Optically Clear Adhesive Optical Adhesive Die-Cutting Process

The explosive growth of global smartphones, wearable smart devices, and touch screens has brought ample orders and development opportunities for OCA optical adhesive products. OCA optical adhesive is made of optical acrylic adhesive without substrate. It is then laminated with upper and lower layers and a release film. It is a double-sided adhesive tape with high transparency and no substrate. It has moderate cohesive force and excellent flowability, making it easily deformable after extrusion. Currently, it is the best adhesive for touch screens and is mainly used for material bonding on touch screens to achieve capacitive touch sensing effects, requiring high cleanliness. In short, OCA is a special double-sided adhesive with optical transparency!

Composition of OCA Optical Adhesive

OCA optical adhesive is an important raw material for touch screens. It is made of optical acrylic adhesive without substrate. It is then laminated with upper and lower layers, each with a release film, making it a double-sided adhesive tape without substrate.

Upper release film and lower release film (also known as light release film and heavy release film)

It is understood that due to the purpose of optical adhesive, both the upper and lower release films use optical grade release films that have much higher light transmittance than ordinary release films. In terms of the thickness of the upper and lower optical grade release films, the upper release film (light release film) generally has a thickness of 50um and 75um, while the lower release film (heavy release film) has several different thicknesses, such as 75um and 100um.

Optical gel

Its main material is optical acrylic adhesive (or acrylic optical adhesive). Due to different applications, it has different thicknesses, such as 75um, 100um, 125um, 150um, 175um, 200um, 250um, etc.

Characteristics of OCA Optical Adhesive

1. Reduce glare, reduce the loss of light emitted by LCD or AMOLED displays, increase the brightness of the display, and provide high transmittance to reduce energy consumption.

2. Increase contrast, especially under strong light.

3. Have higher bond strength.

4. Avoid Newton's rings.

5. The surface of the product is smoother, without wrinkles, bubbles, impurities, and the display image is hardly affected by the OCA optical adhesive.

6. Borderless design, expand the visible area; good bubble removal effect, high TP yield, no yellowing, good reworkability.

OCA optical adhesive common problems summary

Q&A.

Light leakage, crease, indentation, glue overflow, white spots, foreign bodies, pinholes, dents, bubbles, glue wrinkles, scratches.

1, light leakage (product shipped to the customer when the problem)

The solution:

① The customer's own design size is the lower limit plus the lower limit of the production size, resulting in the mold size design is small, should communicate with the customer in advance to understand the actual size of the customer's product.

② There is a deviation in the measurement size of the company and the customer, you can take 10 products to the customer to measure the size, and then take back the company to measure the size, compare the size difference on both sides, and make a unified size standard.

③ Control the temperature of the processing environment, storage environment and transportation environment, and can control problems such as shrinkage.

2, creases, indentations, rubber wrinkles, scratches and other problems

The solution:

① The core is too small, resulting in wrinkles and other defects near the core parts, and use a 6-inch large core.

② If the raw material is placed on the plate, the weight of the raw material makes the material indentation, use the fixture to make the material suspended.

③ The knife die is not sharp enough or inappropriate foam resulting in indentation, the knife uses high-quality mirror knife (imported from Japan) wood knife die. The board is required to be 21-22mm thick, 2mm thicker than the average. The foam adopts low density and high elasticity pad foam. Generally, the density is 45° and the elasticity is 70%.

(4) When raw materials are splayed, scratches and indentations occur on the surface of the material. When raw materials are splayed, light release film should be added for effective protection to avoid surface scars. In addition, when cutting, pay attention to the tension of the material and minimize the phenomenon of rubber wrinkling.

⑤ Problems caused by die cutting, reduce the compound pressure, die cutting to avoid direct contact with metal or other fixed non-rotating items, increase the protection device.

3. Overflow glue

The solution:

① The knife die is not sharp enough or inappropriate foam resulting in indentation, the knife uses high-quality mirror knife (imported from Japan) wood knife die. The board is required to be 21-22mm thick, 2mm thicker than the average. The foam adopts low density and high elasticity pad foam. Generally, the density is 45° and the elasticity is 70%.

② Adhesive mold, to the knife and foam side of the release agent, to prevent mold adhesive.

③ Waste caused by overflow, change the waste Angle, speed up the die cutting speed, reduce the pause time.

④ Manual packaging causes poor extrusion, strengthen the proficiency of the technique and correct the wrong technique.

4. White spots and foreign bodies

The solution:

① The material in the die cutting generates static electricity during operation, which will adsorb dust and foreign matter in the air, add ion fan in the exposed position of the glue, and there is a filter behind the ion fan; At the same time, a dust-free baffle is added to the exposed position of the glue for isolation protection.

② Environmental factors, reduce the frequency of operators in front of the machine; Clean room Add or replace FFU (high efficiency filter).

5. Pinholes and depressions

The solution:

① Caused by dust foreign matter in the processing, add ion fan in the exposed position of the glue, and there is a filter behind the ion fan; At the same time, add a dust-free baffle to the exposed position of the glue for isolation protection.

(2) There is dust and foreign matter adsorbed on the rubber wheel, which causes the light release film to be dented when the film is fitted with the light release film for film change, and affects the colloid of the product, and the ion fan is added; Increase the cleaning frequency of the fit roller.

③ Take the product, the strength is too large to cause product indentation, packaging, pay attention to the strength of the product, carefully put.

6. Bubbles

The solution:

① When packaging, peeling the low mucous membrane causes bubbles, strengthening the accuracy and proficiency of peeling the low mucous membrane.

② Raw materials have bad bubbles, feedback to the supplier, ask for improvement.

③ Die-cutting produces bubbles, and the pad foam uses low-density and high-elasticity pad foam, generally using a density of 45 degrees and 70% elasticity.