DE19756906A1 - Composition containing film forming alkoxysilane sol, aluminum or zirconium halide and a crosslinkable compound - Google Patents

Abstract

A coating agent for textile or polymeric materials comprises a film forming alkoxysilane based sol, aluminum or zirconium halide and a crosslinkable compound. A coating agent (I) for textile or polymeric materials comprises: (A) a film forming organosol, formed by cohydrolysis of (A1) a tetraalkoxysilane of formula Si(OR<1>)4 (1), (A2) a trialkoxy silane of formula R<2>Si(OR<1>)3 (2) and/or (A3) a dialkoxysilane of formula R<3>2Si(OR<1>)2 (3) in an organic solvent; (B) an aluminum or zirconium halide in an aqueous organic solvent and (C) a crosslinkable compound with at least 2 hydroxy groups. R<1> and R<3> = 1-4C alkyl; R<2> = 1-18C alkyl or fluoroalkyl or an epoxy functionalized alkyl or cycloalkyl. An Independent claim is included for a coating process using (I) by production of (A) by cohydrolysis in an organic solvent, addition of (B) and (C) dissolved in aqueous alcohol, coating a material, drying and hardening of the layer.

Description

The invention relates to a coating composition, in particular for textile or polymeric materials used to modify the Absorption and reflection behavior as well as for improvement the physical-mechanical properties of the coated or impregnated materials can be used.

It is generally known that numerous molded parts and Articles of daily use made of polymeric plastics with coatings be equipped to protect them from mechanical or chemical Protect damage. It is an important requirement that the Coatings should be hard, abrasion-resistant and ecologically harmless len. This requirement is from the commercially available organic Paint coatings insufficiently met. A coating with So far, inorganic coatings have required a complex Va vacuum technology. The temperatures in such processes are very high high, so that an application for organic substrates is limited is possible. In addition, this technology is device and energy consuming agile, discontinuous and unsuitable for complicated geo metric bodies. Therefore, there is a need for improvement processes for surface modification of polymers Products.

In a similar way, one strives in textile technology that to improve the physical-mechanical properties of the fabric and more beneficial properties of the tissues through post-treatments to lend ("textile finishing"). To be mentioned here for example, the improvement of wrinkle resistance, ore a certain hydrophobicity of the tissue or the errei flameproof equipment etc. This requires the substrate either by a chemical reaction and / or by adsorption  be modified on the substrate. These procedures are common technically very complex, ecologically not harmless or very expensive. Another problem is more adsorptive Procedure an insufficient permanent anchorage on the Fiber materials, so that the functional properties Reduce use.

Because of the shortcomings mentioned, efforts are being made to create new, cost-effective ones Permanent, low-energy, ecologically advantageous processes for the upper to develop surface modification of fabrics and plastics, to increase the utility value properties. As a new procedure for the production of thin metal oxide coatings on vacuum-free The sol-gel technique is an option.

To do this, stable metal oxide brines are produced by hydrolysis of metal alkoxides (1), which form thin metal oxide gel films on any supports by concentration during drying (2), e.g. B.

Me (OR) _n + n / 2 H ₂ O → (MeO _m ) _sol + n ROH (1)
(MeO _m ) _sol → (MeO _m ) _sol (2)

(Me = metal e.g. Si, Ti, Zr, Sn, Al, R = organic residue, e.g. B. alkyl, acyl).

The pure metal oxide coatings obtained in this way are not very stable mechanically, since a strong shrinking process takes place during the film formation process and the degree of crosslinking is low. For this reason z. B. impregnation of textile fibers with Al ₂ O ₃ sols (JP 69017595 and JP 02196884) or dispersions (US 86-824187) or SiO ₂ aquasoles (EP 0095922) too little abrasion-resistant coatings.

That is why one is currently trying to modify the Metal oxide sol structure the mechanical stability and ver wear resistance of the metal oxide gel films formed improve.  

One way is to use mixtures of different metal alkoxides to generate cross-linked metal oxide gels, e.g. B. SiO ₂ with Al ₂ O ₃ (US 5336560 A, US 5324 544 A), with TiO ₂ or ZrO ₂ (DE 42 17 432 A1) or a combination thereof (US 5262 362 A). In a similar way, attempts are made to improve the abrasion resistance by adding Al ₂ O ₃ (US 796 974 A0) or other ceramic powders (DE 43 07 665 A1).

Another way tries the organic modification of the Metal oxide brine z. B. by direct chemical bonding of alk oxysilane groups with vinyl polymers (EP 0065388) or composite formation with different polymers (WO 9301 226, EP 0047160) or resins (EP 497560 A2). The mechanical property can be improved significantly if you use organofunk tionalized alkoxysilanes (e.g. with acrylate groups or epo xidgruppen) co-condensed and thermally ver after gel formation nets. For this purpose, z. B. Systems of epoxysilanes with bispheno len (DE 35 20 749 A1) or polycarboxylic acids (EP 0407174 B1) as Crosslinker suggested. The overlays obtained in both ways ge do not meet the requirements in all cases Lich adhesion, abrasion resistance to mechanically stressed Commodities as well as the storage stability of the use ten brine.

The practical problem is that highly cross-linking Sy systems usually have a short service life, because after the Preparation of the coating solutions slow crosslinking uses that to an increasing solidification before loading layering process leads. On the other hand, they provide stable service life Coating solutions often unsatisfactory mechanical values, because the degree of crosslinking of the layer is insufficient. This pro blem was recently solved (DE 196 20 668 C1) that two modified metal oxide sols were combined that only at Heating can be effectively networked. This thermally curable Multi-component paints are used for the coating of textile or  polymeric materials due to their low thermal stability only suitable to a limited extent.

The object of the invention is to develop new possibilities Manufacture of coating materials, especially for textiles and polymeric sol-gel based materials that find a Ensuring long-term stability and still effective Crosslinking during layer formation at room temperature enable.

This task is accomplished by a coating agent and a process ren with the features according to claims 1 and 11 ge solves. Advantageous embodiments of the invention result from the dependent claims. Surprisingly, this could Task solved with simple means especially by who that a coating agent is used, which consists of 3 long-stable components (hereinafter as component A, B and C) immediately before coating be mixed, and after coating by a star ke adsorptive interaction with the substrate during the dry phase of excellent liability and good lead physical-mechanical properties. The invention is not limited to textile or polymeric materials, son applicable to all coatable materials.

According to the invention, component A consists of a solution which is mixed by acidic or alkaline-catalyzed hydrolysis of a mixture of a tetraalkoxysilane Si (OR ¹ ) ₄ (I), one or more trialkoxysilanes R ² Si (OR ¹ ) ₃ (II) and / or of a dialkoxysilane R ³ Si (OR ¹ ) ₂ (III) is formed in an organic solvent. The 3 components have the following functions:

• the tetraalkoxysilane (I, R ¹ = alkyl radicals with 1-4 C atoms) increases the stability and the service life of component A by co-condensation with (II) and (III) and improves the layer quality,
• - The trialkoxysilane R ² Si (OR ¹ ) ₃ functionalized by the choice of the radical R ^2, the coating agent, for. B. R ² = alkyl radical with 1-18 C atoms increases the hydrophobicity of the layer, R ² = fluoro alkyl radical with 1-18 C atoms increases the dirt and water repellent effect of the coating, R ² = epoxy-functionalized alkyl or cycloalkyl radical enables additional thermal post-curing by crosslinking with component 3,
• - The dialkoxysilane R ³ Si (OR ¹ ) ₂ (III, R ³ = alkyl radical with 1-4 C atoms) increases the flexibility and elasticity of the coating.

For the production of component A, cohydrolysis is advantageous mixtures of 10 parts by weight of a tetraalkoxysilane (I), 0.1 to 10 parts by weight of one or more trialkoxysilanes (II) and / or 0.1 to 5 parts by weight of a dialkoxysilane (III) used. The hydrolysis can be carried out by dilute acids, e.g. B. dilute hydrochloric acid, or dilute alkalis, such as aqueous Ammonia or caustic soda can be catalyzed. As a solution ver water-miscible solvents such as low molecular weight can re alcohols and ketones, cyclic ethers, alkyl glycols or ace tonitrile can be used.

Component B according to the invention consists of an aluminum or zirconium halide, preferably aluminum hydroxide chloride or zirconium oxide chloride, in an aqueous-organic solvent. For example, a 10% solution in 80% ethanol can be prepared with aluminum hydroxide chloride (commercially available e.g. as Locron S / Clariant). Component B has 3 important functions:

• - Crosslink or co-condense the metal salts with the compo nente A and thereby lead to an effective consolidation of the Coatings during the drying process Room temperature,
• - The basic metal salts are known to act as stains (especially for textile surfaces) and improve the adhesive dough properties of the coating, and possibly the dyeability,
• - The combination of components A and B provides one additional tempering as a result of formation of aluminosilicate  further improvement of the physical-mechanical properties ten (hardness, abrasion).

According to the invention, component C consists of a crosslinking Compound with at least 2 hydroxyl groups. As particularly good Tris (hydroxymethyl) propane proved to be 2,2-bis (4-hydroxyphenyl) propane, Bis (4-hydroxyphenyl) sulfone, hydroxypropyl cellulose or poly dimethylsiloxane diol. The polyols mentioned improve the pickling effect of the metal salts at room temperature and offer the poss possibilities of thermal post-curing through three-dimensional Crosslinking when using trimethoxysilanes containing epoxy groups in component A.

The quantitative relationships of the 3 components to each other and the Solvents can be varied within wide limits. Preferential 20 Ge are based on the respective solids content parts by weight A with 1 to 20 parts by weight B and 1 to 5 Ge parts by weight C mixed. It is convenient to mix the stable components A, B and C only immediately before loading layering process to make a slow viscosity increase in the varnish due to the beginning of crosslinking. The extent of the viscosity increase after mixing is in un different from the concentration and the mixture ratio of components A and B.

The coating of textile and polymeric materials can through all common and known coating techniques such as Padding, dipping, spraying or watering or by relaxing Appropriate impregnation techniques. The layers show Removing the solvent by a drying process (advantageous in a circulating air flow) good mechani properties (hardness, abrasion). If the sub strate are suitable for this, the layer after coating, Gel formation and solvent removal thermally post-cured be tested. For this, the coated object should at least  heated to 80 ° C to 120 ° C. The lower the temperature, the longer the tempering should take place.

The advantages of the coating composition according to the invention are over the previously known coatings:

• 1. Good adhesion and improved mechanical properties properties (hardness, abrasion resistance) of the coated materials after drying at room temperature,
• 2. in the high storage stability of the individual components A, B and C,
• 3. the possibility of a thermal with suitable substrates Perform post-curing,
• 4. in the possibility of changing the mixing ratio component A: B: C the performance characteristics (e.g. hydrophobicity) of the coated materials adapt to the later use,
• 5. Possibility to use the coating agent for special Applications can also be easily modified by before the loading layering special water- or alcohol-soluble substances to be mixed.
• (a) by adding dyes, coloring of the coated textile or polymeric materials, e.g. B. by adding 2-methoxy-4-amino-azobenzene or 4- (3-methylphenylamino) azobenzene can be stable bronze or gold-colored coatings are produced. By adding z. B. from Ethyl violet, brilliant green or rhodamine 6G can be decorated produce active coatings in the colors blue, green and red,
• (b) by adding biocidal substances (e.g. boric acid, benzoic acid right, quaternary ammonium salts, colloidal silver or silver vers bonds based on chemical, thermal or photolytic Path in the layer can be converted into colloidal silver) layers with a biocidal effect can be produced,
• (c) magnetic materials can be produced by adding nanoparticulate magnetic ferrite particles (γ-Fe ₂ O ₃ ),
• (d) by adding 1-20 parts by weight of alcohol-soluble natural resins, e.g. B. from rosin, shellac or copal, based on the solids content, you can increase the barrier effect of the coatings against gases (O ₂ , CO ₂ ) and volatile organic substances (z. B. volatile hydrocarbons).

The applications of the paints are due to the good Stability and the excellent mechanical layer properties very diverse. The coating compositions are particularly suitable for mechanical and chemical protection of textiles and polyme materials, but also to protect objects from tem temperature-stable materials such as metal or glass.

Specific uses of the coating agent are textile dyes exercises with high color fastness, to protect textiles against about ultraviolet radiation; to equip textiles with microwave absorbing or reflecting or IR absorbing or reflecting properties; to the sheep treatment of textiles and polymers with improved wear resistance properties (e.g. manufacture of abrasion-resistant seat textiles); for hydrophobizing fibers and polymer surfaces and ver improvement of the dirt-repellent effect as well as the creation of Textiles with magnetic properties.

Embodiments 1. Preparation of component A

A1: To a mixture of 27 ml tetraethoxysilane (TEOS), 9 ml 3-glycidyloxypropyltrimethoxysilane (GLYMO), 60 ml ethanol added dropwise to the 8 ml 0.01N HCl and 20 hours in the room temperature stirred. A water-clear, stable sol is formed.

A2: To a mixture of 27 ml TEOS, 27 ml dimethyl diethoxy silane (DDS), 18 ml GLYMO, 60 ml ethanol, 15 ml 0.01N HCl added dropwise in 60 ml of ethanol and ge for 20 hours at room temperature stirs. A water-clear, stable sol is formed.

A3: To a mixture of 70 ml tetraethoxysilane (TEOS), 30 ml Methyltriethoxysilane, 420 ml 96% ethanol, 20 ml 0.01N HCl  added dropwise and stirred for 20 hours at room temperature. A water-clear, stable sol is formed.

A4: To a mixture of 27 ml TEOS, 3 ml Trideca-fluoroctyl triethoxysilane, 120 ml ethanol, 8 ml 0.01N HCl dropwise se added and stirred for 20 hours at room temperature. It arises a water-clear stable sol.

2. Production of the coating agent (BS)

By mixing the components listed in Table 1 immediately before coating to a homogeneous sol:

Table 1

Composition of the coating agent

component
B1 = 10% Al ₂ (OH) ₅ Cl × 2-3 H ₂ O in 80% ethanol
B2 = 10% ZrOCl ₂ × 8 H ₂ O in 50% ethanol
component
C1 = bis (4-hydroxyphenyl) sulfone
C2 = 1,1,1-tris (hydroxymethyl) propane
C3 = polydimethylsiloxanediol / Hüls AG, 5% in ethanol
C4 = hydroxypropyl cellulose (Klucel H / Aqualon)

3. Applications of the coating compositions 3.1. Coating a polyester fabric

A technical polyester fabric (polyethylene terephthalate) is dip-coated with the coating solutions I and II (two-roll pad, 0.5 m / min roll speed). After drying, tensile strength tests are carried out on 2 × 6 cm ² strips. The strips are stretched lengthways until they tear.

The maximum pulling force is:
untreated 1292 N
coated with I 1692 N
coated with II 1796 N

3.2. Coating of a technical polyamide fabric

A technical polyamide fabric is made with Soles II and III analogous to 3.3. dip coated and tested.

The maximum pulling force is:
untreated 1170 N
coated with II 1384 N
coated with III 1400 N

3.3. Coating of polycarbonate sheets

Polycarbonate sheets in A4 format were made after a plasma Pretreatment in a high vacuum with coating solutions I-VIII dip-coated (drawing speed 30 cm / min). After Drying result in crystal-clear, abrasion-resistant coatings, which in the case the coating solutions IV and VII a strong water and Show dirt-repellent effect.

3.4. Coating of polymer films

140 µm Oellulose acetate film or 100 µm polyester film with 70 mm width was in a continuous pouring machine LBM 70 / MABA GmbH Wolfen, equipped with cascade pourer, cont coated with coating solutions IX and X only (Pouring speed 1-5 m / min). After drying you get clear, washable yellow or blue film layers.

Claims (14)

1. Coating agent for textile or polymeric materials with the composition:

• (A) a layer-forming organosol, formed by cohydrolysis of tetraalkoxysilanes Si (OR ¹ ) ₄ , trialkoxysilanes R ² Si (OR ¹ ) ₃ and / or dialkoxysilanes R ³ ₂ Si (OR ¹ ) ₂ in an organic solvent,
• (B) an aluminum or zirconium halide in an aqueous organic solvent, and
• (C) a crosslinking compound with at least 2 hydroxyl groups.

2. A coating composition according to claim 1, wherein the solids parts of the components in a ratio of 20 parts by weight A to 1 up to 20 parts by weight B to 1 to 5 parts by weight C. 3. Coating composition according to claim 1 or 2, wherein the component A by cohydrolysis of 10 parts by weight of a tetraalkoxysilane Si (OR ¹ ) ₄ , 0.1 to 10 parts by weight of one or more trialkoxysilanes R ² Si (OR ¹ ) ₃ and / or 0.1 to 5 Share weight of a dialkoxysilane R ³ ₂ Si (OR ¹ ) _{2 is} formed. 4. Coating agent according to one of the preceding claims, wherein R ¹ and R ^{3 are} alkyl radicals with 1 to 4 carbon atoms and R ^{2 is} an alkyl radical with 1 to 18 carbon atoms or a fluoroalkyl radical with 1 to 18 carbon atoms or an epoxy -functionalized alkyl or cycloalkyl radical. 5. Coating agent according to one of the preceding claims che, water-miscible Lö as organic solvent solvents such as low molecular weight alcohols and ketones, cyclic Ethers, alkyl glycols or acetonitrile can be used.   6. Coating agent according to one of the preceding claims che, where component B aluminum hydroxide chloride or zirco is nium oxide chloride. 7. Coating agent according to one of the preceding claims che, the component C from polyhydroxy compounds such as Tris (hydroxymethyl) propane, 2,2-bis (4-hydroxyphenyl) propane, Bis (4-hydroxyphenyl) sulfone, hydroxypropyl cellulose or poly dimethylsiloxane diol exists. 8. Coating agent according to one of the preceding claims surface containing dyes and / or biocidal compounds. 9. Coating material according to one of the preceding claims, which contains nanoparticulate magnetic ferrite particles (γ-Fe ₂ O ₃ ). 10. Coating agent according to one of the preceding claims che, the alcohol-soluble natural resins such as rosin, shellac or copal contains. 11. Coating method using a coating agent according to one of claims 1 to 10 with the method steps:

• (1) preparation of component A by cohydrolysis of Si (OR ¹ ) ₄ and R ² Si (OR ¹ ) ₃ and / or R ³ ₂ Si (OR ¹ ) ₂ in an organic solvent,
• (2) Add components B and C dissolved in aqueous alcohol
• (3) coating a material, and
• (4) drying and curing the layer.

12. The method according to claim 11, wherein the coating by Padding, dipping, spraying, watering or impregnation he follows. 13. The method according to claim 11 or 12, wherein the material is textile or polymeric material.   14. Use of the coating agent according to one of claims 1 to 10 for

• - textile dyeing with high color fastness,
• - to protect textiles against ultraviolet radiation; - To provide textiles with microwave absorbing or reflecting or IR absorbing or reflecting properties;
• - to create textiles and polymers with improved wear properties;
• - For hydrophobizing fibers and polymer surfaces and improving the dirt-repellent effect, and / or
• - to create textiles with magnetic properties.