DE102010054661A1 - Process for the preparation of milk protein fibers and milk protein fiber products derived therefrom - Google Patents

Abstract

There are milk protein fibers with an extrusion process u. a. Manufactured for the textile industry, in which at least one thermo-plasticizable protein obtained from milk is plasticized with a plasticizer such as water or glycerol at temperatures between room temperature and 140 ° C under mechanical stress and spun into fibers through a nozzle.

Description

The invention relates to a process for the preparation of milk protein fibers u. a. for the textile industry, for hygiene products and medical products and the associated milk protein fiber products such as wadding, nonwovens, loose short fibers, yarns, woven and knitted fabrics and other products made with the fiber according to the invention.

State of the art

Milk protein fibers belong to the protein fibers, to which in the broadest sense also the natural products wool and silk count. On an industrial scale, protein fibers have long been known. Casein fibers were already produced in the 1930s. Casein is a protein fraction from the milk of mammals. Casein is made from skimmed milk which is clotted at around 45 ° C with acids at pH 4.6 (the isoelectric point of casein). Alternatively, Lab coagulation is used. The solid components are separated or pressed and washed several times. Finally, it is dried at 50 to 80 ° C to a residual water content of less than 10% ( Römpp Chemistry Dictionary, Georg Thieme Verlag, 19899 at "Casein" ). Casein is a mixture of several proteins, the most important of which are generally referred to as αS1, αS2, β and κ (cow's milk). Since the white to yellowish, slightly hygroscopic casein powder is insoluble in water but soluble in alkalis, it is necessary for the classical production method in the solution spinning process to work in an alkaline environment and then subject the fiber to further treatment steps and baths. The proteins are dissolved in alkalis, filtered, purified, forced through nozzles into an acid bath, stretched and cured with formaldehyde or aluminum sulfate (Römpp, loc. Cit.).

Specifically, in the classical wet spinning process, an aqueous casein solution is adjusted to a pH of 7 to 10 with sodium carbonate, stirred for 24 hours at room temperature and degassed before further processing in vacuo. The solution is then extruded into a coagulation bath containing aluminum sulfate octadecahydrate, sodium chloride and sulfuric acid. Subsequently, the milk fiber is cured for 24 hours in a hardening bath with sodium acetate trihydrate and formalin solution at a pH of 5.5. Thereafter, the fiber is cleaned 24 hours under running water from residues of the curing bath and dried at room temperature. The pollution caused by the coagulation bath and the water consumption are very high. In addition, this process is very time consuming, the process takes about 60 hours.

From the DE PS 905 418 For example, curing baths are described which correspond to the above.

Object of the invention

The invention has for its object to avoid the disadvantages mentioned above and reduce the processing time. At the same time, the water and energy consumption should be reduced.

Inventive solution

The object is achieved by the method according to claim 1. In this case, at least one protein obtained from milk is optionally plasticized together with a plasticizer at temperatures between room temperature and 140 ° C under mechanical stress and formed or spun through a nozzle into fibers.

The invention is based on the finding that the milk proteins and in particular casein can be plasticized by kneading in the heat and thus processed in the melt spinning process. In melt spinning, the dried meltable raw material is plasticized by heat and preferably pressed through nozzles as a melt by means of gear pumps or extruders. The melt solidifies after removal. The withdrawn thread is wound up or processed as desired. The stripped threads can be stretched before winding and also surface treated.

It is preferably provided that the plasticizing takes place at temperatures up to a maximum of 80 ° C.

For an even more gentle treatment, the protein is intensively mixed or kneaded together with a plasticizer and subjected to mechanical stress. The temperature required for plasticizing takes place is significantly reduced by the plasticizer.

The milk protein is preferably casein or lactalbumin.

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 method procedure, a separately previously obtained, optionally purified pure or mixed protein, i. H. a protein fraction from milk are used, for. B. dried as a powder.

The milk protein used according to the invention can be mixed with other proteins in a proportion of up to a maximum of 30% by weight, based on the milk protein. For this purpose, for example, other albumins, such as ovalbumin and vegetable proteins, in particular lupine protein, soy protein or wheat proteins, in particular gluten in question.

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 water or in a mixture with this, other plasticizers, in particular alcohols, polyalcohols, gum arabic, carbohydrates in aqueous solution and in particular aqueous polysaccharide solutions can be used. The moisture content of the protein fraction may need to be considered.

Specifically, the following plasticizers and associated weight fractions are particularly preferred:
Alcohols and polyhydric alcohols are used in proportions by weight of up to about 10% by weight, based on the protein, and glycerol (glycerol) is particularly preferred. Alternatively, other polyols z. As ethylene glycol can be used. Carbohydrates and polysaccharides are each used in a proportion by weight of preferably between 0.4 and 2% by weight, in each case in 70% strength aqueous solution. Preference is given to starch of various origins, carrageenan, cellulose, in particular carboxycellulose and chitosan.

The addition of other substances is not excluded. In particular, additives and auxiliaries, such as lipophilic additives, gloss modifiers and crosslinkers may be provided. The additives and auxiliaries should overall not exceed a proportion by weight of at most about 30% by weight, based on the protein. As lipophilic additives, vegetable oils can be chosen which readily hydrophobize the fiber during plasticizing. Furthermore, waxes can be used, which give the fiber additional strength. As waxes are preferred carnauba wax, beeswax, candelilla wax and other naturally derived waxes.

Preferred crosslinkers are calcium salts, for example calcium chloride, dialdehyde starch and glucose delta-lactone.

In a particularly preferred embodiment, the plasticization is done with the aid of an extruder, with all selected substances are given as a premix in the extruder, or it will initially only some substances or only the protein abandoned and other substances are in the course of extrusion, d. H. at addition points long added to the screw.

In a particularly preferred embodiment it is provided that the protein is introduced as a dry powder via a funnel at the beginning of the extruder, while the plasticizer and in particular water in a subsequent extrusion stage, the plasticizing zone, is abandoned. Further, it is preferable that all of the dry raw materials are premixed and initially charged while all of the liquid ingredients are admixed downstream thereof. At the exit of the extruder, the extrudate is forced through a die and thereby formed into a fiber.

If the protein is used as a flocculated raw material, the process is preferably carried out so that dehydration can take place along the extruder or the other processing apparatus.

Due to the plasticization, the process corresponds to a melt extrusion. In this thermoplastic extrusion, the materials are converted by heating in a plastic state and on deformed this way. The temperature exceeds the glass transition temperature of the protein, so that it passes from the amorphous to the rubbery plastic state. In the case of particularly heavy walking or kneading, heat is already generated by the mechanical load, so that, if necessary, no heat has to be supplied from the outside. The extrusion then takes place formally already at room temperature. As a rule, however, very specific temperature values are set in the various extruder zones, which allow optimum plasticization. Preferably, extruded in the extruder between 30 and 95 ° C, more preferably between 50 and 90 ° C and more preferably between about 60 and 80 ° C.

Furthermore, it is preferred that the shaped fiber is wound up after exiting the die and dried before and / or after this step.

After the exit of the shaped fiber from the die, it can be cut directly - for example chopped into short fibers - or further processed into staple fibers.

Alternatively, the molded fiber may be further processed into a multiple yarn after emergence from the die directly or in at least one later processing step, in particular twisted, beaten into a batt strand, or further processed into a nonwoven web.

In a further development of the invention, the fiber may also pass through a bath prior to winding, this procedure is not particularly preferred and usually not required. Alternatively, the fiber may be subjected to a spray treatment after exiting the nozzle. Here, for example, smoothing agents, waxes, lipophilic or crosslinking agents can be applied to the surface of the fiber. In the case of crosslinkers, those given above are preferred, ie generally different salt solutions, preferably calcium chloride solution, dialdehyde starch solution, glucose-δ-lactone solution or aqueous lactic acid.

The obtained fibers can be used for all conceivable purposes. They can be used in the same way as conventional textile fibers and can therefore be processed into all types of textiles such as fabrics, fabrics, knitted fabrics, crocheted yarns, ropes, nonwovens, felts, etc. Also, wadding, loose fiber insulation, filters and membranes are obtainable from the fibers according to the invention. The fields of application of the milk fibers according to the invention therefore include u. a. textile technology, building insulation and building materials, hygiene products and, due to their inherent antibacterial properties, medical products such as swabs, filters and membranes.

Therefore, part of this invention is also a milk protein fiber product containing fibers containing a thermo-mechanically plasticized milk protein and obtained in particular by a method according to the invention as described above.

By loose firing of the fibers, for example, wadding or nonwovens can be produced, which can find use, for example, as filling and padding material.

Particularly preferred is when the fibers are twisted into yarns. It is both possible to bind together a plurality of milk protein fibers which were produced by the method according to this invention, and also to twine the milk protein fibers with other natural or synthetic fibers in combination. Elastane, viscose, silk or wool, for example, which can also be spun and / or twisted as a mixture into multiple yarns, can be used as further fibers.

By discontinuous procedure single fibers can be obtained. Also, the fibers can be cut into short fibers or staple fibers.

From the obtained fibers, filaments or yarns, in turn, substances can be produced. Wovens of all types therefore also constitute milk protein fiber products according to this invention.

Advantages of the invention

The advantages achieved by the invention are in particular that in the production of milk protein fibers by the extrusion process, the exclusion of harmful substances and environmentally harmful substances during the process and on the fiber itself is made possible. 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 fibers, as Textile fibers are very well suited, are attributed to strengthening structural changes (Textiärstruktur) during the plasticizing. More detailed knowledge about the mechanics are not yet available.

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 fiber with a thickness of 20dtex.

The extrusion takes place with a single-screw extruder type 30 E of the company. Collin with a diameter of 30 mm. Heating takes place via 4 cylinder heating zones with the following temperature sequence 65 ° C, 74 ° C, 75 ° C, 60 ° C: temperature 65 74 75 60 function material supply water supply plasticizing discharge zone head jet heating zone I II III IV

The casein powder is added via a vibrating trough. A hose pump is used to add water in a ratio of 1: 2 (water: casein). The fiber strength is defined by the nozzle thickness. For example, the fiber may have a thickness of 20 dtex. With the help of a winding machine, the fibers are wound up and dried at room temperature.

The extrusion process is additionally through 1 clarified.

The extruder 1 is over a funnel 2 filled with the casein powder. The casein powder is heated in the extruder. About the water pump 3 the addition of the water takes place as a plasticizer. The final product is through a nozzle 4 pressed. With a suitable winding technology, the fiber strand is wound up and at room temperature on the winder 5 dried.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 905418 [0004]

Cited non-patent literature

• Römpp Chemielexikon, Georg-Thieme-Verlag, 19899 in "Casein" [0002]

Claims (14)

Process for the preparation of milk protein fibers, wherein at least one milk-derived protein is plasticized together with a plasticizer at temperatures between room temperature and 140 ° C under mechanical stress and spun through a nozzle into fibers, characterized in that the plasticizer is selected from the group: aqueous polysaccharide solution, alcohol, polyalcohol, or mixtures of these agents. A method according to claim 1, characterized in that the milk-derived protein is produced by precipitation from milk in situ. A method according to claim 1, characterized in that the milk-derived protein is used in the form of a previously separately obtained protein. Method according to one of claims 1 to 3, characterized in that the milk-derived protein is casein. Method according to one of claims 1 to 3, characterized in that the milk-derived protein is lactalbumin. Method according to one of claims 1 to 5, characterized in that the plastification takes place at temperatures up to 80 ° C maximum. Method according to one of claims 1 to 6, characterized in that further additives and auxiliaries are added to the starting material to be plasticized. Method according to one of claims 1 to 7, characterized in that the plasticizing takes place with the aid of an extruder and the fiber is extruded at the exit of the extruder through a nozzle and thereby formed. Method according to one of claims 1 to 8, characterized in that the shaped fiber is wound up. Method according to one of claims 1 to 9, characterized in that the shaped fiber is dried. Method according to one of claims 1 to 10, characterized in that the shaped fiber is cut immediately after exiting the nozzle. Method according to one of claims 1 to 11, characterized in that the shaped fiber passes through a bath prior to winding. Method according to one of claims 1 to 11, characterized in that the shaped fiber is subjected to a spray treatment prior to winding. A milk protein fiber product containing fibers made by a process according to any one of claims 1 to 13.

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