JPH0512444B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for improving the adhesion of polyester fibers for rubber reinforcement. Polyester fibers, represented by polyethylene terephthalate, have superior properties such as tensile strength, elongation resistance, dimensional stability, and heat resistance compared to other fibers, and are used in rubber for tires, conveyor belts, V-belts, hoses, etc. It is suitable as a reinforcing material. However, it is difficult to firmly adhere polyester fibers and rubber, and this is a major drawback of polyester fibers. Therefore, as a method of improving the adhesion of polyester fibers to rubber, a method of attaching an epoxy compound such as diglycidyl ether of glycerin to the fibers has been proposed. However, adhesion was still not sufficient with just the above-mentioned epoxy compound, and JP-A No. 48-27017, 48-
There are also methods described in publications 41032, 54-112295 and 58-18473. Although these methods are quite effective, there are still issues with adhesion, degree of hardening of the RFL-treated cord,
There is room for improvement in terms of strength. As a result of studies aimed at improving this, the inventors of the present invention found that after adhering an oil composition consisting of an epoxy compound and a specific amine compound to polyester fibers, they were able to adhere uniformly and over a wide area by heat-treating the fibers. It was possible to obtain a polyester fiber with improved properties and less hardening of the treated cord and less loss of strength. That is, the present invention provides polyester fibers with an epoxy compound having at least two epoxy groups in the molecule and a random aliphatic amine such as ethylene oxide and propylene oxide and as an epoxy curing agent in the spinning process and/or drawing process. The present invention relates to a method for improving the adhesion of polyester fibers for rubber reinforcement, characterized in that the adhesion to a rubber composition is improved by adding/or a block adduct. Compared to the case where conventional ethylene oxide adducts and/or propion oxide adducts are attached by the method of the present invention, not only adhesive properties but also heat resistance are better, staining of hot plates and hot rollers during stretching is reduced, Furthermore, since the friction does not increase, thread breakage during drawing is greatly reduced. The present invention will be described more specifically. The polyester fiber used in the present invention contains one or more glycols such as ethylene glycol and propylene glycol, and aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, or one of these derivatives. It means any type of high-molecular polyester fiber obtained by reacting with polyester fibers or more. The most typical of these is high molecular weight polyethylene terephthalate obtained by the reaction of ethylene glycol and terephthalic acid. The epoxy compound used in the present invention is one having at least two or more epoxy groups in its molecule, and specifically includes epichlorohydrin derivatives of polyglycerin such as monoglycerin, di- or triglycerin, sorbitol, and epichlorohydrin of ethylene glycol. derivative, bisphenol A
and epichlorohydrin derivatives of resorcinol. These epoxy compounds of the present invention are used after being dissolved or dispersed in water, an organic solvent such as alcohol, and a spinning oil. The aliphatic amine used in the present invention is a curing accelerator for epoxy compounds, and includes random and/or blocked aliphatic primary amines, secondary amines, and alkanolamines of ethylene oxide and propylene oxide having 4 to 30 carbon atoms. It is an addition. Specifically, primary amines include butylamine, amylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine,
Hexadecylamine, peptadecylamine, octadecylamine, docosylamine, and secondary amines include diethylamine, dipropylamine, diptylamine, diamylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, diundecylamine, diun These include decylamine, ditetradecylamine, dipentadecylamine, and random and/or block adducts of ethylene oxide and propylene oxide, such as alkanolamines such as diethanolamine and triethanolamine. Note that ethylene oxide or propylene oxide may be similarly added to the remaining ethanolic hydroxyl group in a mono- and/or diester of diethanolamine or triethanolamine and a fatty acid. The number of moles of ethylene oxide and propylene oxide added to the aliphatic amine of the present invention is 2 to 40 moles, particularly preferably 4 to 20 moles. Further, as the aliphatic amine, an aliphatic amine having 4 to 20 carbon atoms is particularly desirable. When the number of carbon atoms in the aliphatic amine is 4 or less, the strength of the polyester fiber tends to deteriorate, and especially the strength of the treated cord decreases. In addition, heat resistance is also deteriorated, resulting in increased dirt on the hot plate and hot roller used during stretching, resulting in frequent yarn breakage during stretching. When the number of carbon atoms in the aliphatic amine exceeds 30, the friction becomes significantly high and thread breakage occurs frequently during drawing. Furthermore, the solubility in the spinning oil is also significantly deteriorated. These aliphatic amine compounds of the present invention have water,
It is used by dissolving or dispersing it in an organic solvent such as alcohol and a spinning oil. The epoxy compound and aliphatic amine used in the present invention may be used in combination with a spinning oil, or the epoxy compound and aliphatic amine may be used independently or in a mixture with the spinning oil. The application position may be either undrawn or semi-drawn yarn or drawn yarn. Depending on the case, it may be applied several times during the fiber manufacturing process, such as applying with an undrawn yarn and then applying with a drawn yarn. In the spinning/drawing process of polyester fibers, the undrawn yarn may be wound up and then drawn in a separate step, or the so-called direct spinning/drawing method may be used in which spinning and drawing are performed consecutively. The amount of epoxy compound attached to fibers is 0.1~
5wt%, preferably 0.3-1wt%. If the amount of adhesion is small, sufficient adhesive strength cannot be obtained,
Moreover, if the amount of adhesion is too large, it will fall off onto the hot plate and heat roller, and the thermal decomposition products will increase the friction between the fiber and the metal, causing the running single yarn to break. As a result, the spinning properties and the quality of the yarn deteriorate. The amount of aliphatic amine attached to the fiber is 0.005~
1.5wt%, preferably 0.005-0.5wt%. If the amount of adhesion is small, the reaction of the epoxy compound will be insufficient, and therefore sufficient adhesive strength will not be obtained. If too much is deposited, the strength of the fibers and cord will be reduced and the treated cord will become extremely hard. After treating the polyester fiber with an epoxy compound and an aliphatic amine compound under the above deposition conditions,
Heat treatment is performed at 150°C or higher, preferably 150-260°C.
If heat treated at temperatures below 150℃, sufficient adhesive strength will not be obtained, and if heat treated at temperatures above 260℃,
Fibers may be cut or physical properties may be impaired, which is undesirable. Any heating means can be used, such as a hot plate, hot roller, hot pin, steam heating, dry air heating, etc. In the normal silk spinning process, heat treatment is performed after spinning and drawing or during drawing. Therefore, when applying epoxy compounds and aliphatic amine compounds before this heat treatment process, heat treatment is performed after drawing. It can also be used as Heat treatment time is
The temperature is in the range of 150 to 260°C, preferably 0.03 to 20 seconds. After that, the raw yarn and untreated cord are heated to 70℃ above 30℃.
It may be aged at temperatures below ℃. The present invention is characterized by attaching an epoxy compound and a specific amine compound to polyester fibers, and the combination of these makes it possible to widely and uniformly improve adhesion, and also to harden and strengthen the treated cord. We succeeded in obtaining polyester fibers with little deterioration. Next, the effects of the present invention will be explained using examples. Examples 1 to 5, Comparative Examples 1 to 8 Polyethylene terephthalate was melt-spun, the fineness was 8400D, the number of filaments was 288, and the intrinsic viscosity of the polymer was 0.90 as measured in orthochlorophenol at 25°C.
An undrawn yarn of In the second oiling roll, a 20% oil emulsion containing 10 wt% of the amine compounds shown in Table 3 was added to the spinning oil stock solution, and the oil content was 0.7 wt% (amine compound
0.07wt%) and then immediately
Heat treated at 210℃, stretched at a magnification of 5.6 times, fineness
A drawn yarn of 1500D was obtained. The stretchability during stretching (the number of thread breakages during stretching) and the dirtiness of the hot roller and hot plate were as shown in Table 3. Stretchability is indicated by the number of thread breakages that occur during stretching of polyethylene terephthalate filament equivalent to 1 ton of polymer weight, and staining of the hot roller and hot plate is indicated by the number of thread breakages that occur during stretching of polyethylene terephthalate filament equivalent to 1 ton of polymer weight. It is expressed as the time until the number of yarn breakages exceeds 4 times/ton and becomes frequent. The drawn yarn with a fineness of 1500D was heated at 40℃ and 65%RH.
After leaving the yarn in a temperature-controlled room for a specified period of time to ripen, the yarn is first twisted 40 times/10cm (Z twist), two yarns are doubled, and the final twist is 40 times/10cm (S twist) to make a cord. . Next, RFL processing was performed. The RFL liquid used in the RFL treatment was prepared by aging a mixed liquid (liquid A) consisting of the composition shown in Table 1 at room temperature for 2 hours, and then combining the aged mixed liquid (liquid A) with vinylpyridine-styrene-butadiene. A mixed solution (solution B) obtained by mixing polymalatex (40.5%) and water in the proportions shown in Table 2 was aged for 24 hours.

【table】

[Table] In the RFL treatment of the cord, adjust the amount of RFL liquid that adheres to the cord to be 5%, and apply the RFL liquid to the cord.
After drying at 150°C for 2 minutes, a heat treatment was subsequently performed at 240°C for 1 minute to obtain a treated cord. Five of the obtained treated cords were embedded in unvulcanized rubber mainly composed of natural rubber, and vulcanized at 150° C. for 20 minutes under a pressure of 35 kg/cm ² G. Next, these five treated cords were peeled off at a speed of 300 mm/min, and the force required for the peeling, that is, the peeling force, was measured in kg/cord and evaluated as adhesive strength. The results obtained were as shown in Table 3.

[Table] As is clear from the results shown in Table 3, when the methods of Examples 1 to 5 according to the present invention were used,
Compared to Comparative Examples 1 to 8, it has better adhesion to rubber, reduces stains on the hot plate and hot roller during stretching, significantly extends stain resistance time, and prevents yarn breakage. This has enabled continuous operation, and the resulting product has improved quality with fewer single yarn breakages that can cause yarn breakage. The method for improving the adhesion of polyester fibers for rubber reinforcement according to the present invention not only improves the adhesion of polyester fibers, but also reduces stains on hot plates and hot rollers during stretching, thereby extending continuous operation time. This improves adhesion, operability, and improves product quality by reducing cleaning work for plates, hot rollers, etc., improving operating efficiency, reducing thread breakage caused by dirt on hot plates and hot rollers, and improving product quality. This has the effect of improving both quality at the same time.

Claims (1)

[Claims] 1. Random and/or block adducts of ethylene oxide and propylene oxide of aliphatic amines are added to polyester fibers during the spinning and/or drawing steps, using an epoxy compound having at least two epoxy groups in the molecule and an epoxy curing agent. A method for improving the adhesion of polyester fibers for rubber reinforcement, the method comprising improving the adhesion to a rubber composition.