KR0144336B1 - Polymer fire retardant - Google Patents

Abstract

The present invention relates to novel compositions useful as flame retardants in polymers such as polyethylene, polypropylene, polystyrene and nylon. Flame retardant compositions useful for providing flame resistance to synthetic polymeric materials include solid compositions precipitated from an aqueous mixture of sulfate or phosphate oxyacids, amine surfactants.

Description

[Name of invention]

Refractory for Polymer

[Field of Invention]

The present invention relates to novel compositions useful as flame retardants in polymers such as polyethylene, polypropylene, polystyrene and nylon.

[Background of invention]

Increasing public safety expectations have led government agencies to raise regulations and legislation on flammable smoke risks associated with ignited synthetic polymeric materials. It is particularly firm for thermoplastics produced by the rapid extrusion process. Commercially available flame retardants for extruded polymeric materials are predominantly hydrogen halides and exhibit at least five major disadvantages: (1) intrinsic toxicity, (2) flame retardant only after evaporation by thermal action, (3) corrosive and It produces highly toxic vapors, (4) does not suppress smoke known to cause death by fire, and (5) often requires the presence of antimony oxide, known as a dangerous carcinogenic compound. To improve the situation, the United States National Materials Advisory Board encourages the development of carbide-forming flame retardants that reduce or eliminate the formation of all forms of vapor upon exposure to flames. .

Efforts have been made to develop flame retardants in the form of non-halogenated hydrocarbons for extrudable thermoplastic materials. W. on November 13, 1979. ratio. United States Patent No. 4,174,343 to W. B. Hardy et al. Describes polyolefin compositions containing a mixture of disphosphonate and ammonium polyphosphate as flame retardant. Also described are polyolefin compositions containing 20-40% by weight of dicyanopentaerythritol diphosphonate. In particular, flame retardants are used to make the homopolypropylenes flame retardant, but can also be applied to high polymers with 10 to 15% of ethylene or (iso) butylene.

U.S. Patent No. 4,312,802 to G. Bertelli, issued January 26, 1982, discloses 100 parts of thermoplastic polymer (a), ammonium or amimophosphate (b) 5 to 30 parts and component (b). A self-extinguishing polymer composition comprising 3 to 20 parts of an N-containing organic compound (c) that forms a carbonaceous non-droplet mass upon heating in the presence of is described. Flame retardant systems can be used with olefin (co) polymers such as polypropylene, polyethylene, ethylene-propylene copolymers, polystyrene, ABS, polyethylene terephthalate, polybutylene terephthalate, polycarbonate and polyamide. These olefin (co) polymers impart superior acid plasticity and do not corrode the processing equipment and do not generate toxic fumes and gases upon firing.

British Patent No. 1,603,123, issued to Johnson Trading Co. on November 18, 1981, contains an aqueous solution of ammonium sulfate (a), ammonium phosphate (b) and ammonium diphosphate (c). Flame retardant and flame retardant compositions are described. It may also be in the form of an aqueous anhydrous mixture. The composition comprises a binder, for example an alkali metal silicate (up to 1 wt.%): A water repellent additive such as sodium stearate (up to 0.5 wt.%): An additional ammonium salt (up to 4 wt.%) Such as sulfamate or meta-borate: Hypochlorite (0.01 wt% or less): chloride salt (weight ratio of hypochlorite salt: chloride salt = 1: 8 to 1:20) and Na ₂ HPO ₄ . The compositions are known to provide balanced protection against flame propagation and melting while meeting health and hygiene conditions.

U.S. Patent Nos. 2,287,597 (1943), 2,464,342 (1949), 2,514,268 (1950), and 2,536,988 (1951) describe melamine-containing flame retardants.

[Summary of invention]

The present invention relates to flame retardant compositions comprising a mixture of phosphates, amines and surfactants useful for imparting flame retardancy to synthetic polymeric materials.

Flame retardant compositions useful for imparting flame retardancy to polymers include oxyacids, ethylenediamine, p-phenylenediamine, m-xylene-α, α selected from the group consisting of phosphoric acid, ammonium monophosphate, ammonium diphosphate, sulfuric acid, and ammonium sulfate Amine and sodium lauryl sulfate, polyvidone, sodium, selected from the group consisting of '-diamine, 2,4,6-triamino-1, 3,5-triazine, 2-aminopyridine, diethylenetriamine and urea Solid compositions precipitated from an aqueous mixture of surfactants selected from the group consisting of alkylbenzenesulfonates, sodium palmitates and detergents sold under the trade name Tide.

Flame retardant compositions useful for imparting flame retardancy to polymers include solid compositions precipitated from a mixture of monobasic ammonium phosphate, 2,4,6-triamino-1,3,5-triazine and sodium lauryl sulfate.

Processes for preparing flame retardant additives useful for imparting flame retardancy to synthetic polymeric materials include: a) about 30 to 70 weight percent, based on the total weight of the mixture, of phosphoric acid, ammonium monophosphate, ammonium diphosphate, sulfuric acid, ammonium monosulfate and One oxyacid selected from the group consisting of: b) from about 30 to 70% by weight, based on the total weight of the mixture, of ethylenediamine, p-phenylenediamine, m-xylene-α, α'-diamine, Whole amine and c) mixture selected from the group consisting of 2,4,6-triamino-1,3,5-triazine, 2-aminopyridine, diethylenetriamine, urea and mixtures thereof From about 0.25 to 10% by weight, respectively, from the group consisting of one surfactant, selected from the group consisting of conventional detergents such as sodium lauryl sulfate, polyvidone tide, and mixtures thereof Preparing a solid composition precipitated from a mixture of three reagents, wherein this method dissolves oxyacid in a minimum volume of boiling water, adds amine to the boiling water and oxyacid, and then completely precipitates the solid composition. The boiling mixture is heated and stirred until it is filtered, the composition is filtered from the mixture, and then the surfactant is added, and the crude powder is ground to be a flame retardant additive.

Detailed description of the invention

The present invention relates, in particular, to carbide forming flame retardants for preventing all forms of vapor formation in hydrophobic polymeric materials such as polyethylene, polypropylene, polystyrene, nylon, ABS, lattes and synthetic rubbers.

The carbide forming flame retardants have been formulated to provide carbide forming flame retardancy when exposed to flame while being suitable for most plastic manufacturing methods and withstanding the relatively high temperatures typically required for plastic molding or extrusion. Flame retardants of the present invention can withstand the temperatures of 350-550 ° F. encountered in thermoplastic injection molding machines without becoming unstable or loss of flame retardancy.

Carbide-forming flame retardants of the present invention typically comprise a solid composition precipitated from an aqueous mixture of oxyacids, amines and surfactants. Flame retardants did not volatilize upon degradation and polymers containing flame retardants preserved about 99% of their weight upon exposure to flame. Typically, the flammable polymerizer is 5 to 10% ash upon exposure to flame.

Suitable oxyacids include phosphoric acid, ammonium monophosphate, ammonium diphosphate, sulfuric acid, ammonium monosulphate or hydrated forms of these oxyacids.

Suitable amines are ethylenediamine, p-phenylenediamine, m-xylene-α, α'-diamine, 2,4,6-triamino-1,3,5-triazine, 2-aminopyridine, diethylenetriamine And urea.

Suitable surfactants include detergents marketed under the trade names Sodium Lauryl Sulfate, Polyvidone, Sodium Alkylbenzenesulfonate, Sodium Palmitate and Tidra.

Many chemical compounds described above have another name. For the purposes of the present invention and to aid the understanding of the present invention, first ammonium phosphate is also known as monobasic ammonium phosphate, ammonium diphosphate is also known as dibasic ammonium phosphate, and ethylenediamine is also 1 Is known as, 2-ethanediamine, polyvidone is also known as 1-vinyl-pyrrolidinone polymer or poly [1- (2-oxo-1-pyrrolidinyl) ethylene], and ammonium monosulfate is also known as Ammonium bisulfate is known and urea is also known as carbonyl diamide.

The present inventors have chemically added to various acid forms of sulfates and / or phosphates to form insoluble products that exhibit the typical carbide-forming catalysis of phosphates and sulfates and can be mixed with various plastics in the same manner as well as stable at high temperatures. The group of amines was identified.

While not wishing to be bound by theory or beneficial interpretation, the inventors found that a fixed amount of named amines, when added to varying amounts of acid phosphate and / or acid sulfate, resulted in non-stoichiometric multiple addition products. . In particular, the nonstoichiometric addition of 2,4,6-triamino-1,3,5-triazine and ammonium monophosphate has been investigated in detail, in which case the phosphate salts have two acid protons and the amine has 3 Amino groups. Obviously. Acid protons can hydrogen bond with basic amino groups in a wide range of bond ratios. At the first extreme, each monophosphate hydrogen bonds with two molecules of 2,4,6-triamino-1,3,5-triazine. At the second extreme, each 2,4,6-triamino-1,3,5-triazine is hydrogen bonded to three monophosphate anions. At the first extreme, the unbound amino group is at maximum, and at the second extreme, the unbound phosphate proton is at its maximum. Similar binding ratios are each 2,4,6, -triamino-1,3,5-triazine hydrogen bonded to the three monophosphates, and each monophosphate is two 1,3,5-triamino-2, It originates from a sheet-like structure that binds 4,6-triazine molecules. This structure requires two 1,3,5-triamino-2,4,6-triazines to bind three monoammonium phosphates. This theoretical review explains the nonstoichiometry found for the compounds described herein and this explanation explains why active flame retardants are not described as pure chemical compounds.

Effective compositions contain 57% by weight of ammonium phosphate monobasic, 42% by weight 2,4,6-triamino-2,4,6-triazine and 1% by weight tide (trade name) in the minimum volume of boiling water required to dissolve the phosphate do. The resulting precipitate is filtered off, dried and then ground to a useful flame retardant.

Other effective detergents are sodium alkylbenzenesulfonate and sodium palmitate.

Another preferred composition contains 57% by weight of ammonium phosphate monobasic, 42% by weight of 1,3,5-triamino-2,4,6-triazine and 1% by weight of polyvidone in the minimum volume of boiling water required to dissolve the phosphate do. The resulting precipitate is filtered off, dried and then ground to a useful flame retardant.

Further preferred compositions contain 43 weight percent phosphoric acid, 56 weight percent 2,4,6-triamino-2,4,6-triazine and 1 weight percent polyvidone.

EXAMPLE

[Laboratory Preparation of Flame Retardants]

1 mol (126 g) of melamine powder (American Cyanamide) is sprinkled in a hot (100 ° C.) solution of 2 mol (230 g) of ammonium monophosphate dissolved in a minimum volume of boiling water (133 g). Heat the mixture and stir for about 20 minutes. The white precipitate is filtered and dried to yield 318 g of product which is rapidly melted at 310 ° C.

About 9 lb of low density polyethylene (LDPE) and about 1 lb of melamine phosphate (MP) (white precipitate obtained from the reaction) are mixed at 350 ° F. under surfactant excipient. The product passed parts C, D and E of the UL94HB and UL945V tests for flammability of plastic materials. Untreated polyethylene failed all these flammability tests with a wide margin.

The flammability test performed uses 2.5 x 0.5 x 0.12 inch tiles extruded from LDPE containing 10 wt% inferior grade MP and pure LDPE. Microscopic assays of LDPE-MP mixtures show adequate but incomplete mixing due to inadequate grinding of MP and exclusion of suitable surfactants upon mixing.

The standard test, described in the next two paragraphs, is duly carried out using tiles of 5.0 × 0.5 × 0.25 inch or 6.0 × 6.0 × 0.25 inch.

The Horizontal Burning Test, UL94HB, measures the rate of combustion when an edge is heated for 30 seconds by a Bunsen burner flame. Untreated LDPE burns at a rate of 5 inches per minute due to additional flame propagation due to flame droplets. LDPE containing 10% MP is burned at 1.2 inches per minute due to the absence of flame propagation due to flame droplets. The UL94HB test requires only a burn rate of less than 3.0 inches per minute for samples thinner than 0.125 inches.

The Vertical Burning Test, UL94-5V, consists of (a) bottom corner, (b) bottom corner, (c) side edge, (d) top surface and (e) bottom surface for five five seconds each. Application is used to determine the duration of the flame after burning with the Bunsen burner flame. If combustion stops within 60 seconds without flame drops, the test is passed. Untreated LDPE burns completely due to flame viscosity in all tests. LDPE containing 10% MP was found not to pass tests (a) and (b) to a minimum, to pass test (c) to a minimum, and to easily pass tests (d) and (e). . In tests (a), (b) and (c), LDPE-MP exhibited a thin trail of flame only along the burned edges, which were immediately present with slight ventilation by dialogue or hand movement. Extinct In contrast, untreated LDPE burns violently and completely due to flame droplets, even in normal ventilation. In tests (d) and (e), LDPE-MP did not ignite and burn at all when observed after removing the burner. Flame drops observed in all tests with untreated LDPE were not observed in any tests with LDPE in MP treated form.

In the case of burning with flames, low density polyethylene has a essentially low melting point which causes the flame to develop by the liquid flow and burn vigorously. Melamine phosphate (MP) does not change its low melting point, but forms sufficient carbide to limit the flow by combustion and melting.

Polyethylene, polypropylene and nylon containing 15% by weight melamine phosphate flame retardant containing 1% by weight sodium alkylbenzenesulfonate passed the UL94HB combustion test and all five parts of the UL94-5V combustion test.

[fair]

Incorporating a flame retardant material, such as described herein, into a plastic material is performed by mixing the finely divided flame retardant with the molten plastic. Important factors in making a commercially available product include the particle size of the flame retardant, the choice of surfactant material used to produce the flame retardant, and finally the particle size of the feedstock plastics.

First, the flame retardant must be ground to a particle size of less than 50 microns or in some applications less than 5 microns. There are two reasons for this. Flame retardants act as heterogeneous catalysts whose effects depend on the surface of the flame retardant. Fine particles have a larger surface area than coarse particles. Coarse flame retardant particles also degrade the physical appearance and physical properties of the product.

Secondly, the flame retardant must contain about 1% by weight of surfactant, which, when mixed with the molten plastic, prevents the aggregation of the flame retardant. The choice of surfactant depends on the type of plastic being flame retardant.

Third, feedstock plastics must be cut or ground to a particle size of less than 1000 microns to obtain a homogeneous mixture of plastics and flame retardants when the plastic and flame retardant are mixed as a melt. These requirements arise primarily from commercial demands to minimize melt durations.

The flame retardant plastic material contains 5 to 20% by weight of flame retardant. In general, plastics containing 20% by weight of the flame retardant described herein have an almost unattainable self-extinction using more weight%. In addition, plastics containing less than 5% by weight of a flame retardant do not improve in flammability.

In light of the foregoing description, those skilled in the art will recognize that many variations and modifications may be made in the practice of the present invention without departing from the object or scope of the invention. Therefore, the scope of the present invention should be constructed in accordance with the scope defined in the following claims.

Claims (5)

(a) from about 30 to 70% by weight, based on the total weight of the flame retardant composition, of oxyacid selected from the group consisting of phosphoric acid, ammonium monophosphate, ammonium diphosphate, sulfuric acid, ammonium monosulfate, and mixtures thereof, ethylenediamine, p -Phenylenediamine, m-xylene-α, α'-diamine, 2,4,6-triamino-1,3,5-triazine, 2-aminopyridine, diethylenetriamine, urea and mixtures thereof About 0.25 to 10% by weight of sodium lauryl sulfate, polyvidone, sodium alkylbenzenesulfonate, based on the total weight of the solid particle composition precipitated from an aqueous mixture with an amine selected from the group consisting of (b) a flame retardant composition, A flame retardant composition for synthetic polymeric materials comprising a surfactant selected from the group consisting of sodium palmitate and mixtures thereof. The method of claim 1, wherein the oxyacid comprises 57 to 66% by weight of ammonium phosphate, 42 to 33% by weight of 2,4,6-triamino-2,4,6-triazine and 1% by weight of sodium alkylbenzenesulfonate. Composition. The composition of claim 1 wherein the particle size of the particle composition (a) is less than 50 μ. (a) about 30 to 70% by weight of the additive, about the total weight of the oxyacid and the additive selected from the group consisting of phosphoric acid, ammonium monophosphate, ammonium diphosphate, sulfuric acid, ammonium sulfate and mixtures thereof 30 to 70% of ethylenediamine, p-phenylenediamine, m-xylene-α, α'-diamine, 2,4,6-triamino-1,3,5, -triazine, 2-aminopyridine, A solid composition precipitated from a mixture with one amine selected from the group consisting of diethylene triamine, urea and mixtures thereof, and (b) about 0.25 to 10% sodium lauryl, based on the total weight of the additive Adding one surfactant selected from the group consisting of sulfate, polyvidone, sodium alkyl benzenesulfonate, sodium palmitate, and mixtures thereof, wherein the oxyacid is dissolved in a minimum volume of boiling water, and The amine is added to the oxy acid, then the boiling mixture is heated and stirred until the solid composition precipitates, the solid composition is filtered from the mixture, then the surfactant is added and the solid composition is finely divided to be a flame retardant additive to give a synthetic polymeric material. Method for preparing flame retardant additive for The method of claim 4, wherein the solid composition is ground to a particle size of less than 50 μ.