Sunshine is vital for life on our planet as without it, the planet would be a cold and dark place.  Coming from that huge ball of fire 150 million kms away, sunshine provides warmth, kills germs and illuminates the world around us for half the day. Yet the heat from the infra-red (IR) rays in sunshine as well as the effects of ultraviolet (UV) rays can damage the cells and in cases of over-exposure, cause skin cancer.

Motorists may imagine that they are protected from excessive exposure to sunlight by being inside a car. Yet this is not really the case because a great deal of sunlight comes through the glass windows, especially the windscreen which, in modern cars, is at a shallow angle. Thus even while driving around town during the day, the skin will be exposed to sunshine for some time. So apart from the discomfort of high temperatures inside the cabin, you are also running the risk of having cancer in the long-term! To reduce cabin temperatures to a comfortable level, air-conditioners are now a common fitment.

The early cars had glass for the windows which was clear and it was only in the 1960s that tinted glass started to be available.

Old cars (those before the 1960s) had plain clear glass which let in 100% of sunshine but then manufacturers began to tint the glass. Tinting glass was nothing new actually, as the process started in the medieval times (5th to 15th centuries) when glass was coloured using metallic oxide powder. There were no cars then so the glass was used for palaces and religious buildings, which you still see today.

From the 1960s onwards, many cars came with glass that had a light tint to reduce the reduce amount of sunshine entering the cabin. The level of tinting was not very high as visibility at night had also to be considered but it did at least make things a little bit more comfortable.

However, while it reduces transmitted light, the tinted glass actually did little to reduce the transmission of the more harmful IR and UV rays. To offer better protection from sunshine, dark tinted film was used and an aftermarket industry was born to provide it. Initially, the approach was just to add a dark layer on the glass but darker does not necessarily mean better. This is because the invisible IR/UV rays are at different wavelengths in the light spectrum and can still be transmitted through a dark tinted film. So darkening the glass for better comfort was not necessarily true and the main benefit was privacy.

There were no specific laws in earlier years regarding the level of tinting so motorists could add on whatever they wanted. Today, there are laws on this aspect and in Malaysia, the current regulations have the following conditions: windscreen – 70% of light to pass through (Visible Light Transmission or VLT); front side windows – 50%; rear side windows and rear glass – 30%. The law is mainly meant to enable law enforcement officers to be able to look into the car more easily.

Current Malaysian regulations for Visible Light Transmission on motor vehicle glass

There are provisions for some vehicles to have tinting lower than required VLT levels. These are for motorists who have a certified medical condition relating to exposure to sunlight, royalty and law enforcement vehicles. The Transport Minister has also mentioned that others with tinting not meeting regulations may apply for approval and if allowed, they will be charged a fee. This is probably to address the long-standing issue of some imported models with original tinted glass that is allowed in other countries which have different regulations.

The only exception is on the top of the windscreen where a dark tinted band can be applied for reducing sky glare. However, the height of this band, which is not subject to any minimum light transmission level, must not be more than 20% of the height of the windscreen.

In 1966, 3M (a company well known for its adhesive and laminate products) was the first company to receive a patent for ‘sun control window film’ and it made a breakthrough in automotive tinting film when it developed technology that added metallic coatings to the film. These coatings could block much of the harmful rays without making the film darker. The metallised film technology inserts a layer that is about 1/100th the thickness of human hair but it can prevent cancer-causing UV rays from reaching into the cabin.

Apart from the better protection for your skin, there is also less deterioration of the areas such as the dashboard which fade or crack after prolonged exposure to sunlight. This is because, in addition to the very high temperatures, UV rays can break the chemical bonds of a polymer, and much of a dashboard is made from this material.

The reduction of IR rays is also significant, which not only reduced heat transmission but also reduces the workload of the air-conditioning system, in turn, helping to reduce fuel consumption.

In more recent times, the use of devices to electronically pay toll posed a new problem for the film manufacturers. Because many of these devices use IR beams and the film blocked IR rays, the signals could not go through to the receiver at the toll plaza. As a result, owners had to cut a hole in the film to expose the tag. However, this issue has also been overcome with new technology.

Since 1966, 3M has continued to advance the technology of its tinting films and its latest Crystalline AutoFilm has a proprietary multi-layer optical film that combines over 200 layers of nano-technology. The technology prevents 99.9% of UV rays from entering the cabin which would be comparable to using protective sunblock cream to a level of SPF 1000. ‘SPF’ stands for Sun Protection Factor and is a measure of protection from UV exposure, and 1000 is certainly much higher than what the usual creams and sprays provide.

The Crystalline film also prevents 97% of IR rays and 60% of solar heat from entering the cabin, making journeys more comfortable on the hottest days. A side benefit is also the reduced glare, which means less fatigue on the eyes. Amazingly, the Crystalline Series rejects more heat than many dark films.

3M was also the first to offer a tough film for cars in 1969, a response to the growing number of terrorist attacks on vehicles. It was able to hold the broken glass in place instead of falling apart. As time went on and new technology was developed, the security film gained more useful properties such as providing additional protection against being smashed. This has become more appreciated by motorists, especially in Malaysia, where there was a high incidence of smash-and-grab thefts.

3M has combined the security properties with its film nano-technology in the Scotchshield Crystalline series. For a little bit more money, motorists can thus have not only protection from the harmful rays of the sun as well as from snatch thefts.

3M is not the only company that offers metallised films but its proprietary technology and high standards of manufacturing ensure that over many years of usage, corrosion within the film will not occur. When corrosion occurs, it is not only unsightly but can also compromise the protective properties. Furthermore, with its long experience in adhesives, the film will also not peel off the glass after a while. For peace of mind, 3M AutoFilm products are backed by one of the most comprehensive warranties when installed by professional 3M Authorized Dealers.

[Chips Yap]

 

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