Williams is using most of the sale proceeds to return pounds 300m of capital to shareholders representing 8 per cent of its equity. The group, which is now focused on fire protection and security products, also announced plans for the flotation next year of its Portuguese paints business Robbialac which is expected to raise another pounds 100m.
ICI said it would integrate the newly-acquired business with its paints division, which includes the Dulux brand, to strengthen its presence in the European decorative products market.
The business being bought by ICI employs 1,250 people and made profits of pounds 34m on a turnover of pounds 185m in 1997. It has factories in the UK, Austria, Germany, the Netherlands and Italy and last year two-thirds of sales were outside the UK.
Cuprinol is one of the DIY market's biggest selling wood preservatives while the rust treatment Hammerite is sold right around the world.
The sale brings proceeds from Williams' disposal programme to pounds 500m. Earlier this month it agreed to sell its US home products business, NuTone, for pounds 150m and 15 months ago it disposed of its other home and DIY brands, including Rawlplug.Reuse content