A method and system for preparing a roller microneedle

Abstract

The application relates to the technical field of needle roller preparation, in particular to a preparation method and system of a roller micro-needle, which comprises the following steps: obtaining a precursor prepared from a carbon-based polymer, the precursor comprising: a plurality of first supports and a plurality of second supports arranged at intervals, the first supports and the second supports intersecting to form a plurality of grid holes arranged at intervals, and a plurality of micro-needles or micro-needle-like structures arranged on at least one support; and performing concentrated heat preservation treatment on the precursor, which comprises the following steps: in a first heating stage, selecting a stress relief temperature to perform heat preservation treatment on the precursor, so as to relieve the stress of the precursor; increasing the temperature to enter a second heating stage, and in the second heating stage, selecting a pyrolysis carbonization temperature to perform heat preservation treatment on the precursor again, so that the precursor is subjected to pyrolysis carbonization, and then the temperature is rapidly increased to a target temperature. The concentrated heat preservation treatment can effectively reduce defects such as foaming, deformation and crushing of the needle roller product.

Description

[0001] Priority application

[0002] This application claims priority to Chinese invention patent application CN2023117246296, filed on December 14, 2023, entitled "A roller microneedle and its preparation method", which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to the field of glassy carbon preparation, specifically to a method and system for preparing roller microneedles. Background Technology

[0004] Microneedles are finely structured, micron-sized needles manufactured using microfabrication technology, allowing for minimally invasive and painless punctures of the skin without touching blood vessels or nerves. Currently, microneedles are used in disease treatment and prevention...

[0005] Microneedling has broad application prospects in fields such as prevention, diagnosis, and cosmetic dermatology. Common microneedling applications fall into two categories:

[0006] I. Microneedle Patches

[0007] Microneedle patches consist of multiple tiny needle tips connected in an array on a base, and have wide applications in disease prevention, diagnosis, rehabilitation, and medical aesthetics.

[0008] Glassy carbon (also known as glassy carbon) is a type of amorphous carbon with good mechanical properties, electrical conductivity, biocompatibility, and chemical stability. Compared with commonly used materials such as polymers, metals, and ceramics for preparing microneedle patches, it has some unique properties. Glassy carbon-based microneedle patches have unique applications in the fields of medicine, electronics, and chemical engineering, and the development of glassy carbon-based microneedle patches is of great significance.

[0009] Glassy carbon is typically produced by gradient pyrolysis of polymeric precursors. This process is complex, and significant volume shrinkage occurs during pyrolysis, leading to substantial product defects such as denaturation, foaming, cracking, and breakage. Developing high-quality glassy carbon microneedle patches presents considerable challenges. For example, CN109627003A discloses a method for preparing novel glassy carbon materials using furfural-furfuryl alcohol modified resin. Another example is CN105819859A, which discloses a method for preparing glassy carbon materials based on polymeric prepolymer precursors. However, these processes suffer from two main drawbacks: firstly, the heating procedures are relatively complex, requiring frequent and repeated temperature holding at various points (leading to multi-stage temperature control, resulting in higher implementation costs and greater monitoring difficulties), and the process is relatively time-consuming; secondly, it is extremely difficult to avoid significant product defects during the preparation of glassy carbon microneedles, which severely affects the morphology and properties of the glassy carbon.

[0010] Currently, research has achieved the fabrication of glassy carbon microneedles; however, microneedles often need to be fabricated into microneedle patches for convenient use and to exert their effects, especially since the conductivity and other functions of glassy carbon microneedles are highly dependent on the performance of the microneedle substrate. However, due to the fine and complex structure of microneedle patches, the pyrolysis process in glassy carbon fabrication can lead to severe deformation defects in conventional microneedle patches, posing a significant challenge to the development of high-quality glassy carbon microneedle patches.

[0011] II. Roller Microneedle

[0012] Roller microneedles are a type of microneedle-based medical device. They consist of multiple micron-sized needle tips connected in an array on a rotating roller. By rolling, they pierce the skin, forming tiny channels and increasing the skin's transdermal absorption capacity.

[0013] Currently, roller microneedles are mainly made of metal materials, such as stainless steel, which have good mechanical properties, but their preparation is relatively complex and costly, making it difficult to apply on a large scale.

[0014] Therefore, developing novel roller microneedle products and their preparation methods is of great significance and application value. Currently, there is an urgent need for a preparation method that can improve the morphology, performance, and other properties of microneedle products while controlling implementation costs. Summary of the Invention

[0015] The purpose of this invention is to provide a method and system for preparing roller microneedles, which partially solves or alleviates the above-mentioned deficiencies in the prior art, improves the preparation quality of microneedle patches, and reduces preparation costs.

[0016] To solve the aforementioned technical problems, the present invention specifically adopts the following technical solution: a method for preparing roller microneedles, comprising:

[0017] S401 Obtain a precursor prepared from a carbon-based polymer, the precursor comprising: a plurality of first supports and a plurality of second supports arranged at intervals, the first and second supports intersecting to form a plurality of mesh pores at intervals, and at least one support having a plurality of microneedles or microneedle-like structures disposed thereon;

[0018] S402 performs centralized heat preservation treatment on the precursor; wherein, S402 includes the following steps:

[0019] During the first heating stage, the precursor is subjected to heat preservation treatment at a stress relief temperature to relieve stress in the precursor; wherein, the stress relief temperature is selected by a first selection rule;

[0020] The temperature is increased to enter the second heating stage, and the precursor is kept at a pyrolysis carbonization temperature again during the second heating stage so that the precursor undergoes pyrolysis carbonization. At this time, the precursor shrinks and deforms during the pyrolysis carbonization process. The pyrolysis carbonization temperature is selected by a second selection rule.

[0021] The first selection rule is: to select the stress relief temperature from the weight loss rate fluctuation temperature;

[0022] The weight loss rate fluctuation temperature corresponds to one or more temperature values ​​corresponding to at least one curve segment with the largest curvature change in the thermogravimetric differential curve, and the thermogravimetric differential curve is a curve representing the rate of weight change with temperature; the second selection rule is: select the pyrolysis temperature from the weight loss fluctuation temperature; wherein, the weight loss fluctuation temperature corresponds to one or more temperature values ​​corresponding to one curve segment with the largest curvature change in the thermogravimetric analysis curve within the range where the slope gradually decreases, and the thermogravimetric analysis curve is a curve representing the weight change with temperature.

[0023] In some embodiments, the width of the bracket is less than or equal to 3 mm.

[0024] In some embodiments, prior to S402, the step of immersing the precursor in an alcoholic liquid for a first time is further included: the alcoholic liquid refers to an alcohol solution or an alcohol solvent.

[0025] In some embodiments, the precursor is designed in a columnar shape, wherein a plurality of first supports are arranged in at least one ring around the column, and a plurality of second supports are arranged at intervals along the length direction of the first supports and intersect with the plurality of first supports to form a columnar frame in combination with the first supports; the precursor further includes: a third support and a fourth support disposed inside the columnar frame, wherein the third support and the fourth support are arranged intersectingly in at least two directions, and the two ends of the third support and the fourth support are respectively connected to the first support or the second support to support the columnar frame;

[0026] The first and / or second supports have multiple microneedles or microneedle-like structures on their sides.

[0027] In some embodiments, the length of the first support is less than or equal to 200 mm, and the width of the columnar frame is less than or equal to 100 mm.

[0028] In some embodiments, S402 further includes the step of:

[0029] In the subsequent third heating stage, the temperature is continuously increased from the pyrolysis temperature to the target heating temperature.

[0030] In some embodiments, during the third heating stage, the temperature is increased to a variable-speed temperature point using a first heating rate, and then increased to a target heating temperature using a second heating rate. The second heating rate is greater than the first heating rate, and the variable-speed temperature point is the temperature point corresponding to the point where the slope of the thermogravimetric analysis curve is less than a preset slope threshold as the slope gradually increases.

[0031] In some embodiments, the method further includes:

[0032] During the second heating stage, gas is introduced into the heating chamber containing the precursor.

[0033] In some embodiments, the method further includes:

[0034] During the second heating stage, the concentration of impurities in the precursor during the pyrolysis and carbonization process is collected using the gas; wherein, the impurities include: a first type of impurities, and the first type of impurities includes one or more of the following: carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, and nitrogen.

[0035] When the pyrolysis temperature reaches the first set time but does not reach the second duration T2, and the first concentration index is within the first concentration threshold range X1, a first time reduction signal is sent to the heating chamber.

[0036] When the centralized heat preservation method enters the pyrolysis temperature and reaches or exceeds the second duration T2, and the first concentration index belongs to the corresponding second concentration threshold range X2, a first delay signal is sent to the heating box; wherein, the second duration is the preset pyrolysis heat preservation treatment duration.

[0037] The present invention also provides a system for preparing roller microneedles, comprising:

[0038] The centralized insulation module is configured to handle centralized insulation treatment of the precursor; wherein,

[0039] The precursor is obtained by preparing a carbon-based polymer and includes: a plurality of first supports and a plurality of second supports arranged at intervals, wherein the first and second supports intersect to form a plurality of spaced-apart mesh pores.

[0040] At least one support is provided with multiple microneedles or microneedle-like structures; and the centralized insulation module includes:

[0041] The first heating unit is configured to perform a heat preservation treatment on the precursor at a stress relief temperature during a first heating stage, so as to relieve stress in the precursor; wherein the stress relief temperature is selected by a first selection rule.

[0042] The second heating unit is configured to raise the temperature to enter the second heating stage, and to use the pyrolysis carbonization temperature to perform heat preservation treatment on the precursor again during the second heating stage, so that the precursor undergoes pyrolysis carbonization. At this time, the precursor shrinks and deforms during the pyrolysis carbonization process; the pyrolysis carbonization temperature is selected by a second selection rule.

[0043] The first selection rule is: to select the stress relief temperature from the weight loss rate fluctuation temperature;

[0044] The weight loss rate fluctuation temperature corresponds to one or more temperature values ​​corresponding to at least one curve segment with the largest curvature change in the thermogravimetric differential curve, and the thermogravimetric differential curve is a curve representing the rate of weight change with temperature; the second selection rule is: select the pyrolysis temperature from the weight loss fluctuation temperature; wherein, the weight loss fluctuation temperature corresponds to one or more temperature values ​​corresponding to one curve segment with the largest curvature change in the thermogravimetric analysis curve within the range where the slope gradually decreases, and the thermogravimetric analysis curve is a curve representing the weight change with temperature.

[0045] Beneficial technical effects:

[0046] For the preparation of glassy carbon roller needles, this invention proposes a concentrated heat preservation method. This method, by concentrating heat preservation within a lower temperature range (e.g., below the pyrolysis and carbonization temperature), unexpectedly eliminates the dependence on slow heating (e.g., requiring gradient heat preservation throughout the heating process). In other words, this invention proposes a simplified microneedle preparation process.

[0047] Furthermore, this centralized heat preservation method ensures that the needle roller products maintain good morphology and strength properties even when manufacturing larger-sized needle rollers. For example, even when the length of the needle roller precursor is increased to 200 mm and the width (equivalent to the radius) is increased to 100 mm, it can still maintain stable deformation during heating.

[0048] Furthermore, by concentrating the critical heat treatment in the low-temperature range, this invention facilitates the industrial application of the entire preparation method. For example, users can select key heat treatment stages (such as the pyrolysis and carbonization stage) for centralized monitoring and dynamically adjust the operating parameters of the centralized heat treatment method through monitoring. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale. Obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0050] Figure 1 This is a schematic flowchart of a centralized heat preservation method in an exemplary embodiment of the present invention;

[0051] Figure 2a This is a temperature design schematic diagram of a centralized heat preservation method in an exemplary embodiment of the present invention;

[0052] Figure 2b This is a temperature design schematic diagram of a centralized heat preservation method in another exemplary embodiment of the present invention;

[0053] Figure 3 This is a schematic diagram of the thermogravimetric curve of the gridded precursor in an exemplary embodiment of the present invention;

[0054] Figure 4 This is a schematic diagram of the structure of the meshed microneedles in an exemplary embodiment of the present invention;

[0055] Figure 5 This is a schematic diagram of the surface morphology of the gridded precursor after pyrolysis treatment by a centralized heat preservation method in an exemplary embodiment of the present invention;

[0056] Figure 6 This is a schematic diagram of the structure of the gridded precursor in an exemplary embodiment of the present invention;

[0057] Figure 7 A schematic diagram showing the effect of different heating temperatures on the conductivity of meshed microneedles;

[0058] Figure 8 A schematic diagram of a failed product;

[0059] Figure 9 This is a schematic diagram of the monitoring system modules in an exemplary embodiment of the present invention;

[0060] Figure 10 This is a schematic diagram of the structure of the needle roller precursor in an exemplary embodiment of the present invention;

[0061] Figure 11 for Figure 10 The side view of the precursor shown.

[0062] Figure label:

[0063] 01 is the main body, 011 is the micro needle, 012 is the mesh hole, and 02 is the hollow area. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0065] In this document, suffixes such as "module," "part," or "unit" used to denote elements are used only for the purpose of illustrative purposes and have no specific meaning in themselves. Therefore, "module,"

[0066] "Component" or "unit" can be used interchangeably.

[0067] In this document, the terms "upper," "lower," "inner," "outer," "front," "rear," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0068] In this document, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0069] In this document, "and / or" includes any and all combinations of one or more of the listed related items.

[0070] In this article, "multiple" means two or more, that is, it includes two, three, four, five, etc.

[0071] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0072] As used in this specification, the term "about" typically means + / - 5% of the value, more typically + / - 4%, more typically + / - 3%, more typically + / - 2%, even more typically + / - 1%, even more typically + / - 0.5% of the value.

[0073] In this specification, certain embodiments may be disclosed in a range-bound format. It should be understood that this "range-bound" description is merely for convenience and brevity and should not be construed as a rigid limitation on the disclosed range. Therefore, the description of the range should be considered as having specifically disclosed all possible subranges and independent numerical values ​​within those ranges. For example, range The description should be considered as having specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within this range, such as 1, 2, 3, 4, 5, and 6. The above rules apply regardless of the breadth of the range. In this document, a "data point" can refer to a segment of data corresponding to one or more temperature points.

[0074] In this article, the cross-section of the "support" can be one or more of the following structures: circular or near-circular.

[0075] Polygons or polygon-like shapes. Among them, "polygon-like" can refer to complex geometric shapes that are close to circles but irregular in shape, or even ellipses; "polygon-like" can refer to geometric shapes that are similar to polygons but have chamfered corners (such as chamfered triangles). Of course, the support can also be set to other irregular geometric shapes according to production needs.

[0076] Furthermore, depending on the actual application requirements (such as drug delivery conditions), the cross arrangement of the stent can also be set differently. For example, when the main frame of the stent is a cylinder, the stent can be arranged parallel to the horizontal or axial direction of the cylinder, or it can be arranged at an angle in the direction that intersects with its horizontal or axial direction.

[0077] In this article, "carbon-based polymer" usually refers to carbon-rich polymers. For example, it can be a photocurable polymer such as polyurethane or epoxy resin, or it can be a polymer such as acrylonitrile resin, phenolic resin, or polyimide.

[0078] In this document, "concentration index" refers to an index that can be used to characterize the quantity / concentration of a substance (such as an impurity). For example, in some embodiments, the concentration index can be characterized by the impurity flow rate per unit time; or, in other embodiments, the concentration index can also be characterized by the quantity of impurities discharged per unit time; or, in yet another embodiment, the concentration index can also be characterized by the impurity concentration per unit gas.

[0079] In this paper, "mesh material" is also referred to as "mesh precursor," which refers to a material with multiple mesh holes (or openings) distributed on a material plane, and the target to be formed (such as microneedles) is set at the edge of the mesh holes. These mesh holes can be arranged in a regular mesh distribution on the material plane. The preparation method that enables the formation of mesh holes on the precursor is called a mesh preparation method, and the mesh preparation method in this paper is preferably a 3D printing method.

[0080] Glassy carbon materials typically employ a high-temperature sintering process with gradient temperature control throughout the entire process (e.g., a final temperature hold at around 1000°C is often required). In this paper, the "concentrated temperature control process," also known as the low-temperature gradient temperature control process, refers to a relatively concentrated temperature control treatment for key processes (such as stress relief and pyrolysis carbonization) of the meshed material. Furthermore, in this concentrated treatment stage, the temperature control treatment is directly guided by the technical outcome. That is, it directly targets stress relief and pyrolysis carbonization, using targeted temperature control to directly achieve these objectives. This reduces the impact of heating rate on precursor deformation in subsequent heating stages, allowing subsequent heating stages (such as the third heating stage) to reach the target heating temperature quickly without relying on temperature control, thus simplifying the heating process.

[0081] In other words, the centralized insulation method based on gridded precursors provided by this invention differs from the decentralized insulation treatment procedures set in the low-temperature and high-temperature ranges. It directly aims to relieve stress and achieve pyrolysis carbonization, specifically meeting the processing requirements in the low-temperature range through a limited number of insulation treatments (even two or three treatments can achieve the goal). This centralized insulation treatment design in the low-temperature range unexpectedly frees the preparation of glassy carbon from dependence on high-temperature insulation treatments.

[0082] Furthermore, experimental verification has shown that glass carbon products treated with centralized heat preservation methods can still achieve good quality (i.e., defects such as foaming, breakage, and deformation are effectively controlled).

[0083] In this article, such as Figure 2b As shown, the "rapid heating process" refers to a continuous and rapid heating method used in the third heating stage (i.e., after the heat preservation treatment of pyrolysis and carbonization) to complete the final transformation of material properties and prepare high-purity glassy carbon. For example, the rapid heating rate can be greater than or equal to about 0.5℃ / min, and can even reach about 2℃ / min after speed variation.

[0084] Microneedles (MN) are a novel physical penetration enhancement technology. For example, they can consist of an array of numerous micron-sized needle tips connected to a base. Specifically, the "microneedles" on a microneedle patch are typically cone-shaped, with the tip forming the needle point, capable of penetrating the skin to a certain extent (e.g., piercing the stratum corneum). "Microneedle-like structures" refer to other similar morphological designs that also possess needle tips capable of piercing the skin. For example, the base of a microneedle-like structure can be circular, square, cross-shaped, or star-shaped, with the needle tip forming at its top.

[0085] This paper provides a glassy carbon microneedle patch, comprising: a main body, and a hollow region disposed within the main body; the main body includes: a meshed substrate, wherein multiple mesh holes are spaced apart on the meshed substrate, and multiple microneedles or microneedle-like structures are disposed at the edges of the mesh holes; wherein,

[0086] The glassy carbon microneedle patch is prepared by pyrolysis of a gridded precursor under centralized heat preservation, and the gridded precursor is prepared from a carbon-based polymer.

[0087] Example 1

[0088] like Figures 1-7 As shown, to reduce defects such as foaming caused by the sintering process in glassy carbon products (such as microneedle structures), this invention provides a method for preparing glassy carbon. The glassy carbon is prepared by a concentrated heat preservation method based on a gridded precursor. Accordingly, the method includes the following steps:

[0089] S10 uses carbon-based polymer raw materials to prepare a gridded precursor, wherein the gridded precursor includes a plurality of grid holes spaced apart, the grid holes forming a grid arrangement. Multiple targets to be formed are set at the edges of the grid holes.

[0090] For example, in some embodiments, the target to be formed is provided at the intersection of the mesh holes.

[0091] For example, in some embodiments, the target to be formed can also be spaced out along the edge of the mesh holes.

[0092] S20 Place the gridded precursor in the heating chamber and start the centralized heat preservation method.

[0093] S20 includes:

[0094] S21 Selects a stress-relief temperature during the first heating stage to perform heat preservation treatment on the gridded precursor in order to relieve stress in the gridded precursor; wherein, the stress-relief temperature is selected by a first selection rule;

[0095] S22 heats up to enter the second heating stage, and in the second heating stage, the gridded precursor is again kept at a pyrolysis carbonization temperature to allow the gridded precursor to undergo pyrolysis carbonization. At this time, the target to be formed and the grid holes on the gridded precursor shrink and deform during the pyrolysis carbonization process, and the impurities generated during this process can be evenly discharged outwards through the gridd arrangement. The temperature of the second heating stage is higher than the temperature of the first heating stage. The pyrolysis carbonization temperature is selected by a second selection rule.

[0096] In the subsequent third heating stage, S30 continuously raises the temperature from the pyrolysis temperature to the target heating temperature, ultimately converting the carbon polymer into glassy carbon.

[0097] In some embodiments, the first selection rule is:

[0098] The stress relief temperature is selected from the weight loss rate fluctuation temperature (equivalent to the recommended temperature); among which,

[0099] The temperature fluctuation of the weight loss rate corresponds to the thermogravimetric differential curve (e.g., the DTG curve, see...). Figure 3 The second curve (shown as a curve) corresponds to one or more temperature values ​​corresponding to at least one curve segment (or data point) with the largest curvature change; and the temperature of the weight loss rate fluctuation is often lower than the pyrolysis temperature. The thermogravimetric differential curve represents the curve showing the rate of weight change as a function of temperature.

[0100] For example, using the DTG curve as an example, an exemplary selection rule for the stress relief temperature is illustrated:

[0101] Obtain the DTG curve of the precursor, where the DTG curve is considered to consist of multiple curve segments. At this point, the curvature change value of each curve segment before the pyrolysis temperature (e.g., before approximately 350°C in this example) can be calculated (e.g., when a curve segment involves multiple data points, the average curvature change of each data point can be calculated), and then the temperature value corresponding to the curve segment with the largest curvature change is selected as the weight loss rate fluctuation temperature.

[0102] Alternatively, in other embodiments, the user may pre-set a screening threshold to select a limited number (e.g., 1, 2, etc.) of curve segments and correspondingly provide a limited number of selectable weightlessness rate fluctuation temperatures, wherein the curvature change value of the selected curve segment is within the screening threshold.

[0103] In some embodiments, if multiple weight loss rate fluctuation temperatures occur, it is preferable to use two heat preservation treatments for stress relief. For example, if multiple weight loss rate fluctuation temperatures exist, two (or more) stress relief temperatures can be selected at intervals from the multiple weight loss rate fluctuation temperatures to avoid frequent heat preservation treatments within a single temperature range.

[0104] The second selection rule for selecting the pyrolysis temperature is:

[0105] The pyrolysis temperature is selected from the weight loss fluctuation temperature (equivalent to the recommended temperature); where the weight loss fluctuation temperature corresponds to one or more temperature values ​​corresponding to the curve segment with the largest curvature change within the range of gradually decreasing slope of the thermogravimetric analysis curve (e.g., the TGA curve). The thermogravimetric analysis curve is used to represent the relationship between weight and temperature, and is also known as the thermogravimetric loss curve.

[0106] For example, taking the TGA curve (as shown in the first curve) as an example, the selection of pyrolysis temperature is illustrated below:

[0107] The TGA curve can also be considered as being composed of several curve segments. Within the range where its slope gradually decreases (for example, the range before approximately 425°C), the curve segment with the largest change in slope is selected, and the temperature corresponding to it is the weight loss fluctuation temperature. The pyrolysis temperature obtained by this selection is approximately 350°C.

[0108] For example, in some embodiments, the temperature corresponding to the data point with the largest curvature change in the thermogravimetric analysis curve (i.e., the slope difference between the current data point and the previous data point is the largest compared to the slope difference between any two adjacent data points in the curve) can be selected as the weight loss fluctuation temperature.

[0109] In this embodiment, a combination of a single stress-relieving heat preservation treatment and a single heat preservation treatment for pyrolysis and carbonization can be used to enable the precursor to undergo relatively concentrated deformation at a relatively low pyrolysis and carbonization temperature (e.g., heat preservation treatment is only performed at 350°C in Verification Example 1), thereby reducing the influence of the heating rate on the deformation of the precursor in the third heating stage.

[0110] Of course, in other embodiments, in order to achieve more uniform stress relief and avoid improper deformation under stress relief, when there is a first number of weight loss rate fluctuation temperatures, and the first number is greater than or equal to 2, step S21 includes the following steps:

[0111] A second number of weight loss rate fluctuation temperatures are selected at intervals from a first number of weight loss rate fluctuation temperatures, and a second number of stress relief temperatures are obtained accordingly (for example, a stress relief temperature is set for each weight loss rate fluctuation temperature). The second number is less than or equal to the first number, and the stress relief temperature includes at least: a first stress relief temperature and a second stress relief temperature.

[0112] During the first heating stage, a first stress relief temperature is used for heat preservation treatment, thereby performing the first stress relief on the gridded precursor.

[0113] The stress is continuously increased from the first stress relief temperature to the second stress relief temperature and then kept at that temperature to achieve a second stress relief for the gridded precursor.

[0114] Therefore, in this embodiment, for situations where stress relief is difficult, multiple heat preservation treatments can also be used to relieve stress.

[0115] Furthermore, it is understood that the stress relief temperature (or pyrolysis carbonization) of a material is not a single temperature value, and as the material type or external processing conditions change, those skilled in the art can flexibly adjust the actual stress relief temperature or pyrolysis carbonization temperature according to the actual situation based on the weight loss rate fluctuation temperature or weight loss fluctuation temperature.

[0116] For example, in some embodiments, the stress relief temperature deviates from the given weight loss rate fluctuation temperature (e.g., the deviation is ±1℃, ±5℃, ±10℃, ±15℃, etc.).

[0117] Of course, in practical applications, the weight loss rate fluctuation temperature or weight loss fluctuation temperature can also be obtained from existing thermogravimetric analysis data, as long as the purpose of stress relief and pyrolysis carbonization is achieved.

[0118] In some embodiments, S30 includes the step of:

[0119] S31 acquires conversion information for converting the heating rate, the conversion information including: conversion temperature.

[0120] C4, and / or the transition time;

[0121] S32 is heated from the pyrolysis temperature C2 to the conversion temperature C4 at the first set sub-rate VIII-1.

[0122] Alternatively, when the heating time is at the transition moment, the heating rate is changed from the first set sub-speed VIII-1 to the second set sub-speed VIII-2.

[0123] S33 heats up to the target heating temperature C5 according to the second set sub-speed VIII-2; wherein the second set sub-speed VIII-2 is greater than the first set sub-speed VIII-1.

[0124] In some embodiments, the setting range of the first set sub-velocity VIII-1 is approximately 0.1-1°C.

[0125] / min, the setting range of the second set sub-velocity VIII-2 is approximately 1-3℃ / min.

[0126] To improve the quality of glassy carbon (e.g., reducing defect area and increasing strength), this invention proposes a centralized heat preservation method based on a gridded precursor. Unlike existing full-process gradient heat preservation processes, this invention designs the following preparation stages for glassy carbon:

[0127] (1) Mesh preparation stage; (2) Based on technical results, stress relief and pyrolysis carbonization are carried out directly in the low temperature region; (3) The continuous heating method is directly adopted to reach the target heating temperature.

[0128] In this invention, the (1)-(3) stages are used in combination, which can effectively improve the uniformity of the stress relief process of the precursor during the heating stage (avoiding stress-induced cracks or adverse deformation), and at the same time alleviate the surface damage that may be caused by the main deformation processes such as material pyrolysis carbonization and continuous heating.

[0129] Furthermore, this invention, through a combination of grid design and centralized insulation, reduces the impact of heating methods (such as rate) on the deformation of the precursor during the high-temperature stage. This eliminates the reliance on high-temperature insulation treatment and reduces process costs. Experiments have verified, for example... Figure 5 As shown, microneedle patches exhibit very few defects such as foaming, deformation, or breakage on their surface.

[0130] Furthermore, to facilitate the industrial application of centralized insulation methods, the temperatures of each insulation treatment for the low-temperature insulation of the gridded precursor can be directly obtained from the relevant thermogravimetric analysis data, which helps users quickly explore the preparation conditions for low-temperature gradient insulation.

[0131] Understandably, in order to improve the accuracy and reliability of temperature selection, the head portion of the pyrolysis curve (such as TGA or DTG) is usually discarded (for example, depending on the material type or the difference in the pyrolysis analysis instrument, the curve segment with a temperature below about 50°C may be discarded), and then the effective range of the curve is analyzed.

[0132] In some embodiments, the defined curve segment can be the length of one or more data points.

[0133] The following is Example 1, which illustrates the exemplary preparation steps of the glassy carbon microneedle patch of the present invention:

[0134] A gridded precursor was prepared using photopolymerization-based 3D printing technology, using photosensitive resin as the raw material. The gridded precursor had a grid hole linewidth (i.e., the edge width of the grid hole, or the width L1 of the edge sidewall of the grid hole) of 0.6 mm, a grid hole size (equivalent to line spacing) of 1 mm, and a main body radius (i.e., the radius of the precursor's edge) of 10 mm.

[0135] The gridded precursor is heated using a heating chamber (such as a high-temperature furnace) to convert the photosensitive resin into glassy carbon. This heating process mainly consists of three stages:

[0136] First heating stage: Step 1) Heat to the first stress relief temperature C1 at the first set speed VI (1.5℃ / min) and keep at the first stress relief temperature C1 for a first time T1 (30min). At this time, the first stress relief temperature selected by the first selection rule is 150℃.

[0137] Second heating stage: Step 2) Heat to the pyrolysis temperature C2 at the second set speed VII (1℃ / min), and hold at the pyrolysis temperature C2 for a second duration T2 (120min), wherein,

[0138] The pyrolysis temperature C2 obtained using the second selection rule is 350℃; the gridded precursor can undergo relatively uniform shrinkage and deformation during this process;

[0139] Third heating stage: Step 3) After the two heat preservation treatments in the low temperature zone are completed, the third heating stage of continuous heating is entered; specifically, the temperature is directly raised to the target heating temperature C5 (1000℃) according to the third set speed VIII (0.5℃ / min), so that the gridded precursor is converted from carbon polymer to glassy carbon material.

[0140] In this verification example 1, a grid-like design was adopted for the precursor, with only two critical heat preservation processes performed in the low-temperature range. This effectively achieved stress relief and pyrolytic carbonization, eliminating the need for a high-temperature heat preservation process. Furthermore, the defect area (or defect generation rate) of the prepared grid-like microneedles could be effectively controlled to within 1%.

[0141] (Product quality is excellent). That is, the surface of the meshed microneedles has good continuity and is free from defects such as foaming, cracks, and deformation. Because it also has high strength, it is suitable for practical industrial applications.

[0142] It should be noted that this experiment used the defect area (i.e., the percentage of defect area to the total surface area of ​​the meshed microneedles) to evaluate the product quality of the meshed microneedles. Specifically, when the defect area is between 0-5%, the product quality is excellent; when the defect area is between 5-15%, the product quality is good; and when the defect area exceeds 15%, the product quality is poor.

[0143] For example, in some embodiments, since the present invention reduces the dependence of the third heating stage on the heating rate, variable-speed heating can also be performed in the third heating stage.

[0144] The recommended rate-of-motion point (equivalent to the recommended temperature) for converting the heating rate is the temperature corresponding to the data point where the slope of the thermogravimetric analysis curve is 0 or approximately 0 (within approximately ±0.001) as the slope gradually increases. Figure 3 The recommended shift point obtained is approximately 600℃. Furthermore, the actual shift point selected should ideally not be lower than the recommended shift point (or generally only within 1℃, 5℃, 10℃, etc., of the recommended shift point).

[0145] The effect of variable speed heating was verified using Example 2 and Comparative Example 1:

[0146] In this verification example 2, the same gridded precursor as in verification example 1 was selected for centralized heat preservation treatment.

[0147] Centralized insulation treatment includes:

[0148] First heating stage: Heat to the first stress relief temperature C1 (150℃) at the first set speed VI (1.5℃ / min) and hold at the first stress relief temperature for 30 min; Heat to the second stress relief temperature C3 (250℃) at the fourth set speed VIV (1℃ / min) and hold at the second stress relief temperature for 60 min.

[0149] Second heating stage: Increase the temperature from 250℃ to 350℃ at a rate of 1℃ / min and hold for 120min;

[0150] The third heating stage: The temperature is increased from 350℃ at a rate of 0.5℃ / min, and then rises to 600℃.

[0151] Then increase the temperature to 1000℃ at a rate of 2℃ / min.

[0152] The surface phase of the product prepared in Example 2 can also be found in [reference needed]. Figure 5 As shown. Therefore,

[0153] The meshed microneedles prepared by this invention still have good surface morphology even at a microscopic angle.

[0154] Comparative Example 1

[0155] The differences in preparation processes between Comparative Example 1 and Verification Example 2 are shown in Table 1:

[0156] Table 1

[0157]

[0158] In some embodiments, the method further includes the step of:

[0159] S200 When the glass carbon preparation enters the centralized heat preservation method stage (preferably the second or third heating stage), the concentration index of impurities discharged through the exhaust pipe of the heating chamber is monitored.

[0160] The impurities include: a first type of impurities, and the first type of impurities includes one or more of the following:

[0161] Carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, and nitrogen;

[0162] S201 automatically adjusts the centralized heat preservation method based on the concentration index and the current state of the centralized heat preservation method; wherein, the concentration index includes: a method for characterizing the concentration of the first type of impurities.

[0163] The first concentration indicator; accordingly, S201 includes the following steps:

[0164] S11 When the centralized heat preservation method enters the pyrolysis temperature and reaches the first set time but does not reach the second duration T2, and the first concentration index is within the first concentration threshold range X1, a first time reduction signal is sent to the gradient control module (or control unit) of the heating box, wherein the gradient control unit can reduce the second duration T2 in response to the first time reduction signal.

[0165] S12 When the centralized heat preservation method enters the pyrolysis temperature and reaches or exceeds the second duration T2, and the first concentration index belongs to the corresponding second concentration threshold range X2, a first delay signal is sent to the control unit, wherein the control unit can extend the second duration T2 in response to the first delay signal.

[0166] In a preferred embodiment, the concentration of nitrogen (or a nitrogen-containing gas) is selected as the first concentration index in this invention.

[0167] In some embodiments, the second type of impurity includes: tar.

[0168] In the centralized heat preservation method, the second type of impurities discharged through the heating chamber can also be monitored.

[0169] The second concentration index of the second type of impurities is obtained, and the second concentration index, the first concentration index and the current process status are used to monitor and adjust the parameters.

[0170] It is understandable that the temperature for thermal insulation treatment is determined not only by the direct thermogravimetric analysis results of the meshed precursor (e.g., ... Figure 3 The analysis (as shown) yields the results; it can also be the experience value collected by engineers after process debugging.

[0171] In this embodiment, nitrogen and second-type impurities, among other limited factors, are preferably used to monitor and automatically adjust the centralized insulation method. This automated adjustment process based on limited factors can also reduce the accuracy requirements for setting process parameters in the early stages.

[0172] For example, at the beginning of the preparation, only a rough temperature for heat preservation can be selected based on pyrolysis data (or the heat preservation temperature can be initially selected based on the engineer's experience). Then, the heat preservation temperature can be adjusted relatively precisely according to the actual processing conditions by an automated adjustment process, thereby helping the engineer to quickly find the preparation conditions and reducing the cost of process application to a certain extent.

[0173] In some embodiments, the steps further include:

[0174] During the heating stage of the gridded precursor, an inert gas (preferably argon) is introduced into the heating chamber to expel the impurities through the exhaust pipe. The introduction rate of the inert gas is approximately 10-60 cm⁻¹. 3 / min;

[0175] The concentration of the impurities is collected by a gas monitoring device connected to the exhaust pipe.

[0176] To minimize the impact of rapid deformation during stress relief and pyrolysis carbonization processes on the gridded precursor during centralized heat preservation, the gridded precursor is designed symmetrically. For example, in some embodiments, the gridded precursor includes a main body and a hollow region disposed in the middle of the main body, with the main body uniformly arranged around the edge of the hollow region. The uniformly arranged grid holes cooperate with the hollow region along the middle, thereby forming an impurity discharge space on the gridded precursor that facilitates the uniform discharge of impurities.

[0177] For example, in some embodiments, the edges of the body may be one or more of the following shapes:

[0178] Circle, oval, rounded rectangle.

[0179] For example, in some embodiments, the base of the target to be formed may be one or more of the following shapes: circular, square, cross-shaped, or star-shaped.

[0180] In some embodiments, the steps further include:

[0181] A carbon-rich photopolymer material is provided as a raw material, and process parameters for preparing the gridded precursor based on the photopolymer material are obtained. The process parameters include one or more of the following: grid hole size, size of the target to be formed, and thickness of the gridded precursor.

[0182] The process parameters are input into a photopolymerization-based 3D printing system, and the photopolymerization material is discretely and stacked by the 3D printing system to prepare the corresponding gridded precursor.

[0183] For example, 3D printing technology based on photopolymerization principles and photopolymerization molding technology based on microtemplate processes can be used to prepare meshed precursors. Among them, 3D printing technology based on photopolymerization is used to prepare microneedles, including one or more of the following: stereolithography (SLA), two-photon polymerization (TPP), digital light processing (DLP), liquid crystal display (LCD) polymerization, continuous liquid interface fabrication (CLIP), and static light projection printing (SOPL). This type of technology is based on digital models and manufactures three-dimensional entities in a discrete and stacked manner by controlling the light source.

[0184] For example, polymer microneedle precursors can also be prepared using photopolymerization molding technology based on microtemplate processes.

[0185] The mold is prefabricated by methods such as etching and 3D printing, and then the microneedle structure is obtained by filling it with photopolymer material, exposure curing and demolding.

[0186] The gridded microneedle product prepared by this application using 3D printing technology, precursor optimization design and centralized heat preservation method has good surface continuity (almost no obvious defects, uniform mechanical properties), improved strength and conductivity, and improved reliability and service life in actual application.

[0187] This embodiment introduces 3D printing technology for precursor preparation, which facilitates customized production of microneedle products. Furthermore, experimental verification shows that the mesh design combined with the low-temperature gradient insulation process employed in this application can effectively alleviate or reduce defects that may occur in the sintering process of the 3D-printed precursor.

[0188] Of course, in other embodiments, the precursor of the microneedle can also be manufactured using a molding method.

[0189] Furthermore, to improve the synergy between the gridded design and the low-temperature gradient insulation process, when the gridded precursor adopts a ring or rounded corner design, and the edge width L1 of the grid holes in the precursor is less than or equal to approximately 2 mm, and the radius L2 of the main body is less than or equal to approximately 100 mm, the overall shape of the gridded precursor remains good after the low-temperature gradient insulation process, with no obvious defects. The verification results are shown in Table 2.

[0190] Table 2

[0191]

[0192] Note: The other preparation processes for the gridded precursors in Table 2 are the same as in Validation Example 1;

[0193] The experimental data in Table 2 further show that the gridded process design provided by the embodiments of the present invention can achieve uniform stress relief and proportional shrinkage deformation (e.g., the shrinkage rate of each local area is approximately 25%), and the defect area of ​​the final product is significantly reduced.

[0194] Conversely, see Figure 8 As shown, using a similar fabrication process as in Verification Example 1, microneedles designed as circles with a radius of 8 mm and rectangles with a length of 8 mm (which were not designed with a grid) were processed using a low-temperature gradient process. The resulting microneedles were severely deformed and could not meet the requirements of practical applications.

[0195] Therefore, based on the gridded process design proposed in this embodiment, when it needs to be applied to different process applications, users can also make relatively flexible adjustments to the shape and size of the product in terms of morphological design and gridded distribution according to actual product requirements (such as when manufacturing medical devices, sensors and other parts of different sizes and performance) to ensure the reliability of the final molded product.

[0196] In this invention, the use of a grid design is beneficial for the precursor to form a uniform stress distribution in its structure, as well as a space for uniform impurity discharge. At the same time, the corresponding centralized heat preservation treatment, combined with the uniform stress distribution and the space for uniform impurity discharge, enables the core processes such as uniform and stable stress relief and pyrolysis carbonization to be achieved in stages.

[0197] Furthermore, the present invention utilizes a space design that allows for uniform discharge of impurities in conjunction with centralized heat preservation treatment, which enables the main stages of pyrolysis and carbonization to be concentrated (firstly, by concentrating the time and temperature ranges, and secondly, by concentrating the exhaust from the exhaust perspective), making it easier for users to achieve centralized monitoring of the pyrolysis and carbonization process during production.

[0198] Example 2

[0199] The centralized heat preservation method in this invention involves two aspects: first, centralized gradient heat preservation in the low-temperature region; and second, rapid heating in the subsequent high-temperature stage. Furthermore, to accelerate the process during the high-temperature stage, this invention also provides a preparation method incorporating a variable-speed adjustment process, and this preparation method may include steps identical or similar to those in Example 1.

[0200] In some embodiments, the preparation method further includes the steps of:

[0201] Monitor and collect the concentration indicators of impurities;

[0202] When the concentration index is lower than the set first threshold range A, a first speed change signal is sent to the heating chamber (with a gradient control unit);

[0203] The heating chamber responds to the first speed change signal by changing the current first set sub-speed (i.e., the first heating speed) to the second set sub-speed (i.e., the second heating speed).

[0204] For example, in some embodiments, the first set sub-velocity is approximately 0.5°C / min, and the second set sub-velocity is approximately 2°C / min.

[0205] In this embodiment, the variable-speed heating process can be controlled in real time using concentration indicators.

[0206] It is worth noting that, unlike the existing glass carbon preparation process, this invention focuses on the preparation of glass carbon for microneedle-shaped products. For microneedle products with small dimensions, the shrinkage rate is too fast during the actual sintering process, which can lead to undesirable deformation, thereby affecting the surface morphology and strength of the final microneedle and making it difficult to apply in practice.

[0207] However, this invention, by proposing a precursor grid design and centralized heat preservation treatment, reduces the impact of the heating rate on the third heating stage to a certain extent. Correspondingly, this also reduces the fluctuation of the impurity content discharged during the third heating stage to a certain extent. Therefore, in this embodiment, by combining monitoring of key impurity parameters during the third heating stage with centralized heat preservation, the reliability and stability of the monitoring results can be guaranteed, thereby effectively optimizing product quality.

[0208] Example 3

[0209] To improve the reliability of centralized heat preservation methods (i.e., low-temperature gradient heat preservation processes) and reduce labor costs in the preparation process to some extent, this invention also provides an automated monitoring system for glassy carbon preparation, such as... Figure 9 As shown, it includes:

[0210] Gradient control module 10 (or control unit) for controlling the heating process of the heating chamber;

[0211] The low-temperature gradient process monitoring subsystem (also known as the centralized insulation monitoring subsystem) includes:

[0212] An impurity monitoring module 20 is connected to the exhaust pipe of the heating chamber and is configured to monitor the concentration of impurities discharged through the exhaust pipe; wherein the impurities include: a first type of impurities, and the first type of impurities includes one or more of the following: carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide and nitrogen.

[0213] The signal conditioning module 21 is configured to automatically adjust the centralized heat preservation method based on the concentration index and the current state of the centralized heat preservation method; wherein, the concentration index includes a first concentration index characterizing the concentration of a first type of impurity; correspondingly, the signal conditioning module 21 includes:

[0214] The first adjustment unit 11 is configured to send a first time reduction signal to the gradient control module of the heating box when the centralized heat preservation method enters the pyrolysis temperature and reaches the first set time but does not reach the second time T2 (i.e. the preset pyrolysis heat preservation time), and the first concentration index is within the first concentration threshold range X1. The control unit is able to reduce the second time T2 in response to the first time reduction signal.

[0215] And / or, the second adjustment unit 12 is configured to send a first delay signal to the control unit when the centralized heat preservation method enters the pyrolysis temperature and reaches or exceeds the second duration T2, and the first concentration index belongs to the corresponding second concentration threshold range X2, wherein the control unit is able to extend the second duration T2 in response to the first delay signal.

[0216] When the first concentration index enters the first concentration threshold range X1, the heat preservation ends and the rapid heating phase begins.

[0217] In some embodiments, the signal conditioning module 21 further includes:

[0218] The speed control unit 13 is configured to send a first speed adjustment signal to the control unit when the centralized heat preservation method raises the temperature from the pyrolysis temperature to the target heating temperature and monitors that the first concentration index belongs to the third concentration threshold range X3. The control unit is able to increase the speed of the third set speed VIII (i.e., the heating speed of the third heating stage) in response to the first speed adjustment signal.

[0219] In some embodiments, the impurity monitoring module 20 is further configured to monitor a second type of impurity discharged through the heating chamber during the centralized heat preservation method phase.

[0220] In some embodiments, the signal conditioning module 21 further includes:

[0221] The integrated adjustment unit 14 is configured to send a first time reduction signal to the control unit of the heating chamber when the heating chamber has entered the pyrolysis temperature and reached the first set time but has not reached the second time T2, and the first concentration index is within the first concentration threshold range X1 and the second concentration index is within the fourth concentration threshold range X4. The control unit is able to reduce the second time T2 in response to the first time reduction signal.

[0222] Specifically, first, second, and fifth concentration threshold ranges are set sequentially based on the concentration of the first type of impurities. Fourth and sixth concentration threshold ranges are set sequentially based on the concentration of the second type of impurities.

[0223] In some embodiments, the signal conditioning module 21 further includes a user conditioning unit 15, configured to send a first prompt signal to the user when the heating chamber enters the pyrolysis temperature and when the first concentration index belongs to the fifth concentration threshold range X5, or when the second concentration index belongs to the sixth concentration threshold range X6, so as to prompt the user to adjust the centralized heat preservation method of the gradient control module.

[0224] In this embodiment, the pyrolysis holding time can be dynamically adjusted based on the ranges corresponding to the first and second concentration indicators. For example, when the concentration indicators are relatively low (i.e., the first concentration indicator is within the first concentration threshold range and the second concentration indicator is within the fifth concentration threshold range), the holding time at the pyrolysis temperature is automatically reduced.

[0225] When at least one concentration indicator is too high, for example, when the first concentration indicator falls within the fifth concentration threshold range X5, or when the second concentration indicator falls within the sixth concentration threshold range X6, then manual intervention is urgently introduced.

[0226] Alternatively, in some embodiments, the integrated adjustment unit 14 is also configured to send a first delay signal to the control unit when the first concentration index is within the second concentration threshold range, or when the second concentration index is within the seventh concentration threshold range (i.e., between the fourth and sixth concentration threshold ranges), and correspondingly, the control unit can extend the second duration T2 in response to the first delay signal.

[0227] In actual processing, due to different processing environments, equipment models, and product requirements,

[0228] This invention addresses the potential for frequent adjustments to preparation conditions by employing an automated adjustment process that targets only critical nodes (such as the pyrolysis holding time in the low-temperature region). This allows for flexible and dynamic control of preparation conditions and enables multi-level adjustments using a limited set of factors, thus reducing application costs.

[0229] The pyrolysis holding time can be more precisely and automatically adjusted, reducing the need for manual intervention by users.

[0230] In some embodiments, the system further includes: a gridded process monitoring subsystem, the gridded process monitoring subsystem comprising:

[0231] The first view acquisition module 30 is configured to acquire morphological information of the gridded precursor, the morphological information including: a first image for displaying the size characteristics of the gridded precursor;

[0232] The view analysis module 40 is configured to obtain the feature indicators of the meshed precursor based on the morphological information; wherein the meshed precursor includes: a main body, and a hollow area disposed in the middle of the main body; the feature indicators include a first feature indicator for standardizing the size features, and the first feature indicator includes: the line width of the mesh holes;

[0233] The execution condition judgment module 50 is configured to determine whether the gridded precursor meets the preset execution conditions of the centralized heat preservation method (such as the standard line width of the grid holes) based on the characteristic indicators.

[0234] In some embodiments, the morphological information further includes: a second image for displaying the morphological features of the gridded precursor; correspondingly, the feature index further includes: a second feature index obtained from the second image for representing the number of defects.

[0235] For example, in some embodiments, an image size measuring instrument may be used to obtain the corresponding size data.

[0236] In some embodiments, the execution condition determination module 50 includes:

[0237] The first judgment unit 51 is configured to determine the monitoring level of the centralized heat preservation method based on the first characteristic indicator, and is divided into: Level 1 monitoring and Level 2 monitoring based on the difference between the first characteristic indicator and the standard size characteristic.

[0238] The second judgment unit 52 is configured to determine the monitoring level of the centralized heat preservation method based on the second characteristic index, and is divided into: Level 1 monitoring and Level 2 monitoring based on the difference between the second characteristic index and the standard morphological characteristics.

[0239] The execution risk analysis unit 53 is configured to determine the execution risk level of the centralized insulation method based on the monitoring level and the surveillance level; wherein, when both the monitoring level and the surveillance level are level one, the execution risk level is low, and a first start signal is sent to the gradient control module, and the gradient control module starts the centralized insulation method in response to the first start signal and starts the signal adjustment module 21.

[0240] When the monitoring level is level 1 and the surveillance level is level 2, or when the monitoring level is level 2 and the surveillance level is level 1, and the execution risk level is medium, a second start signal is sent to the gradient control module. The gradient control module starts in response to the second start signal and executes the centralized heat preservation method in response to the gradient control parameters input by the user.

[0241] When both the monitoring level and the surveillance level are level two, the execution risk level is high.

[0242] It then sends a prompt signal to the user and receives control signals input by the user in real time within a set time.

[0243] In some embodiments, when the difference between the first feature index (such as the line width of the mesh hole) and the standard size feature (such as the preset standard line width) is less than or equal to the preset first difference, the first-level monitoring (mode) is selected; when the difference is greater than the first difference but less than the preset second difference, the second-level monitoring (mode) is selected.

[0244] In some embodiments, when the difference between the second characteristic indicator (such as the number of defects) and the standard morphological characteristic (the number of standard defects) is less than or equal to a preset third difference, the first-level monitoring (mode) is selected; when the corresponding difference is greater than the third difference and less than the preset fourth difference, the second-level monitoring (mode) is selected.

[0245] For example, in some embodiments, when facing mass production processes, before using a batch of gridded precursors for centralized heat preservation, a portion of the gridded precursors can be selected as test samples, and their monitoring level (or surveillance level) under the low-temperature gradient heat preservation process can be determined by the gridded process monitoring subsystem, thereby improving the effectiveness of the entire preparation process.

[0246] Furthermore, this embodiment utilizes two explicit indicators—linewidth and defect quantity—to quickly and standardizedly assess the quality of the test samples, thereby enabling flexible linkage with subsequent low-temperature gradient processes. For example, when the monitoring and control levels of the test samples are both at level one, it is preferable to activate the signal conditioning module 21 to dynamically adjust the low-temperature process.

[0247] In some embodiments, the number of defects can also be characterized by the defect area.

[0248] It should be noted that in this embodiment, "monitoring" and "surveillance" have the same meaning, and the different expressions are used here only for the purpose of distinguishing them.

[0249] In this embodiment, to improve the accuracy and reliability of automated monitoring, a monitoring scheme based on multi-level dynamic adjustment of different types of parameters is proposed. Furthermore, to reduce the difficulty of monitoring the process, this invention mainly focuses on monitoring key dimensional features in the gridding technology (such as the width of the grid holes) and key output impurities in the centralized insulation method (such as nitrogen), thereby utilizing a finite combination of factors to form a multi-level monitoring mode. Thus, this multi-level dynamic adjustment monitoring scheme can reduce the possibility of process failure due to monitoring errors (or malfunctions of individual monitoring devices) by utilizing a combination of finite factors; at the same time, it can also avoid the monitoring and analysis difficulties that multi-factor monitoring may bring to a certain extent (conversely, this invention uses finite, standardized factor comparison to quickly identify difficult problems (such as when the risk level is high), and then notify the user immediately, achieving synergy between automated control and manual monitoring).

[0250] In some embodiments, the system further includes: an evaluation subsystem comprising:

[0251] The second view acquisition module 60 is configured to acquire a third image of the meshed microneedle product prepared from the meshed precursor.

[0252] Image comparison module 70 is configured to compare the third image and the first image to obtain shrinkage data and morphological difference data of the meshed microneedle product, wherein the morphological difference data refers to the deformation of the meshed precursor and the meshed microneedle product at at least two points.

[0253] The difference in proportions;

[0254] The quality assessment module 80 is configured to perform product quality analysis on the meshed microneedle product based on the shrinkage data and the morphological difference data.

[0255] For example, in some embodiments, when both shrinkage data and morphological difference data fall within a preset standard range, the product quality is considered to meet expectations, and the current manufacturing process is also considered to meet specifications.

[0256] In this embodiment, image comparison technology can also be used to quickly evaluate the final prepared product.

[0257] If the monitored product quality is significantly lower than expected, the user can be notified in a timely manner to adjust the process.

[0258] Example 4

[0259] The present invention also provides a semi-automated monitoring method for glassy carbon preparation, comprising the following steps:

[0260] S200 When the glass carbon preparation enters the centralized heat preservation method step, the concentration index of impurities discharged through the exhaust pipe of the heating box is monitored; wherein, the impurities include: a first type of impurities, and the first type of impurities includes one or more of the following: carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide and nitrogen.

[0261] S201 automatically adjusts the centralized heat preservation method based on the concentration index and the current state of the centralized heat preservation method; wherein, the concentration index includes: a first concentration index for characterizing the concentration of the first type of impurities; correspondingly, S201 includes the step:

[0262] S11 When the low-temperature gradient heat preservation process reaches the pyrolysis temperature and the first set time but has not reached the second duration T2 (i.e., pyrolysis heat preservation duration), and the first concentration index falls within the first concentration threshold range X1, a first time reduction signal is sent to the gradient control module of the heating chamber, wherein...

[0263] The control unit is able to reduce the second duration T2 in response to the first time reduction signal;

[0264] S12 After the heating chamber enters the pyrolysis temperature and reaches or exceeds the second time duration T2.

[0265] When the first concentration index falls within the corresponding second concentration threshold range X2, a first delay signal is sent to the control unit, wherein the control unit is able to extend the second duration T2 in response to the first delay signal.

[0266] In some embodiments, S201 further includes the step of:

[0267] S13 When the heating chamber heats up from the pyrolysis temperature to the heating temperature, and the first concentration index is monitored to be within the third concentration threshold range X3, a first speed adjustment signal is sent to the control unit, wherein the control unit is able to increase the third set speed VIII (i.e. the heating speed of the third heating stage) in response to the first speed adjustment signal.

[0268] In some embodiments, S200 further includes the step of:

[0269] In the centralized heat preservation method steps (such as the second heating stage and the third heating stage), the second type of impurities discharged through the heating chamber are monitored.

[0270] In some embodiments, S201 includes the step of:

[0271] When the heating chamber reaches the pyrolysis temperature and a first set time has elapsed but a second time T2 has not been elapsed, and the first concentration index falls within a first concentration threshold range X1, and the second concentration index falls within a fourth concentration threshold range X4, a first time-decrease signal is sent to the control unit of the heating chamber.

[0272] The control unit is capable of reducing the second duration T2 in response to the first time reduction signal;

[0273] And / or, when the heating chamber enters the pyrolysis temperature, and when the first concentration index belongs to the fifth concentration threshold range X5 and the second concentration index belongs to the sixth concentration threshold range X6, a first prompt signal is sent to the user to prompt the user to adjust the centralized heat preservation method of the gradient control module.

[0274] In some embodiments, prior to S200, the following steps are also included:

[0275] S203 acquires morphological information of the gridded precursor, the morphological information including: a first image for displaying the size characteristics of the gridded precursor;

[0276] S204 Obtains the feature indicators of the gridded precursor based on the morphological information; wherein, the gridded precursor includes: a main body, and a hollow region disposed in the middle of the main body; the feature indicators include a first feature indicator for standardizing the size features, and the first feature indicator includes:

[0277] The edge width of the mesh holes on the main body, and the radius of the main body;

[0278] S205 determines whether the gridded precursor meets the preset execution conditions of the low-temperature gradient insulation process based on the characteristic indicators.

[0279] In some embodiments, the morphological information further includes: a second image for displaying the morphological features of the meshed precursor; correspondingly, the feature index further includes: a second feature index for representing the number of defects. The number of defects can be characterized by defect area. Defects may include:

[0280] Foaming, breaking, deformation, etc.

[0281] The defect area can be calculated through image comparison. For example, points with pixel differences between the inspection sample photo (i.e., a surface photo of the prepared glassy carbon product) and the standard sample photo (a surface photo of the glassy carbon product selected as the standard sample) can be used as defect areas to calculate the defect area. Alternatively, other automated defect detection equipment or technologies can be used to calculate the defect area (or the number of defects).

[0282] In some embodiments, S205 includes the step of:

[0283] S51 determines the monitoring level of the low-temperature gradient insulation process based on the first characteristic index, and classifies it into: Level 1 monitoring; Level 2 monitoring based on the difference between the first characteristic index and the standard size characteristic.

[0284] S52 determines the monitoring level of the low-temperature gradient insulation process based on the second characteristic index, and classifies it into: Level 1 monitoring; Level 2 monitoring based on the difference between the second characteristic index and the standard morphological characteristics.

[0285] S53 determines the execution risk level of the low-temperature gradient insulation process based on the monitoring level and surveillance level;

[0286] When both the monitoring level and the surveillance level are at level one, a first start signal is sent to the gradient control module. The gradient control module responds to the first start signal by starting the low-temperature gradient insulation process and executes S200.

[0287] When the monitoring level is level 1 and the monitoring level is level 2, or when the monitoring level is level 2 and the monitoring level is level 1, a second start signal is sent to the gradient control module. The gradient control module starts in response to the second start signal and executes the low-temperature gradient heat preservation process in response to the gradient control parameters input by the user (such as pyrolysis heat preservation time and the heating rate of the third stage heating).

[0288] When both the monitoring level and the surveillance level are level two, a prompt signal is sent to the user.

[0289] It also receives control signals input by the user in real time within a set time period.

[0290] In some embodiments, the steps further include:

[0291] S206 Acquires a third image of the meshed microneedle product prepared from the meshed precursor;

[0292] S207 compares the third image with the first image to obtain the shrinkage data and morphological difference data of the gridded microneedle product, wherein the morphological difference data is the difference between the deformation ratio of the gridded precursor and the gridded microneedle product at at least two points.

[0293] S208 performs product quality analysis on the meshed microneedle product based on the shrinkage data and the morphological difference data.

[0294] It should be noted that the threshold or range used in this invention can be adjusted by the user in conjunction with the actual process.

[0295] It should be noted that the temperature value actually selected in this invention can be the recommended temperature or a value close to the recommended temperature.

[0296] The microneedle products prepared using the gridded precursor and the controlled temperature in this invention possess multiple advantages, including high rigidity, good biocompatibility, heat resistance, chemical resistance, good conductivity, and high purity. They can be applied not only to conventional solid and hollow microneedle arrays but also to the fabrication of components for precision devices such as electrospinning nozzles, extrusion printing nozzles, brain-computer interfaces, and biochemical sensors.

[0297] Example 5

[0298] This invention also provides a method for preparing roller microneedles, comprising:

[0299] S401 Obtains a precursor prepared from a carbon-based polymer, such as Figure 9 , 10 As shown, the precursor includes: a plurality of first supports and a plurality of second supports arranged at intervals, the first and second supports intersecting to form a plurality of grid holes at intervals, and at least one support being provided with a plurality of microneedles or microneedle-like structures.

[0300] S402 performs centralized heat preservation treatment on the precursor; wherein, S402 includes the following steps:

[0301] During the first heating stage, the precursor is subjected to heat preservation treatment at a stress relief temperature to relieve stress in the precursor; wherein, the stress relief temperature is selected by a first selection rule;

[0302] The temperature is increased to enter the second heating stage, and the precursor is kept at a pyrolysis carbonization temperature again during the second heating stage so that the precursor undergoes pyrolysis carbonization. At this time, the precursor shrinks and deforms during the pyrolysis carbonization process. The pyrolysis carbonization temperature is selected by a second selection rule.

[0303] The first selection rule is: to select the stress relief temperature from the weight loss rate fluctuation temperature;

[0304] The weight loss rate fluctuation temperature corresponds to one or more temperature values ​​corresponding to at least one curve segment with the largest curvature change in the thermogravimetric differential curve, and the thermogravimetric differential curve is a curve representing the rate of weight change with temperature; the second selection rule is: select the pyrolysis temperature from the weight loss fluctuation temperature; wherein, the weight loss fluctuation temperature corresponds to one or more temperature values ​​corresponding to one curve segment with the largest curvature change in the thermogravimetric analysis curve within the range where the slope gradually decreases, and the thermogravimetric analysis curve is a curve representing the weight change with temperature.

[0305] In some embodiments, the width (i.e., line width) of the precursor's support is less than or equal to 3 mm.

[0306] In some embodiments, the precursor can be prepared using photopolymerization 3D printing technology, correspondingly...

[0307] Prior to S402, the process further includes the step of immersing the precursor in a cleaning liquid (such as an alcoholic liquid) for a first time, wherein the alcoholic liquid refers to an alcohol solution or an alcohol solvent.

[0308] In some embodiments, the alcohol solution can be ethanol, propanol, methanol, etc., of various concentrations.

[0309] The alcohol solution is preferably high-concentration ethanol, such as anhydrous ethanol.

[0310] In some embodiments, the initial time can be set by the user. For example, the initial time can be approximately 5 minutes, during which agitation and ultrasonic cleaning can be used to accelerate the cleaning process until the residual liquid on the surface of the precursor (which is the liquid raw material that failed to form on the surface of the precursor during the photopolymerization printing process) is washed away.

[0311] In some embodiments, after soaking and drying, a secondary photocuring process is required to fully cross-link and cure the material (this step can also be performed by high-pressure air washing or high-speed centrifugation to remove residual resin material in the support).

[0312] In some embodiments, precursors can also be prepared by methods such as fused deposition modeling or die forming.

[0313] In some embodiments, the precursor is designed in a columnar shape, wherein a plurality of first supports are arranged in at least one ring around the column, and a plurality of second supports are arranged at intervals along the length direction of the first supports and intersect with the plurality of first supports to form a columnar frame; the precursor further includes: a third support and a fourth support disposed inside the columnar frame, wherein the third support and the fourth support are arranged intersectingly in at least two directions, and the two ends of the third support and the fourth support are respectively connected to the first support or the second support to support the columnar frame; wherein the sides of the first support and / or the second support are provided with a plurality of microneedles or microneedle-like structures.

[0314] In some embodiments, the length of the first support of the precursor is less than or equal to 200 mm, and the width of the columnar frame (e.g., when the columnar frame is a cylindrical structure, the width can refer to the radius) is less than or equal to 100 mm.

[0315] It is worth noting that even tiny defects can severely impact the quality of microneedle products. Furthermore, as the size of the precursor gradually increases, the processing difficulty also increases (making it easier for defects to arise due to deformation). The centralized heat preservation method proposed in this invention can increase the size of the product while ensuring the quality of the microneedles (i.e., controlling the number of defects).

[0316] Verification has shown that even when the width of the current drive body reaches 100mm and the length reaches 200mm, the needle roller product obtained by the final heat treatment can still maintain good shape and performance during rapid heating.

[0317] Table 3

[0318] 2-1 20mm 80mm 1mm excellent 2-2 90mm 80mm 1mm excellent 2-3 20mm 190mm 1mm excellent 2-4 20mm 80mm 3mm excellent 2-5 100mm 200mm 3mm excellent

[0319] The heating process parameters used in Table 3 are shown in Table 3. Figure 2b .

[0320] In some embodiments, S402 further includes the step of: continuously increasing the temperature from the pyrolysis temperature to the target heating temperature in a subsequent third heating stage.

[0321] In some embodiments, during the third heating stage, the temperature is increased to a variable-speed temperature point using a first heating rate, and then increased to a target heating temperature using a second heating rate. The second heating rate is greater than the first heating rate, and the variable-speed temperature point is the temperature point corresponding to the point where the slope of the thermogravimetric analysis curve is less than a preset slope threshold as the slope gradually increases.

[0322] In some embodiments, the method further includes: during the second heating stage, introducing gas into the heating chamber containing the precursor.

[0323] In some embodiments, the gas introduction rate is 10-60 cm⁻¹. 3 / min.

[0324] In some embodiments, the method further includes:

[0325] During the second heating stage, the concentration of impurities in the precursor during the pyrolysis and carbonization process is collected using the gas; wherein, the impurities include: a first type of impurities, and the first type of impurities includes one or more of the following: carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, and nitrogen.

[0326] When the pyrolysis temperature reaches the first set time but does not reach the second duration T2, and the first concentration index is within the first concentration threshold range X1, a first time reduction signal is sent to the heating chamber.

[0327] Alternatively, when the centralized heat preservation method enters the pyrolysis temperature and reaches or exceeds the second duration T2, and the first concentration index belongs to the corresponding second concentration threshold range X2, a first delay signal is sent to the heating box; wherein, the second duration is a preset pyrolysis heat preservation treatment duration.

[0328] Example 6

[0329] The present invention also provides a roller microneedle preparation system corresponding to the above embodiment five, comprising:

[0330] The centralized insulation module is configured to handle centralized insulation treatment of the precursor; wherein,

[0331] The precursor is obtained by preparing a carbon-based polymer and includes: a plurality of first supports and a plurality of second supports arranged at intervals, the first and second supports intersecting to form a plurality of spaced mesh holes, and at least one support having a plurality of microneedles or microneedle-like structures; and the centralized heat preservation module includes:

[0332] The first heating unit is configured to perform a heat preservation treatment on the precursor at a stress relief temperature during a first heating stage, so as to relieve stress in the precursor; wherein the stress relief temperature is selected by a first selection rule.

[0333] The second heating unit is configured to raise the temperature to enter the second heating stage, and to use the pyrolysis carbonization temperature to perform heat preservation treatment on the precursor again during the second heating stage, so that the precursor undergoes pyrolysis carbonization. At this time, the precursor shrinks and deforms during the pyrolysis carbonization process; the pyrolysis carbonization temperature is selected by a second selection rule.

[0334] The first selection rule is: to select the stress relief temperature from the weight loss rate fluctuation temperature;

[0335] The weight loss rate fluctuation temperature corresponds to one or more temperature values ​​corresponding to at least one curve segment with the largest curvature change in the thermogravimetric differential curve, and the thermogravimetric differential curve is a curve representing the rate of weight change with temperature; the second selection rule is: select the pyrolysis temperature from the weight loss fluctuation temperature; wherein, the weight loss fluctuation temperature corresponds to one or more temperature values ​​corresponding to one curve segment with the largest curvature change in the thermogravimetric analysis curve within the range where the slope gradually decreases, and the thermogravimetric analysis curve is a curve representing the weight change with temperature.

[0336] It is understood that the centralized heat preservation method for preparing needle rollers in this invention can also adopt the same or similar steps as any of the above embodiments. Therefore, the methods and systems in Embodiments 5 and 6 can also include the steps or unit modules in any of the above embodiments.

[0337] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0338] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a computer terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0339] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for preparing roller microneedles, characterized in that, include: S401 Obtain a precursor prepared from a carbon-based polymer, the precursor comprising: a plurality of first supports and a plurality of second supports arranged at intervals, the first and second supports intersecting to form a plurality of mesh pores at intervals, and at least one support having a plurality of microneedles or microneedle-like structures disposed thereon; S402 performs centralized heat preservation treatment on the precursor; wherein, S402 includes the following steps: During the first heating stage, the precursor is subjected to heat preservation treatment at a stress relief temperature to relieve stress in the precursor; wherein, the stress relief temperature is selected by a first selection rule; The temperature is increased to enter the second heating stage, and the precursor is kept at a pyrolysis carbonization temperature again during the second heating stage so that the precursor undergoes pyrolysis carbonization. At this time, the precursor shrinks and deforms during the pyrolysis carbonization process. The pyrolysis carbonization temperature is selected by a second selection rule. The first selection rule is: selecting the stress relief temperature from the weight loss rate fluctuation temperature; wherein the weight loss rate fluctuation temperature corresponds to one or more temperature values ​​corresponding to at least one curve segment with the largest curvature change in the thermogravimetric differential curve, and the thermogravimetric differential curve is a curve representing the rate of weight change with temperature; the second selection rule is: selecting the pyrolysis temperature from the weight loss fluctuation temperature; wherein the weight loss fluctuation temperature corresponds to one or more temperature values ​​corresponding to one curve segment with the largest curvature change in the range where the slope of the thermogravimetric analysis curve gradually decreases, and the thermogravimetric analysis curve is a curve representing the weight change with temperature.

2. The method according to claim 1, characterized in that, The line width of the bracket is less than or equal to 3mm.

3. The method according to claim 1 or 2, characterized in that, Prior to S402, the step of immersing the precursor in a cleaning liquid for a first time is also included.

4. The method according to claim 2, characterized in that, The precursor is designed in a columnar shape, wherein a plurality of first supports are arranged in at least one ring around the column, and a plurality of second supports are arranged at intervals along the length direction of the first supports and intersect with the first supports to form a columnar frame; the precursor further includes: a third support and a fourth support disposed inside the columnar frame, wherein the third support and the fourth support are arranged intersecting in at least two directions, and the two ends of the third support and the fourth support are respectively connected to the first support or the second support to support the columnar frame; The first and / or second supports have multiple microneedles or microneedle-like structures on their sides.

5. The method according to claim 4, characterized in that, The length of the first support is less than or equal to 200 mm, and the width of the columnar frame is less than or equal to 100 mm.

6. The method according to claim 1, characterized in that, S402 also includes the following steps: In the subsequent third heating stage, the temperature is continuously increased from the pyrolysis temperature to the target heating temperature.

7. The method according to claim 6, characterized in that, In the third heating stage, the temperature is increased to the variable-speed temperature point using a first heating rate, and then increased to the target heating temperature using a second heating rate. The second heating rate is greater than the first heating rate, and the variable-speed temperature point is the temperature corresponding to the data point with a slope of 0 or within ±0.001 as the slope of the thermogravimetric analysis curve gradually increases.

8. The method according to claim 1, characterized in that, The method further includes: during the second heating stage, introducing gas into the heating chamber where the precursor is located; And / or, the carbon-based polymer includes: a carbon-rich polymer, or a product obtained by further modification or alteration of the carbon-rich polymer; the carbon-rich polymer includes one or more of the following: polyurethane, epoxy resin, phenolic resin, polyacrylonitrile, polyimide, polystyrene, polytetrafluoroethylene, polyethylene, polyaniline; And / or, the method for preparing the precursor includes: molding, and / or 3D printing.

9. The method according to claim 8, characterized in that, The method further includes: During the second heating stage, the concentration index of impurities in the precursor during the pyrolysis and carbonization process is collected through the gas; the concentration index includes: a first concentration index for characterizing the concentration of a first type of impurity; wherein, the impurities include: a first type of impurity, and the first type of impurity includes one or more of the following: carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, and nitrogen. When the pyrolysis temperature reaches the first set time but has not reached the second duration T2, and the first concentration index is within the first concentration threshold range X1, a first time reduction signal is sent to the heating chamber; or, when the centralized heat preservation treatment enters the pyrolysis temperature and reaches or exceeds the second duration T2, and the first concentration index is within the corresponding second concentration threshold range X2, a first delay signal is sent to the heating chamber; wherein, the second duration is the preset pyrolysis heat preservation treatment duration.

10. A system for preparing roller microneedles, characterized in that, include: A centralized insulation module is configured to perform centralized insulation treatment on a precursor; wherein the precursor is obtained from a carbon-based polymer, and the precursor includes: a plurality of first supports and a plurality of second supports arranged at intervals, the first and second supports intersecting to form a plurality of spaced mesh holes, and at least one support having a plurality of microneedles or microneedle-like structures; and the centralized insulation module includes: The first heating unit is configured to perform a heat preservation treatment on the precursor at a stress relief temperature during a first heating stage, so as to relieve stress in the precursor; wherein the stress relief temperature is selected by a first selection rule. The second heating unit is configured to raise the temperature to enter the second heating stage, and to use the pyrolysis carbonization temperature to perform heat preservation treatment on the precursor again during the second heating stage, so that the precursor undergoes pyrolysis carbonization. At this time, the precursor shrinks and deforms during the pyrolysis carbonization process; the pyrolysis carbonization temperature is selected by a second selection rule. The first selection rule is: selecting the stress relief temperature from the weight loss rate fluctuation temperature; wherein the weight loss rate fluctuation temperature corresponds to one or more temperature values ​​corresponding to at least one curve segment with the largest curvature change in the thermogravimetric differential curve, and the thermogravimetric differential curve is a curve representing the rate of weight change with temperature; the second selection rule is: selecting the pyrolysis temperature from the weight loss fluctuation temperature; wherein the weight loss fluctuation temperature corresponds to one or more temperature values ​​corresponding to one curve segment with the largest curvature change in the range where the slope of the thermogravimetric analysis curve gradually decreases, and the thermogravimetric analysis curve is a curve representing the weight change with temperature.

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