In modern facility agriculture, the choice of greenhouse covering material directly determines crop growth cycles, energy consumption, and final yield. Ordinary glass, while transparent, is fragile and expensive. Ordinary plastic film is inexpensive but has a short lifespan and poor insulation. Leveraging over 10 years of experience in polycarbonate sheet development, combined with advanced double-sided UV co-extrusion technology, Innovo Industries has launched the UV-Coated Twin-Wall Polycarbonate Sheet for Greenhouse. This is a high-performance hollow sheet specifically designed for commercial greenhouses, eco-restaurants, and home gardening tunnels. It achieves an excellent balance among four core properties: high light transmission, impact resistance, thermal insulation, and UV resistance, making it one of the ideal covering materials for modern greenhouse construction.
1. Product Positioning: Precise Regulation of Light and Heat for "Efficient Crop Growth"
A greenhouse covering material must simultaneously satisfy two seemingly contradictory requirements: allowing ample sunlight to enter during the day while preventing excessive heat loss, and resisting UV aging during long-term outdoor exposure without excessively filtering out beneficial spectral bands for crops. Innovo's UV-Coated Twin-Wall Polycarbonate Sheet is designed precisely to resolve this contradiction.
The product features a twin-wall hollow structure with internal vertical ribs dividing the sheet into multiple closed air layers. This structure utilizes the low thermal conductivity of air to significantly reduce heat transfer. More importantly, one side (or both sides) of the sheet is co-extruded with a high-concentration UV coating, which effectively blocks excessive ultraviolet radiation that would damage the plastic substrate and cause aging, while retaining the photosynthetically active radiation (PAR) needed by crops. It is a cost-effective, lightweight, safe, and easy-to-install sheet specially designed for greenhouses.
2. Core Technology: UV Co-extruded Coating and Multi-Wall Structure
A. Double-Sided UV Co-extruded Anti-Aging Technology
Ordinary PC sheets will yellow and chalk within about six months of outdoor exposure due to UV attack. Innovo's solution uses a co-extrusion process during sheet production, where a material containing UV absorbers is fused with the PC substrate at the extrusion die, forming a permanent UV protection layer approximately 50 microns thick.
Homogeneous Bonding: The UV layer is chemically bonded to the PC substrate and will not delaminate or peel like sprayed coatings.
Double-Sided Protection: For greenhouse applications, the outer UV layer resists direct sunlight, while the inner UV layer reflects UV rays scattered from the ground and walls, providing full-spectrum protection.
Long Lifespan: Accelerated aging tests confirm that this UV coating ensures the sheet maintains light transmission for over 10 years under normal use, far superior to ordinary uncoated or single-sided coated sheets.
B. Twin-Wall Hollow Structure and Thermal Insulation
The cross-section of this sheet resembles a "sandwich":
Top and Bottom Surfaces: Smooth or slightly textured solid walls with uniform thickness, ensuring even light refraction.
Vertical Ribs: Connect the top and bottom walls, forming regular rectangular air channels.
Thermal Performance: The thermal transmittance (U-value) of the twin-wall structure is significantly lower than that of single-layer materials. For example, an 8mm thick twin-wall PC sheet has a U-value of approximately 3.0 W/m²·K, compared to 4.8 for a 4mm solid PC sheet and about 5.8 for ordinary glass. This means heat inside the greenhouse is lost with greater difficulty, providing significant energy savings in winter.
C. High Light Transmission and Light Quality Regulation
Light Transmission: Clear models can achieve a light transmission rate of over 80% (approaching approximately 90% for glass), sufficient for the photosynthesis needs of most leafy greens and fruiting vegetables. Additionally, the sheet's haze level can be adjusted. Matte or diffusing types convert direct light into diffuse light, eliminating crop shadows and distributing light evenly to the middle and lower leaves of plants.
Spectral Retention: Polycarbonate material absorbs almost no visible light (400-700nm) but has high transmittance for long-wave infrared, which is beneficial for daytime heat accumulation in greenhouses.
3. Core Advantages: Why Is It the Ideal Choice for Greenhouse Covering?
A. Impact Resistance and Hail Protection
Hail is the biggest fear for glass greenhouses. Polycarbonate is known as "unbreakable glass" or "bullet-resistant glass." The impact strength of this twin-wall sheet is over 200 times that of ordinary glass and 8-10 times that of acrylic sheets. Even if hit by large hail or accidental flying stones, the sheet will at most dent but will not shatter, effectively protecting crops and people inside.
B. Lightweight and Easy Installation
Weight per Unit Area: An 8mm thick twin-wall PC sheet weighs only about 1.5 kg/m², while 5mm glass with similar insulation properties weighs approximately 12.5 kg/m².
Installation Advantages: Lightweight not only reduces the load requirements on the greenhouse's main steel structure (saving steel costs), but also allows for fast manual installation, easy cutting, and short construction periods.
C. Flame Retardant Safety
Polycarbonate material itself is rated as difficult-to-ignite B1 class (according to GB 8624 or DIN 4102 standards). It self-extinguishes away from the flame and does not drip burning molten droplets that could ignite crops below. This is a critical safety indicator for densely populated locations like eco-restaurants or plant nurseries.
D. Flexibility and Adaptability to Arched Roofs
PC sheets have excellent cold bending properties. The twin-wall sheet can be cold-bent (without heating) along the direction of the ribs to form an elegant arched roof, which is both aesthetically pleasing and conducive to drainage and snow shedding. The minimum bending radius is typically 175 times the sheet thickness (e.g., an 8mm sheet can be bent to a radius of approximately 1.4 meters).
4. Typical Application Scenarios
A. Commercial Vegetable/Flower Greenhouses
Large multi-span greenhouses (Venlo type or arched) use this sheet for roof covering and partial sidewall glazing. High light transmission, insulation, and anti-condensation properties make it suitable for long-cycle, high-value crops such as tomatoes, bell peppers, and roses.
B. Eco-Restaurants and Agricultural Tourism Parks
These require a balance of light transmission, aesthetics, and safety. Clear or matte sheets combined with steel structures create bright and comfortable indoor environments. Impact resistance prevents injuries from accidental collisions that would shatter glass.
C. Home Gardening and Patio Sunrooms
DIY enthusiasts often use this sheet to build small flower tunnels or vegetable hot frames. Lightweight, easy to cut, and quickly assembled with aluminum profiles. The UV coating ensures the sheet remains non-yellowing for many years, maintaining good light transmission.
D. Aquaculture and Livestock Barns
Fish hatcheries and shrimp ponds require warm, well-lit environments. Dairy barns and poultry houses need natural lighting but protection from strong drafts. PC hollow sheets provide gentle, diffuse light while reducing animal stress.
5. Technical Parameters and Selection Guide (Typical Values)
| Parameter | Specification Reference |
|---|---|
| Thickness | 4mm, 6mm, 8mm, 10mm, 12mm, 16mm |
| Width | Standard 2100mm, customizable |
| Length | Standard 6000mm / 11800mm, customizable |
| Color | Clear, Opal, Lake Blue, Bronze, Green, etc. |
| UV Coating | Single-sided UV / Double-sided UV |
| Thermal Transmittance (U-value) | Approx. 3.0 - 3.9 W/m²·K (depending on thickness) |
| Light Transmission (Clear) | 80% - 88% (depending on thickness) |
| Coefficient of Linear Expansion | 0.065 mm/m·°C |
| Service Temperature | -40°C to +120°C |
Selection Suggestions:
For southern regions or structures with low insulation requirements, choose 4-6mm thinner sheets.
For overwintering greenhouses in northern regions, choose 8-10mm or thicker sheets. Consider triple-wall or quadruple-wall structures for extreme conditions.
If anti-condensation is required, choose an inner wall with anti-drip treatment.
6. Installation and Maintenance Guidelines
Correct Installation: The UV coating has a specific side; the UV side must face outward (towards the sun). Allow for expansion gaps during installation. Use dedicated aluminum profiles and EPDM gaskets for sealing.
Edge Sealing: After cutting hollow sheets, the open ends must be sealed with special anti-dust breathable tape or aluminum foil tape to prevent dust, insects, and moisture from entering the channels, maintaining cleanliness and light transmission.
Cleaning: Clean periodically with a mild detergent and a soft cloth or sponge. Avoid stiff brushes or high-pressure washers at close range.
Conclusion
The UV-Coated Twin-Wall Polycarbonate Sheet for Greenhouse is a representative product of Innovo's deep integration of polymer materials science with modern agricultural needs. With four major features-long-lasting UV resistance, excellent thermal insulation, ultra-high impact resistance, and lightweight, easy installation-it redefines the performance standards of greenhouse covering materials. For commercial growers seeking high yield, low energy consumption, and long service life, as well as home users wanting to build a durable, sunny garden space, this PC hollow sheet is an ideal choice that combines economy and functionality.
Choosing Innovo means selecting a greenhouse that greets each morning with abundant light for crop growth and securely locks in warmth through every winter.