Layered high porosity material

Abstract

The present invention relates to a layered, high-porosity material having a composite surface layer comprising a structural material and a polyester derived from an aliphatic polyol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having 3 to 15 carbon atoms, the surface layer being bonded to the high-porosity layer of the structural material. Compared to a high-porosity material without the composite surface layer, the material has, among other things, improved surface properties and improved bending stiffness, while maintaining both thermal and acoustic protective properties. The material can be used, for example, as a protective material, a filtration material, or in hydroponics.

Description

[Technical field]

[0001] The present invention relates to a layered high-porosity material. In particular, the present invention relates to a layered high-porosity material provided with a composite surface layer. It has been found that the layered high-porosity material according to the present invention exhibits improved properties compared to a high-porosity material not having said layer. [Background technology]

[0002] Many Blocking The insulation materials are Blocking Whether the material is for thermal or acoustic insulation, it is a high porosity material. Blocking The material essentially relies on stagnant air being trapped within a solid structure, for example between fibers, particles or layers. Blocking material (In this specification, "protective material" is to be read as "blocking material.") Examples are mineral or glass wool mat and plate materials, whether curved or flat, or based on polymers, such as polyurethane. A recent development is the use of high porosity plate materials based on renewable cellulose-based materials, such as hemp, flax, cotton, metis and paper / cardboard, as well as materials of animal origin, such as wool or down. Most of these high porosity materials do not have structural strength or bending stiffness. As a result, they are used in combination with construction frames and generally need to be used in combination with a surface covering, such as a surface covering of plasterboard or other board-like materials, to provide, inter alia, mechanical strength, fire resistance and a surface structure that can be painted, wallpapered or otherwise provided with an attractive visual appearance.

[0003] However, the combination of a flexible high porosity protective material with a separate board cladding has several disadvantages. The fact that at least two materials must be installed separately necessitates having an installation process with at least two steps, thereby requiring more manpower. Furthermore, it requires additional material. Additionally, the use of a solid (non-porous) board material may negate any sound absorbing properties of the protective material. Furthermore, it may have a detrimental effect on the temperature / moisture and other climate regulating properties of the cellulose-based material, resulting in increased CO 2 Also, most drywall and wood-based panels are under scrutiny because they can emit radioactive radon gas and formaldehyde gas, which is carcinogenic and toxic. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, there is a need in the art for a high porosity material that has increased mechanical strength and allows for the elimination of the use of cover plate materials while addressing the problems listed above. This new material may also find application in other situations where high porosity materials are used, such as filtration and hydroponic applications. [Means for solving the problem]

[0005] The present invention relates to a layered, high-porosity material having a composite surface layer comprising a structural material and a polyester derived from an aliphatic polyol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having 3 to 15 carbon atoms, the surface layer being bonded to the high-porosity layer of the structural material.

[0006] It has been found that, compared to the high porosity structural material itself, the material provided with the composite surface layer has increased mechanical strength. Furthermore, it may be possible to use the material without a surface coating. It may also reduce the need for support by a mechanical frame. Further advantages of the material according to the invention will become apparent from the further specification.

[0007] It is noted that WO 2012 / 140238 describes the use of polyester polymers derived from aliphatic polyols and aliphatic polycarboxylic acids having 2 to 15 carbon atoms as coatings or in the manufacture of laminates, and this reference does not disclose providing a high porosity material provided with a composite surface layer of polyester.

[0008] Preferred embodiments of the present invention, together with their associated advantages, will be discussed in more detail below.

[0009] The invention is illustrated by the accompanying figures without being limited in or by them. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 shows a diagram of a panel according to the invention and its starting materials, where the difference in its self-supporting properties can be seen. [Diagram 2] FIG. 2 shows the strength of the surface of a panel according to the invention. [Diagram 3] Figure 3 shows an example where a beam is fitted between two panels. [Figure 4] FIG. 4 shows the free-standing construction of a set of panels within a frame. [Diagram 5] FIG. 5 shows a panel provided with a fabric facing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The layered high porosity material has a composite surface layer comprising a structural material and a polyester, the surface layer being bonded to the high porosity layer of structural material.

[0012] The presence of a composite surface layer combined with a layer of structural material is a very important feature of the present invention. It means that when looking at a cross-section of a layered material according to the present invention, some of the material contains the polyester and some of the material does not contain the polyester. In other words, a composite surface layer containing polyester can be distinguished from a layer of structural material that does not contain polyester. The boundary between the two layers can be easily determined by visual inspection or by analyzing the polymer content of the layers at different positions in the material. The boundary can be identified by a step change in polymer content over a short distance, for example an increase in polymer content of at least 5 times over a distance of 2 cm, optionally over a distance of 1 cm, optionally over a distance of 0.5 cm, optionally over a distance of 0.2 cm.

[0013] The composite surface layer may be present on one side of the material or on two or more sides of the material. For example, if the material has a panel-like shape, i.e., the length and width of the material are significantly greater than the thickness, a composite surface layer may be present on both major sides of the material. In that case, a layer of structural material is sandwiched between two composite surface layers and thus may also be considered a core layer. It is also possible, and may be preferred, to provide a composite layer on one or more sides of the panel.

[0014] The layered high porosity material can be made from conventional high porosity structural materials used in the art as thermal and / or noise protection materials. Examples are panels and mats, whether flat or molded, based on ceramic wool, e.g. glass wool and stone wool, polymer-based panels, cellulose-based panels, and materials based on animal-based products, e.g. wool, feathers and down. Of course, the high porosity material used in the present invention can also include mixtures of various components, e.g. cellulose-based materials combined with stone wool or glass wool, etc. The starting material can be flat or curved, e.g. in the form of a (half cylinder), when used to protect curved surfaces.

[0015] The starting material has a high porosity, for example a porosity of at least 0.5, in particular at least 0.6, more in particular at least 0.7, even more in particular at least 0.8. As a general upper limit, a value of at most 0.995, in particular at most 0.98, can be mentioned. The porosity can be calculated from the density of the high porosity material itself, i.e. blanket or panel, and the density of the composition from which it is constructed, for example glass, stone, polymer or cellulose-based material. Thus, the porosity reflects the volume of voids (which may be filled with gas, e.g. air) in the material relative to the total volume of the material. The values ​​given above also apply to the high porosity layer of the construction material of the layered high porosity material according to the invention. Consequently, the porosity of the layered high porosity material can be calculated from the density of the layered high porosity material and the density of the materials that construct the layered high porosity material.

[0016] The cellulose-based material can be based on any cellulose-containing based material. Examples include wood pulp and paper, including cardboard. In one embodiment, the cellulose-based material is derived from so-called virgin pulp, which is obtained directly from the wood pulping process. This pulp can be derived from any plant material, but mostly from wood. Wood pulp is derived from softwood trees, such as spruce, pine, fir, larch and hemlock, and hardwoods, such as eucalyptus, poplar, aspen and birch. In one embodiment, the cellulose-based material includes cellulose materials derived from recycled paper, such as cellulose pulp obtained from recycled books, papers, newspapers and periodicals, egg cartons, and other recycled paper or cardboard products. A combination of cellulose sources can also be used. The cellulose-based material can also be derived from sources such as flax, hemp or cotton, and other renewable plant-based materials. The term "based on a cellulose-based material" is intended to mean that the object contains at least 50% by weight of cellulose material derived, for example, from a source such as new or used paper, new or used cardboard, wood or any form of other plant material, or a combination thereof. In particular, the object or container contains at least 70% by weight, more in particular at least 80% by weight, of cellulose material.

[0017] The starting material is often in the form of a layer, sheet, mat, or panel, all of which are synonymous in the context of this specification for shapes in which the length and width of the material are significantly greater than its thickness.

[0018] Generally, the starting material has a thickness of at least 0.5 cm, in particular at least 1 cm. As a general upper limit, a value of up to 40 cm may be mentioned. It may be preferable for the starting material to have a thickness in the range of 1 to 30 cm, in particular 2 to 15 cm.

[0019] The width and length of the starting material are not critical to the present invention. Both of them are generally at least three times the thickness of the starting material, for example at least 30 cm, in particular at least 50 cm. The width is generally not more than 4 meters, in particular for practical purposes up to 2 meters. The length of the material can be indefinite, where the material is produced in a continuous process. For practical purposes, the length can be up to 20 m, in particular up to 15 meters, for example up to 8 meters, often up to 4 meters, depending on the application.

[0020] The same dimensions apply to layered high porosity materials according to the present invention.

[0021] The layered high porosity material includes a layer of structural material and a composite surface layer comprising structural material and polyester. The composite surface layer is bonded to the layer of structural material via the structural material. For example, when the high porosity material is a stone wool mat, the composite surface layer is made of stone wool and a specified polyester, and the composite surface layer is bonded to the layer of structural material via stone wool fibers. In other words, the structural material is continuous across the interface between the layer of structural material and the composite surface layer comprising structural material and polyester.

[0022] The composite surface layer generally has a polymer content in the range of 50% to 99% by weight, more particularly in the range of 70% to 95% by weight, calculated based on the weight of the composite surface layer.

[0023] The composite surface layer generally has a porosity in the range of 0.01 to 0.99, in particular in the range of 0.4 to 0.95. The porosity of the composite layer can be calculated from the density of the composite layer and the density of the polymer and structural material in the composite layer. The porosity can remain reasonably high even when it is reduced compared to the porosity of the starting material and the layer of structural material of the layered material. This means that the sound absorbing properties of the structural material are at least partially maintained. This differs from the situation in the prior art, where the provision of a plate material on the front side of a protective material substantially affects the sound absorbing properties of the material.

[0024] The porosity of the layered high porosity material of the present invention is still relatively high, for example at least 0.5, particularly at least 0.6, more particularly at least 0.7. As a general upper limit, a value of at most 0.98, more particularly at most 0.95, can be mentioned. Due to the high porosity in the product, its protective properties are maintained to a large extent, both for heat and sound. Furthermore, the high porosity in the product is achieved by a lower panel weight, which is attractive for many reasons, including the handling properties, transportation, etc. of the panel.

[0025] It has been found that the provision of the composite surface layer makes it possible to increase the properties of the high porosity material, such as bending stiffness, whilst retaining an overall high porosity in the final product, thereby ensuring that protective properties are retained. More particularly, it has been found possible to obtain materials in which the porosity of the final product is in the range of 75-99.5%, in particular in the range of 80-99.5%, more particularly in the range of 85-99.5%, compared to the porosity of the starting product.

[0026] The thickness of the composite surface layer is generally in the range of 1 mm to 40 mm, depending on the overall thickness of the layered high porosity material. A composite layer having a thickness of less than 1 mm is generally too thin to provide the desired surface structure. A thickness of more than 40 mm generally does not provide further improved properties and only increases the weight of the material. The composite surface layer may preferably have a thickness in the range of 2 to 30 mm, in particular 4 to 15 mm.

[0027] Thus, layered materials according to the present invention have one or more composite surface and backing layers, or core layers.

[0028] Typically, when viewed in cross-section through a layered material of the invention, the one or more composite surface layers will make up up to 50% of the cross-section, and when composite surface layers are provided on both sides of the layered material, the composite surface layers will collectively preferably make up 2-50%, especially 5-40%, of the cross-section.

[0029] If only one surface of the material is provided with a composite surface layer, the composite surface layer preferably constitutes 2 to 30%, especially 5 to 20%, of the cross-section.

[0030] The amount of polymer present in the final product can vary within a wide range. When interpreting the values, it should be taken into account that the starting material is relatively light due to its high porosity. Therefore, a relatively large weight percentage of polymer on the final product may still correspond to a relatively thin surface layer. In general, the amount of polymer in the final layered material ranges from 10 to 95% by weight, more particularly from 25 to 80% by weight, calculated based on the total weight of the layered material.

[0031] The material according to the invention has improved mechanical properties, in particular increased bending stiffness and surface hardness, compared to the material from which it is derived. In addition, it may have more attractive surface properties, in particular increased smoothness. In addition, the mechanical properties are improved while at the same time maintaining the noise cancelling properties of the starting material.

[0032] The present invention uses a polyester derived from an aliphatic polyol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having 3 to 15 carbon atoms.

[0033] The starting materials for the present invention are aliphatic polyhydric alcohols and aliphatic polycarboxylic acids having 2 to 15 carbon atoms.

[0034] The aliphatic polyhydric alcohol used in the present invention has at least two hydroxy groups, in particular at least three hydroxy groups. Generally, the number of hydroxy groups is not more than 10, more particularly not more than 8, or even not more than 6, in particular 2 or 3. The polyhydric alcohol has 2 to 15 carbon atoms. More particularly, the polyhydric alcohol has 3 to 10 carbon atoms. It is preferred that the polyhydric alcohol does not have N or S heteroatoms. More particularly, it is preferred that the polyhydric alcohol does not have non-carbon groups other than hydroxy groups. More particularly, the polyhydric alcohol is an aliphatic polyalkanol having only C, H, and O atoms. In a preferred embodiment of the present invention, the polyhydric alcohol has a relatively large number of hydroxy groups compared to its number of carbon atoms. For example, the ratio of the number of hydroxy groups to the number of carbon atoms ranges from 1:4 (i.e., 1 hydroxy group per 4 carbon atoms or per 8 carbon atoms for dialcohols) to 1:0.5 (i.e., 2 hydroxy groups per carbon atom). In particular, the ratio of the number of hydroxyl groups to the number of carbon atoms is in the range of 1:3 to 1:1, more in particular 1:2 to 1:1. A particularly preferred group of polyhydric alcohols is the group in which the ratio is in the range of 1:1.5 to 1:1. Compounds in which the ratio of hydroxyl groups to carbon atoms is 1:1 are considered to be particularly preferred.

[0035] Examples of suitable polyhydric alcohols include tri-alcohols selected from glycerol, sorbitol, xylitol and mannitol, and dialcohols selected from 1,2-propanediol, 1,3-propanediol and 1,2-ethanediol. The use of compounds selected from the group glycerol, sorbitol, xylitol and mannitol is preferred, with the use of glycerol being particularly preferred.

[0036] The preference for glycerol is based on the following: Firstly, glycerol has a melting point of 20° C., allowing easy processing, especially compared to xylitol, sorbitol and mannitol, which all have melting points well above 90° C. Furthermore, glycerol has been found to give high quality polymers, thus combining the use of readily available sources of material with good processing conditions and a high quality product. Mixtures of different types of alcohols can also be used.

[0037] However, it is preferred that the polyhydric alcohol consists of at least 50 mol%, preferably at least 70 mol%, more particularly at least 90 mol%, or even at least 95 mol% of glycerol, xylitol, sorbitol, or mannitol, in particular glycerol. In one embodiment, the polyhydric alcohol consists essentially of glycerol.

[0038] The use of glycerol, which is a by-product of the production of biodiesel by transesterification of glycerides with monoalcohols, is a particular embodiment of the present invention. Suitable monoalcohols include C1-C10 monoalcohols, particularly C1-C5 monoalcohols, more particularly C1-C3 monoalcohols, especially methanol. The glycerides are mono- and diesters of glycerol and fatty acids, the fatty acids generally having 10-18 carbon atoms. Suitable methods for producing biodiesel with the associated glycerol are known in the art.

[0039] The aliphatic polycarboxylic acid used in the present invention has at least two carboxylic acid groups, in particular at least three carboxylic acid groups. Generally, the number of carboxylic acid groups is not more than 10, more particularly not more than 8, or even not more than 6. The polycarboxylic acid has 3 to 15 carbon atoms. More particularly, the polycarboxylic acid has 3 to 10 carbon atoms. It is preferred that the polycarboxylic acid does not have any N or S heteroatoms. It is more particularly preferred that the polycarboxylic acid does not have any non-carbon groups other than the carboxylic acid groups. More particularly, the polycarboxylic acid is an aliphatic polycarboxylic acid having only C, H, and O atoms.

[0040] In one embodiment, dicarboxylic acid is used. When used, the dicarboxylic acid can be any dicarboxylic acid having two carboxylic acid groups and generally up to 15 carbon atoms. Examples of suitable dicarboxylic acids include itaconic acid, malic acid, succinic acid, glutaric acid, adipic acid and sebacic acid. Itaconic acid and succinic acid can be suitable.

[0041] In one embodiment, a tricarboxylic acid is used. The tricarboxylic acid, when used, can be any tricarboxylic acid having three carboxylic acid groups and generally up to 15 carbon atoms. Examples include citric acid, isocitric acid, aconitic acid (both cis and trans), and 3-carboxy-cis,cis-muconic acid. For both cost and availability reasons, the use of citric acid is considered to be preferred.

[0042] Where appropriate, the polycarboxylic acid may be provided wholly or partially in the form of an anhydride, for example anhydrous citric acid.

[0043] The use of tricarboxylic acids has been found to result in polyesters with attractive properties. Thus, in one embodiment, the polyacid comprises at least 10% by weight of tricarboxylic acid, whether or not it is combined with dicarboxylic acids, other tricarboxylic acids, and mixtures thereof. In one embodiment, the polyacid comprises at least 30% by weight, preferably at least 50% by weight, calculated based on the total amount of polyacid. In one embodiment, the amount of tricarboxylic acid is at least 70% by weight, more particularly at least 90% by weight, or even at least 95% by weight. In one embodiment, the polyacid consists essentially of tricarboxylic acid, where the term "essentially" means that other acids may be present in amounts that do not affect the properties of the material.

[0044] In another embodiment of the invention, the acid comprises at least 10% by weight, preferably at least 30% by weight, more preferably at least 50% by weight, of dicarboxylic acid, calculated on the total amount of acid. In one embodiment, the amount of dicarboxylic acid is at least 70% by weight.

[0045] In one embodiment, the acid comprises a combination of at least 10% by weight of tricarboxylic acid and at least 2% by weight of dicarboxylic acid, more particularly a combination of at least 10% by weight of tricarboxylic acid and at least 5% by weight of dicarboxylic acid, or at least 10% by weight of tricarboxylic acid and at least 10% by weight of dicarboxylic acid. In this embodiment, the weight ratio of the two acids can vary within a wide range depending on the desired properties of the material. In one embodiment, the dicarboxylic acid constitutes 2-90% by weight, particularly 5-90% by weight, more particularly 10-90% by weight of the total dicarboxylic and tricarboxylic acids depending on the properties of the material. It is noted that the preferred ranges of tricarboxylic acids specified above can also be applied to this embodiment. It has been found that the use of tricarboxylic acids, particularly citric acid, especially in combination with the use of trialcohols, such as glycerol, results in the formation of high quality composite materials.

[0046] Without wishing to be bound by theory, the inventors believe there are several reasons why the use of triacids, especially in combination with triols, produces high quality composite materials: First, the use of triacids, especially in combination with triols, produces highly crosslinked polymers, resulting in increased strength.

[0047] Furthermore, when a triacid, and preferably also a triol, is used, there is a high possibility that the acid or hydroxyl groups will physically or chemically interact with the active groups in the cellulose-based material. This will improve the bond between the cellulose-based material and the polymer, which is highly desirable when making composite materials. The degree of interaction can be controlled by selecting the amount of triacid and trialcohol, as well as by selecting the degree of polymerization.

[0048] The molar ratio of the polyhydric alcohol to the polyacid will be determined by the ratio of the number of reactive groups in the one or more alcohols used to the number of reactive groups in the one or more acids. In general, the ratio of the number of OH groups to the number of acid groups is 5:1 to 1:5. More particularly, the ratio can be 2:1 to 1:2, more particularly 1.5:1 to 1:1.5, more preferably 1.1:1 to 1:1.1. The theoretical molar ratio is 1:1.

[0049] The polymer is formed by combining the alcohol and the acid to form a liquid phase. Depending on the nature of the compounds, this can be done, for example, by heating a mixture of components to a temperature at which the acid will dissolve in the alcohol, particularly in glycerol. Depending on the nature of the compounds, this temperature can be, for example, in the range of 20-200°C, such as 40-200°C, such as 60-200°C, or 90-200°C. In one embodiment, the mixture can be heated and mixed at a temperature of 100-200°C, particularly 100-150°C, more particularly 100-140°C, for a period of 5 minutes to 2 hours, more particularly 10 minutes to 45 minutes.

[0050] Optionally, a suitable catalyst can be used for the preparation of the polyester. Suitable catalysts for the production of polyesters are known in the art. Preferred catalysts are those that do not contain heavy metals. Useful catalysts include hydrochloric acid, hydroiodic acid, hydrobromic acid, sulfuric acid (H 2 SO 4 ), nitric acid (HNO 3 ), chloric acid (HCIO 3 ), boric acid, perchloric acid (HCIO 4 Strong acids such as, but not limited to, acetic acid, trifluoroacetic acid, and trifluoromethanesulfonic acid. Catalysts such as Zn acetate and Mn acetate can also be used, but they may be less preferred.

[0051] Optionally, after polymerization and cooling of the reaction mixture, the mixture can be (partially) neutralized with a volatile base, such as ammonia or an organic amine, to stabilize the polyester solution. Preferred amines are low odor amines, such as, but not limited to, 2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl-1-propanol, 2-dimethylamino-2-methyl-1-propanol, etc.

[0052] In one embodiment, compounds are added to increase the interaction between the polymer and hydrophobic materials or to increase the water resistance of the final product. Suitable compounds include, for example, C5-C22 saturated or unsaturated fatty acids or their salts, C5-C22 saturated or unsaturated fatty alcohols, and dimeric and trimeric fatty acids or alcohols. For example, glycerol monostearate, triethyl citrate, and valeric acid have been successfully used in the present invention.

[0053] The compound for increasing hydrophobicity will generally be applied in an amount of 0.1 to 5% by weight, more particularly in an amount of 0.3 to 3% by weight, calculated on the amount of the polymer.

[0054] A layered material comprising a layer of a structural material provided with a composite surface layer comprising a structural material and a polyester derived from an aliphatic polyol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having 3 to 15 carbon atoms is generally prepared by contacting the surface of the structural material with a liquid medium comprising a polymer until the structural material is partially but not completely impregnated with the liquid medium, followed by a curing step.

[0055] In this application, the degree of polymerization of the monomer is expressed as a conversion value, which is the ratio of the percentage of functional groups that have reacted at a particular time to the maximum number of functional groups that can react.

[0056] The conversion value can be determined from the acid value of the reaction mixture compared to the theoretical acid value of the total monomers present. The conversion value can also be determined gravimetrically from the loss of water that occurs during the polymerization reaction.

[0057] Typically, the polymer will have a conversion value, determined using the acid value, in the range of 0.05 to 0.6, particularly 0.1 to 0.5, more particularly 0.2 to 0.5, when the polymer is applied onto a high porosity starting material.

[0058] After curing, the degree of conversion, as determined gravimetrically, will generally be at least 0.6, particularly at least 0.7, more particularly at least 0.8, and in some embodiments at least 0.9. The maximum degree of conversion is 1.0.

[0059] If it is intended to obtain an object having a layer of structural material and a composite surface layer comprising structural material and polyester, it is important that the production conditions are selected in such a way that the liquid medium does not penetrate the entire structural material, this effect being determined, inter alia, by the following parameters: the mode of application of the liquid medium, the amount of the liquid medium, the viscosity of the liquid medium, the absorption capacity of the structural material to be impregnated with the liquid medium, and the polymerization rate of the polymer in the absorbed medium.

[0060] The viscosity of the liquid medium is determined, for example, by the degree of conversion of the polyester in the medium, the temperature, and the optional presence of a solvent, such as water. The rate of polymerization of the polymer is determined, for example, by the presence of a catalyst, the temperature, and the efficiency of removing water (water is a by-product in the reaction). Given these parameters, it is within the skill of the art to select suitable contact conditions.

[0061] For example, a construction material can be contacted with an aqueous solution of the polyester at room temperature. It is also possible to contact a construction material with the polyester in liquid form at elevated temperature.

[0062] A liquid medium containing a polymer may be applied onto the high porosity starting material by methods known in the art, such as dipping, spraying, flowing, rolling, brushing, or cascading.

[0063] Immersion of the structural material in a liquid medium containing the polymer has been found to be advantageous as it results in a surface layer with a reproducible thickness, and the process is easy to apply by placing the layered material in a polymer bath for a controlled portion of time.

[0064] If it is desired to provide a surface layer on both sides of a panel, it is possible to apply a polymer layer on either side of the panel followed by a single curing step, however, it may be preferred to apply a first layer on one side of the panel, perform a curing step, and then apply a second layer on the other side of the panel followed by a second curing step.

[0065] After applying the polyester onto the structural material, the resulting impregnated material is subjected to a curing step to increase the degree of polymerization of the polyester. The key to the curing step is that the polyester is at a reaction temperature, for example at a product temperature of 80-250°C, especially 100-200°C. Curing can be carried out in heating devices known in the art, for example in ovens with oven temperatures of 80°C to 450°C. Various types of ovens can be used, including but not limited to belt ovens, tunnel ovens, convection ovens, microwave ovens, infrared ovens, induction ovens, hot air ovens, conventional baking ovens and combinations thereof. Curing can be carried out in a single step or in multiple steps, depending on the desired application. Curing times range from 5 seconds to 2 hours, depending on the application and the type and temperature of the oven used. It is within the skill of the art to select suitable curing conditions depending on the desired application and the desired properties. It may be preferred to carry out the curing step under an inert gas atmosphere, such as nitrogen, especially in the absence of oxygen. The use of an inert atmosphere allows the use of higher curing temperatures while limiting the occurrence of undesirable oxidation reactions.

[0066] If desired, the impregnated material may be subjected to a drying step before the curing step is carried out. The drying step, which is generally carried out at room temperature, e.g. 15°C, or at a temperature between 20°C and 100°C, is carried out to remove water from the composite. Depending on the amount of water in the composite, the thickness of the layer, and the temperature, it may be carried out for, e.g., 0.25 hours to 3 days.

[0067] In one embodiment, the application of a further surface layer is incorporated into the production of the layered material according to the invention. In this case, a surface layer is applied onto the panel after the application of the polymer but before the curing step, and the combined structure is presented to the curing step. This method allows the production of panels with attractive properties, such as an attractive surface structure and improved surface strength. The surface material can be a layer, such as a woven or nonwoven fabric. In this case, the surface layer is preferably porous so that it can absorb the polymer.

[0068] Surface materials also include other materials that alter the surface of the product, such as powders, flakes, or other materials.

[0069] The layered material according to the invention can be used in a manner known in the art as an insulating material for heat and sound. In view of the improved surface properties of the material according to the invention, a covering layer, such as gypsum or other plate material, can often be omitted. The new material can also find application in other situations where high porosity materials are used, such as filtration and hydroponic applications.

[0070] Some preferred modes of processing materials according to the present invention will be discussed below.

[0071] It has been found that the materials of the present invention have better mechanical properties and better self-supporting properties than the starting materials from which they are derived. This allows the materials to be processed in a novel manner. In one embodiment, the material according to the present invention, provided with a composite layer on the front, preferably on the front and back, in particular on the front, back and side, is provided as a self-supporting structure, optionally after being provided with a frame and / or a reinforcing structure, such as a beam, incorporated in the material.

[0072] It has been found that panels prepared according to the invention, especially the cellulose-based panels, can be easily provided with openings, for example to accommodate electrical sockets, cables, etc. Openings can be provided after application of the polymer, in which case the panel is easier to process due to the increased mechanical strength, or before application of the polymer, in which case the later application of the polymer ensures a smooth and strong surface for the openings. Before or after application of the polymer, the panels can also be provided with a structure that allows multiple panels to be bonded together, where the structure allows the panels to be connected to other structures, such as walls, frames, etc.

[0073] The improved mechanical strength of the panel, and in particular of its surface, allows fastening means, such as screws, to be provided directly on the panel.

[0074] If desired, the surface of the final layered material can be provided with a coating layer, for example in the form of a plaster, paint or wallpaper.

[0075] This disclosure also includes the following provisions:

[0076] 1. A layered high porosity material having a composite surface layer comprising a structural material and a polyester derived from an aliphatic polyol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having 3 to 15 carbon atoms, the surface layer being bonded to the high porosity layer of the structural material.

[0077] 2. A layered high porosity material according to clause 1 having a porosity of at least 0.5, in particular at least 0.6, more in particular at least 0.7, typically at most 0.98, in particular at most 0.95.

[0078] 3. A layered high porosity material according to any one of the above clauses, wherein the structural material is selected from ceramic wool, including ceramic wool, such as glass wool and stone wool, polymer-based materials, animal-derived materials, such as wool and down, and cellulose-based materials, and combinations thereof, with cellulose-based materials being preferred.

[0079] 4. A layered high porosity material according to any one of the preceding clauses, wherein the starting material has a porosity of at least 0.5, in particular at least 0.6, more in particular at least 0.7, even more in particular at least 0.8, and / or at most 0.995, in particular at most 0.98.

[0080] 5. A layered high porosity material according to any one of the preceding clauses, wherein the composite surface layer has a polymer content in the range of 50% to 98% by weight, more particularly in the range of 70% to 95% by weight, calculated based on the weight of the composite surface layer.

[0081] 6. A layered high porosity material according to any one of the preceding clauses, wherein the composite surface layer has a porosity in the range of 0.01 to 0.99, in particular in the range of 0.4 to 0.95.

[0082] 7. A layered high porosity material according to any one of the above clauses, wherein, in a cross-section of the layered material of the invention, one or more of the composite surface layers constitute at most 50% of the cross-section, and where a composite surface layer is provided on both sides of the layered material, the composite surface layer(s) in total preferably constitute 2 to 50%, in particular 5 to 40%, of the cross-section, and where a composite surface layer is provided on only one surface of the material, the composite surface layer preferably constitutes 2 to 30%, in particular 5 to 20%, of the cross-section.

[0083] 8. A layered high porosity material according to any one of the preceding clauses, wherein the aliphatic polyhydric alcohol is selected from the group of tri-alcohols selected from glycerol, sorbitol, xylitol and mannitol, and dialcohols selected from 1,2-propanediol, 1,3-propanediol and 1,2-ethanediol, in particular from the group of glycerol, sorbitol, xylitol and mannitol, more in particular glycerol.

[0084] 9. A layered high porosity material according to any one of the preceding clauses, wherein the aliphatic polycarboxylic acid is selected from the group of dicarboxylic acids selected from the group of itaconic acid, malic acid, succinic acid, glutaric acid, adipic acid and sebacic acid, and the group of tricarboxylic acids selected from the group of citric acid, isocitric acid, aconitic acid (both cis and trans) and 3-carboxy-cis,cis-muconic acid, in particular from the group of itaconic acid, succinic acid and citric acid, more in particular citric acid.

[0085] 10. A method for producing a layered high porosity material according to any one of the preceding clauses, comprising the steps of contacting a surface of the structural material with a liquid medium comprising a polymer until the structural material is partially but not completely impregnated with the liquid medium, and curing.

[0086] 11. The method according to clause 10, wherein the step of contacting the surface of the construction material with a liquid medium is carried out by immersion, spraying, flowing, rolling, brushing or cascading, in particular by immersion.

[0087] 12. The process according to clause 9 or 10, wherein the curing step is carried out at a product temperature of 80 to 250° C., in particular 100 to 200° C., preferably in an inert atmosphere.

[0088] 13. The method according to any one of clauses 10 to 12, wherein the application of a further surface layer is incorporated into the production of a layered material according to the invention by applying a further material onto the material after applying the polymer but before the curing step, and subjecting the combined structure to the curing step.

[0089] 14. Use of a substance according to any one of clauses 1 to 9 as a protective substance, as a filtering substance or in hydroponics.

[0090] 15. A method for processing a substance according to any one of clauses 1 to 9, wherein one or more of the following steps are carried out: providing the material according to any one of clauses 1 to 9, provided with a composite layer on the front, preferably on the front and on the back, in particular on the front, back and side surfaces, as a free-standing structure, optionally after being provided with a frame and / or reinforcing structures, e.g. beams, integrated into the material, A step in which openings are provided in a material according to any one of clauses 1 to 9, in particular in a material based on a cellulose-based material, before or after application of the polymer, a step in which a material according to any one of clauses 1 to 9, in particular a material based on a cellulose-based material, is provided with a structure allowing a plurality of panels to be bonded to one another, said structure allowing said panels to be bonded to other structures, A process in which a material according to any one of clauses 1 to 9, in particular a material based on a cellulose-based material, is provided with fixing means.

[0091] The invention will be elucidated by the following examples without being limited by or by them.

[0092] [Example 1] Cellulose-based panels - front and back A prepolymer mixture was prepared as follows: 1.0 kg of glycerol of >99% purity and 2.0 kg of citric acid (>99% purity) were placed in a stirred and heated reactor. 9 g of boric acid (0.5 m / m, >99% purity) was added as a catalyst. The mixture was heated to 135° C. for about 15 minutes and held at that temperature for 15 minutes. Tap water was then added to a polymer concentration of 20% by weight and the mixture was cooled to room temperature. The polymer has a conversion value of 0.4.

[0093] This process was repeated as necessary to obtain the desired amount of polymer solution.

[0094] A cellulose-based (recycled carboard / paper) protective panel (8 x 50 x 120 cm), commercially available from EverUse, with a porosity of 0.92 and a density of 90 grams per liter, was immersed on one surface (approximately 1 cm deep) in a layer of the polymer solution described above for 20 minutes at room temperature. This was done to allow the panel to absorb part of the polymer. After 20 minutes, the panel was removed from the polymer layer and turned over so that the wet side was facing up. When the panel was taken off the immersion (approximately 5 minutes), it was subjected to a curing process in a ventilated oven at 170°C (oven temperature) for 90 minutes. The panel was allowed to cool and absorb moisture for 1 day. A second coating layer was applied by immersing the panel with the uncoated side in a layer of the polymer solution as described above for 30 minutes. The panel was then removed from the polymer layer and turned over so that the wet layer was facing up. When the panel was taken off the immersion (about 5 minutes), it was subjected to a curing step in an oven at 170°C for 90 minutes, where both sides of the panel were coated and the absorbed moisture was cooled. When both sides were coated and cured, the panel was left at room temperature for 24 hours before being subjected to a second curing step (170°C for 60 minutes), and this process was repeated after another 24 hours.

[0095] Similar panels were prepared at higher cure temperatures and shorter cure times (190°C for 45 minutes) and shorter soak times (6-10 minutes).

[0096] The resulting product was a cellulose-based panel with composite surface layers on both sides, with an average thickness of 0.8 cm, a density of 0.55 kg / liter, and a porosity of 0.62. The overall density of the panel (composite and non-composite portions) was about 180 grams / liter. The overall porosity of the panel was 0.86, which is 93% of the porosity of the starting material.

[0097] No bubble formation was observed during panel manufacture. Heating the polymer itself under the conditions applied here typically results in the formation of bubbles. Apparently, all water was effectively removed during panel manufacture without producing bubbles.

[0098] Furthermore, the panels were odorless and had a hard surface. They could be easily processed, for example through sawing and sanding. The composite layer was also moisture permeable, which means that the good climate control characteristics of the cellulosic material were maintained.

[0099] An important property of the impregnated panel is that it is self-supporting, which is not the case with the starting material. Figure 1 shows a photograph of a panel according to the invention (top) and its starting material (bottom). As can be seen from the figure, the product according to the invention has a high bending stiffness, whereas the starting material does not.

[0100] It was found that the panel was a good surface for painting and that the surface layer was sufficiently rigid to allow the application of fastening means, such as screws. Figure 2 shows the strength of the surface of a panel according to the invention. Screws are inserted into the panel and can be used to lift the panel. If screws are similarly provided in the starting material, they will quickly pull away from the material when force is applied.

[0101] The panels had good humidity and water resistance. After 1 hour in boiling water, the composite surface layer remained intact.

[0102] Noise Absorption Characteristics The starting insulation panel is characterized by good noise absorbing properties. It is desirable to maintain these properties upon application of the composite layer. Therefore, a model experiment was set up to test the noise absorbing effect of the impregnated Everuse panels prepared above.

[0103] A box was made consisting of 6 small panels (25 x 25 cm). The front panel of the box was of the material to be tested. A sound generator was placed inside the box, facing the front panel. The sound source had a constant tone of 432 Hz. A dB meter was placed outside the box, at a distance of 30 cm from the sound generator. The dB meter was measured continuously for 1 minute, producing the average values ​​listed in the table below.

[0104] A "blank" measurement, where no front panel was used, produced a value of 91 dB. The uncoated panel gave a result of 82 dB. All other panels produced values ​​in the same range, indicating that the provision of the composite layer did not adversely affect the sound absorption properties of the panel.

[0105] [Table 1]

[0106] mechanical strength To determine the mechanical strength of the composite layer, a portion of the composite layer was separated from the panel. Pieces of composite layer having a length of 90 mm, a width of 19 mm, and a thickness of 8 mm were sawn. For comparison purposes, pieces with the same dimensions were prepared from non-impregnated plates. The tests were carried out on a Testrometic (M350-20CT) equipped for a three-point bending test with a gap of 80 mm. The compression speed was 1 mm / min. The breaking strength of the composite layer samples averaged 70 Newtons. The pieces of untreated panel could not hold the gap of 80 mm and collapsed under their own weight.

[0107] fire resistance To test the fire resistance of the composite layer, an ignition torch was held against the surface of the composite layer of the panel for 5 minutes, resulting in a blackening of the surface, but the surface layer not igniting.

[0108] [Example 2] Cellulose-based panels - advantages of side impregnation The panels can be six-sided impregnated to improve the overall strength of the panel and minimize the need for additional mechanical support frames for the panel, therefore the top and bottom of the panel as well as the edges of the panel are impregnated for testing purposes of the effect on the panel strength.

[0109] A panel was produced as follows using the starting materials and polymer solution described in Example 1. The front side of the panel was placed in the polymer solution for 20 minutes to allow absorption of the polymer. The panel was heated at 170°C for 1.5 hours in a ventilated oven. The four sides and the back side of the panel were then coated by placing each side in turn in the polymer solution for 20 minutes. The panel was then heated again to 170°C for 1 hour. The thickness of all composite layers was approximately 8 mm. The presence of composite layers on all sides of the panel resulted in a panel with very high stiffness in all directions. Multiple panels with different sizes were produced.

[0110] To investigate the effect of impregnation of the panel size on the compressive strength of the panels, panels were prepared as described above, except that only the sides of the panels were impregnated, while the top and bottom were not impregnated. Compressive properties were tested using a universal testing machine (UTM) (Testrometic, M350-20CT) equipped with a compression plate. The panels with four sides impregnated showed an average compressive strength of 642N. The panels that were not impregnated showed a compressive strength of virtually zero. This indicates that impregnation of the sides of the panels significantly improves the compressive strength of the panels.

[0111] [Example 3] Further Use of Panels Panels according to the invention can be provided with internal strengthening or connecting means, such as beams or frames, to provide a ready-to-use self-supporting structure. Figure 3 shows an example where a beam is incorporated between two panels. Figure 4 shows the self-supporting structure of a set of panels within a frame.

[0112] [Example 4] Other substances High porosity mats of several other materials were subjected to the process according to the invention. The starting materials were two stone wool materials of different densities, glass wool, hemp mat, and flexible open-cell polyurethane foam. The properties of the starting materials are shown in the table below.

[0113] In these examples, the polymer composition was used as described in Example 1, except that 4.5 grams of glycerol monostearate was added to the polymer composition to improve the adhesion of the polymer to materials with slightly hydrophobic characteristics.

[0114] The mat was impregnated on one side followed by a single curing step according to the procedure described in Example 1. The samples were impregnated for 20 minutes and cured at 170° C. for 3 hours.

[0115] [Table 2]

[0116] After impregnation and curing of the polyurethane mat, a good homogeneous 6 mm thick composite layer was obtained, which was hard, strong and had a surface structure similar to that of the non-impregnated mat, and was very easy to process, for example through sawing and grinding. The composite layer was also very suitable for providing screws.

[0117] The impregnated stone wool and glass wool samples also had good homogeneity, were odorless, and had a relatively thin and hard composite layer. The hemp mat had a thicker (6 mm) composite layer that was continuous but less homogeneous than the layers in the other materials, related to the rather non-uniform structure of the impregnated hemp mat.

[0118] [Example 5] Incorporation of a coating layer In one embodiment of the present invention, a porous surface layer is applied to the top of the panel before or during impregnation. This allows the production of a product with an attractive surface structure that may not require further final finishing. In this example, Example 1 was repeated, except that after impregnation but before curing, a linen woven cloth was applied on the front side. A dry cloth was applied on the wet panel to absorb the polymer from the panel. The front side of the final product had excellent visual and tactile properties. In addition, the presence of the cloth may further increase the strength of the panel. Figure 5 shows the panel obtained according to this example.

Claims

1. 1. A layered high porosity material having a composite surface layer comprising a structural material and a polyester derived from an aliphatic polyol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having 3 to 15 carbon atoms, the surface layer being bonded to a high porosity layer of a structural material, the composite surface layer having a polymer content in the range of 50% to 98% by weight, calculated based on the weight of the composite surface layer, one or more of the composite surface layers making up at most 50% of the cross section of the layered high porosity material, the layered high porosity material having a porosity of at least 0.5, calculated from the density of the layered high porosity material and the densities of the materials constituting the layered high porosity material, and the composite surface layer having a porosity in the range of 0.4 to 0.95, calculated from the density of the composite surface layer and the densities of the materials constituting the composite surface layer.

2. 10. The layered high porosity material of claim 1 having a porosity of at least 0.6 and at most 0.

98.

3. 3. The layered high porosity material of claim 1 or 2, wherein the structural material is selected from ceramic wool, including glass wool and stone wool, polymer-based materials, animal-derived materials, and cellulose-based materials, and combinations thereof.

4. 4. The layered high porosity material of claim 1, wherein the composite surface layer has a polymer content in the range of 70% to 95% by weight, calculated based on the weight of the composite surface layer.

5. A layered high porosity material according to any one of claims 1 to 4, wherein the composite surface layer has a porosity in the range of 0.01 to 0.

99.

6. 6. A layered high porosity material according to any one of claims 1 to 5, wherein, when viewed in cross section, the composite surface layer comprises, in total, 2 to 50% of the cross section when a composite surface layer is provided on both sides of the layered high porosity material, and when a composite surface layer is provided on only one surface of the material, the composite surface layer comprises 2 to 30% of the cross section.

7. 7. The layered high porosity material according to any one of claims 1 to 6, wherein the aliphatic polyol is selected from the group consisting of glycerol, sorbitol, xylitol, mannitol, 1,2-propanediol, 1,3-propanediol and 1,2-ethanediol.

8. 8. The layered high porosity material of any one of claims 1 to 7, wherein the aliphatic polycarboxylic acid is selected from the group of dicarboxylic acids selected from the group of itaconic acid, malic acid, succinic acid, glutaric acid, adipic acid and sebacic acid, and tricarboxylic acids selected from the group of citric acid, isocitric acid, aconitic acid (both cis and trans), and 3-carboxy-cis,cis-muconic acid.

9. 9. A method for producing a layered high porosity material according to any one of claims 1 to 8, comprising the steps of contacting a surface of the structural material with a liquid medium comprising a polymer until the structural material is partially but not completely impregnated with the liquid medium, and curing.

10. 10. The method of claim 9, wherein the step of contacting the surface of the construction material with a liquid medium is performed by dipping, spraying, flowing, rolling, brushing, or cascading.

11. The method according to claim 9 or 10, wherein the curing step is carried out at a product temperature of from 80 to 250°C.

12. 12. A method according to any one of claims 9 to 11, wherein the application of a further surface layer is incorporated into the production of the layered high porosity material by applying a further material onto the material after applying the polymer but prior to the curing step, and subjecting the combined structure to said curing step.

13. Use of a material according to any one of claims 1 to 8 as a barrier material, as a filtering material or in hydroponics.

14. A method for processing a material according to any one of claims 1 to 8, comprising carrying out one or more of the following steps: providing a material according to any one of claims 1 to 8 as a free-standing structure, the material having a composite layer on the front side; A step in which an opening is provided in a material according to any one of claims 1 to 8, - providing a material according to any one of claims 1 to 8 with a structure enabling a plurality of panels to be joined together, said structure enabling the panels to be joined to other structures; A process in which a material according to any one of claims 1 to 8 is provided with fixing means.

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