WO2009153345A2

WO2009153345A2 - Process for decolorizing and/or aging fabrics, and decolorized and/or aged fabrics obtainable therefrom

Info

Publication number: WO2009153345A2
Application number: PCT/EP2009/057686
Authority: WO
Inventors: Francesco Ricci
Original assignee: Golden Trade S.R.L.
Priority date: 2008-06-20
Filing date: 2009-06-19
Publication date: 2009-12-23
Also published as: WO2009153345A3

Abstract

A process for decolorizing and or/aging fabrics is described, comprising treating the fabrics with porous granules of an expanded polymeric mixture, said granules having density equal to or greater than 1.0 g/ml, and average pore diameter ranging from 0.001 and 5 mm; the process may be carried out both as a dry treatment, preferably in the presence of an oxidizing substance, and as a wet treatment in a bath.

Description

PROCESS FOR DECOLORIZING AND/OR AGING FABRICS, AND DECOLORIZED AND/OR AGED FABRICS OBTAINABLE THEREFROM

FIELD OF THE INVENTION The present Invention relates to a process for decolorizing and/or aging fabrics, both as raw fabrics and as sewed clothes, in a more or less uniform way, and to decolorized and/or aged fabrics obtainable by said process. BACKGROUND QF THE INVENTION

The textile and clothing industry is a very dynamic field, always searching for new products, new articles and new technological solutions; in particular, fashion trends have an enormous influence on the finishing treatment of textiles. There is in fact a continuous and increasing interest with respect to products which from the moment of purchase have a more or less uniform aged or decolorized effect. Treatments which lead to the decolorizing and/or aging of fabrics or clothes are particu- larly widespread, especially in the range of fabric finishing treatment. This is particularly the case of Denim fabric, which represents about 2/3 of the overall sportswear market.

Various methods for decolorizing fabrics and/or clothes are known in the art and currently used; these techniques are commonly defined as Stone Wash. The term Stone Wash comprises an extremely wide variety of aging techniques which are however all linked by the use of carriers having strong abrading and absorbing characteristics. Among these, as will be seen hereunder, pumice stone is particularly preferred.

The Stone Wash techniques are not limited to the finishing of Denim, but are also applied to other fabrics, mainly cotton, such as velvet, canvas, popeline and knitwear.

A type of treatment commonly used in the art for obtaining a decolorizing effect on fabrics or items of clothing comprise the treatment of such fabrics or items with solutions of oxidizing compounds, such as sodium hypochlorite, which exerts an oxidizing action on the fabric and thus cause a bleaching of the same. The bleaching effect may be more or less evident depending, for example, on the time of action and on the concentration of the solutions of oxidizing agent. These methods which operate in a bath, however, only allow products having a different decolorizing and/or aging effect, which is almost uniform, to be obtained, making a non- homogeneous decolorizing quite difficult.

In order to obtain the non-uniform decolorizing and/or aging of fabrics or clothes, further methods were developed. US 4,575,887 for instance discloses a method of abrading fabric garments in a washing machine filled with sufficient hot water to cover the garments; small sized abrasive particles, such as pumice sand particles, are added to the machine and agitated until the garments are uniformly abraded. The decolorizing action is the result of the prolonged abrasion due to the continuous movement of the bath which causes the abrading materials to uniformly age the fabrics.

EP238779 concerns a method of abrading fabric garments in a washing ma- chine with a rotating drum, wherein pumice granules are impregnated with a bleaching agent; by agitating the dry cloths or garments with the impregnated granules for a defined period of time, a desired decolouring of the cloth may be obtained. The method may be carried out as a dry treatment or in a bath. The dry treatment may be carried out on dry or wet clothes, in particular drums specialized for the dry decolorizing phase, whereas the preparatory phases of the fabrics to be treated and the final neutralization phases are effected in different machines, such as industrial washing machines. According to this method, the impregnated granules cause a decolorizing only in the points where the abrading materials enter into contact with the fabrics to be decolorized. The treatments known in the art comprise the use of porous carriers, which exert a mechanical abrasion action on the clothes and, at the same time, have the purpose of carrying the bleaching agent, with which the carrier itself is impregnated. Besides pumice and sands, suitable porous carriers comprise natural materials such as silica sand, diatomaceous earth, perlite and leca. Such carriers can be used alone or impregnated with oxidizing agents.

The above mentioned granules of natural materials, such as pumice and sands in general, tend to crumble during the decolorizing phase, either in a bath or with a dry process, thus producing granules of very small dimension which are no longer suitable for exerting an abrading action. Therefore, such materials produce high amounts of waste, in the order of a few kilograms per item of clothing treated, which cannot be reused and must be properly disposed of. Therefore, after the decolorizing and/or aging step, it is necessary to carry out a neutralization step in order to remove the residua) sands or pumice waste from the treated fabrics and to neutralize the traces of oxidizing material still present. This neutralization step leads to the undesired production of a huge quantity of waste sludge, which is difficult and costly to dispose of.

The use of pumice or natural sands presents the following problems;

1) it requires the use of specialized machinery;

2) it leads to the formation of high quantities of processing scraps; 3) the decolorizing effect is difficult to reproduce, due to the different charac- teristics of pumices and in general of carriers of natural origin. For example, in case an oxidising agent is used, the impregnation surface which will come into contact with the fabrics may not be constant. Moreover, granules of pumice or other natural products, with a high hygroscopicity may contain varying percentages of humidity; this characteristic does not ailow to obtain homogeneous results, thus obtaining differences in color shade from cycle to cycle;

4) the use over time of pumice tends to wear and ruin the plates of the rotating drums used for the processing;

5) in the case of light fabrics, the roughness of pumices can cause breakage and defects of the fabrics, due to their excessive abrading action, thus producing a faulty item of clothing which cannot be sold, with serious economical damage;

6) the considerable quantities of fabrics subjected to this type of treatment require an extremely high consumption of pumice. In this respect, it is estimated that every year 5-6 billion meters Denim fabric are produced in the world, with an aver- age use of 1.15 meters of fabric to produce one item of clothing. When considering that 1 to 3 kg of pumice are necessary for aging a finished item of clothing, it is evident that the above aging techniques using pumice cause a significant ecological problem, linked not only to the disposai of treatment residual sands, but also to the fact that every year actual mountains disappear (see for example the problem of the island of Lipari in Italy).

Other methods known in the art have tried to overcome the problems associated to the use of purnice, for instance by using polymeric materials. US 5,514,192 (Grisby, Jr.) describes the use of plastic stones in a stonewashing process to age garments or fabrics; the plastic stones, made preferably of polystyrene, have a den- sity similar to that of pumice stone, and are used in a wet process without the use of oxidizing agents. These plastic stones do not give satisfactory resutts in acceptable industrial times because during the action the pebble surface tends to become smooth.

US 5,093,948 (VaI et al.) concerns a process of premature wear of textile ar- tides, comprising the use of bodies, preferably of spherical form, coated with a layer of flexible material having defined hardness and index of compression. The flexible materia! is preferably an elastomer, such as polybutadlene. The process, which avoids the use of materials having abrasive capabilities, do not give satisfactory aging results in view of the poor abrasive activity of the flexible material. US 5,535,469 (Terry) discloses the use of pellets for abrading fabrics during a wash cycle. The pellets comprise a mixture of plastic resin, such as PVC, a piasti- cizer, such as bis(2-ethylhexyl)terephthalate, and an abrasive filler, such as aluminium trihydrate. These pellets, which are hard at room temperature, become pliant at normal wash water temperatures. This method is only limited to wet decolorizing procedures, carried out in a bath and gives unsatisfactory aging results in industrial processes because during the action the pellets become pliant and the pellet surface tends to become smooth.

The present invention therefore proposes to find a process for decolorizing and/or aging fabrics, which can be carried out both as a dry treatment and in a bath, which is able to give satisfactory results, in a reproducible way and in acceptable treatment times, at the same time overcoming the drawbacks of the processes using pumice or natural sands,

SUMMARY OF THE INVENTION

The Applicant has found that the above problems are solved with the proc- ss of the present invention, for decolorizing and/or aging a fabric, which comprises treating the fabric with porous granules of an expanded polymeric mixture, the granules having density equal to or greater than 1.0 g/ml, and average pore diameter ranging from 0,001 and 5 mm. The process may be carried out with a dry procedure, optionally impregnating the granules with an oxidizing substance, or in a bath. According to a preferred embodiment, the expanded polymeric mixture comprise from 10 to 70%wt of a polymer material and from 30 to 90%wt of at least one filler; the expanded polymeric mixture may further comprise from 0 to 7% of at least one additive.

A further object of the present invention is a decolorized and/or aged fabric obtainable by the process of the invention.

A further object of the present invention relates to the use of porous granules of an expanded polymeric mixture for decolorizing and/or aging fabrics, the granules having density equal to or greater than 1.0 g/ml, and average pore diameter ranging from 0.001 and 5 mm; the granules may be used in a dry process or in a bath. Finally, the present invention refers to porous granules of an expanded polymeric mixture, having density equal to or greater than 1.0 g/ml, average pore diameter ranging from 0.001 and 5 mm, melting point higher than 120°C and Shore D hardness higher than 20.

DETAILED DESCRIPTION OF THE INVENTION The process according to the present invention allows to obtain an effect of discoloration and/or aging which is equal or even improved with respect to the results obtained for example when pumice is used, as described in US 4,575,887 and EP238779, at the same time avoiding the disadvantages associated to pumice. Further advantages of the process of the present invention are the following: the proc- ess does not require the use of specialized machinery; the process does not dam- age the machinery used; there is no relevant formation of processing scraps; the discoloration/aging results are substantially repeatable; the process may also be carried out on lighter fabrics. Moreover, the treatment is economically more advantageous than the use of pumice, because it does not require the elimination phase of the waste or sands, and allows a complete re-use of the decolorizing and/or aging granules. In fact, with respect to the use of pumice, the expanded polymeric granules, when subjected to beating and impact in the rotation phase in the drum, do not crumble and substantially maintain their initial dimension; the granules may be therefore re-used once the treatment has been completed. The granules of expanded polymeric mixture used in the process of the invention have a density equal to or greater than 1.0 g/ml, preferably from 1.1 g/ml to 2.5 g/ml, and more preferably from 1.2 to 1.75 g/ml. The granules have porous structure with an average pore diameter ranging from 0.001 and 5 mm, preferably from 0.1 mm to 4.5 mm, and more preferably from 0.5 to 2.5 mm. The granules have water absorption values, measured according to the

ASTM method D 570-98, preferably ranging from 4 to 30%, more preferably from 5 to 20%.

The polymeric mixture preferably comprises:

- from 10 to 70%wt, preferably 12 to 60%wt, and even more preferably from 15 to 45%wt of a polymeric material; and

- from 30 to 90%wt, preferably from 40 to 88%wt, and even more preferably from 55 to 85%wt of at least one filler.

The polymeric material can comprise one or more polymers selected from the group consisting of polyolefins comprising one or more Ci-C₆o alpha-olefin mono- mers (such as polypropylene, polybuteπe and polyethylene - high density HDPE₁ low density LDPE and linear low density LLDPE)₁ polyvinylchloride (PVC), acryloni- trile-butadieπe-styrene (ABS) polymers, styrene-butadiene (SBR) rubbers, epoxy resins, melamine resins, polyamides, polybutyleneterephthalate, polycarbonate, polyethyleneterephthalate, phenolic resins, polymethylmethacrylate, polystyrene, polysulfone, polytetrafluoroethylene, polyurethane, potyvinylacetate, polyester, ureic resins and/or mixtures thereof. The polymeric material can also comprise PUR glue (glue based on reactive polyurethane) monocomponents or bicomponents, epoxy glue bicomponents, ureic glue, vinyl glue, cyanoacrylates, EVA glue and mixtures thereof. According to a preferred embodiment, the polymeric material is selected from homopolymers or copolymers of one or more C-₁-C₂₀ alpha-olefins, preferably selected from the group consisting of ethylene, propylene, 1-butene, 1-hexene, 1- octene, 1-decene, 1-dodecene, and mixtures thereof.

According to a further preferred embodiment of the invention, the polymeric material comprises:

- 30-95% by weight, preferably 40-80% by weight, of a homopolymer of propylene, or a copolymer of propylene with ethylene or a 04-C_1O alpha-olefin, wherein the amount of ethylene or the CrC₁₀ aipha-olefin is lower than 10%by weight, preferably ranging from 1 to 5% by weight; - 3-20% by weight, preferably 5-15% by weight, of a copolymer of propylene or ethylene with a different C2-C₁Q alpha-olefin, said different C₂-C1₀ alpha-olefin being present in an amount lower than 50% by weight, preferably ranging from 10 to 40% by weight; and

- 0-50% by weight, preferably 10-40% by weight, of an ethylene polymer. The filler is preferably a mineral filler; suitable fillers for the polymer mixture used in the process of the invention are selected from the group consisting of talc, sifica, clays, wollastonite, diatomaceous earths, zeolites, glass fibers or powder or granules, calcium carbonate, barium sulfate, pumice sands, titanium oxide, manganese oxide, zirconium oxide, quartzes, magnesium hydroxide, aluminum hydroxide and mixtures thereof.

The filler can have an average particle size varying from 0.2 micrometer to 1500 micrometers, preferably from 100 to 1000 micrometers, and even more preferably from 300 to 800 micrometers. According to a preferred embodiment of the invention, from 20 to 70%wt of the filler has a particle size ranging from 300 to 800 micrometers.

Without being bound by theory, it is believed that the considerable amount of filler in the expanded polymeric mixture of the granules, as well as the defined particle size of the filler, allow to obtain granules having a high amount of pores constantly available on the outer surface of the granules themselves. In fact, while the polymeric material guarantees a porous material having the required characteristics of hardness, abrasion and compression set, it is believed that the considerable amount of filler with defined particle size causes the granules to crumble only superficially, thus exposing new porosity to the outer surface, and guaranteeing a constant abrading action during the decolorizing process. In addition to the components discussed above, the polymeric mixture may further comprise one or more additives commonly employed in the polymer field, such as antioxidants, stabilizers (such as light stabilizers and anti-UV stabilizers), nucleating agents, antiacids and pigments. Such additives are preferably comprised in the polymeric mixture in amount ranging from 0 to 7%, more preferably from 0.1 to 5% Wt, and even more preferably from 0.5 to 4%wt. The granules of expanded polymeric mixture preferably have a melting point higher than 12O⁰C₁ more preferably higher than 14O⁰C. The Shore D hardness of the expanded polymeric granules is preferably higher than 20, more preferably higher than 30. The Melt Index of the expanded granules preferably ranges from 1 to 100 g/10min, more preferably from 5 to 70 g/10min, and even more preferably from 8 to 50 g/10min.

The granules of expanded polymeric mixture can be obtained by expansion, obtained in an autoclave or by means of an extruder; preferably the granules are obtained by extruding the polymeric mixture in the presence of one or more foaming agents. Before expansion, the polymeric mixture may have a density higher than 1.0 g/rnl, preferably from 1.1 g/ml to 3.4 g/ml, more preferably from 1.3 g/ml to 2.1 g/ml. The flexural modulus of the polymeric mixture before expansion may be greater than 1,000 MPa₁ preferably greater than 2.000 MPa, more preferably greater than 3,000 MPa. The Shore D hardness of the polymeric mixture before expansion may be greater than 50, and preferably greater than 70.

Foaming agents, also referred to as blowing or expanding agents, can be either chemical foaming agents or physical gas/liquids. Chemical foaming agents are compounds which react or decompose in a polymer melt during processing at elevated temperatures, such as those employed in extrusion, to give a product that is normally a gas at atmospheric pressure. Suitable chemical foaming agents are calcium oxide, azodicarbonamide, sulfonyl hydrazides, n-nitroso compounds (especially dinitroso pentamethylene tetramine), semicarbazides, tetrazoies, alkali carbonates and bicarbonates (such as sodium bicarbonate) or mixtures thereof, optionally in blend with organic acids, such as citric or tartaric acid as co-agents. These agents are typically in dry powder form and are used as such or as master-batches, which are added to the polymeric mixture prior to introduction into the extrusion equipment. Alkali carbonate mixtures suitable as chemical foaming agents are commercialised by Clariant under the trademark Hydrocerol™ or by Hoechst CeIa- nese under the trademark Hostatron™. Generally these products are in the form of master-batches, containing 20-80%wt. of foaming agent.

Suitable liquids which can be advantageously used as foaming agents are hydrocarbons, possibly fluorinated or chlorinated, having a boiling point higher than 25⁰C, such as for example pentane, hexane, dichlorotrifluoroethane, CFC-11 , CFC- 12, CFC-114, HCFC-22, HFC-152a and methylene chloride. Liquid or gaseous foaming agents, having a boiling point lower than 25°C can also be used, such as for example air, nitrogen, CO₂, chlorodifluoromethane, dichlorodifluoromethane, butane, propane and isobutane.

In order to increase the roughness of the granules, the polymeric mixture may be hot extruded through an extrusion head having an irregular section, prefera- bly star- or crown-shaped. In order to further increase the outer ruggedness or roughness of the granules, air jets can be used in correspondence of the cutting blade or on the outlet mouth of the extruder, wherein the cutting blade can in turn have an indented, irregular saw-shaped conformation.

The extrusion process for producing the granules may comprise a mixing phase of the polymer material with suitable fillers and with the expanding agents. The obtained material is subsequently introduced into the heating chamber of the extruder, where it not only melts as a result of the heat received, but it is also mixed due to the rotation of the worm screws inside the jacket of the extruder and, as a result of the gases produced by the expanding agent, it swells. The extruded product thus leaves the extruder head having a porosity and alveoli over the whole surface of the materia! still molten, both Internally arid externally. The expansion phase may be assisted by jets of air in correspondence of the outlet mouth of the extruded granules. At the head outlet, the molten material is cut into the desired dimensions and immediately sent to a cooling plant in order to maintain and block the morphol- ogy of the material thus obtained. In some cases, there can be a further refining phase of the extruded granules, consisting in a peeling operation of the granules. This operation has the double purpose of providing granules with more regular dimensions and expose part of the internal porosity to the outer surface of the granules. Once the extruded and expanded granule has been brought to room tempera- ture, it is refined and brought to the desired particle-size by mechanical peeling.

Alternatively, the porosity of the expanded granules may be obtained by mixing the polymeric mixture with a solid particulate material soluble in a solvent, and forming granules thereof, thus at least partially encapsulating the particulate material in the granules. After formation of the granules, the particulate material may be dis- solved with the solvent, thus leaving a plurality of recesses, some of which are open to the outer surface of the granules. By using a solid particulate material during the formation of granules, for instance by extrusion (in the absence of foaming agents), the size of the recesses and the corresponding granules porosity can be controlled by the size of the solid particulate material being used. Suitable solid particulate ma- terials are salts of alkali or alkaline earth metals which are water soluble, and in particular sodium bicarbonate.

The granules used in the process of the present invention preferably have a rounded form, more preferably spherical, with diameter ranging from 0.001 mm to

100 mm, preferably from 3 mm to 40 mm; the granules can also have a rounded cy- lindrical form with diameter varying from 0.001 mm to 100 mm, preferably from 3 to 40 mm, and length ranging from 0.001 mm to 100 mm, preferably from 3 to 40 mm.

The process of the invention may be carried out in a bath or may be dry.

When the "stonewashing" process is carried out in a bath, the granules are put in contact with the fabric and desired chemicals, and rotated in the presence of a bath for a defined time.

When the process is dry, the granules are preferably put in contact with the fabric, dry, damp or centrifuged after a norma! washing bath, dry rotating, i.e. in the absence of a bath, for a defined time. The granules, commonly placed in a rotating drum together with the fabric, are wetted or impregnated with an oxidizing sub- stance. Suitable oxidizing substances are selected from sodium hypochlorite, sodium chlorite, sodium persulfate, sodium hyposulfite, potassium permanganate, potassium persulfate and mixtures thereof, and are commonly used in the form of aqueous solutions. Before use, the granules are impregnated or wetted with the oxidizing substance, which tends to saturate the surface of the granule. It is well known that when liquid and solid are in contact, due to the interactions between the different phases, an interfacial tension defined as additional energy is established per unit of area due to the formation of a solid/liquid interface. Surface tension is a particular property of fluids which operates along the separation line (interface) between the fluid itself and a material of another nature, for example a solid, liquid or a gas. The wettability, favoured by low interfacial energy, high surface energy and modest surface tensions, with the same wetting liquid and type of solid material, fs strongly influenced by the state of smoothness and presence of impurities on the surface of the material itself. In the case of the granules used in the process of the invention, the increase in surface due to roughness and surface porosity of the granules in- creases the wettability or absorbance of the granules themselves. The expanded polymeric granules used in the process of the invention can have a more or less smooth/rough conformation, according to the use; they have a good absorbing capacity of the oxidizing product, together with an optimum resistance to oxidizing agents, alkalis, acids and, as already mentioned, to impact, as they are capable of absorbing impact.

Depending on the desired decolorizing and/or aging effect, it is sufficient to operate with suitable ratios of fabrics to be decolorized/granules; the weight ratio fabrics to be treated/granules can vary from 1/0.01 to 1/50, preferably from 1/1 to 1/15. Once the granules of expanded polymeric material have reached the end of their operational life, i.e. when the dimensions have become so small that the granules could end up in the wastepipe in the case of perforated rotating drums, they can be collected from the waste discharge or discharge accumulation tanks, and brought for regeneration and subsequent re-use. The material may then be melted again, re-expanded and then re-used in the process of the invention.

The process according to the present invention allows a decolorized and/or aged fabric to be produced with satisfactory results, in a reproducible way and in acceptable treatment times, at the same time overcoming the drawbacks of the processes using pumice or natural sands. Depending on the morphology of the fabrics treated in a dry process, the decolorized shade may be very light and evident on the outer parts of the clothing and tends to diminish in the internal parts, as it moves away from the edges of the apparel to be treated.

The process according to the present invention can be carried out on any type of fabrics. By the term "fabrics", it is meant herein textiles (i.e. any materials made of interlacing fibres), fabrics (i.e. any materials made through weaving, knitting, crocheting, or bonding), as well as cloths (i.e. finished pieces of fabrics or textiles, such as garments and sewed items). The fabrics may be natural or synthetic, and in particular may be made of cotton, denim, knitwear, leather, as well as silk, such as chiffon, fn fact, the process of the present invention is extremely "delicate" and "respectful" with respect to the fabric, in view of the fact that the granules used for decolorizing and/or aging are able to absorb impact which could damage the fabric. Therefore, the process of the invention may be advantageously used for the decolorizing and aging of silk and chiffon fabrics, obtaining a more or less uniformly decolorized and/or aged end-product.

The process of the Invention presents many advantages with respect to pumice, which is industrially used nowadays to obtain stone wash treatments. For instance, the consumption of the expanded granules is only 1-2% of the pumice consumption, in view of the higher duration of the granules with respect to pumice; moreover, pumice tends to crumble and to produce silica powders, which are extremely harmful to the health of the operators. Also the cost of the expanded granules is highly competitive and convenient with respect to the cost of pumice, since the problems related to logistics and transportation can be highly reduced.

The decolorizing and/or aging process according to the present invention can be precisely and accurately controlled. Furthermore, the machines involved (washing machines, dryers, rotating drums, pumps and plants) are subject to considerably reduced wear.

The process of the invention is also much more versatile with respect to the use of pumice, and can be tuned in a repeatable way in line with the fashion trends of the market, depending on the type of fabric to be treated and/or the specific type of treatment to be effected. In fact, the porosity of the granules may be controlled and varied to obtain a defined level of decolorizing and aging of the final fabric.

The process of the invention may also be carried out by an end-user, who wishes to proceed with a personalized approach with the decolorizing and/or aging of a fabric, according to his own preferences, at home, by using household washing machines.

In a dry process where an oxidizing agent is used, it is also possible to operate in a single apparatus, in which both the decolorizing and/or aging phase and the subsequent neutralization phase are effected, always in the same machine and with the possibility of using a household washing machine, as mentioned above. This is not possible when pumice is used.

The present invention a!so concerns a decolorized and/or aged fabric obtainable by the process of the invention, as described above.

The present invention is also directed to the use of porous granules of an expanded polymeric mixture for decolorizing and/or aging fabrics, the granules having density equal to or greater than 1.0 g/ml₍ and a porous structure with an average pore diameter ranging from 0.001 and 5 mm. The granules may be used in a dry process or in a bath, as described above.

The present invention is also directed to porous granules of an expanded polymeric mixture, having density equal to or greater than 1.0 g/rni, average pore diameter ranging from 0.001 and 5 mm, melting point higher than 120⁰C and Shore D hardness higher than 20.

The granules density preferably ranges from 1.1 g/ml to 2.5 g/ml, and more preferably from 1.2 to 1.75 g/ml. The average pore diameter preferably ranges from 0.1 mm to 4.5 mm, and more preferably from 0.5 to 2.5 mm. The granules melting point is preferably higher than 140⁰C. The granules Shore D hardness is preferably higher than 30.

The properties indicated in the exampies and description were measured as described below. Pore diameter: average pore diameter, measured with optica! microscope; a stereo microscope MEF4M, commercialized by Leica, was used.

Water absorption: method ASTM D 570-98, measuring water absorption in the short term; the sample was first maintained for 8 hours at 6O⁰C, and its weight was then evaluated before and after immersion for 24 hours in distilled water. Density: method ASTM-D 792; an analytical lab balance scale XS205DU, commercialized by Mettler Toledo, was used, with ethanol as liquid at 21.8°C. Hardness Shore D: method UNI EN !SO 8681 , at 23⁰C and relative humidity of 50%, carried out on the granules; the result was taken 15 seconds after the load application. A shore durometer ATS Faar, model D, was used. Flexura! modulus; method ISO 178.

Melt index: method ASTM D1238-00, at 23O⁰C and 10kg; the sample was maintained for 8hrs at 6O⁰C, the cutting time was 10 sec and the multiplying factor was 60. The instrument used was a melt flow indexer Twelvindex, commercialized by ATS Faar. Compression modulus; method UNi EN ISO 604, at 23°C, with a speed of 5mrn/min. The instrument used was a dynamometer BTC-FR010TH, A50, commercialized by Zwick Roe!!.

Melting point: DSC according to the method ISO 3146. The following examples are provided for purely illustrative purposes. Example 1

A laboratory extruder of the company Bausano, type MD 30/19, was equipped with a star-shaped outlet head. The mouth downstream of the extruder before the star profile was 13.00 mm in diameter, whereas the degassfng plant with which the machine is equipped was excluded.

The extruder was fed, by means of a volumetric distributor, with: - 100 parts by weight of Fragom PR55PP, commercialized by Crosspoiimeri S. p. A. consisting of 20% by weight propylene homopolymer, 12% by weight of propylene/ethylene copolymer, 63% by weight of a mixture of Mg(OH)₂ and CaCθ₃, and 5% by weight of stabilizing agents, antioxidants and lubricants;

- 15 parts by weight of Hostatron P1941 , foaming agent commercialized by Hoechst Celanese;

- 2.5 parts by weight of epoxidized soya oil; and

- 25 parts by weight of glass granules having a diameter ranging from 100 to 400 micrometers.

The extruder, having seven different heating points, was brought respectively to: 125⁰C, 18O⁰C, 18Q°C, 220⁰C, 240⁰C, 250⁰C, 265⁵C. A rotating cutter with an air jet, directed onto the extruded material, was assembled on the outlet mouth of the extruder. The resulting granules were dropped into a water cooling plant and were subsequently collected and packaged. Granules of expanded polymeric material were thus obtained, having a diameter size ranging from 2 to 3 cm; the characterization of the obtained granules is reported in Table 1. Example 2

A commercial twin screw extruder of the company Bausano, type MD.125/30 PLUS, was equipped with a star-shaped outlet head, having a 12 star profile. The extruder was fed with a polymeric mixture comprising:

- 38%wt of a composition comprising 20%wt Adstif HA840R, commercialized by Basell Polyolefins, 12%wt Hifax 7254XEP₁ commercialized by Basell Polyolefins, 63%wt of mineral fillers (28%wt Mg(OH)₂, 28%wt CaCO₃ and 7%wt AI(OH)₃) and 5%wt. of stabilizing agents, antioxidants and lubricants;

- 18%wt of Hostatron P1941 , commercialized by Hoechst Celanese; and

- 44%wt glass granules, having average particle size ranging from 400 to 700 micrometers.

The above polymeric mixture was extruded and cut into granules by means of a rotating cutter with an air jet, The resulting granules were dropped into a water cooling plant, collected and packaged. Granules of expanded polymeric material were thus obtained, having a diameter size ranging from 1 to 2 cm. The characterization of the obtained granules is reported in Table 1.

Example 3 The procedure described in Example 2 was repeated, with the difference that the extruder was fed with a polymeric mixture comprising:

- 62%wt of a of a composition comprising 20%wt Adstif HA840R, commercialized by Basell Polyolefins, 12%wt Hifax 7254XEP, commercialized by Basell Polyolefins, 63%wt of mineral filters (28%Wt Mg(OH)₂, 28%wt CaCO₃ and 7%wt AI(OH)₃) and 5%wt. of stabilizing agents, antioxidants and lubricants;

- 2%wt of Hydrocerot HK70, foaming agent commercialised by Clariant;

- 9%wt of Hostatron P1941, foaming agent commercialized by Hoechst Celanese;

- 1 %wt azodicarbonamide as foaming agent; and

- 26%wt glass granules, having average particle size ranging from 400 to 700 mi- urometers. Granules of expanded polymeric material were obtained, having a diameter size ranging from 1,5 to 3 cm; the characterization of the obtained granules is reported in Table 1.

Example 4 The procedure described in Example 2 was repeated, with the difference that the extruder was fed with a polymeric mixture comprising:

- 63%wt of a of a composition comprising 20%wt Adstif HA840R, commercialized by Basell Polyolefins, 12%wt Hifax 7254XEP, commercialised by Basell Polyolefins, 63%wt of mineral fillers (28%wt Mg(OH)₂, 28%wt CaCO₃ and 7%wt AI(OH)₃) and 5%wt. of stabilizing agents, antioxidants and lubricants;

- 4%wt of Hydrocerol HK70, foaming agent commercialised by Clariant; and

- 33%wt brucite granules, having average particle size ranging from 50 to 100 micrometers.

Granules of expanded polymeric material were obtained, having diameter ranging from 1.5 to 2 cm; the characterization of the granules is reported in Table 1. Table 1

Example 5

40 Kg of expanded polymeric granules, obtained as described in each one of Examples 1, 2, 3 and 4 were separately immersed in a solution at 2% of potassium permanganate for 3 minutes.

Said granules were then separately introduced into a rotating drum of Clai- nox model TIC50 at a rate of 27 revs. Ten cotton sweaters, previously prepared and dyed, having a weight of about 3800 g, with a dry feel, were then introduced into the drum. The drum was dry rotated for about 10 minutes (i.e. without adding water, i.e. a washing bath). Said dry decolorizing phase in the washing machine was followed by a normal neutralization phase by introducing water in a suitable quantity, which was then brought to a temperature of 60⁰C. Once this temperature had been reached, sodium bisulphite was added to neutralize the oxidizing agent still present on the fabric and the whole mixture was rotated for 10 minutes with the subsequent discharge of the bath.

Said first neutralization phase was followed by a further rinsing phase in cold water. The treatment was concluded with centrifugation and subsequent drying in a dryer. At the end of the treatment, the clothes had the typical appearance of dry decolorized items.

The granules of polymeric material were re-used for further 52 treatment cycles identical to that described, obtaining treated products with constant qualitative characteristics and identical to those of the first treatment. Comparative example 1

The procedure of Example 5 was repeated under identical conditions, with the only difference that non-expanded granules were adopted, obtained as described in Example 1 but without the use of the expanding agent during extrusion (i.e. Hostatron P1941 was not added). The clothes thus obtained did not have a uniform aging effect, upon visual examination, whereas undesired stains were observed, caused by the bleaching of isolated parts of the fabric.

Comparative example 2

The same treatment as Example 5 was repeated under identical conditions with the only difference that, instead of granules of expanded polymeric material, pumice granule were used, in the same amount. Before treating the clothes, the pumice granules, having average diameter from 1 to 3 cm, were subjected to the impregnation procedure describe din Example 5.

At the end of the treatment the clothes had a decolorized appearance similar to the ne obtained in Example 5. However, only after a single treatment, it was impossible to re-use the same pumice granules, since their quantity was no longer sufficient to respect the ratio clothes/pumice necessary to reach the desired effect. Example 6

10 kg of granules, obtained as described in each one of Examples 1, 2, 3 or 4, were separately Introduced into a Brongo laboratory machine model L60, together with fabrics for 3.5 kg and 40 I of water. The aging cycle effected in a bath was preceded by a desizing treatment under usual conditions, for 8 minutes at 57°C, with an enzymatic solution of amylase 200 g (commercial product OROZlM)₁ in the presence 5Og of PPG2000-Desmophen 2061 (antifoaming agent commercialized by Brenntag), 5Og of Disperdal TC (hydrosoluble oxyethylene polymer mixed with po- lyglycol ether, commercialized by Dalton), and 50 g of Sabopal OC20 (ethoxylated cetyloleic alcohol, 20 moles, commercialized by Sabo). The bath was then discharged and a new bath was charged, comprising 200 g cellulase enzymes in solution, and maintained at 53°C for 60 minutes. The bath was then discharged, three successive rinses were carried out in cold water, a centrifugation treatment and then drying.

At the end of the treatment, the clothes had a characteristic appearance of clothes aged in bath.

The granules of polymeric material were re-used for further fifty-eight treat- ment cycles identical to that described above, obtaining treated products with constant qualitative characteristics and equal to those of the first treatment. Comparative example 3

The procedure of Example 6 was repeated under identical conditions, with the only difference that non-expanded granules were adopted, obtained as de- scribed in Example 1 but without the use of the expanding agent during extru- sion(i.e. Hostatron P1941 was not added).

The clothes thus obtained did not show any relevant abrasion/aging effect upon visual examination.

Comparative example 4 The same treatment as Example 6 was repeated under identical conditions with the only difference that, instead of granules of expanded polymeric material, pumice granules of average diameter ranging from 1 to 3 cm were used, in the same amount.

At the end of the treatment, the clothes had a decolorized appearance similar to the one obtained in Example 5, typical of bath aging.

However, only after a single treatment, it was impossible to re-use the same pumice granules, since their quantity was no longer sufficient to respect the ratio clothes/pumice necessary to reach the desired effect.

Claims

1. A process for decolorizing and/or aging a fabric, which comprises treating the fabric with porous granules of an expanded polymeric mixture, the granules having a density equal to or greater than 1.0 g/ml, and average pore diameter ranging from 0.001 and 5 mm.

2. The process according to claim 1 , wherein the density of the granules ranges from 1.1 g/ml to 2.5 g/ml, preferably from 1.2 to 1.75 g/ml.

3. The process according to claim 1 , wherein the average pore diameter of the granules ranges from 0,1 mm to 4.5 mm, preferably from 0.5 to 2.5 mm.

4. The process according to claim 1, wherein the expanded polymeric mixture comprises from 10 to 70%wt of a polymeric material, and from 30 to 90%wt of at least one filler.

5. The process according to claim 4, wherein the expanded polymeric mixture comprises from 12 to 60%wt, preferably from 15 to 45%wt of a polymeric mate- rial, and from 40 to 88%wt_t preferably from 55 to 85%wt of at least one filler.

6. The process according to claim 4 or 5, wherein the polymeric materia! is selected from homopolymers and copolymers of one or more Ci-C_2O alpha-olefins, preferably selected from the group consisting of ethylene, propylene, 1-butene, 1- hexene, 1-octene, 1-decene, 1-dodecene, and mixtures thereof.

7. The process according to claim 4, wherein the filler is selected from the group consisting of talc, silica, clays, wollastonite, diatomaceous earths, zeolites, glass fibers or powder or granules, calcium carbonate, barium sulfate, pumice sands, titanium oxide, manganese oxide, zirconium oxide, quartzes, magnesium hydroxide, aluminum hydroxide and mixtures thereof.

8. The process according to claim 4 or 7, wherein the filler has an average particle size varying from 0.2 to 1500 micrometers, preferably from 100 to 1000 micrometers.

9. The process according to claim 4, wherein the expanded polymeric mixture further comprises from 0 to 7% of at least one additive selected from the group consisting of antioxidants, stabilizers, nucleating agents, antiacids and pigments.

10. The process according to claim 1, wherein the granules of expanded polymeric mixture have melting point higher than 120°C.

11. The process according to claim 1, wherein the granules of expanded polymeric mixture have Shore D hardness higher than 20.

12. The process according to claim 1, wherein the granules of expanded polymeric mixture have MeSt Index ranging from 1 to 100 g/10min, preferably from 5 to 70 g/10min.

13. The process according to claim 1 , wherein the granules of expanded polymeric mixture have water absorption values ranging from 4 to 30%.

14. The process according to claim 1, wherein the porous granules are obtained by extrusion in the presence of one or more foaming agents.

15. The process according to claim 1 , wherein the porous granules have spherical form, with diameter ranging from 0.001 mm to 100 mm, preferably from 3 mm to 40 mm.

16. The process according to claim 1, wherein the porous granules have cylindrical form, with diameter varying from 0.001 mm to 100 mm and length ranging from 0.001 mm to 100 mm.

17. The process according to claim 1 , wherein the fabric is treated with the porous granules in a bath.

18. The process according to claim 1 , wherein the fabric Is treated, in a dry process, with the porous granules impregnated with an oxidizing substance.

19. The process according to claim 18, wherein the oxidizing substance is selected from the group consisting of sodium hypochlorite, sodium chlorite, sodium persulfate, sodium hyposulfite, potassium permanganate, potassium perεulfate and mixtures thereof.

20. The process according to claim 1 , wherein the fabric is treated with the porous granules in a weight ratio ranging from 1/0.01 to 1/50.

21. A decolorized and/or aged fabric obtainable by the process of any one of claims 1 to 20.

22. Use of porous granules of an expanded polymeric mixture for decolorizing and/or aging a fabric, said granules having density equal to or greater than 1.0 g/ml, and average pore diameter ranging from 0.001 and 5 mm.

23. Porous granules of an expanded polymeric mixture, having density equal to or greater than 1.0 g/ml, average pore diameter ranging from 0.001 and 5 mm, melting point higher than 120⁰C and Shore D hardness higher than 20.

24. The porous granules according to claim 23, wherein the density ranges from 1.1 g/ml to 2.5 g/ml, preferably from 1.2 to 1.75 g/ml.

25. The porous granules according to claim 23, wherein the average pore diameter ranges from 0.1 mm to 4,5 mm, preferably from 0.5 to 2.5 mm.

26. The porous granules according to claim 23, wherein the melting point is higher than 14O⁰C.

27. The porous granules according to claim 23, wherein the Shore D hardness is higher than 30.