SL-SF08 Spectacle Frame Perspiration Resistance Tester

The SL-SF08 Spectacle Frame Perspiration Resistance Tester is a laboratory instrument engineered to evaluate the resistance of eyeglass frames to sweat corrosion, verifying that frames remain safe for wear over two years or longer. By simulating prolonged exposure to artificial sweat, the tester helps prevent discoloration and plating loss that could otherwise compromise the wearer's health and safety.

Developed in accordance with standards such as ISO 12870, the machine incorporates advanced temperature control technology that maintains a consistent and stable testing temperature. An adjustable timer and thermometer allow the unit to satisfy the specific test duration and temperature requirements of different standards. The equipment uses German-imported, corrosion-resistant and impact-resistant glass containers, and is fitted with safety mechanisms that ensure safe operation while making the testing process more intuitive, enabling real-time monitoring and precise control of test progress.

The artificial sweat solution is comprised of the following components:

• Lactic acid, > 85 % mass fraction purity
• Sodium chloride (recognised pro analysis, p.a., grade or better)
• Water, conforming to grade 3 of ISO 3696

Using suitable containers, weigh (50 ± 0.1) g of lactic acid and (100 ± 0.1) g of sodium chloride and dissolve in 900 ml of water. Using the flask (8.3.1.3), make up to 1 l with water.

1. Cover the base of the container with the artificial sweat solution to a minimum depth of 10 mm so that the lowest part of the (lowest, if stacked) frame is not less than 12 mm above the solution. Place test sample 1, fitted with the test lenses, on the supports, with the sides open to the fullest extent (for frames with sprung hinges, opened to the fullest natural extent without activating the spring mechanism), and with the bottom edges of the sides resting on the supports (see Figure D.1). Ensure that the spectacle frame does not touch other samples or the container walls. Close the container, place it in the oven and maintain at (55 ± 5) °C.
2. After (8 ± 0.5) h, remove each sample and immediately wash with water. Dry without rubbing, using a soft cloth.
3. Within 30 min, examine each test sample under the inspection conditions described in Z.2. By comparison with an identical untested spectacle frame, check for and record any spots or change in colour — see the requirements in 4.11.
4. Replace the test sample(s) on the support(s), close the container and maintain the test temperature of (55 ± 5) °C for a further (16 ± 0.5) h. After completion of this second period, remove, clean and dry the samples without rubbing, using a soft cloth.
5. Within 30 min, examine those areas of each sample that are liable to come into prolonged contact with the skin of the wearer under the inspection conditions described in Z.2. By comparison with an identical untested spectacle frame, check for and record any corrosion, surface degradation or separation of any coating layer — see the requirements in 4.11.

• No spotting or obvious alteration in colour (except for loss of gloss to the surface) anywhere on the frame, excluding joints and screws, after testing for 8 h.
• No corrosion, surface degradation (e.g., roughness, orange peel appearance) or separation of any coating layer on the parts liable to come into prolonged contact with the skin during wear — i.e. the insides of the sides, bottom and lower parts of the rim, and the inside of the bridge — after testing for a total of 24 h.