DE4446054A1 - Biodegradable textile contains thermoplastic starch - Google Patents

Abstract

Textile prod. for technical and non-technical applications contains thermoplastic starch (I) or a polymer mixt. contg. (I). (I) is obtd. by destructurising or plasticising native starch with plasticiser(s) (II), with simultaneous redn. of the water content to less than 5 wt.% w.r.t. the starch/(II) mixt. Pref. (II) is glycerol and/or sorbitol. The polymer mixt. also contains a polyolefin and a block copolymer as phase agent and/or a polyolefin and an ethylene acrylate maleic anhydride copolymer.

Description

The invention relates to high-strength threads or fibers as they for example for particularly durable fabrics, ropes or Networks are used, and a method for their manufacture position.

In the manufacture of e.g. B. of synthetic fibers it is known these directly from a melt or over several intermediate steps to spin threads and then to raise stretch the strength. From the plastic indu strie is also the stretching of synthetic thermoplastic known materials. Ent all of these plastic fibers however, substantial portions do not fully biolo gisch degradable components, which are used to achieve certain Properties can be attached.

From WO 90/05161 it is known to be a thermoplastic Processable starch with the help of conventional plastic processing processing method, as well as from such To produce starch fibers, but the fibers are flat  if not or not completely biodegradable Be components included.

The object of the invention is to completely biodegrade bare threads or fibers with very good mechanical load availability.

This task is ge with the features of the claims solves.

In the solution, the invention is based on the basic idea high-strength threads or fibers from an extrudate of a thermo plastically processable starch and optionally one biodegradable polymer mixture based on a ther to manufacture plastic starch. An inventive high-strength thread is therefore completely biodegradable. The raw materials modified in an extruder are discharged as a film and cut into threads or directly discharged as threads to increase their strength ver stretches and then wound up or in an in-line Processed directly into fabrics or the like. The optimal processing temperatures of the invention Threads, especially during stretching, are approx. 30 to 40 ° C and are therefore much lower than that of synthetic thermoplastic materials, their processing tion temperature is usually 100 ° C. During the The macromolecules are stretched at approx. 30 to 40 ° C an orientation that indicates an increase in tear strength, too increasing transparency and increasing stability Effects of water and water vapor. Surprisingly takes maximum tear strength through this treatment of the thread by about a power of ten compared to an unstretched thread with the same cross-section. Likewise Surprisingly, the elasticity of the thread increases renewable raw materials after stretching by approx Power of ten from. It is also advantageous that such Fo  lines and threads have antistatic properties and are conductive.

The invention will be explained in more detail below: modified mixture of the starting materials in an extruder made of thermoplastically processable starch and a biolo cally degradable polymer mixture based on a thermopla starch can first be processed into a film, as described for example in DE-B-42 28 016, and on finally cut into threads and stretched, or directly in an in-line process via a multi-hole nozzle Individual threads extruded, as described in DE-C-43 17 696, and be stretched immediately afterwards. The stretching the threads are monoaxial at room temperature or at tem temperatures up to a maximum of 60 ° C, but preferably at 30 to 40 ° C in air or in another medium, e.g. B. in one Stretch bath of water and / or solvent or also in another gaseous medium. The stretching or Stretch ratio is essentially between 1: 4 and 1:20, preferably at 1: 8.

Offer as a film when extruding the raw material mixture the following options for further processing: Di right behind a film extrusion system (blow or flat film) the film is continuously in-line in individual cases the cut, the resulting threads afterwards the above process parameters stretched in-line and on tents wound on spools as tear-resistant tapes. The so The resulting biodegradable tapes can be put into tapes Chenform can be used directly, or on a white machine starting from the wound individual coils one step further to fabrics, nets, textiles or ropes are processed. In addition, the which single coils in a two-stage process over the Intermediate step of the treeing process said fabrics, nets, Make textiles or ropes.  

Furthermore, the film starting material can be rolled up in cut into threads in one operation, this in-line stretched above process parameters and opened up together to be reared. The resulting warp beams, consisting of a variety of tear-resistant individual threads can then in another step on fabrics, nets, textiles or process ropes.

Likewise, one can be monoaxial according to the above process parameters stretched film as starting material (as roll goods) be applied. This film is made on one machine in one Cut and tear to individual tear-resistant threads Fabrics, nets, textiles or ropes processed or as Ribbon individually wound.

After a further processing possibility, the Fo lien raw material in roll form in one operation Threads cut, according to the above process parameters stretches and then in-line on the same machine processed into fabrics, nets, textiles or ropes or individually wound as a ribbon.

The advantageous properties of the threads according to the invention should first be clarified on the basis of foil tensile tests carried out. A film strip, made of a biodegradable material made of a thermoplastic starch and a degradable aliphatic polyester (BIOFLEX BF 102) with the dimensions length / width / thickness of 50 mm / 2 mm / 0.025 mm was in a ratio of 1: 8 at a temperature stretched from 35 ° C. During several tensile tests it was found that the tensile strength or tensile strength of this film strip with an applied tear force of 12.8 to 14.8 N is between 216 and 250 N per mm². In contrast, the tensile strength of a comparably tested, non-stretched film strip with a tear strength of 1.3 to 1.9 N. is only approx. 25.1 to 38.1 N per mm². Following performed Folienzugversuche 1 and 2 illustrate these results with reference to the dazugehö ring respectively Fig. 1 and 2 for drawn yarns, wherein the sample thickness, A _O h is the sample cross-sectional area F _{max is} the maxi male tear strength of the sample strip, δ _{max is} the maximum elongation relative strength are the sample cross-sectional area, S- (F _max ) the amount of elongation of the sample in mm and ε- (F _max ) the elongation in% of the original measuring length. The comparative test 3 shows, with reference to FIG. 3, the results in the case of tensile stress on undrawn threads, the tensile force at which the stretch begins (F _stretch ) and the tensile stress acting in the process were additionally determined.

1. Film tensile test with stretched film Experimental parameters

Sample width 2 mm
Measuring length 50 mm (corresponds to the distance between the pressure plates)
Initial force at the start of the measurement 0.2 N
Fractional criterion 2 N
Speed up to preload 500 mm / min
Test speed 500 mm / min
All three samples were stretched at a temperature of 35 ° C in a ratio of 1: 8.

Test results

2. Film tensile test with stretched film Experimental parameters

The test parameters correspond to those of the 1st film pull ver such.

Test results

3. Film tensile test with undrawn film Experimental parameters

The test parameters correspond to those of the 1st film pull ver suches.

Test results

As the experiments show, the fibers according to the invention can or threads with the help of an otherwise in the manufacture of Chemical fibers usual stretching process are processed. The stretching of the threads is already very effective at 35 ° C and significantly improves tear resistance. Furthermore, the entire production of the threads including Ver stretch in a continuous and one-step process the procedure. The threads or Fa from completely biodegradable materials NEN, for example, in their manufacture as a ribbon and / or monofilament as the end product for inland applications shaft and gardening (plant ribbon or similar), as Ver packing material (packaging cords and tapes, etc.) or as an intermediate product on warp beams or single spools Further processing to completely biodegradable net zen, fabrics, textiles or ropes. Furthermore, especially solid, fully biodegradable fibers and / or Ropes by twisting or braiding the ribbon / monofilament getting produced. These particularly strong bands and / or Ropes can be made into nets, fabrics and textiles of all kinds process further.

Applications for products of this type are, for example:

• - Packing bags (Raschel or net bags etc.) with open NEN or semi-dense or dense structures for e.g. B. Kar potatoes, citrus, onions, etc., toys, house stationery and other products of all kinds,
• - Light protection fences for trees or plants of all kinds Reforestation / replanting in the forest or garden construction, e.g. B. against game browsing or as erosion protection,
• - Fly protection nets for doors and windows or mosquito nets,
• - Tree packaging (e.g. fir trees, etc.) and nets for Root ball in gardening and landscaping,  
• - tearproof garbage bags,
• - filter fabrics of all kinds,
• - weldable banding in the form of a tear-open band len, strapping bands, etc.,
• - Sports nets (badminton, table tennis, volleyball or similar),
• - Lattice fabric for keeping pets, e.g. B. rabbit hutch, Pigeon crates etc.,
• - Protection nets of all kinds, e.g. B. for personal protection, stone Impact protection, erosion protection, also in vineyards, in the Agriculture and horticulture,
• - Net roll goods for hardware stores etc. (DIY needs),
• - products for fish farming and fishing / inland fishing,
• - Textiles of all kinds, e.g. B. tablecloths, windbreak, sun protection, tarpaulins, awnings, etc.
• - Agrotextiles, e.g. B. Floor covers for early harvest, Wind and sun protection,
• - fibers as dry fleece (air layed paper),
• - Thermobonded nonwovens,
• - textile packaging tape z. B. for carton strapping, pallet strapping etc.,
• - Protective clothing or disposable clothing in clean rooms, e.g. B. Hoods, gloves, shoe covers, overals and smocks.

Further advantages of films and threads from renewable Raw materials especially from thermoplastic starch and from buildable polymer mixtures based on thermoplastic Strengths are their antistatic properties and conductivity speed. This should be based on measurements of the surface resistance be made clear. The empirical value is that Materials with a surface resistance below 10¹¹ Ω, ge measure according to DIN 53482, no disturbing or dangerous experience electrostatic charges.

The surface resistance was also measured in accordance with DIN 53482 the high-resistance measuring device type HM 307, manufacturer FETRONIC, Lan genfeld.

Measurement results:
at 50% relative humidity and 20 ° C:
BIOFLEX BF 102: 3 × 10⁸ Ω
BIOFLEX BF 102: 6 × 10⁸ Ω
at 30% relative humidity and 20 ° C:
BIOFLEX BF 102: 10 × 10⁹ Ω
BIOFLEX BF 102: 10 × 10⁹ Ω

A commercially available antistatic film that is comparatively tested, reached the following surface resistance values:

at 50% relative humidity and 20 ° C: 3 × 10⁸ Ω
at 30% relative humidity and 20 ° C: 10 × 10⁹ Ω

Due to these special antistatic material properties are products based on thermoplastic starches also suitable for the following applications:

• - As packaging material and material to prevent static charges,
• - for electrical and electronic devices, products and components,
• - for explosive, highly flammable and flammable mate rialien and products z. B. Big bag film inner bags for powder products to prevent dust explosions when filling and prevent emptying and
• - Packaging materials and materials for fireworks and explosives fabrics.

Another application example for the invention Threads in the textile sector are their processing into diapers products. Such a fully biodegradable win del can be structured as follows.

The outer shell forms a biodegradable film, such as it is described for example in DE-B-42 28 016, the is laminated onto a soft cellulose layer. Further soft cellulose layers, the SAP products (superabsorbents as starch graft polymers) and strongly water-borne are sucked, are introduced. The inner core consists of a fleece made of biodegradable material. The win del in the above structure can with high produc tion speed because the pre-product te as rolls and bringing the one together individual layers by sealing processes. By z. B. The diaper shape and size is punched out of the roll mat rial manufactured. Fixing of the edges and the rubber thread on the elastic leg and abdomen is done by a heat seal. Adhesive strips or Velcro fasteners are used to attach the front of the diaper to the back part used.  

The threads or fibers according to the invention can also themselves as loose materials such as staple fibers or filament fibers manufactured and made into nonwovens, felts and textile composites are processed. The nonwovens are consolidated by needling, stitching, swirling, melting or you the fibers. The fleeces can also be added Threads, fabrics or knitted fabrics are reinforced, e.g. B. same term or dissimilar degradable materials, such as. B. Cellulose fibers, cotton plant fibers, kapok, sisal, Flax, hemp, jute, kenaf, ramie, coconut and wool fibers or silk. The aforementioned nonwovens, felts and textiles bundles can be used to make filters, Synthetic leather, disposable items such as dusters, cleaning cloths, Diapers, as insulation material for technical or confectionery tional textiles such as B. Protective clothing.

Other textiles, semi-finished and finished products and Finished goods made from it are, for example, lines shaped structures such as yarns, lines, twine, cords, Ropes, threads; sheet-like structures such as adhesive goods, felts, Needle felting, knitwear and knitwear or voluminous structures such as flakes, wadding, filter mats and polishing wadding.

Claims (11)

1. High-strength thread made from renewable raw materials adjustable from an extrudate a thermoplastic processable starch and, if necessary, a biological one buildable polymer mixture based on thermoplastic Strength and by stretching. 2. High strength thread according to claim 1, characterized net that the extrudate is a film that ge in threads will cut. 3. A process for the production of high-strength threads from renewable raw materials according to claim 1 or 2, characterized by the process steps:

• a) continuous extrusion of a thermoplastically processable starch and optionally a biodegradable polymer mixture based on thermoplastic starch as a film,
• b) cutting the film into threads,
• c) drawing the threads with a draw ratio of 1: 4 to 1:20 and
• d) winding up the threads and, if necessary, further processing into fabrics or the like.

4. A process for producing high-strength threads from renewable raw materials according to claim 1 or 2, characterized by the process steps:

• a) continuous extrusion of a thermoplastically processable starch and optionally a biodegradable polymer mixture based on thermoplastic starch as a thread
• b) drawing the threads with a draw ratio of 1: 4 to 1:20 and
• c) winding the threads and, if necessary, further processing into fabrics or the like.

5. The method according to claim 3 or 4, characterized net that stretching at temperatures below 60 ° C preferably at 30 to 40 ° C. 6. The method according to claim 3, 4 or 5, characterized records that stretching in a gaseous or liquid medium takes place. 7. The method according to claim 5, characterized in that the threads are stretched in air or water. 8. The method according to any one of claims 3 to 7, characterized ge indicates that the stretching is carried out monoaxially. 9. The method according to any one of claims 3 to 8, characterized ge indicates that process steps a) to d) or a) to c) run continuously and in one step. 10. The method according to any one of claims 3 to 8, characterized ge indicates that the threads are continuous after stretching nuously and in one step directly to tissues or the like be processed further. 11. Use of high-strength threads according to one of claims 1 to 10 as an end product in landscaping and horticulture and / or as packaging material or for production fully biodegradable nets, fabrics, felts, Nonwovens, flakes, wadding, textiles or ropes with open structures, semi-dense or dense.