Flushable wipes

Abstract

A wipe comprises fibres selected from at least one of cellulosic material, polyvinyl acetate (PVA) or a combination thereof; together with a binder which is soluble in water at standard ambient temperature and pressure (SATP). The wipe can be flushed away and is suitable for carrying a solution. The wipe is especially suitable for carrying a solution for medical purposes.

Claims

1. A wipe which comprises fibres of (a) polylactic acid (PLA), modified PLA, or cellulosic material and (b) polyvinyl acetate (PVA); together with a binder which is soluble in water at standard ambient temperature and pressure (SATP), wherein the binder is carboxymethylcellulose (CMC); and wherein the wipe comprises about 5% PVA fibres by weight and about 4% CMC by weight, and is water soluble at standard ambient temperature, or passes drainline and sewer disintegration tests as defined in the UKWIR flushability protocol, wherein said protocol comprises a dispersibility shake flask test having a rinse time of about 1 minute and a sieve size of about 5.6 mm, and wherein the PVA fibres comprise a mixture of about 4% PVA fibres which are insoluble in liquid water at 20 C. and 101,325 kPA and about 1% PVA fibres which are soluble in liquid water at 20 C. and 101,325 kPA.

2. A wipe according to claim 1, wherein the cellulosic material is selected from at least one of cellulose, rayon, regenerated cellulose, or a combination of at least two or more thereof.

3. A wipe according to claim 1, wherein the fibres are formed into fibres and the fibres are assembled into a tissue which is bound by the binder.

4. A wipe according to claim 1, which comprises no other materials.

5. A wipe according to claim 1, wherein the wipe is impregnated with one or more non-aqueous solvents.

6. A wipe according to claim 5, wherein the non-aqueous solvents are selected from one or more of liquid barrier film (LBF) fluid, oily silicone based solutions, polydimethyl siloxanes, or one or more surfactants.

7. A wipe according to claim 5, which carries a non-aqueous solvent, selected from a LBF or silicone fluid, a citrus oil optionally selected from orange oil, an oil-based make-up remover for cosmetic purposes, or a cleaning composition comprising a surfactant, or an anti-bacterial agent.

8. A sachet inside which is sealed a wipe according to claim 1.

9. A sachet according to claim 8, wherein the sachet further contains about 1 ml to about 2 ml of non-aqueous solvent.

10. A wipe according to claim 7, wherein the surfactant is a non-ionic surfactant.

11. A wipe according to claim 10, wherein the non-ionic surfactant is an amine oxide based non-ionic surfactant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described by way of example with reference to the accompanying drawings, in which:

(2) FIG. 1 shows the results of a drain line disintegration test on a first wipe according to the invention;

(3) FIG. 2 shows the results of a drain line disintegration test on a first wipe according to the invention impregnated with LBF fluid;

(4) FIG. 3 shows the results of a drain line disintegration test on a second wipe according to the invention;

(5) FIG. 4 shows the results of a drain line disintegration test on a second wipe according to the invention impregnated with a silicone based solvent;

(6) FIG. 5 shows the results of a sewer disintegration test on a first wipe according to the invention;

(7) FIG. 6 shows the results of a sewer disintegration test on a first wipe according to the invention impregnated with LBF fluid;

(8) FIG. 7 shows the results of a sewer disintegration test on a second wipe according to the invention; and

(9) FIG. 8 shows the results of a sewer disintegration test on a second wipe according to the invention impregnated with a silicone based solvent.

DETAILED DESCRIPTION OF THE INVENTION

(10) Within the context of this specification the word comprises is taken to mean includes, among other things. It is not intended to be construed as consists of only.

(11) The word about is taken to mean optionally plus or minus 20%, more preferably optionally plus or minus 10%, even more preferably optionally plus or minus 5%, even more preferably optionally plus or minus 2.5%, most preferably optionally plus or minus 1%.

(12) Within the context of this specification, standard ambient temperature and pressure (SATP) is defined as a temperature of 298.15 K (25 C., 77 F.) and an absolute pressure of 100 kPa (14.504 psi, 0.987 atm).

(13) Within the context of this specification, soluble PVA is taken to mean that the PVA dissolves in liquid water at room temperature (about 20 C.) and room pressure (about 101.325 kPa).

(14) Within the context of this specification, the term non-aqueous solvent is intended to mean a predominantly hydrophobic solvent. This means that water can be present within the solvent as long as the water molecules are trapped in the solvent and are not free to break down the wipe of the invention. For example, a water in oil emulsion, silicone based solution, or a composition comprising water and alcohol wherein the composition does not comprise predominantly water are non-aqueous solvents within the context of the invention. In one example, non-aqueous solvent comprises liquid barrier film (LBF) or silicone fluid. For example, the silicone fluid is a silloxane compound or combination of silloxane compounds. For example, the silicone fluid is selected from one or more of hexamethyl disiloxane, octamethyl trisiloxane, decamethyl tetrasiloxane, decamethyl cyclo pentasiloxane or a combination of at least two or more thereof.

(15) For the purposes of clarity and a concise description, features are described herein as part of the same or separate embodiments; however it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.

(16) A wipe constructed in accordance with the present invention is approximately about 100 mm by about 150 mm, with a thickness of about 0.5 to about 2 mm. The wipe comprises cellulosic fibres, such as cellulose and/or rayon, which are cross-linked with polyvinylalcohol (PVA) fibres. The PVA material is inert and bio-degradable and acts to bind the cellulosic fibres together, acting almost as a staple to maintain the stability and strength of the wipe. The PVA preferably comprises water-soluble PVA and dissolves in contact with water causing the wipe to disintegrate.

(17) The process of manufacture of a wipe according to the invention comprises a producing a slurry of cellulosic material and PVA. The slurry comprises disbursed cellulosic material and PVA fibres. The fibres are deposited onto a screen which comprises a belt. The fibres are drawn by the belt through a drying oven and CMC is sprayed onto the drying fibres. The CMC acts as a binder to bind the fibres together. Dried tissue is extracted from the drying oven and cut into wipes. Preferably, the wipes are impregnated with one or more non-aqueous solvents and each wipe is sealed inside a sachet.

(18) In an alternative embodiment, the process includes spunlace bonding, also known as spunlaced bonding or hydroentangling. In this method, a web of fibres is bonded by interlocking and entangling the fibers about each other with high velocity streams, jets or curtains of water. The web or fabric may have other bonding methods in addition to spunlacing. This method is used in the production of paper by using non-woven manufacturing technology.

(19) The wipe optionally carries a non-aqueous solvent, depending on the wipe's intended use. For example, if the wipe is to be used to apply skin protection, the wipe carries a LBF or silicone fluid, for example a solvent comprising poly dimethyl siloxanes. If a user wishes to apply a silicone coating to their skin, the wipe is passed over the skin and silicone is transferred to act as a skin barrier. If the wipe is to be used to dissolve adhesive material on the skin surface, the wipe preferably carries a citrus oil, such as orange oil. If a user wishes to remove adhesive from the skin's surface, the wipe is passed over the skin and the citrus oil is transferred to remove the adhesive. It is also envisaged that in further embodiments of the invention, the wipe carries an oil-based make-up remover for cosmetic purposes, or a cleaning composition, or an anti-bacterial agent for domestic cleaning purposes or for skin disinfection or cleansing.

(20) In use, the wipe is folded and stored in a sachet. It remains stable in the packaging, which can easily be torn open to remove the wipe for use. In the envisaged medical application of the wipe, it is passed over the skin to apply the non-aqueous fluid contained thereon. After use of the wipe, the wipe is disposed of by placing in a toilet bowl and flushing away to a sewer. The PVA and CMC in the wipe rapidly dissolves with the result that the cross-links between adjacent cellulose fibres are destroyed and the wipe disintegrates before being flushed away. The wipe is fully biodegradable and will not clog up a plumbing system, drain or sewer.

EXAMPLES

(21) Testing was conducted to establish the preferred composition of the flushable wipe and the method and results are set out below:

(22) Six dry samples of a small medical wipe having a composition A (Fabric A) and four dry samples of a small medical wipe having a composition B (Fabric B) were supplied for testing. (Composition A comprises a wipe according to the invention comprising rayon, 4% insoluble PVA by weight, 1% soluble PVA by weight, and 4% carboxymethyl cellulose binder by weight. Composition B comprises a wipe according to the invention comprising rayon, 5% insoluble PVA by weight and 4% carboxymethyl cellulose binder by weight). Three of the samples having composition A were impregnated with LBF fluid and two of the samples having composition B were impregnated with a silicone based liquid barrier film and they were also submitted for testing. The reason for testing dry and impregnated samples was to separately investigate the properties of the wipe (by testing the dry samples) and any effect the LBF or silicone based liquid barrier film had on the disintegration properties (by testing the impregnated samples).

(23) The UKWIR Flushability Protocol has been developed to assess the suitability for disposal to sewer of potentially flushable products. It comprises of ten stages, at each stage a test(s) is (are) undertaken to assess a particular aspect of the product.

(24) A full product approval requires all stages to be assessed. However, an indication of a products flushability can be gained by undertaking established drainline and sewer disintegration tests. These tests are designed to assess a products ability to break down in the drainage system after being flushed. Experience has shown that it is these disintegration tests, which are undertaken by agitating the product in a shake flask for 3 hours and 6 hours duration respectively, that are likely to be most difficult tests to pass. Hence it will be these tests that mostly define if a product is flushable or not.

(25) With the above in mind, a series of drainline and sewer disintegration tests have been undertaken for each of the fabrics, both in the dry and solvent impregnated states.

(26) Drainline Disintegration Test

(27) The drainline disintegration test consists of a shake flask disintegration test.

(28) A sample (consisting of one medical wipe) was added to one litre of water in a flask, which was agitated for 3 hours at 100 rpm. The extent of product separation after rinsing was measured at the end of the test.

(29) For the product to pass this test at least 50% of the product mass must pass through a 12.5 mm perforated plate sieve and the largest sample of the remaining product must measure no more than 25 mm in its largest dimension.

(30) Six tests were undertaken with Fabric A (three dry and three treated with solvent) and four tests were carried out with Fabric B (two dry and two treated with solvent).

(31) Test ResultsFabric A

(32) The results of the six tests are given in Table 1. This shows the initial mass of the product before testing, the mass retained on the sieve after testing and hence the proportions held on/passing through the sieve.

(33) TABLE-US-00001 TABLE 1 Drainline disintegration test results - Fabric A A + A + A + DRY A DRY A DRY A 2 ml 2 ml 2 ml Sample ID 3 hr - A 3 hr - B 3 hr - C 3 hr - D 3 hr - E 3 hr - F Initial dry 0.36 0.48 mass* (g) (Estimated as average of 3 samples.) Dry mass 0.29 0.30 0.28 0.27 0.30 0.28 retained on the 12.5 mm sieve after 3 hours agitation at 100 rpm (g) Percentage 19% 16% 22% 44% 37% 42% passing through the 12.5 mm perforated plate sieve Observations See FIG. 1. See FIG. 2. Pass/fail results FAIL FAIL FAIL FAIL FAIL FAIL

(34) FIGS. 1 and 2 show photographs of the dry and treated samples respectively, at the following stages during the testing process: The sample still in the flask after completing the 3 hours of agitation. The sample on the 12.5 mm perforated plate sieve before rinsing. The perforated plate sieve after sample rinsing.

(35) The results show that signs of disintegration can be observed at the end of the agitation but the product is still identifiable as a wipe and still mostly in one piece when placed on the sieve. The rinsing of the samples achieves some disintegration of the product.

(36) Test ResultsFabric B

(37) The results of the four tests are given in Table 2. This shows the initial mass of the product before testing, the mass retained on the sieve after testing and hence the proportions held on/passing through the sieve.

(38) TABLE-US-00002 TABLE 2 Drainline disintegration test results - Fabric B Sample ID DRY B DRY B B + 2 ml B + 2 ml 3 hr - G 3 hr - H 3 hr - I 3 hr - J Initial dry mass* 0.39 0.50 (g) (Estimated as average of 2 samples.) Dry mass 0 0 0 0 retained on the 12.5 mm sieve after 3 hours agitation at 100 rpm (g) Percentage 100 100 100 100 passing through the 12.5 mm perforated plate sieve Observations See FIG. 3. See FIG. 4. Pass/fail results PASS PASS PASS PASS

(39) FIGS. 3 and 4 show photographs of the dry and treated samples respectively, at the following stages during the testing process: The sample still in the flask after completing the 3 hours of agitation. The sample on the 12.5 mm perforated plate sieve before rinsing. The perforated plate sieve after sample rinsing.

(40) The results show a high degree of disintegration of the samples in the flasks, to a degree where single fibres can be identified. Where lumps of fibres were observed in the flasks at the end of the agitation, the gentle rinsing process was sufficient to wash out the fibres so that none were retained on the sieve.

(41) Sewer Disintegration Test

(42) The sewer disintegration test forms part of the UKWIR Flushability Protocol and consists of a shake flask disintegration test. The sample (consisting of one medical wipe) is added to one litre of water in a flask, which is agitated for 6 hours at 150 rpm. The extent of product separation after rinsing is measured at the end of the test.

(43) For the product to pass this test at least 80% of the product mass must pass through a 5.6 mm perforated plate sieve.

(44) Six tests were undertaken with Fabric A (three dry and three treated with LBF fluid) and four tests were carried out with Fabric B (two dry and two treated with silicone based solvent).

(45) Test ResultsFabric A

(46) The results of the six tests are given in Table 3. This shows the initial mass of the product before testing, the mass retained on the sieve after testing and hence the proportions held on/passing through the sieve.

(47) The test requires assessing the disintegration using a perforated plate sieve of 5.6 mm.

(48) Additional analysis of the sample was carried out using a 3.15 mm sieve to demonstrate whether further disintegration of the fabric is observed. Those results are presented here for information.

(49) FIGS. 5 and 6 show photographs of the dry and treated samples respectively, at the following stages during the testing process: The sample still in the flask after completing the 6 hours of agitation. The sample on the 5.6 mm perforated plate sieve before rinsing. The perforated plate sieve after sample rinsing.

(50) The results show a high degree of disintegration of the samples in the flasks: lumps of fibres that make the fabric can be observed in the flasks; these lumps are washed during rinsing and demonstrate that little pressure is required to break-up the product further.

(51) However, a residue was observed on the flasks at the end of the test of the sample with the LBF fluid.

(52) TABLE-US-00003 TABLE 3 Sewer disintegration test results - Fabric A DRY DRY A DRY A A + 2 ml A + 2 ml A + 2 ml A 6 hr - 6 hr - 6 hr - 6 hr - 6 hr - 6 hr - Sample ID A2 B2 C2 D2 E2 F2 Initial dry mass* (g) 0.36 0.48 (Estimated as average of 3 samples) Dry mass retained on 0 <0.05 0 0 0 <0.05 the 5.6 mm sieve after 6 hours agitation at 150 rpm (g) Percentage passing 100% 94% 100% 100% 100% 97% through the 5.6 mm perforated plate sieve Pass/fail results PASS PASS PASS PASS PASS PASS Dry mass retained on <0.05 g <0.05 g 0 <0.05 g <0.05 g <0.05 g the 3.15 mm sieve after 6 hours agitation at 150 rpm (g) Percentage passing 98% 90% 100% 99% 99% 89% through the 3.15 mm perforated plate sieve Observations at 30 min Still mostly together as Still mostly together as one whole wipe, break up one whole wipe, break up has started. has started. At 90 min Much more broken up but Much more broken up but still some clumps. still some clumps. Water cloudy At 3 hours Mostly broken up, some Mostly broken up, some fibres still together. fibres still together. Water cloudy. At 6 hours Mostly disintegrated, Mostly disintegrated, some some fibres still together. fibres still together. See FIG. 5. Water cloudy and residue evident around the waterline. See FIG. 6.

(53) Test ResultsFabric B

(54) The results of the four tests are given in Table 4. This shows the initial mass of the product before testing, the mass retained on the sieve after testing and hence the proportions held on/passing through the sieve.

(55) The test requires assessing the disintegration using a perforated plate sieve of 5.6 mm.

(56) Additional analysis of the sample was carried out using a 3.15 mm sieve to demonstrate whether further disintegration of the fabric is observed. Those results are presented here for information.

(57) FIGS. 7 and 8 show photographs of the dry and treated samples respectively, at the following stages during the testing process: The sample still in the flask after completing the 6 hours of agitation. The sample on the 5.6 mm perforated plate sieve before rinsing. The perforated plate sieve after sample rinsing.

(58) The results show a high degree of disintegration for both the dry and samples treated with silicone based solvent after the 6 hour test. Even prior to rinsing, very little proportion of the fibres is retained on the sieves.

(59) However, a residue was observed on the flasks at the end of the test of the sample with the silicone fluid.

(60) TABLE-US-00004 TABLE 4 Sewer disintegration test results - Fabric B Sample ID DRY B DRY B B + 2 ml B + 2 ml 6 hr - G2 6 hr - H2 6 hr - I2 6 hr - J2 Initial dry mass* 0.39 0.50 (g) (Estimated as average of 2 samples.) Dry mass retained 0 0 0 0 on the 5.6 mm sieve after 6 hours agitation at 150 rpm (g) Percentage passing 100% 100% 100% 100% through the 5.6 mm perforated plate sieve Pass/fail results PASS PASS PASS PASS Dry mass retained 0 0 0 0 on the 3.15 mm sieve after 6 hours agitation at 150 rpm (g) Percentage passing 100% 100% 100% 100% through the 3.15 mm perforated plate sieve Observations After 30 min: already After 30 min: already disintegrated, water disintegrated, water cloudy. cloudy. After 90 min/3 hour/ 90 min/3 hour: as 30 min. 6 hour: as 30 min. 6 hour: as 30 min & See FIG. 7. residue evident around the waterline. See FIG. 8.

(61) Summary of Results

(62) In the drainline disintegration test, when less and shorter agitation is applied, Fabric A performs less well than Fabric B. Nevertheless, the level of disintegration observed for fabric A treated with LBF fluid is very promising and disintegration level is close to the pass criteria. Fabric B performs well in the drainline disintegration test.

(63) Both A and B types of fabric show very good performance when assessed against the sewer disintegration test, with most or all of the products disintegrating into small fibres.

(64) The results are summarised in Table 5 below:

(65) TABLE-US-00005 TABLE 5 Summary of results Sample ID DRY A + DRY B + A 2 ml B 2 ml Drain- Pass criteria At least 50% of the product mass line shall pass through a 12.5 mm disinte- perforated plate sieve and the gration largest sample of the remaining product shall measure no more than 25 mm in their larger dimension. Percentage passing 16 to 37% to 100% 100% through the 12.5 mm 22% 44% (n/a) (n/a) sieve after 3 hours (pieces (pieces agitation at 100 rpm above above (+observation on 25 mm 25 mm remaining on sieve) on sieve) material on sieve) Conclusion FAIL FAIL PASS PASS Sewer Pass criteria At least 80% of the product mass disinte- shall pass through a 5.6 mm gration perforated plate sieve. test Percentage passing 94% to 97% to 100% 100% through the 5.6 mm 100% 100% sieve after 6 hours agitation at 150 rpm Conclusion PASS PASS PASS PASS

(66) The above described embodiments have been given by way of example only, and the skilled reader will naturally appreciate that many variations could be made thereto without departing from the scope of the claims.