Properties and Features of Various Rubbers

Features

Approximate Shore hardnesses of urethane and rubber

Approximate hardness

- Permissible range of hardness: ±5 of the stated value.

Gel hardness

Gel hardness is expressed in terms of Asker C and needle penetration.
An approximate correlation between Asker C and Shore A, which is a measure of the hardness of urethane and rubber, is shown below.

*The needle penetration measurement is standardized in JIS K2207. A needle of a regulated weight is inserted vertically into a sample, and the hardness of the sample is determined from the length of the needle’s penetration.

A needle penetration value of 1/10 mm indicates needle penetration 1. (The higher the number, the softer the material.) It is, therefore, difficult to make relative comparisons with Shore or Asker, and hence a comparison chart has not been provided.

Property Comparison Graph

Property Order

Comparison of Chemical Resistance

Comparison of heat resistance: Vulkollan® can be used for a prolonged period at 80°C, and for a short period of 15 to 20 minutes at 120°C. Heat-resistance temperature (°C)

Values of Properties

Item	Unit	Urethane					Low-resilience urethane	Ultra-low hardness urethane
Specific gravity	−	1.13	1.13	1.20	1.15	1.20	1.03	1.02
Hardness	Shore A	95	90	70	50	30	70	15
Tensile strength	MPa	44.1	44.6	31.3	27.4	18.5	11.8	0.6
Strain	％	400	530	650	690	600	250	445
Heat resistance	℃	70	70	70	70	70	70	80
Cold resistance	℃	−40	−20	−20	−20	−20	−20	−40

Each tensile strength and strain value has been tested in accordance with JIS standard K6251.

Comparison of Properties of Urethane (Ether-based and Ester-based)

Characteristics		Ether-based (Shore A95/90)	Ester-based (Shore A70/50/30)
Tensile strength			○
Strain			○
Tear strength			○
Rebound resilience		○
Abrasion resistance	Sliding wear		○
	Impingement wear	○
Hydrolysis resistance		○
Oil resistance			○
Strength			○
Durability			○
Acid resistance, alkali resistance		○

Values of Properties

Each tensile strength and strain value has been tested in accordance with JIS standard K6251.

Item	Unit	Nitrile rubber		Chloroprene rubber		Ethylene rubber		Butyl rubber		Fluoroelastomer		Silicone rubber		High-strength silicone rubber	Low-elasticity rubber
Specific gravity	−	1.6	1.3	1.6		1.2		1.5		1.8	1.9	1.2	1.2	1.2	1.3	1.2
Hardness	Shore A	70	50	65		65		65		80	60	70	50	50	57	32
Tensile strength	MPa	12.7	4.4	13.3		12.8		7.5		12.5	10.8	7.4	8.8	7.8	8.3	10.3
Strain	％	370	400	460		490		380		330	270	300	330	400	810	840
Maximum operating temperature	℃	90	99	100		120		120		230	230	200	200	200	60	60
Continuous operating temperature	℃	80	80	80		80		80		210	210	150	150	150	30	30
Cold resistance	℃	−10	−10	−35		−40		−30		−10	−10	−70	−70	−50	10	10

Adhesion of Urethane, Rubber, Sponge

For products with seals, double-sided adhesive seals that are suitable for the material are used.

Double-sided adhesive seals and adhesives for urethane, rubber and sponge are also sold separately on the manufacturer’s website.

Model				W	Compatible rubber material	Base material	Main constituent
Standard type	Heat-resistant type	Conductive type	Oil-resistant type
ADTR	−	LADTR	PLADTR	20	Nitrile, chloroprene, ethylene, butyl, fluorine	Non-woven polyester	Acrylic pressure-sensitive adhesive
				50
ADTS	HADTS	−	−	20	Silicone	Standard: Polyester film Heat-resistant: Polyimide film	Silicone pressure-sensitive adhesive
				50

LADTR rolls are 5 m in length; the rest are 10 m.
Only the white release-paper side (silicone adhesive side) of ADTS adheres to silicone rubber.

Adhesive Strength Test Data

180° peel test: A rubber sheet 1 mm thick, 25 mm wide is glued to a SUS304 plate. The load required to peel the two components apart is expressed in terms of adhesive strength (N).

Conditions	Standard type						Heat-resistant type	Conductive type
	ADTR					ADTS	HADTS	LADTR
	Nitrile	Chloroprene	Ethylene	Butyl	Fluorine	Silicone	Silicone	Nitrile	Chloroprene	Ethylene	Butyl
Room temperature × 20 minutes	60	60	60	60	60	13	3	6	6	6	6
Room temperature × 72 hours	80	80	80	80	80	15	9	9	9	9	9
80°C × 48 hours	70	70	70	70	70	15	10	13	14	12	12

The above adhesive strengths are examples of measured values, and are not guaranteed values.

Item		Oil-resistant type
		PLADTR
		Special-grade acrylic pressure-sensitive adhesive	General acrylic pressure-sensitive adhesive (comparative reference value)
Adhesive strength (N)	Normal	11	11
	*Oil surface	9	3

*Oil surface: Measured 2 hours after applying salad oil to SUS board using cotton wool
Test method: 180° peeling test (adhesion of PET film 25 µm thick and 25 mm wide to SUS304 plate)

Discoloration of Urethane

Urethane tends to discolor and turn yellow over the course of time.
Discoloration is particularly noticeable in antistatic urethane (gray color), but this does not affect its physical properties or characteristics.
The process of discoloration over time is shown below. Carefully consider this before using.

- Discoloration of antistatic urethane over time

White rubber may also turn yellow over the course of time. Be sure to thoroughly understand this tendency before using urethane.

Recommended Products

PDF list