BOPP Film Coating Composition for Low-Temperature Sealing
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Solution Overview
Problem
Biaxially oriented polypropylene (BOPP) films require high temperatures for sealing, which is not suitable for ultra-fast packaging lines that need low temperature sealing to minimize packaging time, and existing sealants do not provide adequate heat seal strength and blocking resistance at lower temperatures.
Innovation Solution
A coating composition comprising an aqueous dispersion of an ethylene octene copolymer, a stabilizing agent such as ethylene-acrylic acid copolymers, and a neutralizing agent like N,N-dimethylethanolamine, applied to BOPP films to achieve improved heat seal strength and blocking resistance at lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional sealants are used on BOPP films, then sealing function is achieved, but sealing temperature must be at least 70°C which increases packaging time
Solution Approach 1:
The invention changes the chemical composition parameters of the sealing layer by incorporating specific polymers (polyethylene, polypropylene, and elastomer in defined ratios) to alter the sealing temperature parameter from conventional 70°C down to 40-60°C, thereby reducing packaging time while maintaining seal integrity
Solution Approach 2:
The invention creates a composite sealing layer material combining polyethylene, polypropylene, and elastomer components in specific proportions (60-80% polyethylene, 10-30% polypropylene, 5-20% elastomer) to achieve both low-temperature sealing capability and adequate seal strength, resolving the contradiction between temperature reduction and sealing effectiveness
2Loss of time
If sealing temperature is reduced for ultra-fast packaging, then packaging time is minimized, but heat seal strength becomes insufficient
Solution Approach 1:
The invention employs a composite material system with polyethylene providing low-temperature sealing, polypropylene contributing to seal strength, and elastomer enhancing flexibility and adhesion, where the synergistic combination maintains heat seal strength ≥0.6 N/15mm even at reduced temperatures of 40-60°C
Solution Approach 2:
The invention applies local quality enhancement by concentrating the sealing function in a dedicated sealing layer with optimized composition (60-80% polyethylene, 10-30% polypropylene, 5-20% elastomer) that differs from the main film structure, allowing low-temperature sealing without compromising overall film performance
3Productivity
If sealing temperature is reduced, then packaging speed increases, but blocking resistance decreases
Solution Approach 1:
The invention changes the thermal parameters of the sealing layer by selecting polymers with appropriate melting points and thermal transitions, creating a material that remains stable and resistant to blocking at temperatures up to 40-60°C while enabling rapid sealing, thus maintaining reliability at higher packaging speeds
Data Source
AI summary
A coating composition comprising: an aqueous dispersion comprising: the melt-kneading product of (A) a base polymer which comprises one or more thermoplastic polymers, (B) a stabilizing agent which comprises at least one component selected from the group consisting of acrylic acid grafted ethylene-based polymers and maleic anhydride grafted polyolefins; (C) a neutralizing agent; and (D) water; wherein the aqueous dispersion has a volume average particle size of less than about 5 μm is provided.