When PVC is heated to 170~180°C, chlorine and hydrogen in the molecules are eliminated and release of hydrogen chloride becomes evident. Once such decomposition starts, unstable structures are formed in the molecule, which further accelerate HCl elimination and decomposition. As PVC is heated to soften during the extrusion or moulding process, prevention of hydrogen chloride elimination due to heat and subsequent decomposition is required. The stabiliser prevents such initial elimination of hydrogen chloride from PVC.
Therefore, use of stabilisers (metal compounds) is essential to prevent the chain reaction of decomposition. They can also impart to the PVC enhanced resistance to daylight, weathering and heat ageing and have an important influence on the physical properties and the cost of a formulation.
The main heat stabilisers in a formulation are usually combined with co-stabilisers which are organic materials such as polyols or epoxidised esters: they provide an additive synergistic effect, especially in the case of some forms of heat stabiliser, an enhancement of overall stabilizer performance.
Blend-OX One Pack Systems
Consisting of a multi-component blend of additives 100% active, tailored from a wide range of additive products to meet customers’ needs. Homogeneous and highly accurate in composition, Blend-Ox OPS help to optimize our customers’ compounding processes, improving dosing accuracy, minimizing dust, increasing process reliability and reducing quality control & logistics costs.
Other Grades
The choice of heat stabiliser depends on of factors including the technical requirements of the PVC product, regulatory and cost.
- Calcium Zinc Stabilizer (CaZn)
- Tri Basic Lead Sulphate (TBLS)
- Dibasic LeadStearate( DBLS)
- Dibasic Lead Phosphite (DBLP)
- Lead Stearate (LS)
protectors- Antioxidants, twinary Blends & Thioesters
Phenolic antioxidants (AOs), also known as primary antioxidants, are highly effective, non-discoloring stabilizers for organic substrates that are prone to oxidation, e.g., plastics, synthetic fibers, elastomers and waxes. act as free radical scavengers, and are primarily used to protect the finished product.
Phosphite antioxidants, also known as secondary antioxidants, act as peroxide decomposers, protecting the polymer and ensuring color retention of oxidation-prone organic polymers, especially during processing.
Thioester antioxidants decompose and neutralize hydroperoxides formed through polymer oxidation. Thioesters are used to provide heat aging protection and to preserve color.
Aminic antioxidants help to preserve physical and surface properties, including color, and scorch and heat resistance.
Twin blends are a combination of a primary (phenolic) antioxidant and a secondary (phosphite) antioxidant for optimum stabilization during processing and service life.
Stabilizer Solutions
Our range of innovative stabilizer solves a number of the key issues our customers face during processing, conversion and end-use life cycles.
Hindered Amine Light Stabilizers (HALS)
- Hindered amine light stabilizers (HALS) protect polymers from degradation due to UV exposure by neutralizing them. HALS regenerate during neutralization and continue to provide protection throughout the life of the end product. They also act as primary antioxidants with low color generation.Monomeric HALS provide effective surface protection, while polymeric HALS protect the core of the material.
- UV absorbers provide protection by absorbing heat from UV radiation and, through a reversible chemical rearrangement, dissipate the energy as heat. HALS and UVAs can be used together to achieve optimum UV protection.
- Hydroxybenzoates are free radical scavengers that in some cases also act as UV absorbers. Hydroxybenzoates can perform synergistically with HALS to provide superior performance