KR100694556B1 - Heat-vulcanizable polyorganosiloxane compositions useful in particular for making electric wires or cables - Google Patents

Abstract

The present invention is conventional in the field of a) at least one polyorganosiloxane polymer, b) at least one reinforcing filler, c) organic peroxide, d) mica, e) zinc oxide, f) optionally, thermally vulcanizable polyorganosiloxane compositions. At least one coadditive, g) platinum, platinum compound and / or platinum complex; h) titanium oxide, i) one or more packing fillers i) and j) optionally into silicone elastomers that are particularly useful for making highly flame retardant wires or electrical cables that meet current standard specifications, including species belonging to the group of wollastonite. The present invention relates to a thermally vulcanizable polyorganosiloxane composition. The composition is characterized in that the packing filler i) consists of aluminum hydroxide Al (OH) ₃ powder surface treated with an organosiloxane oligomer organosiloxane oligomer and / or an organoalkoxysilane having an alkoxy and / or OH radical.

Description

Thermally Vulcanizable Polyorganosiloxane Compositions Very Useful for Manufacturing Wires and Electrical Cables {HEAT-VULCANIZABLE POLYORGANOSILOXANE COMPOSITIONS USEFUL IN PARTICULAR FOR MAKING ELECTRIC WIRES OR CABLES}

The present invention relates to a polyorganosiloxane composition which is vulcanizable, produced from silicone elastomers, ie generally at a material temperature of from 100 ° C. to 200 ° C. and if necessary at a material temperature of up to 250 ° C. The present invention relates to the use of such compositions for the production of primary insulation or envelopes introduced into structures of wires or electrical cables that are protected from fire. The present invention relates to wires or electrical cables which are protected from fire produced by the use of the composition.

The term "wire or cable protected from fire" is understood to define a wire or electric cable which must ensure a high quality aspect, at least in terms of ash coagulation or opacity of the smoke. The characteristics that must be indicated by wires or electrical cables protected from fire are legally regulated in many countries and more stringent standards have been set.

In France, for example, an important criterion for the testing of aspects of fire from electrical cables that must be met is NF C 32-070 CR1, which relates to the operating life of cables that are burning under established conditions. Flame retardancy must take into account the creation of ash which must exhibit a certain cohesive force that allows it to maintain sufficient insulation for the operation of the cable. In this test, each cable sample was placed in a metal tube and then placed in a furnace at a temperature reaching 920 ° C. for 50 minutes and held at this temperature for 15 minutes; During this test a sample of the cable was treated with a regular impact (by impact bar striking on a metal tube with 2 impacts per minute); The test is considered to pass if the indicator lamps connected to the cable supplied with normal voltage are not switched off at the end of the test period (ie at the end of 65 minutes).

Another important standard for aspect testing for fires that must be met is the International Standards CEI 61 034, Parts 1 and 2 (CEI is an abbreviation for the International Electrotechnical Commission), which applies to electrical cables burning under the conditions By means of measuring the opacity of the smoke emitted. These tests measure the light transmittance in a small room of 27 m3 that has been clouded by the resulting flame, allowing the cable to burn under the operation of an alcohol flame installed under the set conditions. This standard is met when a light transmittance of 60% or more is obtained.

The above mentioned standard specification cannot be met for wires or electrical cables in which one or more primary insulations are studied, especially for the non-communication of fire. Indeed, according to the prior art, it is noted that the silicone elastomer-based primary insulating material obtained by thermal vulcanization reaction of a suitable polyorganosiloxane composition satisfies the flame non-electric wave test. When the silicone elastomer is burned, it is converted into an insulating brittle material with a certain cohesive force, which emits white smoke generated from spontaneous combustion of volatile residues produced by decomposition of the elastomer. However, to date, similar compositions have been proposed that are not fully satisfactory, and still require improvements in obtaining more cohesive ash, reducing the opacity of the smoke and thus reducing the intervention time of trained crews to fight fires and disasters. In order to shorten, the operation time of the cable in the fire was longer and the emission of white flames was greatly reduced.

Electrical cables according to the prior art consist of one or more single conductors (generally comprising Cu or Al), one of each of which being a primary insulation or envelope made from one or more concentric layers comprising a silicone elastomer. Protected. Around such envelope (s) one or more reinforcing members and / or one or more filling members made of glass fibers and / or inorganic fibers may be considered. Thus, it is treated with an outer sheath that may include one or more sheaths. In the case of electrical cables to a plurality of single conductors, the filling member and / or reinforcing member, which can be arranged around the single conductor (each provided with primary insulation), comprises an envelope common throughout the single conductor. Although the silicone elastomers introduced into the structure of the cable are primarily constituents of the primary insulation, this is in the filling member and / or in the reinforcing member if necessary (which constitutes a common envelope for cables to many single conductors) and / or It can be present in various proportions in the outer coating.

The number of silicon elastomeric concentric layers constituting the primary insulation or envelope from each conductor, and the wall thickness of each layer, depends primarily on the requirements added to the maintenance of work as defined in the above-mentioned standard specifications. In general, a similar operation can be obtained by using one or two layers each having a thickness of at least 0.5 mm, preferably at least 0.8 mm.

It is an object of the present invention to thermally vulcanize into silicone elastomers which can give lines and electrical cables a characteristic aspect for very high quality flames by performing at least the following improvements when already used for the formation of primary insulation. To develop a sexual polyorganosiloxane composition:

For all compositions according to the present invention, ashes capable of meeting the rule NFC 32-070 CR1 under 500 volts with an extension of at least 25% of the operating time of the wire or electrical cable to the 65 minute limit required by the standard. Improving cohesion;

Improvement of the ability to reduce smoke opacity, where the transmissivity by rule CEI 61 034, parts 1 and 2 can be achieved above 80%.

In addition, another object of the present invention is to provide improved properties to combustion and excellent properties in the absence of reheating, good properties in the reheated state, in particular operating in accordance with the insulation cable category of standard specification EI 2 It is intended to develop a thermally vulcanizable polyorganosiloxane composition having physical properties (particularly, SHORE A hardness, breaking strength, elongation at break, elastic modulus) after aging at 10 ° C. for 10 days.

In the prior art, in addition to polyorganosiloxane polymers that are crosslinked by peroxide-based catalysts, metal oxides and platinum are associated with specific cohesive and insulative brittle materials to prolong the operating time of the cables during combustion in the event of fire. Thermally vulcanizable polyorganosiloxane compositions to silicone elastomers with or without layered and / or molten fillers are disclosed.

In EP-A-0 467 800, the simultaneous use of ZnO (as molten state) and mica (as layer filler), optionally bonded to metal oxides and / or platinum compounds such as titanium oxide and oxide Fe ₃ O ₄ Presented. WO-A-01 / 34705 is based on parts by weight.

a) 100 parts by weight of polyorganosiloxane polymer,

b) 15 to 100 parts by weight of reinforcing fillers, such as silica fillers,

c) 0.2 to 8 parts by weight of organic peroxide,

d) 0.5 to 30 parts by weight of mica,

e) 0.2 to 10 parts by weight of zinc oxide,

f) 0 to 15 parts by weight of an auxiliary additive,

g) a component of 0.0010 to 0.02 parts by weight (that is, 10 ppm to 200 ppm), expressed as the weight of (element) metal platinum,

h) 0.5 to 10 parts by weight of titanium oxide,

i) 20-100 parts by weight of packing filler such as crystalline silica and

j) species belonging to the group of 0.5 to 10 parts by weight of wollastonite

It is described to improve the thermally vulcanizable polyorganosiloxane composition into a silicone elastomer comprising and to improve the prior art described above.

Extending the pallet of the composition proposed in the above-mentioned EP and WO documents, which are suitable for meeting the requirements of smoke opacity under rule 500 under 500 volts to correspond to all extrusion techniques of cables. It is preferable.

What constitutes the first object of the present invention is now described above in order to meet a pallet of a composition having a performance which is particularly useful in the field of the manufacture of electric wires or electrical cables, ie on the one hand with respect to the cohesiveness of ash and the opacity of smoke. Silicone elastomers that have aspects of fire that fully fulfill the described requirements (lines 11 to 17 of the third specification of the present specification) and, on the other hand, are useful for meeting a pallet of compositions having excellent properties for the silicone elastomers formed. A novel thermally vulcanizable polyorganosiloxane composition to a furnace.

More specifically, the present invention is based on parts by weight as a first object.

a) 100 parts by weight of polyorganosiloxane polymer,

b) 15 to 100 parts by weight of reinforcing filler,

c) 0.2 to 8 parts by weight of organic peroxide,

d) 0.5 to 30 parts by weight of mica,

e) 0.2 to 10 parts by weight of zinc oxide,

f) 0 to 15 parts by weight of an auxiliary additive,

g) a component of 0.0005 to 0.02 parts by weight (ie, 5 ppm to 200 ppm), expressed as the weight of (element) metal platinum,

h) 0.5 to 10 parts by weight of titanium oxide,

i) 20-100 parts by weight of packing filler and

j) species belonging to the group of 0-10 parts by weight of wollastonite

As a thermally vulcanizable polyorganosiloxane composition into a silicone elastomer comprising:

Packing filler i) is included in an aluminum hydroxide Al (OH) ₃ powder surface treated with an organosiloxane oligomer having alkoxy and / or OH radicals and / or an organosilazane and / or an organoalkoxysilane.

Organic groups are straight or branched chain alkyl radicals having 1 to 10 carbon atoms; Straight or branched chain alkenyl radicals having 2 to 6 carbon atoms and having 1 or 2 ethylenic double bonds; And / or at least one hydrocarbon radical selected from phenyl radicals;

Alkoxy groups are characterized in that they represent at least one alkoxy radical selected from straight or branched chain alkoxy radicals having 1 to 6 carbon atoms.

The applicant is

I) at least one packing filler made from the treated aluminum hydroxide Al (OH) ₃ powder,

The combination of inorganic components by the teaching of WO-A-01 / 34705 consisting of silica filler, mica, zinc oxide, platinum (or platinum compound or platinum complex), titanium oxide and optionally wollastonite, in particular the application of wires or electrical cables It has been found in the examples to yield the characteristic action of reinforcement in the final elastomer which can achieve improved ash cohesion and improved smoke opacity reduction.

The composition according to the invention comprises a) at least one polyorganosiloxane polymer comprising 0-4% by weight, preferably 0.01-3% by weight of vinyl groups. Such a) polyorganosiloxane polymers are referred to as oils when their viscosity at 25 ° C. is 50,000 to 1,000,000 mPa · s, but when their viscosity is greater than 1,000,000 mPa · s they are referred to as rubber. The polyorganosiloxane polymer in the composition according to the invention may be oil or rubber or mixtures thereof. The polyorganosiloxane polymer becomes a straight chain polymer, wherein the diorganopolysiloxane chain consists essentially of units of the formula R ₂ SiO. This chain is blocked at each end by a unit of formula R ₃ Si _0.5 and / or by a radical of formula OR ′. In these formulas,

R is the same or different and is a monovalent hydrocarbon radical, such as an alkyl radical such as methyl, ethyl, propyl, octyl, octadecyl; Aryl radicals such as phenyl, tolyl, xylyl; Aralkyl radicals such as benzyl, phenylethyl; Cycloalkyl and cycloalkenyl radicals such as cyclohexyl, cycloheptyl, cyclohexenyl radikil; Alkenyl radicals such as vinyl, allyl radicals; Alkali radicals, cyanoalkyl radicals such as cyanoethyl radicals; Halogenoalkyl radicals, halogenoalkenyl and halogenoaryl such as chloromethyl, trifluoro-3,3,3-propyl, chlorophenyl, dibromophenyl, trifluoromethylphenyl radical,

R 'represents a hydrogen atom, an alkyl radical having 1 to 4 carbon atoms, a betamethoxyethyl radical.

It is preferred that at least 60% of the R groups represent methyl radicals. Along the length of the diorganopolysiloxane chain, the presence of small amounts of units other than R ₂ SiO, such as the units of the formula RSiO _1.5 and / or SiO ₂ , is not excluded in the proportion of 2% or more. Where% is a measure of the number of units T and / or Q per 100 silicon atoms.

Specific examples of the units of formula R ₂ SiO and R ₃ SiO _0.5 and formula OR ′ include (CH ₃ ) ₂ SiO, CH ₃ (CH ₂ = CH) SiO, CH ₃ (C ₆ H ₅ ) SiO, (C ₆ H ₅ ) ₂ SiO, CH ₃ (C ₂ H ₅ ) SiO, (CH ₃ CH ₂ CH ₂ ) CH ₃ SiO, CH ₃ (n-C ₃ H ₇ ) SiO, (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 , CH ₃ (C ₆ H ₅ ) ₂ SiO _0.5 , CH ₃ (C ₆ H ₅ ) (CH ₂ = CH) SiO _0.5 , OH, -OCH ₃ , -OC ₂ H ₅ , -OnC ₃ H ₇ , -O-iso-C ₃ H ₇ , -OnC ₄ H ₉ , -OCH ₂ CH ₂ 0CH ₃ .

Such oils and rubbers are commercially available from silicone manufacturers or can be produced by operation by known techniques.

b) the reinforcing filler consists of silica, alumina or a mixture of the two. Examples of useful silicas include fillers having a fine particle size of 0.1 μm or less and characterized in that the ratio of surface area to weight is generally from about 50 m 2 per g to 300 m 2 per g. Silicas of this type are commercially available products, which are well known in the technology of making silicone rubber. Such silicas can be prepared by exothermic methods (which are known as combustion or smoke) or can be prepared by wet techniques (precipitated silica) and by organosilic compounds commonly used for their use. It may or may not be processed. The chemical properties and preparation are not critical to the present invention, but the silica must be capable of exhibiting reinforcing action in the final elastomer. Of course, various silica cutting methods can be used. For reinforcing alumina that can be used, it is advantageous to use highly dispersible alumina doped or undoped in a known manner. Of course, cuts of various aluminas can be used. Non-limiting examples of similar aluminas include Societe Baikowski's Alumina A 125, CR 125, D 65CR. The reinforcing filler used is preferably combustion silica, either alone or in the form of a mixture with alumina.

The organic peroxide constituting the c) component may be any which acts as a vulcanizing agent for the composition forming the silicone elastomer. Thus, any of the peroxides or peresters known to be used with the silicone elastomer, for example di-t-butyl peroxide, benzoyl peroxide, monochlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide , t-butyl peracetate, dicumyl peroxide, 2,5-dimethylhexane 2,5-diperbenzoate and bis (t-butylperoxy) -2,5-dimethyl-2,5-hexane and the like. In the manufacture of electric wires or electrical cables, the choice of peroxide is actually determined by the method used to cure the elastomer (vulcanization treatment). When this vulcanization method is carried out in the absence of pressure, for example by furnace and / or radiation (infrared) using hot air, the peroxide used is monochlorobenzoyl peroxide and / or 2,4-dichlorobenzoyl. Peroxides are preferred. If the vulcanization process is carried out in the presence of pressure, for example using a steam tube, the peroxide used is bis (t-butylperoxy) -2,5-dimethyl-2,5-hexane.

The mica constituting the d) component of the composition of the present invention may be of muscovite or phlogopite type, and the size of the mica particles is not very important, but uniform dispersion in the composition of the composition It should be small enough to be possible. The mica is preferably fine in the form of crushed mica or to a particle size of less than 100 μm.

The zinc oxide constituting the component e) of the composition according to the invention is a white or slightly yellowish powder.

g) the component platinum is in the form of a (element) metal or in the form of chloroplatinic acid (eg hexachloroplatinic acid H ₂ PtCl ₆ ); Complexes of platinum and vinyl organosiloxanes (eg Karstedt complexes), complexes of formula (PtCl ₂ olefins) ₂ and H (PtCl ₃ olefins), complexes of platinum chloride and cyclopropane, where olefins are ethylene, propylene , Butylene, cyclohexene or styrene.

h) Titanium oxide is a white powder.

i) The packing filler consists of surface treated aluminum hydroxide powder. The filler has a particle size greater than 0.1 μm.

Specific examples of the organoalkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, vinyltrimethoxysilane, and vinyltri (2 -Methoxyethoxy) silane, vinyltriacetoxysilane, allyltrimethoxysilane, butenyltrimethoxysilane, hexenyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, dimethyldimethoxysilane, Dimethyl diethoxysilane, diphenyldimethoxysilane, trimethylmethoxysilane, trimethylethoxysilane and the like.

Specific examples of organosilazane include hexamethyldisilazane or divinyltetramethyldisilazane.

Specific examples of oligomeric siloxanes are linear and / or crosslinked comprising units of the formula R ″ ₃ SiO _0.5 and / or R ″ ₂ SiO in the case of oligomers crosslinked with units of R ″ SiO _1.5 and / or SiO ₂ . Oligomers, where R ″ is a straight or branched alkyl radical having primarily 1 to 10 carbon atoms, a straight or branched chain having 2 to 6 carbon atoms and having 1 or 2 ethylene double bonds Alkenyl radical and / or phenyl radical, at least one of R " represents an OH radical or a straight or branched alkoxy radical having 1 to 6 carbon atoms.

i) The packing filler is preferably aluminum trihydroxide treated with an organoalkoxysilane.

The composition according to the invention comprises, as an optional component, at least one inorganic species belonging to the group of j) wollastonite. The group of wollastonite is calcium metasilicate (CaSi0 ₃ ) or wollastonite; Metasilicate mixtures of calcium and sodium (NaCa ₂ HSi ₃ O ₉ ) or pectolites; And inorganic species such as calcium and manganese metasilicate mixtures [CaMn (SiO ₃ ) ₂ ] or bustamite. Of course, mixtures of these various species can also be used. When using the j) component, it is preferably wollastonite. Wollastonite is represented by α-CaSiO ₃ by chemists and is typically found in nature; And pseudo wollastonite or β-CaSiO ₃ . Preference is given to using α-CaSiO ₃ . j) Inorganic species belonging to the group of wollastonite may not be surface treated or may be treated with an organosilis compound of the type described above in connection with aluminum hydroxide powder.

In addition to components a), b), c), d), e), g), h), i) and j) specifically described above, the compositions according to the invention may optionally comprise f) one or more co-additives, in particular f1 ) One or more products referred to as "semistructured"; And / or f2) at least one polysiloxane resin; And / or f3) at least one stabilizer; And / or f4) one or more colored pigments for making colored wires and cables; And / or f5) one or more boron-based compounds.

According to a preferred feature of the invention,

a) for 100 parts by weight of the polyorganosiloxane polymer

b) 20-50 parts by weight of reinforcing filler,

c) 0.5 to 6 parts by weight of organic peroxide,

d) 1 to 12 parts by weight of mica,

e) 2 to 6 parts by weight of zinc oxide,

f) 0 to 12 parts by weight of an auxiliary additive,

g) 0.0010 to 0.015 parts by weight (ie 10 ppm to 150 ppm) of components, expressed in terms of (element) metal platinum,

h) 1 to 5 parts by weight of titanium oxide,

i) 30 to 80 parts by weight of packing filler belonging to the group of treated aluminum trihydroxide and

j) species belonging to the group of 2 to 8 parts by weight of wollastonite

It relates to a thermally vulcanizable polyorganosiloxane composition into a silicone elastomer comprising a.

According to the "more preferred" feature of the invention,

a) for 100 parts by weight of the polyorganosiloxane polymer

b) 30-40 parts by weight of reinforcing filler,

c) 1 to 5 parts by weight of organic peroxide,

d) 7-12 parts by weight of mica,

e) 4 to 6 parts by weight of zinc oxide,

f) 5 to 10 parts by weight of auxiliary additives,

g) 0.002 to 0.01 parts by weight (i.e. 20 ppm to 100 ppm) of components, expressed in terms of (element) metal platinum,

h) 3 to 5 parts by weight of titanium oxide,

i) 50 to 80 parts by weight of packing filler belonging to the group of treated aluminum trihydroxide and

j) species belonging to the group of 4 to 8 parts by weight of wollastonite

It relates to a thermally vulcanizable polyorganosiloxane composition into a silicone elastomer comprising a.

According to another example where the content of the various components is expressed in weight percent based on the total weight of the composition, the "more preferred" compositions of the present invention (in each case the sum of the components should correspond to 100 weight percent).

a) 40-50% by weight of polyorganosiloxane

b) 12-20% by weight of reinforcing filler

c) 0.4-2.5 wt% of organic peroxide

d) 2.8 to 6% by weight of mica

e) 1.6 to 3% by weight of zinc oxide

f) 2 to 5 wt% of auxiliary additives

g) 0.0008 to 0.005% by weight of metal platinum

h) 1.2-2.5 wt% titanium oxide

i) 20-40 wt% packing filler

j) 1.6 to 4% by weight of the group of wollastonite

f) Returning to the co-additives, when using at least 1, more specifically [a) per 100 parts by weight of polyorganosiloxane polymer]

f1) a polydimethylsiloxane oil having a viscosity at 25 ° C. of 10 to 3,000 mPa · s and a hydroxy group blocked at each end of the chain and / or a viscosity at 25 ° C. of 10 to 1,000 mPa · s, and 0.1 to 15 parts by weight of a product, referred to as "semi-structured", consisting of poly (methylvinyl) siloxane oil blocked with a hydroxy group at each end of; And / or

- f2) is substantially R "_'3 SiO _0.5 and units (wherein R a SiO _2"' comprises a represents a 1 halogenated optionally having a carbon atom of less than 7 hydrocarbon), ₃ R "'on the SiO ₂ The weight ratio of SiO _0.5 is from MQ resins of 0.5 / 1 to 1/2/1; substantially including HR ″ ′ ₂ SiO _0.5 and units of SiO ₂ , where R ″ ′ is as described above, with respect to SiO ₂ The weight ratio of HR ″ ′ ₂ SiO _0.5 is 0.1 to 5 parts by weight of polysiloxane resin represented by M′Q resin of 0.5 / 1 to 10/1; And / or

f3) metal salts of organic acids, such as salts of iron or cerium, such as octoates of iron or cerium, with a proportion of from 0.01 to 1 part by weight; Cerium oxide, cerium hydroxide, iron oxide (the ratio thereof is 0.1-4 weight part); 0.01-4 parts by weight of a stabilizer such as oxide CaO, oxide MgO (the ratio thereof is 0.01-0.4 parts by weight); And / or

f4) 0.01 to 5 parts by weight of the colored pigment; And / or

f5) boric acid and derivatives thereof, for example from 0.01 to 3 parts by weight of boron-based compounds as alkyl ester derivatives having 1 to 3 carbon atoms;

The total amount of the additive is 15 parts by weight for a general composition when using at least one additive; 12 weight percent for a "preferred" composition; Equivalent to 10% by weight for a "more preferred" composition.

In the preparation of the compositions according to the invention, the various components are initially thoroughly mixed by means of devices known in the industry of silicone elastomers to the extent of incorporation in a predetermined proportion. Initially, however, a) group of a) polyorganosiloxanes, for example b) reinforcing fillers one or more times, f1) and f2) possible additives, d) mica, e) zinc oxide, h) titanium oxide, j) wollastonite Species, g) Pt-based components, f3) possible additives, i) packing fillers belonging to the group of treated aluminum trihydroxide, and then dispersed in these mixtures in a predetermined amount of c) catalyst and f4) and f5) It is advantageous to add possible additives.

A second object of the present invention is also directed to the use of the polyorganosiloxane composition just described above for the formation of a primary insulation or envelope of a single conductor, in particular introduced into a structure of a wire or electrical cable protected from fire. will be.

A third object of the present invention relates to an electric wire or an electric cable produced by the use of the polyorganosiloxane composition according to the first object of the present invention.

Within the scope of similar applications, the deposition of the composition according to the invention around each single conductor can be carried out by conventional methods, for example by extrusion. The deposit thus obtained is crosslinked by heating to form a primary insulating material into the silicone elastomer. The heating time depends on the temperature of the material and the working time. The temperature of the material is generally about 100 ° C to 200 ° C. Multiple layers can be attached, for example, by tandem extrusion or coextrusion with a square head.

According to the examples presented below will be described the present invention in more detail.

Compositions According to the Invention (All Parts Are By Weight)

1. Manufacture

The following materials are mixed at room temperature (23 ° C.) for 2 hours in a kneading mixer with arms on the Z axis.

a) 66.61 parts by weight of polyorganosiloxane (viscosity at 25 ° C. is 20,000,000 mPa · s and is polydimethylsiloxane blocked by dimethylvinylsiloxy units comprising 120 ppm of Vi groups at each of two ends) ;

a) 33.39 parts by weight of polyorganosiloxane (poly (dimethyl) (methyl blocked at 25 ° C. with 20,000,000 mPa · s and blocked by trimethylsiloxy units comprising 720 ppm of Vi groups at each of two ends) Vinyl) siloxane);

b) 19.07 parts by weight of combustion silica [treated with D4 (octamethylcyclotetrasiloxane) and specific surface area is 200 m 2 / g];

b) 12.4 parts by weight of combustion silica (specific surface area is 150 m 2 / g);

f1) 2.86 parts by weight of polydimethylsiloxane oil, having a viscosity at 25 ° C. of 50 mPa · s and blocked by dimethylhydroxysiloxy units at two respective ends;

f1) 1.91 parts by weight of poly (methylvinyl) siloxane oil (blocked by methylvinylhydroxysiloxy units comprising 9% by weight of OH at each of two ends and 3% by weight of Vi group in the chain, 25 The viscosity at 25 ° C. is 25 mPa · s);

d) 9.61 parts by weight of muscobite mica;

e) 4.89 parts by weight of zinc oxide;

h) 3.46 parts by weight of combustion TiO ₂ ;

j) 6.62 parts by weight of wollastonite α-CaSi0 ₃ (treated with methylalkoxysilane sold as Wollastonite Tremin 283-800 TST by Societe Quartz Warke);

g) 0.003 parts by weight of metal platinum [in the form of a solution of 10% by weight of a platinum complex (Karstedt complex) coordinated by divinyltetramethyldisiloxane in divinyltetramethyldisiloxane];

f3) 0.28 parts by weight of calcium oxide;

f3) 0.39 parts by weight of iron octanoate;

f3) 2.76 parts by weight of Ce (OH) ₄ ; And

i) 66.17 parts by weight of filler, which is aluminum trihydroxide treated with 1% by weight of vinyltri (2-methoxyethoxy) silane sold under the tradename Aluminum Hydroxide AP 40 VS1 by Societe Navaltech.

The mixture obtained above was operated on a mixer with two cylinders, and c) an organic peroxide constituting the catalyst was added.

2. Characteristics of the composition

(i) The homogeneous mass fraction obtained in the mixer was used to measure the physical properties of the silicone elastomer resulting from thermal vulcanization of the polyorganosiloxane composition. To this end, in fact, catalyzed by 0.6 parts by weight of bis (t-butylperoxy) -2,5-dimethyl-2,5-hexane per 100 parts by weight of the homogeneous mass fraction retained for this purpose, a 2 mm thick plate The solution was vulcanized at 170 ° C. for 10 minutes while working in a suitable mold to allow production. Thus, a plate in the non-reheated state (NR) was obtained. Fractions of the plates were treated with 200 days of aging or heating (R). The whole plate of standardized sample was then taken and its properties measured as follows:

Shore hardness A (DSA) according to DIN standard 53505,

-Breaking strength (R / R) according to standard AFNOR NF T 46002 (unit: MPa),

Elongation at break (A / R) according to the above standard (unit:%),

Modulus of elasticity (ME) in 100% according to the above standard (unit: MPa).

Another fraction of the homogeneous mass obtained in the (2i) mixer was catalyzed with 1.25 parts by weight of 2,4-dichlorobenzoyl peroxide per 100 parts by weight of homogeneous mass. Thereafter, it was cut into bands and fed to an extruder for carrying out the manufacture of the electric cable. The manufacture of the cable is carried out for 46 seconds on a single conductor coated with the homogenous polyorganosiloxane composition described above at a temperature of 250 ° C. (with a material temperature of about 130 ° C. to 140 ° C.) in a furnace using hot air. To produce a 3 mm diameter cable comprising a single conductor of 1.38 mm diameter copper, mounted around a primary envelope or insulation made of 0.81 mm thick silicone elastomer, obtained by treatment in a vulcanization reaction. It consists of Then, a cable of standardized samples was taken and its properties measured as follows:

Cohesion of ash under 500 volts by standard specification NF C 32-070 CR1 using stainless steel metal tubes,

-Opacity of smoke according to standard CEI 61 034, part 1 (% light transmittance).

The results obtained are shown in Table 1 below.

Yes NR Properties DSA 7.1 R / R (MPa) 6.6 A / R (%) 230 ME 100 (MPa) 3.3 R property DSA 76 R / R (MPa) 6 A / R (%) 170 ME 100 (MPa) 4.1 Cohesion of ash under 500 volts (hours, minutes) Test 1 69 Test 2 79 Test 3 73 Test 4 82 Test 5 > 95 Test 6 57 Test 7 > 95 Test 8 > 95 Test 9 > 95 Test 10 > 95 Average value (minute) 84 Bilan 9/10 Pass rate 90% Opacity of smoke (light transmittance) 86%

According to the present invention, (i) the operating time of a wire or electric cable is extended by 29% for a 65 minute limit required by standard NF C 32-070 CR1 to provide a standard NF C 32-070 CR1 under 500 volts. And (ii) the light transmittance was improved by 43% for the 60% minute limit required by standard CEI 61 034, part 1 to meet standard standard CEI 61 034, part 1.

Claims (10)

On the basis of parts by weight a) 100 parts by weight of polyorganosiloxane polymer, b) 15 to 100 parts by weight of reinforcing filler, c) 0.2 to 8 parts by weight of organic peroxide, d) 0.5 to 30 parts by weight of mica, e) 0.2 to 10 parts by weight of zinc oxide, f) 0 to 15 parts by weight of an auxiliary additive, g) a component of 0.0005 to 0.02 parts by weight (ie, 5 ppm to 200 ppm), expressed as the weight of (element) metal platinum, h) 0.5 to 10 parts by weight of titanium oxide, i) 20-100 parts by weight of packing filler and j) one or more species belonging to the group of 0-10 parts by weight of wollastonite As a thermally vulcanizable polyorganosiloxane composition into a silicone elastomer comprising: The composition consists of an aluminum hydroxide Al (OH) ₃ powder in which the packing filler i) is surface treated with an organosiloxane oligomer having an alkoxy, OH radical, or both, organosilazane, organoalkoxysilane, or a combination thereof. Done, where Organic groups are straight or branched chain alkyl radicals having 1 to 10 carbon atoms; Straight or branched chain alkenyl radicals having 2 to 6 carbon atoms and having 1 or 2 ethylenic double bonds; One or more hydrocarbon radicals selected from phenyl radicals, or combinations thereof; Thermally vulcanizable polyorganosiloxane composition, characterized in that the alkoxy group represents at least one alkoxy radical selected from straight or branched chain alkoxy radicals having 1 to 6 carbon atoms. The method of claim 1, a) for 100 parts by weight of the polyorganosiloxane polymer b) 20-50 parts by weight of reinforcing filler, c) 0.5 to 6 parts by weight of organic peroxide, d) 1 to 12 parts by weight of mica, e) 2 to 6 parts by weight of zinc oxide, f) 0 to 12 parts by weight of an auxiliary additive, g) (element) a component of 0.0010 to 0.015 parts by weight (ie, 10 ppm to 150 ppm), expressed as the weight of metal platinum, h) 1 to 5 parts by weight of titanium oxide, i) 30 to 80 parts by weight of packing filler belonging to the group of treated aluminum trihydroxide and j) A thermo vulcanizable polyorganosiloxane composition comprising one or more species belonging to the group of 2 to 8 parts by weight of wollastonite. A component according to claim 1 or 2, characterized in that component a) consists of at least one polyorganosiloxane polymer having a viscosity at 25 ° C. of greater than 1 million mPa · s and containing from 0 to 4% by weight of vinyl groups. A thermally vulcanizable polyorganosiloxane composition. The thermally vulcanizable polyorganosiloxane composition according to claim 1 or 2, wherein component b) consists of silica, alumina or a mixture of two kinds thereof. The thermally vulcanizable polyorganosiloxane composition according to claim 1 or 2, wherein component i) consists of at least one aluminum trihydroxide treated with an organoalkoxysilane. 3. The composition of claim 1, wherein component j) comprises calcium metasilicate (CaSi0 ₃ ) or wollastonite in use of the composition; Metasilicate mixtures of calcium and sodium (NaCa ₂ HSi ₃ O ₉ ) or pectolites; And at least one species selected from a metasilicate mixture [CaMn (SiO ₃ ) ₂ ] or bustamite of calcium and manganese. 3. The component of claim 1, wherein the optional component f) comprises at least one product, referred to as f1) “semi-structured” in its use; f2) at least one polysiloxane resin; f3) at least one stabilizer; f4) at least one colored pigment; f5) A thermally vulcanizable polyorganosiloxane composition comprising one or more boron-based compounds, or a combination thereof. Fire, consisting of performing the deposition of the composition according to claim 1 around each single conductor and then crosslinking it with a silicone elastomer by heating providing a material temperature of from 100 ° C to 200 ° C. A method of using the composition according to claim 1 or 2 for forming at least one single conductor primary insulation or envelope which is introduced into the structure of a wire or an electrical cable protected from. At least one monoconductor formed by carrying out the attachment of the composition according to claim 1 or 2 around each monoconductor and then crosslinking it with the silicone elastomer by heating providing a material temperature of 100 ° C to 200 ° C. Wires or electrical cables protected from fire, manufactured using car insulation or envelopes. 10. The method according to claim 9, wherein (1) the light transmittance according to Rule CEI 61 034, part 1 provides smoke opacity to achieve at least 80%; (2) Wire or electricity characterized by meeting rule NFC 32-070 CR1 under 500 volts by extending the operating time of the wire or electrical cable by 25% or more for the 65-minute limit required by rule NFC 32-070 CR1. cable.