JPH06313218A - Flame retardant conjugate fiber suitable for safety net - Google Patents

Abstract

PURPOSE:To obtain the subject fiber, excellent in physical characteristics such as strength and elongation and flame retardancy by using a high-viscosity specific flame retardant polyester as a core component and a high-viscosity polyamide as a sheath component, spinning conjugate fiber and drawing the resultant conjugate fiber. CONSTITUTION:A flame retardant polyester, prepared by copolymerizing a phosphorus-containing ester-forming compound or containing a phosphorus- containing flame retardant and having >=0.8 intrinsic viscosity is used as a core component and a polyamide having >=1.2 intrinsic viscosity is used as a sheath component. Both the components are subsequently melt spun, hot drawn and then subjected to heat treatment under relaxed conditions to afford conjugate fiber having >=7.0g/d breaking strength and >=15% breaking elongation. The number of filaments is preferably 40-250 and the size is preferably >=500 denier. The resultant fiber is excellent in shock-absorbing properties and dimensional stability and flame retardant effects persist for a long period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant composite fiber which is suitable as a material for a safety net for industrial materials, especially for construction, and can provide a safety net excellent in impact absorption and dimensional stability. It is a thing.

[0002]

2. Description of the Related Art Safety nets for construction are mainly made of synthetic fibers such as polyamide and polyester. However, although the safety net made of polyamide fiber has excellent physical properties such as shock absorption and abrasion resistance and chemical properties such as chemical resistance, it must absorb moisture in the atmosphere during use. Due to this, there is a problem that the elastic modulus is lowered, the shape is changed, and the dimensional stability is deteriorated. Further, although the safety net made of polyester fiber has excellent dimensional stability, it has a problem that its impact absorption is inferior to that of polyamide fiber.

Further, in recent years, materials having excellent flame retardancy have been demanded as materials for construction safety nets. Various polyamide fibers having flame retardancy have been proposed, but there is no effective method and polyamide fibers having good flame retardancy have not been obtained.

Further, as a polyester fiber imparted with flame retardancy, Japanese Patent Publication No. 53-13479 discloses a fiber obtained by kneading the flame retardant component during spinning and copolymerizing the flame retardant component during polymerization. However, in order to improve flame retardancy, it is necessary to contain a large amount of flame retardant components,
There is a problem that physical properties such as weather resistance, strength and elongation of the obtained polyester fiber are deteriorated.

Further, in JP-A-4-174721, a sheath component is polyamide, a core component is flame resistant polyester,
A core-sheath type composite fiber having excellent yarn quality characteristics of polyamide and excellent in flame resistance is disclosed. However,
This composite fiber is suitable for use in clothing and carpets, but since it is made of polyamide and polyester having low intrinsic viscosity as raw materials, it can be used as a safety net for preventing falling objects, and physical properties such as strength and elongation are required. Since the properties are insufficient and the safety net using this composite fiber is inferior in shock absorption and dimensional stability, it cannot be used for industrial materials, especially for safety nets.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and is for a safety net which has high strength and elongation, is excellent in shock absorption and dimensional stability, and can maintain a flame retardant effect for a long period of time. It is intended to provide a flame-retardant composite fiber suitable for.

[0007]

Means for Solving the Problems The inventors of the present invention have made earnest studies to solve such problems, and as a result, used a highly viscous flame-retardant polyester as a core component and a highly viscous polyamide as a sheath component. Thus, the present invention was found by finding that by appropriately setting the spinning and drawing conditions, it is possible to obtain a composite fiber having excellent physical properties such as strength and elongation and flame retardancy, which is suitable for safety nets. .

That is, according to the present invention, in a core-sheath type composite fiber having a flame-retardant polyester as a core component and a polyamide as a sheath component, a phosphorus-containing ester-forming compound is copolymerized or a phosphorus-containing flame retardant is contained, A flame-retardant polyester with an intrinsic viscosity [η] of 0.8 or more is the core component, and an intrinsic viscosity [η] is 1.
2 or more polyamide as a sheath component, and the breaking strength is 7.0
The gist is a flame-retardant conjugate fiber suitable for a safety net, which is characterized by having a breaking elongation of 15% or more and a g / d or more.

The intrinsic viscosity [η] of the polyester in the present invention is measured at a temperature of 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent, and the intrinsic viscosity [η] of polyamide is 96% sulfuric acid. It was measured at a temperature of 25 ° C. as a solvent. The breaking strength and breaking elongation are JIS
It is measured according to L-1013.

The present invention will be described in detail below. First, the polyester of the core component in the present invention includes polyethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene naphthalate and copolymerized polyesters thereof, which are copolymerized with a phosphorus-containing ester-forming compound or containing phosphorus. A polyester containing a flame retardant is preferable, and a polyester obtained by copolymerizing a phosphorus-containing ester forming compound having a good dispersibility of the flame retardant component is more preferable.

Examples of phosphorus-containing ester-forming compounds include various phosphoric acid esters, phosphorous acid esters, and phosphonic acid esters. The method of copolymerizing these with the above-mentioned polyester is not particularly limited, but a method of adding the phosphorus-containing ester-forming compound to the reaction system as it is and reacting it when producing the polyester is industrially preferable.

Examples of the phosphorus-containing flame retardant include polymers derived from the above-mentioned phosphorus-containing ester-forming compounds. To incorporate them in polyester, they are directly mixed with the base polymer at the time of melt spinning and mixed and molded. Alternatively, a master chip of a phosphorus-containing flame retardant and polyester may be prepared, and the master chip may be diluted with a base polymer to carry out mixed spinning.

The polyamide as the sheath component is not particularly limited, but nylon 4, nylon 6, nylon 66, nylon 46, nylon 8, nylon 10, nylon 610, nylon 12 and the like are used.

According to the present invention, a base polyester such as polyethylene terephthalate is copolymerized with a phosphorus-containing ester-forming compound or a phosphorus-containing flame retardant is added, and the phosphorus content in the obtained flame-retardant polyester is In order to impart sufficient flame retardancy to a composite fiber, the phosphorus atom content concentration is preferably 2000 ppm or more. However, if the phosphorus content is too high, spinnability is impaired, so the upper limit of the phosphorus atom content concentration is preferably 30,000 p.
pm.

Further, in relation to the phosphorus atom content in the flame-retardant polyester, the core-sheath composite ratio of the composite fiber is such that the weight ratio of core / sheath is 50/50 to 80/20, especially 50/50. It is preferably 50 to 75/25. When the composite ratio of the core component is less than 50%, the content of phosphorus atoms in the obtained composite fiber becomes small and it becomes difficult to exhibit flame retardant performance. When it exceeds 80%, the core-sheath composite fiber is formed. Difficult to form.

Further, for both core and sheath components, stabilizers such as hindered phenol compounds, cobalt compounds, fluorescent agents, color improving agents such as dyes, pigments such as titanium dioxide, antioxidants, heat-resistant agents, etc. You may make an additive coexist.

The breaking strength of the composite fiber of the present invention is 7.0 g / d.
Or more, preferably 7.5 g / d or more, more preferably 8.
It is 0 g / d or more. By setting the breaking strength to 7.0 g / d or more, the knit strength, which is the basic performance of the safety net,
It has enough strength to withstand falling objects from high places. In addition, by setting the breaking elongation to 15% or more, when the safety net catches a human body that has fallen, the safety net absorbs the falling energy of the human body and has a shock absorbing property that does not give a strong shock to the human body. it can.

In the present invention, the intrinsic viscosity [η] of the flame-retardant polyester as the core component must be 0.8 or more, and the intrinsic viscosity [η] of the polyamide as the sheath component must be 1.2 or more,
To obtain a breaking strength of 7.0 g / d or more and a breaking elongation of 15% or more of the obtained composite fiber, the core-sheath component is subjected to composite spinning at a spinning temperature of 240 to 300 ° C. by an ordinary melt spinning method, and this yarn is used. The strip may be stretched 5.0 to 6.0 times at a stretching temperature of 160 to 200 ° C. and then subjected to a relaxation heat treatment of 1 to 10%.

The stretching ratio is slightly different depending on the intrinsic viscosity of the polymer, the spinning temperature, the melting temperature of the polymer, the core-sheath composite ratio, etc., but if the stretching is more than 6.0 times, peeling between the core-sheath is likely to occur, and 5.0 If it is less than twice, it becomes difficult to satisfy the intended strength and elongation, so 5.0 to 6.0 times is preferable.

The fineness and the number of filaments of the conjugate fiber of the present invention are not particularly limited, but in order to be used for safety nets, the fineness and the number of filaments are 500 denier or more.
It is preferably 40 to 250. Furthermore, in order to prepare a safety net from the composite fiber of the present invention, it is preferable to knit using a Russell knitting machine.

[0021]

In the present invention, since the high-viscosity polyester containing the flame-retardant component is used as the core and the high-viscosity polyamide is used as the composite fiber in the sheath, the flame-retardant component of the core is well protected, The breaking strength is 7.0 g / d or more and the breaking elongation is 15
%, The knitted fabric can provide a safety net having excellent shock absorption and dimensional stability.

[0022]

EXAMPLES Next, the present invention will be specifically described with reference to examples. In the examples, measurement and evaluation of characteristic values were performed by the following methods. (1) Intrinsic viscosity [η] -Measured by the above method. (2) Breaking strength-Measured by the above method. (3) Elongation at break-Measured by the method described above. (4) Flame retardance-In accordance with JIS L-1091 (45 degree coil method), a braid obtained by braiding 8 fibers was used as a sample and expressed as an average value of the number of ignition times for 5 samples. (5) Limiting oxygen index (LOI value) -JIS K 7201
It was measured according to. (6) Weather resistance-A carbon arc fade meter was used to measure the temperature at 83 ° C. and the irradiation time for 200 hours, and the strength before elongation and the retention rate after irradiation with respect to elongation were expressed. (7) Dry heat shrinkage-according to JIS L-1013, 20 at 180 ° C
It was measured after being left for a minute. (8) Hot water shrinkage-according to JIS L-1013, 15 at 100 ° C
It was measured after being left for a minute.

Example 1 Poly (ethylene terephthalate) was mixed with diphenyl- (2,5-
Bis-hydroxyethoxyphenyl) phosphine oxide was copolymerized to obtain a polyester chip having a phosphorus atom content concentration of 7000 ppm and an intrinsic viscosity [η] of 1.05. The above polyester is used as the core component and the intrinsic viscosity [η] is used as the sheath component.
Composite core / sheath ratio (weight ratio) of 50 using nylon 6 of 1.57
/ 50 composite fiber was composite spun at a melting temperature of 295 ° C. Subsequently, these spun yarns were hot-stretched at 200 ° C for one stage of 5.34 times and then subjected to a relaxation heat treatment at a relaxation rate of 5% at 160 ° C to obtain a composite fiber of 500 denier 48 filaments. Using 18 yarns of the obtained composite fiber as loop yarn (9000 denier) and 6 yarns as insert yarn (3000 denier), knitting was performed using a Russell knitting machine, and then at a temperature of 130 to 190 ° C for 10 minutes. Heat setting was performed and a safety net was obtained.

Example 2 The core / sheath composite ratio was changed as shown in Table 1 to 5.28 at 200 ° C.
The same procedure as in Example 1 was carried out except that the double stretching was performed.

Example 3 The core / sheath composite ratio was changed as shown in Table 1 to 5.27 at 200 ° C.
The same procedure as in Example 1 was carried out except that the double stretching was performed.

Example 4 The copolymerization amount of the phosphorus compound was changed so that the phosphorus atom content concentration was 1300.
Example 1 was repeated except that a polyester chip having 0 ppm and an intrinsic viscosity [η] of 1.00 was used as a core component, the core / sheath composite ratio was changed as shown in Table 1, and a stretching of 5.21 times was performed at 195 ° C. I went the same way.

Example 5 The core / sheath composite ratio was changed as shown in Table 1 to 5.28 at 195 ° C.
The same procedure as in Example 4 was carried out except that the double stretching was performed.

Example 6 The core / sheath composite ratio was changed as shown in Table 1 to give 5.17 at 195 ° C.
The same procedure as in Example 4 was carried out except that the double stretching was performed.

Comparative Example 1 The procedure of Example 1 was repeated, except that nylon 6 was melt-spun and drawn 5.00 times at a temperature of 195 ° C.

Comparative Example 2 Polyethylene terephthalate was melt-spun and the temperature was changed.
The same procedure as in Example 1 was carried out except that the film was stretched 5.90 times at 200 ° C.

Comparative Example 3 The procedure of Example 1 was repeated, except that a phosphorus-containing copolymerized polyester having a phosphorus atom content of 7000 ppm was melt-spun and stretched 6.56 times at a temperature of 200 ° C.

Comparative Example 4 The procedure of Example 1 was repeated, except that a phosphorus-containing copolyester having a phosphorus atom content concentration of 13000 ppm was melt-spun and stretched 6.07 times at a temperature of 200 ° C.

Table 1 shows various characteristics of the yarns obtained in Examples 1 to 6 and Comparative Examples 1 to 4.

[0034]

[Table 1]

The composite fibers obtained in Examples 1 to 6 have high breaking strength, breaking elongation, excellent flame retardancy, low hot water shrinkage,
The dry heat shrinkage was shown, and as a result of the weather resistance experiment, the strength and the elongation retention were also good. The safety net obtained from these composite fibers was excellent in strength and elongation, flame retardancy and dimensional stability.

On the other hand, since the yarn obtained in Comparative Example 1 uses only nylon 6 as a raw material, it has a high hot water shrinkage ratio and is inferior in flame retardancy. Since the yarn obtained in Comparative Example 2 uses only polyethylene terephthalate as a raw material, the breaking elongation is low and the flame retardancy is poor. The yarn obtained in Comparative Example 3 had only a phosphorus-containing copolyester having a phosphorus atom content concentration of 7000 ppm as a raw material, and thus had a low elongation at break, high dry heat shrinkage, and poor weather resistance. Since the yarn obtained in Comparative Example 4 uses only the phosphorus-containing copolyester having a phosphorus atom content concentration of 13000 ppm, it has low breaking strength, high dry heat shrinkage, and poor weather resistance.

[0037]

INDUSTRIAL APPLICABILITY The flame-retardant composite fiber suitable for use in the safety net of the present invention has high strength and elongation and improved weather resistance. It becomes possible to provide an excellent safety net.

Claims (1)

[Claims] 1. A core-sheath type composite fiber having a flame-retardant polyester as a core component and a polyamide as a sheath component, which is copolymerized with a phosphorus-containing ester-forming compound or contains a phosphorus-containing flame retardant and has an intrinsic viscosity [η ] 0.8 or more as a core component, a polyamide having an intrinsic viscosity [η] of 1.2 or more as a sheath component, and a breaking strength of 7.0 g / d or more and a breaking elongation of 15% or more. A flame-retardant composite fiber suitable for safety nets.