NITTAI Co., Ltd.

Hydrotect tile

TOTO Hydrotect

Benefits of Hydrotect tile (1)Air cleaning effect

The oxidation power of photocatalysis cleans air polluted by exhaust fumes

The toxic substances in the air that negatively affect people are dissolved and cleaned by the reactive oxygen generated from photocatalysis using the clean energy of sunlight.

Constructing buildings using Hydrotect tiles is like planting trees in the city

Plants act to clean the air and absorb and eliminate air pollutants like nitrogen oxide. Hydrotect also eliminates nitrogen oxide at the outer walls of buildings to the same level as these plants. Hydrotect tile has this ability.
An area of 1000 m2 is equivalent to 70 poplar trees.

Hydrotect tile 1000 m2 Poplar 70 trees
Reference: in the case of a single residence, if 200 m2 of tiles is affixed to the outer wall, this is equivalent to 14 poplar trees.(From TOTO test results)
air cleaning power of hydrotect tiles
*Estimate based on TOTO test results. Results for building exteriors as of January 2007.

Cleaning mechanism

  • Nitrogen oxide is a toxic substance that causes photochemical smog, acid rain, and other air pollution.(Nitrogen oxide includes nitric monoxide (NO) and nitrogen dioxide (NO2))
    Nitrogen oxide is a toxic substance that causes photochemical smog, acid rain, and other air pollution.
    (Nitrogen oxide includes nitric monoxide (NO) and nitrogen dioxide (NO2))
  • The nitrogen oxide in the air is adsorbed by the surface of Hydrotect tiles.
    The nitrogen oxide in the air is adsorbed by the surface of Hydrotect tiles.
  • When the surface of the tile is hit by sunlight, nitrogen oxide is oxidized and then sticks to the outer wall as NO3- (nitrate ion).
    When the surface of the tile is hit by sunlight, nitrogen oxide is oxidized and then sticks to the outer wall as NO3- (nitrate ion).
  • The solid NO3- (nitrate ion) combines with rainfall or other water to form HNO3 (nitric acid), which is washed away.
    The solid NO3- (nitrate ion) combines with rainfall or other water to form HNO3 (nitric acid), which is washed away.
  • The amount of HNO3 (nitric acid) is extremely small, and it becomes plant fertilizer in soil.
    The amount of HNO3 (nitric acid) is extremely small, and it becomes plant fertilizer in soil.

Benefits of Hydrotect tile (2)Self-cleaning effect

The actions of photocatalysis make the surface stain-resistant and easy-to-clean

Because the power of light and rain keep buildings constantly clean, this economical tile retains its beauty for a long time and requires little maintenance.Furthermore, detergent and water for maintenance can be reduced, which contributes to environmental conservation.

Testing the self-cleaning effect

We applied stains to the tile surface, poured water like rain, and then looked at the results.

Hydrotect tile
self-cleaning effect of hydrotect tiles
Standard tile
self-cleaning effect of standard tile

*Results of testing by TOTO. Effects may differ by conditions.

Self-cleaning mechanism

  • Water film restricts adsorption
    The water film generated by the hydrophilic layer restricts the adsorption of dirt and dust from static electricity.
  • reactive oxygen dissolves stains
    Reactive oxygen dissolves stains on the surface. Weakens adhesion.
  • Rinsing by rain
    Rainwater penetrates under the stain, and then the stain floats away through washing.

Bringing out the Hydrotect effects

Building an outer wall that stays beautiful forever

Hydrotect tiles (for exteriors) keep tile outer walls beautiful forever through the self-cleaning effects of photocatalysis. To best bring out the self-cleaning effects of these tiles and keep exteriors beautiful longer, sealing material and adjustment (detailing) must be considered in the design stages of the building.

Select outer wall material (Hydrotect tile) resistant to stainsSelect sealing material considering stainsAdjust the tiles to minimize stains
  • Select outer wall material resistant to stains

    Select Hydrotect tile for the outer wall material resistant to stains.

    Comparison two years after construction

  • Select sealing material considering stains

    Do not use silicone sealing material because it tends to easily stain the tiles. Use polyisobutylene sealing material.

Adjust the tiles to minimize stains

Use a drip edge or similar device to prevent stains from dirty water flowing down the wall surface.


1) Place the drip edge 30 mm or more (as far as possible) from the finished surface of the outer wall.

2) Form a convex shape at the lower part of the drip edge.

3) Use polyisobutylene or modified silicone-based sealing material, which have low staining properties, to mount the drip edge.

  • Hydrotect tile (for exteriors)

    ■ Usage precautions

    • To sufficiently exhibit the anti-staining function, sufficiently wipe stains due to glue, post-construction mortar and the filling of the joints.
    • The self-cleaning effect uses the washing action of rainwater. Be aware that the effect cannot be sufficiently exhibited in locations that do not receive rainwater. Hydrotect tile is not effective against rust, efflorescence, yellow sand, and other inorganic stains because the components cannot be dissolved by the Hydrotect tile. Furthermore, the self-cleaning effect may not be sufficiently exhibited with stains that form in a concentrated manner*, even in the case of organic stains, when the stains exceed the photocatalytic capacity.
      *Moss, algae, mold, bird and insect feces, beehives, sap, etc.
    • Avoid using silicone sealing material because it tends to stain the tiles a lot, so there may be no effect.
    • Hydrotect tile creates a stain-resistant surface. For this reason, the adhesion of PC backed-tile film is also weakened, so consult with one of our business offices when selecting the film.
    • Use a steam-curing temperature of 60 °C or less during PC pouring.
    • Wash within two days after removing the forms. If mortar waste or other material remains on the tile surface, the Hydrotect function decreases. When acid cleaning will be performed, moisten the joint sections sufficiently, and then use a hydrochloric acid aqueous solution of 1-3%. Rinse sufficiently after cleaning to ensure that no acid remains on the tile surface.
    • During cleaning, use a sponge or brush made of nylon or another comparatively soft material. Avoid tools made of a hard material, such as a metal scrubbing brush, cutter, or trowel. If the tile surface is rubbed with such an object, metal marks may remain on the surface.
    • Avoid cleaning agents that include hydrofluoric acid. The photocatalyst may penetrate the enamel layer and cause discoloration.
    • Hydrotect tile can protect its appearance through its self-cleaning effects. For that reason, stains on joint material may stand out. Therefore, we recommend using joint material of an inconspicuous color (such as gray or dark gray).
    • As with general tiles, Hydrotect tiles are subject to iridescence phenomenon. This is particularly true with dark tile. It is not possible to clean using Clinston products, which are effective for typical tile when this iridescence phenomenon occurs. Please understand this characteristic before use.

    The durability of Hydrotect tile (for exteriors) is the same as general Class 1 tile. Based on JIS measurement standards, chemical resistance, weather resistance, and wear resistance testing resulted in "No change".

  • ■ Safety of titanium oxide

    The titanium oxide (TiO2) used for Hydrotect tile was recognized as a food additive in the United States and Japan in 1968 and 1983, respectively, and is widely used in food products, lipstick, and other cosmetics. Hydrotect tile was recognized as a safe product after a primary skin irritation test*1 and acute oral toxicity test*2 by an external organization.

    * 1

    Hydrotect tile testing organization: Japan Food Research Laboratories

    Publication date of test transcript: March 30, 1995

    Test transcript publication number: TM88020114-2

    * 2

    Hydrotect tile testing organization: Japan Food Research Laboratories

    Publication date of test transcript: April 6, 1995

    Test transcript publication number: TM88020114-4

    *1 and *2 are test transcripts requested by TOTO.

    ■ Safety of reactive oxygen

    • Reactive oxygen exists in the air normally and is also created within the body normally. If a large amount of reactive oxygen is taken by the body, the body may be negatively affected.
    • Reactive oxygen generated from the photocatalysis of Hydrotect tile advances only on the tile surface (ceramic panel surface) and does not float in the air. Furthermore, the lifetime of reactive oxygen itself is extremely short and is not taken by the body.
    • Another example of reactive oxygen useful in everyday life is hydrogen peroxide solution, which is often used as a disinfectant. Hydrogen peroxide solution generates reactive oxygen on the skin surface to kill bacteria and microorganisms.

*Hydrotect tile can only be sold within Japan.

Hydrotect processing of wet molded goods

Wet molded tiles for exterior walls with Hydrotect processing are also handled as made-to-order goods.
The following two main conditions must be met for the self-cleaning function to be exhibited sufficiently.

  • Create a photocatalyst function layer uniformly on the tile surface
  • A low water-absorption tile surface that does not allow water absorption and adhesion of stains

From Condition 2

To best bring out the self-cleaning effects from Hydrotect processing on Class 2 (stoneware) wet molded tiles, which have a water absorption rate slightly higher than that of porcelain glazed tiles, a clear enamel layer is provided between the photocatalyst function layer and the tile material to prevent surface water absorption.

Stain adhesion test

The following images show a comparison of the differences of stain adhesion when dirty water was dripped forcefully under the same conditions assuming outdoor stains on wet molded tile with no Hydrotect processing (with no clear enamel), with Hydrotect processing (with no clear enamel), with no Hydrotect processing (with clear enamel), and with Hydrotect processing (with clear enamel).

The combination of clear enamel and Hydrotect processing can be expected to reduce stains on wet molded tile.
*The stain adhesion conditions differ by the conditions of the actual location.

● Hydrotect processing

Existing products that can receive HYDROTECT processing have a "Hydrotect compatible product" mark. Please understand that Hydrotect processing cannot be applied to products in stock. Hydrotect tiles are handled as made-to-order products through factory manufacturing. Shapes other than those of our existing products are also handled. Please consult one of our business offices as there are restrictions on shapes, sizes, colors, firing methods, and other factors.

● Price setting

The price of Hydrotect products differs greatly by the desired tile and quantity. For details, inquire at one of our business offices.

● Delivery

The delivery of Hydrotect products differs greatly by the desired tile and quantity. For details, inquire at one of our business offices.

Cautions

  • Please understand that while tiles with rough or striped surfaces can undergo Hydrotect processing, the self-cleaning function, which uses its photocatalyst function to loosen staining components so that they are washed away by rainwater, may not be sufficiently exhibited.
  • If Hydrotect processing is performed, the color and polish will differ by various conditions, including the influence of the Hydrotect processing and clear enamel, the manufacturing factory, and the base color. Use a sample to confirm the conditions well before use.
  • We provide only oxidation firing tiles. We cannot provide reduction firing tiles. The characteristic texture of reduction firing tiles will be lost.