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What's this?

Here comes the final gate
guards who permit
the passage of
selected substances only.

Over its long history, Fujifilm has created a diversity of products and technologies essential for manufacturing.
"Filtration technology" that removes unnecessary elements from liquids and gases is one of the technologies passed down and improved for almost half a century.
This issue of What's this? unlocks the secret of micro filters as "impregnable" filtration films capable of reliably trapping fine particles that exceed a defined size.

Super longtime seller of more than 40 years, derived from the film formation technology fostered through the photographic film business.

Fujifilm and "filtration technology" may sound somewhat unrelated, but Fujifilm’s research into filtration technology can be traced back nearly half a century ago. Based on the technology of photographic films, Fujifilm came up with the idea of making microscopic holes in film to optimize the film material and create a better film. Completed in this way, through trial and error, was "AstroPore", a micro filter having numerous micro pores. AstroPore is a super longtime seller that, with improvements from time to time since its launch in 1969, has been in production for more than 40 years. Owing to its superior quality, AstroPore has received strong reviews from many customers, firmly supporting Fujifilm’s growth until today.

The pore size gradually becomes smaller inside the thin sheet. The asymmetric structure catches particles.

Now, let's see the features of micro filters. Generally, micro filters can be classified into two types depending on their trapping mechanism and structure: "nominal (filtration) type" and "absolute (filtration) type". The "nominal type" has a structure in which fibers are randomly tangled with each other. On the other hand, the "absolute type" typically has numerous micro-sized pores inside a synthetic-resin film or membrane, which is suitable for "trapping larger particles than a defined size unfailingly".

Please see here for more details about Fujifilm’s micro filters.

Nominal type
Absolute type

Asymmetric structure of Fujifilm AstroPore micro filter


We can enjoy draft beer today,
thanks to the micro filter.

From "coarse" to "dense", this unique asymmetric structure was created by sophisticated processing technology for making micro-sized pores. And, even more remarkably, Fujifilm has a superior technique for flexibly controlling the pore sizes while maintaining the asymmetric structure. This realizes diverse pore-size lineups and enables customers to select optimum micro filters that are fit for their purpose and use. Today, Fujifilm’s micro filters are used at manufacturing sites of a wide variety of industries, including to remove yeast and bacteria from brewery processes (beer, wine and Japanese sake), remove contaminants from cleaning liquids used in washing processes for liquid crystal panels and semiconductors, and many more.

Among those applications, one of the major contributions of Fujifilm’s micro filters has been their support for beer production in Japan. In typical brewing practices of the past, beer used to be heat-treated to prevent quality deterioration caused by living yeasts. In 1960s, however, breweries began to adopt micro filters for the filtration process of beer. This evolution in filtration technology made a considerable impact on beer production, enabling breweries to remove yeasts by filtration instead of heat treatment, consequently giving birth to "draft beer". Since then, in step with the popularization of draft beer, micro filters became more common as one of the essential items for brewing draft beer. In particular, Fujifilm’s micro filters have been highly recognized for their quality and adopted by major beer breweries in Japan, holding a top-class market share today. So, in a certain sense, micro filters are the final gate guards protecting the safety and good taste of Japanese draft beer.
Fujifilm will continue earnest efforts in marketing and research & development to provide the value of micro filters to even more customers all over the world.

Please see here for more details of how Fujifilm’s micro filters are utilized at breweries making draft beer.

Fujifilm AstroPore micro filter

Article published in February 2017