CA1168948A - Detergent compositions stable to chlorine separation, and agents for producing same - Google Patents

Abstract

CANADIAN PATENT APPLICATION

OF

KRISTER HOLMBERG and INGVAR NILSSON

FOR

DETERGENT COMPOSITIONS STABLE TO CHLORINE SEPARATION, AND AGENTS FOR PRODUCING SAME

Abstract of the Disclosure:

Detergent compositions stable to chlorine sepa-ration are described, which as main constituents contain alkali metal phosphate, alkali metal silicate, a tenside and granulate chlorinated triazine trione, the granules of the chlorinated triazine trione being coated with a thin layer of a hydrophobic substance. The surface-treated chlorinated triazine trione which constitutes an agent for producing the composition, is also described as is the use of the composition as a machine dish washing detergent or industrial detergent.

Description

9 ~ ~

DETERGENT COMPOSITIONS_STABLE TO_CHLORI~E SEPARAT~L
AND AGENTS FOR PRODUCING SAME

This invention relates to detergent compositions stable to chlorine separation for use as machine dish washing de-tergents or industrial detergents, and to agents for pro-ducing said compositions.
Machine dish washing detergent compositions for exam-ple consist mainly of - alkali metal phosphate - alkali metal silicate - tenside - organic chlorine compound.
The alkali metal phosphate, usually sodium tripoly-phosphate, primarily serves as complexing agent for cal-cium and magnesium ions.
The alkali metal silicate normally is a sodium sili-cate having a molar ratio SiO2 : Na2O of 3.50 to 0.75.Usually,use is made of so-called sodium metasilicate, which implies that said ratio lies about 1. The purpose of the silicate is to provide a high pH, which is needed int.al. for hydrolysis of edible fat rests, and to have a corrosion preventing effect.
The sodium metasilicate may be either practically anhydrous or be present as a hydrate with crystal bound water. The commercially most usual hydrate is the crystalform called pentahydrate. This product is usually writtenas SiO2 . Na2O 5H2O, but actually is a tetrahydrate of the salt Na2H2SiO4. This crystal form is hereinafter called "pentahydrate".
The pentahydrate offers several advantages over the anhydrous sodium metasilicate in machine dish washing detergent compositions, int.al. because it is more readily soluble and considerably cheaper. The introduc-tion of water into a machine dish washing detergent composition in powder for~ however, as experience has ~. 1.,.~, 1 1~89~8 shown, entails problems regarding the stability of the organic chlorine compounds. These readily hydrolyzed compounds in fact give off chlorine gas in a moist environment, which amounts to a considerable technical problem. For these reasons, use is preferably made of anhydrous sodium metasilicate in said products.
The tenside usually is a low-foaming non-ionic ten-side, preferably a block polymer of ethylene and pro-pylene oxide. Its task is to contribute to wetting and emulisification simultaneously as it shall have an antifoaming effect on for example proteins.
The organic chlorine compound or chlorine carrier functions as an oxidative bleaching agent which has the task of attacking deposits of int.al. coffee, tea and fruit juices. The economically most favourable chlorine carrier is trichloroisocyanuric acid, but it is very instable and gives off chlorine too easily to permit being used in practice. Salts of dichloroisocyanuric acid are therefore used in most cases and the sodium salt has, primarily for economical reasons, been most widely utilized.
Apart from the above-mentioned main components, machine dish washing detergents often also contain varying quantities of alkalimetal carbonates and bi-carbonates, corrosion inhibitors, dyes and perfume.
What has been said above about machine dish washingdetergents is also true, in a~plicable parts,to indus-trial detergent compositions generally.
There have been made great efforts to stabilize the organic chlorine compounds in detergent compositions and thereby to reduce the problem of a premature chlorine gas development. It has been tried, by addition of re-ducing agents (cf. German Patent 1,111,198) or by adjust-ment of pH with the aid of a combination of boron oxide and soda (cf. French Patent 1,537,311) to reduce the tendency of chlorine separation in alkali salts of di chloroisocyanuric acid. There is also described a method 4~7 3_ of adding pararin oil to compositions based on these ch]orine compounds (cf. U.S. Patent 3,390 092). Tri-cllloroisocyanuric acid also has been s-tabi]ized for in-s-~ance by mfians of an oleiin having a car}on--carbon double bond one carbon a,o~n of said double bord being tertiary (cf. Bl-itisll Patent ~8,397). Co~lon to all of these metl^~oc's is t]-~at even though they imply a certain improve-ment as to stability to chlorine separation, the result is far from sa-tisfactory. With the use of sodium metasilicate ]0 pentahydrate in detergellts an uncontrolled discharge of chlorine gas therefore still is a production-technical problem for the industries producing the detergents and also an important practical problem for the consumer because of chlorine smell and lower bleaching effects.
It has now been fourld that the tendency of chlorine separation in organic chlorine compounds can be reduced and a surprisingly good result be reached by surface-treating said chlorine compounds in granular form with a hydrophobic substance. ~lowever, a prerequisite is that the chlorine compounds ar~ p-esent in granulated form, with a particle size of about 0.5 to 5 mm. Pulverulent compounds cannot be surface-tr2ated in this way since caking of the product will result from such a treatment~ Machine dish washing detergents and :industrial detergents based on surface-treated organic chlorine compounds show a high degree of stability to chlorine separation. Surface-treated trichloroisocyanuric acid also gives acceptable results when used in machine dish washing detergents and industrial detergents.
A considerable reduction of the chlorine losses is obtained not only at the storing of the finished machine dish washing detergent but also in the production thereof when use is made of a chlorine compound surface-treated in accordance with the present invention.
This invention thus relates to a detergent composition comprising 25-60~ by weight alkali netal phosphate, 20-70~

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,~

by weight alkali metal silicate, 0.5-3~ by weight a ten-side, 1-10% by weight a chlorinated triazine trione of formula (I) X

O ~\~0 ~`C C (I) N

\C

o wherein X is Cl, Na or K, or when X is Na, the dihydrate thereof, and opti.onally conven-tional additives. Said composition is characterized in that the chlorinated triazine trione of formule (I) is in the Eorm of granules coated with a thin hydrophobic layer of a diester of phthalic acid or adipinic acid with an alcohol having 4-18 carbon atoms in an amount of 3-9% by weight, calculated on the amount of chlorinated triazine trione of formula (I).
The invention further relates to an agent for pro-ducing the detergent composition, said agent being character-ized in that it consists of granules of chlorinated triazine trione of formuLa (I) X

~C~ ~
N ~ ~ (I) Cl ~ Cl wherein X is CL, Na or K, or the dihydrate of the triazine trione of formula (I) when X is Na, said granules being coated with a thin hydrophobic layer of a diester 1 1689~

of phthalic acid or adipinic acidwithan alcohol hav-ing 4-18 carbon atoms in an amount of 3-9~ by weight, calculated on the amount of the chlorinated triazine trione of formula (I).
Different embodiments of the composition according to the invention comprise a machine dish washing de-tergent composition and an industrial detergent compo-sition, respectively.
The surface-treatment of the chlorinated triazine trione is preferably performed such that the hydrophobic substance in liquid form or dissolved in a readily volatile solvent is added by portions under some kind of agitation to the granulate chlorinated triazine trione which is thereby coated with a thin film of hydrophobic material effectively protecting the labile chlorine compound from contact with water.
The hydrophobic film-forming substances utilized in the surface-treatment are diesters of certain car-boxylic acids, particularly phthalic acid or adipinic acid, which surprisingly have proved to yield excel-lent results.
The diesters preferably utiliæed in the invention are diesters of phthalic acid or adipinic acid with an alcohol having 4-18 carbon atoms, preferably a straight or branched alcohol having 6-12 carbon atoms.
The following diesters have proved to be particularly useful:
phthalate 610 di-(2-ethyl hexyl)phthalate diisodecyl phthalate di-(2-ethyl hexyl)adipate diisodecyl adipate ~phthalate 610 is the trade nameof a fraction of di-esters of phthalic acid and alcohols having 6-10 car-bon atoms.

1 ~689~a The most important physical property required in the diesters utilized for the sur~ace-treatment is that they shall be sufficiently water-repellent in order that also a thin layer of the diester shall provide S a fully satisfactory moisture protection for the en-closed chlorine compound. Further, it is advantageous if the diester is liquid at room temperature or has a melting point not too far above said temperature, preferably below 70C. ~se can also be made of diesters having a higher melting point, in which case these are first dissolved in a volatile solvent whereupon the surface-treatment proper is performed and the solvent is finally driven off by heating of the granulate sur-face-treated product.
Naturally,it is also of great importance for the diesters to have a good adhesion to the granulate chlo-rine compound.
The chlorinated triazine compounds of formula I
comprise Na-dichloroisocyanurate Na-dichloroisocyanurate dihydrate K-dichloroisocyanurate ~richloroisocyanuric acid.
A complex between K-dichlorocyanurate and trichloro-isocyanuric acid is also well suited for use with thepresent invention.
The surface-treatment provides an effect already at astonishingly small amounts of the hydrophobic sub-stance. For most of the substances tested a content of 3-9% by weight calculated on the chlorinated triazine trione has proved to be sufficient. In most cases it has even been found disadvantageous to exceed that amount as this results in the surface-treated product becoming sticky and having a tendency of aggregating.
A machinedishwashing detergent composition being an embodiment of the present invention has the ~ollowing constitution as regards its essential components (the ~ 168~

percentages are percentages by weight):
- alkalimetal phosphate in an amount of 25-60%, prefer-ably 40-50~, - alkalimetal silicate in an amount of 30-70%, preferably 40-60%, molar ratio SiO2 : Na2O (K2O) of 3.50 - 0.75, preferably about 1, and a water content of 0 - 60%, preferably 0 - 5% or 35 - 45%, - a low foaming non-ionic type tenside in an amount of 0.5 - 3%, preferably 1 - 2%, - a chlorinated triazine trione of formula (I~, sur-face-treated with a hydrophobic substance in an amount of 1 - 5%, preferably 1 - 3 % (the amount of hydro-phobic substance is 3 - 9 %, preferably 5 - 8 %, cal-culated on the chlorinated triazine trione), - conventional additives in an amount of 0 - 40%, pre-ferably 0 - 20 %.
An industrial detergent composition ~eing another embodiment of the present invention has the following constitution (the percentages are percentages by wei~ht):
- alkalimetal phosphate in an amount of 25 - 60 %, pre-ferably 40 - 50 ~, - alkalimetal silicate in an amount of 20 - 70 %, pre-ferably 25 - 45 ~, molar ratio SiO2 : Na2O(K2O) of 3.50 - 0.75, preferably about 1, and a water content of 0 - 60 %, preferably 0 - 5 % or 35 - 45 %, - alkalimetal hydroxide in an amount of 0 - 30 %, pre-ferably 10 - 20~, - a low foaming non-ionic type tenside in an amount of 0.5 - 3 %~ preferably 1 - 2 %, - a chlorinated triazine trione of fo~lula (I), sur-face-treated with a hydrophobic substance, in an amount of 1 - 10 %, preferably 2 - 5 ~ (the amount of hydro-phobic substance is 3 - 9 %, preferably 5 - 8 %, cal-culated on the chlorinated triazine trione), - conventional additives in an amount of 0 - 40 %, pre-ferably 0 - 20 %.
As will appear from Example 3 below, it is possible 1 1~8~8 to produce with the aid of the above-described surface-treating method a detergent composition based on sodium metasilicate pentahydrate wnicn is at least e-lually stable to chlorine separation as a corres~onding proauct based on anhydrous sodium metasilicate and a non-treated or-ganic chlorine compound. The amount stated of hydro-phobic material for the surface treatment, usually 5 - 8 %
of the amount of organic chlorine compound, usually constitutes but 0.05 - 0.25 % of the total detergent composition. The additional cost of said raw product and of the extra operation the surface treatment in-volves, is small compared with the savings in raw ma-terial costs realized by turning from anhydrous meta-silicate to the pentahydrate thereof.
lS Especially astonishing is that very good results are also obtained with trichloroisocyanuric acid (see Example 2).
Another advantage gained by the surface-treating method indicated thus resides in the possibility of being able to replace the anhydrous metasilicate in detergents with the corresponding pentahydrate, retaining the stability to chlorine separation of t~e detergents.
An alternative application of the surface-treating method is to provide compositions based on anhydrous metasilicate and a surface-treated organic chlorine compound, said compositions being extremely stable to chlorine separation However, such a formulation will be relatively exl~ensive and may probably be used only for special purposes.
The following Examples are meant to illustrate the invention without restricting it in any way.

The effect of a surface-treatment of Na-dichloro-isocyanurate for machine dish washing detergents stored at 30C/85% relative moisture was examined. The samples were stored in board cartons treated with polyethylene.
The chlorine content was determined by titration accord-1 16~948 ing to the iodine-thiosulphate method.
The following machine dish washing detergent com-position was used in the tests:
sodium tripolyphosphate 40.0 parts 5 sodium metasilicate pentahydrate 50.0 "
non-ionic tenside (block polymer of ethylene and propylene oxide) 2.0 "
surface-treated sodium dichloro-isocyanurate 2.0 "
10 water 6.0 "
A great many different substances were tested as surface-treating agents. The substances most useful in practice are indicated in Table 1.
The surface-treating agent was added by portions under vigorous agitation to the granulate chlorine com-pound. After finished addition the agitation was con-tinued for a further 2 - 3 minutes. Low viscous sub-stances were added at room temperature whereas high viscous substances as well as solid compounds were first heated to suitable viscosity. The surface treat-ing agent was added in an amount of 7 %, and in some cases also 5 %, calculated on the chlorine compound.
A reference test was made, in which the surface-treat-ing agent was replaced by soda which is totally inert in this connection.
The chlorine content of the various dish washing detergent compositions which thus differ only with re-gard to the surface-treatment of sodium dichloroisocya-nurate, was determined as a function of the storage time.
The results of the tests are given in Table 1.

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~ S rl rl ~ r1 rl ~~ 0 U~ ~4 4 a 4 4 a ~; ~c The effect of a surface-treatment of trichloro-isocyanuric acid for machine dish washing detergents stored at 30/85 % relative moisture was examined. The samples were stored in board cartons treated with poly-ethylene. The chlorine content was determined by ti-tration according to the iodine-thiosulphate method.
The following machine dish washing detergent com-position was used in the tests:
10 sodium tripolyphosphate 40.6 parts sodium metasilicate pentahydrate 50.0 "
non-ionic tenside 2.0 "
surface-treated trichloroisocyanuric acid 1.4 "
water 6.0 "
A great many different substances were tested as surface-treating agents. The substances most useful in practice are indicated in Table 2.
The surface-treating agent was added by portions under vigorous agitation to the granulate chlorine compound. After finished addition agitation was con-tinued for a further 2 - 3 minutes. Low viscous sub-stances were hereby added at room temperature whereas high viscous substances as well as solid compounds were first heated to a suitable viscosity. The surface-treating agent was added in an ~,~ount of 6 %, calculat-ed on the chlorine compound. A reference test was made in which the surface-treating agent had been replaced by soda which is entirely inert in this con-nection.
The chlorine content of the different machine dish washing detergent compositions which thus differ only with regard to the surface-~reatment of trichloro-isocyanuric acid, was determined as a function of the storage time.
The results of the tests are indicated in Table 2.

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EX~PLE 3 The effect of the surface-treatment of the organic chlorine compound for machine dish washing detergents based on anhydrous metasilicate and the pentahydrate S thereof, respectively, was tested and compared with regard to stability to chiorine sep~ration. Wse was maae as sur-face-treating agent of di-(2-ethyl hexyl)phthalate in an amount of 7 ~ calculated on the organic chlorine compound. The following formulations were usea:
A B
sodiumtripolyphosphat 40.0 parts 40.0 parts sodium metasilicate, anhydrous - 40.0 1 sodium metasilicate, 5 pentahydrate 50.0 "
non-ionic tenside (block polymer of ethylene and propylene oxide) 2.0 " 2.0 "
~o surface-treated sodium dichloroisocyanurate2.0 " 2.0 "
water 6.0 " 10.0 "
soda - 6.0 "

Reference tests were made for the two formulations (reference A and reference B, respectively), in which the di-(2-ethyl hexyl)-phthalate was replaced by soda.
The procedure applied at the surface-treatment like the execution and evaluation of the tests were analogous with those in Example 1.
The results of the examination will appear fror, Table 3. As is evident, the surface treatment had a positive effect in both cases. It also appears from the Table that a machine dish washing detergent based on metasilicate pentahydrate and surface-treated chlorine compound (R) will be at least equally stable to chlo-rine separa~ion as a ae~ergent based on anhydrous rneta-silicate and untreated chlorine cornpound (B).

1 ~6~9~8 Residual chlorine (in ~) Formulation Storage time (months) A 1.16 0.94 0.92 0.90 reference A1.15 0.86 0.72 0.48 B 1.25 1.18 1.12 1.08 reference B1.25 1.05 0.93 0.81 The effect of a surface-treatment of sodium dichlo-roisocyanurate for detergents stored at 30C/85 ~ re-lative moisture was examined. Tne sa,~ples are stored in board cartons treated with polyethylene. The chlorine content was determined by titration according to the iodine-thiosulphate method.
The following detergent composition was used in the tests:
10 sodium tripolyphosphate 45 parts sodium metasilicate pentahydrate25 "
sodium hydroxide 15 "
non-ionic tenside 2 "
surface-treated sodium dichloroisocyanurate 4 "
lS soda 9 "
A great many different substances were tested as surface-treating agents. The substances most useful in practice are indicated in Table 2.
The surface-treating agent was added by portions under vigorous agitation to the granulate chlorine compound. After finished addition agitation was con-tinued for a further 2 - 3 minutes. Low viscous sub-stances were hereby added at room temperature whereas high viscous substances as well as solid compounds were first heated to a suitable viscosity. Tne surface treating agent was added in an amount C)L 7 ~, calculatea on the chlorine compound. A reference te~t W.3, r.iade, in whicn the surface treating agent was replaced by soda which is entirely inert in this connection.
The chlorine content of the different detergent com-positions which thus differed only with regard to the sur~
face-treatment of sodium dichloroisocyanurate, was deter-mined as a function of the storage time.
The results of the tests are indicated in Table 4.

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ll689~a 18.6 kg of granulate sodium dichloroisocyanurate were charged into a Lodiger mixer of 50 1. Under vigorous agitation 1.4 kg of di-(2-ethyl-hexyl)phthalate was added through a fine nozzle. The time of supply amounted to 3 - 5 minutes. After finished supply agitation was continued for a further few minutes, whereupon the mixer was emptied.

Claims (8)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A detergent composition comprising 25-60%
by weight alkali metal phosphate, 20-70% by weight alkali metal silicate, 0.5-3% by weight a tenside, 1-10% by weight a chlorinated triazine trione of the formula (I) wherein X is C1, Na or K, or when X is Na, the dihydrate thereof, and optionally conventional additives, character-ized in that the chlorinated triazine trione of formula (I) has the form of granules coated with a thin hydro-phobic layer of a diester of phthalic acid or adipinic acid with an alcohol having 4 - 18 carbon atoms in an amount of 3-9% by weight, calculated on the amount of the chlorinated triazine trione of formula (I).

2. The composition of claim 1, characterized in that the alcohol is a straight or branched alcohol having 6 - 12 carbon atoms.

3. The composition of claim 1, characterized in that the hydrophobic layer comprises phthalate 610, di-(2-ethyl-hexyl) phthalate, diisodecyl phthalate di-(2-ethyl-hexyl) adipate and/or diisodecyl adipate.

4. The composition of one or more of claims 1-3, characterized in that for use as machine dish washing detergent the composition comprises 25-60% by weight of alkali metal phosphate 30-70% by weight of alkali metal silicate 0.5-3% by weight of tenside 1-5% by weight of chlorinated triazine trione 3-9% by weight of diester, calculated on the amount of chlorinated triazine trione 0-4 0% by weight of conventional additives.

5. The composition of claims 1, 2 or 3 characterized in that for use as an industrial detergent the composition comprises 25-60% by weight of alkali metal phosphate 20-70% by weight of alkali metal silicate 0-30% by weight of alkali metal hydroxide 0.5-3% by weight of tenside 1-10% by weight of chlorinated triazine trione 3-9% by weight of diester, calculated on the amount of chlorinated triazine trione 0-4 0% by weight of conventional additives.

6. An agent for producing the detergent composition, characterized in that the agent comprises granules of chlorinated triazine trione of the formula wherein X is C1, Na or K, or the dihydrate of the triazine trione of formula (I) when X is Na, said granules being coated with a thin hydrophobic layer of a diester of phthalic acid or adipinic acid with an alcohol hav-ing 4-18 carbon atoms in an amount of 3-9% by weight, calculated on the amount of the chlorinated triazine trione of formula (I).

7. The agent of claim 6, characterized in that the alcohol is a straight or branched alcohol having 6-12 carbon atoms.

8. The agent of claim 6, characterized in that the hydrophobic layer comprises phthalate 610, di-(2-ethyl hexyl) phthalate, diisodecylphthalate, di-(2-ethyl hexyl) adipate and/or diisodecyladipate.