Boiling water shrinkage

Boiling-water shrinkage, about 1%. Good resistance to shrinkage in dry heat, w ith about 5% shrinkage at 390JF 1200 C). Pressure and heal at 300 F + < I50 C+1 may cause stiffening and discoloration."... 

The boiling water shrinkage of standard acrylic fibers is generally quite low, as seen in Table 12.19, but may be made intentionally high for special types of fibers. High-bulk fibers that have been stretched and cooled to retain a frozen-in strain are designed to shrink up to... 

Dimensional stability of fibers is critically important in many applications. The linear thermal expansion coefficient discussed above can be used to describe the dimension stability of fibers. However, in practical applicatiorts, the thermal stability of fibers is commonly evaluated by boiling water shrinkage BWS) measiue-ment. During the measurement, fibers are placed in boiling water and the BWS value is obtained at equilibrium by using the following equation ... 

Amino resins are fabricated principally by transfer and compression molding. Injection molding and extrusion are used on a limited scale. Urea resins are not recommended for outdoor exposure. The resins show rather high mold shrinkage and some shrinkage with age. The melamines are superior to the ureas insofar as resistance to heat and boiling water, acids, and alkalis is concerned. 

TABLE 9.2 Shrinkage of GeoDeck composite hollow deck boards (unbrushed) in boiling water... 

Time for exposure of boards to boiling water (min) Shrinkage measured after 24 h of cooling and conditioning (%) Moisture of the boards after 24 h Moisture of the boards after 48 h... 

Shrinkage was measured 24 h after the boards were immersed into boiling water and pulled out. Water had an access to the material from both outside and inside of the boards. 

Solid, mp 290-295. Bums slowly. Sp gr 1,22. Fiber has good resistance to acids and alkalies. Treatment of fabric with trichloroethylene and methylene chloride causes it to shrink boiling water and perchloroethylene induce slight shrinkage. Fabric has good crease resistance. 

Fig. 2. Shrinkage of different PET fibers in boiling water and then in hot air (up to 200 C (1) PET hotnopolymer, standard type (2) FET honx lymer, highrshrinkage type (3) PET copolyimr, for knitted goods (4) PET (Xtpcdymer, for woven goods...

Nearly amorphous filan ts of PET ((17) = 0.S7), spun at 295 °C at 100 m/min, are dipped in boiling water, and drehiid 1 2.5 at a rate of 500 m/min. By treat-ii the fOainents in the relai state with wata at 70 C, crinqi is fonned Undrawn filaments of T are swdlen in viater at 30—40 C and stretdied by 600% at about 50 °C. After shrinkage in damp medium, crimp is developed 1 steam at temperatures between 130 and 210... 

FIGURE 4.31 Effect of heat-setting temperature and time on the shrinkage of polyvinyl chloride fiber in boiling water. 

Because of its low crystallinity, the PVC fiber is poor in dimensional stability at high temperature. Shrinkage occurs near the glass transition temperature (85°C), and fiber manufactured below normal heat-treatment conditions shrinks by 4(C60% in boiling water. This characteristic may be a defect, but various applications are under development to make use of this property. 

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