US 12,252,670 B2
Method of cleaning plastic with dispersant copolymer
Scott Backer, Phoenixville, PA (US); and Paul Mercando, Pennsburg, PA (US)
Assigned to Rohm and Haas Company, Collegeville, PA (US)
Appl. No. 17/056,613
Filed by Rohm and Haas Company, Collegeville, PA (US)
PCT Filed Jun. 10, 2019, PCT No. PCT/US2019/036259
§ 371(c)(1), (2) Date Nov. 18, 2020,
PCT Pub. No. WO2020/005516, PCT Pub. Date Jan. 2, 2020.
Claims priority of provisional application 62/690,458, filed on Jun. 27, 2018.
Prior Publication US 2021/0207066 A1, Jul. 8, 2021
Int. Cl. C11D 1/66 (2006.01); C11D 1/72 (2006.01); C11D 3/04 (2006.01); C11D 3/10 (2006.01); C11D 3/20 (2006.01); C11D 3/36 (2006.01); C11D 3/37 (2006.01); C11D 3/386 (2006.01); C11D 17/00 (2006.01)
CPC C11D 3/361 (2013.01) [C11D 1/66 (2013.01); C11D 1/72 (2013.01); C11D 3/046 (2013.01); C11D 3/10 (2013.01); C11D 3/2082 (2013.01); C11D 3/2086 (2013.01); C11D 3/3757 (2013.01); C11D 3/3761 (2013.01); C11D 3/3765 (2013.01); C11D 3/386 (2013.01); C11D 17/0008 (2013.01); C11D 2111/18 (2024.01)] 5 Claims
 
1. A method of cleaning a plastic article in an automatic dishwashing machine, comprising:
selecting an automatic dishwashing composition for cleaning plastic, wherein the automatic dishwashing composition, consists of:
a builder, wherein the builder is a mixture of at least one carbonate and at least one citrate;
a phosphonate;
a nonionic surfactant;
a dispersant polymer which has:
(a) 75 to 81 wt % of structural units of formula I

OG Complex Work Unit Chemistry
wherein each R1 is independently selected from a hydrogen and a —CH3 group and wherein R1 is a hydrogen in 98 to 100 mol % of the structural units of formula I; and
(b) 19 to 25 wt % of structural units of formula II

OG Complex Work Unit Chemistry
wherein each R2 is independently selected from a —C2-3 alkyl group and wherein R2 is an ethyl group in 98 to 100 mol % of the structural units of formula II;
wherein each R3 is independently selected from a hydrogen and a methyl group and wherein R3 is a hydrogen in 98 to 100 mol % of the structural units of formula II; wherein the dispersant polymer has a weight average molecular weight of 1,750 to 17,500 Daltons; and wherein the dispersant polymer has less than or equal to 1 wt % of structural units of sulfonated monomer; and
optionally, an additive selected from the group consisting of a bleaching agent a bleach activator, a bleach catalyst; an enzyme, a filler, a fragrance, a dye, a foam suppressant and mixtures thereof; wherein the bleaching agent is selected from the group consisting of sodium percarbonate, sodium perborate and mixtures thereof; wherein the bleach activator is tetraacetylethylenediamine; wherein the bleach catalyst is selected from the group consisting of manganese(II) acetate, cobalt(II) chloride, bis(TACN)magnesium trioxide diacetate and mixtures thereof; wherein the enzyme is selected from the group consisting of protease, amylase, lipase, cellulase and mixtures thereof; and wherein the filler is selected from the group consisting of sodium sulfate, potassium sulfate, sodium chloride, potassium chloride and mixtures thereof;
providing a plastic article, wherein the plastic article comprises a polystyrene tumbler; and,
applying the automatic dishwashing composition to the plastic article.