DE2423466A1 - ENCAPSULATED FORMULATION OF AN ORGANIC PERSAID - Google Patents

Description

Dr. Michael Hann H / D (622)

63 Giessen 2423466

Ludwigstrasse 67

PPG Industries, Inc., Pittsburgh, Pennsylvania, USA ENCAPSULATED FORMULATION OF AN ORGANIC PERSIC ACID Priority: May 16, 1973 / USA / Serial No. 360 858

This application relates to a formulation of an organic peracid in the form of an encapsulated core. More specifically, the application is directed to encapsulated bleach formulations of an organic peracid.

Bleach formulations of encapsulated peracids are known. For example, in U.S. Patent 3,494,787, there is a dry composition described, which contains a core of perphthalic acid, which is converted into a hydrated water-soluble salt, the the water of hydration loses below 150 ° C, is encapsulated. This composition has proven to be progressive, as the coating protects the perphthalic acid from decomposition protects caused by alkaline materials commonly found in detergent formulations. In addition, this formulation has the advantage that it acts as a heat consumer acts, because at elevated temperatures it has its hydra-

409848/1041

release water and thereby detonate the peracid prevented. In addition, this known composition has proven to be a very effective bleaching agent in warm Water that dissolves quickly and easily in the warm water and thus its active oxygen quickly can share. However, it has been found to be disadvantageous that this composition is not as effective in cold water is because many organic peracids dissolve relatively slowly in cold water. This slow dissolution rate the composition is particularly disadvantageous in those areas where cold water of a temperature of 20 C or lower is a common washing medium. Part of the difficulty stems from the fact that the automatic Washing machines in their set program only for a limited period of time for the washing and bleaching stage provide. As a result, if the bleach dissolves too slowly, insufficient time may be available Stand in order to get in contact with the dirty laundry sufficient amounts of dissolved bleach and active Provide oxygen. A second undesirable feature of the slow dissolution of the peracid is that Local high concentrations of the bleaching agent can occur because of the solid particles in the folds of the textile material can become trapped, causing local over-whitening and the appearance of white spots comes with colored materials.

409848/1041

There is therefore a need to increase the speed of dissolution of organic peracids. In addition, the acid should be in a form in which it can counteract Materials that can cause their decomposition is protected. As the peracid in a bleach formulation is usually is combined with alkaline detergents and since alkaline detergents cause the decomposition of the peracid, It is an object of the invention to provide the peracid in a rapidly dissolving formulation which, however, avoids contact between the peracid and the detergents.

According to the invention, this object is achieved by a formulation an organic peracid dissolved in the form of an encapsulated core, the formulation being characterized is that the core is particles of a solid organic peracid mixed with particles of a dispersant contains, which is substantially more soluble in water than the organic peracid, the core in the essentially encapsulated in a water dispersible material is that, in the absence of water, it is capable of contact of the peracid with substances that cause its decomposition cause to avoid.

Among encapsulating materials dispersible in water are understood to mean those materials that are distributed in water by dissolution or in some other way.

409848/1041

Included in a preferred embodiment of the invention either the core or the encapsulation material has a hydrated salt, the water of hydration below 30 C, but releases at least part of its hydration water below the decomposition temperature of the peracid. Such hydrated salts are particularly useful which contain at least a portion of their water of hydration release below 150 ° C, preferably below 120 C. The hydrated salt should be present in a sufficient amount be that there is at least 0.1 part by weight of water of hydration per part by weight of organic peracid

Organic peracids containing more than 3 weight percent active oxygen are preferred in the invention. the Organic peracids can be aliphatic, alicyclic and aromatic peracids. Examples of such acids are Diperadipxnsäure, Diperazelaic acid, Cyclohexyldipercarboxylic acid, Cycloheptyldipercarboxylic acid, Cyclooctyldipercarboxylic acid, Perbenzoic acid, para-nitroperbenzoic acid and meta-chloroperbenzoic acid. Typical perphthalic acids are mono- and diperphthalic acid, Perisophthalic acid and perterephthalic acid, being among these Acids Diperisophthalic acid is preferred. The formulation after The present invention is particularly important when the peracid is only sparingly soluble in water, i.e. less than about 1% by weight and preferably less than about 1/2% by weight.

In the invention, the organic acid is used with a dispersant combined that is essentially better in water

409848/1041

is more soluble than the peracid. Advantageously be these two components mixed uniformly. The core then has the form of a matrix of peracid particles, in in which the particles of the dispersant are dispersed. Suitable dispersants are those compounds, those in water of 15 C at least 1 gram per 100 grams Are soluble in water. Those compounds are preferred, of which 2 to 200 grams per 100 grams of water at 15.degree dissolve and particularly preferably those compounds with a solubility of 4 to 200 grams per 100 grams of water at 15 ° C. The core of the formulation containing the peracid and dispersant can contain from about 1 to about 90 weight percent dispersant contain. 2 to 75%, in particular 5 to 60%, of dispersants are preferred in the core.

The core containing the peracid and the dispersant is encapsulated in a water-dispersible substance, which in the absence of free water prevents the core from coming into contact with substances capable of decomposition to bring about the peracid. As the encapsulation materials, hydrated salts such as they can be used with good effect in the aforementioned US Pat. No. 3,494,787. When such a hydrated salt is used to encapsulate the peracid nucleus is used, its water of hydration combines with that of the hydrated salt into the core and thereby gives the total amount of water of hydration present. In general, the total amount of water of hydration in the formulation including the Core and the encapsulation material at least 0.1 and in the

409848/1041

Usually more than 0.25 parts by weight to one part by weight of peracid, the total amount of hydration water can increase up to 5 parts by weight to 1 part by weight of peracid. Examples of hydrated salts that can be used both as an encapsulation material and as a dispersant in the core are the hydrates of sodium acetate, monobasic sodium phosphate, dibasic sodium phosphate, sodium sulfate, sodium potassium tartrate, acid sodium tartrate, magnesium acetate, magnesium ammonium sulfate, aluminum nitrate, aluminum sulfate. Potassium benzoate, magnesium sulfate, potassium magnesium sulfate and sodium aluminum sulfate. Other hydrated salts, which keep their water of hydration below 30 ⁰ C, but at least;
are also suitable.

Keep half of 30 C, but at least partially 150 C

Non-hydratable salts can be used as both dispersants and encapsulating materials. Suitable non-hydratable salts are, for example, potassium sulfate, acid potassium sulfate, potassium dihydrogen phosphate, acid potassium phthalate, sodium nitrate and acid ammonium sulfate. Normally, a non-hydratable salt is used in combination with a hydrated salt in order to have a composition that can give off hydratable water. The hydrated salt can be mixed with the non-hydratable salt either in the core or in the encapsulation. Alternatively, a non-hydrated salt can be combined with the organic peracid in the core _r and a hydrated salt used as a coating material.

409848/1041

• In another embodiment of the invention, a hydrated salt as a dispersant in the core and a non-hydrated salt used as an encapsulation material will. When a non-hydrated salt is used as the encapsulation material, a binder is usually used, which is able to form a gel on contact with water, combined with the salt. By using the binder a better cohesive coating is obtained than with the salt alone. Binders that are used with the encapsulation salt used can be mixed to give a better cohesive coating are e.g. Magnesium aluminum silicate, polyvinyl alcohol, soluble starch, hydroxypropyl cell silose, hydroxyethyl cellulose, polyvinyl pyrrolide c Casein, zein and agar-agar.

In another embodiment of the invention, the Peracid core with a water-dispersible organic Encapsulates material such as polyvinyl alcohol, soluble starch, gelatin or carboxymethyl cellulose. Such encapsulation is usually achieved by encapsulating the core particles with the organic material in a liquid state, such as by spraying or immersing the particles in the liquid.

In yet another embodiment of the invention the dispersant is an acidic or weakly basic detergent former. Examples of such substances that are compatible with the organic peracid are citric acid, mellitic acid

409848/1041

acid, pyrrotnellitic acid, maleic acid, diglycolic acid, oxydisuccinic acid, Nitrilotriacetic acid, ethylenediaminetetraacetic acid, polyacrylic acid, cyclopentane-ljZjS ^ -tetracarboxylic acid and tetrahydrofuran-2,3,4,5-tetracarboxylic acid. In combination with persaur bleach, these compounds fulfill a double task, as on the one hand they increase the rate of dissolution of the peracid and on the other hand ions that are in the Wash solution causing the hardness to intercept.

Examples of other organic acids that act as dispersants Can be used are oxalic acid, malic acid, 1,3-cyclobutenedicarboxylic acid, glutaric acid, maleic acid and malonic acid.

The core particles can be prepared by adding the dispersant in an aqueous slurry of the peracid dissolves or mixes it with such a slurry «After the addition of the dispersant, the mixture will normally well worked out to achieve an even distribution of the dispersant and peracid. To upon mixing, the slurry is converted into core particles. One method of making cores is that the slurry is made into the form of a thin layer and poured out. The frozen layer then turns into particles shredded to the desired size. An alternative method is to produce hydrous solid peracid particles by dividing the slurry of the peracid into fine particles. This can be achieved by the slurry through a spray nozzle or through a disintegrator

409848/1041

2423486

Sprinkler device leads to create liquid droplets. The liquid droplets can be mixed with an inert liquid Coolants, such as liquid nitrogen, can be brought into contact with them in order to solidify them. Other methods of Examples of production of the core particles are extrusion through a nozzle and tableting. In dependence of the thickness of the slurry does not require the particles to freeze out. Frozen particles can, however easily handled as disclosed in U.S. Patent 3,622,366. The peracid particles then become fine particles brought into contact with a material which contains the constituents of the mass for the enveloping protective coating. The encapsulation material is usually a hydratable salt or a non-hydratable salt in combination with one Binder. During encapsulation with the hydratable Salt is the salt in an incompletely hydrated state, preferably in an essentially non-hydrated form, so that it is able to * take up water as water of hydration from the core particles. For example, magnesium sulfate can per se or magnesium monohydrate serve as the encapsulating salt, the coating then being made of a hydrated magnesium sulfate which contains 1 to 7 moles of water per mole of magnesium sulfate.

The core particles can be contacted with the encapsulation material in a static bed, but will preferentially the contact brought about in a dynamic system. Ideally, the hydrous peracid particles brought into contact with finely divided salt particles in a fluidized bed. Suitable fluidizing agents for the production of the

409848/1041

Fluidized beds are inert gases under these conditions, like nitrogen or air. The procedure is such that a bed of a hydratable salt or a non-hydratable Suspended salt in combination with a binder in an ascending stream of an inert gas The core particles are then introduced into the upper part of the bed. Water that is in the hydrous Particulate matter will appear in the coating as a hydrating agent when a hydratable salt is used as a Encapsulating agent is used, and as a gelling agent, when a non-hydratable salt in combination with a binder is used as the encapsulation material. When the core particles are frozen, the temperature of the fluidizing gas is above OC.

Hydratable organic compounds are used in a similar way to hydratable inorganic salts, and non-hydratable organic compounds are on the core like non-hydratable inorganic compounds Salts applied

The dispersant and the salt used for coating can be the same compound as for the dispersant only the condition applies that it is compatible with the peracid and is more easily soluble in water than the peracid. It can be encapsulated as a result Particles of the peracid that are either too large or too small for the intended purpose in an economical manner can be reused for the production of the cores. this

409848/1041

is achieved by getting too large and too small particles bodice slurries and from this slurry in already as indicated produces core particles. Those core particles already containing the dispersant, i. the material that previously formed the encapsulation material can be re-encapsulated with a protective coating will"

In another embodiment of the invention the dispersant is a double salt. Such double salts can be obtained by adding two salts to the slurry of the peracid in proportions advantageous for the formation of the double salt. This embodiment is advantageous when the double salt has desired properties which neither of the two salts has. For example, Na ₂ Hg (SOi) ₂ * 4 H ₂ O is a double salt that is obtained in the core by slurrying peracid _{particles with Na 2} SO and MgSO in a ratio of 10: 1, a particularly advantageous dispersant. The double salt contains water of hydration, which acts as a heat consumer. _{The double salt is preferred over Na 2} SO because it forms smaller crystals that can be distributed more evenly in the peracid particles.

The encapsulated cores usually have a diameter from 0.1 to 5 mm, preferably 0.2 to 2 mm. The protective cover or encapsulation usually has an average thickness of at least 0.05 mm and preferably 0.1 to 1.0 mm. The core preferably has a diameter of 0.05 to about 5 mm. That Dispersant that is embedded in the matrix of the peracid usually has a particle size of 0.001 to 1 mm,

409848/1041

preferably 0 _f 005 to 0.5 ram.

In the invention, encapsulated cores with a complete and continuous encapsulation shell is preferred, but products that are less are also useful perfectly but essentially completely encapsulated. Even such products can be made with alkaline synthetic Mix detergents without undesired decomposition of the peracid. Generally the dispersant is an ionic material ^ Because of the incompatibility of peracids with alkaline materials, acids and acidic, neutral or weakly basic salts are preferred. These ionic compounds, their 1% aqueous solutions have a pH below 9.0, preferably from 2 to 8, are advantageous dispersants for the purposes of the invention.

The invention will be further elucidated in the following examples explained.

example 1

There are slurries of diperisophthalic acid that contains less than 5% isophthalic acid, prepared by adding the salt to be used as a dispersant in a sufficient amount of deionized water dissolves so that the The desired concentration of the salt is present when the solution is slurried with the moist cake of diperisophthalic acid will. The slurries obtained are in a

409848/1041

electrical mixing device homogenized, too thin Layers formed between polyethylene sheets and quickly frozen out with dry ice. The frozen layers will be broken up, crushed and sieved out as frozen kernels with particle sizes of -18 +70 meshes.

An encapsulation material is made by mixing Na ₂ SO, and MgSO, .1 H ₂ O in ratios of 1: 1 to 9: 1. The frozen core particles are encapsulated by contacting them with the salt particles in a heated fluidized bed 7.5 cm in diameter. Hot air, the temperature of which is selected so that a temperature of 40 to 45 ° C. is maintained, is used as the fluidizing agent. After a residence time of about 15 minutes, the contents of the fluidized bed are sieved on a ro-tap sieve shaker with sieves with a diameter of 20 cm for 2 minutes with a load of about 250 g. A product is obtained with particle sizes in the range from -14 to +60 mesh. The rate of dissolution at 50 G and 20 C of these samples and of encapsulated diperisophthalic acid without dispersant is investigated.

The dissolution rates are determined as follows:

It is produced a simulated wash solution by adding 0.15 wt.% Of a common household dissolves detergent in tap water. For each test, a 250 ml portion is placed in a 400 ml beaker, the beaker being on a hot plate with a set temperature or in a cooling bath

409848/1041

with the set temperature. A magnetic bar is used to stir at a constant speed. Sufficient encapsulated diperisophthalic acid is added to make a solution containing 60 ppm active oxygen, with stirring for a given period of time. At the end of the stirring period, all of the solution is quickly filtered through a Buchner funnel into a flask _{containing approximately 250 ml of 4.3% H 2} SO. The wet filter paper and any remaining residue are placed in another flask containing equal amounts of isopropanol and 4.3% H ₉ SO to dissolve any solids. The diperisophthalic acid is then determined in both solutions by titration with a Na ₉ S ₉ O solution. The procedure is repeated for each of several periods at 50 ° C and 2O ⁰ C. Table I summarizes the dissolution rates of encapsulated diperisophthalic acid with and without the presence of additives in the cores.

409848/1041

Table II

Comparison of the dissolution rates of encapsulated diperisohthalic acid

with and without additives in the core,

Composition in% based on encapsulated product. Dissolution rate in 0.15%

,., Detergent solutionl

covered '

Dis- at the core X '& "oil %. by- % Dis- DPI ^Δ \ IPS " greed- by- middle· greed- middle 26th .9
* 1.5 none 0 11 » .1" 0.8 O no! 0 CD OO 17th .5 1.0 -P-
OO Na ₂ SO ₄ ·. H.9 O Na ₂ SO ₄ + 2.0 9 .8th 0.5 MgSO ₄ -OH ₂ O 1.9

in coating ^

MgSO, Na ₀ SO. H ₀ O ^Lö _Sung-I% ^ given DPI dissolved after stirring 4 2 4 Z terape- ι

terape ι

temperature ⁰ C, 15 sec. 30 sec. 60 sec. 120 sec,

6o.6

25.1

22.8

NaH ₂ POa'H ₂ O NaHSO ^ -H ₂ O KHSO ₄ K ₂ SO ₄

3.0 8.5 0.5 2U.U

3.2 9-3 0.5

2.8 9.1 0.5 2l ».l

26.3

37.7 13.8 53.2 9.7

Na ₃ C ₆ H ₅ O ₇ ^ H ₂ O 3.2 9.0 0.5 2U.7. 1 * 9 · 2 13- ^y

52.8 10.8

2.8 9.I O.5 2 * 1.5 50.7 12.1 »

50. 88
98 13th
37 13th
57 OJ 20!
85 ' 20th
50 95
• 97 hey 17th
66 CD 29
90 20th
50 lh
99 91 »
99 56
99 98
100 20th
50 80
99 96
99 "98 QÖ 20th
50 87
99 81
100 97
100 98
IOC 20th
50 87
99 95
100 98
100 9B
100 20th
50 97
99 92
99 96
100 100
93 20th
50 99 97
100 98
ICO 20th
50 98
99 99
100 99
100

Continuation from Table I.

Composition in % on the encapsulated product. Dissolution rate in /, 15%

Detergent solution

in the core "

| peri

in the cover

! yaw% dispersants%%%% 1% Central greed medium DPI IPS MgSO ₇ NaSO. ¹ H ₀ O

I * l I H- IZ solution

% added DPI dissolved after stirring

° _c 15 sec. 30 sec. 60 sec. 120 sec.

Na ₂ SO ₄ + MgSO ₄ • 6H ₂

ο Na ₂ SO ₄ +

«° MgS0 ₄ -6H ₂ 0 oo

Na ₂ SO ₄ + MgSO ₄ -6H ₂ O

Na ₂ SO ₁ ,

1.5

2.8

1.0 0.9

0.7 1.3

7.9

MgS0 ₄ -6H ₂ 0 9.3

9.7

9-5

9.0

12.8 0.7 25-3

17.Ο 0.9 h8.6

^ 9.8 11.4 20th
50 94
99 97
99 98 ·
99 99
99 51.7 12.1 vji ro
0 0 95
98 - 98
99 99
99 99
100 53.0 11.2 20th
50 94
98 98
'99 98
100 98
100 41.5 12.0 O O
CU IA 99 97
99 "98
99 99
100 0 24.2 20th
50 84
. 96.. 83
99 84
100 9C
.. ICO

It is believed that all of the dispersant has remained in the core and that after ^ the Encapsulation no free water (only water of hydration) is present in the core.

DPI ** Diperisophthalic acid ³ IPS = isophthalic acid to

J-O

CD

Example 2

Two encapsulated diperisophthalic acid formulations for testing purposes are prepared in a manner similar to Example 1. Sample A consists of capsules with cores of diperisophthalic acid, which make up 26.9 % by weight of the capsules. The kernels also contain isophthalic acid, which makes up 1.8% of the capsules. These cores are coated with a coating mass of MgSO and H ₂ O, this mass corresponding to 45.2 or 26.1% by weight of the capsules. Sample B is produced in a similar manner, but the cores contain MgSO, .6H ₂ O, diperisophthalic acid and isophthalic acid in proportions of 9.5% by weight, 17.3% by weight and 0.8% by weight , based on the weight of the capsules. The cores of the capsules B are provided with a coating mass of MgSO ,, Na ₂ SO, and H ₃ O in proportions of 20.7 wt.%, 39, 1 wt., And 12.6 wt.% ₉ based on the weight of the capsules , encapsulated.

Ordinary city tap water containing 0.15% of a commercially available detergent is used to determine the dissolution rates. A 250 ml portion of the test solution into a 400 ml beaker is placed for each test and the temperature is adjusted to 20 or 5O ⁰ C. It is stirred with a magnetic stir bar.

Sufficient encapsulated diperisophthalic acid is placed in the beaker to make a 60 ppm solution to give active oxygen, and the contents of the beaker are stirred for the allotted time. The one in one

409848/1041

The amount of diperisophthalic acid dissolved in a given period of time is determined as in Example 1.

The relative rates of dissolution of the diperisophthalic acid alone and the diperisophthalic acid with the dispersant are plotted graphically in the drawing. From the drawing that the diperisophthalic acid, containing a dispersant, both at 20 and dissolve much faster even at 50 ⁰ C as the diperisophthalic acid without addition of a dispersant is apparent.

409848/1041

Claims (16)

Patent claims 1. Formulation of an organic peracid in the form of a encapsulated core, characterized in that the. Core particle of a solid organic peracid in admixture with particles of a dispersant which is essentially in water is more soluble than the organic peracid, the core being essentially dispersible in a water Material is encapsulated that in the absence of water is capable of contact of the peracid with Avoid substances that can cause them to decompose. In that the core or the Einkapslungsmaterial contains a hydrated salt 2. Formulation according to claim 1, characterized in that keeps the water of hydration below 30 ⁰ C, but at least add a part of water of hydration below 150 C, wherein the hydrated salt present in an amount is to provide at least 0.1 part by weight of water of hydration per part by weight of organic peracid. 3. Formulation according to claim 2, characterized It is understood that the hydrated salt is present in an amount sufficient to at least To provide 0.25 parts by weight of water of hydration per part by weight of peracid. A 0 9 8 k 8/1 G 4 1 4. Formulation according to one of claims 1 to 3, characterized characterized in that the peracid is a perphthalic acid. 5. Formulation according to claim 4, characterized in that that the perphthalic acid is diperisophthalic acid. 6. Formulation according to one of claims 1 to 5, characterized ^ that the core contains 1 to about 90% by weight of a dispersant which is soluble in water
1 g to 100 g of water. that in water has a solubility at 15 C of at least 7. A formulation according to any one of claims 1 to 5, characterized in that the core contains from 2 to 75 wt.% Of a dispersant in water at 15 C a '.
100 g of water. Water at 15 C a solubility of 2 to 200 g per 8. Formulation according to one of claims 1 to 5, characterized in that the core contains 5 to 60 wt .
100 g of water. Water at 15 C has a solubility of 4 to 200 grams per 9 «formulation according to any one of claims 1 to 8, characterized characterized in that the dispersant and the encapsulating material are both a substance 409848/1041 from the group of sodium acetate, monobasic sodium phosphate, dibasic sodium phosphate, sodium sulfate, sodium potassium tartrate, acidic sodium tartrate, magnesium acetate, magnesium ammonium sulfate, aluminum nitrate, aluminum sulfate, aluminum magnesium nitrate and potassium benzoate in either the hydrated or non-hydrated form. " 10. Formulation according to one of claims 1 to 8, characterized characterized in that the dispersant is potassium magnesium sulfate, potassium sulfate, acidic Potassium sulfate, sodium oleate or sodium phthalate. 11. Formulation according to one of claims 1 to 8, characterized characterized in that the dispersant is an acidic or weakly basic detergent former is. 12. Formulation according to one of claims 1 to 8, characterized in that the dispersant is Na ₉ Mg (SO,) ₀ in hydrated or non-hydrated form. 13. Formulation according to one of claims 1 to 12, characterized characterized in that the peracid contains at least 30% by weight of active oxygen. 14. Formulation according to one of claims 1 to 13, characterized characterized in that the encapsulated core is substantially spherical and has one 409848/1041 Has a diameter in the range of about 0.1 to 5 mm. 15. Formulation according to one of claims 1 to 8, characterized characterized in that the dispersant or the encapsulating material or both a substance from the group of magnesium sulfate, sodium aluminum sulfate, potassium aluminum sulfate, ammonium aluminum sulfate, Are potassium nitrate and sodium nitrate. 16. Formulation according to one of claims 1 to 8, characterized characterized in that the dispersant is a material which has a solubility of more than one percent by weight in water at 15 ° C possesses, is compatible with the per acid and its 1% aqueous solution has a pH in the range of 2 to 8 has. 409848/1041