I. Preparation: Polycondensation reaction of cyanoacetate with formaldehyde in alkaline medium. Fourth, the formulation example <br> recipe one, KH-501 plastic a-cyano methacrylate 100 hydroquinone 0.02 SO2 0.01 Outdoor bench refers to the seating facilities used in outdoor places, often commonly found in parks, squares, leisure areas, scenic spots and other outdoor environments. The classification of outdoor benches can be introduced according to many aspects such as material, shape and function. Beach Bench,Deck Chair,Deck Bench,Waterproof Bench Foshan Shengshi Zhihui Technology Co., Ltd. , https://www.szhfurniture.com
In the structure of the product, there is a strong electron-withdrawing cyano group and an ester group, and it is easy to perform anionic condensation under water absorption or alkali catalysis.
Second, preparation : pure a - cyanoacrylate is a colorless, transparent, low viscosity, unstable liquid. A-cyanoacrylate is prone to anionic polymerization, and the storage stability of the monomer is closely related to moisture. The monomer with a water content exceeding 0.5% is very unstable. Alkaline stabilizers such as SO2, copper acetate, P2O5, CO2 must be added. For methanesulfonic acid and the like, a-cyanoacrylate may also undergo radical polymerization, and a polymerization inhibitor, hydroquinone, must be added.
A-cyanoacrylate has a very small viscosity and is easily lost as an adhesive. Polymers must be added as thickeners such as organic glass molding powder (5-10%); to increase the toughness of a-cyanoacrylate, A toughening agent such as tricresyl phosphate, dibutyl phthalate is added. DOP and so on.
Third, the curing reaction and performance
Curing by anionic polymerization, the polymerization of water or basic substance adsorbed on the surface of the adherend is rapidly completed at room temperature.
A-cyanoacrylate (cyanoacrylate) is the adhesive with the shortest curing time at room temperature. Its ester group may be methyl ester, ethyl ester, propyl ester, etc. The methyl ester has the fastest curing speed and heat resistance, but the adhesive layer is brittle. As the carbon chain grows, the flexibility of the adhesive layer is good. Currently, a-cyanoacrylate is mainly used.
a-Cyanoacrylate is stored as close as possible to water vapor and stored in a PE container. However, PE has good air permeability, which makes it easy for water vapor to penetrate and reduce the quality. Its storage period is only 3-6 months. 
Formula two, 502 glue a-cyanoethyl acrylate 100 tricresyl phosphate 15 methyl methacrylate 7.5 hydroquinone 0.02
SO2 0.01
Formula 3, 504 hemostatic glue a-cyanobutyl acrylate 100 hydroquinone 0.02 SO2 0.01
Formula IV, 661 # plastic
A-isobutyl cyanoacrylate 100 hydroquinone 0.02 SO2 0.01
First, classification by material
1. Wooden bench: Wooden bench is one of the most common outdoor benches, usually made of natural wood, with natural and environmentally friendly characteristics. Wooden benches are usually made of solid wood or artificial wood, and the surface is treated with waterproof and anti-corrosion, which can adapt to various climatic conditions in the outdoor environment.
2. Metal bench: Metal bench is made of metal materials, such as cast iron, steel, etc. The metal bench is durable, corrosion resistant, easy to clean and is suitable for all kinds of outdoor environments.
3. Stone bench: Stone bench is made of marble, granite and other stone, which has the characteristics of good texture and beautiful appearance. Stone benches are generally suitable for high-end places such as garden scenic spots and can be integrated with the surrounding environment.
5. Combined material bench: Combined material bench refers to the bench made of different materials, such as the combination of wood and metal, stone and plastic combination. Combined material bench can usually combine the advantages of different materials, more in line with the needs of different outdoor environments.
2. Classification by shape
1. Linear bench: Linear bench is the most common shape of bench, generally composed of a row of seats, forming a straight line arrangement. The linear bench is suitable for outdoor places with large pedestrian flow and can provide more seats.
2. Arc bench: Arc bench is an arc bench composed of multiple seats, usually used in a ring seat area or landscape area. The curved bench can not only provide comfortable seating, but also increase the aesthetics of the place.
3. Wavy bench: The wavy bench is a bench composed of multiple seats in the shape of undulating waves, giving people a sense of movement and flow. The wavy bench is suitable for parks, squares and other places that need to increase vitality and fun.
4. Round bench: A round bench is a round bench composed of a number of seats, which is usually used in outdoor recreation areas and can provide a place for groups to gather.
3. Classification by function
1. Leisure bench: Leisure bench is a common form of outdoor bench, it can provide comfortable seats, so that people can relax in the outdoor environment.
2. Viewing bench: Viewing bench is usually set in a scenic outdoor environment, providing comfortable seats for people to enjoy the scenery.
3. Sitting bench: Sitting bench is usually set in parks, squares and other places with large traffic, to provide people with a short rest and relaxation.
4. Cool pavilion bench: Pavilion bench refers to a form of combination of bench and pavilion, which can provide sunshade, rain prevention and other functions, suitable for outdoor leisure areas.
In short, the classification of outdoor benches can be divided from many aspects such as material, shape and function. Different outdoor environments and needs need to choose a suitable bench type to provide comfortable and beautiful seating facilities