Technology for producing biodegradable plastic products abroad

A large number of garbage bags can achieve rapid biodegradation during land filling. In the PE, PP film to add organic metal composite multi-layer plastic agricultural film, you can get rapid degradation.
ICI uses natural bacteria to produce biodegradable plastic bottles that package shampoos. The bacteria can convert a large amount of glucose into shampoo bottles. Under conditions of aerobic bacteria, they can contact with water, carbon dioxide, and decayed soil. Through natural bacteria and fungi, they can Plastic bottles and plastic films are biodegraded. The company claims that this type of biodegradable plastic is PHBV, which is durable, stable and resistant to water before it is biodegraded.
A large number of modern biodegradable plastics were developed by the Warner-Lambert company, which uses potato starch, rice starch, and wheat starch, and Morris Plains NJ Pharmaceutical Co., Ltd. uses pressure to humidify, heat, and compress starch to form a tough matrix, along with plastics. Take molded and extruded plastic products.
Biodegradable plastics for commercial products on the market use glucoamylase in potatoes or cheese to form lactic acid bacteria. As a biodegradable plastic structure, this structure is different from cereal starch alone in that it utilizes its mediator to degrade plastics. .
The addition of 15% cereal starch polymer to plastics can also degrade plastics. This method uses bacteria to eat grain starch while swallowing plastic residue. However, although plastics are broken into tiny particles, they are still resistant to degradation for many years. The starch additive produced by ADM can rapidly biodegrade plastic film bags and various plastic bags. The characteristics of this biodegradation are: The strand breaks into small pieces and fills the land. In recent years, ADM has been continuously developing new degradable plastics.
The commonly used biodegradable cereal starch groups are 50-52 μm oval potato starch, 36.4 μm wheat starch, 25 μm glutinous and stigma starch, 14.2 corn starch, 5 to 5.6 μm rice starch, and tapioca starch.
The mixture of starch in the polymer is abbreviated as SPE material. The specific gravity of thermoplastics is generally 0.924 to 1.450, while the specific gravity of starch is generally 1.5. When 30% rice starch is mixed in a 50 μm thick PE film, it can promote the invasion of microorganisms while maintaining a certain ambient temperature.
In the LDOE plastic mixed with 60% starch or 50% starch, need to stir 4min, given that LDPE blown film is extremely sensitive to starch mix, so generally take 20% of the mixture, such as short-term use can also add 50% starch, LDPE Molded blow-molded bottles can be mixed with 50% starch, while LDPE braided tape can be mixed with 10% starch, such as φ120mm large screw extruder, die head temperature is 280-300°C, compression ratio is 4:1, cylinder The temperature is 190 °C, while cooling with a cold air flow, 50μm LDPE blown film blended starch is 30%, LDPE molded products mixed with 30% corn starch, LDPE pressed sheet mix 30%.
PP polymer can be generally mixed with 50% starch, PP tape mixed with 15% starch (about 6:1), polyurethane elastomer mixed with 40% starch, PP braided tape, molded product mixed rice starch (its extrusion temperature is 230°C) .
Confirmed foreign reports: If the plastic sheet is buried in compost (depth of 10cm, 60cm, 100cm, depending on the selected depth, the angle is 45 °), after 7 months can be degraded by fungi and bacteria; such as cleaning compost, The surface layer of the 10cm plate, when the temperature is below 52°C, can be degraded by fungi and bacteria for six weeks. If the plastic sheet is buried in the soil (buried at a depth of 40cm), it will be degraded by fungi and bacteria for 4 months, and 1mm thick polyurethane elastic sheet mixed with 40% starch will be buried in the outdoor garden soil (buried at a depth of 5 to 10cm). The cluster of fungi and bacteria on the plates lasted two weeks and they rapidly degraded in four weeks.
Adding a 0.5% concentration of glucose mixture can cause decolorization, small holes, and embrittlement in the plastic box and be degraded by black spores. Adding a glucose mixture with a concentration of 0.1 to 0.5% can decolorize and soften the PVC plastic products and be degraded by the black spores. PE film waste is buried in black soil and will be degraded by anaerobic work. However, anaerobic bacteria will produce hydrogen sulfide (H2S) pollution source. PE waste plastic bottle is buried in soil with a depth of 4.6m. If it is degraded by anaerobic bacteria, it will reach For 4 to 7 years, if the buried plastic film is degraded by aerobic bacteria, it will be 3 to 5 years.
For example, the use of active agents and esters with oxygen-absorbing function and metabolism can change the properties of plastics and make plastics lose weight and accelerate biodegradation.
In addition, the addition of additives to plastics will further accelerate biodegradation.