HCR (Solid Silicone Rubber):
HCR is a high-viscosity, gum-like material that requires mechanical mixing and compression, transfer, or injection molding. It is usually supplied in strips or blocks and must be manually loaded into the mold.
LSR (Liquid Silicone Rubber):
LSR is a two-part liquid system (A+B components) that is automatically mixed and injected into molds using specialized injection machines. It offers higher production automation and consistency.
2. Advantages
| Category | HCR (Solid Silicone Rubber) | LSR (Liquid Silicone Rubber) |
|---|---|---|
| Process Flexibility | Suitable for various molding methods like compression or transfer molding. | Ideal for high-volume automated injection molding with minimal labor. |
| Physical Properties | Excellent mechanical strength and tear resistance. | Excellent transparency, precision, and stable properties for thin-walled parts. |
| Cost | Lower material and equipment cost for small or medium batches. | Higher initial investment but lower per-part cost in mass production. |
| Customization | Easier to mix pigments and additives manually. | Ensures consistent color and quality due to precise mixing system. |
| Applications | Commonly used in keypads, rollers, seals, and gaskets. | Ideal for baby products, medical devices, pet supplies, and high-precision parts. |
| Category | HCR (Solid Silicone Rubber) | LSR (Liquid Silicone Rubber) |
|---|---|---|
| Production Efficiency | Requires manual operation; slower cycle time. | High automation cost and complex equipment setup. |
| Dimensional Accuracy | Less precise compared to LSR due to manual processing. | Limited color options during production; mixing ratio must be exact. |
| Material Handling | Needs careful storage and pre-forming before molding. | Requires accurate metering and temperature control. |
| Cost Suitability | Not ideal for high-volume production. | Higher cost for small-batch or custom colors. |
Solid silicone rubber is widely used in products that require durability, high mechanical strength, and resistance to heat or pressure.
Typical application fields include:
Industrial Components: Seals, gaskets, O-rings, rollers, and insulation sleeves.
Automotive Industry: Spark plug boots, hoses, engine seals, vibration dampers.
Electronics: Keypads, protective covers, insulation parts.
Household Products: Cookware handles, baking mats, and silicone rollers.
Pet Products: Chew toys, slow-feeding mats, and durable pet bowls.
Medical and Healthcare (non-implant): Rubber stoppers, tubing, grips, and device seals.
Liquid silicone rubber is preferred for high-precision, hygienic, and automated manufacturing processes.
Typical application fields include:
Baby Products: Pacifiers, baby bottle nipples, feeding spoons, and teething toys.
Medical Devices: Catheters, respiratory masks, valves, syringe seals, and wearable parts.
Consumer Electronics: Keypads, seals for smartwatches and earbuds, waterproof components.
Kitchenware: Food-grade molds, lids, and reusable storage bags.
Pet Supplies: Lick mats, slow-feeding bowls, and soft pet grooming tools.
Automotive: High-performance seals, grommets, and membrane parts requiring precision.
| Step | HCR (Solid Silicone Rubber) | LSR (Liquid Silicone Rubber) |
|---|---|---|
| Form | Supplied as solid gum-like sheets or blocks. | Supplied as two liquid components (Part A and Part B). |
| Mixing | Pigments and additives are mixed manually or by a two-roll mill. | Automatically metered and mixed in a 1:1 ratio using a dosing system. |
| Handling | Requires manual pre-forming or cutting before molding. | Directly injected into the mold — no pre-forming required. |
| Step | HCR (Solid Silicone Rubber) | LSR (Liquid Silicone Rubber) |
|---|---|---|
| Molding Method | Compression molding, transfer molding, or injection molding. | Liquid injection molding (LIM) process only. |
| Process Type | Semi-automatic, with higher labor involvement. | Fully automatic and computer-controlled. |
| Curing Method | Vulcanized under heat and pressure (typically 160–200°C). | Rapidly cured in the closed mold at 120–180°C. |
| Cycle Time | Longer cycle time (minutes per part). | Shorter cycle time (seconds per part). |
| Step | HCR (Solid Silicone Rubber) | LSR (Liquid Silicone Rubber) |
|---|---|---|
| Demolding | Manual demolding, may require trimming of flash. | Automatic demolding, minimal or no flash. |
| Post-Curing | Often required to remove residual volatiles or improve properties. | Usually unnecessary due to cleaner material chemistry. |
| Finishing | Manual trimming, inspection, and packaging. | Minimal finishing — ideal for automated production lines. |
| Aspect | HCR | LSR |
|---|---|---|
| Automation Level | Low to medium | High |
| Precision | Moderate | Excellent |
| Production Volume | Small to medium batches | High-volume mass production |
| Surface Finish | Matte or textured | Smooth, glossy, and consistent |
| Tooling Cost | Lower | Higher (due to precision molds) |
