Absorbent structure comprising an oil-scavenger component
An absorbent structure comprising absorbent polymer particles supported by a substrate layer and immobilized on this substrate layer by a thermoplastic adhesive material and further comprising a component sorbing oily substances that may migrate from the thermoplastic adhesive material is disclosed. The absorbent structure can be suitably incorporated in a disposable absorbent article.
1. An absorbent structure for use in disposable absorbent articles comprising:
(a) a substrate layer,
(b) absorbent polymer particles supported by said substrate layer,
(c) a thermoplastic adhesive material comprising one or more oily substances, said thermoplastic adhesive material immobilizing said absorbent polymer particles on said substrate layer,
(d) a particulate, single oil-scavenger component contacting said absorbent polymer particles and said thermoplastic adhesive material;
wherein the oil-scavenger component is a monomer selected from the group consisting of an aliphatic mono- or dihydric alcohol having at least 12 carbon atoms and an aliphatic mono- or dicarboxylic acid having at least 12 carbon atoms;
wherein the particulate, single oil-scavenger component is deposited exclusively on or beneath the absorbent polymer particles.
2. The absorbent structure according to claim 1 wherein said absorbent structure comprises less than 5% by weight of cellulose.
3. The absorbent structure according to claim 1 or 2 wherein the absorbent polymer particles, thermoplastic adhesive material comprising one or more oily substances and the oil-scavenger component in combination exhibits a ratio (AI oilscavenger /AI control )>1 as measured according to the Absorption Index Method.
4. The absorbent structure according to claim 1 wherein the weight ratio of the absorbent polymer particles to the oil-scavenger component is from 2:1 to 1000:1.
5. The absorbent structure according to claim 1 , wherein said absorbent structure further comprises a cover layer covering said absorbent polymeric particles, oil-scavenger component and thermoplastic adhesive material.
6. The absorbent structure according to claim 1 , wherein said aliphatic mono- or dihydric alcohol is selected from the group consisting of 1-octadecanol, 1,2-dodecanediol, 1,2-hexadecanediol, 1-tetradecanol, 1,2-tetradecanediol, 1,14-tetradecanediol, 1,2-octadecanediol, and 1,12-octadecanediol.
7. The absorbent structure according to claim 1 , wherein said aliphatic mono- or dicarboxylic acid is selected from the group consisting of dodecanoic acid, octadecanoic acid, hexadecanedioic acid, tetradecanoic acid, and tetradecanedioic acid.
8. The absorbent structure according to claim 1 , wherein the substrate layer is selected from the group consisting of nonwoven material, foam and film.
9. The absorbent structure according to claim 1 , wherein said oil-scavenger component is in particulate form and has an average particle size of from 0.005 μm to 5 mm.
10. A disposable absorbent article comprising an absorbent structure according to claim 1 , wherein said disposable absorbent article is selected from the group consisting of diapers, incontinence pads, sanitary napkins and panty-liners.
11. A process for making an absorbent structure according to claim 1 comprising the steps of:
(a) providing a substrate layer,
(b) providing absorbent polymer particles,
(c) providing a thermoplastic adhesive material comprising one or more oily substances,
(d) providing an oil-scavenger component in particulate form, wherein the oil-scavenger component is a monomer selected from the group consisting of an aliphatic mono- or dihydric alcohol having at least 12 carbon atoms and an aliphatic mono- or dicarboxylic acid having at least 12 carbon atoms, and
(e) depositing the absorbent polymer particles on the substrate layer, depositing the oil-scavenger particles exclusively on the absorbent polymer particles and depositing the thermoplastic adhesive material on the oil-scavenger particles.
12. The process according to claim 11 further comprising the step of depositing a further thermoplastic adhesive material on the substrate layer prior to step (e).
13. The process according to claim 11 or 12 wherein it further comprises the steps of providing a cover layer and disposing said cover layer over said absorbent polymer particles, oil-scavenger component and thermoplastic adhesive material.
14. The process according to claim 11 comprising the steps of repeating at least once steps (a) to (e) to obtain a further absorbent structure and combining the absorbent structures to obtain an absorbent core comprising several absorbent structures.