Polyurethane ( PU ) is in the nineteen seventies began as a sole

Material. Its main advantage is that it is hard, durable, pliable,

And to a large range of density are elastic. Therefore, PU in many fields are widely used, from the bottom to the inner bottom, the bottom material occupies 7% market share of the market. Previous systems using adipic acid polyester, though it is still used in some polyether PU, but most ( 83%) sole or polyester PU ( PU is polyester polyester and isocyanate and polyether combination, and PU is a polyether with isocyanate together. ). Because of the physical properties of polyester PU comparative superiority ( harder, more wear-resisting and so on ), because of his internal hydrogen bonding capacity. It can also prevent the oil and solvent, particularly suitable for protective footwear.

However, ester PU shoe material is the key issue: it is susceptible to hydrolysis and microbial invasion, the result is physical properties substantially reduced, quality level of atrophy, crack ( Fig. 1), thus greatly reducing the service life of the shoe. These factors in the high temperature and high humidity conditions, will be more severe, so in hot and humid environment state is more significant. At some point, footwear must be stored ( or the container shipping, conditions are very bad ) for a long time, to reach the terminal consumer, the shoes, also became the" new" shoes, its quality is far worse. Ester PU is another problem of low Wen Ling activity is poor, because of the moderate part of easy crystallization of adipic acid. So the similar materials at low temperature have great limitation. Due to its special chemical structure, two poly technique avoids these problems.

What is the two dimer fatty acid?

After the pressure, temperature and heterogeneous catalysis of composite reaction, soybean oil or oil in the unsaturated fatty acid can be extracted two dimer fatty acid. Two dimer fatty acid is a bifunctional molecules, can easily become one part of the polymer, such as polyamide and polyester. Its structure is irregular, containing a large number of isomers, thus completely crystallization. It also contains 36 carbon atoms, the hydrocarbon characteristics make two polycarboxylic acids and any containing this substance polymer extremely hydrophobic behavior. Hydrocarbon properties and crystallization characteristics of combined, makes the product even at very low temperatures, but also can keep the good elasticity.

Two dimer fatty acid used to make PU products, such as synthetic rubber, foam, porous foam, coatings, adhesives and sealants. In these applications, two dimer fatty acid value of technology is high, have the following properties:

Of hydrolysis / thermal oxidation / UV unique combination

Of low temperature flexibility

In general has adhesion

Water resistance performance of

Of impact resistance performance

In the footwear industry, application of two dimer fatty acid technology, is to deal with the ester soles system serious instability, and it on hydrolysis and microbial invasion of the susceptibility. If you do not use the traditional PU system esters, and using two polyester polyol, two dimer fatty acid is not easy to get the characteristic, coupled with a closed chamber structure, and its molecular weight characteristics, the results obtained are: better hydrolytic stability, resistance to microbial invasion characteristics, and sole longer life.

In two dimer fatty acid technology based on Uniqema, developed a special polyester polyols. Priplast is part of a range of ( Priplast is composed of 36 carbon two poly acid made from polyester polyols ), it does not use additives to solve this problem. Humid aging status test (see Fig. 2 and 3 ), in which the water vapor amount to 70 degrees, 100% relative humidity, test shows that, despite starting performance is slightly reduced, after a short wet after aging, this new form of PU over adipic acid industry standard. Compared with the standard, it also has maintained a very good mechanical properties. From this we think, the sole life really should substantially increase, and may be more increased by two times.

Natural plant oil

The use of Priplast and conventional additives, the stability is very different, because the Priplast technology is actually changing the material of the structure, so it has more reliable performance. In addition, because the products derived from natural plant oil, the technology is safe and not expensive, while the common additives do not. In addition, it comes from the plant characteristics, also means that it is not affected by rising oil prices impact.

It is also found that this material has many other advantages for sole. Including, at low temperatures is very flexible, satisfactory compression deformation and elastic properties, so in the footwear industry, and can be widely applied. The material has been in a number of footwear industry in the application, such as spray paint, adhesive and foam material. According to observation, protective shoes is one of the major markets, with it 's products have been in many PU system evaluation, the results are very good.