CAS 24434-90-0 | 2,3,5-tricarboxyl cyclopentane acetic acid: flexible display and 5G high frequency era, a new choice for domestic substitution of alicyclic polyimide monomers

In-depth analysis of the key role of 2,3, 5-tricarboxycyclopentane acetic acid (CAS 24434-90-0) in the alicyclic polyimide industry chain, covering core application scenarios such as OLED orientation film, flexible substrate and semiconductor packaging, and providing procurement selection guidelines.

The “Invisible Card” of Flexible Electronic Industry Chain”

when the folding screen mobile phone becomes the flagship standard, when the OLED panel to larger size, higher refresh rate evolution, polyimide (PI) film as the underlying support material, its performance ceiling directly determines the end product experience ceiling. In the entire PI material supply chain, there is a node that is rarely mentioned by terminal brands but highly affects the quality of film formation-alicyclic tetracarboxylic acid monomer.

Among them, 2,3, 5-tricarboxycyclopentane acetic acid (CAS 24434-90-0) is the core precursor for the preparation of alicyclic dianhydrides (such as TCA series). It is not as well known in the industry as PMDA and BPDA, but it can hardly be replaced in scenes that require “colorless transparency + low dielectric + bendable.

Molecule Archives: What is it?

unlike common aromatic tetraacids (such as pyromellitic acid), its backbone is a saturated alicyclic structure. This means that there is no extended conjugated π-bond system in the molecule, fundamentally cutting off the electron delocalized path-this structural difference is the source of its outstanding optical and electrical properties.

why did alicyclic monomers become “just needed”?

Traditional aromatic polyimides (such as Kapton type) have excellent heat resistance, but there are three difficult to avoid the short board:

first, the color issue. The conjugated structure of the aromatic ring leads to strong absorption in the visible region, and the film is yellowish brown. This is a fatal defect for OLED cover plates and transparent conductive film substrates that require high light transmittance.

Second, the dielectric is high. 5G millimeter wave and high-speed signal transmission require that the dielectric constant (Dk) and loss factor (Df) of the substrate be as low as possible. The polarizability of the aromatic ring is high, which limits the space for further dielectric reduction.

Third, solubility is limited. Most aromatic PI is insoluble in conventional organic solvents and can only be supplied in the form of thin films, making it difficult to achieve refinement processes such as solution coating and inkjet printing.

After the introduction of 2,3, 5-tricarboxycyclopentane acetic acid as an alicyclic precursor, the regularity and rigidity of the polymer main chain decreased, and the conjugation was broken. Direct benefits include:

the light transmittance of the film is significantly improved, and the yellowness index (YI) is greatly reduced.

The dielectric constant can be reduced to 2.8 or even lower to meet the needs of high-frequency communication.

Better dissolution processability in polar solvents such as NMP and DMAc

which high-boom tracks is it being consumed on?

1. OLED and LCD liquid crystal alignment film

in the panel process, the alignment film needs to be chemically stable at high temperatures (typically> 200°C), while not being colored. Alicyclic PI oriented film has become the first choice for high-end production line because of its low birefringence and excellent thermal dimensional stability.

2. Flexible display cover plate and folding screen substrate

the folding screen requires more than 200000 times of bending life. The alicyclic structure gives the molecular chain a higher degree of internal rotational freedom, which makes the film less prone to microcracks during repeated bending. Compared with the fully aromatic system, it has a better balance between toughness and rigidity.

3. Advanced package with RDL dielectric layer

in fan-out wafer level packaging (FOWLP) and 2.5D/3D integration, low-stress, low-dielectric PI coatings are used for stress buffering and redistribution layer (RDL) insulation. The low hygroscopicity and low ion content of the alicyclic PI helps to suppress warpage and electrochemical migration after encapsulation.

4. 5G antenna and high frequency substrate

the millimeter wave band is extremely sensitive to dielectric loss. The Dk/Df value of PI substrate constructed by alicyclic monomer is obviously better than that of traditional aromatic system, and it is gradually entering the supply chain of flexible board of base station antenna module and vehicle radar.

5. Research and frontier materials

its four carboxyl groups give it multi-dentate coordination ability, in the metal organic framework (MOFs), coordination catalysts and special chelating agent synthesis, is also a hot laboratory-level ligand choice.

Procurement Pit Avoidance Guide: What Indicators Should I Focus on when Selecting?

For formulation engineers and procurement managers, not all products labeled “24434-90-0″ can be directly used in electronic grade applications. The following five dimensions are recommended for supplier evaluation:

① Chemical purity and isomer control Electronic grade application recommended purity ≥ 99.0, and it is best to specify the proportion of major isomers. Products with mixed rotation or uncontrolled isomers may cause the melting point of the downstream dianhydride to drift and increase the risk of gelation during polymerization.

Metal ion content Sodium, potassium, iron, copper and other alkali metals and transition metal ions are invisible killers of panel and package yield. Electronic standards usually require less than 1-2 ppm for each individual item and less than 5 ppm for total metal ions.

③ Moisture and residual solvent The compound has certain hygroscopicity. If the package sealing or improper storage, acid value will drop, the actual yield of dehydration to anhydride will be compromised. It is recommended to detect Karl Fischer moisture after arrival.

④ Batch consistency from 1kg small test to 100kg amplification, the melting point range of the product, HPLC purity map, color value should be consistent. Require suppliers to provide a COA for each batch and establish an annual quality agreement.

⑤ Supply chain resilience Limited global suppliers of such specialty monomers. It is recommended to give priority to suppliers with their own synthetic routes rather than simple trade sub-packaging to avoid the risk of supply outages and quality fluctuations.

FAQ

q: Can this acid be directly used to synthesize polyimide? A: Generally, it is not directly used for polymerization in industry. The standard route is to first dehydrate the dianhydride and then react with the diamine. Directly with tetracarboxylic acid and diamine polymerization, reaction activity control and molecular weight are difficult to achieve electronic grade requirements.

Q: Is it a substitution relationship with the products of PMDA and BPDA routes? A: It is not a simple substitution, but a complement. Aromatic PI still has advantages in extreme thermal environments> 300 ℃, while alicyclic PI is better in optically transparent, low dielectric, solution processable scenarios. In practical application, there is even copolymerization modification to take into account the advantages of both sides.

Q: Can stable mass production be achieved in China at present? A: Yes. There are a few domestic manufacturers with independent synthesis capabilities to break through 100 tons of production capacity, product purity and imported samples, and in the delivery cycle and customized services more flexible.

Q: What are the special precautions during storage? A: It is recommended to store in a cool and dry environment (2-8 ℃ is the best) and avoid mixing with strong alkali and strong oxidant. If it is not used up once after opening, it should be filled with nitrogen or stored in a dryer to prevent moisture absorption and agglomeration.

Conclusion

in the process of transition of polyimide materials from “high temperature resistant engineering plastics” to “precision electronic functional materials”, the alicyclic monomer route represented by 2,3,5-tricarboxycyclopentane acetic acid (CAS 24434-90-0) is playing an increasingly critical role as the underlying support.

For domestic enterprises that are laying out OLED oriented films, flexible display substrates or advanced packaging materials, locking a high-purity, high-consistency monomer supply source is not only the need for cost control, but also a strategic choice for supply chain security.

If you need to obtain the detailed COA, TDS and SDS documents of the product, or apply for a small batch of samples for formula verification, please contact our technical team through the station letter or official website.