the silicone resin substrate is a substrate that is either composed of a silicone resin or contains a silicone resin . there are no restrictions on the shape of this substrate , which may be a sheet , a tube , or a rod , and may also be a substrate in which a porous fluororesin is used as a structural support material , and is impregnated with a silicone resin . obviously , the present invention can also be similarly applied to a fluorosilicone resin that contains fluorine , for example . a preferred resin is polydimethyl siloxane the porous material used in the present invention needs to be porous , but there are no particular restrictions on the pore diameter . materials having a favorable porous structure are porous fluororesins , porous polyethylenes , and porous polypropylenes . of these , porous materials that can be used to particularly good advantage are those composed of expanded polytetrafluoroethylene . this type of material is discussed in detail in u . s . pat . no . 4 , 187 , 390 . moreover , since polytetrafluoroethylene materials have heat resistance of 260 ° c . or higher , are impervious to most chemicals , and have excellent electrical characteristics , these excellent characteristics of silicone resin substrates will not be sacrificed . polytetrafluoroethylene materials also have extremely good adhesion when used with an adhesive agent . the bonding of the silicone resin substrate and the porous material is performed using a known silicone - based adhesive agent . the use of a silicone - based adhesive agent is possible because this bonding involves impregnation with the adhesive agent from the porous material side . in bonding with this silicone - based adhesive agent , only a portion of the porous material ( in the thickness direction thereof ) is impregnated with the adhesive agent , and open pores are left in the remaining portion of the thickness . a composite material obtained in this manner is itself useful , but it is also possible to bond a second member as desired by utilizing the remainder of the porous material . the second member may be a resin , glass , ceramic , metal , wood , etc ., or a composite material of these . the adhesive agent that is used to bond the second member to the porous material should be appropriately selected according to the second member . the compounding of the silicone resin and the other material is accomplished by first bonding the silicone resin and the porous material together with the silicone - based adhesive agent . the silicone - based adhesive agent is not permitted to impregnate the entire thickness of the porous material , and most importantly , the silicone - based adhesive agent is not permitted to adhere over the surface of the other side of the porous material therefore , that side can be used with any adhesive agent , and the porous material side can also be coated with the second member . the reason for not allowing any silicone - based adhesive agent does adhere , the release properties will be extremely strong in that area , resulting in peeling in actual practice . the resin that is used to coat the other side of the porous material can be a fluororesin , an epoxy resin , a urethane resin , an acrylic resin , or the like , as dictated by the intended application , but the use of a fluororesin is preferable from the standpoint of taking advantage of the characteristics of the silicone resin that serves as the substrate . applications of the composite material of the present invention include gas selective permeable membranes , laminates of materials with high and low coefficients of friction , materials with heat sealing properties ( silicone resins have no heat sealing properties ), printable silicone resins ( silicone resins are extremely difficult to print ), and the like , although this list is not comprehensive . practical examples will now be given while referring to the figures . referring to fig1 a suitable amount of poly - dimethyl siloxane adhesive sealant 2 ( se9156 clear , made by toray - dow corning silicone ) was applied in drops to a silicone sheet 1 with a thickness of 2 mm and a high gas permeability ( ficon stock number 140c , made by fuji systems ), over which was applied a porous polytetrafluoroethylene material 3 with a thickness of 40 μm and a pore diameter of about 0 . 2 μm average ( made by japan gore - tex , inc .). here , the silicone adhesive sealant did not impregnate all the way through the thickness of the porous polytetrafluoroethylene . this composite was allowed to stand for approximately 24 hours at ambient temperature to cure the silicone adhesive sealant . referring to fig2 the porous polytetrafluoroethylene side of the substrate created in practical example 1 was coated with a solution obtained by dissolving an amorphous fluororesin 4 ( teflon af2400 , may by dupont , a hydrogen selective permeable resin ) in a solvent ( fluorinate , made by 3m ) in a concentration of 2 wt % such that the coating thickness would be 10 μm . this substrate was cured for approximately three hours at 100 ° c . to produce a hydrogen selective permeable membrane . since silicone resins also have excellent electrical characteristics , a copper foil was laid over a silicone resin to produce a printed circuit board . a 35 μm electrolytic copper foil was bonded over the porous polytetrafluoroethylene side of the substrate created in practical example 1 using an epoxy resin as the adhesive agent . in this case , the substrate was one - sided , but , naturally , a two - sided substrate could also be used . referring to fig3 a porous polytetrafluoroethylene material 13 with a thickness of 40 μm and a pore diameter of 0 . 2 μm ( made by japan gore - tex , inc .) which had been plated on one side with copper 12 was applied to a silicone resin 11 with a thickness of 1 mm using the above - mentioned silicone - based adhesive agent 14 , thereby producing a one - sided substrate . referring to fig4 the laminated material 21 from practical example 1 was cut into squares of approximately 20 cm , and these were placed between the floor and all four legs of the heavy shelf 24 ( weight : approximately 100 kg ). the squares were inserted such that the silicone resin 22 side faced the legs of the shelf , and the porous polytetrafluoroethylene material 23 side faced the floor . when the composite material was inserted , the heavy shelf could be removed with an extremely slight force of approximately 30 kg ( i . e . by one person ), but when the composite material was not inserted , the shelf could not be moved satisfactorily even with a force of approximately 150 kg . moreover , the floor was deeply scratched the instant the shelf was moved . the silicone resin side of this composite material clung fast to the legs of the shelf , while the porous polytetrafluoroethylene material slid along the floor because of its extremely low coefficient of friction , and consequently , this composite material did not come off during movement of the shelf , and the floor was not scratched . electrolytic capacitors are used in huge numbers nowadays as electronic components in televisions , radios , etc . one of the technological problems with electrolytic capacitors is the release of internally generated hydrogen gas . hydrogen gas is generated when these devices are used under supervoltage and high temperatures , used continuously for extended periods of time , used with improper positive - negative connection , etc ., and it is extremely hazardous for the internal hydrogen pressure to rise too high , and there can be an explosion even if a safety valve is installed . ethylene glycol is often used as the electrolyte inside electrolytic capacitors . accordingly , there is a need for a membrane that will allow hydrogen to pass through but not ethylene glycol vapor . at the same time , this membrane must have heat resistance of 200 ° c . or higher since it is exposed to heat during soldering and other such work . thereupon , the substrate 32 for practical example 2 was cut into a circle 7 mm in diameter and put at the bottom of an electrolytic capacitor 31 , as shown in fig5 . in the figure , 33 is a groove used for sealing . no swelling due to hydrogen gas occurred when this electrolytic capacitor was used at 100 ° c . for 100 hours under an applied voltage of 10 v , and , naturally , there was no explosion or other such occurrence . neither was there any drying up of the electrolyte ( ethylene glycol ), which means that the ethylene glycol vapor did not pass through the membrane . meanwhile , when an electrolytic capacitor having a conventional structure ( one in which solid polytetrafluoroethylene was used in place of the substrate from practical example 2 ) was used under the above conditions , swelling occurred as a result of hydrogen gas .