1.Environmental safety, complete degradation (up to 10%), and the final products of degradation are CO2 and H2O, which can completely solve the problem of packaging waste disposal;
2. Safe and convenient to use, to avoid direct contact with the packaged goods, suitable for the packaging of harmful substances on the human body;
3. Can accurately measure and prevent waste;
4. Good mechanical properties, heat sealable, high heat seal strength;
5. With anti-counterfeiting function, it can be used as the best weapon for anti-counterfeiting of high-quality products and prolong the life cycle of high-quality products.
First, the production process of water-soluble plastic packaging film High-tech water-soluble packaging film mainly polyvinyl alcohol and starch as the main raw material, add a variety of additives, such as surfactants, plasticizers, anti-sticking agents, etc. The process is different from the traditional plastic film forming process. Its process is: the first use of raw materials made of solid content of 18% to 20% of the water-soluble glue, and then flow coated on the mirror stainless steel belt, after drying the film peeled from the strip, and then to the drying room After drying to the specified moisture, the finished film is obtained by slitting and rolling.
The process flow is shown in Figure 1:
Scraper Metering Temperature Control ↓ ↓
Hydrosol → Filtration → Flow Coating → Drying to Film-─â”
Trimming │
↓ │
Finished product ↠rewind ↠continue to dry to specified moisture content ↠strip ↠┘
↑
Correction tension control
Figure 1 process diagram
Second, the main components of high-tech water-soluble packaging film and its environmental characteristics 1. Chemical composition Water-soluble packaging film is the main raw material of low alcohol content of polyvinyl alcohol and starch, the main chemical composition of C, H, O.
2. Environmental characteristics High-tech water-soluble film products are green packaging materials and have been recognized by the national environmental protection agencies in Europe, America, Japan and other countries.
At present, BOD and COD are used as environmental indicators at home and abroad. After biological tests showed that polyvinyl alcohol is not toxic, it will not stop the growth and reproduction of microorganisms, and has no effect on waste disposal and environmental protection.
As far as the degradation mechanism is concerned, polyvinyl alcohol has both water and biological degradation characteristics. First it dissolves in water to form a glue solution and infiltrates into the soil, which increases the stickiness, air permeability and water retention of the soil, and is particularly suitable for sand soil transformation.
Third, the main performance of high-tech water-soluble packaging film 1. Water-soluble film into a volume of water-soluble film is generally used PE plastic packaging to maintain its specific moisture content unchanged. When the water-soluble film is removed from the PE package, the water content of the water-soluble film changes with the ambient temperature, and its performance changes accordingly until it is balanced.
Table 1 Balanced Moisture of Water-Soluble Packaging Films
2. Anti-static water-soluble film is an anti-static film. Unlike other plastic films, it has good anti-static property. In the process of using water-soluble film packaging products, it will not cause the decrease of its plasticity and static electricity due to static electricity. With dust.
3. Moisture and gas transmission rate The water-soluble film has a relatively strong permeability to moisture and ammonia, but has good barrier properties to oxygen, nitrogen, hydrogen, and carbon dioxide. These features make it possible to keep the ingredients of the packaged products and their own odors.
4. Heat-sealable water-soluble packaging film has a good heat seal, suitable for resistance heat sealing, high-frequency heat sealing, heat sealing strength and temperature and humidity, pressure, time and other conditions, generally 100 ~ 200g/cm.
5. Mechanical properties The mechanical properties of water-soluble packaging films are shown in Table 2.
Table 2 Mechanical properties of water-soluble packaging film (temperature 20°C)
6. Printing performance The water-soluble film can be printed clearly and smoothly with ordinary printing methods, and the printing performance is good.
7. Oil resistance and chemical resistance Water-soluble packaging film has good oil resistance (vegetable oil, animal oil, mineral oil), resistance to fat, organic solvents and carbohydrates. However, strong alkalis, strong acids, chlorine radicals, and other substances that can react chemically with PVA (such as borax, boric acid, certain dyes, etc.) are not recommended for the packaging of water-soluble films.
8. The water solubility of water-soluble water-soluble film is related to its thickness and temperature. Take 25μm thick film as an example. The relevant data are as follows:
Table 3 Water Soluble Film Water Solubility (25μm)
Fourth, the application prospects of high-tech water-soluble packaging film Water-soluble film is widely used, the market is very broad, and has the characteristics of environmental protection, so it has been widely concerned by the developed countries in the world. For example, Japan, the United States, and France have mass-produced and marketed such products. Its users are also well-known big companies, such as Bayet, Henkel, Shell, Agr.Eva, and other large companies have begun to use water-soluble film to package their products.
In China, the market for water-soluble thin films is rising. According to relevant statistics, according to relevant statistical data, packaging films account for 20% of plastic products, which is approximately 309,000 tons per year. Even if the market accounts for 5% of the market, the annual demand will increase. The amount also reached 15,000 tons. Its main applications are the following:
1. Packages for products used in water, such as pesticides, fertilizers, pigments, dyes, detergents, water treatment agents, mineral additives, detergents, concrete additives, photographic chemicals, and chemical reagents for gardening;
2. Water transfer printing, used for the transfer of trademarks and patterns on the special-shaped surfaces of ceramics and electrical appliances;
3. High temperature water-soluble film (insoluble below 40 °C), can be used for clothing and textile packaging, food preservation film, etc., especially the packaging of export products;
4. For seed bags, agricultural nursery, embroidery and so on.
In addition, the main raw material of water-soluble film is polyvinyl alcohol, China is a big country of raw material production, which is extremely beneficial to the market development of high-tech water-soluble packaging film application prospects, and with the development and progress of society, people pay more and more attention To maintain the environment in which we live, especially as our country is about to integrate with the international developed countries, and the environmental protection requirements for packaging are increasing. Therefore, the application prospect of water-soluble films in China must be very broad.
V. Future research topics As a new type of green packaging material, water-soluble packaging film has just begun its research and application in China, and has only 15 years of development history in foreign countries. Therefore, there are many issues that need to be researched and developed, specifically the following aspects: :
1. Quality Control Method Study of Water-Soluble Film Production Due to the unique production technology of water-soluble film, various defects will occur during production, such as bubbles, uneven thickness, thick edges, “fish eyesâ€, perforation, wrinkles, and “cratersâ€. "And so on, the causes of which are very complex. The production of these defects directly affects the application of water-soluble membranes. Therefore, it is necessary to conduct in-depth research.
2. The influence of various components on the water-soluble packaging film and the mechanism of action The various physical and chemical properties of the water-soluble film are the result of the comprehensive action of its various components. In-depth study to explore the impact of various components on water-soluble packaging film and The mechanism of action is of great significance in improving the quality of water-soluble film production, meeting user requirements, and developing new water soluble films.
3. Improvement and improvement of water-solubility film production rate At present, the production speed of the developed water-soluble film production equipment is 4 to 5 meters per minute, and that of similar foreign equipment is around 7 meters per minute, compared to the production of non-water-soluble film equipment by the traditional process method. The productivity is obviously low, which is an important reason for the higher cost of the water soluble film. How to increase the productivity of water-soluble film will be an important research topic in the future.
4. Development of new water soluble membranes and development of new areas for the application of water soluble membranes