JP2007284828A - Heat-resistant crosslinked polyester fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester fiber having mechanical properties at middle to high temperature while keeping the characteristics such as dimensional stability, high strength and durability, and also having so excellent heat resistance that no heat fusion occurs at high temperatures. <P>SOLUTION: The heat-resistant crosslinked polyester fiber has a value of the ratio E'<SB>100</SB>/E'<SB>250</SB>of a storage modulus E'<SB>100</SB>at 100°C to a storage modulus E'<SB>250</SB>at 250°C of 4 in a dynamic viscoelasticity measurement. The fiber is provided with a material useful as a belt or carcass member of a tire. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat-resistant crosslinked polyester fiber. Specifically, it has dimensional stability and heat resistance, and more specifically, tire cords, belt materials, canvas, screen bags, etc. that can maintain mechanical properties (storage elastic modulus) from room temperature to medium to high temperatures. The present invention provides a heat resistant cross-linked polyester fiber useful for industrial materials.

  Conventionally, organic fibers such as nylon fibers, rayon fibers, and polyester fibers have been used for tire cords as tire fiber reinforcing materials. When nylon fibers are used for tire cords, although they have high toughness and good adhesion to rubber, they have a relatively large elongation, so that they have poor dimensional stability and are liable to cause a flat spot phenomenon. In addition, when rayon fibers are used for tire cords, the strength is lower than that of the nylon fiber tire cords. For this reason, when used for tire carcass members, the amount used must be increased, resulting in tire weight. There is a disadvantage that increases. Furthermore, there are concerns about the future supply of rayon fiber pulp. For this reason, attention has been paid to the use of polyester fiber having excellent dimensional stability and high strength as a tire cord as a material to compensate for the disadvantages of both.

  In recent years, the need for run-flat tires has increased due to the improvement in safety of automobiles. A run-flat tire is a tire that can travel at a predetermined speed over a certain distance even when the tire punctures during high-speed traveling and the tire internal pressure becomes 0 KPa. This run-flat tire has a side reinforcement type that is reinforced by placing a relatively hard rubber layer with a crescent-shaped cross section on the inner surface of the carcass from the beat part of the tire sidewall to the shoulder area, and the rim part in the tire air chamber. A core type having a ring core made of metal or synthetic resin is known.

  This inner side reinforcement type supports the load by the rigidity inherent to the side wall reinforced with a reinforcing rubber layer when the tire punctures and the air escapes during driving, and it can run for a predetermined distance, but it is flexible at high loads. In the case of a large tire, frictional heat is generated due to contact with the road surface, and the temperature inside the tire may be 200 ° C. or higher, and may be extremely high locally. Thus, the main cause of tire failure is deterioration due to heat generation. Therefore, particularly in the case of run-flat tires, heat-resistant rayon fibers, aramid fibers, steel, and the like are used as carcass members.

  Nylon fiber and polyester fiber are advantageous in terms of price because they can be mass-produced by melt spinning, and are suitable for industrial materials. However, nylon 6 has a melting point of 215 to 220 ° C, nylon 66 has a melting point of 250 to 260 ° C, and polyethylene terephthalate has a melting point of 255 to 260 ° C. It begins to break, the strength, dimensional stability and mechanical properties suddenly drop, and when it generates heat above its melting point, it melts and does not function as a reinforcing material. Similarly, the use of the woven fabric cord was restricted or unsuitable for applications requiring heat resistance.

  As described above, polyester fiber made of copolymerized polyethylene terephthalate is less expensive than rayon fiber. However, if it is provided with functions of heat resistance and mechanical properties, the use is expanded and it is commercially advantageous. Furthermore, a polyethylene naphthalate fiber made of copolymerized polyethylene naphthalate can be useful if it has functions of heat resistance and mechanical properties.

  When the polyester fiber is used for a tire cord, there is a problem that water molecules generated by the neutralization reaction of the amine compound in the rubber with the carboxy end group attack the ester bond of the polyester to cause hydrolysis and deterioration. Various proposals have been made to solve this problem. For example, a method of imparting a polymer comprising acrylic acid and / or methacrylic acid (see Patent Document 1), a method of containing an epoxy compound or a specific diepoxy compound with respect to the polyester and reducing the terminal amount of the carboxy group of the polyester (patent References 2 to 4) and methods for reducing the amount of terminal carboxy groups by incorporating a carbodiimide compound into polyester (see Patent Documents 5 to 9) are disclosed. These methods are effective in suppressing the decrease in strength, fatigue resistance, etc. by reducing the concentration of carboxy groups, but it is difficult to completely eliminate the terminal amount of carboxyl groups. It does not solve the lack of sex.

  Further, as a method for preventing the deterioration of the carcass member in the rubber, a method of protecting by a dipping method after coding (see Patent Documents 10 to 12) is disclosed. However, all of these only prevent and protect the fiber surface from entering the amine compound, and the internal structure has not been modified, and the expected effect is small.

  A fiber cord made of a copolyester excellent in dimensional stability, high strength, durability and the like and a production method thereof (see Patent Documents 13 to 17) are disclosed.

However, although these are tire cords that are achieved by satisfying specific conditions, they cannot be dramatically improved and do not satisfy the heat resistance and mechanical properties as described above.

  On the other hand, a method for improving the heat resistance of polyester fibers by crosslinking (see Patent Document 18) is disclosed. According to this method, it is described that the melt resistance of tobacco can be improved by immersing the yarn immediately after melt spinning in a crosslinking agent and irradiating it with an electron beam while drawing to form a crosslinked polyester fiber. However, this method has problems in operability and stability, and does not maintain the phenomenon of thermal melting at a temperature higher than the melting point of polyester or the mechanical properties.

  A fiber made of a copolyester having excellent dimensional stability, high strength, durability and the like used for a carcass member and a belt material is produced by a known method in the art, but Patent Document 19 is an example of a particularly preferable method. 20 described above.

JP 55-166235 A JP 54-6051 A JP-A-7-166419 JP-A-7-166420 JP 58-23916 A JP-A-5-163612 JP-A-10-168661 JP-A-10-168655 JP 2003-193331 A Japanese Patent Laid-Open No. 2-99667 JP-A-2-127562 JP-A-3-59168 JP 2001-115354 A JP-A-5-71033 JP-A-5-59627 Japanese Patent Laid-Open No. 11-241281 No. 2000-96370 JP-A-6-248521 JP 58-98419 A JP 58-168119 A

  The object of the present invention is to provide excellent dimensional stability, strength, and durability of polyester fibers made of copolymerized polyesters, and in particular, shape at high temperatures while maintaining heat resistance and mechanical properties from room temperature to medium to high temperatures. The object is to obtain a heat-resistant crosslinked polyester fiber having retentivity.

  As a result of intensive studies, the present inventors have found that polyester undrawn yarns and / or drawn yarns obtained by melt spinning a polymer comprising a copolyester are aliphatic having at least two unsaturated bonds and / or Or, after impregnating the alicyclic compound, irradiation with actinic rays was found to achieve the above object, and the present invention was achieved.

  That is, the present invention is as follows.

1. And wherein the value of the ratio E _'100 / E' _{250 250} 'the storage modulus E at ₁₀₀ and 250 ° C.' storage modulus E at at 100 ° C. in dynamic viscoelasticity measurement is at least 10 or less Heat resistant cross-linked polyester fiber.

2. The polyester undrawn yarn and / or drawn yarn obtained by melt spinning the copolyester is impregnated with an aliphatic and / or alicyclic compound having at least two unsaturated bonds, and then irradiated with actinic rays. 2. The heat-resistant crosslinked polyester fiber according to 1 above, obtained by

3. The polyester undrawn yarn and / or drawn yarn obtained by melt spinning the copolyester was treated with a carrier agent, and then impregnated with an aliphatic and / or alicyclic compound having at least two unsaturated bonds. The heat-resistant crosslinked polyester fiber according to 1 above, which is obtained by irradiating with actinic rays.

4). 4. The heat resistant cross-linked polyester fiber according to any one of 1 to 3 above, wherein the actinic ray is an electron beam or a γ ray.

The present invention is the value of the ratio E _'100 / E' _{250 250} 'the storage modulus E at ₁₀₀ and 250 ° C.' storage modulus E at at 100 ° C. in dynamic viscoelasticity measurement is 10 or less The present invention provides a heat-resistant cross-linked polyester fiber characterized by impregnating an aliphatic and / or alicyclic compound having at least two unsaturated bonds into a polyester fiber made of a copolyester, followed by an electron beam , By the crosslinking reaction between the compounds having unsaturated bonds existing in the surface layer of the polyester fiber by irradiation with γ rays and / or the crosslinking reaction between the compounds having unsaturated bonds penetrating into the polyester fiber. As a result of suppressing the fluidity of the crystal part and the crystal part, the mechanical properties can be maintained and the shape can be maintained even at a temperature higher than the melting point temperature.

In general, polyester fibers gradually decrease in mechanical properties (storage elastic modulus E ′) by heating from a temperature of about 100 ° C. This is because the thermal movement of the non-crystalline part is increased by heating, and as the temperature rises further, the crystalline part is easily broken and the mechanical properties are further reduced, and the fluidity is shown accordingly. It is defined as the melting point or melting temperature. When the temperature reaches the melting point or higher, the shape cannot be maintained due to thermal fluidity. However, what is surprising in the present invention is that the storage elastic modulus E ′ is not significantly decreased in the melting point temperature range of 255 to 260 ° C. of the polyester fiber and is not melted at a temperature higher than that. As a result, the shape can be held.
Therefore, the present invention is useful as a run-flat tire cord member that particularly requires heat resistance, mechanical properties, and the like, and is applied to the application of heat resistance to functional fibers other than copolyester fibers by the method of the present invention. Is also possible.

Hereinafter, the present invention will be described in detail.
The present invention is a heat-resistant cross-linked polyester fiber having heat resistance that retains mechanical properties (storage elastic modulus) from room temperature to medium-high temperature, and can retain its shape without being thermally melted even at a temperature equal to or higher than the melting point of the copolyester. heat-resistant crosslinked value of the ratio E _'100 / E' ₂₅₀ of the storage modulus E _'100 and the storage modulus E at 250 ° C.' ₂₅₀ is 10 or less in other words at 100 ° C. in a dynamic viscoelasticity measurement A polyester fiber is provided.

  The copolyester in the present invention, particularly the aromatic copolyester, is a polycondensate of an aromatic dicarboxylic acid component and a diol component, and is not particularly limited, including known ones. Moreover, you may use the unsaturated group containing polyester obtained by reacting with the glycidyl group containing unsaturated compound using the polyester acid terminal. Examples of aromatic dicarboxylic acid components include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyl ether dicarboxylic acid, and 5-sodium sulfone. Examples include phthalic acid. Of these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred. Examples of the diol component include ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, tetramethylene glycol, propylene glycol, octanetylene glycol, decanmethylene glycol, and polyethylene glycol; aliphatic diols such as cyclohexanediol and cyclohexanedimethanol Alicyclic diols; aromatic diols such as naphthalenediol, bisphenol A, resorcin, and the like can be exemplified. Of these, aliphatic diols such as ethylene glycol and trimethylene glycol are preferred. In the aromatic polyester of the present invention, the aromatic dicarboxylic acid component and the diol component are each composed of a single component, and may be a copolyester composed of three or more types. Furthermore, you may blend 2 or more types of aromatic polyester resins.

  Further, in the copolymer polyester, a small amount of other optional polymers, antioxidants, radical scavengers, electrostatic agents, dyeing improvers, dyes, pigments, matting agents, fluorescent whitening agents, inert fine particles, and other Additives may be included. As a method for obtaining an aromatic polyester, it is not necessary to employ special polymerization conditions, and when a reaction product of an aromatic dicarboxylic acid component and / or an ester-forming derivative thereof and a diol component is polycondensed into a polyester. It can be synthesized by any method employed. The polymerization apparatus may be a batch type or a continuous type. Furthermore, after the polyester obtained in the liquid phase polycondensation step is granulated and pre-crystallized, it can also be subjected to solid phase polymerization in an inert gas atmosphere or under reduced pressure vacuum at a temperature below the melting point.

  The polymerization catalyst is not particularly limited as long as it has a desired catalytic activity, but an antimony compound, a titanium compound, a germanium compound, and an aluminum compound are preferably used. When using these catalysts, they may be used alone or in combination of two or more, and the amount used is preferably 0.002 to 0.1 mol% with respect to the aromatic carboxylic acid component constituting the polyester. .

Further, the intrinsic viscosity (IV) of the copolyester in the present invention is preferably 0.6 or more, more preferably 0.8 or more. When IV is 0.6 or less, the intended strength and elastic modulus cannot be obtained.
Moreover, it is preferable that the amount of carboxy terminal groups of aromatic polyester is 50 eq / ton or less, More preferably, it is 30 eq / ton or less. When it exceeds 50 eq / ton, when it is used as a polyester tire cord, durability is deteriorated due to generation of hydrolysis by an amine compound entering from rubber, which is not preferable.

In the present invention, it is possible to employ a method in which the copolymerized polyester is used as a yarn under a conventional melt spinning condition. The taken-up yarn is temporarily wound into an undrawn yarn, or a spin that is continuously drawn after spinning. It can be obtained by, for example, hot drawing by a draw method. In general, the thermal stretching is performed by high-strength one-stage stretching or two-stage or more multi-stage stretching. The heating method includes a method using a superheated roll, superheated steam, a heat plate, a heat box or the like, and is not particularly limited.
As these polyester fibers, those excellent in dimensional stability, high strength and durability manufactured for industrial materials such as a reinforcing material for rubber products such as tires can be preferably used.

  In the present invention, the undrawn yarn and / or drawn yarn of the copolyester fiber obtained as described above is impregnated with an aliphatic and / or alicyclic compound having at least two unsaturated bonds, and the polyester fiber. A polyester fiber having an unsaturated compound on the surface and / or inside thereof is produced batchwise or continuously.

  The aliphatic and / or alicyclic compound having at least two unsaturated bonds used in the present invention is a compound capable of proceeding a radical polymerization reaction by irradiation with ultraviolet rays, electron beams, γ rays, etc., and has an acryloyl group, Compound having two or more unsaturated groups in one molecule consisting of methacryloyl group, itaconoyl group, malenoyl group, fumaroyl group, crotoyl group, acryloylamino group, methacryloylamino group, cinnamoyl group, vinyl group, allyl group, styryl group, etc. And its derivatives. Specific examples include (ethylene, diethylene, triethylene) glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol di Methacrylate, 1,9-nonanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane tri (meth) acrylate, trimethylolmethane (meth) acrylate, tetramethylolmethane tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate Examples include epoxy acrylates that have (meth) acrylated aliphatic or alicyclic compounds having a bisphenol A skeleton in one molecule. The present invention is not limited to such as is.

  The concept for maintaining the storage elastic modulus E 'from the normal temperature to the high temperature range according to the present invention is how to reduce the thermal motion due to the heating temperature of the crystalline part and the amorphous part. In the method according to the present invention, this layer acts as a thermal barrier layer by the cross-linking reaction of the surface layer formed on the polyester fiber, and the unsaturated compound is impregnated even if the unsaturated compound is impregnated even in a small amount inside the polyester fiber. As a result of the cross-linking reaction between each other and the cross-linking reaction between the unsaturated compound in the surface layer and the unsaturated compound inside, the thermal mobility due to heating of the polyester structure (non-crystalline part and crystalline part) is suppressed to a small extent. It is presumed that the storage elastic modulus E ′ is maintained without greatly decreasing. Particularly, the crosslinking reactivity of the unsaturated compound becomes important. In the present invention, an unsaturated compound having 2 or more unsaturated group functional groups, particularly preferably 3 or more unsaturated functional groups, is particularly preferable. A vinyl group-containing (meth) acrylate compound can be preferably used. As a means for advancing the radical reaction of these unsaturated compounds, the aforementioned ultraviolet rays, electron beams, γ rays, etc. can be used, and an electron beam with excellent permeability is used to advance the crosslinking reaction of the impregnated unsaturated compounds. Γ rays can be preferably used. However, depending on the intended use, ultraviolet rays for crosslinking the surface layer can also be used and are not limited. In order to advance the crosslinking reaction with ultraviolet rays, it is preferable to add a radical polymerization initiator, and the type and amount of the radical polymerization initiator are not particularly limited.

  The viscosity of the unsaturated compound used in the present invention is preferably a liquid compound of 5 to 1000 cps at normal temperature (25 ° C.), but it is used if it is in a liquid state when heated to such an extent that the unsaturated compound does not volatilize. It doesn't matter. In particular, it is also preferable to warm the aromatic copolyester near the glass transition point so that the compound is positively impregnated into the polyester fiber.

  The conditions for impregnating the polyester fiber with the unsaturated compound are not particularly limited, but it is preferable to immerse in a warming bath at 30 to 100 ° C. for about 3 to 15 minutes. The compound adhering to the polyester fiber is removed except for the necessary amount by an optional roller, guide bar, etc., and the thickness after crosslinking and curing of the polyester fiber surface layer is 1 μm or more, preferably 4 μm or more. When the thickness of the surface layer is 1 μm or less, it is disadvantageous because the crosslinking density is insufficient and the heat resistance is insufficient.

  Usually, not only polyester unstretched yarn but also stretched yarn has 50% or more amorphous part, and it is the most preferable impregnation method that the unsaturated compound actively penetrates into this amorphous part.

  In the present invention, it is preferable to use a carrier agent in order to further improve the permeability of the unsaturated compound. Specific examples of the carrier agent include carrier agents such as 1,2,4-trichlorobenzene, orthodichlorobenzene, orthophenylphenol, duphenyl, methylnaphthalene, butyl benzoate, dimethyl terephthalate, and methyl salicylate. It is preferable to treat in the previous step of impregnating the compound. The carrier agent treatment is preferably a dipping treatment or a treatment by a spraying method. In the case of a spraying treatment, the treatment is preferably performed by heating at around 100 ° C.

  In order to obtain the heat-resistant crosslinked polyester fiber of the present invention, an impregnated treatment with an unsaturated compound is irradiated with actinic rays such as ultraviolet rays, electron beams, γ rays, etc. to generate radical reactions and crosslinked with actinic rays. Among them, an electron beam or γ-ray having a large irradiation energy transmission power can be preferably used. In the present invention, the irradiation energy of actinic rays is 50 to 10,000 KGy, preferably 1000 to 6000 KGy, and the electron beam is irradiated for crosslinking. When the irradiation energy of the electron beam is 50 KGy or less, the cross-linking reaction does not proceed sufficiently, so that the storage elastic modulus E ′ cannot be maintained, and when it is irradiated with 10000 KGy or more, the formed cross-linking reaction layer becomes brittle and further the polyester is decomposed. It is not preferable because the physical properties of the advance strength deteriorate and the storage elastic modulus E ′ may be difficult to maintain.

The ratio of the storage elastic modulus E′100 at 100 ° C. and the storage elastic modulus E′250 at 250 ° C. in the dynamic viscoelasticity measurement of the heat-resistant crosslinked polyester fiber of the present invention is the value E ′ ₁₀₀ / E ′ ₂₅₀ Is preferably 10 or less. When this ratio is 10 or more, the heat resistance of the polyester fiber is insufficient, and the mechanical properties are lowered and the shape is difficult to maintain. More preferably, the value of the storage elastic modulus E ′ ₁₀₀ / E ′ ₂₅₀ is 5 or less, more preferably 2 or less.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Various measuring instruments and measuring methods are shown below.

(1) Electron beam irradiation Measurement equipment Irradiator Electro curtain laboratory machine Acceleration voltage 165KV
Electron current 5mA
Measurement method A sample obtained by the immersion treatment was set on a tray and irradiated with an electron beam. In addition, the electron beam was irradiated uniformly on the front and back, and the irradiation amount was the sum of them.

(2) Dynamic viscoelasticity measuring device Equipment Rheogel-E4000 Co., Ltd. UBM Measurement condition Frequency 11Hz
Starting temperature 30 ° C
Step temperature 2 ℃
End temperature 300 ℃
Temperature increase rate 5 ℃ / min
Sample width 5mm, length 15mm
Measurement Method After setting the sample on a measuring instrument, the measurement was performed under the measurement conditions. After completion of the measurement, the shape was visually observed.

(3) Intrinsic viscosity The polymer was dissolved in a mixed solvent of parachlorophenol / tetrachloroethane = 3/1 at a concentration of 0.4 g / dl and measured at 30 ° C.

(4) Fineness According to the definition of JIS-L1017, the fineness was measured after being left in a room where the temperature and humidity were controlled at 20 ° C. and 65% RH for 24 hours.

(5) Strength According to the definition of JIS-L1017, the sample was allowed to stand for 24 hours in a temperature and humidity controlled room at 20 ° C. and 65% RH, and then measured with a tensile tester.

(6) Thickness of surface layer It measured using the thickness measuring machine.
The thickness of the surface layer was a value obtained by subtracting the thickness of the polyester fiber before impregnation from the thickness of the impregnated and crosslinked polyester fiber.

(7) Thermal flow start temperature After placing the sample on a hot plate that can be set to a constant temperature for 1 minute, determine whether it is hot melt flowing visually or with a microscope, and determine the temperature at which thermal flow is occurring. (° C).

Example 1
A polyethylene terephthalate chip having an intrinsic viscosity (IV) of 0.95 was adjusted at a spinning temperature of 310 ° C. from a spinneret with a hole number of 336 so that the fineness was 1440 dtex, and was adjusted to 70 ° C. and 1.0 m in a spinning cylinder. The polyester fiber that has been stretch-treated at a draw ratio of 1.6 times is drawn so that the yarn is cooled and solidified with a cooling air of / sec at a spinning speed of 3400 m / min and then the strength is 6.9 cN / dtex. Obtained. Using this polyester fiber, it was immersed in a bath of pentaerythritol tetraacrylate (viscosity 342 cps, 25 ° C.) for 5 minutes at room temperature, then squeezed with a roller, and the resulting impregnated polyester fiber was placed in the required amount tray, and The electron beam was irradiated with a total electron energy of 6000 KGy. It measured by each measuring method using the obtained polyester beam bridge | crosslinked polyester fiber.

(Example 2)
It processed and measured by the method similar to Example 1 except having heated and processed the bath temperature which consists of pentaerythritol tetraacrylate at 70 degreeC.

(Example 3)
The polyester fiber used in Example 1 was preliminarily treated with a chlorobenzene-based carrier agent heated at 100 ° C. for 5 minutes, and then treated and measured in the same manner as in Example 2.

Example 4
An impregnated polyester fiber was obtained in the same manner as in Example 1 except that pentaerythritol tetraacrylate was switched to trimethylolpropane triacrylate, and an electron beam crosslinked polyester fiber obtained by irradiating an electron beam in the same manner as in Example 1. It measured by each measuring method using.

(Example 5)
In the same manner as in Example 3, after immersion treatment with a carrier agent, the bath temperature composed of trimethylolpropane triacrylate was heated to 70 ° C. and treated in the same manner as in Example 3.

(Comparative Example 1)
The polyester fiber used in Example 1 was measured for the fiber state without compound impregnation treatment or electron beam crosslinking.

(Comparative Example 2)
A polyethylene terephthalate chip having an intrinsic viscosity (IV) of 1.05 was supplied to a melt extruder, and 0.7 weight of diallyl monoglycidyl isocyanurate heated to 50 to 60 ° C. at the same time from the extruder inlet with respect to polyethylene terephthalate. % Was added at a constant flow rate. The amount of the kneaded polymer is adjusted at a spinning temperature of 310 ° C. from a spinneret with a hole number of 336 so that the fineness is 1440 dtex, and cooled and solidified with a cooling air of 70 ° C. and 1.0 m / sec in the spinning cylinder. After the caulked yarn was taken up at a spinning speed of 3400 m / min, a polyester fiber stretched at a draw ratio of 1.6 times was obtained so that the strength was 6.5 cN / dtex.
The polyester fiber obtained was put in a required amount tray and irradiated with an electron beam with a total electron energy of 1000 KGy. It measured by each measuring method using the obtained polyester beam bridge | crosslinked polyester fiber.

  As is clear from Table 1 and FIGS. 1 and 2, the polyester fibers obtained in Examples 1 to 5 retain the storage viscoelastic modulus E ′. Furthermore, even when the heat flow start temperature was 340 ° C., the polyester fiber was excellent in heat resistance with no heat flow and shape.

On the other hand, as shown in Table 1 and FIG. 3, the non-crosslinked polyester fiber obtained in Comparative Example 1 has a storage elastic modulus E ′ that gradually decreases from 100 ° C. or higher. Mechanical properties are not maintained. Further, the heat flow starting temperature flowed around 255 ° C. near the melting point, and the shape was not maintained.
Further, as shown in Table 1 and FIG. 4, the polyester fiber obtained in Comparative Example 2 has a storage elastic modulus E ′ that gradually decreases from 100 ° C. or higher, and the mechanical properties are maintained at a melting point and a temperature higher than the melting point. Not. Moreover, the heat flow start temperature flowed in the vicinity of the melting point of 264 ° C. and did not retain the shape.

The value of the ratio E _'100 / E' _{250 250} 'the storage modulus E at ₁₀₀ and 250 ° C.' storage modulus E at at 100 ° C. in dynamic viscoelasticity measurement is 10 or less heat resistance of the present invention The cross-linked polyester fiber is capable of maintaining the mechanical properties and maintaining the shape even at a temperature higher than the melting point temperature, and impregnating with an aliphatic and / or alicyclic compound having at least two unsaturated bonds. It is obtained by irradiating with actinic rays. This method can be used not only for fibers made of copolyester but also for other natural fibers and organic fibers. It is also expected to be used in other fields where heat resistance and dimensional stability are required, such as film and engineering plastics.

It is the storage elastic modulus E ′ of the heat-resistant crosslinked polyester fiber obtained in Example 1. It is the storage elastic modulus E 'of the heat-resistant crosslinked polyester fiber obtained in Example 4. It is the storage elastic modulus E ′ of the polyester fiber of Comparative Example 1. It is the storage elastic modulus E ′ of the cross-linked polyester fiber of Comparative Example 2.

Claims (4)

Wherein the value of the ratio E _'100 / E' _{250 250} 'the storage modulus E at ₁₀₀ and 250 ° C.' storage modulus E at at 100 ° C. is 10 or less in the measurement of dynamic viscoelasticity Heat resistant cross-linked polyester fiber.   The polyester undrawn yarn and / or drawn yarn obtained by melt spinning the copolyester is impregnated with an aliphatic and / or alicyclic compound having at least two unsaturated bonds, and then irradiated with actinic rays. The heat-resistant crosslinked polyester fiber according to claim 1, which is obtained by   The polyester undrawn yarn and / or drawn yarn obtained by melt spinning the copolyester was treated with a carrier agent, and then impregnated with an aliphatic and / or alicyclic compound having at least two unsaturated bonds. The heat-resistant cross-linked polyester fiber according to claim 1 obtained by irradiating with actinic rays.   4. The heat resistant cross-linked polyester fiber according to claim 1, wherein the actinic ray is an electron beam or a gamma ray.

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