Adhesives play a crucial role in the assembly and manufacturing of air, oil, water, and HVAC filters and will determine the structural integrity of filters, their performance and longevity. However, the end cap bonding process in filter manufacturing presents unique challenges that demand specialized adhesive solutions. This blog provides essential insights into selecting the best adhesive for your specific applications, focusing on end cap bonding adhesive technologies and potting materials.
Solution for filtration industry
Adhesive Requirements for End Caps in Filters
End caps play a vital role in the structural integrity of filters, serving not only to hold the filter components together but also to maintain the necessary spacing between pleats for optimal airflow and filtration efficiency.
To ensure the longevity and performance of these filters, it’s essential to use adhesives that can withstand high temperatures and exposure to various chemicals.
In many applications, the temperatures that adhesives must resist range from 250°F to 400°F. This thermal resilience is critical, as filters are often subjected to extreme operating conditions that can compromise adhesive bonds if not properly addressed.
Additionally, filters encounter a wide array of chemicals that can affect adhesive performance. Some typical substances that adhesives may come into contact with include:
- Motor, hydraulic, & transmission oil
- Alcohol, acetone, & other organic solvents
- Natural gas, hydrochloric acid, sodium hydroxide
End cap bonding adhesive technologies
Selecting the right adhesive for end cap bonding in filters is essential for ensuring durability and performance across various applications. Each market segment has unique requirements, leading to the use of specific adhesive technologies tailored to meet these demands.
1. Automotive liquid filtration
In automotive liquid filtration, adhesives must exhibit exceptional chemical and high-temperature resistance, as well as rigidity.
Commonly recommended adhesive technologies for this application include:
- Methyl Methacrylate (MMA)
- One or two-part urethane
- One or two-part epoxy
- Modified epoxy
- Hot-melt polyamide
2. Automotive engine and high-temperature industrial air filtration
Similar to liquid filtration, the adhesive requirements for air filtration in automotive engines and industrial settings focus on high-temperature, and chemical resistance in some cases.
The recommended technologies include:
- Methyl Methacrylate (MMA)
- One or two-part urethane
- One or two-part epoxy
- Modified epoxy
- Hot-melt polyamide
3. Consumable water filtration
Water filtration systems, particularly for consumer use, require adhesives that meet specific safety and performance criteria. Key considerations include fast setting times, low odor, low VOC (volatile organic compounds), and effective end cap bonding to challenging substrates. Most critically, the adhesive must comply with food safety standards to prevent any contamination of potable (drinking) water. Common standards include:
- NSF/ANSI 61: A standard for products in contact with drinking water, ensuring that materials do not introduce contaminants into the water.
- FDA 21 CFR 175.105 or FDA 175.300: A regulation covering the use of adhesives in applications where they may have incidental contact with food or drinking water.
In addition to the listed technologies, recommended materials should be certified under food safety standards, such as specialized two-part urethane or epoxy formulated to meet NSF/ANSI 61 or FDA requirements. Recommended adhesive technologies for this sector include:
See more bonding solution for filter at the blog: Filter bonding – Adhesive, Applications and Technologies
Filter Potting Technologies
Potting of filters is another effective way of maintaining appropriate spacing of filter pleats but does not call for the usage of end caps. These potting compounds tend to be molded to the intended base shape of the filter. Some of these potting compounds can be two-part systems, foamed, or can be molded using low pressure and temperature.
1. Automotive Engine and High-Temperature Industrial Air Filtration
In these demanding applications, potting compounds must exhibit high-temperature resistance, chemical resistance, and, in some cases, gasketing properties. Recommended technologies include:
- Hot melt polyamide
- Two-part urethane
- Two-part epoxy
2. Ambient temperature industrial air filtration
For applications at ambient temperatures, potting adhesives should be lightweight and possess some gasketing properties while ensuring full cure during production. Recommended technologies include:
- Hot melt polyamide
- Two-part urethane
3. Industrial water filtration
When dealing with industrial water filtration, particularly in systems that treat water for human consumption, it is crucial for adhesives to be highly hydrophobic, possess low hardness, and have low VOC content. Additionally, they must be certified to meet food safety standards, such as NSF/ANSI 61, to ensure safe usage in water systems. For applications where clarity is important, transparent potting compounds with the appropriate viscosity should be used to eliminate contamination risks while complying with safety regulations.
The recommended technology for these applications is two-part urethane.
Related article: Polyolefins – Solutions to costly filter Potting Compound
The choice of the appropriate compounds for bonding end cap and filter potting depends on the specific requirements of the application and environmental conditions. Each type of material offers its own advantages and is suited to different demands during the manufacturing and usage processes. With many years of experience in the industrial material, Prostech is ready to assist customers in selecting the right potting compound and providing integrated solutions for production lines to optimize manufacturing efficiency. Contact us for free consultation.
