Laminate swelling



Sensitivity to moisture is an inherent problem in paper, which limits its application in components. Whenever the temperature and relative humidity of the surrounding environment change, the moisture content of the paper changes rapidly to achieve a balance in the new state. Excellent plasticizers, especially with any change in moisture content, all physical properties of the paper will change. When a hydrophobic resin (such as phenolic aldehyde) is sandwiched in the fiber network, the rapid exchange of moisture is greatly suppressed, but there is no loss. It only takes a long time to get a balance. However, the qualitative effect of moisture changes in the laminate is still evident. The higher the moisture content, the more plasticized the laminate and the lower its tensile modulus and stiffness.
Changes in the moisture content of plastic laminates can also cause changes in their physical dimensions. The change is inconsistent in all directions, and the change in the thickness direction is the largest. The most stable direction of the laminate is equivalent to the longitudinal dimension of the paper machine. Typical variations for commercial decorative laminates are: 0.1 ft to 0.3% in the longitudinal direction, 0.7% to 1.0% in the transverse direction, and 5% to 10% in the thickness direction. This value is for the humidity to change from 2% to 98%. The actual test [6] used two samples: one humidity change was from 55% to 2%, and the other humidity change was from 55% to 98%. It takes a day to get a true balance of 55% to 2% humidity change, and a 55% to 98% humidity change takes 7 days. The inconsistent swellability observed in plastic laminates is directly related to the inconsistencies (i.e., anisotropy) of the cellulose fibers. The hard resin itself is isotropic. Due to the microscopic and submicroscopic structure of the fiber, it is difficult to change the size in the axial direction when the moisture content changes, but rapidly expands and contracts in the radial direction. There is no free space in the plastic laminate
Inter- or void, so any change in fiber size translates directly into a change in laminate size.

  • 30/11/2018
  • Recently
Click here to view Previous or Next

Related News

Casting PA film and production technology

Casting PA film and production technology

  • 21/12/2017 09:33:12

Casting PA film and production technology 1. Casting PA film and its raw materials used: PA film has the advantages of high strength, good toughness, good transparency, good heat resistance and cold…

Read more

Cast film mechanical winding device

Cast film mechanical winding device

  • 19/12/2017 09:21:48

Cast film mechanical winding device Corona treatment device: cast film after corona treatment, can improve the surface tension of the film to improve the printing of the film and together with other…

Read more

Downstream production line auxiliaries

Downstream production line auxiliaries

  • 18/12/2017 09:42:18

Downstream production line auxiliaries Thickness measurement device: In the high-speed continuous production process, cast film thickness measurement must be non-contact automatic tracking. Most o…

Read more

Casting film production line in the cooling device

Casting film production line in the cooling device

  • 15/12/2017 10:03:16

Casting film production line in the cooling device Casting production line in the cooling device mainly by the rack, cooling roller, peel roller, refrigeration system and air knife, auxiliary device…

Read more

Hot News

Removal of excess resin

Removal of excess resin

There are two main methods for removing excess resin from the surface of the web: the doctor blade and the squeeze roller. The scraper can be as simple as a pair of angle irons arranged to contact the web. Usually they are mounted on a common rotatable su

Dipping machine

Dipping machine

Plastic laminates are manufactured industrially, and the web is impregnated in a machine called a dipper or a dipper. It includes a paper roll unwinding device, a resin tank, a facility for removing excess resin, a drying chamber for evaporating most of t

Saturated impregnation and infiltration process

Saturated impregnation and infiltration process

The analysis of the addition of the resin to the paper web in the plastic laminate is based on the assumption that the two processes that occur are simultaneous and sequential. First, the so-called saturated impregnation is the rapid absorption of the res

Laminate pore size distribution

Laminate pore size distribution

In the early 1960s, many laminates used the properties of this paper to estimate the amount of resin they absorbed. They used a thin resin solution to fill all the voids of the paper with the resin solution and scrape off the excess solution. As long as t

Laminate paper handling

Laminate paper handling

The resin and the cellulose fibers are thoroughly mixed to obtain a laminate, and the web is usually immersed in a resin solution. The surface tension causes the web to absorb the resin solution and fill the porous structure of the entire paper. The exces

Tags