High refractive index compositions containing resin-linear organosiloxane block copolymers
View Patent ↗Solid compositions of organosiloxane block copolymers are disclosed having a refractive index greater than 1.5. The organosiloxane block copolymers comprise: 40 to 90 mole percent disiloxy units of the formula [R 1 2 SiC 2/2 ] 9 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 SiC 2/2 ] are arranged in linear blocks having an average of from 10 to 400 disiloxy units [R 1 2 SiC 2/2 ] per linear block, the trisiloxy units [R 1 2 SiC 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 (M w ) of at least 20,000 g/mole.
1. A solid composition comprising an organosiloxane block copolymer having
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 25 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, at least 30% of the non-linear blocks are crosslinked with each other,
and are predominately aggregated together in nano-domains,
each linear block is linked to at least one non-linear block,
the organosiloxane block copolymer has a molecular weight of at least 20,000 g/mole,
and the solid composition has a refractive index greater than 1.5.
2. The solid composition of claim 1 wherein the disiloxy units have the formula [(CH 3 )(C 6 H 5 )SiO 2/2 ].
3. The solid composition of claim 1 wherein the organosiloxane block copolymer contains at least 30 weight percent disiloxy units.
4. The solid composition of claim 1 wherein R 2 is phenyl.
5. The solid composition of claim 1 wherein the solid composition has a tensile strength greater than 1.0 MPa and an % elongation at break greater than 20%.
6. The solid composition of claim 1 wherein the coating composition has a melt flow temperature ranging from 25° C. to 200° C.
7. The solid composition of claim 1 wherein the composition has a storage modulus (G′) at 25° C. ranging from 0.01 MPa to 500 MPa and a loss modulus (G″) at 25° C. ranging from 0.001 MPa to 250 MPa.
8. The solid composition of claim 7 wherein the composition has a storage modulus (G′) at 120° C. ranging from 10 Pa to 500,000 Pa and a loss modulus (G″) at 120° C. ranging from 10 Pa to 500,000 Pa.
9. The solid composition of claim 7 wherein the composition has a storage modulus (G′) at 200° C. ranging from 10 Pa to 100,000 Pa and a loss modulus (G″) at 200° C. ranging from 5 Pa to 80,000 Pa.
10. The solid composition of claim 1 wherein the solid composition has an optical clarity of greater than 95% light transmittance.
11. The solid composition of claim 1 wherein the solid composition has a refractive index from about 1.5 to about 1.6.
12. The solid composition of claim 1 wherein the solid composition has a refractive index from about 1.50 to about 1.56.