DE69913901T2 - Process for the production of objects from raw, vegetable material by pressing - Google Patents

Abstract

For the production of biodegradable, compostable and recycling products, the material is a cake of sunflower or rape seed with an oil content of ≤ 20% and a protein content of ≥ 15%. It is wetted to give a moisture content of 5-55%. The cake is shaped in a press, with a mold of the product design. The molded material is heat dried, to stabilize it. The moisture content of the material is 10-25%, for heat shaping by pressure of 15-25 MPa at a temp. of 130-200 degrees C. The sunflower or rape seed material is initially given a mechanical treatment to break it down into homogenized granules with a mean diameter of 0.1-1.0 mm. The oil in the material is extracted partially, to give an oil content of ≤ 10% after drainage by trituration. The processed material is passed as a paste through a twin-screw extruder with, upstream to downstream, a chopper (8), a scraper (9), and if required, a bleed (11,12) for the liquid phase, and at least a reverse pitch module (10) to impose an axial compression on the solid matter, and an outlet (14). The twin-screw extruder has water injection (6,7) to set the moisture content of the material. The cake of sunflower or rape seed can be augmented by vegetable fibers.

Description

The The invention relates to a method for producing articles the basis of vegetable primary mass. It is the object of the invention to manufacture articles such as Container, Packaging, signs or posters, especially for the area To allow construction or establishment the - under Exploitation of for their function suitable characteristics such as durability and stability - biological are degradable, compostable and recyclable. Under “biological degradable is to be understood that the object mentioned at least Mostly of natural Microorganisms will decompose if it meets the appropriate conditions exposed, without releasing products that are toxic to the ecosystem and in a period from a few weeks to a few months. There is an item under "compostable" to understand the, crushed, homogenized and with the organic Mass and / or soil mixed, a non-toxic for the plants, nährreiches Substrate results. There is an item under "recyclable" to understand its mass to form an object from it Area can be reused.

The Environmental regulations are becoming increasingly stringent, especially for disposable ones Products (especially packaging) and conditioning, and it is trying to make these products by giving them a biological degradable and / or compostable and / or recyclable character is awarded to avoid becoming a pollutant become or an elaborate Require elimination treatment. Synthetic plastic masses meet in the Generally the latter requirement, but its recycling is very expensive and requires prior sorting to get the to separate different types of material from each other today's way of life is difficult to reconcile.

To limit these drawbacks, numerous studies have suggested that articles be made using various vegetable materials such as wood fiber, sunflower peel, paper pulp and, in association with these masses, binders, texturing agents, synthetic or reactive chemical adhesives (US-5 593 625, US-5 663,221, Patent Abstracts of Japan, Vol. 098 N004; JP 09327684 ) to get objects with good adhesion. However, this approach does not entirely solve the problem of object destruction after use due to the presence of synthetic or other additives. In addition, the most common synthetic binders and adhesives have the flaw that they release toxic substances, either gradually over time (urea formol, phenol formol), during production or during recycling (isocyanates). In some cases, small common items can be made, but the durability properties achieved do not allow the production of large items or items that are subjected to high stress.

Further has been suggested in some publications, the synthetic Binder through natural binders to be replaced, in particular by gelatin (WO-96/14361). This method consists of mixing a vegetable batch (essentially fibrous) with the natural Binder to a paste, which is then heated to diffuse to ensure the binder in the mass and the product too to form. The main disadvantage of this technique is its cost, which essentially result from the costs of the primary masses from which Product extracts, finished products or semi-finished products are formed become. About that In addition, the mechanical performance of such a technology materials achieved so far mediocre (the mechanical resistance is comparable to that of cardboard).

Furthermore certain lignocellulose residues from oil extraction processes were thermo-pressed, to give them adherence and to confer some mechanical resistance, however this remains mediocre, especially the bending strength of the products obtained.

It is an object of the present invention, the disadvantages of the known Shut down procedures and provide a new procedure with which is a biodegradable, compostable and recyclable Item manufactured under remarkable economic conditions can be.

It is another object of the invention to manufacture an article who benefits from good flexural strength that with applications such as B. in construction, furnishings, packaging, conditioning, etc. is compatible.

To this end, the manufacturing method according to the invention is that (a) a sunflower or rapeseed cake with an oil content of less than 20% by weight and a protein content of more than 15% by weight is used, so that a Water content essentially between 5 and 55 wt .-%, (b) a molding process is carried out by pressing said cake in a mold that corresponds to that of the desired object, and (c) a heat treatment or a drying treatment is carried out to solidify the object in its shape.

Under “Sunflower or rapeseed cake " usually the fixed oil extraction residue of whole or peeled Sunflower or rapeseed understood, independently from the extractant (pressing, extraction with solvent, etc.), this oil extraction can be wholly or partially, but the oil weight content of the product reduced to below a threshold of generally about 20%; the cake may be the subject of a previous partial protein extraction his protein weight content remains above 15, however. (All weight percentages are expressed in percent based on the weight of the dry matter; the Water content is expressed based on the total mass).

It could be determined experimentally that on the basis of a Primary mass, which is formed by sunflower or rapeseed cake on one to fulfillment in the manner defined above, with a conventional one Molding or thermoforming processes Molding products can be made that excellent adhesive properties and remarkable durability own without any additives. Consequently is the inventive method very economical as it is based on a natural Rohprimärmasse accomplished that is available very richly, without the addition of finished or semi-finished, synthetic or natural Products. It’s completely surprising that with such vegetable sunflower or rapeseed residue, very heterogeneous and so far as a by-product of little value viewed (only for Animal feed used as a good with low energy value), below satisfactory conditions a molding or thermoforming process carried out can be used to make an item with a quality which is equivalent to that of thermoformed synthetic plastic objects is. This remarkable result is invented a posteriori explained by the composition of sunflower or rapeseed cake, which Contain fibers and proteins, the latter being such Nature and content have such that the fibers diffuse and bond that a malleable matrix is formed. The hydrating water of the cake used a solvating effect on these proteins, their chains interact with the fibers.

The inventive method can be implemented using thermoforming of the cake, at which this is essentially between when pressing a temperature 130 ° C and Subjected to 200 ° C becomes. In this case, the portion of hydration of the cake set to a value between 5% and 25. With this range of values can good heat transfer, adequate use of protein chains can be achieved without Excessive degassing that tends to localize the material break. The thermoforming is preferably carried out with a print essentially between 15 and 25 MPa. Such a thermoforming process let yourself perform faster as a cold forming (will later mentioned), and leads for better mechanical resistance.

Around adhesiveness and durability of thermoformed objects to improve still further and to carry out thermoforming too the sunflower or rapeseed cake is preferred previously a mechanical cutting and homogenization treatment to give it such a grain size distribution, that the equivalent with D50 particles average diameter is between 0.1 mm and 1 mm. Under “middle D50 diameter " to understand a diameter in which 50 wt .-% of the particles by a vibrating screen fits with a mesh size, which corresponds to the diameter mentioned. (All grain size measurements done on the dry matter).

Consequently can by thermoforming a sunflower or rapeseed cake are manufactured that can be used in construction, and essentially of vegetable fibers bound by proteins be formed with a bending strength essentially between 10 and 25 MPa.

According to one Another procedure is the cake, which was previously a mechanical one Is subjected to dicing and homogenization treatment in order to such a grain size distribution to confer that mean diameter equivalent to D50 particles is less than 1 mm, by adding water to a water content essentially hydrogenated between 25 and 50%, making a plastic one Paste is created, which is then dried by pressing is cold formed until solidification. The pressure of the molding can can advantageously be set between 1 and 5 MPa. A Such a procedure results in a paste that can be modeled very easily lets (the Modeling properties are equivalent to those of a modeling paste), and enables the manufacture of objects with extremely different Molds at a very low cost. The mechanical resistance of the items received is lower than that of thermoforming as mentioned above.

Besides, can one finds that the remaining oil of the cake is an unfavorable one Has an effect on the shape and the quality of the objects received, and it advantageously becomes an at least partially degreased Cake with an oil content less than 10% by weight. It may be an oil-free cake can be used in which the sunflower or rapeseed cake triturates were. (Under “Oil-free Cake "will be in the Generally understood a cake with an oil content of maximum 2%). Thus, the hydrophobic repulsive forces are limited or suppressed tend to counteract fiber / protein binding.

The Cake can in particular be cut and homogenized and possibly at least in part by passage through a twin screw device de-oiled be the, downstream seen-, shear means, squeeze means, means for removing the liquid phase, at least one reverse gear module to achieve axial compression of the solid components, and an outlet for the solid components, wherein said twin screw device further with water injection means is equipped to adjust the water content of the cake. Such a treatment refines the texture of the cake and allows that fibers and proteins are shaped under optimal conditions to be bound together. About that In addition, a complementary oiling of the cake become.

The Sunflower or rapeseed cake may be made with vegetable fibers be enriched by the production costs of the products received lower still further. This procedure enables added value for goods from low-quality vegetable fibers (straw, sunflower husks) and is used especially when using a cake who is all its original Contains proteins (without partial extraction) or if the desired object is not strong to be subjected to mechanical stresses.

The inventive method allows the production of extremely diverse items: flat objects such as signs, posters, documents, followers etc., hollow objects such as z. B. containers, Packaging etc.

The The following examples are intended to illustrate the process according to the invention.

in the 1st example is the cake after de-oiling by conventional Pressing a preparatory treatment in a twin screw device subjected; this twin screw device and the molding tools to perform of molding or thermoforming in the examples are in the accompanying Drawings schematized. It shows:

1 a symbolic longitudinal representation of the aforementioned twin screw device;

2 a cross section through a plane A;

3 . 4 and 5 Vertical cuts of molds used in Examples 1, 2 and 3, respectively.

The in the 1 and 2 Schematic twin-screw device is used to carry out the preparation of cakes from the 1st example; this device is obtained with modules available from the company "CLEXTRAL" (registered trademark) under the general reference "BC45". Each module includes a tubular enclosure with the two walls 1 and 2 so that the heat in the core of the enclosure, where the active mechanisms are located, can be controlled. Certain modules are of the type that have two identical intermeshing screws, others of the type that include shear mixers made of twin cam disks. The various modules are powered by an electric motor 3 , with which output shaft speeds of up to 700 rpm can be achieved, rotated synchronously. In the examples, the selected speed is 100 rpm.

• – eine Förder- und Kompressionszone Z₁, umfassend einen Kuchenzuführungsbunker 4, Direktgang-Zweischneckenmodule mit abnehmender Steigung wie bei 5, und einen Kanal 6 mit einer Pumpe 7 zum Einspritzen von Wasser,
• – eine Scherzone Z₂, die mindestens einen Zweinockenscheiben-Mischer wie bei 8 umfasst,
• – eine Quetsch- und Kompressionszone Z₃, die Quetschmodule, die von Direktgang-Zweischneckenmodulen wie bei 9 mit einer stromabwärts abnehmenden Steigung gebildet werden, mit einem Umkehrgang-Zweischneckenmodul 10 kombiniert, um eine Axialkompression der Masse zu erzielen,
• – Mittel zum Entnehmen der Flüssigphase in Höhe der Zone Z₃, das einen Filter 11 und einen Flüssigkeitsausgang 12 miteinander kombiniert (wird dann verwendet, wenn eine komplementäre Entölung von Kuchen gewünscht wird),
• – und eine Endzone zum Entnehmen der festen Masse Z₄, umfassend ein Direktgang-Zweischneckenmodul 13 und einen Ausgang 14 für Masse (formfertige Kuchen).

The device essentially comprises the following functional zones (seen downstream):

• - A conveyor and compression zone Z ₁ , comprising a cake feed hopper 4 , Direct-flight twin-screw modules with decreasing incline as for 5, and one channel 6 with a pump 7 for injecting water,
• A shear zone Z ₂ which comprises at least one twin-cam disc mixer as in 8,
• - A squeeze and compression zone Z ₃ , the squeeze modules, which are formed by direct-gear twin-screw modules as with 9 with a downstream decreasing slope, with a reverse-gear twin-screw module 10 combined to achieve axial compression of the mass,
• - Means for removing the liquid phase at zone Z ₃ , which has a filter 11 and a liquid outlet 12 combined with each other (used when complementary deoiling of cakes is desired),
• - And an end zone for removing the solid mass Z ₄ , comprising a direct-flight twin-screw module 13 and an exit 14 for mass (ready-made cakes).

With the in 3 The conventional mold shown schematically is to be cold formed as described in the first example. On the one hand, this shape comprises a hollow shape 17 , frustoconical in the example, on a press plate 18 is attached and a removable bottom 19 has to facilitate the molding, and on the other hand a suitable counter shape 20 that on the other plate 21 the press is attached. The correct positioning of the shape and counter shape is done with a centering piece 22 guaranteed. Molding and molding are done cold.

With the in 4 The conventional mold shown schematically is to be thermoformed as described in Example 2 in order to obtain a hollow object with the same shape as in Example 1. This form is that of 3 similar, and only the inner wall of the hollow shape is with a steam hood 23 equipped, and the bottom of a sintered molding 24 is with a steam exhaust duct 25 connected. This shape and counter shape are arranged in a heating press (not shown). In the course of thermoforming, a slight play of approximately 1 mm above the hollow mold is retained so that steam can be drawn off.

With the in 5 The conventional shape shown schematically is to be thermoformed as described in the third example. This shape initially includes a shape 26 that corresponds to that of the desired signs, the bottom of which is a removable base 27 is formed with a sintered molding 28 is equipped with a water vapor extraction duct 29 connected is. The shape also includes a counter shape 30 to the shape 26 cover, this counterform with a sintered part 31 is equipped with a steam exhaust duct 32 connected is. This form and counter form are in a heating press.

EXAMPLE 1

Composition of the used primary mass

In this example is de-oiled Sunflower cake used after the crushing of sunflower seeds becomes; the oil extraction is done by pressing and extracting with hexane. After the extraction the cake has the following composition:

The average D50 diameter of the particles of the raw mass corresponds to 0.65 mm (measured dry).

Mechanical preparation and hydrating the mass to obtain a plastic paste

Hydration, homogenization and breaking down of the mass take place with the help of the twin-screw device according to the already described 1 and 2 (since the cake is completely deoiled, the liquid outlet is not used).

The Speed of the screws is 100 revolutions per minute, the temperature of the device will to 30 ° C regulated and maintained. The cake comes with an injection rate of about 32 kg / h injected into the head. There will be about 32 l / h Water injected.

The generated hydrated mass has a final hydration content of 47% by weight and an average D50 diameter of 0.4 mm (dry measured). It is in the form of a homogeneous plastic paste before and lets model yourself easily.

Forming the paste

100 g paste are in the form of 3 placed. A pressure of 4 MPa is exerted between the mold and the counter mold. The molding takes place cold. After being molded, the part retains its shape.

Drying the molded Part

In In this example, the part was dried in a ventilated at 60 ° C Drying oven during the night. The part hardens and it shrinks determined by 1%. The hollow part obtained can be without deformation filled with earth or gravel become.

To Crushing and rehydrating the part can create a new one Plastic mass undergo a new molding process.

EXAMPLE 2

Composition of the used primary mass

In this example will be a de-oiled Cake used which is obtained after crushing sunflower seeds and its composition and grain size in the raw state with that in 1st example used cakes are identical.

Mechanical preparation and hydration

The Cake is first by crushing (hammer mill homogenized with 0.5 mm grid). The D50 diameter becomes 0.35 mm set.

The Cake is then mixed with water in proportions with which one Water content of 38 wt .-% can be obtained. The mixture will Made for 10 minutes at ambient temperature in a "Perrier" mixer.

thermoforming

100 g of mass are in the form of 4 placed. The press is heated to 160 ° C. A pressure of 5 MPa is applied to adjust the shape and counter shape.

The Form will take about 1 minute after the end of the evacuation of water vapor long to 160 ° C held. Then the part is removed from the mold. It is dry and rigid. No measurable shrinkage is found. The Part needs no further conditioning. In crushed condition and when it comes into contact with earth, the part decomposes and disappears completely after a few weeks.

EXAMPLE 3

Composition of the primary mass

In this example is de-oiled Cake used which is obtained after crushing sunflower seeds whose composition and granule size in the raw state with those of the cake are identical in the previous examples.

Mechanical preparation

The primary mass is homogenized by crushing (hammer mill with 0.5 mm grid). The D50 diameter is set to 0.35 mm.

The initial The water content of the cake is kept (10%).

thermoforming

30 g of mass are in the form of 5 placed. A molding agent is first applied to the sintered molded parts. The temperature of the lower plate of the press is raised to 150 ° C, that of the upper plate set to 180 ° C. A pressure of 20.4 MPa is applied and maintained one minute after the balancing of the temperature of the press plates.

E

Dicke der Probe

Rf

Biegefestigkeit

Em

Elastizitätsmodul

Then the part can be removed from the mold. It is dry, flat and rigid. After solidification, the part does not require any special conditioning. Its mechanical characteristics are listed in the table below. They were measured with a texture meter XTRAD according to the NF EN 310 standard.

e

Thickness of the sample

Rf

flexural strength

em

modulus of elasticity

In one saturated with moisture Milieu, the part is covered with mold and begins to decompose over the course of several weeks.

Claims (12)

Process for the production of a biodegradable, compostable and recyclable article, characterized in that it comprises the following steps: (a) using a sunflower or rapeseed cake with an oil content of less than 20% by weight and a protein content of more than 15% by weight .-% based on the weight of the dry mass, hydrogenated so that a water content between 5 and 55 wt .-% based on the total mass is produced, (b) performing a molding process by pressing the cake mentioned in a mold that that of the desired object and (c) performing heat treatment or drying treatment to solidify the article in its shape. The method of claim 1, wherein a cake with a water content between 10% and 25% based on the total mass is used, and wherein a thermoforming of said cake carried out is brought to a temperature between 130 ° C and 200 ° C during pressing becomes. The method of claim 2, wherein the thermoforming at a pressure essentially between 15 and 25 megapascals. The method of claim 1, 2 or 3, wherein the Sunflower or rapeseed cake before mechanical cutting and subjected to homogenization treatment to give it such Particle size distribution to confer that mean diameter equivalent to D50 particles is between 0.1 mm and 1 mm. Method according to one of claims 1 to 4, wherein at least one partially de-oiled Sunflower or rapeseed cake with an oil content of less than 10 % By weight is used. The method of claim 5, wherein an oil-free Sunflower cake after crushing the sunflower or rapeseed is used. A method according to claim 5, in which a divided and homogenized cake is used which may be de-oiled by passage through a twin-screw device which, seen downstream, shear means ( 8th ), Crushing agent ( 9 ), optionally means for removing the liquid phase ( 11 . 12 ), at least one module with reverse gear ( 10 ) to achieve axial compression of the solid components, and an exit ( 14 ) for said solid components, said twin-screw device with water injection means ( 6 . 7 ) is equipped to adjust the water content of the cake obtained. Method according to one of claims 1 to 7, in which an vegetable fibers of rich sunflower or rapeseed cake becomes. A method according to claim 1 for the cold production of a Item in which a sunflower or rapeseed cake a mechanical Is subjected to dicing and homogenization treatment in order to such a grain size distribution to confer that the mean diameter equivalent to D50 particles is smaller than 1 mm, the cake mentioned has a water content between 25 and 50% is hydrogenated to form a plastic paste Carry out cold-forming the paste mentioned and achieving drying the same until solidification. The method of claim 9, wherein the molding is on a pressure between 1 and 5 megapascals is carried out. Method according to one of claims 1 to 10 for the production of flat objects like signs or plates. Method according to one of claims 1 to 10 for the production of hollow objects like containers or Packagings.