Seeflex 040E is very strong and has been used with sugar, crystallized lactose, aggregates etc. Installing with an internal flow correction system is an additional way to further improve the system and avoid undue abrasion.
This will depend somewhat on what is in the laundry soap. In general the Seeflex 040E will work well. There is often Sodium Carbonate or Sodium salt which may start to break down the Seelfex over an extended period. Unilever in New Zealand run the BFM® fitting on soap product without issue.