Aqueous silicone dispersion

• US 6,521,699 B2
• Filed: 04/27/2001
• Issued: 02/18/2003
• Est. Priority Date: 09/26/1996
• Status: Expired due to Term

• Current Assignee: Bluestar Silicones France SAS
• Original Assignee: Rhodia Chimie (Solvac SA)
• Inventors: Jost, Philippe, Duchamp, Marie-Cécile, Letoffe, Michel, Feder, Michel
• Primary Examiner(s): Moore, Margaret G.
• Application Number:
  US09/844,981
• Publication Number:
  US 20010031818A1
• Time in Patent Office: 662 Days
• Field of Search: 524/837, 524/588, 524/838
• US Class Current: 524/588
• CPC Class Codes: C08G 77/16 to hydroxyl groups
• CPC Class Codes: C08G 77/20 containing silicon bound to unsaturated aliphatic groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/80 Siloxanes having aromatic substituents, e.g. phenyl side groups
• CPC Class Codes: C08J 2383/04 Polysiloxanes
• CPC Class Codes: C08J 3/03 in aqueous media
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 Polysiloxanes

Abstract

The invention concerns a silicon dispersion hardenable by cross-linking and useable particularly as putty, paint or film coating. The dispersion according to the instant invention contains hydroxylated condensable constituents and is free from hydrolyzable substituents capable of being transformed into volatile organic compounds, is free from volatile organic compounds and polyvinil alcohol, and contains an α,ω-diOH polyorganosiloxane (A), an adherence promoter (B) with NH₂ functions and OH functions, and, optionally, a catalyst (C), a surfactant (D), a cross-linking agent (E), fillers (F), a dispersing agent (G), a plasticizer (H), an antifungal agent (I), an antifoaming agent (J), a stabilizer (K) or a base (L). The invention is useful for putty or film coatings prepared with this dispersion.

Claims

1. An aqueous silicone dispersion having a volatile organic compounds content of less than or equal to 0.5% by weight, which can be cross-linked, by condensation, to an adherent elastomer, comprising, condensable hydroxylated constituents free of hydrolysable organo functional substituents, capable of generating volatile organic compounds in situ during the hydrolysis or during the cross-linking by condensation;

said dispersion comprising;

A—

at least one polydiorganosiloxane having, per molecule, at least two OH groups;

B—

at least one water-soluble adherence promoter being a silane or a polyorganosiloxane which is hydroxylated and carry, per molecule, at least one hydroxyl group and at least one hydrophilic function for anchoring onto a support, hereafter referred to as Fas, being identical to or different from each other and selected from the group consisting of amino, acrylo, methacrylo, ureido, mercapto, thiol, and chloroalkyl,

the silane being monoFas-trihydroxy-monosilane,

the polyorganosiloxane being obtained by one of the two following processes;

process 1;

a) co-hydrolysis of at least one silane S₁ substituted with Fas groups and with at least a —

OR group wherein R is an hydrocarbon group which are identical to or different, and of at least one silane S₂ substituted with —

OR groups which are identical to or different, excluding Fas substituents, to obtain hydrolysates,

b) heterocondensation of the hydrolysates derived from the silanes S₁ and S₂,

c) and then stripping or steam distillation of the hydrolysates derived from the —

OR groups,

process 2;

aa) hydrolysis of a silane S₃ substituted with Fas groups and —

OR groups, to obtain hydrolysed S₃ silanes and hydrolysates derived from the —

OR groups,

bb) homocondensation of the hydrolysed S₃ silanes,

cc) and by “

stripping”

vapour distillation of the hydrolysates derived from the —

OR groups,

the products of hydrolysis of alkoxylated epoxyfunctional silanes being excluded,

C—

optionally, at least one organometallic condensation catalyst,

D—

optionally, at least one surfactant,

E—

and, optionally, at least one cross-linking agent with the proviso that;

in the presence of the cross-linking agent (E), the promoter (B) only contains at least one OH group per molecule, and

in the absence of the cross-linking agent (B), the promoter (B) or the POS (A) comprises at least three OH groups.

2. A dispersion according to claim 1, free of polyvinyl alcohol.

3. A dispersion according to claim 2, further comprising, in addition to the constituents (A) and (B), at least one catalyst (C).

4. A dispersion according to claim 1, free of polyvinyl alcohol and comprising, in addition to the constituents (A), (B) and (C), at least one surfactant (D) and at least one cross-linking agent (E).

5. A dispersion according to claim 1, wherein the polyorganosiloxane (A) is an oil of formula:

wherein n≧

10, R¹ and R² identical or different are hydroxyl, a cyclo(C₁-C₆ alkyl), a cyclo(C₁-C₆ alkenyl), methyl, ethyl, propyl, phenyl, vinyl, 3,3,3,-trifluoropropyl, or amine.

6. A dispersion according to claim 5, wherein R¹ and R² are methyl.

7. A dispersion according to claim 1, wherein the water-soluble adherence promoter (B) is a linear hydroxylated polydiorganosiloxane with siloxyl units D or MD, or a hydroxylated polydiorganosiloxane resin comprising siloxyl units T and optionally M, D, Q or alternatively siloxyl units Q and M, D, or T, the promoter is free of volatile organic compounds and is not substituted with hydrolysable organo functional groups, and said promoter carries at least one function for anchoring onto a support linked to at least one silicon atom.

8. A dispersion according to claim 7, wherein the promoter (B) is a resin selected from the group consisting of T(OH), DT(OH), DQ(OH), DT(OH), MQ(OH), MDT(OH), and MDQ(OH).

9. A dispersion according to claim 1, wherein no crosslinking agent is present or said dispersion further comprises a cross-linking agent (E) comprising:

at least one hydroxylated resin having, per molecule, at least two different siloxyl units selected from the group consisting of M, D, T and Q ;

at least one being a T or a Q;

or

at least one siliconate, one silicate, powdered silicas, or colloidal silicas.

10. A dispersion according to claim 9, wherein the resin is a resin MQ, MDQ, TD or MDT.

11. A dispersion according to claim 1, further comprising a siliceous or nonsiliceous filler (F).

12. A dispersion according to claim 11, wherein said filler is a precipitated silica, a non precipitated silica, a colloidal silica, a powdered silica, or a carbonate.

13. A dispersion according to claim 11, further comprising one or more dispersants (G).

14. A dispersion according to claim 13, further comprising one or more plasticizers (H).

15. A dispersion according to claim 14, further comprising one or more antifungals (I).

16. A dispersion according to claim 15, further comprising one or more antifoams (J).

17. A dispersion according to claim 16, further comprising one or more stabilizers or thickeners (K).

18. A dispersion according to claim 17, further comprising one or more bases (L).

19. A putty, sealing material, film, paint or coating comprising a dispersion according to claim 1.