I. Market Explosion Background and Upgrade of Core Requirements In 2026, the global advanced medical dressing market will witness an annual growth rate exceeding 20%. Driven by rising healthcare demands and the strong momentum of domestic substitution for imported goods, the domestic market is poised for leapfrog growth. Stock prices of leading enterprises like Zhende Medical have risen sharply, and the core driving force behind this market dividend is the continuous advancement of medical technology and consumption upgrading. Consequently, the technical requirements for adhesives used in medical tapes and dressings have upgraded from basic bonding to a multidimensional demand of "Safety + Functionality + Experience": · Safety Bottom Line: Products must comply with China's GB 6675, US FDA, and EU MDR relevant standards. Excellent biocompatibility is required, with zero heavy metals, allergenic substances, or residual solvents. The material must fully support aseptic manufacturing processes and high-temperature sterilization treatments. · Functional Adaptation: Wound dressings must be breathable to prevent heat rashes; medical patches must offer high drug loading capabilities with controllable drug release; sports tapes must stay securely attached without peeling off; and transparent products must guarantee high light transmittance to allow continuous wound monitoring. · Core Experience: Low allergenicity serves as the foundation to prevent adverse skin reactions such as redness and itching. Concurrently, the adhesive layer must be easy to peel off without leaving any residue, ensuring zero skin irritation during long-term wear. As the core base material of medical hot-melt pressure-sensitive adhesives (HMPSA), SIS has become the mainstream choice in the market due to its well-balanced advantages in tack and holding power. The selection of its specific grades directly determines the final competitiveness of the end products. II. Selection of Core SIS/SEBS Grades and Scenario Matching 1. Balanced Grade: YH-1125 · Core Characteristics: Well-balanced tack and peel strength, high cohesive strength, outstanding anti-migration performance, residue-free removal after peeling, excellent compatibility with medical-grade additives, and high flexibility in formulation adjustments. · Adapted Products: Edge sealing for adult incontinence products, long-term wear fixation patches, and removable medical tapes. Ideally suited for conventional medical scenarios requiring rigorous safety and high stability. · Performance Highlights: Low-allergenicity formulations are easy to implement. It satisfies the basic requirements of most medical dressings through simple optimization, offering an outstanding cost-performance ratio. It is the preferred choice for mass-produced products. 2. High-Tack Transparent Grade: YH-1126 · Core Characteristics: Outstanding initial tack for rapid bonding to skin or substrates, clean die-cutting edges, excellent compatibility with tackifying resins, high transparency of the prepared adhesive, and strong compatibility with drug loading. · Adapted Products: Infusion patches, bottle-mouth tapes, disposable bandages, and other rapid-bonding dressings, as well as transparent medical tapes and high-end anti-counterfeiting patches. · Performance Highlights: Excellent processing fluidity enhances production line efficiency. Its light transmittance reaches over 85%, ensuring wound observation is never obstructed, thus perfectly satisfying the needs of visualized medical care. 3. High-Strength Structural Grade: YH-1105 · Core Characteristics: Low styrene content leads to low hardness, while its pure tri-block structure provides high cohesive strength. It balances pressure-sensitive properties and tack, reducing the overall formulation hardness while guaranteeing robust bonding reliability. · Adapted Products: Sanitary structural adhesives, high-strength medical tapes, and heavy-duty dressing fixation patches. It is tailor-made for scenarios requiring long-term load-bearing capabilities or ultra-strong bonding. · Performance Highlights: Eliminates the oil-bleeding risks associated with excessive diblocks. It boasts strong structural stability, can withstand repeated bending, and is highly resistant to debonding. 4. High-Tack Structural Grade: YH-1106 · Core Characteristics: High tri-block structure ensures high cohesive strength, while containing a specific proportion of diblocks. Compared to YH-1105, it delivers superior initial tack and faster bonding activation. · Adapted Products: Sanitary structural adhesives, high-strength medical tapes, and dressings requiring rapid setting, successfully reconciling structural stability with bonding efficiency. · Performance Highlights: Exhibits excellent synergy between initial tack and cohesive strength. It removes the need for extra tackifiers, simplifying the formulation while simultaneously minimizing the risk of allergenicity. 5. Function-Enhanced Grade: SEBS YH-501T · Core Characteristics: Highly stable molecular structure, exceptional aging resistance, and excellent blendability with SIS. It significantly enhances the cohesion of the adhesive layer and its drug-loading regulation capabilities. · Adapted Products: Medicated plasters, long-acting sustained-release patches, and other medical patches with strict requirements on drug loading capacity and release rate, as well as sports tapes for outdoor use. · Performance Highlights: When compounded with SIS, the drug loading capacity can be boosted by more than 30%. It effectively retards drug release through molecular chain adsorption, while upgrading weather resistance to extend product shelf life. III. Formulation Optimization Strategies: Blending and Compounding Techniques 1. Multi-Grade SIS Blending · Rapid Bonding + Low Residue Requirements: Blending YH-1126 (high tack) and YH-1125 (high cohesion) at a 6:4 ratio balances bonding efficiency with application safety. · High Strength + Low Hardness Requirements: Blending YH-1105 and YH-1106 at a 5:5 ratio achieves an optimal equilibrium between structural strength and skin compliance. · Core Blending Principle: The primary grade should account for 60%–80%, with the auxiliary grade used strictly for fine-tuning performance. This prevents ratio imbalances that cause a sharp decay in initial tack or cohesive properties. 2. SIS and SEBS Compounding · Drug Loading and Sustained Release Requirements: Compounding core SIS grades (such as YH-1126) with SEBS YH-501T at a 7:3 ratio ensures immediate pressure-sensitive tack while increasing drug loading capacity and retarding the drug release rate. · Aging Resistance Requirements: Incorporating 10%–20% of YH-501T utilizes its saturated molecular structure to fortify the weather resistance of the adhesive layer, thereby extending the product's storage life. · Compounding Precautions: The proportion of SEBS must be strictly controlled below 30% to avoid excessively compromising the pressure-sensitive properties and melt fluidity of the SIS base. 3. Optimization of Functional Additives · Breathability & Heat Rash Prevention: Adding 3%–5% hydrophilic nano-SiO2 constructs a multi-level breathable network, boosting the moisture vapor transmission rate (MVTR) by over 40%. · Low-Allergenicity Reinforcement: Selecting medical-grade hydrogenated rosin glycerol ester as the tackifier, paired with 0.3%–0.5% composite antioxidant, effectively eliminates irritating substance residues. · Sterilization Compatibility: Formulations must strictly avoid low-boiling-point additives to guarantee the material can withstand high-temperature sterilization at 121°C without generating any hazardous substances.