JP2003247164A - Flame-retardant metal-coated fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a metal-coated fabric which has excellent flame retardance and electromagnetic wave shielding properties, does not generate harmful halogen gas in combustion and does not contain antimony harmful to the human body. <P>SOLUTION: The metal-coated fabric having excellent flame retardance is obtained by using at least a phosphorus-based compound flame retardant as a flame retardant except a halogen-based flame retardant, an antimony-based flame retardant and a flame retardant composed of a phosphorus allotrope such as red phosphorus, etc., and unexpanded thermally expandable graphite and has a resin layer kneaded with the flame retardant laminated to at least one side of the fabric. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant metal-coated cloth used as an electromagnetic wave shielding material for electronic devices and the like, which does not generate a toxic halogen-based gas during combustion, The present invention relates to a flame-retardant metal-coated cloth that does not contain the influence antimony.

In recent years, with the spread of not only home electric appliances but also various information terminals such as personal computers, mobile phones, video games, etc., electromagnetic waves leaking from these devices cause malfunction of other electronic devices and influence on users. Is afraid. 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), these electromagnetic wave shielding materials are also required to have flame retardant performance, and among them, those satisfying the flame retardancy of FMVSS standard and UL standard are required. Is coming. As one of these electromagnetic wave shield materials, there is a material in which a metal coating is formed on a fiber cloth, but in many cases, the coated metal serves as an oxidation catalyst to increase flammability. That is, it is considered that the metal coating not only prevents the fire extinguishing action due to the melting of the fiber cloth, but also improves the thermal conductivity due to the formed metal coating and promotes the spread of fire. Various studies have been conducted to improve the flame retardancy of such materials.

For example, Japanese Patent Application Laid-Open No. 62-21870 discloses a method of imparting flame retardancy by adding a phosphorus compound type flame retardant and a halogen compound type flame retardant to a metal-adhered cloth. However, in recent years, the relationship between halogen compounds and dioxins has attracted attention, and the structure of halogen-based flame retardants is too similar to that of dioxins, and halogenated organic compounds such as Cu and Fe at temperatures of 300 to 600 ° C. Combustion with metallic elements may produce compounds such as dioxins, 800 ° C for complete combustion
It is said that dioxin is generated when the temperature is lowered again even if the above-mentioned combustion decomposition is carried out, and the use of the halogen-based flame retardant is not preferable from the viewpoint of environmental pollution.

Further, Japanese Patent Application Laid-Open No. 7-42079 discloses that
There is described a woven fabric coated with a metal and having an electromagnetic wave shielding property using an organic compound-based flameproofing agent such as an organic phosphorus compound and an inorganic compound-based flameproofing aid such as an antimony compound. However, using antimony compounds,
There is concern about the effects of antimony on the human body, which is not desirable.

[0005]

The present invention has been made in view of the above circumstances, and its purpose is to prevent generation of harmful dioxin, phosphine gas, etc. during combustion, and antimony which is harmful to the human body. Is to obtain a metal-coated cloth having excellent flame retardancy without using.

[0006]

Means for Solving the Problems The present invention has been made as a result of intensive studies for solving the above problems, and solved the above problems by using a phosphorus compound flame retardant and unexpanded thermally expansive graphite. And has the following configuration. That is, the present invention is firstly a metal-coated cloth comprising at least one surface of the cloth provided with a resin layer containing at least a phosphorus compound flame retardant and unexpanded thermally expansive graphite. Secondly, with respect to the weight of the metal-coated cloth,
The metal-coated cloth according to the first aspect is characterized in that it contains 40 to 300% of a phosphorus compound flame retardant and 20 to 160% of unexpanded thermally expansive graphite. Thirdly, there is provided the metal-coated cloth according to the first or second aspect, wherein the phosphorus compound flame retardant is ammonium polyphosphate.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The form of the fabric used in the present invention is
Examples thereof include woven fabric, knitted fabric, and non-woven fabric, and are not particularly limited. In addition, the fiber materials used are synthetic fibers 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. However, polyester fibers are preferable in view of processability and durability.

As a method for forming the metal coating, a conventionally known method can be used. For example, in order to ensure the fixing of the applied metal to the fabric made of the above fibers, impurities such as sizing agents, oil agents, dust, etc. that have adhered to the surface of the fibers in advance are completely removed by scouring treatment. Preferably. A conventionally known method is used for the scouring treatment and is not particularly limited. A metal coating can be formed on a scoured cloth by vapor deposition, sputtering, electroplating, electroless plating, etc. However, electroless plating is required from the viewpoint of uniformity of the formed metal coating and productivity. Or a combination of the electroless plating method and the electroplating method is preferably used.
Examples of the metal used include gold, silver, copper, zinc, nickel, and alloys thereof, but copper and nickel are preferable in consideration of conductivity and manufacturing cost. The coating layer formed of these metals is preferably one layer or two layers. If the number of layers is 3 or more, the metal coating layer becomes thicker,
The conductive woven fabric may become hard and the processing cost may increase. 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 set as appropriate in consideration of the required shielding property and durability.

In the product of the present invention, a resin layer containing a flame retardant is laminated on the fibers on which these metal coatings are formed. The resin to be laminated is preferably a synthetic resin, such as urethane resin, acrylic resin or ester resin. Etc. Among them, urethane resin is preferable because it is easy to obtain flame retardancy and is excellent in friction strength and flexibility. The amount of the resin containing the flame retardant 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, it is difficult to sufficiently add the flame retardant, and if it is too much, the texture becomes hard and it is also economically disadvantageous. The resin application method is
There are coating methods such as a floating method, a knife coater method, and a roll coater method, and any method may be used.

The viscosity of the resin containing the flame retardant is 2000 to 30.
The range of 000 cps is preferable, and more preferably 400
The range of 0 to 15000 cps is preferable. Viscosity is 200
If it is lower than 0 cps, the resin may leak back to the opposite surface of the cloth, resin unevenness may occur, and the appearance quality may be impaired.
If the viscosity is higher than 30,000 cps, the coatability will be poor.

In order to prevent the resin from leaking back to the opposite surface of the cloth, a resin layer may be previously formed on the same surface before the resin containing the flame retardant is applied. The resin is preferably an acrylic resin from the viewpoint of processability, flexibility and economy, and has a viscosity of 20.
00 to 30,000 cps, more preferably 10,000 to
It is in the range of 15000 cps. If it is lower than 2000 cps, the resin may leak back to the opposite side of the cloth and spoil the appearance, and if higher than 30,000 cps, the coatability is deteriorated. The coating amount is 1 to 10 g / m ² , preferably 3 to 7 g /
It is in the range of m ² . If it is less than 1 g / m ^2, the back leakage prevention effect of the resin containing the flame retardant to be laminated next cannot be sufficiently achieved, and if it is more than 10 g / m ² , flame retardancy may be impaired. Floating method and knife coater method,
There is a coating method such as a roll coater method, and any method may be used.

As the flame retardant used in the present invention, at least a phosphorus compound flame retardant and unexpanded thermally expansive graphite are used.
Phosphorus compounds flame retardants include bisphenol A bis (diphenyl phosphate) and resorcinol bis (di 2,6
-Xylyl) phosphate, etc.,
Examples thereof include phosphoric acid amides such as triphenylphosphamide and ammonium polyphosphates, and ammonium polyphosphates are particularly preferably used because they have a high phosphorus content and an excellent flame retarding effect. Phosphorus allotropes such as red phosphorus have a flame-retardant effect, but are not preferable because they are highly toxic or generate toxic gas such as phosphine gas when burned. Further, since ammonium polyphosphate alone has poor moisture resistance, it may decompose if left in a high-humidity environment for a long time to impair flame retardancy. Therefore, it is preferable to use a type in which the surface is coated with a melamine resin because decomposition and deterioration can be suppressed. 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 diffusion of the combustible compound generated inside the fiber. As the heat-expandable graphite that can be used, natural graphite, pyrolytic graphite, quiche graphite and the like inorganic acid (concentrated sulfuric acid,
Examples include acid-treated with a mixed solution of nitric acid) and a strong oxidizer (perchloric acid, perchlorate, hydrogen peroxide solution, etc.). 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 (sodium, potassium, magnesium, calcium, It is also possible to use those which have been neutralized with hydroxides such as barium, 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 diameter of the unexpanded thermally expandable graphite is preferably 10 to 1000 μm. Particle size is 1
If it is less than 0 μm, the expansion coefficient of graphite is small, and as a result, the flame retardancy may decrease. If it is more than 1000 μm, the expansion coefficient of graphite is large and good in flame retardance. In addition, the dispersibility becomes poor, and the quality of the resin coated surface is also affected. The phosphorus compound flame retardant and the unexpanded thermally expansive graphite may be mixed and dispersed in the resin, or each flame retardant may be dispersed and mixed in the resin. The ratio to the resin is a solid content ratio, the phosphorus compound flame retardant is 120 to 190%, and the unexpanded thermally expansive graphite is 6%.
It is in the range of 0 to 100%. If the ratio is higher than this, the resin coating becomes brittle, and if the ratio is low, sufficient flame retardancy may not be obtained. Also, with respect to the weight of the metal-coated cloth,
The phosphorus compound flame retardant is 40 to 300%, preferably 70.
~ 190%, 20-160% of unexpanded thermally expansive graphite,
It is preferably in the range of 35 to 100%. If it is less than these ratios, there is a possibility that a sufficient flame retardant may not be obtained, and if it is more than these ratios, further improvement in flame retardancy may not be expected, and there is a risk that costs may increase. As described above, the present invention essentially requires a phosphorus-based compound flame retardant and unexpanded thermally expansive graphite, and further comprises a halogen-based flame retardant, an antimony-based flame retardant, or an allotrope of phosphorus. It is also possible to use a flame retardant other than the flame retardant, such as magnesium hydroxide or a hydrated metal compound such as aluminum hydroxide.

Further, the resin layer containing the flame retardant may be formed not only on one surface of the cloth but also on both surfaces thereof. That is, it is also possible to laminate the resin containing the flame retardant as described above on one surface and then laminate the resin containing the same flame retardant 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.

[0014]

[Examples] Fabric evaluation methods in Examples and Comparative Examples are as follows. 1. Flame retardance evaluation FMVSS 302 method and UL94 VTM-1 are used for evaluation. 2. 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 / □. 3. 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.

[0015]

Example 1 Polyester fiber woven fabric (warp 56 dtex /
24f, weft 56 dtex / 36f) is scoured, dried and heat treated, and subsequently contains palladium chloride 0.3 g / L, stannous chloride 30 g / L, 36% hydrochloric acid 300 ml / L 4
It was immersed in a 0 ° C. aqueous solution for 2 minutes and then washed with water. Then, it was immersed in borofluoric acid having an acid concentration of 0.1 N at 30 ° C. for 5 minutes and then washed with water. Next, copper sulfate 7.5 g / L, 37% formalin 3
It was immersed in an electroless copper plating solution consisting of 0 ml / L and Rochelle salt 85 g / L at 30 ° C. for 5 minutes and then washed with water. Subsequently, nickel sulfamate 300 g / L, boric acid 30 g / L
L, nickel chloride 15 g / L, pH 3.7 electroplating nickel plating solution at 35 ° C. for 10 minutes, current density 5 A / dm ²
After immersing in, nickel was laminated and washed with water. Copper 10 g / m ² in the fabric, the nickel is 4g / m ² Plating. The obtained conductive woven fabric had a weight of 64 g / m ² . In order to prevent back leakage of the resin to the back surface of the obtained metal-coated woven fabric, a resin having the following formulation 1 was applied by a floating knife method and dried at 130 ° C. for 1 minute. The coating amount was 4 g / m ² in terms of solid content. Next, the resin of Formulation 2 was applied to the same surface by a knife-on-roll method, and dried at 130 ° C. for 2 minutes. The coating amount was 140 g / m ² in terms of solid content. In the obtained metal-coated woven fabric, 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. 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.

[0016]

Example 2 The resin of Formula 3 was applied to the surface of the flame-retardant metal-coated woven fabric obtained in Example 1 on which the resin was laminated, by a floating knife method, and dried at 130 ° C. for 1 minute. The coating amount was 5 g / m ² in terms of solid content. In the obtained metal-coated fabric, the proportions of the phosphorus compound flame retardant and the thermally expandable graphite used were 102% by weight and 53% by weight, respectively, with respect to the weight of the metal-coated fabric. The performance evaluation results are shown in Table 1. Formulation 3 Toacron SA-6218 100 parts (made by Tope Co., acrylic resin, solid content 18%) Nonnen R0111-4 10 parts (Maruhishi Yuka Kogyo Co., Ltd., phosphoric acid ester compound, solid content 100%)

[0017]

Example 3 On one surface 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. for 1 minute. The coating amount was 4 g / m ² in terms of solid content. Furthermore, the resin of Formula 4 is applied on the same surface by a knife-on-roll method,
It was dried at 130 ° C. for 2 minutes. Solid coating amount is 150g
Was / m ² . In the obtained metal-coated woven fabric, the proportions of the phosphorus compound flame retardant and the thermally expandable graphite used were 113% by weight and 61% by weight, respectively, with respect to the weight of the metal-coated fabric. The performance evaluation results are shown in Table 1. Prescription 4 Crisbon 5116EL 100 parts (Dainippon Ink and Chemicals, Inc., urethane resin, solid content 30%) Nonnen R0111-455 parts (Maruhishi Yuka Kogyo Co., Ltd., phosphate compound, solid content 100%) ) Methyl ethyl ketone is added to 30 parts (solid content 100%) of thermally expansive graphite to adjust the viscosity to 7500 cps.

[0018]

Comparative Example 1 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. for 1 minute. The coating amount was 4 g / m ² in terms of solid content. Furthermore, the resin of Formulation 5 was applied to the same surface by a knife-on-roll method, and dried at 130 ° C. for 2 minutes. The coating amount is 14 solids
It was 0 g / m ² . In the obtained metal-coated woven fabric, the ratio of the phosphorus compound flame retardant used to the weight of the metal-coated woven fabric was 80% by weight. Table 1 shows the performance evaluation results
Shown in. Formulation 5 Crisbon 5116EL 100 parts (manufactured by 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 8000 cps.

[0019]

Comparative Example 2 On one surface 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. for 1 minute. The coating amount was 4 g / m ² in terms of solid content. Further, the resin of Formulation 6 was coated on the same surface by a knife-on-roll method, and dried at 130 ° C. for 2 minutes. The coating amount is 14 solids
It was 0 g / m ² . In the obtained metal-coated woven fabric, the ratio of the phosphorus compound flame retardant used to the weight of the metal-coated woven fabric was 44% by weight. Table 1 shows the performance evaluation results
Shown in. Prescription 6 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) to adjust the viscosity to 8000 cps.

[0020]

[Table 1]

[0021]

Industrial Applicability The metal-coated fabric 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 upon combustion.

[Brief description of drawings]

FIG. 1 is an example of a schematic cross-sectional view of a metal-coated cloth according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Resin layer having a flame retardant 2 ... Metal-coated cloth 3 ... Back leakage prevention resin layer 4 ... Resin layer having a phosphorus compound flame retardant and unexpanded thermally expansive graphite

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4L031 AA18 AA25 AB31 BA02 BA04                       BA18 CB12 DA17                 4L033 AA07 AA10 AB04 AC05 AC15                       CA50                 5E321 BB21 BB23 BB41 BB44 BB60                       GG05

Claims (3)

[Claims] 1. A metal-coated cloth having a resin layer having at least one phosphorus compound flame retardant and unexpanded thermally expansive graphite on at least one surface of the cloth. 2. Phosphorus-based compound flame retardant is 40 to 300%, and unexpanded thermally expandable graphite is 2% by weight of the metal-coated cloth.
The metal-coated fabric according to claim 1, wherein the metal-coated fabric contains 0 to 160%. 3. The metal-coated cloth according to claim 1, wherein the phosphorus compound flame retardant is ammonium polyphosphate.