Modified pu foam

Abstract

The present application refers to a PU foam that comprises at least one secondary plant substance which is preferably covalently bound thereto, the at least one secondary plant substance being added to some extent or completely in the form of wood particles.

Description

[0001] MODIFIED PU FOAM

[0002] TECHNICAL FIELD

[0003] The present invention relates to a polymer and the preparation and use thereof.

[0004] BACKGROUND OF THE INVENTION

[0005] Polymers such as polyurethanes (PU) are used in a variety of fields and are often chemically modified to meet specific requirements. Polyurethanes are used, for example, as molding compounds for compression molding, as casting resins (isocyanate resins), as (textile) elastic fibers, polyurethane varnishes, and as polyurethane adhesives. Soft PU foams, in particular, are used primarily as upholstery material (e.g. for furniture or car seats), as mattress foam, as carpet backing material, for textile lamination, as cleaning sponges, or as filter material. The application of the respective material can be adapted by adding chemical additives. The production of a wide variety of everyday objects by modifying PU foams with functional additives is therefore common practice.The water absorption of mattresses, for example, can be reversibly modified by adding additives to flexible polyurethane foams, which significantly simplifies mattress design. However, such additives are often toxic and non-biodegradable. Another example involves the use of carcinogenic activated carbon to absorb odors.

[0006] A major disadvantage of commonly modified PU foams is the presence of environmentally harmful functional chemicals that can dissolve from the polymer and enter the environment (e.g., groundwater). Another disadvantage concerns the high usage quantities of these functional chemicals, as the compounds embedded in the polymer core often have no functional effectiveness or are difficult to mobilize.

[0007] It is therefore an object of the present invention to provide a sustainable PU foam which has modified properties and a high level of environmental compatibility.

[0008] SUMMARY OF THE INVENTION

[0009] Therefore, the present invention relates to a PU foam comprising at least one secondary plant substance preferably covalently bound thereto, wherein the at least one secondary plant substance is present partially or entirely in the form of wood particles.

[0010] Surprisingly, it has been shown that the properties of the PU foam according to the invention are specifically modified by the bound secondary plant metabolite, and its environmental compatibility is increased. Depending on the structure and properties of the secondary plant metabolite, the properties of the material can be influenced by covalent bonding to polyurethane without the use of toxic and / or environmentally harmful chemicals. Secondary plant metabolites are natural components that are also found in our daily diet, for example, and therefore pose no danger to the environment or humans, as they are made from organic, sustainable raw materials. The secondary plant metabolites are present partially or entirely in the PU foam in the form of wood particles. The wood particles are organic, sustainable raw materials and reinforce or enhance the properties of the PU foam obtained by the secondary plant metabolites.

[0011] Another aspect of the present invention relates to a process for producing PU foam comprising the step 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 which catalyzes the isocyanate-polyol reactions, wherein at least one secondary plant substance is added during the reaction of the at least one polyol component with the at least one isocyanate component, wherein the at least one secondary plant substance is present partially or entirely in the form of wood particles. In the production of the PU foam according to the invention, the starting materials are mixed, the linking of the individual components taking place by the reaction of an isocyanate group (-N=C=O) of one molecule with a hydroxy group (-OH) of another molecule to form a urethane group (-NH-CO-O-).By adding at least one secondary plant substance to the reaction, the secondary plant substance can covalently bond to the PU foam, particularly to the isocyanate component. It has been shown that the process according to the invention can be used to produce an environmentally friendly PU foam with modified properties, and that consumer products made from it with modified properties are ecologically safe.

[0012] A further aspect of the present invention relates to PU foam obtainable by the process according to the invention.

[0013] Another aspect of the present invention relates to the use of a PU foam for the production of filters, upholstery, mattresses, pillows, hygiene articles, cleaning sponges and / or insulating layers, preferably in textiles, sound insulation or thermal insulation.

[0014] DESCRIPTION OF THE EMBODIMENTS

[0015] In the present invention, the terms "PU foam", "PUR foam" and "polyurethane foam" refer in particular to a product obtainable by reacting polyisocyanates and polyols or compounds with isocyanate-reactive groups and optionally a blowing agent. Preferred PU foams are flexible PU foams, rigid PU foams and integral PU foams. Particularly preferred here are conventional flexible PU foams based on ether or ester polyols, highly elastic polyurethane cold-cure foams, viscoelastic PU foams, hypersoft PU foam, semi-rigid PU foams and rigid PU foams, as well as PU foams whose properties lie between these classifications.

[0016] The term "secondary plant substances" in relation to the present invention refers to substances that are produced neither in energy metabolism nor in anabolic or catabolic metabolism. They are produced in certain plant cell types and are distinguished from primary plant substances in that they are not directly essential for the plant. Biosynthetic pathways that lead to the production of secondary plant substances are summarized under the term "secondary metabolism." In contrast to the products of primary plant metabolism, secondary plant substances are specific chemical metabolites. These metabolites are usually limited to a specific plant species or group and are derived from primary metabolism.Based on their chemical structure and functional properties, secondary plant substances are divided into various groups, such as polyphenols, carotenoids, phytoestrogens, glucosinolates, sulfides, terpenes, terpenoids, saponins, protease inhibitors, phytosterols, and lectins. Secondary plant substances such as isoprenoids, resins, and terpenes are also present in wood and its particles.

[0017] The at least one secondary plant substance is, preferably covalently, bound to PU foam. This means that the at least one secondary plant substance is preferably covalently bound to the isocyanates during production of the PU foam, preferably the reaction of polyols with isocyanates in the PU foam. This means that the secondary plant substance, which can consist proportionally and thus partly or entirely of wood particles, is integrated into the PU foam. This is particularly advantageous since it leads to a distribution of the at least one secondary plant substance within the PU foam. The PU foam according to the invention therefore comprises the at least one secondary plant substance both in its internal structure and on the surface. Abrasion, cutting and the like.Measures taken on the PU foam do not result in the PU foam losing its advantageous properties due to the at least one secondary plant substance, since the secondary plant substances are repeatedly "exposed" on the PU foam. "Covalently bound", as used here, means that at least 5% by weight, preferably at least 10% by weight, even more preferably at least 20% by weight, even more preferably at least 40% by weight, even more preferably at least 50% by weight, even more preferably at least 60% by weight, even more preferably at least 80% by weight, of the secondary plant substances present in the PU foam according to the invention or used or added during the production of the PU foam according to the invention are actually covalently bound in the PU foam. The proportion of covalently bound secondary plant substances can be determined by methods known to the person skilled in the art.Based on the procedure described in DIN 53770, an aqueous extract can be prepared, for example at a pH value of 5.5, the secondary plant substances contained therein can be quantified and compared with the amount of secondary plant substances originally used.

[0018] The PU foam according to the invention comprises at least one, preferably covalently bound, secondary plant substance. According to the invention, the at least one secondary plant substance can be present partially or entirely in the form of wood particles. "Entirely" means that all secondary plant substances in the PU foam according to the invention (i.e., 100% of the secondary plant substances) are present as wood particles. "Proportionately" means that at least 1% by weight, preferably at least 5% by weight, even more preferably at least 10% by weight, even more preferably at least 20% by weight, even more preferably at least 30% by weight, even more preferably at least 40% by weight, even more preferably at least 50% by weight, even more preferably at least 60% by weight, even more preferably at least 70% by weight, even more preferably at least 80% by weight, even more preferably at least 90% by weight, of the secondary plant substances are comprised in the PU foam in the form of wood particles.

[0019] It has been shown that the effect of the at least one secondary plant substance in the PU foam is particularly evident at a certain amount. According to a preferred embodiment of the present invention, the PU foam therefore comprises 0.1 to 10 wt.%, preferably 0.2 to 5 wt.%, particularly preferably 0.3 to 3 wt.%, of the at least one secondary plant substance. "Wt.%," as used here, refers to the overall formulation of the PU foam. In order to impart, for example, antistatic, abrasion-resistant, absorbent, odor-neutralizing, insecticidal, acaricidal, preferably antimicrobial properties, or a combination thereof, to the PU foam according to the invention, the at least one secondary plant substance is preferably a terpenoid or a polyphenol.

[0020] Terpenes are compounds whose basic structure is built on isoprene units (C5 units). Terpenoids are also built on isoprene units, which are characterized by additional functional groups, whereas terpenes consist of pure hydrocarbons. Terpenoids include, among others, alcohol, ether, aldehyde, ketone, carboxylic acid, ester, and glycoside groups. Polyphenols are chemical compounds from the group of phenols or hydroxyaromatics. Polyphenols are usually found in the outer layers of fruits, vegetables, and grains. Polyphenols have several aromatic rings in their chemical structure and can contain pigments, flavors, and tannins. They usually protect plants from predators or can attract insects for pollination with their color. In some plants, polyphenols also serve as protection for the photosynthesis apparatus due to their antioxidant effect and the filtering of high-energy UV-B radiation.

[0021] To classify terpenoids, a general distinction is made between acyclic, mono-, bi-, tri-, tetra-, penta-, and polycyclic terpene structures—molecules with, without, one, two, three, four, five, or more rings, respectively. Depending on their molecular size, terpenoids serve as fragrances (e.g., pheromones or repellents), as adhesives, and as protection against viral, bacterial, and fungal diseases. Terpenoids also make up a large proportion of known essential oils. Essential oils are widely used to repel insects. A large number of terpenoids also possess antimicrobial activity. Terpenoids are active against bacteria, fungi, viruses, and protozoa.

[0022] Cyclic terpenoids, preferably bicyclic terpenoids, are often used as solvents in surface treatment agents, in household products (e.g. shoe polishes, floor cleaning agents), as fragrance additives in cosmetics and are a natural component of plant foods (e.g. in oranges, lemons, carrots).

[0023] According to the invention, terpenoids, preferably cyclic terpenoids, can be covalently bound in the PU foam to modify the properties of the PU foam accordingly. This makes it possible to "integrate" terpenoid properties into the PU foam. PU foam modified in this way thus exhibits properties that are also exhibited by the terpenoids used.

[0024] According to a preferred embodiment of the present invention, the terpenoid is a monocyclic or polycyclic terpenoid, preferably a bicyclic, tricyclic, tetracyclic, or pentacyclic terpenoid. According to a further preferred embodiment of the present invention, the terpenoid is a monoterpenoid selected from the group consisting of pyrethrin, thymol, cineole, thujanol, perillic acid, linalool, myrcenol, citral, citronellal, geranic acid, junione, chrysanthemol, menthol, terpineol, verbenol, carveol, piperitone, and camphor, preferably pyrethrin, thymol, cineole, thujanol, and / or perillic acid.

[0025] Monoterpenoids consist of two isoprene units, forming a basic structure with 10 carbon atoms. Monoterpenoids are primarily used in industry as fragrances. For example, the covalent bonding of monoterpenoids to PU foam can produce a foam that is used to prevent unpleasant odors in textiles, upholstery, etc.

[0026] According to a further preferred embodiment of the present invention, the terpenoid is a sesquiterpenoid selected from the group consisting of farnesin, bisabolol, armillarin, merulidial, hirsutic acid, nerolidol, zingiberene, germacrane, periplanon, elemol, gua an and cedrane, preferably farnesin, bisabolol, armillarin, merulidial and / or hirsutic acid.

[0027] Sesquiterpenoids comprise three isoprene units, i.e., a basic structure with 15 carbon atoms. Sesquiterpenoids are predominantly used as fragrances and flavorings. According to a further preferred embodiment of the present invention, the terpenoid is a diterpenoid selected from the group consisting of agelasin, larixol, dehydroabietinol, abietic acid, bolegrevilol, aframodial, phytol, retinol, primarane, nimbiol, forskolin, labdanolic acid, cassaic acid, gibberelan, isopimaric acid, dehydroabietinol, and abietic acid, preferably agelasin, larixol, dehydroabietinol, abietic acid, bolegrevilol, and / or aframodial.

[0028] Diterpenoids are composed of four isoprene units (2-methylbutadiene) and can be divided into open-chain and cyclic compounds. Diterpenoids are found in many resins, for example, and often exhibit anti-inflammatory properties.

[0029] According to a further preferred embodiment of the present invention, the terpenoid is a sesterpenoid selected from the group consisting of ircinin, neomanoalid, cericeran and dehydroircinin.

[0030] Sesterterpenoids consist of five isoprene units and are found primarily in lower plants, fungi, or potato leaves. Sesterpenoids are known, among other things, for their antibacterial effects (e.g., ircinin). Preferably, the covalent bonding of sesterpenoids to PU foam can be used to create a material with antimicrobial properties.

[0031] According to a further preferred embodiment of the present invention, the terpenoid is a triterpenoid selected from the group consisting of limonoids, lanosterol, fusidan, fusidic acid, euphan, dammarane, cucurbitan, cucurbitacin, betulin and betulinic acid.

[0032] Triterpenoids comprise six isoprene units, thus forming a basic structure with 30 carbon atoms. Tetracyclic triterpenoids (lanosterane type, for example) include the important group of steroids and cucurbitacins. Pentacyclic compounds are classified according to their basic structure into oleanane, ursane, or lupane triterpenoids. These occur, for example, as triterpenoid alcohols and triterpenoid acids in resins (resino acids and resinols) or as triterpenoid sapogenins (saponins). Many triterpenoids have important biological functions, such as hormones.

[0033] According to a further preferred embodiment of the present invention, the terpenoid is a tetraterpenoid selected from the group consisting of carotene, crocetin and lycopene.

[0034] Tetraterpenoids comprise eight isoprene units, meaning the basic structure consists of 40 carbon atoms. Tetraterpenoids include fat-soluble pigments (lipochromes) found in archaea, bacteria, plants, and animals. These include carotenes, pure hydrocarbons such as lycopene, and their oxygen-containing derivatives, the xanthophylls. The binding of a tetraterpenoid to PU foam, for example, can lead to the coloration / discoloration of the foam.

[0035] According to a further preferred embodiment of the present invention, the terpenoid is a polyterpenoid selected from the group consisting of betulaprenol, oleanolic acid, ubiquinone, dolochol, and betulaprenols, preferably betulaprenol, oleanolic acid, ubiquinone and / or dolochol.

[0036] According to a further preferred embodiment of the present invention, the polyphenol is a polyhydroxyphenol, preferably a tannin, a suberin or a lignin.

[0037] Tannins include polyhydroxyphenols with ortho-positioned hydroxyl groups, particularly derivatives (esters) of gallic acid (3,4,5-trihydroxybenzoic acid) with glucose and related sugars. Depending on the degree of condensation, tannins can be classified as gallotannins (e.g., glucogallin) or ellagitannins (e.g., pendunculagin). The free hydroxyl groups enable cross-linking with polymers as well as proteins. This allows amino acids or proteins present on the surface of cells and viruses to be absorbed by the PU foam according to the invention. Gases such as oxygen, H2S, and ammonia can also be absorbed by the reactive groups of the bound polyphenols.

[0038] Suberin is a hydrophobic biopolymer embedded in plant cell walls. As a hydrophobic material, suberin has the natural function of sealing roots and preventing water penetration. Lignin comprises a group of macromolecules made up of different monomer building blocks (coumaryl, coniferyl, and sinapy alcohols, etc.). Lignin is characterized by structures based on phenol complexes (phenylpropanoids) with hydroxyl, methoxy, and aryloxy substituents. Lignin is hydrophobic and exhibits particular absorption capacity when it comes to binding polyvalent metal ions (Fe, Mn, Cr, etc.) as well as UV light with wavelengths in the range of 100 to 300 nm.

[0039] By covalently binding a suberin and / or lignin in the PU foam, the material can, for example, acquire hydrophobic, absorptive and / or UV-resistant properties or these properties can be improved.

[0040] According to a further preferred embodiment of the present invention, the tannin is a gallotannin or an ellagitannin.

[0041] According to a further preferred embodiment of the present invention, the polyphenol is selected from the group consisting of phytoalexins, preferably resveratrol, flavonols, preferably taxifols, catechins, flavonoids, anthocyanins, proanthocyanidins, procyanidins, phlobaphenes and isoflavones.

[0042] Phytoalexins, for example, are low-molecular-weight, antimicrobial, and antioxidant organic compounds that can be produced by plants immediately after infection by microorganisms (such as bacteria or fungi) to inhibit their spread, growth, or reproduction within the plant. By binding phytoalexins to PU foam, the material can be given antimicrobial properties.

[0043] According to a further preferred embodiment of the present invention, the at least one secondary plant substance is a tree resin, preferably rosin, mastic or balsam.

[0044] Surprisingly, it has been shown that a significant part of the antibiotic, and especially the antimicrobial, effects of compounds is based not only on various metabolic influences in microorganisms, but also on the adhesive properties of solid resins (such as rosin). The physical spread of microbes can be inhibited or prevented by the covalent bonding of tree resin to PU foam, as the microbes adhere to the resin through adhesive forces.

[0045] PU foams can be divided into closed-cell or partially closed-cell PU rigid foams and open-cell or partially open-cell PU flexible foams. PU rigid foams are primarily used as insulation materials or for thermal insulation in buildings. PU flexible foams are used in a variety of technical applications in industry and in the private sector, e.g. for sound insulation, in the manufacture of mattresses or for upholstering furniture. The automotive industry represents a particularly important market for various types of PU foams, such as conventional flexible foams based on ether or ester polyols, rigid foams and foams with properties that lie between these classifications. Here, rigid foams can be used as headliners, ester foams for the interior trim of doors and for punched-out sun visors, and cold and flexible foams for seating systems.Another particularly important market concerns mattresses and seating systems for living rooms, offices, etc. Regarding flexible foams, a distinction can also be made between cold-cure flexible foams and hot-cure flexible foams.

[0046] According to a further preferred embodiment of the present invention, the PU foam can therefore be a PU rigid foam, a PU flexible foam or a viscoelastic PU foam.

[0047] PU foam can be produced in a variety of ways. In principle, polyurethane is produced by the polyaddition reaction of isocyanate components with polyol components, as described above. To foam the polyurethane resulting from the reaction, blowing agents (e.g., water) can be added to the mixture of isocyanate components with polyol components. The isocyanate components used in the present invention are preferably one or more organic polyisocyanates with two or more isocyanate functions. In general, all known aliphatic, cycloaliphatic, arylaliphatic, and preferably aromatic polyfunctional isocyanates can be used.Examples which can be mentioned here are alkylene diisocyanates with 4 to 12 carbon atoms in the alkylene radical, such as 1,12-dodecane diisocyanate, 2-ethyltetramethylene-1,4-diisocyanate, 2-methylpentamethylene-1,5-diisocyanate, tetramethylene-1,4-diisocyanate, and preferably hexamethylene-1,6-diisocyanate (HMDI), cycloaliphatic diisocyanates such as cyclohexane-1,3- and 1,4-diisocyanate and any mixtures of these isomers, 1-isocyanato-3,35-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI for short), 2,4- and 2,6-hexahydrotoluylene diisocyanate and the corresponding isomer mixtures, and preferably aromatic di- and polyisocyanates, such as 2,4- and 2,6-toluene diisocyanate (TDI) and the corresponding isomer mixtures, methylenedi(phenylisocyanate) (MDI), mixtures of 2,4'- and 2,2'-methylenedi(phenylisocyanate) and polyphenylpolymethylenepolyisocyanates (crude MDI) and mixtures of crude MDI and toluene diisocyanates (TDI).The organic di- and polyisocyanates can be used individually or in mixtures. It is also possible to use isocyanates modified by the incorporation of urethane, uretdione, isocyanurate, allophanate, and other groups, so-called modified isocyanates. Particularly suitable organic polyisocyanates and therefore particularly preferably used are various isomers of toluene diisocyanate (2,4- and 2,6-toluene diisocyanate (TDI), in pure form or as isomer mixtures of different compositions), 4,4'-methylenedi(phenyl isocyanate), the so-called "crude MDI" or "polymeric MDI" (contains not only the 4,4'- but also the 2,4'- and 2,2'-isomers of MDI and higher-nuclear products) as well as the binuclear product known as "pure MDI" consisting predominantly of 2,4'- and 4,4'-isomer mixtures or their prepolymers.

[0048] Polyols suitable as polyol components within the meaning of the present invention are all organic substances having several groups reactive towards isocyanates, preferably OH groups. Preferred polyols are all polyether polyols and / or polyester polyols and / or hydroxyl-containing aliphatic polycarbonates commonly used for the production of polyurethane systems, in particular PU foams, in particular polyether polycarbonate polyols and / or polyols of natural origin, so-called "natural oil-based polyols" (NOPs). Preferably usable polyether polyols can be produced by known processes, e.g. by anionic polymerization of alkylene oxides in the presence of alkali hydroxides, alkyl alcoholates or amines as catalysts and with the addition of at least one starter molecule that preferably contains 2 or 3 reactive hydrogen atoms bonded to them, or by cationic polymerization of alkylene oxides in the presence of Lewis acids such asAntimony pentachloride or boron trifluoride etherate, or by double metal cyanide catalysis. Suitable alkylene oxides contain 2 to 4 carbon atoms in the alkylene radical. Examples are tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide; ethylene oxide and 1,2-propylene oxide are preferably used. The alkylene oxides can be used individually, cumulatively, blockwise, alternating one after the other, or as mixtures. Compounds with at least 2, preferably 2 to 8 hydroxyl groups or with at least two primary amino groups in the molecule are particularly suitable as starting molecules. Starter molecules that can be used are, for example, water, 2-, 3- or 4-hydric alcohols such as ethylene glycol, propanediol-1,2 and -1,3, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, castor oil, etc., higher polyfunctional polyols, in particular sugar compounds such as glucose, sorbitol, mannitol and sucrose, polyhydric phenols, resoles such asoligomeric condensation products of phenol and formaldehyde and Mannich condensates of phenols, formaldehyde and dialkanolamines as well as melamine, or amines such as aniline, EDA, TDA, MDA and PMDA, particularly preferably TDA and PMDA. The choice of a suitable starter molecule depends on the particular field of application of the resulting polyether polyol in polyurethane production (e.g. higher molecular weight triols are used to produce flexible PU foams than in the production of rigid PU foams). Polyester polyols which are preferably used are based on esters of polybasic aliphatic or aromatic carboxylic acids, preferably with 2 to 12 carbon atoms. Examples of aliphatic carboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid and fumaric acid. Examples of aromatic carboxylic acids are phthalic acid, isophthalic acid, terephthalic acid and the isomeric naphthalenedicarboxylic acids.The polyester polyols are obtained by condensation of these polybasic carboxylic acids with polyhydric alcohols, preferably diols or triols having 2 to 12, particularly preferably 2 to 6 carbon atoms, preferably trimethylolpropane and glycerol.

[0049] Preferred polyether polycarbonate polyols are polyols which contain carbon dioxide bound as carbonate. Since carbon dioxide is produced in large quantities as a by-product in many processes in the chemical industry, the use of carbon dioxide as a co-monomer in alkylene oxide polymerizations is of particular commercial interest. Partially replacing alkylene oxides in polyols with carbon dioxide has the potential to significantly reduce the costs of producing polyols. In addition, the use of CO2 as a co-monomer is ecologically very advantageous since this reaction represents the conversion of a greenhouse gas to a polymer. The production of polyether polycarbonate polyols by addition of alkylene oxides and carbon dioxide to H-functional starter substances using catalysts has been known for a long time.

[0050] According to a further preferred embodiment of the present invention, the PU foam is produced on the basis of polyether and / or polyester polyol and toluene-2,4-diisocyanate and / or methylene di(phenyl isocyanate).

[0051] According to a further preferred embodiment of the present invention, the PU foam has open or closed cells. "Open cells" in the context of the present invention means that a foam has good air permeability (= porosity). The air permeability of the foam can be determined by measuring the back pressure on the foam. The back pressure measurement can be carried out in accordance with EN 29053. If the measured back pressure is given in mm water column, open-cell PU foams, in particular flexible PU foams, have a back pressure of preferably less than 100 mm, more preferably < 50 mm water column, determined according to the described measuring method. In the present invention, "closed cells" means a foam that has almost closed cells within the foam material, i.e. cells with only a small opening.Due to the small size of the openings, air flows back in only slowly after compression, resulting in slower recovery. Closed-cell PU foam preferably has a dynamic pressure of at least 300 mm water column.

[0052] The at least one secondary plant substance is bound to the PU foam or "integrated" into it by a covalent bond between the reactive groups of the isocyanate component and the at least one secondary plant substance. In other words, this means that there is not only an adhesive bond or a physical bond between the at least one secondary plant substance and the PU foam or its isocyanate component, but predominantly a chemical, covalent bond. In addition to the secondary plant substances, the PU foam can comprise other substances that modify the properties of the material. These substances can enhance or expand the properties of the PU foam obtained by the secondary plant substances. According to a further preferred embodiment of the present invention, the PU foam therefore comprises light stabilizers, pigments, wood particles, biocidal, acaricidal and / or fungicidal active ingredients.

[0053] In a further preferred embodiment of the present invention, the secondary plant substances are introduced partially or entirely in the form of finely divided plant parts, preferably fine wood particles or wood particles or seeds. The finely divided plant parts can enhance or expand the properties of secondary plant substances which were not introduced by finely divided plant parts. Depending on their origin, the finely divided plant parts can contain a specific high proportion of secondary plant substances. Thus, the finely divided plant parts can be introduced into PU foam for various applications based on their natural composition of secondary plant substances. Preferably, the secondary plant substances can be introduced in the form of wood particles with other secondary plant substances. For example, larch wood with a high diterpenoid content can be produced with the addition of isolated (e.g.extract) oak tannin can be advantageously combined. The finely divided plant parts introduced can have the same origin or be mixtures of finely divided plant parts of different origins. Preferably, the secondary plant substances can be introduced partially or entirely in the form of finely divided plant parts, preferably wood particles, of different origins. In this way, the different natural properties of the introduced secondary plant substances can be combined and utilized. For example, pine wood particles and stone pine wood particles can be introduced in order to combine the naturally occurring secondary plant substances of the wood. Preferably, the secondary plant substances are introduced partially or entirely in the form of fine wood particles or wood particles. The introduced fine wood particles or wood particles are preferably native fine wood particles or wood particles. The term “native wood fines orWood particles", wood fines or wood particles which are in particular not further processed by carbonization, charring or burning. According to a preferred embodiment of the present invention, the wood particles have a particle size of less than 50 pm, preferably less than 40 pm, even more preferably less than 30 pm, even more preferably less than 20 pm, even more preferably from 0.1 pm to 20 pm, even more preferably from 0.5 to 10 pm, even more preferably from 1 pm to 5 pm. Such finely divided wood particles can be produced, for example, by cryogenic grinding, preferably by means of impact mills or colloid mills.

[0054] 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%, even more preferably at least 90%, even more preferably at least 95%, even more preferably at least 99%, in particular 100%, of the wood particles used according to the invention have the above-mentioned particle size. The wood particles can have any shape.

[0055] It has surprisingly been found that the introduction of wood particles which have a particle size of less than 50 pm brings with it a number of advantages. In accordance with its biologically determined structure, wood is structured by means of fibrils and therefore displays a defined longitudinal orientation. This structure essentially serves to maintain the mechanical strength of trees and shrubs. Fibrils consist almost exclusively of cellulose strands which are embedded in a mixture of (unoriented) intercellular substances (such as hemicellulose, lignin). According to the present invention, this specific structure is retained during the production of the wood particles, as mentioned above, since the wood is preferentially split lengthwise, which leads to an undesirable, fibrous longitudinal orientation of the ground material.Microscopic examinations have shown that the longitudinal structure of the fibrils is only permanently broken down when the material is ground to below the fibril diameter (from approximately 0.5 mm to 0.1 mm, depending on the type of wood). This is important because wood particles with a particle size of more than 50 pm have corresponding fibril diameters and are therefore prone to agglomeration / felting. This effect is particularly noticeable when wood particles are mixed with a highly viscous polyol component. Homogenization is therefore only possible with great effort and, due to its batch process, conflicts with the requirements of continuous foaming. Such agglomerates can lead to blockages in the high-pressure mixing chambers and their feed lines, making application disproportionately difficult.It has therefore surprisingly been found that with a particle size of less than 50 pm, preferably less than 30 pm, the agglomeration / felting of the introduced wood particles can be prevented. Furthermore, it has been found that only below a particle size of 50 pm does the desired release of the secondary plant substances into the polyol matrix occur within an acceptable period of time, so that the time required for mixing with isocyanate is sufficient to ensure the desired, inventive, covalent bonding of the secondary plant substances to the PU foam. It has also been found that such fine grinding leads to problems, particularly with elastic coniferous woods (softwood), although satisfactory results can also be achieved by cryogenic grinding using liquid nitrogen or dry ice.Furthermore, this milling method offers the advantage of protecting reactive secondary plant substances from premature degradation, such as oxidation. Preferably, additional additives such as dyes, light stabilizers, UV stabilizers, and even eluates of secondary plant substances from other sources can be added and optimally homogenized during the milling process. Any solvents (including water from wood absorption) can evaporate during this process step and thus do not interfere with the subsequent PU foaming.

[0056] According to a further preferred embodiment of the present 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, thuja 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.

[0057] It has been shown that it is advantageous to adjust the ratio between secondary plant substances and wood particles in order to further emphasize the desired effects.

[0058] A further aspect of the present invention relates to a process for producing the PU foam according to the invention.

[0059] In the inventive production of the PU foam according to the invention, preferably at least one polyol component and at least one isocyanate component are reacted with one another, optionally in the presence of blowing agents and catalysts, with the addition of at least one secondary plant substance. Usable polyol components and isocyanate components according to the present invention have already been described above. Depending on the chain length and number of branches of the polyol component, the mechanical properties of the PU foam can be influenced. It goes without saying that the person skilled in the art will select the necessary amounts of the components accordingly for the production of the various PU foam types, e.g., hot-cure, cold-cure, ester-PU flexible foams or PU rigid foams, in order to obtain the desired polyurethane type, in particular PU foam type.The inventive production of PU foams can be carried out by any process familiar to the person skilled in the art. The inventive process can be carried out continuously or batchwise.

[0060] Any catalysts for the reactions 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 CCh elimination (carbodiimide formation) and / or isocyanate-amine (urea formation) and / or "secondary" crosslinking reactions such as isocyanate-urethane (allophanate formation) and / or isocyanate-urea (biuret formation) and / or isocyanate-carbodiimide (uretonimine formation) can be used as catalysts of the present invention. Suitable amounts of catalyst depend on the type of catalyst.

[0061] Suitable catalysts within the meaning of the present invention are, for example, substances which catalyze one of the aforementioned reactions, in particular the gel reaction (isocyanate-polyol), the blowing reaction (isocyanate-water) and / or the di- or trimerization of the isocyanate. Such catalysts are preferably nitrogen-containing compounds, in particular amines and ammonium salts, and / or metal-containing compounds. Suitable nitrogen-containing compounds as catalysts, hereinafter also referred to as nitrogen-containing catalysts, within the meaning of the present invention are all nitrogen-containing compounds according to the prior art which catalyze one of the above-mentioned isocyanate reactions and / or can be used to produce polyurethanes, in particular polyurethane foams.Suitable metal-containing compounds as catalysts, hereinafter also referred to as metal-containing catalysts, for the purposes of the present invention are all metal-containing compounds according to the prior art which catalyze one of the above-mentioned isocyanate reactions and / or can be used to produce polyurethanes, in particular polyurethane foams. They can be selected, for example, from the group of organometallic or organometallic compounds, organometallic or organometallic salts, organic metal salts, inorganic metal salts and from the group of charged or uncharged metal-containing coordination compounds, in particular metal chelate complexes.

[0062] Suitable propellants for the purposes of this invention are gases, e.g. liquefied CO2, and highly volatile liquids, e.g. hydrocarbons with 4 or 5 carbon atoms, preferably cyclo-, iso- and n-pentane, - provided they are not ozone-depleting - fluorocarbons, preferably HEG 245fa, HEG 134a and HEG 365mfc, but also olefinic fluorocarbons such as HFO 1233zd or HFO1336mz zZ, chlorofluorocarbons, preferably HCFC 141b, oxygen-containing compounds such as methyl formate and dimethoxymethane. In addition to physical propellants, other chemical propellants which react with isocyanates to evolve gas, such as e.g. Formic acid, carbamates, or carbonates can be used. For open-cell PU flexible foams, water is preferably used as a blowing agent.

[0063] According to a further preferred embodiment of the present invention, the at least one secondary plant substance is added in the form of an extract or eluate.

[0064] Secondary plant substances can be obtained by methods such as steam distillation, extraction, or chromatography. For example, young plants typically yield terpenoid hydrocarbons, and older plants increasingly yield oxygen-containing derivatives such as alcohols, aldehydes, and ketones. Methods for obtaining secondary plant substances are known from the prior art. For the purposes of the present invention, the term "extract" refers to extracts of solid, liquid, and / or oily nature from plants, in particular their fruits, roots, rhizomes, stems, shoots, leaves, kernels, or seeds, which have been obtained by extraction.In the present invention, "eluate" is understood to mean a solid, liquid and / or oily substance removed or dissolved from plants, in particular their fruits, roots, rhizomes, stems, shoots, leaves, kernels or seeds, which were obtained by chromatographic separation processes.

[0065] One advantage of using extracts and eluates is the natural composition of the components of the secondary plant substances they contain. A particular advantage is that the bioavailability of the secondary plant substances contained in extracts can be higher than when using synthetic compounds.

[0066] A further advantage of using eluates is their better dispersibility in the polyol component, since terpenoids, for example, are readily soluble in the polyol component at the preferred amounts. During the polyaddition with isocyanate, a particularly pronounced, even distribution occurs in the foam and thus also on the accessible cell surfaces.

[0067] According to a particularly preferred embodiment of the present invention, the at least one secondary plant substance is added to the at least one polyol component.

[0068] The at least one secondary plant substance is capable of forming covalent bonds with the reactive groups of the isocyanate component. Therefore, it is advantageous for the at least one secondary plant substance to be added to the at least one polyol component in order to prevent a premature reaction between the isocyanate component and the at least one secondary plant substance. According to a further preferred embodiment of the present invention, the PU foam is used for the production of filters, upholstery, mattresses, pillows, hygiene articles, cleaning sponges, and / or insulating layers, preferably in textiles, sound insulation, or thermal insulation.

[0069] For example, the absorption properties of foams play an important role in a number of applications. It is important that the foam has a high moisture absorption capacity with subsequent rapid release of the absorbed, stored moisture. The present invention enables the use of a modified PU foam with increased absorption properties for absorbing, for example, body fluids such as sweat, blood, or urine. These properties make such PU foams suitable for use in bandages.

[0070] Another application includes protection against microbes by absorbing and / or eliminating germs on filter materials, upholstery, mattresses, pillows, hygiene articles, medical devices, cleaning products or insulating layers. Antimicrobial substances are widely used in everyday life to prevent the spread of microbes and microbial infections, e.g. in healthcare, the food industry, agriculture or in common household products. However, a major problem resulting from the extensive use of such substances is the constant contamination of the environment by fungicidal and / or bactericidal substances. Such contamination can ultimately lead to the emergence of antibiotic-resistant strains of microbes.By applying the present invention, a physical absorption of bacteria, viruses, molds and / or their spores on PU foam is a great advantage because it prevents the use of physiologically and ecologically harmful fungicides and antibiotics.

[0071] EXAMPLES In Examples 1 to 4, an open-cell flexible foam was produced according to the state of the art, using propylene oxide polyether polyol (functionality 3, MW 3500, OH number 50), isocyanate (toluene-2,4-diisocyanate (TDI) 80 / 20, NCO index 105), and blowing agent (water / TDI). The density of the produced PU foam was 45-50 kg / m³. 3 .

[0072] Example 1 :

[0073] Before foaming (mixing with isocyanate), 6 wt% micronized pinewood (fineness D50=15 pm), 0.7 wt% ellagitannin from French Limousine oak (Quercus robur) and 0.1 wt% perillic acid were homogeneously added to the polyol batch (wt% refers to the total formulation of the foam).

[0074] The obtained yellow / orange PU flexible foam showed: a) fungicidal properties (tested according to DIN EN 14119) b) inhibition of the fertility of house dust mite eggs by more than 95% c) antiviral activity in an in vitro test according to ISO 18184.

[0075] Due to the properties found on this product, this PU soft foam is suitable for use as a filter, in mouth-nose masks or as upholstery material (bedroom and / or living room).

[0076] Example 2:

[0077] Analogous to example 1, in this example 3 wt% micronized larch wood (D50=5 to 10 pm), 1.5 wt% mastic, 0.5 wt% thyme oil as eluate from Thymus vulgaris (ingredients including: carvacrol, thymol, cymene, geraniol as well as flavones and tannins as polyphenols) and 0.3 wt% HALS1 UV stabilizer (Lowilite 77) were added to the polyol batch to avoid discoloration.

[0078] The obtained PU flexible foam showed: a) bactericidal properties (DIN EN ISO 20743) b) anti-inflammatory properties.

[0079] Due to the properties found on this product, this PU soft foam is suitable for use as a wound dressing, in dressing material and in mattresses.

[0080] Example 3: Analogous to Example 1, in this example 2.5 wt% lignin, 0.5 wt% tannin (ellagitnannin from oak), 1.5 wt% eluate from pine wood and eucalyptus in a ratio of 1:1 and 0.2 wt% perillic acid were added to the polyol batch.

[0081] The obtained PU flexible foam showed: a) bactericidal properties (DIN EN ISO 20743) b) fungicidal properties (tested with DIN EN 14119) .

[0082] Due to the properties found on this product, this PU soft foam is suitable for use as a filter, in masks, wound dressings and in mattresses.

[0083] Example 4:

[0084] Analogous to Example 1, in this example, 2 wt% rosin from Nordic pine, 0.5 wt% eluate from sage, rosemary and ivy in the ratio 2:1:1 (contained among other things oleanolic acid), 0.3 wt% cineole from eucalyptus oil and 0.3 wt% HALSl UV stabilizer (Lowilite 77) were added to the polyol batch to avoid discoloration.

[0085] The obtained PU flexible foam showed: a) bactericidal properties (DIN EN ISO 20743) b) fungicidal properties (tested with DIN EN 14119) c) acaricidal properties, in particular through physical bonding effect on mites and their eggs.

[0086] Due to the properties found on this product, this PU soft foam is suitable for use in mattresses and furniture upholstery, filters, especially fine dust filters in vacuum cleaners, and general hygiene applications.

[0087] Example 5:

[0088] In this example, a closed-cell rigid foam was manufactured according to state-of-the-art technology. It was produced with propylene oxide polyether polyol (functionality 6, MW 450, OH number 50), isocyanate (methylene diphenyl isocyanate (MDI) 29% NGO, NCO index 110), and blowing agent (cyclopentane). The PU foam had a density of 35-40 kg / m³. 3 on.

[0089] Before foaming (mixing with isocyanate), 4 wt% lignin, 2 wt% tannin (ellagitannin from oak), 0.2 wt% perillic acid and 0.3 wt% HALSl UV stabilizer (Lowilite 77) were added to the polyol.

[0090] The resulting rigid PU foam exhibited particularly fine pores due to the addition of lignin, which served as a pore nucleating agent. The foam demonstrated excellent resistance to mold infestation (Aspergillus niger), making it particularly suitable for use as an insulating material in residential construction.

[0091] Example 6: Eluation test

[0092] The foams of Examples 1 to 5 showed no leaching effects in an elution test with distilled water (pH 7), which indicates the covalent bonding of the additives.

Claims

CLAIMS 1. PU foam comprising at least one secondary plant substance bound thereto, wherein the at least one secondary plant substance is present partly or entirely in the form of wood particles.

2. PU foam according to claim 1, characterized in that the PU foam comprises 0.1 to 10 wt%, preferably 0.2 to 5 wt%, particularly preferably 0.3 to 3 wt%, of the at least one secondary plant substance.

3. PU foam according to claim 1 or 2, characterized in that the at least one secondary plant substance is a terpenoid or a polyphenol.

4. PU foam according to claim 3, characterized in that the terpenoid is a monocyclic or polycyclic terpenoid, preferably a bicyclic, tricyclic, tetracyclic or pentacyclic terpenoid.

5. PU foam according to claim 3 or 4, characterized in that the terpenoid is a monoterpenoid selected from the group consisting of pyrethrin, thymol, cineole, thujanol, perillic acid, linalool, myrcenol, citral, citronellal, geranic acid, junione, chrysanthemol, menthol, terpineol, verbenol, carveol, piperitone and camphor, preferably pyrethrin, thymol, cineole, thujanol and / or perillic acid.

6. PU foam according to one of claims 3 to 4, characterized in that the terpenoid is a sesquiterpenoid selected from the group consisting of farnesin, bisabolol, armillarin, merulidial, hirsutic acid, nerolidol, zingiberene, germacrane, periplanon, elemol, gua an and cedrane, preferably farnesin, bisabolol, armillarin, merulidial and / or hirsutic acid. I. PU foam according to one of claims 3 to 4, characterized in that the terpenoid is a diterpenoid selected from the group consisting of agelasin, larixol, dehydroabietinol, abietic acid, bolegrevilol, aframodial, phytol, retinol, primarane, nimbiol, forskolin, labdanolic acid, cassaic acid, gibberelan, isopimaric acid, dehydroabietinol and abietic acid, preferably agelasin, larixol, dehydroabietinol, abietic acid, bolegrevilol and / or aframodial.

8. PU foam according to one of claims 3 to 4, characterized in that the terpenoid is a sesterpenoid selected from the group consisting of ircinin, neomanoalid, cericeran and dehydroircinin.

9. PU foam according to one of claims 3 to 4, characterized in that the terpenoid is a triterpenoid selected from the group consisting of limonoids, lanosterol, fusidan, fusidic acid, euphan, dammarane, cucurbitan, cucurbitacin, betulin and betulinic acid.

10. PU foam according to one of claims 3 to 4, characterized in that the terpenoid is a tetraterpenoid selected from the group consisting of carotene, crocetin and lycopene. II. PU foam according to one of claims 3 to 4, characterized in that the terpenoid is a polyterpenoid selected from the group consisting of betulaprenol, oleanolic acid, ubiquinone, dolochol and betulaprenols, preferably betulaprenol, oleanolic acid, ubiquinone and / or dolochol.

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

13. PU foam according to claim 12, characterized in that the tannin is a gallotannin or an ellagitannin.

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

15. PU foam according to one of claims 1 to 14, characterized in that the at least one secondary plant substance is a tree resin, preferably rosin, mastic or balsam.

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

17. PU foam according to one of claims 1 to 16, characterized in that the PU foam is produced on the basis of polyether and / or polyester polyol and toluene-2,4-diisocyanate and / or methylene di(phenyl isocyanate).

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

19. PU foam according to one of claims 1 to 18, characterized in that the PU foam comprises light stabilizers, pigments, biocidal, acaricidal and / or fungicidal active ingredients.

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

21. PU foam according to 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, thuja 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.

22. A process for producing PU foam according to any one of claims 1 to 21, comprising the step 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 which catalyzes the isocyanate-polyol reactions, wherein at least one secondary plant substance is added during the reaction of the at least one polyol component with the at least one isocyanate component, wherein the at least one secondary plant substance is present partly or entirely in the form of wood particles.

23. The method according to claim 22, characterized in that the at least one secondary plant substance is added in the form of an extract or eluate if the at least one secondary plant substance is present in part in the form of wood particles.

24. The method according to claim 22 or 23, characterized in that the at least one secondary plant substance is added to the at least one polyol component.

25. PU foam obtainable by a process according to any one of claims 22 to 24.

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