Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1998-10-09
2001-06-19
Anthony, Joseph D. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S416000, C524S503000, C524S507000, C524S707000, C523S179000, C523S333000, C523S334000, C526S329500, C525S127000, C252S609000, C252S606000
Reexamination Certificate
active
06248820
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 at a construction site, and in particular to flameproof mesh sheets capable of being used for a long time.
2. Description of Related 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 also been an increase in the number of houses having a relatively small number of stories. There has recently been an increase in the need for flameproof mesh sheets, for example for safety and protection in houses having a small number of stories and also for scattering prevention. Due to these and other factors, flameproof mesh sheets must be laid in these buildings. Further, regulations are becoming more and more strict regarding their use.
Currently used flameproof mesh sheets and scattering prevention flameproof mesh sheets are generally 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. In addition, they can be prepared 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.
An exemplary resin composition for coating a fiber and fabric comprises a vinyl chloride resin containing chlorine as a resin and a chlorine-based flame retardant such as chlorinated paraffin, bromine-based flame retardant such as decabromodiphenyl oxide or an inorganic flame retardant such as antimony trioxide (see, for example, Examined Japanese Patent Publication Nos. 52-41786, 53-18065 and 61-94305, Plastics, February, 1991 which is incorporated herein in its entirety by reference).
In recent years, it has been demanded globally to avoid the use of resins and flame retardants containing elemental halogen which generate 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 phosphate can be kneaded into a polyolefin to prevent corrosion by elemental halogen contained in an elemental halogen-containing compound flame retardant. However, a flame retardant prepared by dispersing red phosphorus and ammonium phosphate in an aqueous dispersion of an ethylene-vinyl acetate copolymer or an aqueous dispersion comprising the aqueous dispersion and an aqueous dispersion of an &agr;-olefin copolymer and/or an aqueous dispersion of a polyurethane was not known at the time of the present invention.
The inventor of the present invention has proposed in Japanese Laid-open Patent Application No. 9-225464 which is incorporated herein by reference in its entirety a halogen-free flame retardant comprising an aqueous dispersion of a polyolefin resin as a flame retardant. This flame retardant has an excellent effect but it has a tendency to increase in viscosity over time during storage.
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 does not experience an increase in viscosity during storage, and a flameproof mesh sheet comprising the same.
In accordance with these and other objects, there is provided claim
1
a flame retardant for mesh sheets comprising red phosphorus in an amount of 1.5 to 15 parts by weight and an ammonium polyphosphate compound in an amount of 10 to 70 parts by weight based on 100 parts by weight of the solid content of an aqueous dispersion of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 95 wt % and a resin solid content of 25 to 75 wt %.
Other objects, advantages and features will become apparent from the following detailed description which follows.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention relates to a flame retardant for mesh sheets comprising red phosphorus in an amount of 1.5 to 15 parts by weight and an ammonium polyphosphate compound in an amount of 10 to 70 parts by weight based on 100 parts by weight of the solid content of an aqueous dispersion of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 95 wt % and a resin solid content of 25 to 75 wt %.
The flame retardant for mesh sheets can be prepared for example, by mixing an aqueous dispersion of an &agr;-olefin copolymer preferably having a solid content of 20 to 45 wt % with an aqueous dispersion of an ethylene-vinyl acetate copolymer preferably having a vinyl acetate content of 10 to 95 wt % and a resin solid content of 25 to 75 wt % in a solid content weight ratio preferably of 10:90 to 70:30 and adding red phosphorus preferably in an amount of 1.5 to 15 parts by weight and an ammonium polyphosphate compound preferably in an amount of 10 to 70 parts by weight based on 100 parts by weight of the total resin solid content.
The flame retardant for mesh sheets can also be prepared alternatively, for example, by mixing an aqueous dispersion of a polyurethane preferably having a solid content of 25 to 70 wt % with an aqueous dispersion of an ethylene-vinyl acetate copolymer preferably having a vinyl acetate content of 10 to 95 wt % and a resin solid content of 25 to 75 wt % in a solid content weight ratio preferably of 10:90 to 90:10 and adding red phosphorus in an amount of preferably 1.5 to 15 parts by weight and an ammonium polyphosphate compound preferably in an amount of 10 to 70 parts by weight based on 100 parts by weight of the total resin solid content.
The flame retardant for mesh sheets can also further be prepared by mixing an aqueous dispersion of an &agr;-olefin copolymer preferably having a solid content of 20 to 45 wt % and an aqueous dispersion of a polyurethane preferably having a solid content of 25 to 70 wt % with an aqueous dispersion of an ethylene-vinyl acetate copolymer preferably having a vinyl acetate content of 10 to 95 wt % and a resin solid content of 25 to 75 wt % in a solid content weight ratio of preferably 10:10:80 to 50:80:10 and adding red phosphorus preferably in an amount of 1.5 to 5 parts by weight and an ammonium polyphosphate compound preferably in an amount of 10 to 70 parts by weight based on 100 parts by weight of the total resin solid content. The red phosphorus, and/or the ammonium phosphate compound can be micro-capsulated if desired.
Optionally, the flame retardant for mesh sheets prepared by also mixing a metal hydroxide in an amount preferably of 60 to 150 parts by weight based on 100 parts by weight of the solid content of the aqueous dispersion resin of the flame retardant for mesh sheets as described above. The metal hydroxide can expediently be magnesium hydroxide and/or aluminum hydroxide.
The flame retardant can be used, for example, to impregnate flameproof mesh sheets woven out of coated yarn which are then heated. The flameproof mesh sheets can comprise a multi-filament fiber that preferably has an equivalent single fineness of 3 to 17 denier, a total fineness of 1,000 to 4,500 denier, a tensile strength of 6 to 10 g/denier and break strength of 14 to 45%. The flameproof mesh sheets can be prepared for example by impregnating a mesh sheet fabric woven out of multi-filament fibers with the flame retardant for mesh sheets and heating. The mesh sheet fabric can be woven out of multi-filament fibers and can compose a mesh sheet fabric that is prepared for example by paralleling 1 to 4 synthetic fibers preferably having an equivalent single fineness of 2 to 13 denier, a total fineness of 150 to 2,500 denier, a tensile strength of 6 to 10 g/denier and a break strength of 14 to 45% and leno weaving them with a weaving machine. The fabric can advantageously have a mesh length of 10 to 140 warps/10 cm and 10 to 140 wefts/10 cm. The amount of the flame retardant for mesh s
Kamiya Kuniaki
Nozaki Saiji
Anthony Joseph D.
Kyowa Kabushikikaisha
Rader & Fishman & Grauer, PLLC
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