Buna n Bellows

Buna n Bellow, also known as Nitrile Rubber Bellows & NBR Bellows are mainly used as a cover or expansion joint for connecting moving parts and protect  inner components against oil, dust, water, grease, acids, bleaches, etc, also called protective cover and expansion joint bellows.

Buna n Bellows are produced by silicone rubber compression molding, extrusion moulding or rubber injection moulding.

Buna n Bellows Advantages:
1. Excellent Oil-proof:  Excellent oil resistance ranks only second to polysulfide rubber, acrylate and FKM

2. High tensile strength and wear resistance.
3. Good Heat Resistance:  Working Temperature ranging -35^oC-110^oC. (Short-period working: 120^oC)
4. Good air tightness
5. Strong Adhesion

Buna n Bellows Disadvantages:

1. Poor ozone resistance, against storage 

2. Poor electrical property

3. No resistance to aromatic solvents, halogenated hydrocarbon solvents and ketones & esters solvents

4. Low elasticity

Buna n Bellows Main Struction and Shape

Straight Convolution Buna n Bellows

Tapered Buna n Bellows

Metal + Buna n Overmolded  Bellows

Buna n Bellows with Clamp & Locks

Rubber Bellows Main Materials

Material	Abbreviation	Temperature Range	Aging Weathering Ozone	Resistance to Oil & Grease	Water Swell Resistance	Flex-Fatigue	Economy of Material	Material Notes
Chloroprene(Neoprene)	CR	-40F to 250F	Good	Good	Average	Very Good	Good	exposure to refrigerants,can be compounded for FDA applications
Nitrile	NBR	-22F to 212F	Poor	Very Good	Good	Good	Very Good	Automotive Applications, Good Oil Proof
Ethylence-Propylene	EPDM,EPM	-60F to 300F	Very Good	Poor	Very Good	Good	Very Good	Outside Applications, Good Weather Proof
Silicone	VMQ	-75F to 450F	Very Good	Average	Very Good	Very Good	Average	Medical Applications
Fluo Rubber	FKM	5F   to 390F	Very Good	Very Good	Good	Average	Poor	Rubber King, Widely Applications