EXAMPLES 1-14
The components (a) to (f) listed in Table 1 and corresponding to the individual examples were initially introduced, in the stated amount ratios under inert gas into a stirred autoclave. The contents were subsequently heated to 275.degree. C. and the mixture maintained at this temperature for 8 hours. The excess pressure produced was then reduced to atmospheric pressure, low-boiling components simultaneously distilling off, and the autoclave contents cooled to room temperature. In general, the yield is above 90%. The characteristics of the resins produced according to Examples 1 to 14 can be seen from Table 1a which follows.
Notes on Table 1a
The mineral oil compatibility is determined by dissolving the substance in a mineral oil designated "PKWF 4/7" manufactured by J. Haltermann, Hamburg. The linseed oil takeup in per cent by weight which is displayed by a 50% strength solution in "PKWF 4/7" until the onset of cloudiness indicates the linseed oil compatibility.
The thermal stability was determined by storing the examples tested for six hours at 230.degree. C. under a nitrogen atmosphere. The viscosities were measured, in each case in 50% strength toluene solution, before and after storage for 6 hours.
Results discussion
From Examples 2 and 3, the influence of the metal compounds on the properties of the cyclopentadiene resins obtained in which no dicarboxylic acid components were employed can be observed. Both the mineral oil and linseed oil compatibility is considerably increased by use of the metal compound, in this case magnesium oxide.
The comparison of Examples 4 and 12 C shows that the linseed oil compatability is significantly better when the resol component (b) is used. If the phenol component in the resol resin is varied by extending the alkyl chain, then not only a substantial improvement in the linseed oil compatibility, but also of the solubility in mineral oil, is obtained.
The advantages of the resins according to the invention in comparison to phenolic resin-free resins are also shown particularly in the case of the thermal stability, and thus of the storage stability. The incorporation of the phenol components produces considerably better stabilities.
The thermal stability when removing the resin melt after the end of the reaction is important when working under manufacturing conditions. The melt and solution viscosity of the resins should remain as constant as possible over a period of hours in this case in order to obtain uniform products. The addition of high boiling mineral oils after the completion of the reaction to reduce the melt viscosity and the discharge temperature is usually undesirable and unnecessary in the case of the resins according to the invention. Whereas the viscosity remains constant, within narrow limits, in the case of the resins prepared according to the invention, the comparison experiments show a considerable increase in viscosity and are thus difficult to handle under production conditions.