CS215403B1 - Method of making the electrostatically conductive and antistatic floor covering on the base of polyvinylchloride - Google Patents

Description

CZECHOSLOVAK SOCIALISTIC

REPUBLIC <19) DESCRIPTION OF THE INVENTION 2-5403 (11) <B1) TO THE COPYRIGHT CERTIFICATE i

(22) Registered 04 07 77 (21) (PV 4409-77) (40) Published 31 07 80

INVENTORY OFFICE AND DISCOVERIES (45) Released 01 01 85 (51) Int. Cl.3C 08 J 5/10C 08 L 27/06 (75)

Author of the invention PROKOP BEDŘICH ing., HARNÍK JOSEF, KARAS JOSEF, Napajedla, SURMA JAROSLAV ing., Gottwaldov, BRONSKÁ MILADA ing., Praha (54) Method of production of electrostatically conductive and antistatic flooring on baseipolyvinyl chloride

BACKGROUND OF THE INVENTION The present invention relates to the production of an electrostatically conductive and antistatic polyvinylchloride flooring by mixing granules with an electrically conductive paste, compressing the granules into blocks and splitting and chopping the floor.

There are some special environments - such as hospitals, laboratories, computing centers, specific industries where the use of conventional rubber and plastic flooring is unsuitable. They do not suit their electrical insulation properties with the accumulation of electrostatic charges and the danger of explosions and fires. Therefore, electrostatically conductive or antistatic flooring with the ability to dissipate electrostatic charge is installed in the above-mentioned environment. 104— 1. 109 ohm (electrostatic conductive flooring) resp. surface resistance of not more than 1. 109 ohm (antistatic flooring).

The essence of electrostatic flooring is a material composition or structure that gives them the ability to dissipate electrostatic charges. These properties are essentially achieved by two principal production methods.

The first is the production of floorings from mixtures containing conductive particles. The conductive filler may be carbon black, which has significant disadvantages in terms of both blackness and working problems. moss. Another solution is to overlay the bottom layer filled with soot by a thin, non-conductive layer with the possibility of conventional dyeing. As a result, the use of metallic conductive particles is another solution. The problem here is the size of these particles. The finely powdered metals, in turn, require a high dosage (at least 20%) to achieve the desired electrical insulating properties. This again causes discoloration problems and worsens abrasion resistance. In addition, economic - price aspects are disadvantageous for metal particles.

Another solution of this type is described by Cs. AO 168286, according to which a wear additive of 0.1-0.8 mm to 15% is applied in the wear layer and conductive particles (usually carbon black) of not more than 0.1 mm to 10% in the lower layer. However, the flooring is not sufficiently homogeneous and the metal surface particles act as foreign admixtures. The dyeing and abrasion resistance also deteriorate. The higher conductive particle content in the bottom layer causes sticking difficulties.

The second principle approach is based on pre-homogeneous single-layer materials, typically produced by compression molding. There are also several solutions here. By brit. pat. No. 998,745, a blend of polymeric materials and the necessary ingredients 215403

Claims (2)

2 is hot-rolled and rolled to form a film from which granules are prepared on the granulating apparatus. The granules are coated with a liquid conductive particle paste in a cold drum mixer. Tactured granules are pressed into blocks from which the final flooring slabs are cut. Another method according to British Patent No. 1,121,721 claims the prior preparation of granules as a conductive adhesive composition using a water homopolymic and copolymer emulsion of polyvinyl chloride which contains conductive particles. When the water emulsion is applied to the granules, the water is evaporated, the granules are pressed into blocks and chipped in the floor covering. According to another method (British Patent No. 966,085), carbon black conductive foils and base foils are first prepared by rolling. In a subsequent operation, a laminate is obtained such that the conductive foil is between the two base foils. The layered material is crushed into pieces from which the flooring blocks are imaged. In the view of French Patent No. 1,146,630, the basic material and the conductive material are again prepared by separately rolling and shredding. In a further process, the materials are typically compressed to the final product, with only the conductive material being placed in the lower portion of the mold and a mixture of both crumbs in the upper portion. The advantage of this type of solution is the obtaining of relatively satisfactory electro-insulating properties as well as the choice of characteristic appearance. A disadvantage is that of processes which result from: mixtures of two types of granules, in particular complicated handling. In processes based on the pressing of a conductive coating granule, it is both the energy efficiency (water evaporation from the dispersions), the one-hand handling (sticking) and the risk of the inhomogeneity due to the flow of the liquid paste on the surface of the granules. The aforementioned drawbacks of the prior art are revealed by the method according to the invention, the principle of which is that the mixing of the granules with the electrically conductive paste is carried out in two stages, first of all abnormal temperature, then for 10-20 minutes of 50-110 ° C, with gelatinous conductivity. pastes on the surface of the granules. The process according to the invention has advantages over known processes in that the granules with a conductive layer of gelatinous paste have a non-tacky and non-tacky object. A process for the production of an electrostatically conductive and anti-static polyvinylchloride flooring by mixing polymer granules with an electrically conductive, compressing granules into blocks and chipping by tile chopping, characterized in that mixing the granules with an electrically conductive paste is carried out in stages, first at normal temperature, then {for 10-20 '. Milling at a temperature of 50-110 ° C, 215403 surface, which guarantees the homogeneity of the pressed blocks and tiles and allows easy handling or short-term storage of prepared granules in the event of a technological process interruption. Another advantage is the shortening of the time and the reduction of energy consumption during the pressing, which is important in terms of the productivity of the whole production, since the discontinuous compression following the continuous mixing of the granules with the conductive paste represents a limiting process. By reducing the amount of conductive particles of carbon black or graphite, it will de-regulate the values of through-resistance and leakage resistance even within the desired limits. For values conforming to the requirements of the forthcoming standard, the amount of conductive particles 15-25% by weight calculated on the amount of polyvinyl chloride in the paste should be chosen. ! To illustrate the process of the invention in more detail. the following example is shown. Mix the mixture containing (in parts by weight): suspension polyvinyl chloride 72 bamatocadmium stabilizer 2 stearin 0.3! dioctylphthalate epoxybutyl ester 22; ! TiO2 mixture, yellow GL, ferric yellow 3.7 The pregelatinized agglomerate is homogenized with a screw pelletizer. In an arm mixer, an electrostatically conductive mixture containing (in parts by weight) is mixed: polyvinylchloride paste 35 i lead stearate 0.6 i conductive carbon black 8.2 dioctylphthalate epoxybutyl ester 56.2 The conductive paste is homogenized on a friction machine. First, 97.5 parts of granulate and 2.5 parts of electrostatically conductive paste are mixed in a duplicator casing arm mixer at normal temperature. The mixer is then heated up to 120 ° C, whereby the mixture gradually reaches a temperature of 50-110 ° C within 15 minutes. The granules are pressed in a tray press at a temperature of 170-180 ° C at a pressure of 15-20 MPapo 3 - 5 min. nabloky. The blocks are cooled and removed from the press at 60-80 ° C, chipped and cut to the desired format. Wherein the conductive paste is gelatinized on the granule surface. 2. A process for the production of an electrostatically conductive and anti-static flooring, characterized in that a mixture of paste-forming polyvinyl chloride containing 15-25% by weight of graphite or carbon black, calculated on the weight of polyvinyl chloride, is used as the electrically conductive paste for mixing with the granule.