Polyurethane foam, method for the production and use thereof
AssigneeSaint-Gobain Performance Plastics Chaineux
InventorsGeorges Moineau, Marc Mertens, Dominique Petit
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Abstract
The subject of the invention is a water-impermeable flexible polyurethane foam obtained by reacting a polyol component, which comprises at least one hydrophobic polyol, with a polyisocyanate component in the presence of a foaming agent, characterized in that it has a compresson force of less than or equal to 12 kPa for 50% compression. Advantageously it has a density not exceeding 150 kg/M3, preferably not exceeding 60 kg/M3. The foam may be obtained by a cast-foam manufacturing process or by molding. It can be used as a water-impermeable seal.
Claims21
1 A water-impermeable flexible polyurethane foam obtained by reacting a polyol component, which comprises at least one hydrophobic polyol, with at least one polyisocyanate component in the presence of a foaming agent, characterized in that it has a compression force of less than or equal to 12 kPa for 50% compression and in that the molar ratio of the isocyanate functional groups to the total of the alcohol functional groups and reactive functional groups (the index) is less than 0.90.
2 The polyurethane foam as claimed in claim 1, characterized by a compression force of around 8 to 12 kPA for 50% compression.
3 The polyurethane foam as claimed in claim 1, characterized in that it has a density not exceeding 150 kg/m3.
4 The polyurethane foam of claim 1, characterized in that at least one component from the polyol component and the polyisocyanate component has a functionality strictly greater than 2.
5 The polyurethane foam of claim 1, characterized in that the isocyanate index is less than or equal to 0.85.
6 The polyurethane foam of claim 1 characterized in that the polyol component reacts with the polyisocyanate component in the presence of a monofunctional alcohol or amine component.
7 The polyurethane foam of claim 1 characterized in that the hydrophobic polyol has a fatty hydrocarbon chain.
8 The polyurethane foam as claimed in claim 7, characterized in that the hydrophobic polyol is derived from a fatty acid dimer.
9 The polyurethane foam of claim 1 , characterized in that the polyisocyanate component comprises predominantly 4,4′-methylene-bis(phenylisocyanate)(4,4′MDI).
10 The polyurethane foam as claimed in claim 9, characterized in that the polyisocyanate component contains at least 30 mol% of the 2,4′MDI isomer.
11 The polyurethane foam of claim 1 , characterized in that the foaming agent comprises water.
12 The polyurethane foam of claim 1 , characterized in that it is obtained in the presence of at least one additive, having at least one reactive functional group that reacts with the polyisocyanate compound or with the polyol compound.
13 A process for manufacturing a polyurethane foam as claimed in claim 1, characterized in that it comprises the
- a reaction mixture comprising the polyol component, the polyisocyanate component and the foaming agent is prepared;
- the reaction mixture is cast on a conveyor belt;
- and
- the conveyor belt and the cast mixture are made to run through a crosslinking oven.
14 The process as claimed in claim 13, characterized in that an upper protective film is deposited on the cast mixture, and the conveyor belt and the cast mixture coated with the upper protective film are made to run through a crosslinking oven.
15 The process of claim 14 , characterized in that a lower protective film is placed beforehand on the conveyor belt.
16 The process of claim 15 , characterized in that the lower protective film or the upper protective film is provided with an adhesive on its face in contact with the reaction mixture.
17 The process of claim 15 , characterized in that the lower protective film and/or the upper protective film are removed and another film provided with an adhesive is attached to a free face of the foam strip.
18 A process for manufacturing a polyurethane foam as claimed in claim 1, characterized in that it comprises
- a reaction mixture comprising the polyol component, the polyisocyanate component and the foaming agent is prepared;
- the reaction mixture is injected or cast in a closed or open mold;
- and - the mixture is crosslinked in the mold.
19 (canceled)
20 The polyurethane foam as claimed in claim 2, wherein the polyurethane foam has a density not exceeding 150 kg/m3.
21 The polyurethane foam as claimed in claim 1, wherein the polyurethane foam has a density not exceeding 60 kg/m3.