Hot melt adhesive

Abstract

To provide a hot melt adhesive which can reduce stringing, is excellent in thermal stability, excellent in adhesive property to a paper, and also excellent in heat-resistant creep property and hot tack property.SOLUTION: There is provided a hot melt adhesive comprising: (A) a copolymer of ethylene with an olefin having 3 to 20 carbon atoms; (B) an ethylene-carboxylic acid ester copolymer; and (C) a wax. The (A) copolymer of ethylene with an olefin having 3 to 20 carbon atoms comprises (A1) a metallocene-based copolymer of ethylene with propylene, and the (B) ethylene-carboxylic acid ester copolymer comprises (B1) an ethylene-carboxylic acid ester copolymer which has a structural unit derived from the carboxylic acid ester in an amount of 2 mass% or more and less than 25 mass%, and a melt flow rate of 1 g / 10 min. or more and 400 g / 10 min. or less.SELECTED DRAWING: None

Description

【Technical Field】 【0001】 The present invention relates to a hot melt adhesive, and more particularly, to a hot melt adhesive having good adhesiveness to various substrates, and particularly suitable for assembling paper substrates such as corrugated cardboard. 【Background Art】 【0002】 A hot melt adhesive is a solvent-free adhesive. By heating and melting it and then cooling it after coating on an adherend, it solidifies to exhibit adhesiveness, so instant adhesion and high-speed adhesion are possible, and it is used in a wide range of fields such as paper processing, woodworking, sanitary materials, and the electronics field. 【0003】 As the base polymer of the above hot melt adhesive, depending on its use, for example, ethylene / carboxylic acid ester copolymers such as ethylene-vinyl acetate copolymer (hereinafter also referred to as "EVA") and ethylene-ethyl acrylate copolymer (hereinafter also referred to as "EEA"), polyolefin resins such as polyethylene, polypropylene, and amorphous polyalphaolefin (hereinafter also referred to as "APAO"), synthetic rubbers such as styrene block copolymers (for example, styrene-isoprene-styrene block copolymer (hereinafter also referred to as "SIS"), styrene-butadiene-styrene block copolymer (hereinafter also referred to as "SBS") and their hydrogenated products, and polyurethanes are widely used. 【0004】 When applying a hot melt adhesive, a dedicated coating device called a hot melt applicator is often used. The hot melt applicator has a nozzle as a discharge port. The hot melt adhesive is heated to about 120 to 190 °C and discharged from the tip of the nozzle and applied to the adherend. When applying the hot melt adhesive, a filamentous material of the hot melt adhesive may occur between the tip of the nozzle and the adherend. This filamentous material is caused by the stringiness of the hot melt adhesive and stains the nozzle and the adherend. Therefore, the development of a hot melt adhesive with less stringing is an important responsibility for adhesive manufacturers. 【0005】 Patent documents 1 to 3 disclose hot-melt adhesives containing ethylene / carboxylic acid ester copolymers for the purpose of reducing stringing. 【0006】 Patent Document 1 discloses a hot-melt adhesive comprising a functionalized ethylene-α-olefin copolymer and an ethylene-(meth)acrylic acid ester copolymer (see Claims 1, 0063 to 0066). The hot-melt adhesive described in Patent Document 1 reduces the generation of thread-like material to some extent. However, the thermal stability of the hot-melt adhesive described in Patent Document 1 is not sufficient, and further improvement in thermal stability is required. 【0007】 Patent Document 2 discloses a hot-melt adhesive comprising a polypropylene polymer, an ethylene-α-olefin copolymer, and an ethylene-carboxylic acid ester copolymer having a glass transition temperature of -15°C or lower ([Claim 1]

[0075] to

[0077]

[0091] ). While the hot-melt adhesive of Patent Document 2 can reduce stringing to some extent, it cannot be said to have excellent thermal stability. 【0008】 The hot-melt adhesive described in Patent Document 3 comprises a metallocene-based ethylene / propylene copolymer and an ethylene / carboxylic acid ester copolymer ([Claim 1]

[0109]

[0111] ). Compared to the hot-melt adhesives of Patent Documents 1 and 2, the hot-melt adhesive of Patent Document 3 shows improved stringing reduction and thermal stability, but it cannot be said to fully satisfy the high performance requirements of users. 【0009】 In recent years, users have been requesting hot-melt adhesives that not only reduce stringing and improve thermal stability, but also offer adhesion across a wide temperature range from low to high temperatures, as well as adhesion to substrates coated with chemicals (difficult-to-bond materials). Furthermore, hot melt adhesives are sometimes stored at high temperatures during the summer, or stacked as adhesive blocks at room temperature. Therefore, hot melt adhesives are required to have excellent heat creep resistance and hot tack properties to prevent deformation at high temperatures. [Prior art documents] [Patent Documents] 【0010】 [Patent Document 1] Japanese Patent Publication No. 2019-34999 [Patent Document 2] Japanese Patent Publication No. 2019-116573 [Patent Document 3] Japanese Patent Publication No. 2020-94144 [Overview of the Initiative] [Problems that the invention aims to solve] 【0011】 The present invention aims to provide a hot-melt adhesive that can reduce stringing, has excellent thermal stability, excellent adhesion to paper, and also has excellent heat creep resistance and hot tack properties. [Means for solving the problem] 【0012】 As a result of diligent research, the inventors have found that a hot-melt adhesive containing a specific ethylene / olefin copolymer with 3 to 20 carbon atoms, a specific ethylene / carboxylic acid ester copolymer, and wax can solve the above-mentioned problems, and that such a hot-melt adhesive is suitable for the paper processing and woodworking fields, etc., thus completing the present invention. 【0013】 In other words, this specification includes the following embodiments. 1. (A) Ethylene / olefin copolymer with 3 to 20 carbon atoms, (B) Ethylene / carboxylic acid ester copolymer, (C) wax, (A) Ethylene / olefin copolymer with 3 to 20 carbon atoms, (A1) metallocene-based ethylene / propylene copolymer, (B) A hot melt adhesive comprising an ethylene / carboxylic acid ester copolymer having a content of constituent units derived from (B1) carboxylic acid ester of 2% by mass or more and less than 25% by mass, and a melt flow rate of 1 g / 10 min or more and 400 g / 10 min or less. 2. The hot melt adhesive according to item 1 above, wherein (A) ethylene / olefin copolymer having 3 to 20 carbon atoms contains (A2) metallocene-based ethylene / octene copolymer. 3. The hot melt adhesive according to 1 or 2 above, wherein (A) ethylene / olefin copolymer having 3 to 20 carbon atoms contains (A3) metallocene-based ethylene / hexene copolymer. 4. (A2) The hot melt adhesive according to item 2 above, wherein the metallocene ethylene / octene copolymer comprises a metallocene ethylene / octene copolymer modified with a carboxylic acid and / or carboxylic acid anhydride. 5. (C) A hot melt adhesive as described in any one of items 1 to 4 above, wherein the wax contains Fischer-Tropsch wax. 6. A hot melt adhesive according to any one of items 1 to 5 above, wherein component (B1) is contained in 5 to 60 parts by mass per 100 parts by mass of the total amount of component (A), component (B), and component (C). 7. Furthermore, a hot melt adhesive according to any one of 1 to 6 above, comprising (D) a tackifying resin. 8. Paper products having a hot melt adhesive as described in any one of items 1 to 7 above. [Effects of the Invention] 【0014】 The hot-melt adhesive according to the embodiment of the present invention can reduce stringing, has excellent thermal stability and adhesion to paper, and also exhibits excellent hot tack and heat creep resistance. When applying the hot melt adhesive of the embodiment of the present invention to a substrate such as paper from a nozzle, the nozzle and substrate are not contaminated with thread-like material. Even when the hot melt adhesive is stored in a storage tank for a long period of time, carbonized materials and precipitates are less likely to form. Even when blocks of hot melt adhesive are stacked and stored in a warehouse, the hot melt adhesive blocks can maintain a constant shape without deformation. 【Mode for Carrying Out the Invention】 【0015】 The hot-melt adhesive of the embodiment of the present invention contains, as essential components, (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, and (C) a wax. In the present specification, the "hot-melt adhesive" is an adhesive that is solid at normal temperature but has fluidity when heated and melted, and can be applied, for example, to objects such as a base material and an adherend, and cures and adheres when cooled. 【0016】 <(A) Ethylene / olefin copolymer having 3 to 20 carbon atoms> In the embodiment of the present invention, the "(A) ethylene / olefin copolymer having 3 to 20 carbon atoms" refers to a copolymer of ethylene and an olefin having 3 to 20 carbon atoms, and is not particularly limited as long as the hot-melt adhesive targeted by the present invention can be obtained. 【0017】 Specific examples of the "olefin having 3 to 20 carbon atoms" include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, cis-2-butene, trans-2-butene, isobutylene, cis-2-pentene, trans-2-pentene, 3-methyl-1-butene, 2-methyl-2-butene, and 2,3-dimethyl-2-butene. Olefins having 3 to 10 carbon atoms are preferred, propylene, butene, hexene, and octene are more preferred, propylene, butene, and octene are even more preferred, and octene is particularly preferred. 【0018】 (A) The ethylene / olefin copolymer having 3 to 20 carbon atoms is preferably a copolymer polymerized with a metallocene catalyst. The hot-melt adhesive of the embodiment of the present invention contains the (A) copolymer polymerized with a metallocene catalyst (metallocene-based ethylene / olefin copolymer having 3 to 20 carbon atoms), so that the thermal stability is improved, the adhesiveness at high temperature (60 °C) is excellent, and the heat resistance creep property is improved. 【0019】 (A) Examples of ethylene / olefin copolymers having 3 to 20 carbon atoms include copolymers of ethylene and octene (ethylene / octene copolymer), copolymers of ethylene, propylene, and 1-butene (ethylene / propylene / butene copolymer), copolymers of ethylene and propylene (ethylene / propylene copolymer), and copolymers of ethylene and hexene (ethylene / hexene copolymer). 【0020】 (A) Examples of metallocene ethylene / olefin copolymers having 3 to 20 carbon atoms include (A1) copolymers of ethylene polymerized with a metallocene catalyst and propylene (metallocene propylene / ethylene copolymer), (A2) copolymers of ethylene polymerized with a metallocene catalyst and octene (metallocene ethylene / octene copolymer), and (A3) copolymers of ethylene polymerized with a metallocene catalyst and hexene (metallocene ethylene / hexene copolymer). Commercially available (A) ethylene / olefin copolymers having 3 to 20 carbon atoms can be used. 【0021】 (A1) Examples of metallocene-based ethylene / propylene copolymers include the Vistamax (trade name) series manufactured by ExxonMobil. (A2) Examples of metallocene-based ethylene / octene copolymers include Affinity GA1900 (trade name), Affinity GA1950 (trade name), Affinity GA1875 (trade name), Affinity GA1000R (trade name), Affinity EG8185 (trade name), Affinity EG8200 (trade name), Engage 8137 (trade name), Engage 8180 (trade name), and Engage 8400 (trade name), all manufactured by Dow Chemical. (A3) Examples of metallocene-based ethylene / hexene copolymers include Nipolon Z HM510R manufactured by Tosoh Corporation and Excellen FX402 manufactured by Sumitomo Chemical Co., Ltd. 【0022】 Furthermore, (A) ethylene / olefin copolymer with 3 to 20 carbon atoms may include (A4) copolymer of ethylene and butene (ethylene / butene copolymer) polymerized with a metallocene catalyst, or polymers that have not been polymerized with a metallocene catalyst. (A4) Examples of metallocene-based ethylene / butene copolymers include Excellen FX352 (product name), Excellen FX555 (product name), Excellen FX532 (product name), and Excellen FX558 (product name), all manufactured by Sumitomo Chemical Co., Ltd. 【0023】 A specific example of a polymer not polymerized with a metallocene catalyst is Tuffmer A4085, an ethylene / butene copolymer manufactured by Mitsui Chemicals. Bestplast 730 (trade name) and Bestplast 708 (trade name), manufactured by Evonik Degussa, are ethylene / propylene / 1-butene copolymers. As ethylene / propylene copolymers, Eastoflex E1016PL-1, Aerafin 35, and Aerafin 17 from Eastman Chemical Company, and Lexentac 2304 from Lextac Corporation; Examples include the following. Such copolymers of (A) ethylene and olefins having 3 to 20 carbon atoms can be used alone or in combination. 【0024】 The hot melt adhesive according to the embodiment of the present invention contains (A1) metallocene ethylene / propylene copolymer to improve heat resistance. The (A1) metallocene ethylene / propylene copolymer improves the heat creep resistance, hot tack properties, and thermal stability of the hot melt adhesive. 【0025】 The hot melt adhesive of the embodiment of the present invention preferably contains (A1) a metallocene-based ethylene / propylene copolymer and (A2) a metallocene-based ethylene / octene copolymer. The inclusion of components (A1) and (A2) significantly improves the adhesive performance of the hot melt adhesive in the low-temperature range. 【0026】 (A2) The metallocene ethylene / octene copolymer preferably includes a modified product with a carboxylic acid and / or carboxylic acid anhydride, specifically, for example, "a metallocene ethylene / octene copolymer modified with maleic anhydride by graft polymerization with maleic anhydride." When the hot melt adhesive of the embodiment of the present invention includes "a carboxylic acid and / or carboxylic acid anhydride modified metallocene ethylene / octene copolymer," it exhibits superior adhesion to the substrate to which the agent is applied and superior low-temperature adhesion. A commercially available example of a "maleic anhydride-modified metallocene ethylene / octene copolymer" is Affinity GA1000R (trade name) manufactured by Dow Chemical. 【0027】 <(B) Ethylene / carboxylic acid copolymer> In embodiments of the present invention, "(B) ethylene / carboxylic acid ester copolymer" refers to a copolymer of ethylene and a carboxylic acid ester having an ethylenic double bond, and is not particularly limited as long as it can produce the hot melt adhesive targeted by the present invention. 【0028】 In this specification, examples of "carboxylic acid esters having an ethylenic double bond" include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, as well as vinyl carboxylate and allyl esters such as vinyl acetate and allyl acetate. In this specification, (meth)acrylic acid ester refers to both acrylic acid ester and methacrylic acid ester. 【0029】 In embodiments of the present invention, the "carboxylic acid ester having an ethylenic double bond" preferably includes (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, and more preferably includes methyl (meth)acrylate, ethyl (meth)acrylate, or butyl (meth)acrylate, and is particularly desirable to include methyl methacrylate and ethyl acrylate. 【0030】 Examples of "(B) ethylene / carboxylic acid ester copolymer" include copolymers of ethylene and (meth)acrylic acid ester (ethylene / (meth)acrylic acid ester copolymer), copolymers of ethylene and vinyl carboxylate (ethylene / vinyl carboxylate copolymer), and copolymers of ethylene and allyl carboxylate (ethylene / allyl carboxylate copolymer). Note that the "carboxylic acid" in vinyl carboxylate and allyl carboxylate does not need to have an ethylenic double bond and may be a saturated carboxylic acid. 【0031】 (B) The ethylene / carboxylic acid ester copolymer preferably contains a copolymer of ethylene and (meth)acrylic acid ester (ethylene / (meth)acrylic acid ester copolymer), more preferably contains at least one selected from ethylene / (meth)acrylate copolymer, ethylene / (meth)acrylate copolymer, ethylene / (meth)acrylate copolymer, ethylene / butyl (meth)acrylate copolymer, and ethylene / (meth)acrylate 2-ethylhexyl copolymer, and even more preferably contains at least one selected from ethylene / (meth)acrylate copolymer, ethylene / (meth)acrylate copolymer, and ethylene / (meth)acrylate copolymer, and is particularly desirable to contain ethylene / methyl methacrylate copolymer and / or ethylene / ethyl acrylate copolymer. 【0032】 In embodiments of the present invention, "(B) ethylene / carboxylic acid ester copolymer" includes an ethylene / carboxylic acid ester copolymer having a content of constituent units derived from (B1) carboxylic acid ester of 2% by mass or more and less than 25% by mass, and a melt flow rate of 1 g / 10 min or more and 400 g / 10 min or less. The content of constituent units derived from carboxylic acid ester in the ethylene / carboxylic acid ester copolymer may be 3% by mass or more and 24% by mass or less, and 5% by mass or more and 24% by mass or less. 【0033】 By having a content of constituent units derived from carboxylic acid esters of component (B1) of 2% by mass or more and less than 25% by mass, the hot melt adhesive of the embodiment of the present invention can reduce stringing and improve thermal stability and heat creep resistance. 【0034】 Component (B1) preferably contains at least one selected from ethylene / (meth)methyl copolymer, ethylene / (meth)ethyl copolymer, ethylene / (meth)butyl copolymer, and ethylene / (meth)ethylhexyl copolymer, more preferably contains at least one selected from ethylene / methyl methacrylate copolymer, ethylene / butyl copolymer, and ethylene / ethyl copolymer, particularly preferably contains ethylene / methyl methacrylate copolymer and / or ethylene / butyl copolymer, and most preferably contains ethylene / methyl methacrylate copolymer. 【0035】 In the embodiment of the present invention, when component (B1) is the copolymer described above, the hot melt adhesive exhibits improved hot tack properties while reducing stringing. 【0036】 In this specification, the content of constituent units derived from the carboxylic acid ester of (B1) refers to the mass % of constituent units derived from the carboxylic acid ester relative to the total amount of the (B1) ethylene / carboxylic acid ester copolymer. (B1) Ethylene / carboxylic acid ester copolymer has a chemical structure derived from ethylene and a chemical structure derived from carboxylic acid ester. 【0037】 "Constituent units derived from carboxylic acid esters" refers to the chemical structures of (B1) ethylene / carboxylic acid ester copolymers that are derived from carboxylic acid esters. For example, an ethylene / methyl methacrylate copolymer containing 20% ​​by mass of (B1) methyl methacrylate means that 20 parts by mass of the chemical structure derived from methyl methacrylate are contained in 100 parts by mass of the (B1) ethylene / methyl methacrylate copolymer. 【0038】 In this specification, the content of constituent units derived from (B1) ethylene / carboxylic acid ester compounds is determined by infrared absorption spectroscopy using a press sheet of component (B1). For example, if the carboxylic acid ester is methyl methacrylate, the content of constituent units derived from methyl methacrylate in the ethylene / methyl methacrylate copolymer can be measured according to JIS K7192. 【0039】 For the characteristic absorption in the infrared absorption spectrum, the peak attributed to the carboxylic acid ester copolymer is used, and the absorbance is corrected by the thickness of the press sheet to determine the comonomer content. For example, if the carboxylic acid ester is methyl methacrylate, the methyl methacrylate unit content of the ethylene / methyl methacrylate copolymer can be measured by infrared absorption spectroscopy using an infrared spectrometer after preparing a press sheet with a thickness of 0.3 mm. The characteristic absorption in the infrared absorption spectrum is 3448 cm⁻¹, which is attributed to methyl methacrylate. -1 Using the peak, the absorbance is corrected for the thickness according to the following formula to determine the content. 【0040】 MMA = 4.1 × log(I0 / I) / t - 5.3 [In the formula, MMA is the content of methyl methacrylate units (mass%), and I is the frequency of 3448 cm⁻¹.] -1The transmitted light intensity at I0 is at a frequency of 3448 cm⁻¹. -1 The incident light intensity is shown, and t represents the thickness (cm) of the sample sheet being measured. 【0041】 (B1) The method for producing the ethylene / carboxylic acid ester copolymer is not particularly limited and can include known liquid-phase polymerization methods and high-pressure radical polymerization methods. As an example of a method for producing component (B1) by high-pressure radical polymerization, one example is to polymerize ethylene and a carboxylic acid ester in the presence of a radical generator, using a tank reactor or a tubular reactor, under conditions of a polymerization pressure of 140 MPa to 300 MPa and a polymerization temperature of 100°C to 300°C. Furthermore, hydrocarbons such as hydrogen, methane, and ethane can be used as molecular weight modifiers to adjust the melt flow rate. 【0042】 In embodiments of the present invention, component (B) comprises a copolymer of (B1) ethylene and a carboxylic acid ester, and the melt flow rate of component (B1) is 1 g / 10 min or more and 400 g / 10 min or less, preferably 1 g / 10 min or more and 200 g / 10 min or less, more preferably 1 g / 10 min or more and 100 g / 10 min or less, and particularly preferably 1 g / 10 min or more and 30 g / 10 min or less. 【0043】 When component (B1) is an ethylene / (meth)acrylic acid ester copolymer, the melt flow rate is preferably 1 g / 10 min or more and 40 g / 10 min or less, more preferably 1 g / 10 min or more and 30 g / 10 min or less, and particularly preferably 2 g / 10 min or more and 30 g / 10 min or less. 【0044】 When component (B1) is not an ethylene / (meth)acrylic acid ester copolymer, but rather an ethylene / vinyl carboxylate copolymer and a carboxylic acid / allyl copolymer such as an ethylene / vinyl acetate copolymer and an ethylene / allyl acetate copolymer, the melt flow rate is preferably 50 g / 10 min or more and 400 g / 10 min or less, more preferably 100 g / 10 min or more and 400 g / 10 min or less, and particularly preferably 150 g / 10 min or more and 400 g / 10 min or less. 【0045】 When the melt flow rate of component (B1) is as described above, the hot melt adhesive of the embodiment of the present invention exhibits reduced stringing and improved thermal stability. In this specification, the melt flow rate is measured in accordance with JIS K7210, using values ​​obtained at 190°C and a 2.16 kg load. 【0046】 (B1) A commercially available product can be used as the ethylene / carboxylic acid ester copolymer. For example, a commercially available product of such component (B1) is: Products manufactured by Sumitomo Chemical, such as Aclift WH401-F (product name), Aclift WH206-F (product name), Aclift WD301-F (product name), Aclift WD203-1 (product name), etc. Products manufactured by Arkema, such as Rotrill 17BA07N (product name), Rotrill 24MA02N (product name), Rotador 4503 (product name), Rotador 8200 (product name), etc. NUC-6220 (product name) and DPDJ-9169 (product name) manufactured by Dow Chemical, etc. Examples include the UltraSen 680 (product name) and UltraSen 681 (product name) manufactured by Tosoh Corporation. 【0047】 (B) The ethylene / carboxylic acid ester copolymer may contain (B2) other ethylene / carboxylic acid ester copolymers. (B2) Other ethylene / carboxylic acid ester copolymers are ethylene / carboxylic acid ester copolymers other than component (B1), and specifically, for example, ethylene / carboxylic acid ester copolymers in which the constituent units derived from carboxylic acid ester are 2% by mass or more and not less than 25% by mass (i.e., less than 2% by mass or 25% by mass or more), or in which the melt flow rate is 1 g / 10 min or more and not 400 g / 10 min or less (i.e., less than 1 g / 10 min or greater than 400 g / 10 min). 【0048】 The hot-melt adhesive of the embodiment of the present invention may contain, in addition to (A) ethylene / olefin copolymer having 3 to 20 carbon atoms and (B) ethylene / carboxylic acid ester copolymer, other ethylene-based polymers. Examples of other ethylene-based polymers include ethylene / carboxylic acid copolymers and ethylene / carboxylic acid anhydride copolymers. 【0049】 In this specification, "ethylene / carboxylic acid copolymer" means a copolymer of ethylene and a carboxylic acid having an ethylenic double bond. "Carboxylic acid having an ethylenically double bond" refers to any compound having an ethylenically double bond and a carboxyl group, and is not particularly limited as long as it can produce the hot-melt adhesive targeted by the present invention. Specifically, examples include oleic acid, linoleic acid, maleic acid, itaconic acid, succinic acid, acrylic acid, and methacrylic acid. 【0050】 Specific examples of ethylene / carboxylic acid copolymers include copolymers of ethylene and acrylic acid, and copolymers of ethylene and methacrylic acid. An "ethylene / carboxylic acid anhydride copolymer" refers to a copolymer of ethylene and a carboxylic acid anhydride that has an ethylenic double bond. 【0051】 A "carboxylic acid anhydride having an ethylenically double bond" is a compound having a carboxylic acid anhydride group formed by the dehydration condensation of two carboxyl groups, and is not particularly limited as long as it can produce the hot-melt adhesive targeted by the present invention. Specifically, examples include maleic anhydride. A specific example of an ethylene / carboxylic acid anhydride copolymer is a copolymer of ethylene and maleic anhydride. 【0052】 (C) Wax In embodiments of the present invention, (C) wax refers to an organic substance with a weight-average molecular weight of less than 10,000 that is solid at room temperature and becomes liquid when heated, and is generally referred to as "wax." It is not particularly limited as long as it has wax-like properties and can produce the hot-melt adhesive targeted by the present invention. The hot melt adhesive of the embodiment of the present invention, by containing (C) wax, exhibits superior adhesion, hot tack, and stringing properties in high-temperature regions. 【0053】 (C) Examples of waxes include Fischer-Tropsch wax, paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, etc. Commercially available waxes can be used, and waxes can be used alone or in combination. 【0054】 In this specification, (C) wax preferably includes Fischer-Tropsch wax. "Fischer-Tropsch wax" refers to a wax synthesized by the Fischer-Tropsch process and generally known as Fischer-Tropsch wax. Fischer-Tropsch wax is obtained by separating a wax from a wax whose component molecules have a relatively broad carbon number distribution so that the component molecules have a narrow carbon number distribution. Representative Fischer-Tropsch waxes include Sazole H1 (trade name), Sazole C105, and Sazole C80 (trade name), all of which are commercially available from Sazole Wax. When the hot-melt adhesive of the embodiment of the present invention contains Fischer-Tropsch wax, it exhibits superior thermal stability and, moreover, superior adhesion in high-temperature regions. 【0055】 (C) The melting point of the wax may be, for example, 60 to 160°C or 65 to 150°C. The melting point of Fischer-Tropsch wax is preferably 70 to 120°C. The melting point of the wax is the value measured using differential scanning calorimetry (DSC). Specifically, using a DSC6220 (trade name) manufactured by SII Nanotechnology, 10 mg of the sample is weighed into an aluminum container, and the temperature at the peak of the melting is measured at a heating rate of 10°C / min, and the temperature at the peak of the melting is defined as the melting point. (C) When the melting point of the wax is within the above range, the hot melt adhesive of the embodiment of the present invention is superior in terms of adhesion, hot tack, and stringing properties in the high-temperature range. 【0056】 <(D) Tackifying resin> The hot melt adhesive of the embodiment of the present invention preferably contains (D) a tackifying resin in addition to components (A), (B), and (C). When the hot melt adhesive of the embodiment of the present invention contains (D) a tackifying resin, its low-temperature adhesion is significantly improved and its hot tack properties are superior. (D) The tackifying resin is not particularly limited as long as it is commonly used in hot melt adhesives and can produce the hot melt adhesive for which the present invention is intended. Considering the hot melt adhesive for which the present invention is intended, it is preferable to include both (D1) a partially hydrogenated tackifying resin and (D2) a fully hydrogenated tackifying resin. 【0057】 In this specification, (D1) a partially hydrogenated tackifying resin is a tackifying resin in which hydrogen is added to some of the double bonds in the tackifying resin, and (D2) a fully hydrogenated tackifying resin is a tackifying resin in which hydrogen is added to all of the double bonds in the tackifying resin. (D1) Partially hydrogenated tackifier resin has good compatibility with (B) ethylene / carboxylic acid ester copolymer, and (D2) fully hydrogenated tackifier resin has good compatibility with (A) ethylene / olefin copolymer with 3 to 20 carbon atoms. In other words, when (D) tackifier resin contains both components (D1) and (D2), the overall compatibility of the hot melt adhesive is improved, and as a result, the thermal stability is significantly improved. 【0058】 (D) Examples of tackifying resins include natural rosin, modified rosin, hydrogenated rosin, glycerol ester of natural rosin, glycerol ester of modified rosin, pentaerythritol ester of natural rosin, pentaerythritol ester of modified rosin, pentaerythritol ester of hydrogenated rosin, copolymer of natural terpenes, three-dimensional polymer of natural terpenes, hydrogenated derivatives of hydrogenated terpene copolymers, polyterpene resins, hydrogenated derivatives of phenolic modified terpene resins, aliphatic petroleum hydrocarbon resins, hydrogenated derivatives of aliphatic petroleum hydrocarbon resins, aromatic petroleum hydrocarbon resins, hydrogenated derivatives of aromatic petroleum hydrocarbon resins, cyclic aliphatic petroleum hydrocarbon resins, and hydrogenated derivatives of cyclic aliphatic petroleum hydrocarbon resins. These tackifying resins can be used alone or in combination. Liquid tackifying resins can also be used, provided they are colorless to pale yellow, substantially odorless, and have good thermal stability. 【0059】 (D) The tackifying resin preferably contains both a hydrocarbon resin with a softening point of less than 120°C and a hydrocarbon resin with a softening point of 120°C or higher. When the hot melt adhesive of the embodiment of the present invention contains both a hydrocarbon resin with a softening point of less than 120°C and a hydrocarbon resin with a softening point of 120°C or higher, the adhesion can be further improved while stringing can be further reduced, and the thermal stability can be further improved. The softening point of the tackifying resin (D) is measured in accordance with JIS K2207. 【0060】 (D) Commercially available products can be used as the tackifying resin. Examples of such commercially available products include T-REZ HC103 (product name), T-REZ HA103 (product name), and T-REZ HA125 (product name) from ENEOS Corporation, ECR5600 (product name) from ExxonMobil Corporation, Maruka Clear H (product name) from Maruzen Petrochemical Co., Ltd., Clearon K100 (product name) from Yasuhara Chemical Co., Ltd., Alcon M100 (product name) from Arakawa Chemical Co., Ltd., iMarb S100 (product name), iMarb Y135 (product name), and iMarb P125 (product name) from Idemitsu Petrochemical Co., Ltd., Clearon K4090 (product name) and Clearon K4100 from Yasuhara Chemical Co., Ltd., ECR231C (product name), ECR179EX (product name) from ExxonMobil Corporation, and Rigalight R7100 (product name) from Eastman Chemical Corporation. These commercially available tackifying resins can be used individually or in combination. 【0061】 (D1) As a partially hydrogenated tackifying resin, commercially available products can be used. Preferred commercially available products include, for example, T-REZ HC103 (product name) manufactured by ENEOS Corporation and Alcon M100 (product name) manufactured by Arakawa Chemical Corporation. (D2) As a fully hydrogenated tackifying resin, preferred products include, for example, T-REZ HA103 (product name), T-REZ HA125 (product name), and iMarb P125 (product name) manufactured by Idemitsu Petrochemical Corporation. 【0062】 In embodiments of the present invention, (A1) metallocene-based ethylene / propylene copolymer is preferably present in 5 to 60 parts by mass, particularly preferably 5 to 30 parts by mass, and most preferably 5 to 25 parts by mass, per 100 parts by mass of the total of (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) ethylene / carboxylic acid ester copolymer, and (C) wax. 【0063】 The hot melt adhesive of the embodiment of the present invention, when the content of (A1) metallocene-based ethylene / propylene copolymer is within the range described above, exhibits superior thermal stability, significantly improved hot tack and heat creep resistance, and a high level of improved low-temperature adhesion. 【0064】 In embodiments of the present invention, (B1) ethylene / carboxylic acid ester copolymer is preferably present in 4 to 20 parts by mass per 100 parts by mass of the total of (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) ethylene / carboxylic acid ester copolymer, and (C) wax, particularly preferably in 5 to 15 parts by mass, and most preferably in 5 to 12 parts by mass. In the embodiments of the present invention, when the content of (B1) ethylene / carboxylic acid ester copolymer is within the range described above, the hot melt adhesive exhibits reduced stringing and improved thermal stability and heat creep resistance to a high degree. 【0065】 In embodiments of the present invention, the amount of (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) ethylene / carboxylic acid ester copolymer, and (C) wax is preferably 20 to 60 parts by mass, particularly preferably 30 to 55 parts by mass, and most preferably 30 to 45 parts by mass, per 100 parts by mass of the total of (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) ethylene / carboxylic acid ester copolymer, and (C) wax. The hot melt adhesive of the embodiment of the present invention is superior in thermal stability and adhesive strength in the high-temperature range when the content of (C) wax is within the range described above. 【0066】 In embodiments of the present invention, (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) ethylene / carboxylic acid ester copolymer, and (C) wax are preferably present in amounts of 40 to 110 parts by mass, particularly preferably 40 to 110 parts by mass, and most preferably 55 to 90 parts by mass. In the embodiment of the present invention, when the content of (D) the tackifying resin is within the range described above, the hot melt adhesive exhibits improved low-temperature adhesion and hot tack properties at a high level. 【0067】 The hot melt adhesive of the embodiment of the present invention preferably contains (A) an ethylene / C3-C20 olefin copolymer which includes both (A1) a metallocene-based propylene / ethylene copolymer and (A2) a metallocene-based ethylene / octene copolymer, (B) an ethylene / carboxylic acid ester copolymer which has a content of (B1) carboxylic acid ester-derived constituent units of 2% by mass or more and less than 25% by mass, and a melt flow rate of 1 g / 10 min or more and 400 g / 10 min or less, and (C) a wax which preferably contains Fischer-Tropsch wax. 【0068】 The hot melt adhesive of the embodiment of the present invention is particularly preferably (A) an ethylene / C3-C20 olefin copolymer comprising both (A1) a metallocene-based propylene / ethylene copolymer and (A2) a maleic anhydride-modified metallocene-based ethylene / octene copolymer, (B) an ethylene / carboxylic acid ester copolymer comprising an ethylene / methyl methacrylate copolymer having a content of (B1) methyl (meth)acrylate-derived structural units of 2% by mass or more and less than 25% by mass, and a melt flow rate of 1 g / 10 min or more and 400 g / 10 min or less, (C) a wax comprising Fischer-Tropsch wax, and further comprising (D) a tackifying resin. 【0069】 The hot melt adhesive of the embodiment of the present invention most preferably contains, per 100 parts by mass of the total of (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) ethylene / carboxylic acid ester copolymer, and (C) wax, 5 to 60 parts by mass of (A1) metallocene-based propylene / ethylene copolymer, (A2) maleic anhydride-modified metallocene-based ethylene / octene copolymer, 4 to 20 parts by mass of (B1) ethylene / methyl methacrylate copolymer having a content of 2% by mass or more and less than 25% by mass of constituent units derived from methyl methacrylate, 20 to 60 parts by mass of Fischer-Tropsch wax, and (D) tackifying resin. 【0070】 The hot-melt adhesive according to embodiments of the present invention may further contain various additives as needed. Examples of such additives include plasticizers, stabilizers (ultraviolet absorbers, antioxidants), particulate fillers, and fluorescent whitening agents. 【0071】 The "plasticizer" is formulated for the purpose of reducing the melt viscosity of the hot melt adhesive, imparting flexibility, and improving wettability to the adherend. It is not particularly limited as long as it is compatible with components (A) to (C) and can produce the hot melt adhesive targeted by the present invention. Examples of plasticizers include paraffinic oils, naphthenic oils, and aromatic oils. Colorless and odorless paraffinic oils are particularly preferred. 【0072】 Commercially available plasticizers can be used. Examples include White Oil Broom 350 (trade name) from Kukdong Oil & Chem, Diana Fresia S32 (trade name), Diana Process Oil PW-90 (trade name), DN Oil KP-68 (trade name) from Idemitsu Kosan, Enerper M1930 (trade name) from BP Chemicals, Kaydol (trade name) from Crompton, and Primol 352 (trade name) from Esso. These plasticizers can be used alone or in combination. 【0073】 A "stabilizer" is a substance added to a hot melt adhesive to improve its stability by preventing molecular weight reduction, gelation, discoloration, and odor generation due to heat, air, and light. It is not particularly limited as long as it can produce the hot melt adhesive targeted by the present invention. Examples of stabilizers include antioxidants and ultraviolet absorbers. 【0074】 "Ultraviolet absorbers" are used to improve the light resistance of hot melt adhesives. "Antioxidants" are used to prevent oxidative degradation of hot melt adhesives. Antioxidants and ultraviolet absorbers are generally those used in hot melt adhesives and are not particularly limited as long as they can be used to obtain the paper products intended for the purposes described below. 【0075】 Examples of antioxidants include phenolic antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. Examples of UV absorbers include benzotriazole-based UV absorbers and benzophenone-based UV absorbers. Furthermore, lactone-based stabilizers may also be added. These can be used individually or in combination. 【0076】 Commercially available stabilizers can be used. Examples include Sumitomo Chemical Co., Ltd.'s SumiLizer GM (product name), SumiLizer TPD (product name), and SumiLizer TPS (product name); BASF's Irganox 1010 (product name), Irganox HP2225FF (product name), Irgaphos 168 (product name), and Irganox 1520 (product name); ADEKA's Adeka Stab AO-60 (product name); and Johoku Chemical Co., Ltd.'s JF77 (product name) and JP-650 (product name). These stabilizers can be used individually or in combination. 【0077】 The hot-melt adhesive according to embodiments of the present invention may further contain a particulate filler. The particulate filler can be any commonly used one, and is not particularly limited as long as it can produce the hot-melt adhesive targeted by the present invention. Examples of "particulate fillers" include mica, calcium carbonate, kaolin, talc, titanium dioxide, diatomaceous earth, urea-based resin, styrene beads, calcined clay, starch, etc. Their shape is preferably spherical, and their dimensions (diameter in the case of a sphere) are not particularly limited. One commercially available fluorescent whitening agent is Tinoparl OB (trade name) manufactured by BASF. 【0078】 The hot melt adhesive according to the embodiment of the present invention can be manufactured using a generally known method for manufacturing hot melt adhesives by blending (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) ethylene / carboxylic acid ester copolymer, and (C) wax, and optionally (D) tackifying resin and / or the various additives mentioned above. For example, the above-mentioned components can be mixed in predetermined amounts and heated to melt them for production. As long as the desired hot-melt adhesive can be obtained, the order in which each component is added, the heating method, etc., are not particularly limited. 【0079】 The method of applying hot melt adhesive is not particularly limited as long as the desired paper product can be obtained, but hot melt applicators are widely used. Examples of hot melt applicators include Nordson's ProBlue P4 melter (trade name) and ProBlue P10 melter (trade name). 【0080】 Coating methods can be broadly classified into, for example, contact coating and non-contact coating. "Contact coating" refers to a coating method in which the sprayer is in contact with the material or film when applying hot melt adhesive, while "non-contact coating" refers to a coating method in which the sprayer is not in contact with the material or film when applying hot melt adhesive. Examples of contact coating methods include slot coater coating and roll coater coating, while examples of non-contact coating methods include spiral coating which can coat in a spiral pattern, omega coating and control seam coating which can coat in a wave pattern, slot spray coating and curtain spray coating which can coat in a surface pattern, dot coating which can coat in a dot pattern, and bead coating which can coat in a linear pattern. 【0081】 When applying the hot melt adhesive according to the embodiment of the present invention using a hot melt applicator (even when the hot melt adhesive is dispensed horizontally to the ground using the hot melt applicator), almost no thread-like material of the hot melt adhesive is dispensed. Therefore, the adherend and the applicator will not be contaminated with thread-like material. 【0082】 The hot-melt adhesive according to the embodiments of the present invention can be widely used in, for example, electronic components, woodworking, building materials, sanitary materials, paper products, etc., but it can be suitably used for manufacturing paper products and is useful as a hot-melt adhesive for paper products. 【0083】 The paper products of the embodiments of the present invention refer to paper products manufactured using the hot-melt adhesive described above. The types of paper products are not particularly limited as long as they are manufactured using the hot-melt adhesive described above, but specific examples include books, calendars, corrugated cardboard, and cartons. Considering the properties of the hot-melt adhesive of the embodiments of the present invention, cardboard such as corrugated cardboard and cartons are particularly effective as paper products of the embodiments of the present invention. [Examples] 【0084】 The present invention will now be described in more detail and more specifically using examples. These examples are for illustrative purposes only and do not limit the present invention in any way. The components to be incorporated into the hot melt adhesive are shown below. 【0085】 (A) Ethylene / olefin copolymer with 3 to 20 carbon atoms (A1-1) Metallocene-based ethylene / propylene copolymer (ethylene content: 6.0% by mass, melting point: 97°C, melt viscosity at 190°C: 1200 mPa·s, manufactured by ExxonMobil as Vistamax 88880 (product name)) (A1-2) Metallocene-based ethylene / propylene copolymer (ethylene content: 7.1% by mass, melting point: 112°C, melt viscosity at 190°C: 1850 mPa·s, manufactured by ExxonMobil as Vistamax A (trade name)) (A1-3) Metallocene-based ethylene / propylene copolymer (ethylene content: 15% by mass, melting point: 45.2°C, 230°C melt flow rate: 20g / 10min, manufactured by ExxonMobil, product name: Vistamax 6202) (A'1-4) Ziegranata-type ethylene / propylene copolymer (melting point: 141°C, 190°C melt viscosity: 450 mPa·s, Lexentac 2304 (product name) manufactured by Lextac Corporation) (A'1-5) Ziegranata-type ethylene / propylene copolymer (softening point: 120°C, 190°C melt viscosity: 3300 mPa·s, Eastman Chemical Company's Aerafin 35 (trade name)) 【0086】 (A2-1) Maleic anhydride-modified metallocene ethylene / octene copolymer (1-octene content: 35-37% by mass, melt flow rate: 660 g / 10 min, Dow Chemical's Affinity GA1000R (product name)) (A2-2) Metallocene-based ethylene / octene copolymer. 1-octene content: 35-37% by mass, melt flow rate: 1000g / 10min, Dow Chemical Affinity GA1900 (product name). (A2-3) Metallocene-based ethylene / octene copolymer (1-octene content: 35-37% by mass, melt flow rate: 500g / 10min, Affinity GA1950 (product name) manufactured by Dow Chemical) (A2-4) Metallocene-based ethylene / octene copolymer. 1-octene content: 35-37% by mass, melt flow rate: 1200 g / 10 min, Dow Chemical Affinity GA1875 (product name). (A3-1) Metallocene-based ethylene / hexene copolymer (melt flow rate: 12g / 10min, Nipolon Z HM510R (product name) manufactured by Tosoh Corporation) (A3-2) Metallocene-based ethylene / hexene copolymer (melt flow rate: 8g / 10min, Excellen FX402 (product name) manufactured by Sumitomo Chemical Co., Ltd.) 【0087】 (B) Ethylene / carboxylic acid copolymer (B1) Ethylene / (meth)acrylic acid copolymer having a content of constituent units derived from (meth)acrylic acid ester of 2% by mass or more and less than 25% by mass, and a melt flow rate of 1 g / 10 min or more and 400 g / 10 min or less. (B1-1) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 20% by mass, melt flow rate: 20g / 10min, Sumitomo Chemical's Aclift WH401-F (product name)) (B1-2) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 20% by mass, melt flow rate: 2g / 10min, manufactured by Sumitomo Chemical Co., Ltd., Aclift WH206-F (product name)) (B1-3) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 5% by mass, melt flow rate: 2g / 10min, Sumitomo Chemical's Aclift WH301-F (product name)) (B1-4) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 24% by mass, melt flow rate: 2g / 10min, Lotril 24MA02N (product name) manufactured by Arkema) (B1-5) Ethylene / ethyl acrylate copolymer (ethyl acrylate content: 20% by mass, melt flow rate: 20g / 10min, DPDJ-9169 (product name) manufactured by Dow Chemical) (B1-6) Ethylene / vinyl acetate copolymer (vinyl acetate content: 20% by mass, melt flow rate: 160g / 10min, manufactured by Tosoh Corporation using UltraSen 680 (product name)) (B1-7) Ethylene / vinyl acetate copolymer (vinyl acetate content: 20% by mass, melt flow rate: 350 g / 10 min, manufactured by Tosoh Corporation as UltraCen 681 (product name)) 【0088】 (B2) Component other than (B1) ethylene / carboxylic acid ester copolymer (B2-1) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 32% by mass, melt flow rate: 450 g / 10 min, manufactured by Sumitomo Chemical Co., Ltd., product name: Aclift CM5022) (B2-2) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 28% by mass, melt flow rate: 150g / 10min, manufactured by Sumitomo Chemical Co., Ltd., product name: Aclift CM5023) (B2-3) Ethylene / butyl acrylate copolymer (butyl acrylate content: 35% by mass, melt flow rate: 320 g / 10 min, Lotril 35BA320 (product name) manufactured by Arkema) 【0089】 (C) Wax (C1-1) Fischer-Tropsch wax (melting point: 108°C, penetration: 2, manufactured by Sazol, brand name: Sazol H1) (C1-2) Fischer-Tropsch wax (melting point 112°C, penetration 2, Sazol C105 (product name) manufactured by Sazol) (C1-3) Fischer-Tropsch wax (melting point: 80°C, penetration: 2, manufactured by Sazol, brand name Sazol C80) (C2) Paraffin wax (melting point: 69°C, penetrating degree: 12, Paraffin 155F (product name) manufactured by Nippon Seiro Co., Ltd.) (C3) Microcrystalline wax (melting point: 84℃, penetrating degree: 12, manufactured by Nippon Seiro Co., Ltd. as Hi-Mic 1080 (product name)) (C4) Polyethylene wax (melting point: 109°C, penetrating degree: 7, manufactured by Mitsui Chemicals, Inc., High Wax 320P (product name)) (C5) Polypropylene wax (melting point: 140~148℃, penetrating degree: 1 or less, Mitsui Chemicals' High Wax NP105 (product name)) 【0090】 (D) Tackifying resin (D1) Partially hydrogenated tackifier resin (D1-1) Hydrogenated alicyclic / aromatic copolymer hydrocarbon resin (softening point: 103°C, ENEOS T-REZ HC103 (product name)) (D2) Fully hydrogenated tackifier resin (D2-1) Hydrogenated alicyclic hydrocarbon resin (softening point: 103°C, ENEOS T-REZ HA103 (product name)) (D2-2) Hydrogenated alicyclic hydrocarbon resin (softening point: 125°C, ENEOS T-REZ HA125 (product name)) (D2-3) Hydrogenated alicyclic hydrocarbon resin (softening point: 125°C, iMarb P125 (product name) manufactured by Idemitsu Oil Co., Ltd.) 【0091】 (E) Stabilizer (E1) Phenolic antioxidant (ADEKA AO-60 (product name) manufactured by ADEKA Corporation) (E2) Phosphorus-based antioxidant (JP650 manufactured by Johoku Chemical Co., Ltd.) (E3) Sulfur-based antioxidant (Sumirizer TPS manufactured by Sumitomo Chemical Co., Ltd.) 【0092】 The above-mentioned components were melt-mixed in the proportions (parts by mass) shown in Tables 1 to 3. Using a universal stirrer, each component was melt-mixed at approximately 145°C for approximately 1 hour to produce the hot-melt adhesives of Examples 1 to 15 and Comparative Examples 1 to 6. The hot-melt adhesives of the Examples and Comparative Examples were evaluated for their adhesiveness, thermal stability, hot tack, heat creep resistance, and stringing properties using the following methods. 【0093】 Adhesion was tested by applying hot-melt adhesive to one sheet of K-liner corrugated cardboard and bonding it to another sheet to obtain a sample. Thermal stability was tested by storing the hot-melt adhesive in a 150°C atmosphere for one week (168 hours) and checking the viscosity change rate and the formation of carbides. Setting properties were evaluated by preparing samples with various pressurization times and then performing peel tests. Stringiness was evaluated by checking the discharge state of the hot-melt adhesive under 180°C conditions. A summary of each evaluation is described below. 【0094】 The above-mentioned components were melt-mixed in the proportions (parts by mass) shown in Tables 1 to 3. Using a universal stirrer, each component was melt-mixed at approximately 145°C for approximately 1 hour to produce the hot-melt adhesives of Examples 1 to 15 and Comparative Examples 1 to 6. The hot-melt adhesives of the Examples and Comparative Examples were evaluated for their adhesiveness, thermal stability, hot tack, heat creep resistance, and stringing properties using the following methods. 【0095】 Adhesion was tested by applying hot melt adhesive to one sheet of K-liner corrugated cardboard and bonding it to another sheet of K-liner corrugated cardboard to obtain a sample. Thermal stability was assessed by storing the hot melt adhesive in a 150°C atmosphere for one week (168 hours) and checking the viscosity change rate and carbide formation. Hot tack properties and heat creep resistance were evaluated by preparing samples with varying pressurization times and then performing peel tests. The stringing properties were assessed by checking the discharge state of the hot melt adhesive under 180°C conditions. The following is a summary of each evaluation. 【0096】 <Adhesion to general cardboard> (Sample preparation) Hot melt adhesive, melted at 180°C, is applied to K-liner corrugated cardboard at a coating rate of 2g / m². After an open time of 3 seconds, a press pressure of 1kg / 25cm is applied. 2 A sample was prepared by bonding another sheet of K-liner cardboard to the first sheet of K-liner cardboard under a set time (pressure time) of 10 seconds. At least three samples were prepared for each hot melt adhesive. (Evaluation method) The prepared samples were cured for 24 hours in a constant temperature chamber set to 60°C, 23°C, or -10°C. Afterward, they were forcibly peeled off by hand under the same conditions. The material failure rate (the percentage of material that was destroyed) was defined as the percentage of the total adhesive area that was damaged, and the condition of the adhesive surface of the K-liner corrugated cardboard was evaluated. The evaluation criteria are as follows: ◎: Material failure rate is higher than 80% ○: Material failure rate is 60% or higher, and 80% or lower. △: Material failure rate is 30% or more, but less than 60%. ×: Material failure rate is less than 30% 【0097】 <Adhesion to cardboard coated with chemicals> (Sample preparation) A hot-melt adhesive, melted at 180°C, was applied to cardboard coated with varnish (difficult to bond) at a rate of 2g / m². After an open time of 3 seconds, a press pressure of 1kg / 25cm was applied. 2 A sample was prepared by bonding another sheet of K-liner cardboard to the first sheet of K-liner cardboard under a set time (pressure time) of 10 seconds. At least three samples were prepared for each hot melt adhesive. (Evaluation method) The prepared samples were cured for 24 hours in a constant temperature chamber set to 60°C, 23°C, or -10°C. Afterward, they were forcibly peeled off by hand under the same conditions. The material failure rate (the percentage of material that was destroyed) was defined as the percentage of the total adhesive area that was damaged, and the condition of the adhesive surface of the K-liner corrugated cardboard was evaluated. The evaluation criteria are as follows: ◎: Material failure rate is higher than 80% ○: Material failure rate is 60% or higher, and 80% or lower. △: Material failure rate is 30% or more, but less than 60%. ×: Material failure rate is less than 30% 【0098】 <Thermal stability> (Sample preparation) Samples were prepared by placing 50g of each hot melt adhesive into 100cc glass bottles and storing them in a 150°C constant temperature bath for 168 hours. (Evaluation method) Samples of hot-melt adhesive obtained by storing them in a 150°C constant temperature bath for 168 hours were visually inspected to check for the presence or absence of char formation and the separation state of the hot-melt adhesive. The evaluation criteria are as follows. Generation of carbonized material ◎: No carbides present ○: Contains a small amount of carbide △: Contains carbides, but does not pose a practical problem. ×: Contains a significant amount of carbides. Separation state ◎: No sediment present. ○: There is a small amount of sediment present. △: There is sediment present, but it does not pose a practical problem. ×: Significant sedimentation 【0099】 <Hot Tack Properties> (Sample preparation) A hot-melt adhesive melted at 180°C was applied to K-liner corrugated cardboard at a coating rate of 2 g / m². After an open time of 1 second, a press pressure of 1 kg / 25 cm was applied. 2 Samples were prepared by bonding the K-liner cardboard to another sheet of cardboard under different set times (pressure times): 0.5 seconds, 1.0 seconds, 1.5 seconds, 2.0 seconds, and 2.5 seconds. For each hot melt adhesive, at least three samples were prepared for each set time. (Evaluation method) Immediately after the pressurization of the prepared sample, it was forcibly peeled vertically at a constant speed. The set time (pressurization time) until the K-liner corrugated cardboard was completely destroyed was defined as the hot tack time, and this time was measured. ◎: Hot tack time less than 1.5 seconds ○: Hot tack is 1.5 seconds or more, but less than 2.0 seconds. △: Hot tack is 2.0 seconds or more, but less than 2.5 seconds. ×: Hot tack lasts 2.5 seconds or longer 【0100】 <Heat-resistant creep> Hot melt adhesive, melted at 180°C, is applied to K-liner corrugated cardboard at a coating rate of 2g / m². After an open time of 3 seconds, a press pressure of 1kg / 25cm is applied. 2 A sample was prepared by bonding another sheet of K-liner cardboard to the first sheet of K-liner cardboard under a set time (pressure time) of 10 seconds. At least three samples were prepared for each hot melt adhesive. (Evaluation method) A weight was applied to one side of the K-liner cardboard sample, and the heat creep resistance was evaluated by the temperature at which the weight fell from the sample. Specifically, under a 40°C atmosphere, the sample was 25 cm long. 2 A 3kg weight was suspended vertically from one side of the K-liner cardboard sample (5cm x 5cm), and the temperature was increased by 5°C every 15 minutes to determine the temperature at which the weight would fall. ◎: The temperature at which the weight falls is 55℃ or higher. ○: The temperature at which the weight falls is 50°C or higher, but less than 55°C. △: The temperature at which the weight falls is between 45°C and 50°C. ×: The drop temperature of the weight is less than 45°C. 【0101】 <Reduced stringing> Hot melt adhesive was applied intermittently and vertically to a substrate 20 cm away from the tip of a hot melt gun. The state of the falling material between the hot melt gun and the substrate was visually observed, and the stringing properties were evaluated. (Measurement conditions) Temperature setting: Tank, hose, and nozzle all at 180°C Nozzle diameter: 14 / 1000 inches Nozzle: 4 orifice (Number of discharge ports: 4) Dispensing pressure: 0.3 MPa Application rate: 180 shots per minute for each of the four orifices. The evaluation criteria are as follows: ◎: The shape of the fallen object is granular. ○: The fallen objects are mostly granular in shape, but a small amount of thread-like material is mixed in. △: The fallen objects consist of a mixture of granular and thread-like shapes. ×: The shape of the falling object is thread-like. 【0102】 [Table 1] 【0103】 [Table 2] 【0104】 [Table 3] 【0105】 As shown in Tables 1-2, the hot melt adhesives of Examples 1-15 exhibited excellent performance in terms of adhesion, thermal stability, hot tack, heat creep resistance, and string reduction, confirming their suitability for paper processing applications such as corrugated cardboard bonding. In contrast, the hot melt adhesives of Comparative Examples 1 to 6, as shown in Table 3, do not contain any of components (A1), (B1), or (C), and therefore have an "X" in at least one of the following categories: adhesion, thermal stability, hot tack, heat creep resistance, and string reduction. [Industrial applicability] 【0106】 The present invention can provide a hot-melt adhesive and a paper product coated with the hot-melt adhesive. The paper product according to the embodiment of the present invention is particularly effective when manufactured from cardboard such as corrugated cardboard or cartons.

Claims

[Claim 1] (A) Ethylene / olefin copolymer with 3 to 20 carbon atoms, (B) Ethylene / (meth)acrylic acid ester copolymer, (C) wax, (A) Ethylene / olefin copolymer with 3 to 20 carbon atoms, (A1) metallocene-based ethylene / propylene copolymer, (B) The ethylene / (meth)acrylic acid ester copolymer contains an ethylene / (meth)acrylic acid ester copolymer having a content of (B1) (meth)acrylic acid ester-derived constituent units of 2% by mass or more and less than 25% by mass, and a melt flow rate of 1 g / 10 min or more and 40 g / 10 min or less. A hot melt adhesive comprising (A) ethylene / olefin copolymer with 3 to 20 carbon atoms, (B) ethylene / (meth)acrylic acid ester copolymer, and (C) wax, per 100 parts by mass of the total, wherein (A1) metallocene-based ethylene / propylene copolymer is present in 5 to 60 parts by mass, (B1) ethylene / (meth)acrylic acid ester copolymer is present in 3 to 20 parts by mass, and (C) wax is present in 20 to 60 parts by mass. [Claim 2] The hot melt adhesive according to claim 1, wherein (A) ethylene / olefin copolymer having 3 to 20 carbon atoms comprises (A2) metallocene ethylene / octene copolymer. [Claim 3] (A2) The hot melt adhesive according to claim 2, wherein the metallocene ethylene / octene copolymer comprises a metallocene ethylene / octene copolymer modified with a carboxylic acid and / or carboxylic acid anhydride. [Claim 4] A paper product having a hot melt adhesive according to any one of claims 1 to 3.

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