When silicone is used to fill joints in surfaces on which vehicles drive, it is advantageous if the silicone contains zinc oxide in the form of tetrapod-shaped crystals.

Provided is a rubber composition for sealing material which contains 100 parts by mass of a rubber component, 50 to 140 parts by mass of silica, 1 to 20 parts by mass of a silane coupling agent, and 15 to 35 parts by mass of carbon black. The rubber component is preferably an ethylene-propylene-diene rubber.

A combined sealing member is provided that includes a composition comprising two or more polyolefin elastomers selected from the group consisting of a dense, a micro-dense and a dynamic silane-crosslinked polyolefin elastomer having a respective density of less than 0.90 g/cm.sup.3, less than 0.70 g/cm.sup.3, and less than 0.60 g/cm.sup.3. The combined sealing member exhibits a compression set of from about 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @ 70° C.).

This dealcoholization room-temperature curable organopolysiloxane composition contains (A) a diorganopolysiloxane having a silicon atom-bonded hydroxy group and/or a hydrolyzable silyl group at both ends of the molecular chain, and has a coefficient of viscosity of 20-1,000,000 mPa.Math.s, (B) an organopolysiloxane which is a partial (co-)hydrolysis-condensation product of a hydrolyzable organosilane compound having one or more silicon atom-bonded alkenyl groups and 1-3 silicon atom-bonded alkoxy groups, per molecule, (C) a hydrolyzable organosilane compound having one or more phenylene backbones and two or more amino groups, per molecule, and/or a partial hydrolysis-condensation product thereof. The dealcoholization room-temperature curable organopolysiloxane composition has good curability and storage stability even when the composition does not contain a metal catalyst, is less toxic to the human body and is environmentally friendly, is cost-competitive, and has good rubber physical properties and adhesiveness after being cured.

A combined sealing member is provided that includes a composition comprising two or more polyolefin elastomers selected from the group consisting of a dense, a micro-dense and a dynamic silane-crosslinked polyolefin elastomer having a respective density of less than 0.90 g/cm.sup.3, less than 0.70 g/cm.sup.3, and less than 0.60 g/cm.sup.3. The combined sealing member exhibits a compression set of from about 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @ 70 C.).

A static sealing member is provided that includes a composition having a silane-crosslinked polyolefin elastomer with a density less than 0.90 g/cm.sup.3. The static sealing member can exhibit a compression set of from about 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @ 70 C.). The silane-crosslinked polyolefin elastomer can include a first polyolefin having a density less than 0.86 g/cm.sup.3, a second polyolefin having a crystallinity less than 40%, a silane crosslinker, a grafting initiator, and a condensation catalyst.

A microdense sealing member is provided. The microdense sealing member includes a composition having a foamed silane-crosslinked polyolefin elastomer with a density less than 0.70 g/cm.sup.3. The microdense sealing member can exhibit a compression set of from about 5.0% to about 35.0% measured according to ASTM D 395 (22 hrs @ 70 C.). The foamed silane-crosslinked polyolefin elastomer can be produced from a blend including a first polyolefin having a density less than 0.86 g/cm.sup.3, a second polyolefin having a crystallinity less than 60 C., a silane crosslinker, a grafting initiator, a condensation catalyst, and a microencapsulated foaming agent.

A combined sealing member is provided that includes a composition comprising two or more polyolefin elastomers selected from the group consisting of a dense, a micro-dense and a dynamic silane-crosslinked polyolefin elastomer having a respective density of less than 0.90 g/cm.sup.3, less than 0.70 g/cm.sup.3, and less than 0.60 g/cm.sup.3. The combined sealing member exhibits a compression set of from about 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @ 70 C.).

This dealcoholization room-temperature curable organopolysiloxane composition contains (A) a diorganopolysiloxane having a silicon atom-bonded hydroxy group and/or a hydrolyzable silyl group at both ends of the molecular chain, and has a coefficient of viscosity of 20-1,000,000 mPa.Math.s, (B) an organopolysiloxane which is a partial (co-)hydrolysis-condensation product of a hydrolyzable organosilane compound having one or more silicon atom-bonded alkenyl groups and 1-3 silicon atom-bonded alkoxy groups, per molecule, (C) a hydrolyzable organosilane compound having one or more phenylene backbones and two or more amino groups, per molecule, and/or a partial hydrolysis-condensation product thereof. The dealcoholization room-temperature curable organopolysiloxane composition has good curability and storage stability even when the composition does not contain a metal catalyst, is less toxic to the human body and is environmentally friendly, is cost-competitive, and has good rubber physical properties and adhesiveness after being cured.

A static sealing member is provided that includes a composition having a silane-crosslinked polyolefin elastomer with a density less than 0.90 g/cm.sup.3. The static sealing member can exhibit a compression set of from about 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @ 70? C.). The silane-crosslinked polyolefin elastomer can include a first polyolefin having a density less than 0.86 g/cm.sup.3, a second polyolefin having a crystallinity less than 40%, a silane crosslinker, a grafting initiator, and a condensation catalyst.