Modified polyurethane foams

Abstract

The present application relates to a PU foam comprising at least one secondary plant compound bonded, preferably covalently bonded thereto, in which the at least one secondary plant compound is introduced partially or completely in the form of wood particles.

Description

Technical Field

[0001] The present invention relates to a polymer and its production and use. Background Art

[0002] Polymers such as polyurethanes (PU) are used in various fields and are usually chemically modified to adapt to special requirements. For example, polyurethanes are used as molding materials for compression molding, as casting resins (isocyanate resins), as (textile) elastic fiber materials, polyurethane paints, and as polyurethane adhesives. Specifically, soft PU foams are mainly used as furniture upholstery materials (e.g., for furniture or car seats), as mattress foams, as carpet backing materials, for laminated textiles, as cleaning sponges, or as filter materials. The range of use of the corresponding materials can be adjusted by adding chemical additives. Therefore, it is a common practice to produce articles for different uses by correspondingly modifying PU foams by adding functional additives. For example, the water absorption rate of a mattress can be reversibly changed by mixing an additive into the polyurethane soft foam, which greatly facilitates the design of the mattress. However, such additives are usually toxic and non-biodegradable. Another example includes the use of carcinogenic activated carbon black to absorb odorants.

[0003] Therefore, a basic disadvantage of common modified PU foams is the presence of environmentally harmful functional chemicals that can be separated from the polymer and enter the environment (e.g., groundwater). Another disadvantage relates to the high dosage of functional chemicals, because in many cases, the compounds incorporated into the polymer core do not have any functional efficacy and are difficult to mobilize.

[0004] Therefore, the object of the present invention is to provide a sustainable PU foam with improved performance and high environmental compatibility. Summary of the Invention

[0005] Therefore, the present invention relates to a PU foam comprising at least one secondary plant compound bonded thereto, preferably covalently bonded thereto, wherein the at least one secondary plant compound is present partially or completely in the form of wood particles.

[0006] Surprisingly, it has been shown that the properties of the PU foams of the present invention are improved in a targeted manner by the secondary plant compounds bonded thereto, and their environmental compatibility can be enhanced. Depending on the structure and properties of the secondary plant compounds, the properties of the material can be manipulated by covalently bonding the material to a fibrous material without using toxic and / or environmentally harmful chemicals. Secondary plant compounds are natural components that are also present, for example, in daily nutrition, and thus pose no danger to the environment or humans since they are products of biological, sustainable raw materials. The secondary plant compounds are present in the PU foam partly or completely in the form of wood particles. Wood particles are biological, sustainable raw materials and enhance or expand the properties of the PU foam obtained by the secondary plant compounds.

[0007] Another aspect of the present invention relates to a method for producing a PU foam, which method comprises the steps of reacting at least one polyol component with at least one isocyanate component in the presence of a blowing agent and at least one catalyst that catalyzes the isocyanate-polyol reaction, wherein at least one secondary plant compound is mixed during the reaction of the at least one polyol component with the at least one isocyanate component, and wherein at least one secondary plant compound is present partly or completely in the form of wood particles. When producing the PU foam of the present invention, the starting materials are mixed, and the linkage of the individual components is achieved by the reaction of the isocyanate group (-N=C=O) of one molecule with the hydroxyl group (-OH) of another molecule to form a urethane group (–NH–CO–O-). By mixing at least one secondary plant compound into the reaction, the secondary plant compound can be covalently bonded to the PU foam, in particular to the isocyanate component. It has been shown that the method of the present invention allows for the production of environmentally friendly PU foams with improved properties, and the use products produced therefrom with improved properties are ecologically safe.

[0008] Another aspect of the present invention relates to a PU foam that can be obtained by the method of the present invention.

[0009] Another aspect of the present invention relates to the use of the PU foam for the production of filters, furniture upholstery, mattresses, cushions, hygiene products, cleaning sponges, and / or thermal insulation layers, preferably for use in textiles, sound insulation, and thermal insulation. Detailed Description

[0010] In the present invention, the terms "PU foam", "PUR foam" and "polyurethane foam" specifically relate to products obtainable by reacting polyisocyanates with polyols or compounds having isocyanate-reactive groups and optionally a propellant. Preferred PU foams are flexible PU foams, rigid PU foams and integral PU foams. Particular preference is given herein to conventional flexible PU foams based on ether or ester polyols, highly elastic polyurethane cold foams, viscoelastic PU foams, PU super-soft foams, semi-rigid PU foams and rigid PU foams, and PU foams having properties between these classifications.

[0011] The term "secondary plant compound" with respect to the present invention refers to substances that are neither produced in energy metabolism nor in the construction (anabolism) or degradation (catabolism) metabolism. They are produced in plants in certain cell types and differ from primary plant material in that they are not directly essential to the plant. The biosynthetic pathways leading to the production of secondary plant compounds are reviewed from the perspective of secondary metabolism. In contrast to the products of primary metabolism of plants, secondary plant compounds are specific chemical metabolites. These metabolites are generally limited to a certain type of plant or group and are derived from primary metabolism. Due to their chemical structure and functional properties, secondary plant compounds are divided into different groups such as polyphenolic compounds, carotenoids, phytoestrogens, glucosinolates, sulfides, terpenes, terpenoids, saponins, protease inhibitors, phytosterols and lectins. Secondary plant compounds such as isoprenoids, resins and terpenes are also present, for example, in wood and its particles.

[0012] At least one secondary plant compound is preferably covalently bonded to the PU foam. This means that at least one secondary plant compound is preferably covalently bonded to the isocyanate during the production of the PU foam (preferably by the reaction of a polyol with an isocyanate). This means that the secondary plant compound, which can to some extent, i.e., partially or completely, consist of wood particles, is thus integrated into the PU foam. This is particularly advantageous because it results in the distribution of at least one secondary plant compound within the PU foam. Thus, the PU foam of the present invention contains at least one secondary plant compound in its internal structure as well as on the surface. Therefore, abrasion, cutting, and similar measures on the PU foam do not cause the PU foam to lose its advantageous properties based on at least one secondary plant compound because the secondary plant compound is repeatedly "exposed" on the PU foam. As used herein, "covalently bonded" means that at least 5 wt%, preferably at least 10 wt%, more preferably at least 20 wt%, more preferably at least 40 wt%, more preferably at least 50 wt%, more preferably at least 60 wt%, more preferably at least 80 wt% of the secondary plant compound present in the PU foam of the present invention or used or added during the production of the PU foam of the present invention is actually covalently bonded in the PU foam. The proportion of covalently bonded secondary plant compound can be determined by methods known to those skilled in the art. Based on the method described in DIN 53770, an aqueous extract can be produced, for example, at a pH value of 5.5, and the secondary plant compound contained therein can be quantified and compared with the original amount of secondary plant compound used.

[0013] The PU foam of the present invention contains at least one bonded secondary plant compound, preferably a covalently bonded secondary plant compound. According to the present invention, at least one secondary plant compound can be present partially or completely in the form of wood particles. "Completely" means that all of the secondary plant compounds (i.e., 100% of the secondary plant compounds) in the PU foam of the present invention are present in the form of wood particles. "Partially" means that at least 1 wt%, preferably at least 5 wt%, more preferably at least 10 wt%, more preferably at least 20 wt%, more preferably at least 30 wt%, more preferably at least 40 wt%, more preferably at least 50 wt%, more preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt% of the secondary plant compound is contained in the PU foam in the form of wood particles.

[0014] It has been shown that the effect of at least one secondary plant compound in the PU foam is particularly significant at a certain amount. According to a preferred embodiment of the present invention, the PU foam thus contains 0.1 wt% to 10 wt%, preferably 0.2 wt% to 5 wt%, particularly preferably 0.3 wt% to 3 wt% of at least one secondary plant compound. As used herein, "wt%" refers to the entire formulation of the PU foam.

[0015] In order to provide, for example, antistatic properties, abrasion resistance, absorption properties, odor-neutralizing properties, insecticidal properties, acaricidal properties, preferably antimicrobial properties or combinations thereof, to the PU foam of the present invention, at least one secondary plant compound is preferably a terpene compound or a polyphenol compound.

[0016] Terpenes are compounds whose basic structure is based on isoprene units (C5 units). Terpenoid compounds are also based on isoprene units, which are characterized by additional functional groups, while terpenes contain only hydrocarbons. Terpenoid compounds particularly include alcohols, ethers, aldehydes, ketones, carboxylic acids, esters, and glycoside groups. Polyphenol compounds are compounds from the class of phenolic substances or hydroxyaromatic compounds. Polyphenol compounds are typically present in the outer layers of fruits, vegetables, and grains. Polyphenol compounds have several aromatic rings in their chemical structure and can contain color pigments, flavorants, and tannins, and generally protect plants from predators or can attract insects for pollination through their color. In some plants, polyphenol compounds also serve as protection for the photosynthetic apparatus due to their antioxidant action and the fact that they filter energy-rich UV-B radiation.

[0017] When classifying terpenoid compounds, a distinction is usually made between acyclic terpene structures, monocyclic terpene structures, bicyclic terpene structures, tricyclic terpene structures, tetracyclic terpene structures, pentacyclic terpene structures, and polycyclic terpene structures, i.e., molecules without rings, with one ring, two rings, three rings, four rings, five rings, or several rings. Depending on the size of the molecule, terpenoid compounds are used as fragrances (e.g., as pheromones or repellents), adhesives, and protection against viral, bacterial, and fungal diseases. Terpenoid compounds also make up a large proportion of known essential oils. Essential oils are widely used to repel insects. A large number of terpenoid compounds also exhibit antimicrobial activity. Terpenoid compounds are active against bacteria, fungi, viruses, and protozoa.

[0018] Cyclic terpenoid compounds, preferably bicyclic terpenoid compounds, are generally used as solvents in surface treatment agents, in household products (e.g., shoe polish, floor cleaning products), as fragrance additives in cosmetics, and are natural components of plant foods (e.g., in oranges, lemons, carrots).

[0019] According to the present invention, terpenoid compounds, preferably cyclic terpenoid compounds, can be covalently bonded in the PU foam to improve the properties of the PU foam. Thus, the properties of the terpenoid compounds can be "integrated" into the PU foam. Therefore, the PU foam modified in this way has the properties also exhibited by the terpenoid compounds used.

[0020] According to a preferred embodiment of the present invention, the terpene compound is a monocyclic terpene compound or a polycyclic terpene compound, preferably a bicyclic terpene compound, a tricyclic terpene compound, a tetracyclic terpene compound or a pentacyclic terpene compound. According to another preferred embodiment of the present invention, the terpene compound is a monoterpene compound selected from the group consisting of: pyrethrins, thymol, eucalyptol, cedrol, perillic acid, linalool, laureneol, citral, citronellal, geranic acid, junionone, chrysanthemol, menthol, terpineol, verbenol, carveol, piperitone and camphor, preferably pyrethrins, thymol, eucalyptol, cedrol and / or perillic acid.

[0021] Monoterpene compounds are composed of two isoprene units, i.e., having a basic structure of 10 C atoms. Monoterpene compounds are mainly used as fragrances in the industry. By covalently bonding monoterpene compounds to PU foams, for example, foams can be provided for avoiding unpleasant odors in textile products, furniture decorations, etc.

[0022] According to another preferred embodiment of the present invention, the terpene compound is a sesquiterpene compound selected from the group consisting of: farnesin, bisabolol, armillarin, merulidial, hirsutum acid, nerolidol, zingiberene, germacrane, periplanone, elemol, guaiane and cedran, preferably farnesin, bisabolol, armillarin, merulidial and / or hirsutum acid.

[0023] Sesquiterpene compounds contain three isoprene units, i.e., having a basic structure of 15 C atoms. Sesquiterpene compounds are mainly used as fragrances and flavorings.

[0024] According to another preferred embodiment of the present invention, the terpene compound is a diterpene compound selected from the group consisting of: agelasine, larixol, dehydroabietinol, abietic acid, bolegrevilol, aframodial, phytol, retinol, primaran, nimbiol, forskolin, labdanolic acid, cassainic acid, gibberellin, isopimaric acid, dehydroabietinol and abietic acid, preferably agelasine, larixol, dehydroabietinol, abietic acid, bolegrevilol and / or aframodial.

[0025] Diterpene compounds are composed of four isoprene units (2-methylbutadiene) and can be subdivided into open-chain compounds and cyclic compounds. Diterpene compounds are present, for example, in many resins and generally have anti-inflammatory properties.

[0026] According to another preferred embodiment of the present invention, the terpene compound is a sesterterpenoid compound selected from the group consisting of: ircinin, neomanoalide, cericerane and dehydroircinin.

[0027] Sesterterpenoids are composed of five isoprene units and are mainly present in lower plants, fungi or potato leaves. Among other things, sesterterpenoids are known for their antibacterial effects (e.g., ircinin). Preferably, by covalently bonding sesterterpenoids to PU foam, materials with antimicrobial properties can be provided.

[0028] According to another preferred embodiment of the present invention, the terpene compound is a triterpene compound selected from the group consisting of: limonoids, lanosterol, fusidane, fusidic acid, euphane, dammarane, cucurbitane, cucurbitacin, betulin and betulinic acid.

[0029] Triterpene compounds contain six isoprene units, i.e., a basic structure with 30 C atoms. Tetracyclic triterpene compounds (e.g., lanostane type) include the weight classes of steroids and cucurbitacins. Depending on the basic structure, pentacyclic compounds are subdivided into oleanane, ursane and lupane type triterpene compounds. These are present, for example, as triterpene alcohols and triterpene acids (resin acids and resin alcohols) or triterpene sapogenins (saponins) in resins. Many triterpene compounds have important biological functions, such as acting as hormones.

[0030] According to another preferred embodiment of the present invention, the terpene compound is a tetraterpene compound selected from the group consisting of: carotenoids, crocetin, and lycopene.

[0031] Tetraterpene compounds contain eight isoprene units, i.e., the basic structure contains 40 C atoms. Tetraterpene compounds include fat-soluble pigments (lipochromes) in archaea, bacteria, plants, and animals. They include carotenoids, pure hydrocarbons such as lycopene, and their oxygenated derivatives lutein. Bonding tetraterpene compounds to PU foam can, for example, result in foam coloring / decoloring.

[0032] According to another preferred embodiment of the present invention, the terpene compound is a polyterpene compound selected from the group consisting of: betulinol, oleanolic acid, ubiquinone, dolichol, and betulinol, preferably betulinol, oleanolic acid, ubiquinone, and / or dolichol.

[0033] According to another preferred embodiment of the present invention, the polyphenol compound is a polyhydroxyphenol, preferably tannin, suberin, or lignin.

[0034] Tannins include polyhydroxyphenols having ortho-hydroxy groups, especially derivatives (esters) of gallic acid (3,4,5-trihydroxybenzoic acid) with glucose and related sugars. Depending on their degree of condensation, tannins can be subdivided into gallotannins (e.g., glucogallin) and ellagitannins (e.g., pendunculagin). The free hydroxy groups allow crosslinking with polymers and proteins. Thus, amino acids or proteins present on the surface of cells and viruses can be absorbed by the PU foam of the present invention. Gases such as oxygen, H2S, and ammonia can also be absorbed by the reactive groups of the bonded polyphenol compounds.

[0035] Suberin is a hydrophobic biopolymer deposited in the cell walls of plants. As a hydrophobic material, suberin has the natural function of sealing roots and preventing water penetration.

[0036] Lignin contains a group of macromolecules with different monomer structural units (coumaryl alcohol, coniferyl alcohol, sinapyl alcohol, etc.). Lignin is characterized by a structure based on phenolic complexes (phenylpropanoids) having hydroxy, methoxy, and aryloxy substituents. Lignin is hydrophobic and has special absorption ability in the bonding regions of polyvalent metal ions (Fe, Mn, Cr, etc.) and in part of the UV light with wavelengths in the range of 100 nm to 300 nm.

[0037] By covalently bonding suberin and / or lignin to the PU foam, the material can, for example, obtain hydrophobic, absorption, and / or UV-resistant properties, or these properties can be improved.

[0038] According to another preferred embodiment of the present invention, the tannin is gallotannin or ellagitannin.

[0039] According to another preferred embodiment of the present invention, the polyphenolic compound is selected from the group consisting of: phytoalexins, preferably resveratrol, flavonols, preferably taxifolin, catechins, flavonoids, anthocyanins, proanthocyanidins, procyanidins, phlobaphenes, and isoflavones.

[0040] Phytoalexins are, for example, low molecular weight compounds having antimicrobial and antioxidant effects, which can be directly produced after a plant is infected with a microorganism (such as bacteria or fungi) to inhibit its spread, growth, or reproduction in the plant. By bonding phytoalexins to the PU foam, the material can thus have antimicrobial properties.

[0041] According to another preferred embodiment of the present invention, at least one secondary plant compound is a tree resin, preferably rosin, frankincense, or balsam.

[0042] Surprisingly, it has been shown that the main part of the antibiotic, especially the antimicrobial effect of the compound, is not only based on different metabolisms in microorganisms but also on the adhesive properties of solid resins (such as rosin). The physical spread of microorganisms can be prevented or inhibited by covalently bonding the tree resin to the PU foam because the microorganisms adhere to the resin due to the adhesive force.

[0043] PU foams can be subdivided, for example, into closed-cell or partially closed-cell rigid PU foams and open-cell or partially open-cell soft PU foams. Rigid PU foams are mainly used as thermal insulation materials or for building insulation. Soft PU foams are used in many technical applications in the industrial and private sectors, such as for sound insulation, for the production of mattresses, or for decorating furniture. A particularly important market for different types of PU foams, such as conventional soft foams, rigid foams based on ether or ester polyols, and foams having properties between these classifications, is, for example, the automotive industry. Here, rigid foams can be used, for example, as headliners, ester foams for the inner lining of car doors and for die-cut sun visors, and cold foams and soft foams for seat systems. Another particularly important market relates to mattresses and seat systems for, for example, living areas, offices, etc. Regarding soft foams, it is also possible to distinguish between cold soft foams and hot soft foams.

[0044] According to another preferred embodiment of the present invention, the PU foam can thus be a rigid PU foam, a soft PU foam, or a viscoelastic PU foam.

[0045] PU foams can be produced in different ways. In principle, polyurethane is produced by the addition polymerization reaction of an isocyanate component and a polyol component, as described above. In order to foam the polyurethane produced during the reaction, a blowing agent (e.g., water) can be added to the mixture of the isocyanate component and the polyol component.

[0046] The isocyanate component used in the present invention is preferably one or more organic polyisocyanates having two or more isocyanate functional groups. Generally speaking, any known aliphatic polyfunctional isocyanate, cycloaliphatic polyfunctional isocyanate, arylaliphatic polyfunctional isocyanate, and preferably aromatic polyfunctional isocyanate can be used. Examples that can be mentioned here are alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene residue, such as 1,12-dodecane diisocyanate, 2-ethyltetramethylene diisocyanate-1,4, 2-methylpentamethylene diisocyanate-1,5, tetramethylene diisocyanate-1,4, and preferably hexamethylene diisocyanate-1,6 (HMDI), cycloaliphatic diisocyanates, such as cyclohexane-1,3-diisocyanate and cyclohexane-1,4-diisocyanate and any mixture of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or simply IPDI), 2,4-hexahydrotoluene diisocyanate and 2,6-hexahydrotoluene diisocyanate and the corresponding mixtures of isomers, and preferably aromatic diisocyanates and polyisocyanates, such as 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (TDI) and the corresponding mixtures of isomers, methylene bis(phenyl isocyanate) (MDI), 2,4'-methylene bis(phenyl isocyanate) and 2,2'-methylene bis(phenyl isocyanate) and mixtures of polyphenyl polymethylene polyisocyanates (crude MDI), and mixtures of crude MDI and toluene diisocyanate (TDI). Organic diisocyanates and polyisocyanates can be used alone or in the form of a mixture. Modified isocyanates, i.e., so-called modified isocyanates, obtained by incorporating urethane, allophanate, isocyanurate, urethane, and other groups can also be used. Therefore, particularly suitable organic polyisocyanates that are particularly preferably used are various isomers of toluene diisocyanate (2,4-toluene diisocyanate and 2,6-toluene diisocyanate (TDI), in their pure form or as a mixture of isomers of different compositions), 4,4'-methylene bis(phenyl isocyanate), so-called "crude MDI" or "polymeric MDI" (in addition to the 4,4'-isomer of MDI, also containing the 2,4'-isomer and 2,2'-isomer of MDI and higher nuclear products), and a binuclear product called "pure MDI" mainly composed of a mixture of 2,4'-isomer and 4,4'-isomer or its prepolymer.

[0047] Polyols suitable as polyol components in the sense of the present invention are any organic substances having groups reactive with isocyanates, preferably OH groups. Preferred polyols are any polyether polyols and / or polyester polyols and / or aliphatic polycarbonates containing hydroxyl groups, in particular polyether polycarbonate polyols and / or polyols of natural origin, the so-called "natural oil-based polyols" (NOP) commonly used in the production of polyurethane systems, especially PU foams. Preferred polyether polyols that can be used can be prepared by known methods, for example, by anionic polymerization of alkylene oxides in the presence of alkali metal hydroxides, alkyl alcoholates or amines as catalysts and in the presence of at least one starting molecule preferably containing 2 or 3 bonded reactive hydrogen atoms; or by cationic polymerization of alkylene oxides in the presence of Lewis acids (e.g., antimony pentachloride or boron trifluoride etherate); or by double metal cyanide catalysis. Suitable alkylene oxides contain 2 to 4 carbon atoms in the alkylene residue. Examples are tetrahydrofuran, 1,3-epoxypropane, 1,2-epoxybutane or 2,3-epoxybutane; preferably ethylene oxide and 1,2-epoxypropane are used. The alkylene oxides can be used alone, cumulatively, in blocks, in an alternating sequence or as a mixture. The starting molecule can in particular be a compound having at least 2 hydroxyl groups, preferably 2 to 8 hydroxyl groups or having at least two primary amino groups in the molecule. Starting molecules that can be used are, for example, water, divalent alcohols, trivalent alcohols or tetravalent alcohols such as ethylene glycol, 1,2-propanediol and -1,3-propanediol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, castor oil, etc., higher polyfunctional polyols, especially sugar compounds such as glucose, sorbitol, mannitol and sucrose, polyvalent phenols, resoles such as the oligomeric condensation products of phenol and formaldehyde, and Mannich condensates of phenol, formaldehyde and dialkanolamine, and melamine, or amines such as aniline, EDA, TDA, MDA and PMDA, with TDA and PMDA being particularly preferred. The choice of suitable starting molecules depends on the corresponding application fields of the resulting polyether polyols during polyurethane production (for example, for the production of flexible PU foams, triols with higher molecular weights are used than for the production of rigid PU foams).

[0048] Preferred polyester polyols that can be used are esters of polyvalent aliphatic or aromatic carboxylic acids preferably having 2 to 12 carbon atoms. Examples of aliphatic carboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid and fumaric acid. Examples of aromatic carboxylic acids are phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalene dicarboxylic acids. The polyester polyols are obtained by the condensation of these polyvalent carboxylic acids with polyvalent alcohols, preferably diols or triols having 2 to 12 carbon atoms, particularly preferably 2 to 6 carbon atoms, preferably trimethylolpropane and glycerol.

[0049] Preferred polyether polycarbonate polyols that can be used are polyols containing carbon dioxide as carbonate-bonded. Since carbon dioxide is a by-product of many processes in the chemical industry, from a commercial perspective, the use of carbon dioxide as a comonomer in the polymerization of alkylene oxides is of particular interest. The partial replacement of alkylene oxides in polyols with carbon dioxide has the potential to significantly reduce the production cost of polyols. In addition, the use of CO2 as a comonomer is very beneficial ecologically because the reaction represents the conversion of a greenhouse gas into a polymer. The production of polyether polycarbonate polyols by attaching alkylene oxides and carbon dioxide to an H-functional starting material using a catalyst has long been known.

[0050] According to another preferred embodiment of the present invention, the PU foam is produced based on polyether and / or polyester polyols and toluene-2,4-diisocyanate and / or methylene bis(phenyl isocyanate).

[0051] According to another preferred embodiment of the present invention, the PU foam has open cells or closed cells. With respect to the present invention, "open cells" means that the foam has high air permeability (= porosity). The air permeability of the foam can be determined by dynamic pressure measurement of the foam. This dynamic pressure measurement can be carried out according to EN 29053. If the measured dynamic pressure is provided in mm water column, the open-cell PU foam, especially the soft PU foam, has a dynamic pressure preferably less than 100 mm, preferably ≤ 50 mm water column determined according to the described measurement method. In the present invention, "closed cells" means a foam having almost closed cells (i.e., cells with only very small openings) within the foam material. Due to the small size of the openings, air slowly re-enters after compression, which results in slower reformation. The closed-cell PU foam preferably has a dynamic pressure of at least 300 mm water column.

[0052] At least one secondary plant compound is bonded to or "integrated" into the PU foam by covalent bonding between the reactive groups of the isocyanate component and the at least one secondary plant compound. In other words, this means that there is not only an adhesive connection or a physical connection between the at least one secondary plant compound and the PU foam or its isocyanate component, but also mainly a chemical covalent bond. In addition to the secondary plant compound, the PU foam can contain additional substances that modify the properties of the material. These substances can enhance or extend the properties of the PU foam obtained by the secondary plant compound. According to another preferred embodiment of the present invention, the PU foam thus contains light stabilizers, pigments, wood particles, biocides, acaricides, and / or fungicides.

[0053] In another preferred embodiment of the present invention, the secondary plant compounds are introduced in part or in whole in the form of subdivided plant parts, preferably subdivided wood parts or wood particles, or seeds. The subdivided plant parts can enhance or extend the properties of the secondary plant compounds introduced through the non-subdivided plant parts. The subdivided plant parts can contain a specific high proportion of secondary plant compounds depending on their source. Thus, the subdivided plant parts can be introduced into the PU foam based on the natural composition of the secondary plant compounds for different applications. Preferably, the secondary plant compounds can be introduced in the form of wood particles together with other secondary plant compounds. In this way, for example, larch wood with a high content of diterpenoids can be advantageously combined with the addition of isolated (e.g., extracted) oak tannins. The introduced subdivided plant parts have the same source, or a mixture of subdivided plant parts can have different sources. Preferably, the secondary plant compounds can be introduced in part or in whole in the form of subdivided plant parts of different sources, preferably wood particles. Thus, the different natural properties of the introduced secondary plant compounds can be combined and utilized. For example, pine wood particles and clubmoss particles can be introduced in order to combine the naturally contained secondary plant compounds of the wood. Preferably, the secondary plant compounds are introduced in part or in whole in the form of subdivided wood parts or wood particles. The introduced subdivided wood parts or wood particles are preferably naturally subdivided wood parts or wood particles. The term "naturally subdivided wood parts or wood particles" refers to subdivided wood parts or wood particles that have not been processed by their carbonization, charring or combustion.

[0054] According to a preferred embodiment of the present invention, the wood particles have a particle size of less than 50 μm, preferably less than 40 μm, more preferably less than 30 μm, more preferably less than 20 μm, more preferably 0.1 μm to 20 μm, more preferably 0.5 μm to 10 μm, more preferably 1 μm to 5 μm. Such subdivided wood particles can be produced, for example, by cryogenic grinding, preferably by cryogenic grinding using an impact mill or a colloid mill.

[0055] The size of the wood particles can preferably be determined by sieve analysis according to DIN 66165-1-2016-08 or DIN 66165-2. At least 70%, preferably at least 80%, more preferably at least 90%, more preferably at least 95%, more preferably at least 99%, especially 100% of the wood particles used in the present invention have the above particle size. The wood particles can have any shape.

[0056] Surprisingly, it has been shown that introducing wood particles with a particle size of less than 50 μm results in some advantages. Wood is structured in the form of fibrils according to its biological structure and thus exhibits a defined longitudinal orientation. This structure is mainly used to maintain the mechanical strength of trees and shrubs. The fibrils are composed almost entirely of cellulose chains embedded in a mixture of (non-oriented) substances (e.g., hemicellulose, lignin) between the cells. According to the invention, this specific structure is maintained during the production of the wood particles as described above, since the wood is preferably split in the longitudinal direction, which results in an undesired fibrous longitudinal orientation of the milled material. By microscopic examination, it has been shown that the longitudinal structure of the fibrils is only disrupted when milling is carried out below the fibril diameter (approximately 0.5 mm to 0.1 mm, depending on the wood type). This is important because the introduced wood particles with a particle size greater than 50 μm have a corresponding fibril diameter and are thus prone to packing / tangling. This effect is particularly important when the wood particles are mixed into a high-viscosity polyol component. Therefore, homogenization can only be achieved with great effort and is incompatible with continuous foaming due to the "batch requirement". Such agglomerates can cause blockages in the high-pressure mixing chamber and its inlet and disproportionately impede use. It has thus surprisingly been shown that agglomeration / tangling of the introduced wood particles can be prevented at a particle size of less than 50 μm, preferably less than 30 μm. Furthermore, it has been found that the desired release of secondary plant compounds into the polyol matrix only occurs within an acceptable time period at a particle size below 50 μm, such that the time required for mixing with isocyanate is sufficient to ensure the desired covalent bonding of the secondary plant compounds to the PU foam according to the invention. It has also been shown that such fine milling can cause problems, especially for elastic coniferous wood (softwood), while cryogenic milling in the case of using liquid nitrogen or dry ice can lead to satisfactory results. In addition, the advantage of this milling variant is that reactive secondary plant compounds are protected from premature degradation (such as oxidation). Preferably, additional additives such as colorants, light protectants, UV stabilizers, and eluates of secondary plant compounds from foreign sources can be added during the milling procedure and optimal homogenization can be carried out. Any solvent (including also the water absorbed by the wood) can be evaporated during this process step and thus does not impede subsequent PU foaming.

[0057] According to another preferred embodiment of the invention, the wood particles are selected from softwood particles, preferably spruce wood particles, fir wood particles, pine wood particles, stone pine wood particles, cedar wood particles, arborvitae wood particles, yew wood particles or larch wood particles; hardwood particles, preferably beech wood particles, poplar wood particles, birch wood particles, oak wood particles or eucalyptus wood particles; or mixtures thereof.

[0058] It has been shown that it is advantageous to adjust the ratio of secondary plant compounds and wood particles in order to even more strongly emphasize the desired effect.

[0059] A further aspect of the invention relates to a method for producing the PU foam of the invention.

[0060] In the inventive production of the PU foam of the invention, preferably, at least one polyol component and at least one isocyanate component react with each other, optionally in the presence of a blowing agent, a catalyst, with a mixture of at least one secondary plant compound. The polyol components and isocyanate components that can be used according to the invention have been described above. Depending on the chain length and the number of branches of the polyol component, the mechanical properties of the PU foam may be affected. Of course, the person skilled in the art will select the corresponding amounts of the components required for the production of different PU foam types (e.g., hot, cold, ester soft PU foam or rigid PU foam) in order to obtain the corresponding desired polyurethane type, in particular PU foam type. The production of the PU foam of the invention can be carried out according to any conventional method known to the person skilled in the art. The method of the invention can be carried out continuously or discontinuously.

[0061] The catalyst that can be used according to the invention can be any catalyst for: isocyanate-polyol (urethane formation) and / or isocyanate-water (amine and carbon dioxide formation) and / or isocyanate dimerization (uretdione formation), isocyanate trimerization (isocyanurate formation), isocyanate-isocyanate with CO2 cleavage (carbodiimide formation) and / or isocyanate-amine (urea formation) and / or "secondary" crosslinking reactions, such as isocyanate-carbamate (urethtane formation) and / or isocyanate-urea (biuret formation) and / or isocyanate-carbodiimide (uretonimine formation) reactions. The suitable amount of the catalyst to be used depends on the type of the catalyst.

[0062] Suitable catalysts in the sense of the present invention are, for example, substances which catalyze one of the aforementioned conversions, in particular the gel reaction of isocyanates (isocyanate - polyol), the blowing reaction (isocyanate - water) and / or dimerization or trimerization. Such catalysts are preferably nitrogen - containing compounds, in particular amines or ammonium salts, and / or metal - containing compounds. Within the meaning of the present invention, suitable nitrogen - containing compounds as catalysts (also hereinafter referred to as nitrogen - containing catalysts) are any nitrogen - containing compounds according to the prior art which catalyze one of the above - mentioned isocyanate reactions and / or can be used for the production of polyurethanes, in particular polyurethane foams. Within the meaning of the present invention, suitable metal - containing compounds as catalysts (also hereinafter referred to as metal - containing catalysts) are all metal - containing compounds according to the prior art which catalyze any of the above - mentioned isocyanate reactions and / or can be used for the production of polyurethanes, in particular polyurethane foams. For example, they can be selected from the group of organometallic compounds or metal - organic compounds, metal - organic salts or organometallic salts, organometallic salts, inorganic metal salts, and the group of charged or uncharged metal - containing coordination compounds, in particular metal chelate complexes.

[0063] Suitable blowing agents which can be used in the sense of the present invention are gases such as liquefied CO2, and highly volatile liquids such as hydrocarbons having 4 or 5 carbon atoms, preferably cyclopentane, isopentane and n - pentane (as long as they do not consume ozone), hydrofluorocarbons, preferably HFC 245fa, HFC 134a and HFC 365mfc, and olefinic hydrofluorocarbons such as HFO 1233zd or HFO1336mzzZ, hydrochlorofluorocarbons, preferably HCFC 141b, oxygen - containing compounds such as methyl formate and dimethoxymethane. In addition to physical blowing agents, other chemical blowing agents which react with isocyanates by generating gases, such as formic acid, carbamates or carbonates, can also be used. In the case of open - cell flexible PU foams, water is preferably used as a blowing agent.

[0064] According to another preferred embodiment of the present invention, at least one secondary plant compound is mixed in the form of an extract or an eluate.

[0065] Secondary plant compounds can be obtained by methods such as steam distillation, extraction or chromatography. For example, young plants usually provide terpene hydrocarbons, while older plants increasingly provide oxygen - containing derivatives such as alcohols, aldehydes and ketones. The methods for obtaining secondary plant compounds are known in the prior art. The term "extract" as used in the present invention includes extracts having a solid, liquid and / or oily consistency obtained from plants, in particular their fruits, roots, rhizomes, stems, branches, leaves, kernels or seeds, by extraction. The "eluate" as used in the present invention refers to solid, liquid and / or oily substances separated or extracted from plants, in particular their fruits, roots, rhizomes, stems, branches, leaves, kernels or seeds.

[0066] One advantage of the extract and the eluate that can be used is the natural composition of the components of the secondary phytochemicals contained therein. A particular advantage is that the bioavailability of the secondary phytochemicals contained in the extract can be higher than when using synthetic compositions.

[0067] Another advantage of using the eluate is their better distributability in the polyol component, because for example, terpenoids are highly soluble in the polyol component in the preferably used amounts. During the polyaddition with isocyanate, there is a particularly significant uniform distribution in the foam and thus also on the accessible cell surfaces.

[0068] According to a particularly preferred embodiment of the present invention, at least one secondary phytochemical is mixed with at least one polyol component.

[0069] At least one secondary phytochemical is capable of forming a covalent bond with the reactive groups of the isocyanate component. Therefore, it is advantageous to mix at least one secondary phytochemical with at least one polyol component to prevent premature reaction between the isocyanate component and at least one secondary phytochemical.

[0070] According to another preferred embodiment of the present invention, the PU foam is used for producing filters, furniture upholstery, mattresses, cushions, hygiene products, cleaning sponges, and / or thermal insulation layers, preferably for textiles, sound insulation, and thermal insulation.

[0071] For example, the absorption properties of the foam play an important role in many applications. Here, it is important that the foam exhibits a high absorption capacity and then rapidly releases the absorbed moisture stored therein. The present invention allows the use of modified PU foams with enhanced absorption properties to absorb, for example, body fluids such as sweat, blood, or urine. Due to these properties, such PU foams are suitable for wound dressing materials.

[0072] Another application includes preventing microorganisms by absorbing and / or eliminating bacteria on filter materials, furniture upholstery, mattresses, cushions, hygiene products, medical products, cleaning products, or thermal insulation layers. Antimicrobial substances are widely used in daily life to prevent the spread of microorganisms and microbial infections, for example, in the healthcare sector, in the food industry, in agriculture, or in common household products. However, the main problem caused by the widespread use of such substances is the continuous contamination of the environment by fungicidal and / or bactericidal substances. Such contamination may ultimately lead to the development of antibiotic-resistant microbial strains. When using the present invention, the physical absorption of bacteria, viruses, molds, and / or their spores on the PU foam is a great advantage, because it allows the prevention of the use of physiologically and ecologically problematic fungicides and antibiotics.

[0073] Example

[0074] In Examples 1 to 4, open-cell flexible foams according to the prior art were produced, using propylene oxide - polyether - polyol (functionality 3, MW 3500, OH value 50), isocyanate (toluene - 2,4 - diisocyanate (TDI) 80 / 20, NCO index 105), and blowing agent (water / TDI). The resulting PU foam had a density of 45 kg / m 3 to 50 kg / m 3 .

[0075] Example 1 :

[0076] Before foaming (mixing with isocyanate), 6 wt% of micronized pine wood (fineness D50 = 15 μm), 0.7 wt% of ellagic tannins from French Limousin oak (Quercus robur), and 0.1 wt% of perillic acid (wt% refers to the entire foam formulation) were uniformly added to the polyol batch.

[0077] The resulting yellow / orange flexible PU foam showed:

[0078] a) Fungicidal properties (tested according to DIN EN 14119)

[0079] b) More than 95% inhibition rate of the fecundity of house dust mite eggs

[0080] c) Antiviral effect in in vitro tests according to ISO 18184.

[0081] Due to the properties found, this flexible PU foam is suitable for use as a filter in mouth - nose masks or as a furniture upholstery material (bedroom and / or living room).

[0082] Example 2 :

[0083] Similar to Example 1, in this example, 3 wt% of micronized larch wood (D50 = 5 μm to 10 μm), 1.5 wt% of frankincense, 0.5 wt% of thyme oil as an eluate from Thymus vulgaris (the reagents contained are especially carvacrol, thymol, cymene, geraniol, and flavonoids and tannins as polyphenolic compounds), and 0.3 wt% of HALS1 UV stabilizer (Lowilite77) for preventing discoloration were added to the polyol batch.

[0084] The resulting flexible PU foam showed:

[0085] a) Bactericidal properties (DIN EN ISO 20743)

[0086] b) Anti - inflammatory properties.

[0087] Due to the properties found, this flexible PU foam is suitable for use as a wound pad, for dressing materials, and for mattresses.

[0088] Example 3 :

[0089] Similar to Example 1, in this example, 2.5 wt% of lignin, 0.5 wt% of tannin (ellagic tannin from oak), 1.5 wt% of an eluate in a 1:1 ratio from clubmoss and eucalyptus, and 0.2 wt% of rosmarinic acid were added to the polyol batch.

[0090] The flexible PU foam obtained showed:

[0091] a) Bactericidal properties (DIN EN ISO 20743)

[0092] b) Fungicidal properties (tested according to DIN EN 14119).

[0093] Due to the properties found, this flexible PU foam is suitable for use as a filter, for face masks, wound dressings, and for mattresses.

[0094] Example 4 :

[0095] Similar to Example 1, in this example, 2 wt% of rosin from Scots pine, 0.5 wt% of an eluate in a 2:1:1 ratio from sage, rosemary, and ivy (also containing oleanolic acid), 0.3 wt% of eucalyptol from eucalyptus oil, and 0.3 wt% of a HALS1 UV stabilizer (Lowlite 77) for preventing discoloration were added to the polyol batch.

[0096] The flexible PU foam obtained showed:

[0097] a) Bactericidal properties (DIN EN ISO 20743)

[0098] b) Fungicidal properties (tested according to DIN EN 14119)

[0099] c) Acaricidal properties, especially by physical adhesion to mites and their eggs.

[0100] Due to the properties found, this flexible PU foam is suitable for mattresses and furniture upholstery, filters, especially fine particle filters for vacuum cleaners, and general hygienic uses.

[0101] Example 5 :

[0102] In this example, a closed-cell rigid foam according to the prior art was produced. It was produced using propylene oxide-polyether-polyol (functionality 6, MW 450, OH value 50), isocyanate (methylene bis(phenyl isocyanate) (MDI) 29% NCO, NCO index 110), and blowing agent (cyclopentane). The PU foam had a density of 35 kg / m 3 to 40 kg / m 3 .

[0103] Before foaming (mixing with isocyanate), 4 wt% of lignin, 2 wt% of tannins (ellagic tannins from oak), 0.2 wt% of perillic acid, and 0.3 wt% of HALS1 UV stabilizer (Lowilite 77) were added to the polyol.

[0104] Due to the addition of lignin, which acts as a pore nucleating agent, the resulting rigid PU foam has particularly fine pores. The foam shows excellent resistance to mold infestation (Aspergillus niger), and thus the foam is particularly suitable as a thermal insulation material in residential buildings.

[0105] Example 6: Dissolution Test

[0106] In the elution test with distilled water (pH 7), the foams of Examples 1 to 5 did not show an elution effect, indicating covalent bonding of the additives.

Claims

1. A polyurethane (PU) foam, said PU foam comprising at least one secondary plant compound bonded to the PU foam, wherein said at least one secondary plant compound is present partly or completely in the form of wood particles.

2. The PU foam according to claim 1, characterized in that, Said PU foam comprises 0.1% to 10% by weight, preferably 0.2% to 5% by weight, particularly preferably 0.3% to 3% by weight of said at least one secondary plant compound.

3. The PU foam according to claim 1 or 2, characterized in that Said at least one secondary plant compound is a terpene compound or a polyphenol compound.

4. The PU foam according to claim 3, characterized in that, Said terpene compound is a monocyclic terpene compound or a polycyclic terpene compound, preferably a bicyclic terpene compound, a tricyclic terpene compound, a tetracyclic terpene compound or a pentacyclic terpene compound.

5. The PU foam according to claim 3 or 4, characterized in that, Said terpene compound is a monoterpene compound selected from the group consisting of: pyrethrins, thymol, eucalyptol, thujyl alcohol, perillic acid, linalool, geraniol, citral, citronellal, geranic acid, juniperone, chrysanthemol, menthol, terpineol, verbenol, carvacrol, piperitone and camphor, preferably pyrethrins, thymol, eucalyptol, thujyl alcohol and / or perillic acid.

6. The PU foam according to any one of claims 3 to 4, characterized in that, Said terpene compound is a sesquiterpene compound selected from the group consisting of: farnesene, bisabolol, armillarisin, merulidial, chaetomellic acid, nerolidol, zingiberene, germacrane, blattellaquinone, elemol, guaiene and cedrane, preferably farnesene, bisabolol, armillarisin, merulidial and / or chaetomellic acid.

7. The PU foam according to any one of claims 3 to 4, characterized in that, Said terpene compound is a diterpene compound selected from the group consisting of: agelasine, lariciresinol, dehydroabietinol, abietic acid, brachyvertinol, aframodial, phytol, retinol, primaran, azadirachtol, forskolin, labdanoic acid, cassiaic acid, gibberellin, isopimaric acid, dehydroabietinol and abietic acid, preferably agelasine, lariciresinol, dehydroabietinol, abietic acid, brachyvertinol and / or aframodial.

8. The PU foam according to any one of claims 3 to 4, characterized in that, Said terpene compound is a sesterterpene compound selected from the group consisting of: ircinin, neomanoalide, cerane and dehydroircinin.

9. The PU foam according to any one of claims 3 to 4, characterized in that Said terpene compound is a triterpene compound selected from the group consisting of: limonoids, lanosterol, fusidane, fusidic acid, euphane, dammarane, cucurbitane, cucurbitacin, betulin and betulinic acid.

10. The PU foam according to any one of claims 3 to 4, characterized in that, Said terpene compound is a tetraterpene compound selected from the group consisting of: carotenoids, crocetin and lycopene.

11. The PU foam according to any one of claims 3 to 4, characterized in that, Said terpene compound is a polyterpene compound selected from the group consisting of: betulinol, oleanolic acid, ubiquinone, dolichol and betulinol, preferably betulinol, oleanolic acid, ubiquinone and / or dolichol.

12. The PU foam according to any one of claims 3 to 11, characterized in that, Said polyphenol compound is a polyhydroxyphenol, preferably tannin, suberin or lignin.

13. The PU foam according to claim 12, wherein Said tannin is a gallotannin or an ellagitannin.

14. The PU foam according to any one of claims 3 to 13, characterized in that, Said polyphenol compound is selected from the group consisting of: phytoalexins, preferably resveratrol, flavonols, preferably taxifolin, catechins, flavonoids, anthocyanins, proanthocyanidins, procyanidins, phlobaphenes and isoflavones.

15. The PU foam according to any one of claims 1 to 14, characterized in that, The at least one secondary plant compound is a tree resin, preferably rosin, frankincense or balsam.

16. The PU foam according to any one of claims 1 to 15, characterized in that, The PU foam is a rigid PU foam, a flexible PU foam or a viscoelastic PU foam.

17. The PU foam according to any one of claims 1 to 16, wherein The PU foam is produced based on polyether and / or polyester polyol and toluene-2,4-diisocyanate and / or methylene bis(phenyl isocyanate).

18. The PU foam according to any one of claims 1 to 17, characterized in that, The PU foam has open cells or closed cells.

19. The PU foam according to any one of claims 1 to 18, characterized in that, The PU foam contains a light stabilizer, a pigment, a biocide, an acaricide and / or a fungicide.

20. The PU foam according to any one of claims 1 to 20, characterized in that, The wood particles have a particle size of less than 50 μm, preferably less than 40 μm, more preferably less than 30 μm, more preferably less than 20 μm, more preferably from 0.1 μm to 20 μm.

21. The PU foam according to any one of claims 1 to 20, characterized in that, The wood particles are selected from softwood particles, preferably spruce wood particles, fir wood particles, pine wood particles, stone pine wood particles, cedar wood particles, arborvitae wood particles, yew wood particles or larch wood particles; hardwood particles, preferably beech wood particles, poplar wood particles, birch wood particles, oak wood particles or eucalyptus wood particles; or a mixture thereof.

22. A method for producing a PU foam according to any one of claims 1 to 21, the method comprising the following steps: React at least one polyol component with at least one isocyanate component in the presence of a blowing agent and at least one catalyst, the at least one catalyst catalyzing the isocyanate-polyol reaction, wherein at least one secondary plant compound is mixed during the reaction of the at least one polyol component with the at least one isocyanate component, and wherein the at least one secondary plant compound is present partially or completely in the form of wood particles.

23. The method according to claim 22, characterized in that When the at least one secondary plant compound is present partially in the form of wood particles, the at least one secondary plant compound is mixed in the form of an extract or an eluate.

24. The method according to claim 22 or 23, characterized in that, Mix the at least one secondary plant compound with the at least one polyol component.

25. A PU foam obtainable by the method according to any one of claims 22 to 24.

26. Use of the PU foam according to any one of claims 1 to 21 or 25 for the production of filters, furniture upholstery, mattresses, cushions, hygiene products, cleaning sponges and / or thermal insulation layers, preferably for use in textiles, sound insulation and thermal insulation.