Textile product for removing excess colourants from washing waters

Abstract

 The present invention relates to a material for eliminating the colours released by laundry articles in the washing waters and optionally for removing scale, comprising a substrate of natural and/or synthetic fabric, natural and/or synthetic non-woven fabric, paper or felt and a "colour-fast" additive selected from polyaminoamidic resins with epichlorohydrin.

Description

[0001] The present invention relates to a material for eliminating excess colours in washing waters and optionally for the softening of the same, as well as a method for the production thereof.

[0002] It is known that "coloured" articles lose a certain amount of colour in the waters during the washing thereof; thus, in order to prevent other garments from being partly or even totally dyed, thus being damaged, they must be washed separately.

[0003] This problem is common to the housewives worldwide and has always been solved by accurately separating "coloured" articles from the so-called "white" ones, or using washing programs at low temperature, not always sufficient for an effective cleaning of the articles. On the other hand, the textile industry has attempted to manufacture articles the pigments thereof are as much as possible akin to the fabric, so as not to be massively released. In any case, wash after wash "white" articles unfortunately tend in any case to take a certain colouring, undesired by the consumer.

[0004] Materials are known that comprise a substrate whereon an additive is applied, capable of capturing the colour released by the darker articles, so that it is not transferred to lighter or "white" articles. However, such capability is sometimes insufficient for preventing the drawbacks mentioned above.

[0005] Therefore, there is the need for new materials which may be added to the laundry and would eliminate in a satisfactory manner the possibility that darker articles may dye the lighter ones.

[0006] Another problem that troubles the housewives and especially those living in areas wherein running water is "hard", is the forming of scale deposits on the inner surfaces of the washing machine.

[0007] The "hardness" of water is the amount of alkaline-earth metal salts, in particular bicarbonates, and calcium and magnesium sulfates, present in solution in the water, and it is measured in French degrees (°F). Water is defined as "medium hard" if it has a scale content (calcium carbonate) from 150 to 250 mg/l (15-25 ⁰F), whereas it is considered as "hard" if the scale content is higher than 250 mg/l (from 25 ⁰F).

[0008] As time goes by, waters that are medium hard or hard leave a deposit on the inner surfaces of the washing machines that is represented by a scale layer which, if not periodically removed, may cause the clogging of the water drains, the failure of washing machine components etc., with the consequent possible breakage of the appliance and/or large leaks of water.

[0009] In addition, as time goes by, the presence of a large amount of calcium and magnesium salts dissolved in the water causes damages to the washed articles. The negative consequences also affect the environment; in fact, calcium and magnesium salts are responsible for the partial neutralisation of the action of the detergents, which must therefore be used in larger amounts to obtain the cleaning action. It is therefore clear that a higher cost and greater pollution are thus determined. On the other hand, as regards the damages caused to the washed articles, these are due to the micro-deposit of scale into the fabric fibres, which causes a decrease of the softness thereof on the one side, and favours the early deterioration thereof on the other side.

[0010] Normally, in order to avoid the above problems, a suitable amount of an antiscaling agent, usually in the form of powder, tablet or liquid, may be added to the detergent, into the same tray.

[0011] The present invention, therefore, provides a material having improved properties, which surprisingly allows totally eliminating the colour present in the washing waters, thus preventing "white" articles from being dyed.

[0012] As a consequence, "coloured" and "white" garments may be washed at the same time into the washing machine in the presence of the material of the invention that behaves as "dye scavenger". Moreover, according to a further aspect, the material of the invention may further have a softening action on the water, so as to replace or integrate with the conventional antiscaling additives.

[0013] The present invention therefore relates to a material comprising a substrate and a suitable additive that adsorbs the colour, thus removing it from the washing waters, as described in the annexed claims.

[0014] In the other aspect of the invention, the material will additionally comprise an additive capable of softening the water, according to what is reported in the claims.

[0015] As regards the substrate, it may comprise any material compatible with the normal laundry and it may have any shape and dimension such as for example, a tissue or a fabric cloth. Preferably, the substrate has the shape of a tissue.

[0016] Typically, the substrate is a natural and/or synthetic fabric, a natural and/or synthetic non-woven fabric or paper or felt, for example needled felt.

[0017] In one embodiment, the substrate is a natural and/or synthetic non-woven fabric, more preferably it is a synthetic non-woven fabric.

[0018] Non-woven fabrics that may conveniently be used are: spunlaced, spunbonded, thermobonded, airlaid or felt.

[0019] Moreover, the material of the substrate may be smooth, pierced, embossed or needle-punched.

[0020] The terms spunlaced, spunbonded, thermobonded, airlaided and needle-punched indicate both non-woven fabrics and the techniques used for obtaining them, well known in the art. The fibres preferably used for obtaining these non-woven fabrics are fibres of: polyester (PE), polypropylene (PP), polylatex (PLA), polyethylensulfone (PES), acrylic polymers, regenerated cellulose, for example lyocell® (that is, regenerated cellulose fibre, obtained by a process of dissolving and spinning in an organic solvent) or tencell® cotton, viscose or mixtures thereof. Preferably, the substrate is 80% regenerated cellulose, for example: lyocell® or tencell® or viscose.

[0021] According to an aspect of the invention, the substrate is 80% regenerated cellulose or viscose, obtained by the spunlace technique, whereas according to a further aspect it is needled felt, 80% regenerated cellulose or viscose.

[0022] The substrate therefore has the function of "carrier", that is, of support for both the additive that removes the colour and for any water softening additive, when provided.

[0023] In the present invention it has been surprisingly found that a polyaminoamidic resin with epichlorohydrin is capable of removing the colour released by "coloured" articles from the washing waters, thanks to the high affinity for the dyes. In fact, one of the principles at the basis of this invention is that the dye released in the washing waters by "coloured" articles has a much higher affinity for the material of the present invention than for the "white" fabrics present in the laundry.

[0024] More in particular, the additive capable of capturing the colour is an aqueous solution of a polyamide cationic resin comprising 15-25% of a copolymer of adipic acid with chloromethyloxirane, diethylenetriamine and epichlorohydrin (CAS 25212-19-5).

[0025] Preferably, said additive corresponds to that provided by EIGENMANN & VERONELLI by the name of HERCOSETT 250 LX.

[0026] The additive that removes the colour may advantageously be prepared in aqueous solution.

[0027] This solution is especially suitable for the application of the additive with techniques used in the field of dyeing.

[0028] The substrate preferably has a weight comprised between 50 g/m² and 250 g/m², more preferably between 60 g/m² and 100 g/m².

[0029] More in particular, when a spunlace material is used, the weight is preferably comprised between 50-100 g/m², whereas if the substrate is made of felt, this preferably has a weight comprised between 100-250 g/m².

[0030] The substrate fibres preferably have dimensions comprised between 0.5 dtex and 5 dtex, preferably between 1 dtex and 3 dtex.

[0031] According to the other aspect of the present invention, the additive for sequestering calcium and magnesium ions, and therefore softening the washing waters, is a compound comprising a product selected from polyacrylate, polyphosphonate and a salt of EDTA (ethylenediaminetetraacetic acid). The sequestrant, for example, is used in an amount designed for leaving a weight on the support comprised between 5 and 100 g/m² referred to the dry substrate, preferably between 7 and 50 g/m², more preferably about 10 g/m².

[0032] To make the sequestering additive applicable to the non-woven substrate, for example through a silk-screen printing process, the compound also comprises an acrylic or natural polyurethane thickener. The thickener may further be used in amounts comprised between 5% and 100% relative to the amount of sequestrant, preferably between 20% and 80%, more preferably about 50%. Of course, amount and specific type of thickener shall be selected by the man skilled in the art according to the type of application, to the machine settings and to the selected substrate. The preferred natural thickener is Guaro flour IDALCA by the company Lamberti Spa.

[0033] If it is chosen to use the sequestrant in combination with the thickener, a viscous compounds is obtained, as said, which may preferably be stabilised with a dispersant, for example acrylic-based. The amount used of such substance may be comprised between 5% and 50% relative to the amount of sequestrant product, preferably between 7% and 20% and more preferably about 10%.

[0034] According to a further aspect of the invention, the compound may comprise a substance called "false dye". From the technical point of view, it is a dye defined as "direct blocked", that is, a substance that colours the substrate but that cannot steadily fix onto any fabric. In use, the "false dye" dissolves in the washing waters without interfering with the laundry or with the product of the invention. In particular, the compound having softening properties is substantially colourless. The use of a "false dye" advantageously allows imparting a colour to the softening compound when this is applied (by printing) onto the substrate, which is white coloured, for example for highlighting the logo of the manufacturing company or a fantasy trademark or any other pattern or symbol as desired. When the substrate is immersed in the washing waters, the softening compound thus tends to slowly dissolve during the entire washing cycle; at the same time, the surface of the surrounding substrate almost instantaneously takes on a colour due to the effect of the dye scavenger substance. As a result, the non-woven substrate becomes coloured by the effect of the capture of the colour released by the laundry articles in the washing water, with the exception of the points whereon the softening compound has been applied. In fact, the negative pattern/logo pattern will remain at such points. In other words, the colour released by the coloured articles is immediately captured by the substrate, which is white and therefore becomes coloured thanks to the dye scavenger substance, whereas the softener, coloured and only applied in some points of the substrate, slowly dissolves leaving the underlying white substrate visible.

[0035] In addition, the softening compound may comprise a binder. The binder is any substance capable of cohesing the substrate of non-woven fabric. In fact, the binder allows strengthening the substrate structure to prevent the washing cycles from damaging it. In particular, modern washing machines have washing, but above all spinning cycles, that are very strong and therefore they subject the material of the present invention to a great wear. This may cause a quick deterioration of the substrate in general and in particular of a spunlaced substrate, which represents one of the preferred aspects of the invention for versatility, softness, feeling and binding power of the colours. Otherwise, in fact, the spunlaced substrate may lint, releasing fibres to the washing water that would attach to the garments, with imaginable consequences.

[0036] As regards the nature of the binder, this may be a resin such as for example an acrylic, vinyl, polyurethane resin or a natural resin. The binder may also be a latex, natural or synthetic. The amount of use of the binder (also called bonder) may range from 5% to 100% of the sequestrant product, preferably between 7 and 50% and more preferably it is about 10%.

[0037] According to another object, the invention relates to the preparation of a "colour-fast" material having improved properties.

[0038] In particular, after having prepared the "colour-fast" agent-based compound in a suitable solution or in composition with the further ingredients mentioned above as described above, said compound is applied onto the non-woven substrate through application methods known in the field, such as for example impregnation, spreading or printing, as shall be detailed hereinafter.

[0039] The product object of the present invention may be obtained by combining, in any way, one of the substrates listed above with the colour-fast additive of the invention.

[0040] More in particular, the preferred finished product comprises the substrate whereto the polyamide cationic resin with epichlorohydrin described above is applied.

[0041] According to optional aspects, the material of the invention may also comprise an additive for sequestering the salts of alkaline-earth metals, in particular bicarbonates and calcium and magnesium sulfates, for example polyacrylic, polyphosphonate or a salt of EDTA, having the function of softening the water.

[0042] As mentioned above, in another aspect the present invention relates to a process for manufacturing the product object of the invention.

[0043] Said process comprises the following steps:

a) providing a substrate comprising one among the following materials: natural and/or synthetic fabric, natural and/or synthetic non-woven fabric, paper or felt;

b) treating the substrate with the colour-fast additive described above;

c) eliminating any excess colour-fast additive;

d) drying the substrate.
Optionally, according to the further aspects of the invention, such process may comprise the additional steps of:

e) applying onto the semi-worked substrate obtained in step d) a compound comprising at least one sequestrant of calcium and magnesium ions selected among polyacrylate, polyphosphonate and a salt of EDTA;

f) drying the substrate, so as to obtain the end product.

[0044] Steps b), c), d) and f) are preferably carried out through impregnation, spraying, printing and/or plating techniques, which are all techniques known in the art. Preferably, the colour-fast additive is applied by impregnation.

[0045] The relation that sets between additive and substrate may be: absorption, adsorption, hydrogen bond, electrostatic forces, for example ion/ion or ion/dipole interactions, chemical or physical bond, etc.

[0046] Advantageously, the working speeds according to the process of the invention are comprised between 11 and 30 m/min in the case of a substrate of needled felt, whereas if a spunlaced substrate is used, the speeds may be 11-50 m/min.

[0047] Step e) may be carried out through any method known in the field such as for example impregnation, spreading and printing. The preferred method is printing and in particular, silk-screen printing.

[0048] For silk-screen printing, a thick mixture is prepared comprising the sequestrant, the thickener and optionally the false dye, as explained above.

[0049] In step e) the thick mixture, prepared for example as described above, may be applied by printing on the substrate coming from the drying step d), preferably by silk-screen printing.

[0050] The quantity of dense mixture that is applied to the substrate is comprised between 1 and 100 g/m² referred to the substrate, preferably between 20 and 80 g/m², even more preferably about 70 g/m².

[0051] The amount of dense mixture and therefore of sequestrant additive that may be applied to the substrate must be a proper balance between a too low amount, which would have poor activity, and a too high amount which would be very active but would partly interfere with the activity of the colour-fast additive. Different amounts may also be provided according to the hardness level of the water with which the product of the invention is intended to be used.

[0052] In step f) the substrate is dried at a temperature from 40°C and not higher than 110°C, preferably about 100°C.

[0053] Steps a)-d) are preferably carried out continuously, that is, the substrate is subject to impregnation, squeezing and drying without intermediate steps or stops (optionally for allowing the additive to better bind with the substrate) between each treatment. This is possible since the additive exhibits a high affinity for the substrate and thus, the desired amount of additive binds almost instantaneously to the substrate and leaving the substrate in impregnation for a long time is not required.

[0054] After the drying step d), the semi-worked substrate may be rolled and moved to another machine where it shall be unrolled and subject to steps e) and f). As an alternative, the semi-worked substrate of step d) is not rolled but immediately sent to printing (step e)), then to drying (step f)) and then, rolled. In other words, the manufacturing process may be carried out continuously with a single machine, from step a) to step f), or in "batches" carrying out steps a)-d) with one machine and steps e)-f) with a second machine.

[0055] The product of the present invention is normally inserted in conventional or professional washing machines prior to starting the washing cycle along with "white" and "coloured" articles.

[0056] "White" articles are those articles having white fabrics and/or light coloured fabrics (for example: beige, pink, light blue, grey etc.); preferably, therefore, light coloured fabrics.

[0057] "Coloured" articles are those articles having dark (for example: red, burgundy, yellow etc.) or very dark (for example: blue, black, dark green, jeans etc.) coloured fabrics. These fabrics may already have been subject to washing in washing machine or not. Preferably, "coloured" articles denote laundry comprising dark coloured fabrics (for example: red, burgundy, yellow, orange, etc.); more preferably, it denotes dark coloured fabrics already subject to 5 or 6 washings.

[0058] When the washing starts, the thickener dissolves in water releasing the sequestrant and the false dye. The sequestrant dissolved in water thus carries out its function of capturing the calcium and magnesium ions preventing the deposition thereof, such as carbonates and sulfates, on the inner walls of the washing machine. The false dye disperses in the washing water but without dying the garments and is eliminated with the subsequent rinsing along with the sequestrant bound to calcium and magnesium ions. Therefore, the only purpose of the false dye is to make the printed compound visible, as commercial medium and at the same time a system for controlling the operation. The colour-fast additive remains anchored to the substrate and carries out its function having a higher affinity for the pigments present in the washing waters than the affinity existing between the pigments and the fabrics of "white" articles.

[0059] Ideally, the material of the invention is inserted in the washing machine along with light coloured fabrics and dark coloured fabrics already washed 5 or 6 times before. The number of sheets of the material of the invention that are used for each washing depends on the laundry weight, on the colours of the articles and on the water hardness. Preferably, 2 or more sheets of material of the invention are inserted in the washing machine if there are fabrics that lose a large amount of colour, for example cotton fabrics with deep colour hues and in the presence of hard water.

[0060] The material of the invention withstands the normal washing temperatures and the common detergents and additives, as well as bleach.

ADVANTAGES

[0061] The combined action of the substrate and of the pigment, which both have a high affinity for pigments, allows obtaining a much higher efficiency in retaining the colour present in the washing waters than the products of the prior art.

[0062] Moreover, when provided, the dual function of "colour-fast" and "scale capture" that the product exhibits according to an optional aspect of the invention, is very advantageous. In fact, the dual effect of preventing "white" articles from being dyed subsequent to the loss of colour by darker articles, and the deposit of salts onto the articles and within the washing machine is obtained with a single action, preserving the proper operation thereof.

[0063] This leads to a high usage convenience, especially for people that have little time to dedicate to housework which, in this way, can wash "white" and "coloured" articles together.

[0064] Moreover, if the combination of the colour-fast additive with the antiscaling additive is provided, it is not necessary anymore to worry and above all remember adding such additive prior to the washing. In fact, it has been experimentally proven that the product of the invention, if used regularly, has the same antiscaling efficacy as the conventional additives that are not combined with other additives, as the colour-fast one.

[0065] The process of the invention is very fast since it may be carried out continuously and has a limited number of steps. This implies a considerable saving of time and energy. In fact, the end material is obtained in times in the order of minutes since the "colour-fast" additive binds to the substrate almost instantaneously and it is not necessary to leave it resting for hours to make the additive be absorbed onto the substrate, as in the processes of the prior art. All of this is possible thanks to the use of the "colour-fast" additive of the present invention which exhibits a very high affinity for the substrate and is absorbed in effective amount almost instantaneously. Moreover, the subsequent printing and drying steps are also very fast.

[0066] One of the particular preferred combinations, that is, between a needled felt substrate and the colour-fast additive of the invention is the one that has allowed obtaining the best results in terms of resistance to the usage and efficiency conditions.

[0067] Experimental tests have been conducted using different substrates according to the present invention, whereto the colour-fast additive described above has been applied.

[0068] In particular, the tests were based on the reading of the difference of ΔE of colour of a single-fibre sample cotton fabric (Empa221) and of a multi-fibre fabric (Empa 410), subsequent to a washing in Linitest in the presence of a fading red cloth and of direct dyes (Tiasol Blue and Red + Empa Red).

[0069] The lower the value of ΔE the better the colour-fasting property of the product.

[0070] In the practice, the tests simulate what occurs in the washing bath, using an amount of fabrics and of detergent proportioned to a washing bath of 10 litres (washing step only) in washing machine.

[0071] The following products were used:

a) Product according to patent application MI2006A000096.

b) Product according to the present invention - felt

c) Product according to the present invention - Spunlaced.

[0072] The 8-station Linitest, one Minolta spectrophotometer and a two decimal digit technical scale with ±0.01 g accuracy were used for the tests. The temperature was 40°C using the Omino Bianco Lavatrice Marsiglia detergent.

[0073] Averaging the results of the colour-fast properties obtained at the Linitest on the various fabrics and at different conditions (Figures 1-4) it is seen that the product of the invention has surprising properties in capturing the colour released by the coloured articles during the washing.

Claims

1. "Colour-fast" material comprising a substrate selected among the group consisting of natural and/or synthetic fabric, natural and/or synthetic non-woven fabric, paper and felt and as "colour-fast" additive a polyamide cationic resin comprising a copolymer of adipic acid with chloromethyloxirane, diethylenetriamine and epichlorohydrin.

2. The "colour-fast" material according to claim 1, further comprising an additive for sequestering calcium and magnesium ions selected among: polyacrylate, polyphosphonate and a salt of EDTA.

3. Material according to claim 1 or 2, wherein said substrate is a spunlaced, spunbonded, thermobonded, airlaided non-woven fabric or needled felt.

4. Material according to claim 1, 2 or 3, wherein said substrate is made from viscose, polypropylene, polyester, cotton or cellulose pulp.

5. Material according to one of claims from 1 to 4, wherein the substrate is a synthetic spunlaced, spunbonded, thermobonded, airlaided non-woven fabric or needled felt.

6. Material according to any one of claims from 1 to 5, wherein said substrate is spunlaced non-woven fabric, 80% regenerated cellulose or viscose.

7. Material according to claim 1, wherein said substrate is made from felt, 80% regenerated cellulose or viscose.

8. Material according to claim 7 having a weight of between 100-250 g/m².

9. Material according to any one of claims 1 to 6, wherein said substrate has a weight of between 50 g/m² and 100 g/m².

10. Material according to any one of claims 1 to 9, wherein said colour-fast additive is HERCOSETT 250 LX.

11. Material according to any one of claims 2 to 10, wherein said additive for sequestering calcium and magnesium ions is a salt of EDTA or a polyacrylate polymer present in an quantity of between 5 and 100 g/m² of dry substrate.

12. Material according to any one of claims 1 to 11, further comprising a natural or polyurethane thickener.

13. Material according to claim 12, wherein said natural thickener is Guaro flour.

14. Material according to claim 12 or 13, further comprising a dispersant, preferably acrylic-based.

15. Material according to claim 14, wherein said dispersant is present in a quantity of between 5% and 50% with respect to the quantity of sequestrant.

16. Material according to any one of claims 1 to 15, further comprising a false dye.

17. Material according to any one of claims 1 to 1.6, further comprising a binder capable of cohesing the substrate of non-woven fabric.

18. Material according to claim 12, wherein said thickener is selected among acrylic, polyurethane vinyl or natural resin present in a quantity of between 5% and 100% with respect to the quantity of sequestering agent.

19. Process for the production of a "colour-fast" material comprising the following steps:

a) providing a substrate selected among the group consisting of: natural and/or synthetic fabric, natural and/or synthetic non-woven fabric, paper and felt;

b) treating the substrate with the additive according to claim 1 or 10;

c) eliminating the excess additive, and

d) drying the substrate.

20. Process according to claim 19, wherein, in step b), the substrate is treated through impregnation, spraying, printing and/or plating.

21. Process according to claim 20, wherein, in step b) in the case in which the impregnation technique is used, the substrate is treated with a solution of the colour-fast additive.

22. Process according to claim 21, wherein said additive solution is an aqueous solution.

23. Process according to any one of claims 19 to 22, wherein the concentration of additive is comprised between 0.5% and 100%, preferably between 0.5% and 4%.

24. Process according to any one of claims 19 to 23, wherein in step c) the excess additive is removed by making the substrate pass through two or more rollers.

25. Process according to any one of claims 19 to 24, wherein, in step d), the substrate is dried in a oven at a temperature of between 40°C and 110°C.

26. Process according to any one of claims 19 to 25, wherein, in step d), the substrate is dried for a time of between 1 and 5 minutes, preferably about 3 minutes.

27. Process according to any one of claims 19 to 26, further comprising the steps of:

e) applying onto the semi-worked substrate obtained in step d) a dense mixture comprising at least one sequestrant of calcium or magnesium ions selected among polyacrylate, polyphosphonate and a salt of EDTA;

f) drying the substrate, so as to obtain the end product.

28. Process according to any one of claims 19 to 27, wherein, in step e), the printing takes place with the silk-screen printing technique.

29. Process according to any one of claims 27 or 28, wherein the quantity of dense mixture that is applied to the substrate is comprised between 1 and 100 g/m², preferably between 20 and 80 g/m², even more preferably about 70 g/m².

30. Process according to any one of claims 19 to 29, wherein, in said step f), the drying occurs at a temperature of less than 110°C, preferably less than 100°C.

31. Process according to any one of claims 19 to 30 that is carried out continuously.

32. Material obtainable through the process according to any one of claims 19 to 31.

33. Use of the material according to any one of claims 1 to 18 to remove the colour present in laundry water and to sequester the calcium and magnesium ions.

34. Method for removing the colour and the limestone from laundry water with the material according to any one of claims 1 to 18 comprising the following steps:

- providing an averagely hard or hard water bath containing laundry of various colours;

- including in the bath the material according to any one of claims 1 to 18;

- leaving said material in said bath for an entire washing cycle in the washing machine at the end of which said material and said laundry are separated with the result that said material has captured all of the colour present in the washing water and the limestone sequestrant has been released into the washing water obtaining a softening effect.

35. Method according to claim 34, wherein the steps are repeated many times in the presence of the same material.

Drawing