JP2003148621A - Coating type seal material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating type seal material exhibiting excellent sealing performance even to a large size object or a largely corrugated surface without wasting a material. SOLUTION: As a core material, an ePTFE ring consisting of a strip ePTFE body is used. Concretely, examples thereof include a strip ePTFE body annularly formed by mutually connecting both the longitudinal end surfaces of the strip ePTFE body; an ePTFE ring formed by forming a slit in the longitudinal direction of a strip ePTFE body, and extending the slit in the lateral direction to annularly deform the body, or the one further folded after annularly deformed; a strip ePTFE body comprising two or more V-shaped cutout parts formed on the side edge of the strip ePTFE body, the opposed surfaces forming the V-groove of the cutout part being bonded to each other to form an inside surface; and such an ePTFE ring supported on a metallic ring-like flat plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention seals a flange portion of a pipe or a container, in particular, a surface contact portion of a tightening surface having a so-called waviness, which is highly uneven with a glass lining, and a flange portion of a large tank. The present invention relates to a coating type sealing material which is effective for

[0002]

2. Description of the Related Art Pharmaceuticals,
In the field of foods, chemicals, etc., as a covering type sealing material used for a joint part of a pipe through which a corrosive fluid flows, conventionally, asbestos felt, asbestos joint sheet, a material having a compressibility such as a rubber plate, or these A ring-shaped core material made of a material reinforced with a metal plate or the like is covered with a polytetrafluoroethylene (PTFE) outer covering material having excellent corrosion resistance.

However, in the sealing surface of the glass lining equipment, since the unevenness of the tightening surface, that is, the undulation, is large, the compression amount of asbestos felt or the like is far beyond the range that can be handled. A method called shim adjustment, that is, a gap is created due to the unevenness due to the waviness of the tightening surface, and the thickness of the sealing material is adjusted so as to fit into the unevenness of the tightening surface. However, such a method is not only troublesome in terms of work, but is not satisfactory in terms of sealing property. Even if the outer skin that contacts the fluid is made of PTFE, which has excellent corrosion resistance, the outer skin is formed as a thin film so that it can adapt to the tightening surface and be deformed. There is a problem that it penetrates the outer skin material at a level and attacks the asbestos felt, the rubber plate, and the core material made of metal, and that the core material itself is deteriorated by heat.

In order to solve such a problem, JP-A-4-331876 proposes to use porous polytetralofluoroethylene as a core material.

Since porous polytetralofluoroethylene can set a large amount of initial compression at the time of sealing, it can follow even a tightening surface with severe irregularities (waviness), and eventually exhibits excellent sealing performance. You can

The ring of porous PTFE used as the core material in the above publication is manufactured by punching a porous PTFE sheet into a ring shape.

When manufacturing a ring by punching,
As shown in FIG. 16, the remaining portion 102 where the ring-shaped material 101 is punched out from the ePTFE sheet 100 has to be discarded. However, since porous PTFE is expensive, if many parts are discarded, the cost of the sealing material will increase. In particular, when a large-sized sealing material is manufactured, the portion to be discarded becomes large, so that the problem of cost increase cannot be avoided. Also, there is a limit to the size of the ePTFE sheet that can be manufactured, and inevitably there is also a limit to the size of the ePTFE ring that is punched out from the sheet.
The maximum size of a ring made by punching from a commercially available ePTFE sheet available today has an outer diameter of about 1500 mm. On the other hand, at present, there are many glass lining containers having a diameter of 1500 mm or more, and the method by punching cannot provide an ePTFE ring applicable to these. Furthermore, when using a core material made of ePTFE as a core material for a large-sized sealing material, the material e
There is a problem that it is difficult to handle due to the flexibility of PTFE.

The present invention has been made in view of such circumstances, and an object of the present invention is to eliminate a waste of material and, even in a large size, with respect to a surface having a large unevenness (waviness). Is to provide a coating type sealing material that can exhibit excellent sealing performance.

[0009]

The coated type sealing material of the present invention is a stretched porous polytetrafluoroethylene ring (hereinafter referred to as "ePTFE") made of a band-shaped stretched porous polytetrafluoroethylene body (hereinafter referred to as "ePTFE body").
(Hereinafter referred to as "ring"), and a ring-shaped outer cover made of baked polytetrafluoroethylene that covers the outer surface of the core.

As the core material, the strip-shaped ePTFE is used.
An annular shape in which both longitudinal ends of the body are connected (first
(Embodiment); A slit is cut in the longitudinal direction in the strip-shaped ePTFE body, and the ePTFE ring is obtained by expanding the slit in the width direction and deforming into an annular shape, or the slit in the width direction. After being expanded and deformed into an annular shape, the strip-shaped ePTFE body is folded back into an annular shape so that the upper surface or the lower surface becomes the outer peripheral surface, or the slit is expanded in the width direction and deformed into an annular shape, and then inside the slit. An annular shape in which the side surface is folded back to be the outer peripheral surface (second embodiment); a plurality of V-shaped notches are formed at the side edge of the strip-shaped ePTFE body,
One in which the facing surfaces forming the V groove of the notch are joined to form an inner peripheral surface (third embodiment); two of the ePTFEs
A first eP including a ring and a metal ring-shaped flat plate
The TFE ring is supported on the upper surface of the flat plate, and the second eP
A TFE ring supported on the lower surface of the flat plate (4th
Embodiment) and the like.

EPTF of the first and second embodiments
The E-ring is preferably fixed to the annular outer skin material.

[0012] In the ePTFE ring of the third embodiment, it is preferable that the total length of the notch remaining portions at the side edges of the strip-shaped ePTFE body is equal to or greater than the inner peripheral length of the ePTFE ring.

The ePTFE body may be an integral body or a laminate of ePTFE films.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The coated type sealing material of the present invention is
In a coating-type sealing material that includes a ring-shaped core material and an annular outer covering material that covers the outer surface of the core material, a strip-shaped expanded porous polytetrafluoroethylene body (ePT) is used as the core material.
It is characterized by using an ePTFE ring composed of an FE body).

[First Embodiment] FIG. 1 is a view showing the arrangement of a coating type sealing material according to the first embodiment of the present invention.

In the coating type sealing material of the first embodiment,
As a core material, an ePTFE ring 1 (FIG. 2) in which both ends in the longitudinal direction of a band-shaped expanded porous polytetrafluoroethylene (ePTFE) body 3 shown in FIG.
(B)) is used. In FIG. 2 (b), reference numeral 1 a indicates a connecting portion of both end faces in the longitudinal direction of the band-shaped ePTFE body 3.

The ring-shaped outer cover material 2 covering the outer surface of the core ePTFE ring 1 is formed by folding a fired polytetrafluoroethylene sheet into two as shown in FIG. Half-folded half-folded sheets 4, 4
Are connected so that the folds 4a are on the inner peripheral side, whereby the annular outer covering material 2 can be formed (FIG. 2 (d)). Two
Sheet edge 4 on the side opposite to fold 4a of folded sheet 4
The ePTFE ring 1 as a core material can be inserted from the opening 4c of the space defined by b and 4b. Figures 1 and 2
Inside, 2b has shown the connection part of the folded sheet 4 comrades.

The method of inserting and mounting the ePTFE ring 1 into the annular outer cover material 2 is not particularly limited, but generally the following method is preferably used. First, the annular outer covering material 2 is prepared, and the strip-shaped ePTFE body 3 is attached to the outer covering material 2 so as to be along the fold 4a of the annular outer covering material 2. Then, by connecting both end faces in the longitudinal direction of the strip-shaped ePTFE body 3 to form an annular shape, as shown in FIG.
It is possible to obtain a coating type sealing material that covers the outer surface of the PTFE ring 1. When the strip-shaped ePTFE body 3 is attached to the annular skin material 2, it is preferable to fix the strip-shaped ePTFE body 3 to the annular skin material 2 using an adhesive or an adhesive tape. Further, it is preferable to use an adhesive or a pressure-sensitive adhesive tape also when connecting the end faces in the longitudinal direction of the band-shaped ePTFE body 3. This is because the ePTFE ring 1 can be easily formed. As the adhesive used for the adhesive or the adhesive tape, an acrylic adhesive, a rubber adhesive, or the like is used, and an acrylic adhesive having excellent heat resistance is preferably used.

The strip-shaped ePTF is made to be along the fold line 4a of the ring-shaped outer cover material 2 which is relatively hard and whose shape can be easily retained.
According to the method of forming the ePTFE ring 1 by mounting the E body 3 on the outer skin material 2, regardless of the size of the sealing material, only the band-shaped ePTFE body is handled, and it is difficult to maintain the shape of the large-sized ePTFE ring. Need not be dealt with directly. Therefore, the ePTFE material can be applied as the core material for the covering type sealing materials of various sizes.

EPTF used as a material for the band-shaped ePTFE body 3
E means polytetrafluoroethylene (PTF) as disclosed in, for example, Japanese Patent Publication No. 51-18991.
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 ePTFE body 3 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.

Band-shaped ePT constituting the ePTFE ring 1
The FE body 3 is not particularly limited in its average pore size and porosity, and a commercially available ePTFE body or ePTFE film laminate can be used.

As shown in FIG. 2A, the strip-shaped ePTFE body 3 is preferably cut so that both longitudinal ends thereof are oblique to the thickness direction by an angle θ and both ends are parallel to each other. Thereby, the connection between the starting end and the terminating end of the band-shaped ePTFE body 3 can be achieved only by overlapping the cut surfaces at both ends, and the annular shape can be easily formed. And the connecting portion 1a formed by superposition
2 is oblique in the axial direction of the ePTFE ring 1 as shown in FIG. Seal material is ePTFE ring 1
Since it is used so that the tightening force acts in the axial direction, it is possible to enhance the integration of the connecting portion 1a by overlapping. The connection portion 1a is highly integrated in the state of being sandwiched between the tightening surfaces, but in order to maintain the ring shape in the state of the sealant alone, the connection of both longitudinal end surfaces is performed with an adhesive or an adhesive tape. May be used.

In general, when there is a part made of an adhesive or a pressure sensitive adhesive in a part of the sealing material, the adhesive part (adhesive part)
May be invaded by chemicals or the like to break its part, resulting in fluid leakage. However, with the coated type sealing material of the present invention, when the sealing material is manufactured (for example, the strip-shaped ePTF
Even if an adhesive or a pressure-sensitive adhesive tape is used for the connecting portion on both end surfaces of the E body or the fixed portion between the annular outer skin material 2 and the ePTFE body), when attached to the tightening surface, it retains the ring shape and the annular outer skin material. Since the adhesiveness with 2 is sufficiently maintained and the integrity of the connecting portion 1a can be secured, the role of the adhesive or the adhesive tape is not important. Therefore, even if the fluid that has permeated the annular skin material 2 comes into contact with the adhesive portion (or the adhesive portion) and the adhesive portion deteriorates or breaks, the sealing performance is not affected.

The strip-shaped ePTFE body is obtained by cutting a rectangular rod-shaped, flat-plate-shaped, or tape-shaped ePTFE molded body into a predetermined size (length L, width W, thickness D), etc., and manufacturing a ring by punching. There are few parts that have to be discarded as in the case. Further, when a strip-shaped ePTFE body is obtained by cutting a rectangular flat-plate ePTFE body, a method of cutting from the end parallel to one side of the flat-plate ePTFE body in accordance with a conventional tape-shaped sealing material manufacturing method (see FIG. In addition to (a)), as shown in FIG. 3 (b), a flat plate-shaped ePTFE sheet is obliquely cut at an angle θ to directly manufacture the strip-shaped ePTFE body 3 shown in FIG. 2 (a). You may Further, when a long band-shaped ePTFE body that can be used for a large-diameter sealing material is required, as shown in FIG. 4, an ePTFE roll formed by winding an ePTFE film is cut into a spiral shape (one-dot chain line). Good. In either case, the ePTFE sheet can be effectively used because there are few parts to be discarded.
And since the whole core material is made of ePTFE body, it has excellent corrosion resistance, a large unevenness difference, that is, adhesion to a tightening surface with a large undulation, and a high sealing property, like an ePTFE ring manufactured by punching. Can be demonstrated.

As shown in FIG. 1, the ring-shaped outer cover material is not limited to the one formed by connecting the two folded sheets 4 of the fired PTFE sheet into a ring shape, and as shown in FIG. A PTFE sheet may be cut open along the outer peripheral surface.

[Second Embodiment] The covering type sealing material of the second embodiment is a strip-shaped strip-shaped e formed by cutting a slit in the longitudinal direction of a strip-shaped ePTFE body as a core material.
It is characterized in that a slit of a PTFE body is widened in the width direction and is deformed into an annular shape. As the annular skin material, the one used in the first embodiment can be used, and the method of attaching the ePTFE ring to the annular skin material can also be performed by the same method as in the first embodiment.

The core material used in the second embodiment will be described below.

FIG. 6 (a) shows a strip-shaped ePTFE body 13 with slits which is the material of the core material, and FIG. 6 (b) expands the slits 14 of the strip-shaped ePTFE body 13 with slits to transform it into a ring. FIG. 6C shows the ePTFE ring 13A obtained by the deformation (hereinafter, the ePTFE ring obtained by expanding the slit of the strip-shaped ePTFE body 13 with slits will be referred to as "A type ePTFE ring").
FE ring ").

The strip-shaped ePTFE body 13 with slits is made of the same ePTFE as the strip-shaped ePTFE body of the first embodiment, and may be an integral body or a film laminated body. In the case of a film laminate, the ePTFE film may be laminated in the width direction of the band-shaped body or may be laminated in the thickness direction.

As the slit 14 of the strip-shaped ePTFE body 13 with slits is widened in the width direction (black arrow direction), a space 15 is formed at the center of the strip-shaped ePTFE body as shown in FIG. 6B. The longitudinal end faces are valley-folded. Then, as shown in FIG.
The space 15 formed in the central portion of the PTFE body becomes circular, and the longitudinal end faces that are valley-folded are joined together,
It becomes the A type ePTFE ring 13A. FIG. 6 (c)
In the figure, 16 indicates a joint portion in which the end faces in the longitudinal direction are valley-folded and the facing surfaces forming the valley are joined. Junction 1
The length of 6 is about w / 2.

As shown in FIG. 6 (c), the ePTFE ring used as the core material of the covering type sealing material has a slit-shaped ePTFE body 13 expanded to form an annular shape A.
In addition to the type ePTFE ring 13A, this A type eP
180 ° so that the inner circumference of the TFE ring 13A becomes the outer circumference
A twisted ePTFE ring (hereinafter referred to as "B type") or an ePTFE ring twisted by 90 ° (hereinafter referred to as "C type") so that the inner peripheral surface or the outer peripheral surface of the A type ePTFE ring 13A contacts the tightening surface. May be used. FIG. 7 (a) shows an A type ePTFE ring 13A, and FIG. 7 (b) shows an A type ePTFE ring 13A.
FIG. 7C shows a B type ePTFE ring 13B obtained by twisting the FE ring 13A by 180 ° in the direction of the black arrow, and FIG. 7C shows a C type obtained by twisting the A type ePTFE ring 13A by 90 ° in the direction of the white arrow. Figure 13C shows an ePTFE ring 13C. The joint 16 is an A type e
It is located on the outer peripheral surface of the PTFE ring 13A (see FIG. 7).
(A)), the B type ePTFE ring 13B is located on the inner peripheral surface side (FIG. 7 (b)), and the C type ePTFE ring 13C is located on the upper surface (FIG. 7 (c)).

The ePTFE used in the first embodiment can be used as the ePTFE which is a constituent material of the slit-shaped strip ePTFE body 13. Due to the flexibility of ePTFE, the slits can be widened or twisted further 90 ° or 180 ° after widening and thus easily deformed into an annular shape.

The longitudinal length L of the strip-shaped ePTFE body 13 with slits is preferably at least twice the width W of the strip-shaped ePTFE body 13, more preferably at least 5 times, and its upper limit is preferably 300 times. , And more preferably 10
It is 0 times or less. If it is less than 2 times, the striped eP with slit
This is because the width-direction length W is large relative to the length-direction length L of the TFE body 13, which makes it difficult to deform into the ePTFE ring. That is, in the state where the ePTFE ring is deformed, the difference between the outer circumference and the inner circumference increases as W / 2 corresponding to the length of the joint 16 increases. In order to form such an ePTFE ring by deformation, the cut length of the slit 14 must be shortened, and the space 15 formed by the expansion of the slit 14 becomes too small. On the other hand, when it exceeds 300 times, the width W becomes too small due to the relationship with the length L, and it is difficult to form the slit 14, or the radial thickness of the ePTFE ring obtained by deformation (ePTFE ring's thickness). (Equivalent to the difference between the outer diameter and the inner diameter) becomes too small, and the role of the core material of the coating type sealing material becomes substantially insufficient, and the radial direction of the sealing material (fluid leakage direction)
Because it becomes weak against the force applied to.

Width W of banded ePTFE body 13 with slits
Is appropriately determined according to the radial length required for the ePTFE ring so that it can serve as a core material. In addition, the thickness D of the strip-shaped ePTFE body 13 with slits is appropriately determined according to the axial length of the ePTFE ring so as to obtain the compression amount required for accommodating the unevenness of the tightening surface.

The slit 14 of the strip-shaped ePTFE body 13 with slits is formed by punching the strip-shaped ePTFE body with a Thomson type or by cutting it with a plotter cutter, a water jet cutter or the like. Slit 1
The width of 4 is appropriately determined depending on the type of cutter used to form the slit 14, the porosity of the strip-shaped ePTFE body, and the like.

The slit 14 of the strip-shaped ePTFE body 13 with slits is cut so that it can be deformed into an annular shape by expanding in the width direction of the strip-shaped body. That is, the length m between the end of the slit 14 and the end face in the longitudinal direction is a length required to deform the slit 14 into a circular shape. Specifically, a strip-shaped ePTFE body 1 with slits
The width W of 3 is preferably 0.001 times or more, and more preferably 0.005 times or more. If it is less than 0.001 times, the length m between the slit end and the end face in the longitudinal direction becomes too small,
This is because the strength of the fulcrum when the slit 14 is widened is weakened. On the other hand, the length m between the slit end and the end face in the longitudinal direction is preferably 0.5 times or less the width W, more preferably 0.1 times or less. This is because if it exceeds 0.5 times, m becomes too large and it becomes difficult to widen the slit, and it is difficult to join the end faces in the longitudinal direction that are valley-folded when widening.

In the strip-shaped ePTFE body with slits,
At the end of the slit, as shown in FIG.
May be attached. Rounded 14 'at the end of the slit 14'
This is because the provision of a facilitates the operation of widening the slit 14 'and disperses the stress concentration on the slit end portion.

As for the strip-shaped ePTFE body with slits, as shown in FIG. 9, the end face in the longitudinal direction may be obliquely cut at an angle α so that the slit forming surface has a parallelogram shape. For example, a flat ePTFE sheet of thickness D
Such a band-shaped ePTFE body can be directly obtained by cutting at an angle α and obliquely cutting. Furthermore, the longitudinal end face does not have to be formed in one face, for example,
As shown in FIG. 10, the end face in the longitudinal direction is a valley portion v toward the slit 14 of the strip-shaped ePTFE body 13 ″ ′ with slits.
It may be formed in a V-shape having. Since the V-shaped end surface is valley-folded so as to form a V-shape with a narrower angle with the valley portion v as a fulcrum, it is especially useful for A-type ePTFE.
This is because when the ring is formed, the substantial joining of the end faces becomes more reliable.

Further, as shown in FIG. 11 (a), the engaging recess 1 is formed on one of the end faces in the longitudinal direction which are valley-folded.
8 may be provided, and the engaging convex portion 19 may be provided on the other surface. The longitudinal end surface provided with the engaging concave portion 18 and the engaging convex portion 19 is formed into a concave shape by valley fold as shown in FIG. The engagement protrusions 19 engage with each other to form the engagement joint portion 16 '. The engaging joint portion 16 'has a higher joint strength than the joint portion 16 in which the longitudinal end faces are substantially joined by valley folds, and prevents the action of the widened slit 14 trying to return to the closed state. Since it can be done, the annular shape is stable. When forming the engaging concave portion and the engaging convex portion, the shape of the engaging portion may be various shapes such as a circular shape and a square shape in addition to the trapezoidal convex portion (concave portion) as shown in FIG. Can be adopted.

B type e twisted 180 degrees into an annular shape
For the PTFE ring 13B, a strip-shaped ePTF with slits
Twice the length L of the E body 13 in the longitudinal direction (2 × L) is longer than the inner length of the slit 14 (corresponding to twice the slit cut length) by (2 × m). Therefore, the force that tries to match the short inner circumference becomes a force that pushes the longitudinal end faces at the joint portion 16, and the restoring force that causes the joint portion 16 to separate and return to the original state does not work. This stabilizes the finally obtained state of the ePTFE ring 13B.

C type eP twisted 90 ° into an annular shape
The TFE ring 13C has a strip-shaped ePTFE with slits.
It is particularly effective when the end faces in the longitudinal direction of the body 13 are formed in parallel and obliquely. That is, C obtained by twisting the slit-shaped strip ePTFE body 13 ″ shown in FIG. 9 by 90 °
In the type ePTFE ring, as shown in FIG. 12, the joint portion 16 ″ is formed obliquely with respect to the axial direction of the ring, and when the upper surface of the ePTFE ring comes into contact with the clamping surface and is clamped, the joint portion 16 ″ is tightened. 16 "will be pressed. This makes it possible to ensure the integration of the joint 16 ″.

As described above, in the core material of the second embodiment,
Since the strip-shaped ePTFE body is used as the constituent material as in the first embodiment, an expensive ePTFE sheet material can be effectively used in the manufacture of the core material, and further, a joint that penetrates from the inner peripheral surface to the outer peripheral surface in the state of the ePTFE ring. (Or connection) part does not exist. Therefore, even though the strip-shaped ePTFE body is used as the material, higher integrity is obtained in the state of the ePTFE ring. still,
The ePTFE ring used in the second embodiment has a more stable ring shape than that of the first embodiment, but it is preferable that the ePTFE ring be fixed to the annular outer skin material in order to keep the ring shape stable.

[Third Embodiment] In the coating type sealing material of the third embodiment, as a core material, a slit is cut in the longitudinal direction of a strip-shaped ePTFE body, and a V-shaped cut is formed on the side edge of the strip-shaped ePTFE body. Notched band-shaped eP with notch
A TFE body having a slit widened in the width direction and further twisted 180 ° so that the inside of the slit is on the outer peripheral side and deformed into an annular shape is used. As the annular skin material, the one used in the first embodiment can be used, and the method of attaching the ePTFE ring with the annular skin material can also be performed by the same method as in the first embodiment.

The core material used in the sealing material of the third embodiment will be described below.

FIG. 13A shows a notched strip ePTFE body 23 which is a constituent material of the core used in the third embodiment, and FIG. 13B shows this notched strip ePTFE body 23.
13C shows a state in which the slits 24 are expanded in the width direction of the strip, and FIG. 13C shows a D-type ePTFE obtained by expanding the slits 24 and then twisting 180 ° so that the inside of the slits 24 becomes the outer peripheral surface. The ring 23D is shown.

As the strip-shaped ePTFE body which is a constituent material of the notched strip-shaped ePTFE body 23, the same strip-shaped ePTFE body as that used in the second embodiment can be used. That is, the strip-shaped ePT of the first embodiment
It is made of the same ePTFE as the FE body and may be an integral body or a film laminated body. In the case of a film laminate, the ePTFE film may be laminated in the width direction of the band-shaped body or may be laminated in the thickness direction.

The slit 24 cut in the longitudinal direction of the notched band-shaped ePTFE body 23 is a banded ePTFE with slits.
It is preferable to cut under the same condition as the slit of the FE body (the distance m between the slit end and the end face in the longitudinal direction of the strip).

The size of the V-shaped notch portion 25 provided on the side end surface of the notch strip ePTFE body 23 (the notch depth p,
The notch width q) and the number are not particularly limited, but are preferably as follows.

The cut depth p of the V-shaped notch 25 is
It is preferably about 1/2 to 1/50 of the width (w) of the strip. This is because if the depth is too deep, the distance between the V-shaped tip of the V-shaped notch portion 25 and the slit 24 becomes too short, which may cause cutting in the work of deforming into an annular shape. On the other hand, if the depth is too shallow, it is necessary to increase the number of the V-shaped notches 25 or increase the V-shaped formation angle because of the relationship with the notch width q of the V-shaped notches 25 described later. This is because the notch work becomes complicated.

The number of V-shaped notches 25 is 10 to 50.
The number of pieces is preferable. Further, the width q of the V-shaped notch portion is determined according to the number of V-shaped notch portions 25 formed on the side edge of the strip body. That is, the total number of the V-shaped notches 25 is the total length of the notches remaining on the side edge of the ePTFE body as e.
The inner circumference of the PTFE ring is preferably equal to or larger than the inner circumference, and more preferably about 1.0 to 1.1 times the inner circumference of the ePTFE ring. This is because it is easier to maintain the annular shape by setting the length slightly longer than the inner circumference.

The longitudinal end face of the notched strip 23 is
The notch is formed so that a V-shape is formed when the start end and the end of the strip are connected. In FIG. 13 (a),
A pair of corner ends at diagonal positions of the longitudinal ends are notched in parallel (longitudinal end face notch 26).

The method of forming the V-shaped notch portion 25 from the band-shaped body is not particularly limited, but it is formed by punching the band-shaped body with a Thomson type or by punching with a plotter cutter, water jet cutter or the like.

A large number of V-shaped ePTFE pieces produced by notching the V-shaped notched portion 25 from the band-shaped body have no other purpose of use and therefore are discarded, but the amount thereof is punched out from the conventional ring-shaped material. It is much less than the rest, and the amount is more pronounced as the size of the ring increases.

Notched band-shaped eP having the above structure
After expanding the slit 24 in the width direction, the TFE body 23 follows the case of the B type of the second embodiment (see FIG. 13).
(B)) Twist by 180 ° so that the side edge of the band-shaped body provided with the V-shaped notch is on the inner peripheral side of the ePTFE ring (FIG. 13 (c)). In the use state after being twisted by 180 °, the V-shaped notch portion 25 has the opposing surfaces forming the V groove joined to each other (joint portion 27) to form the inner peripheral surface.

Based on its flexibility, the ePTFE body can be deformed so as to appropriately absorb the difference in length.
However, if the size of the ePTFE ring (ring outer diameter) becomes large or the ring width (corresponding to the difference between the outer diameter and the inner diameter of the ring) becomes large and the difference between the inner circumference and the outer circumference of the core ring becomes large, the ePTFE body The inherent flexibility alone cannot absorb the difference in length. In particular, in the second embodiment B type, since the longer outer circumference of the band-shaped body is deformed to become the shorter inner circumference of the ring, when the difference in length becomes large, the annular shape is independently retained. Difficult to do. In this respect, in the first embodiment and the second embodiment, the annular shape is held by being fixed to the annular outer cover material, but in the third embodiment,
The ring shape can be formed and maintained by itself without being fixed to the annular outer cover material. In addition, a V-shaped notch is provided on the side edge that occupies most of the outer circumference of the band to reduce the difference in length, so that a core material that can be adapted to a wide range of ring sizes and ring widths is provided. be able to.

[Fourth Embodiment] The coating type sealing material of the fourth embodiment is characterized in that an ePTFE ring with a support, which is formed by supporting an ePTFE ring made of a band-shaped ePTFE body on a support, is used. EPTF supported
As the E ring, the ePTFE ring described as the core material in the first to third embodiments can be used.

FIG. 14 shows an example of the core material used in the fourth embodiment. The core material 31 is a support body 32.
EPTFE ring 33 supported on the upper and lower surfaces of the
The core material used in the first embodiment, that is, the ePTFE ring formed by connecting the starting end and the terminating end of the band-shaped ePTFE body is used as a and 33b. The connecting portion 34a of the ePTFE ring 33a supported on the upper surface and the connecting portion 34b of the ePTFE ring 33b supported on the lower surface are connected to each other so that they are located on the same radial direction of the ring.
a and 34b are separated by 180 °.

The support 32 is preferably made of a material having high rigidity, and specifically, a metal ring is used. The thickness of the metal ring is preferably 0.1 to 5.0 mm. If it is less than 0.1 mm, it is difficult to fulfill the role of a support, and if it exceeds 5.0 mm, the length of the supported ePTFE ring in the axial direction must be reduced because of the restriction with the thickness of the core material. This is because this leads to a reduction in the amount of compression as the core material, and it becomes difficult to deal with a tightening surface with severe irregularities. Also, in the case of long-term use, the metal ring may be corroded by the fluid that has penetrated the skin material, which may affect the sealing performance.Therefore, the thickness of the metal ring should be as thin as possible within the range where rigidity can be maintained. Is preferred. The metal ring may be corrugated to enhance rigidity with the thin metal ring.

The outer diameter and inner diameter of the metal ring are appropriately determined according to the size of the ePTFE ring to be supported.
Less than or equal to the supported ePTFE ring, ie, e
It is preferable that the inner diameter is equal to or larger than the inner diameter of the PTFE ring, and the outer diameter is equal to or smaller than the outer diameter of the ePTFE ring. This is because the support is sufficient as long as it can play the role of maintaining the shape of the core material, and the increase in the volume occupied by the support in the core material leads to deterioration of the sealing property.

The ePTFE ring supported by the support may be a ring-shaped ePTFE body as shown in the first embodiment, or may be an annular one as shown in the second embodiment. A ring-shaped ePTFE body may have an annular shape formed by widening a slit cut in the longitudinal direction in the width direction, or may have a 90 ° or 180 ° twisted shape, or the third embodiment. A slit is cut in the longitudinal direction of a strip-shaped ePTFE body as shown in the form, and a V-shaped notch is provided on the side edge thereof, the slit is widened into an annular shape, and further twisted by 180 °, It may be an ePTFE ring having an inner circumference at the portion where the V-shaped notch portion was provided. The ePTFE rings supported on the upper surface and the lower surface of the support may be of the same type, or the ePTFE rings of different embodiments may be used in combination. Band-shaped eP used in the first embodiment
When the ePTFE rings formed by connecting the TFE bodies are used in combination, it is preferable that the connecting portions do not have the same position with the support interposed therebetween, and more preferably the same diameter as shown in FIG. The angle formed by both connecting portions is 180 ° so that they are located on the line.

An eP with a support having the above structure
The TFE ring is effective as a core material for a large-sized sealing material in which it is difficult to maintain the shape and handle the ePTFE ring when the ePTFE body alone is used. Also, the first embodiment and the second
In the case of the ePTFE ring used in the embodiment, by using the ePTFE ring with a support, the ring shape of the core material can be retained without fixing the core material to the annular outer skin material.

When forming a large-diameter ePTFE ring, it may be more effective in terms of material supply to connect a plurality of strip-shaped ePTFE bodies to form an annular shape.
In this case, since the annular shape can be formed while the ePTFE body is stuck and fixed on the support, the desired annular shape can be easily formed, which is convenient.

On the support 32, the ePTFE ring 33a,
As a method for supporting 33b, sticking with an adhesive or a double-sided adhesive tape is preferable. These are convenient from the viewpoint of workability, and the thickness of the adhesive part is very thin compared to the thickness of the entire sealing material, and the tightening force enhances the adhesion between the support and the ePTFE ring. Even if the agent part is deteriorated, it hardly affects the sealing property.

As the adhesive that can be used, the adhesive or the adhesive tape used in the first embodiment for connecting the start end and the end of the strip or fixing it to the annular outer cover material can be used. Specific examples include acrylic and rubber-based adhesives, and among these, acrylic adhesives are preferable because they have excellent heat resistance.

[0066]

EXAMPLES The present invention will be described below based on specific examples. [Measurement of Sealing Property] The sealing properties of the annular sealing materials produced in the following Examples and Comparative Examples were measured using the measuring container shown in FIG.

First, JIS 10K-250A equivalent
The glass lining container 41 having the size of
I covered it with. In this state, the bolt position P of the lid 42₁
~ P_{1 2}Between the upper surface of the container 41 and the lid 42 at
Was measured.

Next, the lid 42 is opened, and the opening 4 of the container 41 is opened.
Set the covering type sealing material 44 created around the upper surface of No. 3 and cover the lid 42 again with 120N per bolt.
Tightened with a torque of m. At this time, the position of the lid 42 was made to coincide with that when the sealing material was not interposed.

In this state, compressed air was blown into the container 41 to increase the internal pressure to 0.5 MPa. Around the sealing material 44, soapy water was evenly sprayed, and the presence or absence of bubbles at the bolt positions P _{1 to} P ₁₂ was visually inspected. It can be seen that if no bubbles are generated, it is hermetically sealed.

[Production of Sealing Material] (1) Example 1 From a commercially available rectangular ePTFE sheet having a thickness of 3 mm (Hyper sheet manufactured by Japan GORE-TEX Co., Ltd.),
Band-shaped ePT with a length of 485 mm, a width of 50 mm, and a thickness of 3 mm
The FE body was cut out and a double-sided adhesive tape (# 9458 manufactured by Sumitomo 3M Limited) was attached to one side of the FE body. A slit having a length of 483 mm was formed in the center of the obtained strip-shaped body to obtain a strip-shaped ePTFE body as shown in FIG. 6 (a).

While expanding the slits of the strip-shaped ePTFE body with slits on the upper surface of a steel annular support having an inner diameter of 270 mm, an outer diameter of 320 mm and a thickness of 0.5 mm,
While twisting 180 °, the ePTFE body was attached so as to be concentric with the support to form an ePTFE ring. Similarly, an ePTFE body was attached to the lower surface of the support to form an ePTFE ring, and a core material with a support was prepared. At this time, the joint portion 16 of the ePTFE ring supported on the upper surface and the connection portion 16 of the ePTFE ring supported on the lower surface were arranged so as to be offset by 90 °.

The core material prepared above was inserted from the outer peripheral opening into an annular skin material having an inner diameter of 250 mm, an outer diameter of 325 mm, and a thickness of 0.4 mm of the type shown in FIG.

(2) Example 2 From a commercially available 6 mm thick ePTFE sheet (Hyper sheet manufactured by Japan GORE-TEX Co., Ltd.), a length of 480 mm,
A band-shaped ePTFE body having a width of 50 mm and a thickness of 6 mm is cut out. A slit having a length of 483 mm is formed in the longitudinal center of the strip along the longitudinal direction, and a notch width q = 3.5 mm and a notch depth p = 22 mm are further provided at the end on the side of the strip.
Insert 20 V-shaped notches on each side edge, and
A notched band-shaped ePTFE body as shown in 3 (a) was prepared. The slit of the notched band-shaped ePTFE body is widened, and then twisted by 180 °, and as shown in FIG. 13C, the notched portion is deformed into an annular shape with the inner peripheral side, and the outer diameter is about 310 mm. , EPTF with an inner diameter of about 260 mm and a thickness of 6 mm
I got an E-ring.

This ePTFE ring was inserted into the same annular outer jacket as in Example 1 through the opening on the outer peripheral side to obtain a coated type sealant.

(3) Example 3 From a commercially available rectangular ePTFE sheet having a thickness of 3 mm (Hyper sheet manufactured by Japan GORE-TEX Co., Ltd.),
980 mm long, 25 mm wide, 3 mm thick strip ePT
Two FE bodies were cut out, and a double-sided adhesive tape (Sumitomo 3M # 9458) was attached to one surface of each strip. Further, both ends of the strip in the longitudinal direction were cut at an angle θ = 10 ° so as to be oblique and parallel.

A steel support having an inner diameter of 270 mm, an outer diameter of 320 mm, and a thickness of 0.5 mm was prepared, and was adhered to both sides of the support while peeling off the release paper of the adhesive tape of the belt-like body. Then, the cut surfaces at the beginning and the end of the strip were overlapped to form a circular ring. Here, the connecting positions of the start end and the end of the ePTFE ring formed on the upper surface of the support and the ePTFE ring formed on the lower surface are
It was set to be 180 ° off. In this way, a core material with a support was formed.

The core material prepared as described above was inserted into the same outer ring material as in Example 1 through the opening on the outer peripheral side to obtain a coating type sealing material.

(4) Comparative Example 1 Outer diameter 320 mm, inner diameter 2 on both sides of an asbestos joint sheet having outer diameter 320 mm, inner diameter 270 mm, thickness 0.8 mm
Asbestos felt having a thickness of 70 mm and a thickness of 0.8 mm was adhered to form a ring body, and two further ring bodies were superposed to prepare a core material.

The core material produced as described above was inserted into the same outer ring material as in Example 1 through the outer peripheral opening to obtain a coating type sealing material. [Evaluation] For the coating type sealing material produced above,
The sealability was evaluated based on the above evaluation method. The results are shown in Table 1.

[0080]

[Table 1]

As shown in Table 1, in P _{6 to} P ₈ , 0.7 to
There was a relatively large gap of 0.9 mm. Even in such a bolt position, no leakage was observed when the coated type sealing material of the present invention was mounted, but in the coated type sealing material using the conventional asbestos as the core material,
In the position of the P ₆ ~P _8, the generation of foam was observed. That is, it can be seen that a leak has occurred at this position.

Regarding the handling property, Example 2 without a support, Examples 1 and 3 using a core material with a support,
Comparative Example 1 using asbestos as the core material, there was no difference in any case.

[0083]

Since the core material of the coated type sealing material of the present invention is made of ePTFE, even if it is a rough surface having a large number of irregularities, it is possible to seal without gaps.

Moreover, since the core ePTFE ring is made of a band-shaped ePTFE body, an expensive ePTFE sheet can be used without waste in manufacturing the ePTFE ring. Further, by using the band-shaped ePTFE body, it is possible to provide a large-diameter coated type sealing material which cannot be sized in a sheet punching process.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a coating type sealing material according to a first embodiment of the present invention.

FIG. 2 is a view for explaining a core material and an annular outer cover material used in the covering type sealing material shown in FIG.

FIG. 3 is a diagram for explaining the production of a band-shaped ePTFE body.

FIG. 4 is a diagram for explaining the production of a band-shaped ePTFE body.

FIG. 5 is a diagram showing a configuration of another embodiment of the annular outer cover material.

FIG. 6 is a diagram for explaining a banded ePTFE body with slits and a state of being deformed into an annular shape.

FIG. 7 is a diagram showing a configuration of a core material used in the second embodiment.

FIG. 8 is a diagram showing another embodiment of the slit.

FIG. 9 is a view showing another embodiment of a strip-shaped ePTFE body with slits.

FIG. 10 is a view showing another embodiment of a strip-shaped ePTFE body with slits.

FIG. 11 is a view showing another embodiment of the joint portion of the ePTFE ring.

FIG. 12 is a view showing another embodiment of the joint portion of the ePTFE ring.

FIG. 13 is a view for explaining a core material used in the third embodiment.

FIG. 14 is a diagram showing a configuration of a core material used in the fourth embodiment.

FIG. 15 is a diagram for explaining a method of measuring the sealing property used in the examples.

FIG. 16 is a diagram for explaining a problem of a conventional core material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ePTFE ring 1a Connection part 2 Annular skin material 2b Connection part 3 Strip-shaped ePTFE body 4 Two-fold sheet 13, 13 ', 13 ", 13"' Slit strip e
PTFE body 13A, 13B, 13C ePTFE ring 14, 14 'slit 23 notched belt-shaped ePTFE body 23D ePTFE ring 24 slit 25 V-shaped notched portion 27 joint portion 31 core material with support 32 support body 33a, 33b ePTFE ring

Claims (10)

[Claims] 1. A stretched porous polytetrafluoroethylene ring (hereinafter referred to as "eP") made of a strip-shaped stretched porous polytetrafluoroethylene body (hereinafter referred to as "ePTFE body").
(Hereinafter referred to as "TFE ring"), and a coating type sealing material including a ring-shaped outer cover made of baked polytetrafluoroethylene that covers the outer surface of the core. 2. The coated type sealing material according to claim 1, wherein the core material is formed by connecting both longitudinal end surfaces of the strip-shaped ePTFE body to form an annular shape. 3. The strip-shaped ePTFE body has slits cut in the longitudinal direction, and the ePTFE ring is formed by expanding the slits in the width direction and deforming into an annular shape. Cover type sealing material. 4. The strip-shaped ePTFE body has slits cut in the longitudinal direction, and the ePTFE ring is formed by widening the slit in the width direction and deforming into an annular shape, and thereafter, the upper surface of the strip-shaped ePTFE body or The covering type sealing material according to claim 1, which is folded back so that a lower surface thereof becomes an outer peripheral surface to form an annular shape. 5. The strip-shaped ePTFE body has slits cut in the longitudinal direction, and the ePTFE ring has an inner side surface of the slit which is expanded after the slit is widened in the width direction and deformed into an annular shape. 2. A ring-shaped member that is folded back to form a surface.
The coated sealing material described in. 6. The covering type sealing material according to claim 1, wherein the ePTFE ring is fixed to the annular outer covering material. 7. The side edge of the strip-shaped ePTFE body,
The covering type sealing material according to claim 5, wherein a plurality of V-shaped notches are formed, and the facing surfaces of the notches forming the V groove are joined to form an inner peripheral surface. 8. The covering type sealing material according to claim 7, wherein the total length of the notched portions at the side edges of the strip-shaped ePTFE body is equal to or greater than the inner peripheral length of the ePTFE ring. 9. The coated sealing material according to claim 1, wherein the ePTFE body is a laminate of ePTFE films. 10. The core material includes two ePTFE rings and a ring-shaped flat plate made of metal, and the first ePTFE ring is supported on an upper surface of the flat plate.
The coated type sealing material according to any one of claims 1 to 9, wherein the second ePTFE ring is supported on the lower surface of the flat plate.