JP2000328363A - Flame-retardant polyamide fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide flame-retardant polyamide fibers which do not generate a poisonous gas, when burnt, and do not cause a liquid-dripping phenomenon, by an industrially extremely simple method. SOLUTION: The flame-retardant polyamide fibers comprise a flame-retardant composition to which a silicone resin comprising units of the formula: R2SiO1.0 and units of the formula: RSiO1.5 (R is a hydrocarbon group) and having a weight-average mol.wt. of 10,000 to 270,000 is added in an amount of 0.1 to 10 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant polyamide fiber which is difficult to burn, does not generate toxic gas even if burned, and does not cause dripping.

[0002]

2. Description of the Related Art Flame-retardant fibers are highly demanded, but their needs are becoming stronger in the aging society. However, as a conventionally used flame retardant, a halogen compound (for example, JP-A-53-98417) is
Since halogen gas is generated at the time of combustion, it has a serious problem that it is harmful to the human body. Red phosphorus is also proposed to be used because it has a high flame retardant effect (for example, Japanese Patent Application Laid-Open No. 63-110254), but it requires great care in handling and is not suitable for practical use. Phosphorus-based flame retardants (for example, Japanese Patent Publication No. 53-13479) are also used, but also in this case, harmful gases such as phosphine are generated. However, there was a problem such as burns caused by dripping.

[0003]

As described above, although a large number of flame-retardant synthetic fibers have been proposed, due to problems such as generation of harmful gas during combustion, handling of a flame retardant, and dripping phenomenon, they are industrially required. Fibers that can be produced and have sufficient flame retardancy have not yet been obtained. In view of the above problems, an object of the present invention is to provide a flame-retardant polyamide fiber that does not generate a toxic gas during combustion and has no dripping phenomenon by an industrially extremely simple method.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, by adding a silicone resin compound of a flame-retardant composition to a polyamide resin, the present inventors have found that it is possible to prevent dripping without dripping. The inventors have found that a polyamide fiber having a fuel performance can be provided, and have completed the present invention. In this case, since the flame-retardant composition to be added is a silicone-based resin, no toxic gas is generated even if it is burned.

The gist of the present invention is that the flame-retardant composition has the formula R ₂ S
A silicone resin having a unit represented by iO _1.0 and a unit represented by the formula RSiO _1.5 , wherein the weight average molecular weight of the silicone resin is 10,000 or more and 270,000 or less, and R is a hydrocarbon group. A flame-retardant polyamide fiber characterized in that 0.1 to 10% by weight of a silicone resin compound is added.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The silicone resin used in the present invention is composed of four units (M unit, D unit, T unit, and Q unit) represented by the following general formula, and a unit represented by the formula R ₂ SiO _1.0 (D unit)
Having a unit (T unit) represented by preparative formula RSiO _1.5, each R is a selected group from the group consisting of hydrocarbon groups each saturated or aromatic ring, the weight average molecular weight of the silicone resin is 10,000 or more and 270 2,000 or less.

[0007]

Embedded image If the molecular weight (weight average molecular weight) of the silicone resin of the flame-retardant composition is less than 10,000, the viscosity is too low and it is difficult to knead with the polyamide resin. Further, the flame-retardant effect, especially the drip resistance (drip due to the melting of the fiber) during combustion is reduced. On the other hand, if the molecular weight of the silicone resin is too large, the melt viscosity becomes too high, and the kneadability with the thermoplastic resin decreases. Further, the transferability of the silicone resin to the surface of the thermoplastic resin during combustion is reduced, and the formation of a flame-resistant film on the resin surface is reduced, so that the flame retardant effect is also reduced. In particular, the weight average molecular weight is 27
Above 000, the flame retardant effect is greatly reduced.

[0008] For the R ₂ SiO _1.0 unit constituting the silicone resin used in the present invention, the RSiO _1.5 unit is:
Preferably, the molar ratio is 0.5 times or more and less than 7 times. Formula R
When the unit represented by SiO _1.5 is less than 0.5 times the unit represented by the formula R ₂ SiO _1.0 , the silicone resin tends to be oily. Further, since the heat resistance of the silicone resin itself is reduced, the flame retardant effect on the thermoplastic resin is reduced, and the drip is likely to occur. Also, the formula RSi
When the unit represented by O _{1.5 is} at least 7 times the unit represented by the formula R ₂ SiO _1.0 , the dispersion in the thermoplastic resin becomes worse due to steric hindrance, and the silicone resin in the flame resistant film contains Condensation of the phenyl groups of the above is unlikely to occur.

R ₂ SiO _1.0 unit of silicone resin and R
R of the SiO _1.5 unit is a methyl group and a phenyl group,
More preferably, the molar ratio of the phenyl group is 40% or more and less than 80%, and the remainder is a methyl group. If the proportion of the phenyl group is less than 40% by mole, the compatibility with the polyamide resin is reduced, so that the kneading property is reduced. further,
Since the flame resistance of the silicone itself decreases, the flame retardant effect on the polyamide resin also decreases. On the other hand, if the molar ratio of the phenyl group is 80% or more, the compatibility with the polyamide resin becomes too high, so that the transferability of the silicone resin to the polyamide resin surface during combustion of the polyamide resin is reduced. It is difficult to form a flame resistant film on the resin surface. Furthermore, steric hindrance between phenyl groups in the silicone resin makes it difficult for efficient condensation between phenyl groups in the flame-resistant film to occur, and the flame resistance of the film decreases.

The silicone resin has the formula R ₂ SiO
_{In addition} to the unit (D unit) represented by _1.0 and the unit (T unit) represented by the formula RSiO _1.5 , the terminal group is represented by the formula R ′ ₃ SiO
It is preferable for the flame resistance to be composed of a unit (M unit) represented by _0.5 . R ′ in the formula is a saturated hydrocarbon group and / or
Or an aromatic hydrocarbon group, or a saturated hydrocarbon group and / or
Alternatively, a mixed system of an aromatic hydrocarbon group and a hydroxyl group and / or an alkoxy group is preferable, and the hydroxyl group and / or the alkoxy group are less than 10% in a molar ratio, and the remainder is a methyl group and / or a phenyl group. . Hydroxyl group and / or
Alternatively, when the proportion of the alkoxy group is 10% or more, self-condensation of the silicone resin is likely to occur during kneading with the polyamide resin, and as a result, the dispersibility of the silicone resin in the polyamide resin and the combustion The transferability of the silicone resin to the polyamide resin surface is reduced, and the flame retardant effect is reduced.

The proportion of the silicone resin compound in the flame-retardant composition is preferably 0.1% by weight or more and less than 10% by weight based on the whole fibers. If the content is less than 0.1% by weight, the flame retardant effect on the fiber is significantly reduced. On the other hand, when the amount of the silicone resin compound is 10% by weight or more, the spinnability during the fiber forming process is reduced, and the fiber properties of the obtained fiber are also reduced.

The polyamide refers to a polymer having an amide bond formed from, for example, an aminocarboxylic acid, a lactam or a diamine and a dicarboxylic acid, and nylons 6, 66, 46, 10, 12, and 610, etc. Nylon MXD6 having an aromatic ring in the molecular chain
(Metaxylylene adipamide) and the like. However, the third component may be copolymerized within a range that does not impair the fiber forming ability.

In addition to the copolymerization of the third component, an antistatic agent, an antistatic agent, a heat resistant agent, a light stabilizer,
An antioxidant, a fluorescent agent, a pigment, a matting agent and the like may be added. The polyamide resin preferably has a melt viscosity (shear rate of 1000 / sec) of 50 to 10,000 poise, particularly preferably 100 to 5,000 poise, at the temperature at which the fiber is produced. If the melt viscosity is lower than this range, there is no fiber forming ability, and even if fibers are obtained, there is a practical problem such as the strength being too low. Conversely, if the viscosity is higher than this range, it is not possible to follow the deformation during the fiber formation process, which may cause yarn breakage.

As a method of dispersing the flame-retardant composition in the polyamide resin, there are a method of adding the compound at the time of polymerization of the polyamide resin, a method of adding the compound to the chip at the time of spinning, and the like. However, when adding during spinning, it is more preferable to provide a so-called static mixer, for example, in an extruder line or in a spinneret for uniform dispersion.

The cross-sectional shape of the flame-retardant fiber of the present invention is not particularly limited, and may be a circular cross-section, a triangular, hexagonal, flat or other irregular cross-section, or a hollow cross-section.
A plurality of polyamide resins containing the flame-retardant composition in at least one component may be in the form of a composite fiber such as a parallel type, a core-sheath type, or a sea-island type. The flame-retardant fiber of the present invention is usually spun by a known method. That is, using an extruder-type melt-spinning apparatus, the resin is melted at a temperature higher than the melting point, extruded from a spinneret, cooled and solidified to a glass transition temperature or lower, then an oil is applied and taken up by a roller. At this time, the presence / absence of the heating cylinder after being discharged from the spinneret, cooling conditions, and the like are not limited at all.
The so-called POY method, in which the drawn yarn is wound as it is, a so-called spin draw method, in which the yarn is stretched between rollers heated to a temperature higher than the glass transition temperature, and a two-step method in which the yarn is once wound at a low speed and then stretched in another process. For example, it may be processed by any method. Further, a so-called heat tube method in which the film is stretched by a heating cylinder before being taken up by a roller may be used.

The flame-retardant fiber of the present invention is not limited to a fiber composed of one component, and may be a composite fiber composed of two or more components such as a core-sheath type, a side-by-side type and a sea-island type. The flame-retardant composition comprising a silicone compound, or the flame-retardant composition comprising a silicone compound and an alkali metal salt may be added to only one component of the composite fiber, or may be added to a plurality of components in small amounts. However, it is an essential condition that the fiber contains a flame-retardant composition comprising a silicone compound in an amount of 0.1 to 10% by weight as described above.

The flame-retardant fiber of the present invention may be not only a long fiber but also a short fiber cut by applying a crimp. By using these fibers, it is possible to form a nonwoven fabric obtained from these fibers or a spun bond that is sucked by an air jet without being wound up and is thermally bonded. The flame-retardant fiber of the present invention is subjected to a heat treatment at 130 ° C. or higher in the state of the fiber and the fabric, whereby the flame-retardant composition composed of the silicone compound inside the fiber undergoes thermal molecular motion and moves to the fiber surface, As a result, it is assumed that a flame-retardant layer is formed, so that the flame-retardant effect during combustion is significantly improved. Examples of the heat treatment method include a dry heat treatment using a known heater and a method of irradiating an infrared ray or a laser beam.

The flame-retardant fiber thus obtained is a fiber having excellent flame-retardant performance measured as described later, and is used for clothing, interior use such as curtains and sheets, and the like. It can be used in any field such as tarpaulins and industrial materials such as nets. As described above, the flame-retardant polyamide fiber containing the silicone compound of the flame-retardant composition of the present invention hardly ignites, does not generate toxic gas at the time of burning, and suffers burns caused by melt-drops due to dripping. This is an excellent flame-retardant polyamide fiber that does not have any.

[0019]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The method for measuring the characteristic values is as follows.

(A) Relative viscosity of polyamide A solution having a concentration of 1.0 g / deciliter using 96% concentrated sulfuric acid as a solvent was measured at a temperature of 25 ° C. using an Ubbelohde type viscosity tube.

(B) Strength and elongation of fiber Using an Autograph DSS-500 manufactured by Shimadzu Corporation,
Twist of 5 cm was applied twice at a sample length of 30 cm and a grip interval of 5 cm, and the measurement was performed at a tensile speed of 30 cm / min.

(C) Flame retardancy The flame retardancy was measured according to the method D of JIS L1091. That is, the fiber is tubular knitted, and 1 g of the fiber is 10 c in length.
m, inserted into a 10 mm diameter wire coil, and held at an angle of 45 °.
mm.phi.), keep the fire source away, and if the fire is extinguished, repeat the ignition again to determine the number of ignitions required for all the samples to burn out, and calculate the average number of ignitions for five samples (referred to as the number of flames). It was expressed by. (The standard of the Fire Service Law is at least three times.)

(D) Drip In the evaluation of the flame retardancy of (c), it was determined that the dregs dropped from the fibers burned for 1 second or longer, and that drip was not found.

Examples 1 to 6 Nylon 6 having a relative viscosity of 2.5 and silicone resin 23
(Molecular weight 40000, R _TwoSiO_1.0: RSiO_1.5But
Molar ratio of 1: 4, with the phenyl group of R in the silicone resin
The molar ratio of the methyl group is 60:40) in Table 1
Were added together. In the following, silicone resin
Is referred to as "flame retardant resin".

Then, the product obtained by adding the silicone resin 23 to the nylon 6 is supplied to an extruder-type melt spinning apparatus. The spinning temperature is 255 ° C., and the diameter is 0.3 m.
m, discharged from a spinneret having 24 holes, 0.65 m /
Cooling air at a temperature of 15 ° C. is blown onto the running yarn for 2 seconds, and after cooling and solidification, an oil agent is applied, and stretched 1.29 times between a roller at room temperature and a heating roller at 120 ° C. at a speed of 4,300 m / min. To obtain a 70d / 24f nylon fiber. Table 1 shows the yarn quality and flame retardancy.

[0026]

[Table 1] As is clear from Table 1, Examples 2 to 5 which are examples of the present invention
Had excellent yarn quality and flame retardancy. However, in Example 6 where the amount of the flame-retardant resin added was too large, the spinning condition was extremely poor and the yarn breakage was large. The fiber of Example 3 was knitted in a tube and subjected to dry heat treatment at 150 ° C. for 3 minutes to evaluate the flame retardancy.

Examples 7 to 11 The flame retardant resins were changed to those shown in Table 2. Otherwise, the procedure of Example 3 was followed to obtain a nylon fiber. In Table 2, the silicone 11 is defined as having a molecular weight of 120.
00, R ₂ SiO _1.0 : RSiO _1.5 in a molar ratio of 1:
0.5 represents a silicone resin in which the ratio of the phenyl group to the methyl group of R in the silicone resin is 50:50 in molar ratio. Silicone 19 is a molecular weight of 12000, R ₂ Si
O _1.0 : RSiO _1.5 in a molar ratio of 1: 4, and the ratio of R phenyl group to methyl group in the silicone resin is 6 in a molar ratio.
0:40 indicates a silicone resin. Silicone 22
Is a molecular weight of 40000, R ₂ SiO _1.0 : RSiO
_1.5 indicates a silicone resin having a molar ratio of 1: 4 and a ratio of a phenyl group to a methyl group of R in the silicone resin of 45:55 by a molar ratio. Silicone 24 has a molecular weight of 400
00, R ₂ SiO _1.0 : RSiO _1.5 in a molar ratio of 1:
4. A silicone resin in which the ratio of the phenyl group to the methyl group of R in the silicone resin is 75:25 in molar ratio.
Silicone 27 means a molecular weight of 270000, R ₂ SiO
_1.0 : RSiO _1.5 in a molar ratio of 1: 4, and the ratio of R phenyl group to methyl group in the silicone resin is 60:
The silicone resin which is 40 is shown.

[0028]

[Table 2] As is clear from Table 2, Examples 7-1 which are examples of the present invention.
Sample No. 1 also had excellent yarn quality and flame retardancy.

Example 12 Nylon 6 having a relative viscosity of 2.6 and 6 wt% of a flame-retardant resin added thereto, and nylon 6 having a relative viscosity of 3.1 and nylon MXD6 having a relative viscosity of 2.7 being 50 wt. A side-by-side conjugate fiber consisting of the second nylon blended with% was obtained. At this time, at a melting temperature of 270 ° C., a spinneret having a diameter of 0.3 mm and 12 holes was used.
It is picked up at a speed of 2000 m / min by a heating roller at 0 ° C.
Subsequently, the film was stretched at 150 ° C. between rollers at a speed of 4000 m / min, and then wound up to 50d / 12f.

The fiber obtained had a strength of 3.8 g / d and an elongation of 3
At 3%, no dripping was observed with 3.6 times of flame contact.
When the fiber was treated with boiling water, a good crimp was developed.

[0031]

According to the present invention, it is possible to obtain a flame-retardant polyamide fiber which is difficult to burn, generates no toxic gas even when burned, and does not cause dripping.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shin Serizawa 5-7-1 Shiba, Minato-ku, Tokyo Within NEC Corporation (72) Inventor Keizo Tsujimoto 23 Uji Kozakura, Uji-shi, Kyoto Unitika Ltd. Central Research Laboratory (72) Inventor Shiro Murakami 23 Uji Kozakura, Uji City, Kyoto Unitika Central Research Laboratory F Term (Reference) 4L035 BB56 BB88 BB89 BB91 EE14 LC02 LC08

Claims (1)

[Claims] 1. The flame-retardant composition is a silicone resin having a unit represented by the formula R ₂ SiO _1.0 and a unit represented by the formula RSiO _1.5 , wherein the silicone resin has a weight average molecular weight of 10,000 or more and 270,000. Is less than and
The silicone resin compound in which R is a hydrocarbon group is used in 0.1.
A flame-retardant polyamide fiber containing 1 to 10% by weight.