A high temperature resistant frangible label and a method of making the same

Abstract

The application provides a preparation method of a high-temperature-resistant fragile label, and specifically comprises the following steps: S1, preparation of a fragile base material; S2, coating, compounding and curing of temperature-resistant pressure-sensitive adhesive; S3, post-processing: according to the required specifications and shapes, the compound product after being wound and cured is slitting and die cutting to obtain a high-temperature-resistant fragile label product; and the like. The high-temperature-resistant fragile label comprises, from top to bottom, a first release paper layer, a fragile surface material layer, a temperature-resistant pressure-sensitive adhesive layer and a second release paper layer. The fragile base material prepared under a specific formula and process is combined with the temperature-resistant pressure-sensitive adhesive, so that the high-temperature-resistant fragile label can still maintain structural stability and information readability under a high-temperature environment (such as 250 DEG C), has the characteristics of being broken at once and preventing transfer, and effectively solves the technical problems that the existing fragile label is not resistant to high temperature, and the high-temperature-resistant label is difficult to prevent from being counterfeited and removed.

Description

Technical Field

[0001] This invention relates to the field of label material technology, specifically to a label that combines high-temperature resistance and anti-counterfeiting / fragile properties, and its preparation method. Background Technology

[0002] Fragile paper labels have a wide range of applications, including but not limited to anti-counterfeiting verification of electronic products and high-end goods packaging, tamper-proofing and quality traceability of power equipment, auto parts, machinery, and document seals. Typical fragile and tamper-proof features can significantly reduce counterfeit and substandard products, maintain market economic order, and protect consumer rights.

[0003] However, the substrate and adhesive of conventional fragile paper labels have poor temperature resistance, causing them to lose their tamper-evident function at high temperatures. The main reasons for this are as follows: 1. Fragile substrate is not heat-resistant: In environments above 100℃, the resin emulsion in ordinary fragile paper substrates will oxidize more rapidly, causing the substrate to wrinkle, deform, and become more brittle at the edges. As a result, the substrate loses its original strength and cracks before use, rendering it unusable.

[0004] 2. The adhesive is not heat resistant: Ordinary acrylic pressure-sensitive adhesives are prone to softening, decomposition and breakage of their monomer molecular chains at high temperatures. As a result, the adhesive strength decreases, fragile paper labels may curl up at the edges, or even be completely peeled off.

[0005] When preparing coating slurries for such functional labels, acrylate copolymer emulsions are often chosen due to their excellent film-forming properties, adhesion, and stability. Existing technologies include various improved acrylate copolymer emulsions and their preparation methods for different applications. For example, patent CN114369399A discloses "a metakaolin-modified acrylate copolymer emulsion building waterproof coating and its preparation method," and patent CN119161540A discloses "a polyacrylate copolymer emulsion with a bimodal molecular weight distribution and its preparation method." These technologies primarily focus on improving the performance of the emulsion in building waterproofing or specific physical properties, but do not address how to use such emulsions to prepare label face materials that combine high-temperature resistance and brittleness.

[0006] High-temperature environments pose a significant challenge to the anti-lifting and tamper-evident properties of fragile paper labels. Existing technologies struggle to balance ensuring firm adhesion at high temperatures while maintaining fragility and tamper-evident properties upon peeling. Therefore, developing a fragile paper label that can withstand high temperatures (100°C to 250°C) and still possesses excellent tamper-evident properties upon peeling is a key technical challenge in this field. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a high-temperature resistant fragile label and its preparation method. This label, by combining a fragile substrate prepared under a specific formula and process with a high-temperature resistant pressure-sensitive adhesive, achieves structural stability and information readability even in high-temperature environments (such as 250°C), while also possessing anti-transfer properties that allow it to break upon removal. This effectively solves the technical problem that existing fragile labels are not heat-resistant, while high-temperature resistant labels are difficult to remove for anti-counterfeiting purposes.

[0008] To achieve the above technical solution, the present invention provides a method for preparing a high-temperature resistant and fragile label, which specifically includes the following steps: S1. Preparation of fragile substrate: S11. Slurry preparation: According to the weight parts, mix 10-12 parts of kaolin, 4-8 parts of titanium dioxide, 0.5-2 parts of matting agent and 10-15 parts of purified water in a disperser and stir beforehand. Then, add 1-3 parts of dispersing resin, 0.1-0.8 parts of aluminum hydroxide, 0.05-0.2 parts of organosilicon defoamer and 0.2-1 parts of dispersant in the slurry mixing tank and mix thoroughly. S12. Ingredients: Add 8-10 parts of acrylate copolymer emulsion, 0.01-0.1 parts of silicone defoamer, 0.1-0.3 parts of wetting agent, 0.1-0.3 parts of dimethyl ether, and 0.1-0.3 parts of thickener to the slurry prepared in step S11 in sequence, and stir thoroughly to form a uniform coating slurry; S13. Coating the substrate and drying: Use a comma doctor blade coater to coat the first release paper substrate on the release surface. The coating amount is 50-60g / m². Use a gradient heating method to dry. The final drying temperature is 120℃. After winding, a high-temperature resistant and fragile substrate is obtained. S2. Coating, lamination, and curing of temperature-resistant pressure-sensitive adhesive: S21. Adhesive preparation: Dilute 100 parts of 250°C heat-resistant acrylic pressure-sensitive adhesive with solvent and mix thoroughly with 0.3-1 parts of crosslinking agent, then let stand to defoam; S22. Coating: Using a comma-shaped doctor blade coater, the prepared adhesive is evenly coated onto the release layer of the second release paper substrate. The coating amount is 40-50 g / m². The second release paper is then moistened, dried, and wound up to obtain the adhesive substrate. S23. Composite: The fragile side of the high-temperature resistant and fragile substrate obtained in step S13 is bonded to the adhesive side of the adhesive substrate obtained in step S22 and then rolled up to obtain the composite product. S23. Curing: Place the wound composite product at room temperature for 48 hours to allow the adhesive layer to fully cross-link and cure. S3, Post-processing: The rolled-up and cured composite product is slit and die-cut according to the required specifications and shapes to obtain high-temperature resistant and fragile label products.

[0009] Preferably, in step S11, 11.26 parts by weight of kaolin, 6.25 parts by weight of titanium dioxide, 1 part by weight of matting agent and 13 parts by weight of purified water are mixed in a disperser and stirred beforehand. Then, 2.25 parts by weight of dispersion resin, 0.6 parts by weight of aluminum hydroxide, 0.1 parts by weight of silicone defoamer and 0.5 parts by weight of dispersant are added in sequence and mixed thoroughly in a mixing tank.

[0010] Preferably, the dispersing resin is one of stearamide, vinyl bis-stearamide, glyceryl monostearate, glyceryl tristearate, and oleyl acyl; and the dispersant is one of polyoxyethylene, polyoxypropylene ether, and high molecular weight polyurethane.

[0011] Preferably, in step S12, 9.6 parts of acrylate copolymer emulsion, 0.07 parts of silicone defoamer, 0.17 parts of wetting agent, 0.17 parts of dimethyl ether, and 0.22 parts of thickener are filtered sequentially and added to the slurry obtained in step S11, and then stirred thoroughly to form a uniform coating slurry.

[0012] Preferably, the wetting agent is one of sodium dodecylbenzene sulfonate, sodium secondary alkyl sulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether; the thickener is one of hydroxyethyl cellulose and hydroxypropyl methylcellulose.

[0013] Preferably, in step S13, the first release paper substrate is white glassine paper.

[0014] Preferably, the drying process in step S13 employs the following gradient heating method: S131. The release paper substrate after coating is conveyed to a low-temperature preheating box at 30-60°C for low-temperature preheating. The release paper substrate is heated to 60°C in the low-temperature preheating box at a rate of 5°C / minute to gently evaporate the moisture and solvent in the coating. S132. The release paper substrate, which has been preheated to 60°C, is sent into the main drying oven at 60-120°C for drying. The release paper substrate is heated to 120°C at a rate of 10°C / minute to allow the coating to form a basic skeleton structure. S133. Maintain high-temperature curing in a 120°C high-temperature drying oven for 10-15 minutes; S134. The high-temperature cured release paper is transported to a cold box for gradual cooling, and the release paper is controlled to cool down to room temperature at a rate not exceeding 5°C / minute.

[0015] Preferably, in step S21, 100 parts of a heat-resistant acrylic pressure-sensitive adhesive capable of withstanding 250°C are diluted with ethyl acetate solvent and then thoroughly mixed with 0.6 parts of an isocyanate crosslinking agent, and allowed to stand to defoam.

[0016] The present invention also provides a high-temperature resistant fragile label, which is prepared by the above-described method and comprises, from top to bottom: a first release paper layer, a fragile face material layer, a temperature-resistant pressure-sensitive adhesive layer, and a second release paper layer.

[0017] The beneficial effects of the method for preparing a high-temperature resistant and fragile label provided by this invention are as follows: (1) The preparation method of this high-temperature resistant fragile label involves forming a film on release paper using a coating slurry with a specific formula (containing kaolin, titanium dioxide, acrylic copolymer emulsion, etc.), creating a loosely structured and controllably brittle "fragile face material layer". This face material layer is combined with the subsequently coated high-temperature pressure-sensitive adhesive layer, resulting in a label that possesses both excellent heat resistance and the characteristic of a fragile face material layer when removed. The entire process is clear, controllable, and suitable for large-scale production.

[0018] (2) This invention, through a unique slurry formulation design and a rigorous gradient drying process, successfully prepared a label material that remains stable at high temperatures (e.g., 250°C) while also possessing "fragile" anti-counterfeiting properties. When combined with a specially formulated high-temperature pressure-sensitive adhesive, the resulting label product perfectly unifies the two originally contradictory functional characteristics of "high-temperature resistance" and "fragile anti-counterfeiting." This label can be widely used in fields requiring high-temperature processing and sterilization, and with strict anti-counterfeiting requirements, such as SMT electronic component traceability, high-temperature sterilized medical device labeling, and high-temperature component management in automotive engines, demonstrating significant practical value and market potential. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the layered structure of the high-temperature resistant and fragile label in this invention.

[0020] Figure 2 This is a flowchart of the preparation method in this invention.

[0021] In the diagram: 1. First release paper layer; 2. Fragile face material layer; 3. Temperature-resistant pressure-sensitive adhesive layer; 4. Second release paper layer. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0023] Example 1: A method for preparing a high-temperature resistant and fragile label.

[0024] Reference Figures 1 to 2 As shown, this invention provides a method for preparing a high-temperature resistant and fragile label, specifically including the following steps: S1. Preparation of fragile substrate: S11. Slurry Preparation: In a high-speed disperser, add 13 parts (by weight, the same below) of purified water and start stirring. While stirring, add 11.26 parts of kaolin, 6.25 parts of titanium dioxide, and 1 part of matting agent in sequence, and disperse for 5 minutes to form a premixed slurry. Transfer the premixed slurry to a mixing tank, and add 2.25 parts of stearamide (dispersing resin), 0.6 parts of aluminum hydroxide, 0.1 parts of silicone defoamer, and 0.5 parts of high molecular weight polyurethane dispersant in sequence. Stir at 800 rpm for 30 minutes until the mixture is uniform and there are no visible particles.

[0025] S12. Ingredients: Slowly add 9.6 parts of commercially available acrylate copolymer emulsion (solid content approximately 50%), 0.07 parts of silicone defoamer, 0.17 parts of alkylphenol polyoxyethylene ether (wetting agent), 0.17 parts of dimethyl ether, and 0.22 parts of hydroxyethyl cellulose (thickener) sequentially to the above-mentioned slurry mixing tank. Maintain a slow stirring speed of 300 rpm during the addition process. After all the ingredients are added, increase the stirring speed to 500 rpm and continue stirring for 40 minutes to form a uniform, fine coating slurry with suitable viscosity.

[0026] S13. Coating and Drying: White glassine release paper is selected as the first substrate. A comma-shaped doctor blade coater is used to coat the release surface, controlling the wet coating amount to 55 g / m². The coated substrate is immediately sent into the drying tunnel.

[0027] The drying process employs a gradient heating method: first, it enters a low-temperature preheating zone at 50°C, where the temperature is increased to 60°C at a rate of approximately 5°C / min to gently evaporate moisture; then, it enters the main drying zone, where the temperature starts at 60°C and is programmed to increase to 120°C at a rate of approximately 10°C / min, and is held at this temperature for 12 minutes to allow the coating to fully cure and form a skeleton; finally, it enters the cooling zone, where it is slowly cooled to room temperature (approximately 25°C) at a rate not exceeding 5°C / min. After drying, it is rolled up to obtain a high-temperature resistant and brittle substrate.

[0028] S2. Coating, lamination, and curing of temperature-resistant pressure-sensitive adhesive: S21. Adhesive preparation: Take 100 parts of heat-resistant acrylic pressure-sensitive adhesive (solid content about 60%) that can withstand 250℃, add an appropriate amount of ethyl acetate solvent to dilute to a viscosity suitable for coating, then add 0.6 parts of isocyanate crosslinking agent (such as brand L-75), stir thoroughly to mix evenly, and let stand for 30 minutes to remove air bubbles.

[0029] S22. Coating: Select another roll of glassine release paper as the second substrate. Use a comma-shaped doctor blade coater to evenly coat the prepared adhesive on its release surface, controlling the dry adhesive coating amount to 45 g / m². After coating, dry the solvent in an 85°C oven to form a heat-resistant pressure-sensitive adhesive layer on the second release paper. Then, rewind to obtain the adhesive substrate.

[0030] S23. Lamination: Unwind the high-temperature resistant and fragile substrate obtained in step S13, aligning its fragile side (i.e., the coating side) with the adhesive side of the adhesive substrate obtained in step S22, and laminate it using a lamination roller under pressure. The lamination pressure is controlled at 0.3-0.5 MPa, and the lamination speed is matched with the coating line speed. After lamination, rewind to obtain a preliminarily laminated roll.

[0031] S24. Curing: After winding, the composite roll material is left to stand and mature for 48 hours at room temperature (23±2℃) and relative humidity (50±5%) to allow the crosslinking agent in the pressure-sensitive adhesive layer to fully react and complete the curing process.

[0032] S3, Post-processing: After the composite roll material has been cured and matured, it is slit into rolls of a specific width on a slitting machine according to customer requirements. Then, it is die-cut into the required label shape (such as rectangle, circle, etc.) by a die-cutting machine. Finally, it is inspected and packaged to obtain the final high-temperature resistant fragile label product.

[0033] The label's structure, from top to bottom, consists of: a first release paper (white glassine), a fragile faceplate layer, a temperature-resistant pressure-sensitive adhesive layer, and a second release paper (glassine). In actual use, first peel off the second release paper, then use the adhesive of the temperature-resistant pressure-sensitive adhesive layer to attach the label to the component's surface, and finally peel off the first release paper. Users can write or mark on the fragile faceplate layer; if they want to remove the label, the fragile faceplate layer has a "breaks upon removal" anti-counterfeiting feature.

[0034] Comparative Example 1 Ordinary commercial fragile paper (commercially available, mainly composed of short-fiber wood pulp paper) is used as the face material, and a general-purpose acrylic pressure-sensitive adhesive (temperature resistant to about 80°C) is coated on the back. The rest of the preparation process is similar to that in Example 1 to produce a conventional fragile label.

[0035] Performance testing The label samples prepared in Example 1 and Comparative Example 1 were subjected to the following tests: 1. High temperature resistance test: Affix the label sample to a clean aluminum plate, place it in a 250℃ constant temperature oven, keep it for 30 minutes, then remove it and cool it to room temperature.

[0036] Example 1 Label: The surface material has no bubbling, cracking, discoloration or curling, the printed information is clear, the adhesive layer is not ineffective, and the label can be firmly pasted on the aluminum plate.

[0037] Comparative Example 1 Label: The surface material is severely charred, brittle, curled and peeled up, completely carbonized and turned black, the information is unreadable, the adhesive layer loses its stickiness, and the label falls off automatically.

[0038] 2. Fragility test (room temperature): Place the label sample that has not been treated with high temperature on a glass plate, let it stand for 24 hours, and then try to peel off the label at a uniform speed and in a 180-degree direction.

[0039] Example 1 Label: When peeled off, the surface layer breaks irregularly and cannot be completely peeled off. The fragments are basically adhered to the adhesive layer, which meets the requirements of fragile anti-counterfeiting.

[0040] Comparative Example 1 Label: When peeled off, the surface layer also cracked and could not be completely removed, meeting the requirement of being fragile.

[0041] 3. Fragility test (after high temperature): The label of Example 1, after being treated at 250℃ for 30 minutes, was cooled to room temperature and then a peel-off test was performed.

[0042] Example 1 label: When peeled off, the surface layer still fractured brittlely and could not be transferred completely, proving that it still retains its anti-counterfeiting function after high-temperature treatment. In contrast, the label in Comparative Example 1 was completely destroyed in the high-temperature test, making this test unnecessary.

[0043] Test results show that the high-temperature resistant fragile label prepared by this invention successfully maintains its appearance, adhesiveness, and key "break-on-tear" anti-counterfeiting function after withstanding a high temperature of 250℃. Its overall performance is significantly better than that of traditional fragile labels.

[0044] The above description is only a preferred embodiment of the present invention, but the present invention should not be limited to the content disclosed in the embodiments and drawings. Therefore, any equivalent or modified embodiments made without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-temperature resistant and fragile label, characterized in that... Specifically, the steps include the following: S1. Preparation of fragile substrate: S11. Slurry preparation: According to the weight parts, mix 10-12 parts of kaolin, 4-8 parts of titanium dioxide, 0.5-2 parts of matting agent and 10-15 parts of purified water in a disperser and stir beforehand. Then, add 1-3 parts of dispersing resin, 0.1-0.8 parts of aluminum hydroxide, 0.05-0.2 parts of organosilicon defoamer and 0.2-1 parts of dispersant in the slurry mixing tank and mix thoroughly. S12. Ingredients: Add 8-10 parts of acrylate copolymer emulsion, 0.01-0.1 parts of silicone defoamer, 0.1-0.3 parts of wetting agent, 0.1-0.3 parts of dimethyl ether, and 0.1-0.3 parts of thickener to the slurry prepared in step S11 in sequence, and stir thoroughly to form a uniform coating slurry; S13. Coating the substrate and drying: Use a comma doctor blade coater to coat the first release paper substrate on the release surface. The coating amount is 50-60g / m². Use a gradient heating method to dry. The final drying temperature is 120℃. After winding, a high-temperature resistant and fragile substrate is obtained. S2. Coating, lamination, and curing of temperature-resistant pressure-sensitive adhesive: S21. Adhesive preparation: Dilute 100 parts of 250°C heat-resistant acrylic pressure-sensitive adhesive with solvent and mix thoroughly with 0.3-1 parts of crosslinking agent, then let stand to defoam; S22. Coating: Using a comma-shaped doctor blade coater, the prepared adhesive is evenly coated onto the release layer of the second release paper substrate. The coating amount is 40-50 g / m². The second release paper is then moistened, dried, and wound up to obtain the adhesive substrate. S23. Composite: The fragile side of the high-temperature resistant and fragile substrate obtained in step S13 is bonded to the adhesive side of the adhesive substrate obtained in step S22 and then rolled up to obtain the composite product. S23. Curing: Place the finished composite product at room temperature for 48 hours after winding to allow the adhesive layer to fully cross-link and cure. S3, Post-processing: The rolled-up and cured composite product is slit and die-cut according to the required specifications and shapes to obtain high-temperature resistant and fragile label products.

2. The method for preparing the high-temperature resistant fragile label as described in claim 1, characterized in that, In step S11, 11.26 parts by weight of kaolin, 6.25 parts by weight of titanium dioxide, 1 part by weight of matting agent and 13 parts by weight of purified water are mixed in a disperser and stirred beforehand. Then, 2.25 parts by weight of dispersion resin, 0.6 parts by weight of aluminum hydroxide, 0.1 parts by weight of silicone defoamer and 0.5 parts by weight of dispersant are added in sequence and mixed thoroughly in a mixing tank.

3. The method for preparing the high-temperature resistant fragile label as described in claim 2, characterized in that, The dispersing resin is one of stearamide, vinyl bis-stearamide, glyceryl monostearate, glyceryl tristearate, or oleyl acyl; the dispersant is one of polyoxyethylene, polyoxypropylene ether, or high-molecular-weight polyurethane.

4. The method for preparing the high-temperature resistant fragile label as described in claim 1, characterized in that, In step S12, 9.6 parts of acrylate copolymer emulsion, 0.07 parts of silicone defoamer, 0.17 parts of wetting agent, 0.17 parts of dimethyl ether, and 0.22 parts of thickener are filtered sequentially and then added to the slurry prepared in step S11, and stirred thoroughly to form a uniform coating slurry.

5. The method for preparing a high-temperature resistant fragile label as described in claim 4, characterized in that, The wetting agent is one of sodium dodecylbenzene sulfonate, sodium secondary alkyl sulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether; the thickener is one of hydroxyethyl cellulose and hydroxypropyl methylcellulose.

6. The method for preparing a high-temperature resistant fragile label as described in claim 1, characterized in that, In step S13, the first release paper substrate is white glassine paper.

7. The method for preparing a high-temperature resistant fragile label as described in claim 1, characterized in that, In step S13, the drying process employs the following gradient heating method: S131. The release paper substrate after coating is conveyed to a low-temperature preheating box at 30-60°C for low-temperature preheating. The release paper substrate is heated to 60°C in the low-temperature preheating box at a rate of 5°C / minute to gently evaporate the moisture and solvent in the coating. S132. The release paper substrate, which has been preheated to 60°C, is sent into the main drying oven at 60-120°C for drying. The release paper substrate is heated to 120°C at a rate of 10°C / minute to allow the coating to form a basic skeleton structure. S133. Maintain high-temperature curing in a 120°C high-temperature drying oven for 10-15 minutes; S134. The high-temperature cured release paper is transported to a cold box for gradual cooling, and the release paper is controlled to cool down to room temperature at a rate not exceeding 5°C / minute.

8. The method for preparing a high-temperature resistant fragile label as described in claim 1, characterized in that, In step S21, 100 parts of heat-resistant acrylic pressure-sensitive adhesive that can withstand 250°C are diluted with ethyl acetate solvent and then thoroughly mixed with 0.6 parts of isocyanate crosslinking agent, and allowed to stand to defoam.

9. A high-temperature resistant and fragile label, characterized in that: Prepared using any one of the preparation methods described in claims 1-8, the product comprises, from top to bottom: a first release paper layer, a fragile face material layer, a temperature-resistant pressure-sensitive adhesive layer, and a second release paper layer.

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