Machine dish wash compositions

Details Machine dish wash compositions Machine dish wash compositions

2000-11-09

2001-10-30

Delcotto, Gregory (Department: 1751)

Cleaning compositions for solid surfaces, auxiliary compositions

Cleaning compositions or processes of preparing

For cleaning a specific substrate or removing a specific...

C510S224000, C510S229000, C510S467000, C510S477000, C510S478000, C510S488000

Reexamination Certificate

active

06310023

ABSTRACT:

TECHNICAL FIELD
The present invention is in the field of machine dishwashing. More specifically, the invention encompasses automatic dishwashing compositions.
BACKGROUND OF THE INVENTION
A common problem with detergent compositions for use in automatic dish washing machines is that they cause spotting and filming on crockery and glasses during the wash process. The spotting and filming is caused by the deposition of calcium salts.
The spotting and filming is a particular problem when a non-phosphate detergent is used. EP 0 659 874 (Procter and Gamble) recognises this problem and describes a carboxylate based builder system with ethyl 1-hydroxy-1,1 phosohonic acid and an organic polymer.
EP 0 364 067 (The Clorox Company) describes a machine dishwashing composition with alkali metal carbonate as the sole builder, an alkali metal silicate, a low foaming surfactant and a calcium crystal growth inhibitor which may be a phosphonic acid.
The present invention has found that the precipitation of calcium can be mitigated by the choice of chelating agent and builder.
Furthermore, compositions according to the present invention are particularly stable.
DESCRIPTION OF THE INVENTION
Accordingly, the present invention provides a detergent composition comprising sodium citrate and an organo monophosphonic acid or a salt thereof.
DETAILED DESCRIPTION OF THE INVENTION
Organo Monophosphonic Acids and Salts
The invention has an essential feature an organo mono phosphonic acid or a salt thereof having the following formula:
where n is an integer from 0 to 6 and X
1
, X
2
, X
3
are independently selected from an alkyl, alkenyl, aryl or carboxy group with the proviso that at least one of X
1
, X
2
, X
3
is a carboxy group.
Preferably, the organo monophosphonic acid has the structure
where n is an integer from 0 to 5.
More preferably, the organo monophosphonic acid is 2 phosphono-butane 1,2,4 tricarboxylic acid.
It is preferable if the level of organo monophosphonic acids is from 0.1 to 5 wt %, more preferably 0.5 to 3 wt %, most preferably 0.5 to 2 wt. % of the total composition.
Builder Material
The compositions of the invention comprise as a water-soluble acid builder sodium citrate.
It is preferable if sodium citrate is present at a level of at least 15 wt % of the total formulation, more preferably at a level greater than 20 wt %, most preferably at a level greater than 30 Wt %. a level greater than 20 wt %, most preferably at a level greater than 30 Wt %.
It is desirable if a second builder is present. Preferred builders include sodium carbonate (with or without calcite seeds), potassium carbonate, sodium and potassium bicarbonates. Sodium and potassium bicarbonates are especially preferred, most especially sodium bicarbonate.
It is preferred if the weight ratio of citrate builder to builder is at least 1:1, preferably between 1:1 and 4:3.
Further soluble detergency builder salts that can be used with the present invention are poly-valent inorganic and poly-valent organic builders or mixtures thereof. Non-limiting examples of suitable water-soluble, inorganic alkaline detergency builder salts include borates, phosphates, polyphosphates, and tripolyphosphates. Specific examples of such salts include the sodium and potassium tetraborates, tripolyphosphates, orthophosphates and hexametaphosphates. However it is preferable if the detergent formulation is free or only has low levels (5% or less) of builder salts which precipitate during the wash in the presence of calcium.
Other additional detergency builders include organic alkaline compounds such as water-soluble amino polyacetates, e.g. sodium and potassium ethylenediamine tetraacetates, nitrilotriacetates and N-(2-hydroxyethyl) nitrilodiacetates; water-soluble salts of phytic acid, e.g. sodium and potassium phytates; water-soluble polyphosphonates, including sodium, potassium and lithium salts of ethane-1-hydroxy-1,1-diphosphonic acid; sodium, potassium and lithium salts of methylenediphosphonic acid and the like.
It is to be understood that, while the alkali metal salts of the foregoing inorganic and organic poly-valent anionic builder salts are preferred for use herein from an economic standpoint, the ammonium, alkanolammonium, e.g. triethanol-ammonium, diethanolammonium, and the like, water-soluble salts of any of the foregoing builder anions are useful herein.
Preferred builders for use in the invention are sodium citrate and sodium bicarbonate and mixtures thereof. Alternatively, the potassium salts of these acids may be used.
Preferably, the amount of total builders in the composition is from 30 to 80% by weight, more preferably from 40 to 70% by weight.
Silica Material
Suitable forms of silica include amorphous silica, such as precipitated silica, pyrogenic silica and silica gels, such as hydrogels, xerogels and aerogels, or the pure crystal forms quartz, tridymite or crystobalite, but the amorphous forms of silica are preferred. Suitable silicas may readily be obtained commercially. They are sold, for example under the Registered Trade Name Gasil 200 (ex Crosfield, UK).
Preferably, the silica is in the product in such a form that it can dissolve when added to the wash liquor. Therefore, addition of silica by way of addition anti-foam particles of silica and silicone oil is not preferred.
The particle size of the silica material of the present invention may be of importance, especially as it is believed that any silica material that remains undissolved during the washing process, may deposit on the glass at a later stage. Therefore, it is preferred that silica material are used that have a particle size (as determined with a Malvern Laser, i.e. “aggregated” particles size) of at most 40 &mgr;m, more preferably at most 30 &mgr;m, most preferably at most 20 &mgr;m provides better results in the wash. In view of incorporation in a cleaning composition, it is preferred that the particle size of the silica material is at least 1 &mgr;m, more preferably at least 2 &mgr;m, most preferably at least 5 &mgr;m.
Preferably the primarily particle size of the silica is in general less than about 30 nm, in particular less than about 25 nm. Preferably, elementary particles sizes are less than 20 nm or even 10 nm. There is no critical lower limit of the elementary particle size; the lower limit is governed by other factors such as the manner of manufacture, etc. In general, commercial available silicas have elementary particle sizes of 1 nm or more.
Preferably, the silica material is present in the wash liquor at a level of at least 2.5×10
−4
%, more preferably at least 12.5×10
−4
%, most preferably at least 2.5×10
−3
% by weight of the wash liquor and preferably at most 1×10
−1
%, more preferably at most 8×10
−2
%, most preferably at most 5×10
−2
% by weight of the wash liquor.
Preferably, the level of dissolved silica material in the wash liquor is at least 80 ppm, more preferably at least 100 ppm, most preferably at least 120 ppm and preferably at most 1,000 ppm. It is noted that for the silica material to be effective, the lower level of dissolved silica material depends on the pH value, i.e. thus at pH 6.5, the level is preferably at least 100 ppm; at pH 7.0 preferably at least 110 ppm; at pH 7.5 preferably at least 120 ppm; at pH 9.5 preferably at least 200 ppm; at pH 10 preferably at least 300 ppm; at pH 10.5 preferably at least 400 ppm.
Preferably, the silica material is present in the cleaning composition at a level of at least 0.1%, more preferably at least 0.5%, most preferably at least 1% by weight of the cleaning composition and preferably at most 10%, more preferably at most 8%, most preferably at most 5% by weight of the cleaning composition.
Silicates
The composition optionally comprises alkali metal silicates. The alkali metal may provide pH adjusting capability and protection against corrosion of metals and against attack on dishware, including fine china and glassware benefits. When silicates are present, the SiO
2
level should be from 1% to 25%, preferably f

Affiliated with

Also associated with

Rating

Machine dish wash compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Machine dish wash compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Machine dish wash compositions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2569379