JP2007119734A - Primer composition, and fluorine resin composite laminate material and fixing belt of electronic photographic image-forming device by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a primer composition capable of directly applying it on the surface of a silicone rubber, etc., having a low surface tension, without forming cissing, capable of forming a uniform primer layer and also obtaining a firm bonding strength with a fluorine resin layer, and a fluorine resin composite laminate material by using the same. <P>SOLUTION: This primer composition is provided by containing thermally meltable fluorine resin powder having ≥5 μm and ≤50 μm mean particle diameter, a diol having <200°C boiling point, a polyethylene glycol and an epoxysilane. The fluorine resin composite laminate material obtained by forming the primer layer by applying the primer composition on the substrate and then drying at ≤150°C temperature, applying the fluorine resin on the outer surface of the primer layer and then baking at a temperature at or higher than the melting point of the fluorine resin is also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a primer composition that can be directly applied to the surface of a substrate that has low surface tension and is difficult to wet, such as silicone rubber, and can bond the fluororesin layer and the substrate with sufficient adhesive strength, and The present invention relates to a fluororesin composite laminate using More specifically, the present invention relates to a composite laminate including a silicone rubber, a primer layer composed of the above composition, and a fluororesin layer formed on the primer layer, and preferably used for a fixing belt of an electrophotographic image forming apparatus. .

  In color image forming apparatuses such as facsimiles, copiers, and laser beam printers that use an electrophotographic method, a fixing device for thermally fixing a color toner image to a copy paper or the like has several types of color toners such as cyan, yellow, Magenta and black color toners must be sufficiently melted and mixed at a temperature of 140 ° C. to 180 ° C. for color development, and the intermediate colors and the shades of each color must be clearly fixed. Therefore, the fixing device uses a fixing belt having a flexible elastic layer such as silicone rubber, and is heated and melted in a state of wrapping the color toner to produce a mixed color.

  As a fixing member of such an image forming apparatus, Patent Document 1 discloses a fixing belt in which an outermost layer, that is, a layer in contact with toner, is formed with an elastic layer made of silicone rubber or fluorine rubber. Further, in Patent Document 2, a fluororesin release layer is provided on the outer surface of a two-layer tubular product in which a tubular outer layer made of conductive silicone rubber or conductive fluororubber is provided on the outer peripheral surface of the tubular inner layer made of conductive polyimide resin. Further, a fixing belt having a three-layer structure is disclosed, and it is also disclosed that such a fixing belt is used as a fixing belt for a color printer or the like.

  In the fixing belt having the three-layer structure, it is necessary to firmly integrate the polyimide, silicone rubber, and fluororesin layers. Therefore, a primer composition is used as an adhesive for adhering the layers. Each of the materials used is a material with poor adhesion, and there is a problem that the durability of a printer or the like is short because a sufficient adhesive force cannot be obtained particularly at the boundary surface between the silicone rubber and the fluororesin.

  Many types of primer compositions have been developed in order to solve such problems. For example, Patent Document 3 proposes a fluoropolymer simple substance containing a unit derived from fluorinated vinyl ethers containing phosphorus, and a composition of the fluoropolymer simple substance and a non-functional fluoropolymer.

  Further, Patent Document 4 proposes a fluoropolymer having a core / shell structure in which the adhesion of the fluoropolymer core is improved by providing the fluoropolymer core with a shell of a fluorine-substituted copolymer containing copolymerized units of functional monomers. Yes.

  For example, Patent Documents 5 to 8 disclose water-based fluororesin coating materials as primer compositions for bonding silicone rubber and fluororesin. Further, Patent Document 9 discloses that a fluororesin having a phosphate group or a mixture of a fluororesin having this phosphate group and a fluororesin having no functional group is used as a primer composition.

  However, even with these conventional technologies, a primer composition that can bond the fluororesin layer and the silicone rubber layer with sufficient adhesive strength has not been developed, and there is a problem of improving durability and extending the life of printers and the like. It was not solved.

  For this reason, as disclosed in Patent Document 10, the present applicant forms a recess by roughening the surface of the silicone rubber by sandblasting or paper polishing, and impregnating the fluororesin particles in the recess. It has been proposed to provide an anchoring effect by embedding, and further to coat a fluororesin thereon and then baked at a temperature equal to or higher than the melting point of the fluororesin to produce a fused and integrated fixing belt. In this fixing belt, the adhesive strength between the silicone rubber layer and the fluororesin layer is sufficient, but the roughening treatment not only has difficulty in managing the surface roughness, but also has side-effects that cause foreign matter. there were.

In addition, since the primer composition disclosed in the above series of patent documents is a water-based paint in the first place, a “repelling phenomenon” occurs on the silicone rubber having a low surface tension, and it is difficult to apply uniformly. It was. This “repellent phenomenon” not only causes a sufficient adhesion strength between the silicone rubber and the fluororesin when the primer layer is formed on the surface of the silicone rubber and the fluororesin layer is further formed thereon. This leads to an increase in surface roughness and thickness variation of the fluororesin layer, which is a fatal problem. In addition, in order to apply a water-soluble primer composition to the silicone rubber surface, conventionally, a method of suppressing the “repelling phenomenon” by repeating brush coating and drying, or a primer composition impregnated in a sponge or the like on the surface of the silicone rubber is used. However, it is difficult to apply any of the methods with a uniform thickness, which causes variations in adhesive strength and the generation of foreign matter, leaving many problems.
JP 05-154963 A JP 10-305500 A Special Table 2002-514181 Japanese Patent No. 28825579 Japanese Patent Laid-Open No. 06-346017 JP-A-10-305537 International Publication No. 2002/046302 Pamphlet International Publication 2003/006565 Pamphlet Japanese Patent Laying-Open No. 2005-212318 JP 2004-255828 A

  The object of the present invention is to overcome the above-mentioned problems of the prior art, and can be applied directly to the surface of a silicone rubber or the like having a low surface tension by a method such as dipping. An object of the present invention is to provide a primer composition capable of forming a primer layer and capable of firmly bonding a silicone rubber and a fluororesin layer.

  The primer composition of the present invention contains a heat-meltable fluororesin powder having an average particle size of 5 μm or more and 50 μm or less, a diol having a boiling point of less than 200 ° C. at normal pressure, polyethylene glycol, and epoxysilane. Here, “normal pressure” is 1013 hPa.

  In this primer composition, the heat-meltable fluororesin powder includes tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and tetrafluoroethylene. Hexafluoropropylene / perfluoro (alkyl vinyl ether) copolymer (EPE), tetrafluoroethylene / ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE) and chlorotrifluoro It is preferably at least one selected from the group consisting of ethylene / ethylene copolymers (ECTFE).

  Moreover, in this primer composition, it is preferable that the density | concentration of a heat-meltable fluororesin powder is 5 to 50 weight% with respect to the total weight of diol and polyethyleneglycol.

  In this primer composition, the diol is preferably ethylene glycol, propylene glycol, or a mixture of ethylene glycol and propylene glycol.

  In the primer composition, the number average molecular weight of polyethylene glycol is preferably 200 or more and less than 1,000.

  In this primer composition, the epoxy silane is 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, (3-glycidoxypropyl) Trimethoxysilane, (3-glycidoxypropyl) triethoxysilane, 5,6-epoxyhexyltriethoxysilane, (3-glycidoxypropyl) methyldiethoxysilane, (3-glycidoxypropyl) methyldimethoxysilane And at least one selected from the group consisting of (3-glycidoxypropyl) dimethyldiethoxysilane.

  In the primer composition, the concentration of the epoxy silane is preferably 1% by weight or more and 10% by weight or less based on the total weight of the diol and the polyethylene glycol.

  The fluororesin composite laminate of the present invention includes a primer layer formed by forming the primer composition on a substrate and a fluororesin layer formed on the primer layer.

  The fixing belt of the electrophotographic image forming apparatus of the present invention includes a primer layer formed by forming the primer composition on a substrate and a fluororesin layer formed on the primer layer.

  ADVANTAGE OF THE INVENTION According to this invention, the primer composition which can adhere | attach a silicone rubber layer and a fluororesin layer firmly can be provided. The primer composition of the present invention can be applied by a method such as dipping directly on a substrate having a small surface tension, a large contact angle, and difficult to wet, such as silicone rubber, without subjecting it to a roughening treatment. A coating can be obtained. In addition, according to the present invention, the primer layer obtained by applying the primer composition to the substrate and drying is formed of fine-particle heat-meltable fluororesin powder, and therefore the surface roughness preferable for the heat-meltable fluororesin. Degree. For this reason, a fluororesin liquid can be uniformly apply | coated on a primer layer. As a result, the silicone rubber and the fluororesin can be firmly bonded. The surface roughness of the primer layer also affects the surface roughness of the fluororesin layer applied thereon, but in the primer composition of the present invention, a heat-meltable fluororesin powder having a desired particle size is used. By using it, a fixing belt having a surface roughness suitable as a fixing belt of an electrophotographic image forming apparatus can be provided.

  The present invention relates to a primer composition and a fluororesin composite laminate comprising a primer layer formed by forming the primer composition on a substrate and a fluororesin layer formed on the primer layer. The fluororesin composite laminate is, for example, a fixing belt suitably used in the electrophotographic image forming apparatus shown in FIGS. FIG. 1 is a schematic view of a fixing device using a fluororesin composite laminate (fixing belt) of the present invention. In the figure, the fluororesin composite laminate heat fixes a toner image 8 formed on the surface of a copy paper 7. It is used as a fixing belt 1 for this purpose. A belt guide 2 and a ceramic heater 3 are provided inside the fixing belt 1. In this fixing device, the copy paper on which the toner image is formed is sequentially fed between the ceramic roller 3 and the pressure roll 4 in pressure contact, and the toner is heated and melted and thermally fixed on the copy paper. In FIG. 1, reference numeral 5 denotes a thermistor, reference numeral 9 denotes a fixed toner, reference numeral 6 denotes a cored bar portion of the pressure roller, and reference numeral N denotes a nip surface between the fixing belt and the pressure roller 4. is there.

  FIG. 2 is a schematic sectional view of the fixing belt. FIG. 2 shows a fixing belt having a three-layer structure. In the three-layer fixing belt, the base material 11 is a thin-layer tubular material such as polyimide or metal. Further, a silicone rubber layer or the like is used as the elastic layer 12. A fluororesin release layer 13 is formed on the outer surface of the elastic layer 12. The primer composition of the present invention is applied as a primer layer 14 applied to the interface between the polyimide tubular material and the silicone rubber and the interface between the silicone rubber and the fluororesin, and firmly bonds and integrates the three layers described above. ing.

  The primer composition of the present invention contains hot-melt fluororesin powder, diol, polyethylene glycol, and epoxy silane.

  In the primer composition of the present invention, the average particle size of the heat-meltable fluororesin powder needs to be 5 μm or more and 50 μm or less. If it is less than 5 μm, the surface roughness of the primer layer formed after applying the primer composition to the substrate and drying is too low to repel water, so apply a fluororesin aqueous coating on the primer layer in the next step. It is because it is not possible. On the other hand, if the thickness exceeds 50 μm, not only dispersion of the primer composition is likely to occur, but also dispersion stability is not obtained, and the surface roughness of the primer layer formed after drying becomes too high. This is because the formation of a proper fluororesin layer is hindered.

  In the present invention, as the heat-meltable fluororesin powder, tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / hexafluoropropylene Perfluoro (alkyl vinyl ether) copolymer (EPE), tetrafluoroethylene / ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and chlorotrifluoroethylene / ethylene At least one selected from the group consisting of a copolymer (ECTFE) can be used. You may use these mixtures as needed.

  In the present invention, the concentration of the heat-meltable fluororesin powder is preferably 5% by weight or more and 50% by weight or less with respect to the total weight of the diol and polyethylene glycol. If the amount is less than 5% by weight, the required amount of the heat-meltable fluororesin powder is insufficient, and the surface roughness of the primer layer formed after drying is too low to repel water. It is not possible. Further, if it exceeds 50% by weight, the heat-meltable fluororesin powder tends to precipitate in the primer composition. More preferably, the concentration is 10% by weight or more and 30% by weight or less.

  In the present invention, the diol used as a solvent needs to have a boiling point at atmospheric pressure of less than 200 ° C. This is because when the boiling point is 200 ° C. or higher, the non-volatility becomes high, and the drying temperature for forming the primer layer becomes high. A boiling point of less than 200 ° C. is preferable because the primer layer can be formed under conditions of 150 ° C. and about 20 minutes. In the present invention, it is preferable to use ethylene glycol or propylene glycol as the diol having a boiling point of less than 200 ° C.

  In the present invention, it is necessary to use polyethylene glycol as the binder resin of the fluororesin powder. This is because if polyethylene glycol is not used, the fluororesin powder falls off from the primer layer after drying. The number average molecular weight of polyethylene glycol is preferably 200 or more and less than 1,000. This is because if the number average molecular weight is less than 200, the surface roughness of the primer layer formed after drying becomes too high, which hinders the formation of a smooth fluororesin layer. In addition, when the number average molecular weight is 1,000 or more, it is grease-like or wax-like at room temperature, and the solubility in diol having a boiling point of less than 200 ° C. is remarkably low. This is because the fluororesin layer is volatilized and decomposed during high-temperature firing in forming the fluororesin layer with a water-based paint, causing cracks and pinhole defects in the fluororesin layer.

  In the present invention, as the epoxy silane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, (3-glycidoxypropyl) trimethoxysilane, (3-glycidoxypropyl) triethoxysilane, 5,6-epoxyhexyltriethoxysilane, (3-glycidoxypropyl) methyldiethoxysilane, (3-glycidoxypropyl) methyldimethoxysilane, and (3 -Glycidoxypropyl) At least one selected from the group consisting of dimethyldiethoxysilane can be used. Among these, (3-glycidoxypropyl) trimethoxysilane is most preferable from the viewpoint of price.

  In the present invention, the concentration of the epoxy silane is preferably 1% by weight or more and 10% by weight or less based on the total weight of the diol and polyethylene glycol dispersion. This is because if it is less than 1% by weight, sufficient adhesive strength is not exhibited, and if it exceeds 10% by weight, it is not preferable in terms of price.

  In addition, when manufacturing the primer composition of this invention, even if the following well-known fillers are added, it does not interfere at all. For example, mica, talc, kaolin, bentonite, montmorillonite, carbon black, magnesium oxide, aluminum oxide, silicon oxide, titanium oxide, zinc oxide, tin oxide, aluminum borate, boron nitride, aluminum nitride, silicon nitride, potassium titanate And powders or fibers such as barium titanate, fullerenes, carbon nanotubes and the like.

  Moreover, when manufacturing the primer composition of this invention, even if the following well-known solvent is added for viscosity adjustment etc., it does not interfere. For example, alcohols such as methanol, ethanol, isopropanol, butanol, diacetone alcohol, butylene glycol, 2-butene-1,4-diol, pentamethylene glycol, 2-methyl-2,4-pentanediol, 2-ethyl- Diols such as 1,3-hexanediol, diethylene glycol, triethylene glycol, and tetraethylene glycol; triols such as glycerin, 2-ethyl-2-hydroxymethyl-1,3-propanediol, and 1,2,6-hexanetriol , Ethylene glycol methyl ether, ethylene glycol butyl ether, ethylene glycol dimethyl ether, diethylene glycol methyl ether, diethylene glycol butyl ether, diethylene glycol dimethyl Glycol ethers such as ether, triethylene glycol methyl ether, triethylene glycol dimethyl ether, polypropylene glycol, polytetramethylene glycol, polyoxyethylene polyoxypropylene glycol, dimethicone copolyol and poly (oxyethylene oxypropylene) methyl polysiloxane Polymers, other cyclic ethers such as tetrahydrofuran and dioxane, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, ethyl acetate, butyl acetate, diethyl carbonate, and γ-butyrolactone Esters such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, etc. Amides and the like. Among these, in order to prevent dripping after application of the primer composition, it is preferable to add a volatile solvent. Furthermore, it is preferable to add alcohols such as methanol, ethanol, isopropanol, butanol, and diacetone alcohol in order to prevent the epoxysilane from being deactivated by the reaction in the primer composition.

  Moreover, when manufacturing the primer composition of this invention, even if it uses the following well-known additives, it does not interfere at all. For example, fillers, pigments, pigment dispersants, solid lubricants, anti-settling agents, leveling agents, surface modifiers, thixotropic agents, moisture absorbers, anti-gelling agents, antioxidants, UV absorbers, light stability Agents, plasticizers, anti-coloring agents, anti-skinning agents, surfactants, antistatic agents, antifoaming agents, antibacterial agents, antifungal agents, antiseptics, thickeners and the like.

  In the present invention, the substrate for forming the primer layer is not particularly limited, and as a substrate for forming the primer layer, metals such as iron, stainless steel, aluminum, brass, glass, glass plate, glass fiber, etc. Heat resistant resins such as glass, polyurethane, nylon, polysulfone, polyethersulfone, polyetheretherketone, polyamideimide, polyimide, silicone rubber, fluororubber, silicone EPDM (ethylene propylene) rubber, silicone acrylic, silicone polyethylene, etc. Rubbers such as hybrid rubber of silicone rubber and other organic polymers can be used. In color image forming apparatuses such as facsimiles, copiers, and laser beam printers that use electrophotography, it is preferable to select silicone rubber, polyimide, stainless steel, nickel, or aluminum as the base material on which the primer layer is formed.

  In this invention, when apply | coating a primer composition to a base material, it is preferable to fully degrease and wash | clean. In particular, when applying the primer composition to the surface of the silicone rubber, it is preferable to modify the surface of the silicone rubber in advance in order to improve adhesion. For example, (a) Corona discharge treatment in which high voltage is applied between electrodes in the atmosphere to cause dielectric breakdown, (b) Irradiation treatment with a short wavelength ultraviolet ray from a mercury lamp, (c) Flame treatment to be passed through a strong oxidation flame, ( d) Plasma treatment by glow discharge in a low-pressure inert gas, oxygen, halogen gas, or the like, and (e) treatment of applying a coupling agent such as silane, titanium or aluminum on the surface. . Of these, the corona discharge treatment is particularly preferable because the adhesive strength can be increased by a simple treatment. Further, these surface modification treatments are not limited to one type, and a plurality thereof may be combined.

  In the present invention, a known method such as a brush coating method, a spin method, a spray method, a dispenser method, or a dip method can be used as a method for applying the primer composition to the surface of a substrate such as silicone rubber.

  In this invention, it is preferable that the drying temperature at the time of forming a primer layer is less than melting | fusing point of a heat-meltable fluororesin powder. More preferably, it is less than 150 ° C. Above the melting point, the heat-meltable fluororesin powder is melted and the surface roughness of the primer layer is lowered, which is not preferable. Specifically, the 10-point average roughness Rz of the primer layer formed after drying is preferably 0.2 μm to 20 μm, and the arithmetic average roughness Ra is preferably 0.1 μm to 5 μm. This is because when Rz is less than 0.2 μm or Ra is less than 0.1 μm, water is repelled, so that a fluororesin aqueous paint cannot be applied. When Rz exceeds 20 μm or Ra exceeds 5 μm, a fluororesin aqueous paint can be applied, but the surface roughness of the fluororesin layer formed after firing becomes high.

  In the present invention, the primer layer formed by drying has an appropriate surface roughness. For this reason, the fluororesin water-based paint can be applied by a known method such as a spin method, a spray method, or a dip method.

  Hereinafter, the present invention will be described in detail by way of examples and comparative examples. “Viscosity” was measured using a viscometer LVT (manufactured by Brookfield), and “surface roughness” was measured using a surface roughness measuring device SE-3H (manufactured by Kosaka Laboratory). Here, the “surface roughness” is a ten-point average roughness Rz and an arithmetic average roughness Ra based on JIS-B0601. Further, the “adhesion strength” between the silicone rubber layer 12 and the fluororesin layer 13 in the fixing belt was measured using a measuring machine shown in FIG.

  FIG. 3 shows an outline of the “adhesion strength” measuring device 50. In the measuring machine 50, ball bearings are inserted into both end portions inside the sample mounting jig 17. That is, the measuring machine 50 has a mechanism that allows the sample mounting jig 17 to freely rotate around the mandrel 19 attached to the support base 18. Note that the frictional force of the sample mounting jig 17 is a minute one that does not cause a problem in this measurement.

  The “adhesive strength” measurement sample 20 is prepared by cutting the fixing belt so that the length in the longitudinal direction is 40 to 50 mm. That is, the measurement sample 20 has a cylindrical shape. Then, after the measurement sample 20 is inserted into the sample mounting jig 17, both ends are fixed to the sample mounting jig 17 with the adhesive tape 21.

  The adhesive tape 22 having a width of 15 mm is attached to the central portion in the length direction of the measurement sample 20 mounted on the mounting jig for one turn along the circumferential direction so that the end portion of the adhesive tape can be grasped by the chuck of the tensile tester. Cut the adhesive tape longer. Thereafter, a first cut (hereinafter referred to as a circumferential cut) 23 is made with a knife at a width of 10 mm from the top of the adhesive tape at the center of the measurement sample 20 to which the adhesive tape has been attached. At this time, a knife is inserted so that the circumferential cut 23 is formed only in the adhesive tape and the outermost fluororesin layer.

  Then, a cut perpendicular to the weekly cut 23 (hereinafter referred to as a vertical cut) is made in a portion close to the starting point of the adhesive tape to the roller, and this vertical cut is used as the peeling start point, and the end of the adhesive tape. The fluororesin layer is peeled off a little in advance and is attached to the adhesive tape. At this time, as in the case of making the circumferential cut, a knife is put so that the cut is made only in the adhesive tape and the outermost fluororesin layer. Next, the long cut adhesive tape is gripped by the chuck 24 of the tensile tester, pulled at a speed of 50 mm / min, and the “adhesive strength” is continuously recorded on the chart. “Adhesive strength” with the fluororesin layer. Here, the adhesive tape is supplementarily attached to the surface of the fluororesin layer of the measurement sample and peeled off together with the adhesive tape by a tensile tester. When the peel test is performed with a width of 10 mm, the thickness of the fluororesin layer is 20 This is because the film thickness is ˜30 μm, and the film is stretched, and an accurate “adhesive strength” cannot be measured.

A primer layer and a fluororesin composite laminate were evaluated by preparing a fixing belt having a three-layer structure in which the base material was polyimide, the elastic layer was silicone rubber, and the release layer was fluororesin.
(1) “Preparation of polyimide tube”
An aluminum mold having an outer diameter of 30 mm and a length of 500 mm and having a silicon oxide coating agent baked on the surface was prepared. Next, a 1,000 poise polyimide precursor solution (trade name “RC5063 PyreML varnish” manufactured by IST Co., Ltd.) was formed on the surface of the mold with a thickness of 800 μm, dried, and then heated stepwise to 400 ° C. for imidization. Was completed to produce a polyimide tubular product having an inner diameter of 30 mm and a thickness of 50 μm.
(2) “Preparation of primer composition”
KLUCEL G as a thickener in a mixed solvent of 100 g of ethanol, 700 g of ethylene glycol (made by Daiichi Kogyo Seiyaku) as a diol having a boiling point of less than 200 ° C., and 300 g of polyethylene glycol (Daiichi Kogyo Seiyaku) with a number average molecular weight of 200 ( 3 g) and 150 g of heat-meltable fluororesin powder “FEP532-8000” (Mitsui / DuPont Fluorochemical) were added and stirred well. Next, 50 g of (3-glycidoxypropyl) trimethoxysilane “TSL8350” (GE, manufactured by Toshiba Silicone) was added as an epoxy silane to prepare a primer composition having a viscosity of 35 cP (23 ° C.).
(3) "Shaping and vulcanization of silicone rubber elastic body"
A silicone rubber primer composition (GE / Toshiba silicone: trade name: XP-81-405) was applied to a polyimide tubular product molded into a mold by a dipping method so as to have a thickness of 3 μm after drying, at 150 ° C. The primer layer was formed by drying for 20 minutes. Thereafter, a silicone rubber “XE-15-7354” (manufactured by GE / Toshiba Silicone) was formed on the outer surface of the primer layer by a die dropping method so that the thickness was uniformly 180 μm, and then at 150 ° C. for 30 minutes, 200 ° C. And vulcanized by heating for 4 hours to produce a tubular product in which an elastic layer made of silicone rubber was formed on the outer surface of the tubular product made of a polyimide base material.
(4) “Application and drying of primer composition”
The surface of the tubular silicone rubber layer made of polyimide / silicone rubber prepared in the item (3) was subjected to corona discharge treatment at 1 kV for 60 seconds. Next, the primer composition prepared in the above item (2) was applied using a dipping method so as to have a thickness of 3 μm after drying, and dried at 150 ° C. for 20 minutes to form a primer layer. The ten-point average roughness Rz and arithmetic average roughness Ra of the primer layer were 12 μm and 1.2 μm, respectively.
(5) "Application and baking of fluororesin aqueous paint"
Using a dipping method, a fluororesin aqueous paint “EN-400CL” (Mitsui / DuPont Fluorochemical) was applied to the surface of the tubular product in the above item (4) to a thickness of 30 μm and then fired at 350 ° C. for 30 minutes. By forming a fluororesin layer, a three-layer fluororesin composite laminate (fixing belt) in which a silicone rubber layer is formed on the outer surface of the polyimide base material and a fluororesin layer is further formed on the outer surface of the silicone rubber layer is formed. Produced.

  As a result of measuring the adhesive strength between the fluororesin layer and the silicone rubber layer in the fluororesin composite laminate according to the above measurement method, the fluororesin layer and the silicone rubber layer are strong enough to cause the cohesive failure of the silicone rubber layer during the measurement. The adhesive strength was 235 gf / cm.

  A fluororesin composite laminate (fixing belt) was prepared and evaluated in the same manner as in Example 1 except that the addition amount of the heat-meltable fluororesin powder in Example 1 was changed from 150 g to 100 g. The results are shown in Table 1.

  A fluororesin composite laminate (fixing belt) was prepared and evaluated in the same manner as in Example 1 except that propylene glycol was used instead of ethylene glycol in Example 1. The results are shown in Table 1.

  A fluororesin composite laminate (fixing) was carried out in the same manner as in Example 1 except that (3-glycidoxypropyl) methyldimethoxysilane “TSL8355” (GE, manufactured by Toshiba Silicone) was used instead of epoxysilane in Example 1. Belt) was prepared and evaluated. The results are shown in Table 1.

  A fluororesin composite laminate (fixing belt) was prepared in the same manner as in Example 1 except that 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (manufactured by Gelest) was used instead of epoxysilane in Example 1. Prepared and evaluated. The results are shown in Table 1.

(Comparative Example 1)
A fluororesin composite laminate (fixing belt) was prepared and evaluated in the same manner as in Example 1 except that the addition amount of the heat-meltable fluororesin powder in Example 1 was changed from 150 g to 50 g. However, the interface between the fluororesin layer and the silicone rubber layer was easily peeled off. The adhesive strength was as low as 25 gf / cm.
(Comparative Example 2)
A fluororesin composite laminate (fixing belt) was prepared and evaluated in the same manner as in Example 1 except that the amount of epoxysilane added in Example 1 was changed from 50 g to 5 g. However, some floating was observed without bonding.
(Comparative Example 3)
A primer layer was formed in the same manner as in Example 1 except that the addition amount of ethylene glycol was changed from 700 g to 1,000 g and the addition amount of polyethylene glycol was changed from 300 g to 0 g in Example 1. However, since the fluororesin powder of the primer layer is not bound, the fluororesin powder easily dropped off from the primer layer.
(Comparative Example 4)
A fluororesin composite laminate (fixing belt) was prepared in the same manner as in Example 4 except that the amount of epoxysilane (3-glycidoxypropyl) methyldimethoxysilane added in Example 4 was changed from 50 g to 5 g. It produced and evaluated. However, some floating was observed without bonding.
(Comparative Example 5)
A fluororesin composite laminate (fixing belt) was prepared in the same manner as in Example 5 except that the amount of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane added as epoxy silane in Example 5 was changed from 50 g to 5 g. ) And evaluated. However, some floating was observed without bonding.
(Comparative Example 6)
A primer layer was formed in the same manner as in Example 1 except that the amount of the heat-meltable fluororesin powder added in Example 1 was changed from 150 g to 5 g. However, the surface roughness of the primer layer was too low to repel water, and the fluororesin aqueous paint could not be applied.
(Comparative Example 7)
In the same manner as in Example 1 except that polyethylene glycol having a number average molecular weight of 1,000 was used instead of polyethylene glycol having a number average molecular weight of 200 in Example 1, a fluororesin composite laminate was obtained. A body (fixing belt) was prepared. However, there were numerous pinhole defects in the coating.

  The primer composition of the present invention can be directly applied and firmly adhered even to a material that has a low surface tension and is difficult to wet, such as silicone rubber. Further, the fluororesin composite laminate of the present invention can be suitably used as a fixing belt of an electrophotographic image forming apparatus, and the durability of a printer or a copying machine can be greatly extended.

It is the schematic which shows the fixing device using the fluororesin composite laminated body which concerns on this invention. 1 is a schematic cross-sectional view of a fixing belt according to the present invention. It is a perspective view which shows the measurement test of the adhesive strength of the primer composition which concerns on this invention.

Explanation of symbols

1,10 Fluororesin composite laminate (fixing belt)
11 Silicone rubber layer 13 Fluororesin layer 14 Primer layer 17 Sample mounting jig 18 Support base 19 Mandrel 20 Measurement sample 21 Adhesive tape 22 Adhesive tape 23 Break 24 Tension tester chuck 50 Adhesive strength tester

Claims (9)

A heat-meltable fluororesin powder having an average particle diameter of 5 μm or more and 50 μm or less;
A diol having a boiling point of less than 200 ° C. at normal pressure;
Polyethylene glycol,
A primer composition containing epoxy silane. The heat-meltable fluororesin powder includes tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / hexafluoropropylene / perfluoro. (Alkyl vinyl ether) copolymer (EPE), tetrafluoroethylene / ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and chlorotrifluoroethylene / ethylene copolymer The primer composition according to claim 1, which is at least one selected from the group consisting of (ECTFE). The primer composition according to claim 1 or 2, wherein the concentration of the heat-meltable fluororesin powder is 5% by weight or more and 50% by weight or less based on the total weight of the diol and polyethylene glycol. The primer composition according to any one of claims 1 to 3, wherein the diol is ethylene glycol, propylene glycol, or a mixture of the ethylene glycol and the propylene glycol. The polyethylene glycol has a number average molecular weight of 200 or more and less than 1,000.
The primer composition according to any one of claims 1 to 4. The epoxy silane is 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, (3-glycidoxypropyl) trimethoxysilane, (3- Glycidoxypropyl) triethoxysilane, 5,6-epoxyhexyltriethoxysilane, (3-glycidoxypropyl) methyldiethoxysilane, (3-glycidoxypropyl) methyldimethoxysilane, and (3-glycid At least one selected from the group consisting of (xypropyl) dimethyldiethoxysilane,
The primer composition according to any one of claims 1 to 5. The concentration of the epoxy silane is 1% by weight or more and 10% by weight or less based on the total weight of the diol and polyethylene glycol.
The primer composition according to any one of claims 1 to 6. A primer layer formed by forming the primer composition according to any one of claims 1 to 7 on a substrate;
A fluororesin composite laminate comprising a fluororesin layer formed on the primer layer. A primer layer formed by forming the primer composition according to any one of claims 1 to 7 on a substrate;
A fixing belt of an electrophotographic image forming apparatus comprising a fluororesin layer formed on the primer layer.

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