JP2013028059A - Multilayered sheet and endless belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a multilayered sheet excellent in bending resistance, heat resistance and non stickiness; and an endless belt comprising this multilayered sheet.SOLUTION: The multilayered sheet includes: at least one layer of a composite material layer comprising fluororesin and heat resistance fiber fabric; and the fluororesin layer made of lamination of a plurality of stretched fluororesin sheets. There are provided the multilayered sheets and the endless belts wherein the fluororesin layer is provided by lamination of fluororesin sheets so that the stretching directions of respective fluororesin sheets are different.

Description

  The present invention relates to a multilayer sheet and an endless belt excellent in bending resistance, heat resistance, and non-adhesiveness. More specifically, the present invention relates to a multilayer sheet excellent in bending resistance, non-adhesiveness, and heat resistance, which can be used for food and industry, for example, and an endless belt comprising the multilayer sheet.

  Conventionally, a heat-resistant multilayer sheet in which a heat-resistant fiber woven fabric having excellent heat resistance and tensile strength is laminated with a heat-resistant resin having excellent heat resistance and non-adhesiveness is known. The sheet is used as a food and industrial heat-resistant non-adhesive sheet, a heat-resistant non-adhesive transport belt, and the like (for example, see Non-Patent Document 1).

  As the heat resistant fiber woven fabric used for the heat resistant multilayer 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 multilayer sheet, fluororesins, such as polytetrafluoroethylene resin (PTFE), are used, for example.

  When the above heat-resistant multilayer sheet is used for a trough belt where bending resistance is important, the heat-resistant fiber woven fabric is a glass fiber heat-resistant multilayer sheet, which is weak in bending resistance, and the bent portion is torn early and damaged. There was a problem.

  Therefore, conventionally, when a heat-resistant multilayer sheet of aramid fibers, which is superior in bending resistance to glass fibers, is used, it is harder to break from the bent portion than glass fibers.

  Further, a trough belt using a woven fabric in which a glass fiber filament converging body having a thickness of 2.5 to 4.0 μm, which is superior in bending resistance to an aramid fiber, is used as a warp (Japanese Patent Laid-Open No. 7-284370) (Patent Document 1)) has been proposed.

JP 7-284370 A (Patent No. 3371332)

Published by Honda Sangyo Co., Ltd. Fluoropolymer conveyor belt catalog “Honda Flow Belt” “Max Liner Belt” “Honda Flow Fabric”

Fluoropolymers such as polytetrafluoroethylene resin (PTFE) have unique properties such as heat resistance, cold resistance, chemical resistance, non-adhesiveness, low friction coefficient, and electrical properties, It is known that since the viscosity is as high as 10 10 to ¹¹ Pa · s (380 ° C.), a melt molding method that is a general molding method cannot be applied.

  Therefore, in order to make the heat-resistant fiber woven fabric and the heat-resistant resin into a multi-layer, it is not easy to perform melt-molding processing. Therefore, the aqueous suspension of polytetrafluoroethylene resin (PTFE) particles has heat resistance. It is manufactured by impregnating and adhering a fiber woven fabric, drying, and firing.

  Therefore, even if the surface of the heat-resistant multilayer sheet is a woven fabric using the above-mentioned aramid fiber or glass fiber filament converging body having a thickness of 2.5 to 4.0 μm as warp yarn, the heat-resistant fiber A large number of pores are formed on the surface due to the influence of the woven state and surface state of the woven fabric.

  Therefore, when used on trough belts where bending resistance is important, damage is caused in the order of tearing from the pores of the polytetrafluoroethylene resin (PTFE) layer on the surface, exposure of the heat resistant fiber woven fabric, and tearing of the heat resistant fiber woven fabric Therefore, reduction of pores on the surface of the polytetrafluoroethylene resin (PTFE) layer and reinforcement of the polytetrafluoroethylene resin (PTFE) layer are problems.

  Therefore, as a method for improving such a problem, a method is proposed in which a skived film or sheet of polytetrafluoroethylene resin (PTFE) is wrapped and laminated in a U-shape on the surface or end of the heat-resistant multilayer sheet. ing.

  However, although the skived film or sheet has fewer pores than the heat-resistant multi-layer sheet, it does not contain a reinforcing base material, so that it is easy to shrink during lamination and to be easily broken when a hole is opened by sewing. there were.

  The present invention has been studied in view of the above circumstances, and is a multilayer having excellent bending resistance, heat resistance, and non-adhesiveness suitable for trough belts for which bending resistance is important for food and industry. It is to provide a seat and an endless belt.

  As a result of intensive studies in view of the above problems, the present inventor is difficult to form pores on the surface of the heat-resistant multilayer sheet, and the surface layer is reinforced, and when used for a trough belt in which flex resistance is important. In addition, the present inventors have found a multilayer sheet excellent in bending resistance, heat resistance and non-adhesiveness according to the present invention, in which the fluororesin of the surface layer is hardly broken and the service life can be improved.

  That is, the multilayer sheet according to the present invention includes a multilayer having at least one composite material layer composed of a fluororesin and a heat-resistant fiber woven fabric, and a fluororesin layer formed by laminating a plurality of stretched fluororesin sheets. It is a sheet | seat, Comprising: Each said fluororesin sheet is laminated | stacked so that the extending | stretching direction of each fluororesin sheet may differ, It is characterized by the above-mentioned.

  In addition, an 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.

  Further, another endless belt according to the present invention comprises (a) a plurality of stretched fluororesin sheets, and the fluororesin layers laminated so that the stretch directions of the respective fluororesin sheets are different from each other. A belt-shaped annular body formed of at least one composite material layer made of a resin and a heat-resistant fiber woven fabric is wrapped on one side or both sides of the annular body, or the side surface of the belt-shaped annular body is wrapped in a U-shape. And is formed.

  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 fluororesin layer formed by laminating a plurality of stretched fluororesin sheets. Since the fluororesin layer is formed by laminating the fluororesin sheets so that the stretching directions of the fluororesin sheets are different, pores on the surface of the heat-resistant multilayer sheet are formed. It is difficult and the surface layer is further strengthened, so even when used for trough belts for food and industry, the fluororesin of the surface layer is difficult to break, and the trough shape, which is a characteristic of trough belts, is impaired. In addition, the service life is improved without impairing the non-adhesiveness characteristic of the fluororesin transport belt.

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. 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 fluororesin layer formed by laminating a plurality of stretched fluororesin sheets. And each said fluororesin sheet is laminated | stacked so that the extending | stretching direction of each fluororesin sheet may differ, The said fluororesin layer is characterized by the above-mentioned.

  As a preferable specific example of such a multilayer sheet according to the present invention, for example, the one described in FIG.

  A multilayer sheet 1 according to the present invention shown in FIG. 1 is a fluororesin formed by laminating a single composite layer 2 composed of a fluororesin 2a and a heat-resistant fiber woven fabric 2b and a plurality of stretched fluororesin sheets. It is a multilayer sheet having the layer 3, wherein the fluororesin layer 3 is laminated with the fluororesin sheets so that the stretching directions of the fluororesin sheets are different.

  Although FIGS. 2-5 shows the preferable example of the endless belt 10 by this invention, it is not limited to this.

<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.

  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 by, for example, impregnating the heat-resistant fiber woven fabric with an 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 amount of the fluororesin used 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 is a multilayer sheet having at least one composite material layer composed of a fluororesin and a heat-resistant fiber woven fabric, and a fluororesin layer formed by laminating a plurality of stretched fluororesin sheets. is there.

  The laminating position of the fluororesin sheet can be laminated by wrapping the entire surface of the composite material layer, a bent portion, and an end portion in a U-shape, but is not limited to this, and is appropriately determined depending on the specific application, purpose, etc. Can be determined. As a result, it is possible to improve flexibility and suppress fuzz at the ends as required.

  In the present invention, the fluororesin is preferably polytetrafluoroethylene.

  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.

  The thickness of the surface layer of the fluororesin sheet is preferably 80 to 1700 μm, particularly preferably 80 to 230 μm.

As the fluororesin film or sheet, use of a commercially available “LFP ^™ CROSS FILM manufactured by Textiles coated international Inc” is optimal.

<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 multilayer sheet according to the present invention. The width, length, and the like of the endless belt can be appropriately determined according to the specific use of the endless belt.
2 to 5 show preferred embodiments of the endless belt according to the present invention.
The endless belt according to the present invention shown in FIG. 2 is one in which the other end is overlapped with the peripheral region of one end of the belt-like product of the multilayer sheet, and both ends are joined, as shown in FIG. The endless belt according to the present invention is obtained by joining two end portions of a belt-like material of a multilayer sheet at the end cross section, and the endless belt according to the present invention shown in FIG. The two end portions of the belt-like object are overlapped and joined to the same connecting sheet, and the endless belt according to the present invention shown in FIG. 5 has two endless belts shown in FIG. It has a joined structure.

  An endless belt according to the present invention is obtained by forming a belt-like material formed of at least one composite material layer made of the fluororesin and a heat-resistant fiber woven fabric into an annular body having a desired width and length according to the application. The fluororesin film or sheet can be laminated by wrapping the entire surface of the annular composite material layer, a bent part, and an end portion in a U-shape, but not limited thereto, depending on the specific application or purpose, etc. It can be determined as appropriate. As a result, it is possible to improve flexibility and suppress fuzz at the ends as required.

<Example 1>
(1) Multi-layer sheet using a composite material of fluororesin and aramid fiber woven fabric First, in order to obtain a composite material of fluororesin and aramid fiber, a plain-woven aramid fiber woven fabric (thickness 250 μm) is fluorinated with a continuous coating device. After impregnating and adhering to an aqueous suspension of resin (PTFE), drying at 80 ° C. and firing at a temperature of 380 ° C., a composite of fluororesin (PTFE) and aramid fiber woven fabric (thickness 350 μm) Obtained.

Next, a commercially available multi-directional laminated fluororesin (PTFE) film ((thickness 80 μm) (“LFP ^TM CROSS FILM” manufactured by Textiles coated International Inc) on the surface of the composite material (thickness 350 μm) of the fluororesin and aramid fiber woven fabric. (Product name))), and a multi-layered sheet (thickness) in which a multi-directional laminated fluororesin (PTFE) film layer is formed on both sides of a composite material of fluororesin and aramid fiber woven fabric by pressure bonding at a temperature of 380 ° C. 510 μm) was obtained (FIG. 1).

<Example 2>
(2) Multi-layer sheet using a composite material of fluororesin and glass fiber woven fabric First, in order to obtain a composite material of fluororesin and glass fiber woven fabric, a plain weave glass fiber woven fabric (thickness 250 μm) with a continuous coating device Is impregnated with an aqueous suspension of fluororesin (PTFE), adhered, dried at 80 ° C., fired at a temperature of 380 ° C., and a composite material (thickness 350 μm) of fluororesin (PTFE) and glass fiber woven fabric. )

Next, a commercially available multi-directional laminated fluororesin (PTFE) film ((thickness 80 μm) (“LFP ^TM CROSS FILM” manufactured by Textiles coated International Inc.) on the surface of the composite material (thickness 350 μm) of the fluororesin and glass fiber woven fabric. (Product name))), and a multi-layer sheet (thickness) in which a multi-directional laminated fluororesin (PTFE) film layer is formed on both surfaces of a composite material of a fluororesin and a glass fiber woven fabric by pressure bonding at a temperature of 380 ° C. 510 μm) was obtained (FIG. 1).

<Example 3>
(3) Endless belt using the multilayer sheet of Example 1 The multilayer sheet (thickness 510 μm) of Example 1 is cut and placed so as to be endless, and heat-sealed at a temperature of 380 ° C. with a heating press. Thus, an endless belt was obtained (FIG. 2).

<Example 4>
(4) Endless belt using the multilayer sheet of Example 2 The multilayer sheet (thickness 510 μm) of Example 2 was cut and placed so as to be endless, and heat-sealed at a temperature of 380 ° C. with a heating press. Thus, an endless belt was obtained (FIG. 2).

<Example 5>
(5) Endless belt in which a fluororesin film is laminated on the endless belt of the composite material of Example 1 The composite material (thickness 350 μm) of the fluororesin and aramid fiber woven fabric of Example 1 is endless in the same manner as in Example 3. Multi-directional laminated fluororesin (PTFE) film ((thickness 80μm) (Textiles coated international Inc. "LFP ^TM CROSS FILM" (trade name))). Were placed and pressure-bonded at a temperature of 380 ° C. to obtain an endless belt.

<Example 6>
(6) Endless belt in which a fluororesin film is multilayered on the endless belt of the composite material of Example 2 The composite material (thickness 350 μm) of the fluororesin and glass fiber woven fabric of Example 2 was endless in the same manner as in Example 3. Multi-directional laminated fluororesin film (PTFE) ((Thickness 80μm) (“LFP ^TM CROSS FILM” (trade name)) manufactured by Textiles coated international Inc.) Were placed and pressure-bonded at a temperature of 380 ° C. to obtain an endless belt.

<Example 7>
(7) Endless belt in which both ends of the endless belt of the composite material of Example 1 are layered with a fluororesin film The composite material (thickness 350 μm) of the fluororesin and aramid fiber woven fabric of Example 1 is the same as Example 3. The endless belt is made into a multi-directional laminated fluororesin (PTFE) film ((80 μm thick) (“LFP ^TM CROSS FILM” (trade name) manufactured by Textiles coated international Inc.)) It was wrapped and arranged in a letter shape and pressure-bonded at a temperature of 380 ° C. to obtain an endless belt.

<Example 8>
(8) Endless belt in which both ends of the endless belt of the composite material of fluororesin and glass fiber woven fabric of Example 2 are layered with the fluororesin film The thickness of the composite material of Example 2 (thickness 350 μm) is the same as that of Example 3. The endless belt is made into a multi-directional laminated fluororesin (PTFE) film ((80 μm thick) (“LFP ^TM CROSS FILM” (trade name) manufactured by Textiles coated international Inc.)) It was wrapped and arranged in a letter shape and pressure-bonded at a temperature of 380 ° C. to obtain an endless belt.

<Comparative Example 1>
In the same manner as in Example 1, a fluororesin (PTFE) skived single film (thickness 80 μm) was pressure-bonded instead of the multi-directional laminated fluororesin (PTFE) film, but the fluororesin (PTFE) skived single film was severely contracted and endless. A possible multilayer sheet was not obtained.

<Comparative example 2>
A fluororesin (PTFE) skived single film (thickness 80 μm) was pressure-bonded in place of the multi-directional laminated fluororesin (PTFE) film in the same manner as in Example 2, but the shrinkage of the fluororesin (PTFE) skived single film was severe and endless. A possible multilayer sheet was not obtained.

<Comparative Example 3>
The composite material (thickness 350 μm) of the fluororesin and aramid fiber woven fabric of Example 1 was made into an endless belt by the same method as in Example 3.

<Comparative example 4>
The composite material (thickness 350 μm) of the fluororesin and glass fiber woven fabric of Example 2 was made into an endless belt by the same method as in Example 3.

<Comparative Example 5>
The composite material (thickness 350 μm) of the fluororesin and aramid fiber woven fabric of Example 1 was made into an endless belt by the same method as in Example 3, and a fluororesin (PTFE) skived single film (thickness 80 μm) in the length direction of both ends. ) Was wrapped in a U-shape in the same manner as in Example 7 to obtain an endless belt.

<Comparative Example 6>
The composite material (thickness 350 μm) of the fluororesin and glass fiber woven fabric of Example 2 was made into an endless belt by the same method as in Example 3, and a fluororesin (PTFE) skived single film (thickness 80 μm) in the length direction of both ends. ) Was wrapped in a U-shape in the same manner as in Example 8 to obtain an endless belt.

<Comparative Example 7>
Another fluororesin (PTFE) produced by the same method as in Example 1 at both ends where the composite material (thickness 350 μm) of the fluororesin and aramid fiber woven fabric of Example 1 was made into an endless belt by the same method as in Example 3. And an aramid fiber woven composite material (thickness: 210 μm) were wrapped in a U shape to form an endless belt.

<Comparative Example 8>
Another fluororesin (PTFE) produced by the same method as in Example 1 at both ends where the composite material (thickness 350 μm) of the fluororesin and glass fiber woven fabric of Example 2 was made into an endless belt by the same method as in Example 4. And an aramid fiber woven composite material (thickness: 210 μm) were wrapped in a U shape to form an endless belt.

[Evaluation]
Bending test Endless belts obtained in Examples 3 to 6 and Comparative Examples 3 to 4 are set in a running test machine provided with a jig so that a crease is formed in the vertical direction, and the appearance changes after bending 300,000 times. Were comparatively tested.
The test conditions were speed: 125 m / min, roll diameter: φ80 mm, and test material tension: 0.5 kg / cm. The results are shown in Table 1.

Fluff test The endless belts obtained in Examples 7 to 8 and Comparative Examples 5 to 8 were set on a running test machine, and the appearance change after 1000000 bending at both ends was comparatively tested.
The test conditions were speed: 40 m / min, roll diameter: φ20 mm, and test material tension: 0.8 kg / cm. The results are shown in Table 2.

DESCRIPTION OF SYMBOLS 1 Multi-layer sheet 2 Composite material layer 2a Fluororesin 2b Heat-resistant fiber woven fabric 3 Fluororesin laminate 10 Endless belt

Claims (3)

A multilayer sheet having at least one composite layer composed of a fluororesin and a heat-resistant fiber woven fabric, and a fluororesin layer formed by laminating a plurality of stretched fluororesin sheets,
Each of the fluororesin layers is a laminate sheet in which the fluororesin sheets are laminated so that the extending directions of the fluororesin sheets are different.   An endless belt comprising an annular body of a belt-like material formed from the multilayer sheet according to claim 1.   (A) A fluororesin layer composed of a plurality of stretched fluororesin sheets and laminated so that each fluororesin sheet has a different stretching direction is at least one layer composed of (b) a fluororesin and a heat-resistant fiber woven fabric. Characterized in that it is formed on one or both sides of the annular body of the belt-like material formed from the composite material layer, or so as to wrap the side surface of the annular body of the belt-like material in a U-shape, Endless belt.

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