If you’re a plastics manufacturer or someone working in a related field, you’re probably familiar with the term plasticizer. Plasticizers are a common additive used extensively in plastic production. But do you know what they are, what types exist, and what functions they perform? As a seasoned plastics manufacturer, WEPROFAB will provide an in-depth study of plasticizers so you can understand exactly what plasticizers are present in the parts you customize or purchase.
What is a Plasticizer?
Plasticizers are a type of chemical widely used in polymer materials such as plastics, rubber, and coatings. When processing plastic products, such as Polycarbonate Film or PVC film, adding an appropriate amount of plasticizer can enable the resin with a certain degree of flexibility, elongation, processing performance, and stretch.
By using them in the production of plastic products, they will nest between polymer chains as well and weaken intermolecular forces and thus reduce the rigidity of that material, which makes it more susceptible to shaping or simply more flexible.
Plasticizers typically occur in liquid or solid form. When added to plastics, they make them easier to shape and mold and reduce surface friction. Furthermore, they help adhesives adapt to external pressure and movement, thereby reducing the risk of adhesive failure. They act like your yoga instructor in a yoga studio, helping you bend your back. Plasticizers work in a similar way. By using them, the plastic that you use would be easy to shape.
The History of the Plasticizer
The first man-made plastic was created in 1862. But it took until the end of the 19th century for the concept of “plasticizers” to be introduced.
Plasticizers have gone through a long period of development since their appearance. In the early days, some brand manufacturers primarily used natural camphor and castor oil for plasticization, but these plasticizers were unsuitable for many applications. Then the discovery of triphenyl phosphate marked a significant turning point for the industry. The most important product was the early isolation of tricresyl phosphate, a highly effective and effective product that remains a key component of this plasticizer category today. Tributyl phosphate was once the preferred solvent for cellulose but was later replaced by less volatile products. Over time, triacetin experienced a similar evolution due to its volatility.
Since 1920, the most commonly used phthalates have been commercially used as plasticizers and remain the most widely used type in the 21st century.
Today, the development of new plasticizer formulations is rapidly evolving as plastics become more widely used. If you need to select a plasticizer, understanding its evolution will help you better understand and choose the right one.
What are the Types of Plasticizers?
When choosing plasticizers for plastics, like HDPE rods. It’s crucial to understand them and select the type that’s right for you. Each plasticizer has its advantages and applications. The plasticizers that you can use are primarily divided into these categories: phthalates, citrates, phosphates, and adipates.
Phthalates
Phthalates are one of the most widely used plasticizers worldwide, recognized for their excellent plasticizing properties and economic benefits. They are widely used in soft PVC products such as flooring and artificial leather, significantly improving the material’s flexibility and durability. If you’re looking for a cost-effective plasticizer with excellent processing properties, this may be your ideal choice.
Citrates
If you’re looking for a non-toxic, biodegradable plasticizer, citrates (such as ATBC and TEC) are another option. They are particularly suitable for applications requiring high safety and environmental performance, offering a perfect alternative to traditional phthalates while maintaining excellent plasticizing properties. Recognized as “green plasticizers,” citrates are often used in safety-critical applications such as food packaging and medical devices. Not only are they safe and harmless, but they also provide products with excellent flexibility and durability, making them a benchmark choice for high-end applications.
Phosphates
Phosphate esters (such as TPP and TCP) are suitable for applications that require both flexibility and fire safety. For example, those in building materials, transportation, and electronics. If you’re looking for a flame-retardant plasticizer solution, they’re a good choice. Their unique phosphorus-based structure forms a protective layer at high temperatures, which makes them a promising material for the electronics and building materials industries.
Adipates
Adipate plasticizers (such as DOA and DOS) maintain excellent performance even in extremely low-temperature environments. Their unique special structure effectively lowers the glass transition temperature of plastics, effectively preventing brittle cracking at low temperatures. It is ideal for outdoor products and refrigerated applications. In addition to WEPROFAB, several well-known brands use these plasticizers in their cold-weather products. If you’re looking for a plasticizer that maintains excellent performance even in extremely low-temperature environments, they are your best bet.
Functions of Plasticizers
In addition to being used in different kinds of scenarios, plasticizers also play a crucial role in terms of functionality. The main functions of plasticizers in the main bonding aspects are as follows:
Lowering the glass transition temperature: Plasticizers embed themselves between polymer chains, weakening intermolecular forces. It makes the material more flexible and increases the contact area with the adherend (for example, adding DOP to PVC adhesives improves initial tack). They also prevent plastics from becoming brittle at low temperatures.
Enhancing wettability: Plasticizers raise the surface free energy of your material, which makes it easier for its specific adhesive to spread over the substrate. For instance, making the epoxy resin plasticizable can greatly promote the adhesion to metal.
More flexibility: It feels more ability to improve flexible plastic thanks to the added plasticizers. This molecular structure turns stiff substances into flexible substances, so when you push it, some stickiness is retained.
How to Use Plasticizers?
The use of plasticizers in the plastics manufacturing process requires precise mastery. Proper use can significantly improve the processing properties and quality of your finished product. There are some detailed guides to their application:
Mixing
First, technicians pre-mix your plasticizer with the resin powder at a ratio of 10-50%, based on product performance requirements. This ratio must be precisely controlled based on the desired hardness. For example, soft PVC Rods typically require 30-40% plasticizer, while harder sheets may only require 15-25%.
The mixing process is typically performed in a high-speed blender at 80-100°C. This temperature range promotes the penetration of the plasticizer into the resin particles while preventing premature volatilization. The mixing time is generally controlled for 10-15 minutes, until a uniform dry blend is formed. The order of addition is also crucial: typically, the resin powder is added first, followed by the plasticizer, and finally, stabilizers and other additives.
Melt Processing
During the successive melt processing step, plasticizers help reduce the processing temperature and fluidity. Typically, they can lower the processing temperature by 10-20°C, which results in significant energy savings and reduces thermal degradation of the resin. However, workers control the temperature, which cannot exceed the boiling point of the plasticizer, and the volatilization loss. Depending on the processing method, it is also important to choose the right type of plasticizer that will best serve your application. For example, calendaring is part of your solution as it is better suited for high-MW and low-volatility plasticizers.
Post-Processing
After the product is formed, some plasticizers require a period of aging to fully take effect. This is why your plastic product may be hard when it is first produced, but becomes more flexible after a few days. Throughout the production process, pay special attention to the storage conditions of your plasticizers, keeping them sealed and moisture-proof, and regularly inspect your production equipment, as some plasticizers may corrode metal parts.
Selection Criteria for Plasticizers
Plasticizers are crucial components in plastics. When you select the plasticizer for your plastics, you need to consider multiple factors to find the optimal solution and ensure a perfect balance between product performance, cost, and compliance.
Compatibility
The primary factor determining stability. If compatibility is high, it will mean that your plasticizer is well dispersed throughout the plastic and will not separate out or migrate. Besides, Plasticizers of similar polarity are generally more compatible (the phthalates used with PVC are a striking example). The simple test for you is to observe what happens after mixing the plasticizer with the plastic. If they do not become separated or are cloudy, then they are compatible.
Application Scenario
Another important consideration is the application scenario. Your plasticizers can operate under some natural environments conditions. In the case of food packaging, it requires food-safe plasticizers due to the usage of epoxidized soybean oil or citrate esters. These include trimellitate or high molecular weight polyester plasticizers, which are preferred for use with medical devices that require biocompatibility. As for outdoor plastics, the plastic products used outside are required to have weather-resistant plasticizers, and they may also need UV stabilizers.
Processing Performance
Processing performance is also important. The addition of plasticizers affects the melt flow and processing temperature of plastics. Some plasticizers can significantly reduce melt viscosity and improve production efficiency. However, it is important to ensure that the processing temperature does not exceed the decomposition temperature of the plasticizer; otherwise, product performance will be affected.
Durability Requirements
Durability requirements determine the molecular weight of the plasticizer. High-molecular-weight plasticizers have low migration and are suitable for products requiring long-term use. Plastics used in high-temperature or oily environments require plasticizers with excellent extraction resistance.
Regulatory Requirements
Finally, it is important to confirm that the selected plasticizer complies with relevant regulatory requirements. Restrictions on the use of plasticizers vary across countries and regions, especially for food contact products or children’s products, where regulations are more stringent. Understanding and complying with these regulations in advance can avoid subsequent market access issues.
Conclusion
As you can see, the role, function, and selection criteria of plasticizers in plastic product manufacturing vary widely. If you’re looking for a product that combines high performance with sustainability, we offer a wide range of plastics to meet your needs—from ABS Tube to PET sheet, from food-grade to cold-resistant. Contact us to discuss the best plasticizer solution for your needs, cost, and performance balance.
