Expanding and stretching device of circular-diameter expanded polytetrafluoroethylene monofilament sewing thread for medical operation

Abstract

The invention discloses a bulking and stretching device of a circular diameter expanded polytetrafluoroethylene monofilament sewing thread for medical surgery, which comprises a bulking heating device and a stretching heating device which are arranged in sequence, and a front air cooling area and a rear air cooling area are arranged between the bulking heating device and the stretching heating device; the puffing heating device comprises a first heating cavity, first godet wheels are arranged on the two sides of the first heating cavity, a first electric heating plate is arranged in the first heating cavity, and a godet groove is formed in the first electric heating plate; the stretching heating device comprises a second heating cavity, and a second electric heating plate is arranged in the second heating cavity. The medical expanded polytetrafluoroethylene sewing thread with the thread diameter of 0.05-0.30 mm can be manufactured, the material has good chemical stability, does not reject, does not breed bacteria and the like and is compatible with human tissues, meanwhile, when the medical expanded polytetrafluoroethylene sewing thread is used, forking is avoided during sewing, the situation that dirt is left due to distortion of a thread body after an operation is reduced, and the medical expanded polytetrafluoroethylene sewing thread is suitable for medical use. And the probability of bacterial infection is reduced while the patient feels comfortable.

Description

Technical Field

[0001] The invention relates to the technical field of medical suture thread devices, and in particular to a device for expanding and stretching a circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery. Background Art

[0002] At present, the polymer material polytetrafluoroethylene (PTFE) has been widely used in the medical field, such as artificial blood vessels, artificial skin, heart valves, breast augmentation and rhinoplasty fillers, non-absorbable surgical sutures, etc. made of expanded polytetrafluoroethylene (ePTFE). PTFE products can be used for a long time in a very wide temperature range (-196 ~ 260 ° C), have very good chemical corrosion resistance, and can not be corroded by chemical solvents such as concentrated sulfuric acid, concentrated hydrochloric acid and caustic soda. In terms of physical properties, its friction coefficient is very low (the friction coefficient of fiber materials is less than 0.1) and is not affected by ultraviolet radiation. After long-term experiments, the medical community has also found that the expanded material of PTFE is biocompatible. The expansion of PTFE means that due to the long molecular chain of PTFE and the lack of branching, under certain temperature conditions, the molecular chains in the high elastic state range are stretched and oriented, and gaps (called micropores in the industry) will be formed between the molecular chains, making the PTFE material elastic and soft. After high-multiple multi-directional stretching, micro-permeable pores can also appear.

[0003] GORE, an American company, invented ePTFE in 1969 and certified that in addition to the inherent stability, chemical resistance, heat resistance, UV resistance, and good wear resistance and low friction characteristics of PTFE, expanded polytetrafluoroethylene (ePTFE) has broadened its application range due to its creep resistance and wear resistance. It can be used as an excellent medical polymer material for human medical treatment and the manufacture of medical devices. Due to its extremely stable chemical resistance (no decomposition), human tissue cells and blood vessels can grow into its expanded micropores to form tissue connections without side effects such as carcinogenesis and sensitization, just like autologous tissue. This tissue generation method of tissue healing is superior to the traditional silicone rubber fiber wrapping tissue healing method. At present, expanded polytetrafluoroethylene is mostly used as artificial blood vessels, sutures, and facial implants. Multiple documents show that ePTFE is a medical biomaterial with good tissue compatibility and stable chemical properties.

[0005] Polytetrafluoroethylene is a rare substance that has no liquid fluidity in the molten state. Therefore, the fiber material of this material cannot be used to produce products such as monofilaments using melt spinning technology. Currently, this type of monofilament is basically produced by two methods: "paste plunger extrusion method" and "paste film rolling slitting method". The former can produce monofilaments with round wire diameters, while the latter can produce flat wires. The imported products currently used in clinical practice are non-absorbable sutures produced by foreign companies such as Gore and WLGORE&B|BRAUN of Italy (trademarks are GORE- Guoxie injection 20172021669), the product is made of expanded polytetrafluoroethylene (ePTFE). However, in clinical use, doctors reported that this sewing thread would bifurcate during use. Careful observation revealed that the cross-section of the thread was similar to that made from a film roll. After further analysis, it can be determined that the sutures produced by Gore and other companies are made using a slitting process. Bifurcations will cause doctors to have difficulty using the sutures during surgery, causing resistance and discomfort to the patient. In addition, after being twisted during sewing, a layer may form, which is prone to retaining blood, body fluids and other substances, and eventually become dirt, causing bacterial infection on the wound surface.

[0006] The applicant has a mature process for producing PTFE monofilaments using the plunger extrusion process, and holds the invention patent "A method for producing continuous filaments" (ZL 201610621069.5), the invention patent "A method for extruding hydraulic plungers with segmented strokes" (ZL202111054621.4), the utility model "A heating and deoiling device for polytetrafluoroethylene monofilaments" (ZL 202222117953.9) and other original production technologies for producing PTFE monofilaments using the plunger extrusion process. The oil-containing PTFE raw silk extruded using this technology is round in shape and has a very smooth surface. After undergoing special temperature-controlled deoiling, expansion, stretching and other processes that are different from non-expanded PTFE sewing threads, a circular expanded ePTFE monofilament can be obtained. By drawing at different stretching speed ratios, monofilaments of different diameters can be obtained, and after medical treatment, they can be used as non-absorbent expanded polytetrafluoroethylene (ePTFE) surgical sutures for medical use.

[0007] The equipment device for which the invention patent is applied is a device specially designed on the basis of various PTFE monofilament manufacturing processes to achieve the purpose of round diameter, expansion and softness. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a swelling and stretching device for circular diameter expanded polytetrafluoroethylene monofilament sewing thread for medical surgery, which can manufacture medical expanded polytetrafluoroethylene sewing thread with a wire diameter of 0.05-0.30mm. The material has good chemical stability, non-rejection, non-bacterial growth and other compatibility with human tissue. At the same time, no bifurcation will occur during suture during use, which reduces the situation of residual dirt due to twisting of the thread after surgery, and reduces the chance of bacterial infection while making the patient feel comfortable.

[0009] In order to solve the above technical problems, the present invention provides a puffing and stretching device for circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery, characterized in that it includes a puffing heating device and a stretching heating device arranged in sequence, and a front air cooling zone and a rear air cooling zone are arranged between the puffing heating device and the stretching heating device; the puffing heating device includes a first heating cavity, first wire guide wheels are arranged on both sides of the first heating cavity, a first electric heating plate is arranged in the first heating cavity, and a wire guide groove is arranged on the first electric heating plate; the stretching heating device includes a second heating cavity, and a second electric heating plate is arranged in the second heating cavity.

[0010] Furthermore, a sliding cover mechanism is provided on both the first heating cavity and the second heating cavity.

[0011] Further, the wire guide groove is provided with three identical structures, namely, the first groove, the second groove and the third groove, the arc angle of the first wire guide wheel is not greater than 180°, and the parameters of the first heating cavity are as follows: thickness 3-5mm, built-in thermal insulation cotton, inner cavity space width 10-30cm, height 8-12cm, length 80-120cm, the first heating plate is placed in the cavity from the bottom end, and the length and width are adapted to the size of the inner cavity space, and the height is 5-8cm;

[0012] Taking the middle part of the inner cavity height as the standard and the intersection point of the left and right three equal divisions as the center point, penetrate the first heating cavity and make a 1-2 cm hole at the same time, and place an electric heating rod as a heat source;

[0013] The dimensions of the first groove, the second groove and the third groove are 1-1.5 cm in width and 0.8-1.2 cm in depth; and the two ends of the cavity are sealed and three U-shaped openings corresponding thereto are arranged.

[0014] Furthermore, a metal plate of 5-10 cm is extended from the bottom surfaces of both ends of the first heating cavity, and the first wire guide wheel is installed corresponding to the right end of the first groove and the middle part of the second groove, and the diameter of the first wire guide wheel is equal to the distance between the center lines of the first groove and the second groove;

[0015] A first wire guide wheel of the same size is also arranged between the second groove and the third groove, and the first wire guide wheel is driven by a coaxial motor with joint controllable speed.

[0016] Furthermore, the second electric heating plate is an arc-shaped chrome-plated electric heating plate, the edge position of the second electric heating plate is flush with the openings on both sides of the second heating cavity, and the heating wire carried by the second electric heating plate is attached to the heating plate and travels in an S stroke;

[0017] The second electric heating plate has a width of 10-30 cm, a thickness of 5-8 cm, and a length of 80-120 cm. In the length direction, the surface layer of the second electric heating plate is a parabolic arc surface with an arc angle of 5°-8°, and is chrome-plated and polished.

[0018] Furthermore, it comprises a stretching device system, wherein the stretching device system comprises a holding roller group and an involving roller group.

[0019] Furthermore, the holding roller group includes a main roller driven by a power, a pressure roller and a wire separation roller which form a pair with the main roller;

[0020] The main roller and the driven pressure roller have surface layers made of fluorosilicone rubber;

[0021] The surface of the wire separation roller is provided with 8-10 wire grooves, each of which is semicircular and has a depth of 0.2-0.5 mm.

[0022] Beneficial effects of the present invention:

[0023] 1. Both heating chambers adopt heat preservation chamber heating, the temperature is controllable, the wire body is heated evenly, the heat dissipation is reduced, and the energy loss is reduced; the sliding cover opens automatically to avoid burns and scalds to employees and protect their health.

[0024] 2. The first electric heating plate adopts a groove-type puffing heating plate, which is conducive to wire guiding, can avoid wire entanglement, and improve wire winding efficiency.

[0025] 3. The curvature (α) of the contact surface between the two folding guide wheels and the wire is ≤180°, which avoids excessive stretching of the wire body in an incompletely expanded state under large curvature, causing deformation of the wire; and the wire guide wheel driven by a micro motor can also reduce the friction caused by the passive rotation and folding of the wire, causing it to deform under force.

[0026] 4. The front and rear air cooling zones before entering the holding roller and the drawing roller can effectively cool the heated wire body, allowing the molecular structure to quickly solidify and form, and prevent non-recoverable deformation caused by the clamping and squeezing of the holding roller.

[0027] 5. The holding roller group at the front end of the drafting device system consists of a main roller, a pressure roller and a wire-separating roller. Features include: ① In order to increase and stabilize the holding force and overcome the weakness of wire slippage due to the low friction coefficient of polytetrafluoroethylene, the active roller and the pressure roller are designed as fluorosilicone rubber coatings, which can not only solve the problem of stable holding force, but also reduce the extrusion force of the roller on the wire due to the moderate softness of fluorosilicone rubber, thereby reducing the deformation of the wire body; at the same time, a wire-separating roller is used at the side end of the main roller. The wire is constrained by the wire groove of the wire-separating roller and can be evenly distributed on the main roller surface to prevent mutual entanglement and extrusion deformation.

[0028] 6. The second electric heating plate of the stretching heating device is designed to be a slightly convex arc, and the second wire guide wheels at both ends are slightly lower than the plate surface, giving the wire a certain tension so that it is evenly heated during the stretching process; and the smooth chrome-plated surface of the second electric heating plate can protect the wire from scratches or fuzzing due to abrasion.

[0029] 7. The design of the combination of the main holding roller and the wire-splitting roller as well as the drafting roller and the wire-splitting roller utilizes the irregular ellipse formed by two unequal circles to increase and stabilize the holding force between the wire and the roller; and the wire grooves carved on the auxiliary rollers, which can embed the wires, increase the friction of the wire rollers while protecting the roundness of the wire diameter, and at the same time play a role in wire separation, preventing the wires from being entangled and squeezed on the drafting rollers. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic structural diagram of the expansion heating device of the present invention.

[0031] Figure 2 It is a schematic diagram of the first heating cavity structure of the present invention.

[0032] Figure 3 It is a cross-sectional schematic diagram of the first heating cavity of the present invention.

[0033] Figure 4 It is a schematic structural diagram of the stretching and heating device of the present invention.

[0034] Figure 5 It is a schematic structural diagram of the second electric heating plate of the present invention.

[0035] Figure 6 It is a schematic diagram of the operating structure of the holding roller group of the present invention.

[0036] Figure 7 It is a schematic diagram of the position and structure of the post-air cooling, the drafting roller group and the wire collection drum of the present invention.

[0037] Figure 8 It is a schematic diagram of the rear air cooling zone and the involved roller group of the present invention.

[0038] Explanation of the numbers in the figure: 1. Puffing heating device; 2. Stretching heating device; 3. First heating cavity; 4. First guide wire wheel; 5. First electric heating plate; 6. First groove; 7. Second groove; 8. Third groove; 9. Second heating cavity; 10. Second guide wire wheel; 11. Second electric heating plate; 12. Sliding cover mechanism; 13. Main roller; 14. Pressure roller; 15. Separating roller; 16. Coaxial motor. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0045] Reference Figures 1 to 8 As shown, an embodiment of a puffing and stretching device for a circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery of the present invention comprises a puffing heating device 1 and a stretching heating device 2 which are arranged in sequence, and a front air cooling zone and a rear air cooling zone are arranged between the puffing heating device 1 and the stretching heating device 2; the puffing heating device 1 comprises a first heating cavity 3, first wire guide wheels 4 are arranged on both sides of the first heating cavity 3, a first electric heating plate 5 is arranged in the first heating cavity 3, and a wire guide groove is arranged on the first electric heating plate 5; the stretching heating device 2 comprises a second heating cavity 9, second wire guide wheels 10 are arranged on both sides of the second heating cavity 9, and a second electric heating plate 11 is arranged in the second heating cavity 9.

[0046] The first heating cavity 3 and the second heating cavity 9 are both provided with a sliding cover mechanism 12; the wire guide groove is provided with three identical structures, namely the first groove 6, the second groove 7 and the third groove 8; the arc angle of the first wire guide wheel 4 is not greater than 180°; the parameters of the first heating cavity 3 are as follows: thickness 3-5mm, built-in thermal insulation cotton, inner cavity space width 10-30cm, height 8-12cm, length 80-120cm, the first heating plate is placed in the cavity from the bottom end, and the length and width of the inner cavity space are adapted to the size of the inner cavity space, and the height is 5-8cm; the inner cavity The middle part of the height is based on the intersection of the left and right three equal parts as the center point, and a 1-2 cm hole is opened while running through the first heating cavity 3, and an electric heating rod is placed in it as a heat source; the dimensions of the first groove 6, the second groove 7 and the third groove 8 are 1-1.5 cm wide and 0.8-1.2 cm deep; and the two ends of the cavity are blocked and three U-shaped openings corresponding to them are set; the bottom surfaces of the two ends of the first heating cavity 3 each extend out a 5-10 cm metal plate, and the first wire guide wheel 4 is installed corresponding to the right end of the first groove 6 and the middle part of the second groove 7, and the first wire guide wheel 4 has a diameter equal to the distance between the center lines of the first groove 6 and the second groove 7; a first wire guide wheel 4 of the same size is also arranged between the second groove 7 and the third groove 8, and the first wire guide wheel 4 is driven by a coaxial motor 16 with joint control and speed regulation; the second electric heating plate 11 is an arc-shaped chrome-plated electric heating plate, and the edge position of the second electric heating plate 11 is flush with the openings on both sides of the second heating cavity 9, and the heating wire carried by the second electric heating plate 11 is attached to the heating plate and travels an S stroke; the second electric heating plate 11 has a width of 10-30 cm, a thickness of 5-8 cm, and a length of 80-1 20cm; in the length direction, the surface layer of the second electric heating plate 11 is a parabolic arc surface with an arc angle of 5°-8°, chrome-plated and polished; it includes a stretching device system, the stretching device system includes a holding roller group and an involving roller group; the holding roller group includes a main roller 13 driven by a power, a pressure roller 14 and a wire separation roller 15 that form a pair of rollers with the main roller 13; the main roller 13 and the driven pressure roller 14 are made of fluorosilicone rubber; the surface of the wire separation roller 15 is machined with 8-10 wire grooves, the wire grooves are semicircular, and the depth is between 0.2-0.5mm.

[0047] Step 1:

[0048] The expansion heating device 1 device part. ① Made of 1-1.5mm metal plate welded, for heat preservation and energy saving, it is used as a heat insulation interlayer with a thickness of 3mm, and built-in aluminum silicate heat insulation cotton. The cavity volume size is 80-120cm long, 10-30cm wide, and 8-12cm high. ② The sliding cover mechanism 12 is an independent part, which can be slid back and forth to open and close, and an external suspended push-pull metal slide rail is installed on the top surface. ③ The first heating cavity 3 and the slide rail are both fixed on the metal wall panel. ④ The first electric heating plate 5 with a wire guide groove is placed in the cavity, and its length and width dimensions are consistent with the length and width dimensions of the cavity, 80-120cm long, 10-30cm wide, and 5-8cm high; it is placed at the bottom of the cavity and above. Three U-shaped grooves of 2-3cm and 1-2cm wide are equidistantly turned on the surface of the metal plate. ⑤ On both sides of the cavity, a metal plate with a thickness of 0.5-1 is welded as a support, and a torque motor is positioned and installed under the metal plate; through the metal plate, at the right end, corresponding to the first groove 6 and the second groove 7 of the heating plate, a first wire guide wheel 4 coaxial with the coaxial motor 16 is installed. The first wire guide wheel 4 is smooth and has a wire guide groove on the edge; the arc angle (α) formed by the contact between the wire guide wheel disc of the first wire guide wheel 4 and the wire is ≤180°, and the wheel disc must be higher than the lower surface of the wire groove to achieve a suspended circulation of the wire; similarly, the first wire guide wheel 4 is installed on the left side of the cavity corresponding to the second groove 7 and the third groove 8. The corresponding angles of the first wire guide wheel 4 and the wire are the same as those designed on the right end. The two first wire guide wheels 4 are linked and controlled and need to be kept synchronized.

[0049] Step 2:

[0050] Stretching heating device 2. ① The material and manufacturing of the second heating cavity 9 and the design process of the sliding cover mechanism 12 are the same as those of the puffing heating device 1. ② The difference is that an electric heating metal plate (that is, the second electric heating plate 11) is built in, the size of which matches the cavity, and the surface needs to be processed into an arc parabola, and the arc angle (α) of the parabola is 3-5°. The formed metal plate is chrome-plated to make the surface reach a mirror finish. ③ The left and right ends of the cavity are designed as active wire guide wheels (that is, the second wire guide wheel 10) that are the same as the puffing cavity. The difference is that the wire guide wheel disc here should ensure that the wire is in close contact with the surface of the heating plate and is heated evenly. ④ This part of the device is also attached to the back metal wall panel support and is linked with other parts.

[0051] Step 3:

[0052] Holding roller device. The holding main roller 13, pressure roller 14 and wire separation roller 15 are all installed on a vertical metal wall panel, where the main roller 13 is an electric driving wheel, the motor is installed on the back of the wall panel, and is coaxially driven with the driving wheel; the pressure roller 14 is designed to be rotatable and can be lifted up when changing the line and stopped at a fulcrum; when in use, it is rotated and lowered, and its own weight plays a role in pressing the line body; the axis of the wire separation roller 15 is installed on the same horizontal line as the driving wheel, and the distance between the two roller axes is 25cm. The diameter of the driving roller is 15cm and the length is 25cm; the diameter of the wire separation roller 15 is 8cm and the length is 25cm, with a total of 10 semicircular grooves engraved, and the depth (R) is 0.2mm.

[0053] Step 4:

[0054] Drafting roller device. Similarly, the main drafting roller and the wire guide roller are installed on the metal wallboard of the same vertical surface. The main drafting roller is installed with a coaxial motor 16 behind the wallboard as the power, which is the active roller, and the wire separation roller 15 is the driven roller; the axis of the drafting roller and the wire separation roller 15 are installed on the same horizontal line, and the distance between the center points of the two rollers is 30cm; the diameter of the main drafting roller is 15cm and the length is 25cm; the diameter of the wire separation roller 15 is 8cm and the length is 25cm, and there are 10 wire semicircular grooves engraved in total, with a depth (R) of 0.2mm.

[0055] Step 5:

[0056] The front air cooling zone and the rear air cooling zone are the front and rear air cooling devices. A controllable air cooler with a power of 1.5KW-3KW is used in two pipelines to cool down the continuous wire before the holding roller group and before the involving roller group in stages to prevent the wire from being squeezed by the holding roller or deformed (flattened) by the drawing roller due to the heat-carrying softness of the wire after entering the roller group. Air cooling is mainly for the curing and shaping of the wire at different stages. The air cooler is a common industrial refrigerant air cooler in the market, which can be debugged and set according to the changes in room temperature. The air outlets of the two air cooling locations are designed to be flat square, with a length of 20-30cm and a width of 2-3cm. They are placed 5-10cm above the silk thread and blow air downward.

[0057] Step 6:

[0058] Wire collection is performed using the wire collection device, with normal settings.

[0059] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A device for expanding and stretching a circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery, characterized in that: It comprises an expansion heating device (1) and a stretching heating device (2) which are arranged in sequence, and a front air cooling zone and a rear air cooling zone are arranged between the expansion heating device (1) and the stretching heating device (2); The puffing heating device (1) comprises a first heating cavity (3), first wire guide wheels (4) are arranged on both sides of the first heating cavity (3), a first electric heating plate (5) is arranged in the first heating cavity (3), and a wire guide groove is arranged on the first electric heating plate (5); The stretching and heating device (2) comprises a second heating cavity (9), second guide wire wheels (10) are arranged on both sides of the second heating cavity (9), and a second electric heating plate (11) is arranged in the second heating cavity (9).

2. The device for expanding and stretching the circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery as claimed in claim 1, characterized in that: The first heating cavity (3) and the second heating cavity (9) are both provided with a sliding cover mechanism (12).

3. The device for expanding and stretching the circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery as claimed in claim 1, characterized in that: The wire guide groove is provided with three identical structures, namely a first groove (6), a second groove (7) and a third groove (8); the arc angle of the first wire guide wheel (4) is not greater than 180°; the parameters of the first heating cavity (3) are as follows: thickness 3-5 mm, built-in thermal insulation cotton, inner cavity space width 10-30 cm, height 8-12 cm, length 80-120 cm, the first heating plate is placed in the cavity from the bottom end, and the length and width are adapted to the size of the inner cavity space, and the height is 5-8 cm; The middle part of the inner cavity height is taken as the central point and the intersection point of the left and right three equal divisions is taken as the central point. A 1-2 cm hole is opened through the first heating cavity (3) and an electric heating rod is placed in it as a heat source. The dimensions of the first groove (6), the second groove (7) and the third groove (8) are 1-1.5 cm in width and 0.8-1.2 cm in depth; and the two ends of the cavity are sealed and three U-shaped openings corresponding thereto are provided.

4. The device for expanding and stretching the circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery as claimed in claim 3, characterized in that: A metal plate of 5-10 cm is extended from the bottom surfaces of both ends of the first heating cavity (3), and the first wire guide wheel (4) is installed corresponding to the right end of the first groove (6) and the middle part of the second groove (7), and the diameter of the first wire guide wheel (4) is equal to the distance between the center lines of the first groove (6) and the second groove (7); A first wire guide wheel (4) of the same size is also arranged between the second groove (7) and the third groove (8), and the first wire guide wheel (4) is driven by a coaxial motor (16) with coordinated speed control.

5. The device for expanding and stretching the circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery as claimed in claim 1, characterized in that: The second electric heating plate (11) is an arc-shaped chrome-plated electric heating plate, the edge position of the second electric heating plate (11) is flush with the openings on both sides of the second heating cavity (9), and the heating wire carried by the second electric heating plate (11) is attached to the heating plate and travels in an S-shaped stroke; The second electric heating plate (11) has a width of 10-30 cm, a thickness of 5-8 cm, and a length of 80-120 cm; in the length direction, the surface layer of the second electric heating plate (11) is a parabolic arc surface with an arc angle of 5°-8°, and is chrome-plated and polished.

6. The device for expanding and stretching the circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery as claimed in claim 1, characterized in that: The invention comprises a stretching device system, wherein the stretching device system comprises a holding roller group and an involving roller group.

7. The device for expanding and stretching the circular expanded polytetrafluoroethylene monofilament sewing thread for medical surgery as claimed in claim 6, characterized in that: The holding roller group comprises a main roller (13) driven by power, a pressure roller (14) and a separator roller (15) which form a pair with the main roller (13); The main roller (13) and the driven pressure roller (14) have surface layers made of fluorosilicone rubber; The surface of the wire separation roller (15) is provided with 8-10 wire grooves, each of which is semicircular and has a depth of 0.2-0.5 mm.

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