JPS587452A - Hardenable siloxane composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to unique siloxane compositions that cure to form dielectric silicone gels.

In particular, the compositions disclosed herein are capable of curing readily at ambient or elevated temperatures and withstanding cryogenic temperatures (approximately -120°C) without deleterious effects on the physical properties of the del and its low temperature properties. A silicone pill can be made to produce 4I
Contains permissible ingredients.

The primary use of gels formulated according to the present invention is in dielectric injection gels. The use of silicone potting materials to encapsulate electrical components is well documented.

U.S. Pat. No. 3,436,366, issued April 1, 1969, to Modia K. Methods of using silicone materials are described. Modie 4I also describes the possibility of polyols having only methyl and vinyl substituents to formulate dielectric potting materials with nosiloxanes. However, these substituents are arranged in such a way as to promote a large amount of cross-linking to produce sufficient tear strength. In particular, Modio combines methylvinylsiloxane units and Si
It is taught to use organopolysquinanes having O units. Both of these units promote crosslinking to a high degree and yield products that have little in common with the flexible gels of the present invention. Sara K.

The Moa1O material has a unique low
1411.

US Pat. No. 5,020,260, issued February 6, 1962 to K. Melson K., is possibly related to the present invention. Example 10 thereof describes a silicone delta formulated from a si-tetraxane copolymer having only methyl and vinyl substituents.

More precisely, the 1esson patent is (1) M6g8
10.

86.95 parts by weight of a copolymer consisting of MeVi102 and MeB810J5 and (2) Me2810,
A silicone potting gel is formulated by reacting a blend of 8.27 parts by weight of a copolymer consisting of M6B101.1s and M@1B10.5 with 4.78 parts by weight of an organohydrocloxane crosslinker in the presence of a platinum catalyst. teaching the method. Code [Me J is r −0Hs
represents the J group, and the symbol “vl” is “-OH,,ou,J
represents a group.

The silicone injection gel obtained from the N.1JOn formulation yields a dielectric silicone gel, but what proportion of units and intermediate % are used? A unit with el functionality (Me
Due to the presence of Vi1310) it has no structural properties and does not exhibit the low temperature stability that the siloxandals produced according to the invention have.

U.S. Patent No. 3,3 issued January 22, 1968
No. 61,714 describes certain "<S-shaped" polymers and "star-shaped" polymers with low-temperature properties.
Poly! −Disclosed. These polymers have the general formula (however, R and R1 are monovalent hydrocarbon groups, R1
is a monovalent hydrocarbon group or a substituted monovalent hydrocarbon group, n is 0 to 25, and m is 1 to 21.

W is 0 υ very hot, 2' is hydrogen or Its81-).

2 is a non-random I remer with hydrogen (R3810-). Omi・tans
ki teaches that it is possible to obtain elastomers and liquids exhibiting low temperature properties cured with organic peroxides.

Noting the properties and limitations of known and described silicone potting materials, we attempted to formulate siloxandels from siloxane polymers with only methyl and vinyl substituents. However, these known units have been combined to provide novel polymerizable compositions that cure rapidly at ambient or elevated temperatures and maintain their properties at cryogenic temperatures.

Therefore, we (at essentially, (aHr3), sio 80~
96.5 molti, 0H581011Js2.0 = 1
0.0 mol-s (OHi)s810o, sl, 25~
6.0 molti and (OHs)g(OHs-OR)Si
Polyorganosiloxane characterized in that it consists of Oo, aO025 to 4.0 mole: (t) more than one silicon-bonded hydrogen atom per molecule and less than one silicon-bonded hydrogen atom per silicon atom; an organohydrogensiloxane having an aliiso group selected from the group consisting of an alkyl group of 1 to 6 carbon atoms, phenyl, and 3,3,3-) IJ fluorozorozole, An average of 0.2 to 5.0 moles of silicon-bonded hydrogen per mole of silicon-bonded vinyl is 4
A curable siloxane composition consisting of a homogeneous mixture consisting essentially of (c) a platinum catalyst has been developed.

The Siloxa/Del of the present invention is essentially a defined polyorganosiloxane cured with an organohydrogensiloxane crosslinker in the presence of a platinum catalyst.

Polyorganosiloxane y is mainly composed of dimethylsiloxane units (Me2SiO).

The presence of this particular unit can vary from 80 to 96.5 moles of the total siloxane units in the I remer, but optimal results indicate that the dimethylsiloxane units are 90 to 96.5 moles of the total siloxane units in the polymer.
Achieved when it consists of more than 100%.

The second unit of the polyorganosiloxane is monomethylsiloxane (Me8101J). This unit is 11J
Good results were achieved using M68101.8 in an amount equal to 3 to 6 moles of polymer, although accounting for 2 to 10.0 moles of total siloxane units in the polymer.

Me8101. The s unit is essential because it introduces unique low temperature properties to the siloxane polymer. At temperatures below -υ℃, it is a hard crystalline phase. Siloxane 1 The monomethylsiloxane units randomly arranged along the polymer chain make it possible to remove the crystalline phase from the polymer.

Therefore, this new siloxane polymer remains in the amorphous phase upon cooling until it reaches the glass transition temperature (7g) -123°C. At this temperature the siloxane polymer transforms into a hard glass phase.

The third unit is a trimethylsiloxane unit (Me3810
6J). This calyx merely acts as a terminal terminator for the polytwo chain. This unit is 1 of the total organosiloxane
．． Although it is possible to use it in a range of 25 to 6.0 mol, it is preferably used in a range of 2.5 to 5 mol of I-limer.

The final units of the siloxane primer are vinyl-containing siloxane units. Dimethylvinylsiloxane (M@2Vi81) in which this unit is characterized by a vinyl functionality in the terminal position
0,5) is essential. The main reason for using a terminal vinyl group at 9 instead of the intermediate vinyl group (ie, MeVi810) is to increase the curing rate.

The rate constant of hyrosilylation is doubled by changing the intermediate vinyl group to the terminal vinyl group K. The terminal vinyl units also act as conjugate end cappers with the trimethylsiloxane units described above.

The terminal vinyl siloxane units can account for 0.25 to 4 moles of the total organosiloxane units in the polymer.

Since the terminal V-nyl unit and the trimethylsiloxane unit are the end caps of the organosiloxane polymer, it is essential that the total triorganosiloxane unit is less than 10 moles of the total chloroxane.

A preferred curable whitening composition is polyorgan/silicone.
Kisanka essential K (oH3) gsio 87-94 mole-1OH38101,83-6 mo, II/9G,
(OHs)3Elioo, 212.5-5 moles 11! and (OH3)l(OHI-wOH)810QJO15
~2.0 mol], especially the polyorganosiloxane (OH3) IBlo 92-94 mol H58101, 53-4 mol 1(OH3) 5810
QJ 2.5-3 molmol and (aH5) g (0g2!
aH) tiio6.11 consists of 0.5 to 1 mole.

The polyorganosiloxane is reacted with a suitable crosslinking agent in the presence of a polymeric catalyst and cured to form a polymeric material. A suitable crosslinking agent for the 9-polyorganosiloxane used in this invention is a stone organohydrogensiloxane characterized by a reactive moiety=81H. The required crosslinking agent has an average of more than one silicon-bonded hydrogen atom per molecule and no more than one silicon-bonded hydrogen atom per silicon atom. Other electrolytic groups on the silicon atom include 1 group and 1 to 6 carbon atoms.
Alkyl groups having phenyl and 3, ! 1.3-
An organic group typically selected from the group consisting of trifluorozorozole. The amount of crosslinking agent used is gM81H0
, 2-5.0 moles per ==81 Vi1 moles. 0.5/1~0.95
It has been found that a ratio in the range of 71 is very satisfactory, as it has at least two molecules per molecule! 8 is a result of the preferred crosslinking agent functionality containing the iH component.

Examples of organohydrogensiloxane compounds that can be used in accordance with the present invention are 1 containing one silicon-bonded methyl group and one silicon-bonded hydrogen atom (per silicon atom);
3,5.7-titramethylcyclotetrasiloxane. This cyclic polymer is made by hydrolysis of MeH81Cjm. Other crosslinking agents are dimethylhydrogen siloxane-terminated polydimethylsiloxane KM@lE
ll (0M681) Engineering H (note that the ink numbers are from 1 to 30). This polymer is plate, 81Cj, 81U,
Co-hydrolysis of or HMeg81081Ml! It is produced by equilibration of IIH and (M@1810)4. Other types of crosslinking compositions include polymers of dimethylsiloxane units, methylhydrogensiloxane units, and trimethylsiloxane units, and have a molecular weight of at least 4 to 20 units.
It contains one or more silicon atoms.

This composition is M@3810 (IJaH810)! 81M
It is produced by equilibration of 55 and (M@2810)4.

Preferred organohydrogensiloxanes have the formula %formula%) (However, the number of stones is 5 to 20.)

This organohydrogensiloxane is used in the above polyol crosslinking of the chloroxane under platinum catalyst to obtain the polyol and constitutes a preferred embodiment of the invention. The most preferred ratio of silicon-bonded hydrogen to silicon-bonded vinyl is 0.5
71 to 0.9571.

The platinum catalysts used in this invention include all known platinum catalysts effective for catalyzing the reaction between silicon-bonded hydrogen and vinyl groups. These substances were released on February 11, 1958.
U.S. Patent No. 2,82 issued to 8psier et al.
No. 5,218, and U.S. Pat. No. 3,419, issued December 31, 1968.
, K. Willing K., 593.

Also, U.S. tS Patent Nos. 3,159,601 and 3 issued on December 1, 1964 to Mughby K.
, 159,662, platinum hydrocarbon complex B
Platinum acetylacetonate, shown in U.S. Pat. No. 3,723,497, issued March 27, 1973, to K. KLamoreau in issue 972
The platinum alcoholade catalysts described by x can be used.

For any of the specific platinum catalysts selected.

The practitioner can determine the optimum effective amount of catalyst to promote cure. The platinum catalyst is approximately 0.1 for the total formulation.
Sufficient amounts could be used effectively to provide ˜40 wt. of platinum. Example 1 of the above Wi111ng patent
A special platinum catalyst disclosed in
4 when used to give ~10 wt. of platinum atoms
It was found to be effective for 1.

To increase machining time, To1 practitioners may use certain known compounds to vary the hardening acceleration. For example, U.S. Patent No. 111E3,188, issued June 8, 1965.
, 299,
Pyridazine, f-silane, quinolipe2.2'-rquinoline, Cvp lysine, naphthyridine, quinaldine, dialkylformamide, Thioa-P, alkylthiourea and ethylenethiourea, US 1II, published June 8, 1965
1 Patent No. 5,188,300, Benzotriazole, as disclosed in U.S. Pat. Nitrile compounds disclosed in U.S. Patent No. 5,544,111, issued September 26, 1968; Halo car? No. 3,445, issued May 20, 1969,
Acetylenic compounds disclosed in No. 420, 19
No. 3,453,233, issued July 1, 1969.
sulfoxide compounds disclosed in U.S. Pat. No. 3,453,234, issued October 6, 1970, stannous salts disclosed in U.S. Pat. Dihydrous salt, t sumas (+3) salt.

Cuprous and cupric salts, the methyl-nylsiloxane cyclics mentioned in U.S. Pat. No. 5,925,705, issued Dec. 2, 1975, and other known can. The above cited patents.

Listed to provide additional details of methods of using platinum catalyst poisons, specific platinum catalyst poisons and platinum catalysts.

The polyorganosiloxanes unique to this invention can be prepared by cohydrolysis of the corresponding chlorosiloxanes to provide the required molar ratios of the components or by equilibration of the combined siloxane composition. The latter method using potassium silanolate as the equilibrium catalyst is preferred.

Representative I-liorganosiloxanes of the present invention can be prepared by equilibration according to the following examples: Example 1 Copolymer M@g7181 (081M8g) 60511ViMel
61-29゜M@8511 (OEiiMe,) s08
1Mel 236.29 and (M@11810)x
A mixture containing 937.4 g of lj-like substances (however, 4 to 6) was purged and heated to 160 °C for 1 hour, and potassium silica/9-L) (MO811 g) was heated to IK/2500 st as an equilibrium catalyst. were used and equilibrated. 1le8101,11 while maintaining temperature and stirring constantly.
(21,3 wt. 1 G), M@@@B10 (74.1 wt. L), and Me58100J (4.6 wt. 96) were added to Yuri and the resulting mixture was equilibrated for 6 hours. I let it happen. After neutralizing the reaction mixture with 0.00 ml of water, filter it. Polymer has a viscosity of 0.0002 m”
/B was shown.

Copoly w-B MslV181 (081M8g) 6081ViM@g
61.2 Ji', Mo2B5 (0#iMsl) 101
11Me324.7 Ii and (M61siO)
The reaction mixture was prepared by repeating the equilibration procedure using 170.8 g of the hydrolyzate used in the production of 1853.31i1 and colium. I passed away after neutralizing it. The resulting hot mer exhibited a viscosity of 0-002 m''/s.

Composition of Corimum M6B101.6 9.0 mole MegVi81
0. BO-75'E j' 4M113B106.21
7.25 mole Me1g10 83 mole M118101J2.0 mole- M@gVi8106J0.75 mole- M@6810), 5 0-95 mole Me181
0 96.50 Mol and B were then physically precipitated to produce polyorganosiloxanes of siloxane unit compositions having various viscosities. Polymer blends I and II are representative of 92 types of polymers obtained from such blends.
List.

Standard Ingredients Morchibori Maso L/7 Do I Me8101,5 5-62
ViM5-62Vi, 60.75 Me3B1004 4.03M1! Ig81
0 89-60 (viscosity 0.00
072m/g) Polymer Blend II M@8101J5.0ViM81g
106,6 0.75Me5810o,6
3-82 M114B10 90.43 (viscosity 0.00074 m) In order to blend a sample of polyorganosiloxane represented by Polymer Derend ■ and Blend ■ into a gel according to the present invention, first measure an appropriate amount of polymer 〇, and The platinum catalyst was added. The composition was stirred and the crosslinking compound was added to it. The mixture was then transferred to a small container and cured in a heated oil bath.

The reference polymer prene rI and polymer preyy■ have the formula HM@181(081Mel)-14081M@2H
A cross-linking agent and a platinum catalyst prepared by reacting sym-divinyltetramethyldisiloxane with chlorotetraplatinic acid as disclosed in Example 1 of the above Willing patent and cured. of siloxane compositions were produced. The special platinum catalyst complex used was 0.
．． Contained 85 wt.-platinum.

The penetration was measured in units of 0.1 square meters using a precision needle meter with a 4.51 Zorode attached to a 15 g Noranger. The penetration of Solode into gel sample 50I cured at 150° C. for 1 A hour was measured. The penetration level was read after 5 seconds. A high penetration value (above 10.0) represents a "soft" gel, while a low penetration value (less than 30) represents a "hard" gel.

The curing time of the gel was measured using a T.oamr gelmer with 7 spindles. Spin yl is 135℃
Nine samples were neutralized and immersed in an oil bath of 100I. Due to the formation (hardening) of gel, the resistance against the spindle increases, and the result is 6 ties on the gel! - to trip Kl! I recorded the time.

The low temperature properties of the gel were measured with a DuPont 900 Differential Thermal Analysis Calorimeter (DTA) K. 14 with liquid nitrogen
20 μg of gel sample cooled to 0°C was fractionated with DTA at 10°C.
heated at a rate of

Tables 1 and 2 show the composition and characteristics of a number of dels produced by the #IK of the present invention.

From the above, the gel produced according to the present invention has a temperature of about -120°C.
It was found that the glass phase transitions to a liquid phase at (Tg). No intermediate crystalline phase was observed.

Example 2 To illustrate the essential characteristics of polyorganosiloxanes for use in formulating siloxane gels according to the invention, the following gels were prepared and evaluated: Comparative Formulation ViMe F10-Terminated polydimethylsiloxane .

Divinyl content 0.22% by weight and viscosity 0.002 from ViMe181 (OMe281), 081MelVi
M@Bi, 01J9
Mole 1ViMeg8100J0.75 mol%, M
e38106J6-57 Molti and Me181085
．． Polymer B was blended with Polymer B having a vinyl content of 0.27 m''/g and a viscosity of 0.00019 m''/g. Polymer B#i was blended in a 1:1 weight ratio.

This polymer blend, 5oII, was mixed with an average formula % crosslinking agent of 0.37.9 and a platinum catalyst as disclosed in Example 1 of the Willing patent, supra (12 weight ppI of platinum on the final mixture). The butterfly was carried out in the same manner as disclosed in Example 10 of the above-mentioned US Pat. No. 3,020,260.

The resulting mixture was divided into the first part and the second part.

Part 1 was left at room temperature. It hardened to a gel in 45 minutes.

Part (2) was cured at 150° C. in 30 minutes.

The resulting gel had a penetrometer reading of 4.1 m. Phase transition temperature analysis using a differential scanning calorimeter needle showed a phase transition at -50°C and -120°C, representing the melting temperature and glass transition temperature, respectively. These two transition temperatures indicate that the gel can maintain low temperature structural integrity up to only 150°C. At temperatures below this point, a crystalline phase forms and the del becomes hard.

The formation of the crystalline phase appears to be due to the lack of Me8101J in the polymer. Maku, I Rimmer B is Me8101
, 3 units, the resulting polyorganosiloxane was a physical blend of methyl and vinylsiloxy units and not a siloxane polymer consisting of each essential unit.

The compositions of the present invention can be prepared by simply mixing together the various ingredients in any desired manner as described above, but sometimes these compositions can be prepared as two separate packages. It is most convenient to combine the two components when converting the cured composition to the cured state. For this two-component formulation, it is convenient to include the organopolysiloxane component and the platinum catalyst in the first package.

The second package may contain an organohydrogensiloxane and, conveniently, a portion of an organopolysiloxane. When selecting the contents of two packages, both the platinum catalyst component and the organohydrogensiloxane component should not be included in the same package.

The following examples demonstrate preferred embodiments of the invention.

Example 5 Curable composition Polymer Blend I [100 parts by weight Crosslinking agent (HMe2si(08,iMe2)-140
81M@aH) 5-14 1 Platinum catalyst
, 0946 #(MeViSiO)a
, o 2941. For convenience, it is desirable to package curable gel compositions in two-component form. The contents of each component are shown below.

A-component streamer blend■ 5og platinum catalyst
0.0911B Component Polymer Blend II 45.119 Crosslinking Agent 4.8 ? , 9(
Mevtsto), 0.028
11 For curing, components M and B were mixed in a 1:1 weight ratio, and the following properties were evaluated.92 Cure time (135°C
(at 100 g) 6.1 minutes 50 minutes (at 150°C) Cure end 4.5° Penetration of sample Cure time (at 25°C) 5 hours or more Cured gel within the scope of the invention prepared according to the examples 1, for example in space electronics, can be advantageously used as a conformal coating to protect electronic circuits where low temperature stability is important. The use of protective coatings that are low temperature stable is important because it has been observed that physical changes in the protective coating, e.g. from the R phase to the crystalline phase, can destroy and damage the coated circuitry. It is.

Claims (1)

[Claims] (1) (at essential K (OH3), 81080~
96.5 mol steamed rice, 0H38101, 32.0-10.0
Mole bun, C0Hs) 5810o, al, 25-6.0
Mol-and (OH15)2(0118絽OH)810
(A polyol characterized in that it consists of 40,25 to 4.0 moles is a nosiloxane; an organohydrogensiloxane having an organic group selected from the group consisting of an alkyl group of 1 to 6 carbon atoms, phenyl, and 3,3,3-trifluorozotetravir, the organohydrogensiloxane having a silicon bond. A curable siloxane composition consisting of a homogeneous mixture consisting essentially of: an organohydrogensiloxane that provides an average of 0.2 to 5.0 moles of silicon-bonded hydrogen per mole of vinyl; and (0) a platinum catalyst. Polyorganosiloxane is essentially (ORB
)281087~94%, 0R3B101.
33-6 Momoru Bun (OH15) s5+10o, a 2.
5-5 momoru bun (01113) 2 (011111-
wOH) 810o, consisting of 50.5 to 2.0 moles,
A curable siloxane composition according to claim 1. (3)-Liorganosiloxane is essentially (on,)2
sio 92-94 mol 4% 0H58101, 53-4
Mol%, (OHs) s810oJ2.5-5 momol cake (oH3), (aH*-on) sloo, so, 5-
Curable siloxane composition according to claim 2, comprising:
1 J5.0 mol-1 (oH3) 15sio, J3.8 mol-1 and (OHs) dew (OHzxOH) 81 (baO
The curable siloxane composition according to claim @2, comprising: (5) Organohydrogensiloxane is H(OH5)s81(O8i(OH3)s+)zosi
5. The curable siloxane composition according to any one of claims 1 to 4, wherein the siloxane composition has a molecular weight of 5 to 20. (6) Organohydrogen cloxane is H(oH,)lIIsi(ost(oHs)t), os
i(ous)sH (However, the number of stones is within the range of 5 to 20)
and the organohydrogen siloxane provides an average of 0.5 to 0.95 vol of silicon-bonded hydrogen per mole of silicon-bonded hydrogen. 1% curable siloxane composition according to any one of claims 1 to 4. 7. The curable siloxane composition of claim 1, wherein the platinum catalyst contributes from 5 to 104 platinum atoms to the total formulation. (8) The curable siloxane composition of claim 6, wherein the platinum catalyst provides from 5 to 10 weight-tons of platinum atoms based on the total formulation IIkJK.