JP2011013629A - Sliding member and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sliding member which is well balanced between sliding resistance and strength.SOLUTION: The sliding member includes a porous fluororesin film, wherein a thermosetting resin and a lubricant are kept in the pores in the porous fluororesin film. The porous fluororesin film can be embossed.

Description

  The present invention relates to a sliding member used for a sliding portion of a machine part. More specifically, a sheet-like sliding member (sometimes referred to as “sliding sheet”) disposed on the sliding surface of an image fixing device (electrophotographic image forming apparatus) such as a copying machine, a printer, or a facsimile machine. And a manufacturing method thereof.

  In recent years, there has been a demand for energy saving of electric devices due to various circumstances such as global environment conservation and energy resource depletion. For example, in a thermal fixing device of an image forming apparatus such as a printer, a copying machine, and a facsimile, a thermal fixing method using an endless belt is adopted for the purpose of speeding up, shortening a startup time, miniaturization, and energy saving.

  For example, in a copying machine, a photoconductor formed in a drum shape is uniformly charged, and the photoconductor is exposed to light controlled based on image information to form an electrostatic latent image (toner) on the photoconductor. Then, the toner is transferred onto a recording medium such as paper in an unfixed state by an image fixing device, and fixed on the recording medium by heating / pressing.

  For example, Patent Documents 1 and 2 describe an image fixing device that includes a pressure roll that is rotatably disposed and a cylindrical endless belt that is rotatably pressed against the pressure roll. Yes. A pressure member (pressing pad) that presses the endless belt toward the pressure roll side is provided inside the endless belt, and a sliding member containing a lubricant is provided between the pressure member and the endless belt. Is provided. The sliding member plays a role of causing the endless belt to follow the belt without being delayed by the peripheral speed of the fixing roll.

  Usually, a liquid lubricant such as silicone oil is interposed between the sliding member and the endless belt for the purpose of further smoothing the sliding of the sliding member and reducing the wear of the sliding member. .

  This sliding member was prepared by impregnating and coating a glass cloth woven with glass fibers impregnated with tetrafluoroethylene resin (polytetrafluoroethylene: PTFE) as described in Patent Document 2. Glass Teflon (Teflon is a registered trademark of DuPont, USA) is heavily used. Glass Teflon exhibits excellent slidability due to the low friction property of the tetrafluoroethylene resin itself and the small contact area with the sliding counterpart member. This is due to the surface protrusions resulting from the woven structure of the sliding member.

  However, when glass Teflon is used for a long time in the heat and pressure environment of a heat fixing device of an image fixing device (electrophotographic image forming device), the surface irregularity of the surface of the tetrafluoroethylene resin layer of the surface layer is reduced due to the creep phenomenon. In addition, there is a problem that the glass cloth is exposed due to wear of the tetrafluoroethylene resin layer. When the glass cloth is exposed, the endless belt is damaged, and the fixed image becomes rough. Further, when the sliding resistance increases, it becomes a burden on the bearings, gears, and motors used in the heat fixing type image fixing device, which causes an increase in energy loss and a failure of the device.

  In order to solve the problem of glass Teflon, various techniques that do not use glass cloth are known. For example, Patent Document 3 describes a sliding sheet made of a fluororesin layer that employs a special uneven structure on the sliding surface. However, when this sliding sheet is used for a long time in the heat and pressure environment of the image forming apparatus, the special uneven structure is crushed and the sliding surface becomes smooth due to the creep phenomenon and wear of the fluororesin that forms the sliding surface. Sliding resistance increases.

  In addition, Patent Document 4 and Patent Document 5 describe a technique in which a thermosetting polyimide film having unevenness formed by embossing on the surface of a resin film is used as a sliding member. Since the process of handling the polyimide precursor is complicated, there is a limit to improving the production efficiency.

  On the other hand, Patent Document 6 describes a sliding material in which a porous body of PTFE is impregnated with a polyimide resin. In Patent Document 6, a porous body of PTFE is completely impregnated with a polyimide resin (the upper left column on page 3). Therefore, lubricating oil having a lubricating action is not included in the porous body, and sliding The sliding resistance of the member is considered high.

  Patent Document 7 describes a composite porous sliding material made of PTFE, a heat-resistant resin, and a solid lubricant as a material having low sliding resistance. The porous sliding material is formed by mixing a solid lubricant, but the porous portion of the porous sliding material is not impregnated with lubricating oil. Therefore, the sliding resistance is not sufficiently reduced. Moreover, since PTFE is not a stretched continuous body, it lacks flexibility and strength.

  Patent Document 8 describes a sliding material in which a deformation preventing film is laminated and bonded to a non-sliding surface of a porous tissue material made of a fluororesin. However, such a sliding material is susceptible to creep and wear on the sliding surface, and it is difficult to start at a low temperature because it is too familiar with the lubricating oil interposed between the sliding member.

JP 2001-228731 A JP-A-10-213984 JP 2005-91557 A JP-A-2005-3969 JP 2005-246793 A JP-A-61-2228122 Japanese Patent Laid-Open No. 2-118216 JP 2003-191389 A

  However, the glass cloth Teflon material described in the above-mentioned patent document 3 has a contact area with the endless belt that becomes a sliding counterpart member because the fluororesin on the surface creeps or wears out after a long period of use. , Sliding resistance increases. If the surface resin is worn too much, the internal glass cloth is exposed and the endless belt is damaged, resulting in fatal damage to the image fixing device.

In addition, in order to operate for a long time while keeping the sliding resistance low, it is necessary to supply lubricating oil to the interface between the sliding member and the sliding counterpart member (that is, the surface of the sliding member). Installation of parts such as oil-impregnated felt and oil-impregnated roll is necessary, which hinders downsizing of the image fixing device.

  This invention is made | formed in view of the above situations, and it aims at providing the sliding member which can hold down sliding resistance low over a long period of time.

  The sliding member of the present invention capable of achieving the above object is a sliding member including a porous fluororesin film, and a thermosetting resin and a lubricant are held in the pores of the porous fluororesin film. It is.

  In the sliding member, it is desirable that the porous fluororesin film is embossed, and the number density of convex portions formed on the porous fluororesin film by embossing is 200 pieces / square. It is more desirable that it be an inch or more.

  In the sliding member, it is preferable that the porous fluororesin film is a polytetrafluoroethylene film.

  In the sliding member, it is preferable that the porosity of the porous fluororesin film is 40 to 95%. The lubricant is preferably oil.

  The manufacturing method of the sliding member of the present invention that can achieve the above object includes a step of producing a porous fluororesin film, a step of impregnating a part of the pores of the porous fluororesin film with a thermosetting resin, A step of curing the thermosetting resin, and a step of impregnating the porous fluororesin film with a lubricant.

  In the manufacturing method of the sliding member, the step of curing the thermosetting resin is a step of semi-curing the thermosetting resin, and then embossing the porous fluororesin film, It is desirable to further include a step of further curing the thermosetting resin.

  The sliding member of the present invention comprises a main body of the sliding member made of a porous fluororesin film, and holds both the thermosetting resin and the lubricant in the pores of the porous fluororesin film. By holding the resin, it is possible to increase the strength of the sliding member while maintaining the low slidability and flexibility of the sliding member, and to further suppress the sliding resistance by holding the lubricant. Therefore, it is possible to provide an image fixing device with high image quality.

  Hereinafter, a sliding member and a manufacturing method thereof according to an embodiment of the present invention will be described. The sliding member according to the embodiment of the present invention has a porous fluororesin film as a basic component. The hole of the porous fluororesin film (1) holds the thermosetting resin (2) and the lubricant (3), and these will be described below in order.

1. Sliding member (1) Porous fluororesin film Since fluororesin is excellent in releasability, slidability, and flexibility, it is used as a basic structure of the sliding member. Since the porous fluororesin film in the present invention does not contain a hard material such as glass cloth, even if the surface is worn, the hard member is not exposed as in the case of using glass cloth Teflon, and the sliding partner The member is not damaged.

  A preferred porous fluororesin membrane is a porous polytetrafluoroethylene membrane (porous PTFE membrane). A porous PTFE membrane is formed by mixing a PTFE fine powder with a molding aid, forming a paste, removing the molding aid from the molded body, stretching at a high temperature and high speed, and further firing if necessary. Can be obtained. As the paste molded body to be used for stretching, either a semi-green body or a fired body can be used.

  Stretching is performed below the melting point of the porous fluororesin. The stretching may be uniaxial stretching or biaxial stretching. For example, a uniaxially stretched porous PTFE film has thin island-like nodes (folded crystals) that are substantially perpendicular to the stretching direction in a microscopic manner, and interdigital fibrils (the folded crystals are stretched). Is characterized in that the linear molecular bundles melted and drawn out by (1) are oriented in the stretching direction. On the other hand, the biaxially stretched porous PTFE film has a cobweb-like fibrous structure in which fibrils spread radially, nodes connecting the fibrils are scattered in islands, and there are many spaces divided by the fibrils and nodes. There is a micro feature in the point. The biaxially stretched porous PTFE film is particularly suitable because it is easier to widen than the uniaxially stretched porous PTFE film, has an excellent balance of physical properties in the vertical and horizontal directions, and lowers the production cost per unit area. Used.

  It is recommended that the porosity of the porous fluororesin film is, for example, about 40% or more (preferably 50% or more) and 95% or less (preferably 85% or less). The porosity of the porous PTFE membrane can be adjusted as appropriate depending on the draw ratio. If the porosity is less than 40%, it is difficult to make the impregnated resin uniform with a small pore diameter, and the entire porous fluororesin film becomes rich in the fluororesin film, which increases the creep phenomenon. None (more pronounced when the fluororesin is PTFE). On the other hand, when the porosity exceeds 95%, the thermosetting resin becomes rich, and the sliding member becomes inferior in flexibility.

The porosity of the porous fluororesin film is the apparent density D ₂ (D ₂ = W / V: unit) determined by measuring the mass W of the porous fluororesin film and the apparent volume V including the pores. the g / cm ^3), if the true density D (PTFE resin when not being formed at all the holes using a 2.2 g / cm ^3), can be calculated based on the following equation (1). In addition, the thickness at the time of calculating the volume V is based on an average thickness measured with a dial thickness gauge (measured in a state where a load other than the main body spring load is applied using “SM-1201” manufactured by Teclock Co.).
Porosity (%) = [(2.2−D ₂ ) /2.2)] × 100 (1)

  Although the thickness of a porous fluororesin film | membrane is not specifically limited, For example, it is 250 micrometers or less, Preferably it is 200 micrometers or less, More preferably, it is 150 micrometers or less. If the thickness is too thick, the heat capacity of the porous fluororesin film increases, so that an extra amount of heat is required, and printing tends to become unclear due to dispersion of the printing pressure. On the other hand, if it becomes too thin, it may not be able to withstand mechanical stress during actual use and may break, and a continuous layer of thermosetting resin on the surface of the porous fluororesin film when impregnated with thermosetting resin Since PTFE is not exposed on the sliding surface (the surface of the porous fluororesin film), the sliding characteristics are reduced (sliding resistance is increased). Further, since the porous fluororesin film becomes too thin, it becomes difficult to keep the lubricating oil in the pores. Therefore, the thickness of the porous fluororesin film is, for example, 10 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and further preferably 40 μm or more.

(2) Thermosetting resin The thermosetting resin in this Embodiment has the effect | action which raises the intensity | strength and rigidity of a sliding member by being hold | maintained in the void | hole of a porous fluororesin film | membrane. Although the thermosetting resin is formed continuously in a porous PTFE matrix to some extent, it has a structure partitioned by fine PTFE partition walls, which increases the strength and rigidity of the sliding member. However, flexibility is maintained.

  Since the thermosetting resin has a high mechanical strength as described above, the porous fluororesin film can be made thinner accordingly, and the heat capacity of the sliding member can be reduced. This contributes to energy saving of the image fixing device, and the printing pressure is high because the sliding member is thin and flexible, so that the printing pressure is not dispersed.

  The thermosetting resin impregnated in the porous fluororesin film has a function of suppressing the creep phenomenon of the porous fluororesin (PTFE), so that the sliding surface of the sliding member becomes smooth and the sliding counterpart member It is possible to prevent the contact area from increasing. The porous fluororesin film is worn away little by little, and the wear piece covers the surface of the sliding member, and this acts as a transfer film to reduce the sliding resistance.

  The glass transition temperature after curing of the thermosetting resin is desirably 150 ° C. or higher (preferably 200 ° C. or higher). Since the operating temperature of the image fixing device by thermal transfer is very high, if the glass transition temperature in the cured state is less than 150 ° C., a creep phenomenon occurs under thermal pressure and sliding resistance increases. Because. In addition, when embossing is performed on the porous fluororesin film as described later, if the glass transition temperature is less than 150 ° C., it becomes difficult to maintain the embossed shape, and the contact area with the sliding counterpart member increases. This is because the sliding resistance is further increased.

  As the thermosetting resin, for example, phenol resin, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, diallyl phthalate resin, polyamide resin, polyimide resin, polyamideimide resin or a mixture of these resins can be used. It is. Of these, phenol resins, epoxy resins, polyimide resins, and mixtures of these resins are preferably used from the viewpoints of heat resistance and rigidity.

(3) Lubricant The lubricant includes oil and grease, but it is preferable to use oil from the viewpoint of lubricity. The oil preferably does not contain solids such as molybdenum disulfide, and mineral oils, synthetic oils, silicone oils, fluorine oils, vegetable oils, and the like can be used. In the case of using a silicone-based oil, modified silicone oils such as amino-modified silicone oil, dimethyl silicone oil, mercapto-modified silicone oil, hindered amine oil and the like are preferable because of excellent slidability and durability. In this case, the viscosity (normal temperature) of the silicone oil is desirably 50 cps or more (more preferably 100 cps or more, more preferably 300 cps or more), 3000 cps or less (more preferably 1000 cps or less, more preferably 500 cps or less). . This is because if the viscosity is less than 50 cps, the evaporation of the silicone oil increases, and if the viscosity exceeds 3000 cps, the sliding resistance increases and the effect of using the lubricant cannot be obtained.

  As described above, the sliding member of the present invention is basically composed of a porous fluororesin film, a thermosetting resin, and a lubricant, but has excellent characteristics by adding the following features. The sliding member which has can be comprised.

  If the porous fluororesin film is embossed, the contact area between the sliding counterpart member and the sliding member can be reduced, so that the sliding resistance can be reduced. The embossed shape is not particularly limited, and a convex portion (concave portion) formed by embossing can take various forms such as a hemispherical shape, a weight shape, a rectangular shape, and a sine curve shape.

  The number of convex portions per unit area is preferably 200 pieces / square inch or more and 1000 pieces / square inch or less. This is because if it is less than 200 pieces / square inch, the contact area of the sliding surface increases and the sliding resistance increases. More preferably, it is 250 pieces / square inch or more, and further preferably, 300 pieces / square inch or more. On the other hand, the reason why the number is less than 1000 pieces / square inch is that the emboss density becomes too high when the number exceeds 1000 pieces / square inch, and scraps generated from the porous fluororesin film itself during actual use are trapped in the sliding member. This is because the sliding resistance becomes unstable. More preferably 900 pieces / square inch or less, and still more preferably 800 pieces / square inch or less.

2. Manufacturing method of sliding member The manufacturing method of the sliding member of the present invention includes (1) a step of producing a porous fluororesin film, and (2) a thermosetting resin in a part of the pores of the porous fluororesin film. And impregnating the thermosetting resin and (3) impregnating the porous fluororesin film with a lubricant.

(1) Production process of porous fluororesin film Conventionally known methods are used for producing the porous fluororesin film (for example, Japanese Patent Publication No. 51-18991, Japanese Examined Publication No. 56-45773, Japanese Patent Publication No. 56). Reference is made to JP-A-17216, JP-B-53-55378, JP-B-55-55379, JP-A-59-109534, JP-A-61-207446, JP-A-07-102413, etc. Become). As described above, a porous fluororesin film is formed by molding a paste obtained by mixing PTFE fine powder with a molding aid, removing the molding aid from the molded body, stretching, and firing if necessary. can get.

(2) Impregnation and curing step of thermosetting resin Next, the thermosetting resin is impregnated into a part of the holes of the obtained porous fluororesin film, and the thermosetting resin is cured. Since the pore shape of the porous fluororesin membrane is various and there are isolated and closed pores and those that are formed continuously, the “pore” in the present invention refers to the inside of the porous fluororesin membrane. Means a void. Therefore, in the present invention, “impregnating the thermosetting resin into some of the pores” means not completely impregnating the porous fluororesin film with the thermosetting resin, but leaving a part of the void. That means. That is, to leave a gap to be impregnated with a lubricant described later.

  In order to improve the adhesion between the porous fluororesin film and the thermosetting resin, it is effective to subject the porous fluororesin film to surface treatment prior to impregnation with the thermosetting resin. Examples of the surface treatment include dry surface treatment such as corona discharge treatment and plasma treatment, liquid ammonia treatment, and padding treatment using a surfactant. Among these, padding treatment using a surfactant is preferable because surface treatment can be easily performed up to the inside of the porous fluororesin film.

  In order to impregnate the pores of the porous fluororesin film with the thermosetting resin, the thermosetting resin can be dissolved and diluted in a solvent, or heated to be liquid (heated melt). However, since the heated melt is generally difficult to handle due to its high viscosity, a method of diluting with a solvent is suitable.

  In order to impregnate the pores of the porous fluororesin film with a thermosetting resin dissolved and diluted in a solvent, a method such as dipping or coating can be employed. If the surface treatment of the porous fluororesin film described above is performed, the impregnation operation becomes easier and more reliable.

  As a means for impregnating the thermosetting resin while leaving a part of the pores of the porous fluororesin film, for example, there is a method of adjusting the concentration of the thermosetting resin diluted with a solvent. This is because a part of the pores of the porous fluororesin film remains due to volatilization of the solvent.

  If the surface of the porous fluororesin film is impregnated so much that the thermosetting resin solution remains (coating level), the surface will be cured while the solvent evaporates when the solution is dried. The resin enters the pores of the porous fluororesin film and can be fully filled with the thermosetting resin. If the fact that the amount of the thermosetting resin to be filled is determined by the amount of the thermosetting resin solution to be coated on the surface of the porous fluororesin film is adjusted, if the coating amount is adjusted to a small amount, The thermosetting resin can be impregnated while leaving a part of the holes. Further, the amount of pores left can be adjusted by controlling the drying method.

  If all the pores of the porous fluororesin film are filled with thermosetting resin, the surface will become glossy when thermoset, or part of the thermosetting resin will be ball-shaped, so thermosetting resin It can be judged from the appearance that the impregnation of is excessive. If the impregnation amount of the thermosetting resin is excessive, the porous fluororesin film is not exposed on the surface of the sliding member, so that the sliding resistance becomes high and the ability to retain lubricating oil is poor and wears. It becomes easy.

  On the other hand, when the impregnation amount of the thermosetting resin is too small, a white spot pattern appears in a semi-cured (B-stage) state in which the solvent is volatilized and removed, so that it can be easily determined in appearance. When the amount of impregnation of the thermosetting resin is too small, the lubricating oil is excessively adsorbed on the insufficiently impregnated portion, so that the adsorbed lubricating oil is released under the actual operating environment of the image fixing device by thermal transfer, and the printed matter is soiled. To do. Further, since the reinforcement of the porous fluororesin film with the thermosetting resin is insufficient, the porous fluororesin film is deformed by a creep phenomenon and the sliding resistance is increased.

  Preferably, a part of the solvent in the porous fluororesin film is volatilized and removed to make a B stage, and then the periphery of the porous fluororesin film is fixed, and the material, shape and thickness of the porous fluororesin film are fixed. Heat shrinkage can be prevented by adjusting the heat treatment conditions (temperature and speed) according to the conditions.

(3) Lubricant impregnation step After the heat treatment, the porous fluororesin film impregnated with an appropriate amount of thermosetting resin is cut into an appropriate shape, and the remaining holes of the porous fluororesin film are lubricated with lubricating oil or After impregnating a lubricant such as grease, it can be put to practical use as a sliding member. Note that the order of the step of cutting the porous fluororesin film and the step of impregnating the oil can be appropriately switched in consideration of the functionality and the cost of the oil.

  As described above, the manufacturing method of the sliding member of the present invention has a basic configuration of a porous fluororesin film production process, a thermosetting resin impregnation / curing process, and a lubricant impregnation process. Furthermore, the manufacturing method of the sliding member which has the outstanding characteristic can be provided by adding the following structures.

  In order to further reduce the sliding resistance of the sliding member, it is preferable to emboss the sliding member as described above. A preferable step of embossing does not completely cure the thermosetting resin, but gives unevenness to the sliding member in a semi-cured (B stage) state. The embossing can be performed in the range of about room temperature to the curing temperature of the thermosetting resin. Even if embossing is performed in a cured state, the thermosetting resin is destroyed, so that the embossed shape is difficult to be imparted.

  Specifically, embossing is performed by pressing a sliding member in a B-stage state under a suitable temperature and pressure on a mold such as a flat plate, a roll, or a belt having a predetermined emboss shape (uneven shape) on the surface. The surface shape of the mold is copied. In a simple manner, using a hot plate press machine, an embossed shape is formed on the surface of the porous fluororesin film by hot pressing the porous fluororesin film between the rubber elastic cushion and the metal wire mesh. Can be granted. From the viewpoint of productivity, it is preferable to perform continuous processing using two male / female embossing rollers or an embossing belt.

  The pressing temperature is desirably a temperature not higher than the melting point of the porous fluororesin film, preferably not less than 20 ° C. (more preferably not less than 30 ° C., more preferably not less than 40 ° C.) lower than the melting point. This is because if the heat press treatment is performed at a temperature near the melting point or higher, the possibility of damaging the porous fluororesin film such as a hole is increased.

  The embossed sliding member is placed at room temperature or in a heated environment in order to further cure the thermosetting resin. At this time, it is preferable to fix the periphery of the porous fluororesin film and to prevent thermal shrinkage by adjusting the heat treatment conditions (temperature / speed) according to the material, shape and thickness of the porous fluororesin film. .

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

Example 1
PTFE fine powder (trade name: Polyflon F104) manufactured by Daikin Industries, Ltd. Hereinafter, the film may be simply referred to as “film”. This was cut into a size of 300 × 500 mm.

  Separately, a nonionic fluorosurfactant (trade name: F-480SF, manufactured by DIC Corporation) is dissolved in methyl ethyl ketone to prepare a solution having a concentration of 3%, and this is poured into a stainless steel vat for surface treatment. Prepared as a bath.

  The porous PTFE film was immersed in a surface treatment bath for 3 seconds, then pulled up, fixed to a stainless steel frame so as not to sag, and placed in a dryer at 150 ° C. for 10 minutes to remove the solvent by drying. .

  Next, 200 g of a naphthalene type epoxy resin (trade name: HP-4032, manufactured by DIC Corporation), 10 g of powder dicyandiamide (trade name: DICY7, manufactured by Japan Epoxy Resin Corporation), 2 g of 2-ethyl-4-methylimidazole, and 200 g of methyl ethyl ketone (manufactured by Wako Pure Chemical Industries, Ltd.) was placed in a stainless steel container and mixed and dispersed for 30 minutes with a mixer to prepare an epoxy resin solution. This was transferred to a stainless steel bat.

  The entire porous PTFE film surface-treated with the fluorosurfactant was slowly immersed in the epoxy resin solution sequentially from the end. After confirming that white spots were not visible on the porous PTFE film, the film was slowly pulled up from the end while pressing a doctor knife on both sides of the film. Next, the impregnated epoxy resin was B-staged by fixing it to a stainless steel frame so as not to sag and placing it in a 120 ° C. dryer for 10 minutes. Since the appearance of the obtained film was a matte surface and no white spots were observed, it was confirmed that there was no excess or deficiency in the impregnation amount of the epoxy resin.

  A B-staged epoxy resin-impregnated film is cut in half, one of which is fixed to a stainless steel frame and placed in a 180 ° C dryer for 3 hours to form a C-stage (fully cured). It was.

  Next, with the film fixed to a stainless steel frame, apply silicone oil (trade name: KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) with a brush on one side of the film with a brush and absorb the silicone oil for 10 minutes in a dryer at 150 ° C. I let you. Thereafter, excess silicone oil was wiped with a paper towel to obtain Sample 1 of the sliding member of the present invention.

(Example 2)
The other half of the B-staged epoxy resin-impregnated film in Example 1 is matched with a 0.23 mmφ × 30 mesh stainless steel mesh wire mold-released with a silicone resin, and a polyimide film having a thickness of 75 μm vertically. And a pressure of ² kg / cm ² was applied to the porous PTFE film with a hot plate press at 150 ° C. for 10 minutes, thereby obtaining a semi-cured film in which the uneven pattern of the stainless mesh wire mesh was copied. Thereafter, the film was fixed on a stainless steel frame and subjected to heat treatment at 180 ° C. for 3 hours in a dryer to form a C stage (completely cured).

  Next, with the film fixed to the stainless steel frame, apply silicone oil (trade name: KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) with a brush on one side of the film, put it in a dryer at 150 ° C. for 10 minutes, and add silicone oil. Was absorbed. Then, the surface of excess silicone oil was wiped with a paper towel to obtain Sample 2 of the sliding member of the present invention whose surface was embossed with irregularities.

(Example 3)
In Example 3, PTFE fine powder (trade name: Polyflon F104, manufactured by Daikin Industries, Ltd.) was used for paste extrusion, roll rolling, lubricant drying, stretching, and firing, and each process was uniaxially stretched by conventional methods. A porous PTFE film was prepared. This was cut into a size of 300 × 500 mm.

  Separately, a nonionic fluorosurfactant (trade name: F-480SF, manufactured by DIC Corporation) was dissolved in methyl ethyl ketone to prepare a 3% concentration solution, which was poured into a stainless steel vat for surface treatment. Prepared as a bath.

  The porous PTFE film was immersed in a surface treatment bath for 3 seconds, then pulled up, fixed to a stainless steel frame so as not to sag, and placed in a dryer at 150 ° C. for 10 minutes to remove the solvent by drying. .

  In addition, a phenol resin solution is prepared by putting 100 g of special thermosetting phenolic resin (trade name: Nikkatoru N-210, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and 50 g of methyl ethyl ketone into a stainless steel container and mixing and dispersing them in a mixer for 10 minutes. did. This was transferred to a stainless steel bat.

  The entire uniaxially stretched porous PTFE film surface-treated with the fluorosurfactant was slowly immersed in the phenol resin solution sequentially from the end. After confirming that white spots were not visible on the porous PTFE film, the film was slowly pulled up from the end while pressing a doctor knife on both sides of the film. Next, this was fixed to a stainless frame so as not to sag, and placed in a drier at 120 ° C. for 10 minutes to make the impregnated phenol resin into a B stage. Since the appearance of the obtained film was a matte surface and no white spots were observed, it was confirmed that there was no excess or deficiency in the amount of phenol resin impregnated.

  A B-staged phenol resin impregnated film is cut into half size, one of which is fixed to a stainless steel frame and placed in a 230 ° C drier for 2 hours for C-stage (complete curing). It was.

  Next, with the film fixed on the stainless steel frame, apply silicone oil (trade name: KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) with a brush on one side of the film, put it in a dryer at 150 ° C. for 10 minutes, and add silicone oil. Was absorbed. Thereafter, excess silicone oil was wiped with a paper towel to obtain Sample 3 of the sliding member of the present invention.

Example 4
Using the remaining half of the film impregnated with the B-staged phenol resin in Example 3 and matching the 0.23 mmφ × 30 mesh stainless steel mesh wire mold-released with the silicone resin, the thickness is 75 μm above and below. A polyimide film was placed, and a pressure of ² kg / cm ² was applied to the porous PTFE film with a hot plate press at 150 ° C. for 10 minutes, thereby producing a semi-cured film in which the uneven pattern of the stainless mesh wire mesh was copied. Thereafter, the film was fixed to a stainless steel frame and heat treated at 230 ° C. for 2 hours in a dryer to form a C stage (completely cured).

  Next, with the film fixed to the stainless steel frame, apply silicone oil (trade name: KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) with a brush on one side of the film, put it in a dryer at 150 ° C. for 10 minutes, and add silicone oil. Was absorbed. Then, the surface of excess silicone oil was wiped with a paper towel to obtain Sample 4 of the sliding member of the present invention having a surface with an embossed surface.

(Comparative Example 1)
A biaxially stretched porous PTFE film was produced in the same manner as in Example 1. Without impregnating with thermosetting resin, the porous PTFE film is fixed to a stainless steel frame, and silicone oil (trade name: KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to one side of the film with a brush. Then, heat treatment was performed at 150 ° C. for 10 minutes using a dryer. Further, silicone oil was absorbed into the film. Then, the surface of excess silicone oil was wiped with a paper towel to obtain Sample 5 of the sliding member.

(Comparative Example 2)
A uniaxially stretched porous PTFE film was produced in the same manner as in Example 3. Without impregnation with thermosetting resin, a polyimide film with a thickness of 75 μm was placed on top and bottom in accordance with a 0.23 mmφ × 30 mesh stainless steel mesh wire mold-released with silicone resin, and at 150 ° C. for 10 minutes. A pressure of ² kg / cm ² was applied to the porous PTFE film with a hot plate press to obtain a film in which the uneven pattern of the stainless mesh wire mesh was copied.

  Next, with the film fixed on the stainless steel frame, apply silicone oil (trade name: KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) with a brush on one side of the film, put it in a dryer at 150 ° C. for 10 minutes, and add silicone oil. Was absorbed. Thereafter, the surface of excess silicone oil was wiped with a paper towel to obtain Sample 6 of the sliding member.

(Comparative Example 3)
A sample was prepared in the same manner as in Example 1, but the pores of the porous PTFE film were not impregnated with silicone oil. This was designated as Sample 7.

(Comparative Example 4)
A sample was prepared in the same manner as in Example 4, but the porous PTFE film was not impregnated with silicone oil. This was designated as Sample 8.

(Comparative Example 5)
Commercially available glass cloth Teflon (trade name: FGF-500-4, manufactured by Chuko Kasei Co., Ltd.) was used as sample 9 as it was.

  The characteristics of samples 1 to 9 of the sliding members prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were measured under the following conditions 1 to 7. The results are shown in Table 1.

1. Thickness Measured with a dial thickness gauge (measured in a state where a load other than the main body spring load was applied using “SM-1201” manufactured by Teclock Corporation).

2. Porosity The porosity of the sample was calculated based on the above formula (1).

3. PTFE material / thermosetting resin mass ratio For samples (samples 1 to 4, 7, and 8) in which pores of a porous PTFE film were impregnated with thermosetting resin, per unit area of the unimpregnated portion and the impregnated portion By mass comparison, the mass ratio of the PTFE material and the impregnated resin in the impregnated portion was calculated.

4). Glass transition temperature (Tg)
The glass transition temperature of samples 1 to 8 was measured by a linear expansion coefficient (TMA tensile mode) in accordance with JIS K 7197.

5. Oil content Sliding member samples 1 to 9 were immersed in silicone oil (trade name: KF96, manufactured by Shin-Etsu Chemical Co., Ltd.), kept at 150 ° C. for 1 hour, taken out, and the surface was well wiped with a paper towel. When the mass of the sample is measured in this state, the difference from the original mass is the mass of the newly impregnated silicone oil. Based on the amount, the mass ratio of the silicone oil originally contained in Samples 1 to 9 was calculated as the oil content (mass%).

6). Static friction coefficient The static friction coefficient was measured using a surface property measuring instrument (trade name: HEIDON-14D, manufactured by Shinto Kogyo Co., Ltd.). In this test, a polyimide film (trade name: Upilex, manufactured by Ube Industries, Ltd.) thinly coated with the silicone oil KF96 was used as a sliding partner material. As can be seen from Table 1 below, the static friction coefficients of the samples 7 to 9 as comparative examples are not so bad as compared with the samples 1 to 4 as examples of the present invention. This is because oil is not used in Samples 7 to 9, and therefore there is no adhesion (sticking) effect due to oil. Since samples 2 and 4 are embossed, the adhesion effect due to oil is reduced, and the static friction coefficient is lower than those of samples 1 and 3.

7). Evaluation of actual machine Take out the free belt roll set in the unit of the image fixing device and paper reversing device of the color printer (trade name: DocuPrint-C1100, manufactured by Fuji Xerox Co., Ltd.), remove the felt for oil application, and soak with methyl ethyl ketone. The components placed inside the belt and the inner surface of the belt were thoroughly wiped with a dipped paper towel to remove the silicone oil. Samples 1 to 9, which were cut into the same shape as the attached sliding film, were attached instead and incorporated into the printer. Using this printer, after processing 200,000 sheets of A4 size paper, the state of the sliding member and the inner surface of the belt was observed.

  As can be seen from Table 1, in the samples 5 and 6 which were not impregnated with the thermosetting resin, the rotation of the endless belt was not smooth, so the test was stopped. In Samples 7 and 8, which were not impregnated with lubricant (silicone oil), abnormal noise was generated from the vicinity of the endless belt after passing 50,000 sheets. Was seen in large quantities. Further, in the glass cloth Teflon sample 9, the inner surface of the endless belt was glossy but had a streak. In addition, a large amount of white abrasion powder was generated, and the surface (contact portion) of the sliding member was smooth.

  On the other hand, in samples 1 to 4 which are sliding members in which the thermosetting resin and the lubricant are held in the pores of the porous fluororesin film, the inner surface of the endless belt is glossy and smooth. Moreover, although some abrasion powder was observed, the surface of the sliding member was glossy and smooth. In sample 2 and sample 4 subjected to embossing, some abrasion powder was observed in the recesses, but the printed image was excellent to the end.

  As described above, since the sliding member of the present invention does not include a glass cloth, it does not damage the endless belt that is the sliding counterpart member. Further, since the lubricating oil is contained in the sliding member itself, no additional parts are required for oil application, which contributes to downsizing of the image fixing device. Further, since a liquid film of lubricating oil is formed on the sliding surface, the amount of wear of the porous fluororesin film is small and the durability is excellent.

  Further, since the thermosetting resin is finely distributed in the matrix of the porous PTFE membrane having a fine structure, the thermosetting resin suppresses the creep phenomenon of the porous PTFE membrane having a low glass transition temperature, and the porous PTFE is reduced. Since the film covers the periphery of the thermosetting resin, the frictional resistance against the sliding member can be kept low.

Claims (8)

  A sliding member including a porous fluororesin film, wherein a thermosetting resin and a lubricant are held in the holes of the porous fluororesin film.   The sliding member according to claim 1, wherein the porous fluororesin film is embossed.   The sliding member according to claim 2, wherein the number density of convex portions formed on the porous fluororesin film by the embossing is 200 pieces / square inch or more.   The sliding member according to claim 1, wherein the porous fluororesin film is a polytetrafluoroethylene film.   The sliding member according to any one of claims 1 to 4, wherein the porosity of the porous fluororesin film is 40 to 95%.   The sliding member according to claim 1, wherein the lubricant is oil.   A method for manufacturing a sliding member, the step of producing a porous fluororesin film, the step of impregnating a thermosetting resin in a part of the pores of the porous fluororesin film, and curing the thermosetting resin. And a step of impregnating the porous fluororesin film with a lubricant.   The step of curing the thermosetting resin is a step of semi-curing the thermosetting resin, and then the step of embossing the porous fluororesin film and the step of further curing the thermosetting resin. The manufacturing method of the sliding member of Claim 7 which has these.