Modified Polyolefin Aqueous Dispersion for Low-Temperature Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aqueous dispersions of modified polyolefins face challenges in achieving excellent adherence and peel strength to non-polar substrates under low-temperature, short-time baking conditions due to the need for high heat to remove water, which reduces resin adherence and peel strength.
Innovation Solution
An aqueous dispersion of modified polyolefin with carboxyl and amide groups derived from α, β-unsaturated carboxylic anhydride and an amino compound, combined with a basic compound, exhibits improved adherence and peel strength by graft-copolymerizing polyolefins with these components and using a phase inversion emulsification method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aqueous dispersion is used, then environmental friendliness is improved, but adherence to non-polar substrates deteriorates under low-temperature baking
Solution Approach 1:
The patent uses a composite resin system combining polyolefin resin (for adhesion to non-polar substrates) with acrylic resin or polyester resin (for coating performance). This composite approach allows the aqueous dispersion to maintain environmental benefits while achieving sufficient adherence through the synergistic effect of different resin components, where polyolefin provides substrate bonding and the other resins provide film formation and adhesion.
Solution Approach 2:
The patent changes the chemical composition parameters of the resin system by incorporating specific ratios of polyolefin resin (5-50 mass%), acrylic resin (30-60 mass%), and polyester resin (10-40 mass%). It also controls the glass transition temperature (Tg) of the coating film within -50°C to 0°C through selective resin combinations and adjusts basic compound content to 0.1-5 mass% to optimize both environmental compatibility and adherence under low-temperature baking conditions.
2Object-generated harmful factors
If aqueous dispersion is used, then solvent emissions are reduced, but peel strength deteriorates due to insufficient heat for water removal
Solution Approach 1:
The patent adjusts the glass transition temperature (Tg) of the coating film to a specific range of -50°C to 0°C by carefully selecting and proportioning resin components. This Tg optimization allows the coating to remain flexible during low-temperature baking, accommodating the drying process without compromising peel strength. The controlled Tg ensures that the coating maintains adequate adhesion even when baked at temperatures sufficient for water evaporation.
Solution Approach 2:
The composite resin system combines polyolefin resin with acrylic or polyester resins to achieve balanced performance. The acrylic or polyester resin components contribute to film formation and adhesion properties that compensate for the limitations of aqueous drying, while the polyolefin ensures substrate bonding. This composite structure enables the coating to achieve sufficient peel strength through low-temperature baking without solvent emissions.
3Use of energy by stationary object
If low-temperature baking is used, then energy consumption is reduced, but resin melting and adherence deteriorate
Solution Approach 1:
The patent optimizes the glass transition temperature (Tg) of the coating film to -50°C to 0°C, which is significantly lower than traditional coatings. This parameter change allows the coating to remain in a rubbery state during low-temperature baking, facilitating film formation and adhesion at reduced temperatures. The low Tg ensures that the resin remains sufficiently mobile to adhere to the substrate even when baked at energy-saving temperatures, eliminating the need for high-temperature curing.
Solution Approach 2:
The patent creates local quality differences within the coating system by using polyolefin resin specifically for substrate interaction (providing local adhesion to non-polar surfaces) while using acrylic or polyester resins for bulk coating properties. This functional differentiation allows the coating to achieve adequate adherence through low-temperature baking, as the polyolefin component maintains substrate bonding capability at lower temperatures while the other resins provide film 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 modified polyolefin dispersion achieves excellent adherence, water resistance, and high peel strength to polyolefin substrates even under 80°C baking conditions, suitable for paints, inks, adhesives, and primers.
Implementation Method 1
the carboxyl group and the amide group of the modified polyolefin (A) are respectively derived from an α, β-unsaturated carboxylic anhydride (B) and an amino compound having at least one active hydrogen on a nitrogen atom (C)
Implementation Method 2
using a phase inversion emulsification method
Implementation Method 3
the aqueous dispersion contains a basic compound (D)
Data Source
AI summary
The present invention relates to an aqueous dispersion of a modified polyolefin that exhibits excellent adherence (adhesion) and water resistance, as well as a high level of peel strength on a polyolefin substrate under baking conditions of 80° C. for a short time, and have the following characteristics (I), (II), and (III): (I) a modified polyolefin (A) has a carboxyl group and an amide group; (II) the carboxyl group and the amide group of the modified polyolefin (A) are respectively derived from an α, β-unsaturated carboxylic anhydride (B) and an amino compound having at least one active hydrogen on a nitrogen atom (C), the amino compound (C) having an aliphatic hydrocarbon or aromatic hydrocarbon skeleton; and (iii) the aqueous dispersion contains a basic compound (D).