COMPOSITE SUBSTANCES WITH VEGETAL PRODUCTS, USES AND PRODUCTION PROCESSES OF COMPOSITE SUBSTANCES

Abstract

The present invention discloses composite substances that can be used in the production of objects and building materials by means of fusion thereof, and provide particular physical properties, including barrier to the transmission of ultraviolet radiation and to the transfer of liquids and gases, whereby said composite substances present thermoplastic matrixes that include synthetic polymers and/or bio-polymers, as well as further vegetal fibre associated with at least one sub-product from the processing of an edible vegetal substance, thereby providing a new economic utilization of such sub-products, and composite substances with a high degree of bio-degradation once of the disposal thereof.

The present invention further discloses uses of said composite substances and processes for production of said composite substances.

Claims

1. A composite substance including polymers, characterized in that said composite substance presents a thermoplastic matrix that includes natural fibres from sub-products of processing of vegetal species, and that presents a fusion point of less than 200° C.

2. The composite substance according to claim 1, characterized in that said composite substance presents a thermoplastic matrix that includes at least one of: synthetic polymers, and biopolymers, in particular polymers of vegetal origin, whereby the thermoplastic matrix is reinforced with natural fibres of sub-products of processing of vegetal species, preferentially including at least natural fibres of coffee silverscreen obtained from processing green coffee beans, in particular from roasting of green coffee beans, whereby the thermoplastic matrix preferentially presents physical characteristics, including properties of barrier to ultraviolet radiation transmission and to fluid transfer in the same order of magnitude, at most only with one order of magnitude of difference, as the corresponding values that are specific of the polymers present in the composition thereof.

3. The composite substance according to claim 1, characterized in that said composite substance presents a composition that includes natural fibres of sub-products resulting from at least one of: mechanical and thermal processing of vegetal species, preferentially aromatic vegetal species, whereby it is preferred when said composite substance includes at least one from the list of natural fibres associated with a sub-product of at least one of: processing of green coffee beans, such as fibre of coffee silverscreen; processing of cinnamon, such as fibre of cinnamon husk; processing of locust bean, such as fibre of locust bean husk; processing of rice, such as fibre of rice husk; whereby the composite substance presents values of parameters of barrier to ultraviolet radiation transmission and to fluid transfer that are preferentially in the same order of, at most only with one order of magnitude of difference, as the corresponding values that are specific of the polymers present in the composition thereof.

4. The composite substance according to claim 1, characterized in that said composite substance presents a thermoplastic matrix that includes natural fibres of vegetal sub-products, and at least one of the following synthetic polymers: a polyethylene from the list that includes high density polyethylenes and low density polyethylenes (LDPE), poly-glycolide (PGA); polycaprolactone (PCL); poly u-valerolactone (PVL); thermoplastic amide (TPS); ethylene copolymer and vinyl alcohol (EVOH); polyvinylidene chloride (PVDC), whereby it is preferred when the bio-polymeric matrix does not include poly-lactic acid (PLA).

5. The composite substance according to claim 1, characterized in that said composite substance presents a bio-polymeric matrix that includes natural fibres of vegetal sub-products, preferentially including at least fibre of coffee silverscreen, and further at least one of: BioPBS (poly-butylene succinate); poly-lactic acid (PLA); whereby it is preferred when the bio-polymeric matrix does not include poly-lactic acid (PLA) PLA.

6. The composite substance according to claim 1, characterized in that said composite substance presents a mass ratio of fibre of coffee silverscreen bigger than 10%, preferentially bigger than 20%, whereby it is preferred when, in the case of including synthetic polymers, the mass ratio of fibre of coffee silverscreen is comprised between 10% and 60%, preferentially between 10% and 40%, and in the case of including bio-polymers, the mass ratio of fibre of coffee silverscreen is comprised between 10% and 60%, preferentially between 20% and 40%.

7. The composite substance according to claim 1, characterized in that said composite substance presents a mass ratio of bio-polymers of at least 40%, preferentially of at least 60%, whereby the mass ratio of bio-polymers can be comprised between 40 and 90%, preferentially between 50 and 80%.

8. The composite substance according to claim 1, characterized in that said composite substance includes a compatibilizing agent, whereby the compatibilizing agent is preferentially a synthetic polymer, for example polyethylene, grafted with maleic anhydride (PE-co-MA), or a bio-polymer, for example BioBPS, grafted with maleic anhydride.

9. The composite substance according to claim 1, characterized in that said composite substance presents a mass ratio of compatibilizing agents of at most 30%, preferentially at most 20%, whereby the mass ratio of compatibilizing agents can be comprised between 5 and 30%, preferentially between 7 and 20%.

10. The composite substance according to claim 1, characterized in that said composite substance that includes synthetic polymer and fibre of coffee silverscreen presents a water vapour transfer rate (WVTR) of less than 20 g/m.sup.2.Math.day, preferentially less than 10 g/m.sup.2.Math.day, particularly preferentially less than 5 g/m.sup.2.Math.day, at ambient conditions of 38° C., 90% RH for film of 1 millimetre, and in that said composite substance that includes synthetic polymer and fibre of coffee silverscreen presents and oxygen transfer rate (OTR) of less than 500 cm.sup.3/m.sup.2.Math.day, preferentially less than 250 cm.sup.3/m.sup.2.Math.day, particularly preferentially less than 150 cm.sup.3/m.sup.2.Math.day, at ambient conditions of 38° C., 90% RH for film of 1 millimetre, and in that said composite substance that includes synthetic polymer and fibre of coffee silverscreen presents a light transmission of less than 20%, preferentially of less than 10%.

11. The composite substance according to claim 1, characterized in that said composite substance presents at least one of: a density of less than 1,3 kg/m.sup.3, preferentially less than 1,1 kg/m.sup.3; a fluidity index of at least 1,5 g/10 min, at 190° C., preferentially of at least 3,0 g/10 min, at 190° C., a fusion temperature of less than 200° C., preferentially less than 170° C., particularly preferentially less than 150° C.

12. A method of using a composite substance, comprising use of material sub-products from the processing of vegetal species for production of said composite substance, and the use thereof for production of building materials, such as for filling or coating, and of objects associated with the distribution and consumption of edible or pharmacological substances, such as for the collection of perishable substances, such as edible substances.

13. The method according to claim 12, further comprising use of a sub-product from the processing of coffee beans, including the utilization of coffee silverscreen resulting from drying and roasting of green coffee beans, for producing composite substances, including polymers, which comprises a thermoplastic matrix that includes natural fibres from sub-products of processing of vegetal species, and that presents a fusion point of less than 200° C.

14. The method according to claim 12, characterized in that includes the use of the composite substance for production of objects by means of mould injection, by means of tri-dimensional printing, or for coating of objects by means of material printing or deposition.

15. The method according to claim 12, further comprising use of the composite substance for production of objects or coatings of rigid, semi-rigid or flexible objects.

16. The method according claim 12, further comprising use of the composite substance for production of packages of edible substances requiring barrier at least to the transfer of fluids, including with a stable bi-dimensional structure, for example in the form of a capsule for collecting an individual portion of roasted and ground coffee beans, tea and other aromatic edible substances, or with a flexible dimensional structure, such as for example in the form of film.

17. A process for producing a composite substance according to claim 1, said process including the following steps: providing a first quantity of at least one of: synthetic polymers, and bio-polymers; providing a first quantity of natural fibres associated with a sub-product of a previous processing of a vegetal species, including at least one natural fibre from the list that includes coffee silverscreen, cinnamon husk, and other aromatic vegetal substances; providing a bio-composite mixture of said first quantities of natural fibres with remaining polymers, in particular according to a previously defined mass fraction; melting a quantity of the bio-composite mixture at a temperature lower than 200° C., preferentially lower than 150° C.; providing the fusion of bio-composite mixture to a following step of process.

18. The process according to claim 17, characterized in that the total quantity of natural fibres associated with a sub-product from the processing of a vegetal species, is of at least 10%, preferentially of at least 20% in mass fraction of the bio-composite mixture, whereby it is preferred when the remaining mass fraction of the bio-composite mixture is provided at least in its most part by bio-composites.

19. The process according to claim 17, characterized in that further includes the following steps: providing a previously configured mould of object relating to an object for collection of edible substance, such as for example a container part of a capsule for collection of edible substance or the aromatic type; injecting the fusion of bio-composite mixture in the mould of object.

Description

DESCRIPTION OF THE FIGURES

[0037] The invention shall be hereinafter explained in greater detail based upon preferred embodiments and the attached Figures.

[0038] The Figures Show:

[0039] FIG. 1: graphic of viscosity of a first embodiment of a composite substance according to the present invention;

[0040] FIG. 2: graphic of viscosity of a second embodiment of a composite substance according to the present invention;

[0041] FIG. 3: graphic of thermal behaviour of coffee silverscreen, obtained after roasting of coffee beans;

[0042] FIG. 4: graphic comparing the first and second embodiments according to the present invention;

[0043] FIG. 5: graphic of spectrometry comparing the first and second embodiments according to the present invention;

[0044] FIG. 6: SEM-captured image from a sample of first embodiment according to the present invention, in a first zooming scale;

[0045] FIG. 7: SEM-captured image from a sample of first embodiment according to the present invention, in a second zooming scale;

[0046] FIG. 8: SEM-captured image from a sample of first embodiment according to the present invention, in a third zooming scale.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0047] According to a first aspect, the present invention discloses composite substances that present in their composition natural fibres resulting from the processing of vegetal species, i.e., material sub-products form mechanical and/or thermal processing thereof.

[0048] According to another aspect, the composite substances present natural fibres of sub-products resulting from the processing of vegetal species, as well as further at least one of: synthetic polymers and bio-polymers of vegetal origin.

[0049] It is herewith provided a valorization of sub-products from agro-industrial processes, or other, as well as a reduction of the consumption of polymers of relatively higher economic and/or environmental costs.

[0050] In particular, the composite substances according to the present invention present properties appropriate for several uses including for use in the production of objects by means of injection in moulds, or by means of tri-dimensional printing.

[0051] In particular, the composite substances are adapted to provide protection relative to light, water vapour, to oxygen, to microbial contaminants, to chemical contaminants.

[0052] The composite substances disclosed by the present invention are therefore appropriate for the production of collecting objects, in particular of the type packages or parts thereof, that provide protection of perishable substances along a so-called shelve-life or commercial life period, i.e. presenting degradation of its physic-chemical properties, when exposed to ambient water vapour and oxygen.

[0053] Said perishable substances can be edible substances, in general, requiring a substantial protection of water vapour barrier, and can further be edible substances with aromatic profile, in particular furthermore requiring a protection of oxygen barrier.

[0054] Said aromatic edible substances can be precursor substances of aromatic beverages, such as for example roast and ground coffee beans, soluble coffee, tea, chocolate, lyophilized foods and other similar substances.

[0055] One example of the use of composite substances disclosed by the present invention is the case of packages of the type capsules, pods and similar, and with a semi-rigid, rigid or film-like dimensional form.

[0056] The composite substances disclosed by the present invention can be used in the mould injection of objects, in similar manner to the mould injection of composite substances including synthetic polymers and/or bio-polymers.

[0057] The present invention shall be hereinafter described based upon embodiments associated with the use of a particular sub-product resulting from the processing of green coffee beans by roasting: the coffee silverscreen.

[0058] In this sense, there are described examples of completely or substantially biodegradable composite materials, reinforced with coffee silverscreen resulting from the roasting processing of coffee beans.

[0059] In particular, two mixtures of BioPBS with coffee silverscreen have been tested.

[0060] In the case of a first embodiment of the composite substance according to the present invention, a thermoplastic matrix including bio-polymer (BioPBS) with coffee silverscreen present in a mass fraction of 10,7% has been tested.

[0061] In the case of a second embodiment of the composite substance, a thermoplastic matrix has been tested that has a mass fraction 10,7% of fibre of coffee silverscreen, but that further includes the addition of a compatibilizing polymer to increase the interfacial adhesion between the PBS and the fibres of coffee silverscreen. The selected polymer was EVA-co-MA (Fusabond C 190) because contains the required functional group (maleic anhydride) grafted in the main structure of the EVA (ethylene vinyl acetate) and because presents a fusion temperature (71° C.) that is appropriate to the process. The EVA-co-MA has been added in a mass fraction of 14,9%. Experimentally, is has been established that the BioPBS and the EVA-co-MA were indeed mixable, which reinforced the justification for using this additive. The main disadvantage of this polymer is being of non-biodegradable petrochemical origin.

[0062] The mixtures of BioPBS with coffee silverscreen have been made at a 140° C., so as to apply temperatures reasonably higher than the fusion temperature of the PBS (115° C.) and testing conditions that are closer to those used in the industry.

[0063] In both cases, the viscosity of the mixtures has kept stable for successive additions of constant fractions of coffee silverscreen, at a temperature of 140° C. the viscosity of the first embodiment (see FIG. 1) is inferior to the viscosity of the second embodiment (see FIG. 2), for the same concentration of fibres of coffee silverscreen, because the EVA-co-MA additive has a relatively low fluidity index.

[0064] The thermal behaviour of the coffee silverscreen, resulting from the roasting process of coffee beans da, is represented in FIG. 3. The coffee silverscreen in this case contains 10% in weight of water and its thermal degradation occurs at about 200-400° C. The residue at 600° C. corresponds to 30% in weight. The test has been carried out under inert atmosphere.

[0065] The results of the characterization of the thermal behaviour compare the BioPBS polymer with the first embodiment (see FIG. 4). The polymer alone, BioPBS, presents a degradation profile in a single step (340-440° C.) and the residue at 600° C. is negligible.

[0066] The first embodiment of composite including fibre of coffee silverscreen has the fusion peak at 122° C. The results also show that a fraction of about 10% in mass of ECO 10 starts degrading at temperatures superior to 200° C. (220-360° C.), whereby the remaining 90% (m/m) are degraded up to 420° C. At 600° C., the sample consists in a carboniferous residue that corresponds to about 7% (m/m) of the initial sample. The mass low of 10% corresponds to the mass content in fibres.

[0067] This embodiment of composite substance can thus present a fluidity index of at least 1,5 g/10 min at 190° C., preferentially of at least 3,0 g/10 min at 190° C.

[0068] Moreover, it has been shown as particularly advantageous the fact that these composite substances according to the present invention present a fusion temperature smaller than 200° C., preferentially smaller than 170° C., particularly preferentially smaller than 150° C.

[0069] Moreover, in particular in what refers to the use of these substances for production of confinements, or other type of objects, by means of injection in mould or coating applications of other materials, the composite substances according to the present invention can present the following intervals of characteristic operational parameters: [0070] injection pressure between 30 and 150 bar, preferentially between 50 and 100 bar, [0071] compaction pressure between 5 and 30 bar, preferentially between 10 and 20 bar.

[0072] The spectrometry by means of FTIR (“Fourier-transform Infrared spectroscopy”) of two composite material relating to the first and second embodiments is represented in FIG. 5. As can be observed, it is not possible to distinguish the contribution of the compatibilizing agent, in this case the EVA-co-MA, in the spectrum of the second embodiment (referred as “2nd Embodiment”).

[0073] The macroscopic aspect of the composite materials, at the exit of the mixer, is very homogeneous. The resistance to manual fracture, tested in empirical manner, is high for the thickness and forces applied. The compatibilizing agent should increase the adhesion between the fibres and the matrix, increasing the mechanical resistance of the composite and decreasing the permeability of the material by fluids, that is, the barrier to the fluid transmission, including to gases (oxygen, water vapour).

[0074] The microstructure of the composites associated with the first embodiment corresponds to a material whereby it is easier to observe the matrix than the fibres (see FIGS. 6 to 8). As can be observed in the images obtained by SEM (“Scanning Electron Microscopy”) the matrix has edges, and should correspond to relatively fragile polymer. The characteristic morphology of the fibre of coffee silverscreen is evidenced in some images that identify the fibres, or the impressions left when separating the fragments for observation.

[0075] The composite substance according to the present invention can include synthetic polymer and fibre of coffee silverscreen so that presents a water vapour transfer rate (WVTR) of less than 20 g/m.sup.2.Math.day, preferentially of less than 10 g/m.sup.2.Math.day, particularly preferentially of less than 5 g/m.sup.2.Math.day, at ambient conditions of 38° C., 90% RH for film of 1 millimetre.

[0076] The composite substance according to present invention can include synthetic polymer and fibre of coffee silverscreen and present an oxygen transfer rate (OTR) of less than 500 cm.sup.3/m.sup.2.Math.day, preferentially of less than 250 cm.sup.3/m.sup.2.Math.day, particularly preferentially of less than 150 cm.sup.3/m.sup.2.Math.day, at ambient conditions of 38° C., 90% RH for film of 1 millimetre, thereby providing barrier to water vapour and oxygen transfer. These properties are relevant for the production of recipients of collection of perishable substances that degrade as a result of exposure to ambient atmosphere.

[0077] The composite substance according to the present invention can include synthetic polymer and fibre of coffee silverscreen so that presents a negligible light transmission.

[0078] The thermoplastic matrix of the composite substances according to the present invention can, therefore, present physical characteristics, including properties of barrier to the transmission of ultraviolet radiation and to the transfer of fluids, in the same order of magnitude, at most with only one order of magnitude of difference, as the corresponding specific values of the polymers present in the composition thereof.

[0079] The scope of the present invention is naturally not limited by the examples above.

[0080] As shall be promptly understood by the reader, it is further possible to use fibres of other sub-products of processing of vegetal species, such as for example: locust bean husk, cinnamon husk and rice husk.

[0081] Moreover, these substances can be combined not only with polymers of vegetal origin, but also as polymers of synthetic and fossil origin.