MXPA99011628A - Coated air sacks, covering material and coating process - Google Patents

Abstract

Aqueous emulsions, characterized in that they contain organopolysiloxanes which have in the terminal units groups linked to SiC with multiple aliphatic bonds, organopolysiloxanes possessing at least 3 hydrogen atoms attached to Si, a catalyst that promotes the addition of hydrogen bound to Si to the multiple aliphatic bonds, organic silicon compounds suitable as adhesion promoters, desilicone resins, emulsifier, water and carbon black

Description

SACKS OF AIR COVERED. COATING MATERIAL AND COATING PROCESS The invention relates to aqueous emulsions, a process for their preparation, compositions that can be prepared using these aqueous emulsions, a process for coating organic fibers using aqueous emulsions of this kind and textile substrates coated with these emulsions. EP-A 758666 discloses aqueous emulsions containing addition-crosslinkable organopolysiloxanes, which are used for the coating of airbag fabrics. However, these have the drawback that the combustion rate in the horizontal combustion test according to FMUSS 302 or 208 is too high. It is an object of the invention to solve the drawbacks of the prior art and particularly to provide aqueous emulsions which coat a textile product, result in a moderate combustion behavior, particularly in the case of airbags, additionally have a low coating weight and improved adhesion of coating and provide an improved value in the washing test (Scrub Test) according to ISO 5981, and make possible an economical coating process. Object of the invention are aqueous emulsions, which are characterized in that they contain (1) organopolysiloxanes which have in the terminal units groups linked to SiC with multiple aliphatic bonds, (2) organopolysiloxanes possessing at least 3 hydrogen atoms attached to Si, (3) ) catalyst that promotes the addition of hydrogen bound to Si to multiple aliphatic bonds, (4) organic silicon compounds suitable as adhesion promoters, (5) silicone resins, (6) emulsifier, (7) water and (8) Carbon black In the case of groups with multiple aliphatic bonds, these are preferably vinyl groups or allyl groups, with vinyl groups being particularly preferred. In the case of the diorganopolysiloxanes (1) having in the terminal units groups linked to SiC with multiple aliphatic bonds corresponding to the invention, it is preferably any diorganopolysiloxanes with vinyl groups in the terminal units, preferably compounds of this type of the formula general (CH2 = CH) xSiR3.xO (S¡R2O) nSiR3.x (CH = CH2) x in which R means the same or different hydrocarbon radicals preferably having 1 to 18 carbon atom (s), which may be substituted and X is 1, 2 or 3, preferably 1 and n is an integer with a value such that the diorganopolysiloxanes (1) preferably have an average viscosity of 100-500,000 mPa-s at 25 ° C. A range of 200-200,000 mPa-s at 25 ° C and particularly preferably a range of 500-100,000 mPa-s at 25 ° C is preferred. Examples of hydrocarbon radicals R are preferably alkyl radicals, such as methyl, ethyl, n-propyl, isopropyl, butyl, octyl, tetradecyl or octadecyl radicals; hydrocarbon cycloaliphatic radicals, such as the cyclopentyl, cyclohexyl or methylcyclohexyl radicals; aryl radicals, such as the phenyl radical; alkaryl radicals, such as tolyl radicals; and aralkyl radicals, such as the benzyl radical or the phenyl-ethyl radical. Examples of substituted hydrocarbon radicals which may be mentioned are halogenated radicals, such as the 3,3,3-trifluoropropyl, 3-chloropropyl or chlorophenyl radicals. Cyanoalkyl radicals, such as the cyanoethyl radical, may also be present. Also, radicals with unsaturated aliphatic groups, such as preferably the vinyl, allyl, hexenyl or cyclohexenyl radicals, may be contained. As radicals R, hydrocarbon radicals with 1-10 carbon atom (s) are preferred, in which it is particularly preferred that at least 80% of the organic radicals designated as R are preferably methyl radicals. In the case of the organopolysiloxanes mentioned, they may be identical copolymers or mixtures of different copolymers with a degree of polymerization identical in each case or with different degrees of polymerization. When diorganopolysiloxanes contain different diorganopolysiloxane units, there may be a statistical distribution or a distribution of blocks. In the product according to the invention, the diorganopolysiloxane (1) is preferably contained in amounts of 10-80% by weight, more preferably in quantities of 20-60% by weight, and particularly preferably in amounts of 20 to 60% by weight. 50% by weight. Organopolysiloxanes (2) having at least 3 hydrogen atoms attached to Si are preferably compounds of this type of the formula (CH3) 3S¡O- (S¡HRO) or- (SiR2O) p-Si (CH3) 3, wherein R can have the meaning mentioned above and o / p is preferably present in the ratio 1: 0 to 1: 20, more preferably 1: 0 to 1: 7. The sum of o and p may preferably be between 10 and 1000, more preferably between 20 and 200, and still more preferably between 30 and 100.

Equal or different organopolysiloxane molecules (2) can be used. In organopolysiloxanes having at least 3 hydrogen atoms attached to Si per molecule, the unsaturated silicon valences with hydrogen and oxygen atoms of the siloxane are preferably saturated by methyl, ethyl or phenyl radicals. However, all the radicals described above can also be contained as R. In the product according to the invention, the organopolysiloxane (2) is preferably contained in amounts of 1-40% by weight, more preferably in amounts of 2 - 20% by weight, and especially preferably in amounts of 3-15% by weight. As catalysts (3) that promote the addition of hydrogen bound to Si to the multiple aliphatic bonds, any catalysts known to promote this reaction can be employed. Examples of catalysts of this class are preferably finely divided metal platinum (Platinsol), ruthenium, rhodium, palladium or iridium. These metals can be applied on solid supports, such as silicon dioxide, aluminum oxide or activated carbon, ceramic materials or mixed oxides or mixed hydroxides. Even compounds or complexes of these metals such as PtCI4, H2PtCl6.6H2O; Na2PtCl4.4H2O, platinum-olefin complexes, platinum-alcohol complexes, such as Speyers catalyst, platinum-alcoholate complexes, platinum-ether complexes, platinum-aldehyde complexes, platinum-ketone complexes, such as reaction products of cyclohexanone and hexachloroplatinic acid , platinum-vinylsiloxane complexes, particularly platinum-divinyltetramethyldisiloxane complexes with or without organically combined halogen content, bis- (gamma-picolin) -platinum dichloride, trimethylenepyridinplatinum dichloride, dicyclopentadienoplatinum dichloride, dimethylsulfoxydiethylene dichloride (2), and the products of reaction of platinum tetrachloride dissolved in 1-octene with sec-butylamine. In the product according to the invention, platinum compounds are preferred as catalysts. Mixtures of catalysts can be used, but also a single class of the catalysts mentioned above. In the product according to the invention, amounts of catalysts can be used such that in the case of platinum catalysts the content of platinum in the mixture according to the invention is preferably between 3 and 500 ppm, based on the siloxane content. Preferably, a platinum content of 10-200 ppm is used, based on the polysiloxanes used. For the preparation of aqueous emulsions, any adhesion promoters can be used. As an example of the organosilicon compounds (4) suitable as adhesion promoters, preferably silanes with hydrolysable radicals and vinyol, acryloxy, methacryloxy, epoxy or acid anhydride groups bonded to the silicon are used via carbon. Partial hydrolysates and / or mixed hydrolysates of silanes of this type can also be used.

Preferably a reaction product of vinyltriacetoxysilane and the silane of the formula is employed H H HC-C- -CH2- 0- CH2- CH2- CH2 - Si (0CH3) 3 O A single class of adhesion promoter can be used, but mixtures of two or more silanes or their reaction products, or partial or mixed hydrolysates can also be used. This adhesion promoter is preferably used in amounts of 1 to 20% by weight, preferably in amounts of 1 to 10% by weight, and particularly preferred in amounts of 2 to 8% by weight. The products according to the invention can contain aqueous emulsions of silicone resins (5) preferably of the general formula (R3SiO? Y2) a (RSi? 3/2) b. so-called MT resins and / or MQ resins of the general formula (R3SiO? / 2) a (Si? 4y2) b, in which R has the meaning mentioned above and is preferably a methyl, phenyl or vinyl radical, or hydrogen. The ratio of a to b is selected in such a way that the silicone resins are comprised in a viscosity range of preferably -300,000 mPa-s at 25 ° C. Preferably silicone resins are selected in the viscosity range of 50-30,000 mPa-s at 25 ° C, and particularly preferably in the viscosity range of 50 to 10,000 mPa-s at 25 ° C. The organosilicon compounds used according to the invention are commercial products or products that can be prepared according to conventional processes in the chemistry of silicones. As regards the organosilicon compounds used according to the invention, they can each be a single class of organic silicon compounds of this type or a mixture of different organic silicon compounds. For the preparation of the aqueous emulsions containing the constituents mentioned above, any emulsifiers (6) which are used in general for the preparation of organopolysiloxane emulsions can be used. Nonionic emulsifiers are preferred. Suitable emulsifiers are preferably ionic and nonionic emulsifiers. Examples thereof are sulfonic acid and its salts, which may act as emulsifiers, as well as alkylsulfonates, such as sodium lauryl sulphonate, benzene sulfonates substituted with aliphatic hydrocarbon radicals, such as sodium dodecylbenzenesulfonate, naphthalene sulfonates substituted with aliphatic hydrocarbon radicals, polyethylene glycol sulfonate and lauryl phosphate, poly (ethylene oxide), poly (propylene oxide), copolymers of ethylene oxide and propylene oxide, stearates and phosphates. These are used in amounts of 3% to 20%, based on the total content of Siiicone.

In the case of carbon black it is preferably gas black, furnace black or flame black. Additionally, preferably aqueous dispersions of carbon black can be used, which can be obtained commercially under the designations DERUSSOL, SCHWARZDISPERSION or RUßDISPERSION from Degussa. The carbon black dispersions may preferably have a solids content of 1 to 50% by weight. The primary particle size of the carbon blacks used may be between 10 and 100 nm. The dispersions can be anionic, nonionic or mixed anionic / nonionic stabilized. The carbon black content, based on the solids content of the silicone, is between 1 and 50% by weight, preferably between 3 and 40% by weight, and most preferably between 5 and 20% by weight . In addition to the constituents mentioned hitherto, the emulsions corresponding to the emulsion may preferably still contain other constituents, such as fillers, for example aluminum oxide, aluminum hydroxide, pigments and stabilizers. A further object of the invention is a process for the preparation of the aqueous emulsions corresponding to the invention, characterized in that the constituents (1) to (8) are emulsified. In the process according to the invention, the constituents are emulsified with one another: (1) organopolysiloxanes having vinyl groups attached to SiC in the terminal units, (2) organopolysiloxanes possessing at least 3 hydrogen atoms attached to Si, (3) catalyst that promotes the addition of hydrogen bound to Si to multiple aliphatic bonds, (4) organic silicon compounds suitable as adhesion promoters, (5) silicone resins, (6) emulsifier, (7) water, (8) black carbon, preferably at room temperature (25 ° C) and preferably at normal pressure. However, emulsions / dispersions prepared from the simple components can also be mixed. The process can also be carried out at reduced or elevated pressure and at a relatively high temperature to preferably 80 ° C or relatively low temperature to preferably 0 ° C, although room temperature is preferred for economic reasons. A further object of the invention is a process for coating textile substrates, characterized in that the aqueous emulsions corresponding to the invention are applied to a textile product and the emulsions are cured in a single step on the textile substrates and the textile is dried coated.

In the process according to the invention, the aqueous emulsions according to the invention can preferably be applied to wet textile products, which come directly from a washing or cleaning process. The vulcanization of the silicone coating and the drying and shrinking of the textile products can be carried out in a single operation. A further object of the invention is a vulcanized material that can be prepared using an aqueous emulsion corresponding to the invention, which is heated. In order to avoid premature crosslinking, the emulsions corresponding to the invention are stored in at least two different components. One component preferably contains the siloxanes with the unsaturated aliphatic groups, and another component preferably contains the siloxanes which possess Si-bonded hydrogen. The respective adjuvants and additives may be contained in one or both components. The application of the products corresponding to the invention can be carried out in a conventional manner. Examples are: immersion and calendering in fouling, painting, pouring, spraying, roller application, stamping, application with doctor blade, with a Meyer rod or with a paint gun or by padding in the case of application in the laminator, and serigraphy. The application of the coating material takes place during the washing process or immediately after the washing process.

The vulcanization is carried out in a single operation simultaneously with the drying and shrinking process. In the case of fabrics that have to be washed and dried, which is particularly applicable to fabrics of artificial fibers, the composition according to the invention can preferably be applied directly on the still wet fabric immediately after the washing operation. The vulcanization is carried out simultaneously with the drying operation. This is particularly desirable and especially advantageous in the case of fabrics that are used for the production of airbags. After application according to the aforementioned methods, the drying and vulcanization of the coated fabric is conventionally carried out in a heating channel, which can be heated by hot air, infrared light, gas burners, heat exchangers or other energy sources. In order to prevent the formation of blisters, a preliminary drying is carried out in a first zone preferably at temperatures of 60-150 ° C, more preferably 80-130 ° C, and especially preferably 90-120 ° C, and cross-linking it is carried out in a second zone, preferably at temperatures of up to 300 ° C. However, due to the limited thermal stability of most artificial fibers, a temperature range of preferably 120-190 ° C is preferred. The residence time required for vulcanization depends on the coating weight, the thermal conductivity of the fabric and the heat transfer to the coated textile material, and may be between 0.5 and 30 minutes. In addition to being able to be carried out in most conventional heating channels, drying and vulcanization can also be carried out in other industrial drying facilities, such as hot roll calenders, hot rolling presses, plate presses susceptible to heating or hot contact rollers, as well as by means of suspended dryers. Likewise, the coated textile materials according to the invention can be dried and vulcanized by microwaves. The products according to the invention can be used for coating or finishing textile materials of all kinds. Fabrics of all kinds of weaving, non-woven fabrics, knitwear, knits, knitwear, knitwear of all yarns and conventional fibers can be coated, natural fibers such as cotton, glass, wool, silk, artificial fibers, such as polyamides, polyester-viscose, polyethylene, polypropylene, polyurethane, silk, viscose, and cellulose. The fields of application of these textile materials thus finished are multiple. Examples of these are: sportswear, sports articles, such as candles, coatings for boats, or materials for backpacks and tents, as well as protective clothing. Technical applications, such as tarpaulins, conveyor belts, compensators, and collapsible containers. In a particularly advantageous manner, according to the process according to the invention, polyamide or polyester fabrics finished with the products according to the invention can be used for the preparation of automotive airbags.

Industrial fabrics have to be washed, dried and shrunk in most cases in order to meet the high demands. This is particularly applicable in the case of employment for the preparation of airbags. All the coating processes known up to now require a separate coating process after washing and drying. According to the process according to the invention, the coating material according to the invention can be applied immediately on or after the washing process, and vulcanized during the drying operation. An additional coating operation is no longer necessary. This means a significant saving of energy, time and costs. For the production of airbags, coated fabrics are often used. The coated fabrics according to the invention exhibit several technical advantages. The coating according to the invention offers protection against the hot gases of the fuel mixture, and the thread-to-wire friction, which leads to the reduction of the breaking strength and is caused by vibrations, can be prevented by a corresponding elastomer coating to the invention. The coating according to the invention gives the fabric improved aging resistance and flame resistance. An advantage of the coating process according to the invention is that the costs of an additional coating step are eliminated. According to the invention, an aqueous silicone system is provided which is applied immediately after the washing operation to the still wet fabric, and can be vulcanized during the drying operation.

This coating system according to the invention is an aqueous silicone coating system, which, after vulcanization, exhibits exactly the properties profile suitable for an airbag.

EXAMPLES EXAMPLE 1 4. 000 g of an aqueous emulsion, containing 800 g of a dimethyl polysiloxane having vinyl dimethylsiloxy units as terminal units, having a viscosity of 1,000 mPa-s, 800 g of a dimethyl polysiloxane having vinyl dimethylsiloxy units as terminal units with a viscosity of 20,000 mPa s, 20 g of a platinum-divinite tetramethyldisiloxane complex containing 1% by weight of platinum, 10 g of ethynylcyclohexanol, 90 g of a diorganopolysiloxane blocked at the ends by trimethylsiloxy groups with 50% by mole of methylhydrogensiloxane units and 50% by weight. moles of dimethylsiloxane units and a viscosity of 120 mPa-s as well as and 1080 g of an aqueous dispersion of a flame black with a primary particle size of 15 nm and a solids content of 21% by weight, and 300 g of an aqueous emulsion of a silicone resin of the formula With a viscosity of 2,000 mPa-s, they are mixed with stirring at the temperature environment and normal pressure. This mixture is preloaded at room temperature (25 ° C) and at normal pressure in an immersion tank. This emulsion is applied with an impregnation roller on a 235 dtex wet polyamide fabric. The coated fabric passes through a heating channel, which in the first zone reaches an air temperature of 100 ° C and in a second zone an air temperature of 180 ° C. The residence time in this heating channel is 3 minutes. A fabric with a silicone coating of 34 g / m2 is obtained. The tissue has the following properties: Air permeability according to DIN 53530: 1, 16 l / dm2 / min Adhesive coating according to DIN 53530: 80 N / 5 cm Scrub Test according to ISO 5981: minimum 600 Burning speed according to FMVSS 302: 45 mm / min The combustion rate according to FMVSS 302 is determined in the horizontal combustion test.

The combustion rate according to FMVSS 302 is determined in the horizontal combustion test.

COMPARATIVE EXAMPLE 2 The procedure described in Example 1 is repeated, with the difference that no type of carbon black is used. A fabric with the following properties is obtained: Coating weight: 18 g /? T Air permeability according to DIN 53887: 1, 16 l / dm2 / min Adhesion of the cladding according to DIN 53530: 80 N / 5 cm Scrub Test according to ISO 5981: 600 Combustion speed according to FMVSS 302: 70 mm / min The combustion rate according to FMVSS 302 is determined in the horizontal combustion test.

EXAMPLE 3 The procedure described in example 1 is repeated, with the difference that the formulation described in example 1 contains, instead of flame black, 200 g of an aqueous black oven dispersion with a solids content of 48. % by weight and a primary particle size of 27 nm. A 110 dtex fabric was coated. A fabric with the following properties is obtained: Coating weight: 17 g / m2 Air permeability according to DIN 53887: 1, 24 l / dm2 / min Coating adhesion according to DIN 53530: 110 N / 5 cm Scrub Test according to ISO 5981: 800 Burning speed according to FMVSS 302: self-extinguishing The combustion rate according to FMVSS 302 is determined in the horizontal combustion test.

EXAMPLE 4 The procedure described in Example 3 was repeated, with the difference that no carbon black dispersion was added. A fabric with the following properties is obtained: Coating weight: 16 g / rt? Air permeability according to DIN 53887: 1, 22 l / dm2 / min Adhesion of the cladding according to DIN 53530: 100 N / 5 cm Scrub Test according to ISO 5981: 800 Combustion speed according to FMVSS 302: 115 mm / min The combustion rate according to FMVSS 302 is determined in the horizontal combustion test.

Claims (9)

NOVELTY OF THE INVENTION CLAIMS

1. - Aqueous emulsions, characterized in that they contain (1) organopolysiloxanes which have in the terminal units groups linked to SiC with multiple aliphatic bonds, (2) organopolysiloxanes possessing at least 3 hydrogen atoms attached to Si, (3) catalyst promoting the addition of hydrogen bound to Si to the multiple aliphatic bonds, (4) organic silicon compounds suitable as adhesion promoters, (5) silicone resins, (6) emulsifier, (7) water and (8) carbon black. 2. Aqueous emulsion according to claim 1, characterized in that in the case of the organopolysiloxanes (1) having vinyl groups attached to SiC in the terminal units, they are compounds of this type of the general formula

(CH2 = CH) xSiR3-x-O (S¡R2?) NS¡R3.x (CH = CH2) x wherein R means the same or different hydrocarbon radicals which may be substituted and X is 1, 2 or 3 and n is an integer with a value such that the diorganopolysiloxanes (1) preferably have an average viscosity of 100-500,000 mPa-s at 25 ° C.

3. - Aqueous emulsion according to claim 1 or 2, characterized in that in the case of the organopolysiloxanes (2) having at least 3 hydrogen atoms bonded to Si are compounds of this type of the general formula

(CH3) 3S¡O- (SiHRO) or- (S¡R2?) P-S¡ (CH3) 3, in which R has the meanings indicated above and o / p is comprised in the ratio of 1: 0 to 1: 20. 4. Aqueous emulsion according to one or more of claims 1 to 3, characterized in that in the case of the silicone resins (5) these are silicone resins of the general formula (R3SiO? / 2) to (RSi? 3/2) b, called MT resins and / or MQ resins of the general formula (R3SiO? / 2) to (S¡? 4/2) b, in which R has the meaning indicated above and the ratio of aab is selected in such a way that the silicone resins are in a range of viscosity of 30-300,000 mPa-s at 25 ° C.

5. Process for the preparation of aqueous emulsions according to one or more of claims 1 to 4, characterized in that constituents 1-7 are emulsified.

6. Vulcanized, which can be prepared by using an aqueous emulsion according to one or more of claims 1 to 4 or that can be prepared according to claim 5, in which the emulsion is heated.

7. - Process for the coating of textile substrates, characterized in that aqueous emulsions according to one or more of claims 1 to 4 or that can be prepared according to the process according to claim 5 are applied on a textile material and the emulsions are vulcanized in a single step on the textile substrates and the coated textile material is dried.

8. Textile coated substrates, characterized in that the textile substrates are coated with emulsions according to one or more of claims 1 to 4 or that can be prepared according to claim 5. 9.- Coated textile substrate, characterized in that the substrate Textile is an airbag material.