BRPI1104823A2 - Biodegradable and recyclable material preparation process for the manufacture of thermoformed objects - Google Patents

Abstract

The process of preparing biodegradable and recyclable material for the manufacture of thermoformed objects is that the dry or wet biodegradable material is added to a gel formed by the mixture of water, starch or cellulose followed by heating to a temperature of up to 100 ° C. preferably at a variable temperature according to the botanical starch source for a minimum of 15 minutes and additives. The mixture is then homogenized by an industrial stirrer and the premix is subjected to an extruder or injector. The foam exited from the extruder or injector is then compression molded into the desired shape, such as pots, cups, cutlery, plates, trays, planting tubes and others, depending on the mold used. allowing the starch or cellulose to soak in excess of water for a minimum of 15 minutes prior to preparing the gel or formulation makes the starch or cellulose granules capable of absorbing water and retaining it. , even when subjected to high processing temperatures, thus achieving fully biodegradable foam materials with excellent mechanical properties, low solubility, low density, stable and light in color.

Description

PREPARATION PROCESS FOR BIODEGRADABLE AND RECYCLABLE MATERIAL FOR MANUFACTURE OF THERMOFORMED OBJECTS

This invention, pertaining to the sector of compositions of macromolecular starch compounds and lignocellulosic materials (cellulose, hemicellulose, lignin, their extracts or mixtures thereof), relates to the manufacture of biodegradable and recyclable foam-type packaging and containers, and in particular to the use of cassava and sugar cane in such products.

BACKGROUND AND TECHNICAL STATUS

Large amounts of plastic waste accumulate day after day in landfills, which hinders the circulation of liquids and gases in the soil, and even slows down the stabilization of organic matter. Industrial solid waste generation in Brazil is around 140,000 tons / day, with only 50% receiving adequate treatment. As for municipal solid waste, the generation is 100,000 tons / day with 60 to 70% destined for dumps. About 1 million plastic bags and Styrofoam packaging are dumped per minute on the planet. In São Paulo it is estimated that 18% of the waste is composed of this material and about 90% of all plastic produced to date, worldwide, has not yet decomposed. Packaging made of expanded polystyrene (Styrofoam) can take up to 150 years to deteriorate In Ireland, since 2002 a tax has been levied on the use of each oil-based plastic bag and in Lajeado (RS), the city distributes fabric bags for the shopping. Since March 2007, the City of San Francisco has been enacting a law that prohibits the use of non-biodegradable plastic bags by supermarket chains and pharmacies; A law in Rio de Janeiro, passed in July 2009, obliges the state's commercial establishments to exchange plastic bags for bags made of recyclable material by 2012, punishing violators with fines of up to R $ 10,000 per infraction. In addition to Rio de Janeiro, governments in four Brazilian states have passed laws against the use of plastic bags: Espírito Santo, Maranhão, Pernambuco and Paraná, and in Santa Bárbara DOeste, São Paulo, there is a bill to create preferential cashiers in supermarkets to who chooses not to use a plastic bag.

Among the raw materials from renewable sources and generators of biodegradable products for the manufacture of foamed products, starch and cellulose, especially cassava starch and sugarcane bagasse, stand out for several reasons: ) availability - cassava is grown in all Brazilian states, being among the first nine agricultural products in the country in terms of cultivated area and bagasse is the largest residue of Brazilian agro-industry, with an estimated generation of 5 to 12 million. (b) packaging obtained from cassava starch and bagasse has advantages over non-biodegradable packaging, such as Styrofoam, especially (1) the process of obtaining involves use of non-toxic substances and without the use of chlorofluorocarbons, harmful to the ozone layer; (2) it takes 1 to 50 days to degrade without leaving residues, depending on the biodegrading activity of the litter or soil, and (3) polystyrene replacement reduces oil consumption.

However, low water resistance, variations in mechanical properties under moisture, low impact strength and small thickness of thermoformed products limit the use of starch and cellulose packaging.

Another limiting factor of these packages is the difficulty in processing starch by extrusion, as thermoplastic starch (TPS) is produced by plasticizing starch in the presence of a plasticizer at high temperatures and shear due to extrusion. The chemical nature of starch and the amount of plasticizer, as well as the temperature required to plasticize it in the extruder, have an important influence on the mechanical and barrier properties of the formed TPS. Brazilian patent application PI 0502338-6, "Formulation for the production of water-resistant starch foams and cooling, freezing and thawing cycles" discloses a foam made of starch in which a suitable formulation, composed basically of water and starch, It is expanded at a high temperature for the production of packaging foams. Such packages are resistant to various temperature ranges, especially low temperatures, and to cooling, freezing and thawing cycles, showing that the viscosity of the mixture is a prime factor for the low temperature resistance of the obtained foams. It also reveals that mixtures with high amounts of water in their composition, and consequently high flowability, once expanded do not form foam structures strong enough to withstand cooling, freezing and thawing cycles, and that the use of thickeners, gelatinized starch in water in concentrations higher than 3% or the use of organic or inorganic fillers increases the viscosity of the dough, improving the freezing and thawing resistance of the obtained foams and also that the addition of organic and inorganic plasticizers and fillers to the formulation. may increase the adhesion of the coating to the foam surface.

For the production of starch foams, the mixture (starch, water and additives) must have a moisture content between 25 and 99% relative to the starch weight, depending on the equipment and process used, additive (plasticizers, thickeners) diluted 0, 5 to 50% in water. The mixture may be added with organic, inorganic fillers, pigments and dyes at concentrations between 0.1 and 10%. The mixture may be processed by thermoexpansion, extrusion, injection and thermoforming.

It should be noted that this patent application focuses on establishing an ideal concentration of water applied over all starch, aiming at the use of the package at low temperatures not previously achieved, and furthermore, that such formulation could not be heated. at high temperatures. Brazilian patent application PI0804862-2 "Product consisting of additives and active agents for biodegradable and / or non-compostable foams and packaging coatings and preparation method" discloses that active agents and additives are used in the invention depending on the characteristic to be given to the biodegradable packaging foam, improving the increase in foam compression strength after waterproofing with the product, increased foam resistance to water and substrate resistance to water, oil and fat and other active and intelligent character, such as the ability to absorb oxygen, prevent fungal proliferation, control ethylene levels inside the package, avoid weight loss and nutritional value of the food, absorb unpleasant odors and tastes, preserve food color, absorb energy incident on packaging, disable photoexcited chromophores, incorporate preservatives and quality monitor indicators and have invoice of the packed product.

This patent application discloses the addition of actives and additives aimed at increasing the adhesion strength of a waterproofing film to the biodegradable substrate, increasing the compressive strength of the foam after sealing with the product and increasing the foam, water, oil and fat resistance. , in addition to other intelligent features.

It should be noted that in the patent application BIODEGRADABLE AND RECYCLABLE MATERIAL PREPARATION PROCESS FOR MANUFACTURE OF THERMOFORMED OBJECTS ”there is no need to include additives to improve mechanical or barrier properties. Brazilian patent application PI 0603932-4 “Temperature-resistant starch foams corresponding to conventional domestic oven, food industry oven and domestic microwave oven” reveals that the limited amount of water in the mixture is a prime factor for foam resistance to high temperatures, preventing deformation, and the foam obtained by the mixture of water and starch processed hot. The foam is made of starch, in which a suitable formulation composed basically of water and starch is expanded at high temperature for the production of packaged foams. Such packages have good mechanical resistance and good thermal resistance, resisting several temperature ranges, mainly high, and can be subjected to conventional domestic oven, industrial oven and domestic microwave oven. According to the invention, the limited amount of water in the mixture is a prime factor for the high temperature resistance of the obtained foams, preventing them from deforming. The use of thickeners, organic or inorganic fillers reduces the amount of free water in the mixture and thereby improves their resistance to high temperatures. For the production of starch foams, the mixture (starch and water) must have a minimum humidity of 10% and a maximum of 70% relative to solids, depending on the type of starch, equipment and process used.

It is to be noted that in the present invention "PROCESS FOR PREPARATION OF BIODEGRADABLE AND RECYCLABLE MATERIAL FOR MANUFACTURE OF THERMOFORMED OBJECTS", up to 1: 9 mass ratio between starch and water is used. Brazilian patent application PI 1002499-9 “Process for obtaining biodegradable or compostable active foams from renewable sources” reveals as novelty and inventive activity the incorporation of active and or intelligent agents to the granules of renewable source raw material by means of a pre-gelatinization of the material, so that the active and / or intelligent agents are surrounded by the starch granules, not allowing their passage to the cooking water, avoiding the loss of its chemical structure and biological activity.

In order to improve starch and shear processability, patents such as US 7,384,993 and US 5,569,692 disclose the addition of water to the starch and plasticizer mixture during processing in the extruder, which is deemed necessary for starch to be be processed in an extruder at a temperature of 120 to 170 ° C, since the connections between water and starch do not generate a vapor pressure as required for high pressure processing; or US 5,362,777 which discloses the addition of additives such as dimethyl sulfoxide for example to reduce the melting point of starch and thus be able to process it in extruder. The use of the extrusion process to obtain products has many advantages, such as high productivity, low cost, products with varied shapes, high quality and, mainly, not producing effluents. The control of the extrusion process allows to obtain products with varied characteristics, improving the efficiency and economy of the operation. Although extrusion is a simple technological process, its control is quite complicated due to the large number of variables involved in the process and its complexity, and the extrusion conditions such as temperature, screw rotation, mass moisture content, among others. others are essential to ensure the good quality of the formed product. Among the product characteristics affected by the extrusion process variables, we can highlight: (1) the final moisture content, which affects shelf life and dough stability; (2) expansion, which affects volume, size and shape; (3) solubility, which is influenced by adhesion and cohesion; (4) absorption of water, milk and fat that affects the integrity of the final product; (5) visual appearance, which affects color; (6) density, which affects the size and weight of the end product, and (7) mechanical properties, which mainly affect the compressive strength and flexibility of the end product.

During heating of starch dispersions - in the presence of excess water - there is swelling and disruption of their granules, with destruction of the molecular order and irreversible changes in their properties. The temperature at which this type of transformation occurs is called gelatinization temperature (process of transformation of granular starch into viscoelastic paste - gel). Starch gelatinization temperature varies by source, for example potato starch gelatinization temperature 56 to 66 ° C, cassava starch temperature 62 to 66 ° C, rice starch 61 to 66 ° C 77 ° C, and the gelatinization temperature of the cornstarch is 56 to 72 ° C.

The needs of the food processing or even packaging industries for the use of starches with special properties have led to the production of modified starches. Starch is modified to enhance or inhibit its original characteristics and suit it for specific applications such as decreasing water solubility, improving mechanical properties, thickening, improving retention, increasing stability, improving luster, gelling, dispersing or opacity. . In unmodified form, starches have limited use in the processing industry. Native starches are perfectly adapted to freshly made products, prepared without much concern for conservation, but barely stand the technological demands of certain industrial processes, which include mainly exposure to wide temperature ranges, pH and shear, and have many characteristics that make them impractical to work with, such as the need for heating or chemical treatment of dispersed granules which can be an obstacle for some applications. Modifications made to starch can be chemical, physical or enzymatic, however, many of the modifications generate high cost, low productivity, high reaction time and residue formation.

High temperatures during starch or cellulose processing may cause material darkening (caramelization), starch or cellulose degradation, increased solubility of the formed material and decreased moisture - factors that may compromise the efficiency of the final product. Since water has plasticizing power, the resistance of the material formed to compression is directly related to its moisture content. Unlike most plastic materials, starch and bagasse have hydrophilic characteristics, that is, they absorb water, and their mechanical properties are altered by this characteristic, therefore the increase of temperature and consequent decrease of water content (moisture) of the formed material. may cause brittle and brittle materials to be obtained (low mechanical strength).

Other consequences of the influence of temperature in decreasing the moisture content of the formed material are the increase of mass instability and obtaining denser material. This is because water, together with temperature, is responsible for the generation of steam that causes mass expansion and foam formation (rigid structure) at the extruder outlet. Material produced with larger amounts of water expands more easily during the extrusion process, generating less dense and more flexible foams. Already the material formed with smaller amounts of water expands less, generating denser and less flexible foams. Regarding mass instability, we can say that with the loss of water during the extrusion process, more mass is required for the formation of an entire foam, because water is responsible for mass expansion and foam formation. Therefore, to supply the lack of water during the thermoforming process, after extrusion, more and more mass is required for the formation of an entire piece (cups, cutlery, plates, trays, tubes, among others). It is an object of this invention to obtain a biodegradable and recyclable foamed product that can be processed and thermoformed into disposable or non-disposable products such as cups, cutlery, plates, trays, planting tubes and others with high mechanical resistance to cooling, freezing and drying cycles. defrosting, durability and high resistance to moisture and which remain with the product to last as long as the expected consumption time; obtain a biodegradable and recyclable material capable of withstanding higher temperatures in the extruder without burning or caramelizing; obtain an extruder mass that does not need to be immediately pressed into the desired shape (pots, trays, etc.); obtain decreased foam solubility in water, oil or fat; enable mixing of starch or cellulose with compounds that can only be processed at high temperatures; make it possible to work the extruder with various rotations in the thread and not only high rotations to avoid starch burning and to produce less dense foams.

BRIEF DESCRIPTION OF THE INVENTION

In the present invention, the starch or cellulose is soaked in excess water at a temperature of up to 100 ° C, preferably ambient, for a minimum of 15 minutes before preparing the gel or formulation, which causes that starch or cellulose granules are capable of absorbing and retaining water even when subjected to high processing temperatures, thus achieving fully biodegradable and recyclable foamed materials with excellent mechanical properties, low solubility, low density, stable and light in color, meeting the proposed objectives. The novelty and inventive activity of the present invention is to improve the mechanical and barrier properties and the visual appearance of the foams by soaking starch or cellulose pulp for at least 15 minutes in excess of water, making them foamy. more mechanically resistant, less dense, increases the ability to withstand high temperatures without burning or caramelizing and less water-soluble than those produced without such treatment.

DETAILED DESCRIPTION OF THE INVENTION The "PREPARATION PROCESS FOR PREPARATION OF BIODEGRADABLE AND RECYCLABLE MATERIAL FOR MANUFACTURE OF THERMOFORMED OBJECTS" consists initially of cellulose, mixed or not with starch, being added to the gel formed by mixing water, starch or cellulose followed by heating. and optionally compatible plasticizers and additives may be added. Thereafter, the mixture is homogenized, preferably by an industrial agitator, which premix is subjected to an extruder, preferably single screw equipped with three heating zones or double screw, or an injector. The foam exited from the extruder is then compression molded into the desired shape, such as pots, cups, cutlery, plates, trays, planting tubes and others, depending on the mold used. Foam from the extruder, formulated with water-immersed starch or cellulose, is wetter even when subjected to high temperatures, having a longer life than the foam produced with dry starch, making it possible to reuse the still-wet foam for production. of new parts.

When the foam is low in moisture, formulated with untreated starch, it tends to be brittle and poorly resistant. This tendency, known as the phenomenon of starch aging or retrogradation, produces a form of beta starch, as in hardened old bread, which decreases the compressive strength of foams over time. This already brittle foam cannot be reused.

Raw Materials Used (Percentages in m / m) Starch: Cassava starch up to 75%, preferably 30 to 70%, with particle size in the range 0.5 pm to 110 pm, preferably 4.0 to 35.0 pm .

Optionally, other starches from other botanical forms may be used, such as maize (3.0 to 23.0 pm); biri (25.0 to 45.0 pm); arrowroot (9.0 to 42.0 pm); sweet potato (2.0 to 42.0 pm) and ginger (15.0 to 20.0 pm), or mixtures thereof, all up to 75%, preferably 30 to 70%. CELLULOSE: sugarcane bagasse up to 75%, preferably from 5 to 30%, with fiber size from 3x10‘4 cm to 1 cm. Other cellulosic fibers of vegetable origin may be used, such as wood (pine, eucalyptus, fir), cotton, jute hemp, ramie, flax, mallow, coconut, banana, straw, rice husk, flax, cashew husk, Brazil nuts, acai, palm, abaca, curauá and others, or their mixtures, whether or not treated. Increasing the amount of starch or cellulose in the formulation leads to denser and more mechanically resistant foams. WATER, from 2% to 40% for gel formation, not considering an excess for processing, which should range between 2% and 90%, preferably between 30 and 84% by weight, for all ingredients added to the mass.

For wetting of the starting product (starch or cellulose or mixtures thereof), the starting ratio of water should be 1 to 9 by weight of the product, ie 1: 1 to 1: 9. ADDITIVES: Optionally can be added to improve processing or dough properties: • PLASTIFICANTS, from 0.5% to 20%, preferably from 1 to 3%, used to improve flexibility and processability, can be: water, alcohols, aldehydes, ketones, organic acids, amines, esters, amides, imides and polyols, such as ethylene glycol, propylene glycol, glycerin, propane-1,3-diol, butane-1,2-diol, butane-1,3- diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,5-diol, hexane-1,6-diol, hexane-1,2,6-triol, hexane-1,3, 5-triol, xylitol, neopentylglycol, polyvinyl alcohol, polyethylene glycol (PEG), polyglycerol, sorbitol, mannitol, sorbitol ester, sorbitol acetate, sorbitol diacetate, sorbitol monoethoxylate, sorbitol dihexate sorbitol dihexylate, sorbitol - sorbitol, trihydroxymethylaminomethane, glucose / PEG, trimethylolpropane monoethoxylate, mannitol monoacetate, mannitol monoethoxylate, butyl glycoside, monoe glucose toxylate, alpha-methyl glycoside, carboxymethyl sorbitol sodium salt, adipates, sebacates, linear phthalates, long-chain phthalates, n-octyl and n-decyl phthalates, butyloctylphthalate, epoxy, phosphates, chlorinated paraffins, butylbenzylphthalate, tricresi polyesters, phthalic acid and glycerine esters, trimethylates, thermoplastic polyesters, azelate, glutarate, succinate, polyvinyl acetate, polyvinyl alcohol, DMSO, mono- and diglycerides, coconut oil, or mixtures thereof. • COLORS OR PIGMENTS or their mixtures, from 0 to 10%, added to improve appearance and differentiate foams according to color, including according to the product to be packaged. Natural and synthetic organic and inorganic such as black may be used. smoke, titanium dioxide, chlorophylls, carotenoids, flavonoids, betalains, tannins, quinones and xanthones, tartrazine, twilight yellow, red 40, ponceau red, bright blue, anthocyanins, lapachol, erythrosine, flower extracts (quaresmeira, nail cow, azalea, among others), vegetable extract (bell pepper, cabbage, beet, among others), fruit extract (blackberry, jabuticaba, jambolão, grape, among others), annatto, beta-carotene, among others. • Cross-linking agents, aimed at changing the permeability to water vapor and gases: formic aldehyde, glutaric aldehyde, calcium benzoate, glutaraldehyde, borax, among others. • LUBRICANTS, intended to aid processing: silicones and fluorides, paraffin waxes, metal stearates, fatty acid esters, fatty acid amides, fatty acids, alcohols, among others. • Preservatives, organic and inorganic, natural or synthetic, aim to inhibit the growth of microorganisms (antimicrobial) and preservation free of spoilage caused by bacteria, fungi and yeast such as parabens, acids (benzoic acid, sorbic acid, among others), dioxide of sulfur and derivatives, nitrates, nitrites, phenoxyethanol, isothiazolinones, dimethyldimethylidantoin, iodopropynylbutyl carbamate, benzoic acid and its salts, esters of p-hydroxybenzoic acid, sulphates, sodium chloride, bacteriocins, sorbic acid, cinnamon, oregano and their derivatives . • Natural and synthetic organic and inorganic LOADS are used to increase mechanical, thermal and barrier resistance: kaolin, mullite, talc, calcite, bentonite, mica, illite, alumina, dolomite, smectite, montmorillonite, chromite, cyiamite, feldspar , graphite, pyrophyllite, gypsum, zirconite, minerals, calcium carbonate, calcium sulfate, iron oxide, barium sulfate, organic phosphorus compounds, polyphenols, hydroquinones, diarylamines, thioethers, nucleating agents (metal aromatic carboxylates, sorbitol, organic phosphates, talc, poly (vinyl cyclohexane), poly (3-methylbut-1-eno), silanols, release agents, metal salts, ground rocks, bauxite, granite, limestone, sandstone, clay, alumina, silica, microspheres glass, hollow glass spheres, porous ceramic spheres, insoluble salts, magnesium carbonate, calcium hydroxide, rare earths (found in the form of monazite, bastnasite, xenothymia minerals and loparite, and lateritic clays adsorbing ions), calcium aluminate, titanium dioxide, ceramics, light expanded clay, zirconium compounds, zeolites, metal particles, ores, glass fibers, graphite, silica, ceramics and metal, cotton, wood fibers, sisal, hemp, bagasse, recycled paper fibers, polymer fibers, invert sugar and sucrose, among others. • Natural and synthetic organic and inorganic thickeners and stabilizers used to increase viscosity and maintain physical characteristics: polysaccharides, pectins, gelatin, plant exudates, gums, chemically modified starches, cross-linked starches, cellulose derivatives, phosphates, salts and buffering agents, alginate, carboxymethylcellulose, agar, sorbitol, sorbitol syrup, polydextrose, among others. • Natural and synthetic modified or unmodified POLYMERS used to increase the mechanical, thermal and barrier resistance of foams: proteins, polysaccharides, polyesters, polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyacrylate, hydroxyethyl methyl cellulose, polyurethane, poly (lactic acid), polyethylene, wax, latex, elastomer, gelatinized starch, carboxy methyl cellulose, gum, gelatin, polyhydroxy alkanoates, caprolactone, polycaprolactone, poly (hydroxybutyrate), cellulosic polymers, starch, starch, chitosan, cellulose derivatives, lignin, cellulose fiber, natural fibers, polyvinyl pyrrolidone, resistant starch, regenerated cellulose, natural gums, polystyrene, polyvinyl chloride, ABS, polypropylene , epoxy, cornstarch, potato starch, rice starch, pea starch, rice husk, curauá, wood powder, manioc starch, biri starch, taro starch, ginger starch, sweet potato starch, so re others.

Material Preparation Material preparation, for ease of understanding, is detailed in case by case form: CASE 1 - ALL STARCH OR CELLULOSE OR MIXTURES ARE PUT IN WATER SAUCE

Soak all starch in water up to 1: 9 by weight. Wait a minimum of 15 minutes and then let it decant, dripping off the water after decanting. It is not necessary to dry the material. • Separate about 3 to 10% by weight of the wet starch and add water about 9 times the weight of this separated material and then heat to gel formation, with the starch gelatinization temperature varying accordingly. with the source, for example, the potato starch gelatinization temperature is 56 to 66 ° C, that of cassava starch between 62 and 66 ° C, that of rice between 61 and 77 ° C, and that of maize at 56 to 72 ° C; and the proportion of added water will vary depending on the forming process that will be used, generally from 1: 1 to 1: 9 by weight starch / cellulose and water. • Mix the gel obtained with the additives (if applicable) and the remaining dry material. • Forward to extruder or injector.

If the cellulose is larger than the starch, all the cellulose is placed in the initial gel forming sauce, respecting the initial ratio of 1: 9, by weight of cellulose and water, and then the dry starch is added. (smaller amount), always preparing the gel of that product in greater quantity.

EXAMPLE 1. Allow the starch or cellulose or mixture thereof to soak in excess water in a 1: 9 weight ratio at room temperature for a minimum of 15 minutes using up to 75% by weight starch or cellulose or of the mixture; allow to decant, dripping off the water after decanting. 2. With 3 to 10% by weight of this starch or cellulose or mixtures thereof, a gel is prepared by heating at varying temperatures according to the botanical source of the starch. at 66 ° C, cassava starch at 62 to 66 ° C, rice at 61 to 77 ° C, and maize at 56 to 72 ° C) or cellulose at 50 to 100 ° C in excess of water at 2 to 90 % by weight of the mass depending on the process to be used, ie extrusion or injection. In case of starch / cellulose mixture, the recommended temperature for the starch source should preferably be used. 3. Mix the gel with the rest of the formulation, i.e. the remainder of starch or cellulose or mixture, a plasticizer at 0.5 to 20% by weight, preferably 1 to 3%, and other additives such as lubricant, preservative. , etc. 4. Pass the mixture in an extruder at a temperature of 50 to 250 ° C.

If starch or cellulose or their mixtures were not soaked, a rise in temperature could result in brittle and brittle parts. The invention allows for temperature increase in the extruder, especially when necessary to combine starch or cellulose with complementary materials such as polyesters, which require high processing temperatures. 5. Press the extruder out mass to obtain the desired object, such as trays, pots, etc.

If the dough tends to stick to the molds, silicone may be used in the mold or teflon molded, and there is no need to add products to facilitate removal of the mold part.

Optionally, in step 1, only the amounts of starch or cellulose or mixtures needed to prepare the dough and not the gel, so up to 72% by weight of starch or cellulose or mixtures, may be soaked in excess water. followed by preparation as indicated.

Case 2 - Only starch or cellulose or gel-generating mixtures are soaked in water • Leave 3 to 10% of starch or cellulose or mixture in water, up to 1: 1 to 1: 9 by weight. After a minimum of 15 minutes of soaking, heat to gel formation. In case of starch / cellulose mixture, heat at a variable temperature according to the botanical source of the starch. • Mix the gel with the additives (if applicable) and the remaining dry material. • Forward material to extruder or injector.

In the case of a larger amount of cellulose than starch, cellulose is placed in the initial gel-forming sauce, respecting the initial ratio of 1: 9 by weight of cellulose and water, and then the rest of the dry material is added thereafter. preparing the gel of that in greater quantity.

EXAMPLE 1. Soak 56 g of starch in 504 g of water (1: 9), decant for at least 15 minutes and drain the water. 2. Prepare the gel by mixing 3 g of starch in 29 g of water and warming to gel formation, the starch / water ratio may vary depending on the extrusion process to be used. 3. Mix the gel with the starch from step 1, glycerin (2g) and bagasse (10g).

IMPROVEMENT OF STARCH AND CELLULOSE PROCESSABILITY IN EXTRUDER Starch or cellulose hydration by soaking in excess of water for a minimum of 15 min is able to retain water within the starch or cellulose granules, avoiding loss of moisture. water during the extrusion process is therefore avoiding starch darkening, loss of mechanical and barrier properties (solubility and water absorption) of the formed product, even when processed at high temperatures in the extruder barrel.

The most significant results of the new technical effects obtained by the process for biodegradable objects are presented in Tables 1 to 5.

Table 1 - Increased bearing capacity of higher extruder temperatures without burning or caramelization. Appearance is the most important quality factor, especially in the packaging sector, being evaluated by different attributes. Coloring is the most attractive quality attribute for the consumer as it is associated with the cleanliness and freshness of the packaged product. There are many reactions that occur during extrusion at elevated temperatures that affect the color of the final product, among them the most common are non-enzymatic darkening reactions (Maillard reaction and caramelization) and pigment degradation, with darkening being affected. by high temperature and solids concentration (the higher the solids concentration, the higher the caramelization). The light color of the end product in extruding sour flour (starch) with soy flour, for example, is only achieved when the material is extruded at intermediate temperature conditions in the extrusion zone, between 25 ° C and 40 ° C. , and lower percentage of soy flour. In this case, soy, which has no starch, was used as a source of cellulose, as it has about 40% protein, 20% lipid, 5% minerals and 34% carbohydrates (sugars, fiber and oligosaccharides). The biodegradable foamed material obtained here is able to withstand higher temperatures in the extruder without burning or caramelizing, since the starch or cellulose hydration by immersing it in water generates liquid retention inside the sugar granules, avoiding The loss of water during the extrusion process, even at high temperatures, avoiding the detrimental increase in the concentration of solids, since the increase in the amount of water promotes its dilution.

The foams become more resistant without the need to add materials for this purpose.

The results presented in Table 2 show the compressive strength of foams in relation to soaking time when compared to non-biodegradable material such as Styrofoam.

Table 2 - Resistance of foams to compression in relation to the time of soaking or non-biodegradable material (Styrofoam) High temperatures during the extrusion process may cause the moisture of the formed material to decrease, and since water has plasticizing power, the material resistance Compression formed is directly related to the moisture content of the material. Unlike most plastic materials, starch and bagasse have hydrophilic characteristics, and their mechanical properties are altered by this characteristic. In this invention, the starch or cellulose granules are capable of absorbing water and retaining it even when subjected to high processing temperatures, thus achieving fully biodegradable foamed materials with high moisture content and therefore excellent mechanical properties. without the need to add materials for this purpose.

Table 3 - Loss of production (breaking of trays and pots) during the compression molding process With the loss of water during the extrusion process, since water is responsible for mass expansion and foam formation, more mass is produced. necessary for the formation of an entire foam, and more mass is required for the formation of a package.

Table 4 - Foam density in relation to soak time or non-biodegradable material (Styrofoam) Water and temperature are responsible for steam generation that causes mass expansion and foam formation (rigid structure) at the extruder outlet. Material produced with larger amounts of water expands more easily during the extrusion process, generating less dense and more flexible foams.

In this invention, the foams are less dense because starch or cellulose granules are capable of absorbing water and retaining it even when subjected to high temperatures, generating materials with greater amounts of water and greater expansion power.

Table 5 - Solubility of Foam in Water In this invention there is a decrease in the solubility of the biodegradable foam material due to the water trapped inside the starch or cellulose granules, to be able to lubricate the extruder screw, avoiding further occurrence of mechanical degradation. of starch granules. Extrusion of wheat, banana and rice flour under high temperatures, low water contents and increased screw speed results in greater degradation of starch granules, which contributes to increased solubility of the material in water (Carvalho, RV; Ascheri, JLR; Cal-Vidal, J.; Science and Agrotechnology, v. 26, No. 5, pp. 1006-1018, 2002. Hashimoto, JM; Grossman, MVE; International Journal of Food Science and Technology, v. 38 , No. 5, pp. 511-517, 2003. Guha, M .; Ali, SZ; Bhattacharya, S.; Journal of Food Engineering, v. 32, pp. 251-267, 1997).

In addition to these technical effects, we also have that the extruder mass does not need to be immediately pressed into pots or trays, but can be stored for some time before the compression molding process.

In the prior art, the mass produced with dry starch or cellulose, ie without the use of at least one of the starch, cellulose or mixture components immersed in water, must be pressed immediately upon exiting the extruder, otherwise there will be formation of a halo in the center of the product, weakening the material. In this invention, the formulation, once homogenized on a shaker, can be stored for up to 24 hours prior to the extrusion process. Formulations prepared without the use of at least one of the starch, cellulose or water-immersed ingredients should be used immediately. The shelf life of the dough before compression molding is directly linked to the amount of water present in the formulation and the amount of water lost by the dough as a function of storage temperature and humidity, since water is responsible for starch expansion. and by obtaining the foam. Losing water loses the power of expansion and more mass is needed to fill the lack of water.

In addition, water has the function of plasticizing foam, with low moisture foams tending to be brittle and poorly resistant. This tendency, known as the phenomenon of starch aging or retrogradation, produces a form of beta starch, as in hardened old bread, which decreases the compressive strength of foams over time. The foam exited from the extruder, formulated with water-immersed starch or cellulose, is wetter even when subjected to high temperatures, having a longer life than foam produced with dry starch, ie without being immersed in water.

PREPARATION TESTS AND FORMULATION RESULTS

Example 1 Cassava starch and sugarcane bagasse foams were prepared by three methods: a) by soaking 5% (w / w) of the total amount of cassava starch starch for 30 minutes prior to the extrusion process for the production of the gel; (b) pouring 5% (w / w) of the total amount of sugarcane bagasse soaked for 30 minutes before the extrusion process for the production of the gel; c) with raw material used without any treatment, ie not soaked.

Formulations tested (percentages in m / m): Formulation 1: sugarcane bagasse (13%), starch (55%), water (30%), glycerol (2%) as plasticizer.

Formulation 2: sugarcane bagasse (55%), starch (13%), water (30%), glycerol (2%) as plasticizer. The raw material, gel and the remaining starch were homogenized in an industrial agitator, processed in a single screw extruder with four heating zones, ranging from 80 ° C to 180 ° C (zone 1 = 80 ° C, zone 2 = 100 ° C, zone 3 = 120 ° C and zone 4 = 180 ° C) from the feed zone at the die outlet and rotation 25 to 50 rpm whereupon the thermoset mass obtained (250 ° C for 1 minute, pressure 150 kPa) in tray format.

The trays were analyzed and the results regarding their mechanical resistance to compression and flexibility (Table EX1-1); density (Table EX1-2); process temperature in extruder (Table EX1-3); yield loss, that is, incomplete, blistered or cracked trays (Table EX1-4) and water solubility of trays (Table EX1-5) are presented below.

Table EX1-1. Mechanical resistance of the trays.

Table EX1-2. Tray density.

Table EX1-3. Process temperature (extrusion).

Table EX1-4. Production loss - Tray-shaped pressing.

Table EX1-5. Solubility of trays in water.

Trays made from soaked raw material for 30 minutes prior to the extrusion and thermoforming process are more mechanically resistant, less dense, withstand high temperatures without burning or caramelizing and are less soluble in water than those produced without treatment. of the raw material, ie without soaking the starch and / or bagasse in water.

WET PRODUCT STORAGE TEST

About 50 g of sugarcane bagasse was soaked in 450 ml distilled water for 1 hour at room temperature. After 1 hour, the pomace was mixed with 20 g of cassava starch, 20 g of water, 5 g of coconut oil as plasticizer and 5 g of talc as lubricant. Excess water was decanted off and the mixture was homogenized, processed in a twin screw extruder with three heating zones (50 ° C, 80 ° C and 120 ° C) from the feed zone at the die outlet, rotating at 100 ° C. , 150 and 200 rpm and thermoset for 30 seconds at room temperature and 50kPa pressure in a pot shape for storing about 250 g of pitted plums. The same procedure was adopted for the preparation of pots without any treatment of the raw material, ie the bagasse was not soaked. . The pots made from untreated bagasse softened and broke and could not be used for storing wet products, while the pots made from bagasse soaked for 1 hour endured and remained intact until the plums rotted.

VISUAL ASPECT TEST, MECHANICAL PROPERTIES AND SOLUBILITY OF POTATO STARK CUPS

About 30 g of potato starch was soaked in 270 g of water for 15 minutes at room temperature. Then the starch was mixed with 30 g of sugarcane bagasse, 30 g of water, 5 g of sorbitol as plasticizer and 5 g of talc as lubricant. The mixture was homogenized and processed in a twin screw extruder with five heating zones (80 ° C, 100 ° C, 120 ° C, 140 ° C and 200 ° C) from the feed zone to the die outlet at a speed of 60 ° C. rpm The same procedure was adopted for the preparation of pots without any treatment of the raw material, ie potato starch was not. soaked. The mass extruded from the extruder was stored for two days before the compression molding process. After this period, the dough was thermosetted at 250 ° C and 100 kPa pressure for 1 minute in the shape of cups (12 cm high X 6 cm in diameter), and the cups made with soaked potato starch identified as Type 1 and the cups made of potato starch not soaked as Type 2. About 250 ml of orange juice was added to all cups. The glasses remained with the juice for 5 hours, were emptied and then the already dry glasses were submitted to mechanical resistance, solubility and visual appearance analyzes. Results are shown in table EX3-1.

Table EX3-1. Visual appearance, mechanical properties and solubility of potato starch cups. NOTE: * Similar to Styrofoam cups. ** halo in center of product indicating caramelized material.

Potato starch cups soaked for 15 minutes are whiter and much more like styrofoam cups, more mechanically resistant and less soluble than untreated potato starch cups. It was observed that type 2 cups burned when subjected to a temperature of 250 ° C for 1 minute. STORAGE TESTS (Mass percentages) About 9% water and 15% glycerol were mixed with 76% previously washed and dried sugarcane bagasse (premix 1).

About 9% water and 15% glycerol were mixed with 76% sugarcane bagasse previously soaked for 45 minutes (premix 2).

These two premixes were stored for 24 hours in a refrigerator and then both were processed in a single screw extruder equipped with four heating zones, whose temperatures were maintained at 60, 70, 90 and 120 ° C from the feeding zone to the outlet. of the die, with thread rotation ranging from 20 to 40 rpm. The extruded samples were immediately pressed at 200 ° C and 92 kPa for a period of 1 minute in tray format.

Since the shelf-life before dough extrusion and compression molding processes is directly linked to the amount of water present, low moisture foams tend to be brittle and poorly resistant, as observed in trays made from premix 1, presenting brittle trays and little resistance to compression when applied force of 22.4 ± 1.8N.

With premix 2 very mechanically resistant trays were obtained (compressive strength = 39.8 ± 1.6 N), even those produced later after being stored for 24 hours in a refrigerator (compressive strength = 38.9 ± 1, 3 N), showing that by soaking the cellulose, it is possible to store the dough prior to the extrusion and thermoforming processes or any other process already known in the plastics industry, thereby obtaining a constituent technical effect of improving this invention. WATERPROOF TESTS (mass percentages) About 10% water and 20% glycerol were mixed with 70% previously washed and dried cassava starch (premix 1).

About 10% water and 20% glycerol were mixed with 70% manioc starch previously soaked for 40 minutes at room temperature (premix 2).

The premixes were processed in a four-zone twin screw extruder, maintained at 90-100 ° C, 100-120 ° C, 120-140 ° C and 140 - 160 ° C, from the feed zone to the outlet. matrix at an extrusion speed of 75 rpm and continuous feed. The material was obtained as a tape with the aid of a 30 mm x 1 mm matrix coupled to the extruder outlet, and immediately pressed at 200 ° C and pressure of 92 kPa for a period of 1 minute in the form of tray.

Forty trays, 20 made from premix 1 and 20 from premix 2, were used to store water-and-fat-free products in the form of about 250 g mozzarella and ham separately.

Trays made from premix 2 (10 with cheese and 10 with ham) resisted storage, ie did not break, crack and soften even after the ham and cheese deteriorated (sour odor, presence of a viscous liquid, slightly altered color, tending to gray or green, and presence of dark spots).

Trays produced with premix 1 (10 with cheese and 10 with ham) did not resist storage, with 15 trays softening and 5 trays breaking after two days of storage, showing that trays produced with cassava starch, kept Sauce before extrusion and thermo pressing processes are more mechanically resistant and can be used for the storage of wet products. RECYCLING TESTS (mass percentages) About 10% water and 20% glycerol were mixed with 70% previously washed and dried sugarcane bagasse pulp (premix 1).

About 10% water and 20% glycerol were mixed with 70% sugarcane bagasse previously soaked for 1 hour at room temperature (premix 2).

The premixes were processed in a three-zone single screw extruder maintained at 80-90 ° C, 100-120 ° C and 120-140 ° C from the feed zone to the die outlet at extrusion rate. 50 rpm and continuous power. The material was obtained as a tape with the aid of a 30 mm x 1 mm matrix coupled to the extruder outlet, and immediately pressed at 200 ° C and pressure of 92 kPa for a period of 1 minute in the form of tray.

After a period of 30 days, the trays produced with premixes 1 and 2 were crushed in an industrial blender and reused in the production of new trays in the following proportions: • a) about 10% water and 20% glycerol were mixed with 50% of previously washed and dried sugarcane bagasse pulp and 20% of the ground material from premix 1 above (premix 1); (B) about 10% water and 20% glycerol were mixed with 50% previously washed and dried sugarcane bagasse pulp and 20% of the ground material from premix 2 above (premix 2) and • c) about 10% water and 20% glycerol was mixed with 50% sugarcane bagasse previously soaked for 1 hour at room temperature and 20% of the ground material from premix 2 above (premixed). mix 3).

The premixes were re-processed in a three-zone single screw extruder maintained at 80-90 ° C, 100-120 ° C and 120-140 ° C from the feed zone to the die outlet at 50 rpm extrusion and continuous feed. The material was obtained as a tape with the aid of a 30 mm x 1 mm matrix coupled to the extruder outlet, and immediately pressed at 200 ° C and pressure of 92 kPa for a period of 1 minute in the form of tray.

All trays produced (20 made with premix 1, 20 made with premix 2 and 20 made with premix 3) were used to store chicken thighs (250g) at 5 ° C in a refrigerator. in each tray). The 20 trays made from premixes 2 and 3 resisted storage, that is, they did not break, did not crack and did not soften even after the chicken had deteriorated (sour odor, presence of a viscous liquid, slightly altered color, tending to gray or green, and presence of dark spots). Trays produced with premix 1 did not withstand storage, with 18 trays cracked and 2 softened, showing that trays produced with sugarcane bagasse pulp, soaked prior to extrusion and thermo-pressing processes, are more mechanically resistant and can be used to obtain new products.

Claims (10)

1 - “PROCESS FOR PREPARATION OF BIODEGRADABLE AND RECYCLABLE MATERIAL FOR MANUFACTURE OF THERMOFORMED OBJECTS”, being the biodegradable and recyclable material formed by starch, cellulose or mixtures thereof, leaving part or all of the starch or cellulose soaked in excess water in the ratio 1: 1 to 1: 9 by weight starch / cellulose: water at a temperature of up to 100 ° C for a minimum of 15 minutes for preparation of the formulation or a gel which, mixed and homogenized to the rest of the material by extrusion or injection will form the foam to be compressed for molding into the desired shape of thermoformed and recyclable objects, and optionally include plasticizers and additives such as dyes or pigments, lubricants, cross-linking agents, preservatives. , fillers, thickeners, stabilizers and natural or synthetic polymers to the gel or formulation formed. 2. A process for preparing biodegradable and recyclable material for the manufacture of thermoformed objects according to claim 1, wherein the formation of the gel or formulation is carried out at a variable temperature according to the botanical source of the starch. 3. A process for the preparation of biodegradable and recyclable material for the manufacture of thermoformed objects according to claim 1, characterized in that the starch is up to 75% (w / w) with a particle size in the range of 0.5 pm. at 110 pm, A process for preparing bio-digestible and recyclable material for the manufacture of thermoformed objects according to claims 1 and 3, characterized in that the starch is a cassava starch in the range from 4.0 to 35.0 pm, or starch originates from other botanical forms such as corn (3.0 to 23.0 pm); biri (25.0 to 45.0 pm); arrowroot (9.0 to 42.0 pm); sweet potato (2.0 to 42.0 pm) and ginger (15.0 to 20.0 pm), or mixtures thereof, all in a percentage of 30 to 70% (w / w). 5. A process for the preparation of biodegradable and recyclable material for the manufacture of thermoformed objects according to claim 1, characterized in that the cellulose is up to 75% (w / w), with a fiber size of 3x10- 4 cm to 1 cm. 6. A process for the preparation of biodegradable and recyclable material for the manufacture of thermoformed objects according to claims 1 and 5, characterized in that the cellulose is sugarcane bagasse in the amount of 5 to 30% (m / m) or other cellulosic fibers of vegetable origin such as wood (pine, eucalyptus, fir), cotton, jute hemp, ramie, flax, mallow, coconut, banana, straw, rice husk, ramie, flax, cashew nut, Brazil nut, açaí , palm, abaca, curacao, whether or not treated. Process for the preparation of biodegradable and recyclable material for the manufacture of thermoformed objects according to claim 1, characterized in that the amount of water used in the formulation of the material is 2% to 90% (w / w) 8. A process for preparing bio-digestible and recyclable material for the manufacture of thermoformed objects according to claim 1, wherein one embodiment is to soak all the starch or cellulose in water in a ratio of 1: 9. by weight, wait a minimum of 15 minutes and then allow to decant, draining the water after decanting, and drying of the material is not necessary; separate part of the wet material, heat it to gel formation and mix the obtained gel with the unused dry material and the wet material, add the additives, mix the formulation and send it to the extruder. A process for the preparation of biodegradable and recyclable material for the manufacture of thermoformed objects according to claims 1 and 8, characterized in that only the amounts of starch or cellulose or mixtures required for the preparation are excessively soaked in water. preparing the dough and not the gel, i.e. up to 72% by weight of starch or cellulose or mixtures, followed by the preparation as indicated in claim 8. 10. A process for the preparation of biodegradable and recyclable material for the manufacture of thermoformed objects according to claim 1, wherein another embodiment consists of placing only starch or cellulose or mixtures in the amount of 3 to 10%. by weight of the gel-generating material in a 1: 1 to 1: 9 gravy of water and, after a minimum of 15 minutes of soaking, heat to gel formation, then mix the gel with the additives and the rest of the dry material and route the material to the extruder or injector.