Method of providing flow control of heat activated sealant using a combination sealant/flow control agent
View Patent ↗A method of controlling the flow of a heat activated expandable sealant is provided in which a heat activated sealant is coated with a flow control agent having a melt flow rate which is lower than that of the sealant. The combination sealant/flow control agent is preferably used to seal gaps or cavities in parts such as components in automotive vehicles with minimal sagging.
1. A combination consisting of a heat activated expandable sealant and a flow control agent directly contacting and covering at least a portion of the surface of said sealant, said combination overlying a gap or cavity in a substrate with said sealant directly contacting said substrate; wherein said heat activated expandable sealant has a melt flow rate which is higher than the melt flow rate of said flow control agent; and wherein said heat activated expandable sealant has been heated to a temperature sufficient to cause said sealant to flow into and seal said gap or cavity; and wherein said heat activated expandable sealant with said flow control agent exhibits less sagging over said gap or cavity than a heat activated expandable sealant without said flow control agent.
2. The combination of claim 1 wherein said flow control agent comprises polyvinyl acetate.
3. The combination of claim 1 wherein said heat activated expandable sealant is in the form of an extruded sheet or thermoformed part.
4. The combination of claim 1 Wherein said heat activated expandable sealant and said flow control agent have been heated to a temperature between about 250° F. to 400° F.
5. The combination of claim 1 wherein said flow control agent is in the form of a mesh or film.
6. The combination of claim 1 wherein said flow control agent is in the form of a dry coating which has been applied to said sealant as a liquid coating.
7. A combination consisting of a heat activated expandable sealant and a flow control agent directly contacting and covering at least a portion of the surface of said sealant, said combination overlying a gap or cavity in a substrate with said sealant directly contacting said substrate; wherein said heat activated expandable sealant includes a blowing agent and said sealant has been heated to a temperature sufficient to cause said sealant to flow into and seal said gap or cavity; and wherein said heat activated expandable sealant has a melt flow rate which is higher than the melt flow rate of said flow control agent.
8. The combination of claim 7 wherein said sealant is in the form of a thermoformed part.
9. The combination of claim 8 wherein said thermoformed part comprises a pocket sealer.
10. A combination consisting of a heat activated expandable sealant and a flow control agent directly contacting and covering at least a portion of the surface of said sealant, said flow control agent comprising polyvinyl acetate, said combination overlying and sealing a gap or cavity in a substrate with said sealant directly contacting said substrate; wherein said heat activated expandable sealant has a melt flow rate which is higher than the melt flow rate of said flow control agent.
11. A combination consisting of a heat activated expandable sealant in the form of a thermoformed part and a flow control agent directly contacting and covering at least a portion of the surface of said sealant said combination overlying and sealing a gap or cavity in a substrate with said sealant directly contacting said substrate; said heat activated expandable sealant having a melt flow rate which is higher than the melt flow rate of said flow control agent.
12. A combination consisting of a heat activated expandable sealant and a flow control agent directly contacting and covering at least a portion of the surface of said sealant, said combination overlying and sealing a gap or cavity in substrate with said sealant directly contacting said substrate; wherein said heat activated expandable sealant has a melt flow rate which is higher than the melt flow rate of said flow control agent.