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Udvikling af alternativt materiale til PVC i tęppefliser

English Summary

Carpet squares for floors in offices and institutions have up to now been produced by yarn pieces fixed in an adhesive made of plasticized PVC. Experiments with production of carpet squares using an adhesive based on water without PVC have shown promising results. Contrary to expectation it seems that carpet squares of woollen yarn containing the new adhesive can be produced using Westbond’s sandwich technique. Experiments with production of carpet squares made of synthetic yarns indicate that they must be produced according to a newly developed method.

Customers demand carpet squares without PVC

Carpet squares of high quality for floorings have up to now almost solely been produced with an adhesive based on PVC containing phthalate plasticizers. The adhesive has been improved through several years, and it results in carpet squares with eminent technical properties such as dimension stability, wearing qualities and non-inflammability (self-extinguishing).

Customers focus on environmental properties of carpet squares

However, still more buyers both in Denmark and e.g. Germany demand improved environmental properties of carpet squares. In this connection focus is on the harmful properties of PVC in case of fire and disposal by incineration (generation of hydrogen chloride). Furthermore, some of the phthalate plasticizers may have hazardous effects to health and may bioaccumulate in aquatic organisms.

So far the efforts of producing carpet squares of high quality without plasticized PVC have failed. Environmentally better alternatives to carpet squares containing PVC and phthalate plasticizers cannot be found on the market.

Objective

The objective of the project has been to develop carpet squares produced with an adhesive, not containing plasticized PVC, without resulting in any considerable reduction of quality, and then to develop a method for production of these new carpet squares.

Design of experimental equipment and experiments carried out

The development of carpet squares without PVC has primarily been effected by and in the firm Westbond in cooperation with Westbond’s German supplier of adhesives and the Danish Technological Institute. The development has been carried through in the following two parallel steps:

  1. Design of an experimental machine and experimental runs on the machine
  2. Development and test of a new adhesive system using existing production equipment

Carpet squares without PVC is within reach

The conclusion of the development and experimental work is that

  • the cutting/turning unit which is the element of genius in Westbond’s existing production machine can be modified to cut and lay out regular lengths of yarns having a width of 300 mm and a length of minimum 9 mm in periods of at least 10-15 minutes
  • a new adhesive system based on a synthetic latex is provided and laid out on a polyester carrier web which can be used for production of carpet squares having a satisfactory quality
  • contrary to expectation it has turned out to be possible to produce carpet lengths of a satisfactory quality from woollen yarns and with an adhesive system based on a synthetic latex using the sandwich technique, which Westbond has used for producing carpet squares with PVC
  • as expected it has not been possible to produce carpet lengths of a satisfactory quality from synthetic yarns and an adhesive system based on synthetic latex using the sandwich technique
  • a production of carpet squares based on the new adhesive system is assessed to result in lower effects on the working environment and the external environment compared to carpet squares with plasticized PVC. However, the use of the new adhesive system will cause larger energy consumption for evaporation of the water, which is added together with the latex adhesive.

Some of the most important conditions for establishing a production of carpet squares free from PVC have been fulfilled through the results obtained during the development work.

Further tests should be effected

As the positive results have been obtained by short-time testing in pilot or production scale, it has, however, not been documented that a machine in production size will be able to produce the carpet squares developed free from PVC. The basis of a decision on investment in a production plant for producing carpet squares free of PVC is therefore insufficient and should be extended by more experiments.

Environmental Assessment

The applied synthetic latex does not contain chlorine, plasticizers or other environmentally hazardous compounds. Carpet squares with an adhesive based on synthetic latex will therefore cause less environmental effects by disposal than carpet squares with an adhesive based on plasticized PVC.

Plasticizers in indoor air

During use the carpet squares with plasticized PVC will emit small amounts of plasticizers to the indoor air, and that is an unfortunate situation as the plasticizers in question may cause allergy. By using synthetic latex, such a risk does not occur, as no volatile matters are emitted.

Emission of plasticizers

By production of the known carpet squares with plasticized PVC, plasticizers are emitted during curing. As the synthetic latex used for the new carpet squares does not contain volatile matters, apart from water, no environmentally hazardous compounds are emitted.

Excessive consumption of energy

As the new adhesive contains 25-30% water, the production of the carpet squares free from PVC requires an excessive consumption of energy compared to the production of the carpet squares containing PVC for evaporation of water of approx. 0.6 kWh per m2 carpet inclusive backcoating.

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