FR2604180A1 - ORGANOPOLYSILOXANE COMPOSITION - Google Patents

Abstract

THE PRESENT INVENTION CONCERNS A COMPOSITION OF ORGANOPOLYSILOXANE COMPRISING: A: 100 PARTS BY WEIGHT OF A VINYL POLYORGANOSILOXANE, COMPRISING: I FROM 70 TO 98 PARTS BY WEIGHT OF A LINEAR ORGANOPOLYSILOXANE WITH VINYL TERMINATION OF HIGH VISCOSITY; II FROM 1 TO 15 PARTS BY WEIGHT OF A LINEAR ORGANOPOLYSILOXANE OF LOW VISCOSITY, WITH AT LEAST ONE TERMINAL VINYL GROUP PER MOLECULE, AND III FROM 1 TO 15 PARTS BY WEIGHT OF A CHAIN ORGANOPOLYSILOXANE CONTAINING VINYL GROUPS; B: ABOUT 5 TO ABOUT 70 PARTS BY WEIGHT OF A LOAD OR COMBINATION OF LOADS; C: ABOUT 0.1 TO 50 PARTS PER MILLION BASED ON THE TOTAL ORGANOPOLYSILOXANE COMPOSITION OF A PLATINUM CATALYST; AND D: OF ABOUT 0.5 TO 25 PARTS BY WEIGHT OF A CONSTITUENT CHOSEN FROM HYDROGENIC SILANES AND HYDROGENIC ORGANOPOLYSILOXANES.

Description

The present invention relates to organopolysiloxane compositions

  Transparent high-strength films for liquid injection molding. The present invention relates more particularly to such compositions which are cured via reactions involving SiH groups with an adjusted mixture.

of olefinic organopolysiloxanes.

  Molten injection molding organopolysiloxane compositions (LIM) are known and used. A problem with these compositions is that the hardness, tensile strength, elongation and tear resistance are dependent on each other and the viscosity of the uncured liquid, so that it is difficult to improve a property without adversely affecting another. In particular, it is desirable to improve the hardness and tear resistance without reducing the others.

properties.

  U.S. Patent Nos. 3,884,866 and 3,957,713 to Jeram describe high strength, addition-hardened compositions suitable for low pressure liquid injection molding. These compositions comprise a first component containing a vinyl terminated high viscosity organopolysiloxane, a low viscosity vinyl organopolysiloxane, a filler and a platinum catalyst, which is cured by mixing with a second component containing a hydrogenated silicone composition. This composition has a low hardness index (a Shore A hardness index of 20 to 35) and it is furthermore difficult to increase the hardness without adversely affecting the other properties. U.S. Patent No. 4,162,243 to Lee et al. Discloses Jeram-like compositions which contain the most distinguishing features of fumed silica treated with hexamethyldisilazane and tetramethyldivinyldisilazane. The compositions of Lee et al. are cured elastomers having a high hardness with good retention of other properties, including strength, elongation and tear resistance in addition

  to have a low viscosity in the uncured state.

  Sweet's US-A-4,427,801 is an extension of that of Lee et al. by the incorporation of an MMViQ type resin in addition to the fumed silica containing vinyl groups. This gives elastomers having even higher hardness and tear strength, but with the disadvantage of more compressive deformation.

  high and weaker Bashore resilience.

  It is therefore an object of the present invention to provide a liquid injection molding organopolysiloxane composition having high hardness and high tear strength without thereby having adverse effects on

other physical properties.

  Another object of the present invention is to provide such liquid injection molding organopolysiloxane compositions which further have good shelf life and stability stability.

good demoldability.

  These and other goals will appear to the man of

  art from reading the description, examples and

demands.

  The present invention relates to a LIM type organopolysiloxane composition, combining low viscosity, high strength and good elongation with exceptionally good hardness and tear resistance, comprising: (A) 100 parts by weight of a vinyl polyorganosiloxane composition comprising: (1) from 70 to 98 parts by weight of a high viscosity vinyl terminated linear organopolysiloxane having not more than 25 mol% of phenyl groups and having a viscosity of about 2 Pa.s at about 1000 Pa.s at 25 ° C, (2) from 1 to 15 parts by weight of a linear low viscosity organopolysiloxane having at least one terminal vinyl group per molecule, having a vinyl group content which may vary from 0.01 moles percent vinyl groups to 60 moles percent vinyl groups, having a viscosity ranging from about 0.05 Pa.s to about 5 Pa.s at 25 C and not more than 25% by weight. mole of phenyl groups, and (3) from 1 to 15 parts by weight of a vinyl chain-containing organopolysiloxane having from about 0.1 to about 25 mole% vinyl groups having a viscosity ranging from about 0.05 Pa.s about 100 Pa.s at 25 C and not more than about 25 mol% phenyl groups; (B) from about 5 to about 70 parts by weight of a filler or a combination of filler; (C) from about 0.1 to 50 parts per million

  the total composition of the organi-

  polysiloxane of a platinum catalyst; (D) from about 0.1 to 10 parts by weight of an SiH group component selected from hydrogenated silanes and hydrogenated organopolysiloxanes; and (E) optionally, from about 0.1 to 6.0 parts by weight of a hydroxyl-containing fluid organopolysiloxane having a viscosity of about 0.005 Pa.s

about 0.1 Pa.s at 25 C.

  This composition can be either cured to an elastomer at room temperature for 16 hours or it can be cured at elevated temperatures, such as, for example, at 200 ° C. for 10 seconds. In a preferred embodiment, the above-mentioned composition is a two-component composition in which the first component contains at least all of component (C), and wherein the second component contains at least

the entire constituent (D).

  The high viscosity vinyl terminated linear organopolysiloxane of the present invention does not have more than 25 mol% phenyl groups and has a viscosity of about 2 Pa.s to about 1000 Pa.s at 25 ° C., preferably from about 10 Pa.s to about 500 Pa.s at 25 C. These high viscosity organopolysiloxanes can be represented by the general formula: tR R

* I

  (1) Vi - Si i OS os Vi R x R wherein Vi represents a vinyl group, R is selected from monovalent hydrocarbon groups and halogenated monovalent hydrocarbon groups having up to about 20 carbon atoms, and x may vary from from about 100 to about 10,000, preferably from about 500 to 2,000. Suitable high viscosity organopolysiloxanes are described in US Pat.

  U.S. Patent No. 3,884,866, incorporated herein by reference.

  The linear low viscosity organopolysiloxane A (2) of the present invention has at least one terminal vinyl group per molecule, it has a vinyl group content which may vary from about 0.01 mole of vinyl groups per hundred to about 60 moles of vinyl groups per cent, preferably 0.05 to 10 moles of vinyl groups per cent; it has a viscosity which ranges from about 0.05 Pa.s to about 5 Pa.s at 25 ° C, preferably from about 0.05 to about 1 Pa.s at 25 ° C; and it does not comprise more than about 25 mol% of phenyl groups. These low viscosity organopolysiloxanes may be represented by the general formula:

R R R

  (2) wherein R is as defined above, R1 is identical to R except that at least one R1 group may be a vinyl group; and y may vary from about 1 to about 750. Suitable low viscosity organopolysiloxanes are described in US-A-3,884,866, which is incorporated herein by reference.

given here for reference.

  The vinyl chain-containing organopolysiloxane A (3) of the present invention is

  determining to obtain the expected properties.

  Suitable vinyl chain-containing organopolysiloxanes have from about 0.1 to about 25 mole percent of vinyl groups and preferably from about 0.2 to about 5 mole percent of vinyl groups, they have a varying viscosity. from about 0.05 to about 100 Pa.s at 25 C, preferably from about 0.1 to about 10 Pa.s at 25 C, and they contain not more than about 25 mol% of phenyl groups . These organopolysiloxanes can be characterized as being copolymers of siloxane units (I) of formula: (3) Ra (3) Ra eb SiO (4-ab) / 2 in which R is as defined above, R2 represents a group olefinic hydrocarbon bonded to the silicon atom by a C-Si bond, and it generally contains from 1 to 20 carbon atoms aliphatic straight or branched chain, and preferably from 1 to 12 carbon atoms bonded through of multiple bonds, aa has a value ranging from 0 to 2 inclusive, and the sum of a and b ranges from 0.8 to 3.0 inclusive; and organopolysiloxane units (2) of the formula: (4) Rc Si 0 (4-c) / 2 wherein R is as defined above and c is from 0.8 to 2.5 inclusive. R2 may be for example an allyl, methallyl, butenyl, pentenyl, ethenyl and the like, but is preferably a vinyl group. The copolymer generally contains from 0.5 to 99.5 mol% of units of formula 3 and from 0.5 to 99.5 mol% of units of formula 4. The preparation of these copolymers is well known in the art . They are described in US-A-3,344,111 to Chalk and US-A-3,436,366 to

  Modic which are given here for reference.

  The preferred chain organopolysiloxanes having vinyl groups are linear and correspond to the general formula:

R R R R

  (5) Vi - If si5 0 i osi Vi R R d R R

  wherein R and R2 are as defined above

  above, and d and e are positive integers so that the polymer contains up to about 20 mol% of R2 groups. R2 is preferably vinyl, the polymer contains from about 0.05 to 10 mole% of R2 groups, and the viscosity varies.

  from about 0.3 to about 1 Pa.s at 25 ° C.

  As mentioned above, the R group is selected from monovalent hydrocarbon groups and halogenated monovalent hydrocarbon groups having up to about 20 carbon atoms, i.e. groups that usually form.

  substituent groups on organopolysiloxanes.

  The R group may thus be selected from monocyclic and bicyclic aryl groups, such as phenyl, tolyl, xylyl, naphthyl, etc .; halogenated monocyclic and bicyclic aryl groups, such as chlorophenyl, chloronaphthyl, etc .; (monocyclic aryl) lower alkyl groups having from 1 to 8 carbon atoms per alkyl group, such as benzyl, phenyl, etc .; lower alkyl groups having 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, etc .; lower alkenyl groups having 2 to 8 carbon atoms, such as vinyl, allyl and 1-propenyl; halogenated lower alkyl groups having from 1 to 8 carbon atoms, such as chloropropyl and trifluoropropyl groups; and cycloalkyl groups, such as cyclobutyl, cyclopentyl and cyclohexyl. Although the R group may represent any of the groups mentioned above, it will be apparent to those skilled in the art that each R group can not be a high molecular weight group and that the R group can not be selected so as to adversely affect the reactions with the vinyl groups. The group R is preferably a lower alkyl group of 1 to 8 carbon atoms, such as, for example, a methyl, ethyl, phenyl and trifluoropropyl group. The R groups in particular comprise at least about 70% by number of methyl groups. The aspect of the present invention according to which it differs from the prior art SiH group-containing olefin silicone rubber compositions is the presence in the

260418O

  composition of three vinyl organopolysiloxanes.

  As mentioned above, these vinyl organopolysiloxanes include organopolysiloxane of high viscosity A (1); organopolysiloxane of low viscosity A (2); and the organopolysiloxane A (3) chain containing vinyl groups. For 100 parts by weight of vinyl organopolysiloxane there should be about 70 to 98 parts by weight of compound A (1), about 1 to 15 parts by weight of compound A (2), and about 1 & 15 parts by weight of compound A (3). It should preferably be from about 80 to 95 parts by weight of the compound A (1), from about 3 to 10 parts by weight of the compound A (2), and from about 3 to 10 parts by weight of the compound A (3). Such a mixture of vinyl organopolysiloxanes gives a cured composition having exceptionally good hardness and tear resistance in combination with high strength and elongation. The cured composition has a tensile strength of about 6.895.106 Pa or greater, an elongation of 600% or more, a tear strength of 35.7 kg / cm or more, and a hardness of

Shore A from 35 to 40 or more.

  The SiH (D) component of the present invention serves as a crosslinking agent and may be selected from hydrogenated silanes and hydrogenated organopolysiloxanes. It preferably comprises a hydrogenated organopolysiloxane. The hydrogenated organopolysiloxanes of the present invention can therefore be characterized as being copolymers containing, per molecule, at least one unit of formula: (6) Rf Hg SiO (4-fh) / 2 The remaining siloxane units in the organopolysiloxane corresponding to the Formula 4 mentioned above, with the exception of the important fact that the R group in Formula 4 and Group R above must be saturated; f has a value ranging from 0 to 2 inclusive; and the sum of f and g ranges from 0.8 to 3.0. The viscosity of the hydrogenated organopolysiloxane should be from about 0.005 to about 1, and preferably from about 0.005 to about 0.1 Pa.s at 1 ° C.

  Also included in the organopoly-

  hydrogenated siloxane described above, the MQ type resins comprising, for example, H (R) 2 SiO1 / 2 and SiO2 units. Resins of MDQ, MTQ, MDT type, etc. substituted with hydrogen atoms, are also included. This copolymer generally contains from 0.5 to 99.5 mol% of the units of formula 6 and from

  0.5 to 99.5 mol% of the units of formula 4.

  The preferred hydrogenated organopolysiloxane is a linear organopolysiloxane polymer of formula:

R X R R R

3 3

  Wherein R is as defined above except for the unsaturated compounds, R3 is the same as R except for the unsaturated compounds and with the addition of R atoms. hydrogen, h varies from 1 to 1000, and i varies from 5 to 200. h varies preferably

  from 10 to 500 and i varies from 5 to 200.

  The hydrogenated organopolysiloxane (D) is used at a concentration of from about 0.5 to 25 parts by weight per 100 parts by weight of component (A), and preferably at a concentration of about 0.5 to 10 parts by weight. parts by weight per 100 parts by weight of component (A). It is desirable that there be in the SiH group product at least one hydrogen atom for each vinyl group in the compound (A), and preferably about 1.5 to about 2.5

  hydrogen atoms for each vinyl group.

  Many types of platinum catalysts are known for this SiH 2 olefin addition reaction and these platinum catalysts can also be used for the reaction in the present case. Preferred platinum catalysts, particularly where optical clarity is desired, include platinum-based catalysts which are soluble in the present reaction mixture. The platinum-based compound can be chosen from those of formula (PtCl 2 Olefin) 2 and H (PtCl 3 Olefin) as is

  described in U.S. Patent No. 3,159,601 to Ashby.

  The olefin illustrated in the two preceding formulas may be almost of any type of olefin, but it is preferably an alkenylene containing from 2 to 8 carbon atoms, a cycloalkenylene comprising from 5 to 7 carbon atoms, or styrene. Typical olefins that can be used in the above formulas include ethylene, propylene, the various isomers of butylene, octylene, cyclopentene, cyclohexene, cycloheptene, and the like. Another platinum-containing material that is useful in the composition of the present invention is the cyclopropane and platinum chloride complex described in US-A-3,159.

662 from Ashby.

  The platinum-containing material may further be a complex formed with chloroplatinic acid and up to 2 moles per gram of platinum of a compound selected from alcohols, ethers, aldehydes and mixtures thereof such as is described in US-A-3,220,972

from Lamoreaux.

  All patents and patent applications

  mentioned in this description, are

  incorporated in this application for reference. The platinum compound preferred for use not only as a platinum catalyst but also as an ignition retardation additive is that disclosed in French Patent No. 48,775 to Karstedt. In general, this type of platinum complex is formed by reacting chloroplatinic acid containing 4 moles of water of hydration with tetravinylcyclotetrasiloxane in the presence of

  sodium bicarbonate in an ethanol solution.

  Those skilled in the art can easily determine the effective amount of platinum catalyst. In general, an effective amount is about 0.1 to 50 parts per million compared to

  all of the organopolysiloxane composition.

  In order to obtain high tensile strength in the compositions of the present invention, and particularly when the compositions are in the form of coatings or thin films, it is desirable to incorporate a filler (B) into the composition . Examples of the many fillers that can be used include titanium dioxide, lithopone, zinc oxide, zirconium silicate, silica airgel, iron oxide, diatomaceous earth, carbonate Calcium, fumed silica, silica treated with silazane, precipitated silica, glass fibers, magnesium oxide, chromic oxide, zirconium oxide, oxide aluminum, alpha-quartz, calcined clay, asbestos, carbon, graphite, cork, cotton, synthetic fibers, etc. Preferred fillers which are to be used in the composition of the present invention include either fumed silica or precipitated silica which has undergone a surface treatment. In a surface treatment process, the fumed silica or precipitated silica is exposed to cyclic organopolysiloxanes under heat and pressure. This surface treatment method is described in US Pat. No. 2,938,009 to Lucas, incorporated herein by reference. Another process for treating the surface of the charges is a process in which the silica is exposed to siloxanes or

  silanes in the presence of an amine compound.

  This process is described in US-A-3,024,126

  mentioned here for reference.

  The preferred method of surface treatment of the feeds employs surface treating agents based on methylsilane or silazane. The fumed or precipitated silica fillers, surface-treated with methylsilane or silazane, flow freely and do not undesirably increase the low viscosity of the uncured composition. In contrast, silazane-treated silica fillers simultaneously increase the physical properties of the cured elastomer, particularly the tear strength of the cured elastomer. The best properties are obtained when the silazane treatment is carried out in situ on the feedstock, i.e. when the filler has been mixed with component (A). The fumed silica or precipitated silica treated with a silazane is described in US-A-3,635,743 to Smith and US-A-3,847,848 to Beers, which are mentioned herein at

reference title.

  The filler (B) is generally used in a concentration of 5 to 70 parts, preferably 15 to 50 parts filler per 100 parts by weight of component (A). The preferred filler is silazane-treated fumed silica or silazane-treated fumed silica mixtures and silazane-treated precipitated silica. This latter mixture is particularly preferred. These silica mixtures should have a weight ratio of fumed silica to precipitated silica of from about 1: 1 to about 1: 1, and preferably about 10: 1 to about 1: 1.

about 5/1.

  Hydroxylated organopolysiloxane (E) can be added to extend the shelf life

  of the LIM type organopolysiloxane composition.

  When a silazane-treated precipitated silica filler is present in the composition, the hydroxyl-containing fluid organopolysiloxane must be added in combination with the precipitated silica filler to obtain a prolonged shelf life and demoldability. A suitable hydroxylated fluid organopolysiloxane has a viscosity of about 0.5 to about 1 Pa.s at 25 ° C, and preferably about 0.2 to about 0.5 Pa.s. These fluids may be represented by the formula: ## STR2 ## in which R is as defined above, may vary from 0 to 3, preferably from 0, 5 to 2.0, k is from 0.005 to about 2, and the sum of j and k varies from 0.8 to 3. The hydroxyl-containing organopolysiloxane is hydroxyl-terminated linear as

substituent group.

  To obtain mold release properties using a combination of silazane-treated precipitated silica and component (E), or to obtain an extended shelf life by adding component (E) alone, component (B) must comprise at least about 2 parts by weight of silazane-treated precipitated silica per 100 parts by weight of component (A) and there must be from about 1 to about 5 parts by weight of component (E) per 100 parts by weight of

constituent (A).

  The ingredients present in component (C) of component 1 are packaged separately from the ingredients present in component (D) of component 2 until curing. Constituents (A), (B), (E) and additives can be distributed between each component or be added entirely to a component. Premature reactions are thus prevented during storage and transport. When it is desired to form the cured silicone rubber composition, the two components are mixed together and the composition is allowed to cure for 16 hours at room temperature or higher temperatures to obtain more curing times.

short.

  Components 1 and 2 may be directly injection molded or dissolved in solvents for application as a film or coating. For injection molding, the mixing barrel and the injection chamber must be cold to prevent premature hardening. Molding temperature

  generally varies from about 65.5 C to about 260 C.

  Solvents for coating films or coatings include organic solvents which are usually used in the prior art

  for SiH group olefin adducting reagents.

  These solvents include, for example, hexane, heptane, pentane, octane, cyclohexane, toluene, xylene, acetone, etc. Of course, other ingredients can be added for various applications. Pigments, thixotropic agents, heat stabilizers, and the like may be added according to the teachings of the art. In particular, it is desirable to add inhibitors such as maleates in order to obtain a reasonable application time of the catalyzed material. Suitable inhibitors are described in US-A-4,256,870 mentioned herein

& title of reference.

Examples

  Products (A) High viscosity vinyl-terminated organopolysiloxane HVO1: Dimethylvinyl-terminated polydimethylsiloxane polymer having a

viscosity of 80 Pa.s at 25 C.

  HV02: dimethylvinyl terminated polydimethylsiloxane polymer having a

viscosity of 4 Pa.s at 25 ° C.

  (B) Low viscosity vinyl organopolysiloxane LVO: trimethylsilyl / dimethylvinyl terminated polydimethylsiloxane polymer having a viscosity of 0.5 Pa.s at

25'C.

  (C) Organopolysiloxane & chain having VCO1 vinyl groups: dimethylvinyl-terminated poly (dimethyl-methylvinyl) siloxane polymer having a viscosity of 0.5 Pa.s at 250.degree. C. and having about 1.65% by weight of

vinyl groups.

  VCO 2: trimethylsilyl-terminated poly (dimethyl-methyl-vinyl) siloxane polymer having a viscosity of 2000 Pa.s at 25 ° C. and having 13.5 mol% of groups

MeVi siloxy.

  (D) Silica filler Silica fumed surface treated with a cyclic or methyl tetramer Precipitated silica treated with hexamethyl disilazane (E) Catalyst Catalyst with platinum Karstedt dissolved in

methylvinyl tetramer.

  Lamoreau platinum catalyst dispersed in LVO1 as a vehicle & a concentration of

% in weight.

  (F) SiH RHC Crosslinking Agent: Hydride resinous crosslinking agent represented by the formula MHQ having a viscosity of 0.2 Pa.s at 25 ° C and having about 0.9 wt% of carbon atoms. hydrogen. LHC: linear hydride-type crosslinking agent represented by the formula MHDhDMH having a viscosity of 0.55 Pa.s at 25 ° C. and comprising approximately 0.8% by weight of hydrogen atoms. (G) Hydroxylated fluo HF: silanol-terminated polydimethyl siloxane of formula HO-D6-9-OH of a

viscosity of 0.3 Pa.s at 25 C.

  The following examples are given by way of illustration of the present invention without

  limit the scope of this description or the

appended claims.

Example 1 to 7

  Liquid injection molding compositions were prepared by first mixing the vinyl organopolysiloxanes and the fumed silica filler. The fumed silica described above was only treated with a cyclic tetramer. The fumed silica feed was treated in situ by adding 6.0 parts by weight of hexamethyldisilazane and 2.0 parts by weight of water. This mixture was heated at C under vacuum. Byproducts formed by water

  and ammonia were removed during the treatment.

  The remaining ingredients were then added and the resulting composition was injection molded.

  as shown in Table 1.

  CD o C co mnw r rq i [The i) rLoooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo .Ln I "-. R'3, r-'On 4 '"' q "" '' 00 OU

r-

ul> g -

  ## STR5 ## ## EQU1 ## where ## EQU1 ## where ## EQU1 ## where ## EQU1 ## - CDCD CDl 10 "qm 0OC O corc CNrcnCD CD Cà Lm r- ON (n Lr Ln 4 CcD rq q

O 0 I-

  Cd cd cd cd cd cd cd cd cd cd cd ooo

At - = 03 (

> sF_ o e) a2 o '. C)

0-00 0 0 0 - Where are you?

  ## EQU1 ## where ## EQU1 ## where ## EQU2 ## where ## EQU1 ## 4- nin cnorn 4-1.- <'- Io -i 1-iniO mmn -'- n A. 111-11.11 -i.'i 0 $ .ea> -1 -1e U) n'cie niv.eu u> <.- ldP (n r-4 ("8 l> 4t 8e

-l4- (n (n - (4J (C (-

  These examples clearly indicate that by increasing the vinyl-containing chain polymer content while maintaining the SiH / SiVi ratio constant, a higher hardness and tear strength material without loss is obtained.

  notable tensile strength and elongation.

  The storage stability and demoldability of these compositions were poor. In addition, the tearing resistances were not sufficient because of the absence of LVO.

Example 8

  The procedure of Examples 1 to 2 was repeated. 7 using the composition of Table 2. The stability of the storage and demoldability of this

composition were excellent.

Example 9

  The process of Examples 1 to 7 was repeated using the composition of Example 3. The storage stability and demoldability of this

composition were mediocre.

Table 2

Example 8

HVO1 / HVO2 * 70

VCO1 3.9

LVO 3.9

  Hydroxylated Flu 1.2 Smoked Silica 25.0 Precipitated Silica 4.0 Lamoreau Catalyst, ppm Pt 10 Diallylmaleate, ppm 500

RHC ** 0.88

LHC ** 0.30

  Hardened leaves 12 min. at 204.4 C Shore A hardness 40 Tensile strength, Pa 7929.2.103 Elongation,% 700 Tear resistance, kg / cm 41.07 Resilience Bashore 52 * blend achieved at 40 Pa.s & 25 C ** SiH number ratio / SiVi of about 1.7

Table 3

Example 9

HVO1 20.2

HVO2 43.0

VC02 1.0

LVO 4.7

  Smoke 31.1 Starch catalyst, ppm Pt 1.0 Methyl tetramer 0.015

RHC 1.0

  Hardened leaves 12 min. at 204.4 C Shore A hardness 50 Tensile strength, Pa 7405.2.103 Elongation,% 480 Tensile strength, kg / cm 41.07 Resilience Bashore 52

Claims (7)

  1. Organopolysiloxane composition, characterized   in that it comprises: (A) 100 parts by weight of a polyorganosiloxane vinyl component, comprising: (i) from 70 to 98 parts by weight of a high viscosity vinyl terminated linear organopolysiloxane having no not more than 25 mol% of phenyl groups and having a viscosity of from about 2 to about 1000 Pa.s at 25 ° C, (ii) from 1 to 15 parts by weight of a linear low viscosity organopolysiloxane having minus one vinyl end group per molecule, having a vinyl group content which may range from 0.01 mole percent vinyl groups to 60 mole percent vinyl groups, having a viscosity ranging from about 0.5 to about at 25 ° C. and having not more than mol% of phenyl group, and (iii) from 1 to 15 parts by weight of a vinyl chain-containing organopolysiloxane comprising from about 0.1 to about 25 mol% of vinyl groups, having a viscosity ranging from about 0.5 to about 100 Pa at 25 ° C and having not more than about 25 mol% of phenyl groups; (B) from about 5 to about 70 parts by weight of a filler or a combination of filler; (C) from about 0.1 to 50 parts per million based on all of the organopolysiloxane composition of a platinum catalyst; and (D) from about 0.5 to 25 parts by weight of an SiH group component selected from hydrogenated silanes and hydrogenated organopolysiloxanes. 2. Composition according to claim 1, characterized in that it comprises a first component packaged separately from a second component, each of the components may comprise all or part of component (A) and component (B); the first component comprising the total amount of component (C); and the second component comprising the total amount of constituent (D).   3. Composition according to claim 1 or 2, characterized in that the component (B) comprises: (i) fumed silica treated with a silazane or methyl silane and at least one part by weight of methyl silane; or (ii) silazane-treated precipitated silica, the weight ratio of fumed silica to precipitated silica being from about 5: 1 to about 10: 1; and in that said composition further comprises: (E) from about 1 to about 5 parts by weight of a hydroxyl-containing fluid organopolysiloxane having a viscosity of about 0.005 Pa.s to about 1 Pa.s. at 25C.   4. Composition according to claims 2 and   3, characterized in that each component may comprise all or part of the constituent (E). 5. Composition according to claim 3 or 4, characterized in that said filler is treated in situ. 6. Composition according to claim 1 or 2, characterized in that said vinyl-terminated organopolysiloxane of high viscosity, is represented by the general formula: R R R '' Vi - Si S0i. OSiVi I '.   Wherein Vi denotes a vinyl group, R is selected from monovalent hydrocarbon groups and halogenated monovalent hydrocarbon groups having up to about 20 carbon atoms, and x may   vary from about 100 to about 10,000.   7. Composition according to claim 1 or 2, characterized in that said organopolysiloxane of low viscosity is represented by the general formula: R R   Where R is selected from monovalent hydrocarbon groups and halogenated monovalent hydrocarbon groups having up to about 20 carbon atoms, R1 is the same as R with the exception of that at least one R1 group must: aelnmo; ops; ap s; T: o0 op 9qmUou ua% 5'66 UOZTAUa S'O UOXTAuaaP luvlaodzoo saueXOtTSAlodouvbzo sa- Tm.ed TsToqo Usa HTS sadnozb juenITsuoo al enb ao asazgoeUeo z no T uoTzuoTpusAez eI juvAFns uoT; 4Tsodwoo OT Se W e 8'0 ap eTaeA oe '0'u O 8'0 ap eaAre rs ee v e w e w e w SpUeTU lNTuA Sun e the SenBtuT; 89 ex auoqzeo ap saemoe Oz UOaTAUa J, nbsnç uUeA spu, 6ouuq s-uaelAouou squoqieDoopAq sadnoab sal a seuaeleAouou Z squoqavooapAq sadnoa sal TLaed $ sToqo uea 'io z / (o-t) OTS0: sln = o; op s T T T T T T T T 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5; 0O ap s; TIOM ap acqUou ua% uO2Tua g'O UO2TAUaP a; lodwoo 'SrAuTA sadnoab sap juu; odmoo euT $ qo auvxolTsAlodoubibo ITpal anb ao uS 9spU.9 eoIo z no T uoTZeDTpuaea VI JueATns uo: TsodooD' 6 * IAUTFA   adnoib a Ise TH adnoab Ines unnb o90 ue aSuT9gloegeo L uoT; DoTpugAaaS VI uNTS uoT; TsodmoD '8 OSL uo0TAu0 t UO2TAUap laTaeA; nad A; e' aIAUTA odnoab a eza9 SZ lO9Z 26U04 1i8 Re SiO (4_c) / 2 -o R represents a monovalent hydrocarbon group or a saturated halogenated hydrocarbon group having up to about 20 carbon atoms, ca a value ranging from 0.8 to 2.5, a value ranging from 0 to 2 and the   sum of f and g varies from 0.8 to 3.0.