Heat-resistant adhesive Archives

High Tg Epoxy Adhesive: A Practical Guide

The glass transition temperature, Tg, is where an epoxy shifts from a hard, glassy solid to a soft, rubbery one. Above it, stiffness and shear strength drop sharply. A high Tg epoxy adhesive keeps that transition well above the service temperature, which is why it holds a bond that a standard epoxy would lose. What Tg Actually Means for a Bond Below Tg, an epoxy carries load with its full room-temperature strength. As it approaches Tg, modulus falls, creep increases, and a bond under sustained load begins to move. Cross the Tg and the adhesive still holds parts together but no longer performs structurally. The practical rule: keep the maximum continuous service temperature at least 20 to 30 degrees Celsius below the cured adhesive's Tg. If a part runs at 150 degrees, target a Tg of 175 degrees or higher. Where High Tg Epoxies Are Used Aerospace: bonding structure and components near engines and in high-altitude thermal cycling. Automotive: securing parts in engine bays and near exhaust and braking heat. Electronics: attaching heat sinks, bonding substrates, and staking components that run hot. Industrial manufacturing: joining metals, ceramics, and composites in processes that involve elevated temperature. Cure Determines Tg This is the point most often missed: a high Tg epoxy only reaches its rated Tg if it is cured correctly. Most high Tg systems need an elevated-temperature cure or a post-cure ramp. Cure it at room temperature only and the actual Tg lands far below the datasheet value, and the bond fails at a temperature it should have survived. Verify cure by measuring Tg on a sample with a simple thermal method, or at minimum by holding a bonded coupon at the service temperature under load and confirming it does not move. For help building a cure schedule your process can deliver, Email Us. Tradeoffs to Plan For Cure effort. Elevated-temperature or post-cure steps add process time and equipment. Brittleness. High Tg systems are often more rigid at room temperature, so they tolerate less peel and impact. A toughened high Tg grade recovers some of that. Thermal stress. A rigid bond between materials with different expansion rates concentrates stress at the interface, the mechanism in how CTE mismatch causes adhesive bond failure. Bondline thickness and joint design have to account for it. Selecting a Grade Define these before choosing: Maximum continuous service temperature and any short excursions. Sustained load and whether creep resistance is critical. Peel and impact demands at room temperature. Substrates and their surface condition. The cure schedule the production line can support. Incure's Epo-Weld epoxy range includes high-temperature structural grades formulated for elevated Tg. When the choice is between chemistries for a demanding structural joint, the comparison in UV glue versus epoxy for heavy-duty repairs covers the strength tradeoffs. Wet Tg and Real Service Datasheets quote a dry Tg measured on a freshly cured sample. In humid service, epoxies absorb 1 to 3 percent water by weight, and that absorbed moisture plasticizes the polymer and drops the effective…

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November 27, 2024

Electronics Adhesives

Potting Compounds for Extreme Environments: Incure Uni-Seal 6213HT

Electronics that run hot, sit outdoors, or live inside a machine face a punishing mix of heat, moisture, vibration, and chemicals. A potting compound that passes a bench test can still crack or absorb water after a season in the field. Incure Uni-Seal 6213HT is built for assemblies that must keep working under those conditions. What Potting Does Potting fills the cavity around a circuit or component with a solid resin, creating a continuous barrier against the environment and a mechanical anchor against shock and vibration. Unlike a thin conformal coating, a potted section is fully encased, which raises protection but also puts the resin in intimate contact with every component. That makes two properties critical: low stress on the parts and stable behavior across temperature. Where Uni-Seal 6213HT Fits Uni-Seal 6213HT is a thick-viscosity adhesive that cures under UV, visible, or LED light, with heat as a secondary path for shadowed regions. The high viscosity keeps it in place on vertical walls and around tall components during application, and the multi-mode cure lets it set fully even where light cannot reach every surface. Key characteristics for demanding service: Deep single-pass potting to roughly 5 mm, forming a hard solid pot without repeated lifts Chemical resistance to mineral oils, fuels, gases, and common industrial solvents Low water absorption and low shrinkage, which limits dimensional change and internal stress over the service life Adhesion to metals, glass, and ceramics, so the pot stays bonded to the housing and substrate Smooth cured finish suitable for inspection and downstream handling Selecting and Applying a Potting Compound Match the resin to the environment. For high-temperature or chemically aggressive service, prioritize a low coefficient of thermal expansion, a glass transition temperature above the maximum operating temperature, and demonstrated resistance to the specific fluids present. For assemblies that dissipate significant heat, a thermally conductive grade moves that heat into the housing instead of trapping it. Process control determines whether those properties actually reach the finished part: Prepare surfaces. Clean off flux residue, oils, and mold release so the resin can wet and bond the substrate. Manage the exotherm. In deep or large-volume pots, cure in controlled steps so reaction heat does not spike and generate voids or shrinkage stress. Remove entrapped air. Vacuum degassing before or during pour prevents bubbles that concentrate stress and reduce dielectric performance. Cure completely. Confirm shadowed regions receive the secondary heat cycle, and verify hardness against the datasheet before releasing parts. Because the resin and the components expand at different rates, thermal cycling is where marginal potting jobs fail. Reviewing how expansion mismatch drives cracking and delamination helps explain why a compliant, low-shrinkage resin outlasts a harder, higher-stress one in cycling service. UV and visible-light potting resins also depend on adequate cure energy, so pairing the material with the right LED flood lamp for the curing area is part of the specification. For help evaluating Uni-Seal 6213HT against your temperature, chemical, and mechanical requirements, Email Us with your operating conditions. Thermal…

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August 21, 2024

Cyanoacrylate

Black Heat-Resistant Glue: Incure Heat-Resist™ 320

When a bond line will be visible on a finished product and the assembly runs hot, a clear adhesive that yellows or blooms is a cosmetic liability. Black heat-resistant glue solves both problems at once, and Incure Heat-Resist™ 320 pairs a pigmented finish with genuine elevated-temperature performance. Why Color Matters at the Bond Line Standard cyanoacrylate cures clear but is prone to frosting, or blooming, as monomer vapor settles on nearby surfaces and reacts with ambient moisture. On a dark housing or a machined casting, that white haze stands out. A black-pigmented grade hides the joint, masks minor squeeze-out, and gives line operators and inspectors an immediate visual cue that adhesive is present and correctly placed. Heat-Resist™ 320 is a single-component, medium-viscosity cyanoacrylate that cures to an opaque black film. It carries the same modified chemistry as the rest of the Heat-Resist™ line, so the color is not a trade-off against thermal capability. Incure Heat-Resist™ 320 at a Glance Chemistry: single-component, room-temperature-cure cyanoacrylate, black Viscosity: medium, for controlled placement and small gap filling Fixture speed: seconds to tens of seconds depending on substrate and humidity Bond strength: up to roughly 5,200 psi on suitable rigid plastics Thermal behavior: engineered for thermal-shock resistance and elevated continuous service Chemical resistance: withstands alcohols, aliphatic fuels, aromatic hydrocarbons, and dilute acids and bases Substrates and Joint Design Heat-Resist™ 320 bonds most engineering thermoplastics, elastomers, cured composites, and prepared metals. Keep the bond line thin, between 0.05 and 0.15 mm, and load the joint in shear. Because the film is rigid, add a mechanical feature to carry peak load on any joint that flexes in service. Prime low-surface-energy plastics such as polyolefins before bonding. The opaque film also blocks light, which matters when a joint sits next to an optical path or a sensor window. For assemblies that mix rigid and flexible plastics with a wide temperature range, read how CTE mismatch causes adhesive bond failure so differential expansion does not overload the joint. Application and Cure Control Wipe both faces with isopropyl alcohol and let them dry. Dispense one thin drop or bead on a single face; over-application cures slowly and can still bloom despite the pigment. Mate within the open time, hold light fixture pressure, and allow 24 hours for full strength and peak heat resistance. A brief 80–100°C post-cure speeds the climb to full properties on a production line. Hold shop humidity between 40 and 60 percent for repeatable fixture times. Use an activator on inactive surfaces or where the gap exceeds what the adhesive bridges alone. On automated equipment, meter each shot so the cured film thickness stays consistent part to part. For a broader view of how cure speed and working time trade off, see which adhesive dries faster for quick repairs. Where Heat-Resist™ 320 Fits Consumer electronics: visible seams on dark enclosures that sit near warm power components Automotive: trim, clips, and sensor mounts in the engine bay where appearance and heat both matter Industrial equipment: machinery housings and…

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August 15, 2024

Cyanoacrylate

High Temperature Super Glue: Incure Heat-Resist™ 311

Standard cyanoacrylate is fast and convenient, but it starts to lose strength above about 80°C and degrades quickly with humidity and temperature cycling. Incure Heat-Resist™ 311 is a cyanoacrylate reformulated to hold up where ordinary instant adhesives fail. What Heat-Resist™ 311 is Heat-Resist™ 311 is a single-component, high-viscosity cyanoacrylate designed for thermal resistance and gap filling. It cures in seconds through contact with surface moisture, needs no mixing or heat, and reaches high strength quickly, achieving up to about 5,200 psi on some plastics. The higher viscosity lets it bridge small gaps and hold on vertical surfaces without running, which thin cyanoacrylates cannot do. The cured adhesive tolerates elevated temperatures and temperature cycling better than a general-purpose instant adhesive, and it resists common solvents including alcohol, petrol, and dilute acids and bases. Key properties and what they mean Thermal resistance. The formulation holds a larger share of its strength at elevated temperature and after thermal cycling, extending cyanoacrylate into applications that would normally require an epoxy. High viscosity. Gap filling up to a few tenths of a millimeter and no-run behavior on vertical joints, at the cost of slower wicking into tight assemblies. Fast fixture. Parts reach handling strength in seconds, so no clamping or fixturing time is needed for small joints. Chemical resistance. The bond survives incidental exposure to fuels, solvents, and cleaning chemistry. Where Heat-Resist™ 311 fits Automotive and aerospace: tacking and bonding small components, trim, and wire management hardware in warm locations. Industrial equipment and machinery: fast bonding of gaskets, pads, magnets, and small brackets near heat sources. Electronics assembly: securing components, strain-relieving wires, and bonding small parts that see operating heat. Consumer electronics and appliances: joining plastic and elastomer parts in devices that run warm. General maintenance: quick repairs on equipment where an epoxy cure time is impractical. Working with a fast cyanoacrylate Fit matters more than clamp force. Cyanoacrylate works best in a close-fitting joint. Heat-Resist™ 311's viscosity handles a small gap, but a large gap slows cure and weakens the bond. One-sided application. Apply to one surface only and assemble promptly. Applying to both faces can cause a flash cure before the parts meet. Ventilate. Cyanoacrylate vapor can bloom onto nearby surfaces as a white haze. Good airflow and minimal adhesive reduce it. Humidity drives cure. Very dry conditions slow the set; very humid conditions can make it too fast and reduce strength. Normal shop humidity is ideal. For high-strength structural joints, gap-bonding large areas, or joints that must survive continuous high temperature, an epoxy is usually the better tool. This comparison of which adhesive is stronger for heavy-duty repairs covers where each fits, and which adhesive dries faster for quick repairs covers the speed trade-offs. If you are unsure whether a cyanoacrylate will hold at your service temperature, Email Us with the temperature and the substrates. Surface preparation and substrates Clean both surfaces with a solvent to remove oil and dust and let them dry. Cyanoacrylate bonds most plastics, elastomers, metals, and ceramics…

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August 15, 2024