Hot-melt adhesive for multipack container bonding

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Solution Overview

Problem

Current hot-melt adhesive formulations fail to provide sufficient cohesive strength, heat resistance, and adhesion to containers in various ambient conditions, leading to difficulties in separating individual containers in multipacks without damaging them and result in excessive packaging waste.

Innovation Solution

A hot-melt adhesive composition comprising 50-85 parts of metallocene catalysed polyolefin polymer, 10-25 parts of styrene block copolymer, 5-25 parts of paraffinic oil or polybutene as a reinforcing agent, and 0.05-1.5 parts of sterically hindered phenolic antioxidant or hindered amine light stabilizer, which allows for durable bonding and easy separation of containers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current commercial hot-melt adhesive formulations are used, then adhesive application is simple, but the adhesive lacks sufficient cohesive strength, heat resistance, and adhesion performance

Engineering Contradiction:
Improveadhesive performanceVSAvoidadhesive formulation complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a composite adhesive formulation combining multiple polymer types (polyolefin polymer, styrene block copolymer, polyisobutylene) with specific weight ratios. This composite approach allows the adhesive to simultaneously achieve high cohesive strength, heat resistance, and adhesion performance by leveraging the complementary properties of each component material.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges for each component including weight percentages of polymers (50-85%, 10-25%, 5-25%), molecular weight ranges, and processing temperatures. By controlling these parameters within defined ranges, the adhesive achieves optimal performance characteristics while maintaining manufacturability through standardized formulation specifications.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the adhesive provides very high cohesive strength and heat resistance for secure bonding, then container holding is reliable, but container separation becomes difficult

Engineering Contradiction:
Improvebond strengthVSAvoidcontainer separability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent formulates the adhesive with specific polymer combinations and plasticizer content (5-25% by weight) that create a dynamic bond strength characteristic. The adhesive maintains high strength during transport and storage conditions but allows controlled separation when consumers apply moderate force, achieving both reliable bonding and ease of separation through material dynamics.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent controls the balance between adhesive strength and separability by adjusting formulation parameters including the ratio of rigid to flexible polymer components, plasticizer content, and crosslinking degree. These parameter adjustments enable the adhesive to exhibit condition-dependent behavior: strong under normal conditions but separable under consumer handling conditions.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If shrink sleeve film or cardboard overwrap is used for multipack formation, then containers are held together securely, but packaging waste increases

Engineering Contradiction:
Improvemultipack stabilityVSAvoidpackaging material
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent eliminates the need for separate shrink sleeve films or cardboard overwraps by applying adhesive directly to the container surfaces. This extraction of the intermediate packaging layer reduces material usage and waste while maintaining secure multipack formation through direct adhesive bonding between containers.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the functions of container bonding and multipack formation into a single adhesive application process. The adhesive simultaneously provides the bonding mechanism and the protective packaging function, eliminating the need for separate packaging materials and reducing overall packaging waste.

Inventive Principle:
Principle #5Merging (Combining)

4Productivity

If the adhesive is applied in high speed automated processes, then productivity increases, but adhesive performance consistency becomes challenging

Engineering Contradiction:
Improveapplication speedVSAvoidadhesive performance consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent defines specific parameter ranges optimized for high-speed automated application including viscosity ranges, application temperature ranges, and cure time specifications. These controlled parameters ensure consistent adhesive performance even when applied at high speeds, allowing productivity increases without sacrificing bond reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent formulates the adhesive with pre-selected polymer and plasticizer combinations that provide optimal open time and cure characteristics for automated processes. This preliminary formulation design ensures the adhesive maintains consistent performance across high-speed production lines without requiring complex real-time adjustments during application.

Inventive Principle:
Principle #10Preliminary action

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 adhesive mixture provides high cohesive strength, heat resistance, and flexibility, enabling secure storage and transport while allowing easy separation of containers, reducing packaging waste and enabling automated application without secondary packaging.

Implementation Method 1

the adhesive must display a very high level of cohesive strength

Methodology Applied
Scientific EffectCohesion: Cohesion

Implementation Method 2

a basis polymer, wherein the basis polymer is consisting of a metallocene catalysed polyolefin polymer

Methodology Applied
Scientific EffectVan der Waals forces: Van der Waals Force

Implementation Method 3

the modifying polymer comprising a styrene block copolymer

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

a modifying polymer, the modifying polymer comprising a styrene block copolymer

Methodology Applied
Scientific EffectPhase separation: Phase Change

Implementation Method 5

the adhesive must have sufficient adhesion to the substrates to hold the containers together

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 6

a reinforcing agent comprising paraffinic oil, naphthenic oil, polybutene

Methodology Applied
Scientific EffectChain entanglement: Cohesion

Implementation Method 7

a stabilizer component comprising a sterically hindered phenolic antioxidant

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 8

a stabilizer component comprising a sterically hindered phenolic antioxidant

Methodology Applied
Scientific EffectFree radical scavenging: Redox Reactions

Implementation Method 9

a stabilizer component comprising a hindered amine light stabilizer

Methodology Applied
Scientific EffectPhoto-oxidation: Photo-oxidation

Implementation Method 10

a stabilizer component comprising a hindered amine light stabilizer

Methodology Applied
Scientific EffectUV absorption: Absorption (EM radiation)

Implementation Method 11

Hot-melt adhesives are applied to a substrate while in its molten state

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 12

and cooled to harden the adhesive layer

Methodology Applied
Scientific EffectFreezing: Freezing

Data Source

PatentEP3022269B1Hot-melt adhesive and use thereof
Publication Date: 2021.02.24 KHS GMBH

AI summary

Use of a hot-melt adhesive for adhesive bonding of at least a first packaging and a second packaging, the hot-melt adhesive comprising: (a) 50-85 parts per weight of a basis polymer, wherein the basis polymer is consisting of a metallocene catalysed poiyolefln polymer, preferably ethene-1-octene-copolymer; (b) 1 0-25 parts per weight of a modifying polymer, the modifying polymer comprising a styrene block copolymer; (c) 5-25 parts per weight of a reinforcing wax, preferably a polyethylene wax or a wax produced by the Fischer-Tropsch synthesis route, the wax component preferably comprising paraffinic oil, naphthenic oil, polybutene, dibasic ester, polyol or mixtures thereof; and (d) 0.05-1.5 parts per weight of a stabilizer component comprising a sterically hindered phenolic antioxidant and/or a hindered amine light stabilizer and a pack comprising the hot-melt adhesive.