EP3077490A1

EP3077490A1 - Cleaning additives in the form of a sheet

Info

Publication number: EP3077490A1
Application number: EP14802655.2A
Authority: EP
Inventors: Patrick Mcnamee; Lauriane LE GUERLÉDAN
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 2013-12-03
Filing date: 2014-11-25
Publication date: 2016-10-12
Also published as: GB2520935A; GB201321279D0; GB2520935B; WO2015082251A1

Abstract

A laundry sheet comprising a non-woven substrate impregnated with an optical brightener and/or a first anti-soil re-deposition agent is disclosed. Examples of the non-woven substrate are wet-laid, spun lace, spun bond, needle punch or air laid. The optical brightener can be, for example, Disodium 2,2'-([1,1'-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate). The anti-soil re-deposition agent can be, for example, polyvinylpyrrolidone. In addition, the substrate can additionally be impregnated with a pigment such as copper phthalocyanine. In addition, the substrate can additionally be impregnated with a second anti-soil re-deposition agent such as modified polyester co-polymer.

Description

CLEANING ADDITIVES IN THE FORM OF A SHEET

This invention relates to improvements in or relating to clothes washing. Detergents of varying types have been on the market for many years. Over that period of time, the washing ability of detergents has been improving not only from the perspective of cleaning clothes but also from the perspective of providing additives which can have an effect on the clothes other than a cleaning effect. In addition, with the need to reduce energy costs, detergents are now being produced which can have the same or a better cleaning effect at temperatures 50° C or below even down to so called "cold wash" where the water temperature can be as low as 20° C as compared with their earlier counterparts which required that clothes be washed at relatively high temperatures generally around 60° C.

In addition, the consumer is also aware of the need to obtain his/her perceived value for money in that detergents which are sold by what can be regarded as the brand leaders are relatively expensive compared with so-called own brand products. It is well known that consumers can regard some detergents, which are perceived to be less expensive, as not performing as well as the more expensive brands. Thus, detergent manufacturers have to strike a balance between producing product which is less expensive than the so called more expensive leading brands and the consumer's perception of quality. In order to maintain the same or equivalent cleaning power, particularly at relatively low temperature washing cycles, the comparatively lower cost detergents are less expensive because, quite often, they do not contain certain additives which are not essential for successful washing of the clothes but are desirable. Such additives include, but are not limited to, chemicals which will impart a perfume on the washed clothes; or will comprise so-called whiteners which will provide the consumer with the experience that, in particular, white garments are not only clean but appear sparkling white; or anti-soil re-deposition agents to prevent unwanted matter in the laundry wash from being absorbed, reabsorbed or deposited on the clothes.

It is well known among detergent manufacturers that many consumers desire that their laundry is not only washed but is seen to be washed by virtue of the relative whiteness of, for example, white articles.

From a consumer perspective, it is desired in many instances to purchase a relatively less expensive detergent but, where the occasion demands, to be able to enhance to the effects of the less expensive detergent by adding the desired chemicals derived from a sheet which is impregnated with the desired chemical(s).

According to an aspect of the present invention, there is provided a laundry sheet comprising a non- woven substrate with an optical brightener and/or a first anti-soil re-deposition agent impregnated thereon. According to another aspect of the present invention, the substrate is additionally impregnated with a pigment and, preferably, wherein the pigment is copper phthalocyanine.

According to another aspect of the present invention, the substrate is impregnated with a second anti-soil re-deposition agent.

Examples of a non-woven substrate are non-woven constructions such as wet-laid, spun lace, spun bond, needle punch or air laid. Examples of a wet laid non-woven construction are viscose fibres and/or pulp fibres. Examples of spun lace non-woven constructions are cellulosic fibres and/or hydrophilic synthetic fibres. Examples of a spun bond non-woven construction are polypropylene spun bond hydrophilic fibres and/or polyester fibres. Examples of a needle punch non-woven constructions are cellulosic fibres and/or hydrophilic synthetic fibres. Examples of air laid non-woven constructions are viscose fibres and/or pulp fibres. According to another aspect of the present invention, the optical brightener is Disodium 2,2'-([1 , 1 '- biphenyl]-4,4'-diyldivinylene)bis(benzenesulphonate) (DSBP); the first anti-soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP); and the second anti-soil re-deposition agent is in the form of a modified polyester co-polymer. According to another aspect of the present invention, the substrate is present in an amount of from about 69.1 % to about 91 .6%, optionally from about 69.1 % to about 90.85%, further optionally about 82.83%; the optical brightener is Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and is present in an amount of from about 4.5% to about 17.4%; the first anti-soil re-deposition agent is polyvinylpyrrolidone (PVP) and is present in an amount of from about 4.5% to about 17.4%; and the pigment is a copper phthalocyanine pigment and is present in an amount of from about 0.15% to about 1.45%, the percentages being % by weight of the sheet.

According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic and comprises about 82.83%; the optical brightener is in the form of Disodium 2,2'-([1 , 1 '- biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and comprises about 9.54%; the first anti-soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP) and comprises about 7.34%; and the pigment is in the form of a copper phthalocyanine and comprises about 0.29%, the percentages being % by weight of the sheet.

According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic and comprises about 82.83%; the optical brightener is in the form of Disodium 2,2'-([1 , 1 '- biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) comprises about 7.34%; the first anti- soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP) and comprises about 9.54%; and the pigment is in the form of a copper phthalocyanine and comprises about 0.29%, the percentages being % by weight of the sheet. According to another aspect of the present invention, the substrate is in the form of a polypropylene spunbond hydrophilic and is present in an amount from about 67.9% to about 89.3%; the optical brightener is in the form of Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'-diyldivinylene)bis(benzenesulphonate) (DSBP) and is present in an amount from about 3.6% to about 1 1.2%; the first anti-soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP) and is present in an amount from about 4.7% to about 14.6%; the pigment is in the form of a copper phthalocyanine and is present in an amount from about 0.14% to about 1.4% and the second anti-soil re-deposition agent is in the form of a modified polyester co-polymer and is present in an amount from about 2.0% to about 6.1 %, the percentages being % by weight of the sheet.

According to another aspect of the present invention, the substrate is in the form of a polypropylene spunbond hydrophilic substrate and comprises about 79.66%; the optical brightener is in the form of Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'-diyldivinylene)bis(benzenesulphonate) (DSBP) and comprises about 7.06%; the first anti-soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP) and comprises about 9.18%; the pigment is in the form of a copper phthalocyanine and comprises about 0.28%; and the second anti-soil re-deposition agent is in the form of a modified polyester co-polymer and comprises about 3.82%, the percentages being % by weight of the sheet.

According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic substrate and is present in an amount from about 67.9% to about 89.3%; the optical brightener is in the form of Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and is present in an amount from about 3.6% to about 1 1.2%; the first anti-soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP) and is present in an amount from about 4.7% to about 14.6%; and further comprises a pigment and a second anti-soil re-deposition agent; wherein the pigment is copper phthalocyanine and is present in an amount from about 0.01 % to about 1.4% and the second anti-soil re-deposition agent is in the form of a modified polyester co-polymer and is present in an amount from about 2.0% to about 6.1 %, the percentages being % by weight of the sheet.

According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic substrate and comprises about 79.86% by weight; the optical brightener comprises about 7.08%; the first anti-soil re-deposition agent comprises about 9.20%; the pigment comprises about 0.04%; and the second anti-soil re-deposition agent comprises about 3.82%, the percentages being % by weight of the sheet.

According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic and is present in an amount of from about 91.9% to about 98.1 %; the optical brightener is Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'-diyldivinylene)bis(benzenesulphonate) (DSBP) and is present in an amount of from about 1.7% to about 6.6%; and the pigment is copper phthalocyanine and is present in an amount of from about 0.17% to about 1.71 %, the percentages being % by weight of the sheet.

According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic and comprises about 95.43%; the optical brightener is in the form of Disodium 2,2'-([1 , 1 '- biphenyl]-4,4'-diyldivinylene)bis(benzenesulphonate) (DSBP) and comprises about 4.23%; and the pigment is copper phthalocyanine and comprises about 0.34%, the percentages being % by weight of the sheet. According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic and is present in an amount of from about 79.0% to about 98.3%; the first anti-soil re- deposition agent is polyvinylpyrrolidone (PVP) and is present in an amount of from about 1.7% to about 21.0%, the percentages being % by weight of the sheet. According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic and comprises about 89.67%; the first anti-soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP) and comprises about 10.33%, the percentages being % by weight of the sheet. According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic and is present in an amount of from about 93.3% to about 98.3%; the optical brightener is Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'-diyldivinylene)bis(benzenesulphonate) (DSBP) and is present in an amount of from about 1.7% to about 6.7%, the percentages being % by weight of the sheet. According to another aspect of the present invention, the substrate is a polypropylene spunbond hydrophilic and comprises about 95.76%; the optical brightener is in the form of Disodium 2,2'-([1 , 1 '- biphenyl]-4,4'-diyldivinylene)bis(benzenesulphonate) (DSBP) and comprises about 4.24%, the percentages being % by weight of the sheet. In order to provide the sheet, a liquid composition is provided which can be impregnated onto the sheet.

The liquid composition can comprise water and polyvinylpyrrolidone (PVP) and wherein the water is present in an amount of from about 85.0% to about 99.0%; and PVP is present in an amount of from about 1.0% to about 15.0%, the percentages being % by weight of the composition.

Preferably, the water is present in an amount of about 93.5%; and PVP is present in an amount of about 6.5%, the percentages being % by weight of the composition. The liquid composition can comprise water and Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and wherein the water is present in an amount of from about 96.0% to about 99.0%; and DSPB is present in an amount of from about 1.0% to about 4.0%, the percentages being % by weight of the composition.

Preferably, the water is present in an amount of about 97.5%; and DSPB is present in an amount of about 2.5%, the percentages being % by weight of the composition.

The liquid composition can comprise water, polyvinylpyrrolidone (PVP) and Disodium 2,2'-([1 , 1 '- biphenyl]-4,4'-diyldivinylene)bis(benzenesulphonate) (DSBP) and wherein the water is present in an amount of from about 75% to about 95%; PVP is present in an amount from about 2.8% to about 14.1 %; and DSPB is present in an amount of from about 2.2% to about 10.9%, the percentages being % by weight of the composition.

Preferably, the water is present in an amount of about 88.5%; PVP is present in an amount of about 6.5%; and DSPB is present in an amount of about 5.0% by weight, the percentages being % by weight of the composition.

A suitable version of PVP known as PVP K-30 (CAS No. 9003-39-8) is available from Ashland of Covington KY 4101 1 USA and is presented as an amorphous powder. A suitable DSBP is sold by BASF of Ludwigshafen, Germany under the brand name Tinopal® CBS- X.

The PVP K-30 in use acts as an anti-soil re-deposition agent while the DSPB in use functions as an optical brightening agent. In addition when present, the PVP serves to bind the reagents to the substrate.

It would also be possible to incorporate a second anti-soil re-deposition agent in the form of a modified polyester co-polymer in addition to the PVP. An example of such an agent is Hydroperm SRHA liq. available from Clariant of CH-4132 Muttenz, Switzerland.

The liquid composition can comprise water in an amount of from about 60% to about 90% ; PVP in an amount of from about 3.0% to about 12.1 %; DSPB in an amount of from about 2.3% to about 9.3%; and the modified polyester co-polymer in an amount of from about 4.7% to about 18.6%, the percentages being % by weight of the liquid composition.

Preferably, the water is present in an amount of about 78.5%; the PVP is present in an amount of about 6.5%; DSPB is present in an amount of about 5.0%; and the modified polyester co-polymer is present in an amount of about 10%, the percentages being % by weight of the liquid composition. When preparing the liquid composition, it is important that initially, the PVP is added to water (or is available as an aqueous solution) followed by the DSPB so as to avoid the latter from clumping or forming aggregates in the solution which is not desirable. If desired, the liquid composition can also comprise a pigment an example of which is a Copper phthalocyanine pigment sold under the brand name of Tinolux® BBS (CAS No. 131595-16-9) and available from BASF. When used in any of the compositions, the pigment is optionally present in the range of from about 0.01 % to about 1.0%, preferably about 0.05%; or from about 0.1 % to about 1.0%, preferably about 0.2%; with the percentage of water adjusted accordingly, the percentages being % by weight of the composition.

In preparing the liquid composition, the first step is to mix water and polyvinylpyrrolidone (PVP) (if present) and, as a second step, add Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP).

If desired, the pigment such as a copper phthalocyanine can be added after the second step.

If desired, the modified polyester co-polymer can be added after the second step. An example of a copper phthalocyanine pigment is sold under the brand name of Tinolux® BBS (CAS No. 131595-16-9) and which is available from BASF.

A suitable example of the polypropylene spunbond hydrophilic substrate is available from Don & Low Ltd Nonwovens of Angus, Scotland and sold under the brand name of Daltex ® Hydrophilic

Nonwoven which is a polypropylene nonwoven spunbond containing a hydrophilic treatment.

The preferred weight of the sheet is 50g.m² (gsm) but sheets having weights of from 45g.m² - 100 g.m² can be used. The preferred size of the sheet for use by the consumer will be approximately 245mm x 1 15mm having a weight of 50 g.m², but it will be appreciated that any suitable size sheet can be used.

It will be appreciated that the sheet may comprise the substrate together with the PVP, the DSPB and the pigment. Alternatively, the sheet could comprise the substrate and the PVP only; the substrate and the DSPB only; or the substrate and the PVP and the DSPB. Clearly, when the sheet comprises just the substrate and the PVP only, it has an anti-soil re-deposition effect in the wash. Where the sheet comprises the substrate and the DSPB only, it has an optical brightener effect in the wash. Where the sheet comprises the substrate with the PVP and the DSPB, it has an anti-soil re-deposition effect and an optical brightener effect in the wash. To provide an enhanced anti-soil re- deposition effect, any of the above combination can incorporate a second anti-soil re-deposition agent in the form of Hydroperm SRHA liq. The purpose of the pigment is to provide a visible colour to the sheet and can be present if the sheet comprises any of the combinations referred to above. However, in the wash, the pigment passes from the sheet into the wash water thereby resulting in a white sheet when removed from the wash. This serves to provide to the user an indicator of the effectiveness of the sheet in use. It will be appreciated that, because a pigment is used rather than a dye, any clothes susceptible to undesirable uptake of a dye will not be affected by the presence of the pigment as clothes which are susceptible to extraneous dye uptake will not be affected in this manner if a pigment is used. Whatever the composition of the sheet, the chemicals present on the substrate are referred to as actives.

It is important that the substrate is hydrophilic rather than hydrophobic as the latter would not permit the actives to be absorbed on to the substrate in the desired quantity and, thereafter, liberated therefrom in the wash liquor in order to achieve the desired effect(s). In addition, the substrate should be able to absorb and carry between about 2.0g and about 3.0g, preferably about 2.5g of active(s) per sheet.

When the dry sheet comes into contact with the water in the wash liquor, all of the actives are liberated from the sheet. In the case of the PVP and/or the Hydroperm SRHA liq. (which serve to prevent soil from the wash re-depositing back on to the clothes), there is achieved an anti-greying effect which can be measured using, in the case of the present specification, a Y value (see below). The DSPB when liberated from the sheet is transferred to the clothes in the wash and provides an optical whitening effect to the clothes which can be measured using, in the case of the present specification, a W value (calculated according to the Ganz formula) (see below).

It is also important that the sheet which includes the DSPB is packaged in such a way as to prevent unnecessary exposure to UV radiation as this will have a deleterious effect on the effectiveness of the sheet when subsequently used. Methods for packaging to prevent unnecessary UV exposure are well known and need not be taught here.

In order to determine the effectiveness of the sheet, the following protocol was followed where, in all cases, a sheet according to the invention (hereinafter referred to as a test sheet) was used in each wash. The test sheet was in a dry condition prior to use and it comprised the following composition viz: substrate (in the form of a polypropylene spunbond hydrophilic substrate) 82.83%; PVP 9.54%; DSPB 7.34% and pigment 0.29%; the liquid composition comprising water 88.3%; PVP 6.5%; DSPB 5.00% and pigment 0.20%. The detergent used is sold under the brand name Bonux® liquid which is manufactured by Procter and Gamble of Cincinnati, OH 45202, USA. It was selected because it contains a relatively low level of optical brightening agent and, in the market place, is relatively cheaper than other well known brands. All of the test pieces were white and the spectrophotometer used was Spectrophotometer CM-3610d manufactured by Konica Minolta of Osaka, Japan. The calibration reference material or swatch was a Hohenstein "White Scale" (Calibration Standard) Type 2 available from the Hohenstein Institute of Schloss Hohenstein, 74357 Boennigheim, Germany.

The protocol followed is the CTTN-IREN Anti-greying Protection procedure from the Research Institute for Textile Cleaning (Institut de recherche sur I'entretien et le nettoyage) of Avenue Guy de Collongue, BP. 41 , 69131 Ecully Cedex, France.

It will be appreciated that prior to use, the test sheets are in a dry condition meaning that the moisture content was zero. Similarly, after use and prior to being tested in the Spectrophotometer, the test sheets are dried to ensure the moisture content was zero.

One new Greying swatch is used per wash according to the CTTN protocol. Three 10cm x 10cm pieces of fabric viz: cotton (Krefeld 10A according to DIN 53919), polycotton (Krefeld 20A), polyester (Krefeld 30A), and polyamide (Krefeld 40A) where pinned on three different cotton cloths. The Krefeld 10A, Krefeld 20A, Krefeld 30A & Krefeld 40A fabrics are available from WFK Testgewebe GmbH of Christenfeld 10, 41379 Bruggen, Germany under references 1000, 2000, 3000 & 4000, respectively. The same Krefeld pieces are used for 10 cumulative washes. Abcotton ballast was used in each test. Ballast refers to clean white clothes which are used to simulate average domestic washing conditions and to bring the total dry weight of the wash to 3kg. The detergent was added according to the manufacturer's recommendations for a medium soiled wash and medium water hardness, which corresponds, in the case of Bonux® liquid, to 73ml or 75g. Two measurements were taken per piece of fabric before and after each wash using the Spectrophotometer and the results averaged for each type of fabric. Two measurement were taken per piece as the

Spectrophotometer only samples a relatively small area of the sheet and thus, two measurements from different locations were taken.

The clothes washing machined used was a Miele® Novotronic® W 526 available from Miele of Gutersloh, Germany. The wash temperature in each case was at 40°C. The water hardness was 25 +/- 2 French degrees.

Thus, as noted with respect to the test results labelled Krefeld 10A, the W (Ganz) and Y are presented. However, in the case of the test results labelled Krefeld 20A, Krefeld 30A, and Krefeld 40A, only the W (Ganz) value is presented. In each case, W (Ganz) and Y values were calculated before and after wash for each test piece. Ten washes were performed in the absence of a test sheet and ten in the presence of a test sheet. The following results were obtained. TABLES 1 and la

WITHOUT TEST SHEET - COTTON

TABLES 2 and 2a

WITHOUT TEST SHEET - POLYCOTTON

WITH TEST SHEET - POLYCOTTON

TABLES 3 and 3a

WITHOUT TEST SHEET - POLYESTER

TABLES 4 and 4a

WITHOUT TEST SHEET - POLYAMIDE

WITH TEST SHEET - POLYAMIDE

TABLES 5 and 5a

WITHOUT TEST SHEET - COTTON

In Table 1 , there is provided the results of the Whiteness W(Ganz) value for each of three cotton (Krefeld 10A test pieces (1 , 2 and 3) in the absence of a test sheet. The first column is the W(Ganz) value before any washes are performed on the test piece with the columns 1 - 10 giving the results for each of 10 washes per test piece. In Table 1a, there is provided the results of the W (Ganz) value for each of three cotton (Krefeld 10A test pieces (1 , 2 and 3) in the presence of a test sheet. The first column is the W(Ganz) value before any washes are performed on the test piece with the columns 1 - 10 giving the results for each of 10 washes per test piece. Similarly, Tables 2, 2a are results where the test pieces are polycotton (Krefeld 20A) without and with a test sheet respectively.

Similarly, Tables 3, 3a are results where the test pieces are polyester (Krefeld 30A) without and with a test sheet respectively.

Similarly, Tables 4, 4a are results where the test pieces are polyamide (Krefeld 40A) without and with a test sheet respectively.

Tables 5, 5a are results where the test pieces are cotton (Krefeld 10A) without and with a test sheet respectively but in respect of the luminosity value Y (opposite to greyness).

Figure 1 (Graph A) is a plot of the average results taken from Tables 1 and 1a. Thus, the W (Ganz) value (y-axis) is plotted against wash numbers (x axis) and it will be observed that, even after the first wash, the difference in W (Ganz) value is 80. A difference of 10 or greater can be visibly perceived as being whiter.

Figure 2 (Graph B) is a plot of the average results taken from Tables 2 and 2a. Figure 3 (Graph C) is a plot of the average results taken from Tables 3 and 3a. Figure 4 (Graph D) is a plot of the average results taken from Tables 4 and 4a. Figure 5 (Graph E) is a plot of the average results taken from Tables 5 and 5a.

It will be observed that whereas a significant whiteness (optical brightness) is achieved with respect to polycotton and polyamide, the effect is not as significant in relation to polyester. However, after 10 washes, the polyester sample achieved a W (Ganz) difference of 20. Figure 5 (Graph E) provides a plot of the Y value (y axis) (Y represents luminosity (opposite to greyness)) against wash numbers (x-axis) derived from the average figures from Tables 5, 5a. It will be observed from Figure 5 (Graph E) that the difference between the Y value in the absence of a test sheet and the Y value in the presence of a test sheet is significant. When the test material is washed a greater number of times, its Y value is significantly higher in the presence of the test sheet than that the Y value in the absence of a test sheet.

From the Figures, it will be observed that in each of the graphs A - D, the W (Ganz) value (optical brightness) is plotted versus the number of washes in respect of each of the 3 test pieces over a 10 wash cycle with and without the presence of the test sheet. It has been noted that where there is a difference of a W (Ganz) value of greater than 10 units, the whiteness (on the cloth) can be perceived by a consumer. Thus, it will be observed from Figure 1 (Graph A) that after just one wash, the difference in W (Ganz) value between the article washed in the absence of a test piece and the use of a test sheet is approximately 80 which is a considerable effect from a whiteness perspective. In the same graph after the 10th wash, the difference is 70. The reason why the W (Ganz) value increases in the absence of a test sheet is because the detergent used has a relatively low amount of an optical brightener which has a cumulative effect on the test piece. Figures 2 - 4 (Graphs B-D) may be interpreted in a similar manner. In Figure 3 (Graph C), where the test piece used is a polyester, it will be appreciated that the effect is not as significant as it is for cotton, polycotton or polyamide. Nevertheless, over 10 washes, there is at least a W (Ganz) value difference of 10 units as between the use of a test sheet and the absence of a test sheet according to the invention.

Figure 6 represents a view of the components used to manufacture a sheet according to the invention.

With reference to Figure 6, a roll of substrate in the form of a polypropylene spunbond hydrophilic substrate 1 having a weight of approximately 50g.m² (gsm) and a width of approximately 1.6m feeds a web 2 of the substrate 1 into a reservoir 3 using suitable rollers 4a, 4b, 4c and 4d to guide the web 2. In the reservoir 3 is an aqueous mixture of the actives used in the production of a sheet material in accordance with the invention. When the web 2 having the actives thereon emerges from the reservoir 3, it passes between two rollers 5 and 6 which exert a pressure of 1.39MPa to release excess liquid from the web 2 back into the reservoir 3 via the liquid guide element 7. The web 2 then passes under a first tension roller 8 before passing over four sets of three rollers each and is subsequently wound as a roll 10 of sheet material which is subsequently cut into the desired sized sheets in a well known fashion. The manner of production of the sheet material is well within the skill of a person skilled in the art and can be varied as desired. The velocity of the web 2 as it passes through the reservoir 3 is approximately 60m per minute. The temperature of the aqueous mixture in the reservoir 3 is maintained in a conventional manner at between 15°C and 25°C, preferably 20°C. However, given the nature of the substrate, it is important that the step of drying the web 2 is performed with care. Thus, the first set of rollers 15 comprises rollers 21 , 22 and 23 which are heated in a conventional manner to a temperature in the range of from 30°C and 50°C, preferably 40 C. The second set of rollers 16 comprises rollers 31 , 32 and 33 having a temperature in the range of from 50°C and 70°C, preferably 60°C. The third set of rollers 17 comprises rollers 41 , 42 and 43 having a temperature in the range of from 70°C and 90°C, preferably 80°C. The fourth set of rollers 18 comprises rollers 51 , 52 and 53 having a temperature in the range of from 100°C and 125°C, preferably 120°C. The rollers can be heated in a conventional manner known to those skilled in the art. The dwell time of the web per roller should preferably be approximately 2-3 seconds.

In an embodiment, in order to provide a sheet having the desired characteristics:

the substrate is in the form of a polypropylene spunbond hydrophilic substrate and comprises about 82.83%;

the optical brightener is in the form of Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and comprises about 7.34%;

the anti-soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP) and comprises about

9.54%;

the pigment is in the form of a copper phthalocyanine and comprises about 0.29%;

the percentages being % by weight of the sheet, the liquid composition present in the reservoir 3 has the following characteristics: the water is present in an amount of about 88.3%;

the PVP is present in an amount of about 6.5%;

the DSPB is present in an amount of about 5.0%; and

the pigment is present in an amount of 0.20%, the percentages being % by weight of the liquid composition.

The invention is not limited by or to the specific embodiments described which can undergo considerable variation without departing from the scope of the invention.

Claims

Claims:

A laundry sheet comprising a non-woven substrate impregnated with an optical brightener and/or a first anti-soil re-deposition agent.

A laundry sheet as claimed in claim 1 , wherein the non-woven substrate is selected from wet-laid, spun lace, spun bond, needle punch and air laid materials.

A laundry sheet as claimed in claim 2, wherein the wet laid non-woven substrate is formed from viscose fibres and/or pulp fibres; the spun lace non-woven substrate is formed from cellulosic fibres and/or hydrophilic synthetic fibres; the spun bond non- woven substrate is formed from polypropylene spun bond hydrophilic fibres and/or polyester fibres; the needle punch non-woven substrate is formed from cellulosic fibres and/or hydrophilic synthetic fibres; the air laid non-woven substrate is formed from viscose fibres and/or pulp fibres.

A laundry sheet as claimed in any of claims 1-3 wherein the substrate is a polypropylene spunbond hydrophilic substrate.

A laundry sheet as claimed in any of claims 1-4 in which the substrate is further impregnated with a second anti-soil re-deposition agent.

A laundry sheet as claimed in any of claims 1-5 wherein the optical brightener is Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP); the first anti-soil re-deposition agent is polyvinylpyrrolidone (PVP); and the second anti-soil re-deposition agent is a modified polyester co-polymer.

A laundry sheet as claimed in any of claims 1-6 which further comprises a pigment such as copper phthalocyanine.

A laundry sheet as claimed in claim 1 in which the substrate is a polypropylene spunbond hydrophilic substrate and is present in an amount of from about 69.1 % to about 90.85%; the optical brightener is Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and is present in an amount of from about 4.5% to about 17.4%; the first anti-soil re-deposition agent is

polyvinylpyrrolidone (PVP) and is present in an amount of from about 4.5% to about

17.4%; and further comprises a pigment wherein the pigment is copper phthalocyanine and is present in an amount of from about 0.15% to about 1.45%, the percentages being % by weight of the sheet.

A laundry sheet as claimed in claim 8 wherein the substrate comprises about 82.83%; the optical brightener comprises about 7.34%; the first anti-soil re- deposition agent comprises about 9.54%; and the pigment comprises about 0.29%, the percentages being % by weight of the sheet.

A laundry sheet as claimed in claim 1 in which the substrate is a polypropylene spunbond hydrophilic substrate and is present in an amount from about 67.9% to about 89.3%; the optical brightener is in the form of Disodium 2,2'-([1 , 1 '-biphenyl]- 4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and is present in an amount from about 3.6% to about 1 1.2%; the first anti-soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP) and is present in an amount from about 4.7% to about 14.6%; and further comprises a pigment and a second anti-soil re-deposition agent; wherein the pigment is copper phthalocyanine and is present in an amount from about 0.01 % to about 1.4% and the second anti-soil re-deposition agent is in the form of a modified polyester co-polymer and is present in an amount from about 2.0% to about 6.1 %, the percentages being % by weight of the sheet.

A laundry sheet as claimed in claim 10 wherein the substrate is a polypropylene spunbond hydrophilic substrate and comprises about 79.86% by weight; the optical brightener comprises about 7.08%; the first anti-soil re-deposition agent comprises about 9.20%; the pigment comprises about 0.04%; and the second anti-soil re- deposition agent comprises about 3.82%, the percentages being % by weight of the sheet.

A laundry sheet as claimed in claim 1 wherein the substrate is a polypropylene spunbond hydrophilic substrate and is present in an amount of from about 91.9% to about 98.1 %; the optical brightener is Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and is present in an amount of from about 1.7% to about 6.6%; and further comprises a pigment wherein the pigment is copper phthalocyanine and is present in an amount of from about 0.17% to about 1.71 %, the percentages being % by weight of the sheet.

A laundry sheet as claimed in claim 12, wherein the substrate comprises about 95.43%; the optical brightener comprises about 4.23%; and the pigment comprises about 0.34%, the percentages being % by weight of the sheet. A laundry sheet as claimed in claim 1 wherein the substrate is a polypropylene spunbond hydrophilic and is present in an amount of from about 79.0% to about 98.3%; the first anti-soil re-deposition agent is polyvinylpyrrolidone (PVP) and is present in an amount of from about 1.7% to about 21.0%, the percentages being % by weight of the sheet.

A laundry sheet as claimed in claim 14 wherein the substrate is a polypropylene spunbond hydrophilic and comprises about 89.67%; the first anti-soil re-deposition agent is in the form of polyvinylpyrrolidone (PVP) and comprises about 10.33%, the percentages being % by weight of the sheet.

A laundry sheet as claimed in claim 1 wherein the substrate is a polypropylene spunbond hydrophilic and is present in an amount of from about 93.3% to about 98.3%; the optical brightener is Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and is present in an amount of from about 1.7% to about 6.7%, the percentages being % by weight of the sheet.

A laundry sheet as claimed in claim 16 wherein the substrate is a polypropylene spunbond hydrophilic and comprises about 95.76%; the optical brightener is in the form of Disodium 2,2'-([1 , 1 '-biphenyl]-4,4'- diyldivinylene)bis(benzenesulphonate) (DSBP) and comprises about 4.24%, the percentages being % by weight of the sheet.