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

Cost-effective industrial laminate

Cost-effective industrial laminate

  • 13/02/2019 09:10:01

The cheapest industrial laminates (Class X) are used in large quantities where the dielectric properties are less important. It is made from unbleached kraft paper and about 30% phenolic resin. It has …

Read more

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

Hot News

ABS sheet extrusion molding process control points

ABS sheet extrusion molding process control points

ABS sheet extrusion molding process control points(1) Feeding. The material should be fed in time to ensure that the hopper is not empty, in order to prevent the air from directly entering the drying cycle system, affecting the dry return air speed. Diffe

Preparation process of ABS sheet

Preparation process of ABS sheet

Preparation process of ABS sheet(1) The raw material is dried. ABS pellets are extremely hygroscopic and must be used before use.Dry. Drying can use hot air circulation oven or hot air hopper type reclaimed materialDryer. The drying process undergoes thre

Add waste materials to ABS sheet

Add waste materials to ABS sheet

Add waste materials to ABS sheet1. Material selection and performanceABS is an amorphous polymer. Under the action of heat and external force, it enters the viscous flow state from the glass state at room temperature through a high elastic state to form a

Plate (sheet) material forming process

Plate (sheet) material forming process

Plate (sheet) material forming processThe plastics of the production board (sheet) are mainly soft polyvinyl chloride, hard polyvinyl chloride, polyethylene.Alkene, polyamide, polymethyl, polycarbonate, cellulose acetate, etc., the first four varieties ar

Characteristics and uses of PTFE - Suspension PTFE

Characteristics and uses of PTFE - Suspension PTFE

Characteristics and uses of PTFEVariety: Suspension PTFEfeature:1. White waxy fine particle material;2. Poor strength;3. Self-lubricating, non-adhesive, stress cracking is good, dynamic and static coefficient is the lowest among plastics;4. Excellent resi

Tags