FR2589832A1 - Packagings for polysiloxanes - Google Patents

Abstract

The invention relates to packaging. It relates to a packaging or pack containing a hardenable composition in a compartment from which it can be distributed by means of a propellent gas, characterised in that the composition comprises an organopolysiloxane and a hydrophobic filler. Use in particular in the medical field for producing dressings.

Description

 The invention relates to packaging or packaging for polysiloxanes.

 Curable polysiloxanes are given which can be cured by various means such as the moisture curing of single part compositions and the curing of two part compositions by mixing prescribed amounts of these parts which are then allowed to cure. room temperature or by heating to high temperature. In this way, we can manufacture cellular products or not for various uses. Various techniques have been proposed for preserving these materials in an uncured form until it is desired to convert them to the cured form.

 A proposed technique is to form a composition in two parts A and B which are packaged and kept separately before mixing them to obtain the cured product. Although this process can be used effectively for many products, it is not always successful, particularly in cases where special mixing requirements are posed, for example mixing materials of various viscosities or compatibilities or mixing materials in selected proportions. Other difficulties may arise if the mixing of the two parts is carried out manually intermittently by personnel unfamiliar with such products.

 Curable polysiloxane materials have been proposed for use in various applications in the automotive, building and other industries, and for medical use. We give compositions comprising two parts and which oblige the user to mix two liquids of very different viscosities in a determined ratio to obtain desirable results.

It is also necessary in certain cases to mix one of the parts of the composition before mixing the two parts together. For example, it has been proposed to use a composition in two parts curable at room temperature to form dressings for budding open wounds by a process in which the two parts of the composition are mixed and then it is poured into an open wound where the composition foams and hardens by giving an alveolar elastomer dressing.

Such compositions may for example comprise a poly (dimethylsiloxane) and a finely divided filler or "part A" and a catalyst or "part B" formed of catalytic material favoring the curing of the composition at room temperature according to the scheme --- ------------- - = SiO + HS # 4 Si-O-Si + H2. In this way, comfortable, non-adherent dressings can be produced which conform to the contours of the wound and which are, among other things, soft and elastic and somewhat absorbent.

Although it is possible to take advantage of this proposal, the formation of thick mud in the part
A during the storage of the compositions used requires not only to mix parts A and B well together but also to thoroughly mix the part
A before mixing it with part B. Thus, the step of mixing part A of the composition immediately before use is a critical step in order to ensure the formation of a suitably alveolar, hardened and uniformly elastic product. and in order to take advantage of the considerable advantages which the process allows. When this step, or the dosage of ingredients, is not done properly, or not at all (as can happen in practice), the result is dressings of poor quality.

 It is complicated to rectify an incorrect mixture of compositions of this kind because very often, the fact of incorrect mixing is not noticed until the supposedly curable composition has been applied in the intended position. Once it has been found that a properly hardened mass does not form, it becomes desirable to remove the defective material, clean the area and achieve the desired result by correct application or by some other means. These corrective operations are complicated and inconvenient, especially in cases where the product is used for the treatment of an open wound, for example on the human body.

 It is common to package materials in the so-called aerosol form, particularly for surface coating applications. The materials which are usually packaged in this manner are mainly formed from liquids or solutions of relatively low viscosity and which hardly require mixing with any other ingredient before being ejected from the package. It has been proposed to extend the use of packaging in the form of an aerosol to curable compositions in two parts. For example, in patent GB 861,448, a package is described comprising a pressure-tight container having an outlet orifice. closable and containing a polymerizable material such that at a temperature below about 660 C, it quickly and completely converts to an organic polymer, only when it is taken out through the orifice, and a propellant which is gaseous at the ambient temperature and pressure, this propellant being present in sufficient quantity and being capable of exerting sufficient pressure inside the container to expel the polymerizable material through the orifice. In a preferred embodiment, an agent serving to activate the polymerization is maintained, with a volatile propellant, physically separated from the polymerizable material in a compartment from which it can be expelled through an orifice to a mixing chamber in which one mixes the polymerisable material and the activator under reduced pressure before expelling them into the atmosphere.

 It has been found impractical to package certain known compositions of curable charged polysiloxane using known packages of the aerosol type. It is difficult to package loaded materials having a thicker consistency than liquid polysiloxånes and yet more fluid than pasty liquids, and the invention is particularly concerned with the packaging of these materials.

 An object of the invention is to provide an improved packaging containing a curable composition in a compartment from which it can be dispensed by means of a propellant gas.

 Another object of the invention is to provide a two-part polysiloxane composition capable of being dispensed without the need for the user to dose or manually mix the two parts of the composition.

 the invention provides a packaging or packaging containing a curable composition comprising an organopolysiloxane and a filler, this composition being present in a compartment from which it can be dispensed by means of a propellant, packaging characterized in that the filler comprises a filler hydrophobic.

 the fillers suitable for use in the invention include those which are prepared by treating silica finely divided by alkylhalosilanes or alkylsilanols or alkyl siloxanols. Suitable silanes include those represented by the general formula (R) aSi (X) b wherein each R represents a lower alkyl or aryl radical, for example a methyl radical, each X represents a hydroxyl group or a halogen atom , for example Cl or Br, a and b are each 1, 2 or 3 and a + b = 4. Examples of these materials are trimethylmonochlorosilane, dimethyldichlorosilane and trimethylmonohydroxysilane. The hydroxysilanes can be prepared for example by hydrolysis of suitable alkyldisilazanes; for example, a reaction product of silica and hexamethyldisilazane in the presence of water is considered to be a preferred filler. suitable fillers have a specific surface of about 50 to 300 m2 / g and preferred materials have a specific surface of about 100 to 250 m2 / g.

 These hydrophobic fillers used in the invention can be prepared for example by adding silica and alkyldisilazane to the other ingredients of the composition during the preparation of the composition. However, in the compositions using polysiloxanes containing hydroxyl functions, this means is not preferred. In such cases, it is best to prepare the hydrophobic filler in a separate operation and add it to the other ingredients.

 A package according to the invention may contain a composition intended to serve as a curable composition in a single part; preferably, however, the composition is a constituent part of a curable composition which can, after mixing its constituents, cure at room temperature or at an elevated temperature to form a mass of polysiloxane. These compositions can comprise a part A and a part B for example, the parts being of similar or different viscosities and supplying the constituents of the curable composition which interact or one of which catalyzes the other, so that they are can be stored separately to avoid premature consumption of organofunctional groups.

 A package according to the invention can be used in the formation of a hardened layer or a hardened body of crosslinked polysiloxane having the desired characteristics. For example, the composition can be chosen so as to form products which may or may not be cellular, rigid or elastomeric. Preferably, the materials are chosen so as to form elastic elastomeric products suitable for use as medical dressings, dental materials, seals formed in place, and composition for casting and molding. The ingredients of the composition can be chosen so as to provide an effective curing mechanism at room temperature or at a higher temperature and capable of ensuring the desired curing in a chosen period of time. For example, useful materials can be prepared by using organopolysiloxanes containing siloxane units having a silicon-bonded hydrogen atom (hereinafter called '1alkylydrogénopolysiloxanes1,) together with organopolysiloxanes containing siloxane units providing a hydroxyl group bonded to silicon (hereinafter "hydroxypolysiloxanes".) or with organopolysiloxanes containing siloxane units having an alkenyl group bonded to silicon (hereinafter called "alkenylpolysiloxanes") in the presence of suitable catalytic material. Suitable crosslinking and chain stopping agents may be included in the composition. Alkylhydrogenopolysiloxanes and hydroxypolysiloxanes and catalysts to promote their reaction to form cured foams may be, for example, as described in general in G3-A - 798669, 867619 and 1522637.

dans laquelle chaque R représente un radical alkyle inférieur ou phényle, par exemple un radical méthyle, vaut O, I ou 2, n vaut 1 ou 2 et la somme p+q vaut 1, 2 ou 3. les alkylhydrogénopolysiloxanes peuvent aussi comprendre des unités

dans lesquelles R est tel, qu'indiqué ci-dessus et n vaut 1, 2 ou 3. les réactions de durcissement des compositions préférées dépendent de la présence de quantités appropriées des fonctions entrant en interaction et on peut choisir en conséquence l'alkylhydrogénopolysiloxane. Il est préférable que chaque R représente un groupe méthyle.De préférence, les groupes terminaux de lwalkylllydrogéno- polysiloxane sont des groupes R3Si0 1/2 dans lesquels chaque R représente un groupe méthyle. Des alkylhydro génopolysiloxanes appropriés comprennent ceux qui contiennent des unités MeHSiO avec ou sans la présence d'unités Me2SiO et qui ont des viscosités de l'ordre d'environ 0,001 à environ 01i ra.s, de préférence ceux qui sont formés d'un mélange d'une viscosité de 0X001 à 0,05 Pa.s.Alkylhydrogenopolysiloxanes suitable for use in the invention include polymers containing units of the general formula

in which each R represents a lower alkyl or phenyl radical, for example a methyl radical, is worth O, I or 2, n is worth 1 or 2 and the sum p + q is worth 1, 2 or 3. the alkylhydrogenopolysiloxanes can also comprise units

in which R is as indicated above and n is 1, 2 or 3. the curing reactions of the preferred compositions depend on the presence of appropriate quantities of the interacting functions and the alkylhydrogenopolysiloxane can therefore be chosen. It is preferable that each R represents a methyl group. Preferably, the terminal groups of lwalkylllydrogénopolysiloxane are groups R3Si0 1/2 in which each R represents a methyl group. Suitable alkylhydro genopolysiloxanes include those which contain MeHSiO units with or without the presence of Me2SiO units and which have viscosities on the order of from about 0.001 to about 01. ra.s, preferably those which are formed from a mixture with a viscosity of 0X001 to 0.05 Pa.s.

dans laquelle chaque Q représente un groupe OH ou un groupe alcényle de 2 à 4 atomes de carbone inclusivement par exemple un groupe -CH=CH2 ou CH-CH=CH2, chaque R représente un radical alkyle inférieur ou phényle, par exemple un radical méthyle et m vaut 1 ou 2. Ces polysiloxane comprennent aussi des unités

dans lesquelles R est tel qu'indiqué ci-dessus et n vaut 1, 2 ou 3.Ces matières sont de préférence des liquides et on les choisit de façon que leur fonctionnalité soit appropriée, compte tenu du degré voulu d'allongement de channe et de réticulation pendant le durcissement de la composition On préfère utiliser des polysiloxanes qui sont essentiellement difonctionnels, c'est-à-dire des t ,u)-dihydroxypolysiloxanes ou desE ,#-dialcénylpolysi- loxanes. Des matières appropriées comprennent dests -di-hydroxipolysiloxanes ayant une viscosité d'environ 0,5 à 25 Pa.s à 250C, c'est-à-dire un poids moléculaire moyen en nombre de l'ordre de 20000 à 80000 environ.Suitable hydroxypolysiloxanes and alkenyl polysiloxanes include polymers which include units of the general formula:

in which each Q represents an OH group or an alkenyl group of 2 to 4 carbon atoms inclusive, for example a group -CH = CH2 or CH-CH = CH2, each R represents a lower alkyl or phenyl radical, for example a methyl radical and m is 1 or 2. These polysiloxane also include units

in which R is as indicated above and n is 1, 2 or 3. These materials are preferably liquids and they are chosen so that their functionality is appropriate, taking into account the desired degree of chain elongation and of crosslinking during the curing of the composition It is preferred to use polysiloxanes which are essentially difunctional, that is to say t, u) -dihydroxypolysiloxanes or desE, # - dialkenylpolysiloxanes. Suitable materials include dests -di-hydroxipolysiloxanes having a viscosity of about 0.5 to 25 Pa.s at 250C, i.e. a number average molecular weight in the range of about 20,000 to 80,000.

Preferred materials have viscosities on the order of about 1.5 to 15 Pa.s, in particular from 1.8 to 2.6 Pa.s, and mainly comprise de-unets of the general formula R2SiO and two units of the general formula R2 (OX) SiO1 / 2. Suitable alkenylpolysiloxanes also include polysiloxanes blocked at their ends by # dimethylvinyl groups, for example those having viscosities of up to about 85 Pa.s, preferably from 45 to 65 Pa.s at 250C, and polydimethylsiloxanes blocked at their ends with phenylmethylvinyl groups, for example having viscosities at 250C of 0.25 to 1OPa.s. In the preferred ones, each R represents a methyl radical.

In preferred compositions according to the invention, the preferred polysiloxanes containing hydroxyl and alkenyl functions therefore form polysiloxane chains of appreciable length and this is desirable given the flexibility and the elastomeric properties required of the product resulting from the curing of the composition. If desired, organofunctional polysiloxanes of relatively low molecular weight, i.e. short chain, can also be included in the composition. preferred materials include g, w-polysiloxanediols containing up to 25 dimethylsiloxane units in the molecular chain.

 it is also desirable to include in the composition appropriate amounts of materials of higher functionality, as crosslinking agents.

suitable crosslinking agents include materials containing 3 or more functional groups per molecule, for example hydroxyl groups. Preferred foam-forming compositions include an alkoxysilane and / or a condensation product thereof capable of combining with three or more hydroxypolysiloxane molecules, with release of the alcohol corresponding to the alkyl radicals, for example methyltrimethaxysilane, n-propyl orthosilicate and ethyl polysilicate.

the formulating compositions of cellular material and intended to be used in the invention preferably comprise monofunctional hydroxylated compounds of silicon effective as chain stop agents. Such bodies influence the structure of the cellular materials formed by means of the composition and their use is very preferred when it is desired to mainly open cell materials. suitable monofunctional hydroxy compounds include monohydroxysilanols and
-------------------- monohydroxysiloxanols which can, for example, contain short-chain siloxanes containing, for example, up to about 25 siloxane units per molecule and having a terminal hydroxyl group or pendant, or a material of the general formula R3SiOH in which each R can be, for example, a lower alkyl group, for example methyl, or a phenyl group. Examples of these materials are:

(nonameth, rltetrasiloxans-1-ol) (heptamethyltrisiloxane-2-ol) and
(diphenylmethylsilanol)
The amounts used of the various materials can be varied within relatively wide ranges without departing from the spirit of the invention. However, to obtain elastomeric foam materials having densities of about 120 to 210 kg / m3, within 3 minutes of mixing the ingredients at room temperature, it is preferred to use various preferred materials in amounts within the following ranges ::
Material Parts by weight
Quantities Quantities
Particular favorites
lierly
preferred z, wdihydroxyrpolysiloxanes, 100 100
viscosity from 1.8 to 2.6 Pa.s Low weight Rydroxypolysiloxane 0-60 5-20
molecular Âlkylhydr ogé nopolysiloxane 5-35 15-30
Cross-linking agent 0-7 3-5
Chancellor 0-20 5-15
Charge 5-35 5-15
Catalyst: 3 to 8% of the weight of the above constituents.

The compositions intended for the preparation of somewhat elastic elastomeric or gelatinous products may advantageously be those in which the chain elongation and / or crosslinking reactions mainly comprise vinyl addition reactions and therefore cannot release quantities of hydrogen causing foaming. The quantities of materials used can be varied within wide ranges depending on the materials used and the properties required of the product. For example, preferred materials can be used in the following quantities:
Material Parts by Weight
Quantities Quantities
favorite particu
lierly
preferred d, W-di-alkenylpolysiloxane, 100 100
viscosity 1.8 to 2.4 Pa.s #, W-di-alkenylpolysiloxane 0.25 to 0-40 30-40 10 Pa.s Dimethyl- and 0.5-15 copolymer 10-15
polymzthylhydrogensiloxanes
Hydrophobic load 5-50 40-48
Platinum catalyst 0.05-Cs50 0.08-0.16
In a packaging according to the invention, the composition may title contained in a compartment or chamber to be expelled at the same time as a propellant gas. Alternatively, the expulsion may be carried out by a membrane placed in the chamber and which is capable of act on the composition under the influence of a propellant contained in the chamber. In this latter arrangement, the propellant gas can be between the membrane and a surface of the chamber so that it is not expelled from the chamber with the composition.

the propellants suitable for Entre mixed with the composition are inert with respect to the ingredients, do not detrimentally influence the product, do not detrimentally influence the hardening of the product and are preferably soluble in the composition. For many uses, nitrogen and liquefied gases known for use in aerosols are suitable, including hydrocarbons, for example methane, ethylene, ethane, propane, neopentane and many halogenated hydrocarbons , especially fluorinated hydrocarbons, for example methyl fluoride, trifluoromethane, monochlorodifluoromethane and dichlo rodjfluoromethane,
A package according to the invention preferably contains a component part (part A) of a two-component composition. the packaging preferably comprises a second compartment or chamber containing the second component (part 3) intended to be mixed with the first component to form a cured product. This second chamber may other located inside or near the first and, preferably, the structure and the arrangement are such that the packaging can be actuated so that material can be distributed simultaneously from the chambers, in predetermined proportions.

 Preferably, the package has a mixing nozzle through which the two components can be brought to mix them together. the second bedroom can be of a similar or different structure from the first. Preferably, propellant gas is used to dispense material from the second chamber. In cases where it is necessary to mix small proportions of part B with large proportions of part A, or when part B has a viscosity substantially lower than part h, it is preferable to package part 3 so that it is expelled by propellant gas as described above.

In cases where it is necessary to mix similar proportions of parts A and B having similar viscosities, it is preferable to package each part in a chamber from which it can be expelled under the effect of a propellant on a membrane provided in bedroom. The chamber can be designed to dispense individual or preferably multiple doses per package, as desired. preferably humidity-proof chambers made of plastic, metal or glass are used.

A package according to the invention can comprise, for example, two chambers, one inside the other. Thus, the composition (i.e. the part
A) can be stored in an outer packaging compartment and part 3 can title stored in an interior compartment of the packaging, as well as compressed propellant. When it is necessary to use them, the materials coming from the interior compartment can be brought into the exterior compartment, mix the constituents, for example by vigorous stirring and distribute the whole under the pressure of the propellant.

In another arrangement, a package according to the invention may comprise two adjacent compartments each containing a part of a composition. one or all of the parts may comprise organopolysiloxanes and a hydrophobic filler. These compartments can be arranged and designed so as to discharge their contents in desired proportions, passing through a collector, to a mixing nozzle, when necessary and successively until the compartments are empty.

 The packaging according to the invention has various advantages. In particular, the composition can be dispensed from the package without difficulty after prolonged storage. In addition, the packages according to the invention can be designed for simple manual actuation and can contain enough composition for use in situations where it is likely that relatively small quantities will be required at any one time. of composition and where it is particularly important to ensure an appropriate mixing of the parts of the composition with the minimum of attention on the part of the operator, and where contamination of the composition must be avoided.

packaging is therefore particularly advantageous in the field of medical dressings.

In order that the invention may be more fully understood, the description is given below of packages chosen as examples, containing curable compositions according to the invention,
In the drawings, FIG. 1 is a diagram of a packaging of the "canister in canister" type and FIG. 2 a diagram of a packaging of the "canister in canister" type.

 Each of the curable compositions is capable of curing at room temperature when mixed with a second suitable component.

the examples of composition 1 to 5 constitute parts A intended to be mixed with a catalyst to give an elastic foam material. the compositions comprise the following materials, in the quantities indicated, by weight
Composition example Material 1 2 2 4 d, -hydroxypolysiloxane 1 100 100 100 100 50 #, W-hydroxypolysiloxane 2 - - - - 50 Low-weight hydroxysiloxane
molecular 1 10 10 50 50 10
Low-weight hydroxysiloxane - - - - 15
molecular 2
Alkylhydrogenosiloxane 10 20 10 10 10
Crosslinking agent 4 4 4 4 Vinyldimetilylsilanol - - 5 -
Stop Agent:
diphenylmethylsilanol 10 10 - -
heptamethyltrisiloxane-2-ol - - - - 7.5 nonamethyltetrasiloxane-1-Ol - - - 10
Load 10 10 15 15 10
#, W-hydroxypolysiloxanes 1 and 2 used were mixtures of deot - W-di-hydroxypolydimetylsiloxanes having viscosities at 2500 of approximately 2 Pa.s and approximately 13.5 Pa.s respectively (that is i.e. respective number average molecular weights of 21,000 and 40,000) with minor amounts of cyclic polydimethylsiloxanes.

 low molecular weight hydroxysiloxane 1 included, W-hydroxypolydimethylsiloxanes containing 1 to 23 siloxane units. the low molecular weight siloxane 2 included dihydroxypolydimethylpolymethylvinylsiloxanes containing on average, respectively, about 3.5 dimethylsiloxane units per molecule and about 2 methylvinylsiloxane units per molecule.

 The alkylhydrogensiloxane 1 used was a mixture of methylhydrogenopolysiloxanes blocked at their ends by trimethylsiloxy groups and having a viscosity at 25 C of approximately 0.02 to 0.04 Pa.s and a content of SiH group (expressed in X) d 'about 1.6?.

The crosslinking agent used was n-propylee orthosilicate
The charge used was cracker 2000 ", indicated as being a material prepared by treatment of silica finely divided by hexamethyldisilazane to obtain a hydrophobic silica and as having a specific surface of 170 + 30 m2 / g and a silica content of '' at least 97 sb.

 Each of the composition examples was aged at 6200 for 8 weeks. there was no sign of separation from any of the compositions.

Each of the composition examples, when mixed with 6 # (on the weight of the composition examples) of stannous octoate, foamed within 5 minutes to give a substantially open cell foam which hardened to give an elastic cellular product.

 the examples of composition 6 and 7 respectively constituted parts A and 3 intended by way of mixing together to give a hardenable composition suitable for the formation of joints in situ.

the compositions included the following materials, in indicated amounts, by weight
Material Composition example
6
dEsw-alkenylpolysiloxane 1 46.0 43.0
d, # - alkenylpolysiloxane 2 54, o 54.0
Load 2 29.0 29.0
0.2 platinum catalyst
Alkylhydrogenosiloxane 2 --- 3.3
Compositions 6 and 7 were prepared by first reacting 4.2 parts by weight of low molecular weight hydroxysiloxane 1, 3.3 parts by weight of low molecular weight hydroxysiloxane 2, 5.7 parts by weight d water, 22.7 parts by weight of hexamethyldisilazane and 100 parts by weight of silica (Cabosil MS-75) to produce the hydrophobic filler 2. The hydrophobic filler was then mixed with the other ingredients.

 The i-alkenylpolysiloxane 1 used was a high molecular weight polydimethylsiloxane polymer blocked at its ends by dimethylylvinyl groups and having a viscosity (Brookfield RvF) of 4 to 6 Pa.s at 2500.

 The #, # - alkenylpolysiloxane 2 used was a polydimethylsiloxane polymer blocked at its ends by dimethylvinyl groups and having a viscosity of approximately 0.45 Pa.s at 2500.

 The alkylhydrogenosiloxane 2 used was a copolymer of polydimethyl- and polymethylhydrogenosiloxanes having a viscosity of 0.004 to 0.006 Pa.s at 250C and a content of SiH groups (expressed in ss of H) of approximately 0.89 to 0.83.

Example 1
The examples of composition 1,2, 3, 4 and 5 were packaged in "can in can" packaging (FIG. 1), as follows. 1.8 g of stannous octoate were introduced into a compartment formed by a capsule which could be broken, in the form of a glass tube 10 containing a steel rod 12. A mixture of compressed nitrogen and 2.0 parts by volume of liquid pentane, under a pressure of 7 bars and the tube was sealed around the rod. Qn placed
in a compatiment 30 g of part A of the composition / form by a metal container 14 and the sealed tube was placed in part A, inside the metal container, so as to form a packaging having an interior chamber 16 and an outer chamber 18, the inner chamber containing the catalyst or part B and the outer chamber containing the part A. The metal container was sealed with a cap 20 comprising a discharge nozzle with valve 22 and means making it possible to actuate the rod to release the contents of the inner chamber so that it mixes with the contents of the outer chamber. When we wanted to distribute the contents of the package, we actuated the rod 12 to allow the catalyst, nitrogen and pentane to come into contact with part A and the packaging was agitated to mix the materials. The valve was actuated to allow the release of the mixed materials from the packaging passing through the nozzle 22, under the pressure exerted by the gases present in the mixture.

 Each of the composition examples was thus distributed in the form of a bead of mixed composition and the packaging could be moved in order to distribute a mass of the material at the desired location, until the packaging was at least practically empty. the bead foamed to some extent while it was being dispensed and the foaming and curing reactions were at least substantially complete within about 5 minutes after the material was expelled, yielding a mass of crosslinked cellular polysiloxane.

Example 2
The examples of composition 1, 2, 3, 4 and 5 were packaged in a canister-on-canister package "(FIG. 2) as follows. In a metal container 30, 8 g of stannous octoate were introduced as catalyst thus that 4.0 g of a liquid which was intended then to form propellant gas for "expulsion with the composition, ie" Freon "12. The container was closed by means of a non-return valve 32 and its outlet was screwed into a first orifice 36 of a manifold block 34. 100 g of part A were introduced into a compartment formed by a metal container 40 having a membrane lining 42 fixed near an outlet of the container. Between the container and the membrane were 10 g of liquid which was intended to then ensure a pressure of propellant gas to act on the membrane and thus distribute the composition.

The container was closed by means of a non-return valve 44 and its outlet was screwed into a second orifice 38 of the manifold block. the first port 36 and the second port 38 of the manifold block were designed to distribute, upon actuation of the non-return valves, volumes of parts A and B dosed according to the desired mixing ratio of the constituents, that is to say say 100 parts by volume of A for 6 parts by volume of B.

The composition delivered by the collector was discharged through a nozzle 46 of the disposable static mixer type. When it was desired to distribute material, the containers were moved relative to the collector in order to actuate the two non-return valves 32, 44. the propellant gas contained in each container made flow the composition coming from each can 302 40 to the collector 46 and passed it through the first and second orifices 36, 38 and the nozzle 46. the parts A and 3 were thus metered by the gas pressures and the orifices and mixed by the static mixer. When a desired amount of the composition had been dispensed, the containers were allowed to move away from the manifold to close the valves 32, 44. To prepare for a subsequent dispensing operation, the nozzle was removed and replaced with another.

 The composition dispensed from the nozzle was in the form of a bead which hardened to form a mass of crosslinked polysiloxane within 3 minutes after leaving the nozzle. Each of the cords began to foam within 10 seconds of leaving the static mixer.

example 3
Equal volumes (100 g) of compositions 6 and 7 were packed in a "can on can" packaging similar to that of FIG. 2 but comprising two compartments each of which was formed by a metal container having a fixed membrane lining. near an outlet from the chamber, similar to the metal container 40 used for examples of composition 1 to 5 in Example 2. Each container contained, between its wall and the membrane, 10 g of Préon 12 which was intended to ensure then a propellant pressure capable of acting on the membrane to distribute the composition. Each container was closed by means of a non-return valve and the valves were fixed in orifices of a manifold similar to that which is used in example 2. the orifices were connected with a mixing nozzle used to mix the two compositions, practically in the manner described in example 2. However, the orifices were arranged so that volumes equal ux of the two compositions were delivered, under the influence of the propellants, to the mixing nozzle when the valves were opened. It was thus possible to distribute the compositions 6 and 7 in predetermined volumes so that they mix when the packaging is actuated.

 the composition dispensed by the nozzle was in the form of a bead which hardened within 10 minutes, giving an elastic and uniform non-cellular product when it was heated to a temperature of 1500C.

Claims (10)

 R%: VElTDICATI oeT, .s  lo mribailage or packaging containing a curable composition comprising an organopolysiloxane and a filler, this composition being present in a compartment from which it can be distributed by means of a propellant, characterized in that the tank a comprises a hydrophobic filler.  2. Packaging according to claim 1, characterized in that the composition is contained in a membrane (42) placed inside the compartment (40) so that propellant placed between the membrane and a surface of the compartment can be brought to act on the membrane to distribute the composition.  3. Packaging according to claim 1 or 2, characterized in that it has a mixing nozzle (46) through which the composition can be passed as well as a second composition to form a curable composition.  4. Packaging according to claim 1, characterized in that the composition is a constituent part of a composition which can, when mixing its constituent parts, harden giving a mass of elastic polysiloxane, cellular or not.  5. Packaging according to claim 3, characterized in that a constituent comprising a catalyst favoring the hardening of the composition is contained in a second compartment of the packaging at the same time as a propellant and the compartments are constructed and arranged so that the The packaging can be actuated to deliver predetermined proportions of the component parts through the mixing nozzle.  6. A package according to claim 3, characterized in this tool comprises two compartments, each according to claim 1 or claim 2, the compartments being constructed, and arranged so that the package can be actuated to deliver predetermined proportions of the tarties components through the mixing nozzle.  7. Packaging according to claim 1 or 2, characterized in that a constituent comprising a catalyst promoting the hardening of the composition is contained in a second compartment (16), inside the first mentioned compartment (18), the structure and arrangement being such that the catalyst can be made to mix with the composition when desired.  8. Packaging according to any one of claims 1 to 7, characterized in that the filler is a product of the treatment of silica with hexamethyl disilazane in the presence of water, having a specific surface of approximately 100 to 250 m2 / g .  9. Packaging according to any one of claims 1 to 8, characterized in that the composition comprises a, tÂ) -dihydroxypolydimethylsiloxane and a methylhydrogenopolysiloxane blocked at its ends by trimethylsilyl groups.  10. Packaging according to any one of claims 1 to 8 characterized in that the composition comprises a d, Wdi-vinylpolydimethylsiloxane and a copolymer of polydimethyl- and polymethylhydrogenosiloxanes.