EP0091622A2 - Process and apparatus for the manufacture of floor webs - Google Patents

Abstract

A carpet tile placed on the underside of a textile floor covering, e.g. a needle felt or a tufted fabric, a primer and a subsequent heavy layer is prepared so that an activated, optionally filled with filler isocyanate-polyol mixture is used as a primer, which does not react to polyurethane at temperatures near room temperature, and as Heavy layer a thermoplastic is used, wherein the primer and the heavy layer are successively applied to the carpet web on the same lower roller and wherein the primer roller and the activated isocyanate-polyol mixture is kept at a temperature between the dew point of the water and a temperature at which there is still no reaction of the isocyanate and the polyol and the heavy layer and the heavy-layer roller doctor blade are kept at a temperature at which the heavy layer has liquid properties and the isocyanate-polyol mixture reacts with one another to form polyurethane.

Description

The present invention relates to a method and an apparatus for the production of carpet tiles, whereby the underside of a textile floor covering, e.g. a needle felt or a tufted product, first a primer and then a heavy layer is applied and the carpet web thus produced is punched into carpet tiles.

For the production of textile floor coverings, for example carpet tiles, for example, a tufted fabric or needle felted fabric is generally provided on its underside with a back coating which consists of a heavy layer, for example of bitumen. However, it has been shown that the textile fibers can easily detach from such tufted goods or needle felted goods, especially if the floor covering is subjected to external stress. For this reason, it has long been the practice to apply a primer to carpet tiles whose durability is subject to greater demands before coating them with the heavy layer on the underside of the tufted goods or needle felted goods, which penetrates into the filaments of the knobs and sticks or sticks the textile fibers connects to the base fabric / fleece. Although this requires an additional processing step, the primer this way of working prevailed, because until now this was the only way to produce a durable carpet tile that can withstand even greater stress.

Filled polyurethane was also used as the heavy layer. A primer is not required. However, the lying properties and dimensional stability of such carpet tiles are unsatisfactory, and polyurethane is also expensive. For this reason, hotmelt compositions based on atactic polypropylene or bitumen are used almost without exception as the heavy layer for carpet tiles, whereby the need for a separate primer is accepted.

The object of the present invention is to provide a method and a device for producing a carpet tile which is considerably simplified compared to previous production with primer and subsequent application of the hotmelt heavy layer and which offers the possibility of producing an inexpensive carpet sheet for tiles in one operation .

This object is achieved in that an activated isocyanate-polyol mixture, which may be filled with fillers and does not react to polyurethane at temperatures near room temperature, is used as the primer, and a thermoplastic is used as the heavy layer, the primer and the heavy layer being in succession are applied to the carpet web on the same lower roller and the primer roller and the activated isocyanate-polyol mixture are kept at a temperature between the dew point of the water and a temperature at which there is still no reaction of the isocyanate and the polyol and the Heavy class and the heavy class Roller doctor blades are kept at a temperature at which the heavy layer has liquid properties and the activated isocyanate-polyol mixture reacts with one another to form polyurethane.

The solutions according to the invention with regard to the device result from the characteristics of the device claims.

When using a pre-coat mixture of isocyanates, polyols and activators that do not react with each other at temperatures close to room temperature, the liquid isocyanate-polyol mixture first penetrates into the underside of the carpet web, so that the ends of the textile fibers are well soaked in the pre-coat mixture . This will be. favors that the flowability of the isocyanate-polyol mixture is fully maintained because the reaction does not take place, as a result of which the primer penetrates well into the fibers or knobs under the pressure of the primer roller.

The heavy layer can then be applied to the same lower roller immediately after the application of the primer. The heavy layer consists of a thermoplastic that is applied to the underside of the carpet at elevated temperatures. The temperature of the thermoplastic to be applied must be set so that, on the one hand, the required fluidity or viscosity is guaranteed, for example, to be able to be applied to the underside of the carpet web with a roller doctor blade, on the other hand, the temperature must be selected so that it is at room temperature not yet reactive isocyanate-polyol mixture under the influence of the elevated temperature of the heavy layer now reacts to form polyurethane. This fin det simultaneously with the application of the heavy layer, the curing of the primer takes place without the need for separate operations or separate bottom rollers for the application of the primer and heavy layer.

The method according to the invention enables high speeds in the production of the carpet webs, with only minor investments being required. The fact that both layers, both the primer and the heavy layer, can be applied on a single lower roller means that no additional work step is required. By selecting appropriate compositions for the primer and the heavy layer, it is possible to set the flexural strength and the lying behavior of the carpet tile.

Compared to the use of polyurethanes as the coating material, the possibility of using cheaper thermoplastics as the heavy layer results in considerable cost savings with better lying properties.

The method according to the invention is suitable for the production of carpet tiles from all textile floor covering materials, such as e.g. Tufted goods, needle felted goods, woven goods or knitted goods.

The usual hot-spreadable thermoplastics are used for the heavy layer. These include atactic polypropylene, atactic polybutene, bitumen, ethylene-vinyl acetate polymers (EVA), polyvinyl acetate and the like. Natural rubber, polyethylene, polypropylene, polybutene, polyisobutylene, propylene rubber, ethylene-propylene rubbers (EPDM, EPM) and mixtures of the substances mentioned can also be used as additives to these thermoplastics will. Atactic polypropylene, atactic polybutene, bitumen and mixtures of atactic polypropylene and atactic polybutene, atactic polypropylene and polyethylene and of atactic polypropylene with resins are preferably used. Suitable resins are natural and / or synthetic resins, for example hydrocarbon resins. Aliphatic hydrocarbon resins or natural resins such as rosin or root resin are preferably used.

The heavy layer can be filled with the usual fillers and additives, e.g. Fillers with a density above 2, such as barium sulfate, calcium carbonate, silicon dioxide, slate powder, limestone powder, quartz sand, etc. Plasticizers, antioxidants, dyes, pigments, etc. can also be used as additives.

The heavy layer is applied at temperatures from 80 to 220 ° C., preferably 120 to 200 ° C. and particularly preferably at 150 to 180 ° C.

When using mixtures of atactic polypropylene and atactic polybutene, the application temperatures are about 150 to 180 ° C, when using high molecular weight atactic polypropylenes the temperatures can be between 120 and 220 ° C. When hydrocarbon resins are added to atactic polypropylene, application temperatures are generally between about 120 and 180 ° C. When using bitumen, lower application temperatures are used, for example in the range from 80 to 180 ° C. When using fillers in atactic polypropylene, the application temperatures are at a high filler content, for example in the range from 50 to 80% by weight between about 160 and 200 ° C., and at a lower filler content below, for example 50% at about 140 to 160 ° C.

Suitable as a primer are all isocyanate-polyol mixtures that do not work at temperatures close to room temperature, i.e. do not react to any appreciable extent to form polyurethanes. These are, in particular, mixtures which cannot be converted to polyurethanes at temperatures between 0 and 100 ° C, preferably between 10 and 50 ° C and particularly preferably between 10 and 30 ° C, i.e. who do not yet react to any significant extent at these temperatures.

Such isocyanate-polyol mixtures contain, for example, di- or polyisocyanates, preferably aromatic diisocyanates, such as 4,4'-diphenylmethane diisocyanate (MDI) or tolylene diisocyanate (TDI) as the isocyanate component.

The following polyols are used as the polyol component: polyether and / or polyester diols or triols, or di- and / or trifunctional polyether and polyester polyols. In addition, monohydric or polyhydric alcohols, for example glycol, glycerin, etc., may be present.

Since the isocyanate-polyol mixture should not react with one another at temperatures close to room temperature, it is necessary to add special activators which only allow the mixture to react with one another at higher temperatures. Such activators are, for example, thermally activatable amine catalysts, which can consist of salts of amines with organic carboxylic acids or of complex-bound amines. At elevated temperatures, these substances disintegrate, releasing the amine that serves as an activator. Metal salts or organometallic compounds can also be used as thermally activatable activators. An example of such compounds is nickel (II) acetyl acetonate.

The activators can, for example, be mixed with the polyol component and added to the reaction mixture.

The mixture of isocyanate, polyol and activator can optionally contain the same fillers as the heavy layer.

The method according to the invention is explained in more detail below using an example.

Fig. 1 shows a device for performing the method according to the invention in a schematic representation.

A tufted carpet web 12, consisting of a polyamide material and a polypropylene carrier fabric, is transported from the unwinding device 10 via the deflection rollers 14 to the lower roller 22.

The reaction component 4,4'-diphenylmethane diisocyanate (isocyanate content as NCO> 30% by weight) (MDI) is in the storage container 16 and the corresponding second reaction component, consisting of, is in the storage container 18

In the mixing container 20, both reaction components isocyanate and polyol mixture are premixed in a ratio of 1: 7.8 and applied to the carpet web via a primer roller 24. The order quantity is predosed with the help of the doctor blade 26. The temperatures of the polyurethane reaction components as well as of the reaction mixture, the pre-wipe roll and the lower roll be + 15 ⁰ C. The coating weight of the primer is 35 ₀ g / _m ^2.

The precoated carpet web is fed to the heavy-layer roller doctor 30 on the lower roller 22, which rotates in the running direction. In the reservoir 28 there is a hotmelt heavy coating composition consisting of

The temperature of this mass is 170 ° C. With the aid of the heavy-duty roller blade 30, which is also heated to 180 ° C., this mass is applied from the storage container to the pre-coated carpet web, the application weight is 2,000 g / _m ² .

The reaction of the activated isocyanate-polyol primer mixture to polyurethane is initiated by the action of the elevated temperature of the coating of the carpet web with the hot heavy coating composition.

The carpet web is transported over a cooling section 32/34 and cooled to 20 ° C. With the cooling, the reaction of the isocyanate-polyol mixture is completed, so that the carpet web can be punched with the punch 36 into carpet tiles.

The carpet tiles produced in this way show a very good integration of the fiber filaments through the polyurethane primer and a very good dimensional stability.

Claims (8)

1. A process for the production of carpet tiles, a primer and then a heavy layer being applied to the underside of a textile floor covering, for example a needle felt or a tufted viare, and the carpet web produced in this way is punched into carpet tiles, characterized in that an activated, optionally filled with isocyanate-polyol mixture is used, which does not react to polyurethane at temperatures close to room temperature, and a thermoplastic is used as the heavy layer, the primer and the heavy layer being applied in succession to the carpet web on the same lower roller and
the primer roller and the activated isocyanate-polyol mixture being kept at a temperature between the dew point of the water and a temperature at which the isocyanate and the polyol are not yet reacting and
the heavy layer and the heavy layer roller doctor blade are kept at a temperature at which the heavy layer has liquid properties and the isocyanate-polyol mixture reacts with one another to form polyurethane. 2. The method according to claim 1, characterized in that a hot melt mixture is used as the thermoplastic. 3. The method according to claim 1 or 2, characterized in that atactic polypropylene is used for the heavy layer. 4. The method according to claim 1, 2 or 3, characterized in that the temperature of the roller for the heavy layer is kept at 80 to 220 ° C, preferably 120 to 200 ⁰ C and particularly preferably at 150 to 180 ° C. 5. The method according to claim 1, 2 or 3, characterized in that the temperature of the roller for the precoat is kept at 0 to 100 ° C, preferably at 0 to 30 ° C and particularly preferably at 10 to 15 ° C. 6. Device for performing the method according to claims 1 to 5, characterized by a lower roller (22), a pre-coating roller (24) and a heavy-duty roller doctor blade (30). 7. The device according to claim 6, characterized in that the primer roller (24) is equipped with devices for heating and cooling. 8. The device according to claim 6, characterized in that the heavy-duty roller doctor blade (30) is heatable.

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