A label adhesive for a refrigerated environment and a method of making the same

Abstract

This invention relates to the field of adhesive technology, specifically to a label adhesive for use in freezing environments and its preparation method. It aims to solve the problems of difficulty in achieving cohesion and balancing initial tack in existing technologies, and susceptibility to moisture erosion leading to delamination. The label adhesive of this invention is mainly composed of an epoxidized styrene-isoprene-styrene copolymer, a star-shaped SIS, a plasticizer, an anti-aging agent, a dynamic crosslinking agent, and a grafted modified C5 petroleum resin tackifying resin. In this invention, the epoxidized styrene-isoprene-styrene copolymer and the star-shaped SIS are vacuum-dried and then mixed; then, a premixed system with a plasticizer and an anti-aging agent is heated and melted to form a basic colloid; subsequently, a dynamic crosslinking agent and a core-shell tackifying resin are added and reacted at a certain temperature to induce partial crosslinking; then, the mixture is cooled; finally, the label adhesive is obtained by vacuum degassing, cooling, and roll forming.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, and more specifically to a label adhesive for use in freezing environments and its preparation method. Background Technology

[0002] In existing technologies, pressure-sensitive label adhesives for low-temperature environments are typically formulated using styrene-isoprene-styrene block copolymer (SIS) elastomers, tackifying resins, and plasticizers. These pressure-sensitive adhesives provide good initial tack and holding power at room temperature, adhering firmly to the substrate. However, their performance deteriorates significantly at low temperatures, especially under ultra-low temperature conditions, where they are prone to loss of tack and cracking.

[0003] Some existing low-temperature pressure-sensitive adhesives retain a certain degree of softness and tackiness at around -10°C, allowing coated labels to adhere to frozen surfaces without detaching. However, when the temperature drops to -15°C or even lower, the adhesive begins to harden, and the adhesion weakens rapidly, resulting in labels not sticking properly. Especially when the temperature drops further below -20°C, traditionally formulated pressure-sensitive adhesives become extremely hard and brittle due to vitrification, almost completely losing their tackiness and becoming unusable in ultra-low temperature environments. For example, existing patent CN102604570A discloses a hot-melt pressure-sensitive adhesive for HDPE self-adhesive rolls and its preparation method. While this improves some low-temperature performance, it lacks an active mechanism to cope with condensation, and the purely physical blend system exhibits poor phase stability under extreme temperature changes.

[0004] Furthermore, the presence of humidity or moisture further deteriorates the performance of adhesives in low-temperature environments. In cold storage or refrigerated transport environments, the low-temperature air often contains moisture. The condensation of moisture on the adhesive surface or interface can cause localized loss of adhesion or separation of the adhesive from the surface of the adhered object. Existing low-temperature pressure-sensitive adhesives may achieve a certain bonding effect in dry, low-temperature environments, but once moisture is present in the environment, the labels quickly become detached or fall off. For example, under conditions below -10°C and accompanied by high humidity, traditional label adhesives often fail to adhere firmly. Moisture seeps into the adhesive layer, causing a decrease in adhesion between the adhesive and the adhered surface, resulting in label displacement, lifting, or even complete detachment.

[0005] The reasons for the above problems are as follows: First, conventional SIS-based adhesives lack sufficient toughness and initial tack at ultra-low temperatures. Although SIS elastomers still retain some initial tack at slightly lower temperatures, as the temperature drops to extremely low levels, the SIS-based colloid itself becomes brittle, and its surface wetting ability and adhesion to the substrate decrease significantly. At the same time, tackifying resins such as petroleum resins and rosin resins change from their original viscoelastic state to a glassy state at low temperatures, resulting in a sharp decrease in peel force and overall degradation of adhesive performance. Second, the contradiction between cohesive strength (holding power) and initial tack performance in adhesive formulations is prominent. To ensure flexibility at low temperatures, the proportion of plasticizers needs to be increased or the molecular weight reduced, which weakens the cohesive force of the adhesive layer, leading to a decrease in durable adhesion performance at room temperature; conversely, adding high molecular weight elastomers or crosslinking agents to improve cohesive force easily makes the colloid hard, resulting in insufficient initial tack at low temperatures. Existing technologies struggle to find a balance point that is both flexible and has sufficient cohesive force over a wide temperature range. Third, moisture in the environment can penetrate the adhesive layer and accumulate at the interface, triggering a moisture erosion effect. Water vapor condensation can form a water film or ice crystals at the interface between the adhesive layer and the substrate, damaging the adhesion; moisture may also cause the performance degradation of some hydrophilic components, reducing the strength of the adhesive.

[0006] Tire labeling is a typical application scenario, requiring labels to adhere firmly to the tire rubber surface in low-temperature or even extremely cold environments. The tire rubber surface often has release agent residue and an irregular texture, increasing the difficulty of adhesion. In cold northern regions during winter or under refrigerated transport conditions, the label adhesive on the tire surface must maintain sufficient adhesion strength and toughness in a low-temperature environment of around -38°C, and resist the attack of moisture from the cold, humid outdoor air. However, existing commercially available tire label adhesives fail to meet these requirements under such harsh conditions, necessitating an improved label adhesive solution that can reliably adhere in ultra-low temperature (-38°C) and high-humidity environments. Summary of the Invention

[0007] The main objective of this invention is to overcome the technical defects of existing low-temperature label adhesives, such as insufficient ultra-low temperature toughness, difficulty in achieving both cohesive strength and balanced initial tack, and susceptibility to moisture erosion. This invention provides a label adhesive for use in frozen environments and its preparation method. The label adhesive obtained by this invention can be used in extreme low-temperature environments (-38℃) and in environments containing moisture. Labels coated with this adhesive can adhere firmly to the surface of substrates such as frozen product packaging bags or tires for a long period without falling off.

[0008] A label adhesive for use in freezing environments and its preparation method are disclosed below:

[0009] S1: The epoxidized styrene-isoprene-styrene copolymer and the star-shaped SIS raw material are dried to fully remove the adsorbed moisture, and then mixed to obtain a SIS elastomer mixture. S2: Add cycloalkyl rubber oil plasticizer and 1010 antioxidant to a stainless steel reactor, start stirring and heat up, add the SIS elastomer mixture prepared in step S1, continue heating and stirring to obtain the basic colloid; S31: Add 30 parts of C5 petroleum resin, 20 parts of butyl acrylate monomer, and 0.5 parts of dicumyl peroxide initiator to a reaction vessel, heat and react to obtain grafted modified C5 petroleum resin tackifying resin. S32: Adjust the temperature of the base colloid, add γ-aminopropyltriethoxysilane dynamic crosslinking agent, stir for 5 minutes, then add grafted modified C5 petroleum resin thickening resin, stir, then vacuum dry, and finally add dibutyltin dilaurate catalyst to obtain crosslinked colloid. S4: Cool the cross-linked colloid to 80°C, stop heating, seal the feeding port, start the vacuum pump to degas the colloid in the reactor for 10 minutes, pour out the degassed colloid while it is still hot, calender it through a cooling metal roller press, adjust the roller gap to press the colloid into a film, cool and cure it to obtain the label adhesive of the present invention.

[0010] Further, the amount of each component in the label adhesive is as follows: 10-20 parts of epoxidized styrene-isoprene-styrene copolymer, 10-20 parts of star-shaped SIS, 20-30 parts of naphthenic rubber oil plasticizer, 1-2 parts of 1010 antioxidant, 1-3 parts of γ-aminopropyltriethoxysilane dynamic crosslinking agent, and then 40-50 parts of grafted modified C5 petroleum resin tackifying resin and 0.4-0.6 parts of dibutyltin dilaurate catalyst additive.

[0011] Furthermore, the drying described in step S1 specifically involves vacuum drying at 60°C for 2 hours.

[0012] Furthermore, the heating mentioned in step S2 specifically refers to the temperature rising to 120°C to 130°C.

[0013] Furthermore, the heating and stirring described in step S2 specifically involves heating to 140°C to 150°C and maintaining stirring for 30 to 60 minutes.

[0014] Furthermore, the heating reaction described in step S31 specifically involves heating to 130°C and stirring the reaction for 2 hours under nitrogen protection.

[0015] Furthermore, the adjustment of the base colloid temperature in step S32 specifically refers to adjusting the base colloid temperature to 130℃~140℃.

[0016] Furthermore, the stirring described in step S32 specifically involves stirring at a speed of 60-100 rpm for 10-20 minutes.

[0017] Furthermore, the vacuum drying described in step S32 specifically involves drying under vacuum at 135°C for 30 minutes.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention uses a combination of epoxidized styrene-isoprene-styrene copolymer and star-shaped SIS and a reasonable amount of plasticizer. The adhesive of the present invention still maintains good flexibility and adhesion at an ultra-low temperature of -38℃.

[0019] (2) Through the micro-crosslinking network formed by dynamic crosslinking and the high molecular weight contribution of star-shaped SIS, the adhesive of the present invention can significantly improve the cohesive strength and holding power at room temperature while ensuring the initial tack at low temperature. Attached Figure Description

[0020] Figure 1 This is a process flow for preparing a label adhesive for use in freezing environments.

[0021] Figure 2 The spectrum is from the test in Experiment Example 1. Detailed Implementation

[0022] The following embodiments further explain and illustrate the technical solutions of the present invention. It is particularly noted that each specific embodiment is a specific interpretation of the technical solution and should not be considered as a limitation on the scope of protection of the present invention. Those skilled in the art still have the right to modify the technical solutions of these embodiments and make equivalent substitutions for some or all of the technical features, and these modifications or substitutions do not change the essence of the corresponding technical solutions, nor do they cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention. Figure 1 The diagram shows a manufacturing process for label adhesive used in freezing environments. The detailed manufacturing steps are as follows: 1. SIS elastomer blend The epoxidized styrene-isoprene-styrene copolymer and the star-shaped SIS raw material were placed in a vacuum drying oven and dried under vacuum to fully remove the adsorbed moisture. The mixture was then mixed to obtain a SIS elastomer mixture. Introducing polar epoxy groups can improve the flexibility of SIS segments at the glass transition temperature and their compatibility with polar tackifying resins, thereby enhancing low-temperature toughness and adhesion. Simultaneously, epoxy groups provide active sites for subsequent crosslinking reactions. Star-shaped SIS is a multi-branched SIS elastomer with a star-shaped molecular structure. Compared to linear SIS, star-shaped SIS has a higher molecular weight and more functional sites, thus imparting higher cohesive strength and sag resistance to the colloid. This invention uses a compound of E-SIS and star-shaped SIS in a certain proportion, utilizing the modified polarity and reactivity of E-SIS to improve adhesion performance under low-temperature and humid conditions, while leveraging star-shaped SIS to enhance the cohesive force and mechanical strength of the colloid. The two complement each other, fundamentally alleviating the contradiction between achieving both initial tack and holding power at low temperatures.

[0023] 2. Preparation of basic colloids Add cycloalkyl rubber oil plasticizer and 1010 antioxidant to a stainless steel reactor, start stirring and heat up, add the prepared SIS elastomer mixture, continue heating and stirring until the system becomes a uniform, transparent, viscous colloid without unmelted particles, and obtain the basic colloid. Plasticizers are used to lower the hardening point and glass transition temperature of adhesive systems, giving the adhesive layer the necessary softness and surface wettability at low temperatures. They maintain low viscosity even at low temperatures, helping the adhesive to wet the substrate surface at -38°C and enhancing initial tack. Anti-aging agents are used to improve the weather resistance of adhesives, preventing aging and deterioration of the material during high-temperature melting preparation and subsequent use.

[0024] 3. Dynamic crosslinking and thickening resin addition C5 petroleum resin, butyl acrylate monomer, and dicumyl peroxide initiator were added to a reactor and heated under nitrogen protection to carry out a graft copolymerization reaction, thereby obtaining graft-modified C5 petroleum resin tackifying resin. γ-aminopropyltriethoxysilane dynamic crosslinking agent and graft-modified C5 petroleum resin tackifying resin were added to the base colloid, and then dried under vacuum at 135°C for 30 minutes. Finally, dibutyltin dilaurate catalyst was added to promote the reaction, resulting in a crosslinked colloid. The role of dynamic crosslinking agents is to perform in-situ crosslinking modification of the elastomer matrix during the preparation process, forming a certain degree of three-dimensional network structure, thereby improving the cohesive strength and heat and moisture resistance of the adhesive. The dynamic crosslinking agent possesses hydrolyzable functional groups and active groups that undergo condensation or addition reactions with the elastomer / resin. Under high-temperature conditions, its thiol groups can chemically bond with the unsaturated bonds of the SIS molecular chain. Simultaneously, the alkoxy groups of silanes hydrolyze to silanols in the presence of trace amounts of moisture and condense with each other, or undergo condensation reactions with epoxy groups, hydroxyl groups, etc., thus building "bridges" between elastomer chains and between the elastomer and the resin. Through the introduction of dynamic crosslinking agents, the adhesive system achieves dynamic vulcanization crosslinking during processing: that is, forming a microscale crosslinked network during vigorous mixing, while maintaining the overall thermoplastic elastomer properties. This semi-crosslinked structure effectively improves the cohesive force and structural stability of the adhesive layer, making the adhesive less prone to flow and more durable at room temperature, while maintaining a certain degree of flexibility at low temperatures due to the moderate crosslinking density, preventing excessive hardening. More importantly, the silane coupling network improves the water resistance of the colloid: the siloxane bonds and cross-linking structure reduce the exposure and movement of hydrophilic groups, making it difficult for water vapor to penetrate and accumulate inside the colloid, thereby improving its resistance to damp cold.

[0025] The grafted and modified C5 petroleum resin tackifying resin ensures that the tackifying resin is uniformly dispersed in the matrix without precipitation, and can still deform in synergy with the elastomer at low temperatures without becoming a brittle defect point. It has both good low-temperature tackifying effect and humidity stability, which significantly improves the initial tack and peel strength of the label adhesive of this invention at -38°C, while avoiding the problem of the sharp decline in low-temperature performance caused by the poor compatibility of conventional tackifying resins.

[0026] 4. Degassing and molding Cool the cross-linked colloid, stop heating, seal the feeding port, start the vacuum pump to degas the colloid in the reactor, pour out the degassed colloid while it is still hot, calender it through a cooled metal roller press, adjust the roller gap to press the colloid into a film, cool and cure it to obtain the label adhesive of the present invention.

[0027] Example 1 Table 1 Raw Material Information Table

[0028] A label adhesive for use in freezing environments and its preparation method, the preparation steps of which are as follows: S1: Place 15 parts by weight of epoxidized styrene-isoprene-styrene copolymer and 15 parts by weight of star-shaped SIS raw material in a vacuum drying oven and dry under vacuum at 60°C for 2 hours to fully remove adsorbed moisture. After drying, mix to obtain SIS elastomer mixture. S2: Add 25 parts of naphthenic rubber oil plasticizer and 1.5 parts of 1010 antioxidant to a stainless steel reactor, start stirring and heat up. When the temperature reaches 125°C, add the SIS elastomer mixture prepared in step S1, continue heating to 145°C and maintain stirring for 45 minutes until the system becomes a uniform, transparent, viscous colloid without unmelted particles, and obtain the basic colloid. S31: Add 30 parts of C5 petroleum resin, 20 parts of butyl acrylate monomer, and 0.5 parts of dicumyl peroxide initiator to a reaction vessel, heat to 130°C, stir and react for 2 hours under nitrogen protection to carry out graft copolymerization reaction and obtain graft-modified C5 petroleum resin thickening resin. S32: Adjust the temperature of the base colloid to 135℃, add 2 parts of γ-aminopropyltriethoxysilane dynamic crosslinking agent, stir for 5 minutes, then add 45 parts of grafted modified C5 petroleum resin thickening resin, stir at 80 rpm for 15 minutes, then dry under vacuum at 135℃ for 30 minutes, and finally add 0.5 parts of dibutyltin dilaurate catalyst to promote the reaction and obtain the crosslinked colloid; S4: Cool the cross-linked colloid to 80°C, stop heating, seal the feeding port, start the vacuum pump to degas the colloid in the reactor for 10 minutes, pour out the degassed colloid while it is still hot, calender it through a cooling metal roller press, adjust the roller gap to press the colloid into a film, cool and cure it to obtain the label adhesive of the present invention.

[0029] Example 2 The preparation method is the same as in Example 1, but with the following differences: In step S1: 10 parts of epoxidized styrene-isoprene-styrene copolymer and 10 parts of star-shaped SIS raw material are placed in a vacuum drying oven; In step S2: Add 20 parts of naphthenic rubber oil plasticizer and 1 part of 1010 antioxidant, start stirring and heat up. When the temperature reaches 120°C, add the SIS elastomer mixture prepared in step S1, continue heating to 140°C, and maintain stirring for 60 minutes. In step S32: the temperature of the base colloid is adjusted to 130℃, 1 part of γ-aminopropyltriethoxysilane dynamic crosslinking agent is added; then 40 parts of grafted modified C5 petroleum resin thickening resin is added, the mixture is stirred at 60 rpm for 120 minutes, and 0.4 parts of dibutyltin dilaurate catalyst is added. In step S42: Use a low speed of 40 rpm to stir and mix for 10 minutes.

[0030] Example 3 The preparation method is the same as in Example 1, but with the following differences: In step S1: 20 parts of epoxidized styrene-isoprene-styrene copolymer and 20 parts of star-shaped SIS raw material are placed in a vacuum drying oven; In step S2: Add 30 parts of naphthenic rubber oil plasticizer and 2 parts of 1010 antioxidant, start stirring and heat up. When the temperature reaches 130°C, add the SIS elastomer mixture prepared in step S1, continue heating to 150°C, and maintain stirring for 30 minutes. In step S32: the temperature of the base colloid is adjusted to 140℃, 3 parts of γ-aminopropyltriethoxysilane dynamic crosslinking agent are added; then 50 parts of grafted modified C5 petroleum resin thickening resin are added, the mixture is stirred at 100 rpm for 10 minutes, and 0.6 parts of dibutyltin dilaurate catalyst are added. In step S42: Use a low speed of 50 rpm to stir and mix for 5 minutes.

[0031] Comparative Example 1 The preparation method is the same as in Example 1, but instead of using epoxidized SIS and star-shaped SIS in step S1, an equal amount of conventional linear SIS is used. The remaining steps are the same.

[0032] Comparative Example 2 The preparation method is the same as in Example 1, but the γ-aminopropyltriethoxysilane dynamic crosslinking agent is not added in step S32. The remaining steps are the same.

[0033] Comparative Example 3 The preparation method of Example 1 is followed, but instead of using grafted modified C5 petroleum resin tackifying resin, an equal amount of ordinary C5 petroleum resin is used, i.e., operation S31 is omitted. The remaining steps are the same.

[0034] Experimental Example 1 The mixture from Example 1, immediately after the addition of "γ-aminopropyltriethoxysilane dynamic crosslinking agent" and "grafted modified C5 petroleum resin," but before the addition of "di-n-butyltin dilaurate catalyst" and before the prolonged high-temperature vacuum reaction, was used as a reference sample. This sample was coated onto an ATR crystal, and its background spectrum was collected and denoted as A. Ref The final "crosslinked colloid" product, which underwent high-temperature drying at 135℃ for 30 minutes under vacuum and the action of a catalyst, was used as the target sample. This sample was coated onto an ATR crystal, and its spectrum was collected and denoted as A. Sample The samples were subjected to Fourier transform infrared spectroscopy at room temperature and a relative humidity of 40-50%, with a spectral range of 4000 cm⁻¹. -1 Up to 400cm -1 4cm resolution -1 The scan was performed 32 times; difference spectral processing was conducted, and calculations were performed using spectral software. (Where k is the correction factor, usually close to 1), the test results are as follows: Figure 2 As shown: At 1050-1100cm -1 The presence of a significant broad peak enhancement nearby is characteristic of Si-O-Si asymmetric stretching vibrations, confirming the "dynamic crosslinking" mechanism described in the technical solution. This mechanism involves the silane coupling agent forming a three-dimensional network structure between the SIS elastomer and resin through hydrolysis-condensation reactions under high temperature and catalysis. (See figure 950 cm⁻¹). -1 The downward indentation at this point, with a negative absorbance difference, indicates that the chemical groups corresponding to this band are reduced or disappeared after the reaction. This corresponds to the vibrational peak of Si-OC in the silane coupling agent. The ethoxy group in the KH-550 molecule undergoes hydrolysis and de-alcoholization during the reaction, transforming into silanol, which then condenses.

[0035] Experiment Example 2 The label adhesives prepared in both Examples 1-3 and Comparative Examples 1-3 were tested for their overall performance. Low-temperature initial tack test: Refer to standard GB / T 31125-2014 "Test method for initial tack of adhesive tape - ring method". After placing the sample and the object to be bonded (stainless steel plate) in a constant temperature chamber at -38℃ for 2 hours, the test is carried out. The result is indicated by "#" (the larger the ball number, the stronger the initial tack). Peel strength test: According to standard GB / T 2792-2014 "Test method for peel strength of adhesive tape", the adhesive film was adhered to the stainless steel plate and cured at -38℃ for 24 hours. Then, a 180° peel test was carried out at 300mm / min in an environment of -38℃. Moisture resistance cold bonding test: Simulate a high humidity condensation environment. The adhesive film is adhered to a clean glass plate and placed in a circulating temperature chamber ranging from -38℃ to 25℃ for 4 hours per cycle, with humidity >95%. After 72 hours, it is evaluated whether peeling, detachment, or obvious whitening (moisture intrusion) occurs. The test results are shown in Table 2. Table 2 Comparison of comprehensive performance test results between Examples 1-3 and Comparative Examples 1-3

[0036] The results show that Comparative Example 1, using ordinary linear SIS, exhibited severely deteriorated low-temperature performance, with a significant decrease in both initial tack and peel strength. This indicates that linear SIS lacks flexibility at low temperatures and has poor compatibility with the tackifying resin, resulting in unstable and poor bonding performance, slight edge lifting, and localized whitening of the adhesive layer. Comparative Example 2, lacking dynamic crosslinking, showed low peel strength and significant failure in the damp-cold resistance test. This demonstrates the lack of a dynamic crosslinking network, resulting in insufficient cohesion within the adhesive and an inability to balance the contradiction between low-temperature initial tack and room-temperature tack. It also confirms the crucial role of dynamic crosslinking in improving structural stability. Comparative Example 3, using ordinary tackifying resin, exhibited poor initial tack and peel strength, with partial lifting and whitening. This suggests that ordinary resin is prone to compatibility issues with the matrix or is itself hydrophilic in high-humidity environments, leading to performance degradation.

Claims

1. A label adhesive for use in freezing environments, comprising a base colloid, a crosslinking agent, and a tackifying resin, characterized in that, The base colloid is composed of a mixture of cycloalkyl rubber oil plasticizer, 1010 antioxidant, and SIS elastomer; the SIS elastomer mixture is composed of a mixture of epoxidized styrene-isoprene-styrene copolymer and star-shaped SIS; the crosslinking agent is a γ-aminopropyltriethoxysilane dynamic crosslinking agent, which can perform in-situ crosslinking modification on the SIS elastomer mixture to form a three-dimensional network structure; the tackifying resin is a graft-modified C5 petroleum resin tackifying resin, which is modified by grafting C5 petroleum resin with acrylate monomers.

2. The label adhesive for freezing environments according to claim 1, characterized in that, The amount of each component in the label adhesive is as follows: 10-20 parts of epoxidized styrene-isoprene-styrene copolymer, 10-20 parts of star-shaped SIS, 20-30 parts of naphthenic rubber oil plasticizer, 1-2 parts of 1010 antioxidant, 1-3 parts of γ-aminopropyltriethoxysilane dynamic crosslinking agent, 40-50 parts of grafted modified C5 petroleum resin tackifying resin, and 0.4-0.6 parts of dibutyltin dilaurate catalyst additive.

3. A method for preparing a label adhesive for freezing environments according to any one of claims 1-2, characterized in that, S1: The epoxidized styrene-isoprene-styrene copolymer and the star-shaped SIS raw material are dried to fully remove the adsorbed moisture, and then mixed to obtain a SIS elastomer mixture. S2: Add cycloalkyl rubber oil plasticizer and 1010 antioxidant to a stainless steel reactor, start stirring and heat up, add the SIS elastomer mixture prepared in step S1, continue heating and stirring to obtain the basic colloid; S31: Add 30 parts of C5 petroleum resin, 20 parts of butyl acrylate monomer, and 0.5 parts of dicumyl peroxide initiator to a reaction vessel, heat and react to obtain grafted modified C5 petroleum resin tackifying resin. S32: Adjust the temperature of the base colloid, add γ-aminopropyltriethoxysilane dynamic crosslinking agent, stir for 5 minutes, then add grafted modified C5 petroleum resin thickening resin, stir, then vacuum dry, and finally add dibutyltin dilaurate catalyst to obtain crosslinked colloid. S4: Cool the cross-linked colloid to 80°C, stop heating, seal the feeding port, start the vacuum pump to degas the colloid in the reactor for 10 minutes, pour out the degassed colloid while it is still hot, calender it through a cooling metal roller press, adjust the roller gap to press the colloid into a film, cool and cure it to obtain the label adhesive of the present invention.

4. The method for preparing a label adhesive for freezing environments according to claim 3, characterized in that, The drying process described in step S1 specifically involves vacuum drying at 60°C for 2 hours.

5. A method for preparing a label adhesive for freezing environments according to claim 3, characterized in that, The heating mentioned in step S2 specifically refers to the temperature rising to 120℃~130℃.

6. The method for preparing a label adhesive for freezing environments according to claim 3, characterized in that, The heating and stirring described in step S2 specifically involves heating to 140°C to 150°C and maintaining stirring for 30 to 60 minutes.

7. A method for preparing a label adhesive for freezing environments according to claim 3, characterized in that, The heating reaction described in step S31 specifically involves heating to 130°C and stirring the reaction for 2 hours under nitrogen protection.

8. A method for preparing a label adhesive for freezing environments according to claim 3, characterized in that, The adjustment of the base colloid temperature mentioned in step S32 specifically refers to adjusting the base colloid temperature to 130℃~140℃.

9. A method for preparing a label adhesive for freezing environments according to claim 3, characterized in that, The stirring described in step S32 specifically involves stirring at a speed of 60-100 rpm for 10-20 minutes.

10. A method for preparing a label adhesive for freezing environments according to claim 3, characterized in that, The vacuum drying described in step S32 specifically involves drying at 135°C for 30 minutes under vacuum.

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