Evaluation method for initial viscosity of formaldehyde-free adhesive

Abstract

The invention discloses an evaluation method for the initial viscosity of a formaldehyde-free adhesive. The method comprises the following steps: 1) cutting a single plate into sample plates, wherein the sample plates are divided into a sample plate for testing the bonding strength and a sample plate for hot pressing of a plate; 2) uniformly coating an adhesive in a template interval, and assembling and laminating to obtain laminating plates; 3) grouping the laminating plates, and pre-pressing one group of laminating plates at intervals to obtain pre-pressed plates; (4) after the prepressing is finished, testing the bonding strength of the pre-pressed plates and carrying out hot pressing on the plates. From the beginning of assembly covering and pressing to the pre-pressing of the laminating plates, the laminating plates are placed for different time, according to whether the bonding strength of the pre-pressed plates in the group is not lower than 70% of the initial pre-pressing bonding strength, the overall bonding strength of more than 80% of the pre-pressed plates in the group is not lower than 0.35 MPa, after hot-pressing the plates, the performance of the obtained plates meet the performance requirement of the corresponding plates in GB / T 9846-2015, and the initial viscosity of the adhesive is evaluated. The method provided by the invention can be used for simply and effectively evaluating the initial viscosity and determining the industrial production feasibility of a formaldehyde-free adhesive to a certain extent.

Description

technical field

[0001] The invention belongs to the field of plywood, in particular to the field of formaldehyde-free plywood, and relates to a method for evaluating the initial tack of a formaldehyde-free adhesive.

[0002] technical background

[0003] With the enhancement of people's health awareness, new formaldehyde-free and environmentally friendly decorative panels have attracted more and more attention. Plywood is the largest type of wood-based panel, and formaldehyde-free plywood has attracted much attention. At present, most of the adhesives for formaldehyde-free plywood on the market have problems such as poor initial viscosity of the glue, which affects the continuity of the board-making process and even limits the promotion of formaldehyde-free plywood adhesives.

[0004] How to effectively determine the initial tack of glue for plywood? At present, the more common initial tack test methods include "ring tack", "probe tack" and "rolling ball tack test". Loop t...

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