Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-12-14
2001-11-13
Hoke, Veronica P. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C442S136000, C442S141000, C442S142000, C442S143000, C442S144000, C442S147000, C524S080000, C524S415000, C524S416000, C524S436000
Reexamination Certificate
active
06316532
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a halogen-free flameproof mesh sheet suitable for being used outdoors such as at a construction work site for a extended period of time, as well as to flame retardant compositions and methods for their manufacture and use.
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 small number of stories. Different types of flameproof mesh sheets are often used in the construction industry for safety and protection. Flameproof mesh sheets such as those useful for houses having a small number of stories and/or sheets used for scattering prevention must be laid in these buildings and regulations of such sheets are becoming more and more strict.
Currently used flameproof mesh sheets are produced by weaving gray yarn prepared by coating a polyester, nylon or polypropylene multi-filament fiber with a vinyl chloride-based paste resin composition and heating the obtained gray cloth. Alternatively, such sheets are made by coating a woven gray fabric prepared from multi-filament fibers with a vinyl chloride-based paste resin composition. The coated fabric is heated and processed to a desired shape.
Typical resin compositions for coating fibers and fabrics comprise a chlorine containing vinyl chloride resin and a chlorine-based flame retardant such as chlorinated paraffin. It is also possible to employ a brominated flame retardant such as decabromodiphenyl oxide or an inorganic flame retardant such as antimony trioxide (known coating compositions are disclosed, for example, in examined Japanese Patent Publication Nos. 52-41786, 53-18065 and 61-9430, as well as Plastics, February, 1991 which are incorporated by reference in their entireties.
Throughout the world, in recent years, limitations on the use of resins and flame retardants containing halogen which generate harmful gases (such as dioxins and bromine dioxins) at the time of combustion have been put into place from the viewpoint of the environmental preservation of the earth.
It has been proposed in Japanese Laid-open Patent Application No. 10-199406 a flame retardant for mesh sheets which comprises ammonium polyphosphate, as well as a flameproof mesh sheet comprising the same. This invention is halogen free and excellent in terms of no increase in viscosity during storage. However, when the mesh sheet is washed and used repeatedly, a tendency toward the elution of ammonium polyphosphate is seen.
SUMMARY OF THE INVENTION
The present invention provides a halogen-free flame retardant for mesh sheets which has at least a reduced tendency to experience the elution of flameproofing agent when it is used repeatedly, as well as to a flameproof mesh sheet comprising the same.
In accordance with the present invention, there is provided a flame retardant composition suitable for mesh sheets comprising 1.5 to 15 parts by weight of red phosphorus, 5 to 50 parts by weight of melamine sulfate, 40 to 150 parts by weight of a metal hydroxide, and a polyolefin-based resin aqueous dispersion having a resin solid content of 25 to 70% by weight, each of said weights being based upon 100 parts by weight of the solid content of said dispersion.
Additional objects, features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects, features and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
The present invention in many embodiments does not contain halogen, does not experience a rise in the viscosity of flameproofing agent during storage and provides an excellent effect that the flameproofing component does not elute even when a treated mesh sheet is washed and used repeatedly.
The polyolefin-based resin aqueous dispersion of the present invention is advantageously at least one selected from (i) an ethylene vinyl acetate copolymer aqueous dispersion having a resin solid content of 25 to 70 weight % and comprising 15 to 95 weight % of vinyl acetate and the balance comprising (or even consisting of) ethylene, (ii) an ethylene vinyl acetate vinyl versatate copolymer aqueous dispersion having a resin solid content of 30 to 70 weight % and comprising 5 to 35 weight % of ethylene, 30 to 70 weight % of vinyl acetate and 25 to 65 weight % of vinyl versatate, and (iii) an ethylene vinyl acetate acrylate copolymer aqueous dispersion having a resin solid content of 40 to 70 weight % and comprising 5 to 30 weight % of ethylene, 30 to 70 weight % of vinyl acetate and 25 to 65 weight % of an acrylate.
A suitable flame retardant composition for mesh sheets can be prepared by blending a polyurethane aqueous dispersion having a solid content of 25 to 70 weight % with polyolefin-based resin in an amount of 10 to 50 weight % in terms of solid content based on 90 to 50 weight % of the solid content of a copolymer aqueous dispersion. The flame retardant composition for mesh sheets according to the present invention preferably includes red phosphorus is micro-capsulated and the metal hydroxide is magnesium hydroxide and/or aluminum hydroxide.
A suitable flame retardant composition for mesh sheets can also be prepared by including an organic phosphate with the flame retardant composition, the organic phosphate preferably being included in an amount of 3 to 30 parts by weight based on 100 parts by weight of the solid content of the aqueous dispersion resin of the flame retardant composition. The organic phosphate is preferably a halogen-free phosphate.
A flameproof mesh sheet woven out of coated yarn can be produced for example, by impregnating and coating multi-filament fibers with a flame retardant for mesh sheets according to the present invention and heating. The multi-filament fibers advantageously have an equivalent single fineness of 3 to 17 denier, a total fineness of 500 to 4,500 denier, a tensile strength of 4 to 10 g/denier and a break elongation of 14 to 45%. A suitable flameproof mesh sheet can be produced by impregnating and coating a mesh sheet fabric woven out of multi-filament fibers with the flame retardant composition and heating. The mesh sheet fabric woven out of multi-filament fibers can be produced if desired by paralleling 2 to 4 synthetic fibers having an equivalent single fineness of 2 to 17 denier, a total fineness of 150 to 2,500 denier, a tensile strength of 6 to 10 g/denier and a break elongation of 14 to 45%; and weaving an imitation gauge with a loom. The mesh length of the fabric is preferably 10 to 140 warps/10cm and 10 to 140 wefts/10 cm.
If desired the mesh sheet can be impregnated and coated with 60 to 350 parts by weight of the flame retardant composition, based on 100 parts by weight of the multi-filament fibers or the mesh sheet fabric woven out of multi-filament fibers.
Any polyolefin based resin aqueous dispersion or mixtures of dispersion can be used in the present invention. An aqueous dispersion of an ethylene vinyl acetate copolymer an aqueous dispersion of an ethylene vinyl acetate vinyl versatate copolymer and an aqueous dispersion of an ethylene vinyl acetate acrylate copolymer can be advantageously used as a base material (i.e., as the olefin-based resin material) in the present invention. This is because a multi-filament fiber and fabric can be fully impregnated with a flame retardant and/or uniformly coated with the flame retardant when such base materials are employed. The use of an aqueous dispersion typically makes impregnation and coating easy.
A suitable ethylene vinyl acetate copolymer used in the present invention is advantageously a copolymer comprising 15 to 95 weight % of vinyl acetate and the balance comprising of ethylene. A suitable aqueous dispersion of t
Kamiya Kuniaki
Nozaki Saiji
Hoke Veronica P.
Nozaki Saiji
Rader & Fishman & Grauer, PLLC
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