DE4025813A1 - Heat protective material - has inner layer of nonwoven partially graphitised polyacrylonitrile fibres - Google Patents

Abstract

The heat-protection material, with an inner nonwoven or woven layer using fibres which give a high temp. resistance and insulation and which are hard to ignite, and an outer metal foil or metallised surface, uses partially graphitised polyacrylonitrile fibres for the nonwoven (1). The material (1) is then clad with a metal foil (3) or is metallised. Pref. reinforcement yarns (5,6) are worked into the nonwoven (1), in both the warp and weft directions to give 4-24 yarns/inch or 8-10 yarns/inch in the warp direction, and 4-15 yarns/inch or 6-8 yarns/inch in the weft direction. The nonwoven has a wt. of 4-100 g/m2, with reinforcement yarns (5,6) at a rate of 12-200/m2. The polyacrylonitrile fibres have a limiting oxygen index value of at least 40, and the reinforcement yarns along the warp line have a LOI value below 27. The reinforcement yarns (5,6) are of a thermoplastic material, pref. polyester or polyamidimide. ADVANTAGE - The material gives protection against heat, but also gives cover for exposure to flames.

Description

The invention relates to heat protection clothing an inner high temperature resistant, insulating and flame-retardant fabric or fleece made of fibers and an outer metallization or metallized Foil.

Good heat protection clothing should protect against Radiant heat, splashes of liquid metals, Flame contact, contact heat and convection heat represent. At the same time, it should be as far as possible comfortable to wear, mobility of the wearer not so restrict and also mechanically stress be cash, but always a corresponding one  Economy should be given.

Fabric used to be used as heat protection clothing made of asbestos, the outside with a metallized Foil or a metal foil against radiant heat were provided. Because of the health hazard through the use of asbestos today as He substitutes, cotton, wool, linen, glass fibers, kar candy fibers, ceramic fibers, aramid fibers or mixtures used from it.

A disadvantage of these known fabrics or nonwovens is that either the thermal insulation is not for everyone use cases is sufficient or a bad tra comfort is given, possibly both Disadvantages occur together. With a sufficient Heat protection clothing is often too heavy, too rigid and too rigid.

In US-PS 47 48 065 z. B. a flame retardant nonwoven fabric is described, which is impregnated with chemical vapors adsorbing carbon particles. The nonwoven fibers consist of at least 90% aramid staple fibers and the weight per unit area is between 35 and 70 g / m ² . The fibers are consolidated by two water jet treatments, once with a jet pressure of about 1400 kPa, then with jet pressures between 10,000 and 11,000 kpa.

Because this well-known nonwoven is also meltable Possesses fibers, it will be with a direct flame effect destroyed, which is why heat protection clothing This material is only conditionally suitable as heat protection is.

The present invention is therefore based on the object reason to create heat protection clothing that the avoids the disadvantages mentioned above, in particular which provide high heat protection with good wearing comfort and granted with an economy.

According to the invention, this object is achieved in that the nonwoven partially graphitized polyacrylonitrile fibers points, and that the so-equipped fleece with the me metallic foil is provided.

Practical solutions have shown that with a nonwoven of the type according to the invention, basis weights in the range of 70 g / m ² and even lower can be achieved, without the effect of the nonwoven as a flame barrier decreasing. This means that a heat protection clothing made of this material is significantly lighter than the known types. In addition, it has surprisingly been found that the bending stiffness is significantly lower, ie that the fleece according to the invention is more elastic. This means that the heat protection clothing according to the invention has a much better wearing comfort than the known types. The term "partially graphitized" means that the fibers are only graphitized to such an extent that they can still be carded. The LOI value of the fibers used should be between 40 and 65. "LOI" means "Li miting Oxygen Index". This index determines the combustibility of plastics in accordance with ISO standard 45 89 "Determination of the combustibility of plastics by the oxygen index". With certain restrictions, this index can also be applied to textiles if they are made from organic fibers. Effective flame retardant behavior is generally expected at LOI values above about 27.

Practical results have shown that from before is part if the fleece according to the invention in any ner strengthened so that a better tear strength and tear resistance is achieved.

An inventive possibility for this can be stand that ver in the fleece in warp / weft arrangement  running reinforcement threads are incorporated.

In general, it will be sufficient if 4 to 24 threads / inch in the warp direction and in weft direction 4 to 15 threads / cm are available.

In this way, a fleece with a minimum strength of 70 N / 5 cm at a basis weight of 40 to 100 kg / m ² and z. B. a thickness of 1.8 mm maximum, the specified strength is at least present in one direction.

The introduction of the reinforcing threads can be by means of known sewing techniques. Instead of one Full weft binding can also be a short weft binding ten.

The weight fraction of the reinforcing threads can e.g. B. be between 12 and 60 g / m ² . In general, who the strengths achieved in this way be sufficient, of course, if necessary, even higher strengths can be achieved by a corresponding increase in the number of reinforcing threads.

Prerequisite for the use of suitable ver  Strengthening threads is that they also have high LOI values exhibit.

Surprisingly, however, practical results have shown that it is not absolutely necessary ei to take a LOI value of the order of magnitude of LOI value for the fleece is d. H. about 40. It has has shown that you can also z. B. thermoplastic cal plastics, such as B. polyester fibers can, which only have LOI values below 27, the but can be easily processed and very cheap are. Practice has shown that even with these who the flame retardant effect of the fleece or its Strength not noticeably affected by fire is pregnant.

Of course, are within the scope of the invention also other materials for the reinforcement threads possible.

Another way to increase strength, in particular the tensile strength of the fleece can therein exist that the fleece with a second fleece lami niert, whereby one of the two fleeces with the me metallic foil is provided.  

By lamination with a second fleece, egg ne achieved significantly better strength.

A fleece can even be used for the second fleece the same chemical composition as the first Fleece can be used. This is especially true when if you are in the coating or lamination of arrange the two fleeces to each other so that under different strengths in a certain direction different directions can be compensated.

In this way, you can weight the same total area, which is divided equally between the two nonwovens, such as. B. 30 to 50 g / m ² each, a noticeably higher strength with the same basis weight compared to a single fleece with the same total basis weight.

Another way to improve the Festig speed can be that between the fleece and the metallized foil is a grid of high quality temperature resistant and flame retardant material is arranged.

A material will be used for the scrim turn that be a correspondingly high tear strength sits.  

When using two fleeces you can use the grid put on between the two fleeces and put on this way an even higher strength of the textile received material for the heat protection clothing.

As a very cheap material for the scrim carbon fibers have shown up.

As an adhesive for lamination or coating the individual components with each other z. B. Adhesive based on polyester or polyurethane is used will.

It is advantageous if the adhesive flame protective agents are added, such as B. mineral Flame retardants that release carbon dioxide and water ten. B. hydroxides or carbonates net.

Likewise, organic bromine ver are used as flame retardants bonds, optionally combined with antimonyoxy the, suitable.

The proportion of the flame retardant in the adhesive can according to the invention between 20 and 40 percent by weight  be.

Below are based on the drawing and together some examples for the he heat protection clothing according to the invention described.

It shows:

FIG. 1 is fragmentary enlarged view of a section through an inventive web which is connected to a metallized film, which is provided with a carrier film;

Fig. 2 shows an embodiment in an enlarged Dar position with two nonwovens according to the invention and a metallized film;

Fig. 3 shows another embodiment in an enlarged view with two nonwovens, a scrim arranged between them and egg ner with a carrier film provided metallized film.

Composition example 1

For the example of FIG. 1, a fleece 1 of 70 g / m ² , made of partially graphitized polyacrylonitrile staple fibers with an LOI value of 60 and a titer of 1.7 dtex in an isotropic fiber orientation, in two stages with columnar Water jets solidified. There are 5 nozzle bars in each stage, whose holes have a diameter of 120 µm, and which are arranged at intervals of 0.6 mm.

In the first stage, the top of the fleece is covered by Nozzle bar to jet beam increasing jet pressure, solidified starting at 25 bar, ending at 140 bar.

The water jets work with a pressure of approx. 10,000 kPa on the fibers. However, it is also possible Lich, multi-stage and continuous printing down to 14,000 kPa to increase.

In the second stage, the fleece is on its bottom side solidified, whereby here the pressures of nozzle bal staggered to form nozzle bars from 80 bar to 140 bar are.

In both stages, the fleece is placed on a sieve belt transported with 100 mesh to form a fabric  to get a closed surface.

The fleece is then treated with a hydro and oleophobia commercially available fluorocarbon resin soaks that 27% resin remains on the fabric.

The fleece 1 obtained in this way is coated on one side with a polyester or polyurethane adhesive: a first coat can be applied as a primer, in order to achieve better smoothing, especially on rough surfaces. Subsequently, a second line is applied and a metallized film or layer 3 is placed on the adhesive 2 obtained in this way. Of course, the first stroke can also be applied as adhesion to the metallized film, specifically on the side facing the fleece 1 .

The lamination or lamination of the fleece 1 with the metallized film or layer 3 can be known in a known manner under a correspondingly applied surface and at elevated temperatures, for. B. 110 to 120 ^o take place. As a metal for the metallized film z. As aluminum, gold or silver who used the. For cost reasons, however, aluminum will generally be used for this.

The metallized film 3 can with a carrier film 4 , z. B. made of a polymer. The carrier film 4 is peeled off after the metallized film 3 has been applied to the fleece 1 .

In this way you get a light and very fle xibles material for heat protection clothing.

Practical results have shown that at same heat protection values weight savings between between 30 and 700% are possible at the same time lower bending stiffness or better flexibility lity, which also makes it easier to assemble is given.

To increase the strength, the fleece 1 can also be provided with reinforcing threads 5 that run in the warp direction and reinforcing threads 6 that run in the weft direction. It can be embedded in the warp direction 9 reinforcing threads 5 / inch and in the weft direction 7 reinforcing threads 6 / cm.

The reinforcing threads 5 and 6 can be reinforced with a magazin shot weft machine with a fleece template with polyamide imid warp yarn and a weft yarn on the same basis with a distance of 3 mm in the warp and a spacing of 35 mm from the weft. The yarn count in this case is 80 dtex.

Composition example 2

According to example of Fig. 2, a first web 1 A and 1 B, a second web are provided, each having an area weight of 35 g / m ^2, 100% partially graphitized polyacrylonitrile fibers having decitex of 1.7, which with Card and cross layer stored and then water jet strengthened according to the conditions specified in composition example 1. May comprise by an adhesive 2, the game, the sliding surface as in the composition Zusammensetzungsbei of FIG. 1, with the webs 1 A and 1 B are joined together. This can be achieved by lamination in a continuous press. If the two fleeces 1 A and 1 B are laid on top of each other in different ways according to their fiber course, the same strength can be achieved in all levels. This means that the bond between the two fleeces 1 A and 1 B can be stretched equally far in all directions.

Adhesive 2 is again applied to the free surface of the web 1 A and laminated a metallized foil. 3 In contrast to composition example 1, the metallized film 3 is thicker in this case and not provided with a carrier film. As a metallized film z. B. a rolled aluminum foil can be used for this. In this way, the unit is stronger and more resistant to bending, but it can also be loaded even more and so z. B. use as face protection.

A further possibility for a coating of the web 1 or the two webs 1 A and 1 B also consists in that one carries out a direct Bedamp evaporation under high vacuum and in this way a direct metallization makes Me or metal particles as a layer or film on the Applies fleece.

Composition example 3

The example shown in Fig. 3 is fundamentally Lich of the same structure as the two compositions above be traded.

The only difference is only that between the two fleeces 1 A and 1 B a scrim 7 is inserted, which serves for reinforcement and z. B. can consist of carbon fibers. In this case, a metallized film 3 with a carrier film 4 is again shown, wherein of course a metallized film 3 without a carrier film can also be used in this case.

Claims (23)

1. Heat protection clothing with an inner, highly temperature-resistant, insulating and flame-retardant fabric or fleece made of fibers and an outer metallization or a metallized film, characterized in that the fleece ( 1 , 1 A, 1 B) has partially graphitized polyacrylonitrile fibers , and that the so equipped fleece ( 1 , 1 A, 1 B) is provided with the metallized film ( 3 ) or metallization. 2. Heat protection clothing according to claim 1, characterized in that in the fleece ( 1 ) in warp / weft arrangement duri fende reinforcing threads ( 5 , 6 ) are incorporated. 3. heat protection clothing according to claim 2, characterized in that 4 to 24 threads / inch in warp direction and in weft direction 4 to 15 threads / cm are available. 4. heat protection clothing according to claim 3, characterized in that 8 to 10 threads / inch in warp direction and in weft direction 6 to 8 threads / cm are available. 5. Heat protection clothing according to claim 3 or 4, characterized in that the basis weight of the fleece ( 1 ) is between 40 to 100 g / m ² and the reinforcing threads ( 5 , 6 ) are present in an amount of 12 to 200 m ² . 6. Heat protection clothing according to one of claims 2 to 5, characterized in that the polyacrylonitrile fibers have a LOI value of at least 40 and at least the reinforcing threads ( 5 ) running in warp direction have a LOI value of less than 27. 7. Heat protection clothing according to one of claims 2 to 6, characterized in that the reinforcing threads ( 5 , 6 ) consist of thermoplastic material. 8. heat protection clothing according to claim 7, characterized in that the thermoplastic material is polyester. 9. Heat protection clothing according to claim 6, characterized in that the reinforcing threads ( 5 , 6 ) made of polyamide imide be. 10. Heat protection clothing according to claim 1, characterized in that the fleece ( 1 A) with a second fleece ( 1 B) is laminated, and that one of the two fleeces ( 1 A, 1 B) with the metallic foil ( 3 ) is. 11. Heat protection clothing according to claim 10, characterized in that the two fleeces ( 1 A, 1 B) have at least approximately the same chemical composition. 12. Heat protection clothing according to claim 10, characterized in that the second fleece (1B) aramid fibers, glass fibers, Carbon fibers, flame retardant cotton fabric, Kera contains microfibers or mixtures thereof. 13. Heat protection clothing according to one of claims 1 to 9, characterized in that between the fleece ( 1 ) and the metallized fo lie ( 3 ) a scrim ( 7 ) made of high temperature constant and flame-retardant material is arranged. 14. Heat protection clothing according to one of claims 10 to 12, characterized in that between the two fleeces ( 1 A, 1 B) a lattice layer ( 7 ) made of a high temperature-resistant and flame-retardant material is arranged. 15. Heat protection clothing according to claim 13 or 14, characterized in that the scrim ( 7 ) has carbon fibers. 16. Heat protection clothing according to one of claims 1 to 15, characterized in that the adhesive ( 2 ) for coating the fleece ( 1 ) or the fleece ( 1 A, 1 B) with each other and the metallized film ( 3 ) on polyurethane or polyester base. 17. Heat protection clothing according to claim 16, characterized in that the adhesive ( 2 ) mineral and / or organic flame retardants are admixed. 18. Heat protection clothing according to claim 17, characterized in that the adhesives ( 2 ) are carbon dioxide and / or water-splitting substances, such as hydrooxides and / or carbonate te. 19. Heat protection clothing according to claim 16, characterized in that as a flame retardant, organic bromine compounds, especially combined with antimony oxides, beige are mixed. 20. Heat protection clothing according to one of claims 17  until 19, characterized in that Flame retardants in an amount of 20 to 40 % By weight are added. 21. Heat protection clothing according to one of claims 1 to 20, characterized in that the metallized film ( 3 ) is provided on the outside with a carrier film ( 4 ) which can be peeled off after coating. 22. Heat protection clothing according to claim 21, characterized in that the carrier film ( 4 ) is made of a polymer. 23. Heat protection clothing according to one of claims 1 to 20, characterized in that the metallized layer or film ( 3 ) is applied to the fleece ( 1 ) directly by vapor deposition in a high vacuum.