MXPA98007027A - Board resistant to faults by compression to high pressure and high sell - Google Patents

Abstract

The present invention relates to a package characterized in that it comprises: a base sheet of an essentially contiguous, flat packing material having a predetermined thickness and two opposite faces essentially parallel, the base sheet being configured to define at least one interior opening joined by a relatively porous edge of the base sheet, an edge covering is disposed at the relatively porous edge of the base sheet, the edge covering penetrates at least partially on the relatively porous edge and is shaped and configured to provide a seal improved when the package is compressed between a pair of flange surfaces, the opposite faces of the base sheet lie in respective, separate facial planes and the edge covering has edge portions adjacent to the facial planes, an intermediate central portion to the facial planes, a thickness in a direction essentially parallel to the p Facial lans and a width in a direction essentially perpendicular to the facial planes, a face covering on a portion of at least one face of the base sheet, the face covering extends on a strip around the opening and has one thickness and one width, the face coating covers less than about 30% of the

Description

FAILURE RESISTANT GASKET BY HIGH PRESSURE COMPRESSION AND OF HIGH SEALING BACKGROUND OF THE INVENTION Field of the invention The required performance characteristics of many joints include resistance to compression failures and sealing capability. Joints should often be in operation under pressures * in the range of approximately 211 Kg / cm2 (3,000 psi) to approximately IO 2109 Kg / cm2 (30,000 psi (pounds per square inch)). At the same time, the joints are required to provide a seal against fluids. In some instances, in order to provide a good seal, the boards are covered to obtain capacity for sealed. Fibrous joints or soft porous materials are types of joints to which coatings are provided, since these joints are very porous and have problems giving an adequate seal for use. Unfortunately, the coating used to give sealing ability penetrates the joint and reduces the ability of the joint to withstand pressure. It would be beneficial to develop a joint which provides a good sealing capability which, at the same time, is resistant to compression failure, especially if the joint could be put into operation at flange or flange pressures REF. 28228 in the range of approximately 1.4 Kg / cm2 (20 psi), to approximately 2109 Kg / cm2 (30,000 psi). Gaskets which are known in the prior art include the gaskets described in US Patent 3,661,401 which requires that the gaskets be provided with a coating which covers the walls of the openings in addition to the faces of the gaskets. However, such joints, being completely coated, will function poorly at such high pressures. This severely limits the field of use of the boards. The present invention beneficially provides seals which have an appropriate sealing capability and are resistant to compression failure. They are supplied together which are capable of withstanding operating pressures of at least 211 Kg / cm2 (3,000 psi). In addition, joints are provided which will function well in the range of approximately 1.4 Kg / cm2 (20 psi) to approximately 2109 Kg / cm2 (30,000 psi); The present joints, remarkably, have the ability to seal at high and low flange or flange pressures.

BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, a soft joint material has two opposite surfaces (sides), the joint has an edge perpendicular to the facial surfaces. The edge has a surface to which a coating is provided. Where the edge is over an opening, the coating on the edge of the opening provides the seal with a primary seal against leaks of fluids that would come from the opening through the porous edge of the soft seal material and the gasket. A coating on a perimeter edge provides only a secondary seal. However, the opposing facial surfaces have only a limited coating in order to preserve the resistance to compression failures. While more coating is provided to the face of the joint there is less resistance to compression failures. By having a portion of the surface of the board uncoated, a better resistance to compression failure is provided than the joint would have with a sealing coating on at least some of the surface without • coat. The release coatings are allowed and optionally, in any given application, the gasket can be provided with a release coating which does not cause compression failures. Preferably, no coating for sealing capability can be made over the joints, which would cover more than about 50%, either on one or both sides. More preferably, for more resistance to compression failures, no more than about 30% of expensive arabs are coated to obtain sealing capability. More preferably, in effect, the opposing facial surfaces are not substantially coated with sealing coatings. By having substantially no coating on either side of the joint, the joint will be given a better resistance to compression failure than the joint would have if the joint itself had a coating of up to approximately 30% on both sides or even on some portion of at least one side. The coating allowed on the opposite facial surfaces (the face) is limited to: 1) a sealing coating on one or both sides of the joint while leaving uncoated portions on one or both sides of the joint, the portions without Coating of the joint is present in an effective amount to give the joint better resistance to compression failure than it would if at least a portion of the uncoated surface were coated and / or 2) release coatings which do not they substantially affect the resistance to compression failure and do not substantially penetrate the joint. Properly, the coating on the edge covers all the edge portions which must be coated in order to provide the seal with a good sealing capability. Preferably, however, the entire edge is coated. The coating of the entire edge will allow the joint to provide a better seal. However, acceptable embodiments include instances where the coating covers the major portions of the edge. Thus, the edge can be coated in an effective amount to obtain a substantial seal of the joint along the edge of the opening. The edge can be coated, for example, up to approximately 75% of the edge of the opening. Such modalities can be used for a good sealing ability, where the best sealing capacity obtained from coating the entire edge of the joint does not have to be used. If, for example, a bolt area is found near the opening, the high pressure near the bolt may decrease the need for full edge coverage. An area of expertise is an area near or under the bolt where the highest pressure is applied to the joint that is in areas away from the bolt. In another embodiment, the edge of the sheet material of the joint contains pores in which the coating material on the edge has penetrated. This helps to seal the pores and gives the sheet or sheet of the joint a better sealing capacity. A wide coating of the edge on one edge of the joint sheet, which covers the edge from corner to corner and extends beyond the corner, protruding beyond the corner plane (beyond the corner) in one direction perpendicular to the facial plane, it will provide the joint with a better sealing capacity, especially since it can seal against two types of fluid flow; through the board and through the face of the board. This is particularly true for an edge which has been cut off at the joint. The cut edge will have more pores than another surface which is not cut even in porous and compressible joints. The coating of the edge in such a way that the coating penetrates or closes the pores will be effective to seal the pores to the fluid which could infiltrate through the joint. Where a joint has the edge of the coated opening and a coating on a portion of at least one face, which is connected to an opening and forms a border around the opening, the edge covering is arbitrarily designated as coating A (in this description) while the coating on the face that is connected to the opening is designated as coating B; a coating on the edge which is around the outside (periphery) of the joint material is the coating C. Different coating materials can be used to form the coatings A and B, although it is also permissible to coat the different areas with the same coating material. As more coating for sealing capability is applied to the joint faces, the performance of the joint in response to higher pressures will be impaired, even if the coating on the face is limited to a coating strip that is splice the coated edge of the opening over at least one side of the joint. Therefore, for this reason, it is preferred that the coating B, which is spliced with the coated edge of the opening, should be limited in width, such that it covers only a limited portion of the face (s) of board. Preferably, the coating (coating B) on at least one side of the joint, which is connected to the coated edge of the opening, can be up to about 1.5 cm wide on the face. Preferably, such cover strips on the face of the gasket and which are connected to the opening, can cover up to about 50% of one or both sides. * As the data of Example 8 demonstrate herein, for the preferred embodiments, it may also be important to limit the thickness of the coating on each face of the joint. The thicker the coating on the face of the joint, the lower the pressure at which the compression failures of the joint occur. Thus, coatings for sealing which are applied on the face of the gasket are preferred, such that they are a maximum of about 11 mils in thickness.

DESCRIPTION OF THE DRAWINGS The figures included herein show examples of certain embodiments of this invention. Figure 1 shows a soft seal material (10) which has been cut for a flange or flange. The gasket has a large opening and four smaller bolt holes. The gasket has a coating strip (11) around the opening on the face of the gasket. The gasket also has a coating (12) on the vertical edge around the opening. The covering (12) covers the entire vertical edge and is made of a coating material different from that of the coating strip (11) • Figure 2 provides another view of the gasket sheet shown in Figure 1. The soft gasket material (10) is seen with a cover strip (11) on each side around and which is attached to the opening . On the edge, which is perpendicular to each face and is around the opening, is the coating (12). A vertical edge (23) of the joint material is also seen. Figure 3 shows a soft seal material (13) which has been cut to a flange or flange. The gasket has one opening and four smaller bolt holes. The gasket also has a covering (14) which covers the entire vertical edge around the opening. Figure 4 provides another view of the seal sheet shown in Figure 3. The soft seal material (13) is seen with a coating (14) on the edge (23) which is perpendicular to each face and is around of the opening. Figures 5-12 show configurations of various edge coatings. In Figure 5, the covering (16) on the vertical edge (71) of the joint does not overlap one corner or the other of the edge of the joint, but protrudes beyond the corner planes (29) and (30) (also called facial planes, since the planes contain faces (15) and (50)). Thus, the covering is not located on either one of the horizontal faces of the joint such as the covering (18) in Figure 6 and the covering (22) of Figure 8. In Figure 5, the thickness (or width) of the cover (16) in the direction parallel to the vertical edge of the joint becomes gradually larger as it separates from the joint. The coating is wider than the vertical edge (71). The embodiment of Figure 5 provides a seal with a sealing capacity that fluctuates from a good seal to a total seal and simultaneously provides the best resistance to compression failure (optimum) since none of the faces of the joint has any coating to seal the board. The planes (29 and 30) are shown in figure 5, which are facial planes (containing the face of the board) and corner planes (which advance through the corner of the board between the face and the edge) . Similarly, Figure 9 shows the facial, corner planes (37) and (38); Figure 10 shows the partial, corner planes (39) and (65) and Figure 12 shows the facial plane (60). Figure 11 has a facial plane (31) containing the face (40) and also has a corner plane (82) which advances through the corner between the face (40) and the vertical edge (77). In this instance, the gasket of Figure 11 has a face that has been slightly contoured by pressure applied near the edge of the opening. The corner lies between the cut portion of the edge (77) of the joint and the face surface (40). The corner plane (82) contains the point of the joint where the cut edge ends and the material of the face (40) (which contains the corner) begins.Figure 6 shows the covering (18) covering part of the face (17) and the entire edge (72). The coating advances to the corner between the edge (72) and the face (51). The covering (20) of Figure 7 covers the edge of the joint from the corner to the corner of the edge (73), thus the coating is coextensive with the edge (thus advancing from one corner plane to another). Preferred embodiments have the coating on the coated edge projecting beyond the corner planes (such as Figure 9, where the coating (26) advances beyond planes (37) and (38). The covering (18) of Figure 6 and the covering (22) of Figure 8 is also wider than the vertical edge (72) and (74) of the joints and where the coating is connected to the joint. , in Figure 6, the slight widening or tapering of a horizontal face of the gasket (17) slightly narrows a vertical edge and allows the covering (18) to wrap over the face (17) of the gasket. 8), both horizontal faces of the joint taper or widen immediately to the edge of the joint and the edge covering covers the joint slightly on each horizontal face.The taper of the horizontal face of the joint that is connected to the opening is a optional preferred modality. apply a coating on the face of the joint that joins the vertical edge, without the taper of the faces of the joint near the edge. An excellent and even total good seal can be obtained without the tapering of the joint faces on the horizontal face. The taper of the thickness of the joint on the horizontal face, near the vertical coated edge (as shown by Figure 6 and Figure 8) is an optional preferred embodiment. Another preferred embodiment is the coating of the coating (coating A) on the corner of the edge of the gasket on the face (where it is referred to as coating B). The coating can be wrapped over the vertical edge corner of one or both sides of the joint (whether the thickness on the horizontal face near the edge is tapered or not) (shown in Figures 6 and 8). For example, such a taper of the joint thickness can be made at a distance of about 0.0635 cm (1/4 inch) away from the vertical edge to the vertical edge. It can also be noted that the covering (18) of Figure 6 is slightly wider than the thickness of the joint, where the coating is joined to the vertical edge of the joint. Having a coating which is wider than the joint where the coating is spliced with the vertical edge of the gasket is another preferred embodiment. In another preferred embodiment, the coating will continue its increase in thickness by separating from the coated vertical edge (and the opening). A variation of this embodiment is shown in Figure 5. Figures 5-12 show embodiments with an edge of the joint opening coated by a coating composition. Figures 5 and 9 show alternatives to obtain an extremely effective sealing by the joint and at the same time to give a very good resistance to compression failures. Two major leaking points where the sealing ability of a joint fails: 1) through the joint (especially through the joint pores at the vertical edge) through the vertical edge of the joint and 2) through the surface of the joint, between the horizontal surface of the joint and the flange. Figures 5, 6, 8 and 9 show preferred embodiments of the joint which reduce leakage at each of these two points. Figures 5 and 9 with the wider coatings provide an even better seal than Figure 8. Figure 10 shows a coating (27) of the opening on the flange (76) which is between the face (25) and ( 53). The coating is appropriate and effective to give an adequate seal. Nevertheless, the most preferred embodiments are shown in Figures 5 and 9. The most preferred embodiments of the edge covering have a coating that is wider than the edge of the joint and thus protrudes beyond the edge, beyond the facial planes, of corner '(37) and (38) of Figure 9 and planes (29) and (30) of Figure 5. More preferably, the coating can protrude (by having a width greater than the width of the edge of the together) at least about 0.025 cm (1 mil) beyond the facial plane and any thickness of facial lining, even more preferably protruding (in a direction parallel to the edge of the joint), at least about 5 mils inch and more preferably protrudes at least about 10 mils beyond the facial plane and beyond any facial coating thickness. In suitable embodiments of the wide edge coating, it is sufficient that the edge covering protrude beyond at least one corner plane. Figure 7 shows an edge-coated gasket with a coated opening edge (73), wherein the edge covering (20), adjacent to and attaching to the vertical edge of the gasket, has substantially the same thickness as the gasket ( 10). • Figure 11 shows a joint with a tapered face (40). The edge (77) having the opening is covered by a coating (41). The covering (41) covers the edge of one corner beyond the other corner (covers the laminar edge of the joint from a corner, wherein the corner plane of the face (42) advances through the joint and beyond of the corner plane (82), to be wrapped lightly over the face (40) of the joint). In the figure you can see the facial plane (31). Figure 12 shows a joint with an edge (78) having the opening covered by a cover (48), which protrudes beyond 'the facial plane, corner (60) (the plane is a facial plane and a plane of corner). The board has embossed areas such as (49) and a cordon such as (46).

DETAILED DESCRIPTION Any porous material can take advantage of the present invention. Any soft joint material, which has at least one edge can also take advantage of the present invention. A soft joint material is a joint laminate material which is normally compressible, flexible and porous. Many types of soft joint materials comprise fiber and a binder, other types of soft joint materials comprise a binder and a filler, such as, for example, rubber and cork; preferred soft gasket materials comprise fiber, binder and filler. Soft gasket materials have pores along the vertical edges of the opening. These pores are detrimental to the sealing ability of the joint. A soft seal material can be given an edge seal on an opening exposed to the fluids and obtain a seal against the fluid. Surprisingly, there is no need to change the composition of the sheet material for any significant improvement in sealing capacity. The edge coating provides the seal. Surprisingly, in many cases there is no need for significant sealing capacity in the sheet or base sheet. In addition, a base sheet or sheet with the edge seal can accommodate many different types of flanges or flanges without making any changes to the base sheet or sheet. Gaskets which are particularly suitable for the present invention are soft gasket materials having openings or perforations which are cut into the material. The cut edges of the soft joint materials are usually more porous, since the material was cut to expose the open space to the interior of the sheet. In general, the cut edge is more porous than the face of the joint. It is highly preferred to apply a coating seal on an edge having the opening, which must seal against fluids. Since the fluid, in general, comes into contact with the joint, first at the edge having the opening, the coating of this edge is referred to as a primary seal. It may also be desirable to apply a coating (coating C) on the outer edge of the joint, either in place of or in addition to the coating in the opening. The outer edge marks the outer perimeter or circumference of the joint. The coating C on the outer edge of the joint, however, is not as advantageous as a coating on the opening. On the perimeter of the joint, the coating will form only a secondary seal against the fluids to prevent them from advancing beyond the joint. The primary seal, on the edge of the opening (coating A) is preferred. Preferred gaskets that can use the present edge seal, which improved resistance to compression failures, are gaskets for intake manifolds; Crankcase gaskets (which seal against the oil); cover joints, such as a valve cover (which seals against oil) or shaft covers (which seal against the gear lubricant); seals for water pumps, which seal against water and antifreeze; and compressor gasket applications, which are frequently exposed to refrigerants such as Freon; gas meter gaskets, exposed to gases; and flanges or industrial flanges, exposed to steam and chemical components. The type of coating for each application is important to obtain the preferred embodiments, since some particular types of coatings will retain the particular fluid better than others (some coatings have chemical interaction with the fluid). It has been found that the wide edge seal design (which has the coating protruding beyond at least one corner which falls between the face and the edge) is surprisingly suitable for sealing of crankcases and diesel engines, for the sealing of oil coolers in diesel engines and for vacuum sealing in multiple air intake and fuel blends. The chloroprene or acrylonitrile polymer are the preferred coatings for modalities with exposure to refrigerants; acrylic or acrylonitrile are the preferred coatings for modalities with exposure to oil. A preferred gasket has flat faces, although gaskets suitable for the present invention include gaskets having such characteristics as embossing on one or both sides or tapering of the gaskets at the edges of one or both sides. However, the joints have opposite planes, which are referred to herein as "facial planes" "corner planes". Corner planes advance through a corner between a face and an edge.

The planes extend infinitely and the facial planes pass through substantially flat portions of each face. The edge is substantially perpendicular to these facial planes. The corner plane is either the same as the facial plane or is parallel to it. The resistance to compression failures is the ability of a joint structure to withstand pressure without deforming the joint to the point of failure. The compression test (shown in Example 1) is an industry-accepted measurement of compressive failure resistance. The degree of resistance to compression failure that a joint must have is set by the load it will experience in a particular application or in the particular flange or flange in which it is used. In one embodiment of the present invention, the gasket sheet or sheet has a coating which penetrates the pores along the vertical edge of the opening, which is perpendicular to the opposing planes of the two flat faces of the gasket. The penetration of the coating material into the pores gives the sheet material of the joint a better sealing capacity. The joint will have uncoated surfaces in an effective amount to give the joint better resistance to compression failure, than the joint would have if at least a portion of the uncoated surface were coated with a sealing capability coating. Appropriately, 50% or less of each face is coated with a sealing coating, the compressive failure resistance of the joint is optimized and a good resistance to compression failure is obtained. For even better compression failure resistance, no more than about 30% of each joint face can be coated by a coating to seal the joint. The best resistance to. Compression failures are obtained where there is substantially no coating on one side or the other of the joint. When the sheet material of the joint comprises fiber and binder, in most cases a filler is also present. The sheet or sheet of the board must have at least 1% by weight of the binder and at least 5% by weight of the fiber. The filling can also be added to a minimum level of approximately 1%. Appropriate ranges are from about 3 to about 40% by weight of the binder, from about 5 to about 70% by weight of the fiber and from about 1 to about 92% by weight of the filler. At least one edge, which is located around an opening and substantially perpendicular to the substantially opposite faces, is provided with a coating (coating A) for a sealing capability. Where the edge is coated, the coating covers the edge from the corner of one face completely through the joint, at least to the corner of the other face. It is important to cover the edge on one side of the edge on the other side of the edge, where the coating is a barrier formed over the edge to seal the pores and / or penetrate the pores. The coating of the edge of the joint opening can be done in any manner of film formation, such as, for example, dipping or melting (as long as the portions of the joint that are not to be coated are protected) or painting . This coating on the edge provides sealing capability. In one embodiment, a coating may be applied over the edge of the opening by placing together a plurality of seal sheets, so as to form a cavity in the openings of the plurality of seal sheets and then in contacting the same. edges of the opening on each joint sheet with a coating material, such that the edges are coated in an effective amount to obtain a substantial seal of the joint along the edge of the opening where the edge is coated . The joints can be aligned and placed together in such a way that they are joined or in some of these modalities, it may be desirable to place other sheets between two or more of the joint sheets. Such sheets between the joints would be "separators" to separate the joints from each other. The separator sheets will also have openings, but the openings can be wider, smaller, or the same size as the joint openings. When the separator has a wider opening than the gasket, a portion of the face of the gasket sheet is exposed and the coating material can be contacted and coated on the face where it is exposed around the opening. When the opening of the separating sheet is smaller than the opening of the joint sheet, then the joint sheets will separate from each other and less coating will overlap the corner of the edge on the face of the sheet. In other embodiments, some of the edge of the opening may be protected from the coating material, such that only a portion of each edge of the opening on each joint sheet is brought into contact with the coating material. This may be desirable, where the edge of the opening is close to a bolt area. Where the edge of the opening is within, for example, 3.5 cm of a bolt, it may be desirable to retain even more compressive strength, by not adding coating yet to the edge. The extra pressure, added by the bolt, will be effective to give some additional sealing capability to the joint, so that it may not be necessary or desirable to completely coat the edge of the opening. To obtain such embodiments, a separator sheet is preferably configured to cover the portion of the edge which will not be coated. To seal well against fluids passing through the joint, however, the method for coating the edge of the opening should ensure that the edge portion is coated if it comes into contact with the coating material throughout the entire surface. thickness of the edge of the joint, of a corner that is connected with one face to the other corner that is connected to the other side. Any vertical edge between the opposite, parallel, flat faces of a joint sheet material, a covering, in which the edge which forms the outer perimeter of the joint, can be provided. The coating can be organic, inorganic or a hybrid of both. When the vertical edge is one which encounters fluids during use, however, a polymeric coating is particularly useful and preferred. In such cases, preferably, the entire edge is coated to obtain the best possible sealing capability of the coating. In such a case, the coating on the edge of the opening is referred to herein as a "primary seal". The coating on the edge of the opening is particularly desirable when the joint must seal against fluids. The coating of the edge, in such case, prevents the penetration of a fluid to the sheet. Optionally, a covering strip (coating B) can be applied on one or both sides completely around an opening, in such a way that it joins the edge perpendicular to each face and also splices or even joins the coating on the surface. edge of the opening (coating A). The coating strip can be used beneficially where the flanges or flanges do not fit tightly together to form a tight seal against fluids. If, for example, a ridge curves even slightly, so that it curves away from a flat (facial) surface, the liner strip can be useful to provide a better seal against fluid leakage. For such applications, the coating strip will preferably be applied around the opening, where the fluids are in use. Preferably, the coating A is wider than the joint and the coating B combined, such that the coating A protrudes at least about 0.0025 cm (1 mil) beyond the B coating on at least one side ( coating A, to thereby form a ridge above the coating B); more preferably, it protrudes at least about 0.127 mm (5 mils) and more preferably protrudes at least about 0.0254 cm (10 mils) (1 thousandth of an inch is 1/1000 inch)). A preferred range for coating A that protrudes beyond coating B is from about 0.0127 cm (5 mils) to about 0.2032 cm (80 mils) and more preferably about 0.0254 cm (10 thousandths of an inch) to approximately 0.2032 cm (80 thousandths of an inch). Reference may be made to 'the features where the coating A extends beyond the face of the joint at the corner of the edge (to protrude well beyond the corner plane) or where the coating A extends beyond of the coating B as a "flange formation" or a "flange". Such characteristics form a barrier or dam against fluids. The flanges are shown, for example, in Figures 5, 9 and 12. Optionally, each side of the joint can be provided with a release liner (to make the joint easier to separate from the flange or flange after use) which does not substantially affect the resistance to compression failures. A release coating is typically less than 0.00254 cm (1 mil) thick. For better performance, the release coating should not substantially penetrate the joint structure. The high degree of compression failure, which is caused by sealing coatings, is not normally found with release coatings. In addition, a sealing coating frequently penetrates the joint structure. The present invention provides resistance to compression failures and sealing ability to joints. Coatings on the face of the joint, which improve or provide sealing performance of the joint, will adversely affect the resistance to failure by compression and these should be limited. Such coatings are generally made with a heavier coating material than the release coatings. In other embodiments, the edge covering, on the vertical edge of the joint, can be wrapped either on one side or the other of the joint (as shown for example by Figure 6 and Figure 8). Alternatively, another coating can be added to the face that is spliced to the edge, as shown in Figure 2. In order to obtain resistance to compression failure, this overlay and the aggregate coating should be limited in both thickness as in width. Preferably, the sealing coating can however extend up to about 1.5 cm on the face of the joint, so long as the face coating of the joint is limited, to preserve the resistance to compression failure, more than preference to not cover more than about 50% of the facial surfaces. More preferably, it extends to a maximum of approximately 5 mm transverse to the face of the joint. More preferably, for even better compression failure resistance, the overlay of the edge covering (coating A) on the horizontal face of the joint is a maximum of about 1 mm. The wider this sealing coating on the face of the joint, the greater the detrimental effect on the joint resistance to faults under pressure. Thus, the thinner the strip of the coating, the better the resistance to compression failures. The sealing coating, which is allowed to coat the face of the gasket proximate the vertical edge of the gasket, should preferably be limited in thickness, in order to preserve the gasket resistance to faults under pressure. Preferably, the coating that joins the edge on the joint face should be 0.0279 cm (11 mils) or smaller in thickness. More preferably, the coating will be a maximum of 0. 0178 cm (7 mils) thick and even more preferably will be a maximum of about 0.01016 cm (4 thousandths of an inch) thick and more preferably preferably 0.0063 cm (2.5 mils) thick or smaller. The thicker the edge covering (adjacent to and that is joined to the vertical edge coated with the joint), the lower the pressure at which joint compression failures will occur. Viability is the factor that limits the thickness of the coating directly on the vertical edge, both in the direction parallel to the vertical edge and perpendicular to the vertical edge. However, it has been found that very small thicknesses are effective. Since a relatively thin coating is effective, it will be effective in cost to limit the thickness and width of the coating on the vertical edge of the joint opening. The coating on the edge of the joint opening, where the joint is to be sealed, should cover the entire edge, from one side to the other, in order to complete the seal. The joints have flat faces with opposite facial planes; the edge of the openings is perpendicular to these planes. In preferred embodiments, the coating on the edge of the opening extends beyond at least one of these opposed planes, to give a better sealing capability. Preferably, the coating at the edge of the opening, in a direction parallel to the edge, will protrude at a distance of at least 0.0025 cm (1 thousandth of an inch) beyond either one or the other opposite facial plane of at least one. a face or appropriately may protrude at least 0.0025 cm (1 mil) beyond a corner plane (as shown in Figure 11) of the joint in order to provide a better seal. An appropriate range for the distance at which the coating will extend beyond at least one opposite face plane of the joint face (as shown in Figures 5 and 6) or alternatively, beyond the corner plane, is from about 0.0025 cm (1 mil) to about 0.2032 cm (80 mil). More preferably, it stands out on each side of the board. A more preferred range for the coating to protrude beyond at least one corner plane or alternatively beyond at least one facial plane is from about 0.0127 cm (5 mils) to about 0.2032 cm (80 mils) ) and even more preferably protrudes beyond a corner or alternatively, beyond a facial plane, a distance of about 0.0254 cm (10 mils) to about 0.2032 cm (80 mils). More preferably, the coating on the edge, in the direction parallel to the vertical edge, extends (or protrudes) a minimum of about 0.0127 cm (5 mils) beyond the edge and beyond the plane of the face or alternatively , beyond the corner plane on the surface of the vertical edge, to give an even better seal; an even more preferred minimum is at least 0.0381 cm (15 mils) beyond either one of the corner plane or alternatively, beyond the facial plane. Prominent coatings, such as these (see Figure 5 and Figure 6) will improve the sealing ability. The coating may protrude beyond the plane of the joint face on one or both sides of the joint or beyond the corner on one or both sides of the edge. Preferably, it extends beyond the plane on both sides. The thickness of the coating in the direction perpendicular to the vertical edge is not critical. The coating is preferably a minimum of at least about 0.1 mm thick and preferably can be up to about 2 mm thick. The coating on the vertical edge is designed to seal the joint; thus, the coating must have a minimum thickness necessary to seal the joint. Suitably, the sealing coating on the vertical edge should be at least about 0.0025 cm (1 mil) thick (extending in a direction perpendicular to the vertical edge). In other modalities, the edge covering (coating A) is applied over the edges to be sealed, as in figure 7 (especially against fluids) and the rest of the joint is left completely uncoated, except for an optional release coating, such as a polymer coating containing fluoropolymer. Thus, in such embodiments, no coating strip is added as a border around the opening and which is joined to the coated vertical edge. The edge-coated gasket (coating A) is preferred for gasket applications where the gasket must withstand high flange or flange pressures, eg, greater than approximately 10,000 psi or in the range from approximately 703 Kg / cm2 (10,000 psi) to approximately 2109 Kg / cm2 (30,000 psi) where resistance to compression failure is particularly important. This limitation is significant, since it has been found that even the covering (B) of a border strip around the circumference of the opening adversely affects the performance of the joint, especially when the pressures are greater than about 703 Kg / cm2 (10,000 psi) (note seal sample C of Example 1). Thus, when a joint has a coating strip on one or both sides, the joint can preferably be used at pressures in the range of about 2109 Kg / cm2 (3,000 psi) to about 1054 Kg / cm2 (15,000 psi) and is even more preferred for use at pressures up to about 1054 Kg / cm2i5,000 psi). Particular types of joints, which are highly suitable for sealing at the edge, by coating the edge of the joint openings, include gaskets for compressors, for front covers, for block joints in diesel and automotive engines, flanges or flanges of tubes and pressure vessels. Such gaskets are highly charged and preferably such gaskets are coated on the edge, but they are not substantially coated on the facial surfaces in such a manner that they have sealing capability. Gaskets having optimized resistance to compression failures can be put into operation preferably at pressures in the range of about 1.4 Kg / cm2 (20 psi) or preferably from about 70.3 Kg / cm2 (1,000 psi) to about 2109 Kg / cm2 (30,000 psi). The resistance to compression failures will be better where less coatings are used. Joints with up to about 50% of the coated faces can be put into operation preferably in the range of about 210.9 Kg / cm2 (3,000 psi) to about 1054 Kg / cm2 (15,000 psi). Compression failure resistance will be better in a joint that has no coating or less coating than if the joint itself had at least a portion of the facial surface or a larger portion of the coated facial surface.

In another embodiment, the coating A can be superimposed on the corner of the joint edge and superimposed on either or both of the joint faces. The overlap on the face of the joint may fluctuate from a trace, less than 0.0025 cm (1 mil) or may extend to the formation of coating B. When it is desired that the A coating extend over the face of the joint and converting to coating B, the coating a is suitably extended to at least about 0.0127 cm (5 mils) on the face of the joint. More preferably, the overlap on the face extends over the face at a distance of 0.0254 cm (10 mils) or more, although it may be preferable that it be extended to form the B coating at a distance of 1.5 cm while does not cover more than about 50% of the joint surfaces. In other embodiments, the outer edge of the joint may be given a coating (coating C). In such a case, the outer edge of the joint material is perpendicular to the facial surfaces and is present around the joint as a circumference. The coating C is thus on the edge at the perimeter of the joint sheet. This outer edge is 'spliced' with all the outer corners of each facial surface. The covering C preferably covers the entire outer edge. However, such a coating is only a secondary seal against fluids, which enter mainly through the joint or over the joint, beyond the edge of the opening. It is preferred to coat the edge of the opening in place of, or in addition to the outer edge covering. A coating is any material which applies a coating. These include powders, filled polymers and 100% solid fluids. Can be used inorganic materials to coat the edge (to form any of the coatings A, B and / or C) which include chemically delaminated mica and vermiculite coatings. Preferred coatings are polymers (in which organic and inorganic hybrids and inorganic / organic hybrids are included), as well as filled polymers. The polymer coatings can be used to form either the coating A, the coating B or the coating C. Appropriately, the polymer coating materials are coatings selected from the group consisting of acrylic, acrylonitrile, acrylonitrile butadiene rubber (NBR) , fluoropolymers, hydrogenated NBR, styrene-butadiene polymer, fluoroelastomer polymer, acrylic-acrylonitrile polymer; carboxylated acrylonitrile polymer, carboxylated styrene-butadiene polymer, polyvinylidene chloride, chloroprene rubber polymer, ethylene propylene rubber polymer, ethylene / vinyl acetate polymer, epoxy, fluorosilicones, polyurethane and silicone rubber coatings (curable by UV light and curable at room temperature) and mixtures thereof can be used. A preferred polymeric coating is a filled polymer having silica, carbon black and / or clay filler. Any latex can be used. Any elastomer can be used. Also suitable as a coating are the polymeric powders which are heated to melt them on the surface of the joint. In effect, any powder which can be melted can be used to coat and seal the edge. The polymer coatings A, B and C can be different polymer coatings or they can be the same polymer coating. Since the coating of the faces of the soft joint for sealing capacity is limited, the performance of the joint under high pressure conditions (a minimum of at least approximately 210.9 Kg / cm2 (3,000 psi)) is maximized. At the same time, the vertical edge of the gasket opening has a coating to provide the gasket with an adequate sealing capacity. For the manufacture of the gaskets of the present invention, the edge of the joint can be coated in any convenient way. This is done either before or after coating B which can optionally be added to one or both sides of the joint. The present invention can be better understood from the following examples. However, these examples are included to illustrate the invention and not to limit it. All parts and percentages are by weight, unless otherwise indicated.

EXAMPLES Example 1 A. Compression test - ASTM F1574-95 Identical annular gaskets are cut from a cellulose-based paper gasket sheet material. Each joint formed a circle and had the following measures: internal diameter 1.3081 cm (0.515 inches), (distance from the center to the inner edge of the ring), external diameter: 2.413 cm (0.950 inches), ring width 0.5524 cm (0.2175 inches) ). The seal rings To which are indicated in Table 1 hereinafter, such as the control, were left completely uncoated; in B, each joint ring sample had the inner vertical edge (1.3081 cm (.515 inches) from the center) coated with NBR latex for joint samples C, the joint ring had the inner vertical edge coated with the latex of NBR and had a vulcanizable silicone coating strip at room temperature (from Loctite Corp.) coated on each face of the joint. This covering strip is placed on each face, in such a way that the covering strip comes into contact with the coating on the vertical edge. The coating strip is 0.0102 cm (4 mils) thick and 0.3175 cm (1/8 inch) wide. The joint samples D have a silicone coating coating vulcanizable at room temperature (from Loctite COrp.) Over the entire surface of the joint. To test the compressive strength at elevated temperatures, each joint ring was placed under a controlled pressure amount, at a temperature of 149 ° C (300 ° F) under uniform loading conditions and the deformation of the sample was measured as the percent change (increase) in area. This is a common test of the joints, known as the compression test and its description can be found in ASTM: F1574-95. The results of this comparison are given in Table 1 below. In the table, the values of each pressure level for each type of joint are given in terms of percentages of change in the area. It is considered a failure when the value is greater than 10. The higher the number, the worse the performance and the more undesirable the board is.

Table 1 Pressure Pressure (psi) A B C D (Kg / cm2) 175.75 2500 - - - 2 228.5 3250 - - - 21 351.5 5000 1 1 1 60 703 10,000 2 1 9 - 1054.5 15,000 2 4 35 _ The above data shows that the coated joint (D) can not withstand pressures of even 228.5 Kg / cm2 (3250 psi) without distorting to an undesirable degree. The performance of the uncoated joint (A) and the joint which is coated on the edge (B) and coated on the edge with a covering strip around the opening (c) shows much better performance and a capacity for to withstand even higher pressures of 1054.5 Kg / cm2 (15,000 psi) without significant distortion (less than 10% change in area). Seals C having the edge coating and the coating strip on the surface of that test are preferred for flange pressures of up to 10,000 psi (703 Kg / cm2).

B. Sealing capacity test They were cut together from a cellulose-based paper gasket sheet material. The joints tested were joint A (uncoated), joint B which had the inner vertical edge of the opening coated with NBR latex, for joint samples C the joint ring had the inner vertical edge of the opening covered with the NBR latex and had a vulcanizable silicone coating strip at room temperature (from Loctite Corp.) coated on each side of the joint (the strip on each side of the joint was 0.4762 cm (3/16 inch) wide) . These joint samples were placed in a cylinder which could be pressurized with nitrogen. For this test, the nitrogen pressure in the cylinder was brought up to 0.98 Kg / cm2 (14 pounds per square inch) and the number of minutes elapsed is measured while the pressure decreases to 0.914 Kg / cm2 (13 psi). This test is performed on a smooth flange or flange, which measures 18 Ra (Ra is the roughness value or average roughness and this is measured in micro-inches, MS indicates micro-pulses) and the test was also performed on a rough rim that measures 250 Ra . The results are given in table 2 below.

Table 2 Board Time (min) Flange Pressure Rough Pressure Gasket Time (minutes) Flange pressure Flange roughness A 1. 5 147.6 Kg / cm2 2100 PSI 18 Ra A 1. 0 147.6 Kg / cm2 2100 PSI 250 Ra B 11. 0 147.6 Kg / cm2 2100 PSI 18 Ra B 11. 0 147.6 Kg / cm2 2100 PSI 250 Ra C Total seal 21.1 Kg / cm2 300 PSI 18 Ra C Total seal 21.1 Kg / cm2 300 PSI 250 Ra Significantly, where the joint was sealed at the vertical edge of the opening and a coating strip was also provided on each face, the joint could give a perfect seal at a flange pressure as low as 21 Kg / cm2 ( 300 psi), over the smooth flange and the rough flange. In applications where sealing ability is important, therefore, the most preferred embodiment of the present invention has an edge seal coating and a coating strip on at least one face of the seal around the opening, to cover up to about 50% of the face of the board. Even more preferably, up to about 30% of each face of the joint can be coated.

Example 2 The effectiveness of the coating on the vertical edge of the joint, to provide a good seal capacity for the joint, is demonstrated by the data of this example. Identical seals were obtained from the same laminar seal material. Both joints had two parallel faces with a vertical edge around a circular opening. Joint A is allowed to remain completely uncoated. However, a NBR (Reichhold) latex coating is applied to joint B on the vertical edge of the joint which formed the opening. For this example, only the vertical edge was coated. The sealing capacity of each of these joints is demonstrated in a high-pressure seal capacity test. According to this test a gasket is retained in place to seal a nitrogen cylinder. The nitrogen is pressurized to 15.8 Kg / cm2 (225 pounds per square inch). The flange which the seal seals is placed under pressures at recorded levels. The cylinder is allowed to sit for one hour and the pressure of the remaining gas is noted at the end of the hour. The best seal will maintain the highest gas pressure.

Table 3 Gasket Flange pressure 35.1 Kg / cm2 70.3 K / cm2 500 psi 1000 psi A (uncoated) much leakage much leakage B (coated) 15.3 Kg / cm2 15.7 cm2 218 psi 223 psi Board A, uncoated, had a leak so large that it was impossible to note the gas pressure after one hour had elapsed. The above data also shows that by coating the vertical edge around the circumference of the opening, that joint can be given a substantial sealing capability. It is seen that even at the flange or flange pressure lower than 35 Kg / cm2 (500 psi), the edge-coated gasket retains the gas pressure at 15 Kg / cm2 (218 psi) after one hour.

EXAMPLE 3 The seal sheet material used in Example 2 was used to provide seal rings which were subjected to the compression test described in Example 1. The seal A, the control or reference, is left uncoated and is not Seal on the edge. The gasket B is provided with a coating on the vertical edge which forms the opening in the center of the gasket ring. Each joint ring is subjected to a pressure of 351.5 Kg / cm2 (5,000 psi) before the deformation is seen. The results in table 4 below show the percent change in area under each pressure level.

Table 4 Board 351.5 Kg / cm2 703 Kg / cm2 1054.5 Kg / cm2 Board 351.5 Kg / cm2 (500 psi) 703 Kg / cm2 (10,000 psi) 1054.5 Kg / cm2 (15,000 psi) A (uncoated) 1 10 16 B ( coated edge) 2 9 61 Example 4 This test simulates a deformed or warped flange.

The test shows that joint C, which has the vertical edge sealed and the coating strip on each side of the joint around the opening, still provides a good performance. For the test, the flange used had a concave surface. The concavity, dispersed over the width of the rim, was 36 mm long and 0.0076 cm (3 mils) deep at the center point. The cylinder is equipped with a gasket and 17.5 Newton-meters of torque are applied to each of the two bolts. The oil fills the cylinder and an air pressure of 0.35 Kg / cm2 (5 psi) is applied to the oil. The joint is considered to fail if the oil penetrates 2/3 of the joint width after 46 hours. For the uncoated gasket (gasket A) there were failures. The oil had completely penetrated through the outer edge of the joint after only five hours. For joint C (which has the vertical edge coated with coating strips on each face), there was no oil penetration to the joint after 46 hours.

Example 5 An annular gasket identical to that used in example 1 was cut from the same gasket material as that used for Example 1. An acrylic latex (from BASF) is used to coat the seal ring sample on the gasket. internal vertical edge of the ring opening. The coating is applied on the vertical edge in such a way that in the direction from one side of the vertical edge to the other, parallel to the vertical edge of the joint, the coating was thicker than the thickness of the joint. In addition, the coating gradually increases in width of thickness (in a direction parallel to the edge of the joint) as the distance of the vertical edge increases. The coating on the edge of the joint, in effect, resembles Figure 5. The distance from the center of the vertical edge of the gasket to the end of the coating was measured at about 0.9 mm. The thickness of the joint (and the vertical edge thickness) was approximately 0.0813 cm (32 mils). Measuring the coating at its widest point, the coating measured approximately 0.0686 cm (27 mils) beyond each corner of the vertical edge where the edge joined the face of the joint. In other words, since the partial planes of each side of the joint through the corner of each cut, the vertical edge, (the vertical plane and the facial plane are the same plane) the coating, at its widest point it was also approximately 0.0686 cm (27 mils), beyond the plane on each side of the joint (measured between the plane and the joint of the coating). The joint was tested in a cylinder which could be pressurized with nitrogen (as described in example 1). The nitrogen pressure in the cylinder was brought up to 0.98 Kg / cm2 (14 psi) and the number of minutes is measured which passes while the pressure decreases to 0.91 Kg / cm2 (13 psi). This test is carried out on a smooth flange measuring 18 Ra. The control of this test is the reported result for joint A of example 1, which retained the pressure for only 1.5 minutes and required a flange pressure of 147.6 Kg / cm2 (2100 psi). The seal at the edge of this example provides a total seal (the pressure never decreases in the cylinder) and the pressure of the cylinder flange on the joint was only 21 Kg / cm2 (300 psi). Accordingly, a perfect seal is obtained by coating the particular edge of this example. In applications where the sealing capacity and resistance to compression failures are important, therefore, it will be advantageous to use an edge covering where the coating is wider than the vertical edge of the joint (in a direction parallel to the edge). vertical).

Example 6 An annular gasket identical to those used in example 1 was cut from the same gasket material as that used in example 1. A silicone coating is used to coat the sample in the gasket ring on the inner vertical edge of the opening of the ring. The coating is applied on the vertical edge, such that in a direction parallel to the vertical edge of the joint, the coating was thicker than the thickness of the joint close to the vertical edge of the joint and the coating overlaps or overlaps a horizontal face of the board (as shown by figure 6). From the vertical edge of the joint through the coating in a direction perpendicular to the vertical edge, it is measured that the coating is approximately 0.4 mm in the center of the vertical edge. The joint was tested in a cylinder which could be pressurized with nitrogen (as described in example 1). The nitrogen pressure in the cylinder was brought up to 0.98 Kg / cm2 (14 psi) and if the flange does not have a total seal at a given flange pressure, the number of minutes is measured, while the pressure decreases to 0.91 Kg / cm2 (13 psi). The lower the flange pressure at which a total seal is obtained, the results are better and if you can not obtain a total seal at any flange pressure, the pressure is maintained longer and the result is better. This test is carried out on a smooth flange measuring 18 Ra. The control of this test is the reported result for joint A of example 1, which maintains the pressure only for 1.5 minutes and requires a flange pressure of 147.6 Kg / cm2 (2100 psi). The sealed edge joint of this example provides a total seal (the pressure never decreases in the cylinder) at the flange pressure of 147.6 Kg / cm2 (2100 psi).

Example 7 An annular gasket identical to that used in example 1 was cut from the same gasket material as that used for example 1. A silicone coating is used to coat the seal ring sample on the inner vertical edge of the gasket. the opening of the ring. The coating is applied on the vertical edge, such that in a direction parallel to the vertical edge of the joint, the coating was thicker than the thickness of the joint close to the vertical edge of the joint and the coating is superposed on each side. horizontal face of the board (as shown by figure 8). The coating extends on each horizontal face of the joint by a distance which was measured at approximately 0.38 mm. The joint was tested in a cylinder which could be pressurized with nitrogen (as described in example 1). The nitrogen pressure in the cylinder was brought up to 0.98 Kg / cm2 (14 psi) and if the flange does not have a total seal at a given flange pressure, the number of minutes is measured, while the pressure decreases to 0.91 Kg / cm2 (13 psi). The lower the flange pressure at which a total seal is obtained, the better the results and if a full seal can not be obtained at any flange pressure, the pressure is maintained longer and the result is better. This test is performed on a smooth flange that measures 18 Ra. The control of this test is the reported result for joint A of example 1, which maintains the pressure only for 1.5 minutes and requires a flange pressure of 147.6 Kg / cm2 (2100 psi). The seal at the edge of this example provides a total seal (the pressure never decreases in the cylinder) at the flange pressure of only 21 Kg / cm2 (300 psi).

Example 8 It has been found that coatings which are provided to a joint, which function to increase the seal capacity at the joint, damage the joint resistance to faults under pressure (resistance to compression failure). Further, even when a sealing coating strip is applied on the face of the gasket, even if the coating covers less than 30% of the gasket face (in a preferred embodiment), the resistance to gasket failures. compression is adversely affected. Thus, it is important to limit the amount of coating for the sealing capacity on the face of the joint. This example is added to demonstrate the effect of the coating for the sealing capacity on the resistance to compression failures. This example demonstrates the need to limit the width and thickness of the sealing coating placed on the face of the gasket, this example also demonstrates that the most preferred gasket for resistance to compression failures has an edge seal with substantially none of the gasket. coating of the seal on the face of the joint. When there is substantially no sealing coating that is coated on the face (some amount can be found at the edges) there will be substantially no effect on the resistance to compression failures. This is seen by comparing the results of sample A and sample B of the table below. At all pressure levels, the performance of sample B was comparable to the performance of sample A even at high pressure levels. To demonstrate the effects of edge coating and face coating provided near the vertical edge of the joint, identical annular seal rings were cut and provided with the different coatings indicated below. No coating is provided to the reference or control. The measurements for the joints are the same as indicated for the joints given in the compression test in example 1. The resistance to compression failure at the temperature of 149 ° C (300 ° F) is tested for each of the boards. The proof, known as the compression test is described in the ASTM: F1574-95. The deformation of each joint is indicated under the indicated pressure load (as a percentage). The higher the number for each given pressure load, the more deformation there is and the performance of the joint is worse. Sample A - where the control or reference joints have no coating. Sample B - has only one edge seal, substantially without any coating applied on either side of the joint. The coating on the edge of the joint, in effect, resembles the preferred embodiment of Figure 5. Sample C - has a coating on part of each side of the joint. The coating on each face is 0.008 cm (3.2 thousandths of an inch) - 0.0107 cm (4.2 thousandths of an inch) thick and 0.2337 cm (92 thousandths of an inch) wide on the face, which begins at the vertical edge (which it was not coated). Sample D - has a coating on part of each face of the joint. The coating on each face is 0.0020 cm (0.8 mil) - 0.0030 cm (1.2 mil) thick and 0.2337 cm (92 mil) wide on the face that begins at the vertical edge (which does not was coated) and through the face of the board.

Sample E - has a coating on part of each face of the joint. The coating on each face is 0.0081 cm (3.2 thousandths of an inch) - 0.01067 cm (4.2 thousandths of an inch) thick and 0.4775 cm (188 thousandths of an inch) wide on the face that begins at the vertical edge (which does not it was coated) and through the board. Sample F - has a coating on each side of the joint. The coating on each face is 0.0020 cm (0.8 mils) - 0.0030 cm (1.2 mils) thick and 0.4775 cm (188 mils) wide on the face that begins at the vertical edge (which it was not coated) and through the board. Sample G - has a coating on each side of the joint. The coating on each face is 0.0081 cm (3.2 thousandths of an inch) - 0.01067 cm (4.2 thousandths of an inch) thick and 0.7163 cm (282 thousandths of an inch) wide on the face that begins at the vertical edge (which does not it was coated) and through the board. Sample H - has a coating on each side of the joint. The coating on each face is 0.0020 cm (0.8 mil) - 0.0030 cm (1.2 mil) thick and 0.7163 cm (282 mil) wide on the face that begins at the vertical edge (which does not it was coated) and through the board.

Sample I - has a release coating on each side of the joint. The coating on each face is less than 0.0025 cm (1 mil) thick and covers the entire joint. The data in the table below confirm that the narrowest band of the coating applied on the face of the joint had a better resistance to compression failure than a wider coating band. The thickness of the coating on the face also affects the resistance to compression failures. Indeed, it can be noticed that, as the thickness advances from 0.0020 cm (0.8 thousandths of an inch) - 0.0030 cm (1.2 thousandths of an inch, at 0.0081 cm (3.2 thousandths of an inch) - 0.01067 cm (4.2 thousandths of an inch) in Samples G and H, there is a larger effect and a greater impact on resistance to compression failures (to give a better resistance to compression failures with the thicker coating) than that between samples D and H (samples that have the width that is varied but with the same thickness). Thus, it is even more important to limit the thickness of the coating on the face of the joint. The data in the table below also confirms that the release coating on Sample I has substantially no effect on the compression failure of the joint. Thus, release coatings (generally less than about 0.0025 cm (1 mil) in thickness, are allowed on one side of the joint and the compressive failure resistance is good to excellent and is not detrimentally affected.

Table 5 Sample 527 Kg / cm2 703 Kg / cm2 878.7 Kg / cm2 1054.5 Kg / cm2 1406 Kg / cm2 (7500 psi) (10000 psi) (12500 psi) '(15000 psi) (20000 psi) A 1.5 1.54 2.13 2.20 2.20 4.38 B 2.13 2.33 3.53 3.59 4.57 C 3.76 5.42 6.28 9.53 19.51 D 2.47 3.59 3.73 6.84 14.51 E 8.82 14.32 16.85 28.01 42.98 F 2.35 5.98 7.79 15.49 35.00 G 12.76 20.84 33.72 41.50 100.00 H 1.98 5.62 12.26 31.81 43.66 I 0.56 1.03 1.60 3.16 3.54 In the above table, the load on each individual joint sample is indicated in Kg / cm2 (pounds per square inch). The numbers listed under each pressure level for each of the joint samples show the percent increase in the joint area after the face was released. The smaller the percent increase, the better the performance of the board.

The small percent increase for the coated I-sample release test shows that a release coating less than 0.0025 cm (one thousandth of an inch) thick does not have any detrimental effect on the compressive strength. Indeed, the global data confirms that the gaskets of the present invention can provide a good seal and good compressive strength. It is noted that, with regard to this date, the best method known to the applicant, to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following

Claims (40)

1. Claims 1. A gasket characterized in that it comprises a soft material having two opposite facial surfaces and an edge surface, the edge surface is around an opening in the soft material, the edge is substantially perpendicular to the facial surfaces, the edge it also has a coating A on the edge, to provide the joint with a good sealing ability, which further achieves that the facial surfaces of the joint are not substantially coated, to obtain sealing capacity and the joint is more resistant to failure by compression that the same gasket would be with a sealing coating over at least a portion of at least one facial surface.
2. 2. The board in accordance with the claim 1, characterized in that it can be put into operation either: i) at pressures in the range of about 703 Kg / cm2 (10,000 pounds per square inch) to about 1209 Kg / cm2 (30,000 pounds per square inch) or ii) at pressures in the range of approximately 1.4 Kg / cm2 (20 pounds per square inch) to approximately 2109 Kg / cm2 (30,000 pounds per square inch).
3. The gasket according to claim 1, characterized in that the gasket material has an edge which is substantially perpendicular to the facial surfaces and is present around the gasket as a circumference and is located on all the outer edges of each surface Facial, where the outer edge has a coating C over the edge.
4. 4. The board in accordance with the claim 1, characterized in that the edge is completely covered with the coating A.
5. 5. The gasket according to claim 1, characterized in that it is for either: i) a front cover for gaskets of the block in a diesel or automotive engine, ii ) a pipe flange or flange, 3) a pressure vessel, or 4) a compressor.
6. The gasket according to claim 1, characterized in that the coating A is wider than the edge of the gasket, at the edge of the gasket in a direction parallel to the edge, such that the coating projects beyond a gasket. corner which falls between the edge and one of the facial surfaces.
7. The gasket according to claim 1, characterized in that the coating A is a polymer.
8. The gasket according to claim 7, characterized in that the polymer is selected from the group consisting of acrylic, acrylonitrile, acrylonitrile butadiene rubber, fluoropolymers, hydrogenated acrylonitrile butadiene rubber, styrene butadiene polymer, fluoroelastomer polymer, polymers of acrylic-acrylonitrile, carboxylated acrylonitrile polymer, carboxylated styrene butadiene polymer, polyvinylidene chloride, chloroprene rubber polymer, ethylene propylene rubber polymer, ethylene / vinyl acetate polymer, epoxy, fluorosilicones, polyurethane and rubber coatings silicone and mixtures thereof.
9. The gasket according to claim 1, characterized in that the coating A is a latex.
10. The gasket according to claim 1, characterized in that the coating A is a powder melted on the edge.
11. The gasket according to claim 1, characterized in that the gasket has a release coating on each side of the gasket.
12. 12. A gasket characterized in that it comprises two substantially opposite facial surfaces and a surface of the rim around an opening in the gasket, the surface of the rim being substantially perpendicular to the facial surfaces, the surface of the rim also has a coating A, which is a coating on the surface of the edge, at least one of the facial surfaces has a coating for a sealing capacity, which also has surface areas which are not coated with the coating, to obtain a sealing capacity in an effective amount for provide the board with better resistance to compression failure that the same board would have with the coating to obtain a sealing capacity on at least some part of the surface, which is not covered to obtain sealing capacity.
13. The gasket according to claim 12, characterized in that it also comprises a soft gasket material.
14. The gasket according to claim 12, characterized in that it is a gasket for either: i) an intake manifold, ii) an oil pan, ii) a valve cover, iv) an axle cover, v) a compressor, vi) a water pump, vii) a pipe fitting, vii) an oil cooler for a diesel engine, ix) a gas meter or x) a pressure vessel.
15. The gasket according to claim 12, characterized in that at least one of the opposite facial surfaces has a coating, which covers approximately 50% or less of the opposite facial surface.
16. 16. The gasket according to claim 12, characterized in that the coating on the opposite facial surface is the coating B, which is a coating that passes around the opening and splices to the edge and joins the coating A.
17. 17. The gasket according to claim 12, characterized in that the coating on the opposite facial surface has a maximum thickness of approximately 0.0279 cm (11 mils).
18. 18. The gasket according to claim 16, characterized in that the coating B has a maximum width on the facial surface of 1.5 centimeters.
19. 19. The board in accordance with the claim 12, characterized in that, in addition, the joint material has an outer edge which is substantially perpendicular to the facial surfaces and is present around the joint as a circumference and is located on all the outer edges of each facial surface, wherein the The outer edge has the coating C.
20. 20. The gasket according to claim 12, characterized in that the coating A is wider than the edge of the gasket at the edge of the gasket in a direction parallel to the edge, such that Coating protrudes beyond at least one corner which falls between the edge and one of the facial surfaces.
21. 21. The gasket according to claim 12, characterized in that it is used at flange pressures in the range of about 1.4 kg / cm2 (20 pounds per square inch) to about 2109 kg / cm2 (30,000 pounds per square inch).
22. The gasket according to claim 12, characterized in that the edge of the opening is completely covered with the coating A.
23. 23. The gasket according to claim 12, characterized in that the covering for the edge of the opening, the coating A is a latex
24. 24. The board in accordance with the claim 12, characterized in that the coating for the edge of the opening, the coating A is a polymer.
25. 25. The gasket according to claim 24, characterized in that the polymer is selected from the group consisting of: acrylic, acrylonitrile, acrylonitrile butadiene rubber, fluoropolymers, hydrogenated acrylonitrile butadiene rubber, styrene butadiene polymer, fluoroelastomer polymer, polymers acrylic-acrylonitrile, carboxylated acrylonitrile polymer, carboxylated styrene butadiene polymer, polyvinylidene chloride, chloroprene rubber polymer, ethylene propylene rubber polymer, ethylene / vinyl acetate polymer, epoxy, fluorosilicones, polyurethane and rubber coatings of silicone and mixtures thereof.
26. 26. The gasket according to claim 15, characterized in that it is used for flange pressures in the range of about 703 Kg / cm2 (10,000 pounds / square inch) to about 2109 Kg / cm2 (30,000 pounds / square inch).
27. 27. The gasket according to claim 12, characterized in that the edge of the opening has pores and the coating A has penetrated the pores.
28. The gasket according to claim 12, characterized in that it also has hole areas for bolts wherein the bolt hole areas are the surface areas that are not coated.
29. 29. The gasket according to claim 12, characterized in that the coating for obtaining the sealing capacity is limited to a maximum thickness of approximately 0.0279 cm (11 mils) only in the areas of bolt holes.
30. 30. A gasket characterized in that it comprises: a sheet or base sheet of porous material having two substantially parallel, opposite faces and at least one edge disposed therebetween; and a coating disposed on and substantially coextensive with the edge, the coating is effective to give the base sheet a seal against the passage of fluids through the edge, wherein the faces of the sheet or base sheet have substantially no coating for the seal of the joint against fluids.
31. 31. The gasket according to claim 30, characterized in that the coating is the coating C on the edge of the gasket, which forms the perimeter on the outside of the faces of the gasket.
32. 32. A process for improving the sealing of a soft gasket sheet or sheet having two substantially opposite facial faces and an opening with an edge perpendicular to the facial surfaces, which consists essentially of covering the edge perpendicular to the facial surfaces in an amount effective to obtain a substantial seal of the joint along the perpendicular edge of the opening.
33. 33. The process according to claim 32, characterized in that it further comprises coating at least one of the opposing facial surfaces with a coating that covers approximately 50% or less of the facial surface.
34. 34. The process according to claim 32, characterized in that it provides up to 75% of the coated perpendicular edge.
35. 35. The process according to claim 33, characterized in that it further comprises covering at least one of the opposing facial surfaces with the coating B, which is a coating that is connected to the opening and extending to approximately 1.5 centimeters from the opening through the opposite facial surface.
36. 36. The process according to claim 35, characterized in that the coating B has a maximum thickness of approximately 0.0279 cm (11 mils).
37. 37. A process for applying a coating on a perforated edge of a sheet or sheet of soft joint, wherein the sheet or sheet of the joint has two substantially opposite facial faces and an opening with the edge substantially perpendicular to the facial surfaces, characterized in that it comprises placing together a plurality of the joint sheets, in such a way that a cavity is formed by each opening of the plurality of joint sheets and contacting the edges of the opening on each joint sheet with a coating material , such that the edges are coated in an effective amount to obtain a substantial seal of the seal along the edge of the opening where the edge is coated.
38. 38. The process according to claim 37, characterized in that only a portion of each edge of the opening on the board sheet is brought into contact with the coating material.
39. 39. The process according to claim 37, characterized in that the entire edge of the opening in each joint sheet is brought into contact with the coating material, such that the entire edge is coated.
40. 40. The process according to claim 37, characterized in that at least one cavity is formed by the plurality of seal sheets, each of the sheets having an opening that is substantially identical to the openings of the other seal sheets, wherein the identical openings of the plurality together form the cavity.