The application of isophthalic acid is very wide. It can be used to produce coatings, polyester resins, unsaturated polyester resins, special fibers, hot melt adhesives, printing inks, polyester fiber dyeing modifiers, and resin plasticizers. More information about the application of isophthalic acid is as followed.

Introduction of Isophthalic Acid (IPA)?

Isophthalic acid (IPA) is also known as 1,3-phthalic acid and isophthalic acid. It is white crystalline powder or acicular crystal. Its melting point is from 345 degrees to 347 degrees and it can be sublimated. IPA can be easily soluble in methanol, ethanol, acetone, and Glacial acetic acid. It is slightly soluble in boiling water, but insoluble in benzene, toluene, and petroleum ether. Isophthalic acid has strong heat resistance, hydrolysis resistance, and chemical resistance. It is flammable and low in toxicity.

Application of IPA

Copolyester Polymer

One copolyester polymer can be formed by isophthalic acid, terephthalic acid, and ethylene glycol with a mole fraction of 0.01-0.1. That polymer has good tear resistance, impact resistance, melt viscosity, and dyeability. As a result, it can be used for various fibers and film products, like high resilience and heat-bonded polyester fiber, hydrothermal shrinkage blended fiber, soft bulky imitation silk, artificial silk, imitating natural fiber, insulating hollow acid, and alkali resistant polyester fiber, antistatic fiber, etc.

Low Melt Polyester

Generally, the melting point of PET polyester produced is about 250℃. While the melting point is about 65℃ for polyester made from 100% isophthalic acid. If we use 50% isophthalic acid to replace Phthalic acid during the production process, the resulting copolymer will have a melting point of about 120°C. For this reason, the content of isophthalic acid can be changed in a wide range according to the requirements of polymer performance. That’s how we customize the low melt polyester chips based on different demands. The filaments made from such PET chips can be used to make flexible fabrics, which are light, soft, and luxurious. In addition to the thermally-bonded non-woven fabrics, low melt fibers can also be used as fillers to increase the bulkiness of the non-woven fabrics, reduce the weight of the fillers, and increase the thermal insulation performance. In the manufacture of ultra-fine fibers, the dyeing performance is better than pure PET ultra-fine fibers due to the shrinkage of the crystalline area.
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Unsaturated Polyester

The isophthalic acid type unsaturated resin is the polycondensation of isophthalic acid, butanediol anhydride, and ethylene glycol. It has better hydrolytic stability, higher hardness, and higher hardness than the phthalic acid type unsaturated resin. Isophthalic acid mixed with high-performance paper materials can be made into flame-retardant resins and structural resins with good physical properties and low cost, which are used in the manufacture of elevators, handrails, and fishing rods.
Our water-soluble polyester chip belongs to the unsaturated polyester polymer. It is made from isophthalic acid’s modified monomer, 5-SSIPA.

Modified Monomer for Cationic Dyeable Resin

Isophthalic acid can produce dimethyl isophthalate-5-sodium sulfonate (SIPM), which is a modified monomer for polyester chips. SIPM can make the modified polyester fiber dyed more bright and dense. The introduction of SIPM into polyester chips can produce cationic modified polyester filaments. Although its appearance is not much different from ordinary polyester filaments, the use of cationic modification not only greatly improves the color absorption performance of the fiber, but also reduces the degree of crystallinity. As a result, the dyeing molecules are easy to penetrate, which makes the fiber easy to color. This kind of fiber not only ensures cationic dyeability, but also increases the micropores of the fiber, improves the dye uptake, air permeability, and moisture absorption of the fiber, thereby further adapting to the artificial utilization of polyester fiber. Silky simulation can make the fabric soft, breathable, comfortable, antistatic, co-dyed with wool at room temperature and pressure.
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