IT201900000073A1 - Polymeric compounds for the production of coated fabrics including biomass derived from Vitis as an active ingredient and filler - Google Patents

Description

"Polymeric compounds for the production of coated fabrics including biomass derived from Vitis as an active ingredient and filler"

The present invention relates to polymeric compounds for the production of coated fabrics, including biomass derived from Vitis as an active ingredient and filler.

Sector of the invention

The use of polymers finds very wide applications and the application of polymers in the production of coated fabrics and in the finishing of animal skins is of particular interest for the present invention, where by finishing we mean a series of mechanical and chemical operations that give the leather the look and characteristics you want. In other words, it is a phase of ennobling the surface of the leather, which gives space to the creativity of the leather technicians and “artisans”.

The compounding of polymeric materials consists in the preparation of formulations by dissolving and mixing polymers in the molten or dispersion state, additives and / or fillers. There are several fundamental criteria for obtaining a homogeneous mixture from the different raw materials. Dispersive and distributive mixing are important factors and occur through the use of appropriately set dispersers and homogenizers and twin-screw extruders (co- and counter-rotating).

Depending on the different applications, the additives used in polymeric compounds vary and are chosen from fillers or fillers, antioxidant additives, anti UV, chelating agents, compatibilizing or coupling agents and in the case of natural rubber latexes also deproteinizing additives. Fillers or fillers are substantially used in polymeric compounds as fillers to lower the cost or weight of the polymeric compound.

Background of the invention

The polymers most used in the production of coated fabrics are the following: Polyvinyl chloride (PVC); Polyurethane (PU); Polyamide (PA), Polylactic acid (PLA), Polycarbonate (PC), natural and synthetic latexes and bio-based polymers, derived from triglycerides.

Natural latexes differ according to their origin and those available on the market are those that derive from Hevea Brasiliensis, Guayule (Parthenium argentatum) and Taraxacum kok-saghyz.

In the present description, bio-based or bio-based polymers are understood to mean polymers deriving from renewable biological resources.

For oils we mean organic liquids consisting of glycerides, in particular for this application for oils we mean triglycerides of vegetable origin.

Bio-based (or biobased) polymers that can be used for the production of coated fabrics consist of unsaturated polyesters, unsaturated polyesters modified in oil, blown oils, vulcanized oils, acid-catalyzed polymerized oils, in particular using drying oils, i.e. oils containing 1,4-diene groups and / or diallyl groups (-CH = CHCH2CH = CH-).

To date, most of the fillers used in polymeric compounds for the production of coated fabrics are of inorganic nature. By way of example, CaCO3, Kaolin Clay (Al2O3 (SiO2) 2 (H2O) 2), Mica, Wollastonite (CaSiO3), Bentonite clays, calcium metasilicates, hydrated precipitated silicas, pyrogenic silicas, nanofillers and nanocomposites are mentioned.

Alternatively, lignin is also used as a filler in polymeric compounds, but is used only marginally as its cost is not competitive with respect to the cost of inorganic fillers.

In recent years, organic fillers derived from plants are also beginning to find use in the production of coated fabrics to increase the percentage of biobased additives in the polymeric compound. The vegetable-derived fillers that are already used are cellulose, wood flour, sawdust, rice husk and other vegetable fibers of various lengths.

As is known, the three main components of plant materials are cellulose, lignin and lemicellulose.

The main problem related to the use of materials of plant origin as fillers in polymeric compounds is linked to the low chemical compatibility that these materials have with respect to the polymer in which they are loaded: in fact, loading a polymer that finds application in the production of coated fabrics with a filler of vegetable origin, a mixture of a hydrophobic polymer and a hydrophilic vegetable filler is normally obtained. Thus the adhesion between the two components is very low, the interface between the polymer and the vegetable filler is very weak, not allowing the transfer of stress between the two phases, once the polymer has been loaded with the filler. This is reflected in the lowering of the elastic modulus of the finished product and in problems of fracturing the surface of the finished product. To solve this problem, if the fillers are of vegetable origin, it is therefore necessary to add compatibilizing additives that maximize the compatibility between the two phases: hydrophobic (polymer) and hydrophilic (vegetable filler). There is therefore a great desire in the sector to use natural materials that have a low cost and that come from renewable sources.

This desire is also met with the increasingly felt need to identify new outlets and new ways of enhancing agro-industry production waste, with particular reference to the vine and wine sector.

In the agri-food industry, marc is considered one of the wastewater with the highest polluting rate and the disposal of this waste and the related purification processes have been the subject of numerous studies, representing an important environmental problem, still not completely solved. . The pomace, however, can also be seen as a potential renewable resource to be exploited and, currently, most of the pomace produced is destined for thermal valorization for energy purposes: it is then sent to large plants that dry it and use it as a fuel. Although considerable resources have been invested by industry in recent years to make the processes more eco-sustainable, the waste-to-energy process has a heavy environmental impact as the gaseous emissions generated contain combustion degradation substances, such as dioxins (PCDD), furans (PCDF) and polychlorinated biphenyls (PCBs). In addition to air pollution, another inevitable result of combustion is the production of heavy and light slag (ashes) which have corrosive and irritating characteristics, so much so as to constitute one of the most dangerous waste in the industry, difficult to dispose of as characterized from extreme pH, a problem that today implies the need to implement particular cogeneration or gasification technologies.

The marc cannot even be used as a fertilizer, as the presence of the phenolic component and the acid pH inhibit the degradation processes and therefore the fertilization of the soil. On the contrary, the washout of the same and therefore of the phenols which are persistent compounds, can cause pollution of the aquifer. The only possible natural use is as a soil improver, after appropriate treatments.

The dried pomace is easily available on the market, it is collected in the wineries, which give it to the distillery. Once it arrives at the distillery, the marc is normally dissolved, dried and screened to separate its various components: Raspi (1), Bucce (2), Grapeseed (3).

The processes that the different components of the marc can undergo are many, but most of them, as indicated above, eventually become biomass for the production of energy through combustion.

The present invention therefore falls within the sector of polymeric compounds for the production of fabrics coated with additives of vegetable origin, with the aim of solving the drawbacks of the state of the art previously highlighted.

The aim of the present invention is therefore to produce polymeric compounds for the production of coated fabrics, with additives of vegetable origin, said fabrics being endowed with good mechanical resistance and great elasticity. A further aim of the present invention is also the identification of an alternative use of waste biomass derived from Vitis, implementing new models of circular economy and circular agriculture.

Very surprisingly, in fact, the Applicant has identified that the use of marc as a filler / additive in polymeric compounds for the production of coated fabrics confers unexpected properties on the polymeric compound itself, performing at the same time both the role of filler and the role of active ingredient. thanks to the presence of tannins and grape seed oil, which are able to replace or integrate the use of antioxidant, anti-UV, chelating, deproteinizing additives and compatibilizing or coupling agents that today in the coated fabric industry are for the most part synthetic in nature, from non-renewable sources.

Summary of the invention

The object of the present invention is therefore a polymeric compound for the production of coated fabrics comprising dried and micronized marc. A further object of the present invention is the use of dried and micronized marc as filler and active ingredient in a polymeric compound for the production of coated fabrics.

The present invention also relates to a polymeric film obtainable by spreading a polymeric compound comprising dried and micronized marc, on a fabric or non-woven fabric support.

Detailed description of the present invention

The present invention will now be described in greater detail in its various embodiments.

It concerns the use of dried marc (skins, stalks and grape seeds) as an active ingredient and filler for polymeric compounds and specifically for polymeric compounds intended for the production of coated fabrics.

The solution according to the present invention is particularly advantageous since it allows to reuse waste materials with a consequent economic and ecological advantage; further and main advantage is linked to the fact that dried and micronized marc flour has excellent and surprising properties as an active component and filler because:

- it comes from renewable sources, and is produced in huge quantities every year; - it contains a percentage of grape seed oil which allows it to hydrophobicize the lignocellulosic fraction, creating an apolar contact surface, which makes it suitable for mixing with an apolar polymer. This determines a greater affinity of the filler with the polymeric matrix which results in an increase in the modulus and technical characteristics. of the coated fabric, eliminating the need for the addition of coupling agents or compatibilizing agents;

- contains the tannins that give it antimicrobial, antioxidant, chelating and protein-fixing properties, allowing it to replace or supplement the use of antioxidant, anti-UV, chelating and deproteinizing additives;

- finally, being a low-cost raw material, its incorporation as a filler reduces the cost of the polymeric compound.

As previously indicated, the present invention relates to a polymeric compound for the production of coated fabrics, comprising dried and micronized marc (skins, stalks and grape seeds), in particular the polymers can be in granules, in dispersion, in aqueous emulsion, in aqueous solution or in solvent.

The polymers are chosen from polyvinyl chloride (PVC), polyurethane (PU), polyamide (PA), polylactic acid (PLA), polycarbonate (PC), natural and synthetic rubber latexes and bio-based polymers, derived from triglycerides, and mixtures of themselves. Preferably the polymers are polyvinyl chloride (PVC), polyurethane (PU), polyamide (PA) and natural rubber latexes, and mixtures thereof.

Preferably, in one embodiment, the polymeric compound according to the present invention is added with an amount ranging from 0.05 to 100 pph (parts per hundred polymer) of dried marc per 100 parts of polymer.

The dried and micronized marc preferably has a particle size ranging from 0.5 to 300 microns, more preferably from 0.5 to 70 microns, even more preferably equal to about 5 microns and a moisture content ranging from 0 to 7% w / w, preferably less than or equal to 5% w / w.

The object of the present invention is also the use of dried and micronized marc (skins, stalks and grape seeds), as filler and active ingredient in a polymeric compound for the production of coated fabrics and the polymeric film obtainable by spreading a polymeric compound comprising marc dried and micronized, on a fabric or non-woven fabric support.

The film thickness can vary from 0.1mm to 5mm.

In the preparation of the polymeric compound according to the present invention, comprising dried and micronized marc and polymer, it is possible to use marc deriving from any grape variety and all the polymers indicated above both in solid state, in aqueous dispersion or in solvent.

The composition by weight of the dried and micronized marc is variable, but on average it has this distribution

- Peels (1): 61% w / w

Stalks (2): 22% w / w

Grapeseed (3): 25% w / w

(1) The skins have the composition shown in the following table 1:

Table 1

The qualitative-quantitative composition of the tannins present in the skins is influenced by a certain number of variables, but it appears useful to report a characterization performed on dried films isolated from marc by HPLC-DAD-ESI-MS, in order to highlight the classes of tannins present. : Table 2

(2) The stalks have the composition shown in the following table 3:; Table 3

(3) The grape seed has the composition shown in the following table 4:

Table 4

The qualitative and quantitative composition of the tannins present in grape seeds is influenced by a certain number of variables, but it appears useful to report a characterization performed on grape seeds (from hydroalcoholic extract) by HPLC-DAD-ESI-MS, in order to highlight the classes of tannins present:

Table 5

In the tissues of the fruits coming from Vitis vinifera L. there are mainly condensed tannins; in the marc they are contained in particular in the skins and in the grape seed as well as in the stalk, with different contents and types of tannins.

The tannins identified in the skins are based on units of catechin, epicatechin and epicatechin-3-O-gallate; there is also epigallocatechin which is not present in grape seeds. The polyphenolic polymers of a tannic nature present in the skins are made up of longer chains (over 80 units) than those contained in the grape seed (the chains do not exceed 30-35 units).

Thanks to the presence of the aforementioned polyphenols, the pomace (skins, stalks and seeds), suitably dried and micronized, once incorporated into a polymeric compound, works as an active component, acting as an antioxidant, anti-radical, chetant, anti UV and deproteinizing agent.

Polyphenols, as natural antioxidants, in fact act as excellent electron donors or hydrogen donors towards the radical molecules that are formed by initiators, such as UV radiation, oxygen, metals, heat. The phenoxy radical that is formed from the reaction of phenol with the radical molecule, is stabilized through the delocalization of the unpaired electrons on the aromatic ring. The antioxidant characteristics of polyphenols are also linked to their ability to chelate metals.

The antioxidant activity of the tannins within the polymeric matrix is therefore due to the OH- groups present in the aromatic rings of the tannins, i.e. the phenoxy groups that capture the oxygen molecules, in addition to an indirect antioxidant effect due, precisely, to the capacity chelating against the metals that gallic tannins possess, that is the complexation of some metal cations that normally play the role of catalyst in oxidation reactions.

It is important to keep in mind that polyphenols act synergistically and the overall composition influences the antioxidant activity of the pomace additive. The deproteinizing activity is due to the ability of tannins to form complexes with protein molecules, complexes that subsequently precipitate. The formulations based on condensed tannins, especially from grape seeds, are the most reactive thanks to their lower degree of polymerization. The mechanisms involved in the formation of tannin-protein complexes are varied: hydrogen bonds between COOH groups and OH radicals, hydrophobic or electrostatic interactions. Furthermore, both the molecular mass of the protein and its proline content affect the final reaction: the larger these two factors, the greater the possibility of coupling with the tannic molecule and consequent formation of the tannin-protein complex. Proteins of smaller size or with a compact structure of the globular type are little involved in the formation of complexes with tannins.

The deproteinizing properties that the tannins contained in the marc (skins, seeds and stalks) have is particularly advantageous when the polymer or part of the polymer compound consists of an aqueous dispersion of "naturai rubber latex" (NRL).

The term "Naturai rubber latex" refers to a natural polymer dispersion, consisting of polyisoprene, water and other constituents such as proteins, lipids and inorganic salts, defined as a whole as "non-rubber constituent". In particular, according to the definition provided by the US FDA (Food and drug Administration), the term "naturai rubber latex" indicates a rubber that is produced from a natural rubber latex by a process that involves the use of natural rubber in a suspension. colloidal concentrate.

Naturai rubber latex has excellent technical properties and is a totally biobased and natural polymer. However, the use of this polymer in the industrial field and more precisely in the production of coated fabrics presents problems related to the high protein content of this natural polymer, proteins that can cause allergies if not removed effectively. Naturai rubber latex contains two types of proteins: large proteins bound to polyisoprene (rubber) particles and low molecular weight water soluble proteins.

The use of marc as a functional additive in polymeric compounds, surprisingly allows to reduce the extractable protein content of the polymeric compound in general and of the natural rubber latex in particular, thanks to the ability of the tannins to fix proteins, forming aggregates / complexes that remain trapped between the polymer particles in general, polyisoprene in particular, and are thus not subject to the elution process which, during the drying process of the film, would have carried them towards the outer surface of the coated fabric.

By film we mean a more or less thin film, which is applied to a fabric by spreading and which gives it the visual and tactile effect of a "skin". Coated fabric refers to the product composed of fabric and film. The film in the reference industrial sector is generally referred to as "coating", while the fabric can have a variable nature and constitutes the support on which the coating takes place, necessary for the mechanical and workability properties of the finished product.

It is particularly surprising that these properties of the tannins / polyphenols present in the marc remain unchanged even in the polymeric compound, and are able to perform their action also in the polymeric compound and in the film obtained from it.

It should be remembered that in the science of polymers the additives that are used as antioxidants, anti UV, chelators, are pure substances with standardized activity that are synthesized at low cost, from non-renewable raw materials.

The tannins extracted from the marc, already used as functional additives in the food sector, are first extracted with a hydroalcoholic extraction, concentrated and made available to the market in pure form and have a cost that is 5 to 10 times higher than the cost of the original additives. synthetic. In such applications in the food sector, the extraction and purification of tannins are necessary steps, because the tannins would be too diluted in the lignocellulosic mass in which they are dispersed and would not be usable in products that require the properties of tannins, but not the action. of filler of the lignocellulosic fraction.

On the other hand, it seems surprising that the functional activity of tannins is so high, even when they are not subjected to the preliminary extraction and purification phase: in the compounding phase, in fact, the polymer is mixed with the dried and micronized marc, i.e. with a mixture in which they are present lipid, polymeric and lignocellulosic phase. Surprisingly, compatibility is established such that the tannins do not remain confined in the lignocellulosic matrix, but on the contrary are distributed fairly evenly, unexpectedly conferring their functional properties on the finished product. Therefore, the use of dried and micronized marc allows surprisingly to obtain a low-cost polymeric compound, without or with low use of additives deriving from non-renewable sources and without the need for pre-extraction and purification phases of the tannins.

Method of preparation

The marc used as additive / filler in the polymeric compound according to the present invention is prepared starting from the biomass of Vitis as follows: the marc is subjected to a first drying phase in a drying oven at a temperature of 105 ° C for the time necessary to obtain a residual humidity ranging from 0 to 7% w / w, preferably less than or equal to 5% w / w.

The dried marc thus obtained is subjected to a very thorough micronization which allows to obtain a particle size ranging from 0.5 to 300 microns, more preferably from 0.5 to 70 microns, even more preferably equal to about 5 microns.

Preferably the polymers used for the production of coated fabrics are polymers in aqueous solution or in solvent and the incorporation of the dried and micronized marc is carried out by forming a homogeneous dispersion with mills or with stator / rotor homogenizers and with the help of additives dispersants.

Suitable dispersing additives can be chosen from cellulosic derivatives such as carboxymethylcellulose or other inorganic dispersants such as Bentonite.

Once the polymeric compound according to the present invention has been prepared as described above, it is spread to form a film having a thickness of about 0.9 mm, with a laboratory coating machine.

To evaluate the effect of fillers and active components on the mechanical properties of the film (and to prevent the fabric support from distorting the measurements), the tests were carried out by spreading the film on paper.

The film is then dried and polymerized at the temperature of the polymer used for each polymer compound and detached from the paper.

On the sample of film thus obtained, tests were carried out to characterize the mechanical properties following accelerated aging by means of thermo-oxidative and photo-oxidative stress.

Accelerated aging

The film was subjected to accelerated aging tests at a relative humidity (RH) of 0%, by thermo-oxidative stress at 90 ° C and exposed to the light of a mercury UV lamp (λ> 250 nm) up to a time of 1000 h (photooxidative stress).

Samples were collected at different exposure times and the degradations occurred in these samples were evaluated.

Trials

To test the mechanical properties, tests were carried out in parallel on films obtained starting from polymeric compounds in which dried and micronized marc according to the invention was incorporated and on films obtained from polymeric compounds in which an equal amount of lignocellulosic material was incorporated. (lignin, hemicellulose and cellulose) in order to evaluate the additive effect with pomace, having a specific composition in tannins and oil, compared to the effect of a filler with the same lignocellulosic composition. To test the anti-UV and anti-radical properties, tests were carried out in parallel on films obtained starting from polymeric compounds in which dried and micronized marc according to the invention was incorporated and on films obtained from the polymeric compound as it is.

The mechanical properties of the obtained film (Young's modulus, yield strength, elongation at break, resistance at break) have been tested according to the ASTM D 882: 2012 standard.

The ASTM 5712: 2015 method was used for the verification of extractable proteins.

Other features and advantages of the invention will be evident from the following examples given for illustrative and non-limiting purposes.

Example 1

A polymeric compound was prepared consisting of a polyurethane (PU) dispersion (total solids content 45% w / w; Viscosity (CPS): 100-250; pH: 8) in which a 70% aqueous dispersion was incorporated. % by weight of Nebbiolo marc, micronized to 5 microns and with a humidity of 5%, in the following percentages by weight with respect to the total weight of the polyurethane dispersion: 10%, 20% and 30%. Viscosity is measured according to the ISO 3219: 1993 method. The mechanical properties of a sample of PU film only, of samples of PU film with wood flour additives (with qualitative and quantitative composition in terms of cellulose / hemicellulose / lignin similar to that of marc) and of film samples were then evaluated. obtained starting from polymeric compounds with additives of dried and micronized marc. The films were prepared as indicated in the descriptive part of the present application and precisely: the polymer dispersion was inserted in a laboratory rotor / stator homogenizer, at a speed of 200 revolutions per minute (rpm) and was then added with a dispersion of water / marc / dispersant previously prepared until a homogeneous compound is obtained. The compound was then spread with a laboratory coater with manual doctor blade on backing paper at a thickness of 0.9 mm. Subsequently the film was dried, polymerized, detached from the paper and tested.

Tests for the evaluation of anti-UV and antioxidative activity were performed on representative samples, after having subjected them to accelerated aging by thermo-oxidative and photo-oxidative stress.

The previous tables show how the content of grape seed oil present in the marc acts surprisingly as a compatibilizer, allowing at the same time an improvement in the mechanical properties of the film obtained and a homogeneous distribution / action of the tannins. The above results also show how the tannin content of the marc acts as an antioxidant, anti UV, ketant additive, resulting in greater resistance of the film obtained to thermo-oxidative and photo-oxidative stress, without the need for a preventive phase of extraction and purification of the tannins.

On the contrary, an equal addition of lignocellulosic fillers determines a lowering of the mechanical properties and a reduced resistance of the film obtained to thermo-oxidative and photo-oxidative stress.

Example 2.

A polymeric compound was prepared consisting of a polyvinyl chloride (PVC) dispersion (total solids content 35% w / w; Viscosity (CPS): 80-150; pH: 7.5), in which a dispersion was incorporated 70% aqueous marc having the same characteristics indicated in Example 1 in the following percentages by weight with respect to the total weight of the polyvinyl chloride dispersion: 10%, 20% and 30%.

The mechanical properties of a sample of PVC film only, of PVC film samples with pure cellulose additives and of film samples obtained starting from polymeric compounds with marc additives were then evaluated. The films were prepared as indicated in Example 1.

Tests for the evaluation of anti-UV and antioxidative activity were performed on representative samples, after having subjected them to accelerated aging by thermo-oxidative and photo-oxidative stress.

Claims (10)

CLAIMS 1. Polymeric compound for the production of coated fabrics comprising dried and micronized marc and at least one polymer. 2. Polymeric compound according to claim 1, wherein the dried and micronized marc has a particle size ranging from 0.5 to 300 microns, more preferably from 0.5 to 70 microns, even more preferably equal to about 5 microns and a content of humidity ranging from 0 to 7% w / w, preferably less than or equal to 5% w / w. 3. Polymeric compound according to one or more of the preceding claims, comprising a polymer selected from polyvinyl chloride (PVC), polyurethane (PU), polyamide (PA), polylactic acid (PLA), polycarbonate (PC), natural and synthetic rubber latexes, and mixtures thereof, preferably the polymers are polyvinyl chloride (PVC), polyurethane (PU), polyamide (PA) and natural rubber latexes, and mixtures thereof. 4. Polymeric compound according to one or more of the preceding claims comprising a polymer of partially or completely vegetable origin, choosing between polylactic acid (PLA), polyhydroxalkanoate (PHA), polyhydroxobutyrate (PHB) and polyurethane (PU), and mixtures thereof, preferably i polymers are polyhydroxobutyrate (PHB) and polyurethane (PU), and mixtures thereof. 5. Polymeric compound according to one or more of the preceding claims, wherein the polymeric compound comprises an amount ranging from 0.05 to 100 pph (parts per hundred polymer) of dried marc per 100 parts of polymer. 6. Use of dried and micronized marc as filler and active ingredient in a polymeric compound for the production of coated fabrics. Use according to claim 6, wherein the dried and micronized marc has a particle size ranging from 0.5 to 300 microns, more preferably from 0.5 to 70 microns, even more preferably equal to about 5 microns and a moisture content ranging from 0 to 7% w / w, preferably less than or equal to 5% w / w. 8. Use according to one or more of the preceding claims 6 or 7, where the dried and micronized marc is added to a polymer selected from polyvinyl chloride (PVC), polyurethane (PU), polyamide (PA), polylactic acid (PLA), polycarbonate ( PC), natural and synthetic rubber latexes, and mixtures thereof, preferably the polymers are polyvinyl chloride (PVC), polyurethane (PU), polyamide (PA) and natural rubber latexes, and mixtures thereof. 9. Use according to one or more of the preceding claims 6 or 7, where the dried and micronized marc is added to a polymer of partially or completely vegetable origin choosing between polylactic acid (PLA), polyhydroxalkanoate (PHA), polyhydroxobutyrate (PHB) and polyurethane (PU), and mixtures thereof, preferably the polymers are polyhydroxobutyrate (PHB) and polyurethane (PU), and mixtures thereof. Use according to one or more of the preceding claims 6 to 8, wherein the polymeric compound comprises an amount ranging from 0.05 to 100 pph (parts per hundred polymer) of dried marc per 100 parts of polymer.