CS214208B1 - Foil made from modified polyvinyl chloride - Google Patents

Abstract

The invention relates to films made from modified polyvinyl chloride having antistatic properties which are resistant to the action of hydrocarbons and are permeable to at most 2 g/m<2>/day of the test liquid in accordance with DIN 53532, and to the process for the preparation of these films. The material is intended for lining cisterns and containers for storing hydrocarbons of the gasoline type. The films of the invention meet the required electrical and mechanical values for the said application with appropriate stability and have a diffusion coefficient of from 2 x 10<-12> to 3 x 10<-13> m<2>s<-1>, a dimensional stability of up to +/-1% on conditioning at 80 DEG C for 6 hours, a tensile strength of at least 12 MPa and a maximum electrical surface resistance of 10<6> ohms. The films are produced by rolling and extrusion at 160-190 DEG C with stabilisation and cooling, with tension and deformation during cooling being kept within the limits from 0.2 to 2.0%.

Description

The present invention relates to modified polyvinyl chloride films having antistatic properties which resist the action of hydrocarbons and to a process for the manufacture of such films.

The materials used for unloading tanks and tanks for flammable liquids are required to have a surface and continuous electrical resistance to ensure reliable removal of the electrostatic charge. It is found that to meet this requirement muuí be the value of the surface resistivity plastics sheet ^tu reflux for i ^ d ^ e na · s ^ ate ^ u ^ uřilovotá the ^PU gasoline ^with lower ⁿ EŽ lo ^ er. The achievement of the stated value of electrical resistance is possible by using the addition of conductive fillers in mixtures, i.e. metal powders or conductive types of carbon black, as described, for example, in U.S. Pat. No. 168'286, British Patent Specification No. 845,871 or U.S. Pat.

862 056.

A disadvantage of the known films produced by conventional processes is that their electrical properties are not stable in contact with stored hydrocarbons - their surface resistance increases by 2 to 4 orders after some time. In an attempt to compensate for this deficiency by increasing the content of conductive carbon blacks, the permeability of the films so produced is increased, as a larger amount of carbon blacks greatly facilitates the diffusion of hydrocarbons. Mechanical properties will also deteriorate.

The purpose of the invention is to create maateiál whose surface electric resistance · after reaching the equilibrium state of her ^^ ^ i 10 ⁵ ohms per p ^r i s ^ s ^ ^l and the solid ESPO ^{least 12} MPa and ^even ρroppžínodt • 2 'for test liquid (DIN 53.532) not more than 2 g / m / day.

It has been found that these requirements ^ v ^ ^f satisfies Olie, thereof ^from nature is that its ^d œ sets Kaspersky AV ifuzni ^to 12 -3 2 -1 + _f · Is ficient of 2.10 to 3.10 ms, dimensional stability between - 1 · after temperxce 6 hours at 80 C, fortresses' ^t V ^ ^h and in the above: no ^{12 M} Pa, and the MMXI ^ ^h o ^d ew note povrc ^{h h} oe o ^ ^^ Ricker oru · ¹⁰⁶ ohms. These lie ^{tert l} prepared from the extrusion-Neto cováním · processed at temperatures ^{from 160 to 190} ° ^{C, CEM.} tension x deformation during cooling is maintained in the range 0.2 - 2.0

In the production of films of desired properties, the most important factor, besides the perfect mixing of the mixture in the kneader or extruder, is the mild elongation at draw-off x cooling. This finding, on which the present invention is based, is illustrated by the following table of the surface resistance x elongation of the 10% carbon black polyvinyl chloride film.

elongation% surface resistance, ohm

6.10

^{1, 5,} 10 ⁵

For practical use, the films produced according to the invention are laminated with other layers by conventional processes between rollers or by coextrusion. Laminated foils for unloading tanks x below are also preferred. reinforce eg with an inserted reinforcement grid.

The following examples illustrate the invention in more detail.

Mixture A (in parts by weight):

Polyvinyl chloride 50.3 Dioctyladipate 13.0 Adipic acid ester and butanediol 14.0 Bвtaaiennkгrtltntrilový rubber 10.0 A stabilizer is present 4.8 E ^ ter mesoic acid 0.7 Soot 8.0

Mixture B (in parts by weight):

Internal plasticized polyvinyl chloride (copolymer with adipic acid ester and

butanediol) 64.3 Dioctyladipate 12.0 B is a stabilizer 4.0 Butaaienn ^k krtlontrilový rubber 10.0 Mint acid esters 0.7 Soot 8.0

Example 1

Mixture A resp. B is preliminarily mixed in a fluid mxcKačcce, the Plastics and homoseeizuje planetary machine and extrusion through a flat die (temperature of the melt at the die exit ¹⁶⁰ to 200 ° C) produces a mixture ^s of Otto film. The embossed films are passed through the liner and the withdrawal roll, whereby at the plastic deformation temperature of the material the foil stress must not cause a deformation greater than 2%. The foils produced from A and B have the following characteristics:

Permeability for test. apalinu ^to max. ² g / m ² / day at 2 ⁰ ° C after 90 days

Surface el. resistance max. W ⁵ Ohm Fortress thrust min. 13 .MPa Ductility min. 250% Fortress discord min. 65%

Example 2

According to recipes A and B, the binder is mixed in a fluidic mixer, processed into granules and foils are produced at the same temperature as in Example 1. The properties of the films produced by this process correspond to those of Example 1.

Example3

In the fluidized-Bo Yin ^{é é} active mixer with ^p s ^{p s} prášlcovi rav ^ The mixtures A and B. Srmcsi the jacket ^for uji and hom ^ e ^ d in the take off ^or ontinu Condominium functioning hn ^{j n} for the _ ^or tepkty ^140-175 . ° C ^and at ^what VA ^{j c} l i ^L i ^{nce is} fabricated film ^e having a thickness 0.35 to 0.45 mm. These foils are laminated · - the ^- ^ pl ^ y ^{from 180 to 200} ° C on a welding machine, again not cause deformation of greater than 2

The films produced exhibit similar properties as in Example 1.

Claims (2)

SUBJECT OF THE INVENTION CLAIMS 1. Modified polyvinyl chloride film having a content of 6-: 12 wt. of hydrocarbons 2> and having a test fluid permeability not greater than 2 g / m · / day. characterized in that its diffusion coefficient is 2.10 ^- - 3.10. ¹ m ² s ^1, dimensional stability between - 1 · after 6 hours annealing at ⁸⁰ ° ^{C, the} evnos ^t V and ^H at a higher than ¹² MPa and am ^ ^ ^ i.má]. ^{Ry p} value ovrc ^h o ^eh by EJ-rich ^ e ^ he resistance of 10 ohm ·. 2. A process for producing the film according to claim 1 by rolling or extrusion stabilization and cooling, ^{characterized} in that ^brand Eny ^{by Z} e te ^pl OTA Rácová ^{P and} N ⁱ is ^{160 to 190} ° C, wherein ^{T s} p h. and deformation ^of cKlazen ^s is maintained in the range; 0.2 - 2.0%. Printed by Moravian Printing Works, plant 12, Leninova 21, Olomouc