PL189208B1 - Method of producing slow-burning polypropylene fibres - Google Patents

Abstract

1. The method of producing slow-burning polypropylene fibres out of melted fibre-forming polypropylene, containing flammability-reducing agents. Unique characteristics: A synergic mixture of combustion-retarding agents is introduced into fibre-forming propylene. The synergic mixture contains: 0.1 to 25 percent by mass (of the polymer) of compounds containing atoms of bromine and/or chlorine and/or phosphorus and/or nitrogen and 0.0001 to 10 percent by mass (of the polymer) of compounds of aluminium and/or titanium, in the form of oxides or salts. The mixture may contain 0.1 to 10 percent by mass (of the polymer) of an additional antimony compound, preferably antimony trioxide. The weight ratio of the synergic mixture components should be maintained within the range between 25000:1 and 1:2.5. Then, the resultant mixture is used to form fibres at the temperature of at least 220 degrees C at the rate of at least 400 m/min.

Description

The subject of the invention is a method of producing flame-retardant polypropylene fibers.

Known methods of producing flame-retardant polypropylene fibers consist in introducing into polypropylene, prior to the fiber forming process, flame retardants such as: aromatic hydrocarbons containing halogen, especially bromine, aliphatic or aromatic phosphates or phosphazenes also containing halogens. In order to obtain the flame retardant effect, antimony compounds are also introduced. Methods of reducing the flammability of polypropylene fibers are described, among others, in the journal "Polimery", vol. 19, no. 11, pp. 521, 1974, in M. Ahmed's monograph "Polypropylene Fibres - Science and Technology", 1982 and in the conference materials "Flame Retardants'96", London, 1996 , as well as in Polish patent description No. 98143 and in the descriptions of US patents No. 3650300, 3927145, 3988296, 4532278, 4774044.

In the known methods, in order to obtain the proper flame retardant effect of the fibers, it is necessary to introduce significant amounts of flame retardants, which adversely affects the rheological and processing properties of polypropylene and, consequently, deteriorates a number of functional properties of the fibers produced, such as strength or color.

The method of producing flame retardant polypropylene fibers according to the invention consists in introducing a synergistic flame retardant system consisting of compounds containing bromine and / or chlorine and / or phosphorus and / or nitrogen atoms in the amount of 0.1 to 25% by weight of the fiber-forming polypropylene. based on the weight of the polymer and aluminum and / or titanium compounds in an amount from 0.0001 to 10% by weight with respect to the weight of the polymer, with the possible addition of an antimony compound, preferably antimony trioxide, in an amount of 0.1 to 10% by weight in the ratio to the weight of the polymer, keeping the weight ratio

189,208 components of a synergistic system from 25,000: 1 to 1: 2.5. Then, from the obtained mixture, fibers are formed at a temperature not lower than 200 ° C, at a speed not lower than 400 m / min.

Brominated aliphatic or aromatic hydrocarbons, phenols, such as tetrabromobisphenol, tribromoneopentyl, chloroparaffins, dibromostyrene grafted copolymers, aryl phosphates or melamine derivatives are used as compounds containing bromine and / or chlorine and / or phosphorus and / or nitrogen atoms.

The method according to the invention also consists in that compounds containing bromine and / or chlorine and / or phosphorus and / or nitrogen atoms can be introduced into the fiber-forming polypropylene in the form of a granular concentrate on a polyethylene and / or polypropylene support.

According to the invention, the mixture of components of the synergistic system can also be introduced into the fiber-forming polypropylene in the form of a granular concentrate on a polyethylene and / or polypropylene support.

The use of a synergistic flame retardant system for polypropylene fibers in the method according to the invention results in a correspondingly greater flame retardant effect than when the system components are used separately. In addition, the introduction of the synergistic system into polypropylene fibers in the amount necessary to achieve the intended reduction of their flammability significantly reduces the negative effects of deteriorating their strength, color or performance properties in relation to analogous polypropylene fibers produced with the participation of individual components of the synergistic system, with comparable flame retardance.

The advantage of the method according to the invention is the possibility of producing flame-retardant polypropylene fibers with a predetermined oxygen index value with the use of less flame retardants as a result of introducing into the fiber-forming polypropylene, in addition to the flame retardants, the synergistic component consisting of aluminum compounds, titanium compounds or a mixture thereof. These compounds cooperate in inhibiting the burning process of polypropylene material, increasing the effectiveness of flame retardants.

The advantage of the method is also the possibility of introducing a synergistic system or a flame retardant - a component of this system in the form of a granular concentrate - into the fiber-forming polypropylene.

The method according to the invention is used in the chemical fiber industry and in the textile industry for the production of flame-retardant polypropylene fibers intended for products meeting the relevant fire protection requirements.

To determine the flammability of polypropylene fibers, the limit oxygen index - LOI method was used. The method consists in the fact that a bundle of fibers weighing 0.2 g is clamped horizontally in the measuring column, then the flow of the oxygen-nitrogen mixture is turned on and after a minimum of 30 seconds the bundle of fibers is set on fire in its half length and the smallest volume content is determined. oxygen in the oxygen-nitrogen mixture, at which complete combustion of the fiber bundle occurs.

The following examples illustrate the subject matter of the invention.

Example 1 0.2 kg of bis (2,3-dibromopropylether) tetrabromobisphenol A and 0.1 kg of titanium dioxide were introduced into a rotary mixer containing 20 kg of polypropylene granules and mixed for 10 minutes. Then, from the mixture prepared in this way, fibers were formed on an extruder spinner at the temperature of 240 ° C and the speed of 500 m / min. The produced crude fibers were stretched using a 3-fold stretch.

A polypropylene fiber with a limiting oxygen index LOI = 21.1% was obtained.

For comparison, in an analogous manner, a fiber was produced from polypropylene and polypropylene with the addition of 1% by weight of bis (2,3-dibromopropylether) tetrabromobisphenol A. The limit oxygen index of the obtained fibers was 18.5% and 20.8%, respectively.

Example II. 3 kg of bis (2,3-dibromopropylether) tetrabromobisphenol A and 0.1 kg of titanium dioxide were introduced into the mixer containing 20 kg of polypropylene granules and mixed for 5 minutes. Then, from the obtained mixture, fibers were formed as in Example 1.

Polypropylene fibers with the ultimate flammability index LOI = 22.9% were obtained.

189 208

Example III. The granular concentrate of bis (2,3-dibromopropylether) tetrabisphenol A and titanium dioxide on a polyethylene-polypropylene carrier was introduced into the mixer containing 43.2 kg of polypropylene granules, then the whole was mixed for 10 minutes, and then the fibers were formed as in Example I. Concentrate made from a mixture of: 0.3 kg of polyethylene granules, 4.5 kg of polypropylene granules, 0.48 kg of bis (2,3-dibromopropylether) tetrabromobisphenol A and 1.2 kg of titanium dioxide, from which a line was extruded at a temperature of 200 ° C, and after cooling the line was granulated.

The obtained polypropylene fibers with the limit oxygen index LOI = 21.5%.

Example IV. 14.8 kg of polypropylene and a mixture of 2 kg of 40% tr (tribromoneopentyl) phosphate concentrate in polypropylene, prepared on a compounder device, and 0.016 kg of aluminum trioxide, were introduced into the mixer. The mixture was stirred for 5 minutes, then the obtained mixture was formed into fibers as in Example 1.

The obtained polypropylene fibers with the limit oxygen index LOI = 20.5%.

Example 5 The mixture of: 0.02 kg of aluminum trioxide, 0.1 kg of titanium dioxide, 0.8 kg of antimony trioxide and 2.5 kg of 40% tribromoneopentyl phosphate concentrate in polypropylene was introduced into a mixer containing 18.5 kg of polypropylene granules. The mixture was stirred for 10 minutes, then the obtained mixture was formed into fibers as in Example 1.

Polypropylene fibers with the limit oxygen index LOI = 22.2% were obtained.

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Claims (4)

Patent claims A method for producing flame retardant polypropylene fibers from a fused fiber-forming polypropylene containing flame retardants, characterized in that a synergistic flame retardant system consisting of compounds containing bromine and / or chlorine and / or phosphorus and / or nitrogen atoms is introduced into the fiber-forming polypropylene, in an amount of 0.1 to 25% by weight with respect to the weight of the polymer and of aluminum and / or titanium compounds in the form of oxides or salts, in an amount of 0.0001 to 10% by weight relative to the weight of the polymer, with the possible addition of an antimony compound, preferably antimony trioxide, in an amount of 0.1 to 10% by weight relative to the weight of the polymer, while maintaining the weight ratio of the components of the synergistic system from 25,000: 1 to 1: 2.5, then the obtained mixture is formed into fibers at a temperature not 220 ° C, at a speed of not less than 400 m / min. 2. The method according to p. A process as claimed in claim 1, characterized in that brominated aliphatic or aromatic hydrocarbons, phenols, such as: tetrabromobisphenol, tribromoneopentyl, chloroparaffins, dibromostyrene grafted copolymers, aryl phosphates or melamine derivatives. 3. The method according to p. A process as claimed in claim 1, characterized in that the compounds containing bromine and / or chlorine and / or phosphorus and / or nitrogen atoms are introduced into the fiber-forming polypropylene in the form of a granular concentrate on a polyethylene and / or polypropylene carrier. 4. The method according to p. The method of claim 1, characterized in that the components of the synergistic system are introduced into the fiber-forming polypropylene in the form of a granular concentrate of their mixture on a polyethylene and / or polypropylene carrier.