Summer temperature rises, wpc material produces thermal expansion. The long wpc thermal expansion is larger because both ends are fixed, and the temperature stress (stress and expansion into proportional), when inflation after reaching a certain value, wpc buckling and bending deformation and bend with the increase of thermal expansion (bending deformation) increases. The temperature stress is released after the wpc bending. The stress on the neutral surface is zero. Due to bending, the pressure on the concave surface and the tension on the convex surface are generated. Due to the long-term effect of tension and pressure, the convex and concave surfaces produce tensile and compressive creep respectively, which makes the curvature larger and cannot be completely retracted when the temperature drops.

The temperature stress and creep are determined by the characteristics of the material itself. Controlling and reducing the linear expansion coefficient of wood-plastic materials can effectively control and reduce the temperature stress. Outdoor building temperature under 70 ℃, usually when the polymer materials of Tg (glass transition temperature) under the lower, the more prone to stress and creep.

The appearance colour, durability and design of wpc materials improve the appearance, colour and durability of wpc buildings and landscape. Outdoor wpc materials due to exposure to the sun and rain, strict environmental requirements; The inorganic colourant with excellent natural ageing resistance is usually adopted to ensure the durability of colour.

The phenomenon of powdering and fading often occurs, one is the ageing of the polymer of wood and plastic surface layer, and the other is the erosion of inorganic colourant by rainwater (commonly known as acid rain) with low pH value. In the design of wpc energy, anti-aging additives are usually evenly distributed. Ageing actually develops from the outside to the inside, so improving the anti-aging property of wpc surface layer is an important way to solve the fading of surface flour. At the same time in the colour, the formula to enhance the ability to resist acid rain.