Mixed yarns made of activated carbon and fabrics manufactured therefrom.

Aktivkohle.wird particular as granules for various purposes, such as plants for reclamation of solvent vapors, filter systems for decoloring liquids, for odor filters in hoods, medical applications, gas mask filters, NBC protective suits etc..

Recently come for surface filter woven or nonwoven fabrics of activated carbon on the market. In the form of fibers, activated carbon is particularly effective due to the low ratio of surface area to volume, which improves the accessibility of the pores. These woven or nonwoven fabrics of activated carbon are produced by carbonizing woven or nonwoven fabrics made of carbonaceous materials and subsequent activation with steam, but never by processing individual carbon fibers. The advantages of high adsorptive capacity of such surface filter is, however, compared to the disadvantage of the very limited mechanical strength. Therefore, they may be suitable for stationary installations, for example, but not for protective suits against chemical warfare agents.

The invention has for its object, the advantages of the activated carbon fiber with the mechanical strength of a fabric of non-carbonized fibers to a ver. This was accomplished by a mixed yarn, which consists of 5o to 75, in particular 2o to 4o weight percent of activated carbon staple fibers and the balance of textile staple fibers, as well as fabrics, which are made from this yarn.

The yarn according to the invention is prepared by one cuts a per se known cable of activated carbon monofilaments into staple fibers, mixed gently with textile staple fibers and spinning. The activated carbon staple fibers have advantageously a length of 1 to 1o cm. In order for these staple fibers remain not break when mixed with the other used to prepare the mixed yarn textile fibers but get as in the predetermined length, the active carbon staple fibers with the other staple fibers of comparable length are suitably mixed in a carrier liquid, in particular water or an aqueous liquid , Best left to the active carbon staple fibers after cutting of a cable, which is usually from 10,000 to several 1₀₀,₀₀₀ Monofilament is, fall into a bath, in the same time the textile individual fibers are added. In the liquid medium then additional measures for mixing the staple fibers can be adopted, in many cases, but a sufficient mixing of the various staple fibers in the removal of the carrier liquid and the subsequent spinning is already reached to the mixed yarn.

The textile fibers which are to be inventively spun with the active carbon staple fibers into blended yarns, may be to a wide variety of natural or synthetic, organic or inorganic fibers, such as cotton, wool, silk, polyester, polyamide, or aramid act glass fibers or other mineral fibers. Polyamide, polyester or aramid fibers are preferred for the preparation of the mixed yarns of the invention. The textile staple fibers blended fabrics may be made of flame-resistant synthetic polymers or be made flame-resistant.

The activated carbon staple fibers typically have a denier of o, 5-2₀, In particular 1 to 5 dtex. The titer of textile fibers moves generally in the same range. The mixture of active carbon staple fibers with the textile staple fiber is spun in a known manner to mixed yarns and this can in turn interweave well. Here, the yarn containing the active carbon staple fiber can be used depending on the intended use of the tissue either in the shot, only in the chain or in both warp and weft. If a purely textile yarn is used for the warp or weft need this not to be made of the same material as the staple fibers of the composite yarn, but can be adapted to the particular use of the fabric.

This fabric of the invention can develop their full filter effect of the activated carbon staple fibers containing yarn, the fabric advantageously have an air permeability of 1o to. 1₀₀₀, Especially 15o to 3oo 1 / min 1oo cm² at 1 mbar vacuum. The air permeability can be achieved by weaving a loose yarn, which can be defeated also tightly then or reach through an open fabric.

Regardless of the air permeability, the fabric should have a tenacity of 1oo to 2₀,₀₀₀, In particular to 2oo 2.ooo Newton / possess 5 cm, which can be achieved both by choosing sufficiently tear-resistant staple fibers of the yarn as well as by the Mitverweben very tear-resistant yarns.

The basis weight of the mixed fabric can range from 5o to 1.5₀₀ g / m² rich, for most applications is a basis weight of 2oo to 4oo g / m² prefers.

Overall, fabrics of this invention are characterized by excellent textile properties, good strength and adsorption activity, which, based on the amount of active carbon fiber fabrics of pure activated carbon fibers was not inferior.

The fabric of the invention from the active carbon staple fibers containing mixed yarns are preferably used for surface filter. Here they are, because of their better mechanical properties more versatile and resilient than the surface filters manufactured by carbonizing fabrics. The good textile properties and strengths of the inventions gsgemäßen tissue also allow their use for the production of protective suits, especially those for commercial or military purposes, ie for protection against chemicals or chemical warfare agents.

example

Pre oxidized polyacrylonitrile fibers of 1.5 dtex were carbonized in a known manner as a cable with 32o.ooo individual filaments and subsequently activated in a suitable for this oven with steam. In order for a cable of activated carbon fibers with good mechanical properties and a BET surface area was measured with nitrogen, of 35o m²/ G.

Similarly, cellulose fibers were carbonized and activated. Their BET surface area, measured with nitrogen, was 1.loo m²/G. Although the high level of activity at the expense of mechanical strength, but allows nevertheless the further processing described below for yarn or the subsequent weaving.

Furthermore, carbon fibers produced from 18 dtex were activated with steam from pitch. The measured nitrogen BET surface area was 8₀₀ m²/ G with sufficient mechanical strength.

For the cables of the activated carbon fibers staple fibers were cut by 3 cm in length. One part by weight of activated carbon staple fibers dtex was mixed in water with 2 parts by weight of polyester staple fiber of likewise 3 cm length and 1 and then spun. It mixed yarns were obtained dtex of about 7o and from this fabric having a basis weight of about 28o g / m² prepared with mechanical properties similar to those of similar polyester blend with wool or viscose staple match. The activity of the activated carbon fibers was not affected by the spinning of the yarn and weaving for blended fabrics.