KR20050018942A - Process for Coating to Obtain Special Surface Effects - Google Patents

Abstract

The present invention comprises a) coating the fibers with a polymer dispersion based on at least one polymer selected from the group of polyurethanes, polyester polyurethanes, polyesters or mixtures thereof, and b) blending the coated fibers with the polymer dispersion to form a coating material. And applying a coating material on the surface to be coated, and c) curing the coating material to form a coating on the surface of the substrate. ; The process according to the invention furthermore comprises A) a solids content of 25 to 90% by weight, a polymer dispersion 5 to 40% by weight based on at least one polymer selected from the group of polyurethanes, polyester polyurethanes and polyesters, B) form 0 to 35% by weight of at least one crosslinking agent, C) 2 to 20% by weight, D) 0 to 20% by weight of solvent, E) 5 to 35% by weight, and selected from the group of aldehyde condensation resins and polyisocyanates, and F) a coating material applied on a substrate surface, optionally comprising 0.5 to 10% by weight of additives, pigments and / or extenders commonly used in connection with coatings.

Description

Process for Coating to Obtain Special Surface Effects

The present invention relates to a substrate coating method for forming a surface having a textile-like texture.

In order to produce a textile or fiber effect on a surface, it is known to process a fiber material with a binder to produce a composite material in which fibers are incorporated into a matrix. For example, DE-A 199 21 209 discloses organic fibers, in particular leather fibers, and matrices, in which a polymer film is subsequently produced by a suitable processing method and the polymer film itself can be applied on the substrate surface by a thermoforming process. Thermoplastic composites containing thermoplastic binders are described.

The fibers can be mixed with a binder to form a fiber nonwoven sheet material or a fiber nonwoven molding. This is described, for example, in WO 95/30034 and WO 96/16218 where organic or inorganic fibers are processed together with a powder binder mixture.

The method described relates to a method for producing a polymer film for substrate coating by thermoforming comprising a fiber material or a method for producing a cured fiber nonwoven sheet material or a fiber nonwoven molding and to a method for producing a textile-like surface formed by substrate coating. It is not.

It is also known to introduce fibers into the mold and inject the polymer to insert the fibers into the molding. Special molds should be used for this purpose; Conventional injection molding molds cannot be used.

It is also known to apply nonwoven fibers on a surface with an adhesive layer and to cure the adhesive to fix the nonwoven fibers on the surface (flocking method). In this method, short chopped textile fibers can be applied onto the adhesive-coated surface using an electrostatic flocking device. When the surface is dried or cured, a surface is obtained having a textile hand that is relatively insensitive to impact and scratching and exhibits good sliding properties for smooth surfaces. The hand of the flocked surface can be varied by appropriately varying the length and fiber thickness of the individual fibers. Fibers that can be used can be, for example, polyamide, biscose or cotton, polyester and carbon fibers. Application of nonwoven fibers can generate dust and cause occupational hygiene and environmental issues. Moreover, conventional adhesives cannot be used to create special surface effects, for example special touch.

Summary of the Invention

The present invention provides a method of coating a substrate surface that gives improved surface effects by overcoming occupational hygiene and environmental issues by simplified treatment and further achieving textile surface finish and soft-feel effect.

The coating method of the substrate surface to achieve the textile surface

a) coating the fibers with a polymer dispersion based on at least one polymer selected from the group of polyurethanes, polyester polyurethanes, polyesters or mixtures thereof,

b) blending the coated fibers with the polymer dispersion to form a coating material and applying the coating material on the surface to be coated,

c) curing the coating material to form a coating on the substrate surface.

In the process according to the invention, loose fiber materials can be blended with the polymer dispersion in such a way that the fibers are fully wetted and coated with the polymer dispersion. Fibers embedded in the polymer dispersion are then applied onto the substrate surface using conventional methods and then the polymer is cured using conventional methods.

The method according to the invention prevents fiber release from the coated surface and thus forms a coating with improved surface properties. By varying the layer thickness of the coating in the manner according to the invention, various optical effects can be obtained, for example textile-like textures.

Fibers usable in the present invention include nonwoven hybrid fibers, which may consist of known materials, such as natural fibers, synthetic fibers, organic fibers and inorganic fibers. Examples are glass fiber, rock wool fiber, polyester fiber, acrylic resin fiber, polyolefin fiber, wool fiber, cotton fiber, linen fiber, leather fiber and the like. Textile fibers, in particular cotton fibers, for example waste fibers of the textile industry are preferably used.

The polymer dispersions used in the process according to the invention are based on polyurethane resins, polyester polyurethane resins, polyester resins, or mixtures of these resins; Preferably, polyurethane resins are used.

Polymer dispersions used in the present invention can be prepared, for example, by mixing or dispersing or dissolving the polymer with an organic solvent or water, for example by thoroughly dispersing the polymer, optionally neutralized with water. An aqueous phase, optionally containing a neutralizing agent, may be initially introduced and the polymer may be incorporated by stirring. A continuous process is also possible, ie the polymer, water and neutralizing agent are mixed uniformly at the same time in known devices such as, for example, rotor / stator mixers. The use of elevated temperatures can also facilitate the conversion to an aqueous phase.

Polyester polyurethane resins and polyurethane resins can be prepared, for example, by reacting linear or branched polyol components, for example diols, with one or more organic polyisocyanates, preferably diisocyanates, using known methods. . Polyols include polyols familiar to those skilled in the art, and polyols having three or more functionalities can be added for branching of the polymer. Suitable polyols are, for example, low molecular polyols such as diols, triols, polyols such as ethylene glycol, propanediol, 1,6-hexanediol, 1,2-cyclohexanediol, bisphenol A and mixtures thereof . Diols derived from fatty alcohols can also be used. Further examples of polyols may be polyether polyols and polyester polyols. The polyether polyols can be represented, for example, by the general formula of HO- (CHR ⁴ ) _{n -m} OH, wherein R ⁴ is the same or different and is hydrogen, optionally C ₁ to C ₆ alkyl having various substituents N is from 2 to 6 and m is from 10 to 50 or more. Polyester polyols can be prepared, for example, by esterifying organic dicarboxylic acids or anhydrides thereof with organic polyols. Dicarboxylic acids and polyols may be aliphatic, cycloaliphatic or aromatic dicarboxylic acids and polyols. The dicarboxylic acid may be a long chain dicarboxylic acid having 18 to 60 chain carbon atoms. The polyester preferably has a molecular weight of 300 to 6000, an OH value of 20 to 400 and an acid value of less than 3, preferably less than 1. Polycarbonate diols may also be used as polyols, as are polyester polyols derived from lactones. These products are obtained, for example, by reacting epsilon-caprolactone with diols, and these polylactone polyols are characterized by the presence of terminal hydroxyl groups and by repeating polyester residues derived from lactones. The lactones can be, for example, any desired lactones having 6 to 8 ring carbon atoms or any desired combination of different lactones.

Further compounds usable as polyol components are, for example, OH- and / or SH-containing polythioethers, OH-containing polyacetals, polyether-esters, OH-containing polyester-amides and polyamides, dihydroxy Polyester carbonates, polyurethane diols, poly (meth) acrylate polyols, polybutanediene oil diols and hydroxy-functionalized siloxane copolymers. Linear polyester polyols and polyether polyols are preferably used.

As the organic polyisocyanate, any aliphatic, cycloaliphatic or aromatic isocyanates such as diisocyanates can be used, as well as sterically hindered isocyanates which may contain, for example, ether groups or ester groups. Polyisocyanates which exhibit higher isocyanate functionality than previously described, for example polymeric polyisocyanates, may be used. Preferred isocyanates are those containing from about 3 to about 36, in particular about 8 to 15 carbon atoms. Examples of suitable diisocyanates are hexamethylene diisocyanate, toluylene diisocyanate, isophorone diisocyanate, hexane diisocyanate. Oligomeric diisocyanates are preferred.

Examples of polyurethanes and polyester polyurethanes are Bayhydrole from Bayer AG, for example Bayhydrol® LS 2244 and Bayhydrol® LS 2305.

Polyester can be prepared in a conventional manner. Polyesters containing carboxyl groups and polyesters containing hydroxyl groups can be used or polyesters without these functional groups can be used. The amount of carboxyl group and hydroxyl group can be adjusted by appropriate selection of the kind and amount of initial component. The polyols used in the preparation of the polyesters are for example diols or higher-functional types or mono and higher-functional OH-components such as trimethylol propane, pentaerythritol, glycerol, polyether polyols. Mixture. The acid component of the polyester is preferably a low molecular dicarboxylic acid having 2 to 18 carbon atoms or an anhydride thereof, such as phthalic acid, terephthalic acid, adipic acid, sebacic acid, maleic acid, itaconic acid, 1, It consists of 4-cyclohexane dicarboxylic acid. If present, methyl esters may also be used. Apart from this, also some of the higher-functional carboxylic acids, for example alkyl-substituted dicarboxylic acids such as tri-functional carboxylic acids such as trimellitic acid, dimethylolpropionic acid or butyl isophthalic acid Acids can be used. The average molecular weight Mn (measured using polystyrene as a calibration material) of suitable polyester resins is, for example, in the range from 1000 to 6000.

Various types of compounds may be used alone or as a mixture of two or more thereof.

If the polymers according to the invention contain ionizable groups, the groups are converted, in whole or in part, to the corresponding salts using suitable compounds, for example neutralizing agents, and the compounds used for salt formation are chemically synthesized during the synthesis. Care must be taken to select inactive compounds. Ion-forming groups that may be present are those capable of forming anions. In this case, bases such as amines, preferably tertiary amines such as trialkylamines, are used for the conversion to anions. If the polymer contains a cation-forming group, preferably one or more acids can be used to form the ions. Suitable acids are, for example, phosphoric acid or acidic phosphoric acid esters or organic carboxylic acids, hydroxycarboxylic acids or dicarboxylic acids. Mixtures of acids may be used. Groups which can form an anion are a carboxyl group, a phosphoric acid group, and a sulfonic acid group, for example. Basic groups convertible to cations that can be considered are, for example, primary, secondary and tertiary amino groups or onium groups such as quaternary ammonium, phosphonium and / or tertiary sulfonium groups.

The polymers usable according to the invention can be used dissolved or mixed in a solvent. Solvents that can be used are water-miscible solvents or water-immiscible solvents. Examples of suitable solvents are monohydric or polyhydric alcohols, glycol ethers or esters, glycols, ketones, aromatic or aliphatic hydrocarbons, alkylpyrrolidones, ethers, and cyclic urea derivatives.

The solvent-free or solvent-containing polymer composition according to the present invention can be converted to the aqueous phase by adding a sufficient amount of water. A finely divided binder composition is then obtained having an average particle size, for example, greater than 10 to less than 2000 nm, preferably greater than 50 to less than 500 nm. Solids content is 25 to 90% by weight, preferably greater than 35 to 60% by weight.

Although it is generally not necessary to use an emulsifier to convert the polymer into an aqueous dispersion in the present invention, an emulsifier may be used. Examples of emulsifiers are ionic or nonionic emulsifiers that promote emulsification and optionally reduce the number of ionizable groups.

The solvent optionally present in the polymer composition according to the invention can be removed if necessary, for example by distillation under reduced pressure.

The polymer dispersion may be self-curing / physical dried or externally crosslinked.

The polymer dispersions may optionally contain crosslinkers, pigments, additional binders and additives with a quantity of solvent.

Various crosslinkers such as blocked polyisocyanates as well as formaldehyde condensation resins such as phenol / formaldehyde condensation resins and amine / formaldehyde condensation resins can be used. Amino resins suitable as crosslinkers are, for example, alkylated condensation products prepared by reacting aminotriazine and amidotriazine with aldehydes. Examples of such resins and their preparation are described in Houben-Weyl, Methoden der organischen Chemie, 663, page 355. Blocked polyisocyanates can also be used as crosslinking agents. These are any desired reactions where the isocyanate groups react with the compound in such a way that the resultant blocked polyisocyanates are resistant to hydroxyl groups and water at room temperature but for example react at elevated temperatures in the range of about 90 ° C to about 250 ° C. Polyisocyanates. It is also possible to use non-blocked polyisocyanates. Aliphatic, cycloaliphatic or aromatic isocyanates as well as sterically hindered isocyanates can be used, and polyisocyanates containing ether groups or ester groups, for example diisocyanates, can also be used. Preferred isocyanates are those containing from about 3 to about 36, in particular about 8 to 15 carbon atoms. Examples of suitable diisocyanates are hexamethylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, hexane diisocyanate. Oligomeric diisocyanates are preferred. Polyisocyanates with greater isocyanate functionality than those described above, for example polymeric polyisocyanates, may also be used.

Crosslinkers can be used individually or as a mixture.

The polymer dispersions according to the invention may also contain one or more additional binders. This may be advantageous, for example, in achieving any synergistic effect. Examples of further binders are conventional film-forming resins familiar to those skilled in the art, for example polyacrylate resins and / or other polyurethane resins. The resin can be reactive or non-functional.

The polyacrylate may contain free carboxyl groups and may be, for example, acrylic or methacryl copolymers. The amount of resin added may be 0 to 50% by weight, preferably 0 to 25% by weight of the total resin solids content. The term "resin solids content" means the total amount of all binders except the crosslinker content.

The polymer dispersions used according to the invention may contain additives such as rheology agents, thickeners, precipitation inhibitors, planarizers, light stabilizers, antifoams, wetting agents and coupling materials.

The catalyst can optionally be used to promote curing. However, it is also possible to cure with thermal energy without using a catalyst.

Suitable solvents that may be present are conventional coating solvents derived from the preparation of the binder or added separately. Examples of such solvents are monohydric or polyhydric alcohols, glycol ethers or esters, glycols, ketones, aromatic or aliphatic hydrocarbons, alkylpyrrolidones, ethers, and cyclic urea derivatives. The evaporation behavior of the coating composition is influenced by the breaking point of the solvent mixture used, while the flow and viscosity of the coating composition is influenced by the choice of solvent.

The polymer dispersions used in the present invention may contain one or more inorganic and / or organic color- or special-effecting pigments and optionally, further extenders. Examples of special effect-pigments are metal pigments such as aluminum, copper or other metal pigments, interference pigments such as metal oxide coated metal pigments, coated mica and graphite special effect pigments. Examples of color-imparting pigments and extenders are titanium dioxide, iron oxide pigments, carbon black, silicon dioxide, barium sulfate, talc, kaolin, chalk, azo pigments, phthalocyanine pigments. Most of the pigments can be incorporated into the coating composition using conventional methods. Special effect-imparting pigments can be incorporated, for example, in the form of conventional commercially available aqueous or non-aqueous pastes. Colorants or extenders can be incorporated, for example, by grinding on a portion of the aqueous binder, and the grinding can also be carried out in special water-dilutable paste resins.

Coating materials based on polymer dispersions and fiber materials according to the invention

A) 5 to 40% by weight of a polymer dispersion having a solids content of 25 to 90% by weight and based on at least one polymer of polyurethane, polyester polyurethane and polyester,

B) 0 to 35% by weight of one or more crosslinkers, selected from the group of formaldehyde condensation resins and polyisocyanates,

C) 2 to 20% by weight of fiber material,

D) 0 to 20% by weight solvent,

E) 5 to 35% by weight of water, and optionally

F) 0.5 to 10% by weight of additives, pigments and / or extenders commonly used in connection with coatings.

The coating material according to the invention can be applied using conventional methods and is preferably applied by spraying to a dry film thickness of 8 to 500 μm. Application is preferably carried out using a wet-on-wet process, for example drying or crosslinking at a temperature of 20 to 140 ° C.

The coating material according to the invention can be used in multi-layer coatings, for example overcoated with a clear coat. Suitable clear coats are in principle any known clear coats or clear pigmented coating compositions. The coating composition used in the present invention can be used as a transparent coat with or without a transparent pigment. Solvent-containing one-component or two-component coating compositions as well as water-dilutable transparent coats, powder transparent coats or radiation-curable transparent coats may also be used.

Multi-layer coatings can be applied on the substrate in various ways. For example, a plastic primer is provided on a plastic substrate, on which the polymer dispersion according to the invention can be applied and cured. The polymer dispersions according to the invention can also generally be wet-on-wet applied onto the non-crosslinked filler layer and then baked together with the filler layer prior to application of the transparent top coat.

It is also possible to apply the coating material according to the invention directly onto the substrate without further interlayers.

The coating material according to the invention can also be used as an aqueous top coat, for example applied on a color-imparting base coat in a multi-layer coating. Suitable substrate coats are in principle any known substrate coats. Solvent-containing one-component or two-component coating compositions as well as water-dilutable substrate coats or radiation-curable substrate coats may be used. Such multi-layer coatings can be similarly applied on a substrate in a variety of ways. A plastic primer is applied to the plastic substrate, on which the substrate coat layer can be applied and cured. In general, prior to application of the transparent top coat, the substrate coat can be wet-on-wet applied onto the non-crosslinked filler coat and then baked together with the filler coat, on which the polymer dispersion according to the invention can be applied and cured. have.

Suitable substrates for coating with the coating material according to the invention are substrates made of metals, plastics, concrete, wood and films (plastic films, paper sheets), in particular plastic automotive parts, in particular plastic parts for automotive interiors.

Very good interlayer adhesion is achieved in the production of multi-layer structures. Multi-layer coatings according to the invention meet the usual recent requirements which are added to automotive coatings in plastic coatings, especially in automotive part coatings.

The invention furthermore relates to a substrate coated with the coating material according to the invention, optionally in conjunction with a multi-layer system, and to drying or curing of the coating on the substrate.

Multi-layer systems preferably apply one or more primer coats based on the water-dilutable coating composition, apply a color-imparting substrate coat layer comprising the coating material according to the invention, optionally dry the substrate coat and top It can be obtained by applying a clear coating composition as a coat and subsequently heating the coated substrate. Additional layers may optionally be added to the multi-layer coating. Primer coats may also be omitted.

Multi-layer systems also preferably apply one or more primer coats based on water-dilutable coating compositions, apply conventional color-imparting substrate coat layers, optionally dry the substrate coat and according to the invention as a top coat. It can be obtained by applying a clear coating composition comprising a coating material and subsequently heating the coated substrate. Additional layers may optionally be added to the multi-layer coating. Primer coats may also be omitted.

Multi-layer coatings according to the invention exhibit good surfaces with very good interlayer adhesion. In particular, it is possible to achieve surface finishes with a fairly smooth appearance using the coating material according to the invention, which finishes are particularly suitable for finishing automotive plastic part surfaces inside automobiles. Moreover, substrates treated with multi-layer coatings meet the usual recent-requirements for plastic coatings, especially plastic parts inside automobiles, for example multi-layer coatings exhibit significant resistance to condensation and adhesion. There is no loss.

Substrates coated using the method according to the invention can be used for a wide variety of purposes. For example, it is possible to use the method according to the invention for coating substrates used for insulation purposes, ie for thermal insulation as well as sound insulation. The method according to the invention can furthermore be used to impart various requirements to the substrate in soundproofing properties, for example to achieve any soundproofing behavior. Finally, the method according to the invention can be used to provide an attractive, decorative finish on the substrate surface and can be used to achieve any tactile properties, for example a smooth appearance. Substrates coated using the method according to the invention are easily cleanable and durable, ie exhibit an extended service life of the coating while maintaining the desired properties.

The following examples illustrate the invention. All parts and percentages are by weight unless otherwise indicated.

With stirring, 30% by weight of a given OH-functional polyurethane dispersion based on Bayhydrol® LS 2305, 3% by weight of degassing agent, 6% by weight of polysiloxane solution as flow promoter, based on Bayhydrol® LS 2305 20% by weight of one OH-functional polyurethane dispersion and 3% by weight of acrylate thickener were added. After a homogeneous mixture was obtained, 15% of 0.5-2 mm long viscose fibers were sprinkled onto the mixture in fractions. To adjust the viscosity of the mixture, 15% by weight of deionized water was added while stirring. Subsequently the material was homogenized for about 20 minutes.

Precisely prior to the application process, 15% by weight (solid content: 12-25% by weight) of HDI-solution (hexamethylene diisocyanate solution) as a curing agent was added and homogenized to the polyurethane dispersion components prepared above within 10 minutes at 1000 rpm. .

Subsequent application processes consisted of three to four cross-coat spraying steps on the plastic surface.

A coating with a felt-like surface and a stable appearance as well as smoothness was obtained and there was no release of fibers from the surface of the coating.

Claims (13)

a) coating the fibers with a polymer dispersion based on at least one polymer selected from the group consisting of polyurethanes, polyester polyurethanes, polyesters and mixtures thereof, to form coated fibers, b) blending the coated fibers with the polymer dispersion to form a coating material and applying the coating material on the surface of the substrate to be coated, c) curing the coating material to form a textured surface on the substrate. The method of claim 1 wherein the coating material a) 5 to 40 weight percent polymer dispersion based on at least 25 to 90 weight percent solids, based on at least one polymer selected from the group consisting of polyurethanes, polyester polyurethanes, polyesters and mixtures thereof, b) 0 to 35% by weight of one or more crosslinkers, selected from the group consisting of formaldehyde condensation resins and polyisocyanates, c) 2 to 20% by weight of fiber material, d) 0 to 20% by weight solvent, e) 5 to 35% by weight of water, and optionally f) 0.5 to 10% by weight of a composition selected from the group consisting of coating additives, pigments, extenders and any mixtures thereof. The method of claim 1 or 2, wherein the polymer is polyurethane. The method of claim 1, wherein the fibrous material is selected from the group consisting of polyacrylic fibers, viscose fibers, cotton fibers and polypropylene fibers. One or more layers are essentially a) 5 to 40% by weight of a polymer dispersion, having a solids content of 25 to 90% by weight and based on at least one polymer selected from the group consisting of polyurethanes, polyester polyurethanes and polyesters and mixtures thereof, b) 0 to 35% by weight of one or more crosslinkers, selected from the group consisting of formaldehyde condensation resins and polyisocyanates, c) 2 to 20% by weight of the fiber material coated with the polymer dispersion, d) 0 to 20% by weight solvent, e) 5 to 35% by weight of water, and optionally f) a coating composition consisting of 0.5 to 10% by weight of a composition selected from the group consisting of coating additives, pigments, extenders and any mixtures thereof, comprising applying a substrate coat layer and a transparent coat layer and curing the layers Method of forming a multiple coating layer on a substrate. The method of claim 5 wherein the polymer is polyurethane. The method of claim 5 wherein the fibrous material is selected from the group consisting of polyacrylic fibers, viscose fibers, cotton fibers and polypropylene fibers. 6. The method of claim 5 wherein the coating composition comprises a substrate coat containing 0.5 to 10 weight percent pigment. The method of claim 5, wherein the coating composition comprises a transparent coat. 10. The method of claim 9, wherein the transparent coating composition contains 0.5 to 10 weight percent of the transparent pigment. The method of claim 1, wherein the substrate is selected from the group consisting of metal, plastic, concrete, wood, plastic film, and paper film. A substrate coated and cured by the method according to claim 1. The substrate of claim 12, wherein the substrate is a plastic component inside an automobile.