Silicone encapsulants for light emitting diodes

A polymeric composition produced by the process of reacting:

• a. a cyclosiloxane oligomer of the formula X:
• wherein n is an integer from 0 to 6;
• R in each occurrence is chosen independently from H, a methyl, an alkyl, and a haloalkyl, with the proviso that at least two of R must be H, with;
• b. a vinyl siloxane oligomer of formula XI
• wherein m is an integer from 2 to 20;
• R1 in each occurrence is chosen independently for each siloxane unit from CH3, OCH3, OCH2CH3, vinyl, and a further unit of [—O—SiR12—]q-OCH3, wherein q is an integer from 2 to 20;
• in the presence of a noble metal hydrosilation catalyst,
• with the provisos that at least one of R1 must be a vinyl containing unit, said vinyl siloxane oligomer having a viscosity from 10 centipoise to 10,000 centipoise, and a ratio of alkoxy groups to Si atoms in a range from 0.004:1 to 1.5:1;
• and
• c. a filler,
• in the presence of a noble metal hydrosilation catalyst, said polymeric composition having a refractive index from 1.3 to 2.5

A prepolymer mixture comprising:

• a) a cyclosiloxane oligomer of the formula X:
• wherein n is an integer from 0 to 6;
• R in each occurrence is chosen independently from H, a methyl, an alkyl, and a haloalkyl, with the proviso that at least two of R must be H, with;
• and
• b) a vinyl siloxane oligomer of the formula XI:
• wherein m is an integer from 2 to 20;
• R1 in each occurrence is chosen independently for each siloxane unit from CH3, OCH3, OCH2CH3, vinyl, and a further unit of [—O—SiR12—]q-OCH3, wherein q is an integer from 2 to 20;
• with the provisos that at least one of R1 must be a vinyl containing unit, said vinyl siloxane oligomer having a viscosity from 10 centipoise to 10,000 centipoise, and a ratio of alkoxy groups to Si atoms in a range from 0.004:1 to 1.5:1.

A light emitting device comprising:

• a substrate;
• a light emitting diode (LED), said LED operably integrated with said substrate;
• and
• a polymeric composition encapsulating said LED, said polymeric composition comprising a polymer produced by the process of reacting:
• a) a cyclosiloxane oligomer of the formula X:
• wherein n is an integer from 0 to 6;
• R in each occurrence is chosen independently from H, a methyl, an alkyl, and a haloalkyl, with the proviso that at least two of R must be H, with
• b) a vinyl siloxane oligomer of formula XI
• wherein m is an integer from 2 to 20;
• R1 in each occurrence is chosen independently for each siloxane unit from CH3, OCH3, OCH2CH3, vinyl, and a further unit of [—O—SiR12—]q-OCH3, wherein q is an integer from 2 to 20;
• in the presence of a noble metal hydrosilation catalyst,
• with the provisos that at least one of R1 must be a vinyl containing unit, said vinyl siloxane oligomer having a viscosity from 10 centipoise to 10,000 centipoise, and a ratio of alkoxy groups to Si atoms in a range from 0.004:1 to 1.5:1.

A method for producing a polymer encapsulated light emitting diode (LED) comprising:

• providing a vinyl siloxane oligomer having a plurality of vinyl functionalities and a viscosity from 10 centipoise to 10,000 centipoise at 25° C.;
• providing a noble metal hydrosilation catalyst;
• and
• providing a cyclosiloxane oligomer selected from structure I, structure II, structure III, structure IV, structure V, structure VI, and structure VII:
• wherein R in each occurrence is chosen independently from H, a methyl, an alkyl, and a haloalkyl, with the proviso that at least two of R must be H;
• combining said vinyl siloxane oligomer, said noble metal hydrosilation catalyst, and said cyclosiloxane oligomer to give a mixture;
• applying said mixture to a LED;
• and
• curing said mixture to form a polymer encapsulated LED.