Hot melt adhesive is everywhere in industrial production and daily life—serving as the "invisible connector" from sealing快递 bags and bonding cardboard boxes quickly, to precise adhesion in DIY crafts, to composite assembly in automotive interiors.

But with so many hot melt adhesive options available, have you ever wondered: which one should you choose? Why do some withstand high temperatures while others melt at the slightest heat? Why are some designed for plastics, while others are made specifically for fabrics?

This time, we'll break down hot melt adhesives across three key dimensions—form, base material (substrate), and application—to help you build a clear understanding and select the right product without mistakes.

1. By Shape: Shape Determines Usage

The physical form of hot melt adhesive directly determines its application tools and suitable scenarios. The four most common types are as follows:

1. Granular (pellets)

● Features: Compact size and excellent flowability, ideal for automated feeding.

● Usage: Feed into an industrial hot-melt machine and apply via spray gun, roller coating, or刮涂.

● Application Scenarios: High-volume continuous production, such as rapid carton sealing, book binding with graphics and text, and filter frame adhesive bonding.

2. Stick (glue stick)

● Features: Standardized cylindrical shape with uniform diameter and length for easy dispensing.

● Usage: Works with handheld hot glue guns; squeeze the trigger to dispense glue.

● Use cases: Handmade DIY, home repairs, small-batch prototyping, and exhibition setup—ideal for applications requiring high flexibility.

3. Block (Brick)

● Features: Large-volume solid form, typically in rectangular or pillow packages; stable flowability after melting.

● Usage: Place in a large-capacity high-temperature glue pot or tank coater for uniform heating, then apply via dip coating, curtain coating, or knife coating.

● Applications: Packaging & boxing, bookbinding & printing, medical supplies, automotive interiors, footwear & textiles, woodworking & furniture, electronics & home appliances

II. By Ingredient: The Core of Performance

The "substrate" is the soul of hot melt adhesive performance. Different polymer systems impart distinct thermal resistance, strength, and flexibility to the adhesive.

1. EVA

● Key Features: Best value, fast curing, strong initial tack, customizable color.

● Advantages: Low cost, easy to process, and highly versatile.

● Limitations: Moderate heat resistance (typically < 70°C); not oil-resistant and unsuitable for prolonged high-temperature exposure.

● Typical applications: book binding, carton sealing, glue stick manufacturing, and initial adhesion of shoe materials.

2. PO (Polyolefin)

● Key Features: Excellent weather resistance, strong adhesion to plastics and metals, and superior flexibility.

● Advantages: Water-, oil-, and chemical-resistant with superior aging resistance compared to EVA.

● Typical applications: appliance edge banding, automotive interiors, filters, and outdoor building materials.

3. PA (Polyamide)

● Key Features: The ultimate high-temperature performer with a softening point of 150–200°C, offering high strength and resistance to oil and solvents.

● Advantage: Maintains bonding performance at high temperatures, ideal for harsh environments.

● Limitations: High cost and requires high-temperature melting (180–220°C).

● Typical Applications: Automotive filters, premium garment linings, electronic component encapsulation, and metal structure bonding.

4. PES (Polyester)

● Key Features: Balanced performance, excellent heat resistance, strong creep resistance, and high elastic recovery.

● Advantages: Excellent adhesion to metals, plastics, wood, and other materials; superior overall performance.

● Typical Applications: Automotive interior panel lamination, footwear materials, bonding of refrigerator/washing machine components, and aluminum-plastic composite panels.

5. SBC (hot-melt pressure-sensitive adhesive)

● Key Features: Maintains permanent viscoelasticity at room temperature with instant adhesion under light pressure (pressure-sensitive); becomes flowable for coating when heated to 160~180°C, then regains pressure-sensitive tack upon cooling. Contains 100% solids and is solvent-free.

● Advantages: Extremely high initial tack for instant bonding; excellent wetting on plastics, paper, metals, and skin; wide formulation range enabling peel forces from removable to permanent; VOC-free, eco-safe, and compliant with medical/food-contact standards.

● Typical Applications: Packing tape, double-sided tape, pressure-sensitive labels, and electronic shipping labels; tabs for diapers and adhesive strips for sanitary pads; bandages, IV dressings, and plaster backings; phone screen protectors and removable wall decals.

3. By Use Case: Targeted Applications

Based on final functional requirements, hot melt adhesive can also be categorized by application scenario.

● Wrapper Classes:Based on EVA or PO granules; emphasizes rapid curing, high efficiency, and low cost. Ideal for cardboard boxes, beverage packaging, and sealing快递 bags.

● Bookbinding Services:Specialized EVA glue: flexible and fatigue-resistant to ensure pages stay intact during repeated folding.

● Hygiene Products:For diapers, sanitary pads, and similar products. Commonly uses SBC (hot melt pressure-sensitive adhesive) with low melting point, softness, non-irritating properties, and high hygiene standards.

● Textile & Apparel:Uses more PA, TPU, or PES films/powders to balance bonding strength with wearing comfort, and ensures durability against washing and dry cleaning.

● Furniture & Building Materials:Edge banding adhesives and lamination glues, commonly made from EVA or PO, must be formaldehyde-free, heat-resistant, and scratch-resistant to meet environmental standards.

● Electronics & Automotive:Premium applications commonly use PA, PES, and PO, emphasizing high-temperature resistance, insulation, low volatility, and long service life.

IV. How to Choose Quickly: A 3-Step Guide

When starting a new project, how do you choose the right hot melt adhesive? Follow these three steps:

1. View Scenarios:Is it industrial automation or manual operation? Decide whether to select pellets, glue sticks, or glue blocks.

2. View materials:What to bond? Plastic, metal, fabric, or composite materials? Select the substrate type.

3. View Environment:Is it exposed to high heat, humidity, bending, or stretching? These factors determine the performance grade (e.g., temperature resistance, elasticity, strength).

Hot melt adhesives are not a one-size-fits-all product; they are a highly segmented, performance-diverse family of materials. Mastering the three-dimensional classification of "Formulation—Composition—Application" allows you to easily understand the unique characteristics of every hot melt adhesive.