Biodegradable thermoplastics based on casein and / or caseinates

Abstract

The present invention relates to a biodegradable thermoplastic based on casein and / or caseinate. In particular, the present invention relates to a biodegradable thermoplastic comprising: a) 50% to 80%, preferably 55% to 70% of casein and / or caseinate; b) 4% to 12%, preferably 5% to 11% of water; c) 10% to 35%, preferably 15% to 28% of at least one plasticizer different from b); d) 0.1% to 8%, preferably 1% to 4% of a hydrophobic agent; e) 0.5% to 6%, preferably 2% to 4% of at least one surfactant.

Description

Technical Field

[0001] The field of the invention is that of biodegradable and biosourced thermoplastics, more particularly that of thermoplastics based on casein and / or caseinates.

[0002] In particular, the present invention relates to a biodegradable thermoplastic comprising:

[0003] a) 50% to 80%, preferably 55% to 70%, casein and / or caseinate;

[0004] b) 4% to 12%, preferably 5% to 11% water;

[0005] c) 10% to 35%, preferably 15% to 28%, of at least one plasticizer different from b);

[0006] d) 0.1% to 8%, preferably 1% to 4%, of a hydrophobic agent;

[0007] e) 0.5% to 6%, preferably 2% to 4%, of at least one surfactant.

[0008] The subject matter of the invention is also biodegradable thermoplastics in various forms, in particular in the form of pellets constituting raw materials for conversion into various articles, such as films, threads or moulded articles.

[0009] The invention also relates to packaging films obtained from this thermoplastic, more particularly packaging for absorbent products, such as detergent bars, made from this film. Background Art

[0010] The decrease in non-renewable resources such as petroleum and the increase in pollution associated with these resources are driving the development of alternative solutions that are fungible, less polluting and more environmentally friendly.

[0011] In the field of plastics, new biodegradable materials are being developed. These new materials can be made from polymers of natural origin or synthetic polymers. For example, plant proteins, such as corn protein and soy protein, or animal proteins can be used to make packaging.

[0012] Among animal proteins, casein is particularly attractive. In fact, this protein from milk is available in large quantities, and casein-based films have good clarity and good biodegradability.

[0013] Document FR 2963013 describes biodegradable thermoplastic pellets based on casein and / or caseinates and a process for their preparation. These pellets can be used to make thermoplastic films. However, these thermoplastic films are not easy to use industrially. For example, the films are sometimes sticky; therefore, it is difficult or even impossible to unroll the roll of film using industrial equipment, since the layers stick to each other. Moreover, when these films are used to package detergent bars or when these bars are stored under conditions of low relative humidity (for example 30%), they sometimes become brittle and tear, so that they no longer fulfil their packaging function.

[0014] Purpose

[0015] Under such circumstances, the present invention is intended to meet at least one of the following objects.

[0016] One of the basic objects of the present invention is to provide biodegradable thermoplastics based on casein and / or caseinates which can be used industrially and in particular can be converted into intermediate or final products in simple or complex shapes by techniques such as injection molding, extrusion, film blowing, solvent casting, thermoforming or mechanical processing.

[0017] Another basic object of the present invention is to provide a biodegradable thermoplastic film based on casein and / or caseinate which can be rolled up and unrolled.

[0018] Another basic object of the present invention is to provide a biodegradable thermoplastic film based on casein and / or caseinate which can be used in particular for packaging absorbent products such as detergent bars. Summary of the invention

[0019] Firstly, the present invention relates to a biodegradable thermoplastic, characterized in that it comprises:

[0020] a) 50% to 80%, preferably 52% to 75%, more preferably 55% to 70% casein and / or caseinate;

[0021] b) 4% to 13%, preferably 4.5% to 12%, more preferably 5% to 11% water;

[0022] c) 10% to 35%, preferably 12% to 32%, more preferably 15% to 28% of at least one plasticizer different from b);

[0023] d) 0.1% to 8%, preferably 0.5% to 6%, more preferably 1% to 4% of a hydrophobic agent;

[0024] e) 0.5% to 6%, preferably 1% to 5%, more preferably 1.5% to 4.5% of at least one surfactant.

[0025] Biodegradable thermoplastics as described above can be used in industry.In fact, films can be obtained with this material, which can be rolled into a roll and then easily unrolled.

[0026] This suitability for winding and unwinding at industrial rates is a key parameter for films made from casein thermoplastic and according to the invention.

[0027] Furthermore, the film can be used to package various products, for example hygroscopic products such as detergent bars, since the film maintains its integrity even when the bars are stored under conditions of low relative humidity.

[0028] Furthermore, in some cases, the prepared film is edible. Thus, it can be used in various applications such as packaging food, ingredients or additives, edible packaging, single doses of food ingredients to be dissolved, and single doses of food additives. It can also be used as separator paper. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A and Figure 1B is a photograph of a roll of film according to Comparative Example 1 that could not be unrolled.

[0030] Figure 2A , Figure 2B and Figure 2C is a photograph of a roll of film according to Comparative Example 4 that can be unrolled.

[0031] Figure 3A and Figure 3B is a photograph of a detergent block packaged in a film according to Comparative Example 1 after five days of packaging testing.

[0032] Figure 4 is a photograph of a detergent block packaged in a film according to Comparative Example 4 after five days of packaging testing.

[0033] Photo 5A and Photo 5B are photographs of detergent bars packaged in the printed film according to Example 5 after five days of packaging testing.

[0034] Figure 6 is a photograph of the unwinding test apparatus used in the Examples to evaluate films made from casein thermoplastic.

[0035] Photographs 7A and 7B are photographs of parts obtained from biodegradable thermoplastic pellets according to Example 4 by injection molding.

[0036] definition

[0037] “Thermoplastic” is understood to mean, for example, a material which becomes ductile and foldable above a given glass transition temperature Tg, but becomes rigid again below this Tg; these transitions are reversible.

[0038] "Biodegradable" is understood to mean a material that can be decomposed under the action of microorganisms (e.g. bacteria, fungi, algae, etc.). As a result of this decomposition, water, CO2 and / or methane are formed as well as by-products that may be non-toxic to the environment (e.g. residues, new biomass). For example, it relates to biodegradable materials according to the European EN NF 13432 standard.

[0039] “X to Y” should be understood as, for example, limiting x and y to be included in the interval [X, Y].

[0040] "Water-soluble" is understood to mean, for example, a substance that dissolves in water. The water solubility of the film can be measured by the following method: a piece of film (5 cm x 5 cm, molded cut) is fixed on a glass slide and then immersed in a 1000 mL beaker containing 600 mL of distilled water and stirred at 300 RPM with a magnetic bar at 20°C. The time for the formation of pores in the film is measured. The disintegration of the film leads to the formation of film particles. The test lasts for five minutes and at the end the particles are passed through a 0.5 mm sieve to verify the size of the particles. When there are no particles in the sieve, the film is considered to be water-soluble.

[0041] A "plasticizer" is understood to mean, for example, a substance which lowers the glass transition temperature Tg of a material.

[0042] "Detergents" are understood as meaning, for example, compositions having cleaning properties. Among detergents, there may be listed products in powder or compacted powder form for dishwashers and laundry.

[0043] "Hydrophobic" is understood to mean, for example, compounds which have a low affinity for water and tend to be insoluble in water. Typically, this relates primarily to non-polar compounds.

[0044] "Hydrophilic" is understood to mean, for example, a compound which has an affinity for water and tends to dissolve in water. Typically, it relates to compounds having polar groups which are able to form hydrogen bonds.

[0045] "Surfactant" is understood to mean, for example, amphiphilic molecules, ie molecules having both hydrophilic and hydrophobic properties.

[0046] "HLB" is understood to mean, for example, the hydrophile-lipophile balance. The HLB value can be calculated using the following method: HLB = 20 x (molar mass of the hydrophobic part) / (molar mass of the molecule).

[0047] "Chelating agents" are understood to mean, for example, ligands which form chemical complexes with metal ions, such as copper ions, iron ions, nickel ions, calcium ions and magnesium ions.

[0048] "Fatty acid" is understood to mean, for example, aliphatic monocarboxylic acids.

[0049] The proportions of the various components a), b), c), d) and e) and possibly f) and g) are stated in % by mass relative to the total mass of the thermoplastic at ambient temperature. DETAILED DESCRIPTION

[0050] The biodegradable thermoplastic may be water soluble.The biodegradable thermoplastic may be printable and / or printed.

[0051] The thermoplastic comprises a) 50% to 80%, preferably 52% to 75%, even more preferably 55% to 70%, or still more preferably 60% to 65% casein and / or caseinate.

[0052] Casein is a protein found in milk, which is insoluble in water. It is mainly obtained by precipitation by adding acid (acid casein) or rennet (rennet casein) to milk. Casein consists of a mixture of α-casein, β-casein and κ-casein, with a molar mass of 19000 g / mol to 25000 g / mol. Caseinate is understood to mean, for example, salts of casein, whose counterions are selected from calcium, potassium, ammonium, sodium and magnesium ions.

[0053] According to one embodiment of the thermoplastic, a) comprises at least one casein.

[0054] According to another embodiment of the thermoplastic, a) comprises at least one caseinate, for example sodium caseinate or a mixture of caseinates.

[0055] According to another embodiment of the thermoplastic, a) comprises a mixture of casein and at least one caseinate. In this case, the mass ratio of casein to caseinate may be 5 / 95 to 95 / 5, 20 / 80 to 80 / 20, or 40 / 60 to 60 / 40.

[0056] The thermoplastic contains b) 4 to 13%, preferably 4.5 to 12%, even more preferably 5 to 11%, or still more preferably 7 to 10.5% of water. Water as a plasticizer must be distinguished from the plasticizer c) that enters the thermoplastic composition according to the invention.

[0057] The latter in fact comprises c) 10% to 35%, preferably 12% to 32%, even more preferably 15% to 28%, or still more preferably 20% to 25% of at least one plasticizer c) different from b).

[0058] The plasticizer c) may be selected from polyols, glyceryl acetate, glyceryl propionate and mixtures thereof.

[0059] The following can be given as examples of polyols: glycerol, hexanetriol, glycols including ethylene glycol, and sugars and their derivatives.

[0060] The following can be given as examples of sugars: disaccharides such as maltose, lactose, and sucrose, and monosaccharides such as fructose.

[0061] Among sugar derivatives, the following may be cited as examples of hydrogenated derivatives thereof: sorbitol, maltitol, mannitol and xylitol, or even conversion products of these hydrogenated derivatives, such as sorbitan.

[0062] According to one embodiment of the thermoplastic, the plasticizer c) is selected from glycerol, sorbitol, mannitol, ethylene glycol and mixtures thereof. Preferably, the plasticizer c) is glycerol.

[0063] The plasticizer c) may contain residual water.

[0064] Plasticizers c) are used to reduce the viscosity of the product by increasing the mobility of the molecular chains.

[0065] Advantageously, the plasticizer c) is a hydrophilic plasticizer.

[0066] The thermoplastic comprises d) 0.1% to 8%, preferably 0.5% to 6%, even more preferably 1% to 4%, or still more preferably 1% to 3% of a hydrophobizing agent d).

[0067] The hydrophobic agent d) may be selected from:

[0068] - polycarboxylic acid esters;

[0069] - C3 to C33 carboxylic acids, preferably C4 to C28 fatty acids, even more preferably C6 to C28 unsaturated fatty acids;

[0070] - and mixtures thereof.

[0071] The polycarboxylic acid ester may be derived from at least one polycarboxylic acid and at least one alcohol, preferably a C1 to C18 alcohol.

[0072] Among the polycarboxylic acids that are preferred within the scope of the present invention, mention may be made of citric acid, hydroxycitric acid, tartaric acid, malic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid and fumaric acid.

[0073] Among the preferred alcohols according to the invention, mention may be made of C2 to C6 alcohols, such as ethanol, n-propanol, isopropanol, n-butanol and tert-butanol.

[0074] According to one embodiment of the thermoplastic, the hydrophobizing agent d) is selected from triethyl citrate, tributyl O-acetyl citrate, tributyl citrate and mixtures thereof.

[0075] According to one embodiment, the hydrophobic agent d) is a C3 to C33 carboxylic acid, preferably a C4 to C28 fatty acid, even more preferably a C6 to C28 unsaturated fatty acid.

[0076] Among the C4 to C28 fatty acids selected within the scope of the present invention, mention may be made of caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid and mixtures thereof.

[0077] Among the particularly attractive C6 to C28 unsaturated fatty acids, mention may be made of palmitoleic acid, oleic acid, linoleic acid and mixtures thereof.

[0078] The thermoplastic comprises e) 0.5% to 6%, preferably 1% to 5%, even more preferably 1.5% to 4.5%, or still more preferably 2% to 4% of at least one surfactant.

[0079] According to one embodiment of the thermoplastic, the surfactant e) is selected from zwitterionic surfactants having an HLB of 2 to 8.

[0080] Among the preferred surfactants, mention may be made of lecithin and / or its analogs, such as diacetylenic phosphonates.

[0081] According to one embodiment of the thermoplastic, the ratio of the amounts of e) to d) is greater than or equal to 1. For example, this ratio may be between 1.3 and 3; preferably between 1.5 and 2.5.

[0082] According to one embodiment of the thermoplastic, the material comprises from 1% to 5% of an additive chosen from chelating agents f). Among the chelating agents, mention may be made of diammonium citrate, EDTA, phosphates, citric acid, pyrophosphates and mixtures thereof.

[0083] According to one embodiment of the thermoplastic, the material further comprises an additive g) selected from colorants, protein coagulants and anti-caking agents, slip agents and mixtures thereof. Among the coagulants, citric acid and acetic acid may be mentioned. Among the anti-caking agents, colloidal silicon dioxide may be mentioned. Among the slip agents, polyethylene glycol and preferably fatty chain compounds with amide at the end of C12 to C28 may be cited. Among the release agents, polyvinyl alcohol may be mentioned. The biodegradable thermoplastic may contain 0.1% to 5% of g).

[0084] According to one embodiment of the biodegradable thermoplastic, the material comprises:

[0085] a) 50% to 80%, preferably 52% to 75%, more preferably 55% to 70%, or still more preferably 60% to 65% casein and / or caseinate;

[0086] b) 4 to 13%, preferably 4.5 to 12%, even more preferably 5 to 11%, or still more preferably 7 to 10.5% water;

[0087] c) 10% to 35%, preferably 12% to 32%, even more preferably 15% to 28%, or still more preferably 20% to 25% glycerol;

[0088] d) 0.1% to 8%, preferably 0.5% to 6%, more preferably 1% to 4%, or still more preferably 1% to 3% C6 to C28 unsaturated fatty acids;

[0089] e) 0.5% to 6%, preferably 1% to 5%, even more preferably 1.5% to 4.5%, or still more preferably 2% to 4% lecithin.

[0090] According to a specific embodiment, the biodegradable thermoplastic is made only of components that can be used in the agro-food industry, i.e., components included in the Food Codex. In this case, the biodegradable thermoplastic is edible, i.e., it can be eaten without harming the body. For example, when the biodegradable thermoplastic is made of:

[0091] a) casein and / or caseinate;

[0092] b) water;

[0093] c) glycerol;

[0094] d) oleic acid; and

[0095] e) lecithin,

[0096] Thermoplastics are edible.

[0097] Typically, the biodegradable thermoplastic is in the form of pellets or films.The invention also relates to pellets of a thermoplastic as described above.

[0098] The present invention also relates to one or more granules comprising:

[0099] a) 50% to 80%, preferably 52% to 75%, more preferably 55% to 70%, or still more preferably 60% to 65% casein and / or caseinate;

[0100] b) 4 to 13%, preferably 4.5 to 12%, even more preferably 5 to 11%, or still more preferably 7 to 10.5% water;

[0101] c) 10% to 35%, preferably 12% to 32%, more preferably 15% to 28%, or still more preferably 20% to 25% of at least one plasticizer different from b);

[0102] d) 0.1% to 8%, preferably 0.5% to 6%, more preferably 1% to 4%, or still more preferably 1% to 3% of a hydrophobic agent;

[0103] e) 0.5% to 6%, preferably 1% to 5%, even more preferably 1.5% to 4.5%, or still more preferably 2% to 4% of at least one surfactant.

[0104] According to one embodiment of the pellets, the pellets comprise:

[0105] a) 50% to 80%, preferably 52% to 75%, more preferably 55% to 70%, or still more preferably 60% to 65% casein and / or caseinate;

[0106] b) 4 to 13%, preferably 4.5 to 12%, even more preferably 5 to 11%, or still more preferably 7 to 10.5% water;

[0107] c) 10% to 35%, preferably 12% to 32%, even more preferably 15% to 28%, or still more preferably 20% to 25% glycerol;

[0108] d) 0.1% to 8%, preferably 0.5% to 6%, more preferably 1% to 4%, or still more preferably 1% to 3% of C6 to C28 unsaturated fatty acids;

[0109] e) 0.5% to 6%, preferably 1% to 5%, even more preferably 1.5% to 4.5%, or still more preferably 2% to 4% lecithin.

[0110] Typically, the pellets are water soluble.The pellets may be edible.

[0111] The invention also relates to an article which can be obtained after transformation of a thermoplastic as described above by extrusion casting, extrusion blow molding, film blowing, solvent casting, calendering, injection molding, thermoforming or stretching.

[0112] Mention may in particular be made of films obtainable from the thermoplastics described above.

[0113] The invention also relates to a film obtained from a thermoplastic as described above. The film can be obtained, for example, by film blowing of pellets of a thermoplastic as described above. The film is a biodegradable thermoplastic film. The film can be printed. Typically, the film has a thickness of 15 μm to 100 μm, preferably 30 μm to 80 μm, more preferably 40 μm to 70 μm. The film can be directly printed by conventional printing methods used in plastic processing, such as flexographic printing, before winding, or in a second step of unwinding, cutting and rewinding.

[0114] The present invention also relates to a film comprising:

[0115] a) 50% to 80%, preferably 52% to 75%, more preferably 55% to 70%, or still more preferably 60% to 65% casein and / or caseinate;

[0116] b) 4 to 13%, preferably 4.5 to 12%, even more preferably 5 to 11%, or still more preferably 7 to 10.5% water;

[0117] c) 10% to 35%, preferably 12% to 32%, more preferably 15% to 28%, or still more preferably 20% to 25% of at least one plasticizer different from b);

[0118] d) 0.1% to 8%, preferably 0.5% to 6%, more preferably 1% to 4%, or still more preferably 1% to 3% of a hydrophobic agent;

[0119] e) 0.5% to 6%, preferably 1% to 5%, even more preferably 1.5% to 4.5%, or still more preferably 2% to 4% of at least one surfactant.

[0120] According to one embodiment of the membrane, the membrane comprises:

[0121] a) 50% to 80%, preferably 52% to 75%, more preferably 55% to 70%, or still more preferably 60% to 65% casein and / or caseinate;

[0122] b) 4 to 13%, preferably 4.5 to 12%, even more preferably 5 to 11%, or still more preferably 7 to 10.5% water;

[0123] c) 10% to 35%, preferably 12% to 32%, even more preferably 15% to 28%, or still more preferably 20% to 25% glycerol;

[0124] d) 0.1% to 8%, preferably 0.5% to 6%, more preferably 1% to 4%, or still more preferably 1% to 3% of C6 to C28 unsaturated fatty acids;

[0125] e) 0.5% to 6%, preferably 1% to 5%, even more preferably 1.5% to 4.5%, or still more preferably 2% to 4% lecithin.

[0126] Typically, the film is water soluble. The film may be edible. The film may be heat shrinkable.

[0127] The invention also relates to the use of thermoplastics, such as films as described above, for packaging various products (e.g., pharmaceuticals, foods, chemicals, cosmetics, etc.), in particular hygroscopic products, even more particularly detergents. The products may be in solid or liquid form.

[0128] The invention also relates to a product packaged by a thermoplastic as described above, for example by a film as described above. The packaged product may be selected from the group consisting of pharmaceuticals, foods, chemicals and cosmetics.

[0129] According to one embodiment, the packaged product is a food product, such as meat, fish, vegetables, fruit, desserts, pies and cakes, food additives, ingredients, dry preparations and food powders. According to a specific embodiment, the thermoplastic used for packaging food is an edible film. According to a specific embodiment, the packaged product is a detergent bar.

[0130] According to one embodiment, the packaged product is a liquid product, such as a liquid shampoo or a liquid laundry product.

[0131] The invention also relates to a detergent packaged by means of a thermoplastic as described above, for example by means of a film as described above.

[0132] The detergent may be in liquid form or in powder form, it may be compacted or non-compacted. For example, it may involve a detergent block. Among detergent blocks, mention may be made of product blocks for dishwashers and laundry blocks.

[0133] According to another of its aspects, the invention relates to a process for preparing a thermoplastic as described above.

[0134] The method preferably comprises the following steps:

[0135] E1. Using an extruder, preferably a twin-screw extruder;

[0136] E2. Compounds a) to e) and possibly f) are added to the extruder;

[0137] E3. Retrieving at least one extruded thermoplastic rod;

[0138] E4. Optionally drying the rod;

[0139] E5. Optionally break the rods into pellets.

[0140] Advantageously, step E1 comprises running the extruder using the following parameters: a rotation speed ranging from 100 to 150 RPM, a temperature ranging from 70°C to 120°C.

[0141] Step E2 preferably comprises adding simultaneously or sequentially, preferably sequentially:

[0142] In the first step,

[0143] at least a portion of the compounds a) to e) and possibly f) in solid form, advantageously in powder form, and

[0144] In the second step,

[0145] At least a portion of the compounds a) to e) and possibly f) is advantageously in liquid form.

[0146] In a preferred embodiment, the compounds in solid form, advantageously in powder form, are compounds a) and e); and the compounds in liquid form are compounds b), c) and d).

[0147] According to another aspect thereof, the present invention relates to a method for packaging a product using a heat shrink film as described above. The heat shrinking can be accomplished by heat shrinking techniques known to those skilled in the art. For example, the product to be packaged is wrapped in a sheet of film which is then heat sealed. The product to be packaged may be a compacted powder block, such as a detergent block.

[0148] The film is heat shrunk by passing an air stream having a temperature of 80 to 200° C., preferably 100 to 170° C., even more preferably 130 to 160° C., for a period of 0.05 to 60 seconds, preferably 1 to 30 seconds, still more preferably 2 to 10 seconds. The film then assumes the shape of the packaged product.

[0149] According to one embodiment, before heat shrinking, the membrane is wetted with water or equivalent liquid by a sprayer and / or a humidifier and / or an evaporator on at least one of the two surfaces and / or edges of the block for a period of about 0.01 seconds to 60 seconds.

[0150] Heat shrinking can also be performed by placing the film in an oven, and the relative humidity level in the oven can be controlled. The relative humidity level can be, for example, 10% to 80%, 10% to 40%, or 20% to 40%, or greater than or equal to 30%.

[0151] According to one embodiment, the method comprises the following steps:

[0152] - Wrap the product to be packaged in a film,

[0153] - heat sealing film,

[0154] - optionally wetting the membrane, and

[0155] - Heat shrinking the film at a temperature between 80°C and 200°C.

[0156] Example

[0157] Thermoplastic Granules and membrane preparation

[0158] The extruder used to make the following examples is The BC 21 co-rotating twin-screw extruder of the brand has a diameter of 25 mm, a center line distance of 21 mm, and a length of 900 mm. The extruder includes at least four zones:

[0159] - a first area for adding;

[0160] - a second area for adding;

[0161] - a third zone for degassing; and

[0162] - A fourth zone for die extrusion.

[0163] The twin screws were rotated at 125 RPM and the temperature in each zone was between 70°C and 120°C.

[0164] The first zone of the extruder is the one for adding the powders: caseinate and lecithin. In the second zone the liquid (plasticizer) is added. The extruder also comprises a zone for degassing to free air and a final zone consisting of a cylindrical rod die of 4 mm diameter.

[0165] The following is a brief description of the screw:

[0166] -750mm positive step screw

[0167] -50mm mixing screw

[0168] -100mm reverse step screw

[0169] At the exit of the extruder, the rods are dried and put into a pelletizer to obtain pellets with a diameter of 2 to 3 mm. The pellets are then converted into films by film blowing. The film blowing machine used is It has a diameter of 30 mm and is equipped with an annular die of 80 mm diameter. The prepared film is about 30 cm wide and 50 μm thick. The resulting film is 1200 m long and is wound to form a roll. The roll of this film is then used to package a detergent block. A block of 37 mm × 27 mm × 15 mm is wrapped with a sheet of 107 mm × 70 mm film. The film is then heat-sealed at its ends longitudinally and transversely. Different film formulations for packaging blocks were tested.

[0170] Expand the test

[0171] The tools used in this test are Figure 6 It comprises a roll (1) of a membrane (2) to be tested (partially shown in Figure 6 The film (2) passes through a counter roller (3) and is then wound on a drive roller (4) of 10 cm diameter and 30 cm length equipped with an ASA-RT brand 50N force sensor (5). The force sensor (5) is used to measure the tension near the film winder during the unwinding process. The drive roller (4) rotates at a speed of 5 RPM to unwind the roll (1) of the film (2).

[0172] The thickness of the film (2) was 50 μm and the width from edge to edge was 30 cm.

[0173] Force sensors (5) are used to quantify the concept of "stickiness", which is an obstacle to industrial use.

[0174] If the force sensor displays a force exceeding 2N (0.2kg force), the roll is described as "sticky".

[0175] Packaging Testing

[0176] The packaged detergent blocks were stored at 30°C and 30% relative humidity for five days. Afterwards, each packaged block was grasped with a latex glove, shaken three times by holding one end with a gloved dry finger, then placed in the gloved dry palm, and then the gloved dry finger was closed over the block three times to break it up. If the film opened or broke during this test, it was described as "brittle".

[0177] Printed film

[0178] Figure 5A and Figure 5B The film shown for the packaging blocks (according to Example 5) was printed directly by flexographic printing before being wound up.

[0179] The results are shown in Table 1.

[0180]

[0181] Table 1: Formulations tested and results of unpacking and packaging testing.

[0182] Examples 1 to 3 are comparative examples; these films cannot be used industrially because they do not pass the unfolding test and / or the packaging test.

[0183] Figure 1A and Figure 1B is a photograph of a roll of film according to Comparative Example 1 that could not be unrolled.

[0184] Examples 4 and 5 are examples according to the present invention, and these films passed the packaging and unwrapping tests; therefore, they can be used industrially and for packaging detergent bars.

[0185] Figure 2A , Figure 2B and Figure 2C is a photograph of a roll of film according to Comparative Example 4 that can be unrolled.

[0186] These figures show the absence of tack effects as evidenced by the deployment forces of < 200 g in the deployment test.

[0187] Figure 3A and Figure 3B is a photograph of a detergent block packaged in a film according to Example 1 after five days of packaging testing.

[0188] The disintegration of the packaging film is clearly shown in these figures.

[0189] Figure 4 is a photograph of a detergent block packaged in a film according to Comparative Example 4 after five days of packaging testing.

[0190] The packaging film is intact. No cracks.

[0191] Photo 5A and Photo 5B are photographs of detergent bars packaged in the printed film according to Example 5 after five days of packaging testing.

[0192] The packaging film was also intact and free of cracks. The printing present on the film was not deteriorated.

[0193] Heat shrink

[0194] A 5 cm x 5 cm piece of film according to Example 5 was heat shrunk in an oven at 100°C for 30 seconds, where the relative humidity level could be controlled. The heat shrinkage levels in the longitudinal and transverse directions were then measured. The results are shown in Table 2.

[0195] These results show that the film of Example 5 according to the present invention is heat shrinkable.

[0196]

[0197] Table 2: Shrinkage rate for each

[0198] Injection Molding

[0199] The biodegradable thermoplastic pellets according to Example 4 above were used to prepare injection-molded parts. An injection-molded press of the Sumitomo brand, Demag Systec 35-200 model, was used.

[0200] The temperature of the barrel and nozzle was adjusted to 95°C to 115°C.

[0201] The mold temperature was 15°C and the injection speed was 20 mm / s.

[0202] Photographs 7A and 7B are photographs of parts obtained by injection moulding. These results show that articles can be made by injection moulding from thermoplastic pellets according to the invention.

Claims

1. A biodegradable thermoplastic, characterized in that: In mass %, it contains: a) 50% to 80% casein and / or caseinate; b) 4% to 13% water; c) 10% to 35% of at least one plasticizer different from b); d) 0.1% to 8% of a hydrophobic agent; e) 0.5% to 6% of at least one surfactant; The sum of the mass % of all components is 100%; wherein the plasticizer c) is selected from polyols, acetin, propionin and mixtures thereof; The hydrophobic agent d) is selected from: - polycarboxylic acid esters; - C3 to C33 carboxylic acids; - and mixtures thereof; and The surfactant e) is selected from zwitterionic surfactants with an HLB of 2 to 8.

2. The thermoplastic plastic according to claim 1, characterized in that In mass %, it contains: a) 52% to 75% casein and / or caseinate; b) 4.5% to 12% water; c) 12% to 32% of at least one plasticizer different from b); d) 0.5% to 6% of a hydrophobic agent; e) 1% to 5% of at least one surfactant.

3. The thermoplastic plastic according to claim 1, characterized in that In mass %, it contains: a) 55% to 70% casein and / or caseinate; b) 5% to 11% water; c) 15% to 28% of at least one plasticizer different from b); d) 1% to 4% of a hydrophobic agent; e) 1.5% to 4.5% of at least one surfactant.

4. The thermoplastic plastic according to any one of claims 1 to 3, characterized in that c) is glycerol.

5. The thermoplastic plastic according to any one of claims 1 to 3, characterized in that The hydrophobic agent d) is selected from: - polycarboxylic acid esters; - C4 to C28 fatty acids; - and mixtures thereof.

6. The thermoplastic according to any one of claims 1 to 3, characterized in that The hydrophobic agent d) is selected from: - polycarboxylic acid esters; - C4 to C28 unsaturated fatty acids; - and mixtures thereof.

7. The thermoplastic plastic according to any one of claims 1 to 3, characterized in that The hydrophobic agent d) is selected from palmitoleic acid, oleic acid, linoleic acid and mixtures thereof.

8. The thermoplastic according to any one of claims 1 to 3, characterized in that The ratio of the amounts of e) to d) is greater than or equal to 1.

9. The thermoplastic plastic according to any one of claims 1 to 3, characterized in that It comprises from 1% to 5% of an additive f) selected from chelating agents.

10. The thermoplastic plastic according to any one of claims 1 to 3, characterized in that It comprises an additive g) selected from a colorant; a protein aggregating agent; an anti-caking agent; a slip agent; and a mixture thereof, wherein the slip agent is selected from polyethylene glycol and a fatty chain compound having an amide terminal.

11. The thermoplastic according to claim 10, characterized in that The fatty chain compound having an amide at the terminal is a fatty chain compound having an amide at a C12 to C28 terminal.

12. The thermoplastic plastic according to any one of claims 1 to 3, characterized in that It is water soluble.

13. The thermoplastic according to any one of claims 1 to 3, characterized in that It is edible.

14. Granules of thermoplastic plastic, the thermoplastic plastic being according to any one of claims 1 to 13.

15. An article obtainable after transformation of the thermoplastic according to any one of claims 1 to 13 or the pellets according to claim 14 by solvent casting, calendaring, thermoforming or stretching.

16. The article according to claim 15, characterized in that The thermoforming is extrusion casting, extrusion blow molding, film blow molding or injection molding.

17. The article according to claim 15, characterized in that It includes membranes.

18. The article according to claim 17, characterized in that The film is printed.

19. The product according to claim 17 or 18, characterized in that The film is heat shrinkable.

20. A product characterized by It is packaged with a film according to any one of claims 17 to 19.

21. The product according to claim 20, characterized in that It includes detergent tablets.

22. The product according to claim 20, characterized in that It includes food.

23. The product according to claim 20, characterized in that It includes liquid shampoo.

24. A method for preparing a thermoplastic according to any one of claims 1 to 13, characterized in that The method comprises the following steps: E1 uses an extruder; E2 adding compounds a) to e) and possibly f) to the extruder; E3 retrieves at least one extruded rod of thermoplastic; E4 optionally drying the rod; E5 Optionally break the rods into pellets.

25. The method for preparing a thermoplastic according to claim 24, characterized in that A twin-screw extruder is used in step E1.

26. The method for preparing a thermoplastic according to claim 24, characterized in that Step E2 comprises adding simultaneously or sequentially: In the first step, at least a portion of compounds a) to e) and possibly f) in solid form, and In the second step, At least a portion of compounds a) to e) and possibly f) is in liquid form.

27. The method for preparing a thermoplastic according to claim 26, characterized in that In the first step at least a portion of the compounds a) to e) and possibly f) are in powder form.

28. The method for preparing a thermoplastic according to claim 26, characterized in that The addition in step E2 is sequential addition.

29. A method for packaging a product using the film according to claim 19, characterized in that The method comprises the following steps: - Wrap the product to be packaged in a sheet of film, - heat sealing film, - optionally wetting the membrane, and - Heat shrinking the film at a temperature between 80°C and 200°C.

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