DE2142055A1 - - Google Patents

Description

47 805

Applicant: Economics Laboratory, Inc., Osborn Building, St. Paul , Minnesota 55102, USA

Machine dishwashing detergent

Washing agents "or detergents for machine dishwashing represent a generally recognized class of detergent compositions. Machine detergents Dishwashing is a mixture of ingredients which, in combination, have the task of emulsifying residues of foodstuffs and to remove, to inhibit the foaming caused by certain food residues, the wetting of To promote eating utensils and in this way to keep or prevent visually recognizable jflecking as low as possible, Remove picks - such as those caused by coffee and tea the build-up of dirt films on the surfaces of To "prevent eating utensils, to reduce or eliminate the cloudy or tarnishing of eating utensils, and to reduce bacteria." destroy. In addition, detergents for automatic dishwashing must have these properties without the surfaces to etch or corrode or otherwise damage tableware and cutlery.

Dishwashing detergents for machine washing are often strong alkaline (pH value of more than 10.0 and often more than 12.5 in concentrations of 1 percent by weight in water). Frequently These detergents for automatic dishwashing are seen by mixing or combining in another way of alkaline Detergent salts and alkali salts formed from condensed phosphates, Ohlorabspaltenae agents and low-foaming agents

or non-foaming organic surfactants (for example nonionic surface-active agents) v / ground often optionally and preferably added to these mixtures.

In recent years there has been increased attention to the Problems of environmental pollution (e.g. the water supply chmut sung). Phosphates have been identified as a factor which contributes to water pollution (for example by promoting the algae turn) and there have been considerable Efforts are directed towards the machine-based training G dishwashers use condensed alkali phosphates to replace all or at least a significant part with chemicals that are ecologically acceptable. Among the numerous Compounds that have been tested as a means of replacing condensed alkali metal phosphates (especially for replacing of sodium tripolyphosphate), there are very few compounds which have led to ■ satisfactory results. Many chemicals lack the desired cleaning power. Other chemicals lack a threshold effect (threshold effect), that is, the ability to be present in hard form To "bind metal ions in a complex way beyond their stoichiometric presence (in contrast to sodium tripolyphosphate, that has this ability). Still other agents cause foaming difficulties and others are ecological as or more undesirable than the condensed alkali metal phosphates.

Among the many chemical compounds that have been tested for use in place of sodium tripolyphosphate, nitrilotriacetic acid appears to be one of the most promising contenders. An adverse effect of nitrilotriacetic acid (often called "ITTA"), however, is their tendency to use chlorine in the detergent solutions used for mechanical purposes Dishwashing to destabilize. Other disadvantages currently exhibited by nitrilotriacetic acid include the. high price, the lack of general accessibility and the lack of a wave effect «- 3 -

209812/151 1

2U2055

The invention is based on the discovery that metal salts of citric acid, e.g. sodium citrate, are effective agents for partial replacement of condensed. Alkali phosphates are in detergents for machine dishwashing. The usage of citrates in combination with reduced proportions of condensed alkali metal phosphates (for example reduced Proportions of sodium tripolyphocphate) leads to results in Dishwashing that are technically acceptable by today's industrial and household standards. By maintaining a certain amount of condensed alkali phosphate in the dishwashing detergent can provide effective complex binding and deflocculation of metal ions in hard water. In addition, the citrates are very stable in the presence of chlorine-releasing agents (e.g. potassium dichloroisocyanurate).

The detergents according to the invention for machine dishwashing can be used as solid detergents or as liquid detergents, can be formulated in a single package or in multiple packages.

Solid or dry detergents can be prepared by mixing the various detergent-forming ingredients into one powdered or granular product can be formed, or they can be agglomerated, pelletized, or the like be shaped.

Liquid detergents in several packages are detergents for machine dishwashing, .which come in the form of two or a plurality of separate liquid components are formed, each component being packaged separately. When washing dishes the separated components are transferred to the separate containers through a suitable distribution device inserted the dishwasher tank.

2098T2 / 1511

2U2055

While the invention can be used in any of these various ways' used or by machine dishwashing detergents they are embodied; However, the greatest advantages are with the production of solid detergent compositions and in one Pack present liquid'waschmittelmassen connected. Of these is the manufacture and use of solid detergents of particular importance for machine dishwashing.

The detergent compositions according to the invention for machine dishwashing usually contain at least one alkaline detergent salt, at least one salt-like "phosphate", at least a citrate and optionally a chlorine releasing agent and various surface active agents. If desired, can the detergent compositions according to the invention also have other constituents be admitted.

The pH of these machine dishwashing detergents is at least 10.0 at a concentration of 1 percent by weight in water. pH values greater than 11.0 are special desirable when used for washing dishes in institutions, while pH values from 10.0 to 11.0, in particular 10.0 up to 10.5 are desirable for washing dishes in the household.

Alkali salts of detergents or alkali salts of detergent builders or detergent additives, as they sometimes do (which are different from the condensed alkali phosphates) are well known in the detergent industry. These include compounds such as di- and trisodium orthophosphate, Sodium carbonate, sodium bicarbonate, sodium silicate, sodium metasilicate, Sodium borate, caustic soda (sodium hydroxide), caustic potash (potassium hydroxide), and the like.

The total combined amount of these detergent salts is generally, but not always, less than 80 percent by weight of the total dishwashing detergent mixture (based on dry substance). In the most common case, the whole lies

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2H2055

Proportion of these detergent salts in the range of 2 Ms 70 percent by weight, "on the same basis.

Alkali salts of condensed phosphoric acids are also well known in the detergent industry. To these condensed Phosphates include letra sodium pyrophosphate, potassium pyrophosphate, Sodium tripolyphosphate and the like. When used in the hates according to the invention "is the proportion of the condensed alkali metal phosphate in the detergent mixtures is less than 30 percent by weight, "based on Dry ingredients. Usually the level of condensed alkali metal phosphate used in these mixtures is. 2 "to 20 percent by weight, in particular and for example 2 to 10 percent by weight, based on the same basis.

Any water-soluble metal salt of citric acid can be used for the purposes of the invention. However, not all salts fulfill the intended purpose with the same effectiveness; for this reason, alkali metal salts are preferred. A particularly preferred compound is sodium nitrate. Commercially available sodium citrate (more precisely referred to as Irina triumei trat) is available in the form of white crystals or as a granular powder. Ss is odorless, stable in the air and has a pleasant salty taste. Every molecule of Trinatriuincitra.ts loses two molecules of water when heated to 1150 ° G. Commercially available potassium citrate is also available in the form of white crystals or as a powder. It is usually available in the monohydrate form (as opposed to sodium citrate, which is a dihydrate).

The proportion of citrate used for the purposes of the invention is more than 5 weight percent, and is generally within the 'range of from 5 to 60 weight percent on a dry basis (in terms of irinatriumoitrat) _β The water of hydration can be considered as a cable of the salt ₀ lasIbesoma © e @ is the proportion of nitrate used (kyfeatisrt odor not hydrated) 5 to 40 percent by weight, for example

-SI

2U2055

10 to 30 percent by weight on the same basis.

If necessary, mixtures of citrates can be used Even if this is not preferred, the citrate can be in situ for example by adding citric acid and sodium or Potassium hydroxide are formed. The use of a pre-formed alkali metal citrate or a mixture such citrates are particularly preferred.

The various suitable chlorine-releasing agents include chlorinated trisodium phosphate, potassium and sodium di-chloroisocyanurate, Triehlormelamin, Chloramine T, alkali metal and alkaline earth metal hypochlorites (e.g. sodium hypochlorite), Mono-, di- and ^ trichloroisocyanuric acid, bichlorodimethylhydantoin, Cocrystals of trichloroisocyanuric acid and salts of dichloroisocyanuric acid (for example the Sodium or potassium salt).

To other Beatand parts or additives that the invention Laundry detergents added to machine dishwashing include low-foaming and non-foaming surface-active agents, such as various polyoxyalkylene polymers, Bases such as sodium and potassium hydroxide, fillers, corrosion inhibitors, dyes and the like.

The invention is further illustrated by the following specific examples. Unless otherwise stated, all parts and percentages mean parts by weight and percent by weight *

example 1

This example illustrates the preparation of a solid or dry dishwashing detergent according to the invention. The following dry ingredients are mixed with one another in the specified proportions. The pH of the resulting mixture is above 10.0.

209812 / 1S11

- 7 - 2U2055 mechanical in part of the of the solution ■ f
component Share (£) listed as 10.0. Water or dissolved in all of the water. After that it becomes EOH Sodium citrate dihydrate 25.0 Share ($) added to neutralize the citric acid (in situ ITodium tripolyphosphate (anhydrous) 5.1 10.0 to form a citrate). After cooling down caustic soda (anhydrous) 21.0 5.0 the other ingredients added. ITodium metasilicate (anhydrous) 25.0 55.0 ITa trium carbona t 21.9 1.5 ITa tr iumdichlor i s ocyanur a t 2.0 28.5 100.0 1o 100.0 Jt Example 2 ' The specified ingredients are in the following manner This example illustrates how to make one in one mixed together. Citric acid will single pack of liquid detergent concentrate or detergent concentrates for Dishwashers that have a pH greater than component Citric acid Tetrapotassium pyrophosphate liquid KOH (45 5 ^). ITaOCl water

209812/1511

Claims (9)

2U2055 claims 1. Detergent for automatic dishwashing, which has a pH of more than 10.0 and contains at least one condensed s _# alkali metal phosphate and at least one detergent builder salt, characterized by the content of a metal salt of citric acid. 2. Detergent according to Claim 1, characterized in that it contains less than 30 percent by weight of the condensed alkali metal phosphate and at least 5 percent by weight of the metal salt of citric acid, based on the dry detergent, contains. 3. Detergent according to claim 1 or 2, characterized in that it is in solid form and a dry, chlorine-releasing agent Contains bleach. 4. Detergent according to claim 3, characterized in that the bleaching agent is a chloroisocyanuric acid or a salt of which is. 5. Detergent according to claim 1 or 2, characterized in that it is in the form of a liquid concentrate and contains a chlorine-releasing agent. 6. Detergent according to claim 4, characterized in that it contains 2 to 10 percent by weight of the condensed alkali metal phosphate and contains from 10 to 30 percent by weight of the metal salt of citric acid. 7. A method for producing a detergent for automatic dishwashing, which has a pH of at least 10.0, made of at least one condensed alkali metal phosphate and at least one »vanishing agent salt 209812/1511 _ 9 - as components, characterized in that a part of the condensed alkali metal phosphate is replaced by a metal salt of citric acid «, 8.'Verfahren according to claim 7 _S characterized gekennzelehnet that, based on the dry detergent mixture »less than 30 percent by weight of the condensed alkali metal phosphate and at least 5 percent by weight of the metal salt of the nitro ~ \ nenic acid are added _o · 9. The method according to claim 7 or 8 _P, characterized in that the detergent is produced in solid form and that a chlorine-containing dry bleach is added ο 10 "Method according to claim 9 _S, characterized in that a chloroisocyanuric acid or a salt thereof is used as the bleaching agent 11 "Process according to claim 7 or S ₅ , characterized in that the detergent is produced in the form of a liquid consume and that a chlorine-releasing agent is added ο 12 · The method of claim 7 characterized Ms 11 _{9 P} that the salt of citric acid used is formed in situ ο 13o A method according .Anspruch 7 ms 12, characterized in that marked ä®m detergent 2 to 10 weight percent of the kondensiort & k AlkaliphoBphats and 10 to 30 weight percent ά <= 8 Ifetallsalges of citric acid added