New fire retardant textiles

Our work focused on Polyamide through the development of an intrinsically flame retarded Polyamide obtained by a copolymerisation of PA monomers with another monomer that can vectorize a phosphorous moieties. With such approach, the problems associated with the spinning of fibres containing mineral additives can be overcome (size migration, stability¿) while imparting flame retardant properties to the materials with low Phosphorous content (such as TREVIRA CS fibres for instance). The critical point here is to find relevant monomers and to fine tune the polymerisation. We have selected in Rhodia Range a dozen of monomers that were copolymerised with Nylons monomers to synthesise oligoamide (short length PA/P copolymer) that are subsequently extruded with PA. Several problems occurred with almost all the monomers (degradation, no Phosphorous in the obtained oligoamide) but we however identified a phosphonic acid that permitted materials to be obtained. The content in residual phosphonic acid was nevertheless too high to achieve processing (depolymerisation in the extruder). After washing, this content was lowered with a successful extrusion and samples were moulded. FR tests (LOI) on these samples showed that a high increase in LOI is obtained (33.5 vs 28% of O2) with less than 1% of Phosphorous. After optimisation of the process, we were able to obtain a yarn, which is a very positive point. Our Process expert thinks however that industrialisation of the route followed with the first acid is likely to be extremely difficult since the yield is too low. We then prefer to stall this route with the phosphonic acid and since we have demonstrated the interest of this copolymerisation route (good FR properties with low P content, spinnability achieved) we now search for new monomers in synthesis that may overcome the problem of yield encountered.

In charge to perform fire behaviour, an alternative plan to treat the polypropylene non woven consists in padding the textile with formulation based on binder resin. The formulation of padding is based on dispersion of fire retardant system based on untumescent concept. A low pick up rate, allows to maintain the softness of textiles. The padding process is adequate for non woven and woven with low density. In this way, the protection of fibre during the combustion is ensuring by intumescent structure. The carbon char issue of degradation of binder resin has clearly 3 functions: - To trap combustion gas in cells, it involves a decreasing a heat release, - To limit thermal transfers in the materials: thermal insulation, - To limit the diffusion of oxygen to the materials. The setting up the treatment is directly interesting for textile industry. It is an opportunity to propose a fire retardant product based on polypropylene totally free of halogen. The potential applications cover a large range of fields: carpet, home furniture, automotive equipment, railways.

Nerefite project focuses on environmental considerations for new flame retardant systems. Flame retarding, especially with non-halogen systems, presents a strong challenge for textile industry. An innovative additive under powder totally free of halogen has been set up with success for treatment of binder resin. The action of this additive, during the degradation of material consists in its interference in the combustion train of binder resin. The high power of dispersion of this additive could allow important development for fire retardant textiles. The setting up of this additive is directly interesting for chemical and textile industry.

A current request from end-users or manufacturers of fire-retardant materials is to have a software able to orient their development in the way they want: reduction of heat release, reduction of smoke production, during combustion of material. A database built with the results from the samples testing during the project has been set up. Software based on statistic analysis by main components has been associated. It allows identifying the main fire behaviour characteristic of a sample, following several parameters. Moreover, this analysis allows associating the technical target wanted by an end-user with the best corresponding requirement in terms of fire retardant additives or processes for example. The interface is chart based from cone calorimeter results and allows a quick and efficient analysis, with a possibility of direct updating from Internet access. This software applies for the moment for transportation, building and home furniture but could be extended to other application fields.

Nerefite project focuses on environmental considerations for new flame retardant systems. Flame retarding, especially with non-halogen systems, presents a strong challenge for textile industry. The incorporation of powder in order to perform fire retardant properties, could involve a lost of mechanical properties. So an alternative is to incorporate fire retardant additives under liquid form. So Devan has elaborated up graded additives under liquid. These additives, incorporated during extrusion step allow to perform fire retardant properties and to increase mechanical properties. The setting up of these additives is directly interesting for plastics and textile industry.

For performing the fire behaviour of synthetic non woven, the first strategy consists in applying a fire retardant back coating formulation or padding formulation to textiles fibres, able to promote a carbon char or to dilute the combustion gas during the thermal degradation. The formulation of back coating or padding is based on the dispersion of phosphorus derivatives, nitrogene derivatives, carbon agent and mineral filler. The development of suitable wet grinding allows increasing the grinding of particle and insures the optimal dispersion. The optimal conditions of wet grinding process allow decrease the quantity of charges and to perform good fire properties with the minimal quantity of additives. The setting up of grinding process is directly interesting for chemical industry and indirectly for industrial, which want to include the nanoparticles in their process. The nanoparticles contribute generally to increase the performance of materials.

The goal of the project is to limit the use of halogenated derivatives as fire retardant additives for synthetic fibres. An alternative plan consists in the use of fire retardant system based on intumescent concept, in which flame retarding occurs in the condensed phase. The intumescent char has a special active role in the process of thermal degradation - combustion of the material: it constitutes a protection shield for the matrix, being a barrier for heat radiation from the flame to the surface of the burning material and for mass transfer of combustible volatiles from the surface of the degradating material to the flame. Flame retarding by intumescence is generally based on the application of 3 basic ingredients: a catalyst, usually phosphates derivatives, a charring agent and a blowing agent. In this project the use of ATH as co-additive to impart thermal resistance to the intumescent formulation has been evaluated. The mechanism of thermal degradation of the binder resin, APP and ATH, as well as the mechanism of their interaction have been studied. Information provided from these studies are fundamental for the optimisation of the formulations. The setting up of the treatment is directly interesting for chemical industry and indirectly for industrials which want to abandon chlorinated and brominated derivatives for textile back coating.

The ultimate goal of Nerefite is to obtain fibres with interesting fire retardant properties using extrusion and spinning devices. Different additives in addition to polypropylene have been studied. We have noticed that one of the limiting parameters in order to obtain fibres is the particles size of additives. The technological tools for grinding is not sufficient in order to decrease the particle size under microns. So Brunel University with the collaboration of Devan has set up an innovative formulation based on injection of fire retardant liquid during the extrusion of polypropylene. This formulation presents two main advantages: - Fire retardant behaviour of polymer are very good. - The mechanical properties of samples are very good. - The setting up of this result is very interesting for plastic industry. Different applications could be envisaged for automotive, building and home furniture.

Objective of the project is to develop specific non-halogeneous fire retardant formulations for PP in fibres applications. The first step of RDT activities was to develop fire-retardant formulations for PP. Different additives were studied and processing was optimized. Formulations based on polypropylene enable to promote fire retardant properties, maintaining polymer mechanical properties. The second step of RDT activities was to optimize these formulations in order to obtain good spinning behaviours at lab and pilot scale. This could be of interest for different final Non-Woven applications, as for instance automotive, building and furnishing industries.

In order to perform fire behaviour, an alternative plan to treat the polyester non woven consists in padding the textile with formulation based on binder resin. The formulation of padding is based on dispersion of fire retardant system based on dilution concept. The additives role consists in its interferences in the combustion train of polymer. The ignition and the degradation of material is limited due to the dilution of combustion of gas. The low pick up rate, allow to maintain the softness of textiles. The padding process is adequate for non woven and woven with low density The setting up of the treatment is directly interesting for textile industry. It is an opportunity to propose a fire retardant product based on polyester totally free of halogen. The potential applications cover a large range of fields: carpet, home furniture, automotive equipment, railways.

In charge to perform fire behaviour, an alternative plan to treat the polyester non woven consists in padding the textile with formulation based on binder resin. The formulation of padding is based on dispersion of fire retardant system based on untumescent concept. The low pick up rate, allow to maintain the softness of textiles. The padding process is adequate for non woven and woven with low density. The protection of fibre during the combustion is ensuring by intumescent structure. The carbon char issue of degradation of binder resin has clearly 3 functions: - To trap combustion gas in cells, it involves a decreasing a heat release, - To limit thermal transfers in the materials: thermal insulation, - To limit the diffusion of oxygen to the materials. The setting up the treatment is directly interesting for textile industry. It is an opportunity to propose a fire retardant product based on polyester totally free of halogen. The potential applications cover a large range of fields: carpe, home furniture, automotive equipment, railways.

In order to perform fire behaviour, an alternative plan to treat the polypropylene non woven consists in back coating the textile with formulation based on binder resin. The formulation of back coating is based on dispersion of fire retardant system based on intumescent concept. In this way, the protection of fibre during the combustion is ensuring by intumescent structure. The carbon char issue of degradation of binder resin has clearly 3 functions: - To trap combustion gas in cells, it involves a decreasing a heat release, - To limit thermal transfers in the materials: thermal insulation, - To limit the diffusion of oxygen to the materials. The setting up the treatment is directly interesting for textile industry. It is an opportunity to propose a fire retardant product based on polyester totally free of halogen. The potential applications cover a large range of fields: carpet, home furniture, automotive equipment, railways.

Deliverables

Share this page

Download