, LS-220, LS-240, LS-260, LS-280 and LS-480 manufactured by Kusumoto Kasei Co., Ltd. Examples of fluorine-based surface conditioners include F-555 and F-558 manufactured by DIC Corporation, and Futergent 208G and 212P manufactured by Neos Corporation.

<First particle>
As for the shape of the first inorganic oxide particles contained in the first particles, known shapes such as spherical, rod-like, chain-like, fibrous, confetti-like and hollow can be used. Spherical particles are particularly preferred. Also, the first inorganic oxide particles are preferably oxides containing at least one element selected from silicon, aluminum, zirconium, titanium, antimony, tin, and indium. In particular, particles containing silica as a main component are preferred.

The first particles are preferably surface-treated with a surfactant in a solid content of 1 to 20 parts by mass with respect to 100 parts by mass of the first inorganic oxide particles. If the amount is less than 1 part by mass, the first particles cannot maintain their dispersibility in the coating liquid, possibly causing aggregation. If the amount is more than 20 parts by mass, the dispersibility becomes too high, and cluster formation becomes difficult when the organic solvent evaporates during drying. Further, it is more preferable that the surface is treated with a surfactant of 3 to 10 parts by mass as a solid content. Examples of surfactants include Amiradin C-1802, Plysurf A-212E, and Plysurf AL manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.

The first particles are preferably contained in an amount of 1 to 50% by mass in the solid content of the coating liquid. Within this range, as the concentration of the first particles increases as the organic solvent volatilizes, the interaction between the first particles is strengthened by the action of the cluster forming agent. This creates clusters (heterogeneous domains). With these clusters as starting points, uneven shapes (large undulations) are formed on the surface of the film, and sufficient releasability can be exhibited. If the amount of the first particles is less than 1%, clusters having a size sufficient to form the uneven shape are not formed, and excellent releasability cannot be obtained. If the first particles are more than 50%, the conformability to the film is lowered. Further, it is more preferable that the first particles are contained in the solid content of the coating liquid in an amount of 2 to 30% by mass.

<Second particle>
As for the shape of the second inorganic oxide particles contained in the second particles, known shapes such as spherical, rod-like, chain-like, fibrous, confetti-like and hollow can be used. At this time, the shape of the second inorganic oxide particles may be the same as or different from that of the first inorganic oxide particles. The shape of the second inorganic oxide particles is preferably spherical particles. Also, the second inorganic oxide particles are preferably oxides containing at least one element selected from silicon, aluminum, zirconium, titanium, antimony, tin, and indium. At this time, an oxide containing the same element as that of the first inorganic oxide particles or an oxide containing a different element may be used. In particular, particles containing silica as a main component are preferred.

The silane coupling agent that bonds to the surface of the second inorganic oxide particles preferably has a functional group that has a high affinity with the functional group of the curable oligomer. Therefore, the silane coupling agent may be appropriately selected depending on whether the curable oligomer is a thermosetting oligomer, an ultraviolet curable oligomer, or an electron beam curable oligomer.

The second particles are preferably surface-treated with a silane coupling agent in a solid content of 1 to 50% by mass based on 100% by mass of the second inorganic oxide particles. Within this range, the silane coupling agent and the curable oligomer react sufficiently, so that a film with high hardness and abrasion resistance can be easily obtained. If the amount of the silane coupling agent is less than 1% by mass, the bonding with the curable oligomer will be insufficient, resulting in reduced hardness and abrasion resistance of the entire film. If it is more than 50% by mass, the silane coupling agent monomer or oligomer that has not reacted with the particles may bleed out to the film surface, resulting in a decrease in transparency. Further, it is more preferable that the surface is treated with 5 to 30 parts by mass of a silane coupling agent as a solid content.

<Other ingredients>
Other components (curing catalyst, photopolymerization initiator, leveling agent, etc.) are added to the coating liquid as necessary.

When the curable oligomer is a thermosetting oligomer, a curing catalyst is preferably added to the coating liquid. A known curing catalyst can be used without particular limitation. Examples of acids include hydrochloric acid, phosphoric acid, nitric acid, p-toluenesulfonic acid and the like. Examples of metal salts of organic acids include sodium acetate, zinc naphthenate, cobalt naphthenate, zinc octylate and the like. Examples of perchloric acids include tin octylate, perchloric acid, ammonium perchlorate, and magnesium perchlorate. At this time, the curing catalyst is preferably contained in the coating liquid in an amount of 1 to 20% by mass. It is more preferably contained in an amount of 2 to 15% by mass. If the amount of the curing catalyst is less than 1% by mass, the curing reaction may not progress, resulting in insufficient curing. If it is more than 20% by mass, there is a possibility that the film will contain too much curing catalyst and the hardness and abrasion resistance of the film as a whole will decrease.

When the curable oligomer is an ultraviolet curable oligomer, a photopolymerization initiator is added to the coating liquid. A known photopolymerization initiator can be used without particular limitation. For example, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)2,4,4-trimethyl-pentylphosphine oxide, 2-hydroxy-methyl-2-methyl- Phenyl-propane-1-ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-1-[4-(methylthio)phenyl]- and 2-morpholinopropan-1-one. At this time, the photopolymerization initiator is preferably contained in the solid content of the coating liquid in an amount of 1 to 20% by mass. It is more preferably contained in an amount of 2 to 15% by mass. If the amount of the photopolymerization initiator is less than 1% by mass, the curing reaction may not proceed and the curing may be insufficient. If it is more than 20% by mass, the film may contain too much photopolymerization initiator and the hardness and abrasion resistance of the film as a whole may be lowered.

The coating liquid may contain a leveling agent in order to adjust the wettability with the substrate, the leveling property of the film surface, and the like. The leveling agent preferably contains one selected from acrylic, acrylic silicone, silicone, and fluorine. However, the leveling agent is preferably different from the one used for the cluster forming agent. When the cluster-forming agent and the leveling agent are different, the respective effects of the cluster-forming agent and the leveling agent are sufficiently exhibited. The leveling agent is preferably contained in an amount of 0.05 to 5.0% by mass based on the solid content of the coating liquid. It is more preferably contained in an amount of 0.1 to 2.5% by mass. When the amount of the leveling agent is less than 0.05% by mass, the leveling effect is not sufficiently exhibited, and film unevenness and poor appearance may occur. If it is more than 5.0% by mass, the leveling agent is present in the film and also at the interface between the substrates, possibly causing deterioration in hardness, abrasion resistance, and adhesion of the entire film.

The film-coated substrate will be described in detail below.

<Base material with film>
The film-coated substrate can be obtained by coating the substrate with the coating liquid, drying it, and then curing it. By curing the coating liquid, the fluorine-based oligomer and the curable oligomer contained in the coating liquid are cured to become a fluorine-based resin and a cured resin, respectively. Drying is performed by heating to, for example, 50 to 150° C. to evaporate and remove the solvent. When the curable oligomer in the coating liquid is a thermosetting oligomer, the coated base material is heated to 80 to 200° C. to cure after drying. In the case of an ultraviolet curable oligomer, the coating substrate is irradiated with ultraviolet rays after drying to be cured. In the case of an electron beam-curable oligomer, the coating substrate is irradiated with an electron beam after drying to be cured. Irradiation with ultraviolet rays or electron beams is preferably performed in a nitrogen atmosphere.

The film of the film-attached substrate contains a fluororesin and a curable resin, and the fluororesin is unevenly distributed on the surface side of the film. The degree of uneven distribution of the fluororesin can be estimated by measuring the ratio of fluorine atoms using X-ray photoelectron spectroscopy. From the ratio (X _o /X 300 ) of the ratio of fluorine atoms on the surface of the film (X _o [%]) to the ratio of fluorine atoms (X ₃₀₀ [%]) at a depth of ₃₀₀ nm from the surface of the film, , the degree of uneven distribution of fluorine atoms can be seen. If this ratio is 1.1 to 300 and _X0 is 5 to 60, the film will have excellent releasability. This ratio is preferably 1.5-200, more preferably 1.5-150. X ₀ is preferably 10-50, more preferably 20-40. Within this range, the film has excellent releasability. When there are no first particles, second particles or clusters in the film, the ratio of fluorine atoms is the number of fluorine atoms with respect to the total number of atoms of carbon, oxygen, nitrogen and fluorine. When primary particles, secondary particles or clusters are present in the film, the ratio of fluorine atoms is the number of fluorine atoms with respect to the total number of atoms of carbon, oxygen, silicon, nitrogen and fluorine. In order to obtain the atomic proportions of carbon, oxygen, silicon, nitrogen, and fluorine, the peaks of C1s, O1s, Si2p, N1s, and F1s are measured, respectively. The energy intensity of the C1s peak is observed at 284-286 eV. O1s is observed at 532-534 eV, Si2p at 103-104 eV, N1s at 398-400 eV, and F1s at 687-689 eV. Analysis in the depth direction from the surface of the film is measured while performing Ar etching. The Ar etching was performed under the condition that etching speed of the silicon plate was 3 nm/min. Ar etching was performed for 100 minutes in the measurement at a depth of 300 nm from the surface of the film. Further, the ratio (X _o /X ₁₀₀ ) between X _o [%] and the ratio of fluorine atoms (X ₁₀₀ [%]) at a depth of 100 nm from the surface of the film is in the range of 1.0 to 50. preferable. It is more preferably in the range of 1.2-25. Within this range, the film has excellent releasability. Furthermore, this ratio is preferably less than the ratio of X _o to X ₃₀₀ (X _o /X ₃₀₀ ).

The film-coated substrate has an average surface roughness (R _a ) of 1 to 50 nm and a maximum height difference (R _max ) of 30 to 300 nm, and forms fine unevenness (Wenzel structure). is preferred. Within such a range, a film having excellent releasability can be obtained.

It is preferable that the film-coated base material has unevenness (large undulations) formed on the surface of the film due to clusters of inorganic oxide particles. Thereby, higher releasability can be obtained. At this time, the clusters in the film are preferably formed from first particles having a particle diameter of 10 to 300 nm. The size of the formed cluster particles is preferably 240 to 2400 nm. If the thickness is smaller than 240 nm, the unevenness (undulation) formed on the surface of the film is reduced, resulting in poor releasability. If it is larger than 2400 nm, the followability of the film becomes poor. At this time, it is preferable that the film has an average surface roughness (R _a ) of 50 to 1000 nm and a maximum height difference (R _max ) of 300 to 5000 nm. Such a film-coated substrate can be obtained by using a coating liquid containing a cluster forming agent and first particles. _Ra and _Rmax can be adjusted by adjusting the average particle diameter of the first particles, the amount of the first particles added, the amount of the cluster forming agent added, and the like. More preferably, R _a is between 50 and 600 nm and R _max is between 500 and 4000 nm.

It is preferable that the film of the film-coated substrate further contains second particles in which a silane coupling agent is bonded to the surface of the second inorganic oxide particles. This improves the abrasion resistance and hardness of the film-coated substrate. At this time, the particle diameter of the second particles is preferably 10 to 150 nm. Furthermore, the silane coupling agent is preferably bound to the curable oligomer. This further improves the abrasion resistance and hardness of the film-coated substrate.

The elastic modulus of the film of the film-attached substrate is preferably in the range of 50-2000. If the modulus of elasticity is lower than 50, it is difficult for the coating film to return to its original state after it is pushed in in the case of a rubber substrate, resulting in poor paper feedability. If it is higher than 2000, the repulsion when pushed is strong and the followability is deteriorated. Moreover, since the gripping property is lowered, the paper feeding property is deteriorated. At this time, the dynamic friction coefficient is preferably in the range of 0.05 to 0.4. When the coefficient of dynamic friction is within this range, a film-coated substrate having excellent releasability can be obtained.

The substrate used for the film-attached substrate is not particularly limited. For example, silicone rubber, polyethylene terephthalate (PET), triacetyl cellulose (TAC), paper, synthetic resin film, synthetic fiber cloth and the like can be used.

The shape of the substrate is not particularly limited. For example, endless belts, films, rolls, plates and the like can be used.

A method of applying the coating liquid to the substrate is not particularly limited. For example, a bar coater method, a dip method, a spray method, a spinner method, a roll coat method, a gravure coat method, a slit coat method, a pressure coating method, or the like can be used.

The average film thickness of the film of the film-coated substrate can be appropriately selected according to the application. In particular, the average film thickness is preferably 1 to 30 μm.

Since the film-coated substrate has high releasability, it can be used for applications such as release films, release paper, and fixing belts and fixing rolls of image forming apparatuses.

Hereinafter, embodiments of the present invention will be described in detail.

[Example 1]
<Preparation of coating liquid>
4.00 g of a fluorine-based oligomer having a reactive group (Megafac RS-90 manufactured by DIC Corporation, solid content concentration 10.0% by mass), and a curable oligomer (NK Oligo UA-512 manufactured by Shin-Nakamura Chemical Co., Ltd., solid content concentration 100% by mass) 39.60 g, an organic solvent 53.00 g, a leveling agent (Disparon NSH-8430HF manufactured by Kusumoto Kasei Co., Ltd., solid content concentration 10.0% by mass) 1.00 g, a photopolymerization initiator (IGM 2.40 g of Omnirad 184 (solid content concentration: 100% by mass) manufactured by Co., Ltd. was mixed to prepare a coating liquid having a solid content concentration of 42.5% by mass. As organic solvents, 40.80 g of methyl isobutyl ketone (MIBK), 6.90 g of propylene glycol monomethyl ether (PGME), and 5.30 g of acetone were used. The respective boiling points are MIBK: 116°C, PGME: 120°C, and acetone: 56°C. The SP value of PGME, which has the highest boiling point among them, is 10.2.

Table 1 shows the properties of the oligomer and the organic solvent that constitute the coating liquid. The surface tension (ST _A ) of the fluorine-based oligomer and the surface tension (ST _B ) of the curable oligomer were measured by the following methods.

(Measurement of surface tension)
The solid content concentration of the fluorine-based oligomer was adjusted to 0.1% by mass using PGME. The surface tension ST _A of this sample was measured at a temperature of 25° C. by the plate method (Wilhelmy method) using an automatic surface tensiometer (CBVP-A3 manufactured by Kyowa Interface Science Co., Ltd.). The solid content concentration of the curable oligomer was adjusted to 50% by mass using PGME. Using this sample, surface tension ST _B was measured in the same manner as ST _A.

Next, this coating liquid was applied to two types of substrates (silicone rubber and PET) to prepare film-coated substrates.

<Silicone rubber substrate>
The coating liquid was applied to silicone rubber having a thickness of 2 mm by a bar coater method (#30) and dried at 80° C. for 120 seconds. After that, it was irradiated with ultraviolet rays of 300 mJ/cm ² in an N ₂ atmosphere. Thus, a film-coated base material was obtained.

<PET base material>
The coating liquid was applied to a 188 μm-thick PET film with an easily adhesive layer (A4300 manufactured by Toyobo Co., Ltd.) by a bar coater method (#30) and dried at 80° C. for 120 seconds. After that, it was irradiated with ultraviolet rays of 300 mJ/cm ² in an N ₂ atmosphere. Thus, a film-coated base material was obtained.

Tables 2 and 3 show the evaluation results of these film-coated substrates. Each item was measured and evaluated by the following methods. Examples and comparative examples, which will be described later, were similarly evaluated.

(average film thickness)
The average film thickness was measured with a digital gauge (ST-0230 manufactured by Ono Sokki Co., Ltd.).

(Releasability)
A cellophane tape with a width of 18 mm (manufactured by Nichiban Co., Ltd.) was attached to the film of the film-coated substrate with a length of 20 mm, and the tape was peeled off with a finger, and the ease of peeling was evaluated according to the following evaluation criteria.
Evaluation criteria:
Peel off without resistance: ◎
There is a little resistance, but it can be easily peeled off: ○
There is resistance, but it can be peeled off: △
There is resistance, and if you pull it up strongly, it will come off : ×

(Followability)
The film-coated substrate was bent up and down 180 degrees, and the presence or absence of cracks in the film and peeling at the interface between the film and the substrate was evaluated according to the following evaluation criteria.
Evaluation criteria:
Cracks and interfacial peeling do not occur even if the film-coated substrate is bent up and down 180 degrees 100 times: ◎
Cracks and interfacial peeling do not occur even if the film-coated substrate is bent up and down 180 degrees 10 times: ○
Cracks and interfacial peeling occur when the film-coated substrate is bent up and down 180 degrees 10 times : △
Cracks and interfacial peeling occur when the film-coated substrate is bent once up and down 180 degrees: ×

(Adhesion)
A knife was used to make 100 squares by making 11 parallel scratches on the film on the film-coated substrate at intervals of 1 mm. After adhering a cellophane tape to this, the cellophane tape is peeled off. The number of squares remaining without peeling of the film was counted and evaluated according to the following evaluation criteria.
Evaluation criteria:
Number of remaining squares 100: ◎
Number of remaining squares 90 to 99: ○
Number of remaining squares 85 to 89: △
Number of remaining squares 84 or less: ×

(heat resistance test)
Releasability, adhesion, and conformability were evaluated using a measurement sample obtained by placing the film-coated substrate in a dryer at 180° C. for 10 hours.

(R _a , R _max )
An atomic force microscope (AFM) (manufactured by Bruker Co., Ltd.: Dimension 3100) was used to measure the average roughness (R _a ) and maximum height difference (R _max ) of a 50 μm square film surface.

(Pencil hardness)
Measured with a pencil hardness tester according to JIS-K-5600.

(elastic modulus)
In accordance with JIS K7161:1994, the measurement was performed at a temperature of 23° C. and a humidity of 50% at a chuck distance of 40 mm and a tensile speed of 200 mm/min (sample size: length 100 mm×width 15 mm).

(dynamic friction coefficient)
Using Tribostation Type 32 (Shinto Kagaku Co., Ltd.), place the coating film on the pedestal, place a vertical load of 200 g on a jig of 1.1 cmφ wrapped with flannel cloth, and sample at a sampling speed (1 m / min) of 50 Reciprocating rubbing, the dynamic friction coefficient after 50 reciprocating motions was taken as the measured value.

(Measurement of X-ray photoelectron spectroscopy)
Using X-ray photoelectron spectroscopy (XPS) (manufactured by Thermo Fisher Scientific (former VG): Escalab 220i-XL), the film surface and the ratio of fluorine atoms were measured at depths of 100 and 300 nm from the film surface. . Each peak of carbon, oxygen, silicon, nitrogen, and fluorine was measured, and the ratio of the number of atoms to the total number of atoms was measured. Table 4 shows the results.

[Example 2]
As the fluorine-based oligomer, 2.00 g of FS-7024 (solid concentration: 20.0% by mass) manufactured by Fluorotechnology was used. A coating liquid was prepared in the same manner as in Example 1 except for this.

[Example 3]
As the curable oligomer, EBECRYL 3708 (solid concentration: 100% by mass) manufactured by Daicel Allnex was used. A coating liquid was prepared in the same manner as in Example 1 except for this.

[Example 4]
The organic solvent was changed to 47.7 g of MIBK and 5.3 g of acetone without adding PGME. A coating liquid was prepared in the same manner as in Example 1 except for this.

[Example 5]
A fluorine-based oligomer having a reactive group (DIC Megafac RS-90, solid content concentration 10.0% by mass) 40.00 g, and a curable oligomer (NK Oligo UA-512 manufactured by Shin-Nakamura Chemical Co., Ltd., solid concentration 100% by mass) 16.00 g, organic solvent 41.80 g, leveling agent (Disparon NSH-8430HF manufactured by Kusumoto Kasei Co., Ltd., solid content concentration 10.0% by mass) 1.00 g, photopolymerization initiator (IGM 1.20 g of Omnirad 184 (solid content concentration: 100% by mass) manufactured by Co., Ltd. was mixed to prepare a coating liquid having a solid content concentration of 21.3% by mass. As organic solvents, 32.20 g of MIBK, 5.40 g of PGME, and 4.20 g of acetone were used.

[Example 6]
Methanol dispersion containing silica particles (first inorganic oxide particles) having an average particle diameter of 120 nm (ELCOM V-8901 manufactured by Nikki Shokubai Kasei Co., Ltd., solid content concentration 20.5% by mass) 100 g, a surfactant (first Amiradin C-1802 manufactured by Ichikogyo Seiyaku Co., Ltd. (solid concentration: 100% by mass) was mixed with 1.03 g, and then stirred at 50 ° C. for 20 hours to coat the surface of the first inorganic oxide particles with a surfactant. processed. Thereafter, the solvent was replaced with MIBK using a rotary evaporator to obtain a dispersion liquid (1) of first particles having an average particle diameter of 120 nm (solid concentration: 21.3% by mass).

100 g of a methanol dispersion of silica alumina particles (second inorganic oxide particles) having an average particle diameter of 12 nm (OSCAL1132 manufactured by Nikki Shokubai Kasei Co., Ltd., solid content concentration 40.5% by mass), and γ-meth as a silane coupling agent. 6.08 g of acrylooxypropyltrimethoxysilane (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd., solid content concentration 100% by mass), 8.8 g of ultrapure water, and 0.4 g of 5% aqueous ammonia were mixed. After that, the mixture was stirred at 50° C. for 6 hours to bond the silane coupling agent to the surfaces of the second inorganic oxide particles. Thereafter, the solvent was replaced with MIBK using a rotary evaporator to obtain a dispersion liquid (2) of second particles having an average particle diameter of 12 nm (solid concentration: 46.6% by mass).

9.76 g of the first particle dispersion (1), 14.81 g of the second particle dispersion (2), and a fluorine-based oligomer having a reactive group (Megafac RS-90 manufactured by DIC Corporation, solid content concentration 10 .0 mass%) 4.00 g, a curable oligomer (NK Oligo UA-512 manufactured by Shin-Nakamura Chemical Co., Ltd.) 32.00 g, an organic solvent 27.79 g (MIBK 24.45 g, PGME 3.34 g), and a cluster forming agent (Disparon LHP-810 manufactured by Kusumoto Chemicals Co., Ltd., solid content concentration 10.0% by mass) 5.00 g, a leveling agent (Disparon NSH-8430HF manufactured by Kusumoto Chemicals Co., Ltd., solid content concentration 10.0% by mass) 4.72 g, 1.92 g of a photopolymerization initiator (OMNIRAD 184 manufactured by IGM) was mixed to prepare a coating liquid having a solid concentration of 44.3% by mass. Table 5 shows the physical properties of the first particles and the second particles. In addition, the particle size in the film and the minimum and maximum values of clusters were measured by the following method. These measurement results are shown in Table 6.

(Particle size in film)
The coating film was embedded in epoxy resin, cross-sectionally processed with a microtome, and observed with a transmission electron microscope (FE-TEM HF-200 manufactured by Hitachi High-Tech Fielding Co., Ltd.), and the first particles, second particles, and clusters in the film were observed. measured the size.

[Example 7]
100 g of a methanol dispersion of silica alumina particles (first inorganic oxide particles) having an average particle diameter of 12 nm (OSCAL1132 manufactured by Nikki Shokubai Kasei Co., Ltd., solid content concentration 40.5% by mass), and a surfactant (Daiichi Kogyo Seiyaku After mixing 2.03 g of Amiradin C-1802) manufactured by Co., Ltd., the mixture was stirred at 50° C. for 20 hours to treat the surfaces of the first inorganic oxide particles with a surfactant. Thereafter, the solvent was replaced with MIBK using a rotary evaporator to obtain a dispersion liquid (solid content concentration: 41.7% by mass) of first particles having an average particle diameter of 12 nm.

A coating liquid was prepared in the same manner as in Example 6 using the dispersion liquid of the first particles according to the present example. However, the amount of the dispersion of the first particles was 4.94 g, and the amount of MIBK was 29.27 g.

[Example 8]
The amount of clustering agent was 1.80 g and the amount of MIBK was 27.65 g. A coating liquid was prepared in the same manner as in Example 6 except for this.

[Example 9]
The amount of clustering agent was 20.0 g and the amount of MIBK was 12.28 g. A coating liquid was prepared in the same manner as in Example 6 except for this.

[Example 10]
100 g of a methanol dispersion of silica sol (ELCOM V-8901 manufactured by Nikki Shokubai Kasei Co., Ltd., average particle diameter 120 nm, solid content concentration 20.5% by mass) as the second inorganic oxide particles, and γ-methacrylate as a silane coupling agent. After mixing 6.08 g of looxypropyltrimethoxysilane (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.), 8.80 g of ultrapure water, and 0.40 g of 5% aqueous ammonia, the mixture was stirred at 50° C. for 6 hours. Then, the silane coupling agent was bound to the surface of the second inorganic oxide particles. Thereafter, the solvent was replaced with MIBK using a rotary evaporator to obtain a dispersion of second particles (solid content concentration: 46.6% by mass) having an average particle size of 120 nm.

A coating liquid was prepared in the same manner as in Example 6 using the dispersion liquid of the second particles according to this example.

[Example 11]
9.76 g of the first particle dispersion (1) of Example 6, 29.63 g of the second particle dispersion (2), and a fluorine-based oligomer having a reactive group (Megafac RS-90 manufactured by DIC, Solid content concentration 10.0% by mass) 10.00 g, curable oligomer (NK Oligo UA-512 manufactured by Shin-Nakamura Chemical Co., Ltd.) 6.00 g, organic solvent 19.54 g (MIBK 12.50 g, PGME 7.04 g) , a cluster forming agent (Disparon LHP-810 manufactured by Kusumoto Chemical Co., Ltd.) 20.00 g, a leveling agent (Disparon NSH-8430HF manufactured by Kusumoto Chemical Co., Ltd.) 4.72 g, and a photopolymerization initiator (OMnirad 184 manufactured by IGM) 0.36 g were mixed to prepare a coating liquid having a solid concentration of 25.7% by mass. Using this coating liquid, a film-coated substrate was produced in the same manner as in Example 1, except that the bar coater was changed to #50.

[Example 12]
7.32 g of the first particle dispersion (1) of Example 6, 11.11 g of the second particle dispersion (2), and a fluorine-based oligomer having a reactive group (Megafac RS-90 manufactured by DIC Corporation, Solid content concentration 10.0% by mass) 30.00 g, 24.00 g of curable oligomer (NK Oligo UA-512 manufactured by Shin-Nakamura Chemical Co., Ltd.), 16.41 g of organic solvent (MIBK 13.00 g, PGME 3.41 g) , a cluster forming agent (Disparon LHP-810 manufactured by Kusumoto Chemicals Co., Ltd.) 5.00 g, a leveling agent (Disparon NSH-8430HF manufactured by Kusumoto Chemicals Co., Ltd.) 4.72 g, and a photopolymerization initiator (OMnirad 184 manufactured by IGM) 1.44 g were mixed to prepare a coating liquid having a solid concentration of 36.2% by mass. Using this coating liquid, a film-coated substrate was produced in the same manner as in Example 1, except that the bar coater was changed to #40.

[Example 13]
43.90 g of the first particle dispersion (1) of Example 6, 12.59 g of the second particle dispersion (2), and a fluorine-based oligomer having a reactive group (Megafac RS-90 manufactured by DIC, Solid content concentration 10.0% by mass) 2.00 g, 15.90 g of curable oligomer (NK Oligo UA-512 manufactured by Shin-Nakamura Chemical Co., Ltd.), 13.93 g of organic solvent (MIBK 10.00 g, PGME 3.93 g) , a cluster forming agent (Disparon LHP-810 manufactured by Kusumoto Chemicals Co., Ltd.) 5.00 g, a leveling agent (Disparon NSH-8430HF manufactured by Kusumoto Chemicals Co., Ltd.) 4.72 g, and a photopolymerization initiator (OMnirad 184 manufactured by IGM) 0.95 g were mixed to prepare a coating liquid having a solid concentration of 32.2% by mass. Using this coating liquid, a film-coated substrate was produced in the same manner as in Example 1, except that the bar coater was changed to #40.

[Comparative Example 1]
As a fluorine-based oligomer having a reactive group, 1.00 g of MEGAFACE RS-75 (solid concentration: 40.0% by mass) manufactured by DIC, and 43.80 g of MIBK were used. A coating liquid was prepared in the same manner as in Example 1 except for this.

[Comparative Example 2]
Light acrylate DPE-6A manufactured by Kyoeisha Chemical Co., Ltd. was used as the curable oligomer. A coating liquid was prepared in the same manner as in Example 1 except for this.

[Comparative Example 3]
53.00 g of isopropyl alcohol (IPA) was used as an organic solvent. A coating liquid was prepared in the same manner as in Example 1 except for this.

[Comparative Example 4]
As a fluorine-based oligomer having a reactive group, 0.40 g of Viscoat 3F (solid concentration: 100% by mass) manufactured by Osaka Organic Chemical Industry Co., Ltd. was used, and the amount of MIBK was 44.40 g. A coating liquid was prepared in the same manner as in Example 1 except for this.

Claims (5)

A curable oligomer, a fluorine-based oligomer having a reactive group that binds to the curable oligomer , and an organic solvent,
The curable oligomer is at least one of a thermosetting oligomer, an ultraviolet curable oligomer, and an electron beam curable oligomer,
The fluorine-based oligomer has an average molecular weight of 1000 to 10000,
The curable oligomer has an average molecular weight of 1000 to 10000,
The solubility parameter of the organic solvent is 11 [(cal/cm ³ ) ^1/2 ] or less,
The surface tension of the fluorine-based oligomer (ST _A [mN/m]) and the surface tension of the curable oligomer (ST _B [mN/m]) satisfy the following relational expression: coating liquid.
ST _A ≤ 22
28≦ST _B ≦32
ST _B −ST _A ≧7.5 (meth) containing a fluorine-based oligomer having an acryloyl group, a curable oligomer, and an organic solvent,
The curable oligomer is at least one of difunctional to tetrafunctional urethane (meth)acrylate oligomers and epoxy acrylates,
The solubility parameter of the organic solvent is 11 [(cal/cm ³ ) ^1/2 ] is less than or equal to
The surface tension of the fluorine-based oligomer (ST _A. [mN/m]) and the surface tension of the curable oligomer (ST _B. [mN/m]) satisfies the following relational expression.
ST _A. ≦22
28≦ST _B. ≦32
ST _B. -ST _A. ≧7.5 A curable oligomer, a fluorine-based oligomer having a reactive group that binds to the curable oligomer, an organic solvent, a cluster forming agent, and particles obtained by treating the surface of inorganic oxide particles with a surfactant,
The curable oligomer is at least one of a thermosetting oligomer, an ultraviolet curable oligomer, and an electron beam curable oligomer,
The solubility parameter of the organic solvent is 11 [(cal/cm ³ ) ^1/2 ] is less than or equal to
the cluster-forming agent is an acrylic, acrylsilicone, silicone or fluorine-based surface control agent;
The particles have an average particle diameter of 10 to 300 nm,
The surface tension of the fluorine-based oligomer (ST _A. [mN/m]) and the surface tension of the curable oligomer (ST _B. [mN/m]) satisfies the following relational expression.
ST _A. ≦22
28≦ST _B. ≦32
ST _B. -ST _A. ≧7.5 Including second particles obtained by treating the surface of the second inorganic oxide particles with a silane coupling agent having a reactive group that binds to the curable oligomer ,
4. The coating liquid according to claim 3 , wherein the second particles have an average particle size of 10 to 150 nm. A step of applying the coating liquid according to any one of claims 1 to 3 to a substrate;
and a step of drying and then curing the coating liquid to form a film on the substrate.