Composite, method for producing a product from a composite, and method for producing a shaped body from a composite

Abstract

The invention relates to a composite for producing shaped bodies, which comprises at least one binding agent, at least one filler and at least one reinforcing agent. The invention is characterized in that the at least one filler and the at least one reinforcing agent are comminuted bast fiber plants and/or whole bast fiber plants. The invention also relates to a method for producing a product, especially a granulate, from a composite, which involves the following method steps: coating an extruder with at least on binding agent and bast fiber plants and/or comminuted bast fiber plants; melting at least one binding agent; extruding the material; granulating the extruded material, and; solidifying the material after cooling. The invention additionally relates to a method for producing a shaped body from a composite, which involves the following method steps: feeding a granulate made of the composite into an injection molding machine; melting the granulate; injecting the molten material, especially under pressure, and; solidifying the composite in the mold by cooling. The invention relates to another method for producing a shaped body from a composite, which is characterized by the following steps: feeding a mixture consisting of at least one binding agent and of bast fiber plants and/or of comminuted bast fiber plants, especially in their natural composition, into an extruding machine or into a strand depositing device, and; extruding or strand-depositing the mixture, whereby the mixture is at least partially melted.

Description

[0001] The invention relates to a composite for producing shaped bodies, said composite comprising at least one binding agent, at least one filler and at least one reinforcing agent. The invention furthermore relates to a method for producing a product from a composite, as well as a method for producing a shaped body from a corresponding composite.

[0002] Raw-material suppliers frequently conduct costly and time-intensive research and development to meet the increasing demands for technologically high quality shaped parts of thermoplastic molding masses. The development is aimed at obtaining ever more complicated molecular structures, for example to achieve even higher form stability under heat or even better cold impact resistance of the materials or to further improve the durability. A large share of the research and development money is furthermore used to develop synthetically produced glass, coal or aramide fibers with a so-called sizing material, meaning a bonding agent between the reinforcing fiber and the polymer matrix. This is designed to obtain plastic composites or composite materials with increased strength. The aforementioned developments are becoming more and more detailed and complex, thus making the plastic materials more and more expensive.

[0003] At present, plastic materials for high-quality applications are either polymerized in a synthetically involved technique or up to 40% glass, coal or aramide fibers are mixed into a low-quality polymer matrix as reinforcement. A high amount of energy is required to produce such fibers. In addition, already macerated natural fibers such as flax or sisal are presently worked into synthetic material matrices to create a substitute for glass fibers. However, no replacement has been found so far for glass fibers with respect to strength.

[0004] Starting with this state of the technology, it is the object of the present invention to provide a composite for producing a product made from this composite, to provide a method for producing shaped bodies as well as to provide corresponding techniques for producing these shaped bodies at low cost and using the lowest possible amount of synthetic products on the basis of crude oil. In particular, it is the object of this invention to contribute to a reduction in CO2 emissions.

[0005] It is furthermore an object of the present invention to make available a technologically high-quality composite for producing shaped bodies. Furthermore, it should be possible to produce these shaped bodies without expensive synthetic fiber production techniques, as well as at cheaply and with a low amount of energy.

[0006] This object is solved with a composite for producing shaped bodies, which contains at least one binding agent, at least one filler, and at least one reinforcing agent. The composite is modified in that the at least one filler and the at least one reinforcing agent are comminuted bast fiber plants and/or whole bast fiber plants.

[0007] As a result of this modification according to the invention of standard composite materials, it is possible to obtain technologically high-quality composites since bast fiber plants have an extremely high tensile strength and thus are particularly easy to use in technologically high-quality composite polymers. In addition, it is possible to produce corresponding composites or composite materials in this way, which are based to a large extent or completely on renewable crude materials, thus making them CO2 neutral. Owing to the fact that no polymerization technology is required and the expensive and involved synthetic fiber production is omitted, composite materials of this type and shaped bodies produced from these materials can be produced at considerably lower cost and require noticeably lower energy amounts for the production.

[0008] Within the framework of this invention, the term “composite” in particular also comprises the term “composite material.”

[0009] Particularly preferred as filler and reinforcing agent are comminuted bast fiber plants, which for the most part are not macerated but only cut up. A preferred composite in particular is modified in that the bast fiber plants and/or the comminuted bast fiber plants are essentially present in the natural composition of the plant components. Normally, the plant components (wood, fibers) are present as a unit, separated, macerated or still in part adhering to each other. When cutting up the bast fiber plants, a partial or complete separation between wood (shives1) and fibers can occur, which indeed can also have advantages. 1 Translator's Note: Shives normally refers to hemp, flax and wood byproducts.

[0010] The term shives in this connection refers to parts of the comminuted, lignified inside portion of the plant stem.

[0011] It is particularly preferred if the comminuted bast fiber plants comprise few shives that are separated and/or partially separated from the bast fibers. A natural composition of the plant components, in particular, is understood to mean that these still exist in the same quantitative composition as in nature.

[0012] The bast fiber plants and/or the comminuted bast fiber plants are preferably dried. The bast fiber plants and/or the comminuted bast fiber plants are furthermore preferably hemp, flax, kenaf, stinging nettle and/or toad flax. The dried and comminuted and/or cut bast fiber plants, preferably used as filler and reinforcing agents, have a considerably higher tensile strength than other natural fibers in the natural composition of the plant components and are thus predestined for use in technologically high-quality composite polymers. The fiber portion in this case functions as reinforcing agent and the shive portion essentially as the filler. Using the plant components in their natural composition means that the relatively involved separating and subsequent feeding operations following the comminuting or at least partial breakup of the material can be omitted.

[0013] Technologically high-quality composite materials can be obtained if the binding agent preferably includes synthetic and/or native monomers and/or polymers. The term native within the framework of this invention in particular also means biogenic. A native and/or biogenic monomer is lactic acid, for example, a breakdown product of the fermentation process. Native and/or biogenic polymers, for example, include plant starches from the family of polysaccharides, as well as lignin or even keratin from the family of animal proteins. However, the biogenic and/or native polymers or monomers can also include other known materials. Synthetic polymers, for example, are polyethylene, polypropylene, polystyrene and other polymers. The polymers are preferably thermoplastic and function as plastic matrix. The synthetic polymers are preferably produced from petrochemical base materials.

[0014] Additives are preferably provided and include, for example, bonding agents between the at least one filler and the at least one reinforcing agent and the matrix and/or the binding agent. Particularly suitable are additives that reduce, in particular, the combustibility and breakdown ability of the bast fiber plants and/or the comminuted bast fiber plants and/or the composites. For the purpose of this invention, a binding agent in particular also refers to a matrix.

[0015] It is particularly preferable if the reinforcing agents and the fillers are essentially enclosed completely by the binding agents and are fixated at their location.

[0016] It is preferable if the at least one filler and the at least one reinforcing agent are essentially combined, in particular in the natural form, thus making it possible to realize an especially cost-effective composite.

[0017] In addition, the composite can be foamed up if it contains at least one expanding agent, e.g. for producing insulating materials. The effect of the expanding agent preferably is either chemical and/or physical. A preferred example of a chemically effective expanding agent is a foam-producing material or, for example, sodium bicarbonate (baking powder). A physically effective expanding agent, for example, is water or CO2.

[0018] The production of the respective composites and thus also the respective shaped bodies is particularly easy if the at least one filler and/or the at least one reinforcing agent preferably functions as carrier for at least one expanding agent and/or at least one foaming agent. Water that is already present in the plants and/or plant parts or is additionally added and causes a foaming of the matrix and/or the binding agent at processing temperatures above 100° C. is particularly suitable for this. Insulation materials can thus be produced easily and cheaply while using safe expanding agents. The moisture content of the plant parts can vary, for example between 3% and 40% for hemp. Following a normal drying process, the plant parts generally contain approximately 12% residual moisture.

[0019] The aforementioned plants and plant parts furthermore have the advantage of causing low wear on the respective production machines as compared to the use of synthetic fibers, thus extending the service life of compounding and production machines. In addition, the processing of natural fibers does not pose a health threat, in contrast to the processing of glass fibers, so that fewer protective measures are required.

[0020] The composite is preferably produced by means of extrusion, injection-molding and/or strand-depositing.

[0021] A method for producing a product, in particular a granulate, from an aforementioned composite preferably includes the following steps:

[0022] supplying an extruder with at least one binding agent and bast fiber plants and/or comminuted bast fiber plants;

[0023] melting down of at least one binding agent;

[0024] extruding of the material;

[0025] granulating of the extruded material; and

[0026] solidification of the composite material through cooling.

[0027] The granulating can also be realized after the complete solidification of the material by cutting the extruded product.

[0028] For producing shaped bodies from the granulated and extruded material, the material is processed further with the following steps:

[0029] feeding of the granulate into an injection-molding machine;

[0030] injecting the melted material into a mold, in particular under high pressure;

[0031] solidification through cooling of the composite inside the mold.

[0032] As a result of this preferred injection-molding process, it is easy to produce in particular shaped bodies from the aforementioned composites, wherein comminuted bast fiber plants in particular are used.

[0033] While the bast fiber plants or the comminuted bast fiber plants are added or following this process, they are preferably stirred and/or mixed into the melted binding agent. The bast fiber plants and/or the comminuted bast fiber plants are preferably added before the at least one binding agent is melted. It is preferable if the comminuted bast fiber plants are comminuted in such a way that pieces measuring up to 3 mm result.

[0034] The mixture consisting of at least one binding agent and the bast fiber plants and/or the comminuted bast fiber plants is preferably heated up, such that at least one expanding agent is triggered to expand. As a result of this preferred exemplary embodiment, the mixture and in particular the binding agent foams up. An insulating material, for example, can thus be produced easily with this measure. A particularly easy and cheap method of foaming up is provided if the temperature is preferably at 100° C. or higher and the expanding agent is water, which is present in the bast fiber plants or the comminuted bast fiber plants and/or in the filler and/or the reinforcing agent or which is added.

[0035] The bast fiber plants and/or the comminuted bast fiber plants are preferably dried before they are added and/or supplied to the binding agent. The bast fiber plants and/or the comminuted bast fiber plants are furthermore enriched with water and/or another expanding agent before being added to the binding agent. An expanding agent can additionally or alternatively be added to the binding agent before or after the comminuted bast fiber plants are added. As a result of this measure according to the invention, the foaming effect can be increased.

[0036] An additional method for producing a shaped body from a composite, of the type described in the above, preferably comprises the following steps:

[0037] supplying a mixture comprising at least one binding agent and bast fiber plants and/or comminuted bast fiber plants, in particular in their natural composition, to an extruder or a strand-depositing device; and

[0038] extruding or strand-depositing the mixture, wherein the mixture is at least partially melted down.

[0039] Large slabs or semi-finished products can, for example, be produced with this preferred method. Insulating materials and sound insulating and/or heat-insulating shaped bodies can be produced easily if the mixture preferably is heated up enough, so that at least one expanding agent is triggered to expand. The temperature preferably is at 100° C. or higher and the expanding agent preferably is water that is present in the bast fiber plants or the comminuted bast fiber plants or in the filler and/or the reinforcing agent, or which is added.

[0040] The bast fiber plants and/or the comminuted bast fiber plants are preferably dried prior to being mixed into the at least one binding agent. The bast fiber plants and/or the comminuted bast fiber plants are furthermore enriched with water and/or at least one additional expanding agent before being mixed into the binding agent. In addition to or alternatively, an expanding agent can be added to the binding agent before or after the addition of the comminuted bast fiber plants. The foaming effect can be increased as a result of this measure according to the invention. Thus, a higher foaming effect can be achieved with this preferred embodiment of the method.

[0041] A shaped body preferably consists at least in part of a composite of the type described in the above and/or is preferably produced according to one of the above-described methods. Long bast fiber plant sections have an advantage with shaped bodies in the form of slabs. Thermoplastics filled with bast fiber plants, for example in the form of slab goods or semi-finished products, can be used for producing windowsills or similar items. Shaped bodies of this type show hardly any swelling caused by the effects of water. Shaped bodies that can be produced include, for example, wall reinforcements, floor stabilizers and slope stabilizers, floor plates with raised areas having non-skid top surfaces and provided, for example, with an anchor at the bottom as well as posts, meadow fences or garden fences, planters, poles for growing plants, manhole and pipe covers, outer shells for waste baskets, feed troughs, leakage basins, dog houses, raised seats, log-type play houses, climbing towers, garden furniture, park benches and the like. In addition, corresponding shaped bodies are also suitable for use as viewing and noise protection walls.

[0042] It is particularly preferable if recycled materials are used for the binding agents. The correspondingly produced shaped bodies can be used in road construction and as structural components for securing the slope and embankment area. As previously indicated, they can function as insulating materials or as large-dimension injection-molded articles, for example surfboards, boogie boards or similar items.

[0043] A device disclosed in WO 00/14312, in particular, can be used for comminuting the fiber plants. However, the fiber plant material is not compressed or broken up with this method, but is only cut to the desired length. For this, the fiber plant material is transferred to a receiving chute, meaning a receiving chute of a tobacco cutter known in the tobacco-processing industry, and is conveyed to an orifice. There, it is cut into sections having a desired length with the aid of a cutting device, provided with rotating or linearly moving blades. Within the framework of said invention, the fiber components as well as the wood and shive components preferably are not further processed and separated.

[0044] Bast fiber plant sections measuring from 0.1 to 150 mm, in particular from 2 mm to 50 mm, are preferably provided. With the preferred injection-molding process, fiber sections of 2 mm are used, wherein the share of fibers used can reach up to 40%.

[0045] With a preferably realized strand-depositing method, a fiber share of up to 70% can be realized.

[0046] Preferred matrix materials and/or binding materials used are polyethylene with a high density (PE-HD), polypropylene homopolymer (PP), polystyrene (PS) and starch (MaterBi2, Y-type3). 2 Note: Also spelled materbi=biodegradable plastic material 3 Note: See high molecular weight glutenins

Claims

1. A composite for producing shaped bodies, comprising at least one binding agent, at least one filler and at least one reinforcing agent, characterized in that the at least one filler and the at least one reinforcing agent are comminuted bast fiber plants and/or whole bast fiber plants.

2. The composite according to claim 1, characterized in that the comminuted bast fiber plants and/or the whole bast fiber plants are present in the natural composition of the plant components.

3. The composite according to claim 1 and/or 2, characterized in that the bast fiber plants and/or the comminuted bast fiber plants are dried.

4. The composite according to one or several of the claims 1 to 3, characterized in that the bast fiber plants and/or the comminuted bast fiber plants are hemp, flax, jute, kenaf, stinging nettles and/or toad flax.

5. The composite according to one or several of the claims 1 to 4, characterized in that the binding agent comprises synthetic and/or native monomers and/or polymers.

6. The composite according to one or several of the claims 1 to 5, characterized in that the at least one filler and the at least one reinforcing agent, in particular in the natural form, are essentially combined.

7. The composite according to one or several of the claims 1 to 6, characterized in that the composite additionally contains at least one expanding agent.

8. The composite according to claim 7, characterized in that the effect of the expanding agent is chemical and/or physical.

9. The composite according to claim 7 and/or 8, characterized in that the at least one filler and/or the at least one reinforcing agent functions as carrier for at least one expanding agent.

10. The composite according to one or several of the claims 1 to 9, characterized in that the composite can be produced with the aid of extrusion, injection-molding and/or strand-depositing.

11. A method for producing a product, in particular a granulate, from a composite according to one or several of the claims 1 to 10, characterized by at least the following steps:

coating of an extruder with at least one binding agent and bast fiber plants and/or comminuted bast fiber plants;

melting of at least one binding agent;

extruding of the material;

granulating of the extruded material; and

solidification of the material through cooling.

12. The method according to claim 11, characterized in that the material can be granulated before as well as after the solidification of the composite.

13. A method for producing a shaped body from a composite according to one or several of the claims 1 to 10, characterized by at least the following steps:

feeding a granulate of the composite material into an injection-molding machine;

melting of the granulate;

injection-molding of the melted material, in particular under high pressure; and

solidification of the composite inside the mold through cooling.

14. The method according to claim 13, characterized in that the granulate is produced according to one or both of the claims 11 and 12.

15. The method according to one or both of the claims 11 or 12, characterized in that during the process of adding the bast fiber plants and/or the comminuted bast fiber plants or thereafter, these are stirred and/or mixed into the melted binding agent.

16. The method according to one or several of the claims 11, 12 and 15, characterized in that the bast fiber plants and/or the comminuted bast fiber plants are added prior to the melting of the at least one binding agent.

17. The method according to one or several of the claims 11, 12, 15 and 16, characterized in that the comminuted bast fiber plants are comminuted so as to result in sections measuring from 0.1 to 150 mm and in particular from 2 to 50 mm.

18. The method according to one or several of the claims 11, 12, 15 to 17, characterized in that the mixture consisting of the at least one binding agent and the bast fiber plants and/or the comminuted bast fiber plants is heated up, such that at least one expanding agent is triggered to expand.

19. The method according to claim 18, characterized in that the temperature is 100° C. or higher and that the expanding agent is water, which is present in the bast fiber plants and/or the comminuted bast fiber plants and/or in an additional filler and/or an additional reinforcing agent, or which is added.

20. The method according to one or several of the claims 11, 12, 15 to 19, characterized in that the bast fiber plants and/or the comminuted bast fiber plants are dried before being added to the binding agent.

21. The method according to one or several of the claims 11, 12, 15 to 20, characterized in that the bast fiber plants and/or the comminuted bast fiber plants are enriched with water and/or at least one other expanding agent prior to being added to the binding agent.

22. The method for producing a shaped body from a composite according to one or several of the claims 1 to 10, characterized by the following steps:

supplying a mixture, consisting of at least one binding agent and bast fiber plants and/or comminuted bast fiber plants, in particular in their natural composition, to an extruder or a strand-depositing device; and

extruding or strand-depositing the mixture, wherein the mixture is at least partially melted.

23. The method according to claim 22, characterized in that the mixture is heated up enough, so that at least one expanding agent is triggered to expand.

24. The method according to claim 23, characterized in that the temperature is 100° C. or higher and that the expanding agent is water, which is present in the bast fiber plants and/or the comminuted bast fiber plants and/or in an additional filler and/or an additional reinforcing agent, or which is added.

25. The method according to one or several of the claims 22 to 24, characterized in that the bast fiber plants and/or the comminuted bast fiber plants are dried before being mixed with the at least one binding agent.

26. The method according to one or several of the claims 22 to 25, characterized in that the bast fiber plants and/or the comminuted bast fiber plants are enriched with water and/or at least one additional expanding agent before being mixed with the binding agent.

27. The shaped body, at least partially consisting of a composite, according to one or several of the claims 1 to 10 and/or produced according to a method as defined in one or several of the claims 13 and/or 14 and/or according to one or several of the claims 15 to 27.