Surface treatment and bonding technology of various materials

2.3 Polyolefins (Polyethylene and Polypropylene)

A, tannic acid oxidation liquid formula:

The limit surface tension of Na2CrO7 5 concentrated H2SO4 8 H2O 100 PE is Rc = 31 dyn/cm.
PE and PP were soaked in 66-71°C for 1-5 minutes or 80-85°C for 5-10 seconds or room temperature for 1-1.5 hours. When glued with epoxy adhesive, all of them are cohesively destroyed by the material itself. PS can be treated in an oxidizing solution of Na2CrO7 (10 parts) and concentrated H2SO4 (90 parts) for 3-4 minutes.

B, plasma method: processing time is about 5 seconds, the bonding strength can be increased by ten times to several dozen times, PP after treatment, helium from 0.7 rose 16.8mpa.

Bonded PE: Epoxy, vinyl acetate - ethylene copolymer, polyurethane, silicone and so on.

Adhesive PP: epoxy - polyamide, nitrile rubber, polyurethane and other plastic.

Adhesive PS: neoprene, cyanoacrylate, polyurethane, epoxy glue and so on.

Effect of Surface Treatment on Bonding Strength of PE

Adhesives Untreated Sandpaper Treatment Chemical Oxidation Plasma Epoxy Resin 3.2 13.8 33.7 32.6 Polyester 6.0 12.3 27.3 30.3 Phenolic - Nitrile 3.1 3.9 7.2 12.4

2.4, Polyester and Polycarbonate

Polyester Rc=43dyn/cm, Polyester surface has high crystallinity, must reduce crystallinity and increase polarity, can be soaked in 20% NaOH solution at 70-95°C for 10min. Polyester film (washing film) with organic Silicon, polyurethane, linear polyacetal, polyamide, hot-melt adhesives, etc. Polycarbonate degreased with sandpaper, with epoxy, polyurethane, unsaturated polyester glue.
2.5, polyether

Polyoxymethylene and chlorinated polyethers are more difficult to bond, and after degreasing with acetone, the surface is activated in the treatment liquid. Na2CrO7 5 Concentrated H2SO4 8 H2O 100

The polyoxymethylene treatment conditions are room temperature 10-20 seconds; the chlorinated polyether is 5-10 minutes at 65-71°C;

POM with nitrile rubber, polyurethane, epoxy and phenolic - nitrile rubber

The chlorinated polyether is bonded with nitrile rubber and neoprene.

2.6, polyamide

(1) Polishing with fine sandpaper on the surface of m-cresol resin primer, and then using epoxy adhesive;

(2) Soaking in 80% phenol aqueous solution and then washing and drying with water.

With nitrile rubber, polyurethane, polyamide, epoxy, phenolic - nitrile glue.

2.7, cellophane, polymethyl methacrylate, rigid polyvinyl chloride

Sanded by degreased sandpaper

Celluloid is made of nitrile rubber, neoprene, hot melt adhesive, polyurethane, etc.

Polymethyl methacrylate (organic glass): nitrile rubber, neoprene, epoxy, etc.;

Hard polyvinyl chloride: nitrile rubber, neoprene, white latex, polyvinyl chloride, polyurethane, epoxy glue and so on.
2.8, polyimide:

Degreasing with acetone, 5% in NaOH solution at 60-90 °C for 1 minute, the peel strength increased by more than 15 times, using epoxy glue.
2.9, natural rubber

After degreasing, use sandpaper to polish, then wipe with ethanol or gasoline or soak in concentrated H2SO4 at room temperature for about 15-20min, wash and dry, use epoxy, furan resin, neoprene, nitrile, polyurethane.

2.10, synthetic rubber

After degreasing, it is polished with sandpaper, soaked in concentrated H2SO4 at room temperature for 4-8min, washed and put in 20% ammonium hydroxide for 5-10min.

For the rubber with unsaturated carbon chain structure, it is glued with rigid epoxy glue; the bonding strength is close to or exceeds the cohesive strength of the rubber itself. If you need a soft connector available epoxy - polysulfide, epoxy - polyamide and other plastic.

Butyl rubber: Polyurethanes, silicones, etc.

SBR: Nitrile, Polyurethane, Silicone, etc.

Nitrile rubber: polyurethane, silicone, epoxy, phenolic - nitrile, etc.;

Fluorine rubber: Epoxy adhesive, cyanoacrylate adhesive;

Silicone Rubber: The surface is treated with plasma to increase the bond strength several times.

3, surface treatment and bonding of other materials

3.1 Glass:

After degreasing, soak 50% Na2CrO7 (3.5 parts) and 100 parts concentrated H2SO4 for about 15-20 minutes at room temperature. With polyurethane, water-soluble silicate, phenolic - epoxy, epoxy, phenolic - nitrile and other adhesives.

3.2 Ceramics: Surface treatment and bonding are the same as glass.

3.3 Cement products: sandpaper, epoxy, urea formaldehyde, silicone, water glass, etc. after degreasing.

3.4 Wood: Adhesives such as urea formaldehyde, phenol formaldehyde, melamine formaldehyde, and epoxy.