A back to white reality: A unique treatment to remove the stigma of pinking in Pvc-u

Pinking is an unfortunate but widespread occurrence in PVC-U products, resulting in a characteristic pink colour, which develops on the surface of the material. This phenomenon is generally believed to be due to a combination of specific titanium dioxide pigment properties with generic lead-based stabilisers used by some extrusion manufacturers for many years. The majority of extruders affected changed to non-pinking formulations in the late 1990s but only after many thousands of tons of PVC-U with the potential to pink had been installed.

The response to pinking from suppliers has largely been very secretive but provisions in the balance sheets of public listed companies have hinted at the extent of the problem.

Pinking mechanism

For pinking to occur, both indirect sunlight and surface moisture are required. Pinking occurs predominantly on the North-facing elevation of properties (indirect sunlight side). In areas of high moisture such as coastal and hilly areas, PVC-U installed on the South-facing elevation can also be affected. It has been found that pinking requires about 1.5 to 2 years (inductive period) before it starts to become apparent to the householder.

The compound producing the pink effect is a chemical species of lead, which is produced by a reaction between the lead stabiliser, water, UV radiation and the titanium dioxide pigment. The lead compound producing the pinking effect is located in a thin layer near the surface of the PVC-U. By removing the PVC-U from the wet environment, pinking can be reversed back to white. Exposure to direct sunlight can speed up the reversal and if placed back into the wet environment, pinking will re-occur but without the 1.5 to 2 year inductive period being required.

One-stage treatment

A unique solution called Whitin is available from Nottingham based Silexine PVC-U Solutions, a company that specialises in surface remedial treatments for problems occurring on PVC-U frames.

Whitin scientifically reverses the effects of the discoloration and protects the surface against subsequent pinking

Applied as a one-stage treatment, Whitin scientifically reverses the effects of the discoloration and protects the surface against subsequent pinking. When the pinked PVC-U surface is treated with Whitin, a formulation of additives is carried into the PVC-U surface and then locked into the resin matrix. These reverse the lead chemistry, protect against the ingress of moisture, and provide an additional stabilisation and UV absorption function.

Cost effective

Silexine’s Sales & Marketing Director, Sarah Gibson says that ‘Whitin is less expensive than other remedial alternatives. Weather-tolerant, the treatment can be applied at any time of year. Consisting of chemicals no more hazardous than those available in the DIY market means that Whitin is safer to use and is environmentally friendly’.

Silexine has a network of approved applicators with a geographical coverage of the UK and Eire ready to provide a cost-effective solution to pinking, all having been fully trained and registered in the application of Whitin.

Treatments carried out by Silexine’s network of approved applicators carry a five-year guarantee on the product and application process issued directly to the householder.

While greater openness about pinking is unlikely for obvious reasons, the straightforward Whitin reversal treatment from Silexine promises to remove the stigma.