CA1128292A - Stabilized red phosphorus and process for its manufacture - Google Patents
Stabilized red phosphorus and process for its manufactureInfo
- Publication number
- CA1128292A CA1128292A CA364,042A CA364042A CA1128292A CA 1128292 A CA1128292 A CA 1128292A CA 364042 A CA364042 A CA 364042A CA 1128292 A CA1128292 A CA 1128292A
- Authority
- CA
- Canada
- Prior art keywords
- phosphorus
- epoxide resin
- water
- red phosphorus
- epoxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/003—Phosphorus
- C01B25/006—Stabilisation
Abstract
ABSTRACT OF THE DISCLOSURE
The invention relates to stabilized, pulverulent red phosphorus, consisting of phosphorus particles having a particle size of at most about 2 mm, and an oxidation stabilizer which envelops the phosphorus particles in the form of a thin layer , wherein a) The oxidation stabilizer is a combination of aluminum hydroxide and is a combination of system having an epoxide equivalent weight of about 170 to 500.
b) the total amount of the oxidation stabilizer is 0.1-5 % by weight, based on the amount of red phosphorus, and c) the proportion of aluminum hydroxide is about 0.01 to 3 % by weight, and the proportion of epoxide resin is about 0.09 to 4.99% by weight, in each case based on the amount of the red phos-phorus.
The invention relates to stabilized, pulverulent red phosphorus, consisting of phosphorus particles having a particle size of at most about 2 mm, and an oxidation stabilizer which envelops the phosphorus particles in the form of a thin layer , wherein a) The oxidation stabilizer is a combination of aluminum hydroxide and is a combination of system having an epoxide equivalent weight of about 170 to 500.
b) the total amount of the oxidation stabilizer is 0.1-5 % by weight, based on the amount of red phosphorus, and c) the proportion of aluminum hydroxide is about 0.01 to 3 % by weight, and the proportion of epoxide resin is about 0.09 to 4.99% by weight, in each case based on the amount of the red phos-phorus.
Description
~8~
HOE 79/H 04~
The in~ention relates to stabilized, pulverulent red phosphorus, the surface o~ the red phosphorus par-ticles being covered with a thin layer o~ oxidationstabilizers, and to a process for its manufacture.
It has been described that red phosphorus undergoes a chemical surface reaction which involves oxidation and disproportionation with the resultant formation of various acids of phosphorus of oxidation levels ~1 to +5, and phosphine.
As described in Gmelins Handbuch der anorganischen Chemie (Gmelins Handbook of Inorganic Chemistry), 8th Edition (1964), Volume "Phosphorus", part B, page 83, Verlag Chemie, ~e m heim/Bergstrasse, aluminum hydroxide should conveniently be used for stabilizing red phosphorus.
The aluminum hydroxide is precipitated onto the phosphorus particles by successive addition of aqueous 10% strength solutions of sodium hydrogen carbonate and aluminum sulfats with a temperature of 55 to 60 C. Next, the aqueous sus-pension is filtered and the ~ilter residue is dried~ ~his procedure is not ~ully satisfactory inasmuch as undesirably large amounts of aluminum hydroxide have to be used so as to produce a satisfactory stabilizing effect. Needless to say, this lS a procedure contaminating phosphorus to an extent unacceptable for a wide variety of uses.
Another process for stabilizing red phosphorus, as described in U.S. Patent Speci.fication 2,359,243, provides ... ,.......... . : ~ ' Z9~
for red phosphorus to be suspended in an aqueous 0.04-N-; ~ solution of sodium aluminate, ~or air to be passed for 10 hours through the suspension, at 85 - 90 C, ~or the whole to be filtered, washed with hot water and dried under vacuum.
Finally, it is known from U.SO Patent Specification
HOE 79/H 04~
The in~ention relates to stabilized, pulverulent red phosphorus, the surface o~ the red phosphorus par-ticles being covered with a thin layer o~ oxidationstabilizers, and to a process for its manufacture.
It has been described that red phosphorus undergoes a chemical surface reaction which involves oxidation and disproportionation with the resultant formation of various acids of phosphorus of oxidation levels ~1 to +5, and phosphine.
As described in Gmelins Handbuch der anorganischen Chemie (Gmelins Handbook of Inorganic Chemistry), 8th Edition (1964), Volume "Phosphorus", part B, page 83, Verlag Chemie, ~e m heim/Bergstrasse, aluminum hydroxide should conveniently be used for stabilizing red phosphorus.
The aluminum hydroxide is precipitated onto the phosphorus particles by successive addition of aqueous 10% strength solutions of sodium hydrogen carbonate and aluminum sulfats with a temperature of 55 to 60 C. Next, the aqueous sus-pension is filtered and the ~ilter residue is dried~ ~his procedure is not ~ully satisfactory inasmuch as undesirably large amounts of aluminum hydroxide have to be used so as to produce a satisfactory stabilizing effect. Needless to say, this lS a procedure contaminating phosphorus to an extent unacceptable for a wide variety of uses.
Another process for stabilizing red phosphorus, as described in U.S. Patent Speci.fication 2,359,243, provides ... ,.......... . : ~ ' Z9~
for red phosphorus to be suspended in an aqueous 0.04-N-; ~ solution of sodium aluminate, ~or air to be passed for 10 hours through the suspension, at 85 - 90 C, ~or the whole to be filtered, washed with hot water and dried under vacuum.
Finally, it is known from U.SO Patent Specification
2,635,95~ that apart from aluminum hydroxide, zinc hydroxide or magnesium hydroxide may also be used to stabilize red phosphorus.
The last-me~tioned known processes do also not permit red phosphorus to be satisfacto~nystabilized to oxidation with a minimum of stabilizer. In fact, the oxidation stabilizers described heretoforepresent an unsatisfactory thermal stability, water being split off at elevated tem-peratures. With respect to plastics which are to be pro-cessed on an extruder and have red phosphorus as a flame-proofing agent incorporated therein, which in turn con-tains an oxidation stabilizer, it i~ generally accepted that the oxidation stabilizer should present thermal stability in the absence of any tendency to split off water or to undergo decomposition, even at temperatures above 300 C.
This is a disadvantageous effect which has also been encountered in the stabilization process described in German Of~enlegungsschrift 2,6229296. In that process, the stabilizing effect is achieved by precipitating small amounts of metal salts of various acid orthophosphoric acid esters onto the sur~ace of the red phosphorus.
..
112~3292 The orthophosphoric acid metal salts suggested for use as stabilizers in German Offenlegungsschri~t 2 631 532, produce material which has an inadequate stability to oxidation for a variety of uses.
The metal salts of phosphonic acids and phosphinic acids (cf. German Offenlegungsschrift 2 ~47 093 and German Offenlegungsschrift 2 632 296 respectively) ad-mittedly produce good thermal stability and oxidation stability, but they are relatively expensive products and have to be used in proportions as high as 3 - 5 %
by weight.
As described in German Patent Specification 2 655 739 and German Offenlegungsschrift 2 705 042 it is possible for the stability to oxidation of red phosphorus to be effectively improved by applying a thin layer of a melamine/
formaldehyde resin to the surface of the red phosphorus particles. However, these stabilizers prove unsatisfactory inasmuch as the stabilizing effect is largely lost if the stabilized phospho~us is stored under tropical conditions, that is to say at ~0 C and 100 % relative atmospheric moisture, such as are simulated in the modified Indian Standard Test (I~ 2012 - 1961~.
Finally, German Patent Specification 2 625 674 dis-closes an agent which permits the use of red phosphorus in plastics, without hydrogen phosphide being liberated as a result of the processing temperature of the plast1c and of the presence of small amounts of water or moisture in the plastic to be processed. The agent comprises epoxide :` ~
IlZ~29Z
resins, which envelop the phosphorus particles, the resins being used in proportions of 5 - 50 Yo by weigh~
We have now unexpectedly found that the stabilization of red phosphorus can be improved by replacing the epo~ide resin by a mixture of an epoxide resin and aluminum hydroxide, of which a thin layer is applied to the sur~ace of the red phosphorus.
The present invention relates more particularly to sta-bilized, pulverulent red phosphorus, consisting of phosphorus particles having a particle size of at most about 2 mm, and an oxidation stabilizer envelopping the phosphorus particles in the form of a thin layer, the phosphorus containing a) as the oxidation stabilizer a combination of aluminum hydroxide and a hardened epoxide resin system having an epoxide equivalent weight of about 170 to 500, b) the oxidation stabilizer in a total proportion of 0.1 - 5 % by weight, based on the quantity of red phosphorus, and c) the aluminum hydroxide in the red phosphorus in a proportion of about 0.01 to ~ % by weight, and the epoxide resin in a proportion of about 0.09 to 4.99 %
by weight, in each case based on the quantity of red phosphorus.
A preferred embodiment of the invention pro~ides for the epoxide resin to be an e~oxide~phenolic resin, such as, for example, the reaction product of epichlorohydrin and 2,2-bis-(4~hydroxyphenyl)-propane (bisphenol A) or an epoxide resin ester.
~i ~ ` 112~329;~
The invention also relates to a process for the manufacture of stabilized pulverulent red phosphorus, which comprises introducing a water~soluble aluminum salt and an aqueous or alcoholic solution or dispersion o~ an epoxide resin and of a hardener into an aqueous suspension of the red phosphorus, establishing a pH-value within the range about 5 to 9, stirring the mixture for 1 to 3 hours at a temperature of 20 to 90 C, with pre-cipitation of the aluminum hydroxide and hardening of the epoxide resin, and filtering the s-tabilized phosphorus and finally drying it at an elevated temperature.
Further preferred features of the present invention provide for the resin component to comprise:
a) liquid epoxide resinswhich combine a very low to medium viscosity with a 100 % reactivity and are hardenable with water-soluble or water-emulsi-fiable hardeners, or b) unmodified, liquid 100 % reactive reaction products of epichlorohydrin and bisphenol A, which are hardenable with water-soluble or water-emulsifiable hardeners, or c) an aqueous epoxide-phenolic resin dispersion or water-emuisifiable 9 100 % reactive epoxide resin ester, either of which is hardenable with water-soluble or water-emulsifiable hardeners.
The epoxide resins are hardened in a conventional manner, for example in an queous phase at a temperature of 20 - 90 C and while maintaining a pH value o~ the ... . .. . .. . . .. . . . . . . . . .
~Z82~Z
aqueous phase of 5 - 9; suitable hardeners include water-soluble, internally modified pol~mines or water-emulsifiable polyaminoamides.
The red phosphorus stabilized in accordance with the invention, and the process for its manu~acture, com-pare favorably with the prior art inasmuch as the stabilizer is thermally stable and is furthermore so effective that even the addition of very small amounts results in red phosphorus of adequate stability for a wide variety of uses.
The invention is illustrated by the ~ollowing examples.
500 ml of an aqueous phosphorus suspension containing 250 g of pulverulent red phosphorus were diluted with 250 ml o~ water, brought to a p:~ value of 4 by adding 5 % strength H2S04, and warmed to 60 C. After dropwise addition o~ a solution of 5.3 g o~ A12(S04)3 18 H20 in 50 ml o~ water, and of an emulsion of 1.0 g of a liquid, very low-viscosity epoxide resin A ~ eckopox EP 128 from Hoechst Aktiengesellschaft, Frankfurt/Main) having an epoxide equivalent weight of about 200 and a density, at 25 C, of 1.12 g/ml, and 1.0 g of a water-soluble, internally modified aliphatic polyamine hardener ~ eckopox VEH 21~0 from Hoechst Aktiengesellschaft, Frankfurt~Main), having an H-equivalent w~ght of about 200 and a density, at 25 C, of 1.10 g/ml, in 50 ml of w.~ter, the suspension was brought to a pH-value o~ 5 by adding 5 % strength by weight sodium hydro~ide solution. Next 9 the suspension was stirred for 1 hour at 60 C, and then brought to a pH-value of 7 with 5 % strengt~
llZ8Z9~
by weight sodium hydroxide solution. A~ter stirring for a further 15 minutes, t~e mixture was ~lltered and the filter residue was washed wi-th wa-ter and dried in a s~rearn of nitrogen at 100 C. The proportion o~ aluminum hydroxide in the dried red phosphorus was 0.46 ~0 by weight and the proportion of epoxide resin was 0.68 % by ~eight, based on the amount of red phosphorus employed.
The oxidation stability of the red phosphorus stabilized as described above was tested in accordance with the two test procedures described ~elow.
Test 1:
450 ml o~ water and 1 g of the pretreated red phos-phorus were introduced into a three-necked flask equipped with a gas inlet tube, thermometer, reflux condenser and magnetic stirrer, the mixture was warmed to 80 C and 10 litres of oxygen per hour were passed into the mixture, under agitation. The gas mixture which escaped via the re-flux condenser and consisted of oxygen and hydrogen phosphide which had been produced, together with acids o~ phosphorus of various oxidation levels, by disproportionation o~ the red phosphorus, was led through two washbottles which were arranged one downstream o~ the other, and which each con-tained 100 ml of a 2.5 % strength by weight aqueous mercury (II)chloride solu~ion~
In this method, the phosphine reacted with the mercury~II) chloride in accordance with the followin~
equation:
PH3 + 3 HgCl2 ~ P(HgCl)3 ~ ~ HCl . .. . . . .. ..
The amount of oxo-acids of phosphorus contained in the aqueous suspension of the red phosphorus~ and ~he hydrochloric acid contained in the gas washbottlcs, scrtred as an index of the oxidation stability of the red phos-phorus. The contents of phosphorus acids and of hydrochloricacid were determined titrimetrically. The values calculated therefrom are shown in Table 1) columns A and B. Column A
sh~ws the amount of PH~ (mg o~ PH3 per gram of phosphorus per hour) formed during oxidation of the red phosphorus.
The values in column B are index o~ the acidity of the aqueous phosphorus-containing suspension, resulting from the formation of phosphorus acids during oxidation of the phosphorus(mg o~ KOH per gram of phosphorus per hour).
Test 2:
The oxidation stability was determined on the basis of Indian Standard "Specification of red phosphorus"
(IS 2012 - 1961).
For this purpose, 5.0 g of red phosphorus was weighed out into a crystallizing dish of 50 mm diameter and the dish was stored in a closed glass vessel for 168 hours at 5~ C
and 100 % relative atmospheric humidity. The phosphine thereby formed was expelled from the glass vessel by means of a stream of air (10 l/h) and caused to react with 2.5 %
strength by weight mercury(II) chloride solution in a gas washbottle, and the amount of hydrochloric acid thereby formed was determined titrimetrically.
To determine the content of the various o~o-acids of phosphorus, the sample of phosphorus was trans~erred into a 250 ml beaker, 120 ml of water and 40 ml of _ g _ ~12~ 3Z
n-propanol were added, and the mixture was heated to the boil for 10 minutes and then filtered. The quantitative analytical determination of the oxo-acids in the ~ rate was then carried out by titration with 0.1 N NaOH up to the equivalent point for the 2nd titration stage, at pH 9.5.
The values calculated therefrom are shown in Table 2.
The procedure followed was analogous to Example 1, but 10.6 g of aluminum sulfate were used. The proportion of aluminum hydroxide in the dried red phosphorus was 0.92 % by weight and the proportion of epoxide resin was 0.67 % by weight. The values of-the oxidation stability o~ the red phosphorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE_~
The procedure followed was analogous to Example 1, but 1.1 g o~ aluminum sulfate were used. The proportion of aluminum hydroxide in the dried red phosphorus was 0.10 % by weight and the proportion of epoxide resin was 0.72 % by weight. The values of the oxidation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
The procedure followed was analogous to Example 1, but 1.1 g o~ aluminum sul~a~e, 0.5 g o~ epoxide resin A and 0.5 g of hardener were used. The proportion o~
aluminum hydroxide in the dried red phosphorus was 0.11 %
~L2~2~Z
by weight and the proportion of epoxide resin was 0.37 ~o by weight. The values of the oxidation stability of the red phosphorus t~eated in this ~anner are shown in Tables 1 and 2.
The procedure was analogous to Example 1, but 1.0 g of a liquid, very low-viscosity epoxide resin B (--Beckopox VEP 22 from Hoechst Aktiengesellschaft, Frankfurt/Main) with an epoxide equivalent weight of about 195 and a density, at 25 C, of 1.11 g/ml, and 1 D O g of the hardener of Example 1 were used. The proportion of aluminum hydroxide in the dried red phosphorus was 0.46 % by weight and the proportion of epoxide resin was 0.67 ~ by weight.
The values of the 02idation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE_6 The procedure was analogous to Example 5, but 10.6 g of aluminum sulfate were used. The proportion of aluminum hydroxide in the dried red phosphorus was 0.94 % by weight and the proportion of epoxide resin was 0.68 % by weight.
The values of the oxidation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
The procedure was analogous to Example 5 t but 1.1 g of aluminum sulfate was used. The pro-portion of aluminum hydroxide in the dried red phosphorus was 0.11 % by weight and the proportion of ~oxide resin was 0.74 % by weight. The values of the oxidation stability 9z of the red phosphorus treated in this manner are shown in Tables 1 and 2.
. . _ The procedure was analogous to Example 5, but 1.1 g o~ aluminum sulfate, 0.5 g of epoxide resin B and 0.5 g of hardener were used. The proportion of aluminum hydroxde in the dried red phosphorus was 0.11 /0 by weight and the proportion of epoxide resin was 0.~6 % by weight. The values of the oxidation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE 9 (Comparative Example) The procedure was analogous to Example 1 but no aluminum sulfate was used. The proportion of epoxide resin in the dried red phosphours was 0.74 % by weight.
The values of the oxidation stability of the red phos-phorus treated in this manner are shown în Tables 1 and 2.
EXAMPLE 10 (Comparative Example) The procedure was analogous to Example 5, but no aluminum sulfate was used. The proportion of epoxide resin in the dried red phosphorus was 0~70 % by weight.
The values of the oxidation stability o~ the red phos-phorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE 11 (Comparative Example) The procedure was analogous to Example 1, but neither epoxide resin nor epoxide hardener was employed. The pro-portion o~ aluminum hydroxide in the dried red phosphorus was 0.48 % by weight. The values of the oxidation stability _ 12 -9~
o~ the red phosphorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE 12 (Comparative Example) The procedure was analogous to Example 2, but neither epoxide resin nor epoxide hardener was employed. The pro-portion of aluminum hydroxide in the dried red phosphorus was 0.92 % by weight. The values of the oxidation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
It follows from the data in Tables 1 and 2 that the aluminum hydroxide/epoxide resin stabilizer according to the invention is capable of achieving an improved stabilizing effect, with a smaller total amo~nt of stabilizer, than with -the use of aluminum hydroxide or epoxide resin alone.
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The last-me~tioned known processes do also not permit red phosphorus to be satisfacto~nystabilized to oxidation with a minimum of stabilizer. In fact, the oxidation stabilizers described heretoforepresent an unsatisfactory thermal stability, water being split off at elevated tem-peratures. With respect to plastics which are to be pro-cessed on an extruder and have red phosphorus as a flame-proofing agent incorporated therein, which in turn con-tains an oxidation stabilizer, it i~ generally accepted that the oxidation stabilizer should present thermal stability in the absence of any tendency to split off water or to undergo decomposition, even at temperatures above 300 C.
This is a disadvantageous effect which has also been encountered in the stabilization process described in German Of~enlegungsschrift 2,6229296. In that process, the stabilizing effect is achieved by precipitating small amounts of metal salts of various acid orthophosphoric acid esters onto the sur~ace of the red phosphorus.
..
112~3292 The orthophosphoric acid metal salts suggested for use as stabilizers in German Offenlegungsschri~t 2 631 532, produce material which has an inadequate stability to oxidation for a variety of uses.
The metal salts of phosphonic acids and phosphinic acids (cf. German Offenlegungsschrift 2 ~47 093 and German Offenlegungsschrift 2 632 296 respectively) ad-mittedly produce good thermal stability and oxidation stability, but they are relatively expensive products and have to be used in proportions as high as 3 - 5 %
by weight.
As described in German Patent Specification 2 655 739 and German Offenlegungsschrift 2 705 042 it is possible for the stability to oxidation of red phosphorus to be effectively improved by applying a thin layer of a melamine/
formaldehyde resin to the surface of the red phosphorus particles. However, these stabilizers prove unsatisfactory inasmuch as the stabilizing effect is largely lost if the stabilized phospho~us is stored under tropical conditions, that is to say at ~0 C and 100 % relative atmospheric moisture, such as are simulated in the modified Indian Standard Test (I~ 2012 - 1961~.
Finally, German Patent Specification 2 625 674 dis-closes an agent which permits the use of red phosphorus in plastics, without hydrogen phosphide being liberated as a result of the processing temperature of the plast1c and of the presence of small amounts of water or moisture in the plastic to be processed. The agent comprises epoxide :` ~
IlZ~29Z
resins, which envelop the phosphorus particles, the resins being used in proportions of 5 - 50 Yo by weigh~
We have now unexpectedly found that the stabilization of red phosphorus can be improved by replacing the epo~ide resin by a mixture of an epoxide resin and aluminum hydroxide, of which a thin layer is applied to the sur~ace of the red phosphorus.
The present invention relates more particularly to sta-bilized, pulverulent red phosphorus, consisting of phosphorus particles having a particle size of at most about 2 mm, and an oxidation stabilizer envelopping the phosphorus particles in the form of a thin layer, the phosphorus containing a) as the oxidation stabilizer a combination of aluminum hydroxide and a hardened epoxide resin system having an epoxide equivalent weight of about 170 to 500, b) the oxidation stabilizer in a total proportion of 0.1 - 5 % by weight, based on the quantity of red phosphorus, and c) the aluminum hydroxide in the red phosphorus in a proportion of about 0.01 to ~ % by weight, and the epoxide resin in a proportion of about 0.09 to 4.99 %
by weight, in each case based on the quantity of red phosphorus.
A preferred embodiment of the invention pro~ides for the epoxide resin to be an e~oxide~phenolic resin, such as, for example, the reaction product of epichlorohydrin and 2,2-bis-(4~hydroxyphenyl)-propane (bisphenol A) or an epoxide resin ester.
~i ~ ` 112~329;~
The invention also relates to a process for the manufacture of stabilized pulverulent red phosphorus, which comprises introducing a water~soluble aluminum salt and an aqueous or alcoholic solution or dispersion o~ an epoxide resin and of a hardener into an aqueous suspension of the red phosphorus, establishing a pH-value within the range about 5 to 9, stirring the mixture for 1 to 3 hours at a temperature of 20 to 90 C, with pre-cipitation of the aluminum hydroxide and hardening of the epoxide resin, and filtering the s-tabilized phosphorus and finally drying it at an elevated temperature.
Further preferred features of the present invention provide for the resin component to comprise:
a) liquid epoxide resinswhich combine a very low to medium viscosity with a 100 % reactivity and are hardenable with water-soluble or water-emulsi-fiable hardeners, or b) unmodified, liquid 100 % reactive reaction products of epichlorohydrin and bisphenol A, which are hardenable with water-soluble or water-emulsifiable hardeners, or c) an aqueous epoxide-phenolic resin dispersion or water-emuisifiable 9 100 % reactive epoxide resin ester, either of which is hardenable with water-soluble or water-emulsifiable hardeners.
The epoxide resins are hardened in a conventional manner, for example in an queous phase at a temperature of 20 - 90 C and while maintaining a pH value o~ the ... . .. . .. . . .. . . . . . . . . .
~Z82~Z
aqueous phase of 5 - 9; suitable hardeners include water-soluble, internally modified pol~mines or water-emulsifiable polyaminoamides.
The red phosphorus stabilized in accordance with the invention, and the process for its manu~acture, com-pare favorably with the prior art inasmuch as the stabilizer is thermally stable and is furthermore so effective that even the addition of very small amounts results in red phosphorus of adequate stability for a wide variety of uses.
The invention is illustrated by the ~ollowing examples.
500 ml of an aqueous phosphorus suspension containing 250 g of pulverulent red phosphorus were diluted with 250 ml o~ water, brought to a p:~ value of 4 by adding 5 % strength H2S04, and warmed to 60 C. After dropwise addition o~ a solution of 5.3 g o~ A12(S04)3 18 H20 in 50 ml o~ water, and of an emulsion of 1.0 g of a liquid, very low-viscosity epoxide resin A ~ eckopox EP 128 from Hoechst Aktiengesellschaft, Frankfurt/Main) having an epoxide equivalent weight of about 200 and a density, at 25 C, of 1.12 g/ml, and 1.0 g of a water-soluble, internally modified aliphatic polyamine hardener ~ eckopox VEH 21~0 from Hoechst Aktiengesellschaft, Frankfurt~Main), having an H-equivalent w~ght of about 200 and a density, at 25 C, of 1.10 g/ml, in 50 ml of w.~ter, the suspension was brought to a pH-value o~ 5 by adding 5 % strength by weight sodium hydro~ide solution. Next 9 the suspension was stirred for 1 hour at 60 C, and then brought to a pH-value of 7 with 5 % strengt~
llZ8Z9~
by weight sodium hydroxide solution. A~ter stirring for a further 15 minutes, t~e mixture was ~lltered and the filter residue was washed wi-th wa-ter and dried in a s~rearn of nitrogen at 100 C. The proportion o~ aluminum hydroxide in the dried red phosphorus was 0.46 ~0 by weight and the proportion of epoxide resin was 0.68 % by ~eight, based on the amount of red phosphorus employed.
The oxidation stability of the red phosphorus stabilized as described above was tested in accordance with the two test procedures described ~elow.
Test 1:
450 ml o~ water and 1 g of the pretreated red phos-phorus were introduced into a three-necked flask equipped with a gas inlet tube, thermometer, reflux condenser and magnetic stirrer, the mixture was warmed to 80 C and 10 litres of oxygen per hour were passed into the mixture, under agitation. The gas mixture which escaped via the re-flux condenser and consisted of oxygen and hydrogen phosphide which had been produced, together with acids o~ phosphorus of various oxidation levels, by disproportionation o~ the red phosphorus, was led through two washbottles which were arranged one downstream o~ the other, and which each con-tained 100 ml of a 2.5 % strength by weight aqueous mercury (II)chloride solu~ion~
In this method, the phosphine reacted with the mercury~II) chloride in accordance with the followin~
equation:
PH3 + 3 HgCl2 ~ P(HgCl)3 ~ ~ HCl . .. . . . .. ..
The amount of oxo-acids of phosphorus contained in the aqueous suspension of the red phosphorus~ and ~he hydrochloric acid contained in the gas washbottlcs, scrtred as an index of the oxidation stability of the red phos-phorus. The contents of phosphorus acids and of hydrochloricacid were determined titrimetrically. The values calculated therefrom are shown in Table 1) columns A and B. Column A
sh~ws the amount of PH~ (mg o~ PH3 per gram of phosphorus per hour) formed during oxidation of the red phosphorus.
The values in column B are index o~ the acidity of the aqueous phosphorus-containing suspension, resulting from the formation of phosphorus acids during oxidation of the phosphorus(mg o~ KOH per gram of phosphorus per hour).
Test 2:
The oxidation stability was determined on the basis of Indian Standard "Specification of red phosphorus"
(IS 2012 - 1961).
For this purpose, 5.0 g of red phosphorus was weighed out into a crystallizing dish of 50 mm diameter and the dish was stored in a closed glass vessel for 168 hours at 5~ C
and 100 % relative atmospheric humidity. The phosphine thereby formed was expelled from the glass vessel by means of a stream of air (10 l/h) and caused to react with 2.5 %
strength by weight mercury(II) chloride solution in a gas washbottle, and the amount of hydrochloric acid thereby formed was determined titrimetrically.
To determine the content of the various o~o-acids of phosphorus, the sample of phosphorus was trans~erred into a 250 ml beaker, 120 ml of water and 40 ml of _ g _ ~12~ 3Z
n-propanol were added, and the mixture was heated to the boil for 10 minutes and then filtered. The quantitative analytical determination of the oxo-acids in the ~ rate was then carried out by titration with 0.1 N NaOH up to the equivalent point for the 2nd titration stage, at pH 9.5.
The values calculated therefrom are shown in Table 2.
The procedure followed was analogous to Example 1, but 10.6 g of aluminum sulfate were used. The proportion of aluminum hydroxide in the dried red phosphorus was 0.92 % by weight and the proportion of epoxide resin was 0.67 % by weight. The values of-the oxidation stability o~ the red phosphorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE_~
The procedure followed was analogous to Example 1, but 1.1 g o~ aluminum sulfate were used. The proportion of aluminum hydroxide in the dried red phosphorus was 0.10 % by weight and the proportion of epoxide resin was 0.72 % by weight. The values of the oxidation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
The procedure followed was analogous to Example 1, but 1.1 g o~ aluminum sul~a~e, 0.5 g o~ epoxide resin A and 0.5 g of hardener were used. The proportion o~
aluminum hydroxide in the dried red phosphorus was 0.11 %
~L2~2~Z
by weight and the proportion of epoxide resin was 0.37 ~o by weight. The values of the oxidation stability of the red phosphorus t~eated in this ~anner are shown in Tables 1 and 2.
The procedure was analogous to Example 1, but 1.0 g of a liquid, very low-viscosity epoxide resin B (--Beckopox VEP 22 from Hoechst Aktiengesellschaft, Frankfurt/Main) with an epoxide equivalent weight of about 195 and a density, at 25 C, of 1.11 g/ml, and 1 D O g of the hardener of Example 1 were used. The proportion of aluminum hydroxide in the dried red phosphorus was 0.46 % by weight and the proportion of epoxide resin was 0.67 ~ by weight.
The values of the 02idation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE_6 The procedure was analogous to Example 5, but 10.6 g of aluminum sulfate were used. The proportion of aluminum hydroxide in the dried red phosphorus was 0.94 % by weight and the proportion of epoxide resin was 0.68 % by weight.
The values of the oxidation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
The procedure was analogous to Example 5 t but 1.1 g of aluminum sulfate was used. The pro-portion of aluminum hydroxide in the dried red phosphorus was 0.11 % by weight and the proportion of ~oxide resin was 0.74 % by weight. The values of the oxidation stability 9z of the red phosphorus treated in this manner are shown in Tables 1 and 2.
. . _ The procedure was analogous to Example 5, but 1.1 g o~ aluminum sulfate, 0.5 g of epoxide resin B and 0.5 g of hardener were used. The proportion of aluminum hydroxde in the dried red phosphorus was 0.11 /0 by weight and the proportion of epoxide resin was 0.~6 % by weight. The values of the oxidation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE 9 (Comparative Example) The procedure was analogous to Example 1 but no aluminum sulfate was used. The proportion of epoxide resin in the dried red phosphours was 0.74 % by weight.
The values of the oxidation stability of the red phos-phorus treated in this manner are shown în Tables 1 and 2.
EXAMPLE 10 (Comparative Example) The procedure was analogous to Example 5, but no aluminum sulfate was used. The proportion of epoxide resin in the dried red phosphorus was 0~70 % by weight.
The values of the oxidation stability o~ the red phos-phorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE 11 (Comparative Example) The procedure was analogous to Example 1, but neither epoxide resin nor epoxide hardener was employed. The pro-portion o~ aluminum hydroxide in the dried red phosphorus was 0.48 % by weight. The values of the oxidation stability _ 12 -9~
o~ the red phosphorus treated in this manner are shown in Tables 1 and 2.
EXAMPLE 12 (Comparative Example) The procedure was analogous to Example 2, but neither epoxide resin nor epoxide hardener was employed. The pro-portion of aluminum hydroxide in the dried red phosphorus was 0.92 % by weight. The values of the oxidation stability of the red phosphorus treated in this manner are shown in Tables 1 and 2.
It follows from the data in Tables 1 and 2 that the aluminum hydroxide/epoxide resin stabilizer according to the invention is capable of achieving an improved stabilizing effect, with a smaller total amo~nt of stabilizer, than with -the use of aluminum hydroxide or epoxide resin alone.
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Claims (10)
WE CLAIM:
1) An improved stabilized pulverulent red phosphorus consisting of phosphorus particles having a particle size of at most about 2 mm, and an oxidation stabilizer enveloping the phosphorus particles in the form of a thin layer, the improved phosphorus containing a) as the oxidation stabilizer a combination of aluminum hydroxide and a hardened epoxide resin system having an epoxide equivalent weight of about 170 to 500 9 b) the oxidation stabilizer in a total proportion of 0.1 - 5 % by weight, based on the amount of red phosphorus, and c) the aluminum hydroxide in a proportion of about 0.01 to 3 % by weight, and the epoxide resin in a proportion of about 0.09 to 4.99 % by weight, based in each case on red phosphorus.
2) Red phosphorus as claimed in claim 1, wherein the epoxide resin is an epoxide-phenolic resin.
3) Red phosphorus as claimed in claim 1, wherein the epoxide resin is a reaction product of epichlorohydrin and 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A).
4) Red phosphorus as claimed in claim 1, wherein the epoxide resin is an epoxide resin ester.
5) In the process for the manufacture of the stabilized pulverulent red phosphorus, consisting of phosphorus particles having a particle size of at most about 2 mm, and an oxidation stabilizer which envelops the phosphorus particles in the form of a thin layer, the improvement which comprises introducing a water soluble aluminum salt and an aqueous or alcoholic solution or dispersion of an epoxide resin and of a hardener into an aqueous suspension of the red phos-phorus, establishing a pH-value of about 5 to 9, stirring the mixture for 1 to 3 hours at a temperature of 20 to 90° C, with precipitation of the aluminum hydroxide and simultaneous hardening of the epoxide resin, filtering off the stabilized phosphorus and finally drying it at an elevated temperature.
6) The process as claimed in claim 5, wherein the epoxide resin is a liquid epoxide resin which has a very low to medium viscosity, is 100 % reactive and is hardenable with water-soluble or water-emulsifiable hardeners.
7) The process as claimed in claim 5, wherein the epoxide resin is an unmodified, liquid 100 % reac-tive reaction product of epichlorohydrin and bisphenol A, which is hardenable with water-soluble or water-emulsifiable hardeners.
8) The process as claimed in claim 5, wherein the epoxide resin employed is an aqueous epoxide-phenolic resin dispersion or water-emulsifiable 100 % reactive epoxide resin ester, either of which is hardenable with water-soluble or water-emulsifiable hardeners.
9) The process as claimed in claim 5, wherein the hardener employed is a water-soluble, internally modified polyamine or water-emulsifiable poly-aminoamide.
10) The process as claimed in claim 5, wherein the epoxide resins are hardened in aqueous phase at a temperature of 20 - 90° C and in a pH range of 5 - 9.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2945118A DE2945118C2 (en) | 1979-11-08 | 1979-11-08 | Stabilized red phosphorus and process for its manufacture |
| DEP2945118.1 | 1979-11-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1128292A true CA1128292A (en) | 1982-07-27 |
Family
ID=6085488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA364,042A Expired CA1128292A (en) | 1979-11-08 | 1980-11-05 | Stabilized red phosphorus and process for its manufacture |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4315897A (en) |
| EP (1) | EP0028744B1 (en) |
| JP (1) | JPS5673606A (en) |
| CA (1) | CA1128292A (en) |
| DD (1) | DD154212A5 (en) |
| DE (2) | DE2945118C2 (en) |
| IN (1) | IN153496B (en) |
| SU (1) | SU1068023A3 (en) |
Families Citing this family (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1214314A (en) * | 1983-12-08 | 1986-11-25 | Helena Twardowska | Stabilization of red phosphorus |
| US4489183A (en) * | 1983-12-13 | 1984-12-18 | Erco Industries Limited | Stabilization of red phosphorus |
| DE3436159A1 (en) * | 1984-10-03 | 1986-04-10 | Hoechst Ag, 6230 Frankfurt | STABILIZED AND PHLEGMATIZED GIANT RED PHOSPHOR |
| IT1200424B (en) * | 1985-03-19 | 1989-01-18 | Saffa Spa | RED PHOSPHORUS STABILIZED FOR USE AS A FLAME RETARDANT, ESPECIALLY FOR POLYMER-BASED COMPOSITIONS |
| JPS6221704A (en) * | 1985-07-17 | 1987-01-30 | Rin Kagaku Kogyo Kk | Coated red phosphorus, production and composition thereof, an production of high-voltage electronic part |
| US4879067A (en) * | 1986-06-19 | 1989-11-07 | Rinkagaku Kogyo Co., Ltd. | Red phosphorus flame retardant and nonflammable resinous composition containing the same |
| DE3710170A1 (en) * | 1987-03-27 | 1988-10-13 | Hoechst Ag | STABILIZED RED PHOSPHORUS AND METHOD FOR THE PRODUCTION THEREOF |
| CA1309789C (en) * | 1987-06-26 | 1992-11-03 | Ichiro Sakon | Method for producing red phosphorus flame retardant and nonflammable resinous composition |
| DE4039906A1 (en) * | 1990-12-14 | 1992-06-17 | Hoechst Ag | Stabilised, powdered red phosphorus@ - coated with uncured epoxy! resin as oxidn. stabiliser |
| DE4039905A1 (en) * | 1990-12-14 | 1992-06-17 | Hoechst Ag | Stabilised, powdered red phosphorus@ - coated with tin oxide hydrate and uncured epoxy] resin as oxidn. stabilisers |
| JP2832672B2 (en) * | 1993-08-12 | 1998-12-09 | 燐化学工業株式会社 | Red phosphorus flame retardant and flame retardant resin composition |
| DE10058922A1 (en) | 2000-11-28 | 2002-06-06 | Clariant Gmbh | Stabilized red phosphorus and a process for its manufacture |
| US20060219341A1 (en) | 2005-03-30 | 2006-10-05 | Johnston Harold E | Heavy metal free, environmentally green percussion primer and ordnance and systems incorporating same |
| US7857921B2 (en) * | 2006-03-02 | 2010-12-28 | Alliant Techsystems Inc. | Nontoxic, noncorrosive phosphorus-based primer compositions |
| US8641842B2 (en) | 2011-08-31 | 2014-02-04 | Alliant Techsystems Inc. | Propellant compositions including stabilized red phosphorus, a method of forming same, and an ordnance element including the same |
| US8540828B2 (en) | 2008-08-19 | 2013-09-24 | Alliant Techsystems Inc. | Nontoxic, noncorrosive phosphorus-based primer compositions and an ordnance element including the same |
| CA2942312C (en) | 2007-02-09 | 2019-05-28 | Vista Outdoor Operations Llc | Non-toxic percussion primers and methods of preparing the same |
| US8192568B2 (en) | 2007-02-09 | 2012-06-05 | Alliant Techsystems Inc. | Non-toxic percussion primers and methods of preparing the same |
| JP4818339B2 (en) * | 2007-10-29 | 2011-11-16 | ソニーケミカル＆インフォメーションデバイス株式会社 | Magnetic sheet |
| US8206522B2 (en) | 2010-03-31 | 2012-06-26 | Alliant Techsystems Inc. | Non-toxic, heavy-metal free sensitized explosive percussion primers and methods of preparing the same |
| CN111747387B (en) * | 2019-03-29 | 2022-06-17 | 扬州三涧科贸有限公司 | Yellow phosphorus mineral powder pelletizing binder, mineral powder pellets and preparation method thereof |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2359243A (en) * | 1943-08-13 | 1944-09-26 | Oldbury Electro Chemical Co | Treatment of phosphorus |
| US2635953A (en) * | 1947-10-08 | 1953-04-21 | Martin S Silverstein | Inflammable compositions including red phosphorus |
| DE1567629B1 (en) * | 1966-06-24 | 1970-05-27 | Knapsack Ag | Process for impregnating red phosphorus |
| DE2000033B2 (en) * | 1970-01-02 | 1971-11-11 | Knapsack AG, 5033 Hürth-Knapsack | PROCESS FOR MANUFACTURING PASSIVATED RED PHOSPHORUS |
| GB1458194A (en) * | 1973-06-25 | 1976-12-08 | Efence Secretary Of State For | Stabilisation of red phosphorus |
| CA1023694A (en) * | 1973-11-19 | 1978-01-03 | Texas Gas Transmission Corporation | Multi-step chemical and radiation process for the production of gas |
| FR2314221A1 (en) * | 1975-06-10 | 1977-01-07 | Rhone Poulenc Ind | COMPOSITIONS INTENDED FOR THE FLAME PROTECTION OF PLASTICS |
| JPS52125489A (en) * | 1976-04-08 | 1977-10-21 | Phosphorus Chem Ind | Method of reforming red phosphorus |
| DE2622296C2 (en) * | 1976-05-19 | 1984-12-06 | Hoechst Ag, 6230 Frankfurt | Stabilized red phosphorus and process for its manufacture |
| DE2631532C2 (en) | 1976-07-14 | 1984-09-13 | Hoechst Ag, 6230 Frankfurt | Stabilized powdered red phosphorus and process for its manufacture |
| DE2632296C2 (en) * | 1976-07-17 | 1979-02-01 | Hoechst Ag, 6000 Frankfurt | Stabilized red phosphorus and process for its manufacture |
| GB1576879A (en) * | 1976-09-20 | 1980-10-15 | Hitachi Ltd | Flame-retardant epoxy resin compositions |
| DE2647093C2 (en) | 1976-10-19 | 1984-12-06 | Hoechst Ag, 6230 Frankfurt | Stabilized powdered red phosphorus and process for its manufacture |
| DE2655739C2 (en) * | 1976-12-09 | 1978-12-14 | Hoechst Ag, 6000 Frankfurt | Stabilized red phosphorus and process for its manufacture |
| DE2705042A1 (en) * | 1977-02-08 | 1978-08-10 | Hoechst Ag | STABILIZED RED PHOSPHORUS AND THE METHOD OF MANUFACTURING IT |
| DE2813151A1 (en) * | 1978-03-25 | 1979-09-27 | Hoechst Ag | STABILIZED RED PHOSPHORUS |
-
1979
- 1979-11-08 DE DE2945118A patent/DE2945118C2/en not_active Expired
-
1980
- 1980-10-24 EP EP80106517A patent/EP0028744B1/en not_active Expired
- 1980-10-24 DE DE8080106517T patent/DE3062370D1/en not_active Expired
- 1980-11-03 IN IN1243/CAL/80A patent/IN153496B/en unknown
- 1980-11-05 CA CA364,042A patent/CA1128292A/en not_active Expired
- 1980-11-06 SU SU803003448A patent/SU1068023A3/en active
- 1980-11-06 JP JP15528080A patent/JPS5673606A/en active Pending
- 1980-11-10 DD DD80225088A patent/DD154212A5/en not_active IP Right Cessation
- 1980-11-10 US US06/205,627 patent/US4315897A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0028744B1 (en) | 1983-03-16 |
| DE2945118C2 (en) | 1981-12-03 |
| SU1068023A3 (en) | 1984-01-15 |
| JPS5673606A (en) | 1981-06-18 |
| DE3062370D1 (en) | 1983-04-21 |
| DE2945118B1 (en) | 1981-04-02 |
| EP0028744A1 (en) | 1981-05-20 |
| IN153496B (en) | 1984-07-21 |
| US4315897A (en) | 1982-02-16 |
| DD154212A5 (en) | 1982-03-03 |
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