Hot Melt Adhesive Composition for Absorbent Articles

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Solution Overview

Problem

Existing hot melt adhesive compositions for absorbent and textile articles face challenges with high costs, poor processability, and equipment damage due to cured adhesive residuals, which are difficult to manage and require frequent maintenance.

Innovation Solution

An adhesive composition comprising 70-90 wt.% amorphous copolymers and 10-30 wt.% heterophase copolymers, with specific monomer units and catalyst systems, that is free of polyisobutylene and tackifiers, offering improved bonding properties and reduced viscosity for easier processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If olefin-based hot melt adhesives are formulated with high bonding properties, then bonding reliability is improved, but processability deteriorates due to difficulty in handling and applying the adhesive

Engineering Contradiction:
Improvebonding reliabilityVSAvoidprocessability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent modifies the chemical composition parameters of the adhesive by incorporating specific polymer blends (polyethylene, polypropylene, elastomers) and controlling the ratio of bonding agents to modifiers. This allows tuning of the adhesive's viscosity and bonding characteristics to achieve both reliable bonding and ease of processing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adhesive comprises a composite formulation combining multiple polymer types (polyethylene, polypropylene, elastomeric polymers) with specific additives. This composite structure enables the material to exhibit both strong bonding properties and improved processability that neither component could achieve alone.

Inventive Principle:
Principle #40Composite materials

2Reliability

If hot melt adhesives are applied in manufacturing processes, then bonding is achieved, but equipment damage occurs due to cured adhesive residuals accumulating on equipment parts

Engineering Contradiction:
Improvebonding performanceVSAvoidequipment damage from residuals
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The adhesive formulation is designed to be easily removable or replaceable, allowing equipment to be quickly cleaned or reconfigured. The specific polymer blend enables the adhesive to be applied effectively while minimizing long-term accumulation and damage to equipment surfaces.

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

Solution Approach 2:

By adjusting the chemical composition parameters including the use of specific elastomers and plasticizers, the adhesive's curing characteristics and residue properties are modified to reduce adhesion to equipment surfaces while maintaining bonding performance.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If traditional hot melt adhesive formulations are used with tackifiers comprising up to 65% of the composition, then bonding performance is achieved, but cost increases and sourcing becomes difficult

Engineering Contradiction:
Improvebonding performanceVSAvoidcost and availability
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent reduces or eliminates the use of expensive tackifiers by extracting this specific component from the traditional formulation. Instead, bonding performance is achieved through alternative mechanisms using the polymer blend composition and physical properties of the hot melt adhesive itself.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The formulation parameters are fundamentally changed by shifting from a tackifier-dominated composition to a balanced polymer blend system. This reconfiguration maintains bonding effectiveness while using more readily available and cost-effective raw materials.

Inventive Principle:
Principle #35Parameter changes

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 composition provides enhanced bonding performance, reduced equipment maintenance, and lower costs by minimizing tackifier use, while maintaining suitable viscosity for efficient application and equipment compatibility.

Implementation Method 1

adhesive compositions such as hot melt adhesive compositions are a type of adhesive that is applied in molten form onto parts to be adhesively bonded, before setting and solidifying upon cooling

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

the first heterophase copolymer has a higher Enthalpy of Fusion than the second heterophase copolymer, as measured by the Enthalpy of Fusion Test Method

Methodology Applied
Scientific EffectEnthalpy of fusion: Latent Heat

Data Source

PatentEP3781639B1Adhesive composition for absorbent articles
Publication Date: 2024.09.25 PROCTER & GAMBLE CO

AI summary

Described herein is an adhesive composition including (a) from about 70 wt. % to about 90 wt. % of one or more copolymers, and (b) from about 10 wt. % to about 30 wt. % of one or more heterophase copolymers. The one or more copolymers include (i) from about 30 mole % to about 70 mole % of monomer units selected from the group consisting of ethylene, 1 -butene, and mixtures thereof; and (ii) from about 30 mole % to about 70 mole % of propene monomer units. The adhesive composition is free of polyisobutylene. The adhesive composition has a viscosity of from about 2,000 mPa-s to about 11,500 mPa-s at 150 °C. The one or more heterophase copolymers includes a first heterophase copolymer and a second heterophase copolymer.