Control of dyeing method and dyeing effect

November 11, 2019

Control of dyeing method and dyeing effect

Control of dyeing method and dyeing effect:

（1）Dyeing method

1. Turn on the power supply of the electric water bath dyeing box and position the temperature controller at 80 ° C. A thermostat is installed in the dyeing box, which can automatically adjust the temperature to keep the dyeing solution at a constant temperature.

2. Clean the lens surface with alcohol and water.

3. Clamp the left and right lenses on the symmetrical positioner under the dyeing barrel cover respectively, and put them into the corresponding dyeing solution when the dyeing temperature is above 80 ° C. Control the dyeing time. After the dyeing degree is satisfactory, take out the lens, wash it with water and cool it.

（2）Control of dyeing effect

The dyeing time is different, the dye concentration is different, and the depth and concentration of dye particles penetrating into the lens are also different. With the same effect, the dye concentration is large and the time required is short. Long time, heavy color. In the product manual, there are certain descriptions of dye concentration, dyeing time and dyeing effect at different temperatures.

1、Dyeing principle of resin lens

The resin lens can withstand 150 ° C high temperature. When the temperature is 80 ~ 90 ° C, the resin lens is heated and the molecular gap expands. The dye particles dissolved in water can enter the gap between its molecules to make it colored. When the lens is cooled, the molecular gap is reduced, the color is fixed, and the dyeing is completed.

Dyeing can be either monochrome or gradient. Generally, the coloring depth is about 0.03 ~ 0.1 mm. Dyed lenses shall be resin lenses whose surface has not been hardened or coated. If hardening or coating is required, it shall be carried out after dyeing.

2、Dyeing solution and dyeing apparatus

（1）Staining solution and other reagents

1. Dye solution: aqueous solution of dye and accelerator.

2. Common dye combinations: yellow, brown, pink, green, blue and gray.

3. Accelerator: it is a kind of dyeing assistant, also known as surfactant. Its function is to reduce the surface tension of the dye, accelerate the infiltration speed of the lens, and make the dye particles dissolved in water enter the gap between the molecules of the resin lens faster, which is easy to color and fix.

4. Fading agent: a chemical solvent that can fade dyed lenses.

（2）Preparation of dyeing solution

According to the requirements of the manufacturer's instructions, add dyes and accelerators into the heated water in a certain proportion. Generally, the ratio of dye and accelerator is 20:1. Different manufacturers have different requirements, and the specific operation shall be carried out according to the requirements of the manufacturer's instructions.

（3）Dyeing apparatus

Dyeing utensils can be simple or complex. The simple ones can be a small aluminum pot and heater. The general standard dyeing equipment in optical shops is an electric water bath dyeing box (Fig. 14-24),

（2）Preparation of dyeing solution

（3）Dyeing apparatus

Dyeing utensils can be simple or complex. The simple ones can be a small aluminum pot and heater. The general standard dyeing equipment in optical shops is an electric water bath dyeing box,

There is a control panel (composed of power switch, thermometer, temperature controller, timer, etc.); The water bath box generally has six buckets, all of which are made of stainless steel; A lens locator with symmetrical design is arranged under the bucket cover; There is a movable lifting controller.

3、Mixed dyeing

Dyeing method: first put the lens into one kind of dyeing solution, after dyeing for a certain time, take out the lens from the dyeing solution, wash it with clean water immediately, and then put it into another kind of dyeing solution. After a certain period of time, take out the lens and rinse it with clean water.

4、Dye gradient lens

The most commonly used method is the automatic dyeing method of lens up and down lifter:

1. Clean the processed left and right lenses, invert and symmetrically fix them on the lens locator under the dyeing barrel cover.

2. Connect the hook of the dyeing barrel cover with the hook of the rising and falling transmission line of the upper and lower lifters, and keep the lens stable.

3. Adjust the position of the fixed pulley, set the initial position height of the lens, control the depth of the lens into the liquid level, and set the lens dyeing time. Generally, the dyeing position depth is set at 2 / 3 of the lens depth, because the lens is inverted at this time. When looking straight at the lens in the future, the dyeing position is located 1 / 3 above the lower edge of the lens. Although the position is set at 1 / 3 above the lower edge of the lens, due to the penetration and fumigation of the dye, this part of the lens will also form a color gradient from deep to light until the bottom edge.

4. After the preparation is completed, press the timer button, and the lens will move up and down according to a certain lifting cycle driven by the upper and lower lifters to control the color gradient; At the same time, the lens also vibrates up and down according to a certain frequency and amplitude to smooth the change of dyeing gradient. As shown in Figure 14-26, "> is a schematic diagram of the lens motion curve drawn with time as the abscissa when the up and down vibration of the lens is not considered, and this curve fluctuates in sine or cosine. The upper part of the lens is soaked in the dye for a long time and the lower part of the lens is short.

5、Fading treatment

The function of fading agent is to fade the lens. Once it is found that the dyeing effect is not ideal, such as too dark or uneven color, the dyed lens can be put into the water solution of fading agent configured in proportion in advance and at a temperature between 80 ° C and 90 ° C for fading. Fading agent can only lighten the color of the lens, but can not completely restore it to the original colorless state. Just as the lens surface cannot be dyed after hardening or coating, the lens surface cannot be faded after hardening or coating.

6、Color blending

1. Three primary colors: red, yellow and blue (color picture 14-7).

2. Intermediate color: the addition of two primary colors:

Red + yellow = orange

Yellow + blue = green

Red + blue = Purple

3. Multicolor: the addition of two intermediate colors:

Orange + Purple = red grey

Orange + Green = yellow grey

Green + Purple = blue grey

4. Complementary color: when two primary colors are added and compared with another primary color, it is called complementary color (contrast color).

Purple - yellow, orange - blue, green - red

7、Common colors

The most commonly used tinted lenses are gray, brown and green.

The choice of the color of the lens mainly depends on the wearer's personal preference. It is also related to the nature of ametropia and the use environment. For example, the vision of myopia with brown lenses is clearer, and that of hyperopia with green lenses is clearer. The light yellow lens can increase the contrast of visual objects, which is suitable for drivers driving at night and in foggy days and some people with low vision. When walking in the snow, the best lens color is gray, which can prevent reflection in the snow and increase the contrast of visual objects.

8、Dyeing properties

1. Light transmission and dyeing concentration will change the transmission of the lens to visible light. According to ISO international standards, the transmittance of dyed lenses is divided into 5 levels, i.e. level 0 ~ 4.

Table 14-3 dyeing grade

Dyeing grade 01234

Light transmission range /% 80 ~ 10043 ~ 8018 ~ 438 ~ 183 ~ 8

2. Chromaticity restoration when selecting the color of dyed lenses, attention must be paid to the chromaticity restoration index, that is, when viewing objects of different colors through colored lenses, the chromaticity of the original color of the object can be maintained. This requires that the transmittance of the lens to other bands of the visible spectrum is relatively balanced. In general, the attenuation of light transmission of grayish green lenses in various visible light bands under sunlight is relatively uniform. However, some stained lenses are different, such as rose colored ones. When wearing them to see objects in the sun, the wearer will reduce the chromaticity of green and blue in some objects, making the wearer feel that the chromaticity of the objects they see is "warm".

3. Dyeing sequence when dyeing mixed colors

According to the principle of chromatics:

(1) Bright colors are adjacent to dark colors, bright ones are brighter, and dark ones are darker;

(2) Gray and bright colors are juxtaposed, the bright ones are more colorful, and the gray ones are more gray; The cold color and the warm color are juxtaposed. The cold one is colder and the warm one is warmer.

Therefore, when dyeing mixed colors, pay attention to the dyeing sequence. First dye dark, gray and cold colors to make the background color calm and thick, and then dye bright, bright and warm colors. For example, blue + pink = violet (lotus root). If you dye pink first and then blue, the background color will be pink, and the effect is not ideal.

9、Vortex ring removal dyeing process

The scattered light incident from the periphery of the lens is reduced, so that the vortex ring looks less and plays a beautifying role.

Specifically, the dye solution is put into the flat bottom container. It is better to have a heating device under it, suck the solution through the water pump, and rotate the lens with the lens center as the axis by mechanical or manual methods to make the periphery of the lens evenly dyed with a thin layer of color. Because it is peripheral dyeing, the liquid level cannot be too deep. It can dye ordinary resin sheets, or treat the periphery of hard sheets and coated sheets.

In addition to the vortex ring dyeing process, you can also dye the periphery of the lens with a dyeing pen.