Quaternary resin adhesives for the manufacture of plywood for container floors

Abstract

The invention discloses a quaternary resin adhesive used for manufacturing plywood for container bottom plates. The molar ratio of each component is formaldehyde: urea: melamine: polyvinyl alcohol = 1: 0.4-0.53: 0.15-0.17: 0.02-0.03 ; Preparation method: add formaldehyde and polyvinyl alcohol to the reaction kettle, heat, adjust the pH to 8.5-9.0, add 48-52% of the total amount of urea; when the temperature of the reaction solution rises to 79°C-81°C, add 43-47%; when the liquid temperature rises to 89°C-91°C, close the steam valve, keep warm for 55-65min, and keep warm at 90-93°C; adjust the liquid temperature to 88-89°C, pH to 5.9-6.2, and react 13-17min; adjust the pH value to 5.3-5.7, react for 13-17min; adjust the pH value to 4.0-4.4, until the reaction solution drips into 25°C water and becomes cloudy; after the cloudy shape is confirmed, adjust the pH value to 8.3-8.7, The liquid temperature is 88-91°C; add melamine, adjust the pH to 7.3-7.7, the liquid temperature is 80-82°C, and react for 18min-22min; add 3-7% of the total urea, adjust the pH to 7.2-7.5, and the liquid temperature 78-80°C, react for 10-15min; lower the temperature, adjust the pH to 7.0-8.5; lower the liquid temperature to 38°C-40°C.

Description

technical field [0001] The invention relates to a quaternary resin adhesive used for manufacturing plywood for the bottom plate of a container. Background technique [0002] In today's rapidly developing container transportation industry in the world, my country has become a major container manufacturing and exporting country. In 2007, my country exported 3.13 million containers, requiring more than 1.65 million cubic meters of plywood for container floors. In the next few years, The production quantity of containers still needs to be greatly increased. [0003] To manufacture a container, it is necessary to use plywood for the bottom plate of the container. The plywood for the bottom plate belongs to the structural load-bearing material and is one of the important components of the container. Therefore, the plywood used for the bottom plate of the container needs to have special properties such as good load-bearing, shock resistance, impact resistance, and weather resistanc...

AI Technical Summary

Problems solved by technology

[0005] First: The main chemical raw materials for the manufacture of phenolic resin adhesives are phenol, formaldehyde, and sodium hydroxide. Among them, phenol is a highly toxic substance. A certain amount of phenol will be released during the process of dissolving phenol, manufacturing phenolic resin adhesives, and producing plywood. Free phenol pollutes the environment. Workers engaged in related production suffer from allergies to varying degrees. Some workers are transferred because they are not suitable for related work.

[0006] Second: The phenolic resin adhesive has very strict requirements on the moisture content of the veneer. The moisture content of the veneer is required to be dried below 6-8%, which makes it difficult to dry the veneer, with a large dry shrinkage rate, serious warping and deformation, and difficult to dry. Storage, difficult processing, high energy consumption, otherwise, the slabs are prone to bubbling and delamination during hot-press gluing, resulting in serious waste

[0007] Third: Phenol is expensive, so the cost of manufacturing phenolic resin adhesives is also very high, making it unbearable for manufacturers

[0008] To sum up, in order to ensure the physical and mental health of employees, create a good natural environment, reduce energy consumption as much as possible, and reduce product production costs on the premise of ensuring product quality, in order to overcome the fact that ordinary melamine-urea-formaldehyde resin modified adhesives cannot meet the needs of containers Due to the shortcomings of the physical and mechanical properties of the plywood for the bottom plate, such as elastic modulus, static bending strength, and wet bonding strength, a new type of resin adhesive that can completely replace the traditional phenolic resin adhesive in the production of plywood for the container bottom plate is developed. The unshirkable sacred duty of those skilled in the art

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