Molding, drilling, deburring, cleaning, spraying (silkscreen, printing), plating.
Except for the requirements of no toxic precipitation, no RHOS exceeding the standard, and to achieve a sturdy and durable structure if necessary, the other is the same as the general plastic treatment.
Plastic surface treatment
Plastics can be divided into two categories: thermoplastics and thermosets. In general, thermoset plastics are easier to glue than thermoplastics. But their surface energy are lower than glass, ceramics, metal and other hydrophilic materials, and their surfaces will often adhere to the release agent or escape plasticizer, so it is not easy for the adhesive to be infiltrated, thus affecting the strength of the bond. Therefore, it is generally necessary to carry out surface treatment of plastics. Due to the many varieties of plastics, a variety of properties vary greatly, so the surface treatment method is also very different. The following is an introduction to several common surface treatment of plastics.
[Method 1]
This method is mainly applicable to polyethylene, polypropylene, polyisobutylene, PVC, perchloroethylene.
The degreasing solvents for the above plastics are acetone and butanone.
After degreasing, it is treated with oxidizing flame: first, it is roughened with emery cloth, and then it is placed on the oxidizing flame for 3-5s, three times in a row. Then impregnated with 30% sodium hydroxide solution, 65-70°C for 3-5min, rinsed with cold water, then activated with the following solution, 65-70°C for 5-10min: chromic acid 10 Concentrated sulphuric acid 20 Water 40 Washed with water, then oxidized in the following solution at 70-75°C for 5-7min: potassium dichromate 10 Concentrated sulphuric acid 50 Water 340 Then in hot water at 70-75°C It is then washed for 5-7min in hot water at 70-75°C, washed with distilled water and dried at 65-70°C.
[Method 2]
This method is applicable to the same objects as above.
Treat for 90min at 20°C in the following solution: sodium dichromate 5 sulphuric acid (d=1.84 ) 100 water 8 Wash with cold water and dry at room temperature.
[Method 3]
This method is applicable to the same objects as above.
Exposure treatment in any of the following gases activated by corona discharge:
(1) Dry air, 15min;
(2) Nitric oxide, 10min;
(3) Wet air, 5min;
(4) Nitrogen gas, 5min.
Gluing should be carried out within 15min after treatment.
After treatment, it should be glued within 15min.
[Method 4]
This method is applicable to polystyrene and its modified varieties, such as ABS and AS.
Degreasing after sandblasting or emery cloth sanding.
Degreasing solvent: acetone, anhydrous ethanol.
After degreasing impregnate in chromic acid solution at 60°C for 20 min.
[Method 5]
This method is applicable to nylon.
Degreasing solvent: acetone, anhydrous ethanol, ethyl acetate, butanone, apply a layer of 10% nylon-phenol solution on the surface, keep it at 60-70°C for 10-5min, then wipe it off with the solvent (or apply a layer of resorcinol-formaldehyde primer on the surface again), and glue it immediately.
[Method 6]
This method is applicable to polyester film.
Degreasing solvent: acetone, anhydrous ethanol.
After degreasing, impregnate in sodium hydroxide solution at 80°C for 5min, then in stannous chloride solution for 5s.
[Method 7]
This method is applicable to paraformaldehyde and other acetal polymers.
Degreasing solvents: acetone, butanone.
Drying process at 120°C for 1h, then impregnated at 120°C for 5min in the following solution: p-toluenesulfonic acid 1 dioxane 10 perchloroethylene 200 Washed with cold and hot water, then dried with hot air.
[Method 8]
This method is applicable to PTFE and other fluorocarbon polymers.
Degreasing solvents: trichloroethylene, benzene, toluene, acetone, butanone, cyclohexanone.
After degreasing, impregnate for 30 min at room temperature in the following solution: sodium hydroxide 10 dienhydrin 8
Then dry at room temperature.
[Method 9]
This method is a radiation-induced grafting method. Applicable objects are the same as above.
The use of high-energy rays such as cobalt-60 rays or ultraviolet light below 2000?in the presence of styrene monomer, so that the surface of the fluoroplastic to produce a slight degradation of the active center at the end of the chain, the formation of a layer of transparent grafted **** polymer.
The color remains unchanged after treatment with this method, and the electrical properties do not decrease.
[Method 10]
This method is a fluorinated hydrocarbon - titanium polymer method. Applicable objects are the same as above.
The surface is impregnated in a solution containing tetrabutyl titanate, perfluorooctyl ester, and water to form a thin film layer of alkyl-titanium-oxygen and perfluorobranched polymer.
[Method 11]
This method is applicable to the object as above.
128g of refined naphthalene is dissolved in 1000ml of tetrahydrofuran (or ethylene glycol methyl ether, ethylene glycol dimethyl ether, dioxane), and 23g of sodium metal is slowly added under stirring in 2h, with the temperature being strictly controlled at 3-5°C. Stirring is continued after the addition so that the solution is blue-black. Under the protection of nitrogen, the PTFE is put into the treatment for 5min, then removed, rinsed with cold water, then washed with distilled water, warm air drying.
This method is stable and reliable, high strength of adhesive bonding, is currently the most used method in the surface treatment of fluoroplastics.
[Method 12]
This method applies to the same object as above.
After degreasing the fluoroplastic, the surface is coated with a layer of epoxy resin adhesive, heated at 370°C for 10min, and then heated at 400°C for 5min, so that the adhesive layer is melted into the surface of the fluoroplastic, and then glued.