Breathable self-adhesive articles
The invention relates to the use of an adhesive composition comprising at least one silyl-containing polymer, at least one compatible tackifying resin and at least one catalyst, to make a breathable self-adhesive article. The invention also relates to a breathable self-adhesive article comprising at least one breathable substrate coated with a breathable adhesive layer. The invention also relates to a pressure-sensitive adhesive composition.
1. A self-adhesive article comprising:
a substrate having a Moisture-Vapour Transmission Rate superior or equal to 1000 g/m 2 /24 h, wherein at least one face of said substrate is coated with an adhesive layer obtained by curing an adhesive composition comprising at least one silyl-containing polymer, at least one compatible tackifying resin and at least one catalyst,
said adhesive layer having a Moisture-Vapour Transmission Rate superior or equal to 300 g/m 2 /24 h for a coating weight below 50 g/m 2 and a Moisture-Vapour Transmission Rate superior or equal to 100 g/m 2 /24 h for a coating weight superior or equal to 50 g/m 2 .
2. The self-adhesive article according to claim 1 , wherein the adhesive layer having a coating weight below 50 g/m 2 has a Moisture-Vapour Transmission Rate superior or equal to 500 g/m 2 /24 h.
3. The self-adhesive article according to claim 1 , wherein the adhesive layer having a coating weight superior or equal to 50 g/m 2 has a Moisture-Vapour Transmission Rate superior or equal to 200 g/m 2 /24 h.
4. The self-adhesive article according to claim 1 , wherein the adhesive layer has a coating weight below 50 g/m 2 and has a Moisture-Vapour Transmission Rate superior to 500 g/m 2 /24 h.
5. The self-adhesive article according to claim 1 , wherein the adhesive layer has a coating weight superior or equal to 50 g/m 2 and has a Moisture-Vapour Transmission Rate superior or equal to 400 g/m 2 /24 h.
6. The self-adhesive article according to claim 1 , wherein said at least one silyl-containing polymer is obtained by the following process:
a1) reacting a mixture of alcohols comprising a polyether polyol with a stoichiometric excess of diisocyanate, to form a polyurethane-polyether block having at least two terminal —NCO groups; and
b1) reacting the product obtained from a1) with a stoichiometric quantity or slight stoichiometric excess quantity of an alpha, beta or gamma-aminosilane.
7. The self-adhesive article according to claim 1 , wherein said at least one silyl-containing polymer is a silyl-containing polyurethane having polyurethane-polyether and polyurethane-polyester blocks, and said silyl-containing polyurethane is obtained by the following process:
a2) reacting a mixture of alcohols comprising a polyether polyol with a stoichiometric excess of diisocyanate, in order to form a polyurethane-polyether block having at least two terminal —NCO groups;
b2) reacting the product obtained from a2) with a stoichiometric excess of a polyester polyol, in order to form a polyurethane having polyurethane-polyether and polyurethane-polyester blocks comprising at least two terminal blocks consisting each in a polyurethane-polyester block having a terminal —OH group; and
c2) reacting said polyurethane obtained from b2) with a stoichiometric quantity of an isocyanatosilane.
8. The self-adhesive article according to claim 1 , wherein said tackifying resin is chosen from rosin ester resins and acrylic resins.
9. The self-adhesive article according to claim 1 , wherein the adhesive composition comprises:
a) from 20 to 85% by weight of at least one silyl-containing polymer;
b) from 15 to 80% by weight of at least one tackifying resin; and
c) from 0.01 to 3% by weight of at least one catalyst.
10. The self-adhesive article according to claim 1 , wherein the tackifying resin has a softening point inferior or equal to 150° C.
11. The self-adhesive article according to claim 1 , wherein the silyl-containing polymer is selected from the group consisting of a silyl-containing polyether, a silyl-containing polyurethane, a silyl-containing polyurethane having polyurethane-polyether and polyurethane-polyester blocks, and mixtures thereof.
12. The self-adhesive article according to claim 1 , wherein the tackifying resin is selected from the group consisting of phenol modified terpene resins, hydrocarbon resins, rosin ester resins, acrylic resins and mixtures thereof.
13. A method for making the self-adhesive article of claim 1 , comprising adhering the adhesive layer on the substrate.
14. The method according to claim 13 , wherein the adhesive layer having a coating weight below 50 g/m 2 has a Moisture-Vapour Transmission Rate superior or equal to 500 g/m 2 /24 h.
15. The method according to claim 13 , wherein the adhesive layer having a coating weight superior or equal to 50 g/m 2 has a Moisture-Vapour Transmission Rate superior or equal to 200 g/m 2 /24 h.
16. The method according to claim 13 , wherein the substrate has a Moisture-Vapour Transmission Rate superior or equal to the Moisture-Vapour Transmission Rate of the adhesive layer.
17. A process for manufacturing the self-adhesive article according to claim 1 , said process comprising:
a) conditioning the adhesive composition at a temperature from 20° C. to 160° C.;
b) coating the adhesive composition obtained from step a) onto a carrying surface;
c) curing the coated adhesive composition by heating the carrying surface at a temperature from 20° C. to 200° C.; and
d) laminating the cured adhesive layer onto the substrate having a Moisture-Vapour Transmission Rate superior or equal to 1000 g/m 2 /24 h.
18. The process according to claim 17 , wherein said curing is carried out in an atmosphere in which from 5 to 100% of the molecules are water molecules.