WO2000028125A1

WO2000028125A1 - A process for modifying the appearance and surface of textiles, plant for carrying out the method and fabric obtained thereby

Info

Publication number: WO2000028125A1
Application number: PCT/EP1998/007200
Authority: WO
Inventors: Mariano Giannotti
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-11-11
Filing date: 1998-11-11
Publication date: 2000-05-18
Anticipated expiration: 2001-05-11
Also published as: AU1668799A

Abstract

The process for the organoleptic modification of fabrics and clothing items consists in spraying or brushing on the clothing items or fabrics an aqueous mixture of polyurethane resin, partially drying the treated fabric, hot pressing the fabric, and drying it completely to polymerize the mixture; the plant (1) for carrying out said method consists of a sequence of stations placed along a conveyor (2) on which the fabric or clothing item to be treated is placed, said stations being positioning (3), mixture application (4), partial drying (5), pressing (6), calendering (7), and final drying (8); the thus obtained fabric has a structure with vapor-permeable holes and the appearance thereof is plasticized and soft on touch.

Description

A PROCESS FOR MODIFYING THE APPEARANCE AND SURFACE OF TEXTILES, PLANT FOR CARRYING OUT THE METHOD AND FABRIC OBTAINED THERBY

Technical Field

The present invention relates to a process for the organoleptic modification of fabrics and clothing items comprising the steps of: applying on a fabric an aqueous mixture comprising a polyurethane resin, partially drying the treated fabric, hot pressing, and further drying the treated fabric untill a high degree of polymerization of the applied polyurethane resin is obtained. Disclosure of the Invention

The aim of the invention is to provide a process for the organoleptic and surface modification of fabrics and clothing items thus giving them an innovative appearence.

An object of the invention is to provide a process for the regeneration of already used items, thus providing a pleasant aesthetics effect particularly important in the field of fashion.

This aim and other objects are achieved by a process for the organoleptic modification of fabrics and clothing items comprising the steps of applying on a fabric an aqueous mixture comprising a polyurethane resin, partially drying the treated fabric, hot pressing, further drying the treated fabric untill a high degree of polymerization of the applied polyurethane resin is obtained.

The process of the invention can be applied to a wide range of fabrics comprising either natural fibres, such as cotton, wool, leather, and synthetic fibres, such as nylon, polyester, acrylic, etc.

Fabrics can be treated either before or after they are made into clothing items.

The aqueous mixture comprises an amount of polyurethane resin preferably of 15 to 50% by weight, more preferably of 25-35% by weight based on the weight of the water.

Under these conditions, the polyurethane resin is in a highly dispersed form which allows it to be easily and uniformly applied along the fibres of the fabric to be treated.

The polyurethane resin can be of the anionic, cationic or non ionic type, and advantageously it is a polyurethane polyether, polyaminic and polyacrylic resin. The cationic, anionic or non ionic properties of the polyurethane resin arise from the presence of functional groups such as for example the groups OH, NH₂, COO_, etc.

Polyurethanes, which are particularly preferred in carrying out the process of the invention, are those resulting from the reaction among polyisocyanates , particularly diisocyanates, such as amines or polyalcohols.

The application of the water-based polyurethane mixture is by spreading, brushing or spraying, the latter being particularly preferred for obtaining an effective and even distribution of the mixture onto the fabric.

According to an embodiment of the present invention, the water polyurethane mixture further comprises a silicon- based polymer, preferably a polysiloxane.

The addition to the polyurethane mixture of polysiloxane compounds has been found to increase the polyurethane film to fabric adherence during polymerization, while providing in the meantime a softening effect to the resin, which is particularly pleasant to touch. The polysiloxanes which are useful in the process of the invention are those of the formula (R₂SiO)_n, where R is preferably an alkyl, more preferably a linear alkyl, still more preferably a linear alkyl having 1 to 3 carbon atoms, dimethyl polysiloxane being particularly preferred. The polysiloxanes can also include functional groups, such as NH₂ or OH, which confer ionic properties.

According to a further embodiment of the invention, the water-based polyurethane mixture includes also a melamine-formaldehyde condensate. The presence of this condensate in the polyurethane aqueous mixture has been found to increase the adherence effect of the polymerized polyurethane film to the treated fabric.

The polyurethane mixture can further include catalysts to accelerate polymerization of polyurethane resin, thus shortening the processing time.

The thus treated fabric has a clear layer of polymerized polyurethane resin with a thickness varying as a function of the amount of mixture and pressure applied thereto and limited to the areas on which the mixture was applied.

According to a preferred embodiment of the invention, said polyurethane aqueous mixture further comprises a pigment or dyeing substance. The above mentioned dyeing substances include also the metallizing substances and pearlizing agents commonly used in textile industries .

Particul arly when said aqueous mixture contains anionic polyurethanes, anionic and non ionic pigments or dyeing substances are used , whereas when the mixture comprises cationic polyurethanes , cationic or non ionic pigments or dyes are used in the mixture .

Water dispersions of either organic or inorganic pigments and/or casein are particularly adapted. The above mentioned dispersions are advantageously admixed to the water mixture containing the polyurethane in a step immediately preceding the application in order to reduce the occurrence of stratification phenomena of the components. in carrying out this process, the water-based polyurethane mixture, either dispersion or emulsion of polyurethane in water, according to any one of the preceding embodiments, is applied onto the fabric preferably by air- or pressure-spraying. The aqueous mixture of polyurethane is sprayed in an amount of preferably 100 to 700 g/m² of fabric, more preferably in an amount of 200 to 400 g/m² of fabric.

Application by spraying, for example by spray gun, is particularly adapted to deposit on the fabric fibres a substantially continuous layer of polyurethane resin.

The applied polyurethane resin impregnates the fabric fibres and on drying provides a polymerized polyurethane layer strongly adherent to the fibres of the fabric.

After the application step, the still wet fabric is partially dried at a room temperature or under a hot air stream until it gives substantially no wet feeling on touching.

This condition preferably occurs when the amount of water soaking the fabric fibres is less than 10% by weight, more preferably less than 5% by weight, based on the weight of the fabric.

Advantageously the partial drying step is carried out for 20 minutes to 3 hours, if carried out at a room temperature. Once the initial step of drying is completed, the treated fabric undergoes a pressing step, preferably using a hot press.

Advantageously, the applied pressure is of 50 to 130 kg/cm², based on the kind of fibre of the fabric and the applied amount of resin.

According to a preferred embodiment, a press is used which is provided with a heating system, for example one having an electric resistance, in order to have a working temperature of 70 to 150°C, more preferably 90 to 110°C. During the pressing step, the polyurethane resin strongly binds to the fibres of the treated fabric for impregnating or soaking also those fibres layers which are not located at the surface of the fabric.

The energetic action of the press in addition to promoting the polyurethane-fabric packing, creates also a partial unravelling of the polyurethane fibres, thus giving a partial discontinuity among them.

Although the polyurethane resin layer creates a covering layer of the fabric fibres strongly adhering thereto, as a result of said unravelling, it preserves the perspiration properties of the fabric practically unchanged, near the treated areas.

After the pressing step, the fabric is then dried under temperature conditions in which the polyurethane resin reaches a high degree of polymerization.

By "high degree of polymerization" it is meant within the scope of the present invention that the polyurethane resin has reached a polymerization degree preferably greater that 80%. According to the preferred embodiment, the final step of drying is carried out in a desiccating oven or chamber wherein temperature is selected in the range of 100 to 200°C, more preferably 160 to 170°C.

Under these conditions (100° < T < 200°), the drying step allows a high degree of polymerization to be obtained in a span of time of 80 to 100 seconds, thus allowing an almost immediate storing and packaging of the fabric or of the treated clothing item.

The following examples are only illustrative and by no means limitative of the present invention.

EXAMPLE 1 A fabric of white cotton fibres was treated in accordance with the process of the invention by spraying with a air brush a water-base mixture comprising: ROLFLEX AP (water dispersion of anionic polyurethane) 1000 g

SOLSTIL S

( dimethyl polysiloxane in water emulsion) 100 g ROLAPRET MEL

(melamine-f ormaldehyde pre-condensate in water solution) 36 g

EXAMPLE 2 A used clothing item made of denim fabric was treated in accordance with the process of the invention by applying thereto by means of a spraying gun a water dispersion with the following components: ROLFLEX AP (water dispersion of anionic polyurethane) 800 g

ROLFLEX FSW

( f unctionalized polydimethyl siloxane in water emulsion) 200 g

CATALYST FSW

(polysiloxane in water emulsion) 100 g

EXAMPLE 3 A pair of trousers made of anthracite-coloured wool was treated in accordance with the process of the invention by brushing thereon a mixture consisting of: ROLFLEX AP (water dispersion of 30% anionic polyurethane ) 1000 g

SOLSTIL S

(dimethyl polysiloxane in water emulsion) 120 g

ROLAPRET MEL

(melamine-f ormaldehyde pre-condensate in water solution) 18 g

NERO ELETTA N/l - 130% (water dispersion of gas black) 0 . 5 g

All the components of the mixture which were used in examples 1-3 are manufactured by CESALPINA Chemicals S . p.A. in Arese (Milan; Italy ) .

EXAMPLE 4 Wate r di spe r s i on o f c at i oni c po lyurethane resin 1000 g metallized dye (Gold Standard Exagon by Coburn Corporation,

NJ, USA) 0.8 g

Advantageously, the plant for carrying out the process of the present invention is characterized in that it comprises a belt type conveyor along the upper active run of which a first station for positioning and securing clothing items and fabrics thereon, a second station for applying said mixture to said clothing items and fabrics, a third drying station, a fourth pressing station, a fifth calendering station, and a sixth and last station for desiccating said items and fabrics are provided in sequence.

In addition, the fabric obtained according to the above process and plant has its warp compenetrated by said mixture with the interposition of through holes. Brief description of the drawings

Further characteristics and advantages will clearly appear from the following detailed description of a preferred embodiment of a plant for carrying out the process for the organoleptic and surface modification of fabrics and clothing items, given only by way of illustrative and non-limitative example in the accompanying drawings, wherein: Figure 1 is a side schematic view of the plant of the invention;

Figure 2 is a front view of the modular calender forming part of the plant according to the invention; Figure 3 is another front view of a calender provided with a plurality of adjacent modular members, forming part of the plant according to the invention;

Figure 4 is an enlarged view of a natural fabric fibre coated with the mixture obtained according to the present process; and

Figure 5 shows a synthetic fibre coated with the mixture obtained according to the present process. Ways of carrying out the Invention

Referring to the above mentioned figures, the plant for carrying out the process for the organoleptic and surface modification of fabrics and clothing items is generally designated by the reference number 1.

Plant 1 substantially consists of a belt-type conveyor 2 along the upper active run 2a of which a first station 3 for positioning and securing clothing items and fabrics thereon, a second station 4 for applying said mixture to said fixed clothing items and fabrics, a third station 5 for partial drying, a fourth pressing station 6, a fifth calendering station 7, and a sixth and last station 8 for desiccating said items and fabrics are provided in sequence.

The second mixture application station 4 comprises a tank element 9 for containing the mixture prepared for the application process, which is connected to a means for atomizing and spraying said mixture towards the active run 2a of conveyor 2.

Said tank element 9 can be provided with a conventional member for continuously stirring the mixture, not shown for the sake of simplicity. The third station 5 for partial drying preferably consists of a tunnel or chamber 10 wherein the active run 2a is slidably arranged, said tunnel or chamber 10 being provided with the usual radiation and/or convection heating elements. The fourth pressing station 6 consists of frame for supporting a hammer 11 above said active run 2a and capable of vertical reciprocating movement and having also a thermal or heat means for contacting said clothing items and fabrics; said hammer 11 working together with a thrust bed 12 fixedly positioned below said active run 2a.

The fifth calendering station 7 comprises in turn a bridge-shaped frame 13 supporting at least a pair of transverse rollers 14 and 15 one overlaying the other and between which the articles of clothes and fabrics are nipped; the upper one of rollers 13 and 14 is rigid and can be heated, whereas the lower is resilient and has a lesser width than the upper roller.

Moreover, the first upper roller 13 is provided at the surface thereof with a plurality of grooves 16 adapted to allow the passage of protruding parts of the already made clothing items.

The sixth desiccating station 8 comprises a second tunnel 17 provided with conventional heating members, and within which active run 2a of conveyor 2 is slidably arranged. Finally, the fabric obtained by the process and plant

1, be it made of natural or synthetic fibres, has its warp compenetrated by said mixture with the interposition of through holes 18 which give said fabric a perspiration capability.

In practice, the working sequence for carrying out this process is as follows.

In the first station 3 the clothing items or the pieces of fabric to be treated are fixedly secured to the active run 2a of conveyor 2 which moves forwards stepwise.

At the subsequent station 4, the mixture prepared according to the process of the present invention and stored in tank element 9 is applied on the clothing item or the fabric preferably by atomized spraying. Afterwards, the thus treated clothing item or fabric passes through the third drying station 5, wherein only a partial drying is carried out in order to avoid the possible polymerization of the mixture components.

In the fourth pressing station 6, the clothing items or fabrics are pressed by hammer 11 which includes conventional heating elements and the action of which results in secure adherence of mixture to the fibres of the fabric.

If necessary, depending on its nature, the clothing item or fabric is passed to the subsequent calendering station 7 where rollers 14 and 15 are provided for an additional pressing action which is more precise and localized than the global action of hammer 11.

Particularly when ready-made clothes are treated, the protruding parts thereof, such as seams, buttons, etc. pass at grooves 16 so that they do not interfere with the action of said rollers 14 and 15.

It is to be noted that upper roller 14 has a rigid structure and a cross size slightly greater than that of roller 15 which has a flexible structure to prevent the fabric projecting therefrom from folding up towards the more rigid upper roller 14.

Finally, the clothing item or fabric is desiccated or completely dried within tunnel 17 of station 8, in practice, conveyor 2 moves said item or fabric trough said tunnel where it is exposed to a temperature of 165 °C for a time of 90 seconds.

It has thus been observed that the disclosed invention achieves the intended aim and objects. The invention thus conceived is susceptible of numerous modifications and variations all of which are within the scope of the inventive concept; thus, for example the various colours and decorations which can be applied may be chosen at will, according to the colour effects to be obtained.

All the details may further be substituted with other technically equivalent.

In the practical embodiment of the invention, the materials employed as well as the shapes and dimensions may be any according to requirements without thereby abandoning the scope of protection of the appended claims.

Claims

CLAIMS :

1. A process for the organoleptic and surface modification of fabrics and clothing items, comprising the steps of applying on a fabric an aqueous mixture comprising a polyurethane resin to obtain a treated fabric, partially drying the treated fabric, hot pressing, and further drying the treated fabric untill a high degree of polymerization of the applied polyurethane resin is obtained.

2. A process according to claim 1, wherein said aqueous mixture comprises an amount of polyurethane resin of 15 to 50% by weight.

3. A process according to claim 1, wherein said polyurethane resin is a polyether or polyamime resin.

4. A process according to claim 1 wherein said aqueous mixture further comprises a polysiloxane.

5. A process according to claim 1 wherein said aqueous mixture further comprises a melamine-formaldehyde condensate.

6. A process according to claim 1 wherein said aqueous mixture further comprises a dyeing pigment.

7. A process according to claim 1 wherein said aqueous mixture is applied by spraying in the amount of 100 to 700 g/m² of fabric.

8. A process according to claim 1 wherein said step of partially drying is carried out at room temperature for a time of 20 minutes to three hours.

9. A process according to claim 1 wherein said step of pressing the fabric is carried out at a pressure of 50 to 130 kg/m² and at a temperature of 70 to 150°C.

10. A process according to claim 1 wherein said step of further drying is carried out at a temperature of 100 to 200°C.

11. A process according to claim 10 wherein the further drying step is carried out at a temperature of 160 to 170 °C for a span of time of 80 to 100 seconds.

12. A plant for carrying out the process according to claim 1, comprising a belt type conveyor along an upper active run of which a first station for positioning and securing clothing items and fabrics thereon, a second station for applying said mixture to said clothing items and fabrics, a third drying station, a fourth pressing station, a fifth calendering station, and a sixth and terminal station for desiccating said items and fabrics, are provided in sequence.

13. A plant according to claim 12, wherein said second station for applying the mixture comprises a tank element for containing the mixture, said tank being connected to means for atomizing and spraying said mixture towards the conveyor active run.

14. A plant according to claim 13, wherein said tank element is provided with a member for continuously stirring the mixture.

15. A plant according to claim 12, wherein said third partial drying station comprises a tunnel/chamber wherein said active run is slidably arranged and is provided with radiation and/or convection heating elements.

16. A plant according to claim 15 wherein said heating members are adapted to keep the temperature inside said tunnel/chamber at the range of 30 to 50 °C.

17. A plant according to claim 12, wherein said fourth pressing station consists of a frame for supporting a hammer above said conveyor active run and capable of vertical reciprocating movement and provided with thermal or heat means for contacting said clothing items and fabrics, said hammer working together with a thrust bed fixedly positioned below said active run.

18. A plant according to claim 17 wherein said hammer is provided with thermo-insulating means adapted to prevent seizure thereof.

19. A plant according to claim 12 wherein said fifth calendering station comprises a bridge-shaped frame supporting at least a pair of transverse rollers one overlaying the other and between which the items of clothes and fabrics are nipped, the first and upper roller being rigid and adapted to be heated, and the second and lower roller being resilient.

20. A plant according to claim 19 wherein said lower roller has a lesser width than said upper roller.

21. A plant according to claim 19 wherein said first upper roller is provided at the surface thereof with a plurality of grooves to allow the passage of protruding parts of the clothing items.

22. A plant according to claim 12 wherein said sixth desiccating station comprises a second tunnel provided with heating members and in which the active run of said conveyor is slidably arranged.

23. A fabric obtained by a process according to claim 1 comprising a warp that is compenetrated by said mixture with interposition of through holes.

24. A fabric obtained by a process according to claim 1, the visible side of said fabric having a glossy and/or opaque plasticized aspect.

25. A fabric obtained by a plant according to claim 12 comprising a warp that is compenetrated by said mixture with interposition of through holes.