CS273555B1 - Mixtures with antistatic and self-estinguishing properties - Google Patents

Abstract

For usage in harsh environment, characterized by increased dustiness and possibility of explosion due to the accumulation of static electricity, for instance in coal or even non-coal underground mines, the foils made of plastic must fulfill the requirement of decreasing the combustibility down to the boundary of self-extinguishing; depending on the environment in which they are used, the foils must at the same time also have antistatic or semi-conducting properties. According to the invention, the compound with antistatic and self-extinguishing properties, based on polyolefin and its copolymers or compounds, contains 40 to 80 percent by weight of branched polyethylene, 7 to 15 percent by weight of copolymer vinyl chloride-propylene or 5 to 20 percent by weight of chlorinated or brominated paraffins or cycloparaffins, 7 to 15 percent by weight of antimony trioxide, 0.1 to 3 percent by weight of stabilizing agents based on organostannic esters of lower fatty acids.

Description

(57) For use in harsh environments, characterized by increased dustiness and the possibility of explosion due to static accumulation, such as in coal coal mines, plastic foils must comply with the flame retardant requirement up to the flame retardant limit; depending on the environment of use, the film must also have antistatic or semiconducting properties.

The composition with antistatic and flame retardant properties according to the invention based on polyolefin, its copolymers or mixtures contains 40 to 80 wt. % of branched polyethylene, 7 to 15 wt. % vinyl chloride-propylene copolymers or 5 to 20 wt. % chlorinated or accumulated paraffins or cycloparaffins, 7 to 15 wt. % antimony trioxide, 0.1 to 3 wt. stabilizers based on organotin esters of lower fatty acids.

συ 2 7 3 555 (13) Int. Cl. ⁵ E 21 F 5/16 C 09 K 3/16 en 273555 0.1

The invention relates to mixtures and antistatic and flame retardant properties.

Ventilation of unbroken mine workings ae is performed by so-called separate ventilation by lute strokes. On these lute ducts, fans are installed to convey air, either blowing fresh air onto the face of the excavated work or exhausting worn winds from the face. They use metal lute with flexible. In the case of metal lutes, which are the most widespread, they often deform on flanges and crack metal sheet welds already during their transport from the manufacturer to the mine and then to the workplace itself, during the operation of mining mechanisms or during blasting operations. The flexible lutes then wear the walls. Air leaks through damaged lutes. For longer distances, ie 100 to 300 ra, additional fans must be installed to ensure the safety of mining operations. This leads to significant energy losses, despite the fact that in many workplaces with deteriorated climatic conditions, cooling units have to be deployed in many cases to ensure a satisfactory working climate. Another disadvantage of metal lute strokes is their demanding maintenance and repair. Luten joints and cracked welds are laboriously sealed with replacement materials, such as jute-impregnated guraoasphalt or rubber sleeves, which lose their properties in a corrosive environment.

Some of the improvements are made from metal lutes with plastic-coated inner surfaces. These lutes and rigidly built-in protective layer meet a number of parameters in many parameters, however, the above mentioned damages occur during the manipulation both inside and outside, which are irreversible and their repair in the installed state is practically impossible.

Flexible lute strokes may be unreinforced or reinforced with meshes, fabrics or steel spirals. They are supplied in several dimensions, their purchase price is relatively high and possible repairs of pipes or joints are problematic.

A preferred solution to this problem is to unload the metal pipes with tubular plastic foil. The duct forms the supporting frame, while the foil liner prevents the escape of conveyed air by sealing even unevenness around the joints of the individual parts of the metal or flexible duct. The demanding environment, characterized by increased dustiness and the possibility of explosion due to the accumulation of static electricity, such as in coal and non-coal underground mines, places increased demands on the used films. Above all, it is necessary to reduce the flammability to the limit of self-extinguishing. Depending on the environment of use, the products, i.e. mainly the foil, must have, at the same time as the flame retardant properties, antistatic or semiconductive properties.

There are a number of solutions to the problems of flame retardation of plastics and their modification due to the antistatic properties of the mixture, but until now these problems have been solved mostly separately. For flame retardation, polyolefins are used, for example, by combining halogen compounds with magnesium compounds with a surface-treated magnesium compound or an antimony compound alone or in combination with organic halocompounds (KSS Patent 2,509,435). The latter patent describes samoshášivou polyolefin based mixture, antistatic agents containing guanidine bis-tetrabromo-bisphenol A, brominated diphenyl or also diphenyl ether, chloroparaffins and / or Sb ₂ O ^. A flame retardant antistatic film of polyolefins for the mining, construction and automotive industries is described in German Patent No. 3,313,485. In addition to SbgO4, chloroporaffins or similar retarders, the composition contains hydrophilic substances which cause a wet film layer to form on the film. and forming an antistatic effect.

The novel solution is a mixture with antistatic and sarcosifying properties according to the invention. The invention is characterized in that the mixture contains 40 to 80 wt. branched polyethylene having a flow index of 0.15 to 4 g. 10 min ^- 7 · 7 to 15% by weight of copolymers

CS 273555 B1 vinyl chloride-propylene with a propylene content of 3 to 10% by weight based on the copolymer or 5 to 20% by weight % chlorinated or accumulated paraffins or cycloparsfin, 7 to 15 wt. % antimony trioxide, 0.1 to 3 wt. % of lower-fatty acid organotin esters and an antistatic agent in an amount of 0.01 to 1 wt.

For flame retardation of branched polyethylene, especially for foil production, the most effective flame retardants of the halogenated organic compounds group should be used in combination with antimony trioxide. The retarder must be perfectly melted during processing in the mixture in order to achieve homogeneity and thus efficiency. To ensure thermal stability, the decomposition temperature must be above the processing temperatures of the mixtures. Organic flame retardants with an increased halogen content, in particular chlorine, are preferred in this regard. The advantage of their use lies mainly in the compatibility with the base polymer, good dispersibility and retarding effects while ensuring acceptable health aspects. To ensure maximum dispersion of antimony trioxide, it is preferred to use branched high molecular weight polyethylene. When using said flame retardants, an oxygen value of 23 to 26 is expected, which virtually ensures flame retardancy.

Addition of antistatic agents such as hydroxy, amine by amide groups, or ether group terciální.aminoskupinou possible to reduce the surface resistivity of the LO ¹ _{and the} amount to values in the range of 10 to 10 @ ¹¹ ohms, which meets the conditions with demanding antistatic treatment flat products such as foil. Then there is minimal electrostatic charging or the products do not charge at all.

The following examples serve to illustrate the invention in more detail.

Example 1

The mixture with antistatic flame retardant properties contains 80.00 wt. branched polyethylene with a flow index of 0.3 g.10 min ^-1

7.75% wt. vinyl chloride-propylene copolymer (containing 3,5% by weight of propylene with a K value of 58, a chlorine content of up to 55,2%)

7.75% wt. % antimony trioxide 4.00% wt. of color, toner

0.30% wt. stannic stabilizer (designation standard) for sample ref. Butyl tin carboxylic acid ester

0.20% wt. % antistatic agent based on alkylolamides of fatty acids (25 wt.

oleic acid monoethanolamide, 70 wt. oleic acid diethanolamide, 5 wt. triethanolamine oleic acid soap).

The mixture was prepared on a calender and the granulate produced was processed on a 90 mm screw extruder, a 500 mm die, into a 1000 mm wide and 0.15 mm thick composite film. The films intended for lute tensile coal mines had the corresponding properties, as shown in Table 1, in particular this material could be categorized as having a reduced flammability and flame retardant effect (Category B).

Table 1: Film properties

Sample E. Max. el. field (kV.cml) Half-life of el. cartridges (with) Bbef. state. friction kinet. Combustibility DIN 53 282 Standard 5.3 not discharging 0.25 0.266 (B) 1 2.9 25 0.22 0.23 (B)

Measurement method on PD-28 electrification apparatus, VIIGPT methodology.

CS 273555 Bl

Example 2

No kneaders were processed mixture of composition:

43.35

0.4

0.25 wt. branched polyethylene having a melt index of 2 min G.10 ^-% by weight, ethylene vinyl acetate copolymers containing 12% VAC group flow index G.10 2 min ^-1.

% wt. vinyl chloride-propylene copolymer (containing 3,5% propylene, of a K value of 58, a chlorine content of up to 55,2% by weight, antimony trioxide, by weight, tinnyl stabilizer - octyltin carboxylic acid ester by weight, antistatic alkylolomide fatty acid reagent (25% by weight of rapeseed oil monoethynolamides and 75% by weight of rapeseed diethanolamides).

The granulate was processed on an operating device to 0.12 mm thick films, the application areas of these films being insulation and films for special applications. The material can be categorized as having a low flammability and a flame retardant effect; The jok shows the table is well antistatic modified.

Table 2; Properties of foils

Max, el. field (kV.cm ~ l) Half-life of el. cartridges (with) Koef. state. friction kin. Flammability DIN 53 382 2,0 10 0.27 0.23 (B)

The mixtures according to the invention can be used not only for the production of films for the construction of lute pulls in mines, but also for the production of water seals for blasting operations, for the production of charging hoses used for non-tear-free blasting operations in mines and for conducting conductors.

Claims (1)

SUBJECT OF THE INVENTION Mixture having antistatic and self-igniting properties based on polyolefins, copolymers or mixtures thereof, characterized in that it contains 40 to 80 wt. % of branched polyethylene having a flow index of 0.15 to 4 g. 10 min ^-1 , 7 to 15 wt. % vinyl chloride-propylene copolymer having a propylene content of 3 to 10 wt.% based on the copolymer or 5 to 20 wt. chlorinated or accumulated paraffins or cycloparaffins, 7 to 15 wt.% antimony trioxide, 0.1 to 3 wt. % stabilizers based on organotin esters of fatty acids and an antistatic agent in an amount of 0.01 to 1 wt.