Half a century of automotive glass boasting the top share <History story that walked with the car> The car has evolved

I asked Asahi Glass AGC Automotive

Glass is an indispensable item as a part of the car, rather than being inseparable.

This automotive glass also evolved with the car, and new technologies have been introduced one after another.

This time, let's explore the roots and try to trace the latest situation of glass for automobiles.

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Asahi Glass [now AGC after changing the company name in 2018], which boasts the top 30% share in the new vehicle installation glass market in the world.

It was in 1956 that Asahi Glass worked on automotive glass in earnest, and the year after the first Toyota Crown, the first domestically produced car, came into the market.

Although it has almost the same history as a domestic car, it goes back even further in terms of the production of glass itself, and in 1909 [Meiji 42], it began producing flat glass for the first time in Japan [Asahi Glass was founded in 1907].

In 1983, he began to manufacture tempered glass and laminated glass as early as possible, which means that he had a high level of technical skill before the war.

Asahi Glass Head Office 40th year of Meiji
Asahi Glass was founded in Amagasaki City, Hyogo Prefecture in 1907 to manufacture flat glass in Japan. The photo shows Asahi Glass just before its establishment. It was the dawn of the domestic flat glass industry for over 100 years.

Currently, flat glass is produced not only for automobiles but also by the "float method".

This is a technology for making flat glass by pouring evenly molten glass like "floating" on molten metal tin [tin] to make a flat plate glass. It has been put to practical use.

All the latest automotive glass of various kinds, and the base sheet glass, are made by this method.

Glass manufacturing factory Belgian hand-blown method
A state at the time when the manufacturing of window glass was started by the Belgian hand-blown method. First successful manufacture of flat glass in Japan. I made a glass tube, cut it and spread it into flat glass.

“The first condition of automobile glass is that the scenery outside the vehicle looks normal without distortion, and it is surprisingly difficult to clear the obvious.

Not only that, but I also pay attention to the distortion of the scenery reflected on the outside.
Asahi Glass AGC Automotive / New Product Planning Department Manager Hiroyuki Miyakawa says, but is there a high hurdle for glass among automobiles?
“With the rise of motorization in the 1960s, car designs have become more diverse, and the use of curved glass is increasing.

Furthermore, the angle of inclination of the windshield becomes larger, and there are designs that wrap around to the left and right, but it is not easy to secure a field of view in that state.

Bending the glass itself is not difficult, but it requires high technology to minimize distortion.

Now it's possible to check with computer simulations even before production, but it used to be quite difficult before. ''

Hiroyuki Miyagawa
Glass that you don't usually care about. Hiroyuki Miyagawa, AGC [Asahi Glass] Automotive New Product Planning Office General Manager [at the time of the interview], kindly explained the difficulty and depth of the development.

There is also a hurdle to safety standards for automobile glass, which is becoming stricter each year.

It is in 1983 that it was obligatory to attach safety glass to the windshield, and in 1969, it is obligatory to adopt partially tempered glass that can secure the driver's view even if the glass breaks in 1969. .

And in 1973, all the glass had to be safety glass, and in 1985 it was obligatory to install laminated glass on the windshield [passenger cars after March 1987 production and after September 1987 production]. Applies to trucks / buses].

As a result, safety in the event of an accident will greatly evolve.

“It's a highly demanding glass for automobiles, so development will take time.

We also have to think about equipment development for production.

Of course, we will proceed with development while exchanging opinions with automobile manufacturers, but regarding the shape and performance of glass, the role we expect will be greater.
The performance of the glass, the most orthodox is probably the "tempered glass".

Before compulsory use in 1985, sport cars and luxury cars were fitted with laminated glass as standard on the windshield, but many cars were still tempered glass.

"Tempered glass is made by heating ordinary flat glass in a furnace to 680-700 ° C, blowing air on it, and then rapidly cooling it.

By suddenly cooling, compressive stress is generated on the glass surface, and the strength itself is increased 3 to 5 times.

Also, when cracked, the stressed one will break at once, so there is a property that the entire surface cracks into fine fragments and the fracture surface does not become too sharp.
When tempered glass breaks due to accidents, etc., it becomes fine granular fragments, but the fracture surface is not sharp enough to be cut just by touching it like ordinary glass.

That characteristic also contributes to reducing damage to passengers.

Glass manufacturing float plate glass
In 1966, it began manufacturing float glazing, which produced very flat surface glass.

A manufacturing method in which molten glass is poured onto molten tin, formed into a plate, and then solidified.

On the other hand, the laminated glass is made by sandwiching a special resin interlayer [polyvinyl butyral] between two sheets of glass and crimping it, and it has the property that it does not easily penetrate flying objects and does not scatter when broken.

In addition, since it is hard to break or cut artificially, it has a high crime prevention effect, and it can be used on the side glass to improve security.

▽ Since the 1970s, various functions have been added to automobile glass, and the rear window will be equipped with not only the defrosting heat rays but also a glass antenna.

"I print metal on glass and receive radio waves, but the difficult thing is determining the pattern.

It is important how to create a pattern that can be received with good performance. For that purpose, we will continue to test in our own "anechoic chamber" [a facility that does not reflect radio waves].

Recently, it has become necessary to support not only radio but also radio waves from TVs and terrestrial digital waves, as well as radio waves from keyless systems, and that role is becoming more important.
It's a mysterious anechoic chamber that audio manufacturers and automobile manufacturers have, but I didn't know that glass manufacturers also have it.

Know-how about this glass antenna is now an essential element.

⑦ Automotive glass is the first condition to ensure the visibility of drivers and passengers without distortion and to ensure safety in the event of an emergency, but its role is diversifying.

It is also required to contribute to the improvement of aerodynamic performance in response to complex body styles, serve as an entrance for radio wave information from the outside, and prevent ultraviolet rays [UV] and infrared rays from entering to improve the efficiency of air conditioners.

On the other hand, it is necessary to increase the sound insulation performance in order to improve the quietness inside the vehicle and add value such as water repellency to secure the visibility on rainy days, and the demand for glass is increasing.

To meet various demands, Asahi Glass has commercialized many high-performance glass products for automobile glass alone.

Furthermore, it is no exaggeration to say that they have made proposals to automobile manufacturers and are now playing a part in the development of automobiles.

In addition to safety and comfort, automobile glass has expanded the scope of defense to include information and communication entrances and environmental performance.

Its role should become more and more important.

Published: Nostalgic Hero April 2009 Vol.132 [All content in this article is as at the time of publication]
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