FR2988640A1 - Acoustically and thermally insulated composite material for use in structural element of building e.g. naval building, has core in form of web including bamboo filaments, fibers of product, and bonding agents, and bonded face bonded to core - Google Patents

Abstract

The material has a layer i.e. core, which is in form of a web including bamboo filaments, fibers of a product, and bonding agents. Weight percentages of the bamboo filaments, the fibers of the product, and the bonding agents relative to the weight of the core vary between 20 and 75%, 20 and 75%, and 5 and 30%, respectively. Another layer i.e. thermal or adhesively bonded face, is bonded to the core. The face is a needled web including jute fibers and/or hemp and/or flax and/or vegetable fibers whose weight percentages relative to weight of the face are 5 to 100%. The product is chosen from a group consisting of hemp, flax and jute. The face is covered with a film and/or non-woven layer including vegetable or synthetic or artificial fibers.

Description

The present invention relates to an acoustically and thermally insulating composite material. In real estate, automotive, aerospace, railway and naval construction, thermal and acoustic insulators have long been used. Often these insulators are made of mineral wool or other products that may be harmful during handling and / or use or during destruction. The realization of these disadvantages has pushed the builders to move towards the use of insulation of natural origin. Nevertheless, if these new insulators are ecologically neutral they do not always give satisfaction in terms of resistance to moisture, heat resistance and longevity. We are constantly seeking to manufacture insulators of natural origin and more particularly plant that best meets the aforementioned constraints. To avoid any misinterpretation we indicate our definitions of some technical terms. The term "fiber" refers to a filamentary substance having a length (or "size") more than 10 times greater than its largest dimension in any transverse plane, the transverse planes being the planes intersecting the fiber perpendicular to the direction of its length. B 1 2FRO084 dep The average size of a set of fibers is the arithmetic mean of the lengths of these fibers. The term "film" refers to a generally flexible sheet having a thickness of less than 1 mm. The term "nonwoven" is a felt composed of vegetable, synthetic or artificial fibers with a weight ranging from 15 to 1500 g / m2 and a thickness ranging from 0.5 to 25 mm and produced by the dry, wet or paper process. . A "rigid plate" is a sheet of thickness greater than 5 mm. An object of the present invention is to provide an insulating material meeting the new thermal and acoustic performance constraints. For this purpose, the invention proposes a thermally and acoustically insulating composite material. The insulating composite material according to the invention is characterized in that it comprises at least a first layer called core, that said core is a mat comprising at least bamboo fibers and fibers of a product selected from the group consisting of hemp, flax and jute, and binding agents, in percentages by weight relative to the weight of the core, the bamboo fibers vary between 20 and 75%, the fibers of the product selected between 20 and 75%, 75% and binding agents between 5 and 30%. The applicant holds a patent application FR 11 53942 concerning a composite insulating material essentially using flax fibers. The insulating elements thus obtained have a low rigidity and their handling and use in some applications is not very easy without the addition of a more rigid element. Bamboo fibers are the fastest growing fibers. Bamboo consists of extremely dense and parallel fiber networks. Bamboo culture can absorb large amounts of CO2. This fiber provides superior values in terms of thermal and acoustic insulation. These fibers undergo no chemical treatment and this fiber and therefore completely natural and biodegradable. Bamboo for its cultivation needs only the sun, it produces itself an antibacterial substance and therefore does not require any pesticide for its cultivation. This culture is totally ecological because we do not replant the bamboo, it is cut to about 1m of the ground and pushes back automatically (it avoids to exhaust the resources of the ground). The harvest is done approximately every 5 years. Bamboo fiber has antibacterial, antifungal and antistatic properties. Thus, using an insulation comprising flax fiber and bamboo fiber combines the beneficial effects of two fibers depending on the applications and the environment in which the insulating materials will be used. Bamboo fiber is an ecologically interesting product that can be combined with other natural fibers in place of flax fibers such as hemp fiber or jute. Hemp fibers with a density equivalent to other plant fibers, for example flax, make it possible to obtain more rigid products and better mechanical strength. The hemp fiber comes from the cultivation of hemp which is naturally ecological because this culture is totally without any phytosanitary treatment.

The cultivation of hemp is also a good rotational crop to cut diseases of corn, wheat. This crop is used to rest the soil and improve crop yields later. The cultivation of hemp is a crop with a short cycle (3 months). No irrigation is necessary, no fertilizer or phytosanitary treatment. In order to obtain the hemp fibers, a mechanical defibration is carried out, the purpose of which is to separate the rigid part of the plant (the chènevotte) from the fibrous part which is at the periphery of the plant stem. For ease of this "extraction of fibers" a natural retting on fields allows to dissolve the pectins making it possible to make the link between the fiber and the "wood" of B 1 2FRO084 of the plant. Retting is just a combination of UV and ambient humidity. During this defibration, a so-called paper-quality fiber is obtained (coarse fibers loaded with chenevots). To have a so-called technical fiber a second so-called refining step is necessary. This fiber consists of a "combing" of the fiber and a mechanical cleaning thereof. After refining we obtain a fine and clean technical fiber with a length of between 20 and 70 mm. Jute fibers with a density equivalent to other plant fibers, for example flax, make it possible to obtain more rigid products and better mechanical strength. Of course, fibers picked from a jute field can be used to make the insulation product, but jute bags usually used for the storage of certain products such as coffee beans, cocoa beans and the like can also be recycled. foodstuffs. Firstly, jute sacks are defibered and then jute fibers are recycled to make the insulating material. In summary, the jute fibers provide the insulating product with better rigidity, better water resistance and high resistance to decomposition. In addition, jute is a protective barrier against microbial attack of the plant. Indeed, because of its chemical nature, jute is an extremely resistant material to various chemical agents and to biological degradation. The combination of bamboo fibers with fibers of either linen or jute or hemp combines the intrinsic qualities of these fibers to obtain an insulating material for a specific application. According to one embodiment the composite material comprises at least a second layer called heat-bonded or bonded face to the core, said face is a needled blanket comprising in percentages by weight relative to the mass of the face 5 at 100% of jute fibers and / or hemp and / or flax and / or other vegetable fibers.

The core of such a material which is a topping made of bamboo fibers and fibers either hemp or linen or jute can still in some cases have insufficient rigidity. This soul is in the form of a roll or a panel. The fact of adding by heat-sealing or gluing the faces made of a needle-punched blanket, which is simply or preferably is doubly needled, allows it to increase the rigidity. The composition of the material makes it possible to absorb the ambient humidity and to restore it when the weather conditions allow it. Working with a core and a face improves acoustic and thermal insulation and eliminates sagging over time in vertical installation. According to an alternative embodiment, the core is located between two parallel faces. According to another embodiment the face or faces also comprise binding agents.

The binding agents are selected from two-component polyester fibers, polyethylene fibers, polypropylene fibers, vegetable starch-based thermosizing fibers, thermoplastic powders, resins or a mixture of at least two of these agents. . In a preferred embodiment at least one face is coated with a film and a nonwoven comprising vegetable or synthetic or artificial fibers.

In order to meet certain requirements related to a specific use of the insulating material, at least one face comprises a pulverized agent imparting to it characteristics of water or vapor or moisture impermeability or fire resistance or traction. According to an alternative embodiment, at least one face is coated with a film and / or a nonwoven comprising vegetable or synthetic fibers or artificial fibers.

Preferably the jute fibers have an average size of between 10 and 100 mm. The invention also relates to a construction element for a building or for a motor vehicle or railway or naval building B 12FR0084 dep or for aircraft incorporating less a layer of the material as defined above. The needle punch used for the faces has a density ranging from 400g / m2 to 2000g / m2.

Preferably, the fibers of bamboo and hemp or flax or jute present in the core are an individual content of between 20 and 75%, more preferably between 30 and 55%, in percentages by weight relative to the total mass of the insulating composite material. According to a particular embodiment, the core comprises, in percentages by weight relative to the total mass of said material, more than 60%, preferably more than 80% and / or less than 95%, preferably less than 90%. fiber. - The hemp or jute fiber or flax or bamboo fibers have an average size preferably greater than 15 mm, preferably greater than 30 mm and / or less than 100 mm, less than 80 mm, - the binding agent in the core has a melting point below 200 ° C and / or above 100 ° C.

The binder present in the insulating composite material has a content greater than 2%, preferably greater than 10%, even greater than 15%, and / or less than 50%, preferably less than 40%, less than 30%. %, lower B 12FR0084 dep 20%, in percentages by weight relative to the total mass of the core. Preferably, hemp or flax or jute and bamboo fibers together make up more than 80%, more than 90% or even more than 95% of the total mass of the material. Preferably, the fibers of hemp or flax or jute and bamboo and the binding agent together represent 100% of the total mass of the insulating composite material. A material according to the invention may take various forms, and may especially be present in the form of a flexible product capable of being wound up, called "rollable product", or more rigid, in the form of a panel. A rollable material according to the invention has a thickness before winding preferably greater than 15 mm, greater than 20 mm, greater than 30 mm, preferably greater than 40 mm, even greater than 45 mm and / or, preferably, lower at 500 mm, less than 400 mm, less than 300 mm, less than 250 mm, or even less than 200 mm. A rollable material according to the invention has a length preferably greater than 1 m, greater than 2 m, greater than 3 m, even greater than 4 m and / or, preferably, less than 15 m, less than 12 m, less than 10 m, or even less than 9 m. B 12FR0084 dep A rollable material according to the invention has a width preferably greater than 0.30 m, greater than 0.45 m, greater than 0.55 m and / or, preferably, less than 1 m, less than 0 , 90 m, less than 0.75 m, or even less than 0.65 m. Preferably, a rollable material according to the invention also has a density greater than 10 kg / m3, preferably greater than 20 kg / m3, preferably greater than 30 kg / m3, and / or less than 120 kg / m3, preferably less than 60 kg / m3 and especially less than 40 kg / m3. A panel according to the invention has a thickness preferably greater than 30 mm, greater than 70 mm, greater than 100 mm and / or, preferably, less than 600 mm, less than 400 mm, less than 300 mm, less than 200 mm. A panel according to the invention has a length preferably greater than 0.70 m, greater than 0.90 m, greater than 1.10 m, greater than 1.20 m and / or, preferably, less than 3 m. , less than 2 m, less than 1.50 m, less than 1.30 m.

A panel according to the invention has a width preferably greater than 0.30 m, greater than 0.45 m, greater than 0.55 m and / or, preferably, less than 1 m, less than 0.90 m , less than 0.75 m, or even less than 0.65 m. B 1 2FRO084 dep A panel according to the invention a density preferably greater than 20 kg / m3, preferably greater than 30 kg / m3, preferably greater than 40 kg / m3 and less than 200 kg / m3, preferably less than 150 kg / m3 kg / m3 and especially less than 50 kg / m3. According to a particular embodiment, the invention is in the form of a panel of insulating composite material according to the invention having a large face, or even two large faces, coated (s), at least partially, with a film, of preferably a waterproof film with water vapor. Said film may advantageously be chosen from a composite film, preferably a flexible film, for example a kraft-aluminum paper film, a nonwoven film, a vapor brake or a plastic film. Preferably, said film is made of kraft-aluminum paper. According to another particular embodiment, said insulating composite material is bonded, especially at at least one of its large faces, for example by gluing, heat welding, ultrasound, sewing or any other suitable method, at least a rigid plate. The rigid plate may be selected from plasterboard, gypsum, wood, composite wood, or particle board. These materials make it possible to manufacture bracing panels, finishing, protection against various projections, fire resistance. B 12FR0084 dep A construction element according to the invention may be in the form of a superposition of layers, at least one of the layers being of insulating composite material according to the invention and at least one of the layers being of a complementary material . Such an element may also have a large face, or even two large faces, coated (s), at least partially, a film as defined above. The building element incorporating at least one layer of material may be used for the building, for automotive or railway vehicles or for a naval vessel or for a particular aircraft to provide thermal and / or acoustic insulation. B 1 2FRO084 dep

Claims (10)

REVENDICATIONS1. An acoustically and thermally insulating composite material, characterized in that it comprises at least a first layer called a core, said core is a batt comprising at least bamboo fibers and fibers of a product selected from the group consisting of hemp, flax and jute and binding agents, in percentages by mass relative to the mass of the core, the bamboo fibers vary between 20 and 75%, the fibers of the product selected between 20 and 75% and binding agents between 5 and 30%. 15 2. Material according to claim 1, characterized in that it comprises at least a second layer called thermally bonded side or bonded to the core, said face is a needled mat comprising in percentages by weight relative to the mass of the face 5 100% jute and / or hemp fibers and / or flax and / or other vegetable fibers. 3. Material according to claim 2, characterized in that the core is located between two parallel faces. 4. Material according to one of claims 2 or 3, characterized in that the face or faces also comprise binding agents. 30 B 12FR0084 dep 5. Material according to one of claims 1 to 4, characterized in that the binding agents are chosen from two-component polyester fibers, polyethylene fibers, polypropylene fibers, thermofoil fibers based on vegetable starch. thermoplastic powders, resins or a mixture of at least two of these agents. 6. Material according to one of claims 2 to 5, characterized in that at least one face is coated with a film and a nonwoven comprising plant fibers or synthetic or artificial. 7. Material according to one of claims 2 to 6, characterized in that at least one face comprises a pulverized agent giving it characteristics of water-tightness or steam or moisture or resistance to water. fire or catch. 8. Material according to one of claims 2 to 7, characterized in that at least one face is coated with a film and / or a nonwoven comprising plant fibers or synthetic or artificial. 9. Material according to one of claims 1 to 8, characterized in that the bamboo fiber B 12 FR0084 deposition of the selected product have an average size of between 10 and 100 mm. 10. Construction element for a building or for a motor vehicle or a railway vehicle or for a naval building or for an aircraft incorporating at least one layer of the material according to one of claims 1 to 9. B 1 2FRO084 dep