Toner Resin Composition for Low-Temperature Fixing and Anti-Blocking
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Solution Overview
Problem
Existing toner resins face challenges in achieving improved low-temperature fixing ability while maintaining anti-blocking properties at high temperatures and high humidity, and the incorporation of crystalline resins affects pulverisability.
Innovation Solution
A polyester resin with specific acid and hydroxyl values, containing 30 to 100 mol% aliphatic diols with 2 to 6 carbon atoms, reacted with aliphatic or aromatic carboxylic acids, providing a resin with excellent low-temperature fixing ability and good anti-blocking properties, along with a method for producing such resins for use in toner compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the molecular weight of the polyester resin is reduced to improve low-temperature fixing ability, then the low-temperature fixing ability is improved, but the anti-blocking property at high temperature and high humidity deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the polyester resin by incorporating specific amounts of crystalline resin components (adipic acid, sebacic acid, or dodecanedioic acid) and controlling the molar ratios of polyol to polycarboxylic acid components. This allows achieving both low-temperature fixing ability and anti-blocking property through compositional optimization rather than molecular weight reduction alone
Solution Approach 2:
The invention creates a composite polyester resin system by combining multiple resin components with different properties: the base polyester resin provides low-temperature fixing ability, while the incorporated crystalline resin components (adipic acid, sebacic acid, or dodecanedioic acid) provide anti-blocking property at high temperature and humidity. This composite approach resolves the contradiction between the two opposing requirements
2Temperature
If a crystalline resin is incorporated to improve low-temperature fixing ability, then the low-temperature fixing ability is improved, but the pulverisability deteriorates
Solution Approach 1:
The invention optimizes the molecular weight parameters of the polyester resin (controlling Mn and Mw within specific ranges) and the content of crystalline resin components to achieve a balance between low-temperature fixing ability and pulverisability. By controlling the degree of crystallinity and molecular weight distribution, the resin maintains both fixing performance and ease of pulverization in industrial manufacture
3Temperature
If the molecular weight is reduced to improve low-temperature fixing ability, then the low-temperature fixing ability is improved, but the resin strength deteriorates
Solution Approach 1:
The invention combines polyester resin with crystalline resin components (adipic acid, sebacic acid, or dodecanedioic acid) in specific proportions to create a composite material that maintains resin strength while achieving low-temperature fixing ability. The crystalline components provide structural reinforcement that compensates for the reduced molecular weight
Solution Approach 2:
The invention adjusts the molecular weight parameters (Mn: 2,000-10,000, Mw: 5,000-50,000) and the content of crystalline resin components (0.1-10 mmol/g) to optimize the balance between low-temperature fixing ability and resin strength, preventing the resin from becoming too weak when molecular weight is reduced
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 solution results in toners with enhanced low-temperature fixing ability and improved anti-blocking properties, facilitating economic industrial production by ensuring excellent pulverisability and resin strength.
Implementation Method 1
a polyester resin obtained by polymerizing by condensation polymerization: (a) a diol component comprising a mixture of specific diols, and (b) a mixture of acid components comprising an aliphatic unsaturated dicarboxylic acid
Data Source
AI summary
A toner and a resin for toner are provided which are of good low-temperature fixing ability and good anti-blocking property of toner at high temperature and high humidity and good pulverisability. The present invention is directed to a resin for toner, the resin comprising a polyester resin (A) produced by reacting a polyester resin (a) having an acid value of 6 mgKOH/g or less and a hydroxyl value of 10 to 80 mgKOH/g with at least one carboxylic acid (b) selected from the group consisting of aliphatic carboxylic acids, aromatic carboxylic acids, their anhydrides and lower alkyl (C1-C4) esters, wherein the equivalent ratio OHa/COOHb is 0. 55 to 1. 0 where OHa represents the equivalent of the hydroxyl groups originating in (a) in the reaction of (a) and (b) and COOHb represents the equivalent of the carboxyl groups originating in (b) in the reaction of (a) and (b), and wherein the polyester resin (A) has an acid value of 13 to 50 mgKOH/g and a hydroxyl value of 8 mgKOH/g or less; and a toner composition including the same.