WO1995028140A1

WO1995028140A1 - An absorbent assembly

Info

Publication number: WO1995028140A1
Application number: PCT/AU1995/000215
Authority: WO
Inventors: Maxine Driesen; Rohan Jenger
Original assignee: Buddies Australia Pty. Ltd.
Priority date: 1994-04-13
Filing date: 1995-04-13
Publication date: 1995-10-26
Also published as: AUPM503094A0; NZ283704A

Abstract

An absorbent assembly (10) for a bed sheet, bed pad, pillow, nappy or underpants or the like. The absorbent assembly (10) comprises a first layer (12) made from a non-absorbent fluid permeable material and a second layer (14) below said first layer (12). The second layer (14) is made from a substantially non-absorbent material. A third layer (16) is positioned below said second layer (14). The third layer (16) comprises fibres of hydrophilic and hydrophobic materials needled together so as to form a felt.

Description

AN ABSORBENT ASSEMBLY

The present invention relates to an absorbent assembly and more particularly to an absorbent assembly used in the care of incontinent patients.

There are many ways of treating incontinent adult patients. Some patients are managed by means of an in-dwelling catheter. However, the use of such a catheter is not always recommended and may not be suitable for some patients. A variety of occlusive appliances are available to treat some patients but these are often not accepted by elderly or confused patients. Accordingly, there are a large number of incontinent patients that are nursed in bed and who require frequent changes of bed linen to maintain hygiene levels, avoid embarrassment and discomfort. The level of care required to be provided by nursing staff to patients with incontinence is accordingly very high. This high level of care imposes a large burden on the nursing staff and laundering facilities.

In order to reduce discomfort to the patient as a result of incontinence and to help nursing staff, disposable and non-disposable products have been developed to absorb fluids such as urine. Through the years, it has been found that such disposable and non-disposable products suffer from many disadvantages. For example, disposable incontinence products tend to become quickly saturated with the surface of the product remaining wet even after passage of the fluid therethrough. Surface wetness of the product is a severe disadvantage and may result in pressure sores and other problems for the patient.

Other disposable products, which are typically made of paper, tend to disintegrate and stick to die patient's skin. Some such products have also been unable to contain the fluid properly and thus fluid passing through the incontinence product causes wetting of the bed linen and mattress.

Non-disposable incontinence products also have problems. For example, it has been found that they do not withstand frequent laundering. As such products are quite expensive it is essential that they can be laundered repeatedly, without damaging their effectiveness. It has been found that with prior art products some fibres of the felted absorbing material become loose and wash away. This reduces die overall strength of the product and its ability to absorb fluid. Another problem with such products is that as a result of laundering die felted absorbing material shrinks causing the top layer of the assembly to become corrugated. This makes the product quite uncomfortable to he upon and for some patients, especially die elderly, this may cause skin abrasion.

Another difficulty with conventional incontinence products is that they take a considerable time to dry. In order to decrease laundering costs it is desirable to minimise the time taken to dry incontinence products.

Australian patent no. 509028 describes improved assemblies for the management of incontinence. However, such assemblies have been found to exhibit unacceptable corrugation effects and unacceptable shrinkage. Such assemblies also suffer from rapid fibre loss when laundered and take too long to dry. Another problem with such assemblies is that they tend to buckle because of differential shrinkage between the synthetic scrim layer and the rayon material. This buckling causes discomfort to d e user.

The present invention seeks to provide an absorbent assembly or incontinence product which overcomes or at least alleviates some of the aforementioned problems.

According to a first aspect of the present invention there is provided an absorbent assembly comprising: a first layer made from a substantially non-absorbent fluid permeable material; a second layer below said first layer, said second layer comprising a substantially non-absorbent material; and a third layer below said second layer, said third layer comprising fibres of hydrophilic and hydrophobic materials needled together so as to form a felt. Preferably, the first, second and diird layers are quilted togedier, by for example stitching. The material of d e second layer serving to plump out the spaces formed between the first and diird layers as a consequence of the quilting.

Preferably, the first layer is formed from a brushed polyester material.

Preferably, die second layer is formed from a 100% polyester fibrofill or fibrous web material.

Preferably, die third layer comprises a mix of polyester and rayon fibres. The mix is preferably a 50/50% mix.

In one preferred embodiment of die invention, die polyester and rayon fibres forming the third layer are needled togedier and tiien subject to a diermal treatment so as to cause bonding between die polyester and rayon fibres. Typically, the thermal treatment comprises heating the needled third layer in a heat press.

The assembly may also comprise a fourth layer below die diird layer. The fourth layer is preferably made of a fluid impermeable material so as to prevent fluid leakage from the assembly. The fourth layer may be made from a nylon material with a polyurediane backing coat or a polyester material with a polyurethane backing coat.

The absorbent assembly may be incorporated an absorbent bed sheet, bed pad, pillow, underpants or any other appropriate construction.

An embodiment of die invention will now be described byway of example only, with reference to the accompanying drawings.

Figure 1 is a schematic cross-sectional view of an absorbent assembly according to a first embodiment of die invention; Figure 2 is a schematic assembly view of an absorbent assembly according to a second embodiment of the invention; and

The absorbent assembly 10 shown in Figure 1 comprises a first or top layer 12 made from a non-absorbent fluid permeable material, a second layer 14 comprising a non- absorbent material and a third layer 16 which comprises fibres of hydrophilic and hydrophobic materials which are needled togedier so as to form a felt.

In accordance with one embodiment of the invention, the top layer 12 is made from a material of 100% brushed polyester. The second layer 14 comprises a 100% polyester fibrofill or fibrous web of a density in the range 50 to 150 g/m². The fibres are preferably of a denier in the range 2 to 13, most preferably a mix of different deniers in diis range. Layer 14 may be made, e.g. by a spray-bonded process or by a needle pinch process.

The third layer 16 comprises a 50/50% rayon/polyester blend of fibres. The fibres of die third layer 16 are needled togedier so as to form a felted structure. As a consequence of needling die felted structure comprises a number of vertically extending fibres which are surrounded by horizontal fibres. The vertically extending fibres assist penetration and dispersion of fluid into die diird layer 16. Furthermore, die vertically extending fibres result in a "wicking" fluid action which assists passage of d e fluid into die diird layer 16. The needling of die fibres also results in pockets being formed in d e felted structure which pockets can hold fluid and dierefore increase die holding capacity of the diird layer 16.

To increase the tensile strength or breaking force of d e assembly 10 it is desirable to subject the needled diird layer 16 to a heat process which causes bonding or melding between die polyester and rayon fibres of the needled structure. By bonding d ese fibres together it has also been found diat die loss of fibres during laundering is significandy reduced. The heat process occurs generally at temperatures between 130 and 200°C. By providing die second layer 14 between die top layer 12 and diird layer 16 problems resulting as a consequence of shrinkage of die diird layer 16 are substantially reduced. As the diird layer 16 is made from a material having a felted structure it is inherent that tiiis layer will shrink to some extent as a consequence of laundering. With conventional products tiiis shrinkage has represented a significant problem as it causes ripples or corrugations to be formed in die felted layer which could be felt by die patient and were very uncomfortable to he upon. However, by providing die second layer 14 between the top layer 12 and die felted diird layer 16 die feel of any ripples or corrugations formed in die felted layer is niinimised to the patient. The second layer 14 of fibrofill material pads out die corrugations so tiiat die patient feels an essentially smooth or slightly rippled pad.

Figure 2 illustrates die construction of an absorbent blanket 50 having an absorbent assembly such as tiiat shown in Figure 1. The blanket 50 also includes cotton/polyester material side flaps 52 which bound die edge of die blanket 50. A water proof bottom layer 54 is provided to prevent fluid from seeping d rough the blanket 50 to die bed linen and mattress. The flaps 52 are preferably made of a 65/35% cotton/polyester mix material.

The advantageous nature of an embodiment of the invention will be readily apparent from the results of die following tests applied to absorbent bed sheets in accordance with an emrxκiiments of die present invention (Examples 1 and 2) and a comparative conventional product.

THE TEST METHODS:

Dimensional Stability to Washing - (AS 2001.5.4)

Type of Washing Machine: Front Loading Horizontal Rotating Drum Type Washing Procedure Code: 2A Drying Procedure: Tumble Dry-Hot No. of Washing Cycles: 5

No. of Drying Cycles: 1

Detergent Used: ECE Reference Detergent

Weight Loss after Dimensional Stability (AS 2001.5.4, See p.2) Weigh die Dimensional Stability sample before and after the test. Report weight loss as a percentage on original mass.

Speed of Absorption and Rate of Spread Sample Condition: 2 x cycles of AS 2001.5.4, Produce code 2A, and Hot Tumble

Dry, 70 ° C max.

Mark a 13 cm diameter circle (using a washable ink) on die polyester surface and position a 10 cm lengtii of styrene tubing, 2 cm in diameter, vertically in die centre of die circle and place a 100 gram annular weight on top of die tube. Pour 30 ml of 0.1% Sunset Yellow solution or equivalent at 37 °C into die tube and record d e time taken for d e tube to empty. Continue timing and record die time taken for die dye solution to reach the 13 cm diameter circle.

Limits: Speed of absorption : 20 seconds maximum

Rate of spread : 70 seconds maximum

Wick Back

Sample Condition: As above

This is a continuation of die above tests. Allow die sample to stand for 180 seconds after the circumference is reached. Place a weighed 15 cm No. 1 filter paper over die 13 cm diameter circle and place a 5.08 cm diameter steel cylinder weighing 2.14 kg (approximately 13.5 cm long) over the point of application of the dye solution. Allow to stand for 60 seconds and tiien re-weight the filter paper. Report increase in mass as a percentage on the initial mass. Tntal Fluid Absorption (Non-Routine) Sample Condition: As above

Cut a section of the quilted fabric 20 x 7.5 cm and weigh. Immerse in water at 37 °C for 60 seconds, remove and hang vertically for 30 seconds. Place the sample on 3 layers of Whatman 3 mm chromatography paper and traverse the 1 kg ASTM roller along the sample and back, taking about 5 seconds to complete die rolling. Re- weigh and calculate the total absorption as a percentage of the dry weight.

Limits: Not less dian 310%.

Mass Per Unit Area Measured as per AS2001.2.13

Breaking Force and Extension

Measured as per AS2001.2.3, metiiod C

Example 1

An absorbent bed sheet of a size of 100 x 100 cm having a top layer made from 100% brushed polyester, a second layer of 100% polyester fibrofill and a third needled layer of 50/50% rayon/polyester blend fibres. The diird layer was placed in a heat press at approximately 200 °C prior to insertion into the bed sheet assembly. The results of the tests on the absorbent bed sheet described in Example 1 are as follows:-

Mass per Unit Area: Mean Mass = 919.4 g/m^

Weight Loss after Dimensional Stability:

2.69 g = 1.2%

Breaking Force and Extension:

Original After Washing

Warp Breaking 1137 N 1132 N

Force (100.7 1916, 1242, 1188, 1110, 1110, 1239, 1106,

1332) 1094)

Elongation 65.8% 74.0% at Break (61.0, 55.1, 70.7, 68.6, 73.6) (73.4, 75.6, 76.7, 73.6, 70.8)

Weft Breaking 1095 N 812 N

Force 1088, 1212, 930, 1163, 1081 (720, 874, 839, 748, 877)

Elongation 78.2% 89.0%

Break (80.5, 79.9, 75.0, 79.9, 75.8) (81.4, 93.3, 90.7, 87.7, 91.9)

* After 5 X cycles of As 2001.5.4, Procedure Code 2A and Hot Tumble Dry (70 °C max) Mean Dimensional Change:

Warp: -3.5%

Weft: -2.5%

Speed of Absorption:

4.0 seconds

Rate of Spread:

19.7 seconds

Increase in Mass - Wick Back:

6.3%

Total Fluid Absorption: 430.3%

Example 2

An absorbent bed sheet of a size of 100 x 100 cm having a top layer made from 100% brushed polyester and a second needled layer of 50/50% rayon/polyester blend fibres. The second layer was placed in a heat press at approximately 200°C prior to insertion into the bed sheet assembly. The results of the tests on the absorbent bed sheet described in Example 2 are as

follows:-

Mass per Unit Area:

Mean Mass = 947.9 g/m²

Weight Loss after Dimensional Stability:

2.69 g = 1.5%

Breaking Force and Extension:

Warp: 1278 N (Original) Weft: 973 N (Original)

Speed of Absorption:

9.3 seconds

Rate of Spread:

25.2 seconds

Increase in Mass - Wick Back:

10.4% Total Fluid Absorption:

370%

COMPARATIVE EXAMPLE An absorbent bed sheet in accordance widi the teachings of Austrahan patent no. 509028. The bed sheet is of a size of 100 x 114 cm and comprises a top layer of 100% brushed polyester and a needled tiiree layer felted construction. The needled structures comprises a first layer of 100% rayon, a second layer of polypropylene scrim and a diird layer of 100% rayon.

The results of die tests on the absorbent bed sheet of die comparative example are as follows:-

Mass per Unit Area: Mean Mass = 929.8 g/m²

Weight Loss after Dimensional Stability:

5.23 g = 2.6%

Breaking Force and Extension:

*-*

Original After Washing

Warp Breaking 390 N 546 N Force (370, 383, 407, 418, 372) (499, 555, 567, 562)

Elongation at 13.3% 35.7%

Break (13.3, 13.3, 13.18, 13.6, (35.4, 35.4, 35.4., 36.6)

12.4)

Weft Breaking 164 N 403 N Force (179, 140, 149, 171, 181) (379, 389, 376, 432, 438)

Elongation at 9.3% 16.4% Break (10.1, 9.2, 8.6, 9.3, 9.2) (16.2, 16.0, 15.4, 17.3,

17.2)

* After 5 X cycles of As 2001. 5.4, Procedure Code 2A and Hot Tumble Dry (70 °C max)

Mean Dimensional Change: Warp: -6.0% Weft: -4.5%

Speed of Absorption: 10.3 seconds

Rate of Spread: 19.9 seconds

Increase in Mass - Wick Back:

18.6%

Total Fluid Absorption: 326.9%

Embodiments of the present invention are particularly advantageous for a number of reasons. For example, preferred embodiments have an increased capacity to hold fluids when compared to comparative prior art products and have an improved fluid absoφtion speed. This results in quicker conduction of fluid away from die skin and hence consequential user benefits in terms of skin integrity. Furthermore, the weight of products according to die present invention is reduced because the product does not include a scrim layer. The need for a scrim layer is eliminated because of the heat process applied to the third layer. The reduction in weight of die article facilitates movement of the product when fitting it on a bed, as well reducing the drying time of the product. This is particularly important when the product is laundered in a commercial laundry where drying time greatiy increases die cost of laundering the product.

It is also been fovmd that there is reduced shrinkage of the felted layer and the provision of a second layer serves to soften the effect of any rippling or ridges oc irring in the felted layer, thereby making the product more acceptable to the patient. The second layer provides a cushioning effect which reduces pressure impact on the skin by reducing corrugations in the product. This results in greater user comfort and lessens d e risk of skin abrasion caused by corrugations and creases.

The lifetime of the product is greatly increased due to die increased tensile strength of the product. The increased tensile strength of the product is at least partially due to the thermal treatment applied to the needled layers. The thermal treatment bonds the fibres together thereby reducing the possibility of fibre loss during laundering. The increased lifetime of the product is particularly important to purchasers, whether on a commercial or individual scale, as it ensures that the product may be washed frequentiy without damage thereof.

The embodiments have been described byway of example only and modifications are possible within the scope of the invention.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. An absorbent assembly comprising: a first layer made from a substantially non-absorbent fluid permeable material; a second layer below said first layer, said second layer comprising a substantially non-absorbent material; and a third layer below said second layer, said third layer comprising fibres of hydrophihc and hydrophobic materials needled together so as to form a felt.

2. An absorbent assembly according to claim 1 wherein the first, second and diird layers are quilted together.

3. An absorbent assembly according to claim 2 wherein the material of the second layer serves to plump out spaces formed between the first and diird layers.

4. An absorbent assembly according to any one of the preceding claims wherein the first layer is formed from a brushed polyester material.

5. An absorbent assembly according to any one of the preceding claims wherein the second layer is formed from a 100% polyester fibrofill or fibrous web material.

6. An absorbent assembly according to claim 5 wherein the fibrofill or fibrous web material has a density in die range 50 to 150 g/m².

7. An absorbent assembly according to claim 5 or 6 wherein the fibres of the second layer are of a denier in the range 2 to 13.

8. An absorbent assembly according to any one of the preceding claims wherein the third layer comprises a mix of polyester and rayon fibres.

9. An absorbent assembly according to claim 8 wherein the mix of the third layer is a 50/50% polyester and rayon mix

10. An absorbent assembly according to any one of the preceding claims wherein the third layer is manufactured by needling the hydrophihc and hydrophobic materials together and then subjecting the needled materials to a thermal treatment so as to cause bonding between the hydrophilic and hydrophobic materials.

11. An absorbent assembly according to claim 10 wherein the tiiermal treatment comprises heating the needled third layer in a heat press.

12. An absorbent assembly according to claim 10 or claim 11 wherein the thermal treatment occurs at a temperature in the range of 130 and 200°C.

13. An absorbent assembly according to any one of the preceding claims further comprising a fourth layer below the third layer.

14. An absorbent assembly according to claim 13 wherein the fourth layer is made of a fluid impermeable material so as to prevent fluid leakage from the assembly.

15. An absorbent assembly according to claim 14 wherein the fourth layer is made from a nylon material with a polyurethane backing coat or a polyester material with a polyurethane backing coat.

16. An absorbent bed sheet, bed pad, pillow, undeφants, nappy or die like made from an absorbent assembly according to any one of the preceding claims.

17. An absorbent assembly substantially as hereinbefore described with reference to the accompanying drawings and/or die Examples.