Note: Descriptions are shown in the official language in which they were submitted.
2020~
Stabilized Sodium Percarbonate Composition
Background of the Invention
The present invention relates to a stabilized sodium
percarbonate composition, particularly a stabilized sodium
percarbonate composition suitable for use as a bleaching agent
in detergents, etc.
Sodium percarbonate is generally used widely as a
bleaching agent, a detergent, or a sterilizer. Sodium
percarbonate as a bleaching agent is superior in solubility at
low temperatures, exhibits a high bleaching effect, and is a
stable compound in an ordinary perserved state. However,
~odium percarbonate is disadvantageous in that it is unstable
when preserved in a high humidity condition or when
incorporated in a detergent. As a household detergent, a
product containing a predetermined certain amount of sodium
percarbonate as a bleaching agent is particularly preferred.
When incorporated in a detergent, however, sodium percarbonate
loses its stability upon contact with a zeolite which is used
ac a builder or with water contained in a very small amount in
the detergent, resulting in that not only the sodium
percarbonate no longer exhibits the bleaching effect but also
there is fear of the detergent losing its effect. Various
proposals have heretofore been made for solving these problems.
For example in Japanese Patent Publication No. 56167/1988 there
is disclosed a method wherein sodium percarbonate is coated
with magnesium sulfonate or magnesium salt of sulfuric ester;
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in Japanese Patent Publication No. 57362/1988there is disclosed
a method wherein sodium percarbonate is coated with such
magnesium salt plus sulfate or hydrochloride of an alkali or
alkaline earth metal; in Japanese Patent Laid-Open No.
118606/1085 there is disclosed a method wherein sodium
percarbonate is coated with boric acid or a partially
neutralized borate and a water repellent: in Japanese Patent
Laid-Open No. 194000/1984 a method wherein sodium percarbonate
is coated with a borate and a magnesium compound; and in
Japanese Patent Laid-Open No. 129500/1975 a method wherein
sodium percarbonate is coated with a mixture of a surfactant
and a water-insoluble compound which is compatible with the
surfactant. All of these methods intend to prevent sodium
percarbonate rom coming into contract with detergent
lngredients to stabilize it by coating it with specific
chemical substances. According to these conventional methods,
however, when the sodium percarbonate thus coated is preserved
in a high humidity condition or when incorporated in a
detergent, the stabilization effect is not attained at all to a
satisfactory extent in practical use.
- It is the object of the present invention to solve
the above-mentioned problem. The present inventors found that
the aforesaid problem which had not been solved by the prior
art could be overcome by incorporating in sodium percarbonate a
mono- or dicarboxylic acid having not less than four carbon
atoms or a salt thereof and a sulfate, nitrate or silicate of
an alkali metal or alkaline earth metal. In this way we
reached the present invention.
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Summary of the Invention
The present invention resides in a composition
comprising sodium percarbonate and a stabilizer, the stabilizer
consisting essentially of:
(a) at least one compound selected from the group consisting
of mono- and dicarboxylic acids each having not less than four
carbon atoms, and salts thereof; and
(bO at least one compound selected from the group consisting
of sulfates, nitrates and silicates of alkali metals and
alkaline earth metals.
This sodium percarbonate composition, as compared with the
conventional sodium percarbonate, is remarkably improved in its
stability during preservation in a high humidity condition or
when incorporated in a detergent.
Detailed Description of the Invention
Examples of mono and dicarboxylic acids each having
not less than four carbon atoms which may be used in the
present invention include saturated or unsaturated aliphatic,
alicyclic or aromatic mono- or dicarboxylic acids having 4 to 20
carbon atoms. More concrete examples are butyric acid,
isobutyric acid, valeric acid, caproic acid, caprylic acid,
capric acid, lauric acid, myristic acid, palmitic acid, stearic
acid, isostearic acid, arachic acid, behenic acid, lignoceric
acid, cyclohexanecarboxylic acid, crotonic acid, 2-methylacrylic
acid, sorbic acid, 2,4-pentadienoic acid, zoomaric acid,
linolenic acid, linoleic acid, recinoleic acid, gadoleic acid,
erucic acid, selacholeic acid, benzoic acid, diphenylacetic
acid, toluic acid, p-t-butylbenzoic acid, phenylacetic acid,
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benzoylbenzoic acid, ethylbenzoic acid, 2,3,5-trimethylbenzoic
acid, d-naphthoic acid, B-naphthoic acid, 2-methylnaphthoic
acid, sebacic acid, undecanoic acid, dodecane-dicarboxylic
acid, brassylic acid, detradecane-dicarboxylic acid, thapsinic
acid, itaconic acid, muconic acid, naphthenic acid, beef tallow
fatty acid, horse fat fatty acid, mutton tallow fatty acid,
lard fatty acid, coconut oil fatty acid, palm oil fatty acid,
palm kernel oil fatty acid, soybean oil fatty acid, linseed oil
fatty acid, castor oil fatty acid, rice bran oil fatty acid,
rape oil fatty acid, and hydrogenated such fatty acids.
Examples of salts of mono- and dicarboxylic acids
each having not less than four carbon atoms which may be used
in the present invention include sodium salts, potassium salts,
magnesium salts and calcium salts of the C4 or more mono- or
dicarboxylic acids examplified above.
Examples of sulfates, nitrates and silicates of
alkali metals and alkaline earth metals which may be used in
the present invention include sodium sulfate, potassium
sulfate, magnesium sulfate, sodium nitrate, potassium nitrate,
magneslum nitrate, calcium nitrate, sodium silicate (Nos. 1, 2
and 3), sodium metasilicate, sodium orthosilicate, and
potassium silicate.
In the stabilizer used in the present invention, even
if at least one compound selected from the group (A) or at
least one compound selected from the group (B) is incorporated
each alone in sodium percarbonate, there will not be obtained a
satisfactory effect of stabilization. Only when both compounds
are used together ther~ is obtained a satis~actory effect.
2020~89
It is preferable that the stabilizer components (A)
and (B~ in the present invention be used each in an amount of
0.5 to 20 wt~. If the amount thereof is smaller than O.S wt%,
there will not be obtained a satisfactory effect, while if the
amount thereof is larger than 20 wt~, the effective oxygen
concentration will be decreased more than necessary although a
satisfactory effect of stabilization will be obtained. More
preferably, the stabilizer components (A) and (B) are used each
in an amount o 2 to lO wt~.
For preparing the composition of the present
invention there may be adopted any method if only it permits
uniform dispersion or incorporation of the stabilizer
components (A) and (B) in sodium percarbonate. For example,
the composition of the present invention can be prepared by
mixing the compounds (A) and (B) with wet crystals obtained in
a crystallization step and then granulating the resulting
mixture. Or it can be prepared by dissolving the stabilizer
components in water or an organic solvent and spraying the
resulting solution to flowing crystals or granules of sodium
percarbonate followed by drying. A solution containing both
compounds (A) and (B) may be sprayed in a single step, or
separate solutions prepared using the compounds (A) and (B)
respectively may be sprayed in two separate steps. Or one of
the compound~ (A) and (B) may be added at the time of
granulation, while the other is sprayed as a solution. There
also may be used conventional additives for sodium percarbonate
such as stabilizers other than the one used in the present
invention as well as granulation binders.
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Examples
The present invention will be described below in more
detail in terms of working Examples of the invention and
Comparative Examples. But it is to be understood that the
invention is not limited thereto.
Examples l - 29
Sodium carbonate and hydrogen peroxide were reacted
together in an aqueous solution and the resulting crystals were
separated by centrifugal filtration. Then, the resulting
crystals of sodium percarbonate in a wet condition were mixed
with a predetermined amount of each of the stabilizer
components (A) shown in Table l in accordance with the
correcponding composition ratio set forth also in the same
table. The resulting mixture was extrusionwise granulated by
means of a granulator equipped with a 1.0 mm mesh wire gauze,
followed by drylng. 200 g of the granules thus obtained were
fed into a rotary vacuum dryer equipped with a spray coated and
a 10-25% aqueous solution of the corresponding stabilizer
component (B) shown in Table l was sprayed to the granules
little by little while heating was made to 70C under reduced
pre~sure in accordance with the corresponding compsition ratio
~et forth in the same table. After termination of the
spraying, the composition thus obtained was dried for 20
minute~. In this way there were prepared sodium percarbonate
compo~itions in accordance with the composition ratios
described in Table l, which compositions were found to range in
effective oxygen concentration from 12.5% to 13.5~. Then, the
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compositions were each mixed 2 g with 2 g of a powdered zeolite
for detergent intimately and the resulting mixtures were
allowed to stand for 48 hours under the conditions of 50C and
a relative humidity of 80~, then determined for residual
effective oxygen concentrations, from which the respective
stabilities were calculated. The results are as set out in
Table 1. The determination of effective oxygen concentration
was performed according to an iodometric titration method. For
comparison purpose, the same test was conducted also with
respect to the use of sodium percarbonate not containing any
stabilizer and the use of each stabilizer component alone, and
the results obtained are showing as Comparative Examples in
Table 1.
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Ex. Composition Ratio (~)
Sodium Stabilizer Stabilizer Stability
No. Percarbonate Component (A) Component (B) (~)
,
: 1 90 caproic Acid 5 magnesium 5 69
2 90 ~ 5 " 5 71
3 90 cyclohexane- " 5 70
carboxylic
-~; acid 5
4 90 lauric acid 5 magnesium 5 73
' ; 5 90 myristic acid 5 sodium 73
- sulfate 5
6 90 palmitic acid 5 n 5 75
7 90 stearic acid 5 potassium 70
sultate 5
- 8 90 behenic acid 5 sodium 69
nitrate 5
9 90 linolenic acid 5 magnesium 72
nitrate 5
" 5 " 5 75
' 11 90 recinoleic magnesium 5 76
acid 5 sulfate
. - 12 90 p-toluic acid 5 " 5 78
13 90 phenylacetic " 5 79
acid 5
14 92 beef tallow " 3 73
fatty acid 5
: , 15 92 horse fat " 3 72
fatty acid 5
~:' 16 94 mutton tallow sodium 70
fatty acid 5 silicate
. ~No.3)
17 93 lard fatty potassium 72
. acid 5 silicate 2
18 90 coconut oil sodium 75
fatty acid 5 sulfate 5
! 19 90 palm kernel " 5 75
: i oil fatty
acid 5
soybean oil " 5 77
fatty acid 5
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20~205~89~cdble 1 2 of 2
Sodium Stabilizer Stabilizer gtabllity
No. Percarbonate Component (A) Componen~ lB) (%)
21 94 linseed oil sodium 73
fatty acid 5 silicate
(No.3)
22 94 rice bran " 1 75
: oil fatty
acid 5
23 94 hydrogenated " 1 76
beef tallow
fatty acid 5
24 92 hydrogenated magnesium 77
horse fat sulfate 3
fatty acid S
92 naphthenic " 3 72
acid (~125) 5
26 92 sodium " 3 77
oleate 5
27 90 potassium sodium 73
oleate 5 sulfate 5
28 90 magnesium " 5 73
oleate 5
29 90 calcium " 5 74
oleate 5
Comp. Ex.
1 100 . 20
2 95 magnesium 5 25
sulfate
3 99 - sodium 1 33
silicate
(No.3)
4 95 beef tallow 5 40
fatty acid
sodium 5 39
oleate
6 99.4 beef tallow 0.3 magnesium 0.3 45
fatty acid sulfate
7 99.4 p-toluic acid 0.3 sodium 0.3 43
sulfate
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Examples 30 - 49
200 g of 16 to 80 mesh granules of dried sodium
percarbonate obtained by extrusive granulation were fed into a
rotary vacuum dryer equipped with a spray coater and a 10-255
aqueous solution of each of the stabilizer components (B) shown
in Table 2 was sprayed to the granules little by little while
heating was made to 70C under reduced pressure until a
predetermined amount thereof was incorporated in the granules.
Then, a 10-30% solution in ethanol of each of the stabilizer
components (A) shown in the same table was sprayed in the same
manner as above until a predetermined amount thereof was
incorporated in the granules. After termination of the
spraying, the composition thus obtained was dried for 10
minutes. In this way there were prepared sodium percarbonate
compositionq in accordance with the composition ratios
de~cribed in Table 2, which compositions were found to range in
effective oxygen concentration from 12.0% to 13.5%. Then, the
compositions were determined for stability in the same way as
ln Examples 1-29. The results are as set forth in Table 2.
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Table 2 1 of 2
Ex. Composition Ratio (%)
Sodium Stabilizer Stabilizer Stability
No. Percarbonate Component (A) Component (B) ~ (%)
92 crotonic acid 5 magnesium 72
sulfate 3
31 92 2-methylacrylic ~"
aci~ 5 " 3 73
32 92 sorbic acid 5 " 3 70
33 90 d-naphthoic sodium
acid 5 sulfate 5 77
34 90 sebacic acid 5 " 5 70
didecane- " 5 80
dicarboxylic
acid 5
36 90 tetradecane- " 5 81
dicarboxylic
acid 5
37 90 muconic acid 5 " 5 72
38 90 beef tallow magnesium
fatty acid 5 sulfate 5 81
39 90 " 5sodium 76
sulfate 5
-93 " 5sodium 75
silicate
(No.2) 2
41 93 " 5sodium 72
sulfate 2
42 92 " 5magnesium 70
nitrate 3
43 91.5 /beef tallow /sodium 80
soda soap 80% silicate
mixture coconut oil 5 (No.3) 0.5
~oda soap 20% ~sodium
sulfate 3
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Table 2
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Sodium Stabilizer StabilizerStability
No. Percarbonate component (A) Component (B) (~)
44 92.5 benzoic acid 1 sodium 83
/ silicate
naphthenic (No.3) 0.5
acid (#125) 1
sodium
beef tallow sulfate 3
~fatty acid 2
94 benzoic acid 1 magnesium 69
sulfate 5
46 90 " 5 " 5 79
47 85 " 10 " 5 85 .
48 98 " 0.5 sodium 67
sulfate
sodium
silicate
(No-3) 0.5
49 99 beef tallow sodium 0.5 63
fatty acid 0.5 silicate
(No.3)
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