JPH0362806B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to aromatic polyetherketone fibers, and more specifically, aromatic polyetherketone fibers that have excellent tensile strength and knot strength and are preferably used for industrial applications. It concerns fibers.

[Prior Art] One type of fiber with excellent heat resistance and chemical resistance is wholly aromatic polyamide fiber. This fiber is usually obtained by wet spinning or dry spinning.

[Problem to be solved by the invention] In order to obtain the aromatic polyamide fiber with excellent heat resistance and chemical resistance, special equipment is required compared to the melt spinning method, and it takes a long time to obtain the final fiber. It is quite difficult to handle it.

Therefore, the object of the present invention is to obtain a fiber made of a polymer that can be melt-processed and has excellent heat resistance, and also to create an aromatic fiber that does not thermally decompose the polymer with a high melting temperature, and has the potential for mechanical properties as an industrial fiber. An object of the present invention is to provide fibers made of polyetherketones.

[Means and effects for solving the problems] The present invention has the following features: (1) In the aromatic polyetherketone fiber, 80 mol% or more of the repeating structural units have the formula An aromatic polyetherketone fiber obtained by melt-spinning a polymer consisting of an aromatic polyetherketone having an intrinsic viscosity of 0.7 or more and consisting of units represented by the following: Aromatic polyetherketone having a tensile strength of 4.0g/d or more An aromatic polyetherketone fiber characterized by having a tensile strength of 4.0 g/d or more and a knot strength of 3.0 g/d or more, (2) (1) above. In the aromatic polyetherketone fiber described in 1., the aromatic polyetherketone fiber is characterized in that the fiber is a monofilament having a diameter of 0.1 to 0.8 mm.

The aromatic polyetherketone fiber according to the present invention is obtained by melting an aromatic polyetherketone polymer and melt-spinning it through a spinneret to obtain a spun yarn, and then passing the spun yarn into a heating cylinder provided directly below the spinneret. of
After passing through a gas atmosphere heated to a temperature of 300 to 700°C, the spun yarn that passed through the heating cylinder was cooled and solidified, and then the cooled and solidified spun yarn was heated to 150°C.
It is obtained by stretching 3.0 times or more in or in contact with a heating medium heated to the melting point temperature of the polymer.

The present invention is particularly effective when a monofilament with a diameter of 0.1 to 0.8 mm is obtained, and the monofilament has a knot strength of 3.0 g/d or more.

Hereinafter, the present invention will be specifically explained in detail.

First, an aromatic polyetherketone polymer is prepared. The aromatic polyetherketone polymer is a polymer in which 80 mol% or more of the repeating structural units are represented by the above formula (), and this is a polymer that is described in the Journal of
Polymer Science Part A-1, Vol.5, P.2394
(1967), it is a known polymer. It is also a high melting point polymer with the characteristics of glass transition point 160℃ and melting point 350℃. However, in order to be suitable for fiber applications, a certain degree of polymerization is required, with an intrinsic viscosity (IV) of 0.7 or more,
Preferably, a polymer having an intrinsic viscosity (IV) of 1.0 or more is used as a raw material. At this time, the intrinsic viscosity (IV) is the intrinsic viscosity calculated by dissolving 0.1 g of polymer per 100 c.c. of concentrated sulfuric acid and measuring at 25°C.

Next, the polymer is melt-spun.

As mentioned above, the polymer used in the present invention has a high melting point and high melt viscosity, so it has a high melting point and a high melt viscosity.
It cannot be spun using equipment that melts and spins polymers at temperatures of 120 to 270°C. For example, even if you try to spin the spinning machine by raising the spinning temperature to around 400℃ using a spinning machine that takes into account materials such as heaters or seal packing materials that have little thermal deformation, the spun yarn spun from the spinneret will have a high viscosity and the spinning temperature will increase. Since there is a large difference between the temperature of the spun yarn and the temperature of the spinneret, the spun yarn cannot be taken off at a high speed due to sudden cooling.

As a result of various studies, the polymer is preferably melt-spun at a temperature of 380 to 430°C.
If the temperature is lower than 380°C, the melt viscosity will be significantly high and the spinnability will be reduced, while if the temperature is higher than 430°C, unevenness may occur in the spun yarn directly under the spinneret.

A heating cylinder is provided directly below the cap, and the temperature inside the heating cylinder is placed in an unusually high-temperature gas atmosphere, that is, a high-temperature atmosphere of 300 to 700°C, preferably a high temperature heated to 350 to 550°C. The spun yarn spun from the die is passed through an atmosphere, more preferably a high temperature atmosphere consisting of nitrogen, to reduce the viscosity of the spun yarn and delay solidification by cooling, and then the heating The molten spun yarn that has passed through the cylinder is cooled and solidified, and then the cooled and solidified spun yarn is heated to 150°C to the melting point of the polymer in a heating medium or in contact with a heating medium to a temperature of 3.0 times or more. By drawing, a high-strength aromatic polyetherketone fiber was obtained.

The heating cylinder has a shape that heats the hollow portion from the periphery, and the spun yarn passes through the heated hollow portion.

If the above-mentioned spinning tube is not provided, the spinning speed must be extremely low, and the spinning speed may be 5 to 60 m/min.
Even at a low speed of 1 min, thread breakage occurs during drawing, making it impossible to obtain fibers of good quality and poor productivity. Furthermore, if the temperature of the hollow part of the spinning tube is lower than 300°C, the stretching ratio cannot be set to a high ratio, and a fiber made of aromatic polyetherketone with high strength cannot be produced.

Meanwhile, the temperature of the hollow part of the spinning tube was set to 700.
When the temperature is higher than 0.degree. C., there are disadvantages in that the viscosity of the spun yarn decreases and the polymer decomposes, resulting in decreased spinning and spinnability during spinning.

The temperature of the hollow part of the spinning tube is set at 350 to 550°C as conditions for producing a fiber made of aromatic polyetherketone with high tenacity by performing the above-mentioned spinning properties and drawing properties during spinning and high-strength drawing. It is preferable to control the

The spun yarn that has been spun from the spinneret and passed through the hollow part of the spinning tube is cooled, solidified, and then drawn. Cooling and solidification can be carried out by appropriately selecting the cooling and solidification equipment and conditions used in ordinary melt spinning.

The fiber made of aromatic polyetherketone is
Hot drawing is carried out at a temperature controlled between 150°C and the melting point of the polymer. If the fiber made of aromatic polyetherketone is a monofilament with a diameter of 0.1 to 0.8 mm, a heating medium made of liquid is used for drawing. It is stretched by 3.0 times or more while in contact with a heating medium in a bathtub. As the heating medium, for example, polyethylene glycol is preferably used.

The temperature of the heating medium is controlled between 150°C and the melting point of the polymer. If the temperature is lower than 150°C, it may be difficult to increase the draw ratio to 3.0 times or more, but by setting the draw ratio to higher than 150°C, a highly strong aromatic polyetherketone monofilament can be obtained. . If the temperature of the heating medium is higher than the melting point of the polymer, there will be a disadvantage that the monofilament will melt in the heating medium.

That is, the novel method for producing aromatic polyetherketone fibers according to the present invention involves using an aromatic polyetherketone (polymer) with an intrinsic viscosity of 0.7 or more, and placing the spun yarn obtained by melt spinning directly under the spinneret. passing through a gas atmosphere heated to a temperature of 300 to 700°C using a heating cylinder provided; cooling and solidifying the molten spun yarn that has passed through the heating cylinder; and cooling and solidifying the spun yarn that has been cooled and solidified. A high-strength aromatic compound is produced by the synergistic effect of satisfying each of the following conditions: Stretching 3.0 times or more in or in contact with a heating medium heated from 150°C to the melting point temperature of the polymer. A polyetherketone monofilament is obtained.

The aromatic polyetherketone fiber according to the present invention is particularly suitable for use in papermaking canvases, heat-resistant work clothes, gloves, bag filters, heat-resistant and chemical-resistant brushes, etc.
Suitable for applications requiring chemical resistance. When knitting and weaving aromatic polyetherketone monofilaments such as canvas for papermaking, bending strength characteristics of the yarn such as hooking are required, but knot strength is an indicator of the bending strength characteristics of this yarn. The characteristics
It is obtained by stretching an aromatic polyetherketone monofilament having a weight ratio of 3.0 g/d or more to 3.0 times or more. This is made possible by passing through a gas atmosphere heated to a temperature of 300 to 700°C using a heated cylinder.

Among the aromatic polyetherketone fibers according to the present invention, aromatic polyetherketone monofilaments having a diameter of 0.1 to 0.8 mm are particularly effective, and monofilaments exceeding 0.8 mm have the above-mentioned knot strength properties. may not reach 3.0g/d.

[Example] Example 1 A polymer with a repeating unit [] with an intrinsic viscosity (IV) of 1.4 was melted at 400°C, and the pore diameter was 1.0 mm, the number of pores was 1, and the outer diameter was
It was extruded from a 40 mm nozzle at a discharge rate of 1.9 g/min.
A heating cylinder with an inner diameter of 6 cm and a length of 20 cm was installed directly below the cap, and the gas atmosphere heated to 400°C was passed through the heating cylinder, and then the drawn yarn was cooled with water at 75°C. It was wound up at a speed of 15 m/min.

This partially drawn yarn was drawn in one step to 3.8 times in a polyethylene glycol bath at 200°C to obtain an aromatic polyetherketone monofilament. The characteristics of the monofilament were as follows.

Diameter (mm); 0.20 Fineness (D); 304 Tensile strength (g/d); 7.12 Tensile elongation (%); 13.9 Comparative example 1 Same as Example 1 without providing a heating tube and keeping all other conditions the same. As a result, the yarn could only be stretched up to 2.8 times in a polyethylene glycol bath heated to 200°C. The properties of the aromatic polyetherketone monofilament obtained at a stretching ratio of 2.8 times were as follows.

Diameter (mm); 0.24 Fineness (D); 415 Tensile strength (g/d); 3.4 Tensile elongation (%); 24.0 Example 2 Same polymer, melting temperature, heating tube as Example 1,
Aromatic polyether ketone monofilament was obtained by spinning the undrawn monofilament obtained by changing the cooling rate and winding speed to 1.23 g/min, and then drawing the resulting end-drawn monofilament to 3.8 times in a polyethylene glycol bath at 200°C. I got it. The properties of the obtained monofilament were as follows.

Diameter (mm); 0.14 Fineness (D); 195 Tensile strength (g/d); 7.74 Tensile elongation (%); 12.8 Knot strength (g/d); 5.57 Knot elongation (%); 10.0 Comparative example 2 Comparison As in Example 1, the heating cylinder was not provided, and all other conditions were the same as in Example 2, resulting in yarn spinning.
In a polyethylene glycol bath heated to 200°C, it could only be stretched up to 2.8 times. Stretching ratio
The properties of the aromatic polyetherketone monofilament obtained at a magnification of 2.8 times were as follows.

Diameter (mm); 0.19 Fineness (D); 270 Tensile strength (g/d); 3.6 Tensile elongation (%); 26.0 Knot strength (g/d); 1.5 Knot elongation (%); 13.0 Example 3 Implementation The drawn yarn obtained in Example 2 was further heat-treated for 1 minute at a constant length in a silicone bath at 300°C, and as a result, an aromatic polyetherketone monofilament having the following properties could be obtained.

Diameter (mm); 0.16 Fineness (D); 198 Tensile strength (g/d); 7.76 Tensile elongation (%); 18.6 Example 4 Using the same polymer as in Example 1, the melting temperature
400℃, mouth hole diameter 0.5mm, number of holes 3, atmosphere temperature inside the heating cylinder 400℃, air cooling, winding speed 25m/min,
Filtration was carried out under the same conditions as in Example 1 except for the other conditions, and an end-drawn aromatic polyetherketone monofilament was obtained.

The birefringence of the obtained end-stretched monofilament is
It was 1.60×10 ^-3 (using Na-D line). This end-stretched aromatic polyetherketone monofilament
It was brought into contact with a hot plate at 200°C and hot-stretched to 4.0 times.
The properties of the obtained drawn yarn were as follows.

Fineness (D); 99 Single yarn fineness (D); 33 Tensile strength (g/d); 7.85 Tensile elongation (%); 11.5 Example 5 Using the same polymer as in Example 1, the melting temperature
The powder was spun at 415°C at a rate of 2.0 g/min from a spindle with a diameter of 0.6 mm, two holes, and an outer diameter of 40 mm, passed through a heating cylinder with an inner diameter of 60 mm heated to a temperature of 430°C, and then cooled. The drawn yarn was wound at 300 m/min to obtain an end-drawn aromatic polyetherketone monofilament. This semi-stretched aromatic polyether ketone monofilament was brought into contact with a hot plate at 200°C and hot-stretched to 3.2 times. The properties of the obtained drawn yarn were as follows.

Tensile strength (g/d); 5.4 Tensile elongation (%); 22.0 Comparative Example 3 As in Comparative Example 1, the heating cylinder was not provided, but all other conditions were the same as in Example 5, and yarn spinning was performed.
Many spun yarn breakages occurred, and the obtained aromatic polyetherketone monofilament (end-drawn yarn) could not be wound.

[Effects of the Invention] According to the present invention, an aromatic polyether ketone polymer having excellent heat resistance can be efficiently obtained by a melt spinning method without thermal decomposition, and the aromatic polyether ketone obtained The fiber has excellent heat resistance and chemical resistance, as well as excellent tensile strength and knot strength, and has the potential for mechanical properties as an industrial fiber.

Claims (1)

[Claims] 1. In the aromatic polyetherketone fiber, 80 mol% or more of the repeating structural units have the formula An aromatic polyetherketone fiber obtained by melt-spinning a polymer consisting of an aromatic polyetherketone having an intrinsic viscosity of 0.7 or more and consisting of units represented by the following: Aromatic polyetherketone having a tensile strength of 4.0g/d or more A fiber having a tensile strength of 4.0 g/
An aromatic polyetherketone fiber characterized by having a knot strength of 3.0 g/d or more and a knot strength of 3.0 g/d or more. 2. The aromatic polyetherketone fiber according to claim 1, wherein the fiber has a diameter of 0.1 to
Aromatic polyetherketone fiber characterized by being a 0.8 mm monofilament.