High-temperature silicone is a specialized elastomeric material engineered to withstand extreme thermal conditions while retaining critical properties like elasticity, stabilité chimique, and insulation. Unlike standard silicone (which typically maxes out at 150°C), it thrives in environments ranging from -60°C to 300°C (with some grades handling short bursts of 350°C+), making it indispensable for industrial sealing, fabrication de moules, and electronic protection. Cet article détaille ses principales caractéristiques, classifications, scénarios d'application, and step-by-step usage guidelines—with clear comparisons and practical tips to help you select and apply it correctly.
1. Core Characteristics of High-Temperature Silicone
High-temperature silicone’s value stems from a unique combination of thermal and mechanical properties that outperform standard silicone and other elastomers. Below are its non-negotiable traits, backed by actionable data:
| Caractéristiques | Indicateurs de performance clés | Exemple d'impact dans le monde réel |
| Exceptional Thermal Resistance | – Continuous use range: -60°C to 300°C.- Short-term peak resistance: 350° C (special grades).- Maintient 80% of elasticity after 1,000 hours at 250°C. | An automotive engine gasket made from high-temperature silicone remains flexible and leak-free, Même après 500+ hours of exposure to 220°C exhaust heat—unlike standard silicone, which hardens and cracks after 100 heures. |
| Météo & Durabilité environnementale | – Resists UV degradation (no brittleness after 2,000 hours of sunlight).- Withstands ozone, humidité, and salt spray (passes 500-hour salt fog tests). | A high-temperature silicone seal for outdoor industrial ovens shows no signs of cracking or discoloration after 1 year of exposure to rain, Rayons UV, et les fluctuations de la température (-10°C to 280°C). |
| Stabilité chimique | – Resists corrosion from weak acids (pH 4–10), alcalis, huiles minérales, Et la plupart des solvants (Par exemple, éthanol, acétone).- Compliant with FDA 21 CFR 177.2600 (food-grade variants). | A food-grade high-temperature silicone baking mold safely endures repeated exposure to 220°C oven heat and cleaning with harsh dish soap—no chemical leaching or material degradation. |
| Isolation électrique | – Résistivité du volume: ≥10¹⁴ Ω·cm (at 250°C).- Dielectric strength: ≥20 kV/mm (prevents electrical arcing). | High-temperature silicone potting compound protects LED driver modules in industrial lighting, maintaining insulation integrity even when the module reaches 180°C during operation. |
| Mechanical Flexibility | – Rivage une dureté: 20–60 (réglable pour des besoins spécifiques).- Allongement à la pause: ≥300% (handles thermal expansion/contraction). | A high-temperature silicone O-ring for a boiler pipe expands and contracts with temperature changes (100°C to 280°C) without leaking—its flexibility prevents stress cracks. |
2. Classification of High-Temperature Silicone
High-temperature silicone is categorized by two key factors: curing mechanism (how it hardens) and end-use (what it’s designed to do). Understanding these categories ensures you select the right grade for your project.
2.1 By Curing Mechanism
| Taper | Agent de durcissement & Processus | Avantages clés | Désavantage | Idéal pour |
| Additif (Platinum-Cure) Silicone à haute température | Cured with platinum catalysts; no byproducts released during curing. | – Respectueux de l'environnement (inodore, no toxic emissions).- Faible retrait (0.1–0,5%)—critical for precision molds.- Excellente transparence (for optical applications). | – Coût plus élevé (20–30% more than condensation types).- Sensitive to contamination (Par exemple, sulfur ruins curing). | Moules de précision (Par exemple, semiconductor component molds), food-grade applications (moules à cuisson), and optical parts (light diffusers). |
| Condensation High-Temperature Silicone | Cured with tin catalysts; releases small byproducts (Par exemple, éthanol, acide acétique) Pendant le durcissement. | – Coût inférieur (budget-friendly for large-volume use).- Less sensitive to contamination.- Faster room-temperature curing (12–24 hours vs. 24–48 hours for additive). | – Mild odor (fades after curing).- Retrait plus élevé (1–2%)—not for precision parts.- Byproducts may corrode sensitive metals (Par exemple, cuivre). | General industrial sealing (joints de tuyaux), non-precision molds (rubber vulcanization molds), and low-cost repair projects (metal crack sealing). |
2.2 By End-Use
| Taper | Formulaire & Propriétés clés | Exemples d'application |
| High-Temperature Sealant | Paste or liquid form; cures to a flexible elastomer. | – Boiler pipe joints (prevents high-temperature gas leakage).- Ovens and furnaces (joints de porte, heating element gaskets).- Automotive exhaust systems (manifold gaskets). |
| High-Temperature Mold Adhesive | Flowable liquid; designed to capture fine details in molds. | – Die-casting molds (for metal alloys like aluminum).- Rubber vulcanization molds (for automotive hoses).- Food-grade baking molds (cake pans, moules à chocolat). |
| High-Temperature Electronic Potting Compound | Viscous liquid; cures to a rigid or flexible solid (réglable). | – Potting LED drivers, transformateurs, and power modules (protects from heat and moisture).- Encapsulating sensors in industrial machinery (withstands 250°C+). |
| High-Temperature Sheet Silicone | Pre-cured sheets (0.5–10 mm d'épaisseur); ready to cut and use. | – Gaskets for industrial ovens and fryers.- Insulation pads for electronic components (Par exemple, CPU heat sinks).- Seals for aerospace ducting (withstands 300°C). |
3. Scénarios d'application clés
High-temperature silicone’s versatility makes it a staple across industries where heat, produits chimiques, or environmental stress are constant challenges.
| Industrie | Specific Use Cases | Why High-Temperature Silicone Is Irreplaceable |
| Fabrication industrielle | – Boiler/furnace seals and gaskets.- Die-casting molds for metal parts.- Potting for industrial sensors (Par exemple, temperature probes). | Withstands continuous exposure to 250°C–300°C; resists corrosion from industrial oils and cleaning solvents. |
| Automobile & Aérospatial | – Engine gaskets (casseroles à pétrole, collecteurs d'échappement).- Aerospace ducting seals (300° C +).- Battery pack insulation (véhicules électriques). | Handles thermal cycling (from -40°C to 280°C) Sans dégradation; léger (reduces vehicle/aerospace weight). |
| Nourriture & Boisson | – Moules à cuisson (cookies, bread).- Food processing equipment seals (Par exemple, Convoyeur).- Microwave-safe cookware liners. | Conforme à la FDA (Aucune lixiviation chimique); withstands 220°C–250°C oven/microwave heat. |
| Électronique | – LED driver potting (high-power LEDs).- Transformer insulation.- Circuit board conformal coating (protects from heat/moisture). | Maintains electrical insulation at 180°C+; prevents short circuits from thermal expansion. |
| Maison & Bricolage | – High-temperature repair (metal pipe cracks, ceramic tile fixes).- Grill/searing pan gaskets.- Homemade candle molds (heat-resistant to wax melting). | Easy to apply (room-temperature curing); no specialized tools needed for small projects. |
4. Step-by-Step Guide to Using High-Temperature Silicone
Proper application ensures high-temperature silicone performs as intended. Follow this workflow for sealing, fabrication de moisissures, or potting:
4.1 Préparation (Critique pour le succès)
- Nettoyage de surface:
- Wipe the target surface (Par exemple, pipe joint, châssis de moule) avec de l'alcool isopropylique (70–90%) Pour enlever l'huile, poussière, or rust. For metal surfaces, use a wire brush to remove corrosion—contaminants prevent adhesion.
- Outil & Préparation du matériel:
- Rassembler des outils: electronic scale (±0.1g), stir rod (glass/plastic), agent de démoulage (petroleum jelly for molds), and a vacuum degassing machine (for precision applications).
- Verify the silicone grade: Ensure it matches your temperature needs (Par exemple, 300°C for oven seals) and compliance requirements (Par exemple, FDA for food use).
4.2 Mélange (Avoid Curing Failures)
- Ratio Accuracy:
- Follow the manufacturer’s ratio (Par exemple, 10:1 for condensation silicone, 1:1 for additive silicone). Use an electronic scale—even a 1% error (Par exemple, 100:4 au lieu de 100:5) causes incomplete curing.
- Bubble Removal:
- Stir slowly in one direction (2–3 minutes) to avoid trapping air. For molds or potting, use a vacuum degassing machine (-0.1MPA) for 1–2 minutes—bubbles in the silicone cause leaks or voids.
4.3 Application (Tailor to End-Use)
| Cas d'utilisation | Application Steps | Conseils pour réussir |
| Scellage (Pipes/Ovens) | 1. Apply silicone in a continuous bead along the gap (3–5mm thick).2. Use a spatula to smooth the bead and ensure full contact.3. Let cure per instructions. | – Avoid over-applying (wastes material).- For vertical surfaces, apply from bottom to top to prevent sagging. |
| Fabrication de moisissures | 1. Apply release agent to the prototype (Par exemple, petroleum jelly for wax models).2. Pour silicone over the prototype (tilt the mold frame to reduce bubbles).3. Cure fully before demolding. | – Pour des prototypes complexes, use a split mold design (avoids tearing).- Extend curing time by 50% for thick molds (>10MM). |
| Electronic Potting | 1. Place the component (Par exemple, LED driver) in a potting box.2. Pour silicone to fully cover the component (1–2mm extra for protection).3. Cure at room temperature or accelerate with heat. | – Use a low-viscosity grade (flows into small component gaps).- Avoid trapping air around sensitive parts (Par exemple, condensateurs). |
4.4 Durcissement & Post-traitement
- Conditions de durcissement:
- Durcissement à température ambiante: 24–48 heures (condensation silicone: 12–24 heures; additive silicone: 24–48 heures).
- Durcissement accéléré: Heat at 60–100°C (reduces time by 50%, Par exemple, 24 heures → 12 heures). Do not exceed 120°C (may cause brittleness).
- Post-traitement:
- Après guérison, trim excess silicone with a sharp knife. For food-grade applications, wash the surface with warm soapy water and air-dry (removes any residual curing agents).
5. Critical Precautions to Avoid Failures
Even high-quality high-temperature silicone fails if misused. Suivez ces règles:
- Contrôle de la contamination:
- Additif (platinum-cure) silicone is sensitive to sulfur, étain, and certain oils (Par exemple, motor oil)—keep it away from rubber gloves, lubrifiants, or sulfur-containing materials (ruins curing).
- For condensation silicone, avoid contact with copper or brass (byproducts cause corrosion).
- Temperature Limits:
- Do not exceed the silicone’s continuous use temperature (Par exemple, a 300°C grade should not be used long-term at 350°C). Short bursts of peak temperature are safe only if specified by the manufacturer.
- Stockage:
- Unopened silicone: Conserver au frais, lieu sec (15°C–25°C) Loin de la lumière directe du soleil. Durée de conservation: 6–12 mois (additive silicone); 12–24 mois (condensation silicone).
- Opened silicone: Seal tightly after use—moisture absorption degrades performance.
- Sécurité:
- Travailler dans une zone bien ventilée (condensation silicone releases mild fumes during curing).
- Wear nitrile gloves and safety goggles (uncured silicone may irritate skin/eyes).
6. Yigu Technology’s Perspective on High-Temperature Silicone
À la technologie Yigu, we’ve seen high-temperature silicone solve critical challenges for clients—from automotive manufacturers to food processors. A common mistake we address is choosing the wrong curing type: one client used condensation silicone for a precision semiconductor mold, résultant en 2% rétrécissement (ruining part fit). We switched them to additive silicone (0.3% rétrécissement), which fixed the issue and reduced rework costs by 40%. Pour les projets de qualité alimentaire, we always recommend platinum-cure variants (Conforme à la FDA, pas d'odeur) over condensation types. We also emphasize vacuum degassing for mold applications—this eliminates 95% of bubbles that cause leaks in high-temperature seals. High-temperature silicone isn’t just a material—it’s a reliability tool; selecting the right grade and following proper application steps ensures long-term performance, even in extreme environments.
7. FAQ: Common Questions About High-Temperature Silicone
T1: Will high-temperature silicone harden or become brittle in cold environments (Par exemple, -60° C)?
A1: High-temperature silicone retains flexibility down to -60°C—unlike standard rubber, which becomes brittle below 0°C. It may feel slightly stiffer in cold temperatures but returns to full elasticity when warmed to room temperature. Par exemple, a high-temperature silicone O-ring for a freezer-to-oven conveyor belt remains functional at -40°C and 280°C without cracking.
T2: Can I paint or bond high-temperature silicone to other materials (Par exemple, métal, plastique)?
A2: Oui, but use compatible products:
- Peinture: Use silicone-specific high-temperature paints (Par exemple, silicone-based enamel) that withstand 300°C+—standard paints peel or burn.
- Liaison: Use silicone adhesives (not epoxy or super glue, which don’t adhere to silicone). For metal bonding, choose a high-temperature silicone adhesive with a peel strength of ≥5 N/cm.
T3: How do I verify if a high-temperature silicone is food-safe for baking molds?
A3: Check for two key certifications:
- FDA 21 CFR 177.2600: Ensures no harmful chemicals leach into food.
- LFGB (UE): For European markets—confirms compliance with food contact regulations.
Always ask the manufacturer for a certificate of compliance; avoid using non-certified silicone (even if labeled “high-temperature”) for food applications.