RU2410298C1 - Electroconductive adhesive tape - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: electroconductive adhesive tape used to join foam pads of screen vacuum heat insulation of spacecraft consists of a polymeric tape base, an adhesive layer and a working layer. The working layer consists of a strip of metal or an alloy of a metal such as silver, aluminium, zinc, copper and steel at the centre of the tape and a strip of adhesive or permanent adhesive on the edges. The material of the base of the adhesive tape is selected from radiation resistant substances such as polyimide, polyethylene terephthalate, polyamide or mixtures thereof.

EFFECT: high reliability of the joint between the tape and the surface of heat insulation foam pads and electroconductivity at the centre of the adhesive tape.

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Description

The invention relates to layered materials made of layers with different physical properties, namely, materials based on a metallized polymer film that can be used in the field of space technology, in particular to the field of protection of spacecraft.

Various thermal insulation coatings are used for thermal protection of spacecraft (SC). Currently, the most effective thermal insulation materials are mats of screen-vacuum thermal insulation (EVTI). In addition to thermal protection, spacecraft also need electrostatic protection, since the flow of charged particles from the sun creates an electrostatic charge on the surface of the spacecraft. At the same time, a much smaller charge is created on the shaded side. Since the EVTI consists of separate mats (parts), on separate EVTI mats located on the side of the Sun and in the shadow, the charge is much different, which can lead to electrical breakdowns and interference with the operation of the spacecraft electronic equipment. To equalize the electrostatic potential and charge removal to the spacecraft body, separate EVTI mats are connected with an electrically conductive adhesive tape. The components of adhesive tape for joining EVTI mats are selected from substances that are resistant to radiation. On top of the adhesive tape can be applied an antistatic composition or a combined external coating described in application RU 2008125256.

Known metallized tape with an adhesive layer (patent RU 2015924) for waterproofing of ground aluminized heat-insulating structures, consisting of aluminum foil and an adhesive layer based on polyurethane ureylene and perchlorovinyl resin. Its disadvantages are very poor conductivity of the adhesive layer, which is actually an insulator, and low strength.

Adhesive tapes are known with an electrically conductive adhesive layer consisting of a conductive polymer and adhesive (WO 2007055511, WO 2006057465). Their main disadvantage is the low conductivity of the adhesive layer.

Adhesive tapes with an electrically conductive layer of a mixture of an ionic polymer and an ionic salt of an alkali or alkaline earth metal are known (WO 1998010029, WO 1996020983, WO 1995030720). Their main disadvantage is the low conductivity of the adhesive layer.

Conductive tapes are known with an adhesive layer mixed with electrically conductive soot particles (Adhaesion-Kleben & Dichten, 2007, 51 (7-8), 34, 36-39). The main disadvantage of these tapes is the very low electrical conductivity of the mixture of adhesive with soot.

Conductive tapes are known with an adhesive layer mixed with electrically conductive graphitized carbon fibers (JP JP 2008186590). The main disadvantage of these tapes is the low electrical conductivity of the mixture of adhesive with carbon fiber.

Conductive tapes are known with an adhesive layer mixed with electrically conductive particles of carbon nanoscale material (application US 20080241507). The main disadvantage of these tapes is the low electrical conductivity of the adhesive-carbon mixture.

Conductive tapes are known with an adhesive layer mixed with electrically conductive particles of carbon nanotubes (application US 20080245548). The main disadvantage of these tapes is the low electrical conductivity of the adhesive-carbon mixture.

Conductive tapes are known with an adhesive layer mixed with electrically conductive particles of metal oxides (patent KR 7751125). The main disadvantages of these tapes are the low electrical conductivity of the mixture of adhesive with an electrical conductor and the deterioration of adhesion when a non-adhesive component (metal oxide) is added to the adhesive.

Conductive tapes are known with an adhesive layer mixed with electrically conductive particles of metal powders (in application JP 2008081652 aluminum, in patent WO 2008023452 an alloy of tin and bismuth, in patent EP 0134623 silver, in Adhaesion-Kleben & Dichten, 2007, 51 (7-8) ), 34, 36-39 copper powder and aluminum shavings). The main disadvantage of these tapes is the deterioration of adhesion when a non-adhesive component (conductor) is added to the adhesive, as well as the fact that this tape is designed to bind hard substrates (patent WO 2008023452).

Conductive tapes are known with an adhesive layer mixed with electrically conductive entangled fibers of metal or metal coated non-conductive fibers laminated to a metal foil (patent WO 1995007600). The disadvantages of these tapes are deterioration of adhesion when a non-adhesive component (conductor) is added to the adhesive, as well as low strength (the tape is intended only for shielding from electromagnetic radiation).

Conductive tapes are known with an adhesive layer mixed with electrically conductive glass beads coated with a metal layer (patent EP 0330452). The disadvantages of these tapes are the deterioration of adhesion when a non-adhesive component (conductor) is added to the adhesive, the high cost of the constituent components and the complexity of manufacture.

Conductive tapes are known with an adhesive layer mixed with electrically conductive particles with a ferromagnetic core (patent EP 0174777). The disadvantages of these tapes are the deterioration of adhesion when a non-adhesive component (conductor) is added to the adhesive, the high cost of the conductive coating (silver) and the complexity of manufacture.

The closest in technical essence to the present invention is a conductive adhesive tape (patent EP 1020505), consisting of regions anisotropically conducting along the thickness of the tape, the gaps between which are filled with adhesive with a possible intermediate electrically conductive layer between the base and the layer of conductivity and adhesion regions. The tape is made by printing conductive regions and filling the space between them with adhesive, or by applying adhesive and compressing the conductive regions into it, and then laminating with a conductive film. The disadvantages of this material are reduced adhesive properties and rapid degradation of the conductivity characteristics over time, as well as a very complex manufacturing technology. The prototype does not show the shelf life of the adhesive tape. According to data for a similar Russian material, Kontakol K-13 glue TU TCAF.670094.015 (NII GIRIKOND OJSC), consisting of 80% silver particles and 20% adhesive, has a pot life of 0.5 years in an atmosphere of the earth that is less aggressive than the conditions in the Earth’s orbit, where oxygen is present in the atomic state and the temperature of the upper skin layer from the side of the Sun reaches 150 ° C.

The aim of the present invention is to eliminate these drawbacks and increase the reliability of the connection of the adhesive tape with the surface of the EVTI mats at the edges of the adhesive tape and the electrical conductivity in the Central part of the adhesive tape in contact with the joints of the EVTI mats.

This result is achieved by the fact that the working layer of adhesive tape is divided into three strips: in the center is a strip of metal (mainly aluminum, although other metals and alloys can be used, for example, zinc, copper, silver, steel) with very low adhesion and maximum electrical conductivity, and on the edges of the adhesive tape are adhesive strips with very low electrical conductivity and the highest possible stickiness, which ensures reliable connection with the surface in open space. The metal tape is glued to the base film with a layer of glue, including permanent adhesive, or adhesive, the same as in the working layer or different from it. The base film consists of a polymer - polyethylene terephthalate, polyimide, polyamide or a polymer of another class. The tape materials are selected from radiation resistant materials. The width of the stripes may be the same or different.

Example 1

An adhesive layer is applied to a polyethylene terephthalate base film 40 mm wide and after drying the solvent, a silver tape 20 mm wide and 0.01 mm thick is rolled in the center of the film. An adhesive tape is obtained with the following characteristics: peeling force on the adhesive strip 6.1 N / cm, resistance on the metal strip 0.005 Ohm / □. The warranty shelf life in outer space is at least 10 years.

Example 2

An adhesive layer is applied to a polyethylene terephthalate base film 40 mm wide and after drying the solvent, an aluminum tape 20 mm wide and 0.01 mm thick is rolled in the center of the film. An adhesive tape is obtained with the characteristics: peeling force on the adhesive strip 6.0 N / cm, resistance on the metal strip 0.01 Ohm / □. The warranty shelf life in outer space is at least 10 years.

Example 3

An adhesive layer is applied onto a polyethylene terephthalate base film 40 mm wide and after drying the solvent, a zinc tape 20 mm wide and 0.01 mm thick is rolled in the center of the film. An adhesive tape with the characteristics is obtained: peeling force on the adhesive strip of 6.2 N / cm, resistance on the metal strip of 0.023 Ohm / □. The warranty shelf life in outer space is at least 10 years.

Example 4

An adhesive layer is applied to a 40 mm wide base film and after drying the solvent, a copper tape 20 mm wide and 0.01 mm thick is rolled in the center of the film. An adhesive tape is obtained with the following characteristics: tear-off force on the adhesive strip 6.0 N / cm, resistance on the metal strip 0.007 Ohm / □. The warranty shelf life in outer space is at least 10 years.

Example 5

An adhesive layer is applied to a 40 mm wide base film and after drying the solvent, a steel tape 20 mm wide and 0.01 mm thick is rolled in the center of the film. An adhesive tape is obtained with the characteristics: peeling force on the adhesive strip 6.0N / cm, resistance on the metal strip 0.06 Ohm / □. The warranty shelf life in outer space is at least 10 years.

Example 6

An adhesive layer is applied to a 40 mm wide polyamide base film and, after drying the solvent, a steel tape 20 mm wide and 0.01 mm thick is rolled in the center of the film. An adhesive tape is obtained with the characteristics: peeling force on the adhesive strip 6.1 N / cm, resistance on the metal strip 0.06 Ohm / □. The warranty shelf life in outer space is at least 5 years.

Brief Description of the Drawings

Figure 1. Cross section of adhesive tape.

1 - polymer film;

2 - a layer of glue;

3 - a layer of adhesive or glue;

4 - metal layer.

Figure 2. View of the adhesive tape from the side of the work surface.

a) a strip of adhesive or glue;

b) is a strip of metal.

Claims (1)

An electrically conductive adhesive tape used to connect mats of screen-vacuum thermal insulation of a spacecraft, consisting of a base polymer tape, a layer of glue and a working layer, characterized in that the working layer in the center of the tape consists of a strip of metal or alloy, such as silver, aluminum , zinc, copper, steel, and at the edges from adhesive or permanent adhesive strips, the adhesive tape base materials being selected from radiation resistant materials such as polyimide, polyethylene terephthalate, polyamide and mixtures thereof.