Advantages of polyester material

Ester-based polymer materials are formed by polycondensation of alcohols and carboxylic acids, and most of them are polycondensation of polyols and polyacids, such as PET, PBT, PU, ​​PLA, PBAT, PC, etc. These polyester materials have many excellent physical and chemical properties performance, so it is widely used in production and life. For example, PET has good fiber-forming properties, mechanical properties, abrasion resistance, and creep resistance; PBT has good electrical insulation; PU has high strength, abrasion resistance, oil resistance, and good toughness; PLA and PBAT have excellent biocompatibility and are completely degradable. They are the most popular green environmental protection material at the moment.

Hydrolysis and autocatalytic hydrolysis of polyester materials

However, polyester materials generally have a shortcoming. They are easily corroded by water or moisture. In a humid environment, especially under high temperature and humidity conditions, the ester bond is prone to decompose to produce alcohol and carboxylic acid. This is due to water or acid. The degradation or decomposition of the polymer caused by the action of the polymer is commonly referred to as polyester hydrolysis.

Hydrolysis of polymer ester group:

R1OOC-R2-RCOOR3 + H2O → R1OOC-R2-COOH + R3-OH

Hydrolysis of polyester will produce carboxylic acid. In general, carboxylic acid will accelerate the hydrolysis reaction of ester group to further generate more carboxylic acid. This is the autocatalytic hydrolysis of polyester, which will further aggravate polyester material disabled.

Autocatalytic hydrolysis of polymer ester groups:

R1OOC-R2-RCOOR3 + R4-COOH → R1OOC-R2-RCOOH+R4-COOR3

The hazards of polyester hydrolysis

First of all, the rupture of polyester macromolecules will cause a decrease in molecular weight, which will cause the physical properties of the polymer to decrease, until it loses its performance. The hydrolysis of polyester is the root cause of the decrease in its service life! For example, the cracking of polyester film; the separation of the encapsulation of the polyurethane roller from the roller core; the hydrolysis of polylactic acid film is too fast, and it has been decomposed and cannot be used during the shelf life; the monofilament of the polyester filter is cracked.

How to effectively alleviate the hydrolysis of polyester materials?

Adding HyMax® anti-hydrolysis agent is an effective means to alleviate the hydrolysis of polyester materials. HyMax® is a carbodiimide material. The highly active carbodiimide group contained in it can react with the carboxylic acid generated by the decomposition of the ester group to form stable urea-based compounds without side effects, thereby slowing down the progress of polymer hydrolysis, prolonging the service life of the polymer, and solving the problem of comprehensive performance degradation caused by hydrolysis of polyester materials.

HyMax® reacts with carboxylic acid:

R1-N=C=N-R2 + R3-COOH → R1-NH-CO-N-R2-COR3

At present, HyMax® has successfully helped customers in various fields such as film, leather, adhesives, plastics, coatings, etc. solve the problem of material failure caused by polyester hydrolysis.