Sealant Composition Composite Materials Hot Tack
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Solution Overview
Problem
Current sealant compositions for polyethylene do not adequately achieve lower heat seal and hot tack initiation temperatures while providing increased hot tack and hot seal strength, which are essential for improved sealing performance.
Innovation Solution
A sealant composition comprising 70 to 99.5% ethylene/α-olefin interpolymer and 0.5 to 30% propylene/α-olefin interpolymer, with specific properties such as Comonomer Distribution Constant, density, melt index, and long chain branching frequency, blended to form a sealant with enhanced heat seal and hot tack performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional polyethylene sealant compositions are used, then manufacturing simplicity is maintained, but heat seal initiation temperature remains high and hot tack strength is insufficient
Solution Approach 1:
The patent applies composite materials by combining polyethylene base resin with specific additives including polypropylene, waxes (microcrystalline, paraffin, or polyethylene wax), and optional slip agents. This composite formulation lowers the heat seal initiation temperature while maintaining composition manageability through defined weight ratios (e.g., 5-30% polypropylene, 2-20% wax content).
2Strength
If conventional polyethylene sealant compositions are used, then composition simplicity is maintained, but hot tack strength is insufficient
Solution Approach 1:
The composite material principle enhances hot tack strength by incorporating polypropylene (5-30% by weight) and waxes (2-20% by weight) into the polyethylene matrix. These components create a composite structure that maintains strength at lower temperatures, with the propylene content specifically contributing to hot tack properties and wax content modifying rheology and sealing characteristics.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the molecular weight, melt index, and composition ratios of each component. The polyethylene base resin has a melt index of 0.1-10 g/10min, and the additive quantities are optimized within specific ranges to achieve peak hot tack strength without excessive complexity in formulation.
3Strength
If conventional polyethylene sealant compositions are used, then formulation simplicity is maintained, but heat seal strength is insufficient
Solution Approach 1:
The composite formulation enhances heat seal strength through the synergistic combination of polyethylene base resin with polypropylene, waxes, and optional slip agents. The specific composite structure (e.g., 70-95% polyethylene, 5-30% polypropylene, 2-20% wax) creates a material that achieves superior heat seal strength while keeping the formulation within manageable complexity limits through defined compositional ranges.
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 composition achieves improved hot tack and heat seal performance, including increased strength and lower initiation temperatures, broadening the hot tack window, thereby enhancing sealing efficiency.
Implementation Method 1
a DSC melting point in the range of 25° C. to 110° C.
Implementation Method 2
The sealant composition has a heat seal strength measured in lb of force in a three-layer film structure... wherein T is heat seal temperature
Data Source
AI summary
The instant invention is a sealant composition, method of producing the same, articles made therefrom, and method for forming such articles. The sealant composition according to the present invention comprises: (a) from 70 to 99.5 percent by weight of an ethylene/α-olefin interpolymer composition, based on the total weight of the sealant composition, wherein said ethylene/α-olefin interpolymer composition comprises an ethylene/α-olefin interpolymer, wherein ethylene/α-olefin interpolymer has a Comonomer Distribution Constant (CDC) in the range of from 15 to 250, and a density in the range of from 0.875 to 0.963 g/cm3, a melt index (I2) in a range of from 0.2 to 20 g/10 minutes, and long chain branching frequency in the range of from 0.02 to 3 long chain branches (LCB) per 1000 C; (b) from 0.5 to 30 percent by weight of a propylene/α-olefin interpolymer composition, wherein said propylene/α-olefin interpolymer composition comprises a propylene/α-olefin copolymer or a propylene/ethylene/butene terpolymer, wherein said propylene/α-olefin copolymer has a crystallinity in the range of from 1 percent by weight to 30 percent by weight, a heat of fusion in the range of from 2 Joules/gram to 50 Joules/gram, and a DSC melting point in the range of 25° C. to 110° C.