OA21402A - Composite materials based on plastics and plant fibers, particularly rice husks, their manufacturing processes and their uses. - Google Patents

Abstract

The present invention relates to the field of composite materials. The invention also relates to the method for obtaining such a material and to the use of such a material for making roof coverings and for the production of furniture or similar products, said material is obtained from the following steps; a) fusion of recycled and/or new plastic films or plastic granules with fibers of plant origin, b) homogeneous mixing and kneading of said plastics and fibers by the addition of adjuvant until obtaining aggregates through an extruder or not, c) thermoforming of the aggregates either by an extrusion line or by mechanical pressure under a heated mold press to produce materials with variable dimensions and shapes required. The method according to the invention makes it possible to obtain an ecomaterial having mechanical, thermal, water and acoustic properties and has the advantages of being more resistant, more flexible, more insulating and waterproof.

Description

The present invention relates to the field of composite materials. The invention also relates to the process for obtaining such a material and to the reuse of such a material to produce roof coverings and for the production of furniture or similar products.

Generally speaking, composite materials are either materials reconstituted from isolated products of plant origin, or isolated products of plant origin, mixed with materials of synthetic origin, such as polymers.

We know from W02006/031522 composite materials based on wood materials and non-wovens reinforced with a “B” stage binder. Basic nonwoven fabrics are known, for example, from US-A-5,837,620, US-A-303,207 and US-A-6,331,339. Materials are also known in the state of the art composites obtained from plastics and/or plant materials.

If the technologies described above have the merit of being developed either to allow the manufacture of construction materials or the manufacture of false ceilings, they still have limits. In fact, composite materials present a form of porosity which leads to acoustic noise. These are therefore less insulating and water-repellent materials. It was therefore a question of optimizing already known products with regard to their technological application properties and manufacturing processes.

This goal is achieved by a composite material composed of a reinforcement made of material of synthetic origin and material based on fibers or a mixture of fibers, the fiber(s) coming from waste of plant origin.

According to one embodiment of the invention, the material is obtained from the following steps; a) fusion of recycled and/or new plastic films or plastic granules with fibers of plant origin, b) homogeneous mixing and kneading of said plastics and fibers by the addition of adjuvant until aggregates are obtained through a extruder or not, c) thermoforming of the aggregates either by an extrusion line or by mechanical pressure under a heated mold press to produce materials with variable dimensions and shapes requested.

The process according to the invention makes it possible to obtain an eco-material having mechanical, thermal, water and acoustic properties and has the advantages of being more resistant, more flexible, more insulating and waterproof.

The plant materials according to step a) are rice husks or any other type fibers, crushed or not.

According to a preferred embodiment of the invention, the adjuvants used are dyes or thermal stabilizers or flame retardants.

Page 1 of 8

A process for manufacturing the composite material according to the invention consists, in a first step, of adding fibers to the elements to the plastic granules to obtain compounds resulting from the mixture-kneading step, and of continuing the thermoforming or mixing steps. extrusion to obtain the desired type of material.

According to another advantageous variant, the ratio by weight of plant fibers/plastic materials is between 15% and 80%, preferably between 20% and 75%.

The particularity of combining rice husks and plastic materials is that the materials obtained can be used for several uses, that is to say either for roof coverings, for false ceilings, or for floor coverings. or wall, or for the production of furniture or similar products. Indeed, rice husks are lignocellulosic biomasses with fibers that are very resistant to heat (heat > 180°C). They constitute a good binder for mixing with molten plastic granules (PE/PP/PET). They have a density of 120 kg/m ³ , unlike plastic granules whose density is 950 kg/m ³ . This makes it possible to obtain, after a homogeneous hot mixture at a temperature varying between 160 - 250°C at a well-studied percentage, a light, resistant and insulating material to ensure thermal comfort within homes.

Also from a nutritional point of view, rice husks have a low digestibility rate, so they are not used for livestock feed. Hence their relative abundance. The use of plastic materials offers a better alternative for the recovery and recycling of plastic waste which causes pollution of soils and waterways as well as the loss of a good number of livestock due to indigestion of said material. This therefore constitutes an effective means of combating environmental pollution, at the same time as it allows the manufacture of eco-friendly materials.

The present invention will be better understood and its advantages will become apparent from the following steps which illustrate it, without in any way limiting it.

Step 1: obtaining the raw material

Plastic materials can be new or recycled, in the form of granules. To obtain recycled material, plastic waste is collected, sorted, crushed then washed and drained before undergoing densification.

The plant fibers, preferably rice husks, are crushed and/or sifted.

Step 2: mixing and mixing

This step consists of mixing plastic granules and plant fibers in a mixer followed by homogeneous mixing with, optionally, additives such as powdered dyes, thermal stabilizers or flame retardants, to

Page 2 of 8 obtaining compound materials with the desired coloring, preferably iron oxide, and to ensure the strengthening of the mechanical, thermal and water properties of said composite materials.

Step 3: thermoforming or extrusion

Once the mixture has been made homogeneous, it is transformed into aggregates through an extruder or not. Then, the aggregates obtained are processed, either by an extrusion line to produce materials with variable dimensions and shapes, or by mechanical compression under a heated mold press to produce materials with variable dimensions and shapes.

According to a variant of the invention, the compounds are poured inside the mold then conveyed into a thermofurnace at a temperature between 180 and 250°, and using a press said softened compounds are compacted to obtain panels of variable shapes depending on the mold used.

According to another variant of the invention, the compounds are poured inside the extrusion line which, through the extrusion screws, heat said compounds to produce compactable materials of rectangular, square, circular or any other shape. .

According to another preferred variant of the invention, different types of composite materials can be obtained from the compounds poured inside the thermofurnace, said type of material can be obtained depending on the type of mold. This can include composite materials such as sanitary facilities, office furniture, school furniture, floor coverings and walls.

According to another preferred variant of the invention, composite materials of the beacon type can be obtained by applying the principle of extrusion and using the appropriate mold.

Thus, as shown in tables 1 & 2 as well as the figures on plates I/II, ΙΙ/Π, the recycled plastic granulated composition PE loaded with 20 to 30% in rice husks makes it possible to obtain an eco-material having the following properties:

mechanical properties o an average density of 1.2;

o a specific weight of 14 kg/ ^m2 ;

o and a bending breaking strength of 16 N/mm ² ;

thermal properties o a thermal conductivity of 0.34 W/mK;

o a volumetric thermal capacity of 2.733 MJ/m ³ .K o and a surface thermal expansion of 2.35 ^E -04 m ² /m ^2O C

Page 3 of 8 water properties o perfect waterproofing with a waterproof rate of approximately 99.2 and a zero absorption rate.

acoustic properties.

The materials thus obtained, consisting of a homogeneous mixture of different percentages of PE plastic granules and rice husks, can be used for the production of roof coverings, and/or used in the manufacture of furniture of all kinds, or for the manufacture of all other products. The composition giving the best compromise between Young's modulus (plate I/II) and elastic stress (II/II) is that 10 whose rice husk load is between 20% and 30%.

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BOARD Ι/Π

Young's modulus of traction 1So - 1UUU onn - oUU CO o> cnn _ · “ ► Emax UUU ΛηΑ - _k < 1 k « k ► ♦ Average E 4UU ‘ΪΠΛ - ZUU 0.00% 1.00% 5.00% 10.00% 20.00% 30.00% 50.00% % in rice husk

Figure 1: Trend curve of Young’s tensile moduli, as a function of % in rice husk

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BOARD Π/Π

Elastic bending stress

% rice husk

Figure 2: Tensile elastic stress trend curve, as a function of % rice husk

Claims (12)

1. Composite material characterized in that it is obtained from a mixture of materials of synthetic origin and materials based on fibers or a mixture of fibers, the fiber(s) coming from waste of plant origin more particularly rice husks. 2. Composite material according to claim 1, characterized in that the materials of synthetic origin are made up of new or recycled plastic materials in the form of granules or not, the materials based on plant fibers being made up of crushed rice husks and/or or sifted with optionally additives such as powdered dyes, heat stabilizers or flame retardants. 3. Composite material according to claims 1 and 2, characterized in that the ratio by weight of plant fibers / plastic materials is between 15% and 80%, preferably between 20% and 75%. 4. Composite material according to claims 1, 2 and 3, characterized in that said material has mechanical, thermal, water and acoustic properties. 5. Composite material according to any one of the claims, characterized in that from the point of view of mechanical properties said material has an average density of 1.2, a bending breaking strength of 16N/mm2. 6. Composite material according to any one of claims, characterized in that from the point of view of thermal properties, said material has a thermal conductivity of 0.34w/mK, a volumetric thermal capacity of 2,733 MJ/m3K and a thermal expansion surface area of 2.35E-04 m ² /m ^2O C 7. Composite materials according to any one of claims, characterized in that from the point of view of water properties, said material has a waterproofness with a waterproof rate of approximately 99.2 and a zero absorption rate. 8. Process for manufacturing material according to any one of claims, characterized in that it comprises the following steps: a) fusion of recycled and/or new plastic films or plastic granules with fibers of plant origin, b) homogeneous mixing and kneading of said plastics and fibers by the addition of adjuvant until compound materials are obtained c) thermoforming or extrusion of the compounds to produce composite materials with variable dimensions and requested shapes. 9. Process for manufacturing composite material according to any one of the claims, characterized in that the compounds are poured inside the mold then conveyed to a thermofurnace at variable temperature, and using Page 7 of 8 of a press, said softened compounds are compacted to obtain panels of variable shapes depending on the mold used. 10. Process for manufacturing composite material according to any one of claims, characterized in that the compounds are poured inside the extrusion line which, through the extrusion screws, heats said compounds to produce compactable materials of shape rectangular, square, circular or any other shape depending on the type of mold used. 11. Process for manufacturing composite material, according to any one of the claims, characterized in that different types of composite materials are obtained from the compounds poured inside the thermofurnace by adding at the end of the chain the type of desired mold. 12. Use of the composite material according to any one of the claims, characterized in that said softened compounds allow the manufacture of roof coverings, false ceilings, floor coverings, sanitary facilities, furniture, beacons.