T25 - Chemical Fabrics

Chemical fiber is a general designation of fiber which was made through chemical and physical ways using crude or man-made macromolecule compound as materials.  According to the different material sources, chemical fiber is classified into man-made fiber and synthetic fiber.  

Generally speaking, the solution of macromolecule compound is extruded through very small holes of spinnert to form fibres.  The production can be continuous filament yarn, multifilament bundle uncut or discontinuous fiber.

To showcase the different stages in the production of chemical fiber, a set of five stamps was released on June 15,1978.  This stamp set of five was also the first time that a stamp set was printed in continuous strip format together.  

(5-1) 8 fen, Material feeder  原料
(5-2) 8 fen, Drawing out threads  抽丝
(5-3) 8 fen, Weaving  纺织
(5-4) 8 fen, Dyeing and printing  印染
(5-5) 8 fen, Finished products  成品

(5-1)【Material feeder】 Polymerization is the formation of macromolecules through repetition of basic units.  Initially, the various components are solids and first must be converted to a liquid state to be extruded into fibers.  The materials are chemically converted, dissolved, or melted, turning into a thick liquid.  The stamp showed a material feeder with factory facility in the background.

(5-2)【Drawing out threads】 A spinning process produces the fiber by passing the thick liquid through a spinneret.  A spinneret is a device with hundreds of holes of a specified diameter.  The liquid is forced through the spinneret holes and comes out a string liquid filament.  The hole in the spinneret determines the diameter of the filament, which is set by the application.  The stamp showed the extruded fiber collecting on rollers and drawing out threads.
 
(5-3)【Weaving】Weaving is a method of fabric production in which two distinct sets of yarns or threads are interlaced at right angles to form a fabric.

(5-4)【Dyeing and printing】The stamp showed red, yellow and blue as primary colours, which can be combined through dyeing to make a useful range of colors for the fabrics.

(5-5)【Finished products】The stamp showed the multi-colors and beautiful finished fabric products. 

T25 – Chemical Fabrics  化学纤维 Issue Date: 1978.6.15
Serial Number:	T25
Scott Number:	1405-1409
Michel Number:	1415-1419
Number of stamps in Set:	5
Denomination:	8 fen for stamp 1, 2, 3, 4, 5
Quantity of Issue:	15,000,000 for stamp 1, 2, 3, 4, 5
Perforation:	P11 X 11½
Sheet Composition:	50 (5 X 10) for stamp 1, 2, 3, 4, 5
Size of stamps:	40 X 30 mm for stamp 1, 2, 3, 4, 5
Designer:	Wu Jiankun  吴建坤
Printing Process:	Photogravure
Printing House:	Beijing Postage Stamp Printing Works