Functionalized olefin-maleic anhydride copolymer based additive and composite containing the additive, inorganic powder and polyolefin

Abstract

The invention relates to a functionalized olefin-maleic anhydride copolymer based additive for composites comprising inorganic powder and plastic. More specifically, the additive comprises, in addition to olefin monomers having 8-26 carbon atoms, maleic anhydride type monomers selected from the following: a) maleic anhydride (MA) monomer, b) ester type MA derivative monomer, c) N-containing MA derivative monomer, d) S-containing MA derivative monomer, wherein the ratio of the average of total number of the above maleic anhydride and / or functionalized maleic anhydride monomers to the average number of olefin monomers CR (Coupling Ratio) is 0.85-1; and wherein component a) is a mandatory component, and at least one of components b), c) and d) is a constituent of the additive. The invention also relates to a method for producing the above additive, as well as composites containing the additive.

Description

[0001] FUNCTIONALIZED OLEFIN-MALEIC ANHYDRIDE COPOLYMER BASED ADDITIVE AND COMPOSITE CONTAINING THE ADDITIVE, INORGANIC POWDER AND POLYOLEFIN

[0002] The present invention relates to functionalized olefin-maleic anhydride copolymer based additive for composites based on inorganic powder and plastic, and production and use of the composites based on inorganic powder and plastic containing additive, wherein the powder and / or the plastic is preferably waste material.

[0003] BACKGROUND ART

[0004] Nowadays waste recycling is getting more and more attention both in scientific and in industrial fields with necessity of circular economical mind-sets for resource consumption. Besides the enormous waste plastic generated yearly attention also has to be paid for the inorganic, chemically inhomogeneous industrial waste powder either being both hazardous to human health and difficult to handle because of the huge amount and small particle sizes [https: / / doi.org / 10.3390 / polyml4051050, https: / / doi.org / 10.1016 / i.matpr.2022.01.278. https: / / doi.org / 10.7763 / ITESD.201Q.Vl.25].

[0005] That waste powder has the composition of mainly one or more carbonate and / or silicate compound such as marble powder, granite powder, ceramic powder, limestone powder, dolomite powder, volcanic rock powder, brick powder, clay powder. Application of the waste powder has not been solved yet because of its small particle size. Until these days reuse both in agriculture and in cement mortar has been failed [Data from the Hungarian Asphalt Pavement Association (HAP A) for 2021; Hungarian name: Magyar Aszfaltipari Egyesiiles (HAP A)].

[0006] Literature survey revealed experiments mainly on industrial inorganic waste powders such as marble powder (CN115304295A, CN114454506A) and granite powder (CN107840640A, CN204194415U, CN107216064A, CN110743685A, CN113716939A) generated during destructive processes e.g. grinding, polishing and cutting [see also: https: / / doi.org / 10.1016 / i.asei.2018.08.005. https: / / doi.org / 10.1016 / i.compositesb.2019.106948. https: / / doi.org / 10.1016 / i.asei.2020.02.001. https: / / doi.org / 10.1016 / i.conbuildmat.2019.116766, https: / / doi.org / 10.1007 / sl0973-019-09030-w. https: / / doi.org / 10.5281 / zenodo.1333083. https: / / doi.org / 10.1016 / i.mfglet.2020.01.004]. Powders from grinding have almost the same composition making reuse considerably easier. If the waste powder has reached to a given particle size, the powder has been reused in cement or in Portland cement [https: / / doi.Org / 10.1016 / i.matpr.2022.01.278. CN101817667A, CN112174582A,

[0007] CN109650822A, CN115724638A, CN106542844A, CN112479649A, CN108892462A, CN107814519A] or in other cases road construction industry applied powder mixed into bitumen [https: / / doi.Org / 10.1016 / i.conbuildmat.2005.12.001. RU2572129C1, RU2613068C1, RU2625353C1, LT2015069A, EP4183759A1],

[0008] Waste powders have been mostly reused in thermoplastics among the solutions for plastics [https: / / doi.org / 10.1016 / i.compositesb.2019.106948. https: / / doi.org / 10.1016 / i.asei.2020.02.001, _ https: / / doi.org / 10.1016 / i.asei.2018.08.005. https: / / doi.org / 10.1016 / i.conbuildmat.2019.116766. _ https: / / doi.org / 10.1007 / sl0973-019-

[0009] 09030-w. _ https: / / doi.org / 10.5281 / zenodo.1333083, https: / / doi.org / 10.1016 / i.mfglet.2020.01.004], in other cases thermosets e.g. isopthalic acid based polyester resin, bisphenol-A diglycidyl ether based epoxy resin, etc. have been used [https: / / doi.org / 10.1177 / 0967391120926066. https: / / doi.Org / 10.1016 / i.imrt.2018.08.0121. The most widespread matrices are polyethylene (PE), polypropylene (PP), poly(etyhelene- terephthalate) (PET) and acryl-nitrile-butadiene-styrene (ABS) into which waste marble and granite powders derived from cutting, polishing, grinding are mixed [https: / / doi.org / 10.1016 / i.asei.2018.08.005. https: / / doi.org / 10.1016 / i.compositesb.2019.106948. https: / / doi.org / 10.1016 / i.asei.2020.02.001. https: / / doi.org / 10.1016 / i.conbuildmat.2019.116766. _ https: / / doi.org / 10.1007 / sl0973-019-

[0010] 09030-w. _ https: / / doi.org / 10.5281 / zenodo.1333083, https: / / doi.org / 10.1016 / i.mfglet.2020.01.004].

[0011] Blending ceramic powder (10 — 30 parts by weight) and polyolefin (30 — 60 parts by weight) with 5 — 15 parts by weight of compatibilizer in the presence of 10 — 30 parts by weight of tannic acid as flame retardant and 0.1 — 5 parts by weight of antioxidant results in increase of density and strength of the composite. Tannic acid improves adhesion between the filler material and the polymer via hydrogen bonds.

[0012] Patent document no. CN112300480A claimed for flame retarded polyolefin composites wherein 10 — 20 parts by weight of flame retardant and other additives (toughening agents, lubricants, antioxidants) have been applied besides the 30 - 50 parts by weight of polyolefin, 20 — 30 parts by weight of inorganic filler and 20 — 40 parts by weight of ceramic powder. The composite had the specific combinations of excellent mechanical properties, easy processing and in case of heavy fire the ceramic powder establishes perfect tough shell resistant to soaking and agitation.

[0013] In other cases e.g. wollastonite, which is not a waste-derived powder, was mixed into waste plastic [https: / / doi.org / 10.1016 / i.matpr.2019.05.029]. Composite from HDPE (High Density Polyethylene) waste with wollastonite disperse phase can be used as revetments (e.g. tiles) in the building industry [https: / / doi.org / 10.1016 / i.matpr.2019.05.029]. Effects of 5 — 15 %(w / w) wollastonite were investigated but no information was available about the particle morphology, pretreatment conditions (e.g. drying) or even about the properties of the waste plastic. Composites were concluded to satisfy the requirements against ceramic tiles, and thanks to the chemical resistance application possibilities in harsh chemical environments (e.g. off-shore oil rigs) were also admitted.

[0014] Compatibility of polyethylene and wollastonite could be enhanced via chemical bonds formed between the hydroxyl group of an alcohol and hydroxyl groups on the surface of wollastonite (CN107216530A) promoting better dispersion of the powder in the matrix. Antioxidants (0.1 — 0.5 part) and slipping agents (0.1 — 0.3 part) were applied among the general additives. The aforementioned alcoholic hydroxyl group was formed during the washing with alcohol (in ethanol, n-butanol or ethylene-glycol) used in the process. According to patent document no. CN103497392A, the wollastonite / HDPE composite might also have antibacterial attributes without changing the mechanical properties, HDT (Heat Deflection Temperature) and electrical conductivity. HDPE in 160 — 165 parts and wollastonite in 10 - 15 parts are required for achieving the aforementioned properties besides the 10 - 15 parts of formaldehyde, 10 parts of maleic anhydride grafted PP (polypropylene) and further introduction of zirconium-oxide, epoxidized soybean oil, phenyl-salicylate, magnesium salts and chitosan grafted methylmethacrylate components is necessary. The common solution such as maleic anhydride grafted polymer type additive at least in 5 %(w / w) was applied in order to achieve the proper concentration of reactive functional groups for advanced compatibility, according to the above patent document. In contrast, typically less than 3 %(w / w) of the additive according to the present invention was found to be sufficient.

[0015] Enhancing compatibility of the polyolefin and the wollastonite can be achieved via not only by the aforementioned proper compatibilizing additives but also surface modification or coating of wollastonite could be suitable (CN109181105A). Application of ethylene-vinyl-acetate emulsion resulted in wollastonite particles coating that helped their dispersion homogeneously in polyethylene, therefore properties of the composites improved. Coating of wollastonite with nano SiOz and graphene could be advantageous either (CN109666185A, KR100806002B1). Sharp angles of the filler are thereby passivated; smooth surfaces become rough hindering formation of local stress nucleation points and mechanical properties of the composites are also upgraded owing to increasing interfacial interactions between the filler and the matrix in the presence of the coating. Regarding to improvement of the characteristics of PP, especially its flexural properties, stearic acid and silane coupling agents are also able to modify wollastonite surface in an advantageous way.

[0016] Excellent mechanical properties and scratch resistance can be achieved in polypropylene with wollastonite (CN112210166A). Glass beads (3-20 %(w / w)) filled PP mixed with 6- 12 %(w / w) wollastonite results in ultra low density product (US11161968B2). Extrusion moulding is feasible to produce a composite with 10-20 %(w / w) filler content with applying the common additives such as antioxidants, light stabilizers and nucleating agents either. In the presence of wollastonite properties of wood flour filled PP composites can also be improved (CN103756126A). Based on the above referenced document it can be achieved with 20 - 30 parts by weight of wollastonite fibres besides the 70-80 parts by weight of wood flour related to 100 parts by weight of PP in the presence of 10-12 parts by weight of maleic anhydride grafted polyolefin type compatibilizer. In order to have the adequate ratio of reactive anhydride functional groups on the one hand a high concentration of compatibilizer, at least 5 % (w / w), is needed, on the other hand that additive, that is, the maleic anhydride grafted polyethylene behaves as a new, polymer type component in the composite system. In contrast to that, the additive according to the present invention is typically sufficient in lower than 3% (w / w) as mentioned above.

[0017] As an antioxidant combination of two types of compounds has been applied, one has been the dilauryl-dithiopropionate. Besides the compatibilizer metal carbonates and stearates and also coupling agents have been applied. That composition has been demonstrated to have 38-40 MPa tensile strength, 8-10 % elongation at break, 38-50 MPa flexure strength and 12-15 kj / m impact strength at room temperature. Eluge drawback of that solution is the requirement not only for the compatibilizing additive but also for the surface modification of the filler by further additives and coupling agents since maleic anhydride grafted polymer type additives cannot fulfil that function in such a complex composite. According to patent document no. CN111944200A, mechanical properties of the wollastonite fibres with tightened geometry can be improved by multistep grinding combined with application of stearic acid and silane coupling agents, furthermore, surface activation contributes to property enhancement of PP.

[0018] Automotive parts with more advantageous properties that even do not suffer from deformation at elevated temperatures can be produced from 20-40 parts of PP and 5-15 parts of flame-retarded PP with introducing 20-50 part of polybutylene-succinate, 15-20 parts of PA, 5-15 parts of short asbestos fibres, 5-15 parts of sisal fibres, 3-5 parts of wollastonite and 5-10 parts of polyimide, according to the Chinese patent document no. CN109705541A. Eligher elasticity was achieved by applying further elastic components such as EPDM (terpolymer of ethylene, propylene and diene) and plasticizer.

[0019] According to the patent document no. CN104592632A, PP composite with high toughness and modulus has been produced with a simple method from cheap raw materials of which production costs proved to be competitive with traditional high-toughness PP, meanwhile the new product also offers excellent performance in toughness, strength and modulus. It is composed of 50-62.5 parts of PP, 10-12 parts of HDPE, 12-15 parts of polyolefin elastomer, 6-9 parts of modified wollastonite, 0.5 — 2 parts of nano-modified particles, 1-2 parts of boron-nitride. Maleic anhydride grafted polypropylene in 5-6 parts as a compatibilizer, 1-1.5 parts of antioxidant and 2-2.5 parts of slipping agent have been applied as additives. Since the plastic matrix was a multi-component polyolefin and the compatibilizer serves as the homogenizer for those components either, therefore, the selected maleic anhydride grafted polypropylene type additive made wollastonite filler blending possible only below 10% besides the typical at least 5 % additive concentration. In contrast, according to the present invention, application of the additive in a concentration lower than 3% (w / w) results in composites with inorganic powder content above 50 %(w / w). The nano-modified filler mentioned in the referenced patent document was nano titanium-dioxide surface-treated with silane coupling agent.

[0020] The Chinese patent document no. CN102875899A advised wollastonite as a suitable candidate to make PP stronger and tougher with the recipe of 0-20 parts of toughening agent (POE, EPDM, SBS, EVA, PUR), 1-20 parts of wollastonite, 0-20 parts of stiffness improver (talc, CaCOs, wollastonite, clay, mica), 0.01-0.6 parts of stabilizer and 0.01-0.4 parts of pigment besides the 1-60 parts of PP and 0-30 parts of PE. An internal mixer, then a twin-screw extruder was used for composite production. Among the advantages of the composite the favourable mechanical properties and high flow ability were listed. Bumpers, dashboards, air conditioner parts, middle consoles and similars have been mentioned as application areas emphasizing the considerably low costs.

[0021] According to the Chinese patent document no. CN107474579A, waste plastic was used for a special automotive material production. That material contained slipping agent, antioxidant, sodium phosphate, zinc borate, plant-based ash, wollastonite fibres and tripropylene-glycol-butyl- ether besides the waste plastic. Good thermal resistance at low temperatures, appropriate elastic restitution, high impact resistance, excellent extrusion stability and long lifetime were assigned as benefits of the product.

[0022] According to the Chinese patent document no. CN116462903A, a polyolefin revetment material with high flame-retardancy and low heat emission was produced with a twin-screw extrusion technology from the mixture of ethylene-vinyl-acetate, metallocene catalyzed linear low density polyethylene, compatibilizing additive, silicone masterbatch, carbon black masterbatch, aluminium hydroxide, magnesium hydroxide, antioxidant, coupling agent and charring additive. The latter additive could be a lamellar montmorillonite, meanwhile the mica, wollastonite and carbon black could be ceramic formation aids. The proper flame retardants lead to charring, shell formation of the extruded products thereby can hinder the oozing because of overheating.

[0023] Although the widespread patent background on wollastonite powder application in plastics is available, however, the solutions are not based on waste-derived powders. Up-to-date results on waste marble powder were well summarized by Awad and Abdellatif [https: / / doi.org / 10.1016 / i.compositesb.2019.106948]. Marble powder with average particle size of 16 pm was introduced into original LDPE (Low Density Polyethylene) after drying at 100 °C. Homogeneous dispersion of particles was resoluble up to 50 %(w / w) marble powder. Increasing powder concentration resulted in better mechanical strength and thermal stability, both of which are significant aspects for application. Authors mention work of inar and Kar [https: / / doi.org / 10.1016 / i.conbuildmat.2017.12.155] being the first ones who combined waste marble powder into thermoplastic matrix.

[0024] Applicability of waste powder formed during cutting of marble building blocks was also investigated in PP besides the LDPE and HOPE [https: / / doi.org / 10.1016 / i.conbuildmat.2019.116766]. Particle fractions were separated by set of sieves of 1350 pm, 475 pm, 387 pm and 37 pm. A fixed (40 %(w / w)) powder concentration was set in order to investigate the influence of different size fractions on thermal and mechanical properties, while in order to study effects of increasing powder concentration the fraction of 387 pm was used first at 10 %(w / w), then up to 70 %(w / w) in 10 %(w / w) steps. Thermal and mechanical properties were getting the same as in LDPE and HDPE matrices [https: / / doi.org / 10.1016 / i.asei.2018.08.005. https: / / doi.org / 10.1016 / i.compositesb.2019.106948. https: / / doi.org / 10.1016 / i.asei.2020.02.001], but deterioration of mechanical properties in PP was realized at lower concentrations, below 40 %(w / w). The phenomenon of decreasing mechanical properties was attributed to agglomeration tendency of particles because increasing powder concentration lead to increasing inhomogeneity and decreasing dispersion of particles.

[0025] The Chinese patent document no. CN114957832A disclosed that polyethylene glycol terephthalate) and maleic anhydride grafted polyethylene as compatibilizers were revealed to increase strength in marble waste polyethylene composites. Thereby dust pollution during transport can be reduced and the solution is suitable for beneficial marble waste powder recycling either. For enhancing strength of the composites a combination of two distinct polymer type of compatibilizers were required that could grant the reactive functional groups capable of reacting with the marble surface at the proper concentration and the various types of functional groups enabled more surficial reaction types.

[0026] Incorporation of waste powder formed during cutting of granite and marble building blocks into HDPE was investigated by Awad et al. [https: / / doi.org / 10.1016 / i.asei.2018.08.005. https: / / doi.org / 10.1016 / i.asei.2020.02.001]. Fractions of 75 pm, 440 pm, 701 pm es 2300 pm particle sizes were retrieved [https: / / doi.org / 10.1016 / i.asei.2020.02.001], while in another experiment 37 pm, 387 pm, 475 pm and 1350 pm particle size fractions were sieved. Effects of the various particle sizes were studied at fixed, 50 %(w / w) concentration. In the study on effect of the concentration of waste powder, the concentration was increased by 10 %(w / w) steps from 10 %(w / w) to 70 %(w / w) and the particles with 387 pm and 701 pm were incorporated. It has been observed that the tendency of particle agglomeration significantly increased over 50 %(w / w) of powder content, and specific surface area of the particles decreased that resulted in deteriorating mechanical properties (e.g. flexure strength)

[0027] [https: / / doi.org / 10.1016 / i.compositesb.2019.106948].

[0028] It has been shown that similar mechanical and other physical properties can be achieved in PP within the 10 %(w / w) - 60 %(w / w) powder concentration ranges by dispersing marble and granite powders with a narrow particle size range of 300 nm - 400 nm [https: / / doi.org / 10.1007 / sl0973-019-09030-w]. It was found that testing the given particle size ranges is of great importance for health issues since those particles belong to flue-dust category (PM10, PM15).

[0029] According to Chinese patent document no. CN104744816A, polypropylene reinforced with mineral filler has high tensile strength, flexure strength and modulus and it also has significantly better properties than general PP products, therefore application areas of PP products are widening. LDPE, additives, stabilizers and plasticizers were applied besides the PP. In the reference patent document limestone fibers, muscovite fibers, ceramic fibers, nano calcium carbonate were identified as additives, and dioctyl-phthalate as plasticizer, while cresol and diphosphite derivatives as stabilizers were recommended.

[0030] According to Chinese patent document no. CN116333413A, a blend with improved weather resistance can be produced from a mixture of PP / PE (polyethylene) wastes with known ratio, which is mixed but of known, hygienic and medical, origin, with colorants and slipping agents. Apart from the additives required for improving polyolefin processability and for enhancing life-time no other additives were specified as filler. Emphasizing as a partial summary the compatibilizers for enhancing compatibility of the disperse phase (inorganic powder) and the polymer matrix were incorporated in well-known ways, but additive types were limitedly fitted to the chemical structure of the components, so only the widespread additives types were used. These are the maleic anhydride grafted PP, and PE type additives (CN114524987A, CN112300480A, CN103497392A, CN103756126A, CN104592632A, CN114957832A) or the silane type coupling agents. Common feature of the grafted polymer type additives is the potential of chemical bonds via ring-opening of the anhydride rings; the molecular weight of the additive is quite high related to the polymer matrix molecular weight, however, high concentration, typically 3 %, more likely over 5% or even in 10% or over is required in order to achieve improving the given properties or at least maintain them, but processability can be modified in lots of cases by significantly influencing the rheological behaviour.

[0031] Styrene grafted PP type compatibilizer was used in extrusion moulding of recycled polyolefin for upcycling according to the European patent document no. EP 4013820B1. Based on the experiments the polyolefin waste was derived from selective collection and / or industrial wastes having the MFI (Melt Flow Index) between 4-20 g / 10 min (230 °C, load: 2.16 kg), the most preferably 4.5-6 g / 10 min. The waste polyolefin comprised 0.5-5.0 % polystyrene, 0-4% PA6, 0-3% talc, 0-3 % calcium carbonate, 0-1 % paper, 0-1 wood, 0-0.5 % metal and 0-3% stabilizer. PP was basically isotactic type, its ratio was 30-70 %, and the ethylene content was 20- 50% (from polyethylene and ethylene containing copolymers), moreover max. 100 ppm of limonene and max. 200 ppm of fatty acid were also found. Limonene coming from the cosmetic and similar packaging materials was considered as a component of the raw material since it appears in the recycled polyolefins either. Fatty acid as a component was not detailed.

[0032] In the abovementioned patent document a styrene grafted PP type compatibilizer was applied because polystyrene contaminants in 0.5- 5% were also considered despite of the selective plastic collection. The compatibilization reaction was in situ Friedel-Crafts alkylation during reactive extrusion. Concentration of the compatibilizing additive changed between 0.3 — 4 %, and as further stabilizing additives antioxidants, acid scavengers, UV-stabilizers, nucleating agents, antistatics were applied. In that accomplishment an antioxidant (B225 FF) being a mixture of phosphorous and hindered phenol type compounds was applied in every case besides the styrene grafted PP compatibilizer, but as antioxidant hindered phenol, phosphorous, sulfur and nitrogen containing compounds or their mixture was also mentioned.

[0033] Cross-contaminant content, such as PET (polyethylene terephthalate), PA (polyamide) and PS (polystyrene) as organic, wood and paper as organic based, and glass and aluminium as inorganic types, of the commercially available recyclates of selective collected plastics generally cause difficulties in known solutions to such an extent that drastically hinders possible end-uses of the recycled product and finally in many cases no economic application remains [EP 4013820B1],

[0034] Properties of recycled iPP remain advantageous in the presence of max. 5% PE [https: / / doi.org / 10.1016 / i.wasman.2018.09.052]. PET contaminant also influence mechanical properties of PP in a negative way, therefore generally it is separated with melt filter during PP reprocessing. Fragments of inorganic materials also cause deterioration of mechanical properties over a given concentration [https: / / doi.org / 10.1016 / iwasman.2018.09.Q52].

[0035] Properties of HDPE can be deteriorated by the PP itself (e.g. due to its molecular weight) not only by its contaminants or fillers.

[0036] Since many antioxidants have high migration rates owing to the low molecular weights they disappear from the polymer surface via leaching or evaporation. High molecular weight antioxidants (1 000 g / mol or higher) are required for satisfying REACH regulations, thereby decreasing environmental and toxicological threats.

[0037] In order to exploit synergetic antioxidant effects development of stabilizers having both the primary and the secondary antioxidant functions within the same molecule would be beneficial such as a sterically hindered phenol and an aliphatic sulphide. There is a homosynergetic bifunctional antioxidant e.g. 2,2’-thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl commercially available. This compound is on the one hand volatile because of its low molecular weight, and on the other hand concentration of the sulphide functional groups responsible for secondary antioxidant function is low compared to the phenol groups, therefore it is not suitable for enduing the polymer with good thermal stability on a long-term.

[0038] Lots of thiol-containing antioxidants have been grafted onto unsaturated rubbers or rubber modified thermoplastics, in less cases onto saturated hydrocarbons (e.g. NBR, SBR, NR, EPDM, ABS), wherein role of the antioxidant are provided by various compounds such hydroxy- benzophenon, aromatic amine and hindered phenol

[0039] [https: / / doi.org / 10.1016 / i.polymdegradstab.2013.05.019, https: / / doi.org / 10.1080 / 15685551.2016.1187442, _ https: / / doi.org / 10.1016 / Q141-

[0040] 3910(80)90024-5, https: / / doi.org / 10.1002 / app.35324. https: / / doi.org / 10.1016 / SQ141-

[0041] 3910(02)00047-2. _ https: / / doi.org / 10.1007 / sl3233-014-2133-7, https: / / doi.org / 10.1016 / i.porgcoat.2021.106556].

[0042] Reactive processing is suitable for synthesizing grafted polymers applicable as conventional antioxidants later in the same or in another polymer during melt processing. This can be managed successfully if grafting of thiol-containing antioxidant onto the unsaturated polymer reach as high conversion as possible. Conversion is determined by several parameters connecting to each other: the polymer type and its melt viscosity at the reaction temperature, processing temperature, oxygen concentration, antioxidant concentration, competitive side reactions involving the antioxidants either. Other reactive components than thiols can be also applied e.g. methacryloyl, that can be grafted onto saturated polymers, such as PP, in the presence of antioxidant (hydroxy- benzophenon) but with very moderate (<20%) conversion (grafting yield). With that method thiol-containing antioxidant can also be grafted onto PP but with much lower yield than onto unsaturated rubbers indicating limitations of the approach in case of saturated polymers.

[0043] Fischer et al. [https: / / doi.Org / 10.1016 / j.polymdegradstab.2020.109099] produced high molecular weight antioxidant containing both primary and secondary functional groups in the same molecule but ratio of the sulphide groups were higher than the phenols. The bifunctional antioxidant was synthesized by thiol-ene click reaction in the access of mercapto -ethanol, then transesterification was accomplished with methyl-ester containing sterically hindered phenol. The methyl-ester is a common intermedier of various phenolic antioxidants. The thiol-ene reaction is very effective in connecting unsaturated molecules with thiols.

[0044] A two-component additive is detailed in the Hungarian patent document no. HU 227443. During further development of the component “A” in the additive package, the additives according to the present invention have been surprisingly able to provide the required complex effects in the inorganic powder / polyolefin composite in absence of the “B” component of the previous solution, moreover, functional groups formulated with the thiol compound in the additive according to the present invention also contributed to the enhanced properties. Additionally, the composites prepared with the additive according to the present invention do not require glass or carbon fibre reinforcement.

[0045] The Hungarian patent document no. HU 230449 also describes compatibilizing additives, but that additive contains significant amount of unreacted maleic anhydride groups, which is not advantageous because they tend to hydrolyse in the presence of water preferring degradation processes via formation of free carboxylic groups. That additive also does not contain any functional groups formulated with thiol compounds, moreover, it serves for production of carbon nanotube containing composites. It is also noticed that no dicarboxylic acid diester, dicarboxylic acid half-amide (dicarboxylic acid monoamide), dicarboxylic acid diamide type derivatives of MSA monomers are mentioned in that patent document, additionally, sulphur- containing derivatives according to the present invention are also not mentioned, because originally thiol reagent was not even applied. Summarizing the above detailed solutions, if any of the olefin-maleic anhydride copolymer based additive is applied, its chemical composition differs from the additive composition of the present invention, typically because either originally the maleic anhydride monomer is not functionalized or if it is, the functional groups are different.

[0046] THE TECHNICAL PROBLEM TO BE SOLVED BY THE PRESENT INVENTION

[0047] The basic technical problem to be solved by the invention is the reprocessing of inorganic waste powder and waste polyolefins both generated in huge amounts and their conversion into valuable products. This purpose has been achieved by application of the additive as the main objective of the invention, which is a multiple functionalized (multifunctionalized or multifunctional) olefin-maleic anhydride based copolymer that is able to establish properly strong bond between the inorganic powder to be processed as a disperse phase and the polyolefin to be processed as a polymer matrix.

[0048] THE RECOGNITION ON WHICH THE INVENTION IS BASED

[0049] During the systematic experimental work carried out in order to achieve the technical goal, we have surprisingly found the following.

[0050] We have found that when such an additive is used to improve the compatibility of inorganic powder and polymer matrix which comprises such an olefin-maleic anhydride copolymer (olefin-MSA copolymer) in which the maleic anhydride monomer units are partially converted into monomer units selected from the following: dicarboxylic acid ester amide, dicarboxylic acid thioester amide, dicarboxylic acid half-ester (dicarboxylic acid monoester), dicarboxylic acid diester, dicarboxylic acid thio half-ester (dicarboxylic acid monothioester), dicarboxylic acid dithioester, dicarboxylic acid half-amide (dicarboxylic acid monoamide), dicarboxylic acid diamide, dicarboxylic acid ester thioester and dicarboxylic acid imide, then the ratio of the inorganic powder component can be increased in the composite without deteriorating of the properties of the composite compared to composites comprising no additive or other type of additive. Thereby production of such a composite is possible wherein ratio of the inorganic powder component exceeds 50 % (w / w), preferably even 70 % (w / w). It should be noted that, according to prior art solutions, the mechanical properties of the composites deteriorate significantly at such a high inorganic powder content, while physical properties of the composites made with the additive according to the invention satisfy the requirements.

[0051] It also should be noted that monomer units in the copolymer (term of “monomer unit” refers to the residue of the starting monomers in the copolymer) are briefly designated as monomers in the followings for easier phrasing during discussion of copolymer composition, since it does not cause confusion in understanding, therefore it is used as common simplification in the area of expertise.

[0052] Lower concentration of the additive according to our invention was also recognized to be sufficient for production of inorganic powder-polyolefm composites compared to the prior art additives. Typically, less than 3 %(w / w) of the additive according to our invention is sufficient, while typically more than this amount is required for the prior art additives.

[0053] Further unexpected effect of our invention is that inorganic powder-polyolefm composites can be produced with the additive according to our invention, wherein particle size of the inorganic powder component does not exceed the 100 pm (as determined by a sieve having the appropriate mesh size). It also should be emphasized that application of inorganic powders with such a low particle size, preferably waste powders has not been worked out yet. In our opinion, excellent properties observed are owing to the multifunctional character of the additive according to our invention that is capable of establishing proper connections between the components even in the case of different starting materials (see details below).

[0054] Another essential aspect of our invention is that the additive according to the invention makes production of such inorganic powder-polyolefm composites possible, wherein, besides the typically waste resourced inorganic powder, the polyolefin component is also derived - partially or fully - from waste. It is important to note that additives, contaminations and compounds formed during aging processes in waste polyolefins or in their mixtures generally cause problems during reprocessing, however, in our case — in our opinion due to the multifunctional character of the additive allowing several types of interactions — end-products with adequate physical properties are obtained from such a “chemically not pure” polyolefin raw material (even without application of pure polyolefin) because such interactions are established through multifunctionality that do not evolve in the presence of conventional olefin-maleic anhydride type additives.

[0055] It was also experienced that if the multifunctional additive according to our invention is used for composite production from inorganic powder and waste polyolefin, the additive according to the invention also exerts unexpected slipping effect owing to the limited solubility of the additive, whereby application of prior art slipping agents can be avoided. Further important finding is that unexpected slipping effect of the additive according to our invention is boosted in waste polyolefins containing polyethylene terephthalate) (PET) either. It should be noted here that PET content is a serious problem in known solutions, and the additive according to the invention is also capable of exerting antioxidant effects (these positive properties are discussed in more detail below) . THE ADVANTAGES OF THE INVENTION

[0056] From both environmental and economic points of view, there has been a need for the development of a solution wherein both the powder used and the polymer material system used as matrix are derived from waste resources, since only the dispersed phase or the matrix was derived from waste according to the literature and patents, however, no solutions has been published in which both the phases, namely powder as the filler and polyolefin as the matrix, were originated from wastes. This is emphasized because the additive according to our invention can be applied for non-waste raw materials either, but it is essential for practical reasons that the additive is also suitable for waste raw materials, namely the processed powder or the matrix or both of them are originated from waste resources, these are accounted as the preferred embodiments of our invention.

[0057] It should be also emphasized that neither the publications nor the patents cover study of applicability of real (derived from waste collection) polyolefin wastes containing either organic contaminations or other type of plastics, therefore, applicability of industrial waste powders, optionally fractionated, derived from grinding processes in waste polyolefins. In known solutions typically commercially available original thermoplastics have been applied as polymer matrix, and then various powders have been introduced.

[0058] Regarding to the dispersed phase, mostly, waste powders generated during grinding, polishing and cutting of marble and granite powders have been applied according to publications so far, thus not a kind of waste powder that is derived from other industrial activities where waste powders generated in huge amounts, which cannot be recycled because of its methylene blue values (e.g. waste powder generated during road construction). Such waste powders generating in enormous amounts have been landfilled so far, but composites having appropriate properties can be produced from such waste powders with the additive according to our invention.

[0059] Industrial waste powders we used advantageously differed from other previous solutions in average particle size, particle size distribution and morphology either. One of the important features is that waste powders containing no particles above 100 pm and having average particle size below 50 pm or below even 40 pm or 20 pm can be also processed. Another important feature can be that the particle size distribution has multiple maximums below 100 pm and the waste powders contain a significant number of particles with lower than 1 pm size, typically in the 0.1 — 1 pm range, but particles being under 0.1 pm can also be processed. The third important feature, which does not still hindering processability, is that the powder to be processed can be carbonate and / or silicate based powder originated from even sedimentary or volcanic resources (hereinafter referred briefly as sedimentary and / or volcanic originated powder), of which composition differs significantly, moreover, the components can also varies within the same batch in case of higher amounts, both in size and composition.

[0060] It is important to emphasize that there are references in the literature to only up to 70 % (w / w) for maximum concentration of the disperse phase because of the processing difficulties. Each of the references concluded that properties of the composites significantly deteriorate at concentrations of 50% (w / w) or above [https: / / doi.Org / 10.1016 / j.compositesb.2019.106948]. Such compatibilizer have been developed according to our invention that makes powder concentration above 70% (w / w) be achieved (e.g. 75 to 80 % (w / w)), while properties of the composites still fulfil the requirements. In other words, processing difficulties derived from high concentration of powder have been managed to eliminate.

[0061] Two different polyolefin-rich fractions such as polyethylene (PE) films and polyolefin bottles are separated from the selectively collected plastics in Elungary, in contrast to the abovementioned patent no. EP 4013820B1. Besides those two fractions, the leaving plastic fraction at the end of the selection line (sorting residue) also contains high amount of polyolefins. Contaminants in the polyolefin fraction might be mainly poly(ethylene-terephthalate) (PET), while polyolefin fraction of the sorting residue might contain mainly PET, polystyrene (PS) and polyamide (PA) as impurities.

[0062] Processing of the abovementioned “mixed” polyolefin wastes with inorganic powders represents severe challenge that can be overcome by the additive according to our invention. During melt processing of polyolefin waste fractions having various contamination levels and melt flow properties with additive according to our invention, we surprisingly found that the powder concentration could be increased in the presence of the additive according to our invention, or composites with even 70 — 80 %(w / w), e.g. 75 %(w / w) powder concentration, could be produced, while quality of the composite did not deteriorate with variability of the waste powder composition, which otherwise often causes serious practical problems. As mentioned earlier, significant drop in composite properties was observed at 50 %(w / w) or higher powder concentrations according to literature data, therefore application of even 70 %(w / w) of powder concentration can be considered as outstanding result, if properties remain at appropriate levels. Composition of the waste powder was proved to be a determining factor in the presence of commercially available maleic anhydride grafted polyethylene additive, the maximum achievable powder concentration was only at most 20 %(w / w) with certain types.

[0063] Application of the multifunctional additive according to our invention in the recyclable plastic mixture containing mainly polyolefins, preferably waste polyolefins (having also significant polyethylene terephthalate) content in certain cases) was found to evolve appropriate interactions (even crosslinking in certain cases) between the polymer matrix and the powder particles, furthermore to enhance compatibility of the components, and the additive improves dispersibility of the inorganic powder in the plastic (polyolefin) matrix and exerts slipping effects because of its limited solubility. Thereby, it becomes possible to increase powder concentration via enhancing processability, and which effect surprisingly becomes more intensive in the presence of polypropylene (PP) besides the polyethylene. Thus the PP content might approximate 50 %(w / w), it can be e.g. 10-40 %(w / w). Application of the generally used commercial slipping agents therefore can be even avoided during reprocessing, because of the extra slipping function of the compatibilizing additive.

[0064] Slipping effect was not expected besides the compatibilizing and dispersive effects, because one essential criterion of efficiency of slipping agents is incompatibility with the polymer, meanwhile primary function of the compatibilizer is the enhancement of compatibility between the components that requires that the additive be able to dissolve into the polymer and possibly develop its effects on the powder / plastic interface without migrating to the surface of the endproduct. A feature of the additive types according to the aforementioned Hungarian patent no. HU 227443 is the joint appearance of compatibilizing and dispersive effect in plastic composites, but that can be achieved by the two-component additive in the solution according to the aforementioned patent no. HU 227443. During development of the additives according to our invention it was found unexpectedly that additive structures according to the invention can achieve said complex effects in inorganic powder / polyolefin composites even without the previously required “B” component, furthermore they have slipping effects either. The latter effect influences processing parameters in an advantageous way, e.g. by reducing the processing temperatures.

[0065] Antioxidant effect of the additive due to its sulphur containing functional groups incorporated into its structure, probably because of the acyl radicals cleaving from the thioester groups, especially prevailed in the presence of PP, was evaluated as an unexpected effect compared to the additive types according to patent no. HU 227443. Application of thioester- containing compatibilizing additives according to our invention results in eliminating or decreasing the use of antioxidant and / or stabilizing additives generally required in processing or recycling, which are necessary components in the recipes in several detailed patents (CN102875899A, CN104744816A, CN1030756126A, CN112210166A, CN107216530A, CN104592632A, CN107474579A).

[0066] REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) requirements initialize application of antioxidants having molecular weights above 1000 g / mol. That demand can be currently fulfilled by only a few type of commercially available phenol and thioester type antioxidants (e.g. Naugard 412S), but the use of compatibilizing additive according to our invention satisfies that criterion either. Stabilizing effect of the additive according to our invention in raw materials containing both polyethylene and polypropylene is considered to be significant because, due to the several types of functional groups (multifunctionality) in the additive, on the one hand, the additive has blocks similar to the thioester / hindered phenol type antioxidants generally applied, but as separate components in polyethylenes and, on the other hand, the additive has N-containing blocks similar to the N-containing compounds generally applied, but also separate components in polypropylenes. Additionally, additives according to our invention preferably contain cyclic carbonyl and free carboxylic groups either playing roles in compatibilization together with the previously mentioned functional groups. Suitable compatibility with the polyolefin-type plastic is ensured by apolar parts of the copolymer chain via solubility in the polymer.

[0067] In our invention the combination of these effects ensures the applicability of waste powder in high concentrations in waste polyolefins and the unexpected improvement in the mechanical properties, and maintaining the properties even at extreme high, above 60-70 %(w / w) concentrations.

[0068] It is also noticed relating to the abovementioned Hungarian Patent No. HU230449 that high ratio of unreacted MA monomers in the structure of the additive is not beneficial because of the tendency to hydrolysis in the presence of water, thereby favouring degradation reactions due to the free carboxylic groups. However, in lower amounts they contribute to the formation of the proper composite structure via the reaction of the carboxylic groups formed during the ringopening of maleic anhydride with other components, predominantly the powder components. Furthermore, other MA derivatives - not disclosed in the Hungarian Patent No HU230449 - can form diversified connections between the polyolefin to be processed and the powder, thereby making the end-product possible to contain a high percentage of powder in bound state, typically inorganic waste powder recycling of which has not been solved yet in industrial scale.

[0069] DETAILED DISCUSSION OF THE INVENTION

[0070] One of the subjects of the invention is an olefin-maleic anhydride (olefin-MA) type multifunctional (i.e. containing multiple functional groups) copolymer based additive, in which the MA type monomers are selected from the MA monomers and various functionalized MA monomers. The additive according to the invention is hereinafter referred to as “functionalized olefin-MA copolymer”. Further, the subject of the invention is an additive for inorganic powder and polyolefin based composites that is a functionalized olefm-MA copolymer comprising A) olefin monomers and / or oligo or polyolefin blocks consisting of olefin monomers (hereinafter summarily referred to as oligoolefin blocks) and B) MA type monomers and / or smaller blocks consisting of MA type monomers (hereinafter summarily referred to as oligo-MA blocks).

[0071] The additive according to the invention contains such a functionalized olefm-MA copolymer, optionally in a mixture with other common excipients, in which the MA type monomers are chosen from the following group: a) maleic anhydride (MA) monomer of formula (I) b) ester type monomer of formula (Ila) and (lib) : where in the formulae R1 is, in each occurrence independently from each other, C4-22 alkyl group or CH 22 arylalkyl or alkylarylalkyl group, preferably C4-22 alkyl group; c) N-containing monomer of formula (Illa), (Illb), (IIIc) or (Illd): where in formula (IIIc) R1 has the meaning defined in the previous point and in the formulae R2 is, in each occurrence independently from each other, C4-22 alkyl or Cij-22 arylalkyl or alkylarylalkyl group, preferably C4-22 alkyl group; d) S-containing monomer of formula (IVa), (IVb), (IVc) or (IVd): where in formulae (IVc) and (IVd) R1 and R2 have the meaning defined in the previous points and in the formulae R3 is, in each occurrence independently from each other, C4-22 alkyl group or CH arylalkyl or alkylarylalkyl group, preferably alkyl group; and wherein the ratio of the average of total number of the above maleic anhydride and / or functionalized maleic anhydride monomers to the average number of olefin monomers CR (Coupling Ratio) is 0.85 — 1.5, preferably 0.95 — 1.30.

[0072] The optionally used common excipient can be any kinds of materials applied as an excipient in similar compositions, such as stabilizers, colorants, consistency adjusting agents, flame retardants, glidants, antioxidants, nucleating agents, etc.

[0073] In this section we emphasize that in polymer chemistry it is conventional to describe the composition of the copolymer only statistically, specifying the main monomer types and their average ratios (or numbers) in the copolymer molecules. Therefore, in this field, a claim formulation where the product is defined by a preparation process (product-by-process claim) is also admissible, however, the protection is not bound to that the given product being prepared compulsorily by the specified process, which results in that a product with the composition falling within the scope of protection but produced using a different — typically subsequently developed — process also constitutes infringement.

[0074] The chain length of copolymers are “scattering” in practice, therefore, in this case too, only the average or distribution of the chain length can be discussed. Based on our measurements, the average number of the MA type monomers per copolymer chain is between 5 and 30, preferably between 6 and 15.

[0075] The number of MA type monomers per copolymer chain is given in the following. Here we also emphasize the statistical nature of the specified values, i.e. average numbers are specified in the following.

[0076] The average number of maleic anhydride (MA) monomer of formula (I) is d = 0.2-5, preferably 0.5-2, more preferably 0.7-2.

[0077] The average of total number of the ester type monomers of formula (Ila) and (lib) is e = 0-8, preferably 0-6, more preferably 0-4.5.

[0078] The average of total number of the N-containing monomers of formula (Illa), (Illb), (IIIc) and (Hid) is f = 0-9, preferably 0-5.5, more preferably 0-2.5.

[0079] The average of total number of the S-containing monomers of formula (IVa) (IVb), (IVc) and (IVd) is g = 0-8, preferably 0-4, more preferably 1.3-4.

[0080] As it is shown, the above d-g values can be either fractional or fractional lower than one. The appearance of fractional numbers is ensued from statistical characteristic of the MA type monomer distribution. Namely, in order to determine the values, it is theoretically necessary to determine the specific number of the various types of MA monomers in all copolymer chains, and then the average by number (arithmetical means) of the obtained values have to be calculated for each type. This value can be, of course, a fractional (or rather this is the most likely case). If there are such copolymer chains that do not contain e.g. maleic anhydride (MA) monomer of formula (I), but there are also such copolymer chains that have 1 maleic anhydride (MA) monomer of formula (I), the average by number will be lower than 1. Furthermore, if the value is higher than 0, then it can be declared that the copolymer has such a chain that contains the MA type monomer in question.

[0081] In context of the above formulae the C4-22 alkyl group refers to a straight or branched, saturated or unsaturated hydrocarbon group having 4-22 carbon atoms, and examples of which include ethyl group, propyl group, isopropyl group, butyl group, octyl group, decyl group, lauryl group, cetyl group and docosyl group, preferably decyl group, lauryl group, cetyl group and docosyl group. More preferably, these alkyl groups have 12 carbon atoms (lauryl group) or 16 carbon atoms (cetyl group).

[0082] The CH 22 arylalkyl or alkylarylalkyl group refers to a hydrocarbon group with 8-22 carbon atoms containing unsaturated cyclic part, examples of which include benzyl group, hexyl-benzyl group or ethyl-benzyl group, preferably benzyl group or ethyl-benzyl group.

[0083] At the chain end and between the MA and / or functionalized MA monomers in the functionalized olefin-MA copolymer according to the invention there are longer or shorter hydrocarbon parts derived from olefins. The hydrocarbon parts may consist of only one olefin monomer, but olefin monomers may also form olefin blocks by connecting to each other that can be referred to as oligoolefin blocks, or to as polyolefin blocks, if more than 8 olefins are connected. It is noted that the probability of formation of polyolefin blocks is small, based on the above CR value. In other words, typically, one olefin monomer or an olefin block formed by the connecting of 1 or only a few (e.g. 2-5) olefin monomers is located between the MA monomers and / or functionalized MA monomers. The olefin blocks can be identical or different, because of the statistical characteristics of the formation of connections.

[0084] The carbon atom number of the olefin (oligo)blocks depends on the carbon atom number of the olefin monomer and the number of the olefin monomers connecting in the blocks. The carbon atom number of the typical olefin monomers is generally 8-26 carbon atoms, preferably 10-22 carbon atoms, particularly preferably 14-20 carbon atoms. Preferred olefins are oc-olefins, e.g. oc-olefin with average carbon atom number of Cie-is used in example Al and oc-olefin with average carbon atom number of C12-14 used in example A2. The length of the hydrocarbon groups at the chain end is similar, generally they have 8-26 carbon atoms, preferably 10-22 carbon atoms, particularly preferable 14-20 carbon atoms, if 1 olefin monomer forms the hydrocarbon group at the chain end together with the terminal group located at the very end of the chain.

[0085] The hydrocarbon between the MA and / or functionalized MA monomers have generally 8- 26 carbon atoms, preferably 10-22 carbon atoms, particularly preferable 14-20 carbon atoms, since it is typical that one olefin monomer is located between the two MA type monomers.

[0086] For the appropriate initiator compounds for polymerization reaction, typically organic peroxides, preferably benzoyl peroxide or di (tert-butyl) peroxide are applied. These peroxide compounds not only promote the polymerization, but may also provide the end-group at the copolymer chain, because smaller radicals are also formed during their complex reaction that are able to perform this task. Typical examples of the end-group on the terminal hydrocarbon group, located at very end of the chain, are the following: benzoyl group (if benzoyl peroxide is used as the polymerization initiator), methyl group, tert-butyl group (if di (tert-butyl) peroxide is used as the polymerization initiator), further such groups may also be CH3-(CH2)P- or R’-CH(CH3)-CH2- group. Typical examples of the intermediate hydrocarbon monomers are the following: -CH2- CH(R”)- or -CH2-C(CH3)(R’)-, wherein p is 7-25, preferably 9-21; R’ is branched alkyl group with 5-23 carbon atoms, preferably branched alkyl group with 7-19 carbon atoms, examples of which include octyl group, decyl group, lauryl group and cetyl group; R” is linear alkyl group with 6-24 carbon atoms, preferably linear alkyl group with 8-20 carbon atoms, examples of which include octyl group, decyl group, lauryl group and cetyl group.

[0087] The ratio of the average of total number of the maleic anhydride and / or functionalized maleic anhydride monomers to the average of total number of the olefin type monomers in the functionalized olefin-maleic anhydride copolymer according to the invention is the coupling ratio (CR) that determines the ratio of the number of MA monomers related to the number of the olefin monomers. E.g. if CR is higher than 1, the copolymer contains more MA type monomers than olefin monomers.

[0088] The determination of CR is described in the Hungarian Patent no. HU 230449 as the following: 112 103- E - 98.6 where:

[0089] CR = coupling ratio, which is equal to average number of the MA monomer and / or functionalized MA monomers coupled to one olefin or oligoolefin molecule,

[0090] E = acid number, mg KOH / g product, = average by number of molecular weight of the starting oc-olefin monomer.

[0091] The above relationship is the simplified form of the following definition.

[0092] E

[0093] C _ _ 2 x MKOHx 103_

[0094] 1~ 2 x MKOHX IO3 X 98-6ole fin where “112 x 103” is twice of the molecular weight of KOH (during determination of the acid number one MA in the copolymer reacts with 2 KOH), and 98.6 is the molecular weight of the MA.

[0095] The acid number defines how many mg of KOH react per 1 g of copolymer. So the numerator of the above complex fraction gives the amount of substance of MA per 1 g of the copolymer. The denominator gives the amount of substance of olefin per 1 g of the copolymer (the weight of measured MA subtracted from 1 g of copolymer, divided by the molar weight).

[0096] The individual MA and functionalized MA monomer units in the functionalized olefm-MA copolymer according to the invention behave with the various waste plastic fractions in different ways.

[0097] MA monomers are reactive in ester formation and are able to establish covalent bonds with alcohol / thiol and basic groups without water formation, thereby, they are able to form strong chemical bonds with solid materials such as powders of silicate and carbonate minerals.

[0098] Dicarboxylic acid ester amide monomers are polar bifunctional groups that can interact with both esters and plastics containing acidic groups. Examples of such plastics include polyethylene terephthalate) (PET), polyacrylates, poly(vinyl acetate) (PVAc), polycarbonate (PC), and olefm-MA copolymers.

[0099] Dicarboxylic acid half-ester (or monoester) and dicarboxylic acid thio half-ester (or monothioester) monomers render partially apolar characteristic to the molecule, and due to the acidic carboxyl groups they can form ionic bonds with proton acceptor compounds. They are able to react with polar polymers, such as polyamide (PA), in stabilizing interactions.

[0100] Dicarboxylic acid imide monomers tend to form ionic bonds with acidic groups and H- bonds with other polar compounds. They enter into stabilizing interactions with polar plastics and fillers having polar surface such as silicates and carbonates.

[0101] The further monomer groups (dicarboxylic acid diester, dicarboxylic acid dithioester, dicarboxylic acid half-amide (or monoamide), dicarboxylic acid diamide and dicarboxylic acid thioester amide monomers) are also able to form bonds (possibly only secondary types), and to hydrolyse to more reactive derivatives that contain free carboxyl groups.

[0102] Furthermore, subject of the invention is an inorganic powder and polyolefin composite containing 5-80 %(w / w) (preferably 50-80 %(w / w) one or more carbonate and / or silicate compounds as inorganic powder, 20-95 %(w / w) (preferably 50-80 %(w / w)) waste plastics and 0.05-3.0 %(w / w) (preferably 0.1 — 1.5 %(w / w)) additive according to the invention, optionally together with further conventional excipients, such as reinforcing and / or filler materials.

[0103] Industrial inorganic powder, typically waste powder, having any chemical compositions can be applied in the powder and polyolefin composites according to the invention. Examples include sedimentary limestone powder, dolomite powder, volcanic rock powder, marble powder, granite powder, ceramic powder, brick powder, clay powder or the mixtures of those (see previously detailed).

[0104] Preferably, industrial waste powder fraction having particle size (average particle size (d4)) below 100 pm, preferably 20-50 pm, can be applied.

[0105] The amount of inorganic powder in the composites of powder and polyolefin according to the invention is generally 5-80 %(w / w), preferably, when the inorganic powder is required in higher ratio, 50-80 %(w / w) related to the total weight of the composite.

[0106] Polypropylene (PP), conventional polyethylenes such as high-density polyethylene (HOPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and medium-density polyethylene (MDPE) or any mixtures thereof in any ratio can be advantageously applied in the inorganic powder and polyolefin composites according to the invention. The polyolefin can be original, i.e. newly produced polyolefin or recycled, i.e. recyclable waste polyolefin.

[0107] The total amount of polyolefin in the inorganic powder and polyolefin composites according to the invention is generally 20-95 %(w / w).

[0108] Examples of further conventional additives optionally present in the inorganic powder and polyolefin composites according to the invention include colorants, glidants, foaming agents and antioxidants.

[0109] Examples of colorants include pigments, coloured fillers, such as titanium dioxide and carbon black.

[0110] Examples of glidants include calcium and zinc stearate, paraffin and waxes, or cyclic olefin copolymers, which are important additives during the processing, because they reduce friction, and therefore, the shear required for e.g. extrusion moulding.

[0111] The elasticity of the product can be improved by addition of ground elastomer (e.g. ground tire rubber) during the manufacturing process. Examples of antioxidants include trialkyl -phosphites, thioethers and dithiophosphates.

[0112] Examples of reinforcing materials optionally present in the inorganic powder and polyolefin composites according to the invention include glass fibres, carbon fibres, carbon nanotubes, basalt fibres and other natural fibres, and examples of fillers include carbon black, zeolites, gypsum, titanium dioxide, calcium carbonate and talc.

[0113] The amount of further reinforcing and / or filler materials in the inorganic powder and polyolefin composites according to the invention is generally 0-20 %(w / w), preferably 0- 10 %(w / w) related to the total weight of the composite product.

[0114] The amount of further additives commonly applied in the inorganic powder and polyolefin composites according to the invention is generally 0.1 - 4 %(w / w), preferably 1.0 — 2.5 %(w / w).

[0115] The method for preparing the additive according to the invention comprises the following steps: a) olefin (preferably oc-olefin) is dissolved in aprotic solvent (preferably in xylene, e.g. in mixture of xylene isomers), and then the solution is heated (preferably up to 90 °C — 120 °C, e.g. 105 °C); b) maleic anhydride is added into the obtained solution with stirring and preferably bubbling an inert gas, such as Nz, preferably in the presence of an initiator (e.g. benzoyl peroxide) (the addition is preferably carried out over a period of 2-4 hours, e.g. 3 hours, optionally in several portions (e.g. with 10 minutes break periods); c) after the reaction is complete, the volatile components are removed (preferably by boiling out), thus obtaining an olefin-maleic anhydride copolymer; d) the obtained copolymer is dissolved in an aprotic solvent (preferably in xylene, e.g. in mixture of xylene isomers or in DMSO, etc., preferably with stirring, preferably at 100 °C-140 °C, e.g. 120 °C); e) one or more of the thiol type, alcohol type or amine type reagents are added to the obtained solution in order to functionalize the maleic anhydride monomers, and then the solution is refluxed (at 150 °C — 200 °C, for 6-10 hours, e.g. 8 hours) with removing the reaction water; f) the volatile components are removed from the reaction mixture, preferably by boiling (preferably at 250 °C-350 °C, e.g. 280 °C, preferably under vacuum, with bubbling of inert gas (preferably Nz bubbling)), thereby obtaining the functionalized maleic anhydride-olefin copolymer final product.

[0116] Examples of the applicable reagents for functionalization include the following: alcohol type reagent: C4-22 alkyl alcohols or Cs-22 arylalkyl alcohols or alkylarylalkyl alcohols; amine type reagent: C4-16 alkylamines; thiol type reagent: C4-22 alkylthiols or Cx22 arylalkylthiols or alkylarylalkyl thiols.

[0117] Preferred embodiments of the above-mentioned reagents are those, wherein the alkyl and aryl moieties are the same as the corresponding preferred embodiments above detailed.

[0118] Production of the inorganic powder and polyolefin composites according to the invention is generally carried out by simply mixing the components.

[0119] Preferably, the additive according to the invention is mixed into the polymer melt first, and then the inorganic powder is mixed in a high concentration, preferably 40-80 %(w / w) related to the weight of the composite.

[0120] E.g. a twin-screw extruder equipped with a side feeder is suitable for mixing the components in a temperature range of 180 °C — 240 °C.

[0121] The composites containing inorganic powder and polyolefin according to the invention has advantageous mechanical properties, such as improved tensile and / or flexural strength.

[0122] Based on its beneficial properties, the composite obtained by combining the inorganic powder and polyolefin according to the invention can be applied e.g. in the building industry for the production of coatings exposed to higher stresses than the usual, components, insulation materials, furniture parts, decorations, garden tools, grids with high strength (e.g. gutter grid, snow-fence), lattices (e.g. protective fence, refractive lattice).

[0123] The method for preparing the multifunctional additive, the methods for preparation of the inorganic powder and polyolefin composites are described in the Al, A2, B, C, D and E examples, while plastic composites containing recycled waste polyolefin and inorganic waste powder according to the invention, and their advantages proven by measurement results are discussed and detailed in Tables 1 and 2.

[0124] Example Al: Example 1 of production of olefin-maleic anhydride copolymer based additives

[0125] In a 1 dm3volume four-necked glass stirring vessel 1 mol (237 g) of an oc-olefin with an average carbon atom number of Cu-is is dissolved in xylene isomer mixture (250 g), then the mixture is heated to 105 °C. 1.05 moles (103 g) of maleic anhydride (MA) and 10 g of benzoyl peroxide (as an initiator compound for the polymerization) are fed into the mixture in 3 hours, under stirring and bubbling N2 gas, with 10-minute break periods (reagents can be fed at once, but it is preferred to add them in 2-4 equal parts). After 60 minutes post-reaction the unreacted volatile components are boiled out from the reaction mixture at 250 °C and 12 kPa pressure under N2 gas bubbling. The acid number of the intermediate obtained is 329 mg KOH / g. The average coupling ratio (CR) of the maleic anhydride related to the a-olefin base material and calculated from the above mass balance is 0.98. In the second step of the synthesis, 150 g of the intermediate is dissolved in a 1 dm3volume glass stirring vessel in 75 g of xylene mixture at 120 °C, while stirring, and then a mixture of n-dodecanethiol (88.8 g) in 0.5 times molar ratio and n-dodecyl-amine (40.7 g) in 0.25 times molar ratio related to molar amount of carboxylic groups determined from the acid number are mixed into the solution in 30 minutes, and then the reaction mixture is heated to 170 °C and refluxed for 8 hours while continuously boiling out and separation of the reaction water. The ceasing of the formation of the reaction water indicates the end of the thioestering and amidating process. Volatile solvent and unreacted components are boiled out from the reaction mixture at 280 °C and 2 kPa pressure under Nz gas bubbling.

[0126] In the additive thus obtained the transformation of the carboxylic groups of the maleic anhydride incorporated into the intermediate product chain is detected by the shifts of the FT-IR absorption peaks of carbonyl groups at wavelengths of 1880 cm and 1775 cm4and the appearance of a new FT-IR absorption peaks at around wavelength of 1705 cm4. The numbers of MA and functionalized MA units (monomers) in the additive have been denoted by d, e, f and g and they have been calculated according to the publication https: / / doi.org / 10.1016 / i.heliyon.2024.e28948. the other functional groups have been calculated from the areas under the curve in a manner similar to the method for the ester groups.

[0127] Example A2: Example 2 of production of olefin-maleic anhydride copolymer based additives

[0128] In a 1 dm3volume four-necked glass stirring vessel 1 mol (180 g) of a commercially available a-olefin with an average carbon atom number of C12-14 (a-olefin content is 98 %) is dissolved in equal mass of xylene isomer mixture, then the mixture is heated to 105 °C. 1.35 moles (132 g) of maleic anhydride (MA) and 17 g of benzoyl peroxide (as an initiator compound for polymerization) are fed into the mixture in 3 hours, with stirring and bubbling N2 gas, with 10-minute break periods (reagents can be fed at once, but it is preferred to add them in 2-4 equal parts). After 60 minutes post-reaction the unreacted volatile components are boiled out from the reaction mixture at 250 °C and 12 kPa pressure under bubbling N2 gas. The acid number of the intermediate obtained is 512 mg KOH / g and the average coupling ratio (CR) of the maleic anhydride related to the a-olefin base material and calculated from the mass balance is 1.28.

[0129] The second step of the synthesis is similar to the Example Al with the difference that a mixture of n-dodecanol (63.6 g) in 0.25 times molar ratio, n-octanethiol (100.0 g) in 0.5 times molar ratio and n-butylamine (25.0 g) in 0.25 times molar ratio is mixed into the solution in 30 minutes, then the reaction mixture is heated to 170 °C and refluxed for 8 hours while continuously boiling out and separation the reaction water. The ceasing of the formation of the reaction water indicates the end of the reactions. Volatile solvent and unreacted components are boiled out from the reaction mixture at 280 °C and 2 kPa pressure with bubbling \ / gas.

[0130] In the additive thus obtained the transformation of the carboxylic groups of the maleic anhydride incorporated into the intermediate product chain is detected by the shifts of the FT-IR absorption peaks of carbonyl groups at wavelengths of 1880 cm and 1775 cm4and the appearance of a new FT-IR absorption peak at around 1705 cm4. The numbers of MA and functionalized MA units (monomers) in the additive have been denoted by d, e, f and g and have been calculated according to the publication https: / / doi.org / 10.1016 / j.heliyon.2024.e28948. the other functional groups have been calculated from the areas under the curve in a manner similar to the method for the ester groups.

[0131] Additives A3-A6 in Table 1 are synthesized in a similar process described above using the molar ratios given in the table.

[0132] Example B: Production of additive-containing masterbatch type I (containing only additive and polyolefin)

[0133] The masterbatch is produced from olefin-maleic anhydride copolymer based additive according to Example “Al” (0.2 - 20 g, 20 g in the specific Example P6) and polyolefin having a selected MFI (MFI: 45.0 g / 10 min, 230 °C, load: 2.16 kg) (20 - 200 g, 100 g in the specific Example P6) on a two-roll mill in the temperature range of 120 °C — 220 °C (140 °C — 200 °C in the specific Example P6) with friction ratio of 1.1 — 1.8 (1.2 -1.3 in the specific Example P6). If other excipient — such as colorant — is needed then it can be fed also in this step. The masterbatch type I obtained is used for co-extrusion moulding in a twin-screw extruder or for injection moulding coprocessing with inorganic powder and polyolefin wastes to produce the final product.

[0134] Example C: Production of additive-containing masterbatch type II (containing both polyolefin and powder)

[0135] The masterbatch is produced from olefin-maleic anhydride copolymer based additive according to Example “Al” (10 g), waste polyolefin having the MFI in the selected range (MFI: 2.2 — 6.6 g / 10 min, 230 °C, load: 2.16 kg) (40 g) and inorganic waste powder (60 g) on a two-roll mill in the temperature range of 140 °C — 220 °C with friction ratio of 1.1 — 1.8.

[0136] The masterbatch thus obtained containing additive and inorganic powder is mixed with the polyolefin in a twin-screw extruder to get a mixture with powder content of 40 — 75 %(w / w), and then the blend is extrusion moulded, compression moulded or injection moulded. Example D: Example 1 of production of polyolefin composite containing inorganic powder and additive (production of composite according to example P6)

[0137] To the polyolefin waste raw material having the MFI in the selected range (MFI: 4.2 — 8.3 g / 10 min, 230 °C, load: 2.16 kg) (900 g)

[0138] A) 1000 g of waste powder to be processed and 120 g of masterbatch type I having 16.7 %(w / w) of additive concentration are added, or

[0139] B) 520 g of masterbatch type II containing 100 g of original polyolefin, 20 g of additive and 400 g of waste powder to be processed, in which the additive concentration is 3.8 %(w / w), and further 600 g of waste powder to be processed is added.

[0140] The waste powder to be processed is dust of sedimentary or volcanic origin having a particle size below 100 pm. The powder is introduced through the hopper feeder or side feeder of the twin-screw extruder. The temperature zones of the twin-screw extruder are set between 170 °C — 240 °C, and the main screw speed is changed between 20 — 200 rpm (round per minute). A screw speed during extrusion is applied that results in an inorganic powder concentration of 50 %(w / w). The filament coming out from the extruder with max thickness of 10 mm is cooled down in a water bath and its mechanical properties are measured directly, and then the filament is cut into 5 mm pieces for further measurements and samples suitable for mechanical tests are produced with injection moulding.

[0141] Example E: Example 2 of production of polyolefin composite containing inorganic powder and additive (production of composite according to example P9)

[0142] The polyolefin raw material (375 g) having the MFI in the selected range (MFI: 0.5 — 3.0 g / 10 min, 230 °C, 2.16 kg), the additive in 0.45 %(w / w) according to Example “C” and the masterbatch type II (1634 g) containing inorganic, carbonate and / or silicate based waste powder of sedimentary or volcanic origin in 80 %(w / w) are introduced into an injection moulding machine. The temperature zones in the equipment are set between 170 °C — 250 °C, screw speed are changed between 10 — 200 rpm. A screw speed during injection moulding is applied that results in an inorganic powder concentration of 65 %(w / w). Samples / products suitable for investigation are produced in a mould with cooling and their mechanical properties are measured directly.

[0143] Another option for melt mixing is processing with a two-roll mill. The melt homogenized on a two-roll mill between 120 °C — 230 °C is cooled down in air, then it is ground and samples / products suitable for measurements are produced with injection moulding or compression moulding. STUDY OF THE PRODUCED MATERIAES

[0144] Practical advantages of the composites according to this invention described in general examples Al, A2, B-E are presented through specific examples of implementation (Table 1-2). Monomer ratios and properties of the additives have been given in Table 1. Table 2 contains composition and mechanical properties of the polyolefin composites in which the additives listed in Table 1 and inorganic waste powder having particle size below 100 pm or the masterbatch containing additive produced according to example B or the masterbatch containing inorganic waste powder having particle size below 100 pm and additive produced according to example C were used in the process according to example D or E.

[0145] Measurements performed with extruded filaments and standard-sized, injection moulded or compression moulded test specimens have confirmed that the concentration of inorganic waste powder can be increased in the waste polyolefin in the presence of the additive according to our invention compared to the additive-free composite, furthermore, the mechanical properties of the composites based on inorganic waste powder and waste polyolefin containing additive according to our invention can be improved by more than 20 % compared to the additive -free samples (Pl and P2) while maintaining elastic properties.

[0146] Application of the inorganic waste powder without additive (Pl and P2) resulted in deterioration of mechanical properties of waste polyolefin, as the inorganic powder has strong ability to agglomerate because of its extremely low particle size below 100 pm, therefore, heterogeneous distribution was observed in the plastic melt.

[0147] Both extrusion and injection moulding are suitable for inorganic powder / polyolefin composite processing, and in order to achieve homogeneous powder dispersion, additivecontaining masterbatch process is recommended (both masterbatch type I and II are applicable).

[0148] The maleic anhydride grafted polyolefin type commercially available additive is able to establish interaction with the groups on the surface of the powder via its maleic anhydride groups. But, based on thermal analysis, there is no effect indicating chemical interactions because of the low concentration of the anhydride groups, therefore, there is no outstanding improvement in characteristics. Moreover, the composition of inorganic waste powder also determines the achievable powder concentration, and changes in rheological properties narrows processability to extrusion moulding and compression moulding. The chemical composition of waste powder has been considered as an influencing factor when commercial additive was applied, the achievable concentration was 20% for sedimentary waste powder (M), while 30 % for volcanic type waste powder (V) (P3, P4).

[0149] When applying the additives according to this invention, an exothermic chemical reaction also occurs to an extent depending on the additive structure and waste polyolefin composition and not only the dispersion effect occurs in the presence of the additive. This contributes to better mechanical and processing (rheological) characteristics (P5, P6, P7, P12) and / or higher powder concentrations (P6, P7, P9, Pll) compared to composites without additive. The composition of the powders was not considered as a critical influencing factor.

[0150] According to our experiences the highest increase in thermal effect indicating chemical reaction can be achieved with additives containing ester functional groups. Improvement in mechanical properties can be achieved due to the strong chemical interaction compared to the composites without the additive, while maintaining the processing characteristics (P13). Thermal stability typically has been similar to the starting waste polyolefin. With increase in PP content of the waste polyolefin, the chemical reaction starts at lower temperatures, when the PP starts to melt, thereby making rheological properties can remain at a constant level.

[0151] Another significant advantage is that the same effect could be realized with the additive structure according to this invention (P13) as with the combination of ester type component “A” and the plant-based component “B” (Pl 5) according to the patent no. HU227443.

[0152] Beside the dispersion effect, slipping effect is also achieved with additives containing imide and partially amide groups (P12) due to the appropriate degree of chemical interactions, thereby injection moulding can also be possible at a specified powder concentration (P7).

[0153] Additives containing thio half-ester functional groups (Al, A2, A3, A4) have the highest thermal stability among all the additives according to this invention and they significantly enhance the thermal stability of composites compared to the additive-free counterparts. The chemical reaction between the functional groups on the powder surface and the functional groups of additive takes places above the melting temperature of PP; and the rheological properties can be modified with the composition. Thus, composites with higher powder concentration can be produced in the presence of the additives by using polyolefins with higher PP-content, and these material combinations are suitable not only for extrusion moulding (P5, P8, PIO) but also for injection moulding (P6, P7, P9).

[0154] The types and ratios of the functional groups in the additives according to the invention and the composition of the polyolefin raw material together with composition and morphology of the inorganic powder ensure that a reaction takes place between functional groups on the powder surface and functional groups of the additive in addition to the slipping effect and the dispersion of the powder particles in the polyolefin raw material, which allows to increase the powder concentration in the polyolefin raw material while achieving more advantageous mechanical and processing characteristics. able 1. Properties of functionalized olefin-maleic anhydride copolymer based additives Synthesized according to Example A2 of patent no. HU 230449 * https: / / doi.org / 10.1016 / j.heliyon.2024.e28948

[0155] Table 2. Composition, production and mechanical properties of the inorganic waste powder — waste polyolefin composites according to the invention and the reference compositions

[0156] main component (at least 90%) : M: limestone, D: dolomite, V: volcanic; particle size of the powder component is below 100 pm, average particle sizes between 25-50 pm; 230°C, load: 2.16 kg; (ISO 1133-1:2022) MFI: 8.0 g / 10 mm (190°C, load: 2.16 kg); (ISO 1133-1:2022) MFI: 45.0 g / 10 mm (230°C, load: 2.16 kg); (ISO 1133-1:2022) 15% poly(ethylene-terephthalate) and MFI: 10.0-45.0 g / 10 min (255°C, load:2.16 kg) (ISO 1133-1:2022, ISO 1133-2:2012); E: extrusion moulding F:njection moulding; H: two-roll-mill; P: compression moulding; PB: POLYBOND 3009 maleic anhydride grafted PE (commercial additive, SI Group, SA); the additive is understood to be in addition to the sum of the plastic (waste and original together) and powder components, i.e. sum of the plastic omponent(s) and powder components is considered as 100% and the amount of the additive is given in % related to those; NT: carbon nanotube; GF: glass fibre AD: other common additive; counterexample. ISO 527-1:2020; ISO 527-2:2012; ISO 527-3:2019; ISO 527-4:2022; ISO 527-5:2022; ISO 178:2019.

Claims

CLAIMS1. Additive for composites comprising inorganic powder and polyolefin, which additive is an olefin-maleic anhydride copolymer which, in addition to the olefin monomers, comprises maleic anhydride type monomers selected from the following: a) maleic anhydride (MA) monomer of formula (I)b) ester type monomer of formula (Ila) and (lib) :where in the formulae R1 is, in each occurrence independently from each other, C4-22 alkyl group or CH 22 arylalkyl or alkylarylalkyl group, preferably C4-22 alkyl group; c) N-containing monomer of formula (Illa), (Illb), (IIIc) or (Illd):where in the formula (IIIc) R1 has the meaning defined in the previous claim and in the formulae R2 is, in each occurrence independently from each other, C4-22 alkyl group or Cs-22 arylalkyl or alkylarylalkyl group, preferably C4-22 alkyl group; d) S-containing monomer of formula (IVa), (IVb), (IVc) or (IVd):where in the formulae (IVc) and (IVd) R1 and R2 have the meaning defined in the previous claims and in the formulae R3 is, in each occurrence independently from each other, C4-22 alkylgroup or C; 22 arylalkyl or alkylarylalkyl group, preferably C4-22 alkyl group; and wherein the ratio of the average of total number of the above maleic anhydride and / or functionalized maleic anhydride monomers to the average number of olefin monomers CR (Coupling Ratio) is 0.85-1.5, preferably 0.95-1.30; and wherein component a) is a mandatory component, and at least one of components b), c) and d) is also a constituent of the additive; and wherein the olefin monomer has 8-26 carbon atoms, preferably 10-22 carbon atoms, particularly preferably 14-20 carbon atoms.

2. The additive according to claim 1, wherein the average number of maleic anhydride type monomers per copolymer chain is as follows: a) the average number of maleic anhydride (MA) monomer of formula (I) is d = 0.2-5, preferably 0.5-2, more preferably 0.7-2; b) the average of the total number of ester type monomers of formula (Ila) and (lib) is e = 0-8, preferably 0-6, more preferably 0-4.5; c) the average of the total number of N-containing monomers of formula (Illa), (Illb), (IIIc) and (Illd) is f = 0-9, preferably 0-5.5, more preferably 0-2.5; d) the average of the total number of S-containing monomers of formula (IVa), (IVb), (IVc) and (IVd) is g =0-8, preferably 0-4, more preferably 1.3-4.

3. Method for producing an additive for composites comprising inorganic powder and polyolefin, comprising the following steps: a) an olefin is dissolved in an aprotic solvent; b) maleic anhydride is added to the obtained solution with stirring in the presence of a polymerization initiator compound; c) after the reaction is complete, volatile components are removed, thereby obtaining an olefin-maleic anhydride copolymer; d) dissolving the obtained copolymer in an aprotic solvent; e) adding one or more from the group of thiol type, alcohol type and amine type reagents to the obtained solution in order to functionalize the maleic anhydride monomers, then refluxing the solution while removing the reaction water; f) removing volatile components from the reaction mixture, thereby obtaining the functionalized maleic anhydride-olefm copolymer final product.

4. The method according to claim 3, wherein the one or more reagents used in step e) are one or more reagents selected from the following group: a) C4-22 alkyl alcohols, Cs-22 arylalkyl alcohols and alkylarylalkyl alcohols;b) C4-16 alkylamines; c) C4-22 alkylthiols,22 arylalkylthiols and alkylarylalkyl thiols.

5. Additive for composites comprising inorganic powder and polyolefin, which can be produced by the method according to claim 4.

6. Composite comprising an additive according to any one of claims 1 to 5 and inorganic powder and polyolefin, optionally together with further conventional additives, reinforcing materials and / or fillers.

7. The composite according to claim 6, wherein the inorganic powder is a sedimentary and / or volcanic inorganic waste powder, or a mixture thereof, having particle size below 100 pm.

8. The composite according to claim 6 or 7, comprising 5-80 %(w / w) of inorganic powder,20-95 %(w / w) of origin and / or waste polyolefin and 0.1 -3.0 %(w / w) of additive according to any one of claims 1 to 5.

9. The composite according to any one of claims 6 to 8, wherein the polyolefin is waste polyolefin from waste collection, which further contains polypropylene.

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