A dyeing method for PET aluminum-coated film

Abstract

This invention discloses a dyeing method for a PET aluminized film, which exhibits high color fastness and good steam resistance. The dyeing method for a PET aluminized film includes the following steps: Step (1), etching the PET aluminized film using tetramethylammonium hydroxide; Step (2), dyeing the PET aluminized film obtained in step (1) using an acidic medium dye; Step (3), fixing the color of the PET aluminized film obtained in step (2) using a color-fixing agent; Step (4), surface treating the PET aluminized film obtained in step (3) using a coating agent, followed by drying.

Description

Technical Field

[0001] This invention belongs to the field of PET metallized film technology, specifically relating to a dyeing method for PET metallized film, which is used to produce gold and silver wires with a strong black color. Background Technology

[0002] Aluminized polyester (PET) film is a composite film of PET film and metallic aluminum. It is a barrier film formed by depositing aluminum atoms onto the PET film through vacuum aluminizing processes such as evaporation, sputtering, and ion plating (Reference: Polymer Materials Science and Engineering, 2017, 33(03), 64-70). One important application of aluminized PET film is the production of polyester metallic threads. Polyester metallic threads are made by further coating a resin protective layer onto the aluminized PET film, followed by slitting and longitudinal micro-cutting into flat metallic threads with a rectangular cross-section (Reference: FZ / T63026-2015). Using metallic threads on fabrics can make the fabric unique, sparkling, fashionable, elegant, and high-end, thereby improving the product grade and increasing the added value of the product (Reference: Wool Textile Technology, 2013, 41(06), 16-18).

[0003] The color of polyester gold and silver wire is usually obtained by adding dyes or pigments to the resin when coating the aluminum film (Reference: Liao Qixia, Guangzhou Chemical Industry, 2013, 41(24), 196-197+201). There is no interaction between the dyes or pigments and the aluminum film, and they rely entirely on the resin to adhere to the surface of the aluminum film.

[0004] Existing technologies suffer from at least the following problems: the color fastness of polyester gold and silver threads or aluminized films is not high enough, resulting in poor resistance to steam and insufficient resistance to light. This phenomenon is particularly prominent in black products. Summary of the Invention

[0005] In view of the shortcomings of the above-mentioned background technology, the purpose of this invention is to provide a dyeing method for PET aluminized film, which has high black color fastness, good steam resistance and sufficient light resistance.

[0006] To solve the above-mentioned technical problems, the objective of this invention is achieved as follows:

[0007] A dyeing method for a PET metallized film includes the following steps:

[0008] Step (1): The PET aluminized film is etched using tetramethylammonium hydroxide;

[0009] Step (2): The PET aluminized film obtained in step (1) is dyed with an acidic mordant dye;

[0010] Step (3): Fix the PET aluminized film obtained in step (2) with a color-fixing agent;

[0011] Step (4): Apply a coating agent to the surface of the PET aluminized film obtained in step (3) and dry it.

[0012] Based on the above scheme and as the preferred scheme, the etching method in step (1) is as follows:

[0013] The PET aluminized film was immersed in an aqueous solution of tetramethylammonium hydroxide for etching, and then rinsed with deionized water. The mass concentration of the aqueous solution of tetramethylammonium hydroxide was 2% to 6%. The temperature of the aqueous solution of tetramethylammonium hydroxide was 40°C. The etching time was 30 seconds. The rinsing time was 10 seconds.

[0014] Based on the above scheme and as a preferred option, the staining method in step (2) is as follows:

[0015] The PET aluminized film obtained in step (1) is immersed in an aqueous solution of acidic mordant dye for dyeing, and then rinsed with deionized water. The acidic mordant dye comprises a dye composition of 35% CI mordant black 106, 50% CI mordant black 52, 10% CI mordant orange 3 and 5% CI mordant red 74. The concentration of the aqueous solution of the acidic mordant dye is 1 g / L to 10 g / L. The pH of the aqueous solution of the acidic mordant dye is 5.5. The temperature of the aqueous solution of the acidic mordant dye is 40°C. The dyeing time is 0.5 min to 5 min. The rinsing time is 10 s.

[0016] Based on the above scheme and as a preferred option, the color-fixing method in step (3) is as follows:

[0017] The PET aluminized film obtained in step (2) is immersed in an aqueous solution of a color-fixing agent for color fixing; the color-fixing agent is a cationic color-fixing agent TF-232; the mass concentration of the aqueous solution of the color-fixing agent is 5%; the temperature of the aqueous solution of the color-fixing agent is 25℃; and the color fixing time is 30s.

[0018] Based on the above scheme and as a preferred embodiment of the above scheme: the surface treatment method in step (4) is as follows:

[0019] The PET aluminized film obtained in step (3) is immersed in the aqueous solution of the coating agent, taken out, immersed again, taken out again, and dried. The coating agent formula includes 6% waterborne epoxy resin, 6% waterborne epoxy resin curing agent, 11% acrylic resin, and 77% water. The working temperature of the aqueous solution of the coating agent is 25°C. The immersion time is 5 seconds each time. The drying temperature is 180°C. The drying time is 10 minutes.

[0020] The outstanding and beneficial technical effects of this invention compared to the prior art are:

[0021] The dual-purpose transport vehicle of the present invention, compared with the prior art,

[0022] This invention first etches the aluminum plating layer to create a microporous structure that can accommodate dye molecules. Then, a selected acidic medium dye is used for dyeing. The dye can enter the micropores of the aluminum plating layer and chelate with aluminum atoms, thereby giving the dye molecules an affinity for the aluminum plating film. Next, a fixing agent is used to seal the anions on the dye molecules, further reducing the possibility of dye molecules falling off. Finally, a coating agent is used to completely seal the dye molecules in the aluminum plating layer of the aluminum film.

[0023] In existing metallized film coloring technologies, dyes or pigments must rely on adhesives to adhere to the surface of the metallized film, resulting in no direct contact between the dye or pigment and the metallized film. In this invention, the dye not only directly contacts the metallized layer but also exhibits an affinity for it. Specifically, the acidic medium dye selected in this invention can penetrate the micropores of the metallized layer and chelate with aluminum atoms, thereby allowing the dye molecules themselves to firmly bind to the metallized layer.

[0024] Through long-term production and experimentation, the inventors discovered that using the black acidic mordant dye composition and corresponding dyeing method for PET metallized films provided by this invention can achieve a stable and durable black color in PET metallized films. The components of the black acidic mordant dye composition of this invention are all commercially available conventional dyes. The dye components have high structural similarity, similar molecular weights, and good dyeing compatibility. The dye composition exhibits good color reproducibility, simple dyeing operation, and good lightfastness.

[0025] This invention also uses a fixing agent to fix the color after dyeing. Specifically, this invention uses a cationic fixing agent to eliminate the anionic charge of the acidic mordant dye, reduce the hydrophilicity of the dye, and allow the dye to be further fixed to the aluminum plating layer. The fixing agent of this invention is a commercially available conventional cationic fixing agent, which is inexpensive and simple to use.

[0026] Finally, the present invention further uses a coating adhesive to seal the colored aluminized film after dyeing and fixing, which can further prevent dye molecules from falling off the surface of the aluminized film. All components of the coating adhesive of the present invention are commercially available conventional products, inexpensive, and simple to use for surface treatment.

[0027] In this invention, although etching the aluminum coating layer, dyeing aluminum products with acidic medium dyes, fixing acidic dyes with cationic fixing agents, and surface treatment of the aluminum coating film with coating agents are conventional approaches in the fields of aluminum etching, aluminum product dyeing, acidic dye fixing, and aluminum coating film surface treatment, respectively, no method has yet been found that combines these approaches to obtain a stable and durable black PET aluminum coating film for polyester gold and silver wire.

[0028] Furthermore, the aluminum etching process, aluminum product dyeing process, dye fixing process, and aluminum film surface treatment process used in this invention all need to be improved in order to obtain the stable and durable black PET aluminum film specific to this invention. The black PET aluminum film obtained by this invention has superior color fastness compared to existing products, and has broad application prospects, especially in the field of polyester gold and silver yarn. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a dyed PET aluminized film.

[0030] Figure reference numerals: PET substrate 01; metallized layer, dye, fixing agent 02; coating agent 03; Detailed Implementation

[0031] The present invention will now be described in detail and specifically through specific embodiments, with reference to the accompanying drawings, to provide a better understanding of the invention. However, the following embodiments do not limit the scope of the invention. (Appendix) Figure 1 This is a schematic diagram of the structure of a dyed PET aluminized film.

[0032] The metallized PET film uses commercially available double-sided metallized PET film material. The PET substrate thickness is 0.012–0.015 mm, and the metallized layer thickness is 0.6–0.8 μm. The tetramethylammonium hydroxide, acidic mordant dyes, fixing agents, adhesives, and other related chemicals used are all commercially available products.

[0033] Example 1

[0034] Perform the following steps in sequence:

[0035] 1) Immerse the commercially available PET aluminized film in an aqueous solution of tetramethylammonium hydroxide at a temperature of 40°C and a mass concentration of 2% for 30 seconds, then remove it and rinse it with deionized water for 10 seconds to remove the residual etching solution.

[0036] 2) Weigh CI mordant black 106 (7g, 35 wt%), CI mordant black 52 (10g, 50 wt%), CI mordant orange 3 (2g, 10 wt%), and CI mordant red 74 (1g, 5 wt%) as an acidic mordant dye composition for black, dissolve in deionized water (15L), adjust the pH to 5.5 with acetic acid, add sodium acetate (200g) as a pH stabilizer, and then add deionized water until the total volume of the dye solution reaches 20L. At this point, the concentration of the dye solution is 1g / L. Immerse the PET aluminized film obtained in step (1) in an aqueous solution of acidic mordant dye at a temperature of 40℃, keep it for 0.5min, then remove it and rinse it with deionized water for 10s. The purpose of rinsing is to wash away the dye on the surface of the aluminized film that has not entered the membrane pores.

[0037] 3) Immerse the PET aluminized film obtained in step (2) in an aqueous solution of TF-232 fixing agent at a temperature of 25℃ and a mass concentration of 2%, and remove it after 30s.

[0038] 4) Prepare an aqueous solution of coating agent with 6% waterborne epoxy resin, 6% waterborne epoxy resin curing agent, 11% acrylic resin and 77% water; immerse the PET aluminized film obtained in step (3) into the aqueous solution of coating agent at a temperature of 25°C for 5 seconds, take it out, immerse it again for 5 seconds, take it out, and dry it in an oven at 180°C.

[0039]

[0040] Test 1: Color Deviation Test

[0041] The 50 pieces of black PET aluminized film obtained in Example 1 were tested with a colorimeter and compared with the standard color chart (JJG453-2002 Standard Color Chart Verification Procedure) to obtain the color difference ΔE. If ΔE < 1, it is qualified.

[0042] Test 2: High-Temperature Steam Test

[0043] Cut 50 2cm x 2cm squares from the obtained black PET metallized film (only products that pass Test 1 are tested; any products that fail Test 1 must be discarded). Place these squares in a 5L steam boiler containing 1L of water and heat to 110℃ for 30 minutes. Then, remove the metallized film when the temperature drops below 60℃. Visually inspect the metallized film under a standard light source (D65, color temperature 6500K, power 18W) for any color changes (fading, discoloration, or unevenness). A metallized film color matching the black hue on the standard color chart is acceptable; a color deviating from the black hue on the standard color chart is unacceptable.

[0044] Test 3: Sun Resistance Test

[0045] Place 50 pieces of black PET aluminized film (only test the qualified finished products in Test 1, that is, if there are unqualified products detected in Test 1, the unqualified products need to be removed) under a standard xenon lamp and expose them for 24 hours. Then, under a standard light source (D65, color temperature 6500K, power 18W), compare the color of the aluminized film with the black color light on the standard color plate. If the color of the aluminized film conforms to the black color light on the standard color plate, it is qualified; if the color of the aluminum part deviates from the black color light on the standard color plate, it is unqualified.

[0046] Test results: The pass rate of the color difference test of the black PET aluminized film obtained in Example 1 is 100%, the pass rate of the high-temperature steam test is 100%, and the pass rate of the sun resistance test is 100%.

[0047] Examples 2 - 5

[0048] Replace the concentration of the aqueous solution of tetramethylammonium hydroxide in step (1) of Example 1 with 3% - 6%, and the others are the same as in Example 1. The results are shown in Table 1.

[0049] Table 1

[0050]

[0051] As can be seen from Table 1, under the action of the aqueous solution of tetramethylammonium hydroxide with a specific concentration provided in the present invention, the finally obtained black PET aluminized film all has good color fastness.

[0052] Examples 6 - 10

[0053] Replace the dyeing time in step (2) of Example 1 with 1 min - 5 min, and the others are the same as in Example 1. The results are shown in Table 3.

[0054] Table 2

[0055]

[0056] As can be seen from Table 3, when the dyeing time is 1 min - 5 min in step (2) of the present invention, the obtained black PET aluminized film all has good color fastness.

[0057] Comparative Example 1

[0058] Omit step (1) in Example 1 and directly perform steps (2) - (4), and the others are the same as in Example 1. That is, in the preparation method of the black PET aluminized film of the present invention, do not perform etching treatment on the PET aluminized film, and directly perform dyeing, fixing and surface treatment operations. Result: The PET aluminized film has no color.

[0059] This is because the surface of the PET aluminized film is smooth, and dye molecules cannot be adsorbed onto the aluminized layer, resulting in the inability to color the film.

[0060] Comparative Examples 2-5

[0061] The concentration of the aqueous solution of tetramethylammonium hydroxide in step (1) of Example 1 was changed to 0.1%–0.5% or 10%–20%, while other aspects remained the same as described in Example 1. The results are shown in Table 3.

[0062] Table 3

[0063]

[0064] In Comparative Example 2, the concentration of tetramethylammonium hydroxide aqueous solution was low, resulting in poor etching ability of the aluminum plating layer. Dye molecules could not be adsorbed onto the aluminum plating layer, ultimately leading to the inability to apply color.

[0065] In Comparative Example 3, the concentration of tetramethylammonium hydroxide aqueous solution was low, resulting in insufficient etching of the aluminum plating layer, inadequate adsorption of dye molecules, a lighter color, and a larger color difference. Due to insufficient dye adsorption, the lightfastness of the dyed parts deteriorated.

[0066] In Comparative Example 4, the concentration of tetramethylammonium hydroxide aqueous solution was too high, and the etching degree of the aluminum plating layer was too severe. This resulted in fewer sites for dye adsorption, a decrease in the amount of dye adsorbed, a lighter color, a greater color difference, and poorer lightfastness.

[0067] In Comparative Example 5, the high concentration of tetramethylammonium hydroxide aqueous solution caused severe corrosion of the aluminum plating layer, resulting in less dye adsorption and a very light color. At the same time, the gloss of the aluminum plating film was severely damaged, leading to a large color difference. Due to the light color, the light-light resistance was also very poor.

[0068] Comparative Example 6

[0069] Replace the tetramethylammonium hydroxide in step (1) of Example 1 with sodium hydroxide or potassium hydroxide, and otherwise follow the same procedure as in Example 1.

[0070] Result: The color difference test pass rate was 38%. This is because, under the same conditions, aqueous solutions of sodium hydroxide and potassium hydroxide exhibit stronger alkalinity, leading to severe corrosion of the aluminum plating layer. Ultimately, the metallic luster of the aluminum plating film is severely damaged, resulting in a dull luster and a significant decrease in the color difference test pass rate.

[0071] The steam test pass rate was 100%. This is because the dye is firmly sealed inside and will not escape from the aluminum coating.

[0072] The pass rate for the sun resistance test was 100%. This is because the dye composition itself has excellent sun resistance, and the components were not changed in this example; therefore, it has excellent sun resistance.

[0073] Comparative Example 7

[0074] The black acid mordant dye composition in step (2) of Example 1 was replaced with CI Mordant Black 106 (4g, 20% by weight), CI Mordant Black 52 (14g, 70% by weight), CI Mordant Orange 3 (1g, 5% by weight) and CI Mordant Red 74 (1g, 5% by weight). That is, the types of components remained the same, but the content of the components changed. Other aspects are the same as in Example 1.

[0075] Result: The color difference test pass rate of the obtained black PET metallized film was 0. This is because changing the component ratio in the black dye composition of this invention caused a change in color, making it impossible to obtain the desired black color.

[0076] Comparative Example 8

[0077] The black acid mordant dye composition in step (2) of Example 1 was changed to CI Mordant Black 106 (7g, 50% by weight) and CI Mordant Black 52 (10g, 50% by weight), that is, the composition of the black dye composition was changed, and the rest was the same as in Example 1.

[0078] As a result, the color difference test pass rate of the obtained black PET metallized film was 0. This is because changing the types of components in the black dye composition of this invention caused a change in color, making it impossible to obtain the desired black color.

[0079] Comparative Example 9

[0080] The black acid mordant dye composition in step (2) of Example 1 was replaced with CI Mordant Black 19 (7g, 35% by weight), CI Mordant Black 15 (10g, 50% by weight), CI Mordant Orange 3 (2g, 10% by weight), and CI Mordant Red 34 (1g, 5% by weight). In this example, CI Mordant Black 19, which has a similar structure and color, was used instead of Black 106, CI Mordant Black 15 was used instead of CI Mordant Black 52, CI Mordant Red 34 was used instead of CI Mordant Red 74, and CI Mordant Orange 15 was used instead of CI Mordant Orange 3. Other aspects are the same as in Example 1.

[0081] Results: The color difference test pass rate of the obtained black PET aluminized film was 70%. This result indicates that even slight changes in dye structure and chroma can still lead to some color difference variation. The steam test pass rate of the obtained black PET aluminized film was 100%. This is because the dye was firmly sealed inside and did not escape from the aluminized film. The lightfastness test pass rate of the obtained black PET aluminized film was 0%. This is because the dye selected in this example had poor lightfastness, resulting in the final dyed sample failing the lightfastness test.

[0082] Comparative Example 10

[0083] Step (3) in Example 1 is omitted, and steps (1), (2) and (4) are performed directly, with the rest as in Example 1. That is, in the preparation method of the black PET aluminized film of the present invention, the dyed PET aluminized film is not subjected to color fixing treatment, but only etching, dyeing and surface treatment operations are performed.

[0084] Results: The color difference test pass rate of the obtained black PET aluminized film was 98%. The steam test pass rate was 70%. This is because: without a fixing agent to fix the dye, a small amount of dye may still pass through the coating and leave the aluminized film under steam conditions.

[0085] Comparative Example 11

[0086] Step (4) in Example 1 is omitted, and steps (1)-(3) are performed directly, with the rest as in Example 1. That is, in the preparation method of the black PET aluminized film of the present invention, the surface treatment of the dyed aluminized film is not performed, only etching, dyeing and fixing operations are performed. Result: The color difference test pass rate of the obtained black PET aluminized film is 96%. The steam test pass rate is 0. This is because without the protection of the coating, the dye is easily destroyed by steam.

[0087] Comparative Example 12

[0088] An existing technology involves mixing colorant, binder, and solvent to formulate a coating, which is then applied to an aluminized film to color the film. This technology uses commercially available disperse dye filter cake (a hydrophobic dye) as the colorant, acrylic resin and polyurethane resin as binders, and xylene and ethanol as solvents. The specific formulation of the coating is: 4% commercially available disperse black ECT filter cake (obtained by compounding disperse orange 288, disperse violet 93:1, disperse blue 291:3, and disperse orange 30:2), 15% acrylic resin, 6% polyurethane resin, 55% xylene, and 20% ethanol. The coating process is as follows:

[0089] The coating was evenly applied to the aluminized film, and the squeegee position was adjusted to ensure the coating thickness did not exceed 5 μm. The coated aluminized film was then placed in a 180℃ oven and baked for 10 minutes, followed by cooling. Results: The steam test pass rate for the obtained black aluminized film was 34%. This is because the existing technology relies solely on the adhesive to fix the dye to the aluminized film, resulting in insufficient adhesion and severe damage to most test pieces under steam conditions. The lightfastness test pass rate for the obtained black aluminized film was 42%. Commercially available disperse black ECT coatings showed color changes in some test pieces when exposed to strong light on the coated aluminized film.

[0090] The test results of the above embodiments and comparative examples show that the dyeing method provided by the present invention can obtain qualified black PET aluminized film with stable product quality and good resistance to steam and sun exposure.

[0091] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for dyeing a PET aluminized film, characterized in that: Includes the following steps: Step (1) involves etching the PET aluminized film using tetramethylammonium hydroxide; the etching method in step (1) is as follows: The PET aluminized film was immersed in an aqueous solution of tetramethylammonium hydroxide for etching, and then rinsed with deionized water. The mass concentration of the aqueous solution of tetramethylammonium hydroxide was 2%~6%; the temperature of the aqueous solution of tetramethylammonium hydroxide was 40℃; and the etching time was 30s. Step (2) involves dyeing the PET aluminized film obtained in step (1) with an acidic mordant dye; the dyeing method in step (2) is as follows: The PET aluminized film obtained in step (1) is immersed in an aqueous solution of acidic mordant dye for dyeing, and then rinsed with deionized water. The acidic mordant dye comprises a dye composition of 35% CI mordant black 106, 50% CI mordant black 52, 10% CI mordant orange 3 and 5% CI mordant red 74. The concentration of the aqueous solution of the acidic mordant dye is 1 g / L to 10 g / L. The pH of the aqueous solution of the acidic mordant dye is 5.

5. The temperature of the aqueous solution of the acidic mordant dye is 40°C. Step (3) involves fixing the PET aluminized film obtained in step (2) with a color-fixing agent; the color-fixing method described in step (3) is as follows: The PET aluminized film obtained in step (2) is immersed in an aqueous solution of a fixing agent for fixing; the fixing agent is a cationic fixing agent; Step (4): Apply a coating agent to the surface of the PET aluminized film obtained in step (3), and then dry it. The surface treatment method described in step (4) is as follows: Immerse the PET aluminized film obtained in step (3) into the aqueous solution of the coating agent, take it out, immerse it again, take it out again, and dry it. The coating agent formula includes 6% waterborne epoxy resin, 6% waterborne epoxy resin curing agent, 11% acrylic resin, and 77% water.

2. The dyeing method for PET aluminized film according to claim 1, characterized in that: The rinsing time in step (1) is 10 seconds.

3. The dyeing method for PET aluminized film according to claim 1, characterized in that: The staining time in step (2) is 0.5 min to 5 min; the rinsing time in step (2) is 10 s.

4. The dyeing method for PET aluminized film according to claim 1, characterized in that: In step (3), a cationic fixing agent TF-232 is used; the mass concentration of the aqueous solution of the fixing agent is 5%; the temperature of the aqueous solution of the fixing agent is 25℃; and the fixing time is 30s.

5. The dyeing method for PET aluminized film according to claim 1, characterized in that: The aqueous solution of the coating agent in step (4) is used at a temperature of 25°C; the immersion time is 5 seconds each time; the drying temperature is 180°C; and the drying time is 10 minutes.

Images