Hot melt adhesive composition for safe paper packaging

Abstract

The present invention relates to a hot melt adhesive composition for paper protective packages containing a plasticizer blend, the use of said hot melt adhesive composition in paper protective packages, and an article manufactured using the hot melt adhesive composition of the present invention.

Description

Technical Field

[0001] The present invention relates to a hot melt adhesive composition for a safe paper packaging or a secured paper packaging containing a plasticizer blend, the use of the hot melt adhesive composition in a paper protective package, and a product manufactured using the hot melt adhesive composition of the present invention.

Background Art

[0002] Packaging waste accounts for a large portion of the world's waste. Therefore, the development and promotion of sustainable alternatives to reduce the amount of packaging waste is one of the challenges in today's industry, especially in light of the increasing e-commerce. Paper has emerged as an environmentally friendly and sustainable alternative to plastic. Therefore, there is a high demand for paper packaging and various materials to support the production of appropriate packaging products.

[0003] Hot melt adhesives have been found to be suitable adhesives for the production of paper packages due to their solvent-free nature, rapid adhesion formation, and cost efficiency.

[0004] US5747573 discloses a high heat resistance hot melt adhesive composition comprising a) about 20 to 80 parts by weight of an adhesive of an amorphous polyalphaolefin butene-propylene-ethylene terpolymer, b) about 5 to 40 parts by weight of an adhesive of a solid benzoate plasticizer, and c) about 10 to 70 parts by weight of an adhesive of a tackifier, and the adhesive composition has a peel value at elevated temperature exceeding 70 °C (160 °F).

[0005] US5627229 refers to a hot melt adhesive composition comprising 5 to 40% by weight of cyclohexanedimethanol dibenzoate plasticizer, 20 to 80% by weight of an adhesive resin selected from the group consisting of aromatic tackifying resins, aromatic-aliphatic tackifying resins, aliphatic tackifying resins, rosin-derived tackifying resins and mixtures thereof, and 5 to 35% by weight of a thermoplastic polymer, wherein the composition cold flows for a controllable period at ambient temperature after application and before its modulus of elasticity increases. The hot melt adhesive composition can be used, for example, for fixing cigarette cartons, assembling cartons, or manufacturing disposable articles.

[0006] US5853864 describes an article resistant to moisture-induced delamination, consisting of a substrate joined to a second layer by a spray adhesive, comprising: a) 10 to 40 parts by weight of a thermoplastic block copolymer selected from the group consisting of A-B block copolymers, A-(B-A) n -B-A block copolymers (where n is an integer of 1 or more), and radial block copolymers, each A comprising a polystyrene block and each B comprising a rubbery block; b) 30 to 75 parts by weight of a tackifying resin selected from the group consisting of rosin-derived tackifying resins, aliphatic tackifying resins, aromatic-aliphatic mixed tackifying resins and mixtures thereof; and c) 5 to 40 parts by weight of cyclohexanedimethanol dibenzoate plasticizer, wherein after the adhesive is sprayed and cooled to ambient temperature, the adhesive retains sufficient fluidity for a sufficient time to wet or penetrate the substrate or the second layer to form a moisture-resistant bond. In a specific example of US5853864, a large amount of cyclohexanedimethanol dibenzoate plasticizer is used, but in this case, the open time becomes very short and the adhesiveness to paper deteriorates. Therefore, the composition disclosed therein is not suitable for the uses disclosed in the context of the present invention, namely safe paper packaging. As is clear from US5853864, quite different uses of the adhesive composition disclosed therein are envisioned.

[0007] US6034159 discloses a hot melt adhesive for multipurpose bookbinding, which comprises: a) about 25% to about 40% by weight of a styrene - isoprene - styrene block copolymer with a styrene content between about 15% and about 35%; b) about 25% to about 50% by weight of at least one compatible tackifying resin selected from the group consisting of rosin and rosin esters, terpenes and modified terpenes, aliphatic, alicyclic and aromatic hydrocarbons, hydrogenated derivatives, and mixtures thereof; c) about 10% to about 30% by weight of a synthetic high melting point wax having a melting point above about 90°C; d) about 5% to about 30% by weight of a solid benzoate plasticizer; e) up to about 25% of a compatible wax selected from the group consisting of paraffin wax, microcrystalline wax, and mixtures thereof; and f) up to about 15% of a compatible polymer selected from the group consisting of homopolymers, copolymers, and terpolymers of ethylene, homopolymers, copolymers, and terpolymers of propylene, rubbery block copolymers, and mixtures thereof.

[0008] US5026756 discloses a solid non - aqueous hot melt adhesive composition comprising a polymer, a tackifier, and 1,4 - cyclohexanedimethanol dibenzoate in a plasticized amount in the range of about 5 - 40% by weight.

[0009] US5624986 relates to a hot melt adhesive composition comprising the following components: (a) about 5 - 50% by weight of a plasticizer comprising a cycloaliphatic or aromatic ester of benzenedicarboxylic acid or a cycloaliphatic polyester of an aromatic carboxylic acid, which is solid at room temperature; (b) about 20 - 80% by weight of a tackifier selected from the group consisting of aromatic tackifying resins, aromatic - aliphatic tackifying resins, aliphatic tackifying resins, and rosin - derived tackifying resins, and mixtures thereof; and (c) about 0 - 55% by weight of a thermoplastic polymer; wherein the composition cold - flows for a controllable period at ambient temperature after application and cooling and before the increase in storage modulus (G').

Prior Art Documents

Patent Documents

[0010] [Patent Document 1] U.S. Patent No. 5,747,573 [Patent Document 2] U.S. Patent No. 5,627,229 [Patent Document 3] U.S. Patent No. 5,853,864 [Patent Document 4] U.S. Patent No. 6,034,159 [Patent Document 5] U.S. Patent No. 5,026,756 [Patent Document 6] U.S. Patent No. 5,624,986 [Summary of the Invention] [Problems to be Solved by the Invention]

[0011] However, existing hot melt technologies and products have insufficient adhesion to high-density paper and lack heat resistance and adhesion safety within the general operating temperature range of -20 to 50°C, and thus have been found to be unable to meet the requirements of recently developed e-commerce paper packaging applications. High-performance hot melt adhesives exhibit good adhesion performance to paper but cannot ensure the adhesion process. Rather, paper packaging can be opened and resealed, which is undesirable for protected paper packaging.

[0012] Therefore, there remains a need for an adhesive composition that enables the production of safe paper packaging and is preferably suitable for use in high-speed automated packaging lines. [Means for Solving the Problems]

[0013] Surprisingly, it has been found that this need can be met by a hot melt adhesive composition comprising a plasticizer blend.

[0014] There is provided a hot melt adhesive composition comprising the following, based on the total weight of the composition: a) 10 to 60% by weight of a thermoplastic block copolymer, b) 30 to 70 wt% of tackifier, and c) 2 to 40 wt% of plasticizer blend, wherein the plasticizer blend comprises a solid plasticizer P1 in an amount up to 20 wt% and a liquid plasticizer P2, based on the total weight of the composition. The preferred range of the solid plasticizer P1 has been found to be 5 wt% to 16 wt% based on the total weight of the composition. Thus, the lower limit of the plasticizer range is preferably at least 5 wt% considering the presence of the liquid plasticizer P1.

[0015] Surprisingly, the hot melt adhesive composition of the present invention exhibited a desirable combination of a long open time and reliable adhesion. After adhesion, the adhesive composition of the present invention became hard and exhibited excellent cohesion and heat resistance, and as a result, it was observed that the packaging paper was destructively torn during opening. Due to this combination of properties, it has been found that the hot melt adhesive of the present invention is suitable for use in an automatic packaging line and at the same time meets the requirements of safe paper packaging.

Mode for Carrying Out the Invention

[0016] The solid plasticizer referred to in the present invention means a plasticizer that is solid at room temperature and preferably has a melting point exceeding 25°C. The liquid plasticizer in the context of the present invention refers to a plasticizer that is liquid at room temperature. The melting point can be measured by DSC (Differential Scanning Calorimetry). Room temperature in the context of the present invention refers to the temperature range of 20 to 23°C. Therefore, those skilled in the art will understand that the solid plasticizer and the liquid plasticizer used in the present invention are different from each other.

[0017] In the process of the present invention, the hot melt adhesive composition, the adhesive composition, the composition of the present invention and the composition are used synonymously unless otherwise specified.

[0018] The hot melt composition of the present invention comprises a thermoplastic copolymer, a tackifier and a plasticizer blend. Details of each component will be described later:

[0019] a) Thermoplastic block copolymer The hot melt adhesive of the present invention contains 10 to 60% by weight, preferably 20 to 40% by weight, of a thermoplastic copolymer based on the total weight of the hot melt adhesive composition. The thermoplastic block copolymer is preferably an A-B-A block copolymer, (A-B) n, or A-(B-A) n -B-A block copolymer selected from the group consisting of, where n is an integer of 1 or more, each A contains a polystyrene block, and each B contains a rubbery block. The A block is preferably homopolymer polystyrene. However, other vinyl aromatic monomers can also be used in the preparation of plastics or glassy ends or A blocks of homopolymers or copolymers. The B block usually contains a rubbery polymer derived from a diene monomer containing isoprene or butadiene. The mid-block is post-treated by hydrogenation or other treatments (i.e., SEPS from hydrogenated SIS, or SEBS from hydrogenated SBS, etc.) to improve thermal stability. In a preferred embodiment, the thermoplastic copolymer is a blend of styrene-isoprene-styrene copolymer (SIS) or SIS and styrene-butadiene-styrene block copolymer (SBS). In a preferred embodiment, the SIS and / or SB block copolymer can also be hydrogenated.

[0020] In a preferred embodiment, the block copolymer is provided as a blend of polymers, and the blend preferably further comprises one or more polymers selected from the group consisting of styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer (SEPS), ethylene-vinyl acetate copolymer (EVA), or copolymers and polymers derived from olefins.

[0021] In a preferred embodiment, the block copolymer is a blend of styrene-isoprene-styrene copolymer (SIS), or SIS and styrene-butadiene-styrene block copolymer (SBS), or a blend of SIS and styrene-butadiene-styrene block copolymer (SBS) with SEBS or / and SEPS, EVA or polyolefin polymer.

[0022] In a preferred embodiment, the block copolymer is a linear SI block copolymer optionally containing SBS blocks, with a styrene content of 12 to 50%, preferably 15 to 45%. The block copolymer may be a blend of two or more, preferably two or three, linear SI block copolymers optionally containing SBS blocks, with a styrene content of 12 to 50%, preferably 15 to 45%.

[0023] The styrene content in the adhesive composition of the present invention is preferably 15 to 45% by weight based on the total weight of the composition. In a preferred embodiment, the styrene content in the composition is achieved by using a mixture of a high styrene content SIS block copolymer and a low styrene content SIS block copolymer.

[0024] b) Tackifier The hot melt adhesive composition of the present invention contains 30 to 70% by weight, preferably 40 to 65% by weight, of a tackifier based on the total weight of the composition.

[0025] In a preferred embodiment, the tackifier is selected from the group consisting of aliphatic, cycloaliphatic and aromatic hydrocarbon resins and their hydrogenated derivatives, rosin and rosin derivatives, terpenes and modified terpenes, and mixtures thereof.

[0026] Tackifiers useful in the adhesives of the present invention include rosin derivatives containing wood rosin, tall oil, tall oil derivatives, rosin ester resins, natural and synthetic terpenes, aliphatic or mixed aromatic-aliphatic tackifying resins.

[0027] The aromatic monomers useful for forming the aliphatic-aromatic adhesive composition of the present invention can be prepared from any monomer containing a substantial aromatic character and a polymerizable unsaturated group. Representative examples of such aromatic monomers include styrene, alpha-methylstyrene, vinyltoluene, methoxystyrene, t-butylstyrene, chlorostyrene, etc. of styrene-based monomers, and indene, methylindene, etc. of indene-based monomers. Aliphatic monomers are usually natural and synthetic terpenes containing C5 and C6 cyclohexyl or cyclopentyl saturated groups, and can further contain various ring substituents that are substantially aliphatic. The aliphatic pressure-sensitive adhesive resin can be produced by polymerizing a feed stream containing sufficient aliphatic monomers such that the resulting resin exhibits aliphatic properties. Such a feed stream can include other aliphatic unsaturated monomers such as 1,3-butadiene, cis-1,3-pentadiene, trans-1,3-pentadiene, 2-methyl-1,3-butadiene, 2-methyl-2-butene, cyclopentadiene, dicyclopentadiene, terpene monomers, etc. The mixed aliphatic-aromatic resin contains sufficient aromatic monomers and sufficient aliphatic monomers, and optionally other C3-C8 unsaturated monomers, to produce a resin having both aliphatic and aromatic properties.

[0028] The adhesive composition of the present invention can contain rosin and rosin derivatives as tackifiers. Rosin is a solid substance naturally contained in the resin of pine trees, and is usually derived from the resin extrudate of living trees, old stumps, and tall oil produced as a byproduct of kraft paper manufacturing. After rosin is obtained, it can be subjected to treatments such as hydrogenation, dehydrogenation, polymerization, and esterification. Rosin is usually classified as gum rosin, wood rosin, and tall oil rosin. These materials can be used without modification, can also be used in the form of esters of polyhydric alcohols, and can also be polymerized by the inherent unsaturation of the molecules. These materials are commercially available and can be mixed into the adhesive composition using standard mixing techniques.

[0029] Typical examples of such rosin derivative tackifying resins include pentaerythritol esters of tall oil, gum rosin, wood rosin, or mixtures thereof.

[0030] Typical examples of such aliphatic resins include hydrogenated synthetic C9 resins, synthetic branched and unbranched C5 resins, and mixtures thereof.

[0031] Typical examples of such aromatic-aliphatic tackifying resins include styrenated terpene resins, styrenated C5 resins, or mixtures thereof.

[0032] The resin of the tackifier can be selected from fully hydrogenated hydrocarbon resins, partially hydrogenated hydrocarbon resins, or mixtures thereof, preferably a mixture.

[0033] In a particularly preferred embodiment, the tackifying resin is selected from one or more of the following categories: i) Hydrocarbon resins having C5 units, hydrogenated DCPD (dicyclopentadiene) resins, C9-modified hydrogenated DCPD resins, C9-modified hydrocarbon resins having C5 units, hydrogenated resins having C5 units; ii) Terpene resins; iii) Partially hydrogenated C9 type aromatic resins.

[0034] c) Plasticizer The hot melt adhesive composition according to the present invention is characterized in particular by a plasticizer blend contained in the composition in an amount of more than 5 to 40% by weight, typically more than 5 to 35% by weight, preferably 5.5 to 35% by weight, more preferably 7 to 30% by weight, most preferably 7 to 26% by weight, based on the total weight of the composition. The plasticizer blend includes a first plasticizer P1 that is solid at room temperature and a second plasticizer P2 that is liquid at room temperature. Without being bound by theory, it is believed that the plasticizer blend applied to the hot melt adhesive of the present invention provides a preferred combination of a long open time and high adhesive strength observed in the hot adhesive composition of the present invention.

[0035] In a preferred embodiment, the first plasticizer P1 compound has a melting point of at least 60 °C, preferably at least 80 °C. In a more preferred embodiment, the plasticizer P1 is a benzoate plasticizer containing a cycloaliphatic or aromatic ester of benzenedicarboxylic acid, or a cycloaliphatic polyester of aromatic carboxylic acid, and is solid at room temperature. In a particularly preferred embodiment, the plasticizer P1 is 1,4-cyclohexanedimethanol benzoate.

[0036] It is advantageous that the amount of the first plasticizer P1 in the adhesive composition is 16% by weight or less based on the total weight of the adhesive composition. Surprisingly, it has been found that restricting the amount of the first plasticizer P1 within the claims further improves the performance of the adhesive composition. Preferably, the first plasticizer P1 is present in the adhesive composition in an amount of 15% by weight or less based on the total weight of the adhesive composition. Suitably, the first plasticizer P1 is present in the adhesive composition in an amount in the range of 5% to 15% by weight based on the total weight of the adhesive composition.

[0037] The plasticizer blend further comprises a second plasticizer P2 that is liquid at room temperature. In a preferred embodiment, the plasticizer P2 is included in the adhesive composition in an amount of at most 10% by weight, preferably 0.5 to 10% by weight, based on the total weight of the adhesive composition.

[0038] Those skilled in the art will understand that changes in the amounts of P1 and P2 (and other plasticizers present in the plasticizer blend) will affect the total amount of the plasticizer blend. For example, the amount of the plasticizer blend in a preferred composition according to the present invention can be 7% or 8% or 9% or 10% or 11% or 12% or 13% or 14% or 15% or 16% or 17% or 18% or 19% or 20% or 21% or 22% or 23% or 24% or 25% or 26% by weight based on the total weight of the composition. When the plasticizers present in the composition according to the present invention are only P1 and P2, the total amount of the plasticizer blend is equal to the amounts of P1 and P2.

[0039] The liquid plasticizer P2 is preferably selected from naphthenic mineral oil and / or paraffinic mineral oil.

[0040] The hot melt adhesive composition of the present invention may contain additional components such as stabilizers and antioxidants. In a preferred embodiment, the amount of additional components (i.e., components other than the thermoplastic block copolymer, tackifier; solid plasticizer P1 and liquid plasticizer P2) in the composition is 0.3 to 1% by weight or less based on the total weight of the composition.

[0041] Suitable antioxidants include, for example, hindered phenols, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.

[0042] The hot melt adhesive composition has many advantageous properties such as a long open time and strong adhesive strength. In a preferred embodiment, the composition of the present invention is characterized by at least one of the following properties: i) An open time of 30 to 240 seconds, preferably 90 to 210 seconds; ii) The heat resistance temperature range is -20 to 50°C; iii) Tearing of fibers during high-speed and low-speed peeling.

[0043] The adhesive composition according to the present invention exhibits a surprisingly long open time, a wider operating window, and strong adhesion to high-density paper, and is particularly suitable for paper packaging. Furthermore, the composition according to the present invention exhibits excellent adhesive performance in a wide temperature range, for example, from -30°C to 50°C, and also exhibits excellent cohesive strength at high temperatures up to 50°C, for example. Therefore, a further object of the present invention is to use the hot melt adhesive composition according to the present invention in paper packaging, preferably in an automated paper packaging line.

[0044] Due to the improved adhesive strength, the paper packaging sealed with the hot melt adhesive composition of the present invention cannot be resealed and is particularly useful for secure paper packaging. Therefore, the hot melt adhesive composition of the present invention is preferably used in the manufacture of secure paper packaging.

[0045] A further object of the present invention is an article comprising at least two layers adhered to each other by a hot melt adhesive composition according to the present invention. Preferably, at least one of these layers contains cellulose fibers. In a particularly preferred embodiment, the article is selected from the group consisting of a sealable paper bag, in particular a paper bag capable of holding a weight of up to 2 kg, and a safe paper package.

[0046] From the above, it is clear that the present invention can be defined according to one or more of the following descriptions: 1. Based on the total weight of the composition, a) 10 to 60% by weight of a thermoplastic block copolymer, b) 30 to 70% by weight of a tackifier, and c) more than 5 to 40% by weight of a plasticizer blend, The plasticizer blend contains a solid plasticizer P1 in an amount in the range of 5% to 16% by weight based on the total weight of the composition and a liquid plasticizer P2, and is characterized by a hot melt adhesive composition.

[0047] 2. The thermoplastic block copolymer is selected from the group consisting of an A-B-A block copolymer, (A-B) n, or A-(B-A) n -B-block copolymer, n is an integer of 1 or more, each A comprises a polystyrene block, and each B comprises a rubbery block, and is characterized by the hot melt adhesive composition according to description 1.

[0048] 3. The thermoplastic copolymer is a styrene-isoprene-styrene copolymer (SIS), and is characterized by the hot melt adhesive composition according to description 1 or 2.

[0049] 4. The thermoplastic copolymer is a blend of SIS and a styrene-butadiene-styrene block copolymer (SBS), and is characterized by the hot melt adhesive composition according to description 1 or 2.

[0050] 5. The hot melt adhesive composition according to claim 1 or 2, wherein the thermoplastic copolymer is a blend of SIS and a styrene-butadiene-styrene block copolymer (SBS), and SEBS and / or SEPS, EVA or a polyolefin polymer.

[0051] 6. The hot melt adhesive composition according to any of the preceding descriptions, wherein the tackifier is selected from the group consisting of aliphatic, cycloaliphatic and aromatic hydrocarbon resins and their hydrogenated derivatives, rosins and rosin derivatives, terpenes and modified terpenes and mixtures thereof.

[0052] 7. The hot melt adhesive composition according to any of the preceding descriptions, wherein the tackifier is a fully hydrogenated hydrocarbon resin, a partially hydrogenated hydrocarbon resin, or a blend thereof.

[0053] 8. The hot melt adhesive composition according to claim 7, wherein the tackifier is a blend of a fully hydrogenated hydrocarbon resin and a partially hydrogenated hydrocarbon resin.

[0054] 9. The hot melt adhesive composition according to any of the preceding descriptions, wherein the tackifying resin is selected from one or more of the following categories: i) Hydrocarbon resins having C5 units, DCPD (dicyclopentadiene) hydrogenated resins, C9 modified DCPD hydrogenated resins, C9 modified hydrocarbon resins having C5 units, hydrogenated resins having C5 units; ii) Terpene resins; iii) Partially hydrogenated C9 aromatic resins.

[0055] 10. The hot melt adhesive composition according to any of the preceding descriptions, wherein the first plasticizer P1 is a benzoic acid-based plasticizer comprising a cycloaliphatic ester or an aromatic ester of benzenedicarboxylic acid that is solid at room temperature.

[0056] 11. The first plasticizer P1 is a cycloaliphatic polyester of an aromatic carboxylic acid and is characterized by being solid at room temperature, the hot-melt adhesive composition according to any of the preceding descriptions.

[0057] 12. The plasticizer P1 is 1,4-cyclohexanedimethanol benzoate, the hot-melt adhesive composition according to description 10.

[0058] 13. The solid plasticizer P1 is present in an amount in the range of 5% to 15% by weight based on the total weight of the composition, the hot-melt adhesive composition according to any of the preceding descriptions.

[0059] 14. The solid plasticizer P1 is present in an amount in the range of 7% to 14% by weight based on the total weight of the composition, the hot-melt adhesive composition according to any of the preceding descriptions.

[0060] 15. The plasticizer P2 is contained in the adhesive composition in an amount of 0.1 to 10% by weight based on the total weight of the adhesive composition, the hot-melt adhesive composition according to any of the preceding descriptions.

[0061] 16. The plasticizer P2 is contained in the adhesive composition in an amount of 0.5 to 7% by weight based on the total weight of the adhesive composition, the hot-melt adhesive composition according to any of the preceding descriptions.

[0062] 17. The liquid plasticizer P2 is selected from naphthenic oil and / or paraffinic oil, the hot-melt adhesive composition according to any of the preceding descriptions.

[0063] 18. The plasticizer blend c) consists of plasticizers P1 and P2, and the composition does not contain other plasticizers, the hot-melt adhesive composition according to any of the preceding descriptions.

[0064] 19. The composition has the following properties: i) An open time of 30 seconds to 240 seconds; ii) The heat resistance temperature range is -20 to 50 °C; The hot melt adhesive composition according to any of the preceding descriptions, characterized in that it is characterized by at least one of .

[0065] 20. Use of the hot melt adhesive composition according to any of descriptions 1 to 19 in paper packaging, preferably in an automatic paper packaging line.

[0066] 21. Use according to description 20 in the manufacture of a safe paper packaging material.

[0067] 22. An article comprising at least two layers adhered to each other with the hot melt adhesive composition according to any of descriptions 1 to 19.

[0068] 23. The article according to description 22, characterized in that at least one of these layers contains cellulose fibers.

[0069] 24. The article according to description 22 or 23, characterized in that the article is selected from the group consisting of a sealable paper bag, in particular one that can hold a weight of up to 2 kg, and a safe paper packaging. The present invention will be described in more detail with reference to the following examples, which should not be understood as limiting the scope and spirit of the present invention in any way.

Examples

[0070] Example: The examples in Table 1 below are the preferred components and ranges of the compositions of the present invention. In all cases, since there are no other components in the preparations other than the components described, the total of the described components is 100% by weight.

[0071]

Table 1

[0072] Table 2 compares the composition of the inventive adhesive composition according to the present invention with compositions outside the scope of the compositions described in the claims:

[0073]

Table 2

[0074] The hot melt adhesive composition was tested in various applications and its performance was compared with that of a general hot melt adhesive. Technomelt EM 725 and Technomelt PS 5609 N of Henkel AG&Co.KGaA were used for comparison.

[0075] 1. Dynamic peel test An 18-mm-wide stripe hot melt coating was applied to a 100-mm-wide piece of paper, and the coating weight of the hot melt adhesive was 100 gsm. Then, a second 100-mm-wide paper stripe was pressed with a 2-kg roller for 60 seconds, 120 seconds, or other specified open times to form a bond. A 25-mm-wide bonding paper stripe was cut in the cross direction. The samples were peeled at different speeds. In the case of the composition of the present invention, the desired fiber breakage was observed. The results are summarized in Table 3.

[0076]

Table 3

[0077]

Table 4

[0078]

Table 5

[0079]

Table 6

[0080] 2. Static peel test A 100 mm wide piece of paper was coated with an 18 mm wide stripe of hot melt coating, and the coating weight of the hot melt adhesive was 100 gsm. Then, a second 100 mm wide paper stripe was pressed with a 2 kg roller for 60 seconds, 120 seconds or other specified open time to form a bond. A 25 mm wide bonding paper stripe was cut in the cross direction. One end was hung on the oven rig, and a 100 g weight was attached to the other end to create a 180° peel mode. The static peel test was carried out in an environment at a temperature of 45 °C, and the time <<time>> required for the weight indicating the peeling of the paper piece to decrease was recorded. The results are summarized in Table 4 using a standard density envelope paper of 120 g / m 2 and show that the adhesiveness of the composition of the present invention is significantly improved.

[0081]

Table 7

[0082] It will be understood that the present invention is capable of modification within the scope of the appended claims.

Claims

1. Based on the total weight of the composition, a) 10 to 60% by weight of a thermoplastic block copolymer, b) 30 to 70% by weight of a tackifier, and c) more than 5% to 40% by weight of a plasticizer blend, A hot melt adhesive composition comprising: The plasticizer blend comprises a first solid plasticizer P1 in an amount in the range of 5% to 16% by weight based on the total weight of the composition and a second liquid plasticizer P2, characterized in that it is a hot melt adhesive composition.

2. The thermoplastic block copolymer is selected from the group consisting of an ABA block copolymer, (AB) ｎ、 or A-(BA) ｎ -BA block copolymer, n is an integer of 1 or more, each A contains a polystyrene block, and each B contains a rubbery block, and the hot melt adhesive composition according to claim 1 is characterized in that

3. The thermoplastic copolymer is a styrene-isoprene-styrene copolymer (SIS), or a mixture of SIS and a styrene-butadiene-styrene block copolymer (SBS), or a mixture of SIS and a styrene-butadiene-styrene block copolymer (SBS) and SEBS or / and SEPS, EVA or a polyolefin polymer, characterized in that it is a hot melt adhesive composition according to any one of Claims 1 and 2.

4. The tackifier is selected from the group consisting of aliphatic, cycloaliphatic and aromatic hydrocarbon resins and their hydrogenated derivatives, rosins and rosin derivatives, terpenes and modified terpenes and mixtures thereof, characterized in that it is a hot melt adhesive composition according to any one of Claims 1 to 3.

5. The tackifying resin is selected from one or more of the following categories, characterized in that it is a hot melt adhesive composition according to Claim 4: i) A hydrocarbon resin having C units, a DCPD (dicyclopentadiene) hydrogenated resin, a C-modified DCPD hydrogenated resin, a C-modified hydrocarbon resin having C units, a hydrogenated resin having C units; ５ units, a DCPD (dicyclopentadiene) hydrogenated resin, C ９ modified DCPD hydrogenated resin, C ５ units having C ９ modified hydrocarbon resin, C ５ units; ii) terpene resin; iii) Partially hydrogenated Ｃ９ type aromatic resin.

6. The first plasticizer P1 is a benzoate plasticizer containing a cycloaliphatic or aromatic ester of benzenedicarboxylic acid, or a cycloaliphatic polyester of an aromatic carboxylic acid, and is solid at room temperature, characterized in that it is a hot melt adhesive composition according to any one of Claims 1 to 5.

7. The plasticizer P1 is 1,4-cyclohexanedimethanol benzoate, characterized in that it is a hot melt adhesive composition according to Claim 6.

8. The plasticizer P2 is contained in the adhesive composition in an amount of 0.1 to 10% by weight, preferably 0.5 to 7% by weight, based on the total weight of the adhesive composition, characterized in that it is a hot melt adhesive composition according to any one of Claims 1 to 7.

9. The liquid plasticizer P2 is selected from naphthenic oil and / or paraffin oil, characterized in that it is a hot melt adhesive composition according to any one of Claims 1 to 8.

10. The composition has the following properties i) The open time is 30 to 240 seconds, preferably 90 to 210 seconds; ii) The heat resistance temperature range is -20 to 50 °C The hot melt adhesive composition according to any one of claims 1 to 9, characterized by at least one of the above.

11. Use of the hot melt adhesive composition according to any one of claims 1 to 10 in paper packaging, preferably in an automated paper packaging line.

12. Use of claim 11 in the manufacture of paper protective packages.

13. An article comprising at least two layers adhered to each other using the hot melt adhesive composition according to any one of claims 1 to 10.

14. The article according to claim 13, characterized in that at least one of the layers contains cellulose fibers.

15. The article according to any one of claims 13 or 14, characterized in that it is selected from the group consisting of a sealable paper bag, in particular a paper bag capable of holding a weight of up to 2 kg, and a paper protective package.

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