Hot melt adhesive

Abstract

To provide a hot melt adhesive that can reduce stringing and has excellent thermal stability, excellent adhesion to paper and a short set time.SOLUTION: Disclosed is 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 tackifying resin, wherein the (B) ethylene-carboxylic acid ester copolymer comprises (B1) an ethylene-(meth)acrylic acid ester copolymer containing a structural unit derived from the (meth)acrylic acid ester in an amount of 2 to 24 mass%.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 being 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 coating it on an adherend and cooling it, it solidifies to exhibit adhesiveness. Therefore, it has the characteristics of being capable of instant adhesion and high-speed adhesion, and is used in a wide range of fields such as paper processing, woodworking, sanitary materials, and the electronic field.

[0003] As the base polymer of the above hot melt adhesive, depending on its use, for example, ethylene-based copolymers such as ethylene-vinyl acetate copolymer (hereinafter also referred to as "EVA") and ethylene-ethyl acrylate copolymer (hereinafter also referred to as "EEA"), polyethylene, polypropylene, olefin resins such as amorphous polyalphaolefin (hereinafter also referred to as "APAO"), synthetic rubbers such as styrene-based block copolymers (for example, styrene-isoprene-styrene-based block copolymer (hereinafter also referred to as "SIS"), styrene-butadiene-styrene-based block copolymer (hereinafter also referred to as "SBS") and their hydrogenated products, and polyurethanes are widely used.

[0004] Among these hot melt adhesives, hot melt adhesives based on ethylene-based copolymers as the base polymer are often used in the paper processing field and the woodworking field such as bookbinding and packaging. 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 the 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 be generated between the tip of the nozzle and the adherend. This filamentous material is caused by the drawability of the hot melt adhesive and stains the nozzle and the adherend. Therefore, the development of a hot melt adhesive with less draw is an important task for adhesive manufacturers.

[0005] Patent Documents 1 to 3 disclose a hot melt adhesive containing an ethylene copolymer for the purpose of reducing draw. The hot melt adhesive of Patent Document 1 has an ethylene / α-olefin copolymer and an ethylene carboxylic acid ester copolymer (see [Claim 1]

[0046] to

[0056] ). The problem of filament generation is reduced by the hot melt adhesive of Patent Document 1. However, the thermal stability of the hot melt adhesive of Patent Document 1 is not sufficient, and further improvement in thermal stability is required.

[0006] Patent Document 2 discloses a hot melt adhesive containing an ethylene-α-olefin copolymer, a functionalized ethylene-α-olefin copolymer, and an ethylene-(meth)acrylate copolymer (see [Claim 1]

[0053] to

[0067] ). The hot melt adhesive of Patent Document 2 can reduce draw to some extent, but its thermal stability cannot be said to be sufficient. The hot melt adhesive of Patent Document 3 also contains a functionalized ethylene-α-olefin copolymer and an ethylene-(meth)acrylate copolymer, similar to Patent Document 2 (see

[0063] to

[0066] ), and its thermal stability cannot be said to be excellent.

[0007] In recent years, user demands for reducing stringing in hot melt adhesives have been increasing year by year. The hot melt adhesives of Patent Documents 1 to 3 cannot fully meet the high performance requirements of users in terms of reducing stringing and thermal stability. Naturally, hot melt adhesives are excellent in adhesiveness to adherends such as paper. In recent years, further, it is required that they cure in a short time after being applied to the adherend, that is, the set time is short. When a hot melt adhesive with a long set time is applied to an adherend, it takes time for the adhesive to solidify, resulting in a decrease in the productivity of the product.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] An object of the present invention is to provide a hot melt adhesive that can reduce stringing, has excellent thermal stability, excellent adhesiveness to paper, and a short set time.

Means for Solving the Problems

[0010] As a result of intensive studies, the present inventors have found that a hot melt adhesive containing (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, and (C) a tackifying resin can solve the above problems when the content of specific structural units in the (B) ethylene / carboxylic acid ester copolymer is in a specific range, and such a hot melt adhesive is suitable for the paper processing field and the woodworking field, etc., and have completed the present invention.

[0011] This specification includes the following embodiments. 1. (A) An ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, and (C) a tackifier resin, (B) The ethylene / carboxylic acid ester copolymer is a hot melt adhesive containing an ethylene / (meth)acrylic acid ester copolymer in which the content of structural units derived from (B1) (meth)acrylic acid ester is 2 to 24% by mass. 2. The hot melt adhesive according to 1, wherein (B1) the ethylene / (meth)acrylic acid ester copolymer contains at least one selected from an ethylene / methyl methacrylate copolymer, an ethylene / butyl acrylate copolymer, and an ethylene / ethyl acrylate. 3. The hot melt adhesive according to 1 or 2, wherein (C) the tackifier resin contains (C1) a partially hydrogenated tackifier resin and (C2) a fully hydrogenated tackifier resin. 4. The hot melt adhesive according to any one of 1 to 3, wherein (C) the tackifier resin contains a hydrocarbon resin having a softening point of less than 120°C and a hydrocarbon resin having a softening point of 120°C or higher. 5. The hot melt adhesive according to any one of 1 to 4, wherein the melt flow rate of (B1) the ethylene / (meth)acrylic acid ester copolymer is 1 to 35 g / 10 min. 6. The hot melt adhesive according to any one of 1 to 5, wherein the content of (B1) is 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of components (A) to (C). 7. A paper product having the hot melt adhesive according to any one of 1 to 6.

Advantages of the Invention

[0012] The hot melt adhesive of the embodiment of the present invention can reduce stringing, is excellent in thermal stability and adhesiveness to paper, further has a short setting time, and can contribute to improving the productivity of products. When applying the hot-melt adhesive according to an embodiment of the present invention from a nozzle to an adherend such as paper, the nozzle and the adherend are not soiled by filaments. Even when the hot-melt adhesive is stored in a storage tank for a long period of time, carbides and precipitates do not occur, an increase in viscosity is suppressed, and the coating operation is not adversely affected.

Mode for Carrying Out the Invention

[0013] The hot-melt adhesive according to an 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 tackifying resin. In the present specification, the “hot-melt adhesive” is a solid at normal temperature, but has fluidity by heating and melting, and can be applied to an object such as a base material or an adherend, and cures and adheres by cooling. It refers to an adhesive.

[0014] <(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 aimed at by the present invention can be obtained. 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, more preferably propylene, butene, hexene, and octene, still more preferably propylene, butene, and octene, and particularly preferably octene.

[0015] (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), thereby becoming hard and less likely to generate stringiness.

[0016] Examples of the (A) ethylene / olefin copolymer having 3 to 20 carbon atoms include a copolymer of ethylene and octene (ethylene / octene copolymer), a copolymer of ethylene, propylene, and 1-butene (ethylene / propylene / butene copolymer), a copolymer of ethylene and propylene (ethylene / propylene copolymer), a copolymer of ethylene and butene (ethylene / butene copolymer), a copolymer of ethylene and hexene (ethylene / hexene copolymer), and the like. In particular, the (A) ethylene / olefin copolymer having 3 to 20 carbon atoms preferably contains a copolymer of ethylene and octene, a copolymer of ethylene and propylene, a copolymer of ethylene and butene, or a copolymer of ethylene and hexene, and more preferably contains a copolymer of ethylene and octene. As the (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, commercially available products can be used.

[0017] Examples of the ethylene / octene copolymer 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), Engage 8400 (trade name), etc. manufactured by The Dow Chemical Company. Examples of the ethylene / propylene / 1-butene copolymer include Vestoplast 730 (trade name), Vestoplast 708 (trade name), etc. manufactured by Evonik Degussa GmbH. Examples of the ethylene / propylene copolymer include, for example, Eastoflex E1016PL-1 manufactured by Eastman Chemical Company, the Vistamax (trade name) series manufactured by ExxonMobil Corporation, and the like.

[0018] Examples of the ethylene / butene copolymer include, for example, Toughmer A4085 manufactured by Mitsui Chemicals, Inc. Examples of the ethylene / hexene copolymer include, for example, Nipolon Z HM510R manufactured by Tosoh Corporation. Such copolymers of ethylene and olefins having 3 to 20 carbon atoms can be used alone or in combination. In the present invention, considering the reduction of yarn draw, as the (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, an ethylene / octene copolymer is preferable.

[0019] <(B) Ethylene / carboxylic acid ester copolymer> In the embodiments of the present invention, the “(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 the hot melt adhesive targeted by the present invention can be obtained.

[0020] In this specification, examples of the “carboxylic acid ester 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, vinyl carboxylates such as vinyl acetate and allyl acetate, and allyl esters. In this specification, the (meth)acrylic acid ester represents both acrylic acid esters and methacrylic acid esters.

[0021] In the 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, more preferably includes methyl (meth)acrylate, ethyl (meth)acrylate, or butyl (meth)acrylate, and particularly preferably includes methyl methacrylate and / or ethyl acrylate.

[0022] Examples of the "(B) ethylene / carboxylic acid ester copolymer" include copolymers of ethylene and (meth)acrylic acid esters (ethylene / (meth)acrylic acid ester copolymers), copolymers of ethylene and vinyl carboxylates (ethylene / vinyl carboxylate copolymers), and copolymers of ethylene and allyl carboxylates (ethylene / allyl carboxylate copolymers).

[0023] (B) The ethylene / carboxylic acid ester copolymer preferably includes a copolymer of ethylene and (meth)acrylic acid esters (ethylene / (meth)acrylic acid ester copolymer), more preferably includes at least one selected from ethylene / (meth)acrylic acid methyl copolymer, ethylene / (meth)acrylic acid ethyl copolymer, ethylene / (meth)acrylic acid butyl copolymer, and ethylene / (meth)acrylic acid 2-ethylhexyl copolymer, still more preferably includes at least one selected from ethylene / (meth)acrylic acid methyl copolymer, ethylene / (meth)acrylic acid ethyl copolymer, and ethylene / (meth)acrylic acid butyl copolymer, and particularly preferably includes ethylene / methyl methacrylate copolymer and / or ethylene / ethyl acrylate copolymer.

[0024] In an embodiment of the present invention, the “(B) ethylene / carboxylic acid ester copolymer” includes an ethylene / (meth)acrylic acid ester copolymer having a content of structural units derived from (B1) (meth)acrylic acid ester of 2 to 24% by mass. The content of the structural units derived from the (meth)acrylic acid ester in the ethylene / (meth)acrylic acid ester copolymer may be 3 to 24% by mass, or may be 5% to 24% by mass. When the content of the structural units derived from the (meth)acrylic acid ester of the component (B1) is 2 to 24% by mass, the hot melt adhesive of the embodiment of the present invention has significantly improved thermal stability.

[0025] The component (B1) preferably includes at least one selected from an ethylene / (meth)methyl acrylate copolymer, an ethylene / (meth)ethyl acrylate copolymer, an ethylene / (meth)butyl acrylate copolymer, and an ethylene / (meth)2-ethylhexyl acrylate copolymer. More preferably, it includes at least one selected from an ethylene / methyl methacrylate copolymer, an ethylene / butyl acrylate copolymer, and ethylene / ethyl acrylate. Particularly preferably, it includes an ethylene / methyl methacrylate copolymer and / or an ethylene / butyl acrylate copolymer, and most desirably, it includes an ethylene / methyl methacrylate copolymer. When the component (B1) of the hot melt adhesive of the embodiment of the present invention is the above polymer, it has better thermal stability while reducing stringiness.

[0026] The hot melt adhesive of the embodiment of the present invention can further reduce stringiness by including the (B1) ethylene / (meth)acrylic acid ester copolymer, and can maintain excellent thermal stability, excellent adhesiveness to paper, and obtain a short setting time.

[0027] In this specification, the content of the structural units derived from the (meth)acrylic acid ester of (B1) refers to the mass % of the structural units derived from the (meth)acrylic acid ester with respect to the total amount of the (B1) ethylene / (meth)acrylic acid ester copolymer. (B1) The ethylene / (meth)acrylate copolymer has a chemical structure derived from ethylene and a chemical structure derived from (meth)acrylate. The "structural unit derived from (meth)acrylate" refers to the chemical structure derived from (meth)acrylate among the chemical structures of the (B1) ethylene / (meth)acrylate copolymer. For example, an ethylene / methyl methacrylate copolymer with a methyl methacrylate content of 20% by mass means that 20 parts by mass of the chemical structure derived from methyl methacrylate is contained in 100 parts by mass of the (B1) ethylene / methyl methacrylate copolymer.

[0028] In this specification, the content of the structural unit derived from the (B1) ethylene / (meth)acrylate compound is determined by infrared absorption spectroscopy using the press sheet of component (B1). For example, when the (meth)acrylate is methyl methacrylate, the content of the structural unit derived from methyl methacrylate in the ethylene / methyl methacrylate copolymer can be measured according to JIS K7192. As the characteristic absorption of the infrared absorption spectrum, a peak attributed to the (meth)acrylate copolymer is used, and the absorbance is corrected by the press sheet thickness to determine the comonomer content. For example, when the (meth)acrylate is methyl methacrylate, the content of the methyl methacrylate unit in 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. As the characteristic absorption of the infrared absorption spectrum, the peak at 3448 cm -1 is used, and according to the following formula, the absorbance is corrected by the thickness to determine the content. MMA = 4.1×log(I0 / I) / t - 5.3 〔In the formula, MMA is the content (% by mass) of the methyl methacrylate unit, I is the transmitted light intensity at a frequency of 3448 cm-1, and I0 is the frequency of 3448 cm -1The incident light intensity at [specific condition], and t represents the thickness (cm) of the measurement sample sheet.

[0029] (B1) The method for producing the ethylene / (meth)acrylate copolymer is not particularly limited, and known liquid-phase polymerization methods, high-pressure radical polymerization methods, etc. can be mentioned. As a method for producing component (B1) by the high-pressure radical polymerization method, for example, generally using a tank-type reactor or a tubular reactor, in the presence of a radical generator, under the conditions of a polymerization pressure of 140 MPa or more and 300 MPa or less, and a polymerization temperature of 100 °C or more and 300 °C or less, a method of polymerizing ethylene and (meth)acrylate can be mentioned. Also, in order to adjust the melt flow rate, hydrocarbons such as hydrogen, methane, and ethane can be used as a molecular weight regulator.

[0030] (B1) Considering the thread drawing of the hot melt adhesive, the melt flow rate of the ethylene / (meth)acrylate copolymer is preferably 1 to 35 g / 10 min. In addition, this melt flow rate uses the value measured at 190 °C and a load of 2.16 kg measured in accordance with JIS K7210.

[0031] (B1) As the ethylene / (meth)acrylate copolymer, commercially available products can be used. Examples of such commercially available products of component (B1) include Acrifto WH401-F (trade name), Acrifto WH206-F (trade name), Acrifto WD301-F (trade name), Acrifto WD203-1 (trade name), etc. manufactured by Sumitomo Chemical Co., Ltd.; Rotril 17BA07N (trade name), Rotril 24MA02N (trade name), Rotadar 4503 (trade name), Rotadar 8200 (trade name), etc. manufactured by Arkema; NUC-6220 (trade name) manufactured by Dow Chemical; DPDJ-9169 (trade name) manufactured by Dow Chemical, etc.

[0032] (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). Specifically, for example, ethylene / (meth)acrylic acid ester copolymers in which the constituent units derived from (meth)acrylic acid ester are not 2 to 24% by mass (i.e., less than 2% by mass or more than 24% by mass); copolymers of ethylene and carboxylic acids having ethylenic double bonds other than (meth)acrylic acid esters (e.g., oleic acid, linoleic acid, maleic acid, itaconic acid, succinic acid, etc.) (e.g., ethylene / itaconic acid ester copolymer, etc.); copolymers of ethylene and vinyl carboxylates (e.g., vinyl acetate) (ethylene / vinyl carboxylate copolymers, e.g., ethylene / vinyl acetate copolymer); copolymers of ethylene and allyl carboxylates (e.g., allyl acetate) (ethylene / allyl carboxylate copolymers, e.g., ethylene / allyl acetate copolymer), etc. can be mentioned.

[0033] The hot melt adhesive of the embodiment of the present invention may contain other ethylene-based polymers in addition to (A) ethylene / olefin copolymer having 3 to 20 carbon atoms and (B) ethylene / carboxylic acid ester copolymer. Examples of other ethylene-based polymers include ethylene / carboxylic acid copolymers, ethylene / carboxylic anhydride copolymers, etc.

[0034] In this specification, the "ethylene / carboxylic acid copolymer" refers to a copolymer of ethylene and a carboxylic acid having an ethylenic double bond. The "carboxylic acid having an ethylenic double bond" is a compound having an ethylenic double bond and a carboxyl group, and is not particularly limited as long as the hot melt adhesive aimed at by the present invention can be obtained. Specifically, for example, oleic acid, linoleic acid, maleic acid, itaconic acid, succinic acid, acrylic acid, methacrylic acid, etc. can be exemplified. Specific examples of the ethylene / carboxylic acid copolymer include copolymers of ethylene and acrylic acid, and copolymers of ethylene and methacrylic acid.

[0035] The "ethylene / carboxylic anhydride copolymer" refers to a copolymer of ethylene and a carboxylic anhydride having an ethylenic double bond. The "carboxylic anhydride having an ethylenic double bond" is a compound having a carboxylic anhydride group formed by dehydration condensation of two carboxyl groups, and is not particularly limited as long as the hot melt adhesive targeted by the present invention can be obtained. Specifically, for example, maleic anhydride can be exemplified. Specific examples of the ethylene / carboxylic anhydride copolymer include a copolymer of ethylene and maleic anhydride.

[0036] <(C) Tackifying resin> (C) The tackifying resin is usually used in the hot melt adhesive and is not particularly limited as long as the hot melt adhesive targeted by the present invention can be obtained. Considering the hot melt adhesive targeted by the present invention, it is preferable to include both (C1) a partially hydrogenated tackifying resin and (C2) a fully hydrogenated tackifying resin. In the present specification, (C1) the partially hydrogenated tackifying resin is a tackifying resin in which hydrogen is added to a part of the double bonds in the tackifier, and (C2) the fully hydrogenated tackifying resin is a tackifying resin in which hydrogen is added to all of the double bonds in the tackifier. (C1) The partially hydrogenated tackifying resin has good compatibility with (B) the ethylene / carboxylic acid ester copolymer, and (C2) the fully hydrogenated tackifying resin has good compatibility with (A) the ethylene / olefin copolymer having 3 to 20 carbon atoms. That is, when the (C) tackifying resin contains both components (C1) and (C2), the compatibility of the hot melt adhesive is improved, and as a result, the thermal stability is significantly improved.

[0037] (C) Examples of the tackifier resins include natural rosin, modified rosin, hydrogenated rosin, glycerol esters of natural rosin, glycerol esters of modified rosin, pentaerythritol esters of natural rosin, pentaerythritol esters of modified rosin, pentaerythritol esters of hydrogenated rosin, copolymers of natural terpenes, three-dimensional polymers of natural terpenes, hydrogenated derivatives of copolymers of hydrogenated terpenes, polyterpene resins, hydrogenated derivatives of phenol-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, cycloaliphatic petroleum hydrocarbon resins, and hydrogenated derivatives of cycloaliphatic petroleum hydrocarbon resins. These tackifier resins can be used alone or in combination. As long as the tackifier resin has a color tone ranging from colorless to light yellow, is substantially odorless, and has good thermal stability, a liquid-type tackifier resin can also be used.

[0038] (C) The tackifier resin preferably contains both a hydrocarbon resin having a softening point of less than 120°C and a hydrocarbon resin having a softening point of 120°C or higher. The hot melt adhesive according to the embodiment of the present invention has both a hydrocarbon resin having a softening point of less than 120°C and a hydrocarbon resin having a softening point of 120°C or higher, so that the adhesiveness can be further improved while reducing the stringiness, and the thermal stability can be further enhanced. Incidentally, the softening point of the (C) tackifier resin is measured according to JIS K2207.

[0039] (C) As the tackifying resin, commercially available products can be used. Examples of such commercially available products include T-REZ HC103 (trade name), T-REZ HA103 (trade name), T-REZ HA125 (trade name) manufactured byENEOS Corporation, ECR5600 (trade name) manufactured by ExxonMobil Corporation, Marclear H (trade name) manufactured by Maruzen Petrochemical Co., Ltd., Clearon K100 (trade name) manufactured by Yasuhara Chemical Co., Ltd., Alcon M100 (trade name) manufactured by Arakawa Chemical Industries, Ltd., Imerv S100 (trade name), Imerv Y135 (trade name), Imerv P125 (trade name) manufactured by Idemitsu Petrochemical Co., Ltd., Clearon K4090 (trade name) and Clearon K4100 manufactured by Yawara Chemical Co., Ltd., ECR231C (trade name), ECR179EX (trade name) manufactured by ExxonMobil Corporation, and Rigelite R7100 (trade name) manufactured by Eastman Chemical Company. These commercially available tackifying resins can be used alone or in combination.

[0040] (C1) As the partially hydrogenated tackifying resin, commercially available products can be used. Examples of such commercially available products include T-REZ HC103 (trade name) manufactured by ENEOS Corporation and Alcon M100 (trade name) manufactured by Arakawa Chemical Industries, Ltd., which are preferred. (C2) As the fully hydrogenated tackifying resin, for example, T-REZ HA103 (trade name), T-REZ HA125 (trade name), and Imerv P125 (trade name) manufactured by Idemitsu Petrochemical Co., Ltd. are preferred.

[0041] In the hot melt adhesive according to the embodiment of the present invention, per 100 parts by mass in total of (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, and (C) a tackifying resin, it is preferable that (B1) the ethylene / (meth)acrylate copolymer contains 1 to 10 parts by mass, particularly preferably 2 to 8 parts by mass, and most desirably 2 to 7 parts by mass. When the content of the (B1) ethylene / (meth)acrylate copolymer is within the above range, the hot melt adhesive according to the embodiment of the present invention has less stringing, improved thermal stability and adhesion to paper at a high level, and a shorter setting time.

[0042] The hot-melt adhesive of the embodiment of the present invention contains, per 100 parts by mass in total of (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, and (C) a tackifier resin. The content of (A) the ethylene / olefin copolymer having 3 to 20 carbon atoms is preferably 25 to 60 parts by mass, particularly preferably 30 to 55 parts by mass, and most desirably 30 to 50 parts by mass. When the content of (A) the ethylene / olefin copolymer having 3 to 20 carbon atoms is within the above range, the hot-melt adhesive of the embodiment of the present invention has reduced stringiness, improved heat stability and adhesiveness to paper at a high level, and shortened setting time.

[0043] <(D) Wax> The hot-melt adhesive of the embodiment of the present invention preferably further contains (D) wax. In the present specification, "wax" refers to an organic substance that is solid at room temperature and becomes liquid when heated, and has a weight average molecular weight of less than 10,000, which is generally regarded as "wax". As long as it has wax-like properties and the hot-melt adhesive of the present invention can be obtained, it is not particularly limited.

[0044] Examples of the wax include Fischer-Tropsch wax, paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, etc. Commercially available products can be used as the wax, and the wax can be used alone or in combination.

[0045] In this specification, the (D) wax preferably includes Fischer-Tropsch wax. "Fischer-Tropsch wax" refers to wax synthesized by the Fischer-Tropsch process and generally regarded as Fischer-Tropsch wax. Fischer-Tropsch wax is obtained by fractionating wax so that the component molecules have a narrower carbon number distribution from wax having a relatively wide carbon number distribution of component molecules. As typical Fischer-Tropsch waxes, Sasol H1 (trade name), Sasol C105, and Sasol C80 (trade name) can be exemplified, all of which are commercially available from Sasol Wax Co., Ltd. The hot melt adhesive of the embodiment of the present invention is excellent in thermal stability and further in adhesive strength in a high temperature region by including Fischer-Tropsch wax.

[0046] The melting point of the wax may be, for example, 60 to 160°C, or may be 65 to 150°C. The melting point of Fischer-Tropsch wax is preferably 70 to 120°C. The melting point of the wax refers to the value measured using differential scanning calorimetry (DSC). Specifically, using DSC6220 (trade name) manufactured by SII NanoTechnology Inc., 10 mg of the sample is weighed into an aluminum container, measured at a heating rate of 10°C / min, and the temperature at the peak of the melting peak is defined as the melting point.

[0047] In the embodiment of the present invention, per 100 parts by mass in total of (A) ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) ethylene / carboxylic acid ester copolymer, (C) tackifying resin, and (D) wax, it is preferable that (B1) ethylene / (meth)acrylate copolymer is contained in an amount of 1 to 10 parts by mass, particularly preferably 2 to 10 parts by mass, and most desirably 2 to 6 parts by mass. When the content of the (B1) ethylene / (meth)acrylate copolymer in the hot melt adhesive of the embodiment of the present invention is within the above range, stringing is further reduced, and thermal stability, adhesiveness to paper, and setting properties are improved at a high level.

[0048] In an embodiment of the present invention, per 100 parts by mass in total of (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, (C) a tackifier resin, and (D) a wax, it is preferable that the content of (A) the ethylene / olefin copolymer having 3 to 20 carbon atoms is 20 to 50 parts by mass, particularly preferably 25 to 45 parts by mass, and most desirably 25 to 40 parts by mass. In the hot melt adhesive of the embodiment of the present invention, when the content of (A) the ethylene / olefin copolymer having 3 to 20 carbon atoms is within the above range, stringing is further reduced, and the thermal stability, adhesiveness to paper, and setting property are improved at a high level.

[0049] In an embodiment of the present invention, per 100 parts by mass in total of (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, (C) a tackifier resin, and (D) a wax, it is preferable that the content of (C) the tackifier resin is 30 to 60 parts by mass, particularly preferably 35 to 55 parts by mass, and most desirably 40 to 55 parts by mass. In the hot melt adhesive of the embodiment of the present invention, when the content of (C) the tackifier resin is within the above range, stringing is further reduced, and the thermal stability, adhesiveness to paper, and setting property are improved at a high level.

[0050] The hot melt adhesive of the embodiment of the present invention may further contain various additives as required. Examples of such various additives include plasticizers, stabilizers (ultraviolet absorbers, antioxidants), and particulate fillers. The "plasticizer" is blended for the purpose of reducing the melt viscosity of the hot melt adhesive, imparting flexibility, and improving wetting to the adherend. It is not particularly limited as long as it is compatible with components (A) and (B) and can obtain the hot melt adhesive targeted by the present invention. Examples of the plasticizer include paraffinic oil, naphthenic oil, and aromatic oil. Paraffinic oil that is colorless and odorless is particularly preferable.

[0051] Commercially available products can be used as plasticizers. For example, White Oil Broom350 (trade name) manufactured by Kukdong Oil&Chem, Diana Freshia S32 (trade name), Diana Process Oil PW-90 (trade name), DN Oil KP-68 (trade name) manufactured by Idemitsu Kosan Co., Ltd., Enerper M1930 (trade name) manufactured by BP Chemicals, Kaydol (trade name) manufactured by Crompton, and Primol 352 (trade name) manufactured by Esso can be exemplified. These plasticizers can be used alone or in combination.

[0052] The "stabilizer" is compounded to prevent the molecular weight reduction, gelation, coloring, odor generation, etc. of the hot melt adhesive due to heat, air, light, etc., and to improve the stability of the hot melt adhesive. It is not particularly limited as long as it can obtain the hot melt adhesive targeted by the present invention. As the stabilizer, for example, antioxidants and ultraviolet absorbers can be exemplified.

[0053] The "ultraviolet absorber" is used to improve the light resistance of the hot melt adhesive. The "antioxidant" is used to prevent the oxidative degradation of the hot melt adhesive. The antioxidant and the ultraviolet absorber are generally those used in hot melt adhesives and are not particularly limited as long as they can obtain the target paper product described later.

[0054] As the "antioxidant", for example, phenolic antioxidants, sulfur antioxidants, and phosphorus antioxidants can be exemplified. As the ultraviolet absorber, for example, benzotriazole-based ultraviolet absorbers and benzophenone-based ultraviolet absorbers can be exemplified. Furthermore, a lactone-based stabilizer can also be added. These can be used alone or in combination.

[0055] As stabilizers, commercially available products can be used. For example, Sumilizer GM (trade name), Sumilizer TPD (trade name), and Sumilizer TPS (trade name) manufactured by Sumitomo Chemical Co., Ltd., Irganox 1010 (trade name), Irganox HP2225FF (trade name), Irgafos 168 (trade name), and Irganox 1520 (trade name) manufactured by Ciba Specialty Chemicals, Adeka Stab AO-60 (trade name) of ADEKA, JF77 (trade name) and JP-650 (trade name) manufactured by Johoku Chemical Co., Ltd. can be exemplified. These stabilizers can be used alone or in combination.

[0056] The hot melt adhesive of the embodiment of the present invention can further contain a fine particle filler. The fine particle filler may be a commonly used one, and is not particularly limited as long as the hot melt adhesive aimed at by the present invention can be obtained. Examples of the "fine particle filler" include mica, calcium carbonate, kaolin, talc, titanium oxide, diatomaceous earth, urea resin, styrene beads, fired clay, starch, etc. These shapes are preferably spherical, and their dimensions (diameter in the case of spherical) are not particularly limited.

[0057] The hot melt adhesive of the embodiment of the present invention can be produced by using a generally known method for producing a hot melt adhesive and blending (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, and (C) a tackifying resin, and further, if necessary, (D) wax and / or the above various additives. For example, the above components can be blended in predetermined amounts and heated and melted for production. As long as the target hot melt adhesive can be obtained, the order of adding each component, the heating method, etc. are not particularly limited.

[0058] The method of applying the hot melt adhesive is not particularly limited as long as the intended paper product can be obtained, but hot melt applicators are widely used. Examples of hot melt applicators include, for example, ProBlue P4 Melt (trade name) and ProBlue P10 Melt (trade name) manufactured by Nordson Corporation.

[0059] The coating methods are roughly classified into, for example, contact coating and non-contact coating. "Contact coating" refers to a coating method in which an ejector is brought into contact with a member or a film when applying a hot melt adhesive, and "non-contact coating" refers to a coating method in which an ejector is not brought into contact with a member or a film when applying a hot melt adhesive. Examples of contact coating methods include, for example, slot coater coating and roll coater coating, and examples of non-contact coating methods include, for example, spiral coating that can be applied in a spiral shape, omega coating and control seam coating that can be applied in a wave shape, slot spray coating and curtain spray coating that can be applied in a planar shape, dot coating that can be applied in a dot shape, bead coating that can be applied in a linear shape, and the like.

[0060] When applying the hot melt adhesive of the embodiment of the present invention with a hot melt applicator (even when the hot melt adhesive is discharged horizontally with respect to the ground by the hot melt applicator for coating), almost no filamentous material of the hot melt adhesive is discharged. Therefore, the adherend and the applicator are not soiled with the filamentous material.

[0061] The hot melt adhesive of the embodiment of the present invention is widely used, for example, in electronic components, woodworking, building materials, sanitary materials, paper products, etc., but can be suitably used for manufacturing paper products and is useful as a hot melt adhesive for paper products.

[0062] The paper products according to the embodiments of the present invention refer to paper products manufactured using the above-described hot melt adhesive. The type of paper product is not particularly limited as long as it is manufactured using the above-described hot melt adhesive. Specifically, for example, bookbinding, calendars, corrugated cardboard, and cartons can be exemplified. Considering the characteristics of the hot melt adhesive according to the embodiments of the present invention, thick papers such as corrugated cardboard and cartons are particularly effective as the paper products according to the embodiments of the present invention.

Examples

[0063] Hereinafter, for the purpose of explaining the present invention in more detail and more specifically, examples will be used to explain the present invention. These examples are for explaining the present invention and do not limit the present invention in any way. The components to be blended in the hot melt adhesive are shown below.

[0064] (A) Ethylene / olefin copolymer having 3 to 20 carbon atoms (A1) Ethylene / octene copolymer (1-octene content: 35 to 37% by mass, melt flow rate: 1000 g / 10 min, Affinity GA1900 (trade name) manufactured by Dow Chemical Company) (A2) Ethylene / octene copolymer (1-octene content: 35 to 37% by mass, melt flow rate: 500 g / 10 min, Affinity GA1950 (trade name) manufactured by Dow Chemical Company) (A3) Ethylene / octene copolymer (1-octene content: 35 to 37% by mass, melt flow rate: 1200 g / 10 min, Affinity GA1875 (trade name) manufactured by Dow Chemical Company) (A4) Ethylene / octene copolymer (1-octene content: 30 to 40% by weight, melting point: 68 °C, melt flow rate: 660 g / 10 min, Affinity GA1000R (trade name) manufactured by Dow Chemical Company) (A5) Ethylene / propylene copolymer (ethylene content: 6.0% by mass, melting point: 97 °C, melt viscosity at 190 °C: 1200 mPas, Vistamax 88880 (trade name) manufactured by ExxonMobil) (A6) Ethylene / hexene copolymer (Nipolon Z HM510R (trade name) manufactured by Tosoh Corporation)

[0065] (B) Ethylene / carboxylic acid ester copolymer (B1) Ethylene / (meth)acrylic acid ester copolymer having a content of structural units derived from (meth)acrylic acid ester of 2 to 24% by mass (B1-1) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 20% by mass, melt flow rate: 20 g / 10 min, Acryft WH401-F (trade name) manufactured by Sumitomo Chemical Co., Ltd.) (B1-2) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 20% by mass, melt flow rate: 2 g / 10 min, Acryft WH206-F (trade name) manufactured by Sumitomo Chemical Co., Ltd.) (B1-3) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 10% by mass, melt flow rate: 7 g / 10 min, Acryft WH301-F (trade name) manufactured by Sumitomo Chemical Co., Ltd.) (B1-4) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 5% by mass, melt flow rate: 2 g / 10 min, Acryft WD203-1 (trade name) manufactured by Sumitomo Chemical Co., Ltd.) (B1-5) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 24% by mass, melt flow rate: 2 g / 10 min, Lotryl 24MA02N (trade name) manufactured by Arkema) (B1-6) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 20% by mass, melt flow rate: 8 g / 10 min, Rotader 4503 (trade name) manufactured by Arkema) (B1-7) Ethylene / butyl acrylate copolymer (butyl acrylate content: 17% by mass, melt flow rate: 7 g / 10 min, Lotryl 17BA07N (trade name) manufactured by Arkema) (B1-8) Ethylene / ethyl acrylate copolymer (ethyl acrylate content: 20% by mass, melt flow rate: 20 g / 10 min, DPDJ-9169 (trade name) manufactured by Dow Chemical Company) (B1-9) Ethylene / ethyl acrylate copolymer (ethyl acrylate content: 7% by mass, melt flow rate: 4 g / 10 min, NUC-6220 (trade name) manufactured by The Dow Chemical Company) (B1-10) Ethylene / ethyl acrylate copolymer (ethyl acrylate content: 6.5% by mass, melt flow rate: 200 g / 10 min, Rotader 8200 (trade name) manufactured by Arkema)

[0066] (B2) Ethylene / carboxylic acid ester copolymer other than component (B1) (B2-1) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 32% by mass, melt flow rate: 450 g / 10 min, Acrifto CM5022 (trade name) manufactured by Sumitomo Chemical Co., Ltd.) (B2-2) Ethylene / methyl methacrylate copolymer (methyl methacrylate content: 28% by mass, melt flow rate: 150 g / 10 min, Acrifto CM5023 (trade name) manufactured by Sumitomo Chemical Co., Ltd.) (B2-3)) Ethylene / butyl acrylate copolymer (butyl acrylate content: 35% by mass, melt flow rate: 320 g / 10 min, Rotril 35BA320 (trade name) manufactured by Arkema) (B2-4) Ethylene / butyl acrylate copolymer (butyl acrylate content: 35% by mass, melt flow rate: 40 g / 10 min, Rotril 35BA40 (trade name) manufactured by Arkema) (B2-5) Ethylene / butyl acrylate copolymer (butyl acrylate content: 28% by mass, melt flow rate: 175 g / 10 min, Rotril 28BA175 (trade name) manufactured by Arkema)

[0067] (C) Tackifying resin (C1) Partially hydrogenated tackifying resin (C1-1) Hydrogenated alicyclic / aromatic copolymer hydrocarbon resin (softening point: 103 °C, T-REZ HC103 (trade name) manufactured byENEOS) (C2) Fully hydrogenated tackifying resin (C2-1) Hydrogenated alicyclic hydrocarbon resin (softening point: 103 °C, T-REZ HA103 (trade name) manufactured byENEOS) (C2-2) Hydrogenated alicyclic hydrocarbon resin (softening point: 125°C, T-REZ HA125 (trade name) manufactured byENEOS Corporation) (C2-3) Hydrogenated alicyclic hydrocarbon resin (softening point: 125°C, Imarube P125 (trade name) manufactured by Idemitsu Kosan Co., Ltd.)

[0068] (D) Wax (D1) Fischer-Tropsch wax (melting point: 108°C, penetration: 2, Sasol H1 (trade name) manufactured by Sasol) (D2) Fischer-Tropsch wax (melting point: 112°C, penetration: 2, Sasol C105 (trade name) manufactured by Sasol) (D3) Fischer-Tropsch wax (melting point: 80°C, penetration: 2, Sasol C80 (trade name) manufactured by Sasol) (D4) Paraffin wax (melting point: 69°C, penetration: 12, Paraffin 155F (trade name) manufactured by Nippon Seiro Co., Ltd.) (D5) Microcrystalline wax (melting point: 84°C, penetration: 12, Himic 1080 (trade name) manufactured by Nippon Seiro Co., Ltd.) (D6) Polyethylene wax (melting point: 109°C, penetration: 7, Hiwax 320P (trade name) manufactured by Mitsui Chemicals, Inc.) (D7) Polypropylene wax (melting point: 140 - 148°C, penetration: 1 or less, Hiwax NP105 (trade name) manufactured by Mitsui Chemicals, Inc.)

[0069] (E) Stabilizer (E1) Phenolic antioxidant (ADEKA STAB AO-60 (trade name) manufactured by ADEKA Corporation) (E2) Phosphorus-based antioxidant (JP650 manufactured by Johoku Chemical Co., Ltd.) (E3) Sulfur-based antioxidant (Sumilizer TPS manufactured by Sumitomo Chemical Co., Ltd.)

[0070] The above components were melt-mixed at the ratios (parts by mass) shown in Tables 1 to 2. Using a universal stirrer, each component was melt-mixed at about 145°C for about 1 hour to produce the hot-melt adhesives of Examples 1 to 13 and Comparative Examples 1 to 5. For the hot-melt adhesives of the examples and comparative examples, the adhesiveness, thermal stability, setting property, and thread-drawing property were evaluated using the following methods. For adhesiveness, the hot-melt adhesive was applied to a K-liner corrugated board, and then bonded to another K-liner corrugated board to obtain a sample. For thermal stability, the hot-melt adhesive was stored in an atmosphere of 150°C for 1 week (168 hours), and the viscosity change rate and the generation of carbides were confirmed. For the setting property, samples were prepared by varying the pressing time, and then evaluated by a peel test. For the thread-drawing property, the discharge state of the hot-melt adhesive was confirmed under the condition of 180°C. The outlines of each evaluation are described below.

[0071] <Adhesiveness> (Sample Preparation) The hot-melt adhesive melted at 180°C was applied to a K-liner corrugated board at a coating amount of 2 g / m². After 3 seconds elapsed as the open time, under the conditions of a pressing pressure of 1 kg / 25 cm² 2 and a setting time (pressing time) of 10 seconds, it was bonded to another K-liner corrugated board to prepare a sample. For each hot-melt adhesive, at least 3 samples were prepared. (Evaluation Method) The prepared samples were cured in a thermostatic bath set at 60°C, 23°C, or -10°C for 24 hours. Then, in that atmosphere, they were forcibly peeled by hand peeling. The ratio of the destruction of the K-liner corrugated board in the total adhesive area was defined as the material breakage rate (the ratio at which the material was broken), and the state of the adhesive surface of the K-liner corrugated board was evaluated. The evaluation criteria are as follows. ◎: The material breakage rate is higher than 80% ○: The material breakage rate is 60% - 80% △: The material breakage rate is 40% or more and less than 60% ×: The material breakage rate is less than 40%

[0072] <Thermal Stability> (Sample Preparation) 50 g of each hot melt adhesive was placed in a 100 cc glass bottle and stored in a thermostat at 150 °C for 168 hours to prepare samples. (Evaluation method) Samples of the hot melt adhesive stored in a thermostat at 150 °C for 168 hours were visually observed to check for the presence of carbides and the separation state of the hot melt adhesive. The evaluation criteria are as follows. Occurrence of carbides ◎: No carbides ○: Slight presence of carbides △: Presence of carbides ×: Marked presence of carbides Separation state ◎: No sediment ○: Slight presence of sediment △: Presence of carbides ×: Marked presence of sediment

[0073] <Set property> (Sample preparation) The hot melt adhesive melted at 180 °C was applied to K-liner cardboard at a coating rate of 2 g / m, and after 3 seconds elapsed as the open time, with a pressing pressure of 1 kg / 25 cm 2 the setting time (pressing time) was varied, and it was bonded to another piece of K-liner cardboard to prepare samples. (Evaluation method) The prepared samples were immediately forcefully peeled in the vertical direction (at 90°) at a constant speed using a Kanebo tester (trade name) manufactured by Meck, and the peel strength was measured. Furthermore, the state of the K-liner cardboard after peeling was visually observed. The shortest time for the peel strength to be 6 kgf or more and for the K-liner cardboard to break (breakage rate: 40% or more) was taken as the setting time, and that time was recorded. The evaluation criteria are as follows. ◎: Setting time less than 1.0 second ○: Setting time of 1.0 - 1.5 seconds ×: Setting time longer than 1.5 seconds

[0074] <Thread-dragging reduction property> The hot melt adhesive was intermittently applied vertically to the adherend 20 cm away from the tip of the hot melt gun. The state of the falling objects between the hot melt gun and the adherend was visually observed to evaluate the thread-dragging property. (Measurement conditions) Temperature setting: 180 °C for all of the tank, hose, and nozzle Nozzle diameter: 14 / 1000 inch Nozzle: 4 orifices (number of discharge ports: 4) Coating pressure: 0.3 MPa Number of coating shots: 180 shots / 1 minute for each of the 4 orifices The evaluation criteria are as follows. ◎: The shape of the falling objects is granular. ○: The shape of the falling objects is mostly granular, but slightly filamentous ones are mixed in. △: The shape of the falling objects is a mixture of granular and filamentous. ×: The shape of the falling objects is filamentous.

[0075]

Table 1

[0076]

Table 2

[0077] As shown in Tables 1 to 2, the hot melt adhesives of Examples 1 to 13 contain (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B1) an ethylene / (meth)acrylate copolymer having a content of structural units derived from (meth)acrylate of 2 to 24% by mass, and (C) a tackifying resin, and thus are excellent in the overall balance of adhesiveness, thermal stability, setting property, and thread-dragging property.

[0078] In particular, the hot melt adhesives of Examples 1 to 3 reduce thread-dragging at a higher level while improving thermal stability. The hot melt adhesives of the examples are useful for paper processing fields, particularly for coating thick papers such as corrugated board and carton.

[0079] On the other hand, as shown in Table 2, the hot melt adhesives of Comparative Examples 1 to 5 do not contain the component (B1), and thus any one of the adhesiveness, thermal stability, and yarn draw reducing property is significantly inferior.

Industrial Applicability

[0080] The present invention can provide a hot melt adhesive and a paper product coated with the hot melt adhesive. The paper product of the embodiment of the present invention is particularly effective when manufactured from thick paper such as corrugated board and carton.

Claims

1. It contains (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, (C) a tackifier resin, and (D) a wax, The (B) ethylene / carboxylic acid ester copolymer contains (B1) an ethylene / (meth)acrylic acid ester copolymer having a content of structural units derived from (meth)acrylic acid ester of 2 to 24% by mass, Per 100 parts by mass in total of (A) an ethylene / olefin copolymer having 3 to 20 carbon atoms, (B) an ethylene / carboxylic acid ester copolymer, (C) a tackifier resin, and (D) a wax, (A) the ethylene / olefin copolymer having 3 to 20 carbon atoms contains 20 to 50 parts by mass, (B1) the ethylene / (meth)acrylic acid ester copolymer contains 1 to 10 parts by mass, and (C) the tackifier resin contains 30 to 60 parts by mass, A hot melt adhesive.

2. The hot melt adhesive according to Claim 1, wherein the (B1) ethylene / (meth)acrylic acid ester copolymer contains at least one selected from ethylene / methyl methacrylate copolymer, ethylene / butyl acrylate copolymer, and ethylene / ethyl acrylate.

3. The hot melt adhesive according to Claim 1 or 2, wherein the (C) tackifier resin contains (C1) a partially hydrogenated tackifier resin and (C2) a fully hydrogenated tackifier resin.

4. A paper product having the hot melt adhesive according to any one of Claims 1 to 3.

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