| 释义 |
▪ I. ˈovercure, n.
[over- 29.]
The process or result of overcuring; overvulcanization.
1915Jrnl. Soc. Chem. Industry 15 Oct. 990/1 The load at breaking point was found to increase with the time of cure to a certain point and then to collapse, the rubber becoming very brittle at an overcure. 1952J. Delmonte Plastics Molding ix. 265 Translucent urea molded parts are the first to show the effects of overcure—by dullness or chalkiness in finished products. 1964[see overcuring vbl. n.].
▪ II. overcure, v.
(stress variable)
[over- 27.]
a. trans. To cure (plastic or rubber) for longer than the optimal period; to overvulcanize. Also absol.
b. intr. To undergo overcuring.
1916Jrnl. Soc. Chem. Industry 31 Aug. 872/1 It is..common in the case of many goods for manufacturers when vulcanising to undercure rather than overcure the rubber so as to avoid the danger of over-vulcanising and consequent deterioration. 1949B. L. Davies Technol. Plastics xxi. 405 The whole board is cured in the usual manner in the press, care being taken not to overcure. 1952J. Delmonte Plastics Molding viii. 211 Before the advent of thorough internal heating by high frequency, thick-molded parts would overcure on outside surfaces before the interior reached molding temperature. 1972Materials & Technol. V. xiv. 523 The outside of a thick rubber article has to be cured longer than the optimum curing time (overcured) in order to ensure an optimum cure within the article.
So ˈovercured ppl. a.; overˈcuring vbl. n.
1912Jrnl. Soc. Chem. Industry 16 Dec. 1100/1 It is important to note that (3) was almost fully cured at 35 lb. and over-cured at 45 lb. Ibid. 1101/2 Beyond this point it was probable that a decrease merely indicated overcuring. 1952J. Delmonte Plastics Molding ix. 265 An overcured plastics part is even more difficult to recognize than an undercured piece, primarily because most plastics are not critical in their time of cure. 1964A. E. Juve in Alliger & Sjothun Vulcanization of Elastomers ii. 30 Vulcanization occurs in three stages; (1) an induction period, (2) a curing or cross-linking stage, and (3) a reversion or over⁓cure stage... Some systems..have little or no tendency toward reversion or increased tightness of cure as the result of overcuring.
▪ III. overcure
obs. form of overcover. |