Cross-linkable silicone composition for the production of non-stick coatings for flexible supports and attachment promoting additive contained in this composition

1- Silicone composition capable of cross-linking/curing by polyaddition, for forming a coating which is water-repellent and non-stick on a support, and comprising:

• (A) an alkenylated silicone component containing at least one functional silicone oil comprising at least one PolyOrganoSiloxane (POS) comprising units of formula (I.1)
• W
• a
• 
• Z
• b
• 
• SiO
• 4
• -
• (
• a
• +
• b
• )
• 2
• (
• I
• 
• .1
• )
• in which:
• W represents independently a functional alkenyl group,
• Z represents independently a monovalent hydrocarbon group, with no unfavourable effect on the activity of the catalyst and chosen from the alkyl groups having 1 to 8 carbon atoms selected from the group consisting of the methyl, ethyl, propyl and 3,3,3-trifluoropropyl groups,
• a is 1 or 2, b is 0, 1 or 2 and a+b is comprised between 1 and 3;
• (B) at least one cross-linking silicone oil comprising at least one hydrogenated POS having, per molecule, at least three hydrogen atoms bound to the silicon;
• (C) at least one catalyst comprising at least one metal belonging to the platinum group;
• (D) at least one attachment promoting additive containing at least one epoxidated silicone oil comprising at least one PolyOrganoSiloxane (POS) comprising:
• units of formula (I.2):
• Y
• c
• 
• Z
• d
• 1
• 
• SiO
• 4
• -
• (
• c
• +
• d
• )
• 2
• (
• I
• 
• .2
• )
• optionally units of formula (I.3):
• Z
• e
• 2
• 
• SiO
• 4
• -
• e
• 2
• (
• I
• 
• .3
• )
• optionally units of formula (I.4):
• Y
• g
• ′
• 
• Z
• h
• 3
• 
• SiO
• 4
• -
• (
• g
• +
• h
• )
• 2
• (
• I
• 
• .4
• )
• optionally units of formula (I.5):
• H
• i
• 
• Z
• j
• 4
• 
• SiO
• 4
• -
• (
• i
• +
• j
• )
• 2
• (
• I
• 
• .5
• )
• formulae in which:
• Y represents independently a linear, branched or cyclic epoxy-functional hydrocarbon group;
• Y′ represents independently an alkoxy-functional group;
• Z1, Z2, Z3, Z4 are groups which correspond to the same definition as that given above for the Z groups in the legend to formula (I.1);
• c is 1 or 2, d is 0, 1 or 2 and c+d is comprised between 1 and 3;
• e is comprised between 0 and 3;
• g is 1 or 2, h is 0, 1 or 2 and g+h is comprised between 1 and 3;
• i is 1 or 2, j is 0, 1 or 2 and i+j is comprised between 1 and 3;
• this attachment promoting additive (D) comprising, per molecule, less than one Si—H unit;
• (E) optionally at least one cross-linking inhibitor;
• (F) optionally, an adhesion modulating system;
• (G) optionally, at least one diluent;
• (H) optionally, at least one other functional additive, in particular a “processing aid” operating auxiliary of the “anti-misting” additive type,
• wherein the attachment promoting additive (D) is chosen from the group of silicones comprising:
• 1. the POSs containing:
• (I.2) units with c=1 and c+d=2:
• Depoxy
• optionally (I.2) units with c=1 and c+d=3:
• Mepoxy
• optionally (I.3) units with e=2:
• D
• optionally (I.4) units with e=1 and g+h=1:
• Talkoxy
• optionally (I.4) units with e=1 and g+h=2:
• Dalkoxy
• optionally (I.4) units with e=1 and g+h=3:
• Malkoxy
• optionally (I.5) units with i=1 and i+j=2:
• D′
• optionally (I.5) units with i=1 and i+j=3:
• M′
• of formula
• M[D]do[Dalkoxy]da[Depoxy]de[D′]d′[Mepoxy]me[M′]m′M
• with
• 0≦do≦500, preferably 0≦do≦300;
• 0≦da≦50 preferably 0≦da≦40,
• 1≦dc≦40 preferably 2≦dc≦30;
• 0≦d′<1, preferably 0≦d′≦0.5;
• 0≦m′<1, preferably 0≦m′≦0.5;
• d′+m′ being less than 1, preferably less than or equal to 0.5;
• 0≦me≦2;
• 2. the POSs of average formula:
• M[D]do[Depoxy]de[Mepoxy]meM with do, de, me as defined above, and, still more preferably, the POSs of average formula below:
• in which:
• the symbols Z5 correspond to groups which are identical to or different from each other and correspond to the same definition as that given above for the Z groups in the legend to formula (I.1);
• 15≦p≦200, preferably 50≦p≦100, and,
• still more preferably 75≦p≦85;
• 0≦q≦20, preferably 1≦q≦15, and, still
• more preferably 6≦q≦9;
• r+s=3;
• 0≦r≦3;
• 0≦s≦3;
• t+u=3;
• 0≦t≦3;
• 0≦u≦3.
• 3. and mixtures thereof.