JP2003082330A - Seal material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torus seal material which imposes less burden to a user in the scene of use and can utilize materials effectively without waste. SOLUTION: The torus seal material is made of a belt-like oriented porous polytetrafluoroethylene body, and slits are cut in the longitudinal direction of the belt-like oriented porous polytetrafluoroethylene body. The slits are so cut that the belt-like oriented porous polytetrafluoroethylene body may be transformed into a window-frame shape by expanding it in the width direction. The length of cut of the slits is preferably so set that the ends in the longitudinal direction, which are valley-folded when the body is expanded to the window- frame shape, may substantially be joined to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ring-shaped, square-shaped, or polygonal-shaped sealing material used for sealing flange portions of pipes and containers, manhole covers of tanks, and other surface contact portions of industrial equipment. Or, it relates to a sealing material used to improve the airtightness between the intake hole of the fan cover and the fan in the electric blower to prevent the generation of a circulation flow. The present invention relates to a sealing material that is used by being deformed into a window frame shape such as an annular shape at the site of use.

[0002]

2. Description of the Related Art Pharmaceuticals,
In the field of food, chemistry, etc., a sealing material made of polytetrafluoroethylene (PTFE) having excellent corrosion resistance is widely used for a joint portion of a pipe through which a corrosive fluid flows. As a PTFE sealing material that can improve the adhesion to the tightening surface with a not so strong tightening force, a sealing material using expanded porous polytetrafluoroethylene (hereinafter abbreviated as “ePTFE”) has been attracting attention. . For example, Japanese Utility Model Laid-Open No. 3-89133 discloses an ePTFE annular sealing material obtained by punching an ePTFE film laminated body in which ePTFE films are laminated and integrated to a predetermined thickness into an annular shape.

Further, in order to improve the airtightness between the intake hole of the fan cover of the electric blower and the fan to prevent the generation of a circulating flow, the coefficient of friction is low, and thermal deformation occurs even when operating in a light sliding state. An annular sealing material made of ePTFE is used because such problems do not occur (Japanese Patent Laid-Open No. 07-18999).
No. 2). The ePTFE annular sealing material disclosed in this publication is formed by punching out an ePTFE resin sheet material in an annular shape.

The method for manufacturing the ePTFE sealing material disclosed in the above publication, that is, the method shown in FIG. 17, is a method for punching a flat ePTFE sheet 100 into an annular shape to obtain an annular sealing material 101. . Flat plate e
The remaining portion 102 obtained by punching out the annular material 101 from the PTFE sheet 100 has no use and must be discarded, which is not economical.

In the case of a ring-shaped sealing material composed of a film laminated body, as shown in FIG. 18, an ePTFE film is wound and laminated on a mandrel 103 to produce a laminated cylindrical body 104. A method is conceivable in which 104 is cut at intervals of the axial length P corresponding to the thickness of the annular sealing material to directly produce the annular sealing material having the axial thickness P. However, in such a manufacturing method, it is necessary to prepare mandrels having various diameters according to the type of product, which is not economical. Further, when forming an ePTFE cylindrical body having various diameters by extrusion molding and stretching, it is necessary to prepare dies having various diameters, which is unsuitable for high-mix low-volume production.

On the other hand, in addition to the annular sealing material, tape-shaped sealing material is known. This is as shown in FIG.
It is obtained by cutting the flat ePTFE sheet 105 with a predetermined width Q. The tape-shaped sealing material 106 obtained in this manner is attached to the tightening surface after the user has made a ring shape by connecting the start end and the end of the tape-shaped sealing material 106 at the site of use (see FIG. 20). , Fan cover attached to the edge of the intake hole. In FIG. 20, 110 is a connecting portion between the start end and the end. The tape-shaped sealing material is economical because the entire flat plate-shaped ePTFE body 105 can be effectively used due to its manufacturing method. However, when connecting both ends of the tape-shaped sealing material, it is necessary to take care so that leakage does not occur at the connection portion 110.

As a method for connecting the tape-shaped sealing material, for example, the tape-shaped sealing material is cut to a length suitable for ring closure, and then adhered to the start end surface and the end surface of the tape-shaped sealing material to be joined surfaces. There is a method of joining both end surfaces by applying an agent or the like. In this method, the length error when cutting affects the size of the circumference of the annular sealing material that is finally formed, so it is necessary to accurately determine the cutting length.
Since the area of the joining portion is small, it is difficult to obtain sufficient adhesive force, and leakage easily occurs at the connecting portion.

As shown in FIG. 21, a tape-shaped sealing material 1
There is a method in which both end surfaces of 11 are obliquely cut so as to have a taper of an angle θ to form a parallelogram tape-shaped sealing material. FIG. 21 (b) shows a case where both ends of the tape-shaped sealing material 111 shown in FIG. 21 (a) are connected to form an annular shape, and such connection has an adhesive strength due to an increase in the area of the connecting portion. Since it is sufficiently elevated, the connecting portion 113
Is unlikely to leak.

However, in the field of use, the work of tapering both ends of the tape-shaped sealing material is very troublesome, and further, the both ends are not cut accurately in parallel and obliquely so that the tape-shaped sealing material becomes a parallelogram. Then, a gap is created at the joint where the tapered surfaces of the two are stuck together, which causes leakage.

As a connection method which reduces the burden on the site user, one end of the tape-shaped sealing material is tapered and the other end is mounted on the taper so that both ends are overlapped and the tightening pressure is applied in this state. There is a method in which both ends are joined and integrated by applying. This method does not require a precise work of making the taper angles equal and does not require sticking with an adhesive or the like, so that it is not a burden on the site user. However, at the joining part, the thickness increases by the thickness of the tape-shaped sealing material that has been overlapped, so when the tightening pressure is weak, it becomes difficult to make it completely flush with the parts other than the joining part. Leakage can occur at the interface with. Further, with the sealing material used for preventing the generation of the circulating flow in the electric blower, the fan slides on the surface of the sealing material, and thus it is difficult to adopt this connecting method which is difficult to be flush.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an annular seal material which is less burdensome to a user at a use site and which can effectively use materials without waste. To provide.

[0012]

The sealing material of the present invention comprises a band-shaped expanded porous polytetrafluoroethylene body, and a slit is cut in the longitudinal direction of the band-shaped expanded porous polytetrafluoroethylene body. Then, the slit is cut so that it can be deformed into a window frame shape by expanding in the width direction of the band-shaped stretched porous polytetrafluoroethylene body.

It is preferable that the cut length of the slit is set so that the end faces in the longitudinal direction, which are valley-folded when expanded in a window frame shape, can be substantially joined.

The longitudinal end face may be formed in a V shape, and one end face of the longitudinal end face that is valley-folded is provided with an engaging concave portion and the other end face is provided with an engaging convex portion. Good. Further, both end surfaces in the longitudinal direction may be formed in parallel and obliquely.

At least two or more V-shaped grooves are formed in the middle of the slit so as to face each other, and when the slit is widened, adjacent groove surfaces of the V-shaped groove are joined to form a polygonal shape. The inner corner of the window frame may be formed.

A radius may be provided at an end of the slit.

The length (L) in the longitudinal direction of the band-shaped stretched porous polytetrafluoroethylene body (band-shaped ePTFE body).
Is preferably 2 to 300 times the width direction length (W), and the length (A) between the slit end and the longitudinal end face is 0.001 times the width direction length (W). It is preferably 0.5 times. Further, the tear strength at the slit measured according to JIS K7128 is 1
It is preferably 00N or more.

Further, the sealing material of the present invention is the above-mentioned strip-shaped eP.
The TFE body is a laminated body formed by laminating ePTFE films, the ePTFE film is laminated so that the slits are cut in each of the films, and a permeation preventive layer is provided between the laminated bodies in the laminating direction. It may be a mode in which it is provided in parallel with the film.

In the sealing material of the present invention, an adhesive layer may be laminated on the ePTFE body. Specifically, a mode in which an adhesive layer is formed on both sides of the slit on at least one surface of the surface where the slit is cut in the belt-shaped ePTFE body; the belt-shaped stretched porous polytetrafluoroethylene body There is a mode in which adhesive layers are formed on both sides of the outer side surface parallel to the slit cutting direction.

Further, the sealing material of the present invention may be a sealing material with a support body in which a window frame-like body formed by expanding a slit is provided on the support body.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a sealing material according to an embodiment of the present invention. The sealing material 1 is a strip-shaped expanded porous polytetrafluoroethylene (ePTFE) body 2 having a width W, a thickness D and a length L, in which a slit 3 is cut in the longitudinal direction. Slit 3 is ePTF
It is cut so that it can be transformed into a window frame shape by expanding the E body 2 in the width direction.

Here, ePTFE as the material of the sealing material
Is, for example, as disclosed in Japanese Patent Publication No. 51-18991, polytetrafluoroethylene (PTF).
Obtained by removing the molding aid from the molded body of the paste obtained by mixing the fine powder of E) with the molding aid, stretching it at a high temperature and high speed to make it porous, and then firing it if necessary. In the case of uniaxial stretching, the nodes (folded crystals) are in the shape of thin islands at right angles to the stretching direction, and fibrils (folded crystals are unraveled by the stretching and drawn out so as to connect these nodes. Linear molecular bundles) are oriented in the stretching direction. The space between the fibrils or the space defined by the fibrils and the nodes has a fibrous structure with holes. Also,
In the case of biaxial stretching, the fibrils spread out radially, the nodes connecting the fibrils are scattered in islands, and there are many spaces defined by fibrils and nodes, forming a spider web-like fibrous structure. .

The sealing material of the present invention is flexible due to the porous structure of the ePTFE body 2 constituting the sealing material.
Therefore, the strip-shaped sealing material 1 is applied in the width direction (the arrow direction in FIG. 1).
The slit 3 can be widened in a window frame shape by pulling the slit 3 toward.

FIG. 2A shows a state in which the slit 3 of the sealing material shown in FIG. 1 is widened in the width direction. Slit 3
Is expanded to form a space 4 in the central portion of the seal material 1, and the end faces in the longitudinal direction are valley-folded. Figure 2
2B shows a state in which the slits 3 are further widened and the longitudinal end faces to be valley-folded are joined to each other as compared with the state shown in FIG. 2A. The state shown in FIG. 2B is a state in which the band-shaped sealing material 1 is deformed into an annular shape (this state is referred to as "annular sealing material 1 '" to distinguish it from the band-shaped sealing material 1). Space 4 formed by expansion of slit 3
Is circular. In FIG. 2, reference numeral 5 denotes a joint where the end faces in the longitudinal direction are joined, and the length of the joint 5 is approximately w.
/ 2.

The ePTFE body 2 has a length L, a width W, and a thickness D.
1 may be an integrally molded product, or may be a film laminate in which ePTFE films are laminated by a thickness D.

The average pore diameter of the ePTFE body 2 constituting the sealing material can be appropriately set depending on the stretching ratio of the ePTFE body 2 (each ePTFE film in the case of a film laminate), but is preferably 0.05 to 5.0 microns. , Especially 0.5
~ 1.0 micron is preferred. If the pores are too large, the number of communication holes will increase, leading to a decrease in sealing performance. On the other hand, if the average pore size is less than 0.05 micron, it is difficult to produce an ePTFE body.

The porosity of the ePTFE body 2 can be appropriately set within the range of 10 to 95% according to the draw ratio, but is 30 to
Within the range of 85%, it is preferable to select it according to the usage conditions (surface roughness of the tightening member, tightening force, etc.) of the sealing material, the usage site, and the like. It becomes softer as the porosity increases, making it easier to deform the slit 3 into a window frame shape, and exhibiting sealing properties even on rough surfaces with a small tightening force, but the strength as a sealing material decreases. In addition, the permeation leakage increases.

When the ePTFE body 2 is a laminate of ePTFE films, the thickness of the ePTFE film used is 2
The thickness is preferably 0 μm or more, more preferably 50 μm or more, and the upper limit is preferably 500 μm or less, more preferably 150 μm or less. This is because if the thickness exceeds 500 μm, it is not suitable for lamination, and if it is less than 20 μm, the film is difficult to handle.

When the ePTFE body 2 is a film laminate,
A temperature equal to or higher than the melting point of polytetrafluoroethylene, specifically 327 ° C., particularly 350 ° C. or higher, and 380 ° C.
It is particularly preferable to bake at 365 ° C. or lower. The ePTFE films laminated by firing adhere to each other and are integrated to such an extent that the overlapping portions are hardly visible. On the other hand, when fired at a temperature above 380 ° C, PTF
Due to the heat deterioration of the E resin, holes are formed in the ePTFE film laminate.

The length L in the longitudinal direction of the band-shaped sealing material 1 made of such an ePTFE body 2 is the length of the side on the slit forming surface side in the cross section in the direction orthogonal to the longitudinal direction (the length in the width direction of the band-shaped sealing material 1). 2) W is preferably 2 times or more, more preferably 5 times or more, and the upper limit thereof is preferably 300 times, more preferably 100 times or less. Two
If the length is less than twice, the width W in the width direction is large for the length L in the longitudinal direction of the band-shaped seal material 1, so that the annular seal material 1 '
Is difficult to form. That is, in the state of being deformed into the annular sealing material 1 ′, the difference between the outer circumference and the inner circumference increases as W / 2 corresponding to the length of the joint portion 5 increases. In order to form such an annular sealing material 1'by deformation, the cut length of the slit 3 must be shortened, and the space formed by the expansion of the slit 3 becomes too small. On the other hand, when it exceeds 300 times, the width W becomes too small due to the length L, and it is difficult to form the slit 3, or the radial thickness of the annular seal material obtained by deforming into a window frame shape. (When the ring is circular, it corresponds to the difference between the radius of the outer circumference circle and the radius of the inner circumference circle) and becomes too small, so that the fluid or the like flowing in the ring inner space 4 of the ring seal material 1 ' This is because it is weak against the force applied in the radial direction, and fluid leakage easily occurs.

The width W of the band-shaped sealing material 1 prevents leakage of the fluid flowing in the inner space 4 of the annular sealing material 1'in the state of the annular sealing material 1'formed by expanding the slit into a window frame shape. It is appropriately determined according to the radial length of the sealing material. Further, the thickness D of the band-shaped sealing material 1 is appropriately determined according to the axial length of the annular sealing material 1'corresponding to the thickness that can be tightened by the tightening surface.

The slit 3 of the band-shaped sealing material 1 is made of ePTF.
It is formed by punching the E body 2 with a Thomson die or cutting it with a plotter cutter, a water jet cutter, or the like. The width of the slit 3 is appropriately determined depending on the type of cutter used to form the slit 3, the porosity of the ePTFE body 2, and the like.

The length A between the end of the slit 3 and the end face in the longitudinal direction is a length required to deform the slit 3 into a window frame shape. Specifically, the width W of the band-shaped sealing material 1 is preferably 0.001 times or more, and more preferably 0.001 times or more.
It is more than 5 times. If it is less than 0.001 times, the length A between the slit end and the end face in the longitudinal direction becomes too small, and the slit 3
This is because the strength of the portion serving as a fulcrum when expanding the window frame shape becomes weak. On the other hand, the length A between the slit end and the end face in the longitudinal direction
Is preferably 0.5 times or less of the width W, more preferably 0.
It is less than 1 time. This is because if it exceeds 0.5 times, A becomes too large and it becomes difficult to spread it into a window frame shape, and it is difficult to join the end faces in the longitudinal direction that are valley-folded when spreading.

Here, when the slit 3 is expanded with the slit end as a fulcrum, the tear strength in the slit 3 measured according to JIS K7128 is preferably 100 N or more, and more preferably 150 N or more. When it is less than 100 N, when the slit 3 is widened,
There is a risk of breaking at the end of the slit 3, and when the sealing material is pulled in contact with the tightening surface in the state of being spread out like a window frame, the end of the slit 3 is If it does not have sufficient tear strength,
This is because the slit 3 will break at the end thereof.

The tear strength is not limited to the length A between the slit end and the end face in the longitudinal direction, but mainly the ePTF.
It depends on the material of the E body (porosity, pore diameter, stretching conditions, etc.). Since the ePTFE body used in the present invention is flexible and has excellent strength, it may satisfy the above tear strength even if the length A between the slit end and the longitudinal end face is small. it can.

In the sealing material having the above-mentioned structure, the slit end may have a radius 3a as shown in FIG. By providing the radius 3a at the end of the slit 3, the operation of expanding the slit 3 becomes easy, and the stress concentration on the end of the slit can be dispersed.

The band-shaped sealing material 1 shown in FIG. 1 has a rectangular upper surface (slit forming surface), but the band-shaped sealing material of the present invention is not limited to this. Figure 4
As shown in, the longitudinal end face may be obliquely cut at an angle α so that the slit forming surface has a parallelogram shape. That is, in the band-shaped sealing material 11, both longitudinal end surfaces have an angle α.
Are formed in parallel and diagonally.

The sealing material of the present invention, like the sealing material 1 shown in FIG. 1 or the sealing material 11 shown in FIG.
The longitudinal end face does not have to be a single face. Further, for example, as shown in FIG. 5, the end face in the longitudinal direction may be formed in a V shape having a valley portion v toward the slit 3 of the band-shaped sealing material 21. The V-shape is valley-folded so as to form a V-shape having a narrower angle with the valley portion v as a fulcrum, and therefore, in the case of the first usage mode described below, the substantial joining of the end faces becomes more reliable. Because.

Further, as shown in FIG. 6A, the engaging concave portion 22 may be provided on one surface of the end face in the longitudinal direction which is valley-folded, and the engaging convex portion 23 may be provided on the other surface. The longitudinal end surface provided with the engaging concave portion 22 and the engaging convex portion 23 is shown in FIG. 6B in a state where the slit 3 is widened to form a window frame shape.
As shown in FIG. 3, the engaging concave portion 22 and the engaging convex portion 2 are formed by valley folding.
3 engage to form an engagement joint 25. The engagement joint portion 25 has a higher joint strength than the joint portion 5 in which the longitudinal end faces are substantially joined by valley folds, and the action of the widened slit 3 trying to return to the closed state can be prevented. Therefore, the expanded window frame shape is stable.

In the case of forming the engaging concave portion and the engaging convex portion, the shape of the engaging portion is a trapezoidal convex portion (concave portion) in the case of FIG. Is not limited to this. Various shapes such as a circular shape (FIG. 7) and a square shape can be adopted.

The sealing material having the above-mentioned structure is manufactured by cutting a rectangular rod-shaped, flat-plate-shaped or tape-shaped ePTFE molded product into a predetermined size (length L, width W, thickness D). Good. When the ePTFE body is a film laminate, a flat or cylindrical ePTFE film laminate is produced and obtained by cutting the laminate into a predetermined size (length L, width W, thickness D). Good. Also, a rectangular flat plate ePTFE body is cut to form a strip ePTF.
In order to obtain the E-shaped body, following the conventional method for manufacturing a tape-shaped sealing material, a method of cutting from the end in parallel with one side of the flat-plate shaped ePTFE body (see FIG. 19) and a flat-shaped ePTFE body as shown in FIG. The sheet may be cut diagonally at an angle α. When cut at an angle α, it is possible to manufacture the strip-shaped sealing material 11 in which both end surfaces in the longitudinal direction are formed in parallel and obliquely as shown in FIG.

The band-shaped sealing material having the above-mentioned structure is used in the field of use as follows.

The first method of use is, for example, in the case of the strip-shaped sealing material 1 shown in FIG.
(FIG. 2 (a)), and when the slit 3 is further expanded in a window frame shape, the end faces in the longitudinal direction that are valley-folded are substantially joined to each other to be transformed into the annular sealing material 1 ′ (FIG. 2). (B)) is used. The ring-shaped sealing material 1'formed by expanding the slit 3 is used as a gasket of a flow path joint portion in which the ring inner space 4 formed by the expansion of the slit 3 serves as a fluid passage, or a fan and a casing in an electric blower. It can be used as a seal member provided at the edge of the intake hole of the fan casing in order to prevent a circulating flow from being generated in the gap.

The second method of use is based on the first mode of use, for example, the inner circumference of an annular seal material 1 '(FIG. 9 (a)) obtained by expanding the slit of the band-shaped seal material 1 into a circular shape and deforming it into an annular shape. This is a method of using it in a state of being twisted 180 degrees in the direction of the arrow so that the surface becomes the outer peripheral surface. In the sealing material 1 ″ twisted by 180 degrees, as shown in FIG. 9B, the joint portion 5 of the end face in the longitudinal direction of the strip-shaped sealing material 1 comes to be located on the inner peripheral side. Outer peripheral surface, that is, slit 3
The outer peripheral surface of the annular seal material 1 ′ obtained by simply expanding the ring forms the inner peripheral surface of the annular seal material 1 ″. In the first usage mode, the annular seal material formed by expanding the slit 3 In 1 ', there is a case where the force that the widened slit 3 tries to return to the original works, and when the widened slit 3 is widened, even if the longitudinal end faces are substantially joined to each other, they may tend to separate from each other. In the annular seal material 1 ″ in the aspect,
Double the length L of the strip-shaped sealing material 1'in the longitudinal direction (2 x L)
Is longer than the perimeter of the inside of the slit (corresponding to twice the slit cut length) by 2 × A, so that the force to match the shorter inner perimeter presses the longitudinal end faces at the joint 5. It becomes a force, and the restoring force for separating and returning the joint portion 5 does not work. That is, the state of the annular seal material 1 ″ formed by the deformation becomes stable.

The third method of use is to use the slit by expanding it into a window frame shape and then twisting it 90 degrees. For example, the band-shaped sealing material 11 shown in FIG. 4 is deformed into an annular shape based on the first mode of use (FIG. 10 (a)), and twisted 90 degrees in the direction of arrow p or the direction of arrow q. FIG. 10 (b) shows a case in which it is twisted by 90 degrees in the direction of arrow p, and the inner peripheral surface 11'a of the annular sealing material 11 'in the first usage mode is shown.
The upper surface 1 of the annular seal material 11 "'in a state in which is twisted by 90 degrees
1 "'b, and the outer peripheral surface 11'c of the annular sealing material 11' of the first usage mode is the bottom surface 1 in a state of being twisted by 90 degrees.
In the case of a gasket, it comes into contact with the tightening surface. When twisted in the direction of arrow q, the outer peripheral surface 11'c of the annular seal material 11 'in the first usage mode is Ring seal material 1 with 90 degrees twisted
It becomes the bottom surface 11 "'b of 1""and is deformed so as to contact the tightening surface.

The use of the third mode as described above is particularly effective in the case of the band-shaped sealing material 11 in which the end faces of the ePTFE body are formed in parallel and obliquely as shown in FIG. Figure 10
As shown in (b), in the band-shaped sealing material 11, the joint portion 15 has a bottom surface 11 of the annular sealing material 11 ″ ′ when twisted by 90 degrees from the inner peripheral surface side (twisted in the direction of arrow p). "'D. When the bottom surface 11 "'d of the annular sealing material 11"' is brought into contact with the tightening surface and tightened, the joint portion 15 is pressed, and the integration at the joint portion 15 is improved. This leads to improvement in sealing performance.

As described above, the band-shaped sealing material of the present invention is
The user can open the slit at the site of use and form the annular sealing material by simply joining the end faces in the longitudinal direction to each other, so that the user can precisely connect the longitudinal end to the site user like the conventional tape-shaped sealing material. Easy to use without requiring any work. Further, when the end faces in the longitudinal direction are substantially joined and deformed into an annular shape, the joined portion can be integrated by pressing or the like, so that the same sealing performance as that directly produced as the annular sealing material can be exhibited. Moreover, in manufacturing, as in the case of the tape-shaped sealing material, a flat sheet, a large-sized strip-shaped body can be cut to an appropriate size, and can be manufactured simply by cutting a slit. Unlike production, it is not necessary to prepare core materials corresponding to various sizes, which is advantageous in production management.

Next, another embodiment of the sealing material of the present invention will be described.

In the sealing material of the above embodiment, the window frame shape formed by expanding the slit has a substantially circular shape, but the present invention is not limited to this and may have a polygonal shape. For example, FIG. 11 shows an example of a band-shaped sealing material when forming a rectangular window frame. This band-shaped sealing material 31 is e
Diamond-shaped spaces 34, 34 having V-shaped grooves facing each other are formed in the middle of the slit 33 formed in the PTFE body 32. The diamond-shaped spaces 34 are formed at two locations in the middle of the slit 33 and at positions substantially equidistant from the longitudinal end of the ePTFE body 32. When the slit 33 of the sealing material 31 is widened in the arrow direction and the longitudinal end faces to be valley-folded are joined together, the joined longitudinal end faces are located on the outer peripheral side of the window frame, as shown in FIG. 11B. The joint portion 35 is formed, and the groove surfaces (34a, 34a) adjacent to the V-shaped groove are formed.
b) is joined to form a corner portion 36 on the inner peripheral side of the window frame. When two rhombic spaces 34, 34 are formed in the middle of the slit 33 as shown in FIG.
As shown in (b), it is spread in a rectangular window frame shape.
By adjusting the number of rhombic spaces formed in the middle of the slit 33, it is possible to form a polygonal annular sealing material having a pentagonal shape or more.

Next, the permeation preventive layer will be described.

When the ePTFE body is formed of a laminate of ePTFE films, a permeation preventive layer made of a material having no pores through which a fluid permeates may be interposed in the laminating direction. .

FIG. 12 (a) shows a flat ePTFE sheet 40 in which a permeation preventive layer 40a is provided approximately in the middle of the laminating direction when laminating the ePTFE film by a thickness D. This flat plate-shaped ePTFE sheet 40
Is cut to a length L and a width W, and the slit 43 is cut into the band-shaped sealing material 41 with the permeation preventive layer 40a interposed. FIG. 12B shows an annular seal material 41 ′ formed by expanding the slit 43 of the band-shaped seal material 41 and deforming it into an annular shape, and FIG.
12 shows a state in which the annularly deformed sealing material shown in FIG. 12B is further twisted by 90 degrees in the arrow direction, that is, the annular sealing material 41 ″ ′ according to the third usage pattern described above. In the twisted state, the ePTFE film is laminated in the radial direction, and the penetration preventing layer 4
0a is in a state of being interposed between the inner peripheral surface and the outer peripheral surface of the annular seal material 41 ″ ′. In this way, the ePTFE films to be laminated are laminated so that slits are cut in each. The ePTFE film laminated body having the above-mentioned structure, and the sealing material in which the permeation preventive layer is provided substantially in the middle of the laminating direction of the film is effective particularly in the third usage mode in which the film is twisted by 90 degrees.

That is, in the third usage mode, FIG.
Since it is used in the state shown in (c), the permeation preventive layer 40a is provided in the direction orthogonal to the leak direction of the fluid passing through the inside of the ring of the annular sealing material 41 ″ ′. This is because the essential role of the permeation preventive layer 40a that prevents the fluid that has passed through the ePTFE film on the inner peripheral side of the annular seal material 41 ″ ′ from penetrating to the outer periphery of the annular seal material 41 ″ ′ can be sufficiently exerted. is there.

As the constituent material of the permeation preventive material layer 40a,
In order to prevent fluid from penetrating, for example, non-porous PTFE (hereinafter referred to as “dense PTFE”), P
Examples of the resin other than TFE (hot melt type resin, thermosetting resin), rubber such as silicone rubber, metal, and the like, the usage environment of the sealing material (particularly, the type of fluid flowing through the pipe), the manufacturing method of the sealing material ( In particular, it can be appropriately selected depending on the presence or absence of firing, the characteristics to be imparted, and the like. For example, when sealing a corrosive fluid, a dense P with excellent corrosion resistance
It is preferable to use a TFE band-shaped film, and in the case of a high-pressure fluid, a metal band-shaped film (metal foil) may be used. Here, as the dense PTFE strip-shaped film,
Strip-shaped film composed of sintered PTFE, ePTFE film After stacking multiple strip-shaped films, ePTF
For example, a band-shaped film formed by crushing the holes of E may be used. The band-shaped film made of dense PTFE produced by crushing the pores of ePTFE has elasticity more than the band-shaped film made of sintered PTFE because the pores are crushed while maintaining the fiber orientation of ePTFE. Since it has excellent strength, it is suitable as a constituent material of the fluid permeation preventive material layer which requires corrosion resistance. The thickness of the fluid permeation preventive material layer depends on the type of constituent material of the fluid permeation preventive material layer, but is 5
μm, especially above 20 μm, 500 μm, especially 200 μm
m or less is preferable.

Since the sealing material having such a fluid permeation preventive layer interposed therebetween can achieve a higher degree of fluid leakage prevention as compared with a sealing material composed of an ePTFE body alone, a high sealing property is required. It is suitable for use in the field of gaskets.

Incidentally, ePTFE having a fluid permeation preventive layer interposed
When using the sealing material composed of a film laminate in the first aspect or the second aspect (when used in a state where the slit is widened or in a state where the slit inner surface is twisted 180 degrees so that the inner surface of the slit constitutes the outer peripheral surface) ), The permeation-preventing layer prevents the fluid that has passed through the ePTFE film on the inner peripheral side of the annular sealing material from penetrating to the ePTFE film on the outer peripheral side. It is necessary that the permeation-preventing layer is interposed in parallel with the slit, and it is preferable that the permeation-preventing layer is interposed on both sides of the slit. That is, it is necessary that the permeation preventive layer is interposed between two layers in the laminate.

Although the above-mentioned sealing materials of the present invention are each made of a strip-shaped ePTFE body alone, an adhesive layer may be laminated on a portion contacting the mounting surface of the ePTFE body.

For example, FIG. 13 shows a strip-shaped ePTFE body 52.
The surface on which the slit 53 is formed (slit forming surface)
An adhesive layer 54 is formed on both sides of the slit 53, and a sealing material 51 in which the adhesive layer 54 is covered with a release paper 55 is shown. Such a sealing material 51 has an adhesive layer 54.
The workability is good because the slits 53 can be widened while forming a window frame that follows the shape of the portion to be sealed on the fastening surface of the pipe connection portion or the mounting surface of the fan casing edge, etc.

Further, in the sealing material of the type in which the adhesive layer 54 is formed on both sides of the slit forming surface as described above,
After the slit 53 is widened to form a window frame shape, the slit 53 may be twisted 180 degrees and then contacted with the mounting surface in this state.

In FIG. 13, the adhesive layer 54 was laminated only on one side surface of the slit forming surface (the upper surface of the strip-shaped ePTFE body 52 in FIG. 13), but both the slit forming surfaces, that is, the strip-shaped ePTFE body 52. An adhesive layer may be laminated on the upper surface and the lower surface.

On the other hand, the sealing material 61 shown in FIG. 14 has an adhesive layer formed so that it can be applied to the third mode of use. The sealing material 61 has an adhesive layer 64 formed on the outer surface (side surface of the band-shaped sealing material) parallel to the slit cut direction, and the release paper 65 covers the adhesive layer 64. Such a sealing material 61 expands the slit 63 to form a window frame shape, and the inside of the slit 63 is the upper surface of the finally formed annular sealing material,
Adhesive layer 64 laminated on the side surface of the band-shaped ePTFE body 62
Abut the mounting surface. In this way, by fixing the adhesive layer 64 to the mounting surface,
Since it can be prevented from returning when twisted, it can be easily mounted on the mounting surface.

As the adhesive constituting the adhesive layer 54 (64), conventionally known adhesives such as acrylic adhesives and rubber adhesives can be appropriately used, but acrylic adhesives are preferable because they have excellent heat resistance. As the adhesive, a liquid adhesive may be applied, or a sheet-like adhesive may be stuck and used.

The thickness of the adhesive layer 54 (64) is 3 to 200.
μm is preferable, and 5 to 25 μm is particularly preferable. Thickness is 3
If it is less than μm, the tackiness becomes insufficient, and if it exceeds 200 μm, the influence of the heat resistance and chemical resistance of the adhesive on the sealing material cannot be ignored and the sealing performance is deteriorated. In addition, the width of the adhesive layer 54 (64) may be a width corresponding to the entire contacting portion of the sealing material by applying an adhesive to the entire contacting surface, or the contacting surface. The width may be narrower than the contact portion of the seal material by applying the adhesive agent to only a part of the.

The adhesive layer 54 (64) is a strip-shaped ePTFE.
After forming the body, it may be formed by applying an adhesive to the corresponding portion, or may be formed into a flat plate or a large-sized strip e.
The adhesive may be applied to the entire slit forming surface of the PTFE body and then cut into a predetermined size to form a band-shaped sealing material with an adhesive layer.

The outer surface of the adhesive layer is usually covered with a release paper so that the adhesive performance can be maintained until just before use. However, when the adhesive performance can be maintained, the release paper can be maintained. It does not have to be.

As the release paper, any sheet-like material having releasability can be used as appropriate, but paper coated or impregnated with a release agent such as silicone resin or fluorine resin, polyethylene film or polypropylene film A resin film having excellent releasability such as, a polyester film or a polyimide film having a surface coated with a release agent such as a silicone resin or a fluorine resin is preferably used.

The use mode of the sealing material of the present invention is not limited to the case where the user expands the slit at the use site to form the annular sealing material. As shown in FIG.
It is also possible to supply it to the user in a state in which a window frame-like body formed by expanding the slit is provided (a sealing material with a support). As a method for fixing the window frame-shaped body 71 on the support body 72, various methods such as pressing and adhesive can be applied.

Here, the window frame-like body 71 corresponds to the above-mentioned annular seal material of the present invention, and is 180 degrees or 9 degrees in addition to the annular seal material (first usage mode) formed by simply expanding the slit.
An annular seal material (second or third usage mode) obtained by twisting at 0 degrees can be provided on the support.

The sealant with a support forms an annular shape on the producer side, but since the annular sealant is formed from the strip-shaped sealing material of the present invention, it is possible to produce an annular sealant of various sizes.
It is not necessary to prepare a core material having a diameter corresponding to each size of the annular sealing material, which is convenient in terms of production equipment and production management.

When the producer side deforms into an annular shape and supplies it to the user, the deformed annular seal material may be used alone without being attached to the support body 72. When the support body is provided, the annular seal material may be used. The shape does not have to be annular as long as it can support the material.

[0071]

EXAMPLES The present invention will be described below based on specific examples. [Measurement of Leakage Amount] The sealing properties of the annular sealing materials produced in the following Examples and Comparative Examples were measured as follows.

As shown in FIG. 16A, a bottomed cylindrical body 82
The prepared annular sealing material 81 was set in the upper opening of the above, and the upper opening was covered with the lid 83.

With the lid on (FIG. 16 (b)), the tightening pressure is gradually increased to a predetermined pressure, and then compressed air is blown into the container 82 so that the internal pressure is 0.1 MPa and the surface pressure is approximately equal. Leakage amount at 1 MPa (Pa · m ³ / s
ec) was measured. Here, the tightening pressure is adjusted by the lid 83.
It was carried out by the load applied to. The load was calculated by "area of sealing material x tightening pressure". For example, when a tightening pressure of 10 MPa was applied to a seal material having an inner diameter of 34 mm and an outer diameter of 42 mm, a load of 4770 N was applied. The leak amount is P ×, where the internal pressure of the container 82 after T seconds from the closing of the cock is read with a gauge and the decrease in the internal pressure is P (unit: MPa).
It is calculated by 50 / T (unit: Pa · m ³ / sec).
Here, 50 in the formula is the volume (cm ³ ) of the portion that encloses the air.

[Manufacture of Sealing Material] (1) Example 1 A commercially available rectangular ePTFE sheet having a thickness of 2 mm and a side of 1500 mm (a hyper sheet manufactured by Japan GORE-TEX Co., Ltd.) is cut parallel to one side of the sheet. At the same time, by cutting a slit parallel to the side, the length L in the longitudinal direction is 60 mm, the width W is 8 mm, the slit length is 58 mm, and the length A between the longitudinal end face and the slit end is A.
A band-shaped sealing material 1 shown in FIG. Above eP
About 4500 strip-shaped sealing materials 1 could be manufactured from the TFE flat plate.

A double-sided adhesive tape having a width of 2 mm (# 9458 manufactured by Sumitomo 3M) was attached to both sides of the slit on one slit forming surface of the obtained band-shaped sealing material.

Spread the slit of the band-shaped sealing material into a window frame shape,
While peeling off the release paper of the double-sided adhesive tape and applying the adhesive to the upper opening of the cylindrical body 82 of the evaluation device, the longitudinal end faces to be valley-folded are substantially joined, and the inner diameter is 34 mm, the outer diameter is 42 mm, and the axis is An annular sealing material having a thickness of 2 mm in the direction was formed.

(2) Example 2 A commercially available rectangular ePTFE sheet having a thickness of 4 mm and a side of 1500 mm (Hypersheet manufactured by Japan GORE-TEX Co., Ltd.) was diagonally cut at an angle α = 20 ° and cut along a cutting line. By cutting the slits in parallel,
A parallelogram band-shaped sealing material 11 having a longitudinal length L of 60 mm and a width W of 4 mm was obtained. Slit notch length 58
mm, the length A between the longitudinal end face and the slit end is 1
mm. Such a band-shaped sealing material is the flat plate-shaped e
About 9000 pieces could be produced from the PTFE sheet.

A width of 2 m is provided on both sides of the obtained band-shaped sealing material.
m double-sided adhesive tape (Sumitomo 3M # 945
8) was attached.

Spread the slit of the band-shaped sealing material into a window frame shape,
After the longitudinal end faces to be valley-folded are substantially joined and deformed into an annular shape, 90
Twisted by 34 mm inner diameter, 42 mm outer diameter, axial thickness 2
The release paper of the double-sided pressure-sensitive adhesive tape was peeled off and the pressure-sensitive adhesive was attached to the upper opening of the cylindrical body 82 of the evaluation device while forming the circular ring-shaped sealing material of mm shown in FIG.

(3) Comparative Example 1 From the ePTFE sheet (thickness 2 mm, one side 1500 mm hypersheet manufactured by Japan GORE-TEX Co., Ltd.) used in Example 1, punched into a ring shape having an inner diameter of 34 mm and an outer diameter of 42 mm, an inner diameter of 34 mm, An annular seal material having an outer diameter of 42 mm and an axial thickness of 2 mm was obtained. From the flat plate, 11
Only about 00 annular sealing materials were obtained.

A width of 2 m is provided on the bottom surface of the obtained annular seal material.
m double-sided adhesive tape (Sumitomo 3M # 9458)
Was peeled off, the release paper of the double-sided pressure-sensitive adhesive tape was peeled off, and the pressure-sensitive adhesive was stuck to the upper opening of the cylindrical body 82 of the evaluation device.

(4) Comparative Example 2 From the same ePTFE sheet as that used in Example 1,
Longitudinal length L is 120 mm, width W is 4 mm, thickness D2
mm tape-shaped sealing material with a rectangular top surface,
A double-sided adhesive tape having a width of 2 mm (Sumitomo 3M # 9458) was attached to the bottom surface.

Both ends of the tape-shaped sealing material are butt-joined to each other to form an inner diameter of 34 mm and an outer diameter of 42 mm as shown in FIG.
An annular seal material having a thickness of 2 mm in the axial direction was produced.

The release paper of the double-sided pressure-sensitive adhesive tape was peeled off, and the pressure-sensitive adhesive was attached to the upper opening of the cylindrical body 82 of the evaluation device.

(5) Comparative Example 3 From the same ePTFE sheet as that used in Example 1,
A tape-shaped sealing material having a length L in the longitudinal direction of 125 mm, a width W of 4 mm, and a thickness D of 2 mm was prepared, and both longitudinal end surfaces thereof were inclined at θ = 20 ° as shown in FIG. 21 (a). Disconnected. A double-sided adhesive tape having a width of 2 mm (Sumitomo 3M # 9458) was attached to the bottom surface of the tape-shaped sealing material.

By joining and joining the cut ends of this tape-shaped sealing material, the inside diameter 3 as shown in FIG.
An annular seal material having a diameter of 4 mm, an outer diameter of 42 mm and an axial thickness of 2 mm was produced.

The release paper of the double-sided pressure-sensitive adhesive tape was peeled off, and the pressure-sensitive adhesive was attached to the upper opening of the cylindrical body 82 of the evaluation device.

The amount of leak of each sealing material attached to the evaluation device cylindrical body 82 was measured as described above, and the results are shown in Table 1.

[0089]

[Table 1]

The annular sealing material of Comparative Example 2, which was formed by abutting and joining both ends of a simple tape-shaped sealing material, had a large drop pressure and was inferior in sealing property.

On the other hand, the sealing properties of the annular sealing materials (Examples 1 and 2) formed by deforming the band-shaped sealing material of the present invention are the same as those when the annular sealing material is directly formed (Comparative Example 1). Has a degree of sealing property.

Further, the ring-shaped sealing material (Example 2, Comparative Example 3) obtained by cutting the end face in the longitudinal direction obliquely to increase the area of the joint portion is more rectangular than the strip-shaped sealing material of Example 1 ( Or, the pressure drop was smaller than that of the tape-shaped sealing material of Comparative Example 2 and the sealing property was excellent.

[0093]

Since the sealing material of the present invention is a band-shaped sealing material, it can be produced without wasting expensive ePTFE at the production site. Also, the slit can be transformed into an annular sealing material by simply expanding it into a window frame or twisting it, and since it does not require the troublesome joining work as in the past, the burden on the user at the site of use is small, and Less variation due to user work ability. Further, the sealing material of the present invention can exhibit the same level of sealing performance as the conventional annular sealing material manufactured by punching, regardless of the user.

Therefore, it is advantageous for the producer in terms of production equipment, production management, and economically, and for the user,
The work load is light, and there is little variation in the sealing performance depending on the worker.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a band-shaped sealing material according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of using the band-shaped sealing material shown in FIG.

FIG. 3 is a diagram showing another embodiment of the band-shaped sealing material of the present invention.

FIG. 4 is a view showing another embodiment of the band-shaped sealing material of the present invention.

FIG. 5 is a view showing another embodiment of the band-shaped sealing material of the present invention.

FIG. 6 is a view showing a sealing material of the present invention in which an engaging joint portion is provided on an end face in the longitudinal direction.

FIG. 7 is a diagram showing another example of the engaging portion.

FIG. 8 is a diagram for explaining an example of the method for manufacturing the sealing material of the present invention.

FIG. 9 is a diagram for explaining a second usage pattern of the sealing material of the present invention.

FIG. 10 is a diagram for explaining a third usage pattern of the sealing material of the present invention.

FIG. 11 is a diagram showing the configuration and usage of another embodiment of the sealing material of the present invention.

FIG. 12 is a diagram showing the structure and usage of the sealing material of the present invention having a permeation preventive layer.

FIG. 13 is a diagram showing a configuration of a sealing material of the present invention having an adhesive layer.

FIG. 14 is a view showing another embodiment of the sealing material of the present invention having an adhesive layer.

FIG. 15 is a view showing an embodiment of a seal material with a support of the present invention.

FIG. 16 is a diagram for explaining the measuring method adopted in the example of the present invention.

FIG. 17 is a diagram for explaining a problem of a conventional annular seal material.

FIG. 18 is a diagram for explaining a conventional method for manufacturing an annular sealing material.

FIG. 19 is a diagram for explaining a conventional method for manufacturing a tape-shaped sealing material.

FIG. 20 is a diagram showing a configuration of an annular sealing material formed of a conventional tape-shaped sealing material.

FIG. 21 is a view showing another embodiment of the conventional tape-shaped sealing material.

[Explanation of symbols]

1,11,21,31,41 Band-shaped sealing material 1 ′ An annular sealing material according to the first usage mode 1 "Annular sealing material according to second usage mode 1 ″ ″ Annular sealing material according to third usage mode 2,52,62 ePTFE body 3,33,43,53 slit 3a are 5,15,35,55 Joint 22, 22 'engaging recess 23, 23 'engaging protrusion 36 corners 40a Permeation prevention layer 51,61 Band-shaped sealing material with adhesive layer 54, 64 adhesive layer 71 Window frame 72 Support

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16J 15/10 F16J 15/10 U F term (reference) 3J040 AA01 BA08 FA07 HA03 4F100 AK18A AK18B AR00C AT00D BA02 BA03 BA04 BA07 BA10A BA10D BA13 CB00 DC13A DC13B DJ06A DJ06B GB51 JD01C 4H017 AA04 AB12 AD01 AD04 AE02 AE03

Claims (14)

[Claims] 1. A band-shaped stretched porous polytetrafluoroethylene body, wherein a slit is cut in the longitudinal direction of the band-shaped stretched porous polytetrafluoroethylene body, and the slit is the band-shaped stretched porous body. Sealing material that is cut so that it can be transformed into a window frame shape by expanding it in the width direction of the polytetrafluoroethylene body. 2. The cut length of the slit is such that the longitudinal end faces that are valley-folded when expanded in a window frame shape are
The sealing material according to claim 1, which is set so as to be substantially joined. 3. The seal material according to claim 2, wherein the end face in the longitudinal direction is formed in a V shape. 4. The sealing material according to claim 2, wherein one end face of the longitudinal end face that is valley-folded is provided with an engagement concave portion, and the other end face is provided with an engagement convex portion. 5. At least 2 in the middle of the slit.
V-shaped grooves are formed facing each other at more than one place, and when the slits are widened, adjacent groove surfaces of the V-shaped grooves are joined to form a corner portion inside the window frame made of a polygon. The sealing material according to claim 2, wherein 6. The sealing material according to claim 2, wherein both end faces in the longitudinal direction are formed in parallel and obliquely. 7. The sealing material according to claim 1, wherein a radius is provided at an end of the slit. 8. The length (L) in the longitudinal direction of the band-shaped stretched porous polytetrafluoroethylene body is the length (W) in the width direction.
2 to 300 times the sealing material according to any one of claims 1 to 7. 9. The length (A) between the slit end and the longitudinal end face is 0.001 of the width direction length (W).
It is 0.5 times, The sealing material of Claims 1-8. 10. The sealing material according to claim 1, wherein the slit has a tear strength of 100 N or more measured according to JIS K7128. 11. The belt-shaped stretched porous polytetrafluoroethylene body is a laminate obtained by laminating stretched porous polytetrafluoroethylene films, wherein the stretched porous polytetrafluoroethylene film is formed on each of the films by The sealing material according to any one of claims 1 to 10, wherein the sealing material is laminated so that slits are cut, and a permeation preventive layer is provided in parallel with the film in a laminating direction of the laminated body. 12. The adhesive layer is formed on both sides of the slit in at least one surface of the surface in which the slit is cut in the strip-shaped stretched porous polytetrafluoroethylene body. Seal material described. 13. The sealing material according to claim 1, wherein an adhesive layer is formed on both outer surfaces of the band-shaped stretched porous polytetrafluoroethylene body which are parallel to the slit cutting direction. 14. A support-equipped sealing material comprising a support and a window frame-shaped body formed by expanding the slit of the sealing material according to claim 1.