FR3130816A1 - Silicone composition crosslinkable by irradiation - Google Patents

Abstract

The subject of the present invention is a silicone composition X that can be crosslinked by polyaddition reactions to form a silicone elastomer. In particular, the subject of the present invention is a silicone composition X which can be crosslinked by irradiation, and comprising at least one compound D selected from retinol, retinal, retinoic acid, carboxylic acid esters of retinol, carotenes, and their mixtures.

Description

Silicone composition crosslinkable by irradiation

The subject of the present invention is a silicone composition X that can be crosslinked by polyaddition reactions to form a silicone elastomer. In particular, the subject of the present invention is a silicone composition X which can be crosslinked by irradiation, and comprising at least one compound D selected from retinol, retinal, retinoic acid, carboxylic acid esters of retinol, carotenes, and their mixtures.

Technology background

Silicone compositions that can be crosslinked by polyaddition reactions are generally thermally crosslinked in the presence of a platinum catalyst, in particular the Karstedt catalyst. However, for several years, compositions which can be crosslinked by irradiation have been developed. This type of composition which can be crosslinked by irradiation is in particular very useful for “coating” type applications, where a support is covered with a silicone coating. In addition, this type of process has advantages because it consumes less energy than the thermal process, which saves money. This is especially true when the irradiation is carried out by UV-LED systems.

Patent application WO9525734 describes photoactive organoplatinic complexes for crosslinking by hydrosilylation of organopolysiloxane SiH and SiVi. These photoactive organoplatinic complexes are prepared by reacting a photosensitive ligand with the Karstedt complex. However, the systems described in this application do not make it possible to obtain both good reactivity under UV (rapid crosslinking under irradiation), and good stability of the composition without irradiation (long gel time without irradiation).

Document EP0398701 describes silicone compositions comprising a compound having aliphatic unsaturation, a compound containing at least one hydrogen atom bonded to silicon, and a platinum(II) catalyst having β-diketonate ligands, such as Pt(acetylacetonate) ₂ . These compositions are crosslinkable by actinic irradiation. However, these catalysts may exhibit low activity due to limited solubility in silicones.

It is also known to use the Me ₃ Pt(MeCp) complex (platinum trimethyl(methylcyclopentadienyl) complex) as a photocatalyst for hydrosilylation reactions. However, the use of this catalyst has drawbacks because it is volatile, expensive and very toxic.

Moreover, the systems described above are not necessarily usable when the irradiation is carried out by UV-LED systems. Indeed, working with a monochromatic light source such as LEDs requires a more precise design of the photocatalytic system in order to maximize the efficiency of photon absorption, and therefore the reactivity of the system.

It is therefore necessary to develop photocatalytic systems that can overcome these disadvantages.

In this context, the present invention aims to satisfy at least one of the following objectives. One of the objectives of the invention is to provide a composition that can be crosslinked under UV irradiation, and in particular UV-LED.

Another object of the invention is to provide a composition that can be crosslinked under irradiation with good reactivity.

Another object of the invention is to provide a composition that can be crosslinked under irradiation with good stability when it is not irradiated (long gel time without irradiation).

Brief description of the invention

1. au moins un organopolysiloxaneAprésentant, par molécule, au moins deux groupes alcényles en C₂-C₁₂liés au silicium;
2. au moins un organopolysiloxaneBprésentant, par molécule, au moins deux motifs SiH ;
3. une quantité catalytiquement efficace d’au moins un catalyseur d’hydrosilylationC, de préférence un catalyseur d’hydrosilylation à base de platine ; et
4. au moins un composéDsélectionné parmi le rétinol, le rétinal, l’acide rétinoïque, les esters d’acide carboxylique de rétinol, les carotènes, et leurs mélanges.

These objectives, among others, are achieved by the present invention which firstly relates to a silicone composition X crosslinkable by irradiation comprising:

1. at least one organopolysiloxane A having, per molecule, at least two C ₂ -C ₁₂ alkenyl groups bonded to silicon;
2. at least one organopolysiloxane B having, per molecule, at least two SiH units;
3. a catalytically effective amount of at least one C hydrosilylation catalyst, preferably a platinum-based hydrosilylation catalyst; And
4. at least one compound D selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof.

Using a compoundDas defined makes it possible to increase the reactivity of the silicone compositionXunder irradiation, and in particular under UV-LED irradiation. The silicone compositionXcrosshairs faster. Moreover, the compoundDstabilizes the silicone compositionX before irradiation. Thus, it is possible to keep the silicone compositionX non-crosslinked for several hours, when the composition is not subjected to irradiation. Moreover, the compoundDcan be chosen from natural products, which is advantageous.

The present invention also relates to a process for preparing a coating on a support, comprising the following steps:
- application of a silicone composition X on a support, preferably a textile support, and
- crosslinking of said composition by electron or photon irradiation, preferably by exposure to an electron beam, by exposure to gamma rays, or by exposure to radiation with a wavelength of between 100 nm and 450 nm, in particular at UV radiation.

The present invention also relates to a coated support obtainable by said process.

A subject of the present invention is also the use of the silicone composition X for the preparation of silicone elastomers.

A subject of the present invention is also a premix for a silicone composition comprising:
- at least one organopolysiloxane A having, per molecule, at least two C ₂ -C ₁₂ alkenyl groups bonded to silicon,
- at least one hydrosilylation catalyst C , and
- at least one compound D selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof.

Definitions

In the present application, the term "silicone composition crosslinkable by irradiation" means a silicone composition comprising at least one organopolysiloxane capable of hardening by electronic or photonic irradiation. Among the electronic irradiations, we can cite exposure to an electron beam. Among the photon irradiations, mention may be made of exposure to UV radiation or exposure to gamma rays. Preferably, the irradiation is carried out by exposure to radiation with a wavelength of between 100 nm and 450 nm, or between 200 nm and 405 nm.

In this text, "UV" means ultra-violet. Ultraviolet radiation is defined as electromagnetic radiation whose wavelength is between about 100 nm and about 405 nm, i.e. below the visible light spectrum.

In addition, in this text, "LED" is the well-known abbreviation to those skilled in the art for "electroluminescent diode" (also DEL in French).

Unless otherwise indicated, all the viscosities of the silicone oils referred to in this presentation correspond to a magnitude of dynamic viscosity at 25° C. called "Newtonian", that is to say the dynamic viscosity which is measured, in a known per se, with a Brookfield viscometer at a sufficiently low shear rate gradient for the measured viscosity to be independent of the rate gradient.

In the present description, the term "textile" is a generic term encompassing all textile structures. Textiles can be made of yarns, fibers, filaments and/or other materials. They include in particular flexible fabrics, whether woven, glued, knitted, braided, felt, needled, sewn, or made by another method of manufacture. By “yarn”, we mean for example a continuous multifilament object, a continuous yarn obtained by assembling several yarns or a continuous yarn of fibers, obtained from a single type of fiber, or from a mixture of fibers. By "fiber" is meant, for example, a short or long fiber, a fiber intended to be worked in spinning or for the manufacture of nonwoven articles or a tow intended to be cut to form short fibers. The textile may well consist of yarns, fibers and/or filaments having undergone one or more treatment steps before the production of the textile surface, such as, for example, texturing, stretching, stretching-texturing, sizing, relaxation, heat setting, twisting, setting, crimping, washing and/or dyeing.

In the present application, all % and ppm are indicated by weight, unless otherwise indicated.

Claims (12)

Silicone materialXcrosslinkable by irradiation comprising:

1. at least one organopolysiloxane A having, per molecule, at least two C ₂ -C ₁₂ alkenyl groups bonded to silicon;
2. at least one organopolysiloxane B having, per molecule, at least two SiH units;
3. a catalytically effective amount of at least one C hydrosilylation catalyst, preferably a platinum catalyst; And
4. at least one compound D selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof.

Silicone composition X according to Claim 1, characterized in that compound D is of formula (I)

in which R is selected from -CH ₂ OH, -CHO, -COOH, -OCOR', and the following groups:
,
, And
,
with R′ corresponding to a C ₁ to C _{18 ,} preferably C ₁ to C ₆ , alkyl group, and more preferably R′ is a methyl. Silicone composition X according to Claim 1 or 2, characterized in that compound D is β-carotene. Silicone composition X according to one of the preceding claims, characterized in that the molar ratio between the platinum contained in catalyst C and compound D is between 1:1 and 1:250, preferably between 1:5 and 1: 200, and more preferably between 1:10 to 1:100. Silicone composition X according to one of the preceding claims, characterized in that it comprises 2 and 10000 ppm of compound D , preferably between 5 and 1000 ppm, relative to the total weight of the silicone composition X . Silicone X composition according to one of the preceding claims, characterized in that it is crosslinkable by exposure to radiation with a wavelength of between 100 nm and 450 nm, in particular to UV radiation. Silicone composition X according to one of the preceding claims, characterized in that it additionally comprises between 1 and 1000 ppm of a crosslinking inhibitor E , preferably between 2 and 50 ppm, relative to the total weight of the silicone composition X . Process for preparing a coating on a support, comprising the following steps:
- application of a silicone composition X according to any one of claims 1 to 7 on a support, preferably a textile support, and
- crosslinking of said composition by electron or photon irradiation, preferably by exposure to an electron beam, by exposure to gamma rays, or by exposure to radiation with a wavelength of between 100 nm and 450 nm, in particular at UV radiation. Process according to Claim 8, characterized in that the crosslinking takes place by exposure to UV radiation, the source of which is a UV-LED lamp. Coated support obtainable according to the process according to claim 8 or 9. Use of silicone composition X according to any one of Claims 1 to 7, for the preparation of silicone elastomers. Premix for a silicone composition comprising:
- at least one organopolysiloxane A having, per molecule, at least two C ₂ -C ₁₂ alkenyl groups bonded to silicon,
- at least one hydrosilylation catalyst C , and
- at least one compound D selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof.