CH715042A2 - Composite material based on natural material containing scleroproteins. - Google Patents

Abstract

The invention relates to a composite material based on particles of a natural material containing scleroproteins, in particular horn or leather. These particles are dispersed in a matrix of a thermoplastic polymer chosen from polyamide 11 and polyether-block amides. A process for preparing this composite material comprises mixing said particles and said thermoplastic polymer and forming this mixture.

Description

Description: The present invention relates to the development of renewable natural resources, in particular protein residues of animal origin.

More particularly, the present invention relates to a composite material based on particles of a natural material containing scleroproteins and a thermoplastic polymer, as well as a process for the preparation of such a composite material. The invention also relates to the use of such a composite material for the manufacture of an article of composite material, as well as such an article of composite material.

The planned depletion of fossil resources has been encouraging manufacturers for several years to develop alternative solutions using renewable resources, and this in all areas of industry. The recycling and recovery of animal or vegetable waste is of increasing interest in this respect, both from an economic and environmental point of view.

It has for example been proposed by the prior art to manufacture composite materials from animal waste and polymer. Examples of such composite materials, based on keratinous material, are described in document US 2006/0 084 728.

The mechanical properties of such composite materials are however very uneven, and their production, as well as their use for the manufacture of molded articles, often pose problems.

The present invention aims to provide a composite material based on particles of a natural material, in particular of animal origin, and of polymer, which has good mechanical properties, in particular in terms of both mechanical strength, and which can easily, and with good reliability and good reproducibility, both be prepared and be used for the manufacture of molded articles, by means of hot forming techniques commonly used in the industry.

An additional objective of the invention is that this composite material is entirely, or almost entirely, of natural origin. In particular, the invention aims for this composite material to contain an amount by weight of less than 25%, and even less, for example less than 5%, of components which are not biobased.

It has been discovered by the present inventors that such objectives are achieved by a combined choice of a particular type of natural material, natural materials containing scleroproteins, and of specific thermoplastic elastomers.

Scleroproteins, otherwise known as fibrous proteins, constitute one of the three main classes of animal proteins. These are long, filament-shaped molecules that play a structural and constitutive role in the body, and which are involved in the composition of so-called support tissues, such as bones, antlers and connective tissues, as well as integuments, such as skin, hair, horns, hooves, and nails, and in ivory. There are different types: keratins, which form protective tissues in the body, such as the epidermis, hair, nails, hooves, horns or feathers of birds; collagens, which are connective tissues, such as cartilage; conchyoline, which forms the shells of molluscs, for example oysters; and elastins, also found in connective tissues.

Many industrial wastes from livestock, such as horn, feathers, leather, or production waste, such as scrap generated during leather work or horn work, etc., are mainly consisting of scleroproteins. The use of this waste for the manufacture of articles made of composite material, intended for multiple and varied applications taking advantage of the aesthetic and mechanical properties of these natural materials, proposed by the present invention, makes it possible to make an entirely advantageous recovery, both economically and environmentally.

In the present description, the term “natural material” means a material of natural origin, as opposed to synthetic materials, such as a material of animal origin.

According to a first aspect, the present invention relates to a composite material based on particles of a natural material containing scleroproteins, these particles being dispersed in a matrix of a thermoplastic polymer. This thermoplastic polymer is chosen from polyamide 11 and polyether-block amides, or any of their mixtures.

In the present description, the term "natural material" includes both a single natural material and a mixture of several different natural materials, each of which contains scleroproteins.

Preferably, the natural material used contains more than 50% by weight of scleroproteins. This is the case for the majority of natural materials of animal origin based on scleroproteins: scleroproteins are often substantially the only type of protein present there.

Polyamide 11, commonly designated by the abbreviation PA11, is a particular thermoplastic polymer obtained by polycondensation of a C11 amino acid, 11-aminoundecanoic acid. This polymer has many advantages, in particular that of a biobased origin, the 11 -aminoundecanoic acid which can be extracted from a plant, Ricinus communus, also known by the name of castor oil.

CH 715 042 A2 Such a polymer is in particular commercially available, for example sold under the name Rislan® PA11 by the company Arkema.

The polyether-block amides, commonly designated by the abbreviation PEBA, are for their part thermoplastic block copolymers comprising one or more flexible polyether blocks, and one or more polyamide blocks, which also have the advantage of being able be obtained at least partially from renewable resources.

The polyamide blocks preferably comprise at least one polyamide block chosen from PA6, PA12 and PA11, PA11 being particularly preferred in the context of the invention.

The polyether blocks preferably comprise at least one polyether block chosen from poly (ethylene oxide), polyethylene glycols, polytetramethylene glycols and poly (tetramethylene oxide).

The polyether-block amides used in the context of the invention may contain all percentages by weight of polyamide block (s) and of polyether block (s), the copolymer being all the more flexible as its percentage by weight of polyether block (s) is high.

The polyether-block amides used according to the invention are also preferably UV stabilized.

Such polymers are in particular commercially available, for example sold under the name PEBAX® by the company Arkema.

In particular embodiments of the invention, the thermoplastic polymer is a polyether-blockamide chosen from PEBAX® of grade 35R53 or grade 25R53, these grades defining the Shore D hardness of the copolymer (equal to 35 for the grade 35R53 and 25 for grade 25R53).

The particular thermoplastic polymers chosen according to the invention to enter into the composition of the composite material have in particular the advantage of being able to be used in a wide range of processes for shaping materials, and in a wide range of temperature. They make it possible to prepare and shape composite materials in accordance with the invention in a particularly reliable, controlled and reproducible manner, including when the particles of natural material are highly hygroscopic.

It has also been discovered by the present inventors that the composite material according to the invention, incorporating such thermoplastic polymers, has particularly good mechanical resistance, its mechanical properties having good stability over time, including when 'it is exposed to a humid environment.

The composite materials in which the thermoplastic polymer is a PEBA also have good flexibility, with a degree of flexibility that can advantageously be controlled in a particularly reliable and reproducible manner by an adequate choice of the particular copolymer used, in particular of the weight ratio between its polyether blocks and its polyamide blocks, its proportion in the mixture and the particle size of the particulate natural material.

The composite material according to the invention also has a beautiful aesthetic appearance, close to that of natural material, its composition is homogeneous and it is advantageously stable, both physically and aesthetically. The feeling when touched is also advantageously close to that of natural matter.

The above properties make the composite material according to the invention entirely suitable for use in a wide range of applications.

The natural material containing scleroproteins used in the composition of the composite material according to the invention is for example of non-human animal origin.

In particular embodiments of the invention, this natural material is chosen from horn, leather, wood and ivory from non-human animals, shell shells, and any of their mixtures.

It can otherwise consist of wool, hoof, hair or feathers of non-human animals.

The scleroproteins which are contained in the natural material forming part of the composite material according to the invention are, for example essentially keratin scleroproteins.

Preferably, the composite material according to the invention contains 30 to 60%, in particular 30 to 55%, by weight of particles of said natural material, relative to the total weight of said composite material. Such a range of values advantageously ensures properties to the touch close to those of natural material, as well as an aesthetic appearance very close to that of natural material.

The composite material according to the invention may also contain one or more additives, chosen according to the final properties desired for this composite material. Nonlimiting examples of such additives are plasticizing agents, coupling agents, dyes, pigments, etc.

Preferably, these additives are present in the composite material in an amount less than 10% by weight, preferably less than 5% by weight, relative to the total weight of the composite material.

The particles of natural material present in the composite material according to the invention preferably have dimensions between 100 and 500 μm.

CH 715 042 A2 According to another aspect, the present invention relates to a process for the preparation of a composite material according to the invention, this material meeting one or more of the characteristics described above.

This preparation process comprises a step of mixing particles of the natural material containing scleroproteins and the thermoplastic polymer, chosen from PA11, PEBA and their mixtures.

This mixing is preferably carried out by compounding (also designated by the terms "intimate mixing"), that is to say by mixing at a temperature above the melting temperature of the thermoplastic polymer, and if necessary cooling. It is within the skill of a person skilled in the art to determine this melting temperature, in particular by differential enthalpy analysis (commonly designated by the abbreviation DSC, for English Differential Scanning Calorimetry). This melting temperature is also generally indicated by the suppliers of commercially available thermoplastic polymers.

The temperature applied for the mixing step is also preferably lower than the degradation temperature of the natural material. Again, it is within the competence of a person skilled in the art to determine the degradation temperature of the natural material used. To this end, a person skilled in the art may in particular carry out a thermogravimetric analysis (ATG) of a sample of the natural material, in a conventional manner in itself.

The mixing, where appropriate compounding, of the particles of the natural material containing scleroproteins and of the thermoplastic polymer, can be carried out according to any conventional method in itself for the skilled person. It can in particular be produced by extrusion, for example by means of an extruder, for example single or twin screw, or an internal mixer, according to conventional operating parameters.

In particular embodiments of the invention, the particles of natural material have dimensions of between 20 and 500 μm, preferably between 100 and 500 μm. By this is meant that all their dimensions are included in these size ranges.

Preferably, these particles have good size homogeneity, as well as preferably good shape homogeneity, which it is in particular possible to ascertain by observation with an electron microscope.

The natural material in particulate form containing scleroproteins used in the process according to the invention preferably has a humidity level of between 0 and 20%, for example around 12%.

Here we define the humidity level, conventionally in itself, as the percentage by mass of water contained in the material, relative to the total mass of material, under conditions of 60% of relative air humidity at around 20 ° C. This humidity level can in particular be determined by comparing the weight of a sample of material with the weight of this same sample after it has been subjected to a drying step at more than 100 ° C. until a weight is obtained. of the substantially constant sample.

Where appropriate, the method according to the invention may comprise, prior to the step of mixing the particles of the natural material and the thermoplastic polymer, a prior step of drying the natural material used, to obtain the desired humidity level. This drying step can be carried out in a suitable conventional device in itself, for example in a ventilated oven. It is within the skill of those skilled in the art to determine the proper temperature and drying time to achieve the desired humidity level.

The process for preparing a composite material according to the invention may also comprise initial stages of cleaning, sorting and / or degreasing of the natural material, as well as, where appropriate, that a prior stage of grinding of this natural material so as to ensure that it is in a particulate form, and if necessary at the desired particle size.

During or at the end of the step of mixing the particles of the natural material and the thermoplastic polymer, various additives, in particular one or more plasticizing agent (s), one or more agent (s) coupling, one or more dye (s), pigment (s), etc., can be incorporated into the mixture.

In particularly preferred embodiments of the invention, the process for preparing a composite material comprises a step of shaping, in a shaping device, the material obtained in the step of mixing particles of natural matter and of the thermoplastic polymer.

This shaping step can be carried out according to any conventional method in itself for the skilled person, in particular by injection, extrusion, molding, compression molding, injection blow molding, etc.

The shaping device is also conventional in itself.

The shaping is preferably carried out at a temperature above the melting temperature of the thermoplastic polymer, and preferably below the degradation temperature of the natural material used.

In particularly advantageous embodiments of the invention, the step of mixing the particles of the natural material and the thermoplastic polymer is carried out directly in the shaping device, in which therefore are carried out at the both the preparation of the composite material, and its shaping.

There is thus advantageously obtained, according to the invention, from the initial ingredients, a directly shaped composite material, in the form of an article of composite material, in particular of a molded article, of the desired shape.

CH 715 042 A2 The method according to the invention is thus advantageously simple and quick to implement.

The preparation of the composite material according to the invention can for example be carried out by injection molding, for example by means of an extruder, in particular a twin-screw extruder.

For example, a process for preparing a composite material according to the invention can be carried out by injection molding, using an extruder, with an extrusion temperature profile for example between 90 and 210 ° C. for the particular case of a mixture of particles of cow horn and PA11.

The preparation process according to the invention may otherwise comprise mixing by kneading particles of the natural material and the thermoplastic polymer, then compression molding, at a temperature between the melting temperature of the polymer and the temperature of degradation of natural matter. For example, for the aforementioned particular case of particles of cow horn and PA11, the conditions applied in the mold can be 198 ° C. under a pressure less than 10 MPa, for approximately 15 minutes.

According to another aspect, the present invention also relates to the use of a composite material according to the invention, meeting one or more of the above characteristics, for the manufacture of an article made of composite material, in particular by shaping said composite material, as described above.

The invention also relates to an article of composite material made of a composite material according to the invention, in particular a molded article.

This article can for example be an accessory or small fashion accessory, an article of leather goods, jewelry, watches, tableware and art of living, the field of packaging , decoration, etc.

Another aspect of the invention is a more general method of manufacturing an article made of composite material, comprising the preparation of a composite material in accordance with the invention and the shaping of this composite material, at the desired shape.

The composite material according to the invention can firstly be shaped into a form suitable for its storage, for example in the form of granules, then, secondly, it can be shaped to form l article according to the invention, in the final form desired for this article.

The characteristics and advantages of the invention will appear more clearly in the light of the following implementation examples, provided for illustrative purposes only and in no way limit the invention.

Materials and methods The polymers used for these examples are the following:

Rislan® PA11 T natural 2P from Arkema, melting temperature 183-188 ° C (measured according to ISO 1218)

Arkema Pebax® 35R53 SP 01, melting temperature 135 ° C (measured according to ISO 11357)

Pebax® Rnew 35R53 SP 01 from Arkema, melting temperature 136 ° C (measured according to ISO 11357) In the examples below, the extrusion operations are carried out in a Clextral EV25 twin-screw extruder with the following parameters:

screw rotation speed:

220 rpm material flow: 1.4 kg / h average extruder torque: 22 N.m average pressure in the die 11 bar of extrusion:

The injection operations are carried out in the same device, also with the above operating parameters.

For each experiment below, a temperature profile is applied in the extruder, between the feed hopper and the extrusion die, the minimum value and the maximum value of which are indicated for each experiment.

In all the examples below, granules are formed by extrusion of a mixture of polymer and natural material, then these granules are subjected to injection molding.

CH 715 042 A2

Example 1 - Bovine horn and PA11 Compounding by extrusion-granulation of the following substances is carried out, in the following weight percentages:

particles of bovine horns of Aubrac and Salers origin crushed and micronized, of gra- 42% w / w nuometry 250 μm (degradation temperature between 210 and 230 ° C)

PA11

54.5% w / w

Citrofol® AHII (bio-based plasticizer)

1.5% w / w carbon black ENSACO®250G

2% w / w by extrusion with an extrusion temperature profile between 90 and 200 ° C.

We obtain a composite material of black color, shaped in the form of granules, about 0.5 mm in diameter and 0.5 mm thick.

These granules are introduced into an injection molding unit, comprising the twin-screw extruder described above.

The temperature profile applied in the extruder is between 180 and 200 ° C. The mold temperature is maintained at 60 ° C.

We obtain a homogeneous part, of shore D hardness of about 70-80, with good dimensional stability.

Example 2 - Cattle horn and PA11 The compounding of the following substances is carried out in the following weight percentages:

particles of bovine horns of Aubrac and Salers origin crushed and micronized, of gra- 31.5% w / w nuometry 250 um (degradation temperature between 210 and 230 ° C)

PA11

65% w / w

Citrofol® AHII (bio-based plasticizer)

1.5% w / w titanium dioxide (TiO ₂ )

2% w / w The operating conditions used are as described in Example 1 above.

We obtain a homogeneous part with a blond-brown shade, dimensions 148 x 105 mm. Its properties are similar to those of the part obtained in Example 1, with good dimensional stability. The exterior rendering is mat and uniform.

Example 3 - Crust of mammoth ivory and PA11 The compounding of the following substances is carried out in the following weight percentages:

mammoth fossil ivory crust powder from Siberia, size 50% w / w

303 μm

PA11

50% w / w The operating conditions used are as described in Example 1 above, with the exception of the injection molding step, for which the injection temperature profile is between 180 and 210 ° C and the mold temperature is 130 ° C.

We obtain a piece of dimensions 60 x 60 x 4 mm, dark in color tending to brown, with a granitic effect due to the composition of mammoth ivory. This part has good dimensional stability.

Example 4 - Deer antler and PA11 The compounding of the following substances is carried out in the following weight percentages:

deer antler powder, particle size 303 μm

30, 40 or 50% w / w

CH 715 042 A2

PA11 qs 100% w / w The operating conditions used are as described in Example 1 above, with the exception of the injection molding step, for which the temperature profile of injection is between 180 and 210 ° C and the mold temperature is 130 ° C.

For each of the 3 mixtures tested, a piece of dimensions 60 x 60 x 4 mm is obtained, of smooth appearance, of beige / green color which becomes more marked the more the composite materials are more loaded with particles. deer antlers. This part has good dimensional stability.

Example 5 - Oyster shell and PA11 The compounding of the following substances is carried out in the following weight percentages:

original oyster shell powder from the Thau basin, with a particle size of 280 μm 30, 40 or 50% w / w

PA11 qs 100% w / w The operating conditions used are as described in Example 1 above, with the exception of the injection molding step, for which the temperature profile of injection is between 190 and 210 ° C and the mold temperature is 110 ° C.

For each of the 3 mixtures tested, an off-white / beige part is obtained, the darker the more the composite materials are more loaded with oyster shell particles. The rendering is not homogeneous, a seed effect is visible, due to the grain size of the filler. This part has good dimensional stability.

Example 6 - Soft Leather and PEBA The compounding of the following substances is carried out in the following weight percentages:

Dust used to disengage orange-colored sheep leathers, with a particle size of 157 μm 30, 40 or 50% w / w

Pebax® Rnew 35R53 SP 01 qs 100% w / w The operating conditions used are as described in Example 1 above, with the exception of the temperature profile in the extrusion step, which is between 150 and 190 ° C, and with the exception of the injection molding step, for which the injection temperature profile is between 170 and 190 ° C and the mold temperature is 40 ° vs.

For each of the 3 mixtures tested, a flexible piece of dark brown color is obtained, the darker the more so that the composite materials are more loaded with leather particles.

Example 7 - Soft Leather and PEBA The compounding of the following substances is carried out in the following weight percentages:

Dust used to disengage orange-tanned sheep leathers, with a particle size of 157 μm 40 or 50% w / w

Pebax® 35R53 SP 01 qs 100% w / w The operating conditions used are as described in Example 1 above, with the exception of the temperature profile in the extrusion step, which is between 150 and 190 ° C, and with the exception of the injection molding step, for which the injection temperature profile is between 135 and 190 ° C and the mold temperature is 40 ° C .

For each of the 2 mixtures tested, a flexible piece of dark brown color is obtained, the darker the more so that the composite materials are more loaded with leather particles.

Example 8 - Soft Leather and PEBA The compounding of the following substances is carried out in the following weight percentages:

blue full grain calf leather powder, grain size 500 μm 40% w / w

CH 715 042 A2

Pebax® 35R53 SP 01 60% w / w The operating conditions used are as described in Example 1 above, with the exception of the temperature profile in the extrusion step, which is between 130 and 160 ° C, and with the exception of the injection molding step, for which the injection temperature profile is between 130 and 160 ° C and the mold temperature is 40 ° C.

One obtains a part of bluish green / turquoise hue, of homogeneous appearance with stain effects, semi-rigid, of Shore D hardness of about 50.

Example 9 - Soft Leather and PEBA The compounding of the following substances is carried out in the following weight percentages:

blue full grain calf leather powder, particle size 250 μm 40% w / w

Pebax® 35R53 SP 01 60% w / w The operating conditions used are as described in Example 1 above, with the exception of the temperature profile in the extrusion step, which is between 125 and 165 ° C, and with the exception of the injection molding step, for which the injection temperature profile is between 175 and 190 ° C and the mold temperature is 50 ° C.

We obtain a part of bluish green / turquoise hue, of homogeneous appearance with stain effects. Its shore D hardness is approximately 30.

Claims (10)

claims 1. Composite material based on particles of a natural material containing scleroproteins, said particles being dispersed in a matrix of a thermoplastic polymer, characterized in that said thermoplastic polymer is chosen from polyamide 11 and polyether-block amides , or any of their mixtures. 2. Composite material according to claim 1, in which said scleroproteins are keratin proteins. 3. Composite material according to claim 1, wherein said natural material is chosen from horn, leather, wood and ivory from non-human animals, shell shells, and any one of their mixtures. 4. Composite material according to any one of claims 1 to 3, containing from 30 to 55% by weight of said particles, relative to the total weight of said composite material. 5. Method for preparing a composite material according to any one of claims 1 to 4, characterized in that it comprises a step of mixing particles of said natural material containing scleroproteins and said thermoplastic polymer. 6. Preparation process according to claim 5, according to which the particles of said natural material have dimensions between 100 and 500 μm. 7. A method of preparation according to any one of claims 5 to 6, comprising a step of shaping, in a shaping device, the material obtained in the step of mixing the particles of said natural material and said polymer . 8. Preparation process according to any one of claims 5 to 7, according to which the step of mixing the particles of said natural material and of said polymer is carried out in said shaping device. 9. Use of a composite material according to any one of claims 1 to 4 for the manufacture of an article of composite material. 10. Article made of composite material made of composite material according to any one of claims 1 to 4.