Introduction to the 12 most common pressure-sensitive adhesive coating mechanical coating heads

1、 Matching coating head

Suitable adhesive viscosity: 50-1000mPa. s

Coating thickness range: Wet glue 2-60 grams per square meter

Characteristics of coating head: The coating accuracy is still acceptable, the operation is simple, and it is easy to quickly switch between different width specifications of the coating substrate. However, the amount of adhesive is easily affected by changes in the viscosity of the adhesive, which requires high flatness of the coating substrate. The disadvantage is that it is prone to local glue leakage. The micro concave coating head on the market (with a diameter of 50mm) is also similar to the coating head, but the precision and diameter of the mesh roller are different. The micro concave coating accuracy is very high, and it can only apply low adhesive with a particularly large dilution dose

Application: Coating of polyethylene water-based protective film

2、 Gravure direct coating head

Note: The bottom is the rubber groove, the top one is the mesh roller, and the top one is the elastic rubber pressure roller

Suitable adhesive viscosity: 50-1000mPa. s

Coating thickness range: Wet glue 2-60 grams per square meter

Characteristics of coating head: High coating accuracy, suitable for coating substrates with low adhesive content, can solve the problem of glue leakage in the coating head, and can apply glue. The disadvantage is that it is inconvenient to replace substrates with different width specifications, and the machine needs to be stopped to replace the rubber roller

Application: Coating of oil-based protective films such as polyethylene and polypropylene

3、 Scraper type coating head

Note: The one above is a comma scraper

Suitable adhesive viscosity: 1000-300000mPa. s

Coating thickness range: Wet glue>20 grams per square meter

Characteristics of coating head: low coating accuracy, simple operation, coating substrates include release paper, PET, BOPP, PE and other materials, suitable for coating with a large amount of wet adhesive. Coating defects include thick adhesive at 1cm on both ends of the substrate, and adhesive lines due to garbage in the adhesive

Application areas: Sponge, foam, aluminum foil, fabric base, masking paper, double-sided tape, label production

4、 Upper feed reversal roller coating head

Note: The upper feeding reversal roller coating head has improved accuracy, mainly due to the control of the adhesive amount by the circular measuring roller on top, to avoid direct penetration of the substrate through the No. 3 coating head (uneven thickness of the substrate will affect the uniformity of the No. 3 coating method)

Suitable adhesive viscosity: 1000-300000mPa. s

Coating thickness range: Wet glue 10-300 grams per square meter

Characteristics of the coating head: The coating accuracy is higher than that of the No. 3 coating head, the operation is simple, and the coating substrates include release paper, PET, BOPP, PE and other materials. It is suitable for coating with high adhesive viscosity and high control accuracy. Due to the continuous rotation of its measuring roller, there are fewer occurrences of adhesive lines

Disadvantage: For example, some substrates rely on measuring rollers to transfer glue, which may not be able to transfer the glue

Application areas: Sponge, foam, aluminum foil, fabric base, masking paper, double-sided tape, label production

5、 Comma scraper reverse coating head

Suitable adhesive viscosity: 1000-300000mPa. s

Coating thickness range: Wet glue 10-300 grams per square meter

Characteristics of the coating head: The coating accuracy is better than that of the No. 3 coating head. The adhesive amount is controlled by a comma scraper measurement, and the coating gap can be automatically controlled. The accuracy is much better than that of No. 3, and the operation is simple. The coating substrate includes PET, BOPP, PE and other materials, which are suitable for coating with high adhesive viscosity and high control accuracy

Application: Coating of solvent based adhesives such as PE, BOPP, PET, etc

6、 Bottom feed reversal coating head

Suitable adhesive viscosity: 500-3000mPa. s

Coating thickness range: Wet glue 10-300 grams per square meter

Characteristics of the coating head: The coating accuracy is better than that of the No. 3 coating head. The adhesive amount is controlled by the measuring roller, and the coating gap can be automatically controlled. The accuracy is much better than that of the No. 3 coating head, and it is suitable for substrate backing adhesive with moderate viscosity. The disadvantage is that due to the bottom feeding and the rolling of the adhesive during coating, the volatilization amount is large, and the viscosity of the adhesive coating cannot be too high. The advantage is that the coated adhesive surface has good flatness

Application: Coating of solvent based adhesives such as PE, BOPP, PET, etc

7、 Lip reversal coating head

Suitable adhesive viscosity: 50-5000mPa. s

Coating thickness range: Wet glue>15 grams/square meter

Characteristics of coating head: Due to the fact that the adhesive is extruded from a mold, it has no solvent evaporation and is suitable for coating on the surface of irregular substrates. It is also suitable for coating adhesives with high evaporation of low boiling point solvents. The viscosity range of coating adhesives is also relatively wide, and the precision of narrow slit coating on the market can even be controlled to 1 micron of dry adhesive,

Application: Coating of solvent based protective films such as PET and BOPP

8、 Lip contact coating head

Suitable adhesive viscosity: 50-5000mPa. s

Coating thickness range: Wet glue>15 grams/square meter

Characteristics of the coating head: The difference from the No. 7 coating head is that the adhesive is directly applied to the substrate through the coating head, which is suitable for backing the substrate on rough and irregular surfaces. The coating accuracy can also be achieved up to 1 micron through narrow slit extrusion coating

Application: Adhesive backing or coating on fabric, paper, etc

9、 Soaking, extruding, coating and coating head

Suitable adhesive viscosity: 50-200mPa. s

Coating thickness range: Wet glue 1-30 grams per square meter

Characteristics of coating head: simple coating operation, substrate can be glued, high requirements for substrate fastness, substrate is prone to breakage after soaking and gluing

Application: Anti penetration coating treatment for paper (textured paper)

10、 Wire rod coating head

Suitable adhesive viscosity: 50-150mPa. s

Coating thickness range: Wet glue 10-60 grams per square meter

Characteristics of coating head: The coating accuracy is still acceptable, the operation is simple, and it is easy to quickly switch between different width specifications of the coating substrate. It is suitable for coating film materials with low adhesive viscosity and fast speed (200-300 meters/min) as backing adhesive,

Application: Coating of BOPP tape, coating of PE film

11、 Direct scraping coating head

Suitable adhesive viscosity: 50-100mPa. s

Coating thickness range: Wet glue 2-50 μ m

Characteristics of coating head: Suitable for backing adhesive of single-sided low viscosity coating

Application: Coating of release agent on the back of masking paper

12、 Curtain coating head

Requirements for adhesive: Dynamic wetting and static wetting should be very good (poor wetting can cause glue splitting), and the shear resistance should be good (poor mechanical properties can cause adhesive lumps and garbage)

Characteristics of coating head: uniform adhesive application, fast and stable adhesive supply, suitable for high-speed coating, generally coating speed of 700-1000 meters/minute

Application: Coating of BOPP tape and labels