UV curable encapsulant

1. A liquid encapsulant composition comprising:

an acrylic or methacrylic block copolymer, of the general formula:

B-(A)n,

in which:

n is a natural integer greater than or equal to 1,

B represents an acrylic or methacrylic polymer block composed of a sequence of monomer units which can be polymerized by the radical route, the overall Tg of which is less than 0° C.,

A is an acrylic or methacrylic polymer block composed of a sequence of monomer units which can be polymerized by the radical route, the overall Tg of which is greater than 0° C.,

block B represents at least 50% w/w of the block copolymer,

at least one acrylic or methacrylic monomer and/or oligomer, and

at least one photoinitiator.

2. Composition according to claim 1 comprising in weight:

from 10 to 90% of said acrylic or methacrylic block copolymer;

from 10% to 60% of said acrylic or methacrylic monomer and/or oligomer

from 0.1 to 10% of photo-initiator,

based on the total weight of the composition.

3. Composition according to claim 1 in which the block B contains repeating units of alkyl acrylate or methacrylate selected in the group consisting of: butyl acrylate, hexyl acrylate, octyl acrylate, ethoxylated acrylates, C 16 —C 18 alkyl methacrylate, and polypropylene glycol monomethacrylate.

4. Composition according to claim 1 in which the block A contains repeating units of methyl methacrylate.

5. Composition according to claim 1 in which said acrylic or methacrylic monomer and/or oligomer is an alkyl acrylate or an alkyl methacrylate having a Tg of less than 0° C. chosen in the group consisting of: ethoxylated acrylates, polypropylene glycol monomethacrylate, triethylene glycol diacrylate (TEGDA), tripropylene glycol diacrylate (TPGDA), alkoxylated diacrylate, propoxylated 2-neopentyl glycol diacrylate, pentaerythritol tetraacrylate (PETTA), ethoxylated trimethylolpropane triacrylate and cyclic trimethylolpropane formal acrylate (CTFA).

6. Composition according to claim 1 in which said acrylic or methacrylic monomer and/or oligomer is an alkyl acrylate or an alkyl methacrylate having a Tg of less than 0° C. and is chosen in the group consisting of: hydroxy ethyl methacrylate, hydroxy propyl methacrylate, tetrahydrofurfuryl acrylate or methacrylate and methyl methacrylate.

7. Composition according to claim 1 further comprising from 0 to 50% of plasticizer.

8. Composition according to claim 1 further comprising from 0 to 20% in weight of an adhesion promoter selected in the group consisting of: vinyl silane, methacryloxy or acryloxy silane, organo-titanate and organo zirconate.

9. Material obtained by UV-curing, UV-Visible curing or visible light curing of the liquid encapsulant composition according to claim 1 .

10. A method for improving adhesion of encapsulant compositions to substrates comprising providing acrylic or methacrylic block copolymers according to claim 1 within the encapsulant compositions.

11. Process for encapsulating PV cells, comprising a step of UV-curing, UV-Visible curing or visible light curing the liquid encapsulant composition according to claim 1 .

12. A method for encapsulating PMMA- or Polycarbonate or cyclic olefin-based PV devices, comprising applying the encapsulant composition according to claim 5 to said devices.

13. A method for encapsulating silicon PV cells between transparent glass or polymeric front sheet and glass or metal or polymeric backsheet, comprising applying the encapsulant composition according to claim 6 to said cells.