JP3415019B2 - Polypropylene mesh sheet for construction work - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to a polypropylene-based mesh sheet for construction work. 2. Description of the Related Art A mesh sheet for construction work is used to prevent bolts and other construction materials from dropping from the construction site at a construction work site such as a building or a house, thereby ensuring the safety of passers-by. It is a sheet body attached to the outer surface of a temporary structure such as a scaffold. These are generally made of a fibrous material made of thermoplastic resin, which is easily flammable, and there is a danger that they will spread due to welding sparks or the like. For that, JI
Table 1 of Appendix of SA8952 “Sheet for Building Work” defines the flameproof standard, and it is customary that various flame retarding treatments are applied to pass the standard. [0003] More specifically, mesh sheets for building works are often formed by laminating a woven or knitted fabric using a filament yarn such as polyester or nylon with a polyvinyl chloride-based resin. The advantage is that the strength of the woven and knitted fabric is sufficient and it is flexible, and the flame resistance is given by the polyvinyl chloride resin.
As a disadvantage, the laminated polyvinyl chloride resin has problems such as dirt and odor due to bleeding of the plasticizer,
In addition, due to the relatively heavy weight, labor is required for the spreading work at a high place, and furthermore, handling is difficult, such as generation of toxic gas during incineration in disposal. Further, the polyvinyl chloride-based resin has a problem that it is hardened at a low temperature, is difficult to handle, and is brittle, and its strength is reduced. In order to solve such a problem, in recent years,
A mesh sheet made of polyolefin filaments having excellent filament formability and generating no toxic gas is used. In particular, polypropylene monofilaments having excellent mechanical properties are often used. However,
A woven or knitted fabric using a polypropylene monofilament as a weft yarn has poor flexibility due to the rigidity of the polypropylene, is difficult to fold, and has an inconvenience in that it is not easy to handle in a stretching operation at a construction site. SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a polypropylene mesh sheet for building works which is lightweight, high in strength and excellent in flexibility, and has flame retardancy. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a core layer composed of a polypropylene multifilament and a sheath composed of a polypropylene resin composition containing the following A) to C). An object of the present invention is to provide a polypropylene mesh sheet for construction work characterized by being woven and knitted by using a composite polypropylene filament composed of a layer and a warp and / or a weft. A) 50 to 90% by weight of a polypropylene resin B) 10 to 50% by weight of a soft propylene polymer having a Vicat softening point of less than 100 ° C C) 1 to 20% by weight of a flame retardant (however, A) + B) + C) = 100 BEST MODE FOR CARRYING OUT THE INVENTION The polypropylene used for the polypropylene multifilament of the present invention is preferably a polypropylene having high crystallinity and a high stretching effect. Specifically, a propylene homopolymer, Examples include a propylene-ethylene block copolymer and a propylene-ethylene random copolymer. Among these, a polypropylene homopolymer having excellent moldability and high strength is preferable, and particularly, the isotactic pentad fraction is 0.9.
Highly crystalline polypropylene of 5 or more is preferred. These polypropylenes may be used alone or in combination of two or more. The melt flow rate of the polypropylene (hereinafter abbreviated as MFR) is 5 to 5.
50 g / 10 min. Is preferred, and 10 to 30 g / 10 min.
min. is more preferable. [0008] The method for producing the polypropylene multifilament is not particularly limited, and a known multifilament production method is appropriately employed. The fineness of the multifilament is preferably 100 to 1500 denier (hereinafter, referred to as d), and more preferably 300 to 1000 d. The thus obtained polypropylene multifilament is used as a core layer, and as a sheath layer, A) a polypropylene resin, B) a soft propylene polymer having a Vicat softening point of less than 100 ° C., and C) a polypropylene resin containing a flame retardant. The composition is used to form a core-sheath composite polypropylene filament spun. The polypropylene resin of component A) is not particularly limited, but preferably has a melting point difference of at least 10 ° C., more preferably at least 20 ° C., from the polypropylene used for the core layer. It is suitably used, and specific examples thereof include a propylene-ethylene block copolymer or a random copolymer, and syndiotactic polypropylene. These polypropylene resins may be used alone or in combination of two or more. Of these, a propylene-ethylene random copolymer is preferred. The polypropylene resin has an MFR of preferably 1 to 30 g / 10 min., More preferably 5 to 20 g / 10 min. The component (B) has a Vicat softening point of 100 ° C.
Examples of the propylene-based polymer of less than a) are: a) 10 to 50 parts by weight of a crystalline propylene-based polymer having an isotactic index greater than 80; b) 5 to 20 xylene-insoluble ethylene-containing copolymer at room temperature. Parts by weight and c) a copolymer of ethylene and an α-olefin and optionally a small proportion of a diene, said copolymer comprising 40% by weight of ethylene.
And is soluble in xylene at room temperature)
A propylene-based weight containing 80 parts by weight, wherein the weight percent of the sum of component (b) and component (c) is 50% to 90% and the weight ratio of (b) / (c) is less than 0.4 Coalescing compositions. As the crystalline propylene polymer of the component (a), propylene homopolymer or propylene and ethylene or an α-olefin other than propylene (particularly having 4 to 4 carbon atoms)
10 is preferable) and a propylene content of 85% by weight or more in monomer conversion. As the α-olefin constituting the copolymer of the component c), those having 4 to 10 carbon atoms as described above are preferable. These propylene-based polymer compositions can be prepared by the multi-stage polymerization of ethylene, propylene and, if necessary, diene by the methods described in JP-A-6-25367 and JP-A-6-25439. It can be obtained by copolymerization. The other soft propylene-based polymer is obtained by randomly copolymerizing propylene and an α-olefin having 2 to 8 carbon atoms.
A copolymer of 35 mol% and 65 to 80 mol% of ethylene, or 0.1 to 20 mol% of diene
An ethylene-propylene copolymer rubber which is an ethylene-propylene-diene copolymer containing is preferably used. Ethylene-propylene copolymer rubber has a density of 0.8
It is a low crystalline or non-crystalline polymer at 5 to 0.90 g / cm ³ . [0015] Such a soft propylene polymer preferably has a Vicat softening point of less than 100 ° C, particularly preferably less than 80 ° C. When the Vicat softening point is 100 ° C. or higher, the low-temperature adhesiveness of the obtained polypropylene mesh sheet for construction work is insufficient, and a sufficient improvement effect cannot be obtained. As the flame retardant as the component (C), known flame retardants such as halogen-based, phosphorus-based, and inorganic-based flame retardants are used. Flame retardants are preferred, and brominated flame retardants are particularly preferred. Examples of the brominated flame retardant include aromatic brominated flame retardants such as tetrabromobisphenol A, decabromodiphenyl oxide, octabromodiphenyl oxide, bisdibromopropyl ether tetrabromobisphenol S, hexabromocyclododecane, and dibromoethyl. Examples thereof include alicyclic brominated flame retardants such as dibromocyclohexane, and liquid brominated flame retardants such as pentabromodiphenyl oxide and tetrabromodiphenyl oxide. These may be used alone or as a mixture of two or more. It is preferable to use antimony trioxide as a flame retardant aid in combination with the bromine flame retardant in view of improving the flame retardant effect. The mixing ratio of the brominated flame retardant to antimony trioxide is not particularly limited, but is 2: 1 to 1
3: 1 is preferred. The bromine-based flame retardant is preferably blended in an amount of 0.1 to 10% by weight, more preferably 0.3 to 2% by weight, based on the total weight of the mesh sheet. If the compounding ratio is less than 0.1% by weight, the flame retardancy is insufficient, and if it exceeds 10% by weight, the effect of the flame retardancy is not further improved and it is not economical. As a specific compounding method, 1 to 20% by weight, preferably 3%
It may be set to 10 to 10% by weight. The MFR of the polypropylene resin composition used for the sheath layer is selected from the range of 1 to 30 g / 10 min., Preferably 5 to 20 g / 10 min. If the MFR is less than 1 g / 10 min., The fluidity will be poor, and if it exceeds 30 g / 10 min., Mechanical properties such as tensile strength will be undesirably reduced. The composition ratio of the core layer / sheath layer in the composite polypropylene filament is preferably from 50/50 to 90/10, and more preferably from 60/40 to 80/20. The method for producing the composite polypropylene filament is not particularly limited, and a known method is employed. That is, a polypropylene multifilament forming a core layer is supplied from a center discharge hole of a die having two well-known discharge holes formed concentrically, and a polypropylene resin composition forming a sheath layer is melt-kneaded by an extruder. And 2
The sheath layer is extruded from the outer layer of the layer die and coated to obtain a composite polypropylene filament. The fineness of the formed composite polypropylene filament is preferably 500-3000 d,
2000d is more preferred. If the fineness is less than 500d, the strength is inferior, and if it exceeds 3000d, the flexibility is undesirably reduced. The composite polypropylene filament formed by the above method is woven and knitted by a conventional loom or knitting machine using a warp and / or a weft to form a mesh body. The weaving and knitting structure of the mesh body is not particularly limited, as long as it has coarseness and air permeability.
Specific examples of the woven fabric include various woven fabrics such as plain weave, woven weave, leno weave, and the like, and the knitted fabric may be either horizontal knit or warp knit. And the like. In the present invention, a polypropylene multifilament, a polypropylene flat yarn, a multilayer composite polypropylene flat yarn, a polypropylene split yarn, a multilayer composite polypropylene split yarn, a polypropylene monofilament, a core-sheath composite polypropylene are used in combination with the composite polypropylene filament. Various filaments such as monofilaments can be used and interwoven without departing from the spirit of the present invention. Preferably, the amount of the various filaments used is less than 50% by weight of the total warp. Known additives such as a flame retardant, an ultraviolet absorber and an acid adsorbent can be added to the various filaments without departing from the spirit of the present invention. These additives may be directly added to a single-layer filament, and may be added to an outer layer, an inner layer, or an inner or outer layer of a composite filament. Specific examples of the above-mentioned ultraviolet absorbers include 2,2.
Benzophenone ultraviolet absorbers such as 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5'-methylenebis (2-hydroxy-4-methoxybenzophenone), (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-
5'-t-octylphenyl) benzotriazole, 2-
(2-hydroxy-3 ', 5'-di-t-butylphenyl) -5
-Chlorobenzotriazole, 2- (2'-hydroxy-
Benzotriazole UV absorbers such as 3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2,2'-methylenebis (4-t-octyl-6-benzotriazole) phenol, resorcinol Monobenzoate, 2,4-di-t-butylphenyl-3'-5'-di-t-butyl-4'-hydroxybenzoate, hexadecyl-3-5
And benzoate-based ultraviolet absorbers such as -di-t-butyl-4-hydroxybenzoate. The compounding ratio of the ultraviolet absorber is preferably 0.1 to 5% by weight, more preferably 0.5 to 2% by weight, based on the sheath layer component. Specific examples of the above acid adsorbent include hydrotalcite, octyltin laurate, metal soap and the like. Examples of the metal soap include calcium stearate and magnesium stearate. The compounding ratio of the acid adsorbent is preferably 0.1 to 5% by weight, more preferably 0.5 to 2% by weight, based on the sheath layer component. The mesh sheet for construction work preferably has a porosity indicating an open state of 20 to 80%, more preferably 30 to 70%, and conforms to Japanese Industrial Standard JIS A89.
At 52, the mesh size is 12 mm or less, and is selected depending on the purpose and application. The basis weight is preferably 8
0~400g / m ^2, more preferably from 100 to 250
g / m ² . In the present invention, it is preferable that the intersections of the warp yarns of the mesh body are sealed by welding the polypropylene resin composition constituting the sheath layer of the composite polypropylene monofilament. The filling process is performed by subjecting the mesh base material to heat treatment by using a known method such as a hot plate contact type, a hot roll type, an infrared irradiation type, a high frequency welder type, and a hot air tenter type. The heat treatment is performed at a temperature lower than the melting point of the polypropylene and higher than the softening point of the polypropylene-based resin composition. It is important that the welding is performed without impairing the stretching effect of the polypropylene. This mesh body is cut into a predetermined size, and is turned into a polypropylene mesh sheet for construction work according to the present invention by, for example, folding the peripheral edge or placing eyelets, but it passes the flameproof standard specified in JISA8952. Those having performance are preferred. The polypropylene and the polypropylene resin composition used in the present invention may contain other thermoplastic resins or an antioxidant, a light stabilizer, a dispersant, a lubricant, an antistatic agent without departing from the scope of the present invention. Ordinarily used additives such as a pigment, an inorganic filler, an inorganic flame retardant, a crosslinking agent, a foaming agent, and a nucleating agent may be blended. EXAMPLES Test method 1. Vicat softening point: JIS K6758 2. Flame retardancy test: JIS A8952 Example 1: Polypropylene (MFR = 20)
g / 10 min., density = 0.90 g / cm ³ , Tm = 1
(58.0 ° C.) to form a multifilament having a total fineness of 680 d / 120 f, which was used as a core layer. A soft propylene polymer for the sheath layer was produced by a two-stage polymerization method of propylene and ethylene. The first stage product of the resulting polymer composition had an ethylene content of 3.0% by weight and a xylene solubles (S _A ) of 9.4% by weight, and the second stage product had a binary copolymer ( b + c) (a total 70% by weight of), xylene solubles (S _F) 63.4 wt%, the component b) 9.45 wt%, was a component c) 60.55 wt%. In the sheath layer, a propylene-ethylene random copolymer (MFR = 16.5 g / 10 min., Density =
0.90 g / cm ³ , Tm = 128.4 ° C.) 63% by weight
And the soft propylene polymer (MFR = 10 g / 1)
0 min., Density = 0.89 g / cm ³ , Vicat softening point 68 ° C.) 30% by weight, master batch 7 containing flame retardant etc.
% By weight of the polypropylene propylene resin composition 100
(2′-hydroxy-3′-tert-butyl-5′-methylphenyl) 5-chlorobenzotriazole (trade name: Tinuvin 326) as an ultraviolet absorber with respect to parts by weight
0.5 parts by weight, 1 part by weight of hydrotalcite (trade name: DHT-4A) as an acid adsorbent, and 1.9 parts by weight of a cyanine green pigment were used. The master batch containing a flame retardant etc. is made of propylene-ethylene random copolymer 60
The mixture contains 15% by weight of bisdibromopropyl ether tetrabromobisphenol S, 15% by weight of decabromodiphenyl oxide, and 10% by weight of antimony trioxide as a brominated flame retardant based on the weight%. The composite polypropylene filament is obtained by supplying a polypropylene multifilament of a core layer from a molding die provided with two layers of discharge holes concentrically and melt-extruding a polypropylene resin composition of a sheath layer by an extruder. A polypropylene filament was formed. The fineness of the obtained composite polypropylene filament was 1200 d. Using the composite polypropylene filament thus obtained as a weft, a plain-woven mesh body having a weft of 16 filaments / inch was woven. Mesh weight is about 2
The porosity was 05 g / m ² and the porosity was 35%. The mesh body was fused at 135 ° C. by a hot air tenter type heating process at 135 ° C. to perform a filling process, and a fringing process was performed to obtain a 1.8 × 5.1 m polypropylene mesh sheet for construction work. Was. The tensile strength of the polypropylene mesh sheet for building work is 77 kgf / 3 cm, and the maximum elongation is 2
At 3.2%, this value passes the JIS L1091 construction work sheet class 2 standard. Moreover, it had the flexibility which can be folded in the longitudinal direction, and the handleability was good. And in the flame retardancy test, the number of times of flame contact is 4 times,
It has passed the flameproof standard of A8952. Further, the tensile strength after irradiation with a weatherometer for 200 hours and 400 hours was 84.6% and 58.4%, and the weather resistance was good. Example 2: In the sheath layer, a propylene-ethylene random copolymer (MFR = 16.5 g / 10 mi) was used.
n., density = 0.90 g / cm ³ , Tm = 128.4 ° C.) 6
3% by weight and ethylene-propylene copolymer rubber (MF
R = 18.0g / 10min., Vicat softening point 60 ° C)
(2'-hydroxy-3'-tert-butyl-5'-methylphenyl) 5-chloro as an ultraviolet absorber with respect to 100 parts by weight of a polypropylene resin composition containing 30% by weight and a master batch containing a flame retardant and the like at 5% by weight. A polypropylene resin composition obtained by blending 0.5 parts by weight of benzotriazole (trade name: Tinuvin 326), 1 part by weight of hydrotalcite (trade name: DHT-4A) as an acid adsorbent, and 1 part by weight of cyanine green pigment. The procedure was performed in the same manner as in Example 1 except that the product was used. The mesh was welded at 140 ° C. at the intersection of warp yarns by a hot air tenter type heating process and subjected to sealing to prepare a mesh sheet for construction work. The tensile strength of this mesh sheet is 76 kgf / 3 cm, and the maximum elongation is 2
At 1.4%, this value passed the JIS L1091 building construction sheet class 2 standard. Moreover, it had the flexibility which can be folded in the longitudinal direction, and the handleability was good. In the flame retardancy test, the number of times of flame contact was 4
It has passed 52 flameproof standards. The residual tensile strength after irradiation with the weatherometer for 200 hours and 400 hours is 8
The weather resistance was good at 3.5% and 59.6%. Comparative Example: A propylene-ethylene random copolymer (MFR = 16.5 g / 10 min.,
Density = 0.90 g / cm ³ , Tm = 128.4 ° C.) 95% by weight, 5% by weight of a master batch containing a flame retardant etc. 100 parts by weight of a polypropylene resin composition, as an ultraviolet absorber (2′- Hydroxy-3 'tert-butyl-5
0.5 parts by weight of '-methylphenyl) 5-chlorobenzotriazole (trade name: Tinuvin 326), 1 part by weight of hydrotalcite (trade name: DHT-4A) as an acid adsorbent, and 1 part by weight of cyanine green pigment. The procedure was performed in the same manner as in Example 1 except that the polypropylene resin composition obtained as described above was used. Note that the filling temperature at the same level as in Example 1 is 1
45 ° C. The maximum tensile point load of the mesh sheet of the comparative example was 68.4 kgf / 3 cm in the warp direction and 62.4 kgf in the weft direction.
f / 3cm, maximum elongation is 22.8% in warp direction, 3 in weft direction
At 4.5%, this value passes the JIS L1091 construction work sheet type 2 standard, but is slightly insufficient. As described above, the mesh sheet for architectural works of the present invention has a polypropylene multifilament as a core layer and a sheath layer containing a specific soft propylene polymer and a flame retardant. By using a composite polypropylene filament using a system resin composition for the warp and / or the weft, it has flexibility and improved low-temperature adhesiveness. For example, the bonding start temperature is reduced by 5 to 10 ° C. as compared with the conventional product. In addition, good sealing can be performed with good productivity. In addition, it was possible to maintain high strength due to the stretching effect without thermal degradation at the time of filling. Furthermore, it has better cold resistance and antifouling property than the conventionally used polyvinyl chloride coating type.

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Claims (1)

(57) [Claim 1] A composite filament comprising a core layer composed of a polypropylene multifilament and a sheath layer composed of a polypropylene-based resin composition containing the following A) to C): And / or a polypropylene mesh sheet for construction work, which is woven and knitted using weft yarns. A) Polypropylene resin 50 to 90% by weight B) Soft propylene polymer having a Vicat softening point of less than 100 ° C. 10 to 50% by weight C) Flame retardant 1 to 20% by weight (however, A) + B) + C) = 100 weight%)