JP2003243873A - Flame retardant gasket for shielding electromagnetic wave - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasket for shielding an electromagnetic wave having an excellent flame retardance without generating a harmful halogen gas at a combustion time, and without using an antimony called to be harmful for a human body in the gasket having the excellent flame retardance and electromagnetic wave shielding properties. <P>SOLUTION: The gasket for shielding the electromagnetic wave comprises a foamed material having the flame retardance as a core, and a metal-coated cloth 2 having a resin layer 1 obtained by adding a flame retardant agent to at least one surface of the cloth by using a halogen flame retardant agent, an antimony flame retardant agent and at least a phosphorus compound flame retardant agent, and an unexpanded thermal expansible graphite except a flame retardant agent containing an allotrope of the phosphorus such as a red phosphorus and laminated on the cloth 2 as the agent on the outer surface of the core and wound on the core. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant electromagnetic wave shielding gasket, which does not generate a harmful halogen-based gas at the time of combustion and does not use antimony which is said to have a bad effect on the human body, and is excellent. And a gasket for electromagnetic wave shielding having flame retardancy.

[0002]

2. Description of the Related Art In recent years, along with the spread of not only home electric appliances but also various information terminals such as personal computers, mobile phones, and video games, electromagnetic waves leaking from these devices cause malfunctions of other electronic devices and health of users. There is concern about the impact on. In order to prevent these obstacles, an electromagnetic wave shielding material having excellent electromagnetic wave shielding performance is required. Further, due to the enforcement of the Product Liability Law (PL Law) and the like, flame retardant performance is required not only for home electric appliances but also for these electromagnetic wave shielding materials. There is a demand for products that meet the standards.

On the other hand, the problem of environmental pollution has come to be discussed on a global scale, and it is required to prevent environmental pollution not only at the time of combustion but also at the time of disposal. In other words, when incinerated, harmful gases such as dioxins are not generated, and when the electromagnetic wave shielding material is disposed of as waste, it is also required that harmful substances in the waste do not contaminate water quality or soil. Is becoming. Therefore, regarding the flame retardant used for the electromagnetic wave shielding material, a halogen-based flame retardant that may generate dioxin, an antimony-based flame retardant that uses antimony that is harmful to the human body, or is highly toxic or phosphine during combustion. The use of flame retardants of phosphorus allotropes such as red phosphorus, which generates gas, has become a problem.

As a means for solving the above-mentioned problems, Japanese Patent Laid-Open No.
According to Japanese Patent Laid-Open No. 001-11285, a foam made of a melamine resin having flame retardancy is used as a core material, a resin layer containing a flame retardant is formed on the outer surface of the core material, and a metal plating layer is formed on the resin layer. It is disclosed that a gasket for electromagnetic wave shielding having high flame retardancy is obtained. However, the gasket for electromagnetic wave shielding obtained by this method has a resin layer having a flame retardant lacking in abrasion resistance and abrasion resistance, and the metal plating layer is easily peeled off, resulting in deterioration of flame retardancy and electromagnetic wave shielding property. There is a problem with durability as an electromagnetic shield gasket, such as easy occurrence. Furthermore, since the number of manufacturing steps is large and the processing time is long, the productivity and economy are poor.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and its object is to provide a halogen-based compound which may generate a harmful gas during combustion, and an antimony which is harmful to a human body. It is intended to obtain an electromagnetic wave shield gasket having excellent flame retardancy without using.

[0006]

The present invention has been made as a result of intensive studies for the purpose of solving the above problems, and has the following constitution. That is, the present invention is, firstly, a metal coating in which a core material made of a synthetic resin foam having flame retardancy is laminated on the outside with a resin layer containing at least a phosphorus compound flame retardant and unexpanded thermally expansive graphite. It is an electromagnetic wave shielding gasket formed by winding a cloth. Secondly, a resin layer containing a phosphorus-based compound flame retardant and unexpanded thermally expansive graphite, in the electromagnetic shielding gasket according to the first aspect, characterized in that it is formed on at least one surface of the metal-coated cloth. is there. Thirdly, with respect to the weight of the metal cloth, 40 to 300% of phosphorus compound flame retardant and 20 to 160% of unexpanded thermally expansive graphite are contained, and the electromagnetic wave shield according to the first or second aspect. For gasket. Fourthly, there is provided the electromagnetic wave shielding gasket according to the first to third aspects, wherein the phosphorus compound flame retardant is ammonium polyphosphate.

The foam used as the core material in the present invention is preferably a flame-retardant foam having a three-dimensional structure which is flexible and rich in compression recovery. Examples of these foams include foams made of silicone resin, melamine resin, and other synthetic resins that are characterized by flame resistance, and polyethylene resin, polypropylene resin, polyurethane resin, polyester resin, polyimide resin, polybutadiene resin, etc. A foam which is foamed after the addition of a flame retardant, or a foam which is impregnated with a flame retardant after foaming or is applied by a coating method or a method such as a spray method may be used. Among the foams, a polyurethane resin foamed by adding a flame retardant is preferably used because it is flexible and rich in compression-restoration, has a small number of steps, and is economical.

The flame retardant used is not limited to halogen-based flame retardants, antimony-based flame retardants, and flame retardants composed of phosphorus allotrope, but also phosphorus-based compound flame retardants, unexpanded thermally expansive graphite, and the like. Flame retardants such as magnesium hydroxide and hydrated metal compounds such as aluminum hydroxide can be used, and they can be used in combination and are not particularly limited.

The form of the cloth used in the present invention includes woven fabric, knitted fabric and non-woven fabric, and is not particularly limited.
Further, the fibers constituting the cloth are synthetic compounds such as halogen-based compounds, antimony oxide, red phosphorus-free polyester, polyamide, acrylic and polyolefin, semi-synthetic fibers such as acetate, regenerated fibers such as rayon, and other natural fibers. Although fibers may be mentioned, polyester fibers are most preferable in view of processability and durability.

In order to ensure the fixing of the metal coating on the cloth made of these fibers, impurities such as sizing agent, oil agent, dust, etc., which have adhered to the surface of the fiber in advance, are completely removed by a scouring treatment. Preferably. A conventionally known method is used for the scouring treatment and is not particularly limited.

Examples of the metal to be coated include gold, silver, copper, zinc, nickel, and alloys thereof, but copper and nickel are preferable in view of the shielding property and the manufacturing cost. The coating layer formed of these metals is preferably one layer or two layers. When the number of layers is three or more, the metal coating layer becomes thick, the conductive woven fabric may be hardened, and the processing cost is increased. When the metal coating layer is laminated in two layers, the same kind of metal may be laminated in two layers, or different metals may be laminated. These can be appropriately set in consideration of desired shieldability and durability.

Further, the metal film forming method includes vapor deposition, sputtering, electroplating method, electroless plating method and the like. In terms of uniformity of the metal film to be formed and productivity, the electroless plating method, or A combination of electroless plating and electroplating is preferably used.

As a method of applying the flame retardant to the cloth on which the metal coating layer is formed, a method of applying a resin in which the flame retardant is dispersed and mixed to the cloth is preferable. Examples of the resin used include synthetic resins such as urethane resin, acrylic resin, and ester resin, and urethane resin is preferably used. Urethane resins are more easily flame-retardant than acrylic resins and ester resins, and are superior in terms of frictional strength and flexibility. The amount of resin applied is preferably 60 to 400 g / m ^{2, and} more preferably 100 to 250 g / m ² . If it is less than this range, sufficient flame retardancy cannot be obtained, and if it is too large, the texture becomes hard, which is economically disadvantageous. The resin application method may be a coating method such as a floating method, a knife coater method, or a roll coater method, and is not particularly limited. Further, the viscosity of the imparted resin containing the flame retardant is 2000 to 3000.
The range of 0 cps is preferable, and more preferably 4000 to
A range of 15000 cps is preferred. Viscosity is 2000c
If it is lower than ps, the resin may leak back to the opposite surface and hinder the appearance quality. If the viscosity is higher than 30,000 cps, the coatability will be poor. Further, for the purpose of preventing back leakage of the resin containing the flame retardant, a resin layer for preventing back leakage may be formed in advance on the same surface before applying the resin containing the flame retardant. As the resin for preventing back leakage, acrylic resin is preferable from the viewpoint of workability, flexibility and economy. The applying method includes a floating method, a knife coater method, a roll coater method and the like, and any method may be used. The viscosity of the applied resin is 2000 to 30,000 cps, and more preferably 10,000 to 15,000 cps. 200
If it is lower than 0 cps, the resin may be back-leaked to impair the appearance, and if it is higher than 30,000 cps, the coatability is deteriorated.
The coating amount is 1 to 10 g / m ² , preferably 3 to 7 g / m ^2.
Is the range. If the coating amount is less than 1 g / m ² , the back leakage prevention of the resin containing the flame retardant cannot be sufficiently exerted and 10 g / m ²
If it is more than m ² , flame retardancy may be impaired.

The flame retardant used in the metal-coated cloth is formed of at least a phosphorus compound flame retardant and unexpanded thermally expansive graphite. Phosphorus-based compound flame retardants include phosphoric acid ester-based compounds such as bisphenol A bis (diphenyl phosphate) and resorcinol bis (di-2,6-xylyl) phosphate, phosphoric amide-based compounds such as triphenylphosphamide, and ammonium polyphosphate. Examples thereof include ammonium polyphosphate, and ammonium polyphosphate is particularly preferably used because it has a high phosphorus content and an excellent flame retardant effect. Moreover, since the simple substance of ammonium polyphosphate has poor moisture resistance, it may be decomposed if left in a high humidity environment for a long time. Therefore, decomposition and deterioration can be suppressed by using a type whose surface is coated with a melamine resin. Phosphorus allotropes such as red phosphorus have a flame-retardant effect, but are not preferable because they are highly toxic or generate highly toxic phosphine gas. In addition, unexpanded thermally expandable graphite has a structure in which sulfuric acid is layered inside crystalline graphite flakes, and when the sulfuric acid is vaporized during combustion, the graphite flakes are about 100 times the original thickness. Expands to. For this reason, a large heat insulating layer is formed, and the expanded graphite can greatly reduce the heat generation rate, thermal decomposition, and smoke generation, and at the same time, has the effect of preventing the diffusion of the combustible compound generated inside the fiber. Examples of heat-expandable graphite that can be used include natural graphite, pyrolytic graphite, quiche graphite, and other inorganic acids (concentrated sulfuric acid, nitric acid, etc.) and strong oxidizers (perchloric acid, perchlorate, hydrogen peroxide solution, etc.). ) And a mixture treated with an acid. Further, it is also possible to use an acid-treated mixture of ammonium persulfate and the like, and after the acid treatment, an aliphatic lower amine such as monomethylamine, an alkali metal compound or an alkaline earth metal compound (potassium, sodium, calcium, barium,
It is also possible to use those which have been neutralized with hydroxides such as magnesium, oxides, carbonates, lead sulfates, etc.
Specific examples thereof include graphite acid lead sulfate, sodium graphite, potassium graphite, graphite oxide, graphitized aluminum chloride, and ferric oxide graphite, and one or more of these can be used. The particle size of unexpanded thermally expansive graphite is 10-
1000 μm is preferable. When the particle size is smaller than 10 μm, the degree of expansion of graphite is small, and as a result, the flame retardancy is lowered,
On the other hand, if it is larger than 1000 μm, the expansion of the graphite is large and the flame retardancy is good, but the dispersibility becomes poor when it is added to the resin and kneaded, and the quality of the resin coated surface is affected. These flame retardants may be contained in the resin in a mixed and dispersed state, or may be dispersed and blended in the resin for each flame retardant. When the resin containing these flame retardants is applied to the fiber and dried, the resin and the resin are fixed to the fiber.
The ratio of the flame retardant to the resin in which the flame retardant is added and kneaded is a solid content ratio, the phosphorus compound flame retardant is 120 to 190% by weight, and the thermally expandable graphite is 60 to 100% by weight. When the ratio is higher than this range, the resin coating becomes brittle, and when the ratio is low, sufficient flame retardancy cannot be obtained. Further, the phosphorus compound flame retardant is 40 to 300% by weight, based on the weight of the metal-coated cloth,
Preferably 70 to 190% by weight, unexpanded thermally expandable graphite is 20 to 160% by weight, preferably 35 to 100% by weight.
It is preferable to be included in the range of. If it is less than these ratios, sufficient flame retardancy may not be obtained, and if it is more than these ratios, further improvement of flame retardancy may not be expected and the cost may increase. In the present invention, the flame retardant used for the metal-coated cloth, as described above, is essentially a phosphorus compound flame retardant and an unexpanded thermally expansive graphite. Other than flame retardants and flame retardants consisting of allotropes of phosphorus,
For example, a flame retardant such as magnesium hydroxide or a hydrated metal compound such as aluminum hydroxide can be used in combination. Further, the resin layer containing the flame retardant may be formed not only on one surface of the cloth but also on both surfaces of the cloth. That is, the resin containing the flame retardant as described above may be laminated on one surface, and then the resin containing the same flame retardant may be laminated on the other surface. The coating amount of the resin containing the flame retardant on the opposite surface is preferably 1 to 10 g / m ² , and more preferably ^{3 to} 8 g / m ² . If it is less than 1 g / m ² , the flame retardant effect cannot be obtained, and if it is more than 10 g / m ² , the surface conductivity is deteriorated.
The applying method includes a coating method such as a floating method, a knife coater method, and a roll coater method, and any method may be used.

As a method of winding a flame-retardant metal-coated cloth on a flame-retardant foam material as a core material,
First, there is a method in which a foam is cut into a desired size and a metal-coated cloth having flame retardancy is wound on the outer surface of the foam. As a method for adhering the wound metal-coated cloth and the foam, an adhesive is applied to the adhering surface of the metal-coated cloth or the foam, or a double-sided adhesive tape is used for adhesion. As the adhesive or the like, either a pressure sensitive adhesive or a heat sensitive adhesive can be used. Furthermore, adding a flame retardant to the adhesive used here,
By using the double-sided pressure-sensitive adhesive tape containing a flame retardant, higher flame retardancy can be obtained, which is effective. However, the flame retardants used are halogen compounds, red phosphorus,
Phosphorus compounds excluding antimony oxide are preferred. The metal-coated cloth may be bonded to the foam on either side, but it is more preferable to bond the resin-coated surface to the foam in order to obtain a conductive effect. Secondly, a tubular metal frame of a desired size is prepared in advance, a flame-retardant metal-coated cloth is laid along the inside of the tube, and inside the tube, a foaming agent made of a flame-retardant resin is formed. It can also be obtained by adding and foaming a resin or a foaming resin containing a flame retardant.

[0016]

EXAMPLES The evaluation methods for the products of the present invention in Examples and Comparative Examples are as follows. Flame retardance evaluation It is evaluated according to V-1 of UL94. Surface conductivity HIOKI ELECTRIC CO., LTD. Resistance value measuring device Milliohm High Tester 3220 is used, and clip parallel electrode width 10c
The resistance value was measured at m and a distance between the electrodes of 10 cm. The unit is Ω / □. Shielding evaluation A measurement cell similar to the one developed by the Ikoma Radio Measurement Station of Kansai Electronics Industry Promotion Center was created, and a spectrum analyzer with tracking generator HP8591EM manufactured by Hewlett Packard Co. was used for 10 MHz to 1G.
The Hz oscillation was received by the cell receiving section through the measurement sample and measured by the spectrum analyzer. Unit is d
B.

[0017]

Example 1 Polyester fiber woven fabric (warp yarn 56 dtex
/ 24f, weft 56dtex / 36f) is scoured and dried,
After heat treatment, palladium chloride 0.3g / L,
After dipping in an aqueous solution containing 30 g / L of stannous chloride and 300 ml / L of 36% hydrochloric acid at 40 ° C. for 2 minutes, it was washed with water. continue,
After soaking in hydrofluoric acid having an acid concentration of 0.1 N at 30 ° C. for 5 minutes, washing with water, and then electroless copper comprising copper sulfate 7.5 g / L, 37% formalin 30 ml / L, and Rochelle salt 85 g / L It was immersed in the plating solution at 30 ° C. for 5 minutes and then washed with water. Subsequently, nickel sulfamate 300 g / L, boric acid 30
g / L, nickel chloride 15 g / L, pH 3.7 electro-nickel plating solution at 35 ° C. for 10 minutes, current density 5 A / d
It was dipped in m ² to stack nickel and then washed with water. Copper 10 g / m ² in the fabric, the nickel is 4g / m ² Plating. The metal-coated fabric obtained had a weight of 64 g / m ² . To prevent back leakage of the resin on one side of the obtained metal-coated woven fabric, a resin of the following formulation 1 was applied by a floating knife method, and 1
It was dried at 30 ° C. The coating amount was 4 g / m ² in terms of solid content. Subsequently, the resin of Formulation 2 was applied to the same surface by a knife-on-roll method and dried at 130 ° C. The coating amount was 140 g / m ² in terms of solid content. The proportions of the phosphorus compound flame retardant and the thermally expandable graphite used were 100% by weight and 53% by weight, respectively, with respect to the weight of the metal-coated woven fabric. Furthermore, in order to bond the metal-coated fabric and the foam on the same surface,
A urethane resin foam obtained by coating the pressure-sensitive adhesive resin of Formulation 3 at a solid content of 5 g / m ² by a floating knife method and adding a phosphorus-based flame retardant (Everlite DO manufactured by Bridgestone Corporation). ) Was wound on the outer surface to obtain a gasket material for electromagnetic wave shielding. The performance evaluation results are shown in Table 1. Prescription 1 Toacron SA-6218 100 parts (Toupe Co., Ltd., acrylic resin, solid content 18%) Resamine UD crosslinking agent 1.5 parts (Dainichi Seika Chemicals Co., Ltd., isocyanate crosslinking agent, solid content 75%) Toluene is added to adjust the viscosity to 15000 cps. Prescription 2 Crisbon 5116EL 100 parts (Dainippon Ink and Chemicals, Inc., urethane resin, solid content 30%) Ammonium polyphosphate 45 parts (solid content 100%) Unexpanded thermally expansive graphite 24 parts (solid content 100%) Methyl ethyl ketone is added to adjust the viscosity to 8000 cps. Prescription 3 Crisbon TA-465 100 parts (Dainippon Ink and Chemicals, Inc., urethane resin, solid content 65%) Resamine UD crosslinking agent 8 parts (Dainichi Seika Chemicals Co., Ltd., urethane resin crosslinking agent, solid content 75%) ) Viscosity is adjusted to 9000 cps by adding toluene to 3 parts of Crisbon Accel HM (manufactured by Dainippon Ink and Chemicals, Inc., urethane resin crosslinking accelerator, solid content 15%).

[0018]

Example 2 On one side of the metal-coated woven fabric prepared in Example 1, the resin of Formula 1 was applied by the floating knife method to prevent back leakage of the resin, and dried at 130 ° C. The coating amount was 4 g / m ² in terms of solid content. Subsequently, the resin of the formulation 2 is applied to the same surface by a knife-on-roll method,
It was dried at ° C. The coating amount was 140 g / m ² in terms of solid content. Further, a resin of Formulation 4 was applied to the same surface by a floating knife method so as to have a solid content of 20 g / m ² for adhering the metal-coated woven fabric and the foam, and dried at 130 ° C. The proportions of the phosphorus compound flame retardant and the thermally expandable graphite used were 112% by weight and 53% by weight, respectively, with respect to the weight of the metal-coated woven fabric. Next, the resin laminated surface of Formulation 4 of the metal-coated woven fabric described above is attached to the outer surface of the foam (Everlite DO manufactured by Bridgestone Corporation) in which the phosphorus-based flame retardant is added to the urethane resin for foaming. And wrap it around the metal-coated fabric with a hot press at 130 ° C for 3
It was pressed for 0 seconds to obtain an electromagnetic wave shielding gasket material of Example 2. The performance evaluation results are shown in Table 1. Prescription 4 UD1305 100 parts (Dainichi Seika Kogyo Co., Ltd., urethane resin, solid content 50%) Nonnene R-0111-4 30 parts (Marubishi Yuka Kogyo Co., Ltd., phosphorus / nitrogen compound flame retardant, solid content 100%) ) Is added with methyl ethyl ketone to adjust the viscosity to 8000 cps.

[0019]

Example 3 The resin of Formula 1 was applied to one side of the metal-coated cloth prepared in Example 1 by the floating knife method, and 1
It was dried at 30 ° C. The coating amount was 4 g / m ² in terms of solid content. Subsequently, the resin of Formulation 2 was applied to the same surface by a knife-on-roll method and dried at 130 ° C. The coating amount was 140 g / m ² in terms of solid content. Furthermore, the resin of the formulation 5 is applied to the opposite surface of the woven fabric by the floating knife method, and 1
It was dried at 30 ° C. The coating amount was 10 g / m ² in terms of solid content. Next, the resin of Formulation 3 for adhering the metal-coated woven fabric and the foam was applied to the surface coated with the resin of Formulation 2 by a floating knife method at a solid content of 140 g / m ² . The phosphorus compound flame retardant used in the obtained metal-coated woven fabric and the heat-expandable graphite metal-coated woven fabric were 108% by weight and 53% by weight, respectively. Subsequently, the foamed material having a phosphorus-based flame retardant (Everlite DO manufactured by Bridgestone Corporation) was wound on the outer surface so as to be bonded to the surface on which the resin of Formula 3 of the metal-coated fabric was laminated, and the gasket for electromagnetic wave shielding. was gotten. The performance evaluation results are shown in Table 1. Prescription 5 Toacron SA-6218 100 parts (manufactured by Tope Co., acrylic resin, solid content 18%) Nonnen R0111-4 20 parts (Maruhishi Yuka Kogyo Co., Ltd., phosphate ester compound flame retardant, solid content 100) %)

[0020]

Example 4 On one side of the metal-coated cloth prepared in Example 1, the resin of Formula 1 was applied by the floating knife method,
It was dried at 130 ° C. The coating amount was 4 g / m ² in terms of solid content. Subsequently, a resin was applied to Formulation 2 on the same surface by a knife-on-roll method and dried at 130 ° C. The coating amount was 140 g / m ² in terms of solid content. The proportions of the phosphorus compound flame retardant and the thermally expandable graphite used were 100% by weight and 53% by weight, respectively, with respect to the weight of the metal-coated woven fabric. This woven fabric is made to run along the side surface inside the mold frame that is cylindrical with a prismatic shape with the resin laminated surface inside. After that, the silicone resin of formulation 6 is poured into the solution after stirring the solution, and foamed. When the foaming was completed, it was taken out from the metal frame to obtain an electromagnetic wave shielding gasket. The performance evaluation results are shown in Table 1. Prescription 6 SE1900 A 100 parts (Toray Dow Corning Silicone Co., Ltd. silicone resin) SE1900 B 100 parts (Toray Dow Corning Silicone Co., silicone resin)

Example 5 The resin of Formulation 1 was applied to one surface of the metal-coated woven fabric prepared in Example 1 by the floating knife method and dried at 130 ° C. Coating amount is 3g / m in solid content
It was ² . Then, the resin of Formulation 7 was applied to the same surface by a floating knife method and dried at 130 ° C. The coating amount was 140 g / m ² in terms of solid content. The proportions of the phosphorus compound flame retardant and the thermally expandable graphite used were 102% by weight and 66% by weight, respectively, with respect to the weight of the metal-coated woven fabric. Subsequently, in order to adhere the metal-coated woven fabric and the foam to the same surface, a resin of Formulation 3 was applied at a solid content of 5 g / m ² by a floating knife method, and a urethane foam having a phosphorus-based flame retardant ( Prescription of metal-coated woven fabric mentioned above on the outer surface of Everlight DO manufactured by Bridgestone Corporation 3
It was wound so as to be stuck to the resin laminated surface of (1) to obtain an electromagnetic wave shielding gasket. The performance evaluation results are shown in Table 1. Prescription 7 Crisbon 5116EL 100 parts (Dainippon Ink and Chemicals, Inc., urethane resin) Nonnene R0111-4 60 parts (Marubishi Yuka Kogyo Co., Ltd., phosphate ester compound flame retardant) Unexpanded thermally expansive graphite 40 parts Methyl ethyl ketone is added to (solid content 100%) to adjust the viscosity to 7500 cps.

[0021]

Comparative Example 1 The resin of Formulation 1 was applied to one surface of the metal-coated woven fabric used in Example 1 by the floating knife method and dried at 130 ° C. The coating amount was 3 g / m ² in terms of solid content. Next, a resin of the following formulation 8 was applied on the same surface by a floating knife method and dried at 130 ° C. The coating amount was 140 g / m ² in terms of solid content. The ratio of the phosphorus compound flame retardant used to the weight of the metal-coated fabric is
It was 80% by weight. Subsequently, in order to bond the metal-coated woven fabric and the foam on the same surface, a resin of Formulation 3 was applied at a solid content of 5 g / m ² by a floating knife method, and a urethane foam having a phosphorus-based flame retardant (K.K. The outer surface of Everstone DO manufactured by Bridgestone Co., Ltd. is wound so as to be bonded to the resin-laminated surface of Formula 3 of the metal-coated fabric described above,
A gasket for electromagnetic wave shielding was obtained. The performance evaluation results are shown in Table 1. Formulation 8 Crisbon 5116EL 100 parts (Dainippon Ink and Chemicals, Inc., urethane resin, solid content 30%) Ammonium polyphosphate 40 parts (solid content 100%) is added with methyl ethyl ketone to adjust the viscosity to 10,000 cps.

[0022]

Comparative Example 2 The resin of Formulation 1 was applied to one surface of the metal-coated fabric prepared in Example 1 by the floating knife method.
It was coated and dried at 130 ° C. Coating amount is 3g / m ^{2 in} solid content
Met. Next, a resin having the following formulation 9 was applied to the same surface by a floating knife method and dried at 130 ° C.
The coating amount was 140 g / m ² in terms of solid content. It was 44% by weight based on the weight of the metal-coated woven fabric of the phosphorus compound flame retardant used in the obtained metal-coated woven fabric. Furthermore, in order to bond the metal-coated woven fabric and the foam on the same surface, the resin of Formulation 3 was coated at a solid content of 5 g / m ² by a floating knife method, and a urethane foam having a phosphorus-based flame retardant (K.K. The outer surface of Everstone DO manufactured by Bridgestone Co., Ltd. was wound so as to be bonded to the resin-laminated surface of Formula 3 of the metal-coated woven fabric described above to obtain a gasket for electromagnetic wave shielding, and the performance evaluation results are shown in Table 1. Prescription 9 Crisbon 5116EL 100 parts (Dainippon Ink and Chemicals, Inc., urethane resin, solid content 30%) Hexabromocyclododecane 30 parts (solid content 100%) Ammonium polyphosphate 20 parts (solid content 100%) PATOX-M Methyl ethyl ketone is added to 20 parts (manufactured by Nippon Seiko Co., Ltd., antimony trioxide, solid content 100%) to adjust the viscosity to 8000 cps.

Comparative Example 3 The resin of Formulation 1 was applied to one surface of the metal-coated woven fabric used in Example 1 by the floating knife method and dried at 130 ° C. The coating amount was 3 g / m ² in terms of solid content. Next, the resin of the following formulation 2 was applied to the same surface by a floating knife method and dried at 130 ° C. The coating amount was 140 g / m ² in terms of solid content. The proportions of the phosphorus compound flame retardant and the thermally expandable graphite used were 100% by weight and 53% by weight, respectively, with respect to the weight of the metal-coated woven fabric. Furthermore, in order to bond the metal-coated woven fabric and the foam on the same surface, a resin of Formulation 3 was coated at a solid content of 5 g / m ² by a floating knife method, and a urethane foam (Bridgestone Co., Ltd.) to which no flame retardant was added was applied. (Made by Everlight FD)
The outer surface was wound so as to be bonded to the resin-laminated surface of the above-mentioned metal-coated woven fabric formulation 3 to obtain an electromagnetic wave shielding gasket. The performance evaluation results are shown in Table 1.

[0023]

[Table 1]

[0024]

The electromagnetic wave shielding gasket of the present invention has excellent flame retardancy, does not contain antimony which affects the human body, and does not generate toxic halogen-based gas during combustion.

[Brief description of drawings]

FIG. 1 is an example of a schematic view showing a partially cutaway electromagnetic wave shielding gasket according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Resin layer containing flame retardant 2 ... Metal-coated cloth 3 ... Back leak preventing resin layer 4 ... Resin layer 5 containing phosphorus flame retardant and unexpanded thermally expansive graphite -Adhesive resin layer or double-sided adhesive tape 6 ... Flame-retardant foam

Claims (4)

[Claims] 1. A metal-coated cloth in which a resin layer containing at least a phosphorus compound flame retardant and unexpanded thermally expansive graphite is laminated on the outside of a core material made of a flame-retardant synthetic resin foam. A gasket for electromagnetic wave shielding. 2. The electromagnetic wave shield according to claim 1, wherein a resin layer containing a phosphorus compound flame retardant and unexpanded thermally expansive graphite is formed on at least one surface of the metal-coated cloth. gasket. 3. The metal-coated cloth contains 40 to 300% of phosphorus compound flame retardant and 20 to 160% of unexpanded thermally expandable graphite, based on the weight of the metal-coated cloth. The electromagnetic wave shielding gasket according to claim 1 or 2. 4. The gasket for electromagnetic wave shielding according to claim 1, wherein the phosphorus compound flame retardant is ammonium polyphosphate.