ABSORBENT PRODUCT COMPRISING A NONWOVEN MATERIAL
20170367906 · 2017-12-28
Assignee
Inventors
Cpc classification
A61F13/49473
HUMAN NECESSITIES
A61F13/535
HUMAN NECESSITIES
A61F13/49017
HUMAN NECESSITIES
International classification
A61F13/535
HUMAN NECESSITIES
A61F13/511
HUMAN NECESSITIES
Abstract
An absorbent product includes a nonwoven material arranged to be in contact with skin of a user during use of the absorbent product. The nonwoven material includes, at least on a skin contacting surface, a mixture of non-absorbent and absorbent fibres. The absorbent fibres are present in an amount of 2-30% by weight, or about 2-10% by weight, based on the total weight of the fibres in the nonwoven material. The non-absorbent fibres have a coarseness of 1.8 to 10 dtex and the absorbent fibres have a coarseness of 1 to 10. Also disclosed is a use of a nonwoven material in an absorbent product to reduce wet friction between the nonwoven and skin of a user.
Claims
1. Absorbent product (8; 12, 16; 22; 25) comprising a nonwoven material (1) arranged to be in contact with skin of a user during use of the absorbent product (8; 12, 16; 22; 25), wherein the nonwoven material (1) comprises at least on a skin contacting surface a mixture of non-absorbent and absorbent fibres, wherein the absorbent fibres are present in an amount of 2-30% by weight, preferably about 2-10% by weight, based on the total weight of the fibres in the nonwoven material (1), and wherein the non-absorbent fibres have a coarseness of 1.8 to 10 dtex and the absorbent fibres have a coarseness of 1 to 10 dtex.
2. Absorbent product (8; 12, 16; 22; 25) according to claim 1, wherein the non-absorbent fibres have a coarseness of 2 to 7 dtex or 3.5 to 7 dtex, or 5.5 to 7 dtex.
3. Absorbent product (8; 12, 16; 22; 25) according to claim 1 or 2, wherein the absorbent fibres have a coarseness of 1.1 to 7 dtex or 1.2 to 3 dtex.
4. Absorbent product (8; 12, 16; 22; 25) according to any of the preceding claims, wherein the nonwoven material (1) comprises spunbond, air laid, wet laid, carded, electro spun or meltblown nonwoven, or any combination thereof.
5. Absorbent product (8; 12, 16; 22; 25) according to any one of the preceding claims, wherein the nonwoven material (1) has a basis weight from 8 to 80 g/m.sup.2.
6. Absorbent product (8; 12, 16; 22; 25) according to any one of the preceding claims, wherein the thickness of the nonwoven material (1) is from 0.1-3 mm.
7. Absorbent product (8; 12, 16; 22; 25) according to any one of the preceding claims, wherein the absorbent fibres comprise cellulosic fibres.
8. Absorbent product (8; 12, 16; 22; 25) according to any one of the preceding claims, wherein the non-absorbent fibres comprise synthetic fibres.
9. Absorbent product (8; 12, 16; 22; 25) according to any one of the preceding claims, wherein the absorbent product (8; 12, 16; 22; 25) is a diaper, incontinence protection garment, sanitary napkin or panty liner.
10. Absorbent product (16; 22; 25) according to any one of the preceding claims, wherein the absorbent product (16; 22; 25) comprises a chassis (26) having a front and rear panel (17, 19) and an absorbent body (11) having a wetting zone for receiving urine and other bodily fluids, wherein the nonwoven material (1) at least is comprised in a region outside the wetting zone in the absorbent body (11) for receiving urine and other bodily fluids.
11. Absorbent product (8; 12, 16; 22; 25) according to claim 10, wherein the nonwoven material (1) at least is comprised in a region outside the absorbent body (11).
12. Absorbent product (16; 22; 25) according to any one of claim 9, 10 or 11, wherein the absorbent product (16; 22; 25) comprises a waist region, hip region, standing gathers, leg openings and belt, and the nonwoven material (1) is comprised in at least one of the waist region, hip region, standing gathers, leg openings and belt.
13. Absorbent product (25) according to claim 12, wherein the belt is attached to the chassis or the belt is separate from the chassis arranged to be attachable to the chassis, wherein the nonwoven is comprised in the belt on a side of the belt being arranged to be in contact with skin.
14. Absorbent product (8; 12; 16; 22; 25) according to any one of claims 8-13, wherein the absorbent product (8; 12; 16; 22; 25) comprises a topsheet (9), an absorbent body (11) and a backsheet (10), and wherein the nonwoven material (1) is comprised in the topsheet (9) and/or the backsheet (10) of the absorbent product (8; 12; 16; 22; 25).
15. Absorbent product (8; 12; 16; 22; 25) according to any one of the preceding claims, wherein the nonwoven material (1) has lower friction values in the presence of moisture, than a nonwoven material consisting of non-absorbent fibres having a finer coarseness than 1.8 dtex and absorbent fibres having a finer coarseness than 1 dtex , measured by means of a curve obtained in repeated runs with measurements according to a repeated stick and slip method described in the description, wherein the friction values in the curve are obtained in repeated runs and wherein the curve comprises a first slope having a positive coefficient illustrating increase in the friction values, a plateau, and a second slope having a negative coefficient illustrating decrease in the friction values.
16. Absorbent product (8; 12; 16; 22; 25) comprising a nonwoven material (1) arranged to be in contact with skin of a user during use of the absorbent product (8; 12; 16; 22; 25), wherein the nonwoven material (1) has lower friction values in presence of moisture, measured along a curve obtained in repeated runs with measurements according to a repeated stick and slip method described in the description, than a nonwoven material consisting of non-absorbent fibres having a finer coarseness than 1.8 dtex and absorbent fibres having a finer coarseness than 1 dtex, wherein the friction values are obtained in repeated runs and wherein the obtained friction values during the run form the curve comprising a first slope having a positive coefficient illustrating increase in the friction values, a plateau, and a second slope having a negative coefficient illustrating decrease in the friction values.
17. Absorbent product (8; 12; 16; 22; 25) comprising a nonwoven material (1) arranged to be in contact with skin of a user during use of the absorbent product (8; 12; 16; 22; 25), wherein the nonwoven material (1) has lower maximum friction value in presence of moisture, measured along a curve obtained in repeated runs with measurements according to a repeated stick and slip method described in the description, than a nonwoven material consisting of non-absorbent fibres having a finer coarseness than 1.8 dtex and absorbent fibres having a finer thickness than 1 dtex.
18. Use of a nonwoven material (1) in an absorbent or hygiene product to reduce wet friction between the nonwoven material (1) and skin of a user, the nonwoven material (1) comprising a mixture of non-absorbent and absorbent fibres, wherein the absorbent fibres are present in an amount of 2-30% by weight, preferably about 2-10% by weight, based on the total weight of the fibres in the nonwoven material (1), and wherein the non-absorbent fibres having a coarseness of 1.8 to 10 dtex and the absorbent fibres have a coarseness of from 1 to 10 dtex.
19. Use according to claim 18, wherein the wet friction is measured between the surface of the nonwoven and skin of a user of the absorbent product (8; 12; 16; 22; 25) by a repeated stick and slip method described in the description.
20. Use according to any one of claims 18 and 19, wherein the nonwoven material (1) is used in an absorbent product (8; 12; 16; 22; 25) chosen from a diaper, incontinence protection garment, sanitary napkin or panty shield.
21. Use according to claim 20, wherein the nonwoven material (1) is used in substantially non-absorbent regions of the absorbent product (8; 12; 16; 22; 25).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0036]
[0037]
[0038]
[0039]
[0040]
[0041]
[0042]
[0043]
[0044]
[0045]
DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS
[0046] As used herein, the term “absorbent product” means a product that absorbs or is adapted to absorb bodily fluids, such as urine and/or blood. The absorbent product is wearable by a user and, as used herein, the term “wearable absorbent product” means an absorbent article which is to be worn by the user, such as a diaper, pant-type diaper, sanitary napkin, panty-liner or incontinence product.
[0047] As used herein, the term “absorbent fibre” means a fibre having the ability to absorb liquid, such as at least 1 g liquid/1 g fibres. The fibre also has moisture buffering capacity and is defined as hygroscopic.
[0048] As used herein, the term “non-absorbent fibre” means a fibre with substantially no absorption capacity.
[0049] The nonwoven material layers or webs may advantageously be selected from, for example, of spunbond, air laid, wet laid, carded, electro spunned or meltblown nonwovens. The nonwoven material may be bonded by multiple techniques, e.g. by needling, hydroentangling, or heat bonding.
[0050] The nonwoven material of the disclosed products is a mixture of natural and synthetic materials. Natural fibres are for instance cellulosic fibres or fibres from regenerated cellulose. In certain embodiments, the absorbent fibres are based on cellulose including regenerated cellulose fibres such as viscose and/or lyocell fibres which are nontoxic. The non-absorbent fibres may include synthetic fibres, such as polyolefin-based fibres, for example fibres of polypropylene (PP) or polyethylene (PE). The synthetic fibres may be of any commercially available type and can be obtained e.g. by extrusion.
[0051] The nonwoven material may be a combination of several types of nonwoven materials, such as spunbond-meltblown, spunbond-meltblown-spunbond (SMS) type or spunbond-meltblown-meltblown-spunbond (SMMS) type. In some embodiments were there are several layers of nonwoven laminated by means of gluing or by ultrasound, only the nonwoven layer lying against the skin is the nonwoven material referred to in the description.
[0052] The basis weight for the nonwoven material can be varied of from 8 to 80 g/m.sup.2, from 8 to 40 g/m.sup.2, and or from 8 to 30 g/m.sup.2. When the basis weight is under 40 g/m.sup.2, sufficient breathability, drapeability and comfort for the product can be obtained. The basis weight of from 8 to 30 g/m.sup.2 has been found to provide best comfort and flexibility while processability of the material is still good.
[0053]
Stick and Slip Measurement Method for Measuring the Wet Friction
[0054] The method measures the static friction, sns value (stick and slip value) in gram force, gmf, between a material and the human skin. The method means that repeatedly runs are made using the same material strip. First the sns value for the dry state (dry material and skin) is measured followed by wet state at different liquid levels (from completely wetted material, to moist and to almost dry) until the sns value is back to the skin-material interaction level measured in the first dry run, which means that the material is dry again. The method is thus called a repeated stick and slip method or sns run dry-wet-dry.
Definition of the Method
[0055] As used herein, the “stick and slip value” is defined as the point on the force curve (gmf) where the material starts gliding over the arm. The sns values from all single force curves are then put together in a new graph, sns values as a function of number of runs.
Principle of the Method
[0056] A strip 110 of test material is pulled, with the help of a MTT 170 tensile tester 120, across the volar forearm 100 to measure the static friction between the material and the skin as illustrated in
Equipment of Method
[0057] Test person's arm, volar forearm
[0058] The test person is acclimatized during 15 min in a climate room with 21° C. and 45%rh.
[0059] The test is performed in a climate room with 21 ° C. and 45%rh
[0060] MTT 170 tensile tester from DiaStron
[0061] Adjustable armrest channel
[0062] Software MTT Win (UvWin 1.32.000)
[0063] Clamp 1: on the tensile tester
[0064] Clamp 2: counter weight, 60 g
[0065] 0.9 weight % NaCl solution (150 ml/material strip)
[0066] Punch, 30*350 mm
Material
[0067] The material to be tested is punched or made into rectangular strips measuring 30×350 mm. When testing, the treated side, i.e. the side of the nonwoven having claimed properties, is placed towards the skin.
Wetting of the Material Strip
[0068] The material strip is completely wetted by submerging the whole strip in a beaker of 0.9 weight % NaCl solution (150 ml) for 1 min. The strip is lifted in the edge that will be placed in the clamp of the tensile tester using a pair of tweezers. The clamp of the tensile tester is illustrated in
[0069] The sns runs with the wet strip are then tested in the same way as the first run.
Start Procedure
[0070] The computer and control unit are turned on and the instrument and program is initialized and is in the ready to start mode.
[0071] Delay time is for every friction measurement 12 seconds to give time to zero the load and place the material strip in the right position on the arm before the run begins.
[0072] If a material strip has not reached its slip value after 50 mm the distance needs to be increased.
Positioning of Test Persons Arm
[0073] The test person should be standing close to the instrument with the arm supported comfortably in the armrest channel. The armrest channel is adjusted so that the top of the volar forearm is in level with the clamp on the tensile tester. This means that the material strip is horizontal between the clamp and arm. During measurements, the arm should be kept still and relaxed.
Performing the Test
[0074] The dry nonwoven strip is placed in the clamp on the tensile tester and the 60 g counter weight is fastened in the other edge of the strip.
[0075] The test persons arm should be correctly placed in the armrest channel as described according to “Positioning of test persons arm”.
[0076] The test is started. The first seconds of the delay time is used to zero the measurement, lift the nonwoven strip from the arm and hold the counter weight so that there is no tension on the tensile tester. The nonwoven strip is then hung over the relaxed arm and the counter weight should be still. The sns run starts directly when the delay time of 12 sec. is finished.
[0077] The load cell travels the pre-set distance (50 mm) at a certain speed (150 mm/min) and pulls the nonwoven strip over the aim and when it stops the sns value is noted. The so called sns value, which is where the material no longer “sticks” to the skin and starts to glide, is noted for every repetition.
[0078] Let the tensile tester go back to the start position.
[0079] The same nonwoven strip is then submerged in a bath of 0.9% NaCl solution for 1 min, see instructions about “Wetting of material strip”. The wet nonwoven strip is then attached to the clamp on the tensile tester exactly as for the first run with the counterweight in the edge and the arm in the same position. The friction measurement is started in the same way as the first run and the sns value from the friction curve for the second run is noted.
[0080] Then the nonwoven strip is lifted away from the arm, without touching anything, while the tensile tester goes back to its start position. When back at the start position the next run will be started, in the same way as for the first run and as soon as possible, and the third sns value is noted. The test continues like this until the sns value is on the same level as the first run.
Calculation and Expression of Results
[0081] The sns value from each run is noted (gmf) and a graph showing the repeated sns values (gmf) is made, sns values as a function of number of runs.
[0082] Returning to the nonwoven material, the nonwoven material with a mixture of non-absorbent and absorbent fibres and wherein the non-absorbent fibres have a coarseness of 1.8 to 10 dtex and the absorbent fibres have a coarseness of 1 to 10 dtex is represented by second curve 7 in
[0083] The curves start at a value corresponding to the dry friction measured for dry nonwoven. The positive coefficient of the first slope 6a, 7a indicates an increase in friction when the dry nonwoven is wetted and wet friction occurs. The second slope 6c, 7c illustrates the interface between the skin and nonwoven returning the friction curve to the value of dry friction. As can be seen from
[0084] For some materials, a very clear peak can be seen in a curve of friction values. As indicated by references 6d and 7d in
[0085]
[0086] The total frictional force in a system involving moisture is the sum of the dry force (F_dry) and the clinging force (F_clinging):
F_friction=F_dry+F_clinging (Eq. 1)
[0087] Normally F_dry<<F_clinging. The clinging force can be further divided into contributions arising from wet contacts and wet pores:
F_clinging =F_wet contacts+F_wet pores (Eq. 2)
[0088] In reality, the frictional force is a mixture of all three interactions occurring in different numbers as described by equation 3:
F_friction(s)=F_dry×C_dry+F_wet contacts×C_wet contacts(s)++F_wet pores×C_wet pores(s) (Eq.3)
where s is the degree of saturation at the interface and C is the occurrence of interactions.
[0089] When the material is wetted, the force from wet pores provides the substantial contribution to the wet friction. The wet pore force rapidly increases the friction as seen by the positive coefficient of first slope 6a, 7a of curve. The material slowly dries over the next runs. Over these runs the force from the wet pores still provides the greatest contribution to the friction force. This is indicated by the plateau 6b, 7b. As the material dries further, the force from the wet contacts provides a sharp rise in the friction force, as indicated by the sharp increase of friction of peak 6d, 7d. After the peak 6d, 7d is reached, the material dries further reducing the number of wet contacts. This quickly returns the curve to the dry friction value. This is seen by the negative coefficient of second slope 6c, 7c. In some situations, there will be no peak 6d, 7d which is visible in measurements.
[0090]
TABLE-US-00001 gsm dtex polymer technology Material A 15 1.5 PE/PP SC Spunbond Material B 17 1.4 PP Spunbond Material C 17 3.6 PP Spunbond Material D 17 6.5 PP Spunbond Material E 18 3.3 PP Carded Material F 18 3.3 PP Carded 1.7 2% Viscose
[0091] Material A, B, C, D and E are made of 100 weight percent of non-absorbent fibers and material F is made of 98 weight percent non-absorbent fibers (polypropylene) and 2 weight percent absorbent fibers (viscose fibers). PE is polyethylene and PP is polypropylene. Material A is a bicomponent fiber of polyethylene and polypropylene and SC stands for sheath/core.
[0092] Looking at
[0093] In
[0094]
[0095] As regards the carded materials in
[0096] The absorbent body may in any conventional material suitable for absorbing discharged bodily wastes, such as cellulosic fluff pulp, tissue layers, highly absorbent polymers (superabsorbents), absorbent foam materials including hydrogel-foam material, absorbent nonwoven materials or the like.
[0097] Generally, the liquid permeable topsheet comprises or consist of a nonwoven material. The topsheet material may further be composed of tow fibres, porous foams, apertured plastic films etc. As mentioned above, the materials suited as topsheet materials should be soft and non-irritating to the skin and be readily penetrated by body fluid, e.g. urine or menstrual fluid, and display low rewetting properties.
[0098] The liquid impermeable backsheet may comprise or consist of a thin plastic film, e.g. a polyethylene or polypropylene film, a nonwoven material coated with a liquid impervious material, a hydrophobic nonwoven material which resists liquid penetration or laminates of plastic films and nonwoven materials. The backsheet material may be breathable so as to allow vapour to escape from the absorbent body, while still preventing liquids from passing through the backsheet material.
[0099] The topsheet and backsheet may be connected to each other for example by adhesive bonding, gluing or welding by heat or ultrasonic. The topsheet and/or the backsheet may further be attached to the absorbent body by any method known in the art, such as adhesive, heat-bonding etc.
[0100] Below follows a number of examples of absorbent products comprising a nonwoven material. The absorbent products are wearable absorbent products. Features of the absorbent articles shared between the products have the same reference numbers. In accordance with embodiments of the present invention, the absorbent product, i.e. for example a conventional diaper, belted absorbent product or pant type diaper or any other absorbent product, includes at least one region comprising the nonwoven as described earlier. The region can at least partially include a waist region and/or a hip region of the absorbent product to provide comfort and fit around the waist. The hip region is defined as the region below the waist region and above the crotch region. It includes the hips, the abdominal region and the lower part of the back and the upper parts of the buttocks that are at the same height as the hips. The region may also be a leg structure in the crotch region, whereby the nonwoven can provide a reduced friction against the skin of the user when the contact surface includes moisture. The nonwoven may also constitute at least a part of a standing gather structure in the crotch region of the absorbent product or it can be a part of a crotch elastic structure in the crotch region. The crotch elastic structure serves i.e. to encourage the absorbent product to adopt a bowl shape in the crotch region when the product is worn to thereby assist in retaining discharged bodily wastes.
[0101] The nonwoven is especially suitable to be used at regions outside an initial wetting zone or landing zone of the absorbent products. This means that the nonwoven may at least partially cover the absorbent structure, but can be located outside the initial wetting zone or landing zone, i.e. an area in the crotch portion to which urine initially lands.
[0102]
[0103]
[0104]
[0105]
[0106]
[0107] The above description defines examples of embodiments of the present invention but the examples are not to be regarded as limiting the invention in any way. The invention may be varied within the scope of the appended claims.
TABLE-US-00002 APPENDIX 1 Test results for nonwoven with non-absorbent fibres having different coarseness Sample A1 A2 B1 B2 C1 C2 D1 D2 No. of gmf gmf gmf gmf gmf gmf gmf gmf 1 118 113 133 113 126 125 142 133 2 362 667 396 513 430 493 324 382 3 412 714 460 627 466 565 373 433 4 459 702 508 679 490 621 396 459 5 503 700 529 709 501 634 408 466 6 543 735 526 706 513 651 424 475 7 573 715 539 731 531 659 413 453 8 608 769 535 729 576 644 414 493 9 629 834 542 722 581 652 406 515 10 637 795 507 667 609 620 402 527 11 640 794 493 652 600 635 429 534 12 693 756 491 639 506 635 428 618 13 704 706 486 639 364 653 318 675 14 755 724 473 584 289 751 210 456 15 766 667 468 565 240 786 192 272 16 760 685 488 594 191 444 159 195 17 706 701 544 786 151 280 147 161 18 661 700 509 560 136 184 141 150 19 557 557 313 205 127 157 133 20 471 529 258 142 124 140 140 21 186 436 204 127 124 143 134 22 119 355 168 118 127 23 216 144 116 123 24 169 136 111 25 116
TABLE-US-00003 APPENDIX 2 Test results for nonwoven having only non-absorbent fibres and nonwoven with a mixture of non-absorbent fibres and absorbent fibres Sample E1 E2 E3 E4 E5 F1 F2 F3 No. of runs gmf gmf gmf gmf gmf gmf gmf gmf 1 135 154 134 126 134 151 132 139 2 353 434 383 309 445 208 239 279 3 409 527 446 353 543 148 217 264 4 464 579 472 383 610 150 214 253 5 495 617 505 417 627 157 227 260 6 520 628 548 461 643 163 232 261 7 527 673 567 463 669 168 244 261 8 556 706 594 473 675 176 244 256 9 603 756 600 485 677 182 263 263 10 591 744 630 503 692 184 259 278 11 602 756 627 505 705 187 272 269 12 552 745 610 498 690 191 261 263 13 558 758 609 499 684 190 260 272 14 569 759 621 468 673 192 259 277 15 602 744 646 505 651 194 258 271 16 482 753 634 495 614 191 255 279 17 342 732 606 487 645 189 261 273 18 238 743 609 487 647 208 280 276 19 186 557 592 506 647 214 289 295 20 156 383 593 516 671 254 292 305 21 140 263 574 506 724 267 326 333 22 139 165 590 484 753 244 345 350 23 144 144 602 355 526 224 336 380 24 132 576 250 320 177 212 394 25 137 574 202 244 148 165 341 26 416 154 200 144 142 258 27 310 139 176 135 207 28 185 133 156 130 186 29 152 144 128 156 30 139 133 144 31 136 140 32 137 33 132