Radial Styrene Block Copolymer Adhesive Low-Temperature Bonding
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Solution Overview
Problem
Existing hot-melt adhesive agents for disposable products, such as paper diapers and napkins, face challenges in maintaining adhesiveness at low temperatures while avoiding the deterioration of heat resistance and material costs, particularly when using thin polyethylene films and nonwoven fabrics.
Innovation Solution
A hot-melt adhesive agent comprising a thermoplastic block copolymer with a radial type styrene block copolymer, a tackifier resin, and a plasticizer, specifically designed to have a styrene content of 35-45% and a diblock content of 50-90%, with a viscosity of not more than 250 mPa·s at 25°C, allowing for low-temperature application and improved adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of base polymer is decreased to increase the amount of plasticizer to lower viscosity, then the viscosity is reduced and low-temperature application becomes possible, but the balance between adhesiveness to polyethylene film and retention force deteriorates and the softening point is excessively lowered
Solution Approach 1:
The patent changes the molecular structure parameters of the base polymer from linear to radial type, and adjusts the styrene content (35-45%) and diblock content (50-90%) to achieve the desired balance between low viscosity and adequate retention force without excessively lowering the softening point
Solution Approach 2:
The patent creates a composite adhesive system combining radial type styrene block copolymer with specific styrene content range and diblock content range, tackifier resin, and plasticizer in optimized proportions to achieve synergistic effects that balance viscosity, adhesiveness, and retention force
2Temperature
If a low viscosity hot-melt adhesive agent is used to improve workability and environmental aspect, then the viscosity is reduced, but the adhesiveness at low temperature is insufficient
Solution Approach 1:
The patent optimizes the styrene content (35-45%) and diblock content (50-90%) parameters of the radial type styrene block copolymer to achieve a unique combination of low viscosity and high low-temperature adhesiveness that cannot be obtained by simply adjusting polymer-plasticizer ratios
Solution Approach 2:
The patent enhances the local adhesive quality at the polymer interface through the specific radial structure and compositional parameters, creating superior interfacial bonding characteristics that provide excellent low-temperature adhesiveness while maintaining low viscosity
3Quantity of substance
If the polyethylene film is thinned to reduce material costs and improve flexibility, then the material cost is reduced and flexibility is improved, but the heat resistance deteriorates and high-temperature application causes melting or wrinkle formation
Solution Approach 1:
The patent changes the application temperature parameter from high temperature (≥150°C) to low temperature (≤140°C) by using the radial type styrene block copolymer with optimized composition, thereby enabling safe application on thinned polyethylene films without causing melting or wrinkle formation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The adhesive agent achieves excellent adhesiveness and retention force at low temperatures, preventing peeling of components even in winter conditions, while maintaining a balance between tack and retention force, and is suitable for use in disposable products like paper diapers and napkins.
Implementation Method 1
a radial type styrene block copolymer having a styrene content of 35 to 45% by weight and a diblock content of 50 to 90% by weight, and having a viscosity at 25° C. as 25% (by weight) toluene solution of not more than 250 mPa·s
Implementation Method 2
The hot-melt adhesive agent according to the present invention has excellent adhesiveness at low temperature, and is excellent in balance between tack and retention force (cohesive force)
Implementation Method 3
the hot-melt adhesive agent according to the present invention is excellent in balance between tack and retention force (cohesive force), and is capable of strong bonding at low temperature
Data Source
AI summary
Problem to be solved of the present invention is to provide a hot-melt adhesive agent which is capable of applying at low temperature, has an excellent adhesiveness at low temperature, and a disposable product obtained by employing the hot-melt adhesive agent. Means for solving the problem is a hot-melt adhesive agent comprised of a thermoplastic block copolymer (A) which is a copolymer of vinyl class aromatic hydrocarbons and conjugated diene compounds, wherein the thermoplastic block copolymer (A) comprises a radial type styrene block copolymer having a styrene content of 35 to 45% by weight and a diblock content of 50 to 90% by weight, and having a viscosity at 25° C. as a 25% (by weight) toluene solution of not more than 250 mPa·s (A1).