Green environmentally friendly PVA water-soluble film is a novel green packaging material. The main raw material is polyvinyl alcohol with a low degree of alcoholysis. It uses the film-forming properties, water solubility and degradability of polyvinyl alcohol, and adds various additives. Such as surfactants, plasticizers, release agents and so on. Water-soluble film products are green environmental protection packaging materials, and have been recognized by environmental protection departments in Europe, America, Japan and other countries. At present, BOD and COD are mainly used as environmental protection indicators at home and abroad. Japan ’s relevant authorities have determined that the biochemical oxygen consumption (BOD) of polyvinyl alcohol is much smaller than starch. The amount of BOD measured by American Air Products ’biodegradation of Airvol ’s PVA products for 5 days is less than 1% of the initial total BOD. Biological tests have proven that polyvinyl alcohol is neither toxic nor prevents the growth and reproduction of microorganisms, and has no impact on wastewater treatment and environmental sanitation. Relevant department microbial decomposition test research also shows that polyvinyl alcohol can be almost completely decomposed, which makes COD very low. As far as the degradation mechanism is concerned, PVA has both water and biological degradation characteristics. Firstly, it dissolves in water to form a glue solution and infiltrates into the soil, which increases the soil viscosity, air permeability and water retention, and is especially suitable for sandy soil modification. PVA in the soil can be broken down by bacteria isolated from the soil, a single cell strain. A symbiotic system composed of at least two kinds of bacteria can degrade polyvinyl alcohol: one kind of bacteria is an active bacteria of polyvinyl alcohol, and the other is a bacteria that produces substances required for PVA active bacteria. The secondary alcohol's oxidation reaction catalyzes polyvinyl alcohol, and then the hydrolase cuts the oxidized PVA main chain, further degrades, and finally degrades to CO2 and H2O.
From the perspective of classification, PVA water-soluble films can be divided into fast-dissolving films, medium-soluble films and hardly-soluble films. These three types of products are widely used in daily life. Among them, fast-dissolving films can be used in clothing embroidery substrates, agricultural seed bags, herbicide packaging bags, cleaning supplies, chemical product packaging, and hospital washing bags. ; Medium soluble film is mainly used in wigs, food and cosmetics packaging bags; while insoluble film is mainly used in advanced textiles, plastic outer packaging bags, packaging cushion air cushions, books, paper protection films. It can be said that water-soluble plastic packaging film is one of the most successful green environmental protection materials developed in recent years at home and abroad.
PVA water-soluble film product features Although environmental protection has long been the mainstream of today's society, in order to be recognized by the market, the product itself must have better characteristics than similar products. PVA water-soluble film has significant advantages in many aspects.
Compared with other film products, the physical properties of PVA water-soluble film make it extremely competitive. PVA water-soluble film is superior to other films in terms of gloss and transparency. Compared with commonly used cellophane (PT) and PVC film, its reflectivity is more than 20%, and its light transmittance is more than 50%. In terms of barrier properties, PVA water-soluble film has strong permeability to moisture and ammonia gas. Its moisture permeability is similar to cellophane, which can ensure that no mist is generated when packaging hot and wet items. At the same time, it is resistant to oxygen and nitrogen. , Hydrogen, helium, argon and carbon dioxide have excellent barrier properties. Under dry conditions, its oxygen permeability coefficient is the lowest among various resin films. The barrier ratio to oxygen under atmospheric pressure is about the commonly used polyethylene. 1000 times the film and 300 times the polypropylene film. This allows the PVA water-soluble film to keep the components of the packaged product and its own odor intact. Excellent fragrance retention and anti-sublimation properties of the packaging make the use of PVA water-soluble film packaging, which can not only maintain the fragrance of the packaging, but also prevent the packaging from being affected by external odors.
Due to the good toughness and high tensile strength of PVA water-soluble film, its tear resistance ranks first among all kinds of films. Its superior biaxial tensile strength, resistance to twists and turns is 10 times that of other films, and good weather resistance, which guarantees that the product has Longer service life. Unlike many plastic films, which have strong charging properties, PVA water-soluble films have almost no static electricity. In the process of using film packaging products, they will not cause plasticity reduction or electrostatic dust collection due to static electricity. At the same time, it has excellent Oil resistance (vegetable oil, animal oil, mineral oil), fat resistance, resistance to organic solvents and carbohydrates, these two characteristics make PVA water-soluble films have a wider range of application prospects in the packaging of many special products.