Fibrous composition of matter

Abstract

An ignifuge or fire resistant intimate blend of fibres in the form of a composite yarn, a woven fabric made of such composite yarns, a non-woven fabric and textile articles obtained therefrom. The fibres are selected among glass fibres or ceramic fibres surrounded by at least two different kinds of fibres selected among synthetic and/or natural fibres. One of such two fibres has a melting point different from the other of the two fibres and both of the two fibres have melting points lower than the melting point of the glass or ceramic fibre wool and chlorovinyl fibres are among the preferred fibres surrounding the glass fibres. During the melting of the fibres surrounding the glass fibre, at least a partial disintegration thereof takes place and a carbonous deposit is formed on the glass fibres protecting them from heat and increasing heat resistant properties thereof.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a fibrous composition of matter, in particular for obtaining products with improved ignifuge characteristics. More particularly, the present invention relates to composite yarns having improved ignifuge characteristics, to fabrics obtained by said yarns and to non-woven fabrics having improved ignifuge characteristics, obtained from said fibrous composition of matter.

By the term ignifuge is generally meant a property of a fabric which does not permit the spreading or propagation of a flame (i.e. fire resistant). It is known that a fabric can be ignifuge because it is formed from ignifuge fibres or because it is formed from fibres which, after the fabric has been made, are processed, such as by impregnation treatment with suitable substances which confer said ignifuge property to the fabric.

The problem facing the experts in the art during the conceiving of a fabric having ignifuge properties, above all of a fabric to be employed for obtaining textile goods which is applicable to the clothing field and/or furnishing field, is represented by the necessity of conferring the fabric in the course of its manufacture, both with ignifuge characteristics, and with all those properties conventionally required from a fabric to be employed in the clothing field and/or furnishing field. It is known that, for some time, persons skilled in the art have been constantly in search of fibres that can satisfy and solve the problem or have been in search of substances for impregnating fabrics, which substances, while conferring to the fabrics the desired fire-resistant properties, would not diminish their other properties or characteristics. Thanks to said continual research, there are currently available ignifuge fabrics which appear satisfactory up to maximum temperature values in the order of 400.degree.-500.degree. C. On achieving or exceeding a temperature of the above order, in ignifuge fabrics currently available, there occurs a disadvantage caused by the fact that the fabric, both when obtained from ignifuge fibres or when impregnated with ignifuge substances, becomes easily perforated or is heat-conductive as, for example, in the case of glass fibres.

In fact in fire accidents it is not only important to prevent the spreading of fire over the clothes, but also to prevent eccessive heat to reach the body of the user.

SUMMARY OF THE INVENTION

The main object of the present invention is to produce a flameproof, heat-insulating composition of matter which can be processed into yarns, textiles, and non-woven fabrics suitable for application in the garment and furnishing field as well as for industrial applications, and whose flameproof properties are such as not only to prevent the spreading of the flame, but also to resist perforation by a flame at temperatures higher than 400.degree.-500.degree. C which is the maximum temperature at which flameproof fabrics at present commercially available can resist.

It is a further object of this invention to produce a fibrous composition of matter with properties of the above-mentioned type that can easily be formed from materials which are normally commercially available, employing production processes of a known type so as to be advantageous also from the strictly economic point of view.

These and still further objects, which will better appear from the following, are achieved by a fibrous composition of matter comprising a blend of glass fibres and of at least two fibres selected from the group consisting of synthetic fibres, natural fibres and blends thereof the synthetic and natural fibres having a melting point below the melting point of said glass fibres and which, when melting, form on said glass fibres a substantially carbonous residue.

The term "melting point" as used in this specification should be intended in the sense of a melting process which involves at least a partial disintegration of the molecular structure of the fibre and in which the boundaries between the pure melting process and the pure disintegration might not be exactly defined.

In one of its aspects, the present invention relates to a composite yarn, comprising a glass-fibre core and a coating for said core formed from at least two fibres selected from the group consisting of synthetic fibres, natural fibres and blends thereof having melting points which differ from each other and are below the melting point of said glass fibres and which, when melting, form on said core a substantially carbonous residue, said melting involving at least a partial decomposition.

By the term "glass fibres," as used in this specification and in the accompanying claims, are meant common glass fibres, "beta" glass fibres, ceramic fibres and the like fibres. "Beta" glass fibres appear to be of particular advantage for the applications of this invention. "Beta" fibres are manufactured by Owens-Corning Fiberglas Corporation of U.S.A., but under the term "Beta" glass fibres as used in this specification glas fibres having singularly a diameter of less than 5 microns should be intended. Synthetic and/or natural fibres having disintegrative melting points lower than that of said glass fibres, useful in the present invention, comprise, woollen fibres, artificial proteic fibres, naturalsilk fibres, chlorovinyl fibres, modacrylic fibres, acrylonitrile fibres, polyester fibres, polyamide fibres, cellulose fibres, preventively treated with fire-resistant substances and their blends.

Particularly advantageous, in applications of this invention are woolen fibres and chlorovinyl fibres, in combination with said glass fibres and in particular with beta glass fibres.

Further characteristics and advantages of the invention will better appear from the description of examples of the fibrous composition of matter, of yarns and non-woven fabrics obtained therefrom, which are given hereinafter as indicative and not limitative examples.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

EXAMPLE 1

The obtaining of a composite yarn took place by employing, as the core of said yarn, beta glass fibres manufactured by Owens-Corning Fiberglas Corporation and a coating formed from a blend of wool and vinyl fibres, and more precisely a polychlorovinyl fibre, commercially known under the trademark of "Leavin" manufactured by the Italian Company Chatillon S.p.A. of Milan, Italy. Said polychlorovinyl fibre melts, without flame, at a temperature of about 250.degree. C while wool notoriously burns slowly, melting at a temperature of over 300.degree. C. Beta glass, which forms the thread-core of the composite yarn according to the present invention, has a melting point of about 1,000.degree. C.

The weight proportions of the components of the yarn were as follows: 100 parts by weight of Td 100 Beta fibre glass, 60 parts by weight of 66.sup.s wool and 40 parts by weight of polychlorovinyl fibre "Leavin" of 3 deniers. First a roving of wool and Leavin fibres was made with the indicated proportions in conventional manner and the roving and the fiber glass thread were joined by the conventional "core spun" technique. A composite yarn has been obtained in which a core of fibre glass was completely surrounded by fibres of wool and Leavin forming a coating.

The composite yarn thus obtained was exposed to a Bunsen flame of about 800.degree. C. First the melting of the Leavin fibre was observed, which formed a deposite on the other fibres retarding the heat action thereon. Subsequently the wool fibres begun to melt and decompose.

It was observed that the melting residue of Leavin fibres and the melting residue of wool fibres mixed and formed a carbonous residue which made a protective and insulating deposite on the glass fibres. The yarn showed a surprising heat and fire resistance. It is believed that these surprising fire and heat resisting properties are aided by the following mechanism.

Initially, the decomposition of the polychlorovinyl fibre takes place with the development of acidic gas and a deposit of said fibre on other fibres with which it is intimately mixed. At a given point, the wool fibres which have an inflamability point of about 600.degree. C begin to melt with the development of basic gas. The two gases developing from the melting of the polychlorovinyl and wool fibres, partly neutralize each other, thus preventing the wool from burning, due to lack of oxygen; the amalgam formed from the chlorovinyl residues and of the carbon residues originating from the wool are depositated on the beta glass fibre (the core of the composite yarn). This glass fibre is thermically protected by such residues deposited on it, resisting up to over 900.degree. C before initiating the melting process.

The composite yarn according to the invention was woven, forming textile goods having, in addition to the above mentioned surprising ignifuge characteristics, all those properties normally required for clothing and furnishings. The tests carried out, showed that, when subjected to the action of fire the heat insulating properties of the fabric remarkably increased.

EXAMPLE 2

A composite yarn was obtained according to the indications of example 1, in which however the wool fibre was substituted by an artificial proteic fibre, for example a caseine F fibre known commercially under the trademark "Merinova," manufactured by the Italian Company SNIA VISCOSA. The composite yarn thus obtained, when subjected to the action of a flame, resisted up to temperatures in the order of 800.degree. C.

EXAMPLE 3

A composite yarn was obtained according to indications of example 1, substituting the wool with natural silk. In this case, when subjected to a flame, the yarn resisted up to a temperature in the order of 700.degree. C.

EXAMPLE 4

Following the indications of example 1, a composite yarn was obtained by employing, as the core of said yarn, beta glass fibres, and an intimate bend of modacrylic fibre and wool fibre as a coating. This composite yarn, when subjected to the action of the flame, resisted up to temperatures in the order of 700.degree.-750.degree. C.

EXAMPLE 5

The procedure of Example 4 was repeated, substituting the wool fibres with artificial proteic fibres and/or with silk fibres. The composite yarn obtained had fire-resistant characteristics comparable with those of the yarn of Example 4.

EXAMPLE 6

The procedure of obtaining a yarn according to Example 4 was followed, wherein however the coating of the beta glass fibre was obtained by first forming a thread from the rovings of acrylonitrilic and polyester fibres and then jointing together such thread with the thread of glass fibre by a conventional end-to-end technique. The composite yarns obtained according to this example, subjected to the action of the flame, resisted up to a temperature in the order of 550.degree.-600.degree. C.

EXAMPLE 7

The procedure for obtaining a composite yarn according to example 1 was followed, substituting the chlorovinyl fibre with polyester. When subjected to the flame, the composite yarn resisted temperatures in the order of 550.degree.-600.degree. C.

EXAMPLE 8

The procedure as described in Example 1 was followed with the exception that the polychlorovinyl fibre was substituted by 66 polyamide fibre, while the wool was substituted each time by other artificial proteic fibres or by natural silk. In each case composite yarns were always obtained which resisted high temperatures, comparable with those against which the yarn obtained by Example 1 resisted.

EXAMPLE 9-9A

The procedure according to that described in examples 1-8 was followed, with the exception that a beta glass fibre was substituted, the first time, with a common glass thread, and the second time with a ceramic thread, thus obtaining two composite yarns which resisted a temperature in the order of 600.degree.-650.degree. C before melting, which means that they had altogether surprising ignifuge characteristics compared with the fire-resistant characteristics of yarns up to now known.

The yarns obtained according to the previous examples, were woven and shaped into textile goods having, in addition to the above-mentioned surprising ignifuge and insulating characteristics, all those properties normally required from fabrics which are applicable to the fields of clothing industry, furnishings and other known industrial applications.

It has been found that the same fibres which form the composite yarn in examples 1-9-9A, could advantageously be used in obtaining fabrics of the so-called non-woven type or felted fabrics, having most marked ignifuge characteristics and practically comparable with those of the composite yarn as in the above examples, and of fabrics obtained from said composite yarn.

The non-woven fabric of the above-mentioned type is suitable for numerous applications among which the most remarkable ones are the obtaining of linings or stuffings, wall-to-wall carpets of the "moquette" type, so-called "pressed" articles, on prior impregnation of the non-woven fabric, with appropriate bending or adhesive agents as additives; thses articles had the same surprising and highly desired ignifuge and increased insulating characteristics under the action of fire.

These non-woven fabrics can be manufactured by intimately blending a first fibre selected from the group comprising beta glass fibres, common glass fibres, ceramic fibres and silicious fibres, with at least two other fibres which are selected from natural and/or synthetic fibres, these natural and/or synthetic fibres having different melting points, and below the melting point of said first fibre, and forming, on melting, a substantially carbonaceous residue on said first fibre.

Advantageously, said second fibres are selected from wool fibres, artificial proteic fibres, natural silk fibres, chlorovinyl fibres, modacrylic fibres, acrylonitrilic fibres, polyester fibres, polyamide fibres, and their blends.

The following are some examples of non-woven fabrics obtained with fibres of the above-mentioned type.

EXAMPLE 10

10 kg. of glass tuft or flock and 10 kg. of wool tuft or flock and 10 kg. of polychlorovinyl tuft were thoroughly mixed, and a non-woven fabric of the felted type was obtained therefrom by conventional techniques. Repeated and strictly controlled tests, showed very high ignifuge properties, currently unavailable in the known non-woven fabrics, and even higher than the ignifuge properties of the single fibres composing the fabric thus obtained. This was explained by a cooperative ignifuge action of surface and near to surface layers of the fabric.

With the non-woven fabric of this example, paddings or stuffings in general were easily obtained as for instance paddings for furnishings, motor-car seats, to the obtaining of covering elements such as for instance wall-to-wall carpets and the like, which all had the same desired fire-resistant characteristics.

On prior impregnation with appropriate adhesive additives, as for example chlorovinyl resins and the like resins, and subsequent moulding, with the non-woven fabric of Example 1, shaped "pressed" articles, having ample and different applications and the desired ignifuge characteristics, were obtained.

EXAMPLE 11

A non-woven felted-type fabric was obtained in a conventional manner by intimately mixing 10 kg. of ceramic fibre, 10 kg. of modacrylic fibre and 10 kg. of wool or other artificial proteic fibres or silk. In all cases, the non-woven fabric thus obtained when subjected to the effect of a flame, resisted very high temperatures in the order of 700.degree.C before the melting process of the internal layers of the fabric started. Similarly, as already mentioned in Example 10, this non-woven fabric was used to obtain articles such as, for example, paddings or stuffings, articles for covering and the like, all having high ignifuge characteristics.

In other embodiments of the non-woven fabric of this invention, different combinations of glass fibres, ceramic fibres, beta glass fibres in an intimate blend with at least two other fibres of which one was selected from the group of woollen fibres, artificial proteic fibres, natural silk fibres and the other one was selected from the group of chlorovinyl, modacrylic, acrylonitrilic, polyester, polyamide and the like fibres or their blends, were used. All the non-woven fabrics obtained from these combinations had surprising ignifuge characteristics and were easily processable for obtaining textile goods, such as paddings in general, covering articles, ropes and the like. On prior impregnation with adhesive substances of the synthetic resins type, compatible with the employed synthetic fibres and with simple moulding operations by pressing, it was possible to obtain shaped or pressed articles in different forms and of different even considerable dimensions, all having the desired ignifuge characteristics.

In a particular application of the non-woven fabric according to the invention, a fabric formed substantially of three adjacent layers was obtained in a single piece. Each layer was formed of three types of fibres, selected from the above mentioned groups, each layer having, with respect to the other adjacent layers, either the same quantitative combination of the three fibre types of different combinations, with one fibre type prevailing with respect to the remaining two.

Yarns obtained as above described but inwhich instead of Leavin fibres the following vinyl fibres were used.

Fibravyl manufactured by the French Company Soc. Rhovyl

Clevyl T manufactured by the French Company Soc. Rhovyl

Rhovyl manufactured by the French Company Soc. Rhovyl

Thermovyl manufactured by the French Company Soc. Rhovyl

Vinyon manufactured by the U.S.A. Union Carbide Corp.

showed similar surprising ignifuge characteristics.

Claims

I claim:

1. A composite yarn which exhibits fire resistant properties due to thermal decomposition, said yarn comprising a glass-fiber core, a carbonizable coating for said core consisting of a blend of a natural animal fiber with a synthetic fiber, said coating exhibiting thermal decomposition, upon being subjected to high temperatures, and forming a substantially carbonaceous residue rendering the yarn fire resistant.

2. The composite yarn of claim 1, wherein said glass fiber is selected from the group consisting of beta glass fibers, common glass fibers, ceramic fibers and mixtures thereof.

3. The composite yarn of claim 1, wherein said natural fiber is selected from the group consisting of wool fibers, silk fibers, artificial proteic fibers and mixtures thereof.

4. The composite yarn of claim 1, wherein said synthetic fiber is selected from the group consisting of polyvinylchloride fibers, polyamide fibers, modacrylic fibers, polyester fibers, polyacrylonitrilic fibers and mixtures thereof.

5. The composite yarn of claim 1, wherein said glass fiber core consists of a filament of beta glass and said coating consists of an intimate blend of polyvinylchloride fibers and wool fibers.

6. The composite yarn of claim 5, wherein said glass filament is wrapped by said polyvinylchloride fibers and wool fibers which form a tube-like coating for said filament.

7. The composite yarn of claim 5, wherein the weight ratio glass fibers: polyvinylchloride fibers: wool fibers is approximately 100:40:60.

8. A fabric made of composite yarn of claim 1.