Modified urea-formaldehyde resin adhesive for concrete formwork and production method of adhesive

Abstract

The invention discloses a modified urea-formaldehyde resin adhesive for a concrete formwork, which is mainly prepared from the following raw materials in parts by weight: 50 to 60 parts of formaldehyde with the mass concentration of 37 percent, 20 to 30 parts of urea with purity of 98 percent, 6 to 8 parts of melamine, 0.1 to 0.2 part of tackifier and 0.2 to 0.3 part of accelerant. The adhesive has an Uron-ring improved structure, so that the waterproofness of the formwork can be improved. The invention also discloses a production method of the adhesive, which comprises three steps of strong acid, weak acid and weak base. The reaction between the formaldehyde and the urea under a strong acid reaction condition can be effectively controlled by controlling temperature, pH value, charging speed, charging time and molar ratio. Meanwhile, two endpoint control indexes which are simple and convenient and are easy to operate are provided, and therefore processing implementing can be controlled conveniently and accurately.

Description

technical field

[0001] The invention belongs to the field of modified urea-formaldehyde resin adhesives, in particular to a modified urea-formaldehyde resin adhesive for concrete templates and a production method thereof. Background technique

[0002] In recent years, my country has become the world's largest producer of wood-based panels. In 2009, the national output of wood-based panels reached 115.4665 million cubic meters, of which plywood accounted for 44.5124 million cubic meters. Concrete (construction) formwork is the main purpose of plywood. It is mainly used outdoors. It must not only bear load but also withstand the sun exposure and sudden shower without cracking. At the same time, the concrete formwork must be disassembled and reusable for many times. Reduce infrastructure construction costs and wood consumption. In order to detect the bonding strength of concrete formwork, the national standard GB / T 17656-2008 for plywood for concrete formwork adopts the detect...

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