MATERIALS AND ARTICLES PREPARED FROM POLYSACCHARIDES

Abstract

Material for the manufacture of compostable articles, comprising the following components in the proportions: 65-95% polysaccharide source comprising at least 80% starch; 5-35% of at least two polyols; 0-10% of at least two additives; q.s. water; the percentages being mass percentages expressed in relation to the total mass of the material. Figure 1.

Description

Title of the invention: MATERIALS AND ARTICLES PREPARED FROM POLYSACCHARIDES

[0001] The present invention relates to the field of materials that can be prepared from polysaccharides such as starch, and relates more particularly, but not exclusively, to the use of these materials to prepare disposable articles such as single-use cutlery. State of the art

[0002] The manufacture of recyclable products meets the socio-economic objectives of our time, and aims to produce eco-responsible products, that is to say products whose life cycle impacts the environment as little as possible and which fit perfectly into a logic of sustainable development.

[0003] Among eco-friendly products, compostable products are highly valued. Products that best meet this recycling property through composting are those that incorporate bio-based inputs. Among bio-based inputs, carbohydrate inputs such as polysaccharides occupy a prominent place.

[0004] Such carbohydrate inputs are known from patent application FR3082408A1 for the preparation of biodegradable straws, particularly from starch fibers. The process described in application FR3082408 for manufacturing straws remains limited to the use of natural fibrous materials, which, after being reduced to powder, are transformed by extrusion into drinking straws. However, implementing the extrusion process from starch powder has the disadvantage of being poorly suited to the shaping or recycling of more complex articles, such as forks.

[0005] Application EP 4223127 A1 describes the use of a vegetable starch source for the preparation of baked foods, and does not provide for the use of polyols, apart from the use of xylitol which is required only as a sweetening agent.

[0006] EP 3910005 A1 describes the combined use of a starch source and one or two polyols, selected from glycerin and sorbitol, for the preparation of granules used in the manufacture of compostable articles. However, the levels of starch incorporated into the product remain low, making the products less compatible with the objective of using only bio-based inputs and thus resulting in the manufacture of more readily compostable articles.

[0007] The present invention aims at preparing a stable and homogeneous material incorporating a rate greater than 65%, or even 70%, of at least one bio-based input of natural origin, in order to enable the manufacture of compostable objects, while maintaining a ease of manufacturing linked to the quality of the raw materials used in the manufacturing process. Description of the invention

[0008] To overcome the drawbacks of the aforementioned prior art, the present invention relates to a material for the manufacture of compostable articles, comprising the following components in the proportions: 65-95% polysaccharide source; 5-35% of at least two polyols; 0-10% of at least two additives; qsp water; The percentages being mass percentages expressed relative to the total mass of the material, said polysaccharide source comprising at least 80% of the given starch relative to the total mass of polysaccharide (qsp denoting the acronym "quantity sufficient to reach 100%"). Preferably, said polysaccharide source comprises at least 85% starch, advantageously 90%, or even 95%.

[0009] The inventors discovered, quite unexpectedly, that the combined use of several polyols increased the quantity of polysaccharides and facilitated the manufacture of compostable objects by improving their compostability. Preferably, at least one of the two polyols is liquid.

[0010] The polysaccharide source of the material according to the invention is preferably selected from at least one of the following starches: wheat starch, potato starch, pea starch, cassava starch and a hybrid corn starch, which hybrid starch is made up almost entirely, or even exclusively, of amylopectin and amylose.

[0011] The term "polysaccharide" in the context of the invention refers to entities sometimes called glycans, polyosides, polyholosides or complex carbohydrates, which are macromolecular compounds of the carbohydrate family consisting of several sugars linked together by glycosidic bonds.

[0012] In the context of the invention, the term "polysaccharide source" defines an agricultural material containing at least 98% polysaccharide and is advantageously a starch selected from among the starches listed previously in the context of the invention. A polysaccharide refers to macromolecules formed by the polymerization of simple carbohydrates or monosaccharides, sugars; they are biopolymers formed by the union of a large number of high molecular weight monosaccharides of a carbohydrate nature (polyoside) exhibiting thickening, stabilizing, or gelling properties depending on the size of the macromolecule. Polysaccharides are biodegradable and water-soluble. The main polysaccharides are starch, glycogen, inulin, cellulose, hemicelluloses, and pectins. It can This also includes cellulose gum and gum arabic. Preferably, the material comprises cellulose, preferably in a content of 5 to 15% by mass of said material according to the invention, and advantageously it is food-grade cellulose.

[0013] Polysaccharides can be linear (e.g., alginic acid, cellulose) or branched (e.g., starch, glycogen, polysaccharides of tragacanth, arabic, and sterculia gums). Polysaccharides can be involved in bonds with protein fragments (e.g., peptidoglycans of the bacterial cell wall, proteoglycans, glycoproteins). Many polysaccharides exhibit a strong affinity for water (manifesting, depending on the case, as the formation of viscous solutions, gelation, or swelling) directly related to their various uses. Homopolysaccharides can be linear (amylose, cellulose, chitin) or branched (amylopectin, glycogen). Heteropolysaccharides are classified according to the nature of the principal glycosidic units that compose them. Araboxylans are mixed polymers of arabinose and xylose. The same principle applies to classifying galactoarabans, galactomannans, etc...Heteropolysaccharides are generally formed from only a few types of monosaccharides that follow each other in sequence according to a repeating pattern. Branching is quite common in heteropolysaccharides, but it follows simple patterns.

[0014] Starches are carbohydrate compounds made up of two glucose polymers: amylose and amylopectin.

[0015] In the context of the invention, the starch used is preferably a native starch, a modified starch and / or a stabilized starch.

[0016] For the purposes of the present invention, the term "native starch" means starch derived from at least one cereal and / or tuber, in its original state, without any treatment, transformation, addition or modification having been applied to it, as opposed to modified or stabilized starch.

[0017] For the purposes of this invention, the term "modified starch" refers to starches that have undergone various physical, chemical, and / or enzymatic treatments that give them new functional properties. Crosslinking involves the formation of bridges between the starch chains to make them more resistant to temperature, pH, and shear stress (pumping, agitation). Crosslinking increases the thickening power of starches rich in amylopectin.

[0018] For the purposes of the present invention, the term "stabilized starch" refers to starch that has undergone stabilization consisting of a treatment that allows the partial substitution of groups responsible for the retrogradation of starches over time, thus preventing syneresis. Stabilization also allows a translucent gel to be maintained during storage.

[0019] For the purposes of the invention, a "hybrid starch" is a starch comprising essentially, that is to say, more than 95%, or even more than 97% and even more than 98.5%, amylopectin and amylose. Advantageously, the hybrid maize starch used in the context of the present invention comprises more than 98.5% amylopectin expressed as a mass percentage relative to the total mass of starch.

[0020] Preferably, the starch used in the material within the framework of the present invention preferably comprises more than 70% amylopectin, the percentage being a mass percentage expressed in relation to the total mass of starch source.

[0021] The starch used for preparing the material according to the invention advantageously comprises an amylose content of 35% or less and an amylopectin content of more than 70%, expressed as mass percentages relative to the total mass of starch. Table 1 describes the principal starches of interest with their respective amylose and amylopectin fractions. In some cases, however, since the starch of the material according to the invention may be amorphous, said amorphous starch may also comprise between 50% and 80% amylopectin and between 10% and 40% amylose.

[0022] Table 1. Starch Amylose Amylopectin Regular maize 28 72 Waxy maize 1 99 Wheat 26 74 Potato 23 77 Smooth peas 3 5 65

[0023] Preferably, the material according to the present invention comprises at least three polyols.

[0024] In the context of the invention, the term "polyol" defines an organic compound comprising several hydroxyl groups (-OH), and having the general chemical formula CnH2n+2On. Examples of polyols include (the terms in parentheses being equivalent): Glycerol (glycerin), Erythritol, Xylitol, Arabitol (lyxitol), Ribitol (adonitol), Sorbitol (gulitol), Dulcitol (galactitol), Mannitol, Volemitol, Maltitol, Isomaltitol, and Lactitol (lactositol). Preferably, the polyol selected from sorbitol, glycerol, and mannitol.

[0025] Preferably, the additives in the material according to the invention are selected from the following ingredients: an organic acid, preferably stearic acid, and silica. Advantageously, the additive is bio-based and the overall additive content is between 15 and 30%, the percentages being mass percentages expressed relative to the total mass of the material. Advantageously, among the additives, the material comprises 20 to 25% of at least one thickener expressed relative to the total mass of the material.

[0026] Preferably, the organic acid is a natural acid, that is to say, it is obtained directly from the natural environment without chemical synthesis and is defined as a saturated lipid of vegetable origin extracted mainly from cocoa and shea butter, as well as coconut oil. Stearic acid falls into the category of acids that can be natural acids.

[0027] Waxes (camauba, etc.), talc, magnesia (MgO), lecithin, etc. can also be used as additives.

[0028] The present invention also relates to a granule obtained from the material described above in the context of the present invention. The granules are advantageously thermoplasticized starch (TPS) granules.

[0029] The present invention also relates to an article comprising the material according to the invention, said article preferably being selected from cutlery, tableware and preferably food packaging.

[0030] Preferably, the article is selected from non-durable articles, semi-durable articles and durable articles.

[0031] Non-durable articles refer to single-use items, such as disposable or reusable tableware, or compostable, eco-friendly primary food packaging for the food service industry: cutlery, cups, boxes. Durable articles are fully recyclable items with recycling streams available. Non-durable articles may also include bags and utensils other than the aforementioned tableware.

[0032] Semi-durable articles are reusable articles, secondary packaging: recyclable and reusable packaging.

[0033] More particularly, the article according to the invention is intended for multiple uses such as single-use articles (disposable or reusable tableware), primary packaging (ecological and eco-responsible food, compostable (cutlery, cups, boxes) secondary packaging (recyclable and reusable packaging).

[0034] Other areas of use are also possible, for example: gardening, agriculture, automotive parts, etc.

[0035] The present invention also relates to a method for preparing a material as described above within the scope of the invention, comprising the following steps: a- mix at least one polysaccharide powder and possibly at least one other solid powdered component chosen from a polyol and an additive;

[0036] b- place the mixture obtained in a turbo mixer, add liquid components, including at least one polyol and operate to obtain a homogeneous mixture;

[0037] c- place in an oven at a temperature > 100 °C for at least 1 hour until total impregnation is obtained;

[0038] d - adjust the amount of water needed to obtain a relative humidity between 10 and 20%;

[0039] e - optionally store the mixture obtained in step d- in a humidity-controlled chamber. Step c- further improves the impregnation of the solids and results in the breakdown and plasticization of polysaccharides and branched polysaccharides that may be contained in the additives.

[0040] The present invention also relates to a process for manufacturing thermoplasticized starch (TPS) granules, in which the material according to the invention is incorporated into an extruder, preferably a twin-screw extruder, and undergoes an extrusion-granulation process at a progressive temperature from 120 to 180°C and with a specific mechanical energy input of 90 to 250 kWh / t, to obtain granules as described above in the context of the invention. The progressive temperature variation is preferably carried out over an interval of at least 15 minutes with a screw rotation speed greater than 100 rpm. Advantageously, the material used in the granule manufacturing process comprises more than 70% starch, and the granules obtained are thermoplasticized starch (TPS) granules.This process ensures strong cohesion between several linear or branched polysaccharides, particularly those involving polysaccharides like cellulose or gum arabic, and other components of the material, resulting in a product made up of natural macromolecules based on polysaccharides. A specific mechanical energy input of 90 to 250 kWh / t is required to break down the granular structure.

[0041] The present invention also relates to a method for producing articles as described above within the scope of the invention, wherein the granules according to the invention undergo a forming step, preferably by the plastic injection technique in which the temperature of the material is greater than 120 °C, and then the resulting material is transferred into tooling cooled by recorded pressures pressures of 90 or higher, or even 100 bar; and a moisture content greater than 0.8%. Cooling is preferably carried out at a temperature below 25°C.

[0042] The present invention is also described in the detailed description that follows, with reference to the experimental part which details certain embodiments by means of examples, given only by way of illustration and which should not be considered limiting, and to the figures which are also referred to in the part that follows. Experimental section

[0043] Protocol and preparation of the material

[0044] Preparation of material F51

[0045] The first step is the production of a homogeneous powdered premix by homogenizing the solids together: wheat starch, sorbitol (white solid), stearic acid and powdered silica in a turbo mixer for 3 to 8 minutes at rotation speeds between 200 and 5 rpm. The liquids are then added: water and glycerol (clear liquid).

[0046] Following this premixing, relative humidity measurements are taken and the level is adjusted between 10 and 20%. A humidity-controlled chamber may be used for storing the material.

[0047] Material F51 comprises, before adjustment with water, the following ingredients: Ingredient % by mass Wheat starch 72.6 Glycerol 11.8 Sorbitol 11.8 Stearic acid 2.8 Silica 0.9

[0048] Wheat starch can be replaced interchangeably by corn or potato starch. Stearic acid can be replaced by carnauba wax or cellulose.

[0049] Preparation of material F 78

[0050] The same method as that described for the preparation of F51 is implemented, in addition a third polyol, mannitol, is added in the form of a white powder.

[0051] Material F78 comprises, before adjustment with water, the following ingredients: Ingredient % by mass Wheat starch 71.1 Glycerol 8.3 Sorbitol 8,3 Mannitol 8,3 Stearic Acid 3 Silica 1

[0052] Preparation of material F 81

[0053] The same method as that described for the preparation of F51 is implemented. The lecithin in powder form is mixed with the other powders in the first step.

[0054] The material F 81 _ before water adjustment comprises the following ingredients: Ingredient % by mass Wheat starch 68 Glycerol 12.5 Sorbitol 12.5 Lecithin 3 Stearic acid 3 Silica 1

[0055] Comparative examples

[0056] Preparation of material F94

[0057] The same protocol as that described for the preparation of F51 is implemented; the ingredients used are listed below.

[0058] The F 94 material before water adjustment comprises the following ingredients: Ingredient % by mass: Starch 45, Glycerol 12.5, SA 3, Silica 1, Sorbitol 12.5, Powdered cellulose 26

[0059] Note: The starch present in small quantities is extruded correctly, but does not allow the production of granules to ensure its transformation: friable and gelatinous in the presence of moisture.

[0060] Preparation of material F93

[0061] The same method as that described for the preparation of F51 is implemented, with the addition of Guar gum in order to evaluate its impact compared to the examples according to the invention.

[0062] The F 9 3 material before water adjustment comprises the following ingredients: Ingredient % by mass: Starch 45, Glycerol 10 SA 3, Silica 1, Sorbitol 10, Guar 25, Water 10

[0063] Note: this formula containing Guar gum, with a low starch content, has been tested and a large amount of water (20%) had to be added to the hopper to successfully extrude it; this type of formulation is too soft, gelatinous in the presence of external humidity and does not allow for the production of granules for injecting single-use parts.

[0064] Protocol and preparation of granules

[0065] Process for manufacturing thermoplasticized starch (TPS) granules:

[0066] This process ensures cohesion between the components and the linear or branched polysaccharide(s), such as cellulose or gum arabic, present in the material, which leads to obtaining a product made up of natural macromolecules based on polysaccharides.

[0067] Thanks to the process according to the invention; the plasticizer content, the thermal energy (heating) and the mechanical energy (rotation and profile of the screw(s)) are combined in a very interdependent manner, while controlling the rheology and therefore the viscosities involved, including rheopexy.

[0068] The temperature ranges and specific mechanical energy transmitted are preferably between 100 and 180°C and between 90 and 250 kWh / t, respectively. The relative contribution of each of these parameters is determined to obtain granules usable in the thermoforming techniques used in plastics processing, in particular injection, transfer or compression, described above.

[0069] Extrusion-granulation (a classic technique for (thermo)mechanical transformation and shaping of polymers) by which a material is compressed in a screw whose profile ensures the shear and temperature necessary to obtain the cohesion and gelation in order to generate the desired molecular structure of the material enabling the manufacture of articles by thermoforming.

[0070] The material according to the invention undergoes the following transformation steps:

[0071] - the powdered material is introduced into the barrel of the extruder, preferably twin screws via the hopper.

[0072] - the tooling used is a twin-screw extruder with a diameter of 25 mm and a length of 700 mm equipped with Scamex® brand shear zones. More specifically, the extruder is equipped with a die having the cross-section of the extrudate which must be cooled and granulated by a crusher which transforms the profile into a tube, pipe, or plate, into dried and manageable granules.

[0073] The die used in the extruder alternately comprises sections including shearing means and sections including material stretching means. Such a die is shown in [Fig. 1], with a detailed view in [Fig. 2].

[0074] A zone-by-zone temperature profile is displayed to melt and plasticize the powdered material before it is extruded into filaments, air-cooled, then ground and bagged into airtight bags. Typical temperature profiles of the sheath for producing filaments to be granulated:

[0075] -between 125 to 150°C; -with an outlet temperature between 125 and 150°C; -the rotation speed is between 100 and 200 rpm; and -the measured torque is between 40 and 95%.

[0076] Protocol and preparation of compostable articles

[0077] Method for manufacturing the articles:

[0078] The forming is carried out by injection with a press comprising cavities using dedicated tooling and injection sprues.

[0079] The press is an electric or hydraulic press, the point is the control of the heating temperatures in the transfer, and that of the tooling maintained at a temperature below 25°C.

[0080] The moisture content of the granulated material is controlled and must be greater than 0.8%. Molding is carried out by setting the tool to 170°C and 150 bar, or 180°C - 90 bar hydraulic pressure.

Claims

Demands

1. Material for the manufacture of compostable articles, comprising the following components in the proportions: 65-95% polysaccharide source; 5-35% of at least two polyols; 0-10% of at least two additives; qsp water; the percentages being mass percentages expressed in relation to the total mass of the material; said polysaccharide source comprising at least 80% given starch in relation to the total polysaccharide mass.

2. Material according to claim 1, wherein the polysaccharide source is selected from at least one of the following starches: wheat starch, potato starch, pea starch, cassava starch and a hybrid maize starch.

3. Material according to claim 2, wherein the starch preferably comprises more than 70% amylopectin, the percentage being a mass percentage expressed relative to the total mass of starch source.

4. Material according to any one of claims 1 to 3, wherein the material comprises at least three polyols, preferably selected from sorbitol, glycerol and mannitol.

5. Material according to any one of claims 1 to 4, wherein the additives are selected from the following ingredients: an organic acid, preferably stearic acid, and silica.

6. Granule obtained from the material according to any one of claims 1 to

7. d J. Article comprising the material according to any one of claims 1 to 5, said article preferably being selected from cutlery, tableware and packaging preferably of food.

8. A method for preparing a material according to any one of claims 1 to 5, comprising the following steps: a- mixing at least one polysaccharide powder and optionally at least one other solid powdered component selected from a polyol and an additive; b- place the mixture obtained in a turbo mixer, add liquid components, and operate to obtain a homogeneous mixture; c- place in an oven at a temperature > 100 °C for at least 1 hour until total impregnation is achieved; d - adjust the amount of water used to obtain a relative humidity between 10 and 20%; e - possibly store the mixture obtained in step d- in a controlled humidity chamber.

9. A method for manufacturing granules according to claim 6, wherein the material according to any one of claims 1 to 5 is incorporated into an extruder, preferably a twin-screw extruder, and undergoes an extrusion-granulation treatment at a progressive temperature of 120 to 180°C and with a specific mechanical energy transmitted of 90 to 250 kWh / t.

10. A method for producing articles according to claim 7, wherein the granules according to claim 6 undergo a forming step, preferably by the plastic injection technique in which the temperature of the material is greater than 120 °C, then the material obtained is transferred into a tooling cooled by recorded pressures greater than or equal to 90, or even 100 bars and the moisture content greater than 0.8%.

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