Croda’s Priplast is a range of polyester polyols offers based on our dimer technology; they incorporate a flexible element to the resin, making it more suitable for e.g. low temperature applications, stressed parts, durable product, while their hydrocarbon character imparts excellent water repellency and hydrolytic resistance to the material.
The Priplast technology, when built into the polyurethane by reacting with isocyanates, offers unique benefits to polyurethane adhesives and coatings, such as:
- Durability: a unique combination of thermo-oxidative and hydrolysis resistance
- Moisture repellency of the final formulation, also achieved for PU dispersions
- Adhesion to a wide range of substrates, including low-polarity plastics
- Good chemical resistance
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Bio-based polyurethane adhesive formulations
To meet the growing market demand for performance and bio-based PU formulations we have developed the 100% bio-based polyols Priplast 3238 and Priplast 3294. These Priplast grades also offer the unique benefits to polyurethane adhesives as mentioned above and contribute to sustainable product innovation, meeting the performance criteria of your customers.
The demand for adhesion to non-polar, low energy substrates such as polyolefins and rubbers is becoming more important as the use of plastic parts becomes more prevalent in many end applications. The excellent adhesion to these substrates provides flexibility to formulate for a large variety of substrates. This opens the possibility of formulating a single coating system which works well on multiple substrates, or an adhesive capable of bonding very different substrates together.
Priplast in polyurethane dispersions
Water-based polyurethane dispersions (PUDs) are nowadays a rapidly growing segment due to their technological advances and environmentally friendly profile.
However, existing polyurethane dispersion technologies still have some drawbacks such as the hydrolytic stability of the dispersion and the chemical and UV resistance of the coating.
Priplast C36 dimer based polyester polyols provide the solution to these challenges. The branched structure offers flexibility to the resin and the hydrocarbon character imparts water repellency. Priplast enables the market to formulate environmentally friendly, high performance polyurethane dispersions with improved performance.
The Priplast product range offers the following benefits to polyurethane dispersions:
- Good storage stability
- Process drying time reduction
- Chemical resistance to attack by moisture, alkali or acid
- Adhesion improvement on various substrates
- Excellent outdoor stability
- Good storage stability
- Hydrolytic stability is a shortcoming of most conventional polyester polyols (e.g. adipate esters) used in the polyurethane industry.
The Priplast polyester polyol hydrocarbon nature gives a very hydrophobic environment with a low level of vulnerable ester bonds. Therefore, the Priplast polyol provides excellent hydrolytic stability to a PUD, whilst maintaining its properties over time.
Priplast in COPA
Copolyamide elastomers are high-end block copolymers, ranging from soft to semi-rigid products with good impact strength, low temperature flexibility and chemical resistance. They consist of polyamide hard segments (typically Nylon 12) and soft segments which usually are polyether such as PTMEG.
In conventional COPA elastomers, ether linkages render the material susceptible to degradation by UV and thermo-oxidation (heat), limiting application development. Traditional polyester soft segments (e.g. adipates) to solve these shortcomings result in poor hydrolysis resistance and segment randomization (resulting in a loss of thermal properties).
These shortcomings can be overcome by using special dimer based Priplast polyester soft properties such as a high melting point and oil resistance.
Priplast bio-based polyester polyols offer the following unique properties:
- Special phase separated morphology
- Good mechanical properties and impact strength
- Lifetime extension:
- resistance to heat, oxidation, UV
- resistance to hydrolysis
- chemical resistance to hydrocarbons such as oil and grease
- Wide application window:
- Very low Tg (~ - 50ºC)
- High melting point (hard segment dependent)
- High renewable content, up to 100%
Priplast is used at 5-15% to maintain hardness of an engineering plastic, or at 20-45% in copolyamide elastomers. Priplast modification of COPA elastomers allows application in heavy-duty sports and in automotive areas such as cables and tubes.
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