Stoma base plate adhesive and preparation method thereof

Abstract

The invention relates to the technical field of medical adhesives, in particular to a stoma base plate adhesive and a preparation method thereof. In the prior art, the problems of insufficient adhesion stability, non-repeated adhesion and the like in a wet environment exist. By means of the three-area gradient functional structure design, the three-area gradient functional structure design comprises the inner ring area close to the stoma, the middle ring area in middle transition and the outer ring area on the periphery, the inner ring area can resist high-concentration exudate invasion and keep adhesive force, and the middle ring area absorbs a small amount of exudate and meanwhile achieves the repeatable pasting function through the thermal response characteristic; the outer ring area is mainly attached to the relatively dry skin surface, and stable peripheral anchoring is provided; meanwhile, a micropore array structure is constructed on the skin contact surface of the mucilage glue, so that the overall adhesive force is remarkably enhanced; the adhesive provided by the invention keeps stable adhesion for a long time in a high-humidity exudation environment, is not easy to cause adhesion failure or spontaneous falling, and can be torn and re-adhered for many times to keep good viscosity.

Description

Technical Field

[0001] This invention relates to the field of medical adhesives, and more particularly to an adhesive for stoma base plates and its preparation method. Background Technology

[0002] Stoma patients need to have an ostomy bag secured to the abdominal skin, usually by medical adhesive on the stoma baseplate to collect excrement. Traditional stoma baseplates often use hydrocolloid adhesives, which contain hydrophilic microparticles dispersed in a viscoelastic matrix. After absorbing a certain amount of exudate, they form a gel, thus both adhering to the skin and sealing leakage.

[0003] However, when a large amount of fluid drains from the stoma, the baseplate adhesive rapidly absorbs the fluid, swells, softens, and loses its stickiness, leading to adhesive failure and spontaneous detachment of the device. This problem of insufficient adhesive stability in a wet environment occurs frequently in clinical practice; when there is excessive exudate, the duration of skin barrier adhesion can be drastically shortened from the normal approximately 4 days to only 0.5 days, mainly due to adhesive detachment caused by exudate. Premature adhesive failure not only increases the burden on patients by requiring frequent baseplate replacements but can also lead to leakage irritating the skin and causing skin inflammation. In addition, most existing stoma baseplate adhesives are designed for single use and lack re-adhesion properties. Once the user removes the baseplate, it is often impossible to reattach it after replacement or adjustment because traditional adhesives leave residues and significantly reduced stickiness after removal, making it difficult to re-adhere firmly. Even if repeated re-application is attempted, the adhesive strength is usually significantly reduced, failing to guarantee a seal and fixation. This causes inconvenience in situations requiring repeated stoma checks or repositioning within a short period.

[0004] In recent years, to reduce skin damage, some wound dressings and medical tapes have begun to use soft silicone gel adhesives, which cause less skin damage during peeling and can be reapplied to a certain extent. However, silicone adhesives themselves do not have the ability to absorb liquids, and pure silicone bases are difficult to manage the absorption of stoma exudate, and direct use in stomas may pose a risk of leakage. In addition, researchers have developed biomimetic adhesives inspired by marine mussels. The catechin groups in mussel byssal proteins can form hydrogen bonds, coordination bonds, and other interactions with the substrate under wet conditions, thereby generating strong underwater adhesion. However, simply adding "mussel glue" components can also bring new problems, such as the high activity of catechins potentially affecting the stability of the colloid or causing excessive cross-linking and brittleness of the gel.

[0005] In summary, existing technologies still have significant room for improvement in stoma baseplate adhesives, and there is an urgent need for a new stoma baseplate adhesive that comprehensively utilizes multi-component composites and structural innovations to achieve regional division of labor and collaboration. Summary of the Invention

[0006] This invention provides an adhesive for stoma baseplates and its preparation method, overcoming the shortcomings of existing stoma baseplate adhesives that are prone to loss of adhesion and detachment in humid environments and cannot be reused. The adhesive of this invention, through a special material combination and structural design, achieves long-term stable adhesion to skin with exudate and can be repeatedly peeled off and re-applied while maintaining its adhesiveness, thereby improving the safety and convenience of stoma care.

[0007] The specific technical solution is as follows: An adhesive for stoma baseplate and its preparation method are as follows: S1: Material preparation for the outer ring region.

[0008] S11: Polycaprolactone diol is reacted with excess diisocyanate, then hydroxyethyl methacrylate is added, and dibutyltin dilaurate catalyst is added dropwise to prepare a polyurethane acrylate prepolymer at 70°C; the polyurethane acrylate prepolymer is dissolved in N,N-dimethylformamide solvent, and dopamine hydrochloride is added under nitrogen protection and stirred to prepare polydopamine-grafted polyurethane acrylate.

[0009] S12: Polyisobutylene, styrene-isoprene-styrene block copolymer, C5 petroleum resin, and paraffin oil are mixed in an internal mixer. Then, sodium carboxymethyl cellulose, gelatin, and antioxidant 1010 are added, and mixing continues. Next, polydopamine-grafted polyurethane acrylate is added, and the mixture is mixed at 75°C for 5 minutes to obtain a mixed rubber compound. Finally, the mixed rubber compound is calendered and cured to obtain a continuous rubber sheet.

[0010] S2: Preparation of the central ring zone material: Under light-protected conditions, N-isopropylacrylamide and N,N'-methylenebisacrylamide were dissolved in deionized water, and then furan-functionalized gelatin was added. The mixture was stirred at 40-50°C until completely dissolved. Then the temperature was lowered to 30°C, silica gel powder was added, and the mixture was mechanically stirred and degassed to obtain the central ring zone slurry.

[0011] S3: Preparation of inner ring region material: In a light-proof, nitrogen-filled atmosphere, sulfobetaine methacrylate, acrylamide, N,N'-methylenebisacrylamide, and photoinitiator were completely dissolved in Tris-HCl buffer; then dopamine hydrochloride was added, and the mixture was magnetically stirred until completely dissolved. After standing, a colorless and transparent solution was obtained.

[0012] S4: Prepare a reverse microstructure release film by performing surface corona treatment on a PET base film, then coating and curing it with a release agent, coating it with UV resin and immediately contacting it with the nickel template of the reverse microporous array, and finally UV curing, demolding, and aging to obtain a reverse microstructure release film.

[0013] S5: Stoma baseplate adhesive preparation process: The continuous film prepared in S1 is cut into concentric rings using a mold and placed on the reverse microstructure release film prepared above to obtain the outer ring area adhesive ring; the middle ring area slurry prepared in S2 is heated to 75°C and then injected into the middle ring area position within the outer ring area adhesive ring, and cooled to room temperature; the colorless and transparent solution prepared in S3 is injected into the inner ring area, and then a metal mask is used to cover the product, exposing only the inner ring area, and irradiated with an ultraviolet light source. After preparation, a layer of polyethylene protective film is covered and cured to obtain the stoma baseplate adhesive.

[0014] Furthermore, the mixing parameters described in S12 are set as follows: temperature 100℃, duration 15min, and rotation speed 30rpm.

[0015] The parameters for the continued mixing described in S12 are: temperature 80℃, duration 10min, and rotation speed 30rpm.

[0016] The rolling mill described in S12 has the following parameter settings: upper roll temperature 80℃, middle roll temperature 70℃, lower roll temperature 60℃, and roll gap 0.8mm.

[0017] The curing process described in S12 has the following parameters: temperature 40℃, duration 24h.

[0018] Furthermore, the mechanical stirring described in S2 has the following parameter settings: rotation speed 2000 rpm, duration 2 min.

[0019] The degassing process described in S2 has the following parameters: vacuum degree -0.095MPa, duration 5min.

[0020] Furthermore, the static setting parameters described in S3 are: temperature 25°C, duration 15 minutes.

[0021] Furthermore, the curing process described in S4 has the following parameters: temperature 120°C, duration 1 minute.

[0022] The UV curing described in S4 has the following parameter settings: wavelength 395nm, intensity 800mW / cm². 2 Duration: 2 seconds.

[0023] The curing process described in S4 has the following parameters: temperature 25℃, relative humidity 45%, and duration 24h.

[0024] Furthermore, the irradiation described in S5 has the following parameter settings: wavelength 365nm, intensity 5-15mW / cm². 2 The duration is 30-90 seconds.

[0025] The curing process described in S5 has the following parameters: temperature 40℃, duration 24h.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides targeted solutions for the challenges of different regions through a three-zone gradient design. Working together, they achieve globally optimal adhesion, sealing, absorption, and re-adhesion performance.

[0027] 2. This invention utilizes mussel-inspired biochemistry and zwitterionic anti-fouling strategies in the inner ring region, combined with the physical adsorption of biomimetic microstructures, to ensure long-term adhesion stability in extremely humid environments and effectively prevent detachment.

[0028] 3. This invention utilizes the thermally reversible properties of the central ring area, enabling repeated positioning and pasting through simple cooling, which greatly improves the user experience and reduces waste. Attached Figure Description

[0029] Figure 1 This is a flowchart of the preparation process of an adhesive for stoma base plates.

[0030] Figure 2 This is a schematic diagram of the stoma baseplate adhesive finally prepared in Example 1: a is the outer ring area: providing peripheral anchoring; b is the middle ring area: absorbing a small amount of exudate and achieving repeated adhesion through thermal reversibility; c is the inner ring area: resisting high concentrations of exudate and maintaining adhesion; d is the recessed structure.

[0031] Figure 3 This is a comparison chart of the initial adhesion force, water absorption swelling rate, and peel strength of the stoma baseplate adhesives finally prepared in Examples 1-4 and Comparative Examples 1-2. Detailed Implementation

[0032] The following embodiments further explain and illustrate the technical solutions of the present invention. It should be specifically noted that each specific embodiment is a concretization and explanation of the technical solution and should not be considered as a limitation on the scope of protection of the present invention. Those skilled in the art still have the right to modify the technical solutions of these embodiments and make equivalent substitutions for some or all of the technical features, and these modifications or substitutions do not change the essence of the corresponding technical solutions, nor do they cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention.

[0033] This invention proposes an adhesive for a stoma baseplate and its preparation method. The inner ring region utilizes a composite hydrogel composed of a high proportion of mussel-inspired bio-adhesive and a zwitterionic polymer. The mussel-inspired bio-adhesive contains a large number of catechol-based adhesive groups, enhancing adhesion stability in wet environments. The zwitterionic polymer exhibits excellent anti-biofouling properties and can form a hydration layer on the gel surface to inhibit protein contamination. The middle ring region, through the properties of thermally reversible hydrogel and microporous silica gel, allows the baseplate to regain most of its adhesiveness after being removed under mild conditions, allowing for minor repositioning or removal for cleaning and reuse. The outer ring region employs a moderately modified conventional hydrocolloid adhesive, providing peripheral support and anchoring for the baseplate. This hydrocolloid adhesive forms a continuous and reliable adhesion to the skin surface. (See attached image.) Figure 1 The diagram shows the preparation process of an adhesive for a stoma baseplate, and its detailed technical solution is as follows: 1. Material preparation in the outer ring area 1.1 Preparation of polydopamine-grafted polyurethane acrylate Polycaprolactone diol was reacted with excess diisocyanate, followed by the addition of hydroxyethyl methacrylate and the dropwise addition of dibutyltin dilaurate as a catalyst. A polyurethane acrylate prepolymer was prepared at 70°C. The polyurethane acrylate prepolymer was dissolved in N,N-dimethylformamide solvent, and dopamine hydrochloride was added under nitrogen protection. The mixture was stirred to prepare polydopamine-grafted polyurethane acrylate.

[0034] 1.2 Raw material mass ratio Based on 40 parts of polyisobutylene (PIB) and 20 parts of styrene-isoprene-styrene block copolymer, 15-25 parts of C5 petroleum resin, 5-10 parts of polydopamine-grafted polyurethane acrylate, 10-20 parts of sodium carboxymethyl cellulose, 5-15 parts of gelatin, 8-20 parts of paraffin oil, and 0.5-1.5 parts of antioxidant 1010.

[0035] 1.3 Preparation Polyisobutylene, styrene-isoprene-styrene block copolymer, C5 petroleum resin, and paraffin oil were low-temperature mixed in an internal mixer to prevent degradation of the styrene-isoprene-styrene block copolymer. Then, sodium carboxymethyl cellulose, gelatin, and antioxidant 1010 were added, and mixing continued, with the addition occurring at a lower temperature to prevent pre-gelling of the hydrocolloid. Next, polydopamine-grafted polyurethane acrylate was added, and the mixture was mixed at 75°C for 5 minutes. This short-term low-temperature processing protected the catechol active groups, resulting in a mixed rubber compound. Finally, the mixed rubber compound was calendered and cured to obtain a continuous sheet. Calendering prevented bubble formation, and curing improved tack stability.

[0036] 2. Material preparation in the central ring area 2.1 Raw material mass ratio Based on 20 parts of N-isopropylacrylamide and 0.2 parts of N,N'-methylenebisacrylamide, 3-8 parts of furan-functionalized gelatin, 1-3 parts of diphenylmethane bismaleimide crosslinking agent, 10-30 parts of silica gel powder, and 50-70 parts of deionized water.

[0037] 2.2 Preparation Under light-protected conditions, N-isopropylacrylamide and N,N'-methylenebisacrylamide were dissolved in deionized water, and then furan-functionalized gelatin was added. The mixture was stirred at 40–50°C until completely dissolved. The temperature was then lowered to 30°C, and silica gel powder was added. Adding silica gel powder at 30°C prevents premature polymerization of N-isopropylacrylamide at higher temperatures. The mixture was mechanically stirred and degassed to obtain a slurry with a central ring zone. Mechanical stirring ensured high-precision, bubble-free mixing, guaranteeing the uniformity of the slurry. Degasting was necessary because the slurry had a high viscosity, and silica gel powder is a porous material that easily traps air bubbles. Otherwise, the density and appearance of the final colloid would be affected.

[0038] 3. Material preparation for the inner ring area 3.1 Raw material mass ratio Based on 25 parts of sulfobetaine methacrylate (SBMA), 1 part of dopamine hydrochloride, and 8 parts of acrylamide, 0.1-0.3 parts of N,N'-methylenebisacrylamide, 0.1-0.3 parts of photoinitiator, and 60-70 parts of Tris-HCl buffer (pH 8.5, 0.1 mol / L).

[0039] 3.2 Preparation In a light-protected, nitrogen-filled atmosphere, sulfobetaine methacrylate, acrylamide, N,N'-methylenebisacrylamide, and photoinitiator were completely dissolved in Tris-HCl buffer. In this alkaline environment, dissolved oxygen would induce the slow oxidation of dopamine, generating quinone active intermediates and their oligomers. Then, dopamine hydrochloride was added, and the mixture was magnetically stirred until completely dissolved. After standing, a colorless and transparent solution was obtained, ensuring that dopamine was effectively covalently incorporated into the polymer network. 4. Preparation of reverse microstructure release films 4.1 Preparation The PET base film is subjected to surface corona treatment to increase its surface tension; then it is coated and cured with a release agent to achieve clean peeling; then it is coated with UV resin and immediately contacted with the nickel template of the reverse microporous array; finally, it is UV cured, demolded, and aged to obtain a reverse microstructure release film.

[0040] 5. Stoma baseplate adhesive preparation process 5.1 Preparation of the outer ring area The continuous film prepared above is cut into concentric rings using a mold and placed on the reverse microstructure release film prepared above.

[0041] 5.2 Fill the middle ring area The prepared slurry in the middle ring area is heated to 75°C and then injected into the middle ring area within the outer ring rubber ring. It is then cooled to room temperature.

[0042] 5.3 Preparation of the inner ring region The colorless and transparent solution prepared above is injected into the inner ring region. Then, a metal mask is used to cover the product, exposing only the inner ring region. The inner ring region is irradiated with an ultraviolet light source to cause copolymerization and cross-linking reactions of the material, forming a strong gel network. After preparation, a layer of polyethylene protective film is applied and allowed to mature to obtain the stoma baseplate adhesive.

[0043] Example 1 A method for preparing an adhesive for an ostomy baseplate is as follows: Table 1 Main Raw Materials S1: Material preparation for the outer ring region.

[0044] S11: Polycaprolactone diol is reacted with excess diisocyanate, then hydroxyethyl methacrylate is added, and dibutyltin dilaurate catalyst is added dropwise to prepare a polyurethane acrylate prepolymer at 70°C; the polyurethane acrylate prepolymer is dissolved in N,N-dimethylformamide solvent, and dopamine hydrochloride is added under nitrogen protection and stirred to prepare polydopamine-grafted polyurethane acrylate.

[0045] S12: Polyisobutylene, styrene-isoprene-styrene block copolymer, C5 petroleum resin, and paraffin oil are mixed in an internal mixer with the following parameters: temperature 100℃, time 15 min, and speed 30 rpm. Then, sodium carboxymethyl cellulose, gelatin, and antioxidant 1010 are added, and mixing continues with the following parameters: temperature 80℃, time 10 min, and speed 30 rpm. Finally, polydopamine-grafted polyurethane acrylate is added, and the mixture is mixed at 75℃ for 5 min to obtain the mixed compound. Finally, the mixed rubber compound is calendered and cured to obtain a continuous rubber sheet. The calendering parameters are set as follows: upper roller temperature 80℃, middle roller temperature 70℃, lower roller temperature 60℃, and roller gap 0.8mm. The curing parameters are set as follows: temperature 40℃, curing time 24h. The mixture consists of 40 parts of polyisobutylene, 20 parts of styrene-isoprene-styrene block copolymer, 20 parts of C5 petroleum resin, 8 parts of polydopamine-grafted polyurethane acrylate, 15 parts of sodium carboxymethyl cellulose, 10 parts of gelatin, 14 parts of paraffin oil, and 1 part of antioxidant 1010.

[0046] S2: Preparation of the central ring zone material: Under light-protected conditions, N-isopropylacrylamide and N,N'-methylenebisacrylamide were dissolved in deionized water, and then furan-functionalized gelatin was added. The mixture was stirred at 45°C until completely dissolved. Then, the temperature was lowered to 30°C, silica gel powder was added, and the mixture was mechanically stirred and degassed to obtain the central ring zone slurry. The mechanical stirring parameters were set as follows: speed 2000 rpm, duration 2 min; degassed parameters were set as follows: vacuum degree -0.095 MPa, duration 5 min. The slurry consisted of 20 parts of N-isopropylacrylamide, 0.2 parts of N,N'-methylenebisacrylamide, 6 parts of furan-functionalized gelatin, 2 parts of diphenylmethane bismaleimide crosslinking agent, 20 parts of silica gel powder, and 60 parts of deionized water.

[0047] S3: Preparation of the inner ring region material: Under a light-proof, nitrogen-filled atmosphere, sulfobetaine methacrylate, acrylamide, N,N'-methylenebisacrylamide, and photoinitiator were completely dissolved in Tris-HCl buffer. Then, dopamine hydrochloride was added, and the mixture was magnetically stirred until completely dissolved. The solution was allowed to stand for 15 minutes at 25°C to obtain a colorless and transparent solution. The solution contained 25 parts of sulfobetaine methacrylate (SBMA), 1 part of dopamine hydrochloride, 8 parts of acrylamide, 0.2 parts of N,N'-methylenebisacrylamide, 0.2 parts of photoinitiator, and 65 parts of Tris-HCl buffer (pH 8.5, 0.1 mol / L).

[0048] S4: Preparation of the reverse microstructure release film: A PET base film is subjected to surface corona treatment, then coated and cured with a release agent. Next, a UV resin is coated and immediately brought into contact with the nickel template of the reverse microporous array. Finally, UV curing, demolding, and aging are performed to obtain the reverse microstructure release film. The curing parameters are set as follows: temperature 120℃, duration 1 min; UV curing parameters are set as follows: wavelength 395 nm, intensity 800 mW / cm². 2 Duration 2 seconds, curing parameters: temperature 25℃, relative humidity 45%, duration 24 hours.

[0049] S5: Stoma baseplate adhesive preparation process: The continuous film prepared in S1 is cut into concentric rings using a mold and placed on the prepared reverse microstructure release film to obtain the outer ring adhesive ring. The middle ring slurry prepared in S2 is heated to 75℃ and then injected into the middle ring area within the outer ring adhesive ring, and then cooled to room temperature. The colorless and transparent solution prepared in S3 is injected into the inner ring area, and then a metal mask is used to cover the product, exposing only the inner ring area. It is then irradiated with an ultraviolet light source. After preparation, a polyethylene protective film is applied, and the mixture is cured to obtain the stoma baseplate adhesive. The irradiation parameters are set as follows: wavelength 365nm, intensity 10mW / cm². 2 Duration 60s, curing parameters: temperature 40℃, duration 24h. Figure 2A schematic diagram of the adhesive for the stoma base plate: a is the outer ring zone: providing peripheral anchoring; b is the middle ring zone: absorbing small amounts of exudate and achieving re-adhesion through thermal reversibility; c is the inner ring zone: resisting high concentrations of exudate and maintaining adhesion; d is the recessed structure.

[0050] Example 2 The composition and preparation process are the same as in Example 1, except that: In the preparation process S12, there are 15 parts of C5 petroleum resin, 5 parts of polydopamine-grafted polyurethane acrylate, 10 parts of sodium carboxymethyl cellulose, 5 parts of gelatin, 8 parts of paraffin oil, and 0.5 parts of antioxidant 1010. The other components are the same.

[0051] In step S2 of the preparation process, the furan-functionalized gelatin is stirred at 40°C until completely dissolved, and the other steps are the same.

[0052] In preparation process S2, there are 3 parts of furan-functionalized gelatin, 1 part of diphenylmethane bismaleimide crosslinking agent, 10 parts of silica gel powder, and 50 parts of deionized water, with the other components being the same.

[0053] In the preparation process S3, there are 0.1 parts of N,N'-methylenebisacrylamide, 0.1 parts of photoinitiator, and 60 parts of Tris-HCl buffer, with other components being the same.

[0054] The irradiation intensity in step S5 of the preparation process is 5 mW / cm. 2 The irradiation time is 30 seconds, and the other steps are the same.

[0055] Example 3 The composition and preparation process are the same as in Example 1, except that: In the preparation process S12, there are 25 parts of C5 petroleum resin, 10 parts of polydopamine-grafted polyurethane acrylate, 20 parts of sodium carboxymethyl cellulose, 15 parts of gelatin, 20 parts of paraffin oil, and 1.5 parts of antioxidant 1010. The other components are the same.

[0056] In step S2 of the preparation process, the furan-functionalized gelatin is stirred at 50°C until completely dissolved, and the other steps are the same.

[0057] In preparation process S2, there are 8 parts of furan-functionalized gelatin, 3 parts of diphenylmethane bismaleimide crosslinking agent, 30 parts of silica gel powder, and 70 parts of deionized water, with other components being the same.

[0058] In the preparation process S3, there are 0.3 parts of N,N'-methylenebisacrylamide, 0.3 parts of photoinitiator, and 70 parts of Tris-HCl buffer, with other components being the same.

[0059] The irradiation intensity in step S5 of the preparation process is 15 mW / cm. 2 The irradiation time is 90 seconds, and the other steps are the same.

[0060] Example 4 The composition and preparation process are the same as in Example 1, except that: In the preparation process S12, there are 18 parts of C5 petroleum resin, 9 parts of polydopamine-grafted polyurethane acrylate, 12 parts of sodium carboxymethyl cellulose, 13 parts of gelatin, 10 parts of paraffin oil, and 0.9 parts of antioxidant 1010. The other components are the same.

[0061] In step S2 of the preparation process, the furan-functionalized gelatin is stirred at 40°C until completely dissolved, and the other steps are the same.

[0062] In the preparation process S2, there are 4 parts of furan-functionalized gelatin, 1.5 parts of diphenylmethane bismaleimide crosslinking agent, 25 parts of silica gel powder, and 65 parts of deionized water, with the other components being the same.

[0063] In the preparation process S3, there are 0.15 parts of N,N'-methylenebisacrylamide, 0.25 parts of photoinitiator, and 63 parts of Tris-HCl buffer, with other components being the same.

[0064] The irradiation intensity in step S5 of the preparation process is 13 mW / cm. 2 The irradiation time is 45 seconds, and the other steps are the same.

[0065] Comparative Example 1 The composition and preparation process are the same as in Example 1, except that: In step S4 of the preparation process, the biomimetic microstructure release membrane is removed and replaced with a smooth release membrane; the other steps remain the same.

[0066] Comparative Example 2 The composition and preparation process are the same as in Example 1, except that: In step S5 of the preparation process, the partitioning preparation is removed, and the materials are mixed completely. The other steps are the same.

[0067] Based on Examples 1-4 and Comparative Examples 1-2, samples of the adhesive used in the final prepared stoma baseplate were taken for initial adhesion, peel strength, and number of re-adhesion tests, referring to standard GB / T 2792-2014 "Test Method for Peel Strength of Adhesive Tape".

[0068] Based on Examples 1-4 and Comparative Examples 1-2, samples of the adhesive used in the final prepared stoma baseplate were taken and tested for adhesion time in a wet environment, referring to standard GB / T 4851 "Test Method for Adhesion Holding Power of Pressure Sensitive Adhesive Tapes".

[0069] Based on Examples 1-4 and Comparative Examples 1-2, samples of the adhesive from the final prepared stoma baseplate were taken for water absorption and swelling rate testing, referring to standard GB / T 20405.5-2025 "Urine Absorbent Polyacrylate Powder for Incontinence - Part 5: Determination of water absorption rate by gravimetric method in saline solution".

[0070] The specific test results are shown in Table 2. Figure 3 As shown: Table 2 Comparison of core performance of Examples 1-4 and Comparative Examples 1-2 The comparison results above show that Example 1 has the best overall performance. Polydopamine-grafted polyurethane acrylate provides wet adhesion; sodium carboxymethyl cellulose and gelatin form a highly efficient water-absorbing and water-locking network, which manages exudate without excessive expansion leading to failure. The zoned design ensures strong adhesion in the outer ring, water absorption and buffering in the middle ring, and biocompatibility in the inner ring, maximizing synergistic effects. This demonstrates that Example 1 successfully solves the problems of poor adhesion stability and insufficient re-adhesion performance in wet environments. Example 2, with reduced component dosage, slightly decreased wet holding power and cohesion, shortened holding time, and reduced the number of re-adhesions by one. Example 3, with increased component dosage, slightly increased water absorption and swelling rate, which may lead to increased local pressure and affect the adhesion time in wet environments. Example 4's parameters fall between... Randomly selected examples still performed well, but did not reach the optimal balance point of Example 1. Examples 2 to 4 showed slightly lower overall performance than Example 1, indicating that excellent adsorption effects were still achieved under a wide range of parameter variations. Comparative Example 1 used a smooth release film with a flat colloidal surface, resulting in a sharp decrease in the number of re-adhesion cycles to only 2. This was because the flat surface underwent irreversible plastic deformation and cohesive failure upon the first peel. Adhesion in a wet environment also decreased due to the lack of microstructure anchoring effect, making it more prone to overall slippage and detachment under liquid wetting. Comparative Example 2 mixed all functional materials, resulting in very low initial adhesion. This was because the strong adhesion system was incompatible with the hydrophilic gel system, forming a defective interface. The water absorption and swelling rate was extremely high and uncontrollable, leading to rapid material structure disintegration. Adhesion was extremely short-lived, making effective adhesion impossible.

[0071] In summary, it is clear from the above embodiments and comparative examples that the stoma baseplate adhesive provided by the present invention is significantly superior to traditional solutions in terms of initial adhesion force, adhesion time in wet environments, water absorption and swelling rate, and number of re-adhesion times. This is attributed to the optimized material formulation, innovative polydopamine grafting technology, biomimetic microstructure surface, and core partitioned structure design, thereby solving the problems of poor adhesion stability in wet environments and insufficient re-adhesion performance.

Claims

1. An adhesive for a stoma base plate, characterized in that: The stoma baseplate adhesive consists of an inner ring area adjacent to the stoma, a middle ring area, and an outer ring area. The adhesive contact surface has a biomimetic microstructure, which generates negative pressure to assist adsorption when applied to the skin, enhancing the overall adhesion. The inner ring area can resist the invasion of high concentrations of exudate and maintain adhesion. The middle ring area can absorb a small amount of exudate while achieving a re-application function. The outer ring area adheres to the relatively dry skin surface, providing stable peripheral anchoring.

2. The stoma baseplate adhesive according to claim 1, characterized in that: The inner ring region is a composite hydrogel formed by mussel biomimetic adhesive and zwitterionic polymer. The specific raw materials are as follows: based on 25 parts of sulfobetaine methacrylate, 1 part of dopamine hydrochloride, and 8 parts of acrylamide, 0.1-0.3 parts of N,N'-methylenebisacrylamide, 0.1-0.3 parts of photoinitiator, and 60-70 parts of Tris-HCl buffer.

3. The stoma baseplate adhesive according to claim 1, characterized in that: The central ring region is an interpenetrating network layer formed by thermally reversible hydrogel and microporous silica gel. The specific raw materials for preparation are as follows: based on 20 parts of N-isopropylacrylamide and 0.2 parts of N,N'-methylenebisacrylamide, 3-8 parts of furan-functionalized gelatin, 1-3 parts of diphenylmethane bismaleimide crosslinking agent, 10-30 parts of silica gel powder, and 50-70 parts of deionized water.

4. The stoma baseplate adhesive according to claim 1, characterized in that: The outer ring region is a modified hydrocolloid adhesive layer. The specific raw materials for preparing the hydrocolloid adhesive layer are as follows: based on 40 parts of polyisobutylene and 20 parts of styrene-isoprene-styrene block copolymer, 15-25 parts of C5 petroleum resin, 5-10 parts of polydopamine-grafted polyurethane acrylate, 10-20 parts of sodium carboxymethyl cellulose, 5-15 parts of gelatin, 8-20 parts of paraffin oil, and 0.5-1.5 parts of antioxidant 1010.

5. The stoma baseplate adhesive according to claim 1, characterized in that: The biomimetic microstructure consists of micron-sized semi-circular pits, which are spaced apart by microchannels to create negative pressure and enhance breathability when the parts are fitted together.

6. The method for preparing the stoma baseplate adhesive according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Material preparation in the outer ring region; S11: Polycaprolactone diol is reacted with excess diisocyanate, then hydroxyethyl methacrylate is added, and dibutyltin dilaurate is added dropwise as a catalyst to prepare a polyurethane acrylate prepolymer at 70°C; the polyurethane acrylate prepolymer is dissolved in N,N-dimethylformamide solvent, and dopamine hydrochloride is added under nitrogen protection and stirred to prepare polydopamine-grafted polyurethane acrylate; S12: Polyisobutylene, styrene-isoprene-styrene block copolymer, C5 petroleum resin and paraffin oil are mixed in an internal mixer; then sodium carboxymethyl cellulose, gelatin and antioxidant 1010 are added and the mixture is continued; then polydopamine-grafted polyurethane acrylate is added and the mixture is mixed at 75°C for 5 minutes to obtain a mixed rubber compound; finally, the mixed rubber compound is calendered and cured to obtain a continuous rubber sheet. S2: Preparation of the central ring zone material: N-isopropylacrylamide and N,N'-methylenebisacrylamide were dissolved in deionized water under light-protected conditions, and then furan-functionalized gelatin was added. The mixture was stirred at 40-50°C until completely dissolved. Then the temperature was lowered to 30°C, silica gel powder was added, and the mixture was mechanically stirred and degassed to obtain the central ring zone slurry. S3: Preparation of inner ring region material: In a light-proof, nitrogen-filled atmosphere, sulfobetaine methacrylate, acrylamide, N,N'-methylenebisacrylamide, and photoinitiator were completely dissolved in Tris-HCl buffer; then dopamine hydrochloride was added, and the mixture was magnetically stirred until completely dissolved. After standing, a colorless and transparent solution was obtained. S4: Prepare a reverse microstructure release film by performing surface corona treatment on a PET base film, then coating and curing it with a release agent, then coating it with UV resin and immediately contacting it with the nickel template of the reverse micropore array, and finally UV curing, demolding, and curing to obtain a reverse microstructure release film. S5: Stoma baseplate adhesive preparation process: The continuous film prepared in S1 is cut into concentric rings using a mold and placed on the reverse microstructure release film prepared in S4 to obtain the outer ring area adhesive ring; the middle ring area slurry prepared in S2 is heated to 75℃ and then injected into the middle ring area position inside the outer ring area adhesive ring, and cooled to room temperature; the colorless and transparent solution prepared in S3 is injected into the inner ring area, and then a metal mask is used to cover the product, exposing only the inner ring area, and irradiated with an ultraviolet light source. After preparation, a layer of polyethylene protective film is covered and cured to obtain the stoma baseplate adhesive.

7. The method for preparing a stoma baseplate adhesive according to claim 6, characterized in that: The mixing parameters described in S12 are: temperature 100℃, duration 15min, and rotation speed 30rpm. The parameters for the continued mixing described in S12 are: temperature 80℃, duration 10min, and rotation speed 30rpm. The rolling mill described in S12 has the following parameter settings: upper roll temperature 80℃, middle roll temperature 70℃, lower roll temperature 60℃, and roll gap 0.8mm; The curing process described in S12 has the following parameters: temperature 40℃, duration 24h.

8. The method for preparing a stoma baseplate adhesive according to claim 6, characterized in that: The degassing process described in S2 has the following parameter settings: vacuum degree -0.095MPa, duration 5min; The static setting parameters for S3 are: temperature 25℃, duration 15min.

9. The method for preparing a stoma baseplate adhesive according to claim 6, characterized in that: The curing process described in S4 has the following parameters: temperature 120°C, duration 1 min. The UV curing described in S4 has the following parameter settings: wavelength 395nm, intensity 800mW / cm². 2 Duration: 2 seconds; The curing process described in S4 has the following parameters: temperature 25℃, relative humidity 45%, and duration 24h.

10. The method for preparing a stoma baseplate adhesive according to claim 6, characterized in that: The irradiation described in S5 has the following parameters: wavelength 365nm, intensity 5-15mW / cm². 2 Duration: 30–90 seconds; The curing process described in S5 has the following parameters: temperature 40℃, duration 24h.

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