CS210523B1 - Soft permeable laminated material - Google Patents

Abstract

The materials of the invention are intended as a substitute for natural leather in industry footwear, clothing and haberdashery, eventually in other areas. Their advantage is that they can be made from aqueous polymer dispersions, i.e. without using organic solvents that is in other procedures it is economically disadvantageous regenerate in large quantities, taking serious losses cannot be avoided environmental impact (toxicity). Another advantage is the possibility choice of a wider range of usable polymers. The essence of the solution that leads to the described benefits, is. that the middle porous layer preparing by dispersing the aqueous dispersion of the mixture based on polyurethanes, polyacrylates or rubber or mixtures thereof dry weight 30 to 65% by weight and addition surfactant in an amount of 0.01 up to 5 parts by weight per 100% by weight parts of the dispersion whose viscosity is adjusted by adding a thickener to 0.5 to 25 PaS.

Description

BACKGROUND OF THE INVENTION The present invention relates to a soft breathable laminate composed of a cover polymer layer, a mid porous polymer layer, and a backing textile layer, which may optionally be impregnated with a polymer. The material is intended for use in the footwear, clothing, haberdashery and other industries as a substitute for natural leathers.

A number of sheet materials for these applications are known from the literature and on the market, predominantly low cost polyvinyl chloride based products and polyurethanes for excellent physico-mechanical properties. If good hygiene properties, ie water vapor permeability and sorption, are required for applications in the clothing industry and especially in the footwear industry, polyurethanes are again preferred in the form of micro-porous layers prepared by solution coagulation.

The disadvantage of precipitation processes is the fact that large amounts of solvents need to be regenerated, which worsens the process economy. A particularly serious disadvantage is that certain losses of toxic solvents cannot be prevented. For these reasons, efforts have been made to prepare porous formations without the use of solvents, for example, from aqueous polymer dispersions which overcome the drawbacks described.

It is known from the patent and company literature to use aqueous polymer dispersions in the production of layered sheet materials both for the formation of cover layers (homogeneous layers), impregnation of underlying textile layers, adhesive (laminating, laminating) layers, and for forming core backing layers, especially porous. ,

The formation of porous layers from aqueous dispersions can be achieved in several ways. E.g. a laminate having a central layer based on polyurethane latex is disclosed. Foaming of the central layer is caused by mixing of the mixture into which an air pressure of 0.6 MPa is blown. Expansion occurs when the mixture enters the free atmosphere. The disadvantage in this case is the need for a special mixing device.

Another patent discloses the application of blowing agents to latexes. However, this method is not suitable for the formation of high-quality porous structures, it only leads to the formation of a torn structure, since the blowing agent only works after the water has evaporated from the dispersion, ie in the plastic state of the polymer.

This, with considerable viscosity and limited deformability, does not allow the formation of a good porous structure. Thus, the addition of a blowing agent to the dispersion is advantageous only for impregnating the textile formations of the dispersions since it increases the breathability of the impregnated form.

Also described is a method of making foam layers by whipping a non-ionic polyurethane dispersion, deposition and drying. This method leads to the best quality structures formed in a solvent-free manner so far, but it requires compliance with relatively narrowly specified conditions.

The dry matter content of the dispersion must be at least 45% by weight, the viscosity must be in the range of 0.2 to 1.2 PaS and the particle diameter in the dispersion must not exceed 1 µm. In this process, emulsion-free dispersions are used with only 0.1-10% by weight thickener.

The purpose of the invention is to find a material which can be manufactured from a substantially larger range of types of ionic and non-ionic dispersions based on polyurethanes, acrylates, rubbers and polyvinyl chloride. It has been found that materials which can be obtained by whipping the aqueous dispersion of the blend on polyurethanes, polyacrylates or rubber or mixtures thereof with a dry matter content of 30 to 65% by weight and the addition of a surfactant in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the dispersion, the viscosity of which is adjusted to 0.5 to 25 PaS by adding a thickener, drying the layer of whipped foam and bonding it to the undercoat.

The preferred dry matter content of the dispersion is greater than 45% by weight. The addition of the filler increases the self-supporting of the porous layer (the foam has less tendency to collapse on drying), so dispersions with a lower dry matter content can also be used. The load limit is up to 30% by weight of dry matter with the possibility of the above-mentioned thickening. It is not appropriate to define the addition of the dispersion thickener by the weight ratio, since each thickener has a different thickening ability but the achieved viscosity of the mixture.

A viscosity of less than 0.5 Pas is difficult to foam to maintain a stable foam. A mixture having a viscosity of more than 25 Pas is difficult to apply after foaming by conventional methods, and further requires an amount of thickener which can adversely affect the properties of the porous layer.

The addition of a surfactant such as ammonium stearate soap is necessary both in terms of foam formation by whipping the dispersion (the addition results in a good, foam-stable foam) and in terms of the stability of the porous structure during drying as well as the quality of the pores obtained. The addition of a surfactant of less than 0.01% by weight per 100% dispersion is not sufficiently reflected and an addition of more than 5% by weight per 100% dispersion has an adverse effect primarily on the hydrolytic stability of the porous film *,

Furthermore, it has been found that it is possible and in many cases advantageous to use a filler for the dispersion of the carrier layers of the laminates. All common fillers can be used, eg ground chalk, ground or precipitated limestone, kaolin, bentonite, etc. The filler addition can be used for any base dispersion, but is only required for dispersions with a dry matter content of less than 40% by weight for reasons mentioned above. foam collapsing on drying. The addition of a filler less than 0.01 parts by weight per 100 parts by weight of dispersion does not affect the porosity of the porous layer; addition of more than 30 parts by weight per 100 parts by weight of the dispersion results in deterioration of the physical properties of the porous layer.

It has also been found that the rheology of the foaming system based on aqueous polymer dispersions as well as the time stability of the wet foam, the stability of the foam on drying and the properties of the dried porous layer can be positively influenced by the addition of a crosslinker. which may be partially etherified. The addition of less than 0.01 parts by weight per 100 parts by weight of the dispersion has a negligible effect on the above parameters. The addition of greater than 20 parts by weight per 100 parts by weight of the dispersion limits the flexibility of the porous film to such an extent that the material is unusable for the desired applications.

The described core backing layers can be combined with any cover layer (polyvinyl chloride, polyurethanes, polyamides, etc.) as well as any backing layer (fabric, knitted fabric, nonwoven, impregnated textile, fur, etc.) according to the method of further use of the laminated sheet material. The advantage of the finished materials is the softness and high vapor permeability caused by the central carrier porous layer, since this porous layer normally achieves a low bulk density (100-300 kg / m @ 2), which, with high porosity and fine polymer porosity, have a decisive influence on wearing comfort.

The following examples are intended to illustrate the invention in more detail, but do not limit the invention in any way.

Example,

A whipped mixture containing (in parts by weight) the following ingredients was prepared:

aqueous dispersions of aliphatic polyurethane (50 * 6 dry matter) 100 acrylate thickener 2 ammonium salt of stearic acid (surfactant)

By applying and drying the mixture, a lightweight, 0.15 mm thick middle layer of 300 kg / m @ 2 was prepared. This layer was bonded to a thermo-plastic polyurethane coating (20 g / m 2) with a polyamide coating (2 g / m 2). Further, a nonwoven backing layer impregnated with butadiene acrylonitrile rubber was attached using an acrylate dispersion (0.07 mm).

The manufactured material with a thickness of 1.2 mm has a water vapor permeability of at least 1.5 mg -2 -1 cm h and is suitable for footwear.

Example 2

A 0.15 mm layer of foam having a density of 400 kg / np produced by whipping the following mixture (in parts by weight) was applied to the dried overcoat as in Example 1:

aqueous polyurethane dispersion (40% dry matter) 100 precipitated limestone 20 polyacrylate thickener 1, 5 phenol-formaldehyde condensate 5 pigment premix 2 ammonium stearic acid salt 4

After drying at 100-170 [deg.] C., a 0.1 mm acrylate laminate layer of the composition of Example 1 is applied to this layer.

A laminate, preferably cotton, may be applied to the lamination layer, but may also be a cotton / polyester, viscose or polyamide combination having a basis weight of 100 to 200 g / m ² . When using a lighter fabric, the lamination layer can be homogeneous, for a fabric with a basis weight of about 200 g / m ² , lamination layer whisked to a density of 400 to 600 g / m ² is preferable. reverse of the product.

The material obtained is characterized by softness, drapeability and is particularly suitable for clothing applications.

Example 3

A 0.2 mm thick layer of foam having a density of 600 kg / m < 2 > produced by whipping the following mixture (in parts by weight) was applied to the dried cover layer on the separator pad obtained as in Example 1:

aqueous polyurethane dispersion (50% dry matter) 60 aqueous rubber dispersion (40% dry matter) 40y float chalk 1θ thickener (carboxymethylcellulose 5%) 5 ammonium salt of stearic acid 1 pigment premix 2

After the layer was dried, the material was combined with faux fur:

a) laminate as in Example 2 with a cotton fabric of 100 g / m < 2 > The obtained material is then laminated with faux fur using a polyurethane foam by flame,

b) direct lamination of the fur into a foam lamination layer (layer thickness 0.25 mm) prepared according to Example I.

The produced material of type a) additionally contains a textile interlayer which has the advantage, however, that it perfectly prevents the impingement of unevenness from the back of the faux fur into the face of the product.

The material of type b) is considerably simpler to manufacture, and at the optimum thickness and quality of the porous layer it also has a very good surface.

Both materials are suitable for clothing and footwear applications.

Example

A 0.1 mm layer of a 25% solution of thermoplastic polyurethane was added to the separating substrate with a desen with the addition of 2% by weight pigment paste. After drying at 70 to 120 ° C, a 0.25 mm thick layer of foam of 500 kg / m 2 was obtained on this layer obtained by foaming the following mixture on a high shear mixer (in high-density parts) an aqueous dispersion of aliphatic polyurethane (100% modulus 1). , 6 MPa, dry matter 40%) 70 aqueous dispersion based on acrylate (dry matter 50%) 30 finely ground kaolin 25 polyacrylate thickener 1 melamine formaldehyde condensate

NH 4 OH concentrated to 8 to 9 3 Pigment masterbatch 2 surfactant 2

After drying at 100 DEG-170 DEG C., a 0.15 mm laminating layer of foam having a density of 500 kg / m @ 2 obtained by whipping the mixture (in parts by weight) was applied to this layer: an aqueous dispersion of acrylate-based copolymer (dry matter 60%). aqueous polyurethane dispersion (dry matter 40%) 50 polyacrylate thickener

NH 4 OH concentrated pH 8 to 9 2

A non-woven fibrous layer impregnated with microporous polyurethane was applied to the lamination deposit. After the lamination layer is dried at 100 to 180 ° C, the material is cooled and separated from the temporary support.

The obtained laminate has a thickness of 1 mm, a water vapor permeability of at least 21 mg cm < -1 > and is suitable for shoe applications.

Claims (3)

SUBJECT OF THE INVENTION CLAIMS 1. A soft, breathable laminate composed of a central porous polymeric layer bonded on one side to a polymeric backing layer and a second polymeric backing layer optionally impregnated with a polymeric porous polymeric layer, wherein the intermediate porous polymeric layer is obtainable by drying and bonding 2. The composition of claim 1, wherein the aqueous dispersion is a polymer dispersion, characterized in that a polyurethane, polyacrylate or rubber dispersion or a mixture thereof having a dry matter content of 30 to 65% by weight is used as the aqueous dispersion. and by adding a surfactant in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the dispersion whose viscosity is adjusted to 0.5 to 25 PaS by the addition of a thickener. 2. The laminate of claim 1, wherein the whipped composition for the intermediate porous layer comprises 0.01 to 30 parts by weight of filler per 100 parts by weight of polymer dispersion. 3. A layered material as claimed in claim 1, wherein the whipped mixture for the intermediate porous layer comprises 0.01 to 20 parts by weight of a crosslinking agent per 100 parts by weight of polymer dispersion.