To determine the quality of the epoxy accelerator DMP-30 (2,4,6-tris(dimethylaminomethyl)phenol), a comprehensive evaluation can be conducted from aspects such as **appearance and physical property testing**, **chemical index analysis**, **application performance testing**, and **impurity and safety assessment**. The specific methods are as follows: ### **I. Appearance and Physical Property Testing** 1. **Appearance and State** - * *Normal Standard**: Colorless to light yellow transparent liquid, free of suspended matter or precipitation. - **Abnormality Judgment**: Dark color (such as tan), turbidity, or layering may indicate raw material oxidation, impurity residue, or deterioration due to improper storage. 2. **Odor** - **Normal Standard**: Characteristic amine odor (similar to ammonia or weak alkaline smell), without pungent stench or peculiar smell. - **Abnormality Judgment**: Strong rancid or putrid odor may indicate product decomposition or contamination. 3. **Density and Viscosity** - **Testing Method**: Measure using a densitometer or viscometer (such as a rotational viscometer), with reference to standard values (typically density: approximately 0.97–0.99 g/mL; viscosity: approximately 20–50 mPa·s/25°C). - **Quality Correlation**: Deviations from the standard range in density or viscosity may indicate unstable production processes or adulteration with other solvents. ### **II. Chemical Index Analysis** 1. **Amine Value (Key Index)** - **Testing Principle**: Determine the amino content through acid-base titration to reflect the active ingredient concentration. - **Standard Range**: Theoretical amine value is approximately **500–530 mgKOH/g** (purity ≥ 99%). - **Quality Judgment**: - Amine value close to the theoretical value: High purity and strong promoting effect. - Low amine value: May contain water, low-molecular impurities, or incomplete synthesis. 2. **Moisture Content** - **Testing Method**: Karl Fischer method (volumetric or coulometric method). - **Standard Requirement**: High-quality products have a moisture content ≤ 0.5% (some high-end products require ≤ 0.3%). - **Risk Warning**: Excessive moisture can cause emulsification in the epoxy resin system, affect curing effects, and even corrode metal substrates. 3. **pH Value** - **Testing Method**: Measure the pH of a 10% aqueous solution using a pH test strip or pH meter. - **Normal Range**: Alkaline, with a pH of approximately 10–12. - **Abnormality Judgment**: A pH lower than 9 (e.g., <9) may indicate the presence of acidic impurities or decomposition products, affecting the accelerator's activity. 4. **Purity and Impurities** - **Testing Method**: Analyze using gas chromatography (GC) or high-performance liquid chromatography (HPLC). - **Key Indicators**: - Main component (DMP-30) content ≥ 99%. - Impurities (such as free amines and phenolic by-products) ≤ 1%. - **Risk Points**: Impurities may cause abnormal curing speed, product discoloration, or degradation of mechanical properties. ### **III. Application Performance Testing** 1. **Curing Promotion Effect** - **Testing Method**: - Mix at a fixed ratio (e.g., 100 parts epoxy resin, 0.5–2 parts DMP-30) and observe the gel time (25°C). - High-quality products should control the gel time within **30–60 minutes** (specific time varies by epoxy resin type). - **Judgment Basis**: - Too short gel time: May contain excessive catalyst, leading to insufficient working time. - Too long gel time: Low accelerator activity, possibly due to insufficient purity or failure. 2. **Properties of Cured Products** - **Testing Items**: - **Mechanical Properties**: Tensile strength, flexural strength (refer to standards such as GB/T 2568 and GB/T 2567). - **Thermal Properties**: Glass transition temperature (Tg, DSC method), heat resistance (e.g., water resistance, aging resistance). - **Quality Correlation**: - High-quality accelerators should enable cured products to meet industry standards (e.g., tensile strength ≥ 30 MPa, Tg ≥ 60°C). - Significantly lower-than-expected performance may indicate poor compatibility between the accelerator and resin or cross-linking structure interference from impurities. 3. **Color Stability** - **Testing Method**: Age the cured epoxy resin sample under ultraviolet light or high temperature and observe color changes. - **Quality Requirement**: High-quality products should prevent yellowing or blackening of cured products, especially for light-colored or transparent products. ### **IV. Impurity and Safety Assessment** 1. **Heavy Metals and Harmful Substances** - **Testing Items**: Lead (Pb), mercury (Hg), cadmium (Cd), etc. (refer to RoHS and REACH regulations). - **Application Scenarios**: For applications in food contact, medical, and other fields, strict control of harmful impurities is required (e.g., Pb ≤ 10 ppm). 2. **Storage Stability** - **Testing Method**: Store the sample at 50°C for 7 days and observe changes in appearance and amine value. - **Quality Requirement**: Qualified products should show no obvious discoloration or layering, with an amine value decrease ≤ 5%. ### **V. Reference Standards and Supplier Qualifications** 1. **Implementation Standards**: - Domestic reference: General requirements for amine-based curing agents in HG/T 4883-2016 *Amine Curing Agents for Epoxy Resins*. - International reference: ASTM D2073 *Standard Test Methods for Amine Curing Agents*. 2. **Supplier Qualifications**: - Request a COA (certificate of analysis) and MSDS (material safety data sheet) , focusing on amine value, moisture, and purity data. - Prioritize manufacturers certified under the ISO 9001 quality management system to reduce batch stability risks. ### **Summary: Quick Judgment Steps** 1. **Preliminary Screening**: Observe appearance and odor, measure density/viscosity, and eliminate obviously abnormal products. 2. **Core Testing**: Commission third-party testing agencies to determine amine value, moisture, and purity (GC/HPLC). 3. **Application Verification**: Test curing speed and product performance through small samples to ensure they meet actual requirements. For extremely high-quality requirements (e.g., aerospace, electronic packaging), long-term aging tests and toxicological evaluations are recommended to avoid potential risks.

The T31 curing agent is a commonly used epoxy resin curing agent. The following are its main components and uses: Main components: The main component of the T31 curing agent is phenolic amine, which is made through a polycondensation reaction of phenol, formaldehyde, ethylenediamine, etc. This complex structure endows the T31 curing agent with unique properties. Main uses: In the coating field: In coatings, the T31 curing agent can undergo a cross-linking reaction with epoxy resin to form a tough, wear-resistant, and corrosion-resistant coating. It is widely applied to anti-corrosion coatings in fields such as ships, bridges, and buildings, and can effectively protect the surface of objects from the erosion of the external environment. In the adhesive field: As a curing agent for epoxy resin adhesives, the T31 can endow the adhesives with good bonding strength and water resistance, and can be used for bonding various materials such as metals, ceramics, and glass. In the composite material field: When manufacturing composite materials, the T31 curing agent can enable better combination between the epoxy resin matrix and fiber-reinforced materials, improve the mechanical properties and stability of the composite materials, and is commonly used in fields such as aerospace and automotive manufacturing. In the electrical insulation field: The epoxy resin cured by the T31 curing agent has good insulation performance and can be used for insulation potting and insulation coatings of electrical equipment to ensure the safe operation of electrical equipment.

What is polyamide curing agent 3115? Polyamide curing agent 3115 is a high molecular weight epoxy resin curing agent with the following characteristics and application fields: -* * Characteristics** -High viscosity: Its viscosity is ≥ 100000pps at 25 ℃, appearing as a light yellow or orange red transparent viscous liquid. -* * Excellent Performance * *: It has excellent water resistance, corrosion resistance, bonding performance, good wettability to color and substrate, and excellent chemical resistance. -* * Longer applicable period * *: After mixing with epoxy resin, it has a longer applicable period and can meet certain construction operation time requirements. -Low comprehensive cost: Stable price, good compatibility with resin, no need for curing, can reduce usage costs and operational difficulties. -* * Technical indicators** -Amine value: 200-220mgKOH/g. -Density: 0.97 ± 0.01 at 25 ℃. -Chromaticity: Orange red. -* * Active hydrogen equivalent * *: 175. -Recommended dosage: For liquid epoxy resin (EEW=190), the recommended dosage per 100 parts of epoxy resin is 100: （80 - 100）。 -* * Application Fields** -Ship anti-corrosion coating: It can provide good anti-corrosion protection for ships and resist the erosion of seawater, sea breeze, etc. -Pipeline anti-corrosion: It can be used for anti-corrosion coating on the surface of pipelines to extend their service life. -* * Bonding, joint filling, grouting, etc. * *: It has good bonding performance and can be used for bonding, joint filling, and grouting operations of various materials, such as repairing and sealing building structures.