JP2009506154A - Hydrosilylation process - Google Patents

Abstract

  The present invention relates to a hydrosilylation process comprising mixing an unsaturated base polymer, a silane compound, and a platinum hydrosilylation catalyst comprising a master mixture having solid platinum dispersed in a polymer matrix. The present invention is characterized in that the solid platinum content of the resulting mixture is in the range of 12 ppm to 35 ppm, preferably in the range of 12 ppm to 20 ppm.

Description

  The present invention relates to a hydrosilylation process for preparing a crosslinkable polymer composition in particular.

  A particularly advantageous but non-exhaustive application of the invention is in the field of materials for insulating and / or armoring power and / or telecommunications cables (including fiber optic cables).

  Hydrosilylation is a grafting method that is widely used today, particularly for producing silicones. In general, this consists of grafting a silane compound onto an unsaturated polymer in order to obtain a potentially crosslinkable polymer composition.

  In either case, hydrosilylation is generally performed by mixing an unsaturated polymer and a silane compound in the presence of a platinum-based (ie, main) catalyst (referred to as a platinum-based catalyst). In practice, the polymer is generally used in solid form, while the silane compound and platinum catalyst are usually used in liquid form.

  However, this type of process presents the drawback that it is difficult to move into the cable manufacturing field if the majority of the materials used during compounding are in liquid form. Machines for cable production and in particular extruders are generally made to be suitable for operation with essentially purely solid material being fed.

  Such hydrosilylation processes also have the disadvantage of being very expensive, mainly due to the inherent price of liquid platinum-based catalysts. This is increasingly true since this catalyst must be used in large quantities in order to obtain even uniform results.

  Thus, the technical problem to be solved by the present subject matter is to mix an unsaturated base polymer, a silane compound, and a platinum-based hydrosilylation catalyst comprising a master mixture having solid platinum dispersed in a polymer matrix. A hydrosilylation process comprising, in particular, a good compatibility with the production means of a cable manufacturing plant, making it possible to avoid the problems of the prior art at virtually no cost It is to provide the method.

  According to the invention, a solution to the proposed technical problem consists in bringing the solid platinum content of the mixture obtained by this process in the range of 12 ppm to 35 ppm, preferably in the range of 12 ppm to 20 ppm. .

  It should be understood that the base unsaturated polymer can theoretically be of any known type and in particular can be an olefin. Similarly, the silane compound can very generally be any material containing silicon-hydrogen bonds Si—H.

  The invention thus defined shows the advantage of being perfectly compatible with existing cable manufacturing equipment (especially extruders). In general, when a liquid silane compound is previously mixed with a conventional solid unsaturated polymer, it is possible to achieve mixing with the platinum catalyst while using a completely solid material at the start. The fact that the present invention can be implemented directly using cable production means constitutes an advantage both technically and economically.

  By using the hydrosilylation catalyst in the form of a master mixture, a better dispersion of the platinum in the mixture can also be achieved, thereby achieving a significantly greater effect. Therefore, the same effect can be obtained by using a significantly smaller amount of catalyst, and a significant cost saving can be achieved.

  Another result of reducing the platinum content in the total mixture is that the electrical properties of the final material are maintained. In this case, these characteristics are hardly impaired by the presence of the conductive metal.

  Finally, platinum in the form of a master mixture makes it possible to accurately measure the amount of catalyst actually required. This proves to be fundamental in the scope of the present invention, since the final concentration must be only a few ppm.

  According to a feature of the invention, the polymer matrix of the master mixture is selected from the group consisting of polyolefins, polyolefin copolymers and any mixtures of these components.

  In a particularly advantageous embodiment, the polymer matrix of the master mixture has the same properties as the unsaturated base polymer. This feature can change the mechanical, dielectric and aging properties of the final material.

  According to another characteristic of the invention, the solid platinum of the master mixture consists of hexachloroplatinic acid.

  In a particularly advantageous embodiment, the content of hydrosilylation catalyst is in the range from 4% to 7% with respect to the total amount of unsaturated base polymer.

  According to another characteristic of the invention, the silane compound is a polyhydrosiloxane, in particular polymethylsiloxane.

  According to another advantageous characteristic of the invention, the content of silane compounds is in the range from 1% to 8%, preferably in the range from 4% to 6%, based on the total amount of unsaturated base polymer.

  According to another characteristic of the invention, the crosslinking process is carried out at a temperature in the range from 100 ° C to 125 ° C.

  The present invention also provides any power and / or telecommunications cable having at least one conductor (core) component passed through at least one insulating component, wherein the at least one insulating component performs the hydrosilylation method described above. Also provided are those made from materials that have been cross-linked.

  The present invention also provides any power and / or telecommunications cable with at least one conductor (core) component passed through at least one insulating component, made from a material crosslinked by the hydrosilylation method described above. Also provided is at least one armor provided.

  Other features and advantages of the present invention will become apparent from the following description given by way of non-limiting example.

Preparation of master mixture

  The polymer matrix constituting the master mixture consists in this example of an ethylene-propylene-norbornene terpolymer.

The platinum-based hydrosilylation catalyst has the formula H ₂ PtCl ₆ .xH ₂ O and is in the form of hexachloroplatinic acid containing 41.88% pure platinum element.

  First Preparation A was prepared by adding 1 g of hexachloroplatinic acid to 36 g of polymer (ie, 36 parts by weight of polymer to 1 part by weight of catalyst).

  Specifically, this operation was performed in a closed mixer to ensure good dispersion of the hydrosilylation catalyst within the polymer matrix. The applied temperature was slightly higher than the melting temperature of the ethylene-propylene-norbornene terpolymer (ie 110 ° C.).

  The preparation A thus obtained in this way contained 1.13% pure platinum. Since it is clear that this content is still too high for the intended application, a new dilution operation was performed.

  Thus, a second preparation B was prepared from 1 g of preparation A and 36 g of terpolymer in a proportion similar to that used for the first mixture, ie a ratio of 36 parts by weight of polymer to 1 part by weight of preparation A. .

  This second operation was performed logically using the same conditions as described above. Therefore, for preparation B, an active platinum content of 0.03% was obtained. This advantageously constitutes a master mixture suitable for the present invention, i.e. a master mixture which can be used as a hydrosilylation catalyst.

Preparation of insulating materials

  First, 100 parts by weight of the base polymer was added into a closed mixer maintained at 110 ° C. The base polymer in this example was advantageously the same as that of the master mixture, ie an ethylene-propylene-norbornene terpolymer.

  The above amounts are expressed as parts by weight per 100 parts of base polymer (pph).

  When the polymer melted, the silane compound was added into it. This silane compound was in the form of a mixture of two components. Accordingly, the following was added: first, 3 parts by weight of polymethylhydrosiloxane having -SiH groups in the chain (hereinafter referred to as Silox 1); second, -SiH groups at the end of the chain 3 parts by weight of polymethylhydrosiloxane (hereinafter referred to as Silox 2).

  The hydrosilylation catalyst was then added in the form of a master mixture, in particular in the form of Preparation B, so that the solid platinum content in the resulting mixture was in the range of 12 ppm to 35 ppm, preferably in the range of 12 ppm to 20 ppm. .

  This mixture is hereinafter referred to as the “final mixture”.

  The mixing operation was performed at a temperature of 125 ° C. for 2 minutes.

  Thereafter, after this operation, the final mixture spontaneously cross-linked in ambient air.

  In order to prove that actually good cross-linking was obtained by using the method according to the invention, the measurement of thermal creep under mechanical stress was carried out according to NF standard EN 60811-2-1.

  The thermal creep test consists of placing one end of a dumbbell-type specimen on a weight corresponding to the application of an equal stress of 0.2 MPa and placing the whole in an oven heated to 200 ± 1 ° C. for 15 minutes. .

  If the specimen breaks during the test under the combined action of mechanical stress and temperature, then the result of the test is considered as a failure.

  The creep test was performed on the final composition having the composition detailed in Table 1.

  Final mixtures 1-4 were prepared using the method described above.

  Table 2 gives the thermal creep results in terms of mechanical stress for the final blends 1-4.

  The “days of natural crosslinking” corresponds to the minimum number of days required for the specimen to not break, except when no crosslinking occurs as observed for the specimen of the final mixture 1.

  The test specimen of Final Mix 1 failed the creep test because it broke after being allowed to stand in the oven for 15 minutes after 20 days of spontaneous crosslinking.

  Therefore, the amount of catalyst used of 10 ppm in the final mixture 1 was insufficient to allow the final mixture to have good creep properties.

  Unlike specimens made with final mixture 1, specimens made with final mixture 2 and specimens made with final mixture 3 are very quick and natural in less than 7 days. The crosslinking exhibited very good thermal creep properties under mechanical stress.

  Finally, the specimen made with the final mixture 4 could not be subjected to a creep test for the following reasons. That is, the addition of the catalyst master mixture (0.03% active platinum preparation B) into the hot mixture of unsaturated base polymer and silane compound resulted in a reaction rate that was too fast to control.

  As a result, too many bonds were made for the final mixture to remain deformable.

  Therefore, if mixing was continued, the final mixture was decomposed by breaking the chain, so that mixing could not be continued.

  Therefore, if the solid platinum content is 36 ppm or more, the final mixture becomes unusable and cannot be shaped.

  The invention is not limited to the examples described above, but more generally relates to all methods that can be envisaged based on the general indicators provided in the description of the invention.

Claims (10)

An unsaturated base polymer;
A silane compound;
A platinum hydrosilylation catalyst comprising a master mixture having solid platinum dispersed in a polymer matrix:
In which the solid platinum content of the resulting mixture is in the range of 12 ppm to 35 ppm, preferably in the range of 12 ppm to 20 ppm.   The crosslinking method according to claim 1, characterized in that the polymer matrix of the master mixture is selected from polyolefins and copolymers thereof and any mixture of these components.   The crosslinking method according to claim 1 or 2, wherein the polymer matrix of the master mixture and the unsaturated base polymer are identical.   The crosslinking method according to claim 1, wherein the solid platinum of the master mixture is composed of hexachloroplatinic acid.   The crosslinking method according to any one of claims 1 to 4, wherein the content of the hydrosilylation catalyst is in the range of 4% to 7% with respect to the total amount of the unsaturated base polymer.   The crosslinking method according to claim 1, wherein the silane compound is polyhydrosiloxane.   The content of the silane compound is in the range of 1% to 8%, preferably in the range of 4% to 6%, based on the total amount of the unsaturated base polymer. The crosslinking method as described.   The crosslinking method according to any one of claims 1 to 7, wherein the crosslinking method is performed at a temperature in the range of 100C to 125C.   A cable having at least one conductor component passed through at least one insulation component, wherein the at least one insulation component is made from a material crosslinked using the hydrosilylation method according to any of claims 1-8. The cable described above, wherein   9. At least one armor made of a material cross-linked using the hydrosilylation method according to any of claims 1-8, wherein the cable has at least one conductor component threaded through at least one insulating component. The cable further comprising an accessory.