A multilayer composite polycaprolactone plate and a preparation method and application thereof

Abstract

The application discloses a kind of multilayer composite polycaprolactone plate, including dense skin layer and foamed core layer between dense skin layer;Wherein, the dense skin layer includes component: PCL resin 100 parts;Filler 5-10 parts;Crosslinking agent 0.5-3 parts;Auxiliary agent 0-1.5 parts;The foamed core layer includes component: PCL resin 100 parts;Crosslinking agent 4-9 parts;Foaming agent 7-13 parts.The application is prepared by multilayer co-extrusion and the two sides are dense PCL skin layer, the middle layer is chemical foaming PCL core layer Multilayer composite polycaprolactone plate, realizes the lightweight requirement of PCL plate, while guaranteeing the mechanical strength and bending performance of plate, solve the technical problems that functional PCL plate in prior art is difficult to simultaneously consider high strength, high toughness and lightweight;Exempt from punching weight reduction process link after plate forming in preparation process, realize the continuous forming of lightweight PCL plate, greatly improve production efficiency, reduce processing cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer material production, in particular to a multi-layer composite polycaprolactone plate and a preparation method and application thereof. BACKGROUND

[0002] Polycaprolactone (PCL) is a new type of degradable high polymer material, which is widely used in various fields of national economy due to its good biocompatibility, biodegradability, and compatibility with other polymers, and has great application value in the biomedical field (such as drug delivery, surgical suture, porous tissue engineering scaffold, etc.).

[0003] Due to the low melting point, low melt strength and slow crystallization speed of PCL, sagging phenomenon easily occurs during extrusion, resulting in low yield of PCL plate. At present, in order to improve the crystallization speed of PCL, the commonly used methods include adding inorganic powder (such as Chinese patent applications CN201611002871.2, CN201210325614.8, etc.) or adding nano-cellulose and other organic matters (such as Chinese patents CN201710420928.9, CN201710583952.4, etc.), which can obviously accelerate the crystallization of PCL through typical heterogeneous nucleation, and can improve the half-crystallization time to within 1 minute; in order to improve the melt strength of PCL, radiation crosslinking and chemical crosslinking methods are usually combined (such as patents CN202010435708.5, CN202110929886.8). With the application of the above methods, the processing stability of PCL plate is improved.

[0004] However, for medical plates, excellent strength and bending performance are required, and at the same time, lightweight is required, and at present, punching weight reduction treatment is usually carried out after plate forming, but this method will greatly affect the strength and toughness of the plate, and the production efficiency is low and the production cost is high. To obtain a functional PCL plate with high strength, high toughness and lightweight coexisting is still an important problem that needs to be solved in the current industrial development. SUMMARY

[0005] In order to overcome the deficiencies of the prior art, the purpose of the present application is to provide a multi-layer composite polycaprolactone plate which takes into account high strength, high toughness and lightweight.

[0006] Another purpose of the present application is to provide a preparation method of a multi-layer composite polycaprolactone plate.

[0007] The present application is achieved by the following technical solutions:

[0008] A multi-layer composite polycaprolactone plate, characterized in that it comprises dense skin layers 1, 3 and a foamed core layer 2 located between the dense skin layers;

[0009] The dense skin layer (1, 3) comprises the following components by weight fraction:

[0010] PCL resin 100 parts;

[0011] Filler 5-10 parts;

[0012] Crosslinking agent 0.5-3 parts;

[0013] Auxiliary agent 0-1.5 parts;

[0014] The foamed core layer (2) comprises the following components by weight fraction:

[0015] PCL resin 100 parts;

[0016] Crosslinking agent 4-9 parts;

[0017] Foaming agent 7-13 parts.

[0018] Preferably, the PCL resin has a melt index of 0.1-10 g / 10 min, preferably 2-5 g / 10 min, at 190℃, 2.16 kg.

[0019] Preferably, the filler is selected from any one or several of calcium carbonate, talc or kaolin; further preferably, the filler is 1000-6000 mesh, more preferably 3000-4000 mesh.

[0020] Preferably, the crosslinking agent is selected from one or more of trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, triallyl isocyanurate, ethylene dimethacrylate, pentaerythritol triacrylate or butanediol dimethacrylate; further preferably, the crosslinking agent is selected from one or more of trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, triallyl isocyanurate, pentaerythritol triacrylate or butanediol dimethacrylate.

[0021] Preferably, the foaming agent is a mixture of foaming agent I and foaming agent II in a weight ratio of (0.4-1.5):1, wherein the foaming agent I is selected from any one or several of sodium carbonate, sodium bicarbonate or ammonium carbonate, and the foaming agent II is selected from an azo foaming agent; more preferably, the foaming agent is a mixture of foaming agent I and foaming agent II in a weight ratio of (0.5-0.9):1.

[0022] The azo foaming agent can be selected from any one or several of diazo amino benzene, azo dicarboxamide or azo diisobutyronitrile.

[0023] Preferably, the auxiliary agent includes an ultraviolet absorber or an antioxidant.

[0024] As a preferred embodiment, the ultraviolet absorber is 0.3-0.5 parts, and the antioxidant is 0.5-1 part.

[0025] The ultraviolet absorber can be selected from any one or several of UV-9, UV-531, UV-24 or MS-40.

[0026] The antioxidant is selected from any one or several of antioxidant 1010 or antioxidant 168.

[0027] The multilayer composite polycaprolactone plate of the present application has a thickness of 150-380 microns, wherein the skin layer has a thickness of ≤20 microns.

[0028] The present application also provides a preparation method of the multilayer composite polycaprolactone plate, comprising the following steps:

[0029] (1) Preparation of PCL modified resin I: according to the component ratio of the dense skin layer, the components are uniformly stirred in a high-speed stirrer, then added to a twin-screw extruder, extruded and granulated to prepare PCL modified resin I;

[0030] (2) Preparation of PCL modified resin II: according to the component ratio of the foaming core layer, the components are uniformly stirred in a high-speed stirrer, then added to a twin-screw extruder, extruded and granulated to prepare PCL modified resin II;

[0031] (3) PCL modified resin I is added to single-screw extruder I 4 and single-screw extruder III 6 respectively, and PCL modified resin II is added to single-screw extruder II 5. The PCL melt in the three single-screw extruders is laminated in the die 7 by in-mold mixing method, then extruded through the setting roller I 8 and the setting roller II 9, cut and rolled after passing through the annealing furnace 10 to prepare the multilayer composite polycaprolactone plate.

[0032] The present application can obtain a multilayer composite polycaprolactone plate with a required thickness by controlling the extrusion speed of single-screw extruder I, single-screw extruder II and single-screw extruder III.

[0033] Preferably, the length-diameter ratio of the twin-screw extruder in steps (1) and (2) is 32-40, and the die temperature is set to 155-175 ℃.

[0034] Preferably, in step (3), the temperature of single-screw extruder I 4 and single-screw extruder III 6 is set to 70-130 ℃, and the temperature of single-screw extruder II 5 is set to 70-150 ℃.

[0035] As a preferred embodiment, the temperature of the single-screw extruder I 4 and the single-screw extruder III 6 is set to zone 1 70℃, zone 2 100℃, zone 3 140℃, zone 4 130℃, zone 5 130℃; the temperature of the single-screw extruder II 5 is set to zone 1 70℃, zone 2 120℃, zone 3 140℃, zone 4 150℃, zone 5 150℃; and the temperature of the die 7 is set to 150℃.

[0036] Preferably, the setting roll I 8 and the setting roll II 9 are continuous parallel arranged counter-rollers, wherein the distance between the setting roll I 8 and the die 7 is ≤10 cm, and the temperature of the setting roll I 8 is set to 45-55℃, and the temperature of the setting roll II 9 is set to 40-50℃. The setting roll I is used for stabilizing the PCL melt extrusion crystallization, and the setting roll II is used for annealing to release internal stress.

[0037] After passing through the setting roll, the plate is subjected to an annealing furnace to keep the structure of the plate stable. Preferably, the temperature of the annealing furnace 10 is set to 40-55℃, and the plate is subjected to the annealing furnace 10 for 30-100 seconds.

[0038] The application also provides the use of the above-mentioned multilayer composite polycaprolactone plate in the field of biological medicine, which can be specifically used for medical plates, such as medical shaping plates, etc.

[0039] The application has the following beneficial effects:

[0040] The multilayer composite polycaprolactone plate of the application has a dense PCL skin layer on both sides and a chemically foamed PCL core layer in the middle, which realizes the lightweight requirement of the PCL plate and guarantees the mechanical strength and bending performance of the plate, and solves the technical problem that the functional PCL plate in the prior art is difficult to simultaneously have high strength, high toughness and lightweight.

[0041] The multilayer composite polycaprolactone plate is prepared by multilayer co-extrusion, which eliminates the process step of punching and reducing weight of the PCL medical plate after molding in the prior art, realizes the continuous molding of the lightweight PCL plate, and greatly improves the production efficiency and reduces the processing cost. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 FIG. 1 is a structural schematic diagram of a multilayer composite polycaprolactone plate according to the application;

[0043] Figure 2 FIG. 4 is a partial structural schematic diagram of a preparation device for a multilayer composite polycaprolactone plate according to the application.

[0044] Figure 3 FIG. 5 is a structural schematic diagram of an extruded multilayer composite polycaprolactone plate in the preparation process of a multilayer composite polycaprolactone plate according to the application.

[0045] Reference numerals: 1, 3-dense skin layer, 2-foamed core layer, 4-single screw extruder I, 5-single screw extruder II, 6-single screw extruder III, 7-die, 8-shaping roller I, 9-shaping roller II, 10-annealing furnace. Embodiment

[0046] The application will be described in detail below with specific examples. The following examples will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made. These all belong to the protection scope of the application.

[0047] The reagents and raw materials used in the examples and comparative examples of the application are all commercially available.

[0048] Example 1

[0049] (1) Preparation of PCL modified resin I: 100 parts of PCL resin (melt index of 2 g / 10 min at 190℃, 2.16 kg), 10 parts of calcium carbonate (3000 mesh), 3 parts of butanediol dimethacrylate, 0.3 parts of UV-531, 1 part of antioxidant (antioxidant 1010 and antioxidant 168 compounded in a weight ratio of 1:1) were uniformly stirred in a high-speed stirrer, then added to a twin-screw extruder, extruded and granulated to prepare PCL modified resin I; wherein the length-diameter ratio of the twin-screw extruder is 36, the extruder die temperature is 160℃, the screw 1 zone temperature is 100℃, and the other temperature zones are set in turn.

[0050] (2) Preparation of PCL modified resin II: 100 parts of PCL resin (melt index of 2 g / 10 min at 190℃, 2.16 kg), 4 parts of trimethylolpropane trimethacrylate, 3 parts of sodium carbonate, 7 parts of diazo amino benzene were uniformly stirred in a high-speed stirrer, then added to a twin-screw extruder, extruded and granulated to prepare PCL modified resin II; wherein the length-diameter ratio of the twin-screw extruder is 36, the extruder die temperature is 160℃, the screw 1 zone temperature is 100℃, and the other temperature zones are set in turn.

[0051] (3) The PCL modified resin I is added into single screw extruder I 4 and single screw extruder III 6 respectively, and the PCL modified resin II is added into single screw extruder II 5; wherein, the temperature of single screw extruder I and single screw extruder III is set as zone 1 70℃, zone 2 100℃, zone 3 140℃, zone 4 130℃, zone 5 130℃, and the rotating speed is set as 60 rpm; the temperature of single screw extruder II is set as zone 1 70℃, zone 2 120℃, zone 3 140℃, zone 4 150℃, zone 5 150℃, and the rotating speed is set as 160 rpm; the temperature of die 7 is set as 150℃; the PCL melt in the three single screw extruders is adhered in the die by in-die mixing method, foaming in the middle layer after extrusion, passing through the setting roller I 8 which is 8 centimeters away from the die 8, then passing through the setting roller II 9, and cutting and rolling after the annealing furnace 10, to obtain the multi-layer composite polycaprolactone plate, and the thickness of the plate is 180 microns, wherein the thickness of the skin layer is 10 microns.

[0052] Example 2:

[0053] (1) Preparation of PCL modified resin I: 100 parts of PCL resin (melt index is 2.8 g / 10 min under the condition of 190℃, 2.16 kg), 8 parts of talc (3500 mesh), 1 part of pentaerythritol triacrylate, 0.3 parts of UV-9, and 1 part of antioxidant (antioxidant 1010 and antioxidant 168 are compounded in a weight ratio of 1:1) are uniformly stirred in a high-speed stirrer, and then added into a twin-screw extruder to be extruded and granulated to obtain PCL modified resin I; wherein, the length-diameter ratio of the twin-screw extruder is 36, the die temperature of the extruder is 160℃, the temperature of screw zone 1 is 100℃, and the temperatures of other zones are set to increase successively.

[0054] (2) Preparation of PCL modified resin II: 100 parts of PCL resin (melt index is 2.8 g / 10 min under the condition of 190℃, 2.16 kg), 4 parts of trimethylacrylate, 3 parts of sodium bicarbonate, and 5 parts of azobisformamide are uniformly stirred in a high-speed stirrer, and then added into a twin-screw extruder to be extruded and granulated to obtain PCL modified resin II; wherein, the length-diameter ratio of the twin-screw extruder is 36, the die temperature of the extruder is 160℃, the temperature of screw zone 1 is 100℃, and the temperatures of other zones are set to increase successively.

[0055] (3) PCL modified resin I is added into single screw extruder I 4 and single screw extruder III 6 respectively, and PCL modified resin II is added into single screw extruder II 5; wherein, the temperature of single screw extruder I and single screw extruder III is set as zone 1 70℃, zone 2 100℃, zone 3 140℃, zone 4 130℃, zone 5 130℃, and the rotating speed is set as 80 rpm; the temperature of single screw extruder II is set as zone 1 70℃, zone 2 120℃, zone 3 140℃, zone 4 150℃, zone 5 150℃, and the rotating speed is set as 400 rpm; the temperature of die 7 is set as 150℃; the PCL melt in the three single screw extruders is adhered in the die by in-die mixing method, foaming in the middle layer after extrusion, passing through a distance of 5 cm from the die to shaping roller I 8, then passing through shaping roller II 9, and cutting and rolling after annealing furnace 10, to obtain a multi-layer composite polycaprolactone plate, and the thickness of the plate is 350 microns, wherein the skin layer thickness is 20 microns.

[0056] Example 3:

[0057] (1) Preparation of PCL modified resin I: 100 parts of PCL resin (melt index is 5 g / 10 min under the condition of 190℃, 2.16 kg), 10 parts of kaolin (4000 mesh), 3 parts of trimethyl acrylate, 0.3 parts of UV-24, and 1 part of antioxidant (antioxidant 1010 and antioxidant 168 are compounded in a weight ratio of 1:1) are uniformly stirred in a high-speed stirrer, and then added into a twin-screw extruder to be extruded and granulated to prepare PCL modified resin I; wherein, the length-diameter ratio of the twin-screw extruder is 36, the extruder die temperature is 160℃, the screw zone 1 temperature is 100℃, and the other temperature zones are set to increase successively.

[0058] (2) Preparation of PCL modified resin II: 100 parts of PCL resin (melt index is 5 g / 10 min under the condition of 190℃, 2.16 kg), 8 parts of trimethylolpropane trimethyl acrylate, 5 parts of ammonium carbonate, and 7 parts of azobisisobutyronitrile are uniformly stirred in a high-speed stirrer, and then added into a twin-screw extruder to be extruded and granulated to prepare PCL modified resin II; wherein, the length-diameter ratio of the twin-screw extruder is 36, the extruder die temperature is 160℃, the screw zone 1 temperature is 100℃, and the other temperature zones are set to increase successively.

[0059] (3) The PCL modified resin I is added into single screw extruder I 4 and single screw extruder III 6 respectively, and the PCL modified resin II is added into single screw extruder II 5; wherein, the temperature of single screw extruder I and single screw extruder III is set as zone 1 70℃, zone 2 100℃, zone 3 140℃, zone 4 130℃, zone 5 130℃, and the rotating speed is set as 80 rpm; the temperature of single screw extruder II is set as zone 1 70℃, zone 2 120℃, zone 3 140℃, zone 4 150℃, zone 5 150℃, and the rotating speed is set as 240 rpm; the temperature of die 7 is set as 150℃; the PCL melt in the three single screw extruders is adhered in the die by in-die mixing method, foaming in the middle layer after extrusion, passing through the setting roller I 8 which is 8 centimeters away from the die, then passing through the setting roller II 9, and cutting and rolling after the annealing furnace 10, to obtain the multi-layer composite polycaprolactone plate, and the thickness of the plate is 230 microns, wherein, the thickness of the skin layer is 15 microns.

[0060] Example 4:

[0061] (1) Preparation of PCL modified resin I: 100 parts of PCL resin (melt index is 2 g / 10 min under the condition of 190℃, 2.16 kg), 5 parts of calcium carbonate (3000 mesh), 2 parts of butanediol dimethacrylate, 0.5 parts of MS-40, and 1 part of antioxidant (antioxidant 1010 and antioxidant 168 are compounded in a weight ratio of 1:1) are uniformly stirred in a high-speed stirrer, and then added into a twin-screw extruder to be extruded and granulated to prepare PCL modified resin I; wherein, the length-diameter ratio of the twin-screw extruder is 36, the extruder die temperature is 160℃, the screw zone 1 temperature is 100℃, and the other temperature zones are set in turn.

[0062] (2) Preparation of PCL modified resin II: 100 parts of PCL resin (melt index is 2 g / 10 min under the condition of 190℃, 2.16 kg), 6 parts of triallyl isocyanurate, 4 parts of sodium carbonate, and 6 parts of diazo amino benzene are uniformly stirred in a high-speed stirrer, and then added into a twin-screw extruder to be extruded and granulated to prepare PCL modified resin II; wherein, the length-diameter ratio of the twin-screw extruder is 36, the extruder die temperature is 160℃, the screw zone 1 temperature is 100℃, and the other temperature zones are set in turn.

[0063] (3) PCL modified resin I was added into single screw extruder I 4 and single screw extruder III 6, and PCL modified resin II was added into single screw extruder II 5; wherein, the temperature of single screw extruder I and single screw extruder III was set as zone 1 70℃, zone 2 100℃, zone 3 140℃, zone 4 130℃, zone 5 130℃, and the rotating speed was set as 60 rpm; the temperature of single screw extruder II was set as zone 1 70℃, zone 2 120℃, zone 3 140℃, zone 4 150℃, zone 5 150℃, and the rotating speed was set as 300 rpm; the temperature of die 7 was set as 150℃; the PCL melt in the three single screw extruders was adhered in the die by in-die mixing method, and the middle layer was foamed after extrusion, then passed through a distance of 8 cm from the die 8 to the shaping roller I 8, then passed through the shaping roller II 9, and after the annealing furnace 10, it was cut and rolled to obtain the multi-layer composite polycaprolactone plate, and the thickness of the plate was 300 microns, wherein the thickness of the skin layer was 16 microns.

[0064] Example 5:

[0065] The difference from example 3 is that in step (3), the rotating speed of single screw extruder I and single screw extruder III was set as 95 rpm, and the rotating speed of single screw extruder II was set as 230 rpm.

[0066] The multi-layer composite polycaprolactone plate was prepared, and the thickness of the plate was 230 microns, wherein the thickness of the skin layer was 45 microns.

[0067] Example 6:

[0068] The difference from example 3 is that in step (3), the rotating speed of single screw extruder I and single screw extruder III was set as 60 rpm, and the rotating speed of single screw extruder II was set as 130 rpm.

[0069] The multi-layer composite polycaprolactone plate was prepared, and the thickness of the plate was 140 microns, wherein the thickness of the skin layer was 15 microns.

[0070] Example 7:

[0071] The difference from example 3 is that in step (3), the rotating speed of single screw extruder I and single screw extruder III was set as 100 rpm, and the rotating speed of single screw extruder II was set as 460 rpm.

[0072] The multi-layer composite polycaprolactone plate was prepared, and the thickness of the plate was 400 microns, wherein the thickness of the skin layer was 15 microns.

[0073] Example 8:

[0074] The difference from example 3 is that in step (1), 1000 mesh kaolin was used in the preparation of PCL modified resin I.

[0075] Example 9:

[0076] The difference from Example 3 is that the PCL modified resin I in step (1) is prepared by using 6000 mesh kaolin.

[0077] Example 10:

[0078] The difference from Example 3 is that the PCL modified resin I in step (1) and the PCL modified resin II in step (2) are prepared by using PCL resin with a melt index of 10 g / 10 min at 190℃, 2.16 kg.

[0079] Example 11:

[0080] The difference from Example 3 is that the PCL modified resin II in step (2) is prepared by adding 3.5 parts of ammonium carbonate and 8.5 parts of azobisisobutyronitrile.

[0081] Example 12:

[0082] The difference from Example 3 is that the PCL modified resin II in step (2) is prepared by adding 7 parts of ammonium carbonate and 5 parts of azobisisobutyronitrile.

[0083] Comparative Example 1:

[0084] The difference from Example 3 is that the component formula of the PCL modified resin II in step (2) is 100 parts of PCL resin, 8 parts of trimethylolpropane trimethacrylate, and 12 parts of ammonium carbonate.

[0085] A multi-layer composite polycaprolactone plate is prepared, and the plate has a thickness of 230 microns, wherein the skin layer has a thickness of 15 microns.

[0086] Comparative Example 2:

[0087] The difference from Example 3 is that the component formula of the PCL modified resin II in step (2) is 100 parts of PCL resin, 8 parts of trimethylolpropane trimethacrylate, and 12 parts of azobisisobutyronitrile.

[0088] A multi-layer composite polycaprolactone plate is prepared, and the plate has a thickness of 230 microns, wherein the skin layer has a thickness of 15 microns.

[0089] Comparative Example 3:

[0090] Preparation of PCL modified resin I: 100 parts of PCL resin (melt index 5 g / 10 min), 10 parts of kaolin (4000 mesh), 3 parts of trimethyl methacrylate tricarboxymethyl propyl, 0.3 parts of UV-24, 1 part of antioxidant (antioxidant 1010 and antioxidant 168 are compounded in a weight ratio of 1:1) are stirred uniformly in a high-speed mixer, then added to a twin-screw extruder, extruded and granulated to prepare PCL modified resin I; wherein the length-diameter ratio of the twin-screw extruder is 36, the extruder die temperature is 160°C, the screw 1 zone temperature is 100°C, and the other temperature zones are set to increase successively.

[0091] The PCL modified resin I is added to a single-screw extruder, wherein the temperature of the single-screw extruder is set to zone 1 70°C, zone 2 100°C, zone 3 140°C, zone 4 130°C, and zone 5 130°C, and the die temperature is set to 150°C; extruded, shaped, annealed, cut and rolled to prepare a polycaprolactone plate with a thickness of 230 microns.

[0092] Comparative Example 4:

[0093] Preparation of PCL modified resin II: 100 parts of PCL resin (melt index 5 g / 10 min), 8 parts of trimethylolpropane trimethacrylate, 5 parts of ammonium carbonate, and 7 parts of azobisisobutyronitrile are stirred uniformly in a high-speed mixer, then added to a twin-screw extruder, extruded and granulated to prepare PCL modified resin II; wherein the length-diameter ratio of the twin-screw extruder is 36, the extruder die temperature is 160°C, the screw 1 zone temperature is 100°C, and the other temperature zones are set to increase successively.

[0094] The PCL modified resin II is added to a single-screw extruder, wherein the temperature of the single-screw extruder is set to zone 1 70°C, zone 2 120°C, zone 3 140°C, zone 4 150°C, and zone 5 150°C, and the die temperature is set to 150°C; extruded, shaped, annealed, cut and rolled to prepare a polycaprolactone plate with a thickness of 230 microns, which has a rough surface and cannot meet the use of medical plates.

[0095] Related performance tests:

[0096] (1) Density: tested according to GB / T 17794-2008;

[0097] (2) Tensile strength: tested according to GB / T 6344-2008;

[0098] (3) Bending strength: tested according to GB / T8812.1-2007;

[0099] (4) Elongation at break: tested according to GB / T 6344-2008.

[0100] Table 1: Results of relevant performance tests of Examples 1-12 and Comparative Examples 1-4

[0101]

[0102] As can be seen from the results of the above examples, the multi-layer composite polycaprolactone plate with a dense PCL skin layer and a chemically foamed PCL core layer in the middle layer is prepared by multi-layer co-extrusion, and the lightweight requirement of the PCL plate (the density of the plate ≤0.82 g / cm 3 ) can be achieved without the process of punching and weight reduction, while the mechanical strength and bending performance of the plate are ensured, and high strength, high toughness and lightweight can be simultaneously considered, meeting the use requirements of medical plates.

[0103] Comparative Examples 1 / 2 and Example 3, the foaming agent is only ammonium carbonate or azobisisobutyronitrile, the foaming effect is poor, the plate density is large, and the lightweight requirement of the medical plate cannot be met.

[0104] Comparative Example 3, a single-layer PCL plate is prepared by using PCL modified resin I, the plate density is large, and the lightweight requirement of the medical plate cannot be met.

[0105] Comparative Example 4, a single-layer PCL plate is prepared by using PCL modified resin II, the surface is rough, and the use of the medical plate cannot be met.

Claims

1. A multilayer composite polycaprolactone sheet, characterized in that, It includes a dense skin layer (1, 3) and a foamed core layer (2) located between the dense skin layers. The dense dermis (1, 3), by weight, comprises the following components: 100 parts of PCL resin; 5-10 parts of filler; Crosslinking agent 0.5-3 parts; 0-1.5 parts of auxiliary agent; The foamed core layer (2) comprises, by weight, the following components: 100 parts of PCL resin; 4-9 parts of crosslinking agent; 7-13 parts of foaming agent; The foaming agent is a mixture of foaming agent I and foaming agent II in a weight ratio of (0.4-1.5):1, wherein foaming agent I is selected from any one or more of sodium carbonate, sodium bicarbonate or ammonium carbonate, and foaming agent II is selected from azo foaming agents.

2. The multilayer composite polycaprolactone sheet according to claim 1, characterized in that, The melt flow index of the PCL resin at 190℃ and 2.16kg is 0.1-10 g / 10min.

3. The multilayer composite polycaprolactone sheet according to claim 2, characterized in that, The melt index of the PCL resin at 190℃ and 2.16kg is 2-5 g / 10min.

4. The multilayer composite polycaprolactone sheet according to claim 1, characterized in that, The filler is selected from any one or more of calcium carbonate, talc, or kaolin.

5. The multilayer composite polycaprolactone sheet according to claim 4, characterized in that, The filler is 1000-6000 mesh.

6. The multilayer composite polycaprolactone sheet according to claim 5, characterized in that, The filler is 3000-4000 mesh.

7. The multilayer composite polycaprolactone sheet according to claim 1, characterized in that, The crosslinking agent is selected from one or more of the following: tricarboxymethyl propyl trimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, triallyl isocyanurate, ethylene dimethacrylate, pentaerythritol triacrylate, or butanediol dimethacrylate.

8. The multilayer composite polycaprolactone sheet according to claim 1, characterized in that, The foaming agent is a mixture of foaming agent I and foaming agent II in a weight ratio of (0.5-0.9):1; the azo foaming agent is selected from any one or more of diazoaminobenzene, azodicarbonamide or azobisisobutyronitrile.

9. The multilayer composite polycaprolactone sheet according to claim 1, characterized in that, The additives include ultraviolet absorbers or antioxidants.

10. The multilayer composite polycaprolactone sheet according to claim 9, characterized in that, The ultraviolet absorber is 0.3-0.5 parts, and the antioxidant is 0.5-1 parts; the ultraviolet absorber is selected from any one or more of UV-9, UV-531, UV-24 or MS-40; the antioxidant is selected from any one or more of antioxidant 1010 or antioxidant 168.

11. The multilayer composite polycaprolactone sheet according to claim 1, characterized in that, The thickness of the sheet material is 150-380 micrometers, of which the skin layer thickness is ≤20 micrometers.

12. The method for preparing multilayer composite polycaprolactone sheets according to any one of claims 1-11, characterized in that, Includes the following steps: (1) Preparation of PCL modified resin I: According to the composition ratio of the dense skin layer, the components were mixed evenly in a high-speed mixer, then added to a twin-screw extruder, extruded and granulated to obtain PCL modified resin I. (2) Preparation of PCL modified resin II: According to the component ratio of the foamed core layer, the components are mixed evenly in a high-speed mixer, then added to a twin-screw extruder, extruded and granulated to obtain PCL modified resin II. (3) PCL modified resin I is added to single screw extruder I (4) and single screw extruder III (6) respectively, and PCL modified resin II is added to single screw extruder II (5). The PCL melt in the three single screw extruders is bonded in the die head (7) by in-die mixing. After extrusion, it passes through shaping roller I (8) and shaping roller II (9), and after passing through the annealing furnace (10), it is cut and rolled up to produce multilayer composite polycaprolactone sheet.

13. The method for preparing multilayer composite polycaprolactone sheets according to claim 12, characterized in that, The temperatures of the single-screw extruder I (4) and single-screw extruder III (6) are set to 70-130℃; the temperature of the single-screw extruder II (5) is set to 70-150℃; the shaping rollers I (8) and shaping rollers II (9) are continuously parallel pressure rollers, wherein the distance between shaping roller I (8) and die head (7) is ≤10 cm and the temperature is set to 45-55℃, and the temperature of shaping roller II (9) is set to 40-50℃; the temperature of the annealing furnace (10) is set to 40-55℃, and the time for the sheet to pass through the annealing furnace (10) is 30-100 seconds.

14. The application of the multilayer composite polycaprolactone sheet according to any one of claims 1-11 in the biomedical field.

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