Biobased Super-Absorbing Polymers

Abstract

The present invention is in the field of extraction a product for liquid absorption comprising a low-density biopolymer, such as obtainable from a granular sludge, in particular alginate or bacterial alginate, wherein the biobased polymer acts as a super-absorbing material, and a method of obtaining said product.

Claims

1-23. (canceled)

24. A product for liquid absorption comprising: a super-absorbing material of biobased polymer, wherein the biobased polymer is produced by a microorganism selected from bacteria, algae and fungi, comprising 20-99.8 wt. % low density polymer material, with a density <0.5 gr/cm3, wherein the super-absorbing biobased polymer material is a non-woven material, and/or wherein the super-absorbing biobased polymer material comprises fibres, and/or wherein the super-absorbing biobased polymer material comprises a powder with particle sizes >0.1 mm, 0-80 wt. % fillers, 0-10 wt. % cross-linking agent, 0-30 wt. % water-soluble polymer, 0-2 wt. % buffer, 0-2 wt. % additive, 0-5 wt. % lipids, and the remainder being water, wherein all percentages are relative to a total weight of the super-absorbing material.

25. The product according to claim 24, wherein the product is selected from a diaper, an incontinence product, concrete, a personal hygiene product, a soil-improver, a water retainer, a wound dressing, a liquid absorbent, a thermal insulator, a thermal clothing layer, a thermal insulating panel, a protective sheet or laminate, a filter, and an absorbent pan component.

26. The product according to claim 24, wherein the biobased polymer is produced by a microorganism, selected from the order Pseudomonadaceae, the order Planctomycetales, and algae, and the biobased polymer is alginate.

27. The product according to claim 24, wherein the super-absorbing biobased polymer is immobilized in the product.

28. The product according to claim 24, wherein the super-absorbing biobased polymer is treated by at least one of cross-linking, with nanoparticles, by radiation branching, by chemical modification, by physical modification, by surface modification, and by providing a shell.

29. The product according to claim 24, wherein the super-absorbing biobased polymer comprises fibres with a diameter of 1-100 μm, a length of 0.1-5 mm, and a mesh of 1-2000 μm, and/or having an absorbing capacity of >20 (wt./wt.), and/or wherein the biobased polymer has a core-shell structure, and/or wherein the fibrous biobased polymer is at least one of spun, weaved, felted, needled, and punched.

30. The product according to claim 24, wherein the super-absorbing biobased polymer comprises as monovalent cation NH.sub.4.sup.+ or Na.sup.+, and/or wherein the bacterial alginate (ALE) is bleached.

31. The product according to claim 24, wherein the super-absorbing biobased polymer comprises 10.sup.−5-10.sup.−1 wt. % of a water-miscible non-solvent, and alkoxy alkanols, and alkylene amines.

32. The product according to claim 24, further comprising a chemical compound selected from medicaments, anti-inflammatory agents, soil nutrients, and combinations thereof.

33. The product according to claim 24, wherein the product comprises multiple layers, of which one layer comprises a SAP-material.

34. The product according to claim 24, wherein the product comprises a clay, and/or wherein the product comprises a fire-retardant, and/or wherein the product comprises UV-inhibitors.

35. (canceled)

36. (canceled)

37. (canceled)

38. (canceled)

Description

SUMMARY OF THE FIGURES

[0060] FIG. 1 shows two photos of fibrous alginate obtained by the present process.

[0061] FIG. 2 shows a photo of foamed ALE.

[0062] FIG. 3 shows a photo of granular ALE.

[0063] FIGS. 4a-d show SEM-photos of the present alginate.

[0064] FIG. 5a, b show a SEM-photo of a foamed alginate.

[0065] FIG. 6a-b show the present absorbing capacity (30 g/g).

DETAILED DESCRIPTION OF THE FIGURES

[0066] FIG. 1 shows a cotton-wool like example of the present fibrous alginate after freeze drying. The length is a few centimeters. First (i) a 3% Na-alginate solution in H2O was prepared, (ii) the solution was left to homogenise and some occasional stirring was applied, (iii) thereafter about 50% acetone to the alginate/H.sub.2O solution was added, decant on top and shaken vigorously, (iv) then the supernatant was poured off and replaced with 100% acetone. This was repeated several times. A fibrillar mass of Na-alginate in acetone with a low water content was obtained. Then (v) the moistened fibrillar mass was placed in a freezer and then the solvent was evaporated off in vacuum; thereby a freeze dried Na-alginate fibrillar mass was obtained. The freeze drying procedure is found to prevent the sample from collapsing so the morphology can be investigated more easily. Overall sample size is about 4 cm long, 1 cm diameter.

[0067] FIG. 2 shows a photo of foamed ALE.

[0068] FIG. 3 shows a photo of granular ALE.

[0069] FIGS. 4a-d show SEM photos of the present Na-alginate. Typical fibres obtained are a few (1-2) mm to a few (1-5) cm long having a thickness of 2-250 μm. Small fragments were imaged using a SEM (see scale bars for magnification and SEM settings). Various techniques were used, such as sputtered with Au to prevent charging, and also a backscatter image.

[0070] FIG. 5a, b show SEM-photos of a foamed alginate.

EXAMPLES/EXPERIMENTS

[0071] The invention although described in detailed explanatory context may be best understood in conjunction with the accompanying examples.

[0072] Diaper Comprising ALE

[0073] A diaper, and likewise a sanitary towel or incontinence pad, is made with a 2-ply absorber. Therein a layer for liquid up-take, distribution and intermediate storage layer on the body side in use is provided and a storage layer containing >=50 wt. % super absorbing polymer (ALE) on the other side. The first layer may consist of a thermoplastic polymer, extruded with addition of a blowing agent. In addition a back-side layer may be provided, preferably a liquid impermeable back-sheet. The SAP preferably has a pH<6, such as less than 5.0. In addition additives may be provided, such as absorbents, such as benzoic acid, hydroxybenzoic acid, and esters thereof, which are found to suppress unpleasant odours. In addition to the above materials the absorbent core may comprise, e.g. in admixture, other absorbent materials. Any other suitable absorbent material can be used. Examples include a wide variety of liquid-absorbent materials commonly used in disposable diapers and other absorbent articles such as cellulose based materials, tissues, laminates, foams, sponges, gelling materials, and combinations of materials. Also further fibre materials may be included of natural and synthetic origin, such as cotton. To determine a fluid retention capacity of the superabsorbent material in saline after centrifugation, the standard test EDANA WSP 241.2 is used.

[0074] Wound Dressing

[0075] An example of an alginate antibacterial dressing comprises: 50-90% of super absorbing alginate, 5-50% of beta-cyclodextrin and 0.0-5% of silver ion dispersion liquid. The alginate material supports hydrogen-bond action in molecules.

[0076] Soil Improver

[0077] An example of a soil improver composition 50% ALE is provided therein. The improver may further comprise 2-60% of straw, 1-50% humus, and 1-10% of inorganic salts; the inorganic salts may comprise calcium, magnesium, iron, zinc, boron and nitrogen. The improver is quickly effective and durable; the improver need only be applied for 1 to 2 times. The ALE enhances the permeability of the soil and reduces soil corrosion resistance. It further has a good water retention, and shows slow-release performance for fertilizers. The soil improver may find use as a stabilizer, as fillings, for improving physical-chemical properties, increasing its cementing value, and decreasing its linear expansion and contraction. The present soil improver is especially suited for soils in dry climates (semi-arid and arid) and in continental climates. It is found to reduce water consumption of up to 50%, to limit fertilizer leaching and to improve soil.

[0078] Water Retainer

[0079] An example of a cold retainer composition is 25% ALE, 5% urea, a polyhydric alcohol, and water. The cold retainer composition has an excellent durability of cold retaining effect, can be folded to an applied part and provides softness at a low temperature; it may be used for cooling of strains, injuries in general, fractions, ligaments of the body, etc.

[0080] Absorbent Pan or Pillow

[0081] The present SAPS can be used in absorbent pans, drip pans, and pillows, for absorbing liquids in general, or spills thereof, such as for use under machines or hydraulic hoses. Liquids may be coolants, solvents, water, and urine. They typically comprise 20-50 wt. % of SAP. A typical capacity may be a few litres per pan/pillow, up to about 100 litre. The pan or pillow may be provided with a resistant material, such as poly propylene.

[0082] Recipe for Forming Foamed Alginate/Montmorillonite

[0083] A 3 wt. % Na-Alginate solution was prepared and also a completely exfoliated 3 wt. % Na MMT suspension was prepared. These were mixed together in a 50:50 ratio to obtain a homogenous suspension. Following that a slow release (low solubility) Ca.sup.2+-based salt was mixed, for example a dicalcium silicate. In alternative approached CaCO.sub.3, Ca-citrate, and Ca-oxalate were used. The final concentration of the Na-Alginate:Na-MMT:Ca.sub.2SiO.sub.4 was 49:49:2. The system was found to gel internally via Ca cross linking and it formed a hydrogel nanocomposite, which was freeze dried with liquid nitrogen during 2 days at a temperature of about −200° C. at a pressure of about 10 Pa to obtain the present high porosity, lightweight foam structure.

TABLE-US-00001 Swelling performance Swelling g/g BASF Pamper Sodium Ca Luquasorb granules ALE alginate Density 0.7 0.271 0.0041 0.0035 Demi free 384 270 19.4 21.38 Saline free 50 46.6 19.3 16.0 AUL (1.0 Psi) >17 18.8 10.1 5.2

[0084] The density of the present SAPs (column 4 and 5) is much lower than that of comparable commercial SAPs. The swelling properties are somewhat lower, but for higher saline liquids are comparable.