Blow-Molded Polyester Resin Composition for Wax Transfer Control

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Solution Overview

Problem

The transfer of wax-derived components to the surface of blow-molded articles, particularly toner bottles made from recycled PET, leads to deformation of toner particles, causing development defects and density unevenness in electrophotographic images.

Innovation Solution

A method involving the production of a preform through melt-kneading a resin mixture comprising a thermoplastic polyester, a carbodiimide compound, and a wax, followed by stretch-blow-molding to inhibit the transfer of wax-derived components to the surface by polymerizing or immobilizing them within the high-molecular-weight polyester.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional resin compositions (polyethylene terephthalate + 1,4-butane sultone) are used to prevent crystallization, then molten resin流动性 is improved, but bacterial contamination occurs and product reliability deteriorates

Engineering Contradiction:
Improvemolten resin流动性VSAvoidproduct reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent changes the chemical parameter of the resin composition by replacing 1,4-butane sultone with a carbodiimide compound having specific molecular weight and structural characteristics. This parameter change maintains molten resin流动性 while eliminating bacterial contamination, thus resolving the contradiction between flowability and reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a carbodiimide compound that provides temporary anti-crystallization effect during the critical cooling period, after which it decomposes or becomes inert. This short-lived functional additive prevents both crystallization and bacterial growth without requiring long-term preservative action, resolving the contradiction between flowability and reliability

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

2Stability of the object's composition

If 1,4-butane sultone is used as anti-crystallization agent, then crystallization during storage is prevented, but bacterial growth is promoted and product reliability deteriorates

Engineering Contradiction:
Improvecrystallization preventionVSAvoidproduct reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the chemical identity of the anti-crystallization agent from 1,4-butane sultone to a carbodiimide compound with specific molecular weight range (50-500). This parameter change maintains the anti-crystallization function while eliminating bacterial promotion, thus resolving the contradiction between composition stability and reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the previously harmful effect of 1,4-butane sultone (bacterial promotion) into a beneficial outcome by selecting a carbodiimide compound that not only prevents crystallization but also inhibits bacterial growth. The carbodiimide group reacts with water to form unstable intermediates that decompose without supporting bacterial growth, thus converting a harmful additive into a beneficial one

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If polyethylene terephthalate is used as base resin, then product strength is ensured, but crystallization occurs during storage reducing reliability

Engineering Contradiction:
Improveproduct strengthVSAvoidproduct reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent creates a composite resin composition by combining polyethylene terephthalate (for strength) with a carbodiimide compound (for anti-crystallization and antibacterial properties). This composite material maintains the strength of PET while adding functional properties that prevent crystallization and bacterial growth, thus resolving the contradiction between strength and reliability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the compositional parameters of polyethylene terephthalate by adding a specific amount of carbodiimide compound (0.1-5 wt%). This parameter change modifies the crystallization behavior of PET without significantly compromising its strength, thus resolving the contradiction between strength and reliability

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

Prevents the deformation of toner particles by restraining contact between wax-derived components and toner, thereby maintaining image quality in electrophotographic devices.

Implementation Method 1

it has been confirmed that when a specific amount of a carbodiimide compound is incorporated into a thermoplastic polyester, crystallization of the thermoplastic polyester can be prevented

Methodology Applied
Scientific EffectCrystallization inhibition:

Implementation Method 2

the carbodiimide compound reacts with water to form unstable compounds which subsequently decompose

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

bacterial contamination can be effectively prevented due to the antibacterial effect of the carbodiimide compound

Methodology Applied
Scientific EffectAntibacterial action:

Implementation Method 4

a step of producing a preform from a resin mixture comprising at least a wax, a thermoplastic polyester and a carbodiimide compound

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 5

a step of blow-molding the preform to produce a blow-molded article

Methodology Applied
Scientific EffectThermal processing: Heat Treatment

Data Source

PatentEP4427909B1Method of producing blow-molded product, resin composition, and pellets
Publication Date: 2026.05.06 CANON KK
  • EP4427909B1 patent drawingFigure 1
  • EP4427909B1 patent drawingFigure 2
  • EP4427909B1 patent drawingFigure 3~4

AI summary

A method for producing a blow-molded article (112), the method comprising: a step of producing a preform (104) from a resin mixture comprising at least a wax (202), a thermoplastic polyester and a carbodiimide compound; and a step of blow-molding the preform to produce a blow-molded article.