RU2127746C1 - Gel-like organosilicon composition - Google Patents

Abstract

FIELD: chemical industry. SUBSTANCE: gel-like organosilicon comprises, wt. pts: polyorganovinyl siloxane having average number of vinyl groups of 3-12 in molecule which are attached with silicon atom, 100; polyorganohydrosiloxane, 0.5-10; polyorganovinyl siloxane having end trimethylsiloxy groups having average number of vinyl groups of 1-2 in molecule which are attached with silicon atom, 20-200; 7-100 ppm platinum catalyst (in terms of platinum). EFFECT: higher stability and improved characteristics of the composition in industrial production. 2 cl, 12 ex, 3 tbl

Description

 The invention relates to the field of compositions based on organosilicon liquid rubbers, cured by the polyaddition reaction, and more specifically to the field of low-modulus compositions - organosilicon gels.

 Organosilicon gels (KG) have recently found the widest application in various industries and science, in particular, to protect various electronic components and units from shock and vibration, as well as to create dynamic optical models of solid media.

 One of the first publications on the use of CG in electronics was made by C. Harper in the book "Filling of Electronic Equipment with Synthetic Resins" (1964).

 The most fully theoretically the properties of gels were studied by P. De Gennes in the book "Scaling Ideas in Polymer Physics" (1982).

 The world's leading manufacturers of silicone materials produce a fairly wide range of KG for various purposes. In particular, Tochiba produces KG under the brand name YE 5818 RTV, TSE 3051, Dow Corning Sylgard 527, X3-6779, Hipec 6110, Shin Etsu - KE 104LTV, etc.

 The closest technical solution chosen for the prototype is an organosilicon gel-like composition for protecting electronic components (application 63-35654, Japan, MKI C 08 L 83/05, RZh chemistry, ref. 2 T149).

Composition contains
A) polyorganohydride siloxane with a viscosity of 50 - 10000 (300 - 5000) cSt at 25 ^o C with an average number of H atoms in the molecule of Si bound to ≥ 1, with the remaining organic groups bound to the Si atom being (un) substituted monovalent hydrocarbon radicals not containing aliphatic unsaturated groups;
B) a polyorganosiloxane with an average number of vinyl groups in the molecule bonded to Si, ≥ 2, and the number of vinyl groups per hydrogen atom A bonded to Si is 0.1 - 3;
C) a catalyst based on Pt, Pd or Rh, and the content of catalytic metals with respect to the amount of A and B is 0.01 - 50 • 10 ^-6 .

 The composition is used to create protective coatings on top of the structure of hybrid and large integrated circuits.

 However, the change in the modulus of elasticity of KG on the concentration of a crosslinking agent, polyorganohydride siloxane in the composition adopted as a prototype, has a rather sharp dependence, i.e. a small change in the concentration of the crosslinking agent leads to a significant change in the modulus of elasticity. This, as well as the technological variation in the parameters of the composition components that always take place, leads to the fact that the modulus of elasticity of the CG varies from batch to batch. In a number of industries, for example, in dynamic optical models, etc., this is unacceptable.

 The technical task of the invention is to increase the stability of the compositions and their characteristics in industrial production.

The technical result is achieved by the fact that the proposed organosilicon gel-like composition includes polyorganovinyl siloxane with trimethylsiloxy-terminal groups with an average number of vinyl groups in the molecule associated with Si, 3-12 (POS-1), polyorganohydride siloxane (OGS) and a platinum catalyst and differs from the known one by the additional presence of polyorganosiloxane with terminal trimethylsiloxy groups with an average number of vinyl groups in the molecule associated with Si, 1-2 (POS-2) in the following ratio of components (parts by weight):
Polyorganovinylsiloxane (POS-1) - 100
Polyorganohydridosiloxane (OGS) - 0.5 - 10
Polyorganovinylsiloxane (POS-2) - 20 - 200
Platinum catalyst (in terms of platinum) - 7 - 100 ppm.

In addition, the composition may contain oligoorganosiloxane with terminal trimethylsiloxy groups in an amount of 5 to 150 parts by weight per 100 parts by weight POS-1
The chemical composition of polyorganosiloxanes can be represented by the general formula
POS-1 M 'M _150-670 M'' _3-12 M',
POS-2 M 'M _150-670 M'' _1-2 M',
where M '- (CH ₃ ) ₃ SiO-
M - - (CH ₃ ) ₂ SiO-; (C ₆ H ₅ ) (CH ₃ ) SiO-; (CF ₃ CH ₂ CH ₂ ) (CH ₃ ) SiO-
M '' - - (CH ₃ ) (CH ₂ -CH) SiO-
The viscosities of POS-1 and POS-2 are 200 - 6500 cSt, the content of unsaturated groups characterized by the bromine number (Bp) is 3.5 - 4.5 and 0.5 - 1.5, respectively.

Receive them by known methods: anionic or cationic copolymerization of cyclic and / or linear organosiloxanes. The viscosity is controlled by the dosage of hexorganorganosiloxanes or organosiloxanes with terminal triorganosiloxy groups. As a copolymerization catalyst, aqueous solutions of KOH, CsOH, (CH ₃ ) ₄ NOH and their siloxanolates, cation exchange resins, acidic clays are used. Obtaining PIC-1 and PIC-2 is illustrated by the following examples.

Example 1. In a three-necked flask equipped with a stirrer, thermometer and reflux condenser, 100 g of depolymerizate (D ₄ , dimethylcyclosiloxane), 15.98 methylphenylcyclosiloxane (A ₃ ), 2.53 g of methyl vinylcyclosiloxane (B ₄ ), 1.60 g of hexamethyldisiloxane are charged (HMDS), heated with stirring to 60 ^o C, add 2 g of cation exchanger KU-23 and stir at this temperature for 4 hours. Then the cation exchange resin is filtered off and the unreacted monomers are distilled off from the formed polymer at a temperature of 150-170 ^° C and a residual pressure of 5-25 mmHg. Art.

 The characteristics obtained in examples 1 to 8 samples are given in table. 1.

Example 2. The process is carried out analogously to example 1, only for copolymerization take 100 g of D ₄ , 1.94 g of hydrolyzate of methyl vinyl dichlorosilane (MVDHS), 1.4 g of oligodimethylsiloxane liquid PMS-1,5.

The hydrolysis of MVDHS is carried out as follows. 300 ml of water are charged into a four-necked flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer, and 141 g (1 mol) of MVDHS are added dropwise from the dropping funnel for 2 hours while maintaining the hydrolysis temperature of 15 - 20 ^° C. Then the reaction mixture is further mixed. 2 hours. The hydrolyzate is separated, washed until neutral, dried over calcium chloride and sodium bicarbonate and used in the copolymerization as a vinyl-containing component in examples 2 and 3.

 Example 3. The process is carried out analogously to example 2, only for copolymerization take 100 g of dimethylsiloxane liquid PMS-100, 2.6 g of hydrolyzate MVDHS and 1.5 g PMS-1.5.

Example 4. In a three-necked flask, 100 g of D ₄ , 2.4 g of B ₄ , 21.4 g of methyl-γ-trifluoropropylcyclosiloxane (F ₃ ), 0.75 g of PMS-5 are charged, heated to 140 ^° C. with stirring, and introduced in the reaction mixture of 0.009 ml of a 40% aqueous solution of CsOH, after 1 hour, 0.018 ml of silyl phosphate containing 10% H ₃ PO _{4 was} added. Unreacted monomers are distilled off at 140 - 160 ^o C and a residual pressure of 10 - 30 mm RT. Art.

Example 5. Analogously to example 4, only 100 g of PMS-200, 21 g of F ₃ , 0.65 g of B ₄ and 1.4 g of PMS-1.5 are taken and the copolymerization takes 6 hours.

 Example 6. Analogously to example 1, only the vinyl-containing component is the co-hydrolyzate of dimethyldichlorosilane (DMDHS), methyl vinyl dichlorosilane (MVDHS) and trimethylchlorosilane (TMHS) in a molar ratio of 9: 3: 2.

Cohydrolysis is as follows. 320 ml of water are poured into a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel. From a dropping funnel, a mixture of 116 g of DMDHS, 42.3 g of MVDHS and 21.7 g of TMDHS is added dropwise to water for 2 hours. The cohydrolysis temperature is not higher than 30 ^o C. Upon completion of the supply of chlorosilanes, the reaction mixture is stirred for another 2 hours. Then cohydrolyzate is separated, washed with sodium bicarbonate solution until neutral, dried over calcium chloride. The resulting cohydrolyzate has a bromine number of 44.2.

For copolymerization, 100 g of D ₄ , 15.9 g of A ₃ , 3.34 g of cohydrolyzate with a bromine number of 44.2 and 1.7 g of HMDS are taken.

Example 7. In a three-necked flask equipped with a stirrer, thermometer and reflux condenser, 100 g of depolymerizate D ₄ , 1.5 g of cohydrolyzate with a bromine number of 44.2 (see Example 6) and 0.6 g of PMS-1.5 are charged. The contents are heated with stirring to 140 ^° C., 0.005 g of KOH in the form of potassium siloxanolate is added and the process is carried out for 1 hour, then the temperature is reduced to 120 ^° C., 0.005 g of H ₃ PO _{4 is} added, and the mixture is stirred for 0.5 hour. Then the monomers are distilled off at a temperature of 140 - 170 ^o C and a residual pressure of 5 - 25 mm RT. Art.

 Example 8. Analogously to example 1, only take 100 g PMS-1000, 3.0 g cohydrolyzate with a bromine number of 44.2 (see example 6) DMDHS, MVDHS, TMHS. The properties of the obtained oligomers - viscosity and bromine number are shown in table 1.

где M' - (CH₃)₃SiO-;
M^* - CH₃HSi-;
M''' - (CH₃)₂SiO-;
M'''' - C₆H₅(CH₃SiO-; CF₃CH₂CH₂(CH₃)SiO-; C₂H₅(CH₃)SiO-.As a crosslinking component, polyorganohydridesiloxane with a hydrogen content of H _Si = 0.42-1.8%, with a viscosity of 10-130 cSt / 20 ^o C of the general formula is used
M '

where M 'is (CH ₃ ) ₃ SiO-;
M ^* is CH ₃ HSi-;
M '''- (CH ₃ ) ₂ SiO-;
M '''' - C ₆ H ₅ (CH ₃ SiO-; CF ₃ CH ₂ CH ₂ (CH ₃ ) SiO-; C ₂ H ₅ (CH ₃ ) SiO-.

 The preparation of polyorganohydride siloxanes (OHS) is carried out by known methods — by cohydrolysis of the corresponding organochlorosilanes and is illustrated by the following examples.

Example 9. In a four-necked flask (hydrolyzer) equipped with a stirrer, a reflux condenser with a gas outlet tube and a thermometer, 400 ml of water was charged. A mixture of 21.7 g of trimethylchlorosilane (TMXC), 61.9 g of methyldichlorosilane (MDXC), 103.2 g of DMDC is added dropwise with stirring from a dropping funnel for 2 hours. The hydrolysis temperature is <20 ^o C. After completion of digging, the mixture is stirred for 2 hours, allowed to stand for 2 hours, the cohydrolyzate is separated, washed with a soda solution until neutral, and dried with calcium chloride. The characteristics of the obtained dimethylmethylhydride siloxane are shown in table 2.

Example 10. The process is carried out analogously to example 9, only for co-hydrolysis take 5.4 g of TMHS, 86.3 g of MDHS, 90.3 g of DMHS, 29.9 g of MFHS. Neutral hydrolyzate 105 g is loaded into a three-headed flask equipped with a stirrer and a thermometer, heated to 75 ^° C, 2 g of KU-23 resin are added and a catalytic rearrangement is carried out for 1 hour, then the KU-23 resin is filtered off, the volatiles are distilled off at 120 ^° C and residual pressure of 20 mm RT. Art.

 Example 11. The process is carried out analogously to example 10, only for co-hydrolysis take 5.4 g of TMHS, 57.5 g of MDHS, 109.7 g of DMHS, 31.7 methyl-γ-trifluoropropyl dichlorosilane (M-γ-TFPDHS).

 Example 12. The process is carried out analogously to example 10, only for co-hydrolysis take 2.17 g TMHS, 63.25 g MDHS, 77.4 g DMDC.

 Example 13. As a crosslinking agent, an industrially produced product GKZH-94 (GOST 10834-76) is used.

 Example 14. As a crosslinking agent, an industrially produced product GKZH-94M (TU6-02694-72) is used.

 The properties of the oligoorganohydride siloxanes obtained are shown in Table 2.

 The composition may additionally contain oligoorganosiloxanes (OOS), which can be used as oligoorganosiloxanes grades PMS-200, PMS-1000, 133-79, 161-44.

To prepare the composition, the components are mixed in the indicated proportions (table 3), after which the samples are cured at a temperature of 150 ^o C for 5 hours.

,
где E₁, E₂, ν₁, ν₂ - модули Юнга и коэффициенты Пуассона индентора и исследуемого материала соответственно;
F - сила, действующая на сферический индентор радиуса R.The elastic modulus of the cured composition was determined by a method based on the method for determining the hardness of plastics, in which the elastic modulus is determined by the load and depth of penetration of a spherical indenter. According to this theory, the penetration depth h of a spherical indenter into the flat surface of the sample is

,
where E ₁ , E ₂ , ν ₁ , ν ₂ are Young's moduli and Poisson's ratios of the indenter and the material under study, respectively;
F is the force acting on a spherical indenter of radius R.

.If E ₁ > E ₂ , then the elastic modulus of the studied material can be calculated by the depth of penetration of the indenter:

.

 Examples 6 used oligomethylphenylsiloxane grades 133-79, 8 oligomethyl-γ-trifluoropropylsiloxane grades 161-44, 7 and 10 oligomethylsiloxanes grades PMS-200 and PMS-1000, respectively.

In the composition, catalysts are used, which are platinum complex compounds in which organosilicon compounds of the general formula serve as ligands
[(CH ₃ ) _n (CH ₂ = CH) _3-n Si] ₂ O,
where n = 0 - 2,
(US 3775452 A, 1973), as well as platinum on various carriers, etc.

 Examples 11 and 12 are made according to the prototype. It can be seen that with an increase in the concentration of the crosslinking agent by a factor of 2, the elastic modulus increases by more than four times, while with the same change in the concentration of the crosslinking agent in Examples 1 and 9 performed according to the proposed formula, the elastic modulus grows by less than 1, 5 times.

 Thus, the proposed composition provides a smoother change in the modulus of elasticity of the composition with a change in the concentration of a crosslinking agent.

Claims (1)

1. Organosilicon gel-like composition comprising polyorganovinylsiloxane with trimethylsiloxy-terminal groups, with an average amount of vinyl groups bound to the silicon atom in the molecule of 3-12 (POS-1), organopolysiloxane (OHS) and a platinum catalyst, characterized in that it additionally contains a polyorganosiloxane with terminal trimethylsiloxy groups with an average amount in the molecule of vinyl groups bonded to a silicon atom equal to 1 - 2 (POS-2), in the following ratio of components, parts by weight:
Polyorganovinylsiloxane (POS-1) - 100
Polyorganohydridosiloxane (OGS) - 0.5 - 10
Polyorganovinylsiloxane (POS-2) - 20 - 200
Platinum catalyst (in terms of platinum) - 7 - 100 ppm
2. Organosilicon gel-like composition according to claim 1. characterized in that it additionally contains oligoorganosiloxane with terminal trimethylsiloxy groups in an amount of 5 to 150 parts by weight per 100 parts by weight polyorganovinylsiloxane (POS-1).

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