JP-7855517-B2 - Elastomer laminate having a control layer and method thereof

Inventors

• トッド、エル．マンスフィールド
• ロバート、ハインズ、ターナー

Assignees

• ザ プロクター アンド ギャンブル カンパニー

Dates

Publication Date

20260508

Application Date

20210308

Priority Date

20200309

Claims (15)

1. A disposable absorbent article in the form of a diaper or absorbent pants, comprising a liquid-permeable top sheet (138), a liquid-impermeable back sheet (136), and an absorbent core (140) disposed between the liquid-permeable top sheet (138) and the liquid-impermeable back sheet (136), The elastomer laminate (302) comprises a plurality of elastic strands (318) spaced apart from each other and bonded to a nonwoven web material (306) by an adhesive (350), The elastic strand (318) comprises a strand polymer, and the strand polymer has a solubility parameter in the range of 18 MPa 1/2 to 18.5 MPa 1/2 . The adhesive (350) comprises an adhesive polymer, and the adhesive polymer has a solubility parameter in the range of 16 MPa 1/2 to 17.5 MPa 1/2 . The elastic strand (318) and/or the adhesive (350) includes a control layer, the control layer having a solubility parameter in the range of 15.5 MPa 1/2 to 16.5 MPa 1/2 and a number-average molecular weight in the range of 0.6 kg/mol to 1.5 kg/mol. The elastic strand is a disposable absorbent article having an average Dtex of 10 to 500 .
2. The disposable absorbent article according to claim 1, wherein the number-average molecular weight of the control layer is lower than the molecular weight of the strand polymer and the adhesive polymer, respectively.
3. The disposable absorbent article according to claim 1 or 2, wherein the χN value between the control layer and the strand polymer is greater than 2, and the χN value between the control layer and the adhesive polymer is less than 2, where N is the degree of polymerization of the control layer and χ is the Florey-Huggins interaction parameter.
4. The disposable absorbent article according to any one of claims 1 to 3, wherein the strand polymer has a solubility parameter of 18.3 MPa 1/2 .
5. The disposable absorbent article according to any one of claims 1 to 4, wherein when the elastomer laminate is subjected to a laminate creep test, the elastomer laminate has a laminate creep of 5 mm or less.
6. The disposable absorbent article according to any one of claims 1 to 5, wherein the elastomer laminate has a static peel force time of 700 minutes/10 mm or more.
7. The disposable absorbent article according to any one of claims 1 to 6, wherein the adhesive at 38°C has a flat portion elastic modulus of 0.1 MPa at 38°C and 1 Hz.
8. A disposable absorbent article according to any one of claims 1 to 7, wherein the tensile modulus of the elastic strand at room temperature is in the range of 5 MPa to 15 MPa.
9. The disposable absorbent article according to any one of claims 1 to 8, wherein the elastomer laminate containing the elastic strands forms at least a portion of a disposable article component selected from the group consisting of a belt, ear portion, side panel, cuff, waistband, back sheet, and top sheet.
10. The disposable absorbent article according to any one of claims 1 to 9, wherein the control layer is mineral oil.
11. The disposable absorbent article according to claim 10, wherein the mineral oil is a paraffinic mineral oil.
12. The disposable absorbent article according to any one of claims 1 to 9, wherein the control layer comprises white mineral oil, polyisoprene, and polybutadiene.
13. The disposable absorbent article according to any one of claims 1 to 9, wherein the control layer is a synthetic oil.
14. The disposable absorbent article according to any one of claims 1 to 13, wherein the control layer contains soap, and the soap is magnesium stearate.
15. The disposable absorbent article according to any one of claims 1 to 14, wherein the strand polymer comprises segmented polyurethane, and the adhesive polymer comprises a styrene-based block copolymer.

Description

This disclosure relates to absorbent articles having elastomer laminates, and more specifically, to adhesives, control layers, and elastic strands for elastomer laminates. Various types of articles, such as diapers and other absorbent articles, can be assembled by adding components to a continuous web of material along an assembly line, and/or by processing the continuous web of material in other ways. For example, in some processes, a web of material is combined with another web of material. In other examples, individual components made from a web of material are combined with a web of material, and then these are combined with another web of material. In some examples, individual components made from one or more webs of material are combined with other individual components made from other webs of material. The webs and components of material used to manufacture diapers may include a backsheet, a topsheet, leg cuffs, a waistband, absorbent core components, front and/or rear ear sections, fastening components, and various types of elastic webs and components such as leg elastics, barrier leg cuff elastics, stretch side panels, and waist elastics. Once the desired component parts are assembled, the advancing web and component parts are subjected to a final knife cut to separate the web into individual diapers or other absorbent materials. Some absorbent articles have components including an elastomer laminate. Such an elastomer laminate may include an elastic material bonded to one or more nonwoven fabrics. The elastic material may include an elastic film and/or elastic strands. In some laminates, when multiple strands are stretched, they bond together to form a nonwoven fabric. As a result, when the elastic strands relax, the nonwoven fabric forms folds between the points of contact with the elastic strands, thereby creating a corrugated shape. The resulting elastomer laminate is stretchable to the extent that the elastic strands can be stretched by the corrugation. In some assembly processes, stretched elastic strands may be advanced in the mechanical direction and bonded between two advancing substrates, with the stretched elastic strands spaced apart transversely. Some assembly processes also utilize several elastic strands spaced very close together transversely. In some configurations, the close transverse spacing between elastic strands can be achieved by drawing the elastic strands from windings stacked transversely on a beam. For example, various fiber manufacturers can utilize beam elastic materials and associated handling equipment, such as those available from Karl Mayer Corporation. However, problems can arise in the manufacturing process when using elastic strands laminated on a beam. For example, elastic strands on a beam are prone to blocking when drawn from the beam due to bridging between strands caused by the high compression of the beam over a considerable storage life. To prevent blocking in elastic strands, they can be treated with silicone oil or other types of spin finish. While applying a spin finish to the beam can reduce the likelihood of blocking, spin finish can have undesirable effects on the manufacturing process. For example, when elastic strands are formed in an elastomer laminate and an adhesive is used to bond the strands to the nonwoven layer, spin finish can negatively affect the effectiveness of the adhesive. A relatively large amount of adhesive may be required to achieve the desired level of adhesion. Using a large amount of adhesive is undesirable because it increases the cost of materials and results in a rigid laminate that does not have the desired appearance or performance for incorporation into absorbent articles. This is a front view perspective of a diaper pants.This is a rear perspective view of a diaper pants.These are partial cut-out plan views of the diaper pants shown in Figures 1A and 1B, in a flat, non-shrinkable state.This is a cross-sectional view of the diaper pants shown in Figure 2, along line 3A-3A.This is a cross-sectional view of the diaper pants shown in Figure 2, along line 3B-3B.This is a schematic side view of a processing apparatus adapted to manufacture an elastomer laminate including a first plurality of elastic strands positioned between a first substrate and a second substrate.This is a diagram of the processing apparatus shown in Figure 4, along line 5-5.An example of a beam in the sky is shown.The adhesion of the elastic strand to the first substrate is schematically shown.This diagram schematically illustrates the time-dependent interactions between multiple elastic strands, adhesives, and a control layer during the manufacturing of an elastomer laminate.This shows a creep test of a laminated structure.This shows a creep test of a laminated structure.This shows a creep test of a laminated structure. The following glossary of terms may be useful in understanding this disclosure. In this specification, “absorbent article” is used to re