Sulfonated Co-Polyester Cationic Dyeability
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Solution Overview
Problem
Current methods for producing cationic dyeable polyesters face challenges such as complex chemistry, acidic character issues, and difficulties in spinning fibers due to diethylene glycol formation and agglomeration, leading to poor dyeing properties and stain resistance.
Innovation Solution
A method involving polymerizing a first pre-polymer with a second pre-polymer to form a metal sulfonated co-polymer, reacting it with a fast crystallizing polyester block, and crystallizing the amorphous sulfonated co-polyester to produce a crystallized sulfonated co-polyester with improved dyeing affinity and stain resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Na-SIPA is directly added at the esterification stage to produce cationic dyeable polyester, then cationic dyeability is improved, but diethylene glycol formation increases and ether formation is acid-catalyzed leading to spinning difficulties
Solution Approach 1:
The patent applies preliminary action by pre-reacting Na-SIPA with dimethyl terephthalate to form a sulfonated complex before adding it to the esterification reaction. This pre-complex formation prevents direct acid-catalyzed etherification during esterification, thereby reducing diethylene glycol formation while maintaining cationic dyeability in the final polyester product.
2Ease of manufacture
If Na-SIPA is added to improve cationic dyeability, then dyeing properties are enhanced, but TiO2 agglomeration occurs leading to low melting point and spinning difficulties
Solution Approach 1:
The patent uses dimethyl terephthalate as an intermediary substance that mediates between Na-SIPA and the esterification system. The sulfonated complex formed between Na-SIPA and dimethyl terephthalate acts as a controlled intermediary that prevents direct acid-catalyzed side reactions, thereby preventing TiO2 agglomeration while preserving cationic dyeability.
3Object-generated harmful factors
If bis(hydroxyl ethyl) isophthalate-5-sulfonate is added at the end of esterification to minimize diethylene glycol formation, then DEG formation is reduced, but trimers, tetramers and oligomers form causing spinability issues
Solution Approach 1:
The patent applies preliminary action by forming the sulfonated complex with dimethyl terephthalate before the esterification reaction begins. This pre-formed complex incorporates the sulfonate group in a controlled manner during polymerization, preventing both diethylene glycol formation and oligomer formation that occur when sulfonated compounds are added at the end of esterification.
4Ease of manufacture
If normal polyester is used, then processing is simple, but ionic interaction sites are absent limiting dyeing to disperse dyes with poor color intensity and fastness
Solution Approach 1:
The patent creates a composite material system by forming a complex between Na-SIPA and dimethyl terephthalate that incorporates ionic sulfonate groups into the polyester structure. This composite approach maintains the simplicity of polyester processing while adding cationic dyeing capability through the integrated sulfonate groups, enabling versatile dyeing options.
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 resulting sulfonated co-polyester exhibits enhanced cationic dyeing affinity and improved low-temperature stain resistance, addressing the limitations of traditional polyester fibers.
Implementation Method 1
reacting the metal sulfonated co-polymer with a fast crystallizing polyester block to provide an amorphous sulfonated co-polyester
Implementation Method 2
crystallizing the amorphous sulfonated co-polyester to form a crystallized sulfonated co-polyester
Data Source
AI summary
A method of forming a polymer includes polymerizing a first pre-polymer, produced by the reaction of a dicarboxylic acid, or ester thereof with a first alkylene diol; with a second pre-polymer produced by the reaction of an aromatic sulfonate or a salt thereof, or ester thereof, with a second alkylene diol; to form a metal sulfonate copolymer; reacting the metal sulfonate co-polymer with a fast crystallizing polyester block having a degree of polymerization of at least about 20 to provide an amorphous sulfonated co-polyester; and crystallizing the amorphous sulfonated co-polyester to form a crystallized sulfonated co-polyester.