LT5116B - Process for the preparing electrical conductive coatings on polyethylene surface - Google Patents

Abstract

The present invention relates to a method for modification of polymeric materials which can be used to form an electrical conductive sulfidic coating on them and affording ground for electrochemical metallization. A goal of the invention is to prepare the electrical conductive copper-sulfidic coatings for low density polyethylene by simplifycaing and shortening the process of sulfurization. The goal is reached by using rhombic sulphur solution in carbon disulfide like sulfurization agent, and for preparing of copper sulfides - the interaction of enffused sulphur in polyehtynene with copper salts is carried out. A polyethylene film is sulfurized with 5,7 M sulphur solution in carbon disulfide in very short time at ambient temperature, then is dried with filter paper and treated with 0,4 M solution of copper (I-II) salt together with reductor (hydroquinone).

Description

The present invention relates to the modification of the properties of polymeric materials and can be used to form electrically conductive sulfide coatings thereon, enabling these materials to be used for electroplating as flexible conductors, gas sensors and the like.

A known method of preparing electrically conductive sulfide coatings on polymeric materials is by sulfurizing the surface of the polymeric material with solutions of elemental sulfur in organic solvents (chlorinated hydrocarbons) followed by treatment with a monovalent copper salt solution (see US Patent No. 3682786, TPK B05D 5/12, C23C 3). / 02,1972).

In this way, the desulphurization of polymeric materials is carried out at high temperatures (about 70 ° C) and therefore cannot be used for the desulphurisation of most polymeric substances because of their solubility in organic solvents.

The closest solution to the proposed solution is to obtain electrically conductive sulfide coatings by firstly polymerizing the substances with an acidic sulfuric acid solution with polythionic acid, followed by washing with water and treatment with a copper salt with a reducing agent (hydroquinone) (see Patent No. 4111, TPK B 05 D 5). / 12, C 23 C 3/02, 1997).

In this way, the polymeric materials are sulfurized at high temperature (50-80 ° C) and the required sulfur concentration in the polymer is reached in a relatively short time (1 - = - 2 hours). In addition, the process for obtaining polythionic acids is complex and takes several days.

The object of the present invention is to obtain electrically conductive copper sulfide coatings by simplifying and shortening the sulfurization process of low density polyethylene specimens.

The object is achieved by using a solution of elemental rhombic sulfur in carbon disulphide CS _Z as a sulfurizing agent and by interfering with the sulfur salts in the polyethylene to obtain copper sulphides. The polyethylene film is sulfurized for a very short time with a 5.7 M solution of sirla at room temperature in carbon disulphide CS ₂ , drier with filter paper and exposed to a 0.4 M solution of copper (I-II) salt with a reducing agent (hydroquinone)

EXAMPLE;

Polyethylene film specimens are exposed to a continuously stirred solution of 5.7 M sulfur in carbon disulphide CS _{2 at} 20 ° C for 10 minutes, drained with filter paper, and immersed in a monovalent copper ion solution of a hydroquinone copper salt. Sulfurized specimens are exposed to this solution at 40 4-80 ° C for 1 to 10 minutes and then washed with water for 2 to 4 seconds. The surface impedance of dry polyethylene film specimens with a copper sulphide coating is measured. The surface impedance is 18 * 160 Ω / D. The data are shown in Table 1.

table

Sierra- mo agent Solution molar concentric tation Sulfurization conditions Composition of copper salt solution, g Operation of copper of saline conditions Surface impedance, Ω / D Tem- pera- instant mp, ° C Duration love, min Tempe- ration, ° C Duration love, min 1 2 3 4 5 6th 7th 8th Proposed method Sulfur solution CS ₂ 5.7 20th 10th Copper sulphate crystallohydrate10, hydroquinone -1,0, water 100 80 1 18 + 20 (C ii <( ii ii t < 2 22 4-25 U ii ii ii ii ii 5 84 4-87 (« ii ii α α α 10th 158 4-160

continuation of the table

U ii ii ii ii 60 3 35 4-37 (C c & ii ii ii U 5 48 4-50 << (6 ii ii ii ii 10th 70 4-72 «< U a ii ii 40 6th 65 4-69 u ii a ii ii a 9th 125 4- 127 Analogues h ₂ s ₃₃ o ₆ 0.002 60 60 Copper sulphate crystal hydrate10. hydroquinone1,0, water 100 80 0.5 38 4-44 _ u M 80 30th ii the _ 0.5 35

It can be seen from the table that using an elemental sulfur solution in carbon disulphide for sulfurization of CS ₂ polyethylene specimens and subsequent treatment with a hydroquinone solution of copper salts gives sulfide coatings with lower or slightly higher resistances than the analogue surface. This technique simplifies and shortens the desulphurisation process.

The present invention has the following advantages over the prior art:

- simplifies the process of sulfurization of low density polyethylene specimens by conducting it at room temperature (20 ° C), reducing the surface resistance of the polyethylene film (up to 18-20 Ω / Ο) under appropriate conditions, low temperature sulfur polymerization (10 min) ).

Claims (2)

DEFINITION OF INVENTION CLAIMS 1. A process for preparing electrically conductive copper sulfide coatings wherein the polymeric film is sulfurized and treated with a solution of copper salt, wherein the sulfuric agent is a solution of elemental rhombic sulfur in carbon disulfide. Process for preparing electrically conductive copper sulphide coatings according to claim 1, characterized in that the film is sulfurized with a 5.7 M elemental sulfur solution in carbon disulphide, dewatered on a filter paper and treated with a 0.4 M solution of copper salt with hydroquinone.