BACKING AND THEIR CHARACTERISTICS

As illustrated at page 1.1 the brush backing is the element where the staple, fastening the tuft, is inserted. Normally the backing is made of relatively not too hard material, such as synthetic substances or wood. Some metallic material, such as aluminium or brass, can also be used if we exploit the buckling of the staple.
Any kind of backing can be used in manufacturing brushes which will work in 'normal' conditions, for example at room temperature, with non acids, no humidity and under no heavy stress : the choice will depend either on the overall quality of the brush or on economy considerations. On the other side the backing will be chosen according to merely technical considerations for brushes working in particular conditions.
Table 1.2 reports the most common materials and their uses.
Table 1.3 reports the main physical and mechanical characteristics of the
backings.

 

TAB 1.2

BACKING	PARTICULAR USES
PVC	ACID ENVIROMENT - TOOLING
NYLON	FOOD INDUSTRY
POLYPROPYLENE	FOOD INDUSTRY - HUMID
ACETAL RESIN	FOOD INDUSTRY - TOOLING
WOOD	HIGH TEMPERATURE
ALUMINIUM	HIGH TEMPERATURE - ELECTRIC CONDUCTIVITY
BRASS	HIGH MECHANICAL STRENGHT

 

TAB 1.3

	PS	A	T	R	RE	RA
PVC	1.40	0.05	60	5.5	10 E15	B
NYLON	1.13	10	110	7.2	10 E11	S
POLYPROPYLENE	0.90	0.02	105	3.4	10 E16	D
ACETAL RESIN	1.41	0.9	110	6.5	10 E14	S
WOOD	0.72	2.5	300	13.4	20	S
ALUMINIUM	2.70	-	500	33.4	2.8*10E-6	D
BRASS	8.50	-	800	46.0	7*10E-6	B