DE10046892A1 - Coating of textile articles where high tear strength and low weight are required, comprises addition-crosslinkable silicone composition comprising two diorganopolysiloxanes, crosslinking agent and hydrosilylation catalyst - Google Patents

Abstract

Coating of textile articles comprises applying an addition-crosslinkable silicone composition, comprises a diorganopolysiloxane with two terminal alkenyl groups, a diorganopolysiloxane with one terminal alkenyl group, a crosslinking agent having at least two Si-H atoms, and a hydrosilylation catalyst. Coating of textile articles comprises applying an addition-crosslinkable silicone composition comprises: (A) a diorganopolysiloxane having a viscosity of 50 - 100,000 mPas at 25 deg C and comprises two units of formula (I), units of formula (II) and 0 - 0.3 wt.% of units of formula (III). R = optionally halo- or cyano-substituted 1-18C hydrocarbyl groups free of aliphatic carbon-carbon multiple bonds; R<1> = optionally halo- or cyano-substituted 1-10C alkenyl groups optionally bonded to Si through a divalent organic group. (B) is a diorganopolysiloxane having a viscosity of 10 - 100,000 mPas at 25 deg C and comprises one unit of formula (I), units of formula (II) and one unit of formula (IV). (C) is a crosslinking agent that contains at least two silicon-bonded hydrogen atoms and has empirical formula (V). R<2> = a group as defined for R; a, b = non-negative integers such that a+b is 0.5 - 3, a is 0 - 2. (D) a hydrosilylation catalyst.

Description

The invention relates to a method for coating textile fabric with addition-crosslinkable silicone material, the curing of the silicone mass and the coated textile Fabrics.

In Bärbel Böddeker, "Silicone and airbags - two worlds merge? ", Article on the occasion of the 4th International Akzo Nobel symposium for vehicle occupant restraint systems from 24. until April 26, 1996 in the Maritim Hotel Bonn, it is described that the tear resistance of polyamide 6.6 fabrics Coating with liquid silicone rubber depending on the coating weight can be increased up to 60%.

The task was to ensure the tear resistance of silicon coated textile fabric to increase further.

The invention relates to a method for coating textile fabrics, in which addition-crosslinkable silicone material

• A) diorganopolysiloxane with a viscosity of 50 mPa.s to 100,000 mPa.s determined at 25 ° C., built up from 2 units of the general formula (1)
  [R ₂ R ¹ SiO _1/2 ] (1)
  Units of the general formula (2)
  [R ² SiO _2/2 ] (2),
  and
  0 to 0.3% by weight of units of the general formula (3)
  [RR ¹ SiO _2/2 ] (3)
  where in the general formulas (1) to (3)
  R are identical or different monovalent, optionally halogen or cyano-substituted, via SiC-bonded C ₁ -C ₁₈ hydrocarbon radicals which are free from aliphatic carbon-carbon multiple bonds and
  R ^{1 is the} same or different monovalent, optionally halogen or cyano-substituted, optionally bonded to silicon via an organic divalent group C ₁ - C ₁₀ alkenyl groups,
• B) diorganopolysiloxane with a viscosity of 10 mPa.s to 10,000 mPa.s determined at 25 ° C., composed of 1 unit of the general formula (1), units of the general formula (2) and 1 unit of the general formula (4) ,
  [R ₃ SiO _1/2 ] (4)
• C) SiH-functional crosslinking agent, the composition of which corresponds to the average general formula (5)
  H _a R ² _b SiO _{(4-ab) / 2} (5),
  corresponds in which
  R ^{2 has} the meanings of R and
  a and b are non-negative integers, with the proviso that 0.5 <(a + b) <3.0 and 0 <a <2 and that there are at least two silicon-bonded hydrogen atoms per molecule and,
• D) contain hydrosilylation catalyst, is applied to the textile fabric.

By adding monofunctional diorganopolysiloxane (B) to the silicone rubber composition can drastically improve the Tear resistance of the silicone-coated textiles Fabric can be achieved.

Examples of unsubstituted hydrocarbon radicals R are Alkyl radicals, such as the methyl, ethyl, n-propyl, iso-propyl, n-  Butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, neo- Pentyl, tert-pentyl, hexyl, such as the n-hexyl, Heptyl residues, such as the n-heptyl residue, octyl residues, such as the n- Octyl radical and iso-octyl radicals, such as the 2,2,4- Trimethylpentyl radical, nonyl radicals, such as the n-nonyl radical, Decyl radicals, such as the n-decyl radical, dodecyl radicals, such as the n- Dodecyl radical, octadecyl radicals, such as the n-octadecyl radical; Cycloalkyl radicals, such as cyclopentyl, cyclohexyl, 4- Ethylcyclohexyl, cycloheptyl, norbornyl and Methylcyclohexyl residues; Aryl radicals, such as the phenyl, biphenylyl, Naphthyl, anthryl and phenanthryl; Alkaryl residues, such as o-, m, p-tolyl, xylyl and ethylphenyl; Aralkyl radicals, such as the benzyl radical, the alpha- and the β- Phenylethyl radical, as well as the fluorenyl radical.

Examples of substituted hydrocarbon radicals as radicals R are halogenated hydrocarbons, such as chloromethyl, 3- Chloropropyl, 3-bromopropyl, 3,3,3-trifluoropropyl and 5,5,5,4,4,3,3-hexafluoropentyl radical and the chlorophenyl, Dichlorophenyl and trifluorotolyl.

The hydrocarbon radical R is preferably unsubstituted and substituted C ₁ -C ₆ -alkyl radicals and the phenyl radical, in particular the methyl radical.

The alkenyl groups R ¹ are amenable to an addition reaction with the SiH-functional crosslinking agent (B).

Alkenyl groups with 2 to 6 Carbon atoms, such as vinyl, allyl, methallyl, 1-propenyl, 5-hexenyl, ethynyl, butadienyl, hexadienyl, cyclopentenyl, Cyclopentadienyl, cyclohexenyl, preferably vinyl and allyl, used.

Organic divalent groups via which the alkenyl groups R ¹ can be bonded to silicon in the polymer chain consist, for example, of oxyalkylene units, such as those of the general formula (6)

- (O) _m [(CH ₂ ) _n O] _o - (6),

in the
m the values 0 or 1, in particular 0,
n values from 1 to 4, in particular 1 or 2 and
o Values from 1 to 20, in particular from 1 to 5. In this formula, the oxyalkylene units of the general formula (6) are bonded on the left to a silicon atom.

The diorganopolysiloxane (A) preferably has one at 25 ° C. certain viscosity of at least 1000 mPa.s, in particular at least 2000 mPa.s and at most 50 000 mPa.s, in particular at most 30,000 mPa.s.

The diorganopolysiloxane (A) preferably has 0 to 0.1% by weight, in particular no units of the general formula (3).

Preferably diorganopolysiloxane (A) is in an amount of at least 20% by weight, particularly preferably at least 30% by weight, in particular at least 40% by weight and at most 95% by weight, particularly preferably at most 90% by weight, in particular at most 85 wt .-%, each based on the total silicone mass available.

The diorganopolysiloxane (B) preferably has one at 25 ° C. certain viscosity of at least 30 mPa.s, in particular at least 100 mPa.s and at most 5000 mPa.s, in particular at most 3000 mPa.s.

Preferably diorganopolysiloxane (B) is in an amount of at least 1% by weight, particularly preferably at least 4% by weight, in particular at least 7% by weight and at most 50% by weight, particularly preferably at most 40% by weight, in particular at most 30% by weight, based on the total silicone mass available.  

The use of one or more SiH bonds is preferred per molecule containing crosslinking agent (C). Using one with only two SiH bonds per molecule The use of a crosslinking agent is recommended Diorganopolysiloxane (A) that has at least three Alkenyl groups per molecule.

The hydrogen content of the crosslinking agent (C), which is exclusively on those directly bound to silicon atoms Related hydrogen atoms is preferably in the range of 0.002 to 1.7% by weight of hydrogen, preferably from 0.1 to 1.7 % By weight of hydrogen.

The crosslinking agent (C) preferably contains at least three and at most 600 silicon atoms per molecule. The is preferred Use of crosslinking agent (C), the 4 to 200 Contains silicon atoms per molecule.

The crosslinking agent (C) preferably has one at 25 ° C. certain viscosity of at least 10 mPa.s, especially preferably at least 20 mPa.s, in particular at least 30 mPa.s and at most 5000 mPa.s, particularly preferably at most 3000 mPa.s, in particular at most 1000 mPa.s.

The structure of the crosslinking agent (C) can be linear, branched, be cyclic or network-like.

Particularly preferred crosslinking agents (C) are linear polyorganosiloxanes of the general formula (7)

(HR ³ ₂ SiO _1/2 ) _c (R ³ ₃ SiO _1/2 ) _d (HR ³ SiO _2/2 ) _e (R ³ ₂ SiO _2/2 ) _f (7),

in which
R ^{3 have} the meanings of R and the non-negative integers c, d, e and f have the following relations: (c + d) = 2; (c + e) <2, 5 <(e + f) <200 and f: e is in the range 0: 1 to 20: 1, preferably 0: 1 to 15: 1, in particular 0: 1 to 10: 1.

Preferably, in the general formula (7), c = 0.

The SiH functional crosslinking agent (C) is preferably in such an amount in the crosslinkable silicone rubber composition contain that the molar ratio of SiH groups to Alkenyl groups at 0.5 to 5, especially at 1.0 to 3.0 lies.

Crosslinking agent (C) is preferably present in an amount of at least 0.3% by weight, particularly preferably at least 0.5% by weight, in particular at least 0.8% by weight and at most 30% by weight, particularly preferably at most 20% by weight, in particular at most 10% by weight, based on the total silicone mass available.

All known catalysts can be used as the hydrosilylation catalyst (D) which catalyze the hydrosilylation reactions which occur in the crosslinking of addition-crosslinking silicone compositions. As hydrosilylation catalysts (D), in particular metals and their compounds, such as platinum, rhodium, palladium, ruthenium and iridium, preferably platinum, can be used. Platinum and platinum compounds are preferably used. Platinum compounds which are soluble in polyorganosiloxanes are particularly preferred. Soluble platinum compounds which can be used are, for example, the platinum-olefin complexes of the formulas (PtCl ₂ .olefin) ₂ and H (PtCl ₃ .olefin), preference being given to alkenes having 2 to 8 carbon atoms, such as ethylene, propylene, isomers of butene and octene , or cycloalkenes having 5 to 7 carbon atoms, such as cyclopentene, cyclohexene and cyclo heptene, can be used. Other soluble platinum catalysts are the platinum-cyclopropane complex of the formula (PtCl ₂ C ₃ H ₆ ) ₂ , the reaction products of hexachloroplatinic acid with alcohols, ethers and aldehydes or mixtures thereof, or the reaction product of hexachloroplatinic acid with methylvinylcyclotetrasiloxane in the presence of sodium bicarbonate in ethanolic solution. Complexes of platinum with vinylsiloxanes, such as sym-divinyltetramethyl disiloxane, are particularly preferred.

Hydrosilylation catalyst (D) can be in any form are used, for example in the form of Hydrosilylation catalyst containing microcapsules or Organopolysiloxane particles.

The hydrosilylation catalyst (D) content is preferred chosen so that the addition-crosslinkable silicone composition has a Pt Content of at least 0.1 ppm, preferably at least 2 ppm, in particular at least 5 ppm and at most 200 ppm, preferred has at most 80 ppm, in particular at most 40 ppm.

The mechanical strength of the vulcanized silicone rubber is increased if the addition-crosslinkable silicone compositions contain actively reinforcing fillers as component (E). The active reinforcing fillers (E) used are, in particular, highly disperse precipitated and pyrogenic silicas, and mixtures thereof. The preferred specific surface area of the fillers (E) is at least 10 m ² / g, preferably at least 30 m ² / g, in particular at least 50 m ² / g and at most 400 m ² / g, preferably at most 300 m ² / g, in particular at most 200 m ² / g as determined by the BET method. Hydrophobized fillers are preferably used as component (E). Such active reinforcing fillers are very well known materials in the field of silicone rubbers.

The content of the addition-crosslinkable silicone compositions is active reinforcing filler (E) is preferably at least 1 % By weight, particularly preferably at least 5% by weight, in particular at least 7% by weight, and at most 50% by weight, especially preferably at most 40% by weight, in particular at most 35% by weight, each based on the total silicone mass.  

The addition-crosslinkable silicone mass can heat stabilizer (F) included. Are suitable as heat stabilizers (F) for example metal compounds such as iron salts, cerium salts of Carboxylic acids, especially ceroctoate, reaction products of Platinum vinyl siloxane complexes with aminoalkoxysilanes, such as described in US-A-5,008,317, to which express reference is taken (is incorporated by reference), metal oxides, such as Titanium dioxide, manganese dioxide, zirconium dioxide, zinc oxide, Cerium (III) oxide, cerium (IV) oxide and iron oxides.

Preferably, heat stabilizer (F) is in an amount of at most 3% by weight, particularly preferably at most 2% by weight, in particular at most 1% by weight, based in each case on the entire silicone mass available.

The addition-crosslinkable silicone material can inhibitor (G) included, which extends the pot life. Preferred as an inhibitor (G) is ethynylcyclohexanol.

The content of the addition-crosslinkable silicone mass inhibitor (G) is preferably at least 0.01% by weight, particularly preferably at least 0.02% by weight, in particular at least 0.03 % By weight, and at most 2% by weight, particularly preferably at most 1 % By weight, in particular at most 0.5% by weight, in each case based on the entire silicone mass.

The addition-crosslinkable silicone composition may further contain silicone (H) which has neither alkenyl groups nor Si-H groups. (H) is preferably composed of units of the general formula (2) and 2 units of the general formula (7)

[R ² R ³ SiO _1/2 ] (7)

in which R has the above meanings and R ^{3 has} the meaning HO or R. Silicon (H) can influence the mechanical properties and serves in particular as a plasticizer.

The silicone (H) preferably has one determined at 25 ° C. Viscosity of at least 30 mPa.s, in particular at least 100 mPa.s and at most 5,000 mPa.s, in particular at most 3000 mPa.s.

Silicon (H) is preferably present in an amount of at most 10 % By weight, particularly preferably at most 5% by weight, in particular at most 1% by weight, based on the total Silicone compound available.

The addition-crosslinkable silicone compositions can optionally be used as Components (I) further additives in a proportion of up to 70 % By weight, preferably from 0.01 to 40% by weight. This Additives can e.g. B. non-reinforcing fillers, Flame retardants, dispersing aids, adhesion promoters, Pigments, dyes and catalysts.

The compounding of the addition-crosslinkable silicone materials is done by mixing the above components in in any order. Preferably the last component the SiH-functional crosslinking agent (C) is mixed in.

The pot lives are preferably from 0.5 hours to 20 Hours set. Residence times of are particularly preferred 0.5 hours to 15 hours, in particular from 1 hour to 10 Hours.

Small quantities can be mixed with a spatula happen. For larger quantities, mixing devices such as stirrers, Dissolvers, kneaders and the like preferable.

The coating material thus produced is preferably used a squeegee on the textile fabric to be coated upset. All types of knife coating can be used Come into play. Examples are: air knife, roller knife,  Table squeegee or squeegee over blanket. As an alternative to Doctor blade technology can also the silicone mass by spraying, Spraying, extrusion, dipping and stripping or dipping and Padding can be applied. All kinds of Roll coatings, such as engraving rollers, splashing or application Multi-roller systems and screen printing are possible. For this If necessary, the silicone mass can be mixed with organic solvents be diluted.

The addition-crosslinkable silicone compositions are crosslinked preferably by heating, preferably in a heating oven, preferably at 30 to 250 ° C, preferably at least 50 ° C, especially at at least 100 ° C, preferably at most 200 ° C, especially at a maximum of 180 ° C. The networked Silicone rubber layer to an elastomer layer. The Crosslinking time essentially depends on the temperature can in particular take 20 seconds to 5 minutes.

The addition-crosslinkable silicone materials can be used for coating of textile fabrics such as woven fabrics, knitted fabrics, scrims, Knitted fabrics, fleeces and felts can be used.

The invention also relates to the coated textiles Flat structures made by networking the addition-crosslinkable Silicone compounds are available.

The coated textile fabrics can be everywhere be used where high weight is as low as possible Tear resistance is advantageous. examples are Paragliders, parachutes, hot air balloons, casual wear, Leisure items such as tents or backpacks, sails or airbags. In the technical area, the coated textiles Flat structures advantageous for example for conveyor belts, Compensators, awnings, or used in the insulation area.  

In the following examples, unless otherwise stated,

• a) all pressures 0.10 MPa (abs.);
• b) all temperatures 20 ° C.

Examples

General description of silicone rubber production:
The diorganopolysiloxane (A) is placed in a Z kneader and incorporated while kneading the filler (E). When all the filler has been added, kneading is continued for 2 hours. The substrate heats up to approx. 80 ° C due to the friction. The mass is cooled to about 40 ° C and then incorporated with kneading heat stabilizer (F), hydrosilylation catalyst (E), inhibitor (G) and optionally diorganopolysiloxane (B) and (H). After a further hour of kneading, the homogeneous mass is filled with 50 µ on a strainer sieve.

Example 1 (comparative example)

942.4 g of a vinyl-terminated dimethylpolysiloxane (A) with a viscosity of 7000 mPa.s are introduced and 230.4 g of highly disperse silica (E) with a BET surface area of 130 g / m ^{2 are} kneaded. With further kneading, the following are added:
0.5 g 12% Ceroctoate (F) in iso-octane,
2 g of a Pt complex in tetramethyldivinyldisiloxane with a Pt content of 1% by weight (D),
1.1 g ethynylcyclohexanol (G),
253 g of a vinyl-terminated dimethylpolysiloxane with a viscosity of 500 mPa.s (A).
After 4 hours of kneading, the 80 ° C silicone mass is filled.
After cooling, a transparent mass with a viscosity of 80,000 mPa.s is obtained.

Example 2 (comparative example)

942.4 g of a vinyl-terminated dimethylpolysiloxane (A) with a viscosity of 7000 mpas are introduced and 230.4 g of highly disperse silica (E) with a BET surface area of 130 g / m ^{2 are} kneaded in. With further kneading, the following are added:
0.5 g 12% Ceroctoate (F) in iso-octane.
2 g of a Pt complex in tetramethyldivinyldisiloxane with a Pt content of 1% by weight (D),
1.1 g ethynylcyclohexane oil (G),
196 g of a vinyl-terminated dimethylpolysiloxane with a viscosity of 500 mpas (A),
57 g of a dimethylpolysiloxane of the formula

(CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] ₁₀₀ Si (CH ₃ ) ₃ (H).

After 4 hours of kneading, the 80 ° C silicone mass is filled.
After cooling, a transparent mass with a viscosity of 80,000 mPa.s is obtained.

Example 3

942.4 g of a vinyl-terminated dimethylpolysiloxane (A) with a viscosity of 7000 mPa.s are introduced and 230.4 g of highly disperse silica with a BET surface area of 130 g / m ^{2 are} kneaded in.
With further kneading, the following are added:
0.5 g Ceroctoat (F) 12% in iso-octane,
2 g of a Pt complex in tetramethyldivinyldisiloxane with a Pt content of 1% by weight (D),
1.1 g ethynylcyclohexanol (G),
253 g of a mixture of 40 mol% vinyl-terminated dimethylpolysiloxane (A), 50 mol% one-sided vinyl-terminated dimethylpolysiloxane (B) and 10 mol% methyl-terminated dimethylpolysiloxane (H), each of which has a viscosity of 500 mPa.s.
After 4 hours of kneading, the 80 ° C silicone mass is filled. After cooling, a transparent mass with a viscosity of 80,000 mPa.s is obtained.

Fabric coating

To produce a functional coating composition, 100 g each of the silicone rubber from Examples 1 to 3 are mixed with 3 g of a crosslinking agent (C) of the formula

(CH ₃ ) ₃ SiO [Si (CH ₃ ) ₂ O] ₆₀ [SiO (CH ₃ ) H] ₂₀ Si (CH ₃ ) ₃

mixed.

Various fabrics are coated with the coating compositions described using a doctor blade and vulcanized at 170 ° C. for 3 minutes.
Coating weight: 30 g / m ²

The tear strength (WRF) of the coated fabrics is then measured.

Claims (7)

1. Process for coating textile fabrics, in which addition-crosslinkable silicone materials, the

• A) diorganopolysiloxane with a viscosity of 50 mPa.s to 100,000 mPa.s determined at 25 ° C., built up from 2 units of the general formula (1)
  [R ² R ¹ SiO _1/2 ] (1),
  Units of the general formula (2)
  [R ² SiO _2/2 ] (2), and
  0 to 0.3% by weight of units of the general formula (3)
  [RR ¹ SiO _2/2 ] (3)
  where in the general formulas (1) to (3)
  R are identical or different monovalent, optionally halogen or cyano-substituted, via SiC-bonded C ₁ -C ₁₈ hydrocarbon radicals which are free from aliphatic carbon-carbon multiple bonds and
  R ^{1 is the} same or different monovalent, optionally halogen or cyano-substituted, optionally bonded to silicon via an organic divalent group C ₁ - C ₁₀ alkenyl groups,
• B) diorganopolysiloxane with a viscosity of 10 mPa.s to 10,000 mPa.s determined at 25 ° C., composed of 1 unit of the general formula (1), units of the general formula (2) and 1 unit of the general formula (4) ,
  [R ³ SiO _1/2 ] (4)
• C) SiH-functional crosslinking agent, the composition of which corresponds to the average general formula (5)
  H _a R ² _b SiO _{(4-ab) / 2} (5),
  corresponds in which
  R ^{2 has} the meanings of R and
  a and b are non-negative integers, with the proviso that 0.5 <(a + b) <3.0 and 0 <a <2 and that there are at least two silicon-bonded hydrogen atoms per molecule and,
• D) contain hydrosilylation catalyst to which textile fabrics are applied.

2. The method according to claim 1, wherein the RC ₁ - to C ₆ -alkyl radicals or phenyl radical. 3. The method according to claim 1 or 2, wherein the diorganopoly siloxane (A) in an amount of 20 to 95 wt .-%, each based on the total silicone mass is present. 4. The method according to claim 1 to 3, wherein the diorganopoly siloxane (B) in an amount of 1 to 50 wt .-%, each based on the total silicone mass is present. 5. The method according to claim 1 to 4, in which as active reinforcing filler (E) highly disperse silica in the silicone mass is present. 6. The method according to claim 1 to 5, wherein the coated Textile fabrics for networking the addition-crosslinkable silicone materials is heated. 7. Coated textile fabric, available after A method according to claims 1 to 6.