KR100358500B1 - Preparation method of electro magnetic wave absorption rtv silicone foaming structure and electro magnetic wave absorption rtv silicone foaming composition - Google Patents

Abstract

The present invention relates to a method for manufacturing a room temperature-curable electromagnetic wave absorbing silicone foam structure of electrical and electronic equipment using a polymer material and a method for manufacturing a room temperature-curable electromagnetic wave absorbing silicone foam composition which can be manufactured at room temperature. It is used to protect electric and electronic devices from malfunctions caused by electromagnetic waves and to block electromagnetic waves generated from the devices so as not to adversely affect the human body and peripheral devices.The polymer composition is poured into a desired form and left at room temperature to provide rigidity of the foam. And foamed and cured to adjust the degree of foaming to form a seamless structure of the desired shape, wherein the polymer composition is 1 to 200 parts by weight of ferrite powder, 1 to 200 with respect to 100 parts by weight of the two organopolysiloxanes Parts by weight, inorganic dielectric powder from 1 to 200 parts by weight, bag It is characterized by consisting of 0.1 to 5 parts by weight of gold catalyst, 5 to 50 parts by weight of silica, and 0.5 to 10 parts by weight of zinc oxide.

Description

FIELD OF THE INVENTION A manufacturing method of a room temperature-curable electromagnetic wave absorbing silicone foam structure and a room temperature-curable electromagnetic wave absorbing silicone foam composition {PREPARATION METHOD OF ELECTRO MAGNETIC WAVE ABSORPTION RTV SILICONE FOAMING STRUCTURE AND ELECTRO MAGNETIC WAVE ABSORPTION RTV SILICONE FOAMING COMPOSITION}

The present invention relates to a method for manufacturing a room temperature-curable electromagnetic wave absorbing silicone foam structure of an electrical and electronic device using a polymer material and a method for producing a room temperature-curable electromagnetic wave absorbing silicone foam composition which can be manufactured at room temperature.

Electric and electronic devices and parts cause malfunctions by electromagnetic waves from outside (EMS: Electro Magnetic Susceptibility) or generate their own electromagnetic waves, which are not only harmful to the human body, but also interact with nearby electric and electromagnetic periods to cause them to malfunction. It can cause fatal damage (EMI: Electro Magnetic Interference). As a countermeasure against the effects of electromagnetic waves, that is, EMS and EMI, a method of shielding electromagnetic waves by wrapping all or part of electrical and electronic devices and components with metal or converting electromagnetic waves generated by using electromagnetic wave absorbers into heat is used. It is becoming.

However, in the case of metal, it is possible to block the passage of electromagnetic waves, but the electromagnetic wave is reflected from the metal surface, causing a problem in other devices. For this reason, electromagnetic wave absorbing materials that dissipate electromagnetic waves are being used for EMS / EMI measures.

As said electromagnetic wave absorbing material, there exist an existing ferrite and the electromagnetic wave absorbing material using the organic polymer material. In particular, the electromagnetic wave absorbing material using the organic polymer material has an advantage of excellent formability and light weight compared to ferrite difficult to process.

The electromagnetic wave absorbing material using the above organic polymer material is manufactured by mixing ferrite powder or dielectric powder or conductive powder such as metal or carbon black with rubber or other polymer material at high temperature and molding by extrusion or press. An example is rubber ferrite.

In the case of the rubber ferrite is excellent in formability compared to the ferrite, but in order to manufacture the desired electromagnetic wave absorbing structure there is a problem that through the cutting and assembly process from a semi-finished product in the form of a plate or tape obtained by extrusion at high temperature.

As an EMS / EMI countermeasure material using a polymer foam, there is a product having a function of shielding electromagnetic waves by forming a metal layer on the surface. The product may be a metal-deposited polymer foam prepared by extruding the polymer at a high temperature, foaming by applying heat, and then vacuum depositing a metal on the surface, or a product in a form of a metal mesh wrapped on the polymer foam.

In addition, in the case of a product such as the metal-deposited polymer foam or the metal mesh coating material, a process of extruding and cutting the polymer material at a high temperature and then applying heat to foam is required, and depositing a metal on the surface of the polymer foam in a vacuum state or Since the metal mesh must be coated, there is a problem that the manufacturing process is cumbersome and the size of the product is limited depending on the deposition equipment.

In addition, the conventional polymer electromagnetic wave absorbing materials are all assembled through a cutting process, there is a problem that it is difficult to manufacture in a seamless form. Electromagnetic wave absorbing materials using polymer materials can also be manufactured by cutting and assembly processes using semi-finished products extruded into plates, so that a seam is generated, and electromagnetic waves leak or penetrate from the seam. .

In order to block the leakage of electromagnetic waves from the seam, a separate process for filling and tightening the seam with a conductive material has to be introduced. Therefore, the assembly process is cumbersome and it is difficult to completely block the leakage of electromagnetic waves from the seam.

The present invention has been made to solve the above-mentioned problems, the method of manufacturing a room temperature-curable electromagnetic wave absorbing silicone foam structure of electrical and electronic equipment using a polymer material and the method of manufacturing a room temperature-curable electromagnetic wave absorbing silicone foam composition which can be manufactured at room temperature It aims to provide.

The method of manufacturing a room temperature-curable electromagnetic wave absorbing silicone foam structure of the present invention is different from the method of cutting and assembling a semi-finished state produced by a conventional extrusion or press. The flowable polymer composition is poured into a mold of a desired form and left to stand at room temperature, and foamed and cured so as to control the rigidity and foaming degree of the foam.

In addition, the room temperature-curable electromagnetic wave absorbing silicone foam composition of the present invention for achieving the above object is an organohydrogen siloxane (Organohydrogen Siloxane) and a hydrosilicate organosiloxane (Hydroxylated Organosiloxane) mixed with a ferrite powder and conductive particles alone or mixed ) And an organopolysiloxane and a platinum catalyst.

1 is a graph showing the electromagnetic wave absorption characteristics of the room temperature-curable electromagnetic wave absorption silicone foam structure of the present invention.

The present invention relates to a method for producing a room temperature-curable electromagnetic wave absorbing silicone foam composition, the composition is 1 to 200 parts by weight of ferrite powder, 1 to 200 parts by weight of conductive particles, 1 to 200 with respect to 100 parts by weight of siloxane By weight, 0.1 to 5 parts by weight of a platinum catalyst for inducing condensation reaction of organosiloxane, 5 to 50 parts by weight of silica and 0.5 to 10 parts by weight of zinc oxide as a foam reinforcement agent. Then, the additives are mixed in a roll 3 or a mixer to prepare a composition, and the composition is poured into a mold of a desired form and left at room temperature, and foamed and cured so as to control the rigidity and foaming degree of the foam. Manufacture.

In the present invention, the hydrosylate organosiloxane and the organohydrogensiloxane, which are capable of forming a foam by releasing gas by condensation reaction at room temperature, are used.

5 to 50 parts by weight of silica was added as a reinforcing material for the foam. If the added amount is 5 parts by weight or less, there is no reinforcing effect of silica on the silicone foam, and thus the foam is not rigid. At 50 parts by weight or more, the foaming degree of the foam is lowered, and the rigidity of the foam is also lowered.

Zinc oxide was added from 0.5 to 10 parts by weight as an auxiliary reinforcing agent and a cocatalyst of the foam. If the added amount was 0.5 parts by weight or less, the effect as a catalyst was not effective, and at 10 parts by weight or more, the foaming degree of the foam was reduced.

In order to impart the electromagnetic wave absorbing function to the foam, as ferrite, 1 to 200 parts by weight of manganese zinc (Mn-Zn) -ferrite, nickel zinc (Ni-Zn) -ferrite, and kappa zinc (Cu-Zn) -ferrite alone or in combination Used. Less than 1 part by weight of the electromagnetic wave absorption function was insignificant, and more than 200 parts by weight it was difficult to maintain the rigidity of the foam structure. When the ferrite powder is added, the electromagnetic wave absorption function is realized by the magnetic loss. The ferrite powder is mainly effective in the frequency band of 1 kHz or more. As the ferrite content increased, the resonant frequency shifted to the low frequency band, and as the degree of foaming increased, the resonant frequency moved to the high frequency band. By controlling the foaming degree and the content of ferrite, it is possible to adjust the frequency band in which electromagnetic wave absorption is particularly effective between 1 kHz and 100 kHz. As an example, when 50 parts by weight of ferrite was added and foamed at a volume ratio of 10%, electromagnetic wave absorption characteristics of 90% or more were realized in the 1.2 GHz band.

As the conductive particles, 200 parts by weight of carbon black and graphite, metal powder and metal fiber, and polymer powder 1 coated with a metal conductive film were used alone or in combination. The electromagnetic wave absorption function could not be expected at 1 part by weight or less, and it was difficult to maintain the rigidity of the foam structure at 200 parts by weight or more. In the case of adding carbon black, an effective electromagnetic wave absorption function was realized mainly in the frequency band of several tens of MHz to 100 Hz. For example, when 30 parts by weight of carbon black was added, the electromagnetic wave absorption characteristics of 90% or more were exhibited at 40 Hz. In addition, when 1 to 200 parts by weight of inorganic strontium oxide-based inorganic dielectric powder was mixed, effective electromagnetic wave absorption characteristics were exhibited in the high frequency band of 1 GHz or more.

When conductive particles or dielectric powder are added, the electromagnetic wave absorption function can be realized by dielectric loss, and when mixed with ferrite, the electromagnetic wave absorption function can be realized by two kinds of magnetic loss and dielectric loss. An electromagnetic wave absorber having an electromagnetic wave absorbing function in a wide frequency band can be produced.

EXAMPLE

The present invention will be described in detail with reference to Examples.

The composition of the Example about the manufacturing method of the room temperature hardening type electromagnetic wave absorption silicone foam composition of this invention was put together in Table 1.

Compound Example One 2 3 4 5 6 7 Polymer # 1 100 100 100 100 100 100 100 Polymer # 2 11 9.6 10.5 14.5 14.5 105 11 Platinum Catalyst (ppm) 25 25 25 25 25 25 25 Silica - 35 20 - - 20 30 Manganese Zinc Ferrite 150 150 160 100 - 150 - Kappa zinc ferrite - - - - 170 - 130 Carbon black - - 15 50 - - 35

In Table 1, polymer # 1 is hydroxy methyl tertiary hydroxymethyl and dimethylsiloxane polymer having a viscosity of 5000 cP at room temperature, and polymer # 2 is trimethylsiloxy endblock having 3. 2 parts by weight of hydrogen. Polymethylhydrogen siloxane, and silica used podsilica surface-treated with trimethylsiloxane groups having a specific surface area of about 200 m 2 / g. Manganese zinc or gapa zinc ferrite was used to impart electromagnetic shielding performance, and carbon black was also used.

The room temperature-curable foams prepared as in the embodiments of the present invention were able to adjust the effective band and degree of electromagnetic shielding according to the conductivity of carbon black or the permeability of ferrite.

In addition, as shown in Fig. 1, the embodiment of the present invention exhibits an electromagnetic wave absorption characteristic of about 8 GHz in the vicinity of the 40 GHz band according to the composition, and in the case of Example 4 in the band of 60 GHz. Electromagnetic wave absorption characteristics of 12 GHz or more are shown.

Since the room temperature-curable electromagnetic wave absorbing silicone foam structure prepared as an embodiment of the present invention is poured into a mold of a desired form and left at room temperature to foam and harden to be formed into an electromagnetic wave absorbing room temperature-curable foam having elasticity. The manufacturing method is simpler than a structure using a conventional polymer electromagnetic wave absorbing material that needs to be cut and assembled.

In addition, since it is not necessary to apply heat or high frequency in the process of foaming and curing, it is possible to significantly reduce the amount of energy consumed in the manufacture of the product, and thus it is possible to produce an environment-friendly product in terms of energy saving.

In addition, since the three-dimensional shape can be manufactured according to the shape of the mold used for molding, molding can be performed in a seamless structure and there is no electromagnetic leakage to the joint.

It is also possible to cut and assemble the plate in semi-finished form. In this case, if the joint is filled with a fluid composition, foaming and curing at room temperature can easily block leakage of electromagnetic waves from the joint.

The room temperature-curable electromagnetic wave absorbing silicone foam structure according to the present invention has elasticity and has a high flame retardant effect by ferrite. In addition to the role of electromagnetic wave absorption, it also has the function of impact reinforcement and flame retardant reinforcement of electrical and electronic products.

As described above, the method for manufacturing a room temperature-curable electromagnetic wave absorbing silicone foam structure according to the present invention has not only equivalent or equivalent electromagnetic wave absorbing effect as compared with the conventional electromagnetic wave absorbing material, but also the manufacturing process is simple, due to the seam Because there is no leakage of electromagnetic waves. Its excellent electromagnetic shielding function protects the human body, prevents fatal damage and malfunction of the device, and also has the effect of protecting against shock and flame retardant.

Claims (9)

1 to 200 parts by weight of ferrite powder, 1 to 200 parts by weight of inorganic particles, 1 to 200 parts by weight of inorganic dielectric powder, 0.01 to 5 parts by weight of platinum catalyst, based on 100 parts by weight of two organopolysiloxanes, A polymer composition composed of 5 to 50 parts by weight of silica and 0.5 to 10 parts by weight of zinc oxide is poured into a mold of a desired form, left to stand at room temperature, and foamed and cured to control the rigidity and foaming degree of the foam. A method for manufacturing a room temperature-curable electromagnetic wave absorbing silicone foam structure, characterized in that to produce a structure of the form. delete The method of claim 1. The polymer composition releases gas by condensation reaction at room temperature and forms two or more hydrides in one molecule with respect to 100 parts by weight of the organopolysiloxane having a hydroxyl group capable of reacting with 100 parts by weight of two kinds of organopolysiloxane capable of forming a foam. A method for producing a room temperature-curable electromagnetic wave absorbing silicone foam structure, comprising 50 parts by weight of organopolysiloxane 1 containing a lozenge. The method of claim 1. The method for producing a room temperature-curable electromagnetic wave absorbing silicone foam structure, characterized in that 1 to 200 parts by weight of manganese zinc-ferrite, nickel zinc-ferrite, and kappa zinc-ferrite alone or in combination as the polymer composition. The method of claim 1. Conductive carbon black, graphite, metal powder, metal fiber, metal coated polymer particles in the polymer composition. Method for producing a room temperature-curable electromagnetic wave absorbing silicone foam structure, characterized in that the inorganic dielectric powder alone or in combination used 1 to 200 parts by weight. In the room temperature-curable foaming composition having a function of absorbing electromagnetic waves, 1 to 200 parts by weight of ferrite powder, 1 to 200 parts by weight of conductive particles, and 1 to 200 parts by weight of inorganic dielectric powder, based on 100 parts by weight of two kinds of organopolysiloxanes. And a room temperature curing electromagnetic wave absorbing silicone foam composition comprising 0.01 to 5 parts by weight of a platinum catalyst, 5 to 50 parts by weight of silica, and 0.5 to 10 parts by weight of zinc oxide. The method of claim 6. The composition is two or more hydrogen in one molecule with respect to 100 parts by weight of the organopolysiloxane having a hydroxyl group capable of reacting at 100 parts by weight of two kinds of organopolysiloxane capable of forming a foam by releasing gas by condensation reaction at room temperature Organopolysiloxane containing 1 to 50 parts by weight of the room temperature-curable electromagnetic wave absorbing silicone foam composition. The method of claim 6. A room temperature-curable electromagnetic wave absorbing silicone foam composition, characterized in that 1 to 200 parts by weight of manganese zinc-ferrite, nickel zinc-ferrite, and kappa zinc-ferrite alone or in combination as ferrite in the composition. The method of claim 6. Conductive carbon black, graphite, metal powder, metal fiber, metal coated polymer particles in the composition. Room temperature-curable electromagnetic wave absorbing silicone foam composition, characterized in that the inorganic dielectric powder alone or in combination used 1 to 200 parts by weight.