Solid Wood Laminated Timber

For different laminated wood processing equipment — high-frequency machines, room-temperature cold-press rotary laminating machines, main laminating lines for aromatic wood materials, manual clamping jigs, and more — the laminating adhesive product range provides strong applicability.

For different solid wood species — oily hardwoods, hardwoods, medium-hardwoods, such as teak, rosewood, zebrawood, hard maple, ash, Chinese oak, white ash, white oak, red oak, rubberwood, poplar, pine, Chinese fir, and others — the laminating adhesive products are specifically differentiated and applied to meet the strength requirements of each material.

All laminating adhesive series products are E0/F★★★★ environmental-grade, manufactured with no added formaldehyde. Bonding strength is tested and verified according to both the Japanese Agricultural Standards (JAS) cold-water immersion delamination test and boiling-water immersion delamination test. Combined with dedicated adhesive application equipment, they meet the refined production processes and high-efficiency capacity demands of factories — safe, stable, and efficient!

Adhesive Solutions for Solid Wood Laminated Stock, Related Processes and Recommended Adhesives:

Finger-Jointing Process Adhesives Standard finger-jointing requirements: 9630/9631/PG240 Higher-requirement finger-jointing: PG80L/SAP21300/SAP21390 Fully automatic adhesive-spread finger-jointing: 9630/PG240L/PG80L Wet-wood finger-jointing adhesive: 8130/8132

Laminating Process Adhesives Softwood laminating adhesive: SAP21300/SAP21330 Medium-timber laminating adhesive: SAP21390/SAP22471/PG185 Medium-hardwood laminating adhesive: PG386/PG134/PG1268 Hardwood laminating adhesive: PG1963-1/PG1973-8 Wet-wood laminating adhesive: 8170/8172

Supporting Products and Equipment Solid wood end-grain sealing wax: AC-25 Solid wood anti-cracking oil: AC-26 Release agent for high-frequency machines: RC-13 Solid wood moisture content tester: L609/L606/6-36% Equipment for solid wood laminating adhesives: Adhesive mixers / Adhesive spreaders

Common Problem Analysis

Laminated panels are prone to developing end-grain glue-line cracking after being stored for a period or shipped to different regions.

Cause of the Problem

• Moisture content relationship. When laminating, the moisture content is on the high side, 14–16%. After being stored or placed in a drier area, the change in moisture content produces a significant internal stress change that leads to wood cracking or glue-line cracking.

• The laminating surfaces are not smooth enough, with saw marks or planer chatter. After pressing, the laminating surfaces cannot achieve the recommended bonding strength. Then the internal stress change in the solid wood leads to cracking due to insufficient bonding strength.

• During laminating, the proportion of curing agent (crosslinker) in the laminating adhesive is too small, resulting in insufficient bonding strength at the joint surfaces. The joint surface strength is lower than the internal stress strength of the solid wood itself, making glue-line cracking prone to occur.

• The adhesive strength does not match the wood species; the correct adhesive with the corresponding strength requirement has not been selected.

Solution

• Control the moisture content of the solid wood during assembly at 10–12%. It is recommended to control it at 8–10%, to avoid large stress variations later that cause cracking. Before the next processing step, wrap the laminated panels with film to prevent them from absorbing moisture and regaining humidity.

• When laminating, ensure the joining surfaces are smooth and flat without any saw marks or planer chatter, and make sure the joining surfaces are clean and even.

• Periodically check the mixing ratio of the laminating adhesive base and curing agent every day; use precise measuring tools for proportioning.

• Before applying adhesives to different wood species, first conduct strength testing to verify that the required strength for that wood species is achieved, and only then proceed with large-scale application.