Title of Invention

DISASTER-PROOF MESH SHEET

Abstract

[OBJECT] To provide a disaster-proof mesh sheet which shows neither change in shape nor discoloration after aging and excels in flame retardancy. [MEANS OF FULFILLMENT] A disaster-proof mesh sheet produced by preparing a coated yarn by coating a multifilament yarn with a polyvinyl chloride type paste sol composition, weaving the coated yarn, and finishing the weave is characterized in that a. the multifilament yarn is synthetic fibers having a monofilament size in the range of 3 -17 deniers, a total size in the range of 1000 -4500 deniers, a tensile strength in the range of 6.5 -105 g/denier, and an elongation at rupture in the range of 14 -45% and b. the polyvinyl chloride type paste sol composition is a paste sol composition containing 100 parts by weight of a polyvinyl chloride type paste, 30 -85 parts by weight of a phthalic ester type plasticizer, 3 -30 parts by weight of a phosphoric ester type plasticizer, and 5 -45 parts by weight of an inorganic flame retardant.

Full Text

[Field of the Invention] This invention relates to a disaster proof mesh sheet to be used for a long time outdoors at a site of building construction or a site of civil engineering. [0002] [Prior Art] In recent years, the building industry is tending toward constructing buildings of increasingly greater heights. The constructor of such a tall building is under obligation, for the sake of ensuring personal safety, to enclose the building or a site thereof by pitching disaster-proof sheets and disaster-proof mesh sheets. The regulations concerning this measure for safety are all the more gaining in strictness. The disaster-proof mesh sheets which are currently in use are products obtained by weaving natural fibers or synthetic fibers such as nylon or polyester, coating the resultant crude weave with a vinyl chloride type paste resin composition, and forming the coated weave in a prescribed shape. The disaster-proof mesh sheets by nature are required to excel in tensile strength, falling dart impact strength, disaster preventing property, weatherability (discoloration), pollution-proofing property, wind load, and dimensional stability. It has been heretofore known to obtain a self-sustaining reticular structure by a technique which comprises forming a reticular structure with a coated yarn having a core yarn coated with a foaming agent-containing vinyl chloride type paste resin sol (plastisol) and heat-treating the reticular structure at a temperature for fusing the crossed parts of the yarn and, at the same time, effervescing the foaming agent under the condition for flattening the coated yarn (as disclosed in US Patent No. 4,144,371, for example). This proposal has absolutely no mention of the impartation of flame-retardancy and has no specific disclosure of the plasticizer to be used in the plastisol. The idea of jointly using chlorinated paraffin, phosphorus type organic compound, and antimony trichloride for improving the flame retardancy of the plasticizing resin is introduced as prior art in JP-B-52-41,786 and JP-B-53-18,065. [0003] Recently, the sites of building construction have been required to improve their environments and beautify their outward appearances. As a result, the colors of the disaster-proof mesh sheets have been abundantly diversified in kind and the sites of building construction have become colorful owing to the use of the disaster-proof mesh sheets of varying colors. Meanwhile, when the colors of the disaster-proof mesh sheets are faded by deterioration of weatherability, they assume colors of defiled tones different from their initial colors. The fact that these dirty colors have an adverse effect on the environments has come to pose a problem. After the disaster-proof mesh sheets have been used at the sites of building construction, they are laundered and then put to reuse. When they are reused, they are more often than not pitched together with new mesh sheets at one and the same site of building construction. In this case, the problem arises that the new mesh sheets and the laundered mesh sheets differ in color and the uneven distribution of colors impairs the outward appearance of the site of building construction. This problem demands a solution. Together with this problem in the aspect of environment, the effect of imparting improved flame retardancy to the disaster- proof mesh sheet has not yet been fully satisfied. The idea of using a plasticizer which is composed of three components, i.e. a ophthalmic ester type plasticizer, a phosphoric ester type plasticizer, and a halogen-containing type plasticizer, is proposed in JP-B-61-9,430. The mesh sheet which embodies this idea has an outstanding effect and finds extensive utility. From the viewpoint of the recent problem of discoloration, the halogen-containing type plasticizer is rapidly deteriorated by the action of light, for example, and the compound plasticizer incurs discoloration and heavy degradation of strength, particularly the falling dart impact strength. The present inventor"s study has confirmed that it is proper to decrease the amount of the halogen-containing type plasticizer to the fullest possible extent and it is ideal to avoid the use of this plasticizer completely. The amount of the phosphoric ester type plasticizer to be used is preferred to be small. The halogen-containing type plasticizer poses the problem of discoloration. Further, the use of this plasticizer in an unduly large amount entails the disadvantage that the disaster-proof mesh sheets assume a sticky surface and tend to gather dirt while in use at the site of building construction and permit no easy laundering. In terms of the resistance to staining, the amount of the halogen-containing type plasticizer is preferred to be small. Further, in terms of safety, the disaster-proof mesh sheets are earnestly required to possess high strength, manifest large and lasting falling dart impact strength, and suffer only sparing decrease in the falling dart impact strength. The prior art has incurred difficulty in solving these problematic points. [0004] [Problem to be Solved by the Invention] This invention has issued from the realization of such true state of prior art and is aimed at providing a disaster-proof mesh sheet which succumbs only sparingly to deterioration by the solar light, suffers only slight discoloration, incurs only small decrease in strength, particularly the falling dart impact strength, and excels in resistance to staining. [0005] [Means for Solving the Problem] This invention concerns: "1. A disaster-proof mesh sheet produced by preparing a coated yarn by coating a multifilament yarn with a polyvinyl chloride type paste sol composition, weaving the coated yarn, and finishing the weave, characterized in that a. the multifilament yarn is synthetic fibers having a monofilament size in the range of 3 - 17 deniers, a total size in the range of 1000 - 4500 deniers, a tensile strength in the range of 6.5 - 10^ g/denier, and an elongation at rupture in the range of 14 - 45% and b. the polyvinyl chloride type paste sol composition is a paste sol composition containing a polyvinyl chloride type paste sol 100 parts by weight a phthalic ester type plasticizer 30 - 85 parts by weight a phosphoric ester type plasticizer 3-30 parts by weight and an inorganic flame retardant 5-45 parts by weight. "2. A disaster-proof mesh sheet according to Item 1, wherein the gravimetric ratio of the multifilament yarn to the polyvinyl chloride type paste sol composition is such that the polyvinyl chloride type paste sol amounts to 110 - 350 parts by weight per 100 parts by weight of the multifilament yarn. "3. A disaster-proof mesh sheet according to Item 1 or Item 2, wherein the multifilament yarn is the fibers selected from among polyester fibers, nylon fibers, polypropylene fibers, and vinylon fibers. "4. A disaster-proof mesh sheet according to any of Items 1 to 3, wherein the polyvinyl chloride type paste resin has a vinyl chloride content of not less than 90% and an average polymerization degree in the range of 750 - 2000. "5. A disaster-proof mesh sheet according to any of Items 1 to 4, wherein the plasticizers incorporate therein 1-8 parts by weight of an epoxy type plasticizer based on 100 parts by weight thereof.. "6. A disaster-proof mesh sheet according to any of Items 1 to 5, wherein the plasticizers do not contain a halogen-containing plasticizer. "7. A disaster-proof mesh sheet according to any of Items 1 to 6, wherein the woven disaster-proof mesh sheet is finished by a heat treatment." [0006] [Mode of Embodiment of the Invention] The multifilament yarn to be used in this invention is at least one member selected from the group consisting of polyester, nylon, polypropylene, and vinylon. In terms of strength and thermal shrinkage, the multifilament yarn of polyester fibers proves particularly advantageous among other fibers. [0007] The disaster-proof mesh sheet is enabled to acquire high strength and enjoy small weight by imparting to the multifilament yarn a tensile strength in the range of 6.5 - 10.5 g/denier. It is enabled to manifest high toughness and excel in the ability to absorb the energy of impact in the course of fall by imparting an elongation at rupture in the range of 14 - 40%. The monofilament size of the multifilament yarn is in the range of 3 - 17 deniers, preferably 3-12 deniers, and particularly preferably 4-9 deniers and the total size thereof is in the range of 1000 - 4500_ deniers, preferably 1260 - 3500 deniers, and particularly preferably 2350 - 3000 deniers. [0008] The coating of the multifilament yarn with a polyvinyl chloride type paste sol composition is attained by passing the yarn through a sizing nozzle. If the monofilament size in this case is less than 3 deniers, no smooth yarn coating will be obtained because the monofilaments are suffered to raise fluffs, the coating proceeds unevenly, and the coated yarn is undulated. Even the possibility that the yarn waste resulting from fluffing clogs the sizing nozzle to the extent of interfering with the coating operation may ensue. If the monofilament size exceeds 17 deniers, the multifilament yarn, though enjoying ample tensile strength, will suffer deficiency in the falling dart impact strength, the most important of all the requirements, and fail to acquire a large falling dart impact strength proportionate to the tensile strength. Further, if the monofilament size exceeds 17 deniers, the disaster-proof mesh sheet obtained by weaving the coated multifilament yarn and finishing the resultant weave will produce rigid tactile sensation and allow no easy handling. [0009] If the total filament size is not more than 1,000 deniers, the produced disaster-proof mesh sheet will not easily acquire large falling dart impact strength. If the number of yarns is increased for the purpose of exalting the falling dart impact strength, the disaster-proof mesh sheet will be at a disadvantage in acquiring unduly low mesh density, allowing no smooth passage of air, and suffering from unduly large wind load. If the total filament size exceeds 4,500 deniers, the disaster-proof mesh sheet obtained by weaving the coated yarns and finishing the resultant weave will be at a disadvantage in weighing excessively and allowing no easy handling while the sheet is being pitched. The fact that the monofilament size is in the range of 3 -17 deniers and the total filament size in the range of 1000 -4500 deniers, preferably 1260 - 3500 deniers, and particularly preferably 2450 - 3000 deniers is important for the disaster-proof mesh sheet. To withstand the falling impact, the tensile strength must be in the range of 6.5 - 10^ g/denier and the elongation at rupture in the range of 14 - 45%. [0010] If the tensile strength is not more than 6.5 g/denier, the disaster-proof mesh sheet will be at a disadvantage in assuming unduly low strength and failing to acquire large falling dart impact strength. If the tensile strength exceeds 10^ g/denier, the yarn will be deficient in elongation at rupture and the disaster-proof mesh sheet will be deficient in falling dart impact strength. The tensile strength, therefore, must be in the range of 6^ g - 10^ g/denier. If the elongation at rupture is not more than 14%, the disaster-proof mesh sheet will be deficient in toughness and will fail to acquire large falling dart impact strength. If the elongation exceeds 45%, the disaster-proof mesh sheet will suffer heavy dimensional change due to creep and fail to offer lasting service. The elongation at rupture, therefore, must be in the range of 14 - 45% for the sake of the disaster mesh sheet. [0011] The amount of the phthalic ester type plasticizer to be added is in the range of 30 - 85 parts by weight, preferably 50 -80 parts by weight, and particularly preferably 61 - 80 parts by weight, based on 100 parts by weight of the vinyl chloride type paste resin. If this amount is not more than 30 parts by weight, the paste sol composition will acquire unduly high viscosity and incur difficulty in coating the multifilament yarns uniformly and the coating yarn having a uniform coating layer will be obtained only with difficulty. If the amount exceeds 85 parts by weight, the coating layer will be soft and the mesh sheet will tend to gather dirt when pitched at the site of building construction and consequently tend to discolor. Further, the mesh sheet will offer poor resistance to friction, induce partial separation, and withstand no lasting service. [0012] The amount of the phosphoric ester type plasticizer to be added is in the range of 3 - 30 parts by weight, preferably 4 -20 parts by weight, and particularly preferably 4-14 parts by weight. If this amount is not more than 3 parts by weight, the effect of flame retardancy will be unduly small. If the amount exceeds 30 parts by weight, the discoloration by the solar light will be accelerated. The amount of the inorganic type flame retardant is in the range of 5 - 45 parts by weight, preferably 10 - 40 parts by weight, and particularly preferably 20.1 - 35 parts by weight. If this amount is not more than 5 parts by weight, the flame-retarding effect will be unduly small. If the amount exceeds 45 parts by weight, since the polyvinyl chloride type paste sol composition has proportionately large specific gravity, the coated strands produced by coating the multifilament yarns with the paste sol composition will shed drips and the coated yarns will tend to form an undulating surface and the coated yarns of a smooth surface will not be easily obtained. When the green disaster-proof mesh sheet is woven by a loom using the coated yarns having such an undulating surface, the yarns are broken and the loom is stopped on account of large frictional resistance, with the result that the mesh density will be deprived of evenness and the green sheet of high quality will not be easily woven. [0013] As to the gravimetric ratio of the polyvinyl chloride paste sol composition to the synthetic fibers of the multifilament yarns, if the amount of the polyvinyl chloride type paste sol composition is not more than 110 parts by weight, based on 100 parts by weight of the synthetic fibers of the multifilament yarns, the coating will be formed unevenly and the synthetic fibers of the multifilament yarns will have their skin exposed partly through the coating. Further, the synthetic fibers will suffer deficiency in flame retardancy. If the amount exceeds 350 parts by weight, the produced disaster-proof mesh sheet will be at a disadvantage in weighing so much as to impair the ease of handling. Most advantageously, the vinyl chloride type paste resin to be used in this invention consists of 100% of vinyl chloride monomer. A vinyl chloride-vinyl acetate copolymer resin obtained by copolymerizing vinyl chloride monomer with not more than 10% by weight of vinyl acetate can be used or a copolymer resin obtained by copolymerizing vinyl chloride monomer with not more than 10% by weight of other monomer copolymerizable therewith. If the vinyl chloride monomer content in the copolymer resin is not more than 90% by weight, the paste sol composition will be at a disadvantage in manifesting viscosity of inferior stability. If the average polymerization degree of the vinyl chloride type paste resin is not more than 750, the coating film will be deficient in strength and in resistance to abrasion. If the average polymerization degree exceeds 2,000, the vinyl chloride paste sol composition will be at a disadvantage in being gelated so slowly by heating as to impair the productivity of the coated yarns. To the vinyl chloride resin having an average polymerization degree in the range of 750 - 2,000, the vinyl chloride resin having an average polymerization degree of not more than 750 may be added in a proportion of not more than about 20%, the upper limit which is incapable of inducing a decrease in strength. [0014] As concrete examples of the phthalic ester type plasticizer, such dialkyl phthalates as dinormal alkyl phthalate, diisoalkyl phthalate, and mixed-group dialkyl phthalates may be cited. The dinormal alkyl phthalates are preferred to have alkyl chain lengths of C^ - C^j* ^^ concrete examples of the dinormal alkyl phthalates, dibutyl phthalate, di-n-octyl phthalate, di-n-decyl phthalate, di-n-lauryl phthalate, and diundecyl phthalate may be cited. The diisoalkyl phthalates are preferred to have alkyl chain lengths of Cg - C^j- •^^ concrete examples of the diisoalkyl phthalates, diheptyl phthalate, di-2-ethylhexyl phthalate, diiso-octyl phthalate, dicapryl phthalate, dinonyl phthalate, and diisodecyl phthalate may be cited. As concrete examples of the mixed-group dialkyl phthalates, Cy - C, dialkyl phthalates, Cj -C^Q alkyl phthalates, C^ - C^^ dialkyl phthalates, and C, - C^^ dialkyl phthalates may be cited. Among other plasticizers cited above, di-2-ethylhexyl phthalate, di-n-octyl phthalate, diisooctyl phthalate, C^ - C, dialkyl phthalates, and Cj - C^Q dialkyl phthalates prove particularly advantageous. As concrete examples of the phosphoric ester type plasticizers, phosphoric triaryl type, phosphoric trialkyl type. . and aryl-alkyl mixed phosphoric acid type, the phosphoric triaryl type including tricresyl phosphate and trixylenyl phosphate, the phosphoric trialkyl type including tributyl phosphate, trioctyl phosphate, and tributoxyethyl phosphate, and the alkyl-aryl mixed phosphoric acid type including octyl diphenyl phosphate may be cited. [0015] The total amount of plasticizers to be used in this invention is preferred to be in the range of 50 - 90 parts by weight, based on 100 parts by weight of the vinyl chloride type paste resin. Besides the phthalic ester type plasticizer and the phosphoric ester type plasticizer mentioned above, the plasticizers for use in this invention are preferred to incorporate in a nominal amount therein an epoxy type plasticizer which is effective in preventii;ig the deterioration by the solar light. Such epoxidized soybean oils as are marketed under trademark designations of "Adeka Saiza O-130P" and "Sansozaiza E-2000" are available. Other plasticizers may be additionally used in only small amounts. It is inappropriate to add therein a plasticizer which is capable of accelerating the deterioration by the solar light. The plasticizers which are formed of chlorinated paraffins having chlorination degrees in the range of 40 - 70% are invariably inappropriate for this invention because they promote the discoloration. [0016] As concrete examples of the inorganic flame retardant to be used in this invention, antimony trioxide, hydrated zinc borate, aluminum hydroxide, and antimony silico-oxide may be cited. These inorganic flame retardants, when necessary, may be used in the form of a mixture. Preferably, antimony trioxide alone or a mixture having antimony trioxide as a main component thereof is used. The polyvinyl chloride type paste sol composition of this invention optionally uses additionally such additives as stabilizer, auxiliary stabilizer, ultraviolet absorbent, photostability enhancer, antioxidant, diluent, viscosity enhancer, gelating agent, antifungal agent, algicide, and foaming agent which may be suitably selected and used in suitable amounts. The coating of the synthetic fibers of the multifilament yarns with the vinyl chloride paste sol composition is attained by passing them through a sizing nozzle. The materials which are available for the sizing nozz,le include SUS, copper nitride, ceramics, zinc, iron, -fa, CB//, diamond, and hard metal, for example. The sizing nozzle is optionally coated with a hard film of Tic, Tin, or TiV, for example. [0017] [Mode of Embodiment of the Invention] Now, the method for producing the disaster-proof mesh sheet of this invention will be described below. The disaster-proof mesh sheet of this invention uses the synthetic fibers of multifilament yarns which have been described above. These fibers are coated with the vinyl chloride paste sol composition with the aid of the sizing nozzle. The coated yarns are heated to gelate the sol in the coat and then taken up on a winder. The coated yarns thus taken up on the winder are woven by the use of . a loom. The resultant weave is introduced into a heating oven and heat-treated to adjust mesh density and consequently obtain a green sheet- This green sheet is cut into sections of a prescribed size, manipulated, and furnished with grommets to complete a disaster-proof mesh sheet. The disaster-proof mesh sheets of this invention can be used as spread or pitched at sites of building construction and sites of civil engineering works. Now, this invention will be described more specifically below with reference to working examples. [0018] [Embodiments] Example 1: In a planetary mixer (produced by Shinagawa Kako K.K.), 25 liters in inner volume, 100 parts by weight of a vinyl chloride paste resin (having an average polymerization degree of 1,600) was placed and then 62 parts by weight of di-2-ethylhexyl phthalate (DOP), 8 parts by weight of tricresyl phosphate (TCP), 3 parts by weight of epoxidized soybean oil (Adeka O-130 P), 3 parts by weight of a liquid Ca-Zn type stabilizer, and 0.5 part by weight of an ultraviolet absorbent (Tinubin 327), invariably based on 100 parts by weight of the vinyl chloride paste resin, were gradually added as kept stirred over a period of about 20 minutes. They were further stirred for about 20 minutes. Then, 22 parts by weight of antimony trioxide (SbjOj) and 5 parts by weight of a gray pigment were adde"d thereto as kept stirred over a period of about 10 minutes. After this addition, they were altogether stirred further at room temperature for one hour. Then, the resultant mixture was subjected under a reduced pressure of 5 mmHg to vacuum deaeration for about one hour to obtain a vinyl chloride paste sol composition, 2,730 cps in viscosity (B type viscosimeter, rotor V-6, 12 rpm, 25°C). The paste sol was placed in a bath. Then, 384 polyester multifilament yarns, 1,750 deniers in total filament size, 4.5 deniers in monofilament size, 8.5 g/denier in tensile strength, and 21% in elongation at rupture, were pinched with pinch rolls through a guide, passed in the bath of the sol through guide rolls, and further passed through a sizing nozzle, 0.8 mm in diameter, to be coated with the paste sol. The resultant strands were heated in a heating oven at 190°C to gelate the strands and produce coated yarns, 4,370 deniers in total filament size. The gravimetric ratio of the vinyl .chloride paste sol composition to the multifilament yarns in the coated yarns was found to be 150/100. Then, the coated yarns were woven with a Kc^lvuA- loom to form a mesh plain weave composed of 52 warps/10 cm and 52 wefts/10 cm at a rate of 50 cm/min. This weave was passed through a heating oven at 150°C to fuse the crossing points of the warps and the wefts and obtain a green disaster-proof mesh sheet of this invention. This green sheet was cut into oblong sections, 190 cm in width and 520 cm in length, manipulated with a sewing machine, and furnished with grommets to afford disaster-proof mesh sheets each measuring 180 cm in width and 510 cm in length. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 1 to 3. [0019] Example 2: The same vinyl chloride paste sol composition as used in Example 1 was placed in a bath. Then 384 polyester multifilament yarns, 2,750 deniers in total filament size, 7.2 deniers in monofilament size, 8.5 g/denier in tensile strength, and 21% in elongation at rupture, were passed in the bath of the paste sol, and passed through a sizing nozzle, 0.8 mm in diameter. The resultant strands were gelated with a heating oven at 190°C, further passed in the bath filled with the paste sol, passed through a sizing nozzle, 0.9 mm in diameter, and again heated with the heating oven to gelate the strands and produce coated yarns, 7,830 deniers in total filament size. The gravimetric ratio of the vinyl chloride paste sol composition to the multifilament yarns in the coat,ed yarns was found to be 185/100. The coated yarns were woven at a ratio of 33 warps/10 cm and 33 wefts/10 cm in the same manner as in Example 1. Then, the weave was heat-treated in the same manner as in Example 1 to obtain a green sheet. This green sheet was cut, manipulated, and finished in the same manner as in Example 1 to obtain disaster-proof mesh sheets. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 1 to 3. [0020] Example 3: A vinyl chloride vinyl paste sol composition was obtained by following the procedure of Example 1 while using the same vinyl chloride paste resin (having an average polymerization degree of 1,000) as in Example 1 and adding thereto 47 parts by weight of DOP, 20 parts by weight of TCP, and 10 parts by weight of SbgOj instead, invariably based on 100 parts by weight of the resin. The sol composition was found to have a viscosity of 4,380 cps. The sol composition was placed in a bath. Then, 420 nylon 6 multifilament yarns, 1,430 deniers in total filament size, 3.4 deniers in monofilament size, 9.3 g/denier in tensile strength, and 25% in elongation at rupture, were coated in the same manner as in Example 1 to obtain coated yarns. In this case, the sizing nozzle had a diameter of 0.7 mm. The coated yarns were found to have a total filament size of 3,340 deniers. The gravimetric ratio of the vinyl chloride paste sol composition to the multifilament yarns in the coated yarns was found to be 130/100. A weave was formed by following the procedure of Example 1 while weaving the coated yarns at a rate of 64 warps/10 cm and 64 wefts/10 cm. This weave was heat-treated to produce a green sheet in the same manner as in Example 1. The green sheet was cut, manipulated, and finished in the same manner as in Example 1 to obtain disaster-proof mesh sheets. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 1 to 3. [0021] Example 4: A vinyl chloride paste sol composition, 2,350 cps in viscosity, was obtained by following the procedure of Example 1 while adding 60 parts by weight of DOP, 12 parts by weight of a phosphoric ester type plasticizer (produced by Kyoto Yakuhin K.K. and marketed under product code of "KH-650E"), and 25 parts by weight of SbjOj instead. This paste sol composition was placed . in a bath. Then 240 polyester multifilament yarns, 3,500 deniers in total filament size, 14.6 deniers in monofilament size, 8.3 g/denier in tensile strength, and 22% in elongation at rupture, were treated in the same manner as in Example 2 to obtain coated yarns, 12,250 deniers in total filament size. The gravimetric ratio of the vinyl chloride paste sol composition to the multifilament yarns in the coated yarns was found to be 250/100, A weave was formed of the coated yarns at a ratio of 30 warps/10 cm and 30 wefts/10 cm in the same manner as in Example 1. The weave was treated in the same manner as in Example 1 to obtain a green sheet. The green sheet was cut, manipulated, and finished in the same manner as in Example 1 to obtain disaster-proof mesh sheets. The disaster-proof mesh sheets were tested for properties. The results are shown in Table 1 to 3. [0022] Example 5: A vinyl chloride paste sol composition was produced by following the procedure of Example 1 while changing the amount of SbjOj to 12 parts by weight. This paste sol composition was found to have a viscosity of 2,410 cps. This paste sold composition was placed in a bath. Then, 384 polyester multifilament yarns, 3,000 deniers in total filament size, 7.8 deniers in monofilament size, 8.5 g/denier in tensile strength, and 18% in elongation at rupture were coated in the same manner as in Example 1 to produce coated yarns. The coated yarns were found to have a total filament size of 7,460 deniers. The gravimetric ratio of the vinyl chloride paste sol composition to the multifilament yarns in the coated yarns was found to be 140/100. A weave was formed of the coated yarns at a ratio of 33 warps/10 cm and 33 wefts/10 cm in the same manner as _ in Example 1. Then, the weave was heat-treated in the same manner as in Example 1 to obtain a green sheet. This green sheet was cut, manipulated, and finished in the same manner as in Example 1 to obtain disaster-proof mesh sheets. These disaster-proof mesh sheets were tested for properties. The results are shown in Tables 1 to 3. [0023] Example 6 : A vinyl chloride paste sol composition was produced by following the procedure of Example 1 while adding 7 0 parts by weight of DOP, 3 parts by weight of TCP, 25 parts by weight of SbjOj, and 10 parts by weight of aluminum hydroxide [Al(0H)3]. The paste sold composition was found to have a viscosity of 3,260 cps. This paste sol composition was placed in a bath. Then, 240 polyester multifilament yarns, 1,500 deniers in total filament size, 6.3 deniers in monofilament size, 8.5 g/denier in tensile strength, and 22% in elongation at rupture, were coated in the same manner as in Example 2 to obtain coated yarns. The coated yarns were found to have a total filament size of 4,520 deniers. The gravimetric ratio of the vinyl chloride paste sol composition to the multifilament yarns in the coated yarns was found to be 200/100. A weave was formed by following the procedure of Example 1 while using the coated yarns at a ratio of 64 warps/10 cm and 64 wefts/10 cm instead. Then, the weave was heat-treated in the same manner as in Example 1 to obtain a green sheet. The green sheet was cut, manipulated, and finished in the same manner as in Example 1 to obtain disaster-proof mesh sheets. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 1 to 3. [0024] [Table 1] [0025] [Table 2] [0026] [Table 3] [0027] Comparative Example 1: A vinyl chloride paste sol composition, 2,650 cps in sol viscosity, was obtained by following the procedure of Example 1 while using 40 parts by weight of DOP and 20 parts by weight of TCP as plasticizers and adding 15 parts by weight of paraffin chloride (Cl 40%) (produced by Ajinomoto K.K. and marketed under trademark designation of "Enpara 40") instead. Disaster-proof mesh sheets were produced by using the paste sol composition in the same manner as in Example 1. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 4 to 6. [0028] Comparative Example 2: A vinyl chloride paste sol composition, 2,550 cps in sol viscosity, was obtained by following the procedure of Example 1 while using 30 parts by weight of DOP and 35 parts by weight of TCP as plasticizers and adding 8 parts by weight of paraffin chloride (Cl 4 5%) (produced by Adeka-Argas K.K. and marketed under trademark designation of "Adeka-Saiza E-450") instead. Disaster-proof mesh sheets were produced by using the paste sol composition in the same manner as in Example 1. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 4 to 6. [0029] Comparative Example 3: Disaster-proof mesh sheets were obtained by following the procedure of Example 2 while using 140 polyester multifilament yarns, 2,750 deniers in total filament size, 19.6 deniers in monofilament size, 8.5 g/denier in tensile strength, and 21% in elongation at rupture, instead. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 4 to 6. [0030] Comparative Example 4: Disaster-proof mesh sheets were obtained by following the procedure of Example 1 while using 384 polyester multifilament yarns, 1,750 deniers in total filament size, 4.5 deniers in monofilament size, 5.7 g/denier in tensile strength, and 24% in elongation at rupture, instead. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 4 to 6 . [0031] Comparative Example 5: Disaster-proof mesh sheets were obtained by following the procedure of Example 1 while using 384 polyester multifilament yarns, 4.5 deniers in monofilament size, 8.6 g/denier in tensile strength, and 12% in elongation at rupture, instead. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 4 to 6. [0032] Comparative Example 6: Coated yarns were obtained by following the procedure of Example 1 while using 120 nylon 6 multifilament yarns, 860 deniers in total filament size, 7.2 deniers in monofilament size, 9.3 g/denier in tensile strength, and 24% in elongation at rupture, instead. Disaster-proof mesh sheets were obtained by following the procedure of Example while weaving the coated fibers at a ratio of 64 warps/10 cm and 64 wefts/10 cm. The disaster-proof mesh sheets were tested for properties. The results are shown in Tables 4 to 6. [0033] [Table 4] [0034] [Table 5] [0035] [Table 6] [0036] The properties were determined and rated severally by the following methods. (1) Tensile strength and elongation at rupture of yarns These properties were determined by the methods specified in JIS (Japanese Industrial Standard) L-1017, with necessary modifications. (2) Tensile strength and elongation at rupture of disaster-proof mesh sheets These properties were determined by the methods specified in JIS L-1068, with necessary modifications. (3) Falling dart impact strength (penetrating property) This property was determined by the method specified in JIS A 8952, with necessary modifications. (4) Flame retardancy This property was determined by A-2 method (45° Meckel"s burner method) specified in JIS L-1091, with necessary modifications. (5) Weatherability 1) Accelerated test for weatherability Test for tensile strength A. Accelerated test a) Device,used: UV tester b) Conditions: Temperature 63°C Cycle mode: LIGHT = 4 hr DEW = 4 hr B. Test for tensile strength: JIS L-1068 was used with necessary modifications. Test for discoloration A. Accelerated test This test was performed under the same conditions as in A of above. B. Rating of discoloration: JIS L-0804 was used with necessary modifications, 2) Exposure test Exposure of test piece used for determination of falling dart impact strength: The test piece set upright facing to the south by means of temporary scaffolding pipes and exposed to the solar light in accordance with JIS Z-2381, with necessary modifications. Exposure of test piece used for determination of tensile strength: The test piece directly exposed to the solar light in accordance with JIS Z-2381, with necessary modifications. Exposure of test piece used for determination of discoloration: The test piece directly exposed to the solar light in accordance with JIS Z-2381, with necessary modifications. After 0.5 year"s, one year"s, or 3 years" exposure, the test piece was kept immerspd in a 0.4 aqueous solution of a detergent (produced by Kao Soap K.K. and marketed under trademark designation of "Tomi Green") for three hours, immediately cleaned 10 times with a sponge scrubber, rated for discoloration, replaced to the same position, and exposed to the solar light. Test for tensile strength: JIS L-1068 was used, with necessary modifications. Rating of discoloration: A sample was compared with a conserving grade sample, with the discoloration rated by the five-point scale, wherein: 5 stands for only slight change, 4 for fair change, 3 for distinct change, 4 for appreciable change, and 5 for very large change Test for flame retardancy: JIS 1091, A2 was used. Test by direct exposure to flame: JIS 1091, D was used. (6) Determination of vinyl chloride paste sol viscosity The viscosity was determined with a B type viscosimeter, rotor V6, 12 rpm, at 25°C. [0037] [Effect of the Invention] The disaster-proof mesh sheet of this invention suffers neither loss of rigidity nor discoloration, excels in flame retardancy, and exhibits perfeqt falling dart impact strength. WE CLAIM: 1. A disaster-proof mesh sheet produced by preparing a coated yam by coating a multifilament yam with a polyvinyl chloride type paste sol composition, weaving said coated yam, and finishing the weave characterized in that a. said multifilament yarn is synthetic fibers having a monofilament size in the range of 3 -17 deniers, a total size in the range of 1000-4500 deniers, a tensile strength in the range of 6.5 -10^ g/denier, and an elongation at rupture in the range of 14-45% and b. said polyvinyl chloride type paste sol composition is a paste sol composition containing 100 parts by weight of a polyvinyl chloride type paste sol, 30-85 parts by weight of a ophthalmic ester type plasticizer, 3-30 parts by weight of a phosphoric ester type plasticizer and 5-45 parts by weight of an inorganic flame retardant. 2. A disaster-proof mesh sheet as claimed in claim 1, wherein the gravimetric ratio of said multifilament yarn to said polyvinyl chloride type paste sol composition is such that said polyvinyl chloride type paste sol amounts to 110-3 50 parts by weight per 100 parts by weight of said multifilament yarn. 3. A disaster-proof mesh sheet as claimed in claim 1 or 2, wherein said multifilament yarn is the fibers selected from among polyester fibers, nylon fibers, polypropylene fibers, and vinylon fibers. 4. A disaster-proof mesh sheet as claimed in any of claims 1 to 3, wherein said polyvinyl chloride type paste resin has a vinyl chloride content of not less than 90% and an average polymerization degree in the range of 750 -2000. 5. A disaster-proof mesh sheet as claimed in any of claims 1 to 4, wherein said plasticizers incorporate therein 1-8 parts by weight of an epoxy type plasticizer based on 100 parts by weight thereof 6. A disaster-proof mesh sheet as claimed in any of claims 1 to 5, wherein said plasticizers do not contain a halogen-containing plasticizer. 7.A disaster proof mesh sheet as claimed 1 to 6, wherein the woven disaster mesh sheet is finished by a heat treatment

Documents:

1890-mas-1997 abstract duplicate.pdf

1890-mas-1997 abstract.pdf

1890-mas-1997 claims duplicate.pdf

1890-mas-1997 claims.pdf

1890-mas-1997 correspondence others.pdf

1890-mas-1997 correspondence po.pdf

1890-mas-1997 description (complete) duplicate.pdf

1890-mas-1997 description (complete).pdf

1890-mas-1997 form-1.pdf

1890-mas-1997 form-19.pdf

1890-mas-1997 form-26.pdf

1890-mas-1997 form-3.pdf

1890-mas-1997 form-4.pdf

1890-mas-1997 others.pdf

1890-mas-1997 petition.pdf