"PROTECTIVE TEXTILE AGAINST THE ACTION OF MELTED

MATERIALS" DESCRIPTION

The present invention relates to a protective textile against the action of melted materials.

The present invention arises from the requirement of protecting the operators of different industrial fields, such as carpentries, shipbuilding industry, blast furnaces, metal weldings of different types, from the splashes of melted materials, particularly from the melting of metals, asphalts, and preventing possible accidents due to the contact with these materials . There are clothes manufactured for this purpose on the market, such as for example aprons, gloves, jackets and the like made of leather with a remarkable thickness, which are heavy and difficult to wear and poorly comfortable, however capable of protecting from the action of the melted material, or items carried out with proper, light, more comfortable fabrics but which often do not protect adequately.

The materials used in the known art for the production of such protective items generally consist of aramidic fibers, specifically para-aramidic and meta-aramidic fibers, often in combination with other fibers, such

as wool or flame retardant viscoses. In particular, these latter act as sacrificial fibers, by absorbing the heat released by the melted metal during its cooling, so as to allow the aramidic fibers to play the real protective action.

The Applicant has found that the materials used for the protection from melted materials of the known art can be improved. In fact, the commonly used fabrics show a protection deficiency with respect to metals or high-melting alloys, such as for example iron, which has a melting temperature of 153β°C or steel, which melts between 115O ⁰ C and 1536°C depending on the carbon percentage contained therein. In particular, the articles of clothing of the known art do not ensure an adequate protection above all with respect to melted aluminium. Aluminium has a melting temperature of 660 ⁰ C and a high heat capacity, or it is able to release a lot of heat by slightly varying its temperature. During the initial moments of the cooling process, in fact, aluminium undergoes a passivation phenomenon, i.e. it covers itself with an oxide layer which drastically slows heat exchanges with the surrounding environment and therefore the cooling itself. The combined action of the melting temperature, even

if not particularly high, and above all of the heat capacity, which extends the cooling time thereof, causes aluminium to impair the effect of the sacrificial fibers: aramidic fibers are therefore easily at- tacked, melted and the protective action of the fabric is lost.

In this context, the main technical task of the present invention is to provide a protective textile which overcomes the above mentioned drawbacks of the known art.

In particular, an aim of the present invention is to provide a protective textile capable of withstanding the action of any melted material, and particularly any melted metal, in order to protect the operator. A further aim of the present invention is to provide a textile which allows to produce protective garments easy to wear, light and which are comfortable for the user. The stated technical task and the specified aims are substantially attained by a protective textile against the action of melted materials, including the technical features stated in one or more of the appended claims . Further features and advantages of the present inven- tion will better result evident from the indicative,

and therefore not limitative, description of a preferred but not exclusive embodiment of a protective textile, as it is shown in the drawings, wherein:

- figure 1 is a sectional representation of a protec- tive textile portion according to the present invention, in a first embodiment;

- figure 2 is a section of the protective textile according to the present invention, in an embodiment variation shown in figure 1; - figure 3 is a section of the protective textile according to the present invention, in a second embodiment;

- figure 4 is a section of the protective textile according to the present invention, in a first embodi- ment variation shown in figure 3;

- figure 5 is a section of the protective textile according to the present invention, in a second embodiment variation shown in figure 3;

- figure 6 is a section of the protective textile ac- cording to the present invention, in a third embodiment;

- figure 7 is a section of the protective textile according to the present invention, in a fourth embodiment; - figure 8 is a section of the protective textile ac-

cording to the present invention, in an embodiment variation shown in figure 7;

- figure 9 diagrammatically represents a section of the textile of figure 2, following to the action of the melted materials;

- figure 10 diagrammatically represents a section of the textile of figure 8, following to the action of the melted materials;

- figure 11 represents an image of the textile sur- face, according to the embodiment of figure 3, subjected to the action of splashes of melted iron;

- figure 12 represents an image of the lower surface of the textile of figure 11;

- figure 13 represents an image of the textile sur- face, according to the embodiment of figure 3, subjected to the action of splashes of melted stainless steel;

- figure 14 represents an image of the lower surface of the textile of figure 13; - figure 15 represents an image of the textile surface, according to the embodiment of figure 3, subjected to the action of splashes of melted aluminium;

- figure 16 represents an image of the lower surface of the textile of figure 15; - figure 17 represents an image of the textile sur-

face, according to the embodiment of figure 4, subjected to the action of splashes of melted iron/

- figure 18 represents an image of the lower surface of the textile of figure 17; - figure 19 represents an image of the textile surface, according to the embodiment of figure 4, subjected to the action of splashes of melted stainless steel;

- figure 20 represents an image of the lower surface of the textile of figure 19;

- figure 21 represents an image of the textile surface, according to the embodiment of figure 4, subjected to the action of splashes of melted aluminum;

- figure 22 represents an image of the lower surface of the textile of figure 21;

- figure 23 represents an image of the textile surface, according to the embodiment of figure 6, subjected to the action of splashes of melted aluminum;

- figure 24 represents an image of the upper surface of the first textile layer, according to the embodiment of figure 8, subjected to the action of splashes of melted iron;

- figure 25 represents an image of the lower surface of the first textile layer, according to the embodi- ment of figure 8, following to the action of splashes

of melted iron on the upper surface of the first layer;

- figure 26 represents an image of the lower surface of the second textile layer, according to the embodi- ment of figure 8, following to the action of splashes of melted iron on the upper surface of the first layer;

- figure 27 represents an image of the lower surface of the second textile layer, according to the embodi- ment of figure 8, following to the action of splashes of melted iron on the upper surface of the first layer;

- figure 28 represents an image of the upper surface of the first textile layer, according to the embodi- ment of figure 8, subjected to the action of splashes of melted aluminum;

- figure 29 represents an image of the lower surface of the first textile layer, according to the embodiment of figure 8, following to the action of splashes of melted aluminum on the upper surface of the first layer;

- figure 30 represents an image of the upper surface of the second textile layer, according to the embodiment of figure 8, following to the action of splashes of melted aluminum on the upper surface of the first

layer;

- figure 31 represents an image of the lower surface of the second textile layer, according to the embodiment of figure 8, following to the action of splashes of melted aluminum on the upper surface of the first layer.

With reference to the enclosed figures, a protective textile according to the present invention has been generally identified by 1. The protective textile 1 includes at least an orthogonal fabric layer 2, having a weave carried out with a first series of yarns having a decomposition temperature higher than 400 ⁰ C, preferably higher than 45O ⁰ C. Preferably, the decomposition temperature is lower than 800 ⁰ C.

Within the scope of the present description and of the attached claims, with "decomposition temperature" it is meant the temperature at which the material forming the yarn starts to modify its chemical-physical char- acteristics because of the rising of processes of melting and/or chemical decomposition.

Preferably, these yarns include aramidic fibers, in particular para-aramidic or meta-aramidic fibers . Generally, this first series of yarns has the function of sacrificial material, or it is degraded by the heat

of the melted materials with which they come into contact so as to accelerate the cooling of the molten drops of materials.

The weave further includes a second series of quartz yarns, having a silicon percentage at least of 90%, preferably between 95% and 100%, still more preferably between 99% and 100%.

The quartz fibers, as well as the aramidic fibers, can be arranged either in the warp or in the weft, or in both the weaving directions. In this latter case, it is possible to arrange the quartz fibers side by side or twisted together with the aramidic ones in the same weft or warp yarn, or in an alternating way by providing, in the weft and/or warp, a quartz yarn alternated with an aramidic one.

According to a preferred embodiment, said weave may further comprise preoxidized fibers, particularly pre- oxidized polyacrylonitrile (PAN) fibers. The latter are obtained starting from PAN fibers by oxidation re- action generally carried out at a temperature of 220- 260 ⁰ C for some hours. Such a reaction causes cycliza- tion of the -CN groups so as to form a fiber having high heat resistance. Such fibers are commercialized for instance with the tradename Panox® by SGL Carbon Group.

The preoxidized fibers can be subsequently subjected to a carbonization reaction at high temperatures (400- 1000 ⁰ C), generally in an inert atmosphere or under vacuum, so as to obtain the graphitic structure typi- cal of carbon fibers .

The preoxidized fibers may be laid in the warp and/or in the weft and may be laid side-by-side to the ara- midic fibers and/or to the quartz fibers, for example in an alternated sequence, or they may be associated to the aramidic fibers and/or to the quartz fibers during the spinning phase or during the twisting phase.

Preferably, the preoxidized fibers are spun or twisted in combination with the aramidic fibers, so as to in- crease the resistance to high temperatures of the latter.

According to a preferred embodiment, the fabric layer according to the present invention comprises a warp including yarns of aramidic fibers twisted with pre- oxidized fibers, and a weft including yarns of aramidic fibers twisted with preoxidized fibers, said yarns being alternated with quartz yarns. With reference to figure 1, a first embodiment of the protective textile 1 includes at least a fabric layer 2 whose warp 3 consists of 100% para-aramidic yarns,

having a fineness varying between 1500 and 1700 Dtex, preferably 1670 Dtex, and a density between 8 and 11 yarns/cm, preferably 9.5 yarns/cm. Said fibers do not have a melting temperature and start to decompose at about 500 ⁰ C.

The weft 4 consists, on the contrary, of a quartz fiber, having a melting temperature around HOO ⁰ C. More particularly, the weft consists of a two-stranded twisted quartz yarn, having a resulting fineness vary- ing between 15 and 45 Nm, preferably between 25 and 35 Nm, still more preferably 30 Nm, and a density varying between 8 and 15 yarns/cm, preferably 9 yarns/cm. The fabric resulting from the weft and warp interlacement above described has a weight varying between 200 and 250, preferably between 215 and 220 g/m ² .

Such a textile is highly resistant to the melting splashes of melted metals, particularly to the iron, steel or copper splashes. Advantageously, the protective textile 1 includes a plurality of fabric layers 2, according to the first embodiment above described, in quantities varying between two and six.

Preferably, there is a number of fabric layers 2 varying between two and four. The multilayer thus carried out is also able to resist to the passage of melted

aluminum.

Therefore, a variation of the first embodiment, shown in figure 2, foresees the superimposition of at least two layers 2 of the protective fabric above described. From the structural point of view, in fact, the upper layer 2 which first comes into contact with the aluminum acts as a sacrificial material and cause a sufficient heat loss to the metal, such that the second underlying layer 2 is able to easily stop the same, by protecting the operator.

A graphical representation of the behavior of the textile 1, according to the variation of the first embodiment, when contacting the melted metal, is dia- grammatically shown in figure 9. The outer portion 12 of the warp 3 of the upper layer 2, which directly contacts the melted metal, tends to burn leaving the underlying quartz weft 4 uncovered, which on the contrary is heat resistant. The lower portion 13 of the warp 3 of the upper layer 2, arranged below the weft 4 and contacting with the lower layer 2, is only carbonized or locally burnt.

The lower layer 2 of fabric shows, on the contrary, the upper portion 14 of the warp 3 blackened or slightly carbonized, while the lower portion 15 of the warp 3 is perfectly intact. The quartz weft 4 of the

lower layer 2 is heat resistant, is not damaged and is not even uncovered.

A second embodiment of the protective textile I ₇ shown in figure 3, foresees at least a protective fabric layer 2, including a warp 3 made of para-aramidic fibers and a weft 4 made of a 100% quartz fiber, externally coated with at least a protective textile layer 7 intended for coming into direct contact with the melted materials. The fabric layer 2 shows an upper surface 6 which is advantageously coated with the protective textile layer 7.

Such layer 7 of protective textile is preferably fireproof and acts as a sacrificial material, since it is first impaired by the melted materials which accidentally hit the protective material, as a double protective barrier and a protection for the underlying para- aramidic fibers. In fact, as it is known, the para- aramidic fibers degrade by the action of the ultravio- let rays and for this reason it is preferable if they are protected by any fireproof material. Preferably, the protective material 7 used consists of meta-aramidic fibers. Alternatively, it is also possible to use a cloth or any other fireproof, and possi- bly light, textile capable of protecting the para-

aramidic fibers from the UV rays, thus avoiding any possible burning of the upper surface 6. From experimental tests, graphically reported in the figures 11-16 and carried out according to the speci- fication CENT/TC 161/WG1 N114 dated March 2006 and following the procedure described in the paragraph A.6 of such specification, it has been ascertained that the material 7 is blackened, carbonized or slightly burnt in some zones 16 by the action of drops of melted materials, such as iron, figure 11, or stainless steel, figure 13, while it is burnt in a more remarkable way by the contact with melted aluminum, , figure 15, leaving the underlying layer 2 locally visible. At the middle of the burnt zones 17 of figure 15, in fact, the weave of the underlying fabric layer 2 is visible.

As it can be seen from figures 11 an 13, on the contrary, the action of the melted iron and the melted steel, respectively, does not damage the layer of pro- tective material 7.

Figures 12, 14 and 16, on the contrary, show the lower surface of the fabric layer 2 placed below the protective material 7, namely show the surface which contacts the user. In case of textile 1 contacting with melted iron or stainless steel, figures 12 and 14, the

underlying fabric layer 2 is not impaired. In case of textile 1 contacting with melted aluminum, figure 16, the underlying fabric layer 2 shows some blackened points 18 or at most slightly carbonized, but only lo- cally.

A first variation, shown in figure 4, of the second embodiment includes at least two layers 2 of the fabric above described superimposed in order to form a double protective barrier. The upper layer 2 shows an upper surface 6 and a lower surface 5, which is into contact with the lower layer 2. The upper surface 6 is advantageously covered by a layer 7 of fireproof protective material, similar to the one above described, and having the same purposes. Also for this variation, experimental tests, always according to the above-mentioned specification, have been carried out, whose results are graphically reported in figures 17-22. Figures 17, 19 and 21 show the protective material 7, The results are of course the same of the preceding case: some blackened or locally carbonized zones 16 following to the contact with melted iron, figure 17, and melted stainless steel, figure 19, whereas some burnt zones 17 which leave the underlying fabric layer 2 uncovered, in case of contact with melted aluminum,

figure 21.

The two fabric layers 2 arranged below the protective material 7 are perfectly intact and do not show, not even locally, blackened zones, as it can be clearly seen by figures 18 and 20.

The double fabric layer 2, coated by the protective material 7, perfectly protects also from the melting splashes of aluminum: in fact, on the lower surface of the lower fabric layer 2 contacting with the user's skin, burning marks are not observed, not even locally, as shown by figure 22.

The weight of the fireproof material layer 7 alone is in the order of about 100 g/m ² . Therefore, the total weight of the protective textile formed by two layers 2 of protective fabric and by one outer layer of fireproof material is of about 600-700 g/m ² , preferably 630-650 g/m ² , also considering the binders which keep together the different layers. The textile 1 thus formed results flexible and suffi- ciently light to be easily used in the protections of footwear and clothing, being resistant to the action of any melted material.

A second variation, shown in figure 5, foresees at least two layers 2 of protective fabric alternated with at least two layers 7 of fireproof material. It

should be noted that at least one layer 7 of fireproof material always covers the upper surface 6 of the outermost fabric layer 2.

The textile 1 includes at least a structure consisting of at least two fabric layers 2 and at least two alternated layers 7 of fireproof material, but advantageously it can be carried out by alternatively combining, as one wishes, a number of protective fabric layers 2 and fireproof material layers 7. A third embodiment, shown in figure β, of the textile 1 includes at least a fabric layer 2 having both the surfaces 8a and 8b coated with a fireproof material layer 7. Also for this embodiment, the fabric layer 2 prefera- bly consists of a warp 3 of para-aramidic fiber and a weft 4 of 100% quartz fiber.

The fireproof material 7 is preferably a polyurethane resin 9, enriched with ceramic materials, preferably micro-spheres of silicates 11, and/or quaternary aitimo- nium salts 10, spread on both the surfaces 8a and 8b. The ammonium salts 10 play a function known as "flame retardant", namely they inhibit development of a living flame, while the ceramic materials tend to absorb and dissipate the heat coming from the melted metal. The combined action of the ammonium salts 10 and the

ceramic materials not only prevents the polyurethane resin 9 from burning but imparts to the same some protective properties with respect to the melted metals, which are added to those of the interposed fabric layer 2 based on para-aramidic fibers and quartz fiber.

Experimental tests, always carried out according to the above-mentioned specification on the textile according to this third embodiment and reported in fig- ure 23, have pointed out how this material perfectly acts as a protective barrier. Only the upper layer 7 of fireproof material, visible in figure 23, is attacked by welding splashes or drops of melted metal, leaving completely intact both the underlying layer 2 and the second fireproof material 7.

The presence of the double layer 7 of fireproof material reduces the number of protective fabric layers 2 by therefore decreasing the thickness, the total weight and the production costs of the textile 1. The protective textile 1, carried out according to the third embodiment, is more readily processed, thanks to the double coating which avoids possible fraying, or shear unravelling, and lighter to wear, thus improving the comfort and the ergonomics of the clothing item carried out with such material.

A fourth embodiment, shown in figure 7, envisages the use of at least a protective fabric layer 2, with a different composition and weft and warp structure. In particular, the fabric layer 2 includes a warp 3 consisting of a two-stranded twisted yarn made of a 100% meta-aramidic fiber, having a resulting fineness varying between 15 and 45 Nm, preferably between 25 and 35 Nm, still more preferably of 30 Nm, and a density varying between 25 and 45 yarns/cm, preferably between 30 and 40 yarns/cm, still more preferably of 36 yarns/cm. The fabric provides a double face of weft 4, of which preferably a first yarns series 4a consists of a two-stranded twisted yarn made of a 100% meta-aramidic fiber while the second yarn series 4b consists of a two-stranded twisted yarn made of a 100% quartz fiber. Alternatively, both the first series 4a and the second series 4b of weft consist of aramidic fiber and quartz fiber, twisted together, or simply placed side by side or alternated. Both the weft series 4a and 4b have each a resulting fineness varying between 15 and 45 Nm, preferably between 25 and 35 Nm, still more preferably of 30 Nm, and a density varying between 9 and 20 yarns/cm, preferably of 14 yarns/cm. Advantageously, the fabric layer 2 includes at least 20% of quartz fiber.

The single fabric layer 2, according with this fourth embodiment, has a weight of about 180-250 g/m ² , preferably between 200 and 220 g/m ² .

Also on this embodiment of the protective textile 1, some experimental tests have been carried out. The results obtained by the dripping test, carried out according to the specification CENT/TC 161/WG1 N114 dated March 2006, following the procedure described in the paragraph A. β of such instruction, on the upper surface β of a single fabric layer 2, have provided positive results in case of drops of melted iron, steel and copper.

Particularly, it has been ascertained that the fabric layer 2 thus obtained is capable of withstanding the passage of different melted materials, and particularly the melted metals, such as for example the casting splashes produced by the welding of iron, steel or copper. It has been noted, in fact, that the outer surface 12 of the warp 3, which consists of irieta- aramidic fibers, when contacting the melted metal tends to carbonize or locally burn, leaving partially uncovered in some points and intact the underlying second weft series 4b made of quartz yarns, as it can be seen in figure 24. This latter is well resistant to the high melting temperatures and prevents the passage

of drops of melted metal, loosing only a very little part of its dimensional resistance. In this way, the surface 13 of the warp 3, placed below the second weft series 4b, is not degraded by the heat and is only lo- cally carbonized, figure 25. The first weft series 4b made of meta-aramidic fibers, on the contrary, tends to burn.

A variation of this embodiment, shown in figure 8, is given by the superimposition of at least two layers of the fabric above described. It is however possible to superimpose a desired number of fabric layers 2, depending on the requirement, for example varying between two and six. Preferably, from two to four layers 2 of the described fabric can be superimposed. Also for this variation, experimental dripping tests of melted iron, whose results are reported in figures 24-27, have been carried out.

Particularly, figures 24 and 25 represent what happens to the first fabric layer 2 which comes into contact with melted iron, as above described.

Figures 26 and 27 show what happens to the underlying layer, in particular to the upper surface 14 of the lower layer 2, figure 26, and the lower surface 15 of the lower layer 2, figure 26. In both cases, the surface is almost integral and does

not show burning marks, perfectly protecting the user. The protective textile 1, including at least two layers 2 of the above described protective fabric, is also resistant to the passage of melted aluminum and all those melted materials having a heat capacity similar to that of aluminum. Also in this case, the first layer 2, the upper one entering into direct contact with the melted material, acts as a sacrificial fiber, while the second underlying layer 2 plays the real protective action. In particular, the quartz yarn is not weakened by the temperature of the various melted materials and keeps the dimensional resistances of the fabric, by effectively protecting the meta- aramidic fiber from the high temperatures which other- wise would cause the decomposition thereof. The fabric is thus capable of effectively protecting the user. From the experimental tests carried out by dripping of melted aluminum according to the above instruction, whose results are diagrammatically represented in fig- ure 10 and graphically in figures 28-31, it should be noted that the outer portion 12 of the warp 3 of the upper layer 2, figure 28, which comes into direct contact with the melted metal, the first weft series 4a and part of the warp 12a interposed between the two weft series, tend to burn leaving the underlying sec-

ond quartz weft series 4b uncovered, which on the contrary is resistant to heat. The lower portion 13 of the warp 3 of the upper layer 2, figure 29, arranged below the second weft series 4b and contacting with the lower layer 2, is only carbonized or locally burnt .

The lower layer 2 of fabric, on the contrary, shows the upper portion 14 of the warp 3, figure 30, blackened or slightly carbonized, while the lower portion 15 of the warp 3 is perfectly intact, figure 31. Both the weft series 4a and 4b of the lower layer 2 are heat resistant, are not impaired and are not even uncovered. It should be noted, however, that it is possible to carry out a protective textile 1 according to the present invention including at least a fabric layer 2 obtained by combining, in the more suitable way and based on the features of the materials, a quartz fiber with an aramidic, meta-aramidic, para-aramidic, moda- crylic or flame retardant viscose fiber or any other fiber having a decomposition point higher than 400 ⁰ C, or a LOI (limiting oxygen index) value higher than 30. The above fibers can be arranged in the weft or in the warp or in both directions, depending on the proper- ties that one wishes to impart to the material, and

with the more suitable percentages. In case of weft and/or warp consisting of both aramidic and quartz fibers, it is possible to alternate, place side by side or twist together the different fibers. The preparation of the aforesaid fabrics is carried out with techniques and devices known to the skilled in the art.

The textile according to the present invention is suitable for being used for the preparation of any protective garment against the action of melted materials, such as melted metals, asphalt, ceramic materials and the like.