The SK10 – built for 21st-century water systems

The SK10 revolution in rubber materials

〈Evaluation results〉

SK10is Rubber materials which feature high resistance to degradation due to chlorine, ozone etc. as well as excellent durability against repeated displacement, pressure fluctuations etc., and which are also environmentally friendly

Example of carbon outflow due to rubber degradation in a clean water line

Example of carbon outflow due to rubber degradation in a clean water line

Exposure test

Exposure test① Exposure test②

High chlorine resistance

Chlorine impact evaluation documents

Elapsed time: One day Chlorine concentration of 3,000ppm at temperature of 80°C

Elapsed time: 15 days Chlorine concentration of 3,000ppm at room temperature of 23°C

Before test Elapsed time: One day Elapsed time: 15 days Results
SK10Before test SK10Elapsed time: One day SK10Elapsed time: 15 days Almost no surface
degradation has occurred
CRBefore test CRElapsed time: One day CRElapsed time: 15 day Surface cracking has occurred,
leading to penetration and
later hardening and degradation
EPDMBefore test EPDMElapsed time: One day EPDMElapsed time: 15 days High chlorine
penetration compared to CR

High ozone resistance

Ozone water infiltration test

Dissolved ozone concentration:

Dissolved temperature:

Oxygen flow rate:

External inspection:
Inspected at 5x and 40x magnification using a VH-7000 digital HD microscope.

Ozone water infiltration test


This product suffers little effect from ozone compared to traditional rubber.
We recommend fluoro carbon polymer flexible joints where ozone concentration is high such as directly after ozone disinfection or cleaning.

SK10 *No occurrence of cracking was observed Surface changes resemble EPDM;
while adhesion and whitening were observed, no foreign matter deposits could be observed.
CR *No occurrence of cracking was observed,
surface degradation was the fastest, and carbon black deposits were observed
EPDM *No occurrence of cracking was observed,
surface changes were slow compared to CR, but carbon black deposits were later observed.

High bending fatigue resistance

Physical property comparison   conducted at the Chemicals Evaluation and Research Institute

Ordinary state

Name of specimen SK10 CR EPDM
Hardness(Hs-JIS A) 60 62 62
Tensile strength(MPa) 23.8 16.0 24.0
Stretching(%) 700 480 700
Tearing strength(KN) 43 38 45

Aging test (Geer Type Aging Oven test, 96 hours at 100±1°C)

Name of specimen SK10 CR EPDM
Changes in hardness(Hs) +7 +12 +5
Rate of changes in tensile strength(%) +9 -4.6 -7.1
Rate of changes in stretching(%) -16 -21.4 -22.4

Testing method: JIS K 630-1995 “Vulcanized Rubber Physical Testing Method”
Notes: Room temperature of 23°C. Testing machine type: Load cell type 500N
Observations: Tensile strength increased in the aging test, the opposite to CR and EPDM.
This evaluation demonstrated that the product has excellent bending fatigue and cyclic fatigue resistance.
In addition, the repeated pressure fluctuation performance increased to over twice that of currently-available products.

Environmentally friendly

The SK10 causes reduction of approximately 43 tons of CO2 emissions annually (internal comparison)


Total CO2 emissions from manufacturing to disposal are reduced by half


Total CO2 emissions from manufacturing to disposal are reduced by 80%