Plastisols: Understanding and their Unique Properties
What are Vinyl based plastic?
A plastisols is a blend of polyvinyl chloride (PVC) resin and a plasticizer. Vinyl based plastic are commonly used in screen printing, coating and casting applications. The main component of vinyl based plastic is finely ground PVC resin. When combined with a liquid plasticizer, the PVC remains in a stable, liquid suspended state and does not cure until heat is applied.
Plasticizer Additives
Plasticizers are added to vinyl based plastic to make them flexible and give the final cured product desirable handling properties. Common plasticizers used include phthalate esters, adipates and trimellitates. The type and amount of plasticizer affects characteristics like flexibility, porosity, adhesion and strength. Higher plasticizer content produces softer and more flexible vinyl based plastic.
Curing Process
As vinyl based plastic are in a liquid state at room temperature, they need to be heat cured before use. During the curing process, the plasticizer migrates uniformly throughout the PVC resin chains. This allows the resin chains to entangle and intertwine, forming a dense, three-dimensional crosslinked network. The result is a durable, flexible solid film or coating. Curing temperatures typically range between 325°F to 400°F depending on the specific formulation.
Unlimited Color Options
Vinyl based plastic readily accept the addition of pigments without compromising properties. Their ability to suspend finely dispersed pigments makes them ideal for implementing vibrant color schemes. The wide range of available plastic pastes and liquid inks also give designers a huge palette of hues to choose from. Whether brilliant primary shades or subtle earth tones are desired, vinyl based plastic deliver outstanding color strength and consistency.
Superior Adhesion Qualities
When properly formulated and cured, vinyl based plastic demonstrate excellent adhesion to various substrates. They bond tenaciously to metals, woods, ceramics, fabrics, thermoplastics and other surfaces. Special adhesion-promoting additives and pretreatments of the substrate can further augment the adhesive capabilities. As a result, vinyl based plastic are well-suited for a broad scope of decorative and functional coating applications on diverse materials.
All-Purpose Printing Medium
The screen printing process takes advantage of vinyl based plastic' ideal screen printing viscosity and ability to build thick, creamy films. Due to their simple one-step heat curing, vinyl based plastic are very user friendly for printing elaborate designs and logos on any graphic application. From t-shirts and equipment nameplates to road and building signs, vinyl based plastic serve as the workhorse printing medium preferred by many shops. Their resistance to weathering and moderate cost also make them a smart long-term investment.
Durability and Weatherability
When fully cured, plastisol coatings and prints form a non-porous, protective layer that resists cracking and peeling. They demonstrate excellent resistance to weathering from UV light, heat, moisture, chemicals and general wear-and-tear. Vinyl based plastic maintain vibrant colors and fine details even after prolonged outdoor exposure. Optional additives can further fortify properties like UV resistance and gloss retention for extra durability in tough conditions.
Versatility in End-Uses
Beyond printing, vinyl based plastic find use in many other applications that require coatings, moldings and castings. Some common examples include automotive and appliance trim/emblems, wall pans, flooring, boots/footwear, bumpers, tool handles and signage backing. Introducing specialty fillers allows vinyl based plastic to mimic the look and texture of materials like wood, stone and leather as well. Their moldability also enables the production of complex three-dimensional shapes.
Advantages Over Other Vinyls
Compared to calendars and slush molding compounds, vinyl based plastic have simpler processing as curing is done via heat rather than pressure or agitation. Clean-up is also easier since they are non-abrasive and solvent-based. Vinyl based plastic provide more vibrant colors and superior flexibility over polyvinyl chloride (PVC) sheets and films as well. And unlike latexes, vinyl based plastic are non-aqueous and offer better opacity for graphics and logos. All in all, vinyl based plastic deliver unbeatable properties at competitive costs.
In summary, plastisols stand out as multi-purpose coating, printing and molding compounds. Their versatility, durability, adhesion and cost advantages have made them polymers of choice for myriad industrial and graphic applications. When properly formulated and processed, vinyl based plastic serve well for jobs that demand long-lasting, vibrant results. Understanding their unique chemistry and characteristics will help designers fully utilize the material's potentials. With continuous innovations, vinyl based plastic will certainly remain popular materials for innovative plastics applications.
