The invention relates to a method for preparing a covering pressure sensitive adhesive

Hot melt pressure-sensitive adhesive has the advantages of simple preparation and construction process, fast curing speed, etc. It is especially suitable for field bonding with high automation requirements, and is very popular in the market. However, due to the special system of hot melt adhesive, the adhesive has problems such as poor solvent resistance and poor heat resistance. Patent CN101824280A published an UV-curable pressure sensitive adhesive and its preparation method.

The method uses a large amount of diluent of low viscosity acrylic ester, and the diluent of low reactivity has the problem of incomplete reaction in a short curing process. At the same time, the system uses a photoinitiator to achieve UV curing.

However, the decomposition residue of photoinitiator and the small molecules of residual photoinitiator have some problems, such as pungent odor. Patent CN104927697A published a kind of adhesive tape made of UV curable hot melt pressure sensitive adhesive for automotive wire beams. The system also has problems such as photoinitiator and olefin monomer. Meanwhile, the above patents all use monomer with low viscosity and single functional diluent.

To solve the above technical problems, the technical scheme of the invention is: a covering pressure sensitive adhesive made of the following raw materials in weight: Elastomer 20-40 parts, viscosifier 30-50 parts, softener 5-15 parts, crosslinking agent 2-5 parts, crosslinking aid 3-5 parts, coupling agent 0-2 parts, antioxidant 0.01-1 parts, pigment 1-5 parts, filler 3-10 parts.

The preparation method of covering pressure-sensitive adhesive comprises the following steps: the temperature of the reactor is set at 130℃, and the softener and antioxidant are put into the reactor from the charging port in turn according to the formula, heating and stirring, and nitrogen is passed into the reactor at the same time; When the heating temperature reaches 130℃, add the elastomer, and continuously stir to 160℃, maintain the temperature and stir for 110-130 minutes; After the elastomer is completely melted, reduce the temperature to 130℃, add the viscosifier and other raw materials, stir and maintain the temperature until it is completely melted; Under the condition of continuous agitation, vacuum the reactor until the vacuum pressure is 0.08MPa and keep it for 30-40 minutes.

After the stirring is stopped, continue to vacuum for 5-6 minutes and empty the vacuum. Then, pour the compressed air with the pressure of 0.1MPa into the reactor and discharge the material.