Curable organosiloxane block copolymer emulsions
View Patent ↗The present disclosure provides aqueous silicone emulsions of a “resin-linear” organosiloxane block copolymers. The present disclosure further provides a process for making these emulsions by forming a mixture of an organosiloxane block copolymer, admixing a sufficient amount of water to the mixture from to form an emulsion, and optionally further shear mixing the emulsion. The present invention further relates to the cured and/or coating compositions prepared from the present emulsions.
1. An aqueous silicone emulsion comprising:
A) an organosiloxane block copolymer comprising;
40 to 90 mole percent disiloxy units of the formula [R 1 2 SiO 2/2 —]
10 to 60 mole percent trisiloxy units of the formula [R 2 SiO 3/2 ]
0.5 to 35 mole percent silanol groups [≡SiOH]
where R 1 is independently a C 1 to C 30 hydrocarbyl,
R 2 is independently a C 1 to C 20 hydrocarbyl,
wherein;
the disiloxy units [R 1 2 SiO 2/2 —] are arranged in linear blocks having an average of from 10 to 400 disiloxy units [R 1 2 SiO 2/2 —] per linear block,
the trisiloxy units [R 2 SiO 3/2 ] are arranged in non-linear blocks having a molecular weight of at least 500 g/mol, and at least 30% of the non-linear blocks are crosslinked with each other,
each linear block is linked to at least one non-linear block, and the organosiloxane block copolymer has a molecular weight of at least 20,000 g/mole;
B) 0.1 to 50 parts by weight of an emulsifier for every 100 parts by weight of the organosiloxane block copolymer.
2. The silicone emulsion of claim 1 wherein R 2 is phenyl or methyl.
3. The silicone emulsion of claim 1 wherein R 2 is phenyl.
4. The silicone emulsion of claim 1 wherein each R 1 is independently methyl or phenyl or a combination of both.
5. The silicone emulsion of claim 1 wherein a portion of the disiloxy units have the formula [(CH 3 )(C 6 H 5 )SiO 2/2 —].
6. The silicone emulsion of claim 1 wherein a portion of the disiloxy units have the formula [(CH 3 ) 2 SiO 2/2 —].
7. The silicone emulsion of claim 1 where the emulsifier is an ethoxylated fatty alcohol.
8. The silicone emulsion of claim 1 where the emulsifier is a dodecylbenzene sulfonate.
9. A process for making a silicone emulsion comprising:
I) forming a mixture comprising;
A) 100 parts by weight of an organosiloxane block copolymer comprising;
40 to 90 mole percent disiloxy units of the formula [R 1 2 SiO 2/2 —]
10 to 60 mole percent trisiloxy units of the formula [R 2 SiO 3/2 ]
0.5 to 35 mole percent silanol groups [≡SiOH]
where R 1 is independently a C 1 to C 30 hydrocarbyl,
R 2 is independently a C 1 to C 20 hydrocarbyl,
wherein;
the disiloxy units [R 1 2 SiO 2/2 —] are arranged in linear blocks having an average of from 10 to 400 disiloxy units [R 1 2 SiO 2/2 —] per linear block,
the trisiloxy units [R 2 SiO 3/2 ] are arranged in non-linear blocks having a molecular weight of at least 500 g/mol, and at least 30% of the non-linear blocks are crosslinked with each other,
each linear block is linked to at least one non-linear block, and the
organosiloxane block copolymer has a molecular weight of at least 20,000 g/mole;
c) optionally a solvent; and
B) 0.1 to 50 parts by weight of an emulsifier,
II) admixing a sufficient amount of water to the mixture from step I) to form an emulsion,
III) optionally, further shear mixing the emulsion.
10. A coating composition comprising the silicone emulsion of claim 1 .
11. A cured product of the silicone emulsion of claim 1 .
12. A coating composition comprising the cured product of claim 11 .
13. The coating composition of claim 12 wherein the coating is transparent.
14. The cured product of claim 11 wherein the cured product has a tensile strength of at least 0.1 MPa, and a % elongation of at least 50%.
15. A method of forming a coating comprising: applying a film of the silicone emulsion of claim 1 to a surface, and curing the film to form a coating.
16. The silicone emulsion of claim 1 , wherein a portion of the disiloxy units have the formula [(CH 3 )(C 6 H 5 )SiO 2/2 ] and another portion of the disiloxy units have the formula [(CH 3 ) 2 SiO 2/2 ].