DRYING METHOD FOR POLYGLYCOLLIDE WARP-KNITTED SUPPORT MESHES FOR ARTIFICIAL SKIN

Abstract

The invention relates to a drying method for polyglycollide warp-knitted support meshes for artificial skin, specifically comprising: pre-drying, deep drying, and fabric stress relaxation, which are performed sequentially. The drying method can completely remove water in polyglycollide warp-knitted support meshes as well as solvents left during the cleaning process, and can effectively maintain the properties such as tensile strength, pore size, and weight of the polyglycollide warp-knitted support meshes, thus being of great significance for the application of the polyglycollide warp-knitted support meshes in the field of medical artificial skin.

Claims

1. A drying method for polyglycollide warp-knitted support meshes for artificial skin, specifically comprising: pre-drying, deep drying, and fabric stress relaxation, which are performed sequentially, the pre-drying being completed in a vacuum drying oven A, and the deep drying and the fabric stress relaxation being completed in a vacuum drying oven B, wherein: the process of pre-drying comprises: placing a polyglycollide warp-knitted support mesh, which is aired after being cleaned, in the vacuum drying oven A which is connected to a water-circulation vacuum pump, and setting a temperature in the vacuum drying oven A as T.sub.1; starting the water-circulation vacuum pump, keeping the vacuum drying oven running to treat the polyglycollide warp-knitted support mesh in the vacuum drying oven A under a vacuum degree P.sub.1 for a time t.sub.1, and then stopping the water-circulation vacuum pump; and slowly introducing air into the vacuum drying oven A to enable the vacuum drying oven A to return to normal pressure; the process of deep drying comprises: (1) placing the polyglycollide warp-knitted support mesh in the vacuum drying oven B which is connected to a sliding-vane rotary vacuum pump and an inert gas connecting tube; (2) at normal temperature, starting the sliding-vane rotary vacuum pump to decrease a vacuum degree of the vacuum drying oven B to P.sub.2, then stopping the sliding-vane rotary vacuum pump, and introducing an inert gas into the vacuum drying oven B to enable the vacuum drying oven B to return to normal pressure; (3) performing Step (2) multiple times; (4) starting the sliding-vane rotary vacuum pump, keeping the sliding-vane rotary vacuum pump running to perform drying treatment on the polyglycollide warp-knitted support mesh in the vacuum drying oven B under a vacuum degree P.sub.2 and a temperature T.sub.2 for a time t.sub.2; and (5) under the condition where the vacuum degree of the vacuum drying oven B is maintained at P.sub.2, increasing the temperature in the vacuum drying oven B to T.sub.3 at a heating rate T, maintaining the temperature in the vacuum drying oven B at T.sub.3 to treat the polyglycollide warp-knitted support mesh for a time t.sub.3, and stopping the sliding-vane rotary vacuum pump; the process of fabric stress relaxation comprises: introducing an inert gas into the vacuum drying oven B at a rate V, increasing the temperature in the vacuum drying box B to T.sub.4, treating the polyglycollide warp-knitted support mesh at the temperature T.sub.4 for a time t.sub.4, and then cooling the vacuum drying box B to normal temperature.

2. The drying method for polyglycollide warp-knitted support meshes for artificial skin, wherein the temperature T.sub.1 is 25° C.-35° C., the vacuum degree P.sub.1 is 0-400 Pa, and the treatment time t.sub.1 is 1-2.5 h.

3. The drying method for polyglycollide warp-knitted support meshes for artificial skin according to claim 1, wherein the inert gas is one of nitrogen, argon, and helium.

4. The drying method for polyglycollide warp-knitted support meshes for artificial skin according to claim 1, wherein the vacuum degree P.sub.2 of the vacuum drying oven B is 0-50 Pa, Step (2) is performed two or more times in Step (3), the temperature T.sub.2 is 65° C.-75° C., the time t.sub.2 is 3-5 h, the heating rate T is 16° C./h-24° C./h, the temperature T.sub.3 is 85° C.-105° C., and the time t.sub.3 is ⅓-1 h.

5. The drying method for polyglycollide warp-knitted support meshes for artificial skin according to claim 1, wherein in the process of fabric stress relaxation, the rate V is 0.1 L/min-1 L/min, the temperature T.sub.4 is 110℃-130℃, and the time t.sub.4 is 3-5 h.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0024] The invention will be described in further detail below with reference to specific implementations. Those skilled in the art would appreciate that the following examples are merely used to explain the invention, and should not be construed as limitations of the scope of the invention.

Example 1

[0025] This example provides a drying method for polyglycollide warp-knitted support meshes for artificial skin, specifically comprising: pre-drying, deep drying, and fabric stress relaxation, which are performed sequentially.

[0026] The process of pre-drying comprises: a polyglycollide warp-knitted support mesh, which was aired after being cleaned, was placed in a vacuum drying oven A connected to a water-circulation vacuum pump, and a temperature in the vacuum drying oven A was set to 25° C.; the water-circulation vacuum pump was started and kept running to perform drying treatment on the polyglycollide warp-knitted support mesh under a vacuum degree of 390 Pa for 1 h, and then the water-circulation vacuum pump was stopped; air was slowly introduced into the vacuum drying oven A to enable the vacuum drying oven A to return to normal pressure.

[0027] The process of deep drying comprises: [0028] (1) The polyglycollide warp-knitted support mesh was taken out of the vacuum drying oven A, and was placed in a vacuum drying oven B connected to a sliding-vane rotary vacuum pump and a nitrogen connecting tube; [0029] (2) At normal temperature, the sliding-vane rotary vacuum pump was started to decrease a vacuum degree of the vacuum drying oven B to 50 Pa, then the sliding-vane rotary vacuum pump was stopped, and nitrogen with a purity of 98.98% was introduced into the vacuum drying oven B to enable the vacuum drying oven B to return to normal pressure; [0030] (3) Step (2) was performed three times; [0031] (4) The sliding-vane rotary vacuum pump was started and kept running to perform drying treatment on the polyglycollide warp-knitted support mesh under the vacuum degree of 50 Pa and a temperature of 65° C. for 3 h; [0032] (5) Under the condition where the vacuum degree of the vacuum drying oven B is maintained at 50 Pa, the temperature in the vacuum drying oven B was increased to 95° C. at a heating rate of 18° C./h and was maintained at 95° C. to treat the polyglycollide warp-knitted support mesh for 0.5 h, and then, the sliding-vane rotary vacuum pump was stopped.

[0033] The process of fabric stress relaxation comprises: nitrogen was introduced into the vacuum drying oven B at a rate of 0.5 L/min, the temperature in the vacuum drying oven B was increased to 115° C., and the polyglycollide warp-knitted support mesh was treated at the temperature of 115° C. for 4 h; then, the vacuum drying oven B was decreased to normal temperature and the polyglycollide warp-knitted support mesh was taken out of the vacuum drying oven B.

[0034] The weft tensile strength of the polyglycollide warp-knitted support mesh is 800 MPa, the warp tensile strength of the polyglycollide warp-knitted support mesh is 1300 MPa, the weight of the polyglycollide warp-knitted support mesh is 30 g/m.sup.2, and the pore size of the polyglycollide warp-knitted support mesh is 800 .Math.m.

Example 2

[0035] This example provides a drying method for polyglycollide warp-knitted support meshes for artificial skin, specifically comprising: pre-drying, deep drying, and fabric stress relaxation, which are performed sequentially.

[0036] The process of pre-drying comprises: a polyglycollide warp-knitted support mesh, which was aired after being cleaned, was placed in a vacuum drying oven A connected to a water-circulation vacuum pump, and a temperature in the vacuum drying oven A was set to 30° C.; the water-circulation vacuum pump was started and kept running to perform drying treatment on the polyglycollide warp-knitted support mesh under a vacuum degree of 350 Pa for 1.5 h, and then the water-circulation vacuum pump was stopped; air was slowly introduced into the vacuum drying oven A to enable the vacuum drying oven A to return to normal pressure.

[0037] The process of deep drying comprises: [0038] (1) The polyglycollide warp-knitted support mesh was taken out of the vacuum drying oven A, and was placed in a vacuum drying oven B connected to a sliding-vane rotary vacuum pump and a nitrogen connecting tube; [0039] (2) At normal temperature, the sliding-vane rotary vacuum pump was started to decrease a vacuum degree of the vacuum drying oven B to 30 Pa, then the sliding-vane rotary vacuum pump was stopped, and nitrogen with a purity of 99.99% was introduced into the vacuum drying oven B to enable the vacuum drying oven B to return to normal pressure; [0040] (3) Step (2) was performed two times; [0041] (4) The sliding-vane rotary vacuum pump was started and kept running to perform drying treatment on the polyglycollide warp-knitted support mesh under the vacuum degree of 30 Pa and a temperature of 70° C. for 4 h; [0042] (5) Under the condition where the vacuum degree of the vacuum drying oven B is maintained at 30 Pa, the temperature in the vacuum drying oven B was increased to 100° C. at a heating rate of 20° C./h and was maintained at 100° C. to treat the polyglycollide warp-knitted support mesh for 0.6 h, and then, the sliding-vane rotary vacuum pump was stopped.

[0043] The process of fabric stress relaxation comprises: nitrogen was introduced into the vacuum drying oven B at a rate of 0.6 L/min, the temperature in the vacuum drying oven B was increased to 120° C., and the polyglycollide warp-knitted support mesh was treated at the temperature of 120° C. for 4 h; then, the vacuum drying oven B was decreased to normal temperature, and the polyglycollide warp-knitted support mesh was taken out of the vacuum drying oven B, so that drying is completed.

[0044] The weft tensile strength of the polyglycollide warp-knitted support mesh is 861 MPa, the warp tensile strength of the polyglycollide warp-knitted support mesh is 1257 MPa, the weight of the polyglycollide warp-knitted support mesh is 28 g/m.sup.2, and the pore size of the polyglycollide warp-knitted support mesh is 700 .Math.m.

Example 3

[0045] This example provides a drying method for polyglycollide warp-knitted support meshes for artificial skin, specifically comprising: pre-drying, deep drying, and fabric stress relaxation, which are performed sequentially.

[0046] The process of pre-drying comprises: a polyglycollide warp-knitted support mesh, which was aired after being cleaned, was placed in a vacuum drying oven A connected to a water-circulation vacuum pump, and a temperature in the vacuum drying oven A was set to 28° C.; the water-circulation vacuum pump was started and kept running to perform drying treatment on the polyglycollide warp-knitted support mesh under a vacuum degree of 380 Pa for 1.8 h, and then the water-circulation vacuum pump was stopped; air was slowly introduced into the vacuum drying oven A to enable the vacuum drying oven A to return to normal pressure.

[0047] The process of deep drying comprises: [0048] (1) The polyglycollide warp-knitted support mesh was taken out of the vacuum drying oven A, and was placed in a vacuum drying oven B connected to a sliding-vane rotary vacuum pump and a nitrogen connecting tube; [0049] (2) At normal temperature, the sliding-vane rotary vacuum pump was started to decrease a vacuum degree of the vacuum drying oven B to 40 Pa, then the sliding-vane rotary vacuum pump was stopped, and nitrogen with a purity of 99.22% was introduced into the vacuum drying oven B to enable the vacuum drying oven B to return to normal pressure; [0050] (3) Step (2) was performed four times; [0051] (4) The sliding-vane rotary vacuum pump was started and kept running to perform drying treatment on the polyglycollide warp-knitted support mesh under the vacuum degree of 40 Pa and a temperature of 75° C. for 4.5 h; [0052] (5) Under the condition where the vacuum degree of the vacuum drying oven B is maintained at 40 Pa, the temperature in the vacuum drying oven B was increased to 105° C. at a heating rate of 22° C./h and was maintained at 105° C. to treat the polyglycollide warp-knitted support mesh for 1 h, and then, the sliding-vane rotary vacuum pump was stopped.

[0053] The process of fabric stress relaxation comprises: nitrogen was introduced into the vacuum drying oven B at a rate of 0.5 L/min, the temperature in the vacuum drying oven B was increased to 125° C., and the polyglycollide warp-knitted support mesh was treated at the temperature of 125° C. for 4.5 h; then, the vacuum drying oven B was decreased to normal temperature, and the polyglycollide warp-knitted support mesh was taken out of the vacuum drying oven B, so that drying is completed.

[0054] The weft tensile strength of the polyglycollide warp-knitted support mesh is 752 MPa, the warp tensile strength of the polyglycollide warp-knitted support mesh is 1420 MPa, the weight of the polyglycollide warp-knitted support mesh is 25 g/m.sup.2, and the pore size of the polyglycollide warp-knitted support mesh is 1000 .Math.m.

Contrastive Example 1

[0055] Contrastive example 1 differs from Example 1 only in that the process of deep drying in Contrastive example 1 does not comprise Step (5).

[0056] According to the drying method in Examples 1-3 and Contrastive example 1, the cleaning process may be performed in a 100,000 \-level clean room with at a temperature equal to or lower than 30° C. and a humidity equal to or lower than 65%. To maintain a suitable working environment, the air supply rate of the 100.000 \-level clean room is equal to or greater than 40 m.sup.3h/, and the air change rate of air-conditioners is equal to or greater than 15 times/h.

[0057] The water content, cleaning solvent content, warp tensile strength, weft tension strength, pore size, and weight of the polyglycollide warp-knitted support meshes in Examples 1-3 and Contrastive example 1 were tested, and the test results are shown in Table 1.

TABLE-US-00001 Test results Serial number Test items Example 1 Example 2 Example 3 Contrastive example 1 Before drying After drying Before drying After drying Before drying After drying Before drying After drying 1 Tensile strength (MPa) Weft 800 800 861 861 752 752 800 640 Warp 1300 1380 1257 1267 1420 1453 1300 1040 2 Weight (g/m2) 30 30 28 28 25 25 30 29 3 Pore size (.Math.m) 800 800 700 700 1000 1000 800 800 4 Water content (%) 6.71 0 4.98 0 5.34 0 6.71 2.14 5 Cleaning solvent content (%) 0.67 0 0.34 0 0.45 0 0.67 0

[0058] Note: the weight of the polyglycollide warp-knitted support meshes was detected as stipulated in the FZ/T70010-2006 Standard, the water content of the polyglycollide warp-knitted support meshes was detected as stipulated in Appendix C in the YY1116-2010 Standard, the tensile strength and pore size were detected according to the Q/FJHXY 002-2021 Standard, and the cleaning solvent content was detected through a chemical titration method.

[0059] The basic principle, main features, and advantages of the invention are illustrated and described above. Those skilled in the art would appreciate that the invention is not limited to the above examples, and the examples and the description in this specification are merely used to explain the principle of the invention. Various transformations and improvements may be made to the invention without departing from the spirit and scope of the invention, and all these transformations and improvements should fall within the protection scope of the invention. The protection scope of the invention should be defined by the appended claims and their equivalents.