JP2013537264A - Mixed fiber and method for producing the same - Google Patents

Abstract

Disclosed is a mixed fiber having excellent mechanical properties while being manufactured at a relatively low cost, and a manufacturing method thereof.
The mixed fiber of the present invention comprises a first filament; and a second filament different from the first filament; and the strength-elongation curve of the mixed fiber measured according to ASTM D 885. Has at least one peak, and when the intensity-elongation curve has two or more peaks, the first peak having the lowest elongation and the highest elongation among the two or more peaks. The elongation difference between the second peak and the second peak is 3% or less.
[Selection] Figure 1

Description

  The present invention relates to a mixed fiber and a method for producing the same, and more specifically to a mixed fiber having excellent mechanical properties while being produced at a relatively low cost and a method for producing the same.

  When producing a predetermined product using fibers, rather than producing the product only with expensive high-performance fibers, mixed fibers produced by mixing the expensive filaments with relatively low-value filaments are used. Thus, it may be advantageous to reduce the cost to produce the product.

  However, when different types of filaments having different characteristics are mixed by a normal method for producing a mixed fiber, the characteristics of the individual filaments are individually exhibited, so that no synergy effect is exhibited. For example, when an external force is applied to a mixed fiber made of different types of filaments having different elongations, not all filaments can both resist the external force, and filaments with relatively low elongation will resist first. Then, the filament having a relatively high elongation resists and is cut.

  Eventually, this mixed fiber can be advantageous in terms of manufacturing cost, but has a problem that it cannot have physical properties corresponding to expected values.

  Therefore, the present invention relates to a mixed fiber that can prevent the problems due to the limitations and disadvantages of the related art as described above, and a method for producing the same.

  One aspect of the present invention is to provide a mixed fiber having excellent mechanical properties while being manufactured at a relatively low cost.

  Another aspect of the present invention is to provide a method for producing a mixed fiber having excellent mechanical properties while being produced at a relatively low cost.

  Still other aspects of the invention are described below and will be apparent in part from such description. Or, other aspects of the invention may be learned through practice of the invention. Each aspect of the invention will be realized and attained by the specific structure as set forth in the detailed description of the invention and the appended claims, as well as the accompanying drawings.

  As one aspect of the present invention, in a mixed fiber, the first filament; and a second filament different from the first filament; the strength-elongation curve of the mixed fiber measured according to ASTM D 885 Has at least one peak, and when the intensity-elongation curve has two or more peaks, the first peak having the lowest elongation and the highest elongation among the two or more peaks. The mixed fiber is characterized in that the difference in elongation between the second peak and the second peak is 3% or less.

  In another aspect of the present invention, providing a first filament; preparing a second filament having a higher elongation than the first filament; and determining a difference in elongation between the first and second filaments. Applying tension to the second filament to 3% or less; and putting the first and second filaments having a difference in elongation of 3% or less to put together A method for producing a mixed fiber is provided.

  According to still another aspect of the present invention, providing a first filament; preparing a second filament having a higher elongation than the first filament; and combining the first and second filaments A method for producing a blended fiber, wherein the first filament to be combined is longer than the second filament to be combined.

  According to still another aspect of the present invention, providing a first filament; providing a second filament having a higher elongation than the first filament; the first filament at a first twist number Twisting to produce a first twisted yarn; twisting the second filament with a second twist number less than the first twist number to produce a second twisted yarn; and There is provided a method for producing a mixed fiber comprising the steps of twisting first and second twisted yarns.

  It is to be understood that both the foregoing general description and the following detailed description are only for the purpose of illustrating or describing the present invention and are intended to provide a more detailed description of the claimed invention. Must.

  According to the present invention, mixed fibers produced by mixing filaments having different properties can have new and improved properties that are completely different from the individual properties of each filament.

  Specifically, since different types of filaments are mixed after having a small difference in elongation of 3% or less, the different types of filaments constituting the mixed fiber of the present invention are both applied to the mixed fiber. As a result, the blended fibers of the present invention can have improved tensile strength and elastic modulus.

  In addition, according to the present invention, a low-priced filament can be used together with an expensive filament to produce a mixed fiber having excellent mechanical properties, so that the mixed fiber itself is manufactured using it as well as the price competitiveness. Price competitiveness of products such as tire cords, hoses, belts, cables, bulletproof clothing, ropes, composites, etc. can also be improved.

It is a graph which shows the strength-elongation curve of the mixed fiber manufactured by mixing a nylon 66 filament and an aramid filament by the conventional method. 3 is a graph showing a strength-elongation curve of a mixed fiber manufactured by mixing nylon 66 filaments and aramid filaments according to an embodiment of the present invention. 3 is a graph showing a strength-elongation curve of a mixed fiber manufactured by mixing nylon 66 filaments and aramid filaments according to an embodiment of the present invention.

  Hereinafter, the mixed fiber and the manufacturing method thereof according to examples of the present invention will be described in detail.

  It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the technical spirit and scope of the invention. Accordingly, the present invention includes all modifications and variations within the scope of the invention described in the claims and equivalents thereof.

  In the present specification, the term “mixed fiber” means a fiber manufactured by combining different types of filaments, and may be a fiber manufactured by twisting nylon filaments and aramid filaments, for example. .

  As used herein, “under twist” means twisting a filament, and “under twist” means a twisted product produced through the above-mentioned under twist.

  As used herein, “upper twist” means that two or more lower twisted yarns are twisted together, and “upper twisted yarn” means a twisted yarn produced through the upper twist.

  As used herein, “twist number” means the number of twists per meter, and its unit is TPM (Twist Per Meter).

  The mixed fiber of the present invention includes different types of filaments. According to the present invention, the different types of filaments are combined in a state having similar elongation. Therefore, the mixed fiber of the present invention has excellent tensile strength and elastic modulus.

  The blended fibers of the present invention can include aramid filaments and nylon 66 filaments.

  Aramid filaments are suitable for the manufacture of tire cords because they have low shrinkage stress and excellent creep properties. In addition, since the elastic modulus of the aramid filament is not substantially changed even at high temperatures, the risk of inducing a flat spot phenomenon is significantly reduced when the tire cord is manufactured using the aramid filament.

  However, since such an aramid filament is relatively expensive, when used as a general-purpose tire material, it may be disadvantageous from an economical viewpoint.

  Therefore, it is possible to consider a method for producing a mixed fiber by mixing nylon 66 filament, which is relatively excellent in physical properties and relatively inexpensive, with an aramid filament, and producing a tire cord using the mixed fiber. However, since the elongation difference between the aramid filament and the nylon 66 filament is large, there may be a problem that the mixed fiber produced using these filaments cannot have the tensile strength and elastic modulus corresponding to the expected values.

  More specifically, when an aramid filament having a considerable elongation difference and a nylon 66 filament are simply mixed, different filaments cannot resist the external force applied to the mixed fiber, and the elongation is low. The filament is cut after resisting first, and then the filament with high elongation is cut after resisting, resulting in a decrease in mechanical properties of the mixed fiber such as tensile strength and elastic modulus. possible. That is, one of the important causes that the mechanical properties of the mixed fiber do not reach the expected value is that different types of filaments constituting the mixed fiber individually resist external force.

  Based on the above problems and their causes, the present inventors have developed a mixed fiber having mechanical properties that satisfy the expected value and a method for producing the same.

  According to the present invention, after adjusting the elongation of different types of filaments to a similar shape, the filaments are mixed together, so that the filaments can both resist the external force applied to the mixed fibers. A mixed fiber having excellent mechanical properties can be produced.

  As a result, the mixed fiber of the present invention is advantageous in various fields because it can minimize the sacrifice of mechanical properties, which has been regarded as a disadvantage of the mixed fiber, while maintaining the unique advantage of the mixed fiber of price competitiveness. Can be used.

  In producing the mixed fiber of the present invention, various types of filaments can be used. For example, the mixed fiber is nylon filament, polyester filament, polyolefin filament, polyvinyl alcohol filament, acrylic filament, cellulose filament, urethane filament, wholly aromatic polyamide filament, wholly aromatic polyimide filament, It may include, but is not necessarily limited to, wholly aromatic polyester filaments, xylon filaments, carbon fibers, metal filaments, ore filaments, silicon filaments, glass fibers and the like.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a strength-elongation curve of a mixed fiber produced by mixing nylon 66 and aramid filaments in a conventional manner.

  As illustrated in FIG. 1, a conventional mixed fiber obtained by using a tensile tester such as Instron (manufactured by simply twisting a high elongation nylon 66 filament and a low elongation aramid filament). The strength-elongation curve has two peaks. Of the two peaks, the first peak (a) located in the low elongation region indicates the breakage of the low elongation aramid filament, and the second peak (b) located in the high elongation region is the high peak. Fig. 3 shows the breaking of a nylon 66 filament of elongation.

  As can be seen from FIG. 1, in the case of a conventional mixed fiber, the filaments can be combined while maintaining their respective elongations, so that the distance between the peaks (a, b), that is, the difference in elongation ( ΔS) becomes very large. For example, in the case of a conventional mixed fiber composed of nylon 66 filament having 20% elongation and aramid filament having 4% elongation, a difference in elongation of 10% or more is generated.

  If the difference in elongation is 3% or more, it can be considered that each filament resists the external force applied to the mixed fiber separately without synergy, and the mechanical properties of such mixed fiber satisfy the expected value. I can't let you.

  FIG. 2 shows a strength-elongation curve of a mixed fiber produced by mixing each filament with the elongation of the aramid filament and nylon 66 filament adjusted to a similar shape according to an embodiment of the present invention. .

  As illustrated in FIG. 2, the strength-elongation curve of the mixed fiber produced by mixing the filaments with the different types of filaments adjusted to have similar elongations has two peaks. It can be seen that the elongation difference is not large. That is, the elongation difference, which is the distance between the first peak (a), which is the cutting point of the aramid filament, and the second peak (b), which is the cutting point of the nylon 66 filament, is 3% or less.

  According to the present invention, the filaments are mixed in a state in which the difference in elongation between different types of filaments is reduced to 3% or less, so that the filaments resist each other to some extent against the external force applied to the mixed fibers. As a result, the mixed fiber of the present invention has excellent mechanical properties.

  FIG. 3 shows a strength-elongation curve of a mixed fiber manufactured by mixing the filaments after adjusting the elongation of the aramid filament and the nylon 66 filament to be almost the same.

  As illustrated in FIG. 3, in the case of a mixed fiber manufactured by mixing the filaments under an optimum condition in which there is no difference in elongation between different types of filaments constituting the mixed fiber, the mixed fiber is formed. Each filament resists against external forces and then cuts simultaneously. Therefore, the strength-elongation curve of such a mixed fiber has only one peak. When a strength-elongation curve having only one peak is obtained when measuring the strength and elongation of a mixed fiber, the mixed fiber resists the external force most efficiently and maximizes mechanical properties. It means having.

  In summary, the strength-elongation curve of the mixed fiber of the present invention obtained according to ASTM D 885 has at least one peak, and when the strength-elongation curve has two or more peaks, Among the two or more peaks, the difference in elongation between the first peak having the lowest elongation and the second peak having the highest elongation is 3% or less.

  Optionally, the strength-elongation curve of the blended fiber of the present invention can have only one peak. Such a mixed fiber can have more excellent mechanical properties since it can more effectively resist external force than a mixed fiber having two or more peaks in the strength-elongation curve.

  Optionally, the strength-elongation curve of the mixed fiber of the present invention has two or more peaks, and the first peak having the lowest elongation among the two or more peaks and the highest elongation. The elongation difference from the second peak is 3% or less, and the first peak may have a greater intensity than the second peak. That is, among the filaments constituting the mixed fiber, a filament having a relatively high strength has a lower elongation than a filament having a relatively low strength. Because filaments with high strength can resist external forces more effectively than filaments with low strength, it can be advantageous for filaments with high strength to have a lower elongation than filaments with low strength.

  The mixed fiber of the present invention includes first and second filaments different from each other. As described above, the mixed fiber according to an embodiment of the present invention includes an aramid filament as the first filament and a nylon 66 filament as the second filament. It can be advantageous to manufacture tire cords with aramid filaments in that aramid filaments have low shrinkage stress and the elastic modulus of aramid filaments does not change substantially at high temperatures, so that the occurrence of flat spot phenomenon can be minimized. . However, such aramid filaments are relatively expensive and can be disadvantageous from an economic point of view.

  Therefore, according to one embodiment of the present invention, nylon 66 filaments, which are relatively excellent in physical properties and relatively inexpensive, are mixed with aramid filaments to produce mixed fibers, and tire cords, hoses, belts are produced using the mixed fibers. Various products such as cables, bulletproof clothing, ropes and gloves can be manufactured.

  According to one embodiment of the present invention, the content of aramid filaments in the mixed fiber is 10 to 90% by weight. When the content of the aramid filament is less than 10% by weight, the mixed fiber cannot have mechanical properties corresponding to the expected value and cannot be applied to various fields. On the other hand, if the content of the aramid filaments exceeds 90% by weight, it is not possible to take advantage of the advantages of the mixed fiber, that is, reduction in production cost.

  The blended fiber of the present invention may be a twisted yarn. The mixed fiber in the form of a twisted yarn has an improved tensile strength because the focusing force between the filaments constituting the mixed fiber is improved.

  According to an embodiment of the present invention, the first and second filaments constituting the mixed fiber are first and second primary twisted yarns, respectively, and the mixed fiber is the first and second filaments. Ply yarn obtained through secondary twisting. For example, in the case of a mixed fiber including an aramid filament and a nylon 66 filament, each of the aramid filament and the nylon 55 filament is a lower twisted yarn twisted in the Z direction, and the mixed fiber has the lower twisted yarn in the S direction. It may be a twisted yarn produced by twisting.

  The mixed fiber in the form of the twisted yarn is not only excellent in mechanical properties, but also has a high specific surface area because the dissimilar filaments constituting it are strongly bundled. Excellent adhesion. Therefore, the mixed fiber of the present invention having such advantages can be used in various applications such as production of tire cords.

  Optionally, the first and second under-twisted yarns can have different numbers of twists. For example, a first twisted yarn manufactured by twisting aramid filaments has a twist number of 600 TPM, and a second twisted yarn manufactured by twisting nylon 66 filaments has a twist number of 200 TPM. Can do. In other words, the elongation of the first and second lower twisted yarns can be made artificially similar by varying the number of twists according to the elongation of the filaments and respectively twisting different types of filaments. The mixed fiber manufactured by twisting together the first and second lower twisted yarns having the reduced elongation difference as described above has excellent mechanical properties.

  Optionally, the blended fibers of the present invention can further comprise a resorcinol-formaldehyde-latex (RFL) adhesive. Since the mixed fiber further including such an adhesive has an excellent adhesive force to rubber, it can be used as a reinforcing material for various rubber products.

  The mixed fiber of the present invention can be used for manufacturing various products such as tire cords, hoses, belts, cables, bulletproof clothing, ropes, composites, bulletproof gloves, etc. In addition, a polyvinyl butyral resin or an ethylene vinyl acetate resin may be further included.

  Next, the manufacturing method of the mixed fiber which concerns on 1st Example of this invention is demonstrated.

  The mixed fiber manufacturing method according to the first embodiment of the present invention includes a step of preparing a first filament, a step of preparing a second filament having an elongation higher than that of the first filament, A step of applying tension to the second filament in order to make the difference in elongation between the first and second filaments 3% or less, and combining the first and second filaments in which the difference in elongation is 3% or less. Threading.

  Specifically, after each paper tube on which the first and second filaments are respectively wound is positioned on a creel, the first and second filaments are unwound from each of the paper tubes.

  Subsequently, tension is applied to the second filament in order to make the difference in elongation between the first and second filaments 3% or less. At this time, the first filament can be applied with a tension that is considerably smaller than the tension applied to the first filament, that is, a minimum tension that enables work.

  For example, the first filament may be an aramid filament having an elongation of 4% and the second filament may be a nylon 66 filament having an elongation of 20%. In order to make the elongation of the aramid filament and the nylon 66 filament the same or similar, tension is applied to the nylon 66 filament so that the nylon 66 filament is stretched by 16%. Only the minimum possible tension can be applied.

  After the tensioned second filament is combined with the first filament, the combined first and second filaments can be twisted in the Z direction to produce a twisted yarn. Then, the mixed fiber of this invention can be completed by carrying out the upper twist of the two lower twisted yarns manufactured by such a system together in the S direction. The step of combining the first and second filaments can be performed using a guide roller, can be performed using an air entanglement nozzle, and can be performed using an adhesive, but is not necessarily limited thereto. It will never be done. Since the required fineness of the mixed fiber varies depending on the application, the number of the respective lower twisted yarns can be adjusted in consideration of this.

  Optionally, the first and second filaments are respectively twisted in the Z direction before the tensioned second filaments are combined with the first filaments to produce the respective lower twisted yarns, The twisting process can be performed by twisting the lower twisted yarn together in the S direction.

  Next, the manufacturing method of the mixed fiber which concerns on the 2nd Example of this invention is demonstrated.

  The mixed fiber manufacturing method according to the second embodiment of the present invention includes a step of preparing a first filament, a step of preparing a second filament having an elongation higher than that of the first filament, Combining the first and second filaments.

  According to a second embodiment of the present invention, when the first and second filaments are combined, the first filament to be combined is longer than the second filament to be combined. The first filament is supplied more than the second filament.

  For example, the first filament may be an aramid filament having an elongation of 4% and the second filament may be a nylon 66 filament having an elongation of 20%. Further, the aramid filament can be over-supplied so that the aramid filament to be combined is 15% longer than the nylon 66 filament to be combined.

  Optionally, the method may further include applying tension to the second filament before combining the first and second filaments. That is, in the above example, tension is applied to the nylon 66 filament so as to stretch the nylon 66 filament by 5%, and the aramid filament to be combined is 10% longer than the nylon 66 filament to which the tension is applied. Thus, the aramid filament can be oversupplied.

  After the longer first filament is combined with the second filament, the combined first and second filaments are twisted in the Z direction to produce a lower twisted yarn. Subsequently, the mixed fiber of the present invention can be completed by twisting together a plurality of lower twisted yarns manufactured in this manner in the S direction. Since the required fineness of the mixed fiber varies depending on the application, the number of the respective lower twisted yarns can be adjusted in consideration of this.

  Optionally, before combining the longer first filament with the second filament, the first and second filaments are respectively twisted in the Z direction to produce each twisted yarn, It is also possible to carry out the above-described yarn blending process by twisting together in the S direction.

  Next, the manufacturing method of the mixed fiber which concerns on the 3rd Example of this invention is demonstrated.

  The mixed fiber manufacturing method according to the third embodiment of the present invention includes a step of preparing a first filament, a step of preparing a second filament having higher elongation than the first filament, First twisting one filament with a first twist number to produce a first twisted yarn, and twisting the second filament with a second twist number smaller than the first twist number, Two twisted yarns and twisting the first and second twisted yarns.

  For example, the first filament may be an aramid filament having an elongation of 4% and the second filament may be a nylon 66 filament having an elongation of 20%. The first twisted yarn manufactured by twisting aramid filaments has a twist number of 600 TPM, and the second twisted yarn manufactured by twisting nylon 66 filaments has a twist number of 200 TPM. Can do.

  According to the third embodiment of the present invention, the number of twists is varied according to the elongation of the filaments, and the first and second lower twisted yarns are artificially deformed by respectively twisting different types of filaments. The mixed fiber manufactured by twisting together the first and second lower twisted yarns having a reduced elongation difference as described above may have excellent mechanical properties. become.

  Optionally, when producing the second lower twisted yarn, the second filament can be twisted while applying tension to the second filament. That is, in the above example, the aramid filaments can be twisted in an unstretched state while the nylon 66 filaments can be twisted in a stretched state of 15%.

  The manufacturing method of the mixed fiber of this invention can further include the following process.

  A resorcinol-formaldehyde-latex (RFL) adhesive may be applied to the first and second filaments combined by any one of the first to third embodiments of the present invention described above.

  The step of applying the RFL adhesive can be performed by various methods. For example, the adhesive is applied to the combined first and second filaments through a dipping process in which the combined first and second filaments are immersed in a resorcinol-formaldehyde-latex (RFL) adhesive solution. can do. At this time, 1-bath dipping or 2-bath dipping can be used. The RFL adhesive solution was 2.0% by weight resorcinol, 3.2% by weight formalin (37%), 1.1% by weight sodium hydroxide (10%), 43.9% by weight styrene / butadiene. / Vinylpyridine (15/70/15) rubber (41%), and water.

  After the adhesive is applied to the combined first and second filaments, a heat treatment step can be performed. For the heat treatment, a first heat treatment step that proceeds at 105 to 200 ° C. for 10 to 400 seconds and a second heat treatment step that proceeds at 105 to 300 ° C. for 10 to 400 seconds can be sequentially performed.

  The mixed fiber of the present invention produced as described above can be used in various fields such as tire cords, hoses, belts, cables, bulletproof clothing, ropes, composites, and bulletproof gloves.

  Hereinafter, the present invention will be described in detail through examples and comparative examples. However, each of the following examples is only for facilitating the understanding of the present invention, and the scope of rights of the present invention should not be limited thereby.

Example 1

  Nylon 66 filament having a tensile strength of 9 g / d, an elongation of 20% and a fineness of 1,000 denier and a paraffin having a tensile strength of 23 g / d, an elongation of 4% and a fineness of 1,000 denier A series aromatic polyamide filament was combined. At this time, the nylon 66 filament was combined with a para-aromatic polyamide filament in a stretched state of 16%. The para-type aromatic polyamide filament was combined with the nylon 66 filament in an unstretched state.

  Subsequently, the above twisted filaments were twisted in the Z direction at a twist number of 285 TPM using an Alma Co. ring type twisting machine (Ring type twister) to produce a lower twisted yarn.

  Subsequently, a mixed fiber was produced by twisting the two lower twisted yarns in the S direction with a twist number of 300 TPM. The content of the para-aromatic polyamide filament in the mixed fiber was 50%.

Examples 2 and 3

  A mixed fiber was produced by the same method as in Example 1 except that the nylon 66 filament was combined with a para-aromatic polyamide filament in a state where the nylon 66 filament was stretched at 15% and 17%, respectively.

Example 4

  Nylon 66 filament having a tensile strength of 9 g / d, an elongation of 20% and a fineness of 1,000 denier and a paraffin having a tensile strength of 23 g / d, an elongation of 4% and a fineness of 1,000 denier A series aromatic polyamide filament was combined. At this time, the para-type aromatic polyamide filament was over-supplied so that the para-type aromatic polyamide filament to be combined was 15% longer than the nylon 66 filament to be combined.

  Subsequently, a lower twisted yarn was produced by twisting each of the combined filaments in the Z direction with a twist number of 285 TPM using an Alma ring type twisting machine.

  Subsequently, a mixed fiber was produced by twisting the two lower twisted yarns in the S direction with a twist number of 300 TPM.

Example 5

  Nylon 66 filament having a tensile strength of 9 g / d, an elongation of 20%, and a fineness of 2,000 denier is stretched 15%, and then the stretched nylon 66 is stretched using an Alma ring type twisting machine. Nylon 66 bottom twisted yarn was produced by twisting the filament in the Z direction with a twist number of 200 TPM.

  In addition, a para-aromatic polyamide filament having a tensile strength of 23 g / d, an elongation of 4%, and a fineness of 2,000 denier was twisted in the Z direction at a twist number of 400 TPM using a ring type twisting machine manufactured by ALMA. Thus, a para-aromatic polyamide lower twisted yarn was produced.

  Subsequently, a mixed fiber was produced by twisting the nylon 66 lower twisted yarn and the para-aromatic polyamide lower twisted yarn in the S direction at a twist number of 300 TPM.

Examples 6 and 7

  Example 1 except that the fineness of the nylon 66 filament and the para-aromatic polyamide filament was adjusted so that the content of the para-aromatic polyamide filament in the mixed fiber was 10 and 90% by weight, respectively. A mixed fiber was produced by the same method.

Comparative Example 1

  A mixed fiber was produced in the same manner as in Example 1, except that the nylon 66 filament was combined with a para-aromatic polyamide filament in an unstretched state.

Comparative Example 2

  A mixed fiber was produced in the same manner as in Example 1, except that the nylon 66 filament was combined with the para-aromatic polyamide filament in a state of being stretched 2%.

  The tensile strength, elongation, and elongation difference of each mixed fiber obtained in each of the above Examples and Comparative Examples were determined by the following methods, and the results are shown in Table 1.

Tensile strength (g / d) and elongation (%) of mixed fiber

  ASTM D 885 test method was used at 300 m / min for a sample length of 250 mm at 25 ° C. and 65% relative humidity using an Instron tester (Instron Engineering Corp., Canton, Mass). The tensile strength and elongation of the mixed fiber were measured by applying speed.

Difference in elongation (ΔS)

  In the strength-elongation curve of the mixed fiber obtained when the tensile strength and elongation of the mixed fiber are measured by the method described above, the elongation at the first peak (a ′) and the elongation at the second peak The elongation difference (ΔS) of the mixed fiber was measured using the degree (b ′).

Claims (20)

In mixed fiber,
A first filament; and a second filament different from the first filament;
The mixed fiber strength-elongation curve measured according to ASTM D 885 has at least one peak;
When the intensity-elongation curve has two or more peaks, the elongation between the first peak having the lowest elongation and the second peak having the highest elongation among the two or more peaks. A mixed fiber having a degree difference of 3% or less.   The mixed fiber according to claim 1, wherein the strength-elongation curve has one peak. The strength-elongation curve has two or more peaks,
The mixed fiber according to claim 1, wherein the first peak has a greater intensity than the second peak. The first filament is an aramid filament,
The second filament is a nylon 66 filament,
The mixed fiber according to claim 1, wherein the content of the aramid filament in the mixed fiber is 10 to 90% by weight.   The mixed fiber according to claim 1, wherein the mixed fiber is a twisted product. The first filament is a first twisted yarn;
The second filament is a second twisted yarn;
The mixed fiber according to claim 1, wherein the mixed fiber is a twisted yarn obtained through an upper twist of the first and second twisted yarns.   The mixed fiber according to claim 6, wherein the first and second twisted yarns have different numbers of twists.   The mixed fiber according to claim 1, further comprising a resorcinol-formaldehyde-latex adhesive. Providing a first filament;
Providing a second filament having a higher elongation than the first filament;
Applying tension to the second filament to reduce the difference in elongation between the first and second filaments to 3% or less; and the first and second filaments having a difference in elongation of 3% or less. A method for producing a mixed fiber, comprising the step of: Further comprising applying tension to the first filament;
The method for producing a mixed fiber according to claim 9, wherein a tension applied to the first filament is smaller than a tension applied to the second filament. The first filament is an aramid filament,
The method for producing a mixed fiber according to claim 9, wherein the second filament is a nylon 66 filament. Before the first and second filaments are combined, further comprising the step of twisting the first and second filaments to produce each of the lower twisted yarns,
The method for producing a mixed fiber according to claim 9, wherein the combined yarn is performed by twisting each of the lower twisted yarns. 10. The method according to claim 9, further comprising: twisting the combined first and second filaments to produce each lower twist yarn; and twisting each lower twist yarn. The manufacturing method of the mixed fiber of description. Providing a first filament;
Providing a second filament having a higher elongation than the first filament; and combining the first and second filaments;
The method for producing a mixed fiber, wherein the first filament to be combined is longer than the second filament to be combined.   The method for producing a mixed fiber according to claim 14, wherein the first filament to be combined is longer than the second filament to be combined.   The mixed fiber manufacturing method according to claim 14, further comprising a step of applying tension to the second filament before the first and second filaments are combined. Before the first and second filaments are combined, further comprising the step of twisting the first and second filaments to produce each of the lower twisted yarns,
The method for producing a mixed fiber according to claim 14, wherein the combined yarn is performed by twisting each of the lower twisted yarns. 15. The method according to claim 14, further comprising: twisting the combined first and second filaments to produce each bottom twist yarn; and twisting each bottom twist yarn. The manufacturing method of the mixed fiber of description. Providing a first filament;
Providing a second filament having a higher elongation than the first filament;
Twisting the first filament with a first twist to produce a first twisted yarn;
Twisting the second filament with a second twist number smaller than the first twist number to produce a second twisted yarn; and twisting the first and second twisted yarns; The manufacturing method of the mixed fiber characterized by including.   The method for producing a mixed fiber according to claim 19, wherein the second filament yarn is produced by twisting the second filament while applying tension to the second filament.

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