A hot melt adhesive for a non-peeling type sealing tape and its production process

Abstract

The present invention provides a hot melt adhesive for a non-peeling type sealing tape and its production process. The present invention belongs to the technical field of hot melt adhesives, and relates to a hot melt adhesive for a non-peeling type sealing tape and its production process. The hot melt adhesive comprises: 20 - 35 parts of a matrix resin, 10 - 25 parts of a styrene-based thermoplastic elastomer composition, 30 - 50 parts of a tackifying resin, 15 - 30 parts of a viscosity regulator, 0.5 - 1.5 parts of an anti-sticking agent, and 0.2 - 1.0 parts of an antioxidant. The beneficial effects of the present invention are as follows: compared with the prior art, firstly, when the hot melt adhesive of the present invention is coated into a tape, the amide will migrate to the surface of the adhesive layer and arrange into an approximate monolayer with a low surface energy, thereby achieving the anti-adhesion effect, that is, it can prevent the adhesive particles from sticking and caking, and can also improve the tape unwinding performance, without the need to attach an isolation material, achieving the effect of non-peeling use; secondly, the low-temperature resistance of the hot melt adhesive is improved, so that the product can still maintain good adhesion in a low-temperature environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of hot melt adhesives, and relates to a hot melt adhesive for a non-peeling type sealing tape and its production process. Background Art

[0002] Common medical protective clothing is usually a one-piece structure composed of a hat, a coat, and trousers, with high protection, sealing, safety, and hygiene, and has strict standards in production. Existing medical protective clothing needs to be made through cutting, sewing, adding elastic bands, and bonding and pressing rubber strips. The processes involved include flat sewing, overlock sewing, and pressing rubber. Among them, pressing rubber is a crucial step to achieve the high-sealing function of the protective clothing, and the quality of the adhesive used for the sealing rubber strip determines the effect of pressing rubber, which in turn affects the anti-bacterial, anti-dust, anti-liquid, and anti-gas effects of the protective clothing.

[0003] At present, some domestic protective clothing manufacturers use pressure-sensitive adhesives for coating to produce sealing tapes. After coating, it is necessary to attach a release film for anti-sticking before winding and cutting. During the rubber pressing operation, it is necessary to remove the release film while pressing, which has the problems of complex production process and low efficiency, and is not conducive to quickly responding to the sudden increase in market demand during the outbreak of the epidemic. At the same time, the bonding strength of the pressure-sensitive sealing tape after pressing is low, and the lap joint is easy to bounce up and lose the sealing function.

[0004] Some other manufacturers use hot melt adhesives prepared based on ethylene-vinyl acetate copolymer resin for coating production of sealing tapes, which have good adhesiveness to the protective clothing fabric at room temperature, but the tape is easy to fall off in a low-temperature environment. The Chinese invention patent with the application publication number CN112266735A and the application publication date of January 26, 2021, discloses an adhesive for a disposable non-woven protective clothing tape, which uses ethylene-vinyl acetate copolymer as the main resin and improves the adhesiveness of the hot melt adhesive and the ability to maintain high adhesiveness in a high-humidity environment by adding glass fibers. However, the system with ethylene-vinyl acetate copolymer as the main resin is difficult to meet the severe cold environment in the north in winter, and the tape is easy to fall off. Summary of the Invention

[0005] In order to solve the above problems, the primary object of the present invention is to provide a hot melt adhesive for a non-peeling type sealing tape and its production process. When coated into a tape, the amide will migrate to the surface of the adhesive layer and arrange into an approximate monolayer with low surface energy, so as to achieve the anti-adhesion effect, that is, it can prevent the adhesive particles from sticking and caking, and can also improve the tape unwinding performance, without the need to attach an isolation material, achieving the effect of non-peeling and use.

[0006] Another object of the present invention is to provide a hot melt adhesive for a non-peeling type sealing tape and its production process, which improves the low-temperature resistance of the hot melt adhesive, so that the product can still maintain good adhesion in a low-temperature environment.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] The present invention provides a hot melt adhesive for a non-peeling type sealing tape. By mass fraction, the hot melt adhesive comprises:

[0009] Matrix resin: 20 - 35 parts,

[0010] Styrene-based thermoplastic elastomer composition: 10 - 25 parts,

[0011] Tackifying resin: 30 - 50 parts,

[0012] Viscosity regulator: 15 - 30 parts,

[0013] Anti-sticking agent: 0.5 - 1.5 parts,

[0014] Antioxidant: 0.2 - 1.0 part.

[0015] Furthermore, the matrix resin is any one or a combination of vinyl thermoplastic polyolefin plastomer, vinyl thermoplastic polyolefin elastomer, and propylene-based thermoplastic polyolefin elastomer.

[0016] Preferably, the vinyl thermoplastic polyolefin plastomer and vinyl thermoplastic polyolefin elastomer are ethylene-octene random copolymers, wherein the mass percentage content of octene in the elastomer is 9.0% - 20%, and the melt index is 18 - 35 g / 10 min (2.16 kg, 190 °C); the mass percentage content of octene in the plastomer is 10% - 15%, and the melt viscosity at 177 °C is 5000 - 20000 cps. In the present invention, it can be understood that by introducing octene copolymer monomers into the polyethylene chain segment, a large number of amorphous regions are present in the copolymer, so good adhesiveness can be provided. This adhesiveness is determined by the structure of the raw materials themselves, so it will not change with environmental factors such as temperature and humidity and can be maintained for a long time; at the same time, the introduction of flexible octene segments brings a lower glass transition temperature to the copolymer, reaching -45 °C to -57 °C, thus having excellent low-temperature flexibility and low-temperature adhesiveness.

[0017] Preferably, the propylene-based thermoplastic polyolefin elastomer is a random copolymer obtained by copolymerizing propylene as the base material with a small amount of ethylene monomer, and the mass percentage content of ethylene is 12% - 16%, and the melt index is 1.0 - 25 g / 10 min (2.16 kg, 190 °C). Similar to the ethylene-octene random copolymer, by introducing ethylene monomers for copolymerization, the crystalline structure of polypropylene is destroyed, so a large number of amorphous regions are present in the copolymer, endowing the copolymer with good hot adhesiveness.

[0018] Furthermore, the styrenic thermoplastic elastomer composition includes one or more compositions selected from SIS-SBS, SIS-SEBS, SEPS-SBS, and SIS-SEPS. The SIS-SBS is a mixture of SIS and SBS, the SIS-SEBS is a mixture of SIS and SEBS, the SEPS-SBS is a mixture of SEPS and SBS, and the SIS-SEPS is a mixture of SIS and SEPS. SIS: styrene-isoprene block copolymer; SBS: styrene-butadiene block copolymer; SEBS: hydrogenated product of styrene-butadiene block copolymer; SEPS: hydrogenated product of styrene-isoprene block copolymer.

[0019] Preferably, the composition is SIS-SEBS, and the mass ratio of SIS to SEBS is 4:1. Among them, the mass percentage content of styrene in SIS is 15% - 25%, and the mass percentage content of the isoprene block is 75% - 85%; the mass percentage content of styrene in SEBS is 20% - 40%. In order to improve the fluidity of the hot melt adhesive and enhance the coating performance, the melt index of the SIS is 5 - 25 g / 10 min (200 °C, 5 kg). In the present invention, the styrenic thermoplastic elastomer has two independent phase regions, namely a plastic phase and a rubber phase. The plastic phase acts as a hard segment and plays a role of physical crosslinking in the entire molecular structure, while the rubber phase acts as a soft segment, endowing the material with low-temperature flexibility, adhesiveness, and high elasticity. Therefore, the presence of the styrenic thermoplastic elastomer improves the adhesiveness and bonding strength of the hot melt adhesive on the one hand, and enhances the low-temperature resistance of the hot melt adhesive on the other hand, enabling the product to maintain good adhesion in a low-temperature environment. Additionally, SEBS is a hydrogenated styrenic thermoplastic elastomer, and its molecular structure is relatively close to that of polyolefins after hydrogenation. Thus, it has very good compatibility with polyolefins. By adding SEBS, the compatibility between the polyolefin-based matrix resin and the styrenic elastomer can be significantly improved, ensuring the stable performance of the hot melt adhesive and maintaining a long-term effective bonding effect.

[0020] Furthermore, the tackifying resin is a composition of one or more selected from pentaerythritol ester of rosin, glycerol ester of rosin, rosin, C5 petroleum resin, hydrogenated C5 petroleum resin, and terpene resin, and the ring and ball softening point of the tackifying resin is 85 - 100 °C. It can be understood that the tackifying resin, as a low-molecular-weight amorphous thermoplastic polymer, can improve the wettability of the hot melt adhesive, enabling it to fully adhere to the adherend, thereby increasing the adhesiveness of the hot melt adhesive, enhancing the bonding strength, improving the impact strength, peel strength, etc. of the adhesive, extending the bonding service life, and reducing the viscosity for convenient coating operation.

[0021] Preferably, hydrogenated C5 resin and rosin pentaerythritol ester are compounded as tackifiers, and the polar carboxyl, ester and hydroxyl groups in rosin pentaerythritol ester are used to increase the interaction between the colloid molecules and the protective clothing fabric molecules, thereby improving the adhesion of the hot melt adhesive to fabrics of different materials. Hydrogenated C5 resin is an aliphatic polymer with a flexible molecular chain, which has good compatibility with the matrix resin and styrene elastomer, and can improve the thermal adhesion and low temperature resistance of the hot melt adhesive.

[0022] Furthermore, the viscosity modifier is a combination of one or more of paraffin wax, microcrystalline wax, Fischer-Tropsch wax and polyethylene wax. Paraffin wax, microcrystalline wax, Fischer-Tropsch wax and polyethylene wax are all low molecular polymers, which can reduce the melt viscosity of the hot melt adhesive, improve fluidity and prevent the adhesive from self-adhesion. At the same time, wax acts as a compatibilizer for the elastomer matrix and the tackifying resin, improves the compatibility of the matrix resin-tackifying resin, causes the matrix molecules and tackifying resin molecules in the original dispersed tackifying resin phase to migrate to the matrix phase, increases the volume percentage of the viscoelastic matrix phase in the entire adhesive, thereby improving the viscoelasticity of the hot melt adhesive, improving the peel strength and improving the bonding effect.

[0023] Further, the anti-adhesive is a combination of one or more of erucamide, oleamide and stearamide. In the present invention, since the compatibility between erucamide and oleamide and polymer is very poor, after the amide anti-adhesive is added to the hot melt adhesive, when it is coated into an adhesive tape, the amide will migrate to the surface of the adhesive layer and arrange into a low surface energy approximate monomolecular layer, thereby achieving an anti-adhesion effect. On the one hand, it can prevent the adhesive particles from sticking together, and on the other hand, the unwinding performance of the adhesive tape with hot melt adhesive prepared later will be significantly improved, and finally the purpose of using without covering the isolation material and avoiding removal is achieved. Specifically: due to the limited chemical compatibility of amide in hot melt adhesives with polyolefin as the matrix resin, during high-temperature processing, amide dissolves in the molten amorphous area. When the hot melt adhesive is applied, the temperature drops and these amorphous areas begin to crystallize. Since the molecular free volume of the crystalline area is smaller than that of the amorphous area, the amide migrates (extrudes) out of the solidified polymer matrix. The migrated amide forms an anti-adhesion layer due to the inherent molecular mutual attraction and relative polarity, filling the defects and depressions on the surface of the adhesive layer, playing a partial barrier role between the adhesive layer and the back of the tape, reducing the initial adhesion between the adhesive layer and the tape at room temperature, and improving the unwinding performance.

[0024] In addition, when the tape is used for hot melt lamination, it is usually heated with hot air at about 300 °C and a pressure of about 0.5 Mpa is applied. At this time, the crystalline phase of the hot melt adhesive remelts into the amorphous phase. Under the action of the pressure and the concentration gradient of the anti-sticking agent, the anti-sticking agent migrates into the hot melt adhesive. After cooling, since the hot melt adhesive molecules are in full contact with the back surface of the tape and the bonding surface of the fabric, the surface defects and recesses are filled, preventing the anti-sticking agent molecules from diffusing to the bonding interface and being locked in the hot melt adhesive layer, without affecting the bonding between the adhesive layer and the fabric. In other words, after the hot melt adhesive added with the anti-sticking agent is coated to form a tape, in the state where the adhesive layer is not melted, the anti-sticking agent molecules can form an anti-sticking layer on the surface of the adhesive layer to prevent the adhesive layer from adhering to the back surface of the tape. When the tape is used, there is no need to remove the anti-sticking agent layer, and it can be directly laminated at high temperature. After firm bonding, whether it is placed at room temperature or low temperature (avoid high temperature placement) environmental temperature, the formed bonding strength will no longer be affected by the anti-sticking agent.

[0025] Further, the antioxidant is a composition of one or more of tris[2,4-di-tert-butylphenyl]phosphite, n-octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, dilauryl thiodipropionate, 2,6-di-tert-butyl-p-cresol, and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. In the present invention, the thermal oxidation process of organic compounds is a series of free radical chain reactions. Under the action of heat, light or oxygen, the chemical bonds of organic molecules are broken, generating active free radicals and hydroperoxides. The hydroperoxides undergo decomposition reactions to also generate hydrocarbonoxy free radicals and hydroxyl free radicals. These free radicals can initiate a series of free radical chain reactions, resulting in fundamental changes in the structure and properties of organic compounds. The role of the antioxidant is to eliminate the newly generated free radicals or promote the decomposition of hydroperoxides to prevent the progress of the chain reaction.

[0026] Further, the present invention provides a production process for a hot melt adhesive for a non-peeling type sealing tape, comprising the following steps:

[0027] S1: Put the viscosity regulator, antioxidant and anti-sticking agent into a reaction kettle, carry out low-speed stirring operation, and heat to 140 - 150 °C to completely melt and mix the above materials to obtain a first mixed phase;

[0028] S2. Add all the matrix resin compositions to the first mixed phase, raise the temperature to 160 - 170 °C and carry out high-speed stirring operation to completely melt and mix the above materials to obtain a second mixed phase;

[0029] S3. Add the styrene-based thermoplastic elastomer composition to the second mixed phase, evacuate, control the vacuum degree of the reaction kettle to be 0.05 Mpa - 0.1 Mpa, and stir at full speed to completely melt the above materials until there is no particle feeling to obtain a third mixed phase;

[0030] S4. Add all the tackifying resins to the third mixed phase, lower the temperature to 140 - 150 °C, and evacuate to maintain a vacuum degree of 0.08 Mpa - 0.1 Mpa, and stir at high speed for 20 - 30 min to form a homogeneous mixture;

[0031] S5. Discharge, filter, extrude and pelletize, and package after cooling to obtain the finished product.

[0032] The beneficial effects of the present invention are as follows: Compared with the prior art,

[0033] First of all, when the hot melt adhesive of the present invention is coated into a tape, the amide will migrate to the surface of the adhesive layer and arrange into an approximate monolayer with low surface energy, so as to achieve the anti - adhesion effect, that is, it can prevent the adhesive particles from sticking and caking, and can also improve the tape unwinding performance. There is no need to attach a release material, achieving the effect of being used without peeling off;

[0034] Secondly, the low - temperature resistance of the hot melt adhesive is improved, so that the product can still maintain good adhesion in a low - temperature environment. Specific embodiments

[0035] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0036] To achieve the above - mentioned purpose, the technical solution of the present invention is as follows:

[0037] Example 1: 25 parts of matrix resin, 15 parts of styrene - based thermoplastic elastomer composition, 40 parts of tackifying resin, 20 parts of viscosity regulator, 1.0 part of anti - sticking agent, 0.6 part of antioxidant.

[0038] Examples 2 - 6: Only the material contents are different, and the others are the same as in Example 1.

[0039] Comparative Examples 1 - 5: The selected materials or contents are not within the defined range.

[0040] Examples 1 - 6 are prepared according to the following steps:

[0041] 1. Put all the viscosity regulator, antioxidant and anti - sticking agent into the reaction kettle, carry out low - speed stirring operation, and heat to 140 - 150 °C to completely melt and mix the above materials to obtain the first mixed phase;

[0042] 2. Add all the matrix resin compositions to the first mixed phase, raise the temperature to 160 - 170 °C and carry out high - speed stirring operation to completely melt and mix the above materials to obtain the second mixed phase;

[0043] 3. Add a styrene-based thermoplastic elastomer composition to the second mixed phase, evacuate the air, control the vacuum degree of the reaction kettle to be 0.05 Mpa to 0.1 Mpa, and stir at full speed to completely melt the above materials until there is no granular feeling, obtaining a third mixed phase;

[0044] 4. Add all the tackifying resins to the third mixed phase, lower the temperature to 140 - 150 °C, and evacuate the air, maintaining the vacuum degree at 0.08 Mpa to 0.1 Mpa, and stir at high speed for 20 - 30 min to form a homogeneous mixture;

[0045] 5. Discharge the material, filter it, extrude and pelletize it, and package it after cooling to obtain the finished product.

[0046] Table 1: Material Components of Examples 1 - 6 and Comparative Examples 1 - 5

[0047]

[0048] Table 2: Performance Test Results of Each Example and Comparative Example

[0049]

[0050] Remarks: 1. Breaking of the material, deformation, and peeling off represent three different peeling effects. Breaking of the material indicates that the tape and the fabric are firmly bonded, and the peeling strength is greater than the cohesive strength of the fabric; deformation indicates that the hot melt adhesive has a relatively large adhesive force to the fabric, but the peeling strength or the cohesive strength of the hot melt adhesive is less than the cohesive strength of the fabric; peeling off indicates poor bonding effect and small peeling strength. 2. When the unwinding force is less than 1.5 N / 8 mm, it is considered that the tape can be unwound smoothly; when the unwinding force is greater than 1.5 N / 8 mm and less than 10 N / 8 mm, it is considered that the tape can be unwound but with difficulty; when the unwinding force is greater than 10 N / 8 mm, the PEVA tape is deformed or broken, and it is considered that the tape cannot be unwound.

[0051] Examples 1 - 6 are within the limited types and proportions of materials, and only the material contents are different. They have good bonding effects on medical protective fabrics, can be unwound smoothly, do not require additional release paper / membrane and other isolation materials, and can be directly used during pressure-sensitive adhesive application, eliminating the step of removing the isolation materials.

[0052] Compared with Example 1, Example 2 uses a single POP as the matrix resin, and the others are the same. Because the molecular weight of POP is less than that of POE and the cohesive strength is relatively low, the strength of the obtained hot melt adhesive at room temperature is slightly poor. Therefore, the bonding effect of Example 2 at room temperature is inferior to that of Example 1, while the bonding effect at low temperature is not affected.

[0053] Compared with Example 1, Example 3 uses a single SIS as the styrene elastomer, and the other parts are the same. Because SIS has poor compatibility with polyolefin polymers, the hot melt adhesive prepared without adding SEBS has poor compatibility, so the adhesion to the medical protective clothing fabric at room temperature and low temperature of -20°C is not as good as that of Example 1, and the unwinding force is slightly improved.

[0054] Compared with Example 1, Example 4 has 10 more tackifying resins. On the one hand, the increase in the tackifying resin content will increase the surface viscosity of the hot melt adhesive and improve the unwinding force; on the other hand, compared with other components, the tackifying resin has a high glass transition temperature, and the increase in its content will increase the glass transition temperature of the hot melt adhesive, thereby deteriorating the low-temperature adhesion of the hot melt.

[0055] Compared with Example 1, Example 5 has 5 more viscosity modifiers, and the other contents are the same. It can be understood that although wax viscosity modifiers can reduce the surface viscosity of hot melt adhesives and play an anti-sticking role, as the wax molecules migrate to the surface of the adhesive layer, the adhesion of the hot melt adhesive to the fabric of the medical protective clothing decreases, thereby affecting the bonding strength of the tape at low temperatures.

[0056] Compared with Example 1, Example 6 uses a different SIS brand, but the others are the same. The SIS selected in Example 1 has a styrene content of 15% and a diblock content of 38%; the SIS selected in Example 6 has a styrene content of 15% and a diblock content of 19%. It can be understood that when the styrene content is the same, a higher diblock content can improve the initial adhesion and adhesion of the hot melt adhesive. Therefore, Example 1 has a better bonding effect on medical protective clothing fabrics than Example 6 at different ambient temperatures, while the unwinding force is the opposite.

[0057] Compared with Example 1, the material types or contents of Comparative Examples 1-5 exceed the specified range. It can be seen from the data of Comparative Example 1 that when no anti-adhesive agent is added, the unwinding force of the hot melt adhesive is significantly increased, and it is difficult to unwind when not treated, and it cannot even be unwound after being treated at 55°C for 8 hours. Comparative Example 2 shows that when EVA is selected as the base resin, the bonding effect at low temperature is poor and cannot meet the requirements. However, thermoplastic polyolefin elastomers and plastomers have a glass transition temperature as low as -57°C, and have excellent low-temperature resistance when used as the base resin of hot melt adhesive. Comparative Examples 3 and 4 show that too little tackifying resin will result in poor bonding effect, too much will result in poor low-temperature resistance, and the tape prepared will be difficult to unwind. Example 5 shows that a low content of styrene elasticity will lead to poor bonding effect of hot melt adhesive. This is because in the entire formulation system, styrene elastomer provides enhanced adhesion on the one hand, improves low-temperature flexibility on the other hand, and at the same time gives the hot melt adhesive sufficient cohesive strength, which is a key link in balancing the adhesion and low-temperature resistance of hot melt adhesive.

[0058] The above embodiments are only used to illustrate the present invention, and the protection scope of the present invention is not limited to the above embodiments. Those of ordinary skill in the art can achieve the purpose of the present invention based on the content disclosed above and the ranges of various parameters.

Claims

1. A hot melt adhesive for a non-removable sealing tape, characterized in that, by mass parts, the hot melt adhesive comprises: Matrix resin: 20 - 35 parts, Styrene-based thermoplastic elastomer composition: 10 - 25 parts, Tackifying resin: 30 - 50 parts, Viscosity regulator: 15 - 30 parts, Anti-sticking agent: 0.5 - 1.5 parts, Antioxidant: 0.2 - 1.0 part; The matrix resin is any one or a combination of vinyl thermoplastic polyolefin plastomer, vinyl thermoplastic polyolefin elastomer, and propylene-based thermoplastic polyolefin elastomer; The anti-sticking agent is a composition of one or more of erucic acid amide, oleic acid amide, and stearic acid amide.

2. The hot melt adhesive for a non-removable sealing tape according to claim 1, characterized in that, The vinyl thermoplastic polyolefin plastomer and vinyl thermoplastic polyolefin elastomer are ethylene-octene random copolymers, and the mass percentage content of octene in the ethylene-octene random copolymer is 9.0% - 20%. Under the conditions of a load of 2.16 kg and a temperature of 190 °C, the melt index is 18 - 35 g / 10 min; the mass percentage content of octene in the plastomer is 10% - 15%, and the melt viscosity at 177 °C is 5000 - 20000 cps.

3. The hot melt adhesive for a non-removable sealing tape according to claim 1, characterized in that, The propylene-based thermoplastic polyolefin elastomer is a random copolymer obtained by copolymerizing propylene as the base material and introducing a small amount of ethylene monomer, and the mass percentage content of ethylene is 12% - 16%. Under the conditions of a load of 2.16 kg and a temperature of 190 °C, the melt index is 1.0 - 25 g / 10 min.

4. The hot melt adhesive for a non-removable sealing tape according to claim 1, characterized in that, The styrene-based thermoplastic elastomer composition includes a composition of one or more of SIS-SBS, SIS-SEBS, SEPS-SBS, and SIS-SEPS.

5. The hot melt adhesive for a non-removable sealing tape according to claim 1, characterized in that, The tackifying resin is a composition of one or more of pentaerythritol ester of rosin, glycerol ester of rosin, rosin, C5 petroleum resin, hydrogenated C5 petroleum resin, and terpene resin.

6. The hot melt adhesive for a non-removable sealing tape according to claim 1, characterized in that, The viscosity regulator is a composition of one or more of paraffin wax, microcrystalline wax, Fischer-Tropsch wax, and polyethylene wax.

7. The hot melt adhesive for a non-removable sealing tape according to claim 1, characterized in that, The antioxidant is a composition of one or more of tris[2,4-di-tert-butylphenyl] phosphite, n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, dilauryl thiodipropionate, 2,6-di-tert-butyl-p-cresol, and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate].

8. The production process of the hot melt adhesive for a non-removable sealing tape according to any one of claims 1 - 7, characterized in that, comprises the following steps: S1: Put the viscosity regulator, antioxidant and anti-sticking agent into the reaction kettle, carry out low-speed stirring operation, and heat to 140 - 150 °C to completely melt and mix the above materials to obtain the first mixed phase; S2. Add all the matrix resin compositions to the first mixed phase, raise the temperature to 160 - 170 °C and carry out high-speed stirring operation to completely melt and mix the above materials to obtain the second mixed phase; S3. Add the styrene-based thermoplastic elastomer composition to the second mixed phase, evacuate the air, control the vacuum degree of the reaction kettle to be 0.05 Mpa - 0.1 Mpa, and stir at full speed to completely melt the above materials until there is no particle feeling to obtain the third mixed phase; S4. Add all the tackifying resins to the third mixed phase, lower the temperature to 140 - 150 °C, and evacuate the air, keep the vacuum degree at 0.08 Mpa - 0.1 Mpa, and stir at high speed for 20 - 30 min to form a homogeneous mixture; S5. Discharge the material, filter, extrude and pelletize, and package after cooling to obtain the finished product.

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