Method for improving gloss ink color fastness of printed color film, and use

Abstract

A method for improving gloss ink color fastness of a printed color film, and a use of the resulting printed color film for a tobacco packaging film, to improve the gloss ink color fastness of the printed color film. The printed color film is a composite BOPP film, and the method comprises the following steps: (1) pretreating the outer surface and inner surface of the composite BOPP film; (2) coating the outer surface and inner surface of the composite BOPP film using a surface-modifying coating, and high-temperature drying; (3) printing the outer surface of the composite BOPP film using an aqueous color ink, and drying, to obtain the printed color film.

Description

Method for improving gloss and color fastness of printed color film and use thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of tobacco, and particularly relates to a method for improving the gloss and black color fastness of printed color film and use thereof. BACKGROUND

[0002] The tobacco packaging film is generally BOPP film. The BOPP film has high tensile strength and impact strength, and is excellent in rigidity, toughness and transparency, and has high stiffness and high transparency. The BOPP film is colorless, odorless, tasteless and non-toxic, and is a commonly used packaging material in the tobacco industry.

[0003] Due to the light weight, non-toxicity, high mechanical strength, good dimensional stability and good transparency of the BOPP film, it is widely used in the packaging of candies, cigarettes, textiles and food. However, some properties of the BOPP film limit its application: (1) the biaxially oriented polypropylene film is a non-polar polymer, and the surface mainly exposes methyl groups, so the surface free energy is very low, resulting in poor hydrophilicity, printability, adhesion and dyeability of the surface, which greatly limits the application range and causes poor adhesion and printing performance; (2) the tertiary carbon atoms and methyl groups in the biaxially oriented polypropylene film have active H elements, which are prone to oxidative degradation under the action of external oxygen and the like, which is not conducive to long-term storage and use.

[0004] High-end cigarette products currently generally use printed color film for decoration and packaging. Gloss and haze are two important indicators of the optical properties of BOPP film. Low haze and high gloss of the film can make the appearance of the cigarette more high-end, and bring a bright visual effect to the cigarette package. Compared with traditional non-printed cigarette film, printed color film requires large-area printing of multiple colors, and the printing process of printed color film is complex. If organic solvents are used for printing, they will erode the macromolecular chains of the printed color film (the cigarette film is generally BOPP); therefore, water-based ink is generally used, and the drying procedure for printing is about 40 DEG C, which causes a certain degree of loss of the physical indicators of the printed color film, especially the performance indicators such as gloss.

[0005] Water-based ink needs to be quickly dried while having good resolubility; generally, ink with quick drying has poor resolubility; ink with good resolubility has poor water resistance, slow drying and high printing speed. The ink for inner printing requires good adhesion with the composite adhesive, cannot foam and cannot be peeled off. The ink layer for inner printing directly contacts the adhesive and cannot be corroded by the adhesive on the printed surface. The equipment for inner printing has high printing speed, and requires high quick drying of the ink, generally above 180 m / min.

[0006] In addition, the gloss and haze of the BOPP film have a tendency of deterioration with time. Therefore, it is necessary to develop a new anti-blocking masterbatch and apply it to the BOPP film, and to optimize the formula of the film to improve the optical properties and stability of the BOPP film.

[0007] To this end, the present application is proposed.

[0008] SUMMARY

[0009] The present application provides a method for improving the gloss of a printed color film, and the obtained printed color film has good light transmittance and gloss performance, and high ink color fastness.

[0010] The technical solution of the present application is as follows:

[0011] The present application discloses a method for improving the gloss and ink color fastness of a printed color film, wherein the printed color film is a composite BOPP film, and the method comprises the following steps:

[0012] (1) pretreating the outer surface and the inner surface of the composite BOPP film;

[0013] (2) coating the outer surface and the inner surface of the composite BOPP film with a surface modification coating agent, and drying at high temperature;

[0014] (3) printing the outer surface of the composite BOPP film with water-based color ink, and obtaining the printed color film after drying.

[0015] Preferably, the composite BOPP film is a three-layer film, the surface layer is a blended film of copolymerized PP, silicon dioxide, phenyl-modified silicone and hydrogenated petroleum resin; the core layer is a blended film of homopolymerized PP, antistatic agent and hydrogenated petroleum resin; and the inner layer is a blended film of copolymerized PP, phenyl-modified silicone and hydrogenated petroleum resin.

[0016] Preferably, the content of silicon dioxide in the surface layer is not higher than 0.08wt%, the content of phenyl-modified silicone is 0.05-0.10wt%, and the content of hydrogenated petroleum resin is 3.0-5.0wt%; the antistatic agent in the core layer is a mixture of alkyl diethanolamine and monoglyceride, the content of the antistatic agent is 0.35%-0.45wt%, and the content of hydrogenated petroleum resin is 10.0-15.0wt%; the content of phenyl-modified silicone in the inner layer is 0.10-0.20wt%, and the content of hydrogenated petroleum resin is 1.0-2.0wt%.

[0017] Preferably, the low-temperature plasma surface activation treatment is used for the pretreatment of the outer surface of the composite BOPP film, and CO2 is used as the gas; and the corona treatment is used for the treatment of the inner surface of the composite BOPP film, the voltage of the corona treatment is 10-20kV, and the frequency is 2-5kHz.

[0018] Preferably, the surface modification coating agent of step (2) is composed of water-based silane coupling agent, tetraethyl orthosilicate, solid acid and water, and the mass ratio is (5-10):(50-100):(5-10):(300-400).

[0019] Preferably, the water-based silane coupling agent is one of methyltrichlorosilane (MTS) or aminosilane; and the solid acid is ethylenediaminetetraacetic acid.

[0020] Preferably, the preparation of the surface modification coating agent comprises the following steps: dissolving the water-based silane coupling agent and the solid acid in water, then adding the tetraethyl orthosilicate drop by drop under high-speed stirring, and obtaining the surface modification coating agent after the reaction is completed.

[0021] Preferably, the coating of the surface modification coating agent of step (2) is performed by spraying; and the drying temperature is 80-100℃.

[0022] Preferably, the drying temperature after printing of step (3) is 40-50℃.

[0023] The second aspect of the present application discloses the use of the high-printing color film obtained by the method for improving the gloss and ink color fastness of the printed color film of the tobacco packaging film.

[0024] The beneficial effects of the present application are:

[0025] 1. The method of the present application improves the gloss of the printed color film, and the haze and transparency are not affected or slightly improved, and the ink color fastness is high. When used for the tobacco packaging film, the wearable capability is good. Note: Haze refers to the ratio of the scattered light flux deviating from the incident light direction to the transmitted light flux, expressed in percentage. Wearable capability refers to the performance of the surface of the film under the action of external friction; generally represented by the change of haze value, that is, the difference between the haze value after the film is rubbed for a certain pressure, speed and times and the original haze value before rubbing; the smaller the difference, the better the wearable capability and the higher the ink color fastness, and vice versa.

[0026] 2、The method for improving the glossiness of printed color film of the present application adopts three-layer composite BOPP film; the surface layer, the core layer and the inner layer all contain hydrogenated petroleum resin. The refractive index of hydrogenated petroleum resin is about 1.51, which is very close to the refractive index of BOPP (about 1.49), both of which are non-polar materials and have similar structures and good compatibility; hydrogenated petroleum resin is amorphous oligomer, and PP is semi-crystalline polymer, the addition of hydrogenated petroleum resin expands the amorphous region of the mixed material, significantly changes the aggregation state structure of the PP high molecular chain, partially dissolves the crystal structure of PP, reduces the melting point of PP (from 161-162℃ to 140-150℃), and refines the crystalline particles of PP, thus improving the transparency of PP, keeping the haze unchanged or reducing it. In addition, the surface layer and the inner layer also contain phenyl-modified silicone, wherein the kinematic viscosity of the phenyl-modified silicone is 100-280mm 2 / s, which has a more similar refractive index with PP, so that the glossiness of the surface of the BOPP film is improved, and the transparency is better.

[0027] 3、In order to improve the bonding performance between the surface modification coating agent and the surface of the composite BOPP film, the method of the present application performs low-temperature plasma surface activation treatment on the outer surface of the composite BOPP film, and the gas used is CO2; the inner surface of the composite BOPP film is subjected to corona treatment, and the voltage of the corona treatment is 2-100kV, and the frequency is 2-10kHz. Since the surface layer of the composite BOPP film of the present application is a blended film of copolymerized PP, silicon dioxide, phenyl-modified silicone and hydrogenated petroleum resin, after CO2 low-temperature plasma surface activation treatment, the surface modification coating agent has greater bonding capacity, and after printing with water-based color ink, the glossiness of the color film is higher, and the wear resistance is also improved. The inner layer is a blended film of copolymerized PP, hydrogenated petroleum resin and phenyl-modified silicone, and after corona treatment with a voltage of 10-20kV and a frequency of 2-5kHz, the surface modification coating agent has better bonding capacity, the peeling strength of the coating film formed later is high, and the "abrasion" phenomenon does not occur; at the same time, because the surface forms many active points after corona treatment, the active points are tightly combined with the surface modification coating agent, and there is almost no gap on the entire BOPP surface, so the gas barrier property is improved. Through analysis after CO2 low-temperature plasma surface activation treatment of the composite BOPP film, polar groups such as -COOH and -OH are successfully introduced on the outer surface of the composite BOPP film, the surface free energy is obviously improved, the interfacial bonding capacity of the surface modification coating agent with the outer surface of the composite BOPP film is improved, and the glossiness of the outer surface of the composite BOPP film is obviously improved.

[0028] 4、The surface modification coating agent of the present application is prepared by first dissolving water-based silane coupling agent and solid acid in water, and then adding ethyl silicate drop by drop under high-speed stirring (the rotation speed is generally 1000-5000 rpm) to first prepare a surface modification coating agent with good transparency and gloss. Analysis shows that the particle size of the particles in the surface modification coating agent is about 30 nm and the particle size is uniform.

[0029] 5、The outer surface of the composite BOPP film of the present application is coated with the surface modification coating agent after CO2 low-temperature plasma surface activation treatment, and then water-based color ink is used to print the outer surface of the composite BOPP film, which has less wear and tear and improved gloss. This is because the polar groups such as -COOH and -OH generated on the outer surface after CO2 low-temperature plasma surface activation treatment have good hydrophilicity, which makes the surface modification coating agent have good binding performance, and the coating is uniform; the printed color film obtained by using water-based color ink to print the outer surface of the composite BOPP film is firmly combined with the surface modification coating layer, and the ink color fastness is high.

[0030] 6、The composite BOPP film prepared by the method of the present application still has good gloss performance and ink color fastness after one year of natural aging. DETAILED DESCRIPTION

[0031] The preferred embodiments described herein are used to illustrate and explain the present application, and are not used to limit the present application. Other advantages, objects and features of the present application will be illustrated in the following examples, and will be apparent to those skilled in the art to some extent, or can be taught by the practice of the present application.

[0032] In order to improve the gloss of BOPP printed color film without losing wear resistance, the present application proposes a method for improving the gloss of printed color film, and obtains a high printed color film for tobacco packaging film, which can improve the gloss without losing its light transmission and wear resistance.

[0033] The method for improving the glossiness of the printed color film of the present application, the printed color film is a composite BOPP film, the method comprises the following steps: (1) pretreating the outer surface and the inner surface of the composite BOPP film; the composite BOPP film is three layers, the surface layer is a blended film of copolymerized PP, silicon dioxide, phenyl modified silicone and hydrogenated petroleum resin, the content of silicon dioxide in the surface layer is not higher than 0.08wt%, the content of phenyl modified silicone is 0.05-0.10wt%, and the content of hydrogenated petroleum resin is 3-5wt%; the core layer is a blended film of homopolymerized PP, antistatic agent and hydrogenated petroleum resin, the antistatic agent in the core layer is a mixture of alkyl diethanolamine and monoglyceride, the content of the antistatic agent is 0.35%-0.45wt%, and the content of hydrogenated petroleum resin is 10-15wt%; the inner layer is a blended film of copolymerized PP, phenyl modified silicone and hydrogenated petroleum resin, the content of phenyl modified silicone in the inner layer is 0.10-0.20wt%, and the content of hydrogenated petroleum resin is 1-2wt%; the outer surface of the composite BOPP film is pretreated by low-temperature plasma surface activation treatment, and the gas used is CO2; the inner surface of the composite BOPP film is treated by corona treatment, the voltage of the corona treatment is 10-20kV, and the frequency is 2-5kHz; (2) coating the outer surface and the inner surface of the composite BOPP film by using a surface modification coating agent, the coating is performed by spraying, and drying is performed at 80-100℃; the composition of the surface modification coating agent comprises water-based silane coupling agent, tetraethyl orthosilicate, solid acid and water, and the mass ratio is (5-10):(50-100):(5-10):(300-400); the silane coupling agent is one of methyltrichlorosilane (MTS) or amino silane; the solid acid is ethylenediaminetetraacetic acid; the preparation of the surface modification coating agent comprises the following steps: dissolving the water-based silane coupling agent and the solid acid in water, then adding the tetraethyl orthosilicate drop by drop under high-speed stirring, and obtaining the surface modification coating agent after the reaction is completed; (3) printing the outer surface of the composite BOPP film by using water-based color ink, and obtaining the printed color film after drying; the drying temperature after printing is 40-50℃.

[0034] Example 1: method for improving the glossiness of the printed color film (shrink film).

[0035] The three layers of the composite BOPP film: the surface layer is a blended film of copolymerized PP, 0.05wt% silicon dioxide, 0.05wt% phenyl modified silicone and 4.0wt% hydrogenated petroleum resin; the core layer is a blended film of homopolymerized PP, 0.40wt% antistatic agent (the mass ratio of alkyl diethanolamine to monoglyceride is 1:0.3) and 10.0wt% hydrogenated petroleum resin; the inner layer is a blended film of copolymerized PP, 0.15wt% phenyl modified silicone and 1.5wt% hydrogenated petroleum resin;

[0036] The modified coating agent is composed of water-based silane coupling agent (amino silane), tetraethyl orthosilicate, solid acid (ethylenediamine tetraacetic acid) and water, and the mass ratio is 5:100:10:300. The amino silane 5 g and ethylenediamine tetraacetic acid 10 g are added into 300 g (ml) of water to be mixed and dissolved, and then the tetraethyl orthosilicate 100 g is added drop by drop at 3000 rpm, and after the dropping is completed, it is stirred for 10 min again; thus a transparent slightly viscous surface modification coating agent is obtained.

[0037] The outer surface of the composite BOPP film is pretreated by CO2 low-temperature plasma surface activation treatment, and then the surface modification coating agent is sprayed to coat the outer surface of the composite BOPP film, and after drying at 90℃, the outer surface of the composite BOPP film is printed using water-based color ink (commonly used in the market), and after drying at 50℃, the printed color film is obtained.

[0038] Meanwhile, the inner surface of the composite BOPP film is treated by 50kV and 10kHz corona treatment, and then the surface modification coating agent is sprayed to coat the outer surface of the composite BOPP film, and dried at 90℃.

[0039] The printed color film is tested for gloss and light transmittance, and after natural aging for one year, the printed color film is tested, and the results are shown in Table 1.

[0040] The haze is tested according to the provisions of GB / T2410 Transparent Plastics: Test Methods for Transmittance and Haze of Transparent Plastics.

[0041] The gloss is tested according to the provisions of GB / T8807 Test Methods for Specular Gloss of Plastic Materials, and the incident angle is 45°. During the test, the incident and reflected light plane of the gloss tester test window should be parallel to the longitudinal direction of the film, and the black pad should have a gloss of not more than 0.2%.

[0042] Table 1 Test results of the printed color film obtained in Example 1

[0043] As can be seen from Table 1, the gloss of the composite BOPP film of the present application is much higher than the average level in the industry, and the haze is much lower than the average level in the industry. After aging for one year, the gloss and haze hardly change. This fully shows that the composite BOPP film prepared by the preparation method of the present application has significantly improved gloss and ink color fastness, and good aging resistance.

[0044] Machine suitability: The cigarette film samples for machine suitability test should be stored in an environment with a temperature of 22.0-27.0℃ and a relative humidity of 60%±5% for 24h before the machine test, and during the process, the quality defects of the cigarette film will not affect the normal operation of the packaging machine, and the effective operation rate of the equipment is improved, and there are no defects such as scattered packages and wrinkles that affect the quality of cigarette strips, boxes and packages.

[0045] Example 2: Method for improving the gloss of printed color film (shrink film).

[0046] The composite BOPP film has three layers: the outer layer is a blend film containing copolymerized PP, 0.05 wt% of silica, 0.05 wt% of phenyl-modified silicone, and 4.0 wt% of hydrogenated petroleum resin; the core layer is a blend film of homopolymerized PP, 0.40 wt% of antistatic agent (mass ratio of alkyl diethanolamine to monoglyceride is 1:0.3), and 10.0 wt% of hydrogenated petroleum resin; and the inner layer is a blend film containing copolymerized PP, 0.15 wt% of phenyl-modified silicone, and 1.5 wt% of hydrogenated petroleum resin.

[0047] The modified coating agent composition and preparation method are as follows: water-based silane coupling agent (amino silane), tetraethyl orthosilicate, solid acid (ethylenediaminetetraacetic acid), and water, with a mass ratio of 5:50:5:300. Amino silane 5 g and ethylenediaminetetraacetic acid 5 g are added to 300 g (ml) of water and mixed and dissolved, and then tetraethyl orthosilicate 50 g is added dropwise at 3000 rpm, and after the addition is completed, stirring is continued for 10 min; thus, 5 transparent and slightly viscous surface modification coating agents are obtained.

[0048] The outer surface of the composite BOPP film is pretreated by CO2 low-temperature plasma surface activation treatment, and then the surface modification coating agent is sprayed to coat the outer surface of the composite BOPP film, which is dried at 90°C, and then water-based color ink (commonly used in the market) is used to print the outer surface of the composite BOPP film, which is dried at 50°C, and thus the printed color film is obtained.

[0049] At the same time, the inner surface of the composite BOPP film is treated by 50 kV and 10 kHz corona treatment, and then the surface modification coating agent is sprayed to coat the outer surface of the composite BOPP film, which is dried at 90°C.

[0050] The printed color film obtained in Example 1 is tested for gloss and light transmittance, and the results are shown in Table 2 below:

[0051] Table 2 Test results of the printed color film obtained in Example 2

[0052] Machine suitability, same as Example 1.

[0053] Example 3: Method for improving the gloss of printed color film (micro-shrink film).

[0054] The three layers of the composite BOPP film are as follows: the surface layer is a blended film with the content of copolymerized PP, 0.05 wt% of silicon dioxide, 0.05 wt% of phenyl-modified silicone and 4.0 wt% of hydrogenated petroleum resin; the core layer is a blended film of homopolymerized PP, 0.40 wt% of antistatic agent (the mass ratio of alkyl diethanolamine and monoglyceride is 1:0.3) and 10.0 wt% of hydrogenated petroleum resin; and the inner layer is a blended film with the content of copolymerized PP, 0.15 wt% of phenyl-modified silicone and 1.5 wt% of hydrogenated petroleum resin;

[0055] The modified coating agent composition and preparation method are as follows: the mass ratio of water-based silane coupling agent (amino silane), tetraethyl orthosilicate, solid acid (ethylenediaminetetraacetic acid) and water is 10:50:10:400. Amino silane 10 g and ethylenediaminetetraacetic acid 10 g are added into 400 g (ml) of water to be mixed and dissolved, and then tetraethyl orthosilicate 50 g is added drop by drop at 3000 rpm, and after the dropwise addition is completed, stirring is continued for 10 min; thus a transparent slightly viscous surface modification coating agent is obtained;

[0056] The outer surface of the composite BOPP film is pretreated by CO2 low-temperature plasma surface activation treatment; then the surface modification coating agent is sprayed to coat the outer surface of the composite BOPP film, and after drying at 90℃, the outer surface of the composite BOPP film is printed using water-based color ink (commonly used in the market), and after drying at 50℃, the printed color film is obtained;

[0057] Meanwhile, the inner surface of the composite BOPP film is treated by 50 kV and 10 kHz corona treatment, and then the surface modification coating agent is sprayed to coat the outer surface of the composite BOPP film, and drying is carried out at 90℃;

[0058] The same as in Example 1, the printed color film obtained is tested for glossiness and light transmittance, and the results are shown in Table 3 below:

[0059] Table 3 Test results of the printed color film obtained in Example 3

[0060] The same as in Example 1.

[0061] Finally, it should be pointed out that the above preferred embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present application.

Claims

1. A method of improving the gloss ink color fastness of a printed color film, characterized by, The printed color film is a composite BOPP film, and the method comprises the following steps: (1) pretreating the outer surface and the inner surface of the composite BOPP film; (2) coating the outer surface and the inner surface of the composite BOPP film with a surface modification coating agent, and drying at high temperature; (3) printing the outer surface of the composite BOPP film with water-based color ink, and obtaining the printed color film after drying.

2. The method of claim 1, wherein, The composite BOPP film is three-layered, the surface layer is a blended film of copolymerized PP and silicon dioxide, phenyl-modified silicone and hydrogenated petroleum resin; the core layer is a blended film of homopolymerized PP and antistatic agent and hydrogenated petroleum resin; and the inner layer is a blended film of copolymerized PP and phenyl-modified silicone and hydrogenated petroleum resin. The content of silicon dioxide in the surface layer is not higher than 0.08wt%, the content of phenyl-modified silicone is 0.05-0.10wt%, and the content of hydrogenated petroleum resin is 3.0-5.0wt%; the antistatic agent in the core layer is a mixture of alkyl diethanolamine and monoglyceride, the content of the antistatic agent is 0.35%-0.45wt%, and the content of hydrogenated petroleum resin is 10.0-15.0wt%; and the content of phenyl-modified silicone in the inner layer is 0.10-0.20wt%, and the content of hydrogenated petroleum resin is 1.0-2.0wt%.

3. The method of claim 2, wherein, In step (1), the outer surface of the composite BOPP film is pretreated by low-temperature plasma surface activation treatment, and the gas used is CO2; and the inner surface of the composite BOPP film is treated by corona treatment, the voltage of the corona treatment is 10-20kV, and the frequency is 2-5kHz.

4. The method of claim 1, wherein, The surface modification coating agent in step (2) comprises water-based silane coupling agent, tetraethyl orthosilicate, solid acid and water, and the mass ratio is (5-10):(50-100):(5-10):(300-400).

5. The method of claim 1, wherein, The water-based silane coupling agent is one of methyltrichlorosilane (MTS) or amino silane; and the solid acid is ethylenediaminetetraacetic acid.

6. The method of claim 5, wherein, The preparation of the surface modification coating agent comprises the following steps: dissolving the water-based silane coupling agent and the solid acid in water, then adding the tetraethyl orthosilicate drop by drop under high-speed stirring, and obtaining the surface modification coating agent after the reaction is completed.

7. The method of claim 5, wherein, The coating of the surface modification coating agent in step (2) adopts spraying; and the drying temperature is 80-100℃.

8. The method of claim 1, wherein, The drying temperature after printing in step (3) is 40-50℃.

9. The method of claim 1, wherein, 10. The use of the high-printed color film obtained by the method according to any one of claims 1-9 for improving the gloss and ink color fastness of the printed color film for tobacco packaging film. ​

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