TWI555889B - Polyester fiber for rubber reinforcing and its manufacturing method - Google Patents

Description

Rubber fiber for reinforcing rubber and manufacturing method thereof

The present invention relates to a rubber reinforcing fiber, and more particularly to a rubber reinforcing polyester fiber which is excellent in adhesion after high-temperature dynamic fatigue and a method for producing the same.

Polyester fibers represented by polyethylene terephthalate and its derivatives have excellent mechanical properties, physical and chemical properties, and are industrially produced in large quantities. Their uses are diversified by industrial materials. And is a useful fiber. In particular, a polyester fiber having high strength and excellent dimensional stability is a material which is very suitable as a reinforcing material for a rubber material such as a tire, a conveyor belt, a hose, etc., and more and more recently, it is required to have high performance. For example, in the case of a conveyor belt rope such as a V-belt, it is necessary to have higher fatigue resistance when it is used as a high modulus or even a large high-load coated conveyor belt rope. On the other hand, when used in tire cord applications, in order to improve the productivity of the tire during molding, and to reduce the shrinkage or to improve the comfort of riding comfort, and in the use of large tires, it is necessary to improve fatigue resistance. Sex and so on.

However, the polyester fiber has high strength, but has a low modulus and a large shrinkage ratio, as compared with the other fibers of the general-purpose rubber reinforcing fiber. Then, in order to increase the modulus of the polyester fiber and to reduce the shrinkage rate, a method of extending the unoriented yarn with a high orientation as a starting point (Patent Document 1 or Patent Document 2) is employed. Further to improve the spinnability, Improvements in the spinning oil agent and the like are now continuing (Patent Document 3, etc.).

Further, since the polyester fiber is composed of a molecular structure having a low polarity, there is basically a problem in adhesion to rubber. Therefore, resorcinol-fomalin-latex (RFL)-based adhesives are widely used as adhesives for polyester fibers and rubber, and further improvements are under review. A two-bath treatment method in which fibers are pretreated with an adhesion promoter prior to treatment with an RFL-based adhesive is generally widely used. In other respects, as for the method for improving the two-bath type treatment method on the side of the polyester fiber, a pretreated polyester fiber in which an adhesion promoter is added in advance in the spinning step is known. (for example, Patent Document 4 or Patent Document 5)

However, even with any of these methods, the polyester fiber obtained by the conventional method has a problem of insufficient performance in terms of adhesion after high-temperature dynamic fatigue in a rubber required for a conveyor belt or the like.

Patent Document 1: Japanese Laid-Open Patent Publication No. 53-58032

Patent Document 2: Japanese Laid-Open Patent Publication No. SHO 57-154410

Patent Document 3: Japanese Laid-Open Patent Publication No. 7-70819

Patent Document 4: Japanese Patent Laid-Open No. 52-96234

Patent Document 5: Japanese Laid-Open Patent Publication No. 2000-355875

The present invention provides a rubber reinforcing polyester fiber which is excellent in adhesion to high-temperature dynamic fatigue when it is bonded to rubber; Production method.

The polyester fiber for rubber reinforcement according to the present invention is a fiber composed of polyester having ethylene terephthalate as a main repeating unit and having an intrinsic viscosity of 0.85 or more, and is characterized by a terminal carboxyl group amount in the fiber. The surface treatment agent having an epoxy group is attached to the surface of the fiber with a long period of 9 to 12 nm as measured by X-ray small angle diffraction of 20 eq/ton or more.

Further, the amount of terminal carboxyl groups on the surface of the fiber is 10 equivalent/ton or less, or the crystal grain size in the transverse direction of the fiber is 35 to 80 nm ² , and the amount of terminal methyl groups in the fiber is 2 equivalent/ton or less, and oxidation in the fiber The titanium content is 0.05 to 3% by weight, and the epoxy index of the fiber surface is preferably 1.0 × 10 ^-3 equivalent / kg or less.

Another method for producing a polyester fiber according to the present invention is characterized in that a polyethylene terephthalate polymer having an intrinsic viscosity of 0.9 or more and a terminal carboxyl group content of 15 equivalents/ton or more is melt-extruded, and an alkali is added. After the spinning oil of the hardening catalyst, it is extracted at a speed of 2000 to 6000 m/min, and then extended, and then a finishing oil containing an epoxy compound is added to perform a ripening treatment.

Further, it is preferred that the ripening treatment temperature is in the range of 20 to 50 ° C or the ripening treatment time is 50 hours or more, and the epoxy curing catalyst is preferably an amine compound.

According to the present invention, it is possible to provide a polyester fiber for rubber reinforcement which is excellent in adhesion after high-temperature dynamic fatigue in the case of adhesion to rubber, and a method for producing the same.

The polyester fiber for rubber reinforcement of the present invention is a fiber composed of polyester having ethylene terephthalate as a main repeating unit. The content of the main repeating unit of the polyester is preferably 80 mol% or more based on the total dicarboxylic acid component constituting the polyester. It is particularly preferable to contain a polyester of 90 mol% or more. Further, when the content in the polyester polymer is small, a copolymer containing an appropriate third component may be used.

Further, the inherent viscosity of the polyester fiber must be 0.85 or more, preferably 1.10 or less. Further, it is preferably in the range of 0.89 to 1.05, particularly in the range of 0.90 to 1.00. If the intrinsic viscosity is less than 0.85, the strength of the polyester fiber is insufficient, and in particular, the rubber vulcanization step cannot sufficiently suppress the strength reduction.

Further, the long period of the rubber reinforcing polyester fiber of the present invention measured by X-ray small angle diffraction must be 9 to 12 nm. Here, the long period measured by the X-ray small angle diffraction means the interval between the crystal and the crystal in the polyester polymer in the longitudinal direction of the fiber (the direction in which the fiber is spun). The polyester fiber for rubber reinforcement of the present invention exhibits a short interval between crystals in this long period. As a result, the number of tie molecules directly bonded to crystals increases, and as a rubber reinforcing fiber, the strength maintenance rate of the fibers in the rubber can be maintained at a high value. . Therefore, as described later, even when the amount of terminal carboxyl groups in the fiber polymer is larger than in the related art, sufficient durability can be obtained by surface treatment such as epoxy treatment. In addition, by setting the long period of the fiber to such a range, the physical properties of the fiber can be made into a high modulus, and a low shrinkage ratio is suitable for the physical properties of the fiber for rubber reinforcement.

In order to set the long period as described above to 12 nm or less, it can be achieved by high speed spinning, and in the case of low speed spinning, the long period value becomes large. In addition, high-speed spinning is limited, and the long period is limited to a range of 9 nm. Further, the long period system measured by X-ray small angle diffraction is preferably in the range of 10 nm to 11 nm.

Further, the polyester fiber for rubber reinforcement of the present invention preferably has a crystal grain size in the range of 35 to 80 nm ² in the transverse direction of the fiber (direction perpendicular to the direction in which the fiber is spun). In the polyester fiber of the present invention, the long period of the crystal spacing of the longitudinal axis of the fiber is as low as 12 nm or less, and in order to form a high-strength fiber, a certain crystal size is also necessary. In the present invention, the crystal grain in the transverse direction of the fiber is required. The diameter system is preferably grown to 35 nm ² or more. However, if the crystal grain size is too large, the fibers become rigid and the fatigue resistance is lowered, so that it is preferably 80 nm ² or less. Further, the crystal grain size in the transverse direction of the fiber is preferably in the range of 40 to 70 nm ² . In this way, since the crystal grows in the direction of the transverse axis of the fiber, the stretched molecules are easily developed in the direction of the transverse axis of the fiber. Therefore, a three-dimensional structure is formed in the longitudinal and lateral directions of the fiber, and it is particularly suitable for the rubber reinforcing aspect as in the present invention. Fiber. Further, with this three-dimensional structure, the fiber loss coefficient Tan δ becomes low. As a result, the amount of heat generated under the repeated application of stress can be suppressed, and the subsequent performance after repeated stress application can be kept high, and it is particularly suitable for use in rubber reinforcement applications.

Further, in the polyester fiber for rubber reinforcement of the present invention, the amount of the carboxyl group of the entire polymer must be 20 equivalents/ton or more, and a surface treatment agent having an epoxy group must be adhered to the surface of the fiber. More preferably, in order to improve the heat deterioration resistance, the polyester fiber for rubber reinforcement used in a high-load environment such as high temperature or high vibration is preferably kept at a level of 15 equivalents/ton or less. Maintaining a condition below 10 eq/ton is a common and common approach. However, in the case of the polyester reinforcing polyester fiber, in addition to maintaining the strength of the fiber, the necessity of maintaining the adhesiveness with the rubber is also high, as measured by the X-ray small angle diffraction of the polyester fiber of the present invention. The inventors of the present invention found these phenomena as long as the long period is as low as 9 to 12 nm and the amount of the carboxyl group is 20 equivalent/ton or more in the case of performing epoxy treatment on the surface. Further, the amount of the carboxyl group in the polymer is preferably such that the upper limit of the amount of terminal carboxyl groups is 40 equivalents/ton or less, even 30 equivalents/ton or less, particularly preferably in the range of 21 to 25 equivalents/ton.

A surface treatment agent having an epoxy group is attached to the surface of the polyester fiber for rubber reinforcement of the present invention. Here, the surface treatment agent is preferably an epoxy compound containing one or a mixture of two or more kinds of epoxy compounds having two or more epoxy groups in one molecule. More specifically, it is preferably a halogen-containing epoxy group, and examples thereof include those obtained by synthesis of epichlorohydrin polyol or polyvalent phenol, glycerol polyglycidyl ether or polyglycerol polyglycidyl ether. , resorcinol diglycidyl ether, sorbitol polyglycidyl ether, ethylene glycol II A compound such as glycidyl ether is preferred. The amount of the surface treatment agent containing the epoxy compound adhered to the surface of the fiber is preferably from 0.05 to 1.5% by weight, preferably from 0.10 to 1.0% by weight. A smoothing agent, an emulsifier, an antistatic agent, or other additives may be mixed in the surface treatment agent as necessary.

This attachment of the present invention has an epoxy group having a rubber reinforcing agent, a surface treatment of polyester fibers with an epoxy-based index to the fiber surface 1.0 × 10 ^-3 eq / kg or less is preferable. Further, the epoxy index of the surface-treated polyester fiber per 1 kg is preferably 0.01 × 10 ^-3 to 0.5 × 10 ^-3 equivalent / kg. In the case where the epoxy index of the fiber surface is high, there is a tendency for a large amount of unreacted epoxy compound. For example, viscous scum in the filting step may be generated in a large amount in the yarn hook, and the step of the fiber is passed. When it is lowered, there is a problem that the quality of the product which causes unevenness of the crepe is lowered.

The polyester fiber for rubber reinforcement of the present invention has a surface treatment agent having an epoxy group as described above, and further preferably an epoxy curing catalyst adheres to the surface of the fiber. Here, the epoxy curing catalyst is a hardening agent which hardens an epoxy compound which is an essential component of the present invention. A suitable epoxy hardening catalyst is specifically an amine compound, and an aliphatic amine compound is preferred. More preferably, it is an amine compound obtained by adding 2 to 20 moles of ethylene oxide and/or propylene oxide to an aliphatic amine having 4 to 22 carbon atoms.

On the other hand, the surface of the rubber reinforcing polyester fiber of the present invention (the surface of the raw yarn) preferably has a terminal carboxyl group content of 10 equivalents/ton or less. In the polyester fiber for rubber reinforcement of the present invention, the amount of the carboxyl group of the entire polymer is 20 equivalents/ton or more as described above, and the amount of the carboxyl group on the surface of the fiber is determined by the reaction with the epoxy compound attached to the surface of the fiber. 10 equivalents below this value /ton below is better. As described above, the carboxyl group in the polymer reacts with the epoxy group on the surface of the fiber, and the polyester fiber for rubber reinforcement of the present invention can have extremely excellent adhesion properties. In this case, when the amount of terminal carboxyl groups on the surface of the fiber remains excessive, heat resistance or adhesion tends to decrease.

Further, in the polyester fiber for rubber reinforcement of the present invention, the amount of terminal methyl groups in the fibers is preferably 2 equivalents/ton or less. It is further preferred that the terminal methyl group is not contained. This is because the methyl group in the polyester polymer has low reactivity and does not react with the epoxy group. The terminal methyl group in this polyester polymer is produced from the dimethyl terephthalate in the raw material. Therefore, the polyester fiber for rubber reinforcement of the present invention is preferably composed of a polyester polymer produced by a direct polymerization method (direct esterification method) in which dimethyl terephthalate is not used. In the case where there is no terminal methyl group or a small amount in the polymer constituting the fiber, high reactivity with the epoxy group in the surface treatment agent can be ensured, and high adhesion or surface protection property can be ensured.

In the polyester fiber for rubber reinforcement of the present invention, the content of the titanium oxide in the fiber is preferably in the range of 0.05 to 3% by weight. Usually, the inclusion of titanium oxide in the high-strength polyester fiber causes the foreign matter to cause a decrease in the spinnability, so this situation is mostly avoided. However, in order to prevent a decrease in strength due to friction in the production step or a decrease in fatigue resistance of the polyester fiber in the rubber, and to maintain the strength of the final product, it is also considered that a small amount of such titanium oxide is contained in the polyester fiber. Suitable. When the content of the titanium oxide is less than 0.05% by weight, the smoothing effect of dispersing the stress generated between the roll and the fiber in the stretching step tends to be insufficient, and the strength of the finally obtained fiber is increased. There are disadvantages. Conversely, the content is higher than 3 In the case of amount %, the titanium oxide becomes a foreign matter in the polymer to hinder the elongation, and the strength of the finally obtained fiber tends to decrease.

The strength of the rubber reinforcing polyester fiber of the present invention is preferably in the range of 4.0 to 10.0 cN/dtex. Further, it is preferably 5.0 to 9.5 cN/dtex. In the case where the strength is too low, the durability is poor, and in the case where the strength is too high, the durability of the rubber tends to be deteriorated as a result. For example, when the production is carried out at a high strength, the yarn breaking tends to occur in the spinning step, and there is a tendency that the quality stability of the industrial fiber is problematic.

Further, the dry heat shrinkage ratio of the fiber at 180 ° C is preferably from 1 to 15%.

When the dry heat shrinkage rate is too high, the dimensional change during processing tends to become large, and the dimensional stability of the molded article using the fiber tends to be deteriorated.

Further, when the polyester fiber of the present invention is used in the form of a short fiber, the physical properties of the fiber before the cutting may be in the range as described above, for example, the value of the dry heat shrinkage ratio is 1 to 15%. The range is good.

The monofilament fineness of the polyester fiber of the present invention is not particularly limited, and is preferably from 0.1 to 100 dtex/monofilament from the viewpoint of the yarn-forming property. In particular, it is preferably from 1 to 20 dtex/monofilament from the viewpoint of strength, heat resistance or adhesion of the fiber for rubber reinforcement or the fiber for industrial materials such as a hose or a conveyor belt.

The total fineness is not particularly limited, and is preferably from 10 to 10,000 dtex, and particularly preferably as a rubber reinforcing fiber such as a hose or a conveyor belt or a fiber for industrial materials, preferably 250 to 6000 dtex. In addition, regarding the total fineness, For example, it is preferable to combine two filaments of 1000 dtex to have a total fineness of 2000 dtex, and to perform 2 to 10 filaments in the middle of spinning or stretching or after spinning and stretching.

The rubber reinforcing polyester fiber of the present invention can be obtained, for example, by the production method of another polyester fiber of the present invention.

The method for producing a polyester fiber of the present invention comprises melt-extruding a polyethylene terephthalate polymer having an intrinsic viscosity of 0.9 or more and a terminal carboxyl group content of 15 equivalents/ton or more, and adding an epoxy hardening catalyst. After the spinning oil is applied at a rate of 2000 to 6000 m/min, a finishing oil containing an epoxy compound is added after the stretching, and a manufacturing method of the ripening treatment is performed.

In the polyethylene terephthalate polymer used for melt extrusion in the present invention, the main repeating unit of the polyester is a polymer of ethylene terephthalate. Here, the content of the main recoating unit of the polyester is preferably 80 mol% or more, particularly 90 mol%, based on the total dicarboxylic acid component constituting the polyester. The above polyester is preferred. Further, when the content in the polyester polymer is small, a copolymer containing an appropriate third component may be used.

Further, the inherent viscosity of the polyester polymer must be 0.9 or more, and further preferably 0.93 to 1.10, particularly preferably 0.95 to 1.07. When the intrinsic viscosity is less than 0.9, the strength of the polyester fiber obtained by melt spinning is lowered, and it is difficult to obtain a high-strength polyester fiber.

Further, in the method for producing a polyester fiber of the present invention, the polymer has an intrinsic viscosity of 0.9 or more and a terminal carboxyl group of the polymer. The amount is up to 15 equivalents/ton or more. The upper limit is preferably 30 equivalents/ton or less, and further, the terminal carboxyl group amount in the polymer stage is in the range of 16 to 25 equivalents/ton, particularly preferably in the range of 18 to 23 equivalents/ton. It is considered that the amount of terminal carboxyl groups in the high-strength polyester fiber for rubber reinforcement is usually small. Therefore, in view of low productivity, a polymer having a large amount of terminal carboxyl groups is often used. However, in terms of durability in rubber fiber composites, fiber strength and rubber. The adhesion between the fibers is important, and the inventors of the present invention have focused on this, and in this way, the amount of terminal carboxyl groups is adjusted to a high range, and spinning at a high speed of 2000 to 6000 m/min is combined with other conditions, that is, High-speed spinning is combined with the most suitable epoxy treatment to achieve a more suitable polyester fiber for rubber reinforcement. Further, in the production method of the present invention, it is not necessary to intentionally reduce the amount of terminal carboxyl groups, so that the yield or productivity at the time of polymer polymerization is also improved, and the polymer can further reduce the production cost of the fiber.

Further, regarding the polymerization method of the melt-spun polyester polymer, a DMT method (transesterification method) made of dimethyl terephthalate and ethylene glycol and a terephthalic acid and an ethylene compound are known. A direct polymerization method (direct esterification method) for producing an alcohol, and any of the methods of the present invention can be used. However, in the polyethylene terephthalate produced by the DMT method, the terminal group has a methyl group derived from dimethyl terephthalate in addition to the carboxyl group which is necessarily used in the present invention. The end exists. In order not to react with the epoxy group in the finishing oil, the methyl terminal is preferably as small as possible. In the present invention, the polyester polymer is polymerized by a direct polymerization method in the absence of a terminal methyl group. Things are better. By using direct polymerization The ester polymer ensures a high level of reactivity of the carboxyl groups on the surface of the fiber with the epoxy group.

Further, the polyester polymer used in the present invention preferably has a titanium oxide content in the polymer of 0.05 to 3% by weight. When the content of the titanium oxide is less than 0.05% by weight, in the stretching step after the fiberization or the like, the smoothing effect of dispersing the stress generated between the roll and the fiber tends to be insufficient, and the fiber finally obtained is obtained. The high strength will have an unfavorable tendency. On the other hand, when the content is more than 3%, the titanium oxide becomes a foreign matter inside the polymer to hinder the elongation, and the strength of the finally obtained fiber tends to decrease. In general, in the production of high-strength polyester fibers, since titanium oxide is contained in the polymer, the foreign matter causes a decrease in the yarn-making property, and thus it is often avoided. However, in order to prevent a decrease in strength due to friction in the production step or to prevent a decrease in fatigue resistance of the polyester fiber in the rubber, it is preferred to contain a small amount of such titanium oxide in the polyester polymer.

Further, in order to set the intrinsic viscosity of the polyester polymer to 0.9 or more, the polyester polymer used in the present invention is preferably solid phase polymerization. In the production method of the present invention, the intrinsic viscosity at least in the polymer stage needs to be as high as 0.9 or more at the stage before melt spinning.

In the method for producing a polyester fiber of the present invention, it is necessary to extract the polyester polymer as described above at a high speed of from 2,000 to 6,000 m/min, and then carry out the stretching. In the case of high-speed extraction as described above, the fiber becomes a partial alignment yarn at the stage before the elongation, and then combined with the extension, thereby forming a polyester fiber having a high modulus and a low shrinkage ratio. Further, by performing high-speed spinning like this, the productivity can be improved.

The discharge amount of the polyester polymer sprayed from the metal spun nozzle is preferably in the range of 420 g/min to 1800 g/min, and more preferably 500 g/min to 1000 g/min, from the viewpoint of productivity. Further, when the polymer is ejected, the spinning stretching (the linear velocity/extraction speed at which the polymer is ejected from the metal spun nozzle) is preferably in the range of 500 to 4,000, more preferably in the range of 1,000 to 2,500. The alignment crystallization of the fibers can be promoted by using such a high spinning draw ratio.

As described above, in the production method of the present invention, it is necessary to spin at a high speed, and it is more preferable to use a heated spinneret having a molten polymer temperature or higher after being ejected from a metal spun nozzle. At this time, the length of the heating spinning drum is preferably 10 to 500 mm. After being ejected from the metal spout, the polymer tends to be immediately aligned and is prone to breakage, so it is preferable to use a heated spinneret to delay cooling in this manner. By heating the spinneret of the spinning cylinder, it is preferably cooled by blowing cold air of 30 ° C or less. Further, cold air of 25 ° C or less is preferred.

Further, the polyester fiber obtained by high-speed spinning as described above preferably has a long period of 12 nm or less as measured by X-ray small angle diffraction. In order to reduce the long period like this, it is preferable to make the melt spinning speed higher, and in the low speed spinning, the long period value becomes large. In addition, in the industry, the lower limit of the long period is preferably about 9 nm. Further, the long period system measured by X-ray small angle diffraction is preferably in the range of 10 nm to 11 nm.

The term "long period" as used herein refers to the interval between crystallization and crystallization in the polyester polymer in the direction of the longitudinal axis of the fiber (the direction in which the fibers are spun). Long week here In the case of a small period, it means that the interval between crystals in the polyester fiber is short. On the other hand, in the case where the long period is in this range, the number of the molecules which are directly linked to the crystal and the crystal is not interrupted, and the fiber in the rubber can be used in the case of using the fiber for rubber reinforcement. The strength maintenance rate is maintained at a high value. Therefore, even in the case of the production method of the present application in which the amount of terminal carboxyl groups in the polymer is spun more than the conventional conditions, sufficient durability can be obtained by surface treatment such as epoxy treatment. In addition, in the range of such a long period, the physical properties of the fiber are high modulus and low shrinkage, and the physical properties of the fiber for rubber reinforcement are obtained.

Further, the conditions for extending the fibers obtained by high-speed spinning are preferably 1.5 to 5.0 times after spinning. Such a high-strength extended fiber can be obtained by stretching at a high magnification like this.

The method for extending the polyester fiber in the present invention can be extended by being temporarily entangled after being extracted from the extraction roller, which is carried out by a so-called segment stretching method. However, it is preferable to continuously carry out the stretching step by the extraction roller to supply the unstretched wire. The so-called direct extension method is extended. In addition, the extension condition is preferably extended from 1 to more stages, and the elongation load ratio is preferably 60 to 95%. The extension load ratio is the ratio of the tension at the time of stretching to the tension of the fiber actually broken.

The preheating temperature at the time of stretching is preferably at least 20 ° C lower than the glass transition point of the polyester undrawn yarn, and preferably lower than the crystallization start temperature by 20 ° C or lower. The stretching ratio is determined in accordance with the spinning speed, and is preferably extended at a stretching ratio in which the elongation load ratio is 60 to 95% with respect to the breaking stretch ratio. In addition, in order to maintain fiber strength and improve dimensional stability, the temperature is increased from 170 ° C to the melting point of the fiber in the stretching step. Heat fixation is preferred. Further, it is preferable that the heat setting temperature at the time of stretching is 170 to 270 °C.

Further, the method for producing the polyester fiber of the present invention is premised on the use of the pretreated polyester fiber. The prior treatment method is to add a spinning oil agent containing an epoxy hardening catalyst after melt extrusion of the polymer, and then High-speed extraction, followed by extension, and then adding a finishing oil containing an epoxy compound for heat treatment.

The epoxy curing catalyst contained in the spinning oil agent after melt spinning may be an epoxy curing agent which can cure the epoxy compound contained in the finishing oil agent, and an alkaline curing catalyst is preferable. In particular, an amine compound is preferred. More specifically, for example, an aliphatic amine compound or the like, more preferably an amine compound having an alkylamine having 4 to 22 carbon atoms and 2 or 20 moles of propylene oxide is the most Suitable for.

In the production method of the present invention, the spinning oil agent may contain, in addition to the above epoxy curing catalyst, a usual polyester fiber spinning agent such as a smoothing agent, an emulsifier or an antistatic agent. The substance is used as a constituent of other spinning oils. However, it is preferred that the spinning oil is free of an epoxy compound. Specific examples of other specific components include smoothing agents such as mineral oils and fatty acid esters; emulsifiers such as higher alcohols or ethylene oxide (EO) adducts; and antistatic agents such as anionic surfactants, cationic surfactants, and the like. .

The ratio of each component in the spinning oil is 3 to 20% by weight of an epoxy curing catalyst (amine compound, etc.), 30 to 80% by weight of a smoothing agent, 20 to 70% by weight of an emulsifier, and other additives. Become a combination of 100% by weight It is better. By setting this formulation, the adhesion or durability of the obtained pretreated filament can be improved, and the original smoothness and bundling function of the spinning oil can be exerted, and the guide in the spinning step can be reduced. Contamination of yarn hooks or extension rollers.

The rubber reinforcing fiber of the present invention can be obtained by a method for producing a polyester fiber of the present invention as described above or the like. Further, in order to use for rubber reinforcement, it is also suitable to use the polyester fiber for rubber reinforcement of the present invention as a multifilament yarn and to form a rope by applying a twisted yarn. This rubber reinforcing polyester fiber rope is obtained by twisting the multifilament fiber, and the strength utilization rate is averaged, and the fatigue resistance in the rubber is improved. The number of turns is preferably in the range of 50 to 1000 times/m, and the string of the lower jaw and the upper jaw is also suitable. The coefficient of 捻 is K=T. D ^1/2 (T is the number of turns per 10 cm, and D is the fineness of the string) is preferably 990 to 2500.

Further, the number of filaments constituting the yarn before the yarn joining is preferably from 50 to 3,000. By making such a multifilament, fatigue resistance or softness is further enhanced. In the case where the fineness is too small, there is a tendency that the strength is insufficient. On the other hand, when the fineness is too large, there is a problem that it becomes too thick to be flexible, or it is likely to cause sticking between the filaments at the time of spinning, and it is difficult to stably manufacture the fibers.

In addition, the polyester fiber for rubber reinforcement of the present invention is to add fibers to the surface thereof. RFL (resorcinol. Formalin. Latex) adhesive for rubber is preferred. The rubber-reinforcing polyester fiber of the present invention which has been subjected to the subsequent treatment is embedded in an unsulfurized rubber and vulcanized, whereby a fiber-rubber composite can be obtained, and a conveyor belt or a hose which is a rubber material is most preferably used.

The rubber reinforcing polyester fiber of the present invention can maintain physical properties of high modulus and low shrinkage, and the carboxyl terminal in the polymer reacts with the epoxy group in the surface treating agent to have high adhesion. In addition, a fiber having a high intrinsic viscosity, a small long period in the fiber axis direction, and excellent durability can be used as a durability end in rubber by the effect of multiplying the epoxy group on the surface of the fiber with the surface protection effect at the carboxyl end. Excellent fiber. Therefore, in particular, the polyester fiber for rubber reinforcement of the present invention can maintain the adhesiveness or fatigue resistance of the rubber at a high level even after bending fatigue in the rubber, and becomes a susceptibility pole after high-temperature dynamic fatigue. Excellent polyester fiber for rubber reinforcement. In particular, a fiber-rubber composite which is subjected to movement such as bending or high-speed rotation, such as a V-belt, can ensure high fatigue resistance even in a state of high-load dynamic deformation, and at the same time, it is a high modulus. Since it has a low shrinkage rate, it is also a maintenance-free property, and it can satisfy various characteristics at a high level.

Further, the polyester fiber for rubber reinforcement of the present invention is suitably used as a fiber-reinforcing composite in various forms such as rope, woven fabric, and short fiber.

For example, in the case of a form of a fiber rope which is twisted, it is possible to use a rope for reinforcing a hose or a belt for reinforcing a belt.

When the polyester fiber of the present invention is used as a hose reinforcing cord, physical properties of a high modulus and a low shrinkage ratio can be maintained while having high adhesion. In addition, since the fiber having a long period of time and excellent durability has an effect of multiplying the epoxy group on the surface of the fiber with the surface of the carboxyl group to produce a surface protection effect, it is a fiber rope excellent in durability in the hose base. In addition, use this hair When the fiber rope for reinforcing the hose of the polyester fiber is bent and fatigued in the hose base, the adhesion to the substrate or the fatigue resistance can be maintained at a high level, and the adhesion after high-temperature dynamic fatigue is extremely excellent. Hose reinforcement fiber rope. This type of hose reinforcement fiber rope is most suitable for use in a variety of hoses, especially rubber hoses.

The hose is preferably a fiber-reinforced hose composed of the above-mentioned polyester fiber of the present invention and a fiber-reinforced hose composed of rubber or resin.

Such a hose, if it is, for example, a rubber hose, can be manufactured as follows. First, the obtained fiber rope is placed on the inner layer made of tubular rubber at a predetermined angle by a braider to have a predetermined density. Next, after the interlayer rubber sheet is placed thereon, the fiber rope is again disposed by the knitting machine, and this step is performed a predetermined number of times. Finally, an outer layer is formed by covering rubber for protecting the outer reinforcing fibers, and then steam vulcanized in, for example, a steam vulcanization kettle to form a rubber hose. Further, the arrangement of the above-mentioned fiber ropes is preferably set to a spiral structure.

In recent years, the use of fiber-reinforced hoses has become more stringent. For example, the engine room of a car has become more compact, and in order to improve energy efficiency, it has gradually developed toward the high temperature in the engine room. In this case, particularly in the use of piping for piping, etc., the size of the hose does not change, and in the state of high temperature or tension, the reinforcing fiber rope must have a high level of dimensional stability. Further, particularly in the case where the hose is used in the movable portion, in addition to the internal pressure variation of the gas or liquid in the hose, external physical factors may require durability even when the shape of the hose is changed.

The polyester fiber of the application of the invention has low shrinkage and excellent dimensional stability At the same time, it has excellent adhesion to rubber and improves fatigue resistance. The hose using the polyester fiber of the present invention can satisfy the above requirements at a high level.

Further, the polyester fiber for rubber reinforcement of the present invention is also suitably used as a fiber material for reinforcing a conveyor belt. The belt reinforcing fiber material is preferably a belt reinforcing fiber material obtained by forming the obtained polyester fiber into a multifilament and using a twisted yarn to form a rope. Further, a fiber material for a belt reinforcement used in the form of a woven fabric of the obtained polyester fiber is also suitable.

For example, in the case where the reinforcing fiber material for the belt is a woven fabric, the warp yarn constituting the woven fabric is preferably a yarn composed of the polyester fiber of the present invention. The yarn is preferably in the form of the above-mentioned fiber rope.

More specifically, when it is used as a material for a belt-shaped belt reinforcement, the polyester fiber of the present invention as described above is subjected to a twisted yarn, and 1000 to 1500 are arranged as warp yarns, and these warp yarns are used. It is preferable that the non-twisted yarn of the synthetic fiber such as polyamide fiber or polyvinyl alcohol fiber or the twisted yarn having a twist coefficient of 5,000 or less is used as the weft, and the woven fabric is simultaneously woven to form a fiber material for reinforcing the belt.

The fabric structure of this fabric is not particularly limited. However, the twill weave or the satin weave is increased in strength at a certain elongation, and when a base fabric as a conveyor belt is used, a high tension can be generated with a small amount of stretching, so that noise generation can be reduced when the conveyor belt is operated. Therefore, it is particularly suitable, and is suitable for use in a conveyor belt such as a conveyor belt for a conveyor.

These woven fabrics are preferably the same as the above-mentioned fiber ropes in that an adhesive is added to the surface thereof. For example, in rubber reinforcement applications, RFL is used to process The agent is processed to be most suitable. The conveyor belt can be formed by embedding the subsequently-treated belt material reinforcing fiber material of the present invention in an unsulfurized rubber and vulcanizing it.

The polyester fiber of the present invention can maintain physical properties of high modulus and low shrinkage while having high adhesion. Further, the fiber excellent in durability is extremely excellent in adhesion durability in the matrix. Therefore, the fiber material for reinforcing the belt containing the polyester fiber of the present invention can maintain the adhesion or fatigue resistance of the substrate at a high level even after bending fatigue in the matrix, and after high temperature dynamic fatigue A fiber material for belt reinforcement for excellent adhesion. In particular, V-shaped conveyor belts and other fibers that are often bent or rotated at high speed. The matrix composite ensures high fatigue resistance even in the state of high dynamic deformation, and is due to high modulus. Since it has a low shrinkage rate, it is also a maintenance-free property, and it can satisfy various characteristics at a high level.

Such a belt reinforcing fiber material using the polyester fiber of the present invention is particularly suitably used for a core of a power transmission belt which is a V-shaped belt or the like. 1 and 2 illustrate a representative use case thereof. Fig. 1 is a longitudinal sectional view showing the obtained V-shaped belt 1. The V-shaped conveyor belt may be a type of conveyor belt in which the rubber-coated cloth 2 woven from natural fibers or synthetic fibers is present only on the upper surface or the lower surface of the conveyor belt. The core wire 3 composed of the polyester fiber of the present invention is embedded in the adhesive rubber layer 4 which is in contact with the compression rubber layer 5. In the compression rubber layer 5, short fibers 6 are mixed in the width direction of the conveyor belt.

Further, the use of the fiber rope using the polyester fiber of the present invention is not affected. As defined in the V-shaped conveyor belt of the type shown in Fig. 1, it is also possible to use a core of a V-shaped conveyor belt of the entire circumference of the conveyor belt as a rubber-coated cloth 2, and it is also possible to use it as a bit. As shown in Fig. 2, the above-mentioned compression rubber layer 5 has a core wire of a rib-type V-shaped conveyor belt 8 having a plurality of ribs 7 in the longitudinal direction of the conveyor belt.

In addition, the fiber material for reinforcing the conveyor belt may be a woven fabric. In this case, for example, by twisting the polyester fiber, 1000 to 1500 are arranged as warp yarns, and the warp yarns are blended with polyamine. A non-twisted yarn of a synthetic fiber such as a fiber, a polyester fiber, or a polyvinyl alcohol fiber, or a twisted yarn having a twist coefficient of 5,000 or less is used as a weft yarn, and a woven fabric is simultaneously produced to obtain a desired fiber material for reinforcing a belt. Reinforce the base fabric. The woven fabric is preferably twill or satin weave. By making a twill weave or a satin weave, the strength is increased at a certain elongation, and when a base fabric as a conveyor belt is used, a high tension can be generated with a small amount of stretching, and the noise during operation of the conveyor belt can be reduced. The production. It is particularly suitable for use in conveyor belts such as conveyor belts for conveyors.

The fiber material for reinforcing the belt using the polyester fiber of the present invention obtained in this manner is used together with a polymer such as rubber or resin to form a fiber. Conveyor belt for polymer composites. In this case, the polymer is preferably a rubber elastomer. Since the polyester fiber used for reinforcement is excellent in heat resistance and dimensional stability, the composite is excellent in moldability when it is made into a composite. It is particularly suitable for use as a rubber conveyor belt reinforcement, and can be suitably used for, for example, a V-belt or a conveyor belt for a conveyor.

Further, the polyester fiber for reinforcing rubber of the present invention may also be suitable Used in short fibers for rubber reinforcement.

Conventionally, in the field of short-fiber-reinforcing composites, particularly in applications where fatigue resistance is emphasized, when a heavy load is applied, there is a problem that the adhesion of the added short fibers is low. In particular, in terms of fatigue resistance in a high temperature state, the adhesion between the fiber and the rubber is lowered, and the detached portion is a disadvantage of the molded article. If it is subjected to a load, it is likely to be cracked in this portion, resulting in a decrease in fatigue characteristics. Especially in terms of the improvement of the bending fatigue resistance, there is still a problem of insufficient performance.

The short fiber for rubber reinforcement which is composed of the polyester fiber of the present invention can solve such a problem, and is a short fiber for rubber reinforcement which is excellent in the reinforcing effect and the bending fatigue resistance.

The fiber length of the short fiber for rubber reinforcement using the polyester fiber of the present invention is preferably from 0.3 to 10.0 mm. When it is less than 0.3 mm, it is difficult to obtain the reinforcing effect by the short fibers, and when it is longer than 10.0 mm, the short fibers are likely to be entangled with each other, and there is a tendency that the fibers are not uniformly dispersed in the rubber.

Further, the monofilament fineness of the polyester staple fiber is preferably from 0.1 to 100 dtex/root. Further, from the viewpoint of strength, heat resistance or adhesion, it is preferably from 1 to 20 dtex/root.

Such a polyester reinforcing polyester staple fiber can be obtained by cutting a polyester fiber of the present invention obtained by spinning and stretching as described above into a predetermined length.

The polyester reinforcing short fiber has a surface treating agent having an epoxy group attached to the surface of the fiber, and the manufacturing method is from the viewpoint of operability. It is preferred to use a surface treatment in the long fiber stage and then cut off. The surface treating agent having an epoxy group herein contains the above epoxy compound.

Further, the polyester reinforcing polyester staple fiber is added to the surface of the fiber. RFL (resorcinol. Formalin. Latex) adhesive for rubber is preferred. Cutting the long fibers into short fibers can be performed before and after the addition of the RFL adhesive, and from the viewpoint of operability, it is preferable to perform the cutting after the addition of the RFL adhesive. The rubber reinforcing polyester staple fiber of the present invention which has been subjected to the subsequent treatment is kneaded to an unvulcanized rubber, and short fibers are embedded in the rubber, followed by vulcanization, thereby making a suitable fiber. Rubber compound.

The polyester reinforcing polyester staple fiber composed of the polyester fiber of the present invention can maintain a high modulus of low modulus and a low shrinkage property suitable for matrix reinforcement, and has high adhesion. In addition, it is a fiber excellent in durability and a short fiber excellent in adhesion durability in rubber.

In particular, the polyester short fiber for rubber reinforcement can maintain the adhesiveness or fatigue resistance of the rubber at a high level even after bending fatigue in the rubber, and the adhesive pole after dynamic fatigue at high temperature. Excellent polyester staple fiber for rubber reinforcement. Especially as a fiber that often bends or rotates at high speed. The rubber composite ensures high fatigue resistance even in the state of high dynamic deformation, and is high modulus. Since it has a low shrinkage rate, it is also a maintenance-free property, and it can satisfy various characteristics at a high level.

The polyester reinforcing polyester staple fiber obtained in this manner can be used together with a rubber to form a molded body excellent in strength and durability. For example, it will not The vulcanized rubber and the short fiber for rubber reinforcement are kneaded by a kneader or the like to be dispersed, and then a short fiber-reinforced rubber molded article can be obtained by vulcanization. Since the obtained molded article is excellent in strength and fatigue resistance, it is most suitably used as various rubber products such as a conveyor belt, a hose, and a tire.

[Examples]

The invention is further illustrated in the following examples, which are not to be construed as limited. In addition, various characteristics were measured by the following methods.

(1) Intrinsic viscosity:

A thin solution obtained by dissolving polyester chips and polyester fibers in o-chlorophenol at 100 ° C for 60 minutes was measured at 35 ° C using an Ubbelohde viscometer and determined from the measured values. The table is IV.

(2) The amount of terminal carboxyl groups

A powder sample of 40.00 g of a polyester sample and a benzyl alcohol 100 ml were added to the flask using a pulverizer, and the polyester sample was dissolved in benzyl alcohol under a nitrogen stream at 215 ± 1 ° C for 4 minutes. After the solution is dissolved, the sample solution is cooled to room temperature, and an appropriate amount of a phenol red benzyl alcohol 0.1% by mass solution is added thereto, and the benzyl alcohol solution of sodium hydroxide is used to rapidly titrate the amount of the dying. Set to Aml. Adding the same amount of phenol red benzyl alcohol 0.1% by mass solution to 100 ml of benzyl alcohol as a blank sample, and rapidly titrating with a benzyl alcohol solution of N-specified sodium to cause discoloration to occur as The amount of drip was determined to be Bml. From these values, the terminal COOH group content (end carboxyl group amount) in the polyester sample was calculated by the following formula.

Terminal COOH group content (equivalent/ton) = (AB) × 10 ³ × N × 10 ⁶ / 40

Further, the benzyl alcohol used herein is a benzyl alcohol which is distilled in a light-shielding bottle by using an article which is a reagent grade. A benzyl alcohol solution of sodium hydroxide having an equivalent concentration of N is titrated with a sulfuric acid solution having a known concentration in advance by a predetermined method to accurately obtain a solution having an equivalent concentration N.

(3) The amount of surface carboxyl groups (the amount of carboxyl groups at the end of the fiber surface)

The amount of carboxyl groups (acid value) on the surface of the fiber was determined according to the JIS K0070-3.1 neutralization titration method. That is, 50 ml of a diethyl ether/ethanol = 1/1 solution was added to about 5 g of the fiber sample, and a few drops of the phenolphthalein solution as an indicator were added, and ultrasonic vibration was performed for 15 minutes at room temperature. The solution was titrated with 0.1 ml of potassium hydroxide ethanol solution (coefficient value f = 1.030), and the light red color of the indicator was determined as the end point for 30 seconds, and the amount of the indicator was measured. The acid value was calculated from the following formula. .

Acid value A (equivalent/ton) = (B × 1.030 × 100) / S [here, B represents 0.1 ml of a potassium hydroxide ethanol solution titration (ml), and S represents a sample amount (g)].

(4) terminal methyl group

After the polyester was hydrolyzed and separated into an acid component and a glycol component, the methyl ester component of the acid was quantified by gas chromatography, and the value was calculated from this value.

(5) Titanium oxide content

The content of each element was measured by a fluorescent X-ray apparatus (Rigaku Corporation, Model 3270E) for quantitative analysis. In the case of this X-ray measurement, the polyester fiber resin polymer sample was heated at 260 ° C for 2 minutes in a calender, and a test molded body having a flat surface was produced under a pressure of 7 MPa and measured.

(6) Crystal grain size in the transverse direction of the fiber (X-ray diffraction)

About polyester composition. The X-ray diffraction measurement of the fiber was carried out using an X-ray diffraction apparatus (RINT-TTR3, Cu-Kα ray, tube voltage = 50 kV, current 300 mA, parallel beam method, manufactured by Rigaku Co., Ltd.). The long-period interval is obtained by irradiating a direction perpendicular to the fiber axis by a conventionally known method, that is, a Cu-K α ray having a wavelength of 1.54 Å as a radiation source by using a conventionally known method. The ray of the meridian interference is calculated using the Bragg formula (unit; nm ² ). The crystal grain size in the transverse direction of the fiber was obtained by X-ray wide-angle diffraction to obtain an (010) (100) intensity distribution curve of the equatorial line scan, which was obtained from the half width in the distribution curve using the Scherrer formula.

(7) Epoxy index (EI)

The polyester fiber after the heat treatment was measured for the epoxy index (EL: the number of epoxy equivalents per 1 kg of the fiber) in accordance with JIS K-7236.

(8) Strong tensile ratio (%) of fiber and intermediate stretching ratio (%)

A tensile load measuring instrument (Autograph manufactured by Shimadzu Corporation) was used for measurement in accordance with JIS-L1013. Further, the intermediate stretch ratio indicates the elongation at a strength of 4 cN/dtex.

(9) Dry heat shrinkage rate (%)

According to JIS-L1013, after being placed in a room controlled by temperature and humidity of 20 ° C and 65% RH for 24 hours, heat treatment at 180 ° C × 30 min in a dryer under no load condition, and the difference in length of the sample before and after heat treatment Calculation.

(10) Step evaluation

Regarding the evaluation of the steps of treating the polyester fiber before the present invention, it is considered from the aspects of production stability, silk scum, production efficiency, economy, +++: excellent; ++: ordinary; +: bad 3 stage To evaluate polymer costs.

(11) Heat resistance strength retention rate

Two polyester fibers were placed on the upper 捻470 times/m and the lower jaw was 470 times/m to prepare a raw rope. The raw rope was immersed in an RFL adhesive, and treated under tension at 240 ° C for 2 minutes to obtain a treated rope. , measuring the strength of the treated rope , the measured value is determined as the intensity A. Then, the treatment rope is embedded in a vulcanization mold, and sulfur is added at 80 ° C for 120 minutes, and the treated rope after the promotion of the sulfurization is taken out and the strength is measured, and the measured value is determined as the strength B by B/A ( The formula of %) finds the strength maintenance rate.

(12) Initial peeling force

This value represents the adhesion of the treated rope to the rubber. The rope was pulled neatly at 36 pieces/2.54 cm (inch), and the non-sulfurized rubber sheet with the support added with 0.5 mm thick natural rubber as a main component was sandwiched. These sheets were superposed in the straight direction, and vulcanized at a temperature of 150 ° C at a rolling pressure of 50 kg/cm ² for 30 minutes, and then cut into strips along the rope direction. The long piece of the sample to be produced was peeled off at a speed of 200 mm/min in a direction of 90 degrees with respect to the surface of the rubber sheet, and the force required for the peeling was expressed by N/2.54 cm (inch). . Further, the initial peeling adhesion force is a value obtained by measuring at room temperature.

(13) Evaluation of the subsequent performance of rubber after dynamic fatigue (shoe-shoe measurement (1))

The 2.5 mm thick SBR/NR-based rubber was sandwiched, and the obtained rope was made into a two-layer single-layer layer which was arranged in parallel with each other at a density of 26 pieces/2.54 cm (inch), and the outer side of each single-layer layer was further After covering with a 1.5 mm thick SBR/NR-based rubber, vulcanization was carried out under the conditions of a temperature of 150 ° C, 30 minutes, and 90 kg/cm ² to prepare a conveyor belt having a length of 500 mm, a width of 5 mm, and a thickness of 5.5 mm.

Next, a load of 50 kg / 2.54 cm (inch) is applied to the conveyor belt. And installed on a 50mm diameter pulley, at a temperature of 100 ° C, it takes 5 hours to carry out 30,000 cycles of repeated tensile compression fatigue. The single cloth layer of the conveyor belt after stretching and compressing fatigue was peeled off at a speed of 300 mm/min, and the obtained average peeling adhesion force (N/2.54 cm (inch)) was obtained as an adhesive force after high-temperature dynamic fatigue.

This evaluation method is called dynamic bending test, the so-called shoe-shoe test evaluation method.

(14) Hose fatigue

Pressure was applied so that the pressure in the hose became 3.5 kg/cm ² , and the rotation was performed at 850 rpm in a state of being bent at 85°, the rotation direction was changed every 29 minutes, and the time (minutes) until the hose was broken was measured.

(15) Conveyor belt tension maintenance rate

A V-shaped conveyor belt was placed between the two pulleys with a diameter of 100 mm, the initial installation tension was set to 900 N, and the running pulley speed was set to 3600 r.p.m., and the operation test was performed at room temperature. Then, after running for 4 hours, the pressure was stopped, and the belt tension after cooling for 24 hours was further measured, and the tension maintenance ratio (%) with respect to the tension of the initial mounting was measured.

(16) Conveyor belt dimensional change rate

The difference in the dimensional change (%) of the conveyor belt was calculated by dividing the difference between the outer circumference of the conveyor belt after vulcanization and the outer circumference of the V-belt after 30 days by the outer circumference of the conveyor belt after vulcanization.

(17) Shoeshine test (2) (Evaluation of the subsequent performance of rubber after dynamic fatigue of the conveyor belt)

A load of 50 kg/2.54 cm (inch) is applied to a V-shaped conveyor belt and a base fabric reinforcing conveyor belt in which a polyester fiber is made into a core wire, and is mounted on a pulley having a diameter of 50 mm, and it takes 5 hours at a temperature of 100 ° C to carry out 30,000 cycles. Repeated compression and fatigue. The single cloth layer of the conveyor belt after stretching and compression fatigue was peeled off at a speed of 300 mm/min, and the obtained average peeling adhesion force (N/2.54 cm (inch)) was determined as the adhesion force after high-temperature dynamic fatigue.

(18) Degraded tensile strength and fracture elongation of short fiber reinforced rubber molded articles

This value indicates the reinforcing effect and elongation of the rubber molded article reinforced with short fibers. According to JIS K6301, the drop point load when the No. 3 dumbbell-shaped test piece is broken at a tensile speed of 500 mm/min is divided by the sectional area of the test piece. The obtained value was defined as the tensile strength at break (kg/cm ² ), and the elongation between the lines at the time of the fracture was defined as the elongation at break (%).

(20) Bending fatigue life of short fiber reinforced rubber molded articles

The DeMattia-type bending fatigue tester of Toyo Seiki Co., Ltd. was used to determine the fatigue resistance of the rubber-formed product reinforced with short fibers, and the dumbbell-shaped test piece No. 3 was bent at a cycle of 5 Hz in a gas atmosphere of 80 °C. 25%, the number of occurrences of cracks is defined as the bending fatigue life (10,000 times).

[Example 1] (a) Modulation of spinning oil

65 parts of triolein, 12 parts of POE (10) lauryl amine ether, 8 parts of hardened castor oil ether of POE (20), 12 parts of hardened castor oil trioleate of POE (20), POE (8) The oil composition consisting of oleyl phosphate Na2 part and 1 part of antioxidant was heated to 50 ° C in 10 parts.

(b) Modulation of finished oil

60 parts of polyglycerol polyglycidyl ether ("DENAKOL EX-512" manufactured by Nagase Chem Tex Co., Ltd.), 30 parts of diisooctyl sebacate, 8 parts of hardened castor oil ether of POE (8), and diisophoric sulfosuccinate After 45 parts of the oil component composed of the octyl ester Na2 part was heated to 40 ° C, it was slowly added to 55 parts of demineralized water heated to 40 ° C, and after stirring, it was cooled to 18 ° C.

(c) Manufacture of polyester fibers

The intrinsic viscosity of the chips after solid phase polymerization (measured by o-chlorophenol solvent at 35 ° C) was 1.03, the amount of terminal carboxyl groups was 20 equivalents/ton, the amount of terminal methyl groups was 0 equivalents/ton, and the content of titanium oxide was 0.05 wt%. The polyethylene terephthalate chips obtained by the direct polymerization method were obtained by a melt spinning method to obtain 384 monofilament polyester fibers under the conditions of a spinning stretch of 1777.

The spinning oil prepared by the above method was added to the undrawn yarn which was spun from a metal spout and extracted at 2800 m/min, so that it became 0.4 parts of the oil adhering component with respect to 100 parts of the fiber (aliphatic After the amount of the amine compound component adhered was 0.048% by weight, the first roll was taken at 60 ° C, and the first roll was extended to 1.25 times between the first roll and the second roll at 60 ° C, and further in the second stage. The second stage is extended between the roll and the third roll of 180 ° C to a total stretch ratio of 1.43 times, and then extended by a stretch ratio of 1.0 times between the third roll and the fourth roll. In the roller type oil additive method, the finished oil agent prepared by the above method is added so as to be 0.2 parts by weight (the epoxy compound component adhesion amount is 0.12% by weight) based on 100 parts of the fiber. Between the 4 rolls and the winding machine, after the entanglement was given by the interlacing (IL) nozzle, each 10 kg was wound at a speed of 5000 m/min. The obtained fiber system had mechanical properties of an intrinsic viscosity of 0.91, a fineness of 1,130 dtex, a strength of 6.9 cN/dtex, and a tensile ratio of 12%. The terminal carboxyl group amount was 22 equivalent/ton, the long period was 10 nm, and the fiber surface terminal carboxyl group. The amount is 7 equivalents/ton, the crystal grain size in the transverse direction of the fiber is 45 nm ² , the terminal methyl group amount is 0 equivalent/ton, the titanium oxide content is 0.05 wt%, and the surface epoxy group amount is 0.1 × 10 ^-3 equivalent / Kg.

The fiber obtained in this manner was subjected to a ripening treatment at a temperature of 30 ° C for 360 hours. Despite the high spinning speed, the amount of scum generated in the production step is small.

After the obtained polyester fiber was subjected to squatting at 470 times/m, two of them were combined, and a 470 times/m upper sputum was applied to obtain a rope, and resorcinol was used for the rope. Fomalin. The latex binder (RFL solution) was subjected to subsequent treatment, and heat treatment was carried out at 240 ° C for 2 minutes to prepare a treated rope.

The physical properties of the obtained polyester fiber and rope were 134 N, the elongation was 13%, the elongation at 44 N was 3.9%, and the dry heat shrinkage at 177 ° C was 2.7%.

As a result of performing the shoe-shoe measurement using this rope, the peeling force of the rope after dynamic fatigue was 550 N/inch, while maintaining a very high adhesion force. The physical properties of the obtained polyester fiber and treated rope and the results of subsequent evaluation are disclosed in Tables 1 and 2.

[Comparative Example 1]

The same procedure as in Example 1 was carried out except that the terminal carboxyl group of the fragment obtained by solid phase polymerization of Example 1 was changed from 20 equivalents/ton to 9 equivalents/ton, and polyester chips having a terminal methyl group amount of 5 equivalents/ton were used. The method was carried out, and the final fineness was the same 1130 dtex polyester fiber having an intrinsic viscosity of 0.91, which was twisted to obtain a treated rope. The physical properties of the obtained polyester fiber and treated cord, and the results of subsequent evaluation are shown in Tables 1 and 2. Compared with Example 1, the amount of terminal carboxyl groups of the fibers was 18 equivalents/ton, and was lower, and a usual peeling adhesion force was obtained, and the heat-resistant strength maintaining ratio was also sufficient. However, it is unfavorable in the adhesion (shoe-shoe measurement) after dynamic fatigue.

[Comparative Example 2]

In the same manner as in Comparative Example 1, except that the epoxy compound was not used and the non-amine-based spinning oil agent in which the amine component was removed by the spinning oil agent was used. The physical properties of the obtained polyester fiber and treated cord are shown in Tables 1 and 2 together with the results of subsequent evaluation. Compared with Comparative Example 1, it was poor even in the adhesion (shoe-shoe measurement) after dynamic fatigue.

[Embodiment 2]

The same procedure as in Example 1 was carried out except that the aging treatment at 30 ° C and 360 hours of Example 1 was changed to 60 ° C and heat treatment was carried out for 80 hours. Since the heat treatment is performed without performing the aging treatment, the amount of scum generated in the production step is large. The physical properties of the obtained polyester fiber and treated cord, and the results of subsequent evaluation are shown in Tables 1 and 2.

[Example 3]

The spinning speed of Example 1 was set to 2800 m/min to 3200 m/min, and in order to adjust the physical properties, the number of filaments was changed from 384 to 500, and the stretching ratio was adjusted, and the same procedure as in Example 1 was carried out. A polyester fiber having a final fineness of 1130 dtex and an intrinsic viscosity of 0.91 and a treated cord obtained by twisting it were obtained. The physical properties of the obtained polyester fiber and treated rope, and the results of the evaluation are shown in Tables 3 and 4.

[Example 4]

The spinning speed of Example 1 was set to 2,500 m/min, and in order to adjust the physical properties, the number of filaments was set to 384 to 249, and the stretching ratio was adjusted, and the final fineness was obtained in the same manner as in Example 1. The same polyester fiber of 1130 dtex and intrinsic viscosity of 0.91, and a treated rope obtained by twisting it. The physical properties of the obtained polyester fiber and the treated rope and the results of the evaluation are collectively shown in Tables 3 and 4.

[Comparative Example 3]

In the same manner as in Example 1, except that the epoxy compound was not used and the non-amine-based spinning oil agent which removed the amine component by the spinning oil agent was used. The physical properties of the obtained polyester fiber and treated rope and the results of subsequent evaluation are shown in Tables 3 and 4. Not only is it poor in the adhesion after the dynamic fatigue (shoe-shoe measurement), but the heat-resistant strength retention rate in the rubber is also lowered.

[Comparative Example 4]

A polyethylene terephthalate chip having an intrinsic viscosity (measured by an o-chlorophenol solvent at 35 ° C) of 1.03, a terminal carboxyl group of 20 equivalents/ton, and a terminal methyl group of 0 equivalent/ton was used for spinning and drawing. The condition of 60 was obtained by melt spinning to obtain 250 monofilament polyester fibers.

Adding the above-mentioned method to the unstretched yarn spun from a metal spout and extracting at 600 m/min, by using the prepared spinning oil agent, it becomes 0.4 parts of the oil adhering component with respect to 100 parts of the fiber (aliphatic After the amount of the amine compound component adhered to 0.048% by weight, the first roll was taken at 100 ° C. The first stage is extended to 3.0 times between the first roll and the second roll of 120 ° C, and the second stage is extended to the total between the second roll and the third roll of 190 ° C. The stretching ratio is 5.0 times. Then, after extending the stretching ratio of 0.97 times between the third roller and the fourth roller, the finishing oil prepared by the above method is added by a roller type oil addition method. The amount of the oil-binding component is 0.2 parts by weight (0.12% by weight of the epoxy compound component) with respect to 100 parts of the fiber, and the entanglement is imparted by the collateral (IL) nozzle between the fourth roller and the winding machine. Thereafter, each 10 kg was wound at a speed of 3400 m/min. Further, the conditions other than the above are the same as in the first embodiment. Low-speed spinning, the amount of scum generated is in a low level state.

The obtained fiber system had a mechanical property of a fineness of 1,130 dtex, an intrinsic viscosity of 0.91, a strength of 7.6 cN/dtex, and a tensile ratio of 14%, a terminal carboxyl group amount of 22 equivalent/ton, a long period of 14 nm, and a fiber surface terminal carboxyl group. The amount is 7 equivalents/ton, the crystal grain size in the transverse direction of the fiber is 35 nm ² , the terminal methyl group amount is 0 equivalent/ton, the titanium oxide content is 0.05 wt%, and the surface epoxy group amount is 0.1 × 10 ^-3 equivalent / Kg. The physical properties of the obtained polyester fiber and treated rope are shown in Tables 3 and 4 together with the results of subsequent evaluation.

Compared with Example 3, the long period of this Comparative Example 4 was as high as 14 nm, and no difference was observed in the tensile strength. However, the dry heat shrinkage ratio or the intermediate load stretch ratio was also large, and only the initial adhesion force was equal. However, it is clearly poor in the heat-resistant synergy retention rate in the rubber or the adhesion after the dynamic fatigue (shoe-shoe measurement).

[Example 5]

After the polyester fiber obtained in Example 1 was subjected to squatting at 470 times/m, two of the polyester fibers were combined and subjected to a 470 times/m upper sputum to obtain a rope, and resorcinol-formalin was used for the rope. The latex binder (RFL solution) was subjected to subsequent treatment, and subjected to shrink heat treatment at 240 ° C for 2 minutes to prepare a treated rope.

The cord composed of the obtained polyester fiber was molded into a hose using unvulcanized rubber, and then vulcanized by steam at 153 ° C for 35 minutes to obtain a rubber hose. Revealing the results of the fatigue evaluation of the obtained rubber hose table 5.

[Comparative Example 5]

A rubber hose was prepared in the same manner as in Example 4 except that the fiber of Comparative Example 1 was used instead of the fiber obtained in Example 1, and the properties were evaluated. The results are collectively shown in Table 5.

[Embodiment 6]

Using the polyester fiber obtained in Example 1, the following yarns were obtained by twisting 200 T/m and having a number of turns of 120 T/m to obtain a rope of 1100 dtex/2/3 (fiber material for belt reinforcement). After attaching the epoxy/isocyanate as a treatment agent to the rope, heat treatment was performed at 160 ° C for 60 seconds, and heat treatment was performed at 245 ° C for 80 seconds to further attach RFL (resorcinol. Formalin. Latex). This rope was heat-treated at 160 ° C for 60 seconds, and heat-treated at 235 ° C for 60 seconds. Using the obtained rope as a core wire, and making The V-shaped conveyor belt 1 is taken out. The conveyance belt tension maintenance ratio of the obtained V-shaped conveyor belt, the conveyor belt dimensional change rate, and the result of the shoe-shoe measurement are summarized in Table 6.

[Examples 7, 8, and Comparative Examples 6 to 9]

A V-shaped conveyor belt was produced in the same manner as in Example 6 except that the fibers of Examples 3 and 4 and Comparative Examples 1 to 4 were used instead of the fibers obtained in Example 1, and the properties were evaluated. The results are shown together in Figures 6 and 7.

[Embodiment 9]

The fiber obtained in Example 1 was immersed in resorcinol. Fomalin. The latex-based adhesive was dried in a gas atmosphere at 175 ° C for 1 minute, and then heat-treated in a gas atmosphere at 230 ° C for 2 minutes. The subsequently treated polyester fiber obtained in this manner was cut by a cutter to obtain a polyester staple fiber having a fiber length of 3.0 mm.

The polyester reinforcing short fiber was blended into an unvulcanized rubber containing natural rubber and styrene butadiene as a main component, and a MS type pressure kneader (DS3-10MHHS, Moriyama Manufacturing Co., Ltd.) was used. Limited company System) mixed for 3 minutes. The sheet was calendered at an appropriate thickness to align the staple fibers, and a rubber sheet was produced by calendering and vulcanization, and a sample was cut out in the direction of the alignment of the short fibers to prepare a short fiber-reinforced rubber molded article, and the properties were evaluated.

As a result, as shown in Table 8, the tensile strength at the point of depression was 14.0 kg/cm ² and the bending fatigue life was 166,000 times, and excellent effects were obtained in both the reinforcing property and the fatigue resistance.

[Examples 10 and 11, Comparative Examples 10 to 13]

A short fiber reinforced rubber molded article was produced in the same manner as in Example 9 except that the fibers of Examples 3 and 4 and Comparative Examples 1 to 4 were used instead of the fibers obtained in Example 1, and the properties were evaluated. The results are shown together in Tables 8 and 9.

1‧‧‧V belt

2‧‧‧With rubber cloth

3‧‧‧core

4‧‧‧Next rubber layer

5‧‧‧Compressed rubber layer

6‧‧‧ Short fiber

7‧‧‧ Ribs

8‧‧‧ Rib type V conveyor belt

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing one embodiment of a conveyor belt using a cord of the present invention as a core.

Fig. 2 is a cross-sectional view showing another example of a conveyor belt using the cord of the present invention as a core.

1‧‧‧V belt

2‧‧‧With rubber cloth

3‧‧‧core

4‧‧‧Next rubber layer

5‧‧‧Compressed rubber layer

6‧‧‧ Short fiber

Claims (10)

A polyester reinforcing polyester fiber characterized by comprising a polyester composed of polyester having an intrinsic viscosity of 0.85 or more with ethylene terephthalate as a main repeating unit, and the amount of terminal carboxyl groups in the fiber is 20 equivalents. Above /ton, the long-period system measured by X-ray small angle diffraction is 9 to 12 nm, and a surface treatment agent having an epoxy group is attached to the surface of the fiber. The polyester fiber for rubber reinforcement according to the first aspect of the invention, wherein the amount of terminal carboxyl groups on the surface of the fiber is 10 equivalents/ton or less. The polyester fiber for rubber reinforcement according to the first aspect of the patent application, wherein the crystal size in the transverse direction of the fiber is 35 to 80 nm ² . The polyester fiber for rubber reinforcement according to the first aspect of the patent application, wherein the terminal methyl group in the fiber is 2 equivalent/ton or less. The polyester fiber for rubber reinforcement according to the first aspect of the patent application, wherein the content of the titanium oxide in the fiber is 0.05 to 3% by weight. The polyester fiber for rubber reinforcement according to the first aspect of the patent application, wherein the epoxy index of the fiber surface is 1.0 × 10 ^-3 equivalent / kg or less. A method for producing a polyester fiber, characterized in that a polyethylene terephthalate polymer having an intrinsic viscosity of 0.9 or more and a terminal carboxyl group content of 15 equivalent/ton or more is melt-extruded, and an epoxy hardening contact is added thereto. After the spinning oil of the medium, the mixture is drawn at a speed of 2000 to 6000 m/min, and then extended, and then a finishing oil containing an epoxy compound is added to perform a ripening treatment. The method for producing a polyester fiber according to claim 7, wherein the ripening treatment temperature is in the range of 20 to 50 °C. The method for producing a polyester fiber according to claim 7, wherein the ripening treatment time is 50 hours or longer. A method for producing a polyester fiber according to claim 7, wherein the epoxy hardening catalyst is an amine compound.