Polymer composites containing micronized feldspar.

Abstract

The present invention relates to a polymer composite material comprising: a. a biodegradable polymer in an amount of 1 to 98% by weight of the total weight; b. micronized feldspar in an amount of at least 1% by weight of the total weight; c. a starch and / or protein-containing material in an amount of at least 1% by weight of the total weight; d. optional additives; and e. an optional plasticizer for the starch and / or protein-containing material in an amount of less than 5% by weight of the starch and / or protein-containing material.

Description

[Technical Field]

[0001] The present invention relates to polymer composites containing micronized feldspar. [Background technology]

[0002] The use of starch and / or protein-containing natural materials in biocomposite resins is well known.

[0003] When starch and / or protein containing materials are incorporated into plastics, they generally need to be plasticized to prevent the starch / protein molecules from agglomerating under heat treatment, thus reducing their processability.

[0004] As stated in Yachuan Zhang and Curtis Rempel (2012), "Retrogradation and Antiplasticization of Thermoplastic Starch," Thermoplastic Elastomers, Prof. Adel El-Sonbati (Ed.), ISBN: 978-953-51-0346-2, "The role of plasticizers is to attract surrounding water molecules, reduce the intermolecular interactions between starch molecules, and then increase the flexibility of native starch."

[0005] The paper also states that "three theories have been proposed to explain the mechanism of plasticization." These are the lubrication theory, the gel theory, and the free volume theory. The lubrication theory proposes that plasticizers act as lubricants, smoothing the movement of macromolecules relative to one another. The gel theory proposes that plasticizers disrupt the interactions of starch chain bonds. The free volume theory proposes that plasticizers increase the free volume between starch chains, lowering their glass transition temperature (Tg). The commonality between these theories is that plasticizers are thought to intercalate themselves between starch chains, reducing the forces holding the chains together.

[0006] Several studies have concluded that at least 20% by weight of plasticizer in starch is required to achieve successful plasticization, with most concluding that a level of 30% by weight of plasticizer content is ideal.

[0007] However, it is important to understand that plasticizers for starch / protein-containing materials are distinctly different from those used for biodegradable polymers, which are also similar components in the construction of biocomposite resins. While these types of plasticizers (for biodegradable polymers) are commonly (but not exclusively) alkyl citrates, plasticizers for starch / protein-containing materials are usually (but not exclusively) multifunctional alcohols or polyols, although two plasticizers that have benefits for both materials are polyethylene glycol and polyvinyl alcohol.

[0008] Glycerin / glycerol is the most common plasticizer used to plasticize starch / protein-containing materials because this liquid (at room temperature) provides good elongation but low tensile strength, which is suitable for film applications and the low tensile strength can be compensated for by incorporating high tensile strength biopolymers, whereas solid (at room temperature) plasticizers such as sorbitol provide good tensile strength but lower elongation (Bioresource Technology 2009, 100, 3076-3081).

[0009] Alternatively, the natural sugars in materials such as apple flour and grape pomace can also have a plasticizing effect, and therefore these materials do not require the addition of plasticizers (BioResources 2019, 14, 3210-3230).

[0010] It is generally accepted that the use of plasticizers for starch / protein-containing materials is essential for the successful manufacture of biocomposite resins constructed using biodegradable polymers, which may or may not themselves contain plasticizers targeted to their specific processing requirements.

[0011] The use of mineral fillers is also well known in all plastics and has been particularly incorporated as a component of biocomposite resins including glycerin / glycerol plasticized starch / protein-containing materials to improve strength and stiffness for stiffer article applications.

[0012] Common mineral fillers include calcium carbonate (chalk), clay (talc), and silicon dioxide / titania dioxide, which, when incorporated into biodegradable polymers, provide white pigmentation, reduced cost, and increased biodegradability (e.g., Journal of Applied Polymer Science 2020, 137, 48939 (9 pages)).

[0013] Feldspar minerals with compositions ranging between NaAlSi3O8 and KAlSi3O8 are known as alkali feldspars. They include albite (NaAlSi3O8), moonstone ((Na,K)AlSi3O8), borosilicate ((K,Na)AlSi3O8), orthoclase (KAlSi3O8), and microcline (KAlSi3O8).

[0014] Nepheline syenite is a naturally occurring silica-deficient sodium-potassium aluminosilicate (composed primarily of nepheline and alkali feldspar) that may contain less than one-tenth of crystalline silicon dioxide.

[0015] A commercial use of nepheline syenite powder is as a functional filler and extender for paints, coatings, adhesives, sealants, and inks. This is made possible by its Mohs hardness of 6, compared to half that for calcium carbonate (chalk), 1 for clay (talc), or 1.5-2 for bentonite clay.

[0016] Micronized nepheline syenite (D 50 <10 micrometers) is 1 to 5 m 2 / g surface area and an oil absorption capacity of 20-30 g / 100 g. Furthermore, nepheline syenite is chemically alkaline (pH about 10).

[0017] Nepheline syenite is also used as both a flux and a white pigment in ceramics.

[0018] Nepheline syenite is listed as a polymer additive in Table 1 of Annex 1 of Commission Regulation (EU) No 10 / 2011 on plastic materials and articles intended to come into contact with food (FCM substance number 684).

[0019] The use of feldspar in whole thermoplastics is limited to a few applications such as anti-blocking in polyolefin films and light and heat management in agricultural films due to its high Mohs hardness.

[0020] U.S. Patent No. 9,085,671 lists either nepheline syenite or feldspar as a partial or complete replacement filler for natural wood flour in plastics used as engineered wood products in the form of decks, fences, and architectural trim.

[0021] The object of the present invention is to find a solution to improve the processability and biodegradability of the overall biocomposite resin without losing strength or flexibility. Furthermore, the object of the present invention is to find a polymer composite that is biodegradable yet strong enough to form disposable articles with wall thicknesses greater than 250 micrometers, such as coffee capsules, cutlery, straws, drink stirrers, food trays, single-serving packages such as cups, caps, containers and / or lids, or any other single-use item. [Prior art documents] [Patent documents]

[0022] [Patent Document 1] U.S. Patent No. 9,085,671 [Non-patent literature]

[0023] [Non-Patent Document 1] Yachuan Zhang and Curtis Rempel(2012),Retrogradation and Antiplasticization of Thermoplastic Starch,Thermoplastic Elastomers,Prof.Adel El-Sonbati(Ed.),ISBN:978-953-51-0346-2 [Non-patent document 2] Bioresource Technology 2009,100,3076-3081 [Non-patent document 3] BioResources 2019,14,3210-3230 [Non-patent document 4] Journal of Applied Polymer Science 2020,137,48939(9pages) Summary of the Invention

[0024] 2. The polymer composite material of claim 1, a. a biodegradable polymer in an amount of 1 to 98% by weight of the total weight; b. finely divided feldspar in an amount of at least 1% by weight of the total weight; c. a starch- and / or protein-containing material in an amount of at least 1% by weight of the total weight; d. optional additives; A polymer composite material is provided, comprising: Methods for preparing the polymer composite materials, intermediates for preparing the polymer composite materials, and articles comprising the polymer composite materials are also provided. DETAILED DESCRIPTION OF THE INVENTION

[0025] It has been found that by adding at least 1 wt. % of finely divided feldspar, optionally with suitable additives, there is a favorable attraction between the alkaline (approximately pH 10) nepheline syenite and the slightly acidic (pH = 4-7) carbohydrate (including starch) / protein material, which reduces aggregation of the starch / protein molecules, thereby allowing for better processability and aiding in the biodegradability of the overall biocomposite resin.

[0026] In fact, in one embodiment, nepheline syenite (pH>7) and polyols (having a pH<7), or any other acidic plasticizers added separately to improve processing of starch / protein-containing materials, are not used in combination with each other in a single pass process because under the thermal extrusion process, these two components may react and potentially form a highly viscous chewing-gum type mass that may interfere with the operation of the extruder / compounder.

[0027] Another advantage of the combination of micronized nepheline syenite powder with starch- and / or protein-containing natural products in the absence of any polyol plasticizers relates to their high water solubility. It has been found that the combinations in the absence of polyol plasticizers exhibit significantly lower overall migration amounts under processing from the simulants (A-D1) listed in Table 1 of Annex III of Commission Regulation (EU) No 10 / 2011 on plastic materials and articles intended to come into contact with food.

[0028] For comparison, urea was examined as a plasticizer in extrusion-formed thermoplastic sugar beet pulp film strips in Bioresource Technology 2009, 100, 3076-3081. While not specifically tested because it is a basic molecule (per Bronsted-Lowry acid-base theory), it was further examined for its hydrogen-bonding capabilities, as were many other polyols. The results showed that urea "gave higher ultimate tensile stresses than glycerol for comparable strains to break." In contrast, ethanolamine, diethanolamine, and triethanolamine (all Bronsted-Lowry bases) gave lower results than glycerol. The thermoplastic sugar beet pulp was not incorporated into other plastics, and no mineral fillers were used. Additionally, for a review of the hydrogen bonding properties of urea and its use as a plasticizer for starch, see Yachuan Zhang and Curtis Rempel (2012), Retrogradation and Antiplasticization of Thermoplastic Starch, Thermoplastic Elastomers, Prof. Adel El-Sonbati (Ed.), ISBN: 978-953-51-0346-2.

[0029] U.S. Patent No. 4,242,251 covers the use of feldspar minerals coated with small molecule acids for use as fillers in plastics. In this patent, mineral particles are treated with small molecule acids so that "strong bonds can be formed between the acid on the surface of the mineral particles and metal ions." Thus, the interaction is not acid / base in nature, but rather the formal chemical formation of a metal coordination complex.

[0030] The hardness of nepheline syenite further aids the strength of the biocomposite resin than chalk or talc fillers.

[0031] Unprocessed (or processed but not highly refined) carbohydrate / protein-containing natural materials can have a beneficial plasticizing effect on polymers, but also contain oils that can cause processing problems by leaving char on thermoforming equipment. The oil-absorbing properties of nepheline syenite have also been found to be advantageous in this regard, helping to reduce migration and burning of natural oils.

[0032] US Patent Application Publication No. 2010 / 0003431 lists both feldspar and nepheline syenite as fillers in a plastic layer bonded to a fiber-containing layer in which the listed fibers are derived from natural sources.

[0033] Another common component in the formulation of biocomposite resins is the use of compatibilizers. These materials are designed to improve the surface attraction of hydrophilic components, such as natural and mineral fillers, and hydrophobic biopolymers. They can also be used to blend immiscible polymers (Advances in Polymer Technology 1992, 11, 249-262).

[0034] A common type of compatibilizer is a maleic anhydride-grafted variant of one of the biopolymers used in biocomposite resin formulations, such as maleic anhydride-grafted polylactide resin with polylactide resin (e.g., Composite Interfaces 2018, 25, 515-538) or maleic anhydride-grafted poly(butylene succinate) with poly(butylene succinate) resin (e.g., Waste and Biomass Valorization 2020, 11, 3775-3787).

[0035] Other chemicals that can be grafted onto biopolymers to create compatibilizers include derivatives such as acrylic or methacrylic acid, acrylate derivatives such as butyl acrylate, methacrylate derivatives such as glycidyl methacrylate, maleimide and its derivatives, and itaconic acid and its derivatives.

[0036] Another type of compatibilizer is poly(2-ethyl-2-oxazoline) (see, for example, US Pat. No. 6,632,925).

[0037] In one embodiment, the plasticizer of the starch and / or protein containing material is at most 40% by weight of the starch and / or protein containing material, preferably at most 35%, more preferably at most 30%, even more preferably at most 20%, even more preferably at most 10%, even more preferably at most 5%, even more preferably at most 4%, and most preferably at most 3%, such as at most 1% or at most 0.5% by weight. In one embodiment, the term "at most" is replaced with the term "less than".

[0038] Biocomposite resins have three essential component types: biopolymers, starch / protein-containing materials, and feldspars, with an additive as a fourth option.

[0039] In one embodiment, the biodegradable biopolymer is provided in an amount of 5-80% by weight of the total weight, preferably 10-60% by weight, more preferably 15-40% by weight, even more preferably 20-35% by weight, for example 30% by weight.

[0040] In one embodiment, the micronized feldspar is provided in an amount of 10 to 80% by weight of the total weight, preferably 15 to 60% by weight, more preferably 20 to 50% by weight, even more preferably 25 to 40% by weight, for example 5 to 35% by weight.

[0041] In one embodiment, the starch and / or protein containing material is provided in an amount of 10-80% by weight of the total weight, preferably 15-60% by weight, more preferably 20-50% by weight, even more preferably 25-40% by weight, for example 35% by weight.

[0042] biopolymers The biopolymer may be produced directly from renewable resources or from oil-based sources. Desirably, the biopolymer is a homopolymer, block copolymer, graft copolymer, or random copolymer. Preferably, the biopolymer comprises one or more repeating units or combinations thereof comprising a hydrolyzable bond, such as one or more units selected from the group comprising glycolic acid (e.g., a dimer of glycolic acid, glycolide), lactic acid (e.g., a dimer of lactic acid, lactide), hydroxyalkanoic acids such as hydroxybutyric acid and hydroxyvaleric acid, caprolactone, p-dioxanone, trimethylene carbonate, butylene succinate, butylene adipate, monosaccharides such as hexose, glucose, fructose, and galactose, and pentoses such as ribose and deoxyribose, dicarboxylic acid anhydrides such as sebacic acid and hexadecanedioic acid anhydride, enantiomers thereof such as L-lactic acid or D-lactic acid, esters of sugars such as cellulose acetate, and combinations thereof.

[0043] Typically, the biopolymers are poly(lactic acid) (PLA), DL-polylactide (DLPLA), D-polylactide (DPLA), L-polylactide (LPLA), polyglycolide (PGA), poly(DL-lactide-co-glycolide) (PGLA), poly(ethylene glycol-co-lactide), polycaprolactone (PCL), poly(L-lactide-co-caprolactone-co-glycolide), poly(dioxanone) (PDO), poly(trimethylene carbonate), polyglyconate (e.g., copolymer of glycolide and trimethylene carbonate), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyhydroxybutyrate-co-hydroxyvalerate (PHBV), polyhydroxyvalerate ( The polymers include polymers selected from the group consisting of PHV), polysaccharides (e.g., homopolysaccharides and heteropolysaccharides), modified polysaccharides such as cellulose acetate and chitosan, aliphatic and aromatic copolyesters, poly(1,4-butylene succinate) (PBS), poly(1,4-butylene adipate) (PBA), (polybutadiene adipate-co-terephthalate polymer (PBAT), poly(butylene succinate adipate) (PBSA), polyanhydrides such as poly(sebacic acid-co-hexadecanedioic anhydride) (poly(SA-HDA anhydride)), polyorthoesters (POE), plasticized starch including poly(caprolactone), starch-based aliphatic polyesters, polyesteramides (PEA), and any combination or blend of copolymers thereof.

[0044] In one embodiment, the biopolymer preferably comprises one or more biologically produced polymers, preferably polymers selected from the group including bacterial polyester polyhydroxyalkanoates (PHAs), such as homopolymers and copolymers of 3-hydroxybutyric acid and 3-hydroxyvaleric acid, and poly(lactic acid) / polylactide resins (PLA), and combinations thereof.

[0045] The biopolymers generally have an average molecular weight of more than 500 g / mol, preferably more than 1000 g / mol.

[0046] Preferably, the biopolymer contains little water, for example less than 1% water by weight, preferably less than 0.5% water by weight, based on the total amount of biopolymer.

[0047] Starch / Protein-containing materials Suitable natural materials include flour, ground expeller / meal / cake, ground pomace, ground distillers' grains, ground brewer's grains (or brewer's grains / powder), ground biscuit meal (or biscuit cereal meal), coffee grounds, cocoa bean shells, or combinations thereof.

[0048] The term "flour" generally refers to a composition having both a starch-containing fraction and a protein-containing fraction derived from the same plant source, without the starch-containing fraction and the protein-containing fraction being separated from each other. Typical proteins present in flour are globulins, albumins, glutenins, secalins, prolamins, and glutelins. Other components derived from plant sources, such as cell walls or non-starch polysaccharides, fiber, lipids, and ash, may also be present. The flour may be subjected to any treatment, such as enzymatic treatment, with the treated components being introduced together. The flour can be used completely without generating waste.

[0049] Flours are derived from seeds, tubers, roots, grains or grasses. More broadly, flours can be derived from seeds, legumes, nuts and grains such as beans, kidney beans, soybeans, lentils, (yellow, green, wrinkled) peas, chickpeas, lupins, wheat, buckwheat, triticale, millet (sorghum), canary seed, amaranth grain, maize, sago, barley, oats and rice. Furthermore, flours can be derived from grasses, roots or tubers such as potato, sweet potato, quinoa, arrowroot and cassava (tapioca). Flours can be derived from amylose-rich (non-glutinous) or amylopectin-rich (waxy) plant sources.

[0050] Flour can be made from the whole grain (groat) or the seed, including the hull and / or husk. As used herein, the definition of grain includes the groat, which is the dehulled kernel of the cereal kernel, including the cereal germ and fiber-rich bran portion of the kernel, as well as the endosperm.

[0051] Chemically modified flours or flour derivatives, including purified / separated starches, may also be used. Preferably, non-chemically modified or slightly chemically modified, preferably phosphorylated, flours are used.

[0052] The flour preferably contains 60 to 95% by weight of carbohydrates, e.g., starch, sugars or non-starch polysaccharides such as pentosans, based on the total mass of the flour, and generally has an average molecular weight of more than 500 g / mol, preferably more than 1000 g / mol.

[0053] Expeller / meal / cake is the residue from processed oilseeds, which are primarily grown for the extraction of edible oils, but can also include seeds grown for the purpose of oil extraction for any use, such as fragrance and personal care. Whole oilseeds contain high concentrations of energy and moderate concentrations of protein and fiber. The main oilseeds include soybean, rapeseed (canola), sunflower, and palm oil.

[0054] The processes utilized for the extraction of oil from oilseeds (oilseed defatting) essentially fall into three categories: solvent extraction, hot pressing (or expeller extraction), and cold pressing. Solvent extraction is typically performed after mechanical crushing of the oilseeds (industrially) using hexane, removing 97-99% of the oil content, typically expected to result in an oil content of less than 1.5%. Press extraction is performed mechanically by physical squeezing of the oil from the oilseeds using a cold press performed at less than 60°C / 140°F. Hot pressing / expeller extraction involves heat pretreatment of the oilseeds before pressing. The expected oil content from pressing is typically less than 95%.

[0055] The residue of oil seeds after oil extraction is commonly referred to as meal, expeller, or cake (press cake). More precisely, solvent extracted oil seeds result in meal, hot press extraction results in expeller meal, and cold press extraction results in expeller cake. For purposes of this patent, meal is defined as the material resulting from the solvent extraction process that contains less than 3% oil, preferably 1.5 w / w or less. For example, solvent extracted rapeseed meal should not contain more than 2-3% oil (see, e.g., https: / / www.feedipedia.org / node / 52, incorporated herein by reference).

[0056] Oilseed meal is the major source of protein in livestock diets, with protein levels typically exceeding 20%. Examples of commercial meals include, but are not limited to, soybean meal or soybean meal, palm meal or palm kernel meal, coconut meal or copra meal, sunflower meal, peanut meal or groundnut meal, cottonseed meal, rapeseed meal or oilseed rape meal or canola meal, castor bean meal, flaxseed meal, linseed seed meal or linseed meal, safflower meal, camelina meal, corozo palm nut meal or corozo meal, grape seed meal, jatropha kernel meal, mustard seed meal, corn germ meal, sal seed meal or Shorea Robusta seed meal, sesame seed meal, hemp seed meal, tobacco seed meal, watermelon seed meal, niger seed meal, rice bran meal, wheat germ meal, borage meal, black currant meal, evening primrose meal, rosehip meal, e.g., Buglossoides arvensis arvensis (ahiflower) meal, jojoba meal, and almond meal.

[0057] Pomace or marc is the name given to the solid residue of fruit or vegetable juices or oils after pressing to remove the juice or oil. Common fruits known for producing pomace include grapes, olives, blackcurrants, oranges, pineapples, and apples. Pomace typically contains the peel, pulp, seeds, and stems of the fruit. Pomace can also be produced as a by-product of vegetable juice or oil processing, such as carrots and beetroots. Fruit pomace typically contains 20-50% w / w of the original fruit mass, while vegetable pomace typically contains more than 30% w / w of the original vegetable mass.

[0058] While distillers' spent grains are a cereal by-product of the fermentation or distillation process, brewer's spent grains or spent grains usually specifically refer to residual barley (in a mixture with other cereal grains or grain products) produced as a by-product of beer brewing collected prior to fermentation of the wort. Most brewers' spent grains contain barley malt kernel husks in combination with portions of the barley pericarp and seed coat layers. Distillers' spent grains are usually a mixture of corn, rice, and other grains derived from either brewing or ethanol biofuel production. For purposes of this patent, the use of the term spent grain encompasses distillers' spent grains and spent grains.

[0059] Distillers' grains are available as wet distillers' grains, which contain primarily unfermented grain residue (protein, fiber, fat, and up to 70% moisture), and as dried distillers' grains with solubles, which are obtained by drying concentrated thin stillage to 10-12% moisture or less. Dried distillers' grains are a complex composition of protein (26.8-33.7% dry weight), carbohydrates (39.2-61.9%), oil (3.5-12.8%), and ash (2.0-9.8%). The grains definition refers to dried distillers' grains and / or dried brewer's grains, optionally further solvent-treated to remove solubles and / or oils.

[0060] Biscuit meal or biscuit cereal meal may comprise either a mixture of crumb waste or individual components of cooked and processed biscuits, cakes and cereal foods.

[0061] Coffee grounds are the remaining kernels of coffee brewing, from which the solubles have been extracted by treatment with boiling water. The wet coffee grounds are then conditioned, dried, and classified to create a dry powder. Coffee grounds contain primarily carbohydrates (45%), alkaloids (17%), lignin (14%), lipids (11%), and protein (10%).

[0062] Cocoa shells (or cocoa bean shells) are the shells (or husks) that are separated from cocoa beans during the roasting process. Cocoa shells are rich in dietary fiber, protein, and polyphenols.

[0063] It is expressly noted here that preferably the starch and / or protein in the starch and / or protein-containing material is not surface-modified, as this would chemically alter the surface properties and undesirably change the nature of the interaction with the micronized feldspar, making it more hydrophobic and more easily mixable with the biopolymer.

[0064] feldspar Feldspars are a group of rock-forming aluminum tectosilicate minerals that also contain other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are plagioclase (sodium-calcium) feldspars and alkali (potassium-sodium) feldspars (called alkaline because of their alkali metal rather than their pH range).

[0065] Feldspar compositions lie in the ternary phase diagram between potassium feldspar (KAlSi3O8) - albite (NaAlSi3O8) - anorthite (CaAl2Si2O8). Barium feldspar forms as a result of the substitution of barium for potassium in the mineral structure.

[0066] The preferred form in this embodiment is nepheline syenite because of the absence of crystalline silica (quartz), its low refractive index (approximately 1.5) similar to polylactide resin, and its transparency to UV radiation aids in the biodegradation of the biopolymer.

[0067] It is expressly noted here that preferably the micronized feldspar is not surface-modified, as this would chemically alter the surface properties and undesirably change the nature of the interaction with starch and / or proteins in the starch- and / or protein-containing material, making it more hydrophobic and more easily mixable with the biopolymer.

[0068] additives Optional additives include plasticizers for biopolymers, such as citric acid esters (e.g., acetyltributyl citrate, acetyltriethyl citrate, tributyl citrate, or triethyl citrate), substituted adipates (e.g., di(2-ethylhexyl) adipate, dihexyl adipate, dioctyl adipate), substituted sebacic acid esters (e.g., dibutyl sebacate), and oligomeric lactic acid (OLA). Vegetable oils, such as epoxidized soybean oil and epoxidized linseed oil, or epoxidized vegetable oils, are natural plasticizers for biopolymers (e.g., U.S. Pat. No. 10,590,261). Optional additives may further include additives known in the art, such as compatibilizers, antioxidants, lubricants, dyes, pigments, fragrances, odorants, liquid or gas absorbers, small molecule absorbers, flame retardants, oxygen and / or water vapor barrier additives, ultraviolet absorbers or stabilizers, heat stabilizers, infrared absorbers or screeners, melt flow promoters, impact modifiers, nucleating agents, surfactants, chelating agents, coupling agents, adhesives, primers, reinforcing agents, inert fillers, fungicides, herbicides, fertilizers and opacifiers, compounds with rodent repellent effects, and waxes, and ideally are not acidic in nature (pH<7) to interfere with the association of the feldspar with the natural material.

[0069] The addition of additives or partial replacement of nepheline syenite with bentonite (pH = 7-10) has also been found to be advantageous in improving both the oxygen and water vapor barrier properties of composites. Bentonite nanoclay is commonly used as an additive in plastics to improve barrier properties, and coatings made with mixtures of bentonite, starch, and plasticizers have been found to increase the water barrier properties of treated substrates (e.g., Applied Clay Science 2019, 183, 105272).

[0070] Zeolites can be thought of as liquid or gas absorbents that can be added to plastics to absorb unwanted odors, reduce VOC emissions, act as free radical scavengers, and act as hygroscopic desiccants (e.g., Journal of Cleaner Production 2021, 295, 126379). Addition of additives or partial replacement of nepheline syenite with zeolites having a pH > 7 is also possible.

[0071] Reinforcing agents and inert fillers include the husks (skins) or bast stems of jute, flax, hemp, isora, mesta, kenaf, ramie, toina, totora, urena, banana, roselle, rattan, and nettle; sisal, henequin, manila, curaua, pineapple, palm (areca), yucca, piassava, ca The fibers may include leaves, including cabuja, opuntia, agaves, and abaca; seeds, including cotton, calotropis, poplar, and kapok; fruits, including coconut, loofah, coir, and cocoa; grasses / reeds, including bamboo, bagasse, wheat, oats, rapeseed, rye, rice, esparto, barley, and corn; straw, reeds, and grasses; and natural cellulosic / lignocellulosic plant fibers from wood, including hardwood and softwood. Other natural fibers include silk, wool, and hair.

[0072] biodegradable Biodegradability of a polymer or composition can be defined as the physical and / or chemical breakdown of a substance at the molecular level due to the action of environmental factors, particularly enzymes derived from microbial metabolic processes. By "biodegradable," it is meant that the biocomposite resin product preferably meets, for example, the European Union Harmonized Standard EN 13432 or the American Society for Testing and Materials (ASTM) D6400. These standards define the biodegradability, disintegrability, and ecotoxicity criteria for plastics known as compostable. Biocomposite resins preferably comply with at least one of these standards. Biodegradability is typically determined by measuring the amount of CO2 produced by the biodegradable material over a period of time. The EN 13432 standard requires 90% biodegradation within 180 days, while the ASTM standard requires 60% biodegradation.

[0073] Processability The polymer composites described above can be made by the so-called "hot compounding" technique, in which components are combined under heat and shear to produce a molten plastic state (flux) that can be formed into the desired product, cooled, and develop its final strength and integrity properties. Hot compounding techniques include calendering, extrusion, injection, and compression molding to form the polymer composite into the desired shape. In other words, the method includes combining finely divided feldspar with starch and / or protein-containing materials to form a second mixture, pelletizing or grinding the second mixture, combining the second mixture with a biodegradable polymer to form a third mixture, and then melting the third mixture to form a molten mixture.

[0074] In one embodiment, the above process is carried out at temperatures, pressures and processing conditions specific to the polymer selected, for example temperatures in the range of 130-215°C, preferably 165-180°C, which may be well suited to PLA.

[0075] Polymer composites can also be made by a multi-step process, for example, by first compounding starch and / or protein-containing materials with micronized feldspar, pelletizing, and then combining the pellets or ground pellets with a polymer. In other words, the method can further include combining micronized feldspar with starch and / or protein-containing materials to form a second mixture, pelletizing or grinding the second mixture, and combining the second mixture with a biodegradable polymer to form a third mixture, followed by melting the third mixture to form a molten mixture. Additional components may be added at any step of the multi-step process. Thus, the present invention also provides pellets or ground pellets of starch and / or protein-containing materials compounded with micronized feldspar and, if present, other components, and pelletized as an intermediate product for combining with a polymer to produce a polymer composite. The intermediate product can be, for example, the second mixture described above.

[0076] The result of this method may be in the form of a solid article (or layer or portion thereof) and may include, for example, a compounded pellet, an extrudate, an injection molded article, a blow molded article, a film or rotor molded plastic article, a two-component liquid molded article, a laminate, a 3D printer filament, a felt, a woven fabric, a knitted fabric, an embroidered fabric, a nonwoven fabric, a geotextile, a fiber, or a solid sheet.

[0077] The solid article may be in the form of a coffee pod, cutlery, food tray, or single-serving package.

[0078] The invention is illustrated by the following examples.

[0079] Example 1 Three kilograms of starch flour was mixed with three kilograms of nepheline syenite powder in a planetary mixer to produce a homogeneous powder weighing approximately 6 kg. This mixture was then compounded with Ingeo 3251D PLA in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder at a starch / syenite:PLA ratio of 30:70. The screw profile used, along with the injection points for each of the component materials, is shown in Table 1. Temperature settings along the barrel were 170, 190, 170, 170, 170, 170, 170, 170°C. The compounded filaments were cooled in a water bath, dried under an air knife, and pelletized using an SG-E 60 pelletizer manufactured by Intelligent Pelletizing Solutions GmbH & Co. KG. The pellets were dried overnight at 60°C in a Dryplus 25 pelletizer manufactured by Vismec srl.

[0080] [Table 1]

[0081] Example 2 3 kg of starch flour was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a homogenous powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using Ingeo 3251D PLA in a flour / syenite:PLA ratio of 40:60. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0082] Example 3 3 kg of wheat flour was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a uniform powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using Ingeo 3251D PLA in a flour / syenite:PLA ratio of 30:70. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0083] Example 4 3 kg of wheat flour was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a uniform powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using Ingeo 3251D PLA in a flour / syenite:PLA ratio of 40:60. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0084] Example 5 3 kg of pea flour (made from blue snow peas milled in an AMA Sp. Magico EMC70 electric mill fitted with a 1 mm sieve) was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a homogenous powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder fitted with a ZS-B 25 twin-screw side feeder using Ingeo 3251D PLA in a flour / syenite:PLA ratio of 30:70. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0085] Example 6 3 kg of pea flour (made from winter beans milled in an AMA Sp. Magico EMC70 electric mill fitted with a 1 mm sieve) was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a homogenous powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder fitted with a ZS-B 25 twin-screw side feeder using Ingeo 3251D PLA in a flour / syenite:PLA ratio of 30:70. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0086] Example 7 3 kg of evening primrose meal powder (ground in an AMA Sp. Magico EMC70 electric mill fitted with a 1 mm sieve) was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a homogeneous powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder fitted with a ZS-B 25 twin-screw side feeder with Ingeo 3251D PLA (incorporating 2% w / w maleic anhydride-grafted PLA) in a ratio of 30:70 meal / syenite:PLA. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0087] Example 8 3 kg of rosehip meal powder (ground in an AMA Sp. Magico EMC70 electric mill fitted with a 1 mm sieve) was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a homogeneous powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder fitted with a ZS-B 25 twin-screw side feeder with Ingeo 3251D PLA (incorporating 2% w / w maleic anhydride-grafted PLA) in a ratio of 30:70 meal / syenite:PLA. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0088] Example 9 3 kg of coffee grounds were mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a uniform powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using Ingeo 3251D PLA in a ratio of 30:70 grounds / syenite:PLA. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0089] Example 10 3 kg of triticale flour was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a uniform powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using Ingeo 2003D PLA in a flour / syenite:PLA ratio of 30:70. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0090] Example 11 3 kg of coffee grounds were mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a uniform powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using Ingeo 2003D PLA in a ratio of 30:70 grounds / syenite:PLA. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0091] Example 12 3 kg of starch flour was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a homogenous powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using BioPBS FZ71PM in a ratio of 30:70 starch / syenite:PLA. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1, except that all barrel temperatures were set 10°C higher.

[0092] Example 13 3 kg of starch flour was mixed with 3 kg of nepheline syenite powder in a planetary mixer to produce a uniform powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using a DAN-02925 PHA in a ratio of 30:70 starch / syenite:PLA. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0093] Examples 14 to 26 The compounded pellets from Examples 1 and 13 were separately fed into the hopper of a Krauss Maffei 120-250 PX injection molding machine equipped with a 40 mm diameter screw operating at temperatures ranging from 175 to 200° C. Each melt-plasticized mixture was injection molded into plaques (three-stage plaques) with dimensions of 81 × 27 × 0.8 / 1.0 / 1.5 mm in a single-cavity cold sprue and runner edge-gate tool operating at 20° C.

[0094] Examples 27-28 The compounded pellets from Examples 1 and 3 were separately fed into the hopper of a Krauss Maffei 120-250 PX injection molding machine equipped with a 40 mm diameter screw operating at temperatures ranging from 175 to 200° C. Each molten plasticized mixture was injection molded into either a full-size cutlery fork or a full-size cutlery knife (two separate tools) in a 10-cavity hot sprue bushing sub-gate tool operating at 28° C.

[0095] Examples 29-30 The compounded pellets from Examples 2 and 4 were separately fed into the hopper of a Krauss Maffei 120-250 PX injection molding machine equipped with a 40 mm diameter screw operating at temperatures ranging from 180 to 210°C. Each melt-plasticized mixture was injection molded into capsules suitable for use in a Nespresso®-style coffee machine in an eight-cavity tool fitted with a valve-gate hot runner system operating at 28°C. Representative coffee capsules from both materials were then filled to the brim with ground coffee grains and sealed with a self-sealing aluminum coffee capsule lid. The filled capsules were tested in a standard Nespresso coffee machine to produce a consistent amount of filtered coffee. All capsules produced approximately the same amount of coffee dispensed from a commercially available Nespresso capsule.

[0096] Example 31 Representative samples of the knives and forks prepared in Examples 27 and 28 were used to ingest a meal consisting of two fried eggs, two cooked sausages, two rashers of bacon, and cooked baked beans. All of the cutlery tested was strong enough to pierce and / or cut each food item into edible pieces without deforming or breaking.

[0097] Example 32 The compounded pellets from Examples 10 and 11 were separately fed into the hopper of a Baopin Precision Instruments 25 mm single screw sheet extruder operating at 170-180°C producing 200 mm wide extruded sheets of both materials.

[0098] Example 33 The 27 x 27 x 0.8 mm plaques from Example 16 were subjected to a disintegration experiment conducted using procedures from ISO 20200 Plastics—Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test. Three sealed plastic tubs of reactors, each containing 0.5–2 wt. % plaques with holes drilled in the side for pressure equalization, were placed in a Binder KB240 incubator set at 58°C. At the completion of 90 days, the average disintegration (D) was 66%, the average reduction in volatile solids content (R) was 41%, and the variability of the results was 10%. Therefore, the test was considered valid.

[0099] Comparative Example 1 3 kg of starch flour was mixed with 3 kg of calcium carbonate (CaCO) powder in a planetary mixer to produce a uniform powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using Ingeo 3251D PLA in a ratio of 30:70 starch / CaCO:PLA. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0100] The compounded pellets were fed into the hopper of a Krauss Maffei 120-250 PX injection molding machine equipped with a 40 mm diameter screw operating at temperatures ranging from 175 to 200 °C. The molten plasticized mixture was injection molded into plaques with dimensions of 81 × 27 × 0.8 / 1.0 / 1.5 mm (three-stage plaques) in a single-cavity cold sprue and runner edge-gate tool operating at 20 °C.

[0101] The compounded pellets were fed into the hopper of a Krauss Maffei 120-250 PX injection molding machine equipped with a 40 mm diameter screw operating at temperatures ranging from 175 to 200 °C. The molten plasticized mixture was injection molded into either a full-size cutlery fork or a full-size cutlery knife (two separate tools) in a 10-cavity hot sprue bushing sub-gate tool operating at 28 °C.

[0102] Comparative Example 2 3 kg of wheat flour was mixed with 3 kg of CaCO powder in a planetary mixer to produce a uniform powder weighing approximately 6 kg. This mixture was then compounded in a Werner and Pfleiderer ZSK 25 twin-screw compounder equipped with a ZS-B 25 twin-screw side feeder using Ingeo 3251D PLA in a flour / CaCO:PLA ratio of 30:70. The screw profile used is shown in Table 1, and the injection points for each of the component materials were as in Example 1. All other details were as in Example 1.

[0103] The compounded pellets were fed into the hopper of a Krauss Maffei 120-250 PX injection molding machine equipped with a 40 mm diameter screw operating at temperatures ranging from 175 to 200 °C. The molten plasticized mixture was injection molded into plaques with dimensions of 81 × 27 × 0.8 / 1.0 / 1.5 mm (three-stage plaques) in a single-cavity cold sprue and runner edge-gate tool operating at 20 °C.

[0104] The compounded pellets were fed into the hopper of a Krauss Maffei 120-250 PX injection molding machine equipped with a 40 mm diameter screw operating at temperatures ranging from 175 to 200 °C. The molten plasticized mixture was injection molded into either a full-size cutlery fork or a full-size cutlery knife (two separate tools) in a 10-cavity hot sprue bushing sub-gate tool operating at 28 °C.

[0105] Comparative Example 3 Representative samples of knives and forks made in Comparative Examples 1 and 2 were used to consume a meal consisting of two fried eggs, two cooked sausages, two rashers of bacon, and cooked baked beans. The cutlery made with calcium carbonate was significantly more brittle than that made with nepheline syenite, with some of the tested cutlery breaking both by stabbing and / or cutting the sausages. This difference in strength was also evident in the plaques, where there was a significant difference in the degree to which the plaques made from calcium carbonate were more brittle than the plaques containing nepheline syenite. This difference was not solely due to differences in hardness between the two, as comparative plaques made from materials containing only PLA and each mineral (mixed at an equivalent percentage of 17.65% w / w) did not exhibit such a difference in brittleness.

[0106] Comparative Example 4 Representative plaques (27 x 27 x 1.5 mm) from Example 14 and Comparative Example 1 were tested for gross migration in accordance with Commission Regulation (EU) No. 10 / 2011 on plastic materials and articles intended to come into contact with food. For each simulant, four plaques were held vertically in a custom-made holder and immersed in 100 mL of simulant in a sealed, lidded glass jar. Experiments were performed in triplicate plus two blanks (i.e., no plaques). Both sets of plaques were tested in simulant A 10% v / v ethanol and simulant B 3% v / v acetic acid at 70°C for 2 hours (OM3). The results obtained for the plaques from Example 14 were comparable to the results for the 0.77 g / dm3 simulant from simulant A. 3 and 0.39 g / dm from simulant B. 3 whereas for the plaque from Comparative Example 1, the results were 7.97 g / dm from Simulant A. 3 and 39.87 g / dm from Simulant B. 3 The overall migration results for Simulant B on plaques made from calcium carbonate (Comparative Example 1) were 10 g / dm 3 as set by Commission Regulation (EU) No 10 / 2011. 3 It's beyond the limit.

[0107] The present invention can be summarized by the following clauses. 1.a. a biodegradable polymer in an amount of 1 to 98% by weight of the total weight; b. finely divided feldspar in an amount of at least 1% by weight of the total weight; c. a starch- and / or protein-containing material in an amount of at least 1% by weight of the total weight; d. optional additives; A polymer composite material comprising:

[0108] 2. The polymer composite material according to item 1, wherein a plasticizer for the starch and / or protein-containing material is not present.

[0109] 3. The polymer composite material according to item 1, further comprising a plasticizer for the starch and / or protein-containing material, the plasticizer being up to 40% by weight of the starch and / or protein-containing material.

[0110] 4. The polymer composite material according to any one of items 1 to 3, wherein component a. comprises PLA, PBS, PBAT, PHA, or a derivative or polymer blend thereof.

[0111] 5. The polymer composite material according to item 4, wherein component a. is present in an amount of 30 to 70% by weight of the total weight, preferably 50 to 70% by weight of the total weight.

[0112] 6. The polymer composite material according to any one of paragraphs 1 to 5, wherein component b. comprises micronized nepheline syenite.

[0113] 7. The polymer composite material according to any one of paragraphs 1 to 6, wherein component c. comprises flour derived from seeds, tubers, roots, grains or grass; ground expeller / meal / cake, ground pomace, ground distillers' grains, ground brewer's grains (or brewer's grains / pressure), ground biscuit meal (or biscuit cereal meal), coffee grounds, cocoa shells, or a combination thereof.

[0114] 8. The polymer composite material according to any one of items 1 to 7, wherein component d) comprises a plasticizer for component a), a compatibilizer, an antioxidant, a lubricant, a dye, a pigment, a fragrance, an odorant, a liquid or gas absorber, a small molecule absorber, a flame retardant, an oxygen and / or water vapor barrier additive, an ultraviolet absorber or stabilizer, a heat stabilizer, an infrared absorber or screener, a melt flow promoter, an impact modifier, a nucleating agent, a surfactant, a chelating agent, a coupling agent, an adhesive, a primer, a reinforcing agent, an inert filler, a fungicide, a herbicide, a fertilizer and an opacifier, a compound having a rodent repellent effect, and a wax, or a mixture thereof.

[0115] 9. A method for preparing a polymer composite material, the method comprising the steps of combining a biodegradable polymer, a micronized feldspar, and a starch and / or protein-containing material, forming a mixture, melting the mixture to form a molten mixture, forming the molten mixture into a desired product, and cooling the desired product.

[0116] 10. The method of claim 9, wherein the polymer composite is formed into the desired shape by calendering, extrusion, injection or compression molding.

[0117] 11. The method according to item 9 or 10, wherein the step of melting the mixture is carried out at a temperature in the range of 130 to 215°C.

[0118] 12. The method of any one of paragraphs 9 to 11, which is carried out in two steps, the first step being to first form an intermediate, and the second step being to combine the intermediate with the remaining components.

[0119] 13. The method of any one of paragraphs 9 to 11, further comprising, after combining the micronized feldspar with a starch and / or protein-containing material to form a second mixture, pelletizing or grinding the second mixture, and combining the second mixture with a biodegradable polymer to form a third mixture, melting the third mixture to form a molten mixture.

[0120] 14. A solid article comprising the polymer composite material according to any one of items 1 to 8.

[0121] 15. A solid article according to paragraph 14 in the form of a compounded pellet, an extrudate, an injection-molded article, a blow-molded article, a rotor-molded plastic article, a two-component liquid-molded article, a laminate, a 3D printer filament, a felt, a woven fabric, a knitted fabric, an embroidered fabric, a nonwoven fabric, a geotextile, a fiber or a solid sheet.

[0122] 16. A solid article according to paragraph 14 or 15 in the form of a coffee capsule, cutlery, straw, drink stirrer, food tray, or single-portion package, such as a cup, cap, container and / or lid, or any other single-use item.

[0123] 17. An intermediate prepared by the method according to item 12 for use in preparing the polymer composite material according to any one of items 1 to 8.

[0124] 18. The intermediate of paragraph 17, which is a mixture formed by combining micronized feldspar with a starch and / or protein-containing material.

Claims

1. a. a biodegradable polymer in an amount of 1-98% by total weight; b. Finely divided feldspar in an amount of at least 1% by weight of the total weight; c. a starch and / or protein-containing material in an amount of at least 1% by weight of the total weight; d. optional additives; e. an optional plasticizer for the starch and / or protein containing material in an amount of less than 5% by weight of the starch and / or protein containing material; A polymer composite material comprising:

2. 10. The polymer composite material of claim 1, which is free of polyol plasticizers for the starch and / or protein-containing material.

3. 2. The polymer composite material according to claim 1, wherein component e. is present in an amount of up to 4% by weight, preferably up to 3% by weight of the starch and / or protein-containing material.

4. 4. The polymer composite material according to any one of claims 1 to 3, wherein component a. comprises PLA, PBS, PBAT, PHA, or derivatives or polymer blends thereof.

5. 5. The polymer composite material according to claim 4, wherein component a. is present in an amount of 30 to 70% by weight of the total weight, preferably in an amount of 50 to 70% by weight of the total weight.

6. 6. The polymer composite material of any one of claims 1 to 5, wherein component b. comprises micronized nepheline syenite.

7. 7. The polymer composite material of any one of claims 1 to 6, wherein component c. comprises flour derived from seeds, tubers, roots, grains or grasses; ground expeller / meal / cake, ground pomace, ground distillers' grains, ground brewer's grains (or brewer's grains / pressure), ground biscuit meal (or biscuit cereal meal), coffee grounds, cocoa shells, or a combination thereof.

8. 8. The polymer composite of claim 1, wherein component d) comprises a plasticizer, compatibilizer, antioxidant, lubricant, dye, pigment, fragrance, odorant, liquid or gas absorber, small molecule absorber, flame retardant, oxygen and / or water vapor barrier additive, ultraviolet absorber or stabilizer, heat stabilizer, infrared absorber or screener, melt flow promoter, impact modifier, nucleating agent, surfactant, chelating agent, coupling agent, adhesive, primer, reinforcing agent, inert filler, fungicide, herbicide, fertilizer and opacifier, compound having rodent repellent effect, and wax, or a mixture thereof for component a).

9. 9. A method for preparing the polymer composite material of any one of claims 1 to 8, comprising the steps of combining a biodegradable polymer, micronized feldspar, and a starch and / or protein-containing material, forming a mixture, melting the mixture to form a molten mixture, forming the molten mixture into a desired product, and cooling the desired product.

10. 10. The method of claim 9, wherein the polymer composite is formed into a desired shape by calendaring, extrusion, injection or compression molding.

11. 11. The method of claim 9 or 10, wherein the step of melting the mixture is carried out at a temperature in the range of 130 to 215°C.

12. 12. The method of any one of claims 9 to 11, which is carried out in two steps, the first step first forming an intermediate, and the second step combining said intermediate with the remaining components.

13. 12. The method of any one of claims 9 to 11, further comprising, after combining the micronized feldspar with the starch and / or protein-containing material to form a second mixture, pelletizing or grinding the second mixture, and combining the second mixture with a biodegradable polymer to form a third mixture, melting the third mixture to form a molten mixture.

14. A solid article comprising the polymer composite material of any one of claims 1 to 8.

15. 15. The solid article of claim 14 in the form of a compounded pellet, an extrudate, an injection molded article, a blow molded article, a rotor molded plastic article, a two-component liquid molded article, a laminate, a 3D printer filament, a felt, a woven fabric, a knitted fabric, an embroidered fabric, a nonwoven fabric, a geotextile, a fiber, or a solid sheet.

16. 16. A solid article according to claim 14 or 15 in the form of a coffee capsule, cutlery, a straw, a drink stirrer, a food tray, or a single-portion package such as a cup, cap, container and / or lid, or any other single-use item.

17. An intermediate prepared by the method of claim 12 for use in preparing a polymer composite material according to any one of claims 1 to 8.

18. 18. The intermediate of claim 17, which is a mixture formed by combining the micronized feldspar with the starch and / or protein-containing material.

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