the influence on the relative increase in the mfi for various p i such as hdpe ldpe lldpe vldpe eva pp etc is comparable with regard to the mechanical properties however in some cases there are major differences in the effect of different p j for the same p i as well as in the effect of an individual p j for different p i an investigation of the basic relationships revealed the following tendencies although deviations therefrom and exceptions can always occur and the processing and crystallisation conditions also play a role a high density of p j especially correlates with the melting point when the molecular weight distribution of p j is narrow and results in a significantly increased crystallinity of the mixture with p i as a result of which the modulus of elasticity and yield stress increase and astonishingly this is also the case with a broad molecular weight distribution although the effect is usually less strongly defined which is why molecular weight distributions having polydispersivities lt 20 especially lt 15 most preferably lt 10 are preferred the molecular weight distribution is frequently not known for waxes but is reflected in the width of the melting or softening range where narrower intervals are preferred in the combination of a p j with different p i the ratio of the degree of polymerisation of the sequence length of p i dps p.