DE2026079A1 - Composite materials based on organopolysiloxane - Google Patents

Description

EH ψ Zirmstein sen. - Dr. E. Assmann aittiäeigsberger - Dipl. Phys. R. Holzbauer

iDr.F. Zumstein jun.

.? -o t β η t α η w ä I t e

S Min ch rn 2, Bräuhawstraße 4/111

SO 3350

JiHONS-POULENC S.A., Paris, France

¥ e; r tape based on organopolysiloxane.xane

The v-OYllet * & Qäie invention relates to novel Varbundmaiier all who Zvi ropes particular as membranes to carry out Gasaustbansßhvorgärigen two different atmospheres or LAT see a gas!; or a mixture of gas and a liquid can be added and consist of an organic organopolysiloxane clay / bond with a material with mesh.

The expression. "Material mesh"v; ith used Mer, a ma / efcien by V to designate knitting, knitting or knotting of yarns obtained material.

Composite materials have already been described which contain an organopolyslloxane elastomer and a material with meshes (for example in Jaoanl's application £ 687/1967 * of American patent 2 966 2) 5 and French patent 1 yjj> 70J5). The elastomers and procedures described in these publications result in materials in which the elastomer layer can be very thin, being free of holes. The organopolysiloxane elastomers used according to the various patents, however, require the application of heat to dry them when they are used in solution (see the above-mentioned Japanese application) or

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for causing a peroxide to decompose (see the American and French patents cited above). One such Heat to temperatures that are between 50 and 175 ° C or higher, represents a significant energy consumption and can also be a. Cause deterioration in carrier gain. The crosslinking by irradiation, which in the fran-. French patent 1 393 703 is also provided, also requires a suitable system and an energy consumption.

The present invention relates to thin microholes free Composite materials comprising an organopolysiloxane elastomer and a material with mesh and light at room temperature can be made ^

In particular, the invention relates to composite materials with a total thickness between 120 and 350 μ, which consist of

a film made from an organopolysiloxane composition which can be vulcanized at room temperature under the action of mass in liquid or vapor form is and an a, ta'-dihydroxylated diorganopolyslloxanol and a contains a crosslinking agent consisting of a silane, polysilane or slloxane with more than two hydrolyzable groups,

and a material with meshes that by partial penetration one of the surfaces is fixed,

is formed.

Compositions of the type used in the present invention have already been described in the literature. So are in the French patents 1 198 749 and their addition 74 579, 1 248 826, 1 314 649, 1 359 240 and 1 432 799 at room temperature under the action of water in the liquid or vapor state vulcanizable compositions described, at which hydrolyzable silanes are used as crosslinking agents. Examples of such silanes are the organotrialkoxysilanes, Organotrlacyloxysilane, Organotriaminosllane, Organo -

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called triaminöoxysxlane and organotrisiminoxysilane.

To improve the mechanical properties of the films Elastomers! it is advantageous in the vulcanizable composition Bring fillers.

The proportion of fillers should be 40 wt .- $, based on the total weight of the composition, and the maximum diameter of the parts should not exceed 0.1μ. Fillers that are particularly suitable are finely divided silicas (pyrogenic or obtained by precipitation Silicas), which relate to the characteristics given above borrowed correspond to the grain size. These fillers can be used as such or after pretreatment with an organopolysiloxane, for example in accordance with the procedure described in French patent specification 1 520 6 ^ 3.

In addition to the dihydroxylated siloxane, the crosslinking agent and optionally fillers can ^1, the compositions also contain pigments or various additives. In particular, a diorganopolysiloxane can be incorporated into the compositions, the chain ends of which are blocked by trimethylsilyl groups and which plays the role of a plasticizer or plasticizer.

A particularly suitable composition for practicing the invention contains methyltriacetoxysilane and as a crosslinking agent as a filler a pyrogenically obtained silica with a high specific Surface in the form of particles with a diameter between 10 and 40 πΐμ, this silica previously with a Organopolysiloxane was treated.

The material with mesh can be a woven fabric, a knitted fabric, a knitted fabric or be a network. In particular, it is when the Arrangement of a material with a certain elasticity is desired, it is advantageous to use a knitted or knitted fabric.

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the. The chemical nature of the material is not critical. It it is possible to use a material made from natural fibers (e.g. cotton) or synthetic fibers (e.g. polyamide, Polyester, polyacrylonitrile) is made. ·

The diameter of the yarn, the monofilament or multifilament yarn can be and form the material with meshes, is preferably a puncture of the thickness of the film made of elastomer to which the material is applied. Given the particular type of connection of the material with meshes with the elastomer (partial penetration into a surface in the course of vulcanization) it is desirable not to use yarns whose Radius exceeds the thickness of the film if you want a sufficiently strong bond. Obviously there aren't any lower limit for the diameter of the yarns other than that resulting from the materials available on the market.

A method for producing the composite materials according to the invention consists of:

a) to pour the organopolysiloxane composition in the form of a film of suitable thickness onto a working support without adhesion, so that an end product with a thickness between 120 and 550 μ is obtained; an organosilicon sheet from 60 to 150 p. is generally suitable?

b) the film moisture for a few seconds to a few Suspend minutes to cause vulcanization of the elastomer to begin,

c) on the film, the surface of which is still adhesive, the material with mesh while exerting a slight pressure - .. to put on and '

d) the vulcanization in the presence of γοη moisture "zu®nd @ .go to leave and the composite material from the working document to separate.

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Fries on the work surface can be done with conventional pouring devices, for example by means of a casting machine with a doctor blade, be made. However, the precautionary measures must be taken when one is vulcanizable by moisture Compositions used, i.e. that the composition should be kept in the absence of moisture before pouring »

The working document can consist of a film made of a material, to which the composition does not adhere, for example from a film made of polytetrafluoroethylene., polyethylene or paraffin paper.

In general, the work sheet is slightly matted in order to facilitate subsequent manipulations of the composite material.

The thickness of the elastomeric film can easily be adjusted, by determining the distance between the mouthpiece of the casting machine, the distance that separates this mouthpiece from the work surface, or adjusts the ratio between the output of the casting machine and the speed of movement of the carrier substrate.

It is necessary to apply the material with a mesh while the surface of the film is still adhesive, but in order to avoid excessive penetration of this material, it is desirable that this application be made not immediately after the film is formed, but several tens of seconds to several Minutes thereafter, depending on the composition used (especially the choice of crosslinking agent) and the moisture content. This result can easily be achieved by arranging the device for applying the material with meshes in such a way that the sheet of elastomeric material is exposed to moisture for the desired period of time before this material is applied to it.

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The pressure required to mesh the material in Getting the elastomer to penetrate is little. Considering the diameter of the yarns and the mesh openings and the state of vulcanization of the composition during application, this pressure is generally between 0.05 and 0.3 bar.

When the material is applied with mesh on the sheet of ßlastomerem the vulcanization is allowed to proceed until it is finished. It should be noted that if you have one for via steam If you have chosen a permeable working mat, it is possible to mesh the membrane shortly after the material has been applied in the form of a roll as vulcanization proceeds in the roll. The work document is generally made by the membrane separated at the time of use of the latter.

The invention is to be explained in more detail below with reference to the figures of the drawing.

Fig. 1 shows schematically an apparatus which can be used to carry out the method described above »

This device has the following parts:

a tight vessel 1, which is used to hold the organopolysiloxane composition 2 is determined

Means, for example a piston 3> around the composition in a pouring device 4, which is connected to the vessel 1 is to lead

Drums 5 and 9, which serve to hold the working document 8, the is withdrawn from the Rolls 6, to carry and guide,

a feed roller 10 for the material 11 with meshes and a Drum 12 on which the entire material from the work sheet and the composite material is rolled up.

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The production of the composite material with the aid of this device is simple. By pressing in the piston J5, with the help of the casting device 4, a film 7 is formed on the work surface 6. The elastomeric film then runs through a distance that is generally between a few tens of centimeters and a few meters, depending on the type of composition, the degree of humidity and the running speed of the working document, with vulcanization beginning during this distance. At the level of the drum 9, the material 11 with stitches, which is fed from the roll 10, is guided against the film 'J.

The penetration of the material with meshes in the film can through Applying a moment of resistance to the roller 10 is set will.

The overall arrangement of the working document-composite material passes through again a certain distance and is then rolled up on the drum 12.

It's easy to apply the material with mesh on top of the Foil made of Elastcmerem in the desired vulcanization stage by adjusting the distance between drums 5 and 9 separates, and / or the speed of the drum 12 adjusts.

Another method for producing the materials according to the invention consists in first of all, for example by casting, forming a film from the organopolysiloxane elastomer, the thickness of which is 30 to 80 % of the thickness desired for the organosilicon part of the materials, and then exposing this film to moisture for a few minutes, in order to achieve partial or complete vulcanization of this film, one or more layers of the same composition are then applied to this film and finally the material is applied with meshes using the method described above.

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This process can be carried out with the aid of a device as shown schematically in Pig * 2. This apparatus is identical to that shown in Fig. 1, but also includes one or more devices on ,, allowing to apply one or more additional layers 7 ¹ of elastomers on the film 7. The additional device or devices have a tight vessel I ¹ which is intended to receive the organopolysiloxane composition 2 'and is connected to a pouring device 4 *, as well as devices such as a piston jj ¹ to. to lead the composition into the pouring device.

This second mode of operation brings greater security in the manufacture of materials that are free from micro-perforations are. It also makes it possible to precisely adjust the penetration of the material with meshes into the organosilicon elastomer, as this material only penetrates into the second (or last) elastomer layer.

The composite materials according to the invention are in particular due to the complete absence of micro-perforations in the active layer (made of organopolysiloxane elastomer) is of interest. she can therefore be used in various gas exchange processes, especially if these are processes in the presence of oxygen and carbon dioxide and / or nitrogen, due to their excellent selectivity towards these gases (enrichment of * oxygen from feed gases from blast furnaces, packaging or Rooms for storing fruits or vegetables and the like.) «Used will.

These materials can also Austausehern for mediginisc uses are cially during artificial Lun, on the one hand due to the Tatsaeh © ₀ • elastomers used telne ¥ © rbiEdung contains "d @ r <sa brin supply with the blood adversely we © (especially the vulcanized composition, " which contains a trace of catalyst" and

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on the other hand due to their asymmetrical structure, in which one of the surfaces with masehen due to the material Has relief, wherein this relief can cause turbulence that the exchange processes between the blood and the gas medium facilitate.

Besides their use for the formation of artificial lungs, the materials according to the invention can also be used for other medical purposes, such as, for example "implantable separating film, as a protective coating for burns and transfer barriers for gases, with sterility between the liquid phase and gas phase is preserved.

The following examples illustrate the invention without restricting it.

example 1

The device used is that shown schematically in FIG.

The organopolysiloxane composition contains:

a ^ -dihydroxy-dimethylpolysiloxane oil

with a viscosity of 5000 cSt at 25 ° C 100 parts by weight

Pyrogenically obtained silica with a large specific surface, that with octamethylcyclotetraslloxane was treated (particle diameter 10 to 40 πιμ) 20 parts by weight

Methyltriacetoxysilane J5 parts by weight

The mesh material is a square mesh fabric Made of polyethylene glycol terephthalate, the properties of which are as follows:

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Yarn; 33 den, 11 single threads, twist: 20 twists per m, not drawn

Number of threads per cm: 9

Thickness of the fabric: 180 - 230 μ

Weight per m ² : 29 g

This tissue was previously freed from oil with ether.

The preparation of the Materialien.wird in a room at 25 ⁰ C is performed, the moisture content is about 5Q.

^ The composition was made under an anhydrous atmosphere in a Vessel 1, which is connected to a pouring device 4, is introduced .

Moving the piston 3 under the action of compressed air (pressure: 1.7 bar) leads the composition through the mouthpiece of the pouring device 4, the distance between which is set to 1 cm and the width of which is set to 20 cm. The composition is applied to the working pad 8, which consists of a polyethylene film with a thickness of 200 μ.

The output of the composition is about 1200 g / h.

The distance between the mouthpiece of the pouring device and the polyethylene film is about 125 μ.

The running speed of the polyethylene film is about 0.5 m / min .

The drum 9 is arranged at a distance of 75 cm from the drum 5 , which corresponds to a dwell time of the film made of Ela.stomerem in a moist atmosphere of about 1 minute and 30 seconds ,

The fabric 11 is applied to the elastomeric film in the manner shown, and a moment of resistance is applied to the drum 10 such that the fabric penetrates

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is effected in the elastomer, which corresponds to a pressure of 0.2 bar.

The overall arrangement of the composite material / polyethylene film is shown in the leave moist environment, and then rolled up after about 20 minutes. ·

After vulcanization is complete (1 1/2 to 2 hours), the polyethylene film is removed from the overall arrangement of organosilicon elastomers and tissue severed.

The total thickness of the composite material is about 280 μ.

Cut out 10 samples from the material, on which you can use the Measures permeability for carbon dioxide and oxygen.

One can determine the permeability of a membrane for a given gas as the amount of gas (in enr under normal temperature and pressure conditions) define that through the membrane per cm of membrane surface and per second for a pressure drop of 1 cm Hg between passes through the upstream and downstream portions of the membrane.

One notes:

P.CO ₂ : 155 x 10 ~ ⁷ to 195 x 10 ~ ⁷ cm ^ / cm ² . see. cm Hg (depending on

the samples)

PO _2: 42nd 10 " ⁷ to 48. 10 ~ ⁷ cm ^ / cm ^2. See. Cm Hg (depending on

the samples).

This permeability corresponds to a non-reinforced elastomer layer of 125 to 143 μ. The selectivity (ratio P CO ₂ / P O ₂ «^ 5) shows that the material is free from perforations.

example 2

The procedure is as in Example 1, except that the fabric made of poly

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ester replaced with a square mesh polyamide fabric having the following properties;

single thread yarn

Number of threads per cm: 100

Diameter of the yarn? ;> 5 M

Thickness of the fabric: 70 μ

Weight each in: 22 g

The total thickness of the composite material is about 140 microns.

The value for the permeability is ₀ 157 for CO. 10 "'cnr / cm, see. Cm Hg.

This permeability corresponds to a non-reinforced elastomer layer with a thickness of 122 to 127 μ.

Example 3

Using the organopolysiloxane composition described in Example 1 and the fabric described in Example 1, a composite material with two elastomer layers is produced here.

The apparatus used is that schematically in Pig. 2 shown. The first layer of the vulcanizable composition is applied with a thickness of 70 μ .. The distance separating the first casting device from the second is 12 m. The running speed of the work pad is 25 cm / min, which corresponds to a dwell time in the Ambient humidity (moisture content: 50; temperature: 25 ⁰ C) corresponds to 48 minutes, during which the vulcanization of the composition proceeds strongly. A second film with a thickness of 70 μ is then poured onto the first film. This second film is exposed to moisture for 1 minute and J> 0 seconds, then the fabric is applied under a pressure of 0.2 bar.

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After the second film has completely vulcanized (approx. 2 hours) the polyethylene working film is separated.

The total thickness of the composite material is 320 Ms; 5050 μ.

The permeability for CO ₂ I is 238. 10 "'cnr / cm. Secern-Hg

for O ₂ : 68. 10 ~ ⁷ cm ^ / cm ² .sec.cm Hg for N ₂ J 29. 10 " ⁷ cni ^ / ^. Sec.cra Hg.

The ratio of permeability COg _{is 4/9} .

Permeability O ₂

The ratio of permeability 0 _{g amounts to 2} ^.

Permeability Ng

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Claims (12)

- 14 -. 2026U79 claims 1. Composite material, which can be used in particular as a membrane, with a total thickness between 120 and 350 μ, consisting of a A film made from an organopolysiloxane elastomer and a material with meshes that can be partially penetrated into one of the surfaces the film is set, characterized in that the elastomer comes from a composition that is at room temperature under the action of water in a liquid or vapor state is vulcanizable, this composition an α, ο-dihydroxylated diorganopolysiloxane oil and a Silane, a polysilane or "a polysiloxane with more than two hydro Contains lyizable groups as crosslinking agents. 2. Material according to claim 1, characterized in that the elastomer further comprises up to 40 percent by "- contains $, based on the total weight of the composition, of fillers in the form of particles, 0.1 does not exceed the maximum diameter u. 2 · Material according to claim 2, characterized in that the Fillers were previously treated with a Qrganopolyslloxan. 4. Material according to one of claims 1 to 3, characterized in that the crosslinking agent is methyltrlacetoxysilane. 5. Material according to one of claims 2 to 4, characterized in that that the filler is pyrogenic silica with a large specific surface. 6. Material according to one of claims 1 to 5 *, characterized in that that the material with mesh is a fabric. 7. Material according to claim 6 _a, characterized in that the fabric consists of polyethylene glycol terephthalate » 10 9 8 13/1771 - 15 - 2Ü26U79 8. Material according to claim 6, characterized in that the fabric consists of polyamide, 9. A method for producing materials according to any one of the claims 1 to 8, characterized in that by pouring on a work pad without adhesiveness forms a film from the vulcanizable composition, this film then moisture stops for a few tens of seconds to a few minutes, a material on the film, the surface of which is still adhesive applies with meshes at a pressure of 0.05 to 0.3 bar, Allows moisture to act on the composite material obtained, until the vulcanization of the organopolysiloxane composition is complete, and finally the material from the working paper separates. " 10. A method for the production of materials according to any one of claims 1 to 8, characterized in that a sheet of elastomer is formed on a work surface, the thickness of which is 50 to 80 % of the thickness that is desired for the organosilicon part of the materials, if this film is exposed to moisture for a few minutes, in order to achieve a partial or complete vulcanization of the film, then one or more of these films Applying layers of the same organopolysiloxane composition and then the material with meshes according to the Method according to claim 9 applies. 11. Use of a composite material according to one of the claims 1 to 8 for the separation of one of the constituents of a mixture which contains oxygen and / or carbon dioxide and / or nitrogen. 12. Use of a composite material according to any one of claims 1 to 8 in a device for carrying out Gas exchange processes with blood is determined. 10 9 8 13/1771