Effect Of Pbt Color Masterbatch On Shrinkage Of Loose Tube

 The stability performance of Anmei PBT low-shrinkage masterbatch in over-length shrinkage and post-shrinkage of large-wall thickness casing proved by tests

 

In the operation and maintenance of optical cables, splicing (fusion) is usually performed by identifying the color of optical cables. Different optical cables, different casings, and different optical fibers can be distinguished by color. Polybutylene terephthalate (PBT) is the main material for fiber optic sleeves. In the production process of the secondary sleeve, the PBT is formed into a loose tube by extrusion molding, which provides protection for the optical fiber in the sleeve. The excess length of the optical fiber or the optical fiber ribbon in the sleeve is the most important parameter in the secondary sheathing process, which largely determines the main performance of the optical fiber loss, cable stretching, and temperature characteristics.

 

As a polymer material, PBT is in a semi-crystalline state in the extrusion stage, and it has a tendency to post-crystallization after extrusion. In addition, further crystallization occurs with changes in temperature and time. The post-crystallization causes the post-shrinkage of the PBT sleeve, which further shortens the length of the sleeve and increases the excess length of the optical fiber in the sleeve. This uncontrolled change in excess length should be kept to a minimum during casing fabrication.

 

Post shrinkage is an inherent property of PBT materials. The addition of masterbatch to PBT not only colorizes the casing but also acts as a nucleating agent in the extrusion process, thereby affecting the crystallization process and crystallinity of PBT. Different manufacturers and different colors of masterbatch have different effects on the crystallinity and post-shrinkage of PBT due to differences in carrier resins or pigments, so the stability of the remaining length of the sleeve varies according to the color.

 

1. Test and Analysis

 

1.1 Test requirements:

 

The surface of the debugged casing is smooth and round, full of oil, the geometric dimensions meet the requirements, and the excess length and post-shrinkage meet the requirements of 0.3±0.3‰.

 

1.2 Test method:

 

In order to verify that the pa66 shrinkage effect of the Anmei color masterbatch on the PBT large-wall thickness loose tube is within the required range, we selected three styles of color masterbatches for comparative testing from well-known brands. Detect the current excess length and the excess length of the 1st day, the 3rd day, and the 7th day of each color masterbatch used for extruding the loose tube.

 

Suzhou Anmei modified plastic inc, the professional supplier of engineering plastic and the color masterbatch was founded in 2013, which is located in Tongli - the millennium ancient town, 50km far away from Shanghai, the location is very convenient for transportation.