JP4657644B2 - Method for manufacturing electromagnetic wave shielding sealant - Google Patents

Description

The present invention relates to a method for producing a sealing material used for construction or civil engineering. More specifically, electrically and structurally cut portions such as gaps between metal window frames and conductive glass windows used in structures that shield electromagnetic waves and joints between metal panels are electrically and structurally cut. The present invention relates to a method for manufacturing an electromagnetic wave shielding sealing material for connection.

Conventionally, as this type of electromagnetic wave shielding sealant, a conductive sealant composition comprising, as a main component, at least one of a modified polysulfide polymer and its curing catalyst, or a modified silicone polymer and its curing catalyst, and containing carbon fiber therein. (For example, refer to Patent Document 1).
In the conductive sealing material composition thus configured, carbon fiber is blended in the modified polysulfide or modified silicone sealing material composition, so that the sealing material can be provided with conductivity, and an antistatic material or electromagnetic wave shielding can be provided. It is suitable for a sealing material that closes joints of building members such as materials.
JP-A-7-31014 (Claim 1, paragraph [0074])

However, in the conductive sealing material composition shown in the above-mentioned conventional patent document 1, since carbon fiber is used as a fiber for imparting conductivity to the sealing material, electric resistance is larger than that of metal, and a large amount is blended. Otherwise, there was a problem that a predetermined electromagnetic wave shielding effect could not be obtained.
Moreover, in the conductive sealing material composition shown in the above-mentioned conventional Patent Document 1, since the carbon fiber has a large oil absorption, the carbon fiber absorbs a large amount of modified polysulfide polymer and the like, and the viscosity of the conductive sealing material is extremely high. There is also a problem that the workability at the time of coating the conductive sealant is lowered.
An object of the present invention is to obtain a predetermined electromagnetic wave shielding effect only by dispersing a relatively small amount of resin fibers coated with a metal, and electrically and structurally cut gaps and joints that are cut electrically and structurally. It is an object of the present invention to provide a method of manufacturing an electromagnetic wave shielding sealing material that can be securely connected.
Another object of the present invention is to provide an electromagnetic wave shielding sealing material that can improve coating workability by suppressing the increase in viscosity by extremely reducing the amount of suction of the main component resin by the resin fiber coated with metal. It is to provide a manufacturing method.
Yet another object of the present invention is to reduce the amount of water contained in the modified silicone sealant before mixing the metal-coated resin fibers and the reaction catalyst, thereby improving the storage stability of the electromagnetic wave shielding sealant. An object of the present invention is to provide a method for producing an electromagnetic wave shielding sealant that can improve the efficiency.

The invention according to claim 1 includes a step of adding a plasticizer and a filling reinforcing agent to a modified silicone resin and mixing them to prepare a modified silicone sealant, and dehydrating the modified silicone sealant to be included in the modified silicone sealant. A step of reducing moisture to 0.1% by weight or less, a step of cutting conductive fibers by cutting resin fibers coated with metal into a length of 0.5 to 3 mm, and a dehydrated modified silicone sealant A method of producing an electromagnetic wave shielding sealing material comprising: a step of preparing a mixture by mixing conductive fibers and an adhesion-imparting agent; and a step of mixing a reaction catalyst with the mixture and then storing the mixture in a sealed container and blocking from air. is there.
In the method for producing an electromagnetic wave shielding sealant according to claim 1 , before the resin fiber coated with metal and the adhesion-imparting agent are mixed, the water content contained in the modified silicone sealant is 0.1% by weight. Since it is extremely small as described below, the electromagnetic wave shielding sealing material contains almost no moisture, and does not harden even if the electromagnetic wave shielding sealing material is stored in a sealed container for a long period of time.
The invention according to claim 2 is the invention according to claim 1, wherein the resin fiber is a polyester fiber, an acrylic fiber, a polyamide fiber or a polyolefin resin.
The invention according to claim 3 is the invention according to claim 1, characterized in that the metal is silver, copper, nickel, ferrite, stainless steel, aluminum, gold, or platinum.
The invention according to claim 4 is the invention according to claim 1, further comprising dispersing 3 to 10% by weight of a metal fiber-coated resin fiber with respect to 100% by weight of the modified silicone sealant, and the thickness of the resin fiber. Is 0.1 to 15d and the length is 0.5 to 3 mm.

Above As I mentioned, according to the present invention, moisture 0.1 wt% or less contained by dehydrating the modified silicone sealant mixed by adding plasticizer to the denatured silicone resin to the modified silicone sealant The resin fibers coated with metal are cut to a length of 0.5 to 3 mm to produce conductive fibers, and the conductive fibers and the adhesion-imparting agent are mixed with the dehydrated modified silicone sealant. If the mixture is further mixed with a reaction catalyst and then contained in a sealed container and shielded from the air to produce an electromagnetic wave shielding sealing material, the electromagnetic wave shielding sealing material contains almost no moisture. Even when the electromagnetic wave shielding sealing material is stored in a sealed container and stored for a long period of time, it does not harden. As a result, the storage stability of the electromagnetic wave shielding sealant can be improved.

Next, the best mode for carrying out the present invention will be described.
The electromagnetic wave shielding sealant of the present invention is obtained by dispersing 3 to 10% by weight, preferably 3 to 5% by weight, of a resin fiber coated with a metal with respect to 100% by weight of a modified silicone sealant. Here, the dispersion amount of the resin fiber coated with the metal is limited to the range of 3 to 10% by weight. If the amount is less than 3% by weight, a predetermined electromagnetic wave shielding effect cannot be obtained due to a decrease in the contact ratio of each resin fiber. This is because if the content exceeds 10% by weight, the viscosity of the electromagnetic wave shielding sealant increases and the coating workability of the electromagnetic wave shielding sealant decreases. In the present specification, the predetermined electromagnetic wave shielding effect is obtained when an electromagnetic wave shielding sealing material is applied to a gap between a metal window frame and a window glass with a conductive film or a joint between metal panels and cured. This is an effect of shielding (shielding) the electromagnetic wave generated, and specifically means that the surface resistivity when applied and cured is in the range of 0.1 to 5Ω / □. The electromagnetic wave shielding sealing material is 50 to 120% by weight of a plasticizer that imparts flexibility and elasticity to the electromagnetic wave shielding sealing material with respect to 100% by weight of the modified silicone resin, and the electromagnetic wave shielding sealing material is flexible. 135 to 195% by weight of the filler reinforcing agent, 3 to 7% by weight of the adhesive imparting adhesiveness to the electromagnetic wave shielding sealant, and 2 to 4% by weight of the reaction catalyst are added. Examples of the plasticizer include polypropylene glycol (PPG) and polyethylene glycol (PEG). Examples of the filling reinforcing agent include titanium oxide particles, calcium carbonate particles, and silica particles having an average particle size of 100 μm. Examples of the adhesion imparting agent include silane coupling agents and silicates, and examples of the reaction catalyst include organic tin, organic amine, and organic zinc.

  On the other hand, the thickness of the resin fiber is 0.1 to 15 d (denier), preferably 1 to 10 d, and the length of the resin fiber is 0.5 to 3 mm, preferably 1 to 3 mm. The metal coating amount is preferably 5 to 50% by weight. Here, the thickness of the resin fiber is limited to the range of 0.1 to 15d because if less than 0.1d, the amount of the resin fiber covered with metal increases and the overall weight increases. This is because the amount of coating with the metal can be reduced, but the resin fiber becomes hard and the viscosity of the electromagnetic wave shielding sealant increases. Further, the length of the resin fiber is limited to the range of 0.5 to 3 mm because if the resin fiber is less than 0.5 mm, a predetermined conductivity cannot be obtained unless a large amount of the resin fiber is added. This is because the viscosity of the coating increases and the coating workability of the electromagnetic wave shielding sealant decreases. Further, the metal coating amount is limited to the range of 5 to 50% by weight. If it is less than 5% by weight, the resin fibers cannot be sufficiently coated, and the conductivity is greatly lowered, and a satisfactory electromagnetic shielding effect cannot be obtained. This is because if the weight percentage is exceeded, the overall weight increases and the conductivity of the resin fiber coated with metal reaches its peak. The metal preferably covers the entire surface of the resin fiber, and the thickness of the coating is about 0.1 μm. Examples of the resin fiber include polyester fiber, acrylic fiber, polyamide fiber, and polyolefin resin, and examples of the metal include silver, copper, nickel, ferrite, stainless steel, aluminum, gold, and platinum.

A method for manufacturing the electromagnetic wave shielding sealant configured as described above will be described.
First, 50 to 120% by weight of a plasticizer and 135 to 195% by weight of a filler reinforcing agent are added to 100% by weight of a modified silicone resin and mixed to prepare a modified silicone sealant. Next, the modified silicone sealant is added to 100% by weight of the modified silicone sealant. On the other hand, the conductive fiber and the adhesion-imparting agent are added to the modified silicone sealant and mixed so that the conductive fiber is 3 to 10% by weight and the adhesion-imparting agent is 3 to 7% by weight. Furthermore, an electromagnetic wave shielding sealant is produced by adding the reaction catalyst to the mixture and mixing the mixture so that the reaction catalyst is 2 to 4% by weight with respect to 100% by weight of the modified silicone sealant. In addition, after producing the modified silicone sealant, the modified silicone sealant is dehydrated, and the moisture contained in the modified silicone sealant is 0.1% by weight or less, preferably 0.03 to 0.07% by weight. To reduce. As a dehydration method, a method of evaporating water by maintaining at a temperature of 80 to 90 ° C. for 4 to 16 hours under reduced pressure to 0.098 to 0.10 MPa, or adding a methyl silane coupling agent having a dehydration action is added. And a method of removing moisture. Here, the moisture contained in the modified silicone sealant is dehydrated to 0.1% by weight or less because when it exceeds 0.1% by weight, the electromagnetic wave caused by the moisture is stored for a long time even in a sealed state. This is because the curing reaction of the shielding sealing material is accelerated and the electromagnetic shielding sealing material is cured. Further, when the moisture contained in the modified silicone sealant is dehydrated to less than 0.03% by weight, the curing rate is suppressed when the electromagnetic wave shielding sealant is applied to a predetermined location. The moisture contained is preferably 0.03% by weight or more. Further, the conductive fiber is produced by cutting a resin fiber coated with metal into a length of 0.5 to 3 mm. Here, in order to coat the resin fibers with metal, an electroless plating method, a vacuum deposition method, or the like is used. The above-mentioned electromagnetic wave shielding sealant is immediately stored in a sealed container after production to prevent curing, and is shielded from air.

In the electromagnetic wave shielding sealant thus produced, a predetermined electromagnetic wave shielding effect can be obtained only by dispersing a relatively small amount of resin fiber coated with a metal at 3 to 10% by weight in a modified silicone sealant. As a result, the electrically and structurally cut parts such as the gap between the metal window frame and the window glass with the conductive film and the joint between the metal panels are electrically and structurally surely secured by the electromagnetic wave shielding sealing material. Can connect.
In addition, since the resin fiber coated with metal hardly absorbs the modified silicone sealant, the viscosity of the electromagnetic wave shielding sealant does not increase. As a result, when the electromagnetic wave shielding sealant is applied to the gap between the metal window frame and the window glass with the conductive film or the joint between the metal panels, the electromagnetic wave shielding sealant is quickly adapted to the shape of the gap or joint. Since it is deformed, the coating workability of the electromagnetic wave shielding sealant can be improved.

Next, embodiments of the present invention will be described in detail.
<Example 1>
First, after preparing a modified silicone sealant by adding and mixing 90% by weight of a plasticizer and 165% by weight of a filler reinforcing agent with respect to 100% by weight of a modified silicone resin (manufactured by Kaneka Chemical Co., Ltd .: MS polymer). The modified silicone sealant was dehydrated to reduce the moisture contained in the modified silicone sealant to 0.05% by weight. On the other hand, 2d (denier) polyester fiber coated with silver was cut into a length of 3 mm to produce a conductive fiber. Next, the conductive fiber and the adhesion-imparting agent are added to the dehydrated modified silicone-based sealant so that the conductive fiber is 3% by weight and the adhesion-imparting agent is 5% by weight with respect to 100% by weight of the modified silicone-based sealant. Each was added and mixed to prepare a mixture. Furthermore, an electromagnetic wave shielding sealant was produced by adding and mixing the reaction catalyst to the mixture so that the reaction catalyst was 3% by weight with respect to 100% by weight of the modified silicone sealant. Further, the electromagnetic wave shielding sealant was immediately stored in a sealed container after production to prevent curing. The electromagnetic wave shielding sealing material accommodated in this hermetic container was referred to as Example 1.

<Comparative Example 1>
An electromagnetic shielding sealant was produced in the same manner as in Example 1, except that flaky nickel powder was added in an amount of 20% by weight based on 100% by weight of the modified silicone resin instead of the conductive fiber of Example 1. This is Comparative Example 1.
<Comparative Example 2>
In the same manner as in Example 1, except that carbon powder (Tokai Carbon Co., Ltd .: Toka Black) was added in an amount of 10% by weight based on 100% by weight of the modified silicone resin instead of the conductive fiber of Example 1. A shielding sealant was produced. This is Comparative Example 2.
<Comparative Example 3>
In the same manner as in Example 1, except that carbon powder (manufactured by Lion Corporation: EC600-JD) was added in an amount of 8% by weight with respect to 100% by weight of the modified silicone resin instead of the conductive fiber of Example 1. A shielding sealant was produced. This is Comparative Example 3.

<Comparative test 1 and evaluation>
A square hole with vertical and horizontal lengths of 500 mm and 40 mm is formed in the shield room wall (thickness 10 mm), an aluminum sash frame is fitted into the square hole, and an electromagnetic wave shielding window is inserted into the aluminum sash frame. did. The difference in electric field strength between the case where nothing is filled between the square hole and the aluminum sash frame and the case where the electromagnetic wave shielding sealant of Example 1 and Comparative Examples 1 to 3 is filled is expressed in dB as the shielding performance. did. Specifically, first, an electromagnetic wave having a predetermined frequency was radiated from a transmitter in a shield room without applying an electromagnetic wave shielding sealant, and the output of the transmitter was adjusted to 110 dBμV outside the shield room. . Next, with the electromagnetic wave shielding sealant applied, the electromagnetic field having the predetermined frequency was radiated from the transmitter, and the electric field strength leaking out of the shield room was measured. The difference in electric field strength was expressed as dB as the shielding performance. Table 1 shows the measurement results obtained by sequentially changing the predetermined frequency to 500 MHz, 1000 MHz, 2000 MHz, and 3000 MHz.

  As is clear from Table 1, in Comparative Examples 1 to 3, the shielding performance was as low as 15 to 25 dB, whereas in Example 1, the shielding performance was as high as 30 to 35 dB.

Claims (4)

Adding a plasticizer and a filling reinforcing agent to the modified silicone resin and mixing them to produce a modified silicone sealant;
Dehydrating the modified silicone sealant to reduce the moisture contained in the modified silicone sealant to 0.1% by weight or less;
Cutting the resin fibers coated with metal into a length of 0.5 to 3 mm to produce conductive fibers;
Mixing the conductive fibers and an adhesion-imparting agent with the dehydrated modified silicone sealant to produce a mixture;
A method for producing an electromagnetic wave shielding sealing material, comprising: mixing a reaction catalyst with the mixture, and then housing the reaction catalyst in a sealed container and shielding the air from air. The method for producing an electromagnetic wave shielding sealant according to claim 1, wherein the resin fiber is a polyester fiber, an acrylic fiber, a polyamide fiber or a polyolefin resin . The method for producing an electromagnetic wave shielding sealant according to claim 1, wherein the metal is silver, copper, nickel, ferrite, stainless steel, aluminum, gold, or platinum . The resin fiber coated with the metal is dispersed in an amount of 3 to 10% by weight with respect to 100% by weight of the modified silicone sealant, and the thickness of the resin fiber is 0.1 to 15d and the length is 0.5 to 5%. The method for producing an electromagnetic wave shielding sealant according to claim 1, which is 3 mm.