Introduction
PVA water-soluble film is a unique product that has recently gained popularity. It is a film made out of polyvinyl alcohol (PVA) that dissolves in water, making it ideal for applications in the daily chemical, medical, construction, agriculture, water transfer printing, pharmaceutical, etc. industries. Its unique properties make it a desirable product for various industries.
Process of PVA water soluble films
PVA water-soluble film is made from PVA, a thermoplastic. The PVA water-soluble films can be made using the blowing and casting process.
Generally, soluble films made by the casting process will have a more uniform thickness. Not only that, the cast film will add less plasticizer, so the heat resistance will be better. We will introduce the casting process here. The casting process of the soluble films mainly includes three steps.
1. Solution preparation
Add the appropriate amount of PVA powder to the water, heat it, and stir to dissolve it entirely. At the same time, some additives, such as plasticizers, lubricants, and stabilizers, can be added to regulate the film’s performance.
2. Film formation
The solution is applied to the substrate by casting, dipping, or coating to form a film. The casting method is a common process: the solution is poured into the mold, and after vibration and leveling treatment, a uniform film layer is obtained.
Step 3: Drying
After the film is formed, it is dried at the appropriate temperature,
The water is evaporated to obtain a dry PVA water soluble film. The temperature and time of drying need to be strictly controlled to avoid deformation or rupture of the film.
Regulation of soluble film properties
It can regulate the properties of PVA films by using additives and controlling the preparation conditions.
- Additives: You can add the plasticizers as demanded to increase the flexibility and ductility of the film. Adding the plasticizer can improve the toughness and tensile strength of the film. Adding the stabilizer can improve the weatherability and heat resistance of the film.
- Preparation conditions: Adjusting the temperature, concentration, PH, and other parameters in the preparation process can affect the crystallinity, transparency, and solubility of the film.
Benefits and Limitations
PVA water-soluble film’s numerous benefits include its ability to dissolve in water, diverse applications, and environmental friendliness. It is transparent and has strong adhesion to the substrate, making it ideal for labeling and packaging applications.
However, there are some limitations as well. It is not very durable and can easily be damaged by abrasion and extreme temperatures.
Common Applications
PVA water-soluble film is commonly used in different industries.
Firstly, it is often used in medical and pharmaceutical applications and is perfect for disposing of hazardous materials. For example, during the outbreak, the water-soluble laundry bag protected the safety of medical workers and avoided cross-infection.
Secondly, when it is used to make the packaging of pesticides, dyes, and cement additives, people no longer need to open the packaging to use these products, which is an excellent way to avoid the process of opening the packaging, powder into the air, affecting human health or polluting the environment. Moreover, it can also prevent the product from remaining in the packaging bag, causing waste.
Thirdly, high-temperature PVA water-soluble films have good tensile strength, elongation at break, and high-temperature resistance and can be used as artificial marble or quartz stone release films.
Fourthly, It is also a blank film commonly used in water transfer technology, which is a good realization of curved surface printing.
In summary, PVA water-soluble film is a unique product with several benefits and limitations. It is an environmentally friendly, water-soluble film perfect for various applications. However, it is essential to consider the product’s limitations before deciding to use it in an application.
Considerations when choosing a water-soluble film
When selecting the proper water-soluble film for a specific application, a few essential considerations must be taken into account. From choosing the right type of film to ensuring compatibility and performance, it’s necessary to understand the various aspects of water-soluble film to make an informed decision.
Considering the water solubility temperature and function.
According to the solubility temperature, PVA water soluble film is mainly divided into cold water soluble , hot water soluble , and high-temperature water soluble film.
Cold water soluble film
Cold water soluble film is mainly used where the packaging does not need to be opened and needs to be dissolved in cold or room temperature water. Like pesticide packaging, dye packaging, laundry coagulant packaging, bait packaging, cement additive packaging, etc. When used to do the packaging of cement additives, the essential requirement of water dissolution time control within a few seconds to 1 minute, which can be achieved by adjusting the formula. Therefore, if your product needs to dissolve in cold or room-temperature water, it must choose cold-water-soluble films.
Hot water-soluble film
If you want the product packaging, will not immediately dissolve in water, but also hope that after using the product, the packaging can be dissolved in water and become biodegradable to achieve the purpose of environmental protection. Then you can consider hot water soluble film, such as our commonly used shopping bags, electronic products packaging bags, etc. It will not dissolve and break under normal temperature conditions and without long-term contact with water. But when you don’t need water soluble packaging, you can dissolve it in water or biodegrade it into CO2 and H2O because it is also biodegradable
High-temperature water soluble film
PVA High-temperature water soluble film is often used to make artificial marble, quartz stone, and prosthesis release film: as a release film, it has the following advantages
1) Good disengagement performance: it isn’t easy to produce blank after de-molding, saving grinding time.
2) High softness and smoothness can better fit the mold and have higher demoulding quality.
3) Good heat resistance.
4) Good mechanical properties: Excellent tensile strength, high elongation at break.
5) Suitable for continuous production and high production efficiency.
Considering from production process
PVA water-soluble film is mainly produced by two methods, namely the blowing film method and the casting method. The soluble film made by the casting method has a more uniform thickness and better heat resistance. Therefore, if it requires that the thickness is uniform and the heat resistance is good, the casting film should be selected. Conversely, you can choose the blowing film.
Conclusion
When choosing the proper water-soluble film for your project, it’s essential to research and ensure you’re selecting the correct type of film for your needs. With the appropriate knowledge and preparation, you can confidently choose a suitable film for any project.
In short, the soluble film is essential for many industries, from manufacturing and engineering to art and design. By taking the time to research and find the correct film for your needs, you can ensure that your project is done right the first time.
