WO1997044381A1

WO1997044381A1 - Foamable organosiloxane composition

Info

Publication number: WO1997044381A1
Application number: PCT/RU1996/000194
Authority: WO
Inventors: Vadim Vladimirovich Severnyi; Anatolii Petrovich Kuleshov; Nadezhda Alekseevna Karugina; Spartak Timofeevich Belyaev; Alexandr Nikolaevich Polivanov; Natalia Mikhailovna Kozodaeva; Marina Mikhailovna Kozodaeva; Sergei Alexandrovich Perevozchikov; Ivan Konstantinovich Shvetsov; Piter Gulko
Original assignee: Obschestvennoe Obiedinenie 'euro-Asian Physical Society'
Priority date: 1996-05-20
Filing date: 1996-07-16
Publication date: 1997-11-27
Also published as: DE19711519A1; RU2115676C1; JPH11509886A

Abstract

The present invention relates to methods for producing foamable organosiloxane compositions having improved fire-resistance ratings and radiation resistance. This foamable organosiloxane composition comprises a liquid organosiloxane rubber (OR), an organosilicon cross-linking agent (CA) and a carbonate filler (CF). This composition uses as OR a rubber or mixture of rubbers corresponding to general formula (I) where R, R?1 and R2¿ each represent a lower alkyl radical with 1 to 6 carbon atoms or an aryl radical with 6 to 10 carbon atoms; n is an integer between 10 and 1500 while k and l are integers between 0 and 500. This composition uses as CA a compound of the general formula R3SiX3 where R3 is an alkyl radical with 1 to 6 carbon atoms, an aryl radical with 6 to 10 carbon atoms, an arylalkyl radical with 7 to 12 carbon atoms or an alkenyl radical with 2 to 4 carbon atoms. X represents halogen or a compound of the general formula OC(O)R4 where R4 is an alkyl radical with 1 to 6 carbon atoms or an aryl radical with 6 to 12 carbon atoms. This composition finally uses as CF one or more substances chosen from the compounds corresponding to the general formula M¿x?CO3 where M is NaH, NH4, Na, K, Ca, Mg or Ba, and x is 1 or 2. Those components are selected according to the following amounts in parts per weight: 100 of OR; from 5 to 30 of CA; and from 20 to 120 of CF.

Description

FOAMABLE ORGANOSILOXANE COMPOSITION

The present invention relates to methods for producing expandable organosiloxane compositions with improved fire and radiation resistance, which can be used for the isolation of various objects.

BACKGROUND OF THE INVENTION Foaming organosiloxane compositions are known that are prepared by mixing organosilanes of the oceans, crosslinking agents and foaming agents.

The foam structure of such materials is formed as a result of the reaction of organohydride siloxanes containing at least 2 ≡ 5-Η groups in a molecule with water or compounds containing ≡ 8≡Η groups (from, A, 5238967) or = С-ОН (from, A, 5356940). These reactions proceed under the catalytic effect of platinum compounds Cis, A, 5216037) or bases (from, A, 4987155).

Giving fire resistance to such compositions can be carried out by several methods, the main of which are the introduction of platinum in the composition of compounds in quantities significantly exceeding catalytic (from, A. 5216037). Another method is the introduction of traditional antipyrenes into the composition (from, A. 4695597). The resulting foam elastomers are practically non-combustible. However, the use of known non-combustible foam elastomers is difficult, in particular, due to the high cost of platinum compounds introduced into the composition. In addition, the foaming of organosiloxane compositions is carried out by hydrogen, which is released as a result of reactions when the components are mixed. As you know, hydrogen is able to form explosive mixtures with a wide range of concentrations with oxygen contained in air.

Thus, the preparation of known expandable organosiloxane compositions requires special precautions. The presence of hydrogen as an indispensable factor in the formation of the structure of known foam elastomers does not allow, in addition, to use them in the isolation of any objects where contact is possible foaming elastomer with heated surfaces, sparks, open flames. ννθ 97/44381 ₂ ΡСΤ / ΙШ96 / 00194

Closest to the present invention is an expandable organosiloxane composition comprising liquid organosiloxane rubber, an organosilicon crosslinking agent, and a carbonate filler (LZ, A, 4705810). In the known composition, the formation of the porous structure is carried out by carbon dioxide (CO2), which is formed by the reaction of calcium carbonate and carboxylic acids. However, in the known composition there are compounds with groups ≡ 5.Η, capable of reacting with carboxylic acids with the release of hydrogen. In addition, foaming of the known composition is carried out at temperatures of 150-180 ° C, which also contributes to the evolution of hydrogen.

Thus, upon receipt of this known expandable organosiloxane composition, the risk of the formation of an explosive mixture is reduced to a certain extent.

However, hydrogen evolution and high foaming temperatures make it difficult to use this composition. In addition, the known composition does not have satisfactory fire resistance and radiation resistance.

The latter circumstance prevents the use of the known expandable organosiloxane composition in the manufacture of insulating coatings or encapsulation of objects contaminated with radionuclides (storage facilities or repositories of radioactive waste, including those containing fissile isotopes ΤЛ-235 and Ρи-239, rooms and sites contaminated as a result of accidents at nuclear facilities).

Insulating materials used for such purposes, in addition to incombustibility, should emit the smallest possible amount of fire and explosive gases when exposed to large doses of radiation, while maintaining their original shape and size. In some cases, such materials must be capable of absorbing neutrons produced during the decay of fissile isotopes. Disclosure of Invention

The problem to which the present invention is directed is the creation of a foamable organosiloxane composition with improved fire and radiation resistance, which would be applicable as an insulating non-combustible material, as well as eliminating the possibility the formation of an explosive gas mixture at the stage of formation of the foam structure.

The technical result achieved by the present invention is to ensure the incombustibility of the materials obtained from the composition, to reduce gas emission, to preserve the structure and shape when exposed to radiation, as well as the absence of hydrogen evolution from the composition at the stage of formation of the foam structure.

An additional technical result is an increase in the absorption capacity for neutrons in materials obtained from expandable organosiloxane compositions.

The above technical results are achieved in that an expandable organosiloxane composition comprising a liquid organosiloxane rubber, an organosilicon crosslinking agent and a carbonate filler according to the invention contains rubber or a mixture of rubbers of the general formula as organosiloxane rubber:

where K, K. ¹ , Κ ^? is a lower alkyl radical with 1 to 6 carbon atoms or an aryl radical with 6 to 10 carbon atoms, n is an integer from 10 to 1500, k, 1 is an integer from 0 to 500. the sum (η + k + 1) is an integer a number from 10 to 1500, t is an integer from 0 to 10, as an organosilicon crosslinking agent, contains a compound of the general formula: K ¹ ZX.ι or mixtures thereof, where

K. ³ is an alkyl radical with 1 to 6 carbon atoms, an aryl radical with 6 to 10 carbon atoms, an arylalkyl radical with 7 to 12 carbon atoms or alk ΡС Κ 194 is a nyl radical with 2 to 4 carbon atoms, X is a halogen or a compound of the general formula ΟС (0) Κ ⁴ , where K ⁴ is an alkyl radical with 1 to 6 carbon atoms or an aryl radical with 6 to 12 carbon atoms, as the carbonate filler contains at least one substance from compounds with the general formula MxCOi, where M is NaH, ₄ , Na, K, Ca, Mβ, Ba, x - 1 or 2, with the following ratio of components (in May. parts ): organosiloxane rubber - 100 organosilicon crosslinking agent - 5 - 30 carbonate filler - 20 - 120.

Embodiments are possible in which it is advisable that:

- the composition would additionally contain from 60 to 150 parts of aluminum hydroxide,

- the composition would additionally contain from 0.01 to 0.5 parts of tin dialkyl dicarboxylate of the general formula:

Κ. ⁵ _? Зη [ΟС (0) Κ. ⁶ ] ₂ , where

K ⁵ is an alkyl radical with 2 to 4 carbon atoms, K ⁶ is an alkyl radical with 8 to 12 carbon atoms,

- the composition would additionally contain from 0.01 to 0.3 parts of dispersed boron with a specific surface area of 3 to 10 m ² / g and particle sizes in the range of 0.2 to 20 μm,

- in the composition, aluminum hydroxide would be used in the form of a powder with particle sizes in the range from 0.5 to 10 microns,

- would boron be introduced into the composition as a part of at least one compound from the group: B? Oz, NZOz, ΤϊΒ ₂ , ZϊzVd, Α1Β.

The expandable organosiloxane composition is prepared as follows.

The liquid organosiloxane rubber and the carbonate filler are mixed, after which a crosslinking agent is added to the mixture. Aluminum hydroxide and dispersed boron are introduced into the mixture, depending on the need to increase the corresponding properties of the resulting material. Moreover, these additives are introduced into the mixture before the introduction of a crosslinking agent.

Liquid organosiloxane rubbers used in the present invention belong to the class of linear and linear ladder polyorganosiloxanes. described, in particular, in the work (High-molecular compounds, volume XXX, Ν 9, Moscow, 1988, p. 1832 - 1836). When a crosslinking agent is introduced into a pre-prepared mixture of liquid organosiloxane rubber and a carbonate filler, a reaction of the components occurs, which leads to the crosslinking of the rubber and the simultaneous release of acidic HX products (hydrogen chloride or carboxylic acids) according to the scheme ≡ 5ΗΗ + -> ≡ ЗЗЗϊ + ΗΧ. HX products at the moment of isolation are neutralized due to the reaction with a bicarbonate filler, which is in excess, forming carbon dioxide CO; and corresponding salts. The evolution of hydrogen or other combustible or explosive gases during the above reactions is fundamentally impossible. Since all of the above reactions proceed simultaneously, the absorbing carbon dioxide foams the total composition, and the resulting foam is fixed by crosslinking the rubber to form a foam elastomer.

In order to make the foam elastomer incombustible, flame retardants in the form of aluminum hydroxide powder with particle sizes from 0.5 to 10 microns can be added to the mixture of liquid rubbers, carbonate filler and crosslinking agents.

In addition, flame retardants can form as by-products (salts). formed during the reaction of a carbonate filler with HX compounds.

The foamed polyorganosiloxane compositions obtained in accordance with the present invention, in addition to high heat resistance, have very little gas evolution when exposed to radioactive radiation of up to 500 Mrad. The resulting solid residue is a mixed silicate-carbonate of the metals that make up the composition, while it retains the original size and shape of the foam elastomer before irradiation and in appearance resembles a strong volcanic pumice.

If the proposed expandable composition is used to isolate or encapsulate radioactive substances containing fissile radionuclides (υ-235, Рιι-239, etc.), additives that provide neutron absorption and reduce the coefficient can be introduced into the composition _β ΡСΤ / κυ96 / 00194 of neutron multiplication up to Κ∞ <0.95, ensuring nuclear safety.

As such additives, a boron-containing substance in the form of a dispersed powder is used. The expandable organosiloxane compositions of the present invention have a high degree of fire resistance. Samples of this material placed in the Bunsen burner flame do not ignite, but undergo slow mineralization from the surface, which ceases after removal of the samples from the flame. According to another embodiment of the fire tests, the samples of the foam elastomers obtained according to the present invention were impregnated with combustible solvents (gasoline and kerosene), placed in porcelain cups and set on fire. As these solvents burned out, soot deposits formed on the surface of the samples, and the flame went out after the completion of the burning of the solvents.

The above properties of the expandable organosiloxane compositions obtained in accordance with the present invention allow us to consider them as promising materials for the manufacture of fire-resistant protective clothing, fire-retardant coatings, fire-retardant lightweight partitions in buildings, ships, rooms, fireproof sealing of openings after laying cables and wires in them etc.

An important feature of such materials is the practical absence of smoke formation during the transformation of foam elastomers under the action of an open flame into a durable foam ceramic. Features and advantages of the present invention will become more clear upon subsequent consideration of examples of implementation of the invention, as well as the results of fire and radiation tests.

Preparation of compositions. For 100 mass parts of liquid polyorganosiloxane rubbers, with the above general formula, which can be used either as individual compounds or as a mixture of rubbers with various values of K, K ¹ , K ² , p, t, 1, k given above, from 20 to 120 parts of a carbonate filler, in which at least one substance is used from compounds with the general formula (Μ) χСΟз, where M is ΝaH, ΝΗ ₄ , Νa, K, Ca, Μ§ or Ba, and x is \ YΟ 97 1 y Ρ Κ

1 or 2. In this case, the fillers are introduced in the form of dispersed powders with particle sizes from 1 to 10 microns.

Additives in the form of dispersed powders of aluminum hydroxide and / or boron-containing substances can be added to the mixture. The resulting mixture is thoroughly mixed on roller mixers to obtain a homogeneous plastic paste with a viscosity of 30,000 to 120,000 Pa s.

To obtain a foamed organosiloxane composition (hereinafter, the foam elastomer), they are taken as of May 100. parts of rubber from 5 to 30 parts by mass of crosslinking agents, which are used either as individual compounds or as a mixture of compounds with the general formula Κ. ³ 8ϊΧz with the above values of K. ³ , X.

From 0.01 to 0.5 parts of tin dialkyl dicarboxylates (for example, tin diethyl dicaprylate or tin dibutyl dilaurate) can also be added to the composition to control the foaming rate. After 15 to 20 seconds after mixing the paste and cross-linking agents, foaming of the mass begins, accompanied by a slight self-heating up to 35 - 45 ° С, as a result of which its volume will increase by 1.5 - 10 times.

The resulting viscous plastic foam gradually over a period of 2 to 10 minutes. loses fluidity and surface stickiness. The complete completion of vulcanization takes place in 20 - 90 minutes. (after the specified time, the density and elasticity of the foam remain constant). Similarly, the formation of foam elastomer proceeds on any dry, wet surfaces, as well as on the surface of water and aqueous solutions.

Examples of the preparation of specific compositions in accordance with the present invention are given below under the numbers 2 to 6. Example 1 describes the preparation of a composition in accordance with the closest analogue (from, 4705810).

In examples 2 to 6, the values of the components are given in mass parts. Rubber viscosity η is given in MPa-s.

Examples of the invention Example Ν 1.

In accordance with the invention, the closest analogue is preparing a composition consisting of components A, B and C.

To prepare component (A), 100 mass parts of dimethylpolysiloxane with a viscosity of 90,000 mPa-s blocked at the ends of dimethylvinyl \ УΟ 97/44381 ₈ ΡСΤ / ΙШ96 / 00194 siloxanes (I); mixed since May 70th. parts of ground quartz with particle sizes up to 5 μm (II) and a solution of Н ^ РϊСΙ _б- бНгО in isopropyl alcohol is added to the mixture in an amount providing 10 ⁴ parts of Рϊ for 1 part of the mixture. The mixture is stirred in a mechanical mortar until a homogeneous paste is obtained. Prepare a component of composition (B) by mixing on May 90. part (I) from May 10. h. of the product of cohydrolysis in toluene 1 mole (Cr2O3 ^ 3 and 2 moles (CH3CH3C3, from which, after washing with water, all volatile products are distilled off to a temperature of 130 ° C. May 60 is added to the resulting mixture and the mixture is stirred in mechanical step until a homogeneous paste is obtained.Prepare the component of composition (C) by mixing on May 100, including calcium carbonate with particle sizes up to 0.5 μm, from May 80, including pouring revenge on the ocean, blocked at the ends of (СΗз) ЗЗЮο, 5 - in groups, with a viscosity of 100 mPas ,.

Grind the mixture in a mechanical mortar to a homogeneous paste, after which they are added to it on May 60. including adipic acid. Mix components (A) and (B) in a ratio of 1: 1 and mix them thoroughly. To 100 parts by weight the resulting mixture was added on May 6th. including component (C) and again fray in a mechanical mortar. The resulting paste is placed in a mold and kept in a heating cabinet at a temperature of 175 ° C for 15 minutes. After foaming and cooling, a uniform elastic foam with a density of 0.6 g / cm ^{3 is} obtained.

Example Ν 2.

In accordance with the present invention, a composition is prepared by mixing:

Organosiloxane rubber: - 100

(n = 700, k = 1 = 0, n + k + 1 = 700, t = 0, K. - CH3, K ¹ - C ₆ Η ₅ , η = 8000) Crosslinking agent: - 20

Carbonate Filler: - 50

Νa? SΟz

Aluminum hydroxide: - 150 Α1 (ΟΗ) s

Dispersion Boron: - 0.2

IN

Tin dialkyl dicarboxylate: - 0.01

(С _? Ι 1 ₅ ).? Зη [ΟС (0) С7Ηι ₅ |: 97/443 1 _d ΡСΤ / ΙШ96 / 00194

Prepared in accordance with the above sequence of steps, the mixture in the form of a liquid paste is poured into a mold of PTFE or polyethylene. Within 2 - 5 minutes, foaming and curing of the mixture occurs with the formation of a uniform elastic foam elastomer, which is easily removed from the mold after 20 - 90 minutes. The density of the obtained elastomer is 0.24 g / cm ³ .

Foaming compositions of Examples 3-6 are similarly prepared.

Example Ν 3. Yu Prepare the composition by mixing:

Organosiloxane rubber: - 100

(η = 10, k = 1 = 0, n + k + 1 = 10. m = 10, K. - CH3, K. ¹ - CH3, K ² -C ₆ Η ₅ , η = 7200)

Crosslinking Agent: - 20

1 * ι (mixture), including

Cr5. (C3CC3) s - 5

C ₆ Η ₅ 3-C - 15

Carbonate Filler: - 50

(mixture), including 0 Κ ₂ СΟз - 30 меСОз - 20

I aluminum oxide: - 100

ΑΙ (ΟΗ) ι

Dispersed boron: - 0.8 5 Β? Οз

Tin dihydroxycarboxylate: - 0.01

(С _? Η ₅ ) 23 ^η ΙΟС (0) С ₇ Ηϊ5] ₂

After foaming the composition, a homogeneous foam with a density of 0, 43 g / cm ^{3 is} obtained.

Example Ν 4.

Prepare the composition by mixing:

A mixture of organosiloxane rubbers η = 4400, including 100 \ νθ 97/44381 _{1 0} ΡСΤ / Κϋ96 / 00194

Κ.-СΗз, К'-СНз. Kr-CEPB) - 40 b) (η = 300, k = 1 = 50, n + k + 1 = 400, t = 0, Κ.-СΗ ₃ , Κ'-СΗ ₃ , Κ ² -С ₆ Η ₅ ) - 40 c) (η = 100. K = 1 = 50, n + k + 1 = 200, m = 0, Κ-C ₂ Η ₅ , K'-CH3, Κ ² -C ₆ Η ^) - 20

Crosslinking agent: - 20 СΗз8ϊ (СΗзСΟΟ) з

Carbonate Filler: - 90

(mixture), including

CaCO3 - 60

VasOz - 10 Κ ₂ СΟз - 20

Aluminum hydroxide: - 60

Α1 (ΟΗ) s

Dispersion Boron: - 1.2

PZvoz tin dialkyl dicarboxylate: - 0.5

(С ₄ Η9) ₂ З ^η [ΟС (0) С ₁₁ Η ₂ зЬ

After foaming the composition, a homogeneous yen with a density of 62 g / cm ^{3 is} obtained.

Example Ν 5. Prepare the composition by mixing:

Organosiloxane rubber: - 100

(η = 300,

0, Κ - СНз, К ¹ - СНз, η = 1800)

Crosslinking Agent: - 16

(mixture), including СΗ ₃ 8ϊ (СΗзСΟΟ) з - 8

С ₂ Η ₅ Зϊ (СΗзСΟΟ) з - 8

Carbonate Filler: - 120

(ΝΗ ₄ ) ₂ СΟз

Tin dialkyl dicarboxylate: - 0.3 (С ₂ Η ₅ ) ₂ Зη [ΟС (0) С7Ηϊ5] ₂

After foaming the composition, a uniform foam with a density of 32 g / cm ^{3 is} obtained.

Example Ν 6.

1 will take the composition by mixing: \ νθ 97/44381 _{1 1} ΡСΤ / ΙШ96 / 00194

A mixture of organosiloxane rubbers η = 40,000, including 100 a)

Ε.-СΗ ₃ , К '-СНз, Κ ^2- СбΗ ₅₎ ) - 50

1200, t = 0, K-CH3, K'-CH3,) - 50

Crosslinking agent: - 30 (mixture), including

(СΗ ₂ = СΗ) ЗϊС1з - 5

SNZZϊSΙz - 25

Carbonate Filler: - 60

(mixture), including Νа ₂ СΟз - 30

НСаНСОз - 30

Aluminum hydroxide: - 80

Αϊ (ΟΗ) ₃ Dispersion bur: - 0.8 Τ.Β ₂

After foaming the composition, a uniform foam with a density of 0.51 g / cm ^{3 is} obtained.

The results of radiation and fire tests of samples of foam elastomers obtained in accordance with the present invention and according to the invention, the closest analogue, are shown in table 1 and table 2.

The tests were carried out with samples of materials measuring 50x30x20 mm.

\ νθ 97/44381 ΡСΤ / ΙШ96 / П0194

12

Table 1. Results of radiation tests

(dose rate 2 Mrad / hour, integral dose 500 Mrad)

- at a dose of up to 100 Mrad

Table 2. Fire test results.

* - after complete combustion of fuel

As follows from the test results, the expandable organosiloxane compositions obtained in accordance with the present invention have an order of magnitude better radiation resistance than the known compositions, form a solid solid residue after irradiation, and are practically not subject to fire. When foam is formed, hydrogen evolution is absent.

In addition, as tests have shown, when foaming the catalyzed composition on dry metals, glass, concrete, many types of plastics, organic and silicone rubbers, the adhesive strength of the foam elastomers. obtained in accordance with the present invention exceeds its cohesive \ νθ 97/44381 ₁ ^ ΡСΤ / ΙШ96 / 00194 strength. When the composition is applied to water or aqueous solutions, a continuous porous film forms on the surface. INDUSTRIAL APPLICABILITY The present invention can be best used in the manufacture of materials used, in particular, in the aviation industry as flame-retardant, non-toxic gap fillers, trench sealants, electrical wiring, floors, fire-resistant wall coatings without the use of combustible adhesives, as well as thermo and soundproof materials. The materials prepared in accordance with the present invention can also be used to isolate objects contaminated with radionuclides from the external environment.

Claims

\ UΟ 97/44381 15 ΡCΤ / κυ96 / 00194Formula of the INVENTION

1. Foaming organosiloxane composition containing liquid organosiloxane rubber, an organosilicon crosslinking agent and a carbonate filler, characterized in that as organosiloxane rubber contains rubber or a mixture of rubbers of the General formula:

15 where K, K ¹ , K ² is a lower alkyl radical with 1 to 6 carbon atoms or an aryl radical with 6 to 10 carbon atoms, n is an integer from 10 to 1500, k, 1 are integers from 0 to 500, the sum (η + k + 1) - is an integer from 10 to 1500 m - an integer from 0 to 10, as kremniyorganncheskogo crosslinker comprises a compound of the general formula 20: 1h ZϊH ³ h or mixtures thereof, wherein

K ^h - alkyl radical c! - 6 carbon atoms, an aryl radical with 6 to 10 carbon atoms, an aryloalkyl radical 7 to 12 carbon atoms or an alkylene radical with 2 to 4 carbon atoms, X is halogen or a compound with the general formula OSL ⁴ , where K ⁴ is alkyl a radical with 1 to 6 carbon atoms or

25 an aryl radical with 6 to 12 carbon atoms, as a carbonate filler, contains at least one substance ιη compounds with the general formula MxCO3, where M is ΝaH. ΝΙΙα, Νa, K, Ca, Μ &, Ba, x - 1 or 2. with the following ratio of components (in May. Parts): 3 organosiloxane rubber - 100 organosilicon crosslinking ages - 5 - 30 carbonate filler - 20 - 120. \ ΥΟ 97/44381 _{1 β} ΡСΤ / ΙШ96 / 00194

2. The composition according to claim 1, characterized in that it further comprises from 60 to 150 parts of aluminum hydroxide.

3. The composition according to claim 1, characterized in that it further comprises from 0.01 to 0.5 parts of tin dialkylsulfarboxylate of the general formula:

K ⁵ is an alkyl radical with 2 to 4 carbon atoms, K ⁶ is an alkyl radical with 8 to 12 carbon atoms.

4. The composition according to π.1, characterized in that it further comprises from 0.01 to 0.3 parts of dispersed boron with a specific surface area of 3 to 10 m ² / g and particle sizes in the range from 0.2 to 20 microns.

5. The composition according to claim 2, characterized in that the aluminum hydroxide is used in powder form with particle sizes in the range from 0.5 to 10 microns.

6. The composition according to p. 1, characterized in that it contains from 0.01 to 0.3 may. including at least one compound from the group: Β ₂ Οз, НзВОз. TϊV ?, 8ϊϊΒ ₄ , Α1Β.