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Factors in rubber compounds affecting the adhesion of polyester tire cords
Author(s) -
Iyengar Y.
Publication year - 1971
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1971.070150202
Subject(s) - natural rubber , polyester , materials science , composite material , curing (chemistry) , adhesion , compounding , modulus
Several factors in rubber stocks were demonstrated to be important in the adhesion of polyester tire cords to rubber compounds. The retained adhesion of polyester tire cords, determined after heat‐aging laboratory cord–rubber samples at elevated temperatures, was improved by (a) eliminating the sources of amines in the elastomers and compounding ingredients, (b) reducing the moisture content of the stocks, (c) increasing the overall water vapor permeability (WVP) of the cord–rubber composite, and (d) lowering the modulus of the stock. Sulfenamide cure accelerators and water were found to be synergistic in reducing the retained adhesion of polyester cord after in‐rubber aging at high temperatures. The harmful effects of amines released from sulfenamides during curing and heat aging were eliminated by compounding the stocks with accelerators that do not form amines. Aliphatic diamines present as nonrubber components in natural rubber (NR) were shown to be detrimental to adhesion. Since synthetic polyisoprene rubber (IR) does not contain any nonrubber components, IR stocks containing the nonamine accelerator benzothiazyl disulfide (MBTS) showed excellent retained adhesion to polyester cords. A recently developed nonamine‐type accelerator gave adhesion essentially equal to MBTS but showed excellent scorch safety and high stock modulus typical of sulfenamides. The retained adhesion in IR stocks after heat aging was less dependent on moisture level and stock modulus than in NR stocks. Finally, examples of practical rubber compounds giving improved retained adhesion to polyester tire yarns are given.