Polyhydroxyalkanoate warp-knitted hernia repair patch and method of making same

Abstract

The present application relates to a kind of polyhydroxyalkanoate warp hernia repair sheet and its preparation method.Preparation method includes: respectively to PHA monofilament and water-soluble auxiliary fiber are warped, prepare PHA beam and water-soluble fiber beam;Warp knitting is carried out, water-soluble auxiliary fiber is used as temporary loop auxiliary yarn, with PHA monofilament respectively is sent yarn by different combing, according to preset interlacing number code is woven, obtains the preliminary blank mesh containing water-soluble auxiliary fiber;Remove the water-soluble auxiliary fiber, and then heat setting is carried out, obtains the warp hernia repair sheet formed by PHA monofilament.The present application uses PHA monofilament as main yarn, and thin filament diameter water-soluble auxiliary fiber is used as auxiliary yarn to carry out collaborative warp knitting, can improve the yarn breakage, needle missing, loop slippage and mesh irregular problem that PHA monofilament is prone to occur when high-speed warp knitting, improve the stability of warp knitting process and mesh structure uniformity, obtain the hernia repair sheet of stable structure, low defect rate and by pure PHA material.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and in particular to a polyhydroxyalkanoate warp-knitted hernia repair patch and its preparation method. Background Technology

[0002] Hernias are a common surgical condition, and hernia repair patch implantation is one of the most common methods for treating inguinal hernias, incisional hernias, and abdominal wall hernias. Currently used hernia repair patches mainly include non-absorbable patches, partially absorbable patches, and bio-patches. Non-absorbable patches are typically made of polymers such as polypropylene (PP), polyester (PET), or polyvinylidene fluoride (PVDF), providing long-term mechanical support after implantation. However, due to the permanent retention of the material in the body, they can easily cause long-term complications such as chronic inflammation, foreign body sensation, chronic pain, patch shrinkage, tissue adhesion, and erosion of adjacent tissues. Partially absorbable patches, while incorporating biodegradable components to reduce foreign body residue, still retain non-absorbable materials, making it difficult to fundamentally avoid long-term foreign body reactions. Bio-patches generally suffer from limited sourcing, poor batch stability, insufficient mechanical properties, and asynchronous degradation rates with tissue repair. Therefore, developing hernia repair materials that combine good mechanical support with complete biodegradability has become an important research direction in this field.

[0003] Polyhydroxyalkanoates (PHA) are a class of natural biopolyesters synthesized by microbial fermentation. They possess excellent biocompatibility, biodegradability, and controllable mechanical properties. Their typical degradation product, 3-hydroxybutyric acid (3HB), is one of the most common ketone bodies in human blood and does not cause immune rejection or metabolic toxicity. Therefore, it is considered an ideal candidate material for preparing fully biodegradable hernia repair patches. Using PHA to prepare hernia repair patches can provide necessary mechanical support during tissue repair and gradually degrades as new tissue forms, potentially reducing complications caused by long-term foreign body retention.

[0004] For hernia repair patches, warp-knitted structures offer advantages such as uniform pore size, stable mechanical properties, good flexibility, and suitability for large-scale continuous production. Therefore, warp knitting is an important method for preparing hernia repair patches. However, when PHA monofilaments are directly used in high-speed warp knitting at 300–1000 r / min, their yarn processing performance differs significantly from that of traditional materials such as polypropylene. PHA monofilaments typically exhibit high rigidity, insufficient flexibility, and poor loop stability. During high-speed warp knitting, they are prone to yarn shifting, unhooking, skipped stitches, missed stitches, and broken yarns. This results in unstable loop structure formation, poor mesh size consistency, and a high rate of knitting defects, severely impacting continuous production efficiency and final product quality.

[0005] Existing technologies typically improve processing performance by reducing weaving speed, adjusting process parameters, or optimizing material composition, but it is still difficult to balance the processing stability of high-speed warp knitting, the uniformity of the mesh structure, and the pure PHA composition of the final implanted material.

[0006] Therefore, it is necessary to provide a warp knitting preparation process suitable for PHA monofilaments, so as to obtain a hernia repair patch with stable structure, low defect rate and composed of PHA material while ensuring the stability of high-speed warp knitting processing, so as to meet the clinical application needs of fully biodegradable hernia repair materials. Summary of the Invention

[0007] In the prior art, PHA monofilaments are prone to yarn deviation, unhooking, skipped stitches, missed stitches, and broken yarns during high-speed warp knitting, which makes it difficult to form a stable loop structure, resulting in poor mesh size consistency and a high knitting defect rate. Therefore, the present invention provides a polyhydroxyalkanoate warp-knitted hernia repair patch and its preparation method to solve the above problems.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing a polyhydroxyalkanoate warp-knitted hernia repair patch, comprising the following steps:

[0009] S1. PHA monofilament and water-soluble auxiliary fiber are warped separately to prepare PHA warp beams and water-soluble fiber warp beams; S2. Perform warp knitting, using water-soluble auxiliary fibers as temporary loop-forming auxiliary yarns, feeding them and PHA monofilaments through different combs, and knitting them according to the preset padding number to obtain a preliminary web containing water-soluble auxiliary fibers. S3. Remove the water-soluble auxiliary fibers and then perform heat setting to obtain a warp-knitted hernia repair patch composed of PHA monofilaments.

[0010] In one implementation, in S1, the PHA monofilament comprises one or more blends / copolymers of poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx).

[0011] In one implementation, the PHA monofilament is P34HB, and the molar content of 4-hydroxybutyrate units in P34HB is 5%~15%.

[0012] In one implementation, in S1, the water-soluble auxiliary fiber includes one or more of water-soluble polyvinyl alcohol fiber (PVA), water-soluble polyethylene glycol-based fiber, or water-soluble polyacrylate fiber.

[0013] In one implementation, in S1, the diameter of the water-soluble auxiliary fiber is smaller than the diameter of the PHA monofilament.

[0014] In one implementation, the diameter of the PHA monofilament is 0.15~0.25 mm and the breaking strength is ≥5N, and the diameter of the water-soluble auxiliary fiber is 0.05~0.15 mm.

[0015] In one implementation, in S2, the PHA monofilament is threaded into the front comb GB1 as the main yarn, and the water-soluble auxiliary fiber is threaded into the back comb GB2 as the auxiliary yarn for weaving. The front comb GB1 adopts a two-needle warp plain weave, a two-needle warp satin weave, or a three-needle warp satin weave; the back comb GB2 adopts a chain weave, a warp plain weave, or a reverse weft weave.

[0016] In one implementation, step S3 specifically includes: immersing the initial blank mesh in pure water at 40-80°C for 5-30 minutes, performing ultrasonic or oscillating water bath during the immersion process, changing the water bath and rinsing 3-6 times during the process, and obtaining pure PHA warp-knitted mesh after drying.

[0017] In one implementation, in S3, the prepared pure PHA hernia repair patch has a thickness of 0.45~0.72 mm, a pore size of 0.4~1.2 mm, and a mesh density of 52~66 pores / cm². 2 The weight per unit area is 172~245 g / m² 2 Weaving defect rate ≤ 8 pieces / m 2 Both longitudinal tensile strength and transverse tensile strength are ≥20 N / cm.

[0018] Secondly, the present invention also provides a polyhydroxyalkanoate warp-knitted hernia repair patch, which is prepared by the above-mentioned method for preparing polyhydroxyalkanoate warp-knitted hernia repair patches.

[0019] Beneficial effects: The preparation method of the polyhydroxyalkanoate warp-knitted hernia repair sheet provided by the present invention uses PHA monofilament as the main yarn and fine-diameter water-soluble auxiliary fibers as auxiliary yarns for synergistic warp knitting. Among them, the water-soluble auxiliary fibers play a role in guiding, constraining and stabilizing the loop formation of PHA monofilament during the knitting process. After the initial web is formed, the auxiliary fibers are removed, and finally a warp-knitted hernia repair sheet with a regular structure made of pure PHA material is obtained. This method can improve the problems of yarn breakage, missed needles, loop slippage and irregular mesh that are prone to occur during high-speed warp knitting of PHA monofilament, improve the stability of the warp knitting process and the uniformity of the web structure, and obtain a hernia repair sheet with stable structure, low defect rate and made of pure PHA material. Attached Figure Description

[0020] Figure 1This is a flowchart of the preparation method of the polyhydroxyalkanoate warp-knitted hernia repair patch provided by the present invention; Figure 2 This is the yarn padding motion diagram provided in Example 1; Figure 3 This is the yarn padding motion diagram provided in Example 2; Figure 4 This is a microscopic image of the initial preform mesh structure containing water-soluble auxiliary fibers; Figure 5 Microscopic structure of pure PHA warp-knitted hernia repair patch obtained after water-soluble removal of auxiliary fibers; Figure 6 This is a comparison diagram of the polyhydroxyalkanoate warp-knitted hernia repair patch prepared in Example 1 and the product of Comparative Example 1.

[0021] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Furthermore, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., described below refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the technical features involved in the various embodiments of the invention can be combined with each other as long as they do not conflict with each other.

[0023] For details, please refer to [link / reference]. Figure 1 , Figure 1 This is a flowchart illustrating the steps of preparing the polyhydroxyalkanoate warp-knitted hernia repair patch provided by the present invention. The present invention provides a method for preparing a polyhydroxyalkanoate warp-knitted hernia repair patch, comprising the following steps: S1. PHA monofilament and water-soluble auxiliary fiber are warped separately to prepare PHA warp beams and water-soluble fiber warp beams; S2. Perform warp knitting, using water-soluble auxiliary fibers as temporary loop-forming auxiliary yarns, feeding them and PHA monofilaments through different combs, and knitting them according to the preset padding number to obtain a preliminary web containing water-soluble auxiliary fibers. S3. Remove the water-soluble auxiliary fibers and then perform heat setting to obtain a warp-knitted hernia repair patch composed of PHA monofilaments.

[0024] In the preparation method provided by this invention, water-soluble auxiliary fibers temporarily traction, support, loop formation, and stabilization of PHA monofilaments during the weaving stage, reducing the possibility of monofilament slippage, missed needles, yarn breakage, or unstable loop formation. Conventional warp knitting equipment allows the PHA monofilaments to form a more stable mesh structure. The water-soluble auxiliary fibers, after removal, are not retained as permanent components, resulting in a mesh with PHA as the main component and fewer impurities. Heat setting stabilizes the mesh size, thickness, and width, reducing structural shrinkage and deformation during subsequent use.

[0025] Specifically, in S1, the PHA monofilament includes one or more blends / copolymers of poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx). PHB has high structural regularity, is hard and brittle, and its mechanical properties and melting point are similar to polypropylene (PP), but it has a narrow processing window, low elongation at break, and high brittleness. Compared to PHB, PHBV still has higher hardness; however, with the introduction of the 3HV monomer, its ductility and toughness are improved to some extent. PHBHHx belongs to short-chain and medium-long-chain copolymer PHA. Compared to PHB, the introduction of the long-chain monomer 3HHx reduces the material's hardness, increases its ductility, and significantly improves its mechanical properties. P34HB possesses both high strength and ductility. With the introduction of 4HB monomer, the thermal stability of P34HB is significantly improved, its processability is enhanced, and its material properties are adjustable. Preferably, the PHA monofilament is P34HB, and the molar content of 4-hydroxybutyrate units in the P34HB is 5%~15%.

[0026] Specifically, the diameter of the PHA monofilament is 0.15~0.25 mm, and the breaking strength is ≥5N. If the diameter of the PHA monofilament is too small, it may lead to yarn breakage and insufficient mesh strength; if it is too large, it may increase the mesh thickness, stiffness, and amount of foreign matter. Preferably, the diameter of the PHA monofilament is 0.18~0.20 mm, and the breaking strength is ≥6N.

[0027] In S1, the water-soluble auxiliary fiber includes one or more of water-soluble polyvinyl alcohol fiber (PVA), water-soluble polyethylene glycol-based fiber, or water-soluble polyacrylate fiber. Preferably, the water-soluble auxiliary fiber is a low-temperature water-soluble PVA with a dissolution temperature of 20~60°C.

[0028] Furthermore, the diameter of the water-soluble auxiliary fiber is smaller than the diameter of the PHA monofilament, and the diameter of the water-soluble auxiliary fiber is 0.05~0.15mm. Selecting a fine-diameter water-soluble auxiliary fiber can guide, balance tension, and constrain the loop formation of the PHA monofilament during the weaving process, significantly reducing the tendency of the PHA monofilament to spring back and unhook at the moment of loop formation, thereby reducing the overall weaving resistance and defect rate.

[0029] In S2, a high-speed medical Raschel warp knitting machine is used, equipped with a double guide bar device including a front guide bar GB1 and a rear guide bar GB2. PHA monofilaments are threaded into the front guide bar GB1 as the main yarn, and water-soluble auxiliary fibers are threaded into the rear guide bar GB2 as auxiliary yarns. Knitting is performed according to a preset yarn padding number to obtain a preliminary web containing water-soluble auxiliary fibers. During high-speed warp knitting, the water-soluble auxiliary fibers are used as temporary loop-forming stabilizing yarns, fed separately from the PHA monofilaments through different guide bars. This allows the auxiliary fibers to limit the deviation of the PHA monofilaments and maintain loop stability during knitting.

[0030] Furthermore, the yarn threading method is full threading, 1 thread 1 gap, or 2 thread 2 gaps, preferably full threading on the front guide bar and 1 thread 1 gap on the back guide bar. The front guide bar GB1 adopts a two-needle warp plain weave, a two-needle warp satin weave, or a three-needle warp satin weave, preferably a two-needle warp plain weave (1-0 / 1-2 / / ) or a three-needle warp satin weave (1-0 / 3-4 / / ); the back guide bar GB2 adopts a chain weave, warp plain weave, or reverse weft weave, preferably a two-needle warp plain weave (1-0 / 1-2 / / ).

[0031] In one embodiment, the padding movements of the front guide bar GB1 and the rear guide bar GB2 are as follows: GB1 uses a two-needle warp plain weave with padding yarn numbers 1-0 / 1-2 / / ; GB2 uses a two-needle warp plain weave with padding yarn numbers 1-0 / 1-2 / / . In this embodiment, the PHA main yarn and the water-soluble auxiliary yarn alternately form loops synchronously between adjacent needle positions. The auxiliary yarn forms a symmetrical constraint on the PHA loops, forming a relatively balanced initial mesh, suitable for hernia repair patches with medium mesh density and symmetrical and balanced structure.

[0032] In another preferred embodiment, the padding movements of the front guide bar GB1 and the rear guide bar GB2 are as follows: GB1 adopts a three-needle warp satin weave with padding yarn numbers 1-0 / 3-4 / / ; GB2 adopts a two-needle warp plain weave with padding yarn numbers 1-0 / 1-2 / / . In this embodiment, the PHA main yarn extends obliquely with a large span to form the main skeleton structure, and the water-soluble auxiliary yarn alternates in small loops between adjacent needle positions, cross-clamping and constraining the PHA loops, thereby effectively suppressing the rebound and unhooking of the PHA monofilaments at the moment of loop formation, forming a large-mesh, lightweight initial fabric.

[0033] In step S3, the removal of the water-soluble auxiliary fibers specifically includes: immersing the initial fabric mesh in pure water at 40-80°C for 5-30 minutes, subjecting it to ultrasonic or oscillating water bath during the immersion process, changing the water bath and rinsing 3-6 times during this period, and then drying to obtain a pure PHA warp-knitted mesh. The ultrasonic or oscillating water bath accelerates the dissolution rate and improves the uniformity of the removal effect; further, changing the water bath and rinsing ensures that the water-soluble components are completely removed. During the water-soluble removal process, the removal conditions are mild and require no chemical reagents, thus avoiding degradation or contamination of PHA, and the final mesh obtained is 100% pure PHA material.

[0034] During the removal of the water-soluble auxiliary fibers, warm water at 40-80°C is used to promote their dissolution, while avoiding the use of strong acids, strong alkalis, or organic solvents that may damage the PHA. Ultrasonic or oscillatory stimulation promotes water penetration into the yarn interlacing area, accelerating the dissolution of the auxiliary fibers. Multiple water changes maintain the concentration gradient, reducing the re-adhesion or retention of dissolved polymers. Rinsing 3-6 times helps reduce auxiliary material residue, improve mesh purity, and enhance implantation safety.

[0035] In step S3, heat setting specifically includes: a heat setting temperature of 100~140℃, a pressure of 100~500 N, and a time of 30~60 min. After heat setting, the material is cooled to room temperature and the pressure is removed to obtain a pure PHA hernia repair patch. Heat setting under the above temperature, pressure, and time conditions effectively releases residual internal stress in the mesh, stabilizes the mesh structure, and prevents excessive thermal degradation of PHA.

[0036] The pure PHA hernia repair patch prepared by the above method has a thickness of 0.45~0.72 mm, a pore size of 0.4~1.2 mm, and a mesh density of 52~66 pores / cm². 2 The weight per unit area is 172~245 g / m² 2 Weaving defect rate ≤ 8 pieces / m 2 Both longitudinal tensile strength and transverse tensile strength are ≥20 N / cm.

[0037] In S3, after weaving, water-soluble auxiliary fibers are removed by soaking in warm water combined with ultrasound or vibration and multiple rinsing, ensuring that the auxiliary yarn is not retained as a permanent component. This process yields a warp-knitted mesh with PHA as the main component while maintaining weaving performance. Further heat setting stabilizes the loop structure, aperture, thickness, and width of the mesh. By coordinating the PHA material composition, main and auxiliary yarn diameters, and warp knitting structure, the resulting hernia repair patch exhibits a more regular mesh structure, a lower weaving defect rate, and more balanced longitudinal and transverse load-bearing capacity, thus achieving a balance between mechanical support, flexibility, pore structure, and material usage.

[0038] The present invention will further illustrate the technical solution provided by the present invention through the following embodiments and verification experiments.

[0039] Example 1 This embodiment provides a method for preparing a polyhydroxyalkanoate warp-knitted hernia repair patch, with the following specific steps: S1. The PHA monofilament and water-soluble auxiliary fiber are warped separately. The PHA monofilament is P34HB monofilament (4-hydroxybutyrate unit molar content of about 8%), with a diameter of 0.19 mm and a breaking strength of 6.2 N. The water-soluble auxiliary fiber is low-temperature water-soluble PVA monofilament with a diameter of 0.10 mm and a dissolution temperature of 20℃.

[0040] Warping is performed using a slitting warping machine, with a PHA warp beam warping tension of 0.6 cN / dtex, a warping speed of 200 m / min, and a winding density of approximately 0.55 g / cm³. 3 The total number of warp ends is 240, and the warp beam width is 10 inches; the warping tension of the water-soluble fiber warp beam is 0.20 cN / dtex, the warping speed is 300 m / min, and the total number of warp ends is 240.

[0041] S2. Warp knitting is performed using a high-speed medical Raschel warp knitting machine (machine number E22), with double comb bars GB1 and GB2 installed. Among them, the front comb bar GB1 is fully threaded with P34HB monofilament, and the rear comb bar GB2 is fully threaded with water-soluble PVA monofilament.

[0042] See Figure 2 , Figure 2 This is the yarn padding motion diagram provided in Example 1, where the front guide bar GB1 uses a two-needle warp plain weave, and its yarn padding number is 1-0 / 1-2 / / ; the rear guide bar GB2 also uses a two-needle warp plain weave, and its yarn padding number is 1-0 / 1-2 / / . In the diagram, 0, 1, and 2 are the needle positions of the warp knitting machine, solid dots represent the needle positions, and continuous curves represent the yarn padding motion trajectory between adjacent rows.

[0043] The warp knitting parameters are: machine speed 900 rpm, PHA warp tension approximately 11 cN / yarn, water-soluble fiber warp tension approximately 4.5 cN / yarn, and tension 10 N / m width.

[0044] The number of weaving defects in the continuously woven initial wire mesh is approximately 3 per meter. 2 .

[0045] S3. Water-soluble removal of auxiliary fibers: Immerse the raw mesh in 45℃ pure water for 10 min, with ultrasonic water bath assistance (frequency 40 kHz), during which the 45℃ pure water is replaced twice; then rinse 4 times in room temperature pure water, each time for about 4 min; vacuum dry (40℃, 2 h).

[0046] Heat setting: The mesh is laid flat on the hot press plate, and a pressure of about 300 N is applied. It is then heat-set at 130℃ for 45 minutes. After heat setting, it is cooled to room temperature and the pressure is removed to obtain a pure PHA hernia repair patch.

[0047] See also Figure 4 and Figure 5 , Figure 4 This is a microscopic image of the initial web structure containing water-soluble auxiliary fibers. Figure 5 The microstructure of the pure PHA warp-knitted hernia repair patch obtained after removing the auxiliary fibers with water shows that the water-soluble auxiliary fibers have been completely removed. The water-soluble auxiliary fibers can be completely dissolved and removed with warm water after weaving, eliminating the need to retain a second type of permanent structural fiber. Through ultrasonic / oscillation-assisted dissolution, multiple water bath replacements and rinsing, the residual auxiliary fibers can be controlled to an extremely low level, resulting in a final product of 100% pure PHA material, meeting the purity requirements for implantable medical devices.

[0048] The obtained pure PHA hernia repair patch was subjected to performance testing. The testing methods were as follows: thickness was tested according to the method specified in GB / T 3820-1997; pore size was measured using an optical microscope (equipped with a micrometer); mesh density was determined by counting pores within a specified area; weight per unit area was tested according to the method specified in GB / T 24218.1-2009; and longitudinal and transverse tensile strengths were tested according to the method specified in GB / T 3923.1-2013. The performance test results are shown in Table 1.

[0049] Example 2 This embodiment examines the effect of using different padding numbers on the preparation results for the front comb GB1. Except for the changes described below, the other conditions are the same as in Example 1.

[0050] Changes: In S2, the front comb GB1 adopts a three-needle warp satin weave (padded yarn number is 1-0 / 3-4 / / ), while the rear comb GB2 still adopts a two-needle warp plain weave (padded yarn number is 1-0 / 1-2 / / ).

[0051] See Figure 3 , Figure 3 This is the yarn padding motion diagram provided in Example 2. In the diagram, 0, 1, 2, and 3 on the left are the front comb bar needle positions, and 0, 1, and 2 on the right are the rear comb bar needle positions. The continuous curve on the left represents the large-span oblique yarn padding motion trajectory of the PHA main yarn between adjacent horizontal rows, and the continuous curve on the right represents the small-amplitude alternating yarn padding motion trajectory of the water-soluble auxiliary fiber between two adjacent needle positions.

[0052] The performance test results are shown in Table 1.

[0053] Example 3 This example examines the effect of PHA monofilament type on the preparation results. Except for the changes described below, all other conditions are the same as in Example 1.

[0054] Change: In S1, the PHA monofilament was replaced with PHBHHx monofilament instead of P34HB (4HB molar content approximately 8%), with a monofilament diameter of 0.19 mm and a breaking strength of 4.8 N. The performance test results are shown in Table 1.

[0055] Example 4 This example investigates the effect of the type of water-soluble auxiliary fiber on the preparation results. Except for the changes described below, all other conditions are the same as in Example 1.

[0056] Changes: In S1, the water-soluble auxiliary fiber was replaced from low-temperature water-soluble PVA monofilament to water-soluble polyacrylate monofilament with a diameter of 0.10 mm and a dissolution temperature of approximately 50°C; correspondingly, the water removal temperature in S3 was adjusted from 45°C to 55°C, while other conditions remained unchanged. Performance test results are shown in Table 1.

[0057] Example 5 This example investigates the effect of the diameter of the water-soluble auxiliary fiber on the preparation results. Except for the changes described below, the other conditions are the same as in Example 1.

[0058] Change: In S1, the diameter of the water-soluble auxiliary fiber was changed from 0.10 mm to 0.06 mm (the diameter of the PHA monofilament remained unchanged at 0.19 mm). The performance test results are shown in Table 1.

[0059] Example 6 This example investigates the effect of PHA monofilament diameter on the preparation results. Except for the changes described below, all other conditions are the same as in Example 1.

[0060] Change: In S1, the diameter of the PHA monofilament was changed from 0.19 mm to 0.22 mm (the diameter of the water-soluble auxiliary fiber remained unchanged at 0.10 mm). The performance test results are shown in Table 1.

[0061] Example 7 This example investigates the effect of the molar content of 4-hydroxybutyrate units in P34HB on the preparation results. Except for the changes described below, the other conditions are the same as in Example 1.

[0062] Change: In S1, the molar content of 4-hydroxybutyrate units in P34HB was increased from 8% to 12%, while other conditions remained unchanged. Performance test results are shown in Table 1.

[0063] Comparative Example 1 (without introducing water-soluble auxiliary fibers) The same PHA monofilament, weaving equipment, and warp knitting process parameters as in Example 1 were used, but PHA monofilaments were inserted into both the front and rear comb bars, and no water-soluble auxiliary fibers were introduced.

[0064] See Figure 6 , Figure 6 This is a comparison diagram of the polyhydroxyalkanoate warp-knitted hernia repair patch prepared in Example 1 and the product of Comparative Example 1. During the weaving process, due to the large diameter, high rigidity, high surface friction coefficient, and high resilience modulus of the PHA monofilament, frequent dehooking and filament breakage failures occurred, forcing a significant reduction in machine speed; even so, the weaving defect rate was still significantly greater than 30 defects / m. 2 The mesh has many areas with missing or skipped stitches, and the mesh structure is disordered, making it impossible to form a qualified hernia repair patch.

[0065] Comparative Example 2 (Water-soluble auxiliary fiber diameter is too large) The same process as in Example 1 was used, but the diameter of the water-soluble auxiliary fiber was changed from 0.10 mm to 0.20 mm.

[0066] The results showed that although the weaving process could be carried out, the water-soluble fibers occupied a large volume in the mesh structure; after the water was removed, the mesh pores were significantly deformed, the pore size increased significantly, and the mesh density decreased significantly, and the mechanical properties could not meet the requirements for the use of hernia repair patches. The performance test results are shown in Table 1.

[0067] Comparative Example 3 (Heat setting temperature too high) The same water-soluble removal steps as in Example 1 (S1, S2, and S3) are used, but the heat setting temperature is increased from 130°C to 160°C.

[0068] The results showed that the obtained mesh exhibited significant yellowing and a marked decrease in mechanical properties; considering significant thermal degradation, the mesh is unsuitable for use as a clinical implant material. Performance test results are shown in Table 1.

[0069] Table 1. Performance index test results of each embodiment

[0070] As shown in Table 1, the present invention uses PHA monofilament and water-soluble auxiliary fibers for double comb warp knitting, and removes the auxiliary fibers after knitting. This can significantly reduce the knitting defect rate of PHA monofilament, improve knitting stability, and obtain a pure PHA warp-knitted hernia repair patch with uniform mesh structure and good mechanical properties.

[0071] Specifically, compared with Comparative Example 1, after introducing water-soluble auxiliary fibers, the weaving defect rate in Example 1 was reduced from more than 30 defects / m² to 3 defects / m², and the longitudinal and transverse tensile strengths were significantly improved, indicating that water-soluble auxiliary fibers can effectively improve the weavability of PHA monofilaments.

[0072] Example 2 shows that by adjusting the warp knitting structure, the mesh size, mesh density, weight per unit area, and mechanical properties can be controlled. Examples 3 and 7 show that different PHA materials and their compositions affect the mechanical properties of the mesh, but all can produce warp-knitted hernia repair sheets with complete structures. Example 4 shows that as long as the auxiliary fibers have suitable water solubility, diameter, and weaving properties, and are combined with appropriate dissolution and removal conditions, different types of water-soluble auxiliary fibers can achieve auxiliary weaving functions. Examples 5 and Comparative Example 2 show that when the auxiliary fibers are too fine, the support, constraint, and auxiliary loop formation of the PHA monofilaments are insufficient, leading to a decrease in loop stability during weaving, resulting in more weaving defects and weakening the effective load-bearing structure of the mesh; when the water-soluble auxiliary fibers are too coarse, they will occupy too much structural space in the initial mesh, and after dissolution and removal, they are prone to forming excessively large gaps, causing mesh deformation, loose structure, and decreased mechanical properties. Therefore, both excessively small and excessively large diameters of water-soluble auxiliary fibers will affect the mesh structure and mechanical properties, and an appropriate auxiliary fiber diameter should be selected. Example 6 shows that increasing the diameter of the PHA monofilament can improve the mesh thickness and tensile strength, but it will increase the weight per unit area and reduce the aperture size. Comparative Example 3 shows that excessively high heat setting temperatures can lead to a decrease in the mechanical properties of the material, which is detrimental to maintaining product performance.

[0073] Table 1 shows that the type and diameter of PHA monofilament, the type and diameter of water-soluble auxiliary fibers, the warp knitting structure, and the heat setting temperature all affect the mesh structure, weight per unit area, mechanical properties, and weaving defect rate of the resulting hernia repair patch. Among these factors, using water-soluble auxiliary fibers of suitable diameter in double-comb warp knitting with PHA monofilament is key to reducing PHA monofilament weaving defects, stabilizing the mesh structure, and improving the mechanical properties of the finished product. By rationally selecting PHA monofilament, water-soluble auxiliary fibers, padding yarn number, and heat setting conditions, pure PHA warp-knitted hernia repair patches with low weaving defect rate, adjustable mesh structure, good mechanical properties, and low auxiliary fiber residue can be obtained.

[0074] In summary, the method for preparing polyhydroxyalkanoate warp-knitted hernia repair sheet provided by this invention can improve the stability of high-speed warp knitting of PHA monofilaments and obtain pure PHA warp-knitted hernia repair sheet without introducing permanent non-PHA fibers. By introducing fine-diameter water-soluble auxiliary fibers to synergistically warp knit with PHA monofilaments, the auxiliary fibers play a triple role in guiding, tension balancing, and constraining the loop formation of the PHA main yarn during the loop formation process. This effectively suppresses the rebound and dehooking of PHA monofilaments, significantly reducing knitting defects such as dehooking, broken yarn, skipped stitches, and missed stitches. The knitting defect rate can be controlled to ≤8 defects / m. 2 This improves the stability of the warp knitting process and yields pure PHA warp-knitted hernia repair sheets with a relatively regular mesh structure and good mechanical properties.

[0075] The patch obtained by this invention is a pure PHA fully biodegradable synthetic polymer material, which avoids long-term complications such as chronic inflammation, foreign body sensation, chronic pain, and adhesion caused by long-term implantation of non-absorbable patches; it also avoids the problem of residual non-absorbable components in some absorbable patches; compared with biological patches, it has advantages such as good batch stability, no immunogenicity risk, controllable mechanical strength, and degradation rate matching tissue regeneration.

[0076] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a polyhydroxyalkanoate warp-knitted hernia repair patch, characterized in that, Includes the following steps: S1. PHA monofilament and water-soluble auxiliary fiber are warped separately to prepare PHA warp beams and water-soluble fiber warp beams; S2. Perform warp knitting, using water-soluble auxiliary fibers as temporary loop-forming auxiliary yarns, feeding them and PHA monofilaments through different combs, and knitting them according to the preset padding number to obtain a preliminary web containing water-soluble auxiliary fibers. S3. Remove the water-soluble auxiliary fibers and then perform heat setting to obtain a warp-knitted hernia repair patch composed of PHA monofilaments.

2. The method for preparing the polyhydroxyalkanoate warp-knitted hernia repair patch according to claim 1, characterized in that, In S1, the PHA monofilament includes one or more blends / copolymers of poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(4-hydroxybutyrate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate).

3. The method for preparing the polyhydroxyalkanoate warp-knitted hernia repair patch according to claim 2, characterized in that, The PHA monofilament is P34HB, and the molar content of 4-hydroxybutyrate units in P34HB is 5%~15%.

4. The method for preparing the polyhydroxyalkanoate warp-knitted hernia repair patch according to claim 1, characterized in that, In S1, the water-soluble auxiliary fiber includes one or more of water-soluble polyvinyl alcohol fiber, water-soluble polyethylene glycol-based fiber, or water-soluble polyacrylate fiber.

5. The method for preparing the polyhydroxyalkanoate warp-knitted hernia repair patch according to claim 1, characterized in that, In S1, the diameter of the water-soluble auxiliary fiber is smaller than the diameter of the PHA monofilament.

6. The method for preparing the polyhydroxyalkanoate warp-knitted hernia repair patch according to claim 5, characterized in that, The diameter of the PHA monofilament is 0.15~0.25 mm and the breaking strength is ≥5N. The diameter of the water-soluble auxiliary fiber is 0.05~0.15 mm.

7. The method for preparing the polyhydroxyalkanoate warp-knitted hernia repair patch according to claim 1, characterized in that, In S2, the PHA monofilament is threaded into the front comb GB1 as the main yarn, and the water-soluble auxiliary fiber is threaded into the back comb GB2 as the auxiliary yarn for weaving. The front comb GB1 adopts a two-needle warp plain weave, a two-needle warp satin weave, or a three-needle warp satin weave; the back comb GB2 adopts a chain weave, a warp plain weave, or a reverse weft weave.

8. The method for preparing the polyhydroxyalkanoate warp-knitted hernia repair patch according to claim 1, characterized in that, In step S3, the specific steps include: immersing the initial blank mesh in pure water at 40-80°C for 5-30 minutes, performing ultrasonic or oscillating water baths during the immersion process, changing the water bath and rinsing 3-6 times during the process, and obtaining pure PHA warp-knitted mesh after drying.

9. The method for preparing the polyhydroxyalkanoate warp-knitted hernia repair patch according to claim 1, characterized in that, In S3, the prepared pure PHA hernia repair patch has a thickness of 0.45–0.72 mm, a pore size of 0.4–1.2 mm, and a mesh density of 52–66 pores / cm². 2 The weight per unit area is 172~245 g / m² 2 Weaving defect rate ≤ 8 pieces / m 2 Both longitudinal tensile strength and transverse tensile strength are ≥20 N / cm.

10. A polyhydroxyalkanoate warp-knitted hernia repair patch, characterized in that, It is prepared by the method of any one of claims 1 to 9 for the preparation of polyhydroxyalkanoate warp-knitted hernia repair patch.

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