CH666045A5 - FLAME RETARDANT COMBINATION. - Google Patents

Description

DESCRIPTION

The invention relates to flame retardant mixtures which are incorporated in the form of microcapsules in polymeric organic material. It has been found that microcapsules which contain a mixture of at least one flame-retardant, halogenated organic compound (component a) and an inorganic oxide, hydroxide, borate or phosphate (component b) are outstandingly suitable as flame retardants for polymeric organic substances.

Halogenated, flame-retardant organic compounds are to be understood above all as the compounds known as such and containing chlorine and / or bromine, the molecular weight of which can be attributed to 20 to 75 percent, preferably 40 to 75 percent, to the content of halogen atoms; the number of carbon atoms to halogen atoms here is approximately 5: 1 to 1: 1. The preferred compounds melt between about 50 and 350 ° C, so they are solid at ambient temperature.

For example, particular preference is given to Tetrabromophthalic acid anhydride or imide; halogenated carboxylic acid esters, e.g. 2,2-bis (bromomethyl) -3-bromopropyl carbonate; Tribromophenyl carbonate; Halogen terephthalic acid esters, e.g. Bis (2,3-dibromopropyl) terephthalate; halogenated diphenyl oxide, e.g. De-cabromodiphenyl ether; halogenated benzene, toluene, xylene or ethylbenzene, e.g. B. hexabromobenzene, pentabromotoluene, tetrabromoxylene and pentabromethylbenzene; halogenated cyclic (saturated or unsaturated) compounds, e.g. B. hexabromocyclodecane, dibromomethyl-dibromocyclohexane, hexabromomethylbenzene, perchloropentacyclodecane; halogenated bisphenols, optionally dialkoxylated, e.g. halogenated alkyl aryl ethers, in particular 2,2-bis- [4- (2, '3'-dibromopropoxy) -3,5-dibromophenyl] propane; Bicyclo [2,2,1] heptane-2,3-dicarboxylic acid derivatives, e.g. the compound of formula

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brominated polymers, e.g. Poly (tribromostyrene), and brominated polyphenyl ether and chlorinated paraffin with a chlorine content between 20 and 75 percent by weight. Among these compounds are the chlorinated paraffins and the brominated cycloaliphatic compounds, e.g. B. Hexabromocyclo-

dodecane, as well as the brominated diphenyls and diphenyl ethers, in particular those of the formula in which n = 0 or 1 and x and y are 2 to 5, the sum x + y being 4 to 10, are preferred.

Component b is preferably an oxide, hydroxide,

Borate and / or a phosphate of Mg, Al, Si, Sn, Sb, Bi, Ti, Fe, Zn, Mo or tungsten, in particular magnesium or aluminum hydroxide, antimony or bismuth oxide or zinc borate, especially Sb203, SbîOs or Zinc borate, especially Sb203.

The weight ratio of components a: b is generally between 5: 1 and 1: 2, preferably between 4: 1 and 1: 1, in particular between 3: 1 and 3: 2.

In general, the diameter of the microcapsules is up to 100 μm, preferably up to 75 μm, in particular up to 50 μm. The weight ratio of wrapping material to capsule content (tare to net) is generally 1: 1 to 1: 150, preferably 1: 5 to 1: 100, in particular 1:25 to 1:75 (“fili” about 50 to 99.3 percent, preferably 80 to 99 percent, in particular 96 to 98.6 percent).

Among the materials which can be given a flame-resistant finish according to the invention, all organic polymers should be mentioned in general, in particular polyolefins (e.g. polyethylene, polypropylene and their copolymers), linear saturated polyesters (e.g. polyethylene terephthalate, polybutylene terephthalate etc.), unsaturated polyesters (e.g. on Maleic acid base), polyamides (e.g. all types of nylon), polyacrylates and methacrylates (e.g. PMMA), polystyrene, ABS polymers, polyurethanes, polyacrylonitrile and its copolymers, cellulose esters, epoxy resins and polyvinyl chloride.

The microcapsules are incorporated into polymer compositions by generally known methods. So you can z. B. the monomers or prepolymers are added before the polymerization or the finished polymers in the extruder.

The microcapsules can also be processed into a masterbatch (concentrate) and added as such to the polymers. Corresponding concentrates generally contain 20 to 90, preferably 40 to 80 percent by weight of microcapsule material, the rest is a (compatible) polymer which is readily dispersible in the intended substrate. The concentrate can also be a suspension of the microcapsules (preferably containing 20 to 90, in particular 40 to 80 percent by weight capsules) in an organic solvent.

The capsule material (the covering) is preferably a polymer which is insoluble in the substrate (the flame-retardant polymer composition), so that it is ensured that the flame-retardant compound mixture is retained in the form originally used (microcapsules) until the substrate is heated to a temperature which is close to the flash point of the substrate (about 200 ° C).

The capsule material (the enveloping membrane) consists e.g. made from gum arabic, gelatin, cellulose acetate phthalate or phenol formaldehyde resin.

The flame retardant compounds, components a and b, are processed into microcapsules by generally known methods.

The microencapsulation offers several significant advantages over the use of flame retardants without further measures: There is no corrosion of the substrate processing machines by the flame retardant compounds; the light stability of the treated substrates is not affected by the flame retardants; flame retardant at the processing temperature of the substrates

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mer do not vaporize / sublimate; easily migrating flame retardant compounds cannot "bloom" on the substrate surface. Another very important fact is that flame retardants contained in microcapsules have a noticeably better effect than homogeneously distributed flame retardants.

It can be assumed that the encapsulated flame retardants work as follows: When a temperature close to the flash point (approx. 200 ° C) is reached, the capsules break open, the inorganic compounds react with the halogenated organic compounds, the reaction products penetrate the substrate and develop the flame retardant effect .

In general, the microcapsules can be produced by known methods or in analogy to Examples 1 to 3.

In the following examples, parts are parts by weight and percentages are percentages by weight. The temperatures are given in degrees Celsius.

example 1

Production of microcapsules with a gelatin / gum arabic membrane

A 10% aqueous gelatin solution and a 10% aqueous gum arabic solution are prepared, 50 parts of the two solutions are mixed, 400 parts of water at 45 °, 66.7 parts of chlorinated paraffin (70% chlorine content, CP 70 from Hoechst) are added with stirring ) and 33.3 parts of SbzOs to the solution and stirred until a homogeneous suspension is obtained. Then 10 N acetic acid are added until pH 4 is reached. In the process, gelatin / gum arabic membranes form, which envelop particles of paraffin and SbzOa. The mixture is first cooled slowly to 25 °, then very quickly to 10 °, the membranes solidifying. To harden the membranes, 40 parts of a 25 percent aqueous glutaraldehyde solution are added, the mixture is stirred for a further 8 hours, after which the capsules are filtered off, washed and dried.

Example 2

Manufacture of microcapsules with a gelatin membrane

100 parts of a 10% aqueous gelatin solution are warmed to 45 ° with stirring, mixed with 250 parts (45 ° warm) of water and 20 parts of sodium hexametaphosphate (5 percent) / water mixture. Then, while stirring, 66.7 parts of chlorinated paraffin (as indicated in Example 1) and 33.3 parts of Sb2Û3 are added; when the mixture is homogeneous, the pH is adjusted to 4 with 10N acetic acid, the gelatin forming a membrane around the chloroparafin and SbîOî particles and forming microcapsules. The further treatment of the capsules is carried out as indicated in Example 1.

666045

The sodium hexametaphosphate is supplied by Gross Giuglio SPA, Monza, Italy.

Example 3

Manufacture of microcapsules with a cellulose acetate phthalate membrane

40 parts of a five percent aqueous cellulose acetate phthalate solution are mixed with 150 parts of water, 2 parts of urea, 66.7 parts of chlorinated paraffin (as in Example 1) and 33.3 parts of SbîOs, stirred until a homogeneous suspension is obtained, then Glauber's salt is added to coacervate the celulose acetate phthalate, and finally citric acid is added until pH 4 is reached. The capsule shells are stirred until the capsules have completely hardened, the capsules are filtered off, washed and dried. Instead of the chlorinated paraffin, the same amount of octa- or deca-bromo-diphenyl oxide or 1,2-bis (pentabromophenyloxy) ethylene can also be used.

Example 4

10 parts of microcapsules according to Example 3 are mixed with 90 parts of commercially available high-pressure polyethylene (“Lupolen 2420 F” from BASF), which has a “Melt Flow Index” (MFI) of 0.6 to 0.9 (measured at 190 ° and 21 ° , 2 N), processed and mixed in a rolling mill at 150 °. 3 mm thick plates are produced from the mass obtained under a pressure of 0.123 N / mm 2 and then 1.85 N / mm 2 for 90 seconds each. Flammability is tested according to the U.L. 94 test (Underwriters Laboratories Inc.), it corresponds to the classification V-2.

Example 5

20 parts of microcapsules according to Example 3 (1st part) are mixed in a rolling mill for 3 minutes at about 160 ° with 80 parts of commercially available ABS (Cycolac T 10,000) and for 90 seconds each under a pressure of 0.123 N / mm2, then 1. 85 N / mm2 pressed to 3 mm thick plates. After the flammability test U.L. 94 is the classification of the obtained plates V-0.

Example 6

Microcapsules containing 20 parts of octabromodiphenyl oxide and Sb2Ü3 in a ratio of 5: 3 are processed in the same way as in Example 5 with ABS. In the U.L.-94 test, the classification of the plates obtained is V-0.

N.B. According to the U.L.-94 test, there are three classifications: the best is V-0, the other two are V-1 and V-2. If a substrate is not given a designation, this means that it did not pass the test conditions due to its flammability.

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Claims (4)

666 045 PATENT CLAIMS 1. Flame retardant combination consisting of microcapsules which contain a mixture of a) at least one flame-retardant, halogenated, organic compound and b) an inorganic oxide, hydroxide, borate or phosphate. 2. Microcapsules according to claim 1, which contain a mixture of chlorinated paraffin, octa- or decabromodiphenyl oxide and antimony trioxide. 3. Process for flame-retardant treatment of polymeric organic materials, characterized in that microcapsules according to claim 1 or 2 are introduced into these materials. 4. Flame retardant polymeric organic substances, characterized in that they contain microcapsules as claimed in claim 1 or 2 as a flame retardant.