Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Scrim – Woven scrim
Reexamination Certificate
2001-05-21
2002-05-07
Cameron, Erma (Department: 1762)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Scrim
Woven scrim
C442S043000, C427S393300
Reexamination Certificate
active
06383957
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a halogen-free flameproof mesh sheet used outdoors such as a construction site for a long time.
2. Prior Art
In recent years, there has been a trend toward the construction of buildings having a large number of stories in the construction industry. Meanwhile, there has been an increase in the number of houses having a small number of stories. Flameproof mesh sheets for safety and protection and scattering prevention flameproof mesh sheets must be laid in these buildings and regulations are becoming more and more strict.
Currently, used flameproof mesh sheets and scattering prevention flameproof mesh sheets are produced by weaving yarn prepared by coating a polyester, nylon or polypropylene multi-filament fiber with a vinyl chloride-based paste resin composition and heating and then heating the obtained cloth and by coating a fabric prepared by weaving and processing a multi-filament fiber with a vinyl chloride-based paste resin composition, heating and processing to a desired shape, respectively.
A vinyl chloride containing chlorine is used as the resin composition for coating a fiber and fabric. Illustrative examples of the flame retardant include chlorine-based flame retardants such as chlorinated paraffin, bromine-based flame retardants such as decabromodiphenyl oxide, and inorganic flame retardants such as antimony trioxide (Examined Japanese Patent Publication Nos. 52-41786, 53-18065 and 61-94305, Plastics, February, 1991).
In recent years, it has been globally demanded to avoid the use of resins and flame retardants containing elemental halogen which generates harmful gas at the time of combustion from the viewpoint of the environmental preservation of the earth.
Japanese Laid-open Patent Application No. 61-223045 proposes that red phosphorus and ammonium polyphosphate are kneaded into polyolefin to prevent corrosion by halogen contained in a halogen-containing compound flame retardant. However, there is unknown a flame retardant which is dispersed in an aqueous dispersion of a polyolefin resin.
SUMMARY OF THE INVENTION
In view of the above situation, it is an object of the present invention to provide a flame retardant for halogen-free flameproof mesh sheets which does not generate harmful halogen gas at the time of combustion and a flameproof mesh sheet comprising the same.
The present invention relates to:
A flame retardant for mesh sheets comprising about 1.5 to 15 parts by weight of red phosphorus and about 10 to 70 parts by weight of an ammonium polyphosphate compound based on 100 parts by weight of a solid content of an aqueous dispersion of a polyolefin resin having a resin solid content of about 20 to 45 wt %.
The polyolefin resin of the aqueous dispersion of a polyolefin resin may be selected from ethylene-methacrylic acid metal ion crosslinked copolymers and ethylene-based &agr;-olefin copolymers.
The polyolefin resin of the aqueous dispersion of a polyolefin resin may be a mixture of about 90 to 10 wt % of an ethylene-methacrylic acid metal ion crosslinked copolymer and about 10 to 90 wt % of an ethylene-based &agr;-olefin copolymer.
The red phosphorus and ammonium polyphosphate can be micro-encapsulated.
The flame retardant can further comprises about 60 to 150 parts by weight of a metal hydroxide based on 100 parts by weight of the solid content of the aqueous dispersion of a polyolefin resin. The metal hydroxide can be magnesium hydroxide and/or aluminum hydroxide.
The flameproof mesh sheet can be prepared by impregnating with the flame retardant, heating, and woven.
The flameproof mesh sheet can have an equivalent single fineness of a multi-filament fiber of about 3 to 17 denier, a total fineness of about 1,000 to 4,500 denier, a tensile strength of about 6 to 10 g/denier and a break strength of about 14 to 45%.
The flameproof mesh sheet can be coated by impregnating a mesh sheet fabric woven of a multi-filament fiber with the flame retardant for mesh sheets and heated.
The flameproof mesh sheet can be prepared by paralleling 1 to 4 synthetic fibers having an equivalent single fineness of about 2 to 13 denier, a total fineness of about 150 to 2,500 denier, a tensile strength of about 6 to 10 g/denier and a break strength of about 14 to 45% and leno weaving with a weaving machine and has a mesh length of about 10 to 140 warps/10 cm and about 10 to 140 wefts/10 cm.
The flameproof mesh sheet may be used in an amount of about 60 to 350 parts by weight based on 100 parts by weight of the multi-filament fiber or the mesh sheet fabric woven of the multi-filament fiber to coat the mesh sheet fabric by impregnation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An aqueous dispersion of a polyolefin resin is used as a base material in the present invention because a multi-filament fiber and fabric are fully impregnated with a flame retardant and uniformly coated with the flame retardant.
Preferable, the aqueous dispersion of a polyolefin resin comprises as the polyolefin resin an ethylene-methacrylic acid metal ion crosslinked copolymer containing about 10 to 20 wt % of methacrylic acid and can have a solid content of about 20 to 45 wt %, a particle diameter of about 0.01 to 3 &mgr;m, a pH of 8 to 11, a viscosity of about 30 to 1,000 cp (a BM type viscometer, 6 rotations). The polyolefin resin is particularly preferably an ethylene-methacrylic acid metal ion crosslinked copolymer and can have a resin surface hardness of about D-40 to 75 (Shore-D: ASTMD2240) such as an ionomer resin exemplified by S-300, S-650 or S-100 (of Mitsui Petrochemical Industry Co.).
An ethylene-based &agr;-olefin copolymer may be used and a dispersion thereof has a solid content of about 20 to 45 wt %, a particle diameter of about 1 to 10 &mgr;m, a pH of about 8 to 11, a viscosity of about 2,000 to 8,000 cp (a BM type viscometer, 6 rotations) and a resin surface hardness of about A-80 to 97 (Shore A: ASTMD). The ethylene-based &agr;-olefin copolymer is preferably a thermoplastic elastomer resin comprising about 50 wt % or more of ethylene, such as A-100 or A-200 (of Mitsui Petrochemical Industry Co.).
When a mixture of about 90 to 10 wt % of an ethylene-methacrylic acid metal ion crosslinked copolymer and about 10 to 90 wt % of an ethylene-based &agr;-olefin copolymer is used, the surface hardness of the ethylene-methacrylic acid metal ion crosslinked copolymer having a higher surface hardness and the surface hardness of the ethylene-based &agr;-olefin copolymer having a lower surface hardness are well balanced and the feeling of a conventional flameproof mesh sheet produced from a soft vinyl chloride resin is obtained. As for the preferable ratio of the two materials, the ethylene-methacrylic acid metal ion crosslinked copolymer may be used in a proportion of about 80 to 40 wt % and the ethylene-based &agr;-olefin in copolymer in a proportion of about 20 to 60 wt %.
Red phosphorus used in the present invention may be preferably micro-encapsulated. Use of the micro-encapsulated red phosphorus makes it possible to reduce an increase in the viscosity of an aqueous dispersion when red phosphorus is mixed into the olefin aqueous dispersion. Further, the flameproof mesh sheet is detached and washed to remove dirt after it is spread at a construction site and used for 4 to 8 months. It is washed by immersing it in hot water heated at about 40° C. and containing a detergent for several hours. At this point, red phosphorus can be prevented from dissolving in water by micro-encapsulation. The concentration of red phosphorus is about 75 to 95% and the average particle diameter thereof is about 10 to 40 &mgr;m.
Micro-encapsulation can be suitably carried out by coating the surface of a red phosphorus particle with a resin or inorganic material by interfacial polymerization, coacervation or the like.
The ammonium polyphosphate compound used in the present invention may be ammonium polyphosphate or amide polyphosphate. Use of the micro-encapsulated ammonium polyphosphate compound makes it possible to reduce an inc
Kamiya Kuniaki
Nozaki Saiji
Cameron Erma
Kyowa Kabushiki Kaisha
Rader & Fishman & Grauer, PLLC
LandOfFree
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