FI122320B - Electromagnetic radiation reflective and / or limiting product - Google Patents

Description

Product reflecting and / or limiting electromagnetic radiation

The present invention relates to an electromagnetic radiation reflecting and / or limiting product comprising an electrically conductive fabric having a fiber backing layer and an electrically conductive layer of carbon particles or other electrically conductive particles having nano or submicron size carbon conductive or similar particles admixed with the matrix resin, the mixture being impregnated around the backing fibers and cured to an electrically conductive layer prior to use of the fabric in the application product.

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US-2004/0188890 A discloses an electromagnetic interference protection material comprising an electrically conductive fabric in a polymer matrix. The fabric is pretreated with an impregnating resin containing electromagnetic particles such as metal particles. The particle length ranges from "equal to unprotected electromagnetic wavelength - half wavelength". The fabric may be fiberglass. The electromagnetically active element has a non-woven structure, which is difficult to adhere to the hard resin body of the product.

US-2005/0025967 A describes a fiberglass fabric which is coated with a poly-20 matrix matrix mixed with electrically conductive particles having a size ranging from 10 nm to 10 µm. The coated fabric is suitable for eg. for electromagnetic interference applications. The function of the particles is to reduce the mutual adhesion of the fibers so that the fibers can be treated with "air jet fabrics". In typical circuit applications, the particles have a high electrical resistance.

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JP-01158799 A discloses an electromagnetic interference protection material consisting of a plastic layer and a mesh-like fabric. The fabric is impregnated with a resin mixed with electrically conductive metal powder prior to use in the manufacture of the protective material. The plastic layer is a transparent plastic film x 30 laminated together with a mesh-like fabric, resulting in a flexible protective sheet.

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g US-5,077,556 A discloses an electromagnetic radiation protective material comprising layers of plastic and a support fabric impregnated with a resin mixed with a carbon pigment or a magnetic pigment. The product is particularly suited for military use as a protective cover to prevent the subject from being seen by thermal imaging or radar.

DE-3 421 196 A discloses a radomaterial comprising a plastic matrix and a fabric reinforcement consisting wholly or partly of hollow fibers.

The electrically conductive fabrics with carbon particles have been made especially as heating elements for floor and ceiling heating. They use carbon particles in a composite matrix matrix resin. Such an electrically conductive fabric is suitable for heating purposes but is poorly suited for use as a component component of plastic products that reflect and / or limit electromagnetic radiation. Due to their heating purpose, their electrical conductivity is rather poor. In addition, electrically conductive particles are readily released from known conductive mats into the resin of the plastics product to be manufactured, which reduces the radiation-reflecting and / or limiting effect of the plastics product; especially in the antenna tuning application.

It is an object of the invention to provide an antenna radio whose radiation reflecting and / or limiting layer can be manufactured separately with the desired electromagnetic properties and firmly attached to the antenna radio as an integral part of its body.

This object is achieved by the invention on the basis of the features set forth in claim 1.

Using nano- and submicron-sized carbon particles that are well mixed with the correct amounts of matrix resin and impregnated around the backing fibers and cured to form an electrically conductive layer prior to use of the fabric in the application product provides the application product with a precise, highly conductive layer no loose conductive particles in application product resin, x 30 en

When the plastic or resin of the antenna radio frame penetrates through openings or holes in the electrically conductive tn $ 2 fabric, the fabric does not weaken the structure, but rather strengthens it and adheres firmly to the frame as its integral part,

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The following figure illustrates one embodiment of the invention wherein the electrically conductive fabric is a fabric with cross-linked fibers 1 and is surrounded by an electrically conductive layer 2 produced by impregnating the fabric into a mixture of matrix resin and carbon particles. Impregnation may be by dipping the tissue into the mixture or injecting the mixture into the tissue. It is essential that the carbon particles are nano- or submicron-sized, or the like very small particles, whereby a good electrical conductivity is achieved with a relatively thin conductive layer 2. The invention is not limited to nano- or submicron-sized particles, but other size particles can be used.

10 The electrically conductive layer matrix resin is one of the following: vinyl ester, polyester, epoxy, melamine, phenol, urethane. All other similar resins may also be suitable which are compatible with the process resin used in the subsequent application product preparation. The fibers of the electrically conductive fabric may be fiberglass and / or carbon fiber and / or natural fibers such as cotton. The fabric may be woven or knitted. The fabric is a fabric whose fibers are surrounded by a conductive layer 2 such that the mesh of the fabric forms open apertures or holes. The fabric can then be placed inside the antenna radiator body so that the plastic or resin of the body has penetrated through openings or holes in the fabric to improve adhesion. Improvement of adhesion to the process matrix has also been improved by chemically bonding the carbon particles to the matrix or treating the electrically conductive fabric prior to processing to improve adhesion.

In the electrically conductive fabric according to the invention, the conductive layer 2 surrounding the fibers forms thin tubes which form a mesh structure corresponding to the passage of the fibers 1, δ

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g When the conductive fabric 3 is used in electromagnetic radiation in reflective and / or limiting antenna radios 4, the antenna radi contains an electrically conductive x 30 fabric 3 as an integral part of product 4, the carbon particles confined to their own · matrix resin, electrical

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$ 2 conductive particles could get into the antenna radio array, they could cause there

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g interference. The antenna radio 4 may be manufactured, for example, by the pultrusion process, or any composite article manufacturing process or thermoplastic method 35 using an electrically conductive fabric 3 as a reinforcing layer which is fed to the other reinforcements 4 prior to the heated pultrusion mold or extrusion.

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Claims (4)

1. Electromagnetic radiation reflective and / or limiting product having an electrically conductive fabric having a support layer formed by fibers (1) and one of 5 carbon particles or other electrically conductive particles formed electrically conductive layer (2) with nano- or submicron-sized carbon particles , or corresponding other electrically conductive fine particles mixed in a matrix resin, which mixture is impregnated around the support layer fibers (1) and cured to an electrically conductive layer (2) prior to the use of the fabric (3) in the application product, characterized in that: the product (4) is an antenna radome, and the fabric is a fabric whose fibers (1) are surrounded by the conductive layer (2) such that the mesh (3) meshes form open openings or heels, and that the electrically conductive the fabric (3) is arranged inside the body of the antenna radome (4) as its integral part, such that the plastic or resin (5) of the body has penetrated through the openings or heels of the fabric (3). 15 Product according to claim 1, characterized in that the matrix resin is one of the following: vinyl ester, polyester, epoxy, phenol, melamine, urethane, polyurethane or other binder resin. 3. Product according to claim 1 or 2, characterized in that the fibers of the support layer are glass fibers and / or carbon fibers and / or natural fibers such as cotton. Product according to any one of claims 1-3, characterized in that the mixture of the fibers of the electrically conductive fabric (1) surrounding the carbon particles and the matrix resin form thin tubes which form a web-shaped structure corresponding to the course of the fibers (1). δ cv 03 o o oo X cc 0- LO 00 δ CD o o cv