DE3543266A1 - Process for producing a crosslinked PVC wear layer - Google Patents

Abstract

A PVC wear layer is produced by applying a coatable preparation containing PVC, a crosslinking agent, a photosensitiser and, if appropriate, further conventional additives to a substrate and gelling it by means of heat. The gelled wear layer is then crosslinked by UV radiation. The wear layer obtained is heat resistant, as is especially clearly illustrated when cigarettes are stubbed out on coverings.

Description

Process for the production of a cross-linked PVC wear layer

The invention relates to the production of a cross-linked PVC wear layer according to the preamble of claim 1.

Polyvinyl chloride wear layers have a wide range of uses for Wall and floor coverings found. They are mechanically stable, hardly inflammable and have good chemical resistance. However, problems arise with the heat resistance of these thermoplastic layers. In particular, leave behind burning cigarettes unwanted permanent damage. To the heat resistance To improve the layers were made by electron beams and radioactive rays or free radicals linked. The first two methods are costly and require extensive security measures; the third method yields unsatisfactory quality Products.

In order to avoid these disadvantages, it was proposed in FR-A 1 79 19843, one of a mixture of polyvinyl chloride, a reactive plasticizer (crosslinking agent), a sheet formed by calendering a photosensitizer and a stabilizer or to crosslink the plate by means of UV radiation. To get through the gelling of the reactive To avoid plasticizer caused by the calendering heat inhomogeneity, is a polymerization inhibitor was added to the PVC mixture. The calendered films or plates are then before or after irradiation with UV light with a plate or other hard substrates glued or welded under pressure. This procedure is therefore not suitable for the production of a wear layer for a soft one and / or underlay provided with a relief, as is often used for floor coverings will, since the latter give way when pressed together, which affects the quality of the connection impaired or the relief damaged.

The object of the present invention was therefore to provide a method of To create the type mentioned at the beginning, the networked, in particular heat-resistant PVC wear layers for soft and sensitive substrates.

This object was achieved according to the invention by the features of the characterizing Part of claim 1 solved.

By applying a PVC preparation in a spreadable state the underlay material is mechanically stressed to such an extent on the underlay, that e.g. already existing relief structures are not impaired. Simultaneously there is a continuous, gapless contact between the base and the PVC preparation brought about, which together with the subsequent gelling a flawless connection of the touching layers. But the spreadability also allows To develop the relief structure of the base only after the PVC preparation has been applied, because the plastic PVC preparation does not hinder the deformation of the base.

The inventive combination of the method steps one that is crosslinked by means of UV rays and that is heat-resistant, especially when it comes to burning Cigarettes have a resistant, qualitatively flawless PVC wear layer, which remains soft, pliable and malleable until it is crosslinked and during manufacture problem-free can be handled.

Surprisingly, it was found that by the, during gelling applied heat, which in calendering already at low temperatures without Polymerization inhibitor observed cloudiness and unevenness of the PVC wear layer does not occur, so that a qualitatively perfect PVC wear layer prevents the gelling oven which then or at a later point in time of the networking means Is subjected to UV radiation.

The use of the spreadable PVC preparation, i.

the shaping without heating allows greater freedom of formulation than is possible with calendered sheets, e.g. the use of PVC with higher molecular weight and less crosslinking agent, as well as manufacturing a softer product with up to 120% by weight of a commercially available plasticizer. In addition, there is a gelled, i.e. manipulatable, However, there is still a thermoplastic wear layer in front of what the advantageous implementation of further work steps between gelling and crosslinking allowed. For example the gelled PVC wear layer can be printed and / or sent for further processing will.

Both semifinished products are used as the basis for the method according to the invention as well as removable intermediate supports in question. In the first case, the semi-finished product can contain a foamable layer, the foaming of this layer and the Gelling of the PVC wear layer can take place in the same heat treatment. That with the semi-finished product provided with the gelled PVC wear layer or the intermediate carrier afterwards or after carrying out further crosslinking treatment steps fed.

If desired, the intermediate carrier can already be used before networking can be peeled off the gelled PVC wear layer.

Spreadable PVC preparations generally contain, with the exception of PVC, the known photosensitizers and the crosslinking agents, which are preferred are polyfunctional monomers and oligomers, plasticizers, thinners, heat stabilizers and catalysts or those counteracting damage caused by UV radiation UV stabilizers.

For the process according to the invention, types of PVC that are produced by emulsion, Suspension or microsuspension polymerization were obtained, or mixtures thereof be used. By choosing a higher molecular weight polyvinyl chloride the degree of crosslinking and thus the heat resistance of the end product can be improved will.

Commercially available products can be used as plasticizers, for example Phthalate-based are used, as they are usually used when mixing PVC plastisols Find use. As the nature of this plasticizer affects the degree of crosslinking of the end product also influenced, its choice can be optimized through preliminary tests. The PVC preparations can contain up to 120% by weight, preferably up to 80% by weight, plasticizers, without the heat resistance of the wear layer being impaired.

The thinners used are known and are already used for PVC plastisols used. There are also reactive thinners, e.g. monomers, which on the one hand can participate in the crosslinking reaction and on the other hand the rheological processing properties control the mix, As heat stabilizers, those based on of organic barium and zinc salts, e.g. Ba-Zn decanoates, are used, such as they are already used for PVC plastisols.

Particularly suitable catalysts for the crosslinking reaction are Substances containing amine groups.

Preferred crosslinking agents are those containing reactive acrylic groups Monomers and oligomers, the latter preferably with a molecular weight of 400 up to 900. The use of higher molecular weight oligomers is possible, but requires special precautions when mixing. For the achievement a good heat resistance are preferably at least trifunctional compounds used. The addition of monofunctional compounds improves elasticity the PVC wear layer. The strongest network and therefore the best heat resistance is achieved with pentafunctional acrylates. The bifunctional acrylates have in addition to their function as participants in the crosslinking reaction, they also act as reactive thinners.

To start the crosslinking reaction under the action of UV rays Radical formers such as benzophenone, acetophenone and the like are used as photoinitiators used.

Polymerization inhibitors, as they are according to the known method for Prevention of gelation of the polyfunctional monomers prior to UV irradiation are essential, are not required according to the invention.

To the PVC etch layer obtained against the destabilizing effect Can protect from UV rays UV stabilizers in the PVC preparation can be used.

The invention is further illustrated by the following examples: Examples 1 to 7 PVC preparations were produced with the following compositions: example No. 1 2 3 4 5 6 7 High molecular weight polyvinyl chloride 100 100 100 100 100 100 100 dipentaerythritol monohydroxy pentaacrylate 9 9 9 9 9 - - (PENTA) trimethylopropane triacrylate (TMPTA) 9 9 9 9 9 - Benzophenoderivat as a sensitizer 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Ba-Zn heat stabilizer 3 3 3 3 3 3 3 Dioctyl phthalate 60 - - - - 60 60 Diisononyl phthalate - 60 - - - - -Benzyl butyl phthalate - - 60 - - - -Dionyl adipate - - - 60 - - -phosphoric acid ester - - - - 60 - -Trimethylalpropane -trimethylacrylate - - - - - 35 -acrylic oligomer (MW = 900) - - - - - - 25 Ethoxylated trimethylpropene trimethyl acrylate These Preparations were made on siliconized release paper with a doctor blade or an aluminum plate applied, gelled in a hot air oven and using Cross-linked UV radiation.

The individual samples show good resistance to heat, though they come into contact with burning tobacco products.

Examples 8 to 11 In these examples the influence of the used Starting materials, the degree of crosslinking and thus the heat resistance shown.

Determination of the degree of crosslinking To determine the degree of crosslinking is the sample to be tested in a Soxhlet apparatus with tetrahydrofuran (THF) during extracted for at least 48 hours. The residue that is not extracted is a measure of the degree of crosslinking, which is calculated as follows: A) PVC + monomers maximum not extractable portion that can take part in the crosslinking B) plasticizer portion, which is extracted and thus does not take part in the crosslinking C) residue after the extraction C degree of crosslinking y = A 100% sensitizer and heat stabilizer are distributed half between A and B, Example 8 Influence of the polyfunctional monomers to the degree of crosslinking a b PVC 100 100 benzyl butyl phthalate (BBP) 60 60 heat stabilizer 4 4 photoinitiator 4 4 trimethylolpropane trimethylacrilate (TMPTMA) 50 dipentaerythritol monohydroxypentaacrylate - 50 degree of crosslinking 76.92% 99.27% The use of a pentafunctional monomer (b) resulted in an end product which survived the extraction by tetrahydrofuran (THF) practically unchanged.

Example 9 Influence of the plasticizer on the degree of crosslinking a b PVC 100 100 TMPTMA 60 60 heat stabilizer 4 4 photoinitiator 4 4 diisononyl phthalate (DINP) 60 60 Dioctyl phthalate (DOP) - 60 Degree of crosslinking 85% 89.4% The end products with DOP had a higher proportion of non-extractable material.

Example 10 Influence of the plasticizer content on the degree of crosslinking a b c d e f polyvinyl chloride 100 100 100 100 100 100 PENTA 6 6 6 6 6 6 TMPTA 15 15 15 15 15 15 Ba-Zn heat stabilizer 4 4 4 4 4 4 W sensitizer 1 1 1 1 1 1 Dinonyl adipate 50 60 70 80 100 120 Degree of crosslinking (%) 66.9 66.1 66.2 66.3 65 60.2 Increasing the plasticizer content from 60 to approx. 100 reduced the degree of crosslinking only insignificantly. Only at a higher plasticizer concentration is there a clear decrease ascertain.

Example 11 Influence of the molecular weight of PVC on the degree of crosslinking a b PVC (K value: 63) 100 PVC (K value: 80) - 100 TMPTMA 50 heat stabilizer 4 photoinitiator 2 2 BBP 60 60 degree of crosslinking 47.5% 65.8% PVC with a higher molecular weight resulted an end product with a much higher proportion of cross-linked material, Example 12 The following preparation was produced PVC (K value = 100) 75 PVC (K value = 80) 125 Pentaacrylate 20 Triacrylate 20 DOP 120 Heat stabilizer 6 Photoinitiator 2 W stabilizer 0.2 It could be easily applied to a surface using the brush technique. Their storage stability was good.

Example 13 The preparation according to Example 12 was according to a for the production of plastisols usual process mixed, filtered and deaerated and in a system which is shown schematically in FIG. 1 and is known per se processed.

In this system 1, a supply roll 2 becomes a semi-finished product 3 peeled off and carried out under a doctor blade 4, with which the plastisol is applied according to Example 12. In a subsequent hot air oven 5 is by the action of heat, a layer of the semi-finished product containing a blowing agent 3 foamed and the plastisol gelled, with its thermoplastic properties fully preserved. The latter are for the subsequent processing steps essential. The semi-finished product passes through the hot air oven 5 with a temperature profile from 190-205-210-190 ° C at a speed of 15 m / min., which is a dwell time of about 2 minutes 30 seconds.

Then the semi-finished product, with the foamed layer and the gelled one Wear layer, swept in the station 6 and with a coating device 7 is a Back coating applied. The latter is gelled in an oven 8. Afterward the web emerging from the oven 8 is used to cross-link the PVC wear layer High pressure mercury lamps 9 with 80 and 120 W / cm power. These UV lamps have a selective emission spectrum from 250 to 420 nm. The obtained Web-shaped product 11 is then either fed to a supply roll 12 and wound up or packed directly to the finished product in rolls of customary lengths.

This product 11, which can be used as a floor covering, has the section shown in FIG. 2 structure shown schematically.

The back coating 13, which has a cellular structure, was applied with the coating device 7 and is to lie on a base, e.g. soil, determined. The back coating is followed up by a carrier 14, which was already included in the semi-finished product 3 and the dimensional stability of the product 11 guaranteed.

On the carrier 14 is a foamed layer 15 with a relief structure and a print pattern 16 is arranged. This layer 15 was in the oven 8 at the same time foamed with the gelling of the transparent wear layer 17, the relief structure as well was achieved.

The production of the semi-finished product 3 or, the foaming to a Layer with a relief surface is described in detail in CH-PS 458 712. The PVC wear layer 17 of the product obtained is homogeneous, transparent and shows no permanent changes in contact with burning tobacco products or when squeezing out lit cigarettes on their surface. She is up to about 3500C heat resistant. On the other hand, the usual wear layers are already much deeper Temperatures irreversible damage to the wear layer and, as a result, possibly the foamed layer underneath can be observed.

The heat resistance was measured with a stamp under a pressure of 1 bar (0.1 N / mm2) tested with increasing temperature. A common PVC wear layer 0.5 mm thick was already completely penetrated by 1300. However, was in the case of a PVC wear layer according to Example 12, also 0.5 mm thick at 3400 only a penetration depth of approx. 67% was observed, i.e. that under the wear layer Shift was not violated.

On the surface of the gelled wear layer can, preferably directly before cross-linking, a very thin layer of varnish made of a material that can also be UV cross-linked applied and cross-linked together with the wear layer. The use of such Plasticizer-free lacquer layers based on acylate as dirt-repellent layers is already known from US Pat. No. 4,100,318. In the present case, they also allow the easier removal of scorch marks from cigarettes.

While in US-PS 4 100 318 the lacquer layer with it underlying Layer made of normal soft PVC is only mechanically connected, there is the advantage the according to the invention Execution in that a networking transversely takes place through the layer and thus an optimal anchoring of the lacquer layer is guaranteed.

Except for the floor covering described in detail above wall coverings, coverings, self-supporting wear layers and so-called Homogeneous coverings are produced. In the latter case, the gelled PVC wear layer is used mounted on calender coverings by an intermediate carrier and then crosslinked.

To the process through the use of smaller amounts of acrylate crosslinking agent To make it as economical as possible, the wear layer can be added in two steps the base can be applied, the PVC preparation applied in the first step does not contain any crosslinking agent. This first wear layer part can then be gelled are applied before the second wear layer part containing the crosslinking agent will. Furthermore, according to the invention, the wear layer can be crosslinked in two steps will.

The first partial crosslinking step is as close as possible after the gelling oven and the second step at the end, as with one-step crosslinking, executed. After the partial crosslinking, the wear layer still remains soft and flexible, i.e. the properties which are favorable for handling are retained, however it has a higher lubricity and requires less care with the Handling.

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Claims (17)

Claims 1. A method for producing a by UV radiation cross-linked, in particular heat-resistant polyvinyl chloride wear layer made of a Containing polyvinyl chloride, a crosslinking agent and a photosensitizer Preparation, characterized in that the preparation is spreadable Condition applies to a base, in a first step by the action of heat gelled and crosslinked in a further step by UV radiation. 2. The method according to claim 1, characterized in that the spreadable preparation in the form of a plastisol applied to the base. 3. The method according to claim 1 or 2, characterized in that the spreadable preparation is applied to a foamable layer, in the first Step by heat treatment, the foamable layer is foamed and the preparation gels and in a further step the polyvinyl chloride wear layer is exposed to UV radiation networked. 4. The method according to claim 3, characterized in that according to the gelling of the polyvinyl chloride wear layer on the side facing away from the latter the resulting sheet applies a further layer, this gels and then the polyvinyl chloride wear layer is crosslinked using UV rays, 5. Procedure according to claim 1 or 2, characterized in that the spreadable preparation applies to a peelable backing. 6. The method according to claim 5, characterized in that the Polyvinyl chloride layer peeled off from the support after gelling, onto a sheet-like structure laminated on and then crosslinked by means of UV radiation. 7. The method according to claim 6, characterized in that as Sheet-like structure used a flexible semi-finished product. 8. The method according to claim 6, characterized in that as Sheet-like composite panels used. 9. The method according to claim 6, characterized in that one thermoplastic fabric used. 10. The method according to any one of the preceding claims, characterized in, that a polyfunctional monomer and / or oligomer and optionally a monofunctional monomer is used. 11. The method according to any one of the preceding claims, characterized in, that a 3 to 5 functional acrylate is used as the crosslinking agent. 12. The method according to any one of the preceding claims, characterized in, that no polymerization inhibitor is used in the preparation. 13. The method according to any one of the preceding claims, characterized in that that a preparation containing up to 100 wt .-%, preferably 80 wt .-%, one commercial plasticizer used, 14. Method according to one of the preceding Claims, characterized in that one is on the gelled polyvinyl chloride wear layer one essentially from the Crosslinking agents, preferably from Acrylate applies the existing lacquer layer and the latter together with the wear layer cross-linked by means of UV radiation. 15. The method according to any one of the preceding claims, characterized in, that one crosslinking in several, preferably two, steps by means of UV radiation. 16. Wear layer, produced by the method according to one of the claims 1 to 15. 17. Floor or wall covering with a wear layer according to claim 16.