Material production – this is how natural plastic is created
Renewable raw materials as the basis for bioplastics – material production
The basis for the production of natural and biodegradable plastics (bioplastics, natural plastics, bioplastics) are renewable raw materials that are processed into a compound through technical processing. Compounds are granules that can then be further processed. Depending on the intended use, they are obtained from either corn starch or lactic acid.
However, no bioplastic can be formed with starch or lactic acid alone: In the course of processing, a number of additives therefore have to be added. Typical substances used by NaKu for our natural plastic are, for example, minerals, resins, oils or sunflower waste. The sunflower pods naturally contain oils that act as a lubricant.
Extraction of starch (mainly corn starch in NaKu):
Starch is an organic compound that occurs naturally in many plants. In our part of the world, the raw materials used are primarily corn starch and potato starch. But there are also many other plants that produce starch, such as rice or Jerusalem artichoke.
More specifically, starch is a polysaccharide (multiple sugar). The corn starch is obtained by leaching. All starchy parts are further and further broken down and washed out of the cells by filtration and centrifugation steps until pure corn starch is obtained. After drying, the native corn starch is available as a powder. On an industrial scale, starch is used, for example, as a starting material for printer paper, glue, glue or the like.
Extraction of lactic acid:
Lactic acid is a natural substance that occurs, for example, in yoghurt, sauerkraut or in the human body, for example in the muscles. The human organism can easily break down lactic acid, so as a natural plastic it is completely harmless.
The starting material for the production of lactic acid is the corn starch obtained from the corn plant. The lactic acid is obtained through fermentation. This means that the corn starch is fermented to lactic acid with the help of bacteria. Other products we use every day, such as sour milk products or yoghurt, are made using a similar process.
Polymerization to PLA:
In order to obtain a material like the compound for further processing, the lactic acid has to be polymerized. Lactide, a short-chain lactic acid compound, is converted to polylactide (PLA), a long-chain compound. This happens at high temperatures between 140 and 180°C and under the influence of catalytic tin compounds. This creates a thermoplastic material with high strength.
Compounding Process:
The thermoplastic raw material is still too sticky for further processing. To obtain usable granules, a special compounding process is used. This is a mixing process in which the individual components (thermoplastic raw material and additives such as minerals and oils) are blended in the extruder. The extruder outputs a long stream of bioplastic, which is then cut into granules. The granules can be starch, PLA, or another bioplastic raw material.
FAQ - Frequently Asked Questions
How is the base material for NaKu bioplastic produced?
The base material, a so-called compound granulate, is obtained from renewable raw materials such as corn starch or lactic acid. Corn starch is extracted from plant parts and ground into powder. Lactic acid is produced by fermenting corn starch with bacteria.
What is the next step after extracting the raw materials?
After extracting the corn starch or lactic acid, the thermoplastic raw material is mixed with various additives such as minerals, resins, and oils. This process takes place in an extruder, which converts the material into usable granules.
What is the finished granulate used for?
The finished granulate made of starch, PLA or another bioplastic raw material serves as the basis for the further production of various NaKu products such as bottles and bags.
