EP2776513A1

EP2776513A1 - Method for producing a milk protein based plastic material (mp based plastic material)

Info

Publication number: EP2776513A1
Application number: EP12799514.0A
Authority: EP
Inventors: Anke Domaske
Original assignee: QMILCH IP GmbH
Current assignee: QMILCH IP GmbH
Priority date: 2011-11-12
Filing date: 2012-11-12
Publication date: 2014-09-17
Also published as: WO2013068597A4; US20150013569A1; WO2013068597A1

Abstract

The invention relates to a milk protein based plastic material produced according to a plastic material shaping method, known by a person skilled in the art and the literature, in which at least one protein, which is obtained from milk and which can be thermally plasticized, is plasticized using a plasticizing agent, such as for example water or glycerol at temperatures of between room temperature and 140 °C, subjected to mechanical stress and subsequently retreated according to a production method, known to person skilled in the art and literature, to form moulded bodies.

Description

Process for the preparation of a milk protein plastic (MP - plastic)

Processes for the production of polymeric plastics are described in the literature and known to the person skilled in the art.

German Patent 202004004732 describes an edible and biodegradable, multi-layered and peelable casein composite packaging material for food and non-food. The patent describes an outer plastic separation layer, a middle case separation layer, and a gel separation layer. A process is described, which is characterized not only by the 3 separating layers, but also by a swelling time of 5 hours. Then the mixture is stirred again for 2 hours. Then a granulate is extruded and packed. The granules are then further processed by film blowing into films. The plastic film must be removed by the consumer before consumption.

German Patent 4309528 describes a process for producing casein foils or foils, processes for their preparation and their use. However, this invention describes swelling of the casein powder for 30-90 minutes before it is extruded. Here an uneconomic and non-industrial process is described. In addition, the use of glutaraldehyde is described again. Glutaraldehyde, however, is a toxic substance that is harmful to the environment and to health. In addition, the invention describes that films or film tubes as packaging material for non-hygroscopic, powdery products such as coffee, tea and spices, or fatty products such as lard, tallow and fatty oils, as well as for tablets and flavored, dry products, are useful as seed bands and adhesive tapes and for lamination of paper. Accordingly, the water resistance of the foils described is minimal.

Despite these known methods, it has hitherto not been possible to impart to polymeric plastics from renewable raw materials (especially protein-based), without the addition of acrylates and fossil raw materials, a necessary water or moisture resistance which is a prerequisite for plastics. The use of acrylates and fossil raw materials should be largely avoided for health reasons, if possible.

The invention is based on the invention to eliminate the disadvantages mentioned above and to give plastics, preferably from renewable raw materials (especially protein-based) and preferably without the addition of acrylates and fossil raw materials, a necessary water or moisture resistance.

The object is achieved by the method according to the claims.

The invention helps to reduce the processing time and the use of chemicals and to produce the plastics preferably and largely from renewable and / or biodegradable raw materials. At the same time, water and energy consumption are to be reduced and productivity increased. The present invention is directed to plastics made by a continuous or discontinuous process of a composition, preferably comprising destructured milk proteins, biodegradable thermoplastic polymers and plasticizers.

In this case, at least one protein obtained from milk or a protein produced by bacteria is optionally plasticized together with a plasticizer at temperatures between room temperature and 140 ° C under mechanical stress.

The invention is based on the finding that the milk proteins and in particular casein and its derivatives can be plasticized and polymerized in this way. It is preferably provided that the plasticizing takes place at temperatures up to 140 ° C. For an even more gentle treatment, the protein is intensively mixed or kneaded together with a plasticizer and subjected to mechanical stress. The required plasticizing temperature is significantly reduced by the plasticizer.

The milk protein is preferably casein or lactalbumin or soy protein.

The milk-derived protein can be produced in situ by precipitation from milk. For this purpose, according to a first procedure, the milk in mixture with rennet, other suitable enzymes or acid introduced directly as a flocculated mixture in the process or the pressed flocculated protein can be used wet. According to another possible procedure, a separately recovered, optionally purified, pure or mixed protein, i. a protein fraction from milk are used, e.g. dried as a powder.

The protein fraction can also be produced by ultrafiltration or by cell cultures. In addition, milk proteins, for example, with additional salts such as sodium, and potassium can be modified in further processing steps, so that a casein arises.

The milk protein used according to the invention can be mixed with other proteins in an amount of up to 70% by weight, based on the milk protein. For this example, other albumins, such as ovalbumin and vegetable proteins, in particular lupine protein, soy protein or wheat proteins, in particular gluten come into question.

The mixture of solvent and proteins is heated, usually under pressure conditions and shear, to accelerate the crosslinking process. Chemical or enzymatic agents can also be used to destructivate and crosslink the milk proteins, oxidize or derivatize, etherify, saponify, and esterify. Usually, milk proteins are destructured by dissolving the milk proteins in water. Fully distucted milk proteins are formed when there are no lumps that influence polymerisation. A plasticizer can be used in the present invention to destructivate the milk proteins and allow the milk proteins to flow, ie to produce thermoplastic milk proteins. The same or other plasticizers can be used to increase melt processability, or two separate plasticizers can be used. The plasticizers can also improve the flexibility of the final products. The plasticizers are substantially compatible with the polymeric components of the present invention so that the plasticizers can effectively modify the properties of the composition. As used herein, the term "substantially compatible" means that the plasticizer, when heated to a temperature above the softening and / or melting temperature of the composition, is capable of forming a substantially homogeneous mixture with milk proteins.

The plasticizer is preferably water, which is used in an amount between 20 and 80% based on the weight of the protein, preferably in an amount of about 40 to 50 wt .-% of the protein content. Instead of the water or in a mixture with this, other plasticizers, in particular alcohols, polyalcohols, carbohydrates in aqueous solution and in particular aqueous polysaccharide solutions can be used.

Specifically, the following plasticizers are preferred: hydrogen bridge-forming, organic compounds without hydroxyl group, eg urea and derivatives, animal proteins, eg gelatin, vegetable proteins, such as cotton soybeans, and sunburn proteins, esters of producing acids, which citric acid, adipic acid, stearic acid, oleic acid, hydrocarbon-based acids, eg ethylene acrylic acid, ethylene maleic acid, butadiene acrylic acid, butadienemalic acid, propylene acrylic acid, propylene maleic acid, sugars, eg maltose, lactose, sucrose, fructose, maltodextrin, glycerol, pentaerythritol and sugar alcohols, eg malite, mannitol, sorbitol, xyiitol, polyols, eg hexanetriol, glycols and the like, also mixtures and polymers, sugar anhydrides, eg sorbitan, esters, for example glycerol acetate, (mono, di, triacetate) dimethyl and diethyl succinate and related esters, glycerol propionates, (mono, di, tri-propionates) butanoates, stearates, Phthalatester. These are non-limiting examples of hydroxylic plasticizer. Important influencing factors are the affinity to the proteins, the amount of protein and the molecular weight. Glycerol and sugar alcohols are among the most important Softeners. Parts by weight of plasticizers are, for example, 5% -55%, but may also be in the range of 2% -75%. Any of alcohols, polyols, esters and polyesters may be used in proportions by weight, preferably up to 30% in the polymer blend.

Of particular importance for the polymer blend are the Theological properties, so that a good processing is possible. Strain-strain solidification is necessary to form a stable polymer structure. The melting temperature is usually in a temperature range of 30 ° C to 190 ° C. Additional temperatures should be lowered with diluents and plasticizers.

The biodegradability of the polymers, i. their decomposition by living things and their enzymes is an important property of polymeric MP plastics.

Biodegradable thermoplastic polymers suitable for use in the present invention include, for example, lactic acid polymers, lactide polymers, glycolide polymers, including their homo- and copolymers, and mixtures thereof; aliphatic polyesters of dibasic diols / acids; aliphatic polyesteramides, aromatic polyesters, also of modified polyethylene terephthalates and polybutylene terephthalates; polycaprolactones; aliphatic / aromatic copolyesters; Poly (3-hydroxyalkanoates), including those copolymers and / or other -valerates, - hexanoates and alkanoates, polyesters and dialkanoyl polymers, polyamides and copolymers of polyethylene / vinyl alcohol.

As a biodegradable thermoplastic polymer for this invention are, for example and preferably suitable: polyvinyl alcohol and copolymers, aliphatic amide and Este reo polymers consisting of monomers such as dialcohols (1, 4-butanediol, 1, 3-propanediol, 1, 6- Hexanediol, etc.) or ethylene and diethylene glycol, aliphatic polyester amides, (aliphatic esters are formed with aliphatic amides) or other reactions such as lactic acid with diamines and dicarboxylic acid dichlorides, diols with carboxylic acids, caprolactone and caprolactam, or ester prepolymers with diisocyanates, dicarboxylic acids, especially Succinic acid, oxalic acid and adipic acid and their esters, hydroxycarboxylic acids, lactones, aminoalcohols (eg ethanolamine, propanolamine), cyclic lactams, - aminocarboxylic acids (eg aminocaproic acid), dicarboxylic acids and diamines (eg Salt mixtures of dicarboxylic acids) and mixtures thereof. Polyesters such as oligoesters can also be used.

Polybuylensuccinat / adipate copolymer; polyalkylene; Polypentamethylsuccinate; Polyhexamethylsuccinate; Polyheptamethylsuccinate; Polyoctamethylsuccinate; Polyalkylene oxalates, e.g. Polyethylene oxalate and polybutylene oxalate polyalkylene succinate copolymers, e.g. Polyethylene succinate / adipate copolymer and; Polyalkylene oxalate copolymers, e.g. Polybutylene oxalate / succinate copolymer and polybutylene oxalate / adipate copolymer; Polybutylene oxalate / succinate adipate terpolymers; and mixtures thereof are non-limiting examples of aliphatic polyesters of dibasic acids / diols, e.g. from polymerizations of acids and alcohols or ring-opening reactions and are suitable for the production of a polymer.

Another possibility for use in the production of biodegradable polymers are aliphatic / aromatic copolyesters. These are derived from dicarboxylic acids (and derivatives) such as malonic, succinic, glutaric, adipic, pimelic, azelaic, sebacic, fumaric, 2,2-dimethylglutaric, suberic, 1,3-cyclopentanedicarboxylic , 1,4-Cyclohexanedicarboxylic, 1,3-cyclohexanedicarboxylic, diglycol, itaconic, maleic, 2,5-norbornanedicarboxylic, 1,4-terephthalic, 1,3-terephthalic, 2,6-naphthoic acid -, 1, 5-naphthoic acid, ester-forming derivatives and mixtures thereof and diols, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetra ethylene glycol, propylene glycol, 1, 3-propanediol, 2,2-dimethyl-1, 3-propanediol, 1, 3- Butanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, thiodiethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2, 2,4,4-tetramethyl-1,3-cyclobutanediol and combinations thereof formed in a condensation reaction. Examples of such aliphatic / aromatic copolyesters include blends of poly (tetramethylene glutarate-co-terephthalate), poly (tetramethylene glutarate-co-terephthalate), poly (tetramethylene glutarate-co-terephthalate), poly (tetramethylene glutarate-co-terephthalate), poly (tetramethylene glutarate). co-terephthalate-co-diglycolate), poly (ethylene glutarate-co-terephthalate), poly (tetramethylene adipate-co-terephthalate), an 85/15 blend of poly (tetramethylene succinate-co-terephthalate), poly (tetramethylene-co-ethylene-glutarate-co terephthalate), poly (tetramethylene-co-ethylene-glutarate-co-terephthalate). The processability of the protein mass can be modified by other materials to influence the physical and mechanical properties of the protein mass, but also of the final product. Non-limiting examples include thermoplastic polymers, crystallization accelerators or inhibitors, odor masking agents, crosslinking agents, emulsifiers, salts, lubricants, surfactants, cyclodextrins, lubricants, other optical brighteners, antioxidants, processing aids, flame retardants, dyes, pigments, fillers, proteins, and their alkali salts. Waxes, adhesive resins, extenders and mixtures thereof. These adjuvants are bound to the protein matrix and influence their properties.

Salts can be added to the melt. Non-limiting examples of salts include sodium chloride, potassium chloride, sodium sulfate, ammonium sulfate, and mixtures thereof. Salts can affect the solubility of the protein in water, but also the mechanical properties. Salts can serve as binders between the protein molecules.

On the other hand, lubricants can affect the stability of the polymer. These can reduce the stickiness of the polymer and reduce the coefficient of friction. Polyethylene would be a non-limiting example.

The physical properties of the polymer composition can be influenced by other proteins, e.g. vegetable proteins such as sunflower protein or animal like gelatin. Water-soluble polysaccharides and water-soluble synthetic polymers, such as polyacrylic acids, can also affect the mechanical properties.

Monoglycerides and diglycerides and phosphatides, as well as other animal and vegetable fats can influence and promote the flow properties of the biopolymer.

Inorganic fillers are also among the possible additives and can be used as processing agents. Possible examples, without limiting the use, are oxides, silicates, carbonates, lime, clay, limestone and kieselguhr and inorganic salts. Stearate-based salts and rosin can be used to modify the protein mixture. Amino acids, the components of the proteins and peptides may be added to the polymer composition to enhance particular sheet structures or mechanical properties. Without limitation, glutamic acid, histidine, trytophan, etc. are mentioned as examples.

Other additives include enzymes, surfactants, acids, serpins, both phenolic plant molecules, which can contribute to crosslinking and to improve the mechanical properties, and can cause resistance in water and proteases.

Other additives may be desirable, depending on the particular end use of the intended product. For example, wet strength is a necessary feature in most products. Therefore, it is necessary to add wet strength resins as a crosslinking agent.

Other natural polymers can also be added as additives. Possible examples of natural polymers, without limiting the choice, would be albumins, soy protein, zein protein, chitosan and cellulose polylactide "and" PLA ", which can be used in an amount of 0.1% -80%.

In addition to natural polymers, other synthetic polymers, such as, inter alia, polyvinyl alcohol, as well as polyesters, or ethers, such as polyethylene glycol, Aldeyhde, such as. Glutaraldehyde and acrylic acids are used.

These include non-degradable polymers, which are used depending on the end use of the plastic, including thermoplastics that can be used for copolymerization, such as e.g. Polypropylene, polyethylene, polyamides, polyesters and copolymers thereof. Other high molecular weight polymers are also possible.

Carbohydrates and polysaccharides, as well as amyloses, oligosaccharides and chenodeoxycholic acids can be used as further auxiliaries and additives.

Salts, carboxylic acids, dicarboxylic acids and carbonates, as well as their anhydrides, salts and esters can also be used as additional crosslinkers. hydroxides, Butyl esters, as well as aliphatic hydrocarbons, are further ways to cross-link molecules and form macromolecules.

The addition of other substances is not excluded. Specifically, additives and auxiliaries, such as lipophilic, hydrophobic, hydrophilic, hydroscopic additives, gloss modifiers and crosslinkers may be provided. The additives and auxiliaries should overall not exceed a proportion by weight of preferably about 30% by weight, based on the protein. As lipophilic additives, vegetable oils, alcohols, fats and can be chosen, which readily hydrophobicize the polymer composition during plasticizing. Furthermore, waxes and greases can be used which add strength to the polymer composition. As waxes are preferred carnauba wax, beeswax, candelilla wax and other naturally derived waxes.

After the formation of the plastic, the polymer may be further treated or the bonded fabric treated. A hydrophilic or hydrophobic surface treatment can be added to adjust the surface energy and chemical nature of the fabric. For example, hydrophobic resins or the polymer can be treated with wetting agents to facilitate the absorption of aqueous liquids. A bonded fabric may also be treated with a topical solution containing surfactants, pigments, lubricants, salt, enzymes, or other materials to further adjust the surface properties of the plastic.

In order for the plastic to meet the increased requirements of improved properties for a particular purpose, they are made according to the previously known and described manufacturing processes. The polymer composition is produced according to the continuous or discontinuous process known from the literature and to the person skilled in the art, preferably by mixing or extruding a premix with the addition of additives or mixing the polymer composition by metering in the raw materials and additives during mixing or extrusion.

The preparation of the plastics may be known to those skilled in the method z. B. by injection molding or extrusion process. The process, which uses water as a solvent and plasticizer, prevents any labor law, toxicological and licensing difficulties.

Due to the plasticization, the polymer composition corresponds to a polymer in which the materials are converted by heating in a plastic state and thus deformed. The temperature exceeds the glass transition temperature of the protein, so that it passes from the amorphous to the rubbery plastic state.

After the exit of the polymer composition, e.g. from the extruder, this can be further processed directly, preferably to a plastic in the extrusion process.

Alternatively, the polymer composition can be processed further directly after leaving the nozzle or in at least one later processing step to form a shaped article.

In a further development of the invention, the polymer composition can also pass through a bath prior to curing, this procedure is not particularly preferred and usually not required. Alternatively, the polymer composition may be subjected to a spray treatment after exiting the nozzle. Here, for example, Gtättungsmittel, waxes, lipophilic or crosslinking agents can be applied to the surface of the polymer composition. In the case of crosslinkers, those given above are preferred, that is to say generally different salt solutions, preferably calcium chloride solution, dialdehyde starch solution, or aqueous lactic acid. An alternative to a gas treatment or an ice treatment or a drying and blowing treatment or an ion treatment or a UV treatment or an enzyme treatment, and a renaturation by salts or esterification, etherification, saponification or other crosslinking, and a needling and Wasserstrahlverfestigungsverfahren and the Kaladrieren etc be subjected to.

The obtained plastic and the products made therefrom can be used for all conceivable purposes. Non-limiting examples include all types of components used in automotive, construction, window, furniture, electronics, sports, toys, machinery and equipment, packaging, agriculture and the like Safety technology, paper, adhesives, medical technology, cosmetics, life science, for example, as dental splints, household items, artificial leather, etc. are processed.

The multi-constituent plastics of the present invention may be in many different configurations. By definition, the "ingredient" as used herein means the chemical species or material. Plastics can have a mono-component or multi-component configuration. The "component" is defined as a separate part of the plastic that is in spatial relationship with another part of the plastic. The resulting plastic can in turn be applied to a matrix.

The advantages achieved by the invention include the fact that in the manufacture of plastics according to the invention the reduction of harmful substances and environmentally harmful substances during the process and on the plastics itself is made possible. In addition, the plastic is biodegradable.

In addition, significant resources of energy, water, time and manpower can be saved, which increases environmental protection and improves profitability. The particularly advantageous properties of the milk protein plastics are attributed to firming structural changes (textural structure) during plasticizing.

The plastics are preferably made by an extrusion process to allow the highest possible productivity. All known to those skilled in the art and from the literature manufacturing method for plastics described are possible without exception. Essential to the invention is the preparation of a homogeneously plasticized polymer, preferably a biogenic biopolymer, which is preferably biodegradable. Unfortunately, no plastics could be developed on this basis to date, which are water-resistant and sufficiently proteases; -acid; and alkali-resistant. Preferably, the use of petroleum-based raw materials and / or organic solvents, especially in plastics for baby products, dental splints, implants and cosmetics, to name just a few examples, should be reduced or even ruled out. For plastics, which are preferably made from renewable raw materials, with a proportion of milk proteins and are characterized by properties such as water resistance, high protease resistance, sufficient mechanical properties, such as tensile strength, tensile strength, furthermore - flame retardant, elastic, anti-allergic, antibacterial and biodegradable In addition, there is the possibility of influencing the properties of the protein plastics by changing the raw material additions according to the requirements of the intended use.

Examples

In the following the invention will be described in more detail with reference to an embodiment. The embodiment is for illustrative purposes only and is not intended to limit the invention. The person skilled in the art can find further possible embodiments by varying the parameters on the basis of this exemplary embodiment and with the aid of his specialist knowledge.

Example 1: Preparation of a milk protein-polymer mass. The extrusion takes place with a twin-screw extruder type 30 E of the company. Collin with a diameter of 30 mm. The production of the plastic takes place by means of extrusion technology.

The heating is carried out over 4 barrel heating temperature with the following sequence ^D 65 C, 74 ° C, 75 ° C, 60 ° C:

The casein powder is added via a vibrating trough. A hose pump is used to add water. By further metering devices, the additives are added. The polymer composition is processed into a plastic by an extrusion process. The extrusion process and the processing of the polymer composition into a plastic is additionally illustrated by FIG. About a metering device 1, the raw materials are added to the extruder 2 and mixed the polymer composition. Subsequently, the extruded polymer enters a nozzle 3 and passes through a blowing 4.

Claims

Process for producing a milk protein plastic, formed from a homogeneous polymer based on proteins obtained from milk, which are plasticized with the addition of heat and a plasticizer and under mechanical stress.

Method according to claim 1, characterized in that the polymer mass is processed using an extruder.

Method according to claim 1 or 2, characterized in that the milk protein plastics are produced continuously or discontinuously.

Method according to one of the preceding claims, characterized in that the milk protein plastics are preferably made from renewable raw materials and are biodegradable.

Method according to one of the preceding claims, characterized in that at least one protein obtained from milk is plasticized and further processed together with a plasticizer under mechanical stress.

Method according to one of the preceding claims, characterized in that the plasticizing takes place at temperatures of up to 40 °C.

Method according to one of the preceding claims, characterized in that the protein obtained from milk is either produced in situ by precipitation from milk or is used in the form of a previously separately obtained and possibly prepared protein or a protein fraction.

Method according to one of the preceding claims, characterized in that the proteins obtained from milk are obtained from bacteria.

Method according to one of the preceding claims, characterized in that the proteins obtained from milk are processed by gas treatment or filtration be won.

10. The method according to any one of the preceding claims, characterized in that the proteins obtained from milk, in particular casein, lactalbumin, or soy protein, are obtained from goat's milk, sheep's milk, cow's milk or soy milk.

11. The method according to any one of the preceding claims, characterized in that the plasticizer is selected from the group: water, aqueous carbohydrate solution and in particular aqueous polysaccharides, oligosaccharides, proteins, alcohol, polyalcohol, fats, acids, amino acids, peptides, salts, cations, Enzymes or mixtures of these agents, as well as their oxidation.

12. The method according to any one of the preceding claims, characterized in that further additives and auxiliary materials are added to the starting material to be plasticized, optionally by mixing before or during plasticizing.

13. The method according to any one of the preceding claims, characterized in that the plastic is dried and post-treated by passing through a bath or a spray treatment or a gas treatment or an ice treatment or a drying and blowing treatment or an ion treatment, needling and water jet consolidation processes or one UV treatment, infrared treatment or enzyme treatment, as well as renaturation by salts or alcohols, esters and ethers, esterification, etherification, saponification or further crosslinking.

14. The method according to any one of the preceding claims, characterized in that biopolymers, preferably biodegradable biopolymers, are used.

15. The method according to any one of the preceding claims, characterized in that polysaccharides, preferably biodegradable polysaccharides, are used.

16. The method according to any one of the preceding claims, characterized in that carboxylic acids, dicarboxylic acids and carbonates, as well as their salts and esters, as well as fatty acids, preferably biodegradable, are used for the mixture.

17. The method according to any one of the preceding claims, characterized in that the polymer mass is destructured, oxidized or derivatized, etherified, esterified or saponified by chemical or enzymatic means.

18. Method according to one of the preceding claims, characterized in that corresponding amino acids are used for the mixture.

19. The method according to any one of the preceding claims, characterized in that the milk protein plastic varies in terms of its mechanical properties by adding, pre- or post-treating with protease inhibitors, in particular enzymes, surfactants, acids, serpines, phenolic molecules from plants and polysaccharides becomes.

20. The method according to any one of the preceding claims, characterized in that the milk protein plastic is processed into granules, composite materials, in particular with fibers, in particular natural fibers, nanoparticles and nanofibers, or matrix systems.

21. Milk protein plastic, which contains a thermally-mechanically plasticized milk protein, in particular produced using a method according to one of claims 1 to 20.

22. Use of a milk protein plastic according to claim 21 for the production of components for vehicle and aircraft construction, the construction industry, window construction, the furniture industry, the electrical industry, sports equipment, toys, mechanical and apparatus engineering, the packaging industry, agriculture or security technology , paper, adhesives, medical technology, cosmetics, life science, as dental splints, household items, artificial leather.