KR960008939B1 - Peroxygen laundary bleach - Google Patents

Abstract

None.

Description

Peroxide Laundry Bleach

The present invention relates to solid compositions which are stable when releasing hydrogen peroxide in the presence of water and incorporating it into solid household and laundry detergents.

It is well known that peroxide compounds can be used as bleaching compounds in detergent powder mixtures. In ordinary household detergents, sodium perborate tetrahydrate is generally used as bleaching compound because it is harmful to plants but relatively stable to decomposition in powdered detergent media. However, sodium perborate tetrahydrate has the disadvantage of dissolving too slowly, especially in cold water. Sodium perborate monohydrate, on the other hand, dissolves rapidly, but the particles are brittle and generally decompose into powder. Both of these forms are undesirable for the environment because one mole of boron compound is added to the environment per mole of active oxygen.

In order to rectify this drawback, it has been proposed that powder detergents can be used in admixture with other peroxygen compounds with a suitable dissolution rate, in particular alkali metal percarbonates, superphosphates and peroxymonosulfates. These peroxygen compounds, especially percarbonates, decompose very quickly into powder form, especially when stored in wet atmosphere. In addition, other components in the moisture and cleaning compounds promote this degradation.

Particles of the peroxygen compound can be selected from a variety of compounds such as trona (US Pat. No. 4,105,827); Sodium silicate (US Pat. No. 3,951,838); Sodium perborate + sodium silicate (US Pat. No. 4,194,025); Boric acid (US Pat. No. 4,321,301); Waxes (US Pat. No. 4,421,669); Polymer latex (US Pat. No. 4,759,956); Sodium silicate + chelate (US Pat. No. 4,117,087); And coating with wax + fatty acid (US Pat. No. 4,126,717) has been proposed in the prior art. Many of these treatments exhibit short-term storage stability in wet environments.

Generally, this process involves: 1) physically coating sodium carbonate peroxide with a compound such as trona, boric acid, or the like, such that the peroxygen compound (eg, sodium carbonate perhydrate) is in physical contact with other compounds in the detergent composition. Or as a spacer, or 2) coating the peroxygen compound with a vapor barrier such as wax or polymer. The two processes were unsuccessful because a simple physical coating would allow water vapor to seep into the particles and cause decomposition, and coating with a layer that did not see water would delay the dissolution rate of the particles and render them useless.

The present invention overcomes the difficulties of the prior art by providing a process for preparing a compound that is stable for storage, comprising the following steps:

(a) particles of substantially dry particles comprising 0.1 to 3% by weight of diphosphonic acid or diphosphonic acid salt and sodium carbonate peroxide containing 1 to 5 moles of anhydrous sodium carbonate for each mole of available water contained therein. Suspending sufficiently to almost eliminate solid-solid contact between

(b) contacting the dried particles with a plurality of aqueous solutions aesthetics consisting essentially of a mixture of 1 to 99 parts by weight sodium silicate and 99 to 1 part by weight sodium metaborate,

(c) simultaneously evaporating nearly all of the water at a rate sufficient to avoid wetting or hydration of the dry particles, thereby coating the dry particles by 2 to 10 weight percent

(d) collecting dry particles coated as stable free-flowing peroxygen compounds when incorporated into the solid detergent formulation.

The coated particles may be recycled in step (a), thereby providing two or more coatings.

The scope of the present invention is intended to include the product produced by the above process.

Any composition can be used containing 1-5 molar excess of sodium carbonate (anhydrous) and dry particles including sodium carbonate perhydrate with 0.1% to 3% diphosphonic acid.

One skilled in the art can readily prepare preferred nonpolymerizable sodium carbonate perhydrate compositions, Soda Ash Peroxygen Carrier, (SAPC) according to the process described in US Pat. No. 4,966,762. This process adds a solution of diphosphonic acid or diphosphonic acid, preferably 1-hydroxy ethylidene-1,1-diphosphonic acid, in modified hydrogen peroxide to the particles of anhydrous sodium carbonate and simultaneously removes water vapor from the surface of the reaction mixture. And maintaining the temperature of the reaction mixture at about 35 ° C. to 80 ° C., wherein the diphosphonic acid or diphosphonic acid salt is present in the composition in an amount to provide 0.1% to 3% of the diphosphonic acid or diphosphonic acid salt. Provided as product is a soda ash peroxygen carrier containing 1 to 5 moles of sodium carbonate for each mole of available water in the composition, consisting essentially of water, crystalline water and free water chemically available as hydrogen peroxide.

Diphosphonic acid slows the rate of hydration of anhydrous sodium carbide so that water preferentially evaporates. However, after the product is dried, anhydrous sodium carbonate can form a hydrate with any water formed by the decomposition of peroxygen. Pure soda ash peroxygen carriers thus suffer less accelerated degradation than sodium carbonate perhydrate.

Clearly, a problem with the prior art coating process is that the sodium carbonate perhydrate decomposition process produces 1.5 moles of water for each mole of sodium carbonate perhydrate, and if the vapor does not seep, the coating prevents the evaporation of water. As a result, the retained water promotes the decomposition of sodium carbonate perhydrate. On the other hand, if there is no water vapor in the coating, the moisture in the detergent formulation may be in contact with sodium carbonate perhydrate and may initiate decomposition.

The present invention can be carried out in a fluid phase by suspending dry particles with a flowing gas and applying the coating by spraying.

To eliminate solid-solid contact for the purposes of the present invention. Suspension includes raising particles separately by a stream of air or lowering them separately as in a tower. Alternatively, the present invention can be carried out in a tower and the coating can be applied by countercurrent, countercurrent or radial spraying. Spray drying with other optional processes, such as injection of both liquids and solids, will be apparent to those skilled in the art.

Drops of the aqueous solution, the surface of the dried particles of wet particles of sodium carbonate in the or dry particles to avoid agglomeration fruit cargo (SPC), or is any of sodium carbonate hydrate of the SPC _{hydrate, 2Na 2 CO 3 · 3H 2} O · 2H It is important in the present invention to have a diameter smaller than the solid particles to avoid the formation of ₂ O ₂ , sodium carbonate hydrate or other hydrates. Once the hydrates are formed, it is very difficult to dehydrate the monohydrate without simultaneously decomposing the active oxygen combined with sodium carbonate monohydrate.

The best mode for carrying out the invention will be apparent to those skilled in the art from the following non-limiting examples. Unless stated otherwise,% is% by weight.

[Stability Test]

Quick Test is a method of measuring the relative stability (degradation) of similar samples for only 8 hours. Sufficient samples are added to a closed container connected to the pressure gauge to provide a constant volume to sample weight ratio. The temperature is kept at 50 ° C. and oxygen is released (the increase in pressure is measured every hour and the slope of the line is recorded as cm / Hg). The test can be used for samples formulated on a detergent substrate or for samples of unmixed peroxygen compounds (pure stability).

The 80/80 Open Box Test simulates the storage of open boxes of detergent formulations. Unless stated otherwise, a specific sufficient amount of peroxygen compound to be evaluated is blended with a commercial detergent formulation to provide 0.7% by weight of active oxygen. The box containing 0.45 kg of formulation is opened for 6 weeks with the lid open at 26.7 ° C. (80 ° F.) and 80% relative humidity. Samples are selected at two week intervals by ripple the contents of the box. Activated oxygen is measured three times.

[Coating Process]

The apparatus used to coat the dry particles is a Strea-1 Laboratory Fluid-Bed Coater manufactured by Niro Industries, Inc., Aeromatic.

The unit consists of a coating material supply container, a tubing pump for dispensing the coating liquid and a fluid phase coater. The fluid phase coater consists of a central absorbent tube containing a transparent outermost layer for easy viewing, a grating for introducing flowing air, and an air spray nozzle. The product introduced into the vessel flows from below the grating by a stream of preheated air. The particles to be coated are recycled through the draft tube until the desired amount of coating material is applied.

[Coating Procedure]

1. Set a specific setting between the grating and the bottom of the center tube.

2. Adjust the nozzle spray cap to set the nozzle rage air to the desired setting.

3. Preheat the fluid phase apparatus to the coating temperature.

4. Fill the phase coater with the required amount of peroxygen compound.

5. Heat the contents using the preheated air used to flow the contents at a gentle flow rate.

6. After obtaining a bed temperature of 38 ° to 71 ° C. (100 ° to 160 ° F.), preferably 48 ° to 60 ° C. (120 ° to 140 ° F.), increase the air anger rate and fluidized bed rate, preferably Starts coating application at a predetermined rate.

7. When applying the coating, adjust the inlet air speed and temperature to maintain the phase temperature. It also maintains the coating material application rate.

8. After applying the required amount of coating, the coating pump is driven into the supply vessel to empty the line of coating material, the air preheater is deactivated, the fluid air stops entering the fluid phase, and the contents of the vessel are emptied.

9. Weigh the coated material.

The coating procedure uses a variety of materials: sodium silicate, sodium metaborate, sodium borosilicate, sodium bicarbonate, sodium carbonate, sodium polyacrylate, polyethylene glycol and polypropylene glycol.

It is essential to avoid substantially agglomeration of the particles. Agglomeration is easily measured by reduction in bulk density. For example, an uncoated SAPC with a bulk density of 1,025 kg / m 3 (64 lb / cu.ft.) May be at least 800 kg / m 3 (50 lb / cu.ft.) After coating, preferably at least 880 kg / m 3 (55 lb) /cu.ft).

The particles are coated with 2-10% by weight of the coating compound. Only one coating material may be applied, or may be applied as a mixture or in combination as multiple coatings. The coating effect is determined by the method (hydrogen peroxide content) in which the coated particles maintain free radicals in the quick test and the open box test.

The solution of the coating compound can vary widely in concentration. The solution preferably contains about 15% to 25% solids. Concentrations of more than 25% may be used, but they should usually be preheated to prevent crystallization and to arouse aesthetics. Thinner solutions require greater heat input to evaporate the water sufficiently to prevent the particles to be coated to wet. The cautious solids range of the solution is from about 12% to about 35%.

A typical 25% solids solution preparation is illustrated below:

Sodium metaborate: 261.8 g sodium metaborate tetrahydrate is added to 238.2 g water.

Sodium silicate: 334.4 g of 37.4% sodium silicate solution (SiO ₂ : Na ₂ O weight ratio = 3.22) is added to 165.8 g of water.

Sodium borosilicate: blend of the solution (1: 99 to 99: 1 ratio)

The best way to carry out the invention is illustrated using the preferred SAPC, since insufficient evaporation of water in step (c) will be easily detected by conversion of anhydrous sodium carbonate to hydrate.

A soda ash peroxygen carrier (SAPC) initially containing about 9.0% active oxygen is prepared using two commercial grade sodium carbonates, soda ash of grade 100 and soda ash of FMC Corporation. Samples are coated and stability is measured by quick test in cm / hr. The details and results of the experiments are reported in Table 1. Grade 90 soda ash is more absorbent than grade 100 soda ash.

From the table it is clear that the type of sodium carbonate does not affect the stability of the resulting SAPC before or after coating. In general, SAPC coatings reduce the rate of degradation.

Example 2

Coated and uncoated SAPCs are evaluated only by quick test (pure stability) and combined with commercial detergents (non-phosphate Tide of PG). Sufficient SAPC is used to provide 0.7% free oxygen (AO) in the formulation. The results are shown in Table 2.

It is important to note the difference in% of free radicals (AO) when comparing the rate of decomposition. All detergent formulation samples initially contain 0.7% AO and samples with pure stability contain 10-13 times (7.0-9.4% AO).

The table shows that the particles coated according to the invention are more stable (less decompose) in detergent formulations than uncoated particles, and can be compared with tide's sodium perborate perborate monohydrate with bleach.

Example 3

Samples of SAPC coated with sodium silicate, sodium metaborate and sodium borosilicate are evaluated in an open box test. The results are shown in Table 3. Commercial tide with bleach containing 0.7% AO as sodium perborate monohydrate is used as a control.

It is clear from Table 3 that the coated samples are generally more stable than commercial formulations containing stable sodium perborate monohydrate.

Example 4

Under the same temperature and stirring conditions, SAPC coated with 2% borosilicate dissolves 95% after 1 minute at 15 ° C., and only 30% of the sample of sodium perborate tetrahydrate dissolves. SAPC coated with 10% borosilicate also dissolves 88% at the same time.

Example 5

A sample of soda ash peroxygen carrier prepared by the process of US Pat. No. 4,966,762, and commercially available sodium carbonate perhydrate containing silicate and magnesium stabilizer, 2% and 10% borosilicate (about 50% by weight sodium metaborate and 50%) % Sodium silicate). Samples are incorporated into non-phosphate tide detergent to provide 0.7% free radicals (A.O.). After six weeks of storage, stability is measured in an open box test. The results are reported in Table 4 and compare samples of commercially available tide with bleach and a tide detergent consisting of sodium perborate monohydrate.

The data show that the coating somewhat improves the stability of commercial sodium carbonate perhydrate samples and that the stability of SAPC with 2% coating unexpectedly increases about 5 times.

Example 6

The dissolution rate of the coated peroxygen compound is compared by measuring the change in active oxygen (A.O.) over time. Sufficient peroxy compound was added to the final A.O. Providing content; The sample is stirred at 200 rpm.

Sodium perborate monohydrate (uncoated), known to dissolve very quickly, dissolves almost all within 10 seconds, and only 50% of the uncoated sodium perborate tetrahydrate dissolves up to 120 seconds.

Samples of SAPC coated with 2% and 4% sodium borate are both almost dissolved (90%) within 40 seconds, and samples of SAPC coated with 6%, 8% and 10% are almost all dissolved within 60 seconds (90 %). A sample of SAPC coated with 2% sodium silicate relative to the initial 2% sodium metaborate dissolves only 80% after 120 seconds.

Coatings of 2% or more sodium metaborate are too viscous and difficult to handle, which only aggregates. In fact, when sodium metaborate is applied on sodium carbonate perhydrate (sodium percarbonate), sodium metaborate must be used in excess sodium silicate. It is the reverse of that described in Japanese Patent No. 59-193999, which is described. Clearly, SAPC coated with mixed sodium borate / sodium silicate (sodium metaborate) is superior to commercially available sodium percarbonate (2Na ₂ CO 3 .3H ₂ O ₂ ) coated.

2nd floor

Degradation comparing SAPC alone detergents and formulated detergents

All test samples contain 0.7% A.O. in non-phosphate tide.

Claims (4)

(a) between the particles substantially dry particles comprising 0.1 to 3% by weight of diphosphonic acid or diphosphonic acid salt and sodium carbonate peroxide containing 1 to 5 moles of anhydrous sodium carbonate for each mole of available water contained therein Suspending sufficiently to almost eliminate the solid-solid contact of (b) the dried particles comprising a plurality of essentially consisting of 10 to 90% by weight sodium silicate and 90 to 10% by weight sodium metaborate (sodium borosilicate) Contacting an aqueous solution aesthetic, (c) simultaneously maintaining the dry particles at a temperature of 38 ° C. to 71 ° C. to evaporate water at a rate sufficient to avoid wetting or hydration of the dry particles, and Coating with 2 to 10% by weight sodium borosilicate, and (d) drying coated as a stable free-flowing peroxygen compound when incorporated into the solid detergent formulation. A method for preparing a storage stable compound, characterized in that the particles are collected. The process of claim 1 wherein the aqueous solution consists essentially of 15 to 35% solids consisting of 25 to 75% by weight sodium silicate and 75 to 25% by weight sodium metaborate. The product produced by the process of claim 1. A product made by the process of claim 1 further characterized by having a bulk density of at least 800 kg / m 3.