Applications and Selection of Polyester Resins in Industrial Coatings: Powder, Coil, Baking, Packaging, and Metal Coating Scenarios
Applications and Selection of Polyester Resins in Industrial Coatings: Powder, Coil, Baking, Packaging, and Metal Coating Scenarios
1. Core Value of Polyester Resins in Coatings
In coating formulation, the key to selecting a resin is determining whether it can meet the critical performance requirements of the intended application. Polyester resins are widely used in powder coatings, coil coatings, industrial baking finishes, packaging coatings, and general industrial metal coatings because they can achieve a relatively good balance among appearance, adhesion, hardness, flexibility, weatherability, application properties, and cost.
The main value of polyester resins in coatings can be summarized as follows:
Performance Area | Application Value |
Adhesion | Usually provides good adhesion to properly pretreated metal substrates such as steel sheet, aluminum, galvanized steel, and tinplate |
Mechanical properties | Helps achieve a balance among hardness, flexibility, impact resistance, and formability |
Appearance | Supports good flow and leveling, film build, gloss, and decorative appearance |
Process adaptability | Can be used in multiple systems, including powder coatings, coil coatings, baking finishes, high-solids coatings, waterborne coatings, and polyurethane systems |
Weatherability | Polyester systems designed for outdoor use usually offer good gloss retention, color retention, and UV resistance |
Environmental performance | In powder, high-solids, and waterborne systems, helps reduce volatile organic compound emissions |
Industrial application | Mature processing technology and stable performance, suitable for large-scale industrial coating operations |
Whether a polyester resin is suitable for a particular coating system should be judged from the perspective of the application scenario. Common application scenarios are shown below:
Application Scenario | Key Considerations When Selecting Polyester |
Powder coatings | Melt flow and leveling, storage stability, mechanical properties, weatherability, low-VOC processing |
Coil coatings | High-speed roller coating, rapid baking, T-bend performance, post-forming performance, adhesion |
Industrial baking finishes | Appearance, hardness, flexibility, solvent resistance, application stability |
Packaging coatings | Flexibility, retort resistance, resistance to contents, food-contact compliance |
General industrial metal coatings | Adhesion, application efficiency, cost, appearance, and basic protection |
2. Types of Polyester Resins and Curing Systems
“Polyester resin” in coatings does not refer to a single product. Different polyester resins vary significantly in acid value, hydroxyl value, glass transition temperature, molecular weight, viscosity, functionality, and curing mechanism, and therefore differ in their suitable applications.
Classification Dimension | Typical Types | Significance for Selection |
Functional group | Carboxyl-functional polyester, hydroxyl-functional polyester | Determines compatibility with curing agents such as TGIC, HAA, amino resins, and isocyanates |
Main-chain structure | Saturated polyester, unsaturated polyester | Affects weatherability, flexibility, reaction mechanism, and main application areas |
Application form | Polyester for powder coatings, polyester for coil coatings, polyester for packaging coatings, polyester polyol | Determines glass transition temperature, viscosity, molecular weight, curing window, and testing requirements |
Modification method | Silicone-modified, acrylic-modified, polyurethane-modified, etc. | Used to improve weatherability, hardness, flexibility, adhesion, or special performance properties |
In practical coating systems, the relationship between common polyester systems and curing methods can be summarized as follows:
Polyester System | Commonly Matched Systems | Main Application Areas |
Carboxyl-functional polyester | Triglycidyl isocyanurate (TGIC); hydroxyalkyl amide (HAA); glycidyl ester curing agents | Powder coatings, especially outdoor powder coatings and architectural powder coatings |
Hydroxyl-functional polyester | Amino resins, blocked isocyanates, isocyanate curing agents | Industrial baking finishes, polyurethane coatings, high-performance industrial coatings |
Saturated polyester for coil or packaging applications | Amino resins, phenolic resins, isocyanates, etc. | Coil coatings, packaging coatings, industrial baking coatings |
Modified polyester | Silicone-modified, acrylic-modified, polyurethane-modified, etc. | Highly weatherable coil coatings, architectural metal coatings, specialty industrial coatings |
Polyester polyol | Aliphatic or aromatic isocyanates | Polyester-based polyurethane coatings, transportation coatings, and high-performance industrial coatings |
The above classifications are not mutually exclusive. For example, saturated polyester used in coil or packaging coatings may also contain hydroxyl functionality; polyester polyols can also be understood as an important form of hydroxyl-functional polyester in polyurethane systems.
3. Powder Coatings: How Polyester Balances Leveling, Mechanical Properties, and Weatherability
Powder coatings are one of the most important application areas for polyester resins. Powder coatings are typically composed of resin, curing agent, pigments and fillers, and additives. After electrostatic spraying, they are heated to melt, flow, level, and cure into a coating film. Because powder coatings do not use organic solvents as the main application carrier, they offer a clear advantage in reducing VOC emissions. It should be noted, however, that low VOC does not mean there are no occupational health risks. Uncured powder is still a dust system that requires control. Powders containing TGIC, TMA, certain pigments, or isocyanate-containing components should be managed with appropriate ventilation, dust control, and personal protection according to SDS information, occupational exposure requirements, and local regulations.
Polyester powder coatings are commonly used for architectural aluminum profiles, outdoor metal parts, appliance housings, metal furniture, office equipment, lighting fixtures, shelving, and general hardware.
3.1 Requirements of Powder Coatings for Polyester Resins
Powder Coating Requirement | Corresponding Resin Performance Focus |
Storage stability at room temperature | The resin should have an appropriate glass transition temperature and softening behavior to reduce powder caking and facilitate transportation, storage, and application |
Ability to melt and form a film upon heating | The resin should fully melt under baking conditions and form a continuous coating film |
Proper flowability in the molten state | The melt viscosity and flow behavior of the resin should match the requirements for leveling, film build, and appearance |
Formation of a crosslinked structure after curing | The resin functional groups and curing agent must be compatible to achieve hardness, chemical resistance, and mechanical properties |
UV and hot-humidity resistance for outdoor systems | The resin structure, curing system, and pigment system should jointly support gloss retention, color retention, and adhesion retention |
Good compatibility with pigments, fillers, and additives | Helps ensure hiding power, dispersion, leveling, appearance, and application stability |
3.2 Why Pure Polyester Systems Are Commonly Used in Outdoor Powder Coatings
The term “pure polyester powder” here is used relative to polyester/epoxy hybrid powder coatings. It refers to a powder coating system in which polyester is the main film-forming resin and is crosslinked with TGIC, HAA, or glycidyl ester curing agents. It does not mean that polyester is the only component in the formulation.
Outdoor powder coatings must withstand long-term exposure to ultraviolet light, rain, hot and humid conditions, temperature fluctuations, and pollutants. Compared with epoxy powder coatings, polyester powder systems designed for outdoor use usually provide better gloss retention, color retention, and weatherability. Therefore, pure polyester powder systems are commonly used for architectural aluminum profiles, outdoor guardrails, metal curtain walls, and general outdoor metal components.
It should be noted that “pure polyester powder” does not mean that all polyester powder coatings are suitable for long-term outdoor exposure. Actual weatherability depends on the grade of polyester resin, curing agent system, pigment weatherability, film thickness, metal pretreatment, adequacy of baking, and target application standard. Ordinary outdoor, architectural-grade, high-weatherability, and super-durable polyester powder coatings should be selected differently.
3.3 Why Polyester Is Also Used in Indoor Powder Coatings
Indoor powder coatings have relatively lower weatherability requirements, but they are more sensitive to appearance, hardness, stain resistance, scratch resistance, impact resistance, and cost. Polyester/epoxy hybrid powder coatings are commonly used for indoor metal products such as appliance housings, office furniture, display racks, and machinery housings.
In these systems, polyester mainly provides flexibility, leveling, and overall mechanical performance, while the epoxy component helps improve adhesion, hardness, and chemical resistance. Polyester/epoxy hybrid powder coatings are generally suitable for indoor applications.
3.4 Key Selection Points for Powder Polyester
Application Area | Common Choice | Main Evaluation Factors |
Outdoor architectural components | Weatherable pure polyester powder | Weatherability, gloss and color retention, adhesion, impact resistance |
Indoor metal parts | Polyester/epoxy hybrid powder | Appearance, hardness, cost, application stability |
Appliance housings | Polyester or polyester/epoxy hybrid powder | Appearance, impact resistance, stain resistance, edge coverage |
Low-temperature curing requirements | Low-temperature-curing polyester system | Curing temperature, leveling, storage stability |
4. Coil Coatings: How Polyester Balances Post-Forming Performance and Adhesion
Coil coating refers to a process in which steel or aluminum sheet is continuously cleaned, pretreated, coated, baked, and recoiled before forming. The coated metal is then cut, bent, stamped, roll-formed, or profiled. Coil coating is a continuous, high-efficiency metal pre-coating process.
Coil coatings are commonly used for building roofing panels, exterior wall panels, appliance panels, garage doors, metal ceilings, cold-storage panels, and interior decorative metal panels.
4.1 Special Resin Requirements for Coil Coatings
Coil coatings differ from ordinary spray-applied coatings. After coating, they must undergo forming operations, so the resin must meet both coating application requirements and forming performance requirements.
Requirement | Specific Performance |
High-speed application adaptability | Suitable for roller coating, rapid leveling, and rapid baking |
Good adhesion | The coating film does not delaminate after bending or stamping |
Excellent flexibility | Less likely to crack or peel in T-bend testing |
Impact resistance | Resistant to damage during forming, transportation, and assembly |
Solvent resistance | MEK double rubs can reflect curing status and solvent resistance |
Appearance stability | Suitable for color, gloss, and film thickness control in continuous production |
Notes:
The T-bend test is an important method for evaluating the formability of coating films in coil coatings. ASTM D4145 is used to evaluate the flexibility and adhesion of organic coatings on prepainted metal sheet after bending deformation.
Methyl ethyl ketone (MEK) rubs are commonly used to rapidly evaluate the solvent resistance and curing status of a coating film. However, the results are affected by solvent type, number of rubs, rubbing pressure, film thickness, temperature and humidity, and the evaluation method. MEK rubs alone should not be equated with complete cure, nor can they represent the coating film’s resistance to all chemical media.
4.2 Why Polyester Is Suitable for Coil Coatings
Polyester resin is selected for coil coatings mainly because it can provide a good overall balance among coating efficiency, forming performance, and coating film stability:
Coil Coating Concern | Role of Polyester Resin |
Balance between hardness and flexibility | Helps the coating film obtain surface strength while reducing the risk of cracking during bending or stamping |
Balance between adhesion and post-forming performance | Helps the coating film remain bonded to the metal substrate after forming |
Balance between rapid baking and sufficient cure | Adapts to continuous high-speed production while supporting solvent resistance and coating film stability |
Balance between appearance and protection | The topcoat provides decorative appearance, while the primer and pretreatment jointly support basic protection |
Balance between cost and durability | Suitable for designing different grades of coil coatings for building panels, appliance panels, and ordinary industrial sheet materials |
Polyester resins are usually used in coil coating topcoats, and may also be used in primers and backcoats. For architectural coil coatings, weatherability, color stability, corrosion resistance, and adhesion should be prioritized. For appliance coil coatings, appearance, hardness, stain resistance, T-bend performance, and impact resistance should be emphasized. For highly formable sheet materials, flexibility and adhesion after forming are key considerations.
5. Industrial Baking Finishes and General Metal Coatings: Polyester for Appearance, Hardness, and Application Stability
Industrial baking finishes are commonly used for metal products, machinery and equipment, instruments, hardware, lighting fixtures, appliance components, and decorative industrial products. Compared with air-drying coatings at room temperature, industrial baking finishes achieve a higher degree of crosslinking through heat curing, thereby improving hardness, solvent resistance, adhesion, and coating film stability.
5.1 Requirements of Industrial Baking Finishes for Polyester Resins
Industrial baking finishes generally focus on three categories of performance:
Performance Category | Key Indicators |
Appearance and application | Leveling, film build, gloss, color stability, application window |
Mechanical properties | Hardness, adhesion, flexibility, impact resistance |
Durability | Solvent resistance, chemical resistance, hot-humidity resistance, stain resistance |
Hydroxyl-functional polyester or saturated polyester can be used with amino resins, blocked isocyanates, and other curing agents to form crosslinked coating films. These systems can achieve a good balance among appearance, hardness, flexibility, adhesion, and chemical resistance.
5.2 Typical Advantages of Polyester Baking Finishes
Performance | Advantages of Polyester Baking Finishes |
Appearance | Good leveling and film build, suitable for high-gloss, semi-gloss, matte, and colored systems |
Hardness | High hardness can be achieved after baking and crosslinking |
Flexibility | Can withstand certain bending, stamping, and assembly deformation |
Adhesion | Good adaptability to properly pretreated metal substrates |
Solvent resistance | Good performance when sufficiently cured |
Production stability | Suitable for batch industrial coating and automated production |
5.3 Polyester Applications in General Metal Products
General industrial metal coatings cover a broad range of applications, including machinery housings, hardware, lighting fixtures, tools, shelving, metal doors and windows, electrical cabinets, and decorative metal parts. Polyester is selected for these applications mainly because:
① It provides good appearance, gloss, and leveling;
② It offers good adhesion to treated metal substrates;
③ It can balance hardness, flexibility, and impact resistance;
④ It can be used in powder coatings, baking finishes, and high-solids systems;
⑤ Its cost and application efficiency are suitable for large-scale production.
If the coating is exposed for a long time to severe corrosion, strong alkali, continuous immersion, high-temperature chemical media, or heavy-duty anticorrosion environments, a simple polyester topcoat is usually not a complete solution. Polyester can be part of a metal protection system, but it should not be equated with a heavy-duty anticorrosion system. These applications usually require epoxy primers, zinc-rich primers, polyurethane topcoats, fluorocarbon topcoats, or other high-protection systems, together with consideration of substrate pretreatment, dry film thickness, intercoat adhesion, edge coverage, and maintenance cycle. The advantages of polyester lie more in appearance, flexibility, weatherability, and application adaptability, while corrosion protection should be evaluated within the complete coating system.
6. Packaging Coatings: How Polyester Meets Requirements for Flexibility, Retort Resistance, and Compliance
Packaging coatings, especially internal coatings for metal packaging, impose high requirements on resin and formulation systems. Food cans, beverage cans, bottle caps, easy-open ends, and general metal packaging usually require the coating to meet adhesion, flexibility, resistance to contents, retort resistance, and food-contact compliance requirements at relatively low film thickness.
Traditional bisphenol A-based epoxy internal can coatings were long used for metal food and beverage cans. However, due to toxicological concerns, consumer concerns, and regulatory changes, coating technologies that do not use or do not intentionally add bisphenol A continue to develop, including polyester, acrylic, and other resin systems.
It should be noted that “BPA-NI” usually means that BPA is not intentionally added to the formulation. It does not mean absolute absence of BPA under all regulatory and testing scenarios. Whether a packaging internal coating is compliant still needs to be judged comprehensively based on target market regulations, overall migration, specific migration, non-intentionally added substance assessment, sensory testing, and declaration of compliance.
6.1 Requirements of Packaging Coatings for Polyester Systems
Requirement | Description |
Excellent adhesion | The coating film must firmly adhere to the metal surface |
High flexibility | Must withstand can making, seaming, drawing, stamping, and closure forming |
Retort resistance | Must withstand sterilization and heat treatment |
Resistance to contents | Resistant to acidic, salty, oily, alcoholic, and other contents |
Low migration risk | Must meet food-contact regulations and migration testing requirements |
Corrosion resistance | Prevents reaction between the metal and the packaged contents |
Flavor stability | Minimizes odor, migration, and changes in the flavor of the contents |
The difficulty of internal coatings for food packaging lies in the fact that the coating film must withstand severe deformation during can making while maintaining continuity, density, and stable adhesion under the effects of the contents and high-temperature sterilization.
6.2 Role of Polyester Systems in Packaging Coatings
Polyester is used in packaging coatings mainly for the following reasons:
① It can provide good flexibility and processability;
② It offers good adhesion to treated metal substrates;
③ Resistance to contents can be improved through resin structure and formulation design;
④ It can be used in coating systems designed without intentional addition of bisphenol A;
⑤ It can adapt to high-solids and waterborne formulation directions;
⑥ Its performance can be adjusted according to the requirements of food cans, beverage cans, ends, and general metal packaging.
7. Key Factors in Selecting Polyester Resins
Actual selection can be approached through the following four questions.
7.1 What Are the Substrate and Pretreatment?
It is necessary to determine whether the substrate is cold-rolled steel, galvanized steel, aluminum, tinplate, tin-free steel, plastic, or a composite material. Different substrates have different requirements for adhesion, pretreatment, primer, and curing temperature. For metal coating, it is also important to consider whether phosphating, zirconium-based treatment, silane treatment, chromating, or chromium-free pretreatment is sufficient. Many coating failures are caused by insufficient substrate cleaning, pretreatment, primer compatibility, or curing conditions.
7.2 What Is the Application Process?
It is necessary to determine whether the coating is applied by powder spraying, roller coating, air spraying, electrostatic spraying, or dip coating; whether it dries at room temperature, cures at medium-low temperature, or undergoes high-temperature baking; and whether it is used in continuous production or batch production. The application process determines resin form, viscosity, glass transition temperature, curing temperature, reaction activity, and leveling requirements. For example, powder coatings require attention to storage stability and melt flow/leveling, coil coatings require attention to rapid baking and post-forming performance, and industrial baking finishes require attention to the baking window and application stability.
7.3 What Is the Service Environment?
It is necessary to determine whether the coating will be used indoors or outdoors, and whether it will be exposed for long periods to ultraviolet light, high humidity, salt spray, acid rain, industrial pollutants, cleaning agents, oils, solvents, food contents, or high-temperature retorting. The service environment determines the requirements for weatherability, water resistance, chemical resistance, corrosion protection, and mechanical durability. Outdoor architectural coatings should focus on weatherability and color retention; packaging internal coatings should focus on resistance to contents and migration; and industrial metal coatings should determine whether primers and multilayer protective systems are needed based on corrosion category and expected service life.
7.4 Key Performance Indicators
Different application scenarios have different requirements for coating film performance, application process, and service environment. Key performance indicators should be clarified first, and then the suitability of the resin should be judged based on formulation and test results.
Application Area | Key Performance Indicators |
Outdoor powder coatings | Storage stability, melt flow and leveling, weatherability, adhesion, impact resistance |
Indoor powder coatings | Appearance, hardness, stain resistance, cost, application stability |
Coil coatings | T-bend, impact resistance, adhesion, solvent resistance, rapid baking and sufficient cure |
Industrial baking finishes | Appearance, hardness, flexibility, chemical resistance, application window |
Packaging coatings | Flexibility, retort resistance, resistance to contents, migration testing, food-contact compliance |
General metal coatings | Adhesion, hardness, impact resistance, cost, basic protection and decorative performance |
High-performance industrial coatings | Mechanical properties, weatherability, chemical resistance, media resistance, system compatibility |
Determining whether a polyester resin is suitable requires coating film performance verification in combination with the actual formulation, substrate, and application conditions. Common test items include:
Verification Area | Typical Tests or Evaluation Items |
Mechanical and forming properties | Adhesion, pencil hardness, impact resistance, bending, T-bend |
Cure and solvent resistance | MEK rubs, gel time, curing window or baking window |
Durability and protection | Salt spray, hot-humidity exposure, artificial accelerated weathering, gloss retention, color difference |
Resistance to service media | Stain resistance, resistance to cleaning agents, resistance to oils, resistance to contents |
Application and process stability | Leveling, pinholes, edge coverage, storage stability |
Food-contact-related performance | Overall migration, specific migration, screening or assessment of non-intentionally added substances, sensory testing, adhesion after retorting |
8. Representative Chemical Classification Tables Related to the Application and Selection of Polyester Resins in Industrial Coatings （Tables 1–5）
Note: The representative chemicals listed below are mainly used for polyester resin synthesis, curing mechanism research, formulation screening, performance evaluation, and laboratory development. Actual selection for industrial coatings should also be confirmed based on resin grade, product SDS/COA, hazardous chemical management requirements, VOC requirements, target standards, and application conditions.
Table 1. Monomers and Structure-Regulating Raw Materials for Polyester Resin Synthesis
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Dicarboxylic acid monomer | 111-20-6 | Sebacic acid | Chemically pure (CP), ≥98% | Used in the synthesis of aliphatic polyesters. It can adjust resin flexibility, low-temperature performance, and coating film processability, and is suitable for research on coil coatings, packaging coatings, and flexible industrial coatings. | |
Dicarboxylic acid monomer | 110-15-6 | Succinic acid | PharmPure™, ChP, JP, ACS, NF, crystalline | Used in polyester resin structure design. It can introduce aliphatic chain segments and is suitable for research on flexibility, adhesion, and bio-based polyester coatings. | |
Aromatic dicarboxylic acid monomer | 121-91-5 | Isophthalic acid (IPA) | AR, ≥99% | Used in the synthesis of saturated polyester and powder polyester resins. It can improve resin weatherability, hardness, chemical resistance, and overall coating film performance. | |
Cycloaliphatic diol monomer | 105-08-8 | 1,4-Cyclohexanedimethanol (CHDM) | ≥99%, mixture of cis and trans | Used in the synthesis of high-performance polyester resins. It can improve coating film hardness, flexibility, hydrolysis resistance, and weathering stability, and is suitable for powder coatings, coil coatings, and industrial baking finish systems. | |
Branched diol monomer | 126-30-7 | Neopentyl glycol (NPG) | ≥99% | Used in the synthesis of weatherable polyester resins. It can improve hydrolytic stability, weatherability, leveling, and mechanical properties, and is commonly used in resin design for powder coatings and coil coatings. | |
Bio-based diol monomer | 652-67-5 | Isosorbide | ≥98% (GC) | Used in research on bio-based polyesters and high-glass-transition-temperature polyesters. It can improve resin rigidity, thermal performance, and low-migration coating design. | |
Bio-based dicarboxylic acid monomer | 3238-40-2 | 2,5-Furandicarboxylic acid (FDCA) | ≥98% | Used in the synthesis of bio-based polyester resins. It can be used in research on chemical resistance, barrier properties, and alternative packaging coating systems. | |
Cycloaliphatic anhydride monomer | 85-42-7 | 1,2-Cyclohexanedicarboxylic anhydride | ≥97%, cis + trans | Used in the synthesis of cycloaliphatic polyester, alkyd, or modified polyester resins. It can adjust hardness, flexibility, water resistance, and reactivity in baking systems. |
Table 2. Curing Agents, Crosslinkers, Catalysts, and Powder Coating Additives
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Polyisocyanate curing agent | 28182-81-2 | Poly(hexamethylene diisocyanate) (PolyHDI) | Viscosity 900–1500 cP (25 °C) | Used for curing hydroxyl-functional polyester and polyester polyols. It can be used to prepare polyurethane-type industrial coatings and for research on weatherable, chemically resistant, and high-performance metal coatings. | |
Isocyanate monomer | 822-06-0 | Hexamethylene diisocyanate (HDI) | Moligand™, ≥99% | Used in reactions with polyester polyols and in polyurethane coating synthesis. It can be used for research on curing reactions, crosslink density, and coating film chemical resistance. | |
Epoxy crosslinking component | 1675-54-3 | Bisphenol A diglycidyl ether (BADGE) | Moligand™, ≥85% | Used in research on epoxy coatings, internal can coatings, and modified systems. It can be combined with polyester, phenolic, or other resin systems to evaluate adhesion, resistance to contents, and crosslinked structure. | |
Acid catalyst | 27176-87-0 | Dodecylbenzenesulfonic acid in isopropanol, catalyst solution | 70 wt. % in isopropanol | Used as a curing catalyst for amino baking finishes and polyester–amino systems. It can be used to adjust baking temperature, curing speed, solvent resistance, and coating film hardness. | |
Cycloaliphatic isocyanate | 4098-71-9 | Isophorone diisocyanate, mixture of isomers (IPDI) | ≥99% | Used for curing polyester polyols and in research on weatherable polyurethane coatings. It can be used to evaluate outdoor industrial coatings, mechanical properties, and yellowing stability. | |
Amino crosslinker | 3089-11-0 | 2,4,6-Tris[bis(methoxymethyl)amino]-1,3,5-triazine | ≥98% (HPLC) | Used for curing hydroxyl-functional polyester baking finishes and coil coatings. It can increase crosslink density, hardness, solvent resistance, and stability of baked coating films. | |
Acid catalyst | 104-15-4 | 4-Toluenesulfonic acid | ≥98% | Used as a catalyst in polyester–amino baking systems. It can be used to evaluate curing speed, MEK rub resistance, hardness, and coating film chemical resistance. | |
Powder coating curing agent | 2451-62-9 | Triglycidyl isocyanurate | ≥98% | Used for curing carboxyl-functional polyester powder coatings. It can be used in research on outdoor powder coatings, architectural powder coatings, gloss and color retention, and mechanical properties. | |
Powder coating curing agent | 6334-25-4 | N,N,N',N'-Tetrakis(2-hydroxyethyl)adipamide | ≥97% | Used in TGIC-free curing systems for carboxyl-functional polyester powder coatings. It can be used in research on low-yellowing, weatherable, and decorative powder coatings. | |
Polyisocyanate curing agent | 3779-63-3 | 1,3,5-Tris(6-isocyanatohexyl)-1,3,5-triazinane-2,4,6-trione | ≥95% | Used for curing hydroxyl-functional polyester and polyurethane coatings. It can be used to evaluate weatherable coatings, crosslinked structures, hardness, and chemical resistance. | |
Organotin catalyst | 77-58-7 | Dibutyltin dilaurate (DBTDL) | ≥95% | Used as a catalyst for the reaction between isocyanates and hydroxyl-functional polyester. It can be used in research on polyurethane coating curing rate, reaction activity, and coating film performance. | |
Powder coating additive | 119-53-9 | Benzoin | ≥99.5% | Used for degassing and pinhole control in powder coatings. It can be used to evaluate leveling, film surface appearance, and baking defects in polyester powder coatings. |
Table 3. Solvents, Diluents, Film-Formation Modifiers, and Test Media
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Aromatic solvent | 1330-20-7 | Xylene | Premium grade reagent, ≥99%, xylene isomers and ethylbenzene | Used in solvent-based polyester coatings, industrial baking finishes, and resin dilution systems. It can be used for research on solubility, application viscosity, and leveling performance. | |
Ketone solvent and test medium | 78-93-3 | B1506362 | Methyl ethyl ketone, regulated precursor chemical | For HPLC, ≥99.7% | Used for coating resin dissolution, cleaning, and MEK rub testing. It can be used to evaluate the curing status and solvent resistance of polyester baking coating films. |
Ester solvent | 123-86-4 | Butyl acetate | Anhydrous, ≥99% | Used in solvent-based polyester baking finishes, coil coatings, and industrial coating systems. It can adjust evaporation rate, leveling, and application window. | |
Ketone solvent | 108-94-1 | Cyclohexanone | ≥99.8% | Used for dissolving polyester resins and coating formulations. It can be used in research on high-boiling solvent systems, film formation, and leveling performance. | |
Alcohol-ketone solvent | 123-42-2 | Diacetone alcohol | Chemically pure (CP), ≥98% | Used for coating formulation dilution, leveling, and film-formation adjustment. It can be used in research on the application performance of waterborne or solvent-based polyester systems. | |
Glycol ether solvent | 111-76-2 | Ethylene glycol monobutyl ether (EB) | Standard for GC, ≥99.5% (GC) | Used as a co-solvent in waterborne polyester, baking coating, and industrial coating systems. It can improve film formation, wetting, and application stability. | |
Glycol ether solvent | 107-98-2 | Propylene glycol methyl ether (PGME) | Standard for GC, ≥99.5% | Used in waterborne polyester, coil coating, and baking finish systems. It can adjust evaporation rate, leveling, and resin compatibility. | |
Glycol ether ester solvent | 108-65-6 | P295138 | Propylene glycol methyl ether acetate (PMA) | ≥99.5% | Used in solvent-based polyester baking finishes, coil topcoats, and industrial coatings. It can be used to adjust leveling, orange-peel control, and application window. |
Table 4. Pigments, Fillers, Anticorrosive Pigments, and Inorganic Functional Components
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
White pigment | 13463-67-7 | Titanium dioxide (IV) | Premium grade, ≥99% | Used in polyester powder coatings, coil topcoats, and industrial baking finishes. It can provide hiding power, whiteness, gloss, and decorative appearance. | |
Green inorganic pigment | 1308-38-9 | Chromium(III) oxide | Extra-dry grade | Used in weatherable polyester coatings and industrial metal coatings. It can provide green coloration, heat resistance, and outdoor color stability. | |
Inorganic filler | 7631-86-9 | Silicon dioxide | PrimorTrace™, ≥99.99% metals basis, particle size: 2 μm | Used in polyester coatings for matting, reinforcement, rheology control, and scratch resistance research. It can adjust the surface state of the coating film. | |
Inorganic filler | 7727-43-7 | Barium sulfate | PrimorTrace™, ≥99.99% metals basis | Used for filling, gloss adjustment, and volume pigment design in polyester coatings. It can improve coating film compactness, chemical resistance, and cost structure. | |
Anticorrosive pigment | 13939-25-8 | Aluminum tripolyphosphate | P₂O₅ content 60–70% | Used in anticorrosive systems for metal coatings. It can be used in salt spray resistance research for polyester primers, coil primers, and general industrial metal coatings. | |
Inorganic filler | 471-34-1 | Calcium carbonate | AR, ≥99% | Used for filling, cost adjustment, and coating film hardness control in polyester coatings. It can be used in formulation research for powder coatings and general industrial coatings. | |
Anticorrosive pigment | 7779-90-0 | Zinc phosphate hydrate | AR, ≥99% | Used in metal anticorrosive coatings and polyester-compatible primers. It can be used to evaluate adhesion, salt spray resistance, and corrosion inhibition performance. | |
Anticorrosive functional pigment | 13767-32-3 | Zinc molybdate | ≥99.9% metals basis | Used in anticorrosive coatings and metal primer systems. It can be used in research on corrosion inhibition, hot-humidity resistance, and protective systems combined with polyester topcoats. | |
Weatherable color pigment | 8007-18-9 | Titanium nickel yellow | — | Used in outdoor polyester powder coatings, coil coatings, and architectural metal coatings. It can provide yellow coloration, heat resistance, and weatherable color stability. |
Table 5. Surface-Functional, Wear-Resistant, and Specialty Functional Materials
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Thermoplastic resin material | 9002-88-4 | Polyethylene (PE) | Medium density, melt index 3.5 g/10 min (190 °C/2.16 kg) | Used in research on coating surface modification, wear resistance, and slip properties. It can be used as a material for polyester coating modification, composite film formation, and performance comparison. | |
Wear-resistant and lubricating additive material | 9002-84-0 | Polytetrafluoroethylene micropowder (PTFE) | Average particle size: 25 μm | Used for surface modification of polyester powder coatings and industrial coatings. It can improve wear resistance, anti-blocking properties, slip, and scratch resistance. | |
Conductive carbon material | 1333-86-4 | C431910 | Graphitized carbon | ≥99.95% metals basis, nanopowder, graphitized, <500 nm particle size (DLS) | Used in research on functional polyester coatings and conductive coatings. It can adjust conductivity, wear resistance, color, and surface functionality. |
Magnetic functional filler | 1309-37-1 | F141282 | Nano magnetic iron oxide (γ-Fe₂O₃) | ≥98% metals basis, 10 nm, γ type | Used in functional coatings, magnetic coatings, and composite polyester coating research. It can impart magnetic response, coloration, and inorganic filler reinforcement effects. |
Note: The above are representative Aladdin products. For more product specifications, search by “product name/CAS/catalog number” on the Aladdin website.
References
[1] allnex. TGIC Powder Coating and HAA Polyester Resins.
[2] allnex. Architectural Powder Coating Resins.
[3] European Coil Coating Association. Coil Coating / Prepainted Metal.
[4] National Coil Coating Association. Coil Coating Process.
[5] ASTM International. ASTM D4145, Standard Test Method for Coating Flexibility of Prepainted Sheet.
[6] Evonik. DYNAPOL® Polyester Resins.
[7] Food Packaging Forum. Can Coatings.
[8] European Commission. Commission Regulation (EU) 2024/3190 on the use of bisphenol A and other bisphenols and bisphenol derivatives in certain materials and articles intended to come into contact with food.
[9] PPG. PVDF versus SMP Coil Coating Systems.
[10] Luo, Y.; et al. Effects of Different Polyols with Functions on the Properties of Polyester-Based Polyurethane Coatings. Coatings, 2025, 15, 61.
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