Hot Melts

EVA, PUR, APAO, PA, PSA, and Polyolefins

100% solid thermoplastic formulations

Hot Melts

Hot melt adhesive (HMA) is a 100% solid, solvent-free thermoplastic or thermosetting polymer system. Unlike traditional water-borne or solvent-based adhesives that rely on the slow evaporation of a carrier fluid to build bond strength, HMAs rely entirely on thermodynamic phase transitions.

At room temperature, the adhesive is a solid, tack-free polymer (often supplied in pellets, pillows, or blocks). When heated above its softening point (typically between 120°C and 200°C), it undergoes a phase change into a low-viscosity, flowable fluid. In this melt phase, the adhesive intimately wets out the micro-roughness of the substrate. As the heat rapidly dissipates into the substrates and surrounding air, the polymer matrix cools, crystallizes, and instantly locks the assembly together with immense cohesive strength

8 products

  • 3M™ Hot Melt Adhesive 3748V-0

    3M™ Hot Melt Adhesive 3748 V0

    • Excellent adhesion
    • Good electrical properties
    • Non-corrosive to metal
  • 3M™ Hot Melt Adhesive 3748Q

    3M™ Hot Melt Adhesive 3748

    • High peel
    • High temperature performance
    • Formulated for bonding low surface energy plastics and coatings
  • 3M™ Hot Melt Adhesive 3762LM

    3M™ Hot Melt Adhesive 3762LM

    • 100% solids, no VOCs
    • Easy to use
    • Fast-setting adhesive obtains strength in seconds
  • 3M™ Hot Melt Adhesive Gun Quadrack™

    3M™ Hot Melt Adhesive Gun Quadrack™

    • Palm trigger reduces hand fatigue during extended dispensing sessions
    • Lightweight at 10 oz with glass-reinforced nylon body for industrial durability
    • Quadrack feed system accepts 5/8" x 8" Q-size sticks to reduce reloading frequency
  • 3M 3747

    3M 3747

    • Dissimilar-Substrate Hot-Melt Bonding
    • Rapid Strength Development in Seconds
    • 45-Second Open Time
  • BOSTIK H2315-02

    BOSTIK H2315-02

    • Hot-Melt Pressure-Sensitive Bonding
    • High-Shear High-Temperature Adhesion
    • High-Viscosity Converting Formulation
  • EUREMELT 3413

    EUREMELT 3413

    • 2.8 to 4.0 Pa s Melt Viscosity
    • Flexibility to -35 deg C
    • 23 kV/mm Dielectric Strength
  • BOSTIK 6363

    BOSTIK 6363

    • Wide-Range Hot-Melt Viscosity Control
    • High-Temperature Service Range to 204 deg C
    • Standard 0.5 in Glue-Gun Stick Format

Product selector guide

Product System Application Temperature [°C] Open / Set Time Viscosity [cP] Thermal Rating [°C] Typical Substrates Key Differentiator
3M 3738 Thermoplastic HMA 177–196 ~50 sec ~2,875 @ 191°C ~54 heat resistance Wood, corrugated, chipboard, selected plastics Long bonding range; general assembly
3M 3747 Thermoplastic HMA 177–196 ~45 sec ~4,100 @ 191°C ~63 heat resistance Wood, plastics, fabric, metal Versatile bonding of dissimilar substrates
3M 3747PG Thermoplastic HMA 177–196 ~45–50 sec ~4,100 @ 191°C ~63 heat resistance Wood, plastics, fabric, metal 3747 formulation in PG stick format
3M 3748 Thermoplastic HMA 177–196 ~45 sec ~5,000 @ 191°C ~79 heat resistance LSE plastics, coatings, metals High peel strength on difficult plastics
3M 3748 V-0 Polyolefin HMA 177–196 ~30 sec ~5,000 @ 200°C ~79 heat resistance Electronics, plastics, metals UL 94 V-0 / electrical applications
3M 3762LM Low-melt thermoplastic 121–132 ~25 sec ~4,000 @ 121°C ~54 heat resistance Foam, paper, corrugated, wood Low application temperature
3M 3764-Q Thermoplastic HMA 177–196 ~50 sec ~6,000 @ 191°C ~60 heat resistance PE, PP, PC, PVC, wood, metal Flexible / impact resistant; Q format
3M 3764AE Thermoplastic HMA 177–196 ~50 sec ~6,000 @ 191°C ~60 heat resistance PE, PP, PC, PVC, foam Flexible plastic bonding; AE format
3M 3779TC High-temperature thermoplastic 177–196 ~25 sec ~7,000 @ 191°C ~149 heat resistance Electronics, plastics, wood, metal Very high heat resistance
3M 3792LM EVA low-melt 121–132 ~40 sec ~10,500 @ 121°C ~60 heat resistance Foam, fabric, coated paper, wood Multipurpose low-melt grade
BOSTIK HM4170 Hot melt – verify chemistry — — — — — Current manufacturer data requires verification
Bostik HM7116 Polyester hot melt Verify TDS Moderate ~28,000 @ 215°C ~132 softening point Wood, textiles, vinyl Parent normalized; -98 appears variant / MPN
Bostik Thermogrip 2211 Hot-melt PSA ~163–191 Pressure-sensitive ~8,300 @ 191°C High shear / heat Metals, plastics, foam, trim Current Thermogrip branding
Bostik Thermogrip 6363 EVA hot melt ~163–204 Medium set — — Wood, leather, electronics / assembly Current Thermogrip branding
Bostik Thermogrip 9438 Polyolefin hot melt ~180–200 Extended ~30,000 @ 191°C High heat resistance Automotive / industrial assembly Current Thermogrip branding
Bostik Thermogrip H20182 Hot-melt PSA ~135–177 Pressure-sensitive ~3,000 @ 160°C — Light assembly / converting Parent normalized; E50WIDE appears pack / variant
Bostik Thermogrip H2315-02 Hot-melt PSA ~177–199 Pressure-sensitive ~8,550 @ 191°C ~120 softening point Industrial converting / assembly High-shear, high-temperature HMPSA
DOWSIL HM-2510 Reactive silicone hot melt ~121 Up to 15 min ~110,000 @ 120°C -50 to 150 service Industrial assembly substrates Immediate green strength + moisture cure
DOWSIL HM-2515 Reactive silicone hot melt ~120 Long open time ~27,000 @ 120°C High-temperature silicone Fine beads / lamination Lower-viscosity reactive silicone HM
DOWSIL HM-2520 Reactive silicone hot melt ~120 Long open time ~110,000 @ 120°C High-temperature silicone Industrial assembly High cured tensile performance
DOWSIL HM-2600 Reactive silicone hot melt ~115–135 Long open time ~70,000 @ 120°C High-temperature silicone Industrial assembly Higher-durometer reactive silicone HM
EUREMELT 2888 Polyamide hot melt 200–230 11–31 sec / 1–3 sec set 4,000–6,000 @ 220°C 185–190 softening point PVC, ABS, PC, wood, leather Very fast set; current grade should be supplier-verified
TECHNOMELT 1942 EVA hot melt ~177 ~30 sec ~5,000 @ 177°C ~61 heat resistance Wood, nylon, PC, PVC, ABS, acrylic Current Henkel name; broad plastics adhesion
TECHNOMELT 1X EVA hot melt ~177 ~15 sec ~2,000 @ 177°C ~66 heat resistance Paper, wood, fabric, foam Current Henkel name; fast set on porous substrates

Frequently asked questions

Frequently Asked Questions about Hot Melt Adhesives

How does ambient humidity impact the open time of a PUR hot melt?

Open time is governed strictly by thermodynamics, the cooling rate of the polymer mass, so humidity has minimal effect on open time or physical set time. The secondary crosslinking reaction, however, is entirely dependent on absolute humidity. In highly arid environments, such as winter manufacturing conditions in low-humidity regions, the time required for PUR to reach ultimate crosslink density can double or triple.

Why does PUR equipment require constant purging, whereas EVA tanks do not?

PUR is moisture-reactive. If left dormant at elevated temperatures, or if ambient moisture infiltrates the melt tank or hoses, the isocyanate groups will crosslink inside the equipment, turning the fluid into an irreversible solid. Flushing the system with an inert, non-reactive purging compound, often an EVA or specialized wax, displaces the PUR and neutralizes residual NCO groups before the equipment is shut down.

What causes "stringing" or "tailing" at the dispensing nozzle, and how is it corrected?

Stringing occurs when the polymer fails to cleanly shear and snap off after the dispensing valve closes. It is governed by the polymer's molecular weight distribution (MWD) and extensional rheology. Polymers with ultra-high-molecular-weight fractions retain excessive elastic memory. If lowering the viscosity through a slight temperature increase or increasing nozzle shear does not fix it, the formulation is often the underlying cause. Metallocene polyolefins (mPOs) virtually eliminate tailing because their single-site catalysis yields a precise, narrow MWD that lacks those ultra-long elastic chains.

Can application temperature be increased to reduce the viscosity of a high-molecular-weight PUR?

Only within tight margins. While all hot melt adhesives exhibit pseudo-plastic thinning at higher temperatures, exceeding the manufacturer's recommended pot temperature, usually capped around 140–150°C for PUR, accelerates thermal degradation and premature crosslinking. Rather than drastically raising the temperature, engineers should use heated hoses and precisely calibrated gear pumps to manage high-viscosity fluids.

Learn more

Hot Melt Adhesives – Chemistry & Technology Overview

Understanding the polymer science behind thermoplastic and reactive hot melt systems

Hot Melt Adhesive Chemistry Overview

Hot melt adhesives (HMAs) are 100% solid systems applied in the molten state that form bonds upon cooling, eliminating the solvents, cure times, and material waste associated with liquid adhesives. The performance characteristics of any hot melt are determined almost entirely by its polymer backbone, which governs open time, set speed, temperature resistance, flexibility, and substrate compatibility.

The hot melt category divides into two fundamentally different system types: traditional thermoplastic HMAs, which rely on reversible physical phase changes, and polyurethane reactive (PUR) hot melts, which undergo an irreversible moisture-cure crosslinking reaction after application. Selecting between these systems, and between chemistries within each group, is a materials engineering decision with direct consequences for end-product durability, process throughput, and cost.

This page maps the primary hot melt chemistries to their polymer engineering rationale, explains the curing kinetics that differentiate thermoplastic from reactive systems, and guides selection by industry application.

Traditional Thermoplastic HMAs

Strength develops through a physical phase change as polymer chains re-entangle during cooling. Full bond strength is achieved once the adhesive returns to ambient temperature. Because the bond remains thermoplastic, reheating above its softening point allows it to remelt and be reworked.

Chemistries

EVA • mPO • APAO • SBC • Polyamide

Polyurethane Reactive (PUR) Hot Melts

PUR adhesives cure through a two-stage mechanism. Cooling provides immediate green strength for handling, while ambient moisture gradually initiates irreversible crosslinking over 24–72 hours. Once fully cured, the adhesive becomes a thermoset and cannot be remelted.

Chemistry

PUR (Reactive Isocyanate Prepolymer)

 

Traditional Thermoplastic Hot Melt Adhesives

Physical phase-change bonding: four primary polymer chemistries, each engineered for distinct performance requirements

Thermoplastic HMAs solidify by cooling below their glass transition temperature (Tg) or through crystallization. The bond achieves 100% of its final strength the moment it cools to ambient temperature. Because no chemical reaction occurs, the bond remains reversible if reheated above the polymer's softening point. Chemistry selection within this group is driven by required open time, substrate polarity, temperature resistance, and processing method.

EVA Hot Melt Adhesive
Thermoplastic
EVA

Ethylene Vinyl Acetate (EVA)

The foundational chemistry of the packaging and woodworking industries. EVA performance is governed by the ratio of vinyl acetate (VA) to ethylene content. Higher VA content increases chain polarity and flexibility, improving adhesion to polar substrates and reducing set temperature. Higher ethylene content produces a more crystalline structure with faster set times and higher cohesive strength, at the cost of adhesion range.

EVA remains the cost-performance standard for high-volume general industrial bonding where temperature resistance above 80-90°C is not required.

EVA – Key Characteristics
VA Ratio Controls Performance

Higher VA means more flexible, broader adhesion. Higher ethylene means faster set, stronger crystalline cohesion. The ratio is the primary formulation lever.

Cost-Efficient Standard

Lowest raw material cost in the HMA range. Suitable for high-volume applications where temperature resistance requirements do not exceed approximately 80°C service.

Wide Process Compatibility

Compatible with slot die, bead dispensing, and spray application. Available in stick, pellet, and block formats across a wide viscosity range.

 
Thermoplastic
mPO

Metallocene Polyolefins (mPO)

Metallocene catalysis produces polyolefins with a uniquely narrow molecular weight distribution (MWD), a degree of polymer architecture control unavailable with conventional Ziegler-Natta catalysts. This narrow MWD creates a very sharp phase transition: mPO goes from a low-viscosity melt to a high-strength crystalline solid almost instantaneously upon cooling, giving sub-second green strength in high-speed automated lines.

The narrow MWD also yields superior thermal stability with significantly reduced charring and char deposits in applicator systems, a major operational advantage in continuous-run production. mPO adhesives have largely displaced EVA in demanding high-speed packaging and product assembly applications.

Metallocene Polyolefin mPO Hot Melt

mPO vs EVA – Key Differences

Property mPO EVA
Set Speed Very fast (sub-second possible) Moderate to fast
Thermal Stability Superior; minimal charring Moderate; char buildup over time
Temperature Resistance Higher service temperature range Limited (typically below 80°C)
Cost Higher raw material cost Lowest cost baseline
 
APAO Amorphous Poly-Alpha-Olefin Hot Melt
Thermoplastic
APAO

Amorphous Poly-Alpha-Olefins (APAO)

APAOs are synthesized using traditional Ziegler-Natta multi-site catalysts, which produce polymers with a broad molecular weight distribution and an amorphous (non-crystalline) microstructure. This amorphous nature is the defining performance characteristic: where mPO crystallizes sharply upon cooling, APAO cools gradually through a wide softening range.

This extended softening range translates directly into extended open time, a critical requirement for applications where the adhesive must remain tacky after dispensing, spanning the distance from nozzle to substrate in spray applications, or wetting out large, irregular surfaces before bonding occurs.

APAOs also provide excellent adhesion to low-surface-energy (LSE) plastics and exceptional low-temperature flexibility, properties that make them the preferred chemistry for hygiene product manufacturing, mattress assembly, and automotive acoustic insulation where broad-area spray dispensing is the process method.

Specialty Thermoplastic Chemistries
Styrenic Block Copolymer illustration
 
Thermoplastic SBC

Styrenic Block Copolymers (SBC)

SBCs possess a unique phase-separated morphology of hard polystyrene domains and soft rubbery midblocks. This microstructure delivers a combination no other thermoplastic HMA achieves: the fast hot-melt processability of standard systems alongside continuous room-temperature flexibility, high initial tack, and rubber-like elasticity.

SBCs are the chemistry of choice for hot melt pressure-sensitive adhesives (HMPSAs), applications requiring permanent room-temperature tack, such as self-adhesive strips in hygiene products, label adhesives, and repositionable mounting tapes.

Primary Use: Hot Melt Pressure-Sensitive Adhesives (HMPSAs), hygiene products, self-adhesive strips, label adhesives

Polyamide Hot Melt
 
Thermoplastic Polyamide

Polyamide (PA)

Derived from the condensation reaction of dimerized fatty acids and diamines, polyamide hot melts are highly crystalline polymers with sharp melting points. This crystallinity yields the highest temperature resistance and creep resistance of any thermoplastic HMA, making PA the preferred option for demanding automotive underhood and industrial environments.

PA adhesives also possess excellent dielectric properties and exceptional resistance to plasticizer migration, critical when bonding PVC or untreated polyethylene in chemically aggressive environments. Their low melt viscosity also enables low-pressure molding for electronic encapsulation.

Primary Use: Low-Pressure Molding (LPM) for PCB encapsulation, high-temperature bonding, and PVC/PE adhesion in harsh environments.

Thermoplastic HMA – Key Benefits & Drawbacks Summary

 

hot melt adhesives

 

Curing Kinetics – Thermoplastic vs Reactive Systems

The most critical factor in process engineering is understanding how and when bond strength develops

Thermoplastic Cure (EVA, mPO, PA)

Physical Phase Change

Strength development is purely thermodynamic. As heat dissipates into the substrates and surrounding air, polymer chains re-entangle and the adhesive solidifies. The bond achieves its full design strength immediately after cooling to ambient temperature.

If reheated above the softening point, the adhesive reliquefies and the bond loses strength. This reversibility provides excellent reworkability but also defines the maximum service temperature of the assembly.

Thermoplastic HMA Curing Kinetics Diagram
Reactive Moisture Cure (PUR)

Two-Stage Cure Kinetics

Physical Stage: The prepolymer cools and solidifies, rapidly developing green strength. Assemblies can be handled, machined, or packaged immediately without clamping, improving manufacturing throughput.

Chemical Stage: Residual isocyanate (NCO) groups react with ambient moisture over 24–72 hours, forming stable urea linkages and a permanently crosslinked network. Once cured, PUR behaves as an elastomeric thermoset and can no longer be remelted.

PUR Reactive Hot Melt Two-Stage Cure Diagram
 

Polyurethane Reactive Hot Melts (PUR)

Bridging hot melt processing speed with structural adhesive performance, for applications where thermoplastic bonds fail under thermal or chemical stress

PUR adhesives occupy a unique position in the bonding landscape: they are solid at room temperature (enabling hot melt processing), but contain low-molecular-weight prepolymers with residual, unreacted isocyanate (NCO) groups that enable a post-application crosslinking reaction.

PURs are heated to a molten state (typically 110-130°C) and dispensed onto the substrate. As they cool, polymer chains rapidly crystallize, providing immediate green strength within seconds to minutes, allowing immediate handling without clamping. This distinguishes PUR from two-part reactive adhesives that require fixture time.

The secondary, slower chemical reaction then begins: NCO groups react with ambient moisture over 24-72 hours to form a permanently crosslinked thermoset network. Because of this secondary crosslinking, fully cured PUR adhesives cannot be remelted, and they exhibit extraordinary thermal resistance, solvent resistance, and creep resistance compared to any thermoplastic hot melt adhesive.

Key Process Note: PUR requires moisture-controlled storage and application conditions. Open cartridges or tanks must be protected from ambient humidity exposure prior to application, as premature NCO reaction reduces working viscosity and crosslink density.

PUR vs Thermoplastic HMA – Performance Comparison
Thermoset After Cure

Once moisture-cured, PUR cannot be remelted. Service temperature ceiling is determined by the crosslink network, not a softening point, enabling use in paint-bake cycles and high-heat environments impossible for EVA or mPO.

Immediate Green Strength

Physical crystallization on cooling delivers handling strength within seconds, no fixture time, no clamping required. Production throughput advantages match or exceed standard thermoplastic HMA systems.

Chemical & Creep Resistance

Crosslinked urea network provides resistance to solvents, fuels, cleaning agents, and sustained static loads that would cause thermoplastic bonds to creep or fail over time.

 

Applications & Polymer Selection by Industry

The engineering rationale for chemistry selection in each major application segment

Automotive Hot Melt Adhesive Application
Recommended Reactive PUR

Automotive & Transportation

Automotive cabins experience severe and sustained thermal cycling, from sub-zero overnight temperatures to elevated in-cabin heat on summer days. Conventional thermoplastic hot melts such as EVA and mPO gradually soften under prolonged heat and static shear loading, making them susceptible to creep. Moisture-cured PUR adhesives form an irreversible thermoset elastomer that maintains structural integrity throughout these demanding operating conditions.

PUR has therefore become the preferred chemistry for automotive headliner bonding, interior trim attachment, seating foam assembly, acoustic insulation lamination, and other applications requiring long-term heat resistance, vibration damping, and durable structural performance.

 
Recommended Polyamide (PA) for LPM / PUR for Micro-Bonding

Electronics – Low-Pressure Molding & PCB Encapsulation

Low-Pressure Molding (LPM uses polyamide (PA) hot melts for PCB encapsulation, sensor potting, and watertight connector overmolding. PA exhibits exceptionally low melt viscosity, enabling injection into aluminum mold cavities at ultra-low pressures (1.5–40 bar). The adhesive crystallizes within seconds, simultaneously functioning as both the protective encapsulant and the external housing while providing a watertight (IP67), flame-retardant (UL94 V-0) enclosure without high-pressure tooling.

For micro-bonding and sealing of consumer electronics, including OLED displays, flexible circuits, and camera modules, PUR is the preferred chemistry. Its relatively low application temperature (100–110°C) minimizes thermal distortion of thin plastic housings and protects heat-sensitive components. After curing, the elastomeric network absorbs vibration and impact while still permitting localized thermal rework, improving manufacturing yield and component recovery.

Electronics PCB LPM Encapsulation Hot Melt
 
Structural Woodworking and Edge Banding
Primary PUR Secondary Filled EVA

Structural Woodworking & Edge Banding

In environments exposed to moisture, elevated temperatures, and repeated cleaning cycles, such as kitchen cabinetry, bathroom vanities, and exterior furniture, the adhesive bond must resist steam, water ingress, and long-term environmental aging. Moisture-cured PUR adhesives form a permanently crosslinked thermoset network that penetrates and mechanically interlocks with the porous cellular structure of wood and engineered particleboard, delivering exceptional water resistance and virtually invisible edge-banding bond lines.

For interior furniture and other applications where moisture exposure is minimal, highly filled EVA hot melts containing calcium carbonate (CaCO₃) offer a cost-effective alternative. These formulations provide reliable adhesion, improved gap-filling capability, and efficient processing on porous wood-based substrates while maintaining excellent production throughput.

 
Textiles, Non-Wovens and Hygiene Hot Melt Adhesives
 
APAO + SBC

Textiles, Non-Wovens & Hygiene

Wide-web spray dispensing used in mattress manufacturing, hygiene products, and acoustic insulation requires adhesives with sufficient open time to bridge the distance from the spray nozzle to the substrate without premature cooling. APAO's fully amorphous molecular structure provides this extended processing window. For self-adhesive fastening strips used in hygiene products, SBC-based hot melt pressure-sensitive adhesives deliver permanent room-temperature tack and excellent long-term flexibility.

High-Speed Packaging Hot Melt Adhesives
 
mPO + EVA

High-Speed End-of-Line Packaging

Modern automated packaging lines demand adhesives capable of achieving full green strength within fractions of a second. Metallocene polyolefin (mPO) hot melts dominate these high-speed operations because their narrow molecular weight distribution produces rapid crystallization and minimizes stringing during application. For lower-speed or cost-sensitive packaging and case-sealing applications, EVA remains the industry standard due to its reliable performance, broad substrate compatibility, and economical processing.

 
Application Recommended Chemistry Rationale
High-speed packaging / case sealing mPO (preferred), EVA (legacy/cost) Sub-second set, thermal stability, no stringing
Automotive interior bonding PUR Thermoset after cure, thermal cycling resistance, no creep
PCB encapsulation / LPM Polyamide (PA) Low injection pressure, fast crystallization, IP67 / UL94 V-0
Electronics micro-bonding & sealing PUR (low-temp) Low application temp, shock absorption, reworkable with heat
Edge banding (moisture-exposed) PUR Water resistance, invisible bond line, locks into wood cell structure
Edge banding (interior, dry) Filled EVA Cost-effective, gap filling in particleboard
Mattress / foam spray laminating APAO Extended open time, LSE adhesion, wide-web sprayability
Hygiene product PSA strips SBC (HMPSA) Permanent room-temperature tack, elasticity
High-temp industrial / LSE plastic bonding Polyamide (PA) Highest temp resistance, dielectric properties, plasticizer migration resistance
 

Need Help Selecting the Right Hot Melt System?

Chemistry selection in hot melt adhesives depends on your substrate combination, required open time, service temperature, and production process. Our technical team provides product selection support, trial quantity sourcing, and application guidance across EVA, mPO, APAO, SBC, polyamide, and PUR systems.

Hot Melt Chemistry – Quick Reference

EVAGeneral purpose, cost baseline, packaging
mPOHigh-speed, thermal stability, no stringing
APAOExtended open time, LSE adhesion, spray
SBCPressure-sensitive tack, flexibility, HMPSAs
PolyamideLPM, high-temp, dielectric, LSE plastics
PURThermoset after cure, automotive, woodworking

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