Siloxane resin compositions

Abstract

Addition curable silicone resin compositions have excellent processing characteristics, and can be used to encapsulate electrical and electronic devices.

Claims

1. A compositions comprising: (A) at least one organopolysiloxane comprising at least 3 units of the formula
R.sup.1.sub.aR.sup.2.sub.bR.sup.3.sub.cH.sub.d(RO).sub.eSiO.sub.(4-a-b-c-d-e)/2(I), where R.sup.1 each independently are monovalent, SiC-bonded, optionally halogen- or cyano-substituted hydrocarbyl moieties with aliphatic carbon-carbon multiple bonding, R.sup.2 each independently are monovalent, SiC-bonded, optionally halogen- or cyano-substituted, saturated hydrocarbyl moieties, R.sup.3 each independently are monovalent SiC-bonded aromatic moieties, R each independently are hydrogen or monovalent, optionally substituted hydrocarbyl moieties which are optionally interrupted by heteroatoms, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, c is 0, 1, 2 or 3, d is 0, 1 or 2, and e is 0, 1 or 2, with the proviso that the a+b+c+d+e sum is not more than 3, the sum total of Si-bonded hydrogen atoms and R.sup.1 moieties per molecule is at least 3, the a+b+c+d sum is equal to 0 or 1 in at least 10 mol % of the units of formula (I), c is other than 0 in at least one unit, and the ratio of Si-bonded hydrogen atoms to Si-bonded R.sup.1 moieties in the siloxane (A) is from 0.1 to 9, optionally (B) organopolysiloxanes comprising units of the formula
R.sup.4.sub.fR.sup.5.sub.gR.sup.6.sub.h(R.sup.7O).sub.tSiO.sub.(4-f-g-h-i)/2(VI), where R.sup.4 each independently are monovalent, SiC-bonded, optionally halogen- or cyano-substituted, hydrocarbyl moieties with aliphatic carbon-carbon multiple bonding, R.sup.5 each independently are monovalent, SiC-bonded, optionally halogen- or cyano-substituted, saturated hydrocarbyl moieties, R.sup.6 each independently are monovalent SiC-bonded aromatic moieties, R.sup.7 each independently are hydrogen or monovalent, optionally substituted hydrocarbyl moieties, which are optionally interrupted by heteroatoms, f is 0, 1, 2 or 3, g is 0, 1, 2 or 3, h is 0, 1 or 2, i is 0 or 1, with the proviso that the f+g+h+i sum is not more than 3, siloxanes (B) have at least two R.sup.4 moieties per molecule, the f+g+h+i sum is equal to 0 or 1 in not more than 20 mol % of the units of formula (VI) and h is other than 0 in at least one unit of formula (VI), (C) at least one organopolysiloxane comprising units of the formula
R.sup.8.sub.kR.sup.9.sub.lR.sup.10.sub.m(R.sup.11O).sub.nSiO.sub.(4-k-l-m-n)/2(X), where R.sup.8 each independently are monovalent, SiC-bonded, optionally halogen- or cyano-substituted, hydrocarbyl moieties with aliphatic carbon-carbon multiple bonding, R.sup.9 each independently are monovalent, SiC-bonded, optionally halogen- or cyano-substituted, saturated hydrocarbyl moieties, R.sup.10 each independently are monovalent SiC-bonded aromatic moieties, R.sup.11 each independently are hydrogen or monovalent, optionally substituted hydrocarbyl moieties, which are optionally interrupted by heteroatoms, k is 0, 1, 2 or 3, l is 0, 1, 2 or 3, m is 0, 1 or 2, and n is 0 or 1, with the proviso that the k+l+m+n sum is not more than 3, siloxanes (C) have at least two R.sup.8 moieties per molecule, the k+l+m+n sum is equal to 0 or 1 in at least 10 mol % of the units of formula (X) and m is other than 0 in at least one unit of formula (X), and optionally, (D) a catalyst which promotes the addition of Si-bonded hydrogen onto aliphatic carbon-carbon multiple bonds.

2. The composition of claim 1, wherein siloxane(s) (A) comprise siloxanes having at least 3 units selected from the group consisting of the formulae
R.sup.1.sub.aR.sup.2.sub.bR.sup.3.sub.cH.sub.d(RO).sub.eSiO.sub.1/2 where (a+b+c+d+e)=3(II),
R.sup.2.sub.bR.sup.3.sub.c(RO)SiO.sub.2/2 where (b+c)=1(IIIa),
R.sup.2.sub.bR.sup.3.sub.cSiO.sub.2/2 where (b+c)=2(IIIb),
R.sup.2.sub.bR.sup.3.sub.c(RO).sub.eSiO.sub.3/2 where (b+c+e)=1(IV), and
SiO.sub.4/2(V), where R, R.sup.1, R.sup.2, R.sup.3, a, b, c, d and e are each as defined above, with the proviso that not more than 25 mol % of the units in the siloxanes (A) are of formula (IIIb), the sum total of Si-bonded hydrogen atoms and R.sup.1 moieties per molecule is at least 3, at least one R.sup.3 moiety is present per molecule, and at least one unit of formula (IV) and/or (V) is present.

3. The composition of claim 1, wherein component (C) comprises siloxanes consisting of units selected from the group consisting of:
R.sup.8.sub.kR.sup.9.sub.lR.sup.10.sub.m(R.sup.11O).sub.nSiO.sub.1/2 where (k+l+m+n)=3(XI),
R.sup.9.sub.lR.sup.10.sub.m(R.sup.11O)SiO.sub.2/2 where (l+m)=1(XIIa),
R.sup.9.sub.lR.sup.10.sub.mSiO.sub.2/2 where (l+m)=2(XIIb),
R.sup.9.sub.lR.sup.10.sub.m(R.sup.11O).sub.nSiO.sub.3/2 where (l+m+n)=1(XIII), and
SiO.sub.4/2(V) where R.sup.8, R.sup.9, R.sup.10, R.sup.11, k, l, m and n are each as defined above, with the proviso that siloxanes (C) have at least two R.sup.8 moieties per molecule, at least one R.sup.10 moiety is present per molecule, and at least one unit of formula (XIII) and/or (V) is present.

4. The composition of claim 2, wherein component (C) comprises siloxanes consisting of units selected from the group consisting of:
R.sup.8.sub.kR.sup.9.sub.lR.sup.10.sub.m(R.sup.11O).sub.nSiO.sub.1/2 where (k+l+m+n)=3(XI),
R.sup.9.sub.lR.sup.10.sub.m(R.sup.11O)SiO.sub.2/2 where (l+m)=1(XIIa),
R.sup.9.sub.lR.sup.10.sub.mSiO.sub.2/2 where (l+m)=2(XIIb),
R.sup.9.sub.lR.sup.10.sub.m(R.sup.11O).sub.nSiO.sub.3/2 where (l+m+n)=1(XIII), and
SiO.sub.4/2(V) where R.sup.8, R.sup.9, R.sup.10, R.sup.11, k, l, m and n are each as defined above, with the proviso that siloxanes (C) have at least two R.sup.8 moieties per molecule, at least one R.sup.10 moiety is present per molecule, and at least one unit of formula (XIII) and/or (V) is present.

5. The composition of claim 1, comprising from 1 to 200 parts by weight of siloxane (C), based on 100 parts by weight of component (A).

6. The composition of claim 2, comprising from 1 to 200 parts by weight of siloxane (C), based on 100 parts by weight of component (A).

7. The composition of claim 3, comprising from 1 to 200 parts by weight of siloxane (C), based on 100 parts by weight of component (A).

8. The composition of claim 1, comprising: (A) siloxanes comprising units of formula (I), optionally (B) siloxanes comprising units of formula (VI), (C) siloxanes comprising units of formula (X), (D) a catalyst which promotes the addition of Si-bonded hydrogen onto aliphatic carbon-carbon multiple bonds, optionally (E) fillers, optionally (F) adhesion promoters, optionally (G) inhibitors, optionally (H) plasticizers, optionally (K) additives, and optionally (L) solvents.

9. The composition of claim 1, comprising: (A) siloxanes comprising units of formula (I), optionally (B) siloxanes comprising units of formula (VI), (C) siloxanes comprising units of formula (X), (D) a catalyst which promotes the addition of Si-bonded hydrogen onto aliphatic carbon-carbon multiple bonds, optionally (E) fillers, (F) adhesion promoters, optionally (G) inhibitors, optionally (H) plasticizers, optionally (K) additives, and optionally (L) solvents.

10. A process for producing a composition of claim 1, comprising mixing the individual components in arbitrary order.

11. A shaped article obtained by crosslinking a composition of claim 1.

12. The shaped article of claim 11, which is a coating, encapsulation, or lens.

13. In a process for encapsulation of electrical or electronic components, the improvement comprising encapsulating with a composition of claim 1.

14. In a process for the manufacture of devices containing LEDs, the improvement comprising encapsulating at least one LED with a composition of claim 1.

Description

EXAMPLES

(1) The formulations are prepared as follows in the examples which follow:

(2) The formulations are prepared by preparing homogeneous mixtures of the particular reported components using a DAC 150 FV type Speedmixer from Hauschild and subsequent degassing of the sample with an oil diffusion pump or on a planetary mixer from Thinky Corporation, Japan, type AWATORI RENTARO Model ARV-310 by simultaneous evacuation.

(3) Unless otherwise stated, the degassed mixtures are poured into open steel moulds having a diameter of 35 mm and a height of 6 mm and allowed to vulcanize at 150 C. in a circulating air drying cabinet. The vulcanization period is reported with the particular formulation.

Example 1

(4) In a planetary mixer, 80 parts of resin (A2) are mixed with 20 parts of resin (C1) and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 1 h. The vulcanizate has a Shore D hardness of 58.

Example 2

(5) In a planetary mixer, 45 parts of resin (A3) are mixed with 55 parts of resin (C1) and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 1 h. The vulcanizate has a Shore D hardness of 65.

Example 3

(6) In a planetary mixer, 35 parts of resin (A5) are mixed with 65 parts of resin (C1) and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 1 h. The vulcanizate has a Shore D hardness of 70.

Example 4

(7) In a planetary mixer, 60 parts of resin (A2) are mixed with 40 parts of resin (C1) and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 1 h. The vulcanizate has a Shore D hardness of 30.

Example 5

(8) In a planetary mixer, 70 parts of resin (A2) are mixed with 30 parts of resin (C3) and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 1 h. The vulcanizate has a Shore D hardness of 45.

Example 6

(9) In a planetary mixer, 60 parts of resin (A2) are mixed with 30 parts of resin (C1), 10 parts of a vinyl-terminated polydimethylphenylmethylsiloxane having the composition (Me.sub.2ViSiO.sub.1/2).sub.2(MePhSiO.sub.2/2).sub.60(Me.sub.2SiO.sub.2/2).sub.12 (refractive index n.sub.D.sup.25=1.538, viscosity =7800 mPas) and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 1 h. The vulcanizate has a Shore D hardness of 40.

Example 7

(10) In a planetary mixer, 60 parts of resin (A2) are mixed with 40 parts of resin (C1) and 0.002 part (based on platinum) of methylcyclopentadienyltrimethylplatinum(IV). The mixture is degassed, poured into an open steel mould having a diameter of 35 mm and a height of 6 mm and irradiated with an iron irradiator (D-bulb) from Hanle, Grfelfing, Germany at 140 mW/cm.sup.2 for 15 seconds. The vulcanizate has a Shore D hardness of 50.

Example 8

(11) In a planetary mixer, 60 parts of resin (A2) are mixed with 30 parts of resin (C1), 10 parts of a vinyl-terminated polydimethylphenylmethylsiloxane having the composition (Me.sub.2ViSiO.sub.1/2).sub.2(MePhSiO.sub.2/2).sub.60(Me.sub.2SiO.sub.2/2).sub.12 (refractive index n.sub.D.sup.25=1.538, viscosity =7800 mPas), 0.5 part of (3-glycidoxypropyl)trimethoxysilane and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 1 h. The vulcanizate has a Shore D hardness of 40.

Comparative Example 1

(12) In a planetary mixer, 70 parts of resin (C2) are mixed with 10 parts of a vinyl-terminated polydimethylphenylmethylsiloxane having the composition (Me.sub.2ViSiO.sub.1/2).sub.2(MePhSiO.sub.2/2).sub.60(Me.sub.2SiO.sub.2/2).sub.12 (refractive index n.sub.D.sup.25=1.538, viscosity 1=7800 mPas), 20 parts of 1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 2 h. The vulcanizate has a Shore A hardness of 60.

Comparative Example 2

(13) In a planetary mixer, 65 parts of resin (C2) are mixed with 35 parts of 1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 4 h. The vulcanizate has a Shore D hardness of 38.

Example 9

(14) In a planetary mixer, 50 parts of resin (A2) are mixed with 50 parts of resin (C1), 0.5 part of (3-glycidoxypropyl)trimethoxysilane and 0.0002 part (based on platinum) of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. The mixture is vulcanized at 150 C. for 1 h. The vulcanizate has a Shore D hardness of 68.