Cleansui specific hollow-fiber membranes

In the 1970s, a factory of Mitsubishi Rayon (now Mitsubishi Chemical) that developed fibers for filtering water and blood encountered a problem related to the opaque polypropylene fibers produced. A researcher from this company studied the fibers under a microscope and observed numerous pores on the walls of straw-like hollow fibers. The researcher improved the process, and succeeded in developing polypropylene “hollow-fiber membrane filters.” Since then, hollow-fiber membrane filters have been used in wastewater treatment and medical care. Interestingly, they were used to make the first artificial lung device in 1978.

1974 success in developing hollow-fiber membranes.

A researcher investigated a phenomenon occurred in a factory under a microscope, wherein a prepared polypropylene material was opaque, and where numerous pores were found on the wall surface of straw-like hollow fibers. The researcher was curious on the potential application of this porous hollow fibers in membrane filters; thus, the researcher conducted research on the fibers. In 1974, the researcher succeeded in developing a hollow-fiber membrane filter, which became the foundation of our products.

There are uniform pores on the wall surfaces of straw-like hollow fibers (left). These hollow fibers can effectively filter contaminants, including unwanted bacteria.

Development of the world’s first hollow-fiber membrane-based artificial lung device (1978).

From the discovery of opaque hollow fibers and development of hollow-fiber membrane filters, Mitsubishi Rayon proposed the application of these filters to various industries. These included wastewater treatment and medical care, where the highest levels of functionality and safety are required. In collaboration with a medical equipment manufacturer, Mitsubishi Rayon developed the first hollow-fiber membrane-based artificial lung device, in 1978. Thereafter, the production of polyethylene hollow-fiber membranes without using organic solvents was developed. Eventually, we branched out to the business of medical water treatment, including full scale dialyzers and hand wash stations.

The artificial lung was successfully developed and commercialized in 1978 and 1982, respectively.

About Cleansui

About the hollow-fiber membrane

The birth of the Cleansui.

In 1983, the incident of drinking water poisoning of the Mitsubishi Rayon president on a business trip in Mexico led to the development of hollow-fiber membrane filter a portable water purifier “Mashimizu” in which “hollow-fiber membrane filter” is mounted. This opened the door to the launch of innovative household water-purifying systems. Indeed, in the following year, the household countertop water purifiers “Cleansui S” and “Cleansui D” were introduced to the market. In 1989, Cleansui Petit that is the first faucet-mounted water purifier in our Cleansui series achieved explosive sales. This stimulated the growth and expansion of our lineup.

Award-winning designs

The aesthetic designs of the Cleansui products have attracted significant attention, and have bagged several awards in domestic (Japan) and global design competitions. The brand received “the Red Dot Award,” which is one of the largest design award in the world for three consecutive years (2018–2020). In 2018, we received the Red Dot Award in Product Design for the Cleansui Shigaraki JP100-C water purifier. This purifier was the first product from the project “Cleansui Knows Japanese Crafts,” a collaboration with skilled craftsmen who followed Japanese traditions. In the following year of 2019, we received the Red Dot Award in Brands & Communication Design for our corporate identity (CI) of “Cleansui,” which was produced by graphic designer Taku Satoh in 2009. In 2020, we received our second Red Dot Award in Product Design for the faucet-mounted water filter “Cleansui CSP901,” which was designed by product designer Fumie Shibata.

Cleansui should be the preferred brand by customers.

There are several reasons for selecting Cleansui products over other water purifiers in the market. First, Cleansui high-performance water purifiers with innovative hollow-fiber membrane filter technology can absolutely remove the 17 and 2 substances designated by the JIS S 3201 (Testing methods for household water purifiers) and Japan Water Purifier Association, respectively. Meanwhile, they selectively retain the beneficial minerals in tap water. Then, their sophisticated yet user-friendly design is attractive. Next, the low cost-performance ratio of the faucet-mounted purifier (one cartridge) that produces purified water equivalent to 450 2-liter plastic bottles of water has been unrivaled. Finally, we have a substantial after-sales support department that effectively facilitates the periodic delivery of replacement cartridges and customer care service to guide customers on the proper and carefree use of our products.