Analysis of the bonding problem between gypsum board and paper

Analysis of the problem of plasterboard not sticking to paper

The degree of adhesion between the gypsum board core material and the facing paper

It is an important indicator for measuring the quality of gypsum board.

There are many factors that affect the bonding between the paperboard and the board.

Among them, the performance indicators of the face paper

Taste characteristics of desulfurized gypsum

and process control during molding and drying.

All of these factors have a significant impact on the adhesion of the paperboard.

Today, we'll analyze this in detail together.

Problems and solutions affecting the bonding between gypsum board and paper

The performance of face paper >

A. The absorbency of the face sheet

If the absorbency of the facing paper is too high or too low, it will affect the adhesion to the core of the board.

The setting process of gypsum mortar is an exothermic reaction. During this process, gypsum crystals enter the pores of the facing paper, so the paper and board will bond firmly together after drying. If the facing paper has too high water absorption, a large amount of water in the gypsum mortar will be absorbed by the paper, and the water content in the gypsum mortar will decrease accordingly. This is not conducive to the setting reaction of gypsum, and the amount of gypsum crystals entering the facing paper will decrease, resulting in a non-sticky phenomenon. If the water absorption is too low, gypsum crystals will also have difficulty entering the paper surface, which is also not conducive to adhesion. Therefore, the water absorption should be controlled within a certain range.

B. Breathability of the face sheet

If the paper has too low air permeability, it will affect the adhesion of the plasterboard.

During the drying process of gypsum board, starch and excess moisture will migrate outward. If the air permeability of the paper is too low, the paper density will be relatively high, making it difficult for starch and excess moisture to escape. They will concentrate between the facing paper and the gypsum board, causing the paper to separate from the board.

C. Strength of the face sheet

Low strength of the inner layer of the facing paper will affect the adhesion of the gypsum board. Because of the low strength of the inner layer, it will be easy for it to fall off the surface of the gypsum core (the inner layer of the facing paper separates from the middle layer).

Therefore, the facing paper must be strictly inspected during the production of paper-faced gypsum board, and facing paper that meets the requirements should be used to minimize or even eliminate the impact of the facing paper on the adhesion of the board.

Jason paper-faced gypsum board uses low-grammage, high-strength gypsum board facing paper independently developed by China Resources Paper, a leading domestic gypsum board facing paper enterprise. Its products have advantages such as low basis weight, high tensile strength, good air permeability, excellent appearance quality, high interlayer bonding and surface strength. While improving the flatness and appearance quality of gypsum board, it effectively reduces the generation of low-grade boards and waste boards, making it the preferred facing paper material for high-grade gypsum board production.

The quality of gypsum powder >>

If the grade of desulfurized gypsum is too low, or if there are too many impurities, or if the content of harmful impurities such as Cl, K, and Na is too high, it will also affect the adhesion between the facing paper and the gypsum core.

High levels of potassium (K) and sodium (Na) ions in gypsum powder can cause sodium sulfate to readily absorb moisture and form sodium sulfate (Glauber's salt), leading to detachment of the facing paper from the board or sagging of the board. Chloride ions are also destructive; excessive chloride ion content in desulfurized gypsum affects its crystallization properties, resulting in slow setting and difficulty in forming the gypsum slurry. This reduces or even eliminates the strength of the paper-faced gypsum board, severely impacting the performance of gypsum products. Furthermore, chloride ions migrate to the surface of gypsum products during drying, affecting the adhesion between the gypsum core material and the paper-faced gypsum board, causing paper separation and significantly impacting the performance of the paper-faced gypsum board.

The gypsum board uses high-purity desulfurized gypsum from power plants. From raw materials to powder production to board production, it undergoes multiple screenings and strict controls to ensure it is free of harmful substances. The desulfurized gypsum has been tested and found to have chloride ion content that meets the standard requirements, ensuring that the gypsum board produced by the company has good adhesion and strength, and also greatly improving the safety of the gypsum board.

Control of production process >>

1. Poor bonding between paper and core can also be caused by factors such as excessively thin slurry, uneven foaming, and too many or too concentrated large pores in the board after drying.

2. The molding and drying speed cannot be adjusted in time with the fluctuations of the facing paper or slurry, resulting in a mismatch between the air permeability and water absorption of the facing paper and the drying speed, and a mismatch between the setting time of the gypsum slurry and the molding speed, which leads to the non-adhesion of the paper and the gypsum core or overheating of the board.

3. Over-heating of the gypsum board can cause some of the dihydrate gypsum to dehydrate into anhydrous gypsum, reducing the board's strength and making the paper prone to falling off. Strict control of the gypsum board drying process and parameters is crucial, with timely adjustments. The temperature of the boards inside the dryer must not exceed the dehydration temperature of the dihydrate gypsum, and the temperature at the outlet of the board must be controlled to not exceed 80℃.

4. If the drying speed is too fast, the starch will be drawn into the cardboard, leaving only a very small amount of starch on the paper surface and the plaster core, causing the paper to not stick and the peeling face paper to become brittle.

5. Improper use of additives or poor compatibility between additives can lead to poor paper adhesion.

After more than a decade of refinement and accumulation, Jason Gypsum Board has achieved internationally advanced levels in equipment, production processes, and product quality. Furthermore, the company employs domestic gypsum board experts as advisors to provide long-term guidance on production line operations. Its technical experts and core engineers all possess over 10 years of experience in production and management within building materials companies. All of these factors provide the strongest guarantee for product craftsmanship and quality.