DE102004039708A1 - Foamed polymers and foam-coated textile fabrics - Google Patents

Abstract

Highly concentrated aqueous polyurethane dispersions are converted into stable foams. Textile fabrics which are coated with these foams are suitable, inter alia, for darkening glass panes.

Description

The Invention relates to stable foams, those from highly concentrated aqueous Polyurethane dispersions are produced. It also concerns the use of such foams for the production of foam-coated textile fabrics, which in turn for the production of darkening materials or Serve decoration materials.

foam Coated Tissues are known. This is among others from US-A 3,713 868 forth. In this document, tissues are described which coated with a foam containing acrylate. These Tissues are not suitable or only very limited for the darkening materials described below and decorative materials, because they either too low or have too high adhesion to flat glass surfaces or ceramic surfaces. If the tissues are placed on smooth glass surfaces, e.g. window panes by pressing them against the glass surface with light pressure, so they can be in many cases after some time no longer residue-free from the glass surface remove.

The WO 01/85 863 A1 also describes foam-coated fabrics, wherein the foam may include polyurethane among other things. Those ones mentioned products can with an outer layer be made of an adhesive to give adhesion to others Effect materials. The preferred use of the tissue consists in the production of adhesive tapes, which one more on the foam-coated fabric additionally applied layer made of adhesive. about the concentration of the aqueous Polymer dispersion from which the foam is obtained makes them Scripture no statement. The foam with which the fabric coats is not generated before the application of the coating, but forms in situ on the tissue. The articles mentioned in this document opposite smooth glass surfaces not the necessary ones Adhesive and release properties (as described below) on and are therefore not as darkening materials for window panes or only partially suitable.

Of the present invention had the object of providing a method for Produce a stable foam to provide a foam to obtain, with which to coat textile fabric, which subsequently very good for use as blackout materials or decoration materials are suitable.

The Task has been solved by a process for producing a stable foam with a Foamiter weight of 150 - 350 g / L, wherein a stable aqueous Dispersion containing 50 to 70% by weight of a polyurethane or mixture of polyurethanes, foamed.

through of the method according to the invention stable foams produced. This means that the foams when standing in the air and do not disintegrate within 1 minute if air enters.

The according to the inventive method produced foams have a foam weight in the range of 150 to 350 g / l at Room temperature. The foam weight is determined by into a measuring vessel with volume scale gives a certain amount of foam, determines the volume of this foam and the weight of this foam amount determined by weighing.

Foams with a Schaumlitergewicht in said range can be obtained by using the parameters to those as foam generators used, controls equipment accordingly. Commercially available foam generators like those mentioned below have appropriate control options.

The foams are produced by means of the process according to the invention by foaming an aqueous dispersion. This dispersion must contain 50 to 70% by weight of a polyurethane or a mixture of polyurethanes. Normally, the polyurethane used is not self-dispersing, so that the aqueous dispersion usually also contains one or more dispersants. As dispersants known surface-active products can be used, such as ethoxylated fatty alcohols. It is also possible to use ionic or amphoteric surfactants frequently, provided that a stable aqueous dispersion results. In this context, a stable aqueous dispersion is to be understood as meaning a dispersion which has no precipitations or phase separation after a storage time of 3 months at room temperature. Polyurethanes which are suitable for the process according to the invention are available on the market. However, only those polyurethanes are suitable from which stable aqueous dispersions can be obtained. containing 50 to 70% by weight of the polyurethane in question and from which stable foams can be prepared as defined above. Polyester polyether polyurethanes are preferably used for the process according to the invention, in particular aliphatic polyester polyether polyurethanes, ie polyurethanes which contain no aromatic, cyclic or unsaturated units. Such polyurethanes contain in addition to urethane units and ester units Ethereinheiten and are also available in the market.

The Preparation of aqueous Dispersions containing 50 to 70% by weight of a polyurethane or a mixture of polyurethanes can, according to customary, known in the art, Methods are done. It can e.g. submitted an aqueous surfactant solution in which then a polyurethane is dispersed, normally using shear forces (Stirrer) and optionally at elevated temperature.

finished aqueous Polyurethane dispersions having a solids content of 50 to 70 Weight% are also also available in the market.

An example of a very suitable polyurethane dispersion is the product DICRYLAN ^® 7753 or DICRYLAN ^® PGS Ciba Specialty Chemicals Pfersee GmbH, DE. Furthermore, suitable polyurethanes or polyurethane dispersions in IMPRANIL ^® series (Bayer AG, DE) to find.

Of the pH of the aqueous Dispersion is preferably in the range of 7.5 to 10 at 20 ° C. To adjustment the pH value is well suited an aqueous ammonia solution.

• A eine wässrige Lösung ist, die 40 bis 70 Gew%, vorzugsweise 45 bis 65 Gew%, eines veretherten Tetra-, Penta- oder Hexamethylolmelamins enthält,
• B eine wässrige Zusammensetzung ist, die 10 bis 25 Gew% eines Alkalimetall- oder Ammoniumstearats und 70 bis 90 Gew% Wasser enthält,
• C eine wässrige Dispersion ist, die 20 bis 40 Gew% eines Copolymeren aus (Meth)acrylsäure und einem (Meth)acrylsäureester mit 2 bis 6 Kohlenstoffatomen in der Alkoholkomponente enthält, wobei die Dispersion pro 1000 Gewichtsteilen an Polyurethan die Komponenten A, B und C vorzugsweise in folgenden Mengen enthält 20 bis 50 Gew.teile A 50 bis 200 Gew.teile B 3 bis 20 Gew.teile C

A preferred embodiment of the method according to the invention is characterized in that the aqueous dispersion additionally contains one or more of the following components A to C, wherein

• A is an aqueous solution containing 40 to 70% by weight, preferably 45 to 65% by weight, of an etherified tetra-, penta- or hexamethylolmelamine,
• B is an aqueous composition containing 10 to 25% by weight of an alkali metal or ammonium stearate and 70 to 90% by weight of water,
• C is an aqueous dispersion containing from 20 to 40% by weight of a copolymer of (meth) acrylic acid and a (meth) acrylic ester having from 2 to 6 carbon atoms in the alcohol component, wherein the dispersion contains components A, B and C per 1000 parts by weight of polyurethane preferably in the following amounts contains 20 to 50 parts by weight of A 50 to 200 parts by weight of B 3 to 20 parts by weight of C

component A is preferably an aqueous one Solution, which 45 to 65% by weight of a etherified with methanol or ethanol Pentamethylol melamine contains. It causes better adhesion of the coating on fabrics and increases the permanence of the fabric Effects. Component B acts as a stabilizer and as a foam generator.

component C acts as a thickener.

Suitable components A, B and C are available on the market products such as the products LYOFIX CHN ^® or LYOFIX ° MLF new (component A), DICRYLAN ^® FLN stabilizer (component B) and DICRYLAN ^© -VERDICKER HV 30 or DICRYLAN ^® - VERDICKER R (component C) from Ciba Spezialitätenchemie Pfersee GmbH, DE.

Further can the dispersions which serve to generate foam, dyes or pigments.

The Production of stable foams from the said aqueous Dispersions can be prepared by well-known methods in known Devices take place. It is suitable, e.g. a foaming by means Mixing with air. The foaming can be in commercial Foam generators performed as described by Hansa, e.g. "Hansa Industrial Mixer Top-Mix-K" or Stork, NL, e.g. FP III (Foam Processor) can be obtained.

The according to the inventive method produced foams are good for the foam coating of textile fabrics. These fabrics can Being woven, knitted or nonwovens. Preferably, they are Tissue. The fabrics can natural or contain synthetic polymers and are preferably made of polyester, Polypropylene, polyacrylonitrile, cellulose, polyamide or mixtures of these Polymers. They are particularly suitable for the production of darkening materials or decoration materials of the type explained below for level Surfaces. These blackout or decoration materials are on with Foam coated side opposite flat glass surfaces self-adhesive, so do not require an additional layer of adhesive.

Under Darkening materials are foam-coated in this context textile fabrics understood, which cause the light transmittance one completely or partially transparent material having a substantially even surface is reduced after applying the fabric to this material Has. Such complete or partially transparent materials onto which the foam-coated textile fabrics can be applied for the purpose of darkening, e.g. Plastic films or Be plexiglass. Particularly suitable are flat glass panes, such as. Slices of window glass, such as those in buildings or Cars are used.

The reduction of light transmission In this case, it may assume an extent that the material obtained, for example a glass pane to which the foam-coated textile fabrics have been applied, is practically impermeable to visible light. In this case, they are so-called "black-out" materials, or there is still some light transmission, which is called "dim-out" materials. In any case, the light transmission is significantly reduced. Whether the articles obtained correspond to "black-out" materials or "dim-out" materials, it is possible to control the type and amount of foam applied to the fabric and the nature and thickness of this fabric itself. It is also it is possible to apply to the textile fabric several layers of the stable foam in successive operations, eg to achieve a desired higher layer thickness.

The textile fabrics, on which foams were applied, which were prepared by the process according to the invention were very suitable as darkening materials or decorative materials for im essential flat surfaces.

These Materials are applied using a light pressure, normally enough light pressure by hand, applied to the flat surface. Find here among other things as darkening material in the form of light or glare protection, especially for glass surfaces such as window glass or car glass, use or as decorative material, e.g. For Tiles in kitchens or bathrooms. In the case of decorative materials can the after the method according to the invention foams produced a dye or pigment added be. It is also possible, that the textile fabric to be coated is printed or dyed.

The coated with the foam and then dried as described textile fabrics also fit well on floors Apply the most diverse materials and adhere well to these. An application of this fact can Non-slipping puzzle pieces designed by children on floors become.

The with the foams coated textile fabrics are available on many materials such as Self-adhesive glass sheets, i.e. they adhere well after applying a light contact pressure. They can also easily be replaced by the flat surface Remove peel off leaving no residue on this surface. Thus, these foam-coated fabrics can be not just once, but many times.

• a) sie sind billiger herzustellen
• b) sie erfordern keine Installation, welche bei Lamellen ziemlich aufwendig sein kann
• c) sie eigenen sich auch für schräge, d.h. nicht vertikale Oberflächen, wo Lamellen versagen, deren Wirkung schwerkraftabhängig ist.

Compared to conventional blackout fabrics for window panes, which consist for example of slatted curtains, the foam-coated textile fabrics according to the present invention have one or more of the following advantages:

• a) they are cheaper to produce
• b) they require no installation, which can be quite expensive in lamellae
• c) they are also suitable for oblique, ie non-vertical surfaces where lamellas fail whose effect is gravity-dependent.

• 1. Die wässrigen Dispersionen, aus welchen nach dem erfindungsgemäßen Verfahren Schaum erzeugt wird, müssen Polyurethane in einer Konzentration von 50 bis 70 Gew% enthalten, und sie müssen stabil sein. Aus diesen Bedingungen ergibt sich, dass nicht alle Polyurethane für das erfindungsgemäße Verfahren geeignet sind. Ob ein bestimmtes Polyurethan geeignet zur Herstellung solcher Dispersionen ist, lässt sich durch wenige Versuche ermitteln.
• 2. Die nach dem erfindungsgemäßen Verfahren hergestellten Schäume müssen stabil sein, wie oben erläutert.

In order to obtain the mentioned properties of the foam-coated textile fabrics, namely on the one hand good adhesion to flat glass surfaces and on the other hand residue-free removability by peeling. several conditions must be fulfilled:

• 1. The aqueous dispersions from which foam is produced by the process of the invention must contain polyurethanes in a concentration of 50 to 70% by weight, and they must be stable. From these conditions it follows that not all polyurethanes are suitable for the process according to the invention. Whether a particular polyurethane is suitable for the preparation of such dispersions, can be determined by a few experiments.
• 2. The foams produced by the process according to the invention must be stable, as explained above.

• 3. Die Dicke der Beschichtung, welche nach Applizieren eines unten näher definierten Schaums auf ein bestimmtes textiles Flächengebilde und anschließender Trocknung und Kondensation, wie unten beschrieben, resultiert, soll einen Wert von mindestens 0,2 mm, vorzugsweise im Bereich von 0,2 mm bis 3 mm, besitzen.
• 4. Die Dicke der unter 3. genannten Beschichtung sollte nicht um mehr als 10 % geringer werden, nachdem das beschichtete textile Flächengebilde während 5 Minuten einer mechanischen Belastung von 5 kg ausgesetzt war.

It is also of great advantage if, in addition, the following conditions are met:

• 3. The thickness of the coating, which results after applying a foam defined in more detail below to a specific textile fabric and subsequent drying and condensation, as described below, should have a value of at least 0.2 mm, preferably in the range of 0.2 mm up to 3 mm.
• 4. The thickness of the coating referred to in 3. should not be reduced by more than 10% after the coated fabric has been subjected to a mechanical load of 5 kg for 5 minutes.

Whether conditions 3 and 4 can be fulfilled with a particular aqueous polyurethane dispersion can be tested in the following way:
A stable aqueous dispersion is prepared which contains 55% by weight of the polyurethane to be tested and about 5% of suitable nonionic dispersants. 30 parts by weight of component A, 100 parts by weight of component B, 10 parts by weight of component C of the type described above are added to this dispersion per 1000 parts by weight of dispersion. The pH of the composition obtained should be about 9.5 and optionally by addition of aqueous ammonia solution can be adjusted. The resulting composition is foamed to a stable foam having a foam weight of about 200 g / l. Subsequently, the foam is applied to a polyester fabric of about 180 g / m ² . This is followed by drying at 80 ° C / 5 minutes substantially without the effect of increased mechanical pressure and condensation at 150 ° C for 5 minutes. Subsequently, the layer thickness is determined. This determination is made by placing the coated tissue sample between two small, thin, planar glass slides and determining the thickness of the total of glass slides and tissue sample using a Frank thickness gauge. In this measurement, no mechanical pressure is applied to the tissue except for the low weight of the upper glass slide.

Subsequently, will the structure of the two glass slides and the tissue sample in between Loaded for 5 minutes by an overhead weight of 5 kg. After removal of the weight leaves relax for 1 minute and then measure the thickness again after the method described above. From the value of the thickness before loading and the value after loading leaves calculate the percentage decrease of the layer thickness.

Polyurethane dispersions, with which condition 3 and / or 4 can not be fulfilled are for the inventive method less suitable, in some cases even unsuitable.

It has been shown to increase the positive characteristics of blackout or to obtain decorative materials, the coating by means of foam application must be done. A coating in another form, e.g. by means of a usual Paste coating, leads not to the advantages of these materials described above, even then not if for the paste coating the same polyurethanes are used.

When textile fabrics, on which the foam is applied can be made of natural, semisynthetic or synthetic fibers or yarns used become. As natural Fibers or yarns come in particular cotton fibers or yarns into consideration, as semi-synthetic fibers and regenerated yarns Cellulose, as synthetic fibers or yarns of polyester or Polyamide. Also textile fabrics, which mixtures of such fibers contain, are well suited to execution the method according to the invention. As textile fabrics Fabrics, knits or fleeces (nonwovens) are well suited.

The Application of the foam to the textile fabric can according to known Methods and done with known devices. It is preferred here that the stable foam on a textile fabric by coating is applied, the fabric subsequently at a temperature in the range of 70 to 130 ° C substantially without application dried under a mechanical pressure and then substantially without Application of a mechanical pressure at a temperature in the range of 130 ° C up to 180 ° C while a time of 30 to 300 seconds is condensed. Under "Coating of the textile fabric "is to be understood that at least one layer of the stable foam applied becomes. It can but also several layers of the same stable foam in succession be applied, e.g. for the purpose of achieving a higher layer thickness.

One way to apply the foam to the fabric is to apply it with the aid of a roller doctor blade with a knife suitable for foam application, such as a shoe knife or circular blade and with a free gap of 0.2 to 2 mm. Another possibility is the use of a rotary stencil with a suitable mesh number. The amount of foam which is applied to the textile fabric is preferably measured so that, according to the condensation explained below, 20 to 300 g / m ^{2 of} solids deposit on the textile result. The amount used in the individual case depends inter alia on the type of polyurethane and the desired article properties (eg "black-out" or "dim-out").

To the foam application, the fabric is dried, preferably at a temperature in the range of 70 ° C to 130 ° C up to a residual moisture of 5 - 10 %, based on the amount of water contained in the foam used. The textile fabrics should while and after drying and during the condensation (which will be described below) is essentially none exposed to mechanical pressure, so do not be pressed.

To the drying of the textile fabrics We recommend a condensation, so a treatment at higher Temperature. This condensation is preferred at a temperature in the range of 130 to 180 ° C while a time of 30 to 300 seconds.

To the condensation can the foam-coated fabrics to the desired Final articles, e.g. to self-adhesive darkening materials be tailored.

The Invention will now be illustrated by embodiments.

Example 1:

manufacturing a stable foam and its use

The starting material used was an aqueous dispersion which contained an aliphatic polyester-polyether polyurethane and dispersants. The polyurethane and dispersants together formed about 60% by weight of this dispersion. To 1000 parts by weight of this dispersion was added successively with stirring
30 parts by weight LYOFIX ^® CHN
100 parts by weight DICRYLAN ^® stabilizer FLN
20 parts by weight of a 25% aqueous ammonia solution and
10 parts by weight of a 1: 1 mixture of DICRYLAN ^® -VERDICKER HV 30 and water.

The The dispersion obtained had a pH at 20 ° C from about 9.5.

The thus obtained dispersion ("foam compound") was obtained by means of Foam generator FP III (Stork, NL) by mixing with air in a stable foam with a Schaumlitergewicht of about 200 g / l transferred.

The foam thus produced was applied by means of a roller blade with a shoe knife, free gap 0.9 mm, to a polyester fabric with plain weave of 180 g / m ² .

It was then dried at 90 ° C / 5 minutes, followed by condensation at 150 ° C / 5 minutes. The resulting textile fabric had a solids deposit of 100 g / m ² after the condensation. The layer thickness on the textile was 0.3 mm. After the 5 kg load described above, the layer thickness decreased by less than 5%.

The Coated fabric thus obtained became 2 m × 0.4 m huge rectangular pieces tailored. These were applied to window glass by lightly pressing Hand applied. They were self adhesive and stuck well on the glass surface and let even after 3 months by removing by hand residue-free remove. Analogous results were obtained with Plexiglas in place of glass. After peeling off of the textile fabric From the glass and storage of a few days, the textile settled again Apply glass without deteriorating the adhesion properties occurred. This was true even if before re-sticking the textile sheet a household wash at 40 ° C was subjected.

At Place a full-surface Application it is possible the textile fabric to cut to certain patterns such as Easter or Christmas motifs and so on to apply glass.

Example 2

example 1 was repeated, but with the finished fabric not on glass, but as decoration material on ceramic tiles was applied. Again, there was good adhesion and the possibility a residue-free Replacement and Reuse analogously to Example 1.

Claims (10)

Process for producing a stable foam with a foam weight of 150 - 350 g / l, whereby a stable aqueous Dispersion containing 50 to 70% by weight of a polyurethane or mixture of polyurethanes, foamed. Method according to claim 1, characterized in that the polyurethane is a polyester polyurethane, preferably an aliphatic polyester polyether polyurethane. Method according to claim 1 or 2, characterized that the watery Dispersion has a pH in the range of 7.5 to 10 at 20 ° C. Method according to one or more of claims 1 to 3, characterized in that the aqueous dispersion additionally a or more of the following components A to C, wherein A an aqueous one solution is 40 to 70% by weight, preferably 45 to 65% by weight, of an etherified Contains tetra-, penta- or hexamethylolmelamins, B is an aqueous composition is 10 to 25% by weight of an alkali metal or ammonium stearate and Contains 70 to 90% by weight of water, C an aqueous one Dispersion is 20 to 40% by weight of a copolymer of (meth) acrylic acid and a (meth) acrylic acid ester containing 2 to 6 carbon atoms in the alcohol component, in which the dispersion per 1000 parts by weight of polyurethane components A, B and C preferably in the following amounts 20 to 50 parts by weight A 50 to 200 parts by weight B 3 to 20 parts by weight C Use of one according to one or more of claims 1 to 4 produced foam for the production of darkening materials or decoration materials for essentially flat surfaces, these materials are foam-coated fabrics consist. Use according to claim 5, characterized ge indicates that the fabrics are woven, knitted or nonwoven. Use according to claim 5 or 6, characterized that the textile fabrics look like Polyester, polypropylene, polyacrylonitrile, cellulose, polyamide or consist of mixtures of these polymers. Use according to one or more of claims 5 to 7, characterized in that the substantially planar surfaces are glass sheets, preferably panes of window glass. Use according to one or more of claims 5 to 8, characterized in that the stable foam on a textile By fabric Coating is applied, the fabric then at a temperature in the range of 70 to 130 ° C substantially without application of a dried under mechanical pressure and then essentially without application a mechanical pressure at a temperature in the range of 130 ° C to 180 ° C during a Time is condensed from 30 to 300 seconds. Use according to claim 9, characterized that the thickness of the coating after condensation has a value in the range of 0.2 to 3 mm and that the thickness of this coating decreases by less than 10% when coating for 5 minutes subjected to a mechanical load of 5 kg.