Composition for the production of biodegradable products from bran and corresponding molding process

Description

[0001] The invention relates to a composition for the manufacture of biodegradable products from bran, more particularly wheat bran, and the invention also relates to the shaping for obtaining the products.

[0002] The manufacture of bran-based products, and more particularly wheat bran, is known. For example, WO 01 / 39612 A1 discloses a method for manufacturing biodegradable molded parts in which wheat bran is used as the primary raw material. Other examples of biodegradable compositions are disclosed in JP H11 166055 A and EP 1 500 683 A1. JP H11 166055 A discloses a biodegradable article having high mechanical strength obtained by molding a material containing wheat bran and a natural or synthetic organic compound, which may be chitin. EP 1 500 683 A1 discloses a composition for the manufacture of biodegradable molded parts, in particular tableware containing free bran, in particular that of wheat, constituting a selected bran fraction with a particle size of 0.01 to 2.80 mm containing from 7% to 45% of structurally bound water in the form of moisture.

[0003] The products envisaged are essentially products such as tableware. Indeed, disposable tableware made from petroleum products is no longer acceptable and there is an active search for tableware that is biodegradable and made from renewable raw materials. The products according to the present invention are biodegradable.

[0004] Wheat bran tableware has already been produced, but this type of product faces significant constraints and problems during long-term storage. Indeed, the mechanical parameters are important because the product must be mechanically rigid to be held and to withstand a load. The product must also respond favorably to exposure to microwave radiation during heating operations of food materials contained in the product.

[0005] Another constraint is related to storage. Indeed, many days or even weeks often pass between the manufacture of products and their use. These products are therefore stored and since they are made from organic materials of natural origin and have a certain humidity level, mold can develop. These microorganisms can present a certain danger to humans, particularly Claviceps responsible for ergo of wheat or rye.

[0006] During the implementation of the composition by the process according to the present invention, it was found that the products on the market require long mixing times, high processing temperatures by pressing and finally very long cooling steps for certain processes.

[0007] The object of the present invention is to propose a composition based on wheat bran as a raw material for the manufacture of a thermo-molded product, the parameters of which make it possible to meet the requirements of mechanical strength, resistance to temperatures, exposure to microwaves, and above all to delay the appearance of mold. The object of the invention is also to propose a process allowing the production of products at manufacturing prices acceptable to the market, which consume less energy.

[0008] A thermo-molded product within the meaning of the invention has undergone a thermoforming step. It is a thermoformed product.

[0009] According to a first aspect, the present invention describes a composition for the manufacture of a thermo-molded product comprising wheat bran with a particle size of between 200 and 800 µm and a stabilized moisture content of between 5 and 15% by weight of bran as well as water and at least one agent capable of combating the appearance of mold, the agent intended to combat the appearance of mold being chosen from sodium benzoate, potassium sorbate, thiobendazole, and ascorbic acid.

[0010] The addition of a particular agent to the raw material composed of wheat bran makes it possible to obtain an improved thermo-molded product from this composition. A thermo-molded product according to the invention has better mechanical resistance and does not undergo degradation during the thermoforming step.

[0011] According to a particular embodiment of the present invention, the composition further comprises keratin in a proportion of between 2 and 8% by weight of the total composition. The addition of keratin to raw materials composed of wheat bran makes it possible to obtain better mechanical and thermal resistance, delays the appearance of mold on the finished product, and gives a shiny appearance to the surface of the product.

[0012] According to yet another characteristic of the invention, the composition comprises chitin in a proportion of between 0.5 and 2% by weight of the total composition. The addition of chitin to raw materials composed of wheat bran makes it possible to obtain better mechanical resistance and promotes the migration of moisture into the product; the appearance will also be improved, giving the finished product a shiny surface appearance.

[0013] According to another particular embodiment of the present invention, the composition comprises casein in a proportion of between 0.5 and 3% by weight of the total composition. The addition of casein to raw materials composed of wheat bran makes it possible to obtain better mechanical and thermal resistance, delays the appearance of mold on the finished product, and gives a shiny appearance to the surface of the product.

[0014] In a second aspect, the present invention also describes a method for manufacturing at least one thermo-molded product from the composition according to the invention comprising the following steps: Mixing and humidifying the composition for a period of between 2 and 30 minutes, preferably 5 minutes, Extrusion of the mixed composition thus forming a plate, Heating of the plate between 50° and 250°, preferably between 70° and 80°, Thermoforming and cutting according to the shape of the desired finished product with simultaneous pressing at the heating of between 5 and 500 kg / cm2 for a period of 10 to 600 seconds, preferably 50 kg / cm2 for 300 seconds, and Demolding and recovery of at least one finished product.

[0015] According to one embodiment of the method, the thermoforming step is carried out using a press capable of thermoforming a plate of the composition.

[0016] According to a characteristic of the method according to the invention, the press is capable of thermoforming four finished products.

[0017] According to one embodiment of the method, the press is capable of thermoforming four thermo-molded products from a plate of the composition.

[0018] According to one embodiment of the method, the mixing step is carried out in a mixing and humidifying screw.

[0019] According to a feature of the method according to the invention, the composition at the outlet of the mixing and humidification screw is placed in a feed hopper. The use of a hopper makes it possible to ensure that excessively large grains of wheat bran do not end up in the composition.

[0020] According to one embodiment of the method, the extrusion step is carried out by means of first heating compacting rollers and second shaping rollers.

[0021] According to one embodiment of the method, the heating step is carried out on a continuous transfer and post-treatment belt also suitable for vaporization or the addition of a layer of surface additives.

[0022] In a third aspect, the present invention also describes a thermo-molded product obtained by the manufacturing method according to the invention.

[0023] [ Fig. 1 ] is a perspective view of an embodiment of the method according to the invention.

[0024] It should be noted that in these figures the structural and / or functional elements common to the different variants may have the same references. The present invention is now described using examples which are purely illustrative and in no way limitative of the scope of the invention.

[0025] The biodegradable composition 1 according to the present invention is based on wheat bran. The first essential parameter is the particle size of the bran used. Thus, composition 1 according to the present invention uses a particle size of between 200 and 800 µm. This particle size is chosen to obtain the desired characteristics.

[0026] Process 2 consists of introducing wheat bran of the selected particle size with a stabilized moisture content of between 5 and 15% by weight of bran, in this case 14%, into a mixer. A quantity of demineralized water of 7.75% water is added to the mixer to produce a paste, followed by stirring for a period of between 2 and 30 minutes, more particularly 5 minutes. A paste is obtained with the hydrated bran.

[0027] The method 2 then consists of ensuring thermoforming under pressure of this paste, in particular in a press, and at temperature. For this purpose, a mold 3, in this case of parallelepiped shape, is filled with the composition 1 in the form of paste, coming out of the mixer 4 and the pressing is carried out at a rate of pressure between 5 and 500 kg / cm2, in this case 50 kg / cm 2< . The pressing time is between 10 and 600 seconds, more particularly 300 seconds. Heating is provided simultaneously with the pressing and the temperature varies from 50°C to 250°C, a temperature between 70 and 80°C is retained. Tests are conducted with a pressure of 50 kg / cm 2< , a temperature between 70 and 80°C and a pressing time of 300 seconds. The demolding of the plate is immediate. It can be seen that no cooling is necessary.

[0028] Process 2 and composition 1 avoid cooling and allow for high-quality, instant demolding.

[0029] The finished product 5 obtained from composition 1 according to the present invention once shaped by thermo-pressing under the conditions of process 2 has a moisture content of between 2 and 15% by weight of water. Under simple storage conditions, that is to say without special precautions, in particular conditions in which there may be moisture saturation, the appearance of mold on the products obtained by thermoforming, from composition 1 according to the present invention, implemented according to process 2 of the present invention, can be observed from 13 days.

[0030] In order to combat the appearance of mold and to allow a longer storage life, one and / or more of the following compounds are included in composition 1: Sodium Benzoate Potassium Sorbate Thiobendazole Ascorbic Acid Oleic Acid, notably marketed under the name "Radiacid Oléon 0134".

[0031] No change in the color of product 5 is observed due to these compounds. With the spraying of Potassium Sorbate at a rate of 0.6% by weight of the bran / water mixture, the duration of appearance is extended to 120 days.

[0032] According to particular forms of the invention, additional agents to those chosen from sodium benzoate, potassium sorbate, thiobendazole, and ascorbic acid, are added to composition 1 in order to prevent the appearance of mold and / or to increase the mechanical resistance of the finished product, to limit the migration of moisture and / or also to improve the visual appearance of the finished product. These agents described below are added alone or in combination with each other and with the agents chosen from sodium benzoate, potassium sorbate, thiobendazole, and ascorbic acid.

[0033] According to a first example of implementation, the addition of 2 to 8% of keratin to the mass of raw materials composed of wheat bran allows for better mechanical and thermal resistance, delays the appearance of mold on the finished product, and gives a shiny appearance to the surface of the finished thermoformed product.

[0034] According to another embodiment, chitin is an agent compatible with the present invention.

[0035] Regarding chitin, the optimal rate of addition to raw materials is lower, namely between 0.5% and 2%. The addition of chitin improves the mechanical strength of the finished product, promotes moisture migration into the product and the appearance of the finished product will also be improved by providing a shiny surface.

[0036] In order to provide the best production yield of the desired final product 5 by limiting losses and increasing the production rate, a process 2 for manufacturing the product from the composition 1 according to the invention was implemented.

[0037] There figure 1 schematically illustrates an embodiment of method 2 according to the invention.

[0038] The first step involves mixing the enriched raw materials forming composition 1. The enriched raw materials, namely wheat bran, water and at least one agent chosen from sodium benzoate, potassium sorbate, thiobendazole, and ascorbic acid, are therefore introduced into a mixing and humidifying screw 4 which acts as a mixer 4.

[0039] The composition 1 thus mixed can then be placed in a feed hopper 6. Optionally, this hopper 6 can also heat the mixture.

[0040] Then, according to an extrusion step of process 2, the mixture of raw materials passes through compacting heating rollers 7 and also through shaping heating rollers 8.

[0041] The composition 1 in the form of a plate is then intended to be heated. This step can take place on a continuous transfer and post-treatment belt 9. Other operations such as hot polymerization or humidification can take place on this belt 9.

[0042] A guillotine 10 is arranged downstream of the belt 9 in order to cut the plate into several plates suitable for thermoforming.

[0043] Pieces of plate are then conveyed via a discontinuous transfer belt 11 to the thermoforming and cutting station 12. This step allows the shaping of finished products 5 by means of a heating press 13. Advantageously, several molds 3 can be arranged at this station 12 according to the dimensions of the plate and the finished format of the desired product 5. According to one embodiment of the invention, plates are thermoformed from the composition 1 according to the invention

[0044] Finally, the last step of demolding and recovery of the finished product 5 can be carried out using an unloading robot 14, for example with a suction cup manipulator.

[0045] According to one embodiment of the method 2, a storage cart 15 for the finished products 5 is provided.

[0046] This example of the previously described synoptic diagram makes it possible to obtain increased efficiency in the manufacturing process of thermo-molded products.

[0047] According to an example of the implementation of the process for the manufacture of plates, 30-second cycles can be implemented with four plates with a diameter of 228 mm per cycle, i.e. 480 plates available in one hour.

Claims

1. A composition (1) for producing a thermo-molded product (5), characterized in that it comprises wheat bran with a particle size of between 200 and 800 µm and a stabilized moisture content of between 5 and 15% by weight of bran, as well as water and at least one agent capable of combating the appearance of mold, the agent intended to combat the appearance of mold being selected from the following compounds: - Sodium benzoate. - Potassium sorbate. - Thiobendazole. - Ascorbic acid. - Oleic acid.

2. The composition (1) according to the preceding claim, characterized in that the bran has a stabilized moisture content of 14% and in that the water is present in the composition in an amount of 7.75%.

3. The composition (1) according to one of the preceding claims, characterized in that potassium sorbate is added by spraying in an amount of 0.6% by weight of the mixture.

4. The composition (1) according to any one of the preceding claims, comprising keratin in a proportion of between 2 and 8% by weight of the total composition.

5. The composition (1) according to any one of the preceding claims, comprising chitin in a proportion of between 0.5 and 2% by weight of the total composition.

6. The composition (1) according to any one of the preceding claims, comprising casein in a proportion of between 0.5 and 3% by weight of the total composition.

7. A method (2) for producing at least one thermo-molded product (5) from the composition (1) according to one of claims 1 to 6, comprising the following steps: - Mixing and moistening the composition (1) for between 2 and 30 minutes, preferably 5 minutes, - Extruding the mixed composition (1) to form a plate, - Heating the plate to between 50° and 250°, preferably between 70° and 80°, - Thermoforming and cutting to shape according to the desired finished product (5) with simultaneous pressing under heating of between 5 and 500 kg / cm2 for a duration of 10 to 600 seconds, preferably 50 kg / cm2 for 300 seconds, and - Demolding and recovering at least one finished product (5).

8. The method (2) according to the preceding claim, wherein the thermoforming step is carried out by means of a press (13) capable of thermoforming a plate of the composition (1).

9. The method (2) according to the preceding claim, wherein the press (13) is able to thermoform four thermo-molded products (5) from a plate of the composition (1).

10. The method (2) according to one of claims 7 to 9, wherein the mixing step takes place in a mixing and humidifying screw (4).

11. The method (2) according to the preceding claim, wherein the composition at the outlet of the mixing and humidifying screw (4) is fed into a feed hopper (6).

12. The method (2) according to one of claims 7 to 11, wherein the extrusion step is carried out by means of first heated compaction rollers (7) and second forming rollers (8).

13. The method (2) according to one of claims 7 to 12, wherein the heating step takes place on a continuous-transfer and post-treatment belt (9) which is also suitable for spraying or adding a layer of surface additives.

14. A thermo-molded product (5) obtained by the production method according to one of claims 7 to 13.