JP2011068133A - Double-layer sheet, endless belt and method for producing the belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-layer sheet excellent in heat resistance, non-adhesiveness, wear resistance and gripping properties, an endless belt comprising the double-layer sheet and a method for producing the endless belt. <P>SOLUTION: The double-layer sheet has at least one composite material layer comprising a fluorocarbon resin and a heat-resistant fiber woven fabric and a surface layer comprising a polyimide-based resin. The surface layer is formed while interposing a treated surface, which is formed by activating the surface of the composite material layer, between the surface layer and the composite material layer. The endless belt and the method for producing the endless belt are also provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multilayer sheet, an endless belt, and a method for producing the same. More specifically, the present invention relates to a multilayer sheet excellent in heat resistance, non-adhesiveness and wear resistance, and grip, which can be used for industrial use, an endless belt comprising the multilayer sheet, and a method for producing the same. It is.

  Conventionally, heat-resistant composite sheets are known in which a heat-resistant fiber woven fabric excellent in heat resistance and tensile strength is combined with a heat-resistant resin excellent in heat resistance and non-adhesiveness. They are used as related heat-resistant non-adhesive sheets and heat-resistant non-adhesive transport belts.

  As the heat resistant fiber woven fabric used for the heat resistant composite sheet, for example, a woven fabric in which glass fiber, aramid fiber or the like is plain woven or twill woven is used.

  Moreover, as heat resistant resin used for the said heat resistant composite sheet, fluororesins, such as polytetrafluoroethylene resin (PTFE), are used, for example.

However, in general, fluororesin is excellent in heat resistance, cold resistance, non-adhesiveness, chemical resistance, combustion resistance, weather resistance, electrical insulation, low friction, etc., but poor in wear resistance. In addition, there is a problem that it is easy to slip because of its excellent low friction property.
Examples of heat-resistant materials that are superior to fluororesins in abrasion resistance, inferior in low friction, excellent in grip properties, and difficult to slip include polyimide resins.

  As a method for producing a sheet having improved wear resistance, for example, a heat-resistant fiber woven fabric is impregnated and adhered to a mixed solution in which a polyimide resin is dispersed in an aqueous fluororesin suspension, dried, and then fired. (Japanese Patent Laid-Open No. 2006-21403 (Patent Document 1)) has been proposed.

  However, since the sheet described in Patent Document 1 is a mixed material of a polyimide resin and a fluororesin, both performances are averaged, and it is possible to obtain the original excellent wear resistance of the polyimide resin. It seems difficult. In endless belts for conveyance, it is important that the inner surface of the belt, which is the contact surface with the drive roll, has an appropriate grip and wear resistance. However, it is a mixed material of polyimide resin and fluororesin. So it seems difficult to achieve both.

  Tubular endless belts that form a layer of polyimide resin and fluororesin that is not a mixture of polyimide resin and fluororesin (Japanese Patent Laid-Open No. 7-110632 (Patent Document 2), Japanese Patent Laid-Open No. 7-178741 (Patent Document) 3) and JP-A-2002-178422 (Patent Document 4)) have also been proposed. However, the manufacturing method is molding with a cylindrical mold, and the equipment cost seems to increase in order to cope with various dimensions.

JP 2006-21403 A JP-A-7-110632 JP 7-178741 A JP 2002-178422 A

  The present invention has been studied in view of the above circumstances, and obtains a sheet having excellent heat resistance and non-adhesiveness as well as necessary wear resistance and grip properties, and cuts them into necessary dimensions. It is an object of the present invention to provide a multi-layer sheet capable of producing endless belts of various dimensions without using a mold, an endless belt composed of the multi-layer sheet, and a method for producing the same.

  The multilayer sheet according to the present invention is a multilayer sheet having at least one composite material layer composed of a fluororesin and a heat-resistant fiber woven fabric and a surface layer composed of a polyimide resin, wherein the surface layer is composed of the composite sheet. It is characterized by being formed through a treated surface formed by a surface activation treatment performed on the material layer.

  Such a multilayer sheet according to the present invention includes, as a preferred embodiment, one in which the surface activation treatment is silica particle adhesion firing treatment, metal sodium etching treatment, plasma discharge treatment or corona discharge treatment.

  In addition, an endless belt according to the present invention is characterized in that it is composed of an annular body of a belt-like material formed from the above multilayer sheet.

And the manufacturing method of the endless belt according to the present invention cuts the multilayer sheet into a belt shape, and joins two opposing ends of the belt-shaped object of the multilayer sheet to obtain an annular body. It is a feature.

  Further, another endless belt manufacturing method according to the present invention includes a belt-like material in which the multilayer sheet and another sheet are laminated, and two opposite ends of the belt-like material with respect to the multilayer sheet. And the two opposite ends of the belt and the other sheet of the belt-like material are joined or arranged close to each other to obtain an annular body.

  ADVANTAGE OF THE INVENTION According to this invention, the multilayer sheet | seat which has the outstanding heat resistance, non-adhesiveness and abrasion resistance, and grip property can be obtained.

  Since this multilayer sheet has a polyimide resin as its surface layer, it is possible to obtain non-adhesiveness, wear resistance, grip properties and the like suitable for the desired use and required performance.

  And according to the present invention, this multilayer sheet or a laminate of other sheets is formed so that an endless belt having a desired width and length can be formed as it is or after laminating other sheets. Since an endless belt can be obtained by cutting the belt into a belt shape, an endless belt having a desired width, length, and layer configuration according to the application can be easily manufactured. Prior to lamination, each layer having a desired width and length is prepared, and after these are laminated, an endless belt can be manufactured.

  In some cases, a wide endless belt is once formed without cutting the same multilayer sheet, and then the wide endless belt is cut to a desired width. A plurality of products can be manufactured at the same time. It is also easy to make different endless belts with different widths by adjusting the width when cutting the wide endless belt.

  And since the formation of the surface layer of the multilayer sheet can be carried out by applying a polyimide resin, the surface layer is obtained in comparison with the case where the surface layer portion is obtained in the form of a sheet in advance and laminated with an adhesive or the like. Therefore, it is possible to obtain a multilayer sheet and an endless belt excellent in strength and durability, and to easily and efficiently manufacture the multilayer sheet and the endless belt.

Sectional drawing which shows the structure of the multilayer sheet | seat by this invention. Sectional drawing which shows the structure of the multilayer sheet | seat by this invention. Sectional drawing which shows the structure of the endless belt by this invention. Sectional drawing which shows the structure of the endless belt by this invention.

  The multilayer sheet according to the present invention is a multilayer sheet having at least one composite material layer composed of a fluororesin and a heat-resistant fiber woven fabric and a surface layer composed of a polyimide resin, wherein the surface layer is composed of the composite sheet. It is characterized by being formed through a treated surface formed by a surface activation treatment performed on the material layer.

  Preferable specific examples of the multilayer sheet according to the present invention include those described in FIGS.

  A multilayer sheet 10 according to the present invention shown in FIG. 1 is a multilayer sheet having a single composite layer 2 composed of a fluororesin 2a and a heat-resistant fiber woven fabric 2b and a surface layer 3a composed of a polyimide resin. Thus, the surface layer 3a is formed through a treated surface 4 formed by a surface activation treatment performed on the composite material layer 2.

  The multilayer sheet 11 according to the present invention shown in FIG. 2 has a surface layer made of a polyimide resin on both sides of the multilayer sheet, and is a single layer made of a fluororesin 2a and a heat resistant fiber woven fabric 2b. A multi-layer sheet having a composite material layer 2 and a surface layer 3a made of a polyimide resin, wherein the surface layer 3a is formed by a surface activation treatment performed on the composite material layer 2 4 is formed.

<Composite layer>
The composite material layer in the multilayer sheet according to the present invention comprises a fluororesin and a heat resistant fiber woven fabric.

  The fluororesin in the present invention is not limited, but is polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP). And a heat resistant resin selected from the group consisting of: Of these, polytetrafluoroethylene is particularly preferred.

  The fluororesin can be mixed with conductive powder as necessary. As a result, it is possible to impart or improve conductivity and improve wear resistance. Preferable specific examples of the conductive powder include carbon black and titanium oxide. The blending amount is preferably 1 to 20 parts by mass with respect to the fluororesin.

  In the present invention, the heat-resistant fiber woven fabric includes, but is not limited to, glass fiber and aramid fiber. The thickness of the heat resistant fiber woven fabric is generally 30 to 1000 μm, particularly preferably 30 to 700 μm.

  Such a composite material layer can be preferably formed, for example, by impregnating the heat-resistant fiber woven fabric with the aqueous suspension of the fluororesin particles, drying, and firing. As the solvent for preparing the aqueous suspension, for example, water, particularly pure water is preferable. The amount of the fluororesin particles in the aqueous suspension is preferably 20 to 60 parts by mass, particularly 30 to 60 parts by mass with respect to 100 parts by mass of the solvent.

  In the composite material layer of the present invention, it is preferable that the fluororesin sufficiently penetrates into the inside of the heat resistant fiber woven fabric, and the surface of the heat resistant fiber woven fabric is covered with the fluororesin. Therefore, the application amount of the fluororesin is preferably 30 to 70 parts by mass, particularly 40 to 60 parts by mass, where the total amount of the heat resistant fiber woven fabric and the fluororesin is 100 parts by mass.

<Surface layer>
The multilayer sheet according to the present invention has a surface layer made of a polyimide resin.

  In the present invention, the polyimide resin is not limited. For example, polyimide and polyamideimide are preferable, and polyimide is particularly preferable.

  In the present invention, when the surface layer is formed by coating, a liquid polyimide varnish can be used to facilitate the coating, and a solvent can be blended if necessary. Thereby, viscosity can be reduced and coating property can be improved.

Moreover, electroconductive powder can be mix | blended with a polyimide resin as needed. As a result, for example, it is possible to impart or improve conductivity and thermal conductivity and improve wear resistance.

  The surface layer can be formed by applying the polyimide resin to the surface activation-treated surface of the composite material layer, drying it, and firing it. The firing temperature of the polyimide resin is preferably 300 to 400 ° C, particularly preferably 330 to 370 ° C.

  The thickness of the surface layer can be appropriately determined depending on the specific use and purpose of the multilayer sheet and endless belt according to the present invention. For example, if it shows about the multilayer sheet for endless belt manufacture especially suitable for conveyance use, 1-50 micrometers is preferable and, as for the thickness of a polyimide resin surface layer, 5-20 micrometers is especially preferable.

<Surface activation treatment>
In the multilayer sheet according to the present invention, the surface layer is formed via a treated surface formed by a surface activation treatment performed on the composite material layer. Here, the surface activation treatment means that the surface tension of the composite material layer is reduced by treating the fluororesin on the surface of the composite material layer according to the present invention to reduce the surface tension. The process which enables joining with the polyimide-type resin formed as above, and expresses sufficient joining strength. If this surface activation treatment is not performed, a surface layer made of a polyimide resin cannot be formed on the composite material, and the object of the present invention cannot be achieved.

  Examples of the preferable surface activation treatment in the present invention include silica particle adhesion firing treatment, metal sodium etching surface treatment, plasma discharge treatment, and corona discharge treatment. Among these, silica particle adhesion firing treatment is particularly preferable.

  Here, the detail of the surface activation process in this invention is shown below.

  Silica particle adhesion firing treatment: After applying a mixed aqueous suspension of silica particles and fluororesin particles to a composite material composed of fluororesin and heat-resistant fiber woven fabric, the surface of the composite material is made hydrophilic by firing treatment. Improve the processing.

  Metal sodium etching surface treatment: Treatment to improve the hydrophilicity of the composite material surface by applying a metal sodium solution to the composite material made of fluororesin and heat-resistant fiber woven fabric.

  Plasma discharge treatment: Treatment for improving the hydrophilicity of the composite material surface by performing glow discharge treatment on the surface of the composite material made of fluororesin and heat-resistant fiber woven fabric.

  Corona discharge treatment: A treatment for improving the hydrophilicity of the surface of the composite material by applying a corona discharge treatment to the surface of the composite material made of a fluororesin and a heat-resistant fiber woven fabric.

  The surface activation treatment is preferably performed on the entire surface of the composite material layer where the surface layer is formed, but it is performed on a portion of the composite material layer where the surface layer is formed. You can also.

  By performing such surface activation treatment, the contact angle (JIS K6768) when pure water is dropped on the fluororesin surface of the composite layer surface is significantly reduced. The contact angle which was about 106 ° before the surface activation treatment was changed to 80 to 90 ° by the silica particle adhesion baking treatment, 50 to 60 ° for the metal sodium etching surface treatment, and 50 to 60 ° by the plasma discharge treatment. Drop to.

<Endless belt>
The endless belt according to the present invention is characterized by comprising an annular body of a belt-like material formed from the above multilayer sheet. Therefore, the endless belt according to the present invention has excellent characteristics of the multilayer sheet, for example, excellent heat resistance, shape stability, non-adhesiveness and durability based on a composite material layer mainly composed of a fluororesin and a heat-resistant fiber woven fabric. And various characteristics (for example, wear resistance, heat resistance, durability) based on the polyimide resin as the surface layer.

  The method for producing an endless belt according to the present invention is characterized in that the multilayer sheet is cut into a belt shape, and two opposite ends of the belt-like object of the multilayer sheet are joined to obtain an annular body. And In addition, this annular body is formed by, for example, (b) overlapping and joining the other end to the peripheral region of one end of the belt-like material of the multilayer sheet (FIG. 3A), ) By firmly joining the two end portions of the belt-like material of the multilayer sheet at the end section (FIG. 3B), (c) the two end portions of the belt-like material of the multilayer sheet It can be obtained by bonding both to the same connecting sheet (FIG. 3C). The two ends can be joined by heat fusion or using an adhesive.

  Further, another endless belt manufacturing method according to the present invention includes a belt-like material in which the multilayer sheet and another sheet are laminated, and two opposite ends of the belt-like material with respect to the multilayer sheet. And the two opposite ends of the belt and the other sheet of the belt-like material are joined or arranged close to each other to obtain an annular body. Here, as another sheet laminated | stacked on said multilayer sheet, the sheet | seat which consists of a single layer or a some layer can be mentioned. In addition, as this other sheet | seat, a single layer and a multilayer sheet | seat can be used. Such other sheets include, for example, the composite material 2 and the multilayer sheets 10 and 11 described above.

FIG. 4 shows a preferred embodiment of such an endless belt according to the present invention. The endless belt 12 according to the present invention shown in FIG. 4 has the multilayer sheet 10 shown in FIG. 1 on the outer peripheral side and the other sheet 5 on the inner peripheral side. A sheet having the same contents as the composite material layer 2 is used. In the endless belt 12 according to the present invention, two opposing ends of the multilayer sheet 10 and two opposing ends of the belt-like material with respect to the other sheet 5 are positioned at positions 6 and 7, respectively. An endless belt is obtained by joining or closely arranging to obtain an annular body.
Note that the endless belt according to the present invention includes a multilayer sheet 10 shown in FIG. 1 on the inner peripheral side and another sheet 5 on the outer peripheral side as a preferable specific example.

  In the present invention, an endless belt having a desired width, length, and layer configuration can be easily obtained, unlike a method of manufacturing an endless belt using a seamless tubular product manufactured by a conventional mold or the like. Can be manufactured.

  In some cases, a wide endless belt is once formed without cutting the same multilayer sheet, and then the wide endless belt is cut to a desired width. A plurality of products can be manufactured at the same time. It is also easy to make different endless belts with different widths by adjusting the width when cutting the wide endless belt.

  The laminated sheet of the multilayer sheet and the other sheet according to the present invention is preferably obtained by heat-sealing the multilayer sheet and the other sheet, but the multilayer sheet and the other sheet are bonded with an adhesive. To obtain a laminated sheet.

<Example A1>
(1) A multilayer sheet in which a polyimide resin surface layer is formed on one side of a composite material. First, in order to obtain a composite material of a fluororesin and glass fiber, the thickness of the plain weave glass fiber cloth (95 μm) is measured with a continuous coating device. An aqueous suspension of PTFE) was impregnated and adhered, dried at 80 ° C., and then fired at a temperature of 350 ° C. to obtain a composite material of fluororesin and glass fiber (thickness: 135 μm).

  Next, in order to perform surface activation treatment on the composite material of fluororesin and glass fiber, 100 mass parts of an aqueous suspension of PTFE resin is mixed with 100 mass parts of an aqueous suspension of silica, and a surface activation treatment liquid is mixed. Got.

  Next, a surface activation treatment liquid is applied and adhered to one side of a fluororesin / glass fiber composite material with a continuous coating apparatus, dried at 80 ° C., and then baked at a temperature of 350 ° C. to attach silica. The surface activation treatment layer was obtained by firing.

  Next, in order to obtain a liquid polyimide varnish, 100 parts by mass of a solvent (dimethylacetamide (DMAC)) is mixed with 100 parts by mass of a commercial product (“Toray Nice # 3000” (trade name) manufactured by Toray Industries, Inc.), and the viscosity is 50 Cp. A liquid polyimide varnish was obtained.

  Next, the liquid polyimide varnish is applied and adhered to the surface activated surface of the composite material (thickness 135 μm) of the fluororesin and glass fiber using a continuous coating apparatus, dried at 80 ° C., and 350 Firing at a temperature of 0 ° C. yielded a multilayer sheet (thickness 140 μm) in which a polyimide resin surface layer was formed on one side of a fluororesin and a glass fiber composite (FIG. 1).

  The fluororesin layer surface of the composite material obtained as described above was compared with the polyimide resin layer surface of the multilayer sheet by the following evaluation method. The evaluation results are shown in Table 1.

1) Wear test: Executed according to JIS H8682-1. (Measured using a Suga Abrasion Tester at a speed of 2.4 m / min, a load of 350 gf, a test count of 1000 times, a wear wheel (diameter 50 mm, width 12 mm) as a mating material, and # 4000 water-resistant film.)
2) Coefficient of friction: Measured according to JIS K7218. (Measured using a friction wear tester manufactured by Orientec Co., Ltd., using a SUS304 ring as the mating material, with a sliding speed of 50 mm / S, a load of 20 N, a test time of 30 minutes.)
3) Contact angle: implemented in accordance with JIS K6768. (Measured using contact angle meter CA-D manufactured by Kyowa Interface Chemical Co., Ltd.) using distilled water as a test solution.

  From the above evaluation results, the polyimide resin is superior in wear resistance, non-adhesiveness, and low friction than the fluororesin. From this result, it was found that the polyimide resin is less likely to wear and slip than the fluororesin.

  For the structure of Example A1, it is preferable to use a fluorine resin surface on the workpiece side where non-adhesiveness is important and grip performance is not important, and a polyimide resin surface on the workpiece non-contact side where wear resistance and grip properties are important. There is, but is not limited to.

<Example A2>
(2) Multi-layer sheet having polyimide resin surface layers formed on both sides of the composite material A multi-layer sheet was obtained in the same manner as in Example A1. Surface activation treatment and formation of a polyimide resin surface layer are performed on the surface of the multilayer sheet on which the polyimide resin surface layer is not formed in the same manner as in Example A1, and the polyimide resin surface is formed on both surfaces of the composite material. A multilayer sheet (thickness: 145 μm) on which a layer was formed was obtained (FIG. 2).

  The structure of Example A2 is suitable for use in applications where wear resistance and grip properties are important and non-tackiness is not important, but is not limited thereto.

<Example A3>
(3) Endless sheet by laminating the multi-layer sheet of Example A1 and other sheets and the multi-layer sheet (thickness 140 μm) of endless belt example A1, fluororesin and glass fiber composite (thickness 135 μm). The endless belts (thicknesses) with the fluororesin layer surfaces stacked on each other and heat-sealed at a temperature of 350 ° C. with a hot press machine to form a fluororesin surface layer on one side and a polyimide resin surface layer on the other side 275 μm) was obtained (FIG. 4).

  In the structure of the endless belt of Example A3, the non-adhesiveness is important, the fluororesin surface is applied to the work side where slip is not important, and the work roll non-contact side where the wear resistance and grip are important is polyimide. The use of a resin surface is preferred but not limiting.

<Example A4>
(4) Double-sided polyimide resin endless belt obtained by laminating two multilayer sheets of Example A1 Two belts of the multilayer sheet (thickness 140 μm) of Example A1 were prepared, and the fluororesin layer surfaces were made to be endless. Was laminated by heat fusion at a temperature of 350 ° C. with a heating press, and an endless belt (thickness: 280 μm) having a polyimide resin surface layer formed on both sides was obtained (FIG. 4).

  The structure of the endless belt of Example A4 is suitable for use in applications where wear resistance and grip properties are important and non-stickiness is not important, but is not limited thereto.

  As in Examples A1 to A4 above, non-adhesiveness, abrasion resistance, and grip properties are imparted as necessary, and cut to the required dimensions and endless, without using a mold, etc. It is possible to provide a highly functional multilayer sheet having heat resistance, wear resistance, non-adhesiveness and grip properties, and a transport belt comprising this multilayer sheet, which can produce an endless belt capable of meeting the above requirements.

<Comparative Example A1>
Although the liquid polyimide varnish was applied to the multilayer sheet of Example A1 without performing surface activation treatment, the multilayer sheet could not be bonded and a usable multilayer sheet having sufficient bonding strength could not be obtained.

<Examples C1-C4>
In Examples A1 to A4, the multilayer sheet C1 according to the present invention was used in the same manner as in Examples A1 to A4 except that the surface activation treatment layer was formed by performing a metal sodium etching treatment instead of the silica adhesion baking treatment. , C2 and endless belts C3 and C4 were obtained.

<Examples D1 to D4>
In Examples A1 to A4, multilayer sheets D1 and D2 according to the present invention were used in the same manner as in Examples A1 to A4, except that the surface activation treatment layer was formed by performing plasma treatment instead of silica adhesion baking treatment. And endless belts D3 and D4 were obtained.

<Joint strength test>
For the polyimide surface layer of each multilayer sheet obtained by Examples A1 to A4, Examples C1 to C4 and Examples D1 to D4, a cross cut test (1 mm × 100 mm) in accordance with JIS H5400 However, the number of squares peeled off from the multilayer sheet was 0 in any multilayer sheet. On the other hand, in Comparative Example A1 in which the surface activation treatment layer was not performed, the number of cells that were peeled off was 100. The evaluation results are shown in Table 2.

DESCRIPTION OF SYMBOLS 10, 11 Multi-layer sheet 2 Composite material layer 2a Fluororesin 2b Heat-resistant fiber woven fabric 3a Surface layer 4 made of polyimide resin 4 Treated surface 5 Other sheet 12 Endless belt

Claims (5)

  A multi-layer sheet having at least one composite material layer made of a fluororesin and a heat-resistant fiber woven fabric and a surface layer made of a polyimide-based resin, wherein the surface layer is formed on the composite material layer. A multilayer sheet formed through a treatment surface formed by an activation treatment.   The multilayer sheet according to claim 1, wherein the surface activation treatment is an inorganic particle adhesion firing treatment, a metal sodium etching treatment, a plasma discharge treatment, or a corona discharge treatment.   An endless belt comprising an annular body of a belt-like material formed from the multilayer sheet according to claim 1.   A method for producing an endless belt, comprising: cutting the multilayer sheet according to claim 1 into a belt shape, and joining two opposite ends of the belt-like material of the multilayer sheet to obtain an annular body. .   A belt-like material in which the multilayer sheet according to claim 1 and another sheet are laminated, two opposite ends of the belt-like material with respect to the multilayer sheet and the other sheet of the belt-like material. A method for producing an endless belt, characterized in that two end portions facing each other are joined or arranged close to each other to obtain an annular body.

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