Contact Nozzle Air Spreading for Elastic Strand Adhesive Coating

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional adhesive dispensing systems for elastic strands in hygiene products face challenges in achieving optimal coating characteristics, including high creep resistance and force retraction, due to issues with adhesive control and distribution, particularly with non-contact systems where air patterns can be disrupted and filament control is difficult, and contact systems where thick coatings can impede retraction.

Innovation Solution

A contact nozzle design that includes a slot for receiving the elastic strand, an adhesive passage for delivering adhesive to the strand's upper surface, and a pressurized air passage to spread the adhesive around the strand's periphery, combined with an expansion chamber for die swell and a strand guide to position the strand, ensuring consistent and controlled adhesive application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If non-contact dispensing systems use air jets to spiral the adhesive filament, then the adhesive can be applied to the elastic strand, but the air pattern is disrupted when orifices are blocked, leading to uncontrolled adhesive filament pattern

Engineering Contradiction:

Improveadhesive filament controlVSAvoidair jet positioning precision

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the non-contact air jet system with a contact dispensing system where the nozzle physically contacts the elastic strand. This substitution eliminates the complexity of precise air jet positioning and the reliability issues of blocked orifices, while maintaining effective adhesive application through direct contact and pressurized air spreading.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces pressurized air as an intermediary between the adhesive application and the elastic strand. The air is discharged through orifices in the nozzle to spread the adhesive around the strand periphery, providing controlled distribution without requiring complex mechanical positioning systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If contact dispensing systems apply thick adhesive coatings to ensure coverage, then creep resistance is improved, but force retraction is impeded

Engineering Contradiction:

Improvecreep resistanceVSAvoidforce retraction impairment

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies adhesive with varying thickness at different locations on the elastic strand. The pressurized air spreads the adhesive to create thinner coatings at the periphery while maintaining adequate coverage, ensuring both creep resistance through sufficient adhesive presence and force retraction by avoiding overly thick coatings that would impede elastic recovery.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies adhesive in a controlled manner where the initial deposition may be sufficient or slightly excessive, but the subsequent pressurized air spreading distributes and thins the adhesive to achieve the optimal balance between creep resistance and force retraction, preventing the harmful effect of overly thick coatings.

Inventive Principle:

Principle #16Partial or excessive action

3Stability of the object's composition

If non-contact dispensing systems use high viscosity adhesive to maintain filament control, then filament stability is improved, but adequate control in flight requires relatively high viscosity

Engineering Contradiction:

Improveadhesive filament stabilityVSAvoidadhesive viscosity requirement

Core Design Contradiction:

Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent replaces the non-contact filament delivery system with a contact nozzle system that delivers adhesive directly to the elastic strand. This substitution eliminates the need for high viscosity to maintain filament stability during flight, as the adhesive is applied through direct contact and then spread by pressurized air, allowing use of lower viscosity adhesives.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 contact nozzle system provides a consistent adhesive coating along the entire periphery of the elastic strand, maintaining elasticity and achieving desirable levels of creep resistance and force retraction by varying adhesive thickness, while preventing adhesive buildup and ensuring reliable bonding with nonwoven substrates.

Implementation Method 1

The expansion chamber is sized to enable die swell of the adhesive exiting the adhesive orifice

Methodology Applied

Scientific EffectDie swell:

Implementation Method 2

discharge pressurized air towards the adhesive on the strand... discharge air at the adhesive in contact with the strand, thereby causing the adhesive to spread around the periphery

Methodology Applied

Scientific EffectPressurized air flow:

Data Source

PatentEP2696991B1System, nozzle, and method for coating elastic strands

Publication Date: 2016.09.14 NORDSON CORP

Figure 1
Figure 2A
Figure 2B~2C

AI summary

A contact nozzle (2) for coating an elastic strand (12) with an adhesive (14). Air (1 8) is discharged at the adhesive (14) in contact with the strand (12), causing the adhesive (14) to spread around the periphery of the strand (12). The air (18) assists with release of the adhesive (14) from the nozzle (2) and also cleans the nozzle (2) to discourage adhesive build-up on the nozzle (2).