JP2006307382A - Heat-resistant cross-linked polyester fiber cord - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide polyester fiber cords which maintain characteristics such as dimensional stability, high strength and durability, are simultaneously thermally not melted at high temperature, and have excellent heat resistance, and to provide a material useful as the belt and carcass member of a tire from the fiber cords. <P>SOLUTION: The heat-resistant cross-linked polyester fiber cords which have excellent heat resistance are characterized by (1) immersing polyester fibers comprising a copolyester in a compound having at least two unsaturated groups, irradiating the treated fibers with electron beams or γ-rays, and then processing the treated fibers into the cords, or (2) immersing polyester fiber cords preliminarily treated with a carrier agent in a compound having at least two unsaturated groups, and then irradiating the treated fiber cords with electron beams or γ-rays. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat-resistant crosslinked polyester fiber cord. More specifically, the present invention provides a heat-resistant cross-linked polyester fiber cord having dimensional stability, high strength, durability, etc., excellent in heat resistance, and useful for industrial materials such as tire cords and belt materials. .

  Conventionally, organic fibers such as nylon fibers, rayon fibers, and polyester fibers have been used for cords as tire fiber reinforcements. 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.

  On the other hand, when nylon fiber or polyester fiber is used for a carcass member of a run-flat tire, heat begins to break at an adhesive interface with the tire rubber due to heat generation near 200 ° C., and strength and dimensional stability rapidly decrease. When heat generation at a temperature of 0 ° C. or higher occurs, the melting point of the nylon fiber or polyester fiber is exceeded, so that heat melting occurs and the role as a reinforcing material cannot be maintained. Therefore, it has been restricted or unsuitable for applications requiring heat resistance as well as belts and other textile cords as well as carcass members for run-flat tires.

  Polyester fibers made of copolymerized polyethylene terephthalate are less expensive than rayon fibers, and it is commercially advantageous if they are given a heat-resistant function. Furthermore, if the application of heat-resistant function is applied to polyethylene naphthalate fibers and nylon fibers made of copolymerized polyethylene naphthalate, the usage can be expanded and useful.

  When the above polyester fiber is used for a tire cord, the water molecule generated by the neutralization reaction of the amine compound in the rubber with the carboxy end group is deteriorated by attacking the ester bond of the polyester and causing hydrolysis. In order to solve this problem, various proposals have been made to solve at the polyester fiber stage. 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 and fatigue resistance by reducing the concentration of carboxy end groups, but it is difficult to completely eliminate the amount of carboxy group ends. It does not solve the lack of heat resistance.

  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 polyester fiber cord made of a copolyester capable of obtaining dimensional stability, durability, thermal characteristics, and the like, and a production method thereof (see Patent Documents 13 to 17) are disclosed.

  However, although all of these are tire cords that can achieve the purpose by satisfying specific conditions, they cannot be dramatically improved, and the heat resistance as described above cannot be obtained.

  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-proofing property of tobacco can be improved by immersing the yarn immediately after melt spinning of the polyester in a cross-linking agent, irradiating with an electron beam while drawing and forming a cross-linked polyester fiber. However, this method has problems in operability and stability, and does not solve the phenomenon of thermal melting at a temperature higher than the melting point of polyester, and cannot be said to have been imparted with heat resistance at high temperatures.

  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 manufactured by a known method in the art, but Patent Document 19, The method of 20 description is mentioned.

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 JP 2000-96370 A JP-A-6-248521 JP 58-98419 A JP 59-168119 A

  The object of the present invention is to impart heat resistance at a temperature higher than the melting point, which is a problem of polyester fibers, while maintaining excellent dimensional stability, high strength, and durability of polyester fibers made of copolymerized polyester, and heat melting. An object of the present invention is to obtain a polyester fiber cord excellent in heat resistance that can maintain its form without being formed.

As a result of extensive research, the present inventors have (1) impregnated a polyester fiber of a drawn yarn obtained by melt spinning a polymer comprising a copolyester with a compound having at least two unsaturated bonds. Irradiated with actinic rays to form heat-resistant crosslinked polyester fiber, and then twisted to form a cord. (2) After treating the polyester fiber cord with a carrier agent in advance, impregnation treatment with a compound having at least two unsaturated bonds Then, it was found that the above-mentioned object was achieved by irradiating actinic rays to form a cord, and reached the present invention.

That is, the present invention is achieved by the following.
1. A heat-resistant cross-linked polyester characterized in that a polyester fiber obtained by melt spinning a copolyester is impregnated into a compound having at least two unsaturated bonds and irradiated with actinic rays to form a fiber cord. Fiber cord.
2. A heat-resistant cross-linked polyester fiber cord obtained by impregnating a polyester fiber cord made of a copolyester into a compound having at least two unsaturated bonds and irradiating with actinic rays.
3. 3. The heat-resistant cross-linking type according to the above 1 or 2, wherein the polyester fiber and / or polyester fiber cord is treated with a carrier agent in advance, and then impregnated with a compound having at least two unsaturated bonds and irradiated with actinic rays. Polyester fiber cord.
4). 3. The polyester fiber cord surface layer obtained by impregnation has a compound layer having at least two unsaturated bonds, and the thickness of the layer is at least 1 μm or more. Heat resistant cross-linked polyester fiber cord.
5. The absorbance ratio of the absorbance of the compound and the absorbance of the polyester determined from the IR spectrum of the polyester fiber cord obtained by impregnation is at least,
Polyester fiber cord surface layer: 0.1 or more Polyester fiber cord inside: 0.1 or more The heat-resistant crosslinked polyester fiber cord according to any one of 1 to 4 above.
6). 6. The heat-resistant cross-linked polyester fiber cord according to any one of 1 to 5 above, wherein the actinic ray is an electron beam or γ-ray.

  In forming a tire cord using the polyester fiber comprising the copolymerized polyester of the present invention, the compound having at least two unsaturated bonds is impregnated and irradiated with actinic rays such as an electron beam and γ-ray. A cross-linking reaction occurs between the surface layer and the compound existing in the surface layer and the inside thereof, and thermal melting at a temperature higher than or equal to the melting temperature of the polyester fiber can be suppressed.

  As a result, the form as a tire cord can be maintained. Furthermore, it is surprising that the shape can be maintained without being melted at a temperature of 300 ° C. or higher. The present invention is useful as a carcass member of a run-flat tire that has been difficult to use due to insufficient heat resistance, and can also be applied to impart heat resistance to nylon fibers other than fibers made of a copolyester.

Hereinafter, the present invention will be described in detail.
The present invention is a heat-resistant material that can maintain its shape without heat melting even at a high temperature, particularly at a melting point of the copolyester or higher, preferably 265 ° C. or higher, more preferably 280 ° C. or higher, more preferably 300 ° C. or higher. An improved heat-resistant cross-linked polyester fiber cord 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. 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 aromatic copolyester, a small amount of any other polymer, antioxidant, radical scavenger, electrostatic agent, dyeing improver, dye, pigment, matting agent, fluorescent whitening agent, inert fine particles Other additives may be contained. 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.

Further, in the present invention, a method can be adopted in which the copolymerized polyester is used as a yarn under conventional melt spinning conditions. It can be obtained by, for example, hot drawing by a spin 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, a heat-resistant crosslinked fiber cord can be obtained by the following method. That is, (1) a polyester fiber having at least two unsaturated bonds impregnated with a drawn fiber of a copolymerized polyester fiber obtained by melt spinning, and a polyester fiber having a compound on the surface and inside of the polyester fiber; After that, it is irradiated with actinic rays to form a cross-linked polyester fiber, and then used as a cord with a ring twisting machine or a straight twisting machine. (2) Already converted into a cord with a ring twisting machine or a straight twisting machine using polyester fiber There is a method in which a compound having at least two unsaturated bonds is impregnated into the polyester fiber and the polyester fiber is similarly present on the surface and inside of the polyester fiber, and then irradiated with actinic rays to form a crosslinked polyester fiber cord. Or it manufactures continuously.

  In this invention, it can be set as a raw cord by a ring twisting machine or a straight twisting machine by a conventional method. Raw cords in the ordinary method are twisted 10 to 100 times per 10 cm (bottom twist), then combined into a plurality of yarns, and twisted 10 to 100 times per 10 cm (upper twist) in the opposite direction. To do.

  The compound having at least two unsaturated bonds used in the present invention is a compound capable of proceeding radical polymerization reaction by irradiation with electron beam or γ-ray, and is acryloyl group, methacryloyl group, itaconoyl group, malenoyl group, fumaroyl group. A compound having two or more unsaturated groups in one molecule consisting of a crotoyl group, an acryloylamino group, a methacryloylamino group, a cinnamoyl group, a vinyl group, an allyl group, a styryl group, and the like, and more specifically, Examples include compounds having a cyanuric acid or isocyanurate ring in one molecule and derivatives thereof, such as triallyl isocyanurate, triallyl cyanurate, diallyl methyl isocyanurate, diallyl ethyl isocyanurate, diallyl decyl isocyanurate, diallyl dodecyl iso Anurate, diallyl myristyl isocyanurate, diallyl cetyl isocyanurate, diallyl stearyl isocyanurate, ethyl bis diallyl isocyanurate, tetramethylene bis diallyl isocyanurate, hexamethylene bis diallyl isocyanurate, decamethylene bis diallyl isocyanurate, oxydiethyl bis diallyl isocyanurate , Dioxytriethylenebisdiallyl isocyanurate, diallyl methyl cyanurate, diallyl ethyl cyanurate, diallyl decyl cyanurate, xylene bis diallyl isocyanurate, 1,3-diallyl-5- (2,3-epoxypropan-1-yl ) -1,3,5-triazine-2,4,6 (1H, 3H5H) -trione, tris (2-hydroxyethyl) isocyanane Examples include compounds such as rate triacrylate, and any compound having an unsaturated group in a compound having a cyanuric acid or isocyanurate ring in the molecule and a derivative thereof can be used without particular limitation. , Triallyl isocyanurate, 1,3-diallyl-5- (2,3-epoxypropan-1-yl) -1,3,5-triazine-2,4,6 (1H, 3H5H) -trione, tris ( 2-Hydroxyethyl) isocyanocyanurate triacrylate or the like can be preferably used, and two or more kinds may be mixed if necessary.

  A preferable viscosity of the compound used in the present invention can be used as long as it is in the range of 5 to 150 mPa · s at room temperature (25 ° C.), but it may be heated to such an extent that the compound does not volatilize. Furthermore, it can be preferably recommended that the compound is positively impregnated inside the polyester fiber and fiber cord by heating to the vicinity of the glass transition point of the aromatic copolyester.

  The conditions for impregnating the polyester fiber and fiber cord with the above compound are not particularly limited, but in order to allow the compound to penetrate into the polyester fiber and fiber cord, the heating bath at 30 to 100 ° C. is about 3 to 15 minutes. It is preferable to immerse. When a low viscosity compound is used at room temperature (25 ° C.), it can penetrate into the interior in about 3 to 5 minutes, and the compound attached to the polyester fiber and fiber cord is required by any roller or guide bar. The thickness after removal of the polyester fiber and the fiber cord surface layer after crosslinking and curing is preferably 1 μm or more, and 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.

  The presence of the polyester fiber and the compound contained in the fiber cord thus obtained can be confirmed by the absorbance ratio obtained from the absorbance of the polyester and the absorbance of the compound obtained from the IR spectrum by the IR spectrum analysis measurement method. If the absorbance ratio is 0.1 or more, the compound is present and crosslinkability is obtained. If it is 0.1 or less, sufficient crosslinkability cannot be obtained, so that the heat resistance is insufficient, which is not preferable. Usually, even 50% or more of an amorphous portion is present even in a drawn fiber of polyester fiber, and therefore, the most preferable impregnation method is that the compound actively penetrates into this amorphous portion.

  In the present invention, the use of a carrier agent can be preferably recommended in order to further improve the permeability when the compound is impregnated into the already corded polyester fiber. Overlapping portions caused by twisting of the polyester fiber tend to be insufficient in the permeability of the compound, and as a result, the heat resistance may be insufficient due to insufficient crosslinking due to the insufficient permeability of the compound. There are methods such as increasing the impregnation time or positively heating, but this is not industrially preferable.

  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. . 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 cord of the present invention, the compound impregnated with the compound is irradiated with actinic rays such as ultraviolet rays, electron beams, and γ rays to cause radical reaction to be crosslinked with active 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 100 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 crosslinking reaction does not proceed sufficiently, and irradiation with 10000 KGy or more is not preferable because the polyester may be decomposed and the strength properties may be lowered. Further, if the irradiation amount is excessive, the compound layer becomes brittle and interfacial peeling occurs, which is not preferable.

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 trace 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. At the end of the measurement, the shape was visually observed.
(3) Linkam test Measuring instrument Equipment Microscope cooling and heating equipment “TH600” (manufactured by Linkome)
Set temperature 300 ℃
Measurement Method An evaluation sample was placed on a slide glass and the molten state of the sample was visually observed.
(4) Absorbance ratio Measuring instrument FT-IR analyzer FTS7000 manufactured by Digilab
ATR attachment Thermo Sptra-Tech
Thunderdome (IRE: Ge)
Detector DTFS, resolution 8 cm ^-1 integration count 128 times Infrared microscope Digilab UMA600
Measuring method The surface layer of the necessary sample and the inside after removing the surface layer were taken out, molded on a film by applying pressure, placed on a Kbr plate, and the IR spectrum was measured by a microscopic transmission method.
From the obtained spectra, the ratio of the absorbance of 1690 cm ⁻¹ (absorption of isocyanurate ring) to the absorbance of 1720 cm ⁻¹ (PET ester bond) was determined by the following equation.
Absorbance ratio = ^1. Absorbance at 1690.sup.- ¹ cm / ^1. Absorbance at 1720.sup.- ¹ cm The respective absorbances were taken from the valley near 1880 cm.sup.- ¹ and the height from the baseline at 1640 cm.sup.- ¹ .
(5) 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.
(6) 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.
(7) Strong Elongation According to the definition of JIS-L1017, after being left in a room where the temperature and humidity were controlled at 20 ° C. and 65% RH for 24 hours, the strength, elongation at break and intermediate elongation were measured with a tensile tester.
(8) Thickness of surface layer It measured using the thickness measuring machine.
The surface layer thickness was a value obtained by subtracting the thickness of the polyester fiber cord before impregnation from the thickness of the impregnated and crosslinked polyester fiber cord.

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 having a hole number of 336 so that the fineness would be 1440 dtex, and 70 ° C. and 1.0 m in a spinning cylinder. After the yarn cooled and solidified with a cooling air of / sec is taken up at a spinning speed of 3400 m / min, the draw ratio is 1. so that the strength continues to be 6.9 cN / dtex and the intermediate elongation is 5.5%. A polyester fiber stretched 6 times was obtained. Using this polyester fiber, it was immersed in a bath made of triallyl isocyanurate (viscosity 80 to 110 mPa · s) at room temperature for 5 minutes, then squeezed with a roller, and the required amount of the resulting triallyl isocyanurate-impregnated polyester fiber was obtained. Was placed in a tray and irradiated with an electron beam with an electron energy of 6000 KGy. The obtained electron beam cross-linked polyester fiber yarn was measured by each measuring method. Next, two yarns obtained were twisted together to obtain a raw cord with 1440 dtex / 2 and a twist number of 43 × 43 (t / 10 cm), and measurement was performed by each measurement method.

(Example 2)
The polyester fiber treated and crosslinked in the same manner as in Example 1 was subjected to only necessary measurements, except that the immersion condition with triallyl isocyanurate was a heated 70 ° C. bath. Next, measurement was performed using raw cords in the same manner as in Example 1.

(Example 3)
Triallyl isocyanurate to 1,3-diallyl-5- (2,3-epoxypropan-1-yl) -1,3,5-triazine-2,4,6 (1H, 3H5H) -trione (product name diallyl) Except for processing to a 70 ° C. heating bath made of monoglycidyl isocyanuric acid), the same method as in Example 1 was used to obtain a crosslinked polyester fiber, and then only necessary measurements were performed. Next, measurement was performed using raw cords in the same manner as in Example 1.

Example 4
Except having processed into the 30 degreeC heating bath which consists of a tris (2-hydroxyethyl) isocyanocyanurate triacrylate, after obtaining the bridge | crosslinking-type polyester fiber by the method similar to Example 1, only the required measurement was performed. Next, measurement was performed using raw cords in the same manner as in Example 1.

(Example 5)
Twisting the two polyester fibers used in Example 1, 1440 dtex / 2, twisted 43 × 43 (t / 10 cm) raw cord was immersed in a chlorobenzene-based carrier agent heated in advance at 100 ° C. for 5 minutes, Then, it was immersed for 5 minutes in the 70 degreeC heating bath triallyl isocyanurate, and the electron energy was irradiated with electron energy 6000KGy. The obtained electron beam cross-linked polyester fiber cord was measured by each measuring method.

  As is clear from Table 1 and FIG. 4, the polyester fiber cords obtained in Examples 1 to 5 are polyester fiber cords that retain their shape without being melted even at a high temperature of 300 ° C. and have excellent heat resistance. It was.

(Comparative Example 1)
The polyester fiber raw cords used in Example 5 were subjected to various measurements without compound impregnation and electron beam crosslinking.

  As shown in Table 1 and FIG. 5, the polyester was melted at a melting point of 255 ° C. and did not retain its shape.

  The method of improving heat resistance by impregnating a compound having at least two unsaturated bonds of the present invention and irradiating actinic rays to cause a crosslinking reaction is not limited to fiber cords made of copolymerized polyesters, but other fibers. It can be used to improve the heat resistance of cords made of It is also expected to be used in other fields where heat resistance and dimensional stability are required, such as film and engineering plastics.

IR spectrum data of the surface of the polyester fiber before the process used in Examples 1-5 and Comparative Example 1. IR spectrum data of the surface of the heat resistant cross-linked polyester fiber cord obtained in Example 1. IR spectrum data inside the heat-resistant crosslinked polyester fiber cord obtained in Example 1. It is the dynamic viscoelasticity of the heat-resistant crosslinked polyester fiber cord obtained in Example 1. It is the dynamic viscoelasticity of the polyester fiber cord of Comparative Example 1.

Claims (7)

  A heat-resistant cross-linked polyester characterized in that a polyester fiber obtained by melt spinning a copolyester is impregnated into a compound having at least two unsaturated bonds and irradiated with actinic rays to form a fiber cord. Fiber cord.   A heat-resistant cross-linked polyester fiber cord obtained by impregnating a polyester fiber cord made of a copolyester into a compound having at least two unsaturated bonds and irradiating with actinic rays.   3. The heat-resistant crosslinking according to claim 1, wherein the polyester fiber and / or the polyester fiber cord is previously treated with a carrier agent, and then impregnated with a compound having at least two unsaturated bonds and irradiated with actinic rays. Type polyester fiber cord.   The polyester fiber cord surface layer obtained by impregnation has a compound layer having at least two unsaturated bonds, and the thickness of the layer is at least 1 µm or more. Heat resistant cross-linked polyester fiber cord. The absorbance ratio of the absorbance of the compound and the absorbance of the polyester determined from the IR spectrum of the polyester fiber cord obtained by impregnation is at least,
Polyester fiber cord surface layer: 0.1 or more Polyester fiber cord interior: 0.1 or more The heat-resistant crosslinked polyester fiber cord according to claim 1, wherein:   6. The heat resistant cross-linked polyester fiber cord according to claim 1, wherein the actinic ray is an electron beam or a gamma ray.   A pneumatic radial tire using the heat-resistant crosslinked polyester fiber cord according to claim 1 as a carcass material.

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