Polyolefin Coating Composition for Food Container Resistance

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Solution Overview

Problem

Existing coating compositions fail to simultaneously provide desirable mechanical and chemical resistance properties and appearance for certain applications, such as food and beverage containers, while also being cost-effective and environmentally friendly.

Innovation Solution

A coating composition comprising an aqueous dispersion with a high density polyethylene base polymer, maleic anhydride functionalized polyethylene, a polymeric stabilizing agent, and a maleic anhydride modified polyethylene wax, along with a crosslinker, which is applied to a substrate and cured to form a durable and resistant coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional coating compositions are used, then application is simple, but mechanical and chemical resistance properties are insufficient

Engineering Contradiction:
Improvemechanical and chemical resistanceVSAvoidcoating composition complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent employs a composite coating composition comprising polyolefin particles (40-80 wt%), reactive diluent (10-30 wt%), and crosslinking agent (5-20 wt%). This multi-component system combines the chemical resistance of polyolefin with the adhesion and crosslinking properties of the reactive diluent and crosslinking agent, achieving superior mechanical and chemical resistance that cannot be obtained with single-material coatings.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes by controlling the particle size distribution of polyolefin (0.1-10 μm), the molecular weight of crosslinking agent (1000-100,000 g/mol), and the curing temperature (50-150°C). These parameter optimizations enable the coating to achieve desired mechanical properties and chemical resistance while maintaining processability and adhesion to substrates.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high performance coating materials are used, then mechanical and chemical resistance is improved, but cost increases

Engineering Contradiction:
Improvecoating performance reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs readily available, cost-effective materials such as common polyolefin resins (LDPE, HDPE, LLDPE) and standard crosslinking agents. These materials can be sourced from conventional suppliers without requiring specialized or expensive components, thereby achieving reliable coating performance at competitive manufacturing costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent optimizes the weight ratio parameters of the coating components (polyolefin:reactive diluent:crosslinking agent) to achieve the desired performance-to-cost balance. By adjusting these ratios within specified ranges, the formulation maximizes the contribution of each component to coating reliability while minimizing the total material cost.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If traditional coating compositions are used, then formulation is simple, but appearance quality is insufficient

Engineering Contradiction:
Improveappearance qualityVSAvoidcoating composition complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by incorporating polyolefin particles with specific size ranges (0.1-10 μm) to achieve uniform dispersion and smooth surface appearance. The controlled particle size distribution ensures that the coating forms a homogeneous film without visible defects, while the reactive diluent and crosslinking agent provide localized adhesion enhancement at the substrate-coating interface.

Inventive Principle:
Principle #3Local quality

4Reliability

If conventional coatings are applied to metal substrates, then application is straightforward, but adhesion under acidic conditions is poor

Engineering Contradiction:
Improveadhesion under acidic conditionsVSAvoidcoating system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a reactive diluent as an intermediary component that facilitates adhesion between the polyolefin coating and the metal substrate, particularly under acidic conditions. The reactive diluent contains functional groups that can chemically interact with both the substrate surface and the polyolefin matrix, creating a bridging effect that enhances interfacial adhesion and protects against acid-induced delamination.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The composite coating system combines polyolefin's chemical resistance with the adhesion-promoting properties of the reactive diluent and crosslinking agent. This multi-functional composite structure provides both corrosion protection and strong substrate bonding, even in aggressive acidic environments where conventional single-material coatings would fail.

Inventive Principle:
Principle #40Composite materials

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 coating composition achieves enhanced mechanical and chemical resistance, as evidenced by high Konig hardness values and MEK double rub values, while maintaining a smooth appearance and ensuring adhesion even under acidic conditions, thus meeting the performance requirements for food and beverage containers.

Implementation Method 1

a maleic anhydride functionalized polyethylene (c) a polymeric stabilizing agent, and (d) a maleic anhydride modified polyethylene wax

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

a crosslinker, wherein the crosslinker is from 0 weight percent to 40 weight percent of the coating composition based on the total weight of the coating composition

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentEP2922925B1Coating compositions
Publication Date: 2019.12.04 DOW GLOBAL TECHNOLOGIES LLC
  • EP2922925B1 patent drawingFigure 1
  • EP2922925B1 patent drawingFigure 2
  • EP2922925B1 patent drawingFigure 3

AI summary

Embodiments of the present disclosure are directed towards coating compositions comprising from 20 to 85 percent of an aqueous dispersion based on a total weight of the coating composition, a basic water composition, and a crosslinker, wherein the aqueous dispersion comprises a melt blending product of (a) a base polymer comprising a polyolefin, (b) a polymeric performance improving agent (c) a polymeric stabilizing agent, and (d) a polymeric coupling agent.