Object of the invention is a nonwoven fabric, a method of its preparation and its use.

A use of polypropylene-based nonwoven fabrics in typography as a carrier of information is known. However, these nonwoven fabrics are not environment-friendly. There are also known nonwoven fabrics that exhibit high fire resistance. Usually, production of such fabrics involves chemical substances of various types i.e. flame retardants that enhance their fire resistance. Nonwoven fabrics of that kind are used e.g. in fire-fighting and in branches of industry where a use of non-flammable protective clothing is necessary. From Polish Patent PL 191035, a method of manufacturing products in a form of polypropylene ribbons with added polyethylene, including antimonium trioxide and brominated hydrocarbon, preferably dibromobenzene, as flame retardants, is known.

From patents PL 100666 i PL 100667 slow-burning polyolefine blends for manufacturing fabrics, particularly polypropylene fabrics including - in addition to antimonium trioxide - organic halogenated compounds as flame retardants are known.

The invention relates to a viscose non-woven fabric, which does not include any other additives in the structure of non-woven fabric itself, and the applied flame retardants are ecological, i.e. they are environment-friendly, e.g. free from substances risky to environment. Object of the invention is a nonwoven fabric characterised in that, it consists of viscose fibres of 100% viscose content and optionally at least one flame retardant uniformly distributed on the nonwoven fabric at the amount from 5 to 35 wt. %, the flame retardant being selected from ecological flame retardants free from antimonium compounds and chlorinated compounds. The flame retardant is selected from a group consisting of ammonium sulfamate and phosphorus and nitrogen compounds.

Basis weight of the nonwoven fabric is from 30 to 250g/sq.m. The nonwoven fabric includes overprinted information, particularly advertising information. Object of the invention is also a method of manufacturing of non-flammable nonwoven fabric characterised in that, at least one ecological flame retardant free from antimonium compounds and chlorinated compounds at the amount from 5 to 35 wt. % (referred to the dried product) is applied, by means of spraying aqueous solution or by immersing into an aqueous solution, onto a nonwoven fabric consisting of 100% viscose fibres. Flame retardants selected from a group consisting of ammonium sulfamate and phosphor and nitrogen compounds are used.

An aqueous solution of flame retardants at concentration 8 to 20 wt. % is used.

Object of the invention is also a use of the above-mentioned nonwoven fabric in typography, as a carrier of overprinted patterns and/or information, particularly using offset process, digital techniques and silk-screen printing.

Object of the invention is also a use of the above-mentioned nonwoven fabric for manufacturing ecological products, particularly disposable goods, such as bedlinen, sleeping bags, protective clothing and tablecloths.

Object of the invention is also a use of the nonwoven fabric consisting of 100% viscose fibres as a carrier of information applied with offset process, digital techniques and silk-screen printing.

The new product makes it possible to eliminate or partially substitute nonbiodegradable plastics based on polypropylene and polyethylene with a viscose nonwoven fabric having similar physical properties. Thus, an ecological product is obtained for applications in typography as a carrier of all types of overprinted information e.g. small as well as large-dimension posters, information panels and billboards, and also for suitably shaped overprinted surfaces, e.g. for production of protective covers, tents and canopies acting as a carrier of e.g. advertising information. The novel viscose nonwoven fabric includes modern, ecological flame retardants, free from harmful substances. So, the nonwoven fabric may be used in various types of rooms, buildings and on buildings, where strict requirements have to be met because of occupational safety provisions. The fabrics may also serve as aesthetic overprinted casings of buildings during repairs and refurbishment.

The viscose nonwoven fabric of the invention in an optionally overprinted form is also suitable for manufacturing of all types of disposable products such as bedlinen, protective clothing, disposable packaging (protective covers), sleeping bags, tablecloths, etc. At present, flame retardants free from antimonium and chlorinated compounds are usually used, because of environmental protection.

Such flame retardants include natrium and potassium silicates, sulphates, e.g. ammonium sulphate, hydrates of aluminium oxide and aluminium oxide, phosphates, e.g. ammonium phosphate and polyphosphates, silicon poliacids, sulfamates, e.g. ammonium sulfamate, and sometimes borates and boric acid, although at present borium compounds are also eliminated. Particularly sulfamates, and phosphorus and nitrogen compounds, e.g. as salts, are used. These compounds can be optionally used as a mixture with cationic or nonionic surfactants, which improve adherence of flame retardants to a fibre surface.

The nonwoven fabric of the invention is made of textil raw material, which is 100% viscose fibre. A ready nonwoven fabric is free from other chemical substances like synthetic resins or latices. The fibre has a preparation, which makes it possible to process it on a production unit for forming fleece of nonwoven fabric. At the same time, because of the preparation no foam is formed when contacting with water, foaming being an effect undesirable at production of nonwoven fabrics by ,,spunlace" method.

Nonwoven viscose fabric has a wide basis weight range, i.e. 30-250 g/sq.m., which makes it possible to adjust the suitable thickness depending on typography needs and a purpose of overprinted nonwoven fabric surfaces. Through combining two products - a flame retardant and a viscose nonwoven fabric an ideal ecological product has been obtained, suitable to be used in printing machines, e.g. in digital machines of plotter-type and in offset machines. The resulting nonwoven fabric has very advantageous physical properties, which make it possible to eliminate similar materials made of plastics, e.g. polypropylene derivatives, which have worse flammability characteristics.

The nonwoven fabric is produced on a unit equipped with a system checking thickness/ basis weight, linked together by a feedback to a part forming fleece of nonwoven fabric. Such solution makes it possible to manufacture products exhibiting high and repeatable uniformity degree. These parameters determine high quality of the nonwoven fabric of the invention.

The present manufacturing process of the nonwoven fabric typical process solutions. A unit of feeding with fibre is an element responsible for supervising over proper raw material mixing, preliminary opening of fibres and preparation of fibres to carding process. A feeder and a carding machine are elements which are responsible for arrangement of uniform layer made of preliminary opened fibres and for carrying out carding process - complete opening of elementary fibres. The resulting fleece of nonwoven fabric is transferred to a cross-layerer, which is responsible for uniform arrangement of fleeces of nonwoven fabric, i.e. one on another. It makes it possible to adjust basis weight of nonwoven fabric. Furthermore, the device makes it possible to prepare fleece in such a way that in the final product a ratio of longitudinal strength to transverse strength is close to 1. It is particularly important for products which are to have technical applications. A compensating device ensures an introduction of a new step in the production cycle, i.e. smooth transferring of loose fleece from the layerer to a gill box. In the gill box, the fleece arranged by the layerer is stretched, which improves fleece structure and facilitates its further processing -joining by means of water needles. In water needling machine, non-joined fleece of the nonwoven fabric is transferred onto a conveyor, where a stream of water needles hits in it. A needling bar has 40 holes per 1 inch, through which water as water needles takes out under pressure up to 250 bars. Such directed water stream hits in the fleece of the nonwoven fabric and which becomes entangled while not destroying elementary fibres. A part of stream is reflected from the conveyor and crosses once more through the fleece entangling the fibres once again. Such process makes it possible to produce tight nonwoven fabric of very high purity, and the product does not include any additional chemical substances. The resulting product is wet, thus it has to be dried prior to packaging.

At this step, through a use of additional elements and modification of settings of the unit, it is possible to make texture (projection) on a wet nonwoven fabric. A particular spatial pattern on a nonwoven fabric surface is obtained. Drying a wet nonwoven fabric is effected in a dryer. Temperature has be adjusted to dry the nonwoven fabric while not overheating it.

The production line is equipped with a control device- thickness gauge (a meter of basis weight) of nonwoven fabric, which measures the product as it is produced. The result is recalculated into a signal which is transferred to a part that controls the unit operation.

In the final step, on a winding machine, the finished product is wound onto wounds. Then, it is possible to cut the nonwoven fabric into pieces of a definite width. The resulting non woven fabric has to be subject to a process of applying flame retardants. The process is carried out on a separate machine, which consists of a rewinder of nonwoven fabric, a device for applying the flame retardant, a dryer and a winding machine, on which finished non-flammable product is wound onto wounds. Flame retardant is preferably used in a form of a solution and is applied onto a surface of nonwoven fabric by spraying or immersing into a flame retardant bath. Upon drying, optionally the flame retardant may be again applied onto the nonwoven fabric by spraying. The non-flammable nonwoven fabric upon drying contains 5 to 35% or 5 to 25% or 5 to 15 wt. % flame retardant.

Example 1

A viscose nonwoven fabric obtained on the production line described above and consisting of fibres of 100% viscose content and free from other chemical additives of a basis weight of 150g/sq.m. upon drying was processed by applying aqueous solution of ammonium sulphamate. A flame retardant was applied by immersing the nonwoven fabric into an aqueous bath of ammonium sulphamate (10 wt. %.). Upon taking out the nonwoven fabric from the bath, an excess of solution was squeezed, and the nonwoven fabric was dried. A non-flammable nonwoven fabric of basis weight 165g/sq.m. was obtained.

Example 2

A viscose nonwoven fabric obtained on the production line described above and consisting of fibres of 100% viscose content and free from other chemical additives of a basis weight of 150 g/sq.m. upon drying was processed by applying an aqueous solution of ammonium phosphate. A flame retardant was applied by spraying the aqueous solution of ammonium phosphate (12 wt. %) onto the nonwoven fabric. Then, the nonwoven fabric was dried. A non-flammable nonwoven fabric of basis weight of 165 g/sq.m. was obtained.