Coated Single-Layer BOPP Film for Thin Recyclable Laminates

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Solution Overview

Problem

Existing packaging laminates face challenges in reducing polymer content while maintaining desired properties such as optical quality, barrier properties, and recyclability, often requiring multiple layers that complicate recycling and are uneconomical.

Innovation Solution

A single-layer biaxially oriented polypropylene film with a coating of maleic anhydride-functionalized polypropylene and a dispersion coating, such as polyurethane, which includes nanoparticles, to enhance adhesion, barrier properties, and metallizability, allowing for thin film production without antiblocking agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the thickness of the polymer film is reduced, then the polymer content and raw material requirements are reduced, but the overall thickness of the packaging laminate must be increased to maintain structural integrity and meet foreign material limits

Engineering Contradiction:
Improvepolymer contentVSAvoidoverall thickness of packaging laminate
Core Design Contradiction:
Quantity of substanceVSLength of stationary object

Solution Approach 1:

The patent combines multiple functional properties into a single polymer layer by using a multicomponent composition that integrates sealing, antiblocking, optical, and adhesion functions, eliminating the need for separate layers and enabling thin-film design while maintaining overall laminate performance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a composite polymer composition containing multiple components (polymer A, polymer B, polymer C, and optional additives) within a single layer, allowing optimization of multiple properties simultaneously and enabling reduced thickness while maintaining structural and functional requirements

Inventive Principle:
Principle #40Composite materials

2Reliability

If multilayer extruded polymer films are used to achieve desired properties, then optical, mechanical, and adhesion properties can be optimized, but the complexity of the film structure increases and recycling becomes difficult

Engineering Contradiction:
Improveoptical and mechanical propertiesVSAvoidfilm structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functional layers into a single multicomponent extruded layer, combining sealing, antiblocking, optical, and adhesion functions in one homogeneous structure that maintains the performance benefits of multilayer films while eliminating their complexity and recycling issues

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single-layer composition is designed to perform multiple functions simultaneously: sealing at different temperatures, providing antiblocking effect, ensuring optical quality, and offering adhesion to various substrates, making the film structure universal and eliminating the need for specialized layers

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If AB masterbatch with solid particles is added to achieve antiblocking effect, then winding and unwinding of the film is improved, but the appearance and metallizability of the film are impaired

Engineering Contradiction:
Improvewinding and unwindingVSAvoidappearance and metallizability
Core Design Contradiction:
Ease of operationVSIllumination intensity

Solution Approach 1:

The patent changes the fundamental parameter of antiblocking mechanism from solid particle addition to controlled crystallization-induced lasso formation, achieving antiblocking effect through molecular structure changes that do not affect optical properties or metallizability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical antiblocking approach (solid particles) with a molecular-level approach (crystallite transformation creating lasso structures), substituting a physical mechanism that interferes with light and metal deposition with one that operates at the molecular level

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If very pure and expensive BOPP-C raw materials are used with slow cooling to achieve crystallite transformation, then thin films with good properties can be produced, but production speed becomes slow and uneconomical

Engineering Contradiction:
Improvefilm quality and thicknessVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the crystallization parameters by using specific polymer compositions with controlled molecular weights and compositions that enable rapid crystallization at production-relevant cooling rates, eliminating the need for slow cooling while maintaining film quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces localized nucleation sites and controlled crystallization zones within the polymer composition that enable rapid and uniform crystallite transformation throughout the film thickness, achieving high-quality thin films at high production speeds

Inventive Principle:
Principle #3Local quality

5Manufacturing precision

If BOPP-C raw materials with little phosphite are used for technical applications, then crystallite transformation is achieved, but the materials are weakly stabilized and difficult to recycle

Engineering Contradiction:
Improvecrystallite transformationVSAvoidstabilization and recyclability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent creates a composite polymer composition that combines polymers with different phosphite contents and molecular characteristics, achieving both effective crystallite transformation and good stabilization/recyclability by balancing the properties of individual components

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 solution enables thin, high-quality films with improved recyclability, reduced polymer content, and enhanced production speed, while maintaining optical and metallization properties, thus overcoming the limitations of multilayer films.

Implementation Method 1

The extruded polypropylene layer consists of homo-polypropylene and maleic anhydride-functionalized polypropylene

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

at least one coating, in particular a dispersion coating, comprising polyurethane

Methodology Applied
Scientific EffectCoating: Coatings

Data Source

PatentEP4667514A1Coated single ply extruded bopp film
Publication Date: 2025.12.24 BRUCKNER MASCHINEHAU GMBH & CO KG
  • EP4667514A1 patent drawingFigure 1~2
  • EP4667514A1 patent drawingFigure 3
  • EP4667514A1 patent drawing

AI summary

The present invention relates to a coated, biaxially oriented polypropylene film 110, a laminate material 100 comprising this polypropylene film 110, and a method for producing the polypropylene film 110. The polypropylene film 110 is a single-layer extruded polypropylene film (BOPP film) comprising an extruded polypropylene layer 112 and at least one coating 114. The extruded polypropylene layer 112 comprises a homo-polypropylene and a maleic anhydride-functionalized polypropylene. The coating 114 is a dispersion coating comprising polyurethane.