Hot-melt pressure-sensitive adhesive and preparation method therefor, and label product

Abstract

The present invention relates to the technical field of adhesives, particularly to a hot-melt pressure-sensistive adhesive and a preparation method therefor, and a label product. The hot-melt pressure-sensitive adhesive comprises the following components in parts by weight: 15-25 parts of a diluent, 15-35 parts of a styrene block copolymer, 2.5-6 parts of an ethylene-acrylic acid copolymer, 35-55 parts of a hydrogenated rosin resin, and 0.2-2 parts of an antioxidant, wherein the acid value of the hydrogenated rosin resin is greater than or equal to 150 mg KOH / g. The hot-melt pressure-sensitive adhesive of the present application exhibits good adhesion, thermal stability and aging resistance, and is environmentally friendly. The label product prepared from the hot-melt pressure-sensitive adhesive of the present application can be detached from an adherend within 5 min (or even as fast as within 1 min) after alkaline washing, which helps to implement the process of automated container recycling.

Description

Hot melt pressure-sensitive adhesive, its preparation method and label products Technical Field

[0001] This application relates to the field of adhesive technology, and in particular to a hot melt pressure-sensitive adhesive, its preparation method, and label products. Background Technology

[0002] Labels are widely used in daily life for various items, documents, packages, etc., to provide relevant information or for classification. Alkali-washable labels are a special type of label primarily used for the recycling of items such as containers. With ordinary labels, it is difficult to separate the label from the container during recycling, which is detrimental to the cleanliness of the recycled container. Containers with alkali-washable labels, after being soaked in alkaline water under certain conditions, will have their labels automatically detach from the container, enabling automated container recycling and promoting the sustainable development of packaging materials.

[0003] Currently, commercially available washable labels primarily use water-based acrylic or solvent-based acrylic adhesives. However, due to environmental concerns, manufacturing costs, and mechanical performance considerations, hot-melt pressure-sensitive adhesives are increasingly being used on containers such as water bottles and beverage bottles. However, hot-melt pressure-sensitive adhesives are primarily composed of rubber and mineral oil, making them generally hydrophobic and difficult to separate from the container in alkaline water.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0006] The purpose of this application is to provide a hot melt pressure-sensitive adhesive, its preparation method, and label products. Compared with water-based and solvent-based acrylic systems, the hot melt pressure-sensitive adhesive of this application has the characteristics of being environmentally friendly, low-cost, having excellent adhesion performance and aging resistance, and is also hydrophilic, which can enable the label to separate from the object being applied in alkaline water.

[0007] To achieve the above objectives, the first aspect of this application provides a hot melt pressure-sensitive adhesive, comprising the following components in parts by weight:

[0008] The ingredients are: 15-25 parts diluent, 15-35 parts styrene block copolymer, 2.5-6 parts ethylene-acrylic acid copolymer, 35-55 parts hydrogenated rosin resin, and 0.2-2 parts antioxidant.

[0009] The acid value of the hydrogenated rosin resin is ≥150mg KOH / g.

[0010] In a specific embodiment of this application, the acid value of the hydrogenated rosin resin is 150-210 mg KOH / g.

[0011] In a specific embodiment of this application, the acrylic acid content in the ethylene-acrylic acid copolymer is ≥10wt%.

[0012] In a specific embodiment of this application, the mass ratio of the ethylene-acrylic acid copolymer to the styrene block copolymer is 1:(5-10).

[0013] In a specific embodiment of this application, the diluent includes mineral oil.

[0014] In specific embodiments of this application, the styrene block copolymer includes at least one of styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene / butene-styrene block copolymer, and styrene-ethylene / propylene-styrene block copolymer.

[0015] In specific embodiments of this application, the antioxidant includes at least one of hindered phenolic antioxidants, phosphite antioxidants, and dithiopropyl thioester antioxidants.

[0016] The second aspect of this application provides a method for preparing the hot melt pressure-sensitive adhesive of the first aspect of this application, comprising the following steps: mixing and stirring a styrene block copolymer, an antioxidant and a diluent at 160-170°C, then adding an ethylene-acrylic acid copolymer and hydrogenated rosin resin, and mixing and stirring at 140-160°C to obtain the hot melt pressure-sensitive adhesive.

[0017] A third aspect of this application provides a label article, including a label body and a hot melt pressure-sensitive adhesive layer disposed on the label body; the hot melt pressure-sensitive adhesive layer is mainly made of the hot melt pressure-sensitive adhesive provided in the first aspect of this application.

[0018] In a specific embodiment of this application, the label article further includes a release film layer; the release film layer is disposed on the surface of the hot melt pressure-sensitive adhesive layer away from the label body.

[0019] Compared with the prior art, the beneficial effects of this application are as follows:

[0020] (1) The hot melt pressure-sensitive adhesive of this application is formulated with diluent, styrene block copolymer, ethylene-acrylic acid copolymer, hydrogenated rosin resin, etc. It has excellent adhesion, thermal stability and aging resistance, and good environmental protection. At the same time, it can quickly lose its tack under alkaline water conditions to achieve separation between the label and the object being applied.

[0021] (2) The label products made with the hot melt pressure-sensitive adhesive of this application are alkali washable labels that can be separated from the object within 5 minutes (as fast as 1 minute) after alkali washing, which is conducive to realizing the automated container recycling process, and the label products have good die-cutting properties.

[0022] After reading and understanding the detailed description, other aspects can be understood. Detailed Implementation

[0023] The technical solution of this application will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this application, not all embodiments, and are only used to illustrate this application, and should not be regarded as limiting the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0024] Water-based and solvent-based acrylic pressure-sensitive adhesives used for alkaline washable labels exhibit poor adhesion, particularly to non-polar surfaces or containers, where their adhesion is inferior to rubber-based hot-melt pressure-sensitive adhesives. If acrylic pressure-sensitive adhesives need to be applied to non-polar surfaces such as PP or PE films, the surface must undergo corona treatment before application, increasing costs and processing steps. Traditional rubber-based hot-melt pressure-sensitive adhesives also show poor separation performance in alkaline water. Therefore, developing a hot-melt pressure-sensitive adhesive that combines environmental friendliness, strong adhesion, and alkaline washability is crucial for the application of alkaline washable labels.

[0025] The first aspect of this application provides a hot melt pressure-sensitive adhesive, comprising the following components by weight: 15-25 parts of diluent, 15-35 parts of styrene block copolymer, 2.5-6 parts of ethylene-acrylic acid copolymer, 35-55 parts of hydrogenated rosin resin, and 0.2-2 parts of antioxidant;

[0026] The acid value of hydrogenated rosin resin is ≥150mg KOH / g.

[0027] The hot melt pressure-sensitive adhesive of this application is formulated with diluent, styrene block copolymer, ethylene-acrylic acid copolymer, hydrogenated rosin resin and other ingredients. It has excellent adhesion, thermal stability and aging resistance, and is environmentally friendly. At the same time, it can quickly lose its tack under alkaline water conditions, so as to achieve separation between the label and the object being applied.

[0028] In different implementation methods, the amounts of each component in the hot melt pressure-sensitive adhesive, by weight, can be as follows:

[0029] The amount of diluent can be 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, or any combination thereof;

[0030] The amount of styrene block copolymer can be 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, or any combination thereof;

[0031] The amount of ethylene-acrylic acid copolymer can be 3 parts, 4 parts, 5 parts, 6 parts, or any combination thereof;

[0032] The amount of hydrogenated rosin resin can be 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, or any combination thereof.

[0033] The amount of antioxidant can be 0.2 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, or any combination thereof.

[0034] This application uses a high-acid-value hydrogenated rosin resin, which enables the hot-melt pressure-sensitive adhesive to react rapidly with alkaline water, causing the adhesive to lose its tack and water to seep into the label bonding interface, causing the substrate to curl and detach. For example, the acid value of the hydrogenated rosin resin can be within the range of 150 mg KOH / g, 160 mg KOH / g, 170 mg KOH / g, 180 mg KOH / g, 190 mg KOH / g, 200 mg KOH / g, 210 mg KOH / g, 220 mg KOH / g, 230 mg KOH / g, 240 mg KOH / g, 250 mg KOH / g, or any combination thereof. The inventors of this application further discovered that when the acid value of the hydrogenated rosin resin is too high, it leads to a decrease in the aging resistance and yellowing resistance of the hot-melt pressure-sensitive adhesive. Furthermore, the acid value of hydrogenated rosin resin is 150-210 mg KOH / g, which helps to balance the alkaline washability, aging resistance, and yellowing resistance of hot melt pressure-sensitive adhesive.

[0035] This application uses hydrogenated rosin resin, which can significantly improve the thermal stability and aging resistance of hot melt pressure-sensitive adhesive while ensuring its bonding performance.

[0036] In a specific embodiment of this application, the acrylic acid content in the ethylene-acrylic acid copolymer is ≥10wt%, for example, it can be 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, or any combination thereof. The ethylene-acrylic acid copolymer is a copolymer of ethylene and acrylic acid. Acrylic acid contains carboxyl groups, is a hydrophilic material, and has a certain degree of solubility in alkaline water. The addition of the ethylene-acrylic acid copolymer can improve the overall hydrophilicity of the hot melt adhesive, facilitating the rapid entry of alkaline water into the bonding interface, causing the hot melt pressure-sensitive adhesive to lose tack upon contact with alkaline water while the substrate curls, promoting the separation of the label and the adhered object. Further controlling the acrylic acid content in the ethylene-acrylic acid copolymer within the above-mentioned range further helps to improve the hydrophilicity, adhesion, and die-cutting performance of the hot melt pressure-sensitive adhesive. Improved die-cutting performance can solve the problem of poor die-cutting properties of film labels.

[0037] In a specific embodiment of this application, the mass ratio of ethylene-acrylic acid copolymer to styrene block copolymer is 1:(5-10), for example, it can be a range of 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, or any combination thereof, thereby helping to improve washability, adhesion, and die-cutting properties. When the amount of ethylene-acrylic acid copolymer is too high, causing its mass ratio to styrene block copolymer to exceed the above range, the initial ring tack of the corresponding hot melt pressure-sensitive adhesive decreases, and the surface tack decreases; when the amount of ethylene-acrylic acid copolymer is too low, causing its mass ratio to styrene block copolymer to exceed the above range, it leads to poor alkaline washability and relatively poor die-cutting properties.

[0038] In a specific embodiment of this application, the diluent includes mineral oil.

[0039] In specific embodiments of this application, the styrene block copolymer includes at least one of styrene-isoprene-styrene (SIS) block copolymer, styrene-butadiene-styrene (SBS) block copolymer, styrene-ethylene / butene-styrene (SEBS) block copolymer, and styrene-ethylene / propylene-styrene (SEPS) block copolymer.

[0040] In specific embodiments of this application, the antioxidant includes at least one of hindered phenolic antioxidants, phosphite antioxidants, and dipropyl thioester antioxidants. For example, antioxidant 1010 and antioxidant 168 can be combined, but are not limited thereto. The mass ratio of antioxidant 1010 to antioxidant 168 is 1:1.

[0041] The second aspect of this application provides a method for preparing the hot melt pressure-sensitive adhesive of the first aspect of this application, comprising the following steps: mixing and stirring a styrene block copolymer, an antioxidant and a diluent at 160-170°C, then adding an ethylene-acrylic acid copolymer and hydrogenated rosin resin, and mixing and stirring at 140-160°C to obtain the hot melt pressure-sensitive adhesive.

[0042] In a specific embodiment of this application, the mixture is stirred at 160–170°C for 30–50 minutes and then evacuated.

[0043] In a specific embodiment of this application, the mixture is vacuum-mixed and stirred at 140–160°C for 40–60 minutes.

[0044] In a specific embodiment of this application, the method further includes: applying a hot melt pressure-sensitive adhesive to the surface of a substrate. Further, the coating temperature is 150–170°C; the coating basis weight is 10–25 gsm.

[0045] The third aspect of this application provides a label article, including a label body and a hot melt pressure-sensitive adhesive layer disposed on the label body; the hot melt pressure-sensitive adhesive layer is mainly made of the hot melt pressure-sensitive adhesive provided in the first aspect of this application.

[0046] In a specific embodiment of this application, the label article further includes a release film layer; the release film layer is disposed on the surface of the hot melt pressure-sensitive adhesive layer away from the label body. During application, the release film layer is removed, and the label is then applied.

[0047] Example 1

[0048] This embodiment provides a hot melt pressure-sensitive adhesive, comprising the following components in parts by weight:

[0049] 21 parts diluent, 21 parts styrene block copolymer, 4 parts ethylene-acrylic acid copolymer, 54 parts hydrogenated rosin resin and 1 part antioxidant.

[0050] The diluent is mineral oil N4010 (manufacturer: Guangzhou Dagang Petroleum Technology Co., Ltd.), the styrene block copolymer is SIS (manufacturer: Yueyang Baling Petrochemical Co., Ltd.), the ethylene-acrylic acid copolymer is ESCOR EAA5200 (acrylic acid content 15%, manufacturer: ExxonMobil, USA), the hydrogenated rosin resin is hydrogenated rosin resin KHR75 (acid value 160-180 mg KOH / g, manufacturer: Guangdong Kemao Forestry Chemical Co., Ltd.), and the antioxidants are antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0051] The preparation method of the hot melt pressure-sensitive adhesive in this embodiment includes the following steps:

[0052] (1) Styrene block copolymer, antioxidant and diluent are mixed and stirred at 165°C for 40 min and then vacuumed.

[0053] (2) Add ethylene-acrylic acid copolymer and hydrogenated rosin resin to the material obtained in step (1), and then stir under vacuum at 150°C for 50 min.

[0054] (3) Coat the material obtained in step (2) onto the PET substrate at a coating temperature of 160°C and a coating weight of 20 gsm, and then roll it up for later use.

[0055] Example 2

[0056] This embodiment refers to the hot melt pressure-sensitive adhesive and its preparation method in Example 1, the only difference being that the amount of each component in the hot melt pressure-sensitive adhesive is different.

[0057] The hot melt pressure-sensitive adhesive of this embodiment includes the following components by weight: 22 parts diluent, 26 parts styrene block copolymer, 4 parts ethylene-acrylic acid copolymer, 48 parts hydrogenated rosin resin and 1 part antioxidant.

[0058] Example 3

[0059] This embodiment refers to the hot melt pressure-sensitive adhesive and its preparation method in Example 1, the only difference being that the amount of each component in the hot melt pressure-sensitive adhesive is different.

[0060] The hot melt pressure-sensitive adhesive of this embodiment includes the following components by weight: 22 parts diluent, 27 parts styrene block copolymer, 3 parts ethylene-acrylic acid copolymer, 48 parts hydrogenated rosin resin, and 1 part antioxidant.

[0061] Example 4

[0062] This embodiment refers to the hot melt pressure-sensitive adhesive and its preparation method in Example 1, the only difference being that the amount of each component in the hot melt pressure-sensitive adhesive is different.

[0063] The hot melt pressure-sensitive adhesive of this embodiment includes the following components by weight: 14 parts diluent, 35 parts styrene block copolymer, 4 parts ethylene-acrylic acid copolymer, 47 parts hydrogenated rosin resin and 1 part antioxidant.

[0064] Example 5

[0065] This embodiment refers to the hot melt pressure-sensitive adhesive and its preparation method in Example 1, the only difference being that the amount of each component in the hot melt pressure-sensitive adhesive is different.

[0066] The hot melt pressure-sensitive adhesive of this embodiment includes the following components by weight: 24 parts diluent, 35 parts styrene block copolymer, 6 parts ethylene-acrylic acid copolymer, 35 parts hydrogenated rosin resin, and 1 part antioxidant.

[0067] Example 6

[0068] This embodiment refers to the hot melt pressure-sensitive adhesive and its preparation method in Embodiment 2, the only difference being that the type of hydrogenated rosin resin is different.

[0069] The hydrogenated rosin resin in this embodiment is hydrogenated rosin resin H120F (acid value > 210 mg KOH / g and ≤ 265 mg KOH / g, manufactured by Guangdong Kemao Forestry Chemical Co., Ltd.).

[0070] Example 7

[0071] This embodiment refers to the hot melt pressure-sensitive adhesive and its preparation method in Example 2, the only difference being that the type of ethylene-acrylic acid copolymer is different.

[0072] The ethylene-acrylic acid copolymer in this embodiment is ESCOR EAA5000 (acrylic acid content 6%, manufactured by ExxonMobil, USA).

[0073] Example 8

[0074] This embodiment refers to the hot melt pressure-sensitive adhesive and its preparation method in Embodiment 2, the only difference being that the amount of each component in the hot melt pressure-sensitive adhesive is different.

[0075] The hot melt pressure-sensitive adhesive of this embodiment includes the following components by weight: 22 parts diluent, 24 parts styrene block copolymer, 6 parts ethylene-acrylic acid copolymer, 48 parts hydrogenated rosin resin, and 1 part antioxidant.

[0076] Example 9

[0077] This embodiment refers to the hot melt pressure-sensitive adhesive and its preparation method in Embodiment 2, the only difference being that the amount of each component in the hot melt pressure-sensitive adhesive is different.

[0078] The hot melt pressure-sensitive adhesive of this embodiment includes the following components by weight: 22 parts diluent, 27.5 parts styrene block copolymer, 2.5 parts ethylene-acrylic acid copolymer, 48 parts hydrogenated rosin resin, and 1 part antioxidant.

[0079] Comparative Example 1

[0080] Comparative Example 1 refers to the hot melt pressure-sensitive adhesive and its preparation method in Example 2, the difference being that the type of hydrogenated rosin resin is different.

[0081] The hydrogenated rosin resin of Comparative Example 1 was hydrogenated rosin resin KA100W (acid value ≤30mg KOH / g, manufacturer: Guangdong Kemao Forestry Chemical Co., Ltd.).

[0082] Comparative Example 2

[0083] Comparative Example 2 refers to the hot melt pressure-sensitive adhesive and its preparation method in Example 2, the difference being that the amount of each component in the hot melt pressure-sensitive adhesive is different.

[0084] Comparative Example 2 hot melt pressure-sensitive adhesive comprises the following components by weight: 22 parts diluent, 40 parts styrene block copolymer, 4 parts ethylene-acrylic acid copolymer, 34 parts hydrogenated rosin resin, and 1 part antioxidant.

[0085] Comparative Example 3

[0086] Comparative Example 3 refers to the hot melt pressure-sensitive adhesive and its preparation method in Example 2, the difference being that the amount of each component in the hot melt pressure-sensitive adhesive is different.

[0087] The hot melt pressure-sensitive adhesive of Comparative Example 3 comprises the following components by weight: 22 parts diluent, 30 parts styrene block copolymer, 48 parts hydrogenated rosin resin and 1 part antioxidant.

[0088] Comparative Example 4

[0089] Comparative Example 4 refers to the hot melt pressure-sensitive adhesive and its preparation method in Example 2, except that: an equal weight of non-hydrogenated rosin resin 278L (acid value ≤170mg KOH / g, manufacturer: Guangdong Kemao Forestry Chemical Co., Ltd.) was used to replace the hydrogenated rosin resin in Example 2.

[0090] Experimental Example

[0091] To compare and illustrate the performance differences of the hot melt pressure-sensitive adhesives in different embodiments and comparative examples, the following tests were conducted, and the test results are shown in Table 1.

[0092] Peel strength: The PET samples prepared in each embodiment and comparative example were pasted onto steel plates, and the peel strength was tested according to GB / T 2792.

[0093] Peel strength after aging at 70℃ for 3 days: Prepare the mating samples as described above, place them at 70℃ for 3 days, and test the peel strength of the steel plate according to GB / T 2792.

[0094] Annular initial tack: The PET samples prepared in each embodiment and comparative example were tested for annular initial tack against steel plates according to GB / T 31125.

[0095] The effect of alkaline washing on PET bottles: Prepare a 5wt% NaOH aqueous solution and heat it to 80℃. Attach the PET sample to the PET bottle body. Cut the bottle body with the PET sample attached into square pieces of 1cm*1cm, put them into the alkaline solution and stir. Observe whether it falls off within 10 minutes and record the time of fall-off.

[0096] The effect of alkaline water washing on PET stickers on glass bottles: Prepare a 5wt% NaOH aqueous solution and heat it to 80℃. Attach the PET sticker to the glass bottle and immerse it in the alkaline water. Observe whether it falls off within 5 minutes and record the time of detachment.

[0097] Die-cutting performance: Approximately 500 meters of PET roll samples prepared in each example and comparative example were tested for die-cutting performance in a label die-cutting waste removal device to observe whether the die-cutting was smooth.

[0098] At a die-cutting speed of 100m / min, there is no sticking, no flying marks, and smooth and continuous waste removal, indicating excellent die-cutting performance;

[0099] At a die-cutting speed of 100m / min, there are 1 to 2 instances of adhesion or waste removal breakage. The die-cutting speed needs to be reduced to achieve no adhesion, no flying marks, and smooth and continuous waste removal. Its die-cutting performance is good.

[0100] If the number of adhesions or waste breakages exceeds 2 at a die-cutting speed of 100 m / min, its die-cutting performance is poor.

[0101] Table 1 Test results for different hot melt pressure-sensitive adhesives

[0102] According to the test results of the examples and Comparative Example 1, the hydrogenated rosin resin used in Comparative Example 1 has a relatively low acid value and cannot be separated in alkaline water. According to the test results of the examples and Comparative Example 2, the amount of hydrogenated rosin resin used in Comparative Example 2 is relatively small, and separation is also impossible in alkaline water. According to the test results of the examples and Comparative Example 3, Comparative Example 3 did not use ethylene-acrylic acid copolymer, resulting in lower peel strength, poor die-cutting properties, and slower separation speed in alkaline water for the corresponding hot melt pressure-sensitive adhesive. According to the test results of the examples and Comparative Example 4, the use of non-hydrogenated rosin resin instead of hydrogenated rosin resin in Comparative Example 4 significantly worsened the aging resistance of the corresponding hot melt pressure-sensitive adhesive.

[0103] The test results above show that the hot melt pressure-sensitive adhesive of this application has excellent adhesion (peel strength ≥15N / inch, initial tack ≥15N / inch), thermal stability and aging resistance, and is environmentally friendly. At the same time, it can quickly lose tack under alkaline water conditions, so as to separate the label from the object being labeled, which helps to realize the automated container recycling process.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A hot melt pressure-sensitive adhesive, comprising the following components in parts by weight: The ingredients are: 15-25 parts diluent, 15-35 parts styrene block copolymer, 2.5-6 parts ethylene-acrylic acid copolymer, 35-55 parts hydrogenated rosin resin, and 0.2-2 parts antioxidant. The acid value of the hydrogenated rosin resin is ≥150mg KOH / g.

2. The hot melt pressure-sensitive adhesive according to claim 1, wherein, The acid value of the hydrogenated rosin resin is 150-210 mg KOH / g.

3. The hot melt pressure-sensitive adhesive according to claim 1, wherein, The ethylene-acrylic acid copolymer contains ≥10wt% acrylic acid.

4. The hot melt pressure-sensitive adhesive according to claim 1, wherein, The mass ratio of the ethylene-acrylic acid copolymer to the styrene block copolymer is 1:(5-10).

5. The hot melt pressure-sensitive adhesive according to claim 1, wherein, The diluent includes mineral oil.

6. The hot melt pressure-sensitive adhesive according to claim 1, wherein, The styrene block copolymer includes at least one of styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene / butene-styrene block copolymer, and styrene-ethylene / propylene-styrene block copolymer.

7. The hot melt pressure-sensitive adhesive according to claim 1, wherein, The antioxidant includes at least one of hindered phenolic antioxidants, phosphite antioxidants, and dithiopropyl thioester antioxidants.

8. A method for preparing the hot melt pressure-sensitive adhesive according to any one of claims 1 to 7, comprising the following steps: mixing and stirring a styrene block copolymer, an antioxidant, and a diluent at 160 to 170°C, then adding an ethylene-acrylic acid copolymer and hydrogenated rosin resin, and mixing and stirring at 140 to 160°C to obtain the hot melt pressure-sensitive adhesive.

9. A label product comprising a label body and a hot-melt pressure-sensitive adhesive layer disposed on the label body, wherein, The hot melt pressure-sensitive adhesive layer is mainly made of the hot melt pressure-sensitive adhesive as described in any one of claims 1 to 7.

10. The label article according to claim 9, wherein, The label product further includes a release film layer; the release film layer is disposed on the surface of the hot melt pressure-sensitive adhesive layer away from the label body.

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