The production process of glass silver mirror is as follows:
Loading mirror-grade float glass→prewashing→polishing→cleaning→sensitization→activation→silver plating→copper plating→drying→primer spraying→primer drying→finish paint→topcoat drying→paint surface curing and cooling→mirror surface cleaning→ Unloading→inspection→packing.
(1) Loading mirror-grade float glass
The flat glass substrate is placed on the loading table through a mechanical suction cup and sent into the track. If it is float glass, the upper surface must face up. It has been proved that the lower surface of float glass cannot be plated with silver due to the existence of a large amount of tin or tin oxide; according to the running speed of the track, keep a gap of 1~3 cm between the substrates to ensure that the glass substrates or glass There is no collision between the silver mirrors, and at the same time, it is also ensured that the cleaning water or reaction residual liquid can be removed in time without interfering with each other.
(2) Pre-wash
Use a neutral detergent, preferably a special detergent for glass, to remove oil stains, artificial fingerprints and dust left on the glass substrate.
(3) polishing
Use the polishing agent to polish through the disc brush, so that the upper surface of the glass substrate produces a very fresh surface, laying a good foundation for the mirror plating.
(4) cleaning
Use a roller brush and clean tap water to remove impurities such as polishing agents on the glass substrate, and use deionized water (≥5 MΩ) to clean at least 3 times, so that the upper surface of the glass substrate has a very clean surface.
(5) Sensitization
Use a sensitizer, usually stannous chloride solution, to spray evenly on the surface of a glass substrate with a very high degree of cleanliness, and keep it for about 1 min. The stannous ions enter the silicon-oxygen network of the glass and combine with oxygen, causing the surface of the glass to generate A stannous ion-sensitized layer.
(6) activation
Spray the activator solution evenly on the glass substrate with the sensitization layer, and the stannous ions will reduce the metal ions in the activator to metal atoms, so that an activation layer is formed on the glass surface—a thin film of noble metal, the noble metal being palladium or silver , play a catalytic role in the subsequent silver plating process. Typical activators are palladium chloride and silver nitrate.
(7) Silver plating
According to the technical requirements of the production line, a certain amount of fresh silver-ammonia solution and a certain amount of reducing solution are sprayed onto the glass substrate with an activation layer at the same time, and after 2-3 minutes of oxidation-reduction reaction, the silver ions in the silver-ammonia reducing solution It is reduced to metallic silver and precipitated on the surface of the glass substrate to form a silver film reflective layer. The reaction expression is as follows:
Ag + R-COH → Ag↓ + R-COOH (1)
According to the requirements of my country's silver mirror standard, the content of silver attached to the surface of the glass substrate should be ≥ 700 mg/m and distributed evenly.
(8) Copper plating
Copper solution (copper sulfate solution) and reducing agent (copper reducing solution or reduced iron powder aqueous solution) are uniformly sprayed on the silver layer at the same time to produce a uniform copper layer. The reaction expression is as follows:
Cu + Fe = Cu↓ + Fe (2)
The copper layer is not only the protective layer of the silver layer but also the supplementary layer of the reflective layer. It is also the bridge layer between the silver layer and the paint layer. According to the requirements of the silver mirror standard in my country, the amount of copper attached to the silver surface of the glass substrate should be 200 mg/m around, and evenly distributed.
(9) drying
The copper-plated glass substrate is washed with deionized water to clean the residual iron powder, copper sulfate and reaction residue, and then blows off most of the residual deionized water with an air knife, and then enters the oven at 60-90 °C, and the glass substrate The residual deionized water on the chip is completely dried, and at the same time, the silver layer and the copper layer are denser through heating, and the combination with the glass substrate is stronger.
(10) Primer coat
The primer is evenly applied to the copper surface by a spray paint machine. The primer contains lead, which can adhere well to copper, so that the paint can be organically combined with the metal film and the glass substrate. The primer should not be in direct contact with people. According to the requirements of my country's silver mirror standard, the thickness of the primer should be ≥ 20 um.
(11) Primer drying
Set the baking temperature of the oven according to the nature of the primer used and the process parameters, so that the primer reaches the surface dry level before the topcoat, and is ready for the topcoat.
(12) Surface paint
The topcoat is evenly coated on the surface of the primer through the paint spraying machine. The topcoat does not contain lead and can be directly contacted with people. According to the requirements of my country's silver mirror standard, the thickness of the topcoat should be ≥ 20 um, and the sum of primer and topcoat should be ≥ 50 um.
(13) Topcoat drying
The baking temperature of the oven is set according to the nature of the topcoat used and the process parameters, so that the topcoat reaches the surface dry level before the exit of the oven.
(14) Paint solidification and cooling
The high-temperature baked glass silver mirror is cooled by high-pressure air knife, fan, fan and cooling water, so that the paint film is further condensed and solidified, and is ready for the next piece of packaging.
(15) Mirror cleaning
This process is to clean the silver, copper, lacquer, etc. left on the mirror surface due to water or solution sputtering or other reasons during the entire production process with ferric chloride solution and water to remove them.
(16) Next film
The produced silver mirrors are removed from the production line with manual or mechanical suction cups.
(17) inspection
Use instruments or manual inspectors to conduct production inspections on the next silver mirror, and detect those unqualified products and defective products that have stones, bubbles, scratches, glass tendons, bumps, transparent paint and coatings that do not meet the silver mirror standards. , which is a routine ex-factory inspection that must be carried out according to the requirements of the silver mirror standard.
(18) Packaging
Products that pass the factory inspection are packaged and put into storage according to the requirements of the silver mirror standard.
Qingdao Migo Glass Co., Ltd has state-of-art silver mirror production lines. If you are looking for high quality silver mirror products, please don't hesitate to contact our salespersons.
