Glass wool in East Asia ~China, Taiwan and Korea~

Glass wool, a leading sound-absorbing material, is produced all over the world.

Sonora Technology is a Japanese company and  we procure the glass wool also in Japan.

In this article, I will describe the characteristics and differences between Asian (Chinese, Taiwanese and Korean) glass wool and made-in-Japan glass wool.

* based on the author’s experience, which means not targeting all the glass-wool manufacturers.

Chinese glass wool

Chinese glass wool has the following properties:

• thick fibers
• low binder content
• low sound absorbency (no sound absorption coefficient published by manufacturers)
• easy to lose its shape
• large dimensional tolerance
• expensive

There are a huge number of glass-wool manufacturers in China, many of which are engaged in primary and secondary processing at the same time. When I visited the glass-wool manufacturer A, a mass production of glass wool has been done in a very large factory.

The glass fibers consisting of glass wool are thick and when cut manually with a cutter, the cutter blade gets caught and the cut surface is uneven. Thick and hard fibers cause the cutter blade to chipped.

The reason for the thick fibers is their lack of technology to produce fine fibers. According to the manufacturer I visited, their technology was originally provided by a Japanese glass-wool manufacturer. However, it has not been developed since then.

In addition, the payment was made in advance when purchasing glass wool, and the arrival date and time of the truck for transport was unclear.
Then we suddenly received a call saying “the truck will be supposed to arrive at 3 a.m. tomorrow morning, so unload products there.” So, we arranged for four workers to unload them at 3 a.m.

The glass wool was simply wrapped in plastic packaging, but most of the plastic was torn, exposing the contents. Furthermore, the dimensional accuracy of the glass wool was low, with a tolerance of around plus or minus 10 mm.

I don’t believe that all the Chinese glass-wool manufacturers are the same like this, but here’s what is happening in the reality. Finally, I have decided never to deal with them again.

Taiwanese glass wool

Taiwanese glass wool has the following properties:

• wide variety of densities.
• fine fibers (made in Japan).
• dimensional accuracy not bad
• many binders
• combustible
• inexpensive

I visited the glass-wool manufacturer H in Taiwan. The company H imported glass fibers from Japan and performed a press molding process for them in their own factory in Taiwan.

I visited their factory based on advance information that their materials were of a level that could pass the non-combustibility test certified by the Japanese Minister of Land, Infrastructure, Transport and Tourism.

According to the company H, since its materials have already passed the strict non-combustibility test in Taiwan at or above the equivalent level of Japanese one, those would also be able to pass the Japanese test without any problems.

Its material was high-density glass-wool board. Since it had fine fibers with a density of 150K and high dimensional accuracy, I brought it to Japan and a non-combustibility test was undergone.

However, it did not meet the test conditions in Japan. The reason for this is considered to be that the rate of binder content was too high, resulting in a higher exothermic temperature. Therefore, it was unfortunately rejected.

Korean glass wool

Korean glass wool has the following properties:

• thick fibers
• large dimensional tolerances
• non-uniform density
• contamination in glass wool
• cost: initially inexpensive, however, much more expensive later due to price hikes

Around 2010, a supply shortage of glass wool occurred in Japan and they vanished away from the market for a certain period of time. At that time, Japanese companies managed to import the glass wool from abroad.

As our shortage of glass wool in stock caused difficulty to handle projects, Sonora Technology also tried to import the glass wool from Korean glass-wool manufacturers K and B. However, we found that dust was already mixed in when having cut the glass wool. So, we had no choice but to dispose of them as they were not usable at all.

Later on, the prices of glass wool from manufacturers K and B were jacked up.

* We assume they took advantage of the supply shortage in Japan.

Japanese glass wool

Japanese glass wool is manufactured by the following three major manufacturers.

• Asahi Fiber Glass
• Mag-Isover
• Paramount Glass

The glass wool is processed into boards or rolls at these manufacturers, and it is sent to a secondary processing company when secondary processing is required.

Compared to the above-mentioned Asian glass wool, Japanese glass wool is by far the best quality and has a wide range of solid evidence.

As you can see, even within the same Asian region, there are significant differences in even a single material between countries. From foreigners’ point of view, all of Asian countries may look the same -we often hear that- however, even though Asian countries may look similar, cultures are very different from each other. The same applies to business.

In a country where proper materials cannot be manufactured cannot construct a full-fledged anechoic chamber -they might lie and say they can though…

If you are considering purchasing an anechoic chamber, please evaluate and compare each company with a critical eye.

There are excellent anechoic-chamber manufacturers in the world, while not-so-good ones as well. So, we’d like to compete with excellent nominees.

• Excellent proven anechoic-chamber manufacturers
• Company F in Krumbach, GERMANY
• Company I in Hampshire, UK
• Company E in Massachusetts, USA

AND

• Sonora Technology Co., Ltd. in Tokyo, JAPAN