JP2003201639A - Mesh sheet for construction work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a mesh sheet for construction work which has high tenacity and excellent flexibility and ventilation free from dislocation of meshes. <P>SOLUTION: In this mesh sheet 1 in which weaving structure of warps 2 and wefts 3 comprises a set of three yarns, one of the three yarns is a multifilament 5 made of a thermoplastic resin and the other two yarns are core-sheath conjugate monofilaments 6 composed of a core layer made of a high-melting component of a thermoplastic resin and a sheath layer made of a low-melting component of a thermoplastic resin. The mesh sheet for construction work is constituted of a weave of a mock leno weave 4 in which the multifilament 5 is arranged at the center and the monofilaments 6 are arranged at both the sides of the multifilament. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mesh sheet for construction work.

[0002]

2. Description of the Related Art Conventionally, a mesh sheet for construction work is stretched on a scaffold around a building site such as a building to prevent falling of building materials such as bolts. However, the scaffold collapses due to wind pressure. It is required to have appropriate ventilation so that it can be avoided. Therefore, woven fabrics such as coarse plain weave and leno weave are widely used. However, there is a problem in that the tension at the time of stretching and fluttering at the time of use cause misalignment at the intersections of the warp and weft, which causes the sheets to deform due to misalignment of the mesh openings. Woven fabrics such as Russell knitted fabrics that employ 3 to 7 weft gauze fabrics as difficult weaving designs are used. However, even with these woven and knitted fabrics, it is difficult to prevent misalignment completely because the sealing process is not actively performed, and the yarn is bent due to the woven structure and the woven structure is loosened. Therefore, there were problems such as elongation and strength, and it was not satisfactory.

As a mesh sheet for construction work which has been positively sealed, a polyester multifilament woven fabric coated with polyvinyl chloride for sealing is widely used. The one coated on the entire surface of the base cloth had a problem that toxic chlorine gas was generated at the time of burning, and problems such as stain and odor caused by bleeding of the plasticizer.

In order to solve such a problem, the applicant has disclosed in JP-A-10-266577 that a mesh sheet in which one of warp or weft is polypropylene multifilament and the other is polypropylene monofilament is used. A core-sheath type composite monofilament composed of a core layer composed of a polypropylene high melting point component and a sheath layer composed of a polypropylene low melting point component containing a flame retardant, wherein intersections of warp and weft threads of a mesh sheet are welded by the polypropylene low melting point component. Disclosed is a polypropylene mesh sheet for construction work, which is characterized in that it is subjected to a sealing process.

However, it is important to impart flame retardancy to the mesh sheet for construction work, and multifilament is preferable for imparting flexibility, but it is not advisable to blend a flame retardant into the multifilament. It is difficult to use a monofilament that can contain a flame retardant in combination, but if the fineness of the monofilament is increased to impart sufficient flame retardancy, the flexibility of the monofilament decreases due to its rigidity. There was also.

[0006]

As described above, the mesh sheet for construction work is required to be flexible so that it can be easily folded and is easy to handle at the time of spreading work. Means that it is necessary to reduce the fineness of the warp and weft, and if the fineness is reduced, the strength as a sheet is reduced, and if the driving density is increased to improve the strength, the mesh spacing becomes smaller and the ventilation is reduced. There was a problem. When the fineness is increased to reduce ventilation density in order to improve ventilation, there is a trade-off that the problem is that flexibility is lost and misalignment occurs.

The present invention has been made in view of the above problems, and provides a mesh sheet for construction work having high strength, excellent flexibility, no misalignment, and excellent ventilation. With the goal.

[0008]

In order to achieve the above-mentioned object, the mesh sheet for construction work of the present invention is a mesh sheet in which three woven structures of warp and weft are one set, of which three are One is a multifilament made of thermoplastic resin, the other two are core-sheath type composite monofilaments composed of a core layer made of a high melting point component of thermoplastic resin and a sheath layer made of a low melting point component of thermoplastic resin; A multi-filament is arranged in the center and the monofilaments are arranged on both sides of the multi-filament.

In the above mesh sheet for construction work, the intersection points of the warp and weft threads are welded with the low melting point component of the thermoplastic resin to perform the sealing process, and the wind force coefficient is set to 0.
Those of 8 or less are good.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to FIGS.

In the present invention, the woven structure of the warp yarns 2 and the weft yarns 3 constituting the mesh sheet 1 is set to 3 sets,
It is composed of a dummy weave structure 4. One of the three is a multifilament 5 made of a thermoplastic resin, and the other two are a core composed of a core layer made of a high melting point component of the thermoplastic resin and a sheath layer made of a low melting point component of the thermoplastic resin. A sheath-type composite monofilament 6, which is used as a set of three in which the multifilament 5 is arranged in the center and the monofilaments 6 are arranged on both sides of the multifilament 5, and the space between the warp threads 2 and the weft threads 3 is Is opened to form a gap 7 to produce a mesh sheet.

In the dummy weave design constructed as described above, the warp yarn and the weft yarn are each set of three, two of the three yarns on both sides are plain weaves, and the central yarn is at the intersection. By flying over three threads, the degree to which the threads are tightened at the intersections is reduced compared to plain weave, and as a result, the hardness of the intersections is reduced and the flexibility is improved, and the width of the intersections is changed to plain weave. Since the width is narrower than that of the plain weave, the warp and weft yarns are spaced apart from each other as compared with the plain weave, so that a woven fabric having many gaps can be obtained.

The total fineness of the thermoplastic resin multifilament is preferably 500 to 1500 decitex (hereinafter abbreviated as dt), and more preferably 600 to 1000 dt.
If the total fineness is less than 500 dt, the strength will be insufficient and 150
If it exceeds 0 dt, the flexibility is lowered, and the mesh interval is reduced, so that the ventilation property described later is lowered, which is not preferable.

The above-mentioned thermoplastic resin monofilament is
A core-sheath composite monofilament comprising a core layer made of a high melting point component of a thermoplastic resin and a sheath layer made of a low melting point component of the thermoplastic resin. The fineness of the thermoplastic resin monofilament is preferably 300 to 700 dt, 400 to 600
dt is more preferred. If the fineness is less than 300 dt, the strength will be insufficient, and if it exceeds 700 dt, the flexibility will decrease and
It is not preferable because the mesh interval becomes small and the ventilation property described later is lowered.

The apparent striking density of the warp and the weft formed as a set of three threads is preferably 3 to 10 threads / 25 mm (the actual number is 9 to 30 threads / 25 mm). If the implantation density is less than 3 lines / 25 mm, it is difficult to obtain a predetermined strength, and if it exceeds 10 lines / 25 mm, the flexibility is reduced, and it is difficult to ensure sufficient mesh spacing, resulting in poor ventilation. It is not preferable. The construction work for the mesh sheet, the basis weight is preferably from 80~500g / ^{m 2,} and more preferably at 100 to 300 g / ^{m 2.}

In the present invention, it is preferable that the mesh sheet is subjected to a heat treatment at the intersection of the warp and weft yarns, and a sealing process is performed by welding the low melting point component of the thermoplastic resin coated on the sheath of the monofilament. . At this time,
At the intersection point, two of the three monofilaments are abutted and woven, so that the low melting point component between the two sheaths is welded and two warp and weft yarns are welded in total, four in total. This means that a stronger sealing process will be applied.

In the present invention, it is preferable that the mesh sheet has a wind force coefficient of 0.8 or less in a wind force coefficient measurement test described later. If the wind force coefficient exceeds 0.8, the ventilation is deteriorated, and there is a problem that a scaffold or the like on which a mesh sheet for construction work is spread at a construction site collapses due to wind pressure, which is not preferable.

Examples of the thermoplastic resin used in the present invention include polyolefins such as polyethylene and polypropylene, nylon and polyester. Among them, polyolefins are preferable from the viewpoints of high strength, fiber moldability and low cost. As the polyolefin, specifically, high-density polyethylene, polypropylene and the like, which have excellent stretching effects and high strength, are preferable, and polypropylene is most preferable.

The polypropylene is a known polypropylene copolymer such as propylene homopolymer, ethylene-propylene block copolymer or random copolymer, or a mixture thereof, among which a high strength can be obtained. Propylene homopolymers are desirable for multifilaments, and those having an isotactic pentad ratio of 0.95 or more are preferably adopted.

In the present invention, it is preferable to add a flame retardant to impart flame retardancy. As the flame retardant, known flame retardants such as halogen-based, phosphorus-based, and inorganic-based flame retardants are used, but halogen-based flame retardants are preferable because they are excellent in processability at high temperatures, flame retardant effects, and are inexpensive, and especially bromine. Flame retardants are preferred.

As the bromine-based flame retardant, an aromatic bromine-based flame retardant such as tetrabromobisphenol A, decabrom diphenyl oxide, octabromodiphenyl oxide, bisdibromopropyl ether tetrabromosulfone, hexabromocyclododecane, dibromoethyldibromo. Examples thereof include alicyclic brominated flame retardants such as cyclohexane 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 kinds.
Of these, bisdibromopropyl ether tetrabromosulfone, which is suitable for imparting flame retardancy to polypropylene, is preferable.

It is preferable that the flame retardant is blended in an amount of 0.1 to 1% by weight based on the total weight of the mesh sheet. If the blending ratio is less than 0.1% by weight, the flame retardancy is insufficient, and if it exceeds 1% by weight, the flame retardant effect is not further improved and it is not economical.

In the present invention, in order to improve weather resistance, it is preferable to add a hindered amine light stabilizer and / or an ultraviolet absorber.

Examples of the hindered amine light stabilizer include bis (2,2,6,6-tetramethyl-4-piperidyl)
Sebacate, tetrakis (2,2,6,6-tetramethyl-
4-piperidyl) -1,2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) di (tridecyl) -1,2,3,4- Butane tetracarboxylate, 1- (2-hydroxyethyl) -2,
Polycondensate of 2,6,6-tetramethyl-4-piperidinol and diethyl succinate, 1,6-bis (2,2,6,6-tetramethyl-4-piperidylamino) hexane and 2,4-dichloro Examples thereof include polycondensation products of -6-tertiary octylamino-s-triazine.

As the ultraviolet absorber, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5'-methylenebis (2-hydroxy-4-methoxy) is used. Benzophenone-based UV absorbers such as benzophenone), 2- (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-3'-t-butyl
-5'-methylphenyl) -5-chlorobenzotriazole, 2,2'-methylenebis (4-t-octyl-6-benzotriazole) phenol and other benzotriazole-based UV absorbers, resorcinol monobenzoate, 2,4 -J
-t-butylphenyl-3'-5'-di-t-butyl-4'-hydroxybenzoate, hexadecyl-3-5-di-t-butyl
Examples thereof include benzoate-based UV absorbers such as 4-hydroxybenzoate.

In the present invention, the above flame retardant, light stabilizer,
It is preferable to add an ultraviolet absorber or the like to the composite monofilament before use. It is known that flame retardants and light stabilizers reduce the effect of flame retardants due to their antagonistic effect.For example, as a method of addition, a light stabilizer is added to the core layer of the monofilament, and the flame retardant and ultraviolet rays are added to the sheath layer. A method such as adding an absorbent is preferable.

The mesh sheet obtained as described above is cut into a predetermined size, and is used as a mesh sheet for construction work of the present invention by folding back the periphery or placing eyelets. It is preferable that the mesh sheet for construction work has a performance that passes the strength standard and the flameproof standard defined in JISA8952.

The thermoplastic resin used in the present invention includes an antioxidant, a dispersant, a lubricant, an antistatic agent, a pigment, an inorganic filler, an inorganic flame retardant, a cross-linking agent, within a range not departing from the gist of the present invention. You may mix | blend normally used additives, such as a foaming agent and a nucleating agent.

[0029]

As described above, the mesh sheet for construction work according to the present invention is a mesh sheet having a woven structure of a dummy weave composed of a set of three warps and wefts. At the intersection, the multifilament placed in the center of the three jumps over the three warps or wefts, so the composite monofilaments placed on both sides can come closer, and the overlap of the yarns at the intersection compared to plain weave. It is possible to make the bulkiness due to the overlap of the yarns at the intersections small and to make the mesh interval of the mesh sheet larger with the same fineness. In this way, the multifilament is arranged to provide the flexibility of the fineness of the yarn required to give a predetermined strength, and the thickness of the monofilament required to impart flame retardancy is 2 With the monofilament of No. 1, the flexibility is further improved, and the yarn width is composed of two monofilament widths at the intersections of the warp and weft due to the weave structure of the mock weave, with the strength obtained from three yarns. Moreover, a sufficient mesh interval can be formed due to the bulkiness at the intersection of two lines. The thus-obtained mesh sheet for construction work of the present invention has high strength, flame retardancy, excellent flexibility and ventilation, and practical effects without misalignment.

[0030]

[Test method] 1. Wind force coefficient measurement test: Using a wind tunnel configured between a wind tunnel ceiling B and a wind tunnel floor C as shown in FIG. 3, a wind D is sent from one of the wind tunnels and measured by a pitot tube E. In the wind speed test in which the wind force related to the mesh sheet 1 was measured by the wind tunnel balance A in the range of the wind speed, the wind force coefficient K calculated from the following formula was obtained. K: Wind force coefficient P: Wind force acting on the net (N) q: Velocity pressure (N / m ² ) A: Net area (m ² ) The velocity pressure q is V: wind speed (m / sec) ρ: air density (kg / m ³ ) 2. Stiffness: JIS L1096 (cantilever method) compliant 3. Flame retardance test: JIS A8952 compliant 4. Tensile test: JIS A8952 compliant

[0031]

EXAMPLES Example 1: Polypropylene (MFR = 20 g
/ 10 min., Density = 0.90 g / cm ³ , Tm = 15
8.0 ° C.) was used to form a total fineness of 760 dt / 100f multifilament 5. Then, the composite monofilament 6 was formed as follows. The core layer has polypropylene (MFR = 3.4 g / 10 min., Density = 0.90).
g / cm ³ , Tm = 16.0 ° C.) and 0.1% by weight of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate as a light stabilizer were used. The sheath layer has a propylene-ethylene random copolymer (MFR = 7.0 g
/ 10 min., Density = 0.90 g / cm ³ , Tm = 13
0.0%), 7% by weight of masterbatch containing flame retardant, etc.,
0.5% by weight of (2'-hydroxy-3 'tert-butyl-5'-methylphenyl) 5 chlorobenzotriazole (trade name: Tinuvin 326) as an ultraviolet absorber, hydrotalcite (trade name: DHT-4A) as an acid adsorbent
1% by weight and 1.9% by weight of cyanine green pigment were mixed and used. The masterbatch containing a flame retardant, etc., is a bromine-based flame retardant with respect to 60% by weight of a propylene-ethylene random copolymer. It is a mixture of wt%. The fineness of the composite monofilament 6 was 300 dt / 240 dt in the core layer / sheath layer, and the total fineness was 540 dt. The multifilament 5 thus obtained is arranged in the center, and the composite monofilament 6 is arranged on both sides thereof.
Using a set of books for the warp 2 and the weft 3, an apparent driving density of 6 × 6/25 mm (actual number 18 × 18/25
mm), a mesh sheet 1 having an imitation weave structure 4 was woven.
The obtained mesh sheet 1 has a bending resistance of 182 mm in the longitudinal direction according to JIS-L-1096 (cantilever method),
The flexibility was good. The wind force coefficient is 4m /
Stable between 0.69 and 0.74 between sec and 20 m / sec
The ventilation was good. In addition, the mesh sheet for construction, which is formed by subjecting the above mesh sheet to the sealing process, has a flame contact number of 5 times in the flame retardancy test, and is JIS A895.
Passed the flameproof standard of 2 and the tensile strength is 66.2k in the longitudinal direction.
gf / 3cm, lateral direction 63.8kgf / 3cm, both of which are JIS A8952 class 2 strength standard 50kgf / 3c
It exceeds m.

Comparative Example 1: The same procedure as in Example 1 was carried out except that the weave design was plain weave (see FIG. 2). The plain weave tightened the intersections of the warp and weft yarns to make them bulky, and the mesh spacing was narrower than that of Example 1. The obtained mesh sheet had a bending resistance in the longitudinal direction according to JIS-L-1096 (cantilever method) of 218 mm and poor flexibility.
Further, the wind force coefficient was 0.82 to 0.88 at a wind speed of 4 m / sec to 20 m / sec, and the ventilation was poor.

[Brief description of drawings]

FIG. 1 is a plan view of a mesh sheet having a woven structure of a dummy weave according to an embodiment of the present invention.

FIG. 2 is a plan view of a mesh sheet having a plain weave design according to a comparative example of the present invention.

FIG. 3 is a schematic diagram of a wind force test using a wind tunnel,
(A) is a front view in which a mesh sheet is attached to the wind tunnel balance, and (B) is a side view of an experimental apparatus in which the mesh sheet is attached to the wind tunnel.

[Explanation of symbols]

1 mesh sheet 2 warp 3 weft 4 imitation weave organization 5 multifilament 6 Composite monofilament 7 gap 8 plain weave organization A wind tunnel balance B wind tunnel ceiling C wind tunnel floor D wind E Pitot tube

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) E04G 21/32 E04G 21/32 B // D01F 8/06 D01F 8/06 F term (reference) 4L041 AA07 BA02 BA05 BA21 BA46 BC04 BC11 BD14 CA38 CA42 DD05 4L048 AA15 AA28 AA44 AA48 AA49 AA53 AB06 AB10 AB33 AC09 AC10 AC18 BA06 CA11 DA31

Claims (2)

[Claims] 1. A mesh sheet comprising three warp and weft woven structures, one of which is a thermoplastic resin multifilament, and the other two are thermoplastic resin high melting point components. A core-sheath type composite monofilament composed of a core layer and a sheath layer composed of a thermoplastic resin having a low melting point component, wherein the multifilament is arranged in the center and the monofilaments are arranged on both sides thereof Mesh sheet for construction work. 2. The mesh sheet for construction work according to claim 1, wherein the intersection point of the warp and weft threads is welded with a low melting point component of a thermoplastic resin to perform a sealing process, and the wind force coefficient is 0.8 or less.