The characteristics and application of capillary screen photosensitive film

Screen printing is inseparable from screen printing, and screen printing is the basis of screen printing. There are two major types of photosensitive materials used in the current platemaking process: photosensitive adhesives and photosensitive films. The photosensitive film is coated with a precision coater on a polyester film base in a clean room using a precision coater, and then dried on a dryer at low temperature and rolled into a scale; when the screen is manufactured, it is used immediately. It's fast. Photosensitive film is characterized by a smooth and smooth screen printing surface, easy to control the thickness of the screen layer; after the resolution and resolution of the bridge is good, the pattern is sharp, not easy to form edge serrations, it is suitable for high-precision and halftone printing Edition; but it is not as good as photographic adhesives, and it is not suitable for large-volume products.

Caaillerr Films combines the advantages of both photosensitive and photo-sensitive films, namely, it has the advantages of a strong plate, a high resistance and high number of times, and a suitable for mass production. The plate making method has high precision, simple operation, convenience, and time-saving features, and is suitable for mass production of high-precision, high-density products.

Capillary Screen Photo Film (CaP eX)

The capillary screen photographic film is a direct-door process film that incorporates a sensitizer and an auxiliary agent. Its outstanding feature is capillary action. When the film is affixed to the wet screen, the film layer will grip the screen tightly as the mammary gland of the screen climbs due to the capillary effect. The bridging effect is good, and the climbing height can reach up to the thickness of the wire mesh. In three parts, this is equivalent to the effect of coating the photosensitive adhesive on both sides in the direct plate making method, thereby enhancing the binding force to the screen mesh yarn and the abrasion resistance of the film layer, thereby improving the printing durability of the screen plate. The capillary screen sensitive film has high resolution, good resolution, stable quality, and longer storage time.

Ordinary screen sensitive films have poor adhesion to the screen. The reason is that at the same time, the film only adheres to one side of the screen, so the strength is low and the resistance is poor. The following diagram shows two screens. Photographic film attached to the screen after the simple contrast diagram.

At present, there are many brands of capillary screen sensitive films on the market, such as diazo, new photosensitive resin and so on. British Ketutai company is an early professional manufacturer of screen printing system for the development and production of capillary screen sensitive film, and its capillary film layer is even. Film surface smoothness is good, suitable for screens of different materials such as polyester and stainless steel, and exposure time is short. Good tolerance, strong resolution, good solvent resistance and consistent print quality.

British Ketutai capillary screen photographic film has a variety of specifications, of which the most commonly used emulsion layer thickness is 18μ, 25μ, 35μ and 5μ four, polyester base thickness is child V, can be applied to different mesh network Yarn (Table 1), in order to meet the needs of different levels, different thickness requirements of screen printing products, the following briefly describes the use of capillary screen photographic film and processing technology.

Table 1



The number of meshes cm 104080120160
Inch 25100200300400
Film thickness 18μ
25μ
35μ
5μ

Aids plate materials and tools

British Ketutai company's capillary screen sensitive film recommended the use of its supporting plate material, in order to achieve the best quality results, of course, the use of other manufacturers of auxiliary plate material effect is quite good.

(1) Grinding paste: (Autoprep)

Autopret Grinding Paste is an ideal screen roughening agent. The abrasive particles are very fine and have little damage to the screen mesh yarn, and the roughening effect is ideal. It is applicable to various chemical fiber mesh yarns.

(2) Multi-purpose pre-degreaser asks NIVersal Mesh (plep)

It is a non-toxic liquid degreasing agent. It is composed of surfactant and inorganic substance with strong detergency. It can not only degrease but also keep the screen moist, making the screen surface have good hydrophilicity. In a variety of chemical fiber mesh yarn.

(3) Anti-static dust-removing sticky cloth

Anti-static dust-removing and sticky cloth is a special dust-removing tool. It uses high-quality pure cotton cloth or chemical fiber cloth to remove the electrostatic agent's glue to make its surface form an imperceptible anti-static molecular layer. It is soft and has a certain degree of stickiness. Poisonous, insoluble in water, suitable for the removal of various types of films, photographic negatives, and the glass table of the plate making machine.

(4) Eliminating static and dustproof film

In addition to the static dust filter, it is a special netting tool for the simple screen sensitive film, which can prevent the screen sensitive film from being contaminated by dust, and can evenly press the screen sensitive film and paste it on the screen in a smooth manner. The trapped air caused by manual patching causes air bubbles or wrinkles and other diseases.

(5) AOtO Yang Po Exposure Calculator

The Autotype Exposure Calculator consists of 1, 0.7, 0.5, 0.33, and 0.25, 5 sharpness target columns. There is no color filter behind the first column and the exposure coefficient is 1. The remaining four gardens have a neutral density filter at the back of the target column, which reduces the light reaching the screen mesh to 0.7, 0.5, 0.33, and 0.25, respectively. Five different exposure effects are obtained in one exposure, so that the correct exposure effect can be selected, which saves time and accuracy and is suitable for the production of precision screen printing.

(6) Sealing glue: Fillers

Sealing glue is a slow-drying, water-soluble glue, which is also suitable for repairing broken screens and pinholes of screens, in addition to the general closure.

(7) Release agent, Autostrip;

Screen production process

The screen process of the capillary screen photosensitive film is the same as that of an ordinary screen photosensitive film. The process flow is as follows:

Screen Pre-processing ~ Photosensitive Film Patching ~ Drying ~ Exposure - Development and Drying - Renovation and Closure

(1) Screen pre-processing

a) Coarsening:

For example, in the use of poly-silk screens, the combination of the screen-sensitive film and the screen is mainly physical because its chemical properties are inactive and the net yarn surface is smooth. If you want to increase the adhesion, you must increase the roughness of the mesh.

Scrub the mesh paste on the two sides of the screen with a brush to make a circular motion, and then rinse it with high-pressure water, so that the surface is evenly roughened to increase the roughness of the mesh yarn and increase the contact area between the film and the mesh yarn.

The roughening treatment should be moderate, because the coarsening effect will cause damage to the screen mesh yarn and reduce the tension of the screen mesh plate. The old screen version mesh yarn does not need to be processed every time. In general, after every 5 to 6 blocks, Perform a roughening process.

b) Degreasing treatment:

The new screens are usually greased, and the used screens may leave prints or oil residues, which must be removed to make the screen meshes have good hydrophilic wetting properties.

Use brush to remove degreaser and brush back and forth on both sides of the screen for 3 to 5 minutes. Then use a high pressure water spray to spray. The degreasing effect can be observed by observing the distribution of water on the wire mesh. After washing the wire mesh, a uniform water film on the mesh yarn is used for wetting; if the shape is ball, the surface still contains oil stains, and the treatment must be continued. .

(2) Paste

There are many methods for sticking webs of capillary screens:

a) Place the screen photographic film on a raised platform with the latex film facing up, then place the dried screen on the film and use a spray bottle to spray the mist of water evenly to fully wet the film So far, the film is adhered to the screen by capillary action, and then the excess water in the screen is wiped off with a wiper, and the moisture around the woven screen and the frame is wiped to prevent excess moisture from flowing back to the screen. The film is focused on one part.

b) Spray the screen with a spray bottle, wipe the excess water around the screen and on the frame for later use.

The emulsion film is first placed on a raised platform face up, and then the wetted screen is first brought into contact with the corner of the film, and the capillary film is slowly bonded to the screen through the capillary phenomenon. The web is immediately in contact with the entire film because it can easily trap air, generate air bubbles, or wrinkle the film and cannot be used.

c) Place the screen screen on the platform, spray the screen with a spray bottle and form a uniform water film, and then contact the screen with one corner or one side of the film with the emulsion film face down and lift it diagonally or oppositely , And then slowly fit the screen, remove the air between the film and the screen so that the film is flat, this is also the most common method of mesh paste.

d) Using electrostatic dustproof film feeder, firstly roll the emulsion layer outside, take up the photo film with static electricity and dust filter, and set aside approximately 30.

The film of mm is on the outside, and then spray water to the screen to moisten, wipe the frame and the surrounding moisture to avoid excess water back to the screen, and the screen will be tilted, leaving the film in the first The outer end of the film is affixed to the net, and it is rolled up and pulled toward the entire screen, and the photosensitive film is flatly affixed to the screen. Finally, excess moisture is scraped away. This method is suitable for medium-sized screens.

(3) Drying

The screen mesh should be dried in a forced-air circulating oven under 40C for about 10 minutes, then the polyacetal film base should be torn off, and then dried for another 5 minutes to dry the film completely.

The dry film or polyester film base is easily peeled off from the emulsion film layer. If it is not easy to tear off, it means that the drying time is not enough to continue drying.

(4) Exposure

Use anti-static dust cloth to remove the dust on the exposure platen of the printing machine. Place the photographic film on the required position on the screen printing surface. Place a sponge foam on the ink screen surface of the screen plate and vacuum.

The best way to determine the correct exposure time is to use an exposure meter, first predict the correct exposure time, and then double up, first expose the meter and the photomask, and develop it in the usual way. After the development, the best one is selected among the five groups of target patterns to determine the optimal exposure time. If there is no exposure meter, refer to the table below for recommended exposure times.

Table 2 shows the exposure reference time for white silk screen making. If colored screens, such as orange screens, are used, the exposure time is approximately doubled.

Table 2



Light source distance 18μ25μ35μ50μ
150A carbon arc lamp 50cm1 (1/4) minute 1 (3/4) minute 2 (1/4) minute 3 (1/2) minute
50A carbon arc lamp 120cm2 minutes 2 (1/2) minutes 3 (1/4) minutes 5 minutes
124W high pressure mercury lamp 50cm3(3/4) minutes 5 minutes 6 minutes 10 minutes
2 kW Metal Halide 120cm