Infrared properties of Planetary Nebulae with [WR] and $wels$ central stars
We report the IR properties of planetary nebulae with WR type and $wels$ central stars known to date and compare them with the IR properties of a sample of PNe with H-rich central stars. We use near-, mid- and far-IR photometric data from archives to derive the IR properties of PNe. We have constructed IR colour-colour diagrams of PNe using measurements from $2MASS$, $IRAS$, $WISE$ and $Akari$ bands. [WR] PNe have a larger near-IR emission from the hot dust component and also show a tendency for stronger 12$\mu$m emission as compared to the other two groups. Cool AGB dust properties of all PNe are found to be similar. We derived the dust colour temperatures, dust masses, dust-to-gas mass ratios, IR luminosities and IR excess of PNe for these three groups. [WR] PNe and $wels$-PNe tend to have larger mean values for dust mass when compared to the third group. The average dust-to-gas mass ratio is found to be similar for the three groups of PNe. While there is a strong correlation of dust temperature and IR luminosity with the age for the three groups of PNe, the dust mass, dust-to-gas mass ratios and IR excess are found to be non-varying as the PNe evolve. [WR] PNe and $wels$-PNe show very similar distribution of excitation classes and also show similar distribution with Galactic latitude.