Heptane-modified resins

Table 2. Comparison of properties of toluene-modified and heptane-modified resins ...

Characteristics Heptane-modified resin Toluene-modified resin... 

Aniline and mixed aniline point (DIN 51 775 modified). It is similar to the cloud point test except that the solvent is aniline, a very polar liquid. The aniline point is defined as the temperature at which a mixture of equal parts of aniline and the resin show the beginning of phase separation (i.e. the onset of clouding). Phase separation for aromatic resins occurs between I5°C and below zero for resins with intermediate aromaticity, it lies between 30 and 50°C and for non-aromatic resins, it is 50 to 100°C. Sometimes the mixed aniline point is used. It is similar to the aniline point except that the solvent is a mixture of one part of aniline and one part of w-heptane. The problem of both procedures is that precipitation of resins can be produced before the cloud is generated. 

As the cylinder rotates in the press, the lower part of the cylinder is flooded with ink having a viscosity in the low centipoise range. The press ready ink may contain 7% pigment, 18% binder, such as modified rosins, nitrocellulose or a synthetic resin and 75% solvent. The solvents are usually blends of such materials as aliphatic hydrocarbons in the heptane range, toluene, acetates and alcohol. Water based systems are used in a number of applications. 

Acrylonitrile is used in the production of acrylic fibers, resins, and surface coating as an intermediate in the production of pharmaceuticals and dyes as a polymer modifier and as a fumigant. It may occur in fire-effluent gases because of pyroly-ses of polyacrylonitrile materials. Acrylonitrile was found to be released from the acrylonitrile-styrene copolymer and acrylonitrile-styrene-butadiene copolymer bottles when these bottles were filled wifh food-simulating solvents such as water, 4% acetic acid, 20% ethanol, and heptane and stored for 10 days to 5 months (Nakazawa et al. 1984). The release was greater with increasing temperature and was attributable to the residual acrylonitrile monomer in the polymeric materials. 

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