Abstract: A sports board has a hard top shell formed with a top concave shell cavity. The hard top shell has an inside surface. The hard top shell is pervious to light. A top layer of adhesive adheres to the hard top shell. A rigid foam core is formed with a top profile and a bottom profile. The top profile matches and receives the top hard shell. The top layer of adhesive adheres to a top surface of the foam core. A bottom layer of adhesive adheres to a bottom surface of the rigid foam core; and a hard bottom shell is formed with a bottom concave shell cavity. The bottom concave shell cavity is formed to fit to the bottom profile. The hard bottom shell is pervious to light.

Abstract: A snap in weatherstripping where the backing has a plurality of alternating notched out spaces along each side to facilitate ease of insertion into a channel without the need to slide the weatherstripping longitudinally into the channel. The snap in weatherstripping can be pushed into the channel with a gentle side to side or rolling motion, thus eliminating the difficulties associated with longitudinally sliding a weatherstripping into a channel. The snap in arrangement of the weatherstripping eases replacement, and also accommodates variations in tolerance between the weatherstripping and the channel, making it desirable for replacement of existing degraded weatherstripping.

Abstract: The present invention is directed to a method of forming a molded core component. A mat formed from cellulosic fiber and resin is provided. The mat is consolidated in a first press until the resin is substantially fully cured, and then removed from the first press. The consolidated mat is then placed in a second press having a mold cavity shaped to form at least one depression in at least one of the major surfaces. The consolidated mat is reformed in the second press to form a molded core component having at least one depression in at least one of the major surfaces. The molded core component has a variable density, preferably of between about 10 lbs/ft3 and 80 lbs/ft3.

Abstract: A protective pad configuration is provided that includes a corrugated energy dispersing plate disposed between an upper and a lower foam member. The corrugated energy dispersing plate provides stiffness along a first direction and flexibility in a second direction to enable pad design that maximizes both athlete protection and mobility.

Abstract: The present invention provides methods for adding a polymer form to a fixture such as a bathtub, shower stall, sink, or toilet, and those articles. The polymer form comprises a rigid foam and a topcoat. The polymer form, in some embodiments, imparts improved performance characteristics such as temperature retention, sound deadening, and rigidity, and can allow a steel fixture to better mimic one made of cast iron at significantly less expense. The fixtures include metal fixtures with and without enamel coatings.

Abstract: The invention relates to a method for producing a form-cut object made of foam. The invention is is based on the aim of refining a known method for producing a form-cut object made of foam in that it also allows the precise creation of complex shaped form cuts in the foam. This aim is achieved by the method according to the invention in that the first preliminary version of the object in the region of a first form or contour cut is provided with a (second) form cut, which is superimposed on the first form or contour cut and extends down to larger depths than the first cut. Preferred application areas of the claimed method and the resultant objects made of foam are pillows, for example.

Abstract: The present invention is a method to manufacture shaped foam article. Specifically, the present invention is a method of extruding a styrenic polymer with a blowing agent to form a foam polymer plank having a density gradient and shaping the surface of the foam plank having the lowest density by passing the foam plank through one or more sets of rolls. Preferably, the foam has a vertical compressive balance (Rv) equal to or greater than 0.4 and more preferably, the foam has a cell gas pressure less than 1 atmosphere and/or an open cell content of equal to or less than 20 percent.

Abstract: A steel plate reinforcing sheet includes a restricting layer and a reinforcing layer, the reinforcing layer being formed of foam composition including styrene synthetic rubber, aromatic epoxy resin, and a foaming agent. A total thickness of the restricting layer and reinforcing layer is not more than 3.5 mm, and the steel plate reinforcing sheet is formed to have adhesion at 5° C. to an oiled, cold-rolled steel plate of not less than 2.0N/25 mm and also has bending strength of not less than 18N after being heated at 160° C. for twenty minutes. This ensures both sufficient adhesion to the steel plate and sufficient reinforcement of the same steel plate. Thus, this steel plate reinforcing plate, when adhesively bonded to a steel plate used in a variety of industrial machines properly and then foamed, can provide an effective reinforcement of the steel plate by forming the steel reinforcing plate bonded to the steel plate.

Abstract: A substrate for patterned application comprises: a substrate body having a patterning area (15A) and a non-patterning area (17A) surrounding the patterning area; a plurality of partitions (15) provided in stripes in the patterning area of the substrate body; and an ink retaining portion provided in the non-patterning area on one side and on the other side of the partitions in their longitudinal direction and being capable of retaining an applied liquid ink.

Abstract: Seal Guard Lip & Tape System provides users with an efficient means and method for applying underlay for various types of flooring. The system entails the joining of two laminate floor underlay sections to create a vapor barrier. The vapor barrier provides superior sealing by utilizing vapor barrier tape with release liner, and also reduces harm to installed flooring. Seal Guard Lip & Tape System may comprise foam underlay with vapor barrier qualities, vapor barrier tape, and release liner, all of which can be laminated together. The specially formulated vapor barrier tape can be attached to a 1½? release liner, which may be made of siliconized paper plastic, covering approximately half of the tape. The vapor barrier tape/release liner combination may be joined to the laminate underlay with 1½? of the tape and liner exposed beyond the foam underlay. The entire assembly can be easily affixed to an adjacent underlay sheet, thereby creating a sealing means.

Abstract: A sports mat includes a first foam layer, a second foam layer laminated on the first foam layer and a patterned laminate bonded on the second foam layer. The first and second foam layers are both made of polyethylene foam containing material of elastic resin and have a density in the range of 2 to 8 pcf and a total thickness in the range of 2 to 8 mm. In addition, the first foam layer is embossed therebottom with a plurality of elongated ridges parallel to one another. The patterned laminate includes a first plastic film laminated to the second foam layer, a second plastic film laminated to the first plastic film, and a pattern placed in between the first and second plastic films and visible through the second plastic film. Additionally, the pattern laminate together with the second foam layer is embossed to define a plurality of concaves in an exterior surface thereof.

Abstract: To achieve weight reduction while providing elasticity sufficient in a cushioning member for a vehicle seat, an elastic member made of expanded resin beads includes an elastic covering material having stretching properties stuck to an outer face of an expanded bead body. Therefore, when the elastic member made of expanded resin beads is bent or compressed, the respective beads themselves configuring the expanded bead body are elastically deformed according to stretching or compressing of the elastic covering material, and since the elastic deformation is not such deformation that a gap between beads of the expanded bead body largely expands, a crack occurring between beads or permanent deformation does not occur so that bending or compressing becomes possible. Accordingly, the elastic member made of expanded resin beads is suitable as a cushioning member utilizing an elastic recovering force in a bending direction and a thickness direction thereof.

Abstract: A decorative laminate (10) includes a polymer or engineered film with fluorine (100), a decorative pattern (20) visible through the polymer film (100), and a substrate (200) supporting the polymer film (100) and decorative pattern (20). An embossing layer (70) may be included between the polymer film (100) and substrate (200). The embossing layer (70) or substrate (200) or both may contain one or more fire retardant materials such as halogens. The decorative laminate (10) has a resistance to sustained ignition rated as at least M1 according to French Epiradiateur Test NFP 92-501, and a smoke index value of 80 or less, a classification of F3 or better according to French standard NF F-16-101 based on French Tests NF X 70-100 and NF X 10-702, and a resistance to graffiti in a range of G0-G1 as measured by French Graffiti test NF F 31-112.

Abstract: Continuous manufacture of at least a layer of latex foam with recesses of unlimited length to be divided in a plurality of blocks of latex foam by transverse cuts. The layer has a thickness between 10 and 20 cm and more. The process includes advancing along a predetermined longitudinal direction a metal laying surface provided with protuberances, gelating, curing. The process includes: a) Before depositing the latex foam inserting, by interference fit, supporting elements of resilient deformability having a predetermined thickness between pairs of protuberances of horizontal rows, the supporting elements of unlimited length; b) Carrying away the supporting elements with the advancing laying surface between an injection latex foam station and a layer extracting station; c) Embedding with latex foam the supporting elements. Advantageously the process forwards the blocks to a washing station and squeezes the blocks to a thickness reduction between 3% and 5% of their initial thickness.

Abstract: The invention relates to an improved method of cold forming a shaped foam article wherein the improvement is using a near net-shaped foam blank cut from a foam plank having a vertical compressive balance equal to or greater than 0.4 to produce the shaped foam article.

Abstract: A three-dimensional foaming type transfer paper with an enhanced durability and a method for manufacturing the same is disclosed. The transfer paper includes a releasing agent layer having a releasing sheet and formed on the releasing sheet using transparent silicon; a fluorine coating layer formed on the releasing agent layer; a silicon rubber layer formed only on a portion of the fluorine coating layer on which printing is to be performed, through a silk screen process; a first fluoride polyester layer formed on the silicon rubber layer; a printed layer formed on the first fluoride polyester layer using ink; a second fluoride polyester layer formed on the printed layer; a first foaming layer formed partially on the second fluoride polyester layer; a second foaming layer formed on the first foaming layer; and a thermal adhesive resin layer formed on the second foaming layer.

Abstract: Cushioning elements may include a first material layer, a second material layer, a plurality of components (e.g., polymer foam components) that are located between the first material layer and the second material layer. Some of the components are secured to the first material layer and the second material layer, and other components are unsecured to the first material layer and the second material layer. In some configurations, the various components have different thicknesses. In further configurations, at least one of the component defines a plurality of apertures that receive other components.

Abstract: A sports mat includes a foam sheet, an adhesive bonding film, a patterned layer and a skid proof layer. The foam sheet is made of polyethylene foam. The adhesive bonding film applied to a top surface of the foam sheet. The patterned layer has a plastic film and a pattern printed in a bottom surface of the plastic film. The plastic film together with the pattern is joined on top of the adhesive bonding film. The skid proof layer, made of thermal plastic rubber, is coated over a top surface of the plastic film. Additionally, the skid proof layer together with the patterned layer, the adhesive bonding film and the foam sheet defines a plurality of indentations and protrusions over a top surface of the skid proof layer so as to strengthen connection therebetween.

Abstract: An in-line process for forming pre-finished siding manufactured from cellular poly vinyl chloride comprising embossing, milling, parting, punching, and coating the poly vinyl chloride such that the resulting siding is suited for use in an environment exposed to a wide range of fluctuating temperatures and moisture. The process accommodates the natural expansion and contraction of cellular poly vinyl chloride by producing a novel milled clapboard configuration that, when used as siding, can be installed to create a historically correct clapboard installation.

Abstract: In one of its aspects, the invention relates to a foam element comprising an isocyanate-based foam matrix having surface, at least a portion of the surface comprising at least one channel having a channel surface, the channel surface being coated with a substantially fluid impermeable material. The foam element is particularly useful in a climate-control vehicular (e.g., automobile) seat.

Abstract: The invention provides methods for producing flexible, stretchable, and/or elastic products comprised principally of material such as natural elastomers and other synthetic polymers. The method for producing stretchable products by spraying product material over a workpiece former, and method for creating perforated products by spraying product material over fibres in an upright position. The invention provides methods for making double sided fibre coating of the product and, or to at least coating the product surface on the side facing the wall without the need for removing the product from the wall.

Abstract: A sheet including a coextruded medium made from at least one polymer material, including a core layer and at least one skin layer, the core layer including voids, the sheet having intaglio printing performed thereon.

Abstract: A bilaminate wrap and methods for its manufacture are disclosed, the wrap being useful for incorporation onto interior trim panels. The bilaminate wrap comprises a skin integrated with a foam layer made of a plastics material, most preferably a thermoplastic polyolefin. The plastics material permits thin constructions and the use of skiving to incorporate different profiles of variable thicknesses into the panels.

Abstract: A superabsorbent foam which comprises at least 1% by weight, based on the total weight of the dry foam, of inorganic pulverulent solid and bears graphics on at least one of its surfaces is obtainable by a process in which a foamed monomer mixture which comprises an appropriate amount of inorganic solid is polymerized in a mold which bears graphics on at least one inner surface.

Abstract: An anti-skid exercise mat includes a foam member having a predetermined thickness, a fabric layer located on at least one side of the foam member, and at least one soft plastic material disposed on a predetermined area of a surface of the fabric layer and at least penetrating into the fabric layer for a predetermined depth for scarf joint and adhesive connection with fibers of the fabric layer. Accordingly, the anti-skid exercise mat has preferable anti-skid and perspiration-absorptive functions during the whole course of exercising.

Abstract: A laminate web having a nonwoven web in facing relationship with a polymer film. The laminate web has a first side comprising the polymer film and a plurality of discrete tufts including fibers integral with and extending from the nonwoven web. Each of the tufts has a tuft base proximal to the nonwoven web and a distal portion opposing the tuft base. At least part of the distal portion of each of the tufts is covered by a cap, each cap being an integral extension of said polymer film extending over the distal portion of a discrete tuft. The cap has a first opening including a location of rupture in the polymer film above which the tuft extends.

Abstract: The invention aims to provide a protector that is prevented from being loosened from an electrochemical element, prevented from having dispersion in dimension and prevented from coming off the electrochemical element. In a protector 200 of an electrochemical element 100, that entirely covers an electrochemical element entirely covered with an aluminum laminate film 90, improvement is that the protector 200 has a recess 210, 220 that receives a wrinkled portion 92 of the aluminum laminate film 90, the wrinkled portion 92 being formed at a corner portion of the electrochemical element 100. Thus, when it is intended to mount the protector 200 to the electrochemical element 100, the wrinkled portion 92 of the aluminum laminate film 90 is received into the recess 210, 220 that is to say, the recess 210, 220 serves as a relief for the wrinkled portion 92. Thus, the protector 200 can be intimately connected to the electrochemical element 100.

Abstract: A vibration-reducing material, comprising first and second elastomer layers and a reinforcement layer disposed between and generally separating the first and second elastomer layers. The reinforcement layer comprises a high tensile strength fibrous material. At least one of the first or second elastomer layers is manufactured as a foamed structure.

Abstract: A floor mat and a method of making the floor mat are provided. The method may include forming a foam polyvinyl chloride body of a floor mat. The body may be embossed to form one or more thicker and thinner regions of the body. Moreover the thicker and thinner regions may be arranged to define panels and folding lines of the body such that the panels are foldable relative to each other. In some embodiments, the body may include a plurality of fold lines between adjacent panels to allow for a large folding radius. Other operations of the method may include embroidering a design onto the body or attaching a fabric layer to a top surface of the body of the floor mat.

Abstract: Embodiments disclosed in the detailed description include a unitary or monolithic composite or hybrid cushioning structure(s) and profile(s) comprised of a cellular thermoplastic foam and a thermoset material. The thermoset material may also be provided as cellular foam as well. In one embodiment disclosed herein, the unitary composite cushioning structure is formed from a cellular thermoplastic foam and a thermoset material. The cellular thermoplastic foam provides support characteristics to the unitary composite cushioning structure. The thermoset material provides a resilient structure with cushioning characteristics to the cushioning structure. A stratum is disposed between at least a portion of the cellular thermoplastic foam and at least a portion of the thermoset material to secure the at least a portion of the thermoset material to the at least a portion of the cellular thermoplastic foam to provide a unitary composite cushioning structure.

Abstract: A reboundable optical structure includes a base layer; and an optical element layer formed with a reboundable polymeric material and attached to the base layer. The optical structure can include a diffuser, fresnel lens, linear prism film, collimating film, lenticular elements, and retroreflective structures. A method for forming a reboundable optical structure includes providing a base layer; and attaching an optical element layer formed with a reboundable polymeric material and attached to the base layer, thereby forming an optical structure.

Abstract: A floormat arranged to shed fluids has a topside and an underside. The floormat is placed where a user is expected to stand during a procedure. Fluids released during the procedure are allowed to fall onto and be shed off the floormat before being removed. The floormat may be discarded before starting another procedure. The mat is formed, at least in part, of compressible and resilient material. The topside of the mat has a spaced plurality of channels. In one instance, each of the channels has a floor sloping in opposite directions from a central peak. In another instance, the mat has a tapered apron bordering a central section that is convexly crowned to shed fluids. In other embodiments the topside of the central region is substantially flat except for the spaced plurality of channels. The floormat may be placed where an operator is expected to stand during the procedure. Fluids that fall onto the floor mat are shed therefrom and then removed. The floormat is discarded before starting another procedure.

Abstract: A building board as a carrier for a surface cladding of tiles, a plaster or a thin-layer trowel mortar has a moisture-resistant foam core layer which is provided on both sides with a paper or plastic film web on which a fibre material web made of nonwoven fabric or a knitted or machine-knitted fabric defining the outer side of the building board is disposed. The building board is provided with at least one groove which extends from a face side of the building board to the opposing face side of the building board, and largely penetrates the foam core layer from an outer side of the building board.

Abstract: The present invention provides a sealing material having excellent water resistance for a long time. A sealing material A of the present invention comprises: a rubber resin sheet 1; and a thermoplastic resin foam layer 2 formed at least on one surface of the rubber resin sheet 1. The sealing material A has a 25% compressive strength in a thickness direction of 2 to 40 kPa as measured in accordance with JIS K6767 and the thermoplastic resin foam layer 2 has a closed cell ratio of 10 to 60%. As a result, the sealing material A has excellent water resistance right after the use thereof and even after a lapse of a long time, and is suitably used in various applications.

Abstract: A superstrong adhesive tape that in a strongly viscous structure simultaneously having an adhesive function and an adsorptive function, realizes an enhanced bonding strength. There is provided a super-strong adhesive tape comprising plastic foam material (2) having holes (20) opening on its adhesion-object side; and adhesive agent layer (3) fitted on the adhesion-object side of the plastic foam material (2) so as to form depressed portions (30) at positions corresponding to the holes (20). The depressed portions (30) are deformed into a nearly planar configuration in conformity with any compressive deformation of the plastic foam material (2), and exert an adsorptive function in accordance with the elastic recovery of the plastic foam material (2).

Abstract: A biodegradable and renewable film that may be employed in a wide variety of applications is provided. The film is formed from a thermoplastic composition that contains at least one starch and at least one plant protein. Even at a high renewable material content, the present inventors have discovered that films may be readily formed from plant proteins and starches by selectively controlling the individual amount of the starch and plant proteins, the nature of the starch and plant proteins, and other components used in the film. Balancing the amount of starches and plant proteins within a certain range, for instance, can reduce the likelihood of plant protein aggregation and enhance the ability of the composition to be melt processed. The composition also contains at least one plasticizer that improves the thermoplastic nature of the protein and starch components. The selection of the plasticizer may also help reduce the tendency of the plant protein to aggregate during melt processing.

Abstract: A laminate comprising a tough, flexible, hard layer and a cushion layer for uses such as in making a compact, athletic equine boot that resists turning on the animal's hoof when the animal such as a horse is jumping, running and turning in water, mud, sand and sawdust comprising a bell portion having a cushiony layer on the interior of a relatively rigid or hard shell, an internal compressible protrusion, a fastener to secure the boot on the hoof, the hard shell being flexible and strong to resist blows from over-reaching rear hooves. The invention also includes a method of making the laminate comprising a layer of a tough, flexible, strong material and a cushiony layer.

Abstract: A foam product includes a foam core, at least one elastic buffer and a foam skin. The foam core defines an area on a surface thereof. The elastic buffer has a bottom surface bonded to the area of the surface of the foam core. The foam skin has a bottom surface bonded to a top surface of the elastic buffer and other areas of the surface of the foam core. The elastic buffer is made of foam materials and is elastic than the foam core. Additionally, the elastic buffer causes a bulge in the first foam skin.

Abstract: The present invention relates to a method for forming a bi-layered carpet underlay. More particularly, the method includes bonding a layer of non-woven fibers and a layer of re-bonded foam particles together to form the bi-layered carpet underlay. The layers of the carpet underlay can be bonded together with the use of adhesives, by heating a surface of one or both layers to a soft bondable state for lamination between the layers, by applying a film having adhesive surfaces between the layers, or by other suitable bonding means. The bi-layered carpet underlay combines the soft cushioning resilience of foam with the high durability bridging ability of fiber to provide a carpet underlay that maintains its height or thickness and firmness, while imparting softness and cushioning effects over an extended period of wear.

Abstract: To provide a crystalline polymer microporous membrane including: a microstructure on the side of one surface of the membrane, the microstructure being composed of series of nodules interconnected with one another by fibrils, wherein the average pore diameter at the one surface of the membrane is larger than the average pore diameter at another surface of the membrane, and the average pore diameter continuously changes from the one surface toward the other surface, and wherein the nodules have an aspect ratio (length/width) of 25 or greater.

Abstract: Disclosed is a resin molded article characterized by comprising a resin base as a hard foamed body composed of a thermosetting resin, a resin film composed of a thermoplastic resin, and a skin layer formed therebetween, wherein the skin layer is composed of the same thermosetting resin as that of the resin base and has a density larger than that of the resin base. Consequently, the strength of the surface of a resin base acting as an interface with a superficial layer of the resin molded article or the strength of a portion including the surface is increased, thereby suppressing deformation of the surface of the molded article and improving moldability as a resin molded article.

Abstract: The present invention relates to a corrugated product comprising a corrugated substrate, having a top surface and a bottom surface, laminated with a sheet material on its top and/or bottom surface. The substrate is selected from the group consisting of low-density polyethylene foam, high-density polyethylene film, low-density polyethylene film, polypropylene, Nylon 6,6, Nylon 6, paper, craft paper or Cotton Paper. The sheet material is selected from the group consisting of paper, polyethylene film, foil, low density polyethylene foam, high density polyethylene film, low density polyethylene film, polypropylene, Nylon 6,6, Nylon 6, paper, craft paper, Cotton Paper. The sheet material can have a pressure sensitive adhesive and backing paper applied to the side of the sheet not attached to the substrate.

Abstract: The invention pertains to a Pottery Slab Rolling Mat with surface which is fabricated and formed with characteristics to produce a smooth low surface tension with minuet air pockets which allow the release of ceramic or clay materials. The material used to formulate the Pottery Slab Rolling Mat is formulated of non-moister absorbing foam which together with the surface fabrication, allow simple and clean release of rolled ceramic or clay materials.

Abstract: A thermoplastic film for the interior paneling of motor vehicles has a top layer with a structured surface layer and a foamed layer on the underside and with indentations or material weak points introduced on the reverse side. The top layer has a residual thickness of at least 35% in the region of the indentations and the foamed layer has a thickness between 15 and 50% of the density of the compact top layer.

Abstract: This invention refers to synthetic decorative coverings in order to cover and protect trafficable surfaces.

Abstract: A method for the production of a fixing piece (12, 36) serves for fixing of covering material to cushion pieces for vehicle seats. A profile body (12) is connected to a separately produced sewn tag (36) which at least partly engages in a housing opening (34) in the profile body (12). The profile body (12) and the sewn tag (36), at least in the common jointing positions thereof, are predominantly made of plastic materials. According to the present invention, the known welding and glued connecting applications can be further improved such that the production method can be rapidly carried out with low production costs and without additional materials. A strong connection can be achieved, conforming to more stringent environmental aspects.

Abstract: A communications cable is provided comprising a conductor and polymer insulation encasing said conductor, the polymer insulation having a foamed interior and having an exterior surface formed from longitudinally running rounded peaks and valleys. A process is also provided for producing this polymer insulation or unfoamed polymer insulation having the same or similar peak/valley exterior surface by extruding molten thermoplastic polymer through an orifice to coat a conductor passing through the orifice, thereby forming polymer insulation on the conductor, said orifice defining the exterior surface of said polymer insulation comprising longitudinally running rounded peaks and valleys, said peaks covering at least about 30% of said exterior surface and having a height that is at least 50% of the width of said peaks.

Abstract: A porous resin substrate and a manufacturing method thereof. The substrate comprises a porous resin film having at least one functional part including electrodes or circuits, or both of them, and the porous resin film has a height-altered part, the height of which is different from the height of the functional part.

Abstract: An object of the invention is to provide a leather-like sheet having excellent water absorbability (sweat absorbability, defined the same hereinafter), providing a natural leather-like touch, and suitably used as a ball covering or a non-slip covering, without lowering surface wear resistance. An aspect of the invention is directed to a leather-like sheet including a base material having an entangled fiber sheet; and a porous elastic resin layer laminated on a surface of the base material. The porous elastic resin layer has a concave-convex surface. The concave-convex surface of the porous elastic resin layer includes a projection having a top surface and a side surface, and a recess having a bottom surface contiguous to the side surface. The top surface of the projection has openings with a diameter from 10 to 500 nm at a density of 1,000 openings/mm2 or more.

Abstract: A process for producing a porous laminate having many micropores interconnected in the thickness direction, which comprises: a step in which a laminate is produced which comprises at least three layers comprising an interlayer made of a thermoplastic resin having a hard segment and a soft segment and two nonporous outer layers made of a filler-containing resin and located as outer layers respectively on both sides of the interlayer; a step in which the laminate obtained is impregnated with a supercritical or subcritical fluid and this state is relieved to vaporize the fluid and thereby make the interlayer porous; and a step in which the two nonporous outer layers located respectively on both sides are made porous by stretching.