CA2601354A1 - Silicone rubber material - Google Patents
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- CA2601354A1 CA2601354A1 CA002601354A CA2601354A CA2601354A1 CA 2601354 A1 CA2601354 A1 CA 2601354A1 CA 002601354 A CA002601354 A CA 002601354A CA 2601354 A CA2601354 A CA 2601354A CA 2601354 A1 CA2601354 A1 CA 2601354A1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
- H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
- H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
- H01B3/46—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes silicones
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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
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- 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
- C08G77/70—Siloxanes defined by use of the MDTQ nomenclature
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Abstract
The invention relates to a silicone rubber material comprising a mixture of a polyalkylsiloxane (A) and a poly- arylsiloxane (B) . The invention also relates to a method of manufacturing such a material . One application of such a material comprises electrical insulation.
Description
Silicone rubber material FIELD OF THE INVENTION
The present invention relates to a silicone rubber material.
Such a material is particularly useful for widely varying applications at low temperatures. One particularly useful such application is as an insulator for electrical apparatus placed outdoors. The invention also relates to a method for manufacturing such a material.
BACKGROUND OF THE INVENTION
Silicone rubber material is usually based on polyalkyl-siloxane, most often polydimethylsiloxane, designated PDMS
in this application, which in the temperature range of about -35 - 150 C is a chemically and physically stable material, with good mechanical and electrical properties, that may be used for many different technical purposes. Si-licone rubber material is cross-linked, for example, by supplying a suitable organic peroxide that reacts with groups on the main chain of PDMS and hence bond the macro-molecules together. The fundamental chemistry for silicone rubber and its crosslinking is clear, for example, from F
Billmeyer, Textbook of polymer science, John Wiley & Sons Ltd, pp. 482-484. Another way to achieve crosslinking is to add a platinum catalyst that breaks up double bonds on vinyl groups and renders them reaction-prone with respect to adjoining siloxane chains.
It is well known that silicone rubber material is used for different electrical insulation purposes, which is clear, for example, from R Hackham, Outdoor HV Composite Polymeric Insulators, IEEE Trans Dielectrics and Elec. Insul., Vol. 6 (1999), pp. 557-585.
The present invention relates to a silicone rubber material.
Such a material is particularly useful for widely varying applications at low temperatures. One particularly useful such application is as an insulator for electrical apparatus placed outdoors. The invention also relates to a method for manufacturing such a material.
BACKGROUND OF THE INVENTION
Silicone rubber material is usually based on polyalkyl-siloxane, most often polydimethylsiloxane, designated PDMS
in this application, which in the temperature range of about -35 - 150 C is a chemically and physically stable material, with good mechanical and electrical properties, that may be used for many different technical purposes. Si-licone rubber material is cross-linked, for example, by supplying a suitable organic peroxide that reacts with groups on the main chain of PDMS and hence bond the macro-molecules together. The fundamental chemistry for silicone rubber and its crosslinking is clear, for example, from F
Billmeyer, Textbook of polymer science, John Wiley & Sons Ltd, pp. 482-484. Another way to achieve crosslinking is to add a platinum catalyst that breaks up double bonds on vinyl groups and renders them reaction-prone with respect to adjoining siloxane chains.
It is well known that silicone rubber material is used for different electrical insulation purposes, which is clear, for example, from R Hackham, Outdoor HV Composite Polymeric Insulators, IEEE Trans Dielectrics and Elec. Insul., Vol. 6 (1999), pp. 557-585.
To the pure polysiloxanes there may be mixed fillers, both so-called bulk fillers such as, for example, silicon dioxi-de or quartz, and fibre fillers such as, for example, short or long glass fibres. Examples of silicone rubber materials with bulk fillers are clear from EP 1 052 655 B1.
Silicone rubber material, wholly based on PDMS, starts crystallizing at about -40 C and hence the material stiffens and experiences brittleness. For non-crosslinked silicones with a molecular weight of about 2000 u, the so-called freezing point by be lowered by replacing methyl groups on the main chain of PDMS by phenyl groups. Phen.yl groups are larger than methyl groups and hence suppress structural order. This has been described in Warrick et al., Polymer Chemistry of the Linear Siloxanes, Industrial Engineering Chemistry, 1952, p. 2199. However, the cost of polydiarylsiloxane is high relative to polydialkylsiloxane, and for that reason polydiarylsiloxane cannot be used for many electrical applications.
EP 0 470 745 A2 describes that 100 parts by weight of an organopolysiloxane gum, with the formula for the average repeating unit being RaSi04-Ai2, where R is a monovalent hydrocarbon group, with the proportion of alkyl being at least 50 per cent, and a is a number between 1.98 and 2.02, have been mixed with inorganic fillers and 1-20 parts by weight of an organosilane or organosiloxaneoligomers according to the formula R' CH3 I I
OH- -SiO - - -SiO - - H
R 2 m n where m is between 1 and 20 and n is between 0 and 20. In addition, an organic peroxide is added.
Silicone rubber material, wholly based on PDMS, starts crystallizing at about -40 C and hence the material stiffens and experiences brittleness. For non-crosslinked silicones with a molecular weight of about 2000 u, the so-called freezing point by be lowered by replacing methyl groups on the main chain of PDMS by phenyl groups. Phen.yl groups are larger than methyl groups and hence suppress structural order. This has been described in Warrick et al., Polymer Chemistry of the Linear Siloxanes, Industrial Engineering Chemistry, 1952, p. 2199. However, the cost of polydiarylsiloxane is high relative to polydialkylsiloxane, and for that reason polydiarylsiloxane cannot be used for many electrical applications.
EP 0 470 745 A2 describes that 100 parts by weight of an organopolysiloxane gum, with the formula for the average repeating unit being RaSi04-Ai2, where R is a monovalent hydrocarbon group, with the proportion of alkyl being at least 50 per cent, and a is a number between 1.98 and 2.02, have been mixed with inorganic fillers and 1-20 parts by weight of an organosilane or organosiloxaneoligomers according to the formula R' CH3 I I
OH- -SiO - - -SiO - - H
R 2 m n where m is between 1 and 20 and n is between 0 and 20. In addition, an organic peroxide is added.
By organopolysiloxane gum is meant a substituted or un-substituted monovalent hydrocarbon group. Examples of such groups are alkyl, alkenyl, cykloalkyl and aralkyl groups.
According to C.A. Hampel and G.G. Hawley, Glossary of Chemical Terms, Van Nostrand Reinhold Company, 1976, p.
196, oligo is a "prefix derived from Greek, meaning "several" or "slight"; in chemistry it appears in such terms as oligosaccharides (containing from three to ten monosaccharide units) and oligodynamic (slight bactericidal ability)".
EP 1 079 398 A2, Example 1, p. 10, describes that 80 parts by weight dimethylpolysiloxane is grafted with dimethyl-vinylsiloxy groups at both ends of the respective dimethyl-polysiloxane molecule, whereby 40 parts by weight of Si02 filler was also added. 40 parts by weight of this liquid silicone rubber has then, in its turn, been mixed with 60 parts by weight of dimethylpolysiloxane with a lower vis-cosity and a lower degree of polymerization than the one mentioned above and 140 parts by eight aluminium hydroxide.
This latter mixture has then in turn, according to example 4, p. 12, been mixed with 120 parts by weight aluminium hydroxide and 10 parts by weight of a dimethylpolysiloxane-diphenylsiloxane copolymer grafted with dimethylvinylsiloxy groups at both ends of the respective dimethylpolysiloxane-diphenylsiloxane copolymer molecule. The diphenylsiloxane groups make up 20% of the sum of dimethylsiloxane and the diphenylsiloxane groups in the copolymer. Out of the sum of polydimethylsiloxane and polydiphenylsiloxane, the poly-diphenylsiloxane thus constitutes between 2 and 3 per cent by weight. The object of EP 1 079 398 A2 is to create a material that may be used for electrical applications and that have tixotropic properties suitable for sealing and repairing polymeric insulants, p. 2 lines 34-37.
According to C. A. Hampel and G. G. Hawley, Glossary of Chemical Terms, Van Nostrand Reinhold Company, 1976, p. 69, a copolymer is a "high-polymer substance, usually an elas-tomer, made up of two or more different kinds of monomer, for example, styrene and butadiene. Copolymers are made by simultaneous polymerization of monomers in the same opera-tion, usually in emulsion form; as a result, the consti-tuent monomers are combined into a common macromolecule, in contrast to the blending of two separately polymerized monomers".
In S. Wang and J. E. Mark, Reinforcement of elastomeric poly(dimethylsiloxane) by glassy poly(diphenylsiloxane), J.
of Material Science 25 (1990), p. 66, 26.8 per cent by weight poly(diphenylsiloxane) has been mixed into a poly(dimethylsiloxane) network for research reasons.
Similarly, it has been established that there was 6.5 per cent by weight of poly(diphenylsiloxane) in a poly(dimethylsiloxane) network which has been manufactured by in-situ polymerization. No industrial application has been described.
In C. M. Kuo and S. J. Clarson, Investigation of the Interactions and Phase Behavior in Poly(dimethylsiloxane) and Poly(methylphenylsiloxane) Blends, Macromolecules 25(1992), p. 2193, linear poly(dimethylsiloxane) and linear poly(diphenylsiloxane) have been mixed, for research reasons, with a fraction of a volume of poly(dimethyl-siloxane) up to 0.93. No crosslinking is described. No industrial application is described for the use of these mixtures.
For electrical outdoor applications in countries having winter climate, it is required that the material should maintain good mechanical properties down to temperatures of -50 C. This applies, for example, to insulators for elec-trical apparatuses that are placed in the open. Currently, porcelain insulators are used, the mechanical properties of which do not change significantly when the temperature drops from about 100 C to about -50 C. Porcelain insulators have the disadvantage that the material is brittle. This implies, for one thing, that if the insulator due to un-fortunate circumstances, for example by a rapid increase in pressure, is burst form inside, then sharp parts may spread in a neighbouring region, and, for another, that a high 5 mechanical safety factor must be used during mechanical dimensioning. Since porcelain has a relatively high densi-ty, the latter means that porcelain insulators become heavy. Porcelain insulators generally also entail a high cost and the possibilities of tailor-making a geometry for a porcelain insulator requires a considerable contribution in material and process development.
OBJECTS OF THE INVENTION
It is a main object of the present invention to suggest a silicone rubber material that withstands temperatures down to -50 C, and reduces the above-mentioned disadvantages of the prior art.
It is another object of the present invention to obtain better mechanical properties for the silicone rubber material over considerable parts of the temperature range used than hitherto known materials.
SUMMARY OF THE INVENTION
The above objects are achieved with a material as defined in claim 1. The material according to the invention is characterized in that a component A consisting of a polyal-kylsiloxane is mixed with a component B consisting of a polyarylsiloxane. In several respects, polyarylsiloxanes have good properties but are expensive and therefore it is an advantageous solution, also from the cost point of view, to make a mixture. Polyalkylsiloxane in this application means an organopolysiloxane with the following average composition:
According to C.A. Hampel and G.G. Hawley, Glossary of Chemical Terms, Van Nostrand Reinhold Company, 1976, p.
196, oligo is a "prefix derived from Greek, meaning "several" or "slight"; in chemistry it appears in such terms as oligosaccharides (containing from three to ten monosaccharide units) and oligodynamic (slight bactericidal ability)".
EP 1 079 398 A2, Example 1, p. 10, describes that 80 parts by weight dimethylpolysiloxane is grafted with dimethyl-vinylsiloxy groups at both ends of the respective dimethyl-polysiloxane molecule, whereby 40 parts by weight of Si02 filler was also added. 40 parts by weight of this liquid silicone rubber has then, in its turn, been mixed with 60 parts by weight of dimethylpolysiloxane with a lower vis-cosity and a lower degree of polymerization than the one mentioned above and 140 parts by eight aluminium hydroxide.
This latter mixture has then in turn, according to example 4, p. 12, been mixed with 120 parts by weight aluminium hydroxide and 10 parts by weight of a dimethylpolysiloxane-diphenylsiloxane copolymer grafted with dimethylvinylsiloxy groups at both ends of the respective dimethylpolysiloxane-diphenylsiloxane copolymer molecule. The diphenylsiloxane groups make up 20% of the sum of dimethylsiloxane and the diphenylsiloxane groups in the copolymer. Out of the sum of polydimethylsiloxane and polydiphenylsiloxane, the poly-diphenylsiloxane thus constitutes between 2 and 3 per cent by weight. The object of EP 1 079 398 A2 is to create a material that may be used for electrical applications and that have tixotropic properties suitable for sealing and repairing polymeric insulants, p. 2 lines 34-37.
According to C. A. Hampel and G. G. Hawley, Glossary of Chemical Terms, Van Nostrand Reinhold Company, 1976, p. 69, a copolymer is a "high-polymer substance, usually an elas-tomer, made up of two or more different kinds of monomer, for example, styrene and butadiene. Copolymers are made by simultaneous polymerization of monomers in the same opera-tion, usually in emulsion form; as a result, the consti-tuent monomers are combined into a common macromolecule, in contrast to the blending of two separately polymerized monomers".
In S. Wang and J. E. Mark, Reinforcement of elastomeric poly(dimethylsiloxane) by glassy poly(diphenylsiloxane), J.
of Material Science 25 (1990), p. 66, 26.8 per cent by weight poly(diphenylsiloxane) has been mixed into a poly(dimethylsiloxane) network for research reasons.
Similarly, it has been established that there was 6.5 per cent by weight of poly(diphenylsiloxane) in a poly(dimethylsiloxane) network which has been manufactured by in-situ polymerization. No industrial application has been described.
In C. M. Kuo and S. J. Clarson, Investigation of the Interactions and Phase Behavior in Poly(dimethylsiloxane) and Poly(methylphenylsiloxane) Blends, Macromolecules 25(1992), p. 2193, linear poly(dimethylsiloxane) and linear poly(diphenylsiloxane) have been mixed, for research reasons, with a fraction of a volume of poly(dimethyl-siloxane) up to 0.93. No crosslinking is described. No industrial application is described for the use of these mixtures.
For electrical outdoor applications in countries having winter climate, it is required that the material should maintain good mechanical properties down to temperatures of -50 C. This applies, for example, to insulators for elec-trical apparatuses that are placed in the open. Currently, porcelain insulators are used, the mechanical properties of which do not change significantly when the temperature drops from about 100 C to about -50 C. Porcelain insulators have the disadvantage that the material is brittle. This implies, for one thing, that if the insulator due to un-fortunate circumstances, for example by a rapid increase in pressure, is burst form inside, then sharp parts may spread in a neighbouring region, and, for another, that a high 5 mechanical safety factor must be used during mechanical dimensioning. Since porcelain has a relatively high densi-ty, the latter means that porcelain insulators become heavy. Porcelain insulators generally also entail a high cost and the possibilities of tailor-making a geometry for a porcelain insulator requires a considerable contribution in material and process development.
OBJECTS OF THE INVENTION
It is a main object of the present invention to suggest a silicone rubber material that withstands temperatures down to -50 C, and reduces the above-mentioned disadvantages of the prior art.
It is another object of the present invention to obtain better mechanical properties for the silicone rubber material over considerable parts of the temperature range used than hitherto known materials.
SUMMARY OF THE INVENTION
The above objects are achieved with a material as defined in claim 1. The material according to the invention is characterized in that a component A consisting of a polyal-kylsiloxane is mixed with a component B consisting of a polyarylsiloxane. In several respects, polyarylsiloxanes have good properties but are expensive and therefore it is an advantageous solution, also from the cost point of view, to make a mixture. Polyalkylsiloxane in this application means an organopolysiloxane with the following average composition:
R nSi0 (4-n) /2 where R is a substituted or unsubstituted monovalent hydrocarbon group and n is a number between 1.98 and 2.02.
The number of repeating units may be from 100 to 20000. One example of a polyalkylsiloxane is polydimethylsiloxane which constitutes the main part of Powersil 318.
Powersil 318 also contains an organic peroxide for cross-linking Polyarylsiloxane, in this application, means a polydi-methylsiloxane where methyl groups on the main chain in the molecules have been replaced by substituted or unsubstitu-ted phenyl groups according to the below:
R5 R, where Rn, where n=1..5, are aryl or alkyl groups.
One example of a polyarylsiloxane is the main ingredient in Wacker Elastosil R490/55 but for the invention also other phenylated silicone rubber materials may be used.
Elastosil R490/55 also contains an organic peroxide for crosslinking.
A mixture of 1-15 parts by weight of component B per 100 parts by weight of component A gives an improvement of the compliance of the material at -50 C while at the same time reducing the cost compared with a material that only con-tains component B. Experiments and investigations have surprisingly shown that a mixture of 3-10 parts by weight of component B on 100 parts by weight of component A gives a very advantageous reduction of the stiffness coefficient at -50 C while at the same time the cost advantage is par-ticularly great. Nor does such a mixture influence the process properties, as for example the viscosity, when manufacturing components, which is an advantage. Stiffness coefficient in this application means the stiffness co-efficient, so-called storage modulus G', which is measured with an instrument called Dynamical Mechanical Analyser, with the generally accepted abbreviation DMA. The mixture has a viscosity according to Mooney ML (1+4), at 23 C, according to the standard DIN 53523, in the interval of 50-65 M.
The possibility of intermixing different quantities of com-ponent B provides possibilities of customizing process properties, for example viscosity, and mechanical proper-ties, for example the stiffness coefficient.
According to one embodiment of the invention, the materi.al comprises a component C, which is an organic peroxide whose task is to crosslink components A and B in the mixture. An example of an appropriate organic peroxide is bis(2,4-dichlorobenzoyl)peroxide. Component C is added to the mixture in an amount of 0.01-5 parts by weight on 100 parts by weight of component A, preferably of 1-4 parts by weight on 100 parts by weight of component A.
According to another embodiment of the invention, a plati-num catalyst is used to crosslink components A and B in the mixture. Examples of a platinum catalyst that may be uti-lized for crosslinking are various types of a platinum com-plex that are dissolved in, for example, alcohol, xylene, divinylsiloxane, or cyclic vinylsiloxanes. One example of such a platinum complex is a platinum carbonyl cyclovinyl methylsiloxane complex. Preferably, an addition of 0.0005-0.02 parts by weight of a platinum catalyst per 100 parts by weight of components A+B may be used.
According to yet another embodiment of the invention, a component D may also be added to the mixture of component A, component B and component C. Component D comprises different types of fillers to achieve the desired proper-ties. To improve the mechanical strength and the stiffness coefficient, fibre fillers may be used. In this applica-tion, fibre fillers mean a quantity of elongated particles where the extent of the material in the transversal direc-tion is smaller than 0.8 mm. Examples of fibre fillers are short or long glass fibres as well as aramide fibres. zn this application, short fibres mean fibres whose length is shorter than about 3 mm.
To improve the stiffness and the hardness, bulk fillers may be used as fillers. In this application, bulk fillers mean particles whose extent in three mutually perpendicular directions does not differ by more than a factor of 10. The mean particle size is smaller than 3 mm. Examples of bulk fillers are silicon dioxide, aluminium trihydrate, quartz and aluminium oxide. Fibre fillers and bulk fillers other that those mentioned above may also be used to improve the properties of the material.
Preferably, an addition of component D correspondi.ng to a part by weight of 0.3 to 2.5 times the part by weight of component A + B gives a good stiffness of the material. An advantageous embodiment is obtained with an addition of component D corresponding to 0.5 to 1.5 parts by weight per part by weight of components A + B, which gives a very useful combination of stiffness, viscosity and cost.
A particularly advantageous material is obtained if the part by weight of component D is 0.8 to 1.2 times the part by weight of components A + B. This results in a material that has a good stiffness coefficient, especially taking into consideration the need of electric insulators with grooves, a viscosity that makes the material easy to shape, and a low material cost.
A mixture of components according to the invention is par-ticularly useful for electrical insulation.
The number of repeating units may be from 100 to 20000. One example of a polyalkylsiloxane is polydimethylsiloxane which constitutes the main part of Powersil 318.
Powersil 318 also contains an organic peroxide for cross-linking Polyarylsiloxane, in this application, means a polydi-methylsiloxane where methyl groups on the main chain in the molecules have been replaced by substituted or unsubstitu-ted phenyl groups according to the below:
R5 R, where Rn, where n=1..5, are aryl or alkyl groups.
One example of a polyarylsiloxane is the main ingredient in Wacker Elastosil R490/55 but for the invention also other phenylated silicone rubber materials may be used.
Elastosil R490/55 also contains an organic peroxide for crosslinking.
A mixture of 1-15 parts by weight of component B per 100 parts by weight of component A gives an improvement of the compliance of the material at -50 C while at the same time reducing the cost compared with a material that only con-tains component B. Experiments and investigations have surprisingly shown that a mixture of 3-10 parts by weight of component B on 100 parts by weight of component A gives a very advantageous reduction of the stiffness coefficient at -50 C while at the same time the cost advantage is par-ticularly great. Nor does such a mixture influence the process properties, as for example the viscosity, when manufacturing components, which is an advantage. Stiffness coefficient in this application means the stiffness co-efficient, so-called storage modulus G', which is measured with an instrument called Dynamical Mechanical Analyser, with the generally accepted abbreviation DMA. The mixture has a viscosity according to Mooney ML (1+4), at 23 C, according to the standard DIN 53523, in the interval of 50-65 M.
The possibility of intermixing different quantities of com-ponent B provides possibilities of customizing process properties, for example viscosity, and mechanical proper-ties, for example the stiffness coefficient.
According to one embodiment of the invention, the materi.al comprises a component C, which is an organic peroxide whose task is to crosslink components A and B in the mixture. An example of an appropriate organic peroxide is bis(2,4-dichlorobenzoyl)peroxide. Component C is added to the mixture in an amount of 0.01-5 parts by weight on 100 parts by weight of component A, preferably of 1-4 parts by weight on 100 parts by weight of component A.
According to another embodiment of the invention, a plati-num catalyst is used to crosslink components A and B in the mixture. Examples of a platinum catalyst that may be uti-lized for crosslinking are various types of a platinum com-plex that are dissolved in, for example, alcohol, xylene, divinylsiloxane, or cyclic vinylsiloxanes. One example of such a platinum complex is a platinum carbonyl cyclovinyl methylsiloxane complex. Preferably, an addition of 0.0005-0.02 parts by weight of a platinum catalyst per 100 parts by weight of components A+B may be used.
According to yet another embodiment of the invention, a component D may also be added to the mixture of component A, component B and component C. Component D comprises different types of fillers to achieve the desired proper-ties. To improve the mechanical strength and the stiffness coefficient, fibre fillers may be used. In this applica-tion, fibre fillers mean a quantity of elongated particles where the extent of the material in the transversal direc-tion is smaller than 0.8 mm. Examples of fibre fillers are short or long glass fibres as well as aramide fibres. zn this application, short fibres mean fibres whose length is shorter than about 3 mm.
To improve the stiffness and the hardness, bulk fillers may be used as fillers. In this application, bulk fillers mean particles whose extent in three mutually perpendicular directions does not differ by more than a factor of 10. The mean particle size is smaller than 3 mm. Examples of bulk fillers are silicon dioxide, aluminium trihydrate, quartz and aluminium oxide. Fibre fillers and bulk fillers other that those mentioned above may also be used to improve the properties of the material.
Preferably, an addition of component D correspondi.ng to a part by weight of 0.3 to 2.5 times the part by weight of component A + B gives a good stiffness of the material. An advantageous embodiment is obtained with an addition of component D corresponding to 0.5 to 1.5 parts by weight per part by weight of components A + B, which gives a very useful combination of stiffness, viscosity and cost.
A particularly advantageous material is obtained if the part by weight of component D is 0.8 to 1.2 times the part by weight of components A + B. This results in a material that has a good stiffness coefficient, especially taking into consideration the need of electric insulators with grooves, a viscosity that makes the material easy to shape, and a low material cost.
A mixture of components according to the invention is par-ticularly useful for electrical insulation.
A particularly advantageous use of the invention relates to electrical insulation of electrical apparatus for outdoor use.
The objects mentioned above are achieved with a method for manufacturing a silicone rubber material according to claim 15.
DESCRIPTION OF PREFERRED EMBODIMENTS
The technical effect of the invention was verified by the following experiment.
A material was manufactured containing 100 parts by weight Wacker Powersil 318 which was mixed with 25 parts by weight of Wacker Elastosil R 490/55 and was extruded into a flat object. The mixture was hardened in a furnace at about 135 C for about 1 hour. The after-hardening was carried out for about 6 hours. At -50 C, during a DMA test, a stiffness coefficient of about 12 kPa was obtained.
The conclusion is that the material according to the in-vention had a compliance that was about 40 per cent better than a material wholly based on PDMS while at the same time the viscosity properties were maintained at an advantageous level.
In a particularly advantageous embodiment, a material was manufactured containing 100 parts by weight Wacker Powersil 318 which was mixed with 5 parts by weight of Wacker Elastosil R 490/55 and extruded into a flat object. The mixture was hardened in a furnace at about 130 C for about 1 hour. The after-hardening was carried out for about 5 hours. At -50 C, during a DMA test, a stiffness coefficient of about 13 kPa was obtained.
The conclusion is that the material according to the in-5 vention had a compliance that was about 35 per cent better than a material wholly based on PDMS while at the same time the viscosity properties were maintained at an advantageous level. The cost of the material is somewhat higher than for a material that is wholly based on PDMS but considerably 10 lower than for a material that is wholly based on a phenylated silicone rubber.
The objects mentioned above are achieved with a method for manufacturing a silicone rubber material according to claim 15.
DESCRIPTION OF PREFERRED EMBODIMENTS
The technical effect of the invention was verified by the following experiment.
A material was manufactured containing 100 parts by weight Wacker Powersil 318 which was mixed with 25 parts by weight of Wacker Elastosil R 490/55 and was extruded into a flat object. The mixture was hardened in a furnace at about 135 C for about 1 hour. The after-hardening was carried out for about 6 hours. At -50 C, during a DMA test, a stiffness coefficient of about 12 kPa was obtained.
The conclusion is that the material according to the in-vention had a compliance that was about 40 per cent better than a material wholly based on PDMS while at the same time the viscosity properties were maintained at an advantageous level.
In a particularly advantageous embodiment, a material was manufactured containing 100 parts by weight Wacker Powersil 318 which was mixed with 5 parts by weight of Wacker Elastosil R 490/55 and extruded into a flat object. The mixture was hardened in a furnace at about 130 C for about 1 hour. The after-hardening was carried out for about 5 hours. At -50 C, during a DMA test, a stiffness coefficient of about 13 kPa was obtained.
The conclusion is that the material according to the in-5 vention had a compliance that was about 35 per cent better than a material wholly based on PDMS while at the same time the viscosity properties were maintained at an advantageous level. The cost of the material is somewhat higher than for a material that is wholly based on PDMS but considerably 10 lower than for a material that is wholly based on a phenylated silicone rubber.
Claims (18)
1. A silicone rubber material for electrical insulation, wherein said material comprises a mixture of a polyalkylsi-loxane (A) and a polyarylsiloxane (B), characterized in that said mixture consists of polyarylsiloxane (B) in an amount of 3-10 parts by weight per 100 parts by weight of polyal-kylsiloxane (A).
2. A material according to any of the preceding claims, characterized in that said polyalkylsiloxane (A) is poly-dimethylsiloxane.
3. A material according to any of the preceding claims, characterized in that said polyarylsiloxane (B) is a poly-phenylsiloxane.
4. A material according to any of the preceding claims, characterized in that said material comprises a platinum catalyst for crosslinking.
5. A material according to any of the claims 1-3, character-ized in that said material comprises an organic peroxide (C).
6. A material according to claim 5, characterized in that said material consists of an organic peroxide (C) in an amount of 0.01 to 5 parts by weight per 100 parts by weight of component A.
7. A material according to any of the preceding claims, characterized in that said material comprises a filler (D).
8. A material according to claim 7, characterized in that the part by weight of said filler (D) in the material is be-tween 0.3 and 2 times as large as the part by weight of said mixture.
9. A material according to claim 7, characterized in that the part by weight of said filler in the material is between 0.5 and 1.5 times as large as the part by weight of said mixture.
10. A material according to claim 7, characterized in that the part by weight of said filler in the material is between 0.8 and 1.2 times as large as the part by weight of said mixture.
11. A material according to any of claims 7 to 10, charac-terized in that said filler consists of a fibrous filler.
12. A method for manufacturing a silicone rubber material for electrical insulation, wherein said material is characterized in that 3-10 parts by weight of polyarylsiloxane (B) and 100 parts by weight of polyalkylsiloxane (A) are mixed.
13. A method for manufacturing a material according to claim 12, characterized in that 0.3 to 2 parts by weight (D) of filler are added per part by weight of said mixture.
14. A method for manufacturing a material according to claim 12, characterized in that 0.5 to 1.5 parts by weight (D) of filler are added per part by weight of said mixture.
15. A method for manufacturing a material according to claims 12, characterized in that 0.9 to 1.2 parts by weight (D) of filler are added per part by weight of said mixture.
16. An electric insulator comprising a material according to any of claims 1-11.
17. Use of a material according to any of claims 1-11 for electrical insulation.
18. Use of a material according to any of claims 1-11 for electrical insulation for outdoor use.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE0500328 | 2005-02-09 | ||
| SE0500328-0 | 2005-02-09 | ||
| PCT/SE2006/000183 WO2006085816A1 (en) | 2005-02-09 | 2006-02-09 | Silicone rubber material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2601354A1 true CA2601354A1 (en) | 2006-08-17 |
| CA2601354C CA2601354C (en) | 2013-07-02 |
Family
ID=36793311
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2601354A Expired - Fee Related CA2601354C (en) | 2005-02-09 | 2006-02-09 | Silicone rubber material |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP1851774A4 (en) |
| CN (1) | CN101116151B (en) |
| CA (1) | CA2601354C (en) |
| RU (1) | RU2381582C2 (en) |
| WO (1) | WO2006085816A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9133340B2 (en) | 2005-07-11 | 2015-09-15 | Saint-Gobain Performance Plastics Corporation | Radiation resistant silicone formulations and medical devices formed of same |
| US7943697B2 (en) | 2005-07-11 | 2011-05-17 | Saint-Gobain Performance Plastics Corporation | Radiation resistant silicone formulations and medical devices formed of same |
| US7939014B2 (en) | 2005-07-11 | 2011-05-10 | Saint-Gobain Performance Plastics Corporation | Radiation resistant silicone formulations and medical devices formed of same |
| US20080166509A1 (en) * | 2007-01-08 | 2008-07-10 | Saint-Gobain Performance Plastics Corporation | Silicone tubing formulations and methods for making same |
| EP2195813A1 (en) * | 2007-10-03 | 2010-06-16 | ABB Research LTD | Electrical insulation system with improved electrical breakdown strength |
| EP2842992B1 (en) * | 2013-08-27 | 2017-02-08 | ContiTech Elastomer-Beschichtungen GmbH | Insulation material |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2689281B2 (en) * | 1990-07-26 | 1997-12-10 | 日本碍子株式会社 | Silicone rubber composition for insulators used outdoors |
| US5960245A (en) * | 1998-12-03 | 1999-09-28 | Eastman Kodak Company | Oil swell controlling fuser member having a silicone T-resin |
| DE60044226D1 (en) * | 1999-08-18 | 2010-06-02 | Shinetsu Chemical Co | Silicone rubber compositions, their preparation and use as high voltage insulating material |
| JP2001261963A (en) * | 2000-03-17 | 2001-09-26 | Dow Corning Toray Silicone Co Ltd | Silicone rubber composition |
| WO2002004558A1 (en) * | 2000-07-11 | 2002-01-17 | Mitsui Chemicals, Inc. | Rubber composition and use thereof |
| JP2002294074A (en) * | 2001-03-29 | 2002-10-09 | Ge Toshiba Silicones Co Ltd | Method for producing silicone rubber composition for high-voltage electrical insulator |
| JP2003128917A (en) * | 2001-10-18 | 2003-05-08 | Ge Toshiba Silicones Co Ltd | Room temperature curing polyorganosiloxane composition |
-
2006
- 2006-02-09 CA CA2601354A patent/CA2601354C/en not_active Expired - Fee Related
- 2006-02-09 EP EP06704637A patent/EP1851774A4/en not_active Withdrawn
- 2006-02-09 RU RU2007133520/09A patent/RU2381582C2/en not_active IP Right Cessation
- 2006-02-09 WO PCT/SE2006/000183 patent/WO2006085816A1/en active Application Filing
- 2006-02-09 CN CN2006800042722A patent/CN101116151B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN101116151A (en) | 2008-01-30 |
| CA2601354C (en) | 2013-07-02 |
| WO2006085816A1 (en) | 2006-08-17 |
| RU2381582C2 (en) | 2010-02-10 |
| RU2007133520A (en) | 2009-03-20 |
| EP1851774A1 (en) | 2007-11-07 |
| EP1851774A4 (en) | 2010-07-14 |
| CN101116151B (en) | 2010-09-08 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20190211 |