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Coated PVDC barrier packaging film applications and coating process, today we look at the Nanjing Suminoe Precision Machinery Co., Ltd. PVDC in the coating process, and will encounter those common problems and how to solve them?
Common problems and their solutions
I. Low transparency and gloss of film
Film transparency and gloss for sales packaging is very important for an indicator, because they directly affect the packaging on the display effect of the goods, PVDC coated packaging film is used in a large number of various commodities sales packaging, so PVDC coated packaging film transparency and gloss, is a need to pay attention to the performance of the indicator.
The reasons for low transparency and gloss of the film may be due to problems with the emulsion (formulation) or improper control of the production process conditions.
1. Emulsion problems
PVDC coated film transparency and low gloss, may be PVDC emulsion anti-adhesion agent silica dosage is high, when found low transparency and gloss, the first should be on the PVDC emulsion formula check, the amount of silica will be controlled in the range of 1-2%; improve the filtration and mixing of SiO2 dispersion to avoid uneven distribution of SiO2 is also a way to solve the film transparency and low gloss. Transparency and low gloss is also one of the ways to solve the problem.
2. Improper coating process
Too tight winding during coating construction is also one of the common reasons for the low transparency and gloss of PVDC coated films. Winding too tight, will make the film roll of almost no air between each layer of film to stay, and the occurrence of "uneven" coating of mechanical embedded, unwinding this embedded separation, thus destroying the smoothness of the surface, resulting in a decline in the finish of the product as well as an increase in haze. The problem of low transparency and gloss produced by too tight winding can be solved by adjusting the tension value, increasing the tension attenuation or reducing the roll pressure. www.susumino.com南京住野精工机械有限公司专业片板膜设备生产研发.
II. Coating line
The existence of coating line, on the one hand, the appearance of the film performance decline, at the same time the existence of coating line, may also make the coating produce weak points, which leads to PVDC coated packaging film barrier property of a substantial decline, therefore, high-quality products do not allow the existence of obvious coating line.
New doctor blade burrs, or used doctor blade there is a dry solid coating, doctor blade has a micro-incision, coated fabric itself is dirty, between the doctor blade and coating roller solid particles and coating roller blocking plate, etc., may be in the PVDC coated film on the surface of the coating line can lead to the generation of the corresponding targeted measures to be resolved. Such as burrs and micro-ported doctor blade grinding repair, if necessary, replaced with high-quality doctor blade, strict management and filtration of latex, to prevent the coating roller blocking plate (appropriate reduction of cold water temperature, short downtime to keep the plate roller rotating, immediately after the shutdown thoroughly cleaned, to ensure that the dryness of the primer coating, etc.). www.susumino.com南京住野精工机械有限公司专业片板膜设备生产研发
III. Leakage of coating
As the name suggests, the leakage of coating that is part of the surface of the coated film is not covered by the PVDC coating, the harm of leakage of coating is that it will significantly reduce the barrier properties of PVDC coated packaging film, thereby losing the reliable protection of high barrier film on the packaged goods, and therefore is not allowed in the production process of coated PVDC barrier packaging film.
There are two kinds of leakage of coating, bottom coating leakage and top coating leakage.
1. Reasons for basecoat leakage
Substrate: small tension of surface film, small friction coefficient, poor uniformity of base film.
Equipment and process: A roll of the wrapping rubber skin is dirty or aging loss of elasticity; A roll drive friction failure; A roll drive friction is too small; oven section tension equipment is small; bottom coating at the guide rollers are not parallel and so on.
When the bottom coating is found to be bad, the above elements can be adjusted.
2. Reasons for leakage of top coating
Common problems and their solutions
I. Low transparency and gloss of film
Film transparency and gloss for sales packaging is very important for an indicator, because they directly affect the packaging on the display effect of the goods, PVDC coated packaging film is used in a large number of various commodities sales packaging, so PVDC coated packaging film transparency and gloss, is a need to pay attention to the performance of the indicator.
The reasons for low transparency and gloss of the film may be due to problems with the emulsion (formulation) or improper control of the production process conditions.
1. Emulsion problems
PVDC coated film transparency and low gloss, may be PVDC emulsion anti-adhesion agent silica dosage is high, when found low transparency and gloss, the first should be on the PVDC emulsion formula check, the amount of silica will be controlled in the range of 1-2%; improve the filtration and mixing of SiO2 dispersion to avoid uneven distribution of SiO2 is also a way to solve the film transparency and low gloss. Transparency and low gloss is also one of the ways to solve the problem.
2. Improper coating process
Too tight winding during coating construction is also one of the common reasons for the low transparency and gloss of PVDC coated films. Winding too tight, will make the film roll of almost no air between each layer of film to stay, and the occurrence of "uneven" coating of mechanical embedded, unwinding this embedded separation, thus destroying the smoothness of the surface, resulting in a decline in the finish of the product as well as an increase in haze. The problem of low transparency and gloss produced by too tight winding can be solved by adjusting the tension value, increasing the tension attenuation or reducing the roll pressure. www.susumino.com南京住野精工机械有限公司专业片板膜设备生产研发.
II. Coating line
The existence of coating line, on the one hand, the appearance of the film performance decline, at the same time the existence of coating line, may also make the coating produce weak points, which leads to PVDC coated packaging film barrier property of a substantial decline, therefore, high-quality products do not allow the existence of obvious coating line.
New doctor blade burrs, or used doctor blade there is a dry solid coating, doctor blade has a micro-incision, coated fabric itself is dirty, between the doctor blade and coating roller solid particles and coating roller blocking plate, etc., may be in the PVDC coated film on the surface of the coating line can lead to the generation of the corresponding targeted measures to be resolved. Such as burrs and micro-ported doctor blade grinding repair, if necessary, replaced with high-quality doctor blade, strict management and filtration of latex, to prevent the coating roller blocking plate (appropriate reduction of cold water temperature, short downtime to keep the plate roller rotating, immediately after the shutdown thoroughly cleaned, to ensure that the dryness of the primer coating, etc.). www.susumino.com南京住野精工机械有限公司专业片板膜设备生产研发
III. Leakage of coating
As the name suggests, the leakage of coating that is part of the surface of the coated film is not covered by the PVDC coating, the harm of leakage of coating is that it will significantly reduce the barrier properties of PVDC coated packaging film, thereby losing the reliable protection of high barrier film on the packaged goods, and therefore is not allowed in the production process of coated PVDC barrier packaging film.
There are two kinds of leakage of coating, bottom coating leakage and top coating leakage.
1. Reasons for basecoat leakage
Substrate: small tension of surface film, small friction coefficient, poor uniformity of base film.
Equipment and process: A roll of the wrapping rubber skin is dirty or aging loss of elasticity; A roll drive friction failure; A roll drive friction is too small; oven section tension equipment is small; bottom coating at the guide rollers are not parallel and so on.
When the bottom coating is found to be bad, the above elements can be adjusted.
2. Reasons for leakage of top coating
Base film reasons: bad uniformity; poor heat resistance; friction coefficient <0.4; base film deformation wrinkles when drying the base coating; oven tension is too large; base film deformation wrinkles; base coating oven air volume is too large; wind speed is too high; base film produces longitudinal folding.
Equipment and process; A roller friction is not large enough; A roller wrapping rubber skin is dirty or aging loss of elasticity; oven section tension setting is small; a pair of pressure rollers before coating pressure is insufficient or rubber pressure roller surface is not smooth, will cause the tension can not be effective segmentation, that is, the tension is traditional and out of control, caused by the bottom and top coating leakage; top coating roller speed speed and the machine's speed does not match, will also produce leakage of adhesive. www.susumino. comNanjing Sumino Seiko Machinery Co., Ltd. specialises in the production and research of sheet film equipment.
Nanjing Sumino Precision Machinery Co., Ltd. is a collection of scientific research, production, sales in one of the high-tech enterprises, has always adhered to the integrity, equality, the interests of the customer first business philosophy, in order to better improve the quality of the equipment, into a more professional and standardised production track. We set up a plastic sheet plate, casting, bi-directional stretching, non-woven nonwoven meltblown cloth, film composite, renewable granulation environmental protection recycling system and coating machine manufacturing system and other seven categories of equipment, independent research and development technology centre and production departments. We provide professional full set of technical solutions to meet the special needs of each customer. Among them, regarding the extrusion laminating manufacturing system, i.e. film laminator, the following production lines are available for customisation: PE double/triple co-extruded laminating production line, LDPE (3-in-1) laminating production line, PP,PE,PLA double-side laminating production line, aluminium foil high-speed laminating production line, PP spunbonded laminating production line, textile interlining fabrics laminating production line, hot-melt adhesive laminating production line, multi-layer extrusion laminating production line, graphene laminating production line and other laminating equipment. Graphene coated laminating line, Carbon fibre laminating line.
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