Method for manufacturing non-flat articles

Abstract

The present invention relates to a method for producing a non-planar article, the method comprising the steps of: providing a structure comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization greater than 0 and less than 1.0, or a precursor monomer of such a polymer, wherein the structure has a void fraction of 0.3 to 0.98 and a water content of less than 40% by weight; and, if the degree of polymerization is less than 0.5, polymerizing the structure to a degree of polymerization of 0.5 to 1, pressing if necessary to reduce the void fraction; and forming the structure into a non-planar article by applying a force in a defined sequence at an internal temperature above the glass transition temperature (Tg) of the polymer to form a non-planar article having a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. The present invention also relates to non-planar articles obtainable by the method and to structures suitable for use in the method.

Description

[Technical Field] 【0001】 The present invention relates to a method for producing articles from fibrous materials, such as bio-based fibrous materials, and polymer-containing resins. The articles thus obtained are remarkably strong and scratch-resistant, and can be formed into non-flat shapes. The present invention also relates to articles that can be obtained by this method, and structures for use in this method. [Background technology] 【0002】 Various methods for manufacturing articles from bio-based materials are known in this technology. These articles are desirable for sustainability reasons. 【0003】 For example, International Publication No. 2012 / 140237 describes a method for producing a composite material comprising 10 to 98% by weight of a bio-based particulate or fibrous filler and at least 2% by weight of polyester, wherein the method comprises combining the filler and the polyester (or its precursor) and subjecting the combined material to a curing step. 【0004】 International Publication No. 2012 / 140238 describes a method for manufacturing laminates. A carrier is coated with a layer of polyester. The composite is then cured to give a laminate. By using this method, stacks of wood can be bonded together. 【0005】 In the market, there is a growing interest in articles derived from renewable resources, particularly bio-based resources, especially in the fields of furniture, transportation (e.g., the automotive industry), and construction. Of course, in addition to being derivable from renewable resources, the articles must also meet other requirements. They should combine an attractive natural appearance and feel, as demonstrated, for example, by meeting the requirements of applicable European standards, with good strength and durability characteristics, such as good scratch resistance and good resistance to repeated application of force. 【0006】 In addition, it must be possible to manufacture articles having substantially any shape, including, for example, complex shapes. These include furniture (e.g., chairs, (bar) stools, and sofas), non-flat articles for construction, and non-flat articles for the transportation (e.g., automotive) industry (e.g., panels in automotive doors). Conventionally used natural materials, such as wood, generally do not have the desired formability. 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0007】 The present invention relates to a method for solving these problems. This enables the manufacture of articles having a structurally complex (e.g., non-flat) shape, which, as described above, have a good (natural) appearance and feel, high strength, and good durability characteristics, and which can be obtained from renewable resources. This method is disclosed herein. Means for Solving the Problems 【0008】 The present invention is a method for manufacturing a non-flat article, the method comprising Prepare a structure comprising a fibrous material and a resin containing a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization greater than 0 and up to 1.0, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 40% by weight, and subject the structure to the following steps If the degree of polymerization is less than 0.5, polymerize it to a degree of polymerization of 0.5 to 1, Press to reduce the void ratio, and Apply a force at an internal temperature above the T g of the polymer to form the structure into a non-flat article, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight, subject to including the steps of wherein polymerizing (if performed), reducing the void ratio, and forming are performed simultaneously, or polymerizing (if performed) and reducing the void ratio are performed simultaneously, followed by forming, or polymerizing (if performed) and reducing the void ratio are performed consecutively in any order, followed by forming, or after polymerizing (if performed), reducing the void ratio and forming are performed, wherein the forming is performed simultaneously with or subsequent to reducing the void ratio relating to the above method. 【0009】 Remarkably, this method enables the manufacture of non-planar articles of almost any shape. The composition of the structure, i.e., the starting material in the method according to the present invention, has been found to be particularly important. Specifically, the use of fibrous materials with a high void ratio, especially nonwoven fibrous materials, has been found to be advantageous because the fibers in such materials have some degree of freedom to move relative to one another. As a result, the fibrous material can take on almost any shape, which is stabilized by the polymer in the resin. In addition, fibrous materials with a high void ratio are easier to impregnate with resin than fibrous materials with a low void ratio. This results in better adhesion of the fibers and, therefore, a stronger final product. Moreover, advantageously, if the water content of the structure is less than 20% by weight and the degree of polymerization of the polymer is at least 0.5, resin waste is reduced and the time required to form the structure is shortened. Thus, by selecting the degree of polymerization and water content as defined herein, unnecessary energy consumption and environmental impact from the disposal of starting materials are reduced. This also allows the structure to be shipped as a ready-to-use starting material for manufacturing non-flat articles, thereby facilitating the manufacture of non-flat articles with less environmental impact. (Mode for carrying out the invention) 【0010】 The method is disclosed in more detail below. Specific advantages of the method and specific embodiments thereof will become apparent from the further specification below. 【0011】 Textile materials The starting material in the method described herein is a structure comprising a fibrous material and a resin. 【0012】 The structure used in the method of the present invention comprises one or more layers of the fibrous material. In one embodiment, the structure comprises a single layer of the fibrous material. In another embodiment, the structure comprises two or more layers of the fibrous material, for example, 2 to 10 layers, preferably 3 to 6 layers. The layers of the fibrous material may be woven or nonwoven layers. Preferably, the layers of the fibrous material may be nonwoven layers, because they are easier to form. If the layers of the fibrous material are woven layers, it may be desirable to use two or more layers of the fibrous material. In the context of this specification, the term “fiber” means monofilament, multifilament yarn, threads, tape, strip, and other elongated objects having a regular or irregular cross-section and a length substantially longer than its width and thickness. 【0013】 The presence of fibrous material within the structure is important because it provides the structure with formability, strength, and volume. It will be understood that the fibrous material used in the method of the present invention is flexible and can be subjected to high pressure without adversely affecting its fibrous properties. In addition, the fibrous material can also impart specific properties to the final product, such as a desired appearance and feel or a specific texture. 【0014】 The structure has good formability, at least partially, because the fibrous material used therein has a defined void ratio. The fibrous material (without resin) generally has a void ratio of at least 0.4, particularly at least 0.5, more specifically at least 0.6, even more specifically at least 0.7, and even more specifically at least 0.8. As a general upper limit, values ​​of 0.98 or less may be mentioned. The void ratio reflects the volume of voids in the material over the total volume of the material (which may be filled with gas, e.g., air). Thus, the void ratio of the fibrous material can be calculated from the density of the fibrous material itself and the density of the material constituting the fibrous material (i.e., the density of hemp if the fibrous material is a hemp layer). 【0015】 In nonwoven fiber materials, the fiber material generally has a fiber length of 0.5 to 10 cm, determined along its longest axis. Preferably, the fiber material has a fiber length of 1 to 10 cm. More preferably, the fiber material has a fiber length of 2 to 7 cm. In the fiber material, the fiber length is generally equivalent to the length and width of the material. For example, if a woven fiber material is used to manufacture a seat for a chair, the fibers in one direction may have a length corresponding to the length of the seat, while the fibers in the other direction may have a length corresponding to the width of the seat. 【0016】 The fibrous material may include plant-derived fibers, preferably cellulosic and / or lignocellulosic fibers. The fibrous material may also consist of essentially plant-derived fibers. Fibers based on plant-derived fibers include, for example, flax, hemp, kenaf, jute, ramie, sisal, palm, cotton, etc. The fibrous material may also contain animal-derived fibers. These animal-derived fibers may be wool, hair, silk, or feathers (e.g., chicken feathers). Other parts of the organs may also be used. 【0017】 The fibrous material may include synthetic fibers. Suitable examples of synthetic fibers are those derived from viscose, glass, polyester, carbon, aramid, nylon, acrylic, polyolefin, etc. The fibrous material may also be a mixture of fibers of different origins, for example, a mixture of plant-derived fibers and synthetic fibers. 【0018】 One or more layers of fibrous material are generally in the form of sheets (e.g., fiber mats). The fibers of these sheets are oriented in a random (e.g., nonwoven sheet) or non-random manner. In the context of this specification, "oriented in a non-random manner" means all structures in which the fibers are oriented toward each other in an essentially regular manner. Examples of sheets containing non-randomly oriented fibers include woven layers, knitted layers, layers in which the fibers are oriented parallel to each other, and any other layers in which the fibers are connected to each other in a repeating pattern. 【0019】 The fiber orientation of the layer of the fibrous material can, for example, affect the strength of the final product (i.e., the article that can be obtained by the method according to the present invention). Therefore, it may be preferable to orient the fibers in a manner that maximizes the strength of the article. In some embodiments, at least 50% of the fibers are oriented parallel, preferably at least 60% of the fibers are oriented parallel, and more preferably at least 70% of the fibers are oriented parallel. For example, if the article is a seat for a chair, the fibers may be oriented from the front of the seat to the top of the backrest. In other cases, more anisotropy or bidirectional resistance may be required. The fibers may then be oriented in two or more directions. Combinations of different layer structures may also be used. 【0020】 resin The structure used in the method of the present invention also comprises a resin comprising an aliphatic polyalcohol having 2 to 15 carbon atoms and a polymer derived from an aliphatic polycarboxylic acid having 3 to 15 carbon atoms. 【0021】 Aliphatic polyalcohols do not contain aromatic moieties, nitrogen atoms, or sulfur atoms. In some embodiments, aliphatic polyalcohols essentially consist of carbon atoms, oxygen atoms, and hydrogen atoms. Aliphatic polyalcohols contain at least two hydroxyl groups, preferably at least three hydroxyl groups. Generally, the number of hydroxyl groups is 10 or less, preferably 8 or less, and more preferably 6 or less. 【0022】 Aliphatic polyalcohols have 2 to 15 carbon atoms, preferably 3 to 10 carbon atoms. Examples of suitable aliphatic polyalcohols are 1,2-propanediol, 1,3-propanediol, 1,2-ethanediol, glycerol, sorbitol, xylitol, and mannitol. Glycerol, sorbitol, xylitol, and mannitol are preferred examples of suitable aliphatic polyalcohols. Glycerol is the most preferred example of a suitable aliphatic polyalcohol. This is because glycerol has a melting point of 20°C, making it easy to process (compared to xylitol, sorbitol, and mannitol, which all have melting points above 90°C, for example). Moreover, glycerol is readily available and results in polymers with desirable properties. Therefore, in some embodiments, the aliphatic polyalcohol consists essentially of glycerol. As used herein, "essentially consists of..." means that other components (other aliphatic polyalcohols, as used herein) may be present in amounts that do not affect the properties of the material. 【0023】 Mixtures of different aliphatic polyalcohols may also be used. The aliphatic polyalcohol may contain at least 50 mol%, preferably at least 70 mol%, preferably at least 90 mol%, of glycerol, sorbitol, xylitol, or mannitol. Preferably, the remainder is an aliphatic polyalcohol having 3 to 10 carbon atoms. The polyhydric alcohol preferably contains at least 70 mol%, preferably at least 90 mol%, more preferably at least 95 mol%, of glycerol. 【0024】 In some embodiments, the aliphatic polyalcohol has a ratio of hydroxyl groups to carbon atoms of 1:4 (i.e., one hydroxyl group per four carbon atoms) to 1:1 (i.e., one hydroxyl group per carbon atom). The ratio of hydroxyl groups to carbon atoms is preferably 1:3 to 1:1, more preferably 1:2 to 1:1, and even more preferably 1:1.5 to 1:1. Compounds in which the ratio of hydroxyl groups to carbon atoms is 1:1 are considered particularly preferred. 【0025】 Aliphatic polycarboxylic acids have 3 to 15 carbon atoms, preferably 3 to 10 carbon atoms. Aliphatic polycarboxylic acids do not contain aromatic moieties or nitrogen or sulfur atoms. In some embodiments, aliphatic polycarboxylic acids consist of carbon atoms, oxygen atoms, and hydrogen atoms. Aliphatic polycarboxylic acids contain at least two carboxylic acid groups, preferably three carboxylic acid groups. Generally, the number of carboxylic acid groups is 10 or less, preferably 8 or less, and more preferably 6 or less. 【0026】 In particular, the aliphatic polycarboxylic acid contains at least 10% by weight of tricarboxylic acid, calculated relative to the total amount of the aliphatic polycarboxylic acid. The aliphatic polycarboxylic acid may also contain at least 30% by weight, preferably at least 50% by weight, more preferably at least 70% by weight, even more preferably at least 90% by weight, and most preferably 95% by weight of tricarboxylic acid, calculated relative to the total amount of the acid. In some embodiments, the aliphatic polycarboxylic acid consists essentially of tricarboxylic acid, and preferably essentially of citric acid. 【0027】 A 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 reasons of both cost and availability, the use of citric acid is considered preferable. 【0028】 A dicarboxylic acid, when used, can be any dicarboxylic acid having two carboxylic acid groups, generally up to 15 carbon atoms. Examples of preferred dicarboxylic acids include itaconic acid, malic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, and oxalic acid. Itaconic acid and succinic acid may be preferred. In one embodiment, a tricarboxylic acid is used. 【0029】 The aliphatic polycarboxylic acid may be a mixture of acids, for example, a mixture of one or more tricarboxylic acids and one or more dicarboxylic acids. In some embodiments, the aliphatic polycarboxylic acid comprises a compound of at least 2% by weight, preferably at least 5% by weight, more preferably at least 10% by weight, of a dicarboxylic acid and at least 10% by weight, preferably at least 30% by weight, more preferably at least 70% by weight, even more preferably at least 90% by weight, and most preferably at least 95% by weight, of a tricarboxylic acid, calculated based on the total amount of the aliphatic polycarboxylic acid. 【0030】 The aliphatic polyalcohols and aliphatic polycarboxylic acids used in the method according to the present invention can react to form polymers. 【0031】 The polymer can be obtained by combining a polyalcohol and a polycarboxylic acid (and optionally, a polymer derived from the polyalcohol and polycarboxylic acid) to form a liquid phase, and, if necessary, by curing the resulting liquid phase. Depending on the properties of the compound, this can be done, for example, by heating a mixture of components to a temperature at which an acid will dissolve in an alcohol, particularly glycerol. Depending on the properties of the compound, the temperature can be, for example, in the range of 20°C to 200°C, preferably 40°C to 200°C, more preferably 60°C to 200°C, and most preferably 90°C to 200°C. In some embodiments, the compounds may be heated and mixed for 5 minutes to 12 hours, preferably 10 minutes to 6 hours, at a temperature in the range of 100°C to 200°C, preferably 100°C to 150°C, more preferably 100°C to 140°C. The polymer is preferably obtained by curing at a temperature of 140°C or lower. 【0032】 Optionally, a suitable catalyst can be used for the preparation of the polymer. Suitable catalysts for polymer production are known in the art. Preferred catalysts are those that do not contain heavy metals. Useful catalysts include, but are not limited to, strong acids such as hydrochloric acid, hydroiodic acid and hydrobromic acid, sulfuric acid (H2SO4), nitric acid (HNO3), chloric acid (HClO3), boric acid, perchloric acid (HClO4), trifluoroacetic acid, p-toluenesulfonic acid, and trifluoromethanesulfonic acid. Boric acid may be preferred. Catalysts such as Zn-acetate and Mn-acetate can also be used, but may be less preferred. 【0033】 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 polymer solution. Preferred organic amines are, but are not limited to, low-odor amines such as 2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl-1-propanol, and 2-dimethylamino-2-methyl-1-propanol. 【0034】 Depending on the reaction conditions, the polymer derived from the aliphatic polyalcohol and aliphatic polycarboxylic acid may have a degree of polymerization of 0.10 to 0.60, preferably 0.20 to 0.60, and more preferably 0.30 to 0.60, if newly obtained. In this specification, “degree of polymerization” is the ratio of the portion of functional groups that have reacted at a given time to the maximum number of functional groups that can react. For example, if the monomers have not reacted, the degree of polymerization is 0. The degree of polymerization can be determined by comparing the acid value of the reaction mixture with the theoretical acid value of the sum of the monomers present. This method may be preferred if visual inspection suggests that the degree of polymerization is ≤0.5. Alternatively, the degree of polymerization can be determined using gravimetric analysis (from water loss during the polymerization reaction). This method may be preferred if visual inspection suggests that the degree of polymerization is >0.5. 【0035】 If necessary, the resin can be diluted to control its viscosity. For example, the resin can be diluted with water. This may be done to facilitate the impregnation of one or more layers of the fibrous material with the resin. In some embodiments, the viscosity of the resin is 0.55-10 (at room temperature). -3 The viscosity may be Pa·s to 50 Pa·s, preferably 0.05 Pa·s to 2.5 Pa·s, more preferably 0.1 Pa·s to 0.15 Pa·s. In other embodiments, the viscosity of the resin may be 1 Pa·s or less (at room temperature), preferably 0.5 Pa·s or less, more preferably 0.1 Pa·s or less, and even more preferably 0.01 Pa·s or less. The viscosity can be measured using any method well known in the art. 【0036】 General method structure A fibrous material as defined herein and a resin containing polymers derived from aliphatic polyalcohols and aliphatic polycarboxylic acids as defined herein can be combined to prepare a structure as defined below and in the claims herein. 【0037】 The fibrous material may be present in the structure in an amount of at least 10% by weight relative to the total weight of the starting materials used, without containing water. The fibrous material may be present in the structure in an amount of up to 95% by weight relative to the total weight of the starting materials used, without containing water. If the amount of fibrous material is too small, it may be difficult to successfully form an article from the structure because the structure may be relatively rigid, making it more difficult to form. In addition, the strength of the resulting non-planar article may not be desirable. If the amount of fibrous material is too large, this will affect the strength of the article that can be obtained by this method, because the fibers may not adhere properly. This will affect the properties of the non-planar article, such as (flexural) strength, appearance and feel, and overall appearance. In some embodiments, the amount of fibrous material is 20% to 90% by weight, preferably 30% to 85% by weight, more preferably 35% to 80% by weight, more preferably 40% to 80% by weight, and more preferably 50% to 80% by weight. 【0038】 By cutting the fibrous material into a predetermined shape, waste of the starting material can be reduced and the formation process can be facilitated. Cut-offs from one or more layers of the fibrous material can be reused to create new layers of the fibrous material. For example, when manufacturing a seat for a chair, it may be desirable to cut one or more layers of the fibrous material into a shape substantially like the hemp mat illustrated in Figure 1. 【0039】 The fibrous material in the structure is at least partially supplied with a resin as defined herein. Preferably, the resin is supplied to at least 80%, more preferably at least 90%, and most preferably at least 95% of the fibers of the fibrous material. The more fibers of the fibrous structure are supplied with resin, the easier it will be to manufacture non-planar articles from the structure. Those skilled in the art will understand that the application of the resin can be carried out using methods well known in the art, such as spraying, dipping, roll coating, vacuum injection, etc. For example, the resin may be (roll) coated or sprayed onto one or more sides of the fibrous material. In some embodiments, the resin is supplied to one or more layers of the fibrous material, respectively. 【0040】 Providing resin can mean providing resin to the entire fiber surface, or it can mean providing resin to only a portion of the fiber surface. In the forming process described below, the fibers within the structure are pressed together, thereby resulting in the redistribution of the resin. If only a portion of the fiber surface is covered with resin before the compression process, this redistribution may result in resin being provided to a larger portion of the fiber surface. In the final article, it is preferable that the resin be provided to essentially all fiber surfaces, since the interaction between the fibers and the resin is at least partially involved in obtaining the attractive properties of the article in question. The application of excess resin may be attractive from a processing standpoint to ensure effective coating of the fibers. Excess resin can be removed at any stage of the process using conventional methods, such as the application of pressure. 【0041】 The resin may, after being applied to the fibrous material, contain a polymer as defined herein having a degree of polymerization of greater than 0 to 1, preferably 0.01 to 1, more preferably 0.1 to 0.9, and most preferably 0.4 to 0.8. It is also possible for the polymer to have a degree of polymerization of 0, i.e., to contain monomers. Generally, it is preferable that the resin contains a polymer having the degree of polymerization specified above. If the degree of polymerization is too high immediately before formation, particularly if the polymer impairs the movement of fibers within the structure, it may be difficult to successfully form the structure into an article. If the degree of polymerization is low (too low), a pre-curing step may be ensured. 【0042】 The resin content of the structure may be 5% to 90% by weight, preferably 10% to 70% by weight, calculated relative to the total weight of the fiber material and the weight of the polymer. Preferably, the resin content is 20% to 55% by weight. More preferably, the resin content is 30% to 50% by weight. The resin content as defined herein is desirable because the polymer is expected to bond to the fibers of the fiber material. This results in structural stability after the formation process. 【0043】 The structure has a water content of 0.1% to 60% by weight, calculated relative to the total weight of the structure, immediately before formation. In some embodiments, the water content of the structure is 0.1% to 25% by weight, preferably 0.1% to 20% by weight, and more preferably 0.1% to 10% by weight. A low water content of the structure can be advantageous because it reduces the time required to form the structure and, in some cases, reduces the waste of the resin due to leakage from the structure. A low water content also helps to avoid steam explosions that can occur during formation, which can damage the fibers and create safety hazards during formation. The water content is defined as the amount of water in the structure divided by the total mass of the structure. 【0044】 If the water content of the structure is too high, it may be subjected to a drying process to remove excess water. The drying process may be carried out under conditions suitable for removing water. During the drying process, little or no polymerization of the resin occurs. This is because, when a drying process is necessary, the water content is high and the drying temperature is lower than the temperature at which significant polymerization occurs. The drying may be carried out at a temperature below 60°C, preferably between 10°C and 60°C, more preferably between 10°C and 50°C, even more preferably between 20°C and 50°C, and most preferably between 30°C and 50°C. The drying time is preferably 48 hours or less, more preferably 24 hours or less. In some embodiments, the drying time is much shorter, preferably up to 8 hours, more preferably up to 4 hours, even more preferably up to 2 hours, and most preferably up to 1 hour. A minimum drying time of 5 minutes may be mentioned. Reduced pressure may be applied to accelerate drying. The reduced pressure may be 0.9 bar or less, preferably 0.5 bar or less, and more preferably 0.1 bar or less. The drying can reduce the moisture content to less than 20% by weight, preferably less than 10% by weight, more preferably less than 5% by weight, and most preferably less than 2% by weight, relative to the total weight of the structure. 【0045】 Additionally or alternatively, depending on the degree of polymerization, the (dried) structure may be subjected to a pre-curing step before forming the structure. During the pre-curing, polymerization of the resin may occur and (reaction) water may be removed. The pre-curing may be carried out at a temperature of at least 60°C. For example, the pre-curing may be carried out at a temperature of 60°C to 140°C, preferably 60°C to 120°C, more preferably 80°C to 120°C. If a drying step is applied, the pre-curing may result in a degree of polymerization of at least 0.6, preferably at least 0.7. If drying is not applied, the pre-curing may reduce the water content to less than 35% by weight, preferably less than 20% by weight, more preferably less than 10% by weight, even more preferably less than 5% by weight, and most preferably less than 2% by weight, calculated relative to the total weight of the structure. The pre-curing may be carried out for at least 5 minutes, preferably at least 10 minutes, more preferably at least 1 hour. A pre-curing time of up to 24 hours may be mentioned. Generally, this pre-curing is carried out in an oven. Since moisture is removed during drying, and therefore high humidity is counterproductive, it is advantageous to carefully control the humidity inside the oven. Accordingly, during pre-curing, the humidity inside the oven may be less than 50%, preferably less than 40%. The lower the humidity, the faster the drying process. 【0046】 The structure has a void fraction of at least 0.3, more particularly at least 0.4, more particularly at least 0.5, even more particularly at least 0.6, and even more particularly at least 0.7. As a general upper limit, values ​​of 0.98 or less may be mentioned. As stated above, the void fraction can be calculated from the density of the material, as it reflects the volume of voids in the material over the total volume of the material (which may be filled with gas, e.g., air). For materials containing two or more components, the theoretical density of the material can be determined by multiplying the density of each component by the weight fraction of the component and adding the resulting values ​​(see Lever rule). 【0047】 The present invention also relates to a structure suitable for use in a method according to the present invention, the structure comprising a fibrous material impregnated with a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid, wherein the structure has a void ratio of 0.3 to 0.98, the polymer has a degree of polymerization of 0.5 to 0.8, and the structure has a water content of less than 20% by weight. Preferably, the structure has a water content of less than 10% by weight. Other preferred embodiments have been described above and will be apparent from that description. 【0048】 Reducing and forming the void ratio Next, the structure is subjected to pressing to reduce the void ratio and to form the structure into a non-flat article, whether or not it has undergone a drying and / or pre-curing process. The pressing and forming processes may be combined, but it is also possible to perform the pressing process first and then the forming process, as will be described in more detail below. 【0049】 The pressing process is carried out by applying force to the structure. The applied pressure is 2 to 40 bar (= kg / 1 cm of structure). 2 The pressure may be preferably 5 to 30 bar, more preferably 10 to 20 bar. The duration of the pressing step may be in the range of 15 seconds to 30 minutes if simultaneous forming is not performed. If simultaneous forming is intended, the time may be longer, as described below. The pressing may be performed using thickness control to determine the thickness of the article obtained by the method. Preferably, the thickness of the article obtained by the method is in the range of 0.5 mm to 10 cm, preferably 3 mm to 5 cm, more preferably 4 mm to 2 cm. Specifically, if the article is a furniture part, the thickness of the article obtained by the method may be in the range of 5 mm to 15 mm, preferably 7 mm to 12 mm. 【0050】 The temperature applied in the pressing process depends on whether the sole purpose is to reduce the void ratio or to form voids. If the sole purpose is to reduce the void ratio, the temperature is, for example, in the range of 10 to 50°C. If simultaneous formation is the purpose, the temperature is higher, as described below. 【0051】 The structure may be pre-formed, for example, by fitting it into a mold. It may be advantageous to line the mold with a Teflon coating, at least partially. This helps prevent the structure from adhering to the mold. 【0052】 The structure is formed (i.e., shaped) by the application of force. The forming process results in an article of remarkable strength, as well as increased surface uniformity and scratch resistance. The forming process is generally carried out in or on a mold, where the mold is defined as a shape capable of supporting the structure before the forming process, thereby ensuring that an article with the desired shape is obtained after the forming process. 【0053】 The force is generally applied by pressing the structure inside or on a mold, preferably a mold coated with Teflon material. The pressure applied is 2 to 40 bar (= kg / structure 1 cm) 2The pressure may be preferably 5 to 30 bar, more preferably 10 to 20 bar. For example, the pressure may be applied for a total duration of at least 5 seconds. The longer the duration of the formation, the greater the stability of the article. It will be understood that forming for a very long period of time is not commercially attractive. Therefore, a maximum duration of 24 hours, preferably 1 hour, more preferably 10 minutes may be mentioned. The formation may be carried out using thickness control to determine the thickness of the article obtained by the method. Preferably, the thickness of the article obtained by the method is in the range of 0.5 mm to 10 cm, preferably 3 mm to 5 cm, more preferably 4 mm to 2 cm. Specifically, if the article is a furniture part, the thickness of the article obtained by the method may be in the range of 5 mm to 15 mm, preferably 7 mm to 12 mm. 【0054】 The temperature applied during the formation process is such that the internal temperature of the structure reaches the glass transition temperature (T) of the polymer. g The temperature is above ). g The T of the polymer can be measured according to any method well known in the art and is generally determined using a puncture test. Therefore, depending on the properties of the polymer, the internal temperature during the forming process can be 50°C to 180°C, preferably 60°C to 180°C, more preferably 80°C to 140°C, and even more preferably 100°C to 140°C. g An internal temperature below a certain level is unfavorable because, at such an internal temperature, the polymer prevents the fibers from moving relative to each other. In addition, the T of the polymer gBelow this temperature, the structure is brittle and unable to form, and may break. Temperatures above 180°C are also unfavorable, because this can cause the fibrous material to break, especially if the fibrous material contains cellulose or lignocellulose fibers. If it is also desirable that the polymer hardens rapidly during the forming process, the internal temperature during the forming process may be 140°C to 180°C, 150°C to 180°C, preferably 155°C to 170°C. As mentioned above, the forming time may be at least 5 seconds, and up to 24 hours may be mentioned. Immediately after forming, the internal temperature of the non-flat article may be 100°C to 130°C. 【0055】 In some embodiments, water present in the structure subjected to the formation may be removed during the formation. In some embodiments, at least 5%, preferably at least 20%, more preferably at least 40%, and more preferably at least 60% of the water present in the structure subjected to the formation is removed. At most, 100% of the water present in the structure subjected to the formation may be removed during the formation of the article. If polymerization occurs simultaneously with the formation, this also includes water generated during the polymerization of the resin. In the context of this specification, the expression “simultaneously,” when used in the context of a method step, means that the steps overlap at least partially in time. For example, if polymerization, void reduction, and formation are performed simultaneously in a press, the void reduction may be started and / or completed before the polymerization is completed. 【0056】 In some embodiments, polymerization takes place during the forming process. In this embodiment, the degree of polymerization of the resin in the resulting non-planar article is at least 0.1, and particularly at least 0.2, higher than the degree of polymerization of the resin in the structure entering the forming process. 【0057】 In some embodiments, the degree of polymerization of the resin in the resulting non-flat article from the forming step is at least 0.7, particularly at least 0.8, and even more particularly at least 0.9, and the degree of polymerization of the resin in the structure entering the forming step is in the range of 0 to 0.7, preferably in the range of 0.3 to 0.6. 【0058】 To facilitate the removal of water in the form of vapor (i.e., by evaporation), the material of the structure may be in contact with a water-permeable part during the forming. For example, a porous shell may be used when forming the structure. It has been found to be advantageous to use a porous shell, where the sides of the porous shell in contact with the means for applying force to the structure each have parallel grooves containing pores. The use of such a porous shell can be advantageous. This is because it minimizes the distance that water (vapor) has to travel to exit the structure, thus reducing the pressure rise. The shell may also be used to create a specific pattern on the surface of the non-flat article. 【0059】 The porous shell may have a pore density of 300 to 1000 pores / m 2 , preferably 400 to 900 pores / m 2 , more preferably 500 to 800 pores / m 2 . The pores may have a diameter of 0.5 mm to 3 mm, preferably 1 mm to 2 mm. Suitable pore diameters can be readily determined by those skilled in the art considering the degree of polymerization of the polymer in the composite material. When the degree of polymerization of the polymer is lower (e.g., about 0.40), it may be desirable to use small pores to avoid leakage. On the other hand, when the degree of polymerization is high (or higher), the pore diameter may be larger. The pores are preferably uniformly dispersed throughout the shell. 【0060】 The method of the present invention enables the manufacture of articles with enhanced visual appeal. This is because the structure is pressed before or during the formation to reduce the void ratio. As a result, the distance between fibers is shortened, and the resin occupies most or all of the remaining voids. In this way, a non-flat article with a homogeneous surface can be obtained after the formation. The surface uniformity of the non-flat article can be determined visually (with the naked eye), for example, by determining the "gloss" of the surface, by counting cracks and areas where the resin is not completely impregnated ("white spots") on the surface, and / or by touching (feeling) the smoothness of the surface. 【0061】 After the forming process, the formed article is released from the mold. 【0062】 After formation, the polymer in the article may have a degree of polymerization of at least 0.5, preferably at least 0.6, more preferably at least 0.7, and particularly at least 0.8. If the degree of polymerization after formation is too low, one or more curing steps may be required to increase the strength of the article, as described below. At most, the theoretical degree of polymerization after formation is 1.0. The water content of the non-flat article immediately after formation is preferably less than 10% by weight, more preferably less than 5% by weight, and most preferably less than 2% by weight. If the degree of polymerization is at least 0.5 and the water content is less than 10% by weight, the non-flat article advantageously has a stable structure, thereby simplifying downstream processing (e.g., transport of the article and / or further curing steps). 【0063】 If necessary, the non-flat articles resulting from the forming process may be subjected to one or more curing processes (e.g., curing at different temperatures). Preferably, the non-flat articles are subjected to two or more curing processes. These curing processes are intended to further polymerize the polymer and thus (further) increase the strength and water resistance of the articles. Therefore, the key point of the curing process is that the polymer is at its reaction temperature. The curing process may also be performed to remove or reduce the amount of water remaining in the non-flat articles. 【0064】 Curing can be carried out using heating techniques known in the art, for example, in an oven. Various types of ovens may be used, including, but are not limited to, belt ovens, convection ovens, infrared ovens, hot air ovens, conventional baking ovens, and combinations thereof. Curing can be carried out in a single step or in multiple steps. Curing time generally ranges from 5 seconds to 3 hours, depending on the size and shape of the article and the type and temperature of the oven used. Selecting appropriate curing conditions is within the scope of those skilled in the art. 【0065】 The article can be cured at an internal temperature of 100°C to 220°C, preferably 100°C to 180°C, and more preferably 120°C to 170°C. Preferably, if the non-flat article contains natural fibers (e.g., cellulose fibers or lignocellulose fibers), the internal temperature during curing is 170°C or lower, because higher temperatures may damage these fibers. If high water resistance is desired, curing is preferably carried out at an internal temperature above 150°C. Thus, the curing temperature can be above 150°C to 220°C, preferably above 150°C to 180°C, and more preferably above 150°C to 170°C. The internal temperature is measured during curing or immediately after the article is removed from the curing means, e.g., oven or press. 【0066】 Articles obtained using the method according to the present invention can be cured in two steps. This may be advantageous when the water content of non-flat articles is still relatively high, because the two-step method prevents uneven curing of non-flat articles. The first curing step is performed at an internal temperature of 80°C to 140°C, preferably 105°C to 135°C, more preferably 110°C to 130°C. Curing the article at this temperature minimizes the occurrence of blisters on the surface of the article, which would occur if the article were cured at a higher temperature. The first curing step is performed for at least 15 minutes, preferably at least 25 minutes, and preferably at least 30 minutes. It can be performed for as long as desired, but for commercial reasons, it is generally not performed for more than 3 hours. 【0067】 After the first curing step, the article may be cured in a second curing step at an internal temperature of 140°C to 220°C, preferably 140°C to 180°C. If the non-flat article contains natural fibers (e.g., cellulose fibers or lignocellulose fibers), the internal temperature during curing is preferably 170°C or lower, because higher temperatures can damage these fibers. The second curing step may still be used to increase the strength of the article if necessary. This is generally carried out for at least 60 minutes, preferably at least 90 minutes. For commercial reasons, the second curing step is generally carried out for a maximum of 3 hours. As will be apparent to those skilled in the art, a temperature gradient may also be applied during curing. 【0068】 After curing, the degree of polymerization is generally greater than 0.80, preferably greater than 0.90. Furthermore, immediately after curing, the water content of the article is generally less than 10% by weight (calculated relative to the total weight of the article), preferably less than 5% by weight, more preferably less than 2% by weight, and most preferably less than 1% by weight. Depending on storage conditions, the water content of the article may increase after curing. 【0069】 Depending on the degree of polymerization, the polymer in the article slowly hydrolyzes when in contact with water. Therefore, a lower degree of polymerization may be selected if a certain degree of degradability of the article is desired (for example, in packaging applications). In some embodiments, the degree of polymerization of the polymer in the article is 0.6 to 1.0, preferably 0.8 to 1.0, and more preferably 0.95 to 1.00. However, a higher degree of polymerization is preferred if a more stable material is desired. Therefore, in some embodiments, the degree of polymerization of the polymer in the non-planar article is at least 0.90, preferably at least 0.95, and most preferably at least 0.98. Generally, non-planar articles with a lower degree of polymerization are more flexible than non-planar articles with a higher degree of polymerization. 【0070】 Depending on the degree of polymerization, the polymer in the non-planar article can be hydrolyzed, so that in some embodiments, the polymer in the non-planar article decomposes slowly, leaving the fibrous material and the polymer available for biological degradation. Thus, in some embodiments, the non-planar article is biologically biodegradable. Furthermore, since the polymer consists essentially of carbon, hydrogen, and oxygen atoms, it exhibits a clean combustion profile and good suitability for disposal as organic waste. 【0071】 As will be apparent to those skilled in the art, the degree of polymerization of the article obtained after curing is at least as high as, and generally higher than, the degree of polymerization of the article obtained after formation. The degree of polymerization of the article obtained after formation is at least as high as, and generally higher than, the degree of polymerization of the article subjected to the formation process. The degree of polymerization of the structure obtained after pre-curing is higher than the degree of polymerization of the structure before pre-curing. The degree of polymerization of the resin supplied to the structure is at most as high as, and generally lower than, the degree of polymerization of the resin after curing (after formation). 【0072】 Therefore, as stated above, a general method for manufacturing non-flat articles is: A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization greater than 0 to 1.0, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 40% by weight, and The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, and, The T of the polymer g Forming the structure into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. to attach This process includes, Here, polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously, or Polymerization (if carried out) and reduction of the void ratio are performed simultaneously, followed by formation, or Polymerization (if carried out) and reduction of void ratio are carried out sequentially in any order, followed by formation, or Polymerization (if carried out) is followed by a reduction and formation of the void ratio, where the formation is carried out simultaneously with or following the reduction of the void ratio. 【0073】 It is preferable to cure the non-flat article obtained after formation. Therefore, a preferred general method for manufacturing a non-flat article is: A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization greater than 0 to 1.0, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 40% by weight. The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, Polymer T g Forming the structure into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. To attach to, Here, polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously, or Polymerization (if carried out) and reduction of the void ratio are performed simultaneously, followed by formation, or Polymerization (if carried out) and reduction of void ratio are carried out sequentially in any order, followed by formation, or After polymerization (if carried out), void reduction and formation are performed, where the formation is performed either simultaneously with or after the void reduction, To cure a non-flat article at an internal temperature of at least 80°C. This includes the following steps. 【0074】 It is also preferable that polymerization, reduction of void ratio, and formation occur (substantially) simultaneously. Therefore, a more preferred general method for producing non-flat articles is: A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization greater than 0 to 1.0, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.5 to 0.98 and a water content of less than 40% by weight. The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, Polymer T gForming the structure into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. To attach to, Here, polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously, and To cure a non-flat article at an internal temperature of at least 80°C. This includes the following steps. 【0075】 First Embodiment In a first embodiment of the present invention, the structure is subjected to polymerization, pressing, and forming processes simultaneously. This embodiment is described below. The first embodiment can be combined with any of the fibrous materials, resins, and general method features described above. 【0076】 Therefore, in the first embodiment, a method for manufacturing a non-flat article, the method is A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 40% by weight. The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, Polymer T g Forming the structure into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. to attach The process includes, Here, polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously. The above method is disclosed. 【0077】 It is preferable to cure the non-flat article obtained after formation. Therefore, a preferred method for manufacturing the non-flat article of the first embodiment is: A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 40% by weight. The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, Polymer T g Forming the structure into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. To attach to, Here, polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously, To cure a non-flat article at an internal temperature of at least 80°C. This includes the following steps. 【0078】 The structure is preferably pre-cured. Therefore, a more preferred method for manufacturing the non-flat article of the first embodiment is: A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 40% by weight. The structure is pre-cured at an internal temperature of 60°C to 140°C. The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, Polymer T g Forming the structure into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. To attach to, Here, polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously, and To cure a non-flat article at an internal temperature of at least 80°C. This includes the following steps. 【0079】 In a first embodiment, the fibrous material in the structure comprises at least partially a resin as defined herein. Preferably, the resin is provided to at least 80%, more preferably at least 90%, and most preferably at least 95% of the fibers of the fibrous material. The more fibers of the fibrous structure are provided with resin, the easier and more consistent the production of non-planar articles from the structure becomes. Those skilled in the art will understand that providing the resin can be done using methods well known in the art, such as spraying, dipping, or roll coating. For example, the resin may be sprayed onto one or more sides of the fibrous material. In some embodiments, the resin is provided on one or more layers of the fibrous material, respectively. 【0080】 In the first embodiment, providing the resin may mean providing the resin to the entire fiber surface. Alternatively, the resin may be provided to only a portion of the fiber surface. In the forming process described below, the fibers within the structure are pressed together, thereby resulting in the redistribution of the resin. If only a portion of the fiber surface was covered with resin before the compression process, this redistribution may provide the resin to a larger portion of the fiber surface. In the final article, it is preferable that the resin is provided to essentially all fiber surfaces, because the interaction of the resin with the fibers is at least partially involved in obtaining the desirable properties of the article in question. 【0081】 In the first embodiment, the structure has a water content of 1% to 40% by weight, calculated relative to the total weight of the structure, immediately before its formation. In some embodiments, the water content of the structure is 1% to 35% by weight, preferably 2% to 30% by weight, more preferably 3% to 25% by weight, and most preferably 4% to 20% by weight. A low water content of the structure is advantageous because it reduces the time required to form the structure and reduces the waste of resin due to leakage from the structure. 【0082】 In the first embodiment, the degree of polymerization of the polymer in the structure entering the formation step may be greater than 0 to 0.7, preferably 0.1 to 0.6, more preferably 0.1 to 0.5, even more preferably 0.2 to 0.5, and even more preferably 0.3 to 0.5. 【0083】 In the first embodiment, the viscosity of the resin is 0.55·10 -3 The pressure may be Pa·s to 50 Pa·s, preferably 0.05 Pa·s to 2.5 Pa·s, and more preferably 0.1 Pa·s to 0.15 Pa·s (at room temperature). 【0084】 In the first embodiment, the structure may be pre-formed before molding, for example, by fitting the structure into a mold. It may be advantageous to line the mold with a Teflon coating, at least partially. This helps to prevent the structure from adhering to the mold. 【0085】 In the first embodiment, the structure is formed (i.e., shaped) by applying force to it, and the structure has an internal temperature sufficient to evaporate water. The forming process results in an article that is remarkably strong, as well as increased surface uniformity and scratch resistance. The forming process is generally carried out in a mold, where the mold is defined as a hollow shape capable of accommodating the structure before the forming process, thereby ensuring that an article having the desired shape is obtained after the forming process. 【0086】 In the first embodiment, the force is generally applied by pressing the structure in a mold, preferably a mold coated with Teflon material. The pressure applied may be 2 to 40 bar, preferably 5 to 30 bar, more preferably 10 to 20 bar. The pressure may be applied for a total duration of at least 5 seconds. The longer the duration of the formation, the greater the stability of the article. It will be understood that forming for a very long period of time is not commercially attractive. Therefore, a maximum duration of 24 hours, preferably 1 hour, more preferably 10 minutes may be mentioned. Preferably, the forming time is less than 10 minutes. The forming may be carried out using thickness control, which determines the thickness of the article obtained by the method. Preferably, the thickness of the article obtained by the method is in the range of 0.5 mm to 10 cm, preferably 3 mm to 5 cm, more preferably 4 mm to 2 cm. Specifically, if the article is a furniture component, the thickness of the article obtained by this method may be in the range of 5 mm to 15 mm, preferably 7 mm to 12 mm. 【0087】 In the first embodiment, the temperature applied in the forming process is such that the internal temperature of the structure is the T of the polymer. gThe temperature is above the threshold at which water is removed. Therefore, depending on the properties of the polymer and the pressure, the temperature during the forming process may be 50°C to 180°C, preferably 80°C to 140°C, more preferably 100°C to 140°C. g A lower internal temperature is disadvantageous because, at such internal temperatures, the polymer prevents the fibers from moving relative to each other. In addition, the T of the polymer g At temperatures lower than this, the structure becomes brittle and may break. Internal temperatures above 180°C are also unfavorable because they can damage the fibrous material. As mentioned above, the forming time can be at least 5 seconds. Up to 24 hours may be mentioned. Preferably, the forming time is less than 10 minutes. Immediately after forming, the internal temperature of the non-flat article can be between 80°C and 140°C. 【0088】 In the first embodiment, water present in the structure being formed may be removed during the formation. In the first embodiment, at least 5%, preferably at least 20%, more preferably at least 40%, and more preferably at least 60% of the water present in the structure being formed may be removed. At most, 100% of the water present in the structure being formed may be removed during the formation of the article. 【0089】 In the first embodiment, the material of the structure may come into contact with the water-permeable portion during its formation in order to facilitate the removal of water in the form of vapor (i.e., by evaporation). For example, a porous shell may be used when forming the structure. It has been found to be advantageous to use a porous shell, where the sides of the porous shell that come into contact with the means for applying force to the structure are provided with parallel grooves, each containing a hole. The use of such a porous shell is advantageous because it minimizes the distance that water (vapor) must travel, and therefore reduces the pressure rise. The shell may also be used to create a specific pattern on the surface of a non-flat article. 【0090】 In the first embodiment, the porous shell has 300 to 1000 pores / m 2 Preferably 400-900 holes / m 2 More preferably 500-800 holes / m 2 The pore density may be , and the pores may have a diameter of 0, 5 mm to 3 mm, preferably 1 mm to 2 mm. A suitable pore size can be easily determined by those skilled in the art, taking into account the degree of polymerization of the polymer in the composite material. If the degree of polymerization of the polymer is lower (e.g., about 0.40), it may be desirable to use smaller pores to avoid leakage. On the other hand, if the degree of polymerization is high (or higher), the pore size may be larger. The pores are preferably uniformly dispersed throughout the shell. 【0091】 In the first embodiment, after the forming step, the formed article is released from the mold. 【0092】 In the first embodiment, after formation, the polymer in the article may have a degree of polymerization of at least 0.5, preferably at least 0.6, and more preferably at least 0.7. If the degree of polymerization after formation is too low, a further curing step may be required to increase the strength of the article. At most, the theoretical degree of polymerization after formation is 1.0. The water content immediately after formation is preferably less than 20% by weight, more preferably less than 10% by weight, and most preferably less than 5% by weight. When the degree of polymerization is at least 0.5 and the water content is less than 20% by weight, the non-flat article advantageously has a stable structure, thereby simplifying downstream processing (e.g., transport of the article and / or further curing steps). 【0093】 Second Embodiment In a second embodiment of the present invention, the structure is subjected to a drying step, followed sequentially by a simultaneous polymerization step, a pressing step, and a forming step. This embodiment is described below. The second embodiment can be combined with any of the features of the fibrous material, the resin, and the general method. 【0094】 Therefore, in the second embodiment, a method for manufacturing a non-flat article, the method is A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of 20% to 60% by weight. The structure is dried at a temperature between 10°C and less than 60°C. To obtain a structure comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 20% by weight. The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, Polymer T g Forming the structure into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. to attach This process includes, Here, polymerization (if carried out), reduction of void fraction, and formation are performed (substantially) simultaneously. The above method is disclosed. 【0095】 The non-flat article is preferably cured. Therefore, a preferred method for manufacturing the non-flat article of the second embodiment is: A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of 20% to 60% by weight. The structure is dried at a temperature between 10°C and less than 60°C. To obtain a structure comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 10% by weight. The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, Polymer T g Forming the structure into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 10% by weight. to attach Here, polymerization (if carried out), reduction of void ratio, and formation are performed (substantially) simultaneously, and To cure a non-flat article at an internal temperature of at least 80°C. This includes the following steps. 【0096】 In a second embodiment, the fibrous material in the structure comprises at least partially the resin as defined herein. Preferably, the resin is provided to at least 80%, more preferably at least 90%, and most preferably at least 95% of the fibers of the fibrous material. The more fibers of the fibrous structure are provided with resin, the easier it is to manufacture non-planar articles from the structure. Those skilled in the art will understand that providing the resin can be done using methods well known in the art, such as spraying, dipping, or roll coating. For example, the resin may be (roll) coated on one or more sides of the fibrous material. In some embodiments, the resin is provided to one or more layers of the fibrous material, respectively. Preferably, the resin is diluted with water to facilitate impregnation of the fibrous material. 【0097】 In the second embodiment, it is preferable that the resin is provided on essentially all fiber surfaces in the final article, because the interaction of the resin with the fibers is at least partially involved in obtaining the desirable properties of the article in question. 【0098】 In a second embodiment, the structure has a water content of 10% to 60% by weight, calculated relative to the total weight of the structure, immediately after impregnation with the (diluted) resin. In some embodiments, the water content of the structure is 15% to 55% by weight, preferably 20% to 50% by weight, and more preferably 20% to 45% by weight. 【0099】 In the second embodiment, the viscosity of the resin may be 1 Pa·s or less, preferably 0.5 Pa·s or less, more preferably 0.1 Pa·s or less, and even more preferably 0.01 Pa·s or less (at room temperature). 1-10 -5 The minimum viscosity of Pa·s may be mentioned. 【0100】 In the second embodiment, the structure is then subjected to a drying step to remove excess water. The drying step can be carried out under conditions suitable for removing water. Polymerization of the resin does not occur during the drying. Drying may be carried out at a temperature below 60°C, preferably between 10°C and 60°C, more preferably between 10°C and 50°C, even more preferably between 20°C and 50°C, and more preferably between 30°C and 50°C. The drying time is preferably up to 3 hours, more preferably up to 2 hours, and most preferably up to 1 hour. A minimum drying time of 5 minutes may be mentioned. The drying can reduce the water content, calculated relative to the total weight of the structure, to less than 20% by weight, preferably less than 10% by weight, more preferably less than 5% by weight, and most preferably less than 2% by weight. 【0101】 In the second embodiment, the structure after drying and before formation has a water content of 0.1% to 20% by weight, calculated relative to the total weight of the structure. In some embodiments, the water content of the structure is 0.1% to 20% by weight, preferably 1% to 10% by weight, and more preferably 1% to 5% by weight. A low water content of the structure is advantageous because it reduces the time required to form the structure, reduces the waste of the resin due to leakage from the structure, and helps to avoid any difficulties that may be encountered during formation if the water content is high (too high). 【0102】 In a second embodiment, the (dried) structure may be subjected to a (pre)curing step before formation. The (pre)curing may be carried out at an internal temperature of 60°C to 140°C, preferably 80°C to 120°C. The (pre)curing may be carried out for at least 5 minutes, preferably at least 10 minutes, more preferably at least 1 hour. Generally, the precuring is carried out in an oven. It is advantageous to carefully control the humidity in the oven, as moisture is removed during drying and therefore high humidity is counterproductive. Thus, the humidity in the oven during (pre)curing may be less than 50%, preferably less than 40%. The (pre)curing may result in a degree of polymerization of at least 0.6, preferably at least 0.7, more preferably at least 0.8. 【0103】 In a second embodiment, the force applied during formation may be applied by pressing the structure within a mold, preferably coated with polytetrafluoroethylene material or other material that simplifies the removal of the non-flat article from means for forming the non-flat article after formation. The pressure applied may be 2 to 40 bar, preferably 5 to 30 bar, more preferably 10 to 20 bar. The pressure may be applied for a total duration of at least 5 seconds. The longer the formation duration, the greater the stability of the article. It will be understood that forming for very long periods is not commercially attractive. Therefore, a maximum duration of 24 hours, preferably 1 hour, more preferably 10 minutes, most preferably 5 minutes may be mentioned. Preferably, the formation time is less than 10 minutes. The formation may be carried out using thickness control, which determines the thickness of the article obtained by the method. Preferably, the thickness of the article obtained by the method is in the range of 0.5 mm to 10 cm, preferably 3 mm to 5 cm, more preferably 4 mm to 2 cm. Specifically, if the article is a furniture component, the thickness of the article obtained by this method may be in the range of 5 mm to 15 mm, preferably 7 mm to 12 mm. 【0104】 In the second embodiment, the temperature applied in the forming step is the T of the polymer. g Higher than. Therefore, depending on the properties of the polymer, the temperature during the forming process may be 60°C to 180°C, preferably 80°C to 140°C, more preferably 100°C to 140°C. As described above, the T of the polymer g Internal temperatures below a certain temperature are unfavorable because, at such temperatures, the polymer prevents the fibers from moving relative to each other. Internal temperatures above 180°C are also unfavorable because, as this can damage the fibrous material. 【0105】 In the second embodiment, since almost all water evaporates during the drying process, it is not necessary to remove water during formation. The drying process in this embodiment is advantageous because drying is very efficient as a result of the high void ratio and surface area of ​​the fibrous material used. Low temperatures and short drying times can yield satisfactory results. Nevertheless, some water may still be removed during formation. For example, at least 5%, preferably at least 10%, more preferably at least 20%, and more preferably at least 30% of the water still present in the structure being formed may be removed. At most, 100% of the water still present in the structure being formed may be removed during the formation of the article. 【0106】 In the second embodiment, after formation, the polymer in the article may have a degree of polymerization of at least 0.5, preferably at least 0.6, more preferably at least 0.7, and most preferably at least 0.8. If the degree of polymerization after formation is too low, a further curing step may be required to increase the strength of the article. At most, the theoretical degree of polymerization after formation is 1.0. The water content immediately after formation is preferably less than 10% by weight, more preferably less than 5% by weight, and most preferably less than 2% by weight. When the degree of polymerization is at least 0.5 and the water content is less than 10% by weight, the non-planar article advantageously has a stable structure, thereby simplifying downstream processing (e.g., transport of the article and / or further curing steps). 【0107】 Third Embodiment In a third embodiment of the present invention, the structure defined in claim 1 is subjected to a drying step and a polymerization step, followed by a simultaneous pressing step and a forming step, in sequence. This embodiment is described below. The third embodiment can be combined with any of the features of the fibrous material and the resin, or the features of the general method. 【0108】 Therefore, in the third embodiment, a method for manufacturing a non-flat article, the method is A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of 20 to 60% by weight. The structure is dried at a temperature between 10°C and less than 60°C. The structure is pre-cured at an internal temperature of 60°C to 140°C. To obtain a structure comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization greater than 0 to 1.0, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 20% by weight. The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, Polymer T g The structure is formed into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5, preferably at least 0.6, and a water content of less than 20% by weight. to attach This process includes, Here, polymerization (if carried out), reduction of void fraction, and formation are performed (substantially) simultaneously. The above method is disclosed. 【0109】 Non-flat articles are preferably cured. Therefore, a preferred method for manufacturing a non-flat article of the third embodiment is: A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of 20% to 60% by weight. The structure is dried at a temperature between 10°C and less than 60°C. The structure is pre-cured at an internal temperature of 60°C to 140°C. To obtain a structure comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization greater than 0 to 1.0, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98 and a water content of less than 10% by weight. The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, Polymer T g The structure is formed into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5, preferably at least 0.6, and a water content of less than 10% by weight. To attach to, Here, polymerization (if carried out), reduction of void ratio, and formation are performed (substantially) simultaneously, and To cure a non-flat article at an internal temperature of at least 80°C. This includes the following steps. 【0110】 Preferably, pre-curing results in a structure having a degree of polymerization of 0.5 to 1. Therefore, a more preferred method for producing the non-planar article of the third embodiment is: A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of greater than 0 to 1.0, preferably greater than 0 to 0.6, wherein the structure has a void ratio of 0.5 to 0.98 and a water content of 20% to 60% by weight. The structure is dried at a temperature between 10°C and less than 60°C. The structure is pre-cured at an internal temperature of 60°C to 140°C. To obtain a structure comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of 0.5 to 1.0, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.5 to 0.98 and a water content of less than 5% by weight. The structure is formed by the following process Pressing to reduce the void ratio, Polymer T g The structure is formed into a non-flat article by applying force at an internal temperature exceeding a certain value, wherein the resulting non-flat article has a degree of polymerization of at least 0.5, preferably at least 0.6, and a water content of less than 5% by weight. To attach to, Here, the reduction and formation of the void ratio are carried out (substantially) simultaneously, and To cure a non-flat article at an internal temperature of at least 80°C. This includes the following steps. 【0111】 In a third embodiment, the fibrous material in the structure comprises at least partially the resin as defined herein. Preferably, the resin is provided to at least 80%, more preferably at least 90%, and most preferably at least 95% of the fibers of the fibrous material. The more fibers of the fibrous structure are provided with resin, the easier it is to manufacture non-planar articles from the structure. Those skilled in the art will understand that providing the resin can be done using methods well known in the art, such as spraying, dipping, or roll coating. For example, the resin may be (roll) coated on one or more sides of the fibrous material. In some embodiments, the resin is provided to one or more layers of the fibrous material, respectively. Preferably, the resin is diluted with water to facilitate impregnation of the fibrous material. 【0112】 In the third embodiment, it is preferable that the resin is provided on essentially all fiber surfaces in the final article, because the interaction of the resin with the fibers is at least partially involved in obtaining the desirable properties of the article in question. 【0113】 In a third embodiment, the structure has a water content of 10% to 60% by weight, calculated relative to the total weight of the structure, immediately after impregnation with the (diluted) resin. In some embodiments, the water content of the structure is 15% to 55% by weight, preferably 20% to 50% by weight, and more preferably 20% to 45% by weight. 【0114】 In the third embodiment, the viscosity of the resin may be 1 Pa·s or less, preferably 0.5 Pa·s or less, more preferably 0.1 Pa·s or less, and even more preferably 0.01 Pa·s or less (at room temperature). 1-10 -5 The minimum viscosity of Pa·s may be mentioned. 【0115】 In a third embodiment, the structure is then subjected to a drying step to remove excess water. The drying step can be carried out under conditions suitable for removing water. No polymerization of the resin occurs during the drying. Drying may be carried out at a temperature below 60°C, preferably between 10°C and 60°C, preferably between 10°C and 50°C. The drying time is preferably up to 3 hours, more preferably up to 2 hours, and most preferably up to 1 hour. A minimum drying time of 5 minutes may be mentioned. Drying can reduce the water content, calculated relative to the total weight of the structure, to less than 20% by weight, preferably less than 10% by weight, more preferably less than 5% by weight, and most preferably less than 2% by weight. 【0116】 In the third embodiment, the structure after drying and before formation has a water content of 0.1% to 20% by weight, calculated relative to the total weight of the structure. In some embodiments, the water content of the structure is 0.1% to 20% by weight, preferably 1% to 15% by weight, and more preferably 1% to 10% by weight. A low water content of the structure is advantageous because it reduces the time required to form the structure, reduces resin waste due to leakage from the structure, and helps to avoid any difficulties that may be encountered during formation if the water content is too high. 【0117】 In a third embodiment, the (dried) structure is subjected to a (pre)curing step before formation. The (pre)curing can be carried out at an internal temperature of 60°C to 140°C, preferably 60°C to 120°C, more preferably 80°C to 120°C. The (pre)curing can be carried out for at least 5 minutes, preferably at least 10 minutes, more preferably at least 1 hour. Generally, the (pre)curing is carried out in an oven. It is advantageous to carefully control the humidity in the oven, as moisture is removed during drying and therefore high humidity is counterproductive. Thus, the humidity in the oven during (pre)curing can be less than 50%, preferably less than 40%. The (pre)curing can result in a degree of polymerization of at least 0.6, preferably at least 0.7, more preferably at least 0.8. 【0118】 In a third embodiment, the force applied during formation may be applied by pressing the structure within a mold, preferably coated with polytetrafluoroethylene material or other material that simplifies the removal of the non-flat article from means for forming the non-flat article after formation. The pressure applied may be 2 to 40 bar, preferably 5 to 30 bar, more preferably 10 to 20 bar. The pressure may be applied for a total duration of at least 5 seconds. The longer the formation duration, the greater the stability of the article. It will be understood that forming for very long periods is not commercially attractive. Therefore, a maximum duration of 24 hours, preferably 1 hour, more preferably 10 minutes, and most preferably 5 minutes may be mentioned. Preferably, the formation time is less than 10 minutes, more preferably less than 5 minutes. The formation may be carried out using thickness control to determine the thickness of the article obtained by the method. Preferably, the thickness of the article obtained by this method is in the range of 0.5 mm to 10 cm, preferably 3 mm to 5 cm, and more preferably 4 mm to 2 cm. Specifically, if the article is a furniture part, the thickness of the article obtained by this method may be in the range of 5 mm to 15 mm, preferably 7 mm to 12 mm. 【0119】 In the third embodiment, the temperature applied in the forming step is the T of the polymer. g Higher than. Therefore, depending on the properties of the polymer, the temperature during the forming process may be 60°C to 180°C, preferably 80°C to 140°C, more preferably 100°C to 140°C. As described above, the T of the polymer g Internal temperatures below a certain temperature are unfavorable because, at such temperatures, the polymer prevents the fibers from moving relative to each other. Internal temperatures above 180°C are also unfavorable because this can damage the fibrous material. 【0120】 In the third embodiment, since almost all water evaporates during the drying and pre-curing steps, it is not necessary to remove water during formation. The drying step in this embodiment is advantageous because drying is very efficient as a result of the high void ratio and surface area of ​​the fibrous material used. Low temperatures and short drying times can yield satisfactory results. Nevertheless, some water may still be removed during formation. For example, at least 5%, preferably at least 10%, more preferably at least 20%, more preferably at least 30% of the water present in the structure to be formed. If a shell is present during formation to facilitate water evaporation, at least 20%, preferably at least 40%, and more preferably at least 60% of the water still present in the structure formed may be removed. At most, 100% of the water still present in the structure formed may be removed during the formation of the article. 【0121】 In the third embodiment, after formation, the polymer in the article may have a degree of polymerization of at least 0.5, preferably at least 0.6, more preferably at least 0.7, and most preferably at least 0.8. If the degree of polymerization after formation is too low, a further curing step may be required to increase the strength of the article. At most, the theoretical degree of polymerization after formation is 1.0. The water content immediately after formation is preferably less than 10% by weight, more preferably less than 5% by weight, and most preferably less than 2% by weight. When the degree of polymerization is at least 0.5 and the water content is less than 10% by weight, the non-planar article advantageously has a stable structure, thereby simplifying downstream processing (e.g., transport of the article and / or further curing steps). 【0122】 Fourth Embodiment In a fourth embodiment of the present invention, the structure defined in claim 1 is subjected to a polymerization step and a pressing step, respectively, where the pressing results in a flat article. The flat article is then subjected to a polymer T gThe product is subjected to a forming process at a higher internal temperature. This embodiment is described below and can be combined with the features of the general method, the second embodiment and the third embodiment. 【0123】 Accordingly, in the fourth embodiment, the provided or obtained structure is pressed to form a flat article. In one variation of the fourth embodiment, the polymerization and pressing steps are performed simultaneously to reduce the void ratio, followed by the forming step. In another variation of the fourth embodiment, the polymerization and pressing steps for reducing the void ratio are performed sequentially in any order, followed by the forming step. In yet another variation of the fourth embodiment, pressing and forming are performed after the polymerization step to reduce the void ratio, and the forming is performed simultaneously with or following the pressing for reducing the void ratio. 【0124】 The flat articles may be cooled to room temperature. The resulting flat articles are generally very rigid, especially when cured at temperatures above 100°C for several hours. The pressure applied to form the flat articles is 2 to 40 bar (i.e., kg / 1cm² of structure). 2 ), preferably 5 to 30 bar, more preferably 10 to 20 bar. For example, the pressure may be applied for a total duration of at least 5 seconds to a maximum of 24 hours. Surprisingly, these flat articles are formed from polymer T g The flat article can be reshaped by heating it to an internal temperature higher than that and then forming it into a non-flat article (by pressing and forming). Depending on the particular embodiment, this may enable the manufacture of complex non-flat articles without forming means that can withstand high temperatures and pressures for extended periods. Heated molds that can withstand high pressures are expensive, and therefore, methods that do not require such molds are advantageous. 【0125】 In a fourth embodiment, the force applied during forming may be applied by pressing the structure within a mold, preferably a mold coated with Teflon material. The pressure applied may be 1 atm to 40 bar, preferably 5 to 30 bar, more preferably 10 to 20 bar. The pressure may be applied for a total duration of at least 5 seconds. The longer the forming duration, the greater the stability of the article. It will be understood that forming for very long periods is not commercially attractive. Therefore, a maximum duration of 24 hours, preferably 1 hour, more preferably 10 minutes may be mentioned. Preferably, the forming time is less than 10 minutes. The forming may be carried out using thickness control, which determines the thickness of the article obtained by the method. Preferably, the thickness of the article obtained by the method is in the range of 0.5 mm to 10 cm, preferably 3 mm to 5 cm, more preferably 4 mm to 2 cm. Specifically, if the article is a furniture component, the thickness of the article obtained by this method may be in the range of 5 mm to 15 mm, preferably 7 mm to 12 mm. 【0126】 In the fourth embodiment, the temperature applied in the forming step is the T of the polymer. g Higher than. Therefore, depending on the properties of the polymer, the temperature during the forming process may be 60°C to 180°C, preferably 80°C to 140°C, more preferably 100°C to 140°C. g An internal temperature lower than 180°C is unfavorable because, at such temperatures, the polymer prevents the fibers from moving relative to each other. An internal temperature above 180°C is also unfavorable because, as this can damage the fiber material. Furthermore, an internal temperature of the polymer's T g If the temperature is lower than this, the structure will be brittle and may break. As mentioned above, the formation time can be at least 5 seconds. Up to 24 hours may be mentioned. Preferably, the formation time is less than 10 minutes. Immediately after formation, the internal temperature of the non-flat article can be 80-140°C. 【0127】 Non-flat articles The present invention also relates to articles that can be obtained by methods according to the present invention. Non-flat articles have a bending strength greater than 20 MPa, as determined, for example, using ASTM D7264. 【0128】 Accordingly, the present invention relates to a non-planar article comprising a fibrous material impregnated with a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid (preferably having 3 to 15 carbon atoms), wherein the polymer has a degree of polymerization of at least 0.5, the non-planar article has a water content of less than 20% by weight, and a flexural strength greater than 20 MPa, as determined, for example, using ASTM D7264. The non-planar article may have a void ratio of 0.8 or less, preferably 0.7 or less, more preferably 0.5 or less, even more preferably 0.4 or less, even more preferably 0.35 or less, even more preferably 0.3 or less, and most preferably 0.2 or less. 【0129】 The properties of polymers and fillers in non-planar articles according to the present invention are referenced above in the context of the methods according to the present invention. Any preferred embodiments specified for polymers and fibrous materials (layers thereof) used in the methods according to the present invention also apply to polymers and fibrous materials (layers thereof) in articles according to the present invention. 【0130】 In some embodiments, the non-flat article has a flexural strength (measured, for example, using a three-point bending test as defined in ASTM D7264) of at least 20 MPa, preferably at least 25 MPa, more preferably at least 30 MPa, particularly at least 40 MPa, and most preferably at least 50 MPa. Generally, the flexural strength should be as high as possible. An upper limit for the flexural strength of the non-flat article may be, for example, 200 MPa. 【0131】 The density of the non-flat article is at least 0.3 g / cm³. 3 In particular, at least 0.7 g / cm³ 3Preferably at least 0.8 g / cm³ 3 , more preferably at least 0.9 g / cm³ 3 Preferably at least 1.0 g / cm³ 3 Preferably at least 1.1 g / cm³ 3 , may be. If the non-flat article contains natural fibers (e.g., cellulose fibers, e.g., hemp), the non-flat article may contain up to 1.4 g / cm³. 3 It may be desirable to have a density of 1.4 g / cm³. Non-flat articles containing fiber materials with fibers having a higher intrinsic density are desirable. 3 It can have a higher density. 【0132】 In embodiments aimed at producing highly durable and high-strength non-flat articles, the articles of the present invention have a degree of polymerization of at least 0.8, preferably at least 0.9, and more preferably at least 0.95. 【0133】 The water content of the non-flat article is less than 20% by weight, calculated relative to the total weight of the non-flat article. The water content is preferably 15% by weight or less, more preferably 10% by weight or less. In some embodiments, the water content of the non-flat article is as defined above after storage at 50% humidity (relative) and 20°C for 24 hours, more preferably after 48 hours, and most preferably after 72 hours. As described above, water resistance increases, for example, with increasing curing temperature. 【0134】 In a particular embodiment, the present invention relates to a non-planar article that can be obtained by a method according to the present invention, comprising 30 to 80% by weight of hemp fibers, preferably randomly oriented hemp fibers, and 20 to 70% by weight of a resin, preferably a resin derived from glycerol and citric acid, wherein the polymer in the non-planar article has a degree of polymerization of at least 0.8, particularly at least 0.9, and even more particularly at least 0.95, and the non-planar article has a water content of up to 20% by weight, particularly at least 15% by weight, and even more particularly at least 10% by weight, a void ratio of up to 0.6, preferably at least 0.5, more preferably at least 0.4, and even more preferably at least 0.35, and a water content of 0.6 to 1.4 g / cm³3 Preferably 0.8 to 1.4 g / cm³ 3 The present invention relates to the above-mentioned non-flat articles having a density of and a bending strength of at least 30 MPa, most preferably at least 40 MPa (measured, for example, using a three-point bending test as defined in ASTM D7264). 【0135】 (Nonwoven) hemp fibers have been found to be advantageously used in the method according to the present invention because hemp fibers provide a very desirable formability to the structure. Therefore, in some embodiments, the non-planar article is a fiberboard, where the fiber material comprises hemp fibers. The fiberboard may contain at least 10% by weight, preferably at least 20% by weight, most preferably at least 30% by weight of the polymer as defined herein. In some embodiments, the fiberboard may contain up to 80% by weight, preferably up to 70% by weight, more preferably up to 60% by weight, most preferably up to 50% by weight of the polymer as defined herein. If the amount of polymer in the fiberboard is too high or too low, its mechanical properties (e.g., its flexural strength) will be reduced. 【0136】 It will be apparent to those skilled in the art that preferred embodiments expressed in the methods of the present invention can be combined, provided they are not mutually exclusive. Similarly, preferred embodiments expressed in the methods according to the present invention also apply to non-planar articles obtained by the methods according to the present invention, non-planar articles according to the present invention, and structures for use in the methods according to the present invention. 【0137】 Examples The present invention will be described by the following embodiments, but will not be limited thereto. 【0138】 Example 1: Preparation of polyester polymer solution Glycerol (1.0 kg, purity >99%) and citric acid (2.0 kg, purity >99%) were combined in a stirred and heated reaction vessel. Boric acid (9 g, 0.5 mm / m, purity >99%) was added. Within approximately 15 minutes, the mixture was heated to 135°C and held at that temperature for 15 minutes. The mixture was then diluted with tap water to a water content of 40-50% by weight. The mixture was then cooled. 【0139】 Example 2: Manufacturing of a seat for a chair Step 1: Preparation of the hemp mat Four hemp mats were cut from a hemp roll (15 x 1 m, 10 mm thick, made of Hempflax). The dimensions of the cut hemp mats were as shown in Figure 1. 【0140】 Step 2: Impregnation of the hemp mat Each of the four hemp mats was impregnated with the resin obtained in Example 1. First, the resin was uniformly sprayed onto one side of the hemp mat. Next, the hemp mat was turned over and the resin was sprayed onto the other side. The resin impregnation was carried out at room temperature. The total amount of resin sprayed onto the four mats was calculated to be 40% by weight relative to the amount of resin before dilution and the total weight of the four mats. 【0141】 Step 3: Pre-curing of the hemp mat The impregnated hemp mats were pre-cured at 105°C for 30 minutes. They were then cooled to room temperature. After they had cooled, the four hemp mats were stacked on top of each other to create a structure having four layers of composite material containing hemp and polymer. 【0142】 Step 4: Pressing the hemp mat The structure was placed inside a preheated mold (145°C) coated with Teflon (to prevent the structure from sticking to the preheated mold). Next, a porous shell, each containing numerous parallel grooves with numerous pores, was placed on top of the structure. The porous shell contained pores with a diameter of 1.5 mm, at a rate of 650 pores / m². 2It had a pore density of . Next, the structure was pressed at a temperature of 145°C (internal temperature of 115-125°C) for a total of 10 minutes. In this example, the pores of the porous shell help the evaporation of water from the structure. No steam explosion occurred. The article was removed from the mold. The article thus obtained had a smooth and uniform surface, determined by tactile and visual inspection of the number of cracks and the amount of area not completely impregnated with resin. 【0143】 Step 5: Post-curing of the seat for the chair Next, the item was placed in an oven and preheated to 120°C. The chair was first cured at this temperature for 30 minutes. No blistering was observed on the surface of the chair. Next, the chair was cured at 160°C for 105 minutes. Then, the seat for the chair was slowly cooled to room temperature. 【0144】 The seat portion has a density of 0.9 g / cm³. 3 It had an overall density of 0.85-0.95, a degree of polymerization of 0.85-0.95, and a water content of approximately 4% by weight. The flexural strength was in the range of 50 MPa (transverse fiber direction) to 70 MPa (fiber direction). 【0145】 Next, the seat was transformed into a chair using methods (and / or machining) known in the art. A chair including a seat obtained using the methods disclosed herein is shown in Figures 3 and 4. 【0146】 The resulting chair met the industrial requirements for safety, strength, and durability. Specifically, the chair met the requirements of European standards EN 1728:2000, 6.2.1 and EN 1728:2000, 6.7. Figure 4 shows the test equipment used in the industrial test. Figure 5 shows the back of the chair after being subjected to a force of 300 N for more than 100,000 cycles. As can be seen from the photograph, no wear was observed during the test. This is quite remarkable considering the load placed on the chair during the test. 【0147】 Furthermore, no delamination was observed at any point during the process. 【0148】 Example 3 Step 1: Preparation of the hemp mat Four hemp mats were cut from a hemp roll (15 x 1 m, 10 mm thick, made of Hempflax). The dimensions of the cut hemp mats were as shown in Figure 1. 【0149】 Step 2: Impregnation of the hemp mat Each of the four hemp mats was impregnated with the resin obtained in Example 1. The resin was uniformly distributed on one side of the surface of each hemp mat. Next, the hemp mats were turned over, and pressure was applied to all of the mats with a rolling pin until all the fibers in the mats were wet. The resin impregnation was carried out at room temperature. 【0150】 Step 3: Drying the hemp mat The impregnated hemp mats were dried at 40°C for 12 hours. Next, they were cooled to room temperature. After they had cooled, the four hemp mats were stacked on top of each other to create a structure having four layers of composite material containing hemp and polymer. 【0151】 Steps 4 and 5: Formation and post-curing of the hemp mat Next, the structure was formed and cured as described in Example 2, steps 4 and 5. Regarding the product of Example 2, the resulting product was 0.9 g / cm³. 3 It had an overall density of 0.85-0.95, a degree of polymerization of 0.85-0.95, and a water content of approximately 4% by weight. The flexural strength was in the range of 50 MPa (transverse fiber direction) to 70 MPa (fiber direction). 【0152】 The resulting non-flat articles were processed to create a seat for a chair. The resulting seat was strong enough to withstand 190 kg (applied to the curved portion of the chair's back, between the seat and the backrest) without breaking. No delamination was observed at any point during the process. 【0153】 Example 4 Step 1: Preparation of the hemp mat Four hemp mats were cut from a hemp roll (15 x 1 m, 10 mm thick, made of Hempflax). The dimensions of the cut hemp mats were as shown in Figure 1. 【0154】 Step 2: Impregnation of the hemp mat Each of the four hemp mats was impregnated with the resin obtained in Example 1. The resin was uniformly distributed on one side of the surface of each hemp mat. Next, the hemp mats were turned over, and pressure was applied to all of the mats with a rolling pin until all the fibers in the mats were wet. The resin impregnation was carried out at room temperature. 【0155】 Step 3: Drying and curing of the hemp mat The impregnated hemp mat was dried at 40°C for 12 hours and then immediately subjected to the pre-curing process described in step 4. 【0156】 Step 4: Curing of the hemp mat The dried, impregnated hemp mats were pre-cured at 105°C for 4 hours. Next, the four hemp mats were stacked on top of each other to create a structure having four layers of composite material containing hemp and polymer. 【0157】 Steps 5 and 6: Formation and post-curing of the hemp mat Next, the structure was formed and cured as described in Example 2, Steps 4 and 5. 【0158】 Regarding Example 2, the product was 0.9 g / cm³. 3 It had an overall density of 0.85 to 0.95, a degree of polymerization of 0.85 to 0.95, and a water content of approximately 4% by weight. The flexural strength was in the range of 50 MPa (transverse fiber direction) to 70 MPa (fiber direction). 【0159】 The resulting chair seat was strong enough to withstand 190 kg (applied to the curved portion of the chair's back, between the seat and the backrest) without fracture. No delamination was observed at any point during the process. 【0160】 Interestingly, Examples 2 to 4 yield chair seats of different colors without the addition of any colorants. Chairs obtained by the methods described in Examples 2 to 4 are shown in Figure 6. The ability to control the color of non-flat articles without the addition of colorants is a further improvement over conventional methods. 【0161】 Example 5: Glass fiber filler In this example, 390 g / m² 2 A twill 2 / 2 woven fiberglass mat with a basis weight was used. The mat was woven from fiberglass with a linear density of 2.55 g / cm². 【0162】 A 20cm x 10cm square fiberglass mat was cut using special scissors for fibers. The layers were weighed and then impregnated with the resin of Example 1. The mat was then pre-cured at 80°C for 45 minutes. 【0163】 Ten impregnated mats were stacked on top of each other. The stack was placed in a hot press having a flat aluminum mold and an aluminum mold with a curved surface, resulting in a non-flat product, which was pressed at 150°C for 20 minutes at 15 kg / cm². 2 The sample was pressed. After pressing, the sample was cured at 160°C for 1 hour. A solid and strong composite material was obtained. The volume fiber fraction was 55%. 【0164】 Mechanical tests were performed using a Testometric M350-20CT test bench, yielding a flexural strength of 191 MPa, a flexural modulus of 14 GPa, and an interlaminar shear strength of 13.5 MPa. 【0165】 Example 6: Other fibers Using the method of Example 5, 160 g / m² 2 A composite product was manufactured from a carbon fiber mat having a basis weight and 3000 filaments / fiber in a twill 2 / 2 configuration, where the carbon fiber had a linear density of 1.76 g / cm³. In addition to its attractive appearance, the resulting product exhibited good flexural strength, flexural modulus, and interlaminar shear strength. 【0166】 Experiments using woven aramid sheets also yielded composite materials with excellent properties. In one embodiment, the present invention may be configured as follows. [Section 1] A method for manufacturing a non-flat article, the method is A structure is prepared comprising a fibrous material and a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization greater than 0 to 1.0, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98, and the structure has a water content of less than 40% by weight, and The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, and, The structure is formed into a non-flat article by applying force at an internal temperature exceeding the glass transition temperature (Tg) of the polymer, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. to attach This process includes, Here, polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously, or Polymerization (if carried out) and reduction of the void ratio are performed simultaneously, followed by formation, or Polymerization (if carried out) and reduction of void ratio are carried out sequentially in any order, followed by formation, or Following polymerization (if carried out), the void ratio is reduced and formed, wherein the formation is performed simultaneously with or after the reduction of the void ratio. The aforementioned method. [Section 2] The method according to item 1, wherein polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously. [Section 3] The method according to claim 1 or 2, wherein the structure has a void ratio of 0.4 to 0.98, preferably 0.5 to 0.98, more preferably 0.6 to 0.98, and even more preferably 0.7 to 0.95. [Section 4] The method according to claim 1 or 2, wherein the fibrous material comprises fibers having a fiber length of 1 to 10 cm, preferably 2 to 7 cm, and more preferably 3 to 5 cm. [Section 5] The method according to any one of claims 1 to 4, wherein the structure has a polymer content of 20 to 70% by weight, preferably 25 to 45% by weight or 30 to 60% by weight, relative to the weight of the fiber material. [Section 6] The method according to any one of items 1 to 5, wherein water evaporates through multiple pores during formation. [Section 7] The method according to any one of claims 1 to 6, wherein, after the formation, the article is cured in a (first) curing step at an internal temperature of at least 80°C, preferably 80 to 140°C, for at least 15 minutes, wherein preferably a second curing step follows the first curing step, wherein the article is cured at an internal temperature of 140 to 220°C, preferably 140 to 170°C, for at least 60 minutes. [Section 8] The method according to any one of claims 1 to 7, wherein the fiber material is a natural fiber material, preferably selected from the group consisting of fibers derived from hemp, flax, cotton, kenaf, jute, ramie, sisal, coconut, hair, wool, silk, and feathers, or the fiber material is a synthetic fiber material, preferably selected from fibers derived from viscose, glass, polyester, carbon, aramid, nylon, acrylic, and / or polyolefins. [Section 9] The aliphatic polyalcohol said above, Dialcohols, preferably 1,2-propanediol, 1,3-propanediol and 1,2-ethanediol, One or more polyalcohols having at least three hydroxyl groups, for example, selected from the group consisting of glycerol, sorbitol, xylitol and mannitol; and / or Herein, the aliphatic polycarboxylic acid comprises one or more acids selected from the group consisting of citric acid, isocitric acid, cis-aconitic acid, and trans-aconitic acid, and 3-carboxy-cis,cis-muconic acid, and preferably the aliphatic tricarboxylic acid is citric acid, according to any one of claims 1 to 8. [Section 10] The method according to any one of claims 1 to 9, wherein the article is a piece of furniture, preferably a seat, more preferably a seat for a chair or a seat for a (bar) stool. [Section 11] A structure suitable for use in the method described in any one of items 1 to 10, the structure comprising a fibrous material impregnated with a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid, wherein the structure has a void ratio of 0.3 to 0.98, the polymer has a degree of polymerization of 0.5 to 0.8, and the structure has a water content of less than 20% by weight, preferably less than 10% by weight. [Section 12] A non-flat article that can be obtained by the method described in any one of items 1 to 11, wherein the non-flat article has a bending strength of more than 20 MPa, preferably determined using ASTM D 7264. [Section 13] A non-flat article comprising a fibrous material impregnated with a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid, wherein the polymer has a degree of polymerization of at least 0.5, the non-flat article has a water content of less than 20% by weight, and the non-flat article has a flexural strength of more than 20 MPa, preferably determined using ASTM D 7264. [Section 14] The structure has a value of 0.8 or less, preferably 0.7 or less, more preferably less than 0.5. It has a void ratio of less than 0.4, even more preferably less than 0.35, and most preferably less than 0.2, and / or at least 0.7 g / cm³. 3 A non-planar article according to claim 12 or 13, comprising a polymer derived from an aliphatic polyalcohol having a density of and / or a water content of less than 10% by weight and / or 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of at least 0.6, particularly at least 0.7, more particularly at least 0.8. [Section 15] The non-flat article according to item 13 or 14, wherein the article is a furniture component, preferably a seat, more preferably a seat for a chair or a seat for a (bar) stool.

Claims

[Claim 1] A method for manufacturing a non-flat article, the method is A structure is prepared comprising a fibrous material and a resin containing a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization greater than 0 to 1.0, or a precursor monomer of such a polymer, wherein the structure has a void ratio of 0.3 to 0.98, and the structure has a water content of less than 40% by weight, and The structure is formed by the following process If the degree of polymerization is less than 0.5, polymerize to a degree of polymerization of 0.5 to 1. Pressing to reduce the void ratio, and, The structure is formed into a non-flat article by applying force at an internal temperature exceeding the glass transition temperature (Tg) of the polymer, wherein the resulting non-flat article has a degree of polymerization of at least 0.5 and a water content of less than 20% by weight. to attach This process includes, Here, polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously, or Polymerization (if carried out) and reduction of void ratio are performed simultaneously, followed by formation, or Polymerization (if carried out) and reduction of void ratio are carried out sequentially in any order, followed by formation, or Following polymerization (if carried out), the void ratio is reduced and formed, wherein the formation is performed simultaneously with or after the reduction of the void ratio. The aforementioned method. [Claim 2] The method according to claim 1, wherein polymerization (if carried out), reduction of void ratio, and formation are performed simultaneously. [Claim 3] The method according to claim 1 or 2, wherein the structure has a void ratio of 0.4 to 0.

98. [Claim 4] The method according to claim 1 or 2, wherein the fiber material includes fibers having a fiber length of 1 to 10 cm. [Claim 5] The method according to any one of claims 1 to 4, wherein the structure has a polymer content of 20 to 70% by weight relative to the weight of the fiber material and the polymer. [Claim 6] The method according to any one of claims 1 to 5, wherein water evaporates through a plurality of holes during formation. [Claim 7] The method according to any one of claims 1 to 6, wherein a curing step is performed after the formation. [Claim 8] The method according to claim 7, wherein the curing step comprises at least two steps, in which the article is cured at an internal temperature of 80 to 140°C in the first curing step, and a second curing step follows the first curing step, in which the article is cured at an internal temperature of 140 to 220°C. [Claim 9] The method according to any one of claims 1 to 8, wherein the fiber material is selected from natural fiber materials and synthetic fiber materials. [Claim 10] The aliphatic polyalcohol said above, A dialcohol selected from 1,2-propanediol, 1,3-propanediol, and 1,2-ethanediol, and A polyalcohol having at least three hydroxyl groups, selected from glycerol, sorbitol, xylitol, and mannitol. It comprises one or more compounds selected from the group consisting of; and / or, The method according to any one of claims 1 to 9, wherein the aliphatic polycarboxylic acid comprises one or more acids selected from the group consisting of citric acid, isocitric acid, cis-aconitic acid, and trans-aconitic acid, and 3-carboxy-cis,cis-muconic acid. [Claim 11] The method according to any one of claims 1 to 10, wherein the article is a furniture component. [Claim 12] A structure suitable for use in the method according to any one of claims 1 to 11, the structure comprising a fibrous material impregnated with a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid, wherein the structure has a void ratio of 0.3 to 0.98, the polymer has a degree of polymerization of 0.5 to 0.8, and the structure has a water content of less than 20% by weight. [Claim 13] A non-flat article comprising a fibrous material impregnated with a resin comprising a polymer derived from an aliphatic polyalcohol having 2 to 15 carbon atoms and an aliphatic polycarboxylic acid, wherein the polymer has a degree of polymerization of at least 0.5, the non-flat article has a water content of less than 20% by weight, and the non-flat article has a flexural strength greater than 20 MPa as determined using ASTM D 7264. [Claim 14] The article has a void fraction of 0.7 or less, and / or at least 0.7 g / cm³. ３ The non-planar article according to claim 13, comprising a polymer derived from an aliphatic polyalcohol having a density and / or a water content of less than 10% by weight and / or 2 to 15 carbon atoms and an aliphatic polycarboxylic acid having a degree of polymerization of at least 0.

7. [Claim 15] The non-flat article according to claim 13 or 14, wherein the article is a furniture component.

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