3M Scotch-Weld Urethane Adhesive DP640 Brown

Overview

3M Scotch-Weld Urethane Adhesive DP640 Brown is a two-part, non-sag, thixotropic urethane adhesive that provides tough, flexible bonds with good adhesion to a wide variety of substrates, especially wood and many properly abraded and cleaned plastics; good adhesion can also be obtained on painted metals, ceramics and glass (priming of glass is required for maximum durability under moisture). It is designed for vertical and other applications where the bead must not slump or sag. According to the technical data sheet (September 2024) the mix ratio is 1:1 by volume and weight, with a worklife of 40 minutes (10 g mixed at 23°C), open time of 60 minutes, handling strength in 6-8 hours and full cure in 7 days at 23°C, and a cured Shore A hardness of 75 with a brown colour. Typical 7-day overlap shear strengths are 2,160 lb/in2 on aluminium, 1,960 on cold-rolled steel, 1,729 on ABS, 1,210 on polycarbonate, 1,150 on acrylic (PMMA), 1,180 on PVC and 900 on fibre-reinforced plastic; bell peel on aluminium is 64 lb/in width and elongation is 100%. Typical uses include flexible plastic or composite bonding, bonding composite panels to frames in transportation applications, wood, metal or composite door frames, and wood panelling. The same product is sold in bulk as 3M Scotch-Weld Urethane Adhesive 3549 Brown. Supplied as a 48.5 mL Duo-Pak; store at 16-27°C and use within 18 months of manufacture.

Specifications

Base Type

Two-part non-sag urethane (1:1)

Service Temperature

N/A

Technical Information

• 1:1 non-sag urethane; tough, flexible bonds; 40 min work life, 60 min open time
• Handling strength in 6-8 h; full cure in 7 days at 23°C; Shore A 75
• Overlap shear 2,160 lb/in2 on aluminium; bonds wood and abraded plastics; 48.5 mL Duo-Pak

Typical Applications

• Flexible plastic or composite bonding
• Bonding composite panels to frames in transportation applications
• Bonding wood, metal or composite door frames and wood paneling

Industries

Technical Documents