SU433168A1 - METHOD OF OBTAINING POLYACRYLATE BLOCK - Google Patents

Description

one

The invention relates to the production of polyacrylate blocks, which can be used, for example, to seal various objects that require protection from atmospheric conditions and are not able to withstand high temperatures and pressure.

A known method for producing polyacrylate blocks by polymerizing acrylic monomers in bulk in the presence of peroxide initiators. In this method, the acrylate will be polymerized in the presence of peroxycarbonate, which decomposes into free radicals at low temperature. However, this method does not allow to obtain a defect-free large block, since upon reaching a conversion of 20-30%, a significant increase in the process speed, characteristic of the polymerization of acrylate, occurs, and, as a result, the heat released during the reaction increases, which leads to internal stresses, and therefore shells and bubbles.

The proposed method differs from the known one in that for improving the quality

The final product is carried out in the presence of 5-10 wt. % (L-methylstyrene, O, 05-O,% mercaptan, O, O5O, 5 wt.%, 4,4-dimethyl-6, b-ditertbutyl-2, 2-methylene bisphenyl arylphosphorous acid ester (based on the reaction mass).

The polymerization process is carried out at 200-° C for 25 -5 hours.

Example 1. A reaction mixture consisting of 36OO g of methyl methacrylate, 40 O g of d-methyl styrene, 4 g of dimethyl peroxy dicarbonate. South of n-lauryl mercaptan, 2O g 4,4-dimethyl-6, in β-ditert-2,2-methylenebisphenyl ester with (-naphthylphosphorous acid, placed in an atmosphere of air in a glass vessel and kept at 2 ° C for 5OO hour. After A solid transparent block of polymethyl methacrylate is removed from the vessel. Puzfi and rabbvin are absent in the block. The obtained polymethacrylate has an intrinsic viscosity in dichloroethane 2.18 and contains residual monomer within the limits of O 81, 2%. Example 2. The reaction mixture consisting of 19OO g butyl acrylate, 1OO g af metstietirol, 2O g dits cyclohexyl peroxide dicarbonate, 1 g of tert-dodecium mercaptan, 1 g of 4,4-dimethyl-6,6-d-tertbutyl-2.2-m% of phenylphosphoric acid phenyl ester are placed under a nitrogen atmosphere in a closed metal form and are dried at 40 ° C for 250 hours. Then the form is disassembled and a solid transparent block of polybutyl acrylate is extracted. The resulting polybutyl acrylate has an intrinsic viscosity in g 1 chloroethane 1.87 and contains residual monomer in the range of 1-1.25%. EXAMPLE 3 The reaction consisting of 37OO g of methyl methacrylate, AWGB by DG methylstyrene, dimetilperrksidikarbonata 1O g, 6 g of n lauryl ID g of 4,4-dimethyl-6, b-di-tertbutyl-2, 2 -metilenbisfenilovogo fetsilfbsforistoy ester acid is placed in a glass form and maintained at ZO C for 500 hours. Then, a solid transparent polymer block is removed from the mold, and there are no bubbles and shells in the block. The polymethyl methacrylate obtained has a hoerastic viscosity in dichloroethane 1.98 and contains residual monomer 1 in the range of 0.9-1.2%. Example 4 (control). A reaction mixture consisting of 40OO g of methyl methacrylate, South of dimethyl peroxide-carbonate, is placed at 2 ° C in a glass vessel. After about 300 hours, the reaction mixture is heated to 100-120 seconds. after which the polymerization is completed within 2-3 hours. The resulting block of polymethyl methacrylate has plenty of internal shells and bubbles. The subject of the invention is a method for producing a polyacrylate block by polymerizing an acrylic monomer in the mass in the presence of a peroxide isopropylate, characterized in that, in order to improve the quality of the final product, the process is carried out in 5 to 10 weight units. % s (-methylstyrene, O, O5-O, 25 wt.% mercaptan and O, 05O, 6 wt.% 4,4-dimethyl-6,6-ditertbutyl-2, 2-methylene bisphenyl ester arylphosphorous acid.