Hot melt pressure sensitive adhesive and preparation method thereof and label product

Abstract

The present invention relates to the field of adhesive technology, and in particular to a hot melt pressure-sensitive adhesive, a preparation method thereof, and a label product. The hot melt pressure-sensitive adhesive comprises the following components in parts by weight: 14 to 25 parts of a diluent, 15 to 35 parts of a styrene block copolymer, 2.5 to 6 parts of an ethylene-acrylic acid copolymer, 35 to 55 parts of a hydrogenated rosin resin, and 0.2 to 2 parts of an antioxidant; the acid value of the hydrogenated rosin resin is ≥150 mg KOH / g. The hot melt pressure-sensitive adhesive of the present invention has excellent adhesion, thermal stability, and aging resistance, and is environmentally friendly; the label product prepared by the hot melt pressure-sensitive adhesive of the present invention can be detached from the adhered object within 5 minutes (the fastest can be within 1 minute) after washing with alkaline water, which is conducive to realizing an automated container recycling process.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, in particular to a hot-melt pressure-sensitive adhesive and a preparation method thereof and a label product. Background Art

[0002] Labels are widely used in daily life and are used on various items, documents, packages, etc. to provide relevant information or for classification. Alkaline washable separation labels are a special type of label, mainly used for the recycling of items such as containers. When ordinary labels are used to recycle containers, it is difficult to separate the labels from the containers, which is not conducive to the cleanliness of container recycling. When a container with an alkali washable separation label is immersed in alkaline water under certain conditions, the label will automatically fall off and separate from the container, which can realize automatic container recycling and is conducive to the sustainable development of packaging materials.

[0003] Currently, the commercially available adhesives for alkali-washable separation labels are mainly water-based acrylic or solvent-based acrylic systems. However, due to environmental protection, manufacturing costs, and mechanical properties, more and more containers such as water bottles and beverage bottles are using hot melt pressure-sensitive adhesive labels. However, the main materials of hot melt pressure-sensitive adhesives are rubber and mineral oil, which are hydrophobic materials as a whole, making it difficult to separate labels and containers in alkaline water.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a hot melt pressure-sensitive adhesive and a preparation method thereof and a label product. Compared with water-based and solvent-based acrylic systems, the hot melt pressure-sensitive adhesive of the present invention has the characteristics of environmental protection, low cost, excellent bonding performance and aging resistance, and is hydrophilic, which can realize the separation of the label from the adhered object in alkaline water.

[0006] In order to achieve the above-mentioned object of the present invention, the first aspect of the present invention provides a hot melt pressure-sensitive adhesive, comprising the following components in parts by weight:

[0007] 14-25 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;

[0008] The acid value of the hydrogenated rosin resin is ≥150 mg KOH / g.

[0009] In a specific embodiment of the present invention, the acid value of the hydrogenated rosin resin is 150-210 mg KOH / g.

[0010] In a specific embodiment of the present invention, the content of acrylic acid in the ethylene-acrylic acid copolymer is ≥10wt%.

[0011] In a specific embodiment of the present invention, the mass ratio of the ethylene-acrylic acid copolymer to the styrene block copolymer is 1:(5-10).

[0012] In a particular embodiment of the present invention, the diluent comprises mineral oil.

[0013] In a specific embodiment of the present invention, the styrene block copolymer includes at least one of styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene / butylene-styrene block copolymer and styrene-ethylene / propylene-styrene block copolymer.

[0014] In a specific embodiment of the present invention, the antioxidant includes at least one of a hindered phenol antioxidant, a phosphite antioxidant and a dipropyl thioate antioxidant.

[0015] The second aspect of the present invention provides a method for preparing the hot melt pressure-sensitive adhesive of the first aspect of the present invention, 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 a hydrogenated rosin resin, and mixing and stirring at 140-160°C to obtain a hot melt pressure-sensitive adhesive.

[0016] The third aspect of the present invention provides a label product, comprising 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 by the first aspect of the present invention.

[0017] In a specific embodiment of the present invention, the label product further comprises a release film layer; the release film layer is arranged on a surface of the hot-melt pressure-sensitive adhesive layer away from the label body.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The hot melt pressure-sensitive adhesive of the present invention is compounded with a diluent, a styrene block copolymer, an ethylene-acrylic acid copolymer, a hydrogenated rosin resin, etc., and has excellent adhesion, thermal stability and aging resistance, and is environmentally friendly. At the same time, it can quickly lose adhesion under alkaline water conditions to achieve separation between the label and the adhered object;

[0020] (2) The label product made of the hot-melt pressure-sensitive adhesive of the present invention is an alkali-washable detachable label, which can be detached from the adhered object within 5 minutes (or as fast as within 1 minute) after alkali-washing, which is conducive to realizing an automated container recycling process, and the label product has good die-cutting properties. DETAILED DESCRIPTION

[0021] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0022] The water-based and solvent-based acrylic pressure-sensitive adhesives used for alkali-washable separation labels have poor adhesion, especially for non-polar surface materials or non-polar containers, the adhesion is not as good as rubber-type hot-melt pressure-sensitive adhesives. If acrylic pressure-sensitive adhesives need to be coated on non-polar surface materials such as PP and PE films, the surface materials need to be corona treated before coating, which increases costs and processes. Traditional rubber-type hot-melt pressure-sensitive adhesives do not have a good separation effect in alkaline water. Based on this, how to provide a hot-melt pressure-sensitive adhesive that is environmentally friendly, has good adhesion, and is alkali-washable is of great significance for the application of alkali-washable separation labels.

[0023] The first aspect of the present invention provides a hot melt pressure-sensitive adhesive, comprising the following components by weight: 14 to 25 parts of a diluent, 15 to 35 parts of a styrene block copolymer, 2.5 to 6 parts of an ethylene-acrylic acid copolymer, 35 to 55 parts of a hydrogenated rosin resin, and 0.2 to 2 parts of an antioxidant;

[0024] The acid value of hydrogenated rosin resin is ≥150mg KOH / g.

[0025] The hot melt pressure sensitive adhesive of the present invention is compounded with diluent, styrene block copolymer, ethylene-acrylic acid copolymer, hydrogenated rosin resin and the like, has excellent adhesion, thermal stability and aging resistance, and is environmentally friendly. It can also quickly lose adhesion under alkaline water conditions to achieve separation between the label and the adhered object.

[0026] For example, in different embodiments, the amounts of the components in the hot melt pressure sensitive adhesive may be as follows, measured by weight:

[0027] The amount of the diluent can be 14 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts or a range consisting of any two of them;

[0028] The amount of the styrene block copolymer can be 15 parts, 20 parts, 25 parts, 30 parts, 35 parts or any two thereof;

[0029] The amount of ethylene-acrylic acid copolymer can be 3 parts, 4 parts, 5 parts, 6 parts or any two parts thereof;

[0030] The amount of hydrogenated rosin resin can be 35 parts, 40 parts, 45 parts, 50 parts, 55 parts or a range consisting of any two of them;

[0031] The amount of the antioxidant can be 0.2 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts or a range consisting of any two of them.

[0032] The present invention adopts hydrogenated rosin resin with high acid value, which can make the hot melt pressure-sensitive adhesive react with alkaline water quickly, so that the adhesive loses viscosity, and water penetrates into the label bonding interface to make the substrate curl and fall off. For example, the acid value of the hydrogenated rosin resin can be 150mgKOH / g, 160mg KOH / g, 170mg KOH / g, 180mg KOH / g, 190mg KOH / g, 200mg KOH / g, 210mg KOH / g, 220mg KOH / g, 230mg KOH / g, 240mg KOH / g, 250mg KOH / g or a range consisting of any two of them. The inventor of the present invention further studied and found that when the acid value of the hydrogenated rosin resin is too high, the aging resistance and yellowing resistance of the hot melt pressure-sensitive adhesive will decrease. Furthermore, the acid value of the hydrogenated rosin resin is 150-210 mg KOH / g, which helps to take into account the alkali water washability, aging resistance and yellowing resistance of the hot melt pressure-sensitive adhesive.

[0033] The invention adopts hydrogenated rosin resin to ensure the bonding performance of the hot melt pressure sensitive adhesive and can significantly improve the thermal stability and aging resistance of the hot melt pressure sensitive adhesive.

[0034] In a specific embodiment of the present invention, in the ethylene-acrylic acid copolymer, the content of acrylic acid is ≥10wt%, for example, it can be 10wt%, 12wt%, 15wt%, 18wt%, 20wt% or a range consisting of any two of them. 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 solubility in alkaline water. The addition of ethylene-acrylic acid copolymer can improve the hydrophilicity of the overall hot melt adhesive, help alkaline water to quickly enter the bonding interface, make the hot melt pressure-sensitive adhesive lose adhesion when in contact with alkaline water, and curl the substrate, thereby promoting the separation of the label and the object to be attached. Further regulating the content of acrylic acid in the ethylene-acrylic acid copolymer within the above range is more conducive to taking into account the improvement of the hydrophilicity, adhesion and die-cutting performance of the hot melt pressure-sensitive adhesive. The improvement of die-cutting performance can solve the problem of poor die-cutting properties of film labels.

[0035] In a specific embodiment of the present invention, the mass ratio of ethylene-acrylic acid copolymer to styrene block copolymer is 1: (5-10), for example, it can be 1: 5, 1: 6, 1: 7, 1: 8, 1: 9, 1: 10 or any two of them, which helps to improve the water washability, adhesion and die cuttability. When the amount of ethylene-acrylic acid copolymer is too high, so that the mass ratio of it to styrene block copolymer exceeds the above range, the corresponding ring initial adhesion of the hot melt pressure-sensitive adhesive decreases, and the surface viscosity decreases; when the amount of ethylene-acrylic acid copolymer is too low, so that the mass ratio of it to styrene block copolymer exceeds the above range, it will lead to poor alkali water washability and relatively poor die cuttability.

[0036] In a particular embodiment of the invention, the diluent comprises mineral oil.

[0037] In a specific embodiment of the present invention, the styrene block copolymer includes at least one of a styrene-isoprene-styrene (SIS) block copolymer, a styrene-butadiene-styrene (SBS) block copolymer, a styrene-ethylene / butylene-styrene (SEBS) block copolymer, and a styrene-ethylene / propylene-styrene (SEPS) block copolymer.

[0038] In a specific embodiment of the present invention, the antioxidant includes at least one of a hindered phenol antioxidant, a phosphite antioxidant, and a dipropyl thioate antioxidant. For example, the antioxidant 1010 and the antioxidant 168 may be compounded, but not limited thereto. The mass ratio of the antioxidant 1010 to the antioxidant 168 is 1:1.

[0039] The second aspect of the present invention provides a method for preparing the hot melt pressure-sensitive adhesive of the first aspect of the present invention, 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 a hydrogenated rosin resin, and mixing and stirring at 140-160°C to obtain a hot melt pressure-sensitive adhesive.

[0040] In a specific embodiment of the present invention, the mixture is stirred at 160-170° C. for 30-50 min and vacuumized.

[0041] In a specific embodiment of the present invention, the mixture is stirred under vacuum at 140-160° C. for 40-60 min.

[0042] In a specific embodiment of the present invention, the method further comprises: coating the hot melt pressure sensitive adhesive on the surface of the substrate. Further, the coating temperature is 150-170° C. and the coating weight is 10-25 gsm.

[0043] The third aspect of the present invention provides a label product, comprising 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 by the first aspect of the present invention.

[0044] In a specific embodiment of the present invention, the label product further comprises a release film layer; the release film layer is arranged on the surface of the hot-melt pressure-sensitive adhesive layer away from the label body. When laminating, the release film layer is removed and laminating is performed.

[0045] Example 1

[0046] This embodiment provides a hot melt pressure-sensitive adhesive, comprising the following components in parts by weight:

[0047] 21 parts of diluent, 21 parts of styrene block copolymer, 4 parts of ethylene-acrylic acid copolymer, 54 parts of hydrogenated rosin resin and 1 part of antioxidant.

[0048] 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: Exxon, USA), the hydrogenated rosin resin is hydrogenated rosin resin KHR75 (acid value is 160-180 mgKOH / g, manufacturer: Guangdong Kemao Forest Chemical Co., Ltd.), and the antioxidants are antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0049] The preparation method of the hot melt pressure sensitive adhesive of this embodiment comprises the following steps:

[0050] (1) Styrene block copolymer, antioxidant and diluent were mixed and stirred at 165°C for 40 minutes and then vacuumed.

[0051] (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 minutes.

[0052] (3) The material obtained in step (2) is coated on a PET substrate at a coating temperature of 160° C. and a coating weight of 20 gsm, and then rolled up for standby use.

[0053] Example 2

[0054] This embodiment refers to the hot melt pressure sensitive adhesive and preparation method thereof of embodiment 1, the only difference being that the amounts of the components in the hot melt pressure sensitive adhesive are different.

[0055] The hot melt pressure-sensitive adhesive of this embodiment includes the following components in parts by weight: 22 parts of diluent, 26 parts of styrene block copolymer, 4 parts of ethylene-acrylic acid copolymer, 48 parts of hydrogenated rosin resin and 1 part of antioxidant.

[0056] Example 3

[0057] This embodiment refers to the hot melt pressure sensitive adhesive and preparation method thereof of embodiment 1, the only difference being that the amounts of the components in the hot melt pressure sensitive adhesive are different.

[0058] The hot melt pressure-sensitive adhesive of this embodiment includes the following components in parts by weight: 22 parts of diluent, 27 parts of styrene block copolymer, 3 parts of ethylene-acrylic acid copolymer, 48 parts of hydrogenated rosin resin and 1 part of antioxidant.

[0059] Example 4

[0060] This embodiment refers to the hot melt pressure sensitive adhesive and preparation method thereof of embodiment 1, the only difference being that the amounts of the components in the hot melt pressure sensitive adhesive are different.

[0061] The hot melt pressure-sensitive adhesive of this embodiment includes the following components in parts by weight: 14 parts of diluent, 35 parts of styrene block copolymer, 4 parts of ethylene-acrylic acid copolymer, 47 parts of hydrogenated rosin resin and 1 part of antioxidant.

[0062] Example 5

[0063] This embodiment refers to the hot melt pressure sensitive adhesive and preparation method thereof of embodiment 1, the only difference being that the amounts of the components in the hot melt pressure sensitive adhesive are different.

[0064] The hot melt pressure-sensitive adhesive of this embodiment includes the following components in parts by weight: 24 parts of diluent, 35 parts of styrene block copolymer, 6 parts of ethylene-acrylic acid copolymer, 35 parts of hydrogenated rosin resin and 1 part of antioxidant.

[0065] Example 6

[0066] This embodiment refers to the hot melt pressure sensitive adhesive and preparation method thereof of Embodiment 2, the only difference being that the type of hydrogenated rosin resin is different.

[0067] The hydrogenated rosin resin in this embodiment is hydrogenated rosin resin H120F (acid value>210mg KOH / g and ≤265mgKOH / g, manufactured by Guangdong Kemao Forestry Chemical Co., Ltd.).

[0068] Example 7

[0069] This embodiment refers to the hot melt pressure sensitive adhesive and preparation method thereof of Embodiment 2, the only difference being that the type of ethylene-acrylic acid copolymer is different.

[0070] The ethylene-acrylic acid copolymer in this embodiment is ESCOR EAA5000 (acrylic acid content 6%, manufactured by Exxon, USA).

[0071] Example 8

[0072] This embodiment refers to the hot melt pressure sensitive adhesive and preparation method thereof of embodiment 2, the only difference being that the amounts of the components in the hot melt pressure sensitive adhesive are different.

[0073] The hot melt pressure-sensitive adhesive of this embodiment includes the following components by weight: 22 parts of diluent, 24 parts of styrene block copolymer, 6 parts of ethylene-acrylic acid copolymer, 48 parts of hydrogenated rosin resin and 1 part of antioxidant.

[0074] Example 9

[0075] This embodiment refers to the hot melt pressure sensitive adhesive and preparation method thereof of embodiment 2, the only difference being that the amounts of the components in the hot melt pressure sensitive adhesive are different.

[0076] The hot melt pressure-sensitive adhesive of this embodiment includes the following components in parts by weight: 22 parts of diluent, 27.5 parts of styrene block copolymer, 2.5 parts of ethylene-acrylic acid copolymer, 48 parts of hydrogenated rosin resin and 1 part of antioxidant.

[0077] Comparative Example 1

[0078] Comparative Example 1 refers to the hot melt pressure sensitive adhesive and preparation method thereof of Example 2, except that the type of hydrogenated rosin resin is different.

[0079] The hydrogenated rosin resin of Comparative Example 1 is hydrogenated rosin resin KA100W (acid value ≤ 30 mgKOH / g, manufactured by Guangdong Kemao Linchan Chemical Co., Ltd.).

[0080] Comparative Example 2

[0081] Comparative Example 2 refers to the hot melt pressure-sensitive adhesive and its preparation method of Example 2, except that: the amount of each component in the hot melt pressure-sensitive adhesive is different.

[0082] The hot melt pressure-sensitive adhesive of Comparative Example 2 includes the following components in parts by weight: 22 parts of diluent, 40 parts of styrene block copolymer, 4 parts of ethylene-acrylic acid copolymer, 34 parts of hydrogenated rosin resin and 1 part of antioxidant.

[0083] Comparative Example 3

[0084] Comparative Example 3 refers to the hot melt pressure sensitive adhesive and preparation method thereof of Example 2, except that the amounts of the components in the hot melt pressure sensitive adhesive are different.

[0085] The hot melt pressure-sensitive adhesive of Comparative Example 3 includes the following components in parts by weight: 22 parts of diluent, 30 parts of styrene block copolymer, 48 parts of hydrogenated rosin resin and 1 part of antioxidant.

[0086] Comparative Example 4

[0087] Comparative Example 4 refers to the hot melt pressure-sensitive adhesive and preparation method thereof of Example 2, except that an equal weight of non-hydrogenated rosin resin 278L (acid value ≤ 170 mgKOH / g, manufactured by Guangdong Kemao Linchan Chemical Co., Ltd.) is used to replace the hydrogenated rosin resin in Example 2.

[0088] Experimental example

[0089] In order to compare and illustrate the performance differences of the hot melt pressure-sensitive adhesives of different embodiments and comparative examples, the following tests were conducted. The test results are shown in Table 1.

[0090] Peel strength: The PET samples prepared in each embodiment and comparative example were attached to a steel plate, and the peel strength was tested according to GB / T 2792;

[0091] Peel strength after aging at 70°C for 3 days: Prepare the pasted samples as above, place them at 70°C for 3 days, and then test the peel strength of the steel plate according to GB / T 2792;

[0092] Loop initial adhesion: The PET samples prepared in each embodiment and comparative example were tested for loop initial adhesion against a steel plate according to GB / T 31125;

[0093] Alkaline washing effect of PET bottles: Prepare 5wt% NaOH aqueous solution and heat it to 80℃. Paste the PET sample on the PET bottle. Cut the bottle with the PET sample into squares of 1cm*1cm, put it into alkaline water and stir it. Observe whether it falls off within 10 minutes and record the time of falling off.

[0094] Alkaline water washing effect of glass bottles: Prepare a 5wt% NaOH aqueous solution and heat it to 80°C. Paste the PET sample on the glass bottle and soak it in alkaline water to observe whether it falls off within 5 minutes and record the time of falling off.

[0095] Die-cutting property: about 500 meters of PET large roll samples prepared in various embodiments and comparative examples were tested for die-cutting property in a label die-cutting and waste discharge device to observe whether the die-cutting was smooth;

[0096] At a die-cutting speed of 100m / min, there is no sticking, no flying marks, and waste discharge is smooth and continuous, and its die-cutting performance is excellent;

[0097] At a die-cutting speed of 100m / min, there are 1-2 times of adhesion or waste discharge breakage. The die-cutting speed needs to be reduced to achieve no adhesion, no flying marks, and smooth and continuous waste discharge. Its die-cutting performance is good;

[0098] At a die-cutting speed of 100 m / min, the number of adhesion or waste breakage is greater than 2 times, and its die-cutting property is poor.

[0099] Table 1 Test results of different hot melt pressure sensitive adhesives

[0100]

[0101] According to the test results of the embodiment and comparative example 1, the acid value of the hydrogenated rosin resin used in comparative example 1 is relatively low, and separation cannot be achieved in alkaline water. According to the test results of the embodiment and comparative example 2, the amount of hydrogenated rosin resin in comparative example 2 is small, and separation cannot be achieved in alkaline water. According to the test results of the embodiment and comparative example 3, ethylene-acrylic acid copolymer is not used in comparative example 3, and the peel strength of the corresponding hot melt pressure-sensitive adhesive is low, the die-cutting property is poor, and the separation speed in alkaline water is slow. According to the test results of the embodiment and comparative example 4, non-hydrogenated rosin resin is used in comparative example 4 to replace hydrogenated rosin resin, and the aging resistance of the corresponding hot melt pressure-sensitive adhesive is significantly deteriorated.

[0102] From the above test results, it can be seen that the hot-melt pressure-sensitive adhesive of the present invention has excellent adhesion (peel strength ≥15N / inch, initial adhesion ≥15N / inch), thermal stability and aging resistance, and good environmental protection. At the same time, it can quickly lose adhesion under alkaline water conditions to achieve separation between the label and the adhered object, which is helpful to realize the automated container recycling process.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. Hot melt pressure sensitive adhesive, characterized in that: It includes the following components by weight: 14-25 parts of diluent, 21-35 parts of styrene block copolymer, 2.5-6 parts of ethylene-acrylic acid copolymer, 47-55 parts of hydrogenated rosin resin and 0.2-2 parts of antioxidant; The acid value of the hydrogenated rosin resin is 150-210 mg KOH / g; The mass ratio of the ethylene-acrylic acid copolymer to the styrene block copolymer is 1:(5-10); In the ethylene-acrylic acid copolymer, the content of acrylic acid is 10wt% to 15wt%.

2. The hot melt pressure sensitive adhesive according to claim 1, characterized in that: The diluent includes mineral oil.

3. The hot melt pressure sensitive adhesive according to claim 1, characterized in that: The styrene block copolymer includes at least one of a styrene-isoprene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, a styrene-ethylene / butylene-styrene block copolymer, and a styrene-ethylene / propylene-styrene block copolymer.

4. The hot melt pressure sensitive adhesive according to claim 1, characterized in that: The antioxidant comprises at least one of a hindered phenol antioxidant, a phosphite antioxidant and a dipropyl thioate antioxidant.

5. The method for preparing the hot melt pressure sensitive adhesive according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: mixing and stirring styrene block copolymer, antioxidant and diluent at 160-170 DEG C, then adding ethylene-acrylic acid copolymer and hydrogenated rosin resin, mixing and stirring at 140-160 DEG C to obtain hot melt pressure sensitive adhesive.

6. A label product, characterized in that: It comprises a label body and a hot-melt pressure-sensitive adhesive layer arranged on the label body; the hot-melt pressure-sensitive adhesive layer is mainly made of the hot-melt pressure-sensitive adhesive according to any one of claims 1 to 4.

7. The label product according to claim 6, characterized in that: The label product further comprises a release film layer; the release film layer is arranged on a surface of the hot-melt pressure-sensitive adhesive layer away from the label body.

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