DE2725374A1 - PROCESS FOR THE PRODUCTION OF A POLYVINYL CHLORIDE SOFT FOAM WITH A RELIEF-LIKE SURFACE STRUCTURE BY THE PAINTING PROCESS - Google Patents

Description

272537Λ

CHEMISCHE WERKE HÜLS AG - RSP PATENTS -

h'JJO Mari, 6/3/77 4 /

Our sign; O.Z. 2977

Process for the production of a polyvinyl chloride flexible foam with a smooth surface structure using the coating process

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Flexible polyvinyl chloride foams with a relief-like surface structure, which are produced by the coating process are mainly used as floor and wall coverings. They are generally made up of three layers: a dimensionally stable carrier layer, ζ. B. asbestos cardboard, glass fiber fleece inter alia, a middle layer made of foamed soft polyvinylchloride and a transparent wear layer made of unglazed Soft polyvinyl chloride.

The special decorative effect of these flexible foams is primarily offset by the relief-like surface texture. In addition, these flexible foams have heat- and sound-insulating properties, are water-resistant and, when used as floor coverings, show a considerable amount of walking.

The relief-like surface structure, the so-called embossing, is achieved according to the prior art by several different modes of operation.

In "chemical embossing" (see US Pat. No. 2 <? 18,702, 3,293,092 +, 3,293,108, 3,399,107), the foamable middle layer made of polyvinyl chloride paste is applied to a carrier layer and heated to a comparatively low level Temperature of 120 to 14o C converted into a solid, printable state (pre-gelled). At this low temperature, foaming of the middle layer is avoided. A pattern is printed onto the pre-gelled layer of foamable paste using inhibitor paint. The inhibitor ink reacts with the blowing agent or the kicker of the foamable paste and therefore prevents foaming at the printed areas in the later processing stages. Finally, a layer of non-foamable, unpigmented polyvinyl chloride paste is applied to the pre-gelled layer, which has been printed with inhibitor ink, or a transparent polyvinyl chloride calender film is laminated on. The composite covering thus obtained is then placed in a gelling channel

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high temperature (j> 200 C) gelled and foamed. the printed areas remain unfoamed and, as indentations, create the relief-like structure.

Variations of "chemical embossing" are processes in which instead of the inhibitor color, one containing a kicker Color is printed on the pre-gelled foamable paste layer (GB-PS 1 1 ^ 7 983). In these cases the foamable paste does not contain a kicker. When such a composite covering is heated with gelation and foaming the printed areas will foam up much more and thus produce the desired relief-like structure.

It can be seen that the process of so-called chemical embossing through the separately carried out step of printing Require considerable effort and it seems desirable to find a method which such an additional Step avoids.

The relief-like surface structure can also be obtained by actual mechanical embossing (see. "Finishing of plastic surfaces, Klaus Stoeckhert (Editor), Carl Hanser Verlag, Munich 197 ² +, page 206-21 **). In such a method is applied to a Carrier a foamable middle layer as well as a compact (= non-foamable) polyvinyl chloride top layer applied, gelled and expanded and embossed immediately afterwards or in a separate operation.

Special embossing calenders must be used which, because of their low working speed, are usually not in the continuous Production process can be included, but require a separate work step. In addition, the Costs for an embossing roller are many times higher than the cost of the printing rollers for chemical embossing.

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This gives rise to the task of using a method for the production of polyvinyl chloride soft foam fabrics relief-like surface structure to find which of the Chemical or mechanical embossing stage is not required.

A method for producing a flexible polyvinyl chloride foam has now been established with a relief-like surface structure after the brushing process by applying a chemical Foamable polyvinyl chloride paste containing blowing agent on a carrier material, pre-gelling at 100 to 170 ° C., if necessary Applying a non-foamable polyvinyl chloride paste as a cover layer to the foamable layer and, if necessary Pre-gelation at 100 to 170 ° C, gelation and foaming found at high temperature, which is characterized in that the carrier material prior to gelling and foaming underlaid with a metal foil provided with recesses and the composite covering in the gelation channel predominantly or exclusively is heated from above.

The temperature of the hot air of the gelation channel is preferably 200 to 320 ° C.

In a further preferred embodiment of the method is the dwell time of the composite covering in the gelling channel 30 up to 180 see.

When practicing this procedure, all parts of the schiiumbaren layer, which are located above the metal, not foamed, while those above the recesses in the metal foil get parts of the foamable layer to foam.

As a metal foil provided with recesses, the simplest Use a large-mesh filter belt in the case. A herringbone pattern is obtained.

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The recesses should have a size of at least 2 mm. In order to get to special patterns, it is sufficient to have one accordingly to let the punched metal foil run along on the sieve belt of the gelation channel under the composite covering.

As a material for the metal foil provided with recesses, with which the composite covering is underlaid according to the invention, metals such as copper, nickel, iron, aluminum, zinc or metal alloys such as brass, Bronze, aluminum bronze, and also plated sheets made of two or more metals, as well as galvanized sheets used. The metal should have a thermal conductivity of at least 0.10 own. The thickness of the slide

cm. see. Degree

should be 0.3 to 5 mm.

The hot air of the gelation channel should be directed predominantly or exclusively from the upper nozzles onto the composite covering, ie at least 5/6 of the hot air volume should reach the composite covering from the upper nozzles. An increased discharge of hot air from the lower nozzles worsens the result.

Polyvinyl chloride pastes which are used for the process according to the invention can be used, are made in the usual manner from paste-compatible polyvinyl chloride powders, such as emulsion polymers and microsuspension polymers and the corresponding proportions made from common plasticizers. examples for Plasticizers are: dioctyl phthalate, dinonyl phthalate, didecyl phthalate, Butyl decyl phthalate, dicapryl phthalate, butyl benzyl phthalate, Dioctyl adipic acid ester, dioctyl sebacic acid ester, tricresyl phosphate, trioctyl phosphate and cresyl diphenyl phosphate. The pastes can be produced by the customary paste-mixing process (see rubber-asbestos-plastics, vol. 23/1970, page 938). The ratio of polyvinyl chloride powder to plasticizer should be 45:55 to 70:30.

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The pre-gelling and the gelling and foaming of the composite flooring can be carried out in a gelling channel of the usual type (hot air drum oven), as described in Paul Schmidt, coating with plastics, Carl Hanser Verlag Munich I967, Pages 77 to 80 is described.

The chemically decomposable blowing agent for the layer capable of being exposed can be, for example: azodicarbonamide, benzoyl-1,3-disulfonylhydrazide, 5-morpholyl-1,2,3> ^ - thiatriazole, toluenesulfonylhydrazide, N, N'-dinitrosopentamethylenetetramine, diphenylsulfonene -3 »3 ¹ -disulfohydrazide, azo-bis-isobutyronitrile or mixtures thereof. In general, amounts of 0.5 to 8 percent by weight, preferably 1 to 3 percent by weight, based on PVC, are used.

As carrier materials firmly bonded to the foam layer, asbestos cardboard, glass fiber fleece, PVC calender film, jute fabric; Nonwovens, woven and knitted fabrics made from natural or synthetic fibers; Felt, paper, and thin card stock as well PVC-repellent paper, which is removed at the end, can also be used. If the carrier material is too thick, the The definition of the embossing is reduced. The layer thickness of the The carrier material should therefore preferably not be more than 1.5 mm.

The following examples are intended to explain the process:

example 1

A foam paste of the following composition with 600 g / m 2 was applied to a carrier material (wallpaper paper weighing 135 g / m 2) Painted order:

100 parts of emulsion polyvinyl chloride, K-Vert 70

27 parts of dioctyl phthalate

28 parts of benzyl butyl phthalate 1 part of zinc oxide

h parts azodicarbonamide masterbatc '' in DOP (1: 1)

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This coating was at 120 C and a residence time of Pre-gelled in the gelling channel for 1.3 min. A clear wear layer was then applied with 300 g / m 2 according to the following composition applied and also pre-gelled at 120 C / 1.3 min:

100 parts microsuspension polyvinyl chloride,

K-Vert 70

49 parts of dioctyl phthalate, 4.7 parts of epoxy plasticizer 2.3 parts of tin stabilizer

This pre-gelled but still unfoamed composite covering was placed on a foil made of copper metal which contained circular holes of 5 mm diameter at a distance of approx. K mm. After passing through the 270 hot gelation channel, in which the hot air was preferably blown (approx. 5/6) from above onto the composite covering, with a dwell time of 60 seconds, a relief-like embossed foam covering with circular elevations of 5 mm diameter was obtained.

Example 2

The composite covering produced according to Example 1 was underlaid with a metal foil (galvanized iron), which contained square openings J mm on a side at a distance of 7 mm, and through the gelation channel heated to 320 ° C during a

^^ it sent by 30 see. The result was a relief-like appearance Embossed foam covering with square elevations with a side length of 7 mm. The heating was done mainly by overhead air (5/6), the contours of the relief-like elevations were sharply defined.

Example 3

A foam paste of the following composition was applied at 800 g / m 2 to a carrier material (cotton fabric weighing 270 g / m 2) and pregelled at 120 ° C. for 1.3 min:

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100 parts of emulsion polyvinyl chloride 32 parts of dioctyl phthalate

15 parts of butylbenzyl phthalate 6 parts of azodicarbonaraid masterbatch in DOP (i: 1) 1.5 parts cadmium-zinc kicker / stabilizer

This pre-gelled, but still unfoamed coating was underlaid with the copper metal foil mentioned in Example 1 with circular holes 5 mm in diameter and passed through the 300 ° hot gelling channel with a dwell time of "} 6 seconds. A foamed coating with circular holes resulted Elevations with a ^{diameter of 5 mm} , the contours of which were slightly less sharp than in the case of the composite covering produced in Example 1 (with wear layer), since this is where the weight is applied

the foam layer was larger at 800 g / m 2.

Comparative example

The procedure was as in Example 2, but in the gelation channel Hot air supplied in equal parts from above and below. The relief-like surface structure was not very sharp,

As the examples show, it is possible according to the invention, under Saving the measure of embossing to produce polyvinyl chloride foams with a relief-like surface structure.

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Claims (3)

■) 725374 O.Z. 297 03 Ob.77 Claims Process for the production of a polyvinyl chloride flexible foam with a relief-like surface structure after the brushing process by applying a chemical Foamable polyvinyl chloride paste containing blowing agent on a carrier material, pre-gelling at 100 to 170 C, if necessary, application of a non-foamable polyvinyl chloride paste as a top layer on the foamable layer and optionally pregelatinizing at 100 to 170 ° C., gelling out and foaming at high temperature, characterized in that the carrier material prior to gelation and foaming underlaid with a metal foil provided with recesses and the composite coating in the gelation channel predominantly or is only heated from above. 2. The method according to claim 1, characterized in that the temperature of the hot air of the gelation channel is 200 to 320 ° C amounts to. 3. The method according to claim 1 and 2, characterized in that the dwell time of the composite coating in the gelling channel 30 180 seconds. 809850/0288 ORIGINAL INSPECTED