CH716808B1 - Oil absorbent material. - Google Patents

Abstract

Impregnated nonwoven containing at least a) 1 to 50% by weight of oleophilic impregnation composition which contains at least one oleophilic substance and optionally at least one oil-gel-promoting component, and b) 50 to 99% by weight of thermoplastic nonwoven and impregnation compositions and processes for the production of such nonwovens.

Description

TECHNICAL AREA

The invention relates to a nonwoven material comprising an oleophilic and hydrophobic impregnation composition and a thermoplastic nonwoven.

STATE OF THE ART

Various materials are currently available to contain oil. Thermoplastic nonwovens are already used to absorb oil. According to the current state of the art, thermoplastic nonwovens often also have a high water absorption and are therefore not very efficient at extracting oil preferentially from water. Nonwovens according to the current state of the art are usually designed in such a way that they release the absorbed oil again through mechanical pressure (e.g. by squeezing), which can be a disadvantage in terms of trapping and retaining oil in the fabric structure over long periods of time.

It is known that nonwoven fabrics made of glass fibers treated with silicone compositions absorb oil. Nonwovens made of fiberglass cannot be easily disposed of when they contain absorbed oil and, therefore, often must be disposed of as toxic waste in a landfill. In addition, silicone treatments are known to have limited oleophilicity and sometimes even repel oil.

It is known that nonwovens made of cotton and other natural fibers such as wool absorb oil. This type of nonwoven is not very efficient because natural fibers are extremely hydrophilic compared to thermoplastic fibers.

EP-A-2 397 445 describes an impregnated nonwoven fabric containing at least one oleophilic impregnation composition and a thermoplastic nonwoven fabric. The nonwoven fabric described can be disposed of by conventional thermal processes (e.g. incineration) and resists water absorption and is at the same time able to absorb substances that are liquid and hydrophobic at ambient temperature, but soluble in organic solvents.

EP-A-2 397 445 indicates that the oleophilic substance is selected from silicone, wax, fluoropolymers or mixtures thereof and preferably has a melting point in a range from 50 to 170 ° C, most preferably a melting point in a range from 90 to 120 ° C. If the melting point is lower, the oleophilic substance can become liquid in hot weather and the nonwoven fabric according to the invention can lose its effectiveness. If the melting point is higher, the oleophilic substance may be too brittle to be effectively applied to the fibers of the nonwoven fabric.

SUMMARY OF THE INVENTION

One challenge for oil absorbent nonwovens is to achieve significant oil absorbency while minimizing water absorbency. This is particularly relevant for situations where the nonwoven material may first come into contact with water and then need to absorb oil from a water environment.

The invention describes treatment compositions which are applied to nonwovens in order to e.g. B. to enable improved oil absorbency and at the same time maintain a reduced water absorbency. A treatment composition is described which contains oleophilic components together with ingredients which aid the physical interaction between oil and the oleophilic components. The invention includes the inclusion of additional components that aid in the formation and stabilization of oil gels in order to further improve the preferential uptake and retention of oil substances which come into contact with the nonwoven material. One focus is on the addition of components that are miscible with oil substances and consequently contribute to the formation of gels with increased mechanical stability and retention on the nonwoven substrate. Such substances include emulsions made from natural oils (e.g. sunflower oil, rapeseed oil, canola, etc.), synthetic polymers and rubbers (e.g. latex) and natural polymer components and derivatives (e.g. based on polysaccharides, lignins, cellulose fibers). In addition to the oil and polymer components, fibrous structures such as short polymer fibers (as described in EP 2 748 359) and also short staple fibers from waste streams from agriculture and textile processing (e.g. silk, cotton, wool) can be included in the treatment composition in order to produce oil gels which form within and / or on the surface of the treated nonwoven fabric, to make it further mechanically resistant. Additional complementary elements in the composition can include the addition of components to support oil breakdown (e.g. enzymes).

The impregnation composition comprises at least one oleophilic substance and optionally an oil-gel-promoting component (an emulsifier), preferably at least 95% by weight of a mixture of the oleophilic substance and the optionally present oil-gel-promoting component (emulsifier ).

The weight ratio of oleophilic substance to an oil-gel-promoting component (emulsifier) is preferably in a range between 300: 1 to 450,000: 1, preferably between 2,000: 1 to 10,000: 1. If too much of an oil-gel-promoting component (emulsifier) is present in the oleophilic composition, the composition can become too thick or viscous and clog the pores of the nonwoven fabric. If the oleophilic composition contains too little of an oil-gel-promoting component (emulsifier), the fibers of the nonwoven fabric may possibly not be coated well enough with the composition. It could be shown that the composition has an accelerated uptake rate of hydrophobic substances such as oil and a much better absorption capacity compared to solutions according to the prior art within the claimed range. Surprisingly, the hydrophobicity and oleophilicity did not decrease as quickly as in the case of the solutions according to the prior art.

Preferably, the oleophilic substance is selected from silicone, wax, fluoropolymers or mixtures thereof and preferably has a melting point in a range from 40 to 150 or 50 to 170 ° C, most preferably a melting point in a range from 50 to 90 or 90 to 120 ° C. If the melting point is lower, the oleophilic substance can become liquid in hot weather and the nonwoven fabric according to the invention can lose its effectiveness. If the melting point is higher, the oleophilic substance may be too brittle to be effectively applied to the fibers of the nonwoven fabric.

The silicones can be selected from the group consisting of silicone elastomer, silicone elastomer / volatile silicone mixtures, silicone elastomer / non-volatile silicone mixtures, cyclomethicone, dimethicone, amodimethicone polymers, dimethicone copolyols and mixtures thereof.

The wax can be selected from the group consisting of candelilla wax, carnauba wax, Japan wax, esparto grass wax, cork wax, guaruma wax, rice oil wax, sugar cane wax, ouricury wax, montan wax, beeswax, shellac wax, whale rat (spermaceti), lanolin (wool wax) , Uropygial fat, ceresin, ozocerite (earth wax), petrolatum, paraffin waxes, polyolefin waxes, micro waxes; Montan ester waxes, sasol waxes, hydrogenated jojoba waxes, polyalkylene waxes, polyethylene glycol waxes and mixtures thereof.

The fluoropolymers can be selected from one or more of the following: Copolymers based on ethylene, TFE and / or CTFE, which is modified with hydrogenated monomers, or mixtures of these fluoropolymers with homopolymers of CTFE or (co) polymers on the Based on CTFE (PCTFE) containing at least 99 mol% CTFE, with the addition of 100 being one or more fluorinated monomers or hydrogenated monomers; the fluoropolymers and / or the corresponding mixtures optionally mixed with hydrogenated plasticizers.

The oil-gel-promoting component (emulsifier) is preferably selected from thickeners, polysaccharides, surfactants, emulsifier wax, cetearyl alcohol, polysorbate 20, ceteareth 20 or mixtures thereof.

The surfactant can be selected from the group consisting of alkyl monoglycosides, alkyl polyglycosides, sucrose alkyl esters, tertiary or quaternary alkylamine alkoxylates, non-alkoxylated tertiary or quaternary alkylamines, alkylamine oxides, alkyl betaines or mixtures thereof.

Non-woven materials / non-woven materials

The average fiber diameter is preferably in a range from 0.5 to 18 mm.

The weight per unit area of the impregnated nonwoven fabric is preferably in a range from 10 to 2000 g / m2, most preferably from 500 to 1900 g / m2.

The nonwoven fabric is preferably not coated with a seal and does not have an air-impermeable layer. In contrast to some of the solutions proposed in the prior art, it has been found that an air-permeable, impregnated fleece is much better able to absorb liquid hydrophobic substances.

The air permeability (measured in accordance with DIN 53887) is preferably in a range from 200 to 1500 l / m2 at a pressure of 2 mbar.

The thermoplastic nonwoven is preferably made from staple fibers, preferably from staple fibers with a staple length in the range from 5 to 150 mm, preferably 30 to 100 mm.

The thermoplastic nonwoven is preferably carded, wet-laid, spunbond, melt-blown or air-laid.

The textile is preferably needled, spun, thermally bonded, calendered, chemically bonded, sewn, woven, crimped, knitted, knitted, knitted and combinations thereof.

The thickness of the impregnated nonwoven fabric is preferably in a range from 1 to 20 mm, most preferably in a range from 2 to 8 mm.

The width of the impregnated nonwoven fabric is preferably in a range from 2 to 20 m, preferably from 5 to 12 m.

The length of the impregnated nonwoven fabric is preferably in a range from 10 to 300 m, preferably from 90 to 130 m.

Preferably, the thermoplastic nonwoven is selected from all synthetic fibers or fibers on a natural basis, most preferably from polyethylene nonwoven, polyester nonwoven, polypropylene nonwoven or mixtures thereof.

The linear mass density of the fibers of the nonwoven fabric is preferably in a range between 10 and 50 decitex, most preferably 15 to 35 decitex. Typical nonwovens have fibers with a linear density of about 0.5 to 6 decitex. It has surprisingly been found that a much higher linear mass density of the fibers results in an impregnated nonwoven fabric with much better adhesion of the impregnating composition to the fibers compared to typical linear mass densities. The resulting impregnated fleece with the higher linear mass density was also significantly more stable.

The average fiber diameter is preferably in a range from 0.5 to 18 μm.

The weight per unit area of the impregnated nonwoven is preferably in a range from 10 to 2000 g / m 2, most preferably from 500 to 1900 g / m 2.

The nonwoven fabric is preferably not coated with a seal and does not have an air-impermeable layer. In contrast to some of the solutions proposed in the prior art, it has been found that an air-permeable, impregnated fleece is much better able to absorb liquid hydrophobic substances.

The air permeability (measured in accordance with DIN 53887) is preferably in a range from 200 to 1500 l / m2 at a pressure of 2 mbar.

The thermoplastic nonwoven is preferably made from staple fibers, preferably from staple fibers with a staple length in the range from 5 to 150 mm, preferably 30 to 100 mm.

Preferably, the thermoplastic nonwoven is carded, wet-laid, spunbond, melt-blown, or air-laid.

The textile is preferably needled, spun, thermally bonded, calendered, chemically bonded, sewn, woven, crimped, knitted, knitted, knitted and combinations thereof.

The thickness of the impregnated nonwoven fabric is preferably in a range from 1 to 20 mm, most preferably in a range from 2 to 8 mm.

The width of the impregnated nonwoven is preferably in a range from 2 to 20 m, preferably from 5 to 12 m.

The length of the impregnated nonwoven fabric is preferably in a range from 10 to 300 m, preferably from 90 to 130 m.

Treatment of nonwovens

The treatment agent is applied to the nonwoven material according to an established textile process in which an aqueous mixture of the treatment is brought into contact with the nonwoven substrate (e.g. by upholstering, coating, spraying, foaming, etc.), followed by drying and optionally curing at elevated temperature (eg> 150 ° C) when crosslinking components are also contained in the applied treatment mixture.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below with reference to the drawings, which serve to illustrate the presently preferred embodiments of the invention and not to limit them. In the drawings, FIG. 1 shows a graphic representation of the results summarized in Table 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Characterization of the absorption effectiveness: The following procedure was used to determine the oil uptake on water-saturated nonwovens. 1. Cut 5 cm x 5 cm pieces from the test fabric. 2. Weigh the dry tissue test pieces (accuracy of the balance: 10 mg). 3. In a glass beaker, immerse the tissue horizontally in water (ambient temperature) and leave it fully immersed for 5 minutes. The method can optionally be carried out with sea water. 4. Remove the tissue from the water and allow the water to drip from the tissue for 1 minute while holding it vertically by one edge while the bottom edge of the tissue touches the glass beaker to prevent drops from forming on the edge of the tissue to prevent. 5. Weigh the wet fabric. The difference between dry and wet weight is the absolute water absorption. The relative water uptake is calculated by dividing the absolute water uptake volume by the initial dry weight of the tissue piece. 6. Immerse the wet (saturated with water) tissue at ambient temperature horizontally under the surface of the target oil substance (e.g. crude oil) and leave it immersed for one minute at room temperature. 7. Remove the piece of tissue from the oil and allow the oil to drain from the edge of the tissue for one minute while the tissue remains in contact with the edge of the glass dish while the oil flows out of the tissue (as in point 4). 8. Weigh the fabric again. 9. Centrifuge the mixture of oil and water from the glass dish. Water and oil separate completely in a laboratory centrifuge in a few minutes. 10. Measure the amount of water e.g. by marking the boundary between water and oil, remove the liquids completely, take the weight and fill them with water up to the mark and weigh them again. 11. The oil uptake is the weight difference from the wet tissue to the tissue with water and oil plus the mass of the water from the phase separation. The final mass of the water uptake is the water uptake calculated in point 5 minus the mass of the water from the phase separation.

Calculations: where mdry: weight of the dry tissue (point 2) mwet: weight of the wet tissue (point 4) mÖl: weight of the tissue after immersion in oil (point 7) mWasserinÖlbad: weight of the water in the oil bath (point 10 )

example 1

A prototype of a treatment composition (OG1301) was prepared on the basis of an aqueous emulsion of hydrophobic aliphatic polyurethanes and paraffin wax (60-62 ° C melting range). The preparation was diluted with water in various proportions and applied to a needle-punched polyester fleece (600 g / m2) with a lab padder and then dried in a laboratory tensioning machine (120 ° C. for 10 minutes). The resulting nonwoven samples were cut into 5 cm x 5 cm pieces and characterized for water and oil absorption using the method described above.

The test data of the samples (Table 1) indicate that the untreated fleece absorbs large amounts of water and small amounts of oil. In contrast, the nonwovens treated with the prototype of the OG1301 treatment achieve high oil absorption and minimal water absorption, which match the properties of a material capable of absorbing oil from aquatic environments such as lakes, rivers and oceans.

Table 1. Water and oil absorption test for polyester non-woven fabric treated with prototype oleophilic and hydrophobic treatment (OG1301). 1 OG1301 15% 34 25 489 42 522 14.5 2 OG1301 10% 43 21 501 11 545 11.6 3 OG1301 8% 94 41 456 58 550 4.8 4 OG1301 6% 79 0 480 10 559 6.1 5 OG1301 4% 101 16 469 12 570 4.7 6 OG1301 3% 89 6 451 10 539 5.1 7 OG1301 2% 159 52 409 40 567 2.6 8 Untreated reference 574 21 97 3 672 0.2

Example 2

A number of treatment compositions were prepared on the basis of an aqueous mixture of copolymer wax (Clariant Ceridust 8020TP) as the oleophilic wax component and styrene-butadiene copolymer latex (Synthomer Litex S 83) as the oil-gel-promoting component. Aqueous formulations were prepared by adding isopropyl alcohol, butyl diglycol and stabilizer (BYK Disperbyk-110) and mixing the ingredients in a glass beaker. The proportion of wax and latex components was varied according to the compositions described in the table below:

Table 2. Prototype formulations of aqueous mixtures.

OG1313 17.0% 16.9% 0.5% 5.3% 0.5% 59.9% 100.0% OG1323 20.1% 12.9% 0.5% 5.4% 0.5% 60.7% 100.0% OG1333 23.3% 8.7% 0.5% 5.4% 0.5% 61.6% 100.0% OG1343 26.6 % 4.4% 0.5% 5.5% 0.5% 62.5% 100.0%

The preparations were diluted 1: 1 with water and then applied with a laboratory padding to two different needled polyester nonwovens (350 g / m2 and 500 g / m2) and then dried in a laboratory tensioning machine (120 ° C for 10 minutes). The resulting nonwoven samples were cut into 5 cm x 5 cm pieces and characterized for water and oil absorption using the method described above.

The test data for the samples (Table 3) show that the nonwovens treated with the wax and latex treatment base achieve high oil absorption and low water absorption.

Table 3. Water and oil absorption tests for two different weight polyester nonwovens treated with prototype treatment formulations. 1 OG1313 350 81 21 217 10 298 2.7 2 OG1323 350 78 22 282 5 360 3.6 3 OG1333 350 71 25 254 49 325 3.6 4 OG1343 350 62 7 261 19 323 4.2 5 OG1313 500 57 18 378 42 434 6.7 6 OG1323 500 137 21 231 15 368 1.7

Example 3

The treatment compositions were prepared on the basis of an aqueous mixture of montan wax (Clariant Ceridust 5551) and a 6% strength chitosan solution. Aqueous formulations were prepared with further addition of isopropyl alcohol and mixing the ingredients in a glass beaker. Aqueous mixtures were produced in amounts between 10 to 30% by weight of the montan wax component and 5 to 15% of the chitosan solution. The preparations were then applied to a needle-punched polyester non-woven fabric (500 g / m2) with a laboratory padding and then dried in a laboratory tensioning machine (120 ° C. for 10 minutes). It was observed that the treatment formulations caused a homogeneous impregnation of the nonwoven fabric. The absorption properties of the nonwoven fabric samples were observed by immersion in water and crude oil. In comparison with an untreated nonwoven, the treated nonwoven resulted in a visibly higher absorption of oil and a lower absorption of water.

Example 4

The treatment compositions were prepared on the basis of an aqueous mixture of copolymer wax (Clariant Ceridust 8020TP), a 20% strength emulsion of coconut oil and a 5% strength dispersion of silk microfibers. Aqueous formulations were prepared with further addition of isopropyl alcohol and mixing the ingredients in a glass beaker. Aqueous mixtures were prepared in amounts between 10 and 30% by weight of the copolymer wax component, 5 and 10% of the coconut oil emulsion and 5 and 20% of the silk fiber dispersion. The preparations were then applied to a needle-punched polyester non-woven fabric (500 g / m2) with a laboratory padding and then dried in a laboratory tensioning machine (120 ° C for 10 minutes). It was observed that the treatment formulations caused a homogeneous impregnation of the nonwoven fabric. The absorption properties of the nonwoven fabric samples were observed by immersion in water and crude oil. In comparison with an untreated nonwoven, the treated nonwoven resulted in a visibly higher absorption of oil and a lower absorption of water.

Claims (13)

1. Impregnated nonwoven containing at least a) 1 to 50 wt .-% oleophilic impregnation composition which contains at least one oleophilic substance and optionally at least one oil-gel-promoting component, and b) 50 to 99% by weight of thermoplastic nonwoven fabric. 2. Impregnated nonwoven fabric according to claim 1, characterized in that the impregnation composition contains the at least one oleophilic substance and the at least one oil-gel-promoting component, preferably at least 95% by weight of a mixture of the oleophilic substance and the oil-gel-promoting Component, contains. 3. Impregnated nonwoven fabric according to claim 2, characterized in that the weight ratio of the oleophilic substance to the oil-gel-promoting component is in a range between 300: 1 to 450,000: 1, preferably between 2,000: 1 to 10,000: 1, lies. 4. Impregnated nonwoven fabric according to one of claims 2 or 3, wherein the oleophilic substance is selected from silicone, wax or mixtures thereof and preferably has a melting point in the range from 40 to 150 ° C, most preferably a melting point in the range from 50 to 90 ° C has. 5. Impregnated nonwoven fabric according to one of claims 2 to 4, wherein the oil-gel-promoting component is selected from at least one of oil-soluble polymers, preferably polyurethane, latex; natural oils, preferably sunflower oil, rapeseed oil; naturally occurring polymers and derivatives, preferably polysaccharides, lignins, cellulose fibers; short fiber materials, preferably silk, chitosan, cotton, wool; or mixtures thereof. 6. Impregnated nonwoven fabric according to one of claims 1 to 5, wherein the thermoplastic nonwoven fabric is selected from all synthetic fibers or fibers on a natural basis, most preferably selected from polyethylene nonwoven fabric, polyester nonwoven fabric, polypropylene nonwoven fabric or mixtures thereof. 7. Impregnated nonwoven fabric according to one of claims 1 to 6, wherein the linear mass density of the fibers of the nonwoven fabric is in a range between 10 and 50 decitex, preferably 15 to 35 decitex. 8. Impregnated nonwoven fabric according to one of claims 1 to 7, wherein the weight per unit area of the impregnated nonwoven fabric is in a range from 10 to 2000 g / m 2, preferably 500 to 1900 g / m 2. 9. Impregnated nonwoven fabric according to one of claims 1 to 8, wherein the nonwoven fabric is not coated with a sealing agent and does not have an air-impermeable layer, so that the impregnated nonwoven is much better able to absorb fussing hydrophobic substances. 10. Impregnated nonwoven fabric according to one of claims 1 to 9, wherein the thermoplastic nonwoven fabric is made from staple fibers, preferably from staple fibers with a staple length in a range from 5 to 150 mm. 11. Use of the impregnated nonwoven fabric according to one of claims 1 to 10 for the absorption of substances which are liquid and hydrophobic at ambient temperature, but soluble in organic solvents. 12. Impregnation composition for the production of an impregnated nonwoven fabric according to one of claims 1 to 10 in the form of an oleophilic impregnation composition which contains at least one oleophilic substance and optionally at least one oil-gel-promoting component, preferably as an aqueous solution, dispersion or suspension. 13. A method for producing an impregnated nonwoven fabric according to any one of the preceding claims 1-10, wherein a thermoplastic nonwoven fabric is impregnated with 1 to 50 wt .-% of an oleophilic impregnation composition, the at least one oleophilic substance and optionally at least one oil-gel promoting component , based on 50 to 99 wt .-% of the nonwoven fabric contains.