JP2020045592A - Flame-retardant multifilament yarn - Google Patents

Abstract

To provide a flame-retardant multifilament yarn with excellent flame retardance and improved strength.SOLUTION: A flame-retardant multifilament yarn is a multifilament yarn consisting of a plurality of core-sheath type conjugated fibers bundled containing polyethylene terephthalate as a core component and polyester as a sheath component having a flame retardant component. A mass ratio of the core component to the sheath component is 1-4 to 1. The flame-retardant multifilament yarn is characterized in that polyethylene terephthalate as the core component does not contain any additives of inorganic particles, and a tensile strength of the multifilament yarn is 6.5 cN/dt or more.SELECTED DRAWING: None

Description

  The present invention relates to a multifilament yarn having flame retardancy.

  Industrial materials used at construction sites and the like include fabrics such as safety nets and curing nets, and these fabrics are imparted with flame retardancy and flame resistance from the viewpoint of safety. For example, Patent Document 1 discloses a curing net composed of polyester fibers containing 0.3 to 1.3% by weight of a bifunctional phosphorus compound.

JP-A-5-14085

  The present invention is suitably applied as an industrial material used in a construction site or the like, and has an object to obtain a flame-retardant multifilament yarn having improved strength while having excellent flame retardancy. And

  The present inventors have studied to achieve this object, and as a result, the flame retardant component is concentrated on the fiber surface, while the core portion of the fiber does not contain additives such as the flame retardant component. As a result, it has been found that the above-mentioned object is achieved, and the present invention has been achieved.

  The flame-retardant multifilament yarn of the present invention has the following characteristics.

Polyethylene terephthalate as a core component, a multifilament yarn in which a large number of core-sheath composite long fibers having a polyester having a flame-retardant component as a sheath component are bundled,
The mass ratio of the core component and the sheath component is core: sheath = 1 to 4: 1,
The core component polyethylene terephthalate does not contain additives due to inorganic particles,
A flame-retardant multifilament yarn, wherein the tensile strength of the multifilament yarn is 6.5 cN / dtex or more.

  Hereinafter, the present invention will be described in detail.

  The flame-retardant multifilament yarn of the present invention is obtained by bundling a large number of core-sheath composite long fibers.

  The core component of the core-sheath composite long fiber is composed of polyethylene terephthalate. Polyethylene terephthalate constituting the core component does not contain any additives based on inorganic particles. Therefore, it does not include pigments. By not including the additive, the viscosity can be maintained higher, and the mechanical strength of the fiber is improved. The relative viscosity of polyethylene terephthalate as a core component is preferably about 1.4 to 1.7.

  The sheath component is composed of a polyester having a flame retardant component. Polyesters include terephthalic acid, isophthalic acid, naphthalene 2,6-dicarboxylic acid, phthalic acid, aromatic dicarboxylic acids such as α, β- (4-carboxyphenoxy) ethane, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid, etc. Aliphatic dicarboxylic acids or derivatives thereof with ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4-dimethanol, polyethylene glycol, tetramethylene glycol And polyesters which are polycondensed with diol compounds such as the above, and copolymers and mixtures thereof. Among them, polyethylene terephthalate is preferable because of excellent dimensional stability.

  In the core-sheath composite long fiber according to the present invention, only the polyester of the sheath component contains a flame-retardant component, and the core component does not contain a flame-retardant component.

  Examples of the flame retardant component contained in the sheath component include a phosphorus compound, a halogen compound, a phosphorus-halogen compound, antimony trioxide, and an organic sulfur nitrogen compound. Among them, a phosphorus compound is preferably used.

  The content of the phosphorus compound is preferably 2000 ppm or more in the sheath component, more preferably 4000 ppm or more. The upper limit may be about 6000 ppm, but is preferably 5000 ppm or less in consideration of the improvement of the spinning property, fiber strength, cost, and the like.

  Further, it is preferable that the phosphorus atom is contained in an amount of 600 ppm or more based on the mass of the whole core-sheath composite long fiber. Further, while having excellent flame retardancy, taking into account the improvement of the spinning property and the fiber strength, the cost, and the like, 1000 ppm to 1800 ppm is more preferable. In the present invention, by selecting polyethylene terephthalate that does not contain inorganic particles in the core component, by containing a flame-retardant component only in the sheath component, even if not containing a large amount of phosphorus atoms, based on the mass of the entire fiber, That is, even if the amount of phosphorus atoms is in the range of 600 to 1800 ppm, a multifilament yarn exhibiting excellent flame retardancy and having improved mechanical strength can be obtained. The phosphorus atom may be a simple substance or a phosphorus compound, but a bifunctional phosphorus compound is preferred because of its excellent flame retardancy. Further, it is preferable that the bifunctional phosphorus compound is in a state of being copolymerized in the polyester from the viewpoint of improving fiber strength. In order to obtain a copolymerized state in the polyester in this manner, a phosphorus compound is added so as to have a target phosphorus atom content before the polyester polycondensation reaction starts, and the polycondensation reaction is performed once. It is preferable to form chips, and then to carry out solid-phase polymerization in the same manner as in usual polyester.

  It is preferable that the relative viscosity of the polyester of the sheath component is 1.4 to 1.7 from the viewpoint of improving the strength of the fiber and the spinning property.

  When the core-sheath composite long fiber in the present invention is a soaked fiber containing a pigment, the sheath component has a pigment only, and the core component does not contain a pigment. By including the pigment only in the sheath component, the core component is composed only of polyethylene terephthalate without containing inorganic particles, so that the strength is further improved, and a multifilament yarn excellent in mechanical strength can be obtained. Examples of the pigment include inorganic pigments such as iron oxide and ultramarine blue, and organic pigments such as carbon black, and may be appropriately selected according to a desired color. Since carbon black improves weather resistance, it is preferable to add it to industrial materials used outdoors.

  The mass ratio between the core component and the sheath component of the core-sheath composite long fiber is core: sheath = 1 to 4: 1. When the ratio of the core component and the sheath component is the same as the mass of the core component or the mass of the core component exceeds the mass of the sheath component, a multifilament yarn having improved strength can be obtained. It is more preferable that the mass be greater than the mass of the sheath component. When the core / sheath ratio exceeds 4, the sheath component tends to be difficult to coat the core component satisfactorily. In order to prevent the core component containing no flame-retardant component from being exposed on the fiber surface, it is necessary to use a core component. The upper limit of the ratio of / sheath is 4.

  The cross-sectional shape of the core-sheath composite long fiber is not particularly limited, but a circular cross-section is most preferable because of its high strength and excellent stretchability.

  The flame-retardant multifilament yarn of the present invention is constituted by bundling a plurality of the above-mentioned core-sheath composite long fibers. The single fiber fineness of the core-sheath composite long fiber may be arbitrarily set, but is preferably about 5 to 20 dtex. In addition, the number of bundles of the core-sheath composite long fibers for obtaining the multifilament yarn is also arbitrary, but is preferably about 30 to 400. The fineness of the multifilament yarn is also arbitrary, and is preferably about 200 dtex to 5000 dtex.

  Since the flame-retardant multifilament yarn of the present invention is constituted by the core-sheath composite long fiber having the above-described configuration, the tensile strength of the multifilament yarn is 6.5 cN / dtex or more. Naturally, the upper limit of the tensile strength is preferably as large as possible, but is set to about 8.5 cN / dtex. Since the tensile strength of the multifilament yarn is 6.5 cN / dtex or more, it can be suitably used for various industrial materials, and the fabric woven and woven using the multifilament yarn of the present invention can be used, for example, at a construction site. It can be preferably used for a safety net, a curing sheet, a mesh sheet for construction work, and the like used in the like. A known method may be selected as the knitting and weaving, and examples of the woven fabric include plain weave and twill weave. A warp knit is preferably used as a knit or a net, and a Russell net is particularly preferably used.

  The method for producing a flame-retardant multifilament yarn of the present invention will be described by way of an example. First, a core component and a sheath component are prepared, melt-spun using a composite spinning device, and passed through a heating cylinder (set at a temperature ranging from melt spinning temperature to melt spinning temperature + 30 ° C.) installed immediately below the spinning device. Then, cooling air is blown to cool. Thereafter, the unstretched yarn is taken up by one non-heated roller by applying an oil agent, and subsequently, the non-heated yarn is subjected to 1.05 to 1.05 times drawing with two non-heated rollers. While spraying steam at a temperature of 300 to 500 ° C. and a pressure of 0.1 to 1.0 MPa onto the yarn, the yarn is taken up by three rollers at a temperature of 150 to 250 ° C. and stretched 5.0 to 6.5 times. Thereafter, the film is taken up by four rollers at 100 to 250 ° C., subjected to a relaxation treatment of 1 to 10%, and wound up at a speed of 2000 to 4000 m / min to obtain a flame-retardant multifilament yarn.

  In the flame-retardant multifilament yarn of the present invention, the core component is constituted by polyethylene terephthalate containing no additive, and only the sheath component is constituted by the core-sheath composite long fiber constituted by polyester having the flame-retardant component. It has improved strength while exhibiting excellent flame retardancy.

Next, the present invention will be specifically described with reference to examples. Evaluation and the like in the following examples and comparative examples were performed by the following methods.
(1) Relative viscosity A polyester resin was adjusted to a concentration of 0.5 g / dl using an equal mass mixture of phenol and ethane tetrachloride as a solvent, and measured at a temperature of 20 ° C.
(2) Tensile strength, elongation rate and knot strength According to JIS L-1013, using a constant-speed elongation type tensile tester (Autograph AG-I manufactured by Shimadzu Corporation), conditions of a gripping interval of 25 cm and a tensile speed of 30 cm / min. , And a tensile strength, an elongation and a knot strength were measured. Regarding the obtained tensile strength and knot strength, values obtained by dividing by the fineness of the measurement sample were used as the tensile strength and knot strength, respectively.
(3) Flame retardancy Measured according to JIS L-1091 D method (flame contact test). The number of times of measurement was set to 5 times, and the minimum value was set as the number of times of flame contact. In addition, three or more times were considered to be flame retardant.

Example 1
As the core component, a polyethylene terephthalate resin having a relative viscosity of 1.62, which did not contain additives such as a flame retardant, was prepared. On the other hand, as a sheath component, a polyethylene terephthalate resin (flame retardant resin) having a relative viscosity of 1.63 obtained by copolymerizing an ethylene oxide adduct of (2.5 dihydroxyphenyl) diphenylphosphine oxide as a flame retardant at a phosphorus concentration of 4200 ppm, and a blue color A polyethylene terephthalate resin (dyeing resin) containing a pigment is used (a weight ratio of the flame-retardant resin and the dyed resin is mixed at 35: 1), and a weight ratio of core: sheath is 1.5: 1. The melt spinning was performed at a temperature of 290 ° C. using a composite spinning device. The spun yarn is passed through a heating cylinder having a temperature of 300 ° C. and a length of 30 cm, then cooled by cooling air, applied with an oil agent, taken up by one non-heated roller, and subsequently cooled to 1.02 by two non-heated rollers. We doubled and aligned. Subsequently, a steam processing device is installed between the two rollers and the three rollers, and the heated steam at a temperature of 350 ° C. and a pressure of 0.5 MPa is blown toward the traveling direction of the traveling yarn while being drawn by three rollers at a temperature of 200 ° C. and stretched. Stretching was performed at a magnification of 5.23 times. Thereafter, it was taken up with four rollers at 190 ° C., subjected to relaxation heat treatment at a relaxation rate of 3%, and wound up at a speed of 3000 m / min to obtain a flame-retardant multifilament yarn having 1460 dtex 192 filaments.

Example 2
A flame-retardant multifilament yarn was obtained in the same manner as in Example 1, except that the mass ratio of core: sheath was 2: 1.

Comparative Example 1
Using a polyester resin having a relative viscosity of 1.63 obtained by copolymerizing an ethylene oxide adduct of (2.5 dihydroxyphenyl) diphenylphosphine oxide at a phosphorus concentration of 4200 ppm as a flame retardant and a polyester resin containing a blue pigment, a melt spinning apparatus was used. And melt spinning at a temperature of 290 ° C. The spun yarn is passed through a heating cylinder having a temperature of 295 ° C. and a length of 30 cm, then cooled by cooling air, applied with an oil agent, taken up by one non-heated roller, and subsequently cooled by 1.02 with two non-heated rollers. We doubled and aligned. Subsequently, a steam processing device is installed between the two rollers and the three rollers, and the heated steam at a temperature of 350 ° C. and a pressure of 0.5 MPa is blown toward the traveling direction of the traveling yarn while being drawn by three rollers at a temperature of 200 ° C. and stretched. Stretching was performed at a magnification of 5.30 times. Thereafter, the film was taken out with four rollers at 190 ° C., subjected to relaxation heat treatment at a relaxation rate of 3%, and wound up at a speed of 3000 m / min to obtain a flame-retardant polyester fiber of 1460 dtex 192 filament.

As is clear from Table 1, the flame-retardant polyester fibers of Examples 1 and 2 were superior to Comparative Example 1 in strength and knot strength. Note that the spinning and stretching conditions were the same in Example 1 and Comparative Example 1, and only in the stretching ratio, Comparative Example 1 was slightly higher and the strength tended to improve. Was superior in strength. In addition, despite having a lower phosphorus atom content in the fiber than in Comparative Example 1, the fiber had the same good flame retardancy.

Claims (8)

Polyethylene terephthalate as a core component, a multifilament yarn in which a number of core-sheath composite long fibers having a polyester having a flame-retardant component as a sheath component are bundled,
The mass ratio of the core component and the sheath component is core: sheath = 1 to 4: 1,
The core component polyethylene terephthalate does not contain additives due to inorganic particles,
A flame-retardant multifilament yarn, wherein the tensile strength of the multifilament yarn is 6.5 cN / dtex or more.   The flame-retardant multifilament yarn according to claim 1, wherein the polyester having a flame-retardant component is polyethylene terephthalate containing a phosphorus atom.   3. The flame-retardant multifilament yarn according to claim 2, wherein the phosphorus component contained in the sheath component is 2,000 ppm or more, and the amount of the phosphorus atom is 600 to 1800 ppm based on the mass of the whole fiber.   The flame-retardant multifilament yarn according to any one of claims 1 to 3, wherein the sheath component contains a pigment.   A flame-retardant fabric comprising at least the flame-retardant multifilament yarn according to any one of claims 1 to 4 and knitted or woven.   A safety net comprising the flame-retardant fabric according to claim 5.   A curing sheet comprising the flame-retardant fabric according to claim 5. A mesh sheet for construction work, comprising the flame-retardant fabric according to claim 5.