DD251579A5 - METHOD FOR PRODUCING FLAME-RESISTANT MATERIALS - Google Patents

Abstract

A method for producing a flame resistant combination of at least two flame resistant staple fiber components in sliver, roving, single or multiple, woven or knitted fabric form. The combination is intended for the manufacture of apparel, apparel or apparel systems which include, predominantly or at least partially, fabrics having threads with segregated components. The object is to produce flame-resistant material which has a low heat shrinkage under the action of flames and intense heat while maintaining its flexibility and a certain degree of strength and in which only a slow tearing occurs. This is accomplished by keeping one of the components of the combination separate, positive, or otherwise intentional from the other component or components of the combination.

Description

For this 2 pages drawings

Field of application of the invention

The invention relates to a process for producing flame-resistant materials, which are particularly suitable for withstanding the effects of relatively high temperatures.

Characteristic of the known state of the art

It is known to use protective clothing to protect people who are unintentionally or otherwise exposed to conditions of extreme heat flow or flames with very high temperatures. A primary function of protective apparel is to protect the wearer from the effects of extreme heat and flames for as long as possible, or, in an emergency, at least as long as may be required to reach the extremes where the extreme temperatures occur. to escape to a place with a lower and more acceptable temperature level. In particular, any protective clothing should shield the wearer's body for as long as is necessary to enable the survival of a person exposed to extreme temperatures.

For persons whose profession includes the possibility of being exposed to extreme heat and flames from very high temperatures, such as army personnel, aircraft or ground personnel, racing drivers, police officers, firefighters, workers in certain industries, one must always be aware that this person at any time, z. B. by an accident or as a result of conscious actions, eg. B. by the enemy, heat and flames can be exposed to extreme temperatures. In these cases, every second counts because a person who is in danger will try to escape, but will need a certain amount of time.

At the same time, these individuals are required to be able to move relatively freely for extended periods of time without being unduly hampered by the protective clothing. In other words, portability, d. h., the aspects of comfort of the materials from which the clothes are made must be taken into account. From this it can be deduced that the material of a protective garment can consist of more than one fabric layer, wherein the first layer, the outer layer, must be capable of shielding or protecting against heat and flames, while a second layer serves for a Insulation layer that retards the penetration of heat through the clothes on the wearer. In this context

It should be noted that in cases where the wearer 's clothing consists of several pieces, the thermal insulation concerns not only the outer garments (ie the garments which are traditionally considered to be protective clothing), but also the underwear of the Carrier, since it also offers a degree of thermal insulation.

Depending on the place of use, i.e., depending on the prospect of occurrence of calamities and the environmental aspects, it is necessary to choose between different insulation compromises, that is, to be made.

The insulation is made by the entire clothing system or is to be realized by this, d. H. usually by more than one layer of fabric made of the same or different materials.

In practice, the outermost layer of a protective clothing system can be considered as the most important part of the protective clothing, since this layer must withstand most of the effect of extreme heat conditions and, as already mentioned, this layer as a shielding layer not only with respect to the body of the wearer, d. h., his skin, but also as a protective agent for the insulation that provide the layer or layers of clothing must serve.

It has been found that the fabric used to make the shielding layer must meet very specific conditions. First and foremost, the material must be flame-resistant. That is, the material must have an oxygen limit index (LOI) of at least 26.5 in fabric form. In other words, the material must be self-extinguishing when the ignition source is removed (Textile Chemist & Colorist, Vol. 6, No. 2, 1974, pp. 25 to 29). In addition, when subjected to intense heat flow, it is necessary to maintain the material as an uninterrupted surface as long as possible.

Many proposals have been made for materials that have flame resistant properties. Thus, natural or artificial fibers were proposed. These fibers include, for example, cotton, wool, rayon, and / or proteinaceous fibers which have been fabricated after manufacture to reduce flammability.

It is already known, artificial or synthetic fibers, eg. B. viscose fibers, polyester and Akrylfasem, which are normally flammable, make it non-flammable that flame-retardant additives were included during manufacture. It would also be suggested to make staple fibers from polymers that are flame resistant per se. These staple fibers include polyvinyl chloride, polyimide, polyamideimide, polytetrafluoroethylene, polyacrylonitrile and polymetaphenylene isophthalamide, etc.

For the sake of simplicity, flame resistant fibers in this specification are referred to as FR fibers.

Another group of fibers characterized by materials such as the following is referred to as a fiber group having flame resistant properties: polybenzimidazole (PBI fiber); Polyparaphenylene terephthalamide (KEVLAR fiber and TWARON fiber); Formophenol resin fiber (PHILENE fiber); crosslinked polyacrylic acid (INIDEX) and certain heat-treated / cyclized acrylic pulps (carbonized fibers). This group of materials will be referred to hereinafter as R-fibers.

In general, it has been found that FR fibers, after spinning into yarns and weaving into fabrics, show considerable deterioration or high heat shrinkage and rapid "break-up" under the action of flame and intense heat. Tissue-form fibers are capable of withstanding intense heat flow over a considerable period of time with far less heat shrinkage and without "break-up" or delayed "break-up", coupled with the maintenance of their flexibility, accompanied by a degree of strength over a much longer period of time / as is the case with FR fibers under the same conditions.

Despite the apparently better possibilities of R-fibers compared to FR-fibers, the R-fibers have not found a general input into the production of protective apparel, since it has been found that R-fibers have certain properties which prohibit the use of R-fibers restrict the weaving of protective clothing.

For example, the tentative use of R-fibers is based on poor dyeability and, in some cases, inherent light color and poor lightfastness. Even mechanical properties such as abrasion resistance are not optimal for everyday wear.

It is already known from US Pat. No. 4,198,494 to provide an intimate mixture of fusible FR fibers and R fibers for the production of a protective clothing fabric. In the specification of this US patent, a fusible FR / F fiber blend having at least 15% FR fibers and at least 3% R fibers is proposed. In this mixture, the individual fibers are not preferentially segregated in certain areas of the mixture, as might occur due to normal variations in fiber distribution which would be expected on a purely statistical basis. It has been found that the fabric made from this blend has a synergistic tensile strength effect at a heat flux of 8.4 J / cm ² for ten seconds (ie, 2cal / cm ² ), hereinafter referred to as " The term "synergistic" is used in the US patent in the sense that the strength of a fabric made from the blend in the condition of flames is substantially higher than the sum of the strength proportions of the individual Components of the fabric when they are in flames.

It is also known from U.S. Patent 4,198,494 to use a modified flame test for the testing of FR and R fibers.

The test was used to investigate the extensive fusion between the fibers and the so-called "flame resistance" as the strength of the fabric in the condition of flames.

It has been found that this test lacks accuracy and reproducibility in the measurement of flame resistance.

This is particularly true when testing very lightweight fabrics such as the "residual fabric" mentioned in Example 1 of the above-referenced U. S. The sudden heat flux of 2cal / cm ² (8.4J / cm ² ) through a Meker burner is also too sudden and too intense, and the strength of the flame interferes with the measurement.

Object of the invention

The aim of the invention is to produce flame-resistant material with high performance properties.

-4- 251 579. Presentation of the Essence of the Invention

The invention has for its object to produce flame-resistant material from a combination of at least two staple fiber components in a sliver, roving, single or multiple yarn or in the form of a woven or knitted fabric, in the action of flames and intense heat while maintaining its flexibility and a certain degree of strength has a low heat shrinkage and in which only a slow tearing occurs.

This is inventively achieved in that one component is deliberately, positively or otherwise intentionally kept separate from the other component or components of the remaining combination.

According to another aspect of the invention, there is provided a method of making a flame resistant combination of at least two flame resistant staple fiber components in woven or knitted form, characterized in that one of the components is intentionally, positively or otherwise intended by the other component or components of the combination is kept separate in such a way that the "thermal behavior properties" are related synergistically to the corresponding properties of the individual components

The components are assembled such that one of the components is in the form of a roving and the other component is in the form of a sliver. The roving component is used torsion-free.

The components are assembled such that the combination in yarn form contains the one component concentrated in the core of the yarn.

Preferably, the components are assembled such that the combination in multiple yarn form includes at least one twist with the one component. The components are assembled such that the combination in multiple yarn form includes at least one twist prepared according to the invention.

Preferably, the components are assembled so that this combination, in a woven form in the warp and weft directions of the fabric, has flame resistant yarns containing that component, the flame resistant yarns being separated by a maximum of twenty times the thickness of the fabric.

The components are assembled such that the combination in the form of a fabric in the warp and weft directions of the fabric includes flame-resistant yarns consisting of a combination of at least two components joined together according to the invention, the flame-resistant yarns being separated by a distance, which has a maximum value of twenty times the tissue thickness. One component has a thermal behavior with a maximum of 15mJ / dTex.

Polyparaphenylene terephthalamide and / or formophenol and / or polybenzimidazole and / or carbon fibers are preferably used for the one component.

For the other component or components natural and / or artificial materials are used which are flame-retardant, such as wood and / or cotton and / or viscose silk and / or protein staple fibers.

For the other component or components, artificial material including flame retardant additives such as viscose silk and / or diacetate and / or triacetate and / or protein staple fibers may also be used.

Further, for the other component (s), synthetic / organic materials including flame retardant additives such as polyester and / or polyamide and / or polyacrylonitrile staple fibers may be used.

Flame resistant material, such as modacrylic and / or polyvinyl chloride and / or polyimide and / or polyamide imide and / or polytetrafluoroethylene and / or polymetaphenylene isophthalamide and / or crosslinked polyacrylic acid fiber, is inherently used for the other component or components.

According to the invention, one component is used in a proportion of between 2 and 4, or 0.5 and 40, or 0.15 and 5% by weight to the total weight of the combination.

embodiment

The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawing show:

1 shows a schematic representation of the apparatus for testing the properties of the heat-resistant materials produced according to the invention;

FIG. 2 is a schematic side view of the apparatus of FIG. 1; FIG.

Figures 3 and 4 are graphs illustrating the mutual relationships of defined material factors of the invention and known technical solutions.

Referring now to Figs. 1 and 2 there is illustrated an apparatus used for accurate testing to determine the properties of refractory materials. The test method was developed because it is questionable in relation to the description of US Patent 4198494 whether the measurement of "flame resistance" is a measure of the "thermal behavior" of the fabric to serve as the protective layer. The term "thermal behavior" is discussed in more detail below: Given the people who are still able to escape from the area where the extreme temperatures occur, it is proposed, according to a realistic viewpoint, to reduce the heat flow to half the lower limit of the lower temperature range at a fuel oil conflagration (3.2 J / cm ² s). in the present invention (not shown) in place of the convective heat of a Meker burner is used, the radiant heat of a quartz tube 1 of 500 watts. the current that this quartz tube 1 can be changed by a transformer (not shown) to obtain a heat flux of 3.2 J / cm ² s. As shown in Fig. 1, a 20 mm wide cloth strip 2 of the test fabric is allowed to pass from a metal strip 3 hang down, which is located above the quartz tube 1 and is fastened by means of a fastening element 4 on the metal strip 3. Diese Gewebestr 2 is kept outside the area of the quartz tube 1 until the test begins. On the fabric strip 2 is at the lower end 6 with a fastening element 7 a

Reference weight 8 is attached, which weighs 20 g in the present case. The fastener? can cooperate with a device 5 to keep the tissue away from the quartz tube 1. As can be clearly seen from FIGS. 1 and 2, the fabric strip 2 winds around only a portion of the quartz tube 1. In practice, it is necessary that the chord length 9 of the winding, the contact length between the fabric strip 2 and the quartz tube. 1 is 7 mm. This is shown in Fig. 2.

In U.S. Patent 4,198,494, "flame resistance" is measured by maintaining a fixed flame time in seconds and applying different weights to the fabric strip By using the quartz tube 1 and fixed reference weight 8, the time during which the fabric is exposed to heat flow is measured before it can no longer carry the fixed weight (for example, it is assumed that the required time is effectively a characteristic of the amount of Joule heat flux.)

Consequently, the device (opening) 5, which shields the fabric strip 2 and keeps out of the area of the quartz tube 1, can be withdrawn. The fabric strip 2 swings toward the quartz tube 1, and an area of 1.4 cm ² comes into contact with the quartz tube 1, the area to which the above chord length 9 refers. As a result, the fabric strip 2 is exposed to a heat flux of 4.5 J / s. There is a timer to measure the time needed for the reference weight 8 held by the fabric strip 2 to fall down.

This thermal behavior test can be used to calculate the amount of heat flow that can withstand the tissue as the "thermal behavior" of the fabric.

This amount of heat flux in Joules can be divided by the Tex total value (denier) of all the yarns running in the vertical (test) direction to calculate the heat behavior of the test fabric per decitex (dTex) in millijoules (mJ) ,

The thermal performance test also determines the time that is so important in escaping from the effects of extreme heat and flames. Since every second that a person can move from the place of heat and flames is important, every extra second increases the chance of survival.

To determine if a fiber is suitable as an R-fiber component, a fabric made from this fiber may be subjected to the test of the invention set out above. If the "thermal behavior" per decitex is at least 15mJ, the fiber may be considered R fiber.

For a study of the synergistic effect mentioned in U.S. Patent 4,198,494, the following test fabrics were made using various intimate blends of FR and R fibers.

The FR component used was a 40 mm (1.6 inch) fiber length and 1.7 decitex (1.5 dpf) fiber fineness (APYEIL) meta-tag fiber (polymetaphenyl isophthalamide fiber).

The R fiber used was a para-aramid fiber (polyparaphenylene terephthalamide fiber (KEVLAR fiber). The chamfer length was 38 mm (1.5 inches) and the fiber count was 1.7 decitex (1.5 dpf) Different amounts of these fibers were mixed in fiber form and made into a single yarn of 49Tex (12cm ³⁾ spun. The yarns were woven into a plain weave fabric of about 21x21 threads per cm after removing sizing components and dirt. The basis weight of these fabrics was in the range of 227-241 g / m ² (6,7- 7.1 ounces / square yard).

The "thermal behavior" of these fabrics was measured and is shown in Table 1. The data of the intimate blend of Table 1 are shown in Curve A of Figure 3.

Table 1 thermal behavior Synergistic effect composition (MJ / dtex) Compared with 100% % FR /% R) R-fiber 0.9 negative 100/0 24.6 45% 95/5 23.5 38% 90/10 21.3 25% 80/20 20.5 20% 67/33 17.0 0% 0/100

It is important to note the differences between these numbers and the flame resistance measurements mentioned in U.S. Patent 4,198,494. According to the US patent, 100% para-amide (KEVLAR) numbers of "flame resistance" give a far higher "heat performance" than the 100% meta-aramid fabric, i.e., 100%. h., 17.0 mJ / dTex, compared with O, 9mJ / dTex.

To better understand the data in Table 1, it should be noted that in practice these numbers correspond to 78s break time and 4s break time for these fabrics. The figures also illustrate the synergistic interaction between the fibers in the intimate mixture.

This is totally unexpected and is in contrast to the flame resistance figures in the US patent.

It can be seen from Table 1 that the synergistic effect, as understood in the present invention, is the ratio of the "thermal behavior" of the intimate blends for fabric compared to the "thermal behavior" of 100% R-fiber fabrics, ie, fabrics, 100% made from the best of the two components. The "thermal behavior" of all intimate fiber blend fabrics is better than that of the 100% paraaramid fiber fabric and it can be seen that the synergistic effect increases with the reduction in the amount of paraaramide.

The accurate thermal performance testing developed in the context of the present invention also demonstrates the accuracy of the 3 to 20% blend range embodiments set forth in the U.S. Patent. It is shown that the increase in the synergistic effect when using more than 20% paraaramide in admixture with metaaramide is far less than the synergistic effect that can be achieved at mixing levels below 20%. This is shown in the lower curve A of FIG.

The 20% blend value in the U.S. Patent was chosen for practical reasons of dyeability, abrasion, and the like. As has now been demonstrated, the value of 20% is an important limit of the effective effect of the fiber component.

As noted in U.S. Patent 4,198,494, the lower limit of 3% for the R-fiber component was chosen as a practical minimum for intimate blends to ensure uniform distribution of the R-fiber component in the blend. The effectiveness of mixture values below 3% is referred to below. According to the invention, it has been found that the positive, deliberate or otherwise intended separation of the R fibers in a flame-resistant combination of flame-resistant fibers gives rise to an unexpected synergistic effect which can not be explained by the sizing action of the fusible FR fibers, as disclosed in US Pat. Patent 4198494 is done. The need for the presence of fibers having a sizing effect will be discussed below

Referenced. , - -

In order to make comparisons of the U.S. patent and those of the present invention, a 49 tex (12cm ³ ) yarn of 90% meta-aramid (APYEIL) and 10% paraaramid (KEVLAR) was spun on a DREF spinning machine, in which every 10% of KEVLAR para-amide fibers were deliberately sequestered in fiber form in the core of the yarn.

The yarn was woven into a linen weave fabric to produce a fabric piece of 21 × 21 threads per centimeter, which is comparable to that of a 90/10 blend of yarns.

The comparison of the "heat performance number" per decitex in the fabric of the present invention with the

"Tissue Thermal Behavior" for the fabric of the U.S. Patent is shown in Table 2.

For the sake of simplicity, in the following specification, intimate blend yarns will be referred to as I-yarns and the segregated yarns of the present invention will be referred to as S-yarns.

Table 2

Mixing method Thermal behavior Synergistic effect

(10% R) (mJ / dTex) compared to 100%

R-fiber

Intimate (I) 23.5 38%

Separate (S) 32.7 92%

As shown in Table 1, the "thermal behavior" of the I-Gamen fabric with a 10% R-fiber content has a synergistic effect of 38% compared to the "thermal behavior" of 17mJ / dTex of 100% R-fiber. When the R-fibers are positively, consciously or otherwise intentionally segregated at the core of the S-Game, a synergistic effect of 92% is obtained which is about two and a half times that of the I-yarn.

It is to be understood that the embodiments of the present invention are not limited to combinations of only two staple fiber combinations, but also include multiple combinations of components, e.g. B. multi-FR and R components, work to achieve the required percentages of each type.

On a DREF spinning machine, a yarn is spun to 49 tex (12 cm ³ ) containing 63% APYEIL meta-amide fibers (FR fibers) 27% non-fusible, flame-retardant viscose FR fibers and, when segregated, 10% KEVLAR para-aramid fibers ( R fibers). The yarns are then woven into plain weave fabric at 21-21 threads per centimeter (thr / cm) after desizing.

The thermal behavior is measured and gives a value of 40.5 mJ / dTex, which shows an improved synergistic effect compared to the yarns with a 10% R fiber content in Table 2; see Table 2 A.

Table 2A % R fibers thermal behavior synergistic (MJ / dtex) effect yarn type 100% 17.0 0% ring-spun yarn 10% 23.5 38% Intimate mixture 10% 32.7 92% segregated Viscose 10% 40.5 138% Segregated + 27%

Another method of scouring the R-fibers in the core of a yarn is to spin only a very fine yarn of R-fibers or the use of a continuous yarn of R-fibers. Using the known core spinning techniques, the pre-spun R fiber or R-fiber continuous yarn can be segregated in the core of the yarn.

The spinning can be done with any spinning machine that is suitable for spinning very fine yarns. Core spinning may be accomplished using the known core spinning techniques, ie ring spinning, rotor spinning, friction spinning, etc. A very finely spun yarn of 100% KEVLAR® para-aramid (R-fibers) was spun into a 12 tex (50cm ³ ) yarn.

On a DREF friction spinning machine, the above yarn was incorporated into the core of a yarn of APYEIL® meta-aramid fibers (FR fibers) to form a 49-tex yarn having an R-fiber content of 24%. Also from this yarn was woven a plain weave fabric with 21 χ 21 threads / cm, washed and tested.

The value of the "thermal behavior" of this fabric is 22.5 mJ / dTex, which corresponds to a synergistic effect of 32%.

As is clear from Table 1, the synergistic effect of an intimate mixture of 20% R fibers is 25% and decreases as the proportion of R fibers is increased. Consequently, an intimate blend with an R-fiber content of 24% (I-yarn) has a synergistic effect of less than 25%. For an S-yarn with an R-fiber content of 24% is the

j synergistic effect 32%, which is far higher and the increased synergistic effect of segregated inclusion and

R-fibers underline.

As shown in Table 1, the synergistic effect increases as the amount of R fibers in the fabric decreases.

The reduction in the amount of R fibers is achieved by reducing the amount of R fibers in the yarns. Another way to reduce the amount of R-fibers in the fabric is to use different yarns with one

different proportion of R-fibers. A fabric may be made from the above-mentioned S yarn having 24% R fibers in combination with J yarn having 0% R fibers, and the yarns may be used sequentially. In other words,

if one of two yarns in the fabric contains 24% R fibers, the total amount of R fibers in the fabric is 12%.

Consequently, the segregation of the R fibers can be made not only in the yarn, but also during the weaving of the fabric, wherein a feature of the present invention can be seen.

Using the above-mentioned S-yarn (S) containing 24% R-fibers in combination with a yarn (FR) also prepared on the DREF spinning machine and containing 0% R-fibers, various fabrics became 49 x 49 tex and 21 x 21 thread / cm and, after desizing, tested to determine "thermal behavior." The results are shown in Table 3 and in Curve B in FIG.

Table 3 % R fibers in thermal behavior synergistic Used yarn tissue (MJ / dtex) Effect,% 0.0 1.3 negative All FR yarns 4.8 37.0 118 1S- + 4 FR-G. 8.0 30.7 80 1 S + 2 FR-G. 24.0 22.5 32 All s-yarns

As can be seen, as the amount of R fibers in the fabric decreases, the amount of R fibers in the particular S yarn containing the R fibers remains constant (24% ). Thus, the increased synergistic effect achieved by the deliberate segregation of the R fibers in the yarn, rather than intimately blending, can also be achieved by segregating R fiber-containing yarns in the fabric. The tissue thickness of the tissues mentioned in Table 3 is between 0.51 and 0.52 mm. For the fabric of 1S and 4FR yarns, the distance between two S yarns is 2.30mm. Thus, the S yarn separation distance can be defined as the ratio of 4.5 times the fabric thickness. Increasing this distance also increases the risk that a small piece of fabric, bounded by S yarns in the protective and warp directions, will break up. Thus, depending on the thermal behavior and other properties of the other component or components, the spacing between two R-fiber containing yarns is limited and must not exceed twenty times the fabric thickness.

It is known that single yarns can be twisted or twisted. To deliberately segregate the R fibers into the yarn, two or more yarns can be twisted, of which at least one yarn (which is only very fine compared to the other yarn components with which it is to be twisted) has R fibers ,

As an example, the above-mentioned 10% KEVLAR® para-spandex yarn (R-spun yarn) having a yarn count of 12Tex can be twisted with a 10% APYEIL meta-filament yarn (FR-fiber yarn) having a yarn count of 37 Tex, thereby forming a multiple yarn combination with a yarn count of 49 Tex, where the amount of deliberately segregated R fibers is again 24%.

Also yarns of FR-fibers can be twisted with at least one yarn of a combination of FR and R-fibers, in which the R-fibers are deliberately segregated. This method is preferred to a reduction in the amount of R-fibers and makes it possible to eliminate the step of pre-spinning very fine yarns of R-fibers. According to a further aspect of the invention there is provided a flame resistant combination of at least two flame resistant staple fiber components in the form of a multifilament wherein at least one of the components is deliberately, positively or otherwise intentionally segregated and at least one twist is the R fiber or a combination of FR and R Contains fibers in which the R fibers are deliberately segregated.

The above-mentioned S yarn containing 24% R fibers is a yarn in which the R fibers are contained in (pre-spun) yarn form.

As shown above, the "thermal behavior" increases as a function of the reduction in the amount of R-fibers. When working with the roving system, the low percentage of R-fibers can only be achieved with fairly coarse yarns (thick yarns). there are limits to the fineness of the pre-spun yarn.

The segregation of the R fibers can also be achieved in fiber form as in the S yarn in Table 2, so it is not the form of Vorspinnens required. As already stated, an S yarn with 10% segregated R fibers was spun on a DREF spinning machine. In this case, the R-fibers are not pre-spun, but included in the yarn in the form of a fiber. The fiber insert in the warp part of the machine was a fiber sliver of FR fibers and a roving of R fibers. In the warp zone, the fiber insert, i. h., The sliver and the roving, warped, but remains in relative order. Consequently, the R-fiber structure is only pulled into a finer fiber bundle and remains segregated. This system is referred to as sliver roving mating system and forms another aspect of the invention.

Also in the (conventional) ring spinning systems, the sliver roving mating system can be used to obtain segregated R fibers in a ring spun yarn.

By using the sliver-roving mating system as an insert in the fine flyer to obtain a roving with segregated R-fibers, which results in a ring spun yarn with segregated R-fibers after spinning on the ring spinning machine. As is known from ring spinning technology, the last machine in the overall process that mixes fiber blends is the stretching machine.

By repeatedly combining six or more slivers and stretching into a sliver, blending or blending of the fibers occurs. Example 1 of U.S. Patent 4,198,494 achieves intimate mixing on these machines.

When working with the sliver roving mating system, no mixing occurs on the last stretching machine when an R-fiber process (in the middle of the other fed slivers) is introduced into the machine. Consequently, the output from this last stretching machine and the insert into the next machine, the Feinflyer, a sliver with segregated R-Fasem. After spinning the roving on a ring spinning machine, a ring spun yarn with segregated R fibers is obtained.

In another aspect of the invention, a method is provided for incorporating segregated R fibers into a flame resistant fiber yarn through a sliver roving mating system.

When the sliver roving system is applied to the last stretching machine as mentioned above, the amount of R fibers can be very small because the machine feeds six or more slivers of FR fibers and a roving of R fibers becomes. There may be a percentage of 2 or, if worked with a twistless roving as described below, even less than. one percent can be achieved.

When the fiber bath roving mating system is to be applied to a machine in which the insert consists of only a single sliver, i. i.e., a prefiller, a DREF friction spinning machine, etc., the lower limit of the percentage of the R fibers may not be so low because there are practical limitations on the fineness of the roving. It is therefore a further feature of the invention to provide a particular sliver roving mating system in which the roving member consists of a twist-free fiber bundle made according to a twist-free spinning system known per se.

Such twistless spinning systems are referred to in Dutch Patent 143002; in British Patent 1186233; in U.S. Patent 3,447,310; in Japanese Patent 805398 and also in British Patent 1419108. Essentially, these systems involve stretching a sliver into a finer fiber bundle and, instead of twisting to consolidate the bundle, bonding the fibers through a water soluble glue. The twist-free "yarn" spun according to these systems can be used as a process in the sliver-roving mating system if the amount of size used in these systems is reduced to a level that does not interfere with stretching of the fiber bundle in the draw area.

From statistical considerations, it is known that for intimate fiber blends the blending level has a practical lower limit of 3% specified, but in practice this is an actual limit of 5% to ensure the likelihood of the occurrence of R-fibers; h., the uniform distribution of the R fibers. This possible practical limit is also cited in U.S. Patent 4,198,494. Due to the deliberate segregation of the present invention (ie, no intimate bond), the limit for the combination of two or more fiber components to ensure the likelihood of R fiber occurrence is less than 3%, and may vary depending on the fiber fineness and Yarn number, even less than 0.5%.

Using APYEIL metaaramide FR fiber and KARVAR paraaramide R fiber, a single ring spun yarn with a yarn count of 49 Tex is made and woven into a plain weave fabric of 21 × 21 yarns per centimeter. At the last stretching machine, the sliver roving mating system is used to obtain yarns comprising 1.10, 10 and 33% segregated R fibers. After desizing, the "thermal behavior" is measured and the synergistic effect calculated.

Table 4 % R fibers thermal behavior synergistic yarn type (Para-aramid) (MJ / dtex) effect 0% 1.3 negative 100% meta-aramid 1% 54.6 221% Meta / para-aramid 2% 36.1 112% MetaVParaaramid 10% 33.0 94% Meta / para-aramid 33% 27.5 62% MetaVParaaramid 100% 17.0 0% 100% para-aramid

It should be noted that the meta / para-aramid yarns in Table 4 are S yarns.

The increased synergistic effect due to the low percentage (1 and 2%) of R-fibers whose probability of occurrence is ensured by segregation is evident. The numbers of Table 4 are shown in Curve C in FIG.

Although modacrylic fibers have an LOI value greater than 26.5 and thus do not continue to burn when the source of ignition is removed, the protective effect as a shielding or protective layer in flame retardant clothing is rather low, since tissue deterioration occurs very rapidly.

EinS yarn according to the present invention is comprised of 98% modacrylic fibers having a fiber length of 40 mm (1.6 Z oII) and 1.7 dtex (1.5 dpf) (VELICREN FRS modacrylic fibers) and 2% in the core of the yarn, deliberately segregated para-aramid fibers. R-Fasem (Polyparaphenylenteräphthalamid) to 40mm (1.6 inches) fiber length and 2.2 dTex (2.0dpf) (Twaron fiber) produced. The spinning of the yarns was done on a DREF friction spinning machine using the sliver roving mating system and using a sliver and a non-twisted roving, as discussed above. The yarns having a count of 49 Tex become a plain weave fabric 21 χ 21 fibers / cm processed. The same fabrics are made of 100% VELICREN FRS fibers and 100% TWARON fibers.

The numbers of the "thermal behavior" are measured and the synergistic effect calculated, as shown in Table 5.

Table 5

yarn type

100% para-aramid

100% Modakrylf.

98% Modakrylf.

% R fibers

100% 0% 2%

Heat retardant (mJ / dTex) 21.8 0.2 25.2 Synergistic effect 0% negative

15%

Although the synergistic effect with respect to the fabric mentioned examples with meta-amides, the "Wärmeverha R-fibers is produced by the inventive method w heat behavior of 98/2% -S-yarn with Modakrylfasern is se

Table I.

As already mentioned above, the improved "heat-dissolving glue theory for Α-fibers (same organic synthetic FF in US Patent 4198494. The necessary occurrence of producing fabrics without fusible FR fibers, but rr is investigated.

On a DREF friction spinning machine, the following FR yarns are 100% viscose fr

S10 yarn 90% viscose FR and 10% KELVAR (R fiber)

S2 yarn 98% viscose fr and 2% KELVAR (R-fiber)

These yarns, in turn, are tested for thermal behavior each time to a fabric of 1 , and the results are not as conspicuous in the valley of 100% paraaramid as in the above n "of fabric made from modacrylic s-garams at only 2%. de, better than the "thermal behavior" of 100% R-fibers. The ar is equal to that of the 95/5% -l-yarn of metaaramide in the

asern be explained in the present invention), like that of the fusible organic FR-fibers is inorganic FR-fibers in combination with ^R-fibers: not n "at lower percentages of R-fibers according to the

ame made to 49 Tex:

x 21 threads / cm woven after desizing. It was shown ile 6.

Table 6

yarn type

Ring spun yarn FR yarn S10-Gam S2-Gam

% R fibers Wärmeverhalter (MJ / dtex) 100 17.0 0 4.5 10 88.6 2 13.1

synergistic

Effect,%

negative

421%

negative

As you can see, the 2% deliberately segregated R-Fe are little to achieve a sufficiently increased synergistic effect, even if the improvement of the 'thermal behavior' compared to the sum of the "heat behavior shares" the only If the 10% R-fibers used Be a strong verbes presence of fusible organic FR fibers is not achieved.

Preferably, according to the invention, the percent weight of R fibers, if only in combination with non-organic ones, as mentioned above, is a significant disadvantage of many Vc heat shrinkage and rapid breakup. In the ot proposed, which is often used as a thermal protection behavior test (TPP-made fabrics exposed to fabrics), the time to rupture knife in combination with a non-organic FR fiber is equalized to the 100% thermal behavior. R fiber to Dn 4.5 m J / dTex to 13.1 mJ / dTex has a synergistic effect ien components (4.6mJ / dTex).

synergistic effect clearly. Therefore, this is necessary because it can have an increased synergistic effect

3r deliberately, positively or otherwise intended segregated VFasern be used, not less than 3%, chläge for flame retardant materials in the high US Patent mentioned is a "fabric bursting test" 3St) is called He was at the invention ärmefluß of 8.4mJ / cm ² s over the standardized 10s if this does not happen, these are indicated with more than 10s.

Table 7 shows the tearing tests for the intimate tissues according to Table 1. (Aufreißtest) Table 7 3S überiOS Composition TPP test überiOS (% FR /% R) überiOS 100/0 über10S 95/5 over 10 s 90/10 80/20 67/33 0/100

The invention according to the invention with 10% segregated R-fibers hergestei tearing of more than 10 seconds (about 10S) on.

3 Tissue listed in Table 2 also has

Table 8 % R fibers in the TPP test Used yarns tissue (Aufreißtest) 0.0 4s AlleFR game 4.8 over 10 s (some flames) 1S + 4FR Game 8.0 überiOs 1 S + 2FR yarns 24.0 übeMOs AllS yarns

In the fabric with 4.8% R-fibers, some flames were observed at the top of the tissue sample, tearing occurred

However not.

Even the meta-yarn fabric from S yarns with only 1 and 2% segregated R-fibers as listed in Table 4 and the modacrylic fabric with only 2% R-fibers from Table 5 did not rupture within 5 seconds.

The tearing properties of fabric of viscose FR fibers with 2% and 10% Segregated R fibers, as listed in Table 6, are reported in Table 9.

Table 9

Used yarns % R fibers R-fibers - TPP test thermal behavior in the tissue % - (Aufreißtest) (MJ / dtex) FR Yarn 0 - 1s S10 yarn 10 0 - überiOs 1.1 S2-yarn 2 überiOs Below are examples of "heat behavior" 0 - 0.9 Threads / cm. - materials 0 - 1.7 - meta-aramid 1 - 54.6 CONEX 0 'of tissue. All fabrics consist of yarns of 49 χ 49 Tex and about 21x21 0.6 meta-aramid APYEIL 0 I / S-Game 0.4 80/20% APYEIL / 4 31.8 Viscose FR 99% meta-aramid 10 -_ 32.9 APYEIL 10 88.6 PolyimidP84 - 50/50% P 84 / Viscose FR I 96 4PolyimidP84 70/20% APYEIL / S Viscose FR - 90% viscose FR Percentage synergistic effect To the pictures 1 and 2 I Percentage of R-fibers Fabric sample S Intimately mixed Quartz tube fiber segregation Weight S tissue segregation Contact height S To the pictures 3 and 4 Percentage synergistic effect tissue sample Percentage R-fibers quartz tube Intimate blended mass Fiber segregating contact height Fabric segragating

Claims (24)

A process for producing a flame resistant combination of at least two flame resistant staple fiber components in sliver, roving, single or multiple yarn, woven or knitted fabric form, characterized in that one of the components intentionally, positively or otherwise intended over the other component or the other components of the combination is kept separate. 2. A process for the preparation of a flame-resistant combination of at least two flame-resistant staple fiber components according to claim 1, in the form of a woven or knitted fabric, characterized in that the "thermal behavior properties" are synergistic in relation to the corresponding properties of the individual components. 3. The method according to claim 1, characterized in that the components are joined together such that one of the components in the form of a roving and the other components or components in the form of a sliver. 4. The method according to claim 3, characterized in that the Vorgarnkomponente is used without rotation. 5. The method of claim 1,3 or 4, characterized in that the components are joined together such that the combination contains in yarn form the one component concentrated in the core of the yarn. 6. The method according to claim 1, characterized in that the components are joined together such that the combination includes in Mehrfachgarnform at least one twist with the one component. 7. The method according to claim 1, characterized in that the components are joined together such that the combination includes in Mehrfachgarnform at least one twist, which was prepared according to claims 3,4 or 5. 8. The method according to claim 2, characterized in that the components are joined together so that the combination in the form of a fabric in the warp and the weft direction of the fabric includes flame-resistant yarns having the one component, the flame-resistant game around a Distance are separated from each other, which has a maximum value of twenty times the tissue thickness. 9. The method according to claim, characterized in that the components are joined together so that the combination in the form of a fabric in the warp and the weft direction of the fabric includes flame-resistant yarns, which consist of a combination of at least two components, which after a of claims 3 to 7, wherein the flame resistant yarns are separated by a distance having a maximum value twenty times the fabric thickness. 10. The method according to any one of claims 1 to 9, characterized in that the one component has a "thermal behavior" with a maximum of 15mJ / dTex. 11. The method according to any one of claims 1 to 10, characterized in that are used for the one component Polyparaphenylenterephthalamid- and / or formophenol and / or Polybenzimidazol- and / or Kohlenstoffasem. 12. The method according to any one of claims 1 to 11, characterized in that for the other component or components other natural and / or artificial materials which have been treated flame-retardant used. 13. The method according to claim 12, characterized in that for the other component or components WoII- and / or cotton and / or Viskoseseide- and / or protein staple fibers are used. 14. The method according to any one of claims 1 to 13, characterized in that for the other component or the other components artificial material which includes flame retardant additives is used. 15. The method according to claim 14, characterized in that for the other component or the other components Viskoseseide- and / or Diazetat- and / or triacetate and / or protein staple fibers are used. 16. The method according to any one of claims 1, 2, 3 and 5 to 15, characterized in that for the , other component or components, synthetic / organic materials including flame retardant additives. 17. The method according to any one of claims 1 to 15, characterized in that for the other component or components synthetic / organic materials which include flame retardant additives are used. 18. The method according to any one of claims 16 or 17, characterized in that polyester and / or polyamide and / or Polyakrylnitrilstapelfasern be used for the other component or components. 19. The method according to any one of claims 1, 2, 3 and 5 to 16 and 18, characterized in that for the other component or the other components inherently flame-resistant material is used. 20. The method according to any one of claims 1 to 18, characterized in that for the other component or the other components inherently flame-resistant material is used. 21. The method according to any one of claims 19 or 20, characterized in that modakryl and / or polyvinyl chloride and / or polyimide and / or polyamidoimide and / or polytetrafluoroethylene and / or Polymetapenylenisephthalamid- for the other component or components and / or crosslinked Polyakrylsäurefaserstoff is used. 22. The method according to any one of claims 12 or 15, characterized in that one component of a proportion of between 2 and 4 wt .-% is used to the total weight of the combination. A method according to any one of claims 16, 18, 19 or 21, characterized in that one component is used at a level between 0.5 and 40% by weight relative to the total weight of the combination. 24. The method according to any one of claims 17,18, 20 or 21, characterized in that of the one component, a proportion between 0.15 and 5Gew .-% is used to the total weight of the combination.