Many factories in China also are considering the production of polyester/polyurethane conjugated materials. China already has excessive production capacity for polyester fiber, therefore, many textile factories in China are striving to develop stretch fabric textile products.

Particularly, Shaoxing, Wujiang and Nantong where they have major textile production sites have a strong wish to do so. Most factories in those areas are trying to produce conjugated textile products of polyester and other textile materials in order to shift from the production of regular goods to high value goods, so that they can be more competitive at a global level and make high profits. Right now they are only making polyester/polyurethane products for trial and have not yet established dyeing & printing technology specialized for the products.

In China, many factories still have problems with uneven dyeing even when they dye pure polyester. Their goal is to find the causes of the problem by the end of 1998.

We can think of various causes of uneven dyeing. One could be the water quality.

Adding chelating agents during the scouring process will, most of the time, prevent uneven dyeing and off-shade, however, most factories do not actually adopt this procedure since it is expensive.

Most textile factories in China check the condition of the cloth after scouring only with the naked eye. If they do not see anything, they will let it go without checking precisely. They only pay attention to the visible problems of uneven dyeing and deal with them one at a time. Pretty soon, they will find out how difficult it is to discern with the naked eye whether scouring is complete or not.

Right now, a German buyer is requesting a textile factory (not Japanese owned) in Nantong, China to produce polyester/nylon conjugated fiber for trial before actual mass production. It is necessary to understand staining problems on the nylon side and the importance of reduction clearing prior to dyeing polyester/nylon conjugated fiber, however, the factory does not seem to care about it very much.

In the case of dyeing polyester/polyurethane blended or polyester/nylon 6 blended fabric, it is necessary to choose the most suitable disperse dyestuffs. However, no matter how good the dyeability of the disperse dyestuff chosen, poor finishing will occur if scouring before dyeing fails. It all depends how soon the factories in Shaoxing and Wujiang earlier mentioned, as well as the factories in Nantong note this fact.

When scouring polyester/polyurethane blended or polyester/nylon 6 blended fabric, it is necessary to add, in either case, appropriate scouring agents, as well as chelating agents. In addition, even during reduction clearing which is always necessary after dyeing, the same reduction clearing agent can be used in both cases.

Without using chelating agent, cotton fabric was dyed with reactive dyestuffs.

Using chelating agent, cotton fabric was dyed with reactive dyestuffs.

From this, if textile factories in China succeed in dyeing polyester/nylon 6 blended fabric, dyeing polyester/polyurethane blended fabric may become possible. However, it is hard to say that it will happen within this year, and if Japanese buyers request Chinese factories to dye polyester/polyurethane blended or polyester/nylon 6 blended fabric, technical guidance will be necessary.

Whether Chinese textile factories can realize polyester/polyurethane-blend dyeing or not may also depend on technical guidance from Japan.

In Japan, all the basic technologies and quality labor force necessary for such a dyeing process have already been lined up, therefore, dyeing polyester/polyurethane conjugated fabric for mass production is possible as soon as someone decides to do it. Here, quality labor force means that in the Japanese textile industry, as well as other related industries in Japan, engineers from various companies in the same field want to exchange ideas and cooperate with each other to develop a new technology. Even within a company, one engineer tries to teach what he has learned to other workers. This is how companies help each other to find the best ways in approaching new technology.

Speaking of the expansion of the use of polyester/polyurethane blended materials in Japan, strengthening the above cooperation and the effort of each engineer at factory-level can easily open up new frontiers.