JPH04327214A - Conjugate fiber - Google Patents

Abstract

PURPOSE:To provide a conjugate fiber for industrial use having excellent heat- resistance, chemical resistance, durability and mechanical properties and high peeling resistance between the inner layer polymer component and the outer layer polymer component. CONSTITUTION:The conjugate fiber has an innermost layer made of a polyethylene terephthalate (PET), an outermost layer made of a polyphenylene sulfide (PPS) and an intermediate layer made of a blend of PET and PPS. The amounts of the innermost layer and the outermost layer are >=20wt.% and >=10wt.% based on the total fiber, respectively. A blend of PET and PPS at a ratio of 30:70 to 70:30 in the intermediate layer accounts for 5-50wt.% of the total fiber.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to composite fibers with excellent heat resistance, chemical resistance, durability, and mechanical properties. The invention relates to composite fibers that are significantly improved compared to fibers.

0002

BACKGROUND OF THE INVENTION In recent years, polyphenylene sulfide has attracted attention as a high-performance engineering plastic due to its excellent heat resistance and chemical resistance.

[0003] Polyphenylene sulfide fibers have excellent heat resistance and chemical resistance, so they can be used as various industrial fibers, such as bag filter scrim base fabrics, motor tying cords, motor binder tapes, and rubber reinforcing fibers. It is considered.

[0004] However, polyphenylene sulfide fiber is characterized by its low mechanical properties as an industrial fiber. Therefore, if the mechanical properties of polyphenylene sulfide fiber are improved, it is expected that its application to various industrial uses as described above will be expanded.

[0005]Although polyphenylene sulfide fiber has excellent heat resistance and chemical resistance, its price is several times higher than general-purpose nylon fiber or polyethylene terephthalate fiber, so there is a desire to reduce the price. . In order to meet this requirement, composite fibers of polyphenylene sulfide polymer and inexpensive polyethylene terephthalate polymer have been proposed in JP-A-59-204920 and JP-A-2-99614.

However, in the conventional manufacturing technology of composite fibers, if the core component and sheath component polymers are incompatible with each other, or if the polymers are incompatible with each other, the core and sheath components may not be compatible even if they are made into composite fibers. The peeling durability of the sheath interface is poor,
Because it cannot maintain strength and fatigue resistance, it has rarely been used as an industrial fiber.

[0007] Therefore, in the above-mentioned JP-A-59-204920 and JP-A-2-99614, polyphenylene sulfide polymer and polyethylene terephthalate polymer, which have poor compatibility with each other, are blended in the core or sheath. It has been proposed to improve the peeling durability of the core-sheath interface, but although this method improves the peeling durability, the polymer blend causes problems as described below, making it difficult to use as an industrial fiber, which is the original purpose. The problem is that heat resistance, chemical resistance, durability, and mechanical properties are not sufficiently improved.

[0008] That is, the above-mentioned Japanese Patent Application Laid-Open No. 59-204920
The publication describes a composite fiber using a polyethylene terephthalate polymer as a core component and a blend polymer of a polyphenylene sulfide polymer and a polyethylene terephthalate polymer as a sheath component. However, this method has the problem that a part of the polyethylene terephthalate polymer, which has poor heat resistance and chemical resistance, is exposed to the surface layer of the fiber, so the heat resistance and chemical resistance do not improve as much as expected. was.

[0009] Furthermore, in Japanese Patent Application Laid-Open No. 2-99614,
A composite fiber is described that uses a blend polymer of polyphenylene sulfide polymer and polyethylene terephthalate polymer as the core component and polyphenylene sulfide polymer as the sheath component, but since the core component polymer is composed of a blend polymer of polyphenylene sulfide polymer and polyethylene terephthalate polymer, The mechanical properties of the fibers are poor, especially the tensile strength is less than 5 g/d, and there has been a problem that the fibers cannot be provided as industrial fibers that require strength.

0010

SUMMARY OF THE INVENTION The present invention was achieved as a result of studies aimed at solving the problems of the conventional composite fibers mentioned above.

[0011] Therefore, an object of the present invention is to solve the problems of
Compared to the composite fiber described in the publication, the peeling durability between the core component and the sheath component is greatly improved, and it also has excellent heat resistance, chemical resistance, and high mechanical properties, that is, high strength and high elongation. The object of the present invention is to provide a composite fiber suitable as an industrial fiber having bending fatigue resistance.

0012

[Means for Solving the Problems] The structure of the present invention is such that the innermost layer consists of a polyethylene terephthalate component having an intrinsic viscosity [η] of 0.5 or more, and the outermost layer consists of a polyphenylene sulfide component, and the innermost layer and the outermost layer A conjugate fiber consisting of at least three layers having an intermediate layer in which the polyethylene terephthalate component and the polyphenylene sulfide component are mutually dispersed and mixed; The ratio of polyphenylene sulfide to the entire composite fiber of the outermost layer in which polyethylene terephthalate is not substantially dispersed and mixed is 10% by weight or more, and B. The ratio of polyphenylene sulfide of polyethylene terephthalate to the entire conjugate fiber of the innermost layer in which polyethylene terephthalate is not substantially dispersed and mixed is 20% by weight or more, and C.I. The ratio of the intermediate layer in which polyphenylene sulfide and polyethylene terephthalate are mutually dispersed and mixed accounts for 70% by weight or less in the entire composite fiber, and the ratio of polyphenylene sulfide and polyethylene terephthalate in this intermediate layer is 30:70 to 70:30. The proportion of the mutually dispersed and mixed parts in the total weight ratio of the composite fibers is 5 to 5.
0% by weight, D. The composite fiber has a strength of 5.5 g/denier or more.

[0013]

[Embodiment] The composite fiber according to the present invention has the above-mentioned structure, but in particular, the innermost layer component and the outermost layer component are This can be achieved by appropriately providing an intermediate layer in which the innermost layer component and the outermost layer component are dispersed and mixed with each other.

The innermost layer component of the composite fiber according to the present invention is polyethylene terephthalate (hereinafter referred to as PET) consisting essentially of ethylene terephthalate units, but PE
The copolymer component may be contained to an extent that does not substantially reduce the physical and chemical properties of the T polymer, for example, less than 10%. Copolymerization components include dicarboxylic acids such as isophthalic acid and diphenyldicarboxylic acid, and propylene glycol.
Examples include diol components such as butylene glycol,
Copolymerization components other than those listed above may also be used.

In order to make the strength of the composite fiber according to the present invention 5.5 g/denier or more, the intrinsic viscosity [η] of the PET polymer as the innermost layer component should be 0.5 or more, preferably 0. It is necessary to regulate the viscosity to be as high as .6 or higher.

The outermost layer component of the composite fiber according to the present invention is polyphenylene sulfide (hereinafter referred to as PPS). As a PPS polymer, the melt flow rate (MFR
) of 10 to 600 is used, but
A crosslinked polymer containing 0.1% by weight or less of trichlorobenzene (TCB) may also be used.

[0017] Melt flow rate (MFR) here
is AS with a measurement temperature of 316℃ and a load of 5Kgf.
Means the melt flow of the polymer as measured by the TM D1238-82 method.

In the composite fiber according to the present invention, the proportion of the PPS component, which is the outermost layer component, in the entire composite fiber, that is, the proportion in the total cross-sectional area of the composite fiber, is 10% by weight or more, and the outermost layer component contains Substantially no PET components are dispersed and mixed.

In the composite fiber according to the present invention, the proportion of the PET component, which is the innermost layer component, in the total composite fiber is 20% by weight.
This is the above, and the PPS component is not substantially dispersed and mixed in this innermost layer component.

[0020] When the proportion of the PPS component, which is the outermost layer component, of the composite fiber according to the present invention is less than 10% by weight in the total composite fiber, the heat resistance and chemical resistance are lower than that of bag filter scrim base fabric, motor knot, It has not been improved to the point where it can be used as industrial fibers such as motor binder tape and rubber reinforcing fibers.

In the composite fiber according to the present invention, when the proportion of the PET component, which is the innermost layer component, in the entire composite fiber is less than 20% by weight, the strength of the composite fiber is 5.5 g, which is the target value of the present invention. /Denier or higher strength cannot be achieved.

[0022] In the composite fiber according to the present invention, the ratio of the intermediate layer between the innermost layer component and the outermost layer component, in which the PPS component and the PET component are mutually dispersed and mixed, to the total composite fiber is 70% by weight. It is as follows. This intermediate layer is composed of PET polymer and PPS polymer in a weight ratio of 30:70 to 70:3.
It is mainly composed of layers that are dispersed and mixed with each other at a ratio of 0. The ratio of the intermediate layer having the above-mentioned mixing ratio to the total composite fibers is preferably in the range of 5 to 50%. P
If the ratio of the intermediate layer in which ET and PPS are dispersed and mixed in the above ratio exceeds 50% of the entire composite fiber, the characteristics of the composite fiber of the present invention, namely heat resistance, chemical resistance, and mechanical properties, will deteriorate. On the other hand, if the amount is less than 5%, the effect of improving the peeling durability between the innermost layer and the outermost layer, which is a feature of the present invention, is recognized, but it may not be possible to use it for the various industrial fibers mentioned above. This is not desirable because it may not lead to this.

The composite fiber according to the present invention having the above-mentioned characteristics is produced by the novel method shown below.

The innermost layer component of the composite fiber according to the present invention is a PET polymer consisting essentially of ethylene terephthalate units and having an intrinsic viscosity [η] of 0.5 or more, usually 0.6 or more.

PP as the outermost layer component of the composite fiber according to the present invention
S polymer has a melt flow rate (MFR) of 10 to 6.
A substantially linear polymer of 0.00 is used, but a crosslinked polymer containing 0.1% by weight or less of trichlorobenzene (TCB) may also be used.

The intermediate layer formed between the innermost layer component and the outermost layer component is formed by dispersing and mixing the innermost layer component polymer and the outermost layer component polymer in a weight ratio of 30:70 to 70:30. , and in order to maintain a stable ratio of 10 to 50% of this intermediate layer in the total fiber, it is necessary to: ■ Make both the PPS polymer and PET polymer that form the intermediate layer into chips, and use these chips in the spinning process. After melting the innermost layer component and outermost layer component polymer, the innermost layer component polymer and outermost layer component polymer are mixed in a kneading device installed before the pack introduction section. A method in which a part of the innermost layer polymer and the outermost layer polymer are melted and then introduced into a die pack, and a part of the innermost layer polymer and the outermost layer polymer are mixed in the die. Examples include a method of kneading some of the ingredients.

Specifically, for example, in the case of method (2) above,
PET polymer as the innermost layer component, PP as the outermost layer component
Three extruder-type spinning machines are used for melt spinning the blend polymer to form an intermediate layer in which S polymer, PET polymer, and PPS polymer are mutually dispersed and mixed.

[0028] In order to form an innermost layer component PET polymer, an outermost layer component PPS polymer, which were independently melted using three extruder type spinning machines, and an intermediate layer in which the PET polymer and PPS polymer were mutually dispersed and mixed. The three blended polymers are each introduced into a composite spinning pack and passed through a composite spinning nozzle to form an innermost layer of PET, an intermediate layer between the innermost layer component and the outermost layer component in which PET and PPS are mutually dispersed and mixed. It is spun as a three-layer composite fiber with PPS arranged in the outermost layer.

[0029] The spinning speed is 500 m/min or more. A heat insulating tube or a heating tube is provided directly below the spinneret, and a heating atmosphere is created at 180° C. or more and 350° C. or less over a distance of 5 cm or more and 50 cm or less, and the spun yarn immediately after spinning is heat-treated.

[0030] When spinning is performed without providing the above-mentioned heating atmosphere directly under the spinneret, it is difficult to stably spin and draw a particularly thick yarn for industrial use to obtain a high-strength fiber.

After passing through the heated atmosphere, the spun yarn is quenched and solidified with cold air, then applied with an oil agent, and then taken off by a take-off roll that controls the spinning speed to become an undrawn drawn yarn.

[0032] The undrawn yarn is usually drawn continuously without being wound up once, or the undrawn yarn is once wound up and then drawn in a separate step.

[0033] When the undrawn yarn is drawn continuously without being wound once, multistage drawing of two or more stages is usually used. The stretching ratio is 2.0 to 6.3 times depending on the spinning conditions. When two-stage stretching is used, the first stage stretching is 70% or more of the total stretching ratio, usually 78 to 88%, and the remainder is carried out in the second stage stretching. The maximum stretching temperature is 160-250
℃. If the maximum drawing temperature is less than 160°C, it will not be possible to draw at a high magnification and a high strength yarn will not be obtained, and if it exceeds 250°C, the drawability will decrease and single filament breakage will occur, making it difficult to obtain high quality composite fibers. Can not.

The structure and effects of the conjugate fiber of the present invention will be explained in more detail with reference to examples below. The fiber properties and measuring methods of the conjugate fiber in the following examples are as follows.

Characteristics of composite fiber (a) Strength (g/d), elongation (%): Strength and elongation are JI
Based on the definition and measurement method of S-L1017.

[0036] The specific conditions for the tensile test to obtain the SS curve are as follows.

[0037] A sample was taken in the shape of a skein, and after being left in a temperature-controlled room at 20°C and 65% RH for more than 24 hours, it was tested using a tensile tester of the type "Tensilon UTL-4L" (manufactured by Orientec Co., Ltd.). Measurement was performed with a sample length of 25 cm and a tensile speed of 30 cm/min.

(b) Alkali resistance strength retention rate (%): Multifilament composite fibers were treated at 95° C. for 100 hours in an NaOH aqueous solution having a concentration of 40% by weight, and the alkali resistance was evaluated based on the strength retention rate. Alkali resistance strength retention rate = strength after treatment / strength before treatment × 100 (c) Acid resistance strength retention rate (%): H2 at a concentration of 40% by weight
In SO4 aqueous solution, 9 composite fiber multifilaments
The samples were treated at 5° C. for 100 hours, and acid resistance was evaluated based on strength retention. Acid resistance strength retention rate = strength after treatment / strength before treatment x 10
0 (d) Heat resistance strength retention rate (%): 150°C, 2.0Kg
1 multifilament of composite fiber in moist heat of /cm2
The heat resistance was evaluated based on the strength retention rate. Heat resistance strength retention rate = strength after treatment / strength before treatment x 10
0 (e) Peeling resistance: 6
An electron microscope photograph of the multifilament which was twisted at 0 T/dm and then untwisted was taken, and the peeling state of the innermost layer component and the outermost layer component was evaluated from the photograph.

[0039]

【Example】

Examples 1 to 3, Comparative Examples 1 and 2 A PET polymer with an intrinsic viscosity [η] of 0.9 and a PPS polymer with a melt flow rate of 300 were each melted in a 40Φ extruder type spinning machine, and the PET polymer and the PPS polymer were melted using a 40Φ extruder type spinning machine. The blended polymer with the polymer is melted using a 30Φ extruder type spinning machine, and these three types of polymers are introduced into a composite pack, and the innermost layer is blown using a three-layer core-sheath composite spinneret.
ET, the innermost layer component P is in the boundary layer between the innermost layer component and the outermost layer component.
An intermediate layer in which ET and outermost layer component PPS are mutually dispersed and mixed;
It was spun as a composite fiber with a three-layer structure in which PPS was arranged as the outermost layer component. Table 1 shows the proportions of the innermost layer component, the intermediate layer in which the innermost layer component and the outermost layer component are mutually dispersed and mixed, and the outermost layer component. The spinneret has a hole diameter of 0.6 mmΦ and a number of holes of 120.
Using Hall's, PET and PP were heated at 295℃.
The blend polymer of S and PPS were melted at 315°C and 330°C, respectively, and spun at a spinning pack temperature of 310°C. A 20 cm heating cylinder was attached directly below the mouthpiece, and the atmosphere inside the cylinder was heated to 320°C. The atmosphere temperature inside the cylinder is the atmosphere temperature measured at a position 10 cm below the mouth surface and 1 cm away from the outermost thread. An annular chimney with a length of 40 cm was installed under the heating cylinder, and cold air was blown at 40 m/min at 25° C. from around the yarn at right angles to the yarn to cool it. Next, an oil agent was applied, and Table 1
After controlling the yarn speed with a take-up roll rotating at the speed shown in , the yarn was drawn continuously without being wound up. Stretching is 3
After stretching in two stages using a pair of Nelson rolls, the film was wound up with 3% relaxation between the next Nelson rolls. The temperature of the take-up roll was set to 60°C, and the first stage of stretching was performed between the take-up roll and the first stretching roll heated to 100°C.
A second stage of stretching was performed between the stretching roll and a second stretching roll heated to a predetermined temperature. The following Nelson roll was used for tension adjustment after unheated stretching. The first stage stretching ratio was 78% of the total stretching ratio, and the remainder was stretched in the second stage. Silk production was carried out by varying the spinning speed, total draw ratio, etc., and the discharge amount was varied in accordance with the spinning speed and draw ratio so that the fineness of the drawn yarn was about 500 denier. The spinning conditions, the obtained drawn yarn characteristics, and other physical properties are as shown in Table 1.

[0040]

[Table 1]

[0041]

[Effects of the Invention] The composite fiber according to the present invention has excellent heat resistance and chemical resistance, and has higher strength and elongation than PPS fibers. By forming an intermediate layer in which the polymer and the outermost layer component polymer are mutually dispersed and mixed, the peel durability of the interface between the innermost layer and the outermost layer is significantly improved, and the fatigue resistance is particularly excellent. .

[0042] Therefore, the composite fiber according to the present invention is suitable for various industrial material applications that take advantage of the above-mentioned characteristics, such as bag filter scrim base fabric, motor tying cord, motor binder tape, and rubber reinforcing fiber.

Claims (1)

[Claims] 1. The innermost layer consists of a polyethylene terephthalate component having an intrinsic viscosity [η] of 0.5 or more, the outermost layer consists of a polyphenylene sulfide component, and the polyethylene terephthalate component and the polyphenylene sulfide are disposed between the innermost layer and the outermost layer. A conjugate fiber consisting of at least three layers having an intermediate layer formed by mutually dispersed mixing of A. The ratio of polyphenylene sulfide to the entire composite fiber of the outermost layer in which polyethylene terephthalate is not substantially dispersed and mixed is 10% by weight or more, and B
．． The ratio of polyphenylene sulfide of polyethylene terephthalate to the entire conjugate fiber of the innermost layer in which polyethylene terephthalate is not substantially dispersed and mixed is 20% by weight or more, and C.I.
The ratio of the intermediate layer in which polyphenylene sulfide and polyethylene terephthalate are mutually dispersed and mixed accounts for 70% by weight or less in the entire composite fiber, and the ratio of polyphenylene sulfide and polyethylene terephthalate in this intermediate layer is 30:70 to 70:30. D. The proportion of the mutually dispersed and mixed parts in the weight ratio of the whole composite fiber is 5 to 50% by weight; A composite fiber characterized in that the strength of the composite fiber is 5.5 g/denier or more.