Polyolefin hot melt adhesive and application thereof

Abstract

The invention provides a polyolefin hot melt adhesive. The polyolefin hot melt adhesive is prepared from a composition comprising polyolefin resin, non-modified wax, amide wax, tackifying resin, isocyanate, an antioxidant and optional oil. The polyolefin hot melt adhesive has the characteristics of high cohesion and high adhesive strength, is suitable for adhesion of materials coated with gloss oil and the like on the surface, and is particularly suitable for lap joint adhesion of oil-resistant filter stick forming paper in the tobacco industry.

Description

Technical Field

[0001] The invention belongs to the field of polymer material synthesis, and in particular relates to a polyolefin hot melt adhesive for filter rod joints and application thereof. Background Art

[0002] Piece of paper is a general term for acetate fiber tow packaging materials in the tobacco industry. In the past few years, the development of piece of paper has evolved from ordinary piece of paper to high-transparency piece of paper. With the development of popping bead type cigarettes, new piece of paper materials such as PET piece of paper and oil-resistant piece of paper have appeared in recent years, which has attracted great attention from tobacco companies.

[0003] Oil-resistant shaping paper is a special shaping paper with a smooth surface formed by adding an oil-immersing process to the production process of ordinary shaping paper, and then undergoing procedures such as extrusion, high-temperature curing, and shearing. The biggest advantage of oil-resistant shaping paper is that the permeability of oil and / or water to oil-resistant shaping paper is extremely low. When used in popping bead-type cigarettes, it can effectively prevent the penetration of flavor liquid into the shaping paper after the popping bead breaks (after the popping bead breaks, the flavor liquid penetrates through the ordinary shaping paper and easily flows out of the cigarette, and even sticks to the hands). But the disadvantages are also obvious. The bonding of oil-resistant shaping paper is relatively difficult. Ordinary thermoplastic EVA or polyolefin hot melt adhesives are difficult to bond effectively. At the same time, the stress caused by the deformation of the oil-resistant shaping paper, as well as the soaking and dissolution of triacetin, seriously affect its bonding and storage.

[0004] The Chinese patent application with publication number CN113322034A proposes to modify the hot melt adhesive for filter rods with low surface energy materials such as "alkyl siloxane and / or fluoroalkyl alkoxy silane" to achieve the purpose of triacetin resistance, thereby increasing the storage period of the filter rods. However, the premise of its application is that it is used in fields with low requirements for adhesion, such as ordinary plugging paper or high-transparency plugging paper, and is not suitable for PET plugging paper or oil-resistant plugging paper.

[0005] The Chinese patent application with publication number CN117363285A proposes to use a certain amount of phenolic hydroxyl-containing tackifying resin in hot melt adhesive, so that the phenolic hydroxyl reacts with isocyanate to form a micro PUR structure, and utilizes the principle that the reaction is reversible at 150-170°C to form a certain chemical reaction when the adhesive contacts the substrate, thereby improving the bonding strength. At the same time, since the isocyanate in the isocyanate is in a closed state, the viscosity of the hot melt adhesive does not change much during transportation, storage, and use, which provides a basis for the continuous and stable application of the hot melt adhesive. However, it can only achieve a high bonding effect in the initial stage of bonding. With the increase of storage time, the stress of the oil-resistant forming paper, the immersion and dissolution of triacetin, and the immersion of the plasticizer (used in the oil-resistant forming paper) make the colloid soft and the cohesive force decrease, which eventually leads to a decrease in bonding force, and even a small amount of displacement of a small amount of filter rods when they are overlapped, and the problem of bursting may occur in the later stage of storage. Summary of the invention

[0006] In order to enhance the cohesion of hot melt adhesive, increase resistance to plasticizers, and thereby improve the bonding ability to oil-resistant forming paper, the present invention provides a polyolefin hot melt adhesive with high cohesion and high adhesion, which is suitable for bonding materials coated with varnish and the like on the surface, especially for overlapping bonding of oil-resistant filter rod forming paper in the tobacco industry.

[0007] According to a first aspect of the present invention, there is provided a composition for preparing a polyolefin hot melt adhesive, the composition comprising a polyolefin resin, a non-modified wax, an amide wax, a tackifying resin, an isocyanate, an antioxidant and optionally an oil.

[0008] In some embodiments, the amide wax includes a compound having a structure shown in formula (I);

[0009]

[0010] Wherein, R1 is selected from a C12-C30 straight chain alkyl group;

[0011] R2 is selected from C1-C10 straight chain alkylene groups.

[0012] In some specific embodiments, in formula (I), R1 is selected from a straight chain alkyl group of C12, C14, C16, C18, C20, C22, C24, C26, C28 or C30; R2 is selected from a straight chain alkylene group of C1, C2, C3, C4, C5, C6, C7, C8, C9 or C10.

[0013] In some embodiments, the amide wax is obtained by a dehydration reaction of a C1-C1 difunctional primary amine and a C12-C30 monofunctional linear acid.

[0014] In some embodiments, the melting point of the amide wax is higher than 80° C., preferably 80-160° C., more preferably 120-150° C. In some specific embodiments, the melting point of the amide wax is 80° C., 100° C., 120° C., 140° C., 160° C. or any value therebetween.

[0015] In some embodiments, the non-modified wax is selected from one or more of Fischer-Tropsch wax, microcrystalline wax, polyethylene wax or paraffin wax.

[0016] In some embodiments, the mass ratio of the amide wax to the non-modified wax is 1:(0.5-10), preferably 1:(1-10). In some specific embodiments, the mass ratio of the amide wax to the non-modified wax is 1:0.5, 1:0.8, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:8, 1:10 or any value therebetween.

[0017] In some embodiments, the polyolefin resin includes one or more of polyethylene, polypropylene, binary copolymer resin of ethylene and propylene, binary copolymer resin of ethylene and 1-octene, binary copolymer resin of ethylene and butene, or binary copolymer resin of ethylene and hexene.

[0018] In some embodiments, the polyolefin resin is selected from POE elastomer resins.

[0019] In some embodiments, the tackifying resin is selected from one or both of terephthalic phenol resin and phenolic resin.

[0020] In some embodiments, the phenolic hydroxyl content of the tackifying resin is 20-300 mgKOH / g (HG / T2709), preferably 30-100 mgKOH / g.

[0021] In some embodiments, the phenol content of the tackifying resin is no greater than 20 mg / kg.

[0022] In some embodiments, the isocyanate is one or more selected from diphenylmethane diisocyanate or its phenolic blocked derivatives, a prepolymer formed by the reaction of diphenylmethane diisocyanate and a polyol or its phenolic blocked derivatives.

[0023] In some embodiments, the phenolic blocked derivative is a product obtained by a complete or partial addition reaction of a monofunctional phenolic blocking agent with diphenylmethane diisocyanate, wherein the monofunctional phenolic blocking agent includes one or more of methylphenol, methoxyphenol or bromophenol.

[0024] In some embodiments, the antioxidant is one or more selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 2,6-di-tert-butyl-p-cresol.

[0025] In some embodiments, the oil includes one or more of white oil, polyisobutylene, or paraffin oil.

[0026] In some embodiments, the molar ratio of the number of moles of isocyanic acid in the isocyanate to the number of moles of phenolic hydroxyl groups in the tackifying resin is 1:(0.5-1.5), preferably 1:(0.8-1.2), and more preferably 1:(0.98-1.05).

[0027] In some embodiments, the polyolefin hot melt adhesive comprises the following components by weight:

[0028]

[0029] In some embodiments, the polyolefin hot melt adhesive comprises the following components by weight:

[0030]

[0031] In some specific embodiments, the composition includes the following weight percentages of heavy components: polyolefin resin 10-50%, such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, preferably 15-40%; non-modified wax 5-30%, such as 5%, 10%, 15%, 20%, 25%, 30%, preferably 10-20%; amide wax 3-15%, such as 3%, 5%, 7%, 9%, 12%, 15%, preferably 5-12%; oil 0-15%, such as 2%, 3%, 4%, 5%, 6% %, 7%, 8%, 9%, 10%, 12%, 15%, preferably 3-10%; tackifying resin 20-60%, for example 28%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, preferably 35-55%; isocyanate 2-15%, for example 2%, 3%, 5%, 6%, 8%, 10%, 12%, 15%, preferably 5-12%; antioxidant 0.1-1%, for example 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, preferably 0.1-0.3%.

[0032] According to another aspect of the present invention, a polyolefin hot melt adhesive is provided. The polyolefin hot melt adhesive is prepared from the composition of the invention.

[0033] In some embodiments, when the polyolefin hot melt adhesive of the present invention is stored for 6 months, the filter rod is rotated 90° in the opposite direction for multiple times until it is broken, and the joint does not come apart.

[0034] According to another aspect of the present invention, there is provided a method for preparing a polyolefin hot melt adhesive, the method comprising the following steps:

[0035] (1) mixing a polyolefin resin, a non-modified wax, an amide wax, a tackifying resin, an antioxidant and an optional oil to obtain a mixture;

[0036] (2) reacting the mixture with isocyanate to obtain the polyolefin hot melt adhesive.

[0037] In some embodiments, in step (1), the mixing temperature is 150-170°C.

[0038] In some embodiments, in step (1), the vacuum degree of the mixing is not less than -0.08 MPa.

[0039] In some embodiments, in step (1), the stirring speed of the mixing is not less than 100 r / min.

[0040] In some embodiments, the water content of the mixture is less than 200 ppm, the vacuum is released and the temperature is lowered to 5-10° C. above the softening point, and isocyanate is added to carry out the reaction.

[0041] In some embodiments, in step (2), the reaction time is 10-60 min.

[0042] In some embodiments, in step (2), the reaction comprises reacting the mixture with isocyanate for 5-40 minutes and then reacting under vacuum conditions for 5-20 minutes.

[0043] According to another aspect of the present invention, there is provided the use of the polyolefin hot melt adhesive of the present invention or the polyolefin hot melt adhesive prepared by the preparation method in overlap bonding, especially in overlap bonding of oil-resistant molded paper filter rods.

[0044] The polyolefin hot melt adhesive of the invention is suitable for bonding materials coated with varnish and the like on the surface, especially for bonding the overlaps of oil-resistant molded paper filter rods in the tobacco industry.

[0045] According to another aspect of the present invention, a filter rod is provided, wherein the overlapped ends of the filter rod are bonded by the polyolefin hot melt adhesive of the present invention or the polyolefin hot melt adhesive prepared by the preparation method.

[0046] In some embodiments, the filter plug comprises an oil resistant plug paper filter plug.

[0047] In some embodiments, the filter plug comprises an oil-resistant plug paper filter plug used in tobacco production.

[0048] In order to solve the problem that the bonding strength of the hot melt adhesive is greatly reduced due to the infiltration of plasticizers in the late storage period during the application process, the present invention adds amide wax to the hot melt adhesive, and utilizes the large number of hydrogen atoms contained in the amide wax molecules to form a large number of hydrogen bonds with the benzene rings inside the system to increase the cohesive strength of the hot melt adhesive, thereby increasing the bonding force of the hot melt adhesive in the late storage period. The present invention also unexpectedly found that the addition of amide wax not only increases the cohesive strength of the hot melt adhesive layer, but also increases the bonding strength with the surface of the oil-resistant forming paper. DETAILED DESCRIPTION

[0049] The present invention is improved on the basis of patent publication number CN117363285A (the invention name is a hot melt adhesive for overlapping of oil-resistant filter rod molding paper and its preparation method), with the main goal of enhancing the cohesion of the hot melt adhesive and increasing the resistance to plasticizers, which is ultimately reflected in improving the bonding ability to oil-resistant molding paper.

[0050] To this end, the polyolefin hot melt adhesive of the present invention is prepared from a combination of polyolefin resin, non-modified wax, amide wax, tackifying resin, isocyanate, antioxidant and optional oil as raw materials.

[0051] The present invention improves the cohesive strength of the hot melt adhesive by adding amide wax. Amide wax is prepared by polymerization and dehydration reaction of organic acid and organic amine, and is generally used as an anti-precipitation agent, dispersant, brightener, lubricant, antistatic agent, demolding agent, etc. Different from general waxes which are alkanes, amide wax molecules contain amide bonds, which are its core functional groups, and have the following characteristics:

[0052] (1) The amide bond contains a secondary amine bond, and the hydrogen atom in the secondary amine bond is affected by the carbonyl group, which reduces its activity. At high temperature (160°C), the reaction with isocyanate is difficult and can be ignored.

[0053] (2) When the hydrogen atoms in the amide bond change from high temperature to low temperature, they will reform hydrogen bonds, which is reflected in the rapid increase of the viscosity of the system, and ultimately increase the cohesive strength of the hot melt adhesive.

[0054] (3) Amide waxes generally have a relatively high melting point, especially polyamide waxes. Considering the final use temperature of the present invention, the melting point is preferably not higher than 160°C.

[0055] In the present invention, the addition of amide wax significantly improves the cohesive strength of the hot melt adhesive, and the selected raw materials and preparation method are also special.

[0056] First, with the addition of amide wax, the presence of a large amount of hydrogen bonds significantly increases the cohesive strength of hot melt adhesives of different systems (polymers). However, the adhesion of polyethylene vinyl acetate (EVA) system hot melt adhesive has not increased significantly, and even decreased somewhat. The adhesion of ethylene, propylene and butene terpolymer resins remains unchanged. The adhesion of ethylene resin, propylene resin and ethylene, propylene binary copolymer resins increases significantly. The resin (POE) resin synthesized under the conditions of metallocene catalysis of ethylene and butene, ethylene and octene, and ethylene and hexene has the largest increase in adhesion. Based on this, the present invention adopts polyolefin resins, that is, adopts ethylene resin, propylene resin and binary resins of ethylene, propylene, butene, octene and hexene copolymerization.

[0057] Secondly, the addition of amide wax cannot completely replace non-modified wax because the presence of amide groups in amide wax significantly reduces the curing speed of amide wax. In order to ensure the curing speed of hot melt adhesive, non-modified wax and amide wax need to be used in combination.

[0058] Thirdly, in the selection of tackifying resin, terephthalate phenol resin and phenolic resin are used. The presence and content of benzene ring have a great influence on the cohesive strength.

[0059] Finally, due to the high melting point of amide wax, in the preparation method of hot melt adhesive, the melting temperature is 150-170°C to ensure the melting of amide wax and uniform mixing.

[0060] The following is a detailed description of each raw material:

[0061] Polyolefin resin

[0062] Polyolefin resin refers to hot melt grade ethylene polymer resin that can be used in the field of hot melt adhesives. Ethylene polymer resin is a homopolymer based on ethylene and polymerized with a monomer such as ethylene, propylene, butene, octene, hexene, etc., such as polyethylene, ethylene-propylene copolymer resin, copolymer resin of ethylene and 1-octene, copolymer resin of ethylene and butene, copolymer resin of ethylene and hexene, etc. Preferably, the polyolefin resin is a POE elastomer resin (catalyzed by metallocene), that is, one or more of a binary copolymer resin of ethylene and 1-octene, a binary copolymer resin of ethylene and butene, and a binary copolymer resin of ethylene and hexene.

[0063] Unmodified wax

[0064] The non-modified wax may be a conventional component in the art for adjusting the melt viscosity of hot melt adhesives, including but not limited to Fischer-Tropsch wax, microcrystalline wax, polyethylene wax, paraffin wax, and the like.

[0065] Amide wax

[0066] Amide wax is a wax containing an amide group, with a melting point of less than 160°C. It is formed by a dehydration reaction of a difunctional primary amine and a monofunctional straight-chain acid (such as stearic acid). The reaction formula is as follows:

[0067] 2R1-COOH+H2N-R2-NH2→R1-(CO)-HN-R2-NH-(CO)-R1+2H2O

[0068] Wherein, R1 is selected from a C12-C30 straight chain alkyl group, and R2 is selected from a C1-C10 straight chain alkylene group. The number of carbon atoms of R2 is a positive integer even number for easy melting; the number of carbon atoms of R1 is ≥12, in order to ensure that the synthetic product has higher wax properties, that is, faster curing properties.

[0069] Oil

[0070] The oil may be any oil component known in the art that can be used as a raw material for hot melt adhesive, including but not limited to white oil, polyisobutylene, paraffin oil, etc.

[0071] Tackifying resin

[0072] The tackifying resin is a tackifying resin containing phenolic hydroxyl groups, including but not limited to terephthalate phenol resin, phenolic resin, etc.

[0073] Preferably, the phenolic hydroxyl content of the tackifying resin is 20-300 mgKOH / g (HG / T 2709), and the phenol content is not more than 20 mg / kg (GB / T 30773); further preferably, the phenolic hydroxyl content of the tackifying resin is 30-100 mgKOH / g, and the phenol content is not more than 10 mg / kg.

[0074] Isocyanate

[0075] Isocyanates include, but are not limited to, diphenylmethane diisocyanate (MDI-100), prepolymers formed by reacting diphenylmethane diisocyanate (MDI-100) with polyols (polyesters, polyethers or a mixture of the two), and their (MDI-100, MDI-100 prepolymer) phenolic blocked derivatives.

[0076] The phenol blocked derivative is a product of a complete or partial addition reaction of a monofunctional phenol blocking agent (except phenol in the tobacco industry), including but not limited to methylphenol, methoxyphenol, bromophenol, etc., with diphenylmethane diisocyanate (MDI-100); it is liquid at 150-160°C and has no odor.

[0077] Preferably, the ratio of the molar number of isocyanic acid in the isocyanate to the molar number of phenolic hydroxyl groups in the tackifying resin is 1:(0.5-1.5), preferably 1:(0.8-1.2), and more preferably 1:(0.98-1.05).

[0078] Antioxidants

[0079] The antioxidant may be any auxiliary agent known in the art that can play an antioxidant role, including but not limited to pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (1010), 2,6-di-tert-butyl-p-cresol (BHT), etc.

[0080] In some embodiments, the method for preparing the polyolefin hot melt adhesive comprises the following steps:

[0081] (1) Add raw material high molecular weight resin, non-modified wax, amide wax, oil, tackifying resin, and antioxidant into a container in sequence according to the raw material metering ratio; gradually start stirring during the addition process (the raw materials are in a solid-liquid mixed state that can be stirred), and heat to 150-170° C. After reaching the temperature, the stirring speed is not less than 100 r / min;

[0082] (2) Start vacuum decompression, the vacuum degree should not be less than -0.08MPa. After 60 minutes, start to test the melt viscosity and moisture content. When the melt viscosity reaches the design value and the moisture content is less than 200ppm, release the vacuum and cool to 5-10℃ above the softening point. Add isocyanate and stir for 20 minutes. Stir under vacuum for 10 minutes, discharge and seal.

[0083] The above preparation method includes an addition reaction between isocyanate and phenolic hydroxyl group, and the chemical reaction formula is as follows:

[0084]

[0085] It should be noted that this reaction is reversible.

[0086] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0087] The experimental methods in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are conventional biochemical reagents and can be obtained from commercial sources unless otherwise specified.

[0088] Example 1 (Comparative Example 1)

[0089] Example 1 (Comparative Example 1) is the ratio of Example 2 disclosed in "Patent Publication No.: CN117363285A, Invention Name: A Hot Melt Adhesive for Overlapping of Oil-Resistant Filter Rod Forming Paper and Preparation Method thereof" (see Table 1), and its preparation process is as follows:

[0090] ① Add EVA resin, Fischer-Tropsch wax, polyisobutylene, phenolic tackifying resin, C5 hydrogenated petroleum resin and antioxidant into the container according to the raw material measurement ratio;

[0091] ② During the process of adding materials in step ①, stirring is gradually started (the raw materials are in a solid-liquid mixed state that can be stirred), and the temperature is raised to 100-130°C. After reaching the temperature, the stirring speed is not less than 100r / min;

[0092] ③ Turn on the vacuum decompression, the vacuum degree should not be lower than -0.08MPa. After 60 minutes, start to detect the melt viscosity and water content. When the melt viscosity reaches 1500±500mPa.s (150℃), and the water content is less than 200ppm, release the vacuum and cool to 115℃, add MDI-100, stir for 20 minutes, vacuum stir for 10 minutes, discharge the material, and seal it.

[0093] Embodiment 2-7

[0094] Examples 2-7 are the ratios (2, 4 and 5) disclosed in the present invention and similar examples (3, 6 and 7) (see Table 1), and their preparation processes are as follows:

[0095] ① Add polyolefin resin, non-modified wax, amide wax (zero in Example 7), polyisobutylene, phenolic tackifying resin, and antioxidant into a container according to the raw material metering ratio;

[0096] ② During the process of adding materials in step ①, stirring is gradually started (the raw materials are in a solid-liquid mixed state that can be stirred), and the temperature is raised to 160°C. After reaching the temperature, the stirring speed is not less than 100r / min;

[0097] ③ Turn on the vacuum decompression, the vacuum degree should not be lower than -0.08MPa. After 60 minutes, start to detect the melt viscosity and water content. When the melt viscosity reaches (1800-2300) ±500mPa.s (150℃), and the water content is less than 200ppm, release the vacuum and cool to 115℃, add MDI-100, stir for 20 minutes, vacuum stir for 10 minutes, discharge the material, and seal it.

[0098] The specific formula is shown in Table 1.

[0099] Table 1

[0100]

[0101] Note: Phenolic hydroxyl value of ECOGREEN / H150: 145mgKOH / g

[0102] Test example:

[0103] The basic performance test and machine experiment data of the embodiment are shown in Table 2.

[0104] Table 2

[0105]

[0106] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. In addition, the various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A composition for preparing a polyolefin hot melt adhesive, the composition comprising a polyolefin resin, a non-modified wax, an amide wax, a tackifying resin, an isocyanate, an antioxidant and an optional oil.

2. The composition according to claim 1, characterized in that The amide wax includes a compound having a structure shown in formula (I); Wherein, R1 is selected from a C12-C30 straight chain alkyl group; R2 is selected from a C1-C10 straight chain alkylene group; Preferably, the amide wax is obtained by dehydration reaction of a C1-C10 difunctional primary amine and a C12-C30 monofunctional linear acid; Preferably, the melting point of the amide wax is higher than 80°C, preferably 80-160°C, more preferably 120-150°C.

3. The composition according to claim 1 or 2, characterized in that The non-modified wax is selected from one or more of Fischer-Tropsch wax, microcrystalline wax, polyethylene wax or paraffin wax; Preferably, the mass ratio of the amide wax to the non-modified wax is 1:(0.5-10), preferably 1:(1-10).

4. The composition according to any one of claims 1 to 3, characterized in that The polyolefin resin includes one or more of polyethylene, polypropylene, binary copolymer resin of ethylene and propylene, binary copolymer resin of ethylene and 1-octene, binary copolymer resin of ethylene and butene, or binary copolymer resin of ethylene and hexene; preferably, the polyolefin resin is selected from POE elastomer resin; and / or The tackifying resin is selected from one or both of terephthalate phenol resin and phenolic resin; preferably, the phenolic hydroxyl content of the tackifying resin is 20-300 mgKOH / g, preferably 30-100 mgKOH / g; preferably, the phenol content of the tackifying resin is not more than 20 mg / kg; and / or The isocyanate is one or more selected from diphenylmethane diisocyanate or its phenolic blocked derivatives, prepolymers formed by the reaction of diphenylmethane diisocyanate and polyols, or phenolic blocked derivatives thereof; preferably, the phenolic blocked derivative is a product of a total or partial addition reaction of a monofunctional phenolic blocking agent with diphenylmethane diisocyanate, and the monofunctional phenolic blocking agent includes one or more of methylphenol, methoxyphenol or bromophenol; and / or The antioxidant is one or more selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 2,6-di-tert-butyl-p-cresol; and / or The oil includes one or more of white oil, polyisobutylene or paraffin oil; Preferably, the molar ratio of the number of moles of isocyanic acid in the isocyanate to the number of phenolic hydroxyl groups in the tackifying resin is 1:(0.5-1.5), preferably 1:(0.8-1.2), and more preferably 1:(0.98-1.05).

5. The composition according to any one of claims 1 to 4, characterized in that The polyolefin hot melt adhesive comprises the following components by weight:

6. A polyolefin hot melt adhesive, wherein the polyolefin hot melt adhesive is prepared from the composition according to any one of claims 1 to 6.

7. A method for preparing a polyolefin hot melt adhesive, the method comprising the following steps: (1) mixing a polyolefin resin, a non-modified wax, an amide wax, a tackifying resin, an antioxidant and an optional oil to obtain a mixture; (2) reacting the mixture with isocyanate to obtain the polyolefin hot melt adhesive.

8. The preparation method according to claim 7, characterized in that: In step (1), the mixing temperature is 150-170°C, the vacuum degree is not less than -0.08MPa, and the stirring speed is not less than 100r / min; and / or The water content of the mixture is less than 200 ppm, the vacuum is released and the temperature is lowered to 5-10° C. above the softening point, and isocyanate is added to carry out the reaction; and / or In step (2), the reaction time is 10-60 min. Preferably, the mixture is reacted with isocyanate for 5-40 min and then reacted under vacuum for 5-20 min.

9. Use of the polyolefin hot melt adhesive according to claim 6 or the polyolefin hot melt adhesive prepared by the method according to claim 7 or 8 in overlap bonding, especially in overlap bonding of oil-resistant molded paper filter rods.

10. A filter rod, wherein the overlapped ends of the filter rod are bonded by the polyolefin hot melt adhesive according to claim 6 or the polyolefin hot melt adhesive prepared by the method according to claim 7 or 8; Preferably, the filter rod comprises an oil-resistant plug paper filter rod; More preferably, the filter plug comprises an oil-resistant plug paper filter plug used in tobacco production.

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