DE2408488A1 - GRANULATES MADE FROM RED PHOSPHORUS AND A BINDING AGENT FOR FLAME RETARDANT FINISHING OF PLASTICS - Google Patents

Description

KNAPSACK AKTIENGESELLSCHAFT

K 1096 II

Granules made from red phosphorus and a binder for making plastics flame-retardant

It is known to use red phosphorus to make plastics flame-retardant, with the powdery red Phosphorus is generally incorporated in a manner adapted to the respective plastic and the phosphorus-containing plastic then granulated. is.

In German Offenlegungsschrift (DOS) 1 931 387, for example, a self-extinguishing, glass fiber reinforced molding compound based on polyamides which contains 0.5 to 15% red phosphorus as a flame retardant is described. The preparation of these molding material takes place in that the glass fiber reinforced polyamide-6 pellets with different amounts of red phosphorus by tumbling in a rolling vessel mixed, the mixture in an extruder at a temperature of 270-280 ⁰ C plasticized and pressed into strands and cooled Strands are chopped into cylindrical granules.

In a manner similar to that described in DOS 1 931 387, according to DOS 1 694 530 a non-smoldering phosphorus-containing Polyvinyl chloride can be obtained by preparing powdery polyvinyl chloride by suspension polymerization mixed with powdered red phosphorus and the mixture extruded and pressed to form an object is further processed.

ORIGINAL INSPECTED

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The aforementioned processes have the disadvantage that when processing powdery red phosphorus, dust is generated the health of the operating personnel is at risk and there is also a risk of the red Phosphorus is given. This disadvantage is also encountered in the manufacturing process explained in DOS 2,126,923 not avoided by flame retardant polyesters. This procedure involves the addition of powdered red phosphorus in the polyester approach during polyester production, for example the red phosphorus in ethylene glycol slurried in the presence of nitrogen as protective gas and the slurry with dimethyl terephthalate is polycondensed.

Furthermore, the German Auslegeschrift 1 965 635 discloses a process for the production of thermoplastic materials made flame-retardant with red phosphorus, which consists in treating red phosphorus impregnated with a lactam having 4 to 12 carbon atoms in incorporated the thermoplastic before, during or after the melting of the plastic, with the Lactam impregnated red phosphorus from a mixture of 25 to 90 percent by weight of finely divided red phosphorus and 10 to 75 percent by weight of lactam and optionally the lactam during or after incorporation into the thermoplastic plastic is largely or partially removed again by distillation.

The above known procedure assumes that the devices intended for processing the plastic are equipped with degassing devices for removing or recovering the lactam, with expulsion of the lactam from the plastic compound itself causes technical difficulties.

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It was therefore the task of using red phosphorus as a flame retardant in plastics before this To bring processing with the plastic into a completely dust-free, manageable state, so that the already mentioned Disadvantages of the known forms of application of red phosphorus can be avoided.

There is a solution to the problem posed according to the invention using a granulate consisting essentially of red phosphorus and a suitable binder, wherein the binding agent during processing of the granulate with the plastic, regardless of the type of plastic, does not have to be removed from the latter.

The invention thus relates to a homogeneous granulate for the flame-retardant finishing of plastics, containing powdery, red phosphorus with an upper grain size of up to about 100 μ and binders and is characterized in that the granules out

Melting point 180 ⁰ C - 10-97 weight ^ red phosphorus, 3-50% by weight of a at about 30

Binder, consisting of waxes and / or wax-like substances and / or Metal soaps and -

0-87% by weight of additives that improve the flame retardancy favor the granulate or, when the granulate is incorporated into plastics, the formation of gaseous phosphines prevent or are suitable as fillers,

consists.

According to a preferred embodiment of the invention, the granules contain 30-92% by weight of red phosphorus and 8-15 gel

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2608488

Klobuk% of one at 50 ° - 150 ⁰ C melting binder. The binder can, for example, be an ester wax with 12-32 carbon atoms, an amide wax with 12-22 carbon atoms, a hydrocarbon wax with 30-800, in particular 150-300 carbon atoms or a fatty acid, a fatty alcohol or a fatty acid ester with 12 to 22 carbon atoms or a metal soap.

Naturally occurring waxes, such as carnauba wax, candelilla wax or raw montan wax, and esterification products are suitable as ester waxes long chain natural or synthetic Carboxylic acids with mono- or polyhydric alcohols, for example stearyl alcohol, ethanediol, butanediol or glycerine. In particular esterification products of a wax acid mixture with ethylene glycol obtained by chromic acid oxidation of raw montan wax have been found or butylene glycol, with the ethylene glycol ester having, for example, a dropping point of 79 * can have the saponification number 142.

for example a dropping point of 79 ° C, the acid number 18 and

Suitable amide waxes are, for example, mono- or diamides, more natural or synthetic fatty acids, for example stearic acid amide, Oleic acid amide or bis-stearoyl-ethylenediamine.

Examples of hydrocarbon waxes are petroleum paraffins, microcrystalline waxes, synthetic paraffins and polyethylene waxes in question. A preferred hydrocarbon wax is polyethylene wax with a molecular weight of about 2000, a dropping point of 107 ° C and a density of 0.92.

Suitable fatty acids or their derivatives are, for example, natural or synthetic saturated or unsaturated fatty acids, Fatty alcohols or esters of fatty acids with monohydric or polyhydric alcohols. Glycerol fatty acid partial esters have proven particularly useful.

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Finally, the granulate can contain a metal soap, for example calcium stearate or calcium montanate, as a binding agent.

With the substances referred to as additives to the granulate, the properties of the granulate can be modified to a certain extent Directions to be improved. For example, the flame retardant effect of the granulate can be achieved by adding dibromoneopentyl glycol or of certain organic nitrogen compounds, which carbonize during combustion, be favored. Such nitrogen compounds are, for example, melamine or polyacrylonitrile.

It is known that the processing of plastics equipped with red phosphorus in the. Heat in extruders is linked to the formation of small amounts of gaseous phosphines. To prevent this effect, according to proposed according to the invention, a certain proportion of metal oxides, such as MgO, AlpO, GuO or PbO or of sulfamic acid or ammonium hydrogen sulfate.

In the case of the use of fillers in the granulate according to the invention, chalk, kaolin and talc have been found, for example or quartz flour as beneficial.

Another object of the invention is the production of the granules, the method being characterized in that the granulate components are intimately mixed and homogenized in an inert gas atmosphere of, for example, nitrogen or COp, then the mass obtained is granulated in a granulate molding machine using pressure and temperature, and the resulting mass Granulate cools down.

In particular, the following should be noted for the production of the granulate according to the invention:

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The distribution of the binders and possibly other additives in the red phosphorus is advantageously used in the plastics industry usual high-speed mixer. Slow-running mixers can also be used for this, if this is guaranteed is that after the end of the mixing process "there is a homogeneous mass.

If the binding agent is a wax with a higher melting point, it has proven to be useful to mix the granulate components carry out at elevated temperature, whereby the homogenization of the mixture is accelerated.

Granulating red phosphorus according to the invention with a relatively low proportion of the binder is advantageous made with such machines in which the powdery mixture is compressed under high pressure and is compacted. Under the influence of pressure and frictional heat, the binders soften or melt and re-emerge Solidification of the binding agent abrasion-resistant particles that can be easily distributed in a plastic melt. Using For higher-melting or hard binders, it is advantageous to warm up the mixture and / or the compacting machine.

For the production of abrasion-resistant granulate particles, gear granulate molding machines are particularly suitable, in which the Gears are in engagement and have bores at the tooth base or compacting machines, which consist of two counter-rotating ¥ Alzen exist that are either smooth or with indentations.

The inventive use of red phosphorus as granules for making plastics flame-retardant can be described as technically advanced, because it makes it

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on the one hand the handling of the red phosphorus becomes easy and safe and on the other hand the removal of the binding agent can be dispensed with after the granulate has been incorporated into a plastic for the purpose of flair protection. Finally, it was found that the binders proposed according to the invention have the properties of the plastic do not adversely affect them and are therefore plastic-friendly. For example, the granules can after of the invention polycaprolactam, polyethylene, polypropylene, polystyrene or a polyolefin terephthalate as a flame retardant component are added, the granules in the plastic preferably in an amount of 5 to 40% by weight "■ is introduced.

The subject matter of the invention is explained in more detail in the following examples, the production of the granules was carried out by means of a gear granulating molding machine. the Bores in the tooth base of the machine mentioned had a circular diameter of 2 mm and 4 mm and the granulating head the machine was under a carbon dioxide atmosphere.

Example 1 ■

90.0 parts by weight of red phosphorus, 2 parts by weight of copper (II) oxide and 8.0 parts by weight of a powdery ester wax with a dropping point of 79 ° C., an acid number of 18 and the saponification number 142, were mixed intensively in a high-speed mixer under a nitrogen atmosphere, the temperature being the Mixture rose to 75 ° C by friction. The ester wax was obtained by esterifying a by chromic acid oxidation of Montan wax obtained wax acid mixture with ethylene glycol manufactured.

The warm mixture obtained in the high-speed mixer was then in the granulating molding machine, its gears

509835/0977 " ⁸

were tempered to about 70 ⁰ C, processed into a cylindrical, abrasion-resistant granulate 2 mm in diameter and 6 mm in length.

Example 2

44.0 parts by weight of red phosphorus, 42.0 parts by weight of melamine, 2.0 parts by weight of sulfamic acid and 12.0 parts by weight of a powdered polyethylene wax with a molecular weight of about 2000, a dropping point of 107 ° C. and a density of 0.92 were in a high-speed mixer under nitrogen atmosphere intensively mixed, wherein the temperature of the mixture rose to about 100 ⁰ C. The warm mixture was then processed into cylindrical, abrasion-resistant granules with a diameter of 2 mm and a length of about 6 mm by pressing in the granulating molding machine, the gears of which ^{were tempered to about 70 ° C.}

Example 3

45.0 parts by weight of red phosphorus, 43.0 parts by weight of dibromoneopentyl glycol, 2 parts by weight of ammonium hydrogen sulfate and 10.0 parts by weight of a glycerol fatty acid partial ester present as a powder with a dropping point of 58 ° C, the acid number 3 and the saponification number 180 were in one high-speed mixer intensively mixed under a nitrogen atmosphere, keeping the temperature of the mixture to a maximum of 3O ⁰ C increase.

The mixture was then closed by pressing in the granulating / molding machine, the gears of which were not tempered a cylindrical, abrasion-resistant granulate with a diameter of 2 mm and a length of about 6 mm.

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Example 4

The flame retardant effect of Example 1 was herge-. put granules tested in polycaprolactam. To this The purpose was 93 parts by weight of polycaprolactam granules and 7 parts by weight of flame retardant granules in a tumble mixer intimately mixed under a carbon dioxide atmosphere and then Plasticized in a twin-screw extruder at 270-280 ° C. and extruded as a strand. For cooling the strand passed through a water bath. The strand was then granulated and the granulate was dried at 110.degree.

The granulate was pressed into 6.4 mm thick plates and into sample sizes according to the regulations for Burn tests sawed up. The burn-off tests were carried out according to the regulations of the "Underwriters' Laboratories" (UL 94) or according to DIN regulation 53438 carried out. According to UL 94 this corresponds Granules of the classification SE 0 (SE = self-extinguishing). According to DIN 53438, the granulate is to be classified in class K 1 with a sample thickness of 6.4 mm.

Example 5

a) 90 parts by weight of low-pressure polyethylene granules with a melt index i, - (according to DIN 53 735) of about 20 and 10 Parts by weight of the granules for anti-felling agent according to Example 2 were mixed in a tumble mixer after premixing extruded and granulated as a strand in a twin screw extruder.

plasticized in a twin screw extruder at around 190 C,

Those produced from the granulate by pressing at 170 ° C Panels 6.4 mm thick gave the following charring results:

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Classification according to UL 94: SE 0

"" DIN 53 438: Κ1 / β, 4 mm

b) Instead of the flame retardant granules according to Example 2, 90 parts by weight of low-pressure polyethylene 10 parts by weight of flame retardant granules according to Example 3 were used. The following result was obtained in the burn test obtain:

Classification according to UL 94: SE 0

"" DIN 53 438: K1 / 6.4 mm

Example 6

85 parts by weight impact-resistant polystyrene granules with a "melt index i, - (according to DIN 53 735) were mixed with 15 parts by weight Flainmschutzmittelgranulat according to Example 3 in a tumble mixer under a carbon dioxide atmosphere, plasticized in a twin-screw extruder at 180 ⁰ C, extruded and granulated by about 4 hours. The press plates of 6.4 mm thickness made from the plastic granulate at 170 ° C. gave the following charring values:

Classification according to UL 94: SE 0

"" DIN 53 438: Ki / 6.4 mm

The extrusion of the respective granulate mixtures according to Examples 1-6 showed only an insignificant increase Power consumption of the extruder compared to that during the extrusion of pure plastic granulates.

The phosphine concentration measured in the vicinity of the exit of the plastic strand from the extruder fell below the level

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in all cases the permissible MAK limit of 0.1 ppm, whereby the MAK is the maximum working concentration or the maximum means permissible phosphine concentration at the workplace.

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Claims (5)

- 12 patent claims: 1. Homogeneous granulate for the flame-retardant finishing of plastics, containing powdery, red ones. Phosphorus of an upper grain size, up to about 100 and binders, characterized in that the granules consist of 10-97 weight ^ red phosphorus, 3-50 weight ^ of about 30 ° - melting 180 ⁰ C. Binder, consisting of Viaxxes and / or wax-like substances and / or Metal soaps and 0-87 weight ^ of additives, which the flame retardant effect favor the granulate or when incorporating the granulate into plastics prevent the formation of gaseous phosphines or are suitable as fillers, consists. 2. Granules according to claim 1, characterized in that it 30-92 weight ^ red phosphorus and 8-15 weight ^ one Contains binder. 3 · granulate according to claim 1 or 2 _y characterized in that the binder at 50 ° - 150 ⁰ C melts. 4. Granules according to claims 1-3, characterized in that the binder is an ester wax with 12-32 carbon atoms, an amide wax with 12-22 carbon atoms, a hydrocarbon wax with 30-800, in particular 150-300 carbon atoms or a fatty acid, a fatty alcohol or a fatty acid ester with 12 to 22 carbon atoms or a metal soap. - 13 - 509835/0977 2408A88 5. Granules according to claim 4, characterized in that the ester wax is carnauba wax, candelilla wax, raw montan wax, the esterification product of a long-chain, natural or synthetic carboxylic acid with a monohydric or polyhydric alcohol or a wax acid mixture obtained by chromic acid oxidation of raw montan wax with ethylene glycol or butylene glycol. 6. Granules according to claim 5, characterized in that the Esterification product from the wax acid mixture with ethylene glycol has a dropping point of '
Has saponification number 142. glycol has a dropping point of 79 ° C, the acid number 18 and the 7. Granules according to claim 4, characterized in that it as amide wax contains mono- or diamides of natural or synthetic fatty acids. 8. Granules according to claim 4, characterized in that the amide wax is stearic acid amide, oleic acid amide or bis-stearoylethylenediamine. 9. Granules according to claim 4, characterized in that the hydrocarbon wax is a petroleum paraffin or synthetic paraffin, a microcrystalline wax or a polyethylene wax. 10. Granules according to claim 9, characterized in that the polyethylene wax has a molecular weight of about 2000, a dropping point of 107 ° C and a density of 0.92. 11. Granules according to claim 4, characterized in that they contain natural or synthetic, saturated or unsaturated fatty acids, fatty alcohols or fatty acid esters with mono- or polyhydric alcohols. - 14 509835/0977 12. Granules according to claim 4, characterized in that the fatty acid ester is a glycerol-fatty acid partial ester which has a dropping point ■
number 180 owns. a dropping point of 58 ⁰ C, the acid number 3 and the saponification 13. Granules according to claim 4, characterized in that it contains calcium stearate or calcium montanate as metal soap. 14. Granulate according to claim 1-13, characterized in that it contains additives melamine, polyacrylonitrile, amidosulfonic acid, ammonium hydrogen sulfate, cupric oxide, AlpO ,, PbO, MgO, dibromoneopentylglyko1 or a mixture of these substances. 15. A method for producing the granulate according to claim 1-14, characterized in that the granulate components are intimately mixed and homogenized in an inert gas atmosphere, then the mass obtained is granulated in a granulate molding machine using pressure and temperature and the resulting granulate is cooled. 16. The method according to claim 15, characterized in that the inert gas is nitrogen or carbon dioxide. 17. The method according to claim 15 or 16, characterized in that the mixing of the granulate components is carried out at a temperature which corresponds to the softening point of the binder. 18. Use of the granules according to claims 1-14 as a flame retardant additive for polycaprolactam, polyethylene, polypropylene, polystyrene or polyolefin terephthalate. 19. Use according to claim 18, characterized in that the granules are contained in the plastic in an amount of about 5 Ms 40 weight ^. 5 0 9 8 3 5 / j £ ..
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