CN101679917B - Process for the preparation of coated sodium percarbonate - Google Patents

Abstract

A process for the preparation of coated sodium percarbonate containing particles, comprises (a) a manufacturing step of sodium percarbonate containing core particles, comprising the crystallisation of sodium percarbonate from aqueous solution and the separation from aqueous so lution, (b) an at least partial drying step of the sodium percarbonate containing core particles, (c) a coating step comprising the application of a base coating on the so obtained core particles with one or more sodium percarbonate containing or generating solutions and/or suspensions, and optionally one or more additives, (d) a coating step comprising the application of a further coating on the particles from the previous step with sodium sulphate and sodium carbonate and optionally one or more additives and (e) a drying step of the coated sodium percarbonate containing particles, wherein step (c) and optionally (d) are carried out in a fluid bed reactor and the base coating of step (c) represents more than 20 % by weight of the sodium percarbonate containing core particles.

Description

Method for the preparation of coated SPC-D

The application requires the rights and interests of the European application submitted on May 2nd, 2007 number 07107379.5, is combined in by reference this.

Foreword

The present invention relates to a kind of for the preparation of showing the coated method containing sodium percarbonate granules (PCS) of improved storage characteristics, particle and their purposes in detergent composition so obtaining.

SPC-D (or peroxide hydrated sodium carbonate, 2NaCO ₃.3H ₂o ₂) purposes as SYNTHETIC OPTICAL WHITNER in the detergent composition that the washing of family yarn fabric or bowl dishwashing are washed is well-known.Conventionally, this type of detergent composition also contains zeolites as builder material, enzyme, bleach-activating agent class and/or perfumery except other components.

Known production SPC-D has multiple diverse ways, and among them, so-called crystallization method comprises crystallization and the separation from this aqueous solution of SPC-D from the aqueous solution, for example, use salting-out agent, as sodium-chlor etc.Additive method has utilized fluidized-bed reactor, and the solution that its medium and small seed grain sprays sodium carbonate and hydrogen peroxide by the stoichiometric ratio with suitable is grown.

Although crystallization process needs energy still less, but they have following shortcoming in general,, the particle producing often contains salting-out agent, and because erose particle has a large surface to volume ratio, these particles more may be easy to occur wearing and tearing and percarbonate premature decomposition.

On the other hand, fluidized bed process is produced the particle with smooth surface and good polishing machine, yet, to introducing the needs of reactant in solution and energy violent evaporation is subsequently disadvantageous economically.

Therefore, for reduce costs technically and still obtain the PCS particle with superperformance in all benefit and in the effort done, two kinds of methods have been carried out to combination, for example, by the coated seed grain obtaining by crystallization from solution in fluidized-bed reactor.

In order to use in detergent composition or mixture, percarbonate should preferably present the standing storage characteristic of optimization.

First aspect among these standing storage characteristics is the stability in storage of percarbonate.Therefore in fact, the interaction between SPC-D and other system component has caused the decomposition gradually of percarbonate, and causes the forfeiture gradually of whitening capacity in the storage of composition and transportation.This standard is also called the stability in washing composition, and can be expressed as available oxygen (AvOx) yield rate.

In addition the different Segregation that, second relevant consideration of the standing storage characteristic of mixture is related to their each components.In other words, for fear of or at least reduce due to store and detergent composition that transportation brings in progressive unhomogeneity, percarbonate particles also should show enough resistance to segregabilities.Therefore, although segregation is the very complicated thing that comprises a plurality of parameters, statement " resistance to segregability (segregation resistance) " is interpreted as percarbonate and compares with other compositions in composition with the ability that significantly similar mode shows under this background, and the progressive unhomogeneity of composition is lowered or postpones thus.

Significantly, this two specific character is not suitably considered in previous trial simultaneously, causes thus how many poor trading off.

Goal of the invention

Therefore, the object of this invention is to provide a kind of method for the manufacture of novel sodium percarbonate granules, when described particle is before use in the product in a kind of preparation during through the storage of a rapid lapse of time and transportation, compare with known sodium percarbonate granules, present improved standing storage characteristic, in conjunction with the resistance to segregability of a kind of better extended storage stability and a kind of enhancing.

Invention general description

In order to address the above problem, the present invention proposes for the preparation of method coated, that contain the particle of SPC-D, comprising:

(a) manufacturing step of the core particle that contains SPC-D, comprises separated with from the aqueous solution of the crystallization of SPC-D from the aqueous solution,

(b) and an at least part of drying step of the core particle that contains SPC-D,

(c) coated/granulating step, this step comprises uses one or more solution and/or the suspension that contains or produce SPC-D, and optionally with one or more additives, on the core particle so obtaining, applies a substrate coating layer,

(d) encapsulation steps, this step comprise with sodium sulfate and sodium carbonate and optionally one or more additives on the particle from previous step, apply another coating layer, and

(e) drying step being coated, contain the particle of SPC-D, wherein, step (c) and optionally (d) and/or (e) be to carry out in a fluidized-bed reactor, and the representative of the substrate coating layer of step (c) by this, the weighing scale containing the core particle of SPC-D is greater than 20%.

As it was suggested in foreword, optimum covering amount will be that storage stability and resistance to segregability are all taken into account is constructive compromise, this storage stability increases with the minimizing of area and the ratio of the volume growth of granularity (along with) to a certain extent, and this resistance to segregability is a complicated parameter, it depends on the granularity of the percarbonate that (except other things) compared with size-grade distribution with the granularity of other compositions and size-grade distribution, together with the relative bulk density of particle.Percarbonate particles should, for example, there is granularity, size-grade distribution and bulk density that other compositions with detergent composition roughly match.

Therefore core particle by crystallization gained has irregular shape, and has the ratio of relatively large area and volume.

Do not wish to be subject to any theoretical institute to fetter, observe, in the coated process of this class percarbonate particles, a first stage, although their size only increases lentamente due to the hole of erose particle and the preferred filling in chamber, their bulk density is stable rising.In other words, the distribution of sizes of particle remains substantially invariable in this stage, and has therefore retained greatly the distribution of sizes of initial cores particle.

An other stage, when erose core particle capped take how much form as level and smooth when surperficial, particle continued growth, but their bulk density reached zero growth.On the other hand, if continue to be coated, size-grade distribution (as what weighed by " span " of size distribution curve) will start to decline, thereby cause having the particle of more and more same sizes, and as already mentioned, this is harmful to resistance to segregability.

In operation, the first stage of growth bulk density finishes when the coated value that is greater than by weight 20%, and subordinate phase be generally for core particle (mean particle size that depends on them) by weight higher than its undesired effect of 30% to 50% value place demonstration.

Fig. 1 illustrates size-grade distribution (psd) and utilizes the particle growth of higher fluid bed granulation coating layer and the effect that span reduces: has been shown in dotted line and there is the mean particle size of 385 μ m and the initial product of 0.87 span, and the distribution of solid line representative after 45% fluid bed granulation coating layer by weight.Granularity is increased to 438 μ m and span is reduced to 0.59.Thinner pellet fades away.

Therefore,, after filling these holes, granularity increases and span reduces.

Because establishing, " top condition " of present method can be easily gets by measuring the differentiation (according to ISO 3424) of bulk density of the coatedparticles of gained, for example by making a sample be placed in the funnel of 50mm directly over this cylinder from one in the stainless steel cylinder an internal height and diameter are 86.1mm, (top internal diameter is 108mm, bottom internal diameter 40mm, height 130mm) after flowing out in, record the quality of this sample and measure.

Funnel is placed on a frame, and receptor is put into its working position.The bottom opening of funnel covers by closure plate (closure plate), by this plate gently be close to funnel.Sample arrives the upper edge of funnel thus, then closure plate is removed rapidly, makes like this content in funnel flow into receptor and therefrom overflow.Make carefully the content in susceptor flush with linear edge, and then rap receptor so that powder is fine and close.Finally, remove receptor, with dry cloth, outside dried and again weigh.

Therefore, the storage stability of sodium percarbonate granules in detergent composition and resistance to segregability can be to be greater than by weight 20% but be less than by weight generally 100%, be preferably less than by weight 50% and be more preferably less than by weight 35% coating layer and mutually optimize by using with respect to core particle.

In the present invention, at manufacturing step (a) and/or drying step (b), preferably in step (a), for example, by adjusting the distribution of crystallization condition (for example, by changing stirring velocity) or a kind of reactant, and/or by additional screening step (preferably in step (b) afterwards and in encapsulation steps (c) before), the suitable size-grade distribution of coated sodium percarbonate granules can be controlled by adjusting the distribution of sizes of core particle easily.

Fig. 2 shows the contrast of bulk density (BD), span and coated level and duration of test runs, and has shown the span, bulk density (BD) of size-grade distribution (psd) and the relation between coated/granulating level.Vertical black line mark be size-grade distribution region of (span reduces) in variation wherein.This effect starts from 30% the be coated/granulating level by weight for core particle.In this test, the concentration of soda ash solution is 30%.

As mentioned, the amount that total bulk density of particle passes through applied coating layer is advantageously increased.In fact, from step (a) and in step (b) bulk density of dried core particle be to be less than about 1g/cm generally ³.When applying coating layer in process in accordance with the present invention (c), bulk density is stably increased to approximately 1.10 to 1.18g/cm ³value, this is because the covering amount in step (c) has surpassed by weight 20% of core particle.Therefore, coated sodium percarbonate granules of the present invention has at least 0.9g/cm conventionally ³, 1.0g/cm at least particularly ³bulk density.It is maximum 1.2g/cm generally ³, 1.1g/cm especially at most ³.

In addition, the wearing and tearing of coated sodium percarbonate granules of the present invention (being also an aspect of storage characteristics) are very low, as measured according to iso standard method 5937-1980, normally maximum 8%, particularly maximum 5%, especially maximum 3%, and be at least 0.05% as a rule.

Different from opinion before, the dissolution time of particle (being expressed as 90% dissolution time) is not subject to the obstruction of the coated degree used in the present invention significantly, and this is described by the good experimental dissolution time from approximately 1.5 to 2 minutes.Coated sodium percarbonate granules of the present invention has at least 0.5min, particularly 90% dissolution time of 0.7min at least conventionally.In general, this 90% dissolution time is maximum 3min, especially at most 2.5min.This 90% dissolution time be at 15+/-1 ℃ and with the concentration of 2g/l, coated sodium percarbonate granules is added to the water after conductivity 90% required time of realizing its end value.The method of using is to be adjusted and obtained by the ISO 3123-1976 for industrial perborates, and unique difference is that the height of agitator is the beaker (internal diameter 120mm) of 10mm and 2 liters from beaker bottom.

Fig. 3 show the solvent time with according to the contrast of the per-cent of the dissolving of three measured percarbonate samples of method described above:

A sample that there is no fluidized-bed (FB) layer: after 128s, 90% dissolves

A sample with 26% FB layer: after 113s, 90% dissolves, and

A sample with 46% FB layer: after 137s, 90% dissolves

Therefore, between added fluidized-bed (FB) granulating coating layer and dissolution time, do not have associated.

The coating layer that comprises sodium sulfate and sodium carbonate applying in step (d) preferably coating and can by any known mode, preferably in fluidized-bed or mixing tank, utilize the solution separating of sodium sulfate and sodium carbonate or mixture to apply, wherein a part for these compounds can also be incorporated to or be applied as dry granules as the solid granule of any one or both in these compounds.In fact; in a preferred embodiment; this vitriol-carbonate coating layer can apply with two or more diverse ways in two or more stages of separating; these methods for example comprise: the applying of a first protection package coating of the mixture that contains solid sodium carbonate and sodium sulfate in a mixing tank; another coated stage subsequently; this stage is included in applying of a second protection package coating in fluidized-bed reactor, and this coating layer comprises the mixture of sodium carbonate and sodium sulfate.

Have been found that when using this coating layer comprise sodium sulfate and sodium carbonate, compare with only using one of them coating layer of these compounds, the stability of above coated particle has obtained significant enhancing.In addition, compare with the coating layer that only contains sodium sulfate, these coating layers have advantages of the sodium carbonate that combines real mass, this sodium carbonate is different from sodium sulfate, it is a kind of washing assistant useful in detergent composition, and sodium sulfate is only a kind of weighting agent and is useless for the washing composition producer.

The coating layer with sodium sulfate and sodium carbonate of step (d) preferably includes 70: 30 to 30: 70 by weight, preferably 65: 35 to 35: 65, still more preferably 60: 40 to 40: 60 and most preferably the sodium sulfate of 57: 43 to 43: 57 compare sodium carbonate.

Preferably, step (d) have sodium sulfate and sodium carbonate and optionally the coating layer of one or more other additives represent generally with respect to their core particle of substrate coating layer and be greater than by weight 1%, be preferably greater than by weight 2% and be more preferably greater than by weight 3%, but be less than generally by weight 50%, be preferably less than by weight 25%, be more preferably less than by weight 15% and be still more preferably less than 10% coating layer by weight.

Coated sodium percarbonate granules of the present invention has at least 300 μ m, particularly at least 400 μ m and the mean particle size of at least 500 μ m more particularly.The value that this mean particle size maximum is 1600 μ m, especially maximum 1400 μ m, be 1000 μ m to the maximum is preferred, for example, be 800 μ m to the maximum.

The mean particle size of particle can be used a screening plant (sieve that contains at least 6 known sieve apertures) measure to obtain several parts and every part is weighed.Then according to following formula, the mean particle size (MPS) that μ m is unit is take in calculating

$\mathrm{MPS}=0.005\underset{i=0}{\overset{n}{\mathrm{\Σ}}}\left[m_i(k_i+k_{i+1})\right]$

Wherein, n is the number (not comprising screen tray) of sieve, m _ithe weight fraction (representing with %) on sieve i, k _iit is the sieve aperture (take μ m as unit) of sieve i.Index i increases along with the increase of sieve aperture.Screen tray represents with index 0, and aperture is k ₀=0 μ m, m ₀that this screening process is retained in the weight in screen tray afterwards.K _n+1equal 1800 μ m, and be the maximum value of considering MPS calculation result.A typical screening plant that provides reliable results is defined as follows: n=6; k ₆=1400 μ m; k ₅=1000 μ m; k ₄=850 μ m; k ₃=600 μ m; k ₂=425 μ m; k ₁=150 μ m.

The span of size-grade distribution can be used the screening plant that contains 6 sieves described above measure to obtain several parts and each part is weighed.Then according to following formula effective span:

Wherein, n: the number of sieve (not comprising screen tray),

M _i: the weight fraction on sieve i, by %

K _i: the i sieve aperture of sieve, by μ m

Index i increases along with the increase of sieve aperture

Screen tray represents to have k with index 0 ₀the hole of=0 μ m, and m ₀that screening process is retained in the weight in screen tray afterwards

K _n+1: 1800 μ m, and be the maximum particle size of considering that span is calculated

MPS is the mean particle size calculating according to above explanation.

Coated sodium percarbonate granules of the present invention has improved stability in washing composition.Stability in washing composition is expressed as the AvOx (or effective oxygen) after the storage time of 8 weeks under 32 ℃ and 80% relative humidity.

Fig. 4 shows the improvement of the stability in washing composition: by the IECA of 15% PCS and 85% ^*mixed middle for some time that stores 8 weeks of carton box (laminated carton) that is incorporated in a plurality of laminations of substrate.Every 2 weeks, analyze a carton box.The reduction of resulting AvOx is shown in Figure 4.

Sample 1 (contrast), is labeled as crystallization process PCS+ 6% coating by weight, is prepared as follows:

From the PCS of crystallization process, in Glatt spray-dryer, use the coated solution of being made by the sodium carbonate of 50% sodium sulfate and 50% to be coated.

Sample 2 (according to the present invention), is labeled as the coating of the crystallization process PCS+6% of the FB PCS coating layer by weight with 24%, is prepared as follows:

On the initial PCS of sample 1, apply by weight the fluidized-bed PCS coating layer of 24% (initial WP PCS core), and coating is identical method as described in sample 1 and carrying out.

Coated sodium percarbonate granules of the present invention has good preservation or the stability in washing composition, and especially long-term stability in storage, and this can express in two different ways.

According to first kind of way, be expressed as and 1g product stored in the sealed ampoule of a 3.5ml at 40 ℃ to the thermal output of measuring after 12 weeks at 40 ℃.By microcalorimetry, the measurement of thermal output is comprised with LKB2277 biological activity monitor and utilizes hot-fluid or heat leak principle.Hot-fluid between the ampoule that contains coated sodium percarbonate granules and a temperature controlled water-bath is measured, and compared with a kind of reference material with known response heat.These permanent stability are less than 10 μ W/g generally, are particularly less than 8 μ W/g, are preferably less than 6 μ W/g, and are most preferably less than 4 μ W/g.

According to the second way, these permanent stability are to be expressed as AvOx (or effective oxygen) yield rate product of 1g being stored in the sealed ampoule of a 3.5ml at 55 ℃ after 8 week.AvOx yield rate is corresponding to the difference that stores effective oxygen before and afterwards, and this difference table is shown the per-cent of initial effective oxygen.Effective oxygen is by following illustrated measurement.AvOx yield rate is at least 60% under many circumstances, and especially at least 70%, at least 75% value is most suitable, and those values of at least 80% are preferred.

Coated sodium percarbonate granules of the present invention has by weight at least 12.0% conventionally, at least 13.0% effective oxygen by weight particularly, and at least 13.5% content is gratifying especially by weight.That the content of available oxygen is by weight is generally maximum 15.0%, particularly maximum 14.0%, for example maximum 14.2%.The content of available oxygen is by use, to be dissolved in sulfuric acid potassium permanganate afterwards to carry out (referring to the iso standard 1917-1982) that titration is measured.

In above method, solution and/or the suspension that contains or produce SPC-D is preferentially selected from solution or the suspension of (1) sodium carbonate and SPC-D, (2) solution of sodium carbonate (optionally comprising SPC-D) or an aqueous solution of suspension and hydrogen peroxide, or solution of (3) sodium carbonate or suspension, solution of SPC-D or a solution of suspension and hydrogen peroxide.

It should be noted, for the sodium carbonate of coating layer or at least a portion of SPC-D, can also be incorporated to solid form, for example, with the form of fine powder or dust, preferably for example, at part drying step (b) (in whizzer) afterwards.This class solid carbonate is preferably to have d ₅₀the fine powder of < 0.2mm or the form of dust are included in step (c) process before, and this powder or dust are attached on still moist core particle.This can use a mixing auger transfer roller to make particulate granulating and realizing on this moist core particle.This fine materials can also be recycled to fluidised bed granulator, preferably near nozzle.

Another advantage of such embodiment is that the fine powder that occurs in these class methods of being everlasting or dust can be effectively and carry out easily recirculation.

In another embodiment, above method further comprises one or more additional encapsulation steps (c ') in step (c) and (d), (c "), (c ' "), ..., and/or in step (d) and (e), comprise one or more additional encapsulation steps (d '), (d "), (d ' "), ..., one, a plurality of or encapsulation steps that all these are additional all optionally the predrying step at least part of be associated (for example before it or with its simultaneously), wherein each additional encapsulation steps comprises with one or more additives and optionally with one or more, contains or the solution and/or the suspension that produce SPC-D is coated the particle obtaining from previous step, the composition of each coating layer is different from its one or more adjacent coating layer.

Preferably, one or more, more preferably all additional encapsulation steps and, if applicable, one or more, more preferably all drying step that they are optionally associated are all to carry out in one or more fluidized-bed reactors.

For additional coating layer or be optionally preferentially selected from the stablizer class of organic or inorganic for the additive of substrate coating layer, synergistic agent class, alkaline source class, weighting agent class, fluidity enhancers class and/or glass corrosion protective agent class, Sulfates such as basic metal or alkaline-earth metal, bicarbonate salts, carbonate, citric acid salt, phosphoric acid salt, borate family, silicates and/or chloride-based, together with their hydrate class, polycarboxylate, polyphosphonate, or poly-hydroxyl acrylic salt, in statu quo or with sour form, polyaminocarboxylic acid salt for example, picture EDTA or DTPA, or poly-amino methylene phosphonate class, picture EDTMPA, CDTMPA or DTPMPA, or hydrogenation alkylene phosphonic acids salt (hydroalkylenephosphonates), picture 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid salt, or be selected from the mixture of above material.

Be understood that, for screening step for the step of having mentioned (b) and (c) further or alternately, the method can be in step (c) and (d) and/or step (e) also comprise afterwards at least one screening step, for example,, so that the part of the undesirable size of collecting granules.

As an other aspect, the present invention relates to the coated sodium percarbonate granules obtaining by method described above.Therefore, this class particle comprises the core of a SPC-D, this core be via SPC-D the crystallization from the aqueous solution with separated from the aqueous solution and obtain; And a substrate coating layer that optionally comprises one or more additives containing SPC-D in described core, wherein, this substrate coating layer representative is greater than 20% by the weighing scale of SPC-D core particle; And at least one other coating layer that comprises sodium sulfate and sodium carbonate.

These particles can (preferably on described substrate coating layer) further comprise the one or more additional coating layer that contains SPC-D and/or one or more additives on described substrate coating layer and/or the described coating layer that is comprising sodium sulfate and sodium carbonate, and the composition of the coating layer that each is additional is different from its adjacent one or more coating layers.

As already mentioned, the coating layer that comprises sodium sulfate and sodium carbonate is coating and can applying by any known mode preferably, preferably in a fluidized-bed or mixing tank.In fact, in a preferred embodiment, this vitriol-carbonate coating layer can apply with two or more diverse ways in two or more stages of separating, these methods comprise the applying of a first protection package coating of the mixture that for example comprises solid sodium carbonate and sodium sulfate in a mixing tank, another encapsulation steps subsequently, this step is included in applying of a second protection package coating in fluidized-bed reactor, this the second protection package coating comprises the mixture of sodium carbonate and sodium sulfate, select these coating layers composition separately, so that it comprises 70: 30 to 30: 70 by weight, preferably 65: 35 to 35: 65, still more preferably 60: 40 to 40: 60, and most preferably the sodium sulfate of 57: 43 to 43: 57 compares sodium carbonate.

Another feature of coated sodium percarbonate granules is as already described above.

The present invention still has another aspect to relate to the coated sodium percarbonate granules described above purposes as SYNTHETIC OPTICAL WHITNER in detergent composition.

Therefore, the present invention still has another aspect to relate to the detergent composition that contains the coated sodium percarbonate granules of this class.

Brief Description Of Drawings

Fig. 1 illustrates size-grade distribution (psd) and utilizes the particle growth of higher fluid bed granulation layer/coating layer and the effect that span reduces,

Fig. 2 shows the contrast of bulk density (BD), span and coated level and duration of test runs, and has shown the span, bulk density (BD) of size-grade distribution (psd) and the relation between coated/granulating level,

Fig. 3 shows the per-cent of solvent time and the dissolving of three percarbonate samples measuring according to method described above, and

Fig. 4 shows the improvement of the stability in washing composition.

Example

Comparison example V1-V6: the coated test of carrying out with the mixture of 1: 1 of sodium sulfate, sodium carbonate and sodium sulfate and sodium carbonate

The sodium sulfate of V1.PCS+6%

The sodium sulfate of V2.PCS+9%

The sodium carbonate of V3.PCS+3% and 3% sodium sulfate

The sodium carbonate of V4.PCS+4.5% and 4.5% sodium sulfate

The sodium carbonate of V5.PCS+6%

The sodium carbonate of V6.PCS+9%

Coated program

Used the dry percarbonate produced with crystallization process as the raw material of each test.For these coated tests, used about 20kg to there is the sample of a homogenizing of the mean particle size of approximately 700 μ m.

For each test, the raw material of 2000g is put into Glatt moisture eliminator.Coated solution is respectively the metabisulfite solution of 25% and the sodium carbonate solution of 25%, and their mixture of 1: 1.Under the air themperature of approximately 110 ℃ and under the bed tempertaure of 50-55 ℃, will be coated spray solution to particle.After spraying the coated solution of calculated amount, product drying, until bed tempertaure arrives 70 ℃, is then removed and is distributed on a filter paper cooling to carry out by this material from moisture eliminator.

V1	The Na of PCS+6% 2SO 4
		Raw material	The percarbonate of 2000g
Coating	Na 2SO 4
		Coated level	6％
Quality	127.66g Na 2SO 4
		The concentration of coated solution	25％
The quality of coated solution	510.6g
		Air pressure	2.5 bar
Spray pressure	1.8 bar
		The lower temperature of bed	100-110℃
Temperature on bed	50-55℃
		The coated time	15 minutes
Time of drying	4 minutes

V2	The Na of PCS+9% 2SO 4
		Raw material	The percarbonate of 2000g
Coating	Na 2SO 4
		Coated level	9％
Quality	197.8g Na 2SO 4
		The concentration of coated solution	25％
The quality of coated solution	791.2g
		Air pressure	2.5 bar
Spray pressure	1.8 bar
		The lower temperature of bed	100-110℃
Temperature on bed	50-55℃
		The coated time	20 minutes
Time of drying	4 minutes

V3	PCS+ (3% Na 2CO 3+ 3% Na 2SO 4)
		Raw material	The percarbonate of 2000g
Coating	Na 2SO 4/Na 2CO 3
		Coated level	3％/3％
Quality	63.8g Na 2SO 4/63.8g Na 2CO 3
		The concentration of coated solution	25％
The quality of coated solution	510.6g
		Air pressure	2.5 bar
Spray pressure	1.8 bar
		The lower temperature of bed	100-110℃
Temperature on bed	50-55℃
		The coated time	13 minutes
Time of drying	4 minutes

V4	PCS+ (4.5% Na 2CO 3+ 4.5% Na 2SO 4)
		Raw material	The percarbonate of 2000g
Coating	Na 2SO 4/Na 2CO 3
		Coated level	4.5％/4.5％
Quality	98.9g Na 2SO 4/98.9g Na 2CO 3
		The concentration of coated solution	25％
The quality of coated solution	791.2g
		Air pressure	2.5 bar
Spray pressure	1.8 bar
		The lower temperature of bed	100-110℃
Temperature on bed	50-55℃
		The coated time	19 minutes
Time of drying	4 minutes

V5	The Na of PCS+6% 2CO 3
		Raw material	The percarbonate of 2000g
Coating	Na 2CO 3
		Coated level	6％
Quality	127.66g Na 2CO 3
		The concentration of coated solution	25％
The quality of coated solution	510.6g
		Air pressure	2.5 bar
Spray pressure	1.8 bar
		The lower temperature of bed	100-110℃
Temperature on bed	50-55℃
		The coated time	13 minutes
Time of drying	5 minutes

V6	The Na of PCS+9% 2CO 3
		Raw material	The percarbonate of 2000g
Coating	Na 2CO 3
		Coated level	9％
Quality	197.8g Na 2CO 3
		The concentration of coated solution	25％
The quality of coated solution	791.2g
		Air pressure	2.5 bar
Spray pressure	1.8 bar
		The lower temperature of bed	100-110℃
Temperature on bed	50-55℃
		The coated time	20 minutes
Time of drying	5 minutes

Table 1: analytical results

Coated sample is sieved and mps (mean particle size) closely similar.

The mensuration of the trace heat of the energy that above TAM value representation discharges in storage process, it is to pass through TAM

thermal Activity Monitor from Thermometric AB, (Sweden) measure.

Thermal output is measured in TAM at 40 ℃ and 50 ℃.Can find out, the coated sample of sodium sulfate demonstrates the highest thermal output.

By coated SPC-D sample and IECA ^*-substrate (15%PCS+85%IECA ^*-substrate) mix, and this preparation of 50g is placed in the carton box of lamination.Each rank has been prepared to 4 carton boxes.These carton boxes are stored to 8 weeks in climatic chamber under 32 ℃ and 80% relative humidity.Every 2 weeks by the AvOx of the contents melting of a carton box and titration remnants.

Surprisingly, the sample coated with using the pure sodium sulfate of same amount or pure sodium carbonate compared, and sodium sulfate and sodium carbonate mixture demonstrate the highest stability.

Comparison example V7 and example Ex1: the coated test of the particle that the PCS substrate carried out with 1: 1 mixture of sodium sulfate and sodium sulfate and sodium carbonate is coated

The sodium sulfate of V7.PCS+6%

The sodium carbonate of Ex1.PCS+3% and 3% sodium sulfate

Coated program

Used the dry SPC-D of producing with crystallization process as the raw material of each test; This raw material is coated with 25% percarbonate.The sample of the homogenizing of about 10kg is for these coated tests.Size-grade distribution is listed in table 2; The mean particle size of this sample is 718 μ m.

For each test, the raw material of 2000g is put into Glatt moisture eliminator.Coated solution is sprayed onto on particle under the bed tempertaure of the air themperature of approximately 110 ℃ and 50-55 ℃, until coated level reaches 6% (solid of=125g).After spraying the coated solution of calculated amount, product drying, until bed tempertaure reaches 83 ℃, is then removed and is distributed on a filter paper cooling to carry out by this material from moisture eliminator.

Coated solution:

Use two kinds of different mixtures as coated solution:

25% sodium sulfate is (V7) in water

25% the sodium carbonate+sodium sulfate of 1: 1 (Ex1) in water by weight

Table 2: analytical results

Analyze

Not coated PCS=precipitate

The Na2SO4 of coated PCS+6%

The Na2CO3 of Na2SO4+3% of coated PCS+3%

AVOX	％		13.65	13.66
Size-grade distribution
					＞1400μm	％		7	8.1	9
＞1250μm	％		5	5.1							5
					＞1000μm	％	14	13.9	14.8
＞850μm	％		8	7.8						8.2
					＞600μm	％	17	16.6	17.3
＞500μm		8	7.5	8
					＞425μm	％		10	9.1	8.8
＞300μm	％	22	22.6	21.2
					＞250μm	％		5	5.1	4.6
＞150μm	％		4	4.2							3
					＜150μm		0	0	0.1
MPS	μm	718	726	749
					Bulk density	Kg/l		1.113	1.109
Ampoule test (55 ℃) [Res.Avox]
					1 week	％		96	97
2 weeks	％		92	91
					3 weeks	％		93	91
5 weeks	％		88	92
					Humidity at 60 ℃	％		0.19	0.29
At IECA ＊In storage test (carton box of 50g)	Remaining AvOx
					2 weeks	％		86	89
4 weeks	％		69	77
					6 weeks	％		45	63

All samples (precipitate and product) show a comparable size-grade distribution, and the satisfactory stability of PCS is provided, because do not see the increase of fine materials.

When the percarbonate sample with coated is compared, can find out an obvious advantage with the PCS that mixes coating layer: after 6 weeks, the remaining Avox under 32 ℃ and 80% relative humidity is significantly higher with 63% to 45% result in the carton box of 50g.

By 1g sample being packed in the ampoule of a sealing and in baking oven, at 55 ℃, store and measure inherent stability.Remaining AvOx at 55 ℃ after 5 weeks is 92% (Ex1), apparently higher than 88% (V7) (this has been a goodish result).Therefore, these results have proved those contents relevant to Fig. 4 already described above.

Claims (16)

1. for the preparation of a method coated, that contain the particle of SPC-D, described method comprises:

(a) manufacturing step of the core particle that contains SPC-D, described manufacturing step comprise SPC-D from the aqueous solution crystallization with separated with the aqueous solution,

(b) at least part of drying step that contains the core particle of SPC-D described in,

(c) encapsulation steps, described step comprise with one or more contain or produce the solution of SPC-D and/or suspension and optionally one or more additives on the core particle so obtaining, apply substrate coating layer,

(d) encapsulation steps, described step comprise with sodium sulfate and sodium carbonate and optionally one or more additives on the particle from previous step, apply other coating layer, and

(e) described drying step coated, that contain the particle of SPC-D,

Wherein, step (c) and optionally step (d) and/or step (e) are carried out in fluidized-bed reactor, and the substrate coating layer of step (c) accounts for by the weighing scale of the described core particle containing SPC-D and is greater than 20%.

2. method according to claim 1, wherein said solution and/or the suspension that contains or produce SPC-D is selected from solution or the suspension of (1) sodium carbonate and SPC-D, (2) optionally comprise sodium carbonate solution or suspension and the superoxol of SPC-D, or (3) sodium carbonate solution or suspension, SPC-D solution or suspension and superoxol.

3. method according to claim 1 and 2, further between step (c) and step (d) and/or between step (d) and step (e), comprising one or more additional encapsulation steps, one, the encapsulation steps that a plurality of or all these are additional are optionally associated with at least part of drying step, and wherein each additional encapsulation steps comprises with one or more additives and optionally one or more contain or the solution and/or the suspension that produce SPC-D is coated the particle from previous step.

4. method according to claim 3, one of them, a plurality of or all additional encapsulation steps and, if words applicatory, one, a plurality of or all their drying step being optionally associated carry out in one or more fluidized-bed reactors.

5. method according to claim 1 and 2, wherein the coating layer in step (d) is coating, and sodium sulfate is 70: 30 to 30: 70 by weight than sodium carbonate.

6. method according to claim 1 and 2, wherein said additive is selected from: organic or inorganic stablizer, synergistic agent, alkali source, weighting agent, fluidity enhancers and/or glass corrosion protective agent, or be selected from the mixture of above material.

7. method according to claim 1 and 2, wherein said coated particle has from the mean particle size of 300 μ m to 1600 μ m.

8. method according to claim 1 and 2, further between step (b) and step (c) and/or between step (c) and step (d) and/or step (e) comprise afterwards at least one screening step.

9. by the coated sodium percarbonate granules obtaining according to the method described in any one in claim 1 to 7.

10. particle according to claim 9, comprises the core containing SPC-D, and described core is by SPC-D crystallization obtain separated with the aqueous solution from the aqueous solution; .And the substrate coating layer containing SPC-D in described core, described substrate coating layer optionally comprises one or more additives, and wherein said substrate coating layer accounts for by the weighing scale of described SPC-D core particle and is greater than 20%; And at least one other coating layer that comprises sodium sulfate and sodium carbonate.

11. particles according to claim 10, comprise one or more additional packet coating that contain SPC-D and/or one or more additives.

12. according to the particle described in claim 10 or 11, and wherein said additive is selected from: organic or inorganic stablizer, synergistic agent, alkali source, weighting agent, fluidity enhancers and/or glass corrosion protective agent, or be selected from the mixture of above material.

13. according to the particle described in claim 10 or 11, and the wherein said coating layer that comprises sodium sulfate and sodium carbonate is that coating and sodium sulfate are 70: 30 to 30: 70 by weight than sodium carbonate.

14. according to the particle described in claim 10 or 11, has from the mean particle size of 300 μ m to 1600 μ m.

15. according to the purposes as SYNTHETIC OPTICAL WHITNER in detergent composition of the coated sodium percarbonate granules described in any one in claim 9 to 14.

16. detergent composition, comprise the sodium percarbonate granules described in any one in claim 9 to 14.

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