Preparation method of modified urea formaldehyde resin for container bottom plate

A container bottom plate and urea-formaldehyde resin technology, applied in the direction of aldehyde/ketone condensation polymer adhesives, adhesive types, adhesives, etc., can solve the problems of long cold pressing time, poor aging resistance, and poor water resistance of urea-formaldehyde resin. Improve the initial adhesion, improve the brittleness of the adhesive layer, and improve the production efficiency

Inactive Publication Date: 2018-11-13
SICHUAN AGRI UNIV
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Problems solved by technology

[0003] Due to the strong hydrophilicity of the urea-formaldehyde resin molecules, the water resistance of the cured urea-formaldehyde resin is poor, and the glue layer is brittle, easy to crack, poor aging resistance, and the decomposition of methylol and methylene ether bonds in the urea-formaldehyde resin leads to artificial Disadvantages such as high formaldehyde emission of board products limit the application range of urea-formaldehyde resin to a certain extent
At the same time, in order to strengthen the bonding strength of the container floor, the actual production generally adopts the cold pressing-hot pressing process, but the long cold pressing time, slow forming, and low bonding strength limit the improvement of production efficiency

Method used

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  • Preparation method of modified urea formaldehyde resin for container bottom plate
  • Preparation method of modified urea formaldehyde resin for container bottom plate

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preparation example Construction

[0018] In an embodiment of the present invention, a method for preparing a modified urea-formaldehyde resin for a container bottom plate is provided, including synthesizing a low-molecular-weight urea-formaldehyde resin prepolymer modified by a toughening agent, using melamine, urea and a reinforcing agent to modify the urea-formaldehyde resin prepolymerization Body and other steps.

[0019] First, urea, toughening agent and aldehyde compounds are synthesized into primary molecular weight urea-formaldehyde resin: add 55~65 parts of aldehyde compounds, 15~25 parts of urea, and 0.5~5 parts of toughening agent into a three-necked flask, and use a basic catalyst for 5~ 10 parts, adjust the pH to 7.0~8.0, and raise the temperature to 95°C and keep it warm for a period of 100 minutes in total, so as to generate a large amount of the compounds required for the crosslinking reaction - hydroxy and dimethylolurea; then use 0.5~1 part of acidic catalyst to The pH value of the reactant is...

Embodiment 2

[0031] In this embodiment, 40 parts of urea, 60 parts of formaldehyde, 5 parts of toughening agent, 7 parts of melamine and 4 parts of reinforcing agent are used to synthesize the modified urea-formaldehyde resin for container floor, and the specific steps are as follows:

[0032] ①Addition reaction: use heating and alkaline conditions (pH=8.0) to dissolve urea and formaldehyde and mix them evenly, then react at a constant temperature of 95°C for 70 minutes;

[0033] ②Synthesis of primary molecular weight urea-formaldehyde resin prepolymer: Use acidic conditions (pH=5.0) to fully react the methylol urea generated in step (1) at 95°C, and stop the reaction when the viscosity appears smoky turbidity point. The stage reaction time is about 45 minutes;

[0034] ③Add the second batch of formaldehyde and urea, a certain amount of melamine and reinforcing agent to the mixed resin under alkaline conditions (pH=8.0). ), react until the precipitation turbidity point appears, and immedi...

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Abstract

The invention discloses modified urea formaldehyde resin for a container bottom plate. In addition, the invention also discloses a preparation method of modified urea formaldehyde resin for the container bottom plate. The method is characterized in that urea and an aldehyde compound are used as major raw materials; in the urea formaldehyde resin synthesis process, melamine, a toughening agent anda reinforcing agent are used for modification; the aldehyde compound and urea alkali-acid-alkali secondary polycondensation process is used for improving the urea formaldehyde resin condensation degree; meanwhile, the urea is added in batches, so that the prepared urea formaldehyde resin can realize fast curing and low formaldehyde release quantity at normal temperature. The preparation method hasthe advantages that the low-mole raw material proportion is used; the toughening agent and the reinforcing agent are used for modification; a secondary polycondensation synthesis process and a urea stage addition method are used; the prepared urea formaldehyde resin can be fast cured under the normal temperature condition; high bonding strength and low formaldehyde release quantity are realized.The basic flow process of the method approaches to a common process; the process is simple; the operation is convenient; the modification on the existing equipment is not needed.

Description

technical field [0001] The invention relates to a method for synthesizing a modified urea-formaldehyde resin, in particular to a method for preparing a modified urea-formaldehyde resin for container bottom plates. Background technique [0002] The container floor is the main load-bearing part of the container, which not only requires extremely high strength and rigidity, but also requires good durability. Urea-formaldehyde resin has the advantages of cheap and easy-to-obtain raw materials, simple manufacturing process, colorless and transparent, excellent adhesion to lignocellulose, and no pollution to wood. Adhesive for plywood. my country is a country rich in moso bamboo, accounting for more than 90% of the world's total moso bamboo. Moso bamboo is similar to tropical hard broad-leaved wood, and the growth cycle of moso bamboo is short. Generally, it can be matured in 3-5 years, and the strength is the highest in 6-8 years. Moso bamboo can be selectively cut every year a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G12/38C09J161/30
CPCC08G12/38C09J161/30
Inventor 陈玉竹赵松许善峰李竞张嘉琳王韵焯曾增杨蕴蕊
Owner SICHUAN AGRI UNIV
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