JPS60113996A - Electromagnetic shielding reinforced plastic material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fiber 4111 reinforced plastic composite fiber which has excellent electromagnetic wave shielding ability, high strength and good moldability.

In recent years, with the spread of various electronic devices, the problem of electromagnetic interference has come into focus. At the same time, plastic housing materials, which have been widely used due to their ease of mass production and moldability, are being reconsidered due to their lack of electromagnetic wave shielding performance. As a result, it has become indispensable to provide plastic with TL electromagnetic wave shielding performance by imparting conductivity to the plastic Ujingui 4 to reflect or absorb unnecessary radio waves. There are two ways to improve the shielding performance of radio waves by imparting 1+5 electrical properties to plastics: One method is to form a conductive film layer on the surface of the plastic by applying a conductive paint, thermal spraying, plating, or vapor deposition of metal on the surface of the plastic. The method of sandwiching a metal i-plate between two plastic plates falls into this category. Another method is to use conductive plastic made by kneading metal powder, metal flakes, short metal fibers, carbon powder, carbon fibers, etc. with resin. Conductive plastics, which are polymer resins themselves that have been given conductivity, also fall into this category.

By the way, the former method of forming a conductive film layer on the surface of plastic is an effective method for improving electromagnetic wave shielding performance. However, it is very time-consuming and expensive, and the conductive film layer deteriorates during use, resulting in peeling and cracking, which can lead to problems during use. have. In addition, the method of sandwiching a thin metal plate between two plastic sheets has the disadvantage that it is more difficult to process the metal sheet during the process of forming it into a housing than a flat plate. On the other hand, the latter method of imparting conductivity to plastics is excellent in mass production and moldability, but has the disadvantage of poor electromagnetic wave shielding performance. In order to compensate for this drawback, if the filling amount of metal or carbon is increased, for example, the volume mixing ratio must be at least 13%. However, it has the disadvantage that processability, strength properties, colorability, etc. are significantly impaired.

In view of the above-mentioned disadvantages, the present invention aims to provide a side slope that has extremely high electromagnetic wave shielding performance, and at the same time has sufficient strength and excellent moldability.

Now, FRP generally uses long glass fibers as its reinforcement side.
1 or the most used. The reason why long glass fibers are used is that they have high strength and can be heated up to 300°C.
This is because it has excellent properties such as being extremely thermally stable, durable, and not absorbing water. Furthermore, long glass fibers can be easily used in shapes suitable for various plastic molding methods, such as chopped strands, chopped strand mats, continuous strand mats, cloths, or rovings. .

The present inventors have discovered that a sufficiently high electromagnetic wave shielding performance can be achieved by mixing metal-footed glass fibers whose surfaces are coated with metal into plastic, and have thus arrived at the present invention.

That is, the present invention provides electromagnetic shielding glass ξL1 with glass fiber as the reinforcing side; fiber reinforced plastic 44 material,
Metal-coated crow fibers 1 to 3 to IIO with heavy bo%
%, and the uncoated glass fiber is 15 to 60%, but the total amount of both fibers is 70% or less, and is a reinforced plastic material for gJM shielding.

The reinforced plastic side slope for electromagnetic shielding of the present invention has excellent electromagnetic shielding performance, high mechanical strength, and excellent moldability.

The reinforced plastic side slope of the present invention is! Contains -40 M% by weight of metal-coated glass fibers and 1 to 60% by weight of uncoated glass fibers. In order to provide this side slope with electromagnetic shielding performance, it is necessary to contain 5% or more, preferably 7% or more of metal-coated glass fiber.

In addition, in order to provide this side slope with a sufficient mechanical angle of 41 degrees, it is necessary to contain not less than /S weight % of uncoated glass fiber. The tensile strength of metal-coated glass fibers is as low as 1 to 70% of the tensile strength of uncoated long glass fibers. In addition, the contact between the metal covering 8'i glass fiber and the resin.
Since the reinforcing effect of gold-14 coated glass fiber is low compared to that of uncoated glass fiber, the strength effect of uncoated glass fiber is lower, and the reinforcement effect of metal coated glass fiber is lower than that of uncoated glass fiber.
It has magnetic V and shielding ability.Gold Ff4 fractured glass fiber containing h↓ and non-similar glass fiber containing tI
If 4 is too large, the molding process will be worse, so iiJ should not exceed /lo%, and the latter should not exceed O%.
70% of the total of 31%
It is necessary not to exceed.

In addition, if the ratio of the former to 1'ffl is too large, the mechanical strength of the side slope will decrease, so the ratio of the lever is 50
It is preferable not to exceed %.

The outer diameter of the gold FJ4 coated glass fiber used in the present invention is preferably /3-110 microns; if the thickness of the metal coated M layer is too small, the electromagnetic shielding effect will be small, and if the thickness is too large, the electromagnetic shielding effect will be small. A thickness of 5 to 1.5 microns is preferred since the fibers may be undesirably cut during the operation. Further, the longer the length of the metal-coated glass fiber, the more excellent the electromagnetic shielding effect can be obtained. If the length is less than somm, the electromagnetic shielding effect will be reduced, so it is preferably 100 mm or more, and more preferably more than somm. When this length differs depending on the individual fibers, the length and weight of each fiber are expressed as el.
and Wl(Σ11W1)/(Σw1 edge value) to define the average length.

Uncoated glass used in the present invention g! ; All
As usual FRPfFPf lath fiber can be used, with a diameter of 3 to 30 microns and /S to /00 m
A length of m or more is used.

Various methods and apparatuses for producing metal-coated glass fibers have been proposed and are already known. A typical method is to draw out the glass melted in the bot through a nozzle hole provided at the bottom and draw it out.

During this process, molten metal (for example, aluminum) is eluted from small holes in an inert gas atmosphere, and the tip of the molten metal is brought into contact with a stretched glass fiber and wound onto a drum. Various metal coatings on the glass fiber surface can be obtained depending on the manner in which the glass fiber contacts with the molten metal.

Figures 1 and 2 are cross-sectional views of metal-coated glass fibers, and show how metal is coated. Covered with 12. Figure 2 shows crow braid/3
The figure shows a case where about ゛V of the outer periphery is coated with metal/lI, and both can be used in the present invention. Furthermore, it is preferable that the metal to be coated has a melting point approximately 100° C. to 200° C. lower than the softening point of the glass and a high electrical conductivity. In order to bond glass and metal, it is necessary to heat the glass, for reasons that are not well understood. This is because even if low-temperature glass is brought into contact with molten metal, the glass and metal will not bond.

On the other hand, because the glass fibers are drawn, the temperature of the glass fibers is earth-like, and even if they are softened and deformed, it will be uncomfortable, so a metal having a melting point 100 to 200° C. lower than the softening point of glass is preferable. Electromagnetic tours also teach us that materials with high electrical conductivity have good shielding performance against electromagnetic waves. Therefore, the metal of the metal-coated glass fiber is preferably aluminum or an aluminum alloy containing more than SO weight of aluminum.

Examples are shown below.

The electromagnetic wave shielding performance (SE value) is the intensity of the electromagnetic wave incident on El, and the intensity of the electromagnetic wave that passes through EO and exits.

1 Measurement of SE-20Log10-EO 3F value is carried out by Kansai Eco Industrial Promotion Center (KEC).
) according to the measurement method. This method is highly regarded in the industry. Also, the SE value changes depending on electric field waves and magnetic field waves, but magnetic field waves generally have a higher S than electric field waves.
E value becomes low. Therefore, an example of measurement of magnetic field waves is shown here.

It is said that if the SE value is LO dB or more, it can be put to practical use, and this serves as a rough guideline.

Thermal Ef plastic resin reinforced plastic association using glass long fibers and aluminum coated long glass fibers as reinforcement: A to 3. It was molded into a plate with a thickness of gmm. At this time, continuous strand mano (・(
Using the aluminum corrugated crow braid, the outer diameter of the braid is 30tt, the inner diameter (glass diameter) is 10μ, and the long pieces are intersected in a continuous manner to create a divinely thick continuous strand of 1゜ mat (the second mat). A matte material was prepared. A first mantle and a second mantle were laminated and interposed between two sheets of thermal 1'+7 plastic j'jJ llFr (polypropylene) plates, and a reinforced composite fiber was obtained by heating and pressurizing. The combined weight of the first mat and the second mat in the reinforced composite case Δ was kept constant, and the mixing ratio of the long glass fibers and the aluminum-coated glass fibers was varied by selecting the thickness of each mantle. Figure 3 shows the frequency 3'OM H
These are the results of measuring the shielding performance of various composite materials with respect to magnetic field waves over a Z width of 1001000. In this case, the glass fiber reinforcement (including metal-coated glass fibers) was incorporated to account for approximately 0% of the amount of composite phase metal. Some of the 100 glass fiber reinforcement materials will be replaced with aluminum-coated fibers. In Fig./, the aluminum coat contamination and the glass long fiber contamination weight are respectively 3% and 37% for sample/2, 1g% and 22% for sample 3, and 1g% and 22% for sample/3, based on the total weight of the composite material. is 2S
% and 75% floor S indicate the frequency dependence of shielding performance at /IO% and 0%.

In addition, in Fig. 3, a is a short aluminum string (length 3 to 110n1)
．． 39gm containing 20% by volume of 30μ average diameter)
mH polypropylene plate, b is 1 when aluminum powder with the same diameter SOμ is mixed in volume ratio: 1O%,
3. This is the shielding performance of a polypropylene plate with a thickness of 2 mm. It can be seen from FIG. 3 that the reinforced plastic plate sample 2 of the present invention containing aluminum-coated long glass fibers has excellent shielding performance.

The table also shows the bending strength of the molded plate measured by three-point bending.

It can be seen that as the mixing ratio of aluminum-coated fibers increases, the bending strength decreases.

From FIG. 3 and the table, it can be seen that Samples 2 to 4' of the present invention have high electromagnetic shielding performance and high mechanical strength.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing metal-coated glass fibers used in the present invention, and FIG. 3 is a graph showing the electromagnetic shielding performance of the present invention. Figure 1 Figure 2

Claims (3)

[Claims] (1) In glass fiber-reinforced plastic material for electromagnetic shielding using glass fiber as reinforcement, the amount of metal-coated glass fiber is 5 to 110%, and the uncoated glass fiber is 75 to 30%, but both The total amount of fiber is less than 70%,
Reinforced plastic material for electromagnetic shielding, each characterized by gold stone. (2) The reinforced plastic material for electromagnetic shielding according to claim 1, which contains the metal-coated glass fiber in an amount not exceeding 50% by weight based on the total amount of the metal-coated glass fiber and the non-intoxicated glass fiber. (3) The metal-coated glass fiber is at least ioo
The reinforced plastic side slope for electromagnetic shielding according to claim 1 or claim 1, having an average length of mm. (411) Reinforced plastic material for electromagnetic shielding according to claims 1 to 3, wherein the metal of the metal-coated glass fiber is aluminum or an aluminum alloy containing aluminum in an SO weight percent or more