Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/62—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters

Definitions

• This invention is related to polyester yarn which has high strength and excellent durability and is particularly suitable as a rubber-reinforcing material.
• the fiber made from polyethylene terephthalate, or from a polyester in which it is the main component, has excellent mechanical properties and thermal properties and it is widely used in the manufacture of tire cords, V belts, conveyor belts and hoses. In particular it takes the largest ratio in the application as the rubber-reinforcing material where polyester fibers of high strength and excellent durability with balanced heat shrinkage and modulus are required.
• polyester fiber when used as the rubber-reinforcing material, it is necessary to subject it to a twisting process and a dip process (process of applying adhesive and heat-treating). Thus, even if the original yarn has good performance, the resultant dipped cord frequently cannot satisfy the required performance.
• This invention seeks to provide a polyester fiber which has a high strength and excellent durability with balanced heat shrinkage and modulus and which exhibits excellent performance even after being made into a dipped cord.
• Polyester yarn which is made from polyethylene terephthalate or from a polyester in which polyethylene terephthalate is the main component, the polyester fiber satisfying the following property characteristics (a) - (f) simultaneously.
• the polyester in this invention is polyethylene terephthalate or a polyester in which polyethylene terephthalate is the main component (at least 90 mol percent) and various types of dicarboxylic acid and glycol component can be copolymerized therewith in an amount of up to about 10 mol percent.
• polyethylene terephthalate is the main component (at least 90 mol percent) and various types of dicarboxylic acid and glycol component can be copolymerized therewith in an amount of up to about 10 mol percent.
• the polyester fiber of this invention must have a high molecular weight having an intrinsic viscosity of at least 0.91 as measured by 20°C by use of an equal weight mixed solvent of phenol and tetrachloroethane.
• an intrinsic viscosity of at least 1.0 is preferred. This is the required condition for the fiber to exhibit high strength and for increasing the formation of tie molecules which participate in the improvement of durability.
• the strength is the value obtained using the method of JIS L-1017, i.e., the value obtained by dividing the load at breaking in a load-elongation test with the measured denier determined prior to the test. It needs to be at leat 8.0 g/d, preferably at least 8.4 g/d.
• E 2.25 indicates the elongation at a load of 2.25 g/d in the load-elongation curve at the strength measurement.
• the value is obtained by computer treatment. It needs to be 4.5 percent or less, preferably 3.5 percent or less.
• a low value of this property means a high intermediate modulus, and it is a necessary condition for reducing the dip elongation phenomenon in the dip treatment process and for achieving high strength and high Young's modulus.
• ⁇ H mf is measured by use of Perkin Elmers DSC-2C differential scanning calorimeter with 3 mg of sample (original yarn) at a rate of temperature increase of 20°C/minute in a nitrogen atmosphere. It needs to be at least 11.5 cal/g, preferably at least 12.0 cal/g. This value depends on the degree of crystallization of the fibers and it indicates the degree of perfection of the microstructure of fibers mainly in the crystalline section. A large value of this indicates that the fiber has high strength, high modulus and high durability.
• the melting points of fiber are measured as follows: 3 mg of the monofilament of original yarn is wound over a copper plate of length 10mm, width 3 mm and thickness of 0.5 mm, under a load of 0.05 g/d or under no load, to a width of 5mm; the front end of the sample is tied and the excess copper plate is cut off; then, the measurement is made under the same conditions as in the measurement of ⁇ H mf .
• a copper plate of the same shape is inserted.
• TmF is the ordinary melting point and Tmf indicates the super-heating property caused by the tie molecules.
• the value of ⁇ T is an important indicator of the amount of tie molecules formed.
• the fiber having a high ⁇ T has a strong connection of the crystalline section and amorphous section by the tie molecules, and this contributes effectively to the prevention of breading phenomenon which occurs at the boundary between crystalline and amorphous sections; as the result, high strength and high durability are exhibited.
• ⁇ n is determined by the Berek compensator method using an ordinary polarized microscope.
• f c is obtained from the following equation with the average orientation angle ⁇ measured by wide angle X ray diffraction, i.e.
• the f c of the polyester fiber of this invention there is no particular restriction but it generally exhibits a value of about 0.94.
• the value of X is generally about 0.40 to 0.45.
• the polyester fiber of this invention which satisfies the above-mentioned characteristics simultaneously has high strength and excellent durability and also has a balanced heat shrinkage and modulus. Even after being made into the dipped cord, it exhibits excellent performance.
• molten polyester of high intrinsic viscosity (at least 0.91) from a polycondensation apparatus is directly fed to a spinning machine or is first made into chips which are melted in an extruder and then is fed to a spinning machine.
• Spinning is effected in a manner known per se at a take-up rate of about 700 to 5000 m/minute.
• a polyester of somewhat higher viscosity than the desired intrinsic viscosity of the polyester in the fiber to be obtained is used.
• the stress on the spun yarn is 0.05 to 1.0 g/d.
• the method of increasing the stress of spun yarn one can use a method involving increasing the spinning speed (take-up speed) or a method involving increasing the rate of cooling of the spun yarn. In this way, the birefringence of the resultant undrawn yarn is made to over 15 x 10 ⁇ 3, preferably 25 x 10 ⁇ 3 to 70 x 10 ⁇ 3.
• this undrawn yarn is drawn in one stage or multiple stages while heating by heating roller, heating plate, steam jet.
• Drawing can be done by a spin draw method which is conducted as a continuation of the spinning or by a two-process method in which the undrawn yarn is first taken up and then drawn subsequently.
• an optimal condition is selected by combining the spinning stress at spinning and the drawing temperature and time.
• N-glycidyl phthalimide was added in an amount indicated in Table 1. This was fed to an extruder type melt spinning machine and was spun at a spinning temperature of 300 to 310°C (set to the optimal temperature in this range) using a spinning die having 252 holes of diameter 0.6 mm. Spun yarn was passed through a heated hood of 100 mm length at an atmosphere temperature of 300°C. Then, cooling air at 18°C was blown from the circumferential direction at 40 m/minute velocity over a length of 300 mm. Spinning oil agent was applied by use of an oiling roller.
• Birefringence of the undrawn yarn was measured by unheating the take-up roller and winding the undrawn yarn on this and taking a sample from this.
• the yarn was given a first stage drawing to a draw ratio of 1.45 between the above-mentioned heated take-up roller and an unheated No. 1 Nelson roller.
• the yarn was passed through 400°C steam jet apparatus to effect a second stage drawing.
• the yarn was subjected to a relation at a ratio as shown in Table 1.
• the yard is then wound up.
• the draw ratio in second stage drawing was adjusted to give a total draw ratio as indicated in Table 1 taking the relaxation ratio into consideration.
• the denier change produced by changing the relaxation ratio of drawn yarn was adjusted by adjusting the extrusion rate.
• the end carboxyl group content in the drawn yarn obtained was in the range of 9.5 to 10.8 g/eq/106 polymer in all cases.
• downward twisting of 49 twists/10 cm was applied in the Z direction by use of a ring twisting machine.
• two yarn strands were combined and upward twisting of 49/10 cm in S direction was applied to make a greige cord. This was dip-treated by use of a single dipping machine made by the Litzler Company to obtain a dipped cord.
• a mixed solution consisting of 83 weight parts of resorcinol-formalin-Gentac latex solution (1 weight part of the reaction product of resorcinol and fomaldehyde in a mol ratio of 1:1.2, mixed with 4.3 weight parts, in solid content, of latex to prepare a solution having 20 weight percent concentration; pH adjusted to 9.5 with NaOH) and 17 weight parts of Vulcabond E.
• Gentac latex is a trade name of General Tire Company; it is a butadiene-styrene-vinyl pyridine latex.
• Vulcabond E is a trade name of Vulnax Company; it is an ammonia-water solution of 2,6-bis(2′,4′-dihydroxyl phenyl-4-chlorophenol having a solid content of 20 weight percent,
• polyester fibers which simultaneously satisfy the properties defined in this invention have excellent total balance of the strength, heat shrinkage, modulus and fatigue resistance in the dip cord performance which expresses the performance as rubber-reinforcing material directly. Thus, they are good as rubber-reinforcing materials; No. 5 - 8 have particularly good performance.
• This invention provides polyester fiber which has high strength and excellent durability and balanced heat shrinkage and modulus and is suitable as rubber-reinforcing material exhibiting excellent performance even after being made into dipped cord.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)

Applications Claiming Priority (2)

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Cited By (5)

Citations (4)

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• 1987
  • 1987-06-12 JP JP14763287A patent/JPS63315608A/ja active Pending
• 1988
  • 1988-06-13 DE DE19883883301 patent/DE3883301T2/de not_active Revoked
  • 1988-06-13 EP EP88305370A patent/EP0295147B1/de not_active Revoked

Patent Citations (4)

Non-Patent Citations (1)

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