Guest post by Rowena Fletcher-Wood
Open your eyes and take a closer look: sometimes that’s all it takes to realise a new invention has been with you all along, stuck, perhaps, to the cuffs of your trousers and the fur of your pointer. Like the burrs of the burdock, evolved to stick to the fur of animals, transporting the seeds far and wide to fall on new ground.
Velcro hooks
Image by Alexander Klink – CC-BY
Swiss amateur mountaineer Georges de Mestral had been hunting in the French Alps one summer evening in 1948, when exactly this occurred. He had obviously encountered burrs before, but for the first time his mind connected an observation (the sticky burrs) and an application (fashion) – it was a scientific portmanteau or ‘blend’ of two ideas, contracting their meanings into a single new commodity: Velcro. The name is a portmanteau too, a combination of the French words velour and crochet: the soft fabric side and the hooked. De Mestral had stumbled upon a new way of fixing clothing, but was it such an accident? Louis Pasteur, scientist and inventor of the Pasteurisation process, famously said ‘in the fields of observation, chance favours only the prepared mind.’ He had a point.
An engineer by trade, de Mestral immediately stuck the intriguing burrs beneath a microscope to observe how they functioned, noting that they consisted of miniature hooks that tangled readily with hairy loops. But to work in fashion, these hooks needed other special properties: they needed the flexibility and longevity that would allow them to straighten out when pulled away from the loopy surface and bounce back into shape upon release, eager to hook again.
Undaunted by their smallness, de Mestral set about constructing the tiny hooks that demonstrated his principle from cotton with the help of a weaver. He created a functioning velcro, but unfortunately the cotton hooks wore out after just a few detachments, bending permanently and losing their ‘stickiness’. But it was the loops or velour which really caused him trouble: velour, itself a cotton-based velvet-like material, is not particularly sticky, and the connection was weak. His colleagues laughed at him, but de Mestral persisted – for nearly eight years.
Then came the invention of nylon.
De Mestral jumped upon it and stuck to it like velcro. He rapidly discovered by trial and error that sewing the hooks under infra-red light make them tough and increased their durability. Furthermore, nylon is inert to rot, mould, or decomposition in the lifetime of a product – de Mestral had found his fabric and patented the invention in 1955 before moving on to creating a loom that could weave velcro hooks and trim them smoothly, initiating mass production.
Today, not all velcro is equal. ‘Industrial velcro’ is made of woven steel wire and used in high temperature applications. Space shuttles use Teflon-looped polyester-hooked velcro fused into glasses. It’s also used to stick tail light covers to cars. Most domestic velcro is made of nylon or polyester, each with benefits and drawbacks. Nylon lasts longer, with a half-life of 10,000 attaching and detaching cycles – equivalent to 27 years of opening and closing once a day. Polyester velcro, meanwhile, only lasts 3,500 cycles, but it is also less sensitive to decomposition under heat, moisture and ultraviolet light.
It’s now become commonplace, but velcro According to Anthony Rubino, Jr’s book Why didn’t I think of that, a 2 inch square unit of velcro can actually take the weight of a 79.4 kg person (is this something to try at home?)
Eventually, many cycles will compromise the velcro, but that’s okay: the internet sports several methods for revitalising it, including rubbing it with a toothbrush, scratching it with a pin, or melting and trimming off the loops. Whilst this may be effective if dirt and debris have depleted your velcro quality, it’s not so good when eventual uncurling of the loops is at fault. You may find this happens faster with some products than others: not all ‘velcro’ today is really velcro. After the patent ran out in 1978, the market became flooded with cheap imitations, some of which have been reported to only last a few months.
Despite what Star Trek says, velcro was not invented by the Vulcans, just an observer with a well prepared mind.
