WO2012095569A1

WO2012095569A1 - Composition and method for manufacturing a rigid algal-matter material that is particularly usable as a substrate for printing

Info

Publication number: WO2012095569A1
Application number: PCT/FR2011/052610
Authority: WO
Inventors: Rémy LUCAS
Original assignee: Algopack
Priority date: 2011-01-14
Filing date: 2011-11-09
Publication date: 2012-07-19

Abstract

The invention relates to a composition obtained by mixing, with an aqueous solution, at least one powder including 5 to 15% by dry weight of a phycocolloid, 4 to 75% by dry weight of a filler agent, a gelling agent such as calcium sulfate, and a gelling control agent. The invention also relates to a method for manufacturing a rigid biodegradable material from said composition. According to the invention, such a composition includes, proportionally, 20 to 40 g of said powder per 60 g of said aqueous solution.

Description

Composition and process for the manufacture of a rigid material based on algal material, used in particular as a printing medium

1. Field of the invention

The technical field of the invention is that of materials incorporating organic material of natural origin.

More specifically, the invention relates to a composition and a process for the manufacture of a rigid material.

In the context of the invention, the term "rigid material" in its general meaning, namely a firm material, able to withstand deformation forces, having a high stiffness, and therefore very flexible.

The invention finds particular but not exclusively an application in the design of advertising and / or communication media, but also for example in the field of signage, tableware and decoration, furniture, or even in the manufacture of primary packaging, such as food trays, secondary packaging, such as cases or boxes for the packaging of cosmetic products, soundproofing and / or thermal insulation panels, and non-flammable panels and fire resistant.

2. State of the art

Many rigid objects are made of thermoplastic or thermosetting synthetic plastic material, because of the ease of shaping this raw material, its lightness, and its current low cost.

The cost of plastics, however, depends heavily on fluctuations in oil prices, which directly impacts the industrial production of rigid plastic objects. It is also expected to grow significantly in the coming decades due to the expected depletion of oil resources. Plastic waste can also be a source of long-lasting pollution and / or disfigure the landscape, if left in nature.

Known easy to form materials obtained from organic material, such as modified starch for example.

A disadvantage of these materials is that they are not suitable for making rigid objects that do not bend and resist deformation stresses. It is found that the rigid objects currently produced from these materials inevitably incorporate synthetic plastics to impart their rigidity, which reduces their interest.

Another disadvantage of these materials is that their life is limited to a few weeks or even a few months.

Another disadvantage of these materials is that they are sensitive to moisture.

These materials also have the disadvantage of being expensive.

The production of these materials also confiscates agricultural resources useful for the purpose of producing manufactured goods, to the detriment of food production for the population or for livestock, which is unsatisfactory.

3. Objectives of the invention

The invention therefore particularly aims to overcome the disadvantages of the state of the art mentioned above.

More specifically, the object of the invention is to propose a composition based on raw materials of natural origin, making it possible to manufacture a material of suitable rigidity.

An object of the invention is in particular, in at least one embodiment of the invention, to manufacture from such a composition a material that can substitute for a plastic material or cardboard.

Another object of the invention is to provide such a composition that is malleable and allows to produce monobloc objects of complex shapes. Another object of the invention is to provide such a composition which makes it possible to obtain a material having an aptitude suitable for degrading at least partially, which is bio-assimilable by the environment, and preferably in accordance with the European standard. EN-13432 or NFU 52001.

An object of the invention is, in at least one particular embodiment of the invention, to provide a composition making it possible, to a certain extent, to obtain an inert material, or in other words a material which is stable on a plane physico-chemical, vis-à-vis the action of moisture and / or fire for example.

An object of the invention is also to provide such a composition which leads to a light material.

Another object of the invention is, in a particular embodiment of the invention, to provide a composition for obtaining a printable material, and / or on which can adhere paints or varnishes suitable for direct food contact.

Yet another object of the invention is to provide a technique for manufacturing a rigid material from such a composition that is simple to implement, reliable, and low cost.

4. Presentation of the invention

The Applicant has found, surprisingly and unexpectedly, by seeking a solution that makes it possible to achieve these objectives, by mixing, in unprecedented proportions, an aqueous solution with a powder which can be used for example in the composition of self-gelling cosmetic masks. possible to obtain a moldable material becoming rigid after hardening.

To this end, the subject of the invention is a composition obtained by mixing at least one powder of the type comprising 5 to 15% by dry weight of a phycocolloid, 45 to 75% by dry weight of a filler, a gelling agent such as calcium sulphate and a control agent of the gelling, with an aqueous solution, in proportions of 20 to 40 g of said powder for 60 g of said aqueous solution.

The fact that this composition provides a rigid material and not a gel or an elastic material, could be explained at least in part by the unusually low proportion of aqueous solution added to the mixture.

The Applicant has further found that a more rigid material is obtained by increasing the proportion of powder in the mixture, within the unexpected limit of 40 percent of the weight of the composition.

In addition, the use of phycocolloid, that is to say hydrocolloids of algal origin whose resource is essentially renewable, advantageously provides substantial malleability to the composition before curing.

Advantageously, said powder comprises 0.1 to 3% by dry weight of a food preservative, preferably between 0.5 and 2% by dry weight of a food preservative, and for example 0.5%, 0, 7% or 1% by dry weight of a food preservative.

Thus, mold growth is prevented in the material made with this composition, which may alter the appearance and / or strength of this material. Such a food preservative may be for example sodium benzoate, or any other known mineral or organic food preservative, for example referenced in the list of fifty three food additives authorized at European level, commonly designated by a code of the form E2xx where xx is a number between 00 and 97, to prevent the alteration of organic matter under the action of microorganisms such as yeasts, molds and bacteria.

In addition, it should be noted that a weight percentage of important food preservative, and more precisely greater than 2 or 3%, is likely to confer brittleness to the material obtained after hardening. According to a particular aspect of the invention, said phycocolloid is an alkaline alginate.

It may in particular be a certified organic alginate by an authorized organism, such as for example Ecocert (registered trademark).

In other embodiments of the invention, it may be a carrageenan, an agar-agar, another type of known alginate, or a mixture of different types of phycocolloids.

In the context of the invention, this phycocolloid is advantageously extracted from marine algae or freshwater algae chosen from the family Chlorophyceae, Rhodophyceae and / or Phaeophyceae. Culture algae, drifting algae, or stranding algae are also suitable for the preparation of said phycocolloid.

These algae may for example be of the genus Laminaria, Fucus, Ascophyllum, Sargassum or Saccorhiza, and more specifically, species Fucus vesiculosus, Fucus serratum, and Laminaria elongata. It can also be considered to extract this phycocolloid green algae that invade parts of the coastline.

Alternatively, synthetic hydrocolloids may also be used.

According to an advantageous embodiment of the invention, said filler is formed of diatomaceous earth and / or kaolin.

The advantageous presence of inert filler agents with a low affinity for water, such as diatomaceous earth and / or kaolin, makes it possible to effectively disperse the phycocolloid grains in the mixture, which promotes the progressive solubility of these substances. grains and prevents the formation of agglomerates of poorly solubilized grains. Thus, after mixing, a homogeneous texture composition having a substantially smooth surface is obtained.

In a particular embodiment of the invention, said filler also comprises cellulose.

This gives a stronger fibrous material. In at least one particular embodiment of the invention, said powder further comprises 1 to 15%, and preferably 5 to 7%, by dry weight of dried and ground ulva.

It may be ulva of a single genus, for example of the genus ulva lactuca, or ulva mixed.

The Applicant has indeed found that the introduction of 1 to 15% ulva in the formulation of the powder makes it possible to improve the mechanical strength of the rigid material obtained after hardening.

It has also been observed that from a weight content of 7% on dry matter in ulva, the ability of the composition to harden and stiffen is reduced, and that beyond a content of 15% in ulva, this ability is strongly altered.

The introduction of ulves into the composition also advantageously makes it possible to reduce the cost price of the rigid material obtained.

The invention also relates to a method for manufacturing a rigid material comprising the following steps:

- Preparation of a composition capable of curing such as those described above obtained by mixing 20 to 40 g of a powder of the type comprising 5 to 15% by dry weight of a phycocolloid, 45 to 75% by dry weight a filler, a gelling agent such as calcium sulphate and a gelling control agent, with 60 g of an aqueous solution in proportions, comprising a step of homogeneous vacuum mixing of said composition;

forming a layer of at least three millimeters, and preferably at least five millimeters of said composition prepared;

- resting said layer for a suitable period, resulting in a hardening of said layer;

pressing said hardened layer for a predetermined duration comprising at least one step of absorbing excess liquid extracted from said pressed layer; - Dehydration of said pressed layer at a temperature less than or equal to 90 ° C, and in particular less than or equal to 80 ° C, for obtaining said rigid material.

It should be noted that within the scope of the invention, a suitable duration of resting is understood to mean a period of at least two minutes, and preferably from three to eight minutes depending on the composition prepared.

In particular embodiments of the invention, the dwell time may be for example 10, 15 or 20 minutes.

In addition, it is appropriate to adapt the pressing time according to the thickness and pressure applied to the layer. The Applicant has notably found that a pressing time of less than 24 hours is in all cases sufficient to extract the excess of liquid in the layer, when applied a distributed pressure greater than or equal to 0.2 N / cm ² .

For example to obtain a table stand, one can mix, under vacuum, about 300g of powder with 700g of distilled water for five minutes, until a homogeneous paste, pour a layer of forty millimeters of this paste in a mold and make it sit for seven minutes, then press it under a distributed pressure of 1 N / cm ² , and dehydrate it by applying three temperature steps at 35, 55 and 80 ° C for about four hours each.

The manufacturing method according to the invention is also suitable for the manufacture of objects of 70, 100, 150 or 200 millimeters thick, for example. For such objects the duration of pressing and dehydration is however greater, and can reach 24 hours, or even days.

It is noted that the formation of a layer of at least three millimeters, and preferably at least five millimeters, gives a satisfactory stability to it during the pressing and dewatering operations, and in particular prevents the appearance of microorganisms. cracks and / or unacceptable deformations. In addition, the dehydration temperature is advantageously limited to 80 ° C. in order to prevent the aqueous solution present in the material from boiling and may generate mechanical stresses that may cause this material to rupture.

During the step of forming a layer, it may advantageously be envisaged to agitate the layer, for example by means of a table or a vibrating needle, so as to evacuate the bubbles and air pockets that are trapped in and or under the layer, for example when pouring the composition gradually into a mold.

According to a particular aspect of the invention, said vacuum mixing is carried out over a period of 2 to 5 minutes.

This gives a homogeneous mixture free of air bubbles.

The Applicant has moreover observed that the more the quantity of aqueous solution is important in the composition, the more it is necessary to mix the powder and the aqueous solution for a long time to obtain a homogeneous paste.

Advantageously, the temperature of said aqueous solution used for the preparation of said composition is between 15 and 25 ° C, and preferably equal to 20 ° C.

The Applicant has indeed found that in this temperature range, it is possible to control the curing speed and the rate of shrinkage of the dough, so as to prevent the paste from deforming in an inappropriate manner by hardening, and by example in a highly anisotropic manner, and / or that the hardened paste is fragile.

In addition, the composition of aqueous solutions whose concentration of minerals, and in particular of calcium, and of trace elements is small, such as demineralised water or distilled water, is preferentially retained to form the composition.

In at least one particular embodiment of the invention, it is possible to store said layer, after pressing, in the open air and at a temperature of between 20 ° C. and 30 ° C., and preferably under hygrometry. controlled, for about 24 hours to 72 hours, and for example for 48 hours if it is a plate 20 millimeters thick. During this storage in the open air, the plate may for example be deposited on a grid, to allow air circulation around each of its faces.

It is noted that during such a step of storage in the open air, there is a shrinkage of 3% to 10% on the thickness plate sizes initially comprised between 25 and 40 millimeters, for example.

Preferably, said dehydration step exhibits exposure to a plurality of temperature steps.

Thus, the residual water is gradually removed from the material without altering the chemical bonds formed within the material, and it is likely that this is also done by catalyzing various chemical reactions within the material.

Said dehydration step may be carried out in a dehydrator or an oven under temperature and, preferably, under controlled hygrometry, and for example a temperature of 75 ° C. and a hygrometry of 20%, in order to obtain a drying of the heart.

In a particularly advantageous embodiment of the invention, said layer is returned during said dehydration step.

Preferably, said layer is returned several times.

This prevents the layer of material from forming a curve.

The invention further relates to the use of a rigid material made from a manufacturing method such as those described above as a printing medium, or as acoustic and / or thermal insulation. It also relates to its use for the manufacture of a fire and / or fireproof device, a piece of furniture or a food tray.

5. List of figures

Other features and advantages of the invention will emerge more clearly on reading the following description of embodiments of the invention, given by way of simple illustrative and non-limiting examples, and the appended drawings in which: FIG. 1 is a schematic representation of the steps of a method for manufacturing a rigid material according to the invention;

FIG. 2 represents a printed plate made of rigid material obtained from a composition according to the invention, in a schematic form.

6. Detailed description of an embodiment of the invention

6.1. Example of embodiment of the invention

The formulation of a low granulometric powder used to form a composition according to the invention when it is mixed with demineralised water in proportions of 30 g is given by way of example and without limitation. of powder for 60g of water. The amounts of each constituent of this powder are given in percent by weight in the table below.

Example 1

The description below describes a manufacture of a rigid material plate in A4 format in the laboratory. The same modes of operation may be the basis of industrial manufacture. FIG. 1 is a block diagram of the steps of a method of manufacturing a rigid material according to the invention from the aforementioned composition, in block diagram form.

A dose of premixed powder, the formulation of which was specified above, is taken from a bucket and poured into the vessel of a vacuum mixer (step 11). Two doses of demineralised water at 20 ° C. are then added to the container (step 12), and the powder and the water are mixed vigorously for four minutes to obtain a liquid paste of homogeneous, free texture. powder lumps (step 13).

Of course, it is conceivable to reverse the order of steps 11 and

12.

A layer of this paste of a thickness of five millimeters is poured into a mold whose internal dimensions correspond to those of a sheet A4, which is allowed to rest for five minutes so as to allow the setting of the paste in the mold. mold (step 14).

In variants of this particular embodiment of the invention, it may of course be envisaged to adapt the resting time of the paste depending on the temperature, the minerality of the aqueous solution, and / or or products incorporated in the composition that affect setting time.

After setting, the hardened paste is taken from the mold, which is now in the form of a white plate. Note that this plate may have a surface of non-smooth appearance, and for example embossed, depending on the shape of the mold.

In a step 15, the plate is disgorged by wrapping it with a water-absorbing material, such as a sheet of blotting paper for example, and keeping it compressed in a press under a pressure of 0, 7 N / cm ² for four hours. In this step, care is taken to regularly replace the absorbent material which saturates rapidly with the water exuding from the plate. This pressing step avoids deformation, and in particular that the surface of the plate adopts an irregular or bumpy appearance, during a subsequent dehydration step 16.

In an alternative of this embodiment of the invention, it may also be provided to apply a greater pressure on the plate to accelerate the migration of the residual water out of the plate.

Then, in a step 16, dehydration of the disgorged plate in a dehydrator provided for this purpose, to greatly reduce the moisture content in the plate.

In the dehydrator, the plate is exposed at a first temperature stage of 3 hours at 40 ° C. (step 161), then at a second temperature stage at 80 ° C. for a duration of 3 hours (step 162). and turn the plate every hour to prevent it from forming.

To produce advertising media from this plate, a series of fifteen identical advertising motifs 22 are printed in four-color process in a step 17 on the rigid plate obtained after passing through the dehydrator by a printing method known per se, such as by example by pad printing, screen printing or digital ink jet printing. This printed plate 21 is shown in FIG.

In a variant of this embodiment of the invention, at least a portion of the plate obtained by the manufacturing method according to the invention can be coated with an adhesive printed film, and / or a varnish to reinforce the ability to contact food directly and meet the criteria of the IFS version 5 certification, avoiding in particular the deposition of microscopic particles, for example in the form of dust, and preventing catalytic effects that may change the taste of food.

In a step 18, this printed plate is machined using an aluminum bur without the use of lubricant, so as to obtain fifteen identical key-ring pendants, which are covered with a film of a lacquer. biodegradable waterproof to protect them from rain and splashing water.

It can be seen that the rigidity of the plates obtained according to the invention makes it possible to respect shape tolerances of less than 2 millimeters, and most often less than 0.3 millimeters, during milling.

6.2. Other examples of powders that can be used in a composition according to the invention

Three other examples of formulation of a powder that can be used in a composition according to the invention are detailed in the tables below.

Example 2

Product% by weight

sodium alginate 11

kaolin 64

(agent of charge)

calcium sulfate 16 (gelling agent)

tetrasodium pyrophosphate 7.5

(control agent of gelation)

food preservative 1.5

Example 3

Product% by weight

sodium alginate diatomaceous earth 49 (charging agent)

calcium sulphate 24 (gelling agent)

tetrasodium pyrophosphate 10

(control agent of gelation)

food preservative 2 Example 4

6.3. Other features and advantages of the invention In variants of the embodiments of the invention described above, it may also be provided:

substituting carrageenan or agar-agar for the alginate included in the powder formulation;

incorporating pigments or dyes into the powder or aqueous solution to dye the composition in the mass; to introduce 1 to 15% by dry weight of milled and dried ulva and preferably 5 to 7% of ulva in the powder;

using a filler comprising an organophilic clay selected from the group of bentonites, hectorites or montmorillonites;

embedding electronic components at least partially in the composition during the formation of the plate;

depositing a vinyl-based adhesive film or latex and / or reinforced with fiber, or a layer of an acrylic varnish suitable for direct food contact on a rigid material obtained by the manufacturing method according to the invention. In another variant, it may be envisaged, without departing from the scope of the invention, to pour the paste obtained after mixing a composition according to the invention in a footprint to give the rigid material a final shape.

Claims

1. Composition capable of hardening for the manufacture of a rigid material, obtained by mixing at least one powder comprising 5 to 15% by dry weight of a phycocolloid, 45 to 75% by dry weight of a filler , a gelling agent such as calcium sulphate and a gelling control agent, with an aqueous solution, characterized in that it comprises from 20 to 40 g of said powder for 60 g of said aqueous solution in proportions.

2. Composition according to claim 1, characterized in that said powder comprises 0.1 to 3% by dry weight of a food preservative, preferably 0.5 to 2% by dry weight of a food preservative.

3. Composition according to any one of claims 1 and 2, characterized in that said phycocolloid is an alkaline alginate.

4. Composition according to any one of claims 1 to 3, characterized in that said filler is formed of diatomaceous earth and / or kaolin.

5. Composition according to claim 4, characterized in that said filler also comprises cellulose.

6. Composition according to any one of claims 1 to 5, characterized in that said powder further comprises 1 to 15% by dry weight, and preferably 5 to 7%, ulva dried and crushed.

7. A method of manufacturing a rigid material, characterized in that it comprises the following steps:

- preparing a curing composition according to any one of claims 1 to 6 comprising a step of homogeneously vacuum mixing said composition;

forming a layer of at least three millimeters, and preferably at least five millimeters, of said composition prepared;

- resting said layer for a suitable period, resulting in a hardening of said layer; pressing said hardened layer for a predetermined duration comprising at least one step of absorbing excess liquid extracted from said pressed layer;

dehydration of said pressed layer at a temperature of less than or equal to 80 ° C., making it possible to obtain said rigid material.

8. Manufacturing process according to claim 7, characterized in that said vacuum mixture is carried out over a period of 2 to 5 minutes.

9. The manufacturing method according to any one of claims 7 and 8, characterized in that the temperature of said aqueous solution used for the preparation of said composition is between 15 and 25 ° C, and preferably equal to 20 ° C.

10. The manufacturing method according to any one of claims 7 to 9, characterized in that said dehydration step exhibits exposure to a plurality of temperature steps.

11. The manufacturing method according to any one of claims 7 to 10, characterized in that said layer is returned during said dehydration step.

12. Use of a rigid material made from a process according to one of claims 7 to 11 as a printing medium.

13. Use of a rigid material made from a method according to one of claims 7 to 11 as acoustic and / or thermal insulation.

14. Use of a rigid material made from a process according to one of claims 7 to 11 for the manufacture of a fire and / or fire barrier device.

15. Use of a rigid material made from a method according to one of claims 7 to 11 for the manufacture of a piece of furniture.

16. Use of a rigid material made from a process according to one of claims 7 to 11 for the manufacture of a food tray.