EP0672772A2 - Biologically degradable nonwoven and composite nonwoven materials - Google Patents

Abstract

Fibre fleece comprises at least one sort of thermoplastic fibre, which comprises natural polymers, natural polymers which are modified with synthetic polymers and/or synthetic polymers. The fibres are also proportionately modified with starch (which is not obtained by fermentation).

Description

From the published documents DE 40 14 176 A1 and DE 4242538 A1, biodegradable molding compositions or fiber mats are known, which mainly consist of renewable raw materials and often stick together under pressure and heat by activating the lignins or pectins in the tool and upon exposure to a biological one Environment can rot. However, time is an important factor for this product technology, especially since the problem with renewable raw materials in technical use is primarily the often non-existent thermoplastic properties of these materials.

It was now the object of the invention for the nonwoven area, predominantly where grade purity and therefore recycling is hardly possible, to find a largely configurable decomposable thermoplastic polymer fiber, which, processed into the nonwoven, molded part, but also, for example, as a nonwoven film composite, through the connection of plastic - and natural properties allow rapid technical treatment steps for e.g. vacuum or compression molding, but also HF, ultrasound, thermowelding and the like, for uses in geospatial areas, but also in combination and additional use of renewable raw materials such as jute, flax, sisal, wool etc. , or mixtures thereof, and also in combination with other degradable organic additives, for example foamed starch. In spite of these requirements, these nonwovens or composite materials, which are often permeable to air, should be completely or partially decomposable, water-soluble, or in a preferred version also compostable under the influence of a natural environment, and in the latter case should not endanger the microorganisms through toxic components or degradation products.

The possible applications of these nonwovens or composites are about designing them so that they can be used for almost the entire area of geotextiles, e.g. in the consolidation of embankments, in tunnel or waterway construction, for filtration, in the thermal and acoustic insulation area, as well as in gardening needs, e.g. for composting plants and plant pots, for packaging e.g. Apples, and in agriculture as e.g. cover mats that can be plowed under, or carved e.g. as soil loosening and improvement, such as when used in hygiene and medicine, z. B. are suitable as diapers and plasters.

Since such, because of different filling quantities and / or modifications based on starch, based on controlled degradability, thermoplastic polymer fibers that cannot be constructed are offered by the textile market, film manufacturers with films that e.g. B. are extrudable from starch, or which are easier to fill with starch, or are multi-layered, e.g. with PE / PP or PET / PE layers (and thus come close to the properties of bicomponent fibers) and can then be fibrillated, make the appropriate film fibers available for the time being. Here these carriers, e.g. also filled with more than 15% starch, as in the case of composite materials with appropriately modified foils, to solve composting, since this would relieve comparatively inexpensive composting, landfills and incineration plants.

These different tasks are then also, predominantly by different starch proportions and / or starch modifications, e.g. amylose, which are not obtained by fermentation for reasons of cost in the synthetic polymer film fibers and / or copolymer fibers used or with natural or modified natural polymer film fibers and / or biomodified polymer staple fibers, type A , achieved by different arrangement and combinations of fibers within the nonwovens, or for example by layered structure, or also combined with other decomposable materials, but also by A wide variety of mixing ratios for the fibers used, which allow, for example, a customizable initial strength tailored to the application or, for example, rapid deformability to the molded part. As compostable and degradable, as a supplement to the fiber materials used from or with starch according to claim 1, type A, products from the following areas are particularly suitable as matrix products B, provided that they come from renewable raw materials or, for example, from natural or synthetic polymers made from cellulose Sugar, for example, polyhydroxy fatty acids (PHB / PHBV), from protein, for example gelatin (polypeptides), from polycaprolactone, from polylactides and the like, and, if water-soluble products are in particular demand, are made from, for example, aligates, polyvinyl alcohol or unsaturated carboxylic acids. For the photo degradation of fibers or fiber film combinations, which are also possible, are particularly suitable as matrix products B, for example for covers in the agricultural sector, materials based on ethylene / carbon monoxide and ethylene and styrene with vinyl ketones or olefins with additives which react specifically to UV exposure. For example, foams, chips or any other conceivable formats made of the materials mentioned are conceivable as additives.

In addition to products based on starch, as well as natural or naturally modified polymers made of polyester, which can be obtained predominantly from starch, by fermentation, or by plants modified by means of bacterial strains, such as potatoes or rapeseed, and are often already water-soluble, they are in the preferred embodiment to achieve maximum advantages through the desired solutions thermoplastic decomposable fibers, which are produced from an olefin film predominantly by fibrillation, since these inexpensive polyolefin films have high additions of also inexpensive biological starch or modified starch of more than 50% from corn, potatoes and the like can be added, which is quantitatively only possible in significantly smaller amounts with spun synthetic polymer fibers, and which then also leads to much longer rotting times with such fibers spun with starch components.

For some time now, packaging films made of starch or those with starch bio-modified polyolefins have been offered for the packaging sector. For the inventive tasks and the applications on the non-woven market, it is therefore necessary to fibrillate these films, in some cases also to cut them to length, in order to make them usable in order to produce the required processable fibers. These bio-modified thermoplastic film fibers should mainly be those which have selected proportions, starch and, if necessary, further additives of e.g. Vegetable plasticizers, unsaturated biological oils, fats or additives for the formation of peroxides, predominantly as prooxidants, which lead to a reduction in the mechanical properties of the polymers by increasing the surface area through improved heat and oxygen supply, the oxidative chain degradation then taking place to a degree , which then by degrading the molar mass (<1000 for e.g. composting), when a bacterial environment occurs, thus only on the landfill, in the ground, in the regulated composting area, through the type and proportions of the starch and aggregates used, largely for the duration of the degradation can be constructed, disintegrate as planned, or are water-soluble.

In this way, this material, for example when using at least one further biological matrix fiber, such as jute, coconut, flax and the like, or an exclusive use of this starch containing synthetic polymer, staple or film fibers, or natural or naturally modified, largely on starch-based polymer fibers to the mat, or in combination with other degradable polymer fibers, for example copolyesters (CPEE) and copolyamides, such as those from the University of Lodz, Poland; for the Techtex Symposium 1992, Frankfurt, Lecture 402, without damage to earth and water, thus groundwater problems in the soil area, in the landfill, as in compost, can be used by converting to biomass.

In the geographic area it can e.g. When consolidating tunnels or railroad embankments, it makes sense not only to spray flame retardants, but also to mix these materials with e.g. to combine inorganic materials such as glass fabrics and the like, or organic polymer fiber structures, in order to firstly use the biodegradable fibers to drain, separate, or e.g. also to form a planting layer, to have a medium-term strength component via the thermally fixable polymer fibers containing starch, but on the other hand also e.g. to get an additional stability and reinforcement layer against fire or earth pressure.

In the hygiene sector, it is important to find solutions, especially for diapers, to solve the enormous space or combustion requirements. Here are solutions in combination of fiber layers made of, if bio-modified, at least for a short time hydrophobic thermoplastic fibers, and those with high storage capacity from e.g. Viscose, or also bio-modified thermoplastics through additional so-called superabsorbers, e.g. Polyacrylate cores with and without fiber components, and conceivable in connection with another layer of a biodegradable film.

Furthermore, the use of these materials was also to be aimed for deformed parts, such as plant pots or food packaging or filters, where, for example, the separating properties of different liquids with superabsorbent components can also be used, and where rapid working cycles, e.g. in the pressing process, due to the thermoplastic binding fibers be made possible.

example 1

These fiber mats for molded parts for the packaging sector (apples) are made from a mixture of 30% fiber A with at least 20% starch in order to also use e.g. keep compostable with the food content, and needled 70% jute fiber 400 - 500 g m², then predominantly placed in one or more work steps between hot plates, or partially Exposed to radiant heat, preheated thermally, and then placed and deformed in a cooled tool. After a short pressing time, they can be sufficiently solidified, taken out, punched, and used again.

Example 2

For embankment consolidation, 20% a type A film fiber with more than 50% starch, 60% flax and 20% superabsorbent are conceivable, needled and thermofixed, whereby the superabsorbent has the task of binding nutrient liquid for a plant seed and through the permanent Moisture absorption and dispensing ability for rapid rooting eg to care for sown grasses.

Example 3

In the area of coverable mats, it is also primarily a question of using air and moisture-permeable and heat-insulating non-woven products instead of films with a mixture of 20%, an LDPE film fiber type A filled with at least 20% starch and 80% of a film fiber B, made from ethylene / carbon monoxides, thermally bonded, the majority of the matrix fibers in particular being photo-degradable by the action of light, especially UV, and thus being able to be picked up easily after use.

Example 4

For the area of diaper pants, the upper dry-holding fiber and sweat layer, for example spun polyethylene fibers modified with starch or also spun polyester fibers (CPEE), which are at least initially hydrophobic, are conceivable, or mixtures of PP and PE fibers, predominantly thermally bonded. As an absorber layer for absorbing liquid e.g. Viscose with or without superabsorbent components can be used, but also e.g. modified PP or PE fibers bound with superabsorbers, thermally or with degradable acrylic dispersions, and as a final seal and for welding, a bio-modified polyethylene film made of LDPE.

Claims (11)

Nonwoven fabric consisting of at least one type of thermoplastic fiber A, consisting essentially of natural polymers and / or of natural polymers modified with synthetic polymers, and / or synthetic polymers, characterized in that the fibers A used here are additionally obtained in part with those not obtained via fermentation biological starch are modified. Nonwoven fabric according to claim 1, characterized in that the fiber types A are essentially those made of polyolefins and / or polyester / copolyesters. Nonwoven fabric according to claim 1, characterized in that the biodegradability of the nonwoven fabric is controlled with thermoplastic fibers of the fiber type A, predominantly by the proportionate additions and / or modifications of biological starch from beet, sugar cane, corn, wheat and the like. Nonwoven fabric according to one of the preceding claims, characterized in that these special fibers A in particular from a film, e.g. Fibrillating. Non-woven fabric according to claim 1, characterized in that the non-woven fabric is mixed with at least one further fiber type B, which consists of biodegradable polymer fibers and / or natural fibers such as wool, jute and the like. Nonwoven fabric according to one of the preceding claims, characterized in that the nonwoven is mechanically consolidated, e.g. by needles or thermally or via binders or from combinations of all of these possibilities. Nonwoven fabric produced according to one of the preceding claims, characterized in that the nonwoven fabric consists of at least two differently composed fiber layers. Nonwoven fabric produced according to one of the preceding claims, characterized in that this nonwoven fabric consists of at least two, predominantly separately produced layers of nonwoven fabrics according to previous claims, these nonwovens being connected to one another by different possibilities corresponding to the prior art. Non-woven fabric according to one of the preceding claims, characterized in that within the non-woven fabric and / or on one or both sides on the surfaces and / or between the layers, over the entire surface or partially, at least one functional and / or stabilizing layer and / or additives and / or or reinforcing material consists of also rot-resistant material, such as fibers, foils, grid fabrics, scrims, meshes, sprayed substances or the like. Nonwoven fabric produced according to one of the preceding claims, characterized in that within the nonwoven fabric and / or, on one or both sides on the surfaces and / or between the layers, over the entire surface or partially, at least one functional and / or stabilizing layer or reinforcing material in the form of Fibers, fleeces, foils, Ge weave, meshes, sprayed substances or the like, consists of non-rotten materials. Use of a nonwoven fabric according to one or more of claims 1-10.