Resin soap

Resin soap is a mix of salts (usually sodium) of resin acids (usually mainly abietic acid). It is a yellow gelatinous pasty soap with use in bleaching and cleaning and as a compound of some varnishes. It also finds use in rubber industry as an emulsifier. Often the soap is pretreated with formaldehyde and maleic anhydride.^[1]

Resin soap is made by reacting resin acids in wood with sodium hydroxide, as a byproduct of the Kraft process for manufacturing wood pulp. It is also called Kraft soap.

Acidification of the resin soap produces tall oil.

Pine soap is refined from resin soap via tall oil by acidification, refining and resaponification. ^[2]

References

^ Fiebach, Klemens; Grimm, Dieter (2000). "Resins, Natural". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a23_073. ISBN 3-527-30673-0.
^ Barnes, Tanya M.; Greive, Kerryn A. (2017). "Topical pine tar: History, properties and use as a treatment for common skin conditions". Australasian Journal of Dermatology. 58 (2): 80–85. doi:10.1111/ajd.12427. ISSN 1440-0960. PMC 5434829. PMID 26790564.

[1] Fiebach, Klemens; Grimm, Dieter (2000). "Resins, Natural". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a23_073. ISBN 3-527-30673-0.

[2] Barnes, Tanya M.; Greive, Kerryn A. (2017). "Topical pine tar: History, properties and use as a treatment for common skin conditions". Australasian Journal of Dermatology. 58 (2): 80–85. doi:10.1111/ajd.12427. ISSN 1440-0960. PMC 5434829. PMID 26790564.

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