Rubber parts are used in various industries. According to different requirements from different industries, rubber parts need to be oil-resistant, heat-resistant, wear-resistant, ozone-resistant, low-temperature-resistant, acid/alkali resistant, etc. We use different formulas to adjust the properties, and test the material with precision instruments in specific situation simulations to ensure the rubber parts be suitable, durable, and stable. Our RD department is dedicated to testing rubber formula properties, and also works with third-party inspection institutions to ensure that products meet the requirements of environmental restrictions and become a trustworthy supplier.


Rubber formulas perform properties that are evaluated through the standard test to judge the applicability and service life. We follow two major testing standards: the American Society for Testing and Materials International ( ASTM )and the Japanese Industrial Standard (JIS). The original properties include hardness, elongation, tensile strength, and specific gravity. By testing heat-resistant, oil-resistant, low-temperature-resistant, ozone-resistant, compression test, and insulation value, we compare the test value variation of hardness, elongation, tensile strength, and volume with original properties and provide our customers with stable rubber products.

Test Instrument
1. Moving Die Rheometer, Mixing Grader, Mooney Viscometer: Confirming the vulcanization characteristics of rubber compound.
2. Durometer: hardness.
3. Densimeter: specific gravity.
4. Tensile tester: elongation and tensile strength
5. Organic Solvent Soak test: volume change.
6. Bursting test machine: pressure resistance of rubber hose.
7. Plug gauge, pin gauge, and vernier caliper: inside and outside diameters.
8. Submerging machine: leaking test
9. CCD glass disc AOI machine: dimensions and the surface of rubber parts.
10.2.5D auto video measure machine: precise dimensions of rubber parts.
Mooney Viscosity
Moving Die Rheometer
Mixing Grader
Tensile Tester
Organic Solvent Soak Test
Japanese ALFA Densimeter
GS-760N Durometer
Pin Gauge
Japanese Mitutoyo Vernier Caliper
Plug Gauge
Submerging Machine
CCD Glass Disc AOI Machine
2.5D Auto Video Measure Machine
LeeKuma has cooperated with Taiwan Rubber Research & Testing Center (TRC), and Plastics Industry Development Center (PIDC) to do tests of material determination and properties for special requirements.
Material Introduction

Natural Rubber originates from Hevea Brasiliensis, and its excellent elasticity and resilience are applied to industry. To meet more special requirements, people refine petroleum to get synthetic rubbers.

Rubber Material Properties
ACM Acrylate Rubber Oil Resistance, Heat Resistance
CR Chloroprene Rubber (Neoprene) Ozone Resistance, Weather Resistance, Chemical Resistance
CSM Chlorosulfonated Polyethylene Rubber Heat Resistance, Corrosion Resistance
EPDM Ethylene-propylene Rubber Acid and Alkali Resistance, Heat Resistance, Ozone Resistance, Solvent Resistance
FKM Fluoro Elastomer (VITON) Fuel Resistance, Acid and Alkali Resistance, Heat Resistance
HNBR Highly Saturated Nitrile Rubber Heat Resistance, Chemical Resistance
MQ Silicone Rubber Heat Resistance, Weather Resistance, Ozone Resistance
NBR Nitrile Rubber Oil Resistance, Solvent Resistance
NR Natural Rubber Wear Resistance, High Elasticity, High Tensile Strength
PU Polyurethane Oil Resistance, Wear Resistance
ACM Acrylate
Oil resistance, aging resistance, heat resistance, and ozone resistance are better than NBR, silicone, and FKM. Apply to high temperature and oil resistance parts in the automobile industry.
Apply to heater hoses, sealing parts, high temperature, and oil-contacted rubber cable sheaths in the automobile industry.
CR Chloroprene Rubber
CR material has chemical resistance, weak acid resistance, wear resistance, weather resistance, and flame retarding properties. It’s suitable for outdoor parts.
It’s used to produce corrosion-resistant, heat-resistant, and flame retarding rubber products, like rubber hoses, rubber cable sheaths, shoes, tires, washers, etc. Good acid and alkali resistance and weather resistance are suitable for marine rubber parts.
CSM Chlorosulfonated
Polyethylene Rubber
High elasticity, High resilience, high-temperature resistance (150℃), ozone resistance, weather resistance, insulating, and oil resistance
Apply to ignition wires, spark plugs, rubber hoses, and sealing parts in the automotive industry. High resilience is suitable to produce rain coats, tarpaulin, and waterproof cloth.
EPDM Ethylene-propylene
Steam resistance, high-temperature resistance (150℃), chemical resistance, acid and alkali resistance, ethanol resistance, aging resistance
Apply to car door seal, radiator, rubber hose, gasket, cable insulating parts, high temperature resistant & high-pressure steam hose, printing rubber roller, and packing contacted with propanol and ester ink.
FKM Fluoro Elastomer
Graded by fluoroelastomer contents. High-temperature resistance, aromatic solvent resistance, alkali resistance, fuel resistance, and solvents resistance properties are the best among all kinds of rubbers.
Usually made into high temperature resistant, and acid & alkali resistant o-rings and washers. Air tightness characteristic is suitable to make into fuel hose.
HNBR Highly Saturated
Nitrile Rubber
Wide range of operating temperature resistance, high temperature can reach 150 ~ 165 ℃, and low temperature can reach -30 ~ -40 ℃. Compare to NBR, HNBR has better physical and mechanical properties when contacting diesel, acidic substances, and methane in high-temperature environments.
Apply to high temperature and oil-resistant hose, rubber roller, oil seal, o-rings, and sealing rings.
MQ Silicone
Easy to release, excellent high-temperature resistance, chemical resistance, acid & alkali resistance.
Wide range of operating temperature resistance is suitable to make sealing parts, radiator hoses, and turbine hoses, Exhaust Fume Hoses for the aerospace and automotive industries. It can also be used in home appliances, such as washers and water hoses in coffee machines, sealing parts of reusable lunch boxes, and oven silicone strips. And its insulation property is applied to electronic and electrical industries. Its chemical resistance is suitable in some medical parts. It can be widely used in different industries.
NBR Nitrile
Resist to ink, mineral oil, plant oil, and other solvents. Low compression set, good elasticity, tensile strength, wear resistance, oil and fuel resistance.
Compounding with PVC can improve ozone and weather resistance. It’s usually made into an industrial rubber fuel hose, hydraulic oil hose, oil seal, printing roller, wear-resistant rubber belt, etc.
NR Natural
Excellent wear resistance, high elasticity, and mechanical properties.
It's an important material for tires, rubber belts, rubber hoses, rubber shoes, shockproof products, and rubber fenders; Excellent resilience property is applied to sporting equipment; Conveying rubber belt and rubber tile.
PU Polyurethane
Oil resistance, solvent resistance, excellent tensile strength, and wear resistance.
The biodegradable property is wide used in soles and heels; wear resistance is applied to rubber rollers of printing and textile industries, and truck solid tires.
RoHs & Reach

Recently, international requirements become stricter, especially RoHs and Reach, which the USA and EU governments request all imported products to comply with these restrictions, and restrict the use of hazardous substances: lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE), etc. In response to these environmental regulations, LeeKuma keeps improving R&D to meet the updated regulations; Besides these two restrictions, we develop a new formulary to meet Polycyclic Aromatic Hydrocarbons (PAHs) category 2, limitation of the sum of 18 hazardous substances and Phthalates, etc. to confirm the products complied with importing country requirements.

Test Method
LeeKuma cooperates with different laboratories to do tests and gets the third-party inspection report. Labs are Taiwan Rubber Research & Testing Center (TRC), Plastics Industry Development Center (PIDC), TÜV Rheinland, Intertek, and SGS Taiwan Ltd.
QA International Certification Limited(QAICL)
ISO 9001:2015
Chinese National Standards CNS Liquefied Petroleum Gas (LPG) Hose,
License No.D53214
Taiwan Plastics Industry Association
Membership Certificate
High Pressure Rubber Hose Patent Certificate and License
TRC Test Report, ROHS 2.0
SGS Reach
Intertek Test Report,
TÜV Rheinland Test Report
dun & Bradstreet's D-U-N-S Certificate
Taiwan Rubber & Elastomer Industries Association,
Top Level Membership Certificate