Use of UV-radiation-hardenable polyurethane resins for producing solar laminates

1. A process for the production of solar laminates including the step of utilizing a radiation-curable resin composition comprising at least one isocyanate-functional compound which has at least one radiation-curing group selected from the group consisting of vinyl, propenyl, allyl, vinyl ether, maleyl, fumaryl, maleimide, dicyclopentadienyl, acrylamide, and (meth)acrylate groups (component A), and at least one polyol (component B).

2. The process as claimed in claim 1 , wherein the radiation-curable composition comprises at least one unsaturated urethane acrylate which bears no isocyanate groups (component C) and at least one (meth)acrylate component (component D).

3. The process as claimed in claim 2 , wherein a double-bond functionality of the unsaturated urethane acrylate which bears no isocyanate groups (component C) is from 1 to 6.

4. The process as claimed in claim 2 , wherein the unsaturated urethane acrylate which bears no isocyanate groups (component C) is an unsaturated aliphatic urethane acrylate.

5. The process as claimed in claim 2 , wherein the (meth)acrylate component (component D) is selected from the group consisting of isobornyl (meth)acrylate, tetrahydrofurfuryl acrylate, 2-ethyloctyl acrylate, 2-ethylhexyl acrylate, and ethoxyethoxyethyl acrylate.

6. The process as claimed in claim 1 , wherein the isocyanate-functional compound which has at least one radiation-curing group selected from the group consisting of vinyl, propenyl, allyl, vinyl ether, maleyl, fumaryl, maleimide, dicyclopentadienyl, acrylamide, and (meth)acrylate groups is an isocyanate-functional urethane acrylate.

7. The process as claimed in claim 6 , wherein the NCO functionality of the isocyanate-functional urethane acrylate is from 0.8 to 6.

8. The process as claimed in claim 1 , wherein the radiation-curable composition comprises at least one initiator (component E).

9. The process as claimed in claim 1 , wherein the isocyanate-functional compound has (meth)acrylate groups.

10. The process as claimed in claim 1 , wherein the radiation-curable resin composition is free from organic solvents with boiling point <150° C.

11. The process as claimed in claim 1 , wherein the OH functionality of the polyol is from 1 to 6.

12. A solar laminate comprising a resin composition according to claim 1 comprising at least one isocyanate-functional compound which has at least one radiation-curing group selected from the group consisting of vinyl, propenyl, allyl, vinyl ether, maleyl, fumaryl, maleimide, dicyclopentadienyl, acrylamide, and (meth)acrylate groups (component A), and at least one polyol (component B).

13. A process for the production of a solar laminate comprising at least one solar cell having a frontal side, a reverse side, and reverse-side contacts attached thereto, a glass pane, and a reverse-side foil, where the process comprises the following steps:

a) application of a radiation-curable resin composition as claimed in claim 1 onto a reverse-side foil and a glass pane for attachment to a solar cell, wherein the radiation-curable resin composition comprises at least one isocyanate-functional compound which has at least one radiation-curing group selected from the group consisting of vinyl, propenyl, allyl, vinyl ether, maleyl, fumaryl, maleimide, dicyclopentadienyl, acrylamide, and (meth)acrylate groups (component A), and at least one polyol (component B,

b) hardening of the applied radiation curable resin composition by application of actinic radiation,

c) bringing the frontal side of a solar cell into contact with the resin layer produced on the glass pane,

d) bringing the reverse side of the solar cell into contact with the resin layer produced on the reverse-side foil,

e) passing the reverse-side contacts of the solar cell through the reverse-side foil,

f) introduction of the resultant layer composite formed by steps a) to e) into a vacuum laminator for the removal of included air, and

g) partial hardening of the remaining isocyanate and OH functionalities of the resin composition in the vacuum laminator under reduced atmospheric pressure, with effective adhesive bonding of the frontal and reverse sides of the solar cell and encapsulation of the solar cell.

14. A solar laminate produced by a process as claimed in claim 13 .

15. A process for the production of a solar laminate comprising at least one solar cell having a frontal side, a reverse side, and reverse-side contacts attached thereto, and a reverse-side foil, where the process comprises the following steps:

a) application of a radiation-curable resin composition as claimed in claim 1 onto a reverse-side foil for attachment to a solar cell, wherein the radiation-curable resin composition comprises at least one isocyanate-functional compound which has at least one radiation-curing group selected from the group consisting of vinyl, propenyl, allyl, vinyl ether, maleyl, fumaryl, maleimide, dicyclopentadienyl, acrylamide, and (meth)acrylate groups (component A), and at least one polyol (component B),

b) hardening of the applied radiation curable resin composition by application of actinic radiation,

c) bringing the reverse side of a solar cell into contact with the resin layer produced on the reverse-side foil,

d) passing the reverse-side contacts of the solar cell through the reverse-side foil,

e) application of a radiation-curable resin composition onto the frontal side of the solar laminate obtained after step d),

f) bringing the frontal side of the solar cell into contact with a glass pane,

g) introduction of the resultant layer composite into a vacuum laminator, and

h) partial hardening of the remaining isocyanate and OH functionalities of the resin composition in the vacuum laminator under reduced atmospheric pressure, and

i) after discharge from the laminator, hardening of the remaining double bonds of the resin composition by application of actinic radiation via the glass pane primed with groups having free-radical reactivity, and

j) adhesive bonding of the glass pane with the resin matrix and encapsulation of the solar cell.

16. A solar laminate provided by a process as claimed in claim 15 .

17. A process for the production of a solar laminate comprising at least one solar cell with a frontal side, a reverse side, reverse-side contacts attached thereto, and a reverse-side foil, where the process comprises the following steps:

a) application of an adhesive onto a reverse-side foil and/or the reverse side of a solar cell,

b) bringing the reverse side of the solar cell into contact with the reverse-side foil, and adhesive bonding of these,

c) passing reverse-side contacts of the solar cell through the reverse-side foil,

d) application of a radiation-curable resin composition as claimed in claim 1 onto the frontal side of the solar laminate obtained after step c) wherein the radiation-curable resin comprises at least one isocyanate-functional compound which has at least one radiation-curing group selected from the group consisting of vinyl, propenyl, allyl, vinyl ether, maleyl, fumaryl, maleimide, dicyclopentadienyl, acrylamide, and (meth)acrylate groups (component A), and at least one polyol (component B),

e) hardening of the resin composition by application of actinic radiation,

f) optionally protecting the flat-encapsulated cell obtained after step e) by application of a further frontal-side foil or a glass pane to the flat-encapsulated cell, using a vacuum-lamination process, and

g) optionally protecting the flat-encapsulated cell obtained after step e) by application of one or more further coatings.

18. A solar laminate provided by a process as claimed in claim 17 .