One-component, storage-stable, UV-crosslinkable organosiloxane composition

Abstract

The invention relates to the use as a coating or impregnating agent of an organosiloxane composition comprising a) 20 to 98.999989 wt % of at least one polyorganosiloxane comprising at least two alkenyl or alkynyl groups, as component A; b) 0.1 to 30 wt % of at least one linear or branched polyorganosiloxane comprising at least 3 Si—H groups, as component B; c) 0.000001 to 1 wt % of at least one UV-activatable, platinum-containing hydrosilylation catalyst, as component C; d) 0.00001 to 5 wt % of at least one alkynol of the general formula (I), where R.sup.1, R.sup.2 and R.sup.3 independently of one another are selected from H, C.sub.1-C.sub.6 alkyl and C.sub.3-C.sub.6 cycloalkyl; or R.sup.1 is selected from H, C.sub.1-C.sub.6 alkyl and C.sub.3-C.sub.6 cycloalkyl, and R.sup.2 and R.sup.3 are connected to one another and form a 3- to 8-membered ring, as component D; e) 0 to 79.899989 wt % of one or more polyorganosiloxanes comprising two terminal Si—H groups or one terminal Si—H group and one terminal alkenyl group, as component E; f) 0 to 20 wt % of one or more epoxy organosiloxanes, as component F; g) 0 to 5 wt % of one or more organosiloxanes, different from component A and having 1 to 5 Si atoms, and comprising at least two alkenyl groups, as component G; h) 0 to 79.899989 wt % of one or more silsesquioxanes, as component H; and i) 0 to 75 wt % of one or more additives, as component I; where the sum of components A to I is 100 wt %. ##STR00001##

Claims

1. A process for applying a protective compound to an electrical or electronic component, the process comprising: providing a one-component organosiloxane composition comprising: a) 20 to 98.999989 wt % of at least one linear or branched polyorganosiloxane comprising at least two alkenyl or alkynyl groups, as component A; b) 0.1 to 30 wt % of at least one linear or branched polyorganosiloxane comprising at least 3 Si—H groups, as component B; c) 0.000001 to 1 wt % of at least one UV-activatable, platinum-containing hydrosilylation catalyst, as component C; d) at least one alkynol of the general formula (I) present in an amount such that the viscosity of the one-component organosiloxane composition changes less than 10% when stored for at least three months at room temperature in a lightproof container but permitting curing of the composition upon UV irradiation, ##STR00006## where R.sup.1, R.sup.2 and R.sup.3 independently of one another are selected from H, C1-C6 alkyl and substituted or unsubstituted C3-C6 cycloalkyl; or R.sup.1 is selected from H, C1-C6 alkyl and substituted or unsubstituted C3-C6 cycloalkyl, and R.sup.2 and R.sup.3 are connected to one another and form a 3- to 8-membered ring which may be substituted by one or more C1-C3 alkyl groups, as component D, wherein the amount of the at least one alkynol inhibits the catalyst; e) 0 to 79.899989 wt % of one or more polyorganosiloxanes comprising two terminal Si—H groups or one terminal Si—H group and one terminal alkenyl group, as component E; f) 0 to 20 wt % of one or more epoxy organosiloxanes, as component F; g) 0 to 5 wt % of one or more acyclic or cyclic organosiloxanes, different from component A and having 1 to 5 Si atoms, and comprising at least two alkenyl groups, as component G; h) 0 to 79.899989 wt % of one or more silsesquioxanes, as component H; and i) 0 to 75 wt % of one or more additives, as component I; where the sum of components A to I is 100 wt %; applying the one-component organosiloxane composition to an electrical or electronic component, and irradiating the one-component organosiloxane composition with UV light; wherein the inhibition of the catalyst is lifted by means of UV radiation.

2. The process according to claim 1, wherein component A comprises at least one linear polyorganosiloxane of the general formula (II), ##STR00007## where R.sup.8 independently is selected from C.sub.1-C.sub.6 alkyl; and n is a number from 6 to 1000.

3. The process according to claim 1, wherein component B is a linear polydimethylsiloxane comprising at least 3 Si—H groups.

4. The process according to claim 1, wherein component C is trimethyl(methylcyclopentadienyl)platinum.

5. The process according to claim 1, wherein component D is an alkynol of the general formula (I) where R.sup.1 is H, R.sup.2 is methyl and R.sup.3 is selected from C.sub.1-C.sub.6 alkyl, or R.sup.2 and R.sup.3 are connected to one another and form a cyclohexane ring.

6. The process according to claim 5, component D is 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, or 1-ethynyl-1-cyclohexanol.

7. The process according to claim 1, wherein the UV-activatable, platinum-containing hydrosilylation catalyst comprises an optionally substituted cyclopentadienyl group as a ligand.

8. An electrical or electronic component having an organosiloxane coating, wherein the coating is obtained through curing a one-component organosiloxane composition comprising: a) 20 to 98.999989 wt % of at least one linear or branched polyorganosiloxane comprising at least two alkenyl or alkynyl groups, as component A; b) 0.1 to 30 wt % of at least one linear or branched polyorganosiloxane comprising at least 3 Si—H groups, as component B; c) 0.000001 to 1 wt % of at least one UV-activatable, platinum-containing hydrosilylation catalyst, as component C; d) at least one alkynol of the general formula (I) present in an amount such that the viscosity of the one-component organosiloxane composition changes less than 10% when stored for at least three months at room temperature in a lightproof container but permitting curing of the composition upon UV irradiation, ##STR00008## where R.sup.1, R.sup.2 and R.sup.3 independently of one another are selected from H, C1-C6 alkyl and substituted or unsubstituted C3-C6 cycloalkyl; or R.sup.1 is selected from H, C1-C6 alkyl and substituted or unsubstituted C3-C6 cycloalkyl, and R.sup.2 and R.sup.3 are connected to one another and form a 3- to 8-membered ring which may be substituted by one or more C1-C3 alkyl groups, as component D; e) 0 to 79.899989 wt % of one or more polyorganosiloxanes comprising two terminal Si—H groups or one terminal Si—H group and one terminal alkenyl group, as component E; f) 0 to 20 wt % of one or more epoxy organosiloxanes, as component F; g) 0 to 5 wt % of one or more acyclic or cyclic organosiloxanes, different from component A and having 1 to 5 Si atoms, and comprising at least two alkenyl groups, as component G; h) 0 to 79.899989 wt % of one or more silsesquioxanes, as component H; and i) 0 to 75 wt % of one or more additives, as component I; where the sum of components A to I is 100 wt %.

9. The electrical or electronic component according to claim 8 wherein the one-component organosiloxane composition is cured using UV-radiation.

10. The electrical or electronic component according to claim 8, wherein the electrical or electronic component includes one or more of an electrical wire, an electrical winding, a circuit board, or an electronic assembly.

11. An electrical or electronic component impregnated in an organosiloxane compound, wherein the compound is obtained through curing a one-component organosiloxane composition comprising: a) 20 to 98.999989 wt % of at least one linear or branched polyorganosiloxane comprising at least two alkenyl or alkynyl groups, as component A; b) 0.1 to 30 wt % of at least one linear or branched polyorganosiloxane comprising at least 3 Si—H groups, as component B; c) 0.000001 to 1 wt % of at least one UV-activatable, platinum-containing hydrosilylation catalyst, as component C; d) at least one alkynol of the general formula (I) present in an amount such that the viscosity of the one-component organosiloxane composition changes less than 10% when stored for at least three months at room temperature in a lightproof container but permitting curing of the composition upon UV irradiation, ##STR00009## where R.sup.1, R.sup.2 and R.sup.3 independently of one another are selected from H, C1-C6 alkyl and substituted or unsubstituted C3-C6 cycloalkyl; or R.sup.1 is selected from H, C1-C6 alkyl and substituted or unsubstituted C3-C6 cycloalkyl, and R.sup.2 and R.sup.3 are connected to one another and form a 3- to 8-membered ring which may be substituted by one or more C1-C3 alkyl groups, as component D; e) 0 to 79.899989 wt % of one or more polyorganosiloxanes comprising two terminal Si—H groups or one terminal Si—H group and one terminal alkenyl group, as component E; f) 0 to 20 wt % of one or more epoxy organosiloxanes, as component F; g) 0 to 5 wt % of one or more acyclic or cyclic organosiloxanes, different from component A and having 1 to 5 Si atoms, and comprising at least two alkenyl groups, as component G; h) 0 to 79.899989 wt % of one or more silsesquioxanes, as component H; and i) 0 to 75 wt % of one or more additives, as component I; where the sum of components A to I is 100 wt %.

12. A one-component storage stable organosiloxane composition having a viscosity equal to or smaller than 5000 mPa.Math.s, comprising a) 20 to 98.999989 wt % of at least one linear or branched polyorganosiloxane comprising at least two alkenyl or alkynyl groups, as component A; b) 0.1 to 30 wt % of at least one linear or branched polyorganosiloxane comprising at least 3 Si—H groups, as component B; c) 0.000001 to 1 wt % of at least one UV-activatable, platinum-containing hydrosilylation catalyst, as component C; d) at least one alkynol of the general formula (I) present in an amount such that the viscosity of the one-component organosiloxane composition changes less than 10% when stored for at least three months at room temperature in a lightproof container but permitting curing of the composition upon UV irradiation, ##STR00010## where R.sup.1, R.sup.2 and R.sup.3 independently of one another are selected from H, C1-C6 alkyl and substituted or unsubstituted C3-C6 cycloalkyl; or R.sup.1 is selected from H, C1-C6 alkyl and substituted or unsubstituted C3-C6 cycloalkyl, and R.sup.2 and R.sup.3 are connected to one another and form a 3- to 8-membered ring which may be substituted by one or more C1-C3 alkyl groups, as component D, wherein the amount of the at least one alkynol inhibits the catalyst; e) 0 to 79.899989 wt % of one or more polyorganosiloxanes comprising two terminal Si—H groups or one terminal Si—H group and one terminal alkenyl group, as component E; f) 0 to 20 wt % of one or more epoxy organosiloxanes, as component F; g) 0 to 5 wt % of one or more acyclic or cyclic organosiloxanes, different from component A and having 1 to 5 Si atoms, and comprising at least two alkenyl groups, as component G; h) 0 to 79.899989 wt % of one or more silsesquioxanes, as component H; and i) 0 to 75 wt % of one or more additives, as component I; where the sum of components A to I is 100 wt %.

13. A process for applying a protective compound to an electrical or electronic component, the process comprising: providing the one-component organosiloxane composition of claim 12, applying the one-component organosiloxane composition to an electrical or electronic component, and irradiating the one-component organosiloxane composition with UV light, wherein the inhibition of the catalyst is lifted by means of UV radiation.

Description

EXAMPLES

(1) The examples are intended to elucidate the present invention, but in no way impose any limitation thereon.

(2) The formulations were mixed using a Hauschild SpeedMixer of type DAC 150.1 FVZ-K.

(3) The crosslinking was initiated by irradiation with an iron-doped mercury emitter. The UV dose was 6000 mJ/cm.sup.2.

(4) The Shore A hardness was measured using a commercial Shore A measuring instrument.

(5) The rheological parameters, such as the viscosity of the composition, were measured using an Anton Paar Type MCR-302 Rheometer. The measurements were done at 25° C. in accordance with DIN 53019 with a concentric cylinder type B-CC25 (Z3) at a shear gradient D=10 s.sup.−1.

Example 1

(6) A formulation of 596 parts of a divinylpolydimethylsiloxane of viscosity 200 mPa.Math.s (component A), 46.1 parts of a polydimethylsiloxane having an Si—H fraction of 7 mmol/g and at least 3 Si—H units per molecule (component B), 0.03 part of trimethyl(methylcyclopentadienyl)platinum (component C), 0.019 part of 1-ethynyl-1-cyclohexanol (component D), 329.5 parts of a linear polydimethylsiloxane having terminal Si—H groups (component E), 13 parts of 3-glycidyloxypropyltrimethoxysilane (component F), 0.1 part of 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole) (component J, fluorescer) and 10 parts of a coated fumed silica (component J, rheological assistant) is thoroughly mixed.

(7) The mixture can be stored for three months at room temperature and within this time can be crosslinked within a few seconds by UV irradiation with a dose of 6000 mJ/cm.sup.2. Directly after irradiation, the formulation forms a solid which continues to increase in hardness somewhat within one hour after irradiation. The viscosity of the unvulcanized mixture is 500 mPa.Math.s at 25° C. and is dependent on shear rate. The Shore A hardness of the vulcanized mixture is 10.

Example 2

(8) A formulation of 586 parts of a divinylpolydimethylsiloxane of viscosity 200 mPa.Math.s (component A), 46.1 parts of a polydimethylsiloxane having an Si—H fraction of 7 mmol/g and at least 3 Si—H units per molecule (component B), 0.03 part of trimethyl(methylcyclopentadienyl)platinum (component C), 0.019 part of 1-ethynyl-1-cyclohexanol (component D), 329.5 parts of a linear polydimethylsiloxane having terminal Si—H groups (component E), 13 parts of 3-glycidyloxypropyltrimethoxysilane (component F), 10 parts of methylvinylcyclotetrasiloxane (component G), 0.1 part of 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole) (component J, fluorescer) and 10 parts of a coated fumed silica (component J, rheological assistant) is thoroughly mixed.

(9) The mixture can be stored for three months at room temperature and within this time can be crosslinked within a few seconds by UV irradiation with a dose of 6000 mJ/cm.sup.2. After irradiation, the formulation forms a solid over a period of several minutes. The viscosity of the unvulcanized mixture is 500 mPa.Math.s at 25° C. and is dependent on shear rate. The Shore A hardness of the vulcanized mixture is 20.

Example 3

(10) A formulation of 406.8 parts of a divinylpolydimethylsiloxane of viscosity 200 mPa.Math.s (component A), 300 parts of a divinylpolydimethylsiloxane of viscosity 1000 mPa.Math.s (component A), 30 parts of a polydimethylsiloxane having an Si—H fraction of 7 mmol/g and at least 3 Si—H units per molecule (component B), 0.03 part of trimethyl(methylcyclopentadienyl)platinum (component C), 0.019 part of 3,5-dimethyl-1-hexyn-3-ol (component D), 150 parts of a linear polydimethylsiloxane having terminal Si—H groups (component E), 13 parts of 3-glycidyloxypropyltrimethoxysilane (component F), 100 parts of a VQM resin (component H) and 0.1 part of 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole) (component J, fluorescer) is thoroughly mixed.

(11) The mixture can be stored for three months at room temperature and within this time can be crosslinked within a few seconds by UV irradiation with a dose of 6000 mJ/cm.sup.2. After irradiation, the formulation forms a solid which continues to increase in hardness somewhat within one hour after irradiation.

Example 4

(12) A formulation of 596 parts of a divinylpolydimethylsiloxane of viscosity 200 mPa.Math.s (component A), 46.1 parts of a polydimethylsiloxane having an Si—H fraction of 7 mmol/g and at least 3 Si—H units per molecule (component B), 0.03 part of trimethyl(methylcyclopentadienyl)platinum (component C), 0.02 part of 1-ethynylcyclohexane-1-ol (component D), 330 parts of a linear polydimethylsiloxane having terminal Si—H groups (component E), 10 parts of coated pyrogenic silicon dioxide (component J), and 0.1 part of 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole) (component J, fluorescer) is thoroughly mixed.

(13) The mixture can be stored for three months at room temperature and within this time can be crosslinked within a few seconds by UV irradiation with a dose of 6000 mJ/cm.sup.2. After irradiation, the formulation forms a solid which continues to increase in hardness somewhat within one hour after irradiation.

Example 5

(14) A formulation of 2400 parts of a divinylpolydimethylsiloxane of viscosity 1000 mPa.Math.s, 11.25 parts of a polydimethylsiloxane having an Si—H fraction of 4.3 mmol/g and at least 3 Si—H units per molecule (component B), 75 parts of a polydimethylsiloxane having an Si—H fraction of 0.9 mmol/g, 0.08 part of trimethyl(methylcyclopentadienyl)platinum (component C), and 0.05 part of 1-ethynylcyclohexane-1-ol (component D) is thoroughly mixed.

(15) The mixture can be stored for three months at room temperature and within this time can be crosslinked within a few seconds by UV irradiation with a dose of 6000 mJ/cm.sup.2. After irradiation, the formulation forms a solid which continues to increase in hardness somewhat within one hour after irradiation.