阅读说明：本技术 一种印刷品表面脱色掉粉及划痕的修复方法 (Method for repairing decolored powder falling and scratches on surface of printed matter ) 是由 李旭 解明亮 周海涛 溥祖宏 于 2020-06-09 设计创作，主要内容包括：本发明提供了一种针对化学因素造成的印刷品掉色掉粉缺陷进行及时修复的方法和工艺,涉及印刷技术领域,包括缺陷印刷品预处理、表面处理剂制备以及表面处理剂的施涂等步骤,本发明通过利用现有的表面涂覆设备即可实现对缺陷产品的表面修复,无需额外的设备投资,对于因化学、环境因素导致的印刷品脱色掉粉等缺陷具有良好的修复效果,可有效降低瑕疵印刷品的废品率,降低印刷企业的经济损失；所述表面处理剂附着牢度高、光泽度高、柔韧性好,一方面可以适当降低使用量,同时提高其在印刷品表面的固化速度和附着力。(The invention provides a method and a process for timely repairing the defect of fading and powder falling of a printed matter caused by chemical factors, which relate to the technical field of printing and comprise the steps of pretreatment of the defective printed matter, preparation of a surface treating agent, application of the surface treating agent and the like, the invention can realize surface repair of the defective product by utilizing the existing surface coating equipment without additional equipment investment, has good repairing effect on the defects of fading and powder falling of the printed matter caused by chemical and environmental factors and the like, can effectively reduce the rejection rate of the defective printed matter and reduce the economic loss of a printing enterprise; the surface treatment agent has high adhesion fastness, high glossiness and good flexibility, and can properly reduce the use amount and improve the curing speed and the adhesion force of the surface treatment agent on the surface of a printed matter.)

1. A method for repairing decolored powder falling and scratches on the surface of a printed matter is characterized by comprising the following steps:

firstly, pretreatment of defective printed matter

Firstly, cleaning powder;

secondly, water is supplemented;

secondly, preparation of surface treating agent

The material comprises the following components in parts by weight:

nitrocotton liquid: 30-45 parts of a solvent;

wax powder: 0.2-0.5 part;

alcohol: 50-65 parts;

0.1-0.5 part of ultra-slow drying agent;

0.01-0.05 part of water-based defoaming agent;

preparing according to the following steps:

a. weighing the raw materials according to the proportion;

b. mixing and stirring: putting the nitrocotton weighed in the step into a container, adding half of alcohol, all the ultra-slow drying agent and the water-based defoaming agent, and stirring for dissolving;

c. transferring the uniformly mixed material in the step b into a high-speed dispersion machine, adding wax powder, dispersing at a high speed for 15-25 minutes, finally adding the residual alcohol to adjust the viscosity, and dispersing at a high speed for 3-8 minutes until the material is uniformly dispersed;

d. detecting fineness and viscosity, wherein the fineness is required to be 5-10 μm, and the viscosity is required to be 20s (measured by coating 4 cups at 25 ℃);

third, application of surface treatment agent

Firstly, removing impurities on the surface of a strip box to be coated by means of air draft, electrostatic adsorption and the like, and ensuring the coating effect;

secondly, placing the surface treating agent in a material groove, and coating the coating surface of the strip box by adopting a bottom feeding reverse roll coating mode;

thirdly, drying the barrel through electric heating or infrared rays, wherein the drying temperature is 80-100 ℃;

fourthly, cooling the barrel through a blowing system, and finally standing for 12 to 24 hours at room temperature to be collected and packaged.

2. The method for repairing decolored powder fall and scratches on the surface of a printed matter according to claim 1, wherein the step three is to apply a local surface treatment agent on the front surface of the barrel, and comprises the following steps:

carrying out light, chemical etching or die cutting on the applying roller according to the condition of the gold stamping position and the common ink position on the front surface of the strip box, removing 1/3-1/2 of an area corresponding to the gold stamping position on the front surface of the strip box, and not processing the common ink area;

secondly, coating the surface treating agent by matching with a flattening roller after the treated coating roller is normally installed, and carrying out the same subsequent treatment.

3. The method for repairing decolored powder fall and scratches on the surface of a printed matter according to claim 1, wherein the powder cleaning operation comprises the following specific steps: and (3) adopting surface powder cleaning equipment, introducing clean water into a water tank of the powder cleaning equipment, rinsing the defective product with the printing surface facing downwards once, and drying the rinsed product to a state before treatment.

4. The method for repairing decolored and dusted surfaces and scratches of printed matters according to claim 1, wherein the water replenishing operation comprises the following specific steps: the carton was fed from water and then press dried using two rubber rolls.

5. The method for repairing decolored powder fall and scratches on the surface of a printed matter according to claim 1, wherein the mass percent of the nitrocotton liquid is 25-35%, and the nitrocotton liquid consists of 1/8 nitrocotton, ethyl ester, butyl ester and isopropanol.

6. The method for repairing decolored powder fall and scratches on the surface of a printed matter according to claim 1, wherein the ultra-slow drying agent comprises a binary small molecular alcohol, a ternary small molecular alcohol, polyethylene glycol and glycerol.

7. The method for repairing decolored powder fall and scratches on the surface of a printed matter according to claim 1, wherein the wax powder is polytetrafluoroethylene modified PP micro wax.

8. The method for repairing decolored powder fall and scratches on the surface of a printed matter according to claim 1, wherein the surface treatment agent comprises, by weight, 39.74 parts of nitrocellulose liquid, 0.21 part of wax powder, 0.4 part of ultra-slow drying agent, 59.62 parts of alcohol, and 0.03 part of aqueous defoaming agent.

Technical Field

The invention relates to the technical field of printing, in particular to a method for repairing decolored powder falling and scratches on the surface of a printed matter.

Background

In a colloquial way, the quality of a printed matter is divided into three parts by printing and seven parts by plate making, intaglio printing is taken as one of printing processes, and the printed matter has the advantages of thick ink layer, bright color, high saturation, high printing plate printing resistance, stable quality of the printed matter, high printing speed and the like and occupies an extremely important position in the fields of printing packaging and image-text publishing; from the application aspect, gravure printing is mainly used for fine publications such as magazines and product catalogues, packaging printing and printing of securities such as bank notes and stamps, and is also applied to special fields such as decorative materials.

In the gravure process, people often see that the color of some printed matter layouts is lighter, even the color and the powder are seriously faded, the product quality is directly influenced, and the influence factors are mainly two aspects:

the first is that the printing plate is worn, the pictures and texts on the printing plate surface are worn, the opening of the inking hole becomes small, the depth becomes shallow, the area of the ink transfer unit is reduced, the total ink transfer amount is correspondingly reduced, the ink color becomes light, and the defects are caused; the main factors of plate wear include: printing plate surface friction, doctor blade pressure is too big, the linear velocity of printing plate roller and impression roller, the wearing and tearing of paper and printing ink to the printing plate etc. the defect that above-mentioned reason caused is often comparatively obvious, can discover rapidly in normal production process, and through seeking corresponding reason and in time make corresponding adjustment, its solution that corresponds reduces printing plate pressure and doctor blade pressure usually, eliminate the large granule in the printing ink and control printing ink's drying rate simultaneously, consequently can not cause the defect of batch product basically, can not cause big economic loss.

However, the second is related to more causes, and more causes are caused by chemical factors. The abrasion resistance is reduced or drying is incomplete during packaging due to improper control of the viscosity of the ink in the printing process, and the ink adhesion on the surface of a printed matter is reduced due to improper control of some external environmental factors. The consequences caused by the factors cannot be shown in time in the production process, the exposure of the defects has the characteristic of delay, so that the defects cannot be adjusted in time in the production process, and the defects can be shown only after the production of the product is finished and in the subsequent processing procedures, so that great economic loss is often caused. For example, in 2013, a certain known packaging material company provides a cigarette carton for a cigarette enterprise, serious powder loss occurs in the process of packaging cigarettes, so that the cigarette carton is shut down, the value of the cigarette carton in the batch is more than 200 million of renminbi, so that serious economic loss is caused to the packaging material company, and the loss is compensated by various repairing means within a specified time, but the good effect cannot be achieved.

Disclosure of Invention

In order to solve the problems described in the prior art, the invention provides a method and a process for timely repairing the defect of fading and powder falling of printed matters caused by chemical factors, and the defective printed matters are quickly repaired, so that the requirements of subsequent packaging procedures can be met, and the economic loss of manufacturers is reduced.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for repairing decolored powder falling and scratches on the surface of a printed matter is characterized by comprising the following steps:

firstly, pretreatment of defective printed matter

Firstly, cleaning powder;

secondly, water is supplemented;

secondly, preparation of surface treating agent

The material comprises the following components in parts by weight:

nitrocotton liquid: 30-45 parts of a solvent;

wax powder: 0.2-0.5 part;

alcohol: 50-65 parts;

0.1-0.5 part of ultra-slow drying agent;

0.01-0.05 part of water-based defoaming agent;

the nitrocotton liquid can increase the hardness of a surface film of the surface treatment agent after the surface treatment agent is dried;

the wax powder can improve the smoothness of a surface film of the surface treating agent after being dried;

the ultra-slow drying agent adjusts the drying speed of the surface treating agent;

alcohol is a diluent and controls the viscosity of the surface treatment agent;

the defoaming agent is used for eliminating bubbles in the surface treatment agent;

preparing according to the following steps:

a. weighing the raw materials according to the proportion;

b. mixing and stirring: putting the nitrocotton weighed in the step into a container, adding half of alcohol, all the ultra-slow drying agent and the water-based defoaming agent, and stirring for dissolving;

c. transferring the uniformly mixed material in the step b into a high-speed dispersion machine, adding wax powder, dispersing at a high speed for 15-25 minutes, finally adding the residual alcohol to adjust the viscosity, and dispersing at a high speed for 3-8 minutes until the material is uniformly dispersed;

d. detecting fineness and viscosity, wherein the fineness is required to be 5-10 μm, and the viscosity is required to be 20s (measured by coating 4 cups at 25 ℃);

third, application of surface treatment agent

Firstly, removing impurities on the surface of a strip box to be coated by means of air draft, electrostatic adsorption and the like, and ensuring the coating effect;

secondly, placing the surface treating agent in a material groove, and coating the coating surface of the strip box by adopting a bottom feeding reverse roll coating mode;

thirdly, drying the barrel through electric heating or infrared rays, wherein the drying temperature is 80-100 ℃;

fourthly, cooling the barrel through a blowing system, and finally standing for 12 to 24 hours at room temperature to be collected and packaged.

Because the gold stamping layer is arranged at the local position of the surface of the barrel, and the gold stamping layer does not have the phenomena of powder falling and decoloration, the gold stamping layer can be not coated with the surface treatment agent, and if full-plate coating is carried out, the gold stamping layer can drop because the drying speed of the gold stamping layer is slower than that of a common ink layer, so that the front surface of the barrel is preferably coated with the local surface treatment agent.

Application of a topical surface treatment comprising the steps of:

carrying out light, chemical etching or die cutting on the applying roller according to the condition of the gold stamping position and the common ink position on the front surface of the strip box, removing 1/3-1/2 of an area corresponding to the gold stamping position on the front surface of the strip box, and not processing the common ink area;

secondly, coating the surface treating agent by matching with a flattening roller after the treated coating roller is normally installed, and carrying out the same subsequent treatment.

Preferably, the powder cleaning operation comprises the following specific steps: and (3) adopting surface powder cleaning equipment, introducing clean water into a water tank of the powder cleaning equipment, rinsing the defective product with the printing surface facing downwards once, and drying the rinsed product to a state before treatment.

Preferably, the water replenishing operation includes the specific steps of: the carton was fed from water and then press dried using two rubber rolls.

Preferably, the mass percent of the nitrocotton liquid is 25-35%, and the nitrocotton liquid consists of 1/8 nitrocotton, ethyl ester, butyl ester and isopropanol; the slow drying agent comprises binary small molecular alcohol, ternary small molecular alcohol, polyethylene glycol and glycerol; the wax powder is polytetrafluoroethylene modified PP micro powder wax.

Preferably, the surface treating agent comprises, by weight, 39.74 parts of nitrocotton liquid, 0.21 part of wax powder, 0.4 part of ultra-slow drying agent, 59.62 parts of alcohol and 0.03 part of aqueous defoaming agent.

The invention has the following beneficial effects:

the method can realize surface repair of defective products by utilizing the existing surface coating equipment without additional equipment investment, has good repair effect on defects of decoloration, powder falling and the like of printed products caused by chemical and environmental factors, can effectively reduce the rejection rate of defective printed products, and reduces the economic loss of printing enterprises.

The surface treating agent has high adhesion fastness, high glossiness and good flexibility, can properly reduce the using amount on one hand, and simultaneously improves the curing speed and the adhesion force of the surface treating agent on the surface of a printed matter.

Detailed Description