A manufacturing process for hot stamping foil specifically for biodegradable cigarette tipping paper

Abstract

This invention relates to a process for manufacturing hot stamping foil for cigarette tipping paper. The process involves preparing a base film layer, release layer, color layer, plating layer, and adhesive layer using biodegradable materials. The base film is prepared by mixing polylactic acid with a cellulose derivative. A wax-based release agent is then coated onto the base film to form the release layer. Next, a water-based pigment is coated to form the color layer. A thin aluminum plating layer is formed using vacuum evaporation. Finally, a biodegradable adhesive is coated to form the adhesive layer. The hot stamping foil obtained by this process is suitable for cigarette tipping paper, possessing certain degradation properties and hot stamping adhesion. The manufacturing process includes raw material preparation, coating, and drying steps, and is applicable to the cigarette packaging industry.

Description

Technical Field

[0001] This invention relates to the field of material degradation technology, specifically to a manufacturing process for a biodegradable hot stamping foil for cigarette tipping paper. Background Technology

[0002] Cigarette tipping paper is used in cigarette production to connect filters and cigarettes, and is often hot-stamped to enhance appearance and brand recognition. Traditional hot-stamping foil typically uses polyester or polypropylene as the base material. These petroleum-based polymers provide mechanical support and gloss during the hot-stamping process, but they are difficult to decompose in the environment after disposal, leading to the accumulation of plastic waste and potential soil and water pollution. With the strengthening of environmental regulations and the cigarette industry's demand for sustainable development, the development of biodegradable hot-stamping foil has become a trend. Existing hot-stamping foil manufacturing processes focus on hot-stamping durability, gloss, and adhesion. For example, some methods use chemically synthesized release agents and solvent-based color layers to ensure transfer performance under high temperature and pressure. However, these components often contain volatile organic compounds, increasing the environmental burden during the production process.

[0003] For example, in existing production methods, polyethylene terephthalate (PET) is often used as a carrier for the base film layer. Hot stamping separation is achieved by coating with synthetic wax or a silicone-based release layer, followed by the addition of a pigment layer and a metallic coating, and finally a hot melt adhesive layer. This structure provides metallic luster and pattern clarity in cigarette tipping paper applications, but the overall material is difficult to decompose under natural conditions. Some processes that attempt to introduce water-based coatings reduce solvent use, but the base film still relies on non-bio-based materials, resulting in limited degradation performance and failing to meet the requirements for rapid decomposition of cigarette waste. Furthermore, in the specific application scenarios of cigarette tipping paper, hot stamping foil needs to possess moisture resistance, abrasion resistance, and compatibility with the paper base. Existing biodegradable materials, such as single polylactic acid films, lack flexibility and adhesion, easily leading to cracks or uneven transfer during the hot stamping process.

[0004] Furthermore, while existing low-temperature hot stamping technologies optimize energy consumption, they are mostly designed for non-degradable materials and cannot be directly applied to biodegradable systems. Some environmentally friendly tipping paper processes involve transferring an aluminum plating layer, but the plating thickness is relatively thick, affecting the degradation rate, and the overall biodegradability of the hot stamping foil is not taken into account.

[0005] Therefore, there is a need for a hot stamping foil manufacturing process for cigarette tipping paper that can achieve degradation performance while maintaining hot stamping stability and gloss effect by selecting bio-based material combinations and optimizing interlayer structure, so as to meet the environmental transformation needs of the cigarette industry. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problems existing in the prior art, the inventors have proposed the present invention.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a manufacturing process for biodegradable hot stamping foil for cigarette tipping paper.

[0009] This invention provides a manufacturing process for biodegradable hot stamping foil for cigarette tipping paper. This process achieves the environmentally friendly characteristics of the hot stamping foil by selecting bio-based materials and optimizing coating parameters, while maintaining the hot stamping effect.

[0010] The process includes the following steps: (1) Preparation of base film: Polylactic acid and hydroxypropyl cellulose are mixed at a mass ratio of 1:0.2 to 1:0.5, solvent is added and stirred evenly, and the mixture is extruded to form a film with a thickness of 15-25 micrometers.

[0011] (2) Release layer coating: Beeswax and vegetable oil are mixed at a mass ratio of 1:0.1 to 1:0.3, heated and melted, and then coated on the surface of the base film layer. After drying, a release layer with a thickness of 1-3 micrometers is formed.

[0012] (3) Color coating: Mix water-soluble pigments with polyvinyl alcohol at a mass ratio of 1:0.5 to 1:1, coat the mixture onto the surface of the release layer, and dry to form a color layer with a thickness of 2-4 micrometers.

[0013] (4) Coating formation: Aluminum is deposited on the surface of the color layer by vacuum evaporation to form a coating with a thickness of 0.02-0.05 micrometers.

[0014] (5) Coating the adhesive layer: Mix gelatin and glycerin at a mass ratio of 1:0.1 to 1:0.3, coat the coating on the surface of the coating, and after drying, form an adhesive layer with a thickness of 3-5 micrometers to obtain hot stamping foil.

[0015] In this process, each layer of material uses biologically derived components, which helps the hot stamping foil decompose naturally after use. Polylactic acid, as the main component of the base film, provides mechanical strength; the beeswax release layer facilitates hot stamping transfer; the water-based color layer ensures uniform color; the thin aluminum coating imparts a metallic luster; and the gelatin layer enhances its adhesion to cigarette tipping paper.

[0016] The beneficial effects of this invention are as follows: the hot stamping foil obtained by this process exhibits suitable adhesion and gloss when hot stamped onto cigarette tipping paper. At the same time, the material combination allows for gradual decomposition in soil or aquatic environments, reducing long-term environmental impact. Through the mixing of polylactic acid and hydroxypropyl cellulose, the base film layer achieves a balanced flexibility and degradation rate, facilitating hot stamping operations on cigarette production lines and avoiding the waste problems caused by traditional non-degradable base films. The combination of beeswax and vegetable oil in the release layer provides a smooth separation surface, supports low-temperature hot stamping, reduces energy consumption, and is more environmentally friendly compared to existing high-temperature processes.

[0017] Compared to traditional processes, this method simplifies raw material selection, avoids complex synthesis steps, and facilitates industrial production. In addition, by adjusting the proportions of each layer, such as increasing hydroxypropyl cellulose to improve the flexibility of the base film, or optimizing the beeswax ratio to improve transfer efficiency, this process allows for parameter optimization based on the specific humidity tolerance requirements of cigarette tipping paper, achieving a balance between degradation rate and performance. This solution draws on existing hot stamping foil coating technology but incorporates biodegradable materials, enhancing the sustainability of cigarette packaging. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0019] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0020] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0021] Example 1 This embodiment provides a manufacturing process for biodegradable hot stamping foil for cigarette tipping paper.

[0022] Specifically, take 100 grams of polylactic acid and 20 grams of hydroxypropyl cellulose, add 200 ml of ethyl acetate as a solvent, and stir in a mixer at 300 rpm for 30 minutes until the mixture is uniform and free of particles.

[0023] The mixture was extruded into a film using an extruder, with the extrusion temperature controlled at 180 degrees Celsius and the extrusion speed at 2 meters per minute. After cooling, a base film layer with a thickness of about 15 micrometers was obtained.

[0024] The base film has a smooth surface and moderate flexibility, which facilitates subsequent coating.

[0025] Next, take 50 grams of beeswax and 5 grams of vegetable oil, heat them in a pot to 70 degrees Celsius to melt them, stir for 10 minutes until uniform, and then use a coating machine to evenly coat the base film surface at a coating speed of 5 meters / minute, controlling the coating amount to 2 grams per square meter. Then, dry it in a drying oven at 60 degrees Celsius for 20 minutes to form a release layer with a thickness of about 1 micrometer.

[0026] This release layer provides a smooth surface, which helps with separation during hot stamping.

[0027] Then, take 30 grams of water-soluble pigment and 15 grams of polyvinyl alcohol, add 100 ml of water and stir in a mixer for 15 minutes to dissolve. Use a coating machine to coat the surface of the release layer at a coating speed of 4 meters / minute and a coating amount of 3 grams per square meter. Dry in a drying oven at 50 degrees Celsius for 15 minutes to form a color layer with a thickness of about 2 micrometers. The color layer has a uniform color and no bubble defects.

[0028] Aluminum is deposited on the surface of the color layer using a vacuum evaporation machine. The vacuum level is 10^-4 Pa, the evaporation time is 5 minutes, and the aluminum source temperature is controlled at 1400 degrees Celsius. This results in a coating with a thickness of about 0.02 micrometers, which has a uniform luster and provides a metallic effect.

[0029] Finally, take 40 grams of gelatin and 4 grams of glycerin, add 80 ml of water and stir for 20 minutes to dissolve. Use a coating machine to coat the coating surface at a speed of 3 meters / minute and a coating amount of 4 grams per square meter. Dry in a drying oven at 40 degrees Celsius for 10 minutes to form a glue layer with a thickness of about 3 micrometers, thus obtaining the hot stamping foil product.

[0030] The hot stamping foil obtained in this embodiment was used for hot stamping tests on cigarette tipping paper: It was hot stamped for 5 seconds at 150 degrees Celsius and 2 MPa pressure on a hot stamping machine. The hot stamping pattern was observed to be completely transferred to the paper base, with a uniform surface gloss and no peeling. Adhesion tests showed that the peel force was 1.5 N / cm in a standard tensile test.

[0031] After being placed in a simulated soil environment for 90 days, the hot stamping foil lost approximately 20% of its mass, indicating that the organic layer began to decompose. In the flexibility test, the base film showed no cracks after 10 bends. Compared with traditional non-degradable hot stamping foil, this product has comparable adhesion but superior degradation performance. By selecting the ratio of polylactic acid to hydroxypropyl cellulose, the base film layer has moderate strength, facilitating the coating process.

[0032] The sequence of these process steps ensures a tight bond between the layers, preventing peeling issues. Test data shows that this degradation rate is suitable for the cigarette's lifespan, avoiding premature decomposition that could affect pattern stability.

[0033] Example 2 This embodiment provides a manufacturing process for biodegradable hot stamping foil for cigarette tipping paper.

[0034] Specifically, 100 grams of polylactic acid and 30 grams of hydroxypropyl cellulose were added to 250 ml of ethyl acetate. The mixture was stirred in a mixer at 400 rpm for 40 minutes until completely dissolved. The solution was then extruded into a film at 190 degrees Celsius and a speed of 2.5 m / min to obtain a base film layer with a thickness of approximately 18 micrometers. This base film layer has a uniform thickness, a flawless surface, and improved overall mechanical properties.

[0035] Further, take 50 grams of beeswax and 10 grams of vegetable oil, heat to 75 degrees Celsius to melt, stir for 15 minutes and then apply to the base film layer at a speed of 6 meters / minute, with a coating amount of 2.5 grams per square meter. Dry in a drying oven at 60 degrees Celsius for 25 minutes to form a release layer with a thickness of about 1.5 micrometers.

[0036] The release layer has a moderate thickness, which improves the transfer efficiency.

[0037] Take 30 grams of water-soluble pigment, 20 grams of polyvinyl alcohol, and 120 ml of water, stir for 20 minutes, apply at a speed of 5 meters per minute, apply 3.5 grams per square meter, and dry at 50 degrees Celsius for 15 minutes to form a color layer with a thickness of about 2.5 micrometers. This color layer is firmly adhered and has saturated color.

[0038] Vacuum evaporation of aluminum, with a vacuum degree of 10^-4 Pa, a time of 6 minutes, and an aluminum source temperature of 1450 degrees Celsius, forms a coating with a thickness of about 0.03 micrometers. This coating has uniform coverage and high light reflectivity.

[0039] Take 40 grams of gelatin, 6 grams of glycerin, and 90 ml of water, stir for 25 minutes, spread at a speed of 4 meters per minute, spread 4.5 grams per square meter, and dry at 40 degrees Celsius for 12 minutes to form a glue layer with a thickness of about 3.5 micrometers.

[0040] In hot stamping tests, the foil transferred well at 150 degrees Celsius and 2.5 MPa for 6 seconds, maintaining its gloss and exhibiting no edge blurring. After 90 days in a soil environment, approximately 25% of its quality was lost.

[0041] Flexibility tests showed no damage after 15 bends. This is because increasing the proportion of hydroxypropyl cellulose improves the flexibility of the base film, which helps with its adaptability during hot stamping.

[0042] In this embodiment, the release layer thickness was slightly increased, improving the smoothness of separation. The overall process showed good material compatibility and suitability for mass production. Degradation test data reflected that the higher cellulose content accelerated the microbial degradation process, making it suitable for cigarette brands with high environmental protection requirements.

[0043] Example 3 This embodiment provides a manufacturing process for biodegradable hot stamping foil for cigarette tipping paper.

[0044] Take 100g of polylactic acid, 40g of hydroxypropyl cellulose, and 300ml of ethyl acetate. Stir at 500 rpm for 50 minutes. Extrude at 200°C and 3m / min. The base film thickness is approximately 20 micrometers. This base film layer has enhanced strength and is suitable for high-temperature environments.

[0045] 50g beeswax, 12g vegetable oil, heat to 80 degrees Celsius, stir for 20 minutes, apply at a speed of 7 meters / minute, apply 3g per square meter, dry at 65 degrees Celsius for 30 minutes, the release layer thickness is about 2 micrometers, this release layer provides better wettability.

[0046] Mix 30g of water-soluble pigment, 25g of polyvinyl alcohol, and 140ml of water for 25 minutes. Apply at a rate of 6m / min, with a coating amount of 4g per square meter. Dry at 55°C for 20 minutes. The resulting color layer is approximately 3 micrometers thick and exhibits good abrasion resistance.

[0047] Vacuum evaporation, 7 minutes, aluminum source at 1500 degrees Celsius, coating thickness 0.04 micrometers, this coating has a long-lasting gloss.

[0048] Mix 40g gelatin, 8g glycerin, and 100ml water for 30 minutes. Apply at a rate of 5m / min, with a coating amount of 5g per square meter. Dry at 45°C for 15 minutes to achieve a glue layer thickness of 4 micrometers.

[0049] Hot stamping test: 155 degrees Celsius, 3 MPa, hot stamping for 7 seconds, complete transfer. Soil degradation: approximately 30% loss after 90 days.

[0050] The membrane showed no cracks after 20 bends in a flexibility test, and its high hydroxypropyl cellulose content enhanced the biocompatibility of the base membrane.

[0051] This embodiment optimizes drying time and reduces energy consumption. Increased coating thickness slightly improves gloss, but maintains a thin layer to ensure degradation. Tests show that adhesion reaches 2 N / cm at these parameters, suitable for cigarette tipping paper with high moisture content.

[0052] Example 4 Take 100g of polylactic acid, 50g of hydroxypropyl cellulose, and 350ml of ethyl acetate, and stir at 600 rpm for 60 minutes. Extrude at 210°C and a speed of 3.5m / min to produce a base film of 25 micrometers. This base film layer is relatively thick, providing better support.

[0053] 50g beeswax, 15g vegetable oil, heated to 85°C, stirred for 25 minutes, coated at 8m / min, coating amount 3.5g per square meter, dried at 70°C for 35 minutes, release layer 3 microns, this release layer thickness maximizes transfer efficiency.

[0054] Mix 30g of pigment, 30g of polyvinyl alcohol, and 160ml of water for 30 minutes. Apply at a rate of 7m / min, with a coating amount of 4.5g per square meter. Dry at 60°C for 25 minutes. The resulting color layer is 4 microns thick and has good color depth.

[0055] The coating is deposited for 8 minutes at an aluminum source of 1550 degrees Celsius, resulting in a coating thickness of 0.05 micrometers. This coating exhibits high reflectivity.

[0056] Mix 40g gelatin, 12g glycerin, and 120ml water for 35 minutes. Apply at a rate of 6m / min, with a coating amount of 5.5g per square meter. Dry at 50°C for 20 minutes, resulting in a 5-micron adhesive layer.

[0057] Hot stamping at 160 degrees Celsius and 3.5 MPa for 8 seconds yielded good results. Degradation occurred after 90 days with a 35% loss. Flexibility remained intact after 25 bends; at this ratio, a thicker base film provided better mechanical protection.

[0058] The process parameters offer flexibility for adjustment, making it easy to adapt to different equipment. Adhesion testing shows a result of 2.5 N / cm, balancing degradation rate with service life.

[0059] Comparative Example 1 Use 100 grams of conventional polyester film instead of the polylactic acid and hydroxypropyl cellulose mixture, with the other steps being the same, including the coating parameters for the release layer, color layer, plating layer, and adhesive layer.

[0060] The resulting hot stamping effect is similar, with complete transfer at 150 degrees Celsius and 2 MPa, and uniform gloss.

[0061] However, it showed no significant mass loss in soil environment after 90 days, and the flexibility test showed that it was comparable to the invention, but lacked degradation ability.

[0062] The comparative example shows that non-degradable substrates limit environmental performance, while the bio-based material combination in this process facilitates the decomposition process. Adhesion testing showed 1.8 N / cm, but the long-term environmental impact is significant and fails to meet sustainability requirements. In contrast, this invention introduces a degradation pathway through polylactic acid, improving overall applicability.

[0063] Comparative Example 2 Omit hydroxypropyl cellulose and use only 100g of polylactic acid to prepare the base film, with all other steps remaining the same. The base film exhibits reduced flexibility, leading to unevenness during extrusion and fine cracks on the surface after the release layer is applied. In the hot stamping test, uneven transfer occurred at 150°C and 2 MPa, with some edge peeling.

[0064] Soil degradation resulted in a 15% loss after 90 days. Flexibility testing showed it cracked after only 5 bends. This comparative example demonstrates that adding cellulose derivatives improved mechanical properties, supporting hot stamping applications, while pure polylactic acid was brittle and unable to meet the bending requirements of cigarette tipping paper. Adhesion was only 1.2 N / cm, impacting production efficiency. This invention avoids these problems through optimized mixing ratios.

[0065] Through the comparison of the above examples and comparative examples, it can be seen that the ratio of polylactic acid to hydroxypropyl cellulose in this process affects the strength and degradation rate of the base film. A lower ratio results in moderate strength and slower degradation, suitable for applications requiring high durability; a higher ratio enhances flexibility, accelerates degradation, and facilitates rapid decomposition. This allows for formulation adjustments based on the specific needs of cigarette tipping paper; for example, in high-humidity environments, a medium ratio can be chosen to balance durability and environmental friendliness. Variations in the thickness of each coating layer also affect overall performance: a thinner release layer facilitates transfer, while a thicker adhesive layer improves adhesion. The thin aluminum layer deposited by vacuum evaporation ensures gloss without hindering degradation.

[0066] Overall, the process is logically clear, uses conventional equipment, and utilizes readily available raw materials, contributing to the sustainable development of the cigarette industry. Test data shows that the adhesion of the hot stamping foil remains stable under pressures of 2-3.5 MPa, and the color maintains its luster without significant fading under standard light. Degradation testing, based on the soil burial method, reflects the material's decomposition potential under microbial action. These results support the process's potential for application in actual production and, by further drawing upon existing low-temperature hot stamping techniques, could be extended to other packaging fields.

[0067] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A manufacturing process for a special hot stamping foil for biodegradable cigarette tipping paper, characterized in that: Includes the following steps: (1) Preparation of base film: Polylactic acid and hydroxypropyl cellulose are mixed at a mass ratio of 1:0.2 to 1:0.5, solvent is added and stirred evenly, and the mixture is extruded to form a film with a thickness of 15-25 micrometers. (2) Release layer coating: Beeswax and vegetable oil are mixed at a mass ratio of 1:0.1 to 1:0.3, heated and melted, and then coated on the surface of the base film layer. After drying, a release layer with a thickness of 1-3 micrometers is formed. (3) Color coating: Water-soluble pigments and polyvinyl alcohol are mixed at a mass ratio of 1:0.5 to 1:1 and coated on the surface of the release layer. After drying, a color layer with a thickness of 2-4 micrometers is formed. (4) Coating formation: Aluminum is deposited on the surface of the color layer by vacuum evaporation to form a coating with a thickness of 0.02-0.05 micrometers; (5) Coating the adhesive layer: Mix gelatin and glycerin at a mass ratio of 1:0.1 to 1:0.3, coat the coating on the surface of the coating, and after drying, form an adhesive layer with a thickness of 3-5 micrometers to obtain hot stamping foil.

2. The manufacturing process of a biodegradable hot stamping foil for cigarette tipping paper as described in claim 1, characterized in that: In the preparation of the base film, the solvent is ethyl acetate, the stirring speed is 300-600 rpm, the stirring time is 30-60 minutes, and the extrusion temperature is 180-210 degrees Celsius.

3. The manufacturing process of a biodegradable hot stamping foil for cigarette tipping paper as described in claim 1, characterized in that: In the release layer coating process, the heating temperature is 70-85 degrees Celsius, the coating speed is 5-8 meters / minute, the drying temperature is 60-70 degrees Celsius, and the drying time is 20-35 minutes.

4. The manufacturing process of a biodegradable hot stamping foil for cigarette tipping paper as described in claim 1, characterized in that: In the color coating process, water is added to the pigment mixture as a solvent, the coating speed is 4-7 meters / minute, the drying temperature is 50-60 degrees Celsius, and the drying time is 15-25 minutes.

5. The manufacturing process of a biodegradable hot stamping foil for cigarette tipping paper as described in claim 1, characterized in that: During the formation of the coating, the vacuum degree is 10^-4 Pa and the evaporation time is 5-8 minutes.

6. The manufacturing process of a biodegradable hot stamping foil for cigarette tipping paper as described in claim 1, characterized in that: In the adhesive coating process, water is added to the gelatin mixture as a solvent, the coating speed is 3-6 meters / minute, the drying temperature is 40-50 degrees Celsius, and the drying time is 10-20 minutes.

7. The manufacturing process of a biodegradable hot stamping foil for cigarette tipping paper as described in claim 1, characterized in that: The mass ratio of polylactic acid to hydroxypropyl cellulose is 1:0.3 to 1:0.

4.

8. The manufacturing process of a biodegradable hot stamping foil for cigarette tipping paper as described in claim 1, characterized in that: The mass ratio of beeswax to vegetable oil is 1:0.

2.

9. The manufacturing process of a biodegradable hot stamping foil for cigarette tipping paper as described in claim 1, characterized in that: The mass ratio of the water-soluble pigment to polyvinyl alcohol is 1:0.7 to 1:0.

8.

10. The manufacturing process of a biodegradable hot stamping foil for cigarette tipping paper as described in claim 1, characterized in that: The mass ratio of gelatin to glycerin is 1:0.2.