JP2007197869A - Net for preventing concrete from dropping - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a net for preventing concrete from dropping, not only having excellent physical characteristics such as strength and shock-absorptivity, and chemical characteristics such as flame retardance, weather resistance and chemical resistance, but also having very little deterioration of the flame retardancy while being subjected to practical use. <P>SOLUTION: The net for preventing the concrete from dropping is a multifilament having 1.5-100 dtex single filament fineness and 4.5-10 cN/dtex strength, uses a polyamide fiber containing a 1-10 wt.% triazine compound as at least a part of a constituent materials, and has 5,000-20,000 dtex total fineness of the fiber, and a mesh having 5-20 mm length of one side, and a square shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flame retardant concrete fall prevention net, and more specifically, physical properties such as strength and impact absorption and chemical properties such as flame retardancy, weather resistance and chemical resistance are excellent. In addition, the present invention relates to a concrete fall prevention net with extremely small deterioration in flame retardant performance during practical use.

  The concrete fall prevention net is used as a countermeasure against falling concrete structures such as tunnels, expressways, and bridges.

  These concrete fall prevention nets are required to have physical properties such as shock absorption to prevent breakage due to falling concrete structures, and chemical resistance, especially alkali resistance, to be used in the vicinity of concrete. Polyamide fibers that are excellent in absorption, wear resistance, and chemical resistance have been preferred for concrete fall prevention nets.

  Further, since the concrete fall prevention net is used outdoors, it is required to have excellent weather resistance and flame resistance that does not burn and spread against a vehicle fire or the like. So far, as a method of imparting flame retardancy to concrete fall prevention nets, methods of imparting polyvinyl chloride, urea resin, etc. to nets after netting have been proposed before, but flame retarding by post processing However, not only does the net weight increase and the burden on the worker at the time of enforcement increases, but also the flame retardant effect decreases over time, so flame retardant to raw yarn is required. It was.

  Technology for imparting flame retardancy to polyamide fibers with excellent shock absorption and wear resistance has been well known, but polyamide fibers with sufficient flame retardancy have not yet been realized. The current situation is not.

  For example, a technique for obtaining a composite fiber for a safety net excellent in physical properties and flame retardancy using a flame retardant polyester as a core component and polyamide as a sheath component is known (for example, see Patent Document 1). However, this technology has a problem that the cost increases due to the fiber core / sheath composite, and a problem that the yarn forming property deteriorates due to a composite abnormality.

  Also, a method of obtaining a flame-retardant polyamide filament using a polyamide resin composition containing 98 parts by weight of a polyamide resin having a relative viscosity of 2 to 4 and 2 to 20 parts by weight of a triazine flame retardant having an average particle size of less than 5 μm (for example, In this technique, it is possible to obtain a monofilament excellent in flame retardancy with a maximum strength of 4.4 cN / dtex by adding 5 to 8 parts by weight of melamine cyanurate. It is disclosed that this monofilament can be suitably used as a wire harness protection net. However, the filament made using this technique has the highest strength of 4.4 cN / dtex, and has a problem that it is suitable for use in a concrete fall prevention net that requires higher strength. In addition, this technology is expected to be effective for multifilaments with a large single yarn fineness, but no technology related to multifilaments with a thin single yarn fineness has been disclosed. It did not suggest flame retardancy of single-filament fineness multifilaments used to improve the thickness.

Therefore, a method of imparting flame retardancy after using a polyamide fiber as a net is currently used, and it is not only excellent in workability (lightness), but also in the fall of polyamide fiber concrete with less deterioration over time in flame retardancy The current situation is that the prevention net has not yet been obtained.
JP-A-6-313218 JP 2002-173829 A

  The present invention has been achieved as a result of studying the solution of the above-described problems in the prior art, and has been achieved by physical properties such as strength and impact absorbability and chemical properties such as flame retardancy, weather resistance and chemical resistance. The purpose of the present invention is to provide a concrete fall prevention net that is not only excellent in physical properties such as mechanical properties, but also has very little deterioration in flame retardant performance during practical use.

  In order to achieve the above object, according to the present invention, a polyamide fiber comprising a multifilament having a single yarn fineness of 1.5 to 40 dtex and a strength of 4.5 to 10 cN / dtex and containing 1 to 10% by weight of a triazine compound. Provided is a concrete fall prevention net that is used for at least a part of the constituent material, and has a total fineness of 5000 to 20000 dtex, a mesh side length of 5 to 20 mm, and a mesh shape of squares. Is done.

In the concrete fall prevention net of the present invention,
The triazine compound content of the polyamide fiber is 3 to 10% by weight, and the oil agent is adhered at a ratio of 1.0 to 2.0% by weight with respect to the fiber weight.
The maximum particle size of the triazine compound is 10 μm or less, and the average particle size is 0.1 to 5 μm.
The maximum particle size of the triazine compound is 5 μm or less, and the average particle size is 0.1 to 2.3 μm.
The triazine compound is melamine cyanurate,
The polyamide fiber contains a copper compound as a copper metal amount of 10 to 500 ppm,
The polyamide fiber contains 0.1 to 1% by weight of an organic or inorganic pigment;
Are mentioned as preferable conditions.

  According to the present invention, as described below, not only is it excellent in physical properties such as strength and impact absorbability and chemical properties such as flame retardancy, weather resistance and chemical resistance, but is also practically used. As a result, it is possible to obtain a concrete fall prevention net with very little deterioration in flame retardant performance.

  The present invention will be specifically described below.

  The fibers constituting the concrete fall prevention net of the present invention are required to be polyamide fibers having excellent chemical resistance and abrasion resistance and high toughness. By using polyamide fiber as at least a part of the constituent material of the concrete fall prevention net, it is possible to obtain a concrete fall prevention net that is hardly deteriorated even in an alkaline environment or a friction environment and can be used for a long period of time.

  Examples of the polyamide in the present invention include nylon 4, nylon 6, nylon 11 polycondensed from aminocarboxylic acid and its lactam, and polynylon 4-6, nylon 6-6, nylon obtained by polycondensation of dicarboxylic acid and diamide. Known polyamides such as 6-10 can be used. In addition, the polyamide fiber may contain a copolymer compound, a heterogeneous polymer, or the like as long as the effect of the invention is not impaired, preferably 10% by weight or less, and various light-proofing agents, flameproofing agents, pigments, You may use additives, such as a flame retardant, a matting agent, and a lubricant.

  The single yarn cross section of the polyamide fiber used for the concrete fall prevention net of the present invention may be an irregular cross section other than the round cross section, and the irregular cross sectional shape is a flat type, a triangular type, a C type, a Y type, a dumpling type. A hollow type, a combination thereof, or the like can be exemplified, but is not limited thereto.

  The strength of the polyamide fiber constituting the concrete fall prevention net of the present invention is required to be 4.5 to 10 cN / dtex. If the strength is less than 4.5 cN / dtex, the amount of fibers required when obtaining a base fabric having the strength required as a concrete fall prevention net increases, and the resulting concrete fall prevention net is hard. Since it becomes a product inferior in storage property, it is not preferable. There is no particular upper limit to the strength, but it is difficult with current technology to obtain a fiber having a strength exceeding 10 cN / dtex at low cost.

  The polyamide fiber used for the concrete fall prevention net of the present invention contains 1 to 10% by weight of a triazine compound, preferably 3 to 10% by weight, more preferably 3 to 7% by weight, and exhibits excellent flame retardancy. It is necessary for expression.

  If the content of the triazine compound contained in the polyamide multifilament is less than 1% by weight, the required flame retardancy cannot be obtained. Conversely, if it exceeds 10% by weight, the flame retardant effect is saturated, Rather, it is not preferable because the strength is lowered, and yarn breakage and fluff are generated to reduce the yield of yarn production.

  Further, when the content of the triazine compound is 3 to 10% by weight, the oil agent to be imparted to the polyamide fiber is preferably in a ratio of 1.0 to 2.0% by weight with respect to the fiber weight, and more preferably range. Is 1.2 to 2.0% by weight. When the addition amount of the triazine compound is 3% by weight or more, irregularities that are considered to be caused by the triazine compound appear on the fiber surface. For this reason, the polyamide fiber having a triazine compound content of 3% by weight or more tends to deteriorate the stretchability (spinning property). However, even when the triazine compound content exceeds 3% by weight as described above, it is possible to obtain a polyamide fiber with good yarn-making property by setting the oil agent adhesion amount within the range of the present invention. That is, in the process of producing a polyamide fiber containing 3% by weight or more of a triazine compound, if the amount of the oil agent adhering to the fiber is less than 1.0% by weight, the yarn is produced due to irregularities that may be caused by the triazine compound. However, it is possible to obtain a polyamide fiber with a good yarn-forming property when the amount of oil attached is 1% by weight or more. Further, although there is essentially no upper limit to the amount of oil agent attached, if the amount of oil agent attached exceeds 2.0% by weight, the cost increases, which is not practical.

  The oil agent to be used may be either an aqueous oil agent or a non-aqueous oil agent, but it is preferable to use a non-aqueous oil agent. Further, a preferred oil agent composition is, for example, a non-aqueous oil agent obtained by diluting an alkyl ether ester as a smoothing agent component, an alkylene oxide adduct of a higher alcohol as a surfactant component, and an organic phosphate salt as an extreme pressure agent component with a mineral oil. However, the present invention is not limited to this.

  The triazine compound added to the flame retardant polyamide multifilament of the present invention has an average particle size of 0.1 to 5 μm, more preferably 0.1 to 4 μm, most preferably 0.1 to 2.3 μm. is there. Even if a triazine compound having a particle size of less than 0.1 μm is added to the polyamide polymer, the polyamide fiber becomes aggregated particles of 0.1 μm or more, and more than 5 μm, due to secondary aggregation. It is difficult to produce fibers with good yield.

  The maximum particle size of the triazine compound is 10 μm or less, more preferably 8 μm or less, and most preferably 5 μm or less. When a triazine compound is used for a multifilament such as that used in the concrete fall prevention net of the present invention, if the maximum particle size of the triazine compound exceeds 10 μm, there is a probability of aggregation with other triazine compounds in the molten polymer. As a result, the spinning property is remarkably lowered, and the dispersion state of the triazine compound in the fiber is deteriorated, so that it is difficult to obtain a high-strength fiber suitable for a concrete fall prevention net.

  As a method for confirming the dispersion state of the triazine compound in the fiber, a yarn sample cut to 5 to 10 μm with a microtome was photographed at 400 to 500 times using a Nikon Corporation “ECLIPSE E600W POL” polarizing microscope. It can be confirmed by a photo.

  The triazine compound having the above particle diameter can be obtained by a method such as dry classification after pulverizing the triazine compound by means of a ball mill or the like.

  Examples of the triazine compound used in the present invention include melamines and cyanuric acids, and adducts of melamines and cyanuric acids. Examples of cyanuric acids include cyanuric acid and isocyanuric acid, as well as cyanuric acid derivatives such as trimethylcyanurate, triethylcyanurate, methylcyanurate, diethylcyanurate, trinormalpropylcyanurate, regardless of enol form or keto form. Can be used. Further, the cyanuric acids may be hydrates or anhydrides. Examples of melamines include melamine, ammelide, ammelin, formoguanamine, guanylmelamine, cyanomelamine, allylguanamine, melam, melem, melamine phosphate, and the like. As an adduct of melamines and cyanuric acids, melamine cyanurate, which is an adduct of melamine and isocyanuric acid, can be exemplified, but an adduct of the melamines and cyanuric acids, preferably an equimolar adduct. The type is not limited. In addition, for example, the melamine and cyanuric acid salts obtained by mixing an aqueous solution of melamines and cyanuric acids to form a salt of both, and then filtering, contain unreacted melamines and cyanuric acids. Also good.

  Among these triazine-based compound flame retardants, cyanuric acid, isocyanuric acid, melamine, and melamicyanurate are preferably used, and melamine cyanurate is most preferable in terms of flame retardancy and processability.

  The total fineness of the polyamide fiber, that is, the net yarn used in the concrete fall prevention net of the present invention is preferably 5000 to 20000 dtex. If it is less than 5000 dtex, sufficient strength to capture a concrete piece cannot be obtained when it is made into a net. Conversely, if it exceeds 20000 dtex, the resulting concrete fall prevention net becomes hard and increases in weight, resulting in poor workability. Since it becomes a product, it is not preferable.

  Moreover, it is preferable that the length of the mesh one side of the concrete fall prevention net | network of this invention is 5-20 mm. When the length of one side of the mesh is less than 5 mm, there is a concern that the mesh will be broken due to ventilation inhibition. Moreover, if the length of one side of the mesh is larger than 20 mm, it is difficult to capture fine concrete pieces.

  The shape of the mesh in the concrete fall prevention net of the present invention needs to be a square. When the mesh shape is other than the square, dripping occurs when the concrete fall prevention net is stretched horizontally, and fine concrete pieces may fall, which is not preferable.

  In order to give the concrete fall prevention net of the present invention flexibility, the polyamide fiber needs to be a multifilament having a single yarn fineness of 1.5 to 40 dtex.

  The technical feature of the present invention is that the use of a triazine-based compound having a maximum particle size within the above range allows a polyamide fiber having high yarn-making properties and high strength even with a multifilament having a single yarn fineness satisfying the range of the present invention. In the polyamide fiber containing the triazine compound and satisfying the scope of the present invention, the fiber surface area is larger than that of the fiber having a large single yarn fineness. The contact area between the flame retardant triazine compound and the flame increases during the net combustion, and an excellent flame retardant effect is exhibited. For this reason, the single fiber fineness of the polyamide fiber of the present invention is required to be 1.5 to 40 dtex, preferably 3 to 30 dtex, more preferably 5 to 20 dtex. When the single yarn fineness is less than 1.5 dtex, the single yarn thickness is small compared to the size of the triazine compound, and there is a possibility that fluff and yarn breakage may occur in the fiber manufacturing process. Moreover, when the single yarn fineness exceeds 40 dtex, the resulting concrete fall prevention net is too strong and may have poor storage and workability.

  In addition, flame retardancy can be further improved by using various flame retardants together with the triazine compound added to the polyamide fiber used in the concrete fall prevention net of the present invention. Preferred flame retardants used in combination include alkali metal hypophosphites or earth metal hypophosphites such as sodium hypophosphite, potassium hypophosphite, calcium hypophosphite, barium hypophosphite, hypophosphite. Examples thereof include magnesium phosphate, aluminum hypophosphite, aluminum hydroxide and magnesium hydroxide, and the amount added is usually 0.1 to 10% by weight, preferably 0.5 to 3% by weight. .

  The total fineness of the polyamide fiber is preferably 500 to 3000 dtex, and a more preferable range of the total fineness is a range of 800 to 2000 dtex. When the total fineness is less than 500 dtex, the productivity of the raw yarn is reduced, so that the cost is increased and there is a possibility that the strength is partially insufficient when the concrete fall prevention net is used. If the total fineness exceeds 3000 dtex, it may be bulky and inferior in handleability.

  Furthermore, in order to prevent the weather resistance deterioration and the heat resistance and strength deterioration of the concrete fall prevention net of the present invention, it is preferable that the polyamide fiber contains 10 to 500 ppm of a copper compound as a copper metal amount. When the amount of copper metal is less than 10 ppm, the effect of improving the weather resistance and heat resistance by the copper compound is low, and when the amount of copper metal exceeds 500 ppm, there is a risk that the copper compound becomes a foreign substance and the spinning performance is deteriorated. . The amount of copper metal contained is preferably 20 to 300 ppm, more preferably 30 to 250 ppm. Examples of the copper compound include, but are not limited to, copper iodide, copper chloride, copper bromide, and the like, and conventionally known inorganic and organic copper salts and simple copper metals can be used.

  The polyamide fiber may contain other heat-resistant agents in addition to the copper compound. Examples of the heat-resistant agent include amine compounds, mercapto compounds, phosphorus compounds, hindered phenol compounds, halogen compounds, alkali metal halides, alkaline earth metal halides, etc., but are not limited thereto, and these Two or more types may be combined. Examples of amine compounds include N, N′-diphenyl-p-phenylenediamine, diallyl-p-phenylenediamine, and di-β-naphthyl-p-phenylenediamine. Examples of mercapto compounds include 2-mercaptobenzo Examples include imidazole and 2-mercaptothiazole. Examples of phosphorus compounds include stearyl phosphate, organic and inorganic phosphoric acid such as phosphorous acid or salts thereof, but are not limited to these. The agent may be added separately or may be added after forming a complex. As the heat-resistant agent added together with the copper compound, a mercapto compound is preferable, and 2-mercaptobenzimidazole is particularly preferably combined. The addition amount of the mercapto compound at that time is preferably 300 to 3000 ppm from the viewpoints of thermal oxidative degradation prevention properties and yarn production properties.

  The sulfuric acid relative viscosity of the polyamide fiber is preferably in the range of 3 to 4.5. It is difficult to obtain polycapramide fibers having a high degree of polymerization with a relative viscosity of sulfuric acid exceeding 4.5 with high productivity and low cost. Moreover, when the relative viscosity of sulfuric acid is less than 3, it is difficult to obtain a fiber having a desired strength, and there is a possibility that the physical properties are greatly deteriorated during long-time storage.

  As long as the above-described conditions of the present invention are satisfied, there are no particular rules regarding various physical properties such as elongation, boiling water shrinkage, and number of entanglements of the polyamide fiber.

  In addition, the polyamide fiber used in the concrete fall prevention net of the present invention preferably contains 0.1 to 2% by weight of an organic or inorganic pigment, and more preferably 0.2 to 0.1.2% by weight. . By using polyamide fiber as an original material, there is no need for dyeing, and there are advantages such as low cost and no generation of waste dyeing liquid, and it is possible to obtain a concrete fall prevention net with a small load on the environment. The kind of pigment to be added is not particularly limited, and known inorganic and organic pigments such as carbon black can be added. Moreover, the concrete fall prevention net using the polyamide fiber which added the pigment also has the advantage that a weather resistance improves. When the amount of pigment added is less than 0.1% by weight, there is a possibility that fibers having the desired color tone cannot be obtained. On the other hand, when the added amount exceeds 2% by weight, there is a possibility that the pigment becomes a foreign substance and cannot be obtained with good fiber production in the fiber production process.

  Next, although an example of the manufacturing method of the polyamide fiber used for the concrete fall prevention net | network of this invention is demonstrated, the manufacturing method of a polyamide fiber is not restricted to this.

  Mixing of the polyamide chip with the flame retardant, the copper compound, and the original pigment may be performed at any stage from immediately after completion of the polycondensation of the polyamide until the polyamide fiber is spun from the spinneret. For example, a flame retardant etc. is added and kneaded into molten polyamide immediately after completion of polycondensation to form a chip, followed by solid phase polymerization, then melt spinning and stretching with an extruder type spinning machine, or a dried polyamide chip, A method in which a flame retardant is kneaded and melt-spun / stretched, or a master chip containing a high concentration of flame retardant by melt-kneading is manufactured. There are methods such as stretching. When the master chip is formed, it is preferable to use a twin-screw extruder type extruder or a static mixer at the time of spinning in order to finely disperse the flame retardant.

  After the yarn spun from the base is cooled and solidified by a cooling device such as cold air, the oil agent is applied, wound around a take-up roller rotating at 300 to 2000 m / min and wound up once, or continuously 2 It is hot-drawn in multiple stages and is wound by a winder. The hot stretching temperature is made at a glass transition point of the polyamide fiber of −10 ° C. to 200 ° C., and the draw ratio is made in the range of 2.5 to 7 times to produce the above-described properties of the polyamide multifilament fiber.

  In this way, the polyamide fiber used for the concrete fall prevention net of the present invention is obtained.

  There are no particular limitations on the method for producing the net of the concrete fall prevention net of the present invention, and a production method such as a crotch knot net, a knotless net, a Russell net, or the like can be used. You may attach edge steel, suspension steel, etc. to the obtained net | network as needed.

  Next, although an example of the manufacturing method of the concrete fall prevention net | network of this invention is shown, a manufacturing method is not restricted to this.

  First, several polyamide fibers are aligned to obtain the fineness required for the mesh yarn. Next, as a method of forming a net, the twisted yarn is subjected to a lower twist to form a lower twisted yarn, two lower twisted yarns are combined and subjected to medium twist, and two intermediate twisted yarns are combined and twisted to apply upper twist. By forming a knot, a knot is formed by combining the knots while forming the knot, and at the same time, a knotless net is formed by a knotless knitting netting machine, and the required number of fibers as the knot The method of knitting the twisted yarn obtained by combining the yarns and twisting the yarn in the opposite direction of the twisting using a Russell knitting machine, etc. be able to. Here, the net has a length of one side of the mesh of 5 to 20 mm, and the shape of the mesh is a square. The obtained net is subjected to heat treatment in a tenter within the range of 100 ° C. to the melting point of the polyamide multifilament. About the tension | tensile_strength given to a net | network at the time of heat setting, 0.05-2 cN / dtex can be illustrated as a preferable range, However It does not restrict | limit in particular.

  Thus, the concrete fall prevention net of the present invention can be obtained.

  Hereinafter, embodiments of the present invention will be described in more detail by way of examples. The definition and measurement method of the characteristics used in the specification text and examples are as follows.

(1) Fineness, strength and elongation of polyamide multifilament Measured according to JIS L1013 (1999).

(2) Relative viscosity of sulfuric acid A polymer sample was dissolved in 98% sulfuric acid at a concentration of 1% by weight, measured at 25 ° C. using an Ostwald viscometer, and determined according to the following formula.
Sulfuric acid relative viscosity (ηr) = (sample solution dropping time) / (sulfuric acid solution dropping time)
Each sample was measured twice and the average value was adopted.

(3) Spinnability With respect to yarn breakage per 1t of single yarn when obtaining polyamide fiber yarns, the yarn production was evaluated according to the following criteria.
A: Less than 1 thread break, ○: 1 to less than 3 thread breaks, Δ: 3 to less than 5 thread breaks, X: 5 or more thread breaks.

(4) Amount of oil agent attached A sample is weighed and immersed in 40 ml of carbon tetrachloride, and then shaken for 10 minutes to extract the oil agent. After measuring the absorbance of the extracted solution at 2930 cm ⁻¹ using an infrared spectrometer (FTIR-8400S, manufactured by Shimadzu Corporation), the oil adhesion amount was determined using the following formula. In addition, the average value of 2 times of measurement was made into oil agent adhesion amount.
Oil adhesion amount (% by weight) = (A × K × 0.4) / S × 100 × (100 / (100−official moisture content))
Here, A is the absorbance at 2930 cm ⁻¹ , K is the calibration curve constant, and S is the sample weight.
The calibration curve constant was obtained by measuring the absorbance of 2930 cm ⁻¹ of a 100 ml carbon tetrachloride solution with the oil agent concentration changed, and determining the slope of the calibration curve drawn with the horizontal axis representing the absorbance and the vertical axis representing the oil agent amount.

(5) Triazine compound maximum particle size and average particle size The maximum particle size and average particle size of the triazine compound powder were measured using the following methods. The maximum particle size and the average particle size were determined by measuring using a particle size distribution analyzer (SK Laser Micron Sizer: manufactured by Seishin Enterprise).

(6) Maximum particle diameter and average particle diameter of triazine compound in fiber Photographed with a microtome at 5 to 10 μm at 400 to 500 times using Nikon Corporation's “ECLIPSE E600W POL” polarizing microscope The dispersed state of the triazine compound in the fiber was observed from the photograph, and the maximum particle size and average particle size of the triazine compound that could be confirmed on the fiber cross section were measured.

(7) Flame retardance The number of flame contact of the net sample obtained by the above-mentioned method was measured by the flammability test method D (flame contact test) of JIS L1091 (2002) textiles. If the number of times of flame contact is 3 times or more, the required flame retardancy is satisfied.

(8) Mesh size measurement Measured according to JIS A8960 (2004) mesh size measurement test of a vertical net for construction work.

(9) Net yarn strength Measured according to JIS A8960 (2004), one-by-two method for a vertical net for construction work.

(10) Weather resistance strong retention rate Using a xenon weather meter manufactured by Suga Test Instruments Co., Ltd., the test conditions were a temperature of 63 ° C., water spraying, and a weather resistance test was conducted for 250 hours as a black panel method. The ratio (%) of the net strength after the test to the net strength (100%) before the test was determined.

(11) Flame retardance measurement after exposure test A net that was left outdoors for 800 days was measured according to the flammability test method D (flame contact test).

[Example 1]
Nylon 6 polymer with sulfuric acid relative viscosity of 3.8, nylon 6 master polymer with 10% by weight of melamine cyanurate powder with average particle size of 1.2μm and maximum particle size of 4.5μm and 2% by weight of carbon black With continuous metering, the mixture was continuously fed into a twin screw extruder type extruder at 285 ° C. at a ratio of 6: 4 and melted continuously. 100 ppm of copper iodide was added to each polymer.

  The melted polymer is kneaded with an eight-stage static mixer through a pipe at 285 ° C, weighed with a gear pump to a total fineness of 1500 dtex, guided to a spin pack at 285 ° C, and passed through a 30 micron cut filter in the pack. Then, extrusion spinning was performed from a die having 180 single holes each having a hole diameter of 0.5 mm and a hole length of 1.1 mm.

  After passing through a heating cylinder having a length of 20 cm and an ambient temperature of 310 ° C. provided with a spun yarn under the base, cold air of 30 ° C. was blown and solidified at a rate of 40 m / min using a uniflow type chimney. The oil agent which has the following composition was provided with the oil agent roller.

  Iso C24 alcohol / thiodipropionic acid ester (40% by weight), C11-15 alcohol AOA / thiodipropionic acid ester (30% by weight), trimethylolpropane AOA distearate (10% by weight), C8 alcohol AOA (10% by weight) ) Non-aqueous oil agent obtained by diluting hydrogenated castor oil (7% by weight) and stearylamine EO15 (3% by weight) with mineral oil to 20%.

  The yarn provided with the oil was wound up by a first roller (non-heated) having a surface speed of 475 m / min, and then subjected to a stretching process continuously.

  The second roller (55 ° C.) with a speed of 500 m / min, a third roller (90 ° C.) with a speed of 1375 m / min, a fourth roller (155 ° C.) with a speed of 1800 m / min, a speed of 2250 m A nylon 6 multifilament having a total fineness of 1500 dtex was obtained by continuously applying to a fifth roller (195 ° C.) / Min and a sixth roller (130 ° C.) at a speed of 2150 m / min. The characteristics of the obtained nylon 6 multifilament are shown in Table 1.

  The obtained nylon 6 multifilament was netted by a Russell knitting machine so that the total fineness of the net yarn was 12000 dtex and the length of one side of the mesh was 10 mm. The obtained net was subjected to a treatment for 1 minute at a heat setting temperature of 180 ° C. using a tenter. The properties of the obtained concrete fall prevention net were evaluated, and the results are shown in Table 1.

[Example 2]
Nylon 6 polymer and nylon 6 master polymer were mixed at a ratio of 8: 2 and subjected to the spinning process, and the number of revolutions of the oil roller was changed to 2.2 times so that the oil amount shown in Table 1 was obtained. Except for this, the same procedure as in Example 1 was performed. The properties of the obtained nylon 6 multifilament and concrete fall prevention net were evaluated, and the results are shown in Table 1.

[Example 3]
The melamine cyanurate powder having an average particle size of 4.3 μm and a maximum particle size of 8.1 μm was used at the time of producing the master chip, and in order to suppress the occurrence of fluff, the speed of each roller was set to 510 m / min for the first roller, The same procedure as in Example 1 was performed except that the rollers were changed to 535 m / min, the third roller 1470 m / min, the fourth roller 1900 m / min, the fifth roller 2250 m / min, and the sixth roller 2150 m / min. The properties of the obtained nylon 6 multifilament and concrete fall prevention net were evaluated, and the results are shown in Table 1.

[Example 4]
The melamine cyanurate powder having an average particle size of 4.3 μm and a maximum particle size of 8.1 μm was used at the time of producing the master chip, a die having a 75-hole hole was used, and the speed of each roller was set to 510 m / Minute, second roller 535 m / min, third roller 1470 m / min, fourth roller 1900 m / min, fifth roller 2250 m / min, and sixth roller 2150 m / min. It was. The properties of the obtained nylon 6 multifilament and concrete fall prevention net were evaluated, and the results are shown in Table 1.

[Example 5]
The amount of carbon black added at the time of master chip preparation was 0.8% by weight, nylon 6 polymer and nylon 6 master polymer were mixed at a ratio of 2: 8, and subjected to the spinning process, and each roller speed Are changed to the first roller 560 m / min, the second roller 590 m / min, the third roller 1406 m / min, the fourth roller 1830 m / min, the fifth roller 2250 m / min, and the sixth roller 2150 m / min, and the table The same procedure as in Example 1 was performed except that the number of rotations of the oil agent roller was changed so that the oil amount was 1. The properties of the obtained nylon 6 multifilament and concrete fall prevention net were evaluated, and the results are shown in Table 1.

[Example 6]
A melamine cyanurate powder having an average particle size of 4.3 μm and a maximum particle size of 8.1 μm was used at the time of producing the master chip, the amount of carbon black added was 0.8% by weight, and a die having 75 holes was used. Each roller speed is changed to the first roller 560 m / min, the second roller 590 m / min, the third roller 1406 m / min, the fourth roller 1830 m / min, the fifth roller 2250 m / min, and the sixth roller 2150 m / min. This was carried out in the same manner as in Example 1 except that the number of revolutions of the oil agent roller was changed so that the oil amount in Table 1 was obtained. The properties of the obtained nylon 6 multifilament and concrete fall prevention net were evaluated, and the results are shown in Table 1.

[Example 7]
Each roller speed was changed to the first roller 560 m / min, the second roller 590 m / min, the third roller 1406 m / min, the fourth roller 1830 m / min, the fifth roller 2250 m / min, and the sixth roller 2150 m / min. The same procedure as in Example 1 was performed except that the number of revolutions of the oil agent roller was changed so that the oil amount in Table 1 was obtained. The properties of the obtained nylon 6 multifilament and concrete fall prevention net were evaluated, and the results are shown in Table 1.

[Comparative Example 1]
Example except that a nylon 6 master polymer added with 2% by weight of carbon black without adding melamine cyanurate powder was used, and that the number of revolutions of the oil agent roller was changed so that the oil amount shown in Table 1 was obtained. 1 was performed. Flame retardant (Daikyo Chemical Co., Ltd. "Bigor NA-7") 40%, water 58.8%, hard finish (Sumitex Resin M-3 "Sumite Resin M-3") 1 %, 0.2% catalyst (“Sumitex Accelerator ACX” manufactured by Sumitomo Chemical Co., Ltd.) was dipped to a pickup of 70% and dried at 140 ° C. for 2 minutes. The properties of the obtained nylon 6 multifilament and concrete fall prevention net were evaluated, and the results are shown in Table 1.

[Comparative Example 2]
Nylon 6 master polymer and nylon 6 polymer were mixed at a ratio of 9.5: 0.5 and subjected to the spinning process, a nozzle with 30 holes was used, and each roller speed was adjusted to 560 m for the first roller. / Min, the second roller 590 m / min, the third roller 1406 m / min, the fourth roller 1830 m / min, the fifth roller 2250 m / min, the sixth roller 2150 m / min. The same procedure as in Example 1 was performed except that the number of revolutions of the oil roller was changed and the net was made so that the length of one side of the mesh was 100 mm.

[Comparative Example 3]
The melamine cyanurate powder having an average particle size of 11.4 μm and a maximum particle size of 17.2 μm was used at the time of producing the master chip, and the respective roller speeds were the first roller 660 m / min, the second roller 695 m / min, and the third roller The same procedure as in Example 1 was performed except that the settings were changed to 1470 m / min, the fourth roller 1850 m / min, the fifth roller 2250 m / min, and the sixth roller 2150 m / min. The properties of the obtained nylon 6 multifilament and concrete fall prevention net were evaluated, and the results are shown in Table 1.

[Comparative Example 4]
Spinning was performed using only master chips having a relative viscosity of 3.7 obtained by kneading 14% by weight of the melamine cyanurate powder having the average particle size and maximum particle size shown in Table 1 with a molten nylon polymer. It was measured that the total fineness was 3000 dtex using a gear pump, and that each roller speed was 560 m / min for the first roller, 590 m / min for the second roller, 1406 m / min for the third roller, The fourth roller was changed to 1830 m / min, the fifth roller 2250 m / min, and the sixth roller 2150 m / min, the net was made so that the length of one side of the mesh was 100 mm, and the total fineness of the net yarn was 24000 dtex, The procedure was the same as in Example 1 except that the mesh was in a diamond pattern. The properties of the obtained nylon 6 multifilament and concrete fall prevention net were evaluated, and the results are shown in Table 1.

  As is clear from Table 1, the nets of Examples 1 to 7 that satisfy the conditions of the present invention are concrete fall prevention nets that are excellent in flame retardancy after netting without post-processing, and the difficulty thereof. The fuel performance hardly changes even after the deterioration test.

  However, as shown in Comparative Example 1, the net imparted with flame retardancy by post-processing is a concrete fall prevention net with excellent flame retardancy immediately after the flame retardant processing, but when exposed to the outdoors for a long time The flame retardancy was significantly reduced.

  As in Comparative Example 2, when the content of the triazine-based compound is less than that of the present invention, the required flame retardancy cannot be obtained.

  When the average particle size and maximum particle size of the triazine compound exceeded the provisions of the present invention as in Comparative Example 3, it was possible to collect polyamide multifilaments, but fluff was generated in the polyamide multifilament manufacturing process. Occurred frequently, and high-strength fibers required for the concrete fall prevention net could not be collected stably.

  As in Comparative Example 4, when the content of the triazine compound exceeds the provisions of the present invention, it was possible to collect polyamide multifilaments. The fiber could not be collected.

  The concrete fall prevention net of the present invention is excellent not only in physical properties such as strength and impact absorption, but also in chemical properties such as flame retardancy, weather resistance and chemical resistance, as well as flame retardant during practical use. Since it has the characteristic that performance degradation is very small, it can be effectively used as a countermeasure against falling concrete structures such as tunnels, expressways, and bridges.

Claims (7)

  A multifilament having a single yarn fineness of 1.5 to 40 dtex and a strength of 4.5 to 10 cN / dtex, comprising a polyamide fiber containing 1 to 10% by weight of a triazine compound as at least a part of the constituent material, A concrete fall prevention net characterized in that the total fineness of the fibers is 5000 to 20000 dtex, the length of one side of the mesh is 5 to 20 mm, and the shape of the mesh is square.   The triazine compound content of the polyamide fiber is 3 to 10% by weight, and the oil agent is attached at a ratio of 1.0 to 2.0% by weight with respect to the fiber weight. Concrete fall prevention net. 3. The concrete fall prevention net according to claim 1, wherein the triazine compound has a maximum particle size of 10 μm or less and an average particle size of 0.1 to 5 μm.   4. The concrete fall prevention net according to claim 1, wherein the triazine compound has a maximum particle size of 5 μm or less and an average particle size of 0.1 to 2.3 μm.   The concrete fall prevention net according to any one of claims 1 to 4, wherein the triazine compound is melamine cyanurate.   The said polyamide fiber contains 10-500 ppm of copper compounds as a copper metal amount, The concrete fall prevention net of any one of Claims 1-5 characterized by the above-mentioned.   The concrete falling prevention net according to any one of claims 1 to 6, wherein the polyamide fiber contains an organic or inorganic pigment in an amount of 0.1 to 2% by weight.