Toothbrush Bristle Bonding for Thin-Walled Carriers

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Solution Overview

Problem

Existing methods for manufacturing brushes, particularly toothbrushes, struggle with reliably attaching bristle filaments to thin-walled bristle carriers, as anchor technologies fail and material-bonding methods lack dimensional accuracy.

Innovation Solution

A method involving heating only the attachment-side ends of bristle filaments to melt them, bonding them metallurgically to a bristle carrier without melting the carrier, using compatible materials and adhesion promoters like primers or additives to ensure a strong connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If anchor technology is used to attach bristle bundles to the brush head, then the attachment strength is improved, but the minimum material thickness requirement increases

Engineering Contradiction:
Improveattachment strengthVSAvoidmaterial thickness
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The patent extracts the anchoring function from the brush head material and relocates it to the bristle bundle itself by melting the bristle ends to create self-anchoring anchors. This eliminates the need for thick brush head material to accommodate separate anchors, as the anchoring mechanism is now integrated into the bristle structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces heat as an intermediary to melt the bristle filament ends, creating a molten state that allows the bristles to be pressed into the brush head and form self-anchoring structures. This thermal intermediary enables the attachment process without requiring thick material, as the melting and pressing action creates mechanical interlocking directly at the bristle-brush head interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If material bonding method is used to join bristle filaments to bristle carrier, then the attachment reliability is improved, but the dimensional accuracy deteriorates

Engineering Contradiction:
Improveattachment reliabilityVSAvoiddimensional accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by heating only the attachment-side ends of the bristle filaments to melting point while keeping the bristle carrier and other bristle portions at lower temperatures. This localized heating ensures that only the specific attachment zones undergo material bonding, preserving the dimensional accuracy of the overall brush structure while achieving reliable attachment at the critical interfaces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses partial action by melting only the necessary portion of the bristle filaments (the attachment ends) rather than melting the entire bristle carrier or all bristle components. This selective melting provides sufficient material bonding for reliable attachment while minimizing thermal distortion and preserving dimensional accuracy of the non-heated portions.

Inventive Principle:
Principle #16Partial or excessive action

3Strength

If bristle carrier is melted for bonding, then the bonding strength is improved, but the dimensional stability deteriorates

Engineering Contradiction:
Improvebonding strengthVSAvoiddimensional stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by restricting melting to only the attachment-side ends of the bristle filaments while maintaining the bristle carrier and other bristle portions in a solid, dimensionally stable state. This localized melting creates strong bonds at the attachment interfaces without subjecting the entire brush head structure to thermal processing that would cause dimensional changes.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses partial action by melting only the minimal necessary portion of the bristle material (the attachment ends) rather than melting the entire bristle carrier. This selective approach provides sufficient bonding strength for reliable attachment while preserving the dimensional stability of the bulk bristle carrier structure that remains below melting temperature.

Inventive Principle:
Principle #16Partial or excessive 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

This approach allows for reliable and dimensionally stable attachment of bristle filaments to thin-walled carriers, enhancing the quality and enabling environmentally friendly production with biodegradable materials.

Implementation Method 1

the attachment-side ends of bristle filaments of a bristle arrangement (3) to be attached are heated with a heating device (19) and are melted in contrast to the bristle carrier (2)

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

the bristle carrier (2) and the attachment-side ends (6) of bristle filaments (4) of a bristle arrangement (3) to be attached are heated with a heating device (19)

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4032432B1Method of manufacturing brushes and brush manufacturing device
Publication Date: 2026.01.21 ZAHORANSKY AG
  • EP4032432B1 patent drawingFigure 1~3
  • EP4032432B1 patent drawingFigure 4~5
  • EP4032432B1 patent drawingFigure 6~8

AI summary

The invention relates, inter alia, to a method for manufacturing a brush (1), in particular a toothbrush, with a bristle carrier (2) and a bristle arrangement (3) made of bristle filaments (4), wherein the bristle carrier (2) and attachment-side ends (6) of the bristle filaments (4) of the bristle arrangement (3) are heated and the attachment-side ends (6) of the bristle filaments (4) are melted in contrast to the bristle carrier (2), after which the bristle carrier (2) and the bristle filaments (4) of the bristle arrangement (3) are joined together.