Method for controlling curing time for silicone gels that release volatile organic substances - Patent Application 20070122999

Abstract

The present invention provides a method for preparing a silicone gel that emits volatile organic substances, comprising the steps of: 2 1) providing a part A comprising 10% to 89.99% by weight of a dihydroxy PDMS polymer having a viscosity measured at 25°C of between 10% and 89.99% by weight of a dihydroxy PDMS polymer and 10% to 90% by weight of a mixture comprising a volatile solvent and a volatile organic material capable of dissolving the dihydroxy polydimethylsiloxane polymer; and 2) providing a part B comprising 10% to 90% by weight of a mixture comprising a volatile solvent and a volatile organic material capable of dissolving (iii) 10% to 30% by weight of MMT and (iv) N-morpholinomethyltriethoxysilane having a viscosity measured at 25°C of between 10 and 245 cSt (mm 2 2) providing a mixture comprising 70% to 90% by weight of a non-functionalized polydimethylsiloxane silicone oil having a viscosity measured at 25°C between 0.15 and 1.5 s ( / s); and 3) providing a mixture comprising 95% to 99% by weight of Part A and 1% to 5% by weight of Part B, wherein Part A also comprises 0.01% to 5% by weight of a carboxylic acid and is free of metal catalysts, as well as a gel obtainable by this method and a kit for carrying out this method.

Description

[Technical Field]

[0001] The present invention relates to the field of articles used to fragrance or deodorize the atmosphere or laundry, or as insect repellents or insecticides, comprising solid polymeric materials containing volatile organic substances. More particularly, the present invention relates to transparent anhydrous silicone gels that diffuse volatile organic substances, which have the advantage of being free of toughening agents and toxic catalysts and having an easily controllable crosslinking time. [Background technology]

[0002] There are many types of devices that emit and / or diffuse volatile organic substances into the environment, such as fragrances, odor-absorbing molecules, or insecticides. These devices can take different forms suited to their use and can be obtained by different techniques. Generally, these products consist of an organic matrix (especially a polymer) of the silicone type.

[0003] A variety of techniques currently exist for producing organic polymer matrices of this type, in particular matrices obtained from silicone elastomers in which one or more volatile organic substances are dispersed.

[0004] A preferred type of silicone elastomer is a cold-vulcanizable silicone elastomer (CVE), formulated from reactive polydimethylsiloxanes (PDMS) with various degrees of polymerization. Crosslinking occurs at room temperature thanks to a crosslinking agent that reacts with the reactive groups in the polysiloxane chain and a catalyst that allows for controlled crosslinking. The elastomers are either one-component (EVF1) or two-component (EVF2, also known as RTV, for "Room Temperature Vulcanization"), in which one of the two parts contains a catalyst. When the product is one-component, the polymerization reaction is activated by contact of the product with atmospheric moisture. When the product is two-component, crosslinking is not activated by atmospheric moisture; it begins when the two components are mixed together.

[0005] Japanese Patent No. 82-40558 describes a method for producing a silicone elastomer matrix intended to diffuse a fragrance into the atmosphere. The silicone elastomer composition is mixed with the fragrance, and then crosslinking of the composition is induced in a mold by adding an organometallic salt. The matrix thus obtained has nonlinear fragrance diffusion due to the incompatibility of the polymer and the fragrance composition.

[0006] EP 2 247 318 describes a transparent anhydrous gel in the form of a crosslinked silicone network containing volatile substances, in particular fragrances, and non-volatile substances, and not containing any fillers or reinforcing agents. The crosslinking of the silicone gel is obtained by the presence of a metal-type catalyst such as tin, titanium, or platinum.

[0007] However, many of these devices have visible drawbacks. For example, the use of catalysts, especially metal catalysts, makes these devices potentially harmful to the environment due to their toxicity. Other devices require fillers or reinforcing agents, which have the drawback of opacifying the gels or increasing their hardness. Certain devices are opaque once formed, making them less attractive to consumers who desire a clear product. For other types of devices, the challenge concerns the amount of volatile organic substances, which is limited and therefore less efficient in space and time. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent No. 82-40558 [Patent Document 2] EP 2 247 318 [Non-patent literature]

[0009] [Non-Patent Document 1] S. Arctander, "Perfume and Flavors" (Montclair, NJ, 1969) [Non-patent document 2] “Common Fragrance and Flavor Materials” Wiley-VCH, Weinheim, 2006 Summary of the Invention [Problem to be solved by the invention]

[0010] The biggest problem manufacturers face is that the silicone-type RTV polymer matrix obtained by mixing two different parts requires a very long crosslinking time when very little crosslinking agent is added, which is difficult to manage on an industrial scale.Today, manufacturers need a technology that allows them to control, and more particularly to accelerate, the crosslinking time of the polymer matrix at will, while using very little crosslinking agent (necessary to obtain a gel that is not opaque and does not emit an unpleasant fishy odor). [Means for solving the problem]

[0011] The present disclosure improves the situation as presented above while solving several technical problems.

[0012] In particular, the Applicant has discovered that the addition of very small amounts of carboxylic acids to two-component systems for producing organic polymer matrices, also referred to hereinafter as silicone gels, makes it possible to control the crosslinking time of said systems.

[0013] Therefore, the present invention relates to a method for preparing a silicone gel that diffuses volatile organic substances, which is prepared using a two-component cold-vulcanizable silicone elastomer that does not contain a metal catalyst and whose crosslinking time can be controlled.

[0014] More precisely, the first subject of the present invention is a method for preparing a silicone gel that diffuses volatile organic substances, comprising the following steps: 1) (i) 3000 to 100,000 cSt (mm 2 providing a part A comprising (i) 10% to 89.99% by weight of a dihydroxy PDMS polymer having a viscosity measured at 25°C of between 10% and 89.99% by weight of a volatile solvent and a volatile organic substance capable of dissolving the dihydroxy PDMS polymer; 2) (iii) 10% to 30% by mass of MMT, and (iv) 10 to 245 cSt (mm 2 providing a Part B comprising 70% to 90% by weight of a non-functionalized PDMS silicone oil having a viscosity measured at 25°C between 100°C and 150°C / sec; 3) preparing a mixture comprising 95% to 99% by weight of Part A and 1% to 5% by weight of Part B; wherein Part A also contains 0.01% to 5% by weight of a carboxylic acid and is free of any metal catalyst.

[0015] A second subject of the invention relates to a silicone gel obtainable via the method that is the subject of the invention, characterized in that it does not contain any metal catalyst.

[0016] A third object of the present invention relates to the use of carboxylic acids in a process for preparing a silicone gel that diffuses volatile organic substances from a two-component cold-vulcanizable silicone elastomer to control the crosslinking time of said elastomer.

[0017] A fourth subject of the invention is a kit for carrying out the method according to the invention, comprising: - (i) 3000 to 100,000 cSt (mm 2 Part A comprising 10% to 89.99% by weight of a dihydroxy PDMS polymer having a viscosity measured at 25°C of between 1 / sec (1 / sec) and 10% to 90% by weight of a mixture comprising at least one volatile solvent capable of dissolving the dihydroxy PDMS polymer and a volatile organic material; - (iii) 10% to 30% by mass of MMT, and (iv) 10 to 245 cSt (mm 2 Part B comprises 70% to 90% by weight of a non-functionalized PDMS silicone oil having a viscosity measured at 25°C between 1000 and 1500 kJ / sec; and wherein Part A also contains 0.01% to 5% by weight of a carboxylic acid and does not contain any metal catalyst, and Part A and Part B are physically separated from each other.

[0018] Other features, details, and advantages will become apparent from a reading of the following detailed description and an examination of the accompanying drawings. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a graph showing the effect of adding myristic acid on crosslinking time. [Figure 2] 1 is a graph showing the molar ratio of carboxylic acid / N-morpholinomethyltriethoxysilane (MMT). DETAILED DESCRIPTION OF THE INVENTION

[0020] The silicone gel of the present invention that diffuses volatile organic substances is a gel obtained from a room temperature crosslinkable (RTV) two-component system.This system is typically packaged into two completely different and physically separated parts, namely, a part (part A) that contains crosslinkable silicone elastomer and a crosslinked part (part B).The silicone gel is prepared by mixing the two parts together and then forming the gel, for example, in a mold.The crosslinkable silicone composition of the present invention is a functionalized silicone polymer.

[0021] According to the present invention, a silicone gel for diffusing volatile organic substances can be prepared by the following method: 1) (i) 3000 to 100,000 cSt (mm 2providing a Part A comprising (i) 10% to 89.99% by weight of a dihydroxy PDMS polymer having a viscosity measured at 25°C of between 10% and 89.99% by weight of a dihydroxy PDMS polymer having a viscosity measured at 25°C of between 10% and 89.99% by weight of a dihydroxy PDMS polymer; and (ii) 10% to 90% by weight of a mixture comprising a volatile solvent capable of dissolving the dihydroxy PDMS polymer and a volatile organic material; 2) (iii) 10% to 30% by mass of MMT, and (iv) 10 to 245 cSt (mm 2 providing a Part B comprising 70% to 90% by weight of a non-functionalized PDMS silicone oil having a viscosity measured at 25°C between 0.1 V and 1.5 V (1 / sec); 3) preparing a mixture comprising 95% to 99% by weight of Part A and 1% to 5% by weight of Part B; Part A also contains 0.01% to 5% of a carboxylic acid and does not contain any metal catalyst.

[0022] The term "gel" means a homogeneous, elastic, network-forming composition having a relative resistance of less than 20 g / mm, in particular less than 15 g / mm, preferably less than 10 g / mm. The relative resistance of the gel is measured at 25°C using a texturometer.

[0023] For example, a Rheo TA-XT texturometer may be used in "compression force measurement" mode using a 6 mm Stable Micro Systems SMS P / 6 stainless steel cylindrical probe; test speed 0.50 mm / sec; target mode: distance; break mode: rate; and break sensitivity 5.0 g.

[0024] Part A Part A is from 3000 to 100000 cSt (mm 2In the context of the present invention, the functionalized silicone polymer is a polydimethylsiloxane (also known as dihydroxy PDMS) functionalized at both ends with hydroxyl groups, having a viscosity (measured at 25°C) of between 3,000 and 100,000 cSt (mm 2 Their viscosities measured at 25°C are between 3000 and 75000 cSt (mm 2 / sec), 3000 to 50000cSt (mm 2 / sec), 3000 to 35000 cSt (mm 2 / sec), between 3000 and 10000 cSt (mm 2 / sec), between 3000 and 9000 cSt (mm 2 / sec), 4000 to 8000 cSt (mm 2 / sec), 5000 to 7000 cSt (mm 2 Preferentially, the dihydroxy PDMS polymer may have a viscosity of about 6000 cSt (mm 2 / sec), measured at 25°C. 2 The viscosity of dihydroxy PDMS polymer, expressed as kinematic viscosity in Pa·sec (units of Pa·sec), was measured at 25°C using a TA Instruments Discovery HR-2 rheometer and the standard method provided by standard DIN 53019 (2008) (including its calibration), and then converted from viscous to kinematic viscosity by dividing the former by the density of the dihydroxy PDMS polymer.

[0025] An advantage of the present invention over existing systems is that the system does not require the addition of metal catalysts, particularly tin catalysts, to effect crosslinking.

[0026] Part A also contains 10% to 90% by weight of a mixture containing a volatile solvent and a volatile organic material capable of dissolving the dihydroxy PDMS polymer.

[0027] The term "volatile organic substance" means a product containing one or more organic molecules that have a vapor pressure higher than atmospheric pressure at room temperature, i.e. at 25°C. The volatile organic substance used according to the invention may be selected from fragrances, odor masking agents or insecticides. Preferentially, it is a fragrance.

[0028] The fragrance may be selected from a large number of odoriferous compounds. The fragrance according to the present invention may be one or a combination of several odoriferous compounds. Such odoriferous compounds are described, for example, in S. Arctander, "Perfume and Flavors" (Montclair, NJ, 1969) or "Common Fragrance and Flavor Materials", Wiley-VCH, Weinheim, 2006.

[0029] Non-limiting examples of the latter include the following families: aromatic hydrocarbons, terpenes and / or sesquiterpenes, in particular essential oils containing these molecules, in particular citrus oils (lemon, orange, grapefruit, bergamot), nutmeg, etc., aromatic alcohols, in particular benzyl alcohol, phenylethyl alcohol, and phenylpropyl alcohol; Alcohols, in particular cyclic or acyclic, saturated or unsaturated, primary, secondary or tertiary non-aromatic linalool, citronellol, geraniol, nerol, dihydromyrcenol, terpineol and aliphatic alicyclic alcohols containing from 4 to 10 carbon atoms in the chain, Aldehydes, in particular saturated and unsaturated alicyclic aliphatic aldehydes whose carbon chains contain from 4 to 12 carbon atoms, aromatic aldehydes such as cinnamaldehyde, alpha-amyl cinnamaldehyde, and alpha-hexyl cinnamaldehyde, aromatic aldehydes, lilial and phenolic aldehydes such as vanillin and ethyl vanillin, Phenols, especially aromatic phenols, such as eugenol and isoeugenol, and the related methyl ethers; carboxylic acid esters, in particular acetates of benzyl alcohol, geraniol, citronellol, nerol, terpineol, borneol or linalool, Aromatic acid esters, such as benzoates and salicylates, but also cinnamates, esterified with alcohols of the aliphatic series containing a chain of 1 to 6 carbon atoms; Aromatic phenolic acids, mainly their aromatic lactone forms, such as coumarin and dihydrocoumarin, alcoholic carboxylic acids in their lactone form and dodeca-lactones, more particularly octa-, undeca- and gamma-dodeca-lactone, delta-deca-lactone, delta-undeca-lactone and delta-lactone, in their saturated or unsaturated form; Macrocyclic compounds, the carbon chain of which contains 12 to 16 carbon atoms; ethers and acetals in their acyclic or cyclic form, in particular aromatic and non-aromatic aldehyde acetals containing a carbon chain of 4 to 10 carbon atoms, also substituted furfuran cyclic ethers and substituted or unsubstituted pyran cyclic ethers; Heterocyclic compounds containing one nitrogen atom, in particular indole derivatives, and also heterocyclic compounds containing two nitrogen atoms, in particular those of the pyrazine series, ketones, in particular aromatic ketones, such as 4-(p-hydroxyphenyl)-2-butanone, and cyclic or acyclic, saturated or unsaturated non-aromatic ketones, in particular those of the pyrazine series; Aromatic or non-aromatic sulfides, disulfides, and mercaptans It is a compound belonging to the

[0030] The term "odor masking agent" or "odor neutralizer" means an agent capable of reducing or eliminating the perception of a malodor generated by one or more molecules contained in the composition of a product.

[0031] The odor masking agents may be selected from a) monoesters; b) di- and / or tri-esters; c) alcohols, advantageously monoalcohols containing from 1 to 30 carbon atoms, which carbon atoms form a linear or branched chain, optionally containing one or more unsaturations in the form of double bonds, and optionally containing saturated or fully or partially unsaturated 5- or 6-membered ring structures; d) aldehydes and / or ketones, in particular aldehydes and / or ketones of the formula R-CO-Rb, where R represents a linear or branched hydrocarbon-based chain containing from 1 to 6 carbon atoms and optionally containing one or more unsaturations in the form of double bonds, and R represents a hydrogen atom, a cyclic hydrocarbon-based chain, or a linear or branched hydrocarbon-based chain, optionally but preferably substituted with a cyclic structure, and R contains from 6 to 12 carbon atoms and optionally containing one or more unsaturations in the form of double bonds, and optionally substituted with one or more hydroxyl groups; and e) terpenes.

[0032] The term "insecticide" means an active substance or preparation that has the property of killing insects, especially mosquitoes, or other invertebrates (mites, myriapods). Insecticides may be obtained by chemical synthesis or may be of plant origin. In the context of the present invention, the insecticide is of plant origin. It may be selected from limonene or geraniol.

[0033] The concentration of volatile organic substances in the volatile solvent may range from 0.05% to 50% by weight, in particular from 1% to 45% by weight, in particular from 2% to 40% by weight, in particular from 3% to 35% by weight, in particular from 5% to 30% by weight, or in particular from 10% to 45% by weight, in particular from 15% to 40% by weight, in particular from 20% to 35% by weight, based on the total weight of part A.

[0034] The volatile solvent according to the present invention may be selected from a number of solvents, and may be one or a combination of several solvents. Preferably, the volatile solvent is odorless or has only a slight odor. In all cases, the volatile solvent must be capable of dissolving dihydroxy PDMS.

[0035] In a first embodiment of the present invention, the volatile solvent capable of dissolving dihydroxy PDMS is selected from non-polar solvents such as C7-C12 isoparaffins, and the silicones are hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and hexane. Commercial examples of volatile isoparaffins are Isopar C® to Isopar P® from Exxon Chemical, which have flash points between 40 and 100°C. Preferentially, the volatile solvent is a C10-12 isoparaffin.

[0036] In a second embodiment of the present invention, the volatile solvent capable of dissolving dihydroxy PDMS is selected from low molecular weight alkanes and sparingly polar solvents, such as fatty acid esters such as isopropyl myristate, butyl myristate, isobutyl oleate, isopropyl oleate, and diisopropyl adipate.

[0037] Furthermore, part A of the system contains carboxylic acids in an amount of 0.01% to 5% by weight, in particular 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22% , 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.50%, 1%, 1.50%, 2%, 2.50%, 3%, 3.50%, 4%, 4.50%, or 5%.

[0038] Carboxylic acids allow the crosslinking time of silicone elastomers to be controlled by adjusting the amount of carboxylic acid used. The more acid, the shorter the crosslinking time. Thus, carboxylic acids accelerate the crosslinking time of silicone elastomers.

[0039] The carboxylic acid is in particular of formula (I):

[0040] [ka]

[0041] (wherein R represents hydrogen, linear or branched C1 to C17 alkyl, linear or branched C5 to C17 alkenyl, particularly branched C4 to C5 alkenyl, or a phenyl group) The carboxylic acids are selected from the group consisting of:

[0042] The carboxylic acid may be selected from stearic acid, oleic acid, palmitic acid, myristic acid, lauric acid, undecylenic acid, capric acid, methyl-2-pentenoate, acetic acid, formic acid, isovaleric acid, methyl-2-butyric acid, or phenylacetic acid.

[0043] In a preferred embodiment, the carboxylic acid is myristic acid.

[0044] In a preferred embodiment, the carboxylic acid is present between 0.02% and 1% by weight, relative to the weight of part A. In an even more preferred embodiment, the carboxylic acid is present between 0.05% and 0.5% by weight, relative to the weight of part A.

[0045] Part B Part B of the system contains 10% to 30% N-morpholinomethyl-triethoxysilane (MMT). This compound acts as a crosslinker in the system. This crosslinker has a viscosity of 10 to 245 cSt (mm) that is capable of dissolving the MMT. 2 / sec) (measured at 25°C) diluted in a solvent consisting of non-functionalized PDMS silicone oil.2 The viscosity of the non-functionalized PDMS silicone oil, expressed as a dynamic viscosity in Pa·sec, is measured at 25°C using a TA Instruments Discovery HR-2 rheometer and the standard method provided by standard DIN 53019 (2008) (including its calibration), and then converted from a dynamic viscosity to a dynamic viscosity by dividing the first value by the density of the non-functionalized PDMS silicone oil. The solvent is present in an amount between 70% and 90% of Part B, for that part.

[0046] Preferentially, non-functionalized PDMS silicone oil has a viscosity of 10 cSt (mm 2 / sec) measured at 25°C.

[0047] The applicant has found that there is an advantageous molar ratio between the amount of carboxylic acid and the amount of MMT used in the method of the present invention. This advantageous molar ratio between the amount of carboxylic acid and the amount of MMT is between 0.1 and 1. In a specific embodiment of the present invention, the ratio between the amount of carboxylic acid and the amount of MMT is between 0.1 and 1. A ratio greater than 0.1 makes it possible to obtain a good crosslinking time, i.e., less than 2 hours, without using too much carboxylic acid. When the ratio is greater than 1, the addition of carboxylic acid does not significantly affect the crosslinking time.

[0048] A second subject relates to the silicone gel obtainable via the process that is the subject of the present invention, characterized in that it does not contain any metal catalyst.

[0049] The gel according to the present invention is characterized by allowing the diffusion of volatile organic substances, i.e., controlled release in time and space.Therefore, the gel can be used to scent or deodorize the atmosphere, linen, or as an insect repellent or insecticide.Preferably, the gel is used to scent the atmosphere.When used as a scent or deodorizing product, the silicone gel can be used in any type of environment, especially in homes, commercial or industrial facilities, or in cars.

[0050] The silicone gel according to the invention is characterized by the advantage that it is transparent.

[0051] The term "transparent" means that the gel has a haze of less than 40 NTU (Nephelometric Turbidity Units) at 25°C as measured using a turbidimeter. The term "transparent" according to the present invention does not mean "colorless". Thus, a transparent gel may also be a transparent colored gel.

[0052] In a preferred embodiment of the present invention, the gel haze is less than 20 NTU, more preferably less than 12 NTU, and most preferably less than 8 NTU. NTU (Nephelometric Turbidity Units) is the unit used to describe haze. The greater the diffusion, the higher the haze. Consequently, a low NTU value indicates high transparency, while a high NTU value indicates low transparency. The turbidimeter measurement process is based on a comparison of the intensity of light scattered by a sample under defined conditions to the intensity of light scattered by a standard reference suspension, which is normally haze-free water (distilled water or distilled water passed through a 0.45 μm membrane filter). The turbidimeter will consist of a nephelometer with a light source that allows illumination of the sample, and one or more photoelectron detectors with a readout device that indicates the intensity of light scattered perpendicular to the incident light path. The turbidimeter must be designed so that little stray light reaches the detector in the absence of haze and should exhibit no significant drift after a short heating period.

[0053] The Hach Turbidimeter Models 2100 and 2100 A are widely used and have proven to be reliable; however, other instruments that meet the above design criteria are acceptable, such as the Turbi-direct® machines sold by Aqua lytique.

[0054] Advantageously, the silicone gel according to the invention does not contain any toughening agents.

[0055] Advantageously, the silicone gel according to the invention has a relative resistance of less than 20 g / mm.

[0056] Furthermore, the gel according to the invention is anhydrous. The term "anhydrous" means "containing no water", i.e. a gel in which no water is present in the form of hydrates or water of crystallization.

[0057] A third object of the present invention relates to the use of carboxylic acids in a process for preparing a silicone gel that diffuses volatile organic substances from a two-component cold-vulcanizable silicone elastomer to control the crosslinking time of said elastomer.

[0058] Carboxylic acids not only allow the crosslinking time to be controlled, but more particularly, the crosslinking time of the elastomer can be accelerated in a controlled manner.

[0059] The carboxylic acids that can be used in the present invention are represented by the general formula (I)

[0060] [ka]

[0061] (wherein R represents hydrogen, linear or branched C1 to C17 alkyl, linear or branched C5 to C17 alkenyl, particularly branched C4 to C5 alkenyl, or a phenyl group) It has.

[0062] In a preferred embodiment, the carboxylic acid used is selected from stearic acid, oleic acid, palmitic acid, myristic acid, lauric acid, undecylenic acid, capric acid, methyl-2-pentenoic acid, acetic acid, formic acid, isovaleric acid, methyl-2-butyric acid, and phenylacetic acid. Preferentially, the carboxylic acid is myristic acid.

[0063] A fourth subject of the invention is a kit for carrying out the method according to the invention, comprising: - (i) 3000 to 100,000 cSt (mm 2Part A comprising 10% to 89.99% by weight of a dihydroxy PDMS polymer having a viscosity measured at 25°C of between 10% and 89.99% by weight of a volatile solvent and a volatile organic substance capable of dissolving the dihydroxy PDMS polymer; - (iii) 10% to 30% by mass of MMT, and (iv) 10 to 245 cSt (mm 2 Part B comprises 70% to 90% by weight of a non-functionalized PDMS silicone oil having a viscosity measured at 25°C of between 1 / sec and 2 / sec; wherein Part A also contains 0.01% to 5% by weight of a carboxylic acid and does not contain any metal catalyst, and Part A and Part B are physically separate from each other.

[0064] In the kit, parts A and B are as previously defined.

[0065] The present invention is hereinafter illustrated by the following examples, which should not be considered as limiting the scope of the invention and which should be read in conjunction with the figures. [Example]

[0066] Example 1 Part A Composition (Silicone Matrix): Dihydroxy PDMS (polymer purchased from Wacker®, trade name FD6 6000 cSt (mm 2 / sec))=60g(60% by mass) Air freshener = 30g (30% by mass) Isopar L(Exxon)=4.6g(4.6% by mass) Isopar M(Exxon)=5g(5% by mass) Myristic acid (MA) = 0.4g (0.4% by mass) The preferred percentage of myristic acid is 0.4% by weight, although this amount may vary as a function of the fragrance used and the desired crosslinking time.

[0067] Example 2 Composition of Part B (Crosslinker): Silicone oil 10cSt(mm 2 / sec)=85% by mass MMT ((N-morpholinomethyl)triethoxysilane) CAS# 21743-27-1 = 15% by mass This crosslinker solution is purchased from Wacker® under the name HC1015 and is used as is.

[0068] Example 3 Aromatic silicone gel Part A according to Example 1 = 97% by weight Part B according to Example 2 = 3% by weight Add Part B (crosslinker) to Part A and mix until a homogeneous mixture is obtained. Pour the mixture into glass or PET containers, close, and allow to gel.

[0069] Example 4 Behavior of various acids To demonstrate the similar effects of various carboxylic acids, several silicone gels were prepared with the same molar amount of acid. Gels were prepared according to the formula and method set forth in Example 3. To prepare these gels, the fragrance described in Example 1 was replaced with an equal amount of Isopar L. Approximately 1 g of this mixture was then placed in a rheometer to measure the crosslinking time.

[0070] Procedure for measuring crosslinking time The crosslinking time is measured using a TA-Instruments Discovery HR-2 rheometer. The measurement is performed in oscillation time mode, and the crosslinking time is obtained at the intersection of the elastic modulus with the G' and G" loss moduli.

[0071] The rheometer measurement protocol is described below: - Geometry: 40.0mm 3.9875° Cone Plate - Mode: Oscillation Time - Temperature: 25℃ - Sampling interval: 30.0 seconds / pt - Stress: 1% - Frequency: 1Hz - Gap: 110 μm

[0072] [Table 1]

[0073] This example highlights the fact that a variety of carboxylic acids of different chain lengths can be used to reduce crosslinking times. Furthermore, it is found that the chain length of the carboxylic acid used does not affect the crosslinking time.

[0074] Example 5 Control of crosslinking time To highlight the possibility of controlling the crosslinking time by adding very small amounts of carboxylic acid, several gels with different amounts of myristic acid were prepared. The gels were prepared according to the formula and method set forth in Example 3. To prepare these gels, the fragrance described in Example 1 was replaced with an equal amount of Isopar L. Approximately 1 g of this mixture was then placed in the rheometer and crosslinking time measurements were performed as described above.

[0075] To highlight the possibility of controlling the crosslinking time by adding very small amounts of myristic acid.

[0076] [Table 2]

[0077] As shown in Table 2 and also in Figure 1, adding very small amounts of myristic acid shortens the crosslinking time of the silicone matrix + crosslinker mixture (Part A + Part B). The more acid added, the shorter the crosslinking time. Therefore, the user can control the crosslinking time by adjusting the amount of acid (in this case, myristic acid) added.

[0078] Figure 2 shows the molar ratio (r) = n acids / n MMT. The graph shown in Figure 2 is advantageous when it is desired to know how much of a given carboxylic acid must be used to obtain a desired crosslinking time.

[0079] Example 6 Cure times for fragrance formulations To highlight the fact that crosslinking time can be controlled when using different fragrance compositions, several gels were prepared according to the formulation given in Example 3.

[0080] [Table 3]

[0081] As this table shows, the addition of carboxylic acid significantly reduces the crosslinking time of the fragrance gels described in Table 3.

Claims

1. 1. A method for preparing a silicone gel that diffuses volatile organic substances, comprising the steps of: 1) (i) 3,000 to 100,000 mm ２ 10% to 89.99% by weight of a dihydroxypolydimethylsiloxane polymer having a viscosity measured at 25°C of between 1 / 2 and 1 / 2 second; and (ii) a volatile solvent capable of dissolving the dihydroxypolydimethylsiloxane polymer, and - Volatile organic substances providing Part A comprising 10% to 90% by weight of a mixture comprising: 2) (iii) 10% to 30% by weight of N-morpholinomethyltriethoxysilane, and (iv) a 10 to 245 mm crystalline silica capable of dissolving N-morpholinomethyltriethoxysilane. ２ providing a Part B comprising 70% to 90% by weight of a non-functionalized polydimethylsiloxane silicone oil having a viscosity measured at 25°C of between 1 / 2 and 1 / 4 second; 3) preparing a mixture comprising 95% to 99% by weight of Part A and 1% to 5% by weight of Part B; wherein Part A also comprises 0.01% to 5% by weight of a carboxylic acid and is free of any metal catalyst.

2. The carboxylic acid is represented by the following general formula (I): 【Chemistry 1】 (wherein R represents hydrogen, linear or branched C1 to C17 alkyl, linear or branched C5 to C17 alkenyl, particularly branched C4 to C5 alkenyl, or a phenyl group).

2. The method of claim 1, comprising:

3. 3. The method according to claim 1 or 2, characterized in that the carboxylic acid is selected from stearic acid, oleic acid, palmitic acid, myristic acid, lauric acid, undecylenic acid, capric acid, methyl-2-pentenoic acid, acetic acid, formic acid, isovaleric acid, methyl-2-butyric acid, or phenylacetic acid.

4. 4. The method according to claim 1, wherein the carboxylic acid is myristic acid.

5. 5. The process according to claim 1, wherein the carboxylic acid is present in an amount of between 0.02% and 1% by weight relative to the total weight of part A.

6. The dihydroxypolydimethylsiloxane has a viscosity of 4000 to 8000 mm ２ 6. The method according to claim 1, wherein the viscosity measured at 25°C is between 0.1 and 1.0 s. / s.

7. 7. The method according to any one of claims 1 to 6, characterized in that the volatile organic substance is selected from a fragrance, an odor masking agent, or an insecticide.

8. 8. The method according to claim 1, wherein the concentration of the volatile organic substances in the volatile solvent is from 0.05% to 50% by weight, in particular from 5% to 30% by weight, relative to the total weight of part A.

9. 9. The method according to claim 1, wherein the volatile solvent capable of dissolving dihydroxypolydimethylsiloxane is selected from non-polar solvents such as C7 to C12 isoparaffins, and the silicone is hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, docomethylcyclohexasiloxane, and hexane.

10. 9. The method according to claim 1, wherein the volatile solvent capable of dissolving dihydroxypolydimethylsiloxane is selected from low molecular weight alkanes and low polarity solvents, for example fatty acid esters such as isopropyl myristate, butyl myristate, isobutyl oleate, isopropyl oleate, and diisopropyl adipate.

11. 10. The method of claim 9, wherein the volatile solvent is a C10-C12 isoparaffin.

12. 12. The method according to any one of claims 1 to 11, characterized in that the molar ratio between the amount of carboxylic acid and the amount of N-morpholinomethyltriethoxysilane is between 0.1 and 1.

13. A silicone gel for diffusing volatile organic substances obtainable via the method according to any one of claims 1 to 12, characterized in that it does not contain any metal catalyst.

14. The silicone gel for diffusing volatile organic substances according to claim 13, characterized in that it is transparent.

15. 15. A silicone gel for diffusing volatile organic substances according to claim 13 or 14, characterized in that it does not contain any reinforcing agent.

16. 16. A silicone gel for diffusing volatile organic substances according to any one of claims 13 to 15, characterized in that it has a relative resistance of less than 20 g / mm.

17. 1. A method for preparing a silicone gel that diffuses volatile organic substances from a two-component cold-vulcanizable silicone elastomer, using a carboxylic acid to control the crosslinking time of the elastomer.

18. 18. Use according to claim 17 for accelerating the crosslinking time of said elastomer in a controlled manner.

19. The carboxylic acid is represented by the following general formula (I): 【Chemistry 2】 (wherein R represents hydrogen, linear or branched C1 to C17 alkyl, linear or branched C5 to C17 alkenyl, particularly branched C4 to C5 alkenyl, or a phenyl group).

19. Use according to claim 17 or 18, characterized in that it has

20. 20. Use according to any one of claims 17 to 19, characterized in that the carboxylic acid is selected from stearic acid, oleic acid, palmitic acid, myristic acid, lauric acid, undecylenic acid, capric acid, methyl-2-pentenoate, acetic acid, formic acid, isovaleric acid, methyl-2-butyric acid, or phenylacetic acid.

21. 21. Use according to any one of claims 17 to 20, characterized in that the carboxylic acid is myristic acid.

22. A kit for carrying out the method of any one of claims 1 to 12, comprising: (i) 3,000 to 100,000 mm ２ Part A comprising: (i) 10% to 89.99% by weight of a dihydroxypolydimethylsiloxane polymer having a viscosity measured at 25°C of between 1 / 2 s and 1 / 2 s; and (ii) 10% to 90% by weight of a mixture comprising at least one volatile solvent capable of dissolving the dihydroxypolydimethylsiloxane polymer and a volatile organic material; (iii) 10% to 30% by weight of N-morpholinomethyltriethoxysilane, and (iv) a 10 to 245 mm solubility solvent capable of dissolving N-morpholinomethyltriethoxysilane. ２ Part B comprising 70% to 90% by weight of a non-functionalized polydimethylsiloxane silicone oil having a viscosity measured at 25°C of between 1 / 2 second and 1 / 3 second; wherein Part A also contains 0.01% to 5% by weight of a carboxylic acid and does not contain any metal catalyst, and wherein Part A and Part B are physically separated from each other.

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