The word ‘kapok’ refers to both the tree and the fibre it produces, which is also known as ‘silk cotton’. Native to Central America, it is widely spread in rainforests around the world and is grown commercially in Java, Thailand and other countries. The hair-like fibres that surround kapok leaves are best used for stuffing, however use has decreased following the rise of synthetic fibres.
The kapok fibre has a hollow core, meaning it is extremely lightweight – up to 8 times lighter than cotton – as well as equipping it with insulating properties. The fibre is naturally encased in a water-resistant wax, making it incredibly buoyant. Kapok can support up to 30 times its weight in water and for this reason, has been used for life jackets in the past. The waxy coating also gives the fibre a ‘slippery’ quality, making its shape flexible, in a pillow for example. It is highly durable, bouncing quickly back to shape and, unlike polyester, it is biodegradable and hypoallergenic. Kapok can be reused again and again without decaying. A fully grown plantation tree yields around 15kg of fibre a year, and is also a good source of timber, which it is predominately used for.
Kapok fibres alone are not suitable for spinning into yarn, as they are too smooth, slippery and brittle. Additionally, the kapok harvest is labour intensive as the fibre rich pods grow high up in rainforest trees, even when harvested from the ground they must be beaten to encourage fibres to fall to the bottom of their container. Harvesting kapok is also irritant, since the fibres are designed to disperse seeds in the wind; it is advisable to wear a mask to prevent seeds from irritating the lungs. Kapok’s air-trapping capacity makes it highly insulating but also very flammable, though technologies are being developed to make kapok more fire resistant.
Kapok is a supportive and insulating stuffing with hypoallergenic qualities well suited to bedding. Its uses can be expanded to other textiles when blended with other fibres, such as organic cotton.