JP6294655B2 - Method for connecting fiber yarn and method for producing carbon fiber - Google Patents

Description

  The present invention relates to a method for connecting fiber yarns in which connected fiber yarns and connecting fiber yarns are entangled and connected, and a method for producing carbon fibers using this fiber yarn connecting method.

  Carbon fiber has features such as high tensile strength, high tensile modulus, excellent heat resistance and fatigue properties, and is widely used in fields such as sports, leisure, aviation, and space.

  Carbon fiber is made into flame-resistant fiber by heating raw fiber such as acrylic fiber to 200-300 ° C in air, and then fired at 1000 ° C or higher in an inert atmosphere using a carbonization furnace. Manufactured. In general, raw material fibers are contained in packages such as bobbins and bags. When continuous production is performed, the end of the fiber yarn supplied to the production process and the package are switched at the time of switching the package. It is necessary to connect the start end of the accommodated fiber yarn.

  As a means for connecting fiber yarns, an apparatus and a method for sandwiching two fiber yarns and interlacing them with a pressurized fluid are disclosed (Patent Document 1). By this method, the entangled point shape of the fiber yarn can be uniformly formed, but the entangled part formed has an increased fiber bundle density, and therefore the entangled part excessively stores heat due to the heat generation of the fiber itself in the flameproofing process. However, there is a problem that the fiber is cut.

  Patent Document 2 discloses a method for connecting fiber yarns in which two connected fiber yarns are connected via connecting fiber yarns. In this connection method, the entanglement point has a structure having a plurality of partial entanglement points in one entanglement point, and the entangled part can be efficiently removed of heat. Also in this connection method, the connected fiber yarn and the connecting fiber yarn are fluid entangled in a state where both yarns are overlapped. However, when two overlapped yarns are entangled, the connected fiber yarn or the connected fiber yarn is connected. Since some of the fiber yarns may form entanglement points independently, the fiber dispersibility and uniformity of the entanglement points may not be sufficient. As a result, the connection strength may not be sufficient because the connection portion may come off during the manufacturing process, or the connected fiber yarn may partially store heat during the flame resistance and the connection portion may be cut off.

JP-A-6-206667 JP 2010-255168 A

  An object of the present invention is to provide a method for connecting fiber yarns that suppresses cutting due to heat storage at the connection portion of the fiber yarns and has high connection strength. Furthermore, it is providing the manufacturing method of carbon fiber using the connection method of this fiber yarn.

  The inventor has intensively studied to achieve the above object. As a result, the connecting fiber yarns and the connected fiber yarns are mixed in units of single yarns before being entangled, thereby suppressing the fiber yarns from being cut due to heat storage at the connecting portion, and the fibers having high connection strength. The present inventors have found that yarns can be connected and have completed the present invention.

  The present invention for achieving the above object is described below.

[1] A method for connecting fiber yarns, in which two connected fiber yarns are connected via connecting fiber yarns,
By connecting and overlapping the connected fiber yarns and the connecting fiber yarns, an overlapping portion of the connected fiber yarns and the connecting fiber yarns is formed,
After sandwiching the overlapped portion and injecting fluid to the overlapped portion to form a preliminary entangled portion,
A method for connecting fiber yarns, wherein a fluid is injected into the preliminary entangled portion to form a main entangled portion in the preliminary entangled portion.

  That is, a method for connecting fiber yarns, in which a connected fiber yarn and a connecting fiber yarn are mixed in a restrained state to form a preliminary entangled portion, and then the preliminary entangled portion is further entangled in an unconstrained state. It is. The present invention includes the following [2]-[7].

  [2] The method for connecting fiber yarns according to [1], wherein the connecting fiber yarns have 1-4 times as many filaments as the connected fiber yarns.

  [3] The preliminary entangled portion sandwiches the overlapping portion so that the relaxation rate of the connecting fiber yarn and the connecting yarn in the overlapping portion is 0.03 to 2%, respectively. [1] The fiber yarn connecting method according to [1].

  [4] The fiber yarn connecting method according to [1], wherein the main entanglement is formed by injecting a fluid to the preliminary entangled portion so that a length shrinkage rate is 1 to 40%.

  [5] The fiber yarn connecting method according to [1], wherein the number of filaments of the connected fiber yarn is 3000 to 50000.

  [6] The method for connecting fiber yarns according to [1], wherein the connected fiber yarns are made of acrylic fibers, and the connecting fiber yarns are made of flameproof fibers.

  [7] A method for producing carbon fiber, comprising a step of connecting fiber yarns by the fiber yarn connection method according to [1]-[6].

  In the fiber yarns connected by the connection method of the present invention, the connecting fiber yarns and the connected fiber yarns are mixed in advance in single yarn units. Therefore, the frictional force between the fiber yarns is increased at the connection portion between the connecting fiber yarns and the connected fiber yarns. As a result, the connection strength between the connecting fiber yarn and the connected fiber yarn is high.

  In addition, since the connecting fiber yarns and the connected fiber yarns exist without being unevenly distributed in the connecting portion, heat storage in the connecting portion is suppressed. As a result, the fiber yarn is hardly cut due to heat storage at the connection portion between the connecting fiber yarn and the connected fiber yarn.

1a to 1c are explanatory views conceptually showing the entangled state of fiber yarns connected by the fiber yarn connecting method of the present invention. 2a-2b are explanatory views showing one configuration example of an apparatus used in the fiber yarn connecting method of the present invention. FIG. 3 is an explanatory view showing a connection configuration example of the fiber yarn of the present invention.

  Hereinafter, the fiber yarn connecting method of the present invention will be described with reference to the drawings.

  1a to 1c are explanatory views conceptually showing the entangled state of fiber yarns connected by the fiber yarn connecting method of the present invention. In FIG. 1, reference numeral 11 denotes a connected fiber yarn, and 11a denotes a filament yarn of the connected fiber yarn. Reference numeral 15 denotes a connecting fiber yarn, and reference numeral 15a denotes a filament yarn of the connecting fiber yarn.

  First, the connected fiber yarns 11 and the connecting fiber yarns 15 are aligned and overlapped to form an overlapping portion (FIG. 1a). Next, both ends of the overlapping portion of the connected fiber yarn 11 and the connecting fiber yarn 15 are clamped (hereinafter, the connected fiber yarn and the connecting fiber yarn are clamped by a clamping mechanism (described later). Is also referred to as “clamping point”). It is preferable that the connected fiber yarns and the connecting fiber yarns in the overlapping portion are sandwiched so that the relaxation rate is 0.03 to 2%. Thereafter, when the fluid is sprayed onto the connected fiber yarns 11 and the connected fiber yarns 15 at the overlapping portions between the holding points, the connected fiber yarns 11 and the connecting fiber yarns 15 at the overlapping portions between the holding points are used. Are both open. After the ejection of the fluid is finished, the opened connected fiber yarns 11 and the connected fiber yarns 15 converge without being able to completely return the respective filament yarns to their original positions. Thus, the pre-entangled portion 12 having a length La mixed with the filament yarns 11a and 15a (single yarn unit) is formed (FIG. 1b).

Where the relaxation rate is
Relaxation rate (%) = [(actual length of fibers clamped between clamping points) − (linear distance between clamping points)] / [linear distance between clamping points] × 100
Defined by

  Next, the holding of the pre-entangled portion 12 is released, and fluid is ejected here. The fiber yarn in the pre-entangled state turns and is strongly twisted, and the main entangled portion 13 having lengths Lb1 and Lb2 is formed in the pre-entangled portion 12 (FIG. 1c). At this time, it is preferable that the entangled portion is formed so that the length shrinkage rate is 1 to 40%.

Where the length shrinkage is
Length shrinkage rate (%) = [(length of pre-entangled portion 12 before main entanglement) − (total length of main entangled portion 13 formed in preliminary entangled portion 12 + length of remaining remaining pre-entangled portion 12) ]] / [Total length of the entangled portion 13] × 100
Defined by

  That is, in FIG. 1C, the length shrinkage is [La− (Lb1 + Lb2 + La1 + La2 + La3)] / [Lb1 + Lb2] × 100.

  2a-2b are explanatory views showing one configuration example of an apparatus used in the fiber yarn connecting method of the present invention. In FIG. 2 a, 11 is a connected fiber yarn, 15 is a connecting fiber yarn, and 25 is an entanglement device. The entanglement device 25 includes an entanglement means 29 capable of reciprocating in the fiber yarn direction, and clamping mechanisms 21 and 23 for the connected fiber yarns 11 and the connection fiber yarns 15. For the connection of the fiber yarns, one entanglement device 25 or a plurality of the entanglement devices 25 can be used in parallel. The entanglement means 29 is connected to a fluid supply source (not shown), and an arrow 29a indicates the flow direction of the fluid. FIG. 2 b shows a state where the connected fiber yarns 11 and the connecting fiber yarns 15 are clamped using the clamping mechanisms 21 and 23.

  One end side of the to-be-connected fiber yarn 11 and one end side of the connecting fiber yarn 15 are overlapped with a predetermined length and passed through the entanglement device 25 (FIG. 2a). Next, the connected fiber yarns 11 and the connecting fiber yarns 15 are clamped by using the clamping mechanisms 21 and 23, and the overlapping portion that is clamped by the clamping mechanisms 21 and 23 between the clamping mechanisms 21 and 23. Is formed (FIG. 2b). At this time, it is preferable that the to-be-connected fiber yarns 11 and the connecting fiber yarns 15 are pinched so that the relaxation rate between the pinching points is 0.03 to 2%.

  The adjustment method of the relaxation rate may be adjusted by directly measuring the actual lengths of the connected fiber yarns and the connected fiber yarns, and pinching each fiber yarn at a predetermined actual length. After the fiber yarns and the connecting fiber yarns are held in a slack-free state, adjustment may be made by moving the holding point in the fiber length direction.

  Thereafter, in this state, the high-pressure fluid is ejected toward the connected fiber yarn 11 and the connecting fiber yarn 15 by the entanglement means 29 that can reciprocate along the fiber yarn. As a result, the connected fiber yarns 11 and the connecting fiber yarns 15 are mixed in units of the respective filament yarns 11a and 15a to form the preliminary entangled portion 12 (FIG. 1b).

  Next, the clamping of the connected fiber yarn 11 and the connecting fiber yarn 15 by the clamping mechanisms 21 and 23 is released. As a result, the constrained fiber yarns 11 and the connecting fiber yarns 15 in the preliminary entangled portion 12 are released from the untangled state. In this state, high-pressure fluid is ejected from the entanglement means 29 toward the preliminary entanglement portion 12. Thereby, the main entangled part 13 is formed in the preliminary entangled part 12, and the to-be-connected fiber yarn 11 and the connecting fiber yarn 15 are connected.

  In FIG. 2 a and FIG. 2 b, one entanglement means 29 is shown in the entanglement device 25, but a plurality of entanglement means 29 may be provided in the entanglement device 25. As the entanglement means 29, known means such as an interlace nozzle can be used.

  In the present invention, the preliminary entanglement means that the connected fiber yarns and the connecting fiber yarns are overlapped and sandwiched to be in a restrained state, and a high-pressure fluid is jetted onto them to thereby connect the connected fiber yarns and the connecting fiber yarns. This means that the filaments are mixed in single yarn units. Since it is carried out in a state where the mixed fibers of the connected fiber yarns and the connecting fiber yarns are restrained, both the fiber yarns do not substantially turn. Therefore, a twist is not substantially formed in both fiber yarns.

  The preliminary entanglement may be performed with the positions of the plurality of entanglement means being fixed, or may be performed while reciprocating one or more entanglement means in the fiber yarn direction.

  In the restrained state, both ends of the connected fiber yarn and the connecting fiber yarn are preferably sandwiched at a relaxation rate of 0.03 to 2%, and more preferably 0.1 to 1%. . When the relaxation rate is less than 0.03%, it is difficult to form the preliminary entangled portion. Further, the fiber yarn is easily damaged by the high-pressure fluid. When the relaxation rate exceeds 2%, a twist is easily formed and a preliminary entangled portion is hardly formed. When the connected fiber yarns and the connecting fiber yarns of the pre-entangled part are not mixed in units of single yarns, a location where the connected fiber yarns are unevenly distributed may be formed at the connecting portion. In this case, the fiber yarn is easily cut by heat storage.

  The preliminary entangled portion may be formed over the entire overlapping portion of the connected fiber yarn and the connecting fiber yarn, or may be formed in part.

  The length of the preliminary entangled portion is preferably 90-2000 mm, and more preferably 140-1000 mm. When the thickness is less than 90 mm, the effect of increasing the strength by mixing fiber yarns may not be sufficiently obtained. When it exceeds 2000 mm, the apparatus equipment for entanglement becomes large, and it becomes economically disadvantageous.

  In the present invention, the term “entanglement” refers to entanglement of the fiber yarn of the preliminary entangled portion by turning or the like by injecting a high-pressure fluid thereto in a state where the constraint of the preliminary entangled portion is released. Since this entanglement is performed in an unconstrained state, the fiber yarns of the preliminary entanglement part are turned by the injection of high pressure fluid. As a result, a twist is formed in the preliminary entangled portion.

  This entanglement may be performed in a state where the positions of the plurality of entanglement means are fixed, or may be performed while reciprocating one or more entanglement means in the fiber yarn direction. In addition, the preliminary entanglement means and the main entanglement means may use the same means, or separate dedicated means may be used.

  The length of the entangled portion is preferably 15 mm or more, and more preferably 20 mm or more. And it is preferable that the length of the main entangled portion per place does not exceed the length of the pre-entangled portion per place. Furthermore, it is more preferable that the preliminary entangled portions remain at least 10 mm on both ends of the entangled portion. When the length of the main entangled portion is less than 15 mm, or when the length of the main entangled portion exceeds the length of one portion of the preliminary entangled portion, the connection strength may be insufficient.

  The degree of entanglement of this entanglement is represented by the above-mentioned length shrinkage rate. The length shrinkage is preferably 1-40% and more preferably 3-33%. If it is less than 1%, the twist is insufficient and the connection strength tends to be insufficient. When it exceeds 40%, the connecting portion is tightly tightened, the fiber bundle density becomes excessive, and heat storage cutting is likely to occur.

  The fiber yarn connecting method of the present invention is preferably used when two connected fiber yarns are connected via a connecting fiber yarn therebetween.

  FIG. 3 is an explanatory view showing an aspect in which two connected fiber yarns 31 and 33 are connected via connecting fibers 35. Hereinafter, 31 will be described as the first fiber yarn, 33 as the second fiber yarn, and 35 as the third fiber yarn.

  The first fiber yarn 31 and the second fiber yarn 33 are the same type of fiber yarn. The first fiber yarn 31 and the second fiber yarn 33 are connected via a third fiber yarn 35. That is, one end side of the third fiber yarn 35 is connected to the side end portion of the first fiber yarn 31, and the other end side of the third fiber yarn 35 is connected to the side end portion of the second fiber yarn 33. Thus, the first fiber yarn 31 and the second fiber yarn 33 are indirectly connected via the third fiber yarn 35. When connected in this way, the first fiber yarn 31 and the second fiber yarn 33 are not directly connected. Thereby, it can avoid that the part which the 1st fiber yarn 31 and the 2nd fiber yarn 33 overlap is formed. Therefore, it is possible to avoid heat storage of the fiber yarns due to the same type of fiber yarns concentrating on the connecting portion. The connection between the first fiber yarn 31 and the third fiber yarn 35 and the connection between the second fiber yarn and the third fiber yarn are the above-mentioned connection method between the connected fiber yarn and the connection fiber yarn. Since this is the same, the description thereof is omitted.

  As for the 1st fiber yarn 31 and the 2nd fiber yarn 33, it is preferred that each filament number is 3000-50000, and it is more preferred that it is 6000-30000. The number of filaments of the third fiber yarn 35 is preferably 3000-200000, and more preferably 6000-120000.

  The number of filaments of the third fiber yarn 35 is preferably 1-4 times the number of filaments of the first fiber yarn 31 and the second fiber yarn 33, more preferably 1-2 times. . When it is less than 1 time, heat accumulation is likely to occur in the fiber yarn at the connecting portion, and the fiber yarn may be cut. When it exceeds 4 times, the entanglement may become insufficient and the connection strength may decrease.

The fiber yarn connecting method of the present invention is particularly preferably employed in the carbon fiber manufacturing process. Generally, carbon fiber is made into flame-resistant fiber by heating raw fiber such as acrylic fiber to 200-300 ° C. in the air, and then this flame-resistant fiber is 1000 ° C. in an inert atmosphere using a carbonization furnace. It is manufactured by baking as described above. When the method for connecting fiber yarns of the present invention is used in the production of carbon fibers, the first fiber yarns 31 and the second fiber yarns 33 are acrylic fibers, and the third fiber yarns 35 are acrylic fibers that are flame resistant. This is a flameproof fiber. Density of oxidized fiber is preferably 1.35-1.45g / cm ^3, more preferably 1.36-1.43g / cm ^3. When it is less than 1.35 g / cm ³ , the fiber yarn at the connection portion is likely to be cut by heat accumulation in the flameproofing step. When exceeding 1.45 g / cm < ³ >, it is unpreferable mainly from a viewpoint of economical efficiency.

  The acrylic fiber generates heat due to a chemical reaction during the flameproofing treatment, but the flameproofed fiber hardly generates heat during the flameproofing treatment. Therefore, by connecting the two acrylic fiber yarns via the flame-resistant fiber yarn, it is possible to avoid heat accumulation due to concentration of heat-generating fibers (acrylic fibers) at the connection portion of the fiber yarns. it can.

  Examples of the high-pressure fluid applied to the entanglement means 29 include compressed air, various compressed gases such as inert gas, and various fluids such as water. As described above, the entanglement means may be used with the position fixed, or may be used while reciprocating in the fiber yarn direction. Moreover, you may use together a fixed type and a moving type confounding means.

  The pressure of the fluid sprayed onto the fiber yarn is preferably 0.2 to 0.8 MPa, more preferably 0.3 to 0.7 MPa. When the pressure is less than 0.2 MPa, the mixed fiber and the main entanglement tend to be insufficient. When it exceeds 0.8 MPa, the fiber yarn other than the entangled portion is likely to be disturbed, and the fiber yarn is easily damaged.

  When the mobile entanglement means is used, the high-pressure fluid injection time onto the fiber yarn is preferably 3-90 seconds, and more preferably 5-60 seconds. When using a fixed entanglement means, 1-30 seconds is preferable, and 2-20 seconds is more preferable. When the injection time is short, confounding tends to be insufficient. When the injection time is long, it is not preferable mainly from the viewpoint of economy.

  When using a mobile entanglement means, the moving speed is preferably 1-200 mm / second, more preferably 5-60 mm / second. When it is less than 1 mm / second, it is not preferable mainly from the viewpoint of economy. When it exceeds 200 mm / sec, preliminary entanglement or main entanglement tends to be insufficient.

  When using a mobile entanglement means, the moving distance is preferably 90-2000 mm, and more preferably 140-1000 mm / sec. As described above, when the length of the preliminary entangled portion is less than 90 mm, the effect of increasing the strength by mixing the fiber yarns may not be sufficiently obtained. When it exceeds 2000 mm, handling of the fibers becomes difficult and an economically disadvantageous situation such as an increase in the size of the apparatus is brought about.

  When the mobile entanglement means is used, one entanglement means may be used, or a plurality of entanglement means separated from each other by 50 mm or more and 1000 mm or less may be used.

  When the mobile entanglement means is used to form the preliminary entanglement portion, the number of reciprocations of the entanglement means is preferably 1-10 reciprocations, and more preferably 2-5 reciprocations. If it is less than one round trip, the fiber mixture tends to be insufficient. When it exceeds 10 reciprocations, fluff is likely to occur on the fiber yarn. The generated fluff causes troubles during this entanglement and manufacturing process troubles after the completion of this entanglement.

  When the mobile entanglement means is used for forming the entanglement portion, the reciprocation number of the entanglement means is preferably 0.5-3 reciprocation, and more preferably 1-2 reciprocation. If it is less than 0.5 round trips, this confounding tends to be insufficient. When it exceeds 3 reciprocations, fluff is likely to occur on the fiber yarn. The resulting fluff causes trouble in subsequent manufacturing processes. The present entangled portion may be formed while moving the entangled means within the range of the length where the preliminary entangled portion exists. There is no particular limitation on the number of entangled portions, but a smaller number is more economical.

  When using a fixed type of entanglement means, it is preferable to form 2 to 10 and more preferably 3 to 8 entangled portions per connection. When the number is less than two, the connection strength of the fiber yarn tends to be insufficient. When the number exceeds 10, it is not preferable mainly from the viewpoint of economy.

  The distance between the main entanglement points (referring to the distance between the center points of the adjacent main entanglement parts) is preferably 50 to 1000 mm. When it is less than 50 mm, adjacent main entangled portions may interfere with each other to cause a problem in the main entangled state. When exceeding 1000 mm, it is unpreferable mainly from an economical viewpoint.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to an Example. In this example and a comparative example, the process pass rate refers to the ratio that has passed through the final process without the connection part being cut off during the manufacturing process.

Example 1
An acrylic fiber yarn having 24,000 filaments was used as the connected fiber, and a flame-resistant fiber yarn having 24,000 filaments was used as the connecting fiber. The connected fibers and the connecting fibers are aligned and overlapped by the apparatus having the structure shown in FIG. 2, and the connected fibers and the connecting fibers are sandwiched by the apparatus having the structure shown in FIG. The relaxation rate at this time was 0.3%.
While the two movable nozzles separated by 200 mm are reciprocated twice over 30 seconds to the overlapping portion, compressed air (pressure 0.4 MPa) is sprayed onto the overlapping portion to connect the connected fiber and the connecting fiber. A 400 mm pre-entangled part was formed by mixing.
After that, the clamping between the connected fiber and the connecting fiber was released. Two moving nozzles were used for the preliminary entangled portion, and compressed air (pressure 0.4 MPa) was sprayed for 5 seconds each at four locations of the preliminary entangled portion to form four main entangled portions in the preliminary entangled portion. The length shrinkage was 20%. The process pass rate of the fiber yarns connected by this connection method was 100% in the flameproofing process and 100% in the carbonization process.

(Example 2)
An acrylic fiber yarn having 24,000 filaments was used as the connected fiber, and a flame-resistant fiber yarn having 24,000 filaments was used as the connecting fiber. The connected fiber and the connecting fiber were overlapped by the apparatus having the structure shown in FIG. 2, and the connected fiber and the connecting fiber were sandwiched by the apparatus having the structure shown in FIG. The relaxation rate at this time was 0.3%.
In this overlapped portion, four fixed nozzles separated by 100 mm are used to inject compressed air (pressure 0.4 MPa) into the overlapped portion for 10 seconds to mix the fibers to be connected and the connecting fibers to obtain 400 mm. The preliminary entanglement part was formed.
After that, the clamping between the connected fiber and the connecting fiber was released. Four fixed nozzles were used for the preliminary entangled portion, and compressed air (pressure 0.4 MPa) was sprayed to four locations of the preliminary entangled portion for 5 seconds, respectively, thereby forming four main entangled portions in the preliminary entangled portion. The length shrinkage was 20%. The process pass rate of the fiber yarns connected by this connection method was 100% in the flameproofing process and 100% in the carbonization process.

(Example 3)
The connection was made in the same manner as in Example 1 except that the relaxation rate of the connected fiber yarn and the connecting fiber yarn at the time of preliminary entanglement was changed as shown in Table 1. The process pass rate was as shown in Table 1.

Example 4
The connection was made in the same manner as in Example 1 except that the compressed air pressure at the time of forming the four entanglements in the preliminary entanglement portion was 0.2 MPa and the length shrinkage rate at the time of the main entanglement was changed as described in Table 1. . The process pass rate was as shown in Table 1.

(Examples 5, 6, 7, 8)
The connection was made in the same manner as in Example 1 except that the number of filaments of the connected fiber yarn and the connecting fiber yarn was changed as shown in Table 1. The process pass rate was as shown in Table 1.

Example 9
An acrylic fiber yarn having 24,000 filaments was used as the connected fiber, and a flame-resistant fiber yarn having 24,000 filaments was used as the connecting fiber. The connected fibers and the connecting fibers are aligned and overlapped by the apparatus having the structure shown in FIG. 2, and the connected fibers and the connecting fibers are sandwiched by the apparatus having the structure shown in FIG. The relaxation rate at this time was 0.3%.
A single movable nozzle is reciprocated twice over 60 seconds in this overlapping portion, and compressed air (pressure 0.4 MPa) is sprayed onto the overlapping portion to mix the connected fibers and the connecting fibers. A 400 mm pre-entangled part was formed.
After that, the clamping between the connected fiber and the connecting fiber was released. One moving nozzle was used for the preliminary entangled portion, and compressed air (pressure 0.4 MPa) was sprayed for 5 seconds to each of the five locations of the preliminary entangled portion to form five main entangled portions in the preliminary entangled portion. The length shrinkage was 20%. The process pass rate of the fiber yarns connected by this connection method was 100% in the flameproofing process and 100% in the carbonization process.

(Example 10)
Connection was made in the same manner as in Example 9 except that the preliminary entanglement time was 42 seconds, the preliminary entanglement length was 280 mm, the preliminary entanglement part was formed, and three main entanglements were formed in the preliminary entanglement part. The process pass rate was as shown in Table 1.

(Example 11)
The connection was made in the same manner as in Example 10 except that the preliminary entanglement part was formed with the preliminary entanglement time being 150 seconds and the preliminary entanglement length being 1000 mm. The process pass rate was as shown in Table 1.

(Comparative Example 1)
The connection was made in the same manner as in Example 1 except that no pre-entangled part was formed. The process pass rate was as shown in Table 1.

(Comparative Example 2)
The connection was made in the same manner as in Example 1 except that the relaxation rate of the connected fiber yarn and the connecting fiber yarn at the time of preliminary entanglement was changed as shown in Table 1. The process pass rate was as shown in Table 1.

(Comparative Example 3)
The connection was made in the same manner as in Example 4 except that the relaxation rate of the connected fiber yarn and the connecting fiber yarn at the time of preliminary entanglement was changed as shown in Table 1. The process pass rate was as shown in Table 1.

(Comparative Example 4)
At the time of this entanglement, the connection was made in the same manner as in Example 1 except that the compressed air pressure was 0.1 MPa, the injection time was 10 seconds, and the length shrinkage was changed as described in Table 1. The process pass rate was as shown in Table 1.

(Comparative Example 5)
At the time of this entanglement, the connection was made in the same manner as in Example 3 except that the compressed air pressure was 1.0 MPa and the length shrinkage rate was changed as described in Table 1. The process pass rate was as shown in Table 1.

(Comparative Examples 6 and 7)
The connection was made in the same manner as in Example 1 except that the number of filaments of the connected fiber yarn and the connecting fiber yarn was changed as shown in Table 1. The process pass rate was as shown in Table 1.

11: Connected fiber yarn 11a: Filament yarn of connected fiber yarn 12: Pre-entangled portion 13: Main entangled portion 15: Connected fiber yarn 15a: Filament yarn of connected fiber yarn 21, 23: Clamping mechanism 25: Entangling device 29: Entangling means 29a: Flow direction of high-pressure fluid 31: First fiber yarn 33: Second fiber yarn 35: Third fiber yarn

Claims (5)

A method for connecting fiber yarns, wherein two connected fiber yarns that generate heat by a chemical reaction by heating to 200-300 ° C. in air are connected via connecting fiber yarns that do not generate heat by the chemical reaction. ,
The connected fiber yarns and the connected fiber yarns are aligned and overlapped with the connected fiber yarns and the connected fiber yarns having 1-4 times the number of filaments of the connected fiber yarns. Form an overlapping part,
After sandwiching the overlapped portion and injecting fluid to the overlapped portion to form a preliminary entangled portion,
A method for connecting fiber yarns , wherein a fluid is injected into the preliminary entangled portion to form a main entangled portion in the preliminary entangled portion so that a length shrinkage rate is 1 to 40% . The preliminary interlaced parts, the sandwich said overlapping portion so as to be connected fiber yarn and relaxation rate of the connection fiber yarn is 0.03-2%, respectively, in the overlapping portion, the fluid in the overlapping portion The method for connecting fiber yarns according to claim 1, wherein the fiber yarns are formed by spraying.   The method for connecting fiber yarns according to claim 1, wherein the number of filaments of the connected fiber yarns is 3000-50000.   The method for connecting fiber yarns according to claim 1, wherein the connected fiber yarns are made of acrylic fibers, and the connecting fiber yarns are made of flame-resistant fibers. The manufacturing method of carbon fiber including the process of connecting a fiber yarn by the connection method of the fiber yarn of Claims 1-4 .

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