What are the requirements for compressive strength of hot melt adhesive particles in heavy-duty cardboard box stacking and sealing? Test cases of power plants one by one

Background: The warehouse is stacked on the sixth floor, and the bottom box mouth opens its own mouth

A small household appliance factory’s finished product boxes weigh 18 kilograms per box and are stacked in six layers in the warehouse. Use the original oneHot melt adhesive granulesAfter sealing and passing the factory inspection, the bottom box can be stored in the warehouse for two weeks. The seams of the top cover of the bottom box are gradually pushed open, forming a 2-3cm “mouth opening”. The cost of rework and resealing is not small. The problem lies in only assessing the sealing strength, without assessing the creep resistance under long-term stacking.

problem localization

• Original high initial adhesion fast solidification type: short-term tensile strength qualified, but insufficient adhesion force, slow sliding under long-term compression;
• Low softening point: The temperature at the top of the warehouse in summer is close to 40 ℃, and the adhesive layer further softens;
• Glue application method: Four point glue application, with force concentrated on four points, making it easy to pry open one by one.

adjustment plan

Technicians from Guangzhou Sunlife Trading brought samples to the factory for a control experiment: the original adhesive was changed to continuous adhesive strips along both sides of the box mouth, and the amount of adhesive applied was increased from 0.8g to 1.4g/box. At the same time, the heavy-duty sealing brand with high holding viscosity and softening point above 95 ℃ was replaced. Sunlife hot melt adhesive provides comparative data on the adhesion of three grades at a constant temperature of 40 ℃, and directly selects the one that meets the six layer stacking requirements.

Test results

The conclusion is very solid: heavy box stacking does not focus on instantaneous tensile strength, but on the adhesion and creep resistance at high temperatures; Each box of glue costs less than a penny more, saving the entire batch of rework.

Three actions for selecting adhesive for heavy-duty boxes

One is to inform the supplier of the actual working conditions: single box weight, stacking layers, maximum warehouse temperature, and storage period, which determine the direction of the brand; Secondly, it is required to conduct simulated stacking verification by placing heavy weights on the sample box for one to two weeks, which is closer to reality than the instantaneous tensile force in the laboratory; Thirdly, the width of the box opening overlap should also be taken into consideration. When the overlap is too narrow, even the best glue cannot withstand the stretching force.

Frequently Asked Questions

Q1: What are the main indicators for selecting adhesive for heavy-duty boxes?
Check the adhesion and softening point, and request the supplier to provide retention data at high temperature and constant temperature, rather than just looking at tensile strength at room temperature.

Q2: Can stacking layers be solved by adding glue?
Adding quantity is helpful but limited. When the adhesive type is incorrect, priority should be given to changing to a higher adhesive grade and then pairing with continuous adhesive strips.