CA1141060A - Elastomeric organopolysiloxanes containing polycarbodiimide-polysiloxane copolymers - Google Patents
Elastomeric organopolysiloxanes containing polycarbodiimide-polysiloxane copolymersInfo
- Publication number
- CA1141060A CA1141060A CA000338809A CA338809A CA1141060A CA 1141060 A CA1141060 A CA 1141060A CA 000338809 A CA000338809 A CA 000338809A CA 338809 A CA338809 A CA 338809A CA 1141060 A CA1141060 A CA 1141060A
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- Prior art keywords
- polycarbodiimide
- polysiloxane
- peroxide
- organopolysiloxane
- polysiloxane copolymer
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
- C08L83/04—Polysiloxanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/22—Polysiloxanes containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen
- C08G77/24—Polysiloxanes containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen halogen-containing groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/22—Polysiloxanes containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen
- C08G77/26—Polysiloxanes containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen nitrogen-containing groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/42—Block-or graft-polymers containing polysiloxane sequences
- C08G77/452—Block-or graft-polymers containing polysiloxane sequences containing nitrogen-containing sequences
- C08G77/455—Block-or graft-polymers containing polysiloxane sequences containing nitrogen-containing sequences containing polyamide, polyesteramide or polyimide sequences
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Bayer 3740-LH:fv ELASTOMERIC ORGANOPOLYSILOXANES CONTAINING
POLYCARBODIIMIDE-POLYSILOXANE COPOLYMERS
ABSTRACT
A composition which is heat-curable to give an elastomer of improved resistance to hydrolytic degradation comprising a) an organopolysiloxane polymer having a viscosity of about 1,000,000 to 200,000,000 mPas at 25°C and comprising a structural unit of the formula wherein R is a monovalent hydrocarbon, halohydrocarbon or cyanohydrocarbon, and a is between about 1.95 and 2.01, b) a polycarbodiimide-polysiloxane copolymer, c) a curing catalyst, and d) a filler, The polycarbodiiamide-polysiloxane copolymer is responsible for improved stability and preferably the polysiloxane and poly-carbodiimide components of the copolymer are present as distinguishable phases.
Le A 19 083 -US
POLYCARBODIIMIDE-POLYSILOXANE COPOLYMERS
ABSTRACT
A composition which is heat-curable to give an elastomer of improved resistance to hydrolytic degradation comprising a) an organopolysiloxane polymer having a viscosity of about 1,000,000 to 200,000,000 mPas at 25°C and comprising a structural unit of the formula wherein R is a monovalent hydrocarbon, halohydrocarbon or cyanohydrocarbon, and a is between about 1.95 and 2.01, b) a polycarbodiimide-polysiloxane copolymer, c) a curing catalyst, and d) a filler, The polycarbodiiamide-polysiloxane copolymer is responsible for improved stability and preferably the polysiloxane and poly-carbodiimide components of the copolymer are present as distinguishable phases.
Le A 19 083 -US
Description
ELASTOMERIC ORGANOPOLYSILOXANES CONTAINING POLYCARBO-: DIIMID~-POLYSILOXANE COPOLYMERS
The present invention relates to compositions which can be heat-cured to give elastomers; the compositions have improved resistance to hydrolytic degradation and are based on highly viscous organopolysiloxane compositions, with the addition of polycarbodiimide-polysiloxane copoly-mers.
It is known that organopolysiloxane elastomers, for example polydimethylsiloxane rubbers, retain their elasto-meric properties over a wide temperature range. Because of these properties, they have found numerous applications.
However, a difficulty w~ich continues to exist in the field o~ siloxane elastomer technology is the degrada-tion of the polymer structure if the elastomer is exposed to certain environmental conditions for a long time.
For example~ with some polysiloxane elastomers, when used as sealing materials in certain systems, hydrolytic degradation occurs to such an extent that there is consider-able loss of their elastomeric properties. In the absence of atmospheric oxygen the degradation takes place so rapidly that, for example, vulcanize~ polydimethyl-siloxane polymers heated in a sealed tube at 200C as a rule are completely destroyed a~ter only 3 days.
Admittedly, it is known (compare, for example, French Patent Specification 1,440,466 and U.S. Patent Speci~ication 3,031,430) that certain metals and metal com-pounds retard hydrolytic degradation and hence act as stabilizers; for example, bismuth and cadmium, incorpora-ted in the form o~ a low-melting alloy, provide a good pro-tective ef~ect, but the use of these metals in siloxane elastomers suffers from disadvantages. Furthermore, stabilization against thermal ageing is possible, for example by adding iron oxide or iron hydroxide in small amounts (0.001 to 0.75 part by weight per 100 parts by weigh~ o~ silicone elastomer), o~ by adding nickel salts, such as nickel chloride, nickel acetate or nickel octoate.
However, all these known additives produce only inade~uate stabilization of organopolysiloxane polymers against Le A 19 083 ,...~,,~
hydrolytic degradation. Dicyclohexylcarbodiimide, used in rubber tecnnology to protect certain elastomers against hydrolytic degradation, disperses so poorly when incorpora-ted into silicone rubber that it has not been possible to observe a protective effect.
It was therefore the object of the present invention to provide novel advantageous organopolysiloxane elastomers which are resistant to hydrolytic degradation and which exhibit the heat resistance, solvent resistance and mechani~
cal ~a~ior of known polysiloxane elastomers.
Accordingly, the present invention relates to com-positions which are heat-curable to give elastomers, have improved resistance to hydrolytic degradation and are based on organopolysiloxanes, and which are characterized by the following constituents:
a) an organopolysiloxane polymer having a viscosity of ; 1,000,000 to-~200,~00,0~0 mPas at 25C and comprising the ; structural units (R)a SiO4_a wherein R represents a monovalent hydrocarbon radical, which can optionally be halogen-substituted, and a is between a~out 1.95 and 2.01, b) polycarbodiimide-polysiloxane copolymers, c) a curing catalyst and d) ~illers.
The compositions according to the invention, which are heat-curable to give elastomers, can for example con-sist of highly viscous organopolysiloxanes which are in themselves known, especially those cont~ng about ~5 to 100 1 per cent of methylvinylsiloxane units and/or dimethylvinyl-siloxane units, mixed with reinforcing and/or non-reinforc-ing fillers and in most cases also with agents for reducing the stiffening-up l~hich occurs on storage, especially organosilanols and/or organosiloxanols, and curing agents.
The radicals R in the organopolysiloxane polymer or the mixtures of such organopolysiloxane polymers and Le A 19 083 -- 3 ~
especially in a diorganopolysiloxane polymer having a vis-cosity of ~x~t 1,000,000 to 200,000,OGO centipoise at 25C are 'selected,'~for example, from'amongst monovalent hydrocarbon radicals, halogen-substituted-monovalent hydrocarbon radi-cals and cyanoalkyl radicals. Such radicals are, forexample alkyl radicals, such as methyl, ethyl and propyl, cycloalkyl radicals, such as cyclohexyl and cycloheptyl, alkenyl radicals, such as vinyl and allyl, halogen-substitu-ted alkyl radicals, such as fluoropropyl and trifluoro-propyl and in particular fluorinated alkyl radicals of theformula R4CH2CH2-, R4 being a perfluoroalkyl radical, mono-nuclear aryl radicals, such as phenyl, alkaryl radicals, such as methylphenyl and ethylphenyl, aralkyl radicals, such as phenylmethyl and phenylethyl, cyanoalkyl radicals, such as cyanopropyl and the like, as well as other ~ubstituents which are usually encountered as substituents of linear diorganopolysiloxanes. It is particularly preferred to select the radicals R from amongst alkyl radicals with 1 to 8 carbon atoms, alkenyl radicals with 2 to 8 carbon atoms, halogen-substituted alkyl radicals, such as fluoroalkyl radicals with 3 to 8 carbon atoms, and mononuclear aryl radicals.
Further additives used as a rule are pigments, an~i-oxidants and hot air stabilizers based on known metal oxides.
Examples of reinforcing fillers are, in particular, silicon dioxide produced pyrogenically in the gas phase, precipita-ted 3ilicon dioxide having a surface area of at least 50 m2/g, and silicic acid hydrogels dehydrated' in such a way as to retain the structure. Examples of non-rein-forcing fillers are, in particular, diatomaceous earth,quartz powder and chalk. Titanium dioxides, iron oxide, A1203, CaC03, silicates and the like are also suitable.
Examples of curing agents are alkyl peroxides, aryl peroxides or acyl peroxides, used individually or in com-bination. However, the organopolysiloxane compositionscan also be cured by gamma-rays.
The specific peroxide curing catalysts which are preferred include di-tertiary-butyl peroxide, tertiary-butyl triethylmethyl perGxide, tertiary-butyl triphenyl-Le A 19 083 .... .. .. . . . ..
-- 4 ~
methyl peroxide, tertiary-butyl perbenzoate and di-tertiary-alkyl peroxides, such as dicumyl peroxide. ~ther suit-able peroxide catalysts which cause curing both via satura-ted and via unsaturated hydrocarbon groups on the silicone chain are aryl peroxides, the benzoyl peroxides, mixed alkyl-aryl peroxides, such as tertiary-butyl perbenzoate, chloro-aroylperoxides. such as 1.4-dichlorobenzovl peroxide Z 4-dichlorobenzoyl percKide and moncchlor~zGyl peroxide, benzcylperoxide ~ methyl ethyl ketone peroxide and the like. In general, 0.1 ~o 8% by weight of the peroxide, relative to the rubber, are employed. Preferably, about 0.5 to 4 % by weight are employed.
The choice of the crosslinking agent depends on the processing conditions. Thus, for example, most peroxides are employed for w lcanization under pressure at tempera-tures above 100C. In industrial practice, bis-(2,/l dichlorobenzoyl) peroxide has proved a valuable peroxide which, during vulcanization without externally applied pressure, gives bubble-free and pore-freevulcanized products.
Since the peroxides used belong to different chemi-cal categories of compounds, their decomposition products exert different effects in silicone rubber which as a rule adversely influence the pattern of properties of the sili-cone rubber. In particular, the acids liberated on decomposition of acyl peroxides and per esters accelerate thedepolymerization of silicone polymers. The cause for this is a shift in the pH value, which favors attack by water in every form.
According to the present invention, effective pro-tection against the deterioration of the pattern o~ proper-ties of organopolysiloxane rubber materials under hydroly-tic environmental conditions is achieved by using siloxane polymers which contain polycarbodiimide groups.
This finding was surprising inasmuch as the incor-poration of monomeric carbodiimides, such as, ~or example, dicyclohexylcarbodiimide, or of mixtures of higher-mole-cular carbodiimides, such as are employed in the plastics industry as agents for protecting certain polyester-based v or polyether-based polymers against hydrolysis, provided in~ffective in silicone rubber.
Furthermore, it was surprising that the good hot air resistance of silicone rubber is not adversely affected by the presence of the relatively large organic radicals of the poly-carbodiimide constituent.
Suitable polycarbodiimide-polysiloxane copolymers are modified polysiloxanes such as are described, for example, in our copendlng Canadian Applica~ion No. 306,352, filed June 5, 1978, and United States Patent No. 4,076,763. It is preferred to employ those copolymers in which the polysiloxanes and polycarbodiimide are present as distinguishable phases, optionally with partial chemical and/or physical bonding.
The improved organopolysiloxane compositions according to the present invention are, accordingly, polysiloxanes which contain polycarbodiimide-filled organopolysiloxane mixtures which in turn are composed of the following two phases: (i) a continuous phase of an organopolysiloxane liquid and (ii) a discontinuous phase of finely dispersed par-ticles of a carbodiimide polymer which has been obtained by polycondensation of the corresponding monomer or monomer mixture in the presence of the organopolysiloxane and of a carbodiimidation catalyst.
The polycarbodiimide-filled organopolysiloxane compositions are prepared, for example, by thoroughly mixing the organopoly-siloxane liquid with diisocyanates or polyisocyanates or mixtures thereof in the presence of a catalyst which accelerates the carbodiimide formation, or by mixing the organopolysiloxane liquid ~, with polycarbodiimides prepared in situ and in themselves known.
The polymer mixture contains about 3-80% by weight, preferably about 5-70% by weight, of polycarbodiimide (based on the total mixture).
Instead of starting from pure polymer it is possible to employ mixtures of customary polysiloxanes with polycarbodiimide-polysiloxane copolymers. This can be done by premixing polymers with one another and then mixing with -5a-` - 6 -the fillers and auxiliaries already mentioned, or by blending a premix of a customary polysiloxane polymer, fillers and auxiliaries, with the polycarbodiimide polymer, or by premixing polycarbodiimide-polysiloxane polymer with fillers and auxiliaries, or by blending premixes of both types of polymers with one another in the desired ratio.
It follows from the above that the sequence of mixing is not critical.
Equally, the mixing temperature is not subject to any special res-trictions. All procedures customary with silicone rubber can also be employed in the present case.
To prepare the compositions according to the inven--tion, a polycarbcdiimide content of about 0.1 to 70 % by weight, pre-ferably abcut 1 to 20 % by weight, and very particularly prefentially a~out 6 to 15 - by weight, relative to total polymer, is employed.
If the content of polycarbodiimide in the polymer is greater than abcut 70 mol per cent, technical disadvantages in respect of processability manifest themselves, since, in order to achieve satisfactory vulcanization characteristics, either uneconomically large amounts of peroxide-must be employed or the polymer must contain several times the usual content of vin~l groups. Furthermore, the high content of rigid molecular unit structures causes deteriora-tion of the elastomeric properties.
The examples which follow are intended to explainthe silicone elastomers according to the invention in more detail. Mixtures o~ the abovementioned type were pro-duced under the usual conditions on a rubber mixing mill.
The composition of the samples is given in parts by weight.
The test specimens were vulcanized in a heated press.
The test specimens were examined in accordance with the ~ollowing standard specifications:
Strength, elongation, 100 and 300~0 modulus:
DIN 53,504.
Hardness: DIN 53,505.
Elasticity: DIN 53,512~
Tear propagation resistance (crescent): ASTM-D
624 B.
Le A 19 083 Example l This example illustrates a method of preparation of the polycarbodiimide-polysiloxane copolymer.
For this preparation, 20 kg of a polydimethylsilox-ane with terminal hydroxyl groups, having a viscosity Gf10,000 mPas are stirred by means of a stirring disc at 400 to 500 rpm, and warmed to 70C. 30 g of a l-meth~lphos-pholine oxide isomer mixture are added and 20 kg of an isomer mixture of 80 per cent of toluylene-2,4-diisocyanate and 20 per cent of toluylene-2,6-diisocyanate are metered into this mixture in a uniform stream over the course of 2 hours, with constant stirring. The carbon dioxide formed is led away. After completion of the addition of the isocyanate, stirring is continued for one hour at the same temperature, after ~hich the product is cooled to room tem-perature.
The product is a white to pale yellowish, viscous composition having a viscosity of about 200,000 mPas.
xample 2 This example describes the preparation of a poly-carbodiimide-polysiloxane copolymer based on diphenyl-methane-4,4'-diisocyanate~
750 g of polydimethylsiloxane with terminal hydroxyl groups and having a viscosity of 18,000 mPas are heated to 80C and o.6 ml of l~methyl-phospholine oxide iso~er mixture is added. 750 g of diphenylmethane-4,4'-diisocyanate are mete~d in over the course of 2 hours at 80C, with constant stirring, and after completion of the addition stirring is continued for 1 hour at 80C. A white, homogeneous and pourable product having a viscosity of 330,000 mPas is obtained.
E~ es 3 to 8 A silicone rubber premix is prepared on a rubber mixing mill by mixing, in the usual manner, l part of hexa-methyldisilazane, 58 parts of a pyrogenic silica having asurface area of 200 m2/g and 12.76 parts of a silicone oil containing hydroxyl groups and possessing 3.1 mol % of vinyl-methyl-siloxane units into lO0 parts of a polydi-methylsiloxane containing vinyl groups (0.003 mol ,b of Le A 19 083 .. .. . . . . . . . . ... . . .. . . .
; - 8 -vinyl-methyl groups3.
This premix is divided Into six parts and each is mixed, on a rubber mixing mill, with a 50 ~ strength Dis-(2,4-dichlorobenzoyl) peroxide paste in silicone oil, and, optionally, with a polycarbo~iimide-polysiloxane copolymer according to Example 1 or dicyclohexylcarbodiimide, in accordance with Table 1 below.
Sheets of 2 and 6 mm thickness of these six mixtures are vulcanized in a heated press at 120Co The vulcan-ization time is 10 minutes. The test specimens accord-ing to the abovementioned standard specifications are cut from these sheets. Post-vulcanization in hot air is dispensed with, so that the concentration of crosslinking agent decomposition products in the vulcanized materials should be preserved, This is done in order deliberately to create more severe ageing conditions.
The test specimens are examined in accordance with the abovementioned DIN or ASTM instructions. Some o~
the samples are aged, after vulcanization, for 70 or 120 hours at 200C in sealed glass tubes, and are then tested in accordance with the abovementioned DIN instructions.
The progress of hydrolytic ageing is followed by measuring the strengths.
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Examples 9 to 11 100 partC of a polydimethylsiloxane containlng vinyl groups, 1 part of hexamethyldisilazane, 58.0 parts of a pyrogenic silica having a surface area of 200 m2/g, 12.8 parts of a polydimethylsiloxane oil containing hydroxyl groups, 2 parts of a 50% strength paste of black iron oxide pigment in polydimethylsiloxane containing vinyl groups, and 0.8 part of bis-tert.-butyl-(peroxydiisopropyl)-benzene are mixed on a mill, in one and the same pass, with the amounts, shown in Table 2, of polycarbodiimide-polysiloxane polymer according to Example 1 and of a 50% strength bis~
(2,4-dichlorobenzoyl) peroxide paste.
The present invention relates to compositions which can be heat-cured to give elastomers; the compositions have improved resistance to hydrolytic degradation and are based on highly viscous organopolysiloxane compositions, with the addition of polycarbodiimide-polysiloxane copoly-mers.
It is known that organopolysiloxane elastomers, for example polydimethylsiloxane rubbers, retain their elasto-meric properties over a wide temperature range. Because of these properties, they have found numerous applications.
However, a difficulty w~ich continues to exist in the field o~ siloxane elastomer technology is the degrada-tion of the polymer structure if the elastomer is exposed to certain environmental conditions for a long time.
For example~ with some polysiloxane elastomers, when used as sealing materials in certain systems, hydrolytic degradation occurs to such an extent that there is consider-able loss of their elastomeric properties. In the absence of atmospheric oxygen the degradation takes place so rapidly that, for example, vulcanize~ polydimethyl-siloxane polymers heated in a sealed tube at 200C as a rule are completely destroyed a~ter only 3 days.
Admittedly, it is known (compare, for example, French Patent Specification 1,440,466 and U.S. Patent Speci~ication 3,031,430) that certain metals and metal com-pounds retard hydrolytic degradation and hence act as stabilizers; for example, bismuth and cadmium, incorpora-ted in the form o~ a low-melting alloy, provide a good pro-tective ef~ect, but the use of these metals in siloxane elastomers suffers from disadvantages. Furthermore, stabilization against thermal ageing is possible, for example by adding iron oxide or iron hydroxide in small amounts (0.001 to 0.75 part by weight per 100 parts by weigh~ o~ silicone elastomer), o~ by adding nickel salts, such as nickel chloride, nickel acetate or nickel octoate.
However, all these known additives produce only inade~uate stabilization of organopolysiloxane polymers against Le A 19 083 ,...~,,~
hydrolytic degradation. Dicyclohexylcarbodiimide, used in rubber tecnnology to protect certain elastomers against hydrolytic degradation, disperses so poorly when incorpora-ted into silicone rubber that it has not been possible to observe a protective effect.
It was therefore the object of the present invention to provide novel advantageous organopolysiloxane elastomers which are resistant to hydrolytic degradation and which exhibit the heat resistance, solvent resistance and mechani~
cal ~a~ior of known polysiloxane elastomers.
Accordingly, the present invention relates to com-positions which are heat-curable to give elastomers, have improved resistance to hydrolytic degradation and are based on organopolysiloxanes, and which are characterized by the following constituents:
a) an organopolysiloxane polymer having a viscosity of ; 1,000,000 to-~200,~00,0~0 mPas at 25C and comprising the ; structural units (R)a SiO4_a wherein R represents a monovalent hydrocarbon radical, which can optionally be halogen-substituted, and a is between a~out 1.95 and 2.01, b) polycarbodiimide-polysiloxane copolymers, c) a curing catalyst and d) ~illers.
The compositions according to the invention, which are heat-curable to give elastomers, can for example con-sist of highly viscous organopolysiloxanes which are in themselves known, especially those cont~ng about ~5 to 100 1 per cent of methylvinylsiloxane units and/or dimethylvinyl-siloxane units, mixed with reinforcing and/or non-reinforc-ing fillers and in most cases also with agents for reducing the stiffening-up l~hich occurs on storage, especially organosilanols and/or organosiloxanols, and curing agents.
The radicals R in the organopolysiloxane polymer or the mixtures of such organopolysiloxane polymers and Le A 19 083 -- 3 ~
especially in a diorganopolysiloxane polymer having a vis-cosity of ~x~t 1,000,000 to 200,000,OGO centipoise at 25C are 'selected,'~for example, from'amongst monovalent hydrocarbon radicals, halogen-substituted-monovalent hydrocarbon radi-cals and cyanoalkyl radicals. Such radicals are, forexample alkyl radicals, such as methyl, ethyl and propyl, cycloalkyl radicals, such as cyclohexyl and cycloheptyl, alkenyl radicals, such as vinyl and allyl, halogen-substitu-ted alkyl radicals, such as fluoropropyl and trifluoro-propyl and in particular fluorinated alkyl radicals of theformula R4CH2CH2-, R4 being a perfluoroalkyl radical, mono-nuclear aryl radicals, such as phenyl, alkaryl radicals, such as methylphenyl and ethylphenyl, aralkyl radicals, such as phenylmethyl and phenylethyl, cyanoalkyl radicals, such as cyanopropyl and the like, as well as other ~ubstituents which are usually encountered as substituents of linear diorganopolysiloxanes. It is particularly preferred to select the radicals R from amongst alkyl radicals with 1 to 8 carbon atoms, alkenyl radicals with 2 to 8 carbon atoms, halogen-substituted alkyl radicals, such as fluoroalkyl radicals with 3 to 8 carbon atoms, and mononuclear aryl radicals.
Further additives used as a rule are pigments, an~i-oxidants and hot air stabilizers based on known metal oxides.
Examples of reinforcing fillers are, in particular, silicon dioxide produced pyrogenically in the gas phase, precipita-ted 3ilicon dioxide having a surface area of at least 50 m2/g, and silicic acid hydrogels dehydrated' in such a way as to retain the structure. Examples of non-rein-forcing fillers are, in particular, diatomaceous earth,quartz powder and chalk. Titanium dioxides, iron oxide, A1203, CaC03, silicates and the like are also suitable.
Examples of curing agents are alkyl peroxides, aryl peroxides or acyl peroxides, used individually or in com-bination. However, the organopolysiloxane compositionscan also be cured by gamma-rays.
The specific peroxide curing catalysts which are preferred include di-tertiary-butyl peroxide, tertiary-butyl triethylmethyl perGxide, tertiary-butyl triphenyl-Le A 19 083 .... .. .. . . . ..
-- 4 ~
methyl peroxide, tertiary-butyl perbenzoate and di-tertiary-alkyl peroxides, such as dicumyl peroxide. ~ther suit-able peroxide catalysts which cause curing both via satura-ted and via unsaturated hydrocarbon groups on the silicone chain are aryl peroxides, the benzoyl peroxides, mixed alkyl-aryl peroxides, such as tertiary-butyl perbenzoate, chloro-aroylperoxides. such as 1.4-dichlorobenzovl peroxide Z 4-dichlorobenzoyl percKide and moncchlor~zGyl peroxide, benzcylperoxide ~ methyl ethyl ketone peroxide and the like. In general, 0.1 ~o 8% by weight of the peroxide, relative to the rubber, are employed. Preferably, about 0.5 to 4 % by weight are employed.
The choice of the crosslinking agent depends on the processing conditions. Thus, for example, most peroxides are employed for w lcanization under pressure at tempera-tures above 100C. In industrial practice, bis-(2,/l dichlorobenzoyl) peroxide has proved a valuable peroxide which, during vulcanization without externally applied pressure, gives bubble-free and pore-freevulcanized products.
Since the peroxides used belong to different chemi-cal categories of compounds, their decomposition products exert different effects in silicone rubber which as a rule adversely influence the pattern of properties of the sili-cone rubber. In particular, the acids liberated on decomposition of acyl peroxides and per esters accelerate thedepolymerization of silicone polymers. The cause for this is a shift in the pH value, which favors attack by water in every form.
According to the present invention, effective pro-tection against the deterioration of the pattern o~ proper-ties of organopolysiloxane rubber materials under hydroly-tic environmental conditions is achieved by using siloxane polymers which contain polycarbodiimide groups.
This finding was surprising inasmuch as the incor-poration of monomeric carbodiimides, such as, ~or example, dicyclohexylcarbodiimide, or of mixtures of higher-mole-cular carbodiimides, such as are employed in the plastics industry as agents for protecting certain polyester-based v or polyether-based polymers against hydrolysis, provided in~ffective in silicone rubber.
Furthermore, it was surprising that the good hot air resistance of silicone rubber is not adversely affected by the presence of the relatively large organic radicals of the poly-carbodiimide constituent.
Suitable polycarbodiimide-polysiloxane copolymers are modified polysiloxanes such as are described, for example, in our copendlng Canadian Applica~ion No. 306,352, filed June 5, 1978, and United States Patent No. 4,076,763. It is preferred to employ those copolymers in which the polysiloxanes and polycarbodiimide are present as distinguishable phases, optionally with partial chemical and/or physical bonding.
The improved organopolysiloxane compositions according to the present invention are, accordingly, polysiloxanes which contain polycarbodiimide-filled organopolysiloxane mixtures which in turn are composed of the following two phases: (i) a continuous phase of an organopolysiloxane liquid and (ii) a discontinuous phase of finely dispersed par-ticles of a carbodiimide polymer which has been obtained by polycondensation of the corresponding monomer or monomer mixture in the presence of the organopolysiloxane and of a carbodiimidation catalyst.
The polycarbodiimide-filled organopolysiloxane compositions are prepared, for example, by thoroughly mixing the organopoly-siloxane liquid with diisocyanates or polyisocyanates or mixtures thereof in the presence of a catalyst which accelerates the carbodiimide formation, or by mixing the organopolysiloxane liquid ~, with polycarbodiimides prepared in situ and in themselves known.
The polymer mixture contains about 3-80% by weight, preferably about 5-70% by weight, of polycarbodiimide (based on the total mixture).
Instead of starting from pure polymer it is possible to employ mixtures of customary polysiloxanes with polycarbodiimide-polysiloxane copolymers. This can be done by premixing polymers with one another and then mixing with -5a-` - 6 -the fillers and auxiliaries already mentioned, or by blending a premix of a customary polysiloxane polymer, fillers and auxiliaries, with the polycarbodiimide polymer, or by premixing polycarbodiimide-polysiloxane polymer with fillers and auxiliaries, or by blending premixes of both types of polymers with one another in the desired ratio.
It follows from the above that the sequence of mixing is not critical.
Equally, the mixing temperature is not subject to any special res-trictions. All procedures customary with silicone rubber can also be employed in the present case.
To prepare the compositions according to the inven--tion, a polycarbcdiimide content of about 0.1 to 70 % by weight, pre-ferably abcut 1 to 20 % by weight, and very particularly prefentially a~out 6 to 15 - by weight, relative to total polymer, is employed.
If the content of polycarbodiimide in the polymer is greater than abcut 70 mol per cent, technical disadvantages in respect of processability manifest themselves, since, in order to achieve satisfactory vulcanization characteristics, either uneconomically large amounts of peroxide-must be employed or the polymer must contain several times the usual content of vin~l groups. Furthermore, the high content of rigid molecular unit structures causes deteriora-tion of the elastomeric properties.
The examples which follow are intended to explainthe silicone elastomers according to the invention in more detail. Mixtures o~ the abovementioned type were pro-duced under the usual conditions on a rubber mixing mill.
The composition of the samples is given in parts by weight.
The test specimens were vulcanized in a heated press.
The test specimens were examined in accordance with the ~ollowing standard specifications:
Strength, elongation, 100 and 300~0 modulus:
DIN 53,504.
Hardness: DIN 53,505.
Elasticity: DIN 53,512~
Tear propagation resistance (crescent): ASTM-D
624 B.
Le A 19 083 Example l This example illustrates a method of preparation of the polycarbodiimide-polysiloxane copolymer.
For this preparation, 20 kg of a polydimethylsilox-ane with terminal hydroxyl groups, having a viscosity Gf10,000 mPas are stirred by means of a stirring disc at 400 to 500 rpm, and warmed to 70C. 30 g of a l-meth~lphos-pholine oxide isomer mixture are added and 20 kg of an isomer mixture of 80 per cent of toluylene-2,4-diisocyanate and 20 per cent of toluylene-2,6-diisocyanate are metered into this mixture in a uniform stream over the course of 2 hours, with constant stirring. The carbon dioxide formed is led away. After completion of the addition of the isocyanate, stirring is continued for one hour at the same temperature, after ~hich the product is cooled to room tem-perature.
The product is a white to pale yellowish, viscous composition having a viscosity of about 200,000 mPas.
xample 2 This example describes the preparation of a poly-carbodiimide-polysiloxane copolymer based on diphenyl-methane-4,4'-diisocyanate~
750 g of polydimethylsiloxane with terminal hydroxyl groups and having a viscosity of 18,000 mPas are heated to 80C and o.6 ml of l~methyl-phospholine oxide iso~er mixture is added. 750 g of diphenylmethane-4,4'-diisocyanate are mete~d in over the course of 2 hours at 80C, with constant stirring, and after completion of the addition stirring is continued for 1 hour at 80C. A white, homogeneous and pourable product having a viscosity of 330,000 mPas is obtained.
E~ es 3 to 8 A silicone rubber premix is prepared on a rubber mixing mill by mixing, in the usual manner, l part of hexa-methyldisilazane, 58 parts of a pyrogenic silica having asurface area of 200 m2/g and 12.76 parts of a silicone oil containing hydroxyl groups and possessing 3.1 mol % of vinyl-methyl-siloxane units into lO0 parts of a polydi-methylsiloxane containing vinyl groups (0.003 mol ,b of Le A 19 083 .. .. . . . . . . . . ... . . .. . . .
; - 8 -vinyl-methyl groups3.
This premix is divided Into six parts and each is mixed, on a rubber mixing mill, with a 50 ~ strength Dis-(2,4-dichlorobenzoyl) peroxide paste in silicone oil, and, optionally, with a polycarbo~iimide-polysiloxane copolymer according to Example 1 or dicyclohexylcarbodiimide, in accordance with Table 1 below.
Sheets of 2 and 6 mm thickness of these six mixtures are vulcanized in a heated press at 120Co The vulcan-ization time is 10 minutes. The test specimens accord-ing to the abovementioned standard specifications are cut from these sheets. Post-vulcanization in hot air is dispensed with, so that the concentration of crosslinking agent decomposition products in the vulcanized materials should be preserved, This is done in order deliberately to create more severe ageing conditions.
The test specimens are examined in accordance with the abovementioned DIN or ASTM instructions. Some o~
the samples are aged, after vulcanization, for 70 or 120 hours at 200C in sealed glass tubes, and are then tested in accordance with the abovementioned DIN instructions.
The progress of hydrolytic ageing is followed by measuring the strengths.
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Examples 9 to 11 100 partC of a polydimethylsiloxane containlng vinyl groups, 1 part of hexamethyldisilazane, 58.0 parts of a pyrogenic silica having a surface area of 200 m2/g, 12.8 parts of a polydimethylsiloxane oil containing hydroxyl groups, 2 parts of a 50% strength paste of black iron oxide pigment in polydimethylsiloxane containing vinyl groups, and 0.8 part of bis-tert.-butyl-(peroxydiisopropyl)-benzene are mixed on a mill, in one and the same pass, with the amounts, shown in Table 2, of polycarbodiimide-polysiloxane polymer according to Example 1 and of a 50% strength bis~
(2,4-dichlorobenzoyl) peroxide paste.
2 and 6 mm thick sheets of these mixtures are vul-canized for 10 minutes in a heated press at 120 to 180C, using rapid heating. The test specimens are cut from these sheets in accordance with standard specifications and are tested appropriately. ~ome of the samples, after having been vulcanized, are heated for 10 days at 200C by means of hot air and others for 3 days at 225C. Yet a further number of the samples are heated for 70 hours in a sealed glass tube at 200C.
Following their vulcanization with or without sub-sequentheat ageing, all the samples are tested in accordance with the DIN instructions. The progress of the hydroly-tic ageing is followed by measuring the strengths.
Table 2 Example 9 Example 10 Example 11 containing vinyl groups100.0lO0.0 100.0 30 Hexamethyldisilazane 1.0 1.0 1.0 Silica 58.0 58.0 58.0 Polydimethylsiloxane 12 8 12 8 12 8 containing hydroxyl groups Iron oxide pigment 2.0 2.0 2.0 35 ~icumyl peroxide 0.8 0.8 0.8 Polycarbodiimide- 4 0 4 0 6 0 polysiloxane copolymer Le A 19 083 , .. .. . ... .. .. . . .. . .
Table 2 (Continuation) Example 9 Example 10 Example 11 .- ., . . . .. .....
Peroxide paste as per 1 4 1 8 1.4 5 text Vulcanization at 120-180C, duration 10' Strength (MPa) 8.5 8.3 7.9 Elongation (%) 450 460 450 10 Modulus (100%) 2.0 2.1 1.9 Modulus (300%) 5.4 5.4 5.0 Hardness (Shore A) 63 64 63 Elasticity (%) 37 31 29 Crescent (N/mm) 18 21 21 Vulcanization 120-* 180C7 10' + 10 days at 200C in hot air Strength 5.2 5.4 5.0 Elongation 250 250 250 20 Modulus ( lOOyo ) 3.1 3.2 3.1 Hardness 71 71 72 Elasticity 23 28 28 Vulcanization 120-~ 180C, _ - 10' + 3 days at 225C in hot air .. _ . .. . . . ..
Strength 4.0 4.5 4.o Elongation 200 240 235 Modulus (100%) 2.9 3.0 3.1 Hardness 69 73 72 30 Elasticity 22 24 24 Vulcan zation 120-~ol80C, 10' + ~0 hrs at 200 C in a sealed test-tube Strength 1.1 1.2 1.6 35 Elongation 40 60 70 Exam~les 12 to 16 A silicone rubber premix is prepared in the usual manner on a ~ubber mixer by adding, to 100 parts of a poly-dimethylsiloxane containing vinyl groups, 27.5 parts o~
Le A 19 083
Following their vulcanization with or without sub-sequentheat ageing, all the samples are tested in accordance with the DIN instructions. The progress of the hydroly-tic ageing is followed by measuring the strengths.
Table 2 Example 9 Example 10 Example 11 containing vinyl groups100.0lO0.0 100.0 30 Hexamethyldisilazane 1.0 1.0 1.0 Silica 58.0 58.0 58.0 Polydimethylsiloxane 12 8 12 8 12 8 containing hydroxyl groups Iron oxide pigment 2.0 2.0 2.0 35 ~icumyl peroxide 0.8 0.8 0.8 Polycarbodiimide- 4 0 4 0 6 0 polysiloxane copolymer Le A 19 083 , .. .. . ... .. .. . . .. . .
Table 2 (Continuation) Example 9 Example 10 Example 11 .- ., . . . .. .....
Peroxide paste as per 1 4 1 8 1.4 5 text Vulcanization at 120-180C, duration 10' Strength (MPa) 8.5 8.3 7.9 Elongation (%) 450 460 450 10 Modulus (100%) 2.0 2.1 1.9 Modulus (300%) 5.4 5.4 5.0 Hardness (Shore A) 63 64 63 Elasticity (%) 37 31 29 Crescent (N/mm) 18 21 21 Vulcanization 120-* 180C7 10' + 10 days at 200C in hot air Strength 5.2 5.4 5.0 Elongation 250 250 250 20 Modulus ( lOOyo ) 3.1 3.2 3.1 Hardness 71 71 72 Elasticity 23 28 28 Vulcanization 120-~ 180C, _ - 10' + 3 days at 225C in hot air .. _ . .. . . . ..
Strength 4.0 4.5 4.o Elongation 200 240 235 Modulus (100%) 2.9 3.0 3.1 Hardness 69 73 72 30 Elasticity 22 24 24 Vulcan zation 120-~ol80C, 10' + ~0 hrs at 200 C in a sealed test-tube Strength 1.1 1.2 1.6 35 Elongation 40 60 70 Exam~les 12 to 16 A silicone rubber premix is prepared in the usual manner on a ~ubber mixer by adding, to 100 parts of a poly-dimethylsiloxane containing vinyl groups, 27.5 parts o~
Le A 19 083
3 ~.41~?~V
. - 13 -pyrogenically produced silica o~ sur~ace area greater than 300 m2/g and 6.33 parts of a silanol-based processing auxiliary, This premix is divided into four parts and mixed on a rubber mixer with polycarbodiimide-polysiloxane copol-ymer according to Example 2 and with a 50% strength biS-(2,L~
dichlorobenzoyl) peroxide paste in silicone oil, in accord-ance with Table 3 below.
2 and 6 mm thick sheets of these mixtures are cross-lb linked in a heated press at 120C, with a vulcanization time of 10 minutes. The test specimens cut from the sheets in accordance with the appropriate standard specifications are tested in accordance with the said specifications.
Some of the samples, after having been vulcanized, are heated for 10 days at 200C by means of hot air and others for 3 days at 225C. Yet a further number of the samples are heated ~or 70 hours in a sealed glass tube at 200C.
Following their vulcanization, with or without subsequent heat ageing, aIl the samples are-tested in accordance with standard specification instructions. The progress of the hydrolytic degradation is followed by measuring the strengths.
.. ~
Example Example Example Example Premix 100.0100.0 100.0 100.0 Polycarbodiimide- 8 0 6 0 4 0 polysiloxane copolymer ~Peroxide paste as per text 1.4 1.0 1.2 1.4 Vulcani~ation for 10'/120UC press temperature Strength (mPa) 7.7 7.0 7.9 8,7 Elongation (%) 555 590 545 490 Modulus (100%) 1.4 1.3 1.5 1.7 Modulus (300/0) 0.7 3.1 4.0 4.7 Hardness (Shore A) 50 54 59 66 Elasticity (%) 19 18 20 25 Crescent (~/mm) 35 36 33 32 ~,~
Table 3 (Continuation) Example Example Exa~ple Example ,. .. . . ..
Vulcanization for 10'/
5 120C press temperature + 10 days at 200C in hot air ., Strength 5 ~ 2 4 ~ 7 4~ 7 5 ~ 1 Elongation 310 325 300 270 10 Modulus ( 100% ) 2 ~ 3 2 ~ 2 2 ~ 4 2 ~ 9 Modulus (200%) 3r7 3~3 3~6 4~3 Hardness 70 71 73 76 Elasticity 23 23 25 28 Vulcanization for 10'/
15 120C press temgerature + 3 days at 225 C in hot air .. . . . _ _ . , , "
- Strength 4~ 8 4~ 4 4~ 8 4~ 9 Elongation 360 335 310 245 20 Modulus (100%) 2 ~ 0 2 ~ 0 2 ~ 4 2 ~ 8 Modulus (200%) 3~0 2~9 3~6 4~2 Hardness 68 68 69 73 Elasticity 16 17 17 22 . . . .
-~ Vulcanization for 10'/
25 120C press temperature + 70 hours at 200C in a test~tube .. . .... ... .. .
Strength 2~ 6 2 ~ 0 1 ~ 3 Elongation 330 260 105 Modulus (100%) 1.1 1.2 1.3 Y~ulu~ ~ 200O
It will ~e appreciated that the instant specification and examples are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention.
' Le A 19 083
. - 13 -pyrogenically produced silica o~ sur~ace area greater than 300 m2/g and 6.33 parts of a silanol-based processing auxiliary, This premix is divided into four parts and mixed on a rubber mixer with polycarbodiimide-polysiloxane copol-ymer according to Example 2 and with a 50% strength biS-(2,L~
dichlorobenzoyl) peroxide paste in silicone oil, in accord-ance with Table 3 below.
2 and 6 mm thick sheets of these mixtures are cross-lb linked in a heated press at 120C, with a vulcanization time of 10 minutes. The test specimens cut from the sheets in accordance with the appropriate standard specifications are tested in accordance with the said specifications.
Some of the samples, after having been vulcanized, are heated for 10 days at 200C by means of hot air and others for 3 days at 225C. Yet a further number of the samples are heated ~or 70 hours in a sealed glass tube at 200C.
Following their vulcanization, with or without subsequent heat ageing, aIl the samples are-tested in accordance with standard specification instructions. The progress of the hydrolytic degradation is followed by measuring the strengths.
.. ~
Example Example Example Example Premix 100.0100.0 100.0 100.0 Polycarbodiimide- 8 0 6 0 4 0 polysiloxane copolymer ~Peroxide paste as per text 1.4 1.0 1.2 1.4 Vulcani~ation for 10'/120UC press temperature Strength (mPa) 7.7 7.0 7.9 8,7 Elongation (%) 555 590 545 490 Modulus (100%) 1.4 1.3 1.5 1.7 Modulus (300/0) 0.7 3.1 4.0 4.7 Hardness (Shore A) 50 54 59 66 Elasticity (%) 19 18 20 25 Crescent (~/mm) 35 36 33 32 ~,~
Table 3 (Continuation) Example Example Exa~ple Example ,. .. . . ..
Vulcanization for 10'/
5 120C press temperature + 10 days at 200C in hot air ., Strength 5 ~ 2 4 ~ 7 4~ 7 5 ~ 1 Elongation 310 325 300 270 10 Modulus ( 100% ) 2 ~ 3 2 ~ 2 2 ~ 4 2 ~ 9 Modulus (200%) 3r7 3~3 3~6 4~3 Hardness 70 71 73 76 Elasticity 23 23 25 28 Vulcanization for 10'/
15 120C press temgerature + 3 days at 225 C in hot air .. . . . _ _ . , , "
- Strength 4~ 8 4~ 4 4~ 8 4~ 9 Elongation 360 335 310 245 20 Modulus (100%) 2 ~ 0 2 ~ 0 2 ~ 4 2 ~ 8 Modulus (200%) 3~0 2~9 3~6 4~2 Hardness 68 68 69 73 Elasticity 16 17 17 22 . . . .
-~ Vulcanization for 10'/
25 120C press temperature + 70 hours at 200C in a test~tube .. . .... ... .. .
Strength 2~ 6 2 ~ 0 1 ~ 3 Elongation 330 260 105 Modulus (100%) 1.1 1.2 1.3 Y~ulu~ ~ 200O
It will ~e appreciated that the instant specification and examples are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention.
' Le A 19 083
Claims (6)
1. A composition which is heat-curable to give and elastomer of improved resistance to hydrolytic degradation comprising a) an organopolysiloxane polymer having a viscosity of about 1,000,000 to 200,000,000 mPas at 25°C and comprising a structural unit of the formula wherein R is a monovalent hydrocarbon, halohydrocarbon or cyanohydrocarbon, and a is between about 1.95 and 2.01, b) a polycarbodiimide-polysiloxane copolymer, c) a curing catalyst, and d) a filler.
2. A composition according to claim 1, in which R
is alkyl or haloalkyl with 1 to 8 carbon atoms, alkenyl with 2 to 8 carbon atoms, or a mononuclear aryl radical.
Le A 19 083 -US
is alkyl or haloalkyl with 1 to 8 carbon atoms, alkenyl with 2 to 8 carbon atoms, or a mononuclear aryl radical.
Le A 19 083 -US
3. A composition according to claim 1, in which R
is methyl, vinyl and/or phenyl.
is methyl, vinyl and/or phenyl.
4. A composition according to claim 1, in which by weight the polycarbodiimide-polysiloxane copolymer comprises about 3-80%, the curing catalyst comprises about 0. 1-8% and is a peroxide, and the polycarbodiimide comprises about 0.1-70%
based on the total polymer weight.
based on the total polymer weight.
5. A composition according to claim 3, in which by weight the polycarbodiimide-polysiloxane copolymer comprises about 5-70%, the curing catalyst comprises about 0.5-4% and is a peroxide, and the polycarbodiimide comprises about 6 to 15%
based on the total polymer weight.
based on the total polymer weight.
6. In the production of an elastomer by heat curing a composition comprising an organopolysiloxane, a curing catalyst and a filler, the improvement which comprises incorpora-ting in such composition a polycarbodiimide-polysiloxane copolymer whereby the resistance to hydrolytic degradation is improved.
Le A 19 083 -US
Le A 19 083 -US
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19782847573 DE2847573A1 (en) | 1978-11-02 | 1978-11-02 | IN THE HEAT OF ELASTOMERIC curable ORGANOPOLYSILOXANES |
| DEP2847573.2 | 1978-11-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1141060A true CA1141060A (en) | 1983-02-08 |
Family
ID=6053716
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000338809A Expired CA1141060A (en) | 1978-11-02 | 1979-10-31 | Elastomeric organopolysiloxanes containing polycarbodiimide-polysiloxane copolymers |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0010709B1 (en) |
| JP (1) | JPS5562962A (en) |
| CA (1) | CA1141060A (en) |
| DE (2) | DE2847573A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19515947A1 (en) * | 1995-05-02 | 1996-11-07 | Huels Silicone Gmbh | Storage-stable, alkoxy-crosslinking RTV1 systems |
| JP2004204146A (en) * | 2002-12-26 | 2004-07-22 | Henkel Loctite Corp | Silicone resin composition |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE755920A (en) * | 1969-09-09 | 1971-02-15 | Bayer Ag | USE OF ISOCYANATES AS ACTIVE LOADS IN PLASTICS |
| US4014851A (en) * | 1973-12-26 | 1977-03-29 | General Electric Company | Polyolefin-filled vinyloranopolysiloxane composition and method of preparation |
| GB1487853A (en) * | 1973-12-26 | 1977-10-05 | Gen Electric | Polymer-filled polysiloxanes |
| DE2445220A1 (en) * | 1974-09-21 | 1976-04-08 | Bayer Ag | MOLDING COMPOUNDS HARDWARE TO ELASTOMERS ON THE BASIS OF POLYSILOXANE-POLYURETHANE MIXED POLYMERS |
| DE2730743A1 (en) * | 1977-07-07 | 1979-01-25 | Bayer Ag | ORGANOPOLYSILOXANES MODIFIED WITH POLYCARBODIIMIDE |
-
1978
- 1978-11-02 DE DE19782847573 patent/DE2847573A1/en not_active Withdrawn
-
1979
- 1979-10-22 DE DE7979104075T patent/DE2963898D1/en not_active Expired
- 1979-10-22 EP EP79104075A patent/EP0010709B1/en not_active Expired
- 1979-10-31 JP JP14003279A patent/JPS5562962A/en active Pending
- 1979-10-31 CA CA000338809A patent/CA1141060A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0010709B1 (en) | 1982-10-20 |
| EP0010709A1 (en) | 1980-05-14 |
| DE2963898D1 (en) | 1982-11-25 |
| JPS5562962A (en) | 1980-05-12 |
| DE2847573A1 (en) | 1980-05-22 |
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